KR20120030283A - Light emitting device array and backlight unit having the same - Google Patents

Abstract

PURPOSE: A luminous element array and a backlight unit including the same are provided to reduce manufacture costs by charging the inner side of a cavity with mold materials at a time and simplifying a manufacturing process. CONSTITUTION: A plurality of emitting devices(140) is mounted within a groove of a substrate. The plurality of emitting devices is electrically connected to a first metal layer(120). A cavity formation member is laminated on the substrate as a constant height. A second metal layer(150) is arranged in the lower side of the substrate. The second metal layer emits heat created from the emitting device. Mold materials(170) are charged within a cavity in order to cover the emitting device. A first reflective layer is formed on the second metal layer. A second reflective layer is formed on the inner wall of the cavity.

Description

Light emitting device array and backlight unit including same {Light emitting device array and backlight unit having the same}

The present invention relates to a light emitting device array and a backlight unit including the same.

Light-emitting devices such as light-emitting diodes (LEDs) and 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 rays can be realized by using fluorescent materials or combining colors. In addition, the light emitting device has advantages of low power consumption, semi-permanent life, fast response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps.

Therefore, a white light emitting device that can replace a fluorescent light bulb or an incandescent bulb that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of a transmission module of an optical communication means and a liquid crystal display (LCD) display device. Applications are expanding to diode lighting devices, automotive headlights and traffic lights.

BACKGROUND ART A light emitting device package having a light emitting device mounted on a package body and electrically connected to the light emitting device is widely used as a light source of a display device. In particular, a chip on board (COB) type light emitting device package is a method in which a light emitting device, for example, an LED chip is directly bonded to a substrate by die bonding and electrically connected by wire bonding, so that the light emitting device is formed on the substrate. It is widely used in the form of a plurality of light emitting element array.

Embodiments provide a light emitting device array capable of reducing manufacturing costs by simplifying a process and improving heat dissipation, and a backlight unit including the same.

The light emitting device array of the embodiment includes a substrate having a groove formed therein; A first metal layer formed on the substrate; A cavity forming member stacked on the substrate at a predetermined height; A plurality of light emitting devices mounted in the grooves of the substrate and electrically connected to the first metal layer; A second metal layer positioned below the substrate and in contact with the light emitting device to emit heat generated from the light emitting device; A mold material filled in the cavity to cover the light emitting element; Characterized in that it comprises a.

In addition, the groove is formed long in the longitudinal direction of the substrate, characterized in that the plurality of light emitting elements are arranged along the longitudinal direction of the groove.

In addition, the grooves are formed in a plurality of spaced apart from each other on the substrate, the plurality of light emitting elements are characterized in that at least one mounted in the groove.

In addition, a first reflective layer formed on the second metal layer in the groove; It characterized in that it further comprises.

In addition, a second reflective layer laminated on the inner wall of the cavity; It characterized in that it further comprises.

In addition, the cavity forming member is made of a reflective material.

In addition, the cavity forming member is characterized in that it comprises a photo solder resist (PSR).

In addition, the substrate is formed long in the longitudinal direction, characterized in that the plurality of light emitting elements are arranged along the longitudinal direction of the substrate.

In addition, the substrate is characterized in that it comprises FR4.

In addition, the mold material is characterized in that it comprises a phosphor.

In addition, the phosphor layer located above or below the mold material; It characterized in that it further comprises.

In addition, the cavity is characterized in that it has an inclined surface.

In addition, the light emitting device, the first conductivity type semiconductor layer; An active layer formed on the first conductivity type semiconductor layer; A second conductivity type semiconductor layer formed on the active layer; It includes, wherein the active layer of the light emitting device is characterized in that positioned above the top of the substrate.

In an embodiment, the backlight unit may include a light source unit including the light emitting device array; A storage device accommodating the light source unit; Characterized in that it comprises a.

The embodiment can reduce the manufacturing cost by simplifying the process and can provide a light emitting device array having improved heat dissipation characteristics and a backlight unit including the same.

1 is a cross-sectional view of a light emitting device array according to an embodiment.
2 is a schematic plan view of a light emitting device array according to another exemplary embodiment.
3 is a cross-sectional view along the AA ′ line of FIG. 2.
4 is a cross-sectional view showing a light emitting device having a general horizontal structure.
5 is a plan view illustrating a shape of a groove formed in a substrate in the light emitting device array according to the embodiment.
6 is a view showing another embodiment of a method of disposing a phosphor layer in the embodiment of FIG.
7 is a plan view illustrating a method in which wires are coupled in the light emitting device array according to the embodiment.
8 is a perspective view illustrating a display device according to an exemplary embodiment.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

In the description of the above embodiments, each layer (region), region, pattern or structures may be "on" or "under" the substrate, each layer (layer), region, pad or pattern. When described as being formed, "on" and "under" include both being formed "directly" or "indirectly". 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 a cross-sectional view of a light emitting device array according to an embodiment.

A chip on board (COB) type light emitting device package refers to a method in which a light emitting device, for example, an LED chip is directly bonded to a substrate and electrically connected by wire bonding. The light emitting device array refers to a form in which a plurality of light emitting devices are arranged on a substrate.

The light emitting device array 10 may die-bond the light emitting device 1 to one of the metal layers 21 of the patterned metal layers 21 and 22 on the upper surface of the substrate 20, and attach the light emitting device 1 to the light emitting device 1. ) Is electrically connected to another metal layer 22 by wire bonding.

In addition, the upper surface of the substrate 20 is formed by using a solder paste or a metal material to surround the light emitting device 1 to form a ring-shaped sidewall 30 of a predetermined height in a screen printing method. Next, the mold material 35 is applied to the inside of the side wall 30 at a predetermined injection amount, so that the mold material 35 is held in a dome shape having a certain height.

However, since the mold material 35 must be applied to each light emitting device 1 mounted on the substrate 20, the process is complicated and delayed.

2 is a schematic plan view of a light emitting device array according to another exemplary embodiment. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2.

Referring to FIG. 2, the substrate 110 is formed long in the longitudinal direction. In the light emitting device array 100, a plurality of light emitting devices 140 are arranged in the longitudinal direction of the substrate 110.

In this embodiment, the cavity forming member 130 having a constant height is stacked on the substrate 110 to form a cavity. In the cavity, the light emitting device 140 is mounted in a chip on board (COB) method, and the mold material 170 is filled in the cavity to cover the light emitting device 140. In this case, by filling the cavity with the mold material 170 at once, the plurality of light emitting devices 140 can be molded at once, thereby simplifying the process.

Hereinafter, the structure of the light emitting device array 100 of the present embodiment will be described in detail with reference to FIG. 3.

The light emitting device array 100 includes a substrate 110, a first metal layer 120, a cavity forming member 130, a light emitting device 140, a second metal layer 150, and a mold material 170.

A printed circuit board (PCB) may be used as the substrate 110, and more preferably, a metal core PCB (MCPCB) having excellent heat dissipation performance may be used. FR4 may be used as the material of the substrate 110. Grooves 111 are formed in the substrate 110.

The first metal layer 120 is formed on the substrate 110. The first metal layers 121, 122; 120 may be formed of two parts electrically separated from each other. The first metal layer 120 is electrically connected to the light emitting device 140, and serves to supply power to the light emitting device 140. The first metal layer 120 may be formed using a material such as aluminum, copper, gold, silver, nickel, titanium, or the like.

The cavity forming member 130 is stacked on the substrate 110 at a predetermined height to form the cavity C on the substrate 110. For example, FR4 may be used as the material of the cavity forming member 130, but is not limited thereto. The cavity forming member 130 may be stacked on both sides of the substrate in the longitudinal direction. Accordingly, the cavity C extending in the longitudinal direction is formed in the center of the substrate 110 by the cavity forming member 130. The cavity forming member 130 has an inner wall 131, and the inner wall 131 may be formed as an inclined surface or may be formed perpendicular to the substrate 110. In this embodiment, the inner wall 131 of the cavity forming member 130 is inclined.

The light emitting device 140 is mounted in the cavity C and in the groove 111 of the substrate 110 in a COB manner to be electrically connected to the first metal layer 120. Here, in the COB method, even though the light emitting device 140 is not in contact with the surface of the substrate 110, the light emitting device 140 is directly electrically connected to the first metal layer 120 formed on the substrate 110 such as a printed circuit board. It means that it is connected to receive power. The wire 145 electrically connects the light emitting device 140 with the first metal layer 120. Although a light emitting device 140 having a horizontal structure is shown in the drawing, a light emitting device having a vertical structure may be mounted in the cavity C. Light emitted from the light emitting device 140 may be reflected by hitting the inner wall 131 of the cavity C to be concentrated on an exit surface upward of the light emitting device 140, thereby improving light emission efficiency.

The phosphor layer 160 including phosphors may be stacked on the light emitting device 140 to cover the light emitting device 140. The phosphor may convert the color of light emitted from the light emitting element 140. For example, when the light emitting device 140 outputs blue light, the phosphor includes a yellow phosphor to realize white light. If the color of the light emitted from the light emitting device 140 is not blue, the color of the phosphor should also be changed to implement white light.

In addition, the mold material 170 may be stacked in the cavity C to cover the phosphor layer 160. In this case, the mold material 170 may be filled in the cavity C to cover the plurality of light emitting devices 140 arranged in the longitudinal direction on the substrate 110. By doing so, the plurality of light emitting elements 140 mounted in the cavity C can be molded at once, thereby simplifying the process and reducing the manufacturing cost. The mold member 170 may be a resin material such as epoxy or silicone. The upper surface of the mold material 170 may be formed in various shapes such as concave shape, convex shape, flat plate shape, and the directing angle of the light emitted from the light emitting device 140 may vary according to the shape of the mold material 170. .

On the other hand, the light emitting device 140 emits a lot of heat in the process of emitting light by receiving electricity. Heat emitted from the light emitting device 140 is transferred to the phosphor, thereby damaging the phosphor. When the phosphor is damaged, the color coordinate or color temperature of the light emitted from the light emitting element 140 is changed, so that light of a desired color is not emitted from the light emitting element 140. Therefore, it is an important problem to improve heat dissipation characteristics so that heat emitted from the light emitting element 140 can be well discharged to the outside.

To this end, the second metal layer 150 is disposed under the substrate 110 to be in contact with the light emitting device 140. The second metal layer 150 may be made of a metal having excellent thermal conductivity such as copper. When the light emitting device 140 disposed in the groove 111 of the substrate 110 contacts the second metal layer 150, heat generated from the light emitting device 140 may be emitted to the outside through the second metal layer 150. Can be. Therefore, it is possible to prevent a portion such as the phosphor layer 160 from being deteriorated by the heat generated from the light emitting element 140.

In order to improve the luminous efficiency, the first reflective layer 180 (or the reflective layer) may be stacked on the second metal layer 150 in the groove 111. The first reflective layer 160 serves to reflect light emitted from the light emitting device 140 in the downward direction toward the emission surface.

The reflective layer 181 may also be stacked on the wall surface of the groove 111 of the substrate 110. The reflective layer 181 reflects light emitted from the light emitting device 140 to the emission surface.

The second reflective layer 182 (or reflective layer) may be stacked on the inner wall 131 of the cavity forming member 130. The second reflective layer 182 reflects the light emitted from the light emitting element 140 and hitting the inner wall 131 of the cavity forming member 130 toward the emission surface. On the other hand, since the second reflective layer 182 is not laminated on the inner wall 131 of the cavity forming member 130, and the cavity forming member 130 is made of a reflective material that reflects light well, a similar effect can be obtained. . For example, the cavity forming member 130 may be formed of a photo solder resist (PSR), particularly a white photo solder resist (PSR).

The reflective layers 180, 181, and 182 may be formed of a photo solder resist (PSR), in particular, a white photo solder resist (PSR), but is not limited thereto. Since the reflective layers 180, 181, and 182 are increased in thickness as the stacked thickness increases, the reflective layers 180, 181, and 182 may be coated one or more times to have an appropriate thickness. In addition, the reflective layers 180, 181, and 182 effectively prevent moisture from penetrating through the interface between the components of the light emitting device array, thereby helping in terms of long-term reliability of the light emitting device array.

4 is a cross-sectional view showing a light emitting device having a general horizontal structure.

The light emitting device 140 is formed on the substrate 141, the first conductive semiconductor layer 142 provided on the substrate 141, and the first conductive semiconductor layer 142 and emits light. It may include an active layer 143 and a second conductivity type semiconductor layer 144 formed on the active layer 143. The first electrode 145 may be provided on the first conductive semiconductor layer 142, and the second electrode 146 may be provided on the second conductive semiconductor layer 144.

The active layer 143 may generate light by energy generated during recombination of electrons and holes provided from the first conductive semiconductor layer 142 and the second conductive semiconductor layer 144.

Referring back to FIG. 3, the active layer 143 mainly emits light in the light emitting device 140, and the active layer 143 of the light emitting device 140 may be positioned higher than the top of the substrate 110. . This is to improve light emission efficiency by allowing light emitted from the active layer 143 to mainly hit the upper end of the substrate 110 and be reflected toward the emission surface. That is, since the active layer 143 is formed higher than the upper end of the substrate 110, the amount of light that hits the wall surface of the groove 111 of the substrate 110 and is included in the groove 111 may be reduced.

5 is a plan view illustrating a shape of a groove formed in a substrate in the light emitting device array according to the embodiment.

Referring to FIG. 5A, grooves 111 formed in the substrate 110 are connected to each other in the longitudinal direction of the substrate 110, and the plurality of light emitting devices 140 are formed in the grooves 111. It can be arranged along the longitudinal direction of.

Referring to FIG. 5B, a plurality of grooves 111 spaced apart along the longitudinal direction of the substrate 110 are formed in the substrate 110, and the plurality of light emitting devices 140 may each have a groove 111. Can be mounted on the In this case, one light emitting device 140 is mounted in one groove 111, but a plurality of light emitting devices 140 may be mounted in one groove 111.

6 is a view showing another embodiment of a method of disposing a phosphor layer in the embodiment of FIG. In the present embodiment, the same components as those in FIG. 3 are designated by the same reference numerals.

Referring to FIG. 6A, the phosphor layer 160 may be stacked on the mold material 170 by changing the stacking order of the phosphor layer 160 and the mold material 170. In this case, the light emitted from the light emitting element 140 passes through the mold material 170 to emit light through the phosphor layer 160. As such, since the phosphor layer 160 is disposed away from the light emitting device 140, the phosphor layer 160 may be less affected by heat generated from the light emitting device 140.

Alternatively, as shown in FIG. 6B, the phosphor layer may not be disposed separately, and the mold member 170 may include the phosphor.

7 is a plan view illustrating a method in which wires are coupled in the light emitting device array according to the embodiment.

As shown in FIG. 7A, the light emitting devices 140 are spaced apart from each other along the longitudinal direction of the substrate 110, and the wires electrically connect the light emitting devices 140 to the metal layer of the substrate 110. The 145 may be disposed to form 90 ° with respect to the longitudinal direction of the substrate 110.

Alternatively, as shown in FIG. 7B, the wire 145 may be disposed to form approximately 45 ° with respect to the longitudinal direction of the substrate 110.

Alternatively, as shown in FIG. 7C, the wire 145 may be disposed in the same direction as the longitudinal direction of the substrate 110.

As such, the method of electrically connecting the light emitting device 140 to the metal layer of the substrate 110 by the wire 145 in the light emitting device array may be implemented in various forms as necessary.

8 is a perspective view illustrating a display device according to an exemplary embodiment.

The display device 500 includes an image display member 590 and a backlight unit. Here, the image display member 590 refers to a member configured to display an image by receiving light, for example, a liquid crystal panel. Hereinafter, a liquid crystal panel will be described as an example of the image display member 590.

The liquid crystal panel 590 is formed by injecting a liquid crystal layer between the TFT substrate and the color filter substrate. The liquid crystal panel 590 is arranged by placing two substrates on which electrodes are formed so that the surfaces on which the electrodes are formed face each other, injecting a liquid crystal material between the two substrates, and then applying an electric voltage to the two electrodes. By moving the liquid crystal molecules, the image is represented by the transmittance of light that varies accordingly.

The backlight unit may include a backlight assembly 510 having a light source 511, a light guide plate 520, an optical sheet 530, and a reflective sheet 540, and a storage device having a frame 550 and a lower cover 570. Can be.

The light source unit 511 is formed by mounting a light emitting device such as a light emitting diode (LED) or a cold cathode fluorescent lamp (CCFL) on a substrate, and is electrically connected to a main substrate (not shown). . The light source unit 511 may include the light emitting device array shown in the above embodiments. The light source unit 511 may be arranged at one or both edges of the light guide plate 520. Alternatively, the light source unit 511 may be formed of a direct surface light source arranged below the light guide plate 520.

The light guide plate 520 receives the light emitted from the light source unit 511 and distributes the light evenly throughout the light emitting area of the backlight. A plurality of reflective dots may be formed on the rear surface of the light guide plate 520 to diffuse the light emitted from the light source unit 511.

The optical sheet 530 is attached to the light guide plate 520, and the light emitted from the light guide plate 520 undergoes diffusion and refraction to improve brightness and light efficiency. The optical sheet 530 may be composed of one or a plurality. For example, the optical sheet 530 may include a diffusion sheet and a prism sheet, or may be configured as one optical sheet having a function of a diffusion sheet and a function of a prism sheet. have. The type and number of optical sheets 530 may be variously selected according to required luminance characteristics.

The reflective sheet 540 is disposed under the light guide plate 520 and reflects light leaking backward from the light guide plate 520 toward the light emitting area.

The liquid crystal panel 590 and the backlight assembly 510 need to be accommodated and fixed, and a frame 550, an upper cover 560, and a lower cover 570 are used for this purpose.

The frame 550 and the lower cover 570 serve to receive the backlight assembly 510. The backlight assembly 510 may include only the light source unit 511, and may further include one or more of the light guide plate 520, the optical sheet 530, and the reflective sheet 540 in addition to the light source unit 511. As such, the range of components included in backlight assembly 510 may be appropriately selected by those skilled in the art and does not limit the present invention.

The liquid crystal panel 590 may be mounted on the frame 550. The liquid crystal panel 590 is supported and received between the upper cover 560 and the frame 550. The frame 550, the upper cover 560, and the lower cover 570 may be formed of a metal or plastic material.

The light emitting device array according to the embodiment may be implemented as an indicator device or a lighting system in addition to the display device. For example, the lighting system may include a lamp and a street lamp.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated as above without departing from the essential characteristics of the present embodiment. It will be appreciated 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: light emitting element array 110: substrate
111 groove 120 first metal layer
130: cavity forming member 131: inner wall
140: light emitting element 143: active layer
145: wire 150: second metal layer
160: phosphor layer 170: mold material
180: first reflective layer 181: reflective layer
182: second reflective layer 500: display device
510: backlight assembly 511: light source unit
520: light guide plate 530: optical sheet
540: reflective sheet 550: frame
560: upper cover 570: lower cover
590 liquid crystal panel C: cavity

Claims (14)

A grooved substrate;
A first metal layer formed on the substrate;
A cavity forming member stacked on the substrate at a predetermined height;
A plurality of light emitting devices mounted in the grooves of the substrate and electrically connected to the first metal layer;
A second metal layer positioned below the substrate and in contact with the light emitting device to emit heat generated from the light emitting device;
A mold material filled in the cavity to cover the light emitting element;
Light emitting device array comprising a. The method of claim 1,
The groove is formed in the longitudinal direction of the substrate, the light emitting element array, characterized in that the plurality of light emitting elements are arranged along the longitudinal direction of the groove. The method of claim 1,
The groove is formed in the substrate spaced apart from each other a plurality of light emitting device array, characterized in that at least one mounted on the groove. The method of claim 1,
A first reflective layer formed on the second metal layer in the groove;
Light emitting device array further comprises. The method of claim 4, wherein
A second reflective layer stacked on an inner wall of the cavity;
Light emitting device array further comprises. The method of claim 1,
And the cavity forming member is made of a reflective material. The method of claim 6,
The cavity forming member includes a photo solder resist (PSR). The method of claim 1,
The substrate is formed long in the longitudinal direction, the plurality of light emitting device array, characterized in that arranged along the longitudinal direction of the substrate. The method of claim 1,
The substrate comprises a light emitting element array, characterized in that FR4. The method of claim 1,
And the mold material comprises a phosphor. The method of claim 1,
A phosphor layer located above or below the mold material;
Light emitting device array further comprises. The method of claim 1,
And the cavity has an inclined surface. The method of claim 1,
The light emitting device,
A first conductive semiconductor layer;
An active layer formed on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer formed on the active layer;
Including,
And the active layer of the light emitting device is positioned higher than an upper end of the substrate. A light source unit including the light emitting device array according to any one of claims 1 to 13;
A storage device accommodating the light source unit;
Backlight unit comprising a.

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