Touch panel and electronic device

• US 20020101410A1
• Filed: 01/16/2002
• Published: 08/01/2002
• 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
• Granted Patent: US 7,034,808 B2
• Time in Patent Office: Days
• 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 and having a predetermined spacing therebetween;

a pair of transparent electrodes having a respectively predetermined pattern, each of the transparent electrodes being formed on an inner surface of each of the pair of substrates; and

a plurality of projections formed on the surface of at least one of the pair of transparent electrodes, the projections being formed to have a substantially periodical pitch that is shorter than any wavelength of visible light.

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 ranging from 10 to 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 on a surface of the substrate and the transparent electrode being formed over the projection of the substrate.

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

14. 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.

15. 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.

16. An electronic device including a touch panel, comprising:

a lower substrate;

a flexible input substrate opposing the lower substrate and having a predetermined spacing therebetween;

a lower transparent electrode having a predetermined pattern formed on the inner surface of the lower substrate;

an input transparent electrode having a predetermined pattern formed on an inner surface of the input substrate so as to oppose the lower transparent electrode with a predetermined spacing therebetween; and

a plurality of projections formed on a surface of at least one of the lower transparent electrode and the input transparent electrode having a substantially periodical pitch that is shorter than any wavelength of visible light.