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:
Feb. 14, 1995
Filed:
Nov. 15, 1993
Thor A Olson, Minneapolis, MN (US);
Richard A Keeney, Eagan, MN (US);
Management Graphics, Inc., Minneapolis, MN (US);
Abstract
An imaging system such as an image recorder or scanner is provided with a rearview cathode ray tube. A transparent viewport of optical quality is provided along an optical axis of the CRT which is perpendicular to the CRT faceplate and generally centered with respect to the image area. The electron beam used for scanning the images is placed off-axis with respect to the CRT screen. A deflection control system compensates for spherical distortion and for the keystone effect that results from the off-axis placement of the electron gun. The structure of the present invention eliminates halation, thereby improving the dynamic range and contrast achievable for imaging and/or scanning purposes. The phosphor layer used in the CRT is made substantially thicker than in conventional CRTs, thereby reducing blemishes and improving uniformity, resolution and light output. The partial sharing of electron beam and optical paths enables more compact imaging and scanning systems to be provided.