Electric lamp and discharge devices – Cathode ray tube – Beam deflecting means
Patent
1994-07-06
1997-02-18
O'Shea, Sandra L.
Electric lamp and discharge devices
Cathode ray tube
Beam deflecting means
313495, 313496, 313497, 313493, H01J 2970, H01J 162
Patent
active
056043945
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a flat-type image display apparatus. More particularly, it relates to an improved image display apparatus with less luminance unevenness.
BACKGROUND ART
FIGS. 16 and 17 are, respectively, an exploded perspective view of a conventional flat-type image display apparatus as disclosed in, for example, Japanese Unexamined Patent Publications Nos. 226949/1991 and 184239/1988 and an enlarged, partially broken away view of a principal part of another example. In FIGS. 16 and 17, numeral 1 denotes string like hot cathodes each of which is connected to a support and emits electrons when energized, and numeral 3 denotes perforated cover electrodes each covering each string like hot cathode 1 and each elliptically shaped in section. Each cover electrode 3 has small apertures permitting electrons to pass therethrough and serves to lead electrons out of the corresponding string like hot cathode 1 when an appropriate potential is applied. An electron-emitting source 40 comprises the string like hot cathodes 1, perforated cover electrodes 3 and back electrodes 42 fixing the cover electrodes 3 arranged in parallel and each assuming a potential equal to that of the corresponding cover electrode 3. Numeral 8 denotes a front glass which is coated on the inner surface thereof with three types of luminous elements (not shown) in a dotted or striped manner and with an aluminum film (not shown) covering these luminous elements for electric conduction, the luminous elements being adapted to be excited by electrons emitted from the electron-emitting source 40 to emit light in respective colors, i.e., red, green and blue.
In such a configuration, an application of a voltage of about 5 to about 30 kV to the aluminum film of the front glass 8 causes electrons to accelerate and thereby the luminous elements (not shown) to be excited to emit light. Numeral 4 denotes a control electrode for permitting or shutting off the passage of electrons led out by each cover electrode 3 toward the front glass 8, the control electrode being interposed between the front glass 8 and the string like hot cathodes 1. Numeral 10 denotes a focusing electrode to be applied with a predetermined voltage for causing an electron beam having passed through an electron-pass aperture 4a of the control electrode 4 to pass through an electron-pass aperture 10a and to be focused upon the corresponding dot of the luminous element. As shown in FIG. 17, the control electrode 4 includes a surface-insulative substrate 5 having electron-pass apertures 4a corresponding to pixels formed on the front glass 8, for example, a surface-insulative substrate 5 formed by coating an etch-perforated metallic substrate with an insulating film, a first control electrode group 6A including metallic electrodes 6 which are patterned like stripes having electron-pass apertures and arranged on the lower side of the surface-insulative substrate 5, or on the electron-emitting source 40 side, corresponding to respective columns of pixels, and a second control electrode group 7A, similar to the former group, including metallic electrodes 7 which are patterned like stripes having electron-pass apertures and arranged on the upper side of the surface-insulative substrate 5 corresponding to respective rows of pixels. Each metallic electrode of the first and second control electrode groups 6A and 7A is formed of, for example, a nickel film. The first and second control electrode groups 6A and 7A are insulated from each other by a nickel-free portion existing within each electron-pass aperture though nickel penetrates thereinto from both sides. The first control electrode group 6A further includes isolation grooves 44, or nickel-free insulating grooves, which extend between adjacent electron-pass apertures 4a in the direction perpendicular to the string like hot cathode 1. Similarly, the second control electrode group 7A includes isolation grooves 45 extending in the direction perpendicular to the isolation grooves 44 of the first control electrode g
REFERENCES:
patent: 4804887 (1989-02-01), Miyama
patent: 4853586 (1989-08-01), Peters
patent: 4928041 (1990-05-01), Mayer et al.
patent: 4955681 (1990-09-01), Sekihara et al.
patent: 5134338 (1992-07-01), Shiratori
patent: 5189335 (1993-02-01), Sekihara
patent: 5191259 (1993-03-01), Hayashi
patent: 5202609 (1993-04-01), Tomii
Murakami Hidenobu
Saito Masato
Sakurai Kouichi
Shiroishi Tetsuya
Suzuki Ryo
Mitsubishi Denki & Kabushiki Kaisha
Ning John
O'Shea Sandra L.
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