| 摘要 |
PURPOSE:To make a multilevel adjustment of the quantity of light by sealing plural liquid-crystal surfaces, which are patterned in nearly doughnut shapes of different size having the same center provide light transmission by applying a voltage selectively, in sealing glass. CONSTITUTION:A light quantity stop device 1 is formed by laminating discoid sealing glass layers 2 and 3, and liquid-crystal surfaces 4 (4a-4e) in specific shapes are sealed in the glass layers 2 and 3. For example, the minimum and circular liquid-crystal surface 4a and liquid-crystal surfaces 4b and 4c which are patterned in doughnut shapes to different size are sealed in the glass layer 2, and liquid-crystal surfaces 4d and 4e which are patterned in doughnut shapes to different size are sealed in the glass layer 3. Then the liquid-crystal surfaces 4a, 4b, and 4c, and 4d and 4e are sized overlapping one another in a light transmission direction and applied selectively with a voltage independently. Thus, shield and circular openings A1-A5 adjust the quantity of light in six stages with light transmission patterns.
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