KR20120041509A - Light condensing sheet for liquid crystal display device and method of fabricating the same - Google Patents

Abstract

PURPOSE: A light concentrating sheet for a liquid crystal display device and a manufacturing method thereof are provided to reduce spectrum mura and hot band phenomena without a separate optical sheet. CONSTITUTION: A light source(129a) is located in a lower part of a liquid crystal panel. A light concentrating sheet(200) is placed on the light source. A light concentrating layer is formed on one side where the light concentrating sheet faces the liquid crystal panel. A plurality of patterns are formed on the light concentrating layer. An adhesive bead(220) is applied onto an upper part of the light concentrating layer. A reflecting plate(125) is located in a lower part of the light concentrating sheet.

Description

Light condensing sheet for liquid crystal display device and method of fabricating the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a light collecting sheet having improved appearance problems in a single product or a combination.

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, LCDs are excellent in moving image display and are most actively used in notebooks, monitors, TVs, etc. due to high contrast ratio. The LCDs are devices that do not have their own light emitting elements. It requires a light source.

Accordingly, a backlight unit having a light source is provided on a rear side of the backlight unit 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 an exploded perspective view of a side light type backlight unit, and FIGS. 2A to 2B and 3A to 3B are photographs showing a conventional problem.

As shown in FIG. 1, the general backlight unit 20 includes a lamp 29a which is a light source, a light guide plate 23 having at least one side surface facing the lamp 29a, and positioned on the same plane as the lamp 29a. (23) It consists of an optical sheet 21 seated on the top.

Further, a reflector 25 for reflecting light exiting to the lower surface of the light guide plate 23 is further formed below the light guide plate 23, and a lamp guide 29b for guiding the lamp 29a is further provided.

Here, the optical sheet 21 is composed of a diffusion sheet 21a, a light collecting sheet 21b, and a protective sheet 21c. The light collecting sheet 21b may be used in one sheet, but in order to implement high brightness, The light condensing sheet 21b of a sheet can be used overlapping.

The light collecting sheet 21b refracts light incident through the diffusion sheet 21a to condense light onto a plane of the liquid crystal display panel (not shown). The light condensing sheet 21b is arranged adjacent to the strip in the longitudinal direction of the light condensing sheet 21b so that a plurality of prism mountains 27 are formed to protrude.

Therefore, as a method for protecting the prism acid 27 of the light collecting sheet 21b or diffusing the collected light, it is essential that the protective sheet 21c is disposed on the light collecting sheet 21b.

That is, the protective sheet 21c is stacked on the light collecting sheet 21b to prevent the prism acid 27 of the light collecting sheet 21b from being damaged by contact with an external object.

On the other hand, the light passing through the light collecting sheet 21b has a portion where the luminance distribution is rapidly changed according to the viewing angle. Due to such optical characteristics, the light collecting sheet 21b is used at a viewing angle at which the luminance distribution changes rapidly. The so-called spectrum mura as shown in FIG. 2A or the hot band where the boundary of light and shade appear as shown in FIG. 2B is shown in which light is dispersed.

Such spectral mura and hot band are a factor of degrading the image quality of the liquid crystal display. In order to solve this problem, a plurality of optical sheets are further stacked on the light collecting sheet 21b to improve image quality.

However, as the number of optical sheets stacked including the protective sheet 21c for the protection of the prism acid 27 increases, the image quality is improved, but the production cost of the backlight unit 20 is increased, In the modular process, the working process time is increased and the efficiency of the process is lowered, which causes a problem of increasing the manufacturing cost.

In particular, despite efforts to manufacture a liquid crystal display device in a light weight and thin form, as the components of the backlight unit 20 which have the greatest influence on the overall thickness of the liquid crystal display device become too large, Lightweight is hindered.

In addition, the light collecting sheet 21b may cause damage to the surface of the prism acid 27 even when the backlight unit 20 is modularized. In this case, protection by the protective sheet 21c is meaningless and defects are immediately produced. It will lead to badness.

In addition, the light collecting sheet 21b has a surface area in contact with the sheet adjacent to the prism acid 27, which causes a problem of a wet-out phenomenon as shown in FIGS. 3A to 3B. Here, the wet-out phenomenon refers to a phenomenon in which two surfaces are in optical contact with each other and the contact portion is visually recognized. This tends to be better recognized when moisture penetrates into the liquid crystal display module, especially under conditions of high air humidity.

This also becomes a factor of lowering the image quality of the liquid crystal display device.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a light collecting sheet capable of preventing damage to a prism acid.

Accordingly, the second object of the present invention is to improve the image quality of the backlight unit, to prevent spectral mura, hot band, and wet-out phenomenon, and to achieve high quality of uniform luminance through the display screen of the liquid crystal display device.

In addition, a third object of the present invention is to reduce the assembly time and the material cost in the modularization process of the liquid crystal display device while realizing the light weight and thinness of the liquid crystal display device.

In order to achieve the above object, the present invention is a liquid crystal panel; A light source positioned under the liquid crystal panel; A light collecting sheet seated on an upper part of the light source, and having a light collecting layer having a plurality of patterns formed on one surface thereof facing the liquid crystal panel, and having adhesive beads coated on the light collecting layer; Provided is a liquid crystal display including a reflector disposed under the light collecting sheet.

In this case, the adhesive bead is a diffusion bead, has a tackiness below the glass transition temperature (Tg), the adhesive bead acrylic resin (urryl resin), urethane resin (urethane resin) and polyester resin (polyesters resin), epoxy It is made of one selected from an acrylate resin (epoxy acrylate resin), urethane acrylate resin (urethane acrylate resin) and silicone acrylate resin (silicone acrylate resin).

The adhesive bead is positioned between the light collecting layers adjacent to each other and protrudes relative to the pattern, and the light collecting sheet includes a support layer made of PMMA (polymethylmethacrylate), PET (polyethylene terephthalate), and the like. The light collecting layer has a dome-shaped lenticular lens or prism acid pattern protruding from the support layer.

In addition, a diffusion layer having a haze component is formed on the other side of the support layer on the opposite side of the one surface on which the light collecting layer is formed, and the light source includes a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp ) And a light emitting diode (LED).

In addition, a light guide plate is formed on the reflective plate, 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; A light collecting layer formed on one surface of the support layer and protruding so that a plurality of patterns are arranged adjacent to each other on the support layer; Provided is a light collecting sheet for a liquid crystal display device including adhesive beads applied on top of the patterns adjacent to each other of the light collecting layer.

Here, the adhesive bead is a diffusion bead, has a tackiness below the glass transition temperature (Tg), the adhesive bead is acrylic resin (urryl resin), urethane resin (urethane resin), polyester resin (polyesters resin), epoxy It is made of one selected from an acrylate resin (epoxy acrylate resin), urethane acrylate resin (urethane acrylate resin) and silicone acrylate resin (silicone acrylate resin).

In addition, the adhesive bead is positioned between the adjacent patterns, and protrudes compared to the pattern.

In addition, the present invention comprises the steps of dropping the resin layer on one surface of the support layer; Pressing the resin layer with a roller to form a pattern in which an acid and a valley are alternated; It provides a manufacturing method of a light collecting sheet for a liquid crystal display device comprising the step of applying a bead having an adhesive on the upper portion of the pattern.

Here, the beads are tacky at a temperature below the glass transition temperature (Tg), and before the resin layer is dropped on one surface of the support layer, forming a diffusion layer on the other surface of the support layer.

As described above, according to the present invention by applying the adhesive bead on the upper portion of the frizz acid of the light collecting sheet, there is an effect that can mitigate the spectrum mura and hot band phenomenon without having a separate optical sheet through the adhesive bead .

As a result, the thickness of the backlight unit may be reduced compared to the existing one, and thus, the light weight and thin liquid crystal display may be implemented, and the efficiency of the process may be improved.

In addition, the prism acid of the light collecting sheet can be prevented from being damaged, and the wet-out phenomenon can be prevented from occurring. Therefore, the display screen of the liquid crystal display device can be realized with high quality of uniform luminance. There is.

1 is an exploded perspective view of a side light backlight unit.
Figures 2a to 2b and 3a to 3b are photographs showing the conventional problem.
4 is an exploded perspective view schematically illustrating a liquid crystal display according to an exemplary embodiment of the present invention.
5 is an exploded perspective view of the backlight unit of FIG. 4.
6 is a cross-sectional view schematically showing the structure of a light collecting sheet according to an embodiment of the present invention.
7 is a cross-sectional view schematically showing the structure of a light collecting sheet according to another embodiment of the present invention.
8 is a photograph when driving the liquid crystal display using the light collecting sheet according to the embodiment of the present invention.
9 is a photograph of a liquid crystal display device using a light collecting sheet according to an embodiment of the present invention.
10 is a schematic view of a light collecting sheet manufacturing method of an embodiment of the present invention.

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

4 is an exploded perspective view schematically illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

As shown, the liquid crystal display device includes a liquid crystal panel 110 and a backlight unit 120, a support main 130, a cover bottom 150, and a top for modularizing the liquid crystal panel 110 and the backlight unit 120. It consists of a cover 140.

Looking at each of them in detail, first, the liquid crystal panel 110 plays a key role in image expression, and includes the first and second substrates 112 and 114 bonded to each other with the liquid crystal layer interposed therebetween. .

In this case, under the premise of an active matrix method, although a plurality of gate lines and data lines intersect on the inner surface of the first substrate 112, which is commonly referred to as a lower substrate or an array substrate, pixels are defined. Thin film transistors (TFTs) are provided at each intersection to be connected one-to-one with the transparent pixel electrodes formed in each pixel.

In addition, an inner surface of the second substrate 114, called an upper substrate or a color filter substrate, includes color filters of R, G, and B colors, and the gate lines and the data lines. In addition, a black matrix covering a non-display element such as a thin film transistor is provided. In addition, a transparent common electrode covering them is provided.

In addition, the printed circuit board 117 is connected through at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board, thereby supporting the side or cover of the support main 130 in the modularization process. (150) It is folded to the back and adheres.

In the liquid crystal panel 110 having the above-described structure, a signal for turning on / off the thin film transistor is sequentially scanned and applied to the gate line, so that the image signal of the data line is applied to the pixel electrode of the selected pixel. When is transferred, the liquid crystal molecules between the first and second substrates 112 and 114 are driven by the electric field therebetween, and various images can be displayed by the change in the transmittance of light.

In this case, polarizing plates (not shown) for selectively transmitting only specific polarized light are attached to outer surfaces of the first and second substrates 112 and 114.

Although not clearly shown in the drawings, the upper and lower alignment layers for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer, and filled therebetween. Seal patterns are formed along edges of both substrates 112 and 114 to prevent leakage of the liquid crystal layer.

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

The backlight unit 120 includes a lamp 129a, a reflecting plate 125, a light guide plate 123 seated on the reflecting plate 125, and an optical sheet 121 positioned thereon.

The lamp 129a described above is located at one side of the light guide plate 123 to face the light incident part of the light guide plate 123, and the lamp 129a is guided to the outside by the lamp guide 129b.

In this case, the light guide plate 123 evenly spreads the light incident from the lamp 129a to the inside of the light guide plate 123 by propagating the light inside the light guide plate 123 by a plurality of total reflections to provide a surface light source to the liquid crystal panel 110. do.

The light guide plate 123 may include a pattern of 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.

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

In addition, the optical sheet 121 on the light guide plate 123 includes a diffusion sheet 127 and at least one light collecting sheet 200, and an adhesive bead is coated on the light collecting sheet 200 of the present invention. It is characterized by.

The adhesive bead is a diffusion bead that scatters light, and the light passing through the light guide plate 123 is focused or diffused through the light collecting sheet, so that a more uniform surface light source is incident on the liquid crystal panel 110.

Here, by spreading the light through the adhesive bead can prevent the occurrence of spectral mura and hot band, in addition to the role of diffusing the light, the adhesive bead can take the role of the existing protective sheet (21c in Figure 1). Can be.

That is, the surface of the light collecting sheet 200 may be prevented from being damaged through the adhesive bead.

In addition, it is also possible to prevent the wet-out phenomenon through the adhesive bead. We will discuss this in more detail later.

Accordingly, the light emitted from the lamp 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. Spread evenly over a wide area and processed into a uniform high-quality light that does not occur spectral mura, hot bands and wet-out phenomenon while passing through the optical sheet 121 and then incident on the liquid crystal panel 110, using the liquid crystal The panel 110 may display a high brightness 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 is the top and side surfaces of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover an edge thereof is configured to open an entire surface of the top cover 140 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 seated, and which is the basis for assembling the entire apparatus of the liquid crystal display device, has a rectangular shape and has one side 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.

In this case, the top cover 140 may also be referred to as a case top or a top case, and the support main 130 may also be referred to as a guide panel, a main support, or a mold frame, and the cover bottom 150 may be referred to as a bottom cover or a lower cover. It is also built.

The liquid crystal display device of the present invention is reduced in overall thickness compared to the conventional liquid crystal display device, because the thickness of the backlight unit 120 that has the greatest effect on the thickness of the liquid crystal display device compared with the conventional.

That is, the conventional backlight unit 20 of FIG. 1 includes a diffusion sheet (21a of FIG. 1), a light collecting sheet (21b of FIG. 1), and a protective sheet (21c of FIG. 1) on the light guide plate (23 of FIG. 1). Although provided with a plurality of optical sheets, the present invention can delete the protective sheet (21c of FIG. 1) on the top of the light collecting sheet 200, the thickness of the backlight unit 120 is reduced compared to the conventional.

In addition, the backlight unit 120 of the present invention does not need to interpose a plurality of optical sheets on the light collecting sheet 200 in order to prevent spectral mura and hot bands, and thus the thickness of the backlight unit 120 is also existing. It can be reduced compared to.

Accordingly, the liquid crystal display device of the present invention can realize a light weight and a thin shape, and many components of the backlight unit 120 have increased the working process time in the modularization process of the liquid crystal display device, thereby reducing the efficiency of the process. Compared to this, the working time can be shortened, improving the efficiency of the process.

The backlight unit 120 may be manufactured at a lower cost than before.

In addition, the light collecting sheet 200 of the present invention may prevent the surface from being damaged even when the protective sheet (21c of FIG. 1) is not provided, and prevent the wet-out phenomenon from occurring.

5 is an exploded perspective view of the backlight unit of FIG. 4, and FIG. 6 is a cross-sectional view schematically illustrating a structure of a light collecting sheet according to an embodiment of the present invention.

As shown in FIG. 5, the backlight unit 120 includes a white or silver reflecting plate 125 seated on the cover bottom 150 of FIG. 4, and a lamp 129a which is a light source arranged along the longitudinal direction of one edge thereof. ), A light guide plate 123 positioned on the same plane as the lamp 129a and seated on the reflector 125, and having at least one side facing the lamp 129a, and a diffusion sheet 127 seated on the light guide plate 123. ) And a light collecting sheet 200.

In addition, a lamp guide 129b for guiding the lamp 129a is further provided. The lamp guide 129b surrounds the upper and lower sides and the outside of the lamp 129a in a state in which the inner side toward the light guide plate 123 is opened, and the lamp ( In addition to the protection of 129a, light is concentrated in the direction of the light guide plate 123.

In this case, as the light source, the lamp 129a may be a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp. Alternatively, a light-emitting diode lamp other than the fluorescent lamp may be used as the lamp 129a, and the lamp guide 129b may be deleted when the light-emitting diode lamp is used.

The light guide plate 123 is made of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials capable of transmitting light, or is made of polycarbonate (PC). It is manufactured in a flat type.

In addition, the reflector plate 125 is positioned below the light guide plate 123 and reflects the light passing through the lower surface of the light guide plate 123 toward the liquid crystal panel (110 of FIG. 4) to improve the brightness of the light.

In addition, the diffusion sheet 127 over the light guide plate 123 diffuses the light passing through the light guide plate 123, thereby preventing the light from being partially concentrated. The diffusion sheet 127 also serves to adjust the direction of light so that light travels toward the light collecting sheet 200 positioned on the diffusion sheet 127.

The light collecting sheet 200 on the diffusion sheet 127 diffuses or collects light passing through the diffusion sheet 127 to inject a more uniform surface light source into the liquid crystal panel (110 of FIG. 2). The prism acid 210 is formed to condense light in the direction of the liquid crystal panel, and the adhesive bead 220 is formed on the light collecting sheet 200 to further disperse the light incident through the diffusion sheet 127. While controlling the direction of the light.

As a result, spectral mura and hot band phenomena can be alleviated, and thus it is not necessary to further stack separate optical sheets on the light collecting sheet 200.

In particular, the light collecting sheet 200 of the present invention is a prism acid of the light collecting sheet 200 through the adhesive bead 220, even if a separate protective sheet (21c of FIG. 1) is not located on the light collecting sheet 200. 210 may be prevented from being damaged and a wet-out phenomenon may be prevented from occurring.

Here, referring to FIG. 6, the light collecting sheet 200 according to the embodiment of the present invention will be described in more detail. The light collecting sheet 200 according to the embodiment of the present invention transmits light passing through the diffusion sheet 127 to the liquid crystal panel (110 of FIG. 4). By diffusing and condensing toward), a plurality of optical sheets including a protective sheet (21c of FIG. 1) provided on the light collecting sheet 200 may be deleted.

As illustrated in FIG. 6, the light collecting sheet 200 may include a support layer 211 made of transparent PMMA (polymethylmethacrylate) that transmits light, polyethylene terephthalate (PET), and the like, and an upper surface of the support layer 211. It consists of the light condensing layer 213 for condensing light.

The light collecting layer 213 formed on the upper surface of the support layer 211 is formed to collect light. The light collecting layer 213 is arranged adjacent to each other in a band shape along the longitudinal direction of the support layer 211 so that peaks and valleys are repeated. A plurality of prismatic mountains 210 in a form are arranged in a row to protrude from the support layer 211.

The prism mountain 210 has first and second inclined surfaces that are inclined at a predetermined angle from the vertices.

Due to the prism acid 210, the light collecting sheet 200 improves the light collecting efficiency of light to the liquid crystal panel (110 of FIG. 4). This has a brightness rising effect.

At this time, the angle of the corner forming the vertex of the prism 210 is 80 to 90 degrees.

That is, at this time, the first and second inclined surfaces of the prism mountain 210 are formed to be inclined by about 45 to 50 degrees from the support layer 211, respectively, so that the corners formed by the first and second inclined surfaces form 80 to 90 degrees. will be.

Here, the light collecting layer 213 may be formed integrally with the support layer 211 or made of different materials. When the light collecting layer 213 is made of different materials, the light collecting layer 213 may be formed of incident light such as acrylic, urethane, polyester, or the like. Any material that can enhance the light collecting property is possible.

In particular, the light collecting sheet 200 of the present invention is characterized in that the adhesive bead 220 is positioned between the neighboring prism acid 210.

The adhesive bead 220 is a diffusion bead that evenly diffuses the light, the adhesive bead 220 is included in the acrylic resin, the adhesive bead 220 is a light by dispersing the light passing through the light collecting layer 213. Partial compaction can be prevented.

The adhesive beads 220 may be made of, for example, a thermosetting resin such as an acrylic resin, a urethane resin, a polyester resin, and the like, and preferably an epoxy acrylate resin. It may be made of an ultraviolet curable resin such as (epoxy acrylate resin), urethane acrylate resin (urethane acrylate resin) and silicone acrylate resin (silicone acrylate resin).

In particular, the adhesive bead 220 of the present invention is characterized in that the beads themselves are tacky, so that the bead 220 is located on top of the prism acid 210 of the light collecting layer 213. The advantage is that no separate methods are required for fixing.

That is, since the beads are not self-adhesive, separate methods are required for fixing the beads in a microchannel such as an acrylic resin.

As a method of fixing the beads used to date, the method of confining beads in a microchannel using a physical barrier, fixing using a magnetic field, and using an ultrasonic wave or a laser tweezer are typical. The same methods cause problems in that the selection of beads is limited, the machining process for manufacturing the beads is complicated, the noise in optical measurement is large, and the process cost is improved.

On the contrary, since the bead 220 itself has adhesiveness, the adhesive bead 220 of the present invention forms a bead 220 on the light collecting sheet 200, and does not require separate methods, thereby making it more efficient. As a result, the adhesive bead 220 may be formed on the light collecting sheet 200.

At this time, by lowering the temperature of the adhesive bead 220 below the glass transition temperature (Tg) of the bead 220 itself, it becomes adhesive.

Therefore, there is no restriction in the selection of the adhesive bead 220, and the processing process for manufacturing the adhesive bead 220 is not complicated.

In addition, by not requiring a separate micro oil in addition to the adhesive bead 220, it is possible to prevent the large noise caused by the micro oil during optical measurement, and to reduce the process cost.

At this time, the size of the adhesive bead 220 is preferably to have a size that can protrude about 1 ~ 50㎛ from the prism acid 210 of the light collecting sheet 200.

Therefore, the adhesive bead 220 may prevent the prism acid 210 of the light collecting sheet 200 from contacting with an external object, in addition to scattering light, thereby preventing the prism acid 210 from being damaged. It can prevent the occurrence of wet-out phenomenon.

Here, the wet-out phenomenon is an increase in the surface area in contact with the prism acid 210 and the adjacent sheet, a problem caused by this, the two surfaces are in optical contact with each other to transfer light from one film to the next film This happens when the change in refractive index is eliminated.

This is particularly well recognized when moisture penetrates inside the liquid crystal display module under high temperature and high humidity conditions.

As a result, the viewer recognizes that the screen image is mottled and changes appearance from time to time. The light collecting sheet 200 of the present invention has a spherical adhesive bead on the prism acid 210 of the light collecting sheet 200. By forming the 220, the surface area in contact with the sheet positioned on the light collecting sheet 200 through the adhesive bead 220 may be prevented from increasing.

Therefore, the backlight unit 120 including the light collecting sheet 200 of the present invention can reduce the thickness of the backlight unit 120 as compared to the conventional one, thereby implementing a lightweight and thin liquid crystal display device, and improving the efficiency of the process. Will be improved.

In addition, even without a separate optical sheet such as a protective sheet (21c in FIG. 1) can prevent the spectral mura and hot band, it is possible to prevent the prism acid 210 of the light collecting sheet 200 is damaged. Therefore, the wet-out phenomenon can be prevented from occurring.

On the other hand, the light collecting sheet 200 of the present invention may form a diffusion layer 215 on the opposite side of the support layer 211 on which the light collecting layer 213 is formed, that is, on the lower surface, while further dispersing the light through the diffusion layer to change the direction of the light. I can adjust it.

In this case, the diffusion layer is configured to have a haze characteristic of 0 to 15%.

Here, the haze characteristic is a phenomenon in which light is diffused according to the intrinsic properties of the material in addition to reflection or absorption depending on the type of material when light passes through the transparent material. Can be measured according to

Haze (%) = (total amount of light delivered-straight light amount / total amount of light transmitted) X 100 ......... Equation (1)

In particular, the diffusion layer 215 of the composite optical sheet 200 of the present invention preferably has a haze characteristic of 3 to 10%.

As such, in order for the diffusion layer 215 to have haze characteristics, the diffusion layer 215 may include light diffusing components such as beads 215a, or may not include the beads 215a and may have fine patterns on the lower surface thereof. It may be configured to form.

At this time, the bead 215a is configured to be included in the acrylic resin, the bead (not shown) has a feature that can prevent the light is partially concentrated by dispersing the light incident on the support layer 211.

In addition, the diffusion layer 215 that does not include the bead 215a has a feature that can adjust the light scattering angle according to the shape of the fine pattern (not shown), the fine pattern (not shown) is an elliptical pattern (elliptical pattern) , Polygonal pattern, etc., and the hologram pattern is used to refract the incident light by the interference pattern in an asymmetrical direction so that the collected light diffuses at a more inclined angle. You can do that.

As a result, light is dispersed through the diffusion layer 215 to prevent the light from being partially concentrated.

On the other hand, as shown in FIG. 7, the light collecting sheet 200 may be formed such that the light collecting layer 213 and the dome-shaped lenticular lens 310 in addition to the prism acid 210 are arranged in a row from the support layer 211. However, since the adhesive bead 220 is positioned between the lenticular lens 310 and the condenser sheet 200, the neighboring lenticular lens 310, the thickness of the backlight unit (120 of FIG. 3) may be reduced as compared with the conventional lens. A lightweight and thin liquid crystal display device can be implemented, and the efficiency of the process can be improved.

In addition, it is possible to prevent the spectral mura and hot band without including a separate optical sheet such as a protective sheet (21c of FIG. 1), it is possible to prevent the lenticular lens 310 of the light collecting sheet 200 is damaged. Therefore, the wet-out phenomenon can be prevented from occurring.

In this case, the adhesive bead 220 positioned on the lenticular lens 310 may have a size that may protrude from about 1 to 50 μm from the lenticular lens 310.

8 is a photograph of a liquid crystal display using a light collecting sheet according to an embodiment of the present invention, and it can be seen that light leakage, spectrum mura, and hot band do not appear on a screen.

As a result, the light emitted from the lamp 129a is guided to the light guide plate 123 by the lamp guide 129b, and then is refracted in the direction of the liquid crystal panel (110 in FIG. 4), and uniform luminance is passed through the diffusion sheet and the light collecting sheet. It is processed to a high quality and is incident on the liquid crystal panel (110 of FIG. 4), whereby the liquid crystal panel (110 of FIG. 4) displays an image to the outside.

That is, the light collecting sheet 200 of the present invention diffuses or collects light passing through the diffusion sheet so that a more uniform surface light source is incident on the liquid crystal panel (110 of FIG. 4).

Therefore, it is not necessary to stack additional optical sheets on top of the light collecting sheet 200, so that the backlight unit (120 of FIG. 5) can be manufactured at a lower cost, and the working process time in the modularization process of the liquid crystal display device. The efficiency of the process can be improved by reducing the

9 is a photograph of a liquid crystal display using the light collecting sheet according to the embodiment of the present invention, it can be seen that the wet-out phenomenon between the light collecting sheet and the panel does not appear.

Therefore, the backlight unit (120 of FIG. 5) including the light collecting sheet 200 of the present invention can reduce the thickness of the backlight unit (120 of FIG. 5) as compared with the conventional one, thereby implementing a lightweight and thin liquid crystal display device. And improve the efficiency of the process.

10 is a schematic view of a light collecting sheet manufacturing method of an embodiment of the present invention.

As illustrated, the light collecting sheet 200 (in FIG. 5) includes a diffusion layer coating part 401, a film introduction part 403, a resin dropping part 405, a pattern forming part 407, and a hardening part 409. In particular, it further comprises a viscous bead coating portion 411.

At this time, the support layer 211 provided to the film introduction portion 403 moves to the curing portion 409 by driving the plurality of rollers 420.

In this case, the support layer 211 is made of polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), which is a thermoplastic resin, and the support layer 211 is first supported by the diffusion layer coating part 401 before being provided to the film introduction part 403. The diffusion layer 215 is coated on one surface of 211.

The diffusion layer 215 may be formed by dipping the support layer 211 in the bath 410 containing the diffusion material 412.

The support layer 211 having the diffusion layer 215 formed on one surface thereof hardens the diffusion layer 215 through a predetermined time. In this case, the diffusion material 412 may include a bead, and when the diffusion layer 215 is not included, Fine patterns may be formed on the bottom surface of the diffusion layer 215.

Next, the support layer 211 in which the diffusion layer 215 is formed is provided to the film introduction portion 403, and the support layer 211 is moved to the resin dropping portion 405 so that the resin 213a for the upper portion of the support layer 211 is provided. Dropping

In this case, the resin 213a is a transparent acrylic series and is dropped on the opposite surface of the support layer 211 on which the diffusion layer 215 is formed, thereby forming the resin layer 213b on the support layer 211.

Next, in the pattern forming unit 407, the surface of the resin layer 213b on the support layer 211 is pressed with a mold roller 440 in which a pattern in which an acid and a valley are alternated is formed, and the acid and valleys are formed on the surface of the light collecting layer 211. This alternating prism mountain 210 is formed.

At this time, the gap between the support layer 211 and the mold roller 440 is minimized to 0 to 1 μm or less, thereby forming the prism acid 210. For this reason, the prism acid 210 in which the peak and the valley are alternately formed directly from the support layer 211 can be formed.

Next, the support layer 211 having the prism acid 210 formed thereon is cured by irradiating ultraviolet rays from the curing unit 409 to complete the light collecting sheet 200.

Thereafter, the light collecting sheet 200 is moved to the viscous bead applying unit 411 so that the bead 220 having viscosities is coated on the prism acid 210.

At this time, by heating the bead 220, the temperature of the bead 220 is lower than the glass transition temperature (Tg) of the bead 220 itself has a stickiness.

Accordingly, the adhesive beads 220 (hereinafter, referred to as adhesive beads) are applied to the upper portion of the prism acid 210 of the light collecting sheet 200 and are attached and fixed between neighboring prism acids 210. .

As described above, in the present invention, the adhesive beads 220 are applied to the upper portion of the free acid 210 of the light collecting sheet 200, so that the spectral mura and the hot film are not provided through the adhesive beads 220. Band phenomenon can be alleviated.

Through this, the thickness of the backlight unit (120 of FIG. 5) can be reduced as compared to the conventional, so that a lightweight and thin liquid crystal display device can be realized, and the efficiency of the process is improved.

In addition, even if a separate protective sheet (21c of FIG. 1) is not located on the light collecting sheet 200, the prism acid 210 of the light collecting sheet 200 may be prevented from being damaged, and a wet-out phenomenon may occur. Can be prevented.

Meanwhile, in the above description, for convenience, the side light method is used as the liquid crystal display device in which the light collecting sheet 200 according to the present invention may be used. However, this may be applied to the direct type method, in this case, the light guide plate (123 of FIG. 5). And a plurality of lamps (129a of FIG. 5) may be configured on the reflector while the lamp guides (129b of FIG. 5) are removed.

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.

123: light guide plate, 125: reflecting plate, 127: diffusion sheet
129a: lamp, 129b: lamp guide, 200: light collecting sheet
210: prism acid, 220: adhesive beads

Claims (15)

A liquid crystal panel;
A light source positioned under the liquid crystal panel;
A light collecting sheet seated on an upper part of the light source, and having a light collecting layer having a plurality of patterns formed on one surface thereof facing the liquid crystal panel, and having adhesive beads coated on the light collecting layer;
Reflector located under the light collecting sheet
Liquid crystal display comprising a.
The method of claim 1,
The adhesive bead is a diffusion bead, and has a tackiness at or below a glass transition temperature (Tg).
The method of claim 2,
The adhesive beads are acrylic resins, urethane resins and polyester resins, epoxy acrylate resins, urethane acrylate resins and silicones. A liquid crystal display device comprising one selected from acrylate resins.
The method of claim 1,
The adhesive bead is positioned between the light collecting layers adjacent to each other, and the liquid crystal display device protrudes compared to the pattern.
The method of claim 1,
The condensing sheet may include a support layer made of PMMA (polymethylmethacrylate), polyethylene terephthalate (PET), and the like, wherein the condensing layer is a dome-shaped lenticular lens or prism acid pattern protruding from the support layer.
The method of claim 5, wherein
And a diffusion layer having a haze component on the other surface of the support layer on the opposite side of the surface on which the light collecting layer is formed.
The method of claim 1,
The light source is a liquid crystal display device selected from a Cold Cathode Fluorescent Lamp (CCFL), an External Electrode Fluorescent Lamp, and a Light Emitting Diode (LED).
The method of claim 1,
A light guide plate is formed on the reflective plate, and the light source is arranged on one side or both sides of the light guide plate.
A support layer;
A light collecting layer formed on one surface of the support layer and protruding so that a plurality of patterns are arranged adjacent to each other on the support layer;
Adhesive beads applied on top of the patterns adjacent to each other of the light collecting layer
Condensing sheet for a liquid crystal display device comprising a.
The method of claim 9,
The adhesive beads are diffusion beads, and the light collecting sheet for a liquid crystal display device having adhesiveness at a glass transition temperature (Tg) or less.
The method of claim 10,
The adhesive beads are acrylic resins, urethane resins and polyester resins, epoxy acrylate resins, urethane acrylate resins and silicones. Condensing sheet for a liquid crystal display device comprising one selected from acrylate resin (silicone acrylate resin).
The method of claim 9,
The adhesive bead is disposed between the adjacent patterns, the light collecting sheet for a liquid crystal display device protruding compared to the pattern.
Dropping a resin layer on one surface of the support layer;
Pressing the resin layer with a roller to form a pattern in which an acid and a valley are alternated;
Applying a tacky bead on top of the pattern
Method of manufacturing a light collecting sheet for a liquid crystal display device comprising a.
The method of claim 13,
The bead is a manufacturing method of a light collecting sheet for a liquid crystal display device having an adhesive at a temperature below the glass transition temperature (Tg).
The method of claim 13,
Forming a diffusion layer on the other surface of the support layer before dropping the resin layer on one surface of the support layer.

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