Display unit, manufacturing method thereof and electronic device equipped with same

• US 6,204,896 B1
• Filed: 02/10/1997
• Issued: 03/20/2001
• Est. Priority Date: 02/09/1996
• Status: Expired due to Term

• Current Assignee: Beijing Metis Technology Services Center
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Munemasa, Kimiko, Matsuhira, Tsutomu
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/796,684
• Time in Patent Office: 1,499 Days
• Field of Search: 349/12, 349/122, 349/155, 349/158, 349/187, 156/330, 156/276, 156/331.1, 156/274.8, 156/275.5, 156/279, 345/104, 345/173, 345/179, 178/18.03, 178/18.09, 178/19.04
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/136254 Checking; Testing
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A display unit comprises a transparent touch switch and a liquid crystal display having a display surface. At least an input area of the transparent touch switch is laminated to the display surface of the liquid crystal display by clear adhesive. The clear adhesive has a permeability after hardening which is close to the permeability of the liquid crystal display and the transparent touch switch. Clear fillers are disposed in the clear adhesive to prevent warping of the transparent touch switch and the liquid crystal display.

Claims

1. A display unit comprising:

a liquid crystal display having a display surface;

a transparent touch switch laminated on the display surface of the liquid crystal display;

a clear adhesive layer interposed between the display surface of the liquid crystal display and the transparent touch switch; and

a plurality of clear fillers disposed in the clear adhesive layer, the clear fillers comprising elastic spherical particles having a refractive index approximately equal to the refractive index of the clear adhesive layer.

2. A display unit according to claim 1;

wherein the transparent touch switch has a refractive index approximately equal to a refractive index of the clear adhesive layer.

3. A display unit according to claim 1;

wherein the liquid crystal display comprises a liquid crystal layer and a pair of transparent substrates sandwiching the liquid crystal layer therebetween.

4. A display unit according to claim 3;

wherein the refractive index of the clear adhesive layer is approximately equal to the refractive index of each of the transparent touch switch and the transparent substrates.

5. A display unit according to claim 1;

wherein the refractive index of the adhesive layer and that of the plastic spherical particles are within the range 1.47 to 1.57.

6. A display unit according to claim 5;

wherein the plastic spherical particles are all of the same size.

7. A display unit according to claim 6;

wherein the plastic spherical particles have a diameter of 12 microns.

8. A display unit according to claim 7;

wherein the plastic spherical particles have a diameter substantially less than the thickness of the adhesive layer.

9. A display unit according to claim 1;

wherein the plastic spherical particles have a diameter substantially less than the thickness of the adhesive layer.

10. A display unit according to claim 1;

wherein the plastic spherical particles have a diameter of 12 microns.

11. A display unit according to claim 1;

wherein the plastic spherical particles are all of the same size.

12. A display unit according to claim 11;

wherein the plastic spherical particles have a diameter substantially less than the thickness of the adhesive layer.

13. A display unit according to claim 1;

further including an input pen contactable with the transparent touch switch of the display unit for inputting information, the input pen having a mechanism for absorbing forces above a preselected value applied to the transparent touch switch by the input pen.

14. A display unit and input pen according to claim 13;

wherein the preselected value is within the range 200 g to 300 g.

15. A display unit and input pen according to claim 14;

wherein the mechanism comprises a spring.

16. A display unit and input pen according to claim 13;

wherein the preselected value is 200 g.

17. A display unit and input pen according to claim 13;

wherein the transparent touch switch comprises an analog resistance film touch switch; and

the preselected value is 100 g.

18. A method for manufacturing a display unit, comprising the steps of:

applying a clear adhesive to either a surface of a transparent touch switch or a display surface of a liquid crystal display, the clear adhesive containing a plurality of plastic spherical particles having a refractive index approximately equal to the refractive index of the clear adhesive; and

laminating the surface of the transparent touch switch to the display surface of the liquid crystal display.

19. A method for manufacturing a display unit as claimed in claim 18;

wherein the laminating step comprises disposing the transparent touch switch over the liquid crystal display, allowing the clear adhesive to flow between the surface of the transparent touch switch and the display surface of the liquid crystal display for a predetermined period of time, and curing the clear adhesive.

20. A method for manufacturing a display unit as claimed in claim 19;

wherein the curing step comprises irradiating ultraviolet rays over the clear adhesive.