Sensing circuit, display device and electronic apparatus

• US 8,766,946 B2
• Filed: 04/21/2009
• Issued: 07/01/2014
• Est. Priority Date: 05/02/2008
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kanda, Eiji, Tsuchiya, Yasushi, Ozawa, Tokuro, Matsushima, Toshiharu
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): Nadkarni, Sarvesh J
• Application Number:
  US12/427,433
• Publication Number:
  US 20090273578A1
• Time in Patent Office: 1,897 Days
• Field of Search: 345156-184
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality

Abstract

A sensing circuit having a first substrate, a second substrate, a layer of dielectric material, a first electrode, a second electrode and an electrostatic capacitance detection unit is provided. The second substrate faces the first substrate. The dielectric material is held between the first substrate and the second substrate. The first electrode and the second electrode are arranged between the dielectric material and the first substrate. The electrostatic capacitance detection unit is configured to produce a detection signal having an amplitude according to a value of capacitance formed between the first electrode and the second electrode through the dielectric material.

Claims

1. A sensing circuit, comprising:

a first substrate;

a second substrate facing the first substrate;

a layer of dielectric material held between the first substrate and the second substrate;

a pixel including a first electrode and a second electrode, the first electrode being disposed between the dielectric material and the first substrate, the second electrode being disposed between the dielectric material and the first substrate,

wherein the first electrode is a common electrode of a pixel circuit and the second electrode is a pixel electrode of the pixel circuit;

a first sensing electrode, wherein the first sensing electrode and the common electrode of the pixel circuit are formed in a same first layer;

a second sensing electrode, wherein the second sensing electrode and the pixel electrode of the pixel circuit are formed in a same second layer; and

an electrostatic capacitance detection unit configured to produce a detection signal having an amplitude based on a capacitance formed between the first sensing electrode and the second sensing electrode through the dielectric material.

2. The sensing circuit of claim 1,

the first sensing electrode and the second electrode being formed on a same layer,

the first sensing electrode having at least two projections extending in one direction, and

the second sensing electrode having a projection extending toward a portion between the two projections of the first sensing electrode.

3. The sensing circuit of claim 1,

the first sensing electrode and the second sensing electrode being formed from different layers and arranged so as to face each other,

the first sensing electrode being arranged between the dielectric material and the second sensing electrode, and

a slit being formed in the first sensing electrode for passing an electric field generated between the first sensing electrode and the second sensing electrode.

4. The sensing circuit of claim 1,

the first sensing electrode and the second sensing electrode being formed from different layers,

the first sensing electrode being arranged between the dielectric material and the second sensing electrode,

at least one of the first sensing electrode and the second sensing electrode having at least two projections extending in one direction, and

an area of a portion of the first electrode overlapping the second sensing electrode being smaller than an area of a portion of the first sensing electrode other than the portion overlapping the second sensing electrode.

5. A display device including the sensing circuit of claim 1, further comprising:

a third electrode and a fourth electrode, the first sensing electrode and the third electrode being formed on a same layer, the second sensing electrode and the fourth electrode being formed on another same layer, and

a pixel circuit including the dielectric material that an electric field generated between the third electrode and the fourth electrode is applied to, the dielectric material being a substance having dielectric anisotropy.

6. A display device including the sensing circuit of claim 3, further comprising:

a third electrode and a fourth electrode, the first sensing electrode and the third electrode being formed on a same layer, the second sensing electrode and the fourth electrode being formed on another same layer, and

a pixel circuit including the dielectric material that an electric field generated between the third electrode and the fourth electrode is applied to, the dielectric material being a substance having dielectric anisotropy.

7. A display device including the sensing circuit of claim 4, further comprising:

a third electrode and a fourth electrode, the first sensing electrode and the third electrode being formed on a same layer, the second sensing electrode and the fourth electrode being formed on another same layer, and

a pixel circuit including the dielectric material that an electric field generated between the third electrode and the fourth electrode is applied to, the dielectric material being a substance having dielectric anisotropy.

8. The display device of claim 5, the dielectric material being a substance having dielectric anisotropy and optical anisotropy.

9. An electronic apparatus including the display device of claim 5.

10. The sensing circuit of claim 1, further comprising:

an orientation membrane covering at least the first electrode and the second electrode, and

the dielectric material being composed of liquid crystal molecules having long axes, the orientation membrane orienting the long axes in a direction parallel to the first substrate.

11. A sensing circuit, comprising:

a first substrate;

a second substrate;

a layer of dielectric material between the first substrate and the second substrate;

a pixel including a first electrode and a second electrode, the first electrode being disposed between the dielectric material and the first substrate, the second electrode being disposed between the dielectric material and the first substrate,

wherein the first electrode is a common electrode of a pixel circuit and the second electrode is a pixel electrode of the pixel circuit;

a first sensing electrode, wherein the first sensing electrode and the common electrode of the pixel circuit are formed in a same first layer and a second sensing electrode, wherein the second sensing electrode and the pixel electrode of the pixel circuit are formed in a same second layer, and

wherein a distance between the first sensing electrode and the second sensing electrode is kept constant such that a capacitance formed between the first sensing electrode and the second sensing electrode through the dielectric material corresponds to a target value that maximizes a detection sensitivity of the circuit.

12. The sensing circuit of claim 11, the distance between the first sensing electrode and the second sensing electrode being independent of a distance between the first substrate and the second substrate.

13. The sensing circuit of claim 11, the first sensing electrode and the second sensing electrode being formed on a same layer.

14. The sensing circuit of claim 11, the first sensing electrode and the second sensing electrode being formed on different layers.

15. A display device including the sensing circuit of claim 11, further comprising:

a third electrode and a fourth electrode, the first sensing electrode and the third electrode being formed on a same layer, the second sensing electrode and the fourth electrode being formed on another same layer, and

a pixel circuit including the dielectric material that an electric field generated between the third electrode and the fourth electrode is applied to, the dielectric material being a substance having dielectric anisotropy.

16. The sensing circuit of claim 11, further comprising:

an orientation membrane covering at least the first sensing electrode and the second sensing electrode, and

the dielectric material being composed of liquid crystal molecules having long axes, the orientation membrane orienting the long axes in a direction parallel to the first substrate.

17. The display device of claim 15, the dielectric material being a substance having dielectric anisotropy and optical anisotropy.

18. An electronic apparatus including the display device of claim 15.

19. A sensing circuit, comprising:

a first substrate;

a second substrate facing the first substrate;

a layer of dielectric material held between the first substrate and the second substrate;

a first electrode disposed between the dielectric material and the first substrate;

a second electrode disposed between the dielectric material and the first substrate,

wherein the first electrode is a common electrode of a pixel circuit and the second electrode is a pixel electrode of the pixel circuit;

a first sensing electrode, wherein the first sensing electrode and the common electrode of the pixel circuit are formed in a same first layer;

a second sensing electrode, wherein the second sensing electrode and the pixel electrode of the pixel circuit are formed in a same second layer; and

an electrostatic capacitance detection unit configured to produce a detection signal having an amplitude based upon a capacitance formed between the first sensing electrode and the second sensing electrode through the dielectric material.

20. A sensing circuit, comprising:

a first substrate;

a second substrate facing the first substrate;

a layer of dielectric material held between the first substrate and the second substrate;

a first electrode disposed between the dielectric material and the first substrate;

a second electrode disposed between the dielectric material and the first substrate,

wherein the first electrode is a common electrode of a pixel circuit and the second electrode is a pixel electrode of the pixel circuit;

a first sensing electrode, wherein the first sensing electrode and the common electrode of the pixel circuit are formed in a same first layer;

a second sensing electrode, wherein the second sensing electrode and the pixel electrode of the pixel circuit are formed in a same second layer; and

an electrostatic capacitance detection unit configured to produce a detection signal having an amplitude based on a capacitance formed between the first sensing electrode and the second sensing electrode through the dielectric material.