SU66196A1 - Cathode TV Transmitter - Google Patents

Description

Cathode television transmitters in which electron image transfer from a photocathode is used are known.

The disadvantage of such television transmitters is their low sensitivity. In the described television transmitter this disadvantage is eliminated by the fact that in it the optical image to be transmitted is transformed by a continuous photocathode into an electronic image that is focused by an electron-optical lens on a screen-crystal, made for example of alkaline halide. In the latter, at each point, under the action of electron bombardment, colored centers (opaque particles) appear in an amount proportional to the intensity of the electron beam. Thus, in a crystal of opaque particles, a "latent image of the transmitted object is formed. By flashing such a crystal with an extraneous light source, you can project the resulting image onto a photocathode, where the image is decomposed into elements and a video signal is formed.

FIG. 1-4 depict various embodiments of the cathode tubes and the cathode television transmitter optics.

FIG. Figure 1 is a schematic diagram of a transmitter tube with double accumulation of radiant energy and double transformation of an optical image into an electronic one.

The image of the transmitted object / lens 2 is designed by a photocathode 3, which turns it into an electronic image. The latter is focused by the electron lens 4 and is transferred to the intermediate crystal 5, creating in it a latent image of the transmitted object of opaque particles. The crystal 5 is illuminated by a stream of light from an external source 6, in front of which a lens 7 is installed, as a result of which the latent image is projected onto the photocathode 8 and is again converted into an electronic image. The latter is focused by the lens 9 and is transferred to the signal electrode IU, where the image is decomposed into elements and a video signal is generated. For the decomposition of elements in the process //

No. 66196

electron gun and electron beam scanning system 12. All elements of the tube are enclosed in a common glass cylinder / 5. The useful signal is removed from the active resistor 14 connected to the rear metallized surface of the electrode 10. The voltage source 15 serves to create an electric field used to transfer the electronic image of the photocathode 3 to the crystal 5.

The accumulation of radiant energy in this system during the transmission of one frame occurs twice: during the deposition of opaque particles in the intermediate crystal and the accumulation of electrical charges on the signal electrode.

In order to transmit moving images, it is necessary to change frames in a crystal, which is achieved by crystal discoloration by removing opaque particles onto a positive electrode applied to the crystal by a field created by source 16.

The electric field created by the power source 17 serves to transfer images from the photocathode 8 to the signal electrode 10. The power sources 18-19 serve to power the scanning system.

In order to show through the intermediate crystal, it may be necessary to insert a mirror inside the tube, which will throw light off the crystal. If the crystal needs to be illuminated by parallel rays, the tube can be changed. One such structure is shown in FIG. 2. The light flux from source 6, passing through lens 7, falls on crystal 5 in the form of a beam of parallel rays. Due to the use of the bent tube 13, additional accelerating electrodes, not shown in the drawing, and magnetic coils 20 fed from the source 21 are inserted into it to rotate the electronic image transferred from the photocathode 3 to the chip 5. The rest of the tube design does not change. The interruption of the electron image feed to crystal 5, instead of changing the voltage from source 15 (Fig. 1), can be accomplished by changing the current from the source 21 creating the magnetic field by the same law.

Pa figs. Figure 3 shows the design of a tube with double accumulation of radiant energy by forming a latent image in the intermediate crystal 5 with accumulation of electrical charges on the signal electrode 10 and the ordinary transformation of the optical image into an electronic one (photocathode 3. The operation of this tube differs from the operation of the tube shown in FIG. 1, in that the optical image from the crystal 5 is not projected onto an intermediate solid photocathode, but directly onto the signal electrode 10. The latter, in this case, represents is a discrete cathode (mosaic) on a thin dielectric plate or semiconductor.

The storage systems described can be transformed into a supersystem having a transverse conductivity signal electrode mosaic and electron beam sweep from the side, inverse projection of the image, or a system with secondary electron video signal amplification by diverting the secondary electrodes from the mosaic from the sweep beam to the multiplier.

In an intermediate crystal transmitter, any other image scan can be used. FIG. 4 is a schematic diagram of a tube in which an ordinary accumulation of radiant energy takes place (in the form of a latent image. In intermediate crystal 5) and an ordinary transformation of an optical image into an electronic one (photocathode 3. A latent image in crystal 5, received from the transmitted object /