KR20120070825A - Light emitting device and backlight unit including the same - Google Patents

Abstract

PURPOSE: A light emitting device module and a backlight unit with the same are provided to reduce hot spots and increase the uniformity of brightness. CONSTITUTION: A circuit board includes a first side(135a) and a second side(135b). At least one first light emitting package(133) is arranged on the first side. The first light emitting device package emits light in a horizontal direction with the first side. At least one second light emitting device package(131) is arranged on the second side. The second light emitting device package emits light in a direction vertical to the second side.

Description

LIGHT EMITTING DEVICE AND BACKLIGHT UNIT INCLUDING THE SAME}

An embodiment relates to a light emitting device module and a backlight unit including the same.

Light-emitting devices such as light-emitting diodes (LEDs) or laser diodes (LDs) using semiconductors of Group 3-5 or 2-6 compound semiconductor materials of semiconductors have been developed through the development of thin film growth technology and device materials. Various colors such as green, blue, and ultraviolet light can be realized, and efficient white light can be realized by using fluorescent materials or combining colors, and low power consumption, semi-permanent life, and quicker than conventional light sources such as fluorescent and incandescent lamps can be realized. It has the advantages of response speed, safety and environmental friendliness.

Therefore, the light emitting diode can replace a light emitting diode backlight, a fluorescent lamp or an incandescent bulb which replaces a cold cathode fluorescent lamp (CCFL) constituting a backlight module of an optical communication means, a backlight of a liquid crystal display (LCD) display device. Applications are expanding to white light emitting diode lighting devices, automotive headlights and traffic lights.

The embodiment seeks to improve optical characteristics of the backlight unit.

Embodiments include a circuit board including a first surface and a second surface; At least one side view light emitting device package disposed on the first surface; And at least one top view light emitting device package disposed on the second surface and emitting light in the same direction as the direction of light emitted from the side view light emitting device package. . Here, the light emitting device disposed on the first surface and the light emitting device disposed on the second surface may be driven independently of each other.

The amount of light emitted from the side view light emitting device may have a maximum value in a direction parallel to the first surface.

The amount of light emitted from the top view light emitting device may have a maximum value in a direction perpendicular to the second surface.

The first and second surfaces may be vertical.

The first light emitting device and the second light emitting device may be alternately arranged at least once.

In addition, two first light emitting device packages and one second light emitting device package adjacent to each other may receive a current from one driving unit.

At least two first light emitting devices and one second light emitting device may be alternately disposed.

In addition, two second light emitting device packages and one first light emitting device package adjacent to each other may receive a current from one driving unit.

At least two second light emitting devices and one first light emitting device may be alternately disposed.

The first light emitting device package and the second light emitting device package corresponding to each other may receive a current from one driving unit.

The first light emitting device and the second light emitting device may be disposed to correspond to each other at least once.

The first light emitting device package and the second light emitting device package may emit light toward the light guide plate.

The circuit board may be a flexible circuit board.

In addition, the first and second surfaces of the circuit board may be coupled to each other.

Another embodiment includes a substrate patterned with a conductive material, the substrate comprising a first surface and a second surface continuous to each other; At least one side view light emitting device disposed on the first surface; And a light emitting device module including at least one top view light emitting device disposed on the second surface. A reflection sheet reflecting light emitted from the light emitting device module; And it provides a backlight unit comprising a light guide plate for transmitting the light incident from the light emitting device module and the reflective sheet.

In the light emitting device module and the backlight according to the embodiment, since the side view light emitting device package and the top view light emitting device package are alternately arranged or correspond to each other, it is expected to reduce the hot spot of the entire backlight unit and improve the uniformity of brightness. Can be. In addition, each package may be driven independently to supply light separately to each area of the panel.

1 is an exploded perspective view of an embodiment of a display device;
FIG. 2 is a cross-sectional view of an embodiment of the backlight unit of FIG. 1;
3A is a cross-sectional view of an embodiment of a top view light emitting device package;
Figure 3b is a perspective view of an embodiment of a side view light emitting device package,
4 is a view schematically showing an embodiment of the arrangement of the light emitting device package in the backlight unit of FIG.
5A to 7C are views showing other embodiments of the arrangement of the light emitting device package in the backlight unit of FIG.
8 is a cross-sectional view of another embodiment of a backlight unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiments, each layer, region, pattern, or structure is formed “on” or “under” a body, each layer, region, pad, or pattern. In the case where it is described as, “on” and “under” include both “directly” or “indirectly” formed through another layer. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

1 is an exploded perspective view of an embodiment of a display device.

As shown, the display device 100 according to the present exemplary embodiment includes a light emitting device module (not shown), a backlight unit 110, and light disposed in front of the backlight unit 110 and transmitted from the light emitting device module. A diffusion sheet 140 for guiding the front of the display device, a first prism sheet 150 and a second prism sheet 160 disposed in front of the diffusion sheet 140, and the second prism sheet 160. And a color filter 180 disposed in front of the panel 170 and the panel 170.

The configuration of the light emitting device module and the backlight unit 110 including the same will be described later. The diffusion sheet 140, the first prism sheet 150, and the second prism sheet 160 form an optical sheet, which may be formed of another combination, for example, a micro lens array or a diffusion sheet and a micro lens. Or a combination of one prism sheet and a micro lens array.

The diffusion sheet 140 may be made of a polyester and polycarbonate-based material, and may maximize the light projection angle through refraction and scattering of light incident from the backlight unit. The diffusion sheet 140 includes a support layer including a light diffusing agent, a first layer formed on a light exit surface (first prism sheet direction) and a light incident surface (reflective sheet direction), and including no light diffusing agent. And a second layer.

And, the support layer is 0.1 to 10 weight of siloxane light diffusing agent having an average particle diameter of 1 to 10 micrometers with respect to 100 parts by weight of the resin mixed with methacrylic acid-styrene copolymer and methyl methacrylate methyl-styrene copolymer Part, 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of 1 to 10 micrometers may be included.

The first layer and the second layer may be included in an amount of 0.01 to 1 part by weight of an ultraviolet absorber and 0.001 to 10 parts by weight of an antistatic agent based on 100 parts by weight of the methyl methacrylate-styrene copolymer resin.

In addition, the thickness of the support layer in the diffusion sheet 140 may be 100 ~ 10000 micrometers, the thickness of each layer may be 10 ~ 1000 micrometers.

In addition, the first prism sheet 150 is formed of a translucent and elastic polymer material on one surface of the support film, and the polymer may have a prism layer in which a plurality of three-dimensional structures are repeatedly formed. Here, the plurality of patterns may be provided in the stripe type and the valley repeatedly as shown.

In addition, the direction of the floor and the valley of one surface of the support film in the second prism sheet 160 may be perpendicular to the direction of the floor and the valley of one surface of the support film in the first prism sheet 150. This is to evenly distribute the light transmitted from the light emitting device module and the reflective sheet in all directions of the panel 170.

Although not shown, a protective sheet may be provided on each prism sheet, and a protective layer including light diffusing particles and a binder may be provided on both surfaces of the support film. In addition, the prism layer is made of a polymer material selected from the group consisting of polyurethane, styrene butadiene copolymer, polyacrylate, polymethacrylate, polymethylmethacrylate, polyethylene terephthalate elastomer, polyisoprene, polysilicon Can be.

A liquid crystal display panel may be disposed on the panel 170. In addition to the liquid crystal display panel, another type of display device that requires a light source may be provided.

The panel 170 is in a state in which a liquid crystal is positioned between the glass bodies and the polarizing plates are placed on both glass bodies in order to use polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

The liquid crystal display panel used in the display apparatus uses a transistor as a switch for regulating a voltage supplied to each pixel as an active matrix method.

In addition, the front surface of the panel 170 is provided with a color filter 180 to transmit the light projected by the panel 170, only the red, green and blue light for each pixel can represent an image.

2 is a cross-sectional view of an embodiment of the backlight unit of FIG. 1. The backlight unit 110 according to the embodiment includes the light emitting device module 130, the reflective sheet 120, and the light guide plate 125.

In the light emitting device module 130, a first light emitting device package 133 and a second light emitting device package 131 are disposed on the substrates 135a and 135b, and the substrates 135a and 135b are printed circuit boards. A board may be used, and a conductive material may be patterned to supply current to the light emitting device packages 131 and 133.

Here, the substrate may be a flexible printed circuit board, or two substrates 135a and 135b manufactured independently may be combined to form an integrated body.

The substrate is composed of two surfaces, one surface 135b having a top view second light emitting device package 131 disposed thereon, and the other surface 135a having a side view. The first light emitting device package 133 is disposed. Here, in the side view type light emitting device package, the amount of light emitted is mainly emitted in a horizontal direction with the surface 135a, and the direction in which the light amount has a peak, that is, a maximum value, is also in a horizontal direction. The light emitting device package may have a peak amount of light emitted mainly in a direction perpendicular to the direction of the surface 135b.

At this time, the two surfaces of the substrate are provided perpendicular to each other, one surface (hereinafter referred to as the first surface, 135a) is provided in the direction parallel to the reflective sheet 120 and the light guide plate 125, the other The surface (hereinafter referred to as a second surface, 135b) may be provided in a direction perpendicular to the reflective sheet 120 and the light guide plate 125. In addition, the first surface 135a and the second surface 135b may be continuous without being separated from each other.

The top view second light emitting device package 131 is disposed on the second surface 135b perpendicular to the reflective sheet 120 and the light guide plate 125, and has a side view first light emitting device package ( 133 is disposed on the first surface 135a that is horizontal to the reflective sheet 120 and the light guide plate 125 so that all of the light emitted from the second light emitting device package 131 and the first light emitting device package 133 may be disposed. The reflective plate 120 may face the light guide plate 125.

In addition, since the light emitted from the second light emitting device package 131 should be incident to the light guide plate 125 without being blocked by the first light emitting device package 133, the light emitted from the second light emitting device package 131 is emitted. The first light emitting device package 133 should not be disposed within a range of directing angles of light. In addition, the second light emitting device package 131 and the first light emitting device package 133 may be disposed so that the direction of the direction of the light emitted from each of them is directed toward the light guide plate 125.

3A is a cross-sectional view of an embodiment of a top view light emitting device package 131.

As shown, the light emitting device package 131 according to the embodiment includes a package body (a), a first electrode layer (b) and a second electrode layer (b ') provided on the package body (a), and the package body The light emitting device (c) according to the embodiment provided in (a) and electrically connected to the first electrode layer (b) and the second electrode layer (b '), and the resin layer (e) surrounding the light emitting device (c). ).

The package body (a) may include a silicon material, a synthetic resin material, or a metal material. An inclined surface (f) may be formed around the light emitting device (c) to increase light extraction efficiency. Then, the light emitted from the light emitting device (c) by the inclined surface (f) mainly proceeds to the upper direction based on Figure 3a. That is, the inclined surface (f) forms a cavity (caity) in the package body (a), so that the light emitted from the light emitting element (c) disposed in the cavity can proceed in the upper direction in Figure 3a.

The first electrode layer b and the second electrode layer b 'are electrically separated from each other, and provide power to the light emitting device c. In addition, the first electrode layer (b) and the second electrode layer (b ') can increase the light efficiency by reflecting the light generated from the light emitting device (c), the heat generated from the light emitting device (c) It may also play a role in discharging to the outside.

The light emitting device c may be installed on the package body a or on the first electrode layer b or the second electrode layer b '.

The light emitting device c may be electrically connected to the first electrode layer b and the second electrode layer b 'by any one of a wire d method, a flip chip method, and a die bonding method.

The resin layer (e) may surround and protect the light emitting device (c). In addition, the resin layer (e) may include a phosphor to change the wavelength of light emitted from the light emitting device (c).

3B is a perspective view of an embodiment of a side view light emitting device package.

As shown, the side view light emitting device package 133 may include a light emitting device mounted on the body a, the first electrode layer b, the second electrode layer b, and the second electrode layer b '. c), a reflection surface f formed on the body a to reflect laterally the light emitted from the light emitting device c, and a number surrounding the light emitting device c; Strata (e).

The light emitting device package 133 of the side view type is reflected from the inclined surface f emitted from the light emitting device c, and mainly proceeds to the side in FIG. 3B.

As shown in FIG. 2, light emitted from the first light emitting device package 133 and the second light emitting device package 131 travels in the direction of the reflective sheet 120 and the light guide plate 125. In addition to the above-described configuration, the backlight unit 110 may include an optical sheet such as a diffusion sheet, a prism sheet, or a micro lens array.

FIG. 4 is a view schematically illustrating an embodiment of arranging a light emitting device package in the backlight unit of FIG. 2.

The first light emitting device package 133 and the second light emitting device package 131 constituting the light emitting device module may be alternately arranged at least once, and in FIG. 4, they are alternately arranged once each.

In this case, the first light emitting device package 133 is disposed on a circuit board parallel to the light guide plate 125, and the second light emitting device package 131 is disposed on a circuit board perpendicular to the light guide plate 125. The first light emitting device package 133 and the second light emitting device package 131 are arranged in a zigzag manner with each other, and such an arrangement is well shown in a perspective view of the right side.

Here, the circuit board 135a on which the first light emitting device package 133 is disposed and the circuit board 135b on which the second light emitting device package 131 is disposed are made of the same material. The circuit board 135b on which the light emitting device package 131 is disposed is shown differently, and the same applies to the following drawings.

The light guide plate 125 and the circuit board 135a are supported by the bottom cover 121, and the reflective sheet is not visible because it is the same size as the light guide plate 125.

The light emitted from the first light emitting device package 133 and the second light emitting device package 131 both travel in the same direction, that is, in the direction of the reflective sheet 120 and the light guide plate 125. The light guide plate 125 evenly transmits light in a direction of a panel or an optical sheet (not shown), and the reflective sheet 120 is disposed under the light guide plate 125, and the reflective sheet 120 is disposed on the light guide plate 125. Send the light back to. Here, the direction of the panel or optical sheet is the direction of the panel 170 or the diffusion sheet 140 in FIG. 1.

The above-described arrangement of the side view type first light emitting device package 133 and the top view type second light emitting device package 131 may be arranged in each light emitting device package in a light source module. The top view may be alternately arranged to prevent light from being concentrated in a specific area of the light guide plate 125 or the panel, thereby preventing hot spots and increasing the overall brightness.

FIG. 5A is a diagram illustrating another embodiment of an arrangement of a light emitting device package in the backlight unit of FIG. 2.

In the present embodiment, the first light emitting device package 133 and the second light emitting device package 131 are driven independently of each other, and the first light emitting device package 133 and the second light emitting device package 131 are each a circuit board. Are disposed on different faces 135a and 135b, respectively. That is, the side view type first light emitting device package 133 is connected to one driving unit D _S , and the top view type second light emitting device package 131 is connected to the other driving unit D _T. .

Therefore, in the backlight unit according to the exemplary embodiment, since the first light emitting device package 133 and the second light emitting device package 131 are alternately driven, the brightness of the entire panel may be adjusted. That is, since the driving unit D _{S is} connected to the first light emitting device package 133 and the other driving unit D _{T is} connected to the second light emitting device package 131, the first light emitting device package 133 is provided. The luminance of the panel may be adjusted by supplying current to only one group of the second light emitting device packages 131 or supplying current to the whole.

FIG. 5B is a view illustrating another embodiment of the arrangement of the light emitting device package in the backlight unit of FIG. 2.

In the present embodiment, each of the light emitting device packages 131 and 133 is connected to different driving units D ₁₁ to D ₂₄ . Accordingly, since each of the light emitting device packages 131 and 133 may be individually driven, light may be individually supplied to specific regions R ₁₁ to R ₂₄ of the light guide plate, thereby enabling local dimming.

In the present exemplary embodiment, eight light emitting device packages 131 and 133 are provided, and thus the light guide plate 125 and the corresponding panel (not shown) are divided into eight regions, but may be divided into eight or more or less. One area may correspond to each light emitting device package driven. In addition, although each of the regions R ₁₁ to R ₂₄ is divided by a dotted line, the regions are not artificially divided by the light guide plate 125 or the panel. The division of these areas is the same in the above-described embodiment and the following embodiment.

5C is a view illustrating another embodiment of the arrangement of the light emitting device package in the backlight unit of FIG. 2.

In the present exemplary embodiment, the light guide plate 125 to the panel (not shown) are divided into two regions R ₁ and R ₂ , but one light emitting device package 131 and 133 corresponding to one region R ₁ has one. The light emitting device packages 131 and 133 connected to the driving unit D ₁ and corresponding to the other region R ₂ are all connected to the other driving unit D ₂ .

Therefore, the amount of light supplied to the two regions of the light guide plate 125 to the panel can be easily adjusted.

6A and 6B illustrate another embodiment of the arrangement of the light emitting device package in the backlight unit of FIG. 2, and the arrangement of the light emitting device packages in each embodiment is shown in a perspective view on the right side of each drawing.

In the present exemplary embodiment, the first light emitting device package 133 and the second light emitting device package 131 constituting the light emitting device module are alternately disposed. In FIG. 6A, one first light emitting device is provided for each of the first light emitting device package 133. 2, the light emitting device package 131 is disposed, and in FIG. 6B, one first light emitting device package 133 is disposed per two second light emitting device packages 131. This arrangement is a side view type first light emitting device package. In consideration of the optical characteristics of the first and second top light emitting device packages 131 and 131, a plurality of light emitting device packages may be disposed. That is, when a dark portion occurs in the light guide plate region between the first light emitting device package 133 of the top view method, the side view light emitting device package 131 may be disposed in the corresponding area. In addition, by alternately arranging light emitting device packages of different types instead of the same type of light emitting device packages, the light incident on the light guide plate may be even. In this case, the number of top view and side view light emitting device packages having different numbers may be evenly disposed. In addition, the above-described arrangement is not only a one-to-two or two-to-one correspondence between the side view type light emitting device package and the top view type light emitting device package, but also the side view type and top view type light emission such as one to three or three to one. Device packages can be placed in different ways.

FIG. 6C is a view showing another embodiment of the arrangement of the light emitting device package in the backlight unit of FIG. 2, and the arrangement of the light emitting device packages in this embodiment is shown in a perspective view on the right side.

In the present exemplary embodiment, the first light emitting device package 133 and the second light emitting device package 131 are disposed to correspond to each other at least once. That is, in another embodiment, the first light emitting device package 133 and the second light emitting device package 131 are not overlapped vertically in the drawing. The amount of light can be increased.

FIG. 7A is a diagram illustrating an embodiment of supplying current to the backlight unit of FIG. 6A.

In this embodiment, a total of three driving units D ₁ , D ₂ , and D ₃ are disposed, and each of the first light emitting device packages 133 and 1 is provided in each of the driving units D ₁ , D ₂ , and D ₃ . Second light emitting device packages 131 are connected to each other. Therefore, three light emitting device packages correspond to the three regions R ₁ , R ₂ , and R _{3 of the} light guide plate 125 to the panel (not shown).

However, the light emitting device packages of the arrangement illustrated in FIG. 6A do not necessarily have the current supply structure of FIG. 7A, and only one embodiment for local dimming is illustrated in FIG. 7A.

FIG. 7B is a diagram illustrating an embodiment of supplying current to the backlight unit of FIG. 6B.

In this embodiment, a total of three driving units D ₁ , D ₂ , and D ₃ are disposed, and each of the second light emitting device packages 131 and 1 is provided in each of the driving units D ₁ , D ₂ , and D ₃ . First LED package 133 is connected. Therefore, three light emitting device packages correspond to the three regions R ₁ , R ₂ , and R _{3 of the} light guide plate 125 to the panel (not shown).

However, the light emitting device packages of the arrangement illustrated in FIG. 6B do not necessarily have the current supply structure of FIG. 7B, and only one embodiment for local dimming is illustrated in FIG. 7B.

FIG. 7C is a diagram illustrating an embodiment of supplying current to the backlight unit of FIG. 6C.

In the present exemplary embodiment, the first light emitting device package 133 and the second light emitting device package 131 are disposed to correspond to each other at least once. The second light emitting device package 131 corresponds to one driving unit D ₁ to D ₆ . In addition, six light-emitting device packages correspond to _six regions R ₁ to R _{6 of the} light guide plate 125 to a panel (not shown).

8 is a cross-sectional view of another embodiment of a backlight unit.

This embodiment is similar to the embodiment shown in FIG. 2, but the light emitting device modules are provided on both sides of the reflective sheet and the light guide plate 125 to form a two-edge method. In addition, the reflective sheet is composed of a plurality of layers. In the present embodiment, the reflective sheet is composed of four layers 120a to 120d, and the reflective sheet disposed on the upper portion becomes narrower in width. The reflective sheet composed of a plurality of arrays has a thickness of about 0.1 millimeter (mm) in one layer, and the reflective sheet located on the upper side corresponds to the center of the light guide plate 125, so that the light projected from the light emitting device module 130 is increased. May be evenly reflected in the light guide plate 125.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

100: display device 110: backlight unit
120, 120a ~ 120d: Reflective sheet 121: Batam cover
125: light guide plate
130: light emitting device module 131: second light emitting device package
133: first light emitting device package 135a, 135b: substrate
140: diffusion sheet 150, 160: first, second prism sheet
170: panel 180: color filter
a: body b, b ': first and second electrodes
c: light emitting element d: wire
e: resin layer f: reflective surface
D: drive unit

Claims (16)

A circuit board comprising a first surface and a second surface;
At least one first light emitting device package disposed on the first surface and emitting light in a horizontal direction with the first surface; And
At least one second light emitting device package disposed on the second surface and emitting light in a direction perpendicular to the second surface;
The light emitting device package having the same direction as the light emitted from the first light emitting device package and the direction of the light emitted from the second light emitting device package. The method of claim 1,
The light emitting device module disposed on the first surface and the light emitting device package disposed on the second surface are driven independently of each other. The method of claim 1,
The amount of light emitted from the side view light emitting device package has a maximum value in a direction parallel to the first surface. The method of claim 1,
The amount of light emitted from the top view light emitting device package has a maximum value in a direction perpendicular to the second surface. The method of claim 1,
The first surface and the second surface of the light emitting device module perpendicular to each other. The method of claim 1,
And the first light emitting device package and the second light emitting device package are alternately disposed at least once. The method of claim 1,
At least two first light emitting device packages and one second light emitting device package are alternately disposed; The method of claim 7, wherein
2. The light emitting device module of which two first light emitting device packages adjacent to each other and one second light emitting device package receive current from one driving unit. The method of claim 1,
At least two of the second light emitting device package and one of the first light emitting device package is disposed alternately with each other. The method of claim 9,
2. The light emitting device module of which two second light emitting device packages adjacent to each other and one first light emitting device package receive current from one driving unit. The method of claim 1,
The first light emitting device package and the second light emitting device package is disposed at least once corresponding to each other. The method of claim 11,
The light emitting device module corresponding to the first light emitting device package and the second light emitting device package receives a current from one driving unit. The method of claim 1,
The first light emitting device package and the second light emitting device package is a light emitting device module for emitting light toward the light guide plate. The method of claim 1,
The circuit board is a light emitting device module that is a flexible circuit board. The method of claim 1,
The circuit board is a light emitting device module coupled to the first surface and the second surface. The light emitting device module of any one of claims 1 to 15;
A reflection sheet reflecting light emitted from the light emitting device module; And
And a light guide plate transferring light incident from the light emitting device module and the reflective sheet.

Images