KR20110064433A - Backlight unit and display apparatus including the same - Google Patents

Abstract

PURPOSE: A backlight unit and display device including the same are provided to improve a heat performance and prevents an optical sheet by the heat generated from a light source. CONSTITUTION: A backlight unit(200) includes a substrate, a plurality of light source(212), a heat absorbing layer(230), a case, and lead frames. The plurality of light source is arranged on one side of the substrate. A heat absorbing layer is formed to cover the light source. The optical sheet is closely attached to the heat absorbing layer. The case has a light emitting diode chip to the light source and a contact surface of the heat absorbing layer and the optical sheet is separately formed from the light source. The anode lead frame and cathode lead frame includes a connecting unit.

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).

An object of the present invention is to provide an ultra-thin backlight unit and a display device including the same.

In addition, an object of the present invention is to provide a backlight unit in which deformation of an optical sheet due to heat generated from a light source is prevented and a display device including the same.

In addition, an object of the present invention is to provide a backlight unit having improved heat generation performance and a display device including the same.

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 one side of the substrate; A heat absorption layer formed to surround the light source; And an optical sheet in close contact with the heat absorbing layer, wherein a contact surface of the heat absorbing layer and the optical sheet is formed to be spaced apart from the light source, and a light emitting diode chip is mounted on the light source. An anode lead frame and a cathode lead frame connected to the light emitting diode chip, the contact part being exposed to the outside of the case and contacting an electrode of the substrate, wherein at least a part of the contact part is directly below the light emitting diode chip. It is characterized by extending to form.

In another aspect, a display device according to an embodiment of the present invention includes a substrate; A plurality of light sources disposed on one side of the substrate; A heat absorption layer formed to surround the light source; And an optical sheet in close contact with the heat absorbing layer, wherein a contact surface of the heat absorbing layer and the optical sheet is formed to be spaced apart from the light source, and a light emitting diode chip is mounted on the light source. An anode lead frame and a cathode lead frame connected to the light emitting diode chip, the contact part being exposed to the outside of the case and contacting an electrode of the substrate, wherein at least a part of the contact part is directly below the light emitting diode chip. 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, since the heat emitted from the light source is absorbed by the heat absorbing layer and then transferred to the display panel, deformation of the optical sheet is prevented.

In addition, there is an advantage that the heat generation performance is improved by improving the structure of the LED package.

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, FIG. 4 is a plan view showing the arrangement of the light emitting unit of FIG. 3, and FIG. 5 is an exploded perspective view showing the structure of the light source of FIG. 3.

3 to 5, the backlight unit 200 includes a light emitting unit 210 that emits light, a heat absorbing layer 230 provided to cover an upper portion of the light emitting unit 210, and the heat absorbing layer ( An optical sheet 250 attached to an upper surface of the 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.

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 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 lead frame of 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 provided as a light emitting diode package having at least one light emitting diode chip (LED). 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 light emitting surface is formed in a 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 212c is mounted, and a light emitting surface 212a for emitting light emitted from the light emitting diode chip to the outside.

In detail, the case 212b of the light source 212 may include a front case 212b 'including the light emitting surface 212a and a rear case 212b ″ on which the light emitting diode chip 212c is mounted. have.

Here, when the light source 212 is viewed from the light emitting surface 212a side, the axis of symmetry in the long direction is called the long axis, and the axis of symmetry in the short direction is called the short axis.

The rear case 212b ″ is provided with a positive lead frame 212d and a negative lead frame 212e spaced apart from each other, and the LED chip 212c includes the positive lead frame 212d and the negative lead frame ( 212e. The light emitting diode chip 212c may be attached to any one of the lead frames 212d and 212e and then wire bonded or flip chip bonding. In this embodiment, the light emitting diode chip 212c is attached to the anode lead frame 212d by way of example.

Further, on the lead frames 212d and 212e, not only the light emitting diode chip 212c but also a protection element such as a zener diode for protecting the light emitting diode chip 212c from electrostatic discharge (ESD) It can also be mounted together.

The anode lead frame 212d is disposed in the case 212b and divided into a portion 212d 'on which the light emitting diode chip 212c is seated and a portion 212d ″ exposed to the outside of the light source 212. In addition, the negative lead frame 212e may also be divided into a portion 212e 'disposed inside the case 212b and a portion 212e ″ exposed to the outside of the light source 212. The exposed portions 212d ″ and 212e ″ may be formed by bending and cutting the lead frame.

The exposed portions 212d ″ and 212e ″ may form a part of the bottom surface of the light source 212 and may contact an electrode formed on the substrate 211. Accordingly, the exposed portions 212d ″ and 212e ″ may be referred to as contacts. The electrode formed on the substrate 211 is formed to correspond to the size and shape of the exposed portions 212d ″ and 212e ″.

On the other hand, the thermal resistance is proportional to the length of the medium through which heat is transferred and inversely proportional to the area. That is, the longer the path of heat transfer, the greater the heat resistance, so that the heat is not transferred. The smaller the contact area, the greater the heat resistance, and the heat is not transferred.

Heat emitted from the light emitting diode chip 212c is transferred to the lead frames 212d and 212e through a wire or the like. The heat transferred to the lead frames 212d and 212e is transferred to the electrodes of the substrate 211. Therefore, the path through which heat is transferred to the electrodes of the substrate 211 through the lead frames 212d and 212e is short, and the larger the contact area with the electrode is, the smaller the thermal resistance is, so that heat can be transferred well.

In the lead frames 212d and 212e of the light source 212 according to the embodiment of the present invention, the major axis lengths of the contact portions 212d ″ and 212e ″ are not less than 1/2 of the major axis lengths of the case 212b. It may be formed to.

In particular, the anode lead frame 212d to which the light emitting diode chip 212c is bonded is formed to extend directly under the light emitting diode chip 212c to form the contact portion 212d ″, so that heat is transmitted. In other words, at least a portion of the contact portion 212d ″ is positioned directly below the light emitting diode chip 212c. Since the length of the path through which heat is transferred is shortened, the thermal resistance of the lead frame 212d may be reduced, so that heat may be transferred well.

In addition, the widths of the contact portions 212d ″ and 212e ″ may be formed to be 1/2 or more of the width of the bottom surface of the case 212b. Therefore, since the area where the heat transfer is made is widened, the heat resistance can be reduced and heat can be transferred well.

The width of the substrate 211 may also be adjusted to correspond to the size and width of the contact portions 212d ″ and 212e ″.

As described above, when the lead frames 212d and 212e are formed, only a part of the lead frame can improve the light emission performance compared to the conventional package structure in which both ends of the LED package are exposed.

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.

On the other hand, the light sources 212 may be arranged to have a constant interval in each direction to implement a uniform brightness.

A reflective sheet 220 may be further provided on the upper surface of the substrate 211 to reflect light emitted from the light source 212. In particular, the reflective sheet 220 reflects the light totally reflected from the boundary of the heat absorbing 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 heat absorbing layer 230 absorbs heat emitted from the light source 212. In detail, the heat emitted from the light source 212 is prevented from being directly transmitted to the optical sheet 250 and the display panel 300.

In addition, the heat absorbing layer 230 transmits the light emitted from the light source 212 and diffuses widely so that the backlight unit 200 has a uniform brightness. The heat absorbing layer 230 may be formed to surround the light source 212, and may be formed to be in close contact with at least the light emitting surface 212a. In addition, the heat absorption layer 230 may be formed to completely surround the light source 212 and to be in close contact with the reflective sheet 220.

The heat absorbing layer 230 is formed of a light transmissive material, and is formed such that a boundary of the heat absorbing layer 230 is spaced a predetermined distance from an upper end of the light source 212. In other words, the boundary between the heat absorbing layer 230 and the optical sheet 250 is spaced apart from the light source 212.

In addition, the heat absorbing layer 230 may be formed of a predetermined material 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, ceramic, and the like. However, the refractive index and the material of the heat absorbing layer 230 are not limited thereto, and any resin may be used as the material as long as the light transmittance is satisfied. In addition, the heat absorption layer 230 may be manufactured in the form of a flexible film.

In addition, the heat absorbing layer 230 may include a polymer resin having a predetermined adhesiveness so as to be tightly adhered to 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 heat absorbing layer 230 may be formed by applying a liquid or a gel-like resin to the upper portion of the light emitting unit 210 and curing it, or may be separately manufactured and adhered to the light emitting unit 210.

The heat absorbing layer 230 absorbs heat emitted from the light source 212. The heat absorbing layer 230 may be provided to completely surround the light source 212 to absorb heat by conduction. Since the heat emitted from the light source 212 is absorbed by the heat absorbing layer 230 and then transferred to the optical sheet 250 and the display panel 300, the deformation caused by the temperature rise of the optical sheet 250 It can prevent. In addition, since the temperature rise of the display panel 300 can be prevented, performance degradation, deformation, and product failure due to heat can be prevented.

As the thickness of the heat absorbing 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, if the thickness of the heat absorbing 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 heat absorbing 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 heat absorbing layer 230 may be adjusted to have a uniform brightness without hot spots and the like without significantly reducing the brightness.

In consideration of the heat generation performance and the brightness problem as described above, the heat absorption layer 230 may be formed to a thickness of 1mm to 4.5mm. In detail, when the heat absorbing layer 230 is provided to be 1 mm or less, since the heat emitted from the light source 212 is not sufficiently absorbed, the optical sheet 250 may be deformed, and there is a risk that hot spots are generated. . In addition, when the heat absorbing layer 230 is provided in more than 4.5mm, it is difficult to manufacture the backlight unit 200 in the form of a film due to the thickness of the heat absorbing layer 230, the backlight unit 200 ), There is a problem that the overall brightness of h) decreases.

Heat absorbed by the heat absorbing layer 230 may be transferred to the substrate 211 and the cover 290 to be discharged to the rear of the backlight unit 200.

Light emitted through the heat absorbing layer 230 is incident on the display panel 300 via the optical sheet 250. Since most of the light emitted from the heat absorbing 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 heat absorbing 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 heat absorbing 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, it will be possible to add, change, delete the embodiment 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 heat absorbing 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, since the heat emitted from the light source 212 by the heat absorbing layer 230 is prevented from being directly transmitted to the optical sheet 250 and the display panel 300, the performance of the display device 1 is lowered Can be prevented.

In addition, heat is dissipated to the heat absorbing layer 230 and at the same time, the structure of the lead frames 212d and 212e of the light source 212 is improved, and thus, the back of the backlight unit 200 through the substrate 211. Since heat can be effectively transmitted, heat dissipation performance can be maximized.

In addition, since the light emitted from the light source 212 in the heat absorbing layer 230 is effectively dispersed to the surroundings, it is possible to prevent the occurrence of hot spots and maintain uniform luminance as a whole.

6a and 6b are views showing the heat absorption effect by the heat absorption layer.

FIG. 6A is a diagram illustrating a result of measuring a temperature of a backlight unit in a state in which a heat absorbing layer is not provided, and FIG. 6B is a result of measuring a temperature of the backlight unit 200 provided with the heat absorbing layer 230. Figure showing.

6A shows that the thickness of the light source 212 having an output of 2 mm and the thickness of the substrate 211 is 1.2 mm, the thickness of the optical sheet 250 is 2 mm, and the thickness of the liquid crystal panel 300. It is an experimental result after setting to 2 mm, and FIG. 6B is an experimental result after setting the thickness of the heat absorption layer 230 to 3 mm under the same conditions as FIG. 6A.

Referring to FIG. 6A, the average temperature of the substrate 211 is about 87.5 ° C, the average temperature of the optical sheet 250 is about 87.9 ° C, and the average temperature of the display panel 300 is about 80 ° C. Looking at the portion of the light emitting unit 210, since the temperature around the light source 212 is higher, it can be seen that the heat generating subject is the light source 212.

6B, the average temperature of the substrate 211 was about 88.7 ° C., the average temperature of the optical sheet 250 was about 82 ° C., and the average temperature of the display panel 300 was about 75 ° C. FIG. That is, since the heat absorbing layer 230 is provided, it can be seen that the average temperature of the optical sheet 250 and the display panel 300 is lowered by about 5 ° C. or more.

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 structure of the light source 212 and the shape of the substrate 211 as compared with the first embodiment, the differences will be mainly described, and the same parts will be described in the first embodiment. And reference numerals are used.

FIG. 7 is a partial cross-sectional view of the backlight unit according to the second exemplary embodiment of the present invention, and FIG. 8 is a plan view illustrating an arrangement of the light emitting unit of FIG. 7.

7 and 8, the lead frame 212g of the light source 212 extends to the rear surface of the case 212b. That is, the lead frame 212g may be exposed to the bottom surface and the bottom surface of the light source 212. In other words, a part of the lead frame 212g is bent and extended to the rear or side surface of the light source 212 to be in contact with the heat absorbing layer 230.

Thus, the area where heat is released can be made larger. In detail, since the heat transferred through the lead frame 212g may be transferred to the heat absorbing layer 230 as well as the substrate 211, heat may be released more efficiently.

In this case, a heat dissipation groove 211a may be formed in the substrate 211 so that the heat absorbed by the heat absorbing layer 230 may radiate to the rear of the backlight unit 200. The heat dissipation grooves 211a may be formed between adjacent light sources 212.

In addition, the reflective sheet 220 may further include a hole corresponding to the heat radiation hole 211a to improve heat radiation performance. The heat dissipation hole 211a may be formed in a predetermined size in parallel with the light source 212.

Heat absorbed by the heat absorbing layer 230 may be transferred to the substrate 211 and the cover 290 to be discharged to the rear of the backlight unit 200. A portion of the heat absorbing layer 230 may be exposed to air by the heat dissipation hole 211a formed in the substrate 211, so that a part of the absorbed heat may be discharged to the outside of the backlight unit 200 through convection. It may be. In particular, when the connection hole 291 corresponds to the position of the heat dissipation hole 211a, heat dissipation by convection may be more smoothly performed.

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 differs in that the grooves are formed in the heat absorbing layer as compared with the first embodiment, the differences will be mainly described, and the same reference numerals and descriptions of the first embodiment will be used.

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

9, a groove 231 for diffusing light emitted from the light source 212 is formed on the heat absorbing layer 230.

The light is emitted from the light source 212 toward the upper side and a predetermined angle Θ. 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 chip 212c.

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 heat absorbing layer 230 has a refractive index of greater than one.

Light passing through two media having different refractive indices is refracted according to Snell's Law, and since the refractive index of the heat absorbing layer 230 is larger than that of air, the refractive angle is larger than the incident angle at the boundary of the groove 231. Is bigger. Therefore, a portion A of the light passing through the boundary of the groove 231 is refracted and emitted to 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 heat absorbing layer 230 (B), it is totally reflected at the boundary of the groove 231 and again Proceeds to the heat absorbing layer 230. The light propagated to the heat absorbing layer 230 may be reflected by the reflective sheet 220, may be refracted through the boundary of the adjacent 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.

On the other hand, the groove located between the grooves located above the two adjacent light sources 212 may be positioned to be able to refract the light emitted laterally from the light sources 212 on both sides. In detail, when the distance from the light emitting surface 212a to the upper end of the heat absorbing layer 230 is t, the groove located between the distances within (t X tanΘ) from the edge of the light emitting surface 212a It can be located at.

Since light emitted from the light source 212 is deflected 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 luminance of the surroundings of the light source 212 is reduced. Becomes higher. 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 heat absorbing 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 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 diffusion plate is further provided as compared with the first embodiment, the difference will be mainly described, and the same reference numerals and descriptions of the first embodiment will be used.

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

Referring to FIG. 10, a diffusion plate 240 may be further provided on the heat absorbing layer 230 of the backlight unit according to the fourth embodiment of the present invention to diffuse light passing through the heat absorbing layer 230. have. In this case, the diffusion plate 240 may be attached to the bottom surface of the optical sheet 250 and the top surface of the heat absorbing layer 230. In addition, the diffusion plate 240 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 240. In this case, the grooves formed in the diffusion plate 240 may be formed to intersect with the grooves 231 of the heat absorbing layer 230 to further increase the diffusion effect due to refraction. In this case, the diffusion plate 240 may be formed of a material having a lower refractive index than the heat absorbing layer 230 so that light is further refracted laterally.

The diffusion plate 240 may provide light having a more uniform brightness by diffusing light refracted in various patterns in the heat absorption layer 230 and supplying the light to the optical sheet 250.

Hereinafter, a backlight unit according to a fifth embodiment of the present invention will be described with reference to the drawings. However, since the fifth embodiment has a difference in that a light shielding sheet is further provided as compared with the first embodiment, the difference will be mainly described, and the same reference numerals and descriptions of the first embodiment will be used.

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

Referring to FIG. 11, a light blocking sheet 271 may be provided in the backlight unit according to the fifth exemplary embodiment of the present invention to block a part of 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 heat absorbing layer 230 and the optical sheet 250. In this case, each surface of the light blocking sheet 271 may be attached to the heat absorbing 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 blocking pattern 271a may be printed on the light blocking sheet 271 above the light source 212, and the size of the light blocking pattern 271a 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. Since the luminance of the light source 212 may be greater than that of the surroundings, a light shielding pattern 271a having a predetermined opacity may be formed above the light source 212 to reduce the luminance. 200 may be implemented to have a uniform brightness as a whole. The opacity of the light blocking pattern 271a is adjusted according to the light intensity of the light source 212.

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 sixth embodiment of the present invention will be described with reference to the drawings. However, since the sixth embodiment differs in that bubbles are further provided in the heat absorbing layer, compared to the first embodiment, the differences will be mainly described, and the same reference numerals and reference numerals are used for the same parts. .

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

Referring to FIG. 12, bubbles 237 having various sizes are formed in the heat absorbing layer of the backlight unit according to the sixth embodiment of the present invention. Since air is filled in the bubble 237, light is refracted when the light proceeds from the heat absorbing 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 heat absorbing 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 heat absorbing layer 230 may be improved. However, if the diameter of the bubble 237 is too small, the light source 212 may be used. 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, if the diameter of the bubble 237 is large, the number of the bubbles 237 is reduced, so that light is refracted in various patterns sufficiently and does not diffuse while passing through the heat absorbing layer 230. In this case, when the thickness of the heat absorbing 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 seventh embodiment of the present invention will be described with reference to the drawings. However, the seventh embodiment has a difference in that scattering particles are formed in the heat absorbing layer compared with the first embodiment, and thus, the difference will be mainly described, and the same reference numerals and reference numerals are used for the same parts. .

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

Referring to FIG. 13, the heat absorbing layer 230 of the backlight unit according to the seventh 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 heat absorbing layer 230 in order to scatter or refract light emitted from the light source 212. For example, the scattering particles 238 may be composed of polymethyl methacrylate / styrene copolymer (MS), polymethyl methacrylate, polystyrene, silicon, titanium dioxide (TiO 2), silicon dioxide (SiO 2), or the like. In addition, 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 heat absorbing layer 230.

The heat absorbing layer 230 according to the present embodiment is applied to the upper surface of the light emitting unit 210 and the reflective sheet 220 after mixing the scattering particles 238 in a liquid or gel-like resin It can be formed by post curing.

Hereinafter, a backlight unit according to an eighth embodiment of the present invention will be described with reference to the drawings. However, since the eighth embodiment has a difference in that a refractive layer is further provided inside the heat absorbing layer as compared with the first embodiment, the difference will be mainly described, and the same parts will be described with reference to the description of the first embodiment. Use it.

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

Referring to FIG. 14, the light source 212 is surrounded by a refractive layer 239 having a larger refractive index than the heat absorbing layer 230. The refractive layer 239 may be formed to be in close contact with at least the light emitting surface 212a, and may be formed to completely cover the light source 212 and to be in close contact with the reflective sheet 220.

In addition, the heat absorbing layer 230 is in close contact with the refractive layer 239 and is formed to surround the refractive layer 239.

The refractive layer 239 is formed of a light transmissive material and is formed of a material having a refractive index greater than that of the heat absorbing layer 230. Therefore, since light emitted from the light source 212 is refracted laterally in the refractive layer 239, light emitted from the light source 212 may be spread more widely.

The refractive layer 239 may be formed by applying a liquid or gel resin on top of the light source 212 and curing the composition, or may be separately manufactured and adhered to the light emitting unit 210.

Hereinafter, a backlight unit according to a ninth embodiment of the present invention will be described with reference to the drawings. However, since the ninth embodiment differs in that the heat dissipation hole and the heat dissipation film are provided in comparison with the first embodiment, the differences will be mainly described. .

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

Referring to FIG. 15, a heat dissipation hole 214 for dissipating heat is formed in the substrate 211 of the backlight unit according to the ninth 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 290 may be formed around the lead frames (212d, 212e).

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 291 formed in the cover 290 may be formed to increase the contact area with the air 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 made of a carbon nanotube (CNT) material, and may be printed or deposited on the back surface of the substrate 211. In addition, the heat dissipation hole 214 may be filled with a thermally conductive filler.

By such a structure, even when the light source 212 is surrounded by the heat absorbing layer 230, a smooth heat dissipation may be performed to the rear of the backlight unit 200.

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

Referring to FIG. 16, 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 heat absorbing 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 this 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 plan view illustrating an arrangement of the light emitting unit of FIG. 3.

5 is an exploded perspective view showing the structure of the light source of FIG.

6a and 6b are views showing the heat absorption effect by the heat absorption layer.

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

8 is a plan view illustrating an arrangement of the light emitting unit of FIG. 7.

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

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

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

12 is a partial sectional view of a backlight unit according to a sixth embodiment of the present invention;

13 is a partial sectional view of a backlight unit according to a seventh embodiment of the present invention;

Fig. 14 is a sectional view of the backlight unit according to the eighth embodiment of the present invention.

15 is a partial sectional view of a backlight unit according to a ninth embodiment of the present invention;

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

Claims (21)

Board; A plurality of light sources disposed on one side of the substrate; A heat absorption layer formed to surround the light source; And Includes an optical sheet in close contact with the heat absorbing layer, The contact surface of the heat absorbing layer and the optical sheet is formed to be spaced apart from the light source, In the light source, A case in which the light emitting diode chip is mounted; A positive lead frame and a negative lead frame connected to the light emitting diode chip and including a contact part exposed to the outside of the case and in contact with an electrode of the substrate; At least some of the contact portion is formed to extend directly below the light emitting diode chip. The method of claim 1, The length of the contact portion is a backlight unit, characterized in that formed in more than 1/2 of the longitudinal length of the case. The method of claim 1, The width of the contact portion is a backlight unit, characterized in that formed in more than 1/2 of the width of the bottom surface of the case. The method of claim 1, A portion of the contact portion is bent and extended to the side of the case to be in contact with the heat absorbing layer. The method of claim 1, And said heat absorbing layer comprises a ceramic component. The method of claim 1, And a heat generating hole disposed between the light sources adjacent to the substrate. The method of claim 1, Back light unit, characterized in that the heat dissipation film is provided on the other side of the substrate. The method of claim 7, wherein The heat dissipation film is a back light unit, characterized in that the carbon nanotube film. The method of claim 1, And a reflective sheet is attached to the substrate. The method of claim 1, And the light sources are arranged at equal intervals. The method of claim 1, The refractive index of the heat absorbing 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. 13. The method of claim 12, A cover in close contact with the rear surface of the substrate to form a rear surface of the backlight unit, And a connection hole is formed in the cover to expose the connector. The method of claim 1, And a light blocking sheet on which a light blocking pattern is printed at a position corresponding to the light source is provided on an upper surface or a lower surface of the optical sheet. The method of claim 1, The heat absorbing layer 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, A refractive layer surrounding the light source and having a refractive index larger than that of the heat absorbing layer is further included. The heat absorbing layer is a backlight unit, characterized in that formed to surround the refractive layer. 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 claim 1 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 18, 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 18, 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 20, 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.

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