Touch-sensitive liquid crystal display device with built-in touch mechanism

• US 20090295747A1
• Filed: 05/28/2009
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Abandoned Application

• Current Assignee: InnoLux Corporation
• Original Assignee: Innolux Display Corporation (InnoLux Corporation)
• Inventors: Hung, Chao-Yi, Hsieh, Yu-Lin
• Application Number:
  US12/455,073
• Publication Number:
  US 20090295747A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A touch-sensitive liquid crystal display (LCD) device includes a first substrate, a second substrate opposite to the first substrate, and a liquid crystal layer sandwiched between the first and second substrates. A first sensing line, a second sensing line, a reference capacitor, and a variable capacitor connected with the reference capacitor in series are arranged on the first substrate. A node between the reference capacitor and the variable capacitor is couple to the first and second sensing lines. A capacitance of the variable capacitor is changeable when acted upon an external pressure.

Claims

1. A touch-sensitive liquid crystal display (LCD) device comprising:

a first substrate;

a second substrate generally opposite to the first substrate;

a liquid crystal layer sandwiched between the first substrate and the second substrate;

a first sensing line and a second sensing line formed at an inner side of the first substrate on a side adjacent to the liquid crystal layer; and

a reference capacitor and a variable capacitor formed at the inner side of the first substrate, the reference capacitor and the variable capacitor electrically connected in series;

wherein a node between the reference capacitor and the variable capacitor is coupled to the first sensing line and the second sensing line, and a capacitance of the variable capacitor is changeable depending on an external pressure applied on the first substrate.

2. The touch-sensitive LCD device of claim 1, wherein the reference capacitor comprises a first electrode, a second electrode and an insulating layer sandwiched between the first electrode and the second electrode.

3. The touch-sensitive LCD device of claim 2, wherein the variable capacitor comprises a common electrode disposed on the first substrate on a side adjacent to the liquid crystal layer, the second electrode and the liquid crystal layer sandwiched between the common electrode and the second electrode.

4. The touch-sensitive LCD device of claim 3, further comprising a reference electrode line electrically connected to the first electrode on the first substrate.

5. The touch-sensitive LCD device of claim 3, wherein the second electrode is electrically connected to the first sensing line and the second sensing line.

6. The touch-sensitive LCD device of claim 3, further comprising a contact plug electrically connecting the second electrode to the first sensing line and the second sensing line.

7. The touch-sensitive LCD device of claim 3, wherein the capacitance of the variable capacitor is changeable according to a change to a thickness of the liquid crystal layer.

8. The touch-sensitive LCD device of claim 3, further comprising a spacer positioned between the common electrode and the second electrode, and a thickness of the spacer is smaller than a gap between the common electrode and the second electrode.

9. The touch-sensitive LCD device of claim 8, wherein the spacer is disposed on one of the common electrode and the second electrode.

10. The touch-sensitive LCD device of claim 3, further comprising a spacer disposed on the second substrate and covered by the common electrode, and a thickness of the spacer is smaller than a gap between the common electrode and the second electrode.

11. The touch-sensitive LCD device of claim 1, wherein the first substrate further comprises a thin film transistor (TFT), a pixel electrode, a scan line parallel to the first sensing line, and a data line parallel to the second sensing line formed thereon, the TFT comprising a gate electrically connected to the scan line, a source electrically connected to the data line, and a drain electrically connected to the pixel electrode.

12. The touch-sensitive LCD device of claim 1, further comprising a first readout circuit electrically connected to the first sensing line and a second readout circuit electrically connected to the second sensing line.

13. A touch-sensitive LCD device comprising:

a common electrode;

a first sensing line;

a second sensing line perpendicular to the first sensing line;

a reference capacitor corresponding to the common electrode, the reference capacitor comprising a first electrode and a second electrode, the second electrode being positioned between the first electrode and the common electrode; and

a liquid crystal layer sandwiched between the common electrode and the reference capacitor;

wherein when a distance between the common electrode and second electrode is changed, a touch signal is transmitted to the first sensing line and the second sensing line by the second electrode.

14. The touch-sensitive LCD device of claim 13, wherein the common electrode, the second electrode and the liquid crystal layer sandwiched therebetween define a variable capacitor, and a capacitance of the variable capacitor is changeable according to a change to a thickness of the liquid crystal layer.

15. The touch-sensitive LCD device of claim 13, further comprising a contact plug electrically connecting the second electrode to the first sensing line and the second sensing line.

16. The touch-sensitive LCD device of claim 13, further comprising a spacer positioned between the common electrode and the second electrode, a height of the spacer is smaller than a distance between the common electrode and the second electrode.

17. The touch-sensitive LCD device of claim 13, further comprising a spacer covered by the common electrode, and a thickness of the spacer is smaller than a gap between the common electrode and the second electrode.

18. The touch-sensitive LCD device of claim 13, further comprising a first substrate and a second substrate opposite to the first substrate.

19. The touch-sensitive LCD device of claim 18, wherein the first substrate further comprises a TFT, a pixel electrode, a scan line parallel to the first sensing line, and a data line parallel to the second sensing line formed on the first electrode formed thereon, the TFT comprising a gate electrically connected to the scan line, a source electrically connected to the data line, and a drain electrically connected to the pixel electrode.

20. The touch-sensitive LCD device of claim 13, further comprising a first readout circuit electrically connected to the first sensing line and a second readout circuit electrically connected to the second sensing line.