# US 2010/0165238 A1 · Liquid crystal display device

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- Number: US 2010/0165238 A1
- Document ID: US20100165238A1
- Status: Published application
- Kind: A1
- Application number: 12/647,007
- Filed: 2009-12-24
- Published: 2010-07-01
- Earliest claimed: 2008-12-25
- Assignees: Hitachi Displays, Ltd.; Panasonic Liquid Crystal Display Co., Ltd.
- Inventors: Daisuke KAJITA; Masahiro Ishii
- Web page: https://patentgrep.com/patent/US20100165238A1

## CPC

- G02F 1/133603: {with LEDs}
- G02F 2202/28: Adhesive materials or arrangements
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

The liquid crystal display device capable of reducing warp includes a liquid crystal display portion (6) and a backlight device (10) provided on a side opposite to a display surface of the liquid crystal display portion (6). The liquid crystal display portion (6) includes polarizing plates (1) and (2) and the backlight device (10) includes N (N≧1) optical members. When the N optical members are denoted by reference numerals 1, 2, . . . , and N in the stated order from a side on which the liquid crystal display portion (6) is provided, the optical member 1 is brought into intimate contact with the liquid crystal display portion (6) via an adhesive, and strain per unit length on the optical member 1 at least one of −10 to 10° C. and 40 to 70° C. is ⅕ or smaller of strain per unit length on the polarizing plates (1) and (2).

## Claims

### Claim 1

A liquid crystal display device, comprising:
a liquid crystal display portion; and
a backlight device provided on a side opposite to a display surface of the liquid crystal display portion, wherein:
the liquid crystal display portion comprises a polarizing plate;
the backlight device comprises N (N≧1) optical members; and
when the N optical members are denoted by reference numerals 1, 2, . . . , and N in the stated order from a side on which the liquid crystal display portion is provided,
the optical member 1 is brought into intimate contact with the liquid crystal display portion via an adhesive, and
strain per unit length on the optical member 1 at least one of −10 to 10° C. and 40 to 70° C. is ⅕ or smaller of strain per unit length on the polarizing plate.

### Claim 2

A liquid crystal display device, comprising:
a liquid crystal display portion; and
a backlight device provided on a side opposite to a display surface of the liquid crystal display portion, wherein:
the liquid crystal display portion comprises a polarizing plate;
the backlight device comprises N (N≧2) optical members; and
when the N optical members are denoted by reference numerals 1, 2, . . . , and N in the stated order from a side on which the liquid crystal display portion is provided,
the optical member 1 is brought into intimate contact with the liquid crystal display portion via an adhesive, and
the optical member M (1<M≦N) is brought into intimate contact with the optical member M−1 via an adhesive, and strain per unit length on an optical member having a highest flexural rigidity (product of Young' s modulus and second moment of area) among the N optical members at least one of −10 to 10° C. and 40 to 70° C. is ⅕ or smaller of strain per unit length on the polarizing plate.

### Claim 3 (depends on 1)

The liquid crystal display device according to claim 1, wherein:
at least one optical member of the N optical members has a surface with concavo-convex shape formed thereon; and
the liquid crystal display device further comprises a low refractive index layer having a refractive index of 1 or larger and 1.4 or smaller at the surface with the concavo-convex shape formed thereon one of between the optical member having the concavo-convex shape formed thereon and an optical member adjacent to the optical member having the concavo-convex shape formed thereon, or between the optical member having the concavo-convex shape formed thereon and the liquid crystal display portion.

### Claim 4 (depends on 1)

The liquid crystal display device according to claim 1, wherein:
at least one optical member of the N optical members is a light guide plate for guiding light emitted from a light source of the backlight device in a planar direction; and
the liquid crystal display device further comprises a low refractive index layer having a refractive index of 1 or larger and 1.4 or smaller on a light emitting surface side of the light guide plate one of between the light guide plate and an optical member adjacent to the light guide plate, or between the light guide plate and the liquid crystal display portion.

### Claim 5 (depends on 1)

The liquid crystal display device according to claim 1, wherein an optical member having a highest flexural rigidity among the N optical members comprises glass as a main material.

### Claim 6

A liquid crystal display device, comprising:
a liquid crystal display portion; and
a backlight device provided on a side opposite to a display surface of the liquid crystal display portion, wherein:
the liquid crystal display portion comprises:
a first polarizing plate on a light incident side;
a second polarizing plate on a light emitting side; and
a transparent layer provided on a light incident side of the first polarizing plate; and
when a thickness of the transparent layer is represented by ht and expressed as:
h
t
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0
=
ɛ
p
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2
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E
p

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p
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(
h
p
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h
g
)
-
ɛ
p
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1
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E
p
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1
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h
p
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(
h
p
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1
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ɛ
t
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E
t
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(
h
g
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h
p
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[
Equation
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1
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where ε, E, and h are strain per unit length under an environment in which temperature of the liquid crystal display portion is at least one of −10 to 10° C. and 40 to 70° C., and a Young's modulus, a thickness of each member, respectively, and indexes p1, p2, g, and t correspond to the first polarizing plate, the second polarizing plate, a substrate of the liquid crystal display portion, and the transparent layer, respectively, 0.5ht0≧ht≦1.5ht0 is satisfied.

### Claim 7

A liquid crystal display device, comprising:
a liquid crystal display portion; and
a backlight device provided on a side opposite to a display surface of the liquid crystal display portion, wherein:
the liquid crystal display portion comprises:
a first polarizing plate on a light incident side;
a second polarizing plate on a light emitting side; and
a transparent layer provided on a light emitting side of the second polarizing plate; and
when a thickness of the transparent layer is represented by ht and expressed as:
h
t


0
=
ɛ
p


1

E
p


1

h
p
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1

(
h
p
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1
+
h
g
)
-
ɛ
p
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2
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E
p
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2
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h
p
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2
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(
h
p
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2
+
h
g
)
ɛ
t
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E
t
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(
h
g
+
2

h
p


2
)
[
Equation


2
]
where ε, E, and h are strain per unit length under an environment in which temperature of the liquid crystal display portion is at least one of −10 to 10° C. and 40 to 70° C., and a Young's modulus, a thickness of each member, respectively, and indexes p1, p2, g, and t correspond to the first polarizing plate, the second polarizing plate, a substrate of the liquid crystal display portion, and the transparent layer, respectively, 0.5ht0≦ht≦1.5ht0 is satisfied.

### Claim 8 (depends on 6)

The liquid crystal display device according to claim 6, wherein the transparent layer comprises an optical member of the backlight device.

### Claim 9 (depends on 7)

The liquid crystal display device according to claim 7, wherein the transparent layer comprises a surface treated layer of the second polarizing plate.

### Claim 10 (depends on 6)

The liquid crystal display device according to claim 6, wherein the transparent layer comprises a support base provided on a side of the backlight device of the first polarizing plate.

### Claim 11 (depends on 7)

The liquid crystal display device according to claim 7, wherein the transparent layer comprises a support base provided on the light emitting side of the second polarizing plate.

### Claim 12 (depends on 1)

The liquid crystal display device according to claim 1, further comprising a frame member for, by pressing an end portion of the liquid crystal display portion from a light emitting surface side of the liquid crystal display portion, fixing a position of the liquid crystal display portion,
wherein a clearance between an outermost surface on the light emitting side of the liquid crystal display portion and the frame member is equal to or smaller than 1.5 mm.

### Claim 13 (depends on 6)

The liquid crystal display device according to claim 6, wherein:
the backlight device comprises N (N≧1) optical members;
no structure is provided for providing a clearance between the liquid crystal display portion and the backlight device; and
the liquid crystal display portion is directly mounted on the N optical members.