JP2023068209A - Range finder and light emitting device - Google Patents

Abstract

To provide a ranging device and a light-emitting device, capable of irradiating an object with appropriate illumination light.SOLUTION: A ranging device is provided, comprising a light-emitting unit provided with multiple light-emitting elements for generating light and configured to irradiate an object with light form the light-emitting elements, a light reception unit for receiving the light reflected from the object, and a ranging unit configured to measure distance to the object based on the light received by the light reception unit, where the light-emitting unit irradiates the object with the light from the light-emitting elements by sequentially turning on the light-emitting elements one-by-one or in multiples.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to range finding devices and light emitting devices.

2. Description of the Related Art A range finding method is known that measures the distance to a subject by triangulation. An example of the distance measuring method is the light section method. In the light-section method, an object is imaged while being scanned with a sheet of laser light, and the distance to the object is calculated using an imaging signal obtained by the imaging. In this case, it is necessary to oscillate the laser beam by some means to irradiate the object with the oscillating laser beam. By vibrating the laser beam, it is possible to scan the subject with the laser beam.

JP 2017-187386 A International publication WO2019/053998

Therefore, it is conceivable to mount an actuator for vibrating the laser beam in the distance measuring device. In this case, the laser light can be vibrated by vibrating a mirror that reflects the laser light or a lens that shapes the laser light using an actuator.

However, when an actuator is mounted in the distance measuring device, there are problems such as an increase in the number of parts of the distance measuring device due to the actuator and a need for a small actuator in order to obtain highly accurate vibration. In this way, when measuring the distance to the subject by triangulation, the question arises as to what method is used to irradiate the subject with suitable light.

Accordingly, the present disclosure provides a distance measuring device and a light emitting device capable of irradiating a subject with suitable irradiation light.

A distance measuring device according to a first aspect of the present disclosure includes a plurality of light-emitting elements that generate light, a light-emitting device that irradiates a subject with light from the light-emitting elements, and a light-receiving device that receives light reflected from the subject. and a distance measuring unit for measuring the distance to the subject based on the light received by the light receiving device, wherein the light emitting device sequentially turns on the light emitting elements one by one or each of a plurality of the light emitting elements. and irradiates the subject with the light from the light emitting element. As a result, for example, it is possible to irradiate a subject with illumination light that is suitable for distance measurement without using parts such as small actuators. It becomes possible to

Moreover, this 1st side surface WHEREIN: The said light emitting element may be arrange|positioned at linear form. As a result, for example, by sequentially lighting the light emitting elements along the line, it is possible to irradiate the object with irradiation light that moves on the surface of the object.

Moreover, in this first aspect, the light emitting elements may be arranged in a two-dimensional array. As a result, for example, by sequentially turning on the light-emitting elements in the two-dimensional array, it is possible to irradiate the object with irradiation light that moves on the surface of the object.

Moreover, in this first aspect, the two-dimensional array of light emitting elements may include a plurality of line portions in which the light emitting elements are arranged in a line. As a result, for example, by sequentially turning on the light-emitting elements for each line portion, it is possible to irradiate the object with irradiation light that moves on the surface of the object.

Further, on the first side surface, the line portions extend in a first direction and are adjacent to each other in a second direction perpendicular to the first direction, and the two-dimensional array of the light emitting elements includes the The light emitting elements may be arranged in a zigzag arrangement so as not to be continuous in the second direction. As a result, for example, by narrowing the width between line portions, it is possible to increase the number of line portions.

In the first aspect, the light-emitting device may irradiate the object with light from the light-emitting elements by sequentially lighting the light-emitting elements for each line portion. This makes it possible, for example, to irradiate the object with irradiation light that moves on the surface of the object.

Further, in this first aspect, the light-emitting device includes a plurality of switches for driving the light-emitting elements, each switch being electrically connected to a plurality of light-emitting elements in a corresponding one line portion. may As a result, for example, it is possible to control the lighting of the light-emitting element for each line portion by turning on/off the corresponding switch.

Moreover, in this first aspect, the light emitting device may irradiate the subject with light including one or more line lights extending in a third direction. As a result, for example, distance measurement using line light can be realized.

Further, in this first aspect, the light emitting device irradiates the subject with light including the one or more line lights extending in the third direction and one or more line lights extending in the fourth direction. may As a result, for example, it is possible to realize distance measurement using light that spreads in a plurality of directions.

Further, in this first aspect, the light emitting device may irradiate the subject with light from the light emitting element by tilting the optical axis of the light emitting device with respect to the optical axis of the light receiving device. As a result, for example, it is possible to suppress the adverse effect of zero-order light on distance measurement.

In the first aspect, the light emitting device tilts the optical axis so that the zero-order light from the light emitting element is irradiated onto a region outside the light receiving range of the light receiving device. may This makes it possible, for example, to exclude the 0th order light from the imaging signal and suppress the adverse effect of the 0th order light on distance measurement.

Further, according to the first aspect, in the light emitting device, the light from the light emitting element includes a plurality of spots of 0th order light, and the plurality of spots are applied to a region within the light receiving range of the light receiving device. The object may be irradiated with light from the light-emitting element as in the above. As a result, for example, by suppressing the brightness of the 0th order light instead of tilting the optical axis of the light emitting device, it is possible to suppress the adverse effect of the 0th order light on distance measurement.

Moreover, in this first aspect, the timing of sequential lighting of the light-emitting elements and the timing of exposure in the light-receiving device may be synchronized. This makes it possible, for example, to reduce wasteful operations of the light-emitting device and the light-receiving device.

Moreover, in this first aspect, the light-emitting device may include a collimating lens that collimates light from the light-emitting element and irradiates the subject with the light. As a result, for example, the shape of light for distance measurement can be formed into a desired shape.

Moreover, in this first aspect, the light-emitting device may include a diffraction optical element that forms light from the light-emitting element by diffraction and irradiates the subject with the light. This makes it possible, for example, to diffract light for distance measurement in a desired manner.

Further, in this first aspect, the light receiving device includes an imaging section that captures an image of the light irradiated to the subject, and the distance measuring section measures the distance between the subject and the subject based on the light captured by the imaging section. may be measured. As a result, for example, distance measurement can be performed based on the processing of the imaging signal.

A light-emitting device according to a second aspect of the present disclosure includes a light source including a plurality of light-emitting elements that generate light, and an optical element that irradiates a subject with light from the light-emitting elements. Light from the light-emitting elements is applied to the subject by sequentially lighting each of the plurality of light-emitting elements. As a result, for example, it is possible to irradiate an object with irradiation light that moves on the surface of the object without using a component such as a small actuator.

Moreover, in this second aspect, the optical element may include a collimating lens that collimates the light from the light emitting element and illuminates the subject. This makes it possible, for example, to diffract the light with which the subject is irradiated in a desired manner.

Moreover, in this second aspect, the optical element may include a diffraction optical element that shapes the light from the light emitting element by diffraction and irradiates the subject with the light. This makes it possible, for example, to diffract the light with which the subject is irradiated in a desired manner.

Moreover, in this second aspect, the light reflected from the subject may be received by a light receiving device. This makes it possible to use, for example, suitable irradiation light emitted from the light-emitting device to the subject for distance measurement or the like.

1 is a block diagram showing the configuration of a distance measuring device according to a first embodiment; FIG. 4 is a perspective view showing the structure of the distance measuring device of the first embodiment; 1 is a longitudinal sectional view showing the structure of a light emitting device according to a first embodiment; FIG. It is a cross-sectional view showing the structure of the light receiving device of the first embodiment. 4 is another longitudinal sectional view showing the structure of the light emitting device of the first embodiment; FIG. FIG. 2 is a plan view showing an arrangement example of light emitting elements according to the first embodiment; FIG. 4 is a plan view showing an operation example of the light emitting device of the first embodiment; FIG. 3 is a plan view showing an example of connection of light emitting elements according to the first embodiment; It is a figure which shows the example of the pattern of irradiation light of 1st Embodiment. FIG. 4 is a cross-sectional view for explaining the action of the diffractive optical element of the first embodiment; FIG. 5 is another diagram showing an example of a pattern of irradiation light according to the first embodiment; 4 is a timing chart showing an operation example of the distance measuring device of the first embodiment; 7 is a timing chart showing another operation example of the distance measuring device of the first embodiment; It is a figure for demonstrating the range-finding system of the range finder of 1st Embodiment.

Embodiments of the present disclosure will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the distance measuring device of the first embodiment.

The distance measuring device of FIG. 1 includes a light emitting device 1, a light receiving device 2, and a distance measuring section 3. As shown in FIG. The light-emitting device 1 includes a plurality of light-emitting elements (described later) that generate light, and irradiates a subject P with light from these light-emitting elements. The light receiving device 2 receives the light reflected from the subject P. As shown in FIG. The distance measurement unit 3 measures (calculates) the distance to the subject P based on the light received by the light receiving device 2 . The distance measuring device in FIG. 1 is used, for example, to recognize gestures made by humans using their hands, but it may also be used for other uses (for example, recognition of human faces).

The light emitting device 1 includes a light source driver 11 , a light source 12 , a collimator lens 13 , and a diffractive optical element (DOE) 14 . Collimating lens 13 and diffractive optical element 14 are examples of optical elements of the present disclosure. The light receiving device 2 includes a lens unit 21 , an imaging section 22 and an imaging signal processing section 23 .

The light source driver 11 drives the light source 12 to generate light from the light source 12 . The light source 12 includes the plurality of light emitting elements described above. The light source driver 11 of this embodiment drives these light emitting elements to generate light from these light emitting elements. Each light-emitting element of this embodiment has, for example, a VCSEL (Vertical Cavity Surface Emitting Laser) structure, and generates laser light. The light emitted from the light source 12 is visible light or infrared light, for example. Examples of this infrared light are near infrared light (NIR) and short wavelength infrared light (SWIR).

The collimator lens 13 collimates the light from the light source 12 and emits it to the diffractive optical element 14 . Thereby, the light from the light source 12 is formed into parallel light. The diffractive optical element 14 shapes the light from the collimator lens 13 by diffraction and emits the light from the light emitting device 1 . As a result, after the light from the light source 12 is shaped into parallel light, the light is shaped into light having a desired pattern shape. The light emitting device 1 irradiates the subject P with light (irradiation light) having this desired pattern shape. The pattern projected onto the subject P is also called a projected image. The light irradiated to the subject P is reflected by the subject P and received by the light receiving device 2 .

The lens unit 21 includes a plurality of lenses (described later), and collects light reflected from the subject P by these lenses. The surfaces of these lenses are provided with an antireflection film that prevents reflection of light. The antireflection film may function as a BPF (bandpass filter) that transmits light having the same wavelength as the light emitted from the light source 12 .

The imaging unit 22 captures an image of the light condensed by the lens unit 21 and outputs an imaging signal obtained by imaging. The imaging unit 22 is, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

The imaging signal processing unit 23 performs predetermined signal processing on the imaging signal output from the imaging unit 22 . The imaging signal processing unit 23 performs predetermined image processing on the image captured by the imaging unit 22, for example. The imaging signal processing unit 23 outputs the imaging signal subjected to the above signal processing to the distance measuring unit 3 .

The distance measuring unit 3 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like for executing various information processing. The distance measuring unit 3 controls the operation of the light source driving unit 11 via, for example, a light source driver (not shown). Further, the distance measuring unit 3 measures the distance to the subject P based on the imaging signal of the light irradiated to the subject P, for example, based on the principle of triangulation. In this manner, the distance measuring section 3 controls various operations of the distance measuring apparatus of FIG.

FIG. 2 is a perspective view showing the structure of the distance measuring device of the first embodiment.

FIG. 2 shows X, Y, and Z axes that are perpendicular to each other. The X and Y directions correspond to the lateral direction (horizontal direction), and the Z direction corresponds to the longitudinal direction (vertical direction). The +Z direction corresponds to the upward direction, and the -Z direction corresponds to the downward direction. The -Z direction may or may not exactly match the direction of gravity.

FIG. 2 shows the diffractive optical element 14 provided in the light emitting device 1 and the lens unit 21 provided in the light receiving device 2. As shown in FIG. In FIG. 2, the lens unit 21 faces the Y direction, while the direction of the diffractive optical element 14 is tilted downward with respect to the Y direction.

FIG. 3 is a longitudinal sectional view showing the structure of the light emitting device 1 of the first embodiment.

FIG. 3 shows the light source 12, the collimating lens 13, the diffractive optical element 14, and the reflecting prism 15 provided in the light emitting device 1. FIG. In the light emitting device 1 of this embodiment, the light emitted from the light source 12 is reflected by the reflecting prism 15, passes through the collimating lens 13 and the diffraction optical element 14, and is irradiated onto the subject P.

FIG. 4 is a cross-sectional view showing the structure of the light receiving device 2 of the first embodiment.

FIG. 4 shows the lens unit 21 provided in the light receiving device 2 and the imaging section 22 . The lens unit 21 of this embodiment includes a plurality of (here, two) lenses 21a and 21b. The lens unit 21 converges the light reflected from the subject P with these lenses 21a and 21b.

3 and 4 show the optical axis A1 of the light emitting device 1 and the optical axis A2 of the light receiving device 2. FIG. The optical axis A1 of the light emitting device 1 passes through the centers of the diffractive optical element 14 and the collimator lens 13, and the optical axis A2 of the light receiving device 2 passes through the centers of the lenses 21a and 21b. In FIG. 3, the optical axis A1 of the light emitting device 1 is tilted with respect to the Y direction, and the orientation of the diffractive optical element 14 is tilted downward with respect to the Y direction (see also FIG. 2). In FIG. 4, the optical axis A2 of the light receiving device 2 is parallel to the Y direction, and the lens unit 21 faces the Y direction (see also FIG. 2). Therefore, the optical axis A1 of the light emitting device 1 is tilted with respect to the optical axis A2 of the light receiving device 2 .

For example, the distance measuring device of the present embodiment may be configured such that the optical axis A1 of the light emitting device 1 can be tilted with respect to the optical axis A2 of the light receiving device 2 by driving the light emitting device 1 . In this case, the light emitting device 1 irradiates the subject P with light from the light source 12 with the optical axis A1 of the light emitting device 1 tilted with respect to the optical axis A2 of the light receiving device 2 . This makes it possible to irradiate the area outside the light receiving range of the light receiving device 2 with the 0th order light contained in the light from the light source 12, and it is possible to suppress the adverse effect of the 0th order light on distance measurement. The details of such control of the optical axis A1 will be described later.

FIG. 5 is another longitudinal sectional view showing the structure of the light emitting device 1 of the first embodiment.

FIG. 5 shows the light source drive section 11 and the light source 12 provided in the light emitting device 1 . As shown in FIG. 5 , the light source 12 includes a substrate 31 , a laminated film 32 , a plurality of light emitting elements 33 , a plurality of anode electrodes 34 and a plurality of cathode electrodes 35 . Also, the light source driving section 11 includes a substrate 41 and a plurality of connection pads 42 . The light source 12 of this embodiment is a semiconductor chip including a substrate 31 and is mounted on the light source driving section 11 including the substrate 41 via a plurality of bumps 16 .

FIG. 5 shows X', Y', and Z' axes which are perpendicular to each other. The X' and Y' directions correspond to the lateral direction (horizontal direction) when the substrate 31 is horizontally arranged, and the Z' direction corresponds to the vertical direction (vertical direction) when the substrate 31 is horizontally arranged. do. The +Z' direction and the -Z' direction respectively correspond to the upward direction and the downward direction when the substrate 31 is arranged horizontally. As can be seen from the tilt of the light source 12 shown in FIG. 3, the X', Y', and Z' directions generally do not coincide with the X, Y, and Z directions.

The details of the structures of the light source driver 11 and the light source 12 will be described below with reference to FIG. In the description of FIG. 5, the structures of the light source driving section 11 and the light source 12 will be described with the +Z′ direction and the −Z′ direction as the upward direction and the downward direction, respectively.

The substrate 31 is, for example, a semiconductor substrate such as a GaAs (gallium arsenide) substrate. FIG. 5 shows the front surface S1 of the substrate 31 facing the -Z' direction and the back surface S2 of the substrate 31 facing the +Z' direction.

Laminated film 32 includes a plurality of layers laminated on surface S<b>1 of substrate 31 . Examples of these layers are n-type semiconductor layers, active layers, p-type semiconductor layers, light reflecting layers, insulating layers with light exit windows, and the like. The laminated film 32 includes a plurality of mesa portions M projecting in the -Z' direction. A part of these mesa portions M are a plurality of light emitting elements 33 .

The plurality of light emitting elements 33 are provided on the surface S1 side of the substrate 31 as part of the laminated film 32 . Each light emitting element 33 of this embodiment has a VCSEL structure and emits light in the +Z' direction. Light emitted from each light emitting element 33 passes through the substrate 31 from the surface S1 to the rear surface S2 and is emitted from the rear surface S2 of the substrate 31 . Thus, the light source 12 of this embodiment is a back-illuminated VCSEL chip.

The anode electrode 34 is formed on the bottom surface of the light emitting element 33 . The cathode electrode 35 is formed on the lower surface of the mesa portion M other than the light emitting element 33 and extends to the lower surface of the laminated film 32 between the mesa portions M. As shown in FIG. Each light emitting element 33 emits light when a current flows between its anode electrode 34 and corresponding cathode electrode 35 .

As described above, the light source 12 is arranged on the light source driving section 11 via the bumps 16 and electrically connected to the light source driving section 11 by the bumps 16 . Specifically, a connection pad 42 is formed on a substrate 41 included in the light source driving section 11 , and a mesa section M is arranged on the connection pad 42 via the bump 16 . Each mesa portion M is arranged on the bump 16 via the anode electrode 34 or the cathode electrode 35 . The substrate 41 is, for example, a semiconductor substrate such as a Si (silicon) substrate.

The light source drive section 11 includes a drive circuit that drives the light source 12 . FIG. 5 schematically shows a plurality of switches SW included in this drive circuit. Each switch SW is electrically connected to the corresponding light emitting element 33 via the bump 16 . The light source driver 11 of the present embodiment can control (turn on/off) these switches SW individually. Therefore, the light source driving section 11 can drive the plurality of light emitting elements 33 individually. This makes it possible to precisely control the light emitted from the light source 12, for example, by causing only the light emitting element 33 required for distance measurement to emit light. Such individual control of the light emitting elements 33 is realized by arranging the light source driving section 11 below the light source 12 to facilitate electrical connection between each light emitting element 33 and the corresponding switch SW. It is possible. A modified example of such a switch SW will be described later.

FIG. 6 is a plan view showing an arrangement example of the light emitting elements 33 of the first embodiment.

In the example of A of FIG. 6, a plurality of light emitting elements 33 are arranged in a line (one-dimensional array) on the surface S1 of the substrate 31 . Specifically, these light emitting elements 33 are arranged at equal intervals in the X' direction. Although FIG. 6A shows five light emitting elements 33 as an example, the number of light emitting elements 33 arranged in a line on the substrate 31 may be other than five. Note that these light emitting elements 33 may be arranged in a direction other than the X' direction, or may be arranged at non-equidistant intervals. An example of such arrangement will be described later.

In the example of B of FIG. 6 as well, a plurality of light emitting elements 33 are arranged in a line (one-dimensional array) on the surface S1 of the substrate 31 . However, these light emitting elements 33 are arranged at equal intervals in the Y' direction. In this manner, the light emitting elements 33 of this embodiment can be arranged in a line in various manners.

In the example of FIG. 6C, a plurality of light emitting elements 33 are arranged in a regular two-dimensional array on the surface S1 of the substrate 31 . Specifically, these light emitting elements 33 are arranged at equal intervals in the X' direction and the Y' direction, and are arranged in a square lattice. Although FIG. 6C shows twenty-five light-emitting elements 33 as an example, the number of light-emitting elements 33 arranged in a two-dimensional array on the substrate 31 may be other than twenty-five. These light emitting elements 33 may be arranged in a regular two-dimensional array in an arrangement other than a square lattice, or may be arranged in an irregular two-dimensional array. An example of such arrangement will be described later.

A plurality of light emitting elements 33 shown in FIG. 6C includes a plurality of line portions L1, here 25 light emitting elements 33 include 5 line portions L1. In each line portion L1, a plurality of (here, five) light emitting elements 33 are arranged in a line. These line portions L1 extend in the Y' direction and are adjacent to each other in the X' direction. Details of such a line portion L1 will be described later with reference to FIG. 6E.

From another point of view, the plurality (25) of light emitting elements 33 shown in FIG. 6C includes a plurality (5) of line portions L2. In each line portion L2, a plurality of (five) light emitting elements 33 are arranged in a line. These line portions L2 extend in the X' direction and are adjacent to each other in the Y' direction. Details of such a line portion L2 will be described later with reference to FIG. 6F.

In the example of FIG. 6D, a plurality of light emitting elements 33 are arranged on the surface S1 of the substrate 31 in an irregular two-dimensional array. Thus, the light-emitting elements 33 of this embodiment can be arranged in a two-dimensional array in various ways.

In the example of FIG. 6E, a plurality of light emitting elements 33 are arranged on the surface S1 of the substrate 31 in a regular two-dimensional array. These light emitting elements 33 include a plurality of line portions L1 extending in the Y' direction, as in the example of C of FIG. However, these light emitting elements 33 are arranged in a zigzag arrangement so that the light emitting elements 33 are not continuous in the X' direction. For example, in FIG. 6C, the light emitting element 33 of a certain line portion L1 and the light emitting element 33 of the adjacent line portion L1 are arranged (continuously) in the X′ direction, but in FIG. , the light emitting element 33 of a certain line portion L1 and the light emitting element 33 of the adjacent line portion L1 are not arranged in the X′ direction (not continuous). That is, in E of FIG. 6, the position of the light emitting element 33 in the Y' direction is shifted between a certain line portion L1 and the adjacent line portion L1. In FIG. 6E, the Y' direction is an example of the first direction of the present disclosure, and the X' direction is an example of the second direction of the present disclosure.

In the example of FIG. 6F, a plurality of light emitting elements 33 are arranged on the surface S1 of the substrate 31 in a regular two-dimensional array. These light emitting elements 33 include a plurality of line portions L2 extending in the X' direction, similar to the example of C in FIG. However, these light emitting elements 33 are arranged in a zigzag arrangement so that the light emitting elements 33 are not continuous in the Y' direction. For example, in FIG. 6C, the light emitting element 33 of a certain line portion L2 and the light emitting element 33 of the adjacent line portion L2 are arranged (continuously) in the Y′ direction, but in FIG. , the light emitting element 33 of a certain line portion L2 and the light emitting element 33 of the adjacent line portion L2 are not arranged in the Y′ direction (not continuous). In other words, in FIG. 6F, the position of the light emitting element 33 in the X' direction is shifted between a certain line portion L2 and the adjacent line portion L2. In FIG. 6F, the X' direction is an example of the first direction of the present disclosure, and the Y' direction is an example of the second direction of the present disclosure.

In this embodiment, the subject P is irradiated with the light from these light emitting elements 33 by sequentially turning on the plurality of light emitting elements 33 provided on the substrate 31 one by one or by a plurality of them. For example, when adopting the arrangement example shown in A of FIG. The individual light-emitting elements 33 may be lit in five stages. In this case, the light emitting elements 33 are lit one by one. On the other hand, when adopting the arrangement example shown in FIG. 6C, the light emitting elements 33 in the first, second, third, fourth, and fifth line portions L1 from the left in FIG. 6C are sequentially turned on. The 25 light-emitting elements 33 may be lighted in 5 steps. In this case, a plurality of light emitting elements 33 (five in this case) are turned on.

According to the present embodiment, it is possible to irradiate the subject P with the irradiation light that moves on the surface of the subject P by sequentially lighting the plurality of light emitting elements 33 one by one or a plurality of the light emitting elements 33 . That is, it becomes possible to scan the subject P with the irradiation light. This makes it possible to realize distance measurement by the light section method.

In order to scan the object P with the irradiation light, it is conceivable to mount an actuator for vibrating the irradiation light in the distance measuring device. However, when an actuator is mounted in the distance measuring device, there are problems such as an increase in the number of parts of the distance measuring device due to the actuator and a need for a small actuator in order to obtain highly accurate vibration. According to the present embodiment, the irradiation light can be moved without using an actuator, so it is possible to suppress an increase in the number of parts of the distance measuring device. In addition, according to the present embodiment, since the irradiation light can be moved by moving the lighting position of the light emitting element 33, the movement of the irradiation light can be performed with precision rather than mechanical means (such as an actuator) with low accuracy. can be controlled by an optical means (light-emitting element 33) having a high power. Furthermore, no electric power is required to operate the actuator. This makes it possible to realize the movement of the irradiation light at low cost and with high precision. Thus, according to the present embodiment, it is possible to irradiate the subject P with suitable irradiation light.

The light emitting elements 33 of this embodiment are preferably arranged in a staggered arrangement as shown in E (or F) of FIG. 6 rather than in a square lattice as shown in C of FIG. This makes it possible to arrange the light emitting elements 33 at a high density. In FIG. 6C, 25 light emitting elements 33 are arranged on the substrate 31, whereas in FIG. 6E (or F), 45 light emitting elements 33 are arranged on the substrate 31. Please note. Arranging the light-emitting elements 33 at a high density has the advantage that, for example, the accuracy of scanning the subject P with the irradiation light can be improved.

FIG. 7 is a plan view showing an operation example of the light emitting element 33 of the first embodiment.

7A to 7E, a plurality of light emitting elements 33 are arranged in a zigzag pattern including a plurality of line portions L1, similar to the example of FIG. 6E. FIGS. 7A to 7E show how these light emitting elements 33 are sequentially lit for each line portion L1. Specifically, A to E of FIG. 7 show how the light emitting elements 33 in the first, second, third, fourth, and fifth line portions L1 from the left are lit. Reference numeral 33a indicates the light-emitting element 33 during lighting. In this example, the light emitting elements 33 in the first, second, third, fourth, and fifth line portions L1 from the left are sequentially turned on, so that the subject P is irradiated with the light from these light emitting elements 33. . In this example, after that, the light-emitting elements 33 in the sixth, seventh, eighth, and ninth line portions L1 from the left may be sequentially turned on.

According to this example, it is possible to irradiate the object P with irradiation light that moves on the surface of the object P by sequentially lighting the plurality of light emitting elements 33 for each line portion L1. That is, it becomes possible to scan the subject P with the irradiation light. This makes it possible to realize distance measurement by the light section method.

In this example, the number of line portions L1 is increased from five to nine by adopting a staggered arrangement instead of a square lattice. When the number of line portions L1 is five, the irradiation position of the irradiation light can be changed in five steps. On the other hand, when the number of line portions L1 is nine, the irradiation position of the irradiation light can be changed in nine steps. Therefore, according to this example, by adopting the staggered arrangement instead of the square lattice, it is possible to improve the accuracy of scanning the subject P with the irradiation light.

FIG. 8 is a plan view showing a connection example of the light emitting element 33 of the first embodiment.

When the operation examples of A to E in FIG. 7 are adopted, the switch SW of this embodiment may be connected to the light emitting element 33 as shown in FIG. Each switch SW in FIG. 8 is electrically connected to a plurality of (five) light emitting elements 33 in one corresponding line portion L1. Reference character E denotes wiring that connects each switch SW and these light emitting elements 33 . FIG. 8 shows six switches SW connected to six line segments L1.

According to this example, by controlling the ON/OFF of one switch SW, it is possible to control the ON/OFF of all the light emitting elements 33 in one line portion L1. This makes it possible to reduce the number of switches SW and to simplify the control of the light emitting elements 33 for each line portion L1.

FIG. 9 is a diagram showing an example of a pattern of irradiation light 51 according to the first embodiment.

Light from the light source 12 of this embodiment is shaped into parallel light by the collimating lens 13 , shaped into desired pattern light by the diffractive optical element 14 , and emitted from the light emitting device 1 . The light emitting device 1 irradiates the subject P with light (irradiation light 51) having this desired pattern shape. 9A to 9F show various examples of patterns of illumination light 51. FIG. For the X direction, Y direction, and Z direction, see FIG. 2 and the like.

In the example of A of FIG. 9, the irradiation light 51 includes a plurality of (here, three) line lights 52 extending in the Z direction. In this case, the light emitting device 1 preferably moves the irradiation position of the irradiation light 51 in the X direction. For example, when adopting the arrangement example shown in E of FIG. 6 and the operation examples shown in A to E of FIG. It is desirable to configure the light emitting device 1 so that the irradiation position of the irradiation light 51 moves in the X direction. This makes it possible to scan the subject P with the irradiation light 51 . In FIG. 9A, the Z direction is an example of the third direction of the present disclosure.

In the example of B of FIG. 9, the irradiation light 51 includes a plurality of (here, three) line lights 52 extending in the X direction. In this case, the light emitting device 1 preferably moves the irradiation position of the irradiation light 51 in the Z direction. For example, when adopting the arrangement example shown in E of FIG. 6 and the operation examples shown in A to E of FIG. It is desirable to configure the light emitting device 1 so that the irradiation position of the irradiation light 51 moves in the Z direction. This makes it possible to scan the subject P with the irradiation light 51 . In FIG. 9B, the X direction is an example of the third direction of the present disclosure.

In the example of C of FIG. 9, the irradiation light 51 includes a plurality of line lights 52 extending in the Z direction and a plurality of line lights 52 extending in the X direction, and has a grid-like shape. In this case, the irradiation position of the irradiation light 51 may be moved in the X direction or in the Z direction. In FIG. 9C, one of the Z direction and the X direction is an example of the third direction of the present disclosure, and the other of the Z direction and the X direction is an example of the fourth direction of the present disclosure.

In the example of D of FIG. 9, the irradiation light 51 includes a plurality of line lights 52 extending in the X direction, as in the example of B of FIG. In the example of E in FIG. 9, the illumination light 51 includes a plurality of line lights 52 extending in the Z direction, as in the example of A in FIG. In the example of FIG. 9F, the irradiation light 51 includes one line light 52 extending in the Z direction and one line light 52 extending in the X direction, and has a cross shape. In this manner, any number of line lights 52 may be included in the irradiation light 51 .

According to this embodiment, the collimating lens 13 and the diffractive optical element 14 can shape the light from the light source 12 into various shapes. For example, when light including one dot light or one line light is generated from the light source 12, the light from the light source 12 can be shaped into light having a two-dimensional spread. Irradiation light 51 shown in FIGS. 9A to 9F spreads in both the Z direction and the X direction.

The irradiation light 51 indicated by A to F in FIG. 9 includes linear light, but may also include non-linear light. For example, the irradiation light 51 may include curved light or randomly shaped light.

FIG. 10 is a cross-sectional view for explaining the action of the diffractive optical element 14 of the first embodiment.

Let φ be the angle of incidence of light incident on the diffractive optical element 14, and θ be the angle of diffraction of the diffracted light from the diffractive optical element 14. Equation (1) holds between φ and θ.

D×(sin φ−sin θ)=mλ (1)
Here, D represents the aperture interval of the diffractive optical element 14, λ represents the wavelengths of incident light and diffracted light, and m represents the diffraction order (integer value).

Here, when incident light enters the diffractive optical element 14 perpendicularly, φ=0° and sin φ=0. Furthermore, when the diffraction angle is small, sin θ≈θ. Substituting these results into equation (1) yields equation (2).

θ≈−mλ/D (2)
FIG. 10 shows 0th-order light, ±1st-order light, and ±2nd-order light included in diffracted light when the diffraction angle θ is represented by Equation (2). In this case, the zero-order light appears in the normal direction of the diffractive optical element 14 . Since the 0th-order light has a high luminance, it may cause erroneous recognition during distance measurement.

FIG. 11 is another diagram showing an example of the pattern of the irradiation light 51 of the first embodiment.

FIG. 11A shows irradiation light 51 including a plurality of line lights 52 extending in the Z direction, as in the example of FIG. 9E. FIG. 11A further shows a spot of 0th order light 53 included in the irradiation light 51 and a light receiving range (imaging range) 54 of the light receiving device 2 . The light-receiving device 2 of the present embodiment can receive the irradiation light 51 with which the region within the light-receiving range 54 is irradiated, and can take an image of the irradiation light 51 .

In A of FIG. 11 , a spot of 0th-order light 53 exists within the light receiving range 54 . Therefore, the 0th order light 53 is imaged by the light receiving device 2 . Since the brightness of the 0th-order light 53 is high, if the 0th-order light 53 is imaged by the light receiving device 2, it may cause erroneous recognition during distance measurement. Therefore, in this embodiment, either the first method shown in FIG. 11B or the second method shown in FIG. desirable.

In the first method (B in FIG. 11), the optical axis A1 of the light emitting device 1 is tilted with respect to the optical axis A2 of the light receiving device 2, as described with reference to FIGS. This makes it possible to irradiate the zero-order light 53 onto a region outside the light receiving range 54 as shown in FIG. 11B. In B of FIG. 11 , the spot of the zero-order light 53 exists outside the light receiving range 54 . This makes it possible to suppress the adverse effect of the zero-order light 53 on distance measurement.

In the second method (C in FIG. 11), the plurality of light emitting elements 33 provided on the substrate 31 are sequentially turned on. For example, these light emitting elements 33 are sequentially lit for each line portion L1 (see A to E in FIG. 7). In this case, five light-emitting elements 33 are lit at the same time.

C of FIG. 11 shows a state in which five light emitting elements 33 are lit at the same time. In this case, the illumination light 51 will contain five spots of zero-order light 53 . C of FIG. 11 shows five spots of 0th order light 53 existing within the light receiving range 54 .

When increasing the number of simultaneously lit light emitting elements 33 from one to five, if the power supplied to each light emitting element 33 is constant, the intensity of the irradiation light 51 is considered to increase five times. However, if the distance measurement can be sufficiently performed by lighting one light emitting element 33, it is useless to increase the intensity of the irradiation light 51 by a factor of five.

Therefore, when increasing the number of light-emitting elements 33 that are lit at the same time from one to five, the power supplied to each light-emitting element 33 may be reduced. may be reduced to 1. In this case, the total power supplied to the five light emitting elements 33 that are lit simultaneously is the same as the power that is supplied to the single light emitting element 33 that is lit alone. As a result, even if the number of simultaneously lit light emitting elements 33 is increased from one to five, the intensity of the irradiation light 51 is considered to be the same as before the increase in the number. This makes it possible to reduce the waste of increasing the intensity of the irradiation light 51 .

In this case, it is considered that the brightness of each spot of the zero-order light 53 is also reduced by reducing the power supplied to each light emitting element 33 to one-fifth. Therefore, if the brightness of each spot of the 0th order light 53 can be sufficiently reduced, even if the area within the light receiving range 54 is irradiated with the 0th order light 53, the adverse effect of the 0th order light 53 on distance measurement can be suppressed. can be done.

Therefore, in the second method (C in FIG. 11), the plurality of light emitting elements 33 provided on the substrate 31 are sequentially turned on, and the power supplied to each light emitting element 33 is set to be small. For example, the light-emitting elements 33 are sequentially turned on every five, and the power supplied to each light-emitting element 33 is set to 1/5 of the power for lighting one light-emitting element 33 alone. . As a result, even if the area within the light receiving range 54 is irradiated with the 0th order light 53, it is possible to suppress the adverse effect of the 0th order light 53 on distance measurement.

FIG. 12 is a timing chart showing an operation example of the distance measuring device of the first embodiment.

FIG. 12 shows the ON/OFF timing of the frame synchronization signal, the exposure timing of the imaging unit 22 (global shutter), the lighting timing of the light emitting element 33 (driver output), and the light emitting position of the light emitting element 33 (lighting position). ).

The frame synchronization signal of this embodiment employs negative logic. Therefore, when the frame synchronization signal falls once, one cycle of operation of the distance measuring device is started. FIG. 12 shows operations from the Nth cycle to the N+Mth cycle (N and M are integers equal to or greater than 1).

The imaging unit 22 of this embodiment includes a plurality of pixels arranged in a two-dimensional array. The timing of exposure shown in FIG. 12 indicates the timing of exposing these pixels with the light from the lens unit 21, that is, the timing of opening the shutter.

FIG. 12 shows M circles per cycle. The M circles represent the M light emitting elements 33 when the light emitting elements 33 are lit one by one, or the M line portions when the light emitting elements 33 are lit for each line portion. there is A black dot in each cycle indicates the light-emitting element 33 or line portion during lighting.

The light source 12 of this embodiment sequentially lights the light emitting elements 33 for each light emitting element 33 or for each line portion. The lighting timing shown in FIG. 12 indicates the timing of sequentially lighting the light emitting elements 33 for each light emitting element 33 or for each line portion.

FIG. 12 shows an operation example of the global shutter method. In this case, the distance measuring device synchronizes the timing of the sequential lighting of the light emitting elements 33 and the timing of the exposure in the imaging section 22, as shown in FIG. Therefore, when one or a plurality of light emitting elements 33 are lit once, each pixel of the imaging section 22 is exposed once in synchronization with the lighting. This makes it possible to reduce wasteful operation of the rangefinder. For example, it is possible to reduce unnecessary lighting of the light emitting element 33 and unnecessary exposure of the imaging unit 22, and it is possible to reduce the power consumption of the distance measuring device. Note that control for synchronizing lighting and exposure is performed by the distance measuring unit 3, for example.

FIG. 13 is a timing chart showing another operation example of the distance measuring device of the first embodiment.

FIG. 13 shows the ON/OFF timing of the frame synchronization signal, the exposure timing of the imaging unit 22, and the lighting timing (driver output) of the light emitting element 33. FIG. The properties of the frame synchronization signal and the lighting mode of the light emitting element 33 in the example of FIG. 13 are the same as in the example of FIG.

The imaging unit 22 of this embodiment includes a plurality of pixels arranged in a two-dimensional array as described above. For example, the imaging unit 22 of the present embodiment includes m rows and n columns of pixels (m and n are integers of 2 or more).

FIG. 13 shows an operation example of the rolling shutter method. In this case, the distance measuring device changes the timing of exposing the pixels of m rows and n columns, that is, the timing of opening the shutter for each row of pixels (n pixels). The two parallelograms shown in FIG. 13 show how the exposure timing changes from row to row. These parallelograms indicate the timings at which these pixels are exposed.

On the other hand, the rectangles within each parallelogram indicate the timings at which these pixels are exposed and the light-emitting elements 33 are lit. In other words, the rectangles in each parallelogram show the timings at which these pixels are exposed to the reflected light from the light source 12 and the reflected light from the external light, and the other The regions indicate the timings when these pixels are exposed only with the reflected light of the external light.

When the operation example of FIG. 13 is adopted, at the timing of the rectangle, these pixels are exposed with the reflected light from the light source 12 and the reflected light of the external light, and at the timing of the rectangle, A cycle may be provided in which these pixels are exposed only with reflected light of external light. In this case, by taking the difference between the imaging signal of the former cycle and the imaging signal of the latter cycle, it is possible to remove the influence of external light from the imaging signal of the former cycle.

FIG. 14 is a diagram for explaining the distance measurement method of the distance measurement device of the first embodiment.

FIG. 14 shows a triangle between the position of the subject (target) P, the position of the lens 21a, and the position of the light source 12 (more precisely, the position of the diffractive optical element 14). The triangulation of this embodiment is applied to this triangle.

FIG. 14 further shows the coordinates (x _P , y _P , z _P ) of the subject P, the coordinates (x _L , y _L , z _L ) of the sensor center of the imaging unit (sensor) 22, and the imaging unit 22. The coordinates of the point (x ₁ , y ₁ , z ₁ ) are shown. The x-axis of this embodiment is set to be parallel to the straight line (base line) connecting the position of the lens 21a and the position of the light source 12, and the xz plane of this embodiment is parallel to the triangle. is set to The x-, y-, and z-axes of this embodiment are perpendicular to each other.

FIG. 14 also shows the angle α of the triangle at the position of the lens 21a, the angle β of the triangle at the position of the light source 12, and the baseline length d. The length d of the baseline corresponds to the length of the base of the triangle. FIG. 14 further shows the distance _d1 in the x direction between the lens 21a and the subject P and the distance _d2 in the x direction between the light source 12 and the subject P. FIG.

In this case, since the relationships d=d ₁ +d ₂ , tan α=z _p /d ₁ , and tan β=z _p /d ₂ are established, d is represented by the following equation (3).
d= _zp /tanα+ _zp /tanβ (3)
By transforming the equation (3), _zp is expressed by the following equation (4).
z _P =d·tanα·tanβ/(tanα+tanβ) (4)
Here, assuming that the focal length of the lenses 21a and 21b of the lens unit 21 is f, the above tan α is expressed by the following equation (5).
tanα=f/x ₁ (5)
Substituting equation (5) into equation (4) yields the following equation (6).
z _P =d·f·tan β/(f+x ₁ ·tan β) (6)
In equation (6), the values of d, f, and β are known. Therefore, the value of _zp can be calculated by detecting the value of _x1 from the imaging signal. The value of _zp corresponds to the distance between the object P and the rangefinder.

As described above, the light-emitting device 1 of the present embodiment sequentially turns on the light-emitting elements 33 provided on the substrate 31 one by one or a plurality of the light-emitting elements 33, so that the light from these light-emitting elements 33 is projected onto the subject P. Irradiate. Therefore, according to the present embodiment, it is possible to irradiate the subject P with the irradiation light 51 suitable for distance measurement without using a component such as a small actuator. It becomes possible to irradiate the subject P with the light 51 .

Although the light-emitting device 1 and the light-receiving device 2 of this embodiment are provided in the same device (distance measuring device), they do not have to be provided in the same device. For example, a distance measuring system in which the light emitting device 1, the light receiving device 2, and the distance measuring section 3 are connected via a network may be constructed. In this case, transmission and reception of signals between the light emitting device 1, the light receiving device 2, and the distance measuring section 3 are performed by communication via a network. This network may be a wired network or a wireless network.

Although the embodiments of the present disclosure have been described above, these embodiments may be implemented with various modifications without departing from the gist of the present disclosure. For example, two or more embodiments may be combined and implemented.

In addition, this disclosure can also take the following configurations.

(1)
a light-emitting device that includes a plurality of light-emitting elements that generate light and irradiates a subject with light from the light-emitting elements;
a light receiving device that receives light reflected from the subject;
a distance measuring unit that measures the distance to the subject based on the light received by the light receiving device;
The light-emitting device is a distance measuring device that irradiates the subject with light from the light-emitting elements by sequentially turning on the light-emitting elements one by one or by a plurality of the light-emitting elements.

(2)
The distance measuring device according to (1), wherein the light emitting elements are arranged in a line.

(3)
The distance measuring device according to (1), wherein the light emitting elements are arranged in a two-dimensional array.

(4)
The distance measuring device according to (3), wherein the two-dimensional array of light emitting elements includes a plurality of line portions in which the light emitting elements are arranged in a line.

(5)
the line portions extend in a first direction and are adjacent to each other in a second direction perpendicular to the first direction;
The distance measuring device according to (4), wherein the two-dimensional array of light emitting elements is arranged in a zigzag arrangement so that the light emitting elements are not continuous in the second direction.

(6)
The distance measuring device according to (4), wherein the light emitting device irradiates the subject with light from the light emitting elements by sequentially lighting the light emitting elements line by line.

(7)
The light emitting device comprises a plurality of switches for driving the light emitting elements,
The range finder according to (4), wherein each switch is electrically connected to a plurality of light emitting elements within a corresponding one line segment.

(8)
The distance measuring device according to (1), wherein the light emitting device irradiates the subject with light including one or more line lights extending in a third direction.

(9)
The distance measurement according to (8), wherein the light emitting device irradiates the subject with light including the one or more line lights extending in the third direction and one or more line lights extending in the fourth direction. Device.

(10)
The distance measuring device according to (1), wherein the light emitting device tilts an optical axis of the light emitting device with respect to an optical axis of the light receiving device, and irradiates the subject with light from the light emitting element.

(11)
The distance measurement according to (10), wherein the light emitting device tilts its optical axis so that the zero-order light from the light emitting element is irradiated onto a region outside the light receiving range of the light receiving device. Device.

(12)
The light emitting device emits light from the light emitting element such that the light from the light emitting element includes a plurality of spots of zero-order light, and the plurality of spots are irradiated to an area within a light receiving range of the light receiving device. The distance measuring device according to (1), which irradiates the subject with light.

(13)
The distance measuring device according to (1), wherein the timing of sequential lighting of the light emitting elements and the timing of exposure in the light receiving device are synchronized.

(14)
The distance measuring device according to (1), wherein the light emitting device includes a collimating lens that collimates light from the light emitting element and irradiates the subject with the collimated light.

(15)
The distance measuring device according to (1), wherein the light emitting device includes a diffractive optical element that forms light from the light emitting element by diffraction and irradiates the subject with the light.

(16)
The light receiving device includes an imaging unit that captures the light irradiated to the subject,
The distance measuring device according to (1), wherein the distance measuring section measures the distance to the subject based on the light imaged by the imaging section.

(17)
a light source including a plurality of light emitting elements that generate light;
and an optical element that irradiates a subject with light from the light emitting element,
A light-emitting device that irradiates the subject with light from the light-emitting elements by sequentially turning on the light-emitting elements one by one or each of a plurality of the light-emitting elements.

(18)
The light emitting device according to (17), wherein the optical element includes a collimating lens for collimating light from the light emitting element and irradiating the subject with the collimated light.

(19)
The light-emitting device according to (17), wherein the optical element includes a diffractive optical element that forms light from the light-emitting element by diffraction and irradiates the subject with the light.

(20)
The light-emitting device according to (17), wherein the light reflected from the subject is received by a light-receiving device.

1: light-emitting device, 2: light-receiving device, 3: rangefinder,
11: light source driver, 12: light source, 13: collimator lens,
14: diffractive optical element, 15: reflecting prism, 16: bump,
21: lens unit, 21a: lens, 21b: lens,
22: imaging unit, 23: imaging signal processing unit,
31: substrate, 32: laminated film, 33: light emitting element, 33a: light emitting element during lighting,
34: anode electrode, 35: cathode electrode, 41: substrate, 42: connection pad,
51: irradiation light, 52: line light, 53: zero-order light, 54: light receiving range

Claims (20)

a light-emitting device that includes a plurality of light-emitting elements that generate light and irradiates a subject with light from the light-emitting elements;
a light receiving device that receives light reflected from the subject;
a distance measuring unit that measures the distance to the subject based on the light received by the light receiving device;
The light-emitting device is a distance measuring device that irradiates the subject with light from the light-emitting elements by sequentially turning on the light-emitting elements one by one or by a plurality of the light-emitting elements. 2. The rangefinder according to claim 1, wherein said light emitting elements are arranged in a line. 2. The distance measuring device according to claim 1, wherein said light emitting elements are arranged in a two-dimensional array. 4. The distance measuring device according to claim 3, wherein said two-dimensional array of said light emitting elements includes a plurality of line portions in which said light emitting elements are arranged in a line. the line portions extend in a first direction and are adjacent to each other in a second direction perpendicular to the first direction;
5. The distance measuring device according to claim 4, wherein said two-dimensional array of said light emitting elements is arranged in a zigzag arrangement so that said light emitting elements are not continuous in said second direction. 5. The distance measuring apparatus according to claim 4, wherein the light emitting device irradiates the subject with light from the light emitting elements by sequentially lighting the light emitting elements for each line portion. The light emitting device comprises a plurality of switches for driving the light emitting elements,
5. A rangefinder according to claim 4, wherein each switch is electrically connected to a plurality of light emitting elements within a corresponding line segment. 2. The distance measuring device according to claim 1, wherein said light emitting device irradiates said subject with light including one or more line lights extending in a third direction. 9. The distance measurement according to claim 8, wherein said light emitting device irradiates said subject with light including said one or more line lights extending in said third direction and one or more line lights extending in said fourth direction. Device. 2. The distance measuring device according to claim 1, wherein said light emitting device tilts its optical axis with respect to the optical axis of said light receiving device, and irradiates said subject with light from said light emitting element. 11. The distance measurement according to claim 10, wherein the light emitting device tilts its optical axis so that the zero-order light from the light emitting element is irradiated onto a region outside the light receiving range of the light receiving device. Device. The light emitting device emits light from the light emitting element such that the light from the light emitting element includes a plurality of spots of zero-order light, and the plurality of spots are irradiated to an area within a light receiving range of the light receiving device. 2. The distance measuring device according to claim 1, which irradiates the subject with light. 2. The distance measuring device according to claim 1, wherein timing of sequential lighting of said light emitting elements and timing of exposure in said light receiving device are synchronized. 2. The distance measuring device according to claim 1, wherein said light emitting device includes a collimating lens for collimating light from said light emitting element and irradiating said object with said light. 2. The distance measuring device according to claim 1, wherein said light emitting device comprises a diffraction optical element that forms light from said light emitting element by diffraction and irradiates said subject with the light. The light receiving device includes an imaging unit that captures the light irradiated to the subject,
2. The distance measuring device according to claim 1, wherein said distance measuring section measures the distance to said subject based on the light imaged by said imaging section. a light source including a plurality of light emitting elements that generate light;
and an optical element that irradiates a subject with light from the light emitting element,
A light-emitting device that irradiates the subject with light from the light-emitting elements by sequentially turning on the light-emitting elements one by one or each of a plurality of the light-emitting elements. 18. The light emitting device according to claim 17, wherein said optical element includes a collimating lens for collimating light from said light emitting element and irradiating said object with said light. 18. The light-emitting device according to claim 17, wherein said optical element includes a diffractive optical element that forms light from said light-emitting element by diffraction and irradiates said subject with the light. 18. The light emitting device according to claim 17, wherein the light reflected from the subject is received by a light receiving device.

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