WO2014014197A1

WO2014014197A1 - Light guide panel, manufacturing method therefor, backlight unit including same, and liquid crystal display including same

Info

Publication number: WO2014014197A1
Application number: PCT/KR2013/004755
Authority: WO
Inventors: 박영우; 카리루카란타루; 최승만; 김현민
Original assignee: 제일모직 주식회사
Priority date: 2012-07-20
Filing date: 2013-05-30
Publication date: 2014-01-23
Also published as: KR20140013218A; TW201409098A

Abstract

The present invention relates to a light guide panel, a manufacturing method therefor, a backlight unit including the same, and a liquid crystal display including the same. More particularly, the present invention relates to a light guide panel, a manufacturing method therefor, a backlight unit including the same, and a liquid crystal display including the same, wherein the light guide panel comprises divided optical patterns on the front side thereof such that shielding properties of the optical patterns can be increased when an optical sheet is stacked while the light guide panel is mounted on a backlight unit, light from a light source can be uniformly emitted to the front side, and pitches or the size or the like of the optical patterns can be changed, thereby easily adjusting an emission angle and exhibiting exterior adjusting performance.

Description

【Specification】

[Name of invention]

Light guide plate, manufacturing method thereof, backlight unit including the same, and liquid crystal display including the same

Technical Field

The present invention relates to a light guide plate, a manufacturing method thereof, a backlight unit including the same, and a liquid crystal display including the same. More specifically, the present invention includes a divided optical pattern, high shielding properties for the optical sheet including a prism sheet, etc. when mounted on the backlight unit, can uniformly emit light from the light source, the height of the optical pattern . The present invention relates to a light guide plate having an easy adjustment of optical characteristics including an emission angle and having an appearance adjustment capability, a manufacturing method thereof, a backlight unit including the same, and a liquid crystal display including the same. Background Art

The backlight unit of the liquid crystal display device includes a light source for supplying light because it cannot emit light by itself. In addition, a light guide plate for emitting light from the light source is included, and an optical sheet such as a prism sheet is stacked on the light guide plate to increase the efficiency of light emitted to the front surface. The light guide plate may be manufactured by injection molding, extrusion, or die casting.

As described in Korean Patent No. 0898740, a master roll having an optical pattern formed thereon is rotatably disposed on a circumferential surface, and the base film is transported spaced apart from the surface of the master roll by a predetermined distance by the transfer roll. After the UV cured material is coated on the transferred base film and passed through the rotating master roll, the optical pattern is transferred to the UV cured material and cured by the ultraviolet irradiation device. Then, the light guide plate having the optical pattern (line pattern form) formed on the master roll is formed. It can manufacture.

Typically the optical pattern is formed in a line pattern on the master by a bite diamond tip. However, such pattern processing requires precision, so that the cross-sectional shape, size, or pitch of the pattern may be uniform, or an optical pattern may be formed over the entire light guide plate. These optical patterns are formed When the light guide plate is mounted on the backlight unit, the shielding property is inferior due to the pattern line, and a contrast line occurs in appearance.

[Detailed Description of the Invention]

[Technical problem]

An object of the present invention is to provide a light guide plate having good shielding properties when the optical pattern is not visible when the optical sheet is stacked when mounted on the backlight unit.

Another object of the present invention is to provide a light guide plate which uniformly emits light emitted from a light source.

Still another object of the present invention is to provide a light guide plate having an easy exit angle adjustment and an appearance adjustment performance.

Still another object of the present invention is to provide a method of manufacturing the light guide plate. Still another object of the present invention is to provide a backlight unit including the light guide plate, and a liquid crystal display device.

Technical Solution

The light guide plate according to the aspect of the present invention includes a side from which light is incident from a light source, a front surface connected to the side to emit light, and a rear surface connected to the side to reflect light, and a plurality of optical patterns dot on the front surface It may be formed in the form.

The optical pattern may be formed in an intaglio.

The separation distance between the optical patterns may be about 200 to about 1000. The separation distance between the optical patterns may decrease with distance from the light source.

The height, width or length of the optical pattern may increase as it moves away from the light source.

The height of the optical pattern may be about 4 to about 80, the width is about 4; about 80 to about 400, and the length may be about 50 to about 300. A line connecting the centers of the optical patterns arranged in one direction with respect to the direction horizontal to the light incident from the light source may form an angle Θ in a predetermined range with the direction in which light is incident from the light source.

The angle Θ may be greater than about 0 ° and less than about 90 °.

The light guide plate may include optical patterns forming different angles Θ. The optical pattern may be a prism, lenticular lens or microlens pattern.

The optical pattern may have a triangular prism or a square pillar shape.

Another method of manufacturing a light guide plate according to the present invention includes the step of extruding a light guide plate with an extrusion furnace formed with an optical pattern forming unit, the optical pattern forming unit each other in a direction perpendicular to the direction perpendicular to the rotational direction of the extrusion roll It may be spaced apart.

The separation distance of the optical pattern forming unit may be about 50 to about 1000.

The separation distance of the optical pattern forming unit may increase from one side of the extrusion to the other side.

The optical pattern forming unit may be a prism, a lenticular lens, or a microlens pattern.

A backlight unit and a liquid crystal display device according to another aspect of the present invention may include the light guide plate. Advantageous Effects

The present invention provides a light guide plate having good shielding properties, uniformly emitting light emitted from a light source, easily adjusting the exit angle, and having an appearance adjustment performance when the optical sheet is not mounted when mounted on the backlight unit. In addition, the present invention provides a method of manufacturing the light guide plate, and a backlight unit and a liquid crystal display device including the same.

[Brief Description of Drawings]

1 illustrates an embodiment of the light guide plate of the present invention. 2 is a cross-sectional view taken along the line A-A 'in FIG.

3 is a cross-sectional view taken along line BB ′ in FIG. 1.

4 is an enlarged cross-sectional view of a prism of the light guide plate of the present invention.

5 is an enlarged view of one cross section of a prism of the light guide plate of the present invention.

Figure 6 shows another embodiment of the light guide plate of the present invention.

Figure 7 shows another embodiment of the light guide plate of the present invention.

Figure 8 shows one embodiment of the extrusion for manufacturing the light guide plate of the present invention. Figure 9 shows another embodiment of the extrusion for manufacturing the light guide plate of the present invention. Figure 10 shows the manufacturing step of the extrusion roll for manufacturing the light guide plate of the present invention. 11 shows a light guide plate of Example 1. FIG.

12 shows the shielding result of Example 1. FIG.

13 illustrates a light guide plate of a comparative example.

14 shows the shielding result of the comparative example. [Best form for implementation of the invention]

The light guide plate according to the aspect of the present invention includes a side from which light is incident from a light source, a front surface connected to the side to emit light, and a rear surface connected to the side to reflect light, wherein the front surface has a plurality of optical patterns It is formed in the form of dots.

Hereinafter, the light guide plate of the present invention will be described with reference to the accompanying drawings.

1 to 7 show the light guide plate of the present invention.

The light guide plate 100, 200, 300 of the present invention has a side surface 10a through which light is incident from a light source, a front surface 20 connected to the side surface to emit light, and a rear surface 30 connected to the side surface and reflecting light. ). The side front and rear surfaces are integrally formed to form a light guide plate. The light guide plate may include another side (not shown) facing the side, and another side 10b connecting the side.

The thickness of the light guide plate is not particularly limited, but may be about 0.5 mm to about 6 mm. The position of the light source may vary depending on the backlight unit on which the light guide plate is mounted. In this specification, it is assumed that the light source is located opposite one side 10a. Of course, a plurality of light sources may also be applied. ^"The back may be a conventional light guide plate lower face. For example, an optical pattern may not be formed on the rear surface, or an optical pattern including a prism, a lenticular lens, a microlens, an embossed pattern, or the like may be formed.

A plurality of optical patterns 40a, 40b ... 40f, 40g are formed on the front surface. The optical pattern emits total light reflected from the side surface.

In the present specification, an 'optical pattern' includes both an embossed and an intaglio form. That is, an embossed optical pattern in which a pattern protrudes out of the light guide plate, and an intaglio optical pattern in which the pattern enters by engraving the inside of the light guide plate. Include all patterns. 1 to 7 illustrate a light guide plate including an optical pattern of an intaglio shape.

On the entire light guide plate, a plurality of optical patterns 40a, 40b ... 40f, 40g are formed in a dot form. In the present specification, 'dot' refers to a form in which the optical pattern is spaced apart from other neighboring optical patterns. For example, the 'dot' may have an island structure surrounded by an unpatterned region in which a pattern is not formed. The non-patterned region may be planar. On the front of the light guide plate, the optical pattern has a range of pitches SI, S2, S3, S, in both the horizontal direction (X direction) and the vertical direction (y direction) in the direction in which light is incident from the light source. Spaced apart by Tl, T2 ₍ T3, ..., T) Through this, as shown in FIGS. 1 to 7, the light guide plate of the present invention is divided optical patterns in which the prism patterns arranged in a conventional line are divided. The line prism is divided into dot prisms in the backlight unit so that the pattern lines are not displayed in appearance.

In the present specification, 'pitch' refers to a distance at which optical patterns are spaced apart from each other based on a direction horizontal to the direction in which light is incident and a direction perpendicular to the direction in which light is incident.

FIG. 2 is a cross-sectional view taken along line AA ′ of the light guide plate of FIG. 1. Optics arranged in one direction with respect to the direction (y direction) perpendicular to the direction in which light is incident from the light source The spacing pitches SI, S2, S3, ... between the patterns 40a, 40e, 40f, 40g may be the same or different. Pitches SI, S2, S3,... May be about 50 μs-about 1000;

3 is a cross-sectional view taken along line B-B 'of the light guide plate of FIG. Pitch (ΤΙ _' Τ2, Τ3, ...), which is the separation distance between the optical patterns 40a, 40b, 40c, 40d arranged in one direction with respect to the direction (X direction) horizontal to the direction in which light is incident from the light source. May be the same or different

Preferably, the pitch decreases away from the light source (gradation form) so that light emitted from the light source is evenly emitted. Pitches Tl, T2, T3,... May be from about 50 to about 1000;

In the separation distance between the optical patterns, the horizontal direction (the X direction) with respect to the distance (SI representing S, S2, S3 ..) spaced from the direction perpendicular to the direction in which light is incident (y direction) The ratio of the distances (T, T2, T3 ..) representing the distance can be adjusted according to the shape of the pattern and the distance.

A spaced plane is formed on the front surface of the light guide plate of the present invention. In this specification

The 'separation plane' refers to a portion of the front surface of the light guide plate formed between the optical patterns and without forming an embossed or engraved optical pattern.

The shape of the separation plane depends on the type of optical pattern, the spacing between the optical patterns, and the like. The separation plane may be rectangular, square, trapezoidal, parallelogram, or irregular round, but is not limited thereto. Since the separation plane is formed between the optical patterns, the shielding property of the optical sheet including a prism may be secured when the light guide plate is stacked on the backlight unit. In addition, the shielding property can be enhanced by adjusting the length and / or width of the separation plane. 1, 6, and 7 illustrate a light guide plate having a rectangular or trapezoidal separation plane.

The area of each of the separation planes arranged in one direction with respect to the direction (y direction) perpendicular to the direction in which light is incident from the light source may be the same or different.

The area of each of the separation planes arranged in one direction with respect to the direction (X direction) horizontal to the direction in which light is incident from the light source may be the same or different. Preferably, as shown in Figure 1, the further away from the light source In order to evenly emit light from the light source, the area of the separation plane decreases away from the light source.

The optical pattern is not particularly limited as long as it is an optical pattern commonly included in the light guide plate field.

For example, although a prism is illustrated as an optical pattern in FIGS. 1 to 7, all of a lenticular lens or a microlens pattern may be included in addition to the prism. The optical pattern may comprise a triangular lamp or square lamp shape.

Hereinafter, the prism will be described with an optical pattern. However, the same may be applied to the lenticular lens or the microlens pattern. The prisms arranged in one direction based on a direction horizontal to the direction in which the light source is incident may have a polygonal shape including a triangle, a rectangle, or the like in cross section. Can be. Degree

1 to 7 show a prism in the form of a triangular lamp having a triangular cross section. The triangle may be an equilateral triangle or an isosceles triangle having the same length of the stool, or an anisotropic triangle having different lengths of the stool.

As shown in FIG. 4, in a prism having a triangular cross section, an angle formed by one surface of the prism 40a and the front surface 20 of the light guide plate is a vertex angle of αβ and ββ and both sides of the prism, respectively.

The emission angle from the light source can be adjusted by adjusting (where α Β + β Β + is 180 ^ο ).

In the prism having a triangular cross section, αβ is an angle formed between one surface 42a of the prism facing the light source and the front surface 20 of the light guide plate, and may be about 40 ° to about 60 °. ββ is an angle formed by one surface 43a of the prism facing the light source and the front surface 20 of the light guide plate, and may be about 40 ° to about 60 °. By making αβ and ββ equal to each other, the prism cross section can be an equilateral triangle or isosceles triangle. The angle at which one side of the prism and the other side except the front of the light guide plate is formed may be 180- (αΒ + βΒ) °.

The prisms arranged in one direction based on a direction perpendicular to the direction in which the light source is incident may have a rectangular, trapezoidal, parallelogram, square, and rectangular deformation shape. Figure 5 shows a prism of rectangular section in length L and height Η. Light efficiency can be made uniform by adjusting the height H, the width W, or the length L of an optical pattern. Based on the direction parallel to the direction in which light is incident, the height, width or length of the optical pattern may increase as it moves away from the light source (gradation form). As a result, light emitted from the light source can be emitted uniformly.

The height of the optical pattern may be about 4 to about 80, the width may be about 4 to about 80, and the length may be about 50 to about 300.

As shown in FIG. 6, a line connecting the centers of the optical patterns 50a, 50b, 50c, 50d, and 50e arranged in one direction with respect to the direction (X direction) horizontal to the direction in which light is incident from the light source ( X) forms an angle Θ in a direction and a range in which light is incident from the light source. The angle may be greater than about 0 ° and less than about 90 °, preferably about 12 ° to about 45 °.

In the case of the optical pattern having a rectangular cross section with respect to the direction horizontal to the light incident direction, the center of the optical pattern may mean a point where the diagonal lines meet in the prism cross section square.

The angle Θ may vary based on a direction (y direction) perpendicular to the direction in which light is incident. That is, the light guide plate may include optical patterns forming different angles (Θ). FIG. 7 illustrates a light guide plate including optical patterns having different angles Θ1 and Θ2. In FIG. 7, the line XI connecting the cores of the optical patterns 60a, 60b, 60c, 60d, and 60e arranged in one direction with respect to the direction (X direction) horizontal to the direction in which light is incident from the light source. The angle (Θ1) formed by the direction in which light is incident from the light source is different from the line (X2) connecting the centers of the optical patterns 60a, 60f, and 60g and the angle (Θ2) formed by the direction in which light is incident from the light source. Can be. According to another aspect of the present invention, a method of manufacturing a light guide plate is to manufacture a light guide plate by extrusion, and thus, a light guide plate having a different optical pattern having different widths, heights, or lengths of optical patterns may be manufactured.

The light guide plate manufacturing method includes the step of extruding the original light guide plate by extrusion. 8 and 9 show an extrusion roll for manufacturing a light guide plate used in the production method of the present invention. On the surface of the light guide plate extrusion rolls 400 and 500, Optical pattern forming portions 80a and 80b are formed that can form an optical pattern of a specific shape through contact and extrusion steps. In addition, the light guide plate extrusion roll may include an axis 110 for supporting and rotating the light guide plate.

8 and 9 illustrate an embossed optically formed portion, but may include an intaglio-shaped optical pattern forming portion.

In the light guide plate extrusion, the optical pattern forming portion is formed in a dot shape. That is, the optical pattern forming portions are spaced apart by a predetermined range of separation distances S and T based on the direction horizontal to the roll rotation direction and the direction perpendicular to the rotation direction.

The above description of the above-described optical pattern may be applied to all of the optical pattern forming units.

That is, as described above with respect to the optical pattern, the separation distances (SI, S2, S3, ...) of the optical pattern forming portion may be the same or different with respect to the direction (y direction) horizontal to the rotational direction of the roll. The separation distances SI, S2, S3, ... can be from about 50 um to about 1000.

The separation distances (Tl, T2, T3, ...) between the optical pattern forming parts arranged in one direction with respect to the direction (X direction) perpendicular to the rotation direction of may be the same or different. Separation distance Tl, T2, T3,... May be about 50 to about 1000 ms.

The separation distance of the optical pattern forming unit may increase from one side of the extrusion roll toward the other side.

10 illustrates a manufacturing process of the light guide plate extrusion roll.

A light guide plate extrusion roll 600 is prepared that includes a conventional optical pattern 90 in which no split pattern is formed. Then, the roll is stopped at a constant speed. The optical patterns 80a 'and 80b' are formed by chamfering and removing part of the pattern by horizontally moving the bit 120 on the roll at the point and direction in which the division pattern is to be formed. By repeating the pattern removal process by the bite, the light guide plate extrusion roll 400 having the optical patterns 80a and 80b divided as shown in FIG. 8 can be manufactured.

In addition, a light guide plate extrusion including a normal optical pattern in which a split pattern is not formed is manufactured. Then, turn to stop at a constant speed. Horizontally roll the bite at the point and direction in which you want to form the split pattern. By moving and rotating at a constant speed at the same time, the light guide plate extrusion 500 in which the portion from which the pattern is removed becomes a helical curve can be manufactured.

The optical pattern including the prism to be applied to the light guide plate should be an anisotropic triangle, not an isosceles triangle, in order to adjust the exit angle, and the prism should also have a gradation pattern with variable pitch, height, or width. In the conventional light guide plate manufacturing master roll, the optical pattern formation part has the same pitch, and the prism shape had the cross-section triangular structure, and it was difficult to adjust the exit angle. On the other hand, the light guide plate extrusion of the present invention makes it possible to manufacture a light guide plate that can control the optical properties by adjusting the direction of the bite, the pitch of the bite.

The light guide plate may be manufactured by extruding the light guide plate original plate using the light guide plate extrusion roll described above.

The light guide plate disc is not particularly limited as long as it is an optically transparent resin commonly used in manufacturing the light guide plate. The optically transparent resin may be a (meth) acrylic resin, a polycarbonate resin, a styrene resin, an olefin resin, or a polyester resin. Preferably it may be made of a polymethyl methacrylic resin.

The extrusion conditions are not particularly limited, but in the case of acrylic the extrusion temperature can be about 8C C to about licrc. In another aspect of the present invention, the backlight unit and the liquid crystal display may include the light guide plate. The backlight unit may be included in the optical display device in a conventional manner.

[Form for implementation of invention]

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, this is presented as a preferred example of the present invention and in no sense is it to be construed as limiting the present invention.

The information that is not described here will be omitted in the technical field can be inferred by those skilled in the art. Example 1

An extrusion for manufacturing a light guide plate in which a divided optical pattern forming portion is not formed is produced. The cross section of an optical pattern formation part is a triangle with respect to the direction horizontal to a roll rotation direction. Rotate and stop the roll and remove part of the pattern by moving the bite horizontally on. At this time, the pitch of the optical pattern forming unit

400 j «m ~ 800 Ά, 6 ^ m ~ 12 폭 in width, 4 ^ m ~ 10 in height. The extrusion roll for light guide plate manufacture of FIG. 8 with which the optical pattern formation part was formed is manufactured. The light guide plate of polymethyl methacrylate material is transferred and the light guide plate extrusion roll is extruded to manufacture the light guide plate. Example 2

According to the method of Example 1 to produce a light guide plate by extruding the light guide plate extrusion, a light guide plate having a angle θ of 25 ° in FIG. Comparative example

Light guide plate in which the divided optical pattern forming part is not formed in the above embodiment. The light guide plate is extruded using the extrusion for producing the line prism split pattern of the present invention, and the light guide plate is extruded using the existing line prism extrusion roll. Shielding properties were evaluated for the light guide plates prepared in Examples and Comparative Examples.

The shielding property indicates whether the pattern of the bottom surface of the light guide plate can be seen when the MLA film is laminated on the light guide plate of the backlight unit. Put the prism sheet (MLA film) on the light guide plate with the 32-inch LCD module using the edge LED light source on, and then observe whether the pattern is visible when the light guide plate is placed. The results are shown in Table 1 and FIGS. 11 to 14.

FIG. 11 illustrates a light guide plate on which a bottom pattern of a line prism division type of Example 1 is formed, and FIG. 12 illustrates shielding results. As shown in FIG. 12, the light guide plate of the present invention was shielded with one sheet of MLA film because the lower surface pattern of the line prism division type was not recognized. FIG. 13 illustrates a light guide plate on which a conventional line prism of the comparative example is formed, and FIG. 14 illustrates shielding results. As shown in Figure 14, the light guide plate of the comparative example was compared to the light guide plate of the present invention, the line prism is relatively visible, it is impossible to shield with the MLA film, an additional sheet was required.

Table 1

o: line prisms do not recognize the pattern

X ： Pattern is recognized when line prism

Claims

[Range of request]

[Claim 1]

A side from which light is incident from a light source, a front surface connected to the side to emit light, and a rear surface connected to the side to reflect light,

A light guide plate in which a plurality of optical patterns are formed in a dot shape on the front surface.

[Claim 2]

The light guide plate according to claim 1, wherein the optical pattern is formed in an intaglio.

[Claim 3]

The light guide plate of claim 1 wherein the separation distance between the optical patterns is about 50 to about 1000;

[Claim 4]

The light guide plate according to claim 1, wherein the separation distance between the optical patterns decreases away from the light source.

[Claim 5]

The light guide plate of claim 1, wherein a height, a width, or a length of the optical pattern increases with distance from the light source.

[Claim 6]

The light guide plate of claim 1 wherein the optical pattern has a height of about 4 m to about 80 iM, a width of about 4 to about 80 / mi, and a length of about 50 to about 300;

[Claim 7]

The line connecting the centers of the optical patterns arranged in one direction based on a direction horizontal to the direction in which light is incident from the light source. A light guide plate which forms an angle (Θ) in a direction and a direction in which light is incident from a light source.

[Claim 8]

The light guide plate of claim 7 wherein the angle Θ is greater than about 0 ° and less than about 90 ^ο .

[Claim 9]

8. The light guide plate of claim 7, wherein the light guide plate includes an optical pattern for forming different angles (Θ).

[Claim 10]

The light guide plate of claim 1, wherein the optical pattern is a prism, a lenticular lens, or a microlens.

[Claim Clause 11]

The light guide plate of claim 1, wherein the optical pattern has a triangular lamp or a square pillar shape.

[Claim 12]

And extruding the light guide plate disc with an extrusion roll having a plurality of optical pattern forming parts, wherein the optical pattern forming parts are formed in a dot shape.

[Claim 13]

The method of claim 12, wherein the distance between the optical pattern forming portions is about 50; mi to about 1000.

[Claim 14] The method of claim 12, wherein the separation distance of the optical pattern forming unit increases from one side to the other side of the extrusion.

[Claim 15]

The method of claim 12, wherein the optical pattern forming unit is a prism, a lenticular lens, or a microlens.

[Claim 16]

A backlight unit comprising the light guide plate of claim 1.