Sensor for detecting an object in an external environment of the sensor

Abstract

The invention relates to a sensor (50a) comprising a first optical meta-element (4) and an interferometer unit (56). The interferometry unit (56) is designed to emit a first light beam or a second light beam (54a) and a third light beam (54b) in the direction of the optical meta-element (4). The first optical meta-element (4) is used to deflect a first part of the first light beam incident on the first optical meta-element (4) from a first polarization direction with a first optical function, and to deflect a second part of the first light beam incident on the first optical meta-element (4) from a second polarization direction with a second optical function different from the first optical function. Alternatively, the first optical meta-element is used to deflect the second light beam (54a) incident from a third polarization direction with a third optical function and to deflect the third light beam (54b), which arrives from a fourth polarization direction different from the third polarization direction, with a fourth optical function different from the third optical function. The interferometer unit (56) is designed to receive the first and second parts of the first light beam backscattered off the object (52) or the second light beam (54a) and third light beam (54b) backscattered off the object (52).

Description

[0001] R.418016

[0002] - 1 -

[0003] Description

[0004] Sensor for detecting an object in an external environment of the sensor

[0005] The invention relates to a sensor for detecting an object in an external environment of the sensor.

[0006] State of the art

[0007] A laser feedback interferometry sensor for environmental sensing is known.

[0008] Based on this, it is an object of the present invention to develop a sensor that detects objects in an external environment of the sensor more reliably.

[0009] Disclosure of the invention

[0010] To solve the problem, a sensor for detecting an object in an external environment of the sensor according to claim 1 is proposed. The sensor comprises a first optical metaelement and an interferometer unit. The interferometer unit is configured to emit a first light beam, in particular a first laser beam, in the direction of the optical metaelement. In this context, the first optical metaelement serves to deflect a first part of the first light beam, which strikes the first optical metaelement with a first polarization direction and has a first optical function, and a second part of the first light beam, which strikes the first optical metaelement with a second polarization direction and has a second optical function different from the first.The interferometer unit is further designed to detect the first and second part of the first light scattered back from the object, which is arranged behind the first optical metaelement, particularly relative to the interferometer unit. R.418016.

[0011] - 2 -

[0012] to receive beams. Alternatively, the interferometer unit is configured to emit a second light beam, in particular a second laser beam, and a third light beam, in particular a third laser beam, which is parallel to the second light beam, in the direction of the optical metaelement. In this context, the first optical metaelement serves to deflect the second light beam, which arrives at the first optical metaelement with a third polarization direction, with a third optical function, and the third light beam, which arrives with a fourth polarization direction different from the third, with a fourth optical function different from the third. The interferometer unit is further configured to receive the second and third light beams backscattered by the object.The use of different polarization directions of the light rays has the advantage that the first optical meta-element can transmit different optical functions and thus objects in the external environment can be detected from different perspectives.

[0013] Preferably, the interferometer unit, in conjunction with the previously mentioned alternative, comprises only a first interferometer. The sensor includes a polarizing first output coupling element, in particular a second optical meta-element. The polarizing first output coupling element is arranged between the interferometer and the first optical meta-element and has a first region and a second region, such that the first light beam incident on the polarizing first output coupling element is split into the first and second parts of the first light beam. The first region is specifically designed as a circular central region, and the second region as a region surrounding the central region. This design has the advantage that only one interferometer, and consequently few resources, are required for its implementation.

[0014] Preferably, the interferometer unit, in conjunction with the alternative mentioned second above, comprises a second interferometer configured to emit the second light beam. Furthermore, the interferometer unit comprises a third interferometer configured to emit the third light beam. The use of two interferometers is described in R.418016.

[0015] - 3 -

[0016] The advantage is that, due to the correspondingly coherent measurement method, there is no risk of crosstalk between light signals. Preferably, the second and third interferometers are arranged on a common substrate. This saves space and resources. The substrate is preferably a silicon substrate. Alternatively, the substrate can also be an ASIC. Preferably, the second and third interferometers are arranged in a common housing. In this context, the second and third interferometers, especially together with the common substrate, are arranged on a housing base, and the first optical metamaterial is arranged on a side of the housing opposite the housing base. This offers the advantage of arranging the two sensors in a single package, thus saving space.

[0017] Preferably, the second and third interferometers are arranged rotated relative to each other such that a third polarization direction and a fourth polarization direction that differs from the third, in particular by 90°, are generated. Alternatively, a second exit facet, in particular a mesa, belonging to the second interferometer, and a third exit facet, in particular a mesa, belonging to the third interferometer, are configured such that a third polarization direction and a fourth polarization direction that differs from the third, in particular by 90°, are generated. Alternatively, the sensor also includes a polarizing second output coupling element, in particular a third optical meta-element, for changing the polarization direction of the second or third light beam. The polarizing second output coupling element is arranged between the second or third interferometer and the first optical meta-element.Preferably, in this context, the second output coupling element is connected to the second or third interferometer. In particular, the second output coupling element is integrally connected to the second or third interferometer. This also saves space. Specifically, the second output coupling element is manufactured on the wafer level together with the second or third interferometer.

[0018] Preferably, the first, second, and / or third interferometers are configured as laser feedback interferometry sensors. In this context, R.418016

[0019] - 4 -

[0020] The LFI sensor is specifically designed to detect the object based on a voltage measurement of a laser diode associated with the LFI sensor. Alternatively, the LFI sensor has a separate photodiode integrated into the laser cavity for object detection. As an alternative to the laser feedback interferometry sensors, the first, second, and / or third interferometers have photodiodes with polarization filters for receiving the respective backscattered light signals.

[0021] Preferably, the first optical metaelement is configured to deflect the light rays in such a way that they overlap, at least partially, particularly behind the optical metaelement. The coherent measurement principle allows for this overlap of light rays, enabling the detection of an ambient area by multiple light rays. This, in turn, allows for a wide variety of optical applications. For example, it can enable a camera function where one light beam is used for illumination and the other for object detection.

[0022] Preferably, the first optical meta-element is configured to deflect the light rays in such a way that a pattern, in particular a grid, is generated on a common plane, especially a focal plane. The pattern is particularly cross-shaped. Thus, the object can be detected three-dimensionally.

[0023] Preferably, the sensor is designed to detect the distance of the object relative to the sensor and is therefore configured as a distance sensor. However, the sensor is also specifically designed to detect changes in distance and is therefore configured as a velocity sensor. Furthermore, the sensor is also designed to detect the acceleration of the object.

[0024] Preferably, the sensor additionally includes a processing unit with two analog multiplexers for simultaneous or sequentially staggered control of the second and third interferometers. This offers the advantage that only one receiver is required for the light signals with different polarization directions. R.418016

[0025] - 5 -

[0026] Preferably, the different optical functions, in particular the first and second or the third and fourth optical functions, are arranged side by side on the first optical meta-element. Alternatively, the different optical functions, in particular the first and second or the third and fourth optical functions, are arranged one above the other on the first optical meta-element.

[0027] Description of the drawings

[0028] Figure 1 shows a first embodiment of a sensor for detecting an object in an external environment of the sensor.

[0029] Figure 2 shows a second embodiment of a sensor for detecting an object in an external environment of the sensor.

[0030] Figure 3 shows a third embodiment of a sensor for detecting an object in an external environment of the sensor.

[0031] Figure 4 shows one way to generate light rays with different polarization directions.

[0032] Figure 5 shows another possibility for generating light rays with different polarization directions.

[0033] Description of the exemplary implementations

[0034] Figure 1 schematically shows a first embodiment of a sensor 50a for detecting an object 52 in an external environment of the sensor 50a. The sensor 50a is configured for distance detection, in particular for detecting a change in the distance of the object 52. The sensor 50a comprises a first optical metaelement 4 and an interferometer unit 56. The interferometer unit 56 is configured to emit a second light beam 54a and a third light beam 54b, which is in particular parallel to the second light beam 54a, in the direction of the optical metaelement 4. The first optical metaelement 4 is configured to detect the second light beam 54a.

[0035] - 6 -

[0036] The interferometer unit 56 is configured to deflect the first optical metaelement 4, the light beam 54a arriving with a third polarization direction 55a, with a third optical function, and the third light beam 54b, arriving with a fourth polarization direction different from the third, with a fourth optical function different from the third. Furthermore, the interferometer unit 56 is configured to receive the second light beam 54a and the third light beam 54b backscattered by the object 52.

[0037] In this first embodiment of the sensor 50a, the interferometer unit 56 comprises a second interferometer 8, which is configured to emit the second light beam 54a. Furthermore, the interferometer unit 56 comprises a third interferometer 6, which is configured to emit the third light beam 54b. The second interferometer 8 and the third interferometer 6 are arranged on a common support substrate 9. Furthermore, the second interferometer 8 and the third interferometer 6 are arranged in a common housing 3. Here, the second interferometer 8 and the third interferometer 6 are arranged on the support substrate 9 as the housing base, and the first optical metamaterial 4 is arranged on a side of the housing 3 opposite the housing base.The second interferometer 8 and the third interferometer 6 are arranged rotated relative to each other such that the third polarization direction 7 is aligned in a horizontal direction and the fourth polarization direction 5 is offset by 90° to this in a vertical direction.

[0038] In this first embodiment of the sensor 50a, the second interferometer 8 and the third interferometer 6 are designed as laser feedback interferometry sensors.

[0039] The first optical meta-element 4 is configured to deflect the second 54a and third light rays 54b such that a cross-shaped pattern 51 is generated on a common plane, in particular the focal plane. This allows the object 52 to be detected three-dimensionally. In this embodiment of the first optical meta-element 4, the third and fourth optical functions are arranged one above the other on the first optical meta-element 4. Alternatively, the different optical functions can also be arranged side by side on the first optical meta-element 4. R.418016

[0040] - 7 -

[0041] In this first embodiment of the sensor 50a, the sensor 50a is wired to a circuit board 10 58. Furthermore, the sensor 50a has a processing unit 60 with two analog multiplexers 63a and 63b for simultaneous or sequentially controlling the second 8 and third interferometers 6. The processing unit 60 also has a laser driver 61 and a first receiver 62. In addition, the processing unit 60 has a second receiver 64a assigned to the second laser diode 65a of the second interferometer 8 and a third receiver 64b assigned to the third laser diode 65b of the third interferometer 6.

[0042] Figure 2 shows a second embodiment of a sensor 50b for detecting an object in the sensor's external environment. In contrast to the first embodiment, the first optical metaelement 4 is configured to deflect the third light beam 1 with the fourth polarization direction 5 using a third optical function such that the third light beam 1 illuminates the sensor's external environment. The first optical metaelement 4 deflects the second light beam 2 using the second optical function such that a camera function is created. The first optical metaelement 4 serves to deflect the light beams 1 and 2 such that they overlap, at least partially, particularly behind the optical metaelement 4.

[0043] Figure 3 shows a third embodiment of a sensor 50c for detecting an object in an external environment of the sensor 50c. In contrast to the embodiments described above, the interferometer unit 78 here comprises only a first interferometer (not shown for the sake of simplicity), which is configured to emit a first light beam 76. The first optical metaelement 73 is configured to deflect a first part 72a of the first light beam 76, which strikes the first optical metaelement 73 with a first polarization direction and has a first optical function, and a second part 72b of the first light beam 76, which strikes the first optical metaelement 73 with a second polarization direction and has a second optical function different from the first, towards a first focal point 74a and a second focal point 74b.The interferometer unit 78 is designed to measure the radiation relative to the interferometer R.418016.

[0044] - 8 -

[0045] ter- Unit 78 behind the first optical metaelement 73 arranged object 77 to receive the first part 72a and second part 72b of the first light beam 76 scattered back.

[0046] In this third embodiment, the sensor 50c has a polarizing first output coupling element 71 in the form of a second optical metaelement. The polarizing first output coupling element 71 is arranged between the interferometer unit 78 and the first optical metaelement 73 and has a first, circular central region 70a and a second region 70b surrounding the first central region 70a, such that the first light beam 76 incident on the polarizing first output coupling element 71 is split into the first part 72a and the second part 72b of the first light beam 76.

[0047] Figure 4 schematically shows a possibility for generating light beams of different polarization directions in a top view of the interferometer unit 17. Here, a second exit facet 15, in particular a mesa, belonging to the second interferometer, and a third exit facet 16, in particular a mesa, belonging to the third interferometer, are designed or shaped such that the third polarization direction 13 is rotated by 90° relative to the fourth polarization direction 14.

[0048] Figure 5 schematically shows another possibility for generating light beams with different polarization directions. Here, the sensor's interferometer unit 34 has a polarizing second output coupling element 35 in the form of a third optical meta-element for changing the fourth polarization direction of the third light beam. The second output coupling element 35 changes the fourth polarization direction of the third light beam from a horizontal direction 33 to a vertical direction 36. The third polarization direction of the second interferometer 31 remains in the horizontal direction 32. In this embodiment, the second output coupling element 35 is integrally connected to the third interferometer 37.

Claims

R.418016 - 9 - Claims 1. Sensor (50a, 50b, 50c) for detecting an object (52) in an external environment of the sensor (50a, 50b, 50c), comprising - a first optical meta-element (4, 73), and - an interferometer unit (34, 56, 78), wherein the interferometer unit (34, 56, 78) is designed to - to emit a first beam of light (76), - or to emit a second light ray (2, 54a) and a third light ray (1, 54b), in particular parallel to the second light ray (2, 54a), in the direction of the first optical metaelement (4, 73), wherein the first optical metaelement (4, 73) is designed to, - a first part (72a) of the first light ray (76) striking the first optical metaelement (4, 73) with a first polarization direction and having a first optical function, and a second part (72b) of the first light ray (76) striking the first optical metaelement (4, 73) with a second polarization direction and having a second optical function different from the first, or - the second light ray (2, 54a) striking the first optical metaelement (4, 73) with a third polarization direction (7, 13) and a third optical function, and the third light ray (1, 54b) arriving with a fourth polarization direction (5, 14) different from the third and a fourth optical function different from the third to redirect, , wherein the interferometer unit (34, 56, 78) is designed to, - the one located, in particular relative to the interferometer unit (34, 56, 78) behind the first optical metaelement (4, 73) - R.418016 - 10 - ordered, object (52) backscattered first (72a) and second part (72b) of the first light ray (76), or - the second (2, 54a) and third light rays (1, 54b) scattered back from the object (52) to receive.

2. Sensor (50a, 50b, 50c) according to claim 1, characterized in that the interferometer unit (34, 56, 78) comprises only a first interferometer, wherein the sensor (50a, 50b, 50c) comprises a polarizing first output coupling element (71), in particular a second optical meta-element, wherein the polarizing first output coupling element (71) is arranged between the first interferometer and the first optical meta-element (4, 73) and comprises a first region (70a), in particular a circular central region, and a second region (70b), in particular a region surrounding the central region, such that the first light beam (76) incident on the polarizing first output coupling element (71) is split into the first (72a) and second part (72b) of the first light beam (76).

3. Sensor (50a, 50b, 50c) according to claim 1 , characterized in that the interferometer unit (34, 56, 78) comprises a second interferometer (8, 31) configured to emit the second light beam (2, 54a) and a third interferometer (6, 37) configured to emit the third light beam (1 , 54b).

4. Sensor (50a, 50b, 50c) according to claim 3, characterized in that the second (8, 31) and third interferometer (6, 37) are arranged on a common support substrate (9).

5. Sensor (50a, 50b, 50c) according to one of claims 3 or 4, characterized in that the second (8, 31) and third interferometer (6, 37) are arranged in a common housing (3), wherein the second (8, 31) and third interferometer (6, 37), in particular together with the common support substrate (9), are mounted on a housing base and the first - 11 - optical metamaterial (4, 73) is arranged on a side of the housing (3) opposite the housing bottom.

6. Sensor (50a, 50b, 50c) according to one of claims 3 to 5, characterized in that the second (8, 31) and third interferometer (6, 37) are arranged rotated relative to each other such that the third (7, 13) and fourth polarization directions (5, 14) are generated that are different from the third, in particular by 90°.

7. Sensor (50a, 50b, 50c) according to one of claims 3 to 5, characterized in that a second exit facet (15), in particular mesa, belonging to the second interferometer (8, 31), and a third exit facet (16), in particular mesa, belonging to the third interferometer (6, 37), are configured such that the third (7, 13) and a fourth polarization direction (5, 14) that differs from the third, in particular by 90°, are generated.

8. Sensor (50a, 50b, 50c) according to one of claims 3 to 5, characterized in that the sensor (50a, 50b, 50c) has a polarizing second output coupling element (35), in particular a third optical meta-element, for changing the polarization direction of the second (2, 54a) or third light beam (1, 54b), wherein the polarizing second output coupling element (35) is arranged between the second (8, 31) or third interferometer (6, 37) and the first optical meta-element (4, 73).

9. Sensor (50a, 50b, 50c) according to claim 8, characterized in that the second coupling element (35) is connected, in particular in one piece, to the second (8, 31) or third interferometer (6, 37).

10. Sensor (50a, 50b, 50c) according to one of claims 2 to 9, characterized in that the first, second (8, 31) and / or third interferometer (6, 37) are designed as laser feedback interferometry sensors.

11. Sensor (50a, 50b, 50c) according to one of claims 1 to, 10, characterized in that the first optical metaelement (4, 73) is designed to-R.418016 - 12 - The purpose is to redirect the light rays (1 , 2, 54a, 54b, 76) in such a way that they overlap, at least partially, especially behind the first optical meta-element (4, 73).

12. Sensor (50a, 50b, 50c) according to one of claims 1 to 11, characterized in that the first optical metaelement (50a, 50b, 50c) is configured to deflect the light rays (1, 2, 54a, 54b, 76) in such a way that a pattern (51), in particular a grid, is generated on a common plane, in particular a focal plane, in particular a cross-shaped pattern (51).

13. Sensor (50a, 50b, 50c) according to one of claims 1 to 12, characterized in that the sensor (50a, 50b, 50c) is configured for distance detection, in particular for detection of a change in the distance of the object (52).

14. Sensor (50a, 50b, 50c) according to one of claims 2 to 13, characterized in that the sensor (50a, 50b, 50c) additionally has a computing unit (60) with two analog multiplexers (63a, 63b) for simultaneous or time-shifted control of the second (8, 31) and third interferometer (6, 37).

15. Sensor (50a, 50b, 50c) according to one of claims 1 to 14, characterized in that the different optical functions, in particular the first and second or the third and fourth optical functions, are arranged next to each other or one above the other on the first optical metaelement (4, 73).

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