Liquid crystal display device and turning film for liquid crystal display device

Patent metadata

Field	Value
Publication number	US-2018275334-A1
Application number	US-201815921055-A
Country	US
Kind code	A1
Filing date	Mar 14, 2018
Priority date	Mar 21, 2017
Publication date	Sep 27, 2018
Grant date	—

Abstract

A liquid crystal display device includes a liquid crystal panel, a light-guiding plate on a back face of the liquid crystal panel, at least one LED light source along an end face of the light-guiding plate, and a turning film between the liquid crystal panel and the light-guiding plate. The turning film includes a substrate layer and a prism array on a back face of the substrate layer. A retardation value of the substrate layer is no less than 180 nm and no greater than 415 nm. In a planar view: an intersection angle α between a transmission axis of the back face side-polarizing plate and ridge lines in the prism array is no less than 0° and less than 90°; the ridge lines are parallel to the end face; and an intersection angle between a slow axis of the substrate layer and the transmission axis is (45−α/2°).

First claim

What is claimed is:

1 . A liquid crystal display device comprising:
a liquid crystal panel; a light-guiding plate that is disposed on a back face side of the liquid crystal panel and is for guiding rays of light incident on an end face of the light-guiding plate toward a front face side; at least one LED light source disposed along the end face of the light-guiding plate; and a turning film disposed between the liquid crystal panel and the light-guiding plate, wherein the turning film comprises:
a substrate layer formed from a transparent resin; and
a prism array disposed on a back face side of the substrate layer, the liquid crystal panel comprises:
a liquid crystal cell; and
a back face side-polarizing plate disposed on a back face side of the liquid crystal cell,
a retardation value of the substrate layer of the turning film is no less than 180 nm and no greater than 415 nm, and in a planar view,
an intersection angle α between a transmission axis of the back face side-polarizing plate of the liquid crystal panel and a direction of ridge lines in the prism array of the turning film is no less than 0° and less than 90°,
the ridge lines in the prism array of the turning film are parallel to the end face of the light-guiding plate, and
an intersection angle between a slow axis of the substrate layer of the turning film and the transmission axis of the back face side-polarizing plate of the liquid crystal panel is (45−α/2°).

2 . The liquid crystal display device according to claim 1 , wherein the substrate layer comprises a polycarbonate as a principal component.

3 . The liquid crystal display device according to claim 1 , wherein the turning film further comprises, on a front face side of the substrate layer, at least one of a diffusion layer, a micro lens array or a reflective polarizing plate.

4 . The liquid crystal display device according to claim 1 , wherein prisms constituting the prism array each have an acute angle on the back face side.

5 . The liquid crystal display device according to claim 1 ,
wherein a reflective index of the prism array is no less than 1.35 and no greater than 1.70, and a difference between the refractive index of the prism array and a refractive index of the substrate layer is no less than 0.01 and no greater than 0.25.

6 . The liquid crystal display device according to claim 1 , wherein the prism array is elastic.

7 . The liquid crystal display device according to claim 1 , wherein the prism array is a resin molded product formed from an ultraviolet-curable resin.

8 . The liquid crystal display device according to claim 1 ,
wherein the light-guiding plate comprises, on a front face side thereof, a prism array or a lenticular lens array, and ridge lines on a front face of the light-guiding plate are perpendicular to the ridge lines in the prism array of the turning film in a planar view.

9 . A turning film that is for use in a liquid crystal display device comprising: a liquid crystal panel; a light-guiding plate that is disposed on a back face side of the liquid crystal panel and is for guiding rays of light incident on an end face of the light-guiding plate toward a front face side; and at least one LED light source disposed along the end face of the light-guiding plate,
the turning film being disposed between the liquid crystal panel and the light-guiding plate, and comprising:
a substrate layer comprising a polycarbonate as a principal component;
a prism array disposed on a back face side of the substrate layer; and
a diffusion layer that is disposed on a front face side of the substrate layer and is for diffusing transmitted rays of light,
wherein a retardation value of the substrate layer is no less than 180 nm and no greater than 415 nm, and a variation in an in-plane retardation value of the substrate layer is no greater than 50 nm, and an intersection angle between a slow axis of the substrate layer and a direction of ridge lines in the prism array of the turning film is no less than 45° and less than 90° in a planar view.

Assignees

• Keiwa Inc

Inventors

• Tsuji Takahiro

Classifications

• G02F1/133305

  Flexible substrates, e.g. plastics, organic film · CPC title

• G02F1/1335 Primary

  Structural association of cells with optical devices, e.g. polarisers or reflectors · CPC title

• G02B6/0051

  Diffusing sheet or layer · CPC title

• G02F1/133504

  Diffusing, scattering, diffracting elements (associated to illuminating devices G02F1/133606) · CPC title

• G02B6/0056

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