US3797934A - System and method for making multigraded tv masks - Google Patents

System and method for making multigraded tv masks Download PDF

Info

Publication number
US3797934A
US3797934A US00187171A US3797934DA US3797934A US 3797934 A US3797934 A US 3797934A US 00187171 A US00187171 A US 00187171A US 3797934D A US3797934D A US 3797934DA US 3797934 A US3797934 A US 3797934A
Authority
US
United States
Prior art keywords
light
diffuser
plate
openings
master
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00187171A
Inventor
G Miller
G Munter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Buckbee Mears Co
Original Assignee
Buckbee Mears Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Buckbee Mears Co filed Critical Buckbee Mears Co
Application granted granted Critical
Publication of US3797934A publication Critical patent/US3797934A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/02—Sensitometric processes, e.g. determining sensitivity, colour sensitivity, gradation, graininess, density; Making sensitometric wedges
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B15/00—Special procedures for taking photographs; Apparatus therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
    • H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0727—Aperture plate
    • H01J2229/075—Beam passing apertures, e.g. geometrical arrangements
    • H01J2229/0755—Beam passing apertures, e.g. geometrical arrangements characterised by aperture shape
    • H01J2229/0761—Uniaxial masks having parallel slit apertures, i.e. Trinitron type

Definitions

  • This invention relates generally to shadowmasks for colored television tubes and, more specifically, to a method and system of forming shadow masks having differently graded openings along the horizontal and vertical axis of the masks.
  • a shadow mask is located between the electron gun at the rear of the tube and the phosphor coated face plate at the front or viewing face of the tube.
  • the electron beam from the electron gun passes through the openings or apertures in the shadow mask and impinges upon a suitable color producing phosphor on the face plate.
  • the openings in the shadow 'mask may be circular, hexagonal or elongated.
  • the openings extend vertically from the bottom of the mask to the top of themask.
  • the width of the openings are smaller at a given vertical distance from the center of the mask than at the same given horizontal distance from the center of the mask. This requires having a predetermined grading of the width of the openings in a horizontal x axis and a different predetermined grading of the width of the openings in the vertical y axis.
  • the specific problem is how to produce a mask having a set of elongated openings that have a predetermined graded orientation in the x axis and'a predetermined different graded orientation in the mutually perpendicular y axis.
  • the openings in the shadow mask can vary from .006 to .003 inch with the openings spaced about .020 inch apart.
  • the present invention eliminates the costly and difficult intermediate step of preparing a multigraded negative pattern through such process as scribing and the like by using optical techniques that utilize an arcuate or curved diffuser of uniform thickness that diminishes the intensity of light projected through a non-graded pattern to produce a multigraded pattern on a plate located behind the non-graded pattern.
  • the present invention comprises a system having an arcuate shaped light diffuser of uniform thickness that diffuses light horizontally and vertically before transmitting the light through a plurality of nongraded openings onto a photosensitive plate. Because of the arcuate shaped light diffuser the light diffuses more in one axis than in the mutually perpendicular axis. This diffused light, when projected through a set of non-graded openings, produces a multigraded master image on a photosensitive plate which is located behind the non-graded image. The multigraded master image on the photosensitive plate can then be developed and printed to form a master pattern for photoprinting the multigraded image in photoresist on the shadow mask. Once the multigraded pattern has been formed on the mask the mask openings can be etched through conventional techniques.
  • FIG. 1 is a schematic view showing the components of the system for producing the multigraded mask.
  • FIG. 2 is a view showing the appearance of the mask on the photosensitive plate after exposure in the present system.
  • FIG. 1 shows, in schematic form, a system for producing a master with multigraded openings.
  • the system comprises a revolving light source 11, a bowed or arcuate light diffuser 12 which is the heart of the present system and a camera 20 which holds a focusing lens13, an aperture 10, a negative contact of a scribed or ruled master 14 and a photosensitive plate 16 located adjacent master 14.
  • adjacent is taken to mean that master 14 is near to plate 16 or at some small distance from plate 16 but not in contact with plate 16.
  • light source 11 comprises a conventional frosted bulb that is mounted in a socket that can be slowly rotated through 360 by a suitable means (not shown).
  • the purpose of having a rotating light source is to eliminate the difference in luminous intensity inherent in filament bulbs which would produce an unevenness in photosensitive plate 16 in addition to the desired gradient that is introduced into the pattern on plate 16.
  • an arcuate shaped light diffuser 12 of uniform thickness which comprises the heart of the present invention.
  • Light diffuser 12 comprises a sheet of flexible material such as acrylic resin which has been bent in an arcuate shape through the application of force on opposite ends of the sheet.
  • the present invention utilizes a sheet of acrylic resin which is held in shape by force but it is apparent that the acrylic resin material could also be preformed in an arcuate shape so that it would not be necessary to support the edges in compression.
  • acrylic resin is preferred for the light diffuser material, it is apparent that other types of material could equally well be used.
  • This type of light diffuser is not a lens and should not be confused with a lens.
  • a lens has a varying thickness from the center to the outside edge whereas light diffuser 12, in contrast, has a uniform thickness from the center to the outside edge.
  • the diffuser located in front of light source 11, it diffuses the light causing a variation in the luminous intensity as it passes through the diffuser.
  • the bow in the light diffuser located along the vertical axis, it decreases the luminous intensity of the light more rapidly along the vertical axis than along the horizontal axis.
  • the center of photosensitive plate 16 receives the highest luminous intensity with the edges receiving the lowest luminous intensity.
  • the luminous intensity of photosensitive plate 16 would vary uniformly in a direction radially outward from the center of photographic plate 16.
  • light diffuser 12 along optic axis 21, it causes the light to diffuse at a different rate along the vertical axis thus further diminishing the intensity of the light on the top and bottom half of photosensitive plate 16.
  • the amount of light diffusion can be controlled by varying the choice of the light diffusers, that is, the greater the curve the greater the diffusion and, consequently, the steeper the grade of the opening. Also, it will be apparent that the diffusion of the light can be further varied in the mutually perpendicular axis by placing a second bowed diffuser along the optical axis in series with diffuser 12. It is further envisioned that for certain application diffusers may be .made in a hemispherical or oval shape to produce the desired light diffusion.
  • the operator places his non-graded master 14 which may be formed through a scribed process or the like in front of a photosensitive plate 16 located at the back of the camera 20.
  • the operator activates light source 11 and also starts rotation of light source 11 about optic axis 21.
  • the light from source 11 projects through diffuser 12, lens 13 and aperture and onto the non-graded master plate 14.
  • a portion of light passes through the opening in master plate 14 and onto photosensitive plate 16.
  • the variation of the luminous intensity on the photosensitive plate 16 causes the pattern of parallel elongated opening in master 14 to become distorted into the appearance shown in FIG. 2.
  • the acrylic resin diffuser 12 is a translucent white material as opposed to a clear acrylic resin.
  • the purpose of using a translucent white material is to reduce the source concentration of light present with a conventional source such as a light bulb or an elongated tube type lamp.
  • a typical material having a suitable degree of opacity for use is manufactured by Rohm Haas Company under the designation Plexiglas 2447. This example is given as being merely illustrative of a typical material that could be used and no limitation is intended thereto.
  • it is preferred to use an acrylic resin material with a predetermined degree of opacity that transmits only a portion of the light it is apparent that a clear arcuate shaped acrylic resin diffuser with a suitable light dispensing source could also be used.
  • the suitable light source could constitute a conventional light bulb located behind a flat sheet of material having a suitable degree of opacity, such as the aforementioned acrylic resin.
  • materials other than acrylic resin could be used but commercially available acrylic resins have been found to have both the desired degree of opacity and the uniformity of opacity throughout the sheet.
  • An apparatus for producing a multigraded image comprising: a source of light energy located along an optical axis; said source of light energy including means for rotating the light source about said axis for at least 360 during exposure of the photosensitive plate; a diffuser for decreasing the intensity of the light projectible through the diffuser in a predetermined direction, said light diffuser having a uniform thickness and an arcuate shape, said diffuser located along said optical axis; a master plate having a set of openings and located along said optical axis on the opposite side of said diffuser from said source of light; and a photosensitive plate located adjacent said master plate and on the opposite side from said diffuser so that said light source exposes the portions of the photosensitive plate that are not shielded by said master plate in proportion to the intensity of the light arriving at said plate.

Abstract

A method for forming a multigraded negative by utilizing an arcuate shaped light diffuser of uniform thickness.

Description

United States Patent [191 Miller et al. v
[ Mar. 19, 1974 SYSTEM AND METHOD FOR MAKING MULTIGRADED TV MASKS [75] Inventors: Gerald M. Miller, Sylvania, Ohio;
George M. Munter, Roseville, Minn.
[73] Assignee: Buckbee-Mears Company, St. Paul,
Minn.
[22] Filed: Oct. 6, 1971 [21] Appl; No.: 187,171
Related US. Application Data [63] Continuation-impart of Ser. No. 838.459, July 2,
1969, abandoned.
51 Int. ci. G03b 27/26 [58] Field of Search 95/1 5;] U. S l, .sgggyni [56] v References Cited UNITED STATES PATENTS 2.603.133 7/1952 Strong 95/1 3.008.390 11/1961 Heil 95/1 3.309.973 3/1967 Engler 95/1 Primary Examiner-John M. Horan Attorney, Agent, 0r FormJacobs0n and Johnson [5 7 ABSTRACT A method for forming a multigraded negative by utilizing an arcuate shaped light diffuser of uniform thickness.
3 Claims, 2 Drawing Figures PATENTEDMAR 1 9 m4 8,797,934
Y i T M L L Fig. 2
INVENTCR GERALD M. MILLER GEORGE M. MUIVT'ER ATTORNEYS 1 ".1- SYSTEM AND METHOD FOR MAKING MULTIGRADED TV MASKS CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of our application filed July 2, 1969, Ser. No. 838,459, now abandoned, and assigned to the same assignee as the present invention. I
BACKGROUND OF THE INVENTION 1. Field of the Invention. This invention relates generally to shadowmasks for colored television tubes and, more specifically, to a method and system of forming shadow masks having differently graded openings along the horizontal and vertical axis of the masks.
2. Description of the Prior Art. In a colored picture tube a shadow mask is located between the electron gun at the rear of the tube and the phosphor coated face plate at the front or viewing face of the tube. The electron beam from the electron gun passes through the openings or apertures in the shadow mask and impinges upon a suitable color producing phosphor on the face plate. Typically, the openings in the shadow 'mask may be circular, hexagonal or elongated. In a mask having elongated openings, the openings extend vertically from the bottom of the mask to the top of themask. In masks having elongated openings, it is necessary to have the width of the openings at the center of the mask larger than the width of the openings at the edges of the mask. In addition, it is necessary that the width of the openings are smaller at a given vertical distance from the center of the mask than at the same given horizontal distance from the center of the mask. This requires having a predetermined grading of the width of the openings in a horizontal x axis and a different predetermined grading of the width of the openings in the vertical y axis.
Briefly, the specific problem is how to produce a mask having a set of elongated openings that have a predetermined graded orientation in the x axis and'a predetermined different graded orientation in the mutually perpendicular y axis.
Typically, the openings in the shadow mask can vary from .006 to .003 inch with the openings spaced about .020 inch apart. With these small dimensions and the number of graded openings required for each shadow mask, it is apparent that it would be extremely costly and difficult to produce a mask that has the proper number of openings as well as the desired grading through such techniques as scribing a multigraded pattern on a negative and then using photoprinting techniques to form a multigraded pattern in photoresist on the mask. However, once the multigraded pattern had been printed in photoresist on the mask, the mask could be etchedusing well known etching techniques.
The present invention eliminates the costly and difficult intermediate step of preparing a multigraded negative pattern through such process as scribing and the like by using optical techniques that utilize an arcuate or curved diffuser of uniform thickness that diminishes the intensity of light projected through a non-graded pattern to produce a multigraded pattern on a plate located behind the non-graded pattern.
BRIEF SUMMARY OF THE INVENTION Briefly, the present invention comprises a system having an arcuate shaped light diffuser of uniform thickness that diffuses light horizontally and vertically before transmitting the light through a plurality of nongraded openings onto a photosensitive plate. Because of the arcuate shaped light diffuser the light diffuses more in one axis than in the mutually perpendicular axis. This diffused light, when projected through a set of non-graded openings, produces a multigraded master image on a photosensitive plate which is located behind the non-graded image. The multigraded master image on the photosensitive plate can then be developed and printed to form a master pattern for photoprinting the multigraded image in photoresist on the shadow mask. Once the multigraded pattern has been formed on the mask the mask openings can be etched through conventional techniques.
BRIEF SUMMARY OF THE DRAWINGS FIG. 1 is a schematic view showing the components of the system for producing the multigraded mask; and
FIG. 2 is a view showing the appearance of the mask on the photosensitive plate after exposure in the present system.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 shows, in schematic form, a system for producing a master with multigraded openings. The system comprises a revolving light source 11, a bowed or arcuate light diffuser 12 which is the heart of the present system and a camera 20 which holds a focusing lens13, an aperture 10, a negative contact of a scribed or ruled master 14 and a photosensitive plate 16 located adjacent master 14. For the purposes of this invention, adjacent is taken to mean that master 14 is near to plate 16 or at some small distance from plate 16 but not in contact with plate 16.
Referring to the individual components of the system, light source 11 comprises a conventional frosted bulb that is mounted in a socket that can be slowly rotated through 360 by a suitable means (not shown). The purpose of having a rotating light source is to eliminate the difference in luminous intensity inherent in filament bulbs which would produce an unevenness in photosensitive plate 16 in addition to the desired gradient that is introduced into the pattern on plate 16. Located next to the light source 11 is an arcuate shaped light diffuser 12 of uniform thickness which comprises the heart of the present invention. Light diffuser 12 comprises a sheet of flexible material such as acrylic resin which has been bent in an arcuate shape through the application of force on opposite ends of the sheet. The present invention utilizes a sheet of acrylic resin which is held in shape by force but it is apparent that the acrylic resin material could also be preformed in an arcuate shape so that it would not be necessary to support the edges in compression. Although acrylic resin is preferred for the light diffuser material, it is apparent that other types of material could equally well be used.
This type of light diffuser is not a lens and should not be confused with a lens. A lens has a varying thickness from the center to the outside edge whereas light diffuser 12, in contrast, has a uniform thickness from the center to the outside edge. By having the diffuser located in front of light source 11, it diffuses the light causing a variation in the luminous intensity as it passes through the diffuser. With the bow in the light diffuser located along the vertical axis, it decreases the luminous intensity of the light more rapidly along the vertical axis than along the horizontal axis. Thus the center of photosensitive plate 16 receives the highest luminous intensity with the edges receiving the lowest luminous intensity.
in the absence of light difi'user 12, the luminous intensity of photosensitive plate 16 would vary uniformly in a direction radially outward from the center of photographic plate 16. However, by placing light diffuser 12 along optic axis 21, it causes the light to diffuse at a different rate along the vertical axis thus further diminishing the intensity of the light on the top and bottom half of photosensitive plate 16.
The amount of light diffusion can be controlled by varying the choice of the light diffusers, that is, the greater the curve the greater the diffusion and, consequently, the steeper the grade of the opening. Also, it will be apparent that the diffusion of the light can be further varied in the mutually perpendicular axis by placing a second bowed diffuser along the optical axis in series with diffuser 12. It is further envisioned that for certain application diffusers may be .made in a hemispherical or oval shape to produce the desired light diffusion.
In operation of the system, the operator places his non-graded master 14 which may be formed through a scribed process or the like in front of a photosensitive plate 16 located at the back of the camera 20. Next, the operator activates light source 11 and also starts rotation of light source 11 about optic axis 21. The light from source 11 projects through diffuser 12, lens 13 and aperture and onto the non-graded master plate 14. A portion of light passes through the opening in master plate 14 and onto photosensitive plate 16. The variation of the luminous intensity on the photosensitive plate 16 causes the pattern of parallel elongated opening in master 14 to become distorted into the appearance shown in FIG. 2.
While the present invention is shown and described in conjunction with a master utilizing a set of elongated openings, it will be apparent to those skilled in the art that the present invention could equally well be used to grade round holes, hexagonal holes or any other type of pattern requiring a multigraded mask.
Also, in the present invention the acrylic resin diffuser 12 is a translucent white material as opposed to a clear acrylic resin. The purpose of using a translucent white material is to reduce the source concentration of light present with a conventional source such as a light bulb or an elongated tube type lamp. A typical material having a suitable degree of opacity for use is manufactured by Rohm Haas Company under the designation Plexiglas 2447. This example is given as being merely illustrative of a typical material that could be used and no limitation is intended thereto. Although it is preferred to use an acrylic resin material with a predetermined degree of opacity that transmits only a portion of the light, it is apparent that a clear arcuate shaped acrylic resin diffuser with a suitable light dispensing source could also be used. in this latter arrangement the suitable light source could constitute a conventional light bulb located behind a flat sheet of material having a suitable degree of opacity, such as the aforementioned acrylic resin. Furthermore, materials other than acrylic resin could be used but commercially available acrylic resins have been found to have both the desired degree of opacity and the uniformity of opacity throughout the sheet.
We claim:
1. An apparatus for producing a multigraded image comprising: a source of light energy located along an optical axis; said source of light energy including means for rotating the light source about said axis for at least 360 during exposure of the photosensitive plate; a diffuser for decreasing the intensity of the light projectible through the diffuser in a predetermined direction, said light diffuser having a uniform thickness and an arcuate shape, said diffuser located along said optical axis; a master plate having a set of openings and located along said optical axis on the opposite side of said diffuser from said source of light; and a photosensitive plate located adjacent said master plate and on the opposite side from said diffuser so that said light source exposes the portions of the photosensitive plate that are not shielded by said master plate in proportion to the intensity of the light arriving at said plate.
2. The apparatus of claim 1 wherein said master contains a plurality of parallel elongated openings of uniform width.
3. The apparatus of claim 1 wherein the set of openings in said master are of uniform width.

Claims (3)

1. An apparatus for producing a multigraded image comprising: a source of light energy located along an optical axis; said source of light energy including means for rotating the light source about said axis for at least 360* during exposure of the photosensitive plate; a diffuser for decreasing the intensity of the light projectible through the diffuser in a predetermined direction, said light diffuser having a uniform thickness and an arcuate shape, said diffuser located along said optical axis; a master plate having a set of openings and located along said optical axis on the opposite side of said diffuser from said source of light; and a photosensitive plate located adjacent said master plate and on the opposite side from said diffuser so that said light source exposes the portions of the photosensitive plate that are not shielded by said master plate in proportion to the intensity of the light arriving at said plate.
2. The apparatus of claim 1 wherein said master contains a plurality of parallel elongated openings of uniform width.
3. The apparatus of claim 1 wherein the set of openings in said master are of uniform width.
US00187171A 1971-10-06 1971-10-06 System and method for making multigraded tv masks Expired - Lifetime US3797934A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US18717171A 1971-10-06 1971-10-06

Publications (1)

Publication Number Publication Date
US3797934A true US3797934A (en) 1974-03-19

Family

ID=22687875

Family Applications (1)

Application Number Title Priority Date Filing Date
US00187171A Expired - Lifetime US3797934A (en) 1971-10-06 1971-10-06 System and method for making multigraded tv masks

Country Status (1)

Country Link
US (1) US3797934A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961847A (en) * 1975-03-06 1976-06-08 Xerox Corporation Arcuate screen for an electrophotographic printing machine
US4132470A (en) * 1976-03-17 1979-01-02 U.S. Philips Corporation Exposure device for the manufacture of display screens of color television display tubes and display tube manufactured by means of such a device
EP0042869A1 (en) * 1979-12-31 1982-01-06 Ncr Co Method and apparatus for fabricating a translucent graded density medium.
US4539297A (en) * 1982-03-05 1985-09-03 The Regents Of The University Of California Ultraviolet imaging method and apparatus
US6363636B1 (en) * 1996-05-17 2002-04-02 Dimplex North America Limited Flame simulating assembly and components therefor
US7121690B1 (en) * 2004-02-26 2006-10-17 Advanced Optical Technologies, Llc Constructive occlusion with a transmissive component
US20180084172A1 (en) * 2016-09-21 2018-03-22 General Electric Company Assembly and method for glare elimination

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2603133A (en) * 1948-12-13 1952-07-15 Gen Electric Apparatus for making optical wedges
US3008390A (en) * 1955-12-27 1961-11-14 Gen Electric Method and apparatus for fabricating screens for television picture tubes
US3309973A (en) * 1964-10-26 1967-03-21 Ernest F Engler Light blocking tool for photographic printing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2603133A (en) * 1948-12-13 1952-07-15 Gen Electric Apparatus for making optical wedges
US3008390A (en) * 1955-12-27 1961-11-14 Gen Electric Method and apparatus for fabricating screens for television picture tubes
US3309973A (en) * 1964-10-26 1967-03-21 Ernest F Engler Light blocking tool for photographic printing

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961847A (en) * 1975-03-06 1976-06-08 Xerox Corporation Arcuate screen for an electrophotographic printing machine
US4132470A (en) * 1976-03-17 1979-01-02 U.S. Philips Corporation Exposure device for the manufacture of display screens of color television display tubes and display tube manufactured by means of such a device
EP0042869A1 (en) * 1979-12-31 1982-01-06 Ncr Co Method and apparatus for fabricating a translucent graded density medium.
EP0042869B1 (en) * 1979-12-31 1985-03-27 Ncr Corporation Method and apparatus for fabricating a translucent graded density medium
US4539297A (en) * 1982-03-05 1985-09-03 The Regents Of The University Of California Ultraviolet imaging method and apparatus
US6363636B1 (en) * 1996-05-17 2002-04-02 Dimplex North America Limited Flame simulating assembly and components therefor
US7121690B1 (en) * 2004-02-26 2006-10-17 Advanced Optical Technologies, Llc Constructive occlusion with a transmissive component
US20180084172A1 (en) * 2016-09-21 2018-03-22 General Electric Company Assembly and method for glare elimination
US10334179B2 (en) * 2016-09-21 2019-06-25 Current Lighting Solutions, Llc Assembly and method for glare elimination

Similar Documents

Publication Publication Date Title
US3661580A (en) Photographic method for producing a cathode-ray tube screen structure
US3302016A (en) Optical collimating system
US3797934A (en) System and method for making multigraded tv masks
ES384065A1 (en) Photographic method for producing a cathode ray tube screen structure
US3736848A (en) Method of preparing the screen of a colour television picture tube and device performing the method
US4647519A (en) Negative-working photoresist method of making rear-projection television screen viewing surface
GB1566891A (en) Exposing photosensitive material on the screen of a colour cathode-ray tube
US4132470A (en) Exposure device for the manufacture of display screens of color television display tubes and display tube manufactured by means of such a device
US2870010A (en) Method of manufacturing electrical apparatus
US3279311A (en) Device for producing an even distribution of light on a copying frame
US3854815A (en) Graphic arts camera flashing attachments
US3198097A (en) Illuminating apparatus
EP0135234B1 (en) A negative-working photoresist composition for use on a polymethyl methacrylate surface
US2941457A (en) Apparatus for use in the manufacture of mosaic screens for color-kinescopes, etc.
US2100148A (en) Apparatus for producing images
US3848983A (en) Optical system for providing uniform exposure of a photosensitive surface
US3993487A (en) Method for manufacture of color television picture tubes using rotating light source
US3616732A (en) Aperture mask optical system
CA1205664A (en) Half tone screen exposure apparatus
US3953621A (en) Process of forming cathode ray tube screens
US3563147A (en) Master camera for producing components for integral photography
US1675783A (en) Photograph-enlarging light box
MY111421A (en) Method of forming phosphor screen of color cathode-ray tube and exposure apparatus
US3809558A (en) Exposure devices utilized to manufacture color picture tubes
JP2527426B2 (en) Color TV picture tube