KR20150003055A - BackLight Unit and Liquid Crystal Display device Comprising The Same - Google Patents

BackLight Unit and Liquid Crystal Display device Comprising The Same Download PDF

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Publication number
KR20150003055A
KR20150003055A KR1020130076038A KR20130076038A KR20150003055A KR 20150003055 A KR20150003055 A KR 20150003055A KR 1020130076038 A KR1020130076038 A KR 1020130076038A KR 20130076038 A KR20130076038 A KR 20130076038A KR 20150003055 A KR20150003055 A KR 20150003055A
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KR
South Korea
Prior art keywords
light
guide plate
light guide
lower pattern
pattern
Prior art date
Application number
KR1020130076038A
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Korean (ko)
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KR102053438B1 (en
Inventor
이동석
방주영
김희철
손영은
최민규
Original Assignee
엘지디스플레이 주식회사
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Priority to KR1020130076038A priority Critical patent/KR102053438B1/en
Publication of KR20150003055A publication Critical patent/KR20150003055A/en
Application granted granted Critical
Publication of KR102053438B1 publication Critical patent/KR102053438B1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

Abstract

A backlight unit according to one embodiment of the present invention includes: a light source which supplies light, an incident part which guides light inputted from the light source and includes a first bottom pattern; a reflection part which includes a second bottom pattern; and a light guide plate which is located between the incident part and the reflection part and includes a mixing unit which includes the first and second bottom patterns.

Description

BACKLIT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE COMPRESSING THE SAME Technical Field [1] The present invention relates to a backlight unit,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit and a liquid crystal display, and more particularly, to a backlight unit capable of controlling outgoing light by a light guide plate and improving a light collecting effect and improving a hot spot and a bright line in a light- To a liquid crystal display device.

BACKGROUND ART [0002] Liquid crystal display devices (LCDs) are widely used because of advantages such as low power driving, thin structure, and excellent image quality. In such a liquid crystal display device, a liquid crystal panel comprising two substrates facing each other and liquid crystal interposed therebetween is used. The liquid crystal panel displays an image by changing the arrangement of the liquid crystal by the electric field generated between the liquid crystal panels.

Such a liquid crystal panel requires a light supply device such as a backlight unit (BLU) in order to display an image as a non-light emitting type display panel. In general, a liquid crystal display device includes a liquid crystal panel and a backlight unit ). Such a backlight unit is divided into an edge type BLU and a bottom type BLU according to the position of a light source. Further, the backlight unit (BLU) includes a light guide plate and various kinds of optical sheets so as to efficiently transmit and use the light supplied to the light source to the liquid crystal panel.

In recent years, due to the tendency of the thickness of the liquid crystal display device to be thinner, the optical sheet and the light guide plate have been made as thin as possible, and the effect has been improved to be equal to or higher than that of the conventional products. Therefore, an edge type backlight unit is often used in comparison with a direct-type backlight unit, and a pattern is formed on the upper and lower surfaces of the light guide plate to compensate the reduced optical sheet.

In the conventional backlight unit, a light guide plate and a reverse prism sheet, to which a pattern is applied at the bottom, are disposed on the light guide plate to achieve a light converging effect. However, in this structure, there is a problem that hot spots and bright lines are generated at the light-incident portion of the light guide plate where the light source is located.

The present invention provides a backlight unit capable of controlling outgoing light by a light guide plate, improving a light collecting effect, and improving a hot spot and a bright line of a light incident portion of a light guide plate, a method of manufacturing the same, and a liquid crystal display device including the same.

In order to achieve the above object, a backlight unit according to an embodiment of the present invention includes a light source for providing light, and a light guide for guiding light incident from the light source, the light incident portion including a first lower pattern, And a light guide plate disposed between the light-incident portion and the reflection portion and including the first and second lower patterns.

And the light-incident portion is an area from an incident surface of the light guide plate through which light is incident from the light source to 10% of the length of the light guide plate.

And the first lower pattern is hemispherical.

And the reflective portion is a region other than a region of up to 30% of the length of the light guide plate from the incident surface.

And the second lower pattern is formed of a negative or an embossed pattern.

And the second lower pattern is formed into a prism shape by an inclined surface and a sub-surface.

And an inclined angle formed by the inclined surface and the lower surface of the light guide plate is smaller than a subangular inclined angle formed by the lower surface and the sub-inclined surface.

And the inclined surface is positioned closer to the incident surface of the light guide plate than the sub-inclined surface.

And the mixing unit is characterized in that the first lower pattern and the second lower pattern are regularly or irregularly arranged.

According to another aspect of the present invention, there is provided a liquid crystal display comprising a light source for providing light, a light guide for guiding light incident from the light source, a light incident portion including a first lower pattern, A light guide plate disposed between the light-incident portion and the reflection portion and including a mixing portion including the first and second lower patterns, an optical sheet positioned on the light guide plate, and an optical sheet positioned on the optical sheet, And a liquid crystal panel.

According to another aspect of the present invention, there is provided a method of manufacturing a backlight unit, comprising: preparing a base of a light guide plate having a light entrance portion, a mixing portion, and a reflection portion; forming a second lower pattern on the mixing portion and the reflection portion, And forming a first lower pattern on the bottom surface of the base in the light-entering portion and the mixing portion.

The forming of the first lower pattern is characterized in that the lower surface of the base is directly irradiated with a laser to form the first lower pattern.

The forming of the second lower pattern may include a lower cutting step of cutting a lower surface of the base to form an inclined surface and a sub-inclined surface, and a step of forming a flat surface by re- The method comprising the steps of:

The backlight unit according to the present invention includes a plurality of first lower patterns and a second lower pattern formed on a light guide plate having a light entering portion, a mixing portion, and a reflecting portion, thereby preventing hot spots occurring in a region adjacent to the light source, There is an advantage that it can be prevented.

1 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention;
2 is a perspective view showing a front surface of a light guide plate according to an embodiment of the present invention.
3 is a perspective view showing the back surface of the light guide plate of Fig. 2;
4 is a cross-sectional view showing a cross section of the light guide plate of Fig. 2;
5 is a view showing a first lower pattern of the light guide plate.
6 is a photograph showing the first lower pattern of the light guide plate.
7 and 8 are a perspective view and a sectional view showing second lower patterns of the light guide plate;
9 is a photograph showing the second lower pattern of the light guide plate.
10 is a photograph showing a first lower pattern and a second lower pattern formed on the light guide plate;
11 is a sectional view for explaining a light path by a lower pattern in the light guide plate.
12 is a flowchart showing a manufacturing method of a light guide plate according to the present invention.
13 is a view showing a method of forming an upper pattern on a light guide plate.
14 is a photograph showing the second lower pattern.
15 to 17 show a method of manufacturing a second lower pattern on a light guide plate.
18 is a view showing a method of manufacturing a first lower pattern on a light guide plate.
19 is a photograph showing the first lower pattern.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, well-known functions or constructions are not described in detail to avoid unnecessarily obscuring the subject matter of the present invention.

1 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.

1, a liquid crystal display 100 according to an exemplary embodiment of the present invention includes a liquid crystal panel 110, a backlight unit 130, a support main 140, a bottom cover 150, a top cover 160, .

The liquid crystal panel 110 is mounted on the panel support portion of the support main body 140 to adjust the transmittance of light supplied from the backlight unit 130 to realize an image. The liquid crystal panel 110 includes a first substrate 111 and a second substrate 112 which are bonded together with a liquid crystal layer (not shown) interposed therebetween. Although not shown in the drawings, a plurality of pixels may be defined on the first substrate 111, which is referred to as a TFT array substrate, by intersecting a plurality of scan lines and data lines in a matrix form. Each pixel is provided with a thin film transistor (TFT) capable of turning on / off a signal, and a pixel electrode connected to the thin film transistor may be positioned.

The second substrate 112, which is referred to as a color filter substrate, includes red (R), green (G), and blue (B) color filters respectively corresponding to a plurality of pixels, A black matrix for covering non-display elements such as transistors may be provided. Further, a transparent common electrode covering them may be provided. In the present embodiment, the pixel electrode is provided on the first substrate and the common electrode is provided on the second substrate. However, the present invention is not limited to this, and both the pixel electrode and the common electrode may be provided on the first substrate.

The printed circuit board 116 is connected to at least one side of the liquid crystal panel 110 via a connection member 114 such as a flexible circuit board or a tape carrier package (TCP) 140 or on the back surface of the bottom cover 150. [

In the liquid crystal panel 110 having the above structure, when the selected thin film transistor is turned on for each scan line by the on / off signal of the gate drive circuit transmitted from the scan line, the data voltage of the data drive circuit is transmitted through the data line The alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, and the difference in transmittance can be exhibited.

The support main 140 covers the edges of the light guide plate 200, the optical sheet 139 and the reflection sheet 128 and the light guide plate 200, the optical sheet 139 and the reflection sheet 128 to the bottom cover 150 And a function of supporting the liquid crystal panel 110. Here, the role of the support main body 140 may be replaced or omitted by the structure added to the top cover 160 and the bottom cover 150.

The liquid crystal display 100 of the present invention may include a backlight unit 130 capable of providing light from the back surface of the liquid crystal panel 110 to the liquid crystal panel 110. The backlight unit 130 includes a light source 120, a white or silver reflective sheet 128, a light guide plate 200 positioned on the reflective sheet 128, and a plurality of optical sheets (not shown) 139).

The light source 120 is mounted on a light source circuit board and is driven by a power source to generate light. The light source 120 may be formed of any one of a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), and an external electrode fluorescent lamp (EEFL). The light emitted from the light source 120 enters the inside of the light guide plate 200 and is supplied to the liquid crystal panel 110 by the light guide plate 200, the optical sheet 139 and the reflection sheet 128. The light source 120 is formed to face at least one side of the light guide plate 200. The LED assembly is disposed on one side of the light guide plate 200. The plurality of LED light sources 121 and the LED light sources 121 are spaced apart from each other by a predetermined distance, And a supporter 123 that can support the substrate 122 and the bottom cover 150.

On the other hand, in the present invention, it is advantageous that the backlight unit 130 is configured as an edge type. The light guide plate of the present invention induces the light emitted from the light source 120 to be totally reflected by not only the upper pattern and the light collecting sheet but also the lower pattern, thereby improving the brightness and preventing hot spots and bright lines.

The optical sheet 139 condenses or diffuses light emitted through the light guide plate 200 to be transmitted to the liquid crystal panel 110. To this end, the optical sheet 139 is configured to include at least one of a diffusion sheet or a light condensing sheet. The diffusion sheet prevents the light emitted through the light guide plate 200 from being concentrated in a part of the region and disperses light to be transmitted to the liquid crystal panel 110 with a uniform distribution. The light collecting sheet condenses the light emitted from the light guide plate 200 and allows light to be vertically transmitted to the liquid crystal panel 110. In particular, the light collecting sheet of the present invention may be constituted by a reverse prism sheet on which a sheet pattern is formed on the surface facing the light guide plate 200.

The reflective sheet 128 is disposed on the lower or side surface of the light guide plate 200 and reflects light emitted to the exit surface or the lower surface of the light guide plate 200 into the light guide plate 200. The reflective sheet 128 may be formed at different positions depending on the arrangement of the light sources 120. For example, as shown in FIG. 1, the edge type backlight unit may be disposed on the lower surface of the light guide plate 200, that is, on the surface facing the liquid crystal panel 110 with the light guide plate 200 interposed therebetween. The direct-type backlight unit may be formed on the side surface of the light guide plate 200 or may be omitted if necessary, and may be modified by various allowances such as the arrangement of the light sources 120 without being limited thereto.

The light guiding plate 200 spreads to a wide area of the light guide plate 200 to provide a primary surface light source to the liquid crystal panel 110 while the light incident from the light source 120 travels through the light guide plate 200 by total reflection several times can do. The light guide plate 200 may include a pattern of a specific shape on the back surface to supply a uniform surface light source.

The liquid crystal panel 110 and the backlight unit 130 may be modularized through the top cover 160, the support main 140 and the bottom cover 150. [ The top cover 160 may have a rectangular frame shape covering the top and side surfaces of the liquid crystal panel 110 and may open the front surface of the top cover 160 to display an image formed on the liquid crystal panel 110. The bottom cover 150 serves as a base for the liquid crystal display device by coupling the liquid crystal panel 110 and the backlight unit 130, and may be formed into a rectangular plate shape.

The configuration of the light guide plate described above will be described more specifically with reference to the following drawings.

FIG. 2 is a perspective view showing a front surface of a light guide plate according to an embodiment of the present invention, FIG. 3 is a perspective view showing a back surface of the light guide plate of FIG. 2, FIG. 4 is a cross- FIG. 6 is a photograph showing the first lower pattern of the light guide plate. FIG.

2 to 4, an upper pattern 210 and a lower pattern 220 are formed on the upper and lower surfaces of the light guide plate 200, respectively. The upper pattern 210 is formed on the upper surface of the light guide plate 200. The upper pattern 210 is formed in a prism pattern. The prism pattern may have a triangular shape in cross section and be linearly formed along the longitudinal direction of the prism pattern, so that the prism pattern may be formed in the shape of a triangular prism bar in appearance. However, the present invention is not limited thereto. The upper pattern 210 serves to reflect light incident into the light guide plate 200 several times in the light guide plate 200 to be dispersed in a uniform distribution and to reflect light in the direction of the liquid crystal panel through reflection It plays a role.

3 and 4, the lower patterns 220 are formed on the lower surface of the light guide plate 200. As shown in FIG. The lower patterns 220 are formed on the lower surface of the light guide plate 200 in a concave shape and a convex shape. More specifically, the lower surface of the light guide plate 200 can be largely divided into three regions, i.e., the light-incident portion A, the mixture portion B, and the reflection portion C. [ The light incident portion A is a portion where the light emitted from the light source 120 is incident on the light guide plate 200 and is the region where the brightness of light is the highest. The mixed portion B may be a region disposed adjacent to the light incident portion A and outgoing as the light incident through the light incident portion A is totally reflected. The reflective portion C occupies most of the area of the light guide plate 200 and may be a region in which the light totally reflected in the light guide plate 200 is condensed and emitted onto the upper surface of the light guide plate 200.

More specifically, referring to FIG. 5, a plurality of first lower patterns 230 are formed in the light-incident portion A of the light guide plate 200. The plurality of first lower patterns 230 have a hemispherical shape of a negative angle. The degree of diffraction, the degree of refraction, the focusing ability, and the like may be varied depending on the size and the compactness of the hemispherical surface of the first lower pattern 230. The pitch (P) between the first lower patterns 230 may be uniformly spaced or irregularly spaced. The diameter L or the length D of the first lower pattern 230 may be constant or irregular. In addition, the first lower pattern 230 may have a distribution of 50 to 90% or more in the entire area of the light-incident portion A, but the present invention is not limited thereto. In addition, the first lower patterns 230 may have the same depth without any difference in depth, or may have different depths.

When the first lower pattern 230 is formed to have a hemispherical surface of an engraved surface, part of the light incident through the incident surface 205 of the light guide plate 200 may be uniformly refracted at all azimuth angles have. Accordingly, some of the light reaching the hemispherical surface of the first lower pattern 230 may be uniformly diffused upward and condensed.

The light incident portion A of the light guide plate 200 may be a region ranging from the incident surface 205 of the light guide plate 200 to within 10% of the length of the light guide plate 200. [ The light incident portion A is the region closest to the light source 120 and the light emitted from the light source 120 has the highest luminance. Accordingly, there is a problem that hotspots with too high luminance are generated in the light-incident portion A of the light guide plate 200. [ Therefore, in the present invention, by forming a plurality of first lower patterns 230 in a region within 10% of the length of the light guide plate 200 from the incident surface 205 of the light guide plate 200, There is an advantage that it can be removed.

A plurality of first lower patterns 230 and a plurality of second lower patterns 240 are formed in a mixed portion B of the light guide plate 200. Since the first lower pattern 230 has been described above, the second lower pattern 240 will be described below. FIGS. 7 and 8 are a perspective view and a sectional view showing second lower patterns of the light guide plate, and FIG. 9 is a photograph showing a second lower pattern formed on the light guide plate.

Referring to FIGS. 7 to 9, the plurality of second lower patterns 240 are formed in an asymmetric three-dimensional shape. An inclined surface 247a having one or more surfaces for reflecting light is formed. Further, another sub-slope 247b facing the slope 247a may be formed, and the slope 247a and the sub-slope 247b forming the base are not parallel to each other. The sub-slope 247b may be formed at a right angle to the base, but is not limited thereto. The lower pattern 240 may be formed in a shape similar to a prism, and an inclined plane 247a and a sub-inclined plane 247b are formed asymmetrically for total reflection.

The second lower pattern 240 may be engraved on the lower surface of the light guide plate 200 or may be formed in a plurality of embossed shapes. Referring to FIG. 7A, when the second lower pattern 240 is formed at a negative angle, the inclined plane 246a is formed to face the incident plane 205 on which light is incident. 7 (b), when the second lower pattern 240 is formed with a positive angle, the sub-scan surface 246b is formed to face the incident surface 205. [ The light entering the light guide plate 200 is totally reflected by the inclined surface 246a and is emitted to the light guide plate 200 through the incident surface 205.

Referring to FIG. 8, the second lower pattern 240 of the present invention exits the light traveling in the light guide plate 200 through the light guide plate. Specifically, when the light emitted through the entire surface of the light guide plate 200 maintains a constant emission angle with respect to the entire surface of the light guide plate 200, the light collection efficiency increases and the luminance increase effect can be expected.

The slope angle? 1 formed by the inclined surface 246a and the lower surface 206 of the light guide plate 200 is smaller than the inclined angle? 1 between the slope surface 246b and the lower surface of the light guide plate 200 (&Amp;thetas; 1 <&amp;thetas; 2). More specifically, the inclination angle? 1 may be an angle within a range of 5 to 10 degrees so as to facilitate the total reflection effect and the exit angle to be emitted at a specific angle of 10 to 30 degrees. An angle? 3 between the inclined plane 246a and the sub-inclined plane 246b may be an angle of 50 degrees or more and 170 degrees or less. In this case, the total reflection effect is deteriorated and the brightness enhancement effect is lowered, so that the second lower pattern 240 is formed in such a manner that the inclination angle? 1, the parabolic slope angle? 2 and the angle? 3 are different from each other. It is difficult to expect an improvement in the effect of the above. In addition, as described above, the inclined surface 246a of the lower pattern 240 is disposed in a form for reflection of light incident through the incident surface 205 of the light guide plate 200. [

Referring again to FIGS. 3 and 4, the first lower pattern 230 and the second lower pattern 240 are mixed in the mixing portion B of the light guide plate 200 described above. The mixing portion B serves to prevent a bright line from being generated due to a difference in brightness of light at the boundary between the light entrance portion A and the reflection portion C of the light guide plate 200. [ Accordingly, the first lower pattern 230 for diffusing light to make the brightness uniform and the second lower pattern 240 for improving the brightness by reflecting the light are uniformly mixed with the mixed portion B to generate a bright line &Lt; / RTI &gt;

3, the first lower pattern 230 and the second lower pattern 240 may be regularly arranged alternately in the mixing portion B, but the present invention is not limited thereto, Any arrangement is acceptable as long as luminance uniformity can be achieved. It is preferable that the area occupied by the first lower pattern 230 and the second lower pattern 240 in the mixing portion B is 50:50. However, if the brightness uniformity can be achieved while properly diffusing the light, The area occupied by the lower pattern 230 may be larger than the area occupied by the second lower pattern 240 or the area occupied by the second lower pattern 240 may be larger than the area occupied by the first lower pattern 230 .

In addition, the first lower pattern 230 and the second lower pattern 240 of the mixing portion B may be overlapped with each other. 10 is a photograph showing the first lower pattern and the second lower pattern formed on the light guide plate. Referring to FIG. 10, the first lower pattern 230 may be disposed to be spaced apart from the second lower pattern 240 while being overlapped with the second lower pattern 240. That is, the first lower pattern 230 may be further formed on the second lower pattern 240. However, the present invention is not limited to this, and the first lower pattern 230 and the second lower pattern 240 may have any structure as long as luminance uniformity can be achieved in the mixed portion (B).

The mixing portion B may be an area ranging from 10% to 30% of the length of the light guide plate 200 from the incident surface 205 of the light guide plate 200. [ The mixing portion B is formed in a range that can reduce a difference in brightness of light at the boundary between the light entrance portion A and the reflection portion C of the light guide plate 200 and the first lower pattern 230 and the second lower pattern 240) are uniformly mixed to prevent bright lines from being generated.

The plurality of second lower patterns 240 are formed on the reflective portion C of the light guide plate 200. The reflective portion C of the light guide plate 200 may be a region other than the light incident portion 205 of the light guide plate 200 except for a region up to 30% of the length of the light guide plate 200. [ The reflective portion C serves to reflect the light in the light guide plate 200 to the upper surface of the light guide plate 200. The total reflection of the light incident into the light guide plate 200 due to the plurality of second lower patterns 240, Thereby improving the efficiency and increasing the light utilization efficiency and brightness.

11 is a cross-sectional view for explaining the light path by the lower pattern in the light guide plate. Referring to FIG. 11, when light is incident from the light source 120 through the incident surface 205 of the light guide plate 200, the light reaches the light incident portion A of the light guide plate 200. The light incident on the light-incident portion A is diffused by the plurality of first lower patterns 230 formed on the light- The light reaching the mixing portion B is partially diffused by the plurality of first lower patterns 230 formed in the mixing portion B and part of the light is diffused by the plurality of second lower patterns 240 As shown in FIG. The light reaching the reflection portion C is reflected upward by the plurality of second lower patterns 240 formed on the reflection portion C and a part of the light is emitted to the outside through the upper surface of the light guide plate 200 .

As described above, the light guide plate of the present invention has a light-entering portion, a mixing portion, and a reflecting portion, and by forming a plurality of first lower patterns 230 and a second lower pattern 240, hot spots There is an advantage that it is possible to prevent a bright line due to a difference in luminance from occurring.

13 is a view showing a method of forming an upper pattern on a light guide plate, FIG. 14 is a photograph showing a second lower pattern, and FIGS. 15 to 17 are views showing a method of manufacturing a light guide plate according to the present invention. FIG. 18 is a view showing a method of manufacturing a first lower pattern on a light guide plate, and FIG. 19 is a photograph showing a first lower pattern.

Referring to FIGS. 12 to 14, a method of manufacturing a backlight unit according to the present invention includes a base preparation step (S10), an upper pattern formation step (S20), and a lower pattern formation step (S30).

The base preparing step S10 is a step of preparing a base which is a base material of the light guide plate. The upper pattern formation step S20 is a step of forming the upper pattern 210 on the base prepared in the base preparation step S10 as shown in FIG. In the upper pattern forming step S20, the upper surface of the base 250 is cut by the cutting tip 260 to form a groove, thereby forming an upper pattern.

The first lower pattern 230 and the second lower pattern 240 are formed on the lower surface of the base 250 in the lower pattern formation step S30. First, the manufacturing method is changed depending on whether the second lower pattern 240 is embossed or embossed. Specifically, in the case of forming the second lower pattern with the engraved pattern, the second lower pattern can be formed by machining the previously designated position by the punching method using the cutting tip. That is, only the second lower pattern formation position is partially formed to form the second lower pattern of the engraved as shown in FIG. 14 on the lower surface of the light guide plate.

15 to 17, the second lower pattern 240 may be formed to include a lower cutting step and a flat forming step. 15, grooves are formed in the lower surface of the light guide plate 200 using the cutting tip 260 to form a line pattern 247 in which a slope 246a and a sub-slope 246b are connected to each other in one direction .

The flattening step is a step of separating the line pattern 247 to form a pattern formed by the line pattern 247 into each separated second lower pattern 240 as shown in FIG. The flattening step may be performed by cutting the bottom surface of the light guide plate 200 on which the line pattern 247 is formed by the cutting tip 260 in a direction intersecting the line pattern 247 or in a side- do. A planar portion 248 is formed along the direction in which the cutting tip 260 is moved and a pattern formed in the form of a line pattern 247 by the flat portion 248 is separated and formed by the respective second lower patterns 240 .

Particularly, as shown in FIG. 17, the second lower pattern 240 includes a tilting process in which the light guide plate 200 is formed at a predetermined angular slope with respect to the vertical axis Hx or the horizontal axis Vx. 17 shows an example in which the tilting is performed in the longitudinal axis Hx direction by the cutting tip 260 on the longitudinal axis Hx. However, the present invention is not limited thereto, and the same applies also to the transverse axis Vx direction It is possible to tilt the second lower pattern 240.

Referring to FIGS. 18 and 19, in the lower pattern forming step S30, the first lower pattern 230 is formed after the second lower pattern 240 is formed. The first lower pattern 230 is formed using the laser device 270 having the scan head 280 as the dimpled hemispherical patterns. That is, the laser beam irradiated through the scan head 280 from the laser device 270 may be directly irradiated to the lower surface of the light guide plate 200 to form the first lower pattern 230. Accordingly, as shown in FIG. 19, first lower patterns 230 by laser irradiation can be formed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the present invention should not be limited to the details described in the detailed description, but should be defined by the claims.

100: liquid crystal display device 110: liquid crystal panel
120: light source 128: reflective sheet
130: backlight unit 139: optical sheet
140: Support main 150: Bottom cover
160: Top cover 200: Light guide plate

Claims (13)

A light source for providing light; And
And a second lower pattern disposed between the light-incident portion and the reflective portion, the first and second lower patterns being disposed between the light-incident portion and the reflection portion, And a light-guiding plate including a mixing portion including a light-shielding portion.
The method according to claim 1,
Wherein the light-incident portion is an area from an incident surface of the light guide plate through which light is incident from the light source to 10% of the length of the light guide plate.
3. The method of claim 2,
Wherein the first lower pattern is hemispherical in shape.
3. The method of claim 2,
Wherein the reflective portion is a region other than the region from the incident surface to 30% of the length of the light guide plate.
5. The method of claim 4,
Wherein the second lower pattern is formed by embossing or embossing.
6. The method of claim 5,
Wherein the second lower pattern is formed into a prism shape by an inclined surface and a sub-surface.
The method according to claim 6,
Wherein the slope angle formed by the slope and the lower surface of the light guide plate is smaller than the slope angle formed by the lower surface and the sub-slope.
The method according to claim 6,
Wherein the inclined surface is positioned closer to the incident surface of the light guide plate than the sub-inclined surface.
The method according to claim 1,
Wherein the first lower pattern and the second lower pattern are regularly or irregularly arranged in the mixing portion.
A light source for providing light;
And a second lower pattern disposed between the light-incident portion and the reflective portion, the first and second lower patterns being disposed between the light-incident portion and the reflection portion, A light guide plate including a mixing portion including a light guide plate;
An optical sheet positioned on the light guide plate; And
And a liquid crystal panel disposed on the optical sheet and implementing an image.
A base preparing step of a light guide plate having a light-entering portion, a mixing portion, and a reflecting portion;
Forming a second lower pattern in the mixing portion and the reflection portion of the bottom surface of the base; And
And forming a first lower pattern in the light-incident portion and the mixing portion of the bottom surface of the base.
12. The method of claim 11,
The forming of the first lower pattern may include:
Wherein the base is directly irradiated with a laser to form a first lower pattern.
12. The method of claim 11,
Wherein forming the second lower pattern comprises:
A lower cutting step of cutting the lower surface of the base to form an inclined surface and a sub-inclined surface; And
And forming a flat portion by re-cutting the base on which the inclined plane and the sub-inclined plane are formed.
KR1020130076038A 2013-06-28 2013-06-28 BackLight Unit and Liquid Crystal Display device Comprising The Same KR102053438B1 (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20080004140A (en) * 2006-07-04 2008-01-09 삼성에스디아이 주식회사 A light guided panel

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20080004140A (en) * 2006-07-04 2008-01-09 삼성에스디아이 주식회사 A light guided panel

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