Tessellated electroluminescent display having a multilayer ceramic substrate

• US 5,644,327 A
• Filed: 06/07/1995
• Issued: 07/01/1997
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Transpacific Infinity LLC
• Original Assignee: David Sarnoff Research Center, Inc.
• Inventors: Cherukuri, Satyam C., Salsman, Kenneth E., Prabhu, Ashok Narayan, Yocom, P. Niel, Onyskevych, Lubomyr Stephen
• Primary Examiner(s): Brier, Jeffery
• Application Number:
  US08/472,540
• Time in Patent Office: 755 Days
• Field of Search: 345/1, 345/76, 345/80, 345/903, 313/498, 313/503, 313/505, 315/169.3
• US Class Current: 345/80
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: H01J 2201/304 Field emission cathodes
• CPC Class Codes: H01J 2329/90 Leading-in arrangements; seals therefor
• CPC Class Codes: H01J 2329/92 Means forming part of the display panel for the purpose of providing electrical connection to it
• CPC Class Codes: H01J 31/127 using large area or array sources, i.e. essentially a source for each pixel group
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16235 the bump connector connecting to a via metallisation of the item
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H05K 1/0306 Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 1/16 incorporating printed electric components, e.g. printed resistor, capacitor, inductor
• CPC Class Codes: H05K 3/4629 laminating inorganic sheets comprising printed circuits, e.g. green ceramic sheets
• CPC Class Codes: H05K 3/4641 having integrally laminated metal sheets or special power cores

Abstract

An electroluminescent display formed on a ceramic substrate having a front ceramic surface and a back ceramic surface. The ceramic substrate includes a metal core that provides structural support, electrical ground, and heat dissipation. Electroluminescent cells are mounted on the front ceramic surface and driver circuits for driving the of electroluminescent cells are mounted on the back ceramic surface. The driver circuits are positioned directly behind said electroluminescent cells. Connectors extend through said ceramic substrate and the electroluminescent cells to different driver circuits. By positioning the driver circuits close to the EL cells, the drive lines from the drivers to the EL cells are short which allows for high refresh rates and low resistance losses. Each of the driver circuits can drive one electroluminescent cell or a group of electroluminescent cells. EL display cells coupled to a cermet electrode can also be driven by a field emission device or a low power electron beam.

Claims

1. An electroluminescent display comprising:

a ceramic substrate having a first planar surface;

a plurality of electroluminescent cells mounted on said first planar surface;

a plurality of driver circuits for driving the plurality of electroluminescent cells; and

a plurality of connectors extending through said ceramic substrate which couple the plurality of electroluminescent cells to the plurality of driver circuits, each of the plurality of connectors comprising an insulating wall defining an insulated via through said ceramic substrate, said via being filled with a conductive material.

2. The electroluminescent display of claim 1 wherein:

said ceramic substrate has a second planar surface parallel to the first surface, and

the plurality of driver circuits are mounted on said second planar surface of said ceramic substrate.

3. The electroluminescent display of claim 1 wherein each of said plurality of driver circuits drives a respectively different one of said electroluminescent cells.

4. The electroluminescent display of claim 1 wherein each of said plurality of driver circuits drives a respectively different group of electroluminescent cells.

6. The electroluminescent display of claim 2 wherein the plurality of electroluminescent cells and the plurality of driver circuits are encapsulated.

14. The electroluminescent display of claim 1 wherein the electroluminescent cells are arranged in rows and columns and a single column of electroluminescent cells is driven by a plurality of driver circuits.

5. An electroluminescent display comprising:

a ceramic substrate having a first planar surface, wherein the ceramic substrate comprises a metal core layer positioned between two ceramic layers;

a plurality of electroluminescent cells mounted on said first planar surface;

a plurality of driver circuits for driving the plurality of electroluminescent cells; and

a plurality of connectors extending through said ceramic substrate which couple the plurality of electroluminescent cells to the plurality of driver circuits.

11. The electroluminescent display of claim 5 wherein the metal core layer includes feedthroughs for providing signal distribution from said plurality of driver circuits to said plurality of electroluminescent cells.

12. The electroluminescent display of claim 5 wherein the metal core layer provides a means for heat dissipation.

15. The electroluminescent display of claim 5, wherein connectors include conductive material that is insulated from said metal core layer.

7. An electroluminescent display comprising:

a ceramic substrate having a first planar surface and a second planar surface parallel to the first surface, wherein the ceramic substrate includes an edge surface perpendicular to said first and second planar surfaces, said edge surface including connectors for electrically connecting the ceramic substrate with a second ceramic substrate;

a plurality of electroluminescent cells mounted on said first planar surface;

a plurality of driver circuits for driving the plurality of electroluminescent cells; and

a plurality of connectors extending through said ceramic substrate which couple the plurality of electroluminescent cells to the plurality of driver circuits.

8. The electroluminescent display of claim 7 wherein the ceramic substrate is electrically connected to said second ceramic substrate by abutting the edge surface of said ceramic substrate against an edge surface of said second ceramic substrate, each of said edge surfaces including electrical connectors.

9. An electroluminescent display comprising:

a ceramic substrate having a first planar surface;

a plurality of electroluminescent cells mounted on said first planar surface;

a plurality of driver circuits for driving the plurality of electroluminescent cells; and

a plurality of connectors extending through said ceramic substrate which couple the plurality of electroluminescent cells to the plurality of driver circuits,

wherein ones of said plurality of electroluminescent cells are placed adjacent to the edge of said first planar surface and wherein the spacing between the edge of said first planar surface and said ones of said electroluminescent cells is less than one half of the spacing between adjacent electroluminescent cells placed at an interior portion of said first planar surface.

10. The electroluminescent display of claim 9 wherein the ceramic substrate includes:

a second planar surface parallel to the first planar surface and

an edge surface perpendicular to said first and second planar surfaces and a large area display is formed by abutting the edge surfaces of a plurality of ceramic substrates.

13. An electroluminescent display comprising:

a ceramic substrate having a first planar surface, wherein the first planar surface of said ceramic substrate is polished and includes a glass layer deposited on the polished first planar surface of the ceramic substrate;

a plurality of electroluminescent cells mounted on said first planar surface;

a plurality of driver circuits for driving the plurality of electroluminescent cells; and

a plurality of connectors extending through said ceramic substrate which couple the plurality of electroluminescent cells to the plurality of driver circuits.