| 摘要 |
PURPOSE: To make the luminance of liquid crystal at the time of low luminance display extremely low compared with the luminance at the time of high luminance display. CONSTITUTION: An extinction filter 21 is arranged at one half part in a thickness direction on one side surface of a light transmission plate 13, and a 1st fluorescent lamp 22 is provided opposite the filter 21 and surrounded by a light shielding cover 23. Meanwhile, a 2nd fluorescent lamp 24 is provided to be opposed to the other half part on one side surface of the plate 13, and surrounded by a reflection mirror 15. A low luminance state and a high luminance state are switched by switching the lighting of both fluorescent lamps and the luminance in the low luminance state is made proportional to the transmissivity of the filter 21. Therefore, by setting the transmissivity to 0.1%, for example, the low luminance is made about 1/1000 of the high luminance. |
