Display and method for driving the display

• US 8,477,105 B2
• Filed: 07/16/2009
• Issued: 07/02/2013
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: Yanase, Jiro, Kitagishi, Yoichi, Haga, Hiroshi
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): Hegarty, Kelly B
• Application Number:
  US12/504,218
• Publication Number:
  US 20100013791A1
• Time in Patent Office: 1,447 Days
• Field of Search: 345/173, 345/174, 345/104, 178 1805- 1806, 178/18.01, 178/18.03
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A display comprising: an electro-optical material arranged between first and second planes facing each other; a first substrate arranged on the first plane and including a conductor that affords an electrical signal to the electro-optical material; a first electrically conductive film arranged on the second plane to afford an electrical signal to the electro-optical material; a second electrically conductive film arranged outside an area sandwiched between the first and second planes; and a current detection circuit that detects the current on the second electrically conductive film. The display further comprises a control circuit that, during a time period the current is detected by the current detection circuit, applies substantially the same voltage as that applied to the second electrically conductive film to one of the conductor and the first electrically conductive film, which is arranged more proximate to the second electrically conductive film, and sets the other in a floating state, or applies substantially the same voltage as that applied to the second electrically conductive film to both the conductor and the first electrically conductive film.

Claims

1. A display comprising:

an electro-optical material arranged between first and second planes facing each other;

a first substrate arranged on said first plane and including a thin film transistor and a conductor that affords an electrical signal to said electro-optical material;

a first electrically conductive film arranged on said second plane to afford an electrical signal to said electro-optical material;

a second electrically conductive film arranged outside an area sandwiched between said first and second planes;

a current detection circuit that detects a current on said second electrically conductive film;

a control circuit that, during a time period the current is detected by said current detection circuit, applies substantially the same voltage as that applied to said second electrically conductive film to one of said conductor and said first electrically conductive film, which is arranged more proximate to said second electrically conductive film, and sets the other in a floating state, or applies substantially the same voltage as that applied to said second electrically conductive film to both said conductor and said first electrically conductive film; and

a detecting unit that detects, based on the current detected by said current detection circuit, whether or not touch has been made by a finger or a pointer and where the touch has been made.

2. The display according to claim 1, wherein said electro-optical material comprises anyone selected from the group consisting of liquid crystal, an electrophoretic material, charged particles, an electrochromic material, an EL material, a gas, a semiconductor and a phosphorescent material.

3. The display according to claim 1 further comprising:

an ac voltage source that applies ac voltage to said second electrically conductive film;

said current detection circuit detecting the current between said ac voltage source and said second electrically conductive film.

4. The display according to claim 3, wherein

said electro-optical material is composed mainly of liquid crystal;

said first electrically conductive film is transparent;

said second electrically conductive film is transparent and arranged on the same side of an area delimited by said first and second planes as said first electrically conductive film;

said display further comprising a second substrate sandwiched between said first and second electrically conductive films; and

wherein

during the time period said current detection circuit detects the current, said control circuit sets a part of said conductor extending from inside to outside of a viewing area to a floating state and applies substantially the same voltage as that applied to said second electrically conductive film to said first electrically conductive film, or applies substantially the same voltage as that applied to said second electrically conductive film to both said conductor part and said first electrically conductive film.

5. The display according to claim 4, wherein

said conductor includes a storage capacitance line extending from inside to outside of the viewing area;

and wherein

during the time period said current detection circuit detects the current, said control circuit sets said storage capacitance line to a floating state and applies substantially the same voltage as that applied to said second electrically conductive film to said first electrically conductive film, or applies substantially the same voltage as that applied to said second electrically conductive film to both said storage capacitance line and said first electrically conductive film.

6. The display according to claim 4, wherein

said conductor includes a scanning line extending from inside to outside said viewing area;

said scanning line being connected via a switch device to a scanning line driving circuit that drives said scanning line, or said scanning line driving circuit outputs three values of a high level, a low level and a high impedance, said scanning line driving circuit being directly connected to said scanning line.

7. The display according to claim 3, wherein

said electro-optical material is composed mainly of liquid crystal;

said first and second electrically conductive films are transparent;

said second electrically conductive film is arranged on the same side of an area delimited by said first and second planes as said first electrically conductive film;

said display further comprising;

a second substrate carrying thereon said first electrically conductive film; and

a third substrate carrying thereon said second electrically conductive film; and

wherein

during the time period said current detection circuit detects the current, said control circuit sets a part of said conductor extending from inside to outside of a viewing area to a floating state and applies substantially the same voltage as that applied to said second electrically conductive film to said first electrically conductive film, or applies substantially the same voltage as that applied to said second electrically conductive film to both said conductor part and said first electrically conductive film.

8. The display according to claim 3, wherein

said electro-optical material is composed mainly of liquid crystal;

said first electrically conductive film is opaque and has an opening;

said second electrically conductive film is transparent and arranged on the same side of an area sandwiched between said first and second planes as said first electrically conductive film;

said display further comprising;

a second substrate sandwiched between said first and second electrically conductive films; and

wherein

during the time period said current detection circuit detects the current, said control circuit sets a part of said conductor extending from inside to outside of a viewing area to a floating state and applies substantially the same voltage as that applied to said second electrically conductive film to said first electrically conductive film, or applies substantially the same voltage as that applied to said second electrically conductive film to both said conductor part and said first electrically conductive film.

9. An electronic apparatus comprising a display according to claim 1.

10. A display comprising:

an electro-optical material;

a conductor that affords an electrical signal to said electro-optical material;

a first electrically conductive film that affords an electrical signal to said electro-optical material;

a second electrically conductive film provided on a viewing area of said display;

a current detection circuit that detects a current on said second electrically conductive film;

a control circuit that, during a time period the current is detected by said current detection circuit, affords substantially the same voltage as that applied to said second electrically conductive film to one of said conductor and said first electrically conductive film, and sets the other in a floating state; and

a detecting unit that detects, based on the current detected by said current detection circuit, whether or not touch has been made by a finger or a pointer and where the touch has been made.

11. A driving method for a display comprising:

providing a display including;

an electro-optical material arranged between first and second planes facing each other;

a first substrate arranged on said first plane and including a thin film transistor and a conductor that affords an electrical signal to said electro-optical material;

a first electrically conductive film arranged on said second plane to afford an electrical signal to said electro-optical material; and

a second electrically conductive film arranged outside an area sandwiched between said first and second planes;

detecting the current on said second electrically conductive film by a current detection circuit;

applying, during a time period the current is detected by said current detection circuit, substantially the same voltage as that applied to said second electrically conductive film to one of said conductor and said first electrically conductive film which is arranged more proximate to said second electrically conductive film, and setting the other in a floating state, or applying substantially the same voltage as that applied to said second electrically conductive film to both said conductor and said first electrically conductive film; and

detecting, based on the current detected by said current detection circuit, whether or not a touch has been made by a finger or a pointer and where the touch has been made.

12. A display comprising:

an electro-optical material arranged between first and second planes facing each other;

a first substrate arranged on said first plane and including a thin film transistor and a conductor that affords an electrical signal to said electro-optical material;

a first electrically conductive film arranged on said second plane to afford an electrical signal to said electro-optical material;

a second electrically conductive film arranged outside an area sandwiched between said first and second planes;

a current detection circuit that detects a current on said second electrically conductive film;

a control circuit that, during a time period the current is detected by said current detection circuit, applies a voltage which is substantially the same in amplitude and phase as that applied to said second electrically conductive film, to one of said conductor and said first electrically conductive film while setting the other in a floating state, or that applies said voltage to said conductor and to said first electrically conductive film; and

a detecting unit that detects, based on the current detected by said current detection circuit, whether of not touch has been made by a finger or a pointer and where the touch has been made.

13. The display according to claim 12, further comprising:

an ac voltage source that applies ac voltage to said second electrically conductive film;

said current detection circuit detecting the current between said ac voltage source and said second electrically conductive film.

14. The display according to claim 13, wherein

said conductor is connected to a second voltage source via a switch device;

and wherein

said conductor is connected to said ac voltage source via a capacitor.

15. The display according to claim 13, wherein

said first electrically conductive film is connected to a third voltage source via a switch device;

and wherein

said first electrically conductive film is connected to said ac voltage source via a capacitor.

16. The display according to claim 13, further comprising:

a driving circuit that drives said conductor;

a power supply input terminal of said driving circuit; and

a power supply circuit that generates a voltage to be afforded to said power supply input terminal;

said power supply input terminal being connected to said power supply circuit via a switch device;

said power supply input terminal being connected to said ac voltage source via a capacitor.

17. The display according to claim 13, wherein

said electro-optical material is composed mainly of liquid crystal;

said first electrically conductive film is transparent;

said second electrically conductive film is transparent and arranged on the same side of an area delimited by said first and second planes as said first electrically conductive film; and

wherein

said display further comprises a second substrate sandwiched between said first and second electrically conductive films;

wherein

during the time period said current detection circuit detects the current, said control circuit sets a part of said conductor extending from inside to outside of a viewing area to a floating state and applies a voltage substantially the same in amplitude and phase as that applied to said second electrically conductive film to said first electrically conductive film, or applies said voltage to said part of said conductor extending from inside to outside of said viewing area and to said first electrically conductive film.

18. The display according to claim 17, wherein

said conductor includes a storage capacitance line extending from inside to outside of the viewing area;

and wherein

during the time period said current detection circuit detects the current, said control circuit sets said storage capacitance line to a floating state and applies a voltage which is substantially the same in amplitude and phase as that applied to said second electrically conductive film to said first electrically conductive film, or applies said voltage to said storage capacitance line and to said first electrically conductive film.

19. The display according to claim 17, wherein

said conductor includes a scanning line extending from inside to outside of said viewing area;

and wherein

said scanning line is connected via a switch device to a scanning line driving circuit that drives said scanning line, or said scanning line driving circuit outputs three values of a high level, a low level and a high impedance and is directly connected to said scanning line.

20. The display according to claim 19, further comprising:

a scanning line driving circuit that drives said scanning line;

a power supply input terminal of said scanning line driving circuit; and

a power supply circuit that generates a voltage to be afforded to said power supply input terminal;

said power supply input terminal being connected to said power supply circuit via a switch device;

said power supply input terminal of said scanning line driving circuit being connected to said ac voltage source via a capacitor.

21. An electronic apparatus including the display according to claim 12.