Touch panel and input device including the same

• US 20050099401A1
• Filed: 10/19/2004
• Published: 05/12/2005
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsumoto, Kenichi, Murakami, Tetsuo
• Granted Patent: US 7,714,845 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch panel includes a light-transmissible, piezoelectric substrate having a first surface and a second surface opposite to the first surface of the piezoelectric substrate, a first light transmissible, resistor layer provided on the first surface of the substrate, and a second light transmissible, resistor layer provided on the second surface of the substrate. A portion of the piezoelectric substrate, upon being pressed, has an electric resistance locally decreasing. The touch panel, even having a simple construction, can avoid reflections of external light and suppress a Newton'"'"'s ring.

Claims

1. A touch panel comprising:

a light-transmissible, piezoelectric substrate having a first surface and a second surface opposite to the first surface of the piezoelectric substrate, wherein a portion of the piezoelectric substrate, upon being pressed, has an electric resistance locally decreasing;

a first light transmissible, resistor layer provided on the first surface of the substrate; and

a second light transmissible, resistor layer provided on the second surface of the substrate.

2. The touch panel according to claim 1, wherein the piezoelectric substrate comprises poly-vinylidene fluoride.

3. The touch panel according to claim 1, further comprising:

first and second electrode layers provided on the first resistor layer and connected to the first resistor layer, the first and second electrode layers being arranged in a first direction; and

third and fourth electrode layers provided on the second resistor layer and connected to the second electrically resistor layer, the third and fourth electrode layers being arranged in a second direction non-parallel to the first direction.

4. The touch panel according to claim 3, wherein the first direction is orthogonal to the second direction.

5. The touch panel according to claim 1, further comprising a resin layer provided on the first resistor layer.

6. An input device comprising:

a touch panel including

a light-transmissible, piezoelectric substrate having a first surface and a second surface opposite to the first surface of the piezoelectric substrate, wherein a portion of the piezoelectric substrate, upon being pressed, has an electric resistance locally decreasing,

a first light transmissible, resistor layer provided on the first surface of the substrate,

a second light transmissible, resistor layer provided on the second surface of the substrate,

first and second electrode layers provided on the first resistor layer and connected to the first resistor layer, the first and second electrode layers being arranged in a first direction, and

third and fourth electrode layers provided on the second resistor layer and connected to the second electrically resistor layer, the third and fourth electrode layers being arranged in a second direction non-parallel to the first direction; and

a control circuit coupled to the first to fourth electrode layers, the control circuit being operable to determine a position of the pressed portion of the piezoelectric substrate.

7. The input device according to claim 6, wherein the piezoelectric substrate comprises poly-vinylidene fluoride.

8. The input device according to claim 6, wherein the first direction is orthogonal to the second direction.

9. The input device according to claim 6, wherein the control circuit is operable to supply a first voltage between the first electrode layer and the second electrode layer for determining the position of the pressed portion.

10. The input device according to claim 9,

wherein the control circuit is operable to supply a second voltage between the first resistor layer and the second resistor layer when the portion is pressed, and

wherein the supplied second voltage causes the piezoelectric substrate to vibrates.

11. The input device according to claim 10, wherein the second voltage is higher than the first voltage.