Browse Prior Art Database

CRT Pincushion Distortion Corrector Surface

IP.com Disclosure Number: IPCOM000073399D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Underhill, JA: AUTHOR

Abstract

A cathode-ray tube face plate surface is designed to permit distortion free photography without requiring means for cathode-ray tube pincushion distortion correction in the deflection system or in the optics system.

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CRT Pincushion Distortion Corrector Surface

A cathode-ray tube face plate surface is designed to permit distortion free photography without requiring means for cathode-ray tube pincushion distortion correction in the deflection system or in the optics system.

Cathode-ray tube displays are distortion free on a spherical surface whose center coincides with the center of deflection. However, photographic lenses are normally designed to transpose planes into planes with minimal distortion. The position photography of cathode-ray tube displays requires either flat face tubes with means for correcting pincushion distortion or the design of special lenses.

The drawing shows that there exists a surface 1 between the sphere 3 whose center is at the center of deflection and a plane 4, tangent to the spherical surface at the center of deflection on the optical axis 6. This surface is loci 2 of the points of intersection between the extension of the uncorrected electron beam vector 8 and the principal optical ray 5 through the point that would be displayed on a pincushion distortion corrected flat face tube. The distance 7 from the surface 1 along the optical axis 6 is the front conjugate of the photographic lens.

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