The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 1982
Filed:
May. 31, 1977
Herbert Schroter, Taunusstein, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
Disclosed is a device for dosing light from a light source in accordance with the intensity of light impinging upon a material to be exposed, comprising: a photosensitive element located in the beam path of the light source, comprising a photoresistor having an ohmic resistance inversely proportional to the intensity of light impinging thereon and providing an output voltage; a capacitor arranged in series with the photosensitive element; means, preferably in the form of a switch bridging the capacitor, responsive to switching-on of the light source for initiating charging of the capacitor; switching means arranged in series with said capacitor for varying the charging time thereof, whereby the exposure time of said material to be exposed can be varied by a predetermined ratio to produce a desired shade of gray; optional means for amplifying the output voltage of the photosensitive element; means for comparing the output voltage of the photosensitive element with a reference voltage to produce an output signal; and means for controlling the amount of light impinging upon the material to be exposed in response to the output signal from the comparing means.