US2767457A

US2767457A - Color kinescopes and methods of making same

Info

Publication number: US2767457A
Application number: US466016A
Authority: US
Inventors: David W Epstein
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1954-11-01
Filing date: 1954-11-01
Publication date: 1956-10-23
Anticipated expiration: 1973-10-23

Description

Oct. 23, 1956 V w, EPSTEIN 2,767,457

COLOR KINESCOPES AND METHODS OF MAKING SAME Filed Nov. 1, 1954 i :5 Sheets-Sheet 1 0 INVENTOR. 5 0 9100 Wffisri/zv Oct. 23, 1956 D. w. EPSTEIN 2,767,457

COLOR KINESCOPEZS AND METHODS OF MAKING SAME Filed NOV. 1, 1954 3 Sheets-Sheet 2 INVENTOR. Q4 W0 W 5 5mm 4 oils/5V 1956 D. w. EPSTEIN KINESCOPES AND METHODS OF MAKING SAME Filed NOV. 1, 1954 -3 Sheets-Sheet 3 INVENTOR. pfi'V/D W6 5 TE/N 2,767,457 Patented Get. 23, 1956 COLOR KINESCOPES AND METHODS OF MAKING SAME David W. Epstein, Princeton, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application November 1, 1954, Serial N 0. 466,016 15 Claims. (Cl. 29-25.13)

This invention relates to improvements in the art of manufacturing color kinescopes and other cathode ray tubes of the type having a plane-of-defiection and containing a screen unit comprising a mask containing a multiplicity of systematically arranged apertures through which beam electrons pass along different angularly related paths in their transit from the plane-of-deflection to selected ones of metallized dot-like or line-like elemental phosphor areas on the target surface of a nearby screen.

One of the problems encountered in manufacturing a screen for use in color kinescopes of the type briefly described above, and for analogous tubes, has been the problem of depositing the phosphor particles in the dotlike or line-like elemental areas. One method of applying the phosphor particles which has been used heretofore is the direct photographic method wherein the different color emitting phosphors are laid down, one at a time, on the screen-plate. In this method a color emitting phosphor, as well as a photosensitive emulsion, is introduced into the tube and is exposed to a point source of light through the mask which exposes the emulsion in a particular pattern. When this step has been completed the mask is removed and after development of the exposed areas of emulsion, the emulsion and phosphor adhere to the screen-plate, while the emulsion which was not exposed as well as the corresponding phosphor particles are removed. The process is then repeated for the remaining two colors. In the direct photographic methd the screen unit must be disassembled several times, for the purpose of sensitizing the separately photographed red, blue, and green phosphor patterns of the screen, and subsequently reassembled prior to aligning the unit with a battery of electron guns in the tube in which the screen is to be utilized.

Accordingly, a principal object of this invention is to provide an improved cathode ray tube wherein access may be had to a foundation surface for a color screen through the envelope wall.

Another object of this invention is to provide an improved method of depositing phosphor particles wherein the particles are inserted through the walls of the envelope.

A further object of this invention is to provide a new method of and means for applying an electron permeable metal coating of substantially uniform thickness through an apertured mesh to a permanently mounted screen.

A still further object of this invention is to provide a. new method of settling color emitting phosphor particles through a mask and onto a support plate wherein excess phosphor particles may be removed from both the mask and the support plate.

Stated generally, the foregoing and other objects are there is provided means for inserting the phosphor particles and, or the photosensitive emulsion, through the wall of an envelope having permanently sealed therein an apertured mask. The materials are inserted into a space between the mask and the screen support plate.

A method of manufacturing is provided such that, when the direct photographic method of applying phosphor particles is employed, there is sufficient room to utilize a' high energy light source. When an electron sensitive mosaic pattern is to be provided With an electron transparent metallic layer, means are provided to produce a uniform layer of the metallic material, from a large source, through the apertured mask.

The invention is described in greater detail in connection with the accompanying three sheets of drawings, wherein:

Fig. 1 is a fragmentary sectional view of an envelope for a kinescope, having sealed therein an apertured mask, in the process of having a screen unit applied therein in accordance with the principles of this invention;

Figures 2 through 4 are fragmentary sectional views of further steps in the manufacture of the tube shown in Fig. l in accordance with this invention;

Fig. 5 is a longitudinal sectional view of a completed tube in accordance with this invention; and,

Fig. 6 is a fragmentary sectional view of an embodiment of a kinescope tube in accordance with this invention.

Referring now to the drawings in detail, Fig. 1 shows a partial sectional view of an envelope 11 for a tri-color kinescope having permanently sealed therein an apertured mask 16. The mask 16 is supported adjacent to,

a glass face plate, or screen, 14. In accordance with this invention the mask 16 may be supported within the envelope 11 prior to the sealing of face plate 14 to the cone portion 13 of envelope 11; The glass face plate 14 may be of any desired shape, e. g. circular or rectangular, and curvature, e. g. fiat or spherical. In the instant case the glass face plate 14 is in the form of a circular section of a spherical shell. The face plate 14 is sealedto a lip 12 on the cone portion 13 of envelope 11. Any of the conventional glass-to-metal seals may be utilized for sealing the face plate 14 to the lip 12.

The mask 16 may be of any type of conducting material, and preferably includes some type of temperature compen sation means such as hinges 17 to insure that the predetermined relationship between the mask 16 and face plate 14 is maintained during the operation of the tube.

achieved in accordance with this invention by permanently When, as in the instant case, the phosphor material is to be laid down directly on the inner surface of the curved face plate 14, the mask 16 is appropriately curved. In accordance with this invention a temperature compensated mask 16 is permanently bonded to the inner walls of cone 13. This bond may be made by a weld between a flat portion 19 of mask 16 and the inner surface of the metallic cone 13. It is also within the contemplation of this invention to permanently bond the mask 16 to the inner walls of cone 13 by other well-known means, such as support pins or ridges (not shown). The mask may be made of a copper-nickel alloy of approximately copper and the balance nickel.

Generally, it will be found to be advantageous to bond the mask 16 to the inner periphery of cone portion 13. prior to the sealing of the glass face plate 14 to the lip 12. In accordance with this invention, color emitting phosphor particles are deposited in any of the conventional patterns, i. e. dot-like or line-like patterns, after the mask 16 has been permanently sealed into the cone portion 13 of envelope 11. When the mask 16 has I well-known in the art. The aluminum coating is a continuous and is an even coating due to the large size of the evaporator 53, irrespective of the shadowing eifect of the mask 16.

After the conductive coating 55 has been applied to the filming lacquer 40, the layer of filming lacquer is baked out of the envelope and the conductive coating 55 provides a smooth surface over the color emitting phosphor particles v34, 35, and 36. The backing out of filming lacquer 40 also removes any of the filming lacquer material that may have been deposited on mask 16. When this step has been completed the cone 13 may be sealed to a funnel 58 having sealed therein a battery of electron guns 59, 60, and 61. The funnel 58 may be aligned with the cone 13 by well-known means such as alignment pins 31 (shown in Fig. 2), on the believed portion of cone 13. The funnel 58 may be sealed to the metallic cone 13 by any of the well-known glass-to-metal seals.

As seen from Fig. 5 the completed tube has a planeof-deflection for the three electron beams 62, provided by deflection yoke 57, each of which corresponds to the exact location of the point light source 30 in one of its locations shown in Fig. 2. Thus, the electron beams 62 from guns 59, 60, and 61 each strike one of the arrays of color emitting phosphors 34, 3'5, and 36 which are arranged in the conventional hexagonal pattern of red, blue, and green. =Each triad group of phosphors is arranged behind an aperture 20 in the mask 16. When the tube 10 has been completed the tubulation 28 may be utilized for exhausting the envelope 11 and may be pinched olf by any of the well-known low temperature sealing methods for such an element.

Referring now to Fig. 6 there is shown a partial sectional view of an embodiment of this invention comprising a glass envelope 63 for use as a tri-color television tube. As in the embodiment described in Figures 1 through 5 there is provided between a permanently 'secured mask 16' and a face plate 14 a tubulation 65 which may be utilized for inserting the color emitting phosphor particles and emulsion as previously described. The mask 16' is bonded to support pins 67 which are bonded within the cap portion 69 of envelope 63. When the mask is affixed into cap 69, the cap is sealed by means of seal 71 to a cone 70. As in the metal tube the mask 16' is temperature compensating and the entire process of manufacturing the tube occurs after the mask 16' has been sealed into the cap portion 69 and the cap sealed to the cone portion of the envelope 63. The process for completing the tube is substantially the same as that previously described.

As should be obvious to those skilled'in the art this invention provides a method of and means for manufacturing a color television tube after the mask and face plate are sealed to the cone portion of an envelope. The features of this invention permit tube manufacturers to obtain the combination of a cone, face plate, and mask from an envelope vendor, either glass or metal, and complete the tube by economical methods.

What is claimed isz 1. Method of depositing color emitting phosphors on a screen plate of a cathode ray tube of the type including an apertured mask spaced from said screen plate, said method including the step of applying said phosphors onto said screen plate through a wall of the envelope of said tube at a point intermediate said screen plate and said apertured mask.

2. Method of making a cathode-ray tube of the kind having an envelope containing a plane-of-defiection and a target-assembly comprising a mask spaced from a foundation surface of a phosphor screen, said mask containing a multiplicity of apertures systematically arranged in a pattern to define a target area through which an electron-beam normally passes from one of three substantially fixed points in said plane-of-deflection to preselected ones of the elemental areas of a similar pattern on said foundation surface of said screen, said envelope in:

ing an open neck-portion through which access may be had to said points in said plane-of-deflection, said method comprising; permanently securing said mask and said foundation surface in spaced relationship within the main chamber of said envelope, inserting a color emitting phosphor into said envelope, evenly distributing said phosp hor on said foundation surface, inserting a photosensitive emulsion through an opening in the wall of said envelope and into said space between said mask and said foundation plate, evenly distributing said emulsion on said phosphor, removably locating a projector in said open neck portion of said envelope in a position whereat the outlet of said projector coincides with one of said fixed points in said plane-of-deflection, projecting along a multiplicity of angul'arly related straight paths, from said outlet, emanations capable of passing through said maskapertures and of recording upon said target surface the pate-r11 of said apertures whereby said emulsion is de-- veloped in said pattern, removing said projector from said neck, removing the undeveloped portions of said emulsion and the corresponding phosphor particles through said opening, repeating said steps utilizing a second and a third color emitting phosphor and a second and a third of said substantially fixed points, Wetting the array of color emitting phosphor particles, spraying a filming lacquer onto said phosphor particles through the apertures in said mask, evaporating an electron pervious conductive film onto said lacquer and through the apertures in said mask, baking said envelope to remove said lacquer, and mounting three sources of beam-electrons in said neck in a position whereat the beam from each of said sources is in line with one of said fixed points in said plane-of, deflection.

3. The method of claim 2 as applied to the manufacture of a tri-color kinescope, and wherein the step of projecting emanations through said mask from said projector is repeated with the outlet of the projector located, successively, at each of the three points in the plane-ofdeflection each of which is peculiar to one of the three color emitting phosphors of said tri-color kinescope.

4. A sub-assembly for use in the manufacture of a cathode-ray tube of the color kinescope variety, said sub assembly comprising a cone. portion of an envelope, a

transparent screenplate forming a closed end on said cone portion and adapted to support electron sensitive material on the inner surface thereof, an apertured electrode permanently secured in said envelope and spaced from said screen-plate, and means through the wall of said envelope and opening into said space between said apertured elec: trode and said screen plate for inserting said electron Sen sitive material onto said screen plate.

5. A sub-assembly as in claim 4 wherein said cone is metallic and said means includes a hollow metallic tubulation of the type capable of being pinched off to form a low temperature seal.

6. A sub-assembly as in claim 4 wherein said cone is glass and said means includes a hollow tubulation adapted to be sealed after said electron sensitive material is in; serted.

7. Method of making a cathode=ray tube comprising an envelope containing a target-assembly comprising an electrode containing a multiplicity of apertures system= ati-cally arranged in a pattern to define a target area through which an electron-beam normally passes from one of three substantially fixed points in a planeof-deflection to pro-selected ones of the elemental areas of a similar pattern on a screen spaced from said electrode, said envelope having an open neck-portion through which access may be had to said point in said plane-of-deflection, said method comprising; permanently seeming said apertured electrode and said foundation surface in spaced relationship within the main chamber of said envelope, inserting a color emitting phosphor into said envelope through an opening into said space and through the wall of said envelope, evenly distributing said phosphor on said foundation surface, inserting a photosensitive emulsion into said envelope through said opening, evenly dis: tributing saidemulsion on said phosphor, removably locating a projector in said open neck portion of said envelope in a position whereat the outlet of said projector coincides with one, of said fixed points in said plane-ofdeflection, projecting along a multiplicity of angularly related straight paths, from said outlet, emanations capable of passing through said mask-apertures and of recording upon said target surface the pattern of said apertures whereby said emulsion is developed in said pattern, removing said projector from said neck, removing the undeveloped portions of said emulsion and the corresponding phosphor particles through said opening, repeating said steps utilizing a second and third of said substantially fixed points, wetting the resultant array of color emitting phosphor particles, spraying a filming lacquer onto said phosphor particles through the apertures in said mask, evaporating an electron pervious conductive film onto said lacquer and through the apertures in said mask, baking said envelope to remove said lacquer, and mounting three sources of beam-electrons in said neck in a position whereat the beam from each of said sources is in line with, one of said fixed points in said plane-of-deflection.

8. Method of making a cathode-ray tube comprising an envelope containing a target-assembly comprising an apertured electrode spaced from a foundation surface of a phosphor screen, said apertured electrode containing a multiplicity of apertures systematically arranged in a pattern to define a target area through which an electronbeam normally passes to pro-selected elemental areas on said foundation surface; said method comprising; permanently securing said apertured electrode and said foundation surface in spaced relationship within the top cap of said envelope, securing a cone portion of said envelope to said top cap, inserting a color emitting phosphor into said envelope through an aperture in said top cap opening into said space between said apertured electrode and said foundation surface, evenly distributing said phosphoron said foundation surface, inserting a photosensitive emulsion into said envelope through said opening, evenly distributing said emulsion on said phosphor, developing said emulsion in a pattern, and removing the undeveloped portions of said emulsion and the excess phosphor particles through said opening.

9. Method of making a cathode-ray tube comprising an envelope containing an apertured electrode spaced from a foundation surface of a nearby screen; said method comprising; permanently securing said apertured electrode and said foundation surface in spaced-apart relationship within the, main chamber of said envelope, inserting a color emitting phosphor into said envelope through an opening in the wall of said envelope and into said space between said apertured electrode and said foundation surface, inserting a photosensitive emulsion into said envelope through said opening, and projecting light from a source through the apertures in said apertured electrode for developing said emulsion in a pattern.

10. Method of making a cathode-ray tube comprising anenvelope containing a mask electrode spaced from a foundation surface of a phosphor screen, said method comprising; permanently securing said mask and said foundation surface in spaced-apart relationship .within the main cha mber of said envelope, inserting a color emitting phosphor into said envelope through an opening in said envelope and into said space between said mask and said foundation surface, inserting a photosensitive emulsion into saidenvelope through said opening, removably locating a projector in an open neck portion of said envelope in a position whereat the outlet of said projector coincides with a fixed point. inthe plane-of-defiection of said tube, projecting along a multiplicity of angularly related straight paths, from said outlet, light capable of passing through said mask-apertures and of recording upon said target surface the pattern ,of said apertures whereby said emulsion is developed in said pattern, removing said pro- 'ector from said neck, removing the undeveloped portions of said emulsion and the corresponding phosphor particles, repeating said stepstutilizing a second and third color emitting phosphor and a second and a third substantially fixedpoint, wetting the array of color emitting phosphor particles, spraying a filming lacquer onto said phosphor particles through the apertures in said mask, evaporating an electron pervious conductive film onto said lacquer and through the apertures in said mask, baking said envelope to remove said lacquer, and mounting electron beam producing means in said neck in a position whereat at least a portion of an electron beam is in line with each of said fixed points in said plane-of-defiection.

11. Method of making a cathode-ray tube comprising an envelope containing an apertured mask electrode spaced from a foundation surface for a phosphor screen, said method comprising; permanently securing said mask andsaid foundation surface in spaced relationship within the main chamber of a cathode-ray tube-envelope, settling a color emitting phosphor into said envelope through the apertures in said mask, introducing a photosensitive emulsion through-the wall of said envelope into the space between said mask and said surface, securing said phosphor-onto said foundation surface in a pattern similar to the pattern of the apertures in said mask, removing the unsecured portions of said phosphor particles from said surface and from said mask, repeating said steps utilizing a second and thirdcolor emitting phosphor, spraying a filming lacquer onto said phosphor particles through the apertures in said mask, evaporating an electron pcrvious conductive film ontosaid lacquer and through the apertures in saidmask, baking said envelope to remove said lacquer, and mounting three sourcesof beam-electrons in said neck in a position whereat the beam from each of said sources is in line with one of said fixed points in said plane-of-defiection.

l2. Amethod as in claim 11 wherein said unsecured phosphor particles are washed from said mask and said foundation surface.

13. Amethod as in claim 11 wherein said unsecured phosphor particles are removed through the wall of said envelope between said mask and said foundation surface.

14.. A sub-assembly for use in the manufacture of a cathode-ray tube comprising an envelope including a transparent screen-plate having a target surface area adapted to support an electron-sensitive target, a mask mounted in permanently fixed spaced-relation with respect to said screen-plate, and said envelope having at least one aperture therein opening into the space between said screen-plate and said mask.

15. The invention as set forth in claim 14 further comprisinga hollow tubular member sealed to said envelope and surrounding said aperture, and said tubular member being a material of the type adapted to be pinched ofif to form a low temperature seal.

No references cited.