Liquid crystal display module comprising a transparent media layer interposed between a reflection polarizing plate and an optical sheet

• US 8,928,843 B2
• Filed: 06/25/2007
• Issued: 01/06/2015
• Est. Priority Date: 06/26/2006
• Status: Active Grant

• Current Assignee: KEIWA, Inc.
• Original Assignee: KEIWA, Inc.
• Inventors: Harada, Kenichi
• Primary Examiner(s): Lee, Paul
• Application Number:
  US11/821,725
• Publication Number:
  US 20080123028A1
• Time in Patent Office: 2,752 Days
• Field of Search: 349/115
• US Class Current: 349/115
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 2202/40 Materials having a particular birefringence, retardation

Abstract

An object of the present invention is to provide an optical unit and a backlight unit which can markedly enhance utilization efficiency of rays of light and dramatically increase luminance, and which are suited for immediate beneath type liquid crystal display modules and the like. The optical unit of the present invention is a rectangular layered structural member having a reflection polarizing plate, an optical sheet superposed on the back face side of the reflection polarizing plate, and a transparent media layer filled between the reflection polarizing plate and the optical sheet. This optical sheet includes a resin substrate film having an optical anisotropy, and the absolute value of the angle of the crystal orientation of the substrate film with respect to the transmission axial orientation of the reflection polarizing plate is π/8 or greater and 3π/8 or less. The retardation value of the substrate film is preferably 70 nm or greater and 320 nm or less. The optical sheet preferably has an optical layer laminated on one face of the substrate film. The liquid crystal display module of the present invention has a liquid crystal display element, the optical unit, and an immediate beneath type backlight.

Claims

1. A rectangular liquid crystal display module comprising:

a liquid crystal display element in which a liquid crystal cell is sandwiched between a pair of polarizing plates;

an optical unit overlaid on the back face side of the liquid crystal display element; and

a surface illuminant backlight of immediate beneath type or opposed edge light type overlaid on the back face side of the optical unit;

wherein the optical unit is a rectangular layered structural member, comprising;

a reflection polarizing plate that splits reflected beams and transmitted beams on the basis of polarization characteristics;

an optical sheet superposed on a back face side of the reflection polarizing plate; and

a transparent media layer being interposed between the reflection polarizing plate and the optical sheet, said transparent media layer being comprised of a material having a volume which at least substantially fills a space between said back face side of said reflection polarizing plate and a confronting face of said optical sheet;

wherein the optical sheet includes a resin substrate film having an optical anisotropy, the absolute value of the angle of the crystal orientation of the substrate film with respect to the transmission axial orientation of the reflection polarizing plate is π

/8 or greater and 3π

/8 or less, and the retardation value of the substrate film is 70 nm or greater and 320 nm or less; and

wherein the reflection polarizing plate of the optical unit is a back face side-polarizing plate of the liquid crystal display element.