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Projection System for Continuous Film Transport

IP.com Disclosure Number: IPCOM000079225D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Muehlemann, A: AUTHOR

Abstract

Two spherically corrected lens systems L1 and L2 are shown in Fig. 1 with their axes mutually offset in parallel. Within the object space of L1 there is an object 0 at the focal distance from the lens. Rays passing through the same object point are parallel within the image space of L1. Lens L2 has the inverse effect. Within the image space of L2, a real image P of the object 0 is formed at the focal distance of L2. The offsetting of the lens axes does not have any influence on the image P, since the rays through the same object point are parallel between the lenses.

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Projection System for Continuous Film Transport

Two spherically corrected lens systems L1 and L2 are shown in Fig. 1 with their axes mutually offset in parallel. Within the object space of L1 there is an object 0 at the focal distance from the lens. Rays passing through the same object point are parallel within the image space of L1. Lens L2 has the inverse effect. Within the image space of L2, a real image P of the object 0 is formed at the focal distance of L2. The offsetting of the lens axes does not have any influence on the image P, since the rays through the same object point are parallel between the lenses.

If the object 0 is replaced by a moving film frame, it is necessary for lens L1 to follow the frame synchronously in order to obtain a standing image P. Fig. 2 shows lens L1 in a rotatable arrangement about fulcrum C with the film guided along a concentric path. The rotation is compensated with a mirror M.

The projection time for each individual film frame corresponds at maximum to the transit time for twice the frame height F. Accordingly, the maximum angle of rotation is Beta = F/2 R Pi [/o/], where R is the curvature of the film about fulcrum
C.

At the start of projection, the elements are at the positions designated F1, L1 and M, respectively. After the film has moved through the angle Beta, the elements assume positions F1', L1' and M', respectively. As one frame has moved to F1', the next frame occupies position F1, and mirror M will now have to r...