SENSING CIRCUIT, DISPLAY DEVICE AND ELECTRONIC APPARATUS

• US 20090273578A1
• Filed: 04/21/2009
• Published: 11/05/2009
• 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: OZAWA, Tokuro, TSUCHIYA, Yasushi, MATSUSHIMA, Toshiharu, KANDA, Eiji
• Granted Patent: US 8,766,946 B2
• Time in Patent Office: Days
• 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 first electrode disposed between the dielectric material and the first substrate;

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

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

2. The sensing circuit of claim 1,

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

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

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

3. The sensing circuit of claim 1,

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

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

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

4. The sensing circuit of claim 1,

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

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

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

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

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

a third electrode and a fourth electrode, the first electrode and the third electrode being formed on a same layer, the second electrode and the fourth electrode being formed on an other 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 electrode and the third electrode being formed on a same layer, the second electrode and the fourth electrode being formed on an other 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 electrode and the third electrode being formed on a same layer, the second electrode and the fourth electrode being formed on an other 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 first electrode and a second electrode disposed between the dielectric material and the first substrate; and

a distance between the first electrode and the second electrode being substantially constant in a plan view such that a capacitance formed between the first electrode and the second 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 electrode and the second electrode being independent of a distance between the first substrate and the second substrate.

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

14. The sensing circuit of claim 11, the first electrode and the second 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 electrode and the third electrode being formed on a same layer, the second electrode and the fourth electrode being formed on an other 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 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.

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.