Liquid crystal display device

Patent metadata

Field	Value
Publication number	US-2016154275-A1
Application number	US-201615015652-A
Country	US
Kind code	A1
Filing date	Feb 4, 2016
Priority date	Aug 12, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

A liquid crystal display device, in which a backlight unit, a light conversion member, a selective reflection member, a liquid crystal cell, and a display-side polarizer are disposed in this order, the backlight unit includes a light source that emits unpolarized light having a light emission central wavelength in a wavelength range of 300 nm to lower than 430 nm, the selective reflection member reflects 60% to 100% of the unpolarized light entering the selective reflection member and transmits at least some of light in a wavelength of higher than 430 nm to 650 nm, and the light conversion member includes an aligned fluorescent material that emits blue, green and red light which are linearly polarized in a vibration direction parallel to an absorption axis of the display-side polarizer, is improved in terms of the front surface luminance.

First claim

What is claimed is:

1 . A liquid crystal display device comprising:
a backlight unit, a light conversion member, a selective reflection member, a liquid crystal cell, and a display-side polarizer disposed in this order, wherein the backlight unit includes a light source that emits unpolarized light having a light emission central wavelength in a wavelength range of 300 nm to lower than 430 nm, the selective reflection member reflects 60% to 100% of the unpolarized light entering the selective reflection member and transmits at least some of light in a wavelength of higher than 430 nm to 650 nm, and the light conversion member includes an aligned fluorescent material that, due to the unpolarized light entering the light conversion member, emits blue light which has a light emission central wavelength in a wavelength range of 430 nm to 480 nm and is light linearly polarized in a vibration direction parallel to an absorption axis of the display-side polarizer, green light which has a light emission central wavelength in a wavelength range of 500 nm to 600 nm and is light linearly polarized in the vibration direction parallel to the absorption axis of the display-side polarizer, and red light which has a light emission central wavelength in a wavelength range of 600 nm to 650 nm and is light linearly polarized in the vibration direction parallel to the absorption axis of the display-side polarizer.

2 . The liquid crystal display device according to claim 1 ,
wherein the unpolarized light is made up of light in a first polarization state and light in a second polarization state, the selective reflection member sequentially includes a first selective reflection region and a second selective reflection region from a backlight side, the first selective reflection region reflects the light in the first polarization state out of the unpolarized light entering the first selective reflection region, transmits the light in the second polarization state while maintaining the polarization state, and transmits light in a wavelength range of higher than 430 nm to 650 nm, and the second selective reflection region reflects the light in the second polarization state which passes through the first selective reflection region and enters the second selective reflection region and transmits light in a wavelength range of higher than 430 nm to 650 nm.

3 . The liquid crystal display device according to claim 1 ,
wherein the selective reflection member sequentially includes a first dielectric multilayer film and a second dielectric multilayer film, the first dielectric multilayer film has a reflection central wavelength in a wavelength range of 300 nm to 430 nm, reflects light linearly polarized in a first direction at the reflection central wavelength, transmits light linearly polarized in a second direction orthogonal to the first direction, and transmits at least some of the light in a wavelength range of higher than 430 nm to 650 nm, and the second dielectric multilayer film has a reflection central wavelength in a wavelength range of 300 nm to 430 nm, reflects light linearly polarized in a second direction at the reflection central wavelength, and transmits at least some of the light in a wavelength range of higher than 430 nm to 650 nm.

4 . The liquid crystal display device according to claim 1 ,
wherein the selective reflection member sequentially includes a light reflection layer formed by fixing a first cholesteric liquid crystalline phase and a light reflection layer formed by fixing a second cholesteric liquid crystalline phase, the light reflection layer formed by fixing the first cholesteric liquid crystalline phase has a reflection central wavelength in a wavelength range of 300 nm to 430 nm, reflects any one of right-circularly-polarized light and left-circularly-polarized light at the reflection central wavelength, transmits the other light, and transmits at least some of the light in a wavelength range of higher than 430 nm to 650 nm, and the light reflection layer formed by fixing the second cholesteric liquid crystalline phase has a reflection central wavelength in a wavelength range of 300 nm to 430 nm, reflects circularly polarized light in a direction different from that of the light reflection layer formed by fixing the first cholesteric liquid crystalline phase at the reflection central wavelength, and transmits at least some of the light in a wavelength range of higher than 430 nm to 650 nm.

5 . The liquid crystal display device according to claim 1 , further comprising:
a backlight-side polarizer between the selective reflection member and the liquid crystal cell, wherein the backlight-side polarizer and the absorption axis of the display-side polarizer are orthogonal to each other.

6 . The liquid crystal display device according to claim 5 , further comprising:
two polarizing plate protective films on both surfaces of the backlight-side polarizer, wherein, out of the two polarizing plate protective films, at least the polarizing plate protective film on a selective reflection member side is a cellulose acylate film.

7 . The liquid crystal display device according to claim 1 ,
wherein the fluorescent material includes at least a quantum dot.

8 . The liquid crystal display device according to claim 7 ,
wherein the quantum dot is a quantum dot having an ellipsoidal shape or a rectangular parallelepiped shape.

9 . The liquid crystal display device according to claim 8 ,
wherein a long axis direction of the quantum dot is aligned in a direction parallel to the absorption axis of the display-side polarizer.

10 . The liquid crystal display device according to claim 1 ,
wherein the light conversion member is an aligned fluorescent sheet formed by dispersing and then stretching the fluorescent material.

11 . The liquid crystal display device according to claim 1 ,
wherein the blue light, the green light, and the red light emitted from the light conversion member all have a peak with a light emission intensity having a half bandwidth of 100 nm or smaller.

12 . The liquid crystal display device according to claim 1 ,
wherein the entire backlight unit is a surface light source.

13 . The liquid crystal display device according to claim 1 ,
wherein the light emission central wavelength of the unpolarized light emitted from the backlight unit is in a wavelength range of 300 nm to 380 nm.

14 . The liquid crystal display device according to claim 1 ,
wherein the unpolarized light emitted from the backlight unit has a peak with a light emission intensity having a half bandwidth of 30 nm or smaller.

15 . The liquid crystal display device according to claim 1 ,
wherein the backlight unit includes a reflection member capable of reflecting light in some or all of a wavelength range of 300 nm to 430 nm.

Assignees

• Fujifilm Corp

Inventors

• Saneto Ryuji
• Ohmuro Katsufumi

Classifications

• G02F1/133528

  Polarisers · CPC title

• G02F2001/133614

  Physics · mapped topic

• G02F1/13362

  providing polarized light, e.g. by converting a polarisation component into another one · CPC title

• G02F1/133553 Primary

  Reflecting elements (associated to illuminating devices G02F1/133605) · CPC title

• G02B5/26 Primary

  Reflecting filters (G02B5/28 takes precedence) · CPC title