US2389645A - Television system - Google Patents

Description

NOV. 27, 1945. E, SLEEPER, JR 2,389,645

TELEVISION SYSTEM Filed Feb. 5, 1943 2 Sheets-Sheet 1 INVENTORY GEORGE E. SLEEPER JR.

QZEW.

A T TORNEK Nov. 27, 1945. e. E. SLEEPER, JR

TELEVISION SYSTEM Filed Feb. 5, 1945 2 Sheets-Sheet 2 GEORGE E. SLEP 'R JR.

ATTORNEK Patented Nov. 27, 1945 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to television systems, and in particular to a system for transmitting pictures in color.

An object of my invention is to provide a television system which will eliminate the principal disadvantages inherent in present systems.

One such system employs rotating color filter discs in the transmitter and receiver. This involves mechanical difilculties and the problem of synchronization. In my system no mechanically moving parts are used. Systems which require projecting images of successively difierent colors on the photo-sensitive screen of the pick-up tube do not produce true color pictures because the discharge lag, especially in the storage-type tube, causes a carry-over of one color image to the next, with an undesirable mixing of colors. This objection is overcome in my system by allotting separate areas of the screen to each color, so that each area is always receiving images of the same color. Another system employs a separate tube for each color which has the disadvantages of increased cost and the diificulty of p acing the tubes close enough together. My system empl ys a single tube for pickup and a single tube for picture production.

Another object of my invention is to make it possible to employ a, standard black and white television system for transmitting color pictures by the addition of simple parts which effect the conversion. I accomplish this by introducing into the optical system which projects the images onto the screen of the pickup tube, a suitable means for simultaneously producing a plurality of images of the object, filtering each of these images for a different color, and projecting each color image on a separate area of the screen. These images are then scanned in a group as one picture in the same manner as a single black and white picture.

The tube in the receiver reproduces in black and white separate images corresponding to the color images in the pick-up tube. These images lack only color; they have the correct detail and intensity. The color is restored to each image by collecting it through a color filter and then by a suitable optical means the color images are superimposed on the viewing screen to produce a picture of the original object in its natural color.

It will be noted that a conversion of a standard television system to color is accomplished simply by adding an optical means at the transmitter which will project a plurality of images of difierent color into the tube and by adding a similar optical means at the receiver which reverses the process and assembles the picture. However, although this conversion can be simply effected, it will be apparent that in making the combination, a complete system of color television is created which has the advantages pointed out above.

I will now disclose, by reference to the accompanying drawings, an apparatus in which my invention is embodied.

Fig. 1 shows schematically the transmitting portion of the system.

Fig. 2 shows the receiving portion.

Fig. 3 shows diagrammatically in perspective, one means for producing a plurality of images of different color of the object.

Fig. 4 shows another means for this purpose.

The number of color images obtainable by my system is a matter of choice For purposes of illustration, I have disclosed four. I shall therefore refer to the lens system which produces the four images as a quadchromatic lens.

Referring to Fig. 1, the object I0 is picked up by the quadchromatic lens i I, which projects four images l2, l3, l4, [5 of different color onto the photoelectric screen iii of the pick-up tube IT. The images l2, l3, I4, I 5 maybe red, yellow, blue, and green, respectively. The four images are conveniently grouped in a quadrangle. An important feature of my system is that the images do not overlap. The area of the screen It upon which any particular color image is projected continuously receives and responds to images of that same color.

The pick-up tube and transmission equipment may be of the conventional construction employed for black-and-white television and comprises the cathode ray tube I l operated in the usual manner for developing picture signals and provided with a photo-sensitive mosaic screen it. Theelectron beam 20 is projected onto the screen It and is caused to scan the screen in the usual manner by means of deflection coil 2!, 22, connected to line andframe deflection generators 23, 24, respectively. The responses from the photosensitive screen are conveyed to the amplifier andradio transmitter 25.

, The radio receiver 26 (Fig. 2) is connected to the line andframe deflection generators 21, 2B which are connected to thedeflection coils 29, 30, respectively, which deflect the electron beam 3| of thecathode ray tube 32 in the usual manner. The picture signals supplied to the tube produce fourpictures 33, 34, 35, 36, corresponding to the four images l2, l3, l4, [5. These pictures are intensities of the originals.

A quadchromatic lens 31 which may be similar to the lens II, but reversed, collects the tour pictures, supplies the appropriate color to each by a filter, superimposes the four color images and projects a picture in natural color of the object I. on theviewing screen 35.

The quadchromatic lenses referred to above could be constructed in different ways. For example, iour separate lens systems could be employed, each provided with a filter. Each 01' these lens systems would project an image of the object in a diflerent color on the screen of the pick-up tube. This means is thought to be readily understood without illustration.

An alternative means is shown in Fig. 3 where the object in is picked up by a lens 40, behind which are located fourprisms 4i, 42, 43, 44, adjusted relative to the lens 40 and to each other so as to produce four images of the object. Associated with the prisms arecolor filters 45, 46, 41, 48. A second lens 49 projects the four color images i2, i3, l4, "5 on the screen it.

In the modification of Fig. 4, mirrors are substituted for the prisms. Four images of the object III are reflected by themirrors 50, 5|, 52, 53, ontomirrors 54, 55, 56, 51, which reflect the separate images through thecolor filters 45, 48, 41, 48, to the lens 49.

As previously explained, the quadchromatic lenses II and 31 (Figs. 1 and 2) are substantially identical but are used oppositely.

Having described my invention and the manner in which it is to be employed, what I desire to secure by Letters Patent is:

1. In combination with an electronic scanning device having a photoelectric screen and a single electron beam for scanning said screen, an optical system interposed between said device and the object, said optical system including means for producing a plurality of images of the object, color filters associated with said means, one filter for each image, and means to project the color images on said screen, each oi. said color images being located on a separate area of said screen.

assasss 2. A television system for transmitting pictures of an object in color comprising a Pick-up tube having a photoelectric screen and a single electron beam for electronically scanning said screen, means for projecting a plurality of separate color images of the object on said screen. means for transmitting the picture .signals, a receiver for said signals, a projection icture tube operated by said receiver to produce a plurality of separate colorless pictures or said color images, means ior imparting the appropriate color to an image 01 each of said pictures, means for superimposing the colored images and projecting upon a viewing screen a picture of the original object in color.

3. A television system for transmitting pictures of an object comprising a pick-up tube having a screen, means for projecting a plurality'of separate color images or the object on said screen, means including electron deflecting means for electronically scanning said screen, means for transmitting the picture signals derived from said scanning, a receiver for said signals, and means including a cathode ray tube having a single electron beam and a photoelectric screen for producing a picture of the original object composed of the images of said object produced on said photoelectric screen.

4. A television system for transmitting pictures of an object in color comprising a cathode ray pick-up tube having a photoelectric screen and means for electronically scanning said screen, means for projecting a plurality of separate color images of the object on said screen, means for transmitting the picture signals, a receiver for said signals, a cathode ray projection picture tube having a single electron beam operated by said receiver to produce a plurality of separate colorless pictures oi said color images, means for irnparting the appropriate color to an image of each of said pictures, means for superimposing the colored images and projecting upon a viewing screen a picture of the original object in color.

GEORGE E. SLEEPER, JR.

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