Apparatus for detecting particles in flat glass and detecting method using same

1. An apparatus for detecting particles in a flat glass in the state of transferring to decide whether the particles contained in the flat glass are benign defects including bubbles or malignant defects including metals, comprising:

a first photographing device, comprising:

a first illumination unit which is installed in one region selected from upper and lower regions on the basis of flat glass and which illuminates a light obliquely based on the normal vector of the flat glass;

a first polarizer which is installed between the illumination unit and the flat glass, and has a first polarization direction;

a first camera which is installed on the normal vector of the flat glass in the opposite direction where the first illumination unit is installed on the basis of the flat glass and which receives the light diffused by defects; and

a second polarizer which is equipped in a space between the first camera and the flat glass; and

a second photographing device, comprising:

a second illumination unit which is installed in same region selected from upper and lower regions on the basis of flat glass and which illuminates a light obliquely based on the normal vector of the flat glass;

a third polarizer which is installed between the second illumination unit and the flat glass, and has a second polarization direction;

a second camera which is installed on the normal vector of the flat glass in the opposite direction where the second illumination unit is installed on the basis of the flat glass and which receives the light diffused by defects; and

a fourth polarizer which is equipped in a space between the second camera and the flat glass;

wherein the first polarizer and the second polarizer have different polarization directions in the range of 0° to 20°, and the third polarizer and the fourth polarizer have different polarization directions in the range of 70° to 90°,

wherein the light illuminated from the first illumination unit and the second illumination unit does not enter directly to the first camera and the second camera respectively, and the light being obliquely illuminated from the first illumination unit and the second illumination unit directly to the first polarizer and the third polarizer, respectively, and directly from the first polarizer and the third polarizer to the flat glass.

2. The apparatus of claim 1 , wherein

the second polarizer and the fourth polarizer are attached to the front lenses of the first camera and the second camera in film type.

3. The apparatus of claim 1 , wherein

a transferring device for transferring the flat glass is further comprised.

4. The apparatus of claim 1 , wherein

the first camera and the second camera are configured as a plurality of line CCD cameras, respectively.

5. The apparatus of claim 1 , wherein

the second polarizer has the same polarization direction as that of the first polarizer.

6. The apparatus of claim 1 , wherein

the fourth polarizer has a polarization direction vertical to that of the first polarizer.

7. The apparatus of claim 1 , wherein

the flat glass is for protecting a solar cell.

8. A flat glass particle detecting method for distinguishing whether defects contained in flat glass are benign particles including bubbles or malignant particles including metals, comprising the steps of:

a first step of obtaining an image by irradiating polarized light obliquely based on the normal vector of the flat glass on the flat glass, and by photographing light transmitted directly from an illumination unit and to and through a polarizer which has a polarization direction in the range of 0° to 20° that is different from a polarization direction of the polarized light;

a second step of obtaining an image by irradiating polarized light obliquely based on the normal vector of the flat glass on the flat glass, and by photographing light transmitted directly from an illumination unit and to and through a polarizer which has a polarization direction in the range of 70° to 90° that is different from the polarization direction of the polarized light; and

a third step of distinguishing whether defects contained in the flat glass are malignant particles that affect the glass quality or benign particles that do not affect the glass quality, by comparing the image obtained from the first step with the image obtained from the second step, wherein

the first step and the second step are carried out at the same time or performed regardless of order.

9. The method of claim 8 , wherein

the polarization direction of the polarized light is matched with the polarization direction of the polarizer in the first step.

10. The method of claim 8 , wherein

the polarization direction of the polarized light is vertical to the polarization direction of the polarizer in the second step.

11. The method of claim 8 , wherein

the flat glass is for protecting a solar cell.