Optics: image projectors – Miscellaneous
Patent
1988-02-12
1989-11-14
Harrian, Harry N.
Optics: image projectors
Miscellaneous
353DIG3, 353119, G03B 2120, G03B 21132
Patent
active
048803030
ABSTRACT:
An overhead projector comprises a housing the upper side of which is closed by a transparent writing plate under which there is a Fresnel lens. A lamp in the housing is provided with a cold light reflector and a condenser lens for directing light upwardly through the Fresnel lens and writing plate. A projection head mounted above the writing plate on a support arm extending up from the rear side of the housing and comprising an objective lens and a deflection mirror directs the light received from the lamp through the Fresnel lens and writing plate onto a projection screen. A liquid crystal display in a frame hingedly mounted on the rear side of the housing can be swung between an operative position overlying, but spaced from the writing plate and an idle position up against the support arm where it is held by a magnet. The liquid crystal display is controlled by a computer disposed in the housing and fed from a common power supply for the lamp and a ventilating fan located in the housing for cooling the lamp, computer and liquid crystal display. The support arm is hinged so that it can be swung down to a travel position overlying the liquid crystal display and may be recessed on its forward side to accommodate the liquid crystal display.
REFERENCES:
patent: 2852980 (1958-09-01), Schroder
patent: 3807850 (1974-04-01), Ozeki
patent: 3837738 (1974-09-01), Kato
patent: 4338006 (1982-07-01), Ozeki
patent: 4453810 (1984-06-01), Curiel
patent: 4613207 (1986-09-01), Ferfason
Burns Robert E.
Harrian Harry N.
Lobato Emmanuel J.
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