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Color crt having shadow mask with vibration attenuator

Imported: 23 Feb '17 | Published: 22 Oct '02

Hideo Suzuki, Michiaki Watanabe, Yoshikazu Demi, Mitsunori Yokomakura

USPTO - Utility Patents

Abstract

A color cathode-ray tube that can attenuate vibration of an entire shadow mask positively with a simple structure. The color cathode-ray tube includes a frame-shaped mask frame and a shadow mask in which many apertures are formed in a flat plate, the shadow mask stretched and fixed in the mask frame in a condition in which a tension force is applied in one direction. The amplitude in the end portions of the shadow mask is not less than a certain amount relative to the amplitude in the center portion of the shadow mask, in a resonance of the shadow mask caused by a vibration propagated to the color cathode-ray tube. Furthermore, by providing vibration attenuators at the end portions of the shadow mask, vibrations at the end portions of the shadow mask are attenuated as the side surfaces of the shadow mask slide on the vibration attenuators. Thus, vibration of the entire shadow mask can be extinguished positively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an embodiment of an assembly of a shadow mask and a mask frame according to the present invention.

FIG. 2 illustrates an example of a condition of vibration of a shadow mask according to a first embodiment of the color cathode-ray tube of the present invention.

FIG. 3 illustrates a preferable pattern of a resonance of the shadow mask according to the first embodiment of the color cathode-ray tube of the present invention.

FIG. 4 illustrates another preferable pattern of a resonance of the shadow mask according to the first embodiment of the color cathode-ray tube of the present invention.

FIG. 5 illustrates a non-preferable pattern of vibration of a shadow mask of a color cathode-ray tube according to a comparative example.

FIG. 6 illustrates an example of the vibration condition of a shadow mask of a color cathode-ray tube according to a comparative example.

FIG. 7 illustrates an example of the vibration condition of a shadow mask in a color cathode-ray tube according to a comparative example.

FIG. 8 illustrates an example of the vibration condition of a shadow mask according to a second embodiment of the color cathode-ray tube of the present invention.

FIG. 9 is a perspective view showing an embodiment of an assembly of a shadow mask and a mask frame according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view taken along the line I—I of FIG.

9.

FIG. 11 is a perspective view showing an embodiment of an assembly of a shadow mask and a mask frame according to a fourth embodiment of the present invention.

FIG. 12 is a perspective view showing an embodiment of an assembly of a shadow mask and a mask frame according to a fifth embodiment of the present invention.

FIG. 13 is a perspective view showing an embodiment of an assembly of a shadow mask and a mask frame according to a sixth embodiment of the present invention.

FIG. 14 is a cross-sectional view taken along the line II—II of FIG.

13.

FIG. 15 is a cross-sectional view of an example of a conventional color cathode-ray tube.

FIG. 16 shows directions of tension in conventional color cathode-ray tubes.

Claims

1. A color cathode-ray tube comprising

2. The color cathode-ray tube according to claim 1, wherein the first vibration attenuator is inserted through a hole formed in the shadow mask.

3. The color cathode-ray tube according to claim 1, wherein the first vibration attenuator is a ring-shaped member.

4. The color cathode-ray tube according to claim 1, wherein the first vibration attenuator is a frame-shaped member.

5. The color cathode-ray tube according to claim 1, wherein the mass of the first vibration attenuator is in a range of 0.02×10

−3 to 5.0×10

−3 kg.

6. The color cathode-ray tube according to claim 1, wherein the first vibration attenuator is attached to a portion of the shadow mask where no aperture for passing an electron beam is formed.

7. The color cathode-ray tube according to claim 1, which is provided with a second vibration attenuator other than the first vibration attenuator for attenuating vibration of the first vibration attenuator by contacting with the first vibration attenuator when the first vibration attenuator is vibrating.

8. The color cathode-ray tube according to claim 1, wherein an amplitude in an end portion of the shadow mask in the direction perpendicular to the direction in which a tension is applied is not less than a certain amount relative to an amplitude in a center portion of the shadow mask, in a vibration mode of a seventh or less order for a resonance of the shadow mask caused by a vibration propagated to the color cathode-ray tube.

9. The color cathode-ray tube according to claim 8, wherein an amplitude in the end portion of the shadow mask is not less than 20% with respect to an amplitude in the center portion of the shadow mask.

10. The color cathode-ray tube according to claim 8, wherein a tension stress in the center portion of the shadow mask is larger than a tension stress in the end portion of the shadow mask.

11. The color cathode-ray tube according to claim 8, wherein when the tension stress in the center portion of the shadow mask is 1 and the tension stress in the end portion of the shadow mask is 2, an inequality

1≧1.12

is satisfied.

12. The color cathode-ray tube according to claim 8, wherein there is a maximum value of tension stress between the center portion and the end portion of the shadow mask.

13. The color cathode-ray tube according to claim 12, wherein when the tension stress in the center portion of the shadow mask is 1, the tension stress in the end portion of the shadow mask is 2, and the tension stress in an intermediate portion between the center portion and the end portion is 3, inequalities

3≧1.11,

2≧1,and

3≧2

are satisfied.