DETECTOR SYSTEM

Abstract

In a base element of a waveguide for a detector system at least a portion of radiation passing via the front side and incident on the diffractive element in a selection region is deflected via the diffractive element such that the deflected portion is propagated as coupled-in radiation in the base element by reflection to the out-coupling region and is incident on the associated out-coupling section of the out-coupling region. The out-coupling region couples at least a portion of the radiation out of the base element such that it is incident on the associated sensor section of the sensor unit, which continuously measures the intensity of the incident radiation and supplies the control unit. The control unit determines the distance of the object from the front side of the base element according to the measured intensity.

Claims

1-13. (canceled)

14. A detector system, comprising: a waveguide, comprising a transparent base body having a front and a rear; a display device that shows a selection region in such a way that it can be seen in a display region of the base body when the front is viewed; a sensor device comprising an assigned sensor section for the selection region; and a control device, wherein the base body includes a diffractive element in the display region and a decoupling region that is spaced apart from the display region and comprises an assigned decoupling section for the selection region, wherein at least a portion of radiation that is incident on the diffractive element in the selection region via the front is deflected via the diffractive element such that the deflected portion propagates as coupled-in radiation in the base body by reflection as far as the decoupling region and is incident on the assigned decoupling section of the decoupling region, wherein the decoupling region decouples at least a portion of the coupled-in radiation that is incident on the decoupling region from the base body such that said portion is incident on the assigned sensor section of the sensor device, which section continuously measures the intensity of the incident radiation and supplies it to the control device, and wherein the control device is configured to take the measured intensity as a basis for determining the distance of the object from the front of the base body.

15. The detector system of claim 14, wherein the diffractive element and/or the decoupling section comprises a wavelength-dependent imaging property having a longitudinal chromatic aberration, wherein the sensor device measures an intensity of the incident radiation as a function of wavelength and supplies the measured intensity to the control device, and wherein the control device takes the measured wavelength-dependent intensity as a basis for determining the distance of the object from the front of the base body.

16. The detector system of claim 15, wherein the diffractive element is a volume hologram.

17. The detector system of claim 14, wherein the diffractive element is a volume hologram.

18. The detector system of claim 14, wherein the diffractive element comprises a lens element function.

19. The detector system of claim 18, wherein the lens element function of the diffractive element is configured such that the coupled-in radiation propagates in the base body as a parallel pencil of rays.

20. The detector system of claim 14, wherein the decoupling section comprises a volume hologram.

21. The detector system of claim 14, wherein the decoupling section comprises a lens element function.

22. The detector system of claim 14, furterh comprising an illumination device that actively illuminates the object to be positioned in front of the front.

23. The detector system of claim 22, wherein the illumination device is configured to illuminate the object from the base body.

24. The detector system of claim 14: wherein the display device shows multiple selection regions such that the multiple selection regions can be seen in the display region of the base body when the front is viewed, wherein the sensor device comprises an assigned sensor section for each selection region, wherein at least a portion of radiation that is incident on the diffractive element in the display region via the front is deflected via the diffractive element on the basis of the selection region such that the deflected portion propagates as coupled-in radiation in the base body by reflection as far as the decoupling region and is incident on the assigned decoupling section of the decoupling region, wherein the decoupling region decouples at least a portion of the coupled-in radiation that is incident on it from the base body such that the portion decoupled by a decoupling section is incident on the assigned sensor section of the sensor device, which section continuously measures the intensity of the incident radiation and supplies it to the control device, and wherein the control device is configured to take a change in intensity caused by an object being positioned in front of the front of the base body and in front of a selection region of the display region as a basis for determining whether the selection region has been selected.

25. The detector system of claim 24, wherein the deflection via the diffractive element on the basis of the selection region differs by different propagation angles within the transparent base body and/or different deflected wavelengths.

26. The detector system of claim 14, wherein the diffractive element for each selection region comprises a coupling section that has a smaller two-dimensional extent than the assigned selection region.

27. The detector system of claim 14, wherein the control device is configured to take the determined distance as a basis for changing the value of a measurement parameter and/or output parameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 shows a schematic representation of an embodiment of the detector;

[0043] FIG. 2 shows a view of the front 7 of the base body 6 of the detector system 1 in FIG. 1;

[0044] FIG. 3 shows a view of the sensor device 4 of the detector system of FIG. 1;

[0045] FIG. 4 shows a view of the front of a further base body 6 according to a further embodiment of the detector system 1;

[0046] FIG. 5 shows a view of the front 7 of a further embodiment of the base body 6 of a further detector system 1;

[0047] FIG. 6 shows a side view of the detector system 1 of FIG. 5;

[0048] FIG. 7 shows a schematic representation for explaining a further embodiment of the detector system 1;

[0049] FIG. 8 shows a schematic representation for explaining a further embodiment of the detector system 1;

[0050] FIG. 9 shows a view of the front 7 of a transparent base body 6 of a further embodiment of the detector system 1;

[0051] FIG. 10 shows a side view of the detector system 1 of FIG. 9;

[0052] FIG. 11 shows a view of the front 7 of the base body 6 of a further embodiment of the detector system 1;

[0053] FIG. 12 shows a view of the front 7 of the base body 6 of a further embodiment of the detector system 1;

[0054] FIG. 13 shows a view of the front 7 of the base body 6 of a further embodiment of the detector system 1;

[0055] FIG. 14 shows a view of the front 7 of the base body 6 of a further embodiment of the detector system 1;

[0056] FIG. 15 shows a side view of the detector system 1 of FIG. 14;

[0057] FIG. 16 shows a schematic representation of a further embodiment of the detector system, and

[0058] FIG. 17 shows a schematic representation of a further embodiment of the detector system.

DETAILED DESCRIPTION

[0059] In the embodiment shown in FIG. 1, the detector system 1 includes a waveguide 2, a display device 3, a sensor device 4 and a control device 5.

[0060] The waveguide comprises a transparent base body 6 having a front 7 and a rear 8. In the exemplary embodiment described here, the base body 6 is in the form of a plane-parallel plate, which means that both the front 7 and the rear 8 are flat. The base body 6 can be made of glass or plastic, for example.

[0061] The base body 6 comprises a coupling region 9 and a decoupling region 10 spaced apart therefrom, a volume hologram 11, 12 being formed both in the coupling region 9 and in the decoupling region 10.

[0062] As shown schematically in FIG. 1, at least a portion of a radiation 13 that enters the transparent base body 6 via the front 7 and is incident on the volume hologram 11 of the coupling region 9 is deflected by means of the volume hologram 11 in such a way that the deflected portion is guided as coupled-in radiation by reflections on the rear 8 and the front 7 as far as the volume hologram 12 of the decoupling region 11. The reflections on the rear 8 and the front 7 can be total internal reflections. However, it is also possible for the front 7 and the rear 8 to have a partially reflective or reflective coating at least in the region for guiding the coupled-in radiation.

[0063] At least a portion of the coupled-in radiation that is incident on the volume hologram 12 of the decoupling region 10 is deflected by means of the volume hologram 12 in such a way that said portion emerges from the transparent base body 6 via the rear 8 and is incident on the sensor device 4 positioned behind the rear 8.

[0064] The display device 3, which can be e.g. an LCD display, is also arranged behind the rear 8 of the transparent base body 6. The display device is designed in such a way and/or is controlled by means of the control device 5 in such a way that it shows multiple selection regions A.sub.1, A.sub.2, A.sub.3, A.sub.4, A.sub.5, A.sub.6 in the coupling region 9. This is shown by way of example by the letters A, B, C, D, E and F in the view of the front of the transparent base body in FIG. 2. Each of the letters represents a single selection region. The square frame drawn around each of the letters can also be shown or can be omitted. Of course, the representation is not limited to the letters shown. It is possible e.g. for any image, symbols, numbers, multiple letters or text to be displayed.

[0065] The coupling region 9 can therefore also be referred to as a display region 9 of the base body 6 in which selectable selection regions are shown in such a way that they can be seen when the front 7 is viewed.

[0066] The volume hologram 11 of the coupling region 9 is designed in such a way that each selection region A.sub.1-A.sub.6 has an assigned coupling section 9.sub.1, 9.sub.2, 9.sub.3, 9.sub.4, 9.sub.5 and 9.sub.6. Each of these coupling sections 9.sub.1-9.sub.6 has an assigned decoupling section 10.sub.1, 10.sub.2, 10.sub.3, 10.sub.4, 10.sub.5 and 10.sub.6, on which the portion of the coupled radiation that was deflected by the applicable coupling section 9.sub.1-9.sub.6 is incident, as indicated by the dashed lines 13.sub.1, 13.sub.2, 13.sub.3, 13.sub.4, 13.sub.5 and 13.sub.6.

[0067] As shown schematically in FIG. 3, the sensor device 4 is in the form of a line sensor having six sensor sections 4.sub.1, 4.sub.2, 4.sub.3, 4.sub.4, 4.sub.5 and 4.sub.6, each sensor section 4.sub.1-4.sub.6 being assigned to one of the decoupling sections 10.sub.1-10.sub.6. Thus, the radiation decoupled by the decoupling section 10.sub.1 is incident on the sensor section 4.sub.1.

[0068] The sensor device 4 continuously measures the intensity of the sensor sections 4.sub.1-4.sub.6 and supplies these measurement results to the control device 5, which comprises a processor for carrying out the applicable calculation and control.

[0069] If, for example, a user now wants to select the selection region containing the letter A, he can position his finger 14 in front of the front 7 of the base body 6 and in front of the selection region containing the letter A (without touching the front 7), causing a change in the light intensity in front of the coupling section 9.sub.1 (less light is coupled in via the coupling section 9.sub.1, since the finger 14 leads to a certain amount of shadowing). As a result of light being coupled in via the applicable coupling section 9.sub.1 and the coupled-in light 13.sub.1 being guided as far as the decoupling section 10.sub.1, which directs the light onto the sensor section 4.sub.1, the sensor section 4.sub.1 will measure a lower light intensity and forward this measurement result to the control device 5. Due to the reduced intensity, the control device 5 can ascertain that the selection region containing the letter A has been selected.

[0070] A contactless area sensor is thus provided which can be used universally and has low susceptibility to faults even in different lighting conditions.

[0071] The transparent base body 6 can be spaced apart from the display device 3 (also called display apparatus 3 below), as shown schematically in FIG. 1. However, it is also possible for the base body 6 to be connected to the display device 3. In particular, the display device 3 itself can be used as a transparent base body 6. In this case, only the volume holograms 11 and 12 need to be formed in the display device 3, so that the transparent base body 6 is then realized by the display device 3. In particular, the display device 3 can contain an optoelectronic element (for example an LCD element or an OLED element), which is embedded in the base body 6, as shown schematically in FIG. 16. The display devices 3 described so far can therefore also be referred to as active display devices 3.

[0072] It is also possible to use a holographic element 23 (e.g. a holographic diffusing screen) for the display devices 3, which element can also be embedded in the base body 6, as shown schematically in FIG. 17. The holographic element can be used to show dynamic or static content. The illumination (or reconstruction of the hologram as part of the display device 3) can be implemented in various ways. There can thus be provision for active illumination L1 - L3, the illumination L1 being arranged on the rear 8, the illumination L2 being arranged on the end and the illumination L3 being arranged on the front 7. Of course, there is preferably provision for only one of the three illuminations L1 - L3. Alternatively, the hologram can also be designed in such a way that the illumination is produced using sunlight (indicated by arrow L4). The illumination L1 - L3 can be referred to as active illumination and the illumination using sunlight can be referred to as passive illumination.

[0073] FIG. 4 describes an embodiment in which there is provision for two lots of six coupling sections 9.sub.1-9.sub.6 and 9.sub.7, 9.sub.8, 9.sub.9, 9.sub.10, 9.sub.11 and 9.sub.12. These two lots of six coupling sections 9.sub.1-9.sub.6 and 9.sub.7-9.sub.12 are arranged vertically one above the other (in the direction of propagation). By contrast, the assigned twelve decoupling sections 10.sub.1-10.sub.6 and 10.sub.7, 10.sub.8, 10.sub.9, 10.sub.10, 10.sub.11 and 10.sub.12 are spaced apart from each other in the horizontal direction, as shown in FIG. 4. Arranged behind these two regions of decoupling sections 10.sub.1-10.sub.6 and 10.sub.7-10.sub.12 are two regions having six sensor sections each, so that each coupling section 9.sub.1-9.sub.12 has an assigned sensor section by way of the decoupling sections 10.sub.1-10.sub.12. The decoupling sections 10.sub.1-10.sub.6 and 10.sub.7-10.sub.12 are spaced apart from one another in the horizontal direction in order to achieve resolution in the vertical direction (direction of propagation) and to avoid interference for the sections of the volume hologram 11 of the coupling region 9 as far as possible. Therefore, the propagation angles to the decoupling sections 10.sub.1-10.sub.12 and thus to the sensor sections of the sensor device 4 from the coupling sections 9.sub.1-9.sub.6 and the coupling sections 9.sub.7-9.sub.12, on the other hand, are as different as possible.

[0074] In the solution shown in FIG. 4, the decoupling sections 10.sub.1-10.sub.12 and thus the sensor sections of the sensor device 4 are formed at different locations on the transparent base body 6. Alternatively, it is possible to select the greatest possible distances for the different vertical input options (coupling sections 9.sub.1-9.sub.6 on the one hand and coupling sections 9.sub.7-9.sub.12 on the other hand) within the decoupling sections 10.sub.1-10.sub.12. Of course, this then also applies to the sensor sections of the sensor device 4. By comparing the voltage differences on the individual sensor sections, the correct input value can then be reliably identified.

[0075] An exemplary embodiment is shown in FIG. 5, in which the sensor device 4 comprises a 2D RGB sensor that is positioned behind the rear 8, as shown in FIG. 6. In this embodiment, the different selection regions in the horizontal direction (double-headed arrow 15) are resolved by way of the propagation angle, as in the embodiment described in connection with FIG. 4. The different selection regions in the vertical direction (double-headed arrow 16) are resolved by way of the wavelengths. In order to achieve this, the volume hologram 11 of the coupling region 9 is manufactured in such a way that it diffracts the incident light according to the position in the horizontal and vertical directions in such a way that for each selection region (and thus for each coupling section 9.sub.1-9.sub.15) an accordingly different combination of propagation angle and wavelength occurs for the decoupling region 10, or the decoupling sections 10.sub.1-10.sub.15, and thus for the sensor sections of the sensor device 4. The control device 5 can then interpret the applicable values from the sensor device 4.

[0076] In the embodiment shown in FIG. 7, an exposed lens element function is used for input recognition, said function preferably being incorporated in the volume hologram 12 of the decoupling region 10. The selectivity of the object point can be adjusted by way of the exposure of the volume holograms, by exposing a strong angle dependency into the volume hologram 12 of the decoupling region 10. For this purpose, a holographically exposed lens element, the effect of which is indicated in the schematic representation in FIG. 7, is incorporated in each decoupling section 10.sub.1-10.sub.12. The focal length of this exposed lens element lies in a focal plane 17 in front of the front 7 of the transparent base body 6 and defines the distance of the object 14 to be detected from the front 7 at which the object 14 is ideally reproduced on the sensor device 4. FIG. 7 also schematically shows the intensity distribution 18 for each decoupling section 10.sub.1-10.sub.4 for the object 14 when positioned within the focal plane 17 (solid line) and when positioned in front of the focal plane 17 (dashed line). Different contrast areas (spots) are thus created on the sensor device 4, which are assigned to the individual selection regions (coupling sections 9.sub.1-9.sub.4). If an object 14 comes close to the focal plane 17, changes in intensity are registered on the sensor device 4. Thus, a spatial resolution of the input can be recognized. By defining a threshold value for the intensity at the focal point, it is possible to make the input for an application. As shown schematically in FIG. 7, the closer the object 14 is to the focal plane 17, the greater the light intensity, or the contrast, on the sensor device 4. The aberrations increase as the distance between the object 14 and the respective optical axis OA.sub.1, OA.sub.2, OA.sub.3 and OA.sub.4 increases. Also shown in FIG. 7 is the sensitive angle range 19 of the coupling section 9.sub.1.

[0077] This described change in contrast with distance from the focal plane 17 can also be evaluated in such a way that it results in the distance of the object 14 from the focal plane 17 (and thus also from the front 7) being detected. This change in the distance from the focal plane 17 (or from the front 7) can be used as an input variable for setting a parameter, such as for controlling the volume of an audio output. As such, e.g. the volume can be increased if the object 14 is moved towards the focal plane 17 and the distance from the focal plane 17 thus decreases. Other parameters can also be controlled in this way, such as the brightness of what is shown in the display region or other parameters for the display.

[0078] The distance of the object 14 from the front 7 can also be detected by spectral resolution.

[0079] For this purpose, as shown schematically in FIG. 8, both the volume hologram 11 of the coupling section 9.sub.1 and the volume hologram 12 of the decoupling section 10.sub.1 are each formed using a lens element function. Depending on the spectral value, or wavelength, the focal plane of the volume hologram 11 for the coupling section 9.sub.1 is different distances away from the front 7 of the transparent base body 6. The distance decreases from blue to green to red and infrared (in particular NIR). If the coupling region 9 is actively illuminated and the wavelength of the illumination is known, the focal plane and thus the distance from the front 7 of the transparent base body 6 are also known.

[0080] The lens element function in the volume hologram 12 of the decoupling section 10.sub.1 comprises the same spectral characteristic, which means that the distance from the rear 8 decreases from blue to green to red and infrared.

[0081] The sensor device 4 is in the form of a spectrally selective sensor device 4 and can include e.g. an RGB sensor. The control device 5 can then use the intensity values on the basis of the applicable wavelengths to recognize the selection of the applicable coupling section 9.sub.1. Additionally or alternatively, the distance of the object 14 from the front 7 can be detected, which in turn allows a parameter (such as the volume) to be controlled.

[0082] Up to now, the holograms 11 and 12 have always been described as volume holograms. Of course, different types of holograms can be used. In particular, diffractive elements and in particular relief gratings can be used. When using volume gratings and volume holograms, however, there is the advantage of selectivity for angle and wavelength. The filter function thus means that stray light (radiation that is irrelevant to the function of the solution) cannot be coupled in and/or cannot be forwarded to the sensor device 4. This can contribute to higher precision and robustness.

[0083] In the embodiments described so far, the selection regions A-F can be found next to one another. Interference (e.g. from scattered light) can be reduced if each selection region has a different coupling grating and the propagation angles of adjacent selection regions are chosen to be as different as possible, as is shown schematically below for the selection regions with the letters A, B and C in FIGS. 9 and 10.

[0084] A further possibility for reducing interference is described in connection with FIG. 11. Here, the object 14 used to make the input is actively illuminated from the display plane. The reflected light can be captured and used to select the input. This reduces interference caused by possibly unwanted shadowing. Moreover, this allows use in the dark.

[0085] The active illumination can be implemented e.g. by way of an LED frame 20 around the coupling region 9 (FIG. 11). However, a second hologram 21 around the coupling region 9 (FIG. 12) or under the volume hologram 11 of the coupling region 9 (FIG. 13) can also be used for this purpose, the second hologram 21 being able to decouple white light, for example, which is coupled in by a defined point 22 on the transparent base body 6. It is merely necessary to ensure that the propagating waves of the second hologram 21 and of the volume hologram 11 of the coupling region 9 do not interfere with one another. The illumination function from a micro-optical structure in the transparent base body 6 means that the transparent base body 6 itself can remain transparent.

[0086] The active illumination can also take place as a result of illumination of the selection regions on the front 7 from the base body 6. In this case, the source for the coupled-in light can be chosen to be locally different, as is shown schematically in FIG. 13.

[0087] In order to optimize the beam guidance and arrangement of the propagation angles, the volume hologram 11 for the coupling region 9 does not have to cover the entire area of the selection regions, but can also be very narrow, as indicated in FIG. 14. For this purpose, a coupling grating 11 exposed to a plane wave can be divided into multiple strips 11.sub.1, 11.sub.2, which can then be used for coupling in the respective selection regions in the vertical direction. The purpose of this is that after the beams have been coupled in, they do not strike another coupling grating 11 on their way to the decoupling region 10, since they would otherwise interfere and thus not be able to be resolved again at the sensor device 4. Dividing the coupling grating 11 into coupling strips 11.sub.1, 11.sub.2 allows larger areas in the transparent base region 6 to be functionalized and inputs to be read reliably. Furthermore, it becomes easier to find suitable propagation angles for transporting the radiation to the decoupling region 10, and multiple lines in the coupling region 9 can use only one decoupling grating with a photosensitive chip (sensor device 4) for detection.

[0088] In order for a complete image to result at the sensor device 4 of the decoupling grating 12 in the embodiment described, the vertical height of the coupling grating 11 may be only the same as that of the sensor device 4. In order to still achieve an optimum resolution for different heights, a lens element function can be exposed into the decoupling grating 12, said function ensuring that the radiation of the individual coupling strips 11.sub.1, 11.sub.2 of the coupling grating 11 again is incident on the sensor device 4 as an overall image with the correct scaling via the decoupling grating (as shown schematically in FIG. 16).

[0089] In the case of stray light, the detector system 1 described here can result in misinterpretations when evaluating the change in light intensity on the sensor device 4. In order to reduce this, the control device 5 can compare light values of all the selection regions with one another and define non-changing values over the travel time as static values. These values can be ignored when evaluating the changes in intensity. Thus, light values that do not belong to the application can be removed as background noise and the actual calculation of the change in intensity to identify an input becomes more reliable.

[0090] Another way of improving the robustness of the detector system 1 is to expose a lens element function on the coupling grating and the decoupling grating. In this way, differences in intensity can be registered much better and incorrect interpretations in the input can be reduced.

[0091] Furthermore, an exposed lens element function on the coupling grating allows the light to be guided from the coupling grating to the decoupling grating in parallel, or as a parallel pencil of rays. Less light is thus lost on the way to the sensor device 4 and stray light is reduced.

[0092] If a selection region is approached with an object 14, a specific change in light intensity occurs at the decoupling grating in a specific angle range (more light with active illumination; less light with passive illumination). The volume hologram with the lens element function is only efficient for one angle range. A sharp change in intensity occurs on the sensor device for the selection region on the sensor device. Adjacent selection regions achieve little or no changes in intensity on the sensor device, since the angle range is not efficient for them.

[0093] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed embodiments. It will be readily apparent to those of ordinary skill in the art that many modifications and equivalent arrangements can be made thereof without departing from the spirit and scope of the present disclosure, such scope to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products. Moreover, features or aspects of various example embodiments may be mixed and matched (even if such combination is not explicitly described herein) without departing from the scope of the invention.