OPTICAL DISPLAY DEVICE

• US 20130235306A1
• Filed: 03/08/2013
• Published: 09/12/2013
• Est. Priority Date: 03/09/2012
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: IKESHIMA, Kentaro, MIYATAKE, Minoru, NAKANO, Yuki
• Granted Patent: US 10,025,013 B2
• Time in Patent Office: Days
• US Class Current: 349/96
• CPC Class Codes: B29C 55/026 of preformed plates or sheets coated with a solution, a dispersion or a melt of thermoplastic material
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133531 characterised by the arrangement of polariser or analyser axes

Abstract

An optical display device which includes a display panel, and at least one polarizing film including a polyvinyl alcohol-based resin layer disposed on a viewing side with respect to the display panel, and having an optical arrangement forming a cross-Nicol relationship with regard to polarized light entering the polarizing film from the side of the display panel. The polarizing film is produced to have a thickness of 10 μm or less, by a method comprising the steps of: forming a polyvinyl alcohol-based resin layer on a resin substrate; stretching the polyvinyl alcohol-based resin layer integrally with the resin substrate; and dyeing the polyvinyl alcohol-based resin layer using a dichroic material. The polarizing film is disposed in the optical display device in a state in which a surface of the polarizing film as a contact surface with the resin substrate during the production thereof is oriented toward a side opposite to the display panel.

Claims

1. An optical display device comprising a display panel, and at least one polarizing film including a polyvinyl alcohol-based resin layer disposed on a viewing side with respect to the display panel, and having an optical arrangement forming a cross-Nicol relationship with regard to polarized light entering the polarizing film from the side of the display panel, wherein the polarizing film is produced to have a thickness of 10 μ

m or less, by a method comprising the steps of;

forming a polyvinyl alcohol-based resin layer on a resin substrate;

stretching the polyvinyl alcohol-based resin layer integrally with the resin substrate; and

dyeing the polyvinyl alcohol-based resin layer using a dichroic material, the polarizing film being disposed in the optical display device in a state in which a surface of the polarizing film as a contact surface with the resin substrate during the production thereof is oriented toward a side opposite to the display panel.

2. The optical display device as defined in claim 1, which is a liquid crystal display device or an organic EL display device.

3. The optical display device as defined in claim 2, which is a liquid crystal display device comprising a first polarizing film and a second polarizing film each produced to have a thickness of 10 μ

m or less, by a method comprising the steps of;

forming a polyvinyl alcohol-based resin layer on a resin substrate;

stretching the polyvinyl alcohol-based resin layer integrally with the resin substrate; and

dyeing the polyvinyl alcohol-based resin layer using a dichroic material, wherein;

the first polarizing film is disposed on the viewing side with respect to the display panel, in a state in which a surface of the first polarizing film as a contact surface with the resin substrate during the production thereof is oriented toward a side opposite to the display panel; and

the second polarizing film is disposed on a non-viewing side with respect to the display panel,

and wherein the first polarizing film forms the cross-Nicol relationship with regard to polarized light entering the first polarizing film from the side of the display panel after penetrating through the second polarizing film.

4. The optical display device as defined in claim 3, which is a liquid crystal display device, wherein the second polarizing film is disposed in a state in which a surface of the second polarizing film as a contact surface with the resin substrate during the production thereof is oriented toward a side opposite to the display panel.

5. The optical display device as defined in claim 3, which is a liquid crystal display device, wherein each of the first and second polarizing films comprises a protective layer provided at least on the side opposite to the display panel.

6. The optical display device as defined in claim 5, which is a VA-mode liquid crystal display device or an IPS-mode liquid crystal display device.

7. The optical display device as defined in claim 6, which is a VA-mode liquid crystal display device having a VA-mode liquid crystal cell as the display panel, wherein the VA-mode liquid crystal display device further comprises a phase difference film provided between the display panel and the first polarizing film.

8. The optical display device as defined in claim 6, which is an IPS-mode liquid crystal display device having an IPS-mode liquid crystal cell as the display panel.

9. The optical display device as defined in claim 2, which is an organic EL display device comprising the display panel, a ¼

wavelength phase difference film, a polarizing film and a protective film which are arranged in this other, the polarizing film being produced to have a thickness of 10 μ

m or less, by a method comprising the steps of;

forming a polyvinyl alcohol-based resin layer on a resin substrate;

stretching the polyvinyl alcohol-based resin layer integrally with the resin substrate; and

dyeing the polyvinyl alcohol-based resin layer using a dichroic material, wherein the polarizing film is disposed on the viewing side with respect to the display panel, in a state in which a surface of the polarizing film as a contact surface with the resin substrate during the production thereof is oriented toward a side opposite to the display panel, the polarizing film forming the cross-Nicol relationship with regard to polarized light which, after penetrating through the polarizing film from the viewing side and then undergoing a reflection at the display panel, re-enters the polarizing film from the side of the display panel.

10. The optical display device as defined in claim 1, wherein the polarizing film is produced by:

subjecting, integrally with a non-crystallizable ester-based thermoplastic resin substrate, a PVA-based resin layer applied and formed on the resin substrate, to a 2-stage stretching process consisting of preliminary in-air stretching and in-boric-acid-solution stretching; and

subjecting the PVA-based resin layer to a dyeing treatment using a dichroic material.