KR20110071037A - Light guide member and display device having the same - Google Patents

Abstract

PURPOSE: A light guiding unit and a displaying apparatus including the same are provided to efficiently diffuse light radiated to a light guiding unit by including a diffusing pattern and a diffusing layer. CONSTITUTION: A light guiding part(231) is formed into a plate shape. A diffusing pattern(232) diffuses incident light. The size of the diffusing pattern is changed according to the distance with respect to a light emitting diode(240). A diffusing layer(233) is arranged at the lower side of the light guiding part. A reflecting layer(234) based on aluminum, platinum, silver, or the alloy of the same reflects light from the light emitting diode to the upper side.

Description

LIGHT GUIDE MEMBER AND DISPLAY DEVICE HAVING THE SAME}

Embodiments relate to a light guide member and a display device including the same.

Cathode ray tube (CRT), one of the widely used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices, but the size and weight of electronic products are reduced due to the weight and size of CRT itself. Could not actively respond to the response.

Therefore, in the trend of miniaturization and weight reduction of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display (LCD) and gas discharge using electro-optic effects. Plasma Display Panel (PDP) and Electro Luminescence Display (ELD) using the electroluminescent effect, and the like, among them, researches on liquid crystal displays are being actively conducted.

BACKGROUND ART Liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. Accordingly, in order to meet the needs of users, liquid crystal display devices are progressing in the direction of large area, thinning, and low power consumption.

BACKGROUND ART A liquid crystal display device is a display device that displays an image by controlling an amount of light passing through a liquid crystal, and is widely used for advantages such as thinning and low power consumption.

Unlike the CRT, the liquid crystal display is not a display device that emits light by itself, and thus, a back light unit including a separate light source is provided on the rear surface of the liquid crystal display panel to provide light for visually representing an image. .

The backlight unit is classified into an edge method and a direct method according to the position of the light source.

In particular, the edge type backlight unit is mainly applied to a liquid crystal display device having a relatively small size, such as a monitor of a laptop computer and a desktop computer, and has good light uniformity, long life, and an advantage in thinning a liquid crystal display device. Has

The edge type backlight unit requires a light guide member for guiding light and improving light uniformity.

Embodiments provide an optical guide member for improving luminance uniformity and improving image quality, and a display device including the same.

In one embodiment, a light guide member includes: a light guide portion; A diffusion pattern disposed on a bottom surface of the light guide portion; And a diffusion layer coated on a lower surface of the light guide part and covering the diffusion pattern.

In one embodiment, a display device includes: a display panel; A light guide plate disposed under the display panel; And a light source disposed at a side of the light guide plate, wherein the light guide plate comprises: a light guide portion; A diffusion pattern disposed on a bottom surface of the light guide portion; And a diffusion layer coated on a lower surface of the light guide part and covering the diffusion pattern.

The light guide member according to the embodiment includes a diffusion pattern and a diffusion layer. Accordingly, the light incident on the light guide member according to the embodiment can be efficiently diffused. Accordingly, the light guide member according to the embodiment may implement improved brightness uniformity, and the display device according to the embodiment also has improved brightness uniformity and improved image quality.

 In addition, a reflective layer may be coated on the lower surface of the diffusion layer, and the diffusion layer may perform a buffer function between the light guide portion and the reflective layer.

Therefore, the optical guide member according to the embodiment can prevent cracks, etc., generated when bent, and can suppress defects.

In the description of the embodiment, each panel, member, plate, sheet, cover, or layer is formed on or under the "on" of each panel, member, plate, sheet, cover, or layer, or the like. When described as being "in" and "under" includes both those that are formed "directly" or "indirectly" through other components. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a perspective view illustrating a liquid crystal display according to an embodiment. 2 is a perspective view illustrating a rear surface of the light guide plate. FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG. 2. 4 is an enlarged cross-sectional view of a diffusion pattern and a diffusion layer. 5 and 6 are cross-sectional views illustrating cross-sectional views of light guide plates according to another exemplary embodiment.

1 to 3, the liquid crystal display according to the embodiment includes a liquid crystal display panel 100 and a backlight unit 200.

The liquid crystal display panel 100 includes a color filter substrate and a thin film transistor substrate bonded together to maintain a uniform cell gap facing each other, and a liquid crystal layer interposed between the two substrates.

Although not shown in detail in the drawings, the color filter substrate and the thin film transistor substrate will be described in detail. In the thin film transistor substrate, a plurality of gate lines and data lines cross each other to define pixels, and thin film transistors (TFTs) are formed at respective crossing regions. A thin flim transistor) is provided and connected in a one-to-one correspondence with the pixel electrode mounted on each pixel. The color filter substrate includes a color filter of R, G, and B colors corresponding to each pixel, a black matrix bordering each of them, and covering a gate line, a data line, a thin film transistor, and the like, and a common electrode covering all of them.

On the side of the liquid crystal display panel 100, a gate driver (not shown) connected to the gate line and the data line of the liquid crystal display panel 100 to supply a scan signal to the gate line, and a data signal to the data line. A data driver (not shown) is provided.

The gate and data driver are electrically connected to each other by a tap formed of a tape carrier package (TCP).

The gate and data driver are electrically connected to the liquid crystal display panel 100 to supply scan signals and data signals to a plurality of gate lines and data lines formed in the liquid crystal display panel 100, thereby providing the liquid crystal display panel 100. Drive pixels.

In addition, the liquid crystal display according to the embodiment includes a support main 101 supporting an edge of the liquid crystal display panel 100.

The backlight unit 200 is disposed under the liquid crystal display panel 100. The backlight unit 200 generates light and emits the light toward the liquid crystal display panel 100. The backlight unit 200 includes a bottom cover 210, a light guide plate 230, a plurality of light emitting diodes 240, a printed circuit board 250, and a plurality of optical sheets 260.

The bottom cover 210 has a box shape with an upper surface opened. The bottom cover 210 may accommodate the light guide plate 230, the light emitting diodes 240, the printed circuit board 250, and the optical sheets 260. In addition, the bottom cover 210 may support the liquid crystal display panel 100.

The light guide plate 230 is disposed inside the bottom cover 210. The light guide plate 230 receives light emitted from the light emitting diodes 240 and uniformly emits light upward through refraction, scattering, and reflection. That is, the light guide plate 230 converts the point light emitted from the light emitting diodes 240 into surface light.

In other words, the light guide plate 230 guides the light emitted from the light emitting diodes 240 and emits upward. That is, the light guide plate 230 is a light guide member.

As illustrated in FIGS. 2 and 3, the light guide plate 230 includes a light guide part 231, a diffusion pattern 232, a diffusion layer 233, and a reflection layer 234.

The light guide portion 231 has a plate shape. The light guide portion 231 is transparent. The refractive index of the light guide portion 231 may be about 1.30 to about 1.60. Examples of the material used as the light guide portion 231 include polymethyl methacrylate (PMMA) or polycarbonate (PC).

The diffusion pattern 232 is disposed under the light guide portion 231. The diffusion pattern 232 is disposed on the bottom surface of the light guide portion 231. The diffusion pattern 232 is adhered to the bottom surface of the light guide portion 231. That is, the diffusion pattern 232 is printed on the bottom surface of the light guide portion 231.

The diffusion pattern 232 may be disposed over the entire lower surface of the light guide portion 231. The size of the diffusion pattern 232 increases as the distance from the light emitting diodes 240 increases. In other words, the diameter of the diffusion pattern 232 increases as the distance from the light emitting diodes 240 increases.

As shown in FIG. 4, the diffusion pattern 232 includes a first transparent resin layer 232a and first diffusion particles 232b.

The first transparent resin layer 232a is transparent and is attached to the lower surface of the light guide portion. The first transparent resin layer 232a may include an infrared curing ink or an ultraviolet curing ink.

The first diffusion particles 232b are uniformly dispersed inside the first transparent resin layer 232a. The first diffusion particles 232b may have a color. Alternatively, the first diffusion particles 232b may be transparent particles having a refractive index different from that of the first transparent resin layer 232a.

In addition, the first diffusion particles 232b may be metal particles having high reflectance. The diameter of the first diffusion particles 232b may be, for example, 100 nm to 10 μm.

The diffusion pattern 232 diffuses the incident light. That is, the diffusion pattern 232 diffuses the incident light and exits upward.

In addition, the diffusion pattern 232 scatters incident light. That is, the diffusion pattern 232 changes the path of incident light by scattering. Accordingly, the light scattered by the diffusion pattern 232 is emitted upward.

The diffusion layer 233 covers the diffusion pattern 232. The diffusion layer 233 is disposed under the light guide portion 231. The diffusion layer 233 is disposed on the bottom surface of the light guide portion 231. The diffusion layer 233 is coated on the bottom surface of the light guide portion 231.

The diffusion layer 233 is in direct contact with the side surface of the diffusion pattern 232. That is, the diffusion layer 233 is in close contact with the bottom surface of the light guide portion 231 and the side surface of the diffusion pattern 232. Accordingly, no air layer exists between the diffusion layer 233 and the light guide portion 231 and between the diffusion layer 233 and the diffusion pattern 232.

The diffusion layer 233 includes a second transparent resin layer 233a and second diffusion particles 233b.

The second transparent resin layer 233a is transparent and is attached to the lower surface of the light guide portion. The second transparent resin layer 233a covers the diffusion pattern 232. The second transparent resin layer 233a may include an infrared curing ink or an ultraviolet curing ink.

The second diffusion particles 233b are uniformly dispersed inside the second transparent resin layer 233a. The second diffusion particles 233b may have a color. Alternatively, the second diffusion particles 233b may be transparent particles having a refractive index different from that of the second transparent resin layer 233a.

In addition, the second diffusion particles 233b may be metal particles having high reflectance. The diameters of the second diffusion particles 233b may be, for example, about 100 nm to about 10 μm. The diffusion layer 233 may have a thickness of about 10 μm to about 50 μm.

The refractive index of the diffusion layer 233 may correspond to the refractive index of the light guide portion 231. That is, the refractive index of the diffusion layer 233 may be substantially the same as the refractive index of the light guide portion 231. In this case, the refractive index of the diffusion layer 233 may be about 1.45 to 1.6.

In addition, the refractive index of the diffusion layer 233 may correspond to the refractive index of the diffusion pattern 232. That is, the refractive index of the diffusion layer 233 may be substantially the same as the refractive index of the diffusion pattern 232.

Alternatively, the refractive index of the diffusion layer 233 may be smaller than the refractive index of the light guide portion 231. In addition, the refractive index of the diffusion layer 233 may be smaller than the refractive index of the diffusion pattern 232.

The density of the first diffusion particles 232b may be higher than the density of the second diffusion particles 233b. That is, when comparing the number of the first diffusion particles and the second diffusion particles included in the first transparent resin layer and the second transparent resin layer of the same volume, the first diffusion particles 232b are more 1 is contained in the transparent resin layer 232a.

Accordingly, the diffusion of the light of the diffusion pattern 232 is greater than the diffusion of the diffusion layer 233.

The reflective layer 234 is disposed below the diffusion layer 233. In more detail, the reflective layer 234 is coated on the bottom surface of the diffusion layer 233. In more detail, the reflective layer 234 is coated on the entire lower surface of the diffusion layer 233. That is, the reflective layer 234 is in close contact with the bottom surface of the diffusion layer.

The reflective layer 234 reflects light emitted from the light emitting diodes 240 upward. The reflective layer 234 may include a metal having a high reflectance. Examples of the material used as the reflective layer 234 include platinum, aluminum, silver, or alloys thereof.

The reflective layer 234 may have a thickness of about 0.1 μm to about 10 μm.

As illustrated in FIG. 5, the light guide portion 231 may have a concave first scattering pattern 235. That is, the first scattering pattern 235 is formed on the bottom surface of the light guide portion 231 to scatter the incident light.

In this case, the diffusion pattern 232 may be disposed corresponding to the first scattering pattern 235, and may be disposed regardless of the first scattering pattern 235.

The diffusion layer 233 covers the first scattering pattern 235 and the diffusion pattern 232. Accordingly, the diffusion layer 233 may have a bend. That is, the diffusion layer 233 may have an uneven shape.

Similarly, the reflective layer 234 may have an uneven shape corresponding to the unevenness of the diffusion layer 233.

As illustrated in FIG. 6, the light guide portion 231 may have a convex second scattering pattern 236. That is, the second scattering pattern 236 is formed on the bottom surface of the light guide portion 231 to scatter incident light.

In this case, the diffusion pattern 232 may be disposed corresponding to the second scattering pattern 236, and may be disposed regardless of the second scattering pattern 236.

The diffusion layer 233 covers the second scattering pattern 236 and the diffusion pattern 232. Accordingly, the diffusion layer 233 may have a bend. That is, the diffusion layer 233 may have an uneven shape.

Similarly, the reflective layer 234 may have an uneven shape corresponding to the unevenness of the diffusion layer 233.

The light emitting diodes 240 are arranged in a line on the side surface of the light guide plate 230. In more detail, the light emitting diodes 240 are disposed on the side surface of the light guide portion 231. The light emitting diodes 240 generate light and exit toward the side surface of the light guide portion 231. That is, the light emitting diodes 240 are light sources for generating light.

The light emitting diodes 240 may include a light emitting diode 240 emitting white light or a combination of light emitting diodes 240 emitting red, green, and blue light, or light emitting diodes 240 emitting white, red, green, and blue light. ) May be combined.

The light emitting diodes 240 may be disposed only on one side of the light guide portion 231. Alternatively, the light emitting diodes 240 may be disposed on two or more side surfaces of the light guide portion 231.

Instead of the light emitting diodes 240, a lamp, such as a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL), may be disposed as a light source on the side of the light guide plate 230. have.

The printed circuit board 250 is electrically connected to the light emitting diodes 240. That is, the light emitting diodes 240 are mounted on the printed circuit board 250 to receive a driving signal through the printed circuit board 250.

The optical sheets 260 may include a diffusion sheet 261 for diffusing light, a light collecting sheet 262 for collecting the diffused light, and a protective sheet for protecting the light collecting pattern formed on the light collecting sheet 262. 263).

The light guide plate diffuses light efficiently by the diffusion pattern 232 and the diffusion layer 233. In addition, the light guide plate efficiently scatters light incident from the light emitting diodes 240 by the first scattering pattern 235 or the second scattering pattern 236.

Accordingly, the light guide plate may implement high luminance uniformity. In particular, the portion where the first scattering pattern 235 or the second scattering pattern 236 is disposed has a high luminance, and the diffusion pattern 232 can mitigate such luminance unevenness.

In addition, the diffusion layer 233 has a lower level of diffusing light than the diffusion pattern 232. In addition, since the size of the diffusion pattern 232 increases as the diffusion pattern closer to the light emitting diodes has a high degree of diffusing light, the luminance of a region close to the light emitting diodes 240 increases. Is prevented.

Thus, the liquid crystal display according to the embodiment has improved luminance uniformity and improved image quality.

In addition, the diffusion layer 233 may have a higher elasticity than the light guide portion 231. That is, the diffusion layer 233 may be more flexible than the light guide portion 231.

Accordingly, the diffusion layer 233 may perform a buffer function between the light guide portion 231 and the reflective layer 234.

Therefore, when the light guide plate 230 is bent, no crack is generated between the reflective layer 234 and the diffusion layer.

In addition, the diffusion layer 233 and the reflective layer 234 cover the diffusion pattern 232 and protect the diffusion pattern 232. Therefore, the diffusion pattern 232 may be prevented from being damaged by the diffusion layer 233 and the reflective layer 234. For example, the diffusion pattern 232 may be damaged by friction and / or contact with the bottom cover 210. In this case, the diffusion layer 233 and the reflective layer 234 are interposed between the diffusion pattern 232 and the reflective sheet 220 to protect the diffusion pattern 232.

Thus, the liquid crystal display according to the embodiment has improved strength.

7 to 9 are cross-sectional views illustrating a process of manufacturing a light guide plate according to an embodiment. Regarding the manufacturing method of the light guide plate, the description of the above light guide plate is referred to. The foregoing description of the LGP may be essentially combined with the description of the manufacturing method of the LGP.

Referring to FIG. 7, the diffusion pattern 232 is printed on the light guide portion 231. In order to form the diffusion pattern 232, a first resin composition including first diffusion particles 232b is printed on the light guide portion 231. The first resin composition includes an infrared curing ink or an ultraviolet curing ink.

In this case, the first resin composition is printed on the light guide portion 231 by an inkjet process or a silk printing process.

Thereafter, the first resin composition printed on the light guide part 231 is cured by infrared rays or ultraviolet rays, and the diffusion pattern 232 is formed.

Referring to FIG. 8, a second resin composition including second diffusion particles 233b is coated on the light guide portion 231. The second resin composition may be formed by a spin coating process or the like. In addition, the second resin composition is coated while covering the diffusion pattern 232.

The second resin composition may include an infrared curable material and / or an ultraviolet curable material. In addition, the second resin composition may include a monomer or an oligomer.

Thereafter, the resin composition is cured by infrared rays and / or ultraviolet rays, and a diffusion layer 233 is formed on the light guide portion 231.

Referring to FIG. 9, a material having a high reflectance is coated on the diffusion layer 233. For example, silver, aluminum, platinum, or an alloy thereof is deposited on the diffusion layer 233 by a sputtering process, a chemical vapor deposition process, a thermal transfer process, or the like to form a reflective layer 234.

After the diffusion pattern 232, the diffusion layer 233, and the reflective layer 234 are formed, the light guide portion 231 is inverted to form the light guide plate 230 described above.

In addition, the features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a perspective view illustrating a liquid crystal display according to an embodiment.

2 is a perspective view illustrating a rear surface of the light guide plate.

FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG. 2.

4 is an enlarged cross-sectional view of a diffusion pattern and a diffusion layer.

5 and 6 are cross-sectional views illustrating cross-sectional views of light guide plates according to another exemplary embodiment.

7 to 9 are cross-sectional views illustrating a process of manufacturing a light guide plate according to an embodiment.

Claims (10)

Light guide part; A diffusion pattern disposed on a bottom surface of the light guide portion; And And a diffusion layer coated on a lower surface of the light guide part and covering the diffusion pattern. The light guide member of claim 1, further comprising a reflective layer coated on a lower surface of the diffusion layer. The light guide member of claim 2, wherein the reflective layer comprises aluminum, platinum, silver, or an alloy thereof. The method of claim 1, wherein the diffusion pattern includes first diffusion particles at a first density, the diffusion layer includes second diffusion particles at a second density, And the first density is greater than the second density. The light guide member of claim 1, wherein the light guide portion is flexible. The light guide member of claim 1, wherein a scattering pattern is formed on a bottom surface of the light guide portion. Display panel; A light guide plate disposed under the display panel; And It includes a light source disposed on the side of the light guide plate, The light guide plate is Light guide part; A diffusion pattern disposed on a bottom surface of the light guide portion; And And a diffusion layer coated on a lower surface of the light guide portion and covering the diffusion pattern. The display device of claim 7, wherein the planar area of the diffusion pattern increases as the distance from the light source increases. The method of claim 7, further comprising a reflective layer coated on the lower surface of the diffusion layer, The diffusion layer is more flexible than the light guide portion. The display device of claim 9, wherein the reflective layer has irregularities.

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