Optical device, in-vehicle system, and mobile device

Abstract

[Problem] To provide an optical device that is compact and capable of reducing the influence of reflected light. [Solution] An optical device (1) is provided with: a light-emitting unit (111) comprising a plurality of light-emitting elements (201); a light receiving unit (121) including a plurality of light receiving elements (301); an imaging optical system (130); a light splitting unit (155) including a reflector (151); and an acquisition unit (122, 123) that acquires distance information of the object on the basis of the time required from the emission of the light from the light emitting unit until the light receiving unit receives the light reflected by the object, the light from the light emitting unit being reflected by the reflector to pass through the imaging optical system to be reflected by the object, light reflected by the object passes through the imaging optical system to pass through the reflector to be received by the light receiving unit, a first light emitting element of the plurality of light emitting elements and a first light receiving element of the plurality of light receiving elements are in a conjugate relationship via the reflector, and the light splitting unit suppresses light from the first light emitting element from entering the first light receiving element.

Description

Technical Field

[0001] The invention relates to an optical device, a vehicle-mounted system and a movable device. Background Art

[0002] A time-of-flight (TOF) distance measurement method is known, which measures the distance to a subject by measuring the time difference from when light is irradiated onto the subject until reflected light from the subject is detected. Patent document 1 discloses a configuration including a light-emitting element and a light-receiving element arranged in two dimensions, wherein light is irradiated onto the subject through an imaging lens, reflected light from the subject is received, and three-dimensional distance information is acquired without a driving unit. This configuration requires that the viewing angle of the emitted light and the viewing angle of the received light are approximately equal. Therefore, in order to reduce the size of the distance measuring device, the light-emitting element array and the light-receiving element array may have approximately the same size and share an imaging lens.

[0003] Patent document 2 discloses a configuration for generating a third time series brightness signal by subtracting a second time series brightness signal depending on reflected light from outside the measuring object from a first time series brightness signal depending on reflected light from the measuring object, and generating a distance value to the measuring object based on the third time series brightness signal.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-60652

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2021-021597 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In the configuration disclosed in Patent Document 2, a plurality of reflecting mirrors are arranged in the optical path, making it difficult to reduce the influence of reflected light without increasing the size of the device.

[0010] Therefore, an object of the present invention is to provide an optical device which is compact and capable of reducing the influence of reflected light.

[0011] Solutions for solving problems

[0012] An optical device according to one aspect of the present invention includes: a light emitting unit including a plurality of light emitting elements arranged in a two-dimensional shape; a light receiving unit including a plurality of light receiving elements; an imaging optical system; a light splitting unit arranged between the imaging optical system and the light receiving unit, the light splitting unit including a reflector; and an acquisition unit configured to acquire distance information of an object based on a time required from the emission of light by the light emitting unit until the light receiving unit receives light reflected by the object, the light emitting elements in a first row and the light emitting elements in a second row of the plurality of light emitting elements emitting light at different times from each other in a time division manner, the optical axis direction of the imaging optical system is not parallel to a normal direction of the reflector, the light from the light emitting unit is reflected by the reflector to pass through the imaging optical system and thus reflected by the object, the light reflected by the object passes through the imaging optical system to be transmitted through the reflector and thus received by the light receiving unit, a first light emitting element among the plurality of light emitting elements and a first light receiving element among the plurality of light receiving elements are in a conjugate relationship via the reflector, and the light splitting unit is configured to suppress light from the first light emitting element from entering the first light receiving element.

[0013] Other objects and features of the present invention will be described in the following examples.

[0014] Effects of the Invention

[0015] The present invention can provide an optical device which is compact and can reduce the influence of reflected light. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a block diagram of a distance measuring device in various embodiments.

[0017] Figure 2 is a schematic diagram of a light projection unit in each embodiment.

[0018] Figure 3 is a schematic diagram of a measurement unit in each embodiment.

[0019] Figure 4 is a schematic diagram of a pixel in each embodiment.

[0020] Figure 5 is a schematic diagram of a TDC array unit in each embodiment.

[0021] Figure 6 is a schematic diagram of an oscillator in each embodiment.

[0022] Figure 7 1 is a table illustrating output signals of buffers of each stage and internal signals of the oscillator in each embodiment.

[0023] Figure 8 It is an explanatory diagram of changes in the cathode potential of the SPAD element, the pixel output signal, the synchronous clock, the synchronous clock counting circuit, the output of the oscillation start / stop signal generating circuit, the output of the oscillator, and the oscillation counting circuit in each embodiment.

[0024] Fig. 9 yes Figure 8 An enlarged view of the time period from time 803 to time 805.

[0025] Fig.10 is a block diagram of an oscillation adjustment voltage generating circuit in each embodiment.

[0026] Fig.11 is a configuration diagram of a main part of the distance measuring device in the first embodiment.

[0027] Fig.12 is a flowchart illustrating the distance measurement process in each embodiment.

[0028] Fig.13 is a configuration diagram of a main part of a distance measuring device in a second embodiment.

[0029] Fig.14 is a configuration diagram of a main part of a distance measuring device in a third embodiment.

[0030] Fig.15 is a configuration diagram of a main part of a distance measuring device in a fourth embodiment.

[0031] Fig.16 is a configuration diagram of a vehicle-mounted system having a distance measurement device according to any one of the above-described embodiments.

[0032] Fig.17 is a schematic diagram of a movable device having a distance measuring device according to any one of the above embodiments.

[0033] Fig.18 is a flowchart illustrating an example of the operation of an in-vehicle system having the distance measurement device according to any of the above-described embodiments. DETAILED DESCRIPTION

[0034] A detailed description of the embodiments according to the present invention will be described with reference to the accompanying drawings.

[0035] (First embodiment)

[0036] [Overall configuration of distance measuring equipment]

[0037] First, refer to Figure 1 , a schematic configuration of an optical device (distance measuring device) 1 of the first embodiment will be described. Figure 1 is a block diagram of the optical device 1. Figure 1 , a solid line illustrates communication of a signal, a dotted line illustrates light projected onto a subject (object), and a dotted line illustrates reflected light from the subject. The optical device 1 is an optical device (Light Detection and Ranging: LiDAR) that calculates the distance of an object based on the time between emission of light and arrival of light by a TOF method.

[0038] The optical device 1 includes a light projection unit 110, a measuring unit 120, an imaging lens (imaging optical system) 130, an overall control unit 140, and a light division unit 155 including a beam splitter 150. The light projection unit 110 includes a light source unit 113 having a light emitting element array (light emitting unit) 111 and a light emitting element driving unit 112, and a light source control unit 114. The light emitting element array 111 includes a plurality of light emitting elements 201 arranged in a two-dimensional shape (see Figure 2 ). The light emitting element array 111 is a sequential light emitting unit in which some light emitting elements (first row) and other light emitting elements (second row) among the plurality of light emitting elements 201 emit light at different times from each other in a time division manner.

[0039] The measuring unit 120 includes a light receiving element array (light receiving unit) 121, a TDC (time to digital converter) array unit 122, a signal processing unit 123, a measurement control unit 124, and a row selection circuit 125. The light receiving element array 121 includes a plurality of light receiving elements arranged in a two-dimensional shape. The beam splitter 150 includes a half mirror (reflector) 151 that transmits a portion of light and reflects another portion of light, and a reflection suppression structure 152. In the present embodiment, it is preferred to arrange a bandpass filter on the light receiving element array 121, which transmits light of a wavelength including the wavelength emitted by the light emitting element array 111 and reflects or absorbs light of other wavelengths.

[0040] Each light emitting element array 111 (each light emitting element 201 in a plurality of light emitting elements 201) in the light source unit 113 emits pulse light, and the pulse light is projected into space through the imaging lens 130. The pulse light emitted from each light emitting element 201 is projected into space at different viewing angles. The projected light is irradiated onto the subject (object), and a portion of the light reflected by the subject is received by the light receiving element array 121 via the imaging lens 130. The time from when the light emitting element array 111 emits light until the light receiving element array 121 receives the light is the time of flight TOF. The TDC array unit 122 is a measurement unit for measuring the time of flight TOF. However, it is difficult to remove noise components caused by noise light and dark counts such as ambient light in a single measurement, and the distance measurement error becomes larger due to the influence of noise in the measurement circuit. For this reason, the TDC array unit 122 repeatedly measures the time of flight TOF from the emission of light until the reception of light, and the signal processing unit 123 creates a histogram of the measurement results, removes the noise components, and averages the measurement results. The TDC array unit 122 and the signal processing unit 123 constitute an acquisition unit that acquires distance information of the subject based on the time required from the emission of light by the light emitting element array 111 until the light receiving element array 121 receives light reflected by the subject.

[0041] By substituting the time of flight TOF obtained in this manner into the following equation (1), the distance L to the subject can be determined with high accuracy. In equation (1), symbol c is the speed of light.

[0042] L=TOF × c / 2 … (1)

[0043] [Light projection unit]

[0044] Next, refer to Figure 2 , the light projection unit 110 will be described. Figure 2 A schematic diagram illustrating a light source unit 113 and a light source control unit 114 constituting the light projection unit 110. The light emitting element array 111 includes a plurality of light emitting elements 201. In the present embodiment, the light emitting element 201 is a VCSEL (vertical cavity surface emitting laser) arranged on a substrate in a two-dimensional shape. The light emitting element driving unit 112 includes a plurality of light emitting element row driving circuits 202 arranged in a one-dimensional shape. In the present embodiment, the light emitting element 201 is not limited to the VCSEL, but is preferably capable of being integrated in a one-dimensional or two-dimensional manner, such as an end-emitting laser or an LED (light emitting diode).

[0045] In the case of using an end-emitting laser instead of a VCSEL array as the light-emitting element 201, the light-emitting element array 111 is, for example, a laser bar formed by a one-dimensional array on a substrate, or a laser bar stack formed by a two-dimensional array of laser bars. In the case of using LEDs as the light-emitting element 201, the light-emitting element array 111 is LEDs arranged two-dimensionally on a substrate.

[0046] In the optical device 1 of the present embodiment, in order to suppress the influence of ambient light, the wavelength of the light emitted by the light emitting element 201 is preferably in the near-infrared band. However, the present embodiment is not limited to this. VCSEL is manufactured using semiconductor processes, using materials used in conventional end-emitting lasers and surface-emitting lasers. In the case where the VCSEL is configured to emit light in the near-infrared band, a GaAs-based semiconductor material can be used as the main material. In this case, a dielectric multilayer film constituting a DBR (distributed reflection type) reflector can be configured by alternately and periodically stacking two thin films (e.g., GaAs / AlGaAs) made of materials with different refractive indices, wherein the DBR reflector constitutes the VCSEL. The wavelength of the emitted light can be changed by adjusting the element combination or composition of the compound semiconductor.

[0047] The VCSELs constituting the VCSEL array are provided with electrodes for injecting current and holes into the active layer, and the electrodes are shared in the row direction and connected to the light emitting element row drive circuits 202 arranged in each row. By operating only the specific light emitting element row drive circuits 202 of the light emitting element drive unit 112, current is injected only into the VCSELs belonging to the specific row, and the light emitting elements 201 in the specific row can be made to emit light.

[0048] [Measurement unit]

[0049] Next, refer to Figure 3 , the measuring unit 120 will be described. Figure 3 Schematic diagram of the example measurement unit 120. The measurement unit 120 includes a light receiving element array 121, a TDC array unit 122, a signal processing unit 123, a measurement control unit 124, a row selection circuit 125, a row selection pulse line 303 and a pixel output line 304. The light receiving element array 121 includes a plurality of pixels (light receiving elements) arranged in a two-dimensional shape. The row selection circuit 125 only enables a specific row. The row selection pulse line 303 outputs the output signal of the row selection circuit 125 to the pixel 301. The pixel output line 304 outputs the output signal of the pixel 301 to the TDC array unit 122.

[0050] Now, refer to Figure 4 , the pixel 301 in this embodiment will be described. Figure 4is a schematic diagram of a pixel 301. The pixel 301 includes a SPAD element 401 as a light receiving element, a load transistor 402, an inverter 403, a pixel output circuit 404, a row selection pulse line 303, and a pixel output line 304. The SPAD element 401 includes a light receiving region and an avalanche region.

[0051] When light enters the SPAD element 401, photoelectric conversion occurs in the light receiving area, and electrons and holes are generated. Positively charged holes are discharged through the anode electrode Vbd. Negatively charged electrons as signal charges are transported to the avalanche region in the light receiving area through an electric field, which is set so that the potential decreases toward the avalanche region. The signal charge reaching the avalanche region causes avalanche breakdown due to the strong electric field in the avalanche region, and generates an avalanche current.

[0052] In the absence of an avalanche current flowing, the voltage of the anode electrode Vbd is set so that a reverse bias voltage above the breakdown voltage is applied to the avalanche region of the SPAD element 401. At this time, since no current flows in the load transistor 402, the cathode potential Vc is close to the power supply voltage Vdd, and the inverter output signal is "0". In the case where an avalanche current is generated in the SPAD element 401 due to the arrival of photons, the cathode potential Vc drops, and the output of the inverter 403 is reversed. In other words, the inverter output changes from "0" to "1". As the cathode potential Vc drops, the reverse bias applied to the SPAD element 401 becomes smaller, and when the reverse bias drops below the breakdown voltage, the generation of the avalanche current stops. Thereafter, the hole current flows from the power supply voltage Vdd to the cathode potential Vc via the load transistor 402, the cathode potential Vc rises, and the inverter output returns from "1" to "0" to enter the state before the photon arrives.

[0053] In the pixel 301 where the row selection pulse line 303 is turned on, the output signal of the inverter 403 is controlled to be output to the pixel output line 304. On the other hand, in the pixel 301 where the row selection pulse line 303 is turned off, the output signal of the inverter 403 is controlled to be disconnected from the pixel output line 304. Therefore, it is possible to detect only light incident on a specific row selected by the row selection circuit 125. Light detection at the pixel belonging to the row selected by the row selection circuit 125 is output to the TDC array unit 122 as a low-latency digital signal.

[0054] Next, refer to Figure 5 , the TDC array unit 122 will be described. Figure 5 A schematic diagram illustrating the TDC array unit 122. The TDC array unit 122 measures the time from when the light source unit 113 emits light until the pixel output signal changes from "0" to "1" as the ToF time.

[0055] In the TDC array unit 122, a TDC 501 is set for the number of pixels in the horizontal direction of the pixel array, and the TDC 501 measures the pixel output for one row at the same time. The TDC 501 has an oscillator 511, an oscillation counting circuit 521, and a synchronous clock counting circuit 531. The counting result of the synchronous clock counting circuit 531 is a high bit, the internal signal of the oscillator 511 is a low bit, and the counting result of the oscillation counting circuit 521 is a bit in between. In other words, the synchronous clock counting circuit 531 performs a rough measurement, the internal signal of the oscillator 511 performs a fine measurement, and the oscillation counting circuit 521 performs a measurement in between. Each circuit can also be configured to have a redundant bit.

[0056] Next, refer to Figure 6 , the oscillator 511 of the TDC 501 will be described. Figure 6 Schematic diagram illustrating an oscillator 511. The oscillator 511 includes an oscillation start / stop signal generating circuit 640, buffers 611 to 618, an oscillation switch 630, and a delay adjustment current source 620. The buffers 611 to 618 and the oscillation switch 630 are in a cyclic form in which eight stages are alternately connected.

[0057] Now, refer to Figure 7 , the output signals of the buffers 611 to 618 at each stage and the internal signal of the oscillator 511 will be described. Figure 7 This is a table illustrating the output signals of the buffers 611 to 618 at each stage and the internal signal of the oscillator 511 at the time of reset, and the output signals of the buffers 611 to 618 at each stage and the internal signal of the oscillator 511 after a certain time has passed since the oscillation switch 630 was turned on.

[0058] At the time of reset, the outputs of the buffers 611 to 617 are "0", and the output of the buffer 618 is "1". After a delay time t for one buffer stage has elapsed since the oscillation switch 630 is turned on buff After that, the outputs of the input and output aligned buffers 612 to 618 do not change, and only the output of the input and output unaligned buffer 611 changes from "0" to "1" (the signal advances one stage). buff Afterwards (at 2×t buff After that, the outputs of the buffers 611 and 613 to 618 whose input and output are aligned remain unchanged, and only the output of the buffer 612 whose input and output are not aligned changes from "0" to "1" (the signal advances one level). Therefore, the delay time t for each buffer level is buff , and sequentially change the output of a buffer whose input and output are not aligned. From the time the oscillation switch 630 is turned on, at 8×t buffAfter that, the outputs of all buffers change (the signal cycles once), and at 16×t buff After that, all buffers change again (the signal cycles twice) and return to the original state. buff Repeat the same operation time by time.

[0059] This is obtained by buff is the time measurement of the time resolution. The time resolution t buff The oscillation adjustment voltage generation circuit 541 described later adjusts the voltage to 1 / 2 of the synchronization clock. 7 The output of the buffer 618, which is the output of the oscillator 511, is input to the oscillation counting circuit 521. The oscillation counting circuit 521 counts the rising edges of the output of the oscillator 511 to obtain the value of 16×t buff The time resolution of the measurement time.

[0060] Figure 8 The cathode potential Vc of the SPAD element 401 , the pixel output signal, the synchronous clock, the synchronous clock count circuit 531 , the output of the oscillation start / stop signal generation circuit 640 , the output of the oscillator 511 , and the oscillation count circuit 521 are illustrated. Figure 8 The change of the timing from when the light emitting element 201 belonging to a specific row of the light emitting element array 111 emits light until the SPAD element 401 receives the reflected light and the TDC count operation is completed is illustrated.

[0061] The cathode potential Vc of the SPAD element 401 is an analog voltage, wherein the upper side of the paper shows a higher voltage. The output of the synchronous clock, the oscillation start / stop signal generating circuit 640, and the output of the oscillator 511 are digital signals, wherein the upper side of the paper shows on, and the lower side of the paper shows off. The synchronous clock counting circuit 531 and the oscillation counting circuit 521 are digital values ​​and are shown as decimal numbers.

[0062] Fig. 9 yes Figure 8 8 is an enlarged diagram from time 803 to time 805, which illustrates the output of the oscillation start / stop signal generating circuit 640, the output of the oscillator 511, the oscillation counting circuit 521, and the internal signal of the oscillator 511. The internal signal of the oscillator 511 is a digital value and is shown as a decimal number.

[0063] refer to Figure 8 and Fig. 9 , an operation of the TDC 501 measuring the time from the time 801 when the light emitting element 201 belonging to a specific row of the light emitting element array 111 emits light until the time 803 when the pixel receives a photon will be described.

[0064] The specific light emitting element row driving circuit 202 is driven so that the light emitting element 201 belonging to the specific row of the light emitting element array 111 emits light at a timing 801 that coincides with the rising edge of the synchronization clock supplied via the overall control unit 140. The synchronization clock counting circuit 531 starts counting the rising edges of the synchronization clock from the timing at which the light emitting element 201 emits light.

[0065] At time 803, the photons reflected from the subject are received by the pixel, the SPAD cathode potential Vc drops, and the pixel output signal changes from "0" to "1". When the pixel output signal changes to "1", the output of the oscillation start / stop signal generating circuit 640 changes from "0" to "1", and the oscillation switch 630 is turned on. When the oscillation switch 630 is turned on, the oscillation operation starts, and as shown in FIG. Fig. 9 As illustrated in , the signal cycle inside the oscillator begins. Every two signal cycles inside the oscillator, a rising edge appears at the oscillator output, and the number of rising edges is measured by the oscillation counting circuit 521. At time 803, the synchronous clock counting circuit 531 stops counting and holds the value.

[0066] The timing of the first rise of the synchronous clock after the oscillator 511 is turned on is at time 805. When the synchronous clock rises, the output of the oscillation start / stop signal generating circuit 640 becomes "0", and the oscillation switch 630 is turned off. At the timing when the oscillation switch 630 becomes "0", the oscillation is terminated, and the internal signal of the oscillation circuit remains as it is. Since the oscillation stops, the counting of the oscillation counting circuit 521 also stops.

[0067] As a result, the count result D of the synchronous clock counting circuit 531 is Gclk So 2 7 ×t buff The value obtained by counting the time from time 801 to time 802. The counting result D of the oscillation counting circuit 521 ROclk So 2 4 ×t buff The value obtained by counting the time from time 803 to time 804. The internal signal D of the oscillator 511 ROin The time t buff A value obtained by counting the time from time 804 until time 805. After these signals are processed as follows, they are output to the signal processing unit 123 to complete one TDC operation.

[0068] The counting result D of the oscillation counting circuit 521 ROclk and the internal signal D of the oscillator 511 ROin The sum is obtained using the following formula (2).

[0069] D RO =2 4 ×D ROclk +D ROin …(2)

[0070] D RO is t buff The time counted from time 1804 until time 1805, and the time from time 802 until time 805 is the period of the synchronous clock, which is equal to 2 7 ×t buff Therefore, as shown in the following equation (3), D is subtracted from the synchronous clock RO And with D Gclk Add them together to get the value D ToF , the value D ToF is t buff The flight time of light (the time from time 801 to time 803) is counted.

[0071] D ToF =2 7 ×D Gclk +(2 7 -D RO )

[0072] =2 7 ×D Gclk +(2 7 -2 4 ×D ROclk -D ROin )...(3)

[0073] Since the delay time t for a buffer stage buff Since the voltage varies depending on process factors such as transistor manufacturing errors, fluctuations in voltage applied to the TDC circuit, and temperature, an oscillation adjustment voltage generating circuit 541 is arranged at each TDC.

[0074] Fig.10 1 is a block diagram of an oscillation adjustment voltage generating circuit 541. The oscillation adjustment voltage generating circuit 541 includes a dummy oscillator 1001, a 1 / 2 3 Frequency divider 1002 and phase comparator 1003. Dummy oscillator 1001 is the same oscillator as oscillator 511 in TDC 501.

[0075] The output of the dummy oscillator 1001 is input to the 1 / 2 3 Divider 1002.1 / 2 3 The frequency divider 1002 outputs a clock frequency that is half the input clock frequency. 3 The clock signal circuit. Synchronous clock and 1 / 2 3The output of the frequency divider 1002 is input to the phase comparator 1003. The phase comparator 1003 compares the frequency of the synchronous clock with 1 / 2 3 The frequency of the output signal of the frequency divider 1002 is compared. When the frequency of the synchronous clock is high, the output voltage increases, and when the frequency of the synchronous clock is low, the output voltage decreases. The output voltage of the phase comparator is input to the delay adjustment current source 620 of the oscillator to adjust the oscillator frequency to 2 times the synchronous clock frequency. 3 times the voltage.

[0076] Therefore, the oscillation frequency is determined based on the synchronization clock frequency. Therefore, by generating a synchronization clock based on an external IC that can output a constant frequency regardless of process / voltage / temperature changes, frequency changes due to process / voltage / temperature changes can be suppressed. For example, by inputting a 160MHz clock to the synchronization clock frequency, the oscillation frequency becomes 1.28GHz, which is 8 times the synchronization clock frequency. The delay time t for one buffer stage as the time resolution buff It is 48.8ps.

[0077] [Beam splitter suppresses reflected light]

[0078] Next, refer to Fig.11 (A) to (C) describe the suppression of reflected light by the beam splitter 150 of this embodiment. Fig.11 (A) to (C) are configuration diagrams of a main portion of the optical element 1 , and illustrate cross sections of the beam splitter 150 , the light emitting element array 111 , the light receiving element array 121 , and the imaging lens 130 .

[0079] exist Fig.11 In (A), the light emitting element array 111 and the light receiving element array 121 are conjugated via the half mirror 151 of the beam splitter 150, and each light emitting element and each light receiving element are also conjugated. Fig.11 In (A), both the light emitting element array 111 and the light receiving element array 121 are illustrated as an example of an 8-row configuration, but the number of rows is not limited to this. In this embodiment, the light emitting elements and the light receiving elements are configured to have a one-to-one conjugate relationship, but are not limited to this, and the number of light receiving elements may be n×n times the number of light emitting elements, and one light emitting element and n×n light receiving elements may be configured to have a conjugate relationship. Fig.11 In (A), the row numbers of the light emitting element array 111 are assigned in ascending order from the smaller Yv side to the larger Yv side. Fig.11 In (A), the row numbers of the light receiving element array 121 are assigned in ascending order from the smaller Y side to the larger Y side, and the light emitting element array 111 and the light receiving element array 121 having the same row number are in a conjugate relationship.

[0080] Fig.11 (B) illustrates the optical path of light emitted from the light emitting element in row number 1 of the light emitting element array 111. The light 1110 emitted from the light emitting element array 111 is split into the light 1111 which is reflected by the half mirror 151 and irradiated onto the subject, and the light 1112 which passes through the half mirror 151 and travels toward the reflection suppression structure 152.

[0081] Fig.11 (C) illustrates reflected light 1113 from the subject and reflected light 1114 from the reflection suppressing structure 152. The reflected light 1113 from the subject is incident on the light receiving element in a conjugate relationship with the light emitting element that emits the light.

[0082] The surface of the reflection suppression structure 152 irradiated by the light 1112 uses a surface structure that transmits or absorbs or both transmits and absorbs, so that the reflectivity of the wavelength of light emitted from the light emitting element array 111 is low. The surface structure can be a stacked structure of dielectric materials with different refractive indices, or an anti-reflection structure composed of multiple structures finer than the wavelength. The surface structure can also be an absorbing material such as metal. The shape of the reflection suppression structure 152 is a periodic structure (for example, a rectangular shape) that is twice the spacing between the light emitting element points in the row direction of the light emitting element, and is the same shape in the paper depth direction of the cross-sectional view. The reflection suppression structure 152 can also be a cylindrical lens shape with a period that is twice the spacing of the light emitting element. With the reflection suppression structure 152 having such a shape, the reflected light 1114 at the reflection suppression structure 152 is offset by one row and enters the half-reflecting mirror 151, and enters the light receiving element in the row that is not conjugated with the light emitting element that emits the light.

[0083] As in the distance measurement process described below, in the light receiving element, the pixel output of the light receiving element in the row conjugate with the row of the light emitting element emitting light is output to the TDC. Therefore, the TDC detects the time from the light emission moment until the light is incident on the light receiving element in the row conjugate with the row of the light emitting element, and does not respond to the light incident on other rows. Therefore, it is possible to suppress the false detection caused by the light 1112 incident on the light receiving element that is not conjugate with the light emitting element emitting light. The above description for the first row is also applicable to the other rows.

[0084] [Distance measurement processing]

[0085] Next, refer to Fig.12 , a distance measurement process for acquiring 3D distance information using the optical device 1 will be described. Fig.12 is a flowchart illustrating a distance measurement process.

[0086] First, in step S1201, the overall control unit 140 (measurement control unit 124) resets the row counter j and sets it to 1. Subsequently, in step S1202, the measurement control unit 124 selects the row corresponding to the row counter using the row selection circuit 125, and sets the pixel signal of the corresponding row to be output to the TDC array unit 122 via the pixel output line 304. Subsequently, in step S1203, the measurement control unit 124 resets the same number of histogram circuits as the TDC 501 configured in the signal processing unit 123, and resets the measurement counter i.

[0087] Subsequently, in step S1204, the overall control unit 140 (light source control unit 114) operates the light emitting element row driving circuit 202 of the row corresponding to the row counter j, and causes the light emitting element 201 belonging to the corresponding row to emit short pulse light. Subsequently, in step S1205, the light source control unit 114 determines whether the time elapsed from the light emission is less than or equal to the time Tmax corresponding to the longest measurement distance. In the case where it is determined that the time elapsed from the light emission is greater than the time Tmax, the process proceeds to step S1209. On the other hand, in the case where it is determined that the time elapsed from the light emission is less than or equal to the time Tmax, the process proceeds to step S1206. In step S1206, the light source control unit 114 determines whether the pixel output is "1". In the case where it is determined that the pixel output is "1", the process proceeds to step S1207. On the other hand, in the case where it is determined that the pixel output is not "1", the process returns to step S1205. In other words, the process waits until the time elapsed from the light emission is greater than the time Tmax or the pixel output is "1".

[0088] During the standby state, light reflected back from the subject enters the light receiving element conjugate with the light emitting element that emits the light. When the pixel output signal becomes "1" due to the reception of light, in step S1207, the overall control unit 140 measures the time elapsed from the light emission using the TDC 501. Subsequently, in step S1208, the overall control unit 140 stores (adds) the TDC result to the histogram and returns to the standby state again.

[0089] In the case where the time elapsed from the light emission exceeds the time Tmax, in step S1209, the light source control unit 114 increases the emission counter i by 1. Subsequently, in step S1210, the light source control unit 114 determines whether the emission counter i is greater than a preset number of emission counts N total When it is determined that the transmission counter i is less than the transmission count N total In the case of, the process proceeds to step S1204. On the other hand, if it is determined that the transmission counter i is greater than the transmission count N totalIn this case, the processing proceeds to step S1211.

[0090] In step S1211, the measurement control unit 124 performs histogram signal processing to calculate distance measurement results such as measured distance, signal strength, and ambient light intensity based on the histogram of the TDC result. Subsequently, in step S1212, the measurement control unit 124 outputs the distance measurement result (row signal output) calculated in step S1211 from the measurement unit 120. Steps S1202 to S1212 complete the distance measurement processing for one row and output the distance measurement result. Subsequently, in step S1213, the measurement control unit 124 increases the row counter j by 1.

[0091] Then, in step S1214, the measurement control unit 124 determines whether the row counter j is greater than the number of rows N. row (exist Fig.11 In the case of N row = 8). When it is determined that the measurement counter j is less than or equal to the set number of times N row In the case where the measurement counter j is greater than the set number of times N, the process proceeds to step S1202, and the overall control unit 140 performs distance measurement processing for the next row. row In the case of , since the distance measurement process for all rows has been completed, the distance measurement process ends. Through the above distance measurement process, a distance measurement result in the form of a two-dimensional array such as image information can be obtained.

[0092] In this embodiment, the light emitting element array 111 is made to emit light at different times for each row, and only the light emitting elements of the rows emitting light in the light emitting element array 111 and the light receiving elements conjugated via the half mirror 151 are made effective. In the beam splitter 150, the reflection suppression structure 152 is provided on the surface opposite to the light emitting element array 111 across the half mirror 151. This enables distance measurement processing that suppresses erroneous detection (erroneous distance measurement) caused by reflected light.

[0093] (Second embodiment)

[0094] Next, refer to Fig.13 (A) to (C) of the present invention will be described. Fig.13 (A) to (C) illustrate the configuration diagram of the main parts of the optical device (distance measuring device) in this embodiment. The difference between this embodiment and the first embodiment is that a reflection suppression structure 1301 is provided instead of the reflection suppression structure 152. The other configurations are the same as those in the first embodiment, so their description is omitted.

[0095] Fig.13(A) illustrates cross sections of the beam splitter 150 , the light emitting element array 111 , the light receiving element array 121 , and the imaging lens 130 . Fig.13 (B) illustrates the optical path of light emitted by the light emitting element of row number 1 of the light emitting element array 111 . Fig.13 (C) illustrates the reflected light 1113 from the subject and the reflected light 1302 from the reflection suppression structure 1301 .

[0096] The reflection suppression structure 1301 in this embodiment is not a periodic structure with a period twice that of the light emitting element 201, but a diffuse reflection surface with suppressed reflectivity. The diffuse reflection of the reflection suppression structure 1301 can suppress the light reflected by the beam splitter 150 from entering the light receiving element conjugate with the light emitting element, thereby suppressing erroneous distance measurement.

[0097] (Third Embodiment)

[0098] Next, refer to Fig.14 (A) to (C) of the present invention will be described. Fig.14 (A) to (C) illustrate configuration diagrams of the main parts of the optical device (distance measuring device) in this embodiment. The difference between this embodiment and the first and second embodiments is that the polarization information of light is used to suppress the light from being incident on the light receiving element conjugate with the light emitting element. In other words, in this embodiment, a polarizer (first polarizer) 1401 is configured between the light emitting element array 111 and the beam splitter 150, and a polarizer (second polarizer) 1402 is configured between the beam splitter 150 and the light receiving element array 121. Since the other configurations are the same as in the first and second embodiments, their descriptions are omitted.

[0099] Fig.14 (A) illustrates a cross section of the beam splitter 150, the light emitting element array 111, the light receiving element array 121, the imaging lens 130, and the polarizers 1401 and 1402. For example, the polarizer 1401 and the polarizer 1402 constitute polarizers having mutually orthogonal orientations. Fig.14 (B) illustrates the optical path of light emitted by the light emitting element of row number 1 of the light emitting element array 111. The light passing through the polarizer 1401 becomes light having linear polarization in the x direction (or y direction). Fig.14(C) illustrates an optical path 1403 of reflected light 1113 from the subject and reflected light from the surface 1410 of the beam splitter 150. The reflected light from the subject has a smaller polarization. On the other hand, due to mirror reflection, the reflection at the surface 1410 of the beam splitter 150 is light with linear polarization in the x direction (or y direction). A portion of the reflected light from the subject passes through the polarizer 1402. On the other hand, the reflected light from the surface 1410 of the beam splitter 150 does not pass through the polarizer 1402 and does not enter the light receiving element array 121.

[0100] In this embodiment, polarizer 1401 is arranged between light emitting element array 111 and beam splitter 150, and polarizer 1402 is arranged between beam splitter 150 and light receiving element array 121. This can suppress light reflected by beam splitter 150 from entering light receiving element array 121, thereby suppressing erroneous distance measurement.

[0101] (Fourth embodiment)

[0102] Next, refer to Fig.15 (A) to (C) of the present invention will be described. Fig.15 (A) to (C) illustrate configuration diagrams of the main parts of the optical device (distance measuring device) in this embodiment. The difference between this embodiment and the first to third embodiments is that the polarization information of light and the reflection suppression structure 1502 of the beam splitter 150 are used to suppress the light from being incident on the light receiving element conjugate with the light emitting element. In other words, in this embodiment, a polarizer 1501 is configured between the light emitting element array 111 and the beam splitter 150, and a reflection suppression structure 1502 is formed on the beam splitter 150. The other configurations are the same as in the first to third embodiments, and therefore their description is omitted.

[0103] Fig.15 (A) illustrates a cross section of the beam splitter 150, the light emitting element array 111, the light receiving element array 121, the imaging lens 130, the polarizer 1501, and the reflection suppressing structure 1502. The shape of the reflection suppressing structure 1502 is a structure in which a plane parallel to the YZ plane and a plane inclined relative to the YZ plane are repeated at the same interval as the row direction interval of the light emitting elements. Fig.15 (B) illustrates the optical path of light emitted by the light emitting element of row number 1 of the light emitting element array 111 . Fig.15 (C) illustrates reflected light 1113 from the subject.

[0104] The polarizer 1501 is configured so that the light passing through the polarizer 1501 is p-polarized light with respect to the plane that is inclined relative to the YZ plane and constitutes the reflection suppression structure 1502. The plane that is inclined relative to the YZ plane and constitutes the reflection suppression structure 1502 is set so that the angle between the normal line of the plane and the light 1112 after passing through the half mirror is the Brewster angle. This configuration makes it possible to suppress reflection at the reflection suppression structure 1502.

[0105] [In-vehicle system]

[0106] Fig.16 1 is a configuration diagram of an optical device 1 according to each embodiment and an in-vehicle system (driving support device) 1000 including the optical device 1. The in-vehicle system 1000 is a system that is held by a movable unit (movable device) such as a car (vehicle) and is configured to support driving (operation) of the vehicle based on distance information to objects such as obstacles and pedestrians around the vehicle acquired by the optical device 1. Fig.17 1 is a schematic diagram of a vehicle 500 as a movable device including an in-vehicle system 1000. Fig.17 , the distance measurement range (detection range) of the optical device 1 is set to the front of the vehicle 500 , but the distance measurement range may be set to the rear or side of the vehicle 500 .

[0107] like Fig.16 As illustrated in FIG. 1 , the vehicle-mounted system 1000 includes an optical device 1, a vehicle information acquisition device 200, a control device (controller or electronic control unit (ECU)) 300, and a warning device (warning unit) 400. In the vehicle-mounted system 1000, the overall control unit 140 in the optical device 1 is used as a distance acquisition unit and a collision judgment unit. However, if necessary, the vehicle-mounted system 1000 may include a distance acquisition unit and a collision judgment unit separated from the overall control unit 140, or the distance acquisition unit and the collision judgment unit may each be set outside the optical device 1 (for example, inside the vehicle 500). Alternatively, the control device 300 may be used as the overall control unit 140.

[0108] Fig.18 2 is a flowchart illustrating an example operation of the in-vehicle system 1000 according to the present embodiment. The operation of the in-vehicle system 1000 will now be described with reference to this flowchart.

[0109] First, in step S1, the light source unit 113 in the optical device 1 illuminates the object around the vehicle, and the light receiving element array 121 receives the reflected light from the object, and the overall control unit 140 acquires the distance information of the object based on the signal output by the light receiver 121. In step S2, the vehicle information acquisition device 200 acquires vehicle information including vehicle speed, yaw rate, steering angle, etc. In step S3, the overall control unit 140 uses the distance information acquired in step S1 and the vehicle information acquired in step S2 to determine whether the distance to the object is within the previously set distance range.

[0110] This configuration can determine whether there is an object within the set distance around the vehicle and the possibility of a collision between the vehicle and the object. Steps S1 and S2 can be performed in the reverse order of the above, or can be processed in parallel with each other. The overall control unit 140 determines that there is a possibility of a collision when there is an object within the set distance (step S4), and determines that there is no possibility of a collision when there is no object within the set distance (step S5).

[0111] Next, when the overall control unit 140 determines that there is a possibility of a collision, the overall control unit 140 notifies (transmits) the judgment result to the control device 300 and the warning device 400. At this time, the control device 300 controls the vehicle based on the judgment result of the overall control unit 140 (step S6), and the warning device 400 issues a warning to the user (driver, passenger) of the vehicle based on the judgment result of the overall control unit 140 (step S7). The notification of the judgment result may be sent to at least one of the control device 300 and the warning device 400.

[0112] The control device 300 can control the movement of the vehicle by outputting a control signal to a driving unit (engine, motor, etc.) of the vehicle. For example, the control device 300 performs control such as applying brakes in the vehicle, releasing the accelerator, turning the steering wheel, and generating a control signal for generating a braking force in each wheel to suppress the output of the engine or motor. In addition, the warning device 400 issues a warning to the user by, for example, emitting a warning sound, displaying a warning message on a screen of a car navigation system, etc., and applying vibration to a seat belt or a steering wheel.

[0113] As described above, the vehicle-mounted system 1000 according to the present embodiment can detect and measure the distance to the object through the above-mentioned processing, and can avoid the collision between the vehicle and the object. In particular, applying the optical device 1 according to each embodiment to the vehicle-mounted system 1000 can achieve high distance measurement accuracy, and detect the object with high accuracy and determine the collision.

[0114] In the present embodiment, the vehicle-mounted system 1000 is applied to driving support (collision damage mitigation), but the present embodiment is not limited to this example, and the vehicle-mounted system 1000 may be applied to cruise control (including an adaptive cruise control function) and automatic driving. The vehicle-mounted system 1000 is not limited to vehicles such as automobiles, but may be applied to movable units such as ships, aircraft, and industrial robots. The vehicle-mounted system 1000 is not limited to movable units, but is applicable to various devices using object recognition such as intelligent transportation systems (ITS) and surveillance systems.

[0115] The in-vehicle system 1000 and the vehicle (movable device) 500 may include a notification device (notification unit) for notifying the manufacturer (producer) of the in-vehicle system or the dealer (seller) of the movable device that the vehicle 500 has collided with an obstacle (if any). For example, the notification device may be a device for transmitting information (collision information) related to the collision between the vehicle 500 and the obstacle to a preset external notification destination via e-mail or the like.

[0116] The configuration of the notification device automatically notifying collision information in this manner can take measures such as inspection and repair immediately after the collision occurs. The notification destination of the collision information can be an insurance company, a medical institution, a police station, or any other party arbitrarily set by the user. The notification device can be configured to notify the notification destination not only of the collision information, but also of the fault information related to each part and the consumption information related to the consumables. The presence or absence of a collision can be detected using the distance information obtained based on the output from the light receiver 121, or can be detected by other detectors (sensors).

[0117] Embodiments may provide a compact optical device, a vehicle-mounted system, and a movable device capable of reducing the influence of reflected light.

[0118] Disclosure of the embodiments includes the following configurations.

[0119] (Configuration 1)

[0120] An optical device comprising:

[0121] a light emitting unit including a plurality of light emitting elements arranged in a two-dimensional shape;

[0122] a light receiving unit including a plurality of light receiving elements;

[0123] Imaging optical system;

[0124] a light splitting unit disposed between the imaging optical system and the light receiving unit, the light splitting unit including a reflector; and

[0125] an acquisition unit configured to acquire distance information of the object based on a time required from when the light emitting unit emits light until when the light receiving unit receives light reflected by the object,

[0126] wherein the light emitting elements in the first row and the light emitting elements in the second row of the plurality of light emitting elements emit light at different times from each other in a time division manner,

[0127] Wherein, the optical axis direction of the imaging optical system is not parallel to the normal direction of the reflector,

[0128] wherein the light from the light emitting unit is reflected by the reflector to pass through the imaging optical system and then be reflected by the object,

[0129] wherein the light reflected by the object passes through the imaging optical system to be transmitted through the reflector and thus received by the light receiving unit,

[0130] wherein a first light emitting element among the plurality of light emitting elements and a first light receiving element among the plurality of light receiving elements are in a conjugate relationship via the reflector, and

[0131] The light splitting unit is configured to suppress light from the first light emitting element from entering the first light receiving element.

[0132] (Configuration 2)

[0133] The optical device according to configuration 1,

[0134] Wherein, the light splitting unit includes a beam splitter, and the beam splitter includes the reflector,

[0135] wherein the beam splitter comprises a reflection suppression structure on a surface opposite to a surface facing the light emitting unit, and

[0136] The reflection suppressing structure suppresses light emitted from the first light emitting element, transmitted through the reflector, and reflected by the reflection suppressing structure from entering the first light receiving element.

[0137] (Configuration 3)

[0138] An optical device according to Configuration 2, wherein the reflection suppressing structure is a periodic structure having a period that is twice the interval between the plurality of light emitting elements.

[0139] (Configuration 4)

[0140] An optical device according to configuration 3, wherein the reflection suppression structure has a row-direction cross-section and a column-direction cross-section, the row-direction cross-section is a row-direction cross-section of a plurality of light-emitting units having the same shape, and the column-direction cross-section is a column-direction cross-section of a periodic structure having a period that is twice the interval between the plurality of light-emitting elements.

[0141] (Configuration 5)

[0142] The optical device according to configuration 3 or 4, wherein the periodic structure has a rectangular shape.

[0143] (Configuration 6)

[0144] The optical device according to Configuration 3 or 4, wherein the periodic structure has a cylindrical lens shape.

[0145] (Configuration 7)

[0146] An optical device according to any one of Configurations 2 to 6, wherein the reflection suppression structure includes a multilayer film that transmits a wavelength of light emitted from the light emitting unit.

[0147] (Configuration 8)

[0148] An optical device according to any one of Configurations 2 to 7, wherein the reflection suppressing structure has a plurality of structures finer than a wavelength of light emitted from the light emitting unit.

[0149] (Configuration 9)

[0150] An optical device according to any one of Configurations 2 to 8, wherein the reflection suppression structure includes an absorption material that absorbs a wavelength of light emitted from the light emitting unit.

[0151] (Configuration 10)

[0152] The optical device according to configuration 1,

[0153] Wherein, the light splitting unit comprises:

[0154] a beam splitter comprising said reflector,

[0155] a first polarizer disposed between the light emitting unit and the beam splitter, and

[0156] a second polarizer disposed between the light receiving unit and the beam splitter, and

[0157] The first polarizer and the second polarizer extinguish light emitted from the light emitting unit and reflected by a surface of the beam splitter opposite to a surface facing the light emitting unit.

[0158] (Configuration 11)

[0159] The optical device according to configuration 1,

[0160] Wherein, the light splitting unit comprises:

[0161] a beam splitter comprising the reflector, and

[0162] a first polarizer, which is arranged between the light emitting unit and the beam splitter,

[0163] wherein the light from the light emitting unit that passes through the reflector is p-polarized light relative to a surface of the beam splitter that is opposite to a surface facing the light emitting unit across the reflector, and

[0164] The angle between the light passing through the reflector and the normal of the surface of the beam splitter opposite to the surface facing the light emitting unit is the Brewster angle.

[0165] (Configuration 12)

[0166] An in-vehicle system comprises an optical device according to any one of configurations 1 to 10, wherein the in-vehicle system determines the possibility of a collision between a vehicle and the object based on distance information of the object obtained by the optical device.

[0167] (Configuration 13)

[0168] The in-vehicle system according to configuration 12 further includes a control device configured to output a control signal to generate a braking force in the vehicle when it is determined that there is a possibility of a collision between the vehicle and the object.

[0169] (Configuration 14)

[0170] The in-vehicle system according to configuration 12 or 13 further includes a warning device configured to issue a warning to a user of the vehicle when it is determined that there is a possibility of a collision between the vehicle and the object.

[0171] (Configuration 15)

[0172] The in-vehicle system according to any one of configurations 12 to 14, further including a notification device configured to notify an external party of information related to the collision between the vehicle and the object.

[0173] (Configuration 16)

[0174] A movable device comprises the optical device according to any one of configurations 1 to 11, wherein the movable device is movable while holding the optical device.

[0175] (Configuration 17)

[0176] The movable device according to configuration 16 further includes a judgment unit configured to judge the possibility of collision with the object based on the distance information of the object acquired by the optical device.

[0177] (Configuration 18)

[0178] The movable device according to configuration 17 further includes a control unit configured to output a control signal for controlling movement of the movable device when it is determined that there is a possibility of collision with the object.

[0179] (Configuration 19)

[0180] The movable device according to configuration 17 or 18 further includes a warning unit configured to issue a warning to a user of the movable device when it is determined that there is a possibility of collision with the object.

[0181] (Configuration 20)

[0182] The movable device according to any one of configurations 17 to 19, further including a notification unit configured to notify an external party of information related to the collision with the object.

[0183] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

Claims

1. An optical device, comprising: a light emitting unit including a plurality of light emitting elements arranged in a two-dimensional shape; a light receiving unit including a plurality of light receiving elements; Imaging optical system; a light splitting unit disposed between the imaging optical system and the light receiving unit, the light splitting unit including a reflector; as well as an acquisition unit configured to acquire distance information of the object based on a time required from when the light emitting unit emits light until when the light receiving unit receives light reflected by the object, wherein the light emitting elements in the first row and the light emitting elements in the second row of the plurality of light emitting elements emit light at different times from each other in a time division manner, Wherein, the optical axis direction of the imaging optical system is not parallel to the normal direction of the reflector, wherein the light from the light emitting unit is reflected by the reflector to pass through the imaging optical system and then be reflected by the object, wherein the light reflected by the object passes through the imaging optical system to be transmitted through the reflector and thus received by the light receiving unit, wherein a first light emitting element among the plurality of light emitting elements and a first light receiving element among the plurality of light receiving elements are in a conjugate relationship via the reflector, and The light splitting unit is configured to suppress light from the first light emitting element from entering the first light receiving element.

2. The optical device according to claim 1, in, The light splitting unit includes a beam splitter, and the beam splitter includes the reflector, wherein the beam splitter comprises a reflection suppression structure on a surface opposite to a surface facing the light emitting unit, and The reflection suppressing structure suppresses light emitted from the first light emitting element, transmitted through the reflector, and reflected by the reflection suppressing structure from entering the first light receiving element.

3. The optical device according to claim 2, wherein: The reflection suppressing structure is a periodic structure having a period twice as long as an interval between the plurality of light emitting elements.

4. The optical device according to claim 3, wherein: The reflection suppression structure has a row direction cross section and a column direction cross section, the row direction cross section is a row direction cross section of multiple light-emitting units having the same shape, and the column direction cross section is a column direction cross section of a periodic structure with a period twice the interval of the multiple light-emitting elements.

5. An optical device according to claim 3 or 4, wherein: The periodic structure has a rectangular shape.

6. The optical device according to claim 3 or 4, wherein: The periodic structure has a cylindrical lens shape.

7. An optical device according to any one of claims 2 to 6, wherein: The reflection suppression structure includes a multilayer film that transmits a wavelength of light emitted from the light emitting unit.

8. An optical device according to any one of claims 2 to 7, wherein: The reflection suppressing structure has a plurality of structures finer than a wavelength of light emitted from the light emitting unit.

9. An optical device according to any one of claims 2 to 8, wherein: The reflection suppression structure includes an absorption material that absorbs a wavelength of light emitted from the light emitting unit.

10. The optical device according to claim 1, in, The light splitting unit comprises: a beam splitter comprising said reflector, a first polarizer disposed between the light emitting unit and the beam splitter, and A second polarizer is arranged between the light receiving unit and the beam splitter, and wherein the first polarizer and the second polarizer extinguish light emitted from the light emitting unit and reflected by a surface of the beam splitter opposite to a surface facing the light emitting unit.

11. The optical device according to claim 1, in, The light splitting unit comprises: a beam splitter comprising the reflector, and a first polarizer, which is arranged between the light emitting unit and the beam splitter, wherein the light from the light emitting unit that passes through the reflector is p-polarized light relative to a surface of the beam splitter that is opposite to a surface facing the light emitting unit across the reflector, and The angle between the light passing through the reflector and the normal of the surface of the beam splitter opposite to the surface facing the light emitting unit is the Brewster angle.

12. A vehicle-mounted system comprising the optical device according to any one of claims 1 to 10, wherein: The vehicle-mounted system determines the possibility of a collision between the vehicle and the object based on the distance information of the object obtained by the optical device.

13. The in-vehicle system according to claim 12, further comprising a control device configured to output a control signal to generate a braking force in the vehicle when it is determined that there is a possibility of a collision between the vehicle and the object.

14. The in-vehicle system according to claim 12 or 13, further comprising a warning device configured to issue a warning to a user of the vehicle when it is determined that there is a possibility of a collision between the vehicle and the object. 15 . The in-vehicle system according to claim 12 , further comprising a notification device configured to notify an external party of information related to the collision between the vehicle and the object.

16. A movable device comprising the optical device according to any one of claims 1 to 11, wherein: The movable device is capable of moving while holding the optical device. 17 . The movable device according to claim 16 , further comprising a determination unit configured to determine a possibility of collision with the object based on the distance information of the object acquired by the optical device. 18 . The movable device according to claim 17 , further comprising a control unit configured to output a control signal for controlling movement of the movable device when it is determined that there is a possibility of collision with the object. 19 . The movable device according to claim 17 , further comprising a warning unit configured to issue a warning to a user of the movable device when it is determined that there is a possibility of collision with the object. 20 . The movable device according to claim 17 , further comprising a notification unit configured to notify an external party of information related to the collision with the object.

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