| 摘要 |
PURPOSE:To obtain the inexpensive polygon mirror having high accuracy by molding using a resin material by setting the average grain sizes of the glass powder to be mixed to specular surface parts on the outer periphery smaller than the average grain sizes of the glass powder to be mixed in the central part. CONSTITUTION:The molded polygon mirror 10 is produced by forming both of the specular surface constituting parts on the outer periphery having, for example, a hexagonal shape, and the central part 12 of a flat hexagonal shape of a mixture composed of the glass powder and polymerizable compsn. and polymerizing these parts. While the fine grain glass powder of 0.1 to 5mum average grain sizes is used for the glass powder to be mixed in the specular surface constituting part 11, the coarse grain glass powder of 1.0 to several 10mum average grain sizes is used for the glass powder to be mixed in the central part 12. The mixing ratios of the fine grain glass powder and the coarse grain glass powder with the polymerizable compsn. for both of the specular surface constituting parts 11 and the central part 12 are specified to 9:1 to 3:1 by weight. The generation of shrinkage at the time of polymn. molding is substantially prevented and the precise shapes are easily obtd. if the mixing ratio of the glass powders is increased in such a manner. |
