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FPD: Backlight Mold

Case 4: FPD Light Guide Plate Mold

Digitizing of a variety of media, including hi-vision broadcasting and media distribution, has been standardized. The flat panel display (FPD) industry, in particular, has shown dramatic growth.

As large FPDs have become popular, the molds for FPD light guide plates and the lapping machines for the lip dies used to coat photoresist films have necessarily become larger. To meet this trend, we have achieved a mirror surface finish of 42” light guide plates using the world-largest diamond lapping system EJW-3200IF, which is equipped with a lapping plate of more than 3 meters in diameter.

Equipment and Processes

Conditions Lapping Polishing
Machine model EJW-3200IF GNC EJW-3200I
Consumables 3 µm-OV95PC HCL XL
Running time 120 minutes 10 minutes
Roughness Ra <0.2 µm  Ra <5 nm


Process Result

We could achieve a uniform surface roughness over the entire surface of the mold for a large-FPD light guide plate.
Surface roughness Ra = 2 µm or less
Flatness at 17” in diameter: 2 µm or less