| 摘要 |
PURPOSE: To obtain a filter having excellent light diffusion property and heat resistance by constituting the filter of a sheet made of a single non-stretched polytetrafluoroethylene fiber or a mixture with an inorg. fiber. CONSTITUTION: This filter consists of a sheet made of a single non-stretched polytetrafluoroethylene fiber(PTFE fiber) or a mixture of PTFE fiber and inorg. fiber. Or, the sheet is produced by using a single PTFE fiber with a viscoat as a matrix or mixing in with an inorg. fiber, making a sheet in a wet process and sintering. For sintering, cobalt oxide is added before the sheet making process or sintering process. The purpose of the filter can be enough obtd. with a single PTFE fiber, however, to further improve the heat resistance and to prevent deterioration by heat generated from an illuminator for a long time, inorg. fibers such as glass fiber and ceramic fiber can be added. |
