Claims
- 1. A color cathode ray tube having an electron gun comprising:a beam forming region for generating a plurality of electron beams from cathodes and directing said plurality of electron beams toward a phosphor screen along initial paths in a horizontal plane; a main lens for focusing said plurality of electron beams on said phosphor screen; said main lens including a final lens configured so that said plurality of electron beams are focused in both a horizontal direction and a vertical direction, outer electron beams among said plurality of electron beams are deflected toward a trajectory of a center electron beam among said plurality of electron beams, and a lens strength thereof weakens with an increase in an amount of deflection of said plurality of electron beams; at least one correction lens for curvature of an image field located between said final lens and said beam forming region, and for focusing said plurality of electron beams in both the horizontal and vertical directions and weakening focusing action on said plurality of electron beams according to the increase in an amount of deflection of said plurality of electron beams; said at least one correction lens for curvature of the image field having an electrode configuration in which trajectories of outer electron beams among said plurality of election beams are deflected one of toward and away from a trajectory of a center electron beam among said plurality of electron beams according to the increase in an amount of deflection of said plurality of electron beams.
- 2. A color cathode ray tube according to claim 1, wherein a force exerted by said final lens to deflect the outer beams toward the center electron beam weakens with increasing deflection of said plurality of electron beams.
- 3. A color cathode ray tube according to claim 1, wherein said final lens is configured such that electron beam passage apertures associated with the outer electron beams form a non-axially-symmetric lens.
- 4. A color cathode ray tube according to claim 3, wherein center lines of outer electron beam passage apertures formed in two opposing electrodes forming said final lens are displaced from each other in said horizontal plane.
- 5. A color cathode ray tube according to claim 1, wherein each of two directly opposing and spaced ends of electrodes forming said final lens is formed with a single horizontally-elongated opening common for said plurality of electron beams.
- 6. A color cathode ray tube according to claim 5, wherein said final lens is comprised of two cylinder-like electrodes each formed with said single horizontally-elongated opening at an end thereof and each provided with a plate electrode having electron beam passage apertures therein.
- 7. A color cathode ray tube according to claim 6, wherein said plate electrode is retracted inwardly from said end of said cylinder-like electrode.
- 8. A color cathode ray tube according to claim 7, wherein said electron beam passage apertures are vertically elongated.
- 9. A color cathode ray tube according to claim 8, wherein said final lens focuses said plurality of electron beams stronger in a horizontal direction than in a vertical direction.
- 10. A color cathode ray tube according to claim 1, wherein said at least one correction lens for curvature of the image field has said electrode configuration in which the trajectories of said outer electron beams are deflected inwardly toward the trajectory of the center electron beam according to the increase in an amount of deflection of said plurality of electron beams.
- 11. A color cathode ray tube according to claim 10, wherein center lines of outer electron beam passage apertures formed in opposite surfaces of two electrodes forming said at least one correction lens for curvature of the image field are displaced from each other in said horizontal plane.
- 12. A color cathode ray tube according to claim 11, wherein said center lines of said outer electron beam passage apertures formed in one of said two electrodes supplied with a first voltage are displaced inwardly toward the trajectory of the center electron beam with respect to said center lines of said outer electron beam passage apertures formed in the other of said two electrodes supplied with a second voltage lower than said first voltage, in said horizontal plane.
- 13. A color cathode ray tube according to claim 1, wherein said at least one correction lens for curvature of the image field having an electrode configuration in which the trajectories of the outer electron beams are deflected toward the trajectory of the center electron beam according to the increase in an amount of deflection of said plurality of electron beams is located adjacent to said final lens.
- 14. A color cathode ray tube according to claim 1, wherein said at least one correction lens for curvature of the image field is located adjacent to said final lens.
- 15. A color cathode ray tube according to claim 1, wherein an electrode among a plurality of electrodes constituting said at least one correction lens for curvature of the image field has a fixed potential applied thereto and has a length of 1 to 2.5 times a diameter of electron beam passage apertures formed therein.
Priority Claims (1)
Number |
Date |
Country |
Kind |
6-167120 |
Jul 1994 |
JP |
|
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of U.S. application Ser. No. 09/012,450, filed Jan. 23, 1998 now U.S. Pat. No. 6,025,674, which is a continuation of U.S. application Ser. No. 08/808,037, filed Mar. 4, 1997, now U.S. Pat. No. 5,739,631, which is a continuation of U.S. application Ser. No. 08/504,139, filed Jul. 19, 1995, now U.S. Pat. No. 5,608,284, issued Mar. 4, 1997, the subject matter of which is incorporated by reference herein.
US Referenced Citations (10)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0 284 990 A2 |
Oct 1988 |
EP |
0511488 |
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Mar 1999 |
EP |
5-266822 |
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JP |
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WO |
Non-Patent Literature Citations (1)
Entry |
“Enhanced Elliptical Aperture Lens Gun for Color Picture Tubes”, S. Shirai, et al, 2320 Proceedings of the SAID, vol. 31/3, 1990, pp. 185-191. |
Continuations (3)
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Number |
Date |
Country |
Parent |
09/012450 |
Jan 1998 |
US |
Child |
09/433726 |
|
US |
Parent |
08/808037 |
Mar 1997 |
US |
Child |
09/012450 |
|
US |
Parent |
08/504139 |
Jul 1995 |
US |
Child |
08/808037 |
|
US |