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US 4,807,091 AGranted
Illuminating device for an electric part
AssigneeAlps Electric Co., Ltd.
InventorKosei Obata
Life of this patent
Estimating the term…
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AssigneeAlps Electric Co., Ltd.
InventorKosei Obata
Estimating the term…
An illuminating device for an electric part which can illuminate a light conducting member uniformly with a simple construction. The illuminating device comprises an annular filter having a light passing zone and a light absorbing zone formed at different circumferential portions thereof. The filter is located on a lower face of and positionable in a circumferential direction relative to a cylindrical light conducting member which surrounds a manually operable knob mounted for rotation relative to an operation panel. A light source is located below the light conducting member so that light emitted from the light source is transmitted to an upper end face of the operation panel by way of the filter and the light conducting member. The distribution of the light passing zone and the light absorbing zone of the filter is selected suitably so as to attain desired uniform illumination at the upper end face of the operation panel.
An illuminating device for an electric part, comprising an operation panel, a knob mounted for manual rotation relative to said operation panel, a cylindrical light conducting member located around said knob, a light source located below said light conducting member, said light conducting member transmitting light emitted from said light source to an upper face of said operation panel, and an annular filter located on a lower face of said light conducting member and having thereon a positioning means for positioning said filter in a circumferential direction relative to said light conducting member, said filter having a light passing zone and a light absorbing zone formed at different circumferential portions thereof.
Dependencies are inferred from the claim text.