Piezoelectric sheet, touch panel using the same, and input-output device using them

• US 10,152,178 B2
• Filed: 11/12/2014
• Issued: 12/11/2018
• Est. Priority Date: 11/11/2013
• Status: Active Grant

• Current Assignee: Tianma Microelectronics Company Limited
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: Takatori, Kenichi
• Primary Examiner(s): Davis, David D
• Application Number:
  US14/539,383
• Publication Number:
  US 20150130770A1
• Time in Patent Office: 1,490 Days
• Field of Search: None
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

Disclosed is an active matrix liquid crystal display device with transverse electric field system, which improves afterimage. One electrode of many pixel comb electrodes is thicker in width than the other pixel comb electrode and common comb electrodes and is equal to a width of the common shield electrode covering through a second insulator film on video signal wirings. The display area is divided into two sub areas by the thick pixel comb electrode. The pixel comb electrode and the common comb electrode have the same number in each sub area. As the common shield electrode and the thick pixel comb electrode have the same width, the concentration of electric field can be eased near the pixel comb electrodes. The electric potential distribution becomes symmetric by symmetric configuration, reducing asymmetric lighting mode between frames. DC offset of the video signal after flicker adjustment decreases and the afterimage improves.

Claims

1. A piezoelectric sheet comprising:

an insulating layer;

a first conductive layer disposed on the insulating layer;

a piezoelectric layer disposed on the first conductive layer at a side thereof opposite the insulating layer; and

a second conductive layer disposed on the piezoelectric layer at a side thereof opposite the first conductive layer,

wherein the piezoelectric layer covers a surface of the second conductive layer, and

wherein the piezoelectric sheet is configured to detect a touch position at the insulating layer by monitoring variations in an electrical signal applied to the first conductive layer while fixing the second conductive layer at a prescribed voltage or a prescribed waveform, and

wherein the piezoelectric sheet is further configured to detect a touch pressure on the insulating layer by using both the piezoelectric layer and the second conductive layer in a time period different from a time period of detecting the touch position.

2. A piezoelectric sheet according to claim 1 further comprising:

a third conductive layer disposed at a predetermined distance from the second conductive layer at a side thereof opposite the first conductive layer.

3. A piezoelectric sheet according to claim 1, further comprising a plurality of electrodes connected electrically to the first conductive layer to fetch the electrical signal including data concerning the touch position on a surface of the insulating layer through the plurality of the electrodes and calculate the touch position on the surface based on the electrical signal.

4. A touch panel comprising:

the piezoelectric sheet according to claim 1,

wherein the second conductive layer is formed by patterning in a plurality of stripes, a signal applying means for applying a signal detecting the touch position in the first conductive layer, and a measurement means for measuring voltage at both ends of each stripe from the stripes of the second conductive layer formed by the patterning.

5. An input-output device using a touch panel according to claim 4.

6. An input-output device according to claim 5, wherein the device has the piezoelectric sheet, a position detection and coordinates calculation IC connected to the piezoelectric sheet, and a touch pressure detection IC connected to the piezoelectric sheet.

7. An input-output device according to claim 5, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold.

8. An input-output device according to claim 5, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold and a detected touch position.

9. An input-output device comprising:

the piezoelectric sheet according to claim 1,

a signal applying means for applying a signal detecting the touch position, and

a second signal applying means for applying a signal superposing a vibration generation signal on the signal detecting the touch position to the second conductive layer.

10. An input-output device comprising:

the piezoelectric sheet according to claim 1,

a signal applying means for applying a signal detecting the touch position, and

an acoustic generation signal applying means for driving the piezoelectric layer and producing sound by applying a signal between the first conductive layer and the second conductive layer.

11. An input-output device using a piezoelectric sheet according to claim 1.

12. An input-output device according to claim 11, wherein the device has the piezoelectric sheet, a position detection and coordinates calculation IC connected to the piezoelectric sheet, and a touch pressure detection IC connected to the piezoelectric sheet.

13. An input-output device according to claim 11, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold.

14. An input-output device according to claim 11, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold and a detected touch position.

15. A piezoelectric sheet comprising:

an insulating layer;

a first conductive layer disposed on the insulating layer;

a piezoelectric layer disposed on the first conductive layer at a side thereof opposite the insulating layer;

a second conductive layer disposed on the piezoelectric layer at a side thereof opposite the first conductive layer; and

a third conductive layer spaced a non-zero distance from the second conductive layer at a side thereof opposite the first conductive layer and in a direction in which the insulating layer, the first conductive layer, the piezoelectric layer, and the second conductive layer are sequentially disposed,

wherein the piezoelectric layer covers a surface of the second conductive layer, and

wherein the piezoelectric sheet is configured to detect a touch position at the insulating layer by monitoring variations in an electrical signal applied to the first conductive layer while fixing the second conductive layer at a prescribed voltage or a prescribed waveform and to detect a touch pressure on the insulating layer by using both the piezoelectric layer and the first conductive layer.

16. A piezoelectric sheet according to claim 15, further comprising a plurality of electrodes connected electrically to the first conductive layer to fetch the electrical signal including data concerning the touch position on a surface of the insulating layer through the plurality of the electrodes and calculate the touch position on the surface based on the electrical signal.

17. An input-output device using a piezoelectric sheet according to claim 15.

18. An input-output device according to claim 17, wherein the device has the piezoelectric sheet, a position detection and coordinates calculation IC connected to the piezoelectric sheet, and a touch pressure detection IC connected to the piezoelectric sheet.

19. An input-output device according to claim 17, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold.

20. An input-output device according to claim 17, wherein the device is configured to compare detected pressure with at least one memorized threshold and enable an operation according to the threshold and a detected touch position.