Inspection device and inspection method for surface of solar panel protective glass

Abstract

To provide an inspection device and an inspection method suitable for inspecting scratches and foreign matters on a protective glass surface of a solar panel surface.SOLUTION: An inspection device for a surface of protective glass of a solar panel including a solar cell and protective glass for protecting the solar cell comprises: an irradiation optical system which has a light source and a polarizer which polarizes light from the light source and irradiates the protective glass with the light; and a detection optical system which detects light reflected by the protective glass. The detection optical system has at least a lens, a polarizer, a pinhole, and a photodetector, and is arranged on an optical path in this order. At the time of surface inspection, the lens is installed such that an imaging position of the protective glass surface is on the surface of the pinhole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to inspection of scratches and foreign matter on the surface of a transparent member, and more particularly to an inspection device and method for inspecting the surface of a protective glass for a solar panel. [Background technology]

[0002] In order to achieve a sustainable society, the large-scale introduction of solar power generation as a renewable energy source is progressing, but at the same time, the disposal of solar panels after use is becoming an issue, and there is an increasing need for technologies to reuse components.

[0003] Solar panels are mainly composed of a metal frame, solar cells, and protective glass to protect the solar cells, with the protective glass glued onto the solar cells. Currently, only a portion of these components are reused, and the protective glass in particular is often crushed and then disposed of in landfills. One of the reasons why crushed glass is not reused and is disposed of in landfills is that the price of crushed glass (cullet) is low and does not justify the cost of recycling. In response to this issue, technology has been developed to extract high-quality glass sheets from solar panels without crushing them, and it is becoming possible to sell used glass at a price that is commensurate with the cost of recycling.

[0004] However, when solar panels are installed outdoors and exposed to wind, rain, and snow, there is a possibility that the glass on the surface may become scratched, chipped, or have foreign matter attached to it. In the following, such undesirable areas of deterioration will be collectively referred to as defects. The number and location of such defects will vary depending on the usage environment and individual products, so it is necessary to inspect them and change the treatment method depending on the results.

[0005] For example, if it is determined that there are only a few scratches, it can be reused for furniture or aquariums that require aesthetics. If it is determined that there are many scratches and it cannot be reused, it can be used as frosted glass for building materials or for greenhouses where even fine scratches are not noticeable. If there are too many scratches to reuse, it can be crushed and disposed of as usual.

[0006] One possible method for inspecting the surface of the protective glass of such solar panels for scratches and chips is to use, for example, a technique for inspecting the surface of semiconductor wafers for scratches and defects. Patent Document 1 describes a semiconductor wafer inspection method in which a laser beam is irradiated onto the semiconductor wafer, and the laser beam is scattered at the scratched or defective portion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2010-14635 A Summary of the Invention [Problem to be solved by the invention]

[0008] Defects in glass on solar panels are thought to occur mainly on the surface exposed to wind and rain, so it is necessary to selectively inspect the vicinity of the glass surface, rather than the inside of the glass or the back side. However, since the glass on solar panels has structures such as solar cell electrodes on the back side, there is a concern that defects may be erroneously detected due to light reflected by the electrodes, if the technology described in Patent Document 1 is adapted for use. In addition, if the solar cell is polycrystalline silicon, there is a possibility that scattered light at the crystal grain boundaries of silicon may be erroneously detected as scattered light from glass defects.

[0009] An object of the present disclosure is to provide an inspection device and an inspection method suitable for inspecting the surface of a protective glass on a solar panel for scratches and foreign matter. [Means for solving the problem]

[0010] An inspection method according to one embodiment of the present disclosure is as follows.

[0011] A surface inspection device for protective glass for solar panels having a solar cell and a protective glass for protecting the solar cell, the device comprising: an irradiation optical system having the light source and a polarizer that polarizes light from the light source, which irradiates light onto the protective glass; and a detection optical system that detects light reflected by the protective glass, the detection optical system having at least a lens, a polarizer, a pinhole, and a photodetector, which are arranged in this order on an optical path, and the lens is positioned so that, during surface inspection, the position where the image of the protective glass surface is formed is on the plane of the pinhole. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide an inspection device and an inspection method suitable for inspecting scratches and foreign matter on the surface of a protective glass on a solar panel. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of an inspection device and a solar panel. [Diagram 2] 4A and 4B are diagrams for explaining the relationship between the distance between optical elements of a detection optical system and the focal length. [Diagram 3] 11 is a flowchart illustrating an inspection procedure. [Figure 4] 1 is a diagram for defining the angle of incidence of an irradiation optical system. [Figure 5A] FIG. 13 is a diagram of an inspection device according to a modified example. [Figure 5B] 13 is a conceptual diagram of irradiated light and detected light in an inspection device according to a modified example. [Figure 6] 10 is a flowchart illustrating an inspection procedure in a modified example. [Figure 7A] FIG. 13 is a diagram of an inspection device according to a modified example. [Figure 7B] FIG. 13 is a conceptual diagram of an irradiation light source in an inspection device according to a modified example. [Figure 8] FIG. 13 is a diagram of an inspection device according to a modified example. [Figure 9]10 is a flowchart illustrating an inspection procedure in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the contents of the present disclosure are not limited to the embodiments described below, and various modifications are possible within the scope of the technical concept. In addition, the corresponding parts in each drawing used in the description of each embodiment described below are indicated by the same reference numerals, and duplicated descriptions will be omitted.

[0015] In this embodiment, an example of inspecting the glass on the surface of a solar panel will be described, but the target object is not limited to a solar panel. For example, glass used on the outside of a refrigerator can also be inspected because an opaque material is used on the back side. EXAMPLES

[0016] FIG. 1 is a schematic diagram showing the configuration of an inspection device used in the inspection method of this embodiment.

[0017] The inspection object 1 is composed of a transparent member (glass plate) 1a on the front side and an opaque member 1b consisting of a solar cell and a metal frame on the back side. The inspection device is composed of an irradiation optical system 2 that irradiates light L1, a detection optical system 3 that detects light L2 emitted from a defective portion, and a stage 4 that moves the inspection object 1.

[0018] The irradiation optical system 2 is composed of a light source 2a, a lens 2b, and a polarizer 2c. The light source 2a may be a white light source such as an LED or a lamp, or a laser light source that emits light of a single wavelength. In the case of a laser, it may be a continuous wave laser or a pulsed laser. Alternatively, it may be a white laser light source such as a supercontinuum light.

[0019] The glass to be inspected is transparent (there is no specific wavelength that absorbs / reflects light) to a wide range of wavelengths from ultraviolet to infrared, so a light source of any wavelength can be used, but with visible light, the position of the light irradiation can be confirmed visually, making it easy to adjust the device. Also, as will be described later, in the case of visible light, inexpensive CCD or C-MOS sensors and Si photodiodes used in cameras can be used for the sensors used in the detection optical system, reducing the cost of the entire device.

[0020] Furthermore, visible light has a wavelength that is highly absorbed by the solar panel on the back side, so the reflectance from the back side is low, making it less likely to cause false detection. Among visible light, blue light is preferable because it has a short wavelength and can detect finer defects. Blue light is light with a wavelength of approximately 430nm to 490nm.

[0021] Lens 2b is used to irradiate the light emitted from the light source onto the inspection area of ​​the sample. For example, as shown in Figure 1, it is sufficient to convert the light into parallel light and then irradiate a wide area. Irradiating a wide area makes the system robust against misalignment of the optical axis, and reduces the number of regular optical axis adjustments.

[0022] Alternatively, if it is desired to inspect a narrower area in detail, multiple lenses may be used to focus the light on the inspection object. When a generally used circular lens is used, the light is irradiated onto a circular or elliptical area depending on the angle of incidence, but it is also possible to irradiate the light in a line shape by using a cylindrical lens. An example of using a cylindrical lens will be described in detail in the modified example.

[0023] The polarizer 2c is used to adjust the polarization plane of the light irradiated to the inspection object. When the light source is a non-polarized light source such as an LED, a polarizer can be used as the polarizer, and when the light source is a laser, a wave plate for rotating the polarization plane can be used.

[0024] The direction of polarization can be set arbitrarily, but in order to increase the reflectance on the surface of the transparent member and reduce the amount of light transmitted inside the transparent member, it is more preferable to set the polarization plane to s-polarization. Note that when using a laser light source that outputs linearly polarized light, if the polarization plane is fixed to s-polarization, polarizer 2c may be omitted.

[0025] The detection optical system 3 is composed of lenses 3a and 3a', a variable aperture 3b, a polarizer 3c, a pinhole 3d, and a light receiving element 3e. Light L2 generated from a defect site passes through the lens 3a, the variable aperture 3b, the polarizer 3c, the lens 3a', and the pinhole 3d in that order, and is detected by the light receiving element 3e.

[0026] The detection optical system 3 is configured to selectively detect only light from defective sites near the surface of the inspection target, and combines a confocal configuration with filtering by a polarizer.

[0027] First, the confocal configuration will be described. The confocal configuration is composed of a lens 3a, a variable aperture 3b, a lens 3a', and a pinhole 3d. Confocal is a method that can selectively detect only the light emitted from the focal position of the lens 3a by projecting the focal point of the lens 3a onto the pinhole 3d and detecting only the light that has passed through the pinhole. In other words, the detection optical system of this embodiment is an optical system with a shallow depth of field that visualizes only the vicinity of the surface of the inspection target.

[0028] The positional relationship of each component required to achieve such a confocal configuration will be explained using Figure 2. For the sake of explanation, the focal length of lens 3a is assumed to be f, and the focal length of lens 3a' is assumed to be f'. In this case, the distance between lens 3a and the surface of transparent member 1a is adjusted to be f. Since the light between lenses 3a and 3a' is parallel, the distance can be set arbitrarily, but it is preferable to make it as short as possible, as this makes adjustment easier and makes the device more compact. The distance between lens 3a' and pinhole 3d is assumed to be f'.

[0029] To selectively inspect only defective areas near the surface, the relationship between the depth of field of the entire optical system and the thickness of the transparent member is important. For example, even in a confocal optical system, if the depth of field is deep, light generated from outside the focus passes through a pinhole, and the selectivity expected in this embodiment cannot be obtained, so an adjustment to make the depth of field shallower is necessary.

[0030] The depth of field in a confocal configuration is approximately ±0.7λ / NA from the focal position, although this varies slightly depending on the definition, where NA is the numerical aperture of the optical system and λ is the wavelength. 2 Therefore, to make the depth of field shallower, we should increase the NA. NA can be written as NA=sinα, where α is the divergence angle of the light beam in Figure 2. Now, α=tan -1 Since (D / 2f), the aforementioned adjustment to make the depth of field shallower can be achieved by adjusting D or f.

[0031] In the first embodiment, the NA is adjusted by using the variable aperture 3b. However, it is also possible to use a composite lens made up of a plurality of lenses as the lens 3a and adjust the focal length f.

[0032] Next, a filtering method using polarizer 3c will be described. Light scattered at a defect site is repeatedly diffusely reflected at the interface with the glass and then emitted, and is characterized by changing into a different polarization plane from the light reflected on a smooth surface. Therefore, if the polarizer is adjusted to transmit light at an angle of 90 degrees to the polarization plane of the incident light, it is possible to extract only the polarized component changed at the defect site. For example, if the polarization of the incident light is s-polarized, it is recommended to adjust the polarizer to the direction of p-polarized light. By detecting only a specific polarization plane in this way, the difference between the defect site and the smooth surface can be detected more clearly, which has the effect of enabling highly sensitive inspection.

[0033] The polarizer 3c is inserted between the lenses 3a and 3a'. In this configuration, the light between the lenses 3a and 3a' is parallel, so the focus does not change even if a polarizer is inserted, resulting in a clearer image. The polarizer 3c and the variable aperture 3b may be arranged in any order, but it is preferable to arrange the variable aperture 3b on the lens 3a side, as this allows for more robust inspection against noise caused by stray light, etc.

[0034] The light receiving element 3e may be a light receiving element such as a Si photodiode. A Si photodiode is preferable because it has sufficient sensitivity in the visible light wavelength range targeted in this embodiment and can be realized at low cost.

[0035] The stage 4 is a movable stage used to move the inspection range of the object to be inspected within the XY plane.

[0036] The inspection method in this embodiment will be described with reference to the flow chart shown in FIG.

[0037] First, an object to be inspected is placed on the stage (S1). Next, the angle of incidence of the first light is set (S2). The angle of incidence is the angle θi with respect to the vertical direction (Z direction) of the surface of the object to be inspected, as shown in Fig. 4. As explained as the problem to be solved by the present invention, when light passes through the surface and reaches the back surface, the possibility of false detection of defective parts increases due to scattered light or reflected light from solar cell wiring on the back surface. Therefore, it is preferable to adjust the angle of incidence so that the transmittance is as low as possible (the reflectance is high). A large angle of incidence θi is desirable because it increases the reflectance on the surface.

[0038] Specifically, it is preferably 50 degrees to 85 degrees. When the incident angle is smaller than 50 degrees, since more than 90% of the light passes through the surface, there is a high possibility of misdetecting defective sites due to scattered light or reflected light from the solar cell wiring on the back surface described above. On the other hand, when the incident angle approaches 90 degrees, the irradiation optical system becomes almost parallel to the measurement object, making installation difficult. Therefore, it is desirable that the incident angle is smaller than 85 degrees. Furthermore, when the incident angle is between 80 degrees and 85 degrees, the reflectance on the surface can be 50% or more, which is more preferable.

[0039] Subsequently, focus adjustment is performed (S3). As already explained, since the detection optical system has a confocal configuration, the light generated at the focal position of lens 3a is selectively detected. Therefore, the distance between the detection optical system and the inspection object is adjusted so that the surface of the transparent member comes to the focal point of lens 3a. The distance can be adjusted by moving the entire optical system or by moving only lens 3a. Alternatively, the stage 4 may be a three-axis stage movable in the XYZ directions, and adjusted by moving it in the Z-axis direction.

[0040] Next, the numerical aperture is adjusted and the depth of field is set to an appropriate value (S4). When the depth of field is made shallower, it becomes easier to distinguish from scattered light from the solar cell adhered to the back surface of the glass. However, conversely, if it is made too shallow, there will be a problem that it becomes difficult to detect deep scratches on the surface. Therefore, there is an optimal value for the depth of the depth of field according to the thickness t of the transparent member.

[0041] In particular, within the range satisfying 0.7λ / NA 2 < t, it is advisable to adjust so that the NA becomes as low as possible (so that the depth of field becomes deeper). In this embodiment, since the NA is adjusted by a variable aperture, adjusting the numerical aperture specifically means adjusting the variable aperture.

[0042] Once the optical system adjustment is complete, actual measurement is performed. Measurement involves moving the stage (S5), measuring the signal level (S6), and if the measured signal level is equal to or greater than the set threshold, recording the coordinates (x, y) at that time (S7, S8). Once the measurement of the entire measurement target is complete, the measurement is completed and the inspection target is removed (S10).

[0043] In this embodiment, only the coordinates exceeding the specified threshold are recorded, and only the position distribution of the defect portion is output, but it is also possible to simply obtain the signal amount as a function of the coordinates (x, y), and finally output a monochrome image corresponding to the signal intensity. When a monochrome image is output, the type, shape, and size of the defect can be analyzed by image processing, pattern recognition, etc., and it is possible to more accurately determine whether the glass can be reused and where it should be reused. EXAMPLES

[0044] The second embodiment differs from the first embodiment mainly in that the stage 4 is constituted by a belt conveyor 4'.

[0045] An example of an inspection device used in this embodiment will be described with reference to FIGS. 5A and 5B. Fig. 5A is a cross-sectional view of the inspection device used in this modification. Fig. 5B is a top view of the light irradiation area L1a and the inspection area L2a in this modification. The basic configuration is the same as in the first embodiment, so only the differences will be described.

[0046] A composite member is placed on a belt conveyor 4' as the inspection object 1, and the belt conveyor can move the inspection object in the X-axis direction. The irradiation optical system irradiates a linear irradiation range L1a parallel to the Y-axis. For example, if a line generator lens is used for the lens 2b', light can be irradiated on a line at once. In this way, an optical system using a line generator lens does not require the addition of a moving mechanism, and therefore has the effect of reducing the influence of vibrations caused by the moving mechanism.

[0047] However, when a line generator is used, the amount of light irradiated per unit area decreases, and the amount of signal obtained may be insufficient. In such a case, a movable mechanism for moving the irradiation optical system in the Y-axis direction or a mechanism for scanning the irradiation position in the Y-axis direction using a mirror may be additionally provided to irradiate light in a spot shape as in the first embodiment.

[0048] The detection optical system is additionally provided with a movable mirror 3f on the optical path, and the Y coordinate of the object to be inspected, which is imaged on the pinhole, moves according to the angle of the movable mirror, so that the position detection position of the inspection area L2a can be scanned in the Y direction. When a movable mirror is used, a high-speed galvano scanner or the like can be used, which has the effect of enabling high-speed inspection.

[0049] For example, it is possible to scan the inspection range in the Y direction while moving the belt conveyor at a constant speed, thereby shortening the overall inspection time. Alternatively, the entire optical system may be scanned in the Y-axis direction without adding the movable mirror 3f.

[0050] An inspection device used in such an example is shown in Figures 7A and 7B. Figure 7A is a cross-sectional view of the inspection device in the XZ plane, and Figure 7B is a cross-sectional view of the inspection device in the YZ plane. In the example of Fig. 7, the detection optical system 3 is fixed to a movable mechanism 6 in the Y-axis direction, and the entire detection optical system 3 moves in response to the movement of the movable mechanism. This makes it possible to scan the detection range in the Y-axis direction. When a movable mirror is used, the size of the composite material that can be inspected is limited by the movable range of the mirror and the diameter of the lens, but using a movable stage eliminates these limitations and is therefore more suitable for inspecting large items such as solar panels.

[0051] The inspection procedure in the second embodiment will be described with reference to FIG. 6. Steps S1 to S4 are the same as those in the first embodiment, and therefore their explanation will be omitted. In this modified example, the movement in the X-axis direction is performed by the belt conveyor, and the scanning in the Y-axis direction is performed on the optical system side, and the inspection object is placed on the belt conveyor in step S1', the belt conveyor is moved in S5', and the mirror angle is scanned in steps S5" and S9'. The measurement method at each coordinate (S7, S8) is the same as that described in the first embodiment, and therefore its explanation will be omitted.

[0052] By using a conveyor belt in this way, inspection can be performed automatically in-line, which has the effect of efficiently inspecting large amounts of discarded solar panels and quickly sorting them according to the presence or absence of defects and the quantity of defects. EXAMPLES

[0053] The third embodiment differs from the first embodiment mainly in that the anti-reflection film on the surface of the solar panel is simultaneously inspected.

[0054] First, we will explain the importance of inspection of the anti-reflective coating of solar panels in terms of reuse. An anti-reflective coating is a surface coating that prevents the reflection of light of a specific wavelength. In the case of solar panels, the wavelength range is adjusted to match the performance of the solar cell and the spectrum of sunlight to increase the efficiency of using solar energy.

[0055] When recycling glass on solar panels, it is important to evaluate the performance of the anti-reflective film, because it can be sold at a higher price depending on whether the anti-reflective film has deteriorated. For example, the anti-reflective film is expected to reduce reflections when observing the inside from the outside or taking a photograph, so it can be reused for applications that require higher aesthetics and transparency, such as aquariums and display cases, thereby increasing the profitability of glass recycling. However, the method of measuring scattered light generated from defective sites such as scratches as described in Example 1 has a problem that it is difficult to measure when the anti-reflective film is peeled off over a wide area and the smooth surface of the glass is exposed.

[0056] To address this issue, the configuration of an inspection device used in the third embodiment will be described with reference to Fig. 8. The inspection device additionally includes a reflection detection optical system 5 that detects reflected light L3. The wavelength of the light source 2a is set to the wavelength range of the anti-reflection film. When using such a light source, the reflectance is low in a portion where the anti-reflection film is not deteriorated, and the reflectance is high in a portion where the anti-reflection film is deteriorated. Therefore, it is possible to determine whether the anti-reflection film has deteriorated or not based on a change in the signal from the reflection detection optical system 5.

[0057] The wavelength range of the anti-reflection film can be measured by a separate measurement of the reflection spectrum, etc. It is not necessary to measure the wavelength range for all of the panels, and since solar panels discharged from a large-scale solar power plant, for example, are often standardized with the same model number, it is sufficient to perform a random inspection only once at the beginning and replace the light source 2a with a light source with an appropriate wavelength as necessary.

[0058] Another method for determining the wavelength range of an anti-reflective coating is to use a camera to determine the color of the glass. Glass with an anti-reflective coating appears colored in the complementary color of the wavelength range of the anti-reflective coating, so it can be determined by measuring the color of the glass surface using a camera or the like. When using a camera, the determination can be made using a camera mounted on a smartphone, for example, which has the effect of making it possible to carry out random inspections without the need for additional equipment.

[0059] Alternatively, it is possible to continue using a specific light source without replacing it depending on the measurement results. This is because solar panels use anti-reflection coatings in the visible region, such as green, which has the strongest intensity in the solar spectrum, so fixing to a green or white light source from the beginning can be used in most cases. In particular, using a white light source is desirable because it provides the effect of being able to use one light source for many types of solar panels, regardless of the type of anti-reflection coating.

[0060] Next, the configuration of the reflection detection optical system 5 will be described. The reflection detection optical system 5 is composed of at least a light receiving element 5b, and in this embodiment, it additionally has a lens 5a. The lens 5a focuses the reflected light L3 of the light L1 incident on the sample onto the light receiving element 5b. By focusing the light using a lens, it is possible to detect more reflected light, so that a clearer signal can be obtained, and an inspection that is robust against noise can be performed. However, although an example in which the lens 5a is used has been shown in embodiment 3, if the size of the light receiving surface of the light receiving element is sufficiently larger than the size of the reflected light L3, the lens 5a is not necessary.

[0061] Furthermore, the reflection detection optical system 5 may be additionally provided with one more lens and a pinhole, and may have a confocal configuration similar to that of the detection optical system 3. By configuring the reflection detection optical system 5 as a confocal configuration, it is possible to reduce the occurrence of erroneous detection of fluctuations in reflectance due to solar cells or wiring on the back surface of the glass.

[0062] Next, the inspection procedure in the third embodiment will be described with reference to Fig. 9. Steps S1 to S8 are similar to those in the first embodiment, and therefore the description will be omitted. In the third embodiment, step S6' is added to measure the signal amount of the reflection detection optical system. As already described, the reflectance of light increases in a location where the anti-reflection coating is deteriorated, so when the signal amount of the reflection detection optical system is equal to or greater than a threshold value, it is determined that the anti-reflection coating is deteriorated and the coordinates are recorded (S6', S7').

[0063] By simultaneously evaluating the reflectance fluctuation in this manner, it is possible to simultaneously inspect smooth defective areas that are difficult to discern using scattered light, in addition to defective areas such as scratches that can be discerned using scattered light.

[0064] The present disclosure is not limited to the above-described embodiments, but includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and are not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of a certain embodiment with the configuration of another embodiment or modified example, and it is also possible to add the configuration of another embodiment or modified example to the configuration of a certain embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0065] 1: Inspection object 2: Irradiation optical system 3: Detection optical system 4: Stage 5: Reflection detection optical system S: Inspection procedure L: Light ray

Claims

1. A surface inspection device for a solar panel protective glass having a solar cell and a protective glass for protecting the solar cell, an irradiation optical system having the light source and a polarizer that polarizes the light from the light source, and irradiating the light onto the protective glass; a detection optical system that detects light reflected by the protective glass, the detection optical system includes at least a lens, a polarizer, a pinhole, and a photodetector, and is arranged in this order on an optical path; A surface inspection device for a protective glass for a solar panel, characterized in that, during surface inspection, the lens is installed so that the position where the image of the protective glass surface is formed is on the plane of the pinhole.

2. The surface inspection device for a solar panel protective glass according to claim 1, When the numerical aperture of the detection optical system is NA, the wavelength is λ, and the thickness of the transparent member is t, 0.7λ / NA ２ a variable diaphragm for adjusting the angle so that t<t is provided between the lens and the polarizer of the detection optical system.

3. The surface inspection device for a solar panel protective glass according to claim 1, A surface inspection device for a protective glass for a solar panel, characterized in that the angle of incidence when light is irradiated from the irradiation optical system onto the protective glass is 50 degrees to 85 degrees.

4. The surface inspection device for a solar panel protective glass according to claim 1, A moving stage is provided for moving the solar panel protective glass to be inspected in two dimensions, A surface inspection device for a solar panel protective glass, comprising a memory means for storing the coordinates of the surface of the solar panel protective glass and the detection results detected by the detection optical system in association with each other.

5. The surface inspection device for a solar panel protective glass according to claim 1, the irradiation optical system irradiates a line-shaped light, A surface inspection device for a protective glass for a solar panel, comprising a moving stage that moves the solar panel protective glass to be inspected in a direction substantially perpendicular to the line-shaped light.

6. The surface inspection device for a protective glass for a solar panel according to claim 5, The surface inspection device for a protective glass for a solar panel is characterized in that the detection optical system is provided with a scanning mechanism that scans the detection range in a direction approximately parallel to the line-shaped light.

7. The surface inspection device for a solar panel protective glass according to claim 1, A surface inspection device for a solar panel protective glass, comprising a second detection optical system installed at an angle different from that of the detection optical system with respect to the surface of the solar panel protective glass that is the subject of surface inspection.

8. The surface inspection device for a solar panel protective glass according to claim 1, 13. A surface inspection device for a protective glass for a solar panel, comprising: a polarizer of the irradiation optical system having a polarization plane of s-polarized light; and a polarizer of the detection optical system having a polarization plane of p-polarized light.

9. The surface inspection device for a solar panel protective glass according to any one of claims 1 to 8, A surface inspection device for a solar panel protective glass, comprising an output means for outputting the coordinate position of a defect on the surface of the solar panel protective glass to be inspected, based on the measurement results from the detection optical system.

10. The surface inspection device for a solar panel protective glass according to claim 9, Furthermore, the output means is provided with a function for outputting at least one of information on the shape, size, and type of a defect present at the coordinate position, in the surface inspection device for a solar panel protective glass.

11. The surface inspection device for a solar panel protective glass according to claim 9, Furthermore, the surface inspection device for a protective glass for a solar panel is characterized in that the output means outputs the presence or absence of deterioration of the coating on the surface of the protective glass for a solar panel.

12. A method for inspecting a surface of a protective glass for a solar panel having a solar cell and a protective glass for protecting the solar cell, comprising the steps of: an irradiation optical system having a light source that irradiates light onto the protective glass and a polarizer that polarizes the light from the light source; and a detection optical system that detects light reflected from the protective glass when the light from the irradiation optical system is irradiated onto the protective glass, the detection optical system using an inspection device in which at least a lens, a polarizer, a pinhole, and a photodetector are arranged in this order; A surface inspection method for a protective glass for a solar panel, comprising the steps of: adjusting the lens during inspection so that the surface of the protective glass is positioned so as to form an image on the plane of the pinhole.

13. The method for inspecting a surface of a protective glass for a solar panel according to claim 12, the inspection device further includes a variable diaphragm between the lens and the polarizer of the detection optical system, When the numerical aperture of the detection optical system is NA, the wavelength is λ, and the thickness of the transparent member is t, During inspection, 0.7 λ / NA ２ The surface inspection method for a protective glass for a solar panel, comprising adjusting the variable diaphragm so that t<t.

14. The method for inspecting a surface of a protective glass for a solar panel according to claim 12, The inspection apparatus further includes a moving stage that moves the solar panel protective glass to be inspected in two dimensions, A surface inspection method for a solar panel protective glass, characterized in that the coordinates of the surface of the solar panel protective glass and the detection results detected by the detection optical system are linked and stored in a memory device as the results of inspection by the inspection device.

15. The method for inspecting a surface of a protective glass for a solar panel according to claim 12, The irradiation optical system of the inspection device irradiates a line-shaped light, Further, a moving stage is provided for moving the solar panel protective glass to be inspected in a direction substantially perpendicular to the line-shaped light, A surface inspection method for a protective glass for a solar panel, characterized in that the inspection is performed by moving the moving stage during the inspection.

16. The surface inspection method for a solar panel protective glass according to claim 15, the detection optical system of the inspection device includes a scanning mechanism that scans a detection range in a direction substantially parallel to the line-shaped light, A surface inspection method for a protective glass for a solar panel, comprising the steps of: scanning the surface of the protective glass for a solar panel with the scanning mechanism during inspection.

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