US2212249A - Electronic device - Google Patents

Description

Aug. 20, 1940. I F. sc 2,212,249

ELECTRONIC DEVICE Filed Sept. 10, 1936 INVENTOR FRITZ SCH/2075A? ATTORNEY PahnteiiAug. 20, 1940 2,212,249 ELECTRONIC DEVICE Fritz Schroter,

, a corpora- Application September 10, 1936, Serial No. 100,161

Germany September 12, 1935 9 Claims. (01. 178-75) This invention relates to electronic signaling apparatus and in particular to television receiving Jection of the picture.

P. Selenyi has described in Elecktrotechnishe Zeitschrii't, vol. 56, No. 35, 1935, on page 961 an carrier through electron charges and subsequent contains in the direction of movement of the in- 10 dusting with a powder such as lyco-podium powtermediate film Assuming for instance 200 such der. This author furthermore has already pointed lines, it would be necessary in a line transversal to the applicability of this method to intermediate to the advance of the intermediate film to provide film television reception To this end, the image 200 independent stationary recording systems opmade visible through dusting on a transparent or erating simultaneously, past which the film moves l5 reflecting carrier is recreated on the recelving continuously andin synchronism with the respecscreen at high enlargement by way of diascopic tive photo-electric evaluation at the transmitter, or epidiascopic projection. in order later to be projected on the receiving One 01' the objects of my invention is to pro screen following the dusting 1n step-like fashion vide n mp ved in rm a film type of tele- (Maltese cross) or in continuous running (by 20 11 System of the kind p opo e by Sel nyl. the use of an image balancing arrangement for Another object 01 my invention is to provide instance Wehlers prism wheel, mirror arrangea television a paratus which shall have increased ment according to Mechau). At the transmitter resolution by supplying a substantial increase in therefore, 200 separate photocells or photo-elethe number of elemental areas representative of ments with the same number 01' adjoining am- 5 the picture surface. pllfler channels are required or else in place A further object 01' my invention is to provide thereo a transformation arrangement which disa simplified intermediate fllm projection televitributes the image modulation gained in the S111- sion receiver which shall be easy to operate and gle channel method, true to the image points over have comparatively low initial cost as well as low 200 channels. so maintenance cost. It in view 01 the structural difliculties in the Other and ancillary objects will ppear upon atore-described multiple arrangement the numconsideration of the specification taken in conber of the simultaneously acting transmission j n ti n wi h the raw ng, in which: channels would be made smaller than the number Fi 1 shows one embodiment of my invention; of divisions along the one or the other image co- 35 Fig. 2 shows an electrode structure used in the ordinate, i e smaller than the number of lines embodiment shown in Fig. 1; appertaining to the dimension under considerai 3 h w a ir it scheme: and tion, there arises the necessity of a rapid relative 4 S fiWS fl e odim nt of my invenmovement of the intermediate nlm to the recordtion. ing means In view of the apparent mechanical 4n B l nyih s po nted out that h s dusting method dimeulties of such a method this invention enwould permit the recording of images up to visages the application of moving modulated 10 em n areas D nd- Since the cathode rays for the image productmn whereby order of the number of elemental areas in the these cathode rays produced in the vacuum act im 1 68 od y r y t 50 000 and m re f directly or indirectly in the free space in order o definition the ecording according there to produce on the carrier of the image to Selenyi's method would be exceeded at 124 record the locally varying electron charge, over images per second This drawback is now overwhich the fine particles are dusted. come in accordance with this invention by means Hereby the intensity control of the cathode ray of parallel connection of several transmission through the transmitted image modulationaswell channels in conjunction with storage and amplifi= as the deflection in accordance with one of the two image coordinates takes place in the ordinary way in the cathode ray tube proper.

Figure 1 shows a mode of structure according to the invention relating to a special construction 5 a of the grid-controlled electronic recording: system.

Between the anode plate I and the grid 3 of slotlike construction, there is moved the record carrier which is a transparent, highly insulating film free of emulsion, whereafter it passes through the dusting and projection zone. The film 2 suitably forms an endless loop of sufilcient length in whose circular path in back of the projection zone a device for wiping oil the dusted powder is inserted. In parallel to the grid slot 3, an indirectly heated cathode is arranged consisting of a tubular ceramic body whose bore contains a heating helix 5. This incandescent cathode whose length corresponds to the image line to be traced on the film 2, instead of having a smooth surface has a roughened surface provided thereon such as shown greatly enlarged in Figure 2 as part of the longitudinal section through 4. The cathode may for example consist of alternate rings of metal separated by smaller diameter insulators to give the raised surfaces 9, Hi, II which are covered with a conducting material and separated from each other by insulating intermediate spaces. In this manner the cathode is subdivided into a plurality of electrically independent emission zones corresponding to the line. According to Figure 1 and Figure 3 these emission zones are connected across conducting leads to a corresponding number of contacts 6 arranged in the interior of the cathode ray tube 8. The connections are inserted through and held by the glass wall. They come in contact in succession with the cathode ray i modulated and moving along the line and produced in the tube 8, and these connection lines owing to suitable preparation of their surfaces are charged negatively. The lycopodium powder 43 in the sieve 4! may then be dusted over the insulating medium.

In Figure 3 there is shown the circuit scheme. The cathode 4 shown in enlarged cross section is provided with an oxide layer l2 emitting electrons said layer being disposed on the side facing the grid 3 or slot shaped orifice 3' of the grid and also facing the film 2. The oxide covers the metallic carrier ring surrounding the entire circumference of the cathode and which is in connection with a constant current source at the inner contact 6 of the cathode ray tube 8 as well as across the resistor [4. Element l3 designates an anode with slot-shaped orifice provided in the cathode ray tube, and in back of which the line of the contacts 6 is arranged. The potential of the current source connected with l2 across it is slightly more positive than that at which grid 3 is maintained constant. Consequently, in the absence of the cathode ray, the grid 3 produces a blocking effect across the entire length of the cathode 4, so that no electrons can arrive at the film 2. If however, the modulated cathode ray 1 moved along the line of the contacts 6 supplies the cathode elements with less negative charge. The field of the anode l grips in a corresponding degree through upon the charged emission zones of the cathode 4 and from there is caused a transit of electrons to the carrier of the record 2, which transit is controlled in accordance with quantity of charge. The emission of each cathode element into a region of negative potential relative to the grid by proper choice of the radiation conditions, of the size of the resistor l4 and of the capacity of the charged part, continues up to the time at which the cathode ray returns to the same place, i. e., it last approximately throughout the du ation of an image line.

Since during this time the film 2 has advanced by the width of an image line, there will be obtained on the carrier 2 a suflicient spacial electron charge, so that it is possible to produce charges on the film even in case of a very large number of image points. The recording frequency becomes equal to the image line frequency, and hence is essentially reduced as compared with the image point frequency. It is also possible to modify this method; thus instead of subdividing the cathode 4 in Figure 1, to subdivide the grid 3 and to connect its elements with the contact line 6 in the ray tube. In this case a positive or negative image record would be obtained in accordance as to whether the ray 1 at the electrodes 6 has a factor of the secondary emission that is greater or smaller than 2. However, in this case it would be difilcult to eliminate the errors caused by the control of the contact potential at the individual elements of the grid and by the varying activation thereof.

Figure 4 shows another embodiment of the invention. Element i again signifies an anode arranged in back of the film 2 as seen from the side of the cathode ray, and which is maintained at a still higher positive potential than the last acceleration anode in the cathode ray tube proper. The tube 8 is designed as Lenard tube, thus containing a window 4 for the exit of the cathode ray, and consisting of a thin foil of light metal. If beryllium is chosen for said foil the passage of the electron ray into the open can already be achieved with an acceleration potential of about 20,000 volts. If the film 2 is placed closely in front of the Lenard window 4, and if the field between 4 and I still produces a highly accelerating action upon the electrons passing into the open, there can be obtained on 2 a very high electron charge fluctuating along the image line with the variation in the brightness. The carrier of the foil 6 is a metal piece 3 fused to the glass tube 8 in accordance with a known method, and which has a hollow space for circulating cooling water. 7

Element l5 designates an inner conducting layer serving at the same time as acceleration anode, l6 and H are crossed coil pairs for the magnetic deflection of the cathode ray in the direction of the image and line, It is the first anode, I9 is the control electrode for the intensity modulation, 20 is the shielded cathode system, and element 2| is the lead-in of the electrode connections. In order to increase the life of the Lenards foil under the action of the outer air pressure, it is preferred to mount the same on a plate having a small longitudinal slot. In this case the operation would be carried out only with a single line movement of the cathode ray along this slot, while the line alternation of the recording is effected by continuous advance of the film 2. In this case, it is obvious that one of the deflection coil pairs l6, I! can be dispensed with, while the image alternation is synchronized with the advance movement of the film.

Having now described my invention, what I claim is:

1. The steps in the method of producing charges on an insulating medium in air comprising developing a. plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a focused beams of electrons, and controlling the intensity of the directed electrons in accordance with the produced beam.

2. The steps in the method of producing charges on an insulating medium in air comprising developing a plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a focused beam of electrons, controlling the intensity of the produced beam and controlling the intensity of the directed electrons in accordance with the produced controlled beam.

3. The steps in the method of producing charges on an insulating medium in air comprising developing a plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a. focused beam of electrons, controlling the intensity of the produced beam, deflecting the controlled beam, and controlling the intensity of the directed electrons in accordance with the deflected controlled beam.

4. The steps in the method of producing charges on an insulating medium in air comprising developing a plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a focused beam of electrons, controlling the intensity of the produced beam, sequentially actuating each of the plurality of developed sources by the controlled beam, and controlling the intensity of the directed electrons in accordance with the actuation of the developed sources by the produced beam.

5. The method of producing charges on an insulating medium in air representative of the intensity of illumination of elemental areas of an image to be produced comprising the steps of developing a plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a focused beam 0! electrons, developing a source of electrical impulses representative of the image to be produced, controlling the intensity of the produced beam in accordance with the developed electrical impulses, and controlling the intensity of the directed electrons in accordance with intensity of the controlled produced beam.

6. The method of producing a record on an insulating medium in air representative of an electrically transmitted image which comprises it the steps of developing a plurality of elemental thermionic electron emitting sources, directing the electrons emitted from the sources through air toward the insulating medium, producing a focused beam of electrons, developing a source of electrical impulses representative of the image to be produced, controlling the intensity of the produced beam in accordance with the developed electrical impulses, controlling the intensity of the directed electrons in accordance with intensity of the controlled produced beam, and subsequently dusting dielectric particles over the insulating medium.

'7. In 'combination, an insulating medium, a flat electrode, an apertured electrode, means for positioning the insulating medium between the two said electrodes, a plurality of elemental thermionic electron emitting sources positioned adjacent the apertured electrode, a cathode ray tube comprising means for developing and controlling a cathode ray, and means to control the intensity of emission of electrons from the elec tron sources by the intensity of the cathode ray.

8. In combination, an insulating medium, a fiat electrode, an apertured electrode means for positioning the insulating medium between the two said electrodes, a plurality of elemental thermionic electron emitting sources positioned adjacent the apertured electrode, a cathode ray tube positioned in register with said sources comprising means for producing and controlling a concentrated cathode ray, means to control the intensity of emission of electrons from the electron sources by the intensity of the cathode ray, and means to direct the emitted electrons through air upon the insulating medium.

9. In combination, an insulating medium, a flat electrode, an apertured electrode, means for positioning the insulating medium between the two said electrodes, a plurality of elemental thermionic electron emitting sources positioned adjacent the apertured electrode, a cathode ray tube positioned in register with said sources comprising means for producing and controlling a concentrated cathode ray, a source of electrical signalling energy, means to control the cathode ray intensity in accordance with the electrical signals, and means to direct the electrons emitted from the sources through air upon the insulating medium.

FRITZ SCIEOI'ER.

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