Reflector

Abstract

To enable reflectance of a reflector to be easily changed.SOLUTION: A reflector 10 includes: a reflective member 110; and a mask member 120. A surface of the reflective member 110 facing a measuring device 20 is a reference reflecting surface. The reference reflecting surface is, for example, a Lambertian reflector surface. The mask member 120 is overlapped on at least a part of the reference reflecting surface of the reflective member 110 and inhibits at least a part of light irradiated by the reflective member 10 from reaching the reference reflecting surface. Then, the mask member 120 is replaceable.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reflector used for inspecting a measuring device that measures the distance to an object by an optical method. [Background technology]

[0002] In recent years, the use of measuring devices that measure the distance to an object using optical methods has expanded. In such measuring devices, it is important to check whether the distance is being measured normally. For example, Patent Document 1 describes the use of an optical axis adjustment device having a front plate and a rear plate when measuring the deviation of the optical axis of the measuring device. The front plate is located in front of the rear plate and has a hole for transmitting the light emitted from the measuring device. In Patent Document 1, the light emitted from the measuring device passes through the hole without being blocked by the front plate and is irradiated to the rear plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-56662 A Summary of the Invention [Problem to be solved by the invention]

[0004] There are many different types of objects that can be measured by a measuring device. Therefore, the reflectance of light on the objects varies. Therefore, when inspecting a measuring device, it is necessary to perform inspections that take into account a variety of reflectances.

[0005] One example of an object of the present invention is to make it possible to easily change the reflectance of a reflector used in testing a measuring device that measures the distance to an object by an optical method. [Means for solving the problem]

[0006] The invention described in claim 1 is a reflector used for inspecting a measuring device that measures a distance to an object by an optical method, a reflecting member having a reference reflecting surface that reflects light irradiated from the measuring device; a mask member that is overlapped with at least a portion of the reference reflecting surface and that blocks at least a portion of the light from reaching the reference reflecting surface; Equipped with The mask member is a replaceable reflector. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram for explaining a usage environment of a reflector according to an embodiment. [Diagram 2] FIG. 2 is a plan view showing a first example of a mask member. [Diagram 3] FIG. 13 is a diagram for explaining the size of a partial region. [Figure 4] 13(A) and 13(B) are diagrams showing a first example of a light-transmitting region and a light-shielding region in a partial region. [Diagram 5] 13(A) and 13(B) are diagrams showing a second example of a light-transmitting region and a light-shielding region in a partial region. [Figure 6] 13(A) and 13(B) are diagrams showing a third example of a light-transmitting region and a light-shielding region in a partial region. [Figure 7] 13(A) and 13(B) are diagrams showing a third example of a light-transmitting region and a light-shielding region in a partial region. [Figure 8] 1. FIG. 4 is a diagram showing a modified example of the reflector shown in FIG. [Figure 9] FIG. 9 is a diagram for explaining the purpose of installing the mask member shown in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are given the same reference numerals and the description will be omitted as appropriate.

[0009] 1 is a diagram for explaining a usage environment of a reflector 10 according to an embodiment. The reflector 10 is used together with an analysis device 30, and is used for inspecting a measurement device 20.

[0010] The measuring device 20 is, for example, a LiDAR, and measures the distance to an object using an optical method. Specifically, the measuring device 20 has a light emitting unit and a light receiving unit, and measures the distance to the object using the time from when the light emitting unit emits light (for example, laser light) to when the light receiving unit receives the light reflected by the object. When the measuring device 20 is a LiDAR, the measuring device 20 measures the distance to the object discretely by emitting a pulsed laser, which is an electromagnetic wave, in a predetermined angular range in the horizontal and vertical directions, and generates three-dimensional measurement point cloud information indicating the position of the object.

[0011] In the inspection of the measuring device 20, the distance from the measuring device 20 to the reflector 10 is set to a predetermined distance L1. In this state, the measuring device 20 measures the reflector 10. The analyzing device 30 uses the measurement result to determine whether or not the measuring device 20 is normal.

[0012] In the example shown in this figure, the reflector 10 has a reflecting member 110 and a mask member 120 .

[0013] The surface of the reflecting member 110 facing the measuring device 20 is a reflecting surface (hereinafter, referred to as a reference reflecting surface). The reflectance of the reference reflecting surface is constant regardless of the position on the surface. The reference reflecting surface is, for example, a Lambertian reflector surface that is a retroreflective surface.

[0014] The mask member 120 is superimposed on at least a partial area of ​​the reference reflecting surface of the reflecting member 110, and prevents at least a part of the light irradiated by the reflector 10 from reaching the reference reflecting surface. The mask member 120 is replaceable. Therefore, the reflectance of the reflector 10 can be easily changed by changing the mask member 120. The reference reflecting surface of the reflecting member 110 may be flat, or may be curved in at least one of the width direction and the height direction. In the latter case, the reflecting member 110 is curved in a direction such that the reference reflecting surface is concave, for example.

[0015] FIG. 2 is a plan view showing a first example of the mask member 120. The mask member 120 has a light-transmitting region 122 and a light-shielding region 124. The light transmittance of the mask member 120 is determined by the occupancy rate of the light-transmitting region 122 (or the occupancy rate of the light-shielding region 124). For example, the mask member 120 is formed by applying a light-shielding paint to a part of a plate-shaped base material having light-transmittance (for example, the transmittance of light irradiated by the measuring device 20 is 90% or more, preferably 99% or more). In this case, the region of the base material where the paint is not applied is the light-transmitting region 122, and the region of the base material where the paint is applied is the light-shielding region 124. However, the mask member 120 may be formed by providing a plurality of openings in a light-shielding base material. In this case, the region of the base material where the openings are provided is the light-transmitting region 122, and the region of the base material where the openings are not provided is the light-shielding region 124.

[0016] Moreover, in the example shown in the figure, the mask member 120 has a plurality of partial regions 126. Each of the plurality of partial regions 126 has a light-transmitting region 122 and a light-shielding region 124. The light transmittance of these plurality of partial regions 126 is different from one another. However, within one partial region 126, the light transmittance is constant. Therefore, by overlapping the partial regions 126 on the reflecting member 110, it is possible to perform inspections related to a plurality of reflectances without changing the partial regions 126.

[0017] In the example shown in the figure, the occupancy rates of the light-transmitting regions 122 (or the occupancy rates of the light-shielding regions 124) of the partial regions 126 are different from one another. The partial regions 126 are arranged in the width direction of the reflecting member 110 (i.e., the width direction of the mask member 120). The light transmittance of the partial regions 126 decreases toward the right (or toward the left).

[0018] However, the partial regions 126 may be arranged in the vertical direction of the reflecting member 110 (i.e., the vertical direction of the mask member 120). In addition, the occupancy rate of the light-transmitting region 122 (or the occupancy rate of the light-shielding region 124) may change continuously in at least one of the width direction and the upper limit direction of the mask member 120.

[0019] Furthermore, two or more partial regions 126 having different light transmittances may be repeatedly provided in the mask member 120. For example, in the mask member 120, first partial regions 126 and second partial regions 126 may be alternately provided.

[0020] FIG. 3 is a diagram for explaining the size of the partial region 126. The mask member 120 is irradiated with light from the measuring device 20 shown in FIG. 1. The width W1 of the partial region 126 is larger than the size W2 (e.g., the width of the footprint) of the light from the measuring device 20 on the mask member 120 (hereinafter, referred to as the light region 200: equivalent to a footprint). For example, as shown in FIG. 3, when the light is irradiated with a half-period shift for each horizontal line, the width W1 of the partial region 126 is preferably 1.5 times or more the size W2 of the light. In other cases (for example, when the irradiation position in the horizontal direction is the same for each line), the width W1 is preferably 2.0 times or more the size W2 of the light. In this way, it is possible to prevent the light from the measuring device 20 from spanning a plurality of partial regions 126 on the mask member 120.

[0021] Furthermore, the width W1 of the partial region 126 is greater than the light irradiation interval (e.g., the center-to-center distance between two adjacent footprints) on the mask member 120. For example, as shown in FIG. 3, when light is irradiated with a half-period shift for each horizontal line, the width W1 is preferably 1.5 times or more the distance between the light irradiations. In other cases (e.g., when the horizontal irradiation position is the same for each line), the width W1 is preferably 2.0 times or more the distance between the light irradiations. In this way, the light can be easily irradiated to each of the multiple partial regions 126.

[0022] 4(A) and 4(B) are diagrams showing a first example of the light-transmitting region 122 and the light-shielding region 124 in the partial region 126. In the example shown in this figure, the light-transmitting region 122 and the light-shielding region 124 are both rectangular (e.g., square) of the same shape. The light-transmitting region 122 and the light-shielding region 124 are both smaller than the light region 200 on the mask member 120. For example, the width of the light-transmitting region 122 and the width of the light-shielding region 124 are both 25% or less of the width of the light region 200 (corresponding to W1 in FIG. 3). The example shown in FIG. 4(A) and the example shown in FIG. 4(B) have different occupancies of the light-transmitting region 122 (i.e., the occupancy of the light-shielding region 124). Specifically, the occupancy of the light-transmitting region 122 in the example shown in FIG. 4(A) is 50%, while the occupancy of the light-transmitting region 122 in the example shown in FIG. 4(B) is 25%. In the example shown in FIG. 4A, the light-transmitting regions 122 and the light-shielding regions 124 are alternately arranged in both the width direction and the height direction, but the layout thereof is not limited to this example.

[0023] 5(A) and 5(B) are diagrams showing a second example of the light-transmitting region 122 and the light-shielding region 124 in the partial region 126, and correspond to FIG. 4(A) and FIG. 4(B), respectively. In the example shown in this figure, the size of the light-transmitting region 122 and the size of the light-shielding region 124 are smaller than those in the example shown in FIG. 4. [0] The mask member 120 using the example shown in FIG. 5 is used when the distance L1 (see FIG. 1) from the measuring device 20 to the reflector 10 is small. This is because the light region 200 becomes smaller as the distance L1 becomes smaller. In other words, it is preferable that the light-transmitting region 122 and the light-shielding region 124 become smaller as the distance L1 becomes smaller. However, this is not the case when the directivity of the irradiated light is sufficiently high.

[0024] 6(A) and 6(B) are diagrams showing a third example of the light-transmitting region 122 and the light-shielding region 124 in the partial region 126, and correspond to FIG. 4(A) and FIG. 4(B), respectively. In the example shown in this figure, the entire mask member 120 is the light-shielding region 124. A plurality of light-transmitting regions 122 are provided in the light-shielding region 124. In the example shown in this figure, the light-transmitting region 122 is circular (or elliptical). As shown in FIG. 6(A), at least one of the plurality of light-transmitting regions 122 may have a different size from the others. Also, as shown in FIG. 6(B), the plurality of light-transmitting regions 122 may all have the same shape.

[0025] 6A, the entire mask member 120 may be the light-transmitting region 122. In this case, a plurality of light-shielding regions 124 are provided in the light-transmitting region 122.

[0026] 7(A) and 7(B) are diagrams showing a third example of the light-transmitting region 122 and the light-shielding region 124 in the partial region 126, and correspond to FIGS. 4(A) and 4(B), respectively. In the example shown in this figure, the light region 200 is not a rectangle but a parallelogram. This is because, for example, when the mask member 120 is flat, the light region 200 is distorted at the end of the mask member 120. The shapes of the light-transmitting region 122 and the light-shielding region 124 are similar to the shape of the light region 200 after distortion.

[0027] Fig. 8 is a diagram showing a modified example of the reflector 10 shown in Fig. 1. In the example shown in this figure, the mask member 120 of the reflector 10 has a light-shielding region 124 only in a part (for example, the center part). In other words, the mask member 120 is provided to reduce the reflectance of a part of the reflecting member 110.

[0028] Fig. 9 is a diagram for explaining the purpose of installing the mask member 120 shown in Fig. 8. When the reflectance of the reflecting member 110 of the reflector 10 is high, as shown in Fig. 9(A), the peak intensity of the reflected light is too strong, and the light receiving unit of the measuring device 20 cannot output an accurate received waveform, and as a result, the peak position (time) of the reflected light cannot be detected. An example of a case where this occurs is when the reflecting surface of the reflecting member 110 is a retroreflective surface and light is irradiated onto an area of ​​the reflecting member 110 located in front of the measuring device 20.

[0029] Even in such a case, if the light-shielding area 124 of the mask member 120 is provided in an area of ​​the reflecting member 110 where the reflectance is too high, the peak position (time) of the reflected light received by the measuring device 20 can be accurately detected, as shown in FIG. 9(B).

[0030] The intensity per unit area of ​​the light emitted from the measuring device 20 when it reaches the reflector 10 decreases as the distance L1 from the measuring device 20 to the reflector 10 increases. For this reason, it is preferable to replace the mask member 120 according to the distance L1. Specifically, it is preferable that the light transmittance of the mask member 120 increases as the distance L1 increases.

[0031] As described above, according to this embodiment, the mask member 120 is provided on the reference reflecting surface of the reflecting member 110. The mask member 120 is replaceable. Therefore, the reflectance of the reflector 10 can be easily changed.

[0032] 2 and 3, the mask member 120 has a plurality of partial regions 126. At least two of the plurality of partial regions 126 have different light transmittances. Therefore, inspections related to a plurality of reflectances can be performed with one reflector 10.

[0033] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. [Explanation of symbols]

[0034] 10 reflector 20 Measuring Equipment 30 Analyzer 110 Reflective material 120 Mask material 122 Translucent area 124 Shading area 126 Partial area 200 light area

Claims

1. A reflector used in inspection of a measuring device that measures a distance to an object by an optical method, a reflecting member having a reference reflecting surface that reflects light irradiated from the measuring device; A plurality of mask members for changing the reflectance of the reflecting member; Equipped with One of the plurality of mask members is overlapped on at least a portion of the reference reflecting surface, thereby preventing at least a portion of the light from reaching the reference reflecting surface, A reflector in which the reflectance of the reflective member is changed by changing one of the mask members.

2. 2. The reflector according to claim 1, The mask member is A light-transmitting region; A plurality of light-shielding regions provided in the light-transmitting region; It has A reflector, wherein the size of the light blocking area is smaller than the size of the light on the mask member.

3. 2. The reflector according to claim 1, The mask member is A light-shielding region; A plurality of light-transmitting regions provided in the light-shielding region; It has A reflector, wherein the size of the light transmitting region is smaller than the size of the light on the mask member.

4. The reflector according to claim 1, At least one of the mask members has a light blocking region and a light transmitting region, A reflector, wherein in any one of the at least one mask members, at least one of the light blocking regions and at least one of the light transmitting regions have the same size as each other.

5. The reflector according to claim 1, At least one of the mask members has a light blocking region and a light transmitting region, A reflector, wherein in any one of the at least one mask members, at least one of the light blocking regions and at least one of the light transmitting regions have sizes different from each other.

6. The reflector according to any one of claims 1 to 5, The mask member is a reflector having a plurality of partial regions each having a different light transmittance.

7. 7. The reflector according to claim 6, A reflector in which the light absorptance changes gradually or stepwise in at least one of the width direction and the vertical direction of the reflective member.

8. 7. The reflector according to claim 6, A reflector in which two or more partial regions having different light transmittances are repeatedly provided in at least one of a width direction and a vertical direction of the reflective member.

9. The reflector according to any one of claims 1 to 8, The one mask member is a reflector that is selected depending on the distance from the measurement device to the reflector.

10. The reflector according to any one of claims 1 to 9, The reference reflecting surface is a Lambertian reflecting surface or a retroreflective surface.

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