Liquid crystal display apparatus with touch-panel, and touch-panel

• US 6,611,299 B1
• Filed: 03/28/2000
• Issued: 08/26/2003
• Est. Priority Date: 08/04/1998
• Status: Expired due to Term

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Asaoka, Keizo, Fujii, Sadao, Hikida, Toshihiko
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US09/536,896
• Time in Patent Office: 1,246 Days
• Field of Search: 349/12, 349/117, 349/118, 345/173
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

The touch-panel equipped liquid crystal display apparatus has a polarizing plate, a ¼ wave plate, a touch panel, a ¼ wave plate, and a liquid crystal cell, which are disposed in the above-mentioned order from the display surface side. The arrangement is made such that the polarization axis of the polarizing plate and the slow axis within the film surface of the ¼ wave plate make an angle of 45° substantially, and the slow axis within the film surface of the ¼ wave plate and the polarization axis of the emission light from the liquid crystal cell make an angle of 45° substantially. Further, the slow axes of the ¼ wave plates and are arranged not in parallel with each other, or not cross over at right angles.

Claims

1. A touch-panel equipped liquid crystal display apparatus having a display surface comprising:

a polarizing plate A;

a ¼

wave plate a having a first film surface and a first slow axis within the first film surface;

a touch panel;

a ¼

wave plate B having a second film surface and a second slow axis within the second film surface; and

a liquid crystal cell that emits a light having a polarization axis extending in a direction, all disposed in the aforementioned order from the display surface, wherein;

the first slow axis within the first film surface of the ¼

wave plate A is in a horizontal direction of 0°

or in a vertical direction of 90°

as viewed from the display surface;

the second slow axis within the second film surface of the ¼

wave plate B is substantially at a diagonal position to the direction in which the polarization axis of the light emitted from the liquid crystal cell extends; and

the first slow axis of the ¼

wave plate A and the second slow axis of the ¼

wave plate B are nonparallel with each other without crossing at right angles.

2. A touch-panel equipped liquid crystal display apparatus according to claim 1, wherein, where a refractive index in the slow axis direction within the film surfaces of the ¼

wave plates A and B is represented by nx, a refractive index in a direction perpendicular to the slow axis is represented by ny, and a refractive index in a film thickness direction is represented by nz,

at least one of the wave plates has a relationship nz>

ny.

3. A touch panel-equipped liquid crystal display apparatus according to claim 1 or 2, wherein in that the liquid crystal cell is a super twist nematic-type liquid crystal cell.

4. A touch-panel equipped liquid crystal display apparatus according to claim 3, wherein the ¼

wave plate A serves also as a display surface side electrode substrate of the touch panel.

5. A touch-panel equipped liquid crystal display apparatus according to claim 2, wherein the ¼

wave plate A serves also as a display surface side electrode substrate of the touch panel.

6. A touch-panel equipped liquid crystal display apparatus according to claim 1, wherein the ¼

wave plate A serves also as a display surface side electrode substrate of the touch panel.

7. A touch-panel equipped liquid crystal display apparatus according to claim 1, wherein the liquid crystal cell further includes a new polarizing plate B on its display surface side, separately from the polarizing plate A.

8. A touch panel wherein the ¼

wave plates A and B and the touch panel according to claim 1, are laminated into an integral body, and the ¼

wave plate A is laminated on the display surface side of the touch panel, whereas the ¼

wave plate B is laminated on the opposite side surface of the touch panel.

9. A touch panel according to claim 8, wherein the ¼

wave plate A serves also as a display surface side electrode substrate of the touch panel.