US2097758A - Reproduction of sound - Google Patents

Description

Nov. 2, 1937.

a. 1.. DlMMlCK REPRODUCTION OF SOUND Filed Jan. 19; 1955 ATTORNEY Patented Nov. 2, 1937 PATENT OFFICE REPRODUCTION OF SOUND Glenn L. Dimmick, Haddonfield, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application January 19, 1935, Serial No. 2,460

5 Claims.

This invention relates to the photographic recording and reproducing of sound, and has for its principal object the provision of an improved apparatus and method of operation whereby types of sound records heretofore capable of being reproduced only in different types of devices may be reproduced by the same device.

In my copending application Serial No. 610,302 filed May 9, 1932, is disclosed a sound record on which the positive and negative undulations are recorded on separate tracks spaced from one another so as to permit their images to be focused separately on difierent light responsive elements. As pointed out in the aforesaid application, this spacing of the component parts of the record has the advantage that fogging between peaks at high frequency is avoided, background noise is eliminated, the tendency of an alternating current exciter lamp to produce hum in the reproduced sound is neutralized and the development of the film is simplified.

A further object of this invention is to provide an apparatus operable to reproduce sound records irrespective of whether the positive and negative undulations are recorded together or separately on tracks spaced apart from one another. In accordance with the invention, the light beam modulated by the sound-record is split into different components and these components are applied to the same or to different light sensitive elements depending on whether the negative and positive sound impulses are recorded on the same or difierent tracks or areas.

The invention will be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out by the appended claims.

The singlefigure of the drawing is a diagrammatic illustration of a sound reproducing apparatus embodying the invention.

This apparatus includes an exciter lamp Ii] from which light or" substantially constant intensity is applied to the sound record of a film ll through an optical system I2. The sound recrd of the film Il may be either the push-pull type of record disclosed by the aforesaid application or a record having all the sound components recorded on a single track. In either case the light beam acoustically modulated by the record of film or strip II is transmitted through lenses and is split by lenses l4 and I5 into two separate beams one of which is applied toa stationary reflector l6 and the other of which is applied to an adjustable reflector ll.

With the reflectors l6 and I! in their full-line 5 illustrated positions one of the acoustically modulated light beams is reflected by the stationary reflector Hi to the cathode I 8 of a light sensitive device and the other light beam is reflected by the adjustable reflector I! to the cathode 2! of 10 the device [9. From the device l9, acoustically modulated current is supplied to a utilization apparatus such as a loud speaker, through means including an electrical source 22 connected to the lead of anode 23, a transformer 24, suitable amplifiers (not shown) etc. Under these conditions, a record having its negative and positive impulses separately recorded on tracks spaced from one another is reproduced with all the advantages pointed out above.

When a record having all the sound components recorded on a single track is to be reproduced, the mirror His shifted to the dotted line position and the two light beams are reflected to the cathode I8 and converted into corresponding electrical impulses in a manner too well understood to require further description. It will be apparent that any suitable type of electrical connection other than that illustrated may be utilized and that additional component lightbeams may be controlled in the manner herein described.

I claim:

1. The combination of means for producing a plurality of acoustically modulated light beams, a light sensitive device provided with a plurality of cathodes, means for directing selected portions of said beam, separate cathodes and means for selectively directing said portions to a single cathode.

2. The combination of means for producing a plurality of acoustically modulated light beams, a light sensitive device provided with a plurality of cathodes, and means including a stationary reflector interposed in the path of one of said beams for directing said beam to one of said cathodes and an adjustable reflector interposed in the path of another of said 'beams for directing said beam to the same cathode or to a different cathode of said device.

5. In combination, means for directing a beam of light through a film sound track, means for dividing said beam into two portions, and means for alternatively directing said portions either onto two cathodes of a light sensitive device connected in a push pull circuit or onto only one cathode thereof, whereby either a push pull sound track or an ordinary sound track may be reproduced for the same apparatus.

GLENN L. DIMNHCK.

- CERTIFICATE OF CORRECTION.

Patent No. 2,097,758. November 2, 1957,

GLENN L. DIMMICK.

It is hereby eertified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 1, second column, line 58, after "beam strike out the comma and insert instead the word "to; and that the said Letters Patent should be read with this correotion therein that the same may conform to the record ofthe case in the Patent Office. a i

Signed and sealed this 1st day of February, A. D. 1958.

Henry Van'Arsdale, Acting Commissioner of Patents.

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