Abstract
A detector for optical detection of at least one object, the detector including: at least one optical sensor including at least one sensor region. The optical sensor is configured to generate at least one sensor signal dependent on an illumination of the sensor region by an incident modulated light beam. The sensor signal is dependent on a modulation frequency of the light beam. The sensor region includes at least one capacitive device including at least two electrodes. At least one insulating layer and at least one photosensitive layer are embedded between the electrodes, wherein at least one of the electrodes is at least partially optically transparent for the light beam. The detector further includes at least one evaluation device configured to generate at least one item of information on a position of the object by evaluating the sensor signal.
Claims
1-20. (canceled)
21. A detector for optically detecting at least one object, comprising: at least one optical sensor comprising at least one sensor region, wherein the optical sensor is configured to generate at least one sensor signal dependent on an illumination of the sensor region by an incident modulated light beam, wherein the sensor signal is dependent on a modulation frequency of the light beam, wherein the sensor region comprises at least one capacitive device, the capacitive device comprising at least two electrodes, wherein at least one insulating layer and at least one photosensitive layer are embedded between the electrodes, wherein at least one of the electrodes is at least partially optically transparent for the light beam; and at least one evaluation device configured to generate at least one item of information on a position of the object by evaluating the sensor signal.
22. The detector according to claim 21, wherein the optical sensor is selected from: at least one longitudinal optical sensor configured to generate at least one longitudinal sensor signal, wherein the longitudinal sensor signal, given same total power of the illumination, is further dependent on a beam cross-section of the light beam in the sensor region, wherein the evaluation device is configured to generate at least one item of information on a longitudinal position of the object by evaluating the longitudinal sensor signal; or at least one transversal optical sensor, wherein one of the electrodes is an electrode layer having a low electrical conductivity configured to determine a position at which the incident light beam is impinged on the sensor region, wherein the transversal optical sensor is configured to generate at least one transversal sensor signal dependent on the position at which the incident light beam is impinged on the sensor region, wherein the evaluation device is configured to generate at least one item of information on a transversal position of the object by evaluating the transversal sensor signal.
23. The detector according to claim 21, wherein the insulating layer comprises an insulating material or an electrically insulating component.
24. The detector according to claim 23, wherein the insulating material comprises at least one transparent insulating metal-containing compound, wherein the metal-containing compound comprises a metal selected from the group: Al, Ti, Ta, Mn, Mo, Zr, Hf, La, Y, and W; wherein the at least one metal-containing compound is selected from the group: an oxide, a hydroxide, a chalcogenide, a pnictide, a carbide, or a combination thereof.
25. The detector according to claim 24, wherein the insulating material is obtainable by atomic layer deposition.
26. The detector according to claim 21, wherein the photosensitive layer is provided as one or more of: at least one layer comprising at least one photoconductive material in a nanoparticulate form; at least two individual photoconductive layers comprising at least one photoconductive material and provided as adjacent layers having at least one boundary, wherein the photoconductive layers are configured to generate a junction at the boundary between the adjacent layers; at least one semiconductor absorber layer; and at least one organic photosensitive layer comprising at least one electron donor material and at least one electron acceptor material.
27. The detector according to claim 26, wherein the photoconductive material is an inorganic photoconductive material selected from a group consisting of group IV elements, group IV compounds, III-V compounds, group II-VI compounds, and chalcogenides.
28. The detector according to claim 26, wherein the semiconductor absorber layer comprises one or more of crystalline silicon (c-Si), microcrystalline silicon (c-Si), hydrogenated microcrystalline silicon (c-Si:H), amorphous silicon (a-Si), hydrogenated amorphous silicon (a-Si:H), an amorphous silicon carbon alloy (a-SiC), a hydrogenated amorphous silicon carbon alloy (a-SiC:H), a germanium silicon alloy (a-GeSi), or a hydrogenated amorphous germanium silicon alloy (a-GeSi:H).
29. The detector according to claim 26, wherein the organic photosensitive layer comprises an individual donor material layer comprising the donor material and an individual acceptor material layer comprising the acceptor material, or wherein the donor material and the acceptor material in the organic photosensitive layer are arranged as a single layer comprising the donor material and the acceptor material.
30. The detector according to claim 29, wherein the donor material is selected from a small organic molecule comprising a phthalocyanine derivative, an oligothiophene, an oligothiophene derivative, a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative, an aza-BODIPY derivative, a squaraine derivative, a diketopyrrolopyrrol derivative, or a benzdithiophene derivative, and wherein the acceptor material is selected from C60, C70, or a perylene derivative.
31. The detector according to claim 28, wherein the electron donor material comprises an organic donor polymer and wherein the electron acceptor material comprises a fullerene-based electron acceptor material, wherein the organic donor polymer is selected from one or more of: poly[3-hexylthiophene-2,5.diyl] (P3HT), poly[3-(4-n-octyl)-phenylthiophene] (POPT), poly[3-10-n-octyl-3-phenothiazine-vinylenethiophene-co-2,5-thiophene] (PTZV-PT), poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bldithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl] (PTB7), poly[thiophene-2,5-diyl-alt-[5,6-bis(dodecyloxy)benzo[c][1,2,5]thiadiazole]-4,7-diyl] (PBT-T1), poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-bldithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), poly[5,7-bis(4-decanyl-2-thienyl)-thieno(3,4-b)diathiazolethiophene-2,5] (PDDTT), poly[N-9-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2,1, 3-benzothiadiazole)] (PCDTBT), or poly[(4,4-bis(2-ethyl-hexyl)dithieno[3,2-b;2,3-d]silole)-2,6-diyl-alt-(2,1,3-benzothia-diazole)-4,7-diyl] (PSBTBT), poly[3-phenyl hydrazone thiophene] (PPHT), poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-1,2-ethenylene-2,5-dimethoxy-1,4-phenylene-1,2-ethenylene] (M3EH-PPV), poly[2-methoxy-5-(3,7-dimethyl-octyl-oxy)-1,4-phenylenevinylene] (MDMO-PPV), poly[9,9-di-octylfluorene-co-bis-N,N-4-butylphenyl-bis-N,N-phenyl-1,4-phenylenediamine] (PFB), or a derivative, a modification, or a mixture thereof, and wherein the fullerene-based electron acceptor material is selected from one or more of [6,6]-phenyl-C61-butyric acid methyl ester (PC60BM), [6,6]-Phenyl-C71-butyric acid methyl ester (PC70BM), [6,6]-phenyl C84 butyric acid methyl ester (PC84BM), an indene-C60 bisadduct (ICBA), or a derivative, a modification, or a mixture thereof.
32. The detector according to claim 21, wherein the capacitive device further comprises at least one charge-carrier transporting layer, wherein the charge-carrier transporting layer is located between the photosensitive layer and one of the electrodes.
33. The detector according to claim 21, wherein the detector further comprises at least one modulation device for modulating the illumination.
34. A human-machine interface for exchanging at least one item of information between a user and a machine, wherein the human-machine interface comprises: at least one detector according to claim 21 relating to a detector, wherein the human-machine interface is configured to generate at least one item of geometrical information of the user by the detector, wherein the human-machine interface is configured to assign to the geometrical information at least one item of information.
35. An entertainment device for carrying out at least one entertainment function, wherein the entertainment device comprises: at least one human-machine interface according to claim 34, wherein the entertainment device is configured to enable at least one item of information to be input by a player by the human-machine interface, wherein the entertainment device is configured to vary the entertainment function in accordance with the information.
36. A tracking system for tracking position of at least one movable object, the tracking system comprising: at least one detector according to claim 21; at least one track controller, wherein the track controller is configured to track a series of positions of the object, each position comprising at least one item of information on at least a position of the object at a specific point in time.
37. A scanning system for determining at least one position of at least one object, the scanning system comprising: at least one detector according to claim 21; at least one illumination source configured to emit at least one light beam configured for an illumination of at least one dot located at at least one surface of the at least one object, wherein the scanning system is designed to generate at least one item of information about the distance between the at least one dot and the scanning system by using the at least one detector.
38. A camera for imaging at least one object, the camera comprising at least one detector according to claim 21.
39. A method for an optical detection of at least one object, the method comprising: generating at least one sensor signal by using at least one optical sensor comprising a sensor region, wherein the sensor signal is dependent on an illumination of the sensor region of the optical sensor by an incident modulated light beam, wherein the sensor signal is further dependent on a modulation frequency of the light beam, wherein the sensor region comprises at least one capacitive device, the capacitive device comprising at least two electrodes, wherein at least one insulating layer and at least one photosensitive layer are embedded between the electrodes, wherein at least one of the electrodes is at least partially optically transparent for the light beam; and evaluating the sensor signal of the optical sensor by determining an item of information on the position of the object from the sensor signal.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0288] Further optional details and features of the invention are evident from the description of preferred exemplary embodiments which follows in conjunction with the dependent claims. In this context, the particular features may be implemented alone or with features in combination. The invention is not restricted to the exemplary embodiments. The exemplary embodiments are shown schematically in the figures. Identical reference numerals in the individual figures refer to identical elements or elements with identical function, or elements which correspond to one another with regard to their functions.
[0289] Specifically, in the figures:
[0290] FIG. 1 illustrates a preferred exemplary embodiment of a detector for optical detection of at least one object according to the present invention in a schematic fashion, wherein the detector comprises at least one longitudinal optical sensor having a sensor region comprising at least one capacitive device;
[0291] FIGS. 2A and 2B each illustrate a cross section of a particularly preferred exemplary setup of the capacitive device for application in a longitudinal optical sensor in a schematic fashion;
[0292] FIGS. 3A to 3N illustrate cross sections of two preferred examples of a first exemplary embodiment of the capacitive device for application in a longitudinal optical sensor in a schematic fashion (FIGS. 3A and 3B), the photocurrent as a function of distance of the sensor region to the object (FIGS. 3C, 3G, 3J, 3K and 3N), the photocurrent as a function of a modulation frequency of an incident modulated light beam (FIGS. 3D, 3H, 3I, 3L and 3M), and a current vs. voltage characterization of the capacitive device (FIGS. 3E and 3F);
[0293] FIGS. 4A to 4G illustrate a cross section of a preferred example of a second exemplary embodiment of the capacitive device for application in a longitudinal optical sensor in a schematic fashion (FIG. 4A), the photocurrent as a function of distance of the sensor region to the object (FIGS. 4 B to 4E), and the photocurrent as a function of a modulation frequency of an incident modulated light beam (FIGS. 4F and 4G);
[0294] FIGS. 5A to 51 illustrate cross sections of two preferred examples of a third exemplary embodiment of the capacitive device 134 for application in a longitudinal optical sensor in a schematic fashion (FIGS. 5A and 5B), the photocurrent as a function of distance of the sensor region to the object (FIGS. 5C to 5G), and the photocurrent as a function of a modulation frequency of an incident modulated light beam (FIGS. 5H and 51);
[0295] FIGS. 6A to 6E illustrate a cross section of a preferred example of a fourth exemplary embodiment of the capacitive device for application in a longitudinal optical sensor in a schematic fashion (FIG. 6A), the photocurrent as a function of distance of the sensor region to the object (FIGS. 6B and 6C), and the photocurrent as a function of a modulation frequency of an incident modulated light beam (FIGS. 6D and 6E);
[0296] FIGS. 7A to 71 illustrate cross sections of two preferred examples of a fifth exemplary embodiment of the capacitive device for application in a longitudinal optical sensor in a schematic fashion (FIGS. 7A and 7B), the photocurrent as a function of distance of the sensor region to the object (FIGS. 7C, 7E and 7H), the photocurrent as a function of a modulation frequency of an incident modulated light beam (FIGS. 7D, 7F and 7I), and a current vs. voltage characterization of the capacitive device (FIG. 7G);
[0297] FIG. 8 shows an exemplary embodiment of the optical detector and of a detector system, a human-machine interface, an entertainment device, a tracking system, and a camera in a schematic fashion, each comprising the optical detector according to the present invention;
[0298] FIG. 9A to 9C illustrate a cross section of a preferred example of a sixth exemplary embodiment of the capacitive device for application in a transversal optical sensor in a schematic fashion (FIG. 9A) and a number of measurement point positions as determined by using the detector according to the present invention compared with actual positions otherwise available (FIGS. 9B and 9C); and
[0299] FIGS. 10A to 10C illustrate cross sections of preferred examples of a seventh exemplary embodiment of the capacitive device in a transversal optical sensor in a schematic fashion.
EXEMPLARY EMBODIMENTS
[0300] FIG. 1 illustrates, in a highly schematic illustration, a first exemplary embodiment of a detector 110 according to the present invention for determining a position of at least one object 112. However, other embodiments are feasible. In general, the Figures and the various elements as displayed therein are not to scale.
[0301] The detector 110 as schematically depicted in FIG. 1 comprises at least one longitudinal optical sensor 114, which, in this particular embodiment, is arranged along an optical axis 116 of the detector 110. Specifically, the optical axis 116 may be an axis of symmetry and/or rotation of the setup of the optical sensors 114. The optical sensors 114 may be located inside a housing 118 of the detector 110. Further, at least one transfer device 120 may be comprised, preferably a refractive lens 122. An opening 124 in the housing 118, which may, particularly, be located concentrically with regard to the optical axis 116, preferably, defines a direction of view 126 of the detector 110. A coordinate system 128 may be defined, in which a direction parallel or antiparallel to the optical axis 116 is defined as a longitudinal direction, whereas directions perpendicular to the optical axis 116 may be defined as transversal directions. In the coordinate system 128, symbolically depicted in FIG. 1, the longitudinal direction is denoted by z while the transversal directions are denoted by x and y, respectively. However, other types of coordinate systems 128 may also be feasible.
[0302] Further, the longitudinal optical sensor 114 is designed to generate at least one longitudinal sensor signal in a manner dependent on an illumination of a sensor region 130 comprised by the longitudinal optical sensor 114 by an incident modulated light beam 132. Thus, according to the FiP effect, the longitudinal sensor signal, given the same total power of the illumination, is dependent on a beam cross-section of the light beam 132 in the respective sensor region 130 and on a modulation frequency of the modulated light beam 132. According to the present invention and in particular contrast to the optical detector as disclosed in WO 2016/092454 A1, the sensor region 130 of the longitudinal optical 110 sensor comprises at least one capacitive device 134, in particular, in one of the preferred embodiments which are described in FIG. 2A, 2B, 3A, 3B, 4A, 5A, 5B, 6A, 7A, 7B, 10A, 10B or 10C or a combination thereof in more detail.
[0303] The modulated light beam 132 for illumining the sensor region 130 of the longitudinal optical sensor 114 may be generated by a light-emitting object 112 being capable of providing the illumination in a modulated manner. Alternatively or in addition, the light beam 132 may be generated by a separate illumination source 136, which may include an ambient light source and/or an artificial light source 138, such as a light-emitting diode (LED) 140, which may be adapted to illuminate the object 112 in a fashion that the object 112 may be able to reflect at least a part of the light generated by the illumination source 136 in a manner that the light beam 132 may reach the sensor region 130 of the longitudinal optical sensor 114, preferably by entering the housing 118 of the optical detector 110 through the opening 124 along the optical axis 116.
[0304] Thus, the illumination source 136 may be a modulated light source 142, wherein one or more modulation properties of the illumination source may be controlled by at least one modulation device 144. Alternatively or in addition, the modulation may be effected in a first beam path 146 between the illumination source and the object 112 and/or in a second beam path 148 between the object 112 and the longitudinal optical sensor 114. Further possibilities may be conceivable. In this particular embodiment, it may be advantageous to take into account one or more of the modulation properties, in particular the modulation frequency, when evaluating the sensor signal of the transversal optical sensor 114 for determining the at least one item of information on the position of the object 112 in an evaluation device 150.
[0305] The evaluation device 150 is, generally, designed to generate at least one item of information on a position of the object 112 by evaluating the sensor signal of the longitudinal optical sensor 114. Herein, the evaluation device 150 may comprise one or more electronic devices and/or one or more software components, in order to evaluate the sensor signals, which are symbolically denoted by a longitudinal evaluation unit 152 (denoted by z). For this purpose, the evaluation device 150 may, preferably, be adapted to determine the at least one item of information on the longitudinal position of the object 112 by comparing more than one longitudinal sensor signals of the longitudinal optical sensor 114. As explained above, the longitudinal sensor signal as provided by the longitudinal optical sensor 114 upon impingement by the modulated light beam 132 depends on an illumination of the sensor region 130 by the light beam 132, wherein the longitudinal sensor signal, given the same total power of the illumination, is dependent on a beam cross-section of the light beam 132 in the sensor region 130 and on a modulation frequency of the light beam 132. As for example explained in WO 2012/110924 A1 in more detail, the evaluation device 150 may, thus, be adapted to determine the at least one item of information on the longitudinal position of the object 112 by comparing more than one longitudinal sensor signals of the longitudinal optical sensor 114.
[0306] Generally, the evaluation device 150 may be part of a data processing device and/or may comprise one or more data processing devices. The evaluation device 150 may be fully or partially integrated into the housing 118 and/or may fully or partially be embodied as a separate device which is electrically connected in a wireless or wire-bound fashion, such as via one or more signal leads 154, to the longitudinal optical sensor 114. The evaluation device 150 may further comprise one or more additional components, such as one or more electronic hardware components and/or one or more software components, such as one or more measurement units and/or one or more evaluation units (not depicted in FIG. 1) and/or one or more controlling units, such as the modulation device 144 being adapted to control the modulation properties of the modulated light source 142. Further, the evaluation device 150 may be a computer 156 and/or may comprise a computer system comprising a data processing device 158. However, other embodiments may also be feasible.
[0307] In the preferred embodiment of FIG. 1, the optical detector 110 further comprises at least one transversal optical sensor 160 which, in this particular embodiment, is also arranged along an optical axis 116 of the detector 110. Herein, the transversal optical sensor 160 may, preferably, be adapted to determine a transversal position of the modulated light beam 132 traveling from the object 112 to the optical detector 110. Herein, the transversal position may be a position in at least one dimension perpendicular an optical axis 116 of the optical detector 110, in this particular embodiment denoted by x and y, respectively, according to the coordinate system 128. The transversal optical sensor 160 as used here may, preferably, exhibit a setup as illustrated below in the exemplary embodiment of FIG. 9. However, other setups may also be feasible, such as by using a known position sensitive device (PSD), in particular a photodetector as, for example, disclosed in WO 2012/110924 A1 or WO 2014/097181 A1, or a photoconductor as, for example, disclosed in WO 2016/120392 A1. However, other setups of the transversal optical sensor 160 may also be applicable here.
[0308] For the purpose of determining the transversal position, the transversal optical sensor 160 may further be adapted to generate at least one transversal sensor signal. The transversal sensor signal may be transmitted in a wireless or wire-bound fashion, such as via one or more signal leads 154, to the evaluation device 150, which may further be designed to generate at least one item of information on a transversal position of the object 112 by evaluating the transversal sensor signal. For this purpose, the evaluation device 150 may further comprise one or more electronic devices and/or one or more software components, in order to evaluate the sensor signals, which are symbolically denoted by a transversal evaluation unit 162 (denoted by z). Further, by combining results derived by the evolution units 152, 162, position information 164, preferably three-dimensional position information, symbolically denoted here by x, y, z, may thus be generated.
[0309] The optical detector 110 may have a straight beam path or a tilted beam path, an angulated beam path, a branched beam path, a deflected or split beam path or other types of beam paths. Further, the light beam 132 may propagate along each beam path or partial beam path once or repeatedly, unidirectionally or bidirectionally. Thereby, the components listed above or the optional further components listed in further detail below may fully or partially be located in front of the longitudinal optical sensors 114 and/or behind the longitudinal optical sensors 114.
[0310] FIGS. 2A and 2B each illustrate a cross section of an exemplary setup of a preferred example of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a highly schematic fashion. As depicted in FIG. 2A, the capacitive device 134 has an optically transparent first electrode 166. Preferably, the capacitive device 134 may be arranged in a manner that the optically transparent first electrode 166 may be located towards the incident modulated light beam 132. The optically transparent first electrode 166 may comprise a layer of one or more transparent conductive oxides 168 (TOO), in particular indium-doped tin oxide (ITO). However, other kinds of optically transparent materials, such as fluorine-doped tin oxide (FTO) or aluminum-doped zinc oxide (AZO), may also be suitable for this purpose. In order to be able to using a minimum of the optically transparent oxide 168 but still keep the optically transparent first electrode 166 mechanically stable, the optically transparent oxide 168 may be placed on top of an optically transparent substrate 170, in particular on top of a glass substrate 172, preferably by using a deposition method, such as a coating or an evaporation method. Alternatively, a quartz substrate or a substrate comprising an optically transparent but electrically insulating polymer, such as polyethylene terephthalate (PET), may also be used for this purpose.
[0311] Further, the capacitive device 134 has a second electrode 174, which may be optically intransparent, thus, allowing the modulated light beam 132 to be reflected here. Accordingly, the capacitive device 134 may be arranged in a manner that the optically intransparent second electrode 174 may be located away from the incident modulated light beam 132. However, in other embodiments, the second electrode 174 may also be at least partially transparent for the incident modulated light beam 132.
[0312] In order to provide the longitudinal optical sensor 114, the second electrode 174 may, in this particular embodiment, comprise a metal electrode 176, such as a silver (Ag) electrode, a platinum (Pt) electrode, a gold (Au) electrode, an aluminum (Al) electrode, or a molybdenum (Mo) electrode. However, other kinds of metals may also be feasible. Preferably, the metal electrode 176 may comprise a thin layer of metal which may be deposited onto a substrate, such as a further layer.
[0313] In order to provide the transversal optical sensor 160, the second electrode 174 may comprise a low electrical conductivity electrode which may be adapted to allow determining the position at which the charge was actually generated which can, reasonably, be considered as the position at which the incident light beam impinged the sensor region 130. For this purpose, the second electrode 174 may, additionally, be equipped with the at least one split electrode. For further details, reference may be made to the description of FIG. 9A below.
[0314] Further, the capacitive device 134 according to the present invention comprises an insulating layer 178 which may be provided in form of a dielectric material being located as intervening medium between the first electrode 166 and the second electrode 174. However, the insulating layer 178 may, alternatively or in addition, be provided in form of an electrically insulating component (not depicted here), such as a diode or an arrangement having a junction. Applying the insulating layer 178 having dielectric properties between the first electrode 166 and the second electrode 174 may be particularly advantageous since it may prevent the first electrode 166 and the second electrode 174 from achieving a direct electrical contact, thus, avoiding a short-cut between the first electrode 166 and the second electrode 174. In addition, depending on a permittivity of the insulating layer 178, the insulating layer 178 between the first electrode 166 and the second electrode 174 may, further, allow storing an increased amount of charge in the capacitive device 134 at a given voltage compared to a capacitive device which would have a vacuum located between its electrodes.
[0315] In the exemplary embodiment of FIG. 2A, the insulating layer 178 is an optically at least partially transparent insulating layer in order to allow the incident light beam 132 to at least partially traverse the insulating layer 178. Thus, the insulating layer 178 may, preferably, exhibit a transmittance which may be capable of decreasing the illumination power of the incident light beam 132 as little as possible over a spectral range of the incident light beam 132. As described elsewhere in this document in more detail, the insulating layer 178 which may exhibit optically at least partially transparent properties may, preferably, be chosen to be a transparent metal oxide, in particular, comprising a layer of aluminum oxide Al.sub.2O.sub.3 or zirconium dioxide ZrO.sub.2. However, other kinds of materials may also be used for the insulating layer 178.
[0316] In addition to the insulating layer 178, the capacitive device 134 according to the present invention, additionally, has at least one photosensitive layer 180 which comprises at least one material which is susceptible to an influence of the incident modulated light beam 132. As described elsewhere in this document, upon illumination of the photosensitive layer 180 by the incident modulated light beam 132, an amount of charge carriers is generated in the photosensitive layer 180, wherein the amount of the charge carriers which are generated in this fashion depends on the illumination of the photosensitive layer 180 and the frequency of modulation of the incident modulated light beam 132. Herein, the incident modulated light beam 132 may be considered as an alternating light beam being capable of generating the charge carriers in an alternating fashion, thus, giving rise to an alternating current (ac) in the capacitive device 134. As a result, the capacitive device 134 having the photosensitive layer 180 as described here allows the longitudinal optical sensor 114 to generate the at least one ac longitudinal sensor signal depending on both the illumination of the sensor region 130 and the frequency of modulation of the incident modulated light beam 132. Accordingly, the detector 110 comprising the capacitive device 134 exhibits the FiP effect which means that the longitudinal sensor signal provided by the capacitive device 134 may, thus, be in form of an ac photocurrent which decreases when the incident modulated incident light beam 134 is focused onto the photosensitive layer 180 as the sensor region 130 of the longitudinal optical sensor 114. As described elsewhere in this document in more detail, such as in the embodiments as schematically depicted in any one of FIG. 3A, 3B, 4A, 5A, 5B, 6A, 7A, 7B, 9A, 10A, 10B or 100, or a combination thereof, the photosensitive layer 180 may be implemented by using various setups.
[0317] In contrast to FIG. 2A, in the exemplary embodiment of the capacitive device 134 as depicted in FIG. 2B the incident modulated light beam 132, after having traversed the first transparent electrode 166, first impinges the photosensitive layer 180 before it may reach the insulating layer 178. Consequently, the insulating layer 178 may, in this particular embodiment, be or comprise an intransparent insulating layer which can, additionally, be capable of reflecting the incident light beam 132 into the photosensitive layer 180, thus, increasing the intensity of the light within the photosensitive layer 180. However, the insulating layer 178 may, nevertheless, also be or comprise a transparent insulating layer, in which case the incident light beam 132 may be reflected by the adjacent second electrode 174 into the photosensitive layer 180, thereby being capable of providing a comparative advantage. The arrangement as shown in FIG. 2B may, thus, allow using a wider range of materials for the insulating layer 178.
[0318] FIGS. 3A and 3B each illustrate a cross section of a preferred example of a setup of a first exemplary embodiment of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a schematic fashion while FIGS. 3C to 3N provide experimental results obtained for the capacitive device 134 as arranged accordingly.
[0319] According to FIGS. 3A and 3B, the first exemplary embodiment of the capacitive device 134 comprises the glass substrate 172 which is coated by the layer of the transparent conductive oxide (TCO) 168 comprising indium-doped tin oxide (ITO) in the example of FIG. 3A and fluorine-doped tin oxide (FTO) in the example of FIG. 3B. However, both materials can also be used in both examples. Alternatively, a layer of aluminum-doped zinc oxide (AZO) or of another TCO may also be used as the transparent conductive oxide 168. As an alternative to the glass substrate 172, a quartz substrate or a substrate comprising an optically transparent and electrically insulating polymer, such as polyethylene terephthalate (PET), may also be feasible.
[0320] Further, the capacitive device 134 in the first exemplary embodiment comprises a thin insulating aluminum oxide (Al.sub.2O.sub.3) layer having a thickness of approximately 120 nm as the insulating layer 178, wherein the Al.sub.2O.sub.3 layer which has been provided in this example by applying atomic layer deposition (ALD) at around 200 C. directly onto the ITO coated glass substrate 172. As will be demonstrated below in more detail, the Al.sub.2O.sub.3 (ALD) layer which has been found to exhibit excellent insulating properties even at thicknesses of 1 nm to 1000 nm, preferably of 10 nm to 250 nm, in particular of 20 nm to 150 nm, may allow for a facile preparation of a photoactive capacitor by additionally using a suitable material as the photosensitive layer 180.
[0321] For this purpose, the capacitive device 134 comprises, in addition to the thin insulating Al.sub.2O.sub.3 (ALD) layer, a layer of nanoparticulate lead sulfide (np-PbS) which acts as the photosensitive layer 180 in the capacitive device 134. Alternatively, the nanoparticulate lead sulfide may also be denominated as PbS nanoparticles or as PbS quantum dots, abbreviated to PbS-QDs. In this particular example, the photosensitive layer 180 comprises np-PbS, wherein the PbS nanoparticles exhibited a spherical shape combined with a narrow particle size distribution having a maximum at the particle size of 8 nm. These kinds of PbS nanoparticles are known to cover the infrared wavelength range of 1000 to 1600 nm in emission, wherein the absorption properties of the nanoparticles are determined by their particle size and a particle size of 8 nm is expected to achieve absorption around 1550 nm. The np-PbS was deposited from a suspension in octane by spin-coating (50 mg/ml np-PbS in octane, spun cast at 4000 rpm).
[0322] In order to facilitate a transport of the charge carriers generated in the photosensitive layer 180 from their place of generation within the photosensitive layer 180 to the adjacent metal electrode 176, the capacitive device 134 in the further example as illustrated in FIG. 3B further comprises a charge-carrier transporting layer 182 which is particularly configured for this purpose. In this embodiment, the charge-carrier transporting layer 182 comprises a hole transporting layer of molybdenum oxide (MoO.sub.3). Thus, a thin layer of approximately 15 nm MoO.sub.3 was deposited onto the np-PbS photosensitive layer 180 prior to depositing the thin layer of approximately 200 nm silver (Ag) onto the thin MoO.sub.3 layer. Possible material alternatives for the charge-carrier transporting layer 182 may be nickel oxide (NiO.sub.2), a poly-3,4-ethylenedioxy-thiophene (PEDOT), preferably PEDOT electrically doped with at least one counter ion, more preferably PEDOT doped with sodium polystyrene sulfonate (PEDOT:PSS), a polyaniline (PANI), or a polythiophene (PT). As a further alternative, a charge-carrier extraction layer (not depicted here) may also be feasible for facilitating the transport of the charge carriers generated in the photosensitive layer 180 from their place of generation to the electrode.
[0323] As a result, the incident modulated light beam 132 may generate holes as the charge carriers in the photosensitive layer 180 in the detector 110 comprising the capacitive device 134 of the first embodiment according to both examples of FIGS. 3A and 3B, wherein the amount of the charge carriers may vary with both the beam cross-section of the light beam 132 in the np-PbS layer and the modulation frequency of the incident modulated light beam 132. While the first effect can be seen in a variation of the alternating current (ac) photocurrent I.sub.p in nA with a distance d of the sensor region 130 to the object 112 in mm as depicted in FIG. 3C, the latter effect is illustrated in FIG. 3D which displays the variation of the ac photocurrent I.sub.p in nA with the modulation frequency of the incident modulated light beam 132 in Hz. Consequently, the capacitive device 134 according to this exemplary embodiment exhibits a strong non-linear behavior of the extracted ac photocurrent I.sub.p with the variation of the size of the impinging light spot, denoted as the FIP effect.
[0324] In contrast to known FIP devices based on photodiodes or photoconductors, where a decrease of the FIP signal with increasing modulation frequency of the incident light beam 132 can typically be observed, the frequency response of the FIP signal as recorded according to FIG. 3D for the example of FIG. 3B firstly increases with increasing modulation frequency until a maximum value for the FIP signal is achieved at in a region around 1 kHz to 5 kHz whereupon the FIP signal decreases for further increasing modulation frequencies of the incident light beam 132. The initial increase of the FIP signal with increasing modulation frequencies of the incident light beam 132 can be attributed to a capacitive nature of the capacitive device 134 as comprised by the longitudinal optical sensor 114 according to the present invention.
[0325] Further, FIG. 3E displays a current vs. voltage characterization of the capacitive device 134 according to the example of FIG. 3B. Herein, a variation of a density j of the photocurrent I.sub.p in mA/cm.sup.2 is shown with respect to the variation of a voltage U in V as applied across the capacitive device 134. Thus, a pronounced non-linearity between an incident photon density and an ac photocurrent I.sub.p can been observed in this exemplary embodiment, while a direct current (dc) photocurrent has been found to be negligible. As mentioned above, no photocurrent I.sub.p can be detected at dc light conditions while modulated light, however, yields an appreciable photocurrent I.sub.p.
[0326] Similarly, FIG. 3F displays a comparison of the current vs. voltage characterizations for both examples according to FIGS. 3A and 3B simulated at one sun white light illumination. Herein, no appreciable dc photocurrent I.sub.p is detected at short circuit conditions, thus leading to a vanishing of the current density j, too. A parallel resistance in the example of FIG. 3A with only Ag electrodes is significantly larger (3.4 M) compared to the example of FIG. 3B with both the MoO.sub.3 charge-carrier transporting layer 182 and the Ag electrodes (0.4 M)
[0327] Further, for obtaining the experimental results as presented in FIGS. 3G to 3I the light emitting diode (LED) 140 was operated at a wavelength of 850 nm, a modulation frequency of 375 Hz, and an illumination power of 165 W. A 50 mm objective was employed at a distance of 83 cm to the LED 140. Compared to a focused state 184 in which the focus is located in the sensor region 130, a defocused state 186 was obtained by moving the LED 140 about 12.5 mm.
[0328] In particular, FIG. 3G illustrates a comparison of the variation of the alternating current (ac) photocurrent I.sub.p in nA with a distance d of the sensor region 130 to the object in mm for both examples of FIGS. 3A and 3B. Further, FIGS. 3H and 3I each display a comparison of the variation of the ac photocurrent I.sub.p in nA with the modulation frequency of the incident modulated light beam 132 in Hz for both the focused state 184 and the defocused state 186 for the example of FIG. 3A (FIG. 3H) and for the example of FIG. 3B (FIG. 3I), respectively.
[0329] Further, FIG. 3J shows the comparison of the variation of the alternating current (ac) photocurrent I.sub.p in nA with a distance d of the sensor region 130 to the object in mm for both examples of FIGS. 3A and 3B at the maximum value of the FIP signal which was achieved by operating the LED 140 at wavelength of 850 nm and a modulation frequency of 3777 Hz.
[0330] Further, for obtaining the experimental results as presented in FIGS. 3K to 3M the LED 140 was operated at a wavelength of 1550 nm, a modulation frequency of 375 Hz, and an unknown illumination power. A 50 mm objective was employed at a distance of 20.5 cm to the LED 140. Again, then defocused state 186 was obtained by moving the LED 140 about 12.5 mm with regard to the focused state 184.
[0331] In particular, FIG. 3K illustrates a comparison of the variation of the alternating current (ac) photocurrent I.sub.p in nA with a distance d of the sensor region 130 to the object in mm for both examples of FIGS. 3A and 3B. Further, FIGS. 3L and 3M each display a comparison of the variation of the ac photocurrent I.sub.p in nA with the modulation frequency of the incident modulated light beam 132 in Hz for both the focused state 184 and the defocused state 186 for the example of FIG. 3A (FIG. 3L) and for the example of FIG. 3B (FIG. 3M), respectively.
[0332] Further, FIG. 3N shows the comparison of the variation of the alternating current (ac) photocurrent I.sub.p in nA with a distance d of the sensor region 130 to the object in mm for both examples of FIGS. 3A and 3B at the maximum value of the FIP signal which was achieved by operating the LED 140 at wavelength of 1550 nm and a modulation frequency of 3777 Hz.
[0333] FIG. 4A illustrates a cross section of a second preferred exemplary embodiment of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a schematic fashion while FIGS. 4B to 4G provide experimental results obtained for the capacitive device 134 exhibiting an arrangement according to this embodiment.
[0334] The second exemplary embodiment of the capacitive device 134 according to FIG. 4A again comprises the glass substrate 172 which is coated by the layer of the transparent conductive oxide (TCO) 168 comprising indium-doped tin oxide (ITO). As mentioned above, a layer of fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), or of another TCO may alternatively be used as the transparent conductive oxide 168 coating the glass substrate 172 or, as an alternative, a quartz substrate or an optically transparent and electrically insulating polymer, such as polyethylene terephthalate (PET).
[0335] In contrast to the exemplary embodiment of FIGS. 3A and 3B, the photosensitive layer 180 in the second exemplary embodiment of FIG. 4A exhibits a different arrangement having a more complex structure. Herein, the photosensitive layer 180 comprises two individual photoconductive layers 188, 188, wherein a boundary between the two individual photoconductive layers 188, 188 forms a junction 190 which is adapted to generate the charge carriers upon illumination by the incident light beam 132. As shown in FIG. 4A, the two individual photo-conductive layers 188, 188 comprise cadmium sulfide (CdS) and cadmium telluride (CdTe) which have been provided by a deposition at approximately 300 C. However, other kinds of suitable photoconductive materials may also be used for the purposes of the present invention.
[0336] In order to facilitate the transport of the charge carriers generated in the photosensitive layer 180 from their place of generation within the junction 190 provided by the two individual photoconductive layers 188, 188 to the adjacent electrode, which here exemplarily comprises the transparent conductive oxide (TCO) 168 indium-doped tin oxide (ITO), the capacitive device 134 in the embodiment of FIG. 4A further comprises a charge-carrier transporting layer 182 which is particularly configured for this purpose. Since it may be advantageous that the charge-carrier transporting layer 182 in the embodiment as depicted in FIG. 4A may at least be partially transparent to the incident light beam 132 in order to allow the incident light beam 132 to impinge the junction 190, the charge-carrier transporting layer 182 may, thus, comprise a transparent material, preferably a transparent oxide, in particular tin dioxide (SnO.sub.2). During preparation, the SnO.sub.2 deposited onto the ITO layer has been activated by a treatment with cadmium chloride (CdCl.sub.2) at approximately 400 C. for about 45 min. However other kinds of materials which exhibit suitable charge-carrier transporting and optical properties as well as other production methods for generating this layer may also be feasible.
[0337] Further, the capacitive device 134 in the second exemplary embodiment also comprises a thin insulating aluminum oxide (Al.sub.2O.sub.3) layer having a thickness of approximately 80 nm as the insulating layer 178, wherein the Al.sub.2O.sub.3 layer has been provided in this example by applying low temperature atomic layer deposition (ALD) at a temperature of around 60 C. directly onto the CdS layer.
[0338] Further, the capacitive device 134 in this embodiment comprises the metal electrode 176 as the second electrode 174. Herein, a thin layer of approximately 200 nm silver (Ag) was deposited on the thin insulating aluminum oxide (Al.sub.2O.sub.3) layer photosensitive layer 180. As mentioned above, platinum (Pt), gold (Au), or aluminum (Al) could also be used here as alternative electrode materials in the second electrode 174.
[0339] As a result, the capacitive device 134 of this embodiment constitutes a metal-insulator-semiconductor (MIS) device 192 which comprises the Ag electrode 176, the thin insulating Al.sub.2O.sub.3 (ALD) layer 178 and the CdTe photosensitive layer 180. As shown in FIGS. 4B to 4G, a strong non-linear behavior of the ac photocurrent I.sub.p with a variation of the size of the impinging light spot can be observed, thus providing clear evidence of an occurrence of the FIP effect in the capacitive device 134 according to this second exemplary embodiment.
[0340] FIGS. 4B to 4E each illustrate the photocurrent I.sub.p in nA of the detector 110 comprising the capacitive device 134 of this second embodiment as a function of distance d of the sensor region 130 to the object 112 in mm, wherein each curve represents the variation of the photocurrent I.sub.p for a preset current as indicated in the corresponding Figure, wherein each preset current is used to operate the LED 140 being provided in order to illuminate the photosensitive layer 180 of the corresponding the capacitive device 134. The modulation frequency for the incident modulated light beam 132 was chosen as 375 Hz in all of FIGS. 4B to 4E. While a wavelength of 660 nm was provided by the LED 140 to record the curves as displayed in FIGS. 4B and 4C, the LED 140 provided a wavelength of 850 nm in order to acquire the curves as shown in FIGS. 4 D and 4E. Whereas the curves as displayed in FIGS. 4B and 4D are recorded by using a bare LED 140, a diffuser disk was employed for recording the curves as shown in FIGS. 4 C and 4E, respectively. Herein, the diffuser disk is adapted to allow having a larger light spot in the sensor region 130 at lower illumination power, thus, resulting in a less concentrated illumination when imaged onto the sensor region 130.
[0341] Further, FIGS. 4F and 4G each display a comparison of the variation of the ac photocurrent I.sub.p, in A with the modulation frequency of the incident modulated light beam 132 in Hz between the focused state 184 and the defocused state 186. Herein, the defocused state 186 was obtained by moving the LED 140, which was located about 82 cm away from a 50 mm objective in the focused state 184, about 12 mm from the focus. Herein, the curves in FIG. 4F are recorded at the wavelength of 660 nm while the curves in FIG. 4G are recorded at the wavelength of 850 nm.
[0342] FIGS. 5A and 5B each illustrate a cross section of a preferred example of a third exemplary embodiment of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a schematic fashion while FIGS. 5C to 5I provide experimental results obtained for the capacitive device 134 exhibiting an arrangement according to this embodiment in comparison to a solar cell arrangement using similar materials having, however, a divergent setup.
[0343] In both examples of this particular embodiment, the metal electrode 176 is provided as intransparent molybdenum (Mo) electrode which may be deposited on a substrate 170, wherein the substrate can exhibit intransparent optical properties, too. However, it may also be feasible to employ a transparent substrate, such as a glass substrate as described elsewhere in this document.
[0344] Similar to the second exemplary embodiment of the capacitive device 134 as depicted in FIG. 4A, the third exemplary embodiment of FIGS. 5A and 5B comprises the junction 190 which is formed by the boundary between the two individual photoconductive layers 188, 188 comprising here a layer of cadmium sulfide (CdS) and a layer of copper zinc tin sulfide (CZTS), respectively. Thus, the CZTS layer can be considered as replacing the CdTe of the embodiment according to FIG. 4A. As an alternative to CZTS, copper zinc tin selenide (CZTSe), the corresponding sulfur-selenium alloy CZTSSe, or a further quaternary chalcogenide photo-conductive I.sub.2-II-IV-VI.sub.4 compound can also be applied for this purpose. Further alternatives may include copper indium gallium selenide (CIGS) or other chalcogenide photoconductors which are known as thin-film solar cell absorber layers.
[0345] Similar to the second exemplary embodiment of the capacitive device 134 according to FIG. 4A, a thin Al.sub.2O.sub.3 layer, which may, preferably, have a thickness of approximately 70 mm, can, as schematically depicted in FIG. 5A, again be used as the insulator layer 178. FIG. 5B shows an alternative for the insulator layer 178, in which a double layer comprising an individual ZrO.sub.2 layer and an individual Al.sub.2O.sub.3 layer provided on top of each other were applied. Herein, each of both individual layers exhibited a thickness of approximately 70 mm. In addition, both individual layers exhibit a high transparency, thus, allowing the incident light beam 132 to reach the junction 190 within the photosensitive layer 180. However, other kinds of combinations of individual layers used as the insulator layer 178 and thicknesses thereof may also be feasible.
[0346] The capacitive devices 134 according to FIGS. 5A and 5B may be finalized by a deposition of ITO as the first electrode 166 which, in contrast to the embodiments of FIG. 2A, 2B, 3A, 3B, 4A, 6A, 7A, 7B, 10A, 10B or 10C is designed as a top contact electrode in this particular embodiment. However, the first electrode 166 in third exemplary embodiment of the capacitive device 134 according to FIGS. 5A and 5B can also be provided as a bottom contact electrode while the first electrode 166 in the other embodiments may also be designated as a top contact electrode provided that this arrangement may still capable of allowing the incident light beam 132 to reach the photosensitive layer 180.
[0347] As can be derived from FIGS. 5C to 5I, the detector 110 comprising the capacitive device 134 of the third embodiment according to both examples of FIGS. 5A and 5B, exhibits a strong non-linear behavior of the ac photocurrent I.sub.p with a variation of a size of the impinging light spot, hence producing the FiP effect. As particularly shown in FIGS. 5C to 5G, the FiP effect is significant even at low light intensities of the incident light beam 132. In contrast hereto, a CZTS-based solar cell 194 being provided in form of a photodiode for optimized photovoltaic performance was proved to show a negative FiP effect, predominantly at rather large light intensities. Herein, a particular difference between the capacitive device 134 of the third embodiment and the solar cell 194 as a solar cell reference device consists in that the capacitive device 134 comprises the insulating layer 178 while the insulating layer 178 is absent in the solar cell 194. In addition, the FiP effect in the solar cell 194 may only be observable in a narrow range around the focus of the detector 110. The data in FIGS. 5C to 5I was obtained with red light of a wavelength of 660 nm provided by the bare LED 140 focused with a 50 mm objective.
[0348] FIG. 5C illustrates that an appreciable FiP effect could be observed in the capacitive device 134 of the third embodiment, even at a low intensity of the incident light beam 132 of 0.36 W, while, in contrast hereto, the CZTS-based solar cell 194 did not exhibit an appreciable FiP effect at the same intensity. Herein, the current level applied to the LED 140 was comparable for both the capacitive device 134 and the reference solar cell 194.
[0349] FIGS. 5D and 5E show that, with increasing intensity of the incident light beam 132 to 20.6 W, the FiP response becomes broader and hence the discrepancy between the current levels of the capacitive device 134 and the CZTS-based solar cell 194 used as a reference widens. Herein, the photocurrent I.sub.p response at 375 Hz is provided as absolute numbers in FIG. 5D and as normalized to the maximum value in FIG. 5E, respectively.
[0350] FIGS. 5F and 5G illustrate that the capacitive device 134 shows very low photo-current levels at high intensities of the incident light beam 132 at 1.54 mW, probably owing to an extremely broad negative FiP. At the same intensity level, the negative FiP effect in the CZTS-based solar cell 194 provides a significant response as well. The photocurrent I.sub.p response at 375 Hz is provided as absolute numbers in FIG. 5F and as normalized to the maximum value in FIG. 5G, respectively.
[0351] The spectral response of the modulated photocurrent I.sub.p at high intensities of the incident light beam 132 at 1.54 mW is provided as absolute values in FIG. 5H as well as normalized to the maximum value in FIG. 51. While the CZTS-based solar cell 194 shows a broad and almost constant frequency response between ca. 10 Hz and ca. 10 kHz, the capacitive device 134 exhibits a pronounced peak above 1 kHz demonstrating its capacitive behavior.
[0352] FIG. 6A illustrates a cross section of a preferred example of a forth exemplary embodiment of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a schematic fashion while FIGS. 6B to 6E provide experimental results obtained for the capacitive device 134 exhibiting this kind of arrangement.
[0353] According to FIG. 6A this example of the forth exemplary embodiment of the capacitive device 134 exhibits an arrangement in which the FTO electrode 168 located on the glass substrate 172 acts as the first electrode 166 while the second electrode 174 comprises a gold (Au) electrode 176 which is deposited on the approximately 90 nm thick insulating layer 178 of Al.sub.2O.sub.3 obtained by low temperature atomic layer deposition (ALD) at the temperature of around 60 C.
[0354] In further contrast to the other embodiments as presented herein, the photosensitive layer 180 comprises here a semiconductor absorber layer 196, in particular, a hydrogenated amorphous silicon (a-Si:H) absorber layer having a thickness of approximately 500 nm. As a result, the capacitive device 134 of this embodiment, thus, again constitutes the metal-insulator-semiconductor (MIS) device 192 which comprises the Au electrode 176, the thin insulating Al.sub.2O.sub.3 (ALD) layer 178 and the photosensitive layer 180 of the amorphous Silicon (a-Si:H). As particularly shown in FIGS. 6B to 6E, this particular embodiment of the capacitive device 134, again, shows a strong non-linear behavior of the ac photocurrent I.sub.p with a variation of a size of the impinging light spot, hence providing evidence of the FIP effect. The data in FIGS. 6B to 6E were recorded by using a 50 mm objective, whereby a distance between the LED 140 to the objective was adjusted to 0.8 m.
[0355] FIGS. 6B and 6C illustrate the occurrence of the FiP effect in a sample of the detector 110 comprising the forth embodiment of the capacitive device 134 by displaying a strong non-linear behavior of the ac photocurrent I.sub.p with a variation of a size of the impinging light spot. For the purpose of characterization, the LED 140 emitted at a wavelength of 660 nm at 375 Hz modulation frequency, the duty cycle hereby amounting to 50%. While FIG. 6B shows the results with application of a diffuser disk having a diameter of 15 mm installed in front of the LED 140, FIG. 6C displays the corresponding results obtained by using the bare LED 140 without applying the diffuser disk.
[0356] FIGS. 6D and 6E illustrate a difference in the photoresponse at the wavelength of 660 nm as a function of the modulation frequency of the incident modulated light beam 132 between the focused state 184 obtained by using the above-mentioned 50 mm objective and the defocused state 186, wherein the light spot, however, still assumed more than 50% of the sensor region 130. While in FIG. 6D the diffuser disk having the diameter of 15 mm was used and the illumination power, thus, amounted to 4.23 W, in FIG. 6E no diffuser disk was applied, resulting in the illumination power of approximately 459 W.
[0357] FIGS. 7A and 7B each illustrate a cross section of a preferred example of a fifth exemplary embodiment of the capacitive device 134, in particular for use in the longitudinal optical sensor 114, in a schematic fashion while FIGS. 7C to 7I provide experimental results obtained for the capacitive device 134 exhibiting an arrangement according to this embodiment.
[0358] Herein, the example of the capacitive device 134 as depicted in FIG. 7A is similar to the example of the capacitive device 134 as shown in FIG. 3B. Accordingly, the ITO electrode 168 located on the glass substrate 172 acts as the first electrode 166, on which a thin insulating layer 178 of Al.sub.2O.sub.3 obtained by atomic layer deposition (ALD) at the temperature of around 200 C. is deposited, such as by applying 300 deposition cycles. Further, the second electrode 174 comprises an approximately 200 nm thick silver (Ag) electrode 176 which is deposited on the charge-carrier transporting layer 182, in particular on the above-described hole transporting layer of molybdenum oxide (MoO.sub.3) exhibiting a thickness of approximately 15 nm MoO.sub.3. For possible material alternatives reference may be made to the description of FIG. 3B.
[0359] However, in contrast to the example of FIG. 3B, the photosensitive layer 180 according to fifth exemplary embodiment of the capacitive device 134 has an organic photosensitive layer 198. Herein, the organic photosensitive layer 198, preferably, comprises at least one electron donor material and at least one electron acceptor material, especially, arranged within a single layer as an interpenetrating network of donor and acceptor domains, interfacial areas between the donor and acceptor domains, and percolation pathways connecting the domains to the electrodes, thereby generating a bulk heterojunction within the photosensitive layer 180.
[0360] In this particular embodiment, the electron donor material comprises an organic donor polymer and the electron acceptor material comprises a fullerene-based electron acceptor material. In both FIGS. 7A and 7B, the organic donor polymer used is poly(3-hexylthiophene-2,5-diyl) (P3HT) while the fullerene-based electron acceptor material [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). However, as mentioned above in more detail, other kinds of electron donor materials and/or electron acceptor materials may also be feasible for the organic photosensitive layer 198 to be used in the capacitive device 134 according to the present invention. In particular, 50 mg/ml P3HT and 32 mg/ml PCBM were dissolved in chlorobenzene and cast by applying a spin rotation frequency of approximately 3000 rpm, whereby a solution-processed polymer:fullerene film was obtained on top of the insulating Al.sub.2O.sub.3 (ALD) layer 178.
[0361] As an alternative, FIG. 7B illustrates a further example of the fifth exemplary embodiment of the capacitive device 134 in which, instead of using the insulating Al.sub.2O.sub.3 (ALD) layer 178, a thick layer comprising a film of polyethylenimine ethoxylate (PEIE) having a thickness of approximately 500 nm, was applied. As further alternatives, the insulating layer 178 may be selected from a film comprising at least one transparent organic dielectric material, in particular, selected from polyethylenimine (PEI), 2,9-dimethyl-4,7-diphenylphenanthroline (BCP), poly-(vinylalcohol) (PVA), poly(methylmethacrylate) (PMMA), tris-(8-hydroxyquinoline)aluminum (Alq3), or (3-(4-bi-phenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole) (TAZ).
[0362] FIGS. 7C and 7E illustrate the occurrence of the FiP effect in a sample of the detector 110 comprising the embodiment of the capacitive device 134 as displayed in FIG. 7A by displaying a strong non-linear behavior of the ac photocurrent I.sub.p with a variation of a size of the impinging light spot. Herein, each curve represents the variation of the photocurrent I.sub.p, for a preset current as indicated in the corresponding Figure, wherein each preset current is used to operate the LED 140. As a result, a negative FiP response is always obtained, even at low light intensities. Further, FIGS. 7D and 7F display the ac photocurrent I.sub.p with the variation of the modulation frequency of the incident modulated light beam 132 in the focused state 184 and in the defocused state 186, the latter obtained by moving the LED 140 about 12.5 mm off focus. Further, FIG. 7G shows the I-V characteristic of the capacitive device 134 illustrating the current density j which reveals that only a leakage current may be observed since the dc current is suppressed by at least two orders of magnitude compared to a known photodiode configuration.
[0363] For the purpose of characterization, the LED 140 used here emitted at a wavelength of 530 nm at 375 Hz modulation frequency. While FIGS. 7C and 7D show the results obtained by using the bare LED 140 without applying the diffuser disk, thus, providing the illumination power of 165 W, FIGS. 7E and 7F display the corresponding results with application of a diffuser disk installed in front of the LED 140, thus, reducing the illumination power to 1.26 W. Herein, the diffuser disk is adapted to allow having a larger light spot in the sensor region 130 at lower illumination power, thus, resulting in a less concentrated illumination when imaged onto the sensor region 130.
[0364] Further FIGS. 7H and 71 illustrate the photocurrent as a function of the distance of the sensor region 130 to the object and as a function of the modulation frequency of the incident modulated light beam 132, respectively, for a further sample of the detector 110 comprising the embodiment of the capacitive device 134 as displayed in FIG. 7A which was recorded at a wavelength of 850 nm for the incident light beam 132.
[0365] FIG. 8 shows an exemplary embodiment of a detector system 200, comprising at least one optical detector 110, such as the optical detector 110 comprising the capacitive device 134 as disclosed in one or more of the embodiments shown in FIG. 2A, 2B, 3A, 3B, 4A, 5A, 5B, 6A, 7A or 7B or a combination thereof. Herein, the optical detector 110 may be employed as a camera 202, specifically for 3D imaging, which may be made for acquiring images and/or image sequences, such as digital video clips. Further, FIG. 8 shows an exemplary embodiment of a human-machine interface 204, which comprises the at least one detector 110 and/or the at least one detector system 200, and, further, an exemplary embodiment of an entertainment device 206 comprising the human-machine interface 204. FIG. 8 further shows an embodiment of a tracking system 208 adapted for tracking a position of at least one object 112, which comprises the detector 110 and/or the detector system 200.
[0366] With regard to the optical detector 110 and to the detector system 200, reference may be made to the full disclosure of this application. Basically, all potential embodiments of the detector 110 may also be embodied in the embodiment shown in FIG. 8. The evaluation device may be connected to each of the at least two longitudinal optical sensors, in particular, by the signal leads 154. As described above, one or more longitudinal optical sensors 114 are used in order to provide the longitudinal sensor signals. The evaluation device 150 may further be connected to the at least one optional transversal optical sensor 160, in particular, by the signal leads 154. By way of example, the signal leads 154 may be provided and/or one or more interfaces, which may be wireless interfaces and/or wire-bound interfaces. Further, the signal leads 154 may comprise one or more drivers and/or one or more measurement devices for generating sensor signals and/or for modifying sensor signals. Further, again, the at least one transfer device 120 may be provided, in particular as the refractive lens 122 or convex mirror. The optical detector 110 may further comprise the at least one housing 118 which, as an example, may encase one or more of components.
[0367] Further, the evaluation device 150 may fully or partially be integrated into the optical sensors and/or into other components of the optical detector 110. The evaluation device 150 may also be enclosed into the housing 118 and/or into a separate housing. The evaluation device 150 may comprise one or more electronic devices and/or one or more software components, in order to evaluate the sensor signals, which are symbolically denoted by the longitudinal evaluation unit 152 (denoted by z) and a transversal evaluation unit 162 (denoted by x y). By combining results derived by these evolution units, a position information 164, preferably a three-dimensional position information, may be generated (denoted by x y z).
[0368] The at least one optional transversal optical sensor 160 may, preferably, be provided in a setup as illustrated below in the exemplary embodiment of FIG. 9. However, other setups may also be feasible, such as by using a known PSD, in particular a photodetector as disclosed e.g. in WO 2012/110924 A1 or WO 2014/097181 A1 or a photoconductor as disclosed e.g. in WO 2016/120392 A1. However, other setups of the transversal optical sensor 160 may also be feasible.
[0369] Further, the optical detector 110 and/or to the detector system 200 may comprise an imaging device 210 which may be configured in various ways. Thus, as depicted in FIG. 8, the imaging device can for example be part of the detector 110 within the detector housing 118. Herein, the imaging device signal may be transmitted by one or more signal leads 154 to the evaluation device 150 of the detector 110. Alternatively, the imaging device 210 may be separately located outside the detector housing 118. The imaging device 210 may be fully or partially transparent or intransparent. The imaging device 210 may be or may comprise an organic imaging device or an inorganic imaging device. Preferably, the imaging device 210 may comprise at least one matrix of pixels, wherein the matrix of pixels may particularly be selected from the group consisting of: an inorganic semiconductor sensor device such as a CCD chip and/or a CMOS chip; an organic semiconductor sensor device.
[0370] In the exemplary embodiment as shown in FIG. 8, the object 112 to be detected, as an example, may be designed as an article of sports equipment and/or may form a control element 212, the position and/or orientation of which may be manipulated by a user 214. Thus, generally, in the embodiment shown in FIG. 8 or in any other embodiment of the detector system 200, the human-machine interface 204, the entertainment device 206 or the tracking system 208, the object 112 itself may be part of the named devices and, specifically, may comprise the at least one control element 212, specifically, wherein the at least one control element 212 has one or more beacon devices 216, wherein a position and/or orientation of the control element 212 preferably may be manipulated by user 214. As an example, the object 112 may be or may comprise one or more of a bat, a racket, a club or any other article of sports equipment and/or fake sports equipment. Other types of objects 112 are possible. Further, the user 214 may be considered as the object 112, the position of which shall be detected. As an example, the user 214 may carry one or more of the beacon devices 216 attached directly or indirectly to his or her body.
[0371] The optical detector 110 may be adapted to determine at least one item on a longitudinal position of one or more of the beacon devices 216 and, optionally, at least one item of information regarding a transversal position thereof, and/or at least one other item of information regarding the longitudinal position of the object 112 and, optionally, at least one item of information regarding a transversal position of the object 112. Particularly, the optical detector 110 may be adapted for identifying colors and/or for imaging the object 112, such as different colors of the object 112, more particularly, the color of the beacon devices 216 which might comprise different colors. The opening in the housing, which, preferably, may be located concentrically with regard to the optical axis of the detector 110, may preferably define a direction of a view of the optical detector 110.
[0372] The optical detector 110 may be adapted for determining the position of the at least one object 112. Additionally, the optical detector 110, specifically an embodiment including the camera 202, may be adapted for acquiring at least one image of the object 112, preferably a 3D-image. As outlined above, the determination of a position of the object 112 and/or a part thereof by using the optical detector 110 and/or the detector system 200 may be used for providing a human-machine interface 204, in order to provide at least one item of information to a machine 218. In the embodiments schematically depicted in FIG. 8, the machine 218 may be or may comprise at least one computer and/or a computer system comprising the data processing device 158. Other embodiments are feasible. The evaluation device 150 may be a computer 156 and/or may comprise a computer 156 and/or may fully or partially be embodied as a separate data processing device 158 and/or may fully or partially be integrated into the machine 218, particularly the computer. The same holds true for a track controller 220 of the tracking system 208, which may fully or partially form a part of the evaluation device 150 and/or the machine 218.
[0373] Similarly, as outlined above, the human-machine interface 204 may form part of the entertainment device 206. Thus, by means of the user 214 functioning as the object 112 and/or by means of the user 214 handling the object 112 and/or the control element 212 functioning as the object 112, the user 214 may input at least one item of information, such as at least one control command, into the machine 218, particularly the separate data processing device 158, thereby varying the entertainment function, such as controlling the course of a computer game.
[0374] FIG. 9 illustrates a cross section of a preferred example of a sixth exemplary embodiment of the capacitive device 134, in particular for use in the transversal optical sensor 160, in a schematic fashion while FIGS. 9B and 9C provide experimental results obtained for the capacitive device 134 exhibiting an arrangement according to this embodiment.
[0375] Herein, the example of the capacitive device 134 as depicted in FIG. 9A is similar to the example of the capacitive device 134 as shown in FIG. 3A. Accordingly, the ITO electrode 168 located on the glass substrate 172 acts as the first electrode 166, on which a thin insulating layer 178 of Al.sub.2O.sub.3 obtained by atomic layer deposition (ALD) is deposited. Further, the capacitive device 134 comprises a layer of nanoparticulate lead sulfide (np-PbS) which acts as the photosensitive layer 180. For further details and possible material alternatives for the first electrode 166, the glass substrate 172, the insulating layer 178, and the photosensitive layer 180, reference may be made to the description of FIGS. 3A, 3B, 4A, 5A, 5B, 6A, 7A and 7B.
[0376] However, in contrast to the example of FIG. 3B, instead of a high electrical conductivity metal layer 176 the sixth exemplary embodiment of the capacitive device 134 has an electrode layer 222 having a low electrical conductivity which is used here as the second electrode 174. In particular, the electrode layer 222 may exhibit a sheet resistance of 100 /sq to 20 000 /sq, preferably of 100 /sq to 10 000 /sq, more preferred 125 of /sq to 1000 /sq, specifically of 150 of /sq to 500 /sq, thus, allowing determining at which position the charge was actually generated within the photosensitive layer 180 and concluding the position at which the incident light beam impinged the sensor region 130. As a result of the sheet resistance being in the indicated range, the capacitive device 134, in which the second electrode 174 may further be equipped with the at least one split electrode 224, may act as the transversal detector 160. Consequently, the capacitive device 134 as depicted in FIG. 9A shows an in-plane sensitivity with respect to the position of the impinging light beam 132 by using a similar approach as in a known position-sensitive device (PSD). This feature can be employed for this purpose by using modulated light which may be capable of inducing an ac current through the insulator layer 178.
[0377] Preferably, the electrode layer 222 of low electrical conductivity may comprise a layer of a transparent electrically conducting organic polymer which may be suitable for this purpose. In particular, poly(3,4-ethylenedioxy-thiophene) (PEDOT) or a dispersion of PEDOT and a polystyrene sulfonic acid (PEDOT:PSS) may be selected as the transparent electrically conducting polymer. On the other hand, since the first electrode 166 may already be at least partially transparent, a larger variety of different materials, including optically intransparent materials, may be employed for this purpose.
[0378] FIG. 9B shows experimental results which demonstrate the applicability of the transversal optical sensor 160 a schematically illustrated in FIG. 9A for this purpose. Herein, the transversal optical sensor 160 which comprises a layer of nanoparticulate lead sulfide (np-PbS) as the photosensitive layer 180, has been illuminated by an near-infrared (NIR) laser diode which is adapted to emit a wavelength of 850 nm with a power of 1 mW at an applied voltage of 5 V. Further, a modulation frequency of 375 Hz for NIR the laser diode has been used. Herein, a distance between the laser diode and the sensor region 130 was 20 cm.
[0379] FIG. 9B schematically illustrates the sensor region 130 of the transversal optical sensor 160 in an x-direction and a y-direction. Herein, for a number of measurement point positions 226 as determined by application of the evaluation device 150 of the detector 110 according to the present invention have been compared with actual positions 228 which have been available by other kinds of methods, such as by employing geometrical considerations in using a known set-up of the transversal optical sensor 160.
[0380] In order to determine a position 226 of a measurement point by application of the transversal optical sensor 160, the following procedure may be used. By way of example (not depicted here), a split electrode 224 may be applied. In particular, the split electrode 224 may comprise partial electrodes, in particular four partial electrodes which may, for example, be located on top of four rims of the second electrode 174, wherein the second electrode 174 may exhibit a square or a rectangular form, may be employed. However, other kinds of arrangements may also be feasible.
[0381] Herein, by generating charges in the photosensitive layer 180, ac electrode currents may be obtained, which, in each case, may be denoted by i1 to i4. As used herein, electrode currents i1, i2 may denote ac electrode currents through the partial electrodes being located in y-direction while electrode currents i3, i4 may denote ac electrode currents through the partial electrodes which are located in x-direction. The electrode currents may be measured by one or more appropriate electrode measurement devices in a simultaneous or a sequential fashion. By evaluating the electrode currents, the desired x- and y-coordinates of the position 226 of the measurement point under investigation, i.e. x.sub.0 and y.sub.0, may be determined. Thus, the following equations may be used:
[00001]
[0382] Herein, f might be an arbitrary known function, such as a simple multiplication of the quotient of the currents with a known stretch factor and/or an addition of an offset. Thus, generally, the electrode currents i1 to i4 might provide transversal sensor signals generated by the transversal optical sensor 114, whereas the evaluation device 140 might be adapted to generate information on a transversal position, such as at least one x-coordinate and/or at least one y-coordinate, by transforming the transversal sensor signals by using a predetermined or determinable transformation algorithm and/or a known relationship.
[0383] The results as shown in FIG. 9B demonstrate that for the number of the measurement points as presented there, the positions 226 as determined by the application of the transversal optical sensor 160 according to the sixth embodiment of the present invention are reasonably comparable with the actual positions 228 as recorded by another kind of method.
[0384] As already mentioned above, the transversal optical sensor 160 according to the sixth embodiment of the present invention may concurrently be employed as a longitudinal optical sensor 114 which may, additionally, be adapted for determining a z-position. For this purpose, a sum of the electrode currents i1, i2 through the partial electrodes located in y-direction and of the electrode currents i3, i4 through the partial electrodes located in x-direction may be used in a preferred embodiment, wherein the electrode currents may be measured by one or more appropriate electrode measurement devices in a simultaneous or a sequential fashion, for determining the z-coordinate. By evaluating these electrode currents, the desired z-coordinate of the position 226 of the measurement point under investigation, i.e. z.sub.0, may be determined by using the following Equation:
z.sub.0=f(i.sub.1+i.sub.2+i.sub.3+i.sub.4)
[0385] For further details with respect to evaluating electrode currents in order to obtain the desired z-coordinate reference may be made to WO 2012/110924 A1 or WO 2014/097181 A1.
[0386] FIG. 9C shows a segment of FIG. 9B covering a center 230 of the sensor region 130. As a result, FIG. 9C demonstrates that excellent correlation between the measurement point positions 226 and the actual positions 228 as otherwise determined could be observed, in particular within the center 230 of the sensor region 130. Deviations towards the edges 232 of the sensor region 130 which can be observed as shown in FIG. 9B behave as expected for this type of device and may be remedied by a suitable correction algorithm.
[0387] FIGS. 10A to 10C illustrate cross sections of preferred examples of a seventh exemplary embodiment of the capacitive device 134, wherein the photosensitive layer 180 of the capacitive device 134 is or comprises at least one organic photosensitive layer 198, wherein the donor material and the acceptor material in the organic photosensitive layer 198 is arranged in form of at least two individual layers each comprising one of the donor material and of the acceptor material.
[0388] As schematically depicted in FIGS. 10A and 10B, the capacitive device 134, again, comprises the layer of the transparent conductive oxide (TCO) 168 as the first electrode 166 and the metal electrode 174 as the second electrode 174, between which the insulating layer 178 and the photosensitive layer 180 are provided. For reasons of convenience, the insulating layer 178 can be deposited directly onto a substrate comprising a conductive coating and being suited as the first electrode 166. However, according to this particular example of the seventh exemplary embodiment, the organic photosensitive layer 198, in particular contrast to the embodiments of FIGS. 7A and 7B, has a donor material layer 234 and an acceptor material layer 236 which are arranged as two individual layers stacked on top of each other. In the particular embodiments of FIGS. 10A and 10B, the donor material layer 234 and the acceptor material layer 236 are separated by the junction 190, which here forms a heterojunction due to the different kinds of materials. Hence, two different kinds of layer stacks as illustrated in in FIGS. 10A and 10B are feasible which are adapted in order to provide the capacitive device 134 while maintaining an efficient extraction of one type of charge carriers.
[0389] A comparison between the examples of FIGS. 10A and 10B reveals that both examples differ by their respective arrangement of the donor material layer 234 and the acceptor material layer 236 with respect to the configuration of the electrode, in particular, with regard to the second electrode 174. While in the example of FIG. 10A the acceptor material layer 236 is being placed adjacently to the second electrode 174, only separated by the charge-carrier extracting layer 182, in the example of FIG. 10B the donor material layer 234 is being placed adjacently to the second electrode 174, again, only separated by the charge-carrier extracting layer 182. In order to be capable of extracting and transporting the corresponding charges as provided by the adjacent charge-carrier material, the charge-carrier extracting layer 182 in the example of FIG. 10A is, thus, adapted as an electron extracting layer 238 while the charge-carrier extracting layer 182 in the example of Figure B is, consequently, adapted as a hole extracting layer 240.
[0390] FIG. 10C illustrates a further example based on the embodiment as depicted in FIG. 10B. Herein, the same kind of layers is used in the same type of arrangement as shown in FIG. 10B, wherein, however, the donor material layer 234 and the acceptor material layer 236 are comprised in a single photosensitive layer 180, whereby, similar to the embodiments of FIGS. 7A and 7B, a bulk heterojunction is generated within this kind of photosensitive layer 180. In addition, further layers are introduced into the capacitive device 134 for increasing its function. In particular, a further n-doped acceptor layer 242 and a further electron extraction layer 238 are introduced between the insulating layer 178 and the acceptor material layer 236 while a p-doped extraction layer 244, wherein a dopant is provided by an additional p-dopant layer 246, is introduced between the hole extracting layer 240 and the second electrode 174. Introducing the further a further n-doped acceptor layer 242 or, depending on the particular arrangement of the capacitive device, alternatively an additional p-doped acceptor layer may be used for adjusting a distance from the ITO layer 168 to the reflecting second electrode 174, in particular, in order to improve a matching of a phase of the incident light beam 132 and of a light beam being reflected at the second electrode 174, thus, optimizing the performance of the capacitive layer 134 with regard to the power of the illumination within the organic photosensitive layer 198.
[0391] More particular, the mentioned layers in the exemplary capacitive device 134 of FIG. 10C, may, in an order starting from the bottom to the top of the capacitive device 134 as depicted in FIG. 10C, preferably, comprise the following materials, each forming a respective layer: [0392] a layer of indium-doped tin oxide (ITO) as the first electrode 166, such as described above; [0393] an Al.sub.2O.sub.3 layer, preferably provided by ALD, in particular processed at approx. 200 C., having a preferred thickness of ca. 70 nm, as the insulating layer 178, such as described above; [0394] an n-C60 layer, i.e. an n-doped buckminsterfullerene layer, treated with an n-dopant, in particular with 10% NDN-26, processed at approx. 140 C., preferably having a thickness of ca. 15 nm, as the n-doped acceptor layer 242; [0395] a C60 layer, i.e. an undoped buckminsterfullerene layer, processed at approx. 400 C., preferably having a thickness of ca. 10 nm, as the electron extraction layer 238; [0396] a F4ZnPc:C60 layer, i.e. a layer comprising a 1:1 blend of a fluorinated zinc phthalo-cyanine derivative (F4ZnPc) and buckminsterfullerene, processed at approx. 335 C. and deposited on a substrate having a temperature of 110 C., preferably exhibiting a thickness of ca. 70 nm as the single photosensitive layer 180 consolidating the donor material layer 234 and the acceptor material layer 236 in a single layer exhibiting a bulk heterojunction; [0397] a layer of undoped 9,9-bis[4-(N,N-bis-biphenyl-4-yl-amino)phenyl]-9H-fluorene (BPAPF), preferably having a thickness of ca. 10 nm, as the hole extraction layer 240; [0398] p-BPAPF, i.e. p-doped BPAPF, treated with a p-dopant, in particular NDP-9, processed at approx. 140 C., preferably having a thickness of ca. 30-40 nm, as p-doped extraction layer 244; and [0399] an NDP-9 layer, preferably having a thickness of ca. 1-2 nm, as the additional p-dopant layer 246; and [0400] a silver (Ag) layer as the second electrode 174, such as described above.
[0401] However, other kinds of materials suited for the respective layers in the capacitive device may also be feasible. Hereby, reference may, in particular, be made to the other embodiments as described herein.
[0402] Further, N,N-diphenyl-N,N-bis(4-(N,N-bis(naphth-1-yl)-amino)-biphenyl-4-yl)-benzidine (DiNPB) may be used as an alternative for BPAPF in the hole extraction layer 240. Similarly, Bathophenantroline (BPhen) may be used as the electron extraction layer 238 in a comparable arrangement which may be based on the example of FIG. 10A.
[0403] Further, the terms NDN and NDP refer to n-side or d-side dopants, respectively, which are provided by Novaled GmbH. Thus, NDN-26 and NDP-9 refer to specific n-side or d-side dopant. However other kinds of n-dopants or -p-dopants may also be feasible, respectively.
LIST OF REFERENCE NUMBERS
[0404] 110 detector [0405] 112 object [0406] 114 longitudinal optical sensor [0407] 116 optical axis [0408] 118 housing [0409] 120 transfer device [0410] 122 refractive lens [0411] 124 opening [0412] 126 direction of view [0413] 128 coordinate system [0414] 130 sensor region [0415] 132 modulated light beam [0416] 134 capacitive device [0417] 136 illumination source [0418] 138 artificial illumination source [0419] 140 light-emitting diode [0420] 142 modulated illumination source [0421] 144 modulation device [0422] 146 first beam path [0423] 148 second beam path [0424] 150 evaluation device [0425] 152 longitudinal evaluation unit [0426] 154 signal leads [0427] 156 computer [0428] 158 data processing device [0429] 160 transversal optical sensor [0430] 162 transversal evaluation unit [0431] 164 position information [0432] 166 first electrode [0433] 168 transparent conductive oxide [0434] 170 optically transparent substrate [0435] 172 glass substrate [0436] 174 second electrode [0437] 176 metal electrode [0438] 178 insulating layer [0439] 180 photosensitive layer [0440] 182 charge-carrier transporting layer or charge-carrier extracting layer [0441] 184 focused state [0442] 186 defocused state [0443] 188, 188 individual photoconductive layer [0444] 190 junction [0445] 192 metal-insulator-semiconductor device [0446] 194 solar cell (reference device) [0447] 196 semiconductor absorber layer [0448] 198 organic photosensitive layer [0449] 200 detector system [0450] 202 camera [0451] 204 human-machine interface [0452] 206 entertainment device [0453] 208 tracking system [0454] 210 imaging device [0455] 212 control element [0456] 214 user [0457] 216 beacon device [0458] 218 machine [0459] 220 track controller [0460] 222 electrode layer [0461] 224 split electrode [0462] 226 measurement point position [0463] 228 actual position [0464] 230 center [0465] 232 edge [0466] 234 donor material layer [0467] 236 acceptor material layer [0468] 238 electron extraction layer [0469] 240 hole extraction layer [0470] 242 n-doped acceptor layer [0471] 244 p-doped hole extraction layer [0472] 246 p-dopant layer
