KR100702634B1 - Light guide plate for liquid crystal display device and high brightness back light unit using same - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a light guide plate for a liquid crystal display device and a high brightness backlight unit using the same to simplify manufacturing and to effectively reduce luminance unevenness and bright lines in a backlight unit using an LED as a light source, and to have a directivity of light. It has its features.

In addition, the present invention improves the brightness and uniformity of the light uniformity to spread the light beam in the plane by reducing the bright line to maximize the satisfaction, such as to suitably apply to products such as liquid crystal panel for large LCD display The present invention provides a light guide plate for a device and a high brightness backlight unit using the same.

To this end, in the present invention, all the intervals of the prism are made the same by using the reflective pattern processed at uniform intervals in two axes, and the light source is incident in a direction parallel to the incident surface, so that the distance between the pitches is intaglio and embossed. All of them achieve the same pitch and distance, and the emission angle of the light source can be made constant, and the high brightness can be realized by emitting at a desired angle by the diffusion sheet and the prism sheet provided on the upper surface of the light guide plate.

LCD, LCD, LGP, Backlight Unit, Prism Sheet, Inverted Prism Sheet, Reflective Pattern

Description

LIGHT GUIDING PLATE FOR LIQUID CRYSTAL DISPLAY DEVICE AND BACK LIGHT UNIT THEREOF}

1 is an exemplary view for explaining a light guide plate according to the present invention;

Figure 2 is another embodiment showing a state in which the lower side of the light guide plate according to the present invention protruding from the side,

3 is an exemplary view extracting a part of a reflective pattern formed on the lower surface of the light guide plate according to the present invention;

4 is an exemplary view showing a triangular form of a reflection pattern horizontal to the incident surface of the light guide plate according to the present invention;

5 is an exemplary view showing an isosceles triangle shape of a reflection pattern perpendicular to the incident surface of the light guide plate according to the present invention;

6 is a planar view showing a lower side of the light guide plate of the present invention;

7 is an exemplary view of a backlight unit to which a light guide plate implemented by the present invention is applied;

8 is another embodiment of the backlight unit to which the light guide plate and the anti-prism sheet applied according to the present invention are applied.

9 is a graph showing luminance values measured for each point using a conventional LGP and the LGP of the present invention.

<Description of the code | symbol about the principal part of drawing>

10: light guide plate 11: upper side

11-1: isosceles triangle 12: lower side

12-1: Reflective pattern 20: Diffusion sheet

30: prism sheet 40: inverse prism sheet

100: backlight unit

The present invention relates to a light guide plate for a liquid crystal display device and a high brightness back light unit using the same.

More specifically, by using the reflective pattern on the lower surface of the light guide plate processed at even intervals in two axes, all the intervals of the prism are made equal, and the light source is incident in a direction parallel to the light incident surface, so that the relatively wide pitch distance is negative. By forming the same pitch and / or both and the same angle, and the exit angle of the light source can be made constant so as to emit at a desired angle by the diffusion sheet and / or (reverse) prism sheet provided on the upper surface of the light guide plate, The present invention relates to a light guide plate for a liquid crystal display device and a backlight unit using the same, to simplify manufacturing, to effectively reduce luminance unevenness and bright lines in a backlight unit using an LED as a light source, and to direct light rays. .

In general, the conventional prism pattern technology of the light guide plate has a prism shape which is processed only in one direction. In the case of such a prism pattern, light can be emitted only in the horizontal or vertical direction with respect to the light source. Consists of an angle and irregular intervals, the pattern is made of a shape in which the individual patterns are formed in a pyramid shape, not an isosceles structure, and the prism pattern is processed in the x and y directions.

Accordingly, the prism pattern is difficult to adjust the uniformity, and the bright lines are generated so that the function of the light guide plate for the backlight unit cannot be smoothly performed, and thus many films of other members are required.

In addition, the reflective pattern of the light guide plate that is being released as a product uses a diffuse reflective pattern of a method of printing a dot or directly injecting it using a stamper. However, as the demand for high brightness increases, the reflective pattern of a prism type is used. It is a situation that the technique of improving the light directivity is disclosed. In particular, the prism-shaped reflection pattern tends to have a structure in which the structure is arranged in a straight line in a specific direction and the structure is arranged in a direction orthogonal to each other.

That is, in Japanese Patent Application Laid-open No. Hei 10-260650 among the previously applied techniques, a plurality of grooves are formed so that the arrangement of the prism is parallel to the longitudinal direction of the light source, and the spacing of the grooves is made smaller as the distance from the light source, Although it is composed of an isosceles triangular prism array on the upper surface, it can be seen that most rays are concentrated at a certain distance from the light guide plate. In Japanese Patent Laid-Open No. 11-24586, one side of the upper or lower surface of the light guide plate is disclosed. Square pyramids are formed at different distances and sizes, but it can be seen that the light beams are intensively emitted at a constant distance as described above.

In the case of the inclined optical axis lens disclosed in Korean Patent Laid-Open Publication No. 2005-68270, a metal thin film coating was formed on a biaxially processed lens to increase the reflectance, but there is a problem in that the light beam does not show directivity due to the optical axis. .

Such a pyramid pattern having a structure to be practiced in the prior art has a structure that continues to increase in density and the prism size is variable, which makes it difficult to form a prism, and in this case, many problems arise in processing the pyramid plane. For example, the problem that the height of the prism acid becomes inconsistent and the processing surface are different from each other cause the problem of deterioration in brightness and uniformity.

Accordingly, the conventional technique has a problem in that a bright line is not generated because the overall light uniformity is not achieved, and the quality of the surface light source for the light guide plate is deteriorated due to the problem in which the bright line is generated. In this incident process, since most of the light beams have a straightness, the light beams do not spread widely due to a problem in which a bright line is generated. Therefore, the light loss in the liquid crystal panel increases, resulting in a decrease in luminance and a decrease in light uniformity.

The bright lines are generated because the light beams are not uniformly formed. This is caused by the formation of a thick line on the portion where the light beams are strong on the liquid crystal panel.

In particular, as described above, since non-uniform light rays are incident on the liquid crystal panel, it is difficult to obtain high uniformity, which is not suitable for a large area liquid crystal panel.

Therefore, due to the above problems, the conventional high brightness light guide plate and the backlight unit manufactured by applying the same have limitations in efficiency such as poor brightness and light uniformity, and thus are not suitable for products such as liquid crystal panels. The problem of not having reliability is implied.

The present invention was created to solve various problems of the prior art as described above, and has the following object.

According to the present invention, all the intervals of the prism are made equal by using the reflective patterns processed at uniform intervals in two axes, and the light source is incident in the direction parallel to the incident surface, so that the distance between the relatively wide pitch is the same in both the intaglio and the indent And a light guide plate for a liquid crystal display device and a high brightness backlight unit using the same to achieve a distance, and to emit a light source at a desired angle by allowing the emission angle of the light source to be constant. There is a purpose.

Another object of the present invention is a light guide plate for a liquid crystal display device and a high brightness backlight unit using the same to simplify manufacturing, to effectively reduce luminance non-uniformity and bright lines in a backlight unit using an LED as a light source, and to make a light beam direct. To provide.

Another object of the present invention is to improve the brightness and uniformity of the light uniformity to spread the light beam in the plane by reducing the bright line to maximize the satisfaction such as suitably applied to products such as liquid crystal panels for large LCD display A light guide plate for a liquid crystal display device and a high brightness backlight unit using the same are provided.

Hereinafter, with reference to the accompanying drawings for a preferred embodiment for achieving the present invention will be described in detail.

In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted, and the following terms will consider functions in the present invention. The terminology set forth herein may vary depending on the intention or convention of users, workers, and producers, and the definition should be made based on the contents throughout the specification.

That is, the present invention is a light guide plate in which a prism pattern is formed on the upper side of the light guide plate as the light emitting surface and the lower side of the light guide plate as the reflective surface, wherein the upper side of the light guide plate has an isosceles triangle, and the lower side of the light guide plate It has a triangular pyramid-shaped reflection pattern formed by a horizontal triangular groove perpendicular to the light incident surface of the ray.

Accordingly, the isosceles triangle formed on the upper side of the light guide plate has a vertex angle of 85 ° or more and 115 ° or less, and the reflective pattern formed in the shape of a square pyramid formed on the lower side of the light guide plate has a bottom side when the triangle is horizontal to the light incident surface. The angle of one side is made of 1 ° or more and less than 10 °, and the other side of the base is made of 10 ° or more and 50 ° or less.

In addition, the reflective pattern formed in the shape of a square pyramid formed on the lower side of the light guide plate is an isosceles triangle in the case of a triangle perpendicular to the light incident surface, and has a vertex angle of 70 ° or more and less than 110 ° and an angle of the bottom side of 30 ° or more and 60 ° or less. It is done.

In this case, the reflective pattern is formed of a groove having a quadrangular pyramid shape or one selected from a shape protruding in a quadrangular pyramid shape.

In addition, a plurality of square pyramid-shaped grooves are formed on the lower side of the light guide plate, which is the reflective surface, and the distance between the pitches and the width of the bottom side are the same in all parts regardless of the size of the light guide plate. The height of the isosceles triangle formed on the side surface is 0.1 μm or more and 100 μm or less, and the depth of the triangular shape formed on the lower side of the light guide plate is 0.1 μm or more and 15 μm or less.

On the other hand, in the backlight unit is applied to the liquid crystal display device to evenly project the light source from the rear of the liquid crystal panel, the backlight unit is made of a reflection pattern in the form of a square pyramid on the lower side, for condensing and reflecting on the upper side It consists of a light guide plate having a triangular shape, and a diffusion sheet and a prism sheet on the upper surface of the light guide plate, and thus the prism sheet has a vertex angle of 70 ° to 120 °.

In addition, the backlight unit is applied to the liquid crystal display device so as to evenly project the light source from the rear of the liquid crystal panel, the backlight unit is formed of a reflection pattern of a square pyramid shape on the lower side, for condensing and reflection on the upper side It consists of a light guide plate having a triangular shape and an inverted prism sheet on the upper surface of the light guide plate, and thus the inverted prism sheet has a vertex angle of 50 ° to 75 °.

In addition, the backlight unit is applied to the liquid crystal display device so as to evenly project the light source from the rear of the liquid crystal panel, the backlight unit is formed of a reflection pattern of a square pyramid shape on the lower side, for condensing and reflection on the upper side The light guide plate has a triangular shape, and only the diffusion sheet is laminated on the upper surface of the light guide plate.

EXAMPLE

With reference to the accompanying drawings, a preferred embodiment for achieving the present invention will be described in detail.

First, the present invention is shown in the accompanying drawings, Figures 1 to 8, Figure 1 is an exemplary view for explaining a light guide plate according to the present invention, Figure 2 is a state in which the lower side of the light guide plate according to the present invention protrudes 3 is a view showing an example of a portion of a reflective pattern formed on the lower surface of the light guide plate according to the present invention, and FIG. 4 is horizontal with respect to the incident surface of the light guide plate according to the present invention. 5 is an exemplary view showing a triangular shape of a reflective pattern, FIG. 5 is an exemplary view showing an isosceles triangular shape of a reflective pattern perpendicular to the incident surface of the light guide plate according to the present invention, and FIG. 6 is a view of the light guide plate implemented according to the present invention. 7 is a plan view showing a lower side, and FIG. 7 is an exemplary view of a backlight unit to which a light guide plate implemented by the present invention is applied, and FIG. 8 is a light guide implemented by the present invention. And a prism sheet is an exemplary view showing another embodiment of the backlight unit is applied.

That is, according to the present invention, the upper side 11 of the light guide plate 10 having the prism pattern formed on the upper side 11 of the light guide plate 10 which is the light emitting surface and the lower side 12 of the light guide plate 20 which is the reflective surface, respectively. Is a structure having a prism pattern of an isosceles triangle 11-1 elongated in one direction, and the lower surface 12 of the light guide plate 10 has a plurality of triangles perpendicular to the horizontal triangle with respect to the light incident surface of the light guide plate. Square pyramidal reflection patterns 12-1 are formed in a cross-aligned structure.

In addition, the reflective pattern 12-1 may be formed of a groove having a square pyramid shape as shown in FIG. 1, or any one of a shape protruding in a square pyramid shape as shown in FIG. 2.

The isosceles triangle 11-1 formed on the upper surface 11 of the light guide plate 10 has a vertex angle α of 85 ° or more and 115 ° or less, and a lower side 12 of the light guide plate 10. The reflective pattern 12-1 formed in the shape of a square pyramid is a triangular shape in which one side angle is smaller than the opposite side angle when the triangle is horizontal with respect to the light incident surface, and one angle β of the base side is less than 1 ° but less than 10 °. And the other angle γ of the base side is made 10 ° or more and 50 ° or less. In addition, the reflective pattern 12-1 formed in the shape of a square pyramid formed on the lower surface 12 of the light guide plate 10 is an isosceles triangle in the case of a triangle perpendicular to the light incident surface, and its vertex angle δ is 70 At least 110 ° and at the base side, the angle ε is made up of 30 ° or more and 60 ° or less.

In addition, the lower surface 12 of the light guide plate 10, which is the reflective surface, is formed of a plurality of square pyramid-shaped grooves intersecting with each other, and the distance between pitches and the width of the base at all portions are irrespective of the size of the light guide plate 10. The same, the height h1 of the isosceles triangle 11-1 formed on the upper surface 11 of the light guide plate 10 is 0.1 μm or more and 100 μm or less, and the lower side of the light guide plate 10. The depth h2 of the triangular shape formed at 12 is to be made 0.1 μm or more and 15 μm or less.

The light guide plate 10 is mounted on the backlight unit 100, which is applied to the liquid crystal display device to uniformly project a light source from the rear side of the liquid crystal panel, and a reflective pattern having a square pyramid shape is formed on the lower side 12 and the upper side ( 11 is composed of a light guide plate 10 having a triangular shape for condensing and reflecting, a diffusion sheet 20 and a prism sheet 30 disposed on an upper surface of the light guide plate 10, and thus the prism sheet ( The vertex angle (A) of 30) is made in the range of 70 ° to 120 °.

In addition, the backlight unit 100 includes a light guide plate 10 having a lower surface 12 having a reflective pattern having a rectangular pyramid shape and an upper surface 11 having a triangular shape for condensing and reflecting the light guide plate 10. The inverted prism sheet 40 is disposed on the upper surface of the, and the vertex angle (B) of the inverted prism sheet 40 is made in the range of 50 ° to 75 °.

In addition, the backlight unit 100 includes a light guide plate 10 having a lower surface 12 formed of a reflection pattern having a square pyramid shape, and an upper surface 11 having a triangular shape for condensing and reflecting the light guide plate 10. It can be configured by stacking only the diffusion sheet 20 on the upper surface.

On the other hand, in the configuration of the light guide plate 10 for the liquid crystal display device and the backlight unit 100 using the same according to the present invention can be variously modified and can take various forms. It is to be understood, however, that the present invention is not limited to the specific forms referred to in the above description, but rather includes all modifications, equivalents and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood that.

In the light guide plate 10 of the present invention, a prism pattern is formed on each of the upper side 11 and the lower side 12 of the light emitting surface, wherein the upper side 11 is an isosceles triangle 11-1. ), And the lower surface 12 has a structure of a reflection pattern 12-1 having a square pyramid formed of a triangular groove perpendicular to a horizontal triangular groove with respect to the light incident surface of the light beam.

In addition, the reflective pattern 12-1 may not only be formed as a groove having a quadrangular pyramid shape but also may have a shape protruding in a quadrangular pyramid shape (see FIG. 2).

The isosceles triangle 11-1 formed on the upper surface 11 of the light guide plate 10 has a vertex angle α of 85 ° or more and 115 ° or less.

One angle β of the bottom side of the horizontal triangle with respect to the light incident surface of the reflective pattern 12-1 is made 1 ° or more and less than 10 °, and the angle γ of the bottom side is 10 ° or more and 50 ° or less. Preferably, the triangle perpendicular to the light incident surface of the reflective pattern 12-1 is formed of an isosceles triangle, and the vertex angle δ of the isosceles triangle is 70 ° or more but less than 110 °. The base side angle ε of the isosceles triangle is preferably made 30 ° or more and 60 ° or less.

The formation of the reflection pattern 12-1 as described above is to make the light incident to the light source uniform and to improve the luminance.

In addition, the lower surface 12 of the light guide plate 10 is formed with a plurality of square pyramid-shaped grooves intersecting with each other, regardless of the size of the light guide plate 10, the distance between the pitch and the width of the bottom side is the same. It is done.

The triangular depth h2 formed on the lower surface 12 of the light guide plate 10 is 0.1 μm or more and 15 μm or less, and isosceles triangles 11-formed on the upper side 11 of the light guide plate 10. The height h1 of 1) is made to be 0.1 μm or more and 100 μm or less.

Accordingly, the backlight unit 100 on which the light guide plate 10 is mounted is applied to the liquid crystal display device to evenly project the light source from the rear side of the liquid crystal panel.

That is, the backlight unit 100 includes the light guide plate 10, the diffusion sheet 20, and the prism sheet 30, and the light guide plate 10 has a reflective pattern formed of a square pyramid-shaped groove on the lower surface 12. It is made of a triangular shape for condensing and reflecting the (12-1) and the upper side 11, and the diffusion sheet 20 and the prism sheet 30 is provided on the upper surface of the light guide plate 10, At this time, the vertex angle (A) of the prism sheet 30 is preferably made in the range of 70 ° to 120 °.

In addition, the backlight unit 100 is another embodiment, and the light guide plate 10 is formed in a triangular shape for condensing and reflecting on the upper surface 11 and a reflective pattern formed in a groove having a rectangular pyramid shape on the lower surface 12. In addition, the upper surface of the light guide plate 10 is composed of a reverse prism sheet 40, wherein the vertex angle (B) of the reverse prism sheet 40 is preferably made in the range of 50 ° to 75 °.

In another embodiment, the backlight unit 100 may be configured by stacking only the diffusion sheet 20 on the upper surface of the light guide plate 10.

In order to compare the average luminance of the present invention having the above-described configuration with a conventional light guide plate, the measurement is shown according to the design configuration as shown in Table 1 below.

Contents Design components Average luminance (cd / m ² ) Conventional 1 Bottom: Horizontal pattern (30 °, 3 °) 3808 Conventional 2 Bottom: Horizontal pattern Top: Prism (30 °, 3 °) 5087 Conventional 3 Bottom: Horizontal pattern (60 °, 6 °) 3093 Conventional 4 Bottom: Landscape Pattern Top: Prism (60 °, 6 °) 3652 Invention 1 Bottom: Horizontal pattern + vertical pattern (30 °, 2 °) (vertical angle 100 °) Depth: 3㎛ 5700 Invention 2 Bottom: Horizontal pattern + Vertical pattern (30 °, 2 °) (Top angle 100 °) Depth: 3㎛ Top: Prism 6900 Invention 3 Bottom: Horizontal pattern + vertical pattern (30 °, 2 °) (vertical angle 100 °) Depth: 4㎛ 6754 Inventive 4 Bottom: Horizontal pattern + Vertical pattern (30 °, 2 °) (Top angle 100 °) Depth: 4㎛ Top: Prism 8211

As shown in Table 1, the conventional 1 to the conventional 4 can be confirmed that the average brightness is not very good, so the present invention is a horizontal pattern on the lower surface of the lower surface of the light guide plate 10 (triangular pattern horizontal to the light incident surface) ) And the vertical pattern (triangular pattern perpendicular to the light incident surface), and set the angles (γ, β) and vertex angle (δ) of the base to the shape of the triangle, respectively, and the upper side as necessary to have a desirable structure. Formed in the shape of the prism on the upper surface and at the same time the average value of the brightness tested by adjusting the depth (h2) of the lower surface of the lower surface, it can be seen that the average brightness shown in the present invention 4 of Table 1 according to the In order to implement the present invention, it is understood that the light guide plate is most preferable as the component shown in the present invention 4 of Table 1.

In addition, as shown in Table 1, when not used in the form of a prism on the upper side, it can be seen that the brightness is significantly reduced or reduced, as compared with the above, the upper and lower patterns are used simultaneously It can be clearly seen that the present invention can realize high brightness.

In addition, Figure 9 is a graph measuring the luminance shown in Table 1, which is excellent in the luminance when the luminance value measured for each point is implemented by the configuration of the light guide plate according to the present invention as shown in Table 2 below You can see clearly.

Contents Conventional 1 2 Conventional 3 4 Invention 1 Invention 2 Invention 3 Inventive 4 Point 1 1547.0 4628.0 1679.0 4628.0 5276.0 7369.0 7521.0 8318.0 Point2 1655.0 4832.0 1701.0 4349.0 5739.0 7185.0 7723.0 8743.0 POINT 3 1537.0 4820.0 1596.0 4478.0 5040.0 6961.0 7005.0 9260.0 POINT 4 6792.0 6387.0 5822.0 5162.0 6670.0 7617.0 7458.0 8629.0 POINT 5 6906.0 6702.0 6050.0 4804.0 6796.0 7499.0 7582.0 9307.0 POINT 6 6187.0 6741.0 5963.0 4722.0 6474.0 7020.0 7065.0 9669.0 POINT 7 3076.0 3936.0 1752.0 1760.0 5177.0 6293.0 5369.0 6253.0 POINT 8 3300.0 3842.0 1583.0 1398.0 5229.0 6226.0 5633.0 7108.0 POINT 9 3280.0 3897.0 1693.0 1567.0 4906.0 6001.0 5430.0 6616.0

Unit: (cd / m ² )

As shown in the graph of FIG. 9 and Table 2, both the horizontal pattern and the vertical pattern are formed on the lower surface of the light guide plate, and the angle γ of the bottom side is 30 ° on one side and 2 ° on the other side (β). ), The vertex angle is 100 ° (δ), and the depth (h2) of the triangular groove is 4 μm, and the most desirable luminance is obtained when an elongated isosceles triangular prism pattern is formed on one side. It can be seen that the uniformity of is also excellent.

Finally, since the above limited values are shown to help the understanding of the present invention, it is to be understood that the present invention does not limit the numerical values, and the above limited values belong to the technical scope of the present invention.

As described above, in the present invention, all the intervals of the prism are made equal by using the reflective patterns processed at uniform intervals in two axes, and the light source is incident in a direction parallel to the light incident surface, so that a relatively wide pitch distance is achieved. Both the intaglio and the embossment achieve the same pitch and distance, and the emission angle of the light source can be made constant so that the emission can be made at a desired angle by the diffusion sheet and the prism sheet provided on the upper surface of the light guide plate. And, there is an effect that the nonuniformity of luminance and the bright line in the backlight unit using the LED as a light source, the effect of the directivity of the light beam and the manufacturing of the high-brightness backlight unit can be made possible.

In addition, the present invention improves the brightness and the uniformity of the light uniformity to uniformly spread the light beam by the reduction of the bright line to improve the product satisfaction, such as being suitably applied to products such as liquid crystal panels for large LCD display It can be effective at the same time.

Claims (14)

In the light guide plate in which a predetermined pattern is formed in the upper surface which is the light emission surface, and the lower surface which is the reflection surface, respectively, An upper surface of the light guide plate has an isosceles triangular prism pattern elongated in one direction; On the lower side of the light guide plate, a plurality of quadrangular pyramid grooves or quadrangular pyramidal protrusion-shaped reflective patterns formed by a triangle perpendicular to the light incident surface of the light beam are arranged in succession, and each of the reflective patterns is a triangle horizontal to the light incident surface. The light guide plate for a liquid crystal display device, characterized in that the portion is made of a triangle having an angle (β) of the base side is smaller than the opposite side angle (γ), the triangle portion perpendicular to the light incident surface is an isosceles triangle. The method of claim 1, An isosceles triangle formed on an upper surface of the light guide plate has a vertex angle of 85 ° or more and 115 ° or less. The method of claim 1, A light guide plate for liquid crystal display device, characterized in that the height of the isosceles triangle formed on the upper surface of the light guide plate is 0.1㎛ 100㎛. delete The method of claim 1, The reflective pattern is a light guide plate for the liquid crystal display device, characterized in that any one selected from the shape formed of a square pyramid-shaped groove or protruding in the form of a square pyramid. The method of claim 1, The triangular depth h2 formed on the lower surface of the light guide plate is 0.1 μm or more and 15 μm or less. The method of claim 1, The reflection pattern is one side (β) of the base side of the triangular portion horizontal to the light incident surface is made of 1 ° or more and less than 10 °, one side angle (γ) of the opposite side of the base side is made of 10 ° or more and 50 ° or less Light guide plate for liquid crystal display device characterized by the above-mentioned. The method of claim 1, The reflective pattern is a liquid crystal display device, characterized in that the vertex angle (δ) of the isosceles triangle portion perpendicular to the light incident surface is 70 ° or more and less than 110 °, and the bottom side angle is 30 ° or more and 60 ° or less. Light guide plate. The method of claim 1, And a plurality of square pyramids intersecting each other on the lower side of the light guide plate as the reflective surface, and the distance between the pitches and the width of the base side are the same in all parts irrespective of the size of the light guide plate. In the backlight unit used to be applied to the liquid crystal display device to evenly project the light source from the rear of the liquid crystal panel, The backlight unit, On the lower side thereof, a plurality of square pyramid grooves or square pyramidal projection reflection patterns formed by a horizontal triangle and a vertical triangle with respect to the light incident surface of the light beam are successively intersected and arranged in one direction for condensing and reflecting on the upper side. A light guide plate on which a prismatic pattern is formed; A diffusion sheet and a prism sheet disposed on an upper surface of the light guide plate; Each of the reflective patterns of the light guide plate may be formed by a triangle having a horizontal portion with respect to the light incident surface having a triangle having an angle β on one side of the bottom side smaller than an opposite side angle γ, and a triangle portion perpendicular to the light incident surface. A high brightness backlight unit for a liquid crystal display device, characterized by consisting of isosceles triangles. The method of claim 10, The prism sheet has a vertex angle of 70 ° to 120 ° range, high brightness backlight unit for a liquid crystal display device. In the backlight unit used to be applied to the liquid crystal display device to evenly project the light source from the rear of the liquid crystal panel, The backlight unit, On the lower side thereof, a plurality of square pyramid grooves or square pyramidal projection reflection patterns formed by a horizontal triangle and a vertical triangle with respect to the light incident surface of the light beam are successively intersected and arranged in one direction for condensing and reflecting on the upper side. A light guide plate on which a prismatic pattern is formed; An inverted prism sheet disposed on an upper surface of the light guide plate; Each of the reflective patterns of the light guide plate may be formed by a triangle having a horizontal portion with respect to the light incident surface having a triangle having an angle β on one side of the bottom side smaller than an opposite side angle γ, and a triangle portion perpendicular to the light incident surface. A high brightness backlight unit for a liquid crystal display device, characterized by consisting of isosceles triangles. The method of claim 12, The reverse prism sheet has a vertex angle of 50 ° to 75 ° range, characterized in that the high brightness backlight unit for a liquid crystal display device. In the backlight unit used to be applied to the liquid crystal display device to evenly project the light source from the rear of the liquid crystal panel, The backlight unit, On the lower side thereof, a plurality of square pyramid grooves or square pyramidal projection reflection patterns formed by a horizontal triangle and a vertical triangle with respect to the light incident surface of the light beam are successively intersected and arranged in one direction for condensing and reflecting on the upper side. A light guide plate on which a prismatic pattern is formed; At least one diffusion sheet is laminated on the upper surface of the light guide plate; Each of the reflective patterns of the light guide plate may be formed by a triangle having a horizontal portion with respect to the light incident surface having a triangle having an angle β on one side of the bottom side smaller than an opposite side angle γ, and a triangle portion perpendicular to the light incident surface. A high brightness backlight unit for a liquid crystal display device, characterized by consisting of isosceles triangles.

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