KR20110075232A - Light diffusion plate, backlight unit having the same, liquid crystal display device and lighting device - Google Patents

Abstract

PURPOSE: A light diffusion plate, a backlight unit including the same, a liquid crystal display device, and a lighting apparatus are provided to reduce a thickness thereof by enhancing diffusion performance in spite of a short interval between a diffusion plate and a light source. CONSTITUTION: A base material layer(110) includes a light incidence surface which is installed on a bottom surface thereof in order to receive the light. A light emission unit is formed on the base material layer and emits the light to the outside thereof. A plurality of patterns are arranged in a shape of lattice. A bottom surface of the patterns has a shape of a polygon. The patterns are formed with at least three-layer structure.

Description

Light Diffusion Plate, Backlight Unit, Liquid Crystal Display and Lighting Device {Light Diffusion Plate, Backlight Unit Having the Same, Liquid Crystal Display Device And Lighting Device}

The present invention relates to a light diffusion plate, a backlight unit having the same, a liquid crystal display device and an illumination device.

In the case of a liquid crystal display, since it is not a self-light emitting device, a backlight unit is provided on a rear surface of the liquid crystal display. Such a backlight unit may be broadly classified into a direct type that is mainly applied to a large size such as a TV and a digital information display (DID), and an edge type that is mainly applied to a small size such as a monitor and a notebook.

In the case of the direct type method, it is difficult to obtain uniform luminance on the front surface because a plurality of light sources having a bar shape (Cold Cathode Fluorescent Lamp, External Electrode Fluorescent Lighting) or dot shape (Light Emitting Diode) are used. Therefore, light is uniformly distributed over the entire liquid crystal display using a light diffusing plate, and then a diffuser sheet, a prism sheet, a micro lens sheet or a light luminance polarizing sheet is arranged on the uppermost side of the light diffusing plate above, if necessary. This is solved by uniformly emitting or condensing light to the front.

The backlight unit uses a plurality of lamps as a light source to implement high brightness. As such, when the plurality of lamps are used, there is a problem that the manufacturing cost is increased and the amount of power used is increased because the lamps are expensive. In order to solve this problem, it is necessary to configure a backlight unit in which the number of lamps is reduced. In order to reduce the number of lamps to form a predetermined pattern on the light diffusion plate, the shape of the pattern is very important as the brightness and uniformity vary depending on the shape of the pattern.

Meanwhile, scratches may occur on the surface of the light diffusion plate in various situations such as assembling, storing or transporting the light diffusion plate or the backlight unit including the same. If a scratch occurs in the light diffusion plate, the light is not diffused normally and the quality of the liquid crystal display is degraded. In order to prevent this, a protective film is additionally required. However, there is a problem that the cost increases when adding a protective film. Accordingly, there is a need for a light diffusion plate, a backlight unit, and a liquid crystal display including the same, which can improve the quality of the light diffusion plate and reduce the cost.

The present invention is excellent in brightness and uniformity can be reduced the number of light sources, strong scratches do not require a protective film as well as a light diffusion plate that can be slimmed excellent diffusion performance, even if the distance between the diffusion plate and the light source, It is to provide a backlight unit, a liquid crystal display device and an illumination device having the same.

The light diffusion plate of the present invention for achieving the above object,

A base layer having a light incidence surface into which light from a light source is incident on a bottom surface thereof, and a light emission surface on which the light exits from the outside, the plurality of patterns being arranged in a lattice shape; The pattern is characterized in that the bottom surface is a polygonal, polygonal pyramidal shape consisting of at least three layered structure in which the lower inner corner of the side cross-section is gradually reduced.

The pattern is preferably a polygonal pyramid consisting of a first layer, a second layer, and a third layer, the bottom of which is rectangular in shape, and the lower inner corner of the side cross section gradually decreases.

It is preferable that the said pattern has a square bottom face, and P is 100 micrometers-350 micrometers when length of one side is P.

It is preferable that the height h of the said pattern is 50 micrometers-500 micrometers.

When the height of the first layer is h1, the height of the second layer is h2, and the height of the third layer is h3, h1> h2> h3.

Another pattern adjacent to the pattern may be continuously connected without a spacing distance, or the pattern may be spaced apart from another pattern adjacent thereto, and the separation distance c may be 0.1 μm to 20 μm.

The pattern may be formed in an embossed shape protruding upward on the base layer or in an intaglio shape recessed downward on the base layer.

It is preferable that the roughness is further formed on at least one of the light incidence surface of the base material layer or the light emission surface of the pattern.

The functional layer may be further provided on at least one surface of the light incident surface or the light exit surface of the substrate layer.

At least one of the base layer or the functional layer may be made of a transparent resin and a light diffusing agent. In addition, at least one of the base layer or the functional layer may include at least one selected from among ultraviolet absorbers, heat stabilizers, antioxidants, antistatic agents, fluorescent brighteners, and release agents.

The backlight unit according to the invention is characterized in that it comprises the light diffusion plate according to the invention described above.

Illumination apparatus according to the invention is characterized in that it comprises a light diffusion plate and a light source according to the invention described above.

The liquid crystal display according to the present invention is characterized in that it comprises a backlight unit and a light source including the light diffusion plate according to the present invention described above.

In the lighting device and the liquid crystal display, the light source may be an LED, and the LED is preferably a lens type.

The light diffusing plate according to the present invention has a high brightness and uniformity when applied to the backlight unit can reduce the number of lamps, it is resistant to scratches has the effect of not having to provide a separate protective film. Accordingly, the light diffusion plate may be usefully applied to a backlight unit, a liquid crystal display, and an illumination device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention.

1 is a perspective view of a light diffusion plate according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the light diffusion plate shown in Figure 1, Figure 3 is a perspective view of the pattern shown in Figure 1, Figure 4 is a view 1 is a plan view of the pattern shown in FIG. 1, and FIG. 5 is a side cross-sectional view of the pattern shown in FIG.

As shown in FIGS. 1 to 5, in the light diffusion plate 100 according to the present invention, a base layer 110 and a plurality of patterns 120 formed on the base layer 110 are arranged in a lattice shape. .

The base layer 110 includes a substantially flat light incident surface 111 through which light is incident from a light source or a lamp.

The pattern 120 is formed on the opposite surface of the light incident surface 111 of the base layer 110, the light exit surface 112 is provided on the outside, a plurality of patterns 120 are arranged in a grid shape.

The thickness of the base layer 110 is not limited, but may be 0.1 mm to 4.0 mm. If the thickness of the base layer 110 is less than 0.1mm, the light diffusion plate 100 is difficult to maintain a constant stiffness, and thus has the disadvantage of not supporting the optical subsidiary material that rises above the light diffusion plate 100. Accordingly, the base layer 110 has a certain thickness, so that the necessary rigidity as the light diffusion plate 100 is obtained and the optical subsidiary material must be protected from heat generated from the light source. When the thickness of the base layer 110 exceeds 4mm, the amount of raw and subsidiary materials is increased to increase the manufacturing cost of the light diffusion plate 100. In addition, as the thickness increases, the weight of the direct backlight unit increases.

The base layer 110 may include a transparent resin and a light diffusing agent having a diffusion function.

The transparent resin is at least one selected from an acrylic resin, a styrene-acrylic copolymer resin, a styrene resin, a styrene-acrylonitrile resin, and a polycarbonate resin, which is inexpensive and has high light transmittance and shows excellent durability. desirable.

The acrylic resin may be a methacrylic acid alkyl ester such as methyl methacrylate, ethyl methacrylate, butyl methacrylate or 2-ethylhexyl methacrylate; Alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; Methacrylic acid cycloalkyl esters such as cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate and dicyclopentanyl methacrylate; Acrylic acid cycloalkyl esters such as cyclohexyl acrylate and 2-methylcyclohexyl acrylate; Methacrylic acid aryl esters such as phenyl methacrylate and benzyl methacrylate; It is preferable that it is any one homopolymer or 2 or more types of copolymers chosen from acrylic acid aryl ester, such as phenyl acrylate and benzyl acrylate.

The styrene-acrylic copolymer resin may include at least one selected from methacrylic acid alkyl ester, acrylic acid alkyl ester, methacrylic acid cycloalkyl ester, acrylic acid cycloalkyl ester, methacrylic acid aryl ester and acrylic acid aryl ester, and styrene and α-methyl. Preference is given to at least one copolymer selected from styrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene.

In addition, the styrene resin is preferably any one homopolymer or a copolymer thereof selected from styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, and p-methoxystyrene.

Polycarbonate resins are also groups of linear and branched aromatic polycarbonate homopolymers, polyester copolymers, or mixtures of one or more thereof, prepared by reacting dihydroxy phenol with phosgene or by reaction of dihydroxy phenol with a carbonate precursor. This is preferred.

The light diffusing agent is preferably used alone or in combination of one or more of organic particles and inorganic particles. For example, silicone-based, acrylic, styrene-based, methyl methacrylate / styrene copolymer-based, polycarbonate-based, butyl acrylate, olefin-based crosslinked or uncrosslinked fine particles, silica, talc, calcium carbonate, barium sulfate, titanium dioxide (TiO ₂ ) and the like can be used. In addition to the use of a material, the light diffusing agent includes all components applied for light diffusion, such as forming pores in the base layer 110.

The size of the light diffusing agent is suitably 0.5 μm to 50 μm. Preferably, the light diffusing agent is suitably 0.8 μm to 35 μm. When the size of the light diffusing agent is less than 0.5 μm, there is a problem in that the dispersibility with the transparent resin is poor. If the size of the light diffusing agent exceeds 50㎛ has a disadvantage in that the light diffusion performance is reduced compared to the same amount of light can not diffuse.

The light diffusing agent may be used in an amount of about 0.001 parts by weight to 5 parts by weight based on 100 parts by weight of the transparent resin used in the base layer 110, and more preferably 0.01 parts by weight to 2 parts by weight. When the light diffusing agent is less than 0.01 part by weight, the incident light cannot be diffused, and when the light diffusing agent is more than 2 parts by weight, the transmittance of the light is lowered, thereby lowering the luminance.

The base layer 110 may further include at least one selected from ultraviolet absorbers, heat stabilizers, antioxidants, antistatic agents, fluorescent brighteners, and release agents known in the art.

The ultraviolet absorbers include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and formamidine ultraviolet absorbers, and these may be used alone or in combination of two or more. Although the content of the ultraviolet absorber is not limited, it is 0.001 to 5 parts by weight, preferably 0.01 to 2 parts by weight based on 100 parts by weight of the transparent resin used for the base layer 110. When the ultraviolet absorbent is included in the above range on the basis of the above may provide a light diffusion plate 100 stable to the ultraviolet.

The thermal stabilizers include piperidinyl esters, oxazolidines and piperidino oxazolidines, pyrridispyroacetals, and diazacycloalkanones, which may be used alone or in combination of two or more thereof. Can be. Although the content of the thermal stabilizer is not limited, it is 0.001 to 5 parts by weight, preferably 0.01 to 2 parts by weight based on 100 parts by weight of the transparent resin used for the base layer 110. When the heat stabilizer is included in the above range on the basis of the above, it is possible to provide a light diffusion plate 100 that is stable at high temperatures.

As said antioxidant, a phenolic antioxidant, phosphorus antioxidant, sulfur-type antioxidant, etc. are mentioned, Among these, a phenolic antioxidant and phosphorus antioxidant are preferable. In particular, the phenolic antioxidant can be most preferably used because it can prevent coloring of the molded body due to heat, oxidative degradation, or the like, without lowering transparency, heat resistance, or the like. The content of the antioxidant is 0.001 to 5 parts by weight, preferably 0.01 to 2 parts by weight based on 100 parts by weight of the transparent resin used for the intervening layer. When the antioxidant is included in the above range on the basis of the above may provide a light diffusion plate 100 having excellent antioxidant properties.

Examples of the antistatic agent include water-soluble metal oxide particles, conductive polymers, surfactants, hydrophilic monomers, and ion conductive monomers. Among them, conductive polymers having excellent heat resistance and surfactants having excellent permeability and antistatic properties are preferably used. Can be used. More preferably, a cationic surfactant having a quaternary amine salt structure having advantages of excellent antistatic properties and dispersibility is preferable. In general, in order to show the antistatic performance, the surface resistivity should show 10 ¹¹ Ω / ㎠ or less, and the content can be appropriately adjusted in consideration of this. In addition, in the case of the light diffusion plate 100, it is important to form a transparent film, so it is good to adjust the material and content in consideration of this.

The pattern 120 is formed on a surface opposite to the light incident surface 111 of the base layer 110, and a plurality of patterns 120 are provided in a lattice shape. In this case, the pattern 120 may be integrally formed on the base layer 110, and the pattern 120 may be formed in an embossed shape protruding upward on the base layer 110.

The pattern 120 serves to diffuse light from the light source and increase light condensing efficiency. Of course, the front uniformity and brightness with respect to light are thus improved. In addition, cost can be reduced by minimizing the use of optical subsidiary materials.

In general, when using multiple lamps, the image of the lamp is visually identified by the difference between the light and dark areas. If the image of the lamp is visually identified, the quality of the liquid crystal display device is degraded, which requires the use of optical subsidiary materials, which increases the cost. In addition, when a plurality of lamps are used, the amount of power increases, which increases the power consumption of the liquid crystal display. However, as in the present invention, the plurality of patterns 120 are disposed on the base layer 110 in a lattice shape, and the shape of the pattern 120 is polygonal at the bottom, and at least three lower inner corners of the side cross sections are gradually reduced. In the case of a polygonal pyramidal shape having a layered structure, the number of lamps can be reduced because of excellent brightness and uniformity, and the image of the lamp cannot be visually identified. Therefore, the use of optical subsidiary materials can be minimized. In addition, even if the distance between the diffuser and the light source is close, the diffusion performance is excellent and slimming is possible.

As described above, when the pattern 120 is a polygonal pyramid consisting of at least three layered structures in which the lower end angle of the side cross-section is gradually reduced, the luminance uniformity becomes very high due to the refraction of light incident from the bottom surface.

According to a preferred embodiment of the present invention, as shown in the drawing, the pattern 120 has a bottom surface having a rectangular shape, more preferably, a bottom surface having a square shape, and a first layer 121 having a lower inner corner of a side cross-section gradually decreased, It is preferable that it is a polygonal pyramid consisting of the second layer 122 and the third layer 123. That is, the lower inner angle θ1 of the side cross section of the first layer, the lower inner angle θ2 of the side cross section of the second layer, and the lower inner angle θ3 of the side cross section of the third layer satisfy θ1> θ2> θ3, respectively.

In this case, when the length of one side of the pattern 120 is P, the p is 100 μm to 350 μm, and more preferably, p is 200 μm to 300 μm. In addition, the height h of the pattern 120 may be 50㎛ to 500㎛. The length p and height h of the one side are mutually influential data, and it is difficult to clearly define the critical effect. However, it is important that there is a problem that the light efficiency is lowered and the brightness is lowered when the range of the p and h phases is out of the above range.

Here, the distance to the outside based on the boundary between the first layer and the second layer is called P3, and the distance to the boundary between the first layer and the second layer is determined based on the boundary between the second layer and the third layer. When the distance from the center of the third layer to the boundary between the second layer and the third layer is P1, P satisfies 2 (P1 + P2 + P3). Here, P1, P2, and P3 may be different from each other or the same, and may be appropriately changed as necessary.

In addition, when the height of the first layer is h1, the height of the second layer is h2, and the height of the third layer is h3, h satisfies h1 + h2 + h3. Here, h1, h2, and h3 may be different from each other or the same, and this may be appropriately changed as necessary. Preferably, h1, h2 and h3 preferably satisfy h1> h2> h3.

It is difficult to clarify the range and critical significance as data affecting each other, but in general, when p is less than 100 μm, it is difficult to form a pattern 120 of this size. The pattern 120 is recognized on the screen of the display device, which may deteriorate the quality. In addition, when the height h of the pattern 120 is less than 50 μm, it is difficult to form the pattern 120 of the size. When the height h of the pattern 120 exceeds 500 μm, the screen of the liquid crystal display device is There is a disadvantage that the pattern 120 is recognized, thereby degrading the quality.

In this case, the pattern 120 and another neighboring pattern 120 may be continuously connected without a separation distance. That is, the plurality of patterns 120 may be densely arranged without a distance from each other.

Forming method for manufacturing the light diffusion plate 100 is not limited, extrusion molding, vacuum molding, hot press molding, co-extrusion molding, film lamination method, solvent bonding method, surface coating method, ultraviolet curing method, thermal curing method Various methods can be used. The easiest way to do this is by extrusion. In addition, although not shown in the drawing, the pattern 120 may be manufactured by cutting a cylindrical roll to form the same shape as the pattern 120 in an intaglio shape.

6 is a cross-sectional view of a light diffusing plate according to another embodiment of the present invention.

As shown in FIG. 6, the light diffusion plate 100a includes a base layer 110 and a plurality of patterns 120 formed on the base layer 110. Here, since the substrate layer and the pattern are as described above, a detailed description thereof will be omitted.

In this case, the pattern 120 and the other pattern 120 adjacent to each other may be formed at a predetermined distance, and the separation distance c may be 0.1 μm to 20 μm. If the separation distance is less than 0.1㎛, there is a disadvantage in that it is difficult to form the pattern 120 of such a size, if the separation distance exceeds 20㎛ there is a problem that the image of the lamp is visible and the quality of the liquid crystal display device is deteriorated do.

7 is a cross-sectional view of a light diffusing plate according to another embodiment of the present invention.

As shown in FIG. 7, the light diffusion plate 100b includes a base layer 110 having a light incident surface 111 through which light from a light source is incident, and a light incident surface 111 of the base layer 110. It is formed on the opposite side of the) includes a plurality of patterns 120 having a light exit surface (112). In this case, functional layers 130 and 140 may be further formed on at least one of the light incident surface 111 and the light exit surface 112 to improve durability and weather resistance.

Since the substrate layer 110 and the pattern 120 are as described above, a detailed description thereof will be omitted.

The thickness of the functional layer (130, 140) is not limited, but 0.05mm to 1.5mm is preferred. When the thicknesses of the functional layers 130 and 140 are included in the above range, good durability may be obtained and excellent light diffusion rate may be achieved.

When the functional layers 130 and 140 are formed on both the light incident surface 111 and the light exit surface 112, the thickness of the functional layer 130 formed on the light incident surface 111 and the light exit surface 112 are described. The thickness of the functional layer 140 to be formed in the same or may be formed differently. For example, when the thickness of the functional layer 130 formed on the light incident surface 111 is t1, the thickness t1 may be 0.01 mm to 0.1 mm. In addition, when the thickness of the functional layer 140 formed on the light exit surface 112 is t2, the thickness t2 may be 0.0025mm to 0.1mm.

Typically, the light exit surface 112 of the light diffusion plate has an increased surface area compared to the light incident surface 111. At this time, when the same amount of extrusion of the functional layer (130,140) of the light exit surface 112 and the light incident surface 111 is made the same, the portion where the surface area is increased becomes relatively thin, the portion where the surface area is relatively small The thickness is formed thick. In addition, in the direct type backlight unit, the light incident surface 111 is directly irradiated with ultraviolet rays emitted from the lamp. Therefore, the thickness t1 is preferably formed thicker than the thickness t2.

The functional layers 130 and 140 may be made of a transparent resin, and preferably, may further include light diffusing agents 131 and 141.

The transparent resin used for the functional layers 130 and 140 is not limited, and preferably the same resin as the base layer 110 may be used.

In addition, the light diffusing agents 131 and 141 used in the functional layers 130 and 140 may be the same as those exemplified as the light diffusing agent 113 of the substrate layer 110 described above, and the size thereof is 10 μm to 35 μm. Is preferably. When the sizes of the light diffusing agents 131 and 141 are in the above range, good functional layers 130 and 140 may be obtained.

The light diffusing agents 131 and 141 may be used in an amount of about 0.5 parts by weight to 25 parts by weight based on 100 parts by weight of the transparent resin used for the functional layers 130 and 140. When the light diffusing agents 131 and 141 are included in the above ranges based on the above criteria, the light diffusing plates 100b of good quality having excellent light dispersion efficiency can be obtained.

If necessary, the functional layers 130 and 140 may further include at least one selected from ultraviolet absorbers, heat stabilizers, antioxidants, antistatic agents, fluorescent brighteners, and release agents as described in the base layer 110.

The functional layers 130 and 140 may be formed by applying a coating method to at least one of the light incident surface 111 or the light exit surface 112 of the pattern 120, or manufactured in a sheet form. It can be formed by a method of bonding, which can be easily carried out by those skilled in the art. Particularly preferably, the functional layers 130 and 140 may be formed through an extrusion process or a coating process.

According to the present invention, it is preferable that roughnesses 132 and 142 are further formed on at least one surface of the light incident surface 111 of the base layer 110 or the light exit surface 112 of the pattern 120. The roughness 132 and 142 may include the functional layers 130 and 140 to include light diffusing agents 131 and 141 so that predetermined roughnesses 132 and 142 may be naturally formed. The roughness 132 and 142 serves to diffuse light. In addition, the roughness 132, 142 to cancel the light to cancel the image of the lamp to obtain a uniform image.

In general, when a scratch is generated on the light diffusion plate, light may not be diffused normally, thereby degrading the quality of the liquid crystal display. In order to prevent this, a protective film is additionally required. However, when the predetermined roughnesses 132 and 142 are formed as in the present invention, light may be prevented from being deteriorated due to the diffusion of light due to the predetermined roughnesses 132 and 142. As a result, there is no need to add a protective film, thereby preventing cost increases.

In more detail, the roughness 132 and 142 herein refers to the degree of minute unevenness occurring on the surfaces of the functional layers 130 and 140. Representative values can be represented by the centerline average roughness (Arithmetic average roughness, centerline average roughness), which is the average height from the centerline to the cross-sectional curve.

The center line average roughness Ra value of the predetermined roughness 132 formed on the functional layer 130 formed on the light incident surface 111 is not limited, but may be in a range of about 1 μm to 20 μm. Preferably, the centerline average roughness Ra is 3 µm to 15 µm. When the center line average roughness Ra of the functional layer 130 is less than 3 μm, light cannot be diffused, and when a scratch occurs, it is easily identified with the naked eye, so that the quality of the liquid crystal display device may be degraded and productivity may be reduced. In addition, when the center line average roughness Ra of the functional layer 130 exceeds 15 μm, light may not be evenly diffused, and thus the quality of the liquid crystal display may be degraded.

By forming a predetermined roughness 132 in a predetermined range on the functional layer 130 of the light incident surface 111 as described above, it is possible to provide a light diffusion plate 100b that is strong against scratches and has good light efficiency. Of course, by providing a light diffusion plate 100b resistant to scratches as described above, the light diffusion plate 100b according to the present invention does not need to attach a protective film to the light incident surface 111 of the base layer 110. In other words, when the centerline average roughness Ra is less than 3 µm, scratches are more likely to occur, and when scratches occur, quality degradation may occur. Therefore, in order to prevent this, a protective film may be attached to prevent quality deterioration. However, attaching a protective film causes a cost increase. However, when a predetermined roughness 132 having a center line average roughness Ra of 3 μm or more is formed on the light incident surface 111 of the base layer 110 as in the present invention, a light diffusion plate that is resistant to scratching without attaching a protective film 100b will be provided. This means that it is possible to prevent the cost increase by helping to improve the quality of the backlight unit liquid crystal display device or general lighting device.

In addition, roughness 142 may be formed on the light exit surface 112. If a predetermined roughness 142 is formed on the light exit surface 112, the light diffusion efficiency may be further increased. In addition, by forming a predetermined roughness 142, it is possible to prevent a decrease in visibility when a scratch is generated, it is possible to provide a light diffusion plate 100b of excellent quality. Of course, by providing the light diffusion plate 100b resistant to scratches, no protective film is required on the uppermost surface, and therefore, the cost increase can be suppressed. Therefore, the backlight unit and the liquid crystal display device employing the light diffusion plate 100b may also prevent cost increase.

The method of forming the roughness 132, 142 on the light incident surface 111 or the light exit surface 112 allows the roughness 132, 142 to be naturally formed by the light diffusing agents 131 and 141 added to the functional layers 130 and 140, or After the functional layers 130 and 140 are formed, the roughness 132 and 142 may be formed through additional processes. For example, although not shown in the drawings, roughnesses 132 and 142 may be formed by using a shape roll having a predetermined roughness, which is formed by engraving a roll surface using a laser whose energy is controlled, or by using a fine ball-shaped metal. Can be produced by spraying on a roll.

8 is a plan view of a light diffusion plate according to another embodiment of the present invention.

As shown in FIG. 8, the light diffusion plate 200 includes a base layer 210 and a plurality of patterns 220 arranged in a lattice shape on the base layer 210.

The base layer 210 and the pattern 220 are as described above, except that the pattern 220 is formed in an intaglio shape recessed downward on the base layer 210. As described above, even when the pattern 220 formed on the base layer 210 of the light diffusion plate 200 is formed in an intaglio shape, the lamp image is identified when applied to the backlight unit as the pattern is formed in the above embossed shape. Not only can the phenomenon be minimized, the luminance uniformity is high, and it is resistant to scratches, and thus does not require a separate protective film.

The backlight unit according to the present invention includes the light diffusing plate according to the present invention described above. In addition, the liquid crystal display according to the present invention includes the backlight unit and the light source.

The backlight unit may be used in both a direct type and an edge type, but is preferably applied to the direct type.

The light source may be used without limitation, such as a hot cathode tube, a cold cathode tube, a light emitting diode (LED), an organic electroluminescent element (OLED), and the like. Preferably LEDs can be used. Typically, the LED uses a lens type LED as shown in FIG. 9A and a normal type LED shown in FIG. 9B.

The liquid crystal display device may be a reflection type, transmissive type, transflective type LCD, or a liquid crystal display device having various driving methods such as TN type, STN type, OCB type, HAN type, VA type, IPS type, and the like. Since it is well known in the art, detailed description thereof will be omitted.

The lighting apparatus according to the present invention includes the light diffusing plate and the light source according to the present invention described above. The lighting device is not particularly limited, and any lighting device known in the art may be applied and included in the present invention. As the light source of the lighting device, a hot cathode tube, a cold cathode tube, a light emitting diode (LED), an organic electroluminescent element (OLED), or the like may be used without limitation. Preferably LEDs can be used. Since the configuration of the lighting device is well known in the art, a detailed description thereof will be omitted.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, these are presented to aid the understanding of the present invention, and the present invention is not limited thereto.

<Production Examples 1 to 5>

As described in Table 1, using a composition consisting of a transparent resin and a light diffusing agent (size: 5㎛) to form a base layer having a pattern on the surface, the bottom and top of the base layer as shown in Table 1 The base resin was applied to the thickness to form a functional layer.

division Diffusion Base Layer Functional layer Base resin Light diffusing agent Thickness (mm) Base resin Thickness (mm) PC (part by weight) PMMA (parts by weight) PC (part by weight) Preparation Example 1 100 - 1.9 100 0.05 Production Example 2 100 0.5 1.9 100 0.05 Production Example 3 100 1.0 1.9 100 0.05 Preparation Example 4 100 2.5 1.9 100 0.05 Preparation Example 5 100 3.5 1.9 100 0.05

<Examples>

In Preparation Examples 1 to 5, the pattern has a shape as shown in FIGS. 1 to 6, in particular, in FIG. 5, P is 300 μm, p1, p2, and p3 is 50 μm, and h is 303.95 μm, h1. The light-diffusion plate was manufactured so that 160.63 micrometers of silver, 97.96 micrometers of h2, 45.36 micrometers of h3, 70 degrees of (theta) 1, 60 degrees of (theta) 2, and 60 degrees of (theta) 3.

Comparative Example 1

In the Production Examples 1 to 5, a light diffusion plate` without a pattern formed on the substrate layer was manufactured.

Comparative Example 2

In the Production Examples 1 to 5, a light diffusion plate having an elliptical three-dimensional protrusion having a bottom diameter of 250 µm and a height of 160 µm in a lattice shape in an embossed shape was prepared on a substrate layer.

Comparative Example 3

In the Production Examples 1 to 5, a light diffusing plate was prepared in which microlenses (cylindrical protrusions having a diameter of 100 μm and a height of 50 μm) were arranged in a zigzag shape.

Experimental Example 1

After attaching the light diffusing plate manufactured as in Example and Comparative Example to the 42-inch backlight unit, brightness and uniformity were measured as follows, and the results are shown in Tables 2 and 3 below. In this case, the light source is a result of measuring using a normal type LED.

-Luminance and uniformity test

A light diffuser plate was mounted on a 42-inch backlight unit and measured with a luminance meter (RISA-COLOR8, HI-LAND).

Luminance was determined by the tread of the emitted light per unit area (cd / m2), and uniformity was determined by the ratio of the lightest and darkest parts (uniformity (%) = (minimum luminance / maximum luminance) * 100). Judgment on the measurement can be used as the maximum luminance / minimum luminance and the criteria can be applied in the same manner without being different.

At this time, the distance between the light source (LED) and the diffusion plate was set to 10mm, the spacing between the light source was adjusted to 15mm each.

Luminance in nit Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Preparation Example 1 878 879 878 832 Production Example 2 827 842 730 748 Production Example 3 753 820 671 712 Preparation Example 4 667 796 617 659 Preparation Example 5 621 734 574 589

Uniformity (Unit:%) Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Preparation Example 1 13 0 11 12 Production Example 2 45 6 40 37 Production Example 3 62 19 57 48 Preparation Example 4 74 43 62 60 Preparation Example 5 74 54 69 66

In the case of using a normal type LED as a light source, as shown in Table 2 and Table 3, it can be seen that the light diffusing plate according to the present invention has excellent luminance and uniformity as compared to other conventional light diffusing plates. In particular, it can be confirmed that the uniformity is very excellent. Accordingly, even when the distance between the diffusion plate and the light source is close, it can be seen that the diffusion performance is excellent and slim.

Experimental Example 2

Except for using a lens type LED instead of a normal type LED as a light source was carried out in the same manner as in Experiment 1 to measure the brightness and uniformity and the results are shown in Table 4 and Table 5.

Luminance in nit Shape Comparative Shape 1 Comparative Shape 2 Comparative Shape 3 Preparation Example 1 535 226 501 530 Production Example 2 695 300 684 572 Production Example 3 704 395 690 615 Preparation Example 4 681 549 597 662 Preparation Example 5 689 692 685 672

Uniformity (Unit:%) Shape Comparative Shape 1 Comparative Shape 2 Comparative Shape 3 Preparation Example 1 40 0 33 38 Production Example 2 55 6 51 44 Production Example 3 65 23 64 54 Preparation Example 4 75 48 74 66 Preparation Example 5 80 54 78 62

When the lens type LED is used as the light source, as shown in Table 4 and Table 5, it can be seen that the light diffusing plate according to the present invention has excellent luminance and uniformity as compared to other conventional light diffusing plates. In particular, it can be confirmed that the uniformity is very excellent.

Experimental Example 3

Using the light diffusing plate manufactured as in Example and Comparative Example, the scratch resistance and a lamp image visual test were performed as shown below, and the results are shown in Table 6 below.

-Scratch resistance

Using a steel wool tester (WT-LCM100, Korea Protec Co., Ltd.), reciprocating twice under 1.0Kg / 4cm 2 to test scratch resistance, and evaluated according to the following criteria. At this time, steel wool used # 0000 (Test Cycle: 2 Times, Load: 250g / ㎠ (1.0kg / ㎠)).

◎: No scratch

○: Scratched but not visible

×: scratches and visually recognized

-Visual test of lamp image

A visual diffuser plate was mounted on a 42-inch backlight unit to measure visual inspection. In this case, a light source was used as a normal type LED, the distance between the light source (LED) and the diffusion plate was set to 10mm, the spacing between the light source was adjusted to 15mm each.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Scratch resistance Lamp image Scratch resistance Lamp image Scratch resistance Lamp image Scratch resistance Lamp image Preparation Example 1 ○ Good × Bad ○ Bad ○ Bad Production Example 2 ○ Good ○ Bad ○ Good ○ Good Production Example 3 ○ Good ○ Bad ○ Good ○ Good Preparation Example 4 ○ Good ○ Good ○ Good ○ Good Preparation Example 5 ○ Good ○ Good ○ Good ○ Good

As shown in Table 6, the light diffusion plate according to the present invention can be seen that the scratch resistance is excellent and the lamp image visual test results are also good.

1 is a perspective view of a light diffusing plate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the light diffusion plate illustrated in FIG. 1.

3 is a perspective view of the pattern shown in FIG. 1.

4 is a plan view of the pattern shown in FIG.

5 is a side cross-sectional view of the pattern shown in FIG. 1.

6 is a cross-sectional view of a light diffusing plate according to another embodiment of the present invention.

7 is a cross-sectional view of a light diffusing plate according to another embodiment of the present invention.

8 is a plan view of a light diffusion plate according to another embodiment of the present invention.

9A illustrates a lens type LED light source, and FIG. 9B illustrates a normal type LED light source.

<Explanation of symbols for the main parts of the drawings>

100, 100a, 100b, 200: light diffusion plate 110, 210: base material layer

111: light entrance plane 112: light exit plane

113, 131, and 141: light diffusing agents 120 and 220; pattern

130, 140: functional layer 132, 142: roughness

Claims (20)

A base layer having a light incidence surface into which light from a light source is incident on a bottom surface thereof, and a light emission surface on which the light exits from the outside, the plurality of patterns being arranged in a lattice shape; The pattern is: a light diffusing plate, characterized in that the bottom surface is a polygonal, polygonal pyramidal shape consisting of at least three layered structure in which the lower inner corner of the side cross-section is gradually reduced. The method according to claim 1, The pattern is a light diffusing plate, characterized in that the bottom surface is a polygon, a polygonal pyramid consisting of the first layer, the second layer and the third layer of the lower end of the side cross-section gradually decreases. The method according to claim 2, The pattern is a light diffusing plate, characterized in that the bottom surface is square, and the length of one side is P, wherein P is 100 µm to 350 µm. The light diffusing plate of claim 2, wherein the height h of the pattern is 50 μm to 500 μm. The light diffusion plate according to claim 2, wherein when the height of the first layer is h1, the height of the second layer is h2, and the height of the third layer is h3, h1> h2> h3. The method according to claim 1, And another pattern adjacent to the pattern is continuously connected without a separation distance. The light diffusing plate of claim 1, wherein a space between the pattern and another adjacent pattern is spaced apart from each other, and the separation distance c is 0.1 μm to 20 μm. The light diffusing plate of claim 1, wherein the pattern is formed in an embossed shape protruding upward from the base layer. The light diffusing plate of claim 1, wherein the pattern is formed in an intaglio shape recessed downward on the substrate layer. The light diffusing plate according to claim 1, wherein roughness is further formed on at least one of the light incidence plane and the light outgoing plane of the pattern of the base layer. The light diffusing plate according to claim 1, wherein the functional layer is further provided on at least one of the light incidence planes or the light exit planes of the pattern. The light diffusing plate according to claim 11, wherein at least one of the base layer and the functional layer is made of a transparent resin and a light diffusing agent. The light diffusing plate of claim 12, wherein at least one of the base layer and the functional layer comprises at least one selected from a UV absorber, a heat stabilizer, an antioxidant, an antistatic agent, a fluorescent brightener, and a release agent. . A backlight unit comprising the light diffusion plate of any one of claims 1 to 13. An illuminating device comprising the light diffusing plate of claim 1 and a light source. The illuminating device according to claim 15, wherein the light source is an LED. The illuminating apparatus according to claim 16, wherein the LED is a lens type. A liquid crystal display device comprising the backlight unit of claim 14 and a light source. 19. The liquid crystal display device according to claim 18, wherein the light source is an LED. 20. The liquid crystal display device according to claim 19, wherein the LED is a lens type.

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