OPTICAL IMAGING APPARATUS AND METHOD FOR INSPECTING SOLAR CELLS

• US 20090238444A1
• Filed: 07/08/2008
• Published: 09/24/2009
• Est. Priority Date: 03/19/2008
• Status: Abandoned Application

• Current Assignee: Viswell Technology Co., Ltd.
• Original Assignee: Viswell Technology Co., Ltd.
• Inventors: CHEN, KUANG YU, SU, CHIA HO, LIN, WEN SHENG
• Application Number:
  US12/169,251
• Publication Number:
  US 20090238444A1
• Time in Patent Office: Days
• US Class Current: 382/149
• CPC Class Codes: G01M 11/00 Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
• CPC Class Codes: G01M 99/002 Thermal testing flaw detection G01N25/72
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence
• CPC Class Codes: H01L 21/67271 Sorting devices
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

An optical imaging apparatus for inspecting a solar cell includes a power supply configured to apply a reverse biased voltage to the solar cell such that shunt defects in the solar cell will generate heat, a thermal imaging device configured to obtain the thermal image of the solar cell, a computing unit including a thermal image analysis module configured to identify hot spots in the thermal image, a locating module configured to locate the center positions of the hot spots, a visible image analysis module configured to identify the defect features of the hot spots, and a visible light imaging device configured to acquire visible images of the hot spots.

Claims

1. An optical imaging apparatus for inspecting a solar cell, comprising:

a power supply configured to apply a reverse biased voltage to the solar cell;

a thermal imaging device configured to obtain a thermal image of the solar cell; and

a computing unit including a thermal image analysis module configured to identify a hot spot in the thermal image and a locating module configured to locate the hot spot.

2. The apparatus of claim 1, wherein the temperature of the hot spot is higher than a temperature threshold and the size of the hot spot is greater than an area threshold.

3. The apparatus of claim 1, further comprising a drive module configured to move the thermal imaging device.

4. The apparatus of claim 1, wherein the reverse biased voltage is the breakdown voltage of the p-n junctions of the solar cell.

5. The apparatus of claim 1, further comprising a visible light imaging device configured to obtain a visible image of the hot spot.

6. The apparatus of claim 5, wherein the computing unit further comprises a visible image analysis module configured to identify the defect feature of the hot spot.

7. The apparatus of claim 5, further comprising a drive module configured to move the thermal imaging device and the visible light imaging device.

8. The apparatus of claim 5, further comprising a display for showing the image obtained by the thermal imaging device or the visible light imaging device.

9. The apparatus of claim 5, wherein the visible light imaging device comprises a camera.

10. The apparatus of claim 9, wherein the camera is linescan camera, area camera, CCD or CMOS camera.

11. The apparatus of claim 9, further comprising a laser pointer for pointing the location of the solar cell corresponding to the center of the visible image.

12. The apparatus of claim 1, further comprising a moving stage configured to move the solar cell.

13. The apparatus of claim 12, wherein the moving stage is an XY moving stage.

14. The apparatus of claim 12, wherein the moving stage is driven by automatic driving forces or manual driving forces.

15. A method for inspecting a solar cell, comprising the steps of:

applying a reverse biased voltage to the solar cell;

obtaining a thermal image of the solar cell by a thermal imaging device; and

identifying a hot spot having a temperature higher than a temperature threshold and a size larger than an area threshold.

16. The method of claim 15, further comprising the steps of:

calculating a center position of the hot spot;

obtaining a visible image of the hot spot by a visible light imaging device according to the center position;

identifying a defect feature of the hot spot; and

storing an analysis result of the defect feature in a statistical database.

17. The method of claim 16, wherein the reverse biased voltage is the breakdown voltage of p-n junctions.