US2669671A - Four-color kinescope - Google Patents

Description

Feb. 16, 1954 LQ B. HEADRICK FOUR-COLOR KINESCOPE Filed Oct. 6. 1951 QOIQQOIQ m34@ mo Eig INVENTOR. [ewls Bladzld ATTORNEY A Patented Feb. 16, 1954 FOUR-COLOR KINESCOPE Lewis B. Headrick, Lancaster, Pa., assigner to Radio Corporation of America, a corporation of Delaware Application October 6, 1951, Serial No'. 250,139

This invention relates to cathode-ray tubes and particularly to improvements in multi-'color kinescopes of the kind containing a target assembly made up of a plurality of ray-sensitive screen elements, one of which serves to produce a black-and-white representation of the detail of a multi-color image and the other to produce the various primary and natural color-components of said image.

It is appreciated by those skilled in the art to which this invention appertains that in order to transmit a color-image with a high degree of fidelity, the color-video signals must contain a large number of relatively high frequency components. In order to accommodate video signals of such a character in a band-width of approximately 4 mc. the principle of mixed high frequencies has been used. One such system is described in the copending application of Alda V. Bedford, Serial No. 117,368, filed September 23, 1949. In said system the relatively high frequencies of the transmitted video signals represent the high deiinition or detail of the televised image and the relatively low frequency upon a black-and-white screen and the beam from the other gun generates the colors by impinging upon another screen made up of colorphosphor elements. When the images on the two screens are viewed simultaneously the vobserver sees a composite image, in its natural colors, of the scene or object being televised.

One very real advantage of the Rose receiving system is that its reproducing apparatus does not require the neness of structural detail that is required in color-image reproducing systems wherein the mixed high video signal is not divided into its separate components at the receiver.

In one embodiment of the Rose invention the detail or black-and-whte image is produced on the screen of a conventional kinescope and the colors are produced in a second kinescope having a red, blue and green phosphor screen. The separate images are optically combined with the aid of a mirror. In another embodiment,

5 Claims. (Cl. 313-70) 2 Rose employs a single tube containing a. twosided viewing screen. Here the picture detail" is drawn in black-and-white on the obverse face of the screen by the pencil of rays from the highfrequency gun and the color-information is generated on the rear face of said screen by the ifnpact thereon of the rays from the low frequency gun or guns.

Irrespective of the advantages of the Rose receiving system it may be said generally that its color-image reproducing apparatus does not lend itself readily to installation in television sets designed for use in the home. This is so because neither a double-ended kinescope' nor a plural tube and mirror assembly can be accommodated in a cabinet of conventional design.

Accordingly, an object of the present invention is to provide an improved color-image reproducing apparatus which shall possess all of the advantages of the above described Rose apparatus, and one further characterized by its unitary and relatively compact structure, Whereby said apparatus may be housed in a television cabinet of standard form and dimensions.

Another and important object of the present invention is to provide an improved 4-color target-assembly for color-kinescopes, and one free from parallax and color-alignment problems.

The foregoing and other objects are achieved in accordance with the invention by the provision of a color-kinescope having a target assembly comprising a transparent viewing-screen which is coated all over its rear or target surface .with a black-and-White phosphor (e. g. P4) and is provided adjacent to the same side with a multiplicity of target elements having a plurality of surfaces made up of color-phosphors that .exhibit respectively dilerent color-response characteristics when struck by electrons. Here the colors are imposed directly upon the black-and- White high detail image, instead of indirectly in accordance with the principle of the invention;

Fig. 2 is a transverse sectional view of the gunassembly of the kinescope of Fig. 1;

Fig. 3 is a fragmentary view in perspective of the color target assembly of the kinescope of Fig. 1; and

Fig. 4' is aview in perspective, from thegunside ofthe screen assembly, showing a portion of the White-phosphor target and a single cell of the color-phosphor target; the drawing being marked to show the different plathsoi. approach of the several beams to said target parts.

In the drawing. whereinline reference characters represent the saine or corresponding parts in all figures, I designates an evacuated envelope having a bulbous portion or. main chamber 3 which terminates at one end in a transparent face plate or window 5 and, at its oppositeend, in a rearwardly extending axial neck portion l'.

.The inner face of. thevwindow va-serves as the Lfqundation.surfacecf thefour-color Vscreen or iitarget of the invention. Alternatively-a sepa- `rate `foundaticn plate, notshown, `may-be used.

either event,'.the-targ et assembly comprises ,.a.1 translucent. white-phosphor coating 9 Yonthe inner face of the foundation plate.and a metal honeycomb structure, indicated generally at l i,

v suitably supported on oradjacent ,to the whitephosphor coating 9.

The, honeycomb portion Il of, the target-as- `scmbly comprises ,a b ank of hollow metal cells VI la, Hb, etc.. arranged in contiguous. rows. The

cells are. hexagonal in cross-section and two adj,acent ones of the six inner faces'of each cell are allotted tothe production of each cf the thlee fprimary.col ors. Thus, as shown in Fig. ji, the inner faces vwhich are designated r, 1" are coated with,aphosphorrmaterial that emits red `light when struck byelectrons, and the 4other pairs of inner faces b- -b, g-,g. 4are provided 'with suitable blue and ,greenphosphor coatings, respectively.

The source of electronsV for lac :tivating the white phosphcrporticn 9of the target assemblyV comprises an electron-gun Sw mountedon the long central axis of the envelope within the neck l. Three other guns`9r, Sb and'iilgare mounted A-,flashion (ige. 120 apart) about' the white gun 9w and serve, respectively, toactivate the phosphor deposits on the inner faces of the celluflair portion Il of the target-assembly-S--l I.

-A magnetic deflection coilM on the-neck Tof the tube serves-to impart the requisite scanning movement tc allfour of the electron beams. .A "beam-convergence coil M', closer to the bat- 'tery of guns, maybe Vused'toensure thatalI-f'our beams maintain their correct relative `positions throughvout the-scanning raster.

`From the foregoingdescription it will be ap- '.parent f that. thel present invention Vprovidesan #improved color-kinescope of a kindLcapable, of

4 utilizing both the high and low frequency components of so-called mixed-high signals, and one characterized by its unitary and relatively compact structure.

What is claimed is: 1. A target-assembly for a color-kinescope, said assembly comprising: a foundation plate havingl a. target surface consisting essentially of -a Lphosphor material thatfexhibits a substantially White color-response characteristic when struck .:by electrons, in combination with a multiplicity Number of, target elements extending in a direction substantially normal to said white phosphor surface. each of said target: elements having a plurality of4 faces consisting essentially of respectively different,phosphormaterials that exhibit diiferent color-response characteristics when struck by electrons.l

- `2. A target assembly in accordance with claim 1 and wherein each of said target elements has A.at least` three phosphor faces eachindividual to onevof the primary-color phosphor materials.

3. A target assembly in accordance with claim land, wherein said. target elements comprisea .envelope containing a viewing screen having an electron-sensitive target surface consistingV essentially of a phosphor material that exhibits a substantially white color response charactcrj istic when struck by electrons, a beam-source of electrons mounted in a position to scan said phosphor-surface and thus to produce a black and-white image thereon, a second electronsensitive target surface mounted adjacent to said first mentioned surface and extending in a direction substantially normal thereto, said second i surface consisting essentially of a phosphor material that Vexhibits a primary-color responsecharacteristic `when struck by electrons, and a second beam source of' electrons mountedf'or `bombarding said second electron-sensitive sur- -face and thus to endow said black-and white `image with a primary-color component.

' LEWIS' B. HEADRICK.

References Cited in the le` of this'patent STATES PATENTS Name .Date 2,296,908A Crosby Sept. 29, 1942 2,532,511 Okolicsanyi ,Dec. 5'1950 2,579,665

Green Dec. 25, 1'951

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