KR20140092034A - Light emitting device and lighting communication device including the same - Google Patents

Abstract

An embodiment of the present invention provides a light emitting device comprising a first lead frame and a second lead frame which are disposed on a substrate and electrically separated from each other; a light emitting device which is electrically connected to the first lead frame and the second lead frame to emit light in a first wavelength region; a phosphor layer which is disposed on the light emitting device; and a lens which are disposed on the light emitting device and the first lead frame and the second lead frame, and corresponds to the light emitting device, wherein the phosphor layer includes a second phosphor excited by the light in the first wavelength region to emit light in a second wavelength region, and a third phosphor excited by the light in the first wavelength region to emit light in a third wavelength region. The third wavelength is longer than the second wavelength and the size of the second phosphor is larger than the size of the third phosphor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device,

Embodiments relate to a light emitting device package and an illumination communication device including the same.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

In the light emitting device, electrons injected through the first conductive type semiconductor layer and holes injected through the second conductive type semiconductor layer meet each other to emit light having energy determined by a specific energy band of the material forming the active layer (light emitting layer) do. In the light emitting device package, the phosphor is excited by the light emitted from the light emitting device to emit light in a longer wavelength range than the light emitted from the active layer.

1 is a view showing a conventional light emitting device package.

A conventional light emitting device package 100 includes a package body 110 on which a first lead frame 121 and a second lead frame 122 are disposed and a conductive adhesive layer (not shown) is formed on the first lead frame 121 The light emitting element 140 is disposed.

The light emitting device 140 is electrically connected to the first lead frame 121 through the conductive adhesive layer and electrically connected to the second lead frame 122 through the wire 150.

Cavity is formed in the package body 110 and the light emitting device 140 is disposed on the bottom surface of the cavity and the resin layer 160 is filled in the cavity. And the light of the second wavelength range may be emitted by exciting the phosphor 165 by the light of the first wavelength range emitted from the light emitting device 140.

However, the conventional light emitting device package has the following problems.

In the light emitting device package, light emitted from the light emitting device is excited by the phosphor and is emitted as light in a different wavelength region, so that it takes time for the phosphor to be excited and emit light. Therefore, although the above-described light emitting device package can be used for a lighting apparatus, it is difficult to use it in an illumination communication apparatus or the like.

 Particularly, in the case of a light emitting device package in which a yellow region is higher in blue than a blue region in a spectrum, since the size of the phosphor is small, scattering of light by the phosphor easily occurs, Is inputted to the light emitting element, light is emitted from the light emitting element, and the phosphor is excited, so that it takes much time for the light to be generated again.

Embodiments provide a light emitting device package that can be used for an illumination communication device by shortening the time until light is emitted after an electrical signal is input.

An embodiment includes a first lead frame and a second lead frame disposed on a substrate and electrically separated from each other; A light emitting element electrically connected to the first lead frame and the second lead frame to emit light in a first wavelength range; A phosphor layer disposed on the light emitting element; And a lens disposed on the first lead frame and the second lead frame and corresponding to the light emitting element, wherein the phosphor layer is excited by light in the first wavelength region, And a third phosphor that emits light in a third wavelength range by being excited by light in the first wavelength range, wherein the third wavelength is longer than the second wavelength, and the third wavelength is longer than the second wavelength, 2 phosphor is larger than the size of the third phosphor.

The size of the first phosphor is 10 to 13 micrometers, and the first phosphor may be a yellow phosphor.

The size of the second phosphor may be 8 to 10 micrometers, and the second phosphor may be a red phosphor.

The phosphor layer may cover the upper surface of the light emitting device. The phosphor layer surrounds at least a part of the side surface of the light emitting device and surrounds the side surface of the light emitting device. Layer may cover the active layer of the light emitting device.

The substrate may have a flat first surface on which the light emitting device is disposed.

Another embodiment provides an illumination communication device in which the above-described light emitting element is disposed.

The light emitting device package according to the present embodiment uses a relatively large (yellow) phosphor and emits light having a large CCT deviation due to a relatively small amount of color mixture due to scattering of light. However, since light scattering is small, Which is shorter than that of Comparative Examples 1 and 2, which can be advantageous for an illumination communication apparatus.

1 is a view illustrating a conventional light emitting device package,
2 is a view illustrating a light emitting device package according to an embodiment,
FIG. 3 is a view illustrating a light emitting device of the light emitting device package of FIG. 2,
4A to 4C are views illustrating embodiments of the phosphor layer of the light emitting device package of FIG. 2,
5 is a view showing the distribution of the phosphor in the phosphor layer,
FIG. 6 is a view comparing the light emission speed of the light emitting device package of FIG. 2 with other devices,
7A and 7B are views showing the spectrum of the package of the light emitting device according to the embodiment and the CCT-to-orientation angle, respectively,
FIGS. 8A and 8B and FIGS. 9A and 9B are views showing a spectrum of the light emitting device package according to Comparative Examples 1 and 2 and a CCT-oriented angle, respectively,
10 is a diagram showing an embodiment of an illumination communication device in which a light emitting device package is disposed.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

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.

2 is a view illustrating a light emitting device package according to an embodiment.

The light emitting device package 200 according to the embodiment includes a substrate 210, a first lead frame 221 and a second lead frame 222 disposed on the substrate, And a light emitting element 240 fixed through a conductive adhesive layer (not shown).

The substrate 210 may be made of a ceramic material having excellent thermal conductivity. For example, the substrate 210 may be a square sapphire (Al ₂ O ₃ ) having a length of 3.4 mm and a length of 3.4 mm. The first lead frame 221 and the second The lead frame 222 may be made of a conductive material such as copper, and may be formed by plating gold (Au), for example. The first lead frame 221 and the second lead frame 222 may reflect light emitted from the light emitting device 240. [ In addition, the substrate 210 may be flat both of the first surface on which the light emitting device 240 is disposed and the second surface opposite to the first surface.

The light emitting device 240 may include a light emitting diode or the like, and may be electrically connected to the second lead frame 222 through the wire 250. The wire 250 may be made of a conductive material and may be made of gold (Au) having a diameter of about 0.8 to 1.6 millimeters. If the wire 250 is too thin, it may be cut by an external force. If the wire 250 is too thick, the material cost may be reduced and the light emitted from the light emitting device 240 may be an obstacle to the progress. In this embodiment, a vertical light emitting device is disposed, but a horizontal light emitting device or a flip chip type light emitting device may be disposed.

The phosphor layer 270 is disposed on the light emitting device 240 in a conformal coating manner to have a constant thickness and corresponds to the light emitting device 240 and surrounds the light emitting device 240, . The lens 280 may be of a dome type and may be arranged in a different shape to adjust the light output angle of the light emitting device package 200.

The first pad 231 and the second pad 232 are connected to the first lead frame 221 and the second lead frame 222. The first and second pads 231, May be disposed through the substrate 210 and the first pad 231 and the second pad 232 may function as a first electrode and a second electrode, respectively. The first to third pads 231, 232, and 235 are formed of a material having a high thermal conductivity and disposed under the substrate 210 to fix the light emitting device package 200 to the housing, Pathway.

3 is a view illustrating a light emitting device of the light emitting device package of FIG.

The light emitting device 240 according to the present embodiment is a vertical light emitting device and the light emitting structure 242 includes a first conductivity type semiconductor layer 242a, a second conductivity type semiconductor layer 242c, and a first conductivity type semiconductor layer And an active layer 242b disposed between the first conductive semiconductor layer 242a and the second conductive semiconductor layer 242c.

The first conductive semiconductor layer 242a may be formed of a semiconductor compound. The first conductive semiconductor layer 242a may be formed of a compound semiconductor such as a group III-V element, a group II-VI element, or the like, and may be doped with a first conductive type dopant. When the first conductive semiconductor layer 242a is an N-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, and Te as an N-type dopant.

The first conductive semiconductor layer 242a includes a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) can do. The first conductive semiconductor layer 242a may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

The surface of the light emitting structure 242, that is, the surface of the first conductivity type semiconductor layer 242a, may have irregularities to increase the light extraction effect.

The first electrode 244 may be formed on the surface of the first conductive semiconductor layer 242a and the first electrode 244 may be formed of a conductive material such as aluminum (Al), titanium (Ti) Layer structure including at least one of chrome (Cr), nickel (Ni), copper (Cu), and gold (Au).

Electrons injected through the first conductive type semiconductor layer 242a and holes injected through the second conductive type semiconductor layer 242c formed after the first and second conductive type semiconductor layers 242a and 242b meet each other to form an active layer 242a, It is a layer that emits light with energy determined by the band.

The active layer 242b may be a double heterojunction structure, a single quantum well structure, a multiple quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. Or at least one of them may be formed. For example, the active layer 120 may be formed with multiple quantum well structures by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The well layer / barrier layer of the active layer 242b may be formed of any one of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, InAlGaN / InAlGaN, GaAs (InGaAs) / AlGaAs, GaP But it is not limited thereto. The well layer may be formed of a material having a bandgap narrower than the bandgap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 242b. The conductive clad layer may be formed of a semiconductor having a band gap wider than the band gap of the barrier layer of the active layer. For example, the conductive clad layer may include GaN, AlGaN, InAlGaN, superlattice structure, or the like. Further, the conductive clad layer may be doped with n-type or p-type.

The second conductivity type semiconductor layer 242c may be formed of a semiconductor compound. The second conductivity type semiconductor layer 242c may be formed of a compound semiconductor such as a group III-V element, a group II-VI element, or the like, and the second conductivity type dopant may be doped. For example, it may include a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? When the second conductive semiconductor layer 242c is a P-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as a P-type dopant.

A passivation layer 249 may be disposed around the light emitting structure 242 described above. The passivation layer 249 may be made of an insulating material, and the insulating material may be made of a non-conductive oxide or nitride. As an example, the passivation layer 249 may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

In this embodiment, the first conductive semiconductor layer 242a may be an N-type semiconductor layer, and the second conductive semiconductor layer 242c may be a P-type semiconductor layer. An N-type semiconductor layer (not shown) may be formed on the second conductive semiconductor layer 242c when the semiconductor having the opposite polarity to the second conductive type, for example, the second conductive semiconductor layer is a P-type semiconductor layer. Accordingly, the light emitting structure can be implemented by any one of an N-P junction structure, a P-N junction structure, an N-P-N junction structure, and a P-N-P junction structure.

The ohmic layer 245, the reflective layer 246, the bonding layer 247, and the conductive supporting substrate 248 may be disposed on the second conductive semiconductor layer 242c to serve as a second electrode.

The ohmic layer 245 and the reflective layer 246 may be disposed under the second conductive semiconductor layer 242c. The ohmic layer 245 can improve the contact characteristics of the second conductivity type semiconductor layer 242c and the reflective layer 246 and the like.

The ohmic layer 245 may be about 200 Angstroms thick. The ohmic layer 245 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide ), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO nitride), AGZO (Al- Ga ZnO), IGZO , NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Au, and Hf, and is not limited to such a material.

The reflective layer 246 may be composed of a metal layer comprising aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt or Rh . Aluminum, silver, or the like can effectively reflect the light generated in the active layer 242b, thereby greatly improving the light extraction efficiency of the light emitting device.

The supporting substrate 248 may be made of a conductive material or an insulating material. When the support substrate 248 is made of a conductive material, it may be formed of a metal or a semiconductor material, for example, molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu) (Au), a copper alloy (Cu Alloy), a nickel (Ni), a copper-tungsten (Cu-W), a carrier wafer (e.g., a GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga 2 O 3 , etc.), and the like may optionally be included.

The reflective layer 246 may be coupled to the conductive support substrate 248 through a bonding layer 247. The bonding layer 225 may be formed of gold (Au), tin (Sn), indium (In) A material selected from the group consisting of silicon (Si), silver (Ag), nickel (Ni) and copper (Cu), or an alloy thereof.

4A to 4C are views showing embodiments of the phosphor layer of the light emitting device package of FIG.

4A, a conformal-coated phosphor layer 270 covers the upper surface of the light-emitting element 240, and the upper surface of the light-emitting element 240 is partially exposed. In the exposed region, The wire 250 may be bonded to the light emitting element 240.

The embodiment shown in FIG. 4B is similar to the embodiment of FIG. 4A except that the top surface of the light emitting device 240 exposed to bond the wires 250 is located at the edge in FIG. 4A, but in FIG. .

In the embodiment shown in FIG. 4C, the phosphor layer 270 surrounds a part of the upper surface and the side surface of the light emitting device, and the phosphor layer 270 covers at least the active layer MQW.

5 is a diagram showing the distribution of the phosphor in the phosphor layer.

In the light emitting device according to the present embodiment, the phosphor layer 270 includes at least two phosphors, and a plurality of the first phosphors 274 and the second phosphors 277 are distributed in the resin layer 270a. The first phosphor 274 and the second phosphor 277 are excited by the light of the first wavelength region emitted from the light emitting device to emit light of the second wavelength region and light of the third wavelength region, respectively.

The light in the second wavelength region and the light in the third wavelength region may have a longer wavelength than the light in the first wavelength region and the light in the third wavelength region may be longer wavelength than the light in the second wavelength region, ) May be larger than the size of the second phosphor 277.

The size of the first phosphor 274 may be 10 to 13 micrometers and may be a yellow phosphor emitting yellow light. The size of the second phosphor 277 may be 8 to 10 micrometers and may be a red phosphor. Here, the size of the phosphors may be a diameter when the phosphor is spherical, or a length of one side or a diagonal length when the phosphor is polygonal.

FIG. 6 is a view comparing the light emission speed of the light emitting device package of FIG. 2 with other devices.

In case of the laser diode of (a), when an electrical signal is inputted, light is emitted immediately and in a very short time by stimulated emission, which may be advantageous for optical communication. In the case of the light emitting device of (b), light is emitted slowly and in a comparatively long time than in the case of the laser diode of (a) due to spontaneous emission after an electrical signal is inputted. In the case of the light emitting device package of (c) (B) and (c) show that light is emitted more slowly than in the case of (b) and (c) than in the case of (b) .

In the case of the light emitting device package in which the phosphor is applied to the light emitting device in FIG. 6, the response speed to the electrical signal is low. However, the light emitting device package according to the above- The reaction rate can be shown.

That is, the above-described light emitting device package has a relatively large size of the phosphor, and due to the scattering of light by the phosphor, mixing of color is relatively insufficient, which causes a large CCT deviation but may be advantageous in optical communication.

7A and 7B show the spectrum of the package of the light emitting device according to the embodiment and the CCT-to-CCT angle, respectively. Since the scattering of light is relatively small, the angle of directivity is narrow and it is advantageous in optical communication. It is possible to dispose a light emitting element on a flat substrate, which is not a cavity structure, and widen the directivity angle by using a lens.

FIGS. 8A and 8B and FIGS. 9A and 9B show a spectrum of the light emitting device package according to Comparative Examples 1 and 2 and a CCT-to-CCT angle, respectively. Comparative Example 1 is a light emitting device package using a YAG fluorescent material having a size of 4 to 5 micrometers and a red fluorescent material having a size of 8 to 10 micrometers. In Comparative Example 2, a LuAG fluorescent material having a size of 4 to 5 micrometers and a fluorescent material having a size of 8 to 10 micrometers Of the red phosphor.

As described above, the light emitting device package according to the present embodiment uses a relatively large (yellow) phosphor and emits light having a large CCT deviation because the color mixture is relatively insufficient due to light scattering. However, The reaction time is shorter than that in Comparative Examples 1 and 2, which can be advantageous for an illumination communication apparatus.

That is, the Cool White light emitting device package having a blue color region higher than the yellow color region in the spectrum may be advantageous for illumination communication than the warm white light emitting device package. In the case of implementing the Cool White light emitting device package, It may be advantageous to convert an electrical signal to light rather than to use it.

The light emitting device package may be mounted as one or a plurality of light emitting devices according to the embodiments described above, but the present invention is not limited thereto.

A plurality of light emitting device packages according to embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like may be disposed on the light path of the light emitting device package. Such a light emitting device package can be used in an illumination communication device.

10 is a diagram illustrating an embodiment of an illumination communication device including a light emitting device package.

The light emitted from the light emitting device module 401 in which the light emitting device package is disposed is reflected by the reflector 402 and the shade 403 and then transmitted through the lens 404, Lt; / RTI >

As described above, the light emitting device package used for the light emitting device module 401 uses a relatively large (yellow) phosphor, and the color mixture due to light scattering is relatively insufficient to emit light with a large CCT deviation However, since the scattering of light is small, the reaction time is shorter than that of Comparative Examples 1 and 2, which can be advantageous for an illumination communication apparatus.

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: light emitting device package 110, 210:
121, 221: first lead frame 122, 222: second lead frame
140, 240: light emitting device 150, 250: wire
160, 270a: resin layer 165: phosphor
270: Phosphor layer 274, 277: First and second phosphors
280: lens

Claims (10)

A first lead frame and a second lead frame disposed on the substrate and electrically separated from each other;
A light emitting element electrically connected to the first lead frame and the second lead frame to emit light in a first wavelength range;
A phosphor layer disposed on the light emitting element; And
And a lens disposed on the first lead frame and the second lead frame, the lens corresponding to the light emitting element,
The phosphor layer includes a first phosphor that is excited by light in the first wavelength region to emit light in a second wavelength region, and a second phosphor that is excited by light in the first wavelength region to emit light in a third wavelength region. Wherein the third wavelength is longer than the second wavelength and the size of the first phosphor is larger than the size of the second phosphor. The method according to claim 1,
The size of the first phosphor is 10 to 13 micrometers. The method according to claim 1,
Wherein the first phosphor is a yellow phosphor. The method according to claim 1,
And the second phosphor has a size of 8 to 10 micrometers. The method according to claim 1,
And the second phosphor is a red phosphor. The method according to claim 1,
And the phosphor layer is conformally coated on the light emitting element. The method according to claim 6,
And the phosphor layer covers an upper surface of the light emitting device. 8. The method of claim 7,
Wherein the phosphor layer surrounds at least a part of a side surface of the light emitting device and a phosphor layer surrounding the side surface of the light emitting device covers the active layer of the light emitting device. The method according to claim 1,
Wherein the substrate has a flat first surface on which the light emitting device is disposed. 10. An illumination communication device in which the light emitting element of any one of claims 1 to 9 is arranged.

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