DETECTION UNIT AND DETECTION MODULE

Abstract

A detection unit (10) for determining at least one property of an external object (O) is specified, wherein the detection unit (10) is intended for self-mixing interferometry (SMI) and comprises: - a laser radiation source (1) designed to emit laser radiation (S1) and comprising an optical resonator (9A, 9B), - a detector component (2) which is arranged adjacent to the laser radiation source (1) and is intended for the detection of interference radiation, - a housing component (3) that laterally surrounds the laser radiation source (1) and the detector component (2), and - an optical element (6) covering the laser radiation source (1) and the detector component (2) and designed to provide a part (S1 r) of an interference radiation which arises in the optical resonator (9A, 9B) by interference of the laser radiation (S1) from the laser radiation source (1) and deflected laser radiation (S2) from the external object (O), to the detector component (2), wherein the optical element (6) deflects the part directed towards the detector component (2) (S1) r ) the interference radiation is influenced in such a way that it is higher than without the optical element (6). Furthermore, a detection module with at least two detection units is specified.

Description

[0001] A detection unit and a detection module are specified, the detection module comprising at least two detection units. The detection unit and the detection module are suitable for determining at least one property of an external object, such as its distance, velocity, or eye movement. In particular, the detection module is suitable as a power readout module.

[0002] For example, there are detectors that incorporate a VCSEL (Vertical Cavity Surface Emitting Laser) with an integrated photodiode, utilizing self-mixing interference (SMI). The problem with these detectors is that a detection signal cannot be maximized without compromising the integrity of the VCSEL signal. This makes it difficult to integrate these detectors into applications requiring multi-point measurement using multiple detectors, as the detection signal, which can be affected by crosstalk between the multiple detectors, is barely distinguishable.

[0003] One objective is to specify a detection unit with an improved detection signal. This objective is achieved, among other things, by the detection unit according to the independent claim.

[0004] Another task is to specify a detection module with improved detection signals. This task is solved, among other things, by the detection module according to the independent claim.

[0005] Further embodiments and developments of the detection unit or detection module are the subject of the dependent claims.

[0006] According to at least one embodiment of a detection unit, the detection unit is designed to determine at least one property of an external object. This property can be the distance, speed, or eye movement of the external object, where the term "object" also includes living beings or parts of living beings. For example, the external object is an eye whose position, gaze direction, gaze path, gaze speed, corneal displacement, and / or orientation are to be tracked.

[0007] According to at least one embodiment, the detection unit comprises a laser radiation source. In particular, the laser radiation source emits electromagnetic laser radiation during operation. For example, the laser radiation source comprises an optical resonator. An active zone of the laser radiation source can be arranged within the optical resonator. The electromagnetic laser radiation can have a peak wavelength in the visible to infrared spectral range, wherein the peak wavelength denotes a maximum of a spectral distribution of the electromagnetic laser radiation.

[0008] According to at least one embodiment, the detection unit comprises a detector component designed to detect interference radiation. The detection component can be located adjacent to the laser radiation source. The detector component can be positioned at a lateral distance from the laser radiation source. Additionally, the detector component can be positioned at a vertical distance from the laser radiation source. While the lateral distance can be determined along a horizontal plane, the vertical distance can be determined along a vertical direction that is oblique, for example, perpendicular, to the horizontal plane.

[0009] In particular, the detector component is a separate component that is not integrated into the laser radiation source. Separating the detector component from the laser radiation source has the advantage that the radiation to be detected by the detector component can be influenced without disturbing the integrity of the radiation or the signal from the laser radiation source.

[0010] According to at least one embodiment, the detection unit is designed for self-mixing interferometry. In general, self-mixing interferometry (SMI) involves the detection of interference radiation resulting from the interaction of laser radiation from the laser source with deflected laser radiation from the external object. For example, the amplitude, phase, and / or frequency of the emitted laser radiation is altered due to self-mixing interference. This altered amplitude, phase, and / or frequency of the interference radiation can then be used to determine at least one property of the external object. Due to the coherence length of the laser source, the working range of the SMI detection unit can be at least five meters.

[0011] According to at least one embodiment, the detection unit comprises a housing component. The housing component can laterally surround the laser radiation source and the detector component. In the context of the present application, "lateral" can denote lateral directions arranged in a horizontal plane. The laser radiation source and the detector component can be arranged in a cavity of the housing component.

[0012] According to at least one embodiment, the detection unit comprises an optical element. Preferably, the optical element is partially transparent to the radiation emitted and detected by the detection unit. Suitable materials for the optical element are, for example, glass and / or plastic materials.

[0013] According to at least one embodiment, the optical element covers the laser radiation source and the detector component. The optical element can close off an upper part of the cavity of the housing component in which the laser radiation source and the detector component may be arranged.

[0014] According to at least one embodiment, the optical element is designed to deflect part of the interference radiation, which arises in the optical resonator from the interference of the laser radiation from the laser radiation source and deflected laser radiation from the external object, to the detector component, which means, for example, reflection and / or refraction.

[0015] According to at least one embodiment, the optical element influences the portion of the interference radiation directed at the detector component such that it is stronger than it would be without the optical element. Thus, the optical element can improve the detection signal at the detector component.

[0016] According to at least one embodiment of a detection unit for determining at least one property of an external object, the detection unit is designed for self-mixing interferometry and comprises: - a laser radiation source designed to emit laser radiation and comprising an optical resonator, - a detector component that is located adjacent to the laser radiation source and is intended for the detection of interference radiation, - a housing component that laterally surrounds the laser radiation source and the detector component, and - an optical element covering the laser radiation source and the detector component, designed to deflect part of the interference radiation, which arises in the optical resonator from the interference of the laser radiation from the laser radiation source and deflected laser radiation from the external object, to the detector component, wherein the optical element influences the part of the interference radiation directed towards the detector component in such a way that it is higher than it would be without the optical element.

[0017] According to at least one embodiment or configuration, the detection unit comprises a carrier component on which at least one of the laser radiation source and the detector component is mounted. The housing component may be connected to the carrier component.

[0018] According to at least one embodiment or configuration, the optical element comprises at least one planar surface, and this planar surface has a surface normal with an orientation other than a principal emission direction of the laser radiation source. For example, the planar surface is inclined to a principal extension plane of the detection unit. The principal extension plane can be a horizontal plane. And the principal emission direction can be inclined, for example, perpendicular, to the principal extension plane. In the context of the present application, the principal emission direction can define a direction in which an intensity distribution of the electromagnetic laser radiation exhibits its maximum.

[0019] According to at least one embodiment or configuration, the optical element has a planar or plate-like shape and is tilted with respect to the principal extension plane of the detection unit. In particular, in this embodiment or configuration, the optical element is free of optical structures such as optical gratings and / or variations in refractive index. By tilting the optical element, the radiation projected by the optical element onto the detector component can be optimized, along with the height and base area of ​​the detection unit. Optimizing the projected radiation includes, for example, reducing the divergence of the projected radiation and / or changing the principal emission direction of the projected radiation relative to the principal emission direction of the laser radiation source.

[0020] According to at least one embodiment or configuration, the optical element, which has a planar shape, is inclined at an acute angle of inclination that deviates from 45°. In particular, the acute angle of inclination is less than 45°. In this embodiment or configuration, the laser radiation source and the detector component can be mounted on a surface of the support component. Furthermore, the laser radiation source and the detector component can be separated only by a lateral distance and can be easily assembled.

[0021] According to at least one embodiment or configuration, the optical element, which has a planar shape, is inclined at an angle of 45°. In this embodiment or configuration, the optical element can be a beam splitter. Furthermore, while one of the laser radiation source and the detector component can be mounted on a surface of the support component, the other can be mounted on a side wall of the housing component. In this embodiment or configuration, the laser radiation source and the detector component can be separated laterally as well as vertically. Although the assembly is more complex in this embodiment or configuration, the detection unit offers a high signal-to-noise ratio (SNR), good immunity to external light sources, and a small footprint.

[0022] According to at least one embodiment or configuration, the optical element, which comprises at least one planar surface, is a waveguide. The laser radiation source and the detection component can be arranged within the waveguide. Advantageously, the height of the detection unit can be minimized in this embodiment or configuration. Furthermore, it is possible to implement the waveguide at the wafer level, which simplifies the manufacturing process of the detection unit or detection module.

[0023] According to at least one embodiment or configuration, the optical element has a curved surface. The curved surface can be approximated by a plurality of differently inclined regions. Thus, as mentioned above, the radiation projected onto the detector component can be optimized by the optical element together with the height and base area of ​​the detection unit. In particular, the radiation projected onto the detector component can be focused by the optical element, which has a curved surface. In this embodiment or configuration, the optical element can have a curved shape resembling a portion of a spherical or ellipsoidal surface. Alternatively, the optical element can be a waveguide as mentioned above, but with a curved surface instead of the flat surface(s).

[0024] According to at least one embodiment or configuration, the optical element is a diffractive optical element. The optical element can, for example, comprise a volume phase hologram. In this embodiment or configuration, the optical element can have a planar or plate-like shape and be horizontally oriented so that the optical element is not tilted with respect to a principal extension plane of the detection unit or detection module. Advantageously, this results in an even lower height of the unit or module compared to an optical element that is tilted.

[0025] According to at least one embodiment or configuration, the laser radiation source is a single laser diode. For example, the laser diode is a single VCSEL emitter.

[0026] According to at least one embodiment or configuration, the laser radiation source comprises an array of laser diodes, for example, an array of VCSELs. For instance, the laser diodes can be operated sequentially. Time-division multiplexing can be used to drive a single laser diode at a time. The detection signal read out at the detector component originates from a single laser diode at any given time. This embodiment or configuration allows the unit, or the module composed of more than one unit, to have reduced power consumption and a smaller footprint, since one detector component is sufficient for multiple laser diodes.

[0027] Suitable materials for the laser diode(s) include, for example, semiconductor materials based on arsenide, phosphide or nitride compound semiconductors.

[0028] According to at least one embodiment or configuration, the detector component is a photodiode. Suitable materials for the detector component include, for example, semiconductor materials such as silicon or materials based on arsenide, phosphide, or nitride compound semiconductors.

[0029] According to at least one embodiment or configuration, the housing component comprises a cover element that is arranged on a side of the optical element facing away from the detector component and covers the detector component. The cover element may be designed to block external interference radiation.

[0030] According to at least one embodiment or configuration, the entire housing component can have an optical blocking function. For example, the housing component can include an optical blocking material, at least on its outer surfaces. It is possible that the housing component is a molded body comprising, for example, a resin or silicone. And the optical blocking material, for example, carbon particles, can be dispersed within the molded body.

[0031] According to at least one embodiment or configuration, the housing component has a rectangular shape in a top view of the detection unit.

[0032] According to at least one embodiment or configuration, the detection unit comprises at least one control element on which at least one of the laser radiation source and the detector component is arranged. During operation, the element arranged on the control element is controlled by the control element. The control element is, for example, an ASIC (Application-Specific Integrated Circuit).

[0033] The detection unit of the type described above can be used for a detection module, which can be composed of multiple such detection units. Therefore, all characteristics described in connection with the detection unit also apply to the detection module, and vice versa.

[0034] According to at least one embodiment of a detection module, it is designed to detect at least one property of an external object, as mentioned in connection with the detection unit, by

[0035] To determine self-mixing interference or interferometry. For example, the detection module comprises at least two detection units of the type mentioned above. Because the detection module includes more than one detection unit, it is suitable as a power readout module that can be used for multi-point measurement, for example, for eye-tracking applications, odometry, and distance and velocity mapping.

[0036] All detection units of the detection module can have the same design or architecture. Furthermore, the detection units can be arranged in a regular pattern. For example, the detection units can be arranged in a grid-like configuration of rows and columns.

[0037] According to at least one embodiment or configuration, the housing components of adjacent detection units are in contact. For example, the housing components of at least some of the detection units are formed in one piece.

[0038] According to at least one embodiment or configuration, the housing components of adjacent detection units form optical barriers between the detection units. Advantageously, crosstalk and optical coupling between the adjacent detection units can be reduced. As mentioned above, the housing components can comprise an optical blocking material. For example, the housing components can be made of a black material such as a resin or a silicone material with carbon particles.

[0039] According to at least one embodiment or configuration, the detection module comprises a carrier on which the laser radiation sources and detector components of the detection units are arranged. In particular, the carrier is composed of the carrier components of the detection units of the detection module. For example, the carrier components are formed in one piece. Suitable materials for the carrier components or the carrier are, for example, semiconductor materials such as silicon or ceramic materials such as aluminum nitride.

[0040] The detection unit and detection module are suitable for AR applications (AR: Augmented Reality), VR applications (VR: Virtual Reality), consumer, automotive and industrial applications.

[0041] The detection unit and the detection module are explained in more detail in connection with the figures described below. Fig. Figure 1A shows a schematic perspective view of an exemplary embodiment of a detection module and Fig. 1B a schematic cross-sectional view of a detection unit of the in Fig. 1A detection module shown along line D1. Fig. Figure 2A shows a schematic top view of another embodiment of a detection module and Fig. 2B a schematic cross-sectional view of a detection unit of the in Fig. 2A detection module shown along line AA'. Fig. Figures 3 to 6 show schematic cross-sectional views of further embodiments of detection modules, and Fig. Figure 7 shows a schematic cross-sectional view of another embodiment of a detection unit.

[0042] Identical, similar, or similarly functioning elements may be indicated by the same reference symbols in the figures. The figures are schematic representations and therefore not necessarily to scale. Rather, comparatively small elements, and especially layer thicknesses, may be exaggerated for clarity.

[0043] In connection with the Fig. 1A and Fig. Section 1B describes a first embodiment of an SMI detection module 100. Fig. Figure 1B shows a schematic cross-sectional view of a detection unit 10 of the detection module 100 along line D1.

[0044] The detection module 100 comprises a plurality of detection units 10, the number of which is not limited to the four shown. All detection units 10 have the same design. Furthermore, the detection units 10 are arranged in a regular, grid-like arrangement of rows and columns.

[0045] The detection units 10 each comprise a laser radiation source 1 and a detector component 2, which is arranged adjacent to the respective laser radiation source 1. The detector components 2 are separate components that are not integrated into the laser radiation sources 1. The respective separation of the detector components 2 from the laser radiation sources 1 has the advantage that the radiation or signals to be detected by the detector components 2 can be influenced without disturbing the integrity of the radiation or signals from the laser radiation sources 1.

[0046] Furthermore, each detection unit 10 comprises a housing component 3 that laterally surrounds the respective laser radiation source 1 and detector component 2. For example, "lateral" denotes lateral directions including a first lateral direction L1 and a second lateral direction L2, wherein the first lateral direction L1 and the second lateral direction L2 are oblique to each other, for example, perpendicular. The laser radiation source 1 and the detector component 2 are arranged in a cavity 4 of the respective laterally surrounding housing component 3. For example, the housing components 3 or cavities 4 have an at least approximately rectangular shape in the top view of the detection module 100, wherein the laser radiation source 1 and the detector component 2 can each be arranged along a diagonal D1 of the rectangular shape.However, it is possible that the laser radiation source 1 and the detector component 2 are arranged along any lateral direction including the first lateral direction L1 and the second lateral direction L2.

[0047] The housing components 3 can each comprise a plastic material such as a resin or a silicone. An optical blocking material, for example, carbon particles, can be dispersed in the plastic material, so that the housing components 3 have an optical blocking function and can serve as optical barriers. The housing components 3 can be manufactured by a molding process such as injection molding, so that the housing components 3 are molded bodies. For example, all housing components 3, or at least several of them, are formed in one piece.

[0048] Furthermore, each detection unit 10 comprises a carrier component 5 on which the respective laser radiation source 1 and detector component 2 are mounted and to which the respective housing component 3 is connected. The carrier components 5 each enclose a lower part of the cavity 4 of the respective housing component 3. A carrier 50 of the detection module 100 consists of the carrier components 5, which can be formed as a single piece. Suitable materials for the carrier components 5 or the carrier 50 are, for example, semiconductor materials such as silicon or ceramic materials such as aluminum nitride.

[0049] Furthermore, each detection unit 10 comprises an optical element 6 that covers the respective laser radiation source 1 and detector component 2. The optical elements 6 each have a flat, plate-like shape and can comprise or consist of a transparent material such as glass and / or plastic materials. In particular, the optical elements 6 are free of optical structures such as optical gratings and / or variations in refractive index. The optical elements 6 each enclose an upper part of the cavity 4 of the respective housing component 3.

[0050] The optical elements 6 are integrated into the top surfaces 3A of the respective housing components 3 such that the flat surfaces 6A of the optical elements 6 and the top surfaces 10A of the detection units 10 are each inclined to a principal extension plane of the respective detection unit 10 or detection module 100. The principal extension plane is, for example, a horizontal plane defined by the first lateral direction L1 and the second lateral direction L2. In particular, each optical element 6 is rotated out of a horizontal plane by a rotation, for example, about a diagonal axis D2 of the respective optical element 6, which may be inclined to the diagonal D1. Thus, the optical elements 6 are each tilted with respect to the principal extension plane of the respective detection unit 10 or detection module 100.For example, the optical elements 6 are each inclined with an acute angle of inclination α, which deviates from 45° and is preferably less than 45°.

[0051] The laser radiation sources 1 each comprise a laser diode 9, such as a VCSEL, which may be a single laser diode 9. The laser diode 9 includes an active zone 9C, which is arranged within an optical resonator 9A, 9B and emits electromagnetic laser radiation with a peak wavelength, for example, in the visible to infrared spectral range during operation. The detector components 2 can be photodiodes that are sensitive in a wavelength range of interference radiation detected during operation.

[0052] During operation, the laser radiation source 1 of each detection unit 10 can emit electromagnetic laser radiation S1 in a principal emission direction R, for example along a vertical direction V, which is perpendicular to the principal extension plane of the respective detection unit 10 or the detection module 100. In the first embodiment, the planar surfaces 6A of the optical elements 6 each have a surface normal N with a different orientation than the principal emission direction R of the laser radiation sources 1.

[0053] Part S1 t The laser radiation S1 is transmitted through the optical element 6 and emitted at the upper surface 10A, striking an external object O. A portion S2 of the laser radiation S1 striking the external object O tThe light is deflected to the detection unit 10, strikes the optical element 6, and is transmitted to the laser radiation source 1, where interference occurs in the optical resonator 9A, 9B of the laser radiation source 1. Interference radiation is generated by the interference of laser radiation S1 from the laser radiation source 1 and deflected laser radiation S2 from the external object O. The detector component 2 receives a portion of S1. r the interference radiation deflected by the optical element 6. The detection unit 10 or module 100 thus operates according to the principle of self-mixing interferometry or interference (SMI), whereby, for example, a changed amplitude, phase and / or frequency of the interference radiation compared to the original laser radiation S1 or to the deflected laser radiation S1 rcan be used to determine at least one property of the external object O. Due to a coherence length of the laser radiation sources 1, the working range of the SMI detection unit 10 or the SMI detection module 100 can be up to at least 5 meters.

[0054] The optical element 6 influences the part S1 directed towards the detector component 2. r the interference radiation is such that it is higher than without the optical element 6. Thus, the detection signal at the detector component 2 can be improved by the optical element 6.

[0055] By tilting the optical elements 6, the interference radiation projected by the respective optical elements 6 onto the detector components 2 can be optimized. Optimization of the projected radiation includes, for example, reducing the divergence β of the projected radiation. Furthermore, the height h, which denotes a vertical extent of the unit 10 or module 100 determined along the vertical direction V, and the base area, which denotes the size of a bottom surface 10B of each detection unit 10 or a bottom surface of the module 100 defined by a total area of ​​the bottom surfaces 10B, can be optimized. Finally, the pitch p, i.e., the lateral spacing of the detection units 10, can be reduced.

[0056] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0057] In connection with the Fig. 2A and Fig. Section 2B describes a second embodiment of an SMI detection module 100. Fig. Figure 2B shows a schematic cross-sectional view of a detection unit 10 of the detection module 100 along the line AA'.

[0058] In the second embodiment, the optical elements 6, each of which has a planar shape and can be designed in the same or a similar manner as described in connection with the first embodiment, are tilted by an angle α of 45°. The optical elements 6 serve as beam splitters, with half of the radiation incident on the optical elements 6 being deflected and the other half being transmitted, so that the interference radiation or the signal on the detector components 2 is maximized.

[0059] In the first embodiment, the laser radiation source 1 and the detector component 2 each have only a lateral distance from each other. In the second embodiment, the laser radiation source 1 and the detector component 2 each have a lateral distance a1, which is determined along a horizontal plane defined by the first and second lateral directions L1, L2, and a vertical distance a2, which is determined along the vertical direction V. For example, the laser radiation sources 1 are mounted on a surface of the respective support component 5, which can be horizontally oriented, while the detector components 2 are mounted on a side wall of the respective housing component 3, which can be vertically oriented.However, it is also possible for the detector components 2 to be mounted on the surface of the respective support component 5, while the laser radiation sources 1 are mounted on the side wall of the respective housing component 3. The surface of the support component 5 and the side wall can be perpendicular to each other. Although the assembly is more complex in the second embodiment than in the first, the detection module 100 offers a high signal-to-noise ratio (SNR), good immunity to external light sources, and a small footprint.

[0060] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0061] Combined with Fig. Section 3 describes a third embodiment of an SMI detection module 100. In this third embodiment, the optical elements 6 of the detection units 10 are waveguides, each comprising inclined planar surfaces 6A that serve to deflect, for example, refract, a portion of the interference radiation in the direction of the respective detection component 2. The inclined planar surfaces 6A are tilted with respect to the principal extension plane of the respective detection unit 10 or module 100. In particular, the waveguides can each have two inclined planar surfaces 6A, such that the waveguides have a prismatic cross-sectional shape that tapers in the principal emission direction R. Alternatively, instead of the planar surfaces 6A, the optical elements 6 can each have a curved surface, as described in conjunction with Fig. 5 is described.

[0062] The laser radiation source 1 and the detection component 2 of each detection unit 10 are arranged side by side within the respective waveguide. Advantageously, the height h of the detection units 10 can be minimized in the third embodiment. Furthermore, it is possible to implement the waveguides at the wafer level, which simplifies the fabrication process of the detection units 10 or the detection module 100.

[0063] The housing components 3 of the detection units 10 can each include a cover element 7, which is arranged on a side of the respective optical element 6 facing away from the detector component 2 and covers the respective detector component 2. The cover elements 7 are designed to block external interference radiation and thus improve the signal-to-noise ratio (SNR). The cover elements 7 can be formed integrally with the respective housing components 3. Therefore, the same materials can be used for the cover elements 7 and the housing components 3.

[0064] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0065] Combined with Fig. Section 4 describes a fourth embodiment of an SMI detection module 100. In this fourth embodiment, the detector components 2 are arranged on a control element 8, for example, integrated into it, wherein a single control element 8 can be provided for each detector component 2 or for several, even all, detector components 2. During operation, the detector components 2 are controlled by the control element(s) 8. The control element(s) 8 is / are, for example, an ASIC (Application-Specific Integrated Circuit). The laser radiation sources 1 can be controlled by the same or different control elements.

[0066] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0067] Combined with Fig. Section 5 describes a fifth embodiment of an SMI detection module 100. In this fifth embodiment, the optical elements 6 each have a curved surface 6A. The curved surface 6A can be approximated by a plurality of differently inclined regions with the same effect as described in connection with the first embodiment. Furthermore, the radiation projected onto the detector components 2 can be focused by the optical elements 6. The optical elements 6 each resemble a portion of a spherical or ellipsoidal surface.

[0068] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0069] Combined with Fig. Section 6 describes a sixth embodiment of an SMI detection module 100. In this sixth embodiment, the optical elements 6 are diffractive optical elements, which, for example, comprise a volume phase hologram. The optical elements 6 can have a planar or plate-like shape and be horizontally oriented without being tilted with respect to the principal extension plane of the detection units 10 or the detection module 100. This advantageously results in an even lower height of the unit or module compared to a unit or module with (one) inclined optical element(s).

[0070] Furthermore, the detection unit 10 or the detection module 100 can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0071] Combined with Fig.Section 7 describes a further embodiment of an SMI detection unit 10, wherein at least two of these units 10 can be combined to form a detection module. The detection unit 10 itself is, however, suitable for multi-point measurement.

[0072] The detection unit 10 comprises a laser radiation source 1, which includes an array of laser diodes 9, for example, an array of VCSELs. The laser radiation source 1 is located next to the detector component 2, which can be a single photodiode. Thus, one detector component 2 is sufficient to detect signals from multiple laser diodes 9. The laser diodes 9 can be operated sequentially. Time-division multiplexing can be used to drive each individual laser diode 9. The detection signal read out at the detector component 2 originates from a single laser diode 9 at each time point t0, t1, t2, etc., where t0 < t1 < t2. This unit 10 has a small footprint and reduced power consumption during operation.

[0073] Furthermore, the detection unit 10 or the detection module can have all the features, properties and advantages mentioned in connection with the further embodiments.

[0074] Alternatively or in addition to the features described in connection with the figures, the embodiments shown in the figures may include further features that are described in the general part of the description. Furthermore, features and embodiments of the figures may be combined with one another, even if such a combination is not expressly described.

[0075] The invention is not limited to the exemplary embodiments described therein. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the claims and every combination of features in the exemplary embodiments, even if that feature or combination is not expressly stated in the claims or exemplary embodiments. Reference symbol list 1 Laser radiation source 2 Detector component 3 Housing component 3A Top 4 Cavity 5 Carrier component 6 optical element 6A Surface 7 Cover element 8 Control element 9 Laser diode 9A, 9B optical resonator 9C active zone 10 detection units 10A top surface 10B underside surface 50 carriers 100 detection module α Angle of inclination β Divergence a1 lateral distance a2 vertical distance p Pitch t0, t1, t2 Time D1 Diagonal D2 diagonal axis L1 first lateral direction L2 second lateral direction N surface normal O external object R Main radiation direction S1 original laser radiation S1 t transmitted laser radiation S1 r deflected part of the interference radiation S2 transmitted, deflected laser radiation V vertical direction

Claims

[1] Detection unit (10) for determining at least one property of an external object (O), wherein the detection unit (10) is intended for self-mixing interferometry (SMI) and comprises: - a laser radiation source (1) designed to emit laser radiation (S1) and comprising an optical resonator (9A, 9B), - a detector component (2) which is arranged adjacent to the laser radiation source (1) and is intended for the detection of interference radiation, - a housing component (3) that laterally surrounds the laser radiation source (1) and the detector component (2), and - an optical element (6) covering the laser radiation source (1) and the detector component (2) and designed to provide a part (S1 r) of an interference radiation which arises in the optical resonator (9A, 9B) by interference of the laser radiation (S1) from the laser radiation source (1) and deflected laser radiation (S2) from the external object (O), to the detector component (2), wherein the optical element (6) deflects the part directed towards the detector component (2) (S1) r ) the interference radiation is influenced in such a way that it is higher than without the optical element (6). [2] Detection unit (10) according to the preceding claim, wherein the optical element (6) comprises at least one planar surface (6A) and the at least one planar surface (6A) has a surface normal (N) with an orientation other than a principal emission direction (R) of the laser radiation source (1). [3] Detection unit (10) according to one of the preceding claims, wherein the optical element (6) has a planar shape and is tilted with respect to a principal extension plane of the detection unit (10). [4] Detection unit (10) according to the preceding claim, wherein the optical element (6) is inclined at an acute angle of inclination (α) which deviates from 45°, and the laser radiation source (1) and the detector component (2) are mounted on a surface of a support component (5) to which the housing component (3) is connected. [5] Detection unit (10) according to claim 3, wherein the optical element (6) is a beam splitter and is inclined at an angle (α) of 45° and one of the laser radiation source (1) and the detector component (2) is mounted on a surface of a support component (5) which is connected to the housing component (3), and the other is mounted on a side wall of the housing component (3). [6] Detection unit (10) according to claim 1, wherein the optical element (6) has a curved surface (6A). [7] Detection unit (10) according to claim 1, 2 or the preceding claim, wherein the optical element (6) is a waveguide. [8] Detection unit (10) according to claim 1, wherein the optical element (6) is a diffractive optical element. [9] Detection unit (10) according to one of the preceding claims, wherein the laser radiation source (1) is a single laser diode (9). [10] Detection unit (10) according to one of claims 1 to 9, wherein the laser radiation source (1) comprises an arrangement of laser diodes (9) that can be operated sequentially. [11] Detection unit (10) according to one of the preceding claims, wherein the housing component (3) comprises a cover element (7) which is arranged on a side of the optical element (6) facing away from the detector component (2) and covers the detector component (2). [12] Detection unit (10) according to one of the preceding claims, comprising at least one control element (8) on which at least one of the laser radiation source (1) and the detector component (2) is arranged. [13] Detection unit (10) according to one of the preceding claims, wherein the detector component (2) is a photodiode. [14] Detection module (100) for determining at least one property of an external object (O), wherein the detection module comprises at least two detection units (10) according to one of the preceding claims, wherein the housing components (3) of adjacent detection units (10) touch and form optical barriers between the detection units (10). [15] Detection module (100) according to the preceding claim, comprising a carrier (50) on which the laser radiation sources (1) and detector components (2) of the detection units (10) are arranged.

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