Display panel

• US 5,557,295 A
• Filed: 11/06/1992
• Issued: 09/17/1996
• Est. Priority Date: 11/28/1991
• Status: Expired due to Fees

• Current Assignee: Nippon Sieko Kabushiki Kaisha
• Original Assignee: Nippon Seiko Kabushiki Kaisha
• Inventors: Zhang, Laiying, Miyashita, Sadamasa
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): Mengistu, Amare
• Application Number:
  US07/972,681
• Time in Patent Office: 1,411 Days
• Field of Search: 340/784, 340/781, 340/815.15, 345/36, 345/43, 313/509, 428/31, 359/48, 359/54, 359/68, 359/89, 359/98
• US Class Current: 345/36
• CPC Class Codes: B60K 35/00 Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
• CPC Class Codes: B60Q 3/14 lighting through the surface to be illuminated
• CPC Class Codes: B60Q 3/16 Circuits; Control arrangements
• CPC Class Codes: B60Q 3/85 for manual control of the light, e.g. of colour, orientation or intensity
• CPC Class Codes: G01D 11/28 Structurally-combined illuminating devices
• CPC Class Codes: G09F 13/22 electroluminescent electroluminescent light sources per se H05B33/00
• CPC Class Codes: G09F 2013/222 with LEDs
• CPC Class Codes: G09F 2013/227 Electroluminescent displays for vehicles

Abstract

A display panel integrated with EL can be obtained by printing EL at the back of a light permeable substrate, and covering the front surface of the substrate and the rearface of EL with a moisture proof film for insulating and protecting the EL from the surrounding atmosphere. Alternatively, the film may cover the substrate and EL entirely. An indication mark is printed at the surface of the moisture proof film or the light permeable substrate. The light permeable front electrode, the light emission layer and the back electrode are successively printed to the rearface of the light permeable substrate. If the indication mark is printed on the surface of the substrate, the attenuation of decay of the light emission from the emission layer can be suppressed and the brightness of the display mark improved by not forming the insulation layer at the back of the substrate. Alternatively, by forming the insulation layer at the back of the substrate, the entire thickness and the weight of the display panel can be decreased and the production step simplified.

Claims

1. A display panel comprising:

a light permeable substrate having an indication mark on the surface thereof; and

a light permeable front electrode, a light emission layer, a back electrode and an insulating layer successively formed at the back of the light permeable substrate;

wherein (i) the light permeable front electrode, the light emission layer, the back electrode and the insulating layer are formed by screen printing and (ii) the insulating layer insulates said front electrode, said light emission layer and said back electrode from the surrounding atmosphere.

2. A display panel according to claim 1, wherein the light permeable front electrode is in a shape corresponding to an indication mark.

3. A display panel according to claim 2, wherein said light emission layer has substantially the same shape as the light permeable front electrode.

4. A display panel according to claim 1, wherein the insulating layer is formed by applying an insulating material in liquid form.

5. A display panel according to claim 1, wherein the insulating layer is formed so as to cover surfaces of the light permeable front electrode, the light emission layer, and the back electrode and a back surface of the back electrode.

6. A display panel according to claim 1, wherein the indication mark is formed by screen printing.

7. A display panel according to claim 1, wherein the insulating layer is moisture proof.

8. A display panel comprising:

a light permeable substrate having an indication mark on the surface thereof; and

a light permeable front electrode, a light emission layer, a back electrode and an insulating layer successively formed at the back of the light permeable substrate;

wherein;

the light permeable front electrode, the light emission layer, the back electrode and the insulating layer are formed by screen printing;

the back of the light permeable substrate has a first surface portion and a second surface portion, and the light permeable front electrode is formed to be in contact with only the first surface portion; and

the insulating layer insulates said front electrode, said light emission layer and said back electrode from the surrounding atmosphere and is formed so as (i) to entirely cover side surfaces of the light permeable front electrode, the light emission layer, and the back electrode and a back surface of the back electrode, and (ii) to be in contact with only the second surface portion of the back of the light permeable substrate.

9. A display panel according to claim 8, wherein the light permeable front electrode is in a shape corresponding to an indication mark.

10. A display panel according to claim 9, wherein said light emission layer has substantially the same shape as the light permeable front electrode.

11. A display panel according to claim 8, wherein the insulating layer is formed by applying an insulating material in liquid form.

12. A display panel according to claim 8, wherein the indication mark is formed by screen printing.

13. A display panel according to claim 8, wherein the insulating layer is moisture proof.

14. A display panel comprising:

a light permeable substrate having an indication mark on the surface thereof; and

a light permeable front electrode, a light emission layer, a back electrode and an insulating layer formed at the back of the light permeable substrate;

wherein the back of the light permeable substrate has a first surface portion and a second surface portion, and the light permeable front electrode is formed to be in contact with only the first surface portion and the insulating layer is formed to be in contact with only the second surface portion of the back of the light permeable substrate.

15. A display panel according to claim 14, wherein said light permeable front electrode and said light emission layer are substantially in a shape corresponding to the indication mark.

16. A display panel according to claim 14, wherein the insulating layer is formed by applying an insulating material in liquid form.

17. A display panel according to claim 14, wherein the indication mark is formed by screen printing.

18. A display panel according to claim 14, wherein the insulating layer is moisture proof.

19. A display panel according to claim 14, wherein the light permeable front electrode, the light emission layer, the back electrode and the insulating layer are successively formed by screen printing.

20. A display panel according to claim 14, wherein the insulating layer is formed to entirely cover side surfaces of the light permeable front electrode, the light emission layer, and the back electrode and a back surface of the back electrode and insulates said front electrode, said light emission layer and said back electrode from the surrounding atmosphere.