| 摘要 |
PURPOSE:To improve the responding speed of an endoscope without changing the light distribution characteristic and spectral characteristic of lighting lights, by providing a liquid crystal board divided by numerous electrodes on a concave mirror which changes the lights of a light source to parallel lights. CONSTITUTION:Lights of the light source 12 of a lighting device 11 are changed to parallel lights by means of a concave mirror 13 and an object is irradiated by the parallel lights passed through a light guide 10. A liquid crystal board 16 equipped with transparent electrodes 16a and 16c which are closely concentrically arranged is glued to the surface of the concave mirror 13. A light adjusting signal from an image pickup element 4 is inputted in the liquid crystal board 16 through the objective lens 3 of an endoscope inserting section and a voltage corresponding to the signal is selectively applied across the electrode 16a. Thus a nonreflecting section 16b is formed. Therefore, the optimum lighting intensity to the object is automatically adjusted and the whole mirror 13 is uniformly changed. Accordingly, the lighting light quantity can be adjusted with excellent responsiveness without changing the light distribution characteristic and spectral characteristic.
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