Polarizing Plate, Method for Produce Thereof, Optical Film, and Image Display Therewith

• US 20080137187A1
• Filed: 01/16/2006
• Published: 06/12/2008
• Est. Priority Date: 01/17/2005
• Status: Abandoned Application

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Kobayashi, Hiroaki, Takamura, Ryouichi, Tomoguchi, Naoki, Nishida, Kanji, Masuda, Tomoaki, Fujita, Yutaka
• Application Number:
  US11/795,295
• Publication Number:
  US 20080137187A1
• Time in Patent Office: Days
• US Class Current: 359/485
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 2201/50 Protective arrangements
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements

Abstract

A polarizing plate of the invention comprises a polarizing film; and a protective film bonded to one or both sides of the polarizing film with an adhesive layer or a pressure-sensitive adhesive layer interposed therebetween, wherein the adhesive layer or the pressure-sensitive adhesive layer has a thickness of 52 nm or less. Demand of in-plane uniformity of the polarizing plate is becoming severe due to recent size increase and image quality improvement of liquid crystal display. The polarizing plate has less stripe-like irregularities and good in-plane uniformity.

Claims

1. A polarizing plate, comprising:

a polarizing film; and

a protective film bonded to one or both sides of the polarizing film with an adhesive layer or a pressure-sensitive adhesive layer interposed therebetween, wherein the adhesive layer or the pressure-sensitive adhesive layer has a thickness of 52 nm or less.

2. The polarizing plate according to claim 1, wherein the polarizing film has a moisture percentage of 15 to 26% by weight when the protective film is bonded to one or both sides of the polarizing film with the adhesive layer or the pressure-sensitive adhesive layer interposed therebetween.

3. The polarizing plate according to claim 1, wherein the polarizing film has a thickness of 5 to 40 μ

m.

14. An optical film, comprising:

the polarizing plate according to claim 1; and

at least one optically functional layer laminated on the polarizing plate.

15. An image display, comprising the polarizing plate according to claim 1.

16. An image display, comprising the polarizing plate according to the optical film according to claim 14.

4. A method for producing a polarizing plate, comprising:

bonding a protective film to one or both sides of a polarizing film with an adhesive or a pressure-sensitive adhesive; and

then drying them by heating, wherein

the adhesive or the pressure-sensitive adhesive is laminated such that an adhesive layer or a pressure-sensitive adhesive layer having a thickness of 52 nm or less is formed after the drying.

5. The method according to claim 4, wherein the polarizing film has a controlled moisture percentage of 15 to 26% by weight when the protective film is bonded to one or both sides of the polarizing film with the adhesive or the pressure-sensitive adhesive.

6. The method according to claim 4, wherein the polarizing film has a thickness of 5 to 40 μ

m.

7. The method according to claim 4, wherein the bonding is conducted to apply the adhesive or the pressure-sensitive adhesive between the polarizing film and the protective film interposed and compress to pass them between a pair of a first roll and a second roll.

8. The method according to claim 7, wherein the first roll is a metal roll, and the second roll is an elastic roll comprising a metallic core coated with a rubber layer or a resin layer.

9. The method according to claim 8, wherein the first roll is an iron roll.

10. The method according to claim 8, wherein the rubber layer or the resin layer of the second roll has a hardness of 60 to 90.

11. The method according to claim 7, wherein the first and second rolls each have a roll diameter of 30 mm to 250 mm.

12. The method according to claim 4, wherein the protected film is bonded to one or both sides of the polarizing film with a dry lamination adhesive.

13. A polarizing plate, produced by the method according to claim 4.