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:
Oct. 18, 1994
Filed:
Mar. 22, 1993
Sony Corporation, Tokyo, JP;
Abstract
An image developing apparatus using a laser beam source to produce an original plate for producing a master disk of an optical type recording disk such as video disk and the like. A disk base plate 3 formed thereon with an exposed optically sensitive film 2 is rotated while developing solution 6 is supplied on the optical sensitive film 2 to remove the exposed parts of the film. To monitor the development, a laser beam 8 from a laser beam source 7 is irradiated on an exposed portion of the optical sensitive film 2 which is being dissolved and zero and first order diffraction light 9 and 10 are detected by first and second detectors 11 and 12. Light amount control element 13 are provided to maintain constant the detected level of zero order light by controlling the laser, and the first order light is used to detect a stop time for the development. Stabilization of the zero order light eliminates fluctuations from external sources such as dust, mist etc. The incident light may be controlled by the control element 13 either directly if a semiconductor laser is used or by using a modulator in the light path if a gas laser is used. The semiconductor laser may have a short coherence length which reduces fluctuations caused by multiple interference effects within the glass disk base plate 3 whose thickness can vary.