US1864363A - Recording apparatus - Google Patents

Description

June 2l, 1932. H. J. MCCREARY 1,864,363

RECORDING APPARATUS Filed April 2l. 1930 s wmwllfllr-w/gm ir 33 i i Fig. 5.

Inventor: Harold J. lUIcC'r'eclr'H b5 M14/MW HLS Attorneg.

Patented June 21, v 1932 UNITED STATES PATENT OFFICE ELEcTRIc com- PANY, A CORPORATION 0F NEWYORVK RECORDING APPARATUS Application led April 21,

My invention relates to apparatus for photographically recording electrical variations. More particularly it ,relates to apparatus for making a. photographic record of sound waves on a moving sensitive member. It-is the objective of my invention to provide improved apparatus for this purpose which among other advantages shall be freeof inertia effects and which is thus adapted for the 'recording of high frequency variations.A In accordance with my invention I cause a narrow beam of electrons or cathode rays to be ejected from the evacuated envelope in which they are produced and to be modulated by the variations to be recorded. Through Said cathode rays l pass a member which is sensitive'thercto, such for example as a photographic film.

AMy invention will be better understood from the following description takenl in connection with the accompanying drawing, and its scope willbe pointed out in the appended claims.

Referring to` the drawing, Fig. 1 illustrates one embodiment of my invention adapted for making a. photographic sound record ofthe variable intensity type on a film of the motion picture type; Fig. 2 shows a detail thereof drawn to a larger scale including the Lenard window construction used and a portion of the sensitive film; Fig. 3 shows a fragment ofV a motion picture film having at one side thereof a sound record made by the apparatus illustrated in Fig. 1; Fig. 4 is similar to Fig. 1 but illustrates a modified form by means of which a sound record of the variable width type may be made; and Fig. 5 shows a fragment of a motion picture film having thereon a sound record made by this modified form of apparatus.

In the form of apparatus illustrated by Fig. .1, I have shown the sound pick-up device l, such for example as a condenser microphone, connected through the amplifier 2 to the cathode ray tube 3 which tube is constructed to eject electrons or cathode rays in -a narrow band through which passes the moving film 4, the intensity of the rays being varied in accordance with the sound waves received by the vpick-up device. The tube 3' is 1930. serial no. 446,005.

shown having the hot cathode 6 which'is arranged in the cup-shaped member 7 and to which energy for heating the cathode is supplied by the battery 8 under the control of" the rheostat -9. The anode comprises the metal tube 10 which is sealed in the wall of the tube 3 and extends externally thereof. Suitable means, shown for example as the battery 11, is connected to the anode tube 10 and to the cathode for raising the tube to the proper positive potential to cause the ejection of the cathode rays. The control of the intensity of the ejected rays may be effected in y various ways. In the drawing I have shown it secured by the use of the grid 12'which by connection to the amplifier has its potential varied in the well known manner in accordance with the amplified current variations received from the pick-up device. The outer end head or plate 13 of the anode tubelO is provided with a very narrow opening or slit 14 whose length equals the width of the desired sound track on the film and whose width may, for example, be of the order of one onethousandth of an inch. The slit is shown covered by a piece of very thin metal foil 15, such for example as aluminum foil, which is secured tothe outer face of the end plate 13 as for example by soldering. vThrou h the Lenard windowv thus formed, the catho rays are ejected from the evacuated generetting tube and are caused to engageA the moving sensitive lm 4. This film preferably runs as close as possible tothe foil 15 and may be sup ported and moved in any suitable manner. Asillustrated in Fig. 1,the film is shown as of the motion picture type having sprocket tooth holes 16 and as supported on the roller orvdrum 17 mounted on the shaft 18. The` film should be moved atthe point ofl engagement with the rays with a uniform movement for which purpose the film may be driven at that point by the drum or may be drawn over the drum by other suitable mechanism. In Fig. 3 I have represented the film 4 drawn to a larger scale and as showing Ithe developed variable density sound record 19 thereon arranged adjacent one row of sprocket holes. While I have described the filmas being o f the motion picture type it need not necessar1- Aas . which is transverse to 'in Fig. 1 and may 4nism in the case of combined sound and picture records. Moreover, where theiilm 4 is to be used only for the recordingof sound it may have an emulsion which while highlyv sensitive to cathode rays is not necessarily sensitive to any great degree -to ordinary light rays. i

The modified form of my invention illustrated by Fig. 4 is constructed for making a sound record of the variable width type. The cathode ray tube 25 in this case is shown somewhat longer than the corresponding tube 3 of Fig. l but vmay be similai` thereto in the construction of the cathode, the anode and the Lenard window. Within the tube 25 and next to the cathode cup 7 is the centrally apertured plate 26 which by the conductor 27, sealed in the tube wall, connects with the cathode heating circuit. Beyond the plate 26 and in alinement with the opening therein is the tube 28 which as shown is supported by the conductor 29 sealed in the tube wall. Between the tube 28 and the anode 10, I provide the spaced plates 30 which are supported opposite each other by the sealed in conductors 31. The cathode heating circuit is similar to that shown in Fig. l. The source l1 of anode potential in this case connects not only with the anode l() but with the tube 28. Plates 30 connect through their supports 31 4and suitable conductors with the output side of the amplifier 2 which as in Fig. 1 amplifies the current impulses received from a pickup device l. Grid leaks 32 are shown between plates 30 and battery 11. Film 33 upon which the variable width record is made is shown supported on the drum 17 as be moved uniformly past the rays in the manner already described. In this form of my invention it will be noted that variations in potential applied tothe plates 30 in accordance with the sound waves actuating the pick-up device cause a variable deflection in the pencll of cathode rays reachvingthe Lenard window which deflection takes direction of the window slit the direction of movement of the film. The pencil of rays preferably is so adjusted relative to the slit that as it is vibrated by the varying potential applied to the plates 30 more or less of the rays find passage through the slit to the film. The developed variable width record thereby made on the film33 is represented atl 34 in Fig. 5. v

In illustrating my invention I have not attempted to show all of the parts thereof in their proper proportions. In the interest of simplicity and clearness I have purposely omitted certain obviously essential features place in the of apparatus of thischaracter, such for eX- modifications may for the film to properly protect it not only from'light but from stray cathode and X-rays which may escape from the tube.

I have chosen the particular embodiments described above as illustrative of'my invention and .it will be apparent that various other e made without departing from the spirit and scope of my invention which modifications I aim to cover by the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for making Aa photographic record of electrical variations on a moving light sensitive member comprising a cathode ray tube constructed to produce a pencil of cathode rays and having an evacuated envelope provided with a window forming a slit through which the cathode rays are e]ect ed from the tube, said tube having electrodes therein arranged to cause a deflection of the pencil of rays in the direction of the slit in accordance with said electrical variations.

2. Apparatus for making a photographic sound record comprising a cathode ray tube having means for producing a pencil of cathode rays and having an evacuated envelope provided with a metal window forming a slit through which the cathode rays are ejected from the tube, means for supporting a light sensitive member for movement transversely of said slit, a plurality of electrostatic plates in said tube arranged at opposite sides of the pencil of rays and separated in a direction parallel to said slit and means for ap plying to said plates a potential difference which varies in accordance with the sound waves to be recorded.

In witness whereof, I have hereunto set my hand this 15th day of April, 1930.

y HAROLD J; MCCREARY.

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