Electric lamp and discharge devices – Cathode ray tube – Shadow mask – support or shield
Patent
1992-02-05
1994-05-03
Yusko, Donald J.
Electric lamp and discharge devices
Cathode ray tube
Shadow mask, support or shield
313403, H01J 2907
Patent
active
053090594
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention generally relates to color cathode ray tubes for use in a wide variety of display devices such as TV and so on, and, more particularly, to a color cathode ray tube of a Trinitron (registered trademark) type.
BACKGROUND ART
In a color cathode ray tube, a color selecting mechanism is provided in opposing relation to a color fluorescent screen to thereby cause an electron beam to land on predetermined fluorescent patterns.
In an ordinary color cathode ray tube, a shadow mask in which a single circular beam aperture, for example, is bored through a metal plate for a dot-shaped red, green and blue fluorescent triplet, for example, is provided in opposing relation to the color fluorescent screen as a color selecting mechanism. Such a shadow mask is supported to a frame by welding a circumferential portion of the metal plate molded as a dome shape by a press-treatment or the like. In this case, the shadow mask is supported to the frame without the application of tension so that, when a temperature of the shadow mask rises due to the electron beam scanned thereon, a so-called doming phenomenon which gives rise to a color misregistration is caused by the thermal expansion. To solve this problem, an Invar material having a low coefficient of thermal expansion is utilized as a mask material and the plate thickness thereof tends to increase in order to increase strength.
On the other hand, in the color cathode ray tube of the Trinitron type, three electron beams corresponding to red, green and blue colors are arranged on the horizontal plane and a color fluorescent screen is formed by arranging red, green and blue fluorescent stripes, each extending in the vertical direction, in a predetermined order in parallel. Also, an aperture grill, in which a large number of slits extended along the extending direction of the fluorescent stripes are formed, is disposed in an opposing relation to the fluorescent stripes as a color selecting mechanism.
In the ordinary aperture grill, as shown in FIG. 6 which is a schematic perspective view of an example of the ordinary aperture grill, a large number of slits 4 are bored through a metal plate 42 formed of a high purity iron thin plate having a thickness of 0.08 to 0.15 mm. This metal plate 42 is stretched over a frame 3. The frame 3 composed of a pair of opposing frame side members 3A, 3B an members 3C, 3D disposed across these frame side members 3A, 3B. The front end faces of the frame side members 3A, 3B are formed as curved surfaces forming the same cylindrical surface, and the metal plate 42 is stretched over these frame side members 3A and 3B.
When this metal plate 42 is stretched over and attached to the frame 3, the frame side members 3A and 3B of the frame 3 are drawn closer to each other by a turnbuckle. Then, under this condition, the metal plate 42 is secured at its edge portions corresponding to the respective ends of each slit 4 to the front end faces of the frame side members 3A and 3B by the welding-process. Thereafter, the external force applied to the frame 3 is released, whereby the band-shaped portions between the slits 4 on the metal plate 42 are extended in the extending direction of the slit 4 with a predetermined tension by a restitution force.
On the other hand, since the color cathode ray tube has recently become larger in size, the length of the band-shaped portion between the slits 4 of the metal plate 42 of the aperture grill 10 is increased so that, when an electron beam strikes the fluorescent screen, the band-shaped portion tends to vibrate due to vibration caused by sound, impulses or the like, which gives rise to problems such as occurrence of color misregistration or the like. Therefore, in order to suppress the vibration of the band-shaped portion, the thickness of the metal plate 42 is increased to increase rigidity, or the thickness of the material forming the frame 3 is increased to increase a resilient force which removes the above-mentioned distortion, thereby suppressing the vibration of the band-shaped por
REFERENCES:
patent: 4692660 (1987-09-01), Adler et al.
patent: 4926089 (1990-05-01), Moore
patent: 4942332 (1990-07-01), Adler et al.
patent: 5041756 (1991-08-01), Fairbanks
Kawase Mitsuhiro
Kume Hisao
Patel Nimesh
Sony Corporation
Yusko Donald J.
LandOfFree
Color cathode ray tube does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Color cathode ray tube, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color cathode ray tube will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2117148