Method and apparatus for inspection of multi-junction solar cells
AssigneeNorthrop Grumman Corporation
InventorsMau-Song Chou, Jonathan W. Arenberg, Mark A. Menard
Life of this patent
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Abstract
A technique for providing high-contrast images of defects in solar cells and solar panels, by illuminating each cell under inspection with broadband infrared radiation, and then forming an image of radiation that is secularly reflected from the cell. Multi-junction solar cells have a metal backing layer that secularly reflects the illumination back into an appropriately positioned and aligned camera, selected to be sensitive to infrared wavelengths at which the solar cell materials are relatively transparent.
Claims18
A method for detecting defects in at least one multi-junction solar cell, comprising:
- illuminating at least one multi-junction solar cell with infrared radiation from a flat-panel illuminator oriented to direct the radiation onto the solar cell at a selected incident angle;
- positioning an infrared camera to receive specularly reflected radiation from the at least one multi-junction solar cell;
- and
- forming an image in the camera, representative of radiation specularly reflected from the at least one multi-junction solar cell, wherein any defects in the at least one solar cell are visible in the image as contrasting features, and wherein the flat-panel illuminator radiates light over a broad band of infrared wavelengths and the camera is sensitive in a wavelength of approximately 3-5 μm.
Apparatus for detecting defects in at least one multi-junction solar cell, comprising:
- a flat-panel illuminator, for illuminating at least one multi-junction solar cell with infrared radiation, wherein the flat-panel illuminator is oriented to direct the radiation onto the solar cell at a selected incident angle;
- an infrared camera positioned to receive specularly reflected radiation from the at least one multi-junction solar cell;
- and
- means for forming an image in the camera, representative of radiation specularly reflected from the at least one multi-junction solar cell, wherein any defects in the at least one solar cell are visible in the image as contrasting features, and wherein the flat-panel illuminator radiates light over a broad band of infrared wavelengths and the infrared camera is sensitive in wavelength range of approximately 3-5 μm.
Dependencies are inferred from the claim text.