KR20090089076A - Sheet for back light unit of liquid crystal display - Google Patents

Abstract

A sheet for a backlight unit of a liquid crystal display is provided to have a color adjustment function in a sheet for a backlight unit, thereby moving color coordinates of an LCD backlight in a desired direction. A polyester base film(1) is transparent. A binder resin(3) is transparent in the base film. A coating layer is coated by coating solution including a transparent resin particle(2). Color control elements are mixed in the binder resin of the coating layer.

Description

Sheet for backlight unit of liquid crystal display {SHEET FOR BACK LIGHT UNIT OF LIQUID CRYSTAL DISPLAY}

The present invention relates to a sheet for a backlight unit of a liquid crystal display, and more particularly, by having the LCD backlight unit sheet has a color control function, the color coordinates of the LCD backlight can be moved in a desired direction, and the existing color coordinates do not match. The present invention relates to a sheet for a backlight unit of a liquid crystal display that can use an LED light source that cannot be used for an LCD.

BACKGROUND ART In general, LCD backlight unit sheets are used for small to medium sized applications such as car navigation, mobile phones, PDAs, digital cameras, portable TVs, camcorders, and notebook PCs and desktop monitors.

Such LCD backlight units are classified into edge type backlight units provided with linear lamps on one end surface of the light guide plate, or side type backlight units provided with one or more lamps. The LCD backlight unit sheet has a concealment function to erase the shape of the diffusion dot (DOT) and the V-shaped cross-section installed at the bottom of the light guide plate to obtain an angle to send light to the upper part of the light guide plate, and an uneven light source from the light guide plate. The shape of the prism sheet, which protects the prism sheet and the prism sheet to increase the vertical light, the diffuser sheet that functions to switch to uniform light centered on the front of the backlight unit, and increases the vertical light to brighten the brightness. It can be roughly divided into an image diffusion sheet etc. which conceal a, and is called a light diffusion sheet collectively a lower diffusion sheet and an image diffusion sheet.

Recently, an LCD backlight unit using LEDs as a light source without using a conventional cold cathode ray tube (CCFL) has also been used. LCD backlight unit using LED as a light source has advantages in power consumption, color reproducibility, brightness, etc. compared to LCD backlight unit using CFFL, but it is still expensive and difficult to control color. Has its drawbacks. In the function of the light diffusion sheet for the LCD backlight unit, in order to perform the concealment function and the diffusion function and to improve the vertical brightness, to form a light diffusion layer by applying organic particles or inorganic particles on a transparent base film with a transparent binder resin And a light diffusion sheet having the same are known [Japanese Patent Laid-Open No. 7-174909, Korean Patent Publication Nos. 2000-0027862 and 1998-0020430].

However, the conventional light diffusion sheet for an LCD backlight unit as shown in FIG. 1 mainly forms a light diffusion layer using transparent organic resin of a polymethyl methacrylate component and a transparent binder resin for adhesion of the particles, and simply the particles on the surface thereof. It uses curves to condense light and improves vertical brightness. The prism sheet also improves the vertical luminance by collecting light.

Recently, there is a problem in that color coordinates do not coincide with the use of LEDs as LED light sources as compared with the conventional cold cathode ray tube (CCFL). In the current LED process, LEDs with a wide range of color coordinates are produced at the same time, and only a part of the produced LED products can be used for LCD backlights.

The present invention has been made to solve the above problems, an object of the present invention is to have a color control function on the LCD backlight unit sheet to move the color coordinates of the LCD backlight in the desired direction, the existing color coordinates do not match It is to provide a sheet for a backlight unit of the liquid crystal display that can use the LED light source that was not available because of the LCD.

The object is an LCD backlight unit sheet comprising a transparent polyester base film and a coating layer formed by coating a coating liquid containing a transparent binder resin and transparent resin particles on at least one surface of the base film, the sheet comprising a color control component. It is achieved by a sheet for a backlight unit of a liquid crystal display, characterized in that.

Here, the color control component is characterized in that the color control material mixed in the binder resin of the coating layer.

In addition, the color control component is characterized in that the color control transparent resin particles contained in the coating layer.

In addition, the color control component is characterized in that the color control material contained in the base film.

Preferably, an antistatic layer is further included on at least one surface of the backlight unit sheet of the liquid crystal display.

In addition, the object is made of a light collecting layer formed by applying a transparent polyester base film and a coating liquid containing a transparent binder resin on at least one surface of the base film, characterized in that it comprises a color control component.

The color control component is characterized in that the color control material mixed in the binder resin of the light collecting layer.

In addition, the color control component is characterized in that the color control material contained in the base film.

According to the present invention, it is possible to move the color coordinates of the LCD backlight in a desired direction by having a color control function on the sheet for the LCD backlight unit, and to use an LED light source that cannot be used because the existing color coordinates do not match. Has an effect.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

In the present invention, there is a problem in that the color coordinates do not coincide with the use of the LED as an LED light source, compared with the conventional cold cathode ray tube (CCFL), and the range of the color coordinates in the current LED process is limited. A wide LED is produced at the same time and only a part of the produced LED products can be used for the LCD backlight, and the present inventors have a color control function on the LCD backlight unit sheet so that the existing color coordinates do not match. It was confirmed that the LED light source that could not be used for the LCD to complete the present invention is not limited to the LED light source.

The optical function of the light diffusing layer is determined by the lens shape or the bend shape of the surface formed by the light diffusing agent. The optical function of the light diffusing sheet can be divided into two types, which are diffusion function and luminance function.

2 is a cross-sectional view of a sheet for a backlight unit of a liquid crystal display according to an embodiment of the present invention, Figure 3 is a cross-sectional view of a sheet for a backlight unit of a liquid crystal display according to another embodiment of the present invention, Figure 4 is a view of the present invention Another example is a cross-sectional view of a sheet for a backlight unit of a liquid crystal display. Looking at this in more detail, Figure 2 is a sheet having a color control function by putting a color control material in the coating layer, Figure 3 is a sheet using a transparent resin particles having a color control function, Figure 4 comprises a color control material It is a sheet using a base film.

The backlight unit sheet of the liquid crystal display according to the present invention is coated with a transparent polyester base film (1), a coating liquid containing a transparent binder resin (3) and transparent resin particles (2) on at least one surface of the base film An LCD backlight unit sheet comprising the formed coating layer, characterized in that it comprises a color control component.

The coating layer may be a light diffusion layer.

It is preferable that the said color control component is the color control material 4 mixed with the said binder resin 3 of the said application layer.

In addition, the color control component may be a color control material contained in the base film (1). That is, the base film 1 may be a color control material-containing base film 6 containing the color control material. Along with this, the color control material 4 mixed with the binder resin 3 of the coating layer or the color control transparent resin particles 5 included in the coating layer may be configured.

As the color control material, metal complex dyes (METAL COMPLEX DYE) as well as a color or a material selected from the color and the dye is preferably selected alone or mixed thereof.

In addition, the color control component is preferably a color control transparent resin particles (5) contained in the coating layer, the color control transparent resin particles (5) is selected alone or a mixture of common color bead (color bead) material It is preferably in form.

The transparent polyester base film 1 of the backlight unit sheet of the liquid crystal display according to the present invention has a light transmittance of 85 to 95%, preferably 90 to 94%.

In addition, in order to improve adhesion and coating property of the base film and the coating layer, the base film may be used after the primer treatment, corona or plasma treatment.

The binder resin (3) used in the coating layer should be transparent, for example, acrylic, urethane, epoxy, vinyl, polyester, polyamide, etc. of polymethyl methacrylate or methacrylic acid ester copolymer. It is possible to use alone or a mixture thereof selected from among resins.

The transparent resin particles 2 used in the coating layer may be spherical transparent particles, and organic particles such as acrylic particles, styrene particles, and silicon particles, and inorganic particles such as synthetic silica, glass beads, and diamond may be used. These light diffusing agents may be used alone or in combination of two or more thereof.

In addition, the sheet for a backlight unit of the liquid crystal display according to the present invention can be equally applicable to a prism sheet or a micro lens type sheet composed of a base film and a light collecting layer as well as a light diffusing sheet composed of a base film and a light diffusing layer.

The backlight unit sheet of the liquid crystal display according to the present invention is composed of a light-condensing layer formed by applying a transparent polyester base film and a coating liquid containing a transparent binder resin on at least one surface of the base film, and comprising a color control component. It features.

The color control component may be a color control material mixed with the binder resin of the light collecting layer or a color control material included in the base film.

Color control material used in this patent can be used as any color material as well as the general dye (Dye), and the transparent resin particles having a color control function is not limited to any components, but all transparent resins having a color Particles can be used.

In the production of the sheet for the backlight unit of the liquid crystal display according to the present invention, the method of applying the coating liquid on the transparent base film can be used without particular limitation, but preferably a knife coating, gravure transfer coating, reverse roll coating method Can be used. In addition, the shape of the coating layer may be compressed by using a mold having a shape in order to obtain a surface shape.

In addition, the sheet for the backlight unit of the liquid crystal display according to the present invention provides a slip property to one side or both sides of the transparent polyester base film, to suppress the scratches generated during the cutting and assembly work, and to prevent the mixing of foreign matters An antistatic layer can be formed.

Hereinafter, the present invention will be described in detail by way of examples. In the present embodiment, only the light diffusing sheet composed of the base film and the light diffusing layer will be described. However, the prism sheet or the micro lens type sheet made of the base film and the light collecting layer can be applied in the same manner.

Example 1

A sheet was prepared by applying a coating solution having the following composition to one surface of a transparent polyester film (XG-6DF2P, 100 µm, Toray Industries, Inc.) using a bar coater to form a light diffusion layer, and then drying at 120 ° C. for 2 minutes.

Composition of Coating Liquid

Binder Resin (Aekyung A811): 15.0 wt%

Curing agent (Aekyung DN980S): 1.5 wt%

-Synthetic Resin Particle (KOLON KS-1000 Silicon Particle): 25.5 wt%

Methyl ethyl ketone: 57.95 wt%

-Color regulator (Blue): 0.05% by weight

Example 2

In the same manner as in Example 1, except that the light diffusion layer was formed on one surface of the same transparent polyester film as that of Example 1 (XG-6DF2P, 100 µm), using the coating liquid having the following composition. To produce a sheet.

Composition of Coating Liquid

Binder Resin (Aekyung A811): 15.0 wt%

Curing agent (Aekyung DN980S): 1.5 wt%

-Synthetic Resin Particle (KOLON KS-1000 Silicon Particle): 25.5 wt%

Methyl ethyl ketone: 57.95 wt%

-Color regulator (RED): 0.05 wt%

Example 3

Except for forming a light diffusion layer using a coating liquid having the following composition on one surface of the same transparent polyester film (Toray Saehan XG-6DF2P, 100㎛) as in Example 1, the same as in Example 1 To prepare a sheet.

Composition of Coating Liquid

Binder Resin (Aekyung A811): 15.0 wt%

Curing agent (Aekyung DN980S): 1.5 wt%

Synthetic Resin Particles (KOLON KS-1000 Silicon Particles): 10.5 wt%

-Synthetic resin particles with red color control function (red): 15.0 wt%

Methyl ethyl ketone: 57.95 wt%

 Example 4

After preparing a transparent polyester film containing 0.001% by weight of a color control material (red), the light diffusion layer using a coating liquid having the following composition on one side of the transparent polyester film prepared as in Example 1 Except for forming, was carried out in the same manner as in Example 1 to prepare a sheet.

Composition of Coating Liquid

Binder Resin (Aekyung A811): 15.0 wt%

Curing agent (Aekyung DN980S): 1.5 wt%

-Synthetic Resin Particle (KOLON KS-1000 Silicon Particle): 25.5 wt%

Methyl ethyl ketone: 58.0 wt%

Comparative Example 1

Except for forming a light diffusion layer using a coating liquid having the following composition on one surface of the same transparent polyester film (Toray Saehan XG-6DF2P, 100㎛) as in Example 1, the same as in Example 1 To prepare a sheet.

Composition of Coating Liquid

Binder Resin (Aekyung A811): 15.0 wt%

Curing agent (Aekyung DN980S): 1.5 wt%

-Synthetic Resin Particle (KOLON KS-1000 Silicon Particle): 25.5 wt%

Methyl ethyl ketone: 58.0 wt%

Experimental Example

The physical properties of the sheets prepared in Examples 1 to 4 and Comparative Example 1 were measured as described in Table 1 below.

Experimental Example 1 Measurement of Thickness of Coating Layer

The coating layer thicknesses of the sheets prepared in Examples 1 to 4 and Comparative Example 1 were measured using a micrometer sedimentation meter [Mitsutoyo Co., Model: ID-Ff125], and the sheet thickness was transparent from the measured value of the total thickness of the sheet. It calculated by subtracting the thickness of the base film.

Experimental Example 2: Haze Measurement

The haze of the sheets prepared in Examples 1 to 4 and Comparative Example 1 was measured using a haze meter (NIPPON DENSHOKU KOGYO Co. Ltd. Model 1000) of Nippon Densoku Co., Ltd., based on ASTM D-1003.

Experimental Example 3: Appearance Confirmation

The sheets prepared in Examples 1 to 4 and Comparative Example 1 were visually inspected for appearance of the coated surface by reflection and transmission under a three-wavelength lamp.

Experimental Example 4: Vertical Luminance Measurement

With respect to the sheets prepared in Examples 1 to 4 and Comparative Example 1, the vertical luminance on the backlight unit assembly was measured using the BM-7 equipment.

Experimental Example 5: Color coordinate measurement

For the sheets prepared in Examples 1 to 4 and Comparative Example 1, the color coordinates of the backlight unit assembly were measured using the BM-7 equipment.

TABLE 1

division Bar Player (No.) Speed (Cm / sec) Haze (%) Exterior judgment Vertical luminance (Cd / m ² ) Color coordinates (x / y) Example 1 12 3 88 Good 4,720 0.2952 / 0.2850 Example 2 12 3 87 Good 4,730 0.3061 / 0.2769 Example 3 12 3 86 Good 4,650 0.3059 / 0.2711 Example 4 12 3 87 Good 4,700 0.3057 / 0.2850 Comparative Example 1 12 3 87 Good 4,720 0.3008 / 0.2875

As shown in Table 1, it can be seen that by using the color adjustable sheet according to the present invention in the backlight unit, it is possible to move the color coordinates of the backlight unit without deteriorating haze and basic luminance properties.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the invention, and such modifications and variations belong to the appended claims.

1 is a cross-sectional view of a light diffusion sheet for a conventional LCD backlight unit.

Figure 2 is a cross-sectional view of the light diffusion sheet for the LCD backlight unit according to an embodiment of the present invention.

3 is a cross-sectional view of a light diffusion sheet for an LCD backlight unit according to another embodiment of the present invention.

Figure 4 is a cross-sectional view of the light diffusion sheet for the LCD backlight unit according to another embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

1: base film 2: resin particles

3: binder resin 4: color control material

5: Color Control Transparent Resin Particles 6: Color Control Material-Containing Substrate Film

Claims (8)

In the sheet for a backlight unit of a liquid crystal display, An LCD backlight unit sheet comprising a transparent polyester base film and a coating layer formed by applying a coating liquid containing a transparent binder resin and transparent resin particles to at least one surface of the base film, A sheet for a backlight unit of a liquid crystal display, comprising a color adjusting component. The method of claim 1, The color control component is a sheet for a backlight unit of a liquid crystal display, characterized in that the color control material mixed in the binder resin of the coating layer. The method of claim 1, The color control component is a color control transparent resin particles contained in the coating layer, the sheet for a backlight unit of the liquid crystal display. The method of claim 1, Wherein the color control component is a color control material contained in the base film, the sheet for a backlight unit of the liquid crystal display. The method according to any one of claims 1 to 4, An antistatic layer is further included on at least one side of the backlight unit sheet of the liquid crystal display, the backlight unit sheet of the liquid crystal display. In the sheet for a backlight unit of a liquid crystal display, Condensing layer formed by applying a transparent polyester base film and a coating liquid containing a transparent binder resin on at least one side of the base film, A sheet for a backlight unit of a liquid crystal display, comprising a color adjusting component. The method of claim 6, And said color control component is a color control material mixed with said binder resin of said light collecting layer. The method of claim 6, Wherein the color control component is a color control material contained in the base film, the sheet for a backlight unit of the liquid crystal display.

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