Color liquid crystal display devices

• US 20040218115A1
• Filed: 06/01/2004
• Published: 11/04/2004
• Est. Priority Date: 08/30/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Sako, Naoki, Kawana, Shin, Hisamune, Takayuki, Ootsuka, Reiji, Kijima, Naoto
• Granted Patent: US 7,006,172 B2
• Time in Patent Office: Days
• US Class Current: 349/71
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/004 Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

There are provided color liquid crystal display devices with high color purity of NTSC percentage of at least 80%.

A color liquid crystal display device comprises a combination of light shutters utilizing a liquid crystal 7, a color filter 9 having color elements of at least three colors of red, green and blue corresponding to the light shutters, and a backlight 1, 2 for transmission illumination. Under the following definitions: T^G(λ_n) represents a spectral transmittance at a wavelength λ_n nm (a wavelength at every 5 nm in the visible light region of from 380 to 780 nm) by a green pixel of the color filter 9; and I(λ_n) a relative emission intensity, normalized by a total emission intensity, at a wavelength λ_n nm from the backlight, these satisfy the following conditions (1) to (3):

(1) at one wavelength in 500 nm<λ_n<530 nm, I(λ_n)×T^G(λ_n)>0.01;

(2) in a wavelength region of 610 nm<λ_n<650 nm, I(λ_n)×T^G(λ_n)<0.0001;

(3) in a wavelength region of 400 nm<λ_n<450 nm, I(λ_n)'"'"'T^G(λ_n)<0.0001.

Claims

1. A color liquid crystal display device comprising a combination of light shutters utilizing a liquid crystal, a color filter having color elements of at least three colors of red, green and blue corresponding to the light shutters, and a backlight for transmission illumination,

wherein, under the following definitions:

λ

_n represents a wavelength at every interval of 5 nm in the visible light region of from 380 to 780 nm;

T^G(λ

_n) a spectral transmittance at a wavelength λ

_n nm by a green pixel of the color filter; and

I(λ

_n) a relative emission intensity, normalized by a total emission intensity, at a wavelength λ

_n nm from the backlight, these satisfy the following conditions (1) to (3);

(1) at one wavelength in 500 nm<

λ

_n<

530 nm,

I(λ

_n)×

T^G(λ

_n)>

0.01;

(2) in a wavelength region of 610 nm<

λ

_n<

650 nm,

I(λ

_n)×

T^G(λ

_n)<

0.0001;

(3) in a wavelength region of 400 nm<

λ

_n<

450 nm,

I(λ

_n)×

T^G(λ

_n)<

0.0001;

wherein I(λ

_n) is defined as follows;

$S<br><br>\left({\mathrm{\lambda <br><br>}}_n\right)=\frac{{\int <br><br>}_{{\mathrm{\lambda <br><br>}}_n-\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}/2}^{{\mathrm{\lambda <br><br>}}_n+\mathrm{\Delta <br><br>\lambda <br><br>}/2}<br><br>s<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br><br><br>\mathrm{\lambda <br><br>}}{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}}$$I<br><br>\left({\mathrm{\lambda <br><br>}}_n\right)=\frac{s<br><br>\left({\mathrm{\lambda <br><br>}}_n\right)}{\underset{\mathrm{\lambda <br><br>}=380}{\overset{780}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>s<br><br>\text{\hspace{1em}<br><br>}<br><br>\left({\mathrm{\lambda <br><br>}}_n\right)}$

where S(λ

) represents a measured value of emission intensity at a wavelength λ

from the backlight, and Δ

λ

=5 nm.

2. The color liquid crystal display device according to claim 1, wherein the backlight comprises a phosphor layer or a phosphor film, said phosphor layer or said phosphor film comprising a compound represented by the following general formula (4):

M^II_1-xEu_xO.a(Mg_1-yMn_y)O.bAl₂O₃ 

 

(4)

wherein M^II represents at least one atomic element selected from the group consisting of Ba, Sr and Ca and a, b, x and y are real numbers satisfying the following inequalities;

0.8≦

a≦

1.2,

4.5≦

b≦

5.5,

0.05≦

x≦

0.3, and

0.02≦

y≦

0.5.

3. The color liquid crystal display device according to claim 1, wherein the backlight has at least one emission peak in a wavelength region of from 500 to 530 nm,

wherein, where chromaticity points of red, green and blue pixels in the CIE XYZ calorimetric system are defined by (x_R,y_R), (x_G,y_G) and (x_B,y_B), respectively, an area of a triangle surrounded by said three points on an x-y chromaticity diagram is at least 80% of an area surrounded by the three primary colors, red (0.67, 0.33), green (0.21, 0.71) and blue (0.14, 0.08), in the standard system defined by U.S. National Television System Committee (NTSC).

4. The color liquid crystal display device according to claim 1, wherein the green pixel is formed from a photosensitive color resin composition comprising (a) a binder resin and/or (b) a monomer, (c) a photopolymerization initiation system and (d) a colorant, wherein said resin composition comprises an isoindolinone type pigment as (d) the colorant, and wherein said resin composition as a coating in a thickness of 2.5 μ

m shows an average transmittance of at least 20% and at most 80% at from 500 to 530 nm.

7. A color liquid crystal display device comprising a combination of light shutters utilizing a liquid crystal, a color filter having color elements of at least three colors of red, green and blue corresponding to the light shutters, and a backlight for transmission illumination,

wherein, under the following definitions:

T^R(λ

_n) represents a spectral transmittance at a wavelength λ

_n nm by a red pixel of the color filter; and

I(λ

_n) a relative emission intensity, normalized by a total emission intensity, at a wavelength λ

_n nm from the backlight, these satisfy the following conditions (5) and (6);

(5) at one wavelength in 615 nm≦

λ

_n≦

700 nm,

I(λ

_n)×

T^R(λ

_n)≧

0.01;

(6) at λ

_n=585 nm,

I(λ

_n)×

T^R(λ

_k)<

0.007;

wherein I(λ

_n) is defined by the same definition as in claim 1.

8. The color liquid crystal display device according to claim 7, wherein at one wavelength in 615 nm≦

λ

_n≦

700 nm, T^R(λ

_n) satisfies the following formula (7);

T^R(λ

_n)/T^R(585)>

8. 

 

(7)

9. The color liquid crystal display device according to claim 7, wherein the backlight comprises a phosphor layer or a phosphor film, said phosphor layer or said phosphor film comprising one or two or more selected from the group consisting of YVO₄:

Eu³⁺ type phosphors, Y(P,V)O₄;

Eu³⁺ type phosphors, and 3.5MgO.0.5MgF₂.GeO₂;

Mn⁴⁺ type phosphors.

10. The color liquid crystal display device according to claim 7, wherein the backlight comprises an LED in structure thereof, said LED comprising a GaAsP type LED.

11. The color liquid crystal display device according to claim 7, wherein the backlight has at least one emission peak in a wavelength region of from 615 to 700 nm.

5. A photosensitive color resin composition comprising (a) a binder resin and/or (b) a monomer, (c) a photopolymerization initiation system and (d) a colorant, said resin composition comprising an isoindolinone type pigment as (d) the colorant, wherein the resin composition as a coating in a thickness of 2.5 μ

m shows an average transmittance of at least 20% and at most 80% at from 500 to 530 nm.

6. A color filter wherein a green pixel is formed from the photosensitive color resin composition as defined in claim 5.

12. (Canceled)