Time-of-flight sensor and method for operating a time-of-flight sensor

Abstract

A time-of-flight sensor with the following features is provided: an emitter unit (1) with at least two VCSELs (4, 5) emitting electromagnetic laser radiation (6, 6') during operation, a receiver unit (2) configured for detection of electromagnetic laser radiation (6, 6') of the at least two VCSELs (4, 5), and an optical element (7) configured for redirecting electromagnetic laser radiation (6, 6') of the at least two VCSELs (4, 5) in different parts (8, 9) of a field of illumination (10). Further, a method for operating a time-of-flight sensor is provided.

Description

[0001] Description

[0002] TIME-OF- FLIGHT SENSOR AND METHOD FOR OPERATING A TIME-OF- FLIGHT SENSOR

[0003] A time-of- f light sensor and a method for operating a time-of- flight sensor are provided .

[0004] An improved time-of- f light sensor is to be provided . Particularly, a time-of- f light sensor having small dimensions and an improved crosstalk between an emitter unit and a receiver unit is to be provided .

[0005] Further, an improved method for operating a time-of- f light sensor is to be provided . Particularly, the method for operating the time-of- f light sensor should at least reduce the crosstalk between the emitter unit and the receiver unit .

[0006] These obj ects are achieved with a time-of- f light sensor having the features of claim 1 and the method for operating a time-of- f light sensor with the steps of claim 10 .

[0007] Improved developments and embodiments are given in the respective dependent claims .

[0008] According to an embodiment , the time-of- f light sensor comprises an emitter unit with at least two VCSELs ( short for : "vertical cavity surface emitting laser" ) emitting electromagnetic laser radiation during operation . Particularly, the emitter unit can comprise more than two VCSELs , for example three or more VCSELs . A VCSEL, particularly, comprises an epitaxial semiconductor layer sequence having an active zone configured for generation of electromagnetic radiation during operation . The active zone is , particularly, a laser active medium of the VCSEL . Particularly, the VCSEL comprises a resonator wherein the active laser medium, such as the active zone , is arranged . The resonator is , for example , formed by two oppositely arranged mirrors reflecting the electromagnetic radiation generated within the active zone . The mirrors are , for example , di f fractive Bragg reflectors applied to oppositely arranged main surfaces of the epitaxial semiconductor layer sequence . Particularly, the main extension plane of the mirrors , as well as of the active zone , run parallel to each other and further to a radiation exit surface of the VCSEL . Particularly, a radiation emission direction of the electromagnetic laser radiation emitted from the radiation exit surface of the VCSEL runs parallel to a growth direction of the epitaxial semiconductor layer sequence . For example , the VCSEL is a VCSEL chip comprising or consisting of a semiconductor material .

[0009] According to a further embodiment , the time-of- f light sensor comprises a receiver unit configured for detection of electromagnetic laser radiation of the at least two VCSELs . Particularly, the receiver unit is adapted to the wavelength and / or the intensity and / or emission spectrum and / or intensity and / or polari zation degree of the electromagnetic laser radiation of the VCSELs . I f the electromagnetic laser radiation emitted by the VCSELs di f fer from each other, the receiver unit is configured to detect di f ferent electromagnetic laser radiation . According to a further embodiment , the time-of- f light sensor comprises an optical element configured for redirecting electromagnetic laser radiation of the at least two VCSELs in di f ferent parts of a field of illumination . In other words , the optical element redirects electromagnetic laser radiation of one of the at least two VCSELs in one part of the field of illumination and the electromagnetic laser radiation of the other VCSEL of the at least two VCSELs in a further part of the field of illumination . I f the emitter unit comprises more than two VCSELs , the optical element redirects the electromagnetic laser radiation of each VCSEL in a di f ferent part of the field of illumination, in particular .

[0010] Particularly, the electromagnetic laser radiation emitted by one of the VCSELs is redirected in a di f ferent region than the electromagnetic laser radiation of the other VCSEL by the optical element . I f the unit comprises more than two VCSELs , the optical element redirects electromagnetic laser radiation of each VCSEL in a di f ferent region . Particularly, the electromagnetic laser radiation emitted by the at least two VCSELs does not overlap in the field of illumination .

[0011] For example , the optical element also widens the field of illumination of the VCSELs . For example , the optical element enlarges the field of illumination of the VCSELs from 15 ° to 25 ° to 70 ° to 90 ° , limits included .

[0012] According to an embodiment , the time-of- f light sensor comprises the emitter unit with the at least two VCSELs emitting the electromagnetic laser radiation during operation, the receiver unit configured for the detection of the electromagnetic laser radiation of the at least two VCSELs and the optical element redirecting the electromagnetic laser radiation of the at least two VCSELs in the di f ferent parts of the field of illumination .

[0013] It is an idea of the time-of- f light sensor to use at least two VCSELs for illuminating the field of illumination of the time-of- f light sensor to achieve high intensity illumination and high eye safety simultaneously . Particularly, the VCSELs of the emitter unit do not illuminate the same part of the field of illumination . The part of the field of illumination illuminated by one of the VCSELs of the emitter unit lies laterally displaced to the part of the field of illumination of another VCSEL of the emitter unit . Particularly, the parts of the field of illumination illuminated by the VCSELs do not overlap or overlap only in a small area . Therefore , the intensity of the electromagnetic laser radiation emitted by the VCSELs does not add up in the field of illumination . Since the VCSELs of the emitter unit illuminate separate zones of the retina of the eye of a human user, the eye is not harmed by a superposition of the electromagnetic laser radiation of the two VCSELs .

[0014] According to a further embodiment of the time-of- f light sensor, the optical element comprises at least two segments redirecting the electromagnetic laser radiation of the at least two VCSELs in di f ferent parts of the field of illumination . The at least two segments are , for example , arranged laterally to each other . Particularly, the at least two segments do not overlap with each other or overlap only in a small area . I f the time-of- f light sensor comprises an emitter unit with more than two VCSELs , the optical element particularly preferably comprises the same number of spatially separated segments , each segment redirecting the electromagnetic laser radiation of one VCSELs of the emitter unit in another part of the field of illumination .

[0015] Particularly preferably, the parts of the field of illumination illuminated by the di f ferent VCSELs do not overlap with each other or overlap only in a small area . Redirection of the electromagnetic laser radiation by the optical element takes place , for example , by optical refraction .

[0016] According to a further embodiment of the time-of- f light sensor, a first segment of the at least two segments of the optical element redirects electromagnetic radiation of a first VCSEL in a first part of the field of illumination and a second segment of the at least two segments of the optical element redirects electromagnetic radiation of a second VCSEL in a second part of the field of illumination .

[0017] According to a further embodiment of the time-of- f light sensor, the segments of the optical element are continuously connected to each other . For example , the segments of the optical elements are arranged directly adj acent to each other . For example , the optical element consists of the segments . I f the emitter unit comprises more than two VCSELs , the optical element comprises , preferably, the same number of segments as the emitter unit VCSELs . In other words , the optical element can be divided into the same number of segments as the number of VCSELs . Particularly, each segment directs electromagnetic laser radiation of the assigned VCSEL in an assigned part of the field of illumination . The parts of the field of illumination, for example , form the field of illumination . In other words , the parts of the field of illumination illuminated by the single VCSELs impose the field of illumination . According to a further embodiment of the time-of- f light sensor, the receiver unit comprises at least two segments and each segment of the receiver unit detects electromagnetic laser radiation of a part of a field of view of the receiver unit . For example , a first segment of the at least two segments of the receiver unit is configured to detect electromagnetic laser radiation of a first part of the field of view and a second segment of the at least two segments of the receiver unit is configured to detect electromagnetic laser radiation of a second part of the field of view . In other words , the field of view is subdivided into di f ferent parts being viewed by di f ferent segments of the receiver unit . For example , the parts of the field of view form the field of view . For example , the parts of the field of view, such as the first part and the second part , are arranged directly next to each other .

[0018] According to an embodiment of the time-of- f light sensor, the receiver unit comprises or consists of a photodiode , such as a single photon avalanche diode ( short : "SPAD" ) . Particularly, the receiver unit comprises or consists of a multitude or array of photodiodes , such as single photon avalanche diodes . Particularly, the single photon avalanche diode is a semiconductor chip, for example based on or consisting of a semiconductor material such as silicon .

[0019] The single photon avalanche diode particularly comprises a pn-j unction reverse biased at an operating voltage leading to a depleting zone . The operating voltage particularly exceeds the j unction breakdown voltage of the pn-j unction . Therefore , an electric field within the single photon avalanche diode is so high that a single charge carrier inj ected into the depletion zone triggers a self-sustaining charge carrier avalanche .

[0020] According to a further embodiment of the time-of-f light sensor, a distance between the emitter unit and the receiver unit does not exceed 3 millimeters. Particularly, the time- of-flight sensor is configured to be operated with no, only negligible or acceptable crosstalk between the emitter unit and the receiver unit. Therefore, it is possible to reduce a distance between the emitter unit and the receiver unit. This particularly leads to very small dimensions and / or a very small form factor of the time-of-f light sensor.

[0021] According to an embodiment of the time-of-f light sensor, the optical element is a lens, a diffractive optical element, a Fresnel lens or a multi-lens array. Particularly, the multilens array can comprise or consist of a plurality of micro lenses. The micro lenses of the multi-lens array can be equal or different from each other. For example, the optical element has focusing and / or diffusing properties.

[0022] According to an embodiment, a radiant energy and / or a radiant power of the time-of-f light sensor does not exceed a given threshold without the optical element. For example, the time- of-flight sensor still fulfills Class 1 eye safety limits according to 21CFR Part 1040 (up to date as of 1 / 26 / 2024) , the disclosure content of which is incorporated herein by reference, without the optical element. In other words, if the optical element is removed from the time-of-f light sensor, the time-of-f light sensor still fulfils Class 1 eye safety limits, for example according to 21CFR Part 1040 (up to date as of 1 / 26 / 2024) . Common time-of- f light sensors comprise , for example , an optical element which, besides guiding the light emitted from a light source in a desired way, protects the retina of the eye of a human user . In a common time-of- f light sensor, the optical element spreads the light of the light source , so that the light intensity impinging on the retina of the eye of the human user is below a given threshold, for example defined by Class 1 eye safety limits . I f the optical element is removed, for example due to damage to the time-of- f light sensor, the intensity of the light emitted by the common time-of- f light sensor lies above a given threshold, for example defined by Class 1 eye safety limits , and is possibly harmful for the retina . In order to ful fil eye-safety limits , a common time-of- f light sensor comprises a detection unit as a security element , such as an interlock multi-lens array, in order to be aware when the optical element is removed . Particularly, such a security element can be omitted in the present time-of- f light sensor .

[0023] The time-of- f light sensor disclosed herein can be operated with the method disclosed in the following . Therefore , features and embodiments disclosed in connection with the time-of- f light sensor can also be embodied within the method for operating a time-of- f light sensor and vice versa .

[0024] According to an embodiment of the method, a first VCSEL of the at least two VCSELs of the emitter unit is operated to emit electromagnetic laser radiation . For operating the VCSEL to emit electromagnetic laser radiation, an electrical current is applied to the active zone of the VCSEL and converted to electromagnetic laser radiation by the active zone . When the first VCSEL of the at least two VCSELs is operated to emit electromagnetic laser radiation, the first VCSEL is , in other words , switched on .

[0025] According to a further embodiment of the method, a second VCSEL of the at least two VCSELs is operated to emit electromagnetic laser radiation after operating the first VCSEL . The second VCSEL of the at least two VCSELs is operated to emit electromagnetic laser radiation in the same way as the first VCSEL . Particularly, the first VCSEL is switched of f when the second VCSEL is switched on and vice versa . In other words , only one VCSEL of the at least two VCSELs is switched on at the same time . This helps particularly preferably to reduce crosstalk between the emitter unit and the receiver unit . Further, a radiant energy and / or a radiant power of the emitter unit can be limited to a predetermined value , for example defined by the Class 1 eye safety limits , to achieve an eye safe operation of the time- of- flight sensor .

[0026] I f the time-of- f light sensor comprises more than two VCSELs , the VCSELs are switched on one after the other, particularly, while the other VCSELs are switched of f . In other words , only one VCSEL of the emitter unit is switched on at a time .

[0027] According to a further embodiment of the method, a first segment of the receiver unit detects electromagnetic laser radiation of a field of view emitted by the first VCSEL during a first time interval , and a second segment of the receiver unit detects electromagnetic laser radiation of a field of view emitted by the second VCSEL during a second time interval . Particularly, the first time interval and the second time interval are distinct from each other .

[0028] Particularly, during the first time interval the first VCSEL is switched on and the second VCSEL is switched of f , and during the second time interval the first VCSEL is switched of f and the second VCSEL is switched on . I f the emitter unit comprises more than two VCSELs , a respective number of time intervals is provided during the method for operating the time-of- f light sensor and one of the VCSELs is switched on during one of the time intervals wherein all of the other VCSELs are switched of f . All of the time intervals provided by the method are particularly distinct from each other and do not overlap .

[0029] Particularly, the time-of- f light sensor described herein can be part of a mobile phone . For example , the mobile phone further comprises a camera and the time-of- f light sensor is used for an autofocus function of the camera . For example , the autofocus function is a focus LDAF ( laser autofocus ) . With the present time-of- f light sensor, picture quality of a picture taken by the camera of the mobile phone can be improved advantageously .

[0030] Particularly, the time-of- f light sensor can be used in robots of consumer applications , for example autonomous robots such as vacuum cleaners , in industrial robots and / or drones and particularly, in the navigation of robots . Further, the time- of- flight sensor can be used in people counting, occupancy sensors , door automation, gesture sensors , a proximity sensors and collision avoidance .

[0031] Further advantageous embodiments and developments of the time-of- f light sensor and the method for operating a time-of- flight sensor result from the exemplary embodiments described below in connection with the Figures . Figure 1 shows a schematic view of a time-of- f light sensor according to an exemplary embodiment .

[0032] Figure 2 shows a schematic view of a stage of a time-of- flight sensor during a method for operating a time-of- f light sensor according to an exemplary embodiment .

[0033] Figure 3 shows a schematic view of a further stage of a time- of- flight sensor during the method for operating a time-of- flight sensor according to the exemplary embodiment of Figure 1 .

[0034] Figure 4 shows exemplarily a simulation of a plan view on an emitter unit of a time-of- f light sensor during operation .

[0035] Figure 5 shows exemplarily a further simulation of a plan view on an emitter unit of a time-of- f light sensor during operation .

[0036] Figure 6 shows exemplarily a simulation of cross talk of electromagnetic laser radiation emitted by an emitter unit and a receiver unit of a common time-of- f light sensor .

[0037] Figure 7 shows exemplarily a simulation of cross talk of electromagnetic laser radiation emitted by an emitter unit and a receiver unit of a time-of- f light sensor according to an exemplary embodiment .

[0038] Equal or similar elements as well as elements of equal function are designated with the same reference signs in the Figures . The Figures and the proportions of the elements shown in the Figures are not regarded as being shown to scale . Rather, single elements , in particular layers , can be shown exaggerated in magnitude for the sake of better presentation and / or better understanding .

[0039] The time-of- f light sensor according to the exemplary embodiment of Figure 1 comprises an emitter unit 1 and a receiver unit 2 . Particularly, the emitter unit 1 is attached to and the receiver unit 2 is integrated in a common sensor chip 3 and arranged at a distance D to each other, the so- called baseline .

[0040] The emitter unit 1 comprises at present a first VCSEL 4 and a second VCSEL 5 , both VCSELs 4 , 5 emitting electromagnetic laser radiation 6 , 6 ' during operation . Particularly, the two VCSELs 4 , 5 can be operated independently from each other . Particularly, the two VCSELs 4 , 5 of the emitter unit 1 can be switched on and of f independently from each other . When the first VCSEL 4 is switched on, the second VCSEL 5 can be switched of f and vice versa .

[0041] Further, the time-of- f light sensor comprises an optical element 7 configured for redirecting electromagnetic laser radiation 6 , 6 ' of the two VCSELs 4 , 5 in di f ferent parts 8 , 9 of a field of illumination 10 of the time-of- f light sensor . In the present exemplary embodiment , the optical element 10 has two segments 11 , 12 laterally arranged next to each other . A first segment 11 of the optical element 7 redirects the electromagnetic laser radiation 6 of the first VCSEL 4 in a first part 8 of the field of illumination 10 and a second segment 12 of the optical element 7 redirects the electromagnetic laser radiation 6 ' of the second VCSEL 5 in a second part 9 of the field of illumination 10 . In other words , the field of illumination 10 of the time-of- f light sensor is a segmented field of illumination . For example , the optical element 7 is a multi-lens array 13 having a plurality of micro lenses . For example , the first segment 11 of the multi-lens array 13 comprises a first number of micro lenses and the second segment 12 of the multi-lens array comprises a second number of micro lenses .

[0042] Further, the time-of- f light sensor of Figure 1 comprises a cover glass 14 covering the sensor chip 3 completely seen in plan view on the cover glass 14 .

[0043] The receiver unit 2 of the time-of- f light sensor comprises , for example one , two or a plurality of photodiodes as detecting elements . I f the receiver unit 2 of the time-of- flight sensor comprises a plurality of photodiodes as detecting elements , the photodiodes are , in most cases , arranged as an array . For example , the detecting element are single photon avalanche diodes .

[0044] The time-of- f light sensor comprises a further optical element 15 redirecting electromagnetic laser radiation 16 , 16 ' of a field of view 17 of the time-of- f light sensor to a focal plane of the receiver unit 2 . For example , the receiver unit 2 comprises a first segment 18 detecting electromagnetic laser radiation 16 of a first part 19 of the field of view 17 emitted by the first VCSEL 4 during a first time interval and a second segment 20 detecting electromagnetic laser radiation 16 ' of a second part 21 of the field of view 17 emitted by the second VCSEL 5 during a second time interval .

[0045] During operation, the electromagnetic laser radiation 6 , 6 ' emitted from the first VCSEL 4 and the second VCSEL 5 impinges on a radiation entrance surface 22 of the optical element and is redirected, for example by di f fraction, in the first part 8 of the field of illumination 10 and in the second part 9 of the field of illumination 10 . The electromagnetic laser radiation 6 , 6 ' leaves the optical element 7 from an emission surface 23 of the optical element 7 , passes the cover glass 14 , and runs through the field of illumination 10 of the time-of- f light sensor .

[0046] I f an obj ect (not shown) is arranged within the field of illumination 10 , the electromagnetic laser radiation 6 , 6 ' emitted by the both VCSELs 4 , 5 is at least partially reflected back to the time-of- f light sensor by the obj ect . The back reflected electromagnetic laser radiation 16 , 16 ' runs through the cover glass 14 and through the further optical element 15 . The further optical element 15 redirects the electromagnetic laser radiation 16 , 16 ' of the field of view 17 of the time-of- f light sensor, to a focal plane of a receiver unit 2 .

[0047] In connection with Figures 2 and 3 , a method for operating a time-of- f light sensor according to an exemplary embodiment is described . For example , the time-of- f light sensor of Figure 1 can be operated with the method according to the exemplary embodiment of Figures 2 and 3 .

[0048] During a first step of the method for operating a time-of- flight sensor, a first VCSEL 4 of an emitter unit 1 of the time-of- f light sensor is switched on during a first time interval and emits electromagnetic laser radiation 6 as shown in Figure 2 . The electromagnetic laser radiation 6 of the first VCSEL 4 runs through a first segment 11 of an optical element 7 of the time-of- f light sensor and is redirected in a first part 8 of a field of illumination 10 by the first segment 11 . Within the first time interval , a second VCSEL of the emitter unit of the time-of- f light sensor is switched of f ( Figure 2 ) . A second VCSEL 5 is switched of f during the first time interval .

[0049] During the first time interval , the electromagnetic laser 6 radiation of the first VCSEL 4 of the emitter unit 1 is detected by a first segment 18 of a receiver unit 2 of the time-of- f light sensor .

[0050] Then, during a second time interval immediately following the first time interval , the second VCSEL 5 of the emitter unit 1 is switched on and the first VCSEL 4 is switched of f simultaneously . Also , the electromagnetic laser radiation 6 ' of the second VCSEL 5 runs through the optical element 7 and is redirected by a second segment 12 of the optical element 7 in a second part 9 of the field of illumination 10 of the time-of- f light sensor . During the second time interval electromagnetic laser radiation 6 ' of the second VCSEL 5 is detected by a second segment 20 of the receiver unit 2 of the time-of- f light sensor ( Figure 3 ) .

[0051] Figures 4 and 5 show exemplarily simulations of the radiant intensity of radiation exit surfaces 24 of a first VCSEL 4 and a second VCSEL 5 of an emitter unit 1 of a time-of- f light sensor with a segmented field of illumination 10 .

[0052] Figure 4 shows exemplarily a simulation of the radiant intensity of the radiation exit surface 24 of the first VCSEL 4 when switched on and Figure 5 shows exemplarily a simulation of the radiant intensity of the radiation exit surface 24 of the second VCSEL 5 when switched on . For example, each VCSEL 4, 5 of the emitter unit 1 is operated at 50% of a duty cycle but at a double current, for example at 1 ampere compared to two VCSELs operated simultaneously of a common time-of-f light sensor.

[0053] Particularly, both VCSELs 4, 5 of the time-of-f light sensor are switched on with a current of 1 A in an alternating manner. In that case, the total input current is 1 A. A signal-to-noise ratio of the time-of-f light sensor, signal scales linearly with the optical power and time but noise only scales with a square-root of time. Therefore, the signal-to-noise ratio of a time-of-f light sensor with a segmented field of illumination 10 with two VCSELs 4, 5 illuminating subsequently different parts 8, 9 of the field of illumination 10 has, for example, a value of 2 / sqrt(2) , compared to the signal-to-noise ratio of a common time-of- flight sensor without a segmented field of illumination. Consequently, the signal-to-noise ratio of a time-of-f light sensor with two parts 8, 9 of the field of illumination 10 is improved by 41% compared to the signal-to-noise ratio of a common time-of-f light sensor without a segmented field of illumination operated with the same current.

[0054] Figures 6 and 7 show the simulated crosstalk (only rays which contribute to crosstalk are shown) of electromagnetic laser radiation 6 between an emitter unit 1 and a receiver unit 2 in combination with a cover glass 14. As an optical element 7 a multi-lens array 13 is used. The simulation is based on the assumption that the reflection coefficient of the electromagnetic laser radiation 6 at the interfaces between the cover glass 14 and the surrounding medium, such as air, is 5% . As shown in Figure 6 , a maj ority of the electromagnetic radiation 6 contributing to the crosstalk have triple reflections on the interfaces between the cover glass 14 and the surrounding medium, leading to a highly attenuated amplitude of the electromagnetic laser radiation 6 .

[0055] Figure 7 shows only electromagnetic laser radiation 6 contributing to the crosstalk, but outside of the field of illumination 10 of the optical element 7 . As these are outside the nominal field of view of the illumination, they have only minimal amplitude .

[0056] The features and exemplary embodiments described in connection with the Figures can be combined with each other according to further exemplary embodiments , even i f not all combinations are explicitly described . Furthermore , the exemplary embodiments described in connection with the Figures may alternatively or additionally have further features according to the description in the general part .

[0057] The present application claims priority of the German application DE 102024104985 . 5 , the disclosure content of which is incorporated herein by reference .

[0058] The invention is not limited to the description of the exemplary embodiments . Rather, the invention comprises each new feature as well as each combination of features , particularly each combination of features of the claims , even i f the feature or the combination of features itsel f is not explicitly given in the claims or the exemplary embodiments . References

[0059] 1 emitter unit

[0060] 2 receiver unit

[0061] 3 sensor chip 3

[0062] 4 first VCSEL

[0063] 5 second VCSEL

[0064] 6 , 6 ' electromagnetic laser radiation of a field of illumination

[0065] 7 optical element

[0066] 8 first part of the field of illumination

[0067] 9 second part of the field of illumination

[0068] 10 field of illumination

[0069] 11 first segment of the optical element

[0070] 12 second segment of the optical element

[0071] 13 multi-lens array

[0072] 14 cover glass

[0073] 15 further optical element

[0074] 16 , 16 ' electromagnetic laser radiation of a field of view

[0075] 17 field of view

[0076] 18 first segment of the receiver unit

[0077] 19 first part of the field of view

[0078] 20 second segment of the receiver unit

[0079] 21 second part of the field of view

[0080] 22 radiation entrance surface of the optical element

[0081] 23 emission surface of the optical element

[0082] 24 radiation exit surface of the VCSEL

[0083] D distance

Claims

Claims1. Time-of-f light sensor comprising:- an emitter unit (1) with at least two VCSELs (4, 5) emitting electromagnetic laser radiation (6, 6' ) during operation,- a receiver unit (2) configured for detection of electromagnetic laser radiation (6, 6' ) of the at least two VCSELs (4, 5) , and- an optical element (7) configured for redirecting electromagnetic laser radiation (6, 6' ) of the at least two VCSELs (4, 5) in different parts (8, 9) of a field of illumination (10) .

2. Time-of-f light sensor according to the previous claim, wherein the optical element (7) comprises at least two segments (11, 12) redirecting the electromagnetic laser radiation (6, 6' ) of the at least two VCSELs (4, 5) in different parts (8, 9) of the field of illumination (10) .

3. Time-of-f light sensor according to the previous claim, wherein- a first segment (11) of the at least two segments (11, 12) of the optical element (7) redirects electromagnetic laser radiation (6) of a first VCSEL (4) in a first part (8) of the field of illumination (10) , and- a second segment (12) of the at least two segments (11, 12) of the optical element (7) redirects electromagnetic laser radiation (6' ) of a second VCSEL (5) in a second part (9) of the field of illumination (10) .

4. Time-of-f light sensor according to the previous claim, wherein the at least two segments (11, 12) of the optical element (7) are continuously connected to each other.

5. Time-of-f light sensor according to any of the previous claims, wherein the receiver unit (2) comprises at least two segments (18, 20) and each segment (18, 20) of the receiver unit (2) detects electromagnetic laser radiation (16, 16' ) of a part (19, 21) of a field of view (17) .

6. Time-of-f light sensor according to the previous claim, wherein- a first segment (18) of the at least two segments (18, 20) of the receiver unit (2) is configured to detect electromagnetic laser radiation (16) of a first part (19) of the field of view (17) , and- a second segment (20) of the at least two segments (18, 20) of the receiver unit (2) is configured to detect electromagnetic laser radiation (16' ) of a second part (20) of the field of view (17) .

7. Time-of-f light sensor according to any of the previous claims, wherein the receiver unit (2) comprises at least one single photon avalanche diode.

8. Time-of-f light sensor according to any of the previous claims, wherein the optical element (7) is a lens, a diffractive optical element, a Fresnel lens or a multi-lens array (13) .

9. Time-of-f light sensor according to any of the previous claims, wherein a radiant energy and / or a radiant power of the time-of-f light sensor does not exceed a given threshold without the optical element ( 7 ) .

10. Method for operating a time-of-f light sensor according to any of the previous claims, the method comprises the steps:- operating a first VCSEL (4) of the at least two VCSELs (4, 5) of the emitter unit (1) to emit electromagnetic laser radiation (6) , and- operating a second VCSEL (5) of the at least two VCSELs (4, 5) to emit electromagnetic laser radiation (6' ) after operating the first VCSEL (4) .

11. Method according to the previous claim, wherein the first VCSEL (4) is switched off, when the second VCSEL (5) is switched on and vice versa.

12. Method according to any of claims 10 to 11, wherein- a first segment (18) of the receiver unit (2) detects electromagnetic laser radiation (16) of a field of view (17) emitted by the first VCSEL (4) during a first time interval, and- a second segment (20) of the receiver unit (2) detects electromagnetic laser radiation (16' ) of a field of view (17) emitted by the second VCSEL (5) during a second time interval .

13. Method according to the previous claim, wherein the first time interval and the second time interval are distinct from each other.14 . Mobile phone comprising a time-of- f light sensor according to any of claims 1 to 9 .15 . Mobile phone according to the previous claim, further comprising a camera, and the time-of- f light sensor is used for an autofocus function of the camera .

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