Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1987-12-14
1989-06-13
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250578, H01J 314, H01J 516, H01J 4014
Patent
active
048395145
ABSTRACT:
A reading surface of a document is illuminated by a light source, and a light beam reflected on the reading surface is reflected on a reflecting mirror. Then, the reflected light beam is guided in such a direction as to pass in the vicinity of a light shielding plate for shielding the constitutional elements from the light. A lens is located near the light source at a position where the light beam guided in the above direction is allowed to pass. A shading correcting device is made up of a first shading correcting portion formed by a part of the light shielding plate and a second shading correcting portion formed in a body case for holding the constitutional elements. The shading correcting device is designed to restrict a more quantity of light of the light beam incident upon the lens at a portion nearer to an optical axis of the lens. A photoelectric correcting device is provided in a position where the light beam passing through the lens is focused. As a result, photoelectric converting elements in the photoelectric converting device receive an equalized quantity of light of the light beam. A part of the shading correcting device for equalizing the quantity of light of the light beam incident upon the photoelectric converting means is formed by utilizing the light shielding plate. Accordingly, the number of parts may be reduced, and the assembling work may be simplified.
REFERENCES:
patent: 4205349 (1980-05-01), Kawazu et al.
patent: 4644159 (1987-02-01), Miura
patent: 4677494 (1987-06-01), Sue
patent: 4682042 (1987-07-01), Igarashi
Mine Kazunori
Murakami Keisuke
Tago Mamoru
Urata Hiromasa
Chatmon Eric F.
Nelms David C.
Tokyo Electric Co. Ltd.
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