US2544690A - Color television - Google Patents

Description

March 13, 1951 I 5. J. KOCH E/TAL COLOR TELEVISION 2 Sheets Sheet 1 Filed Dec. 26, 1946 FIG. 2

March 13, 1951 s. J. KOCH ETAL 5 5 COLOR TELEVISION 4 Filed Dec. 26, 1946 I 2 Sheets-Sheet 2 FIG.3 3

OQQOQOOOO000.000.06.606.

PIC-L4 3 DOOOQQQQQOOQ QOOQQOQQQOQOQQQOOQ4 Patented Mar. 13 1951 UNITED STATES PATENT OFFICE COLOR TELEVISION Stanley J. Koch, Clifton, and Robert E. Ruther-' ford, Nutley, N. J.,' assignors to Allen B. Du Mont Laboratories, Inc., Passaic, N. J., a corporation of Delaware Application December 26, 1946, Serial No. 718,364

This, invention relates to color television. It relates particularly to color television in which provision is made for transmitting the three colors red, blue and green simultaneously.

6 Claims. (Cl. 250164) In carrying out the invention provision is made fluorescence, when scanned with the beam of a for applying color response material on surfaces cathode-ray tube, one giving red fluorescence, and that are at angles to each other. Cathode-rays one giving blue fluorescence, for example. The are provided to scan the respective color resize of these faces are such that a single group is sponse materials. Three sets of surfaces are proequal to or smaller than the scanning spot as norvided with the surfaces of each set parallel to the mally used to provide a predetermined size teleother surfaces of that set and substantially pervision picture. pendicular to the surfaces of the other sets. Each gun 4 is a source of light, that is, one gun The invention may be understood from the excites the red fluorescent material on faces 5, description in connection with the accompanying another gun excites the green fluorescent madrawings in which: 7 l5 terial on faces 6, and the third gun excites the Fig. l is a side view of an illustrative embodiblue fluorescent material on faces 1. Thus by ment of the invention, showing a cathode-ray applying color television signals simultaneously tube. from a color television transmitter source in the Fig. 2 is a rear view of the cathode-ray tube known way to the respective guns the three shown in Fig. 1. colors are combined or merged in the faces 5, 6

Fig. 3 is a plan view of enlarged elements showand l of the screen 3 to produce colored pictures. ing a screen for said tube. This arrangement can, by keying in the known Fig. 4 is an edge view of Fig. 3. way, also be used with sequential colored tele- Fig. 5 is a plan view on an enlarged scale showvision systems by applying the proper color seing a small portion of Fig. 3. quence to the grids of the respective cathode-ray Fig. 6 is a cross section on a larger scale along tube guns 4. the line aa of Fig. 5 showing the aluminum It will be understood from this description that backing of the fluorescent screen. the angle at which the electrons strike the 7 s an edge view of a modification of fluorescent surfaces 5, 6 and 1, is critical. The Fig. 4. 3O electrons from guns 4 should strike their respec- In he drawin s referenc ch ra er 1 indi a s tive surfaces in a direction that is perpendicular a glass nvelop r u upon the i i f c 2 of or substantially perpendicular to these surfaces which is located a screen 3 to be described more i der t btain the best results. in detail below. This screen 3 may be placed It has been found to be advantageous to apply upon the inside face 2 of the tube I or the screen a Very thin layer 9 (Fig. 6) of evaporated aluy be embodied in the inside Surface of the minum to the fluorescent surfaces 5, 6 and l. face 2. When such a thin aluminum layer 9 is applied Three cat odey u s 4 are arranged at to the surfaces 5, 6 and I the electrons that strike angles to the c 2. e Screen is provided W perpendicularly to the aluminum surfaces will three sets of parallel faces and each cathode-ray 40 penetrate th m i it readfly a d thu un 4 is so located that its beam strikes only on excite the fluorescent material on these surfaces, s t f th parall l fac of the s These but the electrons that strike at an acute angle to c y guns 4 are located in positions to the surfaces will not penetrate to the fluorescent p j c their Cathode-rays perpendicularly material due to the greater length of aluminum su s antial y p p d u ly n the three path through which they traverse at acute angles. spective surfaces of the screen which the beams h 1 t from any one of th guns 111 of these guns scan. 7 penetrate the faces which are perpendicular to A glass pl 3 is shown in Fi 3 to 6 havin the electron beam of such a gun, but the eleca pattern of depressions and projections protrons from the same beam which strike the other duced by embossing as shown in Fig. 5 on an enfaces will strike them at a very acute angle, and larged scale. Each one of these projections has because of the presence of the aluminum layers three faces 5, G and I to which screen material they will not excite the unwanted colored fluohaving different color response characteristics rescent materials under these layers. When such is applied. Each one of the faces 5, 6 and l, is at layers are used the guns can be brought closer approximately 90 to each of the other two faces. together and in this way the need for correction for the registry of the patterns due to the various angles of the guns is decreased. A further advantage of the aluminizing using the reflection phenomena of the aluminum surface allows the tube to be viewed from a greater angle than otherwise would be the case, that is, the group of facets 'beinggmirrored by the aluminum reflects the lightjfromzthe opposite facets. .For example, surfaces which produce green light will also :be reflected from the other surfaces 6 and I so that the viewer from the far side who would not otherwise see the equal area of the green facet sees by reflection the desired amount :of the green color. This applies-to all three colorsso that there is not only a larger viewing angle for registering the proper colors, but there is also a better mixing of the colors .by reflection of the various lights within the facets themselves.

This larger viewing angle can be improvedby providing lenses 8 (Fig.2?) on the front side ofthe screenshownin Fig. 3,-each lens being the size of a group of three colors represented ,by reference characters 5,-6.and I. This improvement in the viewing angle comesabout by .virtue of the .ability of the lenses to assist in the concentrationiof the three beams of light from the three sets of facets 5, 6, and 1 into one .beamof light maintaining "a goodcolor balance over a wider ,angle than is, possible without the lenses.

-What isclaimedfis:

1. A color selection screen; embossments on said screen; facets. on said embossments; said embossments jbeingarranged so that eachfacet on eachembossmentis substantially parallel ,to

a corresponding faceton adjacent embossments whereby a plurality of .groups .of surfaces is formed; a fluorescentcoating on said screen, said coating beingcomposedof diiferentmaterials on said groups .ofv surfaces, each .of said materials beingadapted to..emit' light ofa dilferent color than the othersof said materials whenexcited by electrons; and ametallicllayer ,coveringsaid fluorescent coating, .said metallic layer being permeable .to electrons that. strike it essentially perpendicularly .and impermeable .to electrons striking it substantially tangentially.

v2.. In a color television system, a vacuum .tube

havinglascreen with .alfluorescent surface and a plurality of,.electron gunsfor generating electronbeams forscanning said .screen; embossments on oneside of said surface, said embossmentsforming aplurality of sets of fluorescent surfaces angularlydisposed with respect to, each .otherand positioned ,to bestruck respectively ,byindividual ones of said electron beams; and

metallic coating beingpermeable only to electrons striking it essentially perpendicularly; and

three electronguns located sothat the electrons fromeach one of saidguns strikes one of said portions substantially perpendicularly.

4..A ffluorescent screen comprising a lightpermeable plate embossed on onesurface with trihedral protuberances so arranged that each side of each of said protuberances is substantially parallel to one side of all other of said protuberances whereby the said surface is divided into three sets of substantially parallel planes; three types of fluorescent coatings, one type on each of said sets of planes, each of said types of coating ,having a naturalfluorescense in one of :the; three'-primary colors when excited-by electrons; and a metallic coating over said fluorescent coatings, said metallic coating being permeable to electrons only when struck thereby at an angle substantially normal to the plane thereof.

5. A fluorescent screen comprising a lightpermeableplateembossed on one surface with trihedral protuberances so arranged that each sideofzeach of; said protuberances is substantially parallel to one side of all other of said protuberances whereby the'said surface is divided into three-sets of substantially parallel planes; three types of fluorescent coatings, one type on each of said-setsof planeseachof said types of coatinghaving a natural fluorescence in ,oneof the three primary colors when excited by electrons; and a metalliccoating over saidffluorescent coatings, said metallic coating being permeable to electronsonly when struck thereby at an angle substantially normal to the, plane thereof; and a plurality of essentially coplanar lenses on the othersurface of said plate,.each of said lenses covering an area of the plate substantiallyequal to thearea of one of said trihedral protuberances.

6. In a ,color television system, a cathode ray tube having a fluorescent screen and a plurality of electron guns for generating electron beams for scanning said screen, one side of said screen beingembossed forming aplurality of, sets of fluorescent surfaces angularly disposed with respect to each other and positioned to be struck respectively by individual ones of said electron beams, and a metallic coating, over said fluorescent. screen,.said coating being permeable to electrons only when struck thereby at an angle substantially normal to the plane thereof.

STANLEY JIKOCH. ROBERT E; RUTHERFORD.

. REFERENCES CITED The following references-are of-record inthe file of this patent:

UNITED STATES PATENTS Number Name Date vRe. 22,734 Rosenthal Mar. 19, 1946 2,029,639 Schlesinger, Feb. 4, 1936 2,083,203 Schlesinger June.8, 1937 2,121,356 ,Knoll June21, 1938 2,170,944 Glass et al Aug. 29, 1939 2,180,957 Hollmann Nov. 21,1939 2,195,489 Iams Apr. 2,1940 2,201,245 'Ruska et a] '.May 21, 19.40 2,280,191 'I-Iergenrother Apr. 21, 1942 2,289,978 Malter, July 14, 1942 2,310,863 .Leverenz Feb. 9, 1943 2,312,792 ,Bamford .Mar. 2, 1943 2,337,980 ,Du Mont et al., Dec. 28, 1943 2,367,277 jHenroteau Jan. 16, 1945 2,415,311 'Szegho Feb.4, 1947 FOREIGN PATENTS Number Country Date 508,037 GreatBritain June 26, 1939 562,168 Great Britain June21, 1944

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