| 摘要 |
PROBLEM TO BE SOLVED: To easily produce a glass sheet having high forgery preventing ability by applying a laser sensitive coating consisting of a base polymer and a radiation sensitive additive to a glass sheet, curing the coating and carrying out writing with laser. SOLUTION: An unsatd. polyester, epoxy polyester and urethane acrylate are preferably used as the base polymer. A color pigment or a metallic salt such as a copper salt or a titanium compd., preferably copper hydroxyphosphate or Iriodin is used as the radiation sensitive additive and the amt. of the additive used is 0.001-3 wt.%. The laser sensitive coating may be applied between two glass sheets and cured. In this case, the coating acts as an adhesive medium. Writing is carried out using a high energy source such as neodymium-yttrium- aluminum-garnet laser which emits beam of 1.06μm wavelength.
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