KR20120131607A - light emitting device package and lighting system including the same - Google Patents

Abstract

PURPOSE: A light emitting device package and a lighting system including the same are provided to improve light reflection efficiency by forming a reflection layer on a lead frame. CONSTITUTION: A body(110) includes a cavity. A first lead frame(121) and a second lead frame(122) are installed in the body. A light emitting device(150) is electrically connected to the first lead frame and the second lead frame. A reflection layer is formed on the first lead frame and the second lead frame. A protection layer is formed on the reflection layer. A fluorescent substance(180) changes the wavelength of light emitted from the light emitting device.

Description

Light emitting device package and lighting system including the same

Embodiments are directed to a light emitting device package having a protective layer formed on a reflective layer on a lead frame and an illumination system 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 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 light extraction efficiency can be improved by forming a reflective layer on the lead frame used as an electrode in the light emitting device package.

The embodiment aims to improve the light extraction efficiency of the light emitting device package.

Embodiments include at least a pair of lead frames; A reflective layer on the lead frame; A protective layer on the reflective layer; A light emitting device electrically connected to the lead frame; And a resin layer covering the light emitting device, wherein the protective layer is selected from the group consisting of SiO ₂ , TiO _2, and Al ₂ O ₃ , and includes a first layer and a second layer made of different materials. Provide a device package.

The protective layer may be repeatedly arranged at least twice of the first layer and the second layer.

The protective layer is selected from the group consisting of SiO ₂ , TiO ₂ and Al ₂ O ₃ , and may include a third layer made of a material different from the first layer and the second layer.

The protective layer may be repeatedly arranged at least twice of the first layer, the second layer, and the third layer.

The thickness of each layer in the protective layer may be d = λ / 4n.

λ may be the wavelength of visible or ultraviolet light.

The resin layer may be made of epoxy resin.

The reflective layer may be an alloy containing silver or an alloy including an aluminum laminate.

Another embodiment provides an illumination system including the light emitting device package described above.

In the light emitting device package according to the embodiment, a reflective layer is formed on the lead frame to increase light extraction efficiency, and the protective layer on the reflective layer may prevent the reflective layer from discoloring by reacting with the outside.

1 is a cross-sectional view of an embodiment of a light emitting device package,
2 is a view showing 'A' of FIG. 1 in detail;
3A is a view showing a first embodiment of the configuration of the protective layer of FIG. 2,
3B is a view showing a second embodiment of the configuration of the protective layer of FIG.
4 is a view showing a third embodiment of the structure of the protective layer of FIG.
5 is a view showing the optical path difference in the protective layer,
6 is a view showing the thickness of the protective layer composed of TiO ₂ and Al ₂ O ₃ ,
7 to 9 are views showing another embodiment of the light emitting device package,
10 is an exploded perspective view of an embodiment of a lighting device including a light emitting device package according to the embodiments,
11 is a diagram illustrating an example of a display device including a light emitting device package according to embodiments.

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 above or below each layer will be described with reference to the drawings.

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

1 is a cross-sectional view of an embodiment of a light emitting device package.

The light emitting device package according to the embodiment includes a body 110 including a cavity, a first lead frame 121 and a second lead frame 122 installed on the body 110, and the body 110. And a light emitting device 150 according to an exemplary embodiment installed on the first lead frame 121 and the second lead frame 122, and a molding unit 170 formed in the cavity.

The body 110 may include a silicon material, a synthetic resin material, or a metal material. When the body 110 is made of a conductive material such as a metal material, although not shown, an insulating layer is coated on the surface of the body 110 to prevent an electrical short between the first and second lead frames 121 and 122. Can be.

The first lead frame 121 and the second lead frame 122 are electrically separated from each other, and supply a current to the light emitting device 150. In addition, the first lead frame 121 and the second lead frame 122 may increase light efficiency by reflecting the light generated by the light emitting device 150, and heat generated by the light emitting device 150. Can be discharged to the outside.

The light emitting device 150 may be installed on the body 110 or may be installed on the first lead frame 121 or the second lead frame 122. In this embodiment, the first lead frame 121 and the light emitting device 150 are directly energized, and the second lead frame 122 and the light emitting device 150 are connected through a wire 160. The light emitting device 150 may be connected to the lead frames 121 and 122 in addition to the wire bonding method by a flip chip method or a die bonding method.

The molding part 170 may surround and protect the light emitting device 150. In addition, the molding unit 170 may include a phosphor 180 to change the wavelength of light emitted from the light emitting device 150. The molding part 170 may be formed to cover at least the light emitting device 150 and the wire 160.

In addition, the light of the first wavelength region emitted from the light emitting device 150 is excited by the phosphor 180 and converted into the light of the second wavelength region, and the light of the second wavelength region is a lens (not shown). The light path may be changed while passing through.

FIG. 2 is a diagram illustrating 'A' of FIG. 1 in detail.

The reflective layer 130 and the protective layer 140 are sequentially formed on the first lead frame 121. That is, the light emitted from the light emitting device may proceed to the lower part of the light emitting device or may be reflected at the cavity sidewall formed in the body 110 in FIG. 1 and may proceed to the lower part of the light emitting device. By reflecting the light extraction efficiency of the package can be improved.

The reflective layer 130 is made of a material having excellent reflectance, and as an example, silver (Ag) may be coated on the first and second lead frames 121 and 122. The reflective layer 130 may be made of an alloy including silver (Ag) or an alloy including aluminum (Al).

In addition, a protective layer 140 may be formed on the reflective layer 130. The reflective layer 130 may react with the phosphor 180 or the filler (not shown) in the molding unit 170, or may be discolored by being exposed to light emitted from the light emitting device 150.

When the reflective layer 130 is changed from black to a similar dark color, the light reflection efficiency of the reflective layer 130 may be lowered, thereby lowering the light extraction efficiency of the light emitting device package.

In the present exemplary embodiment, the protective layer 140 may be formed on the reflective layer 130 to prevent discoloration of the reflective layer 130. The reflective layer 130 may be optically transparent and may include a plurality of layers.

The table below shows the composition and reflectance of the reflective layer 130 and the protective layer 140.

Reflective layer Protective layer reflectivity(%) Example 1 Ag SiO ₂ / TiO ₂ 93.7 Example 2 Ag SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ 94.8 Example 3 Ag SiO2 / TiO2 / SiO2 / TiO2 / SiO ₂ / TiO ₂ 94.9 Example 4 Ag SiO ₂ / Al ₂ O ₃ 95.4 Example 5 Ag SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ 88.0 Example 6 Ag SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ 87.9 Example 7 Ag TiO ₂ / Al ₂ O ₃ 94.4 Example 8 Ag TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ 96.8 Example 9 Ag TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ 88.6

In the embodiment shown in Table 1, silver (Ag) is used as the reflective layer 130, and at least two materials selected from the group consisting of SiO ₂ , TiO ₂ and Al ₂ O ₃ are used as the protective layer 140. Use layer. When the protective layer 140 is formed of a plurality of layers, the effect of preventing foreign matter from penetrating into the reflective layer 130 may be greater.

The reflective layer 130 may be made of aluminum (Al) or an alloy of silver and aluminum in addition to silver (Ag).

In addition, the selected materials may be stacked on the reflective layer 130 once, alternately stacked twice, or alternately stacked three or more times. The protective layer 140 may be formed by forming three layers of SiO ₂ , TiO _2, and Al ₂ O ₃ , respectively, or these three layers may be alternately arranged at least twice.

FIG. 3A is a view showing a first embodiment of the configuration of the protective layer of FIG. 2, wherein two layers A / 142 and B / 144 made of different materials are repeatedly disposed twice to form the protective layer 140. It is coming true. For example, SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ , SiO _{2 ,} / TiO ₂ / SiO ₂ / TiO ₂ , TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ .

3B illustrates a second embodiment of the protective layer of FIG. 2, wherein two layers A / 142 and B / 144 made of different materials are repeatedly formed three times to form the protective layer 140. . For example, SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ / SiO ₂ / Al ₂ O ₃ , SiO _{2 ,} / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ , TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ / TiO ₂ / Al ₂ O ₃ .

FIG. 4 is a view showing a third embodiment of the configuration of the protective layer of FIG. 2, wherein three layers A / 142, B / 144, and C / 146 made of different materials are repeatedly disposed two times. 140.

The protective layer 140 may prevent discoloration of the reflective layer 130. Light emitted from the light emitting device 150 may pass through the protective layer 140 to reach the reflective layer 130. Light reflected from the reflective layer 130 may pass through the protective layer 140 again and pass through the resin layer 170 to be emitted to the outside.

That is, since the light is incident from the outside and the light reflected from the reflective layer 130 proceeds again, the protective layer 140 should minimize the extinction interference due to the difference in the optical path between the incident light and the reflected light. do.

In order to minimize the optical path difference between the incident light and the reflected light, the thickness d = λ / 4n of the protective layer 140 may be satisfied, where λ is a wavelength of light incident on each layer, and n is Is an integer.

In embodiments, since the protective layer 140 is formed of a plurality of layers, when the thickness of each layer satisfies the above-described equation, the light path difference may be minimized to minimize the extinction interference of light. In this case, λ may be a wavelength of light emitted from the light emitting device 150 and entering each layer in the protective layer 140, and may be, for example, a wavelength of visible light or ultraviolet light.

5 is a view showing a light path difference in a protective layer.

When the refractive index of any layer in the protective layer is n and the thickness of the arbitrary layer is d, the light L ₁ reflected from the surface of the layer and the light L ₂ incident on the layer and then traveling outside again The furnace may be minimized when the thickness of the protective layer 140 satisfies the above-described formula.

6 is a view showing the thickness of a protective layer composed of TiO ₂ and Al ₂ O ₃ .

In FIG. 6, two layers 142 and 144 made of TiO ₂ and Al ₂ O ₃ are stacked twice on the reflective layer 130 to form a protective layer 140. At this time, when the thickness of each layer satisfies the above-described formula, the entire protective layer 140 may not reduce the light efficiency of the light emitting device package.

7 to 9 are views showing another embodiment of the light emitting device package.

The embodiment shown in FIG. 7 is similar to the embodiment of FIG. 1, but the phosphor 280 is conformally coated in a separate layer from the molding part 270. In this structure, the phosphor 280 is uniformly distributed, so that the wavelength of the light emitted from the light emitting device 250 may be converted in the entire region where the light of the light emitting device package 200 is emitted.

Although the embodiment shown in FIG. 8 is similar to the embodiment of FIG. 1, the body 310 of the light emitting device package 300 does not form a cavity. In addition, the phosphor 380 is conformally coated around the light emitting device 350, and the molding part 370 forms a lens structure to adjust the light directing angle.

In FIG. 9, in the embodiment shown in FIG. 1, three layers 142, 144, and 146 form a protective layer. In the light emitting device package according to the embodiments described above, a reflective layer is formed on the surface of the package body or the lead frame to increase light reflection efficiency, and a protective layer is formed on the reflective layer to prevent the reflective layer from discoloring by reacting with light or other materials. can do.

10 is an exploded perspective view of an embodiment of a lighting device including a light emitting device package according to the embodiments.

The lighting apparatus according to the embodiment includes a light source 600 for projecting light, a housing 400 in which the light source 600 is embedded, a heat dissipation part 500 for dissipating heat from the light source 600, and the light source 600. And a holder 700 for coupling the heat dissipation part 500 to the housing 400.

The housing 400 includes a socket coupling part 410 coupled to an electric socket and a body part 420 connected to the socket coupling part 410 and having a light source 600 embedded therein. One air flow port 430 may be formed in the body portion 420.

A plurality of air flow port 430 is provided on the body portion 420 of the housing 400, wherein the air flow port 430 is composed of one air flow port, or a plurality of flow ports as shown in the radial arrangement Various other arrangements are also possible.

The light source 600 includes a plurality of light emitting device packages 650 on the circuit board 610. Here, the circuit board 610 may be inserted into the opening of the housing 400, and may be made of a material having a high thermal conductivity to transmit heat to the heat dissipating unit 500, as described later.

A holder 700 is provided below the light source, and the holder 700 may include a frame and another air flow port. In addition, although not shown, an optical member may be provided under the light source 100 to diffuse, scatter, or converge light projected from the light emitting device package 150 of the light source 100.

In the above-described lighting apparatus, a reflective layer is formed on the surface of the package body or the lead frame of the light emitting device package to improve light reflection efficiency, and a protective layer is formed on the reflective layer to prevent the reflective layer from discoloring in response to light or other materials. The light efficiency of the lighting device can be improved.

11 illustrates a backlight including a light emitting device package according to embodiments.

As shown, the display device 800 according to the present exemplary embodiment is disposed in front of the light source modules 830 and 835, the reflector 820 on the bottom cover 810, and the reflector 820. The light guide plate 840 for guiding light emitted from the front of the display device, the first prism sheet 850 and the second prism sheet 860 disposed in front of the light guide plate 840, and the second prism sheet ( And a color filter 880 disposed in front of the panel 870 disposed in front of the panel 870.

The light source module includes a light emitting device package 835 on the circuit board 830. Here, the PCB 830 may be used as the circuit board 830, and the light emitting device package 835 is as described above.

The bottom cover 810 may accommodate components in the display device 800. The reflective plate 820 may be provided as a separate component as shown in the drawing, or may be disposed on the rear surface of the light guide plate 840, or The bottom cover 810 may be provided in the form of a coating with a highly reflective material.

Here, the reflection plate 820 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and polyethylene terephthalate (PET) can be used.

The light guide plate 840 scatters light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the LCD. Accordingly, the light guide plate 840 is made of a material having a good refractive index and transmittance. The light guide plate 840 may be formed of poly methylmethacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). The light guide plate 83 may be omitted from the backlight unit so that air acts as an optical waveguide.

In addition, the light guide plate 840 may be omitted, and may be an air guide method in which the light reflected from the reflector 820 proceeds straight to the panel direction.

The first prism sheet 850 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 the second prism sheet 860, the direction of the floor and the valley of one surface of the support film may be perpendicular to the direction of the floor and the valley of one surface of the support film in the first prism sheet 850. This is to evenly distribute the light transmitted from the light source module and the reflective sheet in all directions of the panel 870.

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.

Although not shown, a diffusion sheet may be disposed between the light guide plate 840 and the first prism sheet 850. The diffusion sheet may be made of polyester and polycarbonate-based materials, and may maximize the light projection angle through refraction and scattering of light incident from the backlight unit.

The diffusion sheet includes a support layer including a light diffusing agent, a first layer and a second layer formed on a light exiting surface (first prism sheet direction) and a light incident surface (reflective sheet direction) and not including a light diffusing agent. It may include.

The support layer is 0.1 to 10 parts by weight of a siloxane light diffusing agent having an average particle diameter of 1 to 10 micrometers with respect to 100 parts by weight of a resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer are mixed; 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 as 0.01 to 1 part by weight of the ultraviolet absorber and 0.001 to 10 parts by weight of the antistatic agent based on 100 parts by weight of the methyl methacrylate-styrene copolymer resin.

The thickness of the support layer in the diffusion sheet is 100 ~ 10000 micrometers, the thickness of each layer may be 10 ~ 1000 micrometers.

In the present embodiment, the diffusion sheet, the first prism sheet 850 and the second prism sheet 860 form an optical sheet, and the optical sheet is made of another combination, for example, a micro lens array or a diffusion sheet and a micro Combination of a lens array or a combination of one prism sheet and a micro lens array.

The liquid crystal display panel (Liquid Crystal Display) may be disposed on the panel 870, in addition to the liquid crystal display panel 860 may be provided with other types of display devices that require a light source.

The panel 870 is a state in which the liquid crystal is located between the glass body and the polarizing plate is placed on both glass bodies in order to use the 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.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

The front surface of the panel 870 is provided with a color filter 880 to transmit the light projected from the panel 870, only the red, green and blue light for each pixel can represent an image.

In the above-described backlight unit, a reflective layer is formed on the surface of the package body or the lead frame of the light emitting device package to improve light reflection efficiency, and a protective layer is formed on the reflective layer to prevent the reflective layer from discoloring by reacting with light or other materials. The light efficiency of the backlight unit may be improved.

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.

100, 200, 300: light emitting device package
110, 210, 310: Package Body
121, 221, and 321: first lead frame
122, 222, 322: second lead frame
130: reflective layer 140: protective layer
150: light emitting element 160: wire
170: molding part 180: phosphor
400: housing
500: radiator 600: light source
700: holder 800: display device
810: bottom cover 820: reflector
830: circuit board module 840: light guide plate
850, 860: first and second prism sheet 870: panel
880 color filter

Claims (9)

At least one pair of lead frames;
A reflective layer on the lead frame;
A protective layer on the reflective layer;
A light emitting device electrically connected to the lead frame; And
A resin layer covering the light emitting element;
The protective layer is selected from the group consisting of SiO ₂ , TiO ₂ and Al ₂ O ₃ , the light emitting device package comprising a first layer and a second layer made of different materials. The method of claim 1, wherein the protective layer,
The light emitting device package of the first layer and the second layer are alternately arranged at least twice. The method of claim 1, wherein the protective layer,
A light emitting device package comprising: a third layer selected from the group consisting of SiO ₂ , TiO _2, and Al ₂ O ₃ , and comprising a material different from the first and second layers. The method of claim 1, wherein the protective layer,
And the first layer, the second layer, and the third layer are alternately arranged at least twice. The method according to any one of claims 1 to 4,
A light emitting device package in which the thickness of each layer in the protective layer is d = λ / 4n, wherein λ is a wavelength of light incident on each of the layers, and n is an integer. The method according to claim 5, wherein λ is,
Light emitting device package having a wavelength of visible light or ultraviolet light. The method of claim 1,
The resin layer is a light emitting device package made of epoxy resin. The method of claim 1, wherein the reflective layer,
A light emitting device package which is an alloy containing silver or an alloy containing an aluminum laminate. The lighting system comprising the light emitting device package of any one of claims 1 to 4.

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