KR20110026903A - Backlight unit and display apparatus including the same - Google Patents

Abstract

PURPOSE: A backlight unit and a display apparatus are provided to improve a display quality by offering a backlight unit with uniform brightness. CONSTITUTION: A backlight unit of a display device comprises a substrate, a plurality of light sources(212) placed on the substrate, a resin layer(230) including a groove(231) in which the light source is inserted, and a light diffusing unit(231b) for diffusing light from a light source. An inner surface of the groove is separated from a light emitting part. The resin layer is closely adhere to an upper part of the substrate. A reflection sheet is attached to the substrate.

Description

Backlight unit and display apparatus including the same {Backlight unit and display apparatus including the same}

The present invention relates to a backlight unit and a display device including the same.

In general, liquid crystal displays (LCDs) are increasingly wider in application due to features such as light weight, thinness, and low power consumption. In accordance with this trend, the liquid crystal display is widely used in cellular phones, notebook computers, monitors, TVs, and lighting fields.

Since the liquid crystal display is not a self-luminous display device, it includes a display panel for displaying an image and a display module having a backlight unit disposed on a rear surface of the display panel to provide light.

The backlight unit may be divided into a direct method and an edge method according to the position of the light source.

In the edge method, the light source is disposed on the side of the display module, and the light emitted from the light source is irradiated onto the entire surface of the display panel using a light guide plate. On the other hand, in the direct method, a plurality of light sources are disposed on the back of the display panel to directly irradiate light directly under the display panel, so that the luminance can be increased by a plurality of light sources compared to the edge method, and the light emitting surface is wider. There is an advantage to this.

On the other hand, in recent years, a backlight unit using a light emitting diode (LED) as the light source has been released. The light emitting diode is miniaturized and thinned by applying a fine semiconductor process, and thus is used to implement a thinner and lighter display module than a display module using a cold cathode fluorescent lamp (CCFL).

However, the above conventional technology has the following problems.

The direct type backlight unit has a problem in that it is difficult to realize uniform luminance because a difference in luminance occurs between a region where the light source is disposed and a region where the light source is not disposed.

In particular, there is a problem in that a hot spot having a higher luminance than the surroundings is generated in a region where the light source is disposed.

In order to solve this problem, when increasing the distance between the display panel and the backlight unit, or increasing the distance between the diffusion plate and the optical sheets disposed in the backlight unit, the thickness of the display module There is a problem of thickening.

In addition, since the light emitting diode is small in size, the amount of light (light flux) to be supplied is small, and thus a large number of light emitting diodes of hundreds to thousands of light emitting diodes is required when a large size direct-type backlight unit is manufactured. Therefore, there is a problem that the manufacturing cost is increased.

The present invention has been proposed to solve the above problems, and an object thereof is to provide a thin back light unit and a display device including the same.

Another object of the present invention is to provide a backlight unit having a uniform brightness and a display device including the same.

In addition, an object of the present invention is to provide a backlight unit and a display device including the same, in which manufacturing cost is reduced.

A backlight unit according to an embodiment of the present invention for achieving the above object, the substrate; A plurality of light sources disposed on the substrate; And a resin layer formed recessed from below, wherein the resin layer in which the groove into which the light source can be inserted is formed is formed, the inner circumferential surface of the groove is spaced apart from the light emitting surface of the light source, and the inner circumferential surface of the groove is radiated from the light source. A scattering unit for scattering light is formed.

In another aspect, a display device includes a display module including a backlight unit and a display panel disposed on a front surface of the backlight unit; A front cover to which the display module is fixed; And a back cover covering a rear surface of the display module, wherein the backlight unit is in close contact with the display panel.

According to the backlight unit and the display device including the same according to the embodiment of the present invention as described above, since the improved backlight unit structure is provided, there is an advantage that the thickness of the backlight unit and the display device can be made thin.

In addition, there is an advantage that the thickness of the display device can be made thinner by closely attaching the backlight unit to the display panel.

In addition, there is an effect that the image quality can be improved by providing a backlight unit having a uniform brightness.

In addition, the manufacturing cost can be reduced by reducing the number of light emitting diodes used.

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

1 is an exploded perspective view schematically illustrating a configuration of a display device including a backlight unit according to a first embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of the display module of FIG. 1.

1 and 2, the display device 1 according to the first embodiment of the present invention includes a display module 20 for displaying an image, a front cover 12 surrounding the display module 20, and The back cover 12 may be included.

The front cover 11 may include a front panel (not shown) of a transparent material that transmits light, and the front panel may be disposed at a predetermined interval of the display module 20, particularly, the display panel 300 to be described later. It is disposed on the front surface, and protects the display module 20 from external impact, and transmits the light emitted from the display module 20 so that the image displayed on the display module 20 can be seen from the outside.

The back cover 12 may protect the rear of the display module 20 and may be fixed to the front cover 11. In particular, when the backlight unit 200 to be described later is provided in the form of a film, the back cover 12 may be fixed only to the front cover 11 without being combined with the display module 20 for firm fixing. .

The display module 20 includes a display panel 300 for displaying an image and a backlight unit 200 in close contact with a rear surface of the display panel 300 and irradiating light to the display panel 300.

The display panel 300 includes a thin film transistor (TFT) substrate 320, a color filter substrate 330, and two substrates 320 and 330 bonded to each other to maintain a uniform cell gap. A liquid crystal layer interposed therebetween, a lower polarizer 310 disposed on a bottom surface of the thin film transistor substrate 320, and an upper polarizer 340 disposed on an upper surface of the color filter substrate 330. Can be. Side of the display panel 300 is further provided with a gate and a data driver (not shown) for generating a driving signal for driving the display panel 300.

The color filter substrate 330 includes a plurality of pixels including red (R), green (G), and blue (B) sub-pixels. When light is applied, the color filter substrate 330 may display an image corresponding to a color of red, green, or blue. Generate.

On the other hand, the pixels are generally composed of red, green, and blue subpixels, but the red, green, blue, and white (W) subpixels constitute one pixel, but are not necessarily limited thereto. Can be.

The thin film transistor substrate 320 switches a pixel electrode (not shown) as a switching element. The common electrode (not shown) and the pixel electrode convert the arrangement of the molecules of the liquid crystal layer according to a predetermined voltage applied from the outside. The liquid crystal layer is composed of a plurality of liquid crystal molecules, the liquid crystal molecules change the arrangement corresponding to the voltage difference generated between the pixel electrode and the common electrode, thereby providing from the backlight unit 200 The light is incident on the color filter substrate 330 according to the change in the molecular arrangement of the liquid crystal layer.

Such a structure and configuration of the display panel 300 is only an example, and the embodiments may be changed, added, or deleted within the scope of the spirit of the present invention.

The backlight unit 200 is adhesively fixed to the rear surface of the display panel 300, and for this purpose, an adhesive layer (not shown) may be further provided between the lower polarizer 310 and the backlight unit 200. have.

Hereinafter, a detailed structure of the backlight unit 200 will be described with reference to the drawings.

3 is a partial cross-sectional view showing the configuration of the backlight unit of FIG. 2, and FIG. 4 is a partial perspective view showing the arrangement of the light emitting unit of FIG. 3.

3 and 4, the backlight unit 200 includes a light emitting unit 210 arranged in an array form, a resin layer 230 provided to surround an upper portion of the light emitting unit 210, An optical sheet 250 attached to an upper surface of the resin layer 230, and a cover 290 on which the light emitting unit 210 is seated may be included. In addition, the light emitting unit 210 may be further provided with a reflective sheet 220 for reflecting light, and the resin layer 230 may be further provided with a groove 231 for diffusing and scattering light. .

The light emitting unit 210 may include a substrate 211, a plurality of light sources 212 disposed on the substrate 211, and a connector 213 for supplying power to the light source 212.

A plurality of light emitting units 210 may be arranged in the cover 290 in the form of an array. That is, the light emitting unit 210 may be disposed so that each side of the substrate 211 is in contact with each other to implement a rectangular backlight unit.

In this case, each of the light emitting units 210 may be independently controlled since the light emitting unit 210 is powered by the connector 213. That is, the light may be controlled so that only a part of the backlight unit 200 emits light. In other words, since the contrast between the bright area and the dark area in the display module 10 can be more surely obtained, a high contrast ratio can be realized.

The array structure of the light emitting unit 210 is just an example, and a plurality of light sources are disposed on one substrate, and a predetermined number of light sources are grouped into one group to control each group by dividing the driving region. The same effect can also be obtained. In the present embodiment, a structure in which the light emitting units 210 are arranged in an array form will be described as an example.

The substrate 211 may be formed in a square or rectangular shape, and a carbon nanotube electrode pattern (not shown) may be formed on an upper surface thereof. The carbon nanotube electrode pattern contacts the electrode formed on the light source 212 to electrically connect the connector 213 and the light source 212.

The substrate 211 may be a substrate formed of one of polyethylene terephthalate, glass, polycarbonate, and silicon, and may be formed in a flexible film form.

The light source 212 may be one of a light emitting diode (LED) chip or a light emitting diode package having at least one light emitting diode chip. In the present embodiment, a light emitting diode package is provided as the light source 212. In addition, such a light emitting diode package is divided into a top view method and a side view method according to a direction in which the light emitting surface is directed. In this embodiment, the top view in which the light emitting surface is formed upwards is top view. I'll take a look at the) package as an example.

The light source 212 includes a case 212b in which a light emitting diode chip is mounted, and a light emitting surface 212a emitting light emitted from the light emitting diode chip to the outside.

The LED chip may emit light of various colors, such as white, red, green, blue, white, and the like, and the color light may be emitted to the light emitting surface 212a. The light may be converted into white light through the dispensed fluorescent material and emitted outside the light source 212. In addition, a plurality of light emitting diode chips emitting light of different colors may be provided in the case 212b, and light emitted from each chip may be mixed to generate white light.

In addition, the directivity angle of the light emitted from the light source 212 may vary depending on the shape of the light emitting surface 212a and the arrangement of the light emitting diode chip. In this embodiment, a case in which the directivity angle of the light source 212 is about 120 degrees will be described as an example.

In addition, the case 212b may include a molding part (not shown) formed to seat the LED chip, and a lead frame (not shown) coupled to the molding part and fixed to the substrate.

On the other hand, the light sources 212 may be arranged to have a constant interval in each direction to implement a uniform brightness. That is, the light sources 212 may be disposed to have the same distance D1 in one direction, and may be disposed to have the same distance D3 in the other direction. In addition, since the light emitting units 210 are continuously arranged in an array form, in order to maintain the light sources of the adjacent substrates and the gaps D1 and D3, the distance between the light sources positioned at the edges and the edges of the substrate 211 ( D2 and D4 are formed to correspond to one half of the intervals D1 and D3, respectively.

When the light source 212 emits light in a circular shape, the light sources 212 are preferably arranged at equal intervals in each direction. In this case, the D1 and the D3 may be the same.

On the other hand, the upper surface of the substrate 211 may be further provided with a reflective sheet 220 for reflecting the light emitted from the light source (212). In particular, the reflective sheet 220 reflects the light totally reflected from the boundary of the groove 231 or the resin layer 230 so that the light emitted from the light source 212 can be spread more widely.

The reflective sheet 220 may have a hole in which the light source 212 may be inserted, and may be attached to the substrate 211. The reflective sheet 220 may be formed to correspond to the size of the light emitting unit 210 and may be attached to each light emitting unit, or may be formed to have a size corresponding to the entire backlight unit 200 so that one reflective sheet may be formed. The light emitting unit 210 may be attached to the array.

The reflective sheet 220 may include a white pigment such as titanium oxide dispersed in a sheet made of a synthetic resin, a metal deposition film laminated on a surface thereof, or a bubble dispersed to scatter light in a sheet made of a synthetic resin. In addition, silver (Ag) may be coated on the surface to increase the reflectance.

In addition, the reflective sheet 220 may be selectively provided, and may be attached to the lower surface of the substrate 211 when the substrate 211 is formed of a transparent material.

The resin layer 230 transmits the light emitted from the light source 212 and diffuses widely at the same time so that the backlight unit 200 has a uniform brightness. The resin layer 230 is formed to be in close contact with the upper surface of the substrate 211 (a reflective sheet when a reflective sheet is provided). The resin layer 230 is formed with a groove 231 recessed upwardly in the lower portion, and the light source 212 is formed to be inserted into the groove 231. In this case, the inner circumferential surface of the light source 212 and the groove 231 may be formed to be spaced a predetermined distance apart. That is, the resin layer 230 may be formed to be in close contact with the substrate 211 (or the reflective sheet) at a portion except for the periphery of the light source 212.

The resin layer 230 may be formed of a light transmissive material, and may be formed of a predetermined resin having a refractive index of about 1.4 to 1.6. For example, it may be formed of any one material selected from the group consisting of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene and polyepoxy, silicone, acrylic, and the like. However, the refractive index and the material of the resin layer 230 are not limited thereto, and any resin may be used as a material as long as light transmittance is satisfied. In addition, the resin layer 230 may be manufactured in the form of a flexible film.

In addition, the resin layer 230 may include a polymer resin having a predetermined adhesiveness to be in close contact with the light emitting unit 210. For example, unsaturated polyester, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, Hydroxypropyl methacrylate, hydroxy ethyl acrylate, acrylamide, metyrol acrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate, 2-ethylhexyl acrylate polymer or Acrylic type, urethane type, epoxy type, melamine type, etc., such as a copolymer or a terpolymer, can be used.

The resin layer 230 may be separately manufactured and adhered to the light emitting unit 210.

As the thickness of the resin layer 230 increases, light emitted from the light source 212 may be spread more widely, so that light having a more uniform brightness may be provided to the display panel 300. However, when the thickness of the resin layer 230 is increased, the thickness of the display module 20 is increased to increase the thickness of the display device 1 and the amount of light absorbed by the resin layer 230 is increased. As a result, the luminance of light provided to the display panel 300 may be reduced as a whole. Therefore, the thickness of the resin layer 230 may be formed to a thickness of 0.1 to 4.5mm so as to have a uniform brightness without hot spots and the like without significantly reducing the brightness.

On the other hand, a groove 231 for refracting and scattering light emitted from the light source 212 is formed below the resin layer 230. The groove 231 may be formed by engraving the resin layer 230, and air is filled therein.

The groove 231 is formed to correspond to the position of the light source 212 so that the light source 212 can be fitted. As described above, the inner circumferential surface of the groove 231 may be formed to be spaced apart from the light source 212, in particular, the light emitting surface 212a by a predetermined distance. Therefore, light emitted from the light emitting surface 212a may be refracted as it is incident on the resin layer 230 after passing through air.

In addition, the groove 231 is formed with a scattering unit 231b to be described later so that the light emitted from the light source 212 can be scattered and diffused.

Light emitted through the resin layer 230 is incident on the display panel 300 via the optical sheet 250. Since most of the light emitted from the resin layer 230 is light refracted in the groove 230, the light is incident on the optical sheet 250 at a predetermined angle. However, since the light incident on the display panel 300 is vertical when the light efficiency is high, the optical sheet 250 has the light emitted from the resin layer 230 perpendicular to the display panel 300. To be incident.

The optical sheet 250 may include a diffusion sheet, a prism sheet, and a protective sheet. At this time, the sheets are provided in a state of being bonded or adhered to each other without being spaced apart from each other. Therefore, the thickness of the optical sheet 250 can be minimized.

The diffusion sheet disperses the light incident through the resin layer 230 to prevent the light from being partially concentrated and makes the luminance uniform. The prism sheet collects light whose brightness has fallen sharply through the diffusion sheet so that light may be incident vertically toward the display panel 300. The protective sheet diffuses the light passing through the prism sheet to the entire area of the display panel 300 and prevents the prism sheet from being damaged. The configuration of such an optical sheet is only one example, and it will be possible to add, change, or delete the embodiments within the scope of the spirit of the present invention. For example, at least one or more of the diffusion sheet, the prism sheet, and the protective sheet may be removed, and various functional layers may be further added.

Meanwhile, the bottom surface of the optical sheet 250 is in close contact with the resin layer 230, and the top surface is in close contact with the bottom surface of the display panel 300.

The cover 290 supports the backlight unit 200 and the display panel 300 and is formed to allow the backlight unit 200 to be seated. In addition, the cover 290 is formed with a connection hole 291 at a point corresponding to the position of the connector 213. The connection hole 291 is formed to have a larger size than the connector 213 so that a predetermined jack can be smoothly inserted into the connector 213. Thus, the connector 213 is exposed to the rear of the cover 290, the operator can work conveniently.

In addition, the connection hole 291 is formed, and the connector 213 formed to protrude on the rear surface of the substrate 211 is fitted into the connection hole 291, so that the substrate 211 is covered by the cover 290. ) Can be completely adhered to. Therefore, since heat generated from the substrate 211 can be smoothly transferred to the cover 291 by conduction, heat dissipation performance of the display module 10 may be improved.

As such, the cover 290, the backlight unit 200, and the display panel 300 are configured to be in close contact with each other, so that the thickness of the display module 10 may be minimized.

In particular, the groove 231 is formed in the resin layer 230 of the backlight unit 200, so that the light emitted from the light source 212 can be effectively dispersed to the surroundings. Can be removed.

Hereinafter, with reference to the drawings, it will be described in detail the light is diffused by the groove 231.

FIG. 5 is a view illustrating a light diffused in the resin layer of FIG. 3.

Referring to FIG. 5, light is emitted from the light source 212 toward the upper side and a predetermined angle side. As described above, the angle of the light irradiated from the light source 212 may be changed by the arrangement of the light emitting surface 212a and the light emitting diode.

Light emitted from the light source 212 is refracted at the boundary of the groove 231 and diffused to the surroundings. In detail, air having a refractive index of 1 is filled in the groove 231, and the resin layer 230 has a refractive index of greater than one.

Light passing through two media having different refractive indices is refracted according to the following equation.

Equation

Since the refractive index of the resin layer 230 is larger than that of air, the refractive angle is larger than the incident angle at the boundary of the groove 231. Therefore, a part of the light passing through the boundary of the groove 231 is refracted and emitted toward the side of the light source 212. That is, light may be diffused.

In addition, when the incident angle of light is larger than the critical angle, the light does not cross the boundary and is totally reflected. That is, when light emitted from the light source 212 is incident on the boundary of the groove 231 at an angle greater than the critical angle of the resin layer 230, the light is totally reflected at the boundary of the groove 231, and thus the number of light is emitted again. Proceed to strata 230. The light propagated to the resin layer 230 may be reflected by the reflective sheet 220, may be refracted through the boundary of the groove 231, or may be totally reflected again. As such, the light totally reflected at the boundary of the groove 231 may travel laterally than the original path, so that the light emitted from the light source 212 may be more diffused.

In this case, the width of the groove 231 may be wider than the width of the light emitting surface 212a. Accordingly, light emitted from the edge as well as the center of the light emitting surface 212a may be refracted and diffused in the groove 231.

On the other hand, the groove 231 is a ceiling portion 231a which is formed in parallel with the light emitting surface 212a, the scattering portion 231b is formed on the lower side of the ceiling portion 231a and scattering pattern for scattering light is formed, and A side portion 231c forming a side surface of the groove 231 is included.

The scattering portion 231b is provided between the ceiling portion 231a and the side surface portion 231c, and is formed in a shape that protrudes sharply toward the center of the groove 231. A scratch (not shown) may be formed in the scattering unit 231b in a vertical or horizontal direction with a traveling direction of the incident light so that light emitted from the light source 212 may be scattered. The scratches may be formed in discrete shapes and arrangements. The scratch pattern as described above is just an example, and various known techniques for scattering such as sand grains of fine particles may be applied to the scattering unit 231b.

In particular, the scattering part 231b may be formed in a band shape along the circumference of the groove 231, and the diameter of the band shape may be smaller than the width of the light emitting surface 212a. Therefore, since light emitted vertically upward from the light emitting surface 212a may be scattered while passing through the scattering unit 231b, the light diffusion effect may be maximized.

The side portion 231c may be formed in such a manner that an absolute value of the slope of the tangent line increases toward the edge.

Since the light scattered from the scattering unit 231b proceeds in various unspecified directions, light emitted from the light source 212 may be diffused laterally. As described above, light refraction may also occur at the boundary of the groove 231. That is, light scattering and refraction occur simultaneously. Therefore, even if the resin layer 230 surrounds the light source 212, the optical sheet 250 is in close contact with the resin layer 230, and the display panel 300 is in close contact with the optical sheet 250. Hot spots do not occur, and the backlight unit 200 may exhibit uniform luminance as a whole.

As described above, light that is refracted and scattered while passing through the resin layer 230 passes through the optical sheet 250 and is diffused and condensed, and is emitted to the display module 300.

Since light emitted from the light source 212 is refracted or scattered laterally while passing through the groove 231, the luminance at a point corresponding to the position of the light source 212 is relatively low, and the periphery of the light source 212 is reduced. The brightness of is increased. In addition, since the light diffused from the adjacent light source is incident together at a point where the distance from one light source may be lowered, the luminance may be maintained at a predetermined level. Therefore, the hot spot region disappears from the backlight unit 200 and may have a uniform luminance as a whole.

In addition, since the light emitted from one light source 212 may be widely spread by the resin layer 230, the number of light sources per unit area of the backlight unit 200 may be reduced. Therefore, manufacturing cost can be reduced.

Hereinafter, a backlight unit according to a second embodiment of the present invention will be described with reference to the drawings. However, since the second embodiment has a difference in the shape of the grooves compared with the first embodiment, the differences are mainly described, and the same reference numerals and descriptions of the first embodiment are used for the same parts.

FIG. 6 is a view illustrating a light diffused in a resin layer of a backlight unit according to a second embodiment of the present invention.

Referring to FIG. 6, the center portion 233a of the ceiling portion 233b of the groove 233 of the backlight unit according to the second embodiment of the present invention may be formed to protrude downward, and closer to the center thereof. It may be formed so that the absolute value of the slope of the tangent line is rounded. That is, the ceiling portion 233b of the groove 233 may be formed in a bat-wing shape. The groove 233 includes a scattering portion 233c and a side portion 233d as in the first embodiment.

In this case, a predetermined scattering pattern may be formed at both edges of the central portion 233a and the ceiling portion 233b like the scattering portion 233c. Therefore, light emitted from the light source 212 may be scattered at both edges of the central portion 233a and the ceiling portion 233b. In addition, light scattered by the scattering unit 233c may be scattered again at both edges of the central portion 233a and the ceiling portion 233b. That is, since light may be scattered in duplicate, the light diffusion effect may be maximized. In addition, since the light emitted from the center of the light emitting surface 212b having the strongest light is refracted or scattered, it is possible to prevent the occurrence of hot spots.

In addition, since the ceiling portion 233b is formed in a bat-wing shape, light refraction may also occur in various ways. Therefore, the light can be diffused more smoothly.

Hereinafter, a backlight unit according to a third embodiment of the present invention will be described with reference to the drawings. However, since the third embodiment has a difference in that a diffusion plate is provided in comparison with the first embodiment, the difference is mainly described, and the same reference numerals are used for description of the first embodiment.

7 is a partial cross-sectional view of the backlight unit according to the third embodiment of the present invention.

Referring to FIG. 7, a diffusion plate 241 for diffusing light passing through the resin layer 230 may be further provided on the resin layer 230 of the backlight unit according to the third exemplary embodiment of the present invention. have. In this case, the diffusion plate 241 may be attached to the bottom surface of the optical sheet 250 and the top surface of the resin layer 230. In addition, the diffusion plate 241 may be provided between the optical sheet 250 and the display panel 300.

In addition, a groove (not shown) in which light may be refracted may be further formed in the diffusion plate 241. In this case, the grooves formed in the diffusion plate 241 may be formed to intersect with the grooves 231 of the resin layer 230 to further increase the diffusion effect due to refraction. In this case, the diffusion plate 241 may be formed of a material having a lower refractive index than the resin layer 230 so that the light is further refracted.

The diffusion plate 241 may provide light having a more uniform brightness by diffusing light refracted in various patterns in the resin layer 230 and supplying the light to the optical sheet 250.

Hereinafter, a backlight unit according to a fourth embodiment of the present invention will be described with reference to the drawings. However, since the fourth embodiment has a difference in that a light shielding sheet is provided as compared with the first embodiment, the description will be mainly focused on the difference, and the description and reference numerals of the first embodiment are used for the same parts.

8 is a partial cross-sectional view of the backlight unit according to the fourth embodiment of the present invention.

Referring to FIG. 8, the backlight unit according to the fourth exemplary embodiment of the present invention is provided with a light blocking sheet 271 that can block a part of the light emitted from the light source 212.

The light blocking sheet 271 may be formed of a transparent material, and may be disposed between the resin layer 230 and the optical sheet 250. In this case, each surface of the light blocking sheet 271 may be attached to the resin layer 230 and the optical sheet 250.

A light blocking pattern 271a is formed on the light blocking sheet 271 so as to correspond to the position of the light source 212. The light shielding pattern 271a may be printed on the light shielding sheet 271 directly above the light emitting surface 212a, and its size may be adjusted according to the intensity of light emitted from the light source 212. The light blocking pattern 271a may be formed of titanium dioxide (TiO 2). In this case, a part of the light incident from the light source 212 may be reflected downward, and the other part may be transmitted.

The light blocking pattern 271a is formed to have a predetermined opacity to reduce the luminance of light emitted from the light source 212. In detail, the light emitted from the light source 212 is refracted by the groove 231 or scattered by the scattering unit 231b, but the upper portion of the light emitting surface 212a has a higher luminance than the surroundings. May appear. Therefore, when the light shielding pattern 271a having a predetermined opacity is formed directly above the light emitting surface 212a, the luminance may be lowered, and the backlight unit 200 may be implemented to have a uniform luminance as a whole. The opacity of the light blocking pattern 271a is adjusted according to the light intensity of the light source 212.

In addition, the light blocking pattern 271a may be formed to correspond to the shape of the groove 231 or the scattering portion 231b. For example, when the cross-sections of the grooves 231 and the scattering portions 231b are formed in a circular shape, the light shielding pattern 271a may be formed in a circular shape and printed so that the opacity of the edge portion is larger or smaller than the surroundings. have.

The light blocking sheet 271 may be disposed between the optical sheet 250 and the display panel 300. In this case, part of the diffused and condensed light may not be transmitted while passing through the optical sheet 250, and thus brightness may be directly adjusted.

In addition, the light blocking sheet 271 may be disposed between the diffusion sheet and the prism sheet or between the prism sheet and the protective sheet.

The light shielding pattern 271a may not be formed on the light shielding sheet 271 provided separately, but may be directly printed on the bottom or top surface of the optical sheet 500. In this case, the light quality may be further improved without changing the thickness of the backlight unit 200.

Hereinafter, a backlight unit according to a fifth embodiment of the present invention will be described with reference to the drawings. However, the fifth embodiment has a difference in that bubbles are formed in the resin layer compared with the first embodiment. Therefore, the fifth embodiment will be described mainly for differences, and the description and reference numerals of the first embodiment will be used for the same parts.

9 is a partial cross-sectional view of the backlight unit according to the fifth embodiment of the present invention.

Referring to FIG. 9, the resin layer 230 of the backlight unit according to the fifth embodiment of the present invention includes bubbles 237 having various sizes. Since the bubble 237 is filled with air, light is refracted when the light proceeds from the resin layer 230 to the bubble 237. That is, light emitted from the light source 212 by the bubble 237 may be refracted in various patterns while passing through the resin layer 230, thereby maximizing the light diffusion effect.

At this time, the bubble 237 may be formed through the thermal decomposition of a predetermined blowing agent, the diameter of the bubble 237 may be 1㎛ to 20㎛.

If the diameter of the bubble 237 is small, the number of the bubbles 237 is increased, so that the refractive effect of the resin layer 230 may be improved. However, if the diameter of the bubble 237 is too small, the light source 212. Interference of light emitted from Therefore, the diameter of the bubble 237 is 1㎛ or more, so that the refraction effect can be improved as long as the interference of light does not occur.

In addition, when the diameter of the bubble 237 is large, the number of bubbles 237 is reduced, so that light is refracted in various patterns sufficiently and does not diffuse while passing through the resin layer 230. In this case, when the thickness of the resin layer 230 is increased in order to secure the number of bubbles 237, there is a problem that the thickness of the backlight unit 200 becomes thick. Therefore, the diameter of the bubble 237 is formed to be 20㎛ or less, so that the light emitted from the light source 212 is refracted or diffused by a predetermined level or more to be incident to the optical sheet 500 and at the same time the backlight The unit 200 can be thinned.

Hereinafter, a backlight unit according to a sixth embodiment of the present invention will be described with reference to the drawings. However, since the sixth embodiment differs in that scattering particles are formed in the resin layer compared with the first embodiment, the differences will be mainly described, and the same reference numerals and reference numerals are used for the same parts. .

10 is a partial cross-sectional view of the backlight unit according to the sixth embodiment of the present invention.

Referring to FIG. 10, the resin layer 230 of the backlight unit according to the sixth exemplary embodiment includes scattering particles 238 that scatter or refract light. Therefore, the light emitted from the light source 212 can be spread more widely.

The scattering particles 238 may be formed of a material having a refractive index different from that of the resin layer 230 in order to scatter or refract light emitted from the light source 212. For example, the scattering particles 231 may be composed of polymethyl methacrylate / styrene copolymer (MS), polymethyl methacrylate, polystyrene, silicon, titanium dioxide (TiO 2), silicon dioxide (SiO 2), or the like. It may be configured by combining the above materials.

In addition, the scattering particles 238 may be formed of a material having a lower refractive index than the material constituting the resin layer 230.

The resin layer 230 may be cured by mixing the scattering particles 238 with a resin in a liquid or gel form, and then printing the grooves 231 by engraving the grooves 231 and then attaching the light emitting units to the light emitting unit 210. have.

Hereinafter, a backlight unit according to a seventh embodiment of the present invention will be described with reference to the drawings. However, since the seventh embodiment differs in that the heat dissipation hole and the heat dissipation film are provided in comparison with the first embodiment, the difference is mainly described, and the same reference numerals and reference numerals are used for the same parts. .

11 is a partial cross-sectional view of a backlight unit according to a seventh embodiment of the present invention.

Referring to FIG. 11, a heat dissipation hole 214 for dissipating heat is formed in the substrate 211 of the backlight unit according to the seventh embodiment of the present invention. The heat dissipation hole 214 is formed so that the heat generated from the light source 212 can be smoothly discharged to the rear side of the cover 100 may be formed to correspond to the position of the lead electrode of the LED chip. .

In addition, a heat radiation film 215 may be provided on the rear surface of the substrate 211 to improve heat radiation efficiency. The heat dissipation film 215 may be attached to each of the light emitting units 210, and the heat dissipation film 215 may be attached to the cover 210 first, and then the light emitting unit 210 may be attached.

On the other hand, the connection hole 292 formed in the cover 100 may be formed to increase the contact area with the air in order to increase the heat transfer efficiency by the convection. For example, the connection hole 292 may be formed to a size such that a position corresponding to the light source 212 where the heat is concentrated may be exposed to air.

In this case, the heat dissipation film 215 may be a carbon nanotube (CNT) heat dissipation film, and the heat dissipation hole 214 may be filled with a thermally conductive filler.

By such a structure, even when the light source 212 is wrapped in the resin layer 230, smooth heat dissipation can be achieved from the backlight unit 200.

FIG. 12 is a view illustrating a light diffused in a resin layer of a backlight unit according to an eighth embodiment of the present invention.

Referring to FIG. 12, a backlight unit according to an eighth embodiment of the present invention includes a light source 212 ′ configured as a side view type light emitting diode package that emits light laterally. The light emitting surface of the light source 212 ′ is formed on the side of the light source 212 ′, and the light sources 212 ′ provided to the backlight unit 200 may be aligned in the same direction.

Since the light source 212 ′ emits light toward the side and the emitted light is refracted to the side while passing through the groove 231, the light diffusion effect may be maximized. In addition, a hot spot phenomenon in which light is concentrated may be less observed than when a top view type LED package is provided. In addition, since the thickness of the resin layer 230 for diffusing light can be reduced compared to the case where a top view type LED package is provided, the display device 1 can be made thinner.

Light emitted from the light source 212 ′ may pass through the groove 231 to the groove surrounding the adjacent light source. The light propagated to the grooves surrounding the adjacent light sources is refracted or diffused while passing through the grooves to supply light to the rear of the adjacent light sources, that is, the light emitted from the adjacent light sources is not directly touched, so that the entire backlight unit 200 is uniform. It can be made to have one brightness.

In addition, the light source 212 ′ may be arranged to emit light in a direction in which adjacent columns or adjacent rows cross each other. For example, the n rows of light sources emit light toward the right side, and the n + 1 rows of light sources can be arranged to emit light toward the left side.

In addition, the top view type LED package and the side view type LED package may be mixed with each other.

13 is a cross-sectional view schematically illustrating a configuration of a display apparatus according to an embodiment of the present invention.

Referring to FIG. 13, the backlight unit 200 and the display panel 300 are provided in close contact with each other. As described above, an adhesive layer may be further provided between the backlight unit 200 and the display panel 300.

The backlight unit 200 may be attached to a lower side of the display panel 300, in detail, a lower side of the lower polarizer 310. The surface contacting the display panel 300 may be the resin layer 230 or the optical sheet 250.

The display module 20 including the backlight unit 200 and the display panel 300 may be attached and fixed to the front cover 11, and the back cover 12 may be attached to the front cover 11. ) May be fixed to a fastening member (not shown) such as a bolt.

In addition, the display apparatus 1 includes a power supply unit 400 for supplying power to the backlight unit 200 and the display panel 300, and the backlight unit 200 and the display panel 300. The control unit 500 for controlling the driving of a. For example, the controller 500 may be a timing controller.

The timing controller controls the driving timing of the display panel 300. In particular, the timing controller generates a signal for controlling the driving timing of the data driver, the gamma voltage generator, and the gate driver of the display panel 300. The display panel 300 may be transferred to the display panel 300. In addition, the timing controller may transmit a signal for controlling the driving timing of the light emitting unit 210 to the backlight unit 200.

The power supply unit 400 and the control unit 500 may be electrically connected to the connector 213 to supply power to the backlight unit 200 or to control the backlight unit 200.

Meanwhile, the power supply unit 400 and the control unit 500 are mounted to the back cover 12. In detail, the backlight unit 200 may be provided in the form of a thin film and is adhesively fixed to the display panel 300. The backlight unit 200 may be spaced apart from the display panel 300. In order to prevent such a problem, at least one of the power supply unit 400 and the control unit 500 is mounted to the back cover 12 for stable and secure fixing. Preferably, both the power supply unit 400 and the control unit 500 may be mounted to the back cover 12.

The back cover 12 may be formed to be spaced apart from the rear surface of the backlight unit 200 by a predetermined distance, and the power supply unit 400 and the control unit 500 may include the backlight unit 200 and the back cover. It may be provided in the space between (12). In this case, since the distance between the power supply unit 400 and the connector 213 exposed on the back surface of the backlight unit 200 from the control unit 500 may be minimized, the arrangement of the conductors may be simplified. There is an advantage.

The scope of the present invention is not limited to the above-described embodiments, and the embodiments may be changed, added, or deleted within the scope of the spirit of the present invention.

1 is an exploded perspective view schematically showing the configuration of a display device including a backlight unit according to a first embodiment of the present invention.

2 is a partial cross-sectional view of the display module of FIG.

3 is a partial cross-sectional view showing the configuration of the backlight unit of FIG.

4 is a partial perspective view showing the arrangement of the light emitting unit of FIG. 3.

5 is a view showing a light diffusion in the resin layer of FIG.

6 is a view showing a light diffusion in the resin layer of the backlight unit according to the second embodiment of the present invention.

7 is a partial sectional view of a backlight unit according to a third embodiment of the present invention;

8 is a partial cross-sectional view of a backlight unit according to a fourth embodiment of the present invention.

9 is a partial sectional view of a backlight unit according to a fifth embodiment of the present invention;

10 is a partial cross-sectional view of a backlight unit according to a sixth embodiment of the present invention.

11 is a partial cross-sectional view of a backlight unit according to a seventh embodiment of the present invention.

12 is a view showing a light diffusion in the resin layer of the backlight unit according to the eighth embodiment of the present invention.

13 is a cross-sectional view schematically showing the configuration of a display device according to an embodiment of the present invention.

Claims (19)

Board; A plurality of light sources disposed on the substrate; And It is formed recessed from below, and includes a resin layer is formed a groove into which the light source can be inserted, The inner circumferential surface of the groove is formed to be spaced apart from the light emitting surface of the light source, The scattering unit for scattering the light emitted from the light source is formed on the inner peripheral surface of the groove. The method of claim 1, The resin layer is in close contact with the upper surface of the substrate. The method of claim 1, And a reflective sheet is attached to the substrate. The method of claim 1, The upper portion of the groove is formed in a bat-wing shape, The scattering unit is a backlight unit, characterized in that formed on the lower side of the batwing shape. The method of claim 1, The scattering portion is formed in a band shape along the circumference of the groove, And a width of the scattering portion is smaller than a width of the light emitting surface. The method of claim 1, An optical sheet is further attached to the upper surface of the resin layer. The method of claim 1, And the light sources are arranged at equal intervals. The method of claim 1, The light source may be any one of a light emitting diode chip or a light emitting diode package having at least one light emitting diode chip. The method of claim 8, And said light source emits light upwards. The method of claim 1, The refractive index of the resin layer is a backlight unit, characterized in that 1.4. The method of claim 1, And a connector for supplying power to the light source is formed on a rear surface of the substrate. The method of claim 11, The cover is in close contact with the back of the substrate to form a back of the backlight unit, And a connection hole is formed in the cover to expose the connector. The method of claim 1, And a heat dissipation film is provided on the back of the substrate. The method of claim 1, The resin unit is a backlight unit, characterized in that a plurality of scattering units or a plurality of bubbles of various sizes are formed. The method of claim 1, The substrate is arranged in a plurality of arrays, Back light unit, characterized in that each substrate is controlled independently. A display module comprising a backlight unit of any one of claims 1 to 15 and a display panel disposed in front of the backlight unit; A front cover to which the display module is fixed; And A back cover covering a rear surface of the display module is included; The backlight unit is in close contact with the display panel. The method of claim 16, The display panel, A thin film transistor substrate and a color filter substrate; A liquid crystal layer provided between the thin film transistor substrate and the color filter substrate; An upper polarizer provided on the color filter substrate; And A lower polarizer provided under the thin film transistor substrate, And the backlight unit is in close contact with the lower polarizer. The method of claim 16, A power supply unit supplying power to the display module; And A control unit for controlling the driving of the display module is further included. At least one of the power supply unit and the control unit is fixed to the back cover. The method of claim 18, And at least one of the power supply unit and the control unit is disposed in a space between a rear surface of the display module and the back cover.

Images