Touch sensor having a pressure detecting sensor with an electrode non-forming section

• US 9,690,414 B2
• Filed: 09/03/2015
• Issued: 06/27/2017
• Est. Priority Date: 10/04/2013
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kano, Hidekazu, Endo, Jun, Inoue, Takafumi, Kitada, Hiroaki
• Primary Examiner(s): Karimi, Pegeman
• Application Number:
  US14/844,453
• Publication Number:
  US 20150378493A1
• Time in Patent Office: 663 Days
• 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 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 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H10N 30/302 Sensors

Abstract

A touch sensor that includes a pressure detection sensor and a position detection sensor. The pressure detection sensor includes a piezoelectric film, a first piezoelectricity detecting electrode adjacent a first principal surface of the piezoelectric film, and a second piezoelectricity detecting electrode adjacent a second principal surface of the piezoelectric film. The position detection sensor includes a dielectric substrate, a plurality of first position detecting electrodes adjacent a first principal surface of the dielectric substrate, and a plurality of second position detecting electrodes adjacent a second principal surface of the dielectric substrate. In the pressure detection sensor, the second piezoelectricity detecting electrode includes an electrode non-forming section in a region where the first position detecting electrode and the second position detecting electrode overlap each other.

Claims

1. A touch sensor comprising:

a pressure detection sensor that includes a piezoelectric film having a first surface and a second surface, the first surface and the second surface being orthogonal to a thickness direction of the piezoelectric film, a first piezoelectricity detecting electrode adjacent the first surface, and a second piezoelectricity detecting electrode adjacent the second surface; and

an electrostatic position detection sensor that includes a dielectric substrate having a third surface and a fourth surface, the third surface and the fourth surface being orthogonal to a thickness direction of the dielectric substrate, a first position detecting electrode adjacent the third surface, and a second position detecting electrode adjacent the fourth surface,

wherein the pressure detection sensor and the electrostatic position detection sensor are arranged such that the first surface and the second surface are parallel to the third surface and the fourth surface, and

the second piezoelectricity detecting electrode includes an electrode non-forming section at a position where the first position detecting electrode and the second position detecting electrode overlap each other when the pressure detection sensor and the electrostatic position detection sensor are arranged such that the first surface and the second surface are parallel to the third surface and the fourth surface.

2. The touch sensor according to claim 1, wherein the first piezoelectricity detecting electrode is arranged over substantially a whole of the first surface.

3. The touch sensor according to claim 1, wherein the electrode non-forming section includes a first region that overlaps the second position detecting electrode.

4. The touch sensor according to claim 3, wherein the electrode non-forming section includes a second region that overlaps at least a part of the first position detecting electrode.

5. The touch sensor according to claim 4, wherein, in the first position detecting electrode, when the electrostatic type position detection sensor is viewed in the thickness direction of the dielectric substrate, a width of the first region that overlaps the second position detecting electrode is smaller than a width of a third region that does not overlap the second position detecting electrode.

6. The touch sensor according to claim 3, wherein, in the first position detecting electrode, when the electrostatic type position detection sensor is viewed in the thickness direction of the dielectric substrate, a width of the first region that overlaps the second position detecting electrode is smaller than a width of a second region that does not overlap the second position detecting electrode.

7. The touch sensor according to claim 1, further comprising a translucent layer interposed between the first piezoelectricity detecting electrode and the first surface of the piezoelectric film.

8. The touch sensor according to claim 1, wherein the piezoelectric film is polylactic acid stretched in a uniaxial direction.

9. The touch sensor according to claim 1, wherein the second piezoelectricity detecting electrode is in an insulating base film.

10. The touch sensor according to claim 1, wherein the second position detecting electrode is in an insulating base film.

11. The touch sensor according to claim 1, wherein in a region where the first position detecting electrode and the second position detecting electrode do not overlap each other, the touch sensor has a three-layer electrode structure in a thickness direction of the touch sensor.

12. The touch sensor according to claim 1, wherein a resistance of the second position detecting electrode is lower than that of the first position detecting electrode.