US1482119A

US1482119A - Means for recording and reproducing sound

Info

Publication number: US1482119A
Application number: US423276A
Authority: US
Inventors: Forest Lee De
Original assignee: FOREST PHONOFILM CORP DE
Current assignee: DE FOREST PHONOFILM Corp; FOREST PHONOFILM CORP DE
Priority date: 1919-09-18
Filing date: 1920-11-11
Publication date: 1924-01-29
Anticipated expiration: 1941-01-29

Description

' L. DE FOREST MEANS FOR RECORDING AND REPRODUCING SOUND Original Filed Sept. 18, 1919 m 0 OUWNTQR N Y ATToR i jgaM Patented Jan. 29, 1924.

UNITED STATES PATENT OFFICE.

LEE DE FOREST, OF NEW YORK, N. Y., ASSIGNOR T DE FOREST PHONOFTLM CORPORA- TION, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE.

MEANS FOR RECORDING AND REPRODUCING SOUND.

Original application filed September 18, 1919, Serial 1T0. 324,683. Patent No. 1,446,246, dated February 20,

' 1923. Divided and this application filed November 11, 1920. Serial No. 423:276.

T 0 all whomz't may concern Be it known that I, Len on F'onns'r, a citizen of the United States, and a resident of New York, in the county and State of New York, have invented a certain new and useful Improvement in Means for Recording and Reproducing Sound, of which the following is a specification.

This invention relates to making a record of sound waves suitable for reproduction from the record so made and is directed to the subject-matter divided from my co-pending application U. S. Serial No. 324,683,

filed September 18th, 1919, issued 'as Patent No. 1,446,246,'Feb-. 20,1923.

The object-of the invention is to provide an electrically controlled means for recording sound. z y

. A. further obj ect of the invention is to pro- 20 videelectrically controlled means for photographically recording sound.

Further objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, combination location and relative arrangement of parts, together with the novel methods employed in accordance therewith, all as will be more fully herein- 3 after set forth, as shown by the accompanying drawings and finally pointed out in the appended claims.

Referrin to the drawings The sing e figure illustrates a sound recording arrangement embodying my invention.'

In my co-pending application from which the subject-matter of this present case is divided, I have shown and described means for recordingsound waves upon a photographic film, such as an ordinary film employed in motion picture photography, and I have therein set forth and have described that a source of'light may be directly controlled in the intensity, pitch and volume of sound in such; a manner that the fluctuations caused by sound waves in the intensity of light emitted from the source may be photographed upon the film. I

In accordance withv my present invention I employ a small arc lamp 552, preferably consisting of two heavy tungsten ball electrodes 50 and 51, separated by a small gap,

for example, 0.5 millimeter, mounted in the small vessel 52, either evacuatedor filled with some gas, such as nitrogen, mercury vapor, etc, to make the light from such are as rich as possible in ultra violet rays. The light rays from the arc lamp pass through the lens 3 in the usual well known manner and in addition thereto, if desired, through a color filter 4, which color filter is preferably of a dark blue, as I have found that the best results of recording sound waves photographically are thus secured. A photographic film 7 is passed by the lens and film 3 and 4 respectively in the usual well ktnowln manner and the light emanating from the lamp is recorded on the film, preferably in the nature of a minute ray ob tained from a pin point aperture or focused to a point by a lens. I energize the arc lamp 552' from a source of high frequency current, the frequency of which must be well above the audible limits and modulate the high frequency currents supplied the arc lamp with alternating or pulsating currents set up by and in accordance with sound waves. For example, but to which I do not desire to be limited or restricted, the high frequency currents may be supplied to the arc lamp by oscillion is shown at and comprises the usual plate electrode 61 and grid electrode the oscillion system illustrated, wherein the nected at its terminals to the respective balls I 50 and 51 of the small arc lamp 52. Condensers 66 are shunted around the inductance '64 and a tap connection 67 is provided between the oscillating circuit thus formed and the. filament electrode 63 including therein an impedance coil 68 and a source of current 69, preferably shunted by a condenser 70. An impedance coil is likewise interposed between the source 69 and the filament electrode. The foregoing is briefly a well-established and now a well-known form of high frequency generation circuit forming the subject-matter of separate patents and applications. The alternating or pulsating currents produced by the microphone 5, which is included in circuit with a current source 6 and one coil 17 of a transformer, the othercoil 18 of which is included in the input circuit of an audion amplifier 90, and thus amplified are supp-lied by the output circuit of the audion amplifier 90 to the transformer coil 91 included therein, and thence to the transformer coil 92 in cluded in the grid filament circuit of the oscillion 60, thereby effecting a modulation of the high frequency oscillations generated by the balance of the oscillion systems, and the modulated high frequency oscillations vary the degree of brilliancy of light emitted fro-m the are light by the unmodulated high frequency currents, which variations are proportional in every respect to the original modulating audible frequency alternating or pulsating currents in the microphone circuit. The application of the foregoing principles are many and while I have shown and will now described its application to motion picture photography, to thereby obtain a talking moving picture, I wish it to be understood that I do not desire to be limited or restricted in this respect as this particular application has been selected for the purposes of illustrating the invention involved.

It willthus be apparent that I have provided means which will enable making a permanent record not only of plays \but of all talking, singing, or other sound wave producing parts of the plays and enable the reproduction of the same with perfect synchronism inasmuch as they are on the same record or film in proper relation, relative to each other. In the drawing I show diagrammatically at 10 a motion picture camera through which the motionpicture film 7 passes intermittently in the usual well known manner. I provide a suitable loop 11 in the passage of the film and on one side of the loop I subject the film to the sound controlled light rays, the sound for controlling which is produced by the actors, musicians, or the like, wh1ch are being photographed. The loop which is provided between the sound recording devices and the camera or light recording devices is to enable the film 7 to pass continuously by the lens 3 as distinguished from the intermittent feed of the film past the camera aperture 3 for the obvious reason of maintaining the sound record as a continuous record. The relative speed of travel of the film 7 past the sound lens 3 and past the camera aperture 3 can easily be/ regulated in any well known manner, such as at present employed in the motion picture photography art for making and maintaining speed loops, it being understood that a similar loop is maintained in the film when a reproduction of the record thereon is obtained.

Many modificationsand changes in details will occur to those skilled in the art without departing from the spirit and scope description and the illustrations used in connection therewith regarded in the illustrative sense rather than in a limiting sense.

Having now described and illustrated my invention and having set forth and shown a structure. embodying the principles thereof, what I claim as new and useful and of my own invention, and desire to secure by Letters Patent is 1. The vcombination with an alternating current lamp, 1 cans for continuously supplying an alternating current to said lamp the periodicity of which is above the audible limits to effectively maintain said lamp a constant source of light, and sound controlled means for varying said current.

2. The combination with an alternating current lamp, means for continuously supplying an alternating current to said lamp the periodicity of wh1ch is above the audible limits to effectively maintain said lamp a constant source'of light, and means for va-v rying the alternating currentso supplied by and in accordance with sound controlled alternating currents the periodicity of which is within the audible limits.

3. The combination with an alternating current lamp, an oscillion for supplying high frequency oscillations to said lamp to effectively maintain said lamp a constant source of light, and sound controlled means for modulating said high frequency oscillations.

4. The combination with an alternatin current lamp, an oscillion for supplying high frequency oscillations to said lamp to effectively maintain said lamp a constant source of light, and means for modulating said high frequency oscillations by and in accordance with sound waves to produce corresponding modulation in thelight emitted bylsaid lamp.

5. cans for photographically recording the sound Waves, comprising an electrically lighted lamp, means for constantly supplying high frequency oscillating current to sand lamp to light the same, means for controlling said lamp by and in accordance with sound waves, and means for directing the light from said lamp to a sensitized element.

6. Means for photographically recording the sound waves, comprising an electrically lighted lamp, means for constantly supply-- ing high frequency oscillating current to said lamp to light the same, means for controlling said lamp by and in accordance with low frequency currents, and means for directing light rays from said lamp to a sensitized element.

minous gas discharge device, means for con stantly maintaining said'device efiectivel luminous, and means for varying the luminosity of said device by and in' accordance with sound waves, and means for directing the light from'said device to a sensitized element.

8. Means-"for photographically recording sound waves comprising an enclosed luminous gas discharge device, means for constantly maintaining said device cfiectively luminous, and means for varying the luminosity of said device by telephone currents, and means for directing 'the light from said device to a sensitized element.

9. The method of photographically recording sound which comprises varyin the luminosity of an effectively constantl Eminous enclosed gas discharge device hy in accordance with sound waves.

10. The method of photographically recording' sound which comprises varying the luminosity of an efi'ectively constantly luminous enclosed gas discharge device by and and in accordance with telephonic currents.-

In testimony whereof I have hereunto set my hand on this 3d day of November,

LEE DE FOREST.