Color cathode-ray tube

• US 6,396,221 B1
• Filed: 09/15/2000
• Issued: 05/28/2002
• Est. Priority Date: 09/05/1997
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nagaoka, Masafumi, Kato, Shinichi, Shirai, Syoji, Uchida, Go
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): LEE, SHUN K
• Application Number:
  US09/662,910
• Time in Patent Office: 620 Days
• Field of Search: 315/382 313/382,449,414
• US Class Current: 315/382
• CPC Class Codes: H01J 2229/4841 Dynamic potentials
• CPC Class Codes: H01J 2229/4879 non-symmetric about field scanning axis
• CPC Class Codes: H01J 29/503 Three or more guns, the axes of which lay in a common plane

Abstract

A color cathode-ray tube including a main lens section comprising an anode to which an anode voltage is applied, and a focus electrode. The focus electrode has first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied which is obtained by superposing on a predetermined voltage a voltage that changes depending upon the deflecting amount of the electron beams. Between the first type of focus electrode group and the second type of focus electrode group are formed in a dynamic lens and an electrostatic quadrupole lens. Three electron beam passage holes are formed in the electrodes that form the dynamic lens and the centers for the outer electron beam passage holes in the first type of focus electrode group are deviated relative to the centers of the outer electron beam passage holes in the second type of focus electrode group in the horizontal direction. The electrostatic quadrupole lens exhibits different intensities for the outer electron beams relative to the center electron beam.

Claims

1. A color cathode-ray tube comprising at least a panel portion having a phosphor screen on an inner surface thereof, a neck portion, a funnel portion connecting said panel portion and said neck portion, an electron gun housed in said neck portion, and a deflection yoke for scanning electron beams on the phosphor screen;

wherein said electron gun includes;

a main lens section comprising an anode to which an anode voltage is applied, and focus electrode, said focus electrode having a first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied, said second focus voltage being obtained by superposing on a predetermined voltage a voltage that changes depending upon a deflecting amount of the electron beams;

between the first type of focus electrode group and the second type of focus electrode group at least two electron lenses being formed including a dynamic lens for focusing the electron beams in both the horizontal direction and the vertical direction and an electrostatic quadrupole lens;

three electron beam passage holes are formed in electrodes which form said dynamic lens and centers for outer electron beam passage holes in the first type of focus electrode group are deviated relative to centers of outer electron beam passage holes in the second type of focus electrode group in the horizontal direction; and

said electrostatic quadrupole lens exhibits different intensities for the outer electron beams relative to the center electron beam.

2. A color cathode-ray tube according to claim 1, wherein the centers of said outer electron beam passage holes in the first type of focus electrode forming said dynamic focus lens are deviated toward the center electron beam relative to the centers of the outer electron beam passage holes in the second type of focus electrode.

3. A color cathode-ray tube according to claim 1, wherein said electrostatic quadrupole lens exhibits a stronger intensity for the outer electron beams than the center electron beam.

4. A color cathode-ray tube according to claim 3, wherein a vertical dimension of said outer electron beam passage holes in the first type of focus electrode forming said quadrupole lens is larger than a vertical dimension of said center electron beam passage hole.

5. A color cathode-ray tube according to claim 3, wherein said center electron beam passage hole in the first type of focus electrode forming said quadrupole lens is substantially circular.

6. A color cathode-ray tube according to claim 1, wherein a value of a vertical dimension divided by a horizontal dimension of said center electron beam passage hole is smaller as compared with a value of a vertical dimension divided by a horizontal dimension of side electron beam passage holes in the first type of focus electrode forming said quadrupole lens.

7. A color cathode-ray tube according to claim 1, wherein a value of vertical dimension divided by a horizontal dimension of said center electron beam passage hole is larger as compared with a value of a vertical dimension divided by a horizontal dimension of side electron beam passage holes in the second type of focus electrode forming said quadrupole lens.

8. A color cathode-ray tube according to claim 1, wherein said anode has a center electron beam passage hole and side electron beam passage holes, one electrode opposing said anode of said focus electrode has a center electron beam passage hole and side electron beam passage holes, and wherein centers of outer electron beam passage holes of said anode are deviated away from the center electron beam relative to outer electron beam passage holes of said one electrode opposing said anode of said focus electrode.