Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
1999-04-05
2001-01-09
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S496000, C313S497000, C313S336000
Reexamination Certificate
active
06172456
ABSTRACT:
TECHNICAL FIELD
This invention relates flat-panel field emissions displays.
BACKGROUND OF THE INVENTION
Flat-panel displays are widely used to visually display information where the physical thickness and bulk of a conventional cathode ray tube is unacceptable or impractical. Portable electronic devices and systems have benefitted from the use of flat-panel displays, which require less space and result in a lighter, more compact display system than provided by conventional cathode ray tube technology.
The invention described below is concerned primarily with field emission flat-panel displays. In a field emission flat-panel display, an electron emitting cathode plate is separated from a display face or faceplate at a relatively small, uniform distance. The intervening space between these elements is evacuated. Field emission displays have the outward appearance of a CRT except that they are very thin. While being simple, they are also capable of very high resolutions. In some cases they can be assembled by use of technology already used in integrated circuit production.
Field emission flat-panel displays utilize field emission devices, in groups or individually, to emit electrons that energize a cathodoluminescent material deposited on a surface of a viewing screen or display faceplate. The emitted electrons originate from an emitter or cathode electrode at a region of geometric discontinuity having a sharp edge or tip. Electron emission is induced by application of potentials of appropriate polarization and magnitude to the various electrodes of the field emission device display, which are typically arranged in a two-dimensional matrix array.
Field emission display devices differ operationally from cathode ray tube displays in that information is not impressed onto the viewing screen by means of a scanned electron beam, but rather by selectively controlling the electron emission from individual emitters or select groups of emitters in an array. This is commonly known as “pixel addressing.”
It is important in field emission displays that the particle emitting surface of the electrode emitting cathode plate and the opposed display face be insulated from one another by a small distance across the full area of the display face. This is required to prevent electrical breakdown between the emitting surface and the display face. Furthermore, the spacing must be precisely uniform to assure uniform resolution, focus, and brightness.
In addition to uniform spacing of the display elements, it is also important to maintain the quality of the high vacuum typically required within such displays. According to the present invention, this is accomplished by providing of a getter in open communication with the evacuated space separating the particle emitting surface and the opposed display face. A getter is a chemically active substance such as metallic barium which removes traces of gas from otherwise evacuated spaces.
Many prior art field emission flat-panel displays use glass cathode plates. The invention described below, however, preferably utilizes a silicon or semiconductor substrate for its cathode or emitter plate. This allows conventional semiconductor processing techniques to be used in forming individual cathodes and addressing circuitry.
U.S. Pat. No. 4,923,421 to Brodie et al. describes one prior art display device utilizing a silicon cathode plate in a flat-panel display. Such has a transparent faceplate and a semiconductor backplate upon which cathodes are formed. The space between the faceplate and the backplate is evacuated. One problem with a device such as this is the maintenance of the required parallel spacing between the cathode plate and the faceplate. This problem is the result of the high vacuum inside the structure. This tends to bow the relatively thin semiconductor backing plate inward. To prevent such bowing, Brodie proposes a plurality of spacers interspersed between cathodes. While effective, such spacers are difficult to fabricate and interfere with cathode formation and placement.
Another problem with using a silicon backplate or cathode plate in conjunction with a glass faceplate is the difficulty of forming an adequate seal between the silicon and the glass for purposes of maintaining a vacuum within the display structure. Even when this problem is solved, valuable silicon real estate must be used for completing the seal. This reduces the number of cathode plates which can be fabricated from a single semiconductor wafer, and therefore adds to the cost of the display subsystem.
Further, present flat-panel display technology does not adequately address the problem of establishing electrical connections to the internal electrode circuits of a flat-panel displays. While the Brodie patent mentions “through-the-wafer” connections, these connections are difficult to manufacture and are detrimental to maintaining the desired vacuum within the flat-panel display.
The invention described below addresses each of the problems noted above, while achieving a simplicity which has been absent from prior designs.
REFERENCES:
patent: 3665238 (1972-05-01), Van Esdonk et al.
patent: 4387283 (1983-06-01), Peterson et al.
patent: 4769345 (1988-09-01), Butt et al.
patent: 4857161 (1989-08-01), Borel et al.
patent: 4857799 (1989-08-01), Spindt et al.
patent: 4923421 (1990-05-01), Brodie et al.
patent: 5015912 (1991-05-01), Spindt et al.
patent: 5063327 (1991-11-01), Brodie et al.
patent: 5075591 (1991-12-01), Holmberg
patent: 5140219 (1992-08-01), Kane
patent: 5151061 (1992-09-01), Sandhu
patent: 5157304 (1992-10-01), Kane et al.
patent: 5207607 (1993-05-01), Nagano et al.
patent: 5223766 (1993-06-01), Nakayama et al.
patent: 5249732 (1993-10-01), Thomas
patent: 5272413 (1993-12-01), Yamazaki et al.
patent: 5361079 (1994-11-01), Yamamato
patent: 5381039 (1995-01-01), Morrison
patent: 5424605 (1995-06-01), Lovoi
patent: 5520563 (1996-05-01), Wallace et al.
patent: 5525861 (1996-06-01), Banno et al.
patent: 5537738 (1996-07-01), Cathey et al.
patent: 5577944 (1996-11-01), Taylor
patent: 5587622 (1996-12-01), Mohacsi
patent: 5589731 (1996-12-01), Fahlen et al.
patent: 5612256 (1997-03-01), Stansbury
patent: 5614785 (1997-03-01), Wallace et al.
patent: 5653017 (1997-08-01), Cathey et al.
patent: 5760470 (1998-06-01), Stansbury
patent: 5766053 (1998-06-01), Cathey et al.
patent: 5786232 (1998-07-01), Stansbury
patent: 5910705 (1999-06-01), Cathey et al.
Montgomery, Clive Richard, “Flip Chip Assemblies Using Conventional Wire Bonding Apparatus and Commerically Available Dies,” ISHM '93 Proceedings, pp. 451-456.
IBM Technical Disclosure, “Direct Chip Bonding For Liquid Crystal Display”, vol. 34, No. 5, Oct. 1991, pp. 183-184.
“Liquid Crystal Display Products”, Product Brochure, Standish LCD, Division of Standish Industries, Inc., pp. 5-6.
“Process-Stabilized Extrude Bonding Wire and Ribbon”, Product Brochure, Hydrostatics Inc., Bethlehem PA, (Jun. 1991).
Kondoh, You et al. “A Subminiature CCD Module Using a New Assembly Technique”, IEICE Transactions, vol.E 74, No. 8 Aug. 1991.
Cohen, I.M. et al. “Ball Formation Processes in Alumium Bonding Wire”, Solid State Technology, pp. 89-92, Dec. 1985.
Levy, F. et al. “Phosphors for Full Color Microtips Fluorescent Displays”, pp. 20-23, IEEE, 1991.
Kang, Sa-Yoon et al. Physical and Fuzzy Logic Modeling of a Flip-Chip Thermocompression Bonding Process, Journal of Electronic Packaging, pp. 63-70, Mar. 1993.
Charles, Jr., H.K. “Electronic Materials Handbook—Vol. 1 Packaging”, Product Brochure, ASM International.
Cathey David A.
Watkins Charles
Gerike Matthew J.
Micro)n Technology, Inc.
Patel Nimeshkumar D.
Wells, St. John, Roberts Gregory & Matkin P.S.
LandOfFree
Field emission display does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Field emission display, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Field emission display will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2435419