KR20130027705A

KR20130027705A - Micro lens sheet and lcd including the same, and method of fabricating micro lens sheet

Info

Publication number: KR20130027705A
Application number: KR1020110091080A
Authority: KR
Inventors: 김성훈; 김영웅; 김선웅; 김보라
Original assignee: 엘지디스플레이 주식회사
Priority date: 2011-09-08
Filing date: 2011-09-08
Publication date: 2013-03-18

Abstract

PURPOSE: A micro lens sheet, liquid crystal display device including the same, and a manufacturing method of the sheet are provided to collect partial light while spreading and distributing the partial light by forming a flat portion between dome shape patterns facing each other on the micro lens sheet. CONSTITUTION: A micro lens sheet is placed on the top of a light source. The micro lens sheet includes a micro lens layer(220). A plurality of spreading patterns(230) are formed on a side in which a micro lens layer faces a liquid crystal panel. The spreading patterns are separated from each other. A flat portion(240) is formed between the spreading patterns. A reflecting plate is placed on the bottom of the micro lens sheet.

Description

Micro lens sheet and method for manufacturing liquid crystal display and micro lens sheet including the same {Micro lens sheet and LCD including the same, and method of fabricating Micro lens sheet}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a micro lens sheet capable of realizing high brightness, a light weight and a thin film, and a method of manufacturing a liquid crystal display device and a micro lens sheet with improved display quality and high brightness.

In line with the recent information age, the display field has also been rapidly developed, and a liquid crystal display device (FPD) is a flat panel display device (FPD) having advantages of thinning, light weight, and low power consumption. LCD, plasma display panel device (PDP), electroluminescence display device (ELD), field emission display device (FED), etc. : It is rapidly replacing CRT.

Among them, liquid crystal display devices are used most actively in the field of notebooks, monitors, TVs, etc. because of their excellent contrast ratio and high contrast ratio, and liquid crystal display devices do not have their own light emitting elements. Will be required.

Accordingly, a backlight unit having a light source is provided on a rear surface of the liquid crystal panel to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance.

Meanwhile, a general backlight unit is classified into a side light method and a direct type method according to an arrangement of light sources. The side light method is a structure in which one or a pair of light sources is disposed at one side of the light guide plate. It has, or two or two pairs of light sources have a structure arranged on each side of the light guide plate, the direct type has a structure in which several light sources are arranged under the optical sheet.

Here, the side light method is easier to manufacture than the direct type method, and has the advantages of lighter weight and lower power consumption than the direct type.

1 is a cross-sectional view of a liquid crystal display device using a general side light type backlight unit.

As illustrated, a general liquid crystal display device includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a cover bottom 50, and a top cover 40.

The liquid crystal panel 10 is a part that plays a key role in image expression and is composed of first and second substrates 12 and 14 bonded to each other with a liquid crystal layer interposed therebetween. A printed circuit board (not shown) is connected to each of the two adjacent edges of the liquid crystal panel 10 through a connection member (not shown).

In this case, polarizing plates 19a and 19b for selectively transmitting only specific light are attached to each outer surface of the first second substrates 12 and 14 of the liquid crystal panel 10.

And, the rear of the liquid crystal panel 10 and the LED assembly 29 arranged along the longitudinal direction of at least one side edge of the support main 30, the white or silver reflecting plate 25 seated on the cover bottom 50 and The backlight unit 20 includes a light guide plate 23 mounted on the reflective plate 25 and an optical sheet 21 interposed therebetween.

Here, the LED assembly 29 is composed of a plurality of LEDs 29a and a PCB 29b on which the plurality of LEDs 29a are mounted.

The liquid crystal panel 10 and the backlight unit 20 have a top cover 40 surrounding the top edge of the liquid crystal panel 10 and a back surface of the backlight unit 20 in a state where the edges are surrounded by the support main 30 having a rectangular frame shape. Cover cover 50 to cover each is coupled in front and rear are integrated through the support main 30 as a medium.

Therefore, the light emitted from the LED assembly 29 is incident on the light guide plate 23 and then refracted in the direction of the liquid crystal panel 10. The light emitted from the LED assembly 29 is processed to a high quality of uniform luminance while passing through the optical sheet 21 to the liquid crystal panel 10. Incident, the liquid crystal panel 10 thereby displays an image to the outside.

On the other hand, the liquid crystal display device is a trend that the use area, such as a computer monitor and a wall-mounted television, as well as a portable display device is gradually widening, and research on a thin liquid crystal display device having a large display area has been actively conducted.

However, when a thin liquid crystal display device is to be implemented, a spectral mura or hot band in which light is dispersed appears at a viewing angle in which the luminance distribution changes rapidly.

Such spectral mura and hot band are a factor of degrading the image quality of the liquid crystal display.

Therefore, in order to solve this problem, if the number of optical sheets is increased, the image quality is improved, but the production cost of the backlight unit 20 is increased, and the working process time is increased in the modularization process of the liquid crystal display, thereby decreasing the efficiency of the process. It causes a problem of increasing the manufacturing cost.

In addition, the thinness and the light weight of the liquid crystal display may be inhibited, and in particular, the luminance of the liquid crystal display may be reduced.

The present invention is to solve the above problems, and to provide an optical sheet that can improve the brightness as a first object.

Through this, an object of the present invention is to provide a liquid crystal display device with improved display quality and high brightness while providing light weight and thinness.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a liquid crystal panel; A light source positioned under the liquid crystal panel; A microlens sheet seated on the light source and having a plurality of diffusion patterns formed on one surface facing the liquid crystal panel, wherein the plurality of diffusion patterns are spaced apart from each other to form a flat portion therebetween; And a reflecting plate disposed under the micro lens sheet, wherein the flat portion has a width of 1/2 to 1 of a width of a bottom surface of the plurality of diffusion patterns.

At this time, the height of the plurality of diffusion patterns is 1/3 to 1/2 of the width of the bottom surface of the plurality of diffusion patterns, the plurality of diffusion patterns is one selected from the dome shape, triangular pyramid, square pyramidal.

At least one of a light collecting sheet and a diffusion sheet is positioned between the micro lens sheet and the light source, and the micro lens sheet includes a support layer, and the plurality of diffusion patterns protrude from the support layer.

In addition, the support layer has a haze characteristic, and a diffusion layer is provided on the rear surface of the support layer.

In this case, a light guide plate is formed between the reflective plate and the micro lens sheet, and the light source is arranged on one side or both sides of the light guide plate.

In addition, the present invention and the support layer; It is formed on one surface of the support layer, a plurality of diffusion patterns are formed, the plurality of diffusion patterns include a microlens layer spaced apart from each other to form a flat portion therebetween, the width of the flat portion of the plurality of diffusion patterns Provide a micro lens sheet of 1/2 to 1 of the width of the base.

At this time, the height of the plurality of diffusion patterns is 1/3 to 1/2 of the width of the bottom surface of the plurality of diffusion patterns.

The present invention also provides a micro lens sheet including a resin tank containing a resin, a gravure roll in which a predetermined portion is locked in the tank, and a doctor blade for forming a pattern on the resin on the surface of the gravure roll. A method of manufacturing a micro lens sheet using a manufacturing apparatus, the method comprising: applying the resin to the surface of the gravure roll by rotating the gravure roll; Transferring the resin coated on the surface of the gravure roll to the base film while the base film is moved in one direction to the top of the gravure roll; It provides a micro lens sheet manufacturing method comprising the step of forming a diffusion pattern spaced apart from each other on the resin applied on the base film by controlling the distance between the doctor blade and the base film.

At this time, the distance between the doctor blade and the base film is made through the height adjustment of the doctor blade.

As described above, according to the present invention, a flat portion is formed between the dome-shaped patterns adjacent to each other in the micro lens sheet of the optical sheet, so that the micro lens sheet diffuses and diffuses some light and at the same time collects some light. The effect of dispersing and diffusing light can prevent spectral mura or hot bands in which light is dispersed at the viewing angle at which the luminance distribution changes rapidly. There is.

In addition, there is an effect of providing a high brightness liquid crystal display device through the effect of condensing light.

In addition, by forming the micro lens sheet through the micro gravure (micro gravure), there is an effect that can improve the efficiency of the process compared to the conventional method to take out through the mold having the shape of the pattern.

1 is a cross-sectional view of a liquid crystal display device using a general side light type backlight unit.
2 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.
3 is an exploded perspective view of the liquid crystal panel of FIG. 2;
4 is an exploded perspective view of the backlight unit of FIG. 2;
5 is an enlarged cross-sectional view of the micro lens sheet of FIG. 4;
6 is a cross-sectional view schematically showing a method for manufacturing a micro lens sheet according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

2 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 3 is an exploded perspective view of the liquid crystal panel of FIG. 2.

As shown, the liquid crystal display comprises a liquid crystal panel 110, a backlight unit 120, a support main 130, a cover bottom 150, and a top cover 140.

First, referring to FIG. 3, which is an exploded perspective view of the liquid crystal panel 110, in detail, a plurality of data lines 111b may be disposed on one surface of the first substrate 112 called a lower substrate or an array substrate. ) And the gate line 111a vertically cross each other to define the pixel P. At the intersection of these two lines, a thin film transistor T is provided and connected in a one-to-one correspondence with the transparent pixel electrode 113a provided in each pixel region P.

The second substrate 114 facing the first substrate 112 with the liquid crystal layer 160 interposed therebetween is called an upper substrate or a color filter substrate. A black matrix 118 of a lattice shape covering a pixel region P so as to expose only the pixel electrode 113a while covering the non-display elements such as the gate line 111a, the data line 111b and the thin film transistor T .

A color filter 115 for R (red), G (green), and B (blue), and a transparent common electrode 115 for covering all of the color filters 115, (113b).

First and second polarizing plates 119a and 119b for selectively transmitting only specific light are attached to the outer surfaces of the first second substrates 112 and 114, respectively.

In addition, the gate and the data printed circuit board 117 are connected through at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board, so that the side or the cover of the support main 130 is modularized. It is folded to the back of the bottom 150 is in close contact.

At this time, although not clearly shown in the figure, the upper and lower alignment films for determining the initial alignment direction of the liquid crystal are interposed at the boundary between the two substrates 112 and 114 and the liquid crystal layer 160, A seal pattern (not shown) is formed along the edges of the substrates 112 and 114 to prevent leakage of the liquid crystal layer 160 filled between the substrates 112 and 114.

Therefore, the liquid crystal panel 110 is turned on by the on / off signal of the thin film transistor T which has been transferred to the gate line 111a so that the thin film transistor T selected for each gate line 111a is turned on the image signal of the data line 111b is transmitted to the corresponding pixel electrode 113a and the alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode 113a and the common electrode 113b generated thereby And shows the difference in transmittance.

In addition, the liquid crystal display according to the present invention includes a backlight unit 120 for supplying light from the rear surface of the liquid crystal panel 110 so that a difference in transmittance of the liquid crystal panel 110 is expressed to the outside.

The backlight unit 120 includes an LED assembly 129 arranged along at least one edge length direction of the support main 130, a reflecting plate 125, a light guide plate 123 mounted on the reflecting plate 125, and an upper portion thereof. It includes an optical sheet 121 which is interposed.

The LED assembly 129 is a light source of the backlight unit 120 and is disposed at one side of the light guide plate 123 so as to face the light incident surface of the light guide plate 123. The LED assembly 129 includes a plurality of LEDs 129a, And a PCB 129b on which a plurality of LEDs 129a are mounted with a predetermined spacing.

At this time, the light guide plate 123 evenly spreads the light incident from the LED 129a into the surface of the light guide plate 123 while propagating the light guide plate 123 inside by a plurality of total reflections to provide a surface light source to the liquid crystal panel 110. do.

In addition, the reflector plate 125 is positioned on the rear surface of the light guide plate 123, and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of the light.

The optical sheet 121 on the upper part of the light guide plate 123 includes first and second light collecting sheets 121a and 121b (see FIG. 4) and a micro lens sheet 200 (see FIG. 4).

In particular, the micro lens sheet 200 (refer to FIG. 4) of the present invention refracts and scatters light and simultaneously condenses some light so that a spectral mura or hot band of a liquid crystal display is generated. To improve the brightness at the same time. We will discuss this in more detail later.

In the backlight unit 120, light emitted from the LED 129a is incident into the light guide plate 123 through the light incident part of the light guide plate 123, and the incident light passes through the light guide plate 123 by a plurality of total reflections. While spreading evenly over a wide area of the light guide plate 123, the light is collected and diffused while passing through the optical sheet 121, processed into uniform high-quality light, and then incident to the liquid crystal panel 110.

As a result, the liquid crystal panel 110 finally displays an image.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130, and the cover bottom 150. The top cover 140 has upper and side edges of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover the upper surface of the top cover 140 is opened to display an image implemented in the liquid crystal panel 110.

In addition, the cover bottom 150, on which the liquid crystal panel 110 and the backlight unit 120 are mounted and is a basis for assembling the entire structure of the liquid crystal display device, is formed into a rectangular plate shape with its edge vertically bent at a predetermined height .

A support main 130 having a rectangular frame shape seated on the cover bottom 150 and surrounding the edges of the liquid crystal panel 110 and the backlight unit 120 is combined with the top cover 140 and the cover bottom 150.

The cover main body 130 may be referred to as a guide panel or a main support or a mold frame. The cover main body 130 may be referred to as a bottom cover or a bottom cover, I will.

4 is an exploded perspective view of the backlight unit of FIG. 2, and FIG. 5 is an enlarged cross-sectional view of the microlens sheet of FIG. 4.

As shown, the backlight unit 120 includes a white or silver reflecting plate 125 seated on the cover bottom (150 of FIG. 2), and an LED assembly 129 which is a light source arranged along the longitudinal direction of one edge thereof. The light guide plate 123 mounted on the reflector plate 125 and the optical sheet 121 mounted on the light guide plate 123 are formed.

The LED assembly 129 is located at one side of the light guide plate 123 to face the light incident surface of the light guide plate 123, and the LED assembly 129 has a plurality of LEDs 129a and a plurality of LEDs 129a at regular intervals. It includes a PCB (129b) to be spaced apart.

At this time, the plurality of LEDs 129a include LED chips (not shown) which emit all of the colors of RGB or emit white, and emit white light toward the light incident surface of the light guide plate 123. In addition, the plurality of LEDs 129a emit light having a color of red (R), green (G), and blue (B), respectively, and by lighting the plurality of RGB LEDs (129a) at once, white light by color mixing is generated. It can also be implemented.

In addition to the LED assembly 129, a fluorescent lamp such as a cathode cathode fluorescent lamp or an external electrode fluorescent lamp may be used.

The light guide plate 123 into which the light emitted from the plurality of LEDs 129a is incident is spread evenly to a large area of the light guide plate 123 while the light incident from the LED 129a propagates through the light guide plate 123 by a plurality of total reflections. The surface light source is provided to the liquid crystal panel 110.

Accordingly, the light guide plate 123 may be formed of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials capable of transmitting light, or polycarbonate (PC). It is manufactured in a flat type. The light guide plate 123 is excellent in transparency, weather resistance, and colorability to induce light diffusion when light is transmitted.

In addition, the light guide plate 123 may include a pattern having a specific shape on the rear surface to supply a uniform surface light source. Here, the pattern may be configured in various ways, such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like to guide the light incident into the light guide plate 123. The pattern is formed on the lower surface of the light guide plate 123 by a printing method or an injection method.

The reflector 125 is positioned on the rear surface of the light guide plate 123, and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel (110 of FIG. 2) to improve brightness of the light.

The optical sheet 121 on the upper part of the light guide plate 123 diffuses or condenses the light passing through the light guide plate 123 to enter a more uniform surface light source into the liquid crystal panel 110 of FIG. 2. A light collecting sheet 121a, a second light collecting sheet 121b having a prism pattern, and a micro lens sheet 200 are formed.

Here, each of the first and second light collecting sheets 121a and 121b is arranged adjacent to each other in a band shape so that a plurality of patterns in which a peak and a valley are repeated are arranged in a row to protrude from the support layer. The sheets 121a and 121b are arranged so that the arrangement of each pattern is perpendicular to each other.

Therefore, the first and second light collecting sheets 121a and 121b collect high-brightness light through the liquid crystal panel 110 (refer to FIG. 2) positioned on the first and second light collecting sheets 121a and 121b.

In addition, the micro lens sheet 200 positioned on the second light collecting sheet 121b disperses and diffuses the light collected from the first and second light collecting sheets 121a and 121b, thereby preventing the light from being partially concentrated. Done.

In particular, the microlens sheet 200 of the present invention diffuses and diffuses light, and at the same time, some light is transmitted through the microlens sheet 200 as it is to be collected, thereby improving luminance.

That is, as shown in Figure 5, the micro lens sheet 200 is a polycarbonate (poly carbonate), poly sulfone (poly sulfone), polyacrylate (poly acrylate), polystyrene (poly) that can transmit light Support layer 210 made of styrene series, poly vinyl chloride series, poly vinyl alcohol series, poly norbornene series, polyester series, etc. The upper surface includes a microlens layer 220 for transmitting and scattering light.

Here, the thickness t of the support layer 210 may be 10 to 1000 μm so that the mechanical strength and thermal stability of the micro lens sheet 200, appropriate flexibility and loss of transmitted light are small, and particularly, the thickness t may be formed to be 25 to 600 μm. It is preferable.

The support layer 210 has a haze characteristic. When the light passes through a transparent material, the haze characteristic means that the light is diffused according to the intrinsic properties of the material in addition to reflection or absorption depending on the kind of material, so that an opaque cloudy image is obtained. This haze characteristic value is measured by the following equation (1).

Haze (%) = ({Total Transmission Amount of Light-Straight Light Amount} / {Total Transmission Amount of Light}) × 100 .... Equation (1)

By adjusting the haze value, the desired luminance and viewing angle can be realized. If the haze value is 30% or less, the light diffusion rate is low and the viewing angle is narrowed. You lose.

The haze value of the support layer 210 may be configured to include a diffusion component such as beads 211 or to form a fine pattern (not shown) on the lower surface without including the beads 211.

In this case, the beads 211 may prevent the light from being partially concentrated by dispersing the light incident to the micro lens sheet 200.

In addition, the microlens sheet 200 that does not include the beads 211 has a feature of adjusting the scattering angle of light according to the shape of the fine pattern (not shown), the fine pattern (not shown) is an elliptical pattern ( Elliptical pattern, polygon pattern, etc. can be configured in various ways. By using a hologram pattern, the light incident by the interference pattern is refracted in this asymmetrical direction so that the collected light is more inclined. It can be spread at an angle. Thereby, the light is dispersed to prevent the light from being partially concentrated.

The microlens layer 220 formed on the upper surface of the support layer 210 may be made of the same material as the support layer 210 or may be made of a photosensitive material such as a photoresist, and the microlens layer 220 may be diffused. A plurality of dome-shaped patterns 230, which are patterns, protrude from the support layer 210.

In this case, when the microlens layer 220 is formed of a photosensitive material different from the support layer 210, the refractive index is greater than that of the support layer 210 of the microlens layer 220, or a bead is included therein. It is preferable to have a haze characteristic.

The plurality of dome-shaped patterns 230 are formed in a spherical shape protruding from the support layer 210. Here, the diffusion pattern of the microlens layer 220 may be formed in various ways, such as a triangular pyramid, a square pyramid, in addition to the dome shape.

In this case, the dome-shaped pattern 230 of the present invention is characterized in that the dome-shaped patterns 230 adjacent to each other are positioned to be spaced apart from each other by a predetermined interval.

Accordingly, the flat part 240 is formed between the dome-shaped patterns 230 adjacent to each other.

Accordingly, the microlens sheet 200 of the present invention allows some of the light incident on the microlens sheet 200 to be dispersed and diffused, and at the same time, some of the light is transmitted through the microlens sheet 200 as it is and condensed.

In more detail, the surface of the dome-shaped pattern 230 is divided into a center portion 230a and a refractive portion 230b formed around the center portion 230a.

The central portion 230a transmits some light incident to the micro lens sheet 200 without refraction so that the light is emitted toward the front of the dome-shaped pattern 230.

The refracting portion 230b refracts light on the surface of the dome-shaped pattern 230 according to its incident angle. Therefore, the light refracted by the refracting portion 230b is emitted to the side of the dome-shaped pattern 230. Therefore, light passing through the micro lens sheet 200 is widely dispersed and diffused.

In addition, the microlens sheet 200 of the present invention allows some light incident to the microlens sheet 200 to be transmitted as it is without refraction through the flat portion 240 formed between the dome-shaped patterns 230 adjacent to each other. do.

At this time, the central portion 230a and the flat portion 240 of the dome-shaped pattern 230 allow light to pass through without refraction, thereby concentrating light toward the front of the micro lens sheet 200.

Therefore, the microlens sheet 200 of the present invention diffuses and diffuses some light and at the same time collects some light, thereby spreading light at a viewing angle at which the luminance distribution changes rapidly through the effect of dispersing and diffusing light. It is possible to prevent the occurrence of hot bands in which spectrum mura or contrasting boundaries occur.

In addition, through the effect of condensing light to provide a high brightness liquid crystal display device.

At this time, the height h of the dome-shaped pattern 230 protruding from the support layer 210 is preferably 1/2 or less of the width w of the dome-shaped pattern 230, that is, the dome-shaped pattern ( The height h of 230 is preferably 1/3 to 1/2 of the width w of the bottom surface of the dome-shaped pattern 230 in cross section.

For example, when the diameter D of the dome-shaped pattern 230 is 40 μm, the height h of the dome-shaped pattern 230 may be selected in a range of 13 to 20 μm.

In addition, the separation distance between the dome-shaped patterns 230 adjacent to each other, that is, the width (d, spacing) of the flat part 240 positioned between the dome-shaped patterns 230 adjacent to each other, may correspond to the dome-shaped pattern ( It is preferable that it is 1/2 or more of the width w of 230).

That is, the flat part 240 is preferably 1/2 to 1 of the width w of the bottom surface of the dome-shaped pattern 230 in cross section, that is, the distance between neighboring flat parts 240 is flat. It is equal to or less than twice the width d of 240.

For example, when the width w of the dome-shaped pattern 230 is 40 μm, the width d of the flat portions 240 between the dome-shaped patterns 230 adjacent to each other is in a range of 20 to 40 μm. Can be selected.

On the other hand, in order to further diffuse the light incident to the micro lens sheet 200 on the back surface of the micro lens sheet 200, that is, the backing layer 210, a diffusion layer (not shown) may be further provided. A plurality of fine protrusions (not shown) are formed to protrude from the rear surface of the support layer 210.

Table 1 below is an experimental result of measuring luminance according to the presence of the flat portion 240 between the dome-shaped patterns 230 adjacent to each other and the height h of the dome-shaped pattern 230.

Sample 1 Sample 2 Sample 3 Is there a flat part? No Yes Yes Dome-shaped pattern diameter (D) 30 μm 30 μm 30 μm The height of the dome-shaped pattern (h) 29.02 μm 17 μm 12.11㎛ Luminance (nit, luminance ratio) 369 (98.4%) 406 (108.3%) 409 (108.9%)

Prior to the description, Table 1 shows a first light collecting sheet 121a having a lenticular pattern formed on the light guide plate 123 and a second light collecting sheet having a prism pattern perpendicular to an array of the lenticular patterns of the first light collecting sheet 121a. After placing the microlens sheet 200 having different conditions on the upper portion 121b, the luminance of the light passing through the microlens sheet 200 was measured.

Referring to Table (1), it can be seen that the luminance of Sample 2 is higher than that of Sample 1, which is a flat portion 240 between the dome-shaped pattern 230 of the micro lens sheet 200. When the height h of the dome-shaped pattern 230 is formed to correspond to about 1/2 of the width w of the dome-shaped pattern 230, the luminance may be further improved.

In particular, it can be seen that the luminance of the sample 3 is higher than that of the sample 2, which means that the height h of the dome-shaped pattern 230 is less than 1/2 of the width w of the dome-shaped pattern 230. It can be seen that the brightness is further improved when formed.

Therefore, the microlens sheet 200 of the present invention improves the luminance of light passing through the microlens sheet 200 by forming the flat portion 240 between the dome-shaped patterns 230 adjacent to each other. In particular, by forming the height h of the dome-shaped pattern 230 to be smaller than 1/2 of the width w of the dome-shaped pattern 230, the luminance is further improved.

Hereinafter, a manufacturing method of the micro lens sheet 200 which is a characteristic configuration of the present invention will be described.

The microlens sheet 200 according to the embodiment of the present invention is manufactured by a roll to roll method using a roll plate. In particular, the microlens sheet 200 according to the embodiment of the present invention is microgravure. It is characterized by forming using (micro gravure). This not only enables mass production but also has a low production cost.

6 is a cross-sectional view schematically showing a method of manufacturing a micro lens sheet according to an embodiment of the present invention.

As shown, the manufacturing apparatus of the micro-lens sheet (200 of FIG. 5) is a gravure roll 310 (gravure roll: 310) that is largely locked by rotating a portion of the tank 320 and the tank 320 containing the resin 330, And it is composed of a doctor blade (doctor blade: 340) for forming a pattern on the resin 330 on the surface of the gravure roll (310).

Looking at this in more detail, the gravure roll 310 is disposed in the center of the upper portion of the tank 320 containing the resin 330 is rotatable. At this time, although the gravure roll 310 is shown to rotate in the counterclockwise direction, the gravure roll 310 may be rotated in the clockwise direction.

In addition, first and second guide rolls 360a and 360b which guide the movement of the base film 350 forming the support layer 210 of FIG. 5 on the micro lens sheet 200 of FIG. ) Is installed. At this time, it is preferable that the first and second guide rolls 360a and 360b rotate opposite to the rotation direction of the gravure roll 310.

At this time, the resin 330 contained in the water tank 320 is polycarbonate (polycarbonate), poly sulfone (poly sulfone), polyacrylate (poly acrylate), polystyrene (poly styrene), polyvinyl chloride (poly It may be made of any one of photosensitive materials such as vinyl chloride series, poly vinyl alcohol series, poly norbornene series, polyester series, photoresist.

Therefore, in the process of moving the base film 350 in one direction by the first and second guide rolls 360a and 360b, the gravure roll 310 is positioned between the first and second guide rolls 360a and 360b. Resin 330 is applied on the base film 350 through the).

That is, when a part of the gravure roll 310 is rotated while being locked in the resin 330 in the water tank 320, the resin 330 is applied to the surface of the gravure roll 310 by the rotation of the gravure roll 310. Done.

The resin 330 coated on the surface of the gravure roll 310 is in contact with the surface of the base film 350 moving in one direction through the first and second guide rolls 360a and 360b, and the base film 350 Is transferred onto

The resin 330 transferred to the base film 350 forms a plurality of dome-shaped patterns 230 through height adjustment of the doctor blade 340.

That is, in order to form convex portions of the plurality of dome-shaped patterns 230, the doctor blade 340 is positioned to have a first distance from the base film 350, and the dome-shaped pattern 210 of FIG. In order to form the edge portion and the flat portion 240, the doctor blade 340 is positioned to have a second distance shorter than the first distance from the base film 350.

That is, the doctor blade 340 cuts a specific portion of the resin 330 applied to the base film 350 according to the shape to be formed, thereby forming a microlens layer formed of a plurality of dome patterns 230 (FIG. 5). 220).

Accordingly, the present invention improves the efficiency of the process compared to the conventional method of taking out a mold (not shown) having a pattern shape by forming a micro lens sheet (200 of FIG. 5) through micro gravure. You can.

That is, the existing mold method is formed by pressing a mold mold (not shown) in which the shape of the pattern to be formed is formed on the resin 330 applied on the base film 350. Si) In order to increase the process cost according to the production and to apply to various models, a separate mold mold (not shown) corresponding to the shape and size of the various patterns has to be provided, and thus, the efficiency of the process is low.

In contrast, the present invention forms a microlens sheet (200 in FIG. 5) through a roll to roll method and simultaneously forms a microlens layer (220 in FIG. 5) through microgravure, thereby forming a separate mold. The mold (not shown) can be deleted, thereby preventing the process cost from increasing, and by controlling the height of the doctor blade 340, a desired pattern 230 can be formed, thereby improving the efficiency of the process. You can.

As described above, in the liquid crystal display of the present invention, the microlens sheet (FIG. 5) is formed by forming the flat portion 240 between the dome-shaped patterns 230 in which the microlens sheet 200 (in FIG. 5) is adjacent to each other. It is to improve the brightness of the light passing through 200 of the, in particular, the height of the dome-shaped pattern 230 (h of FIG. 5) 1/2 of the diameter (D of FIG. 5) of the dome-shaped pattern 230 By forming smaller than that, the luminance is further improved.

Therefore, the microlens sheet 200 of FIG. 5 disperses and diffuses some light while condensing some light, and thus light is collected at a viewing angle at which the luminance distribution changes rapidly through the effect of dispersing and diffusing light. It is possible to prevent the occurrence of scattered spectrum mura or hot bands in which boundaries of light and shade occur.

In particular, the present invention by forming a micro lens sheet (200 in Figure 5) through a micro gravure (micro gravure), thereby improving the efficiency of the process compared to the conventional method of taking out through a mold having a pattern shape (not shown) You can.

Meanwhile, in the above description and the accompanying drawings, the LED assembly (129 of FIG. 4) has been described as a side light method located at one side of the light guide plate (123 of FIG. 4). A direct type for arranging a plurality of LED assemblies (129 of FIG. 4) side by side is also possible. In this case, the light guide plate (123 of FIG. 4) may be omitted.

In addition, a diffusion sheet (not shown) may be further disposed below the first light collecting sheet 121a of FIG. 4, and any one of the first and second light collecting sheets 121a and 121b of FIG. 4 may be deleted. It is also possible. That is, the configuration of the optical sheet 121 of FIG. 4 may be variously changed as long as the microlens sheet 200 according to the embodiment of the present invention is positioned at the top.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

200: Micro Lens Sheet
210: support layer, 211: bead
220: microlens layer, 230: dome pattern (230a: center portion, 230b: refractive portion)

Claims

A liquid crystal panel;
A light source positioned under the liquid crystal panel;
A microlens sheet seated on the light source and having a plurality of diffusion patterns formed on one surface facing the liquid crystal panel, wherein the plurality of diffusion patterns are spaced apart from each other to form a flat portion therebetween;
Reflector located under the micro lens sheet
And a flat portion having a width of 1/2 to 1 of a width of a bottom surface of the plurality of diffusion patterns.

The method of claim 1,
The height of the plurality of diffusion patterns is 1/3 to 1/2 of the width of the bottom surface of the plurality of diffusion patterns.

The method of claim 1,
The plurality of diffusion patterns is one selected from a dome shape, a triangular pyramid shape, and a square pyramid shape.

The method of claim 1,
And at least one of a light collecting sheet and a diffusion sheet between the micro lens sheet and the light source.

The method of claim 1,
The micro lens sheet includes a support layer, and the plurality of diffusion patterns protrude from the support layer.

The method of claim 5, wherein
The support layer has a haze characteristic liquid crystal display device.

The method of claim 5, wherein
And a diffusion layer disposed on a rear surface of the support layer.

The method of claim 1,
And a light guide plate between the reflective plate and the micro lens sheet, wherein the light source is arranged on one side or both sides of the light guide plate.

A support layer;
It is formed on one surface of the support layer, a plurality of diffusion patterns are formed, the plurality of diffusion patterns are spaced apart from each other microlens layer having a flat portion formed therebetween
/ RTI >
The width of the flat portion is a micro lens sheet of 1/2 ~ 1 of the width of the bottom of the plurality of diffusion patterns.

The method of claim 9,
The height of the plurality of diffusion patterns is a micro lens sheet of 1/3 to 1/2 of the width of the bottom of the plurality of diffusion patterns.

Micro-lens sheet manufacturing apparatus including a tank containing a resin, a gravure roll that rotates by locking a portion of the tank, and a doctor blade which forms a pattern on the resin on the surface of the gravure roll. In the lens sheet manufacturing method,
Applying the resin to the surface of the gravure roll by rotating the gravure roll;
Transferring the resin coated on the surface of the gravure roll to the base film while the base film is moved in one direction to the top of the gravure roll;
Forming a diffusion pattern spaced apart from each other on the resin coated on the base film by controlling a distance between the doctor blade and the base film;
Micro lens sheet manufacturing method comprising a.

The method of claim 11,
The distance between the doctor blade and the base film is made through the height adjustment of the doctor blade micro lens sheet manufacturing method.