US3784282A - Correcting lens used to form fluorescent screens of colour television receiving tubes - Google Patents

Correcting lens used to form fluorescent screens of colour television receiving tubes Download PDF

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Publication number
US3784282A
US3784282A US00228639A US3784282DA US3784282A US 3784282 A US3784282 A US 3784282A US 00228639 A US00228639 A US 00228639A US 3784282D A US3784282D A US 3784282DA US 3784282 A US3784282 A US 3784282A
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regions
lens
correcting lens
effective
inclination angles
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Expired - Lifetime
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US00228639A
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E Yamazaki
K Maruyama
T Ueda
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Hitachi Ltd
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Hitachi Ltd
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
    • 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
    • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
    • H01J9/22—Applying luminescent coatings
    • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
    • H01J9/2271—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines by photographic processes
    • H01J9/2272—Devices for carrying out the processes, e.g. light houses
    • H01J9/2273—Auxiliary lenses and filters

Definitions

  • Phosphor dots are generally formed by exposing to light the fluorescent screen by utilizing an exposure device schematically illustrated in FIG. 1 of the accompanying drawing.
  • the exposure device shown in FIG. 1 comprises a source of light 2 and a correcting lens 3 which is used for the purpose of causing the locus of the light beam emanated from the source of light 2 to approximate to that of the scanning electron beam.
  • a panel including a shadow mask 4 of a colour cathode ray tube Above the correcting lens 3 is mounted a panel including a shadow mask 4 of a colour cathode ray tube.
  • the panel 5 is exposed to the light beam from the source of light 2 through the correcting lens 3 and through the perforations of the shadow mask 4.
  • the surface of the lens is formed as a curved surface of an extremely complicated construction having a number of regions of different curvatures.
  • the surface of a prior art correcting lens has generally been in the form of a continuously curved surface.
  • a lens of such a continuously curved surface the purpose of causing the locus of the light beam to approximate to that of the scanning electron beam can not be fully attained so that it is impossible to perfectly match the phosphor dots and the scanning electron beam spots over the entire inner surface of the panel.
  • a colour television receiving tube with a fluorescent screen formed by usinga prior art correcting lens having a continuously curved surface has a drawback of accompanying a colour shading, thus impairing the quality of the reproduced image.
  • the crosssectional configuration of the prior art correcting lens resembles saw teeth having effective regions A,, A, of relatively small inclination angles with respect to the horizontal or the bottom surface of the lens and regions D D, of large inclination angles with respect to the horizontal and interconnecting adjacent regions A,, A,
  • light beams B 1 and B, passing through the effective regions A,, A travel straightforwardly in the prescribed direction C C
  • the beam passing through the connecting regions D D travels in the direction F which is quite different from the prescribed direction.
  • the beam E directed to the unwanted direction F will pass through a perforation of the shadow mask and impinge upon an unwanted portion of the inner surface of the panel thus forming a phosphor dot thereat.
  • the colour television receiving tube having a fluorescent screen with phosphor dots formed by using the correcting lens de scribed above is also formed with phosphor dots at unwanted portions so that colour mixing of the picture is unavoidable.
  • the object of this invention is to provide an improved correcting lens which can form phosphor dots in a regular pattern on the inner surface of the panel of a colour television receiving tube and can prevent phosphor dots from being formed at the unwanted portions thus eliminating colour mixing of the reproduced image.
  • a correcting lens adapted to be used for forming a fluorescent screen of a colour television receiving tube, the lens being of the type wherein the effective area of the lens through which the exposure light beams pass is divided into a plurality of discontinuous effective regions of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective regions are interconnected by connecting regions of larger inclination angles with respect to the bottom surface, characterized in that light intercepting films are applied to the. connecting regions.
  • FIG. 1 shows a longitudinal sectional view of a typical apparatus for exposing the panel of a colour television receiving tube
  • FIG. 2 is a plane view of a prior art correcting lens utilized in the exposure apparatus shown in FIG. 1;
  • FIG. 3 shows a cross-section of the lens shown in FIG. 2 taken along a line III-III;
  • FIG. 4 is an enlarged cross-sectional view of a portion of the lens shown in FIGS. 2 and 3 explaining the travel of exposure light beams and
  • FIG. 5 shows an enlarged cross-section of a portion of the lens embodying the invention.
  • regions D,, D, interconnecting adjacent effective regions A A of relatively small inclination angles with respect to the horizontal or the bottom surface of the correcting lens 6 are coated with films 7 of opaque material.
  • Efl'ective regions A A may be flat surfaces of different inclination angles or curved surfaces of different radii of curvature.
  • the tube having a fluorescent screen fabricated by using the correcting lens embodying the invention is completely free from colour mixing.
  • Substantially the same object can also be attained by applying films of translucent substance on the connecting regions D in which case the light beams transmitting through such translucent films are greatly weakened.
  • novel correcting lens can also be used to form phosphors in the form of stripes.
  • a single correcting lens adapted to be used for refracting light for forming the entire area of a fluorescent screen of a colour television receiving tube, said lens being of the type wherein the effective refracting surface of the lens through which the useful exposure light beams pass is divided into a plurality of discontinuous effective elemental regions with two dimensional boundaries, said elemental regions having surfaces of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective elemental regions interconnected at said boundaries by contiguous connecting ineffective refracting regions of larger surface inclination angles with respect to the bottom surface, the improvement which comprises light intercepting films applied only to said connecting ineffective regions of larger surface inclination for substantially reducing the intensity of erroneously refracted beams.

Abstract

In a correcting lens utilized to form the fluorescent screen of a colour television receiving tube, the lens being of the type wherein the effective surface of the lens through which the effective light beams pass is divided into a plurality of discontinuous effective regions of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective regions are interconnected by connecting regions of larger inclination angles with respect to the bottom surface, opaque or translucent films are applied to the connecting regions.

Description

SR N
United state& a: aecna 1' 1 Yamazaki et al.
vow: vH
CORRECTING LENS USED TO FORM FLUORESCENT SCREENS OF COLOUR TELEVISION RECEIVING TUBES Inventors: Eiichi Yamazaki, lchihara; Koichi Maruyama; Toshio Ueda, both of Mobara, all of Japan Assignee: Hitachi, Ltd., Tokyo, Japan Filed: Feb. 23, 1972 Appl. No.: 228,639
Foreign Application Priority Data Mar. 5, 197] Japan 46/13665 US. Cl. 350/175 R, 95/l R, 350/205, 350/213 Int. Cl. G02!) 3/00 Field of Search 350/205, l89, 193, 350/194, 211, 213,175 R References Cited UNITED STATES PATENTS l0/l966 Ramberg et al 350/205 UX Jan. 8, 1974 3,628,850 12/1971 Yamazaki et al 350/189 X 3,134.02] 5/l964 Flake... 350/205 X Primary Examiner-John K. Corbin Attorney-Charles E. Pfund and Chittick, Thompson Pfund 5 7] ABSTRACT 5 Claims, 5 Drawing Figures PATENTED JAN 81974 v ll wifI SREEI 1 RF 2 F/ei/ PRIDR ART PRIOR ART PATENTEUJAN 81w SHEET 2 OF 2 PRIOR ART 1 CORRECTING LENS USED TO FORM FLUORESCENT SCREENS OE COLOUR TELEVISION RECEIVING TUBES BACKGROUND OF THE INVENTION This invention relates to a correcting lens utilized to correct the locus of a light beam adapted to form phosphor dots of colour television receiving tubes.
It is usual to form the fluorescent screen of a shadow mask type colour television receiving tube by photographic technique wherein a plurality of trios of phosphor dots of red, blue and green are applied in a regular pattern on the inner surface of the panel of the tube. Phosphor dots are generally formed by exposing to light the fluorescent screen by utilizing an exposure device schematically illustrated in FIG. 1 of the accompanying drawing. The exposure device shown in FIG. 1 comprises a source of light 2 and a correcting lens 3 which is used for the purpose of causing the locus of the light beam emanated from the source of light 2 to approximate to that of the scanning electron beam. Above the correcting lens 3 is mounted a panel including a shadow mask 4 of a colour cathode ray tube. Thus, the panel 5 is exposed to the light beam from the source of light 2 through the correcting lens 3 and through the perforations of the shadow mask 4.
As above described, since the purpose of the correcting lens 3 is to cause the locus of the light beam to ap proximate to that of the electron beam the surface of the lens is formed as a curved surface of an extremely complicated construction having a number of regions of different curvatures.
The surface of a prior art correcting lens has generally been in the form of a continuously curved surface. With a lens of such a continuously curved surface the purpose of causing the locus of the light beam to approximate to that of the scanning electron beam can not be fully attained so that it is impossible to perfectly match the phosphor dots and the scanning electron beam spots over the entire inner surface of the panel. For this reason, in a colour television receiving tube with a fluorescent screen formed by usinga prior art correcting lens having a continuously curved surface has a drawback of accompanying a colour shading, thus impairing the quality of the reproduced image.
To solve this problem it has been proposed a correcting lens having a discontinuously curved surface wherein the surface of the lens if divided into a plurality of regions and the respective regions are finished to provide predetermined flat surfaces or curved surfaces, as shown in FIGS. 2 and 3.
Although such a correcting lens having a discontinuously curved surface can cause the locus of the exposure light beam to substantially match with that of the scanning electron beam, it has created the following problems.
More particularly, as shown in FIG. 4 the crosssectional configuration of the prior art correcting lens resembles saw teeth having effective regions A,, A, of relatively small inclination angles with respect to the horizontal or the bottom surface of the lens and regions D D, of large inclination angles with respect to the horizontal and interconnecting adjacent regions A,, A, Although light beams B 1 and B, passing through the effective regions A,, A, travel straightforwardly in the prescribed direction C C, the beam passing through the connecting regions D D, travels in the direction F which is quite different from the prescribed direction. Accordingly, the beam E directed to the unwanted direction F will pass through a perforation of the shadow mask and impinge upon an unwanted portion of the inner surface of the panel thus forming a phosphor dot thereat. In this manner, the colour television receiving tube having a fluorescent screen with phosphor dots formed by using the correcting lens de scribed above is also formed with phosphor dots at unwanted portions so that colour mixing of the picture is unavoidable.
SUMMARY OF THE INVENTION Accordingly, it is the object of this invention is to provide an improved correcting lens which can form phosphor dots in a regular pattern on the inner surface of the panel of a colour television receiving tube and can prevent phosphor dots from being formed at the unwanted portions thus eliminating colour mixing of the reproduced image.
According to this invention, there is provided a correcting lens adapted to be used for forming a fluorescent screen of a colour television receiving tube, the lens being of the type wherein the effective area of the lens through which the exposure light beams pass is divided into a plurality of discontinuous effective regions of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective regions are interconnected by connecting regions of larger inclination angles with respect to the bottom surface, characterized in that light intercepting films are applied to the. connecting regions.
BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawing:
FIG. 1 shows a longitudinal sectional view of a typical apparatus for exposing the panel of a colour television receiving tube;
FIG. 2 is a plane view of a prior art correcting lens utilized in the exposure apparatus shown in FIG. 1;
FIG. 3 shows a cross-section of the lens shown in FIG. 2 taken along a line III-III;
FIG. 4 is an enlarged cross-sectional view of a portion of the lens shown in FIGS. 2 and 3 explaining the travel of exposure light beams and FIG. 5 shows an enlarged cross-section of a portion of the lens embodying the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT A preperred embodiment of the invention will now be described with reference to FIG. 5 in which portions corresponding to those shown in FIG. 4 are designated by the same reference characters. According to this invention, the regions D,, D, interconnecting adjacent effective regions A A of relatively small inclination angles with respect to the horizontal or the bottom surface of the correcting lens 6 are coated with films 7 of opaque material. Efl'ective regions A A, may be flat surfaces of different inclination angles or curved surfaces of different radii of curvature.
With this construction, exposure light beams impinging upon the connecting regions which otherwise would be directed to unwanted portions of the face plate as above described are intercepted by the films 7 of opaque substance with the result that only the beams passed through the effective regions A A, are
transmitted in the prescribed directions to form phosphor dots on the inner surface of the face plate at the desired portions thereof. ln other words, it is possible to prevent phosphor dots from being formed at unwanted portions. Thus, the tube having a fluorescent screen fabricated by using the correcting lens embodying the invention is completely free from colour mixing.
Substantially the same object can also be attained by applying films of translucent substance on the connecting regions D in which case the light beams transmitting through such translucent films are greatly weakened.
It is to be understood that the novel correcting lens can also be used to form phosphors in the form of stripes.
What is claimed is:
1. In a single correcting lens adapted to be used for refracting light for forming the entire area of a fluorescent screen of a colour television receiving tube, said lens being of the type wherein the effective refracting surface of the lens through which the useful exposure light beams pass is divided into a plurality of discontinuous effective elemental regions with two dimensional boundaries, said elemental regions having surfaces of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective elemental regions interconnected at said boundaries by contiguous connecting ineffective refracting regions of larger surface inclination angles with respect to the bottom surface, the improvement which comprises light intercepting films applied only to said connecting ineffective regions of larger surface inclination for substantially reducing the intensity of erroneously refracted beams.
2. The correcting lens as claimed in claim 1 wherein said discontinuous effective regions are in the form of flat surfaces of different inclination angles.
3. The correcting lens as claimed in claim 1 wherein said discontinuous effective regions are in the form of curved surfaces of different radii of curvature.
4. The correcting lens as claimed in claim 1 wherein said light intercepting films are made of opaque substance.
5. The correcting lens as claimed in claim 1 wherein said light intercepting films are made of translucent substance.

Claims (5)

1. In a single correcting lens adapted to be used for refracting light for forming the entire area of a fluorescent screen of a colour television receiving tube, said lens being of the type wherein the effective refracting surface of the lens through which the useful exposure light beams pass is divided into a plurality of discontinuous effective elemental regions with two dimensional boundaries, said elemental regions having surfaces of relatively small inclination angles with respect to the bottom surface of the lens and the adjacent effective elemental regions interconnected at said boundaries by contiguous connecting ineffective refracting regions of larger surface inclination angles with respect to the bottom surface, the improvement which comprises light intercepting films applied only to said connecting ineffective regions of larger surface inclination for substantially reducing the intensity of erroneously refracted beams.
2. The correcting lens as claimed in claim 1 wherein said discontinuous effective regions are in the form of flat surfaces of different inclination angles.
3. The correcting lens as claimed in claim 1 wherein said discontinuous effective regions are in the form of curved surfaces of different radii of curvature.
4. The correcting lens as claimed in claim 1 wherein said light intercepting films are made of opaque substance.
5. The correcting lens as claimed in claim 1 wherein said light intercepting films are made of translucent substance.
US00228639A 1971-03-05 1972-02-23 Correcting lens used to form fluorescent screens of colour television receiving tubes Expired - Lifetime US3784282A (en)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50123448A (en) * 1974-03-15 1975-09-27
JPS50125755A (en) * 1974-03-19 1975-10-03
US3953209A (en) * 1973-08-20 1976-04-27 Rca Corporation Method for preparing supplemental filter for lighthouse
US4514040A (en) * 1982-03-11 1985-04-30 Societa' Italiana Vetro-Siv-S.P.A. Prismatic refractor for concentrating solar energy on a suitable collecting surface, of fixed position with respect to time
EP0173503A2 (en) * 1984-08-20 1986-03-05 Roxor Corporation Eliminations of internal reflections and deffractions from junctures in and at the periphery of, a segmented mirror
US4621898A (en) * 1983-03-17 1986-11-11 Allied Corporation Directional optical filter
US4630905A (en) * 1981-02-10 1986-12-23 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
US4632524A (en) * 1984-08-20 1986-12-30 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of a segmented mirror
US4641933A (en) * 1984-08-20 1987-02-10 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
US4674850A (en) * 1984-08-20 1987-06-23 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
JPS63125802U (en) * 1987-02-09 1988-08-17
US5751387A (en) * 1995-07-28 1998-05-12 Fujitsu Limited Fresnel lens and liquid crystal display device
US5801889A (en) * 1995-08-16 1998-09-01 Eastman Kodak Company Technique to eliminate scattered light in diffractive optical elements
US6211932B1 (en) 1995-07-28 2001-04-03 Fujitsu Limited Fresnel lens and liquid crystal display device
US6310733B1 (en) * 1996-08-16 2001-10-30 Eugene Dolgoff Optical elements and methods for their manufacture

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49145455U (en) * 1973-04-12 1974-12-16
US3782253A (en) * 1973-05-02 1974-01-01 Rca Corp Color television picture tube screening method
JPS542612Y2 (en) * 1973-11-10 1979-02-03
JPS522314U (en) * 1975-06-24 1977-01-08
JPS6077941U (en) * 1983-11-02 1985-05-31 三菱電機株式会社 Air conditioner piping connection structure
JPS60113475U (en) * 1984-01-05 1985-07-31 三菱重工業株式会社 air conditioner

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Publication number Priority date Publication date Assignee Title
US3134021A (en) * 1959-08-01 1964-05-19 Zeiss Ikon Ag Photoelectric exposure meters with light ray limiters
US3279340A (en) * 1964-03-19 1966-10-18 Rca Corp Art of making color-phosphor mosaic screens
US3628850A (en) * 1970-02-24 1971-12-21 Hitachi Ltd Correcting lens

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3385184A (en) * 1964-03-19 1968-05-28 Rca Corp Optical system for use in making color-phosphor mosaic screens

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3134021A (en) * 1959-08-01 1964-05-19 Zeiss Ikon Ag Photoelectric exposure meters with light ray limiters
US3279340A (en) * 1964-03-19 1966-10-18 Rca Corp Art of making color-phosphor mosaic screens
US3628850A (en) * 1970-02-24 1971-12-21 Hitachi Ltd Correcting lens

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953209A (en) * 1973-08-20 1976-04-27 Rca Corporation Method for preparing supplemental filter for lighthouse
JPS5712961B2 (en) * 1974-03-15 1982-03-13
JPS50123448A (en) * 1974-03-15 1975-09-27
JPS50125755A (en) * 1974-03-19 1975-10-03
US4630905A (en) * 1981-02-10 1986-12-23 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
US4514040A (en) * 1982-03-11 1985-04-30 Societa' Italiana Vetro-Siv-S.P.A. Prismatic refractor for concentrating solar energy on a suitable collecting surface, of fixed position with respect to time
US4609266A (en) * 1982-06-07 1986-09-02 Roxor Corporation Elimination of internal reflections and diffractions from junctures in and at the periphery of, a segmented mirror
US4621898A (en) * 1983-03-17 1986-11-11 Allied Corporation Directional optical filter
EP0173503A3 (en) * 1984-08-20 1988-08-31 Roxor Corporation Eliminations of internal reflections and deffractions from junctures in and at the periphery of, a segmented mirror
EP0173503A2 (en) * 1984-08-20 1986-03-05 Roxor Corporation Eliminations of internal reflections and deffractions from junctures in and at the periphery of, a segmented mirror
US4632524A (en) * 1984-08-20 1986-12-30 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of a segmented mirror
US4641933A (en) * 1984-08-20 1987-02-10 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
US4674850A (en) * 1984-08-20 1987-06-23 Roxor Corporation Elimination of internal reflections and diffractions from junctures in, and at the periphery of, a segmented mirror
JPS63125802U (en) * 1987-02-09 1988-08-17
JPH0637362Y2 (en) 1987-02-09 1994-09-28 カシオ計算機株式会社 LCD projector
US5751387A (en) * 1995-07-28 1998-05-12 Fujitsu Limited Fresnel lens and liquid crystal display device
US6211932B1 (en) 1995-07-28 2001-04-03 Fujitsu Limited Fresnel lens and liquid crystal display device
US5801889A (en) * 1995-08-16 1998-09-01 Eastman Kodak Company Technique to eliminate scattered light in diffractive optical elements
US6310733B1 (en) * 1996-08-16 2001-10-30 Eugene Dolgoff Optical elements and methods for their manufacture

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Publication number Publication date
DE2210727A1 (en) 1972-09-14
DE2210727B2 (en) 1977-06-16
JPS4721552U (en) 1972-11-10
FR2128352A1 (en) 1972-10-20
FR2128352B1 (en) 1975-10-24
GB1323540A (en) 1973-07-18

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