Active matrix electroluminescent cell design

• US 5,463,279 A
• Filed: 08/19/1994
• Issued: 10/31/1995
• Est. Priority Date: 08/19/1994
• Status: Expired due to Term

• Current Assignee: Planar Systems Incorporated (Leyard Optoelectronic Co., Ltd.)
• Original Assignee: Planar Systems Incorporated (Leyard Optoelectronic Co., Ltd.)
• Inventors: Khormaei, Iranpour
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): VU, DAVID HUNG
• Application Number:
  US08/293,144
• Time in Patent Office: 438 Days
• Field of Search: 315/169.3, 315/56, 315/76, 315/160, 315/169.1, 315/51, 340/825.81, 340/825.91, 313/498, 313/506, 313/509
• US Class Current: 315/169.3
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces

Abstract

An electroluminescent device comprises a plurality of layers including at least a transparent electrode layer, a circuit layer, and typically three layers including an electroluminescent layer sandwiched between front and rear dielectric layers, all three layers thereof disposed between the circuit layer and the transparent electrode layer. The circuit layer further comprises a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device. The charge storage device has a terminal connected to a first ground layer. A second gating device comprises a transistor operating in a breakdown region. The transistor has a gate coupled to the input to the charge storage device and has a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode. The transparent electrodes are carrying an electrical signal such that upon activation of the second gating device an electric field is generated between the transparent electrode layer and the pixel electrode so as to cause the electroluminescent layer to emit light.

Claims

1. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer said at least two layers thereof disposed between said circuit layer and said transparent electrode layer, the improvement comprising:

(a) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a first ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode; and

(b) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

2. The device of claim 1 further comprising, said circuit layer deposited on a rearwardly disposed substrate.

3. The device of claim 2 wherein said first ground layer and said second ground layer are said substrate.

4. The device of claim 1 further comprising at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said electroluminescent layer and said circuit layer.

5. The device of claim 2 wherein said second ground layer is sandwiched between front and rear insulator layers, all three layers thereof being disposed between said dielectric layer and said circuit layer.

6. The device of claim 2 wherein said first ground layer is sandwiched between front and rear insulator layers, all three layers disposed between said dielectric layer and said circuit layer.

7. The device of claim 1 wherein said pixel electrode is on the order of 22 μ

m×

22 μ

m in size.

8. The device of claim 1 wherein said first gating device comprises a transistor that is on the order of 5 μ

m×

15 μ

m in size.

9. An electroluminescent device comprising:

(a) a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers disposed between said circuit layer and said transparent electrode layer;

(b) said circuit layer deposited on a rearwardly disposed substrate; and

(c) said circuit layer further comprising;

(i) a first gating device electrically connecting a data line to a charge storage device by activation of a select line;

(ii) said charge storage device electrically connected between a first ground layer and a second gating device;

(iii) said second gating device electrically connecting a pixel electrode to a second ground layer by activation of said charge storage device;

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device, an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

10. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least three layers including an electroluminescent layer sandwiched between front and rear dielectric layers, all three layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a first ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode;

(c) said first ground layer and said second ground layer are said substrate; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

11. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least three layers including an electroluminescent layer sandwiched between front and rear dielectric layers, all three layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a first ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said rear dielectric layer and said circuit layer; and

(c) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

12. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least three layers including an electroluminescent layer sandwiched between front and rear dielectric layers, all three layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said rear dielectric layer and said circuit layer;

(c) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to said substrate;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to said ground plane and a second terminal coupled to a pixel electrode; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

13. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least three layers including an electroluminescent layer sandwiched between front and rear dielectric layers, all three layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said rear dielectric layer and said circuit layer;

(c) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a said ground plane;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to said substrate and a second terminal coupled to a pixel electrode; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

14. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a first ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode;

(c) said first ground layer and said second ground layer are said substrate; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

15. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a first ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to a second ground layer and a second terminal coupled to a pixel electrode;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said dielectric layer and said circuit layer; and

(c) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

16. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said dielectric layer and said circuit layer;

(c) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to said substrate;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to said ground plane and a second terminal coupled to a pixel electrode; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

17. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer deposited on a rearwardly disposed substrate;

(b) at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said dielectric layer and said circuit layer;

(c) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a said ground plane;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to said substrate and a second terminal coupled to a pixel electrode; and

(d) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

18. In an electroluminescent device comprising a plurality of layers including at least a transparent electrode layer, a circuit layer, and at least two layers including an electroluminescent layer and a dielectric layer, said at least two layers thereof disposed between said circuit layer and said transparent electrode layer the improvement comprising:

(a) said circuit layer further including;

(i) a first gating device coupled to a data line and a select line and having an output coupled to an input of a charge storage device, said charge storage device having a terminal connected to a ground layer;

(ii) a second gating device comprising a transistor operating in a breakdown region, said transistor having a gate coupled to said input to said charge storage device and having a first terminal coupled to said ground layer and a second terminal coupled to a pixel electrode; and

(b) said transparent electrodes carrying an electrical signal such that upon activation of said second gating device an electric field is generated between said transparent electrode layer and said pixel electrode so as to cause said electroluminescent layer to emit light.

19. The device of claim 18 further comprising, said circuit layer deposited on a rearwardly disposed substrate.

20. The device of claim 19 wherein said ground layer is said substrate.

21. The device of claim 18 further comprising at least three additional layers, including a ground plane sandwiched between front and rear insulator layers, all three layers thereof disposed between said dielectric layer and said circuit layer.

22. The device of claim 18 further comprising said ground layer sandwiched between front and rear insulator layers, all three layers thereof disposed between said dielectric layer and said circuit layer.

23. The device of claim 18 wherein said pixel electrode is on the order of 22 μ

m×

22 μ

m in size.

24. The device of claim 18 wherein said first gating device comprises a transistor that is on the order of 5 μ

m×

15 μ

m in size.