KR102000072B1 - luminescence Device - Google Patents

Abstract

An embodiment of the present invention relates to a light emitting device for use in a backlight unit for illumination or display, wherein a side surface of a heat dissipation layer exposed to the outside is covered with a protective layer to suppress ion migration, The reliability and life of the product can be improved. Further, the stress of the molded wire between the electrode pad and the electrode layer can be reduced.
The light emitting device according to the first embodiment includes a substrate, first and second electrode layers on which a pattern is formed, a heat dissipation layer formed on the first electrode layer, a light emitting layer formed on the heat dissipation layer, An electrode pad formed on a predetermined region of the light emitting layer; a wire connected between the electrode pad and the second electrode layer; a cover disposed on the substrate outside the first and second electrode layers; And a protective layer formed on the substrate and the first and second electrode layers in the cover, the protective layer being formed at substantially the same height as the heat dissipation layer.

Description

[0001] The present invention relates to a luminescence device,

An embodiment of the present invention relates to a light emitting device used in a backlight unit for illumination or display.

2. Description of the Related Art In general, a light emitting diode (hereinafter referred to as 'LED') is formed by using a compound semiconductor material such as GaAs, AlGaAs, GaN, InGaN and AlGaInP to form a light emitting source, It says.

As a criterion for determining the characteristics of the LED element, there are a high output light emission and luminance, and a range of a luminescent color. The characteristics of the LED element are determined primarily by the compound semiconductor material used in the LED element, but also by the structure of the package for mounting the chip with the secondary element. In order to obtain high brightness and brightness according to user's demand, there is a limit to only the primary factors due to the development of materials, so that the package structure has attracted much attention.

1 is a cross-sectional view showing a conventional light emitting device.

1, the conventional light emitting device 10 includes a substrate 11, first and second electrode layers 12 and 13, a heat dissipation layer 14, a light emitting layer 15, a phosphor layer 16, The heat dissipation layer 14 is formed on the back surface of the light emitting layer 15 in order to dissipate heat generated in the light emitting layer 15 to the outside, Respectively.

Although the heat dissipation layer 14 uses tungsten (W) for the purpose of improving heat dissipation, the use of molybdenum (Mo) as an alternative material is increasing. However, the molybdenum (Mo) has a problem of causing ion migration to an electric field and distilled water, and the oxide film peels off when a high temperature furnace is used.

Therefore, when the side surface of the heat dissipation layer 14 is exposed to the outside as shown in FIG. 1, if the heat dissipation layer 14 is formed of molybdenum (Mo), the ion migration and the oxide film dissolution And thus the reliability and life of the product are deteriorated.

Domestic registered patent No. 0845856 (Registered on Jul.07, 2008)

In order to solve the above-described problems, it is an object of the present invention to provide a light emitting device capable of improving the reliability and lifetime of a product.

It is another object of the present invention to provide a light emitting device capable of solving the problem of ion migration due to a heat dissipation layer exposed to the outside and peeling of an oxide film.

It is another object of the present invention to provide a light emitting device capable of reducing the stress of a wire molded between an electrode pad and an electrode layer.

The solution to the problem of the present invention is not limited to those mentioned above, and other solutions not mentioned can be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, there is provided a light emitting device comprising: a substrate; first and second electrode layers having a pattern formed on the substrate; a heat dissipation layer formed on the first electrode layer; A light emitting layer formed on the light emitting layer, a phosphor layer formed on the light emitting layer, an electrode pad formed on a predetermined region of the light emitting layer, a wire connected between the electrode pad and the second electrode layer, A cover disposed on the substrate, and a protective layer formed on the substrate and the first and second electrode layers, the protective layer being formed at substantially the same height as the heat dissipation layer.

According to another aspect of the present invention, there is provided a light emitting device comprising: a substrate; first and second electrode layers on which a pattern is formed; a heat dissipation layer formed on the first electrode layer; A light emitting layer formed on the heat dissipation layer, a phosphor layer formed on the light emitting layer, an electrode pad formed on a predetermined region of the light emitting layer, a wire connected between the electrode pad and the second electrode layer, A barrier rib formed on the substrate outside the first electrode layer; and a barrier rib formed on the first electrode layer between the barrier rib and the heat-releasing layer, the barrier rib being formed on the first electrode layer, And a protective layer formed on the substrate.

Here, the heat dissipation layer may be formed of any one of metals including tungsten (W) and molybdenum (Mo). The heat dissipation layer may have a thickness of about 65 μm to about 95 μm.

The protective layer may be formed of a resin or an inorganic material. The protective layer may be formed to have the same height as the heat dissipation layer or a height that can cover at least 80% of the side surface of the heat dissipation layer.

The barrier rib may be formed between the first electrode layer and the wire connected to the second electrode layer. The partition wall may have the same height as the heat dissipation layer or be formed higher than the heat dissipation layer. The partition may have a hemispherical shape, a semi-elliptical shape, a semicircular shape, a quadrangle, and a quadrangle having a chamfer at an upper corner.

The cover may be formed of a light-transmitting polymer or glass.

The light emitting layer may include at least one of a colored LED chip and a UV chip.

At least one kind of phosphor may be added to the phosphor layer.

The substrate may be made of any one of ceramic, polymer, resin, silicon, and metal.

According to the embodiment, the side surface of the heat-radiating layer exposed to the outside is covered with the protective layer to suppress the occurrence of ion migration and oxide film peeling, thereby improving the reliability and life of the product.

Further, the stress of the molded wire between the electrode pad and the electrode layer can be reduced.

Further, by using a resin having a high reflectance as the protective layer, the light flux can be prevented from being lowered, and occurrence of ion migration from the heat dissipation layer can be suppressed by using a resin having low gas permeability.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a cross-sectional view of a conventional light emitting device
2 is a cross-sectional view of the light emitting device according to the first embodiment
3 is a cross-sectional view of the light emitting device according to the second embodiment

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

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

First Embodiment

2 is a cross-sectional view of the light emitting device according to the first embodiment.

2, the first embodiment 100 of the light emitting device includes a substrate 111, first and second electrode layers 112 and 113, a heat dissipation layer 114, a light emitting layer 115, a phosphor layer 116 An electrode pad 117, a wire 118, a cover 119,

The substrate 111 serves as a body of the light emitting device and may be formed of a ceramic material, a polymer material, a resin material, a silicon material, a metal material, or the like.

The light emitting device may be classified as a ceramic package, a plastic package, a silicon package, a metal package, or the like depending on the material used as the substrate 111. The material to be used for the substrate 111 can be selected in consideration of heat radiation effect, mass production possibility, cost, characteristics of other components, purpose and use of the product, and other various matters.

For example, when silicon is used as the substrate material of the light emitting device, a package can be laminated in multiple layers, and a circuit can be mounted between the lamination portions. In addition, when a silicon substrate is used, it can be manufactured in a wafer-level integrated form with a low dependency on reflectance due to a light emission wavelength, and thus it is advantageous in mass production of multiple products.

The substrate 111 may be formed by injection molding a polymer material, a resin material, a ceramic material, a silicon material, or the like on a press (Cu / Ni / Ag substrate). When the substrate 111 is made of the ceramic material, it may be made of alumina (Al ₂ O ₃ ).

A driving circuit (not shown) for driving the light emitting layer 115 may be mounted in the substrate 111. The driving circuit drives the light emitting layer 115 to perform a desired function according to the purpose and use of the light emitting device.

On the other hand, an insulating layer (not shown) may be disposed on the substrate 111. The insulating layer interrupts the electrical connection between the substrate 111 and the first and second electrode layers 112 and 113. However, when the substrate 111 is made of a nonconductive material, an insulating layer may not be formed.

Subsequently, the first and second electrode layers 112 and 113 may be patterned on the substrate 111. The first and second electrode layers 112 and 113 are formed of electrodes for electrically connecting to the light emitting layer 115 and may be patterned to be electrically connected to a driving circuit for driving the light emitting layer 115. That is, the first and second electrode layers 112 and 113 serve as electric wires for connecting the components in the light emitting device.

More specifically, the first and second electrode layers 112 and 113 may include an anode and a cathode electrode for driving the light emitting layer 115. The first and second electrode layers 112 and 113 serve to serve as an electrode and reflect light emitted from the light emitting layer 115 to increase light efficiency. For this, the first and second electrode layers 112 and 113 may be surface-treated to be advantageous for mixing color light emitted from the light-emitting layer 115.

In addition, the first and second electrode layers 112 and 113 may radiate heat generated by the light emitting layer 115 to the outside.

In order to perform such a function, the first and second electrode layers 112 and 113 may be formed of a conductive material. For example, the first and second electrode layers 112 and 113 may be formed of at least one selected from the group consisting of Cu, Ag, Au, Ni, Al, Cr, Ru, Re, Pb, Cr, Sn, In, Zn, Pt, Mo, At least one kind of metal selected from the group including metals, and alloys containing these metals.

For example, when the first and second electrode layers 112 and 113 are formed with a pattern of silver (Ag) to increase the light flux, the silver (Ag) .

In addition, the first and second electrode layers 112 and 113 may be patterned through an etching process or a printing process.

Next, the heat dissipation layer 114 may be formed on the first electrode layer 112 to have a predetermined thickness. Preferably, it may be formed to a thickness of 65 mu m to 95 mu m. The heat dissipation layer 114 is formed to dissipate heat generated in the light emitting layer 115 to the outside and may be connected to a heat sink (not shown) provided under the substrate 111.

The light emitting layer 115 may be formed on the heat dissipation layer 114. The light emitting layer 115 may be one of a colored LED chip and a light emitting chip including a UV chip.

The light emitting device may have a vertical structure, a horizontal structure, or a flip chip structure according to the layout structure of the light emitting chip mounted on the substrate 111. At this time, the light emitting device may be mounted by a method such as wire bonding or flip chip bonding using a wire 118 according to the structure of the light emitting chip.

The light emitting device may mount at least one or more light emitting chips on the substrate 111. That is, the light emitting chip is only an example according to the embodiment, and the light emitting chip may be further disposed according to a desired purpose and a design change. Accordingly, the light emitting device can be implemented as a single chip or a multi-chip structure depending on the number of the light emitting chips.

A light emitting device for converting electrical energy into light may be mounted on the light emitting chip. At this time, the light emitting device includes an active layer of a semiconductor material interposed between two opposing doping layers. When a bias is applied to both ends of the two doped layers, holes and electrons are injected into the active layer and then recombined to generate light. Light generated in the active layer is emitted in all directions and emitted through the exposed surface to the outside of the light emitting device.

The light emitting chip may be a blue LED chip or an ultraviolet (UV) chip. In addition, the light emitting chip may be configured as a package in which one or more of a red LED, a green LED, a blue LED, a yellow green LED, and a white LED are combined. At this time, the light emitting chip may include all nitride semiconductor light emitting devices including a pn or npn junction structure.

In addition, although the light emitting chip composed of the light emitting layer 115 is illustrated as being disposed on the first electrode layer 113 in FIG. 2, the light emitting chip may be disposed on the substrate 111. At this time, when the light emitting chip is disposed on the substrate 111, an insulating layer may be formed between the substrate 111 and the light emitting chip.

The phosphor layer 116 and the electrode pad 117 may be disposed on the light emitting layer 115. At this time, the phosphor layer 116 may include at least one kind of phosphor.

The phosphor plays a role of exciting the light emitted from the light emitting layer 115. For example, the phosphor may include at least one of a silicate series, a sulfide series, a YAG series, a TAG series, and a nitride series.

The phosphor may include at least one of yellow, red, green and blue phosphors emitting yellow, red, green and blue light, but the type of the phosphor is not limited.

The light emitting device emits light of different wavelengths in response to the wavelength of light incident on the phosphor depending on the hue of the phosphor. Therefore, light of a required wavelength or color can be obtained according to the combination of the color of the light emitting layer 115 and the color of the phosphor.

On the other hand, CaS: Eu may be used as a typical sulfide-based inorganic phosphor to emit deep red light. At least one of SrS: Eu and MgS: Eu of the sulfide series may be used as the orange phosphor. As the green phosphor, sulfide-based SrGa2S4 and Eu2 + can be used.

The phosphor may include different kinds and amounts depending on the light emitting layer 1115. For example, when the light emitting layer 115 emits white light, the green and red phosphors may be included in the phosphor layer 116. Further, when the light emitting layer 115 emits blue light, the phosphor layer 116 may include green, yellow, and red phosphors. As described above, the type and amount of the phosphor included in the phosphor layer 116 may vary depending on the type of the light emitting layer 115.

The electrode pad 117 may be formed on a predetermined region of the light emitting layer 115 in a direction in which the second electrode layer 113 is disposed. The electrode pad 117 may be electrically connected to the second electrode layer 113 through the wire 118. At this time, if the light emitting chip of the light emitting layer 115 has a horizontal or vertical structure, it is electrically connected to the second electrode layer 113 through the wire 118.

The light emitting device is bonded to the electrode pad 117 and the second electrode layer 113 using a single wire 118 because a vertical type light emitting chip is illustrated. As another example, when the light emitting chip is of the horizontal type, two wires may be used, and in the case of the flip chip method, the wire may not be used.

Meanwhile, a protection element such as a zener diode may be mounted on the first electrode layer 112 to protect the light emitting chip.

The cover 119 may have a hemispherical shape having an opening at a lower portion to surround the light emitting layer 115. The cover 119 may be formed of a transparent polymer or glass capable of transmitting light emitted from the light emitting layer 115.

Here, the polymer may be at least one selected from the group consisting of polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic resin, polystyrene (PS) Polymethyl methacrylate (PMMA), and the like. In particular, when the cover 119 is made of the polymer material, it may be made of polycarbonate (PC) when heat resistance and chemical resistance are required.

When the phosphor layer 116 is not disposed in the light emitting device, the cover 119 may be formed by mixing a plastic material with phosphors and a metal injection molding method . ≪ / RTI >

The cover 119 may not only transmit light but also diffuse light. For example, the cover 119 may be composed of a transparent diffuser plate or a transparent substrate containing a diffusing agent. The diffusing agent may be at least one selected from the group consisting of silicon oxide (SiO2), titanium oxide (TiO2), zinc oxide (ZnO), barium sulfate (BaSO4), calcium carbonate (CaSO4), magnesium carbonate (MgCO3) ), Synthetic silica, glass beads, and diamond. However, the present invention is not limited thereto. In addition, the particle size of the diffusing agent may be selected to be a size suitable for light diffusion, and may have a diameter of, for example, 5 to 7 μm.

Subsequently, a mixing space is formed in the inner space of the cover 119. The mixing space is a space in which light emitted from the light emitting layer 115 is mixed.

The cover 119 may further include at least one of an antifoaming agent, an additive, and a curing agent.

The defoaming agent can ensure reliability by removing bubbles in the cover 119. Particularly, when the cover 119 is manufactured using a metal injection molding method, the problem of bubbles can be solved. Examples of the antifoaming agent include, but are not limited to, at least one of octanol, cyclohexanol, ethylene glycol, and various surfactants.

The curing agent serves to cure the cover 119.

The additive serves to uniformly disperse the phosphor in the cover 119.

Accordingly, the cover 119 can change the wavelength of the light emitted from the light emitting layer 115. Accordingly, the cover 119 is applied to a light source such as various lighting devices, a backlight unit, a light emitting device, and a display device, and is used to generate light having various wavelengths or to improve the CRI of the light source And the like.

The protective layer 120 may be formed on the substrate 111 and the first and second electrode layers 112 and 113 in the cover 119 to sufficiently cover the side surfaces of the heat dissipation layer 114. [ have.

The protective layer 120 may be formed to have the same height as the heat dissipation layer 114 and may have a height enough to cover at least 80% of the side surface of the heat dissipation layer 114. If the protective layer 120 is formed to have a higher height than the heat dissipation layer 114, it may interfere with light emission. If the protective layer 120 is formed to a very low level, The inhibitory effect may be lowered.

The protective layer 120 may be formed using a resin or an inorganic material. At this time, the resin material is made of a resin having a high reflectance so as not to cause a decrease in light flux, and a resin having a low gas permeability is used to suppress the occurrence of ion migration from the heat dissipation layer (114).

The heat dissipation layer 114 is formed to dissipate the heat generated in the light emitting layer 115 to the outside. Tungsten (W) is used for improving heat dissipation. However, molybdenum (Mo) have. However, the molybdenum (Mo) has a problem of causing ion migration to an electric field and distilled water, and there is a problem that the oxide film peels off at a high temperature. In order to solve this problem, in this embodiment, the side surface of the heat dissipation layer 114 is filled with the protection layer 120 so that the heat dissipation layer 114 is not exposed to the outside.

Therefore, the light emitting device covers the side surface of the heat dissipation layer 114 exposed to the outside with the protective layer 120 to suppress the occurrence of ion migration and oxide film peeling, thereby improving the reliability and lifetime of the product .

Second Embodiment

3 is a cross-sectional view of the light emitting device according to the second embodiment.

The second embodiment 200 of the light emitting device includes a substrate 211, first and second electrode layers 212 and 213, a heat dissipation layer 214, a light emitting layer 215, a phosphor layer 216 An electrode pad 217, a wire 218, a cover 219, a barrier 220,

In the second embodiment 200 of the light emitting device, the substrate 211, the first and second electrode layers 212 and 213, the heat dissipation layer 214, the light emitting layer 215, the phosphor layer 216, The electrode pad 217, the wire 218 and the cover 219 are formed on the substrate 111, the first and second electrode layers 112 and 113 of the first embodiment 100 of the light emitting device, The light emitting layer 115, the phosphor layer 116, the electrode pad 117, the wire 118, and the cover 119 are the same as those of the light emitting layer 114, the light emitting layer 115,

In the second embodiment of the light emitting device 200, the barrier rib 220 is formed on the substrate 211 outside the first electrode layer 212, and the barrier rib 220 and the heat- The protective layer 230 is formed on the first electrode layer 212 between the first electrode layer 212 and the second electrode layer 214 so as to sufficiently cover the side surface of the heat dissipation layer 214. [

The barrier ribs 220 may be formed in the cover 219 and may be formed around the periphery of the first electrode layer 212. The barrier rib 220 may be disposed between the first electrode layer 212 and the second electrode layer 213 at a portion where the second electrode layer 213 is disposed. Accordingly, the barrier rib 220 is disposed below the wire 218 connected between the electrode pad 217 and the second electrode layer 213.

The partition 220 may have the same height as the heat dissipation layer 214. In addition, the heat dissipation layer 214 may be formed to be slightly higher than the heat dissipation layer 214 without completely covering the side surface of the light emitting layer 115.

The shape of the barrier ribs 220 may be hemispherical or semi-elliptical as shown in FIG. 3, or may be formed in a semicircle, a quadrangle, or a quadrilateral having a chamfer at the upper corner.

The passivation layer 230 is formed on the first electrode layer 212 between the heat dissipation layer 214 and the barrier rib 220 and completely covers the side surface of the heat dissipation layer 214.

The protective layer 230 may be formed to have the same height as the heat dissipation layer 214 and may have a height enough to cover 80% or more of the side surface of the heat dissipation layer 214.

The protective layer 230 may be formed using a resin or an inorganic material. The resin used as the material of the protective layer 230 is made of a resin having a high reflectance so as not to cause a decrease in luminous flux and an ion migration occurs from the heat dissipation layer 214 using a resin having low gas permeability .

The side surfaces of the heat dissipation layer 214 are buried with the passivation layer 220 so that the phenomenon of ion migration and peeling of the oxide layer caused by the heat dissipation layer 214 being exposed to the outside can be suppressed, The reliability and life of the product can be improved.

The barrier rib 220 may be disposed under the wire 218 connected between the electrode pad 217 and the second electrode layer 213 so that the protective layer 230 does not contact the wire 218 The stress of the wire 218 can be reduced.

The light emitting device of the present invention thus configured can overcome the technical problem of the present invention by covering the side surface of the heat radiation layer exposed to the outside with a protective layer.

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 embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

The light emitting device according to the embodiment can be used for a lighting device, a backlight unit for a display, and the like.

100: First Embodiment of Light Emitting Device
111: substrate 112: first electrode layer
113: second electrode layer 114: heat dissipation layer
115: luminescent layer 116: phosphor layer
117: electrode pad 118: wire
119: Cover 120: Protective layer
200: Second Embodiment of Light Emitting Device
211: substrate 212: first electrode layer
213: second electrode layer 214: heat dissipating layer
215: light emitting layer 216: phosphor layer
217: electrode pad 218: wire
219: Cover 220:
230: Protective layer

Claims (17)

Board;
First and second electrode layers spaced apart from each other on the substrate;
A heat dissipation layer disposed on the first electrode layer;
A first conductivity type semiconductor layer disposed on the heat dissipation layer, a second conductivity type semiconductor layer, an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, A light emitting element including a first electrode pad electrically connected to the first electrode pad and a second electrode pad electrically connected to the second conductive semiconductor layer;
A phosphor layer disposed on the light emitting element;
A wire disposed between the second electrode pad and the second electrode layer;
A cover disposed on the substrate and covering the first electrode layer and the second electrode layer; And
And a protective layer disposed on the substrate and surrounding the heat dissipation layer,
Wherein the first electrode pad is electrically connected to the heat dissipation layer and the first electrode layer,
The second electrode pad is electrically connected to the wire and the second electrode layer,
The height between the upper surface of the substrate and the upper surface of the heat dissipation layer is equal to the height of the upper surface of the substrate and the upper surface of the protective layer,
Wherein the protective layer surrounds a part of the wire. The method according to claim 1,
And a barrier disposed around the protective layer. 3. The method according to claim 1 or 2,
Wherein the protective layer is formed of a resin or an inorganic material. 3. The method of claim 2,
And the barrier rib is disposed between the first electrode layer and the second electrode layer. 3. The method according to claim 1 or 2,
Wherein the heat dissipation layer is formed of any one of metals including tungsten (W) and molybdenum (Mo). 3. The method according to claim 1 or 2,
Wherein the heat dissipation layer has a thickness of 65 占 퐉 to 95 占 퐉. 3. The method of claim 2,
And the wire is disposed on the partition wall. 5. The method of claim 4,
And the protective layer is disposed inside the partition wall. 3. The method of claim 2,
Wherein the barrier ribs have any one of a hemispherical shape, a semi-elliptical shape, a semicircular shape, a quadrangle, and a quadrangle in which a chamfer is formed in an upper corner. 3. The method of claim 2,
Wherein the barrier rib is formed of an insulating material. 3. The method according to claim 1 or 2,
Wherein the cover is made of a polymer or glass of a light transmitting material. delete 3. The method according to claim 1 or 2,
Wherein at least one kind of phosphor is added to the phosphor layer. 3. The method according to claim 1 or 2,
Wherein the substrate is made of any one material selected from the group consisting of ceramic, polymer, resin, silicon, and metal. 9. The method of claim 8,
Wherein the first height between the upper surface of the substrate and the upper surface of the protective layer is equal to the height of the barrier rib. 9. The method of claim 8,
Wherein the first height between the upper surface of the substrate and the upper surface of the protective layer is smaller than the height of the partition. The method according to claim 1,
And the protective layer contacts the inner surface of the cover.

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