| 摘要 |
PURPOSE:To produce easily and economically a diffusion degree variable focusing plate provided with a range finding part at its center by sealing a substance of which scattering characteristic is changed by applying a voltage between two transparent sealing members provided with transparent electrodes at respective insides. CONSTITUTION:Nematic liquid crystal having a strong dynamic scattering mode changing its diffusion characteristic when the voltage is applied is used for liquid crystal 15. A recessed part 19 is formed on a transparent sealing member 14 e.g. on one side at least out of two transparent sealing members 11, 12 and a range finding member 18 such as a split image is unitedly formed on the bottom of the recessed part 19. A peripheral edge sealing member 20 seals the peripheral edge part between the transparent sealing members 11 and 12. Since the voltage is applied to the liquid crystal 15 during a switch 17 is closed, the diffusion degree is large, and similar characteristics as an ordinary focusing plate having a mat is obtained, but when the switch 17 is turned off, the diffusion degree is reduced and the focusing plate can be used as a transparent focusing plate. |
