Liquid crystal display device and polarizing plate with a condensing element

Patent metadata

Field	Value
Publication number	US-9638955-B2
Application number	US-75412310-A
Country	US
Kind code	B2
Filing date	Apr 5, 2010
Priority date	Apr 6, 2009
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A liquid crystal display device according to the present invention includes a rear light source device, a rear polarizing plate, a liquid crystal cell including liquid crystal molecules that are substantially perpendicularly aligned during black display, and a front polarizing plate, which are provided in the stated order, wherein: an absorption axis of a polarizer of the rear polarizing plate is perpendicular to an absorption axis of a polarizer of the front polarizing plate; and condensed light in which a half-value angle in a direction perpendicular to the absorption axis of the polarizer of the rear polarizing plate is smaller than a half-value angle in a direction parallel to the absorption axis of the polarizer of the rear polarizing plate enters the rear polarizing plate. According to the present invention, a liquid crystal display device having an excellent front contrast ratio, and a polarizing plate with a condensing element for realizing the liquid crystal display device having the excellent front contrast ratio may be provided.

First claim

What is claimed is:

1. A liquid crystal display device, comprising a rear light source device, a rear polarizing plate, a liquid crystal cell including liquid crystal molecules that are substantially vertically aligned during black display, and a front polarizing plate, which are provided in the stated order, wherein:
an absorption axis of a polarizer of the rear polarizing plate is perpendicular to an absorption axis of a polarizer of the front polarizing plate;
condensed light in which a half-value angle Fw 1 in a direction perpendicular to the absorption axis of the polarizer of the rear polarizing plate is smaller than a half-value angle Fw 2 in a direction parallel to the absorption axis of the polarizer of the rear polarizing plate enters the rear polarizing plate,
the half-value angle Fw 1 in the direction perpendicular to the absorption axis of the polarizer of the rear polarizing plate is in a range of 7° to 30°, and
a ratio (Fw 2 /Fw 1 ) of the half-value angle Fw 2 to the half-value angle Fw 1 is equal to or larger than 1.2.; and,
further comprising a light diffusion element provided on an opposite side of the front polarizing plate with respect to the liquid crystal cell, wherein the light diffusion element diffuses light exited from the front polarizing plate in at least the direction perpendicular to the absorption axis of the rear polarizing plate.

2. A liquid crystal display device according to claim 1 , wherein the half-value angle of the condensed light in the direction perpendicular to the absorption axis of the polarizer of the rear polarizing plate is smaller than half-value angles in other directions.

3. A liquid crystal display device according to claim 2 , wherein the rear light source device emits the condensed light.

4. A liquid crystal display device according to claim 2 , further comprising a condensing element provided between the rear light source device and the rear polarizing plate, wherein the condensing element collimates light emitted from the rear light source device in a predetermined direction to convert the light into the condensed light.

5. A liquid crystal display device according to claim 1 , wherein the rear light source device emits the condensed light.

6. A liquid crystal display device according to claim 1 , further comprising a condensing element provided between the rear light source device and the rear polarizing plate, wherein the condensing element collimates light emitted from the rear light source device in a predetermined direction to convert the light into the condensed light.

Assignees

• Takemoto Hiroyuki
• Miyatake Minoru
• Nitto Denko Corp

Inventors

• Takemoto Hiroyuki
• Miyatake Minoru

Classifications

• G02F1/133615

  Edge-illuminating devices, i.e. illuminating from the side · CPC title

• G02F2001/133607

  Physics · mapped topic

• G02B6/0056

  for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements · CPC title

• G02F1/133606 Primary

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• G02F1/133607

  the light controlling member including light directing or refracting elements, e.g. prisms or lenses · CPC title