Sensors Unlimited, Inc., a part of Goodrich Corporation, has announced their high-resolution, shortwave infrared (SWIR) area and linescan cameras are being used to improve the manufacturing yield of PV cells. SWIR technology is well-suited to monitor the quality of solar thin-films, concentrated PV, and crystalline cells to maximize efficiency of the solar cell manufacturing process through final assembly of the completed modules. The InGaAs-based SWIR cameras, which operate between 0.9 to 1.7 microns, are ideal for inspecting silicon boules and wafers due to the material’s transparency beyond 1.2 microns. In machine vision applications, Goodrich shortwave infrared sensors can reveal voids in silicon boules, bricks, and ingots before they are sliced into wafers to produce mono- and multi-crystalline solar cells. They can also detect hidden cracks by mapping stress in silicon wafers and films made for solar collectors. SWIR cameras can further spot defects in the material and/or saw marks inside or on the opposite side of a silicon wafer. By applying forward bias to cells, the SWIR cameras are used to gauge cell efficiency and uniformity. This not only aids improvement of cell manufacturing processes, but also helps in matching cells with similar efficiencies to assemble into modules. The latter step prevents the loss of energy from the stronger cells, which would be lost in heating the inefficient cells.

Sensors Unlimited, Inc.
www.sensorsinc.com