Touch panel and electronic device

• US 7,034,808 B2
• Filed: 01/16/2002
• Issued: 04/25/2006
• Est. Priority Date: 01/17/2001
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yoshida, Shohei, Iisaka, Hidehito, Sakata, Hidefumi, Takeuchi, Tetsuhiko
• Primary Examiner(s): Mengistu, Amare
• Application Number:
  US10/046,233
• Publication Number:
  US 20020101410A1
• Time in Patent Office: 1,560 Days
• Field of Search: 345173-178, 345/74.1, 345/75.2, 178/18.03, 178/18.05, 178/18.06, 200/512, 200/514, 359/454, 445 35- 37, 445/46, 445/47, 445/49
• US Class Current: 345/173
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

The present invention provides a touch panel having pluralities of projections, each of the projections having a predetermined shape, formed on inner surfaces of a lower substrate and an upper substrate, respectively. The projections being formed in at least two directions with a substantially periodical pitch that is shorter than any wavelength of visible light. The touch panel can also include a lower transparent electrode and an upper transparent electrode formed over the inner surfaces of the lower substrate and the upper substrate having the pluralities of projections, respectively. The cross-sectional area of each of the projections parallel to the outer surface of the lower substrate is configured to decrease continuously from bottom to top of the projection. The same applies to the combination of each of the projections, the bottom and a top thereof, and the upper substrate. Accordingly, this structure reduces the light reflection and diffraction at the boundary between an air space and the transparent electrode, thereby providing a resistive contact-type touch panel or a electrostatic capacitive coupling-type touch panel having high light transmittance.

Claims

1. A touch panel, comprising:

a pair of substrates opposing each other;

transparent electrodes formed on both of the pair of substrates, pairs of the transparent electrodes that face each other from different ones of the substrates being capable of selective contact with and separation from each other, the pair of transparent electrodes having an upper surface that locally protrudes, at a plurality of separate locations, substantially toward the other of the pair of transparent electrodes so that the pair of transparent electrodes are provided with a plurality of projections that are formed at a substantially periodical pitch that is shorter than any wavelength of visible light,

wherein the projections that are provided on one of the pair of transparent electrodes face the other projections that are provided on the other of the pair of transparent electrodes,

surfaces of the projections that are provided on both of the pair of transparent electrodes are formed from the transparent electrodes.

2. The touch panel according to claim 1, an air space being formed between the pair of transparent electrodes.

3. The touch panel according to claim 1, each of the projections becoming smaller from a bottom to a top thereof.

4. The touch panel according to claim 3, each of the projections becoming continuously smaller from the bottom to the top thereof.

5. The touch panel according to claim 3, each of the projections becoming smaller in a stepwise manner from the bottom to the top thereof.

6. The touch panel according to claim 3, each of the projections being formed as one of a truncated pyramid, a truncated cone, a pyramid and a cone.

7. The touch panel according to claim 1, the plurality of projections being arranged with a substantially periodical pitch in at least two directions.

8. The touch panel according to claim 1, the plurality of projections having a pitch shorter than 100 nm.

9. The touch panel according to claim 1, the plurality of projections being formed on surfaces of the pair of transparent electrodes.

10. The touch panel according to claim 9, the plurality of projections formed on the surface of one of the pair of transparent electrodes having the same pattern as that of the other transparent electrode.

11. The touch panel according to claim 9, the plurality of projections formed on the surface of one of the pair of transparent electrodes having a pattern different from that of the other transparent electrode.

12. The touch panel according to claim 1, each of the projections being formed by providing a projection of the transparent electrode on a flat substrate.

13. The touch panel according to claim 1, further comprising a plurality of spacers positioned between the pair of transparent electrodes that maintain the spacing between the pair of transparent electrodes.

14. The touch panel according to claim 1, the touch panel being at least one of an analog resistive contact type, a digital resistive contact type, and an electrostatic capacitive coupling type.

15. A touch panel, comprising:

a pair of substrates having inner surfaces that oppose each other and that have a predetermined spacing therebetween;

a pair of transparent electrodes formed in a predetermined pattern on the inner surfaces of the pair of substrates;

a spacer positioned between the pair of transparent electrodes; and

the transparent electrodes having an upper surface that locally protrudes, at a plurality of separate locations, substantially toward the other of the pair of transparent electrodes so that the pair of transparent electrodes are provided with a plurality of projections that are formed from a substantially periodical pitch that is shorter than any wavelength of visible light, contact between the pair of transparent electrodes initiating position detection,

wherein the projections that are provided on one of the pair of transparent electrodes face the other projections that are provided the other of the pair of transparent electrodes,

surfaces of the projections that are provided on both of the pair of transparent electrodes are formed from the transparent electrodes.

16. A touch panel, comprising:

a first substrate;

a second substrate opposing the first substrate and having flexibility;

a first transparent electrode formed over the first substrate from a conductive material, the first transparent electrode having a plurality of first projections at a substantially periodical pitch that is shorter than any wavelength of visible light, the plurality of first projections each having a first top that faces the second substrate, each first top being formed from the conductive material; and

a second transparent electrode formed over the second substrate from the conductive material, the second transparent electrode having a plurality of second projections at a substantially periodical pitch that is shorter than any wavelength of visible light, the plurality of second projections each having a second top that faces the first substrate, each second top being formed from the conductive material,

at least one of the first tops being selectively brought into physical contact with at least one of the second tops when the second substrate flexes, the physical contact resulting in an electrical connection.