The Singer Company

Telex Communications, Inc.

William T Daly

Boris Gelman

John Vernon Landau, Jr

Marvin I Mindell

Arthur B Price

William R Sanderson

J David Garland

An automatic focusing system for a slide projector which utilizes a pair of photocells is provided with a non-linear response characteristic to introduce a change in the sensor balance point when a glass covered film slide is projected as opposed to when an open film slide is projected. Accordingly, glass covered film slides and open film slides can be randomly intermixed without changing the projector focus.

Automatic focusing system

A microprocessor is utilized to monitor and control the operation of an image projector and a magnetic tape cassette player. Inaudible cueing tones recorded on the tape allow the recorded narrative to be kept in synchronization with the image projected. A sync counter within the microprocessor keeps track of the amount and direction by which the image and tape are out of synchronism. The microprocessor controls a visual indication to the operator that shows the direction in which the tape must be moved to regain synchronization. When the tape is moved forward to achieve synchronization, the microprocessor will stop the tape after the cue pulse that precedes the narrative for the associated image. When the tape is moved in the reverse direction to achieve synchronization, the microprocessor will stop the tape just beyond the cue pulse at the beginning of the desired narrative. Accordingly, when the tape player is placed into the play mode, the microprocessor will mute the audio until that cue pulse is sensed and inhibit the normal film advance for that cue pulse. A frame counter within the microprocessor keeps track of the amount and direction by which the projected image has moved from a reference or saved image location. Return to the reference image and associated narrative is initiated by the operator. Once initiated, the image bearing means is automatically returned to the position that projects the reference image under the control of the microprocessor which also visually indicates to the operator the direction the tape must be moved to synchronize the narrative with the reference image. When moved to the proper location, the tape is stopped by the microprocessor. The image which constitutes the reference image can readily be changed by the operator.

Microprocessor controlled filmstrip projector

Growing community of inventors

Rochester, NY, United States of America

William T Daly