Touch panel and input device including the same

• US 7,714,845 B2
• Filed: 10/19/2004
• Issued: 05/11/2010
• Est. Priority Date: 11/07/2003
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsumoto, Kenichi, Murakami, Tetsuo
• Primary Examiner(s): Nguyen; Chanh
• Assistant Examiner(s): Ma; Calvin C
• Application Number:
  US10/967,136
• Publication Number:
  US 20050099401A1
• Time in Patent Office: 2,030 Days
• Field of Search: 345173-178
• 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 arranged to detect a position at which the touch panel is pushed by a user, the touch panel comprising:

a light-transmissible, piezoelectric substrate having a first surface and a second surface, the first surface and the second surface being on opposite sides of the piezoelectric substrate;

a first light transmissible, resistor layer provided on the first surface of the piezoelectric substrate, the first resistor layer having a predetermined area in which positions on the first resistor layer at which the first resistor layer is pushable by a user are electrically detectable;

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

first and second electrode layers provided on the first resistor layer and being connected to the first resistor layer, the first and second electrode layers being arranged at both ends of the first resistor layer, respectively, in a first direction; and

a control circuit operable to supply a voltage between the first and second electrode layers of the first resistor layer,

wherein the piezoelectric substrate is arranged such that the first surface of the piezoelectric substrate is positioned entirely on the predetermined area of the first resistor layer,

wherein the piezoelectric substrate, the first resistor layer and the second resistor layer are arranged such that, in response to the touch panel being pushed, the first resistor layer is pushed at a corresponding position which is located between the first and second electrode layers, and the piezoelectric substrate is pushed by the first resistor layer at a corresponding position on the piezoelectric substrate,

wherein a resistance of the piezoelectric substrate at the corresponding position on the piezoelectric substrate is smaller than that of surrounding portions of the piezoelectric substrate, and

wherein the control circuit is operable to determine the corresponding position of the first resistor layer based on a ratio of a voltage measured through the piezoelectric substrate to the voltage supplied between the first and second electrode layers.

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:

third and fourth electrode layers provided on the second resistor layer and connected to the second resistor layer, the third and fourth electrode layers being arranged at both ends of the second resistor layer, respectively, 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. The input device according to claim 1, wherein the corresponding position of the first resistor layer is arranged at the corresponding position of the piezoelectric substrate.

7. The input device according to claim 1, wherein the corresponding position of the first resistor layer is arranged at the corresponding position of the piezoelectric substrate.

8. An input device arranged to detect a position at which the input device is pushed by a user, the input device comprising:

a touch panel including

a light-transmissible, piezoelectric substrate having a first surface and a second surface, the first surface and the second surface being on opposite sides of the piezoelectric substrate,

a first light transmissible, resistor layer provided on the first surface of the piezoelectric substrate, the first resistor layer having a predetermined area in which positions on the first resistor layer at which the first resistor layer is pushable by a user are electrically detectable,

a second light transmissible, resistor layer provided on the second surface of the piezoelectric 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 at both ends of the first resistor layer, respectively, in a first direction, and

third and fourth electrode layers provided on the second resistor layer and connected to the second resistor layer, the third and fourth electrode layers being arranged at both ends of the second resistor layer, respectively, in a second direction non-parallel to the first direction,

wherein the piezoelectric substrate is arranged such that the first surface of the piezoelectric substrate is positioned entirely on the predetermined area of the first resistor layer,

wherein the piezoelectric substrate, the first resistor layer and the second resistor layer are arranged such that, in response to the input device being pushed, the first resistor layer is pushed at a corresponding position which is located between the first and second electrode layers and between the third and fourth electrode layers, and the piezoelectric substrate is pushed by the first resistor layer at a corresponding position on the piezoelectric substrate, and

wherein a resistance of the piezoelectric substrate at the corresponding position on the piezoelectric substrate is smaller than that of surrounding portions of the piezoelectric substrate; and

a control circuit coupled to the first to fourth electrode layers, the control circuit being operable to supply a first voltage between the first electrode layer and the second electrode layer, and to detect the corresponding position of the first resistor layer based on a ratio of a voltage measured through the piezoelectric substrate to the first voltage.

9. The input device according to claim 8, wherein the piezoelectric substrate comprises poly-vinylidene fluoride.

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

11. The input device according to claim 8,

wherein the control circuit is operable to supply a second voltage between the first resistor layer and the second resistor layer when the input device is pushed, and

wherein the supplied second voltage causes the piezoelectric substrate to vibrate by polarizing the piezoelectric substrate.

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

13. A touch panel arranged to detect a position at which the touch panel is pushed by a user, the touch panel comprising:

a light-transmissible, piezoelectric substrate having a first surface and a second surface, the first surface and the second surface being on opposite sides of the piezoelectric substrate;

a first light transmissible, resistor layer provided on the first surface of the piezoelectric substrate, the first resistor layer having a predetermined area in which positions on the first resistor layer at which the first resistor layer is pushable by a user are electrically detectable;

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

first and second electrode layers provided on the first resistor layer and being connected to the first resistor layer, the first and second electrode layers being arranged at both ends of the first resistor layer, respectively, in a first direction; and

a control circuit operable to supply a voltage to between the first and second electrode layers of the first resistor layer,

wherein the first resistor layer and the piezoelectric substrate are arranged such that an entirety of the predetermined area of the first resistor layer is in contact with the first surface of the piezoelectric substrate,

wherein the piezoelectric substrate, the first resistor layer and the second resistor layer are arranged such that, in response to the touch panel being pushed, the first resistor layer is pushed at a corresponding position which is located between the first and second electrode layers, and the piezoelectric substrate is pushed by the first resistor layer at a corresponding position on the piezoelectric substrate,

wherein a resistance of the piezoelectric substrate at the corresponding position on the piezoelectric substrate is smaller than that of surrounding portions of the piezoelectric substrate, and

wherein the control circuit is operable to detect the corresponding position of the first resistor layer based on a ratio of a voltage measured through the piezoelectric substrate to the voltage supplied between the first and second electrode layers.

14. The touch panel according to claim 13, wherein the piezoelectric substrate comprises poly-vinylidene fluoride.

15. The touch panel according to claim 13, further comprising:

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

16. The touch panel according to claim 15, wherein the first direction is orthogonal to the second direction.

17. The touch panel according to claim 16, further comprising a resin layer provided on the first resistor layer.

18. An input device arranged to detect a position at which the input device is pushed by a user, the input device comprising:

a touch panel including

a light-transmissible, piezoelectric substrate having a first surface and a second surface, the first surface and the second surface being on opposite sides of the piezoelectric substrate,

a first light transmissible, resistor layer provided on the first surface of the piezoelectric substrate, the first resistor layer having a predetermined area in which positions on the first resistor layer at which the first resistor layer is pushable by a user are electrically detectable,

a second light transmissible, resistor layer provided on the second surface of the piezoelectric 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 at both ends of the first resistor layer, respectively, in a first direction, and

third and fourth electrode layers provided on the second resistor layer and connected to the second resistor layer, the third and fourth electrode layers being arranged at both ends of the second resistor layer, respectively, in a second direction non-parallel to the first direction,

wherein the first resistor layer and the piezoelectric substrate are arranged such that an entirety of the predetermined area of the first resistor layer is in contact with the first surface of the piezoelectric substrate,

wherein the piezoelectric substrate, the first resistor layer and the second resistor layer are arranged such that, in response to the input device being pushed, the first resistor layer is pushed at a corresponding position which is located between the first and second electrode layers and between the third and fourth electrode layers, and the piezoelectric substrate is pushed by the first resistor layer at a corresponding position on the piezoelectric substrate, and

wherein a resistance of the piezoelectric substrate at the corresponding position on the piezoelectric substrate is smaller than that of surrounding portions of the piezoelectric substrate, the corresponding position of the first resistor layer being arranged at the corresponding position of the piezoelectric substrate; and

a control circuit coupled to the first to fourth electrode layers, the control circuit being operable to supply a first voltage between the first electrode layer and the second layer, and to detect the corresponding position of the first resistor layer based on a ratio of a voltage measured through the piezoelectric substrate to the first voltage.

19. The input device according to claim 18, wherein the piezoelectric substrate comprises poly-vinylidene fluoride.

20. The input device according to claim 18, wherein the first direction is orthogonal to the second direction.

21. The input device according to claim 18,

wherein the control circuit is operable to supply a second voltage between the first resistor layer and the second resistor layer when the input device is pushed, and

wherein the supplied second voltage causes the piezoelectric substrate to vibrate by polarizing the piezoelectric substrate.

22. The input device according to claim 21, wherein the second voltage is higher than the first voltage.