KR101038428B1 - Prism sheet, backlight unit and liquid crystal display including the same - Google Patents

Abstract

A prism sheet is provided which divides a prism sheet used in a liquid crystal display into a plurality of zones, and arranges the micro-optic patterns of adjacent zones to cross each other at a predetermined angle.

Such a prism sheet,

A base film having a light transmittance, and an optical pattern layer formed on one surface of the base film and having a plurality of fine optical patterns formed thereon for collecting the light incident from the rear and forwarding the light;

The optical pattern layer is divided into at least two zones, and the micro-optical patterns in each zone have a predetermined cross-section and are continuously arranged in one direction, and each micro-optic pattern between neighboring zones has a predetermined angle. Characterized in that arranged to cross.

Prism Sheet, Base Film, Micro Optical Pattern, Intersecting, Liquid Crystal Display

Description

Prism sheet, backlight unit and liquid crystal display including the same {PRISM SHEET, BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY INCLUDING THE SAME}

The present invention relates to a prism sheet for a liquid crystal display (LCD), and more particularly, to divide the prism sheet used in the liquid crystal display into a plurality of zones, and the micro-optical patterns of the adjacent areas to cross each other at a predetermined angle. A prism sheet arranged to be arranged, and a backlight unit and a liquid crystal display including the prism sheet.

In general, a liquid crystal display (LCD) is a light-receiving device that displays an image by controlling the amount of light coming from the outside, so a separate light source for irradiating light to the liquid crystal display panel, that is, a backlight unit (BLU) Back Light Unit). The backlight unit includes an optical sheet layer for improving front luminance of the liquid crystal display panel. The optical sheet layer includes a diffusion sheet for diffusing light incident from the light guide plate toward the liquid crystal display panel, and a prism sheet disposed in front of the diffusion sheet. The prism sheet diffuses light from the light guide plate to increase a component of light directed toward the front of the liquid crystal display panel.

1 is an exploded perspective view of a general liquid crystal display device.

Referring to FIG. 1, the liquid crystal display device includes a backlight unit 10 and a liquid crystal display panel 20. The backlight unit 10 is typically composed of a light source 11, a reflecting plate 12, a light guide plate 13, a diffusion plate 14, first and second prism sheets 15 and 16 and a protective sheet 17. Light from the light source 11 proceeds to the light guide plate 13, and various patterns such as a fine dot pattern are printed on the bottom surface of the light guide plate 13 so as to direct the traveling direction of the light to the liquid crystal display panel 20. It is. The reflector 12 is disposed at the rear of the light guide plate 13 to reflect the light emitted to the rear of the light guide plate 13 toward the light guide plate 13 to minimize the loss of light. The diffusion plate 14 serves to disperse the light incident from the light guide plate 13, and also serves to reduce the incident inclination angle of the light traveling to the first prism sheet 15. The first prism sheet 15 and the second prism sheet 16 are formed with a plurality of micro optical patterns respectively for condensing incident light on the upper surface and outputting the light to the upper liquid crystal display panel 20. In this case, the microscopic optical patterns of the first prism sheet 15 and the second prism sheet 16 are arranged to be perpendicular to each other. The protective sheet 17 is disposed above the second prism sheet 16 to protect the prism sheet 16.

2 is a structure of a conventional prism sheet.

Referring to FIG. 2, the conventional prism sheet 21 generally includes an prism pattern 23 having an isosceles triangular shape on one surface of the base film 22 and extending all mountains and valleys in one direction. . Accordingly, the prism sheet converges light incident perpendicular to the longitudinal direction of the prism mountains in the normal direction of the prism sheet, but does not collect light incident side by side in the longitudinal direction of the prism mountains. Accordingly, the upper and lower prism sheets are arranged so that the prism mountains are orthogonal to each other in order to focus the light incident in the vertical and horizontal directions of the prism sheet as much as possible. However, this is disadvantageous in price and light weight, there is a problem that the loss of light occurs while passing through the upper and lower prism sheet.

In addition, the prism sheet is damaged by friction with a liquid crystal display panel or another optical sheet disposed in front of the prism acid provided on one side thereof, and thus light such as brightness, moire, and wet-out of the liquid crystal display device. There is a problem that acts as a factor that inhibits the characteristics.

Accordingly, an object of the present invention is to provide a prism sheet capable of improving the light condensing effect of light by improving the arrangement of microscopic optical patterns formed on the prism sheet.

In addition, an object of the present invention is to provide a prism sheet capable of improving front luminance by forming vertical microscopic patterns in different directions on the prism sheet, thereby improving vertical incidence to light in up and down and left and right directions.

In addition, the present invention by forming a plurality of micro-optical patterns that cross or orthogonal to each other in one prism sheet to reduce the manufacturing cost and to reduce the damage of other optical elements during the assembly of the backlight unit to improve the optical properties of the prism The purpose is to provide a sheet.

In addition, an object of the present invention is to provide a prism sheet that can widen the vertical, horizontal and left and right viewing angles by adjusting the area size and the number of patterns of the micro-optic pattern formed on the prism sheet.

Furthermore, another object of the present invention is to provide a backlight unit and a liquid crystal display device including the prism sheet.

An embodiment of the present invention for achieving the above object,

A base film having light transmittance; And

An optical pattern layer formed on one surface of the base film and having a plurality of micro-optical patterns for condensing light incident from the rear and emitting the light toward the front; Including,

The optical pattern layer is divided into at least two zones, and the micro-optical patterns in each zone have a predetermined cross-section and are continuously arranged in one direction, and each micro-optic pattern between neighboring zones has a predetermined angle. It relates to a prism sheet, characterized in that arranged to cross.

In addition, another embodiment of the present invention for achieving the above object,

A light transmitting first base film;

A first optical pattern layer formed on the front surface of the first base film and having a plurality of first fine optical patterns formed thereon for collecting the light incident from the rear and emitting the light forward;

A light transmissive second base film formed on the entire surface of the first optical pattern layer; And

A second optical pattern layer formed on the front surface of the second base film and having a plurality of second fine optical patterns formed thereon for collecting the light passing through the second base film and outputting it forward; Including,

The first and second optical pattern layers are each divided into at least two or more zones, and the micro-optical patterns in each of the zones have a predetermined cross section and are continuously arranged in one direction, and each of the fine zones between adjacent zones is adjacent to each other. Optical patterns are arranged to cross at a predetermined angle,

A prism sheet, wherein the microscopic optical patterns are arranged to be orthogonal to each other between the respective zones of the first optical pattern layer and the respective zones of the second optical pattern layer respectively corresponding to the respective zones of the first optical pattern layer. It is about.

In the present invention, the predetermined angle is preferably 45 degrees or more and 90 degrees or less.

In the present invention, the micro-optic pattern between the adjacent areas are preferably arranged to be orthogonal to each other.

In this case, the micro-optic pattern of the at least one zone may be arranged along the longitudinal direction of the base film, it may be arranged along the diagonal direction of the base film.

In the present invention, it is preferable that the cross section of each of the micro-optical patterns has a shape of any one of a polygon or an arc shape.

In the present invention, the at least one or more zones may vary in size.

In the present invention, the at least one or more zones may have different numbers of microscopic optical patterns.

In addition, the present invention for achieving the above object relates to a backlight unit including any one prism sheet selected from the above embodiments, and a liquid crystal display device comprising such a backlight unit.

According to the present invention, the front luminance of the liquid crystal display can be improved by collecting light in the left and right and up and down directions and emitting the light vertically upward.

In addition, according to the present invention, it is possible to prevent the prism acid from being damaged by friction with the liquid crystal display panel, other optical elements, or the like, and to prevent optical properties such as luminance from being lowered.

Further, according to the present invention, the left, right, and up and down viewing angles can be enlarged in the liquid crystal display.

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

3 is a structure of a prism sheet according to an embodiment of the present invention.

Referring to FIG. 3, the prism sheet 100 according to an exemplary embodiment of the present invention collects a base film 110 having light transmittance and light incident from the rear surface formed on one surface of the base film 110. It is configured to include an optical pattern layer 130 is formed with a plurality of micro-optic pattern 120 for forwarding.

The base film 110 is a material that substantially transmits the light incident from the rear, for example, polycarbonate (PC), polyester (PET: polyester), polypropylene (PP: polypropylene), polyethylene (PE: polyethylene) ), Polymethyl methacrylate (PMMA: Polymethly Methacrylate) may be implemented as one selected from.

The optical pattern layer 130 includes a plurality of micro-optical patterns 120 implemented to condense the light incident from the rear and emit the light toward the front. The micro-optic pattern 120 has a predetermined cross section and is continuously arranged along one direction of the base film 110. Here, the optical pattern layer 130 is divided into at least two or more zones, and the micro optical patterns 120 are arranged to cross each other at adjacent angles. In an embodiment of the present invention, the predetermined angle is preferably 45 degrees or more and 90 degrees or less. As described above, the micro-optic patterns 120 adjacent to each other are arranged to cross each other at a predetermined angle so that the light in the crossed directions can be focused and emitted forward. At this time, more preferably, the micro-optical patterns 120 of the adjacent regions are arranged to be orthogonal to each other. This is because when the micro-optic patterns 120 in the adjacent areas are orthogonal to each other, the front luminance may be improved by concentrating light in the vertical and horizontal directions.

Hereinafter, with reference to FIGS. 3A and 3B, an example in which the micro-optical patterns are arranged to be orthogonal to each other between adjacent areas as an example of the present invention will be described in detail.

In FIG. 3A, the optical pattern layer 130 is divided into four zones, that is, the first to fourth zones 31, 32, 33, and 34, in the horizontal direction. In each of the zones 31 to 34, a micro-optic pattern 120 in which a plurality of mountains and valleys are continuous is formed. At this time, the areas adjacent to each other, that is, between the first zone 31 and the second zone 32, the second zone 32 and the third zone 33, the third zone 33 and the fourth zone 34 The directions of the microscopic optical patterns 120 are orthogonal to each other.

In FIG. 3B, as another example, the optical pattern layer 130 is divided into five sections in the horizontal and vertical directions, respectively, and is divided into a total of 25 zones. The micro-optic pattern 120 in which a plurality of mountains and valleys are continuously formed in each zone is formed, and in this case, the directions of the micro-optic patterns 120 are orthogonal to each other between neighboring zones.

3 illustrates a structure in which the micro optical patterns 120 of at least one region are arranged in the longitudinal direction of the base film 110, but the present invention is not limited thereto. Therefore, as shown in FIG. 4, in another embodiment of the present invention, the micro-optic pattern 120 of at least one region may be arranged in a diagonal direction of the base film 110. Further, although not shown in the drawings, it is obvious that in another embodiment of the present invention may be arranged in other directions. This improves the overall front luminance by condensing and directing the light in the direction according to the arranged direction.

In addition, as in another embodiment of the present invention shown in Figure 5 (ac), each of the zones (31 to 34) may be formed in a different size, the micro-optical pattern 120 of each zone The number of patterns and the cross-sectional shape may be different. In other words, as shown in FIGS. 5A and 5B, the viewing angle can be adjusted by differently forming the number of patterns of the micro-optic pattern 120 for each zone 31 to 34.

For example, in FIG. 5 (a), the area of the vertical pattern increases, so that the left and right viewing angles become narrower, and the upper and lower viewing angles become wider. In FIG. do. In this way, by adjusting the size and number of patterns in each zone, it is possible to adjust the distribution of left and right, up and down viewing angle.

In addition, as shown in FIG. 5C, the cross-sectional shape of the micro-optic pattern 120 may be differently formed in each of the regions 31 to 34. In FIG. 5C, as an example, the cross section of the micro-optic pattern 120 is formed in a triangular shape and an arc shape. However, the present invention is not limited thereto and may be formed in various shapes such as other polygons. In this case, in the case of a triangle, the vertex angle of the light collecting efficiency is preferably in the range of 50 ~ 110 degrees.

6 is a perspective view of a prism sheet according to another embodiment of the present invention.

Referring to FIG. 6, the prism sheet according to the present invention is formed on one surface of the first base film 210 and the first base film 210 having light transmittance, and a plurality of first lights for condensing incident light and emitting the light forward. The first optical pattern layer 230 on which the micro-optic pattern 220 is formed, the second base film 240 having light transmittance formed on the upper surface of the first optical pattern layer 230, and the upper surface of the second base film 240. The second optical pattern layer 260 is formed on the second optical pattern layer 260 formed with a plurality of second fine optical patterns 250 for condensing the incident light to the front.

The first and second base films 210 and 240 are materials that transmit light incident from the rear, for example, polycarbonate (PC), polyester (PET), polypropylene (PP), and polyethylene ( PE: Polyethylene), polymethyl methacrylate (PMMA: Polymethly Methacrylate) may be implemented as one selected from.

The first and second optical pattern layers 230 and 260 include a plurality of first and second micro optical patterns 220 and 250, respectively, which are configured to focus incident light and emit the light forward. The first and second fine optical patterns 220 and 250 have a predetermined cross section and are continuously arranged along one direction of the first and second base films 210 and 240, respectively. Here, the first and second optical pattern layers 230 and 260 are each divided into at least two or more zones, and in the same optical pattern layer, adjacent regions of the first and second optical pattern layers 220 and 250 are respectively defined. It is arranged to intersect at an angle. In one example of the present invention, the predetermined angle is preferably 45 degrees or more and 90 degrees or less. More preferably, the micro-optic patterns 120 and 250 of the regions adjacent to each other are arranged to be orthogonal to each other.

In this case, the first and second optical pattern layers 230 and 260 are preferably divided into the same number of zones, and each of the zones divided by the first optical pattern layer 230 and the second optical pattern layer corresponding to each other ( The micro-optic patterns 220 and 250 are formed to be orthogonal to each other between the zones of 260. In other words, the regions at the same position in the first optical pattern layer 230 and the second optical pattern layer 260 when viewed from above in two prism sheets are formed such that the directions of the micro optical patterns are perpendicular to each other.

Hereinafter, with reference to FIGS. 6A and 6B, an example in which the micro-optical patterns are arranged to be orthogonal to each other between regions adjacent to each other in the same optical pattern layer will be described in detail.

6A illustrates an example in which the first and second optical pattern layers 230 and 260 are divided into four zones, respectively. In each zone 41 to 44 of the first optical pattern layer 230, a first micro optical pattern 220 in which a plurality of mountains and valleys are formed in succession is formed. 41 and the second zone 42, the second zone 42 and the third zone 43, the third zone 43 and the fourth zone 44, the direction of the micro-optic pattern 220 is perpendicular to each other do.

Similarly, the second microscopic optical patterns 250 in which a plurality of mountains and valleys are formed continuously are formed in each of the regions 45 to 48 of the second optical pattern layer 260, and the fifth region 45 which is a neighboring region. ), And the directions of the micro-optic patterns 250 are orthogonal to each other between the sixth section 46, the sixth section 46 and the seventh section 47, and the seventh section 47 and the eighth section 48. .

At this time, the first zone 41 of the first optical pattern layer 230 and the fifth zone of the second optical pattern layer 260 corresponding to the first zone 41, that is, The microscopic optical patterns 220 and 250 are orthogonal to each other between the fifth regions 45 of the second optical pattern layer 260 at the same position as the first region 41 of the first optical pattern layer 230. This relationship applies equally to other areas.

In FIG. 6B, as another example, the first and second optical pattern layers 230 and 260 are divided into 25 zones. The first and second microscopic optical patterns 220 and 250 having a plurality of mountains and valleys are formed in each zone in succession, and the directions of the microscopic optical patterns 220 and 250 are orthogonal to each other between adjacent regions. Furthermore, the micro-optic patterns are formed to be orthogonal to each other in the region at the same position when viewed from the top between the two prism sheets.

6 illustrates a structure in which the micro optical patterns 120 of at least one region are arranged in the longitudinal direction of the base film 110, but the present invention is not limited thereto. Therefore, in another embodiment of the present invention, the micro-optic pattern 120 of at least one region may be arranged in a diagonal direction or another direction of the base film 110. This improves the overall front luminance by condensing the light in the arranged direction and directing it forward.

On the other hand, Figures 3 to 6 shows an example in which the micro-optic pattern between the adjacent areas as the embodiments of the present invention formed to be orthogonal to each other, the present invention is not limited to this, as described above, The microscopic optical patterns may be arranged to intersect at a predetermined angle (eg, 45 to 90 degrees).

7 is a simulation diagram for comparing the brightness of the prism sheet and the conventional general prism sheet according to the present invention, Figure 7 (a) is placed on the diffusion sheet by arranging two conventional prism sheets to be orthogonal to each other after 7B is a simulation diagram of measuring luminance, and FIG. 7B is a simulation diagram of luminance after a prism sheet in which micro-optical patterns between neighboring regions are orthogonal to each other is placed on a diffusion sheet.

As shown in the figure, when comparing the conventional luminance distribution and the luminance distribution of the present invention, the left and right in the case of the present invention appears that the brightness is similar to the conventional, the upper and lower portions of the brightness is slightly compared to the conventional It appears to be falling. Looking at the overall average brightness of both, the conventional brightness is 2,853 nit in the conventional case and 2,786 nit in the present invention. That is, in the case of the present invention, the luminance appears to be about 98% as compared with the prior art. Even in view of such a decrease in luminance, a single prism sheet condenses light in the right and left directions and emits it vertically upward, and prevents the prism acid from being damaged by friction with liquid crystal display panels or other optical elements. There is an effect of preventing deterioration of optical characteristics such as luminance.

On the other hand, the inventors of the present invention repeatedly performed a simulation to measure the brightness while varying the crossing angle of each micro-optic pattern between the adjacent areas in the prism sheet of the present invention. This simulation is to determine how the luminance changes with the crossing angle. Specifically, in FIG. 7 (b), the luminance of the conventional general prism sheet is regarded as 100%, and in the prism sheet according to the embodiment of the present invention, the intersection angle of each micro-optic pattern between adjacent regions is 90 degrees. The luminance at that time was measured while changing from 5 degrees to 35 degrees in units of degrees. The measured brightness is shown in Table 1 below.

Table 1

division Average luminance (nit) percentage 2 sheets of conventional general prism sheet 2,853 100% 90 degree cross angle of the present invention 2,786 98%        〃 85 degrees 2,710 95%        〃 80 degrees 2,651 93%        〃 75 degrees 2,607 91%        〃 70 degrees 2,573 90%        〃 65 degrees 2,512 88%        〃 60 degrees 2,448 86%        〃 55 degrees 2,391 84%        〃 50 degrees 2,337 82%        〃 45 degrees 2,278 80%        〃 40 degrees 2,248 79%        〃 35 degrees 2,170 76%

In the luminance results shown in Table 1 above, when the luminance measured by vertically crossing two conventional prism sheets is assumed to be 100%, the luminance of 80% or more is significantly higher than that of the conventional luminance. It is preferable to maintain the crossing angle of the micro-optical pattern 45 to 90 degrees. In this case, it can be seen that the crossing angle is 90 is the best. Such a crossing angle may be embodied as an embodiment of the present invention when approaching in terms of securing the above-described effects even in view of a slight decrease in luminance in the liquid crystal display. In another embodiment of the present invention, in order to implement the luminance at 90% or more, it may be preferable to implement the crossing angle at 70 degrees.

8 is an exploded perspective view of a liquid crystal display including a prism sheet according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the liquid crystal display device 300 according to an exemplary embodiment may include a liquid crystal display panel 310 displaying an image and a backlight unit 320 that illuminates light toward the liquid crystal display panel 310. It is configured to include. The liquid crystal display panel 310 and the backlight unit 320 may be accommodated by a front casing and a rear casing (not shown).

The liquid crystal display panel 310 displays an image based on the light incident through the backlight unit 320. In the liquid crystal display panel 310, a liquid crystal layer is disposed between two substrates facing each other, and the arrangement of the liquid crystal layers is changed by an electric field formed between the electrodes, thereby controlling the amount of light passing through the liquid crystal layer. As a result, the liquid crystal display device 300 displays an image on the liquid crystal display panel 310.

The backlight unit 320 may include a light source 321 for generating light, a light guide plate 322 for converting light from the light source 321 into a surface light source, and light emitted behind the light guide plate 322 into the light guide plate 322. And a reflecting plate 323 to reflect and an optical sheet layer 324 disposed in front of the light guide plate 322. Here, the protective sheet 327 may be further included in front of the optical sheet layer 324 to protect the optical sheet layer 324.

The light source 321 is disposed in the side portion of the light guide plate 322 by way of example, and generates light to be directed into the light plate 322. Here, the light source 321 may be a point light source such as a light emitting diode (LED), or may be a line light source such as a cold cathode tube.

The light guide plate 322 is disposed behind the liquid crystal display panel 310, and converts light generated from the light source 321 into a surface light source and emits the light toward the liquid crystal display panel 310. The light guide plate 322 is formed of a plastic-based transparent material such as acrylic, and light generated from the light source 321 is emitted toward the liquid crystal display panel 310 disposed in front of the light guide plate 322.

The reflection plate 323 is disposed behind the light guide plate 322 to reflect the light emitted toward the rear of the light guide plate 322 toward the light guide plate 322. This can minimize the loss of light.

The optical sheet layer 324 is a diffusion sheet 325 for diffusing light incident from the light guide plate 322 in the direction of the liquid crystal display panel 310, and is disposed in front of the diffusion sheet 325 to be disposed by the diffusion sheet 325. And a prism sheet 326 which focuses the diffused light and emits the light in a substantially vertical direction.

An optical pattern layer 326b is formed on the entire surface of the prism sheet 326. In this case, the optical pattern layer 326b is divided into a plurality of zones, and the micro-optical pattern 326a is arranged in one direction in each zone. The micro-optic patterns 326a between neighboring regions are arranged to cross each other at a predetermined angle (an example of being orthogonally arranged in FIG. 8). The optical pattern layer 326b collects light incident from the rear side and emits the light to the front liquid crystal display panel 310.

On the other hand, the protective sheet 327 which can be selectively used is located in front of the prism sheet 326 so that scratches or scratches do not occur due to the prism sheet 326 in contact with the liquid crystal display panel 310.

8 illustrates a liquid crystal display device including a prism sheet according to an embodiment of the present invention, but the present invention is not limited thereto. The liquid crystal display device of the present invention may be a prism sheet according to all the embodiments described above. It may also include.

Furthermore, although the edge type backlight unit is described in the drawings, this is merely an example for convenience of description and the present invention is not limited thereto. Therefore, the present invention can be applied to the backlight unit according to the direct method or the other method, of course.

Accordingly, the above-described drawings and detailed description of the invention are merely exemplary of the present invention, which are used for the purpose of illustrating the present invention, and are used to limit the scope of the invention as defined in the claims or claims. It is not. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Recently, the liquid crystal display (LCD) has been widely used in display devices such as mobile phones, TVs, and various monitors, and this trend is expected to continue in the future. Since the luminance is an important element in the liquid crystal display device, various optical elements used in the liquid crystal display device have been developed to improve the luminance or to improve the durability.

In view of this aspect, the prism sheet used in the liquid crystal display device according to the present invention can minimize damage upon contact with other members due to impact or carelessness of the product while improving light diffusion efficiency. It can contribute to quality improvement. In addition, in the present invention, the vertical and horizontal viewing angles can be enlarged in the liquid crystal display by adjusting the area size and the number of patterns of the micro-optic pattern formed on the prism sheet. For this reason, it is determined that the prism sheet of the present invention can be widely used in a display device in the future.

1 is an exploded perspective view of a general liquid crystal display device.

2 is a structure of a conventional prism sheet.

3 is a structure of a prism sheet according to an embodiment of the present invention.

4 is a perspective view of a prism sheet according to another embodiment of the present invention.

5 is a perspective view of a prism sheet according to another embodiment of the present invention.

6 is a simulation diagram for comparing the brightness of the prism sheet according to the present invention and the conventional general prism sheet.

7 is an exploded perspective view of a liquid crystal display including a prism sheet according to an embodiment of the present invention.

 Explanation of symbols on the main parts of the drawings

110,210,240: base film 120,220,250: fine optical pattern

130, 230, 260: optical pattern layer 310: liquid crystal display panel

320: backlight unit

Claims (20)

A base film having light transmittance; And An optical pattern layer formed on one surface of the base film and having a plurality of micro optical patterns formed thereon for collecting light incident from the rear and emitting the light forward; Including, The optical pattern layer is divided into at least two zones, and the micro-optical pattern in each zone has a predetermined cross section and is continuously arranged in one direction, and at least some of the zones have different sizes, respectively. Prism sheet, characterized in that each micro-optical pattern between the adjacent areas are arranged to cross at a predetermined angle. The method of claim 1, The angle is at least 45 degrees and less than 90 degrees prism sheet. The method of claim 1, Prism sheet, characterized in that the micro-optic pattern between the adjacent areas are arranged to be orthogonal to each other. The method of claim 3, The micro-optic pattern of the at least one zone is characterized in that arranged along the longitudinal direction of the base film. The method of claim 3, The microscopic optical pattern of the at least one zone is characterized in that arranged in the diagonal direction of the base film prism sheet. delete The method of claim 1, At least a portion of each of the zones is characterized in that the number of the micro-optic pattern is different from each other. The method of claim 1, The cross section of each of the micro-optic pattern is a prism sheet, characterized in that having a shape of any one of a polygonal or arc. A light transmitting first base film; A first optical pattern layer formed on the front surface of the first base film and having a plurality of first fine optical patterns formed thereon for collecting the light incident from the rear and emitting the light forward; A light transmissive second base film formed on the entire surface of the first optical pattern layer; And A second optical pattern layer formed on the front surface of the second base film and having a plurality of second fine optical patterns formed thereon for collecting the light passing through the second base film and outputting it forward; Including, The first and second optical pattern layers are each divided into at least two or more zones, and the micro-optical patterns in each of the zones have a predetermined cross section and are continuously arranged in one direction. At least a part of each zone of the layer is different in size, and each micro-optic pattern between adjacent zones of each other is arranged to cross at a predetermined angle, The prism sheet of claim 1, wherein the microscopic optical patterns are arranged to be orthogonal to each other between the respective zones of the first optical pattern layer and the respective zones of the second optical pattern layer corresponding to the respective zones of the first optical pattern layer. 10. The method of claim 9, The angle is at least 45 degrees and less than 90 degrees prism sheet. 10. The method of claim 9, The micro-optic pattern between adjacent regions in the first and second optical pattern layers are arranged to be orthogonal to each other. The method of claim 11, The micro-optic pattern of the at least one zone is characterized in that arranged along the longitudinal direction of the base film. The method of claim 11, The microscopic optical pattern of the at least one zone is characterized in that arranged in the diagonal direction of the base film prism sheet. delete 10. The method of claim 9, At least some of the zones of the first and second optical pattern layers have different numbers of microscopic optical patterns. 10. The method of claim 9, The cross section of each of the micro-optic pattern is a prism sheet, characterized in that having a shape of any one of a polygonal or arc. 10. The method of claim 9, Each zone of the first optical pattern layer and each zone of the second optical pattern layer respectively corresponding to each zone of the first optical pattern layer have the same size. 10. The method of claim 9, The micro optical patterns have the same pattern number and cross-sectional shape between each zone of the first optical pattern layer and each zone of the second optical pattern layer respectively corresponding to each zone of the first optical pattern layer. Prism sheet. A backlight unit comprising the prism sheet according to any one of claims 1 to 5, 7 to 13, and 15 to 18. A liquid crystal display device comprising the backlight unit of claim 19.

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