CONTINUOUS MOTION APPARATUS FOR TV FILM SCANNING

• US 3,584,148 A
• Filed: 09/11/1969
• Issued: 06/08/1971
• Est. Priority Date: 09/11/1969
• Status: Expired due to Term

• Current Assignee: Flory Robert Earl
• Original Assignee: Flory Robert Earl
• Inventors: FLORY ROBERT EARL
• Application Number:
  US04/857,115
• Time in Patent Office: 635 Days
• US Class Current: 348/97
• CPC Class Codes: G03B 41/06 with rotating reflecting member
• CPC Class Codes: H04N 3/38 with continuously moving film

Abstract

In a television film projection system film having a frame rate less than the television field rate is moved through a film gate at a continuous speed and each frame is illuminated several times by a stroboscopic light operating at the field rate to image the film content onto a photosensitive surface of a television pickup tube. Apparatus including a rotating mirror system disposed in the optical path compensates for the motion of the film between successive stroboscopic light flashes so that each film frame is imaged onto the same photosensitive area of the pickup tube.

Claims

1. In a television film projection system, motion-compensating apparatus for precisely positioning on a storage-type photosensitive electrode of a camera tube during respective vertical-blanking intervals a plurality of momentary light replicas of each of a series of image-bearing frames of a continuously moving motion picture film, said light replicas being produced by light from a stroboscopic light source momentarily actuated by the detection of frame-positionidentifying indicia in a marginal strip of said film adjacent each of said image-bearing frames, said film-motion-compensating apparatus comprising:

a main pair of stationary light reflectors, each having a flat exteriorally reflecting surface and positioned at a right angle to one another symmetrically relative to reference line bisecting said right angle, the reflecting surface of one of said stationary reflectors facing said film and said stroboscopic light source and the reflecting surface of the other of said stationary reflectors facing said camera tube;

at least two auxiliary pairs of light reflectors, each pair having flat interiorally reflecting surfaces positioned at right angles to one another and each of said auxiliary pairs being movable into mutual parallelism of its reflecting surfaces with the reflecting surfaces of said main pair of stationary reflectors, the apices of the right angle formed by the reflecting surfaces of one of said auxiliary pairs of reflectors when mutually parallel to the reflecting surfaces of said main pair of reflectors being differently positioned relative to said reference line than the other of said auxiliary pairs when mutually parallel to the reflecting surfaces of said main pair of reflectors such as to enable said momentary light replicas of each image-bearing frame in different positions to be directed to said camera tube; and

means for moving each of said pairs of said auxiliary reflectors into said mutual parallelism in synchronism with said continuous film movement.

2. In a continuously moving television film projection system in which said television field rate is substantially a multiple of said film frame rate, film-motion-compensating apparatus as defined in claim 1, wherein:

the number of auxiliary pairs of light reflectors is equal in number to said multiple of the film frame rate.

3. In a continuously moving television film projection system in which said television field rate is substantially three times said film frame rate, film-motion-compensating apparatus as defined in claim 2, wherein:

three auxiliary pairs of light reflectors are provided.

4. In a continuously moving television film projection system, film-motion-compensating apparatus as defined in claim 3, wherein:

said main pair of stationary light reflectors are joined to form a unitary structure; and

each of said pairs of movable light reflectors are joined to form respective unitary structures.

5. In a continuously moving television film projection system film-motion-compensating apparatus as defined in claim 4, wherein:

the pairs of light reflectors respectively of said main and auxiliary reflectors are joined at the apices of the right angles formed respectively therebetween.

6. In a continuously moving television film projection system, film-motion-compensating apparatus as defined in claim 5, wherein:

the apex of the right angle formed by a first one of said auxiliary pairs of reflectors is located on said reference line when its reflectors are mutually parallel to said main pair of stationary reflectors to correspond with a film frame position centrally in said film gate;

the apex of the right angle formed by a second one of said auxiliary pairs of reflectors is located at a given spacing on one side of said reference line when its reflectors are mutually parallel to said main pair of stationary reflectors to correspond with a film frame position at a given distance to one side of said central film gate position; and

the apex of the right angle formed by the third one of said auxiliary pairs of reflectors is located at said given spacing on the other side of said reference line when its reflectors are mutually parallel to said main pair of stationary reflectors to correspond with a film frame position at said given distance to the other side of said central film gate position.

7. In a continuously moving television film projection system, film-motion-compensating apparatus as defined in claim 6, wherein:

said given distance is equal to one-third of the height of one of said image-bearing frames longitudinally of said film; and

said given spacing is equal to one-half of said given distance.

8. In a continuously moving television film projection system, film-motion-compensating apparatus as defined in claim 7, wherein:

said three auxiliary pairs of light reflectors are mounted on a turntable having its axis of rotation located on said reference line.

9. In a continuously moving television film projection system, film-motion-compensating apparatus as defined in claim 8, wherein:

said film-frame-position-identifying indicia comprise one sprocket hole for each image-bearing frame;

said film being continuously moved past said gate by a 10 tooth sprocket wheel engaging said sprocket holes and rotating at two revolutions per second; and

said turntable being mechanically linked to said sprocket wheel and rotating at 20 revolutions per second.

10. In a continuously moving television film projection system in which said camera tube has electron beam deflection apparatus locked to an alternating current power supply and is operative to scan light replicas projected onto its photosensitive electrode at the rate of 60 per second, film-motion-compensating apparatus as defined in claim 9, wherein:

said turntable and said sprocket wheel are driven by a synchronous motor energized from said alternating current power supply.

11. In a television film projection system, motion-compensating apparatus for precisely positioning on a storage type photosensitive electrode of a camera tube during respective vertical-blanking intervals a pluRality of momentary light replicas of each of a series of image-bearing frames of a continuously moving motion picture film, said light replicas being produced by light from a stroboscopic light source momentarily actuated by the detection of frame-position-identifying indicia in a marginal strip of said film adjacent each of said image-bearing frames, said film-motion-compensating apparatus comprising:

film-frame-position-identifying means including a source of continuous light, of a color different than the light from said stroboscopic source, directed along a first auxiliary light path to a first dichroic mirror which passes said stroboscopic light and which reflects said continuous light along an optical path of said stroboscopic light through said indicia in said marginal strip of said film to a second dichroic mirror which reflects said continuous light along a second auxiliary light path to photodetecting means when said film is in proper registry with said photosensitive electrode of said camera tube for developing a signal for actuating said stroboscopic light source;

a main pair of stationary light reflectors, each having a flat exteriorally reflecting surface and positioned at a right angle to one another symmetrically relative to a reference line bisecting said right angle, the reflecting surface of one of said stationary reflections facing said film and said stroboscopic light source and the reflecting surface of the other of said stationary reflectors facing said camera tube;

at least two auxiliary pair of light reflectors, each reflector of each said auxiliary pairs having a flat interiorally reflecting surface positioned at a right angle to the other reflector of said auxiliary pair and each said auxiliary pair of reflectors being movable into mutual parallelism of its reflecting surfaces with the reflecting surfaces of said main pair of stationary reflectors;

the apices of the right angle formed by the reflecting surface of one of said auxiliary pairs of reflectors when mutually parallel to the reflecting surfaces of said main pair of reflectors being differently positioned relative to said reference line than the other of said auxiliary pairs when mutually parallel to the reflecting surfaces of said main pair of reflectors such as to enable said momentary light replicas of each image-bearing frame in different positions to be directed to said camera tube; and

means for moving each of said pairs of auxiliary reflectors into said mutual parallelism in synchronism with said continuous film movement.