KR20080050707A - Backlight module and display device having the same - Google Patents

Abstract

A backlight module and a display device having the backlight module are provided to integrate a light-reflecting layer with the top face of a substrate on which point light sources are mounted such that an additional member such as a reflecting sheet is omitted to reduce the number of components of the backlight module. A backlight module(200) includes a substrate(210), a plurality of point light sources(220), and a light-reflecting layer(240). The point light sources are mounted on the substrate and project light. The light-reflecting layer is formed on the top face of the substrate, integrated with the substrate and reflects light upward. The backlight module further includes a heat-radiating plate(260) formed on the bottom face of the substrate and integrated with the substrate. The backlight module further includes first and second adhesive layers(230,250). The first adhesive layer is interposed between the top face of the substrate and the light-reflecting layer. The second adhesive layer is interposed between the bottom face of the substrate and the heat-radiating plate.

Description

BACKLIGHT MODULE AND DISPLAY DEVICE HAVING THE SAME}

1 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

2 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

3 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

4 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

5 is a cross-sectional view of a display device according to an exemplary embodiment of the present invention.

6 is a cross-sectional view of a display device according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

210: substrate 211: upper surface

213: surface 220: point light source

230: first adhesive layer 240: light reflection layer

245 transparent resin layer 250 second adhesive layer

260: heat sink 100, 200, 400, 600: backlight module

510: power supply board 570, 770: storage container

571: bottom plate 575: side wall

590 optical sheet 680 light guide plate

The present invention relates to a backlight module and a display device having the same. More particularly, the present invention relates to a backlight module having improved light utilization efficiency and heat dissipation efficiency and a display device having the same.

In general, the backlight assembly employed in the liquid crystal display is classified into an edge type back light assembly and a direct downward type back light assembly according to the arrangement of the light sources.

 In the case of an edge type backlight assembly, the light source is disposed on the side of the light guide plate. The direct type backlight assembly is a structure mainly developed as the size of the display device is enlarged, and one or more light sources are arranged under the diffuser to diffuse the light to irradiate the entire surface with the back of the display panel. The direct type backlight assembly has an advantage of ensuring high luminance because multiple light sources can be used as compared to the edge type backlight assembly.

Liquid crystal displays, such as laptops and monitors, typically include a cold cathode fluorescent lamp (CCFL) as a light source of the backlight assembly, but have a low power consumption as a backlight light source of a display device such as a laptop and a monitor. It is a trend to adopt a light emitting diode having the advantages of light weight and slim.

Since the light emitting characteristics of the light emitting diodes are sensitive to temperature, the substrate on which the light emitting diodes are mounted is typically disposed on a heat sink. In addition, a reflective sheet is used to reflect light emitted from the light emitting diode. Openings into which the light emitting diodes are inserted are formed in the reflective sheet. When the heat sink, the substrate, and the reflective sheet are separately configured as described above, there is a problem in that light leaks due to a gap between the reflective sheet and the substrate. In addition, there is a problem that other members for fixing the heat sink, the substrate and the reflective sheet configured separately.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a backlight module having improved light utilization efficiency and heat dissipation efficiency.

Another object of the present invention is to provide a display device including the backlight module.

In order to achieve the above object of the present invention, a backlight module includes a substrate, a plurality of point light sources, and a light reflection layer. Point light sources are mounted on the upper surface of the substrate to emit light. The light reflection layer is integrally formed with the substrate on the upper surface of the substrate to reflect light upward.

In one embodiment, the backlight module may further include a heat sink. The heat sink is integrally formed with the substrate on the lower surface of the substrate. The backlight module may further include a first adhesive layer and a second adhesive layer. The first adhesive layer is interposed between the upper surface of the substrate and the light reflection layer. The second adhesive layer is interposed between the lower surface of the substrate and the heat sink. The light reflection layer may include a silver (Ag) layer or an aluminum (Al) layer. The backlight module may further include a transparent resin layer formed integrally with the light reflection layer on the light reflection layer. The substrate may be a flexible printed circuit board (FPC). Alternatively, the substrate may include a heat dissipation layer, an insulation layer, and power wiring. The heat dissipation layer is attached to the second adhesive layer, and the insulating layer is interposed between the heat dissipation layer and the first adhesive layer. Power wiring is insulated by an insulating layer and is electrically connected to the point light sources. The backlight module may further include a container and an optical sheet. The containment vessel includes a bottom plate and sidewalls extending from the periphery of the bottom plate. The heat sink is disposed on the bottom plate, and the backlight module may further include an optical sheet disposed on the point light sources. Alternatively, the heat sink may be disposed on the sidewalls, and the backlight module may further include a light guide plate. The light guide plate may include a side facing the point light sources, a back surface facing the bottom plate, and a light exit surface facing the back surface.

In order to realize the above object of the present invention, the display device according to the embodiment includes a light output module, a storage container, an optical unit, and a display panel. The light output module includes a substrate, a plurality of point light sources, a first adhesive layer, a light reflection layer, a second adhesive layer, and a heat sink. Point light sources are mounted on the upper surface of the substrate to emit light. The first adhesive layer is formed on the upper surface of the substrate, and the light reflection layer is attached to the first adhesive layer to reflect light upward. The second adhesive layer is formed on the lower surface of the substrate, and the heat sink is attached to the second adhesive layer. The storage container has one surface facing the heat sink and accommodates the light output module. The optical unit is stored in the storage container so as to face the point light sources. The display panel is disposed above the optical unit.

According to the backlight module and the display device having the same, the light utilization efficiency and the heat radiation efficiency of the backlight module can be improved.

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

Backlight module

1 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

Referring to FIG. 1, the backlight module 100 includes a substrate 10, a plurality of point light sources 20, and a light reflection layer 40.

The substrate 10 electrically connects the external power source and the point light source 20. The substrate 10 may be a flexible printed circuit board (FPC). Therefore, the substrate 10 may include an insulating film and a power wiring patterned inside the insulating film. The insulating film may be a plastic film having excellent ductility and electrical insulation, such as polyester (PET) and polyimide (PI). The substrate 10 may have a rectangular plate shape.

Alternatively, the substrate 10 may include a heat dissipation layer, an insulation layer, and power wiring. The insulating layer is formed on the heat dissipation layer. Power supply wiring is insulated by an insulating layer. The heat dissipation layer may be made of a metal such as aluminum or a nonmetal such as graphite. When the heat dissipation layer includes a metal layer, the substrate 10 may be defined as a metal core printed circuit board (MCPCB).

The point light sources 20 are mounted on the top surface 11 of the substrate 10. Each point light source 20 may include a housing 21 which is a mold, a light emitting chip 23 accommodated in the housing 21, and a protective layer 25 covering the light emitting chip 23. The light emitting chip 23 is electrically connected to the power wiring to receive driving power. Light emitted from the light emitting chip 23 passes through the protective layer 25 and is emitted to the outside. The point light source 20 may include a red light emitting chip, a green light emitting chip, and a blue light emitting chip. Alternatively, the point light source 20 may include a white light emitting chip that emits white light. Obviously, the type of the point light source 20 may be modified in various ways.

The backlight module 100 may further include an adhesive layer 30. The adhesive layer 30 is formed on the upper surface 11 of the substrate 10 except for the region where the point light sources 20 are disposed. The adhesive layer 30 may be a sheet type in which a plurality of openings are formed corresponding to the point light sources 20, and may be attached to the upper surface 11 of the substrate 10. Alternatively, the adhesive layer 30 may be formed by applying an adhesive to the upper surface 11 of the substrate 10. The adhesive layer 30 may include a member having excellent thermal conductivity and electrical insulation, for example, heat dissipation silicone.

  The light reflection layer 40 is attached on the adhesive layer 30 to reflect the light emitted from the point light source 20 and reflected by the optical sheet to the top again. Therefore, since the light reflection layer 40 is not spaced apart from the upper surface 11 of the substrate 10, the gap from which light can leak is greatly reduced. Therefore, the light utilization efficiency of the backlight module 100 is improved.

The light reflection layer 40 may include a metal layer or a nonmetal layer. The metal layer may include a silver (Ag) layer or an aluminum (Al) layer. The light reflection layer 40 may be attached to the adhesive layer 30 in a sheet type. In another embodiment, the adhesive layer 30 may be omitted, and the light reflection layer 40 may be directly coated on the upper surface 11 of the substrate 10. Therefore, the light emitted from the point light source 20 can be effectively reflected upward without using a separate member such as a reflective sheet.

The light reflection layer 40 is preferably formed in the middle or bottom of the housing 21 of the point light source 20 so as not to interfere with the light output through the protective layer 25 of the point light source 20. When the light reflection layer 40 includes a metal layer such as a silver (Ag) layer or an aluminum (Al) layer, the light reflection layer 40 may function as a heat dissipation layer that radiates heat generated from the point light source 20. . Therefore, even if a separate heat sink is not disposed on the lower surface 13 of the substrate 10, heat generated from the point light source 20 can be effectively released.

In another embodiment, the adhesive layer 30 may be removed and the light reflection layer 40 may be formed by directly applying or plating the upper surface 11 of the substrate 10. Alternatively, the sheet type light reflection layer 40 may be pressed onto the upper surface 11 of the substrate 10 to be integrated with the substrate 10.

The backlight module 100 may further include a transparent resin layer 45. The transparent resin layer 45 may be integrally formed with the light reflection layer 40 on the light reflection layer 40. The transparent resin layer 45 prevents the light reflection layer 40 from being damaged due to oxidation or scratching.

2 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

Referring to FIG. 2, the backlight module 200 may include a substrate 210, a plurality of point light sources 220, a first adhesive layer 230, a light reflection layer 240, a transparent resin layer 245, and a second adhesive layer ( 250 and a heat dissipation plate 260. The backlight module 200 may be substantially the same as the backlight module 100 illustrated in FIG. 1 except that the backlight module 200 further includes a second adhesive layer 250 and a heat sink 260.

Accordingly, the point light sources 220 are mounted on the top surface 211 of the substrate 210, and the first adhesive layer 230 is formed on the top surface 211 of the substrate 210 except for the region where the point light sources 220 are mounted. do. The light reflection layer 240 is disposed or formed on the first adhesive layer 230. The transparent resin layer 245 is formed on the light reflection layer 240.

The second adhesive layer 250 is adhered to the bottom surface 213 of the substrate 210. Like the first adhesive layer 230, the second adhesive layer 250 may be attached to the lower surface 213 as a sheet type. Alternatively, the second adhesive layer 250 may be formed by applying an adhesive to the lower surface 213 of the substrate 210.

The heat sink 260 is attached to the second adhesive layer 250. The heat sink 260 may be made of a metal such as aluminum or a nonmetal material such as graphite. The heat sink 260 emits heat generated while the point light source 220 emits light to the outside of the backlight module 200.

Therefore, the light reflection layer 240 and the heat sink 260 both function as a heat radiation. The light reflection layer 240 emits heat conducted to the upper surface 211 of the substrate 210 to the outside, and the heat sink 260 emits heat conducted to the lower surface 213 of the substrate 210 to the outside.

Therefore, the heat radiation efficiency of the backlight module 200 is further improved, and a separate member such as a reflective sheet may be omitted.

3 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

Referring to FIG. 3, the backlight module 400 may be used as a backlight light source of the direct backlight assembly. The backlight module 400 includes a substrate 410, a plurality of point light sources 420, a first adhesive layer 430, a light reflection layer 440, a transparent resin layer 445, a second adhesive layer 450, and a heat sink 460. ), A storage container 570 and an optical sheet 590. The substrate 410, the plurality of point light sources 420, the first adhesive layer 430, the light reflection layer 440, the transparent resin layer 445, the second adhesive layer 450, and the heat sink 460 are shown in FIG. 2. Can be substantially identical to those made.

The storage container 570 includes a bottom plate 571 and a side wall 575. The storage container 570 may be a chassis made of metal. The heat sink 460 is disposed on the bottom plate 571, and may be in direct contact with the bottom plate 571. The backlight module 400 may further include a heat radiation pad. A heat dissipation pad may be further disposed between the heat dissipation plate 460 and the bottom plate 571 to improve contact characteristics.

Heat emitted from the point light source 420 is emitted upward through the first adhesive layer 430, the light reflection layer 440, and the transparent resin layer 445. The heat discharged in this way may be mostly discharged through the bottom plate 571 and the side wall 575 of the storage container 570. In addition, the heat emitted from the point light source 420 is discharged to the outside of the storage container 570 through the second adhesive layer 450, the heat sink 460 and the bottom plate 571.

The backlight module 400 may further include a frame 580.

The frame 580 may have a quadrangular frame shape opened in the vertical direction. The frame 580 may include an upper surface portion that covers an upper end of the side wall 575 of the storage container 570 and a side portion that faces the side wall 575. An upper step portion may be formed with a stepped portion.

The optical sheet 590 is supported by the stepped portion. The optical sheet 590 may include a diffusion plate 591, a diffusion sheet 593, and a light collecting sheet 595 sequentially stacked.

The diffusion plate 591 and the diffusion sheet 593 diffuse the light emitted from the point light sources 420. When the point light source 420 emits white light, the diffusion plate 591 and the diffusion sheet 593 improve the luminance uniformity of the light. When the red light, the green light, and the blue light are respectively emitted according to the point light sources 420, the diffusion plate 591 and the diffusion sheet 593 may mix light to form white light, thereby improving luminance uniformity. The light collecting sheet 595 improves the front luminance of the emitted light.

Most of the light emitted from the point light source 420 passes through the optical sheet 590, but part of the light may be reflected at the interface of the optical sheet 590. The reflected light is reflected back upward in the light reflection layer 440.

The backlight module 400 may further include a power supply substrate 510. The power supply substrate 510 may be disposed on the rear surface of the bottom plate 571 and may be electrically connected to the substrate 410 through the connector 520. The power supply substrate 510 outputs driving power of the point light sources 420.

The combination of the substrate 410, the point light sources 420, the first adhesive layer 430, the light reflection layer 440, the transparent resin layer 445, the second adhesive layer 450 and the heat sink 460 as a light output module define. The backlight module 400 may include a plurality of light output modules.

In another embodiment, the heat sink 460 may be removed and the substrate 410 may be directly contacted with the bottom plate 571, or may be in contact with the heat radiating pad that is in contact with the bottom plate 571. In this case, in order to improve heat radiation efficiency, the light reflection layer 440 may be extended between the adjacent substrates 410 to contact the bottom plate 571.

4 is a cross-sectional view of a backlight module according to an embodiment of the present invention.

Referring to FIG. 4, the backlight module 600 may be used as a backlight light source of an edge type backlight assembly. The backlight module 600 includes a light output module, a storage container 770, a light guide plate 680, and an optical sheet 790.

The light output module includes a substrate 610, a plurality of point light sources 620, a first adhesive layer 630, a light reflection layer 640, a transparent resin layer 645, a second adhesive layer 650, and a heat sink 660. Include. The substrate 610, the plurality of point light sources 620, the first adhesive layer 630, the light reflection layer 640, the transparent resin layer 645, the second adhesive layer 650, and the heat sink 660 are shown in FIG. 2. Each of which may be substantially the same.

The storage container 770 and the optical sheet 790 may be substantially identical to those shown in FIG. 3, respectively.

The backlight module 600 may further include a frame 780. The frame 780 may include a side portion and a bottom portion. The side portion faces the inner side of the side wall 775 of the storage container 770. The lower surface portion extends from the lower end of the side portion and faces the bottom plate 771. The side portion is formed with an opening into which the light output module is inserted.

The heat sink 660 may be fixed to the side wall 775 of the storage container 770. The point light sources 620 are exposed to the inside of the storage container 770 through an opening formed in the side portion of the frame 780.

The light guide plate 680 is accommodated in the storage container 770. The light guide plate 680 may include a side surface facing the point light sources 620, an opposite surface facing the bottom plate 771, and a light exit surface facing the opposite surface.

The optical sheet 790 is supported by the stepped portion formed in the side portion of the frame 780. The optical sheet 790 may further include a reflective sheet 690 disposed between the light guide plate 680 and the bottom plate 771.

The light emitted from the point light source 620 is guided upward by the light guide plate 680 and passes through the optical sheet 790.

The light reflection layer 640 is disposed or formed on the substrate 610, and may have a heat radiating function. Therefore, a separate member such as a light reflection plate may be omitted around the point light source 620, and the light utilization efficiency and heat radiation efficiency of the backlight module 600 may be improved.

Display

5 is a cross-sectional view of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the display device 800 includes a light output module, a storage container 970, a frame 980, an optical sheet 990, a display panel 940, and a top chassis 950.

The light output module, the container 970, the frame 980 and the optical sheet 990 may be substantially the same as those described in FIG.

The display panel 940 may be supported by another step portion formed at the side portion of the frame 980. The display panel 940 may include a lower substrate 941 on which pixel parts are formed, an upper substrate 945 on which color filter parts opposing the pixel parts, and a liquid crystal layer interposed between both substrates.

The top chassis 950 covers the edge of the display panel 940 and is fastened to the storage container 970 or the frame 980.

As described in detail above, according to the present invention, the light reflection layer is integrally formed on the upper surface of the substrate on which the point light sources are mounted, so that a separate member such as a reflective sheet can be omitted, and the light reflection layer is also a heat radiation layer. Since it can function, the heat sink that can be disposed on the lower surface of the substrate can be omitted. Therefore, the number of single components of the backlight module can be reduced, and light utilization efficiency and heat radiation efficiency can be improved.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (10)

A substrate including an upper surface and a lower surface facing the upper surface; A plurality of point light sources mounted on the upper surface to emit light; And And a light reflection layer formed integrally with the substrate on the upper surface to reflect the light upward. The backlight module of claim 1, further comprising a heat sink formed integrally with the substrate on the lower surface. The semiconductor device of claim 2, further comprising: a first adhesive layer interposed between the upper surface and the light reflection layer; And The backlight module further comprises a second adhesive layer interposed between the lower surface and the heat sink. The backlight module of claim 3, wherein the light reflection layer comprises a silver (Ag) layer or an aluminum (Al) layer. The backlight module of claim 4, further comprising a transparent resin layer formed integrally with the light reflection layer on the light reflection layer. The backlight module of claim 3, wherein the substrate is a flexible printed circuit board (FPC). The method of claim 3, wherein the substrate A heat dissipation layer attached to the second adhesive layer; An insulation layer interposed between the heat dissipation layer and the first adhesive layer; And And a power wiring insulated by the insulating layer and electrically connected to the point light sources. The storage container of claim 2, further comprising: a bottom plate on which the heat dissipation plate is disposed and a side wall extending from a peripheral portion of the bottom plate; And The backlight module further comprises an optical sheet disposed on the point light sources. The storage container of claim 2, further comprising: a storage container including a bottom plate and a sidewall extending from a periphery of the bottom plate and on which the heat sink is disposed; And And a light guide plate including a side facing the point light sources, an opposite surface facing the bottom plate, and a light exiting surface facing the opposite surface. A substrate, a plurality of point light sources mounted on an upper surface of the substrate to emit light, a first adhesive layer formed on the upper surface, a light reflection layer attached to the first adhesive layer to reflect the light upwards, and formed on a lower surface of the substrate A light emitting module including a second adhesive layer and a heat sink attached to the second adhesive layer; A storage container having one surface facing the heat sink and accommodating the light output module; An optical unit housed in the storage container so as to face the point light sources; And And a display panel disposed above the optical unit.

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