Computer graphics processing and selective visual display system – Plural physical display element control system – Segmented display elements
Reexamination Certificate
1998-03-20
2001-07-17
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Segmented display elements
C345S050000, C349S139000, C430S020000, C430S416000
Reexamination Certificate
active
06262697
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to commonly-assigned U.S. patent application Ser. No. 08/961,059 filed Oct. 30, 1997, entitled “Display Apparatus Using Light Patternable Conductive Traces” by Stanley W. Stephenson; commonly-assigned U.S. patent application Ser. No. 08/961,056 filed Oct. 30, 1997, entitled “Single Sheet Display Having Patternable Conductive Traces” by Stanley W. Stephenson; commonly-assigned U.S. patent application Ser. No. 08/990,891 filed Dec. 15, 1997, entitled “Method of Producing a Display Having Patternable Conductive Traces” by Stanley W. Stephenson; commonly-assigned U.S. patent application Ser. No. 08/990,853 filed Dec. 15, 1997, entitled “A Sheet Having Patternable Conductive Traces for Use in a Display” by Stanley W. Stephenson; and commonly-assigned U.S. patent application Ser. No. 09/027,321 filed Feb. 20, 1998, entitled “Selectively Presenting Viewable and Conductive Images” by Stanley W. Stephenson, the disclosures of which are incorporated herein by reference.
FIELD OF THE INVENTION
The field of invention relates to displays in which images can be selectively presented to a viewer.
BACKGROUND OF THE INVENTION
Flat panel displays can be fabricated using many techniques. Typical embodiments are disclosed in
Liquid Crystal Flat Panel Displays
by William C. O'Mara (Chapman & Hall, New York, N.Y. 1993) and other similar publications. These displays use transparent glass plates as substrates, and electrical traces are sputtered in a pattern of parallel lines that form a first set of conductive traces. A transparent conductor such as Indium Tin Oxide (ITO) is sputtered over the traces to disperse an electrical charge across transparent areas not blocked by the traces. A second substrate is similarly coated with a set of traces having a transparent conductive layer.
Layers are applied over the substrates and patterned to orient liquid crystals in twisted nematic (TN) or super-twisted-nematic (STN) configurations. The two substrates are spaced apart and the space between the two substrates is filled with a liquid crystal material. Pairs of conductors from either set are selected and energized to alter the optical transmission properties of the liquid crystal material.
In another embodiment, the traces do not define an orthogonal grid, but are organized to form alpha-numeric displays or graphic images. In a further embodiment, an active display on a transparent substrate is sputtered or printed and uses memory elements to continuously drive each display element depending on information written to the memory element. In another embodiment, disclosed in SID DIGEST 90, article 12.6, the liquid crystal material can be polymerically dispersed to form a Liquid Crystal Polymer Matrix (LCPC). LCPCs are typically disposed in ultra-violet polymerized acrylic polymers. The liquid crystals are homogenized into the polymer, and the emulsion is coated onto a substrate. Ultra violet light is applied to the emulsion. The emulsion hardens, and bubbles of liquid crystal material are held in a rigid polymeric matrix.
Reflective liquid crystal polymer matrix displays are disclosed in U.S. Pat. No. 4,435,047. A first sheet has transparent ITO conductive areas and a second sheet has electrically conductive inks printed on display areas. The sheets can be glass, but in practice have been formed of Mylar polyester. A dispersion of liquid crystal material in a binder is coated on the first sheet, and the second sheet is pressed onto the liquid crystal material. Electrical charges applied to opposing conductive areas operate on the liquid crystal material to expose display areas. Pleichroic dyes are added to the liquid crystal to cause the liquid crystal material to act as a shutter over the printed areas. The technology from this and related patents was licensed to the Taliq Corporation of Sunnyvale, Calif. Currently, Taliq products form electrical interconnection by offsetting the two sheets and contacting trace conductors from each of the two sheets.
Image displays can provide color images if a color filter array is formed over the pixels of the display. In U.S. Pat. No. 5,462,822, three color layers are formed on a transparent substrate. In this patent, a transparent electrode layer is formed over the color filter. The filter plate is aligned onto a liquid crystal layer. The plate is glass and has silver halide, color-forming layers. A transparent electrode material is sputtered at high temperature over the color filter array. In practice, the presence of the transparent electrode material causes ionic migration of the dyes in the dye layers. It would be advantageous to separate the electrically conductive layer from the dye layers.
The prior art requires multiple, separate layers on multiple plates to build up the display. The electrical traces and transparent conductive layers are typically formed through repeated vacuum deposition of materials on the substrate. These processes are expensive and require long processing times on capital intensive equipment Because most display structures are formed of glass, two sheets are used and are offset to permit connection to two separate and exposed sets of traces that are disposed on separate sheets. It would advantageous to lower the cost of flat panel displays. Additionally, current structures are not amenable to the creation of low-cost large flat panel displays. It would be advantageous to be able to form low-cost, large flat-panel displays.
A simple means is required to form electrical interconnection with both layers of traces. Prior art teaches isolating each layer on separate sides of the display, and connecting the traces to drive electronics using solder connections, wire bonds or pressure contact. Such connections do require that both sets of traces be exposed on a surface for the connection process. The uniform, multilayer structure prevents connection to the inner conductive layer.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to permit light formable display areas on a display sheet having multiple uniform coatings.
This object is achieved by a display for presenting selected images to a viewer, comprising:
(a) a transparent substrate;
(b) a transparent, electrically conductive coating formed over the transparent substrate;
(c) a light modulating layer formed over the transparent, electrically conductive layer,
(d) a photosensitive layer formed over the light modulating layer which is adapted to be exposed and developed to provide viewable and conductive images;
(e) the light modulating layer being effective in two conditions, in a first condition to prevent the viewing of the viewable and conductive images and in a second condition to permit the viewing of the viewable and conductive images; and
(f) electrical conduction means connected to the viewable and conductive images and the transparent, electrically conductive coating for applying a field to selected ones of such viewable and conductive images to cause the light modulating layer to change from the first condition to the second condition so as to present such viewable and conductive images for viewing to the viewer.
ADVANTAGES
The disclosed structure has the advantage of providing a reflective display using light sensitive, conductor forming coatings over a liquid crystal, light modulating layer. The liquid crystal material and light sensitive conductor forming material is inexpensive when coated simultaneously using current photographic coating technology. The sheet can be formed using inexpensive, fast photographic means to expose and develop a display. A single large volume of sheet material can be coated and formed into different types of displays by exposing the light sensitive material to different patterns.
REFERENCES:
patent: 4435047 (1984-03-01), Fergason
patent: 4670097 (1987-06-01), Abdalla et al.
patent: 5049480 (1991-09-01), Nebe et al.
patent: 5384618 (1995-01-01), Schurman et al.
patent: 5396304 (1995-03-01), Salerno et al.
patent: 5444557 (1995-08-01), Spitzer et al.
patent: 546
Anyaso Uchendu O.
Eastman Kodak Company
Owens Raymond L.
Saras Steven
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