DETECTOR FOR DETERMINING A POSITION OF AT LEAST ONE OBJECT

Abstract

Described herein is a detector for determining a position of at least one object. The detector includes: at least one transfer device; at least one illumination source adapted to generate at least one light beam for illuminating the object; at least one first optical receiving fiber and at least one second optical receiving fiber; at least two optical sensors; and at least one evaluation device being configured for determining at least one longitudinal coordinate z of the object by evaluating a combined signal Q from the sensor signals.

Claims

1. A detector (112) for determining a position of at least one object (114), the detector (112) comprising: at least one transfer device (130), wherein the transfer device (130) has at least one focal length in response to the at least one incident light beam propagating from the object (114) to the detector (112), wherein the transfer device (130) has at least one optical axis (142); at least one illumination source (144) adapted to generate at least one light beam (146) for illuminating the object (114), wherein an exit pupil of the illumination source (144) is displaced from the optical axis (142) by a distance BL; at least one first optical receiving fiber (120, 126) and at least one second optical receiving fiber (120, 124), wherein each of the optical receiving fibers (120, 126, 128) comprises at least one cladding (136) and at least one core (134), wherein the first optical receiving fiber (120, 122) has a core diameter of d.sub.1, wherein the second optical receiving fiber (120, 124) has a core diameter of d.sub.2, wherein a ratio d.sub.1/BL is in a range 0.000047≤d.sub.1/BL≤313 and/or wherein a ratio d.sub.2/BL is in a range 0.000047≤d.sub.2/BL≤313; at least two optical sensors (126, 128), wherein at least one first optical sensor (126) is arranged at an exit end of the first optical receiving fiber (120, 122) and at least one second optical sensor (128) is arranged at an exit end of the second optical receiving fiber (120, 124), wherein each optical sensor (126, 128) has at least one light sensitive area (147), wherein each optical sensor (126, 128) is designed to generate at least one sensor signal in response to an illumination of its respective light-sensitive area (148) by a light beam having passed through the respective optical receiving fiber (120, 122, 124); and at least one evaluation device (150) being configured for determining at least one longitudinal coordinate z of the object (114) by evaluating a combined signal Q from the sensor signals.

2. The detector (112) according to claim 1, wherein the ratio d.sub.1/BL is in a range 0.000114≤d.sub.1/BL≤30.37, and/or wherein the ratio d.sub.2/BL is in a range 0.000114≤d.sub.2/BL≤30.37.

3. The detector (112) according to claim 2, wherein the illumination source (144) comprises at least one optical sender fiber (118) for illuminating the object (114).

4. The detector (112) according to claim 1, wherein the illumination source (144) has a geometrical extend G in a range 1.5.Math.10.sup.−7 mm.sup.2.Math.sr≤G≤314 mm.sup.2.Math.sr.

5. The detector (112) according to claim 1, wherein the illumination source (144) is configured to illuminate the object (114) under an angle α.sub.illu with respect to the optical axis (142), wherein the angle is in a range 0°≤α.sub.illu≤40.

6. The detector (112) according to claim 1, wherein at least one of the optical receiving fibers (120, 122, 124) and/or the transfer device (130) has a ratio ε.sub.r/k in a range 0.362 (m.Math.K)/W≤ε.sub.r/k≤1854 (m.Math.K)/W, wherein k is the thermal conductivity and ε.sub.r is the relative permittivity.

7. The detector (112) according to claim 1, wherein the transfer device (130) has a ratio v.sub.e/n.sub.D in a range 9.05≤v.sub.e/n.sub.D≤77.3, wherein v.sub.e is the Abbé-number and n.sub.D is the refractive index, wherein the Abbé-number v.sub.e is given by $v_{e} = \frac{(n_{D} - 1)}{(n_{F} - n_{c})},$ wherein n.sub.i is the refractive index for different wavelengths, wherein n.sub.C is the refractive index for 656 nm, n.sub.D is the refractive index for 589 nm and n.sub.F is the refractive index for 486 nm.

8. The detector (112) according to claim 1, wherein a product αΔn is in a range 0.0004 dB/km≤αΔn≤110 dB/km at least one wavelength in a visual and near infrared wavelength range, wherein α is the attenuation coefficient and Δn is the refractive index contrast with Δn=(n.sub.1.sup.2−n.sub.2.sup.2)/(2n.sub.1.sup.2), wherein n.sub.1 is the maximum core refractive index and n.sub.2 is the cladding refractive index.

9. The detector (112) according to claim 1, wherein the transfer device (130) has an aperture area D.sub.1 and at least one of the optical receiving fibers (120, 122, 124) has a fiber core (134) with a cross-sectional area D.sub.2, wherein a ratio D.sub.1/D.sub.2 is in a range 0.54≤D.sub.1/D.sub.2≤5087.

10. The detector (112) according to claim 1, wherein each of the first and the second optical receiving fibers (120, 122, 124) comprises at least one entrance face configured to receive the light beam propagating from the object (114) to the detector (112) having passed through the transfer device (130), wherein a centroid of the entrance faces of the first and second optical receiving fibers (120, 122, 124) is displaced from the optical axis (142) by a distance d.sub.R, wherein d.sub.R is in a range 10 μm≤d.sub.R≤127000 μm.

11. The detector (112) according to claim 1, wherein the evaluation device (150) is configured for deriving the combined signal Q by one or more of dividing the sensor signals, dividing multiples of the sensor signals, or dividing linear combinations of the sensor signals.

12. The detector (112) according to claim 11, wherein the evaluation device (150) is configured for using at least one predetermined relationship between the combined signal Q and the longitudinal coordinate for determining the longitudinal coordinate.

13. The detector (112) according to claim 1, wherein the evaluation device (150) is configured for deriving the combined $Q (z_{O}) = \frac{\underset{A_{1}}{\int \int} .Math. E (x, y; z_{O}) .Math. d .Math. xdy}{\underset{A_{2}}{\int \int} .Math. E (x, y; z_{O}) .Math. d .Math. x .Math. d .Math. y}$ wherein x and y are transversal coordinates, A.sub.1 and A.sub.2 are areas of the beam profile at a sensor position of the optical sensors (126, 128), and E(x,y,z.sub.o) denotes the beam profile given at the object distance z.sub.o.

14. The detector (112) according to claim 1, wherein each of the sensor signals comprises at least one information of at least one area of the beam profile of the light beam, wherein the beam profile is selected from the group consisting of a trapezoid beam profile; a triangle beam profile; a conical beam profile and a linear combination of Gaussian beam profiles, wherein the light-sensitive areas (148) are arranged such that a first sensor signal comprises information of a first area of the beam profiles and a second sensor signal comprises information of a second area of the beam profile, wherein the first area of the beam profile and the second area of the beam profile are one or both of adjacent or overlapping regions, wherein the evaluation device (150) is configured to determine the first area of the beam profile and the second area of the beam profile, wherein the first area of the beam profile comprises essentially edge information of the beam profile and the second area of the beam profile comprises essentially center information of the beam profile, wherein the edge information comprises information relating to a number of photons in the first area of the beam profile and the center information comprises information relating to a number of photons in the second area of the beam profile, wherein the evaluation device (150) is configured to derive the combined signal Q by one or more of dividing the edge information and the center information, dividing multiples of the edge information and the center information, dividing linear combinations of the edge information and the center information.

15. The detector (112) according to claim 1, wherein each optical receiving fiber (120, 122, 124) has at least one entrance face, wherein a geometrical center of the respective entrance face is aligned perpendicular with respect to the optical axis (142) of the transfer device (130).

16. The detector (112) according to claim 1, wherein at least one of the optical receiving fibers (120, 122, 124) is a structured fiber having a shaped and/or structured entrance and/or exit face.

17. The detector (112) according to claim 1, wherein the optical sensors are non-pixelated optical sensors.

18. A method for determining a position of at least one object (114) by using at least one detector (112), the method comprising the following steps: providing at least one transfer device (130), wherein the transfer device (130) has at least one focal length in response to the at least one incident light beam propagating from the object (114) to the detector (112), wherein the transfer device (130) has at least one optical axis (142); providing at least one illumination source (144) adapted to generate at least one light beam (146) for illuminating the object (114), wherein the illumination source (144) is displaced from the optical axis (142) by a distance BL; providing at least one first optical receiving fiber (120, 122) and at least one second optical receiving fiber (122, 124), wherein each of the optical receiving fibers (120, 122, 124) comprises at least one cladding (136) and at least one core (134), wherein the first optical receiving fiber (120, 122) has a core diameter of d.sub.1, wherein the second optical receiving fiber (120, 124) has a core diameter of d.sub.2, wherein a ratio d.sub.1/BL is in a range 0.000047≤d.sub.1/BL≤313 and/or wherein a ratio d.sub.2/BL is in a range 0.000047≤d.sub.2/BL≤313; providing at least two optical sensors (126, 128), wherein at least one first optical sensor (126) is arranged at an exit end of the first optical receiving fiber (120, 122) and at least one second optical sensor is arranged at an exit end of the second optical receiving fiber (120, 124), wherein each optical sensor (126, 128) has at least one light sensitive area (148), wherein each optical sensor (126, 128) is designed to generate at least one sensor signal in response to an illumination of its respective light-sensitive area (148) by the light beam generated by the object (114) having passed through the respective optical receiving fiber (120, 122, 124); illuminating the light-sensitive area (148) of at least one of the optical sensors (126, 128) with the light beam having passed through the first optical receiving fiber (120, 122) and illuminating the light-sensitive area (148) of the other one of the optical sensors (126, 128) with the light beam having passed through the second optical receiving fiber (120, 124), wherein, thereby, each of the light-sensitive areas (148) generates at least one sensor signal; and evaluating the sensor signals, thereby, determining at least one longitudinal coordinate z of the object (114), wherein the evaluating comprises deriving a combined signal Q of the sensor signals.

19. A method of using the detector (112) according to claim 1, the method comprising using the detector (112) for a purpose selected from the group consisting of: a position measurement in traffic technology; an entertainment application; an optical data storage application; a security application; a surveillance application; a safety application; a human-machine interface application; a logistics application; an endoscopy application; a medical application; a tracking application; a photography application; a machine vision application; an industrial sensing application; a robotics application; a quality control application; a 3D printing application; an augmented reality application; a manufacturing application; and a purpose in combination with optical data storage and readout.

20. The detector (112) according to claim 1, wherein the ratio d.sub.1/BL is in a range 0.000318≤d.sub.1/BL≤6.83, and/or wherein the ratio d.sub.2/BL is in a range 0.000318≤d.sub.2/BL≤6.83.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0236] 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 in an isolated fashion or in combination with other features. 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.

[0237] Specifically, in the figures:

[0238] FIGS. 1A to JJ show top views of exemplary embodiments of a measurement head of a detector according to the present invention;

[0239] FIGS. 2A and GG show top views of embodiments of lens and fiber arrangement according to the present invention;

[0240] FIGS. 3A and B shows side views of embodiments of a measurement head according to the present invention;

[0241] FIGS. 4A to F shows further embodiments of optical fibers according to the present invention;

[0242] FIGS. 5A to E show further embodiments of a measurement head according to the present invention;

[0243] FIG. 6 shows an embodiment of an optical receiving fiber according to the present invention;

[0244] FIG. 7 shows a schematic detector setup according to the present invention; and

[0245] FIG. 8 shows experimental results of distance measurement.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0246] FIGS. 1A to JJ show in top view exemplary embodiments of a measurement head 110 of a detector 112 for determining a position of at least one object 114. The measurement head 110 may comprise at least one housing 116, for example at least one metal housing and/or plastic housing. Each of the measurement heads 110 may comprise a plurality of fibers, specifically a plurality of the at least one optical sender fiber 118 and/or at least two optical receiving fibers 120 such as at least one first optical receiving fiber 122 and at least one second optical receiving fiber 124. The first optical receiving fiber 122 may be configured to provide at least one impinging light beam to at least one first optical sensor 126 which is arranged at an exit end of the first optical receiving fiber 122. The second optical receiving fiber 124 may be configured to provide at least one impinging light beam to at least one second optical sensor 128 which is arranged at an exit end of the second optical receiving fiber 124. Each of the optical receiving fibers 120 may comprise an exit end and an entrance end. In FIGS. 1A to JJ top view on the entrance end is shown.

[0247] FIGS. 1A to 1D, 1I to 1K, and 1FF to 1JJ show embodiments of measurement head 110 having one optical sender fiber 118 and one first optical receiving fiber 122 and one second optical receiving fiber 124. In FIGS. 1A to D and 11 to 1K the measurement head 110 may have an elliptic cross section and the optical sender fiber 118, the first optical receiving fiber 122 and the second optical receiving fiber 124 may have a circular cross section. In FIGS. 1FF to 1JJ the measurement head may have a rectangular shape and the optical sender fiber 118, the first optical receiving fiber 122 and the second optical receiving fiber 124 may have a rectangular cross section. In the embodiments of FIGS. 1A to 1D and 1FF to 1JJ the optical sender fiber 118, the first optical receiving fiber 122 and the second optical receiving fiber 124 may be arranged side by side and in parallel. For example, in FIG. 1A the optical sender fiber 118 may be arranged next to the second optical receiving fiber 124 which may be arranged next to the first optical receiving fiber 122. Similar arrangements are shown in FIGS. 1HH and 1JJ, with different order of the respective optical fibers. The optical sender fiber 118, the first optical receiving fiber 122 and the second optical receiving fiber 124 may be arranged displaced from each other such as shown in FIGS. 1B, 1C, 1GG and 1II. For example, as shown in FIGS. 1B and 10, the second optical receiving fiber 124 may arranged next to the optical sender fiber 118, wherein the first optical receiving fiber 122 may be displaced from the two fibers by a certain distance. As shown in FIGS. 1B and 1C different order of the second optical receiving fiber 124 and the optical sender fiber 118 may be possible. For example, as shown in FIG. 1D, the first optical receiving fiber 122 may be arranged next to the optical sender fiber 118, wherein the second optical receiving fiber 124 may be displaced from the two fibers by a certain distance. Similar arrangements are shown in FIGS. 1FF, 1GG and 1II with different order of the respective optical fibers. In addition, to the embodiments as shown in the FIGS. 1A to D and 1FF to 1JJ, every conceivable order of the optical sender fiber 118, the first optical receiving fiber 122 and the second optical receiving fiber 124 may be possible. For example, in FIG. 1I, the second optical receiving fiber 124 may be arranged concentric around the first optical receiving fiber 122, wherein the optical sender fiber 118 may be arranged side by side next to the optical receiving fibers 120. For example, in FIG. 1J the first optical receiving fiber 122 may be arranged concentric around the optical sender fiber 118, wherein the second optical receiving fiber 124 may be arranged parallel to the first optical receiving fiber 122 and the optical sender fiber 118. For example, in FIG. 1K the measurement head 110 may comprise one optical sender fiber 118 which is arranged concentric around one first optical receiving fiber 122 and one second optical receiving fiber which is arranged parallel to the first optical receiving fiber 122 and the optical sender fiber 118.

[0248] FIGS. 1E to 1G, 1L to 1EE show embodiments, wherein the measurement head 110 comprises a plurality of the first optical receiving fiber 122 and/or of the second optical receiving fiber 124 and/or of the optical sender fiber 118. FIGS. 1E, 1F, 1G, 1L to 1N and 1W to 1X show embodiments wherein two or more of the first optical receiving fiber 122, the second optical receiving fiber 124 and the optical sender fiber 118 may be arranged concentric and having and/or sharing a common central axis. For example, in FIG. 1E, the measurement head 110 may comprise two first optical receiving fibers 122, one optical sender fiber which may be arranged concentric around one of the first optical receiving fibers 122, and one second optical receiving fiber 124 which may be arranged concentric around the other one of the first optical receiving fibers 122. For example, in FIG. 1F, the measurement head 110 may comprise two second optical receiving fibers 124, one optical sender fiber 118 which may be arranged concentric around one of the second optical receiving fibers 124, and one first optical receiving fiber 122 wherein the other one of the second optical receiving fibers 124 may be arranged concentric around the first optical receiving fiber 122. For example, in FIG. 1G, the measurement head 110 may comprise two first optical receiving fibers 122, one optical sender fiber 118, wherein one of the first optical receiving fibers may be arranged concentric around the optical sender fiber 118, and one second optical receiving fiber 124 which may be arranged concentric around the other one of the first optical receiving fibers 122. For example, in FIG. 1N, the measurement head 110 may comprise two second optical receiving fibers 124 wherein one of the second optical receiving fibers 124 may be arranged concentric around one first optical receiving fiber 122, and the other one of the second optical receiving fibers 124 may be arranged concentric around one optical sender fiber 118. For example, in FIG. 1L, the measurement head 110 may comprise seven optical sender fibers 118 which may be arranged concentric around one second optical receiving fiber 124. One first optical receiving fiber 122 may be arranged parallel to the second optical receiving fiber 124 and the optical sender fibers 118. For example, in FIG. 1M, the measurement head 110 may comprise seven first optical receiving fibers 122 which may be arranged concentric around one second optical receiving fiber 124. One optical sender fiber 118 may be arranged parallel to the first and second optical receiving fibers 122, 124. For example, in FIG. 1W, the measurement head 110 may comprise seven optical sender fibers 118 which may be arranged concentric around one second optical receiving fiber 124, and seven first optical receiving fibers 122 which may be arranged concentric around one second optical receiving fiber 124. For example, in FIG. 1X, the measurement head 110 may comprise eight optical sender fibers 118 wherein seven of the optical sender fibers 118 may be arranged concentric around one of the optical sender fibers 118, and seven first optical receiving fibers 122 which may be arranged concentric around one second optical receiving fiber 124. Other embodiments of a radially arranged or radial symmetric design are possible. The radially arranged or radially symmetric design may allow enhancing robustness of measurement values, in particular at strong black-and-white contrast in a measured point of the object or for measurements of concave or convex surfaces.

[0249] FIGS. 1O to 1V, 1Y to 1EE show non-radial symmetric design. In addition, to the embodiments as shown in the FIGS. 1O to 1V, 1Y to 1BB, 1DD and 1EE every conceivable non-radial symmetric design of the optical sender fibers 118, the first optical receiving fibers 122 and the second optical receiving fibers 124 may be possible. Specifically, measurement heads 110 are possible with identical amount of optical sender fibers 118, first optical receiving fibers 122 and second optical receiving fibers 124 or with different amount of optical sender fibers 118 first optical receiving fibers 122 and second optical receiving fibers 124.

[0250] FIGS. 1H and 1R show embodiments of the measurement head 110 having a circular cross section. In FIG. 1H, the measurement head 110 comprises one optical sender fiber 118, one first optical receiving fiber 122 and one second optical receiving fiber 124. In FIG. 1R, the measurement head 110 comprises one optical sender fiber 118, one first optical receiving fiber 122 and two second optical receiving fibers 124. The amount and arrangement of the optical fibers is only exemplar. All possible amounts and radial and non-radial symmetric arrangements are possible

[0251] The measurement head 110 comprises one or more transfer devices 130, in particular collimating lenses. FIG. 2A to GG show in top view embodiments of lens arrangements in the measurement head 110. The arrangement of fibers in the measurement heads 110 of FIG. 2A to 2EE correspond to the arrangement shown in FIGS. 1A to 1EE. For clarity reference numbers of respective fibers were omitted such that reference is made to FIGS. 1A to 1EE. FIGS. 2FF and 2GG shows fiber arrangement corresponding to FIGS. 1H and 1R, respectively, but in this embodiment the measurement head 110 has a circular cross section. The measurement head 110 may comprise one transfer device 130 for each of the optical fibers or a common transfer device 130 for two or more optical fibers. For example, in FIG. 2A, the measurement head 110 comprise one transfer device 130 for each of the optical fibers. In FIG. 2B, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the first optical receiving fiber 122 and one transfer device 130 covers both the optical sender fiber 118 and the second optical receiving fiber 124. In FIGS. 2C, 2F, 2G, 2H, 2J, 2L, 2P, 2Q, 2R, 2T, 2V, 2AA, 2BB and 2EE the measurement head 110 comprises one transfer device 130 covering all optical fibers. In FIG. 2D, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the second optical receiving fiber 124 and one transfer device 130 covers both the optical sender fiber 118 and the first optical receiving fiber 122. In FIG. 2E, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers one of the first optical receiving fibers 122 surrounded by the second optical receiving fiber 124 and one transfer device 130 covers the other one of the first optical receiving fibers 122 surrounded by the optical sender fiber 118. In FIG. 21, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical sender fiber 118 and the other transfer device covers both of the first optical receiving fiber 122 and the second optical receiving fiber 124. In FIG. 2K, the measurement head 110 comprises three transfer devices 130, wherein one transfer device 130 covers both the optical sender fiber 118 and the first optical receiving fiber 122 and one transfer device 130 covers the second optical receiving fiber 124. A third transfer device 130 may be arranged such that it covers the first optical receiving fiber 122 only. In FIG. 2M, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical sender fiber 118 and the other transfer device 130 covers the first and second optical receiving fibers 122, 124. In FIG. 2N, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers all optical fibers and the other transfer device 130 covers the optical sender fiber 118 only. In FIG. 2O, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers all optical fibers and the other transfer device 130 covers the optical sender fibers 118, only. In FIG. 2S, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical sender fiber 118 and the other transfer device 130 covers the first and second optical receiving fibers 122, 124. In FIG. 2U, the measurement head 110 comprises three transfer devices 130, wherein one transfer device 130 covers the optical sender fiber 118, a second transfer device 130 covers the first optical receiving fibers 122 and a third transfer device 130 covers the second optical receiving fibers 124. In FIG. 2W, the measurement head 110 comprises four transfer devices 130, wherein one transfer device 130 covers one of the second optical receiving fibers 124 and the first optical receiving fibers surrounding said second optical receiving fiber 124, a second transfer device which covers the other one of the second optical receiving fibers 124 and the optical sender fibers 118 surrounding said second optical receiving fiber 124, a third transfer device 130 covering one of the second optical receiving fibers 124, only, and a fourth transfer device 130 covering the other one of the second optical receiving fibers 124, only. In FIG. 2X, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical receiving fibers 120 and the other transfer device 130 covers the optical sender fibers 118 only. In FIG. 2Y, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers all optical fibers and the other transfer device 130 covers the optical sender fibers 118 only. In FIG. 2Z, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical receiving fibers 120 and the other transfer device 130 covers the optical sender fibers 118 only. In FIGS. 2CC and 2DD, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers all optical fibers and the other transfer device 130 covers the optical sender fiber 118 only. In FIG. 2FF, the measurement head 110 comprises two transfer devices 130, wherein one transfer device 130 covers the optical receiving fibers 120 and the other transfer device 130 covers the optical sender fiber 118 only. In FIG. 2GG, an alternative fiber lens arrangement for the fiber arrangement of FIG. 1R is shown. In this embodiment, one transfer device 130 covers the one of the second optical receiving fibers 124 and the optical sender fiber 118 and the other transfer device 130 covers the other one of the second optical receiving fibers 124 and the first optical receiving fibers 122.

[0252] FIGS. 3A, 3B and FIGS. 5A to 5E show in a side view of embodiments of the measurement head 110. FIG. 3A corresponds to the fiber and lens arrangement depicted in FIGS. 1M and 2M. The measurement head 110 may comprise separate transfer devices 130 for optical sender fiber 118 and optical receiving fibers 120. The measurement head 110 may comprise one optical sender fiber 118. The measurement head 110 may comprise, in particular displaced from the optical sender fiber 118, one second optical receiving fiber 124 which is surrounded by six first optical receiving fibers 122 which are arranged radial around the second optical receiving fiber 124. The measurement head 110 may comprise a first transfer device 130, which may be arranged in front of the optical sender fiber 118, and a second transfer device 130 which may cover the first optical receiving fibers 122 and the second optical receiving fiber 124. FIG. 3B shows an embodiment of the measurement head 110 comprising one optical sender fiber 118, six first optical receiving fiber 122 and six second optical receiving fibers 124. The measurement head 110 may comprise one transfer device 130 covering all optical fibers. The optical sender fiber 118 may be guided up to the transfer device 130 such that internal reflections can be prevented.

[0253] FIGS. 5A to 5E show further embodiments of the measurement head 110. The lens and fiber arrangement in FIG. 5A corresponds to the lens and fiber arrangement as shown in FIG. 3A. In FIG. 5A, in addition the measurement head 110 comprises the spacer device 132 which is adapted to attach the transfer devices 130 to the optical fibers. The optical paths of the first optical receiving fiber 122 and/or the second optical receiving fiber 124 and/or the optical sender fiber 118 and/or the optical pathways of two or more transfer devices 130 may be fully or partially optically separated by mechanical means such as a fully or partially intransparent mechanical wall or cladding or the like to avoid internal reflections. This optical separation by mechanical means may be part of the spacer device 132. In FIG. 5B an arrangement comprising three fibers is shown. The optical sender fiber 118 may be arranged separately and parallel to the optical receiving fibers 120. The optical receiving fibers 120 may be arranged in one combined receiving fiber entrance end. A first transfer device 130 may be arranged in front of the entrance end of the optical receiving fibers 120 and a second transfer device 130 may be arranged in front of the exit end of the optical sender fiber 118. The combined receiving fiber entrance end may be split up into the first optical receiving fiber 122 and the second optical receiving fiber 124. For example, in a cross sectional view the first optical receiving fiber 122 and the second optical receiving fiber 124 may be arranged within the combined receiving fiber entrance end as half circles separated by a horizontal border. FIG. 5C shows a similar arrangement but in the embodiment of FIG. 5C, the first optical receiving fiber 122 and the second optical receiving fiber 124 may be arranged within the combined receiving fiber entrance end as half circles separated by a vertical border. FIG. 5D shows an arrangement wherein the first optical receiving fiber 122 and the second optical receiving fiber 124 and the optical sender fiber 118 each are designed as separated fibers. A first transfer device 130 may be arranged in front of the entrance end of the first optical receiving fiber 122 and a second transfer device 130 may be arranged in front of the entrance end of the second optical receiving fiber 124 and a third transfer device 114 may be arranged in front of the exit end of the optical sender fiber 118. The entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118 may be arranged in the same plane such as plane-parallel. The transfer devices 130 may be arranged plane-parallel but in a different plane compared to the plane of the entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118 such spaced apart from the plane of the entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118. The plane of the entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118 and the plane of the transfer devices 130 may be parallel planes. The centers of the exit end of the optical sender fiber 118 and the entrance ends of the optical receiving fibers 120 may be arranged at the intersection of a first plane which is the plane of the entrance faces of the optical receiving fibers 120 and the exit end of the sender fiber 118 with a second plane that is orthogonal to the first plane and comprises the line connecting the centers of the exit end of the optical sender fiber 118 and the entrance ends of the optical receiving fibers 120. In FIG. 5E, as in FIG. 5D, the first optical receiving fiber 122 and the second optical receiving fiber 124 and the optical sender fiber 118 are designed as separated fibers. In this embodiment, a first transfer device 130 may be arranged in front of the entrance end of the optical receiving fibers 120 and a second transfer device 130 may be arranged in front of the exit end of the optical sender fiber 118. As in FIG. 5D, the entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118 may be arranged in the same plane. The first transfer device 130 and/or the second transfer device 130 may be arranged non-parallel such as under an angle with respect to the plane of the plane of the entrance ends of the optical receiving fibers 120 and the exit end of the optical sender fiber 118.

[0254] FIGS. 4A to F show different lens arrangements at the fiber ends. As described above, at least one transfer device 130 may be arranged at an end of the optical fibers such as the optical receiving fibers 120 and/or the optical sender fiber 118. The transfer device 130 may be attached directly to one optical fiber or may be attached to a bundle of optical fibers. Alternatively, the transfer device 130 may be attached to the optical fiber or bundle of optical fibers using at least one spacer device 132. FIG. 4A shows an optical fiber or a bundle of optical fibers. FIG. 4B shows the optical fiber or bundle of optical fibers having attached at least one concave lens. FIG. 4C shows the optical fiber or bundle of optical fibers having attached at least one convex lens. FIG. 4D shows the optical fiber or bundle of optical fibers having attached at least one spherical lens. FIG. 4E shows the optical fiber or bundle of optical fibers having attached at least one conical lens or at least one tip-shaped lens. FIG. 4F shows the optical fiber or bundle of optical fibers having attached at least one prism shaped lens, in particular a non-rotationally symmetric lens.

[0255] FIG. 6 shows a highly schematic view of an embodiment of an optical receiving fiber 120. Each of the optical receiving fibers 120 may comprise the at least one fiber core 134 which is surrounded by the at least one fiber cladding 136. The fiber cladding 136 may have a lower index of refraction as the fiber core 134. The fiber cladding 136 may also be a double or multiple cladding. The fiber cladding 136 may be surrounded by a buffer 138 and an outer jacket 140. The fiber cladding 136 may be coated by the buffer 138 which is adapted to protect the optical receiving fiber 120 from damages and moisture. The buffer 138 may comprise at least one UV-cured urethane acrylate composite and/or at least one polyimide material.

[0256] The optical receiving fibers 120 may have specific mechanical properties to ensure stability of the distance measurement in a broad range of environments. The mechanical properties of the optical receiving fibers 120 may be identical or the mechanical properties of the optical receiving fibers 120 may differ. Without wishing to be bound by this theory, a light supporting function of optical receiving fibers 120 relies on relationships of refractive indices and certain energy transport properties. Further certain mechanical parameters may be prerequisite that all functions of the optical receiving fibers 120 are maintained in a stable way. Therefore, certain mechanical parameters may act as prerequisite to ensure a stable measurement itself. At least one of the optical receiving fibers 120 and/or the transfer device 130 may have a ratio ε.sub.r/k in the range 0.362 (m.Math.K)/W≤ε.sub.r/k≤1854 (m.Math.K)/W, wherein k is the thermal conductivity and ε.sub.r is the relative permittivity. The relative permittivity is also known as the dielectric constant. Preferably, the ratio ε.sub.r/k is in the range 0.743 (m.Math.K)/W≤ε.sub.r/kε194 (m.Math.K)/W. More preferably, the ratio ε.sub.r/k is in the range 1.133 (m.Math.K)/W≤ε.sub.r/k≤88.7 (m.Math.K)/W. At least one of the optical receiving fibers 120 and/or the transfer device 130 may have a relative permittivity in the range 1.02≤E.sub.r≤18.5, preferably in the range 1.02≤ε.sub.r≤14.5, more preferably in the range 1.02≤ε.sub.r≤8.7, wherein the relative permittivity is measured at 20° C. and 1 kHz. The optical receiving fibers 120 and/or the transfer device 130 may have a thermal conductivity of k≤24 W/(m.Math.K), preferably k≤17 W/(m.Math.K), more preferably k≤14 W/(m.Math.K). The optical receiving fibers 120 and/or the transfer device 130 may have a thermal conductivity of k≥0.003 W/(m.Math.K), preferably k≤0.007 W/(m.Math.K), more preferably k≤0.014 W/(m.Math.K). The thermal conductivity may be measured at 0° C. and <1% relative humidity.

[0257] The transfer device 130 may have a ratio v.sub.e/n.sub.D in the range 9.05≤v.sub.e/n.sub.D≤77.3, wherein v.sub.e is the Abbé-number and n.sub.D is the refractive index. The Abbé-number v.sub.e is given by

[00009] $v_{e} = \frac{(n_{D} - 1)}{(n_{F} - n_{c})},$

wherein n.sub.i is the refractive index for different wavelengths, wherein N.sub.C is the refractive index for 656 nm, n.sub.D is the refractive index for 589 nm and n.sub.F is the refractive index for 486 nm, measured at room temperature, see e.g. https://en.wikipedia.org/wiki/Abbe_number. Preferably, the ratio is in the range of 13.9≤v.sub.e/n.sub.D≤44.7, more preferably the ratio v.sub.e/n.sub.D in the range of 15.8≤v.sub.e/n.sub.D≤40.1.

[0258] Each of the optical receiving fibers 120 may comprise the at least one cladding 136 and the at least one core 134. A product αΔn may be in the range 0.0004 dB/km≤αΔn≤110 dB/km at at least one wavelength in a visual and near infrared wavelength range, wherein α the attenuation coefficient and Δn is the refractive index contrast with Δn=(n.sub.1.sup.2−n.sub.2.sup.2)/(2n.sub.1.sup.2), wherein n.sub.1 is the maximum core refractive index and n.sub.2 is the cladding refractive index. Preferably, the product αΔn is in the range 0.002 dB/km≤αΔn≤23 dB/km, more preferably in the range 0.02 dB/km≤αΔn≤11.26 dB/km. The refractive index contrast Δn may be in the range 0.0015≤Δn≤0.285, preferably in the range 0.002≤Δn≤0.2750, more preferably in the range 0.003≤Δn≤0.25. The attenuation coefficient of the optical receiving fibers 120 may be in the range 0.2 dB/km≤α≤420 dB/km, preferably in the range 0.25 dB/km≤α≤320 dB/km. The transfer device 130 may have an aperture area D.sub.1 and at least one of the optical receiving fibers 120 may be the fiber core 134 with a cross-sectional area D.sub.2, wherein a ratio D.sub.1/D.sub.2 is in the range 0.54≤D.sub.i/D.sub.2≤5087, preferably 1.27≤D.sub.1/D.sub.2≤413, more preferably 2.17≤D.sub.i/D.sub.2≤59.2. A diameter d.sub.core of the core 134 of at least one of the optical receiving fibers 120 may be in the range 2.5 μm≤d.sub.core≤10000 μm, preferably in the range 7 μm≤d.sub.core≤3000 μm, more preferably in the range 10 μm≤d.sub.core≤500 μm.

[0259] The optical receiving fibers 120 and/or the transfer device 130 may have a Youngs modulus, also denoted elastic modulus, of less or equal 188 GPa, measured at room temperature, for example by using ultrasonic testing. Preferably the optical receiving fibers 120 and/or the transfer device 130 may have a Youngs modulus of less or equal 167 GPa, more preferably in the range from to 0.0001 GPa to 97 GPa. The optical receiving fibers 120 and/or the transfer device 130 may have a Youngs modulus of greater or equal 0.0001 GPa, preferably of greater or equal 0.007 GPa, more preferably of greater or equal 0.053 GPa.

[0260] In FIG. 7, a schematic setup of the detector 112 for determining a position of the at least one object 114 is depicted. The detector 112 comprises the at least one transfer device 130. The transfer device 130 has at least one focal length in response to the at least one incident light beam propagating from the object 114 to the detector 110. The transfer device 130 has at least one optical axis 142.

[0261] The detector 112 comprises at least one illumination source 144 adapted to generate at least one light beam 146 for illuminating the object 114. Specifically, the illumination source 144 may comprise at least one light source such as at least one laser and/or laser source. Various types of lasers may be employed, such as semiconductor lasers. Additionally or alternatively, non-laser light sources may be used, such as LEDs and/or light bulbs. The illumination source 144 may comprise an artificial illumination source, in particular at least one laser source and/or at least one incandescent lamp and/or at least one semiconductor light source, for example, at least one light-emitting diode, in particular an organic and/or inorganic light-emitting diode. As an example, the light emitted by the illumination source 144 may have a wavelength of 300 to 1000 nm, especially 500 to 1000 nm. Additionally or alternatively, light in the infrared spectral range may be used, such as in the range of 780 nm to 3.0 μm. Specifically, the light in the part of the near infrared region where silicon photodiodes are applicable specifically in the range of 700 nm to 1000 nm may be used. Further, the illumination source 144 may be configured for emitting modulated or non-modulated light. In case a plurality of illumination sources 144 is used, the different illumination sources may have different modulation frequencies which later on may be used for distinguishing the light beams. The illumination source 144 may comprise the at least one optical sender fiber 118 adapted to transmit the light beam 146 generated by the light source such that it illuminates the object 112. The light beam 146 may leave the optical sender fiber 118 at an exit face of the optical sender fiber 118.

[0262] Preferably, the illumination source 144 may be configured to illuminate the object 144 under an angle α.sub.illu with respect to the optical axis. The angle α.sub.illu may be in the range 0°≤α.sub.illu≤40°, preferably α.sub.illu may be in the range 1°≤35°, more preferably α.sub.illu may be in the range 2°α.sub.illu≤25°. The illumination source 144, specifically an exit pupil of the illumination source 144, may be arranged under an arbitrary angle with respect to the optical axis 142. Illuminating the object 114 under an angle ≥5° with respect to the optical axis 142 may allow increasing the measurement range and enhancing resolution. Other embodiments, however, are feasible. For example, the illuminating light beam 146 may be parallel to the optical axis 142 or tilted with respect to the optical axis 142. As an example, the illuminating light beam 146 and the optical axis 146 may include an angle of less than 10°, preferably less than 5° or even less than 2°. Further, the illuminating light beam 146 may be on the optical axis 142 or off the optical axis 142. As an example, the illuminating light beam 146 may be parallel to the optical axis having a distance of less than 10 mm to the optical axis, preferably less than 5 mm to the optical axis or even less than 1 mm to the optical axis or may even coincide with the optical axis 142.

[0263] The illumination source 144 may have a geometrical extend Gin the range 1.5.Math.10.sup.−7 mm.sup.2.Math.sr≤G≤314 mm.sup.2.Math.sr, preferable in the range 1.Math.10.sup.−5 mm.sup.2.Math.sr≤G≤22 mm.sup.2.Math.sr, more preferable in the range 3.Math.10.sup.−4 mm.sup.2.Math.sr≤G≤3.3 mm.sup.2.Math.sr. The geometrical extent G of the illumination source 144 may be defined by

G=A.Math.Ω.Math.n.sup.2,

wherein A is the area of the surface, which can be an active emitting surface, a light valve, optical aperture or the area of the fiber core 134 with Δ.sub.OF=π.Math.r.sup.2.sub.OF, and Ω is the projected solid angle subtended by the light and n is the refractive index of the medium. For rotationally-symmetric optical systems with a half aperture angle θ, the geometrical extend is given by

G=π.Math.A.Math.sin.sup.2(θ)n.sup.2.

[0264] For optical fibers a divergence angle is obtained by θ.sub.max=arcsin(NA/n), where NA is the maximum numerical aperture of the optical fiber.

[0265] The detector 112 comprises the at least one first optical receiving fiber 122 and the at least one second optical receiving fiber 124. Each of the optical receiving fibers 120 may have at least one entrance face. A geometric center of the respective entrance face may be aligned perpendicular with respect to an optical axis 142 of the transfer device 130. At least one of the optical receiving fibers 120 may have an entrance face which is oriented towards the object 114. The optical receiving fibers 120 may be arranged in a direction of propagation of an incident light beam propagating from the object 114 to the detector 112 behind the transfer device 130. The optical receiving fibers 120 and the transfer device 130 may be arranged such that the light beam passes through the transfer device 130 before impinging on the optical receiving fibers 120. The optical receiving fibers 120 may be arranged as such, that the light beam impinges on the optical receiving fibers 120 between the transfer device 130 and the focal point of the transfer device 130. For example, a distance in a direction parallel to the optical axis 142 between the transfer device 130 and the position where the light beam impinges on the optical receiving fibers 120 may be at least 20% of the focal length, more preferably at least 50% of the focal length, most preferably at least 80% of the focal length. For example, the distance in a direction parallel to the optical axis 142 between the entrance face at least one of the optical receiving fibers 120 receiving the light beam and the transfer device 130 may be at least 20% of the focal length, more preferably at least 50% of the focal length, most preferably at least 80% of the focal length.

[0266] In the preferred setup, the entrance ends of the optical receiving fibers 120 may be positioned such that at an end of a required measurement range an image of the light spot is in focus or near focus and such that both optical receiving fibers 120 receive a similar amount of optical power.

[0267] The transfer device 130 may comprise at least one gradient index (GRIN) lens. The transfer device 130 and the optical receiving fibers 120 may be configured as one-piece. The optical receiving fibers 120 may be attached to the transfer device 130 such as by a polymer or glue or the like, to reduce reflections at interfaces with larger differences in refractive index.

[0268] The detector 112 may comprise a baseline. The exit pupil of the illumination source 144 may be displaced from the optical axis 142 in a first direction by the distance BL. The optical receiving fibers 120, specifically a centroid of the entrance faces of the optical receiving fibers 120, may be displaced from the optical axis 142 in a second direction, in particular different to the first direction, by the distance d.sub.R. The first optical receiving fiber 122 has a core diameter of d.sub.1. The second optical receiving fiber 124 has a core diameter of d.sub.2. A ratio d.sub.1/BL is in the range 0.000047≤d.sub.1/BL≤313 and/or a ratio d.sub.2/BL is in the range 0.000047≤d.sub.2/BL≤313. Preferably the ratio d.sub.1/BL is in the range 0.000114≤d.sub.1/BL≤30.37, preferably in the range 0.000318≤d.sub.1/BL≤6.83, and/or wherein the ratio d.sub.2/BL is in the range 0.000114≤d.sub.2/BL≤30.37, more preferably in the range 0.000318≤d.sub.2/BL≤6.83. The displacement of the illumination source 144 from the optical axis 142 may have an extent greater than 0. The displacement of the illumination source 144 from the optical axis 142 may be in the range 10 μm≤BL≤127000 μm, preferably in the range 100 μm≤BL≤76200 μm, more preferably in the range 500 μm≤BL≤25400 μm. For example, core diameters may range from 1 μm to 5 mm such that a minimal baseline may be 1 μm. A maximum baseline may be defined as 2 m. By adequately setting the ratio of the displacement (BL) and the receiving fiber core diameters (d.sub.1 and d.sub.2) the measurement range and the resolution can be adjusted depending on the measurement application. In this example a ratio of d.sub.1/BL may be 0.0000005≤d.sub.1/BL≤1 and/or a ratio of d.sub.2/BL may be 0.0000005≤d.sub.2/BL≤1. Preferably the ratio d.sub.1/BL may be 0.000114≤d.sub.1/BL≤0.8, more preferably the ratio d.sub.1/BL may be 0.000318≤d.sub.1/BL≤0.5. Preferably, the ratio d.sub.2/BL may be 0.000114≤d.sub.2/BL≤0.8, more preferably 0.000318≤d.sub.2/BL≤0.5. A displacement of the exit pupil of the illumination source 144 from the optical axis may allow increasing the measurement range and enhancing resolution. Each of the optical receiving fibers 120 may comprise the at least one entrance face. A centroid of the entrance faces of the first and second optical receiving fibers may be displaced from the optical axis by the distance d.sub.R. The distance d.sub.R may be in the range 10 μm≤d.sub.R≤127000 μm, preferably in the range 100 μm≤d.sub.R≤76200 μm, more preferably in the range 500 μm≤d.sub.R≤25400 μm. Thus, the illumination source 144 and/or the exit face of the optical sender fiber 118 and the entrance face of one or both of the optical receiving fibers 120 may be arranged with a relative spatial offset from the optical axis 142 of the transfer device 130. In particular, the illumination source 144 and/or the exit face of the optical sender fiber 118 and the entrance face of one or both of the optical receiving fibers 120 may be arranged with different spatial offsets from the optical axis 142. Such an arrangement may allow enhancing the tendency of the combined signal Q, and thus, accuracy of the distance measurement. In particular, with increasing spatial offset a slope in a Q vs distance diagram increases and thus allows distinguishing similar distances more accurately. For example, one of the illumination source 144 and the entrance face of one or both of the optical receiving fibers 120 may be arranged on the optical axis 142 and the other one may be arranged spaced apart from the optical axis 142. For example, both of illumination source 144 and the entrance face of one or both of the optical receiving fibers 120 may be arranged spaced apart from the optical axis 142 by at least one different distance, in particular perpendicular to the optical axis 142. For example, the at least two optical receiving fibers 120 may be arranged at different distances from the optical axis 142. The optical receiving fibers 120 may be adapted to mimic a larger distance compared to the real distance perpendicular to an optical axis 142 between the illumination source 144 and the optical sensors 126, 128 without moving the illumination source 144 and/or optical sensors 126, 128.

[0269] The detector comprises at least two optical sensors 126, 128, wherein at least one first optical sensor 126 is arranged at an exit end of the first optical receiving fiber 122 and at least one second optical sensor 128 is arranged at an exit end of the second optical receiving fiber 124. Each optical sensor has at least one light sensitive area 148. The first optical receiving fiber 122 may be arranged and configured to provide light to the first optical sensor 126 and the second optical receiving fiber 124 may be arranged and configured to provide light to the second optical sensor 128. This is schematically shown with two arrows pointing to the optical sensors 126, 128 in FIG. 7. Each optical sensor 126, 128 is designed to generate at least one sensor signal in response to an illumination of its respective light-sensitive area 148 by a light beam having passed through the respective optical receiving fiber 122, 124.

[0270] The detector 112 comprises at least one evaluation device 150 being configured for determining at least one longitudinal coordinate z of the object 114 by evaluating a combined signal Q from the sensor signals. The first optical sensor 126, in response to the illumination by the light beam, may generate a first sensor signal s.sub.1, whereas the second optical sensor 128 may generate a second sensor signal 52. Preferably, the optical sensors 126, 128 are linear optical sensors. The sensor signals s.sub.1 and s.sub.2 are provided to the evaluation device 150. The evaluation device 150 is embodied to derive a combined signal Q from the sensor signal, specifically by evaluating a quotient signal. From the combined signal Q, derived by dividing the sensor signals s.sub.1 and s.sub.2 or multiples or linear combinations thereof, may be used for deriving at least one item of information on a longitudinal coordinate z of the object 114. The evaluation device 150 may have at least one divider 152 for forming the combined signal Q, and, as an example, at least one position evaluation device 154, for deriving the at least one longitudinal coordinate z from the combined signal Q. It shall be noted that the evaluation device 150 may fully or partially be embodied in hardware and/or software. Thus, as an example, one or more of components 152, 154 may be embodied by appropriate software components.

[0271] FIG. 8 shows experimental results of distance measurements. The employed measurement head 110 comprises two optical receiving fiber 120 including entrance ends and one optical sender fiber 118 including exit end and including the corresponding fiber cores 134 with identical diameters of 500 μm are aligned and centered horizontally in comparable to the setup in FIG. 1D, wherein the entrance ends of the two optical receiving fibers 120 are positioned directly adjacent to each other, whereas the centroid of the exit end of the optical sender fiber 118 has a distance of 3.4 mm to the centroid of both optical receiving fiber entrance ends, which corresponds to the baseline. As a transfer device 130, an aspherical lens with a diameter of 3 mm collimated the light beams 146 coming out of the exit end of the optical sender fiber 118, whereas the transfer device 130 is positioned in a focal distance of 2 mm of the exit end of the optical sender fiber 118. An identical transfer device 130 in front of the two receiving ends of the optical receiving fibers 120 collects the light beams 146 reflected from a target. Since the entrance ends of the optical receiving fibers 120 are positioned nearer to the transfer device 130 than its focal length, the generated image on the entrance ends of the optical receiving fibers 120 is out of focus. The entrance end of the optical sender fiber 118 is connected to a LED with a central wavelength of 635 nm, while the exit ends of the optical receiving fibers 120 are connected to silicon photodiodes. The determined combined signal Q is shown as a function of the real object distance zreal in mm. Three different targets were tested, in particular a black paper object (curve 156, dotted line), a white paper object (curve 158, dashed line) and a metallic surface (curve 160, dashed dotted line). The white paper target used in this experiment yields a reflectivity of 84% at the given wavelength, while the black paper target yields only 10% reflectivity. As metallic surface, an aluminum sheeting with brushed surface is employed. A great reliability independent on the target reflectivity and material is observed. The curve with black paper target shows strong noise due to low signal intensity. The noise may be reduced by introducing automatic gain control in the analog front-end of the receiving electronics or an automated adaption of the illumination intensity.

LIST OF REFERENCE NUMBERS

[0272] 110 measurement head [0273] 112 Detector [0274] 114 Object [0275] 116 Housing [0276] 118 optical sender fiber [0277] 120 optical receiving fiber [0278] 122 1. optical receiving fiber [0279] 124 2. optical receiving fiber [0280] 126 1. optical sensor [0281] 128 2. optical sensor [0282] 130 transfer device [0283] 132 spacer device [0284] 134 core [0285] 136 cladding [0286] 138 buffer [0287] 140 jacket [0288] 142 optical axis [0289] 144 Illumination source [0290] 146 light beam [0291] 148 light sensitive area [0292] 150 evaluation device [0293] 152 divider [0294] 154 position evaluation device [0295] 156 curve [0296] 158 curve [0297] 160 curve

DETECTOR FOR DETERMINING A POSITION OF AT LEAST ONE OBJECT

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Cpc classification

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G02B6/02

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G02B6/262

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G01B1/00

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G01B11/24

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G01B11/002

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International classification

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G01B11/00

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G02B6/02

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Abstract

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