Electronic fluorescent display system with simplified multiple electrode structure and its processing

• US 5,859,508 A
• Filed: 04/25/1997
• Issued: 01/12/1999
• Est. Priority Date: 02/25/1991
• Status: Expired due to Fees

• Current Assignee: PixTech, Inc.
• Original Assignee: PixTech, Inc.
• Inventors: Xu, Yi, Ge, Shichao, Huang, Xi, Leung, Charles S.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US08/846,029
• Time in Patent Office: 627 Days
• Field of Search: 315/866, 313/422, 313/292, 313/243, 313/267-8, 313/257
• US Class Current: 315/366
• CPC Class Codes: H01J 2329/863 characterised by the form or structure
• CPC Class Codes: H01J 2329/864 characterised by the material
• CPC Class Codes: H01J 29/028 Mounting or supporting arrangements for flat panel cathode ray tubes, e.g. spacers particularly relating to electrodes
• CPC Class Codes: H01J 29/467 Control electrodes for flat display tubes, e.g. of the type covered by group H01J31/123
• CPC Class Codes: H01J 31/126 using line sources

Abstract

An improved cathodoluminescent device with a one piece spacer structure which is rigidly connected to two sets of grid electrodes. The spacer structure defines holes therein that spatially match pixel dots on an anode on a face plate. One set of grid electrodes comprises layers of electrically conductive material on surfaces within at least some of the holes of the spacer structure. The two sets of grid electrodes and different spacer layers may be attached together to form a one piece spacer structure integral with the two sets of grid electrodes. The display device is then simply assembled by matching each of the holes of the spacer structure with a pixel dot on the face plate, and attaching the structure to the face plate and a back plate.

Claims

1. A cathodoluminescent visual display device having a plurality of pixel dots for displaying images when said device is viewed in a viewing direction, comprising:

a housing defining a chamber therein, said housing having a face plate, and a back plate;

an anode on or near said face plate;

luminescent means that emits light in response to electrons, and that is on or adjacent to the anode;

at least one cathode in the chamber between the face and back plates;

a spacer structure defining holes therein for passage of electrons, said spacer structure comprising a plurality of spacer layers attached to form a unitary spacer structure;

at least a first and a second set of elongated grid electrodes between the anode and cathode and separated by at least one of said spacer layers, the electrodes in one of the first and second sets overlapping the luminescent means and grid electrodes in the other set at points when viewed in the viewing direction, wherein the overlapping points define pixel dots;

wherein one of the first and second sets of grid electrodes comprises a layer of an electrically conductive material on surfaces within the holes of the spacer structure;

means for causing the cathode to emit electrons; and

means for applying electrical potentials to the anode, cathode and the two or more sets of grid electrodes, causing the electrons emitted by the cathode to travel to the luminescent means at the pixel dots on or adjacent to the anode for displaying images, said electrical potentials applying means applying such potentials to the layer on the surfaces within the holes that electrons passing there through are focused onto selected pixel dots, wherein each of the holes of the spacer structure contains only one integral layer of electrically conductive material.

2. The device of claim 1, said spacer structure comprising at least a first and a second individual layer attached to form the unitary spacer structure;

said first layer having support portions and separation portions, said second layer having support portions corresponding to and attached to the support portions of the first layer to form the support wall between any two adjacent holes of the spacer structure.

3. The device of claim 2, said first layer being closer to the back plate than the face plate, and said second layer being closer to the face plate than the back plate, said separation portions of the first layer forming separation walls within each of said holes to divide each of said holes into smaller holes, said separation walls being thinner than the support walls, thereby reducing crosstalk.

4. The device of claim 2, said first layer comprising a metallic substrate and a dielectric material coating, and said second layer comprising a material of electrical resistance in the range of about 10⁸ to 10¹⁴ Ohms.

5. The device of claim 4, wherein said dielectric material coating comprises a glass powder mixture, polyimide or siloxane polymers.

6. The device of claim 4, wherein the total thickness of said first and second layers together is in the range of about 1 to 35 mm.

7. The device of claim 2, wherein said second set of grid electrodes comprises a thin film electrically conducting material on the support and separation portions of the first layer, said spacer structure further comprising separation spacers between and attached to the first set of grid electrodes and the first layer, said separation spacers comprising glass beads and a high temperature adhesive.

8. The device of claim 2, wherein said one of the first and second sets of grid electrodes comprises a thin film electrically conducting material on the support and separation portions of the first layer.

9. The device of claim 1, said spacer structure having a thickness in the range of 1 to 40 mm, wherein the distance between the at least one cathode and the anode is in the range of 4 to 40 mm.

10. The device of claim 9, said electrical potential applying means applying potentials so that the potential of the anode is in the range of 1 kV to 8 kV, the potential of the at least one cathode is less than about 100 V and the potentials of the two sets of grid electrodes are less than 200 V.

11. The device of claim 1, further comprising electron shaping electrodes on or adjacent to the back plate to control the emitted electrons from the cathode to be evenly distributed so as to improve brightness uniformity.

12. The device of claim 11, said device comprising a plurality of cathodes in the form of filaments in a spatial arrangement, wherein said electron shaping electrodes comprise layers of an electrically conducting material in a design pattern corresponding to the spatial arrangement of the filaments.

13. The device of claim 1, wherein said one integral layer of electrically conductive material in each of said the holes of the spacer structure extends over a substantial portion of the surface of such hole so that the electrical potential within such hole is substantially that applied by the applying means to the layer of electrically conductive material within such hole.

14. The device of claim 1, further comprising means for evacuating said chamber.

15. The device of claim 1, said at least one cathode comprising at least one filament, said device further comprising means for heating the at least one filament to emit electrons.