Liquid crystal display matrix array employing ovonic threshold switching devices to isolate individual pixels

• US 5,757,446 A
• Filed: 10/30/1995
• Issued: 05/26/1998
• Est. Priority Date: 10/14/1994
• Status: Expired due to Fees

• Current Assignee: Ovonyx Incorporated (Micron Technology, Inc.)
• Original Assignee: Energy Conversion Devices
• Inventors: Czubatyj, Wolodymyr, Ovshinsky, Stanford R., Wicker, Guy C., Young, Rosa
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MALINOWSKI, WALTER J
• Application Number:
  US08/549,893
• Time in Patent Office: 939 Days
• Field of Search: 359/58, 359/60, 501/40, 349/49, 349/51, 349/52
• US Class Current: 349/49
• CPC Class Codes: C03C 3/321 Chalcogenide glasses, e.g. containing S, Se, Te
• CPC Class Codes: G02F 1/1365 in which the switching element is a two-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 3/367 with a nonlinear element in series with the liquid crystal cell, e.g. a diode, or M.I.M. element
• CPC Class Codes: H10N 70/20 Multistable switching devices, e.g. memristors
• CPC Class Codes: H10N 70/882 Compounds of sulfur, selenium or tellurium, e.g. chalcogenides
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

An acute matrix liquid crystal display panel including 1) a plurality of liquid crystal display elements distributed in a matrix of rows and columns; 2) means for supplying video signals and display element selection signals, including row and column conductors; and 3) a plurality of paired Ovonic threshold switches and resistive elements each serially coupled between the corresponding row or column conductor and the liquid crystal display element, the Ovonic threshold switches acting as display element selection devices and current isolation devices in which the Ovonic threshold switches having an off state resistance of at least 1×10⁹ ohms.

Claims

1. An active matrix liquid crystal display panel including:

a plurality of liquid crystal display elements distributed in a matrix of rows and columns;

means for supplying video signals and display element selection signals, including row and column conductors; and

a plurality of paired Ovonic threshold switches and resistive elements each serially coupled between the corresponding row or column conductor and the liquid crystal display element, said Ovonic threshold switches acting as display element selection devices and current isolation devices;

said Ovonic threshold switches having an off-state resistance of at least 1×

10⁹ ohms.

2. The active matrix liquid display panel of claim 1, where said Ovonic threshold switches have an off-state resistance of at least 1×

10¹⁰ ohms.

3. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have an off-state resistance of at least 1×

10¹¹ ohms.

4. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have an off-state resistance of at least 1×

10¹² ohms.

5. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches include a body of chalcogenide threshold switching material disposed between two electrical contacts.

6. The active matrix liquid crystal display panel of claim 5, wherein said body of chalcogenide threshold switching material is a thin-film.

7. The active matrix liquid crystal display panel of claim 5, wherein said chalcogenide threshold switching material is an arsenic-tellurium based material.

8. The active matrix liquid crystal display panel of claim 7, wherein said chalcogenide threshold switching material additionally includes one or more elements selected from the group consisting of germanium, silicon, phosphorus, sulfur and selenium.

9. The active matrix liquid crystal display panel of claim 8, wherein said chalcogenide threshold switching material is As₄₁ Te₃₉ Ge₅ Si₁₄ P₁, wherein the subscripts are the atomic ratios of the respective elements.

10. The active matrix liquid crystal display panel of claim 8, wherein said chalcogenide threshold switching material is AS₃₈ Te₃₇ Ge₅ Si₁₄ P₁ Se₅, wherein the subscripts are the atomic ratios of the respective elements.

11. The active matrix liquid crystal display panel of claim 8, wherein said chalcogenide threshold switching material is As₃₆ Te₃₄ Ge₅ Si₁₄ P₁ Se₁₀, wherein the subscripts are the atomic ratios of the respective elements.

12. The active matrix liquid crystal display panel of claim 8, wherein said chalcogenide threshold switching material is As₃₈ Te₃₇ Ge₅ Si₁₉ P₁, wherein the subscripts are the atomic ratios of the respective elements.

13. The active matrix liquid crystal display panel of claim 8, wherein said chalcogenide threshold switching material is As₃₆ Te₃₄ Ge₅ Si₂₄ P₁, wherein the subscripts are the atomic ratios of the respective elements.

14. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches are deposited onto glass substrates.

15. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have an on current of about 1×

10^-3 A or greater.

16. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have a threshold voltage as low as about 3 volts.

17. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have a switching time of less than about 1000 nanoseconds.

18. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have a cross sectional area that allows for an aperture ratio of at least about 0.6 or greater.

19. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches are not sensitive to light.

20. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches are deposited at temperatures below about 300°

C. or less.

21. The active matrix liquid crystal display panel of claim 1, wherein said Ovonic threshold switches have a hold current of about 0.1 microamps, said resistive elements have a resistance of about 10⁷ ohms, and said liquid crystal display element has a capacitance of about 0.2 pF.

22. An active matrix liquid crystal display panel including:

a plurality of liquid crystal display elements distributed in a matrix of rows and columns;

means for supplying video signals and display element selection signals, including row and column conductors; and

a plurality of paired Ovonic threshold switches and resistive elements each serially coupled between the corresponding row or column conductor and the liquid crystal display element, said Ovonic threshold switches active as display selection devices and current isolation devices;

wherein said Ovonic threshold switches have an off-state resistance of at least 1×

10⁹ ohms, and

wherein said Ovonic threshold switches include a body of chalcogenide threshold switching material disposed between two electrical contacts where said chalcogenide threshold switching material is selected from the group consisting of As₄₁ Te₃₉ Ge₅ Si₁₄ P₁, As₃₈ Te₃₇ Ge₅ Si₁₄ P₁ Se₅, As₃₆ Te₃₄ Ge₅ Si₁₄ P₁ Se₁₀, As₃₈ Te₃₇ Ge₅ Si₁₉ P₁, and As₃₆ Te₃₄ Ge₅ Si₂₄ P₁, where the subscripts are the atomic ratios of the respective elements. Please add the following claims.

23. An active matrix liquid crystal display panel including:

a plurality of liquid crystal display elements distributed in a matrix of rows and columns;

means for supplying video signals and display element selection signals, including row and column conductors; and

a plurality of paired Ovonic threshold switches and resistive elements each serially coupled between the corresponding row or column conductor and the liquid crystal display element, said Ovonic threshold switches acting as display element selection devices and current isolation devices;

wherein said Ovonic threshold switches have an off-state resistance of at least 1×

10⁹ ohms, and

wherein said Ovonic threshold switches include a body of chalcogenide threshold switching material disposed between two electrical contacts.

24. The active matrix liquid crystal display panel of claim 23, wherein said body of chalcogenide switching material is a thin-film.

25. The active matrix liquid crystal display panel of claim 23, wherein said chalcogenide threshold switching material is an arsenic-tellurium based material.

26. The active matrix liquid crystal display panel of claim 25, wherein said chalcogenide threshold switching material additionally includes one or more elements selected from the group consisting of germanium, silicon, phosphorus, sulfur, and selenium.