Lighting device, distance measuring device, and mobile device

Abstract

In a light source used in a distance measuring device, we want to appropriately control the density of the emitted light. [Solution] The light projection device is characterized by comprising a light source equipped with a light-emitting element, an optical element on which microlenses are arranged, an image-side telecentric lens that projects photons emitted by the light-emitting element onto a target, and control means for controlling the optical path length between the microlenses and the image-side telecentric lens.

Description

[Technical Field]

[0001] This invention relates to a light projection device, a distance measuring device, and a mobile device. [Background technology]

[0002] A distance measurement method known as TOF (Time-Of-Flight) is known to measure the distance to an object by measuring the time difference between the time light is shone on it and the time reflected light is detected.

[0003] Patent Document 1 discloses a configuration in which a light-emitting element and a light-receiving element are arranged in two dimensions, light is shone onto an object through an imaging lens, and reflected light is received to acquire three-dimensional distance information without a drive unit.

[0004] To measure distance, it is necessary to detect signal light originating from emitted light rather than ambient light such as sunlight. Therefore, it is desirable that the signal light not be drowned out by ambient light. For this reason, it is desirable to increase the light energy or light density of the projected light to prevent the signal light from being drowned out by ambient light.

[0005] On the other hand, if the projected image is made smaller (higher light density), the area illuminated by the projected light on the target becomes smaller, which may result in the projected image not hitting the target at all (reduced resolution). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2019-60652 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 does not address the above-mentioned issues regarding the intensity of the signal light or the density of the projected image.

[0008] In view of the above problems, an object of the present invention is to provide a light projecting device, a distance measuring device, and a mobile device that have higher distance measuring performance and higher resolution by appropriately controlling the density of light projected for distance measurement.

Means for Solving the Problems

[0009] In order to solve the above problems, the light projecting device of the present invention is characterized by including a light source having a light emitting element, an optical element on which a microlens is disposed, an image-side telecentric lens that projects light onto photons emitted by the light emitting element, and control means for controlling the optical path length between the microlens and the image-side telecentric lens.

Effects of the Invention

[0010] According to the present invention, it is possible to achieve both high distance measuring performance and high resolution by appropriately controlling the density of light projected for distance measurement.

Brief Description of the Drawings

[0011] [Figure 1] It is a block diagram of the distance measuring device in the first embodiment. [Figure 2] It is a schematic diagram of the light source unit in the first embodiment. [Figure 3] It is a schematic diagram of the light receiving element array in the first embodiment. [Figure 4] It is a diagram showing the state of the projected light in the first embodiment. [Figure 5] [[ID=三十五]]It is a diagram showing the state in which the projected light is projected onto the object in the first embodiment. [Figure 6] It is a schematic diagram of the histogram in the first embodiment. [Figure 7] It is a schematic diagram of the histogram according to the subject distance in the first embodiment. [Figure 8] It is a schematic diagram showing the relationship between the schematic diagram of the histogram according to the subject distance in the first embodiment and the threshold value Sth. [Figure 9]This figure shows the relationship between the projected image, the received image, and the resolution in the first embodiment. [Figure 10] This is a diagram showing the configuration of an in-vehicle system equipped with a rangefinder according to the first embodiment. [Figure 11] This is a schematic diagram of a mobile device equipped with a distance measuring device according to the first embodiment. [Figure 12] This flowchart shows an example of the operation of an in-vehicle system equipped with a rangefinder according to the first embodiment. [Modes for carrying out the invention]

[0012] [First Embodiment] A specific example of the configuration of the distance measuring device of the present invention will be described below with reference to the figures, as the first embodiment.

[0013] [Overall configuration of ranging device] Figure 1 is a schematic diagram showing an example configuration of the distance measuring device according to this embodiment.

[0014] The distance measuring device 1 consists of a light projection unit 110 (light projection device), a measurement unit 120, an image-side telecentric lens 130, an overall control unit 140, and a beam splitter 150. In this embodiment, as shown in Figure 1, the distance measuring device 1 uses the beam splitter 150 to share the same image-side telecentric lens 130 for light emission and light reception. In a binocular configuration where the optical system on the light emission side and the optical system on the light reception side are separate systems, light emitted from a light-emitting element is projected through the image-side telecentric lens, reflected by the object, and returns through the image-side telecentric lens. At this time, the optical path of the reflected light changes according to the distance to the object. Therefore, the imaging position on the light-receiving element changes according to the distance to the object, which may cause distance dependence of the distance measuring accuracy. On the other hand, in the distance measuring device 1 of this embodiment, the same optical path can be used for light emission and light reception. Therefore, according to this embodiment, it is possible to eliminate the object distance dependence of the distance measuring accuracy caused by the binocular configuration described above.

[0015] The light projection unit 110 consists of a light source unit 113 comprising a light-emitting section and optical elements, and a light source control unit 114. The light-emitting section consists of a light-emitting element array 210 in which light-emitting elements 211 are arranged in a two-dimensional manner.

[0016] The measurement unit 120 consists of a light receiving unit 121, a TDC (Time-to-Digital Converter) array unit 122, a signal processing unit 123, and a measurement control unit 124.

[0017] Each of the light-emitting elements 211 within the light source unit 113 emits pulsed light, projecting pulsed light into space via the image-side telecentric lens 130. The pulsed light emitted from each separate light-emitting element 211 is projected to different angles of view in space. The projected light illuminates the subject (object), and a portion of the light reflected by the subject is received by the light-receiving unit 121 via the image-side telecentric lens 130. The time from when the light-emitting element 211 emits light until it is received by the light-receiving unit 121 is the time of flight (TOF), and this time is measured by the TDC array unit 122. However, a single measurement cannot eliminate noise components such as ambient light and dark counts, and the distance measurement error becomes large due to the influence of noise in the measurement circuit. Therefore, the time measurement from emission to reception is repeated, and the signal processing unit 123 creates a histogram of the measurement results to remove noise components and average the measurement results. By substituting the time of flight (TOF) obtained in this way into equation (1) below, the distance L to the subject can be determined with high accuracy. Here, c is the speed of light.

[0018]

number

[0019] [Light source unit] Figure 2 shows a schematic diagram of an example of a light source unit 113 according to this embodiment. The light source unit 113 includes a light-emitting element array 210 as the light-emitting section, and a collimator lens array 220 and a microlens array 230 as optical elements.

[0020] The light-emitting element array 210 consists of VCSELs (Vertical Cavity Surface Emitting Lasers) arranged in a two-dimensional array on a substrate as light-emitting elements 211.

[0021] The light-emitting element 211 is not limited to VCSELs, but is preferably one that can be integrated in a one-dimensional or two-dimensional array, such as an end-face emitting laser or an LED (light-emitting diode). As for the light-emitting element array 210, if an end-face emitting laser is used instead of a VCSEL array as the light-emitting element 211, a laser bar arranged in one dimension on a substrate, or a laser bar stack that is stacked to form a two-dimensional light-emitting element array, can be used. If an LED is used as the light-emitting element, a substrate in which LEDs are arranged in a two-dimensional array can be used.

[0022] In the distance measuring system of the present invention, it is preferable to set the wavelength of light emitted by the light-emitting element 211 to the near-infrared band in order to suppress the influence of ambient light. However, it is not limited to this. VCSELs are fabricated using semiconductor processes with materials used in conventional end-emitting lasers and surface-emitting lasers, and when configured to emit light with wavelengths in the near-infrared band, GaAs-based semiconductor materials can be used as the main material. In this case, the dielectric multilayer film forming the DBR (distributed reflection) mirror constituting the VCSEL can be made of two thin films made of materials with different refractive indices stacked alternately and periodically (GaAs / AlGaAs). The wavelength of the emitted light can be changed by adjusting the elemental combination and composition of the compound semiconductor.

[0023] Each VCSEL in a VCSEL array is equipped with electrodes for injecting current and holes into its active layer. By controlling the injection timing, it is possible to emit arbitrary pulsed light or modulated light. For this purpose, a light source control unit 114 is provided, which can, for example, independently drive each VCSEL as a light-emitting element 211, or drive each row, column, or specific area of ​​the VCSEL array.

[0024] Light emitted from the VCSEL as a light-emitting element 211 is normally divergent due to diffraction at the aperture of the VCSEL. Therefore, a collimator lens array 220 is configured in which collimator lenses 221 are arranged in a two-dimensional array to control the divergence angle of the divergent light or to convert it into parallel light. In this embodiment, the collimator lenses 221 constituting the collimator lens array 220 are arranged in a one-to-one correspondence with each light-emitting element 211. The light emitted from the VCSEL array collimated by the collimator lens array 220 is converted, for example, into parallel light perpendicular to the VCSEL array substrate. Note that in cases where the radiation angle from the VCSEL is small due to the aperture diameter, the collimator lenses 221 may be omitted.

[0025] Furthermore, the microlenses 231 constituting the microlens array 230 are arranged in a one-to-one correspondence with each light-emitting element 211, and the microlenses 231 and the image-side telecentric lens 130 are configured to form an afocal system.

[0026] [Photodetector] Figure 3 shows a schematic diagram of the light-receiving element array 310 according to this embodiment. The light-receiving element array 310 is composed of a plurality of light-receiving elements 311. Furthermore, each light-receiving element 311 is composed of a plurality of sub-light-receiving elements 312. Each of the sub-light-receiving elements can be driven independently.

[0027] Furthermore, although the light-receiving element 311 is composed of 5 × 5 sub-light-receiving elements in Figure 3, it may also be composed of m × n (where m and n are natural numbers) sub-light-receiving elements.

[0028] [Light projection and light reception] Figure 4 illustrates the appearance of the projected image after the light emitted from the light-emitting element 211 has passed through the image-side telecentric lens 130. This embodiment is characterized by the provision of a refractive index element 160 between the microlens array 230 and the image-side telecentric lens 130, but the effect of providing the refractive index element 160 on the projected image will be described later.

[0029] The microlens 231 and the image-side telecentric lens 130 constitute an afocal system. Therefore, when light is projected from the image-side telecentric lens, it is projected at an angle corresponding to the image height (the positional relationship between the microlens 231 and the image-side telecentric lens 130) and is projected parallel to the image. Thus, the width d of the projected light. b The light (in three dimensions, thickness) is projected with the same width (in three dimensions, thickness) at any distance from the image-side telecentric lens 130 to the subject (independent of the distance to the subject). However, the emission diameter on the microlens is p, and the focal length of the microlens 231 is f. M The focal length of the image-side telecentric lens 130 is f L Therefore, the width d of the projected light b The width of the projected light d is expressed by the following equation (2). Here, if p is greater than the pitch of the microlenses, then p is limited by the pitch of the microlenses. b If the width of the projected light d is greater than the pupil diameter of the image-side telecentric lens 130, b This is limited by pupil diameter.

[0030]

number

[0031] The collimating lens 221 between the light-emitting element 211 and the microlens 231 collimates the spread of the light emitted from the light-emitting element 211.

[0032] Next, referring to FIGS. 5(a) to 5(c), the state of the projection light described in FIG. 4 as seen on the subject will be described. FIGS. 5(a) to 5(c) are diagrams showing the state in which the projection light is projected onto the subject (object) 501. In FIGS. 5(a) to 5(c), the projection light is projected onto the subject 501 as a projection image 502. The projection image size d b in FIGS. 5(a) to 5(c) and the width d b of the projection light in FIG. 4 are equal to each other. The subject 501 is shown as FIGS. 5(a), (b), and (c) in the order from the closest to the image-side telecentric lens 130.

[0033] As shown in FIGS. 5(a) to 5(c), as the distance from the image-side telecentric lens 130 increases, the projection light interval increases, but the projection image size d b does not change. That is, the interval between the projection lights (projection light interval) irradiated onto the subject 501 through the image-side telecentric lens 130 changes according to the distance to the subject 501. On the other hand, the width of each of the plurality of projection lights (projection image size d b ) does not change according to the distance to the subject 501. Thereby, the light emitted from a certain light-emitting element 211 can be made to be received only by a specific light-receiving element 311 in the light-receiving element array 310 as shown in FIG. 5(d), and it is possible to make a one-to-one correspondence between the light-emitting element 211 and the light-receiving element 311. For this reason, it is possible to perform sequential driving in which only a part of the plurality of light-emitting elements 211 emits light and only the light-receiving elements corresponding to the light-emitting elements 211 that emit light among the plurality of light-receiving elements are driven. Thereby, one TDC can be shared by a plurality of light-receiving elements, and the pixel size can be reduced, which is effective for high resolution.

[0034] [Histogram] Conceptual diagrams of histograms are shown in FIGS. 6(a), (b), and (c). FIG. 6(a) is a histogram consisting only of photons derived from the signal light, and FIG. 6(b) is a histogram consisting only of photons derived from the ambient light.

[0035] In the histogram of Figure 6(a), which consists of photons originating from signal light, the number of photons accumulates over a time (distance) window corresponding to the emission time of the light-emitting element 211, whereas the ambient light photons are counted randomly over time (distance).

[0036] In the above, histograms are shown separately for photons originating from signal light and photons originating from ambient light. However, in reality, signal light and ambient light cannot be distinguished, so a histogram is obtained that combines the histograms in Figure 6(a) and Figure 6(b), as shown in Figure 6(c).

[0037] [Incorrect distance measurement] Figure 7(a) shows a conceptual diagram of the histogram when the subject is close, and Figure 7(b) shows a conceptual diagram of the histogram when the subject is far away. For convenience, the counts from signal light and the counts from ambient light are shown separately here, but in reality, the histograms obtained do not distinguish between the two.

[0038] In Figure 7(a), where the subject distance is close, the bin where the count originating from the signal light is detected is the bin with the highest count, so the subject distance can be calculated correctly. For example, the distance to the bin with the highest count can be used directly as the subject distance, or the distance to the bins before and after the bin with the highest count can be used.

[0039]

number

[0040] The subject distance may be calculated as shown above, or by other methods. Here, LSB peak This is the distance measurement result, LSB C0 C0 is the distance indicated by the bin where the count reaches its maximum, and C0 is the maximum count (LSB). C0 (Bin count value), C1 and C2 are LSB C0 These are the count values ​​of the bins before and after this point.

[0041] On the other hand, in Figure 7(b), where the subject distance is far, the bin where counts originating from ambient light are detected is the bin with the highest count. Therefore, if the subject distance is calculated using that bin, there is a possibility of calculating an incorrect subject distance (= mismeasurement).

[0042] To prevent mismeasurements like those described above, a threshold Sth may be set for the histogram counts. For example, if there are sufficient counts originating from signal light, as in the histogram in Figure 8(a), extracting only the counts above a certain threshold Sth will result in Figure 8(a'), leaving only the counts originating from signal light. On the other hand, as in Figure 8(b), if the counts originating from signal light are equal to or less than the counts originating from ambient light, extracting only those above a certain threshold Sth will result in zero counts, as in Figure 8(b'), and by considering this as impossible to measure, mismeasurements can be prevented.

[0043] While a larger threshold Sth can prevent mismeasurements, it also cuts out counts originating from signal light. Therefore, under conditions where it is difficult to obtain counts originating from signal light, such as when the subject is far away, the likelihood of mismeasurement increases. On the other hand, a smaller threshold Sth reduces the likelihood of mismeasurement but increases the likelihood of mismeasurement. It is desirable to set the threshold Sth considering the luminescence energy of the light-emitting element 211, the pupil diameter of the image-side telecentric lens 130, and the quantum efficiency of the photodetector 311.

[0044] Therefore, in this embodiment, since the influence of ambient light depends on weather and location, the threshold Sth is made arbitrarily set taking into account the influence of ambient light. The overall control unit 140 controls the light source control unit 114 and the measurement control unit 124, and by taking measurements while the light source unit 113 is not emitting light, a histogram of ambient light only is obtained, and the threshold Sth is set from the result. However, the system is not limited to this, and as shown in Figure 9, a photometric unit 900 may be provided to directly measure the influence of ambient light, and the threshold Sth may be set arbitrarily from the result.

[0045] [Sub-photodetector and resolution] Using Figure 3, it was explained that the light-receiving element 311 is composed of one or more sub-light-receiving elements 312. Furthermore, using Figure 5, it was explained that the light emitted from a certain light-emitting element 311 can be received by a specific light-receiving element 311.

[0046] The light-receiving element 311 is composed of a plurality of sub-light-receiving elements 312, and the plurality of sub-light-receiving elements can be driven independently of each other in their light-receiving operation. In this case, the signal processing unit 123 may use a histogram that combines the output signals from the plurality of sub-light-receiving elements 312 within the light-receiving element 311, or it may use a different histogram for each of the output signals from the plurality of sub-light-receiving elements 312. In other words, the plurality of sub-light-receiving elements 312 may be grouped together as a single pixel, or each sub-light-receiving element 312 may be treated as a single pixel.

[0047] In this case, when the sub-photodetectors 312 are grouped by pixels, a histogram with a higher count value (vertical axis value of the histogram) is obtained for each grouped pixel. This is advantageous for subjects that are far away or have low reflectivity, where the probability of receiving photons originating from the signal light from the light-emitting element 311 is low.

[0048] On the other hand, pixel aggregation reduces the resolution by the amount of pixel aggregation. For subjects that are close or have high reflectivity, the probability of receiving photons originating from signal light is high, so even without pixel aggregation, it is sometimes possible to obtain a histogram with a peak at the subject position that allows for accurate distance measurement. In such cases, by not aggregating pixels and treating the sub-photodetector 312 as one pixel, the resolution equivalent to that of the sub-photodetector can be obtained.

[0049] In other words, when you want to improve (enhance) the distance measurement performance, you can combine pixels, and when you want to improve (enhance) the resolution, you can avoid combining pixels.

[0050] [Projection image size and resolution] Using Figures 4 and 5, by projecting the light emitted from the light-emitting element 211 using an afocal optical system, the projected image size d remains the same regardless of the subject distance. b We explained that it can project light with high light density, and therefore, high environmental resistance can be expected.

[0051] At this time, the projected image size d b In some cases, the projected light may not hit the subject. For example, as shown in Figure 9(a), the projected image size d is used for high ambient light tolerance. b Reducing the size of the projection image d will decrease the area of ​​light illumination on the subject, which may result in the projection light not hitting the subject at all, or only hitting a part of the subject. Figure 9(b) shows Figure 9(a) as viewed on the light-receiving element array 310. b The corresponding image size d s This shows how a light-receiving image 503, which has the characteristics of a sub-photodetector 312, is received across multiple sub-photodetectors 312. In this case, if the sub-photodetector 312 over which the light-receiving image spans is designated as a signal light-receiving sub-photodetector 901, then distance measurement performance can be improved by grouping the signal light-receiving sub-photodetectors 901 into pixels.

[0052] However, there are also sub-photodetectors 312 that do not overlap with the received image. Therefore, if the sub-photodetectors 312 are treated as one pixel, as shown in the distance measurement image in Figure 9(c), the region where the signal light cannot be received will measure ambient light (i.e., the distance measurement result will not be correct), or it will be a region where distance measurement is not possible, making it unsuitable for high resolution.

[0053] On the other hand, as shown in Figure 9(d), the projected image size d b Increasing the size of the light source increases the area of ​​light illumination on the subject, and it is expected that the projected light will hit a larger area of ​​the subject. Figure 9(e) is a view of Figure 9(d) on the light-receiving element array 310, and since the received image 503 spans all the sub-light-receiving elements 312, if each of the sub-light-receiving elements 312 is treated as one pixel, a high-resolution distance measurement image like Figure 9(f) can be obtained.

[0054] [Refractive index and image size] Using Figure 9(a), the image size d s When the size is small, the tolerance to ambient light is high, and the image size d is measured using Figure 9(b). s We explained that when the value is large, it is possible to measure distance with high resolution by treating each of the sub-photodetectors 311 as one pixel.

[0055] However, if the optical system is fixed, the projected image size d b Since it is also fixed, the light-receiving image size d s This is uniquely determined by conditions such as subject distance and subject reflection characteristics. In other words, the projected image size d b Should we prioritize ambient light resistance by reducing the size of the projected image d? b You can only choose one option: either increase the size and prioritize resolution, or do not choose the other.

[0056] Therefore, in this embodiment, by providing a refractive index element 160 in the optical path of the optical system formed by the light-emitting element array 210, the microlens array 230, and the image-side telecentric lens 130, the optical path length between the two elements is controlled, and the projected image size d b The configuration allows for variable refractive index. The refractive index element 160 may be removable from the optical path, or it may be configured so that the refractive index can be changed in each region using a liquid crystal ND or the like.

[0057] The refractive index of the refractive index element 160 can be controlled by the refractive index control unit 161. For example, the refractive index element 160 can be configured to be insertable and removable from the optical path. Alternatively, the refractive index of the refractive index element 161 can be configured, for example, with a liquid crystal ND filter, and can be changed by the user. Furthermore, the refractive index element 60, whose refractive index can be controlled, such as a liquid crystal ND filter, can be automatically changed via the overall control unit 140.

[0058] Furthermore, in order to achieve the objectives of the present invention, the projected image size d bSince the optical path length can be changed to make the refractive index variable, the method is not limited to inserting a refractive index element 160 to make the refractive index variable. For example, instead of arranging a refractive index element 160, the distance in the optical axis direction between the microlens array 230 and the image-side telecentric lens 130 can be changed. For example, the optical path length can be made variable by providing a drive unit that enables the microlens array 230 to move in the optical axis direction. Of course, both the refractive index element 160 and the drive unit for the microlens array 230 may be provided.

[0059] (Focus control) In this embodiment, the focus of the image-side telecentric lens 130 is configured to be variable. By changing the focus of the image-side telecentric lens 130, the size of the received image 503 can be changed. s It is possible to change this. In this embodiment, the focus of the image-side telecentric lens 130 can be automatically adjusted by the focus control unit 170, but it may also be configured to be manually adjustable by the user.

[0060] On the other hand, since the microlens array 230 and the image-side telecentric lens 130 constitute an afocal system, it is necessary to appropriately set the optical path length between the microlens array 230 and the image-side telecentric lens 130. Therefore, when the focus of the image-side telecentric lens 130 is changed, the projected image size d b Since this also changes, it is desirable to insert or remove the refractive index element 160, or to change the refractive index of the refractive index element 160 as well, in order to adjust (control) the desired projected image size.

[0061] With this configuration, the projected image size d b and the size of the received image d s It is possible to change each of these.

[0062] As described above, in this embodiment, by appropriately controlling the density of the light emitted in the light projection device used in the distance measuring device, it is possible to achieve both high distance measuring performance and high resolution according to the target.

[0063] (modified version) In this embodiment, the image-side telecentric lens 130 is a fixed focal length prime lens, but it is not limited to this; it may also be a zoom lens with a variable focal length, or a prime lens that is interchangeable. In other words, it may be possible to use image-side telecentric lenses with different focal lengths. By using image-side telecentric lenses with different focal lengths (zoom), it is possible to change the angle of view.

[0064] To configure an afocal system, it is necessary to appropriately set the optical path length between the microlens array 230 and the image-side telecentric lens 130. If the focal length (zoom) of the image-side telecentric lens 130 changes, the optical path length between the microlens array 230 and the image-side telecentric lens 130 may change. Therefore, when replacing lenses or changing the zoom of a zoom lens, it is desirable to also insert or remove the refractive index element 160, change the refractive index of the refractive index element 160, or change the focus of the image-side telecentric lens 130.

[0065] [In-vehicle systems] Figure 10 is a configuration diagram of the optical device 1 (1a, 1b) and the in-vehicle system (driving assistance device) 1000 equipped therewith according to each embodiment. The in-vehicle system 1000 is held by a movable mobile body (mobile device) such as an automobile (vehicle) and is a system for assisting the driving (operation) of the vehicle based on distance information of objects such as obstacles and pedestrians around the vehicle acquired by the optical device 1. Figure 11 is a schematic diagram of a vehicle 500 as a mobile device including the in-vehicle system 1000. In Figure 11, the case in which the distance measurement range (detection range) of the optical device 1 is set to the front of the vehicle 500 is shown, but the distance measurement range may also be set to the rear or side of the vehicle 500.

[0066] As shown in Figure 10, the in-vehicle system 1000 comprises an optical device 1, a vehicle information acquisition device 200, a control device (control unit, ECU: electronic control unit) 300, and a warning device (warning unit) 400. In the in-vehicle system 1000, the overall control unit 140 provided in the distance measuring device 1 has the functions of a distance acquisition unit (acquisition unit) and a collision determination unit (determination unit). However, if necessary, the in-vehicle system 1000 may provide a distance acquisition unit and a collision determination unit separate from the overall control unit 140, and each may be provided outside the optical device 1 (for example, inside the vehicle 500). Alternatively, the control device 300 may be used as a control unit 60.

[0067] Figure 12 is a flowchart showing an example of the operation of the in-vehicle system 1000 according to this embodiment. The operation of the in-vehicle system 1000 will be described below in accordance with this flowchart.

[0068] First, in step S1, the light source unit 113 of the distance measuring device 1 illuminates the object around the vehicle, and the light receiving unit 121 receives reflected light from the object. Based on the signal output by the light receiving unit 121, the overall control unit 140 acquires distance information indicating the distance to the object. In step S2, the vehicle information acquisition device 200 acquires vehicle information, including the vehicle speed, yaw rate, and steering angle. Then, in step S3, the overall control unit 140 uses the distance information acquired in step S1 and the vehicle information acquired in step S2 to determine whether the distance to the object falls within a preset distance range.

[0069] This allows the system to determine whether or not an object exists within a set distance around the vehicle and to determine the possibility of a collision between the vehicle and the object. Steps S1 and S2 may be performed in the reverse order of the above, or they may be processed in parallel. The control unit 60 determines "possibility of collision" if an object exists within the set distance (step S4), and determines "no possibility of collision" if an object does not exist within the set distance (step S5).

[0070] Next, if the overall control unit 140 determines that there is a possibility of collision, it notifies (transmits) the determination result to the control device 300 and the warning device 400. At this time, the control device 300 controls the vehicle based on the determination result from the overall control unit 140 (step S6), and the warning device 400 issues a warning to the vehicle user (driver, passengers) based on the determination result from the control unit 60 (step S7). Note that notification of the determination result only needs to be made to at least one of the control device 300 and the warning device 400.

[0071] The control device 300 can control the movement of a vehicle by outputting control signals to the vehicle's drive unit (such as the engine or motor). For example, it can control the vehicle by applying the brakes, releasing the accelerator, turning the steering wheel, and generating control signals to apply braking force to each wheel, thereby suppressing the output of the engine or motor. The warning device 400 can also warn the user by, for example, emitting a warning sound, displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0072] As described above, the in-vehicle system 1000 according to this embodiment can detect objects and measure their distance through the above-described process, making it possible to avoid collisions between the vehicle and the objects. In particular, by applying the optical device 1 according to each of the embodiments described above to the in-vehicle system 1000, high distance measurement accuracy can be achieved, making it possible to detect objects and determine collisions with high accuracy.

[0073] In this embodiment, the in-vehicle system 1000 is applied to driver assistance (collision damage mitigation), but it is not limited to this, and the in-vehicle system 1000 may also be applied to cruise control (including with full-speed following function) or autonomous driving. Furthermore, the in-vehicle system 1000 is not limited to automobiles and other vehicles, but can be applied to mobile objects such as ships, aircraft, and industrial robots. Moreover, it is not limited to mobile objects, but can be applied to various devices that utilize object recognition, such as intelligent transportation systems (ITS) and surveillance systems.

[0074] Furthermore, the in-vehicle system 1000 and the vehicle (mobility device) 500 may be equipped with a notification device (notification unit) to notify the manufacturer of the in-vehicle system or the dealer of the mobility device if the vehicle 500 collides with an obstacle. For example, the notification device may be one that sends information regarding the collision between the vehicle 500 and the obstacle (collision information) to a pre-set external notification destination via email or the like.

[0075] In this way, by adopting a configuration in which collision information is automatically notified by the notification device, it is possible to promptly take action such as inspection and repair after a collision occurs. The recipients of the collision information may be insurance companies, medical institutions, the police, or any other recipients set by the user. Furthermore, the notification device may be configured to notify recipients not only of collision information, but also of malfunction information of various parts and information on the wear of consumables. The detection of whether or not a collision has occurred may be performed using distance information acquired based on the output from the light receiving unit 121 described above, or it may be performed by other detection units (sensors).

[0076] Each embodiment makes it possible to provide a compact and high-resolution optical device, an in-vehicle system, and a mobile device.

[0077] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. [Explanation of symbols]

[0078] 113 Light source unit 122 TDC Array Section 123 Signal Processing Unit 121 Light receiving part 130 Image-side telecentric lens 140 Overall Control Unit 150 Beam Splitter 160 refractive index material

Claims

1. A light source equipped with a light-emitting element, An optical element with microlenses arranged, An image-side telecentric lens that projects photons emitted by the light-emitting element onto a target, A light projection device characterized by having control means for controlling the optical path length between the microlens and the image-side telecentric lens.

2. The light projection device according to claim 1, wherein the control means has a refractive index element capable of controlling the refractive index in the optical path of the optical system formed by the light source, the optical element, and the image-side telecentric lens, and the optical path length is controlled by controlling the refractive index of the refractive index element.

3. The light projection device according to claim 2, characterized in that the control means controls the refractive index by configuring the refractive index element to be insertable and removable from the optical path.

4. The light projector according to claim 2, characterized in that the refractive index element is composed of liquid crystal ND.

5. It has a focus control unit that controls the focus of the image-side telecentric lens, The light projection device according to claim 1, characterized in that the control means controls the optical path length in accordance with the focus control performed by the image-side telecentric lens.

6. The light projection device according to claim 5, characterized in that the focus control unit controls the focus of the image-side telecentric lens based on the distance measurement result of the measuring means.

7. The light projection device according to claim 1, characterized in that the control means controls the optical path length according to the zoom of the image-side telecentric lens.

8. A light projection device according to any one of claims 1 to 7, A light receiving means equipped with a light receiving element that outputs a signal corresponding to the received light, A measuring means for measuring the distance to an object based on the signal output from the light-receiving element, A distance measuring device characterized by having the following features.

9. The optical path has a beam splitter, The distance measuring device according to claim 8, characterized in that the light source and the light receiving means share the image-side telecentric lens by the beam splitter.

10. An in-vehicle system comprising a distance measuring device as described in claim 8, characterized in that the possibility of collision between the vehicle and the object is determined based on the distance obtained by the distance measuring device.

11. The in-vehicle system according to claim 10, further comprising a control device that outputs a control signal for generating braking force on the vehicle when it is determined that there is a possibility of collision between the vehicle and the object.

12. The in-vehicle system according to claim 10, further comprising a warning device that warns the user of the vehicle when it is determined that there is a possibility of collision between the vehicle and the object.

13. A mobile device comprising the distance measuring device described in claim 8, characterized in that it is movable while holding the distance measuring device.

14. The mobile device according to claim 13, further comprising determination means for determining the possibility of collision with the target based on the distance obtained by the distance measuring device.

15. The moving device according to claim 13, further comprising control means that outputs a control signal to control movement when it is determined that there is a possibility of collision with the aforementioned object.

16. The mobile device according to claim 13, further comprising a warning device that warns the user of the mobile device when it is determined that there is a possibility of collision with the aforementioned object.

17. The mobile device according to claim 13, further comprising a notification means for notifying an external party of information relating to a collision with the aforementioned object.

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