KR20110136651A - The backlight unit and the display device having the same - Google Patents

Abstract

PURPOSE: A display device is provided to realize the phenomena of a light entering groove which fills the LED of the integral light guiding plate. CONSTITUTION: A plurality of LEDs(21) is arranged on the bottom surface(11) of a bottom frame(10). The plurality of LED defines a plurality of light emitting areas corresponding to the display area of a liquid crystal panel(60). An integral light guiding plate(30) covers the plurality of LED. The light guiding plate is arranged on the plurality of light emitti9ng area corresponding to one screen. A plurality of grooves which accepts the LED is includes in the lower part of the light guiding plate. The groove has a variation which diffusely reflects the light of the LED.

Description

BACKLIGHT UNIT AND THE DISPLAY DEVICE CONTAINING THE SAME {THE BACKLIGHT UNIT AND THE DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a backlight unit and a display device including the same. In particular, the present invention relates to a display device in which a light emitting diode is formed as a backlight unit.

A light emitting diode (LED) may form a light emitting source using compound semiconductor materials such as GaAs series, AlGaAs series, GaN series, InGaN series, and InGaAlP series.

Such a light emitting diode is packaged and used as a light emitting device that emits a variety of colors, and the light emitting device is used as a light source in various fields such as a lighting indicator for displaying a color, a character display, and an image display.

The embodiment provides a backlight unit having a new structure and a display device including the same.

The embodiment provides a slim backlight unit and a display device including the same.

The embodiment provides a backlight unit to which a division driving method is applicable and a display device including the same.

The backlight unit according to the embodiment is a backlight unit for irradiating light to a liquid crystal panel that defines one screen as a plurality of display areas, the backlight unit is a bottom frame having a bottom surface and sidewalls, the bottom of the bottom frame An integrated light guide plate disposed on a surface, the plurality of light emitting diodes defining a plurality of light emitting regions corresponding to the display area of the liquid crystal panel, and an integrated light guide plate disposed in the plurality of light emitting regions corresponding to one screen; The integrated light guide plate includes a plurality of grooves accommodating the light emitting diodes on a lower surface thereof, and the grooves have inflections that diffusely reflect light of the light emitting diodes.

Meanwhile, the display device according to the exemplary embodiment includes a bottom frame having a bottom surface and sidewalls, a plurality of light emitting diodes formed on the bottom surface of the bottom frame and partially driven, and an integrated light guide plate formed to cover all of the light emitting diodes. And a display panel disposed on the unitary light guide plate, wherein the unitary light guide plate includes a plurality of grooves accommodating the light emitting diodes on a lower surface thereof, and the grooves have inflections that diffusely reflect light of the light emitting diodes.

According to the present invention, since the light guide plate is integrally formed to correspond to the screen of the display panel in the backlight unit driving by dividing the light emitting area, dark lines between the light guide plates do not occur and a slim backlight unit can be configured.

In addition, the present invention can reduce power consumption by providing a split driving method such as local dimming or impulsive, and can improve screen contrast to improve image quality of the display device.

In addition, since the light guide plate is integrally formed, manufacturing cost can be reduced, and the hot spot can be improved by implementing the shape of the light receiving groove filling the light emitting diode of the integrated light guide plate through various embodiments.

1 is an exploded perspective view of a display device according to a first exemplary embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II ′ of the display device of FIG. 1, illustrating a first application example of the groove portion. FIG.
3 is a perspective view illustrating the light source unit of FIG. 1.
4 illustrates a simplified cross-sectional view of the display device of FIG. 2.
5 is a cross-sectional view showing a second application example to the groove portion in the first embodiment.
6 is a plan view illustrating a split driving method of a backlight unit of a display device according to an exemplary embodiment of the present invention.
7 is a cross-sectional view of a display device according to a second exemplary embodiment of the present invention.
8 to 10 are cross-sectional views showing various applications of the groove portions of the second embodiment.
11 is a cross-sectional view of a display device according to a third exemplary embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

In order to clearly illustrate the present invention in the drawings, thicknesses are enlarged in order to clearly illustrate various layers and regions, and parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification .

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part is "just above" another part, there is no other part in the middle.

In the display device, the light guide plate constituting the backlight unit to be dividedly driven is formed in a one-body corresponding to the entire screen of the display panel.

Hereinafter, a display device according to a first exemplary embodiment of the present invention will be described with reference to FIGS. 1 to 5.

1 is an exploded perspective view of a display device according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II ′ of the display device of FIG. 1, illustrating a first application example of a groove part. FIG. 3 is a perspective view illustrating the light source unit of FIG. 1, FIG. 4 is a simplified cross-sectional view of the display device of FIG. 2, and FIG. 5 is a cross-sectional view illustrating a second application example to the groove part of the first embodiment.

The display device according to the first embodiment includes a backlight unit and a display panel that receives light from the backlight unit and displays an image. Therefore, the backlight unit will also be described below by describing the display device.

1 to 4, the display device according to the first exemplary embodiment includes a bottom frame 10, a light emitting module formed in the bottom frame 10, a reflective sheet 25, and a light guide plate 30.

The display device includes a light emitting module, a reflective sheet 25, and a light guide plate 30 formed on the light emitting module and the reflective sheet 25 to form a light emitting unit, and the optical sheet 40 and the optical sheet 40 on the light guide plate 30. The top frame 70 is formed on the display panel 60 and the display panel 60.

The bottom frame 10 is vertically extended from the bottom surface 11 and the bottom surface 11 having a planar shape of a rectangular shape having two long sides and two short sides facing each other and perpendicular to each other. Sidewalls 12.

The bottom frame 10 is coupled to the fixing member 50 formed on the optical sheet 40 to store the light emitting module, the reflective sheet 25, the light guide plate 30, and the optical sheet 40 in the bottom frame 10. do.

The bottom frame 10 may be formed of, for example, a metal material, and a plurality of convex portions (not shown) may be formed on the bottom surface 11 to enhance rigidity.

In the bottom frame 10, the reflective sheet 25 and the plurality of light emitting modules alternately extend in the X-axis direction on the bottom surface 11.

Each light emitting module has a bar type and includes a module substrate 20 extending in the X-axis direction and a plurality of light emitting diodes 21 formed in rows on each module substrate 20.

The module substrate 20 is made of a metal core PCB, FR-4 PCB, a general PCB, a flexible substrate or a ceramic substrate, and can be variously changed within the technical scope of the embodiment.

The module substrate 20 may supply power to each of the light emitting diodes 21 to provide light to the light guide plate 30, so that the light emitting diodes 21 may be individually driven.

Meanwhile, a plurality of light emitting modules may be disposed in a bar type as shown, or may be formed of a single substrate having a size corresponding to the front surface of the bottom frame 10.

The plurality of light emitting diodes 21 arranged on the module substrate 20 are disposed in the groove 31 of the light guide plate 30 in a side view type that emits light laterally with respect to the module substrate 20. Light is emitted to the side of the groove 31.

The light emitting diode 21 may be a colored LED that emits at least one of colors such as red, blue, green, white, or the like, or may be implemented as a UV LED. In this case, the colored LED may include a red LED, a blue LED, a green LED, a white LED, and the arrangement and emission light of the light emitting diode 21 may be changed within the technical scope of the embodiment.

The reflective sheet 25 is made of a reflector, a reflective metal plate, or the like, and reflects light leaked from the light guide plate 30 again. The reflective sheet 25 is formed to be exposed between the module substrates 20, and as illustrated in FIG. 2, a plurality of separated reflective sheets 25 may be formed in a spaced area between the module substrates 20.

A plurality of heat dissipation members (not shown) may be further formed between the light emitting unit and the bottom frame 10.

In the display device, a light guide plate 30 is formed on the plurality of light emitting modules and the plurality of reflective sheets 25 to diffuse and reflect light emitted from the light emitting diodes 21 and irradiate the display panel 60 with a surface light source. have.

The light guide plate 30 includes an upper surface and a lower surface. An upper surface of which the surface light source is generated is flat, and a plurality of grooves 31 are formed in the lower surface to accommodate the light emitting diodes 21.

The groove part 31 has an edge type which consists of the 1st surface 31a, the 2nd surface 31b, and the intersection 31c which the 1st surface 31a and the 2nd surface 31b meet.

 The first surface 31a may be an inclined surface that is inclined at a predetermined angle with respect to the flat upper surface of the light guide plate 30, and the second surface 31b may be a surface perpendicular to the upper surface of the light guide plate 30.

The second surface 31b is an incident surface facing the side emitting light of the light emitting diode 21, and the inclined surface that is the first surface 31a receives light incident on the second surface 31b which is the incident surface. Guide to the top of 30).

The first surface 31a has an inflection so as to have a distance longer than the linear distance from the intersection with the second surface 31b to the intersection 31c.

The first surface 31a is formed to protrude convexly toward the bottom frame 10 to reduce hot spots by diffusely reflecting light from the first surface 31a.

The first surface 31a may be formed to be recessed toward the bottom frame 10 as shown in FIG. 5, and the inclined first surface 31a is formed to have a concave inflection to increase diffuse reflection of light.

The intersection 31c is equal to the length in the longitudinal direction of the groove 31. That is, when one groove part 31 accommodates the plurality of light emitting diodes 21 forming one row, the intersection 31c may have a length from one end to the other end of the light guide plate 30.

At this time, the groove portion 34 (circular dotted line in FIG. 4) located at the end of the groove portion 31 at the end of the light guide plate 30 opposite to the direction of light emission of the light emitting diode 21 is formed to have a rectangular cross section. Can be.

2 to 5, the light emitting diodes 21 accommodated in the grooves 31 of the light guide plate 30 are disposed in close proximity to the second surface 31b of the grooves 31, and the adjacent second surfaces ( 31b) to emit light. In addition, the reflective sheet 25 is formed below the first surface 31a of the groove portion 31 and is not formed on the second surface 31b which is the light incident surface.

As described above, the plurality of grooves 31 are formed on the lower surface of the light guide plate 30, and at least one light emitting diode 21 is disposed in each of the grooves 31, so that divided driving may be performed while providing improved light uniformity.

The light guide plate 30 is divided into a plurality of light emitting areas EA, and the size of each light emitting area EA depends on the number of light emitting diodes 21 emitting light to each light emitting area. Is defined.

That is, when each light emitting diode 21 is individually driven as shown in FIG. 1, the light emitting area EA may be a part of the light guide plate 30 in which one light emitting diode 21 is located. When the light emitting diodes 21 are driven at the same time, the sum of the portions of the light guide plate 30 in which the plurality of light emitting diodes 21 driven at the same time may be defined as one light emitting area EA.

The light guide plate 30 does not have a body separated for each of the light emitting regions EA, and is formed in a one-body shape covering all of the light emitting diodes 21 formed in the bottom frame 10.

That is, although the light guide plate 30 includes a plurality of divided light emitting regions EA, the light guide plate 30 is not physically divided but is driven by the light emitting diode 21 positioned in the corresponding light emitting region EA.

As described above, when the light guide plate 30 corresponding to one screen of the display panel 60 is divided and driven to form an integrated body, dark lines between the light guide plates 30, which are physically separated from each light emitting area EA, are generated. Instead, the fastening part is simplified, and thus a slim backlight unit can be provided.

In addition, the present invention can reduce power consumption by providing a divided driving method such as local dimming and impulsive, and can improve screen contrast to improve image quality of the display device.

In addition, according to the present invention, by dividing and driving by using the light guide plate 30 formed integrally, the light quantity distribution can be clearly controlled through the divided light emitting area EA. In addition, by driving the light emitting diodes 21 for each region, different luminance may be irradiated for each of the divided light emitting regions EA, and the display device may have excellent image quality.

The light guide plate 30 is made of a transparent material, and may include, for example, one of an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), and polyethylene naphthalate (PEN) resin. Can be.

The integrated light guide plate 30 may be integrally formed with an injection molding method or an extrusion method with respect to the display panel 60 constituting one screen.

Meanwhile, a diffusion pattern (not shown) may be formed on the upper surface of the light guide plate 30.

The optical sheet 40 is disposed on the light guide plate 30.

For example, the optical sheet 40 may include a first diffusion sheet 41, a prism sheet 42, and a second diffusion sheet 43. The diffusion sheets 41 and 43 diffuse light emitted from the light guide plate 30, and the diffused light is collected by the prism sheet 42 into the light emitting region EA. Here, the prism sheet 42 may be selectively configured using a horizontal or / and vertical prism sheet, one or more brightness enhancing films, or the like.

The optical sheet 40 may not be formed, and only one diffusion sheet 41 or 43 may be formed, or only one prism sheet 42 may be formed. The number and type of the optical sheets 40 can be variously selected according to the required luminance characteristics.

 The support member 50 is formed on the optical sheet 40.

The support member 50 is coupled to the bottom frame 10 to allow the reflective sheet 25, the light emitting module, the light guide plate 30, and the optical sheet 40 to be received in close contact with the bottom frame 10. The display panel 60 is supported.

The support member 50 may be formed of a synthetic resin material or a metal material, for example.

The display panel 60 is disposed on the supporting member 50.

The display panel 60 displays image information by light irradiated from the light guide plate 30. For example, the display panel 60 may be implemented as a liquid crystal display panel. The display panel 60 may include an upper substrate, a lower substrate, and a liquid crystal layer interposed between the two substrates, and may further include polarizing sheets adhered to the upper surface of the upper substrate and the lower surface of the lower substrate, respectively.

 The display panel 60 may be driven by being divided into a plurality of display areas DA corresponding to a local dimming driving method or an impulsive driving method. In this case, the display area DA and the light guide plate of the display panel may be driven. The emission area EA of 30 may correspond to that shown in FIG. 4.

The top frame 70 is formed on the display panel 60.

The top frame 70 includes a front part disposed on the front of the display device and a side part bent in a vertical direction from the front part and disposed on the side of the display device, and the side part includes the support member 50 and a screw (not shown). It can be coupled via a coupling member such as.

1 to 5, the display device according to the first embodiment of the present invention includes a backlight unit including a light guide plate 30 integrated with a divided display area DA of the display panel 60. Perform the dividing drive.

Hereinafter, dividing driving of the backlight unit will be described with reference to FIG. 6.

6 is a plan view illustrating a split driving method of a backlight unit of a display device according to an exemplary embodiment of the present invention.

The backlight unit of the display device of FIGS. 1 to 5 may be driven by a split driving method, and the split driving method may include a local dimming method or an impulsive method.

When the display device is driven by a local dimming method, the display panel 60 is divided into a plurality of display areas, and thus the light emitting part also has a plurality of light emitting areas EA.

Each light emitting area EA may be defined as a portion A of the light guide plate 30 in which two neighboring light emitting diodes 21 are located, as shown in FIG. 6, whereas each light emitting diode 21 has one light emitting diode 21. The light emitting area EA may be defined, or NXM (N, M may be any integer) light emitting diodes 21 may define one light emitting area EA.

The luminance of at least one light emitting diode 21 positioned in each light emitting area EA may be individually adjusted according to the gray peak value of each light emitting area EA. The light emitting diode 21 corresponding to the portion A of the light guide plate 30, which is EA, is selectively driven.

 Meanwhile, when the display device is driven in an impulsive manner, the divided light emitting regions EA may be sequentially turned on in synchronization with the display panel in time.

The division driving of the display device may be variously changed according to the circuit design of the light emitting diode 21, but the present invention is not limited thereto.

Hereinafter, a display device according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 7 to 10.

7 is a cross-sectional view of a display device according to a second exemplary embodiment of the present invention, and FIGS. 8 to 10 are cross-sectional views illustrating various application examples of the groove part of the second exemplary embodiment.

Referring to FIG. 7, the display device according to the second exemplary embodiment of the present invention is the optical sheet 40, the fixing member 50, and the display panel on the light guide plate 30 like the display device illustrated in FIGS. 1 to 5. 60 and the top frame 70, a description thereof will be omitted.

The display device illustrated in FIG. 7 includes a reflective sheet 25 and a light emitting module on the bottom frame 10, and includes an integrated light guide plate 30 covering the reflective sheet 25 and the light emitting module.

In this case, the integrated light guide plate 30 includes a flat upper surface for providing a surface light source to the display panel 60 and a lower surface on which the plurality of grooves 35 are formed.

In the display device illustrated in FIGS. 7 to 10, unlike the light guide region between the groove 35 and the groove 35, the light guide plate 30 of the flat type has a plate shape parallel to the upper surface. ).

In this case, the groove 35 of the integrated light guide plate 30 may have various shapes as well as a rectangular shape, may have a pentagonal shape as shown in FIG. 7, may have a trapezoidal shape as shown in FIG. 8, and FIG. 9. It may have a hexagonal shape as shown, and may have a circular, semi-circular shape as shown in FIG.

The shape of the groove part 35 of the light guide plate 30 is not limited thereto, and may be formed in a polygonal shape having a plurality of angles. In this way, the shape of the groove part 35 may be varied so that the light incident surface of the light guide plate 30 is light-emitting diode 21. In the case of inflection with respect to the light, the light is diffusely reflected to reduce the hot spot.

The light emitting diodes 21 are respectively accommodated in the grooves 35 of the light guide plate 30, and the light emitting diodes 21 emit light toward one side of the grooves 35.

At this time, the light emitting diode 21 is closer to the side emitting the light than the distance to the opposite side.

As described above, when the flat light guide plate 30 is formed, the structure is simple and can be easily manufactured. The light emitting diodes 21 are fixed to the respective grooves 35 so that the light emitting diodes 21 can be easily fixed. Do.

In addition, since the light guide region of the light guide plate 30 is flat, it is easy to form an optical pattern such as a scattering pattern or a prism pattern.

The flat light guide plate 30 is divided into a plurality of light emitting regions, and the size of each light emitting region is defined according to the number of light emitting diodes 21 irradiating light to the corresponding light emitting regions.

The light guide plate 30 does not have a body separated for each light emitting region, and is formed integrally.

That is, although the light guide plate 30 includes a plurality of divided light emitting regions, the light guide plate 30 is not physically divided but is driven by the LED 21 positioned in the corresponding light emitting region.

As such, when the light guide plate 30 corresponding to one screen of the display panel 60 is divided and driven to form an integrated body, dark lines between the light guide plates 30 which are physically separated and generated for each light emitting area do not occur. Since the fastening part is simplified, a slim backlight unit can be provided.

In addition, in the case of forming the integrated light guide plate 30 having the flat groove 35, manufacturing is simplified, and a split driving method such as local dimming or impulsive can be provided to reduce power consumption and to display a screen. The image quality of the display device may be improved by improving contrast.

Hereinafter, a display device according to a third exemplary embodiment of the present invention will be described with reference to FIG. 11.

7 to 10, since the light emitting diodes 21 inject light toward the side surfaces of the grooves 35 of the light guide plate 30, the grooves 35 as shown in FIG. 11. The shape of may be formed asymmetrically.

That is, the cross section of the groove portion 35 of the integrated light guide plate 30 is not formed symmetrically with respect to the Y axis, and the right half portion where the incident surface for incidence of light is formed has a plurality of angles so as to have an inflection as shown in FIGS. 7 to 10. It may have a shape or have a slope, the left half may be formed in a rectangular shape along the shape of the light emitting diode (21).

As described above, the inflexion is formed only in the groove part 35 on which the light is incident, thereby improving the hot spot and easily manufacturing the integrated light guide plate 30.

Although the embodiments of the present invention have been described above in detail, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the range.

10: bottom frame,
20: reflective sheet,
30: light guide plate,
40: optical sheet,
50: support member,
60: display panel,
70: top frame

Claims (14)

A backlight unit for irradiating light to a liquid crystal panel that defines one screen as a plurality of display regions,
The backlight unit,
Bottom frame with bottom and side walls,
A plurality of light emitting diodes disposed on the bottom surface of the bottom frame and defining a plurality of light emitting regions corresponding to the display regions of the liquid crystal panel;
An integrated light guide plate covering the plurality of light emitting diodes and disposed in the plurality of light emitting regions corresponding to one screen;
The integrated light guide plate may include a plurality of grooves accommodating the light emitting diodes on a lower surface of the light guide plate, and the grooves may have an inflection to diffusely reflect light of the light emitting diodes. The method of claim 1,
And a light emitting diode accommodated in the groove so that light enters the side of the groove. The method of claim 2,
The cross section of the groove has a first surface inclined with respect to the upper surface of the integrated light guide plate and a second surface perpendicular to the upper surface of the integrated light guide plate,
And the first surface is convexly formed toward the bottom frame. The method of claim 2,
The cross section of the groove has a first surface inclined with respect to the upper surface of the integrated light guide plate and a second surface perpendicular to the upper surface of the integrated light guide plate,
And the first surface is concave with respect to the bottom frame. The method of claim 2,
And a light guide region that is flat with respect to an upper surface of the integrated light guide plate between the groove portion and the adjacent groove portion, and an inflection is formed on a side surface of the groove portion. The method of claim 5,
A cross-section of the groove portion is a backlight unit is formed of a polygon or semicircle. The method of claim 5,
The groove unit has a curved portion formed only on the side of the light incident to the light emitting diode. Bottom frame with bottom and side walls,
A plurality of light emitting diodes formed on the bottom surface of the bottom frame and partially driven;
An integrated light guide plate covering all of the plurality of light emitting diodes;
A display panel disposed on the integrated light guide plate;
The integrated light guide plate may include a plurality of grooves accommodating the light emitting diodes on a lower surface of the integrated light guide plate, and the grooves may have an inflection to diffusely reflect light of the light emitting diodes. The method of claim 8,
And a light emitting diode accommodated in the groove to allow light to enter the side of the groove. 10. The method of claim 9,
The cross section of the groove has a first surface inclined with respect to the upper surface of the integrated light guide plate and a second surface perpendicular to the upper surface of the integrated light guide plate,
The first surface is convexly formed toward the bottom frame. 10. The method of claim 9,
The cross section of the groove has an inclined first surface inclined with respect to the upper surface of the integrated light guide plate and a second surface perpendicular to the upper surface of the integrated light guide plate,
The first surface is concave. 10. The method of claim 9,
And a light guide region that is flat with respect to an upper surface of the integrated light guide plate between the groove portion and the adjacent groove portion, and a side surface of the groove portion has an inflection. The method of claim 12,
A cross section of the groove portion is formed in a polygon or semicircle. The method of claim 12,
The groove has a curved portion formed only on the side of the light incident to the light emitting diode.

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