JPH04339247A - Automatic inspecting device for flaw of solar battery - Google Patents

Abstract

PURPOSE:To inspect the flaw of a solar battery within a short time on the basis of a definite inspection standard. CONSTITUTION:The light emitted from a light source 2 is condensed in an emitting part 3 to irradiate the surface of a solar battery 1 and a light detecting part 4 detects the scattering reflected light from the surface of the solar battery to output the image signal proportional to the quantity of light. A quaternarizing circuit 5 allows the position signals S from a surface scanning means 10 scanning the surface of the solar battery 1 to correspond to an image signal to convert the signal to a quaternarized multivalved image signal. The image formed by the multivalent image signal is set to the image of a predetermined region in a region determining part 6 and this image is converted to an image component showing flaws and dust in an unnecessary part erasing part 7 and further set only to an image showing flaws in a single point erasing part 8 and it is judged whether the surface of the solar battery has flaws larger than ones of a area preset by an area judging part 9 and the judgment result is outputted from the area judging part 9.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic solar cell flaw detection apparatus, and more particularly to an automatic solar cell flaw detection apparatus for automatically detecting the presence or absence of flaws on the surface of a solar cell.

0002

2. Description of the Related Art FIG. 8 is a plan view showing an example of a solar cell.

The solar cell 1 has a battery surface 16, an edge 13 having a brightness different from that of the battery surface 16, an electrode wire 11 that collects the power generated on the battery surface, and an electrode wire 11 that transmits the power collected by the electrode wire 11 to the outside. It consists of an electrode 12 taken out.

[0004] Conventionally, all flaws in solar cells have been detected by visual inspection by an operator. The interval between adjacent electrode lines 11 is about 2 mm, and the width of the electrode lines 11 is 0.2 mm.
The width of the scratch 14 that normally occurs on the battery surface 16 is about 0.01 mm, which is narrower than the width of the electrode wire 11.

[0005] The operator visually observes the state of reflection from the battery surface 16 while illuminating the surface of the solar cell 1, which is the object to be inspected, with a light source such as a fluorescent lamp, and detects any flaws on the battery surface 16. I was going.

[0006]

[Problems to be Solved by the Invention] The conventional method for detecting flaws on the cell surface of a solar cell as described above is based on visual inspection by an operator, which has the disadvantage that the inspection results vary because the inspection standards differ depending on the operator. there were. In addition, solar cells have many electrode wires, and the width of the wires is about 10 times that of the flaw to be detected, so when detecting a flaw, it can be confused with a flaw.
There are disadvantages in that flaws are often overlooked, and inspection requires a lot of time, and as the inspection time progresses, flaws may be overlooked due to worker fatigue.

An object of the present invention is to automate the detection of scratches on the cell surface of a solar cell as described above, so that the device detects the scratches instead of the operator, the inspection results are constant regardless of the operator, and the inspection result is more stable than before. It is an object of the present invention to provide an automatic solar cell flaw inspection device that can perform inspection within a short time.

[0008]

[Means for Solving the Problems] The automatic solar cell flaw detection device of the present invention includes: a laser light source; a light emitting section that focuses the laser light emitted from the laser light source onto a convergence point close to one point; Electricity that collects at least a portion of the scattered light of the laser beam reflected from the surface of the solar cell, which is the object to be inspected, located at the condensing point, and has a level proportional to the amount of the collected scattered light. The light is focused over a predetermined range while maintaining a constant relative positional relationship between the light receiving section that converts it into a signal and outputting it, the light emitting section, and the light receiving section and positioning the light focusing point on the surface. surface scanning means for scanning a point, detecting the position of the focal point on the surface, and outputting a position signal indicating the position; and dividing the output from the light receiving section into predetermined level ranges; a multi-value image signal in which the multi-value signal is associated with a position on the surface where the signal is measured based on the position signal; , an area determination unit that extracts a predetermined area of the object to be inspected from an image generated by the multilevel image signal and outputs it as an inspection area signal; an image portion that displays the scratches and dust by converting a level value of an image signal component corresponding to an image region other than the image portion that displays the dust portion into a level value that minimizes the light amount among the multi-value levels; an unnecessary part erasing unit that outputs an unnecessary part erasing signal that erases image areas other than the above; a single-point erasing unit that outputs a dust erasing signal in which the image corresponding to the dust is erased by converting the light amount to a level value that minimizes the amount of light among the digitalization levels; The area of the image of each area other than the area corresponding to the level where the light amount is the minimum among the value conversion levels is calculated for each area, and the area of each area for each area is compared with the internally stored judgment value. If there is an area with an area exceeding the judgment value, it is determined that there is a flaw, and a signal indicating that the inspection result is rejected is output, and each area is less than or equal to the judgment value. and an area determination unit that outputs a signal indicating that the inspection result is acceptable.

[0009]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an automatic solar cell flaw detection apparatus according to the present invention. As the light source 2, for example, a laser light source is used. The light emitted from the light source 2 is condensed by the emission part 3 and condensed near a point P, for example, in a substantially dot shape with a diameter of about 0.1 mm. The cell surface of the solar cell 1, which is the object to be inspected, is positioned near a point P by the surface scanning means 10. The surface scanning means 10 is a solar cell 1
While positioning one of the battery surfaces at point P, the device moves in a predetermined direction along the X-Y plane parallel to the battery surface and scans the entire surface within a preset area. Further, at the same time as scanning, the current position from a certain reference point to point P is output as a position signal S.

The light receiving section 4 is located at a fixed position relative to the emitting section 3 and the light source 2, and specularly reflected light, that is, Snell's law, out of the light reflected from the battery surface portion located at a point P on the battery surface. It receives the scattered reflected light excluding the reflected light according to the above, and outputs an image signal converted into a signal with a level proportional to the amount of received light. The quaternary circuit converts the level of the above-mentioned input image signal into a signal having a level value of one of four predetermined levels, and when the light receiving unit 4 detects this signal, the battery A multivalued image signal associated with a position signal S indicating a position on the surface is output. In the above-described level conversion of the input signal, the entire level range of the input image signal is divided into four predetermined areas, and it is determined in which of the above areas the level of the input image signal is included. The system detects whether the level of the input image signal is present and converts it into a signal having a predetermined level representative of the area containing the level of the input image signal.

FIG. 2A is an explanatory diagram showing an example of the relationship between the amount of scattered reflected light from each part on the solar cell and the reflected part. For example, the amount of scattered reflected light from a normal battery surface is 0.2 μW, and the amount of scattered reflected light from a scratched portion is 0.4 μW to 2 μW.

FIG. 2(B) is an explanatory diagram showing an example of the above-mentioned multivalue conversion. In FIG. 2(B), an example of the case of 4-value conversion is shown. That is, when the light receiving section 4 receives scattered reflected light with a scattered reflected light amount P of less than 0.2 μW, and an image signal with a level proportional to this light amount is output from the light receiving section, the image signal is converted by the quaternization circuit 5. The level of the output multivalued image signal is converted into a signal representing level 1. If the amount of scattered reflected light P is 2 μW or more and the amount of scattered reflected light is less than 20 μW, and the light receiving section 4 receives the scattered reflected light and outputs an image signal proportional to this amount of incident light to the 4-value conversion circuit 5, the 4-value conversion circuit converts this signal into a signal representing level 3.

FIG. 3 is an explanatory diagram showing an example of an image generated by a multivalued image signal outputted from the quaternary circuit 5. As shown in FIG. In the following examples, the amount of scattered reflected light and the level of the multivalued image signal follow the relationship shown in FIG.
It is assumed that the relationship (A) is followed. That is, an image corresponding to a normal battery surface is converted to a level 1 normal battery surface image 26 generated by the signal representing level 1 described above, and an image corresponding to a scratch on the battery surface is converted to a level 2 normal battery surface image 26.
The image corresponding to the electrode line is generated by two level 2 electrode line images 21a generated by the signal representing level 2 and the signal representing level 3. It is converted into a level 3 electrode line image 21b. Furthermore, the image corresponding to the edge of the solar cell is converted into a level 4 edge image 23 generated by the signal representing level 4, and the image corresponding to the electrode portion is converted to a level 4 electrode portion image 23 generated by the signal representing level 4. 22, and the image corresponding to dust attached to the battery surface is converted into a level 2 dust image 25 generated by a signal representing level 2. FIG. 4 is a partially enlarged view of FIG. 3.

As is clear from FIG. 3, the image portion represented at level 4 is only the portion corresponding to the edge 13 and the electrode portion 12 shown in FIG. The area determining unit 6 erases the image signal of the portion corresponding to the image of the area outside the level 4 edge image 23 and the level 4 electrode part image 22 from among the generated multivalued image signals. The region determining section 6 outputs this processed signal to the electrode line erasing section 7 as an inspection region signal. FIG. 5 is an explanatory diagram showing an example of an image generated by the inspection area signal output from the area determination unit 6.

Among the images generated by the inspection area signals, the image corresponding to the electrode line 11 shown in FIG. 8 is the level 2 electrode line image 2 generated by the signal represented by level 2.
The level 3 electrode line image 21b generated by the two locations 1a and the signal represented by level 3 is the image portion of the area sandwiched between the level 2 electrode line images 21a. On the other hand, in the image generated by the inspection area signal, the flaw 14 in FIG.
The image corresponding to is the level 2 flaw image 24 generated by the signal represented by level 2, and is the image portion formed only by the level 2 signal.Similarly, the image formed by dust is also represented by level 2. This is an image based only on the signals that are transmitted. Therefore, the image portion corresponding to the electrode line 11 is the only portion in which the image portions represented by the signal represented by level 2 are parallel and the image portion represented by the signal represented by level 3 is present in between. In addition, since the image portion corresponding to the edge 13 and the electrode portion 12 in the image generated by the inspection area signal is an image formed by the signal represented by level 4, the level 2 dust image 25
Since the level 2 flaw image 24 is formed by a signal of a different level, the inspection area signal is input to the unnecessary image erasing unit 7, and only the image portion represented by level 2 is selected from the image generated by the inspection area signal. All signal components that generate other image regions are converted to level 1 signals, i.e., the signals corresponding to images representing scratches and the signal components corresponding to images representing dust are left as is, and the other signal components are converted to level 1 signals. are converted to level 1 signals, leaving only the image parts corresponding to scratches and dust and erasing the other image parts. The unnecessary image erasing section 7 outputs the signal subjected to such conversion as an unnecessary part erasing signal. FIG. 6 is an explanatory diagram showing an example of an image generated by the unnecessary portion erasure signal. In FIG. 6, only a level 2 flaw image 24 corresponding to a flaw and a level 2 dust image 25 corresponding to dust exist as images.

The size of the dust is usually included in a circular area with a diameter of 0.1 mm, but the size of a scratch that interferes with the operation of the solar cell and should be judged as defective is 0.1 mm in width.
The length is approximately 2 mm or more.

The single point erasing unit 8 inputs the above-mentioned unnecessary part erasing signal, and sets the level of the signal corresponding to the image portion corresponding to the object having a diameter of 0.1 mm or less on the battery unit 6 to level 1.
That is, a dust erasure signal in which the image portion corresponding to the dust is erased is output to the area determining section 9. FIG. 7 is an explanatory diagram showing an example of an image generated by the dust erase signal.

The area determination unit 9 stores a predetermined determination value, and the area determination unit 9 stores a predetermined determination value, and determines the level 2 on the image generated by the dust erasure signal.
The area of the flaw image 24 is calculated and set as an area value, and if the area value is equal to or smaller than the above-mentioned judgment value, it is judged that there is no problematic flaw and the inspection result is passed. Output a signal, for example, a logical value “1”, and if
If the above-mentioned area value is equal to or greater than the determination value, a determination signal indicating that the inspection result is rejected, for example, "0" is output.

[0020] The above-mentioned judgment value is, for example,
The value may be set to a value corresponding to the area of the image generated by the dust erasing signal, which corresponds to 0.2 square mm, which is the area of a rectangular portion having a top width of 0.1 mm and a length of 2 mm.

In the above embodiments, the input image signal is converted into a 4-valued image signal by the 4-valued image signal conversion circuit 5; It is clear that a multi-value conversion circuit that converts into a multi-value signal having the following values may be used in place of the quaternary conversion circuit 5.

[0022]

[Effects of the Invention] As explained above, the automatic solar cell flaw detection device of the present invention automates the detection of flaws on the cell surface of solar cells, the device detects flaws in place of the operator, and the inspection results are It has the effect of being able to perform inspections in a shorter time than before, without depending on the operator.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic solar cell flaw detection device of the present invention.

[Fig. 2] Fig. 2(A) is an explanatory diagram showing an example of the relationship between the amount of scattered reflected light from each part on the solar cell and the reflected part, and Fig. 2(B) is an explanatory diagram showing an example of multi-leveling. FIG.

FIG. 3 is an explanatory diagram showing an example of an image generated by a multivalued image signal output from the quaternary circuit 5 of FIG. 1;

FIG. 4 is a partially enlarged view of FIG. 3;

FIG. 5 is an explanatory diagram showing an example of an image generated by an inspection area signal output from the area determination unit 6 of FIG. 1;

6 is an explanatory diagram showing an example of an image generated by an unnecessary portion erasing signal outputted by the unnecessary portion erasing unit 7 of FIG. 1. FIG.

7 is an explanatory diagram showing an example of an image generated by a dust erasing signal outputted by the single point erasing section 7 of FIG. 1. FIG.

FIG. 8 is a plan view showing an example of a solar cell.

[Explanation of symbols]

1. Solar cells 2 Light source 3 Emission part 4 Light receiving section 5 Quaternary conversion circuit 6 Area determination section 7　　　　Unnecessary part deletion section 8 Single point erasure section 9 Area determination section 10 Surface scanning means

Claims (1)

[Claims] 1. A laser light source, a light emitting unit that focuses the laser light emitted from the laser light source onto a convergence point close to one point, and a surface of a solar cell that is an object to be inspected located at the convergence point. a light receiving unit that collects at least a portion of the scattered light of the laser light reflected from the laser beam, converts it into an electrical signal having a level proportional to the amount of the collected scattered light, and outputs the electrical signal;
The light focusing point is scanned over a predetermined range while keeping the relative positional relationship between the light emitting section and the light receiving section constant and the light focusing point is positioned on the surface, and the light focusing point on the surface is scanned. A surface scanning means detects the position of the light spot and outputs a position signal indicating the position, and the output from the light receiving section is divided into predetermined level ranges and converted into a multivalued signal indicating each of these levels. a multi-value conversion circuit that outputs a multi-value image signal in which a multi-value signal is associated with a position on the surface where the signal is measured based on the position signal; and an image generated by the multi-value image signal. an area determination unit that extracts a predetermined area of the object to be inspected and outputs it as an inspection area signal; and an image area other than the image part that displays scratches and dust on the surface from within the image generated by the inspection area signal. an unnecessary portion erasing signal that erases an image area other than the image area where the scratches and dust are displayed by converting the level value of the image signal component corresponding to the image signal component into a level value at which the light amount is the minimum among the multi-value levels; and a signal level value of an image area corresponding to the dust attached to the surface in the image generated by the unnecessary part erasing signal to a level value of the signal in the image area corresponding to the dust attached to the surface when the light intensity is the minimum among the multi-value levels. a single point erasing unit that outputs a dust erasing signal that is converted to a certain level value and erases an image corresponding to the dust;
The area of the image of each area other than the area corresponding to the minimum level of the light intensity among the multi-value levels in the image generated by the dust erasing signal is calculated for each area, and the judgment value and the area are stored internally. Compare each of the other areas, and if there is an area with an area exceeding the judgment value, it is determined that there is a flaw, and a signal indicating that the inspection result is rejected is output. An automatic solar cell flaw detection device comprising: an area determination section that outputs a signal indicating that the inspection result is acceptable when each area is less than or equal to the determination value.