| 摘要 |
PURPOSE:To always obtain satisfactory glare-proof effects, by detecting light leaking from a part on the surface of a front windshield pane which may not be covered with a movable sunvisor, with the use of a photosensor to reduce the light transmission of a variable light transmission panel. CONSTITUTION:A variable light transmission type panel 11 having a transparency which is reduced by the action of liquid crystal disposed therein and electrically operated, is laid on the surface of a front windshield in the upper edge part of the center section of the front windshield pane which may not be covered with a movable sunvisor. Further, a photo-sensor composed of a photo-transistor Q1 is attached to the upper edge part of one side section of the front windshield pane. When light is incident upon the photo-sensor Q1, if a voltage at a non-reversible input terminal of a comparator CMP exceeds a predetermined value while switches S1, S2 associated with a head light turn-on switch and a wiper operating switch are both turned off, the transistor Q1 is turned on, resulting in energization of the variable light-transmission panel 11 by means of a liquid crystal drive circuit, to reduce the light transmission of the panel.
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