KR101067679B1 - Light Diffusion member - Google Patents

Abstract

The present invention relates to a light diffusion member in which scratches and noise are not generated at the contact portion with the support pin even when the light diffusion member is expanded and contracted.

Description

Light Diffusion member

The present invention relates to a light diffusing member for use in a liquid crystal display.

As the industrial society develops into an advanced information age, the importance of the electronic display device as a medium for displaying and transmitting various information is increasing day by day. CRT (Cathode Ray Tube), which has been widely used in the past, has limitations due to large installation space, which makes it difficult to increase the size. Therefore, such as liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED) and organic EL It is being replaced by various flat panel display devices. Among such flat panel display devices, in particular, in the case of liquid crystal display devices (LCDs), due to the advantages of thin, light, and low power consumption as a technology-intensive device in which liquid crystal and semiconductor technologies are combined, its structure and manufacturing technology have been researched and developed. In addition to the areas where liquid crystal displays have been widely used, such as notebook computers, desktop computer monitors, and portable personal communication devices (PDAs and mobile phones), large-scale technology is gradually exceeding its limitations. It is being used as a new display device that can replace CRT, which is synonymous with display, as it is applied to large TV of TV.

In the liquid crystal display (LCD) device, since the liquid crystal itself cannot emit light, a separate light source is installed at the rear of the device to adjust the intensity of the passing light through the liquid crystal installed in each pixel to realize contrast. do. In more detail, the liquid crystal display device is a device for controlling the light transmittance by using the electrical properties of the liquid crystal material, the uniformity and the directionality is controlled by passing through various functional prism films or sheets by emitting light from the light source lamp on the back of the device Indirect light-emitting display device that implements an image by passing light through a color filter to realize red, blue, green (R, G, B) colors, and controlling the contrast of each pixel by an electric method As a light emitting device that provides a light source, it is an important component for determining image quality such as brightness and uniformity of a liquid crystal display device.

As the light emitting device, a backlight unit (BLU) is widely used, and in general, light emitted from a plurality of light sources, such as a cold cathode fluorescent lamp (CCFL), is sequentially spread on a diffusion plate, a diffusion sheet, and a prism. A sheet such as a sheet is passed through to reach the liquid crystal panel. Here, the diffusion sheet performs a function of obtaining a uniform light intensity over the entire screen, and at the same time concealing a device such as a light source mounted under the diffusion sheet from the front. The prism sheet, on the other hand, performs an optical path control function for causing the light beams from various directions passing through the diffusion sheet to be converted into a range of viewing angle θ suitable for the viewer to recognize the image.

At this time, in order to fix the diffuser plate mounted on the upper part of the light source, support pins are erected between a plurality of light sources, and when the light source is turned on for a long time and then turned off or is kept turned off, the light source is turned on. In this case, the diffusion plate expands and contracts due to the temperature change, or the expansion plate suddenly expands, which causes the support pin used for fixing to be pulled due to the change of the diffusion plate. There was a problem that occurs or noise occurs.

In particular, recently, liquid crystal display devices have been thinned to meet consumer demand. To this end, if the distance between the light source and the diffuser is reduced to reduce the thickness of the backlight unit, the diffuser is more affected by the temperature change according to the state of the light source. In addition, in this case, the gap between the support pin and the diffusion plate is reduced, so that the possibility of friction or noise caused by temperature change may be increased, thereby preventing problems caused by friction with the support pin due to expansion and contraction of the diffusion plate. There is a need for the development of such a member.

Therefore, an object of the present invention is to provide a light diffusion member in which scratches and noise are not generated at the contact portion with the support pin even when the light diffusion member is expanded and contracted.

In addition, the present invention is to provide a light diffusing member having good concealability even if the distance to the light source is narrowed.

In one preferred embodiment of the present invention for this purpose; And a slip layer having a surface friction coefficient of 0.25 or less on at least one surface of the substrate layer.

The light diffusion member according to the embodiment may have a depth of a hole (Hole) generated after the vibration shock test measured by the following method is 15 μm or less.

* How to measure hole depth after vibration shock test

After mounting it on the backlight unit for liquid crystal display panel, fixing it to the vibration shock, test it for 10min at 10Hz and 20min at 60Hz, and then measure the depth of hole formed at the bottom of the light diffusion member at the same position as the support pin at the center of BLU. Microscopy: CARL ZEISS, LSM 5 Pascal) was used to measure the height deviation (Z) of the highest and lowest hole, and the average value was used three times at the same location.

In the above embodiment, the slip layer may have a thickness of 1 ~ 300㎛.

In the above embodiment, one surface of the base layer on which the slip layer is not formed may include a structure layer in which a plurality of three-dimensional structures are arranged.

In the above embodiment, the structural layer has a first section having a curvature k according to Equation 1 below when the longitudinal section of the three-dimensional structure is represented in both directions about the peak and in the coordinates of the x-axis and the y-axis having the peak as a zero point. And, it may be to include a second section having an inclination angle with the base layer on both sides of the first section.

<Equation 1>

(Wherein x and y are nonzero integers and k is rational.)

In the above embodiment, the second section may have an inclination angle of 30 ° to 50 ° or 130 ° to 150 ° based on the base layer.

In the above embodiment, the first section may have a curvature k of 0.05 to 0.30.

In the above embodiment, the three-dimensional structure of the structural layer may have a pitch of 100㎛ ~ 500㎛.

In the above embodiment, the three-dimensional structure of the structural layer may be a height of 25㎛ ~ 300㎛.

In the above embodiment, the length of the bottom side of the longitudinal section in contact with the substrate layer may be 1/3 to 3/5 of the pitch.

In the above embodiment, the three-dimensional structure of the structural layer may be a structure in which the longitudinal section is symmetric with respect to the vertical center line passing through the peak point.

In the above embodiment, the base resin forming the base layer and the resin forming the slip layer may be formed by co-extrusion.

In the above embodiment, the base resin forming the base layer and the structural layer and the resin forming the slip layer may be co-extruded while passing through the pattern roller.

In the above embodiment, the base layer is selected from polyethylene terephthalate resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin and styrene-acrylic copolymer resin, the structural layer is an ultraviolet curable resin or It may be one selected from a polymer resin including a thermosetting resin, and may be formed by coating a resin forming a slip layer.

In the above embodiment, the base resin may be selected from a resin, a polycarbonate resin, a polystyrene resin, a methyl methacrylate resin, an olefin resin in which a polycarbonate resin and a polystyrene resin are mixed at a weight ratio of 1: 9 to 9: 1. have.

In the above embodiment, the resin forming the slip layer may be selected from fluororesin, styrene-butadiene copolymer, wax and rubber.

In the above embodiment, the resin forming the slip layer may be a styrene-butadiene polymer, and may include one or more selected from fluororesin particles, styrene-butadiene copolymer particles, wax particles, and rubber particles.

 In another preferred embodiment of the invention the above light diffusing member; And a prism sheet formed on one surface of the light diffusing member.

In the backlight unit assembly according to the embodiment, the distance between the light source and the light diffusing member may be 2 to 10 mm.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the accompanying drawings.

1 is a longitudinal cross-sectional view of a light diffusing member 100 according to a preferred embodiment of the present invention mounted on top of a light source 50, and FIG. 2 is a view of the light diffusing member according to a preferred embodiment of the present invention. 3 is a longitudinal cross-sectional view of a light diffusing member according to another preferred embodiment of the present invention.

In the drawings, the same reference numerals are used for the same components for convenience, but they do not mean the same composition and shape.

The light diffusing member of the present invention may include a slip layer 30 on one surface or both surfaces of the substrate layer 10. The slip layer 30 is preferably formed on the surface in contact with the support pin 60 for fixing the light diffusing member 100, the surface friction coefficient is 0.25 or less in order to minimize friction with the support pin 60 It may be. Thus, even if the light diffusing member 100 expands and contracts due to heat, scratches or noises are not generated due to the drag phenomenon in a portion in contact with the support pin 60.

In addition, the light diffusing member of the present invention may be that the depth of the hole (Hole) generated after the vibration shock test measured by the following method is 15㎛ or less, so even if a temperature change occurs in accordance with the state change of the light source 50 Scratches or noise due to expansion and contraction of the diffusion member 100 may be minimized.

* How to measure hole depth after vibration shock test

Mounted on the backlight unit for liquid crystal display panel (LC420WUF), fixed to vibration shock (WANGSAN ENGINEERING, WSVT-4000), tested for 10min at 10Hz and 60Hz for vibration, and then diffused light at the same position as the support pin at the center of BLU The depth of the hole formed on the lower surface of the member was measured by using LSM (Laser Scanning Microscopy: CARL ZEISS, LSM 5 Pascal) to measure the height deviation (Z) of the highest and lowest hole. The average value was used by measuring repeatedly.

The slip layer 30 that satisfies the friction coefficient may include a component having a surface friction coefficient of 0.25 or less. For example, the slip layer 30 may be formed of a resin selected from fluororesin, styrene-butadiene copolymer, wax, and rubber. Alternatively, the styrene-butadiene copolymer resin may include one or more selected from fluorine resin particles, styrene-butadiene copolymer particles, wax particles, and rubber particles.

In order to form the slip layer 30, the base layer 10 may be formed first, and then the resin forming the slip layer 30 may be coated to manufacture the base layer 10 or the base layer 10. ) And the resin forming the slip layer 30 may be produced by coextrusion together with the structural layer 20 to be described later.

The slip layer 30 may be manufactured to have a thickness of 1 to 300 μm in consideration of the stability of noise generated by friction with the support pin even after the vibration test evaluation during repeated expansion and contraction or reliability evaluation of the diffusion plate. Can be.

The light diffusing member of the present invention may include the structural layer 20 on the other surface where the slip layer 30 of the base layer 10 is not formed. More specifically, in the light diffusing member of the present invention, the structural layer 20 may include a plurality of three-dimensional structures, and the light-diffusion member of the present invention does not particularly limit the three-dimensional structure, and the peak is viewed in a longitudinal section. The structure may include a first section 2 having a curvature in both the left and right directions, and a second section 1 having an inclination angle with the base layer on both sides of the first section 2.

At this time, the second section (1) is made of a straight line having a predetermined inclination angle (α) with respect to the base layer 10 when the three-dimensional structure is viewed in longitudinal section, the inclination angle (α) is 30 ° ~ 50 ° or It may be 130 ° ~ 150 °.

Meanwhile, the curvature of the first section 2 may satisfy Equation 1 when the three-dimensional structure is represented by a longitudinal section and represented by coordinates having an x-axis and a y-axis having peaks as zero points.

<Equation 1>

(Wherein x, y and k are rational numbers)

A graph showing the shape of curvature according to Equation 1 is shown in FIG. 4.

In the light diffusing member of the present invention, the k value of Equation 1 which is the curvature of the first section 2 may be 0.05 to 0.30.

The light diffusing member of the present invention includes the first section 2 and the second section 1 having the curvature as described above, so that the incident light passes through the light diffusing member and the actual image R and at least one virtual image V. This may occur. That is, the virtual image (V) refers to a sidelobe generated by implementing a small peak by transmitting only about 5 to 15% of the light, and the transmitted lights appear due to overlapping phenomenon. The principle in which the actual image (R) and the virtual image (V) are generated is shown in FIG. 5. This allows the light to be subdivided more efficiently and reliably than in light diffusion through the light diffusing particles in the conventional light diffusing member (Fig. 6).

Therefore, the real image and at least one virtual image may be generated through the light diffusing member of the present invention, thereby providing appropriate concealment without particularly including a light diffusing agent. The light diffusing member of the present invention may have a total light transmittance of 90% or more and a haze of 90% or more based on a thickness of 1.5 mm.

Such a light diffusing member of the present invention is preferably Weber Fraction of 1.0 or less, because it can provide a stable image for subsequent image evaluation.

<Equation 2>

(Wherein Lumi. Is Luminescence)

The first section 2 may have a length a ₂ of the bottom side contacting the substrate layer 10 being 1/3 to 3/5 of the pitch a, that is, both sides of the first section 2. In each of the second sections 1 formed on the substrate, it is preferable that the length a ₁ of the bottom side in contact with the base layer 10 is 1/5 to 1/3 of the pitch a. When the length (a ₂ ) of the bottom side in contact with the substrate layer (10) exceeds 3/5 of the pitch (a), the first section (2) is widened so that the longitudinal section is close to the semicircular shape, and since the interface of the substantial portion is curved, The optical separation effect due to the refraction increases, and the optical separation effect of clearly dividing the virtual image by the hypotenuse of the second section decreases, thereby reducing the overall optical separation effect. In addition, when the length a ₂ of the bottom side in contact with the substrate layer 10 is less than one third of the pitch a, the first section 2 becomes too short and the longitudinal cross section is close to the triangle, so that by the hypotenuse of the second section, The optical separation phenomenon in which the virtual image is clearly divided into two parts is increased, and the optical separation effect due to the refraction of light is reduced, thereby reducing the optical separation effect as a whole.

At this time, the pitch a of the three-dimensional structure of the structural layer 20 is not particularly limited, but is preferably 100 µm to 500 µm, and the height b of the three-dimensional structure constituting the structural layer 20 is particularly limited. Although it is not, it may be 25㎛ ~ 300㎛, which is to take out the maximum lamp concealment effect in consideration of the shape of the pattern and to eliminate the moiré phenomenon with the pattern sheet going up on the upper surface.

The shape of the three-dimensional structure constituting the structural layer 20 is preferably a structure that is symmetrical with respect to the center line in the vertical direction passing through the peak point, but is not limited thereto.

Such light diffusing member 100 of the present invention may be manufactured by co-extrusion. That is, the molten base resin constituting the base layer 10 and the structural layer 20 may be formed by co-extrusion while passing through the pattern roller. That is, as shown in each drawing, the base layer 10 and the structural layer 20 can be simply produced with one type of resin without the distinction of layers. The thickness including the base layer and the structural layer of the extruded light diffusing member may be 0.5 to 2.0 mm. The temperature during extrusion varies depending on the base resin, but is preferably extruded at 200 to 300 ° C. In this case, the base resin is a resin in which a polycarbonate resin and a polystyrene resin are mixed in a weight ratio of 1: 9 to 9: 1, polycarbonate resin, polystyrene resin, olefin resin, methyl methacrylate resin or styrene-acrylic copolymer resin. Etc. can be used. In this case, the polystyrene resin may be a polystyrene resin having heat resistance, and having a glass transition temperature of 110 ° C. or higher measured by a differential scanning calorimeter or DSC. For example, the manufacturer PS Japan, a trade name G9001, or the like may be used. The olefin resin may include a cycloolefin polymer (COP) or a cycloolefin copolymer (COC).

On the other hand, the light diffusing member of the present invention may be formed by coating and curing a crude liquid containing an ultraviolet curable resin or a thermosetting resin on one surface of the substrate layer 10 to form a structural layer 20.

In this case, polyethylene terephthalate resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin, or styrene-acrylic copolymer resin may be used as the base layer, and the curable resin may be used as the structural layer. If it is a light transmissive material, it will not specifically limit. That is, any polymer resin containing a UV curable resin or a thermosetting resin can be used without limitation, for example, unsaturated fatty acid esters, aromatic vinyl compounds, unsaturated fatty acids and derivatives thereof, unsaturated dibasic acid and derivatives thereof, Vinyl cyanide compounds such as methacrylonitrile and the like can be used. At this time, it is possible to adjust the polymer resin to be used in consideration of the refractive index with the substrate layer.

The substrate layer 10 may have a thickness of 10 μm to 1000 μm in terms of mechanical strength, thermal stability, flexibility, and preventing loss of transmitted light, and more preferably 15 μm to 400 μm.

On the other hand, the light diffusing member of the present invention may include light diffusing particles (not shown) in the base layer 10, it is preferable to use a particle diameter of 1 ~ 50㎛, 100 parts by weight of the binder resin It is preferable to include 1 to 40 parts by weight relative to. When the light diffusing particles having such a particle diameter are included in the above content, an appropriate light diffusing effect may be provided while preventing whitening and separation of the particles.

As the light diffusing particles, a plurality of organic particles or inorganic particles may be used. Representative organic particles include methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylamide, methylol acrylamide, glycidyl methacrylate, and ethyl acryl. Acrylic particles of latex, isobutyl acrylate, normal butyl acrylate, 2-ethylhexyl acrylate homopolymer or copolymer; Olefinic particles such as polyethylene, polystyrene and polypropylene; Acrylic and olefin copolymer particles; And multi-layered multicomponent particles, siloxane polymer particles, tetrafluoroethylene particles, etc. formed by forming particles of a homopolymer and then covering the layers with other types of monomers. Examples of the inorganic particles include silicon oxide and aluminum oxide. , Titanium oxide, zirconium oxide, magnesium fluoride and the like. It will be apparent to those skilled in the art that the organic and inorganic particles are merely exemplary, and are not limited to the particles of the organic or inorganic materials listed above, and may be replaced by other known materials as long as the object of the present invention can be achieved. In addition, such a material change is also within the scope of the technical idea of the present invention.

Meanwhile, in the light diffusing member of the present invention, when the structural layer 20 is formed, the surface layer 40 may be further formed on the structural layer 20, and the surface layer 40 may include particles 45. . The surface layer 40 may be formed by the same method as the method of forming the slip layer 30, and the particles 45 may include organic particles or inorganic particles as the light diffusing particles described above, and the base layer It may be the same as or different from the light diffusing particles included in (10). The surface layer 40 preferably contains 1 to 40 parts by weight of particles with respect to 100 parts by weight of the base resin or binder resin, which is advantageous for light diffusion and concealment, and does not reduce the light utilization efficiency while considering the front luminance. will be. Although the thickness of this surface layer 40 is not specifically limited, It is preferable that it is 10-300 micrometers.

The light diffusing member of the present invention may be subjected to an antistatic treatment on one or both surfaces, for example, may include an antistatic agent or may be coated with an antistatic component by spraying or the like.

On the other hand, the present invention can provide a backlight unit assembly including a prism sheet formed adjacent to one surface of the light diffusing member described above.

In the backlight unit assembly of the present invention, the distance d between the light source 50 and the light diffusing member 100 of the present invention may be 2 to 10 mm, which is a distance between the light source and the light diffusing member in the conventional backlight unit assembly. Compared to 13 ~ 17mm, it is considerably reduced, and nevertheless, it provides the same concealability as that of the conventional case. As a result of the expansion and contraction, the light-diffusion member is not scratched or noise is generated due to the drag phenomenon in the area in contact with the support pin 60.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

&Lt; Example 1 >

The polystyrene resin pellets were coextruded at 220 ° C, uniaxial screw diameter 135mm and 60mm, and the total thickness of the light diffusion member was 1.5mm. Fig. 1 shows the curvature k 0.21, the length of the base side (a ₁ ) in contact with the base layer 10 of the second section 1, and the length of the bottom side in contact with the base layer 10 of the first section 2 ( a ₂ ) to form a structural layer in which the unit structures of the shape as shown in FIG. 2 are linearly arranged in a row while passing through the pattern roller to have a thickness of 150 μm.

On the other side of the base layer, a light diffusion member was manufactured by forming a slip layer co-extruded with styrene-butadiene copolymer resin to a thickness of 50 μm.

<Example 2>

In Example 1, a light diffusing member was manufactured in the same manner except that the slip layer was coextruded with a polyvinylidene fluoride (PVDF) fluororesin.

<Example 3>

A light diffusion member was manufactured in the same manner as in Example 1, except that no structural layer was formed.

<Example 4>

After applying the methacrylate resin to the mold such that the unit structure having the shape as shown in FIG. The film was irradiated for 3 seconds, cured, and released from a metal mold to prepare a light diffusing member. The pitch of the structural layer is 300 μm, the height (b) 130 μm, the inclination angle (α) 40 degrees, the curvature (k) 0.21, the length of the base side contacting the base layer 10 of the second section (a ₁ ) 75 It was 150 micrometers in length (a2) of the base side which contact | connects the base material layer 10 of the 1st section ₂ and the micrometer.

On the other side of the base layer, a light diffusion member was manufactured by forming a slip layer co-extruded with styrene-butadiene copolymer resin to a thickness of 50 μm.

Comparative Example 1

In Example 1, a light diffusing member was manufactured in the same manner except that no slip layer was formed.

Comparative Example 2

A light diffusion plate (manufacturer: Kolon, trade name: DP421, thickness: 1.50 mm, transmittance: 57.0%, haze: 99%) was prepared.

Comparative Example 3

Light diffusing sheet (manufacturer: Kolon, brand name: LD613, thickness: 188 μm, transmittance: 75.5%, haze: 96.0%) on the prism sheet (manufacturer: Kolon, brand name: LC213, thickness: 188 μm, pitch: 50 μm, height : 25 µm, inclination angle 45 °) was prepared.

Evaluation of physical properties of optical members, such as the light diffusing members prepared in Examples and Comparative Examples, was carried out in the following manner, and the results are shown in Table 1 below.

(1) surface friction coefficient

Surface friction coefficient (μ) was measured by using a friction coefficient measuring device (AMETEK Co., Ltd. LF Plus), the maximum static friction coefficient (Static Coefficient) value. At this time, the light diffusion member proceeded as in the measuring method ASTM D 1894, and was placed on the upper surface of the base plate of the measuring instrument and attached to the back of the sled (weight: 279gf, size: 63.0 × 68.0 mm). The base plate moving speed was 250 mm / min and the moving distance was 150 mm.

(2) Hole depth measurement after vibration shock test

Vibration shock test is mounted on the backlight unit (LC420WUF) for 42-inch liquid crystal display panel, and fixed to the vibration shock (WANGSAN ENGINEERING, WSVT-4000), and then tested for 10min at 10Hz and 20min at 60Hz.

After the vibration shock test, the depth of the hole formed in the lower surface of the light diffusion member at the same position as the support pin at the center of the BLU was measured by laser scanning microscopy (LSM, LSM 5 Pascal). The height deviation (Z) of the highest and lowest hole was measured, and the average value was used by measuring three times at the same location.

(3) luminance

The light diffusing member in the above Examples and Comparative Examples was mounted on a 42-inch liquid crystal display panel backlight unit (LC420WUF) and fixed at a distance of 4.0 mm using a luminance meter (TOPCON, BM-7). Luminance was measured at 13 points and the average value was obtained.

(4) Heat resistance

The light diffusing members in the above Examples and Comparative Examples were cut into 42-inch sizes, and then fixed in the thermo-hygrostat after standing in the longitudinal direction. At this time, the lifting bending amount of the four corner portions of the light diffusion member before and after the test was placed on the surface plate and measured by a gap gauge, and the average value of the four corner bending amounts was used. The smaller the amount of warpage and the amount of warpage change before and after the test, the higher the heat resistance.

(5) Weber fraction (hidden)

The light diffusing member in the above Examples and Comparative Examples was mounted on a 42-inch liquid crystal display panel backlight unit (LC420WUF) and the distance from the light source was fixed at 4.0 mm to determine the luminance facing meter (MINOLTA, CA-2000). Nessence) was measured, the Weber fraction was calculated by the following formula 2, and the results are shown in Table 1.

<Equation 2>

Wherein Lumi. Is Luminescence.

division Surface friction coefficient
(μ) Hole Depth
(z, μm) Luminance
(cd / ㎡) Heat resistance (mm) Weber fraction (%) Example 1 0.22 4.29 9543 0.10 0.80 Example 2 0.24 4.54 9439 0.11 0.85 Example 3 0.22 4.31 6848 0.11 1.72 Example 4 0.22 4.26 9345 0.15 0.82 Comparative Example 1 0.35 35.81 9545 0.10 0.80 Comparative Example 2 0.30 6.45 6948 0.10 1.33 Comparative Example 3 0.38 18.33 7541 - 1.42

1 is a longitudinal cross-sectional view of a light diffusing member mounted on an upper portion of a light source according to a preferred embodiment of the present invention;

2 is a longitudinal sectional view of a light diffusing member according to a preferred embodiment of the present invention;

3 is a longitudinal sectional view of a light diffusing member according to another preferred embodiment of the present invention;

4 is a graph showing the shape of curvature between the first layer of the structural layer of the light diffusing member according to an embodiment of the present invention;

5 is a view showing a principle that the actual image (R) and the virtual image (V) is generated through the light diffusion member according to an embodiment of the present invention,

6 is a view showing the principle that light is diffused in the conventional light diffusion member.

* Explanation of the symbols of the main parts of the drawings

1: second section 2: first section

10: substrate layer 20: structure layer

30: slip layer 40: surface layer

45 particle 50 light source

60: support pin 100: light diffusion member

Claims (19)

A base layer; And And a slip layer having a surface friction coefficient of 0.22 to 0.25 on at least one surface of the substrate layer. The method of claim 1, Light diffusing member, characterized in that the depth of the hole (Hole) generated in the lower surface of the light diffusing member after the vibration impact test measured by the following method is 15㎛ or less. * How to measure hole depth after vibration shock test After mounting it on the backlight unit for liquid crystal display panel, fixing it to the vibration shock, test it for 10min at 10Hz and 20min at 60Hz, and then measure the depth of hole formed at the bottom of the light diffusion member at the same position as the support pin at the center of BLU. Microscopy: CARL ZEISS, LSM 5 Pascal) was used to measure the height deviation (Z) of the highest and lowest hole, and the average value was used three times at the same location. The method of claim 1, The slip layer is a light diffusion member, characterized in that the thickness is 1 ~ 300um. The method of claim 1, The light diffusing member, characterized in that it comprises a structural layer in which a plurality of three-dimensional structure is arranged on one surface of the base layer, the slip layer is not formed. The method of claim 4, wherein The structural layer has a first section having a curvature (k) according to Equation 1 below when the longitudinal cross-section of the three-dimensional structure is shown in both directions centered on the peak and represented by the coordinates of the x-axis and the y-axis with the peak at zero. And a second section having an inclination angle with the base layer on both sides of the section. <Equation 1>

(Wherein x and y are nonzero integers and k is rational.) The method of claim 5, The second section has a light diffusion member, characterized in that having a tilt angle of 30 ° ~ 50 ° or 130 ° ~ 150 ° with respect to the base layer. The method of claim 5, The first section is a light diffusion member, characterized in that the curvature (k) is 0.05 ~ 0.30. The method of claim 5, The three-dimensional structure of the structural layer is a light diffusion member, characterized in that the pitch is 100㎛ ~ 500㎛. The method of claim 5, The three-dimensional structure of the structural layer is a light diffusion member, characterized in that the height is 25㎛ ~ 300㎛. The method of claim 5, The first section has a light diffusion member, characterized in that the base length of the longitudinal section in contact with the substrate layer is 1/3 to 3/5 with respect to the pitch. The method of claim 5, The three-dimensional structure of the structural layer is a light diffusing member, characterized in that the longitudinal section is a structure symmetric with respect to the vertical center line passing through the peak point. The method of claim 1, A light diffusing member, wherein the base resin forming the base material layer and the resin forming the slip layer are formed by coextrusion. The method of claim 4, wherein A base resin for forming a base layer and a structural layer and a resin for forming a slip layer are coextruded and formed while passing through a pattern roller. The method of claim 4, wherein The base layer is selected from polyethylene terephthalate resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin and styrene-acrylic copolymer resin, The structural layer is selected from a polymer resin including an ultraviolet curable resin or a thermosetting resin, A light diffusing member, wherein the resin forming the slip layer is coated and formed. The method according to claim 12 or 13, The base resin is a light diffusing member, characterized in that the polycarbonate resin and polystyrene resin is selected from a resin, polycarbonate resin, polystyrene resin, methyl methacrylate resin, olefin resin mixed in a weight ratio of 1: 9 ~ 9: 1: . The method according to any one of claims 12 to 14, The resin for forming the slip layer is a light diffusing member, characterized in that selected from fluororesin, styrene-butadiene copolymer, wax and rubber. The method according to any one of claims 12 to 14, The resin for forming the slip layer is a styrene-butadiene copolymer, wherein the resin comprises at least one selected from fluorine resin particles, styrene-butadiene copolymer particles, wax particles and rubber particles. The light diffusing member of claim 1; And And a prism sheet formed on one surface of the light diffusing member. The method of claim 18, A backlight unit assembly with a light source and a light diffusion member having a distance of 2 to 10 mm.

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