KR101376854B1 - Optical sheet, method for manufacturing the optical sheet, backlight unit comprising the optical sheet and liquid crystal display comprising the optical sheet - Google Patents

Abstract

Disclosed are an optical sheet, a method of manufacturing the same, a backlight unit having the same, and a liquid crystal display including the same. The optical sheet is formed between a substrate that transmits light incident from the outside, a prism pattern formed on the substrate, and focuses some light from the incident light from the outside, and is formed between the prism patterns and reflects some light from the light incident from the outside. It includes a light reflection pattern.

Backlight unit, optical sheet, prism pattern, light reflection pattern, luminance

Description

Optical sheet, its manufacturing method, a backlight unit having the same, and a liquid crystal display having the same

1 is a perspective view illustrating an optical sheet according to an embodiment of the present invention.

2 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 1.

3A to 3C are cross-sectional views of processes for schematically describing a method of manufacturing an optical sheet according to an embodiment of the present invention.

4 is an exploded perspective view illustrating the configuration of a backlight unit according to an exemplary embodiment of the present invention.

5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

6 is an exploded perspective view for explaining the configuration of a backlight unit according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along the line VII-VII 'of FIG. 6.

8 is an exploded perspective view illustrating a configuration of a liquid crystal display according to an exemplary embodiment of the present invention.

9 is a cross-sectional view taken along the line VII-VII 'of FIG. 8.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS FIG.

130: optical sheet 132: base material

134: prism pattern 136: light reflection pattern

210, 310: backlight unit 220, 320: light source

400: liquid crystal display 410: liquid crystal panel

The present invention relates to an optical sheet, a manufacturing method thereof, a backlight unit having the same, and a liquid crystal display including the same.

A liquid crystal display classified into a light receiving display device includes a backlight unit mounted below a liquid crystal panel displaying an image.

The conventional backlight unit may include not only a light source for emitting light but also an optical sheet for improving optical characteristics of the backlight unit, for example, brightness. For example, the backlight unit may include a substrate and an optical sheet having a prism pattern formed on one surface of the substrate.

Since the prism pattern of the optical sheet is generally formed in a triangular prism bar shape, the prism pattern has first and second mirror surfaces having vertices on a cross section.

However, light incident from the light emitted from the light source similarly to the inclination of each of the first and second mirror surfaces of the prism pattern may be emitted at an oblique angle even though it passes through the prism pattern. That is, the incident light similar to the inclination of each of the first and second mirror surfaces may serve as lost light which does not help the front brightness. This may eventually lower the luminance of the liquid crystal display.

Accordingly, an object of the present invention is to provide an optical sheet capable of improving luminance, a method of manufacturing the same, a backlight unit having the same, and a liquid crystal display having the same.

Further technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following description. It can be understood.

Optical sheet according to an embodiment of the present invention for achieving the above technical problem is a substrate for transmitting the light incident from the outside; A prism pattern formed on the substrate and condensing some light from the light incident from the outside; And a light reflection pattern formed between the prism patterns and reflecting some light from the light incident from the outside.

On the other hand, the manufacturing method of an optical sheet according to an embodiment of the present invention for achieving the above technical problem comprises the steps of preparing a substrate; Forming a prism pattern spaced apart from each other on the substrate; Forming a light reflection pattern between the prism patterns.

On the other hand, the backlight unit according to an embodiment of the present invention for achieving the above technical problem is a light source for emitting light; And a prism pattern formed to transmit light incident from the light source, a prism pattern formed on the substrate to focus some light from the light incident from the light source, and a portion of light formed between the prism patterns and incident from the light source. It includes an optical sheet having a light reflection pattern for reflecting.

According to another aspect of the present invention, there is provided a liquid crystal display comprising: a light source for emitting light; A portion of a substrate that transmits light incident from the light source, a prism pattern formed on the substrate to focus some light from the light incident from the light source, and a portion of light formed between the prism pattern and incident from the light source; An optical sheet having a light reflection pattern to reflect; And a liquid crystal panel which displays an image using light emitted from the light source.

The details of other embodiments are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings.

Like reference numerals refer to like elements throughout the specification. In addition, when describing the arrangement relationship between the components throughout the specification, when it is disposed on the top, this includes not only the case in which it is arranged in the upper direction in the vertical direction, but also the case in which it is arranged in the oblique direction. Likewise, when describing the arrangement relationship among the respective components throughout the specification, the term "disposed at the bottom" includes not only the case of being disposed at the lower side in the vertical direction but also the case of being disposed at the lower side in the oblique direction.

Hereinafter, an optical sheet, a method of manufacturing the same, a backlight unit having the same, and a liquid crystal display including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view illustrating an optical sheet according to an embodiment of the present invention. 2 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 1.

1 and 2, an optical sheet 130 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display. In this case, the optical sheet 130 may improve the optical characteristics of the backlight unit, for example, brightness.

The optical sheet 130 may include a substrate 132, a prism pattern 134, and a light reflection pattern 136.

The substrate 132 may transmit light L1, L2, L3, and L4 incident from the external light source 220. The substrate 132 may be formed of a light transmissive material, for example, any one material selected from the group consisting of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy.

The prism pattern 134 may be formed on one surface of the substrate 132, for example. Specifically, the prism pattern 134 may include, for example, first and second side surfaces 134a and 134b disposed below the prism pattern 134, and first and second mirror surfaces positioned above the prism pattern 134. 134c and 134d can be provided.

Each of the first and second side surfaces 134a and 134b of the prism pattern 134 is formed to be in contact with the top surface of the substrate 132, and may be formed to be perpendicular to the top surface of the substrate 132, for example. Can be. Accordingly, the lower portion of the prism pattern 134 may be formed in a substantially rectangular bar shape.

Each of the first and second mirror surfaces 134c and 134d of the prism pattern 134 is formed to extend from each of the first and second side surfaces 134a and 134b and may be formed to have a vertex P1 on a cross section. Can be. That is, the top ends of each of the first and second mirror surfaces 134c and 134d may be formed to meet each other. Accordingly, the upper portion of the prism pattern 134 may be formed in a substantially triangular bar shape.

The prism pattern 134 may collect some light L1 from among the lights L1, L2, L3, and L4 incident from the external light source 220. For example, when the light L1 having a predetermined slope passes through the substrate 132 and proceeds toward the second mirror surface 134d, the light L1 is refracted and collected by the second mirror surface 134d. Can be discharged upwards.

In addition, the prism pattern 134 totally reflects some light L2 from among the lights L1, L2, L3, and L4 incident from the external light source 220, thereby allowing the light L2 to be recycled. For example, the light L2 having a vertical inclination and transmitted through the substrate 132 is totally reflected at the first and second mirror surfaces 134c and 134d to be transmitted through the substrate 132 again. In this case, when the reflecting plate is disposed under the optical sheet 130, the light L2 may be recycled.

The prism patterns 134 may be formed to be spaced apart from each other to expose a portion of one surface of the substrate 132.

The light reflection pattern 136 may be formed between the prism patterns 134, specifically, on one surface of the substrate 132 exposed by the prism pattern 134 to be in contact with the prism pattern 134. For example, the light reflection pattern 136 may be formed to be in contact with the first and second side surfaces 134c and 134b of the prism pattern 134, so that the light reflection pattern 136 may have a rectangular or U-shaped shape in cross section. It is not limited.

The light reflection pattern 136 may reflect some light L3 among the lights L1, L2, L3, and L4 incident from the outside. In this case, when the reflecting plate is disposed under the optical sheet 130, the light L3 may be recycled.

The light reflection pattern 136, in particular, prevents incident light L4 from passing through the prism pattern 134, similar to the inclination of each of the first and second mirror surfaces 134c and 134d, thereby suppressing generation of lost light. can do.

This will be described in more detail as follows. If the light reflection pattern 136 is not present, some of the light L4, that is, the slope of the light L1, L2, L3, and L4 incident from the outside is similar to the slope of the first mirror surface 134c and the first The light L4 incident in the mirror surface 134c direction is sequentially obliquely emitted upward through the first and second mirror surfaces 134c and 134d to act as lost light. However, since the light L4 is substantially reflected by the light reflection pattern 136, the light L4 may be recycled.

This is a point P2 at which one of the first and second side surfaces 134a and 134b, for example, the first side surface 134a and the upper surface of the substrate 132 is in contact with each other (ie, a light reflection pattern). Of the lower right side of the substrate and the upper surface of the substrate) and the line segment S1 connecting the vertices P1 of the first and second mirror surfaces 134c and 134d with the upper surface of the substrate 132. In one of the first and second mirror surfaces 134c and 134d, for example, an angle θ2 between the extension line S2 of the first mirror surface 134c and the upper surface of the substrate 132 is large. Do.

That is, when θ1 is greater than θ2, the light L4 that is incident similarly to the slope of the first mirror surface 134c may not be reflected to the first mirror surface 134c and may be reflected by the light reflection pattern 136. . In addition, the light L1 incident to the slope of the first mirror surface 134c and passing between the light reflection patterns 136 travels in the direction of the second mirror surface 134d, and the second mirror surface 134d. ) Can be refracted and focused and emitted upward.

For this reason, the front luminance of each of the backlight unit and the liquid crystal display including the optical sheet 130 may increase significantly.

3A to 3C are cross-sectional views of processes for schematically describing a method of manufacturing an optical sheet according to an embodiment of the present invention.

In order to manufacture the optical sheet 130 according to an embodiment of the present invention, first, as shown in FIG. 3A, prismatic patterns 134 spaced apart from each other are formed on the substrate 132.

Specifically, first, a substrate 132 having a light transmissive material is prepared. Subsequently, the substrate 132 is introduced in a roll to roll manner into a manufacturing equipment provided with a master roll on which a reverse phase pattern corresponding to the prism pattern 134 is formed, and then a photocurable polymer on the master roll. After filling the resin solution, the photocurable polymer resin solution filled in the master roll is transferred onto the substrate 132. Subsequently, the prism pattern 134 may be formed by curing the photocurable polymer resin solution. However, the formation of the prism pattern 134 may vary depending on the manufacturing equipment thereof, and is not limited to the above.

Next, as illustrated in FIGS. 3B and 3C, the light reflection pattern 136 is formed between the prism patterns 134.

Specifically, first, as shown in FIG. 3B, the light reflection crude liquid 136a is applied between the prism patterns 134. In this case, the light reflection roughening liquid 136a may be partially present on the first and second mirror surfaces 134c and 134d of the prism pattern 134, but after a predetermined time, the first and second mirror surfaces 134c, Since it flows down the base material 132 by 134d), the light reflection crude liquid 136a does not remain on the said 1st and 2nd mirror surface 134c and 134d eventually. Here, the light reflection crude liquid 136a may include, for example, a photocuring agent, a reflective material, and a solvent.

Subsequently, as shown in FIG. 3C, the light reflection crude liquid is cured by irradiating the substrate 132 with, for example, ultraviolet (UV) light. As a result, the light reflection pattern 136 may be formed on the substrate 132.

As described above, when the prism pattern 134 is formed on the substrate 132 and then the light reflection pattern 136 is formed, the prism pattern 134 and the light reflection pattern 136 are separately aligned. The advantage is that you do not have to.

On the other hand, Figure 4 is an exploded perspective view for explaining the configuration of the backlight unit according to an embodiment of the present invention. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4. In FIG. 4, an edge type backlight unit is illustrated as the backlight unit, but the present invention is not limited thereto. In addition, since the optical sheet shown in FIG. 4 is the same as the optical sheet shown in FIG. 1, overlapping description is abbreviate | omitted and only the characteristic is demonstrated.

4 and 5, the backlight unit 210 according to an embodiment of the present invention may be provided in the liquid crystal display. In this case, the backlight unit 210 may provide light to the liquid crystal panel of the liquid crystal display device.

The backlight unit 210 may include a light source 220 and an optical sheet 130. The backlight unit 210 may further include a light guide plate 240, a reflection plate 250, a bottom cover 260, and a mold frame 270.

The light source 220 can generate light using driving power applied from the outside, and can emit the generated light.

The light source 220 may be formed on at least one side of the light guide plate 240 along the X axis direction that is the long axis direction of the light guide plate 240 or may be formed on both sides of the light guide plate 240 along the X axis direction At least one or more of them may be formed. Here, the light emitted from the light source 220 is incident directly into the light guide plate 240, or a light source housing formed to surround a portion of the light source 220, for example, about 3/4 of the outer peripheral surface of the light source 220 ( The light may be incident on the light guide plate 240 after being reflected by the light source 222.

Specifically, the light source 220 may include a Cold Cathode Fluorescent Lamp (CCFL), a Hot Cathode Fluorescent Lamp (HCFL), an External Electrode Fluorescent Lamp (EEFL), and a Light Emitting Diode. It may be one of (Light Emitting Diode: LED), but is not limited thereto.

The optical sheet 130 may be disposed on the light guide plate 240, and may include a substrate 132, a prism pattern 134, and a light reflection pattern 136 as shown in FIG. 1.

The optical sheet 130 may improve optical characteristics, for example, brightness of the backlight unit 210 by collecting some light from the light emitted from the light source 220. In addition, since the optical sheet 130 may reflect some light from the light emitted from the light source 220 in the direction of the reflector 250, the front luminance of the backlight unit 210 may be further improved. Here, the optical sheet 130 may be stacked in two layers of the optical sheet 130 illustrated in FIG. 1, and the prism patterns 134 of the optical sheet 130 may cross each other.

According to the specification of the backlight unit 210, at least one or more of an optical sheet, for example, a protective sheet, a diffusion sheet, and a reflective polarizing film, which are not shown in addition to the optical sheet 130, may be additionally provided.

The light guide plate 240 may be disposed to face the light source 220, and may guide the light so that light incident from the light source 220 is emitted upward.

The reflector 250 is disposed below the light guide plate 240, and may reflect light emitted downward from the light source 220 through the light guide plate 240 upward. In addition, the reflector 250 is reflected from the light reflection pattern 136 of the optical sheet 130 among the light emitted from the light source 220 and then reflected back downward through the light guide plate 240. Can be.

The bottom cover 260 may include a bottom part 262 and a side part 264 formed to extend from the bottom part 262 to form an accommodation space. The light source 220 and the optical sheet 130 may be formed in the accommodation space. I can store it. In addition, the bottom cover 260 may accommodate the reflective plate 250 and the light guide plate 240 in the storage space.

The mold frame 270 may be formed in a substantially rectangular frame shape and disposed at the outermost portion of the backlight unit 210 to surround the edge of the optical sheet 130. The mold frame 270 may be fastened to the bottom cover 260 in a top down manner from an upper side of the bottom cover 260.

6 is an exploded perspective view for describing a configuration of a backlight unit according to an embodiment of the present invention. FIG. 7 is a cross-sectional view taken along the line VII-VII 'of FIG. 6. In FIG. 6, the direct type backlight unit is illustrated as the backlight unit, but the present invention is not limited thereto. On the other hand, the backlight unit shown in FIG. 6 is substantially the same as the backlight unit shown in FIG. 4 except for the arrangement of the light source, and thus description thereof will not be repeated, and only its features will be described.

6 and 7, the backlight unit 310 according to an exemplary embodiment of the present invention may be provided in the liquid crystal display. In this case, the backlight unit 310 may provide light to the liquid crystal panel of the liquid crystal display device.

The backlight unit 310 may include a light source 320 and an optical sheet 130. The backlight unit 310 may further include a reflection plate 350, a bottom cover 360, a mold frame 370, and a diffusion plate 380.

At least one light source 320 may be disposed below the diffusion plate 380. Therefore, the light emitted from the light source 320 can be directly incident on the diffuser plate 380.

The optical sheet 130 may be disposed on the diffuser plate 380, and may include a substrate 132, a prism pattern 134, and a light reflection pattern 136 as shown in FIG. 1.

The optical sheet 130 may improve optical characteristics of the backlight unit 310, for example, brightness by condensing some light from the light emitted from the light source 320. In addition, since the optical sheet 130 may reflect some light from the light emitted from the light source 320 in the direction of the reflecting plate 350, the front brightness of the backlight unit 310 may be further improved. Here, the optical sheet 130 may be stacked in two layers of the optical sheet 130 illustrated in FIG. 1, and the prism patterns 134 of the optical sheet 130 may cross each other.

The diffusion plate 380 may be disposed between the light source 320 and the optical sheet 130, and may diffuse light incident from the light source 320 upward. This is to prevent the shape of the light source 320 from being visible through the backlight unit 310 and to further diffuse the light.

8 is an exploded perspective view for describing a configuration of a liquid crystal display according to an exemplary embodiment of the present invention. 9 is a cross-sectional view taken along the line VII-VII 'of FIG. 8. 8 illustrates the backlight unit illustrated in FIG. 4 as the backlight unit, the present invention is not limited thereto, and the backlight unit illustrated in FIG. 6 may be employed as the backlight unit. Meanwhile, since the backlight unit illustrated in FIG. 8 is the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

8 and 9, the liquid crystal display 400 according to an exemplary embodiment may display an image by using the electro-optical characteristics of the liquid crystal.

The liquid crystal display device 400 may include a backlight unit 210 and a liquid crystal panel 410.

The backlight unit 210 may be mounted under the liquid crystal panel 410 and may provide light to the liquid crystal panel 410.

The backlight unit 210 may include a light source 220 and an optical sheet 130. The backlight unit 210 may further include a light guide plate 240, a reflection plate 250, a bottom cover 260, and a mold frame 270. Here, as described above, some of the light incident from the light source 220 may be recycled by the light reflection pattern 136 of the optical sheet 130, so that the front luminance of the liquid crystal display device 400 is increased. Can rise.

The liquid crystal panel 410 is seated on the mold frame 270 and may be fixed by the top cover 420 fastened to the bottom cover 260 in a top down manner.

The liquid crystal panel 410 can display an image using light provided from the backlight unit 210, specifically, light emitted from the light source 220.

The liquid crystal panel 410 may include a color filter substrate 412 and a thin film transistor substrate 414 facing each other with a liquid crystal therebetween.

The color filter substrate 412 can realize the color of the image to be displayed through the liquid crystal panel 410.

The color filter substrate 412 may include a color filter array formed as a thin film on a transparent substrate such as glass or plastic, for example, an red / green / blue color filter. Here, the upper polarizer may be disposed on the color filter substrate 412.

The thin film transistor substrate 414 is electrically connected to a printed circuit board 418 on which a plurality of circuit components are mounted through a driving film 416. [ The thin film transistor substrate 414 may apply a driving voltage provided from the printed circuit board 418 to the liquid crystal in response to a driving signal provided from the printed circuit board 418.

The thin film transistor substrate 414 may include a thin film transistor and a pixel electrode formed as a thin film on another substrate of a transparent material such as glass or plastic. Here, a lower polarizer may be attached to a lower portion of the thin film transistor substrate 414.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. You will be able to understand that.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

According to the present invention, since the light incident on the optical sheet can be collected or reflected and recycled, the front luminance of each of the backlight unit and the liquid crystal display including the optical sheet can be increased.

Claims (15)

A substrate that transmits light incident from the outside; A plurality of prism patterns formed on the substrate and condensing some light from the light incident from the outside; And Is formed between the prism pattern, including a plurality of light reflection patterns reflecting some light from the light incident from the outside, The prism patterns are formed to be spaced apart from each other, The prism pattern and the light reflection pattern are formed to contact, The light reflection pattern is an optical sheet, characterized in that formed in a U-shape on the cross section. delete delete delete delete delete Preparing a substrate; Forming a prism pattern spaced apart from each other on the substrate; Forming a light reflection pattern between the prism patterns; Forming the light reflection pattern, Applying a light reflection crude liquid between the prism patterns; Hardening the said light reflection crude liquid manufacturing method of the sheet. delete A light source for emitting light; And A base material that transmits light incident from the light source, a plurality of prismatic patterns formed on the base material and focusing some light from the light incident from the light source, and a portion of the light formed between the prism patterns and incident from the light source Including an optical sheet having a plurality of light reflection patterns reflecting light, The prism patterns of the optical sheet are formed to be spaced apart from each other, The prism pattern and the light reflection pattern of the optical sheet are formed to be in contact, The light reflection pattern is a backlight unit, characterized in that formed in a U-shape on the cross section. delete delete delete delete delete A light source for emitting light; A base material that transmits light incident from the light source, a plurality of prismatic patterns formed on the base material and focusing some light from the light incident from the light source, and a portion of the light formed between the prism patterns and incident from the light source An optical sheet having a plurality of light reflection patterns reflecting light; And It includes a liquid crystal panel for displaying an image using the light emitted from the light source, The prism patterns are formed to be spaced apart from each other, The prism pattern and the light reflection pattern are formed to contact, The light reflection pattern is a liquid crystal display, characterized in that formed in a U-shape on the cross section.

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