US2108132A - Television device - Google Patents

Description

Feb. 15, 1938. A. LORA TELEVISION DEVICE Filed Sept. 5, 1933 9 TRANSMITTER i GEN 2 Lul s A. I. BRA

INVENIOR Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE TELEVISION DEVICE Luis A. Lora, Brooklyn, N. Y., assignor to Radio Patents Corporation, New York, N. Y., a corporation of New York Application September 5, 1933, Serial No. 688,087

1 Claim. (01. 250-275) The present invention relates to the electrosecondary electron emission by the pins which optical transmission and reception of pictures would be contrary in direction and opposing electhrough cathode ray tubes. trical charges and therefore will interfere with The purpose of this invention is to prevent the proper scanning action.

5 image distortion and to obtain greater luminous The foregoing and other desirable objects are intensities. attained in this invention by the new principle The basic feature of this invention consists of disclosed and by the novel feature of construca method of electronic scanning whereby an tion, combination and relation of parts, herein image may be dissected into elemental areas described and broadly covered in the claim.

formed by independent conducting elements. The drawing accompanying and forming part 10 A.feature of the transmitter is a nonconductof this specification wherein Figure 1 is a diaing partition imbedded with conducting elements, gram for a transmitting system and Figure 2 said partition dividing the cathode ray tube represents a receiving system is illustrative in intotwo sections, an electron chamber, where character and it is understood that the parts or scanning occurs and a gas chamber where the their relations may be changed in various ways, 15

photoelectric charges are collected. all within the true intent and scope of this inven- Another feature of the transmitter provides tlon. screening means in the electron chamber to focus The well known fluorescent cathode ray tubes the sweeping beam of electrons for each eleused up to date for television purposes, usually mental area, after the beam has been deflected. do not produce sufficient light for enlarged pro- Another feature of the transmitter provides jection. The sweeping beam of electrons in these screening means in the gas chamber to collect tubes must be focussed to a. very fine point to prethe photoelectric charges individually and sucvent the distortion of each pictorial element. cessively in a. manner preventing image disto-r- This is rather difficult to accomplish in a satisfaction. tory manner as the cross sectional area of the A feature of the receiving tube provides means beam varies as it is modulated and also when it toreproduce visibly each elemental area into an is deflected. independent luminous gas discharge of substan- In this invention the beam of electrons is not tial intensity. modulated and its cross sectional area is kept 0 A feature in the electron chamber of the reconstant, thus distortion efiects due to spreadceiving tube prevents image distortion by focusing ing of electrons or variations in sizes of elements the sweeping beam of electrons upon each conare prevented. ducting element after deflection of said beam. The individual isolation of each conducting Another feature in the gas chamber of the element furthermore prevents the overlapping receiving tube, provides screening means. to distortion effects of adjacent elements. 35 modulate the various luminous intensities and The fact that the sweeping beam of electrons to confine each discharge to its respective discarries current from theheated cathode in thecharging element. electron chamber to the screen anode in the gas An advantage of the receiving tube is the prochamber, enables these devices to commutate duction of individual and successive concenconcentrated, high negative potential charges 40 trated luminous discharges of conducting eleupon the surface of the conducting elements and ments of predetermined symmetrical sizes, the thereby cause greater voltage variations of the aggregation of these elements forming a. lumitransmitting tube, and intense concentrated lunous image, the intensity of which-is suitable minous discharges at the receiving tube.

5 for optical magnification and reproduction on a Fig. 1 in the drawing is a schematic illustration 5 large scale. of the transmitting system where l) is an illu- An important feature present in the transmitminated surface, (2) is an optical lens system ting tube and in the receiving tube, is the symprojecting the image light rays reflected from metrical shaping of the electronic discharge for the subject upon a plurality of conducting eleeach elemental area as it is collected by one or ments or pins (4) coated with photoelectric sub- 5 several conducting elements, in order to transmit stances and imbedded in a non-conducting parand receive images of a few wide lines or a large tition (3) which divides a cathode ray tube (23) number of very fine lines. into a light sensitive chamber (5) and a cathode Another advantage of the transmitting tube ray scanning chamber (8). The image is proand of the receiving tube is the prevention of jected upon the photoelectric surfaces of pins 55 (4). These pins emit electrons in proportion to the amount of light they receive. One pin or a group of pins may be connected at a time by the scanning beam of electrons sweeping over their conducting surfaces (4A) exposed in the scanning chamber.

When the beam of electrons impinges upon the end of a pin or a. group of pins, at (4) for ex ample, the negative charge thus imparted to these pins establishes a diiference of potential between their surfaces in the photo electric chamber (5) and the anode screen (6) facing them. Thus an electric current is enabled to flow from source ([1) through a coupling load resistance (l5) then from screen (6) at point (41;) for example, and the pin or group of pins at point (4s) being in contact with the seaming beam of electrons. The electrical circuit is then completed through the beam of electrons (9) the cathode (I!) which emits them and the negative side of potential source The various amounts of electrons emitted by the photo electric surfaces of pins (4) in chamber (5) causes increases or decreases of the current transferred through the scanning beam of electrons and thereby causing voltage drops in coupling resistor (l5), said variations being transferred electrostatically through condenser (i9) connected to a thermionic vacuum tube amplifier (20) which has its control grid biased by a. battery (l8) and a current limiting resistor (IS). The voltage variations amplified are transferred to the transmitter proper which radiates the image's signal.

Defiecting plates (l0), perforated accelerating anode (H) and the negative cylinder (l2) are of standard design as are now well known in the art.

The receiving system as illustrated in Figure 2 consists of an electronic discharge device system similar in construction to the cathode ray tube previously described in the specifications except that gas chamber contains in this case a luminous producing gas and that the ends of the pins exposed in this chamber have not photoelectric properties. The image signal received is magnified by a selective amplifying receiving system (60). The last stage of amplification comprising a power tube is shown at (50). The signal voltage variations delivered by the output circuit of this tube are transferred electrostatically through condenser (49) modulating the voltage of anode screen (36) Both cathode ray tubes operating in exact synchronism, the group of pins commutated by the scanning beam of electrons at any particular moment will acquire. a negative charge. This causes an electric current to flow from the anode screen (36) to the pins (34) and the commutating beam of electrons. Due to the fact that chamber (35) contains luminous ionizable gases or vapors, a. luminous glow discharge takes place between the pins commutated and the screen anode.

Screen (31) in the scanning chamber is charged with a small negative potential which serves the purpose of further reducing the cross sectional area of the scanning beam of electrons. This feature of my invention is also used to reduce secondary emission effects from the ends of the pins in the scanning chamber which otherwise would interfere with the proper sequence and distribution of electrons from the scanning beam and the various pins. Screen (31) serves also the purpose of varying the size of each elemental pictorial area and thereby may be used to control the sharpness of definition of the image. Each luminous discharge corresponding to the pictorial element, equals approximately in area the cross section of the electron beam near the surface of pins (34) in the scanning chamber and is very small, however, the glow discharge may, under favorable conditions, be very intense as it is the result of a. highly concentrated electrical discharge in the particular area.

I claim:

A cathode ray device for receiving signal energy for transformation into picture images comprising a first evacuated chamber, a second chamber containing a light-producing gas, an insulating partition separating said chambers and having a plurality of conductive elements embedded therein forming a scanning mosaic, each of said elements forming a conducting path connecting said chambers, means for producing an electron beam in said first chamber for scanning said mosaic, a metallic grid in said first chamber disposed opposite said mosaic and electrically charged to focus the electron beam upon the several elemental areas of said mosaic, and agridlike anode in said second chamber disposed close to and opposite said partition.

LUIS A. LORA.

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