Distance measuring device

Abstract

The present invention makes it possible to share a light receiving optical system used for detecting light emitted from a light emission unit and a light receiving optical system used for detecting light reflected from a subject.　This distance measuring device comprises: a light emission unit that generates emitted light; a first partial reflection unit that generates first reflected light and transmitted light from the emitted light; a second partial reflection unit that generates third reflected light from second reflected light obtained by reflecting the first reflected light, and transmits the transmitted light; and a light reception unit that receives the third reflected light and the transmitted light via the second partial reflection unit.

Description

Distance measurement device

[0001] This technology relates to a distance measurement device. More specifically, this technology relates to a distance measurement device capable of detecting emitted light emitted from a light emitting unit and reflected light reflected from a subject.

[0002] In a distance measurement device, when there is variation in the time from when an electrical signal for causing light emission is input to the light emitting unit until the light emitting unit emits light, there is a technique for detecting the emitted light emitted from the light emitting unit in order to determine the light emission timing. For example, a time measurement photodiode that receives light reflected by an object projected from a projection optical system via a light receiving optical system, and a PD output detection unit that detects a light receiving signal that is a voltage signal based on the output current of the time measurement photodiode are disclosed (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2017-161321

[0004] However, in the above-mentioned conventional technology, since a time measurement photodiode is provided separately from the PD output detection unit that detects the emitted light reflected from the subject, there is a risk of increasing the cost and size of the distance measurement device by that amount.

[0005] This technology has been created in view of such a situation, and an object thereof is to make it possible to share a light emitting optical system used for detecting emitted light emitted from a light emitting unit and a light receiving optical system used for detecting reflected light reflected from a subject.

[0006] This technology has been made to solve the above-mentioned problems, and a first aspect thereof is a distance measurement device including a light emitting unit that generates emitted light, a partial reflection unit provided with a plurality of partial reflection surfaces that respectively reflect a part of the emitted light, and a light receiving unit that receives the reflected light reflected through the partial reflection unit and the transmitted light transmitted through the partial reflection unit. This brings about the effect that the optical systems used for the reflected light reflected through the partial reflection unit and the transmitted light transmitted through the partial reflection unit are shared.

[0007] Furthermore, in the first aspect, the partial reflecting portion may include a first partial reflecting portion that generates a first reflected light and the transmitted light from the emitted light, and a second partial reflecting portion that generates a third reflected light from the second reflected light, which is obtained by reflecting the first reflected light, and also transmits the transmitted light. This results in the effect that a portion of the emitted light that has passed through the partial reflecting portion is received by the light receiving portion, while the reflected light reflected by the partial reflecting portion is reflected back by the subject and received by the light receiving portion via the partial reflecting portion.

[0008] Furthermore, in the first aspect, the partial reflective section may comprise four partial reflective surfaces that each reflect a portion of the emitted light and transmit a portion of the emitted light. This results in the scanning of a subject based on the rotation of the partial reflective section in the same direction, while the reflected light reflected through the partial reflective section and the transmitted light that passes through the partial reflective section are received by the light receiving section.

[0009] Furthermore, in the first aspect, the transmittance of the partial reflector may be less than the reflectance. This suppresses a decrease in the intensity of reflected light irradiated onto the subject through the partial reflector, while allowing the emitted light that has passed through the partial reflector to be monitored.

[0010] Furthermore, the first side may be provided with a Borygon mirror having the aforementioned partial reflector. This results in the subject being scanned based on the rotation of the Borygon mirror.

[0011] Furthermore, the first aspect may include a motor for rotating the partial reflector. This results in the subject being scanned based on the rotation of the partial reflector.

[0012] Furthermore, in the first aspect, the partial reflective surfaces may be at a 90° angle to each other. This has the effect of simplifying the optical system used for projecting emitted light and focusing transmitted light.

[0013] Furthermore, in the first aspect, the system may include a light-emitting optical system that projects the emitted light generated by the light-emitting unit onto the partial reflecting unit, and a light-receiving optical system that projects the reflected light reflected through the partial reflecting unit and the transmitted light that has passed through the partial reflecting unit onto the light-receiving unit. This results in the setting of optical paths for the emitted light, reflected light, and transmitted light.

[0014] Furthermore, in the first aspect, the partial reflecting portion may be positioned between the light-emitting optical system and the light-receiving optical system. This results in an optical path being set up in which a portion of the emitted light transmitted through the partial reflecting portion is received by the light-receiving portion, while at the same time, an optical path is set up in which the reflected light reflected by the partial reflecting portion, reflected by the subject, and returned light is received by the light-receiving portion via the partial reflecting portion.

[0015] Furthermore, in the first aspect, the optical axis of the light-emitting optical system and the optical axis of the light-receiving optical system may coincide with each other. This has the effect of simplifying the light-emitting optical system and the light-receiving optical system.

[0016] Furthermore, in the first aspect, the light-receiving unit may include a first light-receiving region for receiving reflected light and a second light-receiving region for receiving transmitted light. This results in the reflected light and transmitted light received by the light-receiving unit being separated and detected.

[0017] Furthermore, in the first aspect, the light-receiving unit may include a light-receiving area that is shared for receiving reflected light and transmitted light. This has the effect of simplifying the light-receiving areas for reflected and transmitted light.

[0018] Furthermore, the first side surface may include a light-gathering unit positioned between the partial reflective surfaces to collect the transmitted light that has passed through any of the partial reflective surfaces. This results in the function of setting the detection position of the transmitted light.

[0019] Furthermore, the first side surface may be provided with a support portion that supports the light-gathering portion so as to fix the position of the light-gathering portion between the partial reflective surfaces. This prevents the detection position of transmitted light from shifting due to the rotation of the partial reflective surfaces.

[0020] Furthermore, the first side surface may include a molding section for shaping the beam shape of the reflected light reflected by the partial reflection section. This improves the accuracy of reflection from the subject.

[0021] Furthermore, in the first aspect, the system may include a distance calculation unit that calculates the distance to the subject based on the timing of receiving the reflected light and the timing of receiving the transmitted light. This results in the calculation of the distance to the subject without depending on the timing of the emitted light.

[0022] Furthermore, in the first aspect, the system may include a light emission determination unit that determines the emission of light from the light-emitting unit based on the difference between the timing of receiving the reflected light and the timing of receiving the transmitted light. This allows for the determination of light emission from the light-emitting unit while unifying the detection positions for the reflected and transmitted light.

[0023] Furthermore, in the first aspect, the light-emitting unit may include a plurality of pixels arranged in accordance with the spread of the transmitted light. This results in the detection of light emission from the light-emitting unit while corresponding to the positional shift of the detection position of the transmitted light.

[0024] Furthermore, in the first aspect, the system may include a false detection determination unit that determines false detections of light emission from the light-emitting unit based on the light intensity distribution of the plurality of pixels. This results in the detection of light emission from the light-emitting unit while responding to the incidence of interference light.

[0025] Furthermore, in the first aspect, the device may be provided with a light emission detection unit that detects the emission of light from the light-emitting unit based on the light intensity distribution of the plurality of pixels. This improves the detection accuracy of the emission of light from the light-emitting unit while accommodating positional shifts in the detection position of the transmitted light.

[0026] This is a block diagram showing an example configuration of a distance measuring device according to the first embodiment. This is a block diagram showing an example configuration of a light detection unit according to the first embodiment. This is a diagram showing the light emission timing of the light emission unit according to the first embodiment. This is a perspective view showing an example configuration of the optical system of a distance measuring device according to the first embodiment. This is a perspective view showing the scanning operation of the optical system of a distance measuring device according to the first embodiment. This is a plan view showing an example of the receiving position of light emitted from the light emission unit and reflected light from the subject according to the first embodiment. This is a perspective view showing an example configuration of the optical system of a distance measuring device according to the second embodiment. This is a perspective view showing an example configuration of the optical system of a distance measuring device according to the third embodiment. This is a plan view showing an example of the receiving position of light emitted from the light emission unit and reflected light from the subject according to the third embodiment. This is a perspective view showing an example configuration of the optical system of a distance measuring device according to the fourth embodiment. This is a plan view showing an example of the receiving position of light emitted from the light emission unit and reflected light from the subject according to the fourth embodiment. This is a block diagram showing an example configuration of a light detection unit according to the fifth embodiment. This is a plan view showing an example of the receiving position of light emitted from the light emission unit and reflected light from the subject according to the fifth embodiment. This is a diagram showing an example of a histogram of the intensity of light received by a light emission detection pixel according to the fifth embodiment. This is a block diagram showing an example of the configuration of the light detection unit according to the sixth embodiment. This is a plan view showing an example of the light receiving positions for emitted light from the light-emitting unit and reflected light from the subject according to the sixth embodiment. This is a diagram showing an example of the histogram of the intensity of the received light for the light emission detection pixel and the distance measuring pixel according to the sixth embodiment. This is a block diagram showing an example of the configuration of the light detection unit according to the seventh embodiment. This is a plan view showing an example of the light receiving positions for emitted light from the light-emitting unit and reflected light from the subject according to the seventh embodiment. This is a diagram showing an example of the histogram of the intensity of the received light for the light emission detection pixel according to the seventh embodiment. This is a block diagram showing an example of the configuration of the light detection unit according to the eighth embodiment. This is a block diagram showing an example of the configuration of the light detection unit according to the ninth embodiment. This is a block diagram showing an example of the configuration of the light detection unit according to the tenth embodiment. This is a block diagram showing a schematic example of the configuration of the vehicle control system. This is an explanatory diagram showing an example of the installation position of the imaging unit.

[0027] The following describes the embodiments for implementing this technology (hereinafter referred to as "embodiments"). The description will proceed in the following order: 1. First embodiment (an example in which a partial reflective section is provided to guide the transmitted light, in which part of the emitted light has been transmitted, and the reflected light, in which part of the emitted light has been reflected, to a light-receiving section, and a light-collecting section is provided within the partial reflective section) 2. Second embodiment (an example in which a partial reflective section is provided to guide the transmitted light, in which part of the emitted light has been transmitted, and the reflected light, in which part of the emitted light has been reflected, to a light-receiving section, and a light-projection optical system is provided to project the emitted light onto the partial reflective section) 3. Third embodiment (an example in which a partial reflective section is provided to guide the transmitted light, in which part of the emitted light has been transmitted, and the reflected light, in which part of the emitted light has been reflected, to a light-receiving section, and a molding section is provided to shape the reflected light reflected by the partial reflective section) 4. 4. Embodiment 5 (An example in which a partial reflective section is provided to guide the transmitted light, in which a portion of the emitted light has been transmitted, and the reflected light, in which a portion of the emitted light has been reflected, to the light-receiving section, and the light-collecting section within the partial reflective section is removed) 5. Embodiment 6 (An example in which a partial reflective section is provided to guide the transmitted light, in which a portion of the emitted light has been transmitted, and the reflected light, in which a portion of the emitted light has been reflected, to the light-receiving section, and a false detection of light emission from the light-emitting section is determined) 6. Embodiment 7 (An example in which the light-receiving area of ​​the transmitted light, in which a portion of the emitted light has been transmitted, and the light-receiving area of ​​the reflected light, in which a portion of the emitted light has been reflected, to the light-receiving section, and the light intensity of the transmitted light and the light intensity of the reflected light are determined based on the difference in arrival time between the transmitted light and the reflected light) 7. Embodiment 8 (An example in which a partial reflective section is provided to guide the transmitted light, in which a portion of the emitted light has been transmitted, and the reflected light, in which a portion of the emitted light has been reflected, to the light-receiving section, and a positional shift in the light-receiving position of the transmitted light caused by the rotation of the partial reflective section is detected) Eighth embodiment (an example in which a partial reflective section is provided to guide the transmitted light, in which a portion of the emitted light has been passed through, and the reflected light, in which a portion of the emitted light has been reflected and is directed to the light-receiving section, and a light-collecting section is fixed within the partial reflective section) 9. Ninth embodiment (an example in which a partial reflective section is provided to guide the transmitted light, in which a portion of the emitted light has been passed through, and the reflected light, in which a portion of the emitted light has been reflected and is directed to the light-receiving section, and four partial reflective surfaces that each reflect a portion of the emitted light are provided in the partial reflective section)10. Tenth Embodiment (An example in which a partial reflecting section is provided to guide the transmitted light, which is partially transmitted by the emitted light, and the reflected light, which is partially reflected by the emitted light, to the light receiving section, and the light emitting section and light receiving section are arranged in an array, and the motor that rotates the partial reflecting section is removed) 11. Application Examples to Mobile Devices

[0028] <1. First Embodiment> Figure 1 is a block diagram showing an example of the configuration of a distance measuring device according to the first embodiment.

[0029] In the figure, the distance measuring device 100 performs distance measurement based on, for example, ToF (Time of Flight). The distance measuring device 100 may also be, for example, LiDAR (Light Detection and Ranging). Here, the distance measuring device 100 includes a partial reflector MB1. The partial reflector MB1 is provided with a plurality of partial reflecting surfaces that each reflect a portion of the emitted light LA. For example, the partial reflector MB1 can include partial reflectors M1 and M2, each provided with a partial reflecting surface. In this case, the distance measuring device 100 reflects a portion of the emitted light LA ​​with the partial reflector M1 and causes the reflected light LB1 to be incident on the subject 106. Then, the reflected light LB2 reflected from the subject 106 is reflected by the partial reflector M2, and the reflected light LB3 is detected by the light detection unit 112. In addition, the transmitted light LC, which is transmitted through the partial reflectors M1 and M2, is detected by the light detection unit 112. The distance measuring device 100 then calculates the distance to the subject 106 based on the timing of receiving the reflected light LB3 and the timing of receiving the transmitted light LC.

[0030] The distance measuring device 100 comprises a light-emitting drive unit 111, a light-emitting unit 101, a light-receiving optical system 102, a light detection unit 112, a distance calculation unit 113, and a motor drive unit 114. The distance measuring device 100 also comprises partial reflection units M1 and M2 and a motor 105.

[0031] The light-emitting drive unit 111 drives the light-emitting unit 101. At this time, the light-emitting drive unit 111 can apply an electrical signal to the light-emitting unit 101 to cause light emission. The light-emitting drive unit 111 may also pulse-drive the light-emitting unit 101.

[0032] The light-emitting unit 101 generates emitted light LA ​​in a predetermined wavelength range according to the drive of the light-emitting drive unit 111. The predetermined wavelength range may be in the visible range or the infrared range. The light-emitting unit 101 may be a laser diode or a laser using a passive Q switch. Lasers using a passive Q switch have a small pulse width and high output, which can increase the measurable distance. The light-emitting unit 101 may be equipped with light sources for multiple channels.

[0033] The partial reflective section M1 generates reflected light LB1 and transmitted light LC from the emitted light LA. At this time, the reflected light LB1 can be incident on the subject 106. The transmitted light LC can be incident on the partial reflective section M2.

[0034] The partial reflective section M2 generates reflected light LC3 from reflected light LC2 reflected from the subject 106, and also transmits transmitted light LC. At this time, the reflected light LB3 and transmitted light LC can be incident on the light-receiving optical system 102.

[0035] The reflective surfaces of each partial reflector M1 and M2 can form a 90° angle. The transmittance of each partial reflector M1 and M2 can be less than the reflectance. For example, the ratio of transmittance to reflectance of each partial reflector M1 and M2 may be 1:99. The partial reflectors M1 and M2 may be composed of polygonal mirrors, beam splitters, or a combination of half mirrors.

[0036] The motor 105 rotates the partial reflectors M1 and M2 together. The rotation of the partial reflectors M1 and M2 may be reciprocating. The rotation axis of the motor 105 can be set perpendicular to the mounting surface of the partial reflectors M1 and M2. The motor 105 may also be a LATM (Limited Angle Torque Motor).

[0037] The light-receiving optical system 102 images the reflected light LB3 and the transmitted light LC onto the light-receiving surface of the light-detecting unit 112. The light-receiving optical system 102 may also include lenses, optical filters, and apertures.

[0038] The light detection unit 112 receives reflected light LB3 reflected by the partial reflection unit MB1 and transmitted light LC that has passed through the partial reflection unit MB1. The light detection unit 112 may be equipped with a SPAD (Single Photon Avalanche Diode), or it may be equipped with an APD (Avalanche Photodiode) or SiPM (Silicon Photomultiplier) to receive the reflected light LB3 and transmitted light LC. The light detection unit 112 can generate a histogram based on a count value obtained by counting the time from when the light detection unit 112 receives the transmitted light LC until when it receives the reflected light LB3. The histogram can show the relationship between the number of SPAD responses (also called the reception frequency) and the distance to the subject 106. The distance to the subject 106 can be converted based on the count value obtained by the TDC (Time to Digital Converter) from when the light detection unit 112 receives the transmitted light LC until it receives the reflected light LB3.

[0039] The distance calculation unit 113 can determine the distance to the subject 106 based on the histogram generated by the light detection unit 112. At this time, the distance calculation unit 113 can calculate the distance to the subject 106 from the peak position of the histogram.

[0040] Figure 2 is a block diagram showing an example of the configuration of the light detection unit according to the first embodiment.

[0041] The light detection unit 112 includes a light receiving unit 103, a readout circuit 132, a TDC 133, a histogram generation unit 134, and a control unit 135.

[0042] The light-receiving unit 103 includes a light-receiving region that receives transmitted light LC and reflected light LB3. The light-receiving region may include multiple pixels. The pixels may be arranged in a matrix in the row direction and column direction. Each pixel may be provided with a SPAD. Each pixel may have a single SPAD or multiple SPADs.

[0043] The readout circuit 132 reads the transmitted light LC and reflected light LB3 from the light receiving area of ​​the light receiving unit 103 and outputs them to the TDC 133.

[0044] TDC133 measures the time difference from the reception of the transmitted light LC to the reception of the reflected light LB3, and converts the value into a digital value. At this time, the digital value can indicate the time difference between the reception timing of the transmitted light LC and the reception timing of the reflected light LB3. Note that TDC133 may be a multi-hit TDC that measures the times of the reception timings of the transmitted light LC and the reception timings of the reflected light LB3, where the emission intervals of the emitted light LA are different from each other.

[0045] The histogram generation unit 134 generates a histogram indicating the relationship between the time difference from the reception of the transmitted light LC to the reception of the reflected light LB3 and the reception frequency of the reflected light LB3.

[0046] The control unit 135 controls the light receiving unit 103, the readout circuit 132, TDC133, and the histogram generation unit 134. For example, the control unit 135 can control the operation timings of the light receiving unit 103, the readout circuit 132, TDC133, and the histogram generation unit 134 so that a histogram corresponding to the time difference from the reception of the transmitted light LC to the reception of the reflected light LB3 can be generated.

[0047] FIG. 3 is a diagram showing the emission timing of the light emitting unit according to the first embodiment.

[0048] In the figure, it is assumed that the light emitting unit 101 is a laser using a passive Q switch. At this time, the emitted light LA is emitted after the elapse of the delay time DLY after applying the drive current IDR to the laser using the passive Q switch. There is jitter JA in the emission timing of the emitted light LA after the application of the drive current IDR, and variations occur in the emission timing of the emitted light LA. Therefore, if the application timing to the drive current IDR is set as the zero point of the distance measurement, it will cause a decrease in the distance measurement accuracy. At this time, by adopting the reception timing of the transmitted light LC as the zero point of the distance measurement, it is possible to prevent a decrease in the distance measurement accuracy caused by variations in the emission timing of the emitted light LA.

[0049] FIG. 4 is a perspective view showing a configuration example of the optical system of the distance measurement device according to the first embodiment.

[0050] In the figure, a partial reflector MB1 is positioned between the light-emitting unit 101 and the light-receiving unit 103. Here, the transmitted light LC propagates inside the partial reflector MB1, while each reflected light LB1 to LB3 can propagate outside the partial reflector MB1. At this time, it is possible to prevent each reflected light LB1 to LB3 from entering the inside of the partial reflector MB1.

[0051] The partial reflective section MB1 can reciprocate based on the drive of the motor 105. In this case, the partial reflective section MB1 may be mounted on the motor 105. A light-gathering section 104 is arranged inside the partial reflective section MB1. In this case, the light-gathering section 104 can be positioned between the partial reflective sections M1 and M2. This allows the transmitted light LC to be focused without focusing the reflected light LB1 to LB3 at the light-gathering section 104. The light-gathering section 104 can focus the transmitted light LC that has passed through the partial reflective section M1. The light-gathering section 104 may be, for example, a Fresnel lens or a programmable metasurface.

[0052] A light-receiving optical system 102 is positioned between the partial reflective section MB1 and the light-receiving section 103. The light-receiving optical system 102 projects the transmitted light LC that has passed through the partial reflective section M2 and the reflected light LB3 that has been reflected by the partial reflective section M2 onto the light-receiving surface of the light-receiving section 103.

[0053] The partial reflective section MB1 is provided with partial reflective sections M1 and M2. The partial reflective surfaces of each partial reflective section M1 and M2 may be at a 90° angle to each other. This simplifies the configuration of the light-receiving optical system 102 and the light-collecting section 104.

[0054] Figure 5 is a perspective view showing the scanning operation of the optical system of the distance measuring device according to the first embodiment.

[0055] In the figure, by rotating the partial reflector MB1 via the motor 105, the reflected light LB1 can be scanned on the subject 106 along the scan direction SCA. Therefore, by using a single light source, distance measurement can be achieved at multiple locations on the subject 106.

[0056] Figure 6 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the first embodiment.

[0057] In the figure, the light receiving unit 103 is provided with a distance measuring area RB and a light emission detection area RC. Multiple pixels may be assigned to the distance measuring area RB. One pixel may be assigned to the light emission detection area RC. In this case, reflected light LB3 can be received in the distance measuring area RB, and transmitted light LC can be received in the light emission detection area RC.

[0058] As described above, in the first embodiment, partial reflectors M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving unit 103. This allows the transmitted light LC and the reflected light LB3 to be received by the light receiving unit 103, and the light receiving optical system 102 can be used for receiving the transmitted light LC emitted from the light emitting unit 101 and the reflected light LB3 reflected from the subject 106. Therefore, it is not necessary to provide a separate light receiving optical system for receiving the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system 102 used for receiving the transmitted light LC emitted from the light emitting unit 101, and the cost and size of the distance measuring device 100 can be reduced accordingly.

[0059] <2. Second Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is obtained by passing through a portion of the emitted light LA, and the reflected light LB2, which is obtained by reflecting a portion of the emitted light LA ​​and reflected from the subject 106, to the light receiving section 103. In this second embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is obtained by passing through a portion of the emitted light LA, and the reflected light LB2, which is obtained by reflecting a portion of the emitted light LA ​​and reflected from the subject 106, to the light receiving section 103, and a light projection optical system 201 is provided to project the emitted light LA ​​onto the partial reflective section M1.

[0060] Figure 7 is a perspective view showing an example of the optical system configuration of a distance measuring device according to the second embodiment.

[0061] In the figure, this distance measuring device includes an optical path conversion unit 204 in place of the light-gathering unit 104 of the first embodiment described above. Furthermore, this distance measuring device has a light-emitting optical system 201 added to the distance measuring device of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0062] The light projection optical system 201 projects the emitted light LA ​​generated by the light-emitting unit 101 onto the partial reflection unit MB1. At this time, the light projection optical system 201 may convert the emitted light LA ​​generated by the light-emitting unit 101 into parallel light and project it onto the partial reflection unit MB1. The light projection optical system 201 is positioned between the light-emitting unit 101 and the partial reflection unit MB1. At this time, the optical axis of the light projection optical system 201 and the optical axis of the light-receiving optical system 102 may coincide with each other. This simplifies the configuration of the light projection optical system 201 and the light-receiving optical system 102. The light projection optical system 201 may include a lens that focuses the emitted light LA ​​generated by the light-emitting unit 101, or it may include an optical filter that selects a desired wavelength range from the emitted light LA.

[0063] The optical path conversion unit 204 converts the optical path of the transmitted light LC that passes through the partial reflection unit MB1. The optical path conversion unit 204 is positioned between the partial reflection units M1 and M2. This allows the optical path of the transmitted light LC to be converted without converting the optical path of the reflected light LB1 to LB3 in the optical path conversion unit 204. For example, as shown in Figure 6, the optical path conversion unit 204 can cause the reflected light LB3 to be incident on the distance measuring area RB while the transmitted light LC is incident on the light emission detection area RC. The optical path conversion unit 204 may be a DOE (Diffractive Optical Element) or a prism.

[0064] As described above, in the second embodiment, partial reflection units M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving unit 103, and a light projection optical system 201 is provided to project the emitted light LA ​​onto the partial reflection unit M1. This makes it possible to set the light receiving position of the transmitted light LC, while the transmitted light LC and the reflected light LB3 can be received by the light receiving unit 103. For this reason, it is not necessary to provide a separate light receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system 102 used for detecting the transmitted light LC emitted from the light emitting unit 101, which reduces the cost and size of the distance measuring device 100, and also improves the light receiving accuracy of the transmitted light LC.

[0065] <3. Third Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is obtained by passing through a portion of the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this third embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is obtained by passing through a portion of the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and a molding section is provided to mold the reflected light LB1 reflected by the partial reflective section M1.

[0066] Figure 8 is a perspective view showing an example of the optical system configuration of a distance measuring device according to the third embodiment.

[0067] In the figure, this distance measuring device is modified by adding a light projection optical system 301 and a molding section 302 to the distance measuring device of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0068] The light projection optical system 301 projects the emitted light LA ​​generated by the light-emitting unit 101 onto the partial reflection unit MB1. At this time, the light projection optical system 301 may focus the emitted light LA ​​generated by the light-emitting unit 101 in a one-dimensional direction and project it onto the partial reflection unit MB1. The light projection optical system 301 is positioned between the light-emitting unit 101 and the partial reflection unit MB1. At this time, the optical axis of the light projection optical system 301 and the optical axis of the light-receiving optical system 102 may coincide with each other. This simplifies the configuration of the light projection optical system 301 and the light-receiving optical system 102. The light projection optical system 301 may be a cylindrical lens.

[0069] The molding section 302 shapes the beam shape of the reflected light LB1 reflected by the partial reflecting section MB1. The molding section 302 is positioned outside the partial reflecting section MB1. For example, the molding section 302 is positioned between the partial reflecting section M1 and the object 106. In this case, the molding section 302 may be positioned on the motor 105. The molding section 302 may be a DOE or a diffuser plate.

[0070] Figure 9 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the third embodiment.

[0071] In the figure, the reflected light LB3 is received in the distance measuring region RB, and the transmitted light LC is received in the light emission detection region RC. The reflected light LB3 may be received by multiple pixels in the distance measuring region RB. In this case, the reflected light LB3 spreads in a one-dimensional direction and is incident on the distance measuring region RB.

[0072] As described above, in the third embodiment, partial reflection sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. A molding section 302 is also provided to shape the reflected light LB1 reflected by the partial reflection section M1. This eliminates the need to provide a separate light receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system 102 used for detecting the transmitted light LC emitted from the light-emitting section 101. This reduces the cost and size of the distance measuring device 100 and improves the accuracy of the reflection from the subject 106.

[0073] <4. Fourth Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this fourth embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and the light concentrating section 104 within the partial reflective sections M1 and M2 is removed.

[0074] Figure 10 is a perspective view showing an example of the optical system configuration of a distance measuring device according to the fourth embodiment.

[0075] In the figure, the distance measuring device is modified by removing the light-gathering unit 104 from the distance measuring device of the first embodiment described above. In this case, the transmitted light LC that passes through the partial reflection unit MB1 spreads out and enters the light-receiving unit 103. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0076] Figure 11 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the fourth embodiment.

[0077] In the figure, the reflected light LB3 is received in the distance measuring area RB. The transmitted light LC is received in the distance measuring area RB as well as in the light emission detection area RC. The transmitted light LC may also be received by multiple pixels in the distance measuring area RB.

[0078] As described above, in the fourth embodiment, partial reflection sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and the light concentrating section 104 within the partial reflection sections M1 and M2 is removed. This eliminates the need to provide a separate light receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system 102 used for detecting the transmitted light LC emitted from the light emitting section 101, and also eliminates the need for the light concentrating section 104 within the partial reflection sections M1 and M2, thereby reducing the cost and size of the distance measuring device 100.

[0079] <5. Fifth Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 were provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this fifth embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and a false detection of light emission from the light emitting section 101 is determined.

[0080] Figure 12 is a block diagram showing an example of the configuration of the photodetector according to the fifth embodiment.

[0081] In the figure, this distance measuring device includes a light detection unit 512 instead of the light detection unit 112 of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0082] The light detection unit 512 has a false detection determination unit 501 added to the light detection unit 112 of the first embodiment described above. In addition, the light detection unit 512 includes a control unit 535 instead of the control unit 135 of the first embodiment described above. The other configurations of this light detection unit 512 are the same as those of the light detection unit 112 of the first embodiment described above.

[0083] The false detection determination unit 501 determines a false detection of light emission from the light-emitting unit 101 based on the light intensity distribution of a plurality of pixels provided on the light-receiving unit 103. At this time, the false detection determination unit 501 may also determine a false detection of light emission from the light-emitting unit 101 based on a comparison result between the light intensity distribution of normal light emission from the light-emitting unit 101 and the light intensity distribution at the time of detection of light emission from the light-emitting unit 101. A false detection of light emission from the light-emitting unit 101 may be an abnormality in the light emission from the light-emitting unit 101, or a false detection of interference light.

[0084] The control unit 535 controls the light receiving unit 103, the readout circuit 132, the TDC 133, the histogram generation unit 134, and the false detection determination unit 501. For example, the control unit 535 may perform a remeasurement or generate an alarm based on the false detection result from the false detection determination unit 501.

[0085] Figure 13 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the fifth embodiment.

[0086] In the figure, the light receiving unit 103 is provided with a distance measuring area RB2 and a light emission detection area RC2. Multiple pixels may be assigned to the distance measuring area RB and the light emission detection area RC2. In this case, reflected light LB3 can be received by the distance measuring area RB2, and transmitted light LC can be received by the light emission detection area RC2. The transmitted light LC may be received by multiple pixels in the light emission detection area RC2. In this case, the transmitted light LC spreads in a one-dimensional direction and is incident on the light emission detection area RC2.

[0087] Figure 14 shows an example of a histogram of the intensity of light received by a light emission detection pixel according to the fifth embodiment.

[0088] In the figure, the false detection determination unit 501 calculates an evaluation value D based on the normal transmitted light LC light intensity distribution Wi for each pixel i and the detection result Ci of the transmitted light LC for each pixel i, in order to determine if the emission of light from the light-emitting unit 101 is false. Note that pixel i indicates the position of a pixel arranged in one dimension. For example, the false detection determination unit 501 calculates an evaluation value D by subtracting a threshold T from the sum of the dot products of the normal transmitted light LC light intensity distribution Wi for each pixel i and the detection result Ci of the transmitted light LC for each pixel i. At this time, the evaluation value D can be given by the following equation 1. When the evaluation value D is outside the expected range, the false detection determination unit 501 determines that there is an abnormality in the emission of light from the light-emitting unit 101 or that it is due to interference light.

[0089]

[0090] As described above, in the fifth embodiment, partial reflection units M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving unit 103, and a false detection of light emission from the light emitting unit 101 is determined. As a result, it is not necessary to provide a separate light receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system 102 used for detecting the transmitted light LC emitted from the light emitting unit 101, thereby reducing the cost and size of the distance measuring device 100 and improving the distance measuring accuracy.

[0091] <6. Sixth Embodiment> In the first embodiment described above, partial reflectors M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving unit 103. In this sixth embodiment, the light receiving area of ​​the transmitted light LC, which is partially transmitted through the emitted light LA, and the light receiving area of ​​the reflected light LB3, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, are shared, and the light intensity of the transmitted light LC and the light intensity of the reflected light LB3 are determined based on the difference in arrival time between the transmitted light LC and the reflected light LB3.

[0092] Figure 15 is a block diagram showing an example of the configuration of a light detection unit according to the sixth embodiment.

[0093] In the figure, this distance measuring device includes a light detection unit 612 instead of the light detection unit 112 of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0094] The light detection unit 612 has an additional light emission determination unit 601 added to the light detection unit 112 of the first embodiment described above. Also, the light detection unit 612 includes a control unit 635 instead of the control unit 135 of the first embodiment described above. The other configurations of this light detection unit 612 are the same as those of the light detection unit 112 of the first embodiment described above.

[0095] The light emission determination unit 601 determines the light emission of the light emission unit 101 based on the difference between the light reception timing of the reflected light LB3 and the light reception timing of the transmitted light LC. At this time, the light emission determination unit 601 can determine the light emission of the light emission unit 101 based on the difference between the optical path length of the transmitted light LC and the optical path lengths of the reflected light LB2 and LB3. For example, the light emission determination unit 601 may determine the light reception timing of the transmitted light LC based on the position of the first peak in the histogram generated by the histogram generation unit 134, and determine the light reception timing of the reflected light LB3 based on the position of the next peak in the histogram generated by the histogram generation unit 134.

[0096] The control unit 635 controls the light receiving unit 103, the readout circuit 132, the TDC 133, the histogram generation unit 134, and the light emission determination unit 601. For example, the control unit 635 may perform distance measurement calculations based on the light emission determination unit 601's determination of the light receiving timing of the reflected light LB3 and the light receiving timing of the transmitted light LC.

[0097] Figure 16 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the sixth embodiment.

[0098] In the figure, the light receiving unit 103 is provided with a distance measuring area RB3 and a light emission detection area RC3. Multiple pixels may be assigned to the distance measuring area RB3 and the light emission detection area RC3. The same pixels are shared between the distance measuring area RB3 and the light emission detection area RC3. In this case, both reflected light LB3 and transmitted light LC can be received in both the distance measuring area RB3 and the light emission detection area RC3. The reflected light LB3 may be incident in a spot-like manner on both the distance measuring area RB3 and the light emission detection area RC3. The transmitted light LC may be incident in a one-dimensional manner, spreading out in the direction of both the distance measuring area RB3 and the light emission detection area RC3.

[0099] Figure 17 shows an example of a histogram of the intensity of light received by a light emission detection pixel and a distance measuring pixel according to the sixth embodiment.

[0100] In the figure, the histogram generation unit 134 generates two histograms, HS1 and HS2, corresponding to the transmitted light LC and the reflected light LB3, respectively. At this time, the time difference in the peak positions of the two histograms HS1 and HS2 can correspond to the distance DH to the subject 106.

[0101] The light emission determination unit 601 refers to the histogram generated by the histogram generation unit 134 in order to determine the light emission from the light emission unit 101. At this time, the light emission determination unit 601 can determine the reception timing of the transmitted light LC based on the peak position of histogram HS1, and determine the reception timing of the reflected light LB3 based on the peak position of histogram HS2.

[0102] Furthermore, when determining the timing of light reception of the transmitted light LC, the light emission determination unit 601 calculates an evaluation value D based on [Equation 1], and if the evaluation value D is outside the expected range, it may determine that there is an abnormality in the light emission of the light emission unit 101 or that it is due to interference light.

[0103] As described above, in the sixth embodiment, the light-receiving region of the transmitted light LC, through which a portion of the emitted light LA ​​has been transmitted, and the light-receiving region of the reflected light LB3, which has been reflected from the subject 106 by reflecting a portion of the emitted light LA, are shared, and the light intensity of the transmitted light LC and the light intensity of the reflected light LB3 are determined based on the difference in arrival times between the transmitted light LC and the reflected light LB3. This eliminates the need to provide a separate light-receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light-receiving optical system 102 used for detecting the transmitted light LC emitted from the light-emitting unit 101. Furthermore, it is possible to detect the transmitted light LC without needing to collect the transmitted light LC, thereby reducing the cost and size of the distance measuring device 100.

[0104] <7. Seventh Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this seventh embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and the emission of light from the light-emitting section 101 that reflects the positional shift of the light-receiving position of the transmitted light LC caused by the rotation of the partial reflective sections M1 and M2 is detected.

[0105] Figure 18 is a block diagram showing an example of the configuration of the light detection unit according to the seventh embodiment.

[0106] In the figure, this distance measuring device includes a light detection unit 712 instead of the light detection unit 112 of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0107] The light detection unit 712 has an additional light emission detection unit 701 added to the light detection unit 112 of the first embodiment described above. In addition, the light detection unit 712 includes a control unit 735 instead of the control unit 135 of the first embodiment described above. The other configurations of this light detection unit 712 are the same as those of the light detection unit 112 of the first embodiment described above.

[0108] The light emission detection unit 701 detects the emission of light from the light-emitting unit 101 based on the light intensity distribution of a plurality of pixels provided on the light-receiving unit 103. The light emission detection unit 701 receives encoder information ECN of the motor 105 as input. The encoder information ECN can indicate the rotation angle θ of the motor 105. At this time, the light emission detection unit 701 may detect the emission of light from the light-emitting unit 101 based on a comparison result between the light intensity distribution of normal emission from the light-emitting unit 101 and the light intensity distribution at the time of detection of emission from the light-emitting unit 101. At this time, the light intensity distribution can be provided according to the rotation angle θ of the motor 105.

[0109] The control unit 735 controls the light receiving unit 103, the readout circuit 132, the TDC 133, the histogram generation unit 134, and the light emission detection unit 701. For example, the control unit 735 may perform distance measurement or generate an alarm based on the detection result from the light emission detection unit 701.

[0110] Figure 19 is a plan view showing an example of the light receiving position of the light emitted from the light-emitting unit and the reflected light from the subject according to the seventh embodiment.

[0111] In the figure, the light receiving unit 103 is provided with a distance measuring area RB4 and a light emission detection area RC4. Multiple pixels may be assigned to the distance measuring area RB4 and the light emission detection area RC4. In this case, multiple pixels can be assigned to the light emission detection area RC4 in an array. Here, reflected light LB3 can be received by the distance measuring area RB4, and transmitted light LC can be received by the light emission detection area RC4. The transmitted light LC may be received by multiple pixels of the light emission detection area RC4. In this case, the transmitted light LC spreads in a two-dimensional direction and is incident on the light emission detection area RC2.

[0112] Figure 20 shows an example of a histogram of the intensity of light received by a light emission detection pixel according to the seventh embodiment.

[0113] In the figure, the light emission detection unit 701 calculates an evaluation value D(θ) based on the normal light intensity distribution Wi,j of the transmitted light LC for each pixel i,j and the detection results Ci,j of the transmitted light LC for each pixel i,j, in order to detect the light emission from the light emission unit 101. Note that pixels i,j represent the positions of pixels arranged in two dimensions. For example, the light emission detection unit 701 calculates an evaluation value D(θ) by subtracting a threshold T(θ) from the sum of the dot products of the normal light intensity distribution Wi,j of the transmitted light LC for each pixel i,j and the detection results Ci,j of the transmitted light LC for each pixel i,j. At this time, the evaluation value D(θ) can be given by the following equation 2. The false detection determination unit 501 can then determine that there is light emission from the light emission unit 101 when the evaluation value D(θ) is within the expected range.

[0114]

[0115] As described above, in the seventh embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. The emission of light from the light-emitting section 101 is detected, which reflects the positional shift of the light-receiving position of the transmitted light LC caused by the rotation of the partial reflective sections M1 and M2. This eliminates the need to provide a separate light-receiving optical system for detecting the reflected light LB3 reflected from the subject 106, in addition to the light-receiving optical system 102 used for detecting the transmitted light LC emitted from the light-emitting section 101. This reduces the cost and size of the distance measuring device 100, and improves the detection accuracy of the emission of light from the light-emitting section 101 while accommodating the rotation of the partial reflective sections M1 and M2.

[0116] <8. Eighth Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and a light concentrating section 104 is provided between the partial reflective sections M1 and M2. In this eighth embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and the light concentrating section 104 provided between the partial reflective sections M1 and M2 is fixed.

[0117] Figure 21 is a block diagram showing an example of the configuration of the light detection unit according to the eighth embodiment.

[0118] In the figure, this distance measuring device has a support section 801 and a support base 802 added to the distance measuring device of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0119] The support portion 801 supports the light-gathering portion 104 on the motor 105. In this case, the support portion 801 may suspend the light-gathering portion 104 from the motor 105. The support portion 801 may be configured in the shape of an arm. In this case, the support portion 801 can prevent the rotation of the light-gathering portion 104 caused by the drive of the motor 105.

[0120] The support base 802 fixes the support portion 801. The support base 802 may be installed on the housing or casing that houses the partial reflectors M1, M2 and the motor 105.

[0121] As described above, in the eighth embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and a light concentrating section 104 provided between the partial reflective sections M1 and M2 is fixed. This eliminates the need to provide a separate light receiving optical system 102 used for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system used for detecting the transmitted light LC emitted from the light emitting section 101, thereby reducing the cost and size of the distance measuring device 100, and preventing fluctuations in the light concentrating position of the transmitted light LC due to the rotation of the partial reflective sections M1 and M2.

[0122] <9. Ninth Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this ninth embodiment, a partial reflective section is provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103, and four partial reflective surfaces are provided in the partial reflective section, each reflecting a portion of the emitted light.

[0123] Figure 22 is a block diagram showing an example configuration of the light detection unit according to the ninth embodiment.

[0124] In the figure, this distance measuring device includes a partial reflecting unit MB2 instead of the partial reflecting unit MB1 of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0125] The partial reflective section MB2 comprises four partial reflective surfaces that each reflect a portion of the emitted light LA ​​and transmit a portion of the emitted light LA. The partial reflective section MB2 is formed by adding partial reflective sections M3 and M4 to the partial reflective sections M1 and M2 of the first embodiment described above. Each of the partial reflective sections M1 to M4 reflects a portion of the emitted light LA ​​and transmits a portion of the emitted light LA.

[0126] Each partial reflector M1 to M4 generates reflected light LB1 and transmitted light LC from the emitted light LA, and generates reflected light LC3 from the reflected light LC2 reflected from the subject 106. The reflective surfaces of each partial reflector M1 to M4 can form a 90° angle. The transmittance of each partial reflector M1 to M4 can be less than the reflectance. For example, the ratio of transmittance to reflectance of each partial reflector M1 to M4 may be 1:99. The partial reflectors M1 to M4 may be composed of polygonal mirrors, beam splitters, or a combination of half mirrors. In this case, the partial reflectors M1 to M4 may be arranged to form a regular quadrilateral prism.

[0127] As described above, in the ninth embodiment, a partial reflection section MB2 is provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. Four partial reflection surfaces are provided in the partial reflection section MB2, each reflecting a portion of the emitted light. This eliminates the need to provide a separate light receiving optical system 102 for detecting the reflected light LB3 reflected from the subject 106, in addition to the light receiving optical system used for detecting the transmitted light LC emitted from the light emitting section 101. This reduces the cost and size of the distance measuring device 100, and also allows the reflected light LC1 to be scanned onto the subject 106 based on the unidirectional rotation of the motor 105.

[0128] <10. Tenth Embodiment> In the first embodiment described above, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section 103. In this tenth embodiment, partial reflective sections M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving section, the light emitting section and the light receiving section are arrayed, and the motor that rotates the partial reflective section is removed.

[0129] Figure 23 is a block diagram showing an example of the configuration of the light detection unit according to the tenth embodiment.

[0130] In the figure, this distance measuring device includes a light-emitting array 1001 and a light-receiving array 1003 instead of the light-emitting unit 101 and light-receiving unit 103 of the first embodiment described above. In addition, the motor 105 is removed from this distance measuring device compared to the distance measuring device of the first embodiment described above. The other configurations of this distance measuring device are the same as those of the distance measuring device of the first embodiment described above.

[0131] The light-emitting array 1001 has light sources arranged in an array. Each light source in the light-emitting array 1001 generates emitted light LA ​​in a predetermined wavelength range. The light-emitting array 1001 may also be a laser array using passive Q switches.

[0132] The light-receiving array 1003 has light-receiving regions arranged in an array. Each light-receiving region of the light-receiving array 1003 may be assigned a distance-measuring region and a light-emitting detection region. In this case, reflected light LB3 can be received by each distance-measuring region of the light-receiving array 1003, and transmitted light LC can be received by each light-emitting detection region of the light-receiving array 1003.

[0133] As described above, in the tenth embodiment, partial reflection units M1 and M2 are provided to guide the transmitted light LC, which is partially transmitted through the emitted light LA, and the reflected light LB2, which is reflected from the subject 106 by reflecting a portion of the emitted light LA, to the light receiving unit. A light-emitting array 1001 and a light-receiving array 1003 are also provided, and the motor 105 for rotating the partial reflection units M1 and M2 is eliminated. This eliminates the need to provide a separate light-receiving optical system 102 used for detecting the reflected light LB3 reflected from the subject 106, in addition to the light-receiving optical system used for detecting the transmitted light LC emitted from the light-emitting unit 101. Furthermore, the motor 105 for rotating the partial reflection units M1 and M2 is unnecessary, thereby reducing the cost and size of the distance measuring device 100.

[0134] <11. Examples of Application to Mobile Devices> The technology relating to this disclosure (this technology) can be applied to various products. For example, the technology relating to this disclosure may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0135] Figure 24 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0136] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 24, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0137] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0138] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0139] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0140] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0141] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0142] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0143] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0144] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0145] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 24, the output devices are exemplified as an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0146] Figure 25 shows an example of the installation position of the imaging unit 12031.

[0147] In Figure 25, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0148] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0149] Figure 25 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0150] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0151] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, etc., that drives autonomously without driver operation, can be performed.

[0152] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0153] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0154] The above describes an example of a vehicle control system to which the technology described herein may be applied. The technology described herein can be applied to the imaging unit 12031 of the configuration described above. Specifically, for example, each distance measuring device of the above embodiment can be applied to the imaging unit 12031. By applying the technology described herein to the vehicle control system 12000, the cost and size of the imaging unit 12031 can be reduced.

[0155] The embodiments described above are merely examples for realizing the present technology, and there is a corresponding relationship between the matters in the embodiments and the inventive features in the claims. Similarly, there is a corresponding relationship between the inventive features in the claims and the matters in the embodiments of the present technology bearing the same name. However, the present technology is not limited to the embodiments and can be realized by making various modifications to the embodiments without departing from the gist of the technology. Furthermore, the effects described herein are merely examples and are not limiting, and other effects may also exist.

[0156] Furthermore, this technology can also be configured as follows: (1) A distance measuring device comprising: a light-emitting unit that generates emitted light; a partial reflective unit provided with a plurality of partial reflective surfaces that each reflect a portion of the emitted light; and a light-receiving unit that receives the reflected light reflected through the partial reflective unit and the transmitted light that has passed through the partial reflective unit. (2) The distance measuring device according to (1), wherein the partial reflective unit comprises: a first partial reflective unit that generates a first reflected light and the transmitted light from the emitted light; and a second partial reflective unit that generates a third reflected light from the second reflected light, which is obtained by reflecting the first reflected light, and also transmits the transmitted light. (3) The distance measuring device according to (1) or (2), wherein the partial reflective unit comprises four partial reflective surfaces that each reflect a portion of the emitted light and transmit a portion of the emitted light. (4) The distance measuring device according to any one of (1) to (3), wherein the transmittance of the partial reflective unit is less than the reflectance. (5) A distance measuring device according to any one of (1) to (4), comprising a polygon mirror provided with the partial reflecting portion. (6) A distance measuring device according to any one of (1) to (5), comprising a motor for rotating the partial reflecting portion. (7) A distance measuring device according to any one of (1) to (6), wherein the partial reflecting surfaces form a 90° angle with respect to each other. (8) A distance measuring device according to any one of (1) to (7), comprising a light projection optical system for projecting the emitted light generated by the light emission portion onto the partial reflecting portion, and a light receiving optical system for projecting the reflected light reflected through the partial reflecting portion and the transmitted light that has passed through the partial reflecting portion onto the light receiving portion. (9) A distance measuring device according to any one of (1) to (8), wherein the partial reflecting portion is positioned between the light projection optical system and the light receiving optical system. (10) A distance measuring device according to (9), wherein the optical axis of the light projection optical system and the optical axis of the light receiving optical system coincide with each other. (11) The distance measuring device according to any one of (1) to (10), wherein the light receiving unit comprises a first light receiving area for receiving reflected light and a second light receiving area for receiving transmitted light. (12) The distance measuring device according to any one of (1) to (11), wherein the light receiving unit comprises a light receiving area shared for receiving reflected light and receiving transmitted light.(13) A distance measuring device according to any one of (1) to (12), comprising a light-gathering unit positioned between the partial reflective surfaces and for gathering the transmitted light that has passed through any of the partial reflective surfaces. (14) A distance measuring device according to (13), comprising a support unit for supporting the light-gathering unit so as to fix the position of the light-gathering unit between the partial reflective surfaces. (15) A distance measuring device according to any one of (1) to (14), comprising a forming unit for shaping the beam shape of the reflected light reflected by the partial reflective surface. (16) A distance measuring device according to any one of (1) to (15), comprising a distance calculation unit for calculating the distance to a subject based on the timing of receiving the reflected light and the timing of receiving the transmitted light. (17) A distance-measuring device according to any one of (1) to (16), comprising a light emission determination unit for determining the emission of light from the light-emitting unit based on the difference between the timing of receiving the reflected light and the timing of receiving the transmitted light. (18) A distance measuring device according to any one of (1) to (17), wherein the light-emitting unit comprises a plurality of pixels arranged in accordance with the spread of the transmitted light. (19) The distance measuring device according to (18), further comprising a false detection determination unit that determines a false detection of light emission from the light-emitting unit based on the light intensity distribution of the plurality of pixels. (20) The distance measuring device according to (18), further comprising a light emission detection unit that detects light emission from the light-emitting unit based on the light intensity distribution of the plurality of pixels.

[0157] 100 Distance measuring device 101 Light-emitting unit 102 Light-receiving optical system 103 Light-receiving unit 104 Light-collecting unit 105 Motor 106 Subject M1, M2 Partial reflection unit 111 Light-emitting drive unit 112 Light detection unit 113 Distance calculation unit 114 Motor drive unit 132 Readout circuit 133 TDC 134 Histogram generation unit 135 Control unit

Claims

1. A distance measuring device comprising: a light-emitting unit that generates emitted light; a partial reflective unit provided with a plurality of partial reflective surfaces that each reflect a portion of the emitted light; and a light-receiving unit that receives reflected light reflected through the partial reflective unit and transmitted light that has passed through the partial reflective unit.

2. The distance measuring device according to claim 1, wherein the partial reflecting portion comprises a first partial reflecting portion that generates a first reflected light and the transmitted light from the emitted light, and a second partial reflecting portion that generates a third reflected light from the second reflected light obtained by reflecting the first reflected light, and transmits the transmitted light.

3. The distance measuring device according to claim 1, wherein the partial reflective portion comprises four partial reflective surfaces that each reflect a portion of the emitted light and each transmit a portion of the emitted light.

4. The distance measuring device according to claim 1, wherein the transmittance of the partial reflective portion is less than the reflectance.

5. The distance measuring device according to claim 1, comprising a polygon mirror provided with the partial reflective portion.

6. The distance measuring device according to claim 1, further comprising a motor for rotating the partial reflecting portion.

7. The distance measuring device according to claim 1, wherein the partial reflective surfaces form a 90° angle with respect to each other.

8. The distance measuring device according to claim 1, further comprising: a light projection optical system that projects the emitted light generated by the light-emitting unit onto the partial reflection unit; and a light receiving optical system that projects the reflected light reflected through the partial reflection unit and the transmitted light that has passed through the partial reflection unit onto the light receiving unit.

9. The distance measuring device according to claim 1, wherein the partial reflecting portion is disposed between the light-emitting optical system and the light-receiving optical system.

10. The distance measuring device according to claim 9, wherein the optical axis of the light-emitting optical system and the optical axis of the light-receiving optical system coincide with each other.

11. The distance measuring device according to claim 1, wherein the light receiving unit comprises a first light receiving region for receiving reflected light and a second light receiving region for receiving transmitted light.

12. The distance measuring device according to claim 1, wherein the light receiving unit comprises a light receiving area shared for receiving reflected light and receiving transmitted light.

13. The distance measuring device according to claim 1, further comprising a light-gathering unit positioned between the partial reflective surfaces and for collecting the transmitted light that has passed through any of the partial reflective surfaces.

14. The distance measuring device according to claim 13, further comprising a support portion that supports the light-gathering portion such that the position of the light-gathering portion is fixed between the partial reflective surfaces.

15. The distance measuring device according to claim 1, further comprising a molding unit for shaping the beam shape of the reflected light reflected by the partial reflection unit.

16. The distance measuring device according to claim 1, further comprising a distance calculation unit that calculates the distance to a subject based on the timing of receiving the reflected light and the timing of receiving the transmitted light.

17. The distance measuring device according to claim 1, further comprising a light emission determination unit that determines the emission of light from the light emission unit based on the difference between the timing of receiving the reflected light and the timing of receiving the transmitted light.

18. The distance measuring device according to claim 1, wherein the light-emitting unit comprises a plurality of pixels arranged in accordance with the spread of the transmitted light.

19. The distance measuring device according to claim 18, further comprising a false detection determination unit that determines a false detection of light emission from the light-emitting unit based on the light intensity distribution of the plurality of pixels.

20. The distance measuring device according to claim 18, further comprising a light emission detection unit that detects the emission of light from the light emission unit based on the light intensity distribution of the plurality of pixels.

Images