| 摘要 |
<p>PURPOSE:To allow the color control over the entire visible light region by separately providing a short-pass filter group which is continuously or stepwise changed in transmission wavelength region and a long-pass filter group which is continuously or stepwise changed in transmission wavelength region. CONSTITUTION:The short-pass filter group 1 and long-pass filter group 2 having the transmission wavelengths varying continuously or stepwise are not formed on the same base material but are separately formed (for example, on separate base materials). If both of two sheets of such filter groups are formed as a movable type, the way of superposing the short-pass filter group 1 and the long-pass filter group 2 can be changed by adjusting the positional relation of both and the combinations of the characteristics of the short-pass filters and the long-pass filters can be freely selected. The independent control of the transmission bands and the widths thereof is possible in this way and the color control over the entire visible light region is possible.</p> |
