Distance measurement system

Abstract

This invention provides a distance measurement system that can suppress misalignment of the optical axis of the projected light and suppress changes in the spot diameter of the projected light. [Solution] The distance measuring system 1A comprises a light source 110 that emits light, a collimator lens 120A, and a base member 130 that contacts the collimator lens 120A. The coefficient of linear expansion of the collimator lens 120A and the coefficient of linear expansion of the base member 130 are different, and at least one of the portion of the base member 130 that contacts the collimator lens 120A and the portion of the collimator lens 120A that contacts the base member 130 has an inclined surface that is tilted with respect to the optical axis Ax of the light source 110.

Description

[Technical Field]

[0001] This disclosure relates to a distance measurement system. [Background technology]

[0002] Distance measuring devices that measure the distance to an object using the Time of Flight (TOF) method are known. TOF distance measuring devices project a laser beam towards the object to be measured and receive the laser beam reflected from the object to detect the delay time between the projection of the laser beam and its reception. This allows the distance from the distance measuring device to the object to be measured to be calculated.

[0003] The distance measuring device comprises a light-emitting unit that emits light and a light-receiving unit that receives the light reflected from the object to be measured. The light-emitting unit comprises a light source that emits laser light to be emitted, a collimator lens for making the laser light emitted from the light source into parallel light, a holding member for holding the collimator lens, and a base member (housing), etc., on which the light source and the collimator lens are arranged.

[0004] In such distance measuring devices, the position of the collimator lens may shift from its predetermined position when the ambient temperature changes. Specifically, when the ambient temperature changes, various components such as the collimator lens, retaining member, and base member expand or contract due to the heat, and as a result, the collimator lens shifts from its predetermined position.

[0005] Therefore, in conventional light-emitting units having a semiconductor laser and a collimator lens, techniques have been proposed to suppress the positional displacement of the collimator lens. For example, Patent Document 1 discloses a lens support mechanism as this type of light-emitting unit, comprising a semiconductor laser element, a housing to which the semiconductor laser element is fixed, a collimator lens to which light emitted from the semiconductor laser element is incident, a first cylindrical member to which the collimator lens is fixed, and a second cylindrical member fitted to the first cylindrical member and fixed to the housing. In the lens support mechanism disclosed in Patent Document 1, the positional displacement between the light-emitting point of the light source and the collimator lens caused by thermal expansion and contraction is absorbed by making the linear expansion coefficient of the second cylindrical member and the linear expansion coefficient of the housing substantially the same. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2003 / 102940 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the structure disclosed in Patent Document 1, the coefficient of linear expansion of the first cylindrical member and the coefficient of linear expansion of the second cylindrical member are different. As a result, when the ambient temperature changes, loosening occurs between the first and second cylindrical members, causing a displacement of the collimator lens. Consequently, the optical axis of the projected light emitted from the light source is shifted.

[0008] Furthermore, if the collimator lens expands or contracts due to changes in ambient temperature, the curvature of the lens surface changes, which can alter the focal length of the collimator lens. As a result, the spot diameter of the light projected from the distance measuring device changes.

[0009] Thus, in conventional distance measuring devices, when the environmental temperature changes, there are problems such as displacement of the collimator lens, which causes the optical axis of the projected light to shift, or a change in the focal length of the collimator lens, which causes a change in the spot diameter of the projected light.

[0010] The present disclosure has been made in view of such problems, and an object thereof is to provide a distance measurement system that can suppress deviation of the optical axis of projected light and suppress changes in the spot diameter of projected light.

Means for Solving the Problems

[0011] To achieve the above object, one aspect of the distance measurement system according to the present disclosure includes a light source that emits light, a collimator lens, a base member that contacts the collimator lens, and a pressing member that presses the collimator lens. The linear expansion coefficient of the collimator lens is different from the linear expansion coefficient of the base member, and at least one of the portion of the base member that contacts the collimator lens and the portion of the collimator lens that contacts the base member has an inclined surface that is inclined with respect to the optical axis of the light source.

[0012] Another aspect of the distance measurement system according to the present disclosure includes a light source that emits light, a collimator lens, a holding member that holds the collimator lens, a base member that contacts the holding member, and a pressing member that presses the collimator lens. The linear expansion coefficient of the base member is different from the linear expansion coefficient of the holding member, and at least one of the portion of the base member that contacts the holding member and the portion of the holding member that contacts the base member has an inclined surface that is inclined with respect to the optical axis of the light source.

Advantages of the Invention

[0013] It is possible to suppress deviation of the optical axis of the projected light and suppress changes in the spot diameter of the projected light.

Brief Description of the Drawings

[0014] [Figure 1]Figure 1 shows a distance measuring device and an object to be measured according to Embodiment 1. [Figure 2] Figure 2 is a cross-sectional view showing the configuration of a distance measuring device according to Embodiment 1. [Figure 3] Figure 3 is a cross-sectional view showing the configuration of the light-emitting section in the distance measuring device according to Embodiment 1. [Figure 4] Figure 4 shows the configuration of the light-emitting section in the distance measuring device of the comparative example. [Figure 5] Figure 5 is a diagram illustrating the operation of the distance measuring device according to Embodiment 1. [Figure 6] Figure 6 is a semi-cross-sectional view of the light-emitting section in the distance measuring device according to Embodiment 1. [Figure 7] Figure 7 shows the change in the focal length of the collimator lens and the change in the distance between the collimator lens and the light source when the ambient temperature changes. [Figure 8] Figure 8 is a cross-sectional view showing the configuration of the light-emitting section in the distance measuring device according to Embodiment 2. [Figure 9] Figure 9 is a diagram illustrating the operation of the distance measuring device according to Embodiment 2. [Figure 10] Figure 10 is a cross-sectional view showing the configuration of the light-emitting section in a distance measuring device according to Modification 1. [Figure 11] Figure 11 is a cross-sectional view showing the configuration of the light-emitting section in a distance measuring device according to Modification 2. [Modes for carrying out the invention]

[0015] The embodiments of this disclosure will be described below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit this disclosure. Accordingly, any components in the following embodiments that are not described in the independent claims representing the highest-level concepts of this disclosure will be described as optional components.

[0016] Please note that each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, the scale and other aspects may not necessarily be consistent across all figures. In addition, the same reference numerals are used for substantially identical components in each figure, and redundant explanations are omitted or simplified. Furthermore, in this specification, the terms "up" and "down" do not necessarily refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial perception.

[0017] (Embodiment 1) First, the overall configuration of the distance measuring device 1 according to Embodiment 1 will be explained using Figures 1 and 2. Figure 1 is a diagram showing the distance measuring device 1 and the object to be measured 2 according to Embodiment 1. Figure 2 is a cross-sectional view showing the configuration of the distance measuring device 1 according to Embodiment 1.

[0018] As shown in Figure 1, the distance measuring device 1 is a distance measuring device that can measure the distance between the distance measuring device 1 and the object to be measured 2 using light such as laser light. In this embodiment, the distance measuring device 1 is a TOF sensor that measures the distance between the distance measuring device 1 and the object to be measured 2 using the TOF method. Furthermore, the distance measuring device 1 is a reflective 1D (one-dimensional) TOF sensor. Specifically, the distance measuring device 1 projects laser light toward the object to be measured 2 and receives the laser light (reflected light) reflected by the object to be measured 2, thereby detecting the delay time from when the laser light is projected until when it is received. This allows the distance from the distance measuring device 1 to the object to be measured 2 to be calculated.

[0019] In this embodiment, the distance measuring device 1 is a reflective TOF sensor, and therefore projects light toward the object 2 to measure the distance between the device 1 and the object 2. Specifically, the distance measuring device 1 projects laser light toward the object 2 as the light to measure the distance to the object 2.

[0020] As shown in Figure 2, the distance measuring device 1 comprises a light-emitting unit 100 that emits laser light as projected light, a light-receiving unit 200 that receives the laser light reflected by the object to be measured 2, and a housing 300 that holds the light-emitting unit 100 and the light-receiving unit 200.

[0021] The light-emitting unit 100 includes a light source 110 that emits laser light and a collimator lens 120 into which the light emitted from the light source 110 is incident. The detailed structure of the light-emitting unit 100 will be described later.

[0022] The light receiving unit 200 receives the projected light (reflected light) that is projected from the light transmitting unit 100 and reflected off the object to be measured 2. Specifically, since the light transmitting unit 100 projects laser light as projected light, the light receiving unit 200 receives the reflected light of the laser light that is projected from the light transmitting unit 100 and reflected off the object to be measured 2.

[0023] The light-receiving unit 200 includes a lens 210 that collects the projected light (reflected light) reflected by the object to be measured 2, and a light-receiving element 220 that receives the projected light collected by the lens 210.

[0024] The lens 210 focuses the laser light reflected from the object being measured 2 onto the light-receiving surface of the light-receiving element 220. For example, the lens 210 is a plano-convex lens.

[0025] The light-receiving element 220 is positioned at the focal point of the lens 210. The light-receiving element 220 is a photoelectric conversion element that receives laser light focused by the lens 210 and converts it into an electrical signal. In this embodiment, the distance measuring device 1 is a 1D-TOF sensor, so the light-receiving element 220 does not receive light containing two-dimensional information such as from a camera, but rather receives light containing one-dimensional information. For example, the light-receiving element 220 is a photodiode, photo IC diode, phototransistor, or photomultiplier tube.

[0026] The light-receiving element 220 outputs the converted electrical signal to the light-receiving circuit. The light-receiving circuit has, for example, an A / D conversion circuit. In this case, the light-receiving circuit converts the analog light-receiving signal corresponding to the amount of light received output from the light-receiving element 220 into a digital light-receiving signal using the A / D conversion circuit and outputs it to the control unit. Based on the light-receiving signal from the light-receiving circuit, the control unit calculates the time from when the laser beam is emitted from the light-emitting unit 100 until the laser beam reflected by the object to be measured 2 is received by the light-receiving element 220. That is, the control unit calculates the time required for the laser beam to travel back and forth between the distance measuring device 1 and the object to be measured 2. Then, based on the calculation result, the control unit calculates distance data (distance measurement result) indicating the distance from the distance measuring device 1 to the object to be measured 2 and outputs it to the outside from the output unit. The control unit is, for example, an IC (Integrated Circuit). The control unit is electrically connected to the light-emitting circuit, the light-receiving circuit and the output unit, and controls them.

[0027] The housing 300 houses the light-emitting unit 100 and the light-receiving unit 200. The housing 300 surrounds the light source 110 and the light-receiving element 220. The housing 300 also surrounds the lens 210. In this embodiment, the housing 300 is an outer enclosure member that constitutes the outer casing of the distance measuring device 1. Note that the housing 300 is not an outer enclosure member, and the distance measuring device 1 may have another outer enclosure member surrounding the housing 300. The housing 300 may be made of an insulating resin material or a metal material.

[0028] The distance measuring device 1 may also include a light receiving circuit, a light emitting circuit, a control unit, and an output unit. The circuit elements constituting each of the light receiving circuit, light emitting circuit, control unit, and output unit are mounted on one or more mounting boards (e.g., printed circuit boards).

[0029] Next, the detailed configuration of the light-emitting unit 100 in the distance measuring device 1 will be explained using Figure 3. Figure 3 is a cross-sectional view showing the configuration of the light-emitting unit 100 in the distance measuring device 1 according to Embodiment 1. Note that only the parts visible in the cross-section are shown in Figure 3. This is also the case in subsequent figures.

[0030] As shown in Figure 3, the light-emitting unit 100 comprises a light source 110, a collimator lens 120, a base member 130, a holding member 140, and a pressing member 150. The light-emitting unit 100 may also include other optical components such as lenses or mirrors.

[0031] The light source 110 emits light that will be projected. Specifically, the light source 110 is a semiconductor laser element that emits laser light. As the semiconductor laser element, for example, a TO-CAN package semiconductor laser element can be used. The laser light emitted by the light source 110 is, for example, near-infrared light with a central wavelength in the range of 800 nm to 1200 nm. However, the wavelength of the laser light emitted by the light source 110 is not particularly limited. For example, the laser light emitted by the light source 110 may be red light with a central wavelength of 635 nm to 800 nm.

[0032] The collimator lens 120 is an optical component that makes the light emitted from the light source 110 into parallel light. Specifically, the collimator lens 120 makes the laser light emitted from the light source 110 into parallel light. In other words, the laser light emitted from the light source 110 is incident on the collimator lens 120 and made into parallel light by the collimator lens 120. The laser light made into parallel light by the collimator lens 120 is projected to the outside as projected light from the light projection unit 100.

[0033] The collimator lens 120 is formed with a shape that is rotationally symmetric with respect to the optical axis (lens axis), which is the central axis of the collimator lens 120. The optical axis of the collimator lens 120 coincides with the optical axis Ax of the light source 110. The optical axis of the collimator lens 120 and the optical axis Ax of the light source 110 become the optical axis (transmitted light axis) of the light-emitting unit 100.

[0034] The collimator lens 120 has a lens body 121 and a flange portion 122 that protrudes from the lens body 121. The flange portion 122 protrudes radially outward from the lens body 121.

[0035] The lens body 121 has a light incident surface 121a and a light emission surface 121b. Light incident on the collimator lens 120 enters the lens body 121 from the light incident surface 121a, passes through the lens body 121, and exits the collimator lens 120 from the light emission surface 121b.

[0036] Light passing through the lens body 121 is subjected to optical action by the lens body 121. In this embodiment, light passing through the lens body 121 is subjected to optical action by the light emitting surface 121b. In other words, the light emitting surface 121b is a lens surface that imparts optical action to the light passing through the lens body 121. Specifically, light emitted from the light source 110 is subjected to optical action by the light emitting surface 121b (lens surface) and becomes parallel light. The light emitting surface 121b is a dome-shaped curved surface that is convex outward. The light incident surface 121a is a plane, but is not limited to this.

[0037] The collimator lens 120 is in contact with the holding member 140 and the pressing member 150, respectively. Specifically, the flange portion 122 of the collimator lens 120 is in contact with the holding member 140 and the pressing member 150, respectively.

[0038] In this embodiment, the portion of the flange portion 122 that contacts the retaining member 150 has an inclined surface 120a. The inclined surface 120a is formed to chamfer the upper corner of the flange portion 122. The inclined surface 120a is formed in an annular shape with respect to the optical axis of the collimator lens 120.

[0039] The inclined surface 120a is inclined with respect to the optical axis Ax of the light source 110. In other words, the inclined surface 120a is neither perpendicular nor horizontal with respect to the optical axis Ax of the light source 110. In this embodiment, the inclined surface 120a is a conical surface. Specifically, the inclined surface 120a is a conical surface of a cone centered on the optical axis Ax of the light source 110.

[0040] The inclined surface 120a is tilted so that it moves away from the optical axis Ax of the light source 110 as it approaches the light source 110. In other words, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surface 120a is negative.

[0041] The collimator lens 120 is formed into a predetermined shape using a light-transmitting material. Specifically, the collimator lens 120 is formed using a transparent resin material such as polycarbonate resin or acrylic resin, or a transparent material such as glass. In this embodiment, the collimator lens 120 is a resin molded product made of polycarbonate resin (PC).

[0042] The base member 130 is a base that supports the light source 110 and the collimator lens 120. The light source 110 is supported by the base member 130 by being fixed to the base member 130. The collimator lens 120 is supported by the base member 130 via the holding member 140 and the pressing member 150.

[0043] The base member 130 is a cylindrical body. The inner surface shape of the base member 130 is rotationally symmetric with respect to the cylindrical axis (central axis) of the base member 130. The cylindrical axis of the base member 130 coincides with the optical axis Ax of the light source 110.

[0044] In this embodiment, the base member 130 has a first cylindrical portion 131 with a constant inner diameter, a second cylindrical portion 132 with a changing inner diameter, and a third cylindrical portion 133 with a constant inner diameter.

[0045] A light source 110 is positioned in the first cylindrical section 131. A collimator lens 120 is positioned in the second cylindrical section 132. A retaining member 150 is positioned in the third cylindrical section 133.

[0046] The second cylindrical portion 132 is located between the first cylindrical portion 131 and the third cylindrical portion 133. The inner diameter of the third cylindrical portion 133 is larger than the inner diameter of the first cylindrical portion 131. In this embodiment, the inner surfaces of the first cylindrical portion 131, the second cylindrical portion 132, and the third cylindrical portion 133 are continuous. Therefore, the inner diameter of the second cylindrical portion 132 on the side facing the first cylindrical portion 131 is the same as the inner diameter of the first cylindrical portion 131, and the inner diameter of the second cylindrical portion 132 on the side facing the third cylindrical portion 133 is the same as the inner diameter of the third cylindrical portion 133.

[0047] The inner diameter of the second cylindrical portion 132 gradually changes from the first cylindrical portion 131 to the third cylindrical portion 133. Therefore, the inner surface of the second cylindrical portion 132 is an inclined surface 130a. The inclined surface 130a is inclined with respect to the optical axis Ax of the light source 110. In other words, the inclined surface 130a is neither perpendicular nor horizontal with respect to the optical axis Ax of the light source 110. The inclined surface 130a is a conical surface. The inclined surface 130a is formed in an annular shape with respect to the cylindrical axis of the base member 130.

[0048] The inclined surface 130a is tilted so that as it approaches the light source 110, it approaches the optical axis Ax of the light source 110. In other words, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surface 130a is positive.

[0049] The base member 130 is in contact with the holding member 140. Specifically, the inclined surface 130a of the second cylindrical portion 132 of the base member 130 is in contact with the holding member 140. In other words, the inclined surface 130a of the base member 130 is formed in the portion that is in contact with the holding member 140.

[0050] The base member 130 may be made of a resin material or a metal material. In this embodiment, the base member 130 is a resin molded product made of a resin material. For example, the base member 130 can be made of polybutylene terephthalate (PBT).

[0051] The base member 130 may be integrally formed with the housing 300 shown in Figure 2. In this case, the base member 130 may support the lens 210 and the light-receiving element 220 in the light-receiving unit 200. The base member 130 may also support other optical components.

[0052] The holding member 140 is a member that holds the collimator lens 120. In this embodiment, the holding member 140 has a mounting surface 141 on which the collimator lens 120 is placed. In other words, the collimator lens 120 is placed on the mounting surface 141 of the holding member 140. Specifically, the flange portion 122 of the collimator lens 120 is placed on the mounting surface 141 of the holding member 140.

[0053] The mounting surface 141 of the holding member 140 is a plane perpendicular to the optical axis Ax of the light source 110. The portion of the flange 122 that contacts the mounting surface 141 is also a plane perpendicular to the optical axis Ax of the light source 110. The collimator lens 120 is not fixed to the holding member 140, but is simply placed on the mounting surface 141.

[0054] The retaining member 140 is annular in shape and has a through hole 142. The retaining member 140 is rotationally symmetric with respect to its central axis. The central axis of the retaining member 140 coincides with the optical axis Ax of the light source 110. Laser light emitted from the light source 110 passes through the through hole 142 of the retaining member 140.

[0055] Furthermore, the retaining member 140 is supported by the base member 130. The retaining member 140 is housed inside the base member 130. Specifically, the retaining member 140 is supported by the second cylindrical portion 132 of the base member 130.

[0056] The retaining member 140 is in contact with the base member 130. Specifically, the retaining member 140 is in contact with the inner surface of the second cylindrical portion 132 of the base member 130. The portion of the retaining member 140 that is in contact with the base member 130 has an inclined surface 140a. The inclined surface 140a is inclined with respect to the optical axis Ax of the light source 110. In other words, the inclined surface 140a is neither perpendicular nor horizontal with respect to the optical axis Ax of the light source 110. The inclined surface 140a is a conical surface. The inclined surface 140a is formed on the outer circumferential surface of the retaining member 140. The inclined surface 140a is formed in an annular shape with respect to the central axis of the retaining member 140.

[0057] The inclined surface 140a is tilted so that as it approaches the light source 110, it approaches the optical axis Ax of the light source 110. In other words, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surface 130a is positive.

[0058] In this embodiment, since an inclined surface 130a is formed on the inner surface of the second cylindrical portion 132 of the base member 130, the holding member 140 is in contact with the inclined surface 130a of the base member 130. In other words, the inclined surface 140a of the holding member 140 and the inclined surface 130a of the base member 130 are in contact. In this embodiment, the inclination angle of the inclined surface 140a of the holding member 140 and the inclination angle of the inclined surface 130a of the base member 130 are the same. Therefore, the inclined surface 140a of the holding member 140 and the inclined surface 130a of the base member 130 are in surface contact.

[0059] The retaining member 140 is placed on the inclined surface 130a of the base member 130. The retaining member 140 is not fixed to the base member 130, but is placed on the inclined surface 130a of the base member 130.

[0060] The retaining member 140 is positioned between the collimator lens 120 and the base member 130. Specifically, the retaining member 140 is positioned between the flange portion 122 of the collimator lens 120 and the second cylindrical portion 132 of the base member 130. More specifically, the retaining member 140 is sandwiched between the outer surface of the flange portion 122 of the collimator lens 120 and the inclined surface 130a of the second cylindrical portion 132 of the base member 130.

[0061] The retaining member 140 may be made of a resin material or a metal material. In this embodiment, the retaining member 140 is a metal body made of a metal material. For example, the retaining member 140 can be made of stainless steel (SUS).

[0062] The retaining member 150 is a member that holds the collimator lens 120. The collimator lens 120 is pressed towards the light source 110 by the lower surface of the retaining member 150. The collimator lens 120, which is held in place by the retaining member 150, is sandwiched between the retaining member 150 and the base member 130.

[0063] In this embodiment, since the collimator lens 120 is held by the holding member 140, the collimator lens 120, which is pressed down by the pressing member 150, is sandwiched together with the holding member 140 by the pressing member 150 and the base member 130.

[0064] The retaining member 150 is annular in shape and has a through hole 151. The retaining member 150 is rotationally symmetric with respect to its central axis. The central axis of the retaining member 150 coincides with the optical axis Ax of the light source 110. Laser light emitted from the light source 110 passes through the through hole 151 of the retaining member 150. Specifically, laser light emitted from the light source 110 and parallelized by the collimator lens 120 passes through the through hole 151 of the retaining member 150.

[0065] The retaining member 150 is fixed to the base member 130. Specifically, the retaining member 150 is housed in the third cylindrical portion 133 of the base member 130 and fixed to the inner surface of the third cylindrical portion 133. In this embodiment, the retaining member 150 is fixed to the base member 130 by a bonding member 160 such as an adhesive. However, the method of fixing the retaining member 150 and the base member 130 is not limited to the bonding member 160. For example, the retaining member 150 may be fixed to the base member 130 by a screw. Alternatively, screw grooves may be formed in the joint portions of the retaining member 150 and the base member 130, and the retaining member 150 may be screwed into the base member 130 by rotating it. Alternatively, the retaining member 150 may be fixed to the base member 130 by press-fitting it.

[0066] The retaining member 150 is in contact with the collimator lens 120. Specifically, the inner surface of the retaining member 150 is in contact with the flange portion 122 of the collimator lens 120. The portion of the retaining member 150 that is in contact with the collimator lens 120 has an inclined surface 150a. The inclined surface 150a is inclined with respect to the optical axis Ax of the light source 110. In other words, the inclined surface 150a is neither perpendicular nor horizontal with respect to the optical axis Ax of the light source 110. The inclined surface 150a is a conical surface.

[0067] The inclined surface 150a is tilted so that it moves away from the optical axis Ax of the light source 110 as it approaches the light source 110. In other words, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surface 150a is negative.

[0068] The retaining member 150 is not fixed to the collimator lens 120, but rather presses down on the collimator lens 120.

[0069] In this embodiment, the portion of the collimator lens 120 that contacts the pressing member 150 has an inclined surface 120a. That is, the pressing member 150 presses against the inclined surface 120a of the collimator lens 120. For this reason, the pressing member 150 is in contact with the inclined surface 120a of the collimator lens 120. That is, the inclined surface 150a of the pressing member 150 and the inclined surface 120a of the collimator lens 120 are in contact. In this embodiment, the inclination angle of the inclined surface 150a of the pressing member 150 and the inclination angle of the inclined surface 120a of the collimator lens 120 are the same. Therefore, the inclined surface 150a of the pressing member 150 and the inclined surface 120a of the collimator lens 120 are in surface contact.

[0070] The pressing member 150 may be made of a resin material or a metal material. In this embodiment, the pressing member 150 is a metal body made of a metal material. For example, the pressing member 150 can be made of stainless steel (SUS). That is, the pressing member 150 is made of the same material as the holding member 140. Note that the pressing member 150 and the holding member 140 may be made of different materials.

[0071] In the distance measuring device 1 configured as described above, the linear expansion coefficient of the holding member 140 and the linear expansion coefficient of the base member 130 are different. Further, the linear expansion coefficient of the collimator lens 120 and the linear expansion coefficient of the holding member 140 are also different, and the linear expansion coefficient of the collimator lens 120 and the linear expansion coefficient of the pressing member 150 are also different. For example, let the linear expansion coefficient of the collimator lens 120 be α L and the linear expansion coefficient of the base member 130 be α B and the linear expansion coefficient of the holding member 140 be α H and the linear expansion coefficient of the pressing member 150 be α H2 Then, α B <α L , α H , α H2 , or α B >α L , α H , α H2 is in the relationship.

[0072] In this embodiment, the collimator lens 120 and the base member 130 are made of resin material, while the holding member 140 and the pressing member 150 are made of metal material. Therefore, the coefficients of linear expansion of the collimator lens 120 and the base member 130 are greater than the coefficients of linear expansion of the holding member 140 and the pressing member 150. Also, the coefficient of linear expansion of the base member 130 is greater than that of the collimator lens 120.

[0073] As an example, the collimator lens 120 has a coefficient of linear expansion α L 65×10 -6 The base member 130 is made of polycarbonate resin with a coefficient of linear expansion α B 94×10 -6 The retaining member 140 is made of polybutylene terephthalate resin with a coefficient of linear expansion α H 17×10 -6 The retaining member 150 is made of SUS304 with a temperature of / ℃ and has a coefficient of linear expansion α H2 17×10 -6 It is made of SUS304 with a temperature of / ℃.

[0074] Furthermore, the linear expansion coefficients of the collimator lens 120 and the base member 130 may be smaller than the linear expansion coefficients of the holding member 140 and the pressing member 150. Also, the linear expansion coefficient of the base member 130 may be smaller than that of the collimator lens 120. Furthermore, the linear expansion coefficients of the holding member 140 and the pressing member 150 may be the same or different. In this case, the linear expansion coefficient of the holding member 140 may be larger or smaller than that of the pressing member 150.

[0075] Next, the features of the distance measuring device 1 according to Embodiment 1 will be explained in comparison with the distance measuring device 1X of the comparative example, using Figures 4 and 5. Figure 4 is a diagram showing the configuration of the light-emitting unit 100X in the distance measuring device 1X of the comparative example. Figure 5 is a diagram illustrating the operation of the distance measuring device 1 according to Embodiment 1.

[0076] As shown in Figure 4, the light-emitting unit 100X in the comparative example distance measuring device 1X comprises a light source 110, a collimator lens 120X, a base member 130X, and a pressing member 150X. A stepped portion 131X is formed on the inner surface of the base member 130X, and the collimator lens 120X is placed on the mounting surface of the stepped portion 131X and pressed down by the pressing member 150X. The mounting surface of the stepped portion 131X is a plane perpendicular to the optical axis Ax of the light source 110.

[0077] Figure 4(a) shows the state before the ambient temperature changes, and Figure 4(b) shows the state after the ambient temperature changes. Specifically, Figure 4(b) shows the state when the ambient temperature increases.

[0078] As shown in Figure 4, in the comparative example distance measuring device 1X, the linear expansion coefficients of the collimator lens 120X, the base member 130X, and the retaining member 150X are different. Therefore, when the ambient temperature rises and the collimator lens 120X, base member 130X, and retaining member 150X undergo thermal expansion, loosening occurs between the collimator lens 120X and the base member 130X, as shown in Figure 4(b), causing a displacement of the collimator lens 120X. Specifically, the collimator lens 120X shifts in a direction perpendicular to the optical axis Ax of the light source 110 (horizontal direction). In addition, the collimator lens 120X may also shift in a direction parallel to the optical axis Ax of the light source 110 (vertical direction). As a result, the optical axis of the light emitted from the light source 110 is shifted from its predetermined position by the collimator lens 120X.

[0079] Furthermore, if the ambient temperature drops and the collimator lens 120X, base member 130X, and retaining member 150X undergo thermal contraction, the position of the collimator lens 120X will shift, causing the optical axis of the light projected from the light source 110 to shift.

[0080] Furthermore, when the ambient temperature changes and the collimator lens 120X expands or contracts due to thermal stress, the curvature of the lens surface of the collimator lens 120X (light-emitting surface 121b in Figure 4) changes, and the focal length of the collimator lens 120X changes. As a result, the spot diameter of the light emitted from the light-emitting section 100X of the distance measuring device 1X changes.

[0081] Thus, in the comparative example distance measuring device 1X, when the ambient temperature changes, the position of the collimator lens 120X shifts, causing the optical axis of the projected light to shift, or the focal length of the collimator lens 120X changes, causing the spot diameter of the projected light to change.

[0082] In contrast, in the distance measuring device 1 according to this embodiment, as shown in Figure 5, an inclined surface 130a is formed on the portion of the base member 130 that contacts the holding member 140, and the portion of the holding member 140 that contacts the base member 130 also has an inclined surface 140a. In other words, the boundary portion between the base member 130 and the holding member 140, which have different coefficients of linear expansion, is inclined with respect to the optical axis Ax of the light source 110.

[0083] This configuration, as shown in Figures 5(a) and 5(b), suppresses misalignment of the collimator lens 120 and also suppresses changes in the spot diameter of the projected light due to changes in the focal length of the collimator lens 120. This point will be explained below.

[0084] Figure 5(a) shows the state before the ambient temperature changes, and Figure 5(b) shows the state after the ambient temperature changes. Specifically, Figure 5(b) shows the state when the ambient temperature increases.

[0085] As shown in Figures 5(a) and 5(b), in the distance measuring device 1 according to this embodiment, an inclined surface 130a (first inclined surface) is formed on the base member 130 and an inclined surface 140a (second inclined surface) is formed on the holding member 140 at the contact portion between the base member 130 and the holding member 140.

[0086] As a result, as shown in Figure 5(b), when the ambient temperature rises and the base member 130 and the holding member 140 expand due to thermal expansion, the holding member 140, which is placed on the inclined surface 130a of the base member 130, moves in a direction parallel to the optical axis Ax of the light source 110. Consequently, the collimator lens 120 placed on the holding member 140 moves by a distance equivalent to the change in the focal length of the collimator lens 120, without the optical axis of the collimator lens 120 shifting from the optical axis Ax of the light source 110.

[0087] Similarly, when the ambient temperature decreases, the collimator lens 120 mounted on the holding member 140 moves by a distance equivalent to the change in the focal length of the collimator lens 120, without the optical axis of the collimator lens 120 shifting from the optical axis Ax of the light source 110.

[0088] As described above, with the distance measuring device 1 according to this embodiment, even if the ambient temperature changes, the positional displacement of the collimator lens 120 can be suppressed, thereby suppressing the shift in the optical axis of the projected light. Furthermore, since the collimator lens 120 moves without shifting from the optical axis Ax, the change in the spot diameter of the projected light due to a change in the focal length of the collimator lens 120 can be suppressed.

[0089] Furthermore, the structure disclosed in Patent Document 1 requires a distance from the collimator lens to the fitting position of the first cylindrical member and the second cylindrical member. Therefore, if there is no space on the side of the collimator lens opposite the light source (the light-emitting side of the collimator lens), it is structurally difficult to realize.

[0090] In contrast, in the distance measuring device 1 according to this embodiment, since only inclined surfaces 130a and 140a are formed at the boundary between the base member 130 and the holding member 140, which have different coefficients of linear expansion, a large structure is not required on the side of the collimator lens 120 opposite to the light source 110 (the light emission side of the collimator lens 120).

[0091] In other words, the distance measuring device 1 according to this embodiment has a space-saving structure, can suppress misalignment of the collimator lens 120, and can also suppress changes in the focal length of the collimator lens 120.

[0092] Furthermore, as shown in Figure 6, in the distance measuring device 1 according to this embodiment, the inclination of the inclined surfaces 130a and 140a is positive in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis. Figure 6 is a cross-sectional view of the distance measuring device 1 when cut by a plane passing through the optical axis Ax of the light source 110.

[0093] With this configuration, in a structure in which a retaining member 140 is placed inside a base member 130, an inclined surface 130a can be formed on the base member 130 and an inclined surface 140a can be formed on the retaining member 140 with a simple configuration.

[0094] Furthermore, in the cross-section shown in Figure 6, the focal length of the collimator lens 120 is denoted as f0, and the coefficient of linear expansion of the collimator lens 120 is denoted as α. L The coefficient of linear expansion of the base member 130 is set to α B The coefficient of linear expansion of the holding member 140 is set to α H Let T0 be the initial temperature, and let d0 (=f0) be the distance between the collimator lens 120 and the light source 110 at the initial temperature T0. When the straight line of the inclined surfaces 130a and 140a at the boundary between the base member 130 and the holding member 140 is expressed by the equation z = a1 × r + b1, the displacement of the collimator lens 120 in the +z direction when the ambient temperature changes by ΔT [°C] is Δd = b1 × α B ×ΔT+(d0-b1)×α H It is expressed as ×ΔT.

[0095] Furthermore, the change in focal length due to thermal expansion of the collimator lens 120 when the ambient temperature changes by ΔT [°C] is Δf = f0 × α L It is expressed as ×ΔT.

[0096] Therefore, for any ΔT, Δd ≈ Δf holds, meaning that the displacement of the collimator lens 120 in the +z direction is approximately equal to the change in the focal length f0 of the collimator lens 120. In other words, the spot diameter of the projected light emitted from the collimator lens 120 remains constant. The condition for Δd = Δf is b1 × (α B -α H ) ≈ f0 × (α L -α H )

[0097] Note that b1 × (α B -α H ) = f0 × (α L -α H By doing this, Δd=Δf, and the amount of displacement of the collimator lens 120 in the +z direction perfectly matches the change in the focal length f0 of the collimator lens 120.

[0098] For example, the collimator lens 120 is made of polycarbonate resin (coefficient of linear expansion α L = 65 × 10 -6 The base member 130 is made of polybutylene terephthalate resin (coefficient of linear expansion α) B = 94 × 10 -6 The holding member 140 and the pressing member are made of SUS304 (coefficient of linear expansion α) ( / ℃), and the holding member 140 and the pressing member are made of SUS304 (coefficient of linear expansion α) H , α H2 = 17 × 10 -6 It is composed of ( / ℃), and if the focal length f0 of the collimator lens 120 is f0 = 4.81 mm, then b1 = 3.00 mm.

[0099] Figure 7 shows the change in the focal length of the collimator lens and the change in the distance between the collimator lens and the light source when the ambient temperature changes from the initial temperature T0 of 25°C, in the distance measuring device 1X (comparative example) shown in Figure 4 and the distance measuring device 1 (example) according to this embodiment shown in Figure 5. The focal length f0 of the collimator lens 120 at the initial temperature T0 is f0 = 4.81 mm.

[0100] As shown in Figure 7, in the comparative example distance measuring device 1X (comparative example), it can be seen that when the ambient temperature changes, the distance between the collimator lens 120X and the light source 110 changes more than the change in the focal length of the collimator lens 120X. On the other hand, in the distance measuring device 1 according to this embodiment (example), it can be seen that even when the ambient temperature changes, the distance between the collimator lens 120 and the light source 110 changes by approximately the same distance as the change in the focal length of the collimator lens 120. In other words, in the distance measuring device 1 according to this embodiment, even when the ambient temperature changes, the spot diameter of the light emitted from the light-emitting unit 100 is kept almost constant.

[0101] Furthermore, as shown in Figures 3 and 5, the distance measuring device 1 according to this embodiment is equipped with a pressing member 150 that presses down on the collimator lens 120.

[0102] As a result, the collimator lens 120 is pressed down by the retaining member 150 in a direction parallel to the optical axis Ax of the light source 110, which suppresses loosening of the fixing point of the collimator lens 120 even when the ambient temperature changes. Therefore, displacement of the collimator lens 120 can be further suppressed.

[0103] Furthermore, in the distance measuring device 1 according to this embodiment, an inclined surface (another inclined surface) is formed at the boundary between the collimator lens 120 and the retaining member 150, which have different coefficients of linear expansion. Specifically, an inclined surface 120a (third inclined surface) is formed on the portion of the collimator lens 120 that contacts the retaining member 150, and an inclined surface 150a (fourth inclined surface) is formed on the portion of the retaining member 150 that contacts the collimator lens 120.

[0104] With this configuration, as shown in Figure 5(b), when the ambient temperature rises and the collimator lens 120 and the retaining member 150 undergo thermal expansion, the collimator lens 120 moves in a direction parallel to the optical axis Ax of the light source 110. As a result, the collimator lens 120 moves by a distance equivalent to the change in the focal length of the collimator lens 120, without its optical axis shifting from the optical axis Ax of the light source 110. The same applies when the ambient temperature decreases.

[0105] Therefore, the displacement of the collimator lens 120 can be further suppressed, thereby further suppressing the misalignment of the optical axis of the projected light, and the change in the focal length of the collimator lens 120 can be further suppressed, thereby further suppressing the change in the spot diameter of the projected light.

[0106] Furthermore, in the distance measuring device 1 according to this embodiment, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120 is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surfaces 120a and 150a is negative.

[0107] This configuration allows for the formation of an inclined surface 120a on the collimator lens 120 and an inclined surface 150a on the pressing member 150, in a structure in which the outer surface of the collimator lens 120 is pressed against by the pressing member 150, with a simple configuration.

[0108] Furthermore, in the cross-section of Figure 6, the coefficient of linear expansion of the retaining member 150 is α H2 Assuming the outer diameter of the collimator lens 120 is 2R, and the straight line of the inclined surfaces 120a and 150a at the boundary between the collimator lens 120 and the retaining member 150 is z = a² × r + b², then f₀ × (α B -α L ) ≈ -a² × R(α L -α H2 It is good if the relationship between the two conditions is satisfied.

[0109] This configuration further suppresses changes in the focal length of the collimator lens 120 when the ambient temperature changes, thereby further suppressing changes in the spot diameter of the projected light.

[0110] (Embodiment 2) Next, the distance measuring device 1A according to Embodiment 2 will be described with reference to Figure 8. Figure 8 is a cross-sectional view showing the configuration of the light-emitting unit 100A in the distance measuring device 1A according to Embodiment 2.

[0111] As shown in Figure 8, the distance measuring device 1A according to this embodiment does not have a holding member 140 compared to the distance measuring device 1 according to Embodiment 1, and the collimator lens 120A is directly supported by the base member 130. Specifically, the collimator lens 120A is placed on the inclined surface 130a of the base member 130 and supported by the base member 130.

[0112] The portion of the collimator lens 120A that contacts the base member 130 has an inclined surface 120b. In other words, the collimator lens 120A has an inclined surface 120b in addition to the inclined surface 120a. The inclined surface 120b is formed to chamfer the lower corner of the flange portion 122A. Similar to the inclined surface 120a, the inclined surface 120b is formed in an annular shape around the optical axis of the collimator lens 120A.

[0113] The inclined surface 120b is inclined with respect to the optical axis Ax of the light source 110. In other words, the inclined surface 120b is neither perpendicular nor horizontal with respect to the optical axis Ax of the light source 110. In this embodiment, the inclined surface 120b is a conical surface.

[0114] Unlike the inclined surface 120a that contacts the retaining member 150, the inclined surface 120b that contacts the base member 130 is inclined so that it approaches the optical axis Ax of the light source 110 as it approaches the light source 110. In other words, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120A is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surface 120b is positive.

[0115] In this embodiment, since an inclined surface 130a is formed on the base member 130 in the portion that the collimator lens 120A contacts, the collimator lens 120A is in contact with the inclined surface 130a of the base member 130. In other words, the inclined surface 120b of the collimator lens 120A and the inclined surface 130a of the base member 130 are in contact. The inclination angle of the inclined surface 120b of the collimator lens 120A and the inclination angle of the inclined surface 130a of the base member 130 are the same. Therefore, the inclined surface 120b of the collimator lens 120A and the inclined surface 130a of the base member 130 are in surface contact.

[0116] The other components are the same as those of the distance measuring device 1 in Embodiment 1 described above.

[0117] Next, the features of the distance measuring device 1A according to Embodiment 2 will be explained using Figure 9. Figure 9 is a diagram illustrating the operation of the distance measuring device 1A according to Embodiment 2.

[0118] As shown in Figure 9, in the distance measuring device 1A according to this embodiment, an inclined surface 130a is formed on the portion of the base member 130 that is in contact with the collimator lens 120A, and an inclined surface 120b is formed on the portion of the collimator lens 120A that is in contact with the base member 130. In other words, the boundary portion between the base member 130 and the collimator lens 120A, which have different coefficients of linear expansion, is inclined with respect to the optical axis Ax of the light source 110.

[0119] This configuration, as shown in Figures 9(a) and (b), suppresses misalignment of the collimator lens 120A and also suppresses changes in the focal length of the collimator lens 120A. This point will be explained below.

[0120] Figure 9(a) shows the state before the ambient temperature changes, and Figure 9(b) shows the state after the ambient temperature changes. Specifically, Figure 9(b) shows the state when the ambient temperature increases.

[0121] As shown in Figures 9(a) and 9(b), in the distance measuring device 1A according to this embodiment, an inclined surface 130a (first inclined surface) is formed on the base member 130 and an inclined surface 120b (second inclined surface) is formed on the collimator lens 120A at the contact portion between the base member 130 and the collimator lens 120A. As a result, as shown in Figure 9(b), when the ambient temperature rises and the base member 130 and collimator lens 120A undergo thermal expansion, the collimator lens 120A, which is placed on the inclined surface 130a of the base member 130, moves in a direction parallel to the optical axis Ax of the light source 110. As a result, the collimator lens 120A placed on the base member 130 moves by a distance equivalent to the change in the focal length of the collimator lens 120A, without the optical axis of the collimator lens 120A shifting from the optical axis Ax of the light source 110.

[0122] Similarly, when the ambient temperature decreases, the collimator lens 120A mounted on the base member 130 moves by a distance equivalent to the change in the focal length of the collimator lens 120A, without the optical axis of the collimator lens 120A shifting from the optical axis Ax of the light source 110.

[0123] As described above, with the distance measuring device 1A according to this embodiment, even if the ambient temperature changes, the positional displacement of the collimator lens 120A can be suppressed, thereby suppressing the shift in the optical axis of the projected light. Furthermore, since the change in the focal length of the collimator lens 120A can be suppressed, the change in the spot diameter of the projected light can be suppressed.

[0124] Furthermore, in the distance measuring device 1A according to this embodiment, similar to the first embodiment described above, it is possible to suppress misalignment of the collimator lens 120A with a space-saving structure, and to suppress changes in the focal length of the collimator lens 120A.

[0125] Furthermore, as shown in Figure 9, in the distance measuring device 1A according to this embodiment, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120A is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surfaces 120b and 130a is positive.

[0126] With this configuration, in a structure in which a collimator lens 120A is placed inside the base member 130, an inclined surface 130a can be formed on the base member 130 and an inclined surface 120b can be formed on the collimator lens 120A with a simple configuration.

[0127] Furthermore, in the cross-section of Figure 8, when the straight lines of the inclined surfaces 120b and 130a at the boundary between the collimator lens 120A and the base member 130 are expressed by the equation z = a1 × r + b1, it is desirable that b1 ≈ 0. In other words, the plane formed by extending the inclined surfaces 120b and 130a should pass near the light-emitting point 110a of the light source 110. This ensures that the displacement of the collimator lens 120A in the z direction is approximately equal to the change in the focal length of the collimator lens 120A. Therefore, even if the ambient temperature changes, the distance between the collimator lens 120A and the light source 110 changes by approximately the same distance as the change in the focal length of the collimator lens 120A. In other words, even if the ambient temperature changes, the spot diameter of the light emitted from the light-emitting unit 100A remains approximately constant. b1 ≈ 0 means that if the focal length is f0, then -0.5 × f0 <b1<0.5×f0である。

[0128] Furthermore, it is even better if b1=0. This ensures that the displacement of the collimator lens 120A in the z direction perfectly matches the change in the focal length of the collimator lens 120A. Therefore, even if the ambient temperature changes, the spot diameter of the light emitted from the light emitter 100A can be kept constant.

[0129] Furthermore, the distance measuring device 1A according to this embodiment also includes a pressing member 150 that presses down on the collimator lens 120A.

[0130] As a result, the collimator lens 120A is pressed down by the retaining member 150 in a direction parallel to the optical axis Ax of the light source 110, which suppresses loosening of the fixing point of the collimator lens 120A even when the ambient temperature changes. Therefore, displacement of the collimator lens 120A can be further suppressed.

[0131] Furthermore, in the distance measuring device 1A according to this embodiment, an inclined surface 120a (third inclined surface) is formed on the portion of the collimator lens 120A that contacts the retaining member 150, and an inclined surface 150a (fourth inclined surface) is formed on the portion of the retaining member 150 that contacts the collimator lens 120A.

[0132] With this configuration, as shown in Figure 9(b), when the ambient temperature rises and the collimator lens 120A and the retaining member 150 undergo thermal expansion, the collimator lens 120A moves in a direction parallel to the optical axis Ax of the light source 110. As a result, the collimator lens 120A moves by a distance equivalent to the change in the focal length of the collimator lens 120A, without its optical axis shifting from the optical axis Ax of the light source 110.

[0133] Therefore, the displacement of the collimator lens 120A can be further suppressed, thereby further suppressing the shift in the optical axis of the projected light, and the change in the focal length of the collimator lens 120A can be further suppressed, thereby further suppressing the change in the spot diameter of the projected light.

[0134] Furthermore, in the distance measuring device 1A according to this embodiment, in a cylindrical coordinate system where the light emission point 110a of the light source 110 is the origin, the optical axis Ax of the light source 110 is the z axis, the direction in which the collimator lens 120A is positioned relative to the light emission point 110a is the positive direction, and the radial direction of the optical axis Ax of the light source 110 is the r axis, the inclination of the inclined surfaces 120b and 130a is positive.

[0135] With this configuration, in a structure in which a collimator lens 120A is placed inside the base member 130, an inclined surface 130a can be formed on the base member 130 and an inclined surface 120b can be formed on the collimator lens 120A with a simple configuration.

[0136] In this embodiment, the distance measuring device 1A does not have a holding member 140, but by adding a holding member 140 as in Embodiment 1 above, the structure of the collimator lens 120 can be simplified. In other words, in this embodiment, the collimator lens 120A has both an inclined surface 120a and an inclined surface 120b, but in Embodiment 1, the collimator lens 120 does not have an inclined surface 120b and only has an inclined surface 120a. Therefore, the collimator lens 120 in Embodiment 1 has a simpler structure than the collimator lens 120A in this embodiment.

[0137] (modified version) The distance measuring device relating to this disclosure has been described above based on Embodiments 1 and 2, but this disclosure is not limited to Embodiments 1 and 2.

[0138] For example, in the above embodiment 1, an inclined surface was formed on each of the base member 130 and the holding member 140 at the contact portion between the base member 130 and the holding member 140, but the embodiment is not limited to this.

[0139] Specifically, as shown in Figure 10 of the light-emitting section 100B of the distance measuring device 1B, at the contact portion between the base member 130B and the holding member 140, an inclined surface 140a may be formed only on the portion of the holding member 140 that contacts the base member 130B, without forming an inclined surface on the portion of the base member 130B that contacts the holding member 140. In Figure 10, a stepped portion 134 is formed on the base member 130B, and the inclined surface 140a of the holding member 140 is in contact with the corner of the stepped portion 134 of the base member 130B.

[0140] On the other hand, as shown in the light-emitting section 100C of the distance measuring device 1C in Figure 11, in the contact portion between the base member 130 and the holding member 140C, an inclined surface 130a may be formed only on the portion of the base member 130 that contacts the holding member 140C, without forming an inclined surface on the portion of the holding member 140C that contacts the base member 130. In Figure 11, the lower corner of the holding member 140C is in contact with the inclined surface 130a of the base member 130.

[0141] Thus, at the contact portion between the base member 130 and the holding member 140, it is sufficient that an inclined surface is formed on at least one of the base member 130 and the holding member 140. In other words, it is sufficient that at least one of the portion of the base member 130 that contacts the holding member 140 and the portion of the holding member 140 that contacts the base member 130 has an inclined surface.

[0142] Since it is difficult to accurately machine the angles of the inclined surfaces of both the base member 130 and the holding member 140, it is preferable to form an inclined surface on only one of the parts of the base member 130 that contacts the holding member 140 and the part of the holding member 140 that contacts the base member 130, as shown in Figures 10 and 11. In other words, at the contact portion between the base member 130 and the holding member 140, it is preferable to form an inclined surface on one of the base member 130 and the holding member 140, leaving the other part as a corner without forming an inclined surface, so that the inclined surface and the corner are in contact. In this case, it is sufficient to accurately machine only the part of the base member 130 and the holding member 140 on which the inclined surface is formed. Furthermore, even when inclined surfaces are formed on both the base member 130 and the holding member 140, as in Embodiment 1 above, the base member 130 and the holding member 140 can be easily formed by shortening the length of the inclined surface, which is the machined surface where accuracy is required.

[0143] Furthermore, in the above embodiments 1 and 2, inclined surfaces were formed on the collimator lens 120 and the retaining member 150 at the contact portion between the collimator lens 120 and the retaining member 150, but the invention is not limited to this.

[0144] Specifically, as shown in Figure 10 of the light-emitting section 100B of the distance measuring device 1B, at the contact portion between the collimator lens 120B and the retaining member 150, an inclined surface 150a may be formed only on the portion of the retaining member 150 that contacts the collimator lens 120B, without forming an inclined surface on the portion of the collimator lens 120B that contacts the retaining member 150. In Figure 10, the upper corner of the collimator lens 120B is in contact with the inclined surface 150a of the retaining member 150.

[0145] On the other hand, as shown in the light-emitting section 100C of the distance measuring device 1C in Figure 11, in the contact portion between the collimator lens 120 and the retaining member 150C, an inclined surface 120a may be formed only on the portion of the collimator lens 120 that contacts the retaining member 150C, without forming an inclined surface on the portion of the retaining member 150C that contacts the collimator lens 120. In Figure 11, the lower corner of the retaining member 150C is in contact with the inclined surface 120a of the collimator lens 120.

[0146] Thus, at the contact portion between the collimator lens 120 and the retaining member 150, it is sufficient that an inclined surface is formed on at least one of the collimator lens 120 and the retaining member 150. It is sufficient that an inclined surface is formed on at least one of the portion of the collimator lens 120 that contacts the retaining member 150 and the portion of the retaining member 150 that contacts the collimator lens 120.

[0147] Since it is difficult to accurately machine the angles of the inclined surfaces of both the collimator lens 120 and the retaining member 150, it is preferable to form an inclined surface on only one of the parts of the collimator lens 120 that contacts the retaining member 150 and the part of the retaining member 150 that contacts the collimator lens 120. In other words, at the contact portion between the collimator lens 120 and the retaining member 150, it is preferable to form an inclined surface on one of the collimator lens 120 and the retaining member 150, leaving the other part as a corner without forming an inclined surface, so that the inclined surface and the corner are in contact. In this case, it is sufficient to accurately machine only the part of the collimator lens 120 and the retaining member 150 that has the inclined surface. Furthermore, even when inclined surfaces are formed on both the collimator lens 120 and the retaining member 150 as in the embodiments 1 and 2 above, the collimator lens 120 and the retaining member 150 can be easily formed by shortening the length of the inclined surface, which is the machined surface where accuracy is required.

[0148] Furthermore, in the contact portion between the collimator lens 120 and the retaining member 150 in the above embodiments 1 and 2, it is not necessary for either the collimator lens 120 or the retaining member 150 to have an inclined surface. For example, in the distance measuring devices 1 and 1A in the above embodiments 1 and 2, the collimator lens 120 and the retaining member 150 may be replaced with the collimator lens 120X and the retaining member 150X in the comparative example distance measuring device 1X shown in Figure 4. In this case, the retaining member 150X will press against the upper surface of the flange portion of the collimator lens 120X (a plane perpendicular to the optical axis Ax).

[0149] Furthermore, in the above embodiment 2, an inclined surface 130a is formed on the portion of the base member 130 that contacts the collimator lens 120A, and an inclined surface 120b is formed on the portion of the collimator lens 120A that contacts the base member 130, but the embodiment is not limited to this.

[0150] Specifically, although not shown in the figures, at the contact portion between the collimator lens 120A and the base member 130, an inclined surface 120b may be formed only on the portion of the collimator lens 120A that contacts the base member 130, without forming an inclined surface on the portion of the base member 130 that contacts the collimator lens 120A. Alternatively, at the contact portion between the collimator lens 120A and the base member 130, an inclined surface 130a may be formed only on the portion of the base member 130 that contacts the collimator lens 120A, without forming an inclined surface on the portion of the collimator lens 120A that contacts the base member 130. In other words, at the contact portion between the collimator lens 120A and the base member 130, the structure may be such that the inclined surface and the corner are in contact.

[0151] As described above, in the second embodiment, it is sufficient that an inclined surface is formed on at least one of the portions of the base member 130 that contact the collimator lens 120A and the portions of the collimator lens 120A that contact the base member 130. However, since it is difficult to precisely machine the angles of the inclined surfaces of the base member 130 and the collimator lens 120A, it is preferable to form an inclined surface on only one of the portions of the base member 130 that contact the collimator lens 120A and the portions of the collimator lens 120A that contact the base member 130.

[0152] Furthermore, in embodiments 1 and 2 described above, the inclined surfaces 120a, 120b, 130a, 140a, and 150a were flat, but are not limited to this. That is, in a cross-sectional view, the inclined lines of the inclined surfaces 120a, 120b, 130a, 140a, and 150a were straight lines, but are not limited to this. For example, the inclined surfaces 120a, 120b, 130a, 140a, and 150a may be curved surfaces. Specifically, in a cross-sectional view, the inclined lines of the inclined surfaces 120a, 120b, 130a, 140a, and 150a may be curves such as circular arcs.

[0153] Furthermore, in embodiments 1 and 2 described above, the inclination angles of the inclined surfaces 120a, 120b, 130a, 140a, and 150a may be the same or different from each other. Alternatively, the inclination angles at two contact points (for example, in embodiment 1, the inclination angles between inclined surface 120a and inclined surface 150a, and between inclined surface 130a and inclined surface 140a) may be the same, while the inclination angles at one of the two contact points may be different.

[0154] Furthermore, in embodiments 1 and 2 described above, the distance measuring device 1 was a reflective TOF sensor, but it is not limited to this. For example, the distance measuring device 1 may be a transmissive TOF sensor.

[0155] Furthermore, the distance measuring device 1 in the above embodiments 1 and 2 may be configured as a distance measuring system. In other words, although the multiple components constituting the distance measuring device 1 in the above embodiments 1 and 2 were configured with their functions integrated into a single device, their functions may be separated into multiple devices.

[0156] Furthermore, this disclosure also includes forms obtained by applying various modifications to Embodiments 1 and 2 described above that a person skilled in the art could conceive, as well as forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of this disclosure. In addition, this disclosure also includes any combination of two or more claims from the multiple claims described in the claims at the time of filing this application, provided that they are not technically contradictory. For example, if the cited claims described in the claims at the time of filing this application are made into a multi-claim or multi-multi-claim so as to refer to all of the higher-level claims without technically contradictory, then all combinations of claims included in that multi-claim or multi-multi-claim are also included in this disclosure. [Industrial applicability]

[0157] This disclosure is suitable for distance measuring devices for measuring the distance to an object, and is particularly suitable for TOF (Time-of-Flight) type distance measuring devices. [Explanation of symbols]

[0158] 1, 1A, 1B, 1C distance measuring device 2. Object to be measured 100, 100A, 100B, 100C Light-emitting section 110 Light source 110a Light source 120, 120A, 120B Collimator Lens 120a, 120b, 130a, 140a, 150a Slope 121 Lens body 121a Light entrance surface 121b Light exit surface 122, 122A Flange section 130, 130B base member 131 First cylinder part 132 Second cylinder part 133 Third cylinder part 134 Stepped section 140, 140C retaining member 141 Mounting surface 142, 151 Through holes 150, 150C retaining member 160 Joining members 200 Light receiving section 210 Lens 220 light-receiving elements 300 cabinets Ax optical axis

Claims

1. A light source that emits light, Collimator lens and A base member that contacts the collimator lens, The system includes a retaining member for holding down the collimator lens, The linear expansion coefficient of the collimator lens and the linear expansion coefficient of the base member are different. At least one of the portion of the base member that contacts the collimator lens and the portion of the collimator lens that contacts the base member has an inclined surface that is inclined with respect to the optical axis of the light source. Distance measurement system.

2. In a cylindrical coordinate system where the light emission point of the light source is the origin, the optical axis is the z-axis, the direction in which the collimator lens is positioned relative to the light emission point is the positive direction, and the radial direction of the optical axis is the r-axis, the inclination of the inclined surface is positive. The distance measuring system according to claim 1.

3. In the cross-section of the distance measuring device when cut by a plane passing through the optical axis, the inclined surface is z = a １ ×r+b １ If so, b １ ≈ 0 The distance measuring system according to claim 2.

4. The base member has a first inclined surface as the inclined surface formed in the portion that contacts the collimator lens. The distance measuring system according to claim 1.

5. The collimator lens has a second inclined surface as the inclined surface formed in the portion that contacts the base member. The distance measuring system according to claim 1.

6. The base member has a first inclined surface formed in the portion that contacts the collimator lens, The collimator lens has a second inclined surface formed as the inclined surface in the portion that contacts the base member, The first inclined surface and the second inclined surface are in surface contact. The distance measuring system according to claim 1.

7. A light source that emits light, Collimator lens and A holding member for holding the collimator lens, A base member in contact with the aforementioned holding member, The system includes a retaining member for holding down the collimator lens, The coefficient of linear expansion of the base member and the coefficient of linear expansion of the holding member are different. At least one of the portion of the base member that contacts the holding member and the portion of the holding member that contacts the base member has an inclined surface that is inclined with respect to the optical axis of the light source. Distance measurement system.

8. Let the linear expansion coefficient of the collimator lens be α Ｌ and the linear expansion coefficient of the base member be α Ｂ and the linear expansion coefficient of the holding member be α Ｈ . Then, α Ｂ <α Ｌ , α Ｈ , or α Ｂ >α Ｌ , α Ｈ are in the relationship of In a cylindrical coordinate system where the light emission point of the light source is the origin, the optical axis is the z-axis, the direction in which the collimator lens is positioned relative to the light emission point is the positive direction, and the radial direction of the optical axis is the r-axis, the inclination of the inclined surface is positive. The distance measuring system according to claim 7.

9. In the cross-section of the distance measuring device when cut by a plane passing through the optical axis, the focal length of the collimator lens is f. ０ Let the inclined surface be z = a １ ×r+b １ If so, b １ × (α Ｂ -α Ｈ ) ≈ f ０ × (α Ｌ -α Ｈ The relationship satisfies the following: The distance measuring system according to claim 8.

10. The base member has a first inclined surface as the inclined surface formed in the portion that contacts the holding member. The distance measuring system according to claim 7.

11. The holding member has a second inclined surface formed on the portion that contacts the base member. The distance measuring system according to claim 7.

12. The base member has a first inclined surface formed on the portion that contacts the holding member, The holding member has a second inclined surface formed as the inclined surface in the portion that contacts the base member, The first inclined surface and the second inclined surface are in surface contact. The distance measuring system according to claim 7.

13. The coefficient of linear expansion of the collimator lens and the coefficient of linear expansion of the retaining member are different. At least one of the portion of the collimator lens that contacts the retaining member and the portion of the retaining member that contacts the collimator lens has another inclined surface that is inclined with respect to the optical axis of the light source. A distance measuring system according to any one of claims 7 to 12.

14. In a cylindrical coordinate system where the light emission point of the light source is the origin, the optical axis is the z-axis, the direction in which the collimator lens is positioned relative to the light emission point is the positive direction, and the radial direction of the optical axis is the r-axis, the inclination of the other inclined surface is negative. The distance measuring system according to claim 13.

15. The coefficient of linear expansion of the aforementioned pressing member is α Ｈ２ The outer diameter of the collimator lens is set to 2R, and the coefficient of linear expansion of the collimator lens is set to α Ｌ The coefficient of linear expansion of the base member is set to α Ｂ The coefficient of linear expansion of the holding member is set to α Ｈ The focal length of the collimator lens is set to f ０ Assuming that the cross-section of the distance measuring device is cut by a plane passing through the optical axis, the other inclined surface is z = a ２ ×r+b ２ Then, f ０ × (α Ｂ -α Ｌ ) ≈ -a ２ ×R(α) Ｌ -α Ｈ２ The relationship satisfies the following: The distance measuring system according to claim 14.

16. The retaining member is fixed to the base member by a joining member, screwing, or press-fitting. A distance measuring system according to any one of claims 1 to 12.

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