Browse Prior Art Database

Uniaxial Projection System

IP.com Disclosure Number: IPCOM000093304D
Original Publication Date: 1967-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Krembs, GM: AUTHOR [+3]

Abstract

In conventional projection systems in which optically stored images are superimposed on electron optical images generated on a CRT face-plate, the presentation is distorted. This is because the images are normally projected at different angles.

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Uniaxial Projection System

In conventional projection systems in which optically stored images are superimposed on electron optical images generated on a CRT face-plate, the presentation is distorted. This is because the images are normally projected at different angles.

In this system for the uniaxial projection of two images, an image on the face of cathode ray tube 11 is reflected from spherical mirror 13 and projected through a conventional Schmidt projector and corrector lens 17 onto rear projection screen 19 as a dynamic display. The focal point of mirror 13 is the center point 21 of the CRT screen. Front surface mirror 15, positioned in a dead space immediately in front of projector 17, eliminates image ghosts characteristic of other glass beam splitters or reflectors. A static display is projected from object overlay 23, which can comprise a 35 mm film slide, through a command projection lens having two principal points 25 and 27 onto the reflective surface of mirror 15. From here it is reflected onto the projection screen 19. Mirror 13 has an opening in the center portion to permit direct cooling of the CRT surface by a cooling medium such as air blower 29.

In the geometric optics, the distance from the second principal point 27 of compound projection lens 25 to the optical axis of projector 17 must be greater than the radius of mirror 13. In addition, the focal length of lens 17 requires that the throw distance be approximately twice the maximum picture...