Inspection device and inspection light irradiation device

Abstract

The invention provides an inspection light irradiation device (100) which can contribute to miniaturization, output stability, improvement of inspection precision and the like. An inspection light irradiation device (100) is provided with: a plurality of laser light sources (2) attached in a predetermined direction; a reflecting member (3) having a reflecting surface (3a) that diffuses and reflects the laser light (L) emitted from the laser light source (2); and a diffusion member (4) that diffuses and transmits the laser light diffused and reflected by the reflection surface (3) and emits the laser light to the outside, and the laser light source (2) is disposed so as to irradiate the laser light (L) from an oblique direction with respect to the reflection surface (3a). The angle formed by the direction in which the pointing angle of the laser light (L) is wide and the mounting direction of the laser light source (2) is smaller than the angle formed by the direction in which the pointing angle of the laser light (L) is narrow and the mounting direction.

Description

Technical Field

[0001] The present invention relates to an inspection device for inspecting an inspection target surface by irradiating light, and preferably relates to an inspection device for inspecting the inspection target surface by irradiating monochromatic light to generate interference fringes and utilizing the interference fringes to inspect the inspection target surface. Background Art

[0002] As shown in Patent Document 1, a measuring method is known in the past, which generates interference fringes by irradiating a smooth inspection target surface with monochromatic light, and detects the concavity or deformation of the smooth surface based on the disorder of the interference fringes. In addition, the light irradiation device such as the surface emitting type or the line emitting type used to generate such interference fringes requires the monochromaticity of the light.

[0003] Therefore, in such a conventional light irradiation device, for example, multi-wavelength light emitted from a light source such as a mercury lamp is passed through a bandpass filter or the like to generate monochromatic light.

[0004] However, in such a structure, since most of the light emitted from the light source is cut off, the light utilization efficiency is poor. In order to ensure the output required as a light irradiation device, the output of the light source is increased, and corresponding heat dissipation performance is required, which will cause the lighting device to be correspondingly larger or the price to be correspondingly higher.

[0005] Nevertheless, in the case of a configuration in which a relatively monochromatic LED is used as a light source and a bandpass filter is used to cut off light of unnecessary wavelengths, although the light utilization efficiency is indeed improved compared to the above-mentioned multi-wavelength light source, since the peak wavelength of the LED shifts with temperature, the amount of light per unit time passing through the bandpass filter varies depending on the temperature, and the output may vary significantly.

[0006] In addition, if a laser such as a semiconductor laser is used as a light source, the light source itself becomes an ideal monochromatic light for interference fringe inspection, so there is no need to cut off unnecessary light with a bandpass filter, etc. However, due to the influence of speckle, bright spots other than interference fringes are generated on the surface of the inspection object, resulting in a problem of reduced inspection accuracy. Prior art literature Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-16552 Summary of the invention Problem that the invention aims to solve

[0008] Therefore, the present invention is made to solve the above-mentioned problems at one stroke, and a main object of the present invention is to provide an inspection device that can contribute to miniaturization, output stability, improvement of inspection accuracy, etc. Technical means of solving problems

[0009] That is, the inspection device of the present invention is characterized in that it comprises: a plurality of laser light sources which are installed in an array along a prescribed direction; a reflecting component which is arranged on the optical path of the laser light emitted from the laser light source and has a reflecting surface which diffuses and reflects the irradiated laser light; and a diffusing component which is arranged on the optical path of the laser light diffusely reflected by the reflecting surface and diffuses and transmits the irradiated laser light onto the inspection object surface, the laser light source being arranged to irradiate the laser light from an oblique direction relative to the reflecting surface, and being arranged so that the angle formed by the direction in which the laser light is directed at a wide angle and the installation direction of the laser light source is smaller than the angle formed by the direction in which the laser light is directed at a narrow angle and the installation direction. Effects of the Invention

[0010] According to the present invention thus constituted, in the inspection device, it is possible to achieve miniaturization, output stability, price reduction, improvement in inspection accuracy, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view showing the internal structure of the inspection light irradiation device according to one embodiment. Figure 2 It is a cross-sectional view of the inspection light irradiation device according to this embodiment. Figure 3 It is a perspective view showing the directivity angle of laser light emitted from the laser light source used in this embodiment. Figure 4 It is a perspective view showing the laser beam irradiated onto the reflecting surface in this embodiment. Figure 5 This is a perspective view showing a laser beam irradiated onto a reflecting surface in another embodiment. Figure 6 It is a cross-sectional view of an inspection light irradiation device according to another embodiment. Figure 7 It is a schematic diagram of an inspection light irradiation device according to another embodiment. Figure 8 This is a schematic diagram of an inspection light irradiation device according to another embodiment as viewed from a plane direction. DETAILED DESCRIPTION

[0012] An embodiment of the inspection device of the present invention will be described below with reference to the drawings.

[0013] The inspection device of this embodiment (hereinafter also referred to as the inspection light irradiation device 100) is a surface emitting device that irradiates a single-wavelength inspection light onto an inspection object such as a transparent film or a transparent surface layer, and is used to inspect the deformation or thickness of the surface of the inspection object through the interference fringes generated by the irradiation.

[0014] Hereinafter, the inspection light irradiation device 100 will be described in detail.

[0015] like Figure 1 , Figure 2 As shown, the inspection light irradiation device 100 includes a housing 1 in a rectangular parallelepiped shape, a plurality of laser light sources 2 held or formed on the housing 1 , a reflecting member 3 , and a diffusing member 4 .

[0016] The housing 1 is a hollow member having a bottom plate 11, a top plate 12, a front plate 13, a back plate 14, and left and right side plates 15. In addition, for the sake of convenience, the normal direction of the bottom plate 11 (or the top plate 12) is referred to as the Z direction or the height direction, the normal direction of the side plate 15 is referred to as the X direction or the left and right direction, and the normal direction of the front plate 13 (or the back plate 14) is referred to as the Y direction or the depth direction.

[0017] Here, a semiconductor laser sealed in a can package is used as the laser light source 2. Figure 3 As shown, the laser light L emitted from the laser light source 2 has the following light distribution characteristics: when cut by a plane perpendicular to the central axis of the light (hereinafter referred to as the light axis C), the cross-sectional shape of the light is not a circle, but an ellipse, for example. The laser light L in this example is perpendicular to the direction with the widest pointing angle and the direction with the narrowest pointing angle in the cross section of the light.

[0018] like Figure 1 As shown in FIG. 1 , the laser light sources 2 are installed in series at a certain interval along the length direction of the long substrate 21. In addition, regarding the configuration rotation angle of each laser light source 2 around the light axis C, as shown in FIG. Figure 4 As shown, the arrangement rotation angle of each laser light source 2 is set so that the mounting direction (the length direction of the substrate 21) and the direction of the directivity angle width of each laser light L coincide with each other.

[0019] Furthermore, the substrate 21 on which the laser light sources 2 are mounted is held just above one side of the bottom plate 11, that is, on the front plate 13 of the housing 1. Figure 1 , Figure 2 As shown, a receiving groove 5 extending along the X direction is formed on the inner surface of the front plate 13 , and the substrate 21 is held in the receiving groove 5 so that the length direction of the substrate 21 is consistent with the X direction.

[0020] like Figure 2 As shown in FIG. 1 , the substrate 21 is held in a tilted posture relative to the Z direction, whereby the laser light source 2 is also tilted, and the light axis C of the laser L is set to pass through the opening 5a of the storage groove 5 and obliquely intersect the inner surface of the bottom plate 11. Figure 1 , Figure 2As shown, the position and tilt angle of the laser light source 2 are set so that the maximum length of the irradiation area of ​​the laser light L on the reflecting surface 3a in the Y direction extends over a part or the entire reflecting surface 3a.

[0021] The reflecting member 3 is in the shape of a rectangular plate of equal thickness, and the bottom plate 11 of the housing 1 plays its role. A reflecting surface 3a is formed on the inner surface of the reflecting member 3 (bottom plate 11) by machining or coating. The reflecting surface 3a has the characteristic of diffusely reflecting the incident laser L with the same reflectivity. In addition, the radiation brightness of the light L2 diffusely reflected by the reflecting surface 3a in each direction has the following diffuse reflection characteristics: in the cross section including the central axis of the laser L and the normal line of the reflecting surface 3a, the maximum value of the radiation brightness of the light L2 with a reflection angle of -89° to 89° is less than 550% relative to the radiation brightness of the light L2 with a reflection angle of 0°.

[0022] The diffusion member 4 is in the shape of a rectangular plate of a certain thickness located just above the reflection surface 3a, and is embedded in a window 12a extending in the longitudinal direction provided on the top plate 12. In the diffusion member 4, the surface exposed in the window 12a serves as a light emitting surface.

[0023] Furthermore, in this embodiment, the back plate 14 located on the opposite side of the front plate 13 holding the laser light source 2 across the reflection surface 3a assumes the function of the second reflection member 7, and a second reflection surface 7a is formed on its inner surface. The second reflection surface 7a may have the same reflection characteristics as the reflection surface 3a, or may have a reflection characteristic different therefrom, such as a reflection characteristic of a mirror surface that does not perform diffuse reflection.

[0024] In such a configuration, if the laser light source 2 is turned on, Figure 4 As shown, the laser light L emitted from each laser light source 2 is irradiated onto the reflecting surface 3a without overlapping each other and is diffusely reflected. The diffused reflected light L2 is directly reflected or reflected by the second reflecting surface 7a, and reaches the diffusion component 4 arranged above it, where it is further diffused and transmitted to irradiate the inspection object surface located outside (not shown). As a result, interference fringes are generated on the inspection target surface, and the irregularities or deformation of the inspection target surface are detected based on the form of the interference fringes.

[0025] In the drawings used in the following description, the same reference numerals are given to the components corresponding to those in the above-described embodiment.

[0026] For example, the direction of the wide laser directional angle and the installation direction of the laser light source do not necessarily have to be consistent, and can also be configured so that the angle they form is smaller than the angle formed by the direction of the narrow laser directional angle and the installation direction.

[0027] In the embodiment, the configuration rotation angle of each laser light source around the light axis is set in such a way that the direction of the angular width of all lasers is consistent, but the configuration rotation angle of some laser light sources can also be different. For example, compared with other laser light sources, the configuration rotation angle of one or more laser light sources at both ends can also be determined in such a way that the direction of their angular width is a large angle (such as a right angle) relative to the installation direction, and the configuration interval is set to be smaller. At the two ends of the reflection surface in the X direction, the irradiation intensity of the laser tends to decrease, but this can be prevented by the above-mentioned structure, and the uniformity of the light-emitting surface of the inspection light irradiation device can be further improved.

[0028] The second reflecting surface may also be provided on other inner surfaces of the housing. For example, the second reflecting surface may also be formed on all or part of the inner surfaces of the side panels and the inner surface of the front panel except for the storage groove.

[0029] The tilt angles of the laser beams do not have to be uniform across the board, and may be partially different. Figure 5 In the embodiment shown, two laser light sources 2 and 2' with different tilt angles are arranged alternately. With such a structure, it is also possible to cope with the reflection surface 3a that is long in the Y direction. In this sense, multiple rows of laser light sources can also be arranged in the Z direction. In addition, as shown in the figure, the laser beams L may overlap on the reflection surface 3a.

[0030] like Figure 6 As shown, the laser light sources 2 may be disposed at both ends of the reflecting surface 3 a in the Y direction.

[0031] like Figure 7 As shown, a transmissive member 3A may be used instead of a reflective member. In this case, the laser light source 2 is also irradiated from an oblique direction. The transmissive member 3A diffuses and transmits the laser light L, and the laser light L may be diffused on its surface or back surface, or by a filler or the like provided inside.

[0032] The reflecting surface or the diffusing member may be not only rectangular or square, but also circular or elliptical. Figure 8 As shown, the laser light sources 2 can be arranged in a circular or elliptical shape when viewed from above. In this case, the installation direction is the tangent direction of the arrangement trajectory S such as the circle or the ellipse.

[0033] In order to irradiate the laser beam obliquely with respect to the reflecting surface, the laser beam may be reflected by a reflecting mirror or the like instead of being arranged in an inclined posture.

[0034] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

[0035] The features of the inspection light irradiation device according to the present embodiment described above are summarized as follows.

[0036] [1] The inspection device or the inspection light irradiation device comprises: a plurality of laser light sources installed along a predetermined direction; a reflective member arranged on the optical path of the laser light emitted from the laser light source, and having a reflective surface for diffusing and reflecting the irradiated laser light; and a diffusing member arranged on the optical path of the laser light diffusely reflected by the reflective surface, and diffusing and transmitting the irradiated laser light to the outside, wherein the laser light source is arranged to irradiate the laser light from an oblique direction relative to the reflective surface, and is arranged such that the angle formed by the direction of the wide angular direction of the laser light and the installation direction of the laser light source is smaller than the angle formed by the direction of the narrow angular direction of the laser light and the installation direction.

[0037] With such a structure, the following effects can be achieved.

[0038] Since the laser light emitted from the laser light source is emitted through the reflective member and the diffusion member, the speckle noise can be reduced, for example, as close to 0 as possible. The reason is that the speckle noise decreases in inverse proportion to the square root of the number of light sources, but by passing through the diffusion member and the reflective member, it is possible to approach a state where there are countless light sources. As a result, the inspection accuracy can be improved.

[0039] Since the laser light is irradiated obliquely with respect to the reflection surface, the irradiation area is larger than when the laser light is irradiated vertically, which also contributes to reducing the speckle noise.

[0040] The light utilization efficiency of laser light sources is superior to other light sources, and since no optical filter is required, energy loss can be suppressed, for example, the heat dissipation function can be controlled to a minimum or the number of components can be reduced, resulting in a simplified structure and a smaller device. In addition, since no optical filter is used, the output change depends only on the laser light source, and by using a semiconductor laser or the like as the laser light source, sufficient output stability can be ensured.

[0041] The fact that the laser is irradiated obliquely toward the reflective member also contributes to the miniaturization of the device. This is because, compared with the case of vertical irradiation, even if the laser light source is brought close to the reflective member, the irradiation area of ​​the laser at the reflective member can be expanded, and the uniformity of the brightness of the light emitting surface can be ensured.

[0042] Since each laser light source is arranged in a manner that the direction of the laser's wide angle of orientation (the direction of the light distribution width) is consistent with the mounting direction, compared with other cases (for example, the case where the laser light source is arranged in a manner that the direction of the narrow angle of orientation is consistent with the mounting direction), even if the interval between the laser light sources is lengthened, the irradiation range of each laser on the reflection surface can be made continuous without interruption, or even if it is interrupted, the interval can be narrowed, and the uniformity of the light emitted from the light irradiation device can be ensured. In addition, since the laser is irradiated obliquely relative to the reflection surface, the irradiation area in the direction perpendicular to the mounting direction, that is, the Y direction, can be fully expanded.

[0043] [2] In the inspection device or inspection light irradiation device according to the configuration of [1], the reflecting surface has the following characteristics: it has the same light reflectivity, and in a cross section including the central axis of the laser and the normal to the reflecting surface, in the light diffusely reflected by the reflecting surface, the maximum value of the radiant brightness of light with a reflection angle of -89° to 89° is less than the ratio of the radiant brightness of light with a reflection angle of 0° to 550%.

[0044] With such a structure, the laser light diffusely reflected by the reflecting surface can be irradiated onto the diffusion member more efficiently and uniformly, and high-quality surface light emission can be ensured.

[0045] [3] In the inspection device or inspection light irradiation device according to the configuration of [1] or [2], the laser light source is arranged between the diffusion member and the reflection member, and is arranged outside the light emitting surface of the diffusion member when viewed from the normal direction of the diffusion member.

[0046] With such a configuration, since the laser light source avoids the optical path of the laser light traveling from the reflective member to the diffuser member, it is possible to prevent light loss.

[0047] [4] In the inspection device or inspection light irradiation device, in the configuration of [1], [2] or [3], the reflecting member and the diffusing member are arranged relative to each other, and a second reflecting member is provided on one side of the reflecting member, the second reflecting member has a second reflecting surface vertically rising toward the diffusing member, and the laser is irradiated from the other side of the reflecting member.

[0048] According to such a structure, among the laser beams diffusely reflected by the reflection surface, the laser beams that do not directly travel toward the diffusion member are also reflected by the second reflection surface and reach the diffusion member, so that the light utilization efficiency is improved.

[0049] [5] The inspection device or inspection light irradiation device, in the configuration of [1], [2], [3] or [4], further comprises a shell, which is in the shape of a rectangular parallelepiped and has a bottom plate, a top plate opposite to the bottom plate, a front plate, a back plate and left and right side plates, the reflecting member is the bottom plate or is mounted on the inner surface of the bottom plate, the diffusing member is the top plate or is mounted on a window provided on the top plate, and the laser light source is mounted in the left-right direction and is retained in a storage groove opened on the inner surface of the front plate.

[0050] With such a structure, the present invention can be realized with a simple configuration.

[0051] [6] Another embodiment of an inspection device or an inspection lighting device comprises: a plurality of laser light sources arranged in a manner along a predetermined direction; a transmissive member disposed on an optical path of laser light emitted from the laser light source to diffuse and transmit the laser light; and a diffusing member disposed on an optical path of laser light diffused and transmitted by the transmissive member to diffuse and transmit the laser light to the outside, wherein the laser light source is configured to irradiate the laser light from an oblique direction relative to a surface of the transmissive member, and is configured such that an angle formed by a direction having a wide directivity angle of the laser light and the installation direction of the laser light source is smaller than an angle formed by a direction having a narrow directivity angle of the laser light and the installation direction. The same effect can be achieved by using a transmissive member instead of a reflective member. Possibility of industrial application

[0052] It is possible to provide an interference fringe inspection device that can contribute to miniaturization, output stability, improvement of inspection accuracy, etc. Explanation of symbols

[0053] 100…Inspection light irradiation device (inspection device) 2…Laser light source L…Laser 3…Reflective member 3a…Reflective surface 4…Diffusion member 7…Second reflecting member 7a…Second reflecting surface 1…Housing 11…Base Plate 12…Top Plate 12a…Window 13…Front panel 14…Back panel 15…left and right side panels.

Claims

1. An inspection device, characterized in that: have: A plurality of laser light sources are installed in an array along a predetermined direction; A reflecting member disposed on an optical path of laser light emitted from the laser light source and having a reflecting surface for diffusing and reflecting the laser light; as well as a diffusion member disposed on an optical path of the laser beam diffusely reflected by the reflection surface, so as to diffusely transmit the laser beam and irradiate the inspection object surface; The laser light source is configured to irradiate laser light from an oblique direction relative to the reflecting surface, and is configured so that the angle between the direction with a wide laser direction angle and the installation direction of the laser light source is smaller than the angle between the direction with a narrow laser direction angle and the installation direction.

2. The inspection device according to claim 1, characterized in that: The reflecting surface has the following characteristics: it has the same light reflectivity, and in a cross section containing the central axis of the laser and the normal to the reflecting surface, the ratio of the maximum value of the radiant brightness of light with a reflection angle of -89° to 89° among the light diffusely reflected by the reflecting surface to the radiant brightness of light with a reflection angle of 0° is less than 550%.

3. The inspection device according to claim 1, characterized in that: The laser light source is disposed between the diffusion member and the reflection member, and is disposed outside a light emitting surface of the diffusion member when viewed in a normal direction of the diffusion member.

4. The inspection device according to claim 1, characterized in that: The reflecting member and the diffusing member are arranged opposite to each other. The second reflecting member is provided on one side of the reflecting member, and the second reflecting member has a second reflecting surface vertically standing toward the diffusing member. The laser light is irradiated from the other side of the reflective member.

5. The inspection device according to claim 1, characterized in that: The device further comprises a housing, which is in a rectangular parallelepiped shape and comprises a bottom plate, a top plate opposite to the bottom plate, a front plate, a back plate, and left and right side plates. The reflective member is the bottom plate, or is mounted on the inner surface of the bottom plate, The diffusion member is the top plate, or is mounted on a window provided on the top plate, The laser light source is installed in the left-right direction and is held in a storage groove opened on the inner surface of the front panel.

6. An inspection device, characterized in that: have: A plurality of laser light sources are installed in an array along a predetermined direction; A transmission member disposed on an optical path of laser light emitted from the laser light source and allowing the laser light to diffuse and transmit therethrough; as well as a diffusion member disposed on an optical path of the laser beam diffused and transmitted by the transmission member, so as to diffuse and transmit the laser beam and irradiate the inspection target surface; The laser light source is configured to irradiate laser light from an oblique direction relative to the surface of the transparent component, and is configured so that the angle between the direction with a wide laser direction angle and the installation direction of the laser light source is smaller than the angle between the direction with a narrow laser direction angle and the installation direction.

7. A light irradiation device for inspection, characterized in that: have: A plurality of laser light sources are installed in an array along a predetermined direction; A reflecting member disposed on an optical path of laser light emitted from the laser light source and having a reflecting surface for diffusing and reflecting the laser light; a diffusion member disposed on an optical path of the laser beam diffusely reflected by the reflection surface, so as to diffusely transmit the laser beam and emit it to the outside; The laser light source is configured to irradiate laser light from an oblique direction relative to the reflecting surface, and is configured so that the angle between the direction with a wide laser direction angle and the installation direction of the laser light source is smaller than the angle between the direction with a narrow laser direction angle and the installation direction.

8. A light irradiation device for inspection, characterized in that: have: A plurality of laser light sources are installed in an array along a predetermined direction; A transmission member disposed on an optical path of laser light emitted from the laser light source and allowing the laser light to diffuse and transmit therethrough; as well as a diffusion member disposed on an optical path of the laser beam diffused and transmitted by the transmission member, so as to diffuse and transmit the laser beam and emit it to the outside; The laser light source is configured to irradiate laser light from an oblique direction relative to the surface of the transparent component, and is configured so that the angle between the direction with a wide laser direction angle and the installation direction of the laser light source is smaller than the angle between the direction with a narrow laser direction angle and the installation direction.

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