Diode lasers help put tight seal on flat panel displays

17 Jun 2002

Florod Corporation, a U.S. producer of flat panel display (FPD) manufacturing equipment, has developed a glass vacuum sealing system that employs high-power diode lasers to bond the faceplate to the bottom plate of plasma-addressed and field-emission FPDs. Working in tandem with a vacuum oven, two 15-watt integrated diode laser modules supplied by Opto Power Corporation assist Florod's sealer in applying computer-controlled, direct thermal energy to a frit-sealing material, a mixture of glasses that melts at a lower temperature than the glass in FPDs, to bond the plates together. The modules deliver the near-infrared CW laser energy via fiberoptic cable.

Traditionally, FPD manufacturers have employed epoxy-based or high-temperature glass frit sealing machines, depending on the kind of display, to bond the top plate to the bottom plate. The new sealing process begins by placing two pre-aligned glass plates (up to 14" diagonal) - with the glass frit material sandwiched in between - in an oven programmed to raise the temperature at a preselected rate, typically a few Celsius degrees per minute. When the oven reaches its target temperature (usually around 300 Celsius), the diode laser modules are computer activated, bringing the frit in the seal area up to its melting temperature. Once the frit melts, it bonds the two plates together, creating a vacuum seal. Because this approach makes the seal without heating the entire surface area of the panels, it prevents unnecessary heat stress on the plates.