KR101589347B1 - Module for liquid crystal display apparatus and liquid crystal display apparatus comprising the same - Google Patents

Abstract

The present invention relates to a liquid crystal display panel, A first polarizer formed on an upper surface of the liquid crystal display panel and including a first polarizer; And a second polarizer formed on a lower surface of the liquid crystal display panel and including a second polarizer, wherein an angle formed by the absorption axis of the first polarizer and the absorption axis of the second polarizer is -5 ° to + 5 ° And a retardation film on one of the lower portion of the first polarizer and the upper portion of the second polarizer, and a liquid crystal display device including the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a module for a liquid crystal display device, and a liquid crystal display device including the same. BACKGROUND OF THE INVENTION < RTI ID =

The present invention relates to a module for a liquid crystal display device and a liquid crystal display device including the same.

The polarizing plate includes a polarizer, and the polarizer generally has a polarizing property by stretching the polyvinyl alcohol film in the MD direction and molecular orientation of the polyvinyl alcohol. In the polarizer, when the direction perpendicular to the stretching direction is referred to as the TD direction, the shrinkage ratio differs between the MD direction and the TD direction. Generally, the shrinkage rate in the MD direction is larger than the shrinkage rate in the TD direction.

On the other hand, the liquid crystal display device includes polarizing plates on the upper and lower surfaces of the liquid crystal display panel, respectively. The upper polarizer formed on the upper surface of the liquid crystal display panel and the lower polarizer formed on the lower surface have a cutting angle of 90 ° for optical efficiency. Therefore, the MD directions of the upper polarizer and the lower polarizer are perpendicular to each other. As a result, the MD direction of the upper polarizer and the TD direction of the lower polarizer become parallel to each other, and the TD direction of the upper polarizer and the MD direction of the lower polarizer become parallel to each other. The shrinkage ratios in the MD direction and the TD direction are different from each other, so that the laminate of the upper polarizer plate / panel / lower polarizer plate can cause warpage. In particular, as the thickness of the liquid crystal display panel is being promoted in recent years, the occurrence of warpage may become larger. In this regard, Korean Patent Registration No. 10-0855837 discloses a polarizing plate, a manufacturing method thereof, and a liquid crystal display using the same.

SUMMARY OF THE INVENTION An object of the present invention is to provide a module for a liquid crystal display device which suppresses warping.

Another object of the present invention is to provide a module for a liquid crystal display device having an effect of preventing light leakage.

According to an aspect of the present invention, a module for a liquid crystal display device includes: a liquid crystal display panel; A first polarizer formed on an upper surface of the liquid crystal display panel and including a first polarizer; And a second polarizer formed on a lower surface of the liquid crystal display panel and including a second polarizer, wherein the retarder film comprises a retardation film on one of a lower portion of the first polarizer and an upper portion of the second polarizer, The angle formed between the absorption axis of the polarizer and the absorption axis of the second polarizer may be -5 ° to + 5 °.

The absorption axis of the first polarizer and the absorption axis of the second polarizer may be parallel to each other.

The absorption axis of the first polarizer may be the MD direction of the first polarizer.

The absorption axis of the second polarizer may be the MD direction of the second polarizer.

The first polarizer and the second polarizer may have different heat shrinkage ratios in the MD direction and the TD direction.

The retardation film may have an optical axis at an angle of (45 - X) to (45 + X) (X is 0 to 5) with respect to the absorption axis of the first polarizer or the second polarizer.

The retardation film may be a? / 2 retardation film (half wave plate).

The retardation film may be at least one selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, A polyvinyl chloride resin, a vinyl chloride resin, a polyvinylidene chloride resin, and the like.

And a protective film on at least one of the upper surface of the first polarizer and the lower surface of the second polarizer.

The protective film may further include at least one of an upper surface and a lower surface of the retardation film.

The liquid crystal display panel may include an IPS (In Place Switching) mode, a FFS (Fringe Field Switching) mode, a TN (Twisted Nematic) mode, and a VA (Vertical Alignment) mode liquid crystal display.

The liquid crystal display device according to another aspect of the present invention may include the liquid crystal display device module.

According to the present invention, there is provided a module for a liquid crystal display device having an anti-warp effect and an anti-light effect.

1 is a cross-sectional view of a module for a liquid crystal display device according to one embodiment of the present invention.
Fig. 2 is a schematic view of an optical axis direction and a light transmission direction in the module for a liquid crystal display of Fig. 1;
3 is a cross-sectional view of a module for a liquid crystal display device according to another embodiment of the present invention.
Fig. 4 is a schematic diagram of the orientation of the optical axis and the transmission direction of light in the module for the liquid crystal display of Fig. 3;
5 is a cross-sectional view of a module for a liquid crystal display of Comparative Example 1. Fig.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same names are used for the same or similar components throughout the specification.

In the present specification, 'upper' and 'lower' are defined with reference to drawings, and 'upper' may be changed to 'lower' and 'lower' may be changed to 'upper' depending on viewing time. In the present specification, 'parallel' does not need to be parallel to mathematical meaning but includes cases where the axis is substantially parallel, that is, the absorption axis is slightly distorted during the lamination process or the manufacturing process. In this specification, 'MD direction' means a stretching direction of a polyvinyl alcohol film for a polarizer, and 'TD direction' means a direction perpendicular to the MD direction. In the present specification, the term 'retardation film' means a half wave plate.

1 is a cross-sectional view of a module for a liquid crystal display device according to one embodiment of the present invention.

1, a module 500 for a liquid crystal display device includes a liquid crystal display panel 100, a first polarizer 200 formed on the upper surface of the liquid crystal display panel 100, And a second polarizer 300 formed between the liquid crystal display panel 100 and the light source 400. The first polarizer 200 includes a first polarizer 210, And a retardation film 230 formed on the lower surface of the first polarizer 210. The second polarizer 300 includes a second polarizer 310 and a second polarizer 310 And a fourth protective film 330 formed on the lower surface of the second polarizer 310. The absorption axis of the first polarizer 210 and the absorption axis of the second polarizer 310 are parallel to each other, The angle formed by the absorption axis of the first electrode 310 may be -5 degrees to +5 degrees. Specifically, the angle becomes -1 DEG to +1 DEG, more specifically 0 DEG, so that the absorption axes of the first polarizer of the first polarizer and the second polarizer of the second polarizer can be parallel to each other.

Generally, the polarizers of the polarizing plate formed on the upper and lower surfaces of the liquid crystal display panel are curling due to the mutual absorption axis being perpendicular to each other and shrinkage due to heat in the MD (machine direction) direction and the TD (transverse direction) ) May occur. When a polarizing plate is laminated on both surfaces of a liquid crystal display panel, the warping mainly occurs due to the heat shrinkage of the polarizer included in the polarizing plate. However, in the module of the present invention, the angle formed by the absorption axes of the polarizers formed on the upper and lower surfaces of the panel is -5 ° to + 5 °, specifically 0 °, so that the first polarizer and the second polarizer, It is possible to suppress the occurrence of warpage by offsetting the forces that cause warpage to each other.

1 and 2, the light emitted from the light source unit 400 is transmitted through the transmission axis perpendicular to the absorption axis 310a of the second polarizer 310, (Not shown in Fig. 2), passes through the liquid crystal display panel 100, and then passes through the transmission axis (which is perpendicular to the absorption axis 210a of the first polarizer 210 (Not shown). However, since the absorption axis 210a of the first polarizer 210 and the absorption axis 310a of the second polarizer 310 are parallel to each other, the light passes through the transmission axis of the first polarizer, have. Light leakage may degrade image quality.

1 and 2, a retardation film 230 is further provided on the lower surface of the first polarizer 201, as shown in FIG. 1, 210a, and 310a of the liquid crystal display panel is retarded by a half-wave phase in the direction crossing the direction of the liquid crystal display panel, and then the polarized light is linearly polarized in the direction crossed by 90 degrees so that all the light is absorbed by the first polarizer You can prevent the light from leaking. The retardation film is a? / 2 retardation plate and can realize the above-described function.

2, the retardation film 230 is disposed on the absorption axis 210a of the first polarizer 210 so as to have an optical axis 230a (slow axis) having a predetermined angle a with respect to the absorption axis 210a of the first polarizer 210, (45 - X) to (45 + X) (where X is 0 to 5). In the above range, light passing through the liquid crystal display panel is absorbed by the first polarizer, thereby preventing light from leaking.

The retardation film is not limited as long as it is a transparent plate having a? / 2 retardation function. In a specific example, the retardation film is a cellulose-based, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutyl Polyamide-based, polyimide-based, polyolefin-based, polyarylate-based, polyvinyl alcohol-based, polychlorinated-polyolefin-based, polycarbonate-based, polyether sulfone-based, Vinyl-based resin, polyvinylidene chloride-based resin, vinyl-based resin, and polyvinylidene chloride-based resin.

The retardation film may have a thickness of 10 to 100 mu m, preferably 10 to 50 mu m. In the above range, it can be used for a polarizing plate for a liquid crystal display device.

The polarizer is molecularly oriented in a specific direction, and when it is attached to a liquid crystal display device, only light in a specific direction is transmitted, and the polyvinyl alcohol film can be produced by dyeing iodine or a dichroic dye and stretching it in a certain direction . Specifically, it is produced through a swelling process, a dyeing step, a stretching step and a crosslinking step. Methods of performing each step are commonly known to those skilled in the art. The polarizer may have a thickness of 3 탆 to 100 탆. In the above range, it can be used for a polarizing plate for a liquid crystal display. The materials and thicknesses of the first polarizer and the second polarizer may be the same or different from each other.

The protective film may be a stretched or non-stretched film and may protect the polarizer or have a retardation in a predetermined range. The protective film may be a transparent optical film, and may be a polyester-based, cyclic-polyolefin-based, or poly-olefin-based film including cellulose-based, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, A film made of one or more resins selected from the group consisting of carbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride and polyvinylidene chloride . The protective film may have a thickness of 10 탆 to 500 탆. In the above range, it can be used for a polarizing plate for a liquid crystal display. The thickness and material of the first protective film, the second protective film, and the third protective film may be the same or different from each other.

An adhesive layer may be formed between the polarizer and the protective film and between the polarizer and the retardation film to increase the mechanical strength of the polarizing plate. The adhesive layer may include at least one of ordinary adhesives such as an aqueous adhesive, a pressure-sensitive adhesive, and a photocurable adhesive.

A protective film is further laminated on the upper surface or the lower surface of the retardation film to increase the mechanical strength of the polarizing plate.

The thickness of the polarizing plate may be 25 占 퐉 to 500 占 퐉. In the above range, it can be used for a polarizing plate for a liquid crystal display. The thickness, the degree of polarization, and the transmittance of the first polarizing plate and the second polarizing plate may be the same or different from each other.

An adhesive layer for adhering the polarizer and the liquid crystal display panel between the first polarizer and the liquid crystal display panel and / or between the second polarizer and the liquid crystal display panel, an adhesive layer, and a pressure-sensitive adhesive layer Or an adhesive layer may be used (a structure not using a film for protecting the PVA polarizer). The pressure-sensitive adhesive may include at least one of PVA resin, (meth) acrylic resin, isocyanate resin, and epoxy resin.

The polarizing plate can be attached to the liquid crystal display panel by a pressure sensitive adhesive. As the pressure sensitive adhesive, a conventional pressure sensitive adhesive known to those skilled in the art can be used. For example, a pressure sensitive adhesive can be used.

The liquid crystal display panel 100 includes a liquid crystal panel including a liquid crystal cell layer 110 sealed between a first substrate 120 and a second substrate 130. In one embodiment, ) Substrate (upper substrate), and the second substrate may be a TFT (Thin Film Transistor) substrate (lower substrate).

The first substrate and the second substrate may be the same or different, and may be a glass substrate or a plastic substrate. The plastic substrate is made of polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), polyethylene naphthalate (PEN), polyether sulfone (PES), polyarylate (PAR) and cycloolefin copolymer (COC) Or the like, but the present invention is not limited thereto.

The liquid crystal cell layer may be a liquid crystal layer including an IPS (In Place Switching) mode, a FFS (Fringe Field Switching) mode, a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode liquid crystal.

The light source unit may include a backlight unit as a normal light source unit included in the liquid crystal display device.

3 is a cross-sectional view of a module for a liquid crystal display device according to another embodiment of the present invention. 3, a module 1000 for a liquid crystal display device includes a liquid crystal display panel 100, a first polarizer 600 formed on the upper surface of the liquid crystal display panel 100, And a second polarizer 700 formed between the liquid crystal display panel 100 and the light source 400. The first polarizer 600 includes a first polarizer 610, And a second protective film 630 formed on the lower surface of the first polarizer 610. The second polarizer 700 includes a second polarizer 710, And a third protective film 720 formed on the lower surface of the second polarizer 710. The first polarizer 610 and the second polarizer 710 are disposed on the upper surface of the first polarizer 610, The angle formed by the absorption axis of the first electrode 710 may be -5 deg. To +5 deg., Specifically -1 deg. To +1 deg., More specifically 0 deg. Within this range, even if the first polarizing plate and the second polarizing plate are stacked on the liquid crystal display panel, the forces causing the warping are canceled out to each other, whereby the occurrence of warping can be suppressed.

3 and 4, the retardation film 730 includes a second polarizer 710 in a direction crossing the direction of the absorption axes 610a and 710a of the first polarizer and the second polarizer in the first direction The light passing through the liquid crystal display panel 100 is absorbed by the first polarizer 610 by retarding the direction of the transmitted light by a half-wave phase retardation and then polarizing it again in the direction intersecting the 90 ° direction. Can be prevented. 4, the retardation film 730 is disposed on the absorption axis 710a of the second polarizer 710 so as to have an optical axis 730a (slow axis) having an angle a within a predetermined range with respect to the absorption axis 710a of the second polarizer 710, (45 - X) DEG to (45 + X) DEG (where X is 0 to 5). In the above range, light passing through the liquid crystal display panel is absorbed by the first polarizer, thereby preventing light from leaking.

The liquid crystal display device according to another aspect of the present invention may include the liquid crystal display device module.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Specific specifications of the components used in the following examples and comparative examples are as follows.

(1) Polarizer material: polyvinyl alcohol film (VF-PS6000, Kuraray Co., Ltd., thickness: 60 m)

(2) retardation film: ZD12-260 (1330), manufacturer: ZEON company, thickness: 44 탆,? / 2 plate, Re at 260 nm, Rth at 220 nm, NZ at 1.34.

(3) Protective film: TAC film (ZFR25SL, Fuji, thickness: 25 mu m) was used.

For convenience, a polarizer formed on the upper surface of the liquid crystal display panel is referred to as an 'upper polarizer', a lower surface of the liquid crystal display panel, and a polarizer formed between the liquid crystal display panel and the backlight unit as a 'lower polarizer'.

Example  One

Polarizers were prepared by subjecting the material of the polarizer to a process such as dyeing and drawing. Specifically, the polyvinyl alcohol film was stretched three times at 60 ° C, adsorbed iodine, and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C to prepare a polarizer. A protective film was attached to the upper surface of the polarizer, and a retardation film was bonded to the lower surface of the polarizer using an adhesive to produce a first polarizing plate. A polarizer was prepared in the same manner, and a protective film was bonded to the upper and lower surfaces of the polarizer using an adhesive to prepare a second polarizing plate.

The first polarizing plate and the second polarizing plate are cut in a rectangular shape such that the long side is in the MD direction of the polarizer, and the first polarizing plate, the lower surface of the liquid crystal display panel, and the liquid crystal display panel are formed on the upper surface of the liquid crystal display panel having the IPS liquid crystal mode A second polarizing plate was disposed between the backlight units, and the absorption axis, which is the MD direction, was parallel to each other, thereby manufacturing a module for a liquid crystal display device.

Example  2

A first polarizing plate and a second polarizing plate were produced in Example 1, and the first polarizing plate and the second polarizing plate were cut in a rectangular shape such that the short sides thereof were in the MD direction of the polarizer, respectively. On the upper surface of the liquid crystal display panel having the IPS liquid crystal mode A second polarizing plate, a first polarizing plate on the lower surface, and an absorption axis in the MD direction were parallel to each other to produce a module for a liquid crystal display device.

Comparative Example  One

5 is a cross-sectional view of a liquid crystal display panel according to Comparative Example 1. Fig.

A polarizer was manufactured in the same manner as in Example 1 and protective films 12 and 13 were bonded to the upper and lower surfaces of the polarizer 11 to manufacture a third polarizer plate 10, Protective films 22 and 23 were adhered to the surface and the lower surface, respectively, to produce a fourth polarizing plate 20. The third polarizing plate 10 is cut in a rectangular shape such that the long side of the polarizer 11 is in the MD direction and is adhered to the upper surface of the liquid crystal display panel 100 having the IPS liquid crystal mode and the fourth polarizing plate 20 is fixed to the polarizer And the absorption axis 11a of the polarizer 11 and the absorption axis 21a of the polarizer 21 are disposed in the lower surface of the liquid crystal display panel 100, And was vertically adhered to produce a module having the structure of Fig.

Comparative Example  2

A module for a liquid crystal display was manufactured in the same manner as in Example 1, except that a protective film was used instead of the retardation film.

The module for a liquid crystal display manufactured in Examples and Comparative Examples was evaluated for light leakage. For convenience, the polarizer formed on the upper surface of the liquid crystal display panel is referred to as an 'upper polarizer', a lower surface of the liquid crystal display panel, and a polarizer formed between the liquid crystal display panel and the light source.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 The upper polarizer plate The first polarizer plate The second polarizer plate The third polarizer plate The first polarizer plate without the retardation film The lower polarizer plate The second polarizer plate The first polarizer plate The fourth polarizer plate The second polarizer plate Absorption axis relationship of the polarizer parallel parallel Perpendicular parallel Whether phase difference film is included include include Without Without Whether light blocking ○ ○ ○ × warp
Occurrence × × ○ ×

(1) Bending occurrence: A specimen was prepared by laminating a polarizing plate on the upper and lower surfaces of a 0.5 mm-thick glass plate using a pressure-sensitive adhesive. After 100 hours in the oven at 85 ° C, the height of the specimen from the bottom to the bottom of the specimen was measured using a height gauge. X was measured when the bending height from the floor was less than 5 mm, and when the bending height was 5 mm or more from the floor.

(2) Whether or not the light was blocked: When the prepared liquid crystal display module and the backlight unit were assembled and the light source was turned on in the backlight unit in the dark room, the prepared specimens were measured using a luminance measuring apparatus (RISA, Hiland). In the case of Examples 1 and 2 and Comparative Example 1, it is possible to measure with RISA equipment, but in the case of Comparative Example 2, it is impossible to measure with RISA. The specimen is placed on a liquid crystal display driven by a dark room and evaluated with a naked eye.

- ○: Most of the light from the liquid crystal display is interrupted, and black or blue texture, excellent.

- X: The light from the liquid crystal display is not blocked.

As shown in Table 1, it was confirmed that the module for a liquid crystal display of the present invention is shielded from light and has a low bending value so that bending hardly occurs. On the other hand, in the module of Comparative Example 1 in which the absorption axes of the polarizers of the upper polarizer and the lower polarizer were perpendicular to each other, it was confirmed that the light was blocked but the warp was large. Also, even if the absorption axes of the polarizers of the upper polarizer and the lower polarizer were parallel to each other, it was confirmed that the module of Comparative Example 2, which did not include the retardation film, did not block the light but did not block the light.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (15)

A liquid crystal display panel; A first polarizer formed on an upper surface of the liquid crystal display panel; And a second polarizer formed on a lower surface of the liquid crystal display panel,
Wherein the first polarizer includes a first polarizer, a protective film adhered to an upper surface of the first polarizer through an adhesive layer, and a retardation film bonded to the lower surface of the first polarizer through an adhesive layer,
Wherein the second polarizer comprises a protective film adhered to both sides of the second polarizer and the second polarizer through an adhesive layer,
The angle formed by the absorption axis of the first polarizer and the absorption axis of the second polarizer is -5 ° to + 5 °,
Wherein the retardation film has a thickness of 10 탆 to 50 탆,
The first polarizing plate and the second polarizing plate each have a thickness of 25 탆 to 500 탆,
The first polarizer and the second polarizer each have a thickness of 3 탆 to 100 탆,
Wherein the first polarizer and the second polarizer have different heat shrinkage ratios in the MD and TD directions. The module for a liquid crystal display device according to claim 1, wherein the absorption axis of the first polarizer is the MD direction of the first polarizer. The module for a liquid crystal display device according to claim 1, wherein the absorption axis of the second polarizer is the MD direction of the second polarizer. delete The liquid crystal display device according to claim 1, wherein the retardation film has an optical axis at an angle of (45 - X) ° to (45 + X) (X is 0 to 5) with respect to an absorption axis of the first polarizer or the second polarizer Module for liquid crystal displays. The module for a liquid crystal display device according to claim 1, wherein the retardation film is a? / 2 phase difference film. delete The film according to claim 1, wherein the retardation film is at least one selected from the group consisting of cellulose, polyester, cyclic polyolefin, polycarbonate, polyether sulfone, polysulfone, polyamide, polyimide, polyolefin, Wherein the film is made of one or more resins selected from the group consisting of polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride. delete delete delete delete The module for a liquid crystal display device according to claim 1, wherein the adhesive layer has a two-layer structure. The liquid crystal display module according to claim 1, wherein the liquid crystal display panel includes an in-place switching (IPS) mode, a fringe field switching (FFS) mode, a twisted nematic (TN) mode and a VA (Vertical Alignment) mode liquid crystal. A liquid crystal display device comprising the module for a liquid crystal display device according to any one of claims 1 to 3, 5 to 6, 8 and 13 to 14.

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