KR20110086445A - Microlens film and lcd comprising the same - Google Patents

Abstract

PURPOSE: A micro-lens film and an LCD(Liquid Crystal Display) including the same are provided to obtain a clear image by inducing the uniform light diffusion through passing through the light researched from the light source lamp locating in the side or the back side. CONSTITUTION: A micro-lens film is a transparent substrate and a plurality of micro-lens patterns located in the transparent substrate. A micro-lens pattern layer comprises a plurality of micro-lens patterns in which the upper side is sphere or ellipse. A blocking prevention layer(4) is located in the rear side of the transparent substrate. A plurality of micro-lens patterns comprises a body portion(2) in which the light flows in and a protrusion. The protrusion formed in the body portion is circle or oval in shape.

Description

Microlens film and liquid crystal display including the same {MICROLENS FILM AND LCD COMPRISING THE SAME}

The present invention relates to a microlens film and a liquid crystal display device including the same, and more particularly, to an optical film used in a thin film transistor liquid crystal display (TFT-LCD), a light source lamp positioned at a side or a rear side of a display to obtain a clear image of a display. The present invention relates to a microlens film and a liquid crystal display including the same, which induce uniform light diffusion while passing light irradiated therefrom to obtain a clear optical image.

In general, unlike the other flat panel display methods, the liquid crystal display is a non-light emitting material, and thus, an additional light emitting device is required to improve the brightness of the display screen.

Such light emitting devices include a front light method, a backlight method, and the like, of which a light source from the light source of the backlight unit attached to the rear of the display element is led to the opposite side through the light guide plate, and the metal deposition plate or the opaque white plate. It is an indirect lighting method that improves the brightness of the display screen by reflecting the reflector such that the light is emitted to the front. In such a backlight method, it is necessary to realize maximum image brightness with minimum power consumption.

On the other hand, the most important characteristics that an optical film having a function of uniformly diffusing while passing through the diffuser or light guide plate irradiated from the light source lamp without loss are high total light transmittance and high haze (HAZE). A further required property on the basis of such optical properties is high light efficiency, i.e., high brightness, which changes the distribution of light and the path of light uniformly formed in the light source to the front light required for the liquid crystal display. Conventional manufacturing methods for such optical films include a method of applying a composition composed of a binder resin and spherical particles on a substrate, and an imprint method of transferring a spherical pattern to a substrate or a resin layer of the substrate.

However, the surface shape formed in the above manner has a high efficiency optical path required for the optical film, that is, high brightness due to the low aspect ratio between the body portion into which light is introduced and the protrusion formed by particles or patterns. There is a problem that cannot be achieved.

The present invention has been made to solve the above problems, an object of the present invention is an optical film used for a thin film transistor liquid crystal display (TFT-LCD) from the light source lamp located on the side or rear to obtain a clear image of the display The present invention provides a microlens film and a liquid crystal display including the same, which can induce uniform light diffusion while passing light irradiated to obtain a clear light image.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The object is a microlens pattern layer having a transparent substrate and a plurality of microlens patterns positioned on the transparent substrate, the microlens pattern layer having a plurality of microlens pattern having a spherical or elliptical shape at the top thereof, and a blocking located at the rear surface of the transparent substrate. A plurality of microlenses pattern comprising a prevention layer, the body portion to which light is introduced and a spherical or elliptical protrusion formed on the body portion, achieved by the microlens film, characterized in that it comprises a protrusion coated with a coating portion do.

Here, the aspect ratio of the protrusions coated with the body portion and the coating portion is 0.8 to 1.5.

Preferably, the diameter of the body portion of the microlens pattern is 10nm to 100㎛.

Preferably, the microlens pattern is characterized in that it comprises an ultraviolet curable resin or a thermosetting resin.

In addition, the object is achieved by a backlight assembly and a liquid crystal display device comprising the microlens film.

According to the present invention, an optical film used in a thin film transistor liquid crystal display (TFT-LCD) to induce uniform light diffusion while passing light emitted from a light source lamp located on the side or the back to obtain a clear image of the display It has the effect of obtaining an image.

1 is a cross-sectional view of a microlens film according to the present invention.
2 is a cross-sectional view of a conventional unit microlens.
3 is a unit microlens sectional view of a microlens film according to the present invention;
Figure 4 is a microlens cross-sectional view defining an aspect ratio of a microlens film according to the present invention.
5 is a SEM photograph of a microlens film according to an embodiment of the present invention.
6 is a SEM photograph of a microlens film according to a conventional comparative example.

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. .

The microlens film according to the present invention is a transparent substrate and a plurality of microlens patterns positioned on the transparent substrate, the microlens pattern layer having a plurality of microlens pattern having an upper surface of a spherical shape or an oval shape and a back surface of the transparent substrate. It consists of a blocking prevention layer located in the. The plurality of microlens pattern includes a body portion to which light is introduced and a spherical or elliptical protrusion formed on the body portion, and includes a protrusion coated with a coating portion.

In addition, the microlens film according to the present invention is characterized in that the aspect ratio (ASPECT) ratio of the body portion and the coating portion coated protrusion, that is, the height of the coating portion coated protrusion relative to the radius of the body portion is 0.8 to 1.5. In the present invention, the "coating part coated with a coating part" is applied in determining an aspect ratio, but the "projection part" without the coating part may be applied. The spherical or elliptical shape of the surface having such an ASPECT ratio of 0.8 or more can be expected to increase the brightness of the microlens film. The ASPECT ratio, which can be expected to increase in brightness, is preferably 0.8 or more, and particularly preferably 0.8 to 1.5. When the ASPECT ratio is less than 0.8, the light condensation of light is lowered. This is because a decrease occurs.

Since the base sheet of the microlens film according to the present invention needs to transmit light, it is formed of transparent, especially colorless transparent synthetic resin. The synthetic resin used in such a base sheet is not particularly limited, and examples thereof include polyethylene terephthalate, polyethylene naphthalate, acrylic resin, polycarbonate, polystyrene, polyolefin, cellulose acetate and the like. The thickness of the base sheet is about 10 ~ 500㎛, preferably about 75 ~ 250㎛. If the thickness of the base sheet does not satisfy the lower limit of the above range, CURL is likely to occur due to the resin composition forming the microlens pattern layer, and if the thickness of the base sheet is outside the upper limit of the above range, the liquid crystal display device This is because the luminance may decrease, and the thickness of the backlight unit becomes large, which is against the demand for thinning of the liquid crystal display device.

In addition, the microlens pattern layer of the microlens film according to the present invention can be implemented by a imprint method, and as the polymer used in the resin of the imprint method, an ultraviolet curable resin may be used, for example, a urea resin or a melamine resin. , Phenol resins, epoxy resins, unsaturated polyester resins, alkyd resins, urethane resins, acrylic resins, polyurethanes, fluorine resins, silicone resins, polyamideimide and the like. Moreover, in addition to the said polymer, resin may be mix | blended with resin, for example, a plasticizer, a stabilizer, a deterioration inhibitor, a dispersing agent, an antifoamer, a foaming agent, etc., for example. Since resin needs to transmit light, it is transparent and it is especially preferable that it is colorless and transparent.

In addition, the diameter of the microlenses is preferably 0.1 to 100 µm, particularly preferably about 20 to 70 µm. If the diameter of the lens is less than the lower limit of the above range, the light diffusing effect is insufficient. On the contrary, if the diameter is outside the upper limit of the above range, the thickness of the optical sheet becomes thicker, so that the thickness of the entire backlight unit becomes larger and the thickness of the liquid crystal display device becomes thinner. Because it is against the demands of. In addition, the diameter of the body portion of the microlens pattern is preferably 10nm to 100㎛.

In addition, the microlens pattern layer of the present invention may be composed of a resin and particles dispersed in the resin. As the polymer used for the resin, any of the curable resins can be used. However, in consideration of ease of handling and availability, a thermosetting resin or the like can be suitably used in the present invention. As such thermosetting resins, for example, urea resin, melamine resin, phenol resin, epoxy resin, unsaturated polyester resin, alkyd resin, urethane resin, acrylic resin, polyurethane, fluorine resin, silicone resin, polyamideimide, etc. Can be enumerated. Moreover, in addition to the said polymer, resin may be mix | blended with resin, for example, a plasticizer, a stabilizer, a deterioration inhibitor, a dispersing agent, an antifoamer, a foaming agent, etc., for example. Since resin needs to transmit light, it is transparent and it is especially preferable that it is colorless and transparent.

The particles may be spherical or non-spherical particles, and examples thereof include acrylic resins, polyurethanes, polyvinyl chlorides, polystyrenes, polyacrylonitriles, polyamides, and polymethylmethacrylates. . The particles are preferably transparent in order to increase the amount of light passing through the microlens film, and in particular, colorless transparent is preferable. The particle diameter of the particles is preferably 0.1 to 100 µm, particularly preferably about 20 to 70 µm. If the particle diameter of the particles does not fall below the lower limit of the above range, the light diffusing effect is insufficient. On the contrary, if the particle diameter is outside the upper limit of the above range, coating of the resin composition forming the light diffusion layer becomes difficult and the particles fall off after lamination. Undesirable results occur.

In addition, in order to manufacture an optical sheet having the desired optical properties, it is important to adjust the resin and particle ratio. Particularly, in order to manufacture an optical sheet having a light transmittance of 85 to 95%, the ratio of particles to 100 parts by weight of the polymer in the resin The amount of this 0.1-1000 weight part is preferable, and the quantity of about 10-500 weight part is especially preferable. When the compounding quantity of particle | grains does not reach the lower limit of the said range, a light-diffusion effect will become inadequate, On the contrary, when a compounding quantity exceeds the upper limit of the said range, application | coating of the resin composition which forms a microlens pattern layer will become difficult. In addition, in order to control the light transmittance, the thickness of the coating layer must be adjusted. In order to obtain a total light transmittance of 85 to 95%, the thickness of the coating layer is preferably between 0.2 and 500 µm (more preferably, 2 to 200 µm). . If the coating thickness is less than the lower limit of the above range, the adhesive strength with the film during coating is lowered and the particles fall off after lamination. When the upper limit of the above range is exceeded, the total light transmittance becomes 84% or less, and thus the desired microlens film cannot be manufactured.

The anti-blocking layer of the microlens film according to the present invention is composed of an anti-blocking layer resin and particles of an anti-blocking layer, and as the polymer used for the anti-blocking layer resin, any of the curable resins can be applied, but considering ease of handling and obtaining. Lower surface thermosetting resin etc. can be used suitably in this invention. As such thermosetting resins, for example, urea resin, melamine resin, phenol resin, epoxy resin, unsaturated polyester resin, alkyd resin, urethane resin, acrylic resin, polyurethane, fluorine resin, silicone resin, polyamideimide, etc. Can be enumerated. Moreover, in addition to the said polymer, you may mix | blend a blocking agent layer resin with a plasticizer, a stabilizer, a deterioration inhibitor, a dispersing agent, an antifoamer, a foaming agent WAX agent, an antistatic agent, etc., for example. Since the blocking prevention layer resin needs to transmit light, it becomes transparent, and it is especially preferable that it is colorless and transparent.

The anti-blocking layer particles used for the anti-blocking layer are substantially spherical anti-blocking layer particles, and examples of the material include acrylic resins, polyurethanes, polyvinyl chlorides, polystyrenes, polyacrylonitriles, polyamides, and polymethylmethacryl. Rates and the like can be enumerated. The antiblocking layer particles are preferably transparent in order to increase the amount of light that passes through the microlens film, and in particular, it is preferable that they are colorless and transparent.

In addition, the particle size of the anti-blocking layer particles used for the anti-blocking layer is preferably 0.1 to 100 µm, particularly preferably about 1 to 50 µm. If the particle size of the anti-blocking layer particles does not fall below the lower limit of the above range, a blocking phenomenon may occur that impairs the film runability during the process. On the contrary, if the particle size is outside the upper limit of the above range, coating of the resin composition forming the anti-blocking layer is difficult. This is because dropping of particles occurs after lamination. In addition, the amount of the antiblocking layer particles used in the antiblocking layer is preferably 0.01 to 500 parts by weight, particularly preferably about 0.1 to 100 parts by weight relative to 100 parts by weight of the polymer in the antiblocking layer resin used for the antiblocking layer.

In addition, the coating portion formed on the protrusion of the microlens pattern of the microlens film according to the present invention after the microlens pattern is formed by the particle coating method or the imprint method on the base film, the knives coating method, gravure transfer coating method, Slot die It is formed through a conventional wet coating method such as a coating method, a comma coating method, a reverse roll coating method, and any coating such as a thermosetting resin or an ultraviolet curable resin may be applied as long as it is a curable resin.

Hereinafter, although this invention is demonstrated in more detail based on the following Example, this invention is not limited by the following Example.

[ Example ]

A microlens pattern mold having a diameter of 54 µm and a height of 27 µm is formed by laser processing on a metal plate. After applying the coating liquid having the composition ratio of Table 1 to the pattern shape of the molded pattern mold using a Mayer bar, a highly transparent polyester film (XG533-100 μm) having a blocking prevention layer was formed. It adhere | attaches on the said coating surface, hardens by ultraviolet irradiation, and produces a microlens pattern film. Coating and curing the coating liquid having the composition ratio of the following Table 1 on the produced microlens film using a Mayer bar (Mayer bar) to coat the coating as shown in the surface shape 1 of Table 3 (see SEM picture in Figure 5) The microlens film with the formed protrusion was prepared. The anti-blocking layer is formed by applying a composition composed of 3 wt% of PMMA, 40 wt% of acrylic resin, and 57 wt% of toluene to a polyester film using a Mayer bar and drying at 100 ° C. for 5 minutes.

Furtherance Detail 100 g Suzy UC3460 (Aekyung Chemistry) 95 g Photopolymerization initiator IRGACURE184 (Shiba) 5 g

[ Comparative example ]

A microlens pattern mold having a diameter of 54 µm and a height of 27 µm is formed by laser processing on a metal plate. After applying the coating liquid having the composition ratio of the following Table 2 to the pattern shape of the molded pattern mold using a Mayer bar, a highly transparent polyester film (XG533-100 µm) having a blocking prevention layer was formed. It adhered to the coated surface, and cured by ultraviolet irradiation to produce a microlens pattern film to prepare a microlens film as shown in the surface shape 2 of Table 3 (see SEM photograph of Figure 6) below. The anti-blocking layer is formed by applying a composition consisting of 3wt% PMMA, 3wt% acrylic resin, and 40wt% acrylic resin and 57wt% toluene on a polyester film using Mayer bar and drying at 100 ° C. for 5 minutes.

Furtherance Detail 100 g Suzy UC3460 (Aekyung Chemistry) 99 g Photopolymerization initiator IRGACURE184 (Shiba) 10g

division Radius of the body part (L) Thickness of protrusions (D) ASPECT ratio Surface shape 1 27.2 μm 29.5 μm 1.084 Surface shape 2 27.2 μm 20 μm 0.735

Using the microlens film according to the Example and Comparative Example was evaluated through the following experimental example, the physical properties are shown in Table 4 to measure the physical properties.

[ Experimental Example ]

1. Measurement of luminance

Measuring equipment: Topcon BM-7

Measurement Method: Average of 9 Measurements

2. Light rays  Transmittance and Haze  Measure

A polyester film sampled at 10 cm x 10 cm was placed vertically in an automatic measuring device (AUTOMATIC DIGITAL HAZEMETER, Nippon Densoku Co., Ltd.), and the value shown by transmitting light having a wavelength of 550 nm in the direction perpendicular to the vertically placed sample was measured. Measured.

At this time, the haze value is calculated by the following equation and displayed on the haze meter.

Haze (%) = (1- P / TT) * 100

The total light transmittance value is also calculated by the following equation and displayed on the meter.

Total light transmittance (%) = (TT / IT) * 100

Where the parameters in the equation are as follows.

P: amount of straight light

TT: total transmittance of light

IT: incident light

3. ASPECT ratio measurement

As can be seen from FIG. 4, which is a microlens cross-sectional view defining an aspect ratio of the microlens film according to the present invention, “L” represents 1/2 of the length of the body portion of the microlens pattern layer and “D”. Denotes the height of the protrusion on which the coating of the microlens pattern layer is coated. The cross section of the microlens film was cut and measured through SEM measurement. ASPECT ratio is the value of D value ratio to L value.

division Total light transmittance (%) HAZE (%) Luminance (cd / ㎡) Example 64 81 6,600 Comparative example 68 80 5,000

As can be seen in Table 4, it can be seen that the microlens film of the surface shape with improved ASP ratio as in the embodiment according to the present invention is much higher in brightness than the conventional micromicrolens film (comparative example).

In the shape of the microlens pattern of the present invention, a microlens film having an ASPECT ratio of 0.8 to 1.5 of a body portion into which light is introduced and a spherical or elliptical protrusion having a predetermined thickness on the body portion has a very high luminance and a thin film transistor liquid crystal display ( It can be used as an optical material for improving the light efficiency of the backlight unit of the TFT-LCD).

1: Microlens Film 2: Base Sheet
3: microlens layer 4: anti-blocking layer
5: microlens layer before coating
6: microlens layer after coating
7: coating on microlens layer

Claims (6)

In microlens film,
With a transparent base material,
A plurality of microlens patterns positioned on the transparent substrate, the microlens pattern layer having a plurality of microlens patterns having a spherical or oval shape on an upper surface thereof;
Including a blocking prevention layer located on the back of the transparent substrate,
The plurality of microlens patterns are a body portion to which light is introduced and a spherical or elliptical protrusion formed on the body portion, characterized in that it comprises a protrusion coated with a coating. The method of claim 1,
An aspect ratio of the projecting portion coated with the body portion and the coating portion is 0.8 to 1.5, the microlens film. The method of claim 1,
The diameter of the body portion of the microlens pattern, characterized in that 10nm to 100㎛, microlens film. The method of claim 1,
The microlens pattern is characterized in that it comprises an ultraviolet curable resin or a thermosetting resin, microlens film. A backlight assembly, characterized in that it comprises a microlens film according to any one of claims 1 to 4. A liquid crystal display device comprising the microlens film according to any one of claims 1 to 4.

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