KR100588209B1 - White light emitting device and method for fabricating the same - Google Patents

Abstract

The present invention relates to a white light emitting device and a method of manufacturing the same, and freely color the visible region using an epoxy dispersed in a Cd _(1-x) Zn _x Te phosphor which can change the energy band gap according to the amount of Zn. It can be made, there is an effect that can implement a white light emitting device with a wider degree of freedom than conventional devices.

White, luminescence, element, phosphor

Description

White light emitting device and method for manufacturing the same {White light emitting device and method for fabricating the same}             

1 is a cross-sectional view of a white light emitting device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating a principle in which white light is emitted from the white light emitting device of FIG. 1. FIG.

3 is a process flowchart of manufacturing a white light emitting device according to the first embodiment of the present invention.

4 is a cross-sectional view of a white light emitting device according to a second embodiment of the present invention.

5 is a conceptual diagram illustrating a principle of emitting white light in the white light emitting device of FIG. 4.

6 is a process flowchart of manufacturing a white light emitting device according to the second embodiment of the present invention.

7 is a schematic cross-sectional view of a light emitting device structure applied to the present invention;

8 is a graph measuring an energy band gap according to Zn concentration (Concentration) of the Cd _(1-x) Zn _x Te phosphor applied to the white light emitting device according to the present invention

<Description of Symbols for Main Parts of Drawings>

100 light emitting device structure 110 substrate

120: N type semiconductor layer 130: active layer

140: P-type semiconductor layer 150: N electrode

160: P electrode 200: reflecting plate

250, 270: epoxy 251: Cd _(1-x) Zn _x Te yellow phosphor

271: Cd _(1-x) Zn _x Te green phosphor 272: Cd _(1-x) Zn _x Te red phosphor

The present invention relates to a white light emitting device and a method of manufacturing the same, and more particularly, to a visible light region using an epoxy dispersed with a Cd _(1-x) Zn _x Te phosphor which can change an energy band gap according to the amount of Zn. The present invention relates to a white light emitting device and a method for manufacturing the same, which can freely make a color, and can implement a white light emitting device with a wider degree of freedom than a conventional device.

Recently, due to the rapid development of epitaxial growth technology and processes of gallium nitride (GaN), white light emitting diodes having high light output are currently receiving much attention.

Light emitting diodes are known to have many advantages such as high brightness, reliability, low power consumption, and long life.

Based on this, there is a movement to use a white light emitting diode for general lighting.

White light emitting diodes can generally be implemented in a number of ways, which are summarized in Table 1.

Way LED Source Light emitting material 1 LED chip  Blue LED InGaN / YAG: Ce  UV LED InGaN / R, G, B Phosphor 2 LED chips 1.Blue LED + Yellow LED 2.Blue Green LED + Amber LED InGaN, GaP, AlInGaP 3 LED chips Blue LED + Green LED + Red LED InGaN, AlInGaP

In Table 1, when implementing a white LED with one LED chip, first, a yellow fluorescent substance YAG: Ce is applied to the blue LED dispersed in the blue light emitted from the blue LED and the yellow fluorescent substance passed through The yellow light combines to emit white light from the device.

Secondly, R, G, B Phosphor dispersed epoxy is applied to the UV LED, and the light emitted from the UV LED passes through the R, G, B phosphor to generate R, G, B light. The R, G, and B lights are combined to emit white light from the device.

In addition, when implementing a white LED with two LED chips, first, the blue light emitted from the blue LED and the yellow light emitted from the yellow LED are combined to emit white light from the device.

Second, the blue-green light emitted from the blue-green LED and the amber light emitted from the Amber LED are combined to emit white light from the device.

In addition, when implementing a white LED with three LED chips, blue light emitted from a blue LED, a green LED, and a red LED, green light, and red light are combined to emit white light from the device.

In such a method according to the prior art, R, G, and B three LEDs in close proximity to each other, the method of light emission by mixing, respectively, there is a point that it is difficult to obtain a desired white because the color tone and brightness of the LED is irregular.

In addition, the method of containing a phosphor that absorbs a part of the light emitted from the LED and emits light having a different wavelength uses only inorganic yellow phosphors (YAG: Ce), so that the emission spectrum of the emitted light has a narrow peak and a yellow peak in the blue wavelength region. The halo effect caused by the wavelength separation phenomenon due to the wide peak in the wavelength range is generated, which makes it difficult to realize perfect white.

Therefore, there is a demand for the development of a new white LED to solve the above problems.

In order to solve the problems as described above, the color of the visible region can be freely made by using an epoxy dispersed in the Cd _(1-x) Zn _x Te phosphor which can change the energy band gap according to the amount of Zn. Therefore, an object of the present invention is to provide a white light emitting device capable of realizing a white light emitting device with a wider degree of freedom than a conventional device, and a method of manufacturing the same.

According to a preferred aspect of the present invention, there is provided a light emitting device structure;

A reflecting plate bonded to a lower surface of the light emitting device structure and reflecting light emitted from the light emitting device structure;

There is provided a white light emitting device including an epoxy covering the light emitting device structure and having a Cd _(1-x) Zn _x Te phosphor coated on the reflecting _plate dispersed therein.

Another preferred aspect for achieving the above object of the present invention comprises the steps of: forming a light emitting device structure;

Bonding a lower portion of the light emitting device structure to a reflector;

A method of manufacturing a white light emitting device is provided that includes covering the light emitting device structure and applying an epoxy in which a Cd _(1-x) Zn _x Te phosphor is dispersed on the reflective _plate .

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a white light emitting device according to a first embodiment of the present invention, which generates and emits blue light; A reflector plate 200 having a lower portion of the light emitting device structure 100 bonded to an upper surface thereof, surrounding the light emitting device structure 100 and reflecting blue light emitted from the light emitting device structure 100; The epoxy 250 may surround the light emitting device structure 100 and disperse the Cd _(1-x) Zn _x Te yellow phosphors 251 coated on the reflector 200.

That is, in the first embodiment of the present invention, as shown in Figure 2, the blue light emitted from the light emitting device structure 100 is changed to yellow light through the Cd _(1-x) Zn _x Te yellow phosphor 251 The yellow light and the blue light are combined to emit white light from the device.

3 is a flowchart illustrating a process of manufacturing a white light emitting device according to a first embodiment of the present invention, and forms a light emitting device structure that generates and emits blue light (step S10).

Thereafter, a lower portion of the light emitting device structure is bonded to the reflective plate (step S20).

Subsequently, an epoxy in which a Cd _(1-x) Zn _x Te yellow phosphor is dispersed is coated on the light emitting device structure and coated on the reflective _plate .

4 is a cross-sectional view of a white light emitting device according to a second embodiment of the present invention, which generates and emits blue light; A reflector plate 200 having a lower portion of the light emitting device structure 100 bonded to an upper surface thereof, surrounding the light emitting device structure 100 and reflecting blue light emitted from the light emitting device structure 100; The Cd _(1-x) Zn _x Te green phosphor 271 and the Cd _(1-x) Zn _x Te red phosphor 272 are disposed on the light emitting device structure 100 and coated on the reflector 200. And epoxy 270.

That is, in the second embodiment of the present invention, as shown in Figure 5, the blue light emitted from the light emitting device structure 100 is Cd _(1-x) Zn _x Te green phosphor 271 and Cd _{(1-x ) Is} emitted as green light and red light through the Zn _x Te red phosphor 272.

Therefore, blue light, green light and red light are combined to emit white light in the device.

6 is a flowchart illustrating a process of manufacturing a white light emitting device according to a second embodiment of the present invention, and forms a light emitting device structure that generates and emits blue light (step S50).

Thereafter, the lower portion of the light emitting device structure is bonded to the reflector (step S60).

Subsequently, an epoxy in which Cd _(1-x) Zn _x Te green phosphor and Cd _(1-x) Zn _x Te green phosphor are dispersed is coated on the light emitting device structure and coated on the reflective _plate .

7 is a schematic cross-sectional view of a light emitting device structure according to the present invention, in which an N-type semiconductor layer 120, an active layer 130, and a P-type semiconductor layer 140 are sequentially stacked on the substrate 110. Mesa is etched from the N-type semiconductor layer 120 to a portion of the P-type semiconductor layer 140, the N electrode 150 is formed on the mesa-etched N-type semiconductor layer 120, the P The P electrode 160 is formed on the type semiconductor layer 140.

FIG. 8 is a graph measuring an energy band gap according to Zn concentration (Concentration) of a Cd _(1-x) Zn _x Te phosphor applied to a white light emitting device according to the present invention. The square point a 'is measured by an energy dispersion spectroscopy (EDS) method, and the diamond point' b 'in FIG. 8 is measured by an X-ray diffraction method.

Here, it can be seen that the energy band gap increases linearly as the x value representing the concentration of Zn in the Cd _(1-x) Zn _x Te phosphor increases.

That is, the energy band gap from x to 0 is linearly increased from approximately 1.45 eV to 2.25 eV.

Therefore, the correspondence of the energy band gaps according to the x value of the Cd _(1-x) Zn _x Te phosphor can be represented as the checked region in the graph of FIG.

Thus, Eg = 1.96 eV at x = 0.75-0.81, Eg = 2.24 eV at x = 0.99-1, and Eg = 2.15 eV at x = 0.94-0.97.

At this time, the optical wavelength according to the energy band gap was calculated by Equation (1) below and is shown in Table 2.

Eg = 1234 / λ ----------- (1)

Kind of light Wavelength (nm) Eg (V) Zn concentration (x) Red light 630 1.96 0.75 to 0.8 Green light 550 2.24 0.99 to 1 Yellow light 575 2.15 0.94 to 0.97

On the other hand, the present invention by applying the epoxy dispersed in the Cd _(1-x) Zn _x Te phosphor having an x value of 0.5 to 1 to the light emitting device, it is possible to freely implement the color of the visible region by adjusting the x value, A white light emitting device may be realized by using a Cd _(1-x) Zn _x Te phosphor having an x value of 0.75 to 1.

In addition, in the first and second embodiments of the present invention, the light emitting device structure emitting blue light is applied, but a structure capable of emitting light of different wavelengths may be applied, and at the same time, Cd _(1-x) Zn _x Te By adjusting the color of the phosphor by adjusting the x value of the phosphor, it is possible to implement a device capable of emitting white light.

As described above, the present invention can implement a light emitting device capable of emitting white light by using an epoxy dispersed in a Cd _(1-x) Zn _x Te phosphor which can change the energy band gap according to the amount of Zn. do.

As described above, the present invention can freely make the color of the visible region by using an epoxy dispersed with a Cd _(1-x) Zn _x Te phosphor which can change the energy band gap according to the amount of Zn. There is an excellent effect that can implement a white light emitting device with a wider degree of freedom than the device.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (10)

A light emitting device structure; A reflecting plate bonded to a lower surface of the light emitting device structure and reflecting light emitted from the light emitting device structure; A white light emitting device comprising an epoxy surrounding the light emitting device structure and the Cd _(1-x) Zn _x Te phosphor coated on the reflecting _plate is dispersed. The method of claim 1, _{X in} the Cd _(1-x) Zn _x Te, White light emitting device, characterized in that 0.5 to 1. The method of claim 1, When the light emitting device structure is a structure that emits blue light, White light emitting device, characterized in that _{x of} the Cd _(1-x) Zn _x Te is 0.94 ~ 0.97. The method of claim 1, When the light emitting device structure is a structure that emits blue light, The Cd _(1-x) Zn _x Te phosphor is two kinds of materials, One substance is a Cd _(1-x) Zn _x Te phosphor with x of 0.99 to 1, Another material is a Cd _(1-x) Zn _x Te phosphor having x of 0.75 to 0.8. The method of claim 1, When the light emitting device structure is a structure that emits blue light, The Cd _(1-x) Zn _x Te phosphor is, It is a red phosphor, a green phosphor, or a yellow phosphor, The white light emitting element characterized by the above-mentioned. The method according to any one of claims 1 to 5, The light emitting device structure, An N-type semiconductor layer, an active layer, and a P-type semiconductor layer are sequentially stacked on the substrate, and Mesa is etched from the N-type semiconductor layer to a portion of the P-type semiconductor layer, and the upper portion of the mesa-etched N-type semiconductor layer The N-electrode is formed in the, the P-type semiconductor layer, characterized in that the P electrode is formed on the white light emitting device. Forming a light emitting device structure; Bonding a lower portion of the light emitting device structure to a reflector; And covering the light emitting device structure and applying an epoxy in which a Cd _(1-x) Zn _x Te phosphor is dispersed on the reflective _plate . The method of claim 7, wherein _{X in} the Cd _(1-x) Zn _x Te, 0.75-1, The manufacturing method of the white light emitting element characterized by the above-mentioned. The method according to claim 7 or 8, When the light emitting device structure is a structure that emits blue light, The method of manufacturing a white light emitting device, characterized in that _{x of} the Cd _(1-x) Zn _x Te is 0.94 ~ 0.97. The method according to claim 7 or 8, When the light emitting device structure is a structure that emits blue light, The Cd _(1-x) Zn _x Te phosphor is two kinds of materials, One substance is a Cd _(1-x) Zn _x Te phosphor with x of 0.99 to 1, Another material is a Cd _(1-x) Zn _x Te phosphor having x of 0.75 to 0.8.

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