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High Ambient Light Projection System

IP.com Disclosure Number: IPCOM000075078D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Schreiber, DE: AUTHOR

Abstract

Optical projection systems employing transparent viewing screens are used to permit viewing objects too small to be observed easily by the naked eye. Their use in areas of high-ambient light is restricted since this light tends to wash out the projected image.

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High Ambient Light Projection System

Optical projection systems employing transparent viewing screens are used to permit viewing objects too small to be observed easily by the naked eye. Their use in areas of high-ambient light is restricted since this light tends to wash out the projected image.

A projection system can be used in areas of high-ambient light by changing the light source and viewing screen in the following manner. The transparent viewing screen 1 is constructed in the manner detailed below, the object 2 to be projected is illuminated with ultraviolet light 3 and the image 4 focused on layer 6. It is thus possible to view the image from the side of the screen opposite to that from which it is being projected. However, light coming from the viewing side of the screen is absorbed by layer 5 or 7 and thus does not wash out the projected image.

The three-layer projection screen comprises an ultraviolet transmissive- visible absorbing layer 5; an ultraviolet-to-visible fluorescent layer 6 which is transparent to visible light; and an ultraviolet absorbing-visible transmissive layer


7.

The property of absorbing light incident on the viewing screen from the viewed side permits the use of viewing screens without a hood and their mounting at any angle, while still maintaining a high-contrast image.

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