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US 4,053,904 AGranted
Overlap and overscan exposure control system
AssigneeGTE Sylvania Incorporated
InventorsG. Norman Williams, Mahlon B. Fisher
Life of this patent
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AssigneeGTE Sylvania Incorporated
InventorsG. Norman Williams, Mahlon B. Fisher
Estimating the term…
In an optical scanning exposure system for manufacturing cathode ray tubes having a faceplate with an inner surface layer of photosensitive material and an adjacent apertured mask wherein the exposure system includes a light source providing a light beam, an angle of incidence deflector means for deflecting the light beam at an angle related to the angle of incidence of an electron beam, means for imaging the light beam, and a means for scanning the light beam in a predetermined fashion over the apertured mask to expose the photosensitive material, a control system having a means for storing information representative of the angle of incidence of a light beam and the rate of scanning of a light beam between a matrix of positional locations on the faceplate, a scan rate means for controlling the rate of horizontal and vertical light beam scanning, an encoder means providing light beam positional information to the storage means, and an angle of incidence control means for activating the angle of incidence deflector means in accordance with angular information of the storage means. Other aspects of the invention include controlling the integral with respect to time of the light beam intensity to effect uniform photosensitive material exposure, controlling movement of the effective light beam source to control the size and shape of the exposure area, and controlling the overlapping and overscanning of the light beam scanning to minimize stripes of unexposed photosensitive material and to provide uniform exposure at the edges of the faceplate.
In a method for controlling an optical scanning exposure system for exposing a photosensitive layer on a faceplate of a cathode ray tube wherein the electrical control system includes an angle of incidence and scan rate memory storage means, scanning means, and an angle of incidence control means and the method for controlling the optical scanning exposure system includes the steps of activating the scan rate means to cause light beam scanning of the faceplate of the cathode ray tube, applying signals representative of the positional location of a light beam to the angle of incidence and scan rate memory means to derive signals representative of the angle of incidence of an electron beam, coupling the signals representative of the angle of incidence of an electron beam to said angle of incidence control means, and coupling signals representative of said desired rate of scan to said means for effecting horizontal and vertical scanning, the improvement comprising the added step of:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
By photographic processes: devices for carrying out the processes, e.g. light houses
Electric discharge tubes or discharge lamps
Term ended 11 Oct 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
A concurrently filed application entitled "Optical Scanning Apparatus for Photolithography of a Color Cathode Ray Tube Having An Aperture Mask" bears U.S. Ser. No. 699,109 and is filed in the name of John Schlafer. Therein, a method and apparatus for fabricating a cathode ray tube by an optical scanning technique is provided and fully detailed.
Also, concurrently filed applications directed to Optical Scanning Apparatus include: "Control System For An Optical Scanning Exposure System For Manufacturing Cathode Ray Tubes" bearing U.S. Ser. No. 699,045 filed in the name of Thomas W. Schultz; "Exposure Area Control For An Optical Scanning System of Manufacturing Cathode Ray Tubes" bearing U.S. Ser. No. 699.046 in the name of Thomas W. Schultz; "Scanning Rate and Intensity Control For Optical Scanning Apparatus" bearing U.S. Ser. No. 699,047 filed in the name of Thomas W. Schultz; and "Optical Scanning Apparatus and Method For Manufacturing Cathode Ray Tubes" filed in the names of G. Norman Williams, Robert F. Wilson, and John Schlafer bearing U.S. Ser. No. 699,110.
The present invention relates to a system for controlling an optical scanning exposure system suitable to the manufacture of cathode ray tubes and more particularly to a control system for storing information representative of the angle of incidence of a light beam at a matrix of points and scan rate information intermediate the points of the matrix and for applying the stored information to an optical scanning system to effect a proper rate and angle of scanning and deflection of a light beam which is imaged on a layer of photosensitive material affixed to the faceplate of a cathode ray tube.
FIG. 1 is a block diagram illustrating a control system for an optical scanning exposure system suitable to the manufacture of cathode ray tubes;
FIG. 2 is a symbolic illustration to assist in the explanation of the control system of FIG. 1;
FIG. 3 is an explanatory diagram for explaining one form of interpolator apparatus of FIG. 1; and
For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in conjunction with the accompanying drawings.
Referring to the drawings, FIG. 1 is a block diagram illustration of a system for controlling an optical scanning exposure suitable to the manufacture of cathode ray tubes. As detailed in the cross referenced application, an optical scanning exposure system includes a light source 7, preferably a laser, which directs a light beam 9 onto a beam forming optics configuration 11. The formed light beam is applied to an angle of incidence deflector means 13 which alters the path of the light beam in a manner affecting its angle of arrival at the CRT faceplate but does not seriously alter the position at which it strikes the faceplate.
This angular altered light beam is applied to an imaging optic system 15 wherein the light beam is correctly imaged and applied to a horizontal and vertical scanning means 17. The horizontal and vertical scanning means 17 is directed in a predetermined horizontal and vertical scanning path and causes the light beam to scan an apertured mask 19 adjacent a layer of photosensitive material 21 affixed to the inner surface of the faceplate 23 of a cathode ray tube.