US1795751A - Apparatus and method for copying photographically-recorded sound records - Google Patents

Description

March 10, 1931. J BALSLEY 1,795,751

APPARATUS AND METHOD FOR COPYING PHOTOGRAPHICALLY RECORDED SOUND RECORDS Filed Dec. 5, 1928 2 sheds-sheet 1 AMPLIFIER March 10, 1931. J. R. BALSLEY 1,795,751

APPARATUS AND METHOD FOR COPYING PHOTOGRAPHICALLY RECORDED SOUND RECORDS Filed Dec. 5. 1928 2 Sheets-Sheet 2 IIMPLIHER Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE JAMES B. BAIJ SLEY, OI NEW YORK, N. Y., ASSIGNOB TO FOX CASE CORPORATION, OI

' NEW YORK, N. Y., A CORPORATION 01? NEW YORK APPARATUS AN D METHOD FOR COPYING PHOTOGBAPEIOALLY-BEOOBDED RECORDS Application filed December 5, 1928. Serial No. 824,018.

This invention relates to a certain new and improved apparatus and method for copying a hotographically recorded sound record,

hotographically recorded sound records are of at least two types. First, a variable density record, and second, a variable area record, and the main object of this invention is the production of an apparatus by means of which an exact duplicate of the original [0 record, whether it be of the variable area or the variable density type, can be produced.

Further, the apparatus provides a means for producing an equivalent variable density record'from a variable area original or for producing an equivalent variable area record from a variable density original.

Further, the apparatus and method of this invention permits the production of more accurate copies or equivalents in that the film upon which the record is to beproduced may be run at comparatively low speed considerably below the natural period of the light valve used, and permits the use of simple light valves not suitable for high frequencies,

such as a common oscillograph element, or

as here illustrated, a galvanometer.

Other objects and advantages relate to the details of the structure and the form and relation of the parts thereof, all as will more fully appear from the following description taken in connection with the accompanying draw-- in s, in which:-

igure 1 is a diagrammatic illustration of an apparatus for producing a variable density record which is substantially the exact duplicate or equivalent of either a variable density or a variable area original record.

Figure 2 illustrates a section of film provided with a variable area record.

Figure 3 is a similar view of a variable density record.

Figure 4 diagrammatically illustrates an apparatus for producing a variable area 5 record substantially the exact duplicate or equivalent of a variable area or a variable density record,

Figure 5 is a further diagrammatic illustration of a portion of an apparatus for pro- 0'0 ducing a .variable area record.

Fi re 6 is a section of a film having a varia le density record thereon.

Fi re 7 is a section of a film having a varia 1e area record thereon.

The system requires that the developed original film and the unexposed film on which the copy is to be made should be run through the machine at exactly the same speed, and this may be accomplished as hereinafter described by moving the films by identical sprockets on the same shafts or any other convenient means of synchronizing the parts.

As illustrated in Figure 1 the film 1- bears an original record of light variations corresponding to sound wave variations here- 'in termed a sound record. Any suitable means may be provided for focussing or producin upon this film a line of light of a size and s ape substantially identical with the size and shape of the line of light utilized in the production of the sound record. This straight beam of light may be produced as shown by focussing the rays of hght from an electric lamp -2 upon a slit -3- in an opaque wall -4- as by means of lens '5--. The slit --3'- may, if desired, be of a diflt'erent size than the desired line of light to which the film 1 is exposed, and its image may be either enlarged or reduced, as desired, by means of a lens or lens system There is here illustrated a wall --7 having a slit -8 therein past which film 1 moves in close relation with the slit but where suitable focussing means is provided as here 5 illustrated, the opaque wall -7-- with its slit of desired size is preferably omitted. The line of light striking the film -1- is modulated in accordance with the sound record upon the film as it is transmitted through the film and falls upon the photo-electric cell or other light reactive element 9- included in circuit with the filament -10- and grid 11 of an electron discharge device 12-.

As illustrated, a resistance -13 may be 05 inserted across the source of potential -14- and the light reactive element -9- and a further resistance --11- and source of potential 15- may be inserted across the filament and grid of the electron dis- 100 charge device. A condenser -16- is positioned, as shown, if desired.

The output circuit of the electron discharge device -12 is connected through any desired number of stages of amplification with a source of light 17-, a source of potential 48 being provided for maintaining the source of light in' light-emitting condition.

This source of light may be in the form of a bulb --18 containing a pair of spaced electrodes 19 and 20 and a suitable ionizable gas such as helium or helium with a small percentage of nitrogen, the gas pres sure being preferably such that at operating voltage an intense light is concentrated about the cathode, and this glow is the light utilized for producing a photographic record.

The light from this source of light -1'7- passes through a narrow elongated slit 21 of the same size as the line of light to which film 1 is exposed, and falls upon the unexposed film -22. As the film 22- is running at the same speed as the film 1- for the reason that sprockets -23-- and +24- are driven at the same speed, and are of the same size, there will be produced upon film 2Qr a variable density sound record which is either identical with the sound record upon film -1- if that record he a variable density one, or will be the exact equivalent for reproducing sound if the sound record upon film'1 is a variable area record. 4

In other words, the film 1 may include either the variable area record A of Figure 2, or the variable density record B of Figure 3, and in either case the variable density record B will be produced upon film 22' which is either an exact copy or a sound equivalent of the record upon the film -1-.

In Figures 4 and 5 an apparatus is disclosed for producing a varia le area record which is either a copy or an equivalent of a variable area or a variable density sound record. The film -1 in this disclosure may, as stated, include either the variable density record B of Figure 6 or the variable area record A of Figure 7 The means illustrated for focussing a line of light upon this film is the same as'that disclosed in Figure 1, and the light reactive device --9- and its circuits to the galvonometer -30- may be the same as the circuits connecting light cell -9- with the source of light 17-. 1

The structure of Figure 4 differs from that point in that a type of apparatus is shown illustrative of a means for producing a variable area sound record. In such case a mirror -3lmay be attached for movement with the galvonometer shaft -32-. A source of a. line of light is utilized, as for instance the straight line filament lamp -33-, the image of which filament is focussed by lens or lens system -45 upon the mirror -31-',

and this mirror is so positioned with respect to a slit 43-- in an opaque wall 44- as to reflect the line of light focussed upon it through said slit. Oscillation of mirror 31- in accordance with. galvonometer variations conforming to electrical variations in the circuit leading from the light reactive device causes more or less of the length of the line of light to pass through the slit 33-, thereb producin a variable area sound record and in li e manner, as described in connection with Figure 1, the film --22 moves past slit 43, at the same speed as the film 1- moves past the slit 8-, the respective films being driven. by

similar sprockets 23 and 24- mounted upon the same shaft.

It will be apparent that with this ap aratus, the film -1-- may be either a varia le density sound record or a variable area sound record, and that in either case there will be produced upon film 22- a variable area record A, either an exact copy of a film -1 including a variable area record, or. elsea variable density record B will be produced upon film 22- which is the equivalent for sound. production of the sound record upon the film -1.

As before stated, an important feature of this invention resides in thefact that the films -1 and --22., in order to make the copy or the equivalent record in accordance with this invention, can be run at a speed much slower than the speedat which film 1- was run in the production of the ori inal record thereon, and as a result a simp e light valve not suitable for high frequencies may be used, such as a common oscillograph element, an illustrative" apparatus being here shown as a galvonometer and mirror actuated thereby and such light valve need not have a flat frequency characteristic above sixty cycles if 9000 cycles is the highest frequency to copy, and'the copy is made at 1/150th, the

speed at which the original record 1-- was made.

Altho .no exact dimensions of the line of light to be focussed upon the films need be given, as considerable variation is possible, dependent upon film speed and frequencies to be copied, etc., yet this beam is preferably as narrow as practicable, and must be small compared to the length of the film covered by a half cycle of the highest frequency re corded on the original, for example 2- If 9000 cycles per second is the highest frequency deslred on the copy and the original sound recordwas made on a film run at 90 feet per minute, one-half cycle will take up .001 of an inch of the length of the film. The beam of light should thenbe less than .0003 of an inch wide. e I

'Altho I have shown and described a specific apparatus and details of embodiments of the invention as illustrative of apparatus for carrying out the same, I do not desire to restrict myself to the particular apparatus disclosed or to the details of form, arrangement or construction of the same, as various changes and modifications may be made within the scope of the appended claims.

I claim: 1. An apparatus for producing a photographic sound record comprising a film havmg a variable area sound record thereon, means for directing a line of light upon such record, a light reactive element exposed to the light transmitted through said record, a sensitized element and means for producing on said sensitized element a variable density sound record capable of exactly reproducing the sound photographed upon said film including a lamp adapted to emit light rays of variable intensity in accordance with varig0 ations in the light rays to which said sensitized element is exposed. y 2. An apparatus for producing a photographic sound record comprising a film having a variable area sound record thereon, means for directing a line of light upon such record, a light reactive element exposed to the light transmitted through said record, a sensitized element, means for producing on said sensitized element, a variable density sound record capable of exactly reproducing the sound photographed upon said film 'ineluding a glow lamp adapted to emit light rays of variable intensity in accordance with variations in the light rays to which said sensitized element is exposed, and means. for moving said film and said sensitized element at the same speed.

3. An apparatus for producing a photographic sound record comprising a film hav- 40 ing a variable area sound record thereon, means for directing a line of light upon such record, a light reactive element exposed to. the light transmitted throu h said record, a sensitized element, means or producing on said sensitized element a variable density sound record capable of exactly reproducing the sound photographed upon said filmincludin a glow lamp adapted to emit light rays 0 varlable intensity in accordance with variations in the light rays to which said sensitized element'is exposed, and meansfor moving said film and said sensitized element in synchronism at a speed substantially slower than the'speed at which the film'was moved when the sound recordwas'produced onsaid film. '1" i In witness whereof I have hereunto set my hand this 13th da of November, 1928.

, AMES R. BALSLEY.

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