Pressure detector and touch panel provided with pressure detector

• US 9,519,378 B2
• Filed: 03/12/2014
• Issued: 12/13/2016
• Est. Priority Date: 12/18/2013
• Status: Expired due to Fees

• Current Assignee: Nissha Printing Company Limited (Nissha Co., Ltd.)
• Original Assignee: Nissha Printing Company Limited (Nissha Co., Ltd.)
• Inventors: Watazu, Yuji, Ozaki, Keisuke, Kakutani, Eiji, Shibata, Junichi
• Primary Examiner(s): FARAGALLA, MICHAEL A
• Application Number:
  US15/104,679
• Publication Number:
  US 20160320899A1
• Time in Patent Office: 1,007 Days
• US Class Current: 1/1
• CPC Class Codes: G01L 1/16 using properties of piezoelectric devices
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• 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 3/047 using sets of wires, e.g. crossed wires

Abstract

[Object] To provide a pressure detector capable of accurately detecting a pressing force.

[Solution] A pressure detector according to the present invention includes a first piezoelectric sheet 3a, a second piezoelectric sheet 3b located so as to be close to or in contact with the first piezoelectric sheet 3a, and a detection electrode 4 that sandwiches the first piezoelectric sheet 3a and the second piezoelectric sheet 3b. The first piezoelectric sheet 3a and the second piezoelectric sheet 3b are composed of materials having identical characteristics and have a thickness of 5 μm to 50 μm. Potential differences respectively generated between surfaces on a support substrate 1 side and surfaces opposite to the support substrate 1 of the first piezoelectric sheet 3a and the second piezoelectric sheet 3b when the first piezoelectric sheet 3a and the second piezoelectric sheet 3b are pulled in an in-plane direction have a relationship expressed by expression 1: V₁/V₂<0. In expression 1, V₁ and V₂ represent potential differences respectively generated between the surfaces on the support substrate 1 side and the surfaces opposite to the support substrate 1 of the first piezoelectric sheet 3a and the second piezoelectric sheet 3b.

Claims

1. A touch panel that measures a pressing force of a press applied to an input surface, comprising:

a plurality of upper electrodes located at intervals in one direction;

a plurality of lower electrodes that are located at intervals in a direction crossing the upper electrodes, on a side opposite to an input surface side of the upper electrodes, and that detect a press position between the upper electrodes and the lower electrodes;

a piezoelectric sheet including a first piezoelectric sheet located on a surface opposite to the input surface side of the lower electrodes and a second piezoelectric sheet located on a surface opposite to the input surface side of the first piezoelectric sheet so as to be close to or in contact with the first piezoelectric sheet;

first detection electrodes located in spaces between the lower electrodes in a cross-sectional view of the touch panel; and

a second detection electrode that is located on a surface opposite to the input surface side of the second piezoelectric sheet and that detects a potential difference generated in the piezoelectric sheet in cooperation with the first detection electrodes when the press is applied, wherein

the first piezoelectric sheet and the second piezoelectric sheet are composed of materials having identical characteristics and have a thickness of 5 μ

m to 50 μ

m,

potential differences respectively generated between surfaces on the input surface side and surfaces opposite to the input surface of the first piezoelectric sheet and the second piezoelectric sheet when the first piezoelectric sheet and the second piezoelectric sheet are pulled in an in-plane direction have a relationship expressed by expression 3;

V₁/V₂<

0, and

in expression 3,

V₁ represents V_1a−

V_1b,

V₂ represents V_2a−

V_2b,

V_1a represents a potential at the surface on the input surface side of the first piezoelectric sheet,

V_1b represents a potential at the surface opposite to the input surface side of the first piezoelectric sheet,

V_2a represents a potential at the surface on the input surface side of the second piezoelectric sheet, and

V_2b represents a potential at the surface opposite to the input surface side of the second piezoelectric sheet.

2. The touch panel according to claim 1, wherein the lower electrodes also function as the first detection electrodes.

3. A touch panel that measures a pressing force of a press applied to an input surface, comprising:

a plurality of upper electrodes located at intervals in one direction;

a plurality of lower electrodes that are located at intervals in a direction crossing the upper electrodes, on a side opposite to an input surface side of the upper electrodes, and that detect a press position between the upper electrodes and the lower electrodes;

a piezoelectric sheet including a first piezoelectric sheet located on a surface opposite to the input surface side of the upper electrodes and a second piezoelectric sheet located on a surface opposite to the input surface side of the first piezoelectric sheet so as to be close to or in contact with the first piezoelectric sheet, the first piezoelectric sheet and the second piezoelectric sheet being located between the upper electrodes and the lower electrodes;

first detection electrodes located in spaces between the upper electrodes in a cross-sectional view of the touch panel; and

second detection electrodes that are located in spaces between the lower electrodes in a cross-sectional view of the touch panel and that detect a potential difference generated in the piezoelectric sheet in cooperation with the first detection electrodes when the press is applied, wherein

the first piezoelectric sheet and the second piezoelectric sheet are composed of materials having identical characteristics and have a thickness of 5 μ

m to 50 μ

m,

potential differences respectively generated between surfaces on the input surface side and surfaces opposite to the input surface of the first piezoelectric sheet and the second piezoelectric sheet when the first piezoelectric sheet and the second piezoelectric sheet are pulled in an in-plane direction have a relationship expressed by expression 4;

V₁/V₂<

0, and

in expression 4,

V₁ represents V_1a−

V_1b,

V₂ represents V_2a−

V_2b,

V_1a represents a potential at the surface on the input surface side of the first piezoelectric sheet,

V_1b represents a potential at the surface opposite to the input surface side of the first piezoelectric sheet,

V_2a represents a potential at the surface on the input surface side of the second piezoelectric sheet, and

V_2b represents a potential at the surface opposite to the input surface side of the second piezoelectric sheet.

4. The touch panel according to claim 3, wherein the upper electrodes also function as the first detection electrodes.

5. The touch panel according to claim 3, wherein the lower electrodes also function as the second detection electrodes.