KR101330045B1 - White-LED device using surface plasmon resonance of metallic nanoparticle - Google Patents

White-LED device using surface plasmon resonance of metallic nanoparticle Download PDF

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KR101330045B1
KR101330045B1 KR1020120024901A KR20120024901A KR101330045B1 KR 101330045 B1 KR101330045 B1 KR 101330045B1 KR 1020120024901 A KR1020120024901 A KR 1020120024901A KR 20120024901 A KR20120024901 A KR 20120024901A KR 101330045 B1 KR101330045 B1 KR 101330045B1
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South Korea
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blue light
light emitting
emitting diode
phosphor
diode chip
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KR1020120024901A
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Korean (ko)
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KR20130103899A (en
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최경철
이성민
김명철
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한국과학기술원
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched

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  • Manufacturing & Machinery (AREA)
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  • Led Device Packages (AREA)

Abstract

The white light emitting diode device includes a blue light emitting diode chip and a resin layer. The blue light emitting diode chip emits blue light, and the resin layer is formed on the blue light emitting diode chip, and includes at least one phosphor and at least one metal nanoparticle. The phosphor converts the blue light emitted from the blue light emitting diode chip into light of a wavelength different from that of the blue light for mixing with the blue light to realize the white light source. Metal nanoparticles generate surface plasmon resonance at different wavelengths of light, forming an electric field in the phosphor.

Description

White LED device using surface plasmon resonance of metallic nanoparticles

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to light emitting diode (LED) technology, and more particularly, to high brightness using surface plasmon resonance (LSPR, Localized Surface Plasmon Resonance) of metal nanoparticles (metal nanostructures). A white light emitting diode device.

A light emitting diode (LED), which is a typical light emitting device, is a compound semiconductor having a p-n junction structure and refers to a device that emits predetermined light by recombination of minority carriers (electrons or holes). LED devices have recently been widely used in mobile phones, monitor LCDs, and LCD TV backlights to lighting devices.

The LED device has low power consumption, long life, can be installed in a small space, and provides vibration resistance. Recently, in addition to single color components, for example, red, blue, or green light emitting diodes, white light emitting diodes have been introduced, and demand for them is rapidly increasing.

The light emitting diode may implement white light using a phosphor that is a wavelength conversion means. That is, by applying a phosphor on the light emitting diode, a part of the primary light emission of the light emitting diode and the secondary light emission wavelength-converted by the phosphor is mixed to achieve white. White light emitting diodes of this structure are widely used because of their low cost and very simple in principle and structure.

For example, yellow light green or yellow light emitting phosphors may be applied onto a light emitting diode emitting blue light as an excitation source, and white may be obtained by mixing blue light emitting light emitting diodes with yellow green or yellow light emitting phosphors.

The light emitting diode as described above is usually manufactured in a package structure, and a light emitting diode chip is mounted on a lead frame, and a structure covering a molding part containing a phosphor thereon is common.

The technical problem to be solved by the present invention, a high brightness white light emitting diode device using the surface plasmon resonance characteristics (local surface plasmon resonance (LSPR) phenomenon) of the metal nanoparticles to increase (improve) the luminous efficiency of the white LED device To provide.

In order to achieve the above technical problem, a white light emitting diode device according to an embodiment of the present invention, a blue light emitting diode chip for emitting blue light; And a resin layer formed on the blue light emitting diode chip, the resin layer including at least one phosphor and at least one metal nanoparticle, wherein the phosphor emits blue light emitted from the blue light emitting diode chip. The light may be mixed with the blue light and converted into light having a wavelength different from that of the blue light for realizing a white light source, and the metal nanoparticles may generate surface plasmon resonance in the light having the different wavelength to form an electric field in the phosphor. Can be.

The metal nanoparticles may be metal nanoparticles coated with a dielectric, and the phosphors may be yellow phosphors, or green phosphors and red phosphors constituting a pair. The metal nanoparticles may be gold (Au) nanoparticles or silver (Ag) nanoparticles.

The resin layer may further include a dispersant. When the phosphors are green phosphors and red phosphors constituting a pair, the metal nanoparticles may include silver (Ag) nanoparticles in a triangular form. The resin layer may be formed by dispersing the metal nanoparticles in an organic solvent, dispersing the phosphor in a resin included in the resin layer, and mixing the dispersed metal nanoparticle and the dispersed phosphor in the resin. .

In order to achieve the above technical problem, a white light emitting diode device according to another embodiment of the present invention, a blue light emitting diode chip for emitting blue light; And a resin layer formed on the blue light emitting diode chip, the resin layer including at least one quantum dot and at least one metal nanoparticle, wherein the quantum dot is a blue light emitted from the blue light emitting diode chip. And may be converted into light having a wavelength different from that of the blue light to implement a white light source, and the metal nanoparticles may generate surface plasmon resonance from the light having the different wavelength to form an electric field in the quantum dot.

The quantum dots may be yellow light emitting quantum dots, or green light emitting quantum dots and red light emitting quantum dots forming a pair.

In order to achieve the above technical problem, a white light emitting diode device according to another embodiment of the present invention, a blue light emitting diode chip for emitting blue light; And a resin layer formed on the blue light emitting diode chip, the resin layer including at least one metal nanoparticle coated with a phosphor, wherein the phosphor is configured to share blue light emitted from the blue light emitting diode chip with the blue light. The mixture may be converted into light having a different wavelength from the blue light for implementing a white light source, and the metal nanoparticles may generate surface plasmon resonance from the light having the different wavelength to form an electric field in the phosphor. The metal nanoparticles may be metal nanoparticles coated with a dielectric.

In order to achieve the above technical problem, a white light emitting diode device according to another embodiment of the present invention, a blue light emitting diode chip for emitting blue light; And a resin layer formed on the blue light emitting diode chip, the resin layer including at least one metal nanoparticle coated with quantum dots, wherein the quantum dots include blue light emitted from the blue light emitting diode chip. The mixture may be converted into light having a different wavelength from the blue light for realizing a white light source, and the metal nanoparticles may generate surface plasmon resonance from the light having the different wavelength to form an electric field in the quantum dot. The metal nanoparticles may be metal nanoparticles coated with a dielectric.

The present invention can greatly increase the luminous efficiency (light efficiency) of the light conversion white LED device by using the surface plasmon resonance characteristic generated in the metal nanoparticles. When the surface plasmon resonance characteristic of the metal nanoparticles is used, the light absorption and emission intensity of the phosphor or quantum dot included in the light conversion white LED device may be greatly increased, so that a smaller amount of phosphor or quantum dot A high light emission amount can also be obtained. Therefore, the low power consumption white LED device of the present invention adopting such a structure can be widely used in the back light of a TV or a monitor, and lighting equipment as a high efficiency display device.

That is, the white light emitting diode device (white LED device) according to the present invention uses the surface plasmon resonance characteristic of the metal nanoparticles in the white LED structure using the phosphor light conversion structure or the quantum dot light conversion structure ( Photoconversion efficiency) and finally the efficiency of the white LED device can be improved. Therefore, the efficiency of the backlight and the lighting device can be improved by improving the efficiency of the white LED device.

In detail, the present invention uses a metal nanoparticle suitable for the photoconversion phosphor or the photoconversion quantum dots without changing the chemical composition of the phosphor or the quantum dots in a white LED device using the photoconversion phosphor or the photoconversion quantum dots. By increasing (improvement) the excitation efficiency and the luminous efficiency, the luminous efficiency of the white LED element can be greatly improved. That is, the present invention utilizes a local surface plasmon resonance phenomenon occurring on the surface of metal nanoparticles in response to an incident light source (light generated by a phosphor or a quantum dot), thereby improving the light emission characteristics of a phosphor for a white LED or a quantum dot for a white LED. By increasing the luminous efficiency of the white LED device can be increased.

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.
1 is a diagram illustrating a white LED structure 10 compared with the present invention.
2 is a cross-sectional view showing a white light emitting diode device 100 according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a white light emitting diode device 200 according to another embodiment of the present invention.
4 is a cross-sectional view illustrating a white light emitting diode device 300 according to another exemplary embodiment of the present invention.
FIG. 5 is a view for explaining the resin layer illustrated in FIG. 2, 3, or 4.
6 is a view for explaining a white light emitting diode device according to another embodiment of the present invention.
FIG. 7 is a graph illustrating surface plasmon resonance characteristics of the metal nanoparticles illustrated in FIG. 2, 3, 4, or 6.
FIG. 8 is a graph illustrating an increase in emission of phosphors mixed with the metal nanoparticles illustrated in FIG. 2, 3, 4, or 6.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention and the objects attained by the practice of the invention, reference should be made to the accompanying drawings, which illustrate embodiments of the invention, and to the description in the accompanying drawings.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

When the white LED device is directly implemented with LED semiconductor chips of red (R), green (G), and blue (B) colors, the cost is complicated and the process is complicated. Phosphor converted LED (PC-LED) devices can be used. In the light conversion white LED device, green and yellow phosphors (green phosphor or yellow phosphor) are mainly used. In order to improve color purity and luminous efficiency, there may be a method of mixing phosphors and quantum dots.

White LEDs are used as backlights for TVs or monitors, and are being spotlighted as next-generation lighting devices that can replace fluorescent lamps in the future. However, it is very important to increase the luminous efficiency of such a device due to the cost reduction due to the increase in the price of the fluorescent material.

Before describing the present invention, a comparative example of the present invention will be described as follows.

1 is a diagram illustrating a white LED structure 10 compared with the present invention.

Referring to FIG. 1, the white LED 10 is a light conversion white LED, which includes a substrate 15, a cathode 20, an anode 22, a blue emitting LED chip 25, and a first mold (housing). 30, the second housing 32, the gold bonding wire 35, and the phosphors 40 contained in the transparent resin layer 45. The first housing 30 and the second housing 32 may be connected to each other.

The light conversion white LED 10 includes an LED chip 25 that is responsible for blue light emission and phosphors 40 that convert blue light into light having a different wavelength. The phosphors 40 may be configured as phosphors for converting blue light into yellow light or a plurality of phosphors for converting green light and red light. The phosphor 40 is basically excited by blue light and excited, and returns to a stable ground state to generate light of a different wavelength. A white light source may be implemented by mixing two or more wavelengths including the blue light and light having a different wavelength.

 As shown in FIG. 1, the cathode 20 electrode and the anode 22 electrode are connected to a semiconductor chip 25 having a multiple quantum well structure. At this time, the anode 22 is typically connected to the semiconductor chip 25 through a wire (gold bonding wire) 35 made of gold.

The semiconductor chip 25 is made of various compound semiconductors and has a junction structure (P-N junction structure) that generates light in a blue region due to recombination of electrons and holes.

A photoconversion phosphor layer comprising phosphor 40 and transparent resin 45 is applied over LED chip 25 and white LED 10 is Blue LED chip 25 + Yellow phosphor 40, or Blue LED chip. It may be composed of (25) + Green phosphor 40 + Red phosphor 40. The phosphor 40 is dispersed in the transparent resin 45, and the resin 45 is dried at a temperature of 100 degrees Celsius or more.

In order to improve the characteristics of the white LED (10), as a method of configuring the LED back plate (reflective plate disposed under the blue emitting LED chip 25) of a metallic material to minimize the loss of light to the rear, Development of new phosphors having high luminance characteristics is mainly made. However, luminescent ions used in such phosphors are usually composed of rare earth-based metal ions. As the price of rare earth metals continues to rise, there is a need for a method of replacing them or having a high luminance while using a small amount of rare earth metal. Situation.

2 is a cross-sectional view showing a white light emitting diode device 100 according to an embodiment of the present invention.

Referring to FIG. 2, a white light emitting diode device 100 includes a substrate 105, a cathode as the first electrode 110, an anode as the second electrode 112, and a blue light emitting diode chip ( chip 115, a first mold (housing) 120, a second housing (second cover) 122, a gold bonding wire 125, and a resin layer At least one phosphor 130 and at least one metal nanoparticle (metal nanostructure) 135 each included (inserted or dispersed) in 140 is included. The first housing 120 and the second housing 122 may be connected to each other to have a shape (structure) of a circular ring when viewed from above, and may be each implemented of a resin such as polyester. The white light emitting diode device 100 may use a phosphor photoconversion structure using a phosphor or a quantum dot photoconversion structure.

The substrate (lower substrate) 105 disposed below the first electrode 110 and the second electrode 112, and the upper substrate constituting the first housing 120 and the second housing 122 constitute a package substrate. can do. The first electrode 110, the second electrode 112, the lower substrate 105, and the upper substrate may be referred to as a lead frame.

The first electrode 110 and the second electrode 112 are connected to the blue light emitting diode chip 115, which may have a multiple quantum well structure. The second electrode 112 is connected to the blue light emitting diode chip 115 through the gold bonding wire 125.

The blue LED chip 115 emits (generates) blue light and is disposed on the cathode, which is the first electrode 110. The wavelength of the blue light may be 430 (nm) or more and 470 (nm) or less. The blue light emitting diode chip 115 is formed of various compound semiconductors, and when the power is applied through the first electrode 110 and the second electrode 112, electrons in the active layer included in the blue light emitting diode chip 115 are separated from each other. It may have a junction structure (PN junction structure) that generates light in the blue region due to the recombination of holes.

The resin layer 140 formed inside the upper substrate is formed (coated) on the blue light emitting diode chip 115 to surround the blue light emitting diode chip 115, and includes at least one phosphor 130 and at least one metal nanoparticle. And 135 resins. The resin means a natural solid, a synthetic solid, or an organic product, and may be a transparent resin such as a silicone resin, an epoxy resin, or a mixture thereof. When the resin is a transparent resin, the resin layer 140 may be implemented as a transparent resin layer.

The phosphor 130 absorbs blue light of the blue light emitting diode chip 115 and mixes the blue light emitted from the blue light emitting diode chip 115 with the blue light to implement (to implement) a white light source. Converts to blue light and light of a different wavelength. The phosphor 130 is a wavelength conversion phosphor (light conversion phosphor) and is excited by blue (blue) light of the blue light emitting diode chip 115 to convert the blue light into green light, yellow light, or red light. The phosphor 130 may be a yellow phosphor (Yellow photoconversion phosphor) that may include YAG (Yttrium-Aluminum-Garnet), or a green phosphor and a red phosphor mixed in a pair. The phosphor 130 is excited in the excited state by the blue light of the blue LED chip 115, and generates light of a different wavelength as it returns to the stable ground state. The white light source may be implemented by mixing two or more wavelengths including the blue light and light of different wavelengths. The phosphor 130 is dispersed in the resin layer 140, and the transparent resin included in the resin layer 140 may be dried at a temperature of 100 ° C. or more.

In another embodiment of the present invention, a wavelength converted quantum dot such as CdSe may be used instead of the phosphor 130, or both the phosphor 130 and the quantum dot may be used. LEDs to which quantum dots are applied may be referred to as hybrid LEDs. The quantum dots (semiconductor nanoparticles) may emit yellow light in a specific wavelength region, and may be green light emitting quantum dots or red light emitting quantum dots constituting a pair.

The metal nanoparticles 135 may be generated from the light having the different wavelength (the emission wavelength of the phosphor 130) (or the blue light of the blue light emitting diode chip 115, the absorption wavelength of the phosphor 130, and the blue light. The emission efficiency of the white light emitting diode device 100 may be increased by generating surface plasmon resonance in different wavelengths of light) and generating (inducing) an electric field in the phosphor 130. Surface plasmon resonance is a phenomenon in which metal plasmon vibrates collectively by surface plasmons of metal nanoparticles by resonating with light having a specific wavelength in the visible or infrared band, and occurs at a close distance from the surface of the metal thin film. Refers to a phenomenon in which fluorescence is enhanced by surface plasmons. When surface plasmon resonance occurs, metal nanoparticles absorb light of a resonance wavelength and emit clear light of its complementary color. Surface plasmons are analogous particles that refer to the collective vibration of free electrons occurring on the surface of a metal thin film. Plasmons excited at the surface of the planar metal layer are sometimes called surface plasmons because they propagate at the metal surface. In the case of nanoparticles, metals are called localized surface plasmons because excited plasmons do not propagate and are attributed within the near field of the nanoparticles. In the case of metal nanoparticles, the electric field of the ultraviolet-visible light band light source and the plasmon are paired with each other, resulting in light absorption and vivid color. Another similar particle produced by combining plasmon and photons is called plasma polaritone. Surface plasmon resonance generates a locally increased electric field, which means that light energy is converted to surface plasmons and accumulated on the surface of metal nanoparticles.

The metal nanoparticles 135 may have a size of greater than 0 (nm) and less than or equal to 500 (nm), for example. The metal nanoparticles 135 added to the resin layer 140 may have a surface in response to an incident light source (or blue light of the blue light emitting diode chip 115 and light of an emission wavelength at which the phosphors 130 or the quantum dots occur). Plasmon resonance can occur. As a result, a locally strong electric field is induced around the metal nanoparticles 135. The induced electric field enhances the light absorption and emission intensity of the phosphor 130 around the metal nanoparticles 135 and finally increases the luminous efficiency of the white LED device 100.

In another embodiment of the present invention, in consideration of the plasmon resonance position of the metal nanoparticles 135, the configuration of the phosphor 130 is a spherical or polyhedral form when using the green phosphor (green light emitting form) and the red phosphor Gold (Au) nanoparticles or silver (Ag) nanoparticles may be used. When silver (Ag) nanoparticles are used, spherical, polyhedral, or triangular silver (Ag) nanoparticles may be used to induce plasmon resonance suitable for yellow and red phosphors. That is, the white light emitting diode device 100 may be manufactured by mixing a blue LED chip, a green phosphor, a red phosphor, and silver (Ag) nanoparticles. The silver nanoparticles prepared in the triangular form may have a plasmon resonance of a red emission band (or a green emission band, a yellow emission band, and a red emission band). Meanwhile, the white light emitting diode device 100 may be manufactured by mixing a blue LED chip, a yellow phosphor, and gold (Au) nanoparticles.

In another embodiment of the present invention, the metal nanoparticles 135 may be particles in which gold (Au) nanoparticles and silver (Ag) nanoparticles are mixed.

In the case where the metal nanoparticles 135 are in direct contact with the phosphor 130 which is the light emitter, the quenching effect of reducing the light emission intensity (the light emission intensity of the phosphor) may occur, so that the metal nanoparticles are formed on the surface of the phosphor. It can be designed not to be attached. As a process method for such a configuration, the metal nanoparticles may be dispersed in an organic solvent first. Likewise, the phosphor may be dispersed in the resin and the metal nanoparticle dispersion organic solution may be added to the resin and mixed to design the phosphor and the nanoparticles to be evenly distributed in the resin layer. In detail, the metal nanoparticles 135 are dispersed in an organic solvent, the phosphor 130 is dispersed in a resin included in the resin layer 140, and the dispersed metal nanoparticles and the dispersed phosphor are mixed in the resin. The resin layer 140 can be formed by doing so. That is, the phosphors 130 and the metal nanoparticles 135 may be simultaneously dispersed in the resin layer 140.

As described above, the metal nanoparticles 135 generate plasmon resonance (plasmon resonance characteristic) in each phosphor emission band (phosphor emission wavelength). That is, the surface plasmon resonance characteristic of the metal nanoparticles 135 is localized and expressed around the metal nanoparticles 135. As the surface plasmon resonance characteristics appear, light absorption and emission efficiency (luminescence characteristics) of adjacent phosphors 130 may be greatly improved.

In more detail, the plasmon resonance characteristic may affect several tens of nanometers from the surface of the metal nanoparticles 135. A strong electromagnetic field (or electric field) is formed around the phosphor 130 (phosphor 130) located within this area of influence, and the optical density (light absorbed by the phosphor 130) is formed. Density (absorbance)) increases, so that the phosphor 130 has a higher emission intensity. That is, the emission intensity of the phosphor may be increased by placing the plasmon resonance band of the metal nanoparticle 135 in the emission region of the phosphor 130. This phenomenon occurs only in metal materials having plasmon resonance characteristics in the visible region (for example, Au), and is a common dielectric material, or a metal having plasmon resonance in a region other than the visible region. Can be difficult to achieve. By the above-described effect, the present invention has a high luminous luminance characteristic at the same driving voltage and finally the present invention can be implemented as a white LED device having a high luminous efficiency.

As described above, the present invention can increase the light efficiency of the phosphor or quantum dots for light conversion by using the surface plasmon resonance characteristics of the metal nanoparticles in the structure in which the metal nanoparticles are inserted into the resin layer including the phosphor or the quantum dots. . As a result, the present invention can significantly improve (improve) the light emission luminance and light emission efficiency of the white LED element. That is, according to the present invention, by applying a metal nanoparticle having a plasmon resonance band position overlapping the emission wavelength (luminescence region) of the phosphor, the emission intensity (luminance, emission efficiency, or light conversion characteristics) and light absorption of the phosphor or quantum dots are greatly increased. By increasing the efficiency of the white LED device 100 can be greatly improved.

3 is a cross-sectional view illustrating a white light emitting diode device 200 according to another embodiment of the present invention.

Referring to FIG. 3, the white light emitting diode device 200 may include a substrate 205, a first electrode 210, a second electrode 212, a blue light emitting diode chip 215, and a first mold (housing). ) 220, the second housing 222, the gold bonding wire 225, and the resin layer 245, each of the at least one phosphor 230, the at least one metal nanoparticle 235, and the dispersant 240. ) The first housing 120 and the second housing 122 may be connected to each other to have a shape (structure) of a circular ring when viewed from above, and may be each implemented of a resin such as polyester. The white light emitting diode device 200 may use a phosphor photoconversion structure or a quantum dot photoconversion structure.

Substrate 205, first electrode 210, second electrode 212, blue light emitting diode chip 215, first housing 220, second housing 222, gold bonding wire 225, and resin Description of the substrate 105, the first electrode 110, the second electrode 112, the blue light emitting diode chip 115, the first housing 120, the second housing 122, shown in FIG. Similar to the description of the gold bonding wire 125 and the resin, the substrate 205, the first electrode 210, the second electrode 212, the blue light emitting diode chip 215, the first housing 220, For a description of the second housing 222, the gold bonding wire 225, and the resin, the description of FIG. 2 may be referred to.

However, unlike the white light emitting diode device 100 of FIG. 2, the resin layer 245 included in the white light emitting diode device 200 of FIG. 3 further includes at least one dispersant 240 such as a polymer dispersant. Phosphor 230, at least one metal nanoparticle 235, and a dispersant 240. That is, the phosphor 230 and the metal nanoparticles 235 may be dispersed by the dispersant 240 in the resin layer 245.

The dispersant 240 minimizes (prevents) agglomeration between the phosphors 230 and the metal nanoparticles 235 and maintains a constant distance between the phosphor 230 and the metal nanoparticles 235. In order to be added (mixed) to the resin layer 245. Dispersant 240 may be, for example, an uncharged polymer (dispersant) such as poly vinyl pyrrolidone (PVP) or catyl trimethyl ammonium bromide (CTAB).

4 is a cross-sectional view illustrating a white light emitting diode device 300 according to another exemplary embodiment of the present invention.

Referring to FIG. 4, the white light emitting diode device 300 may include a substrate 305, a first electrode 310, a second electrode 312, a blue light emitting diode chip 315, and a first mold (housing). 320, the second housing 322, the gold bonding wire 325, and at least one phosphor 330 and the at least one metal nanoparticle 335 coated with a dielectric, respectively, included in the resin layer 340. It includes. The first housing 120 and the second housing 122 may be connected to each other to have a shape (structure) of a circular ring when viewed from above, and may be each implemented of a resin such as polyester. The white light emitting diode device 300 may use a phosphor photoconversion structure or a quantum dot photoconversion structure.

Substrate 305, first electrode 310, second electrode 312, blue light emitting diode chip 315, first housing 320, second housing 322, gold bonding wire 325, and resin Description of the substrate 105, the first electrode 110, the second electrode 112, the blue light emitting diode chip 115, the first housing 120, the second housing 122, shown in FIG. Similar to the description of the gold bonding wire 125 and the resin, the substrate 305, the first electrode 310, the second electrode 312, the blue light emitting diode chip 315, the first housing 320, The description of the second housing 322, the gold bonding wire 325, and the resin may be referred to the description of FIG. 2.

However, unlike the white light emitting diode device 100 of FIG. 2, the resin layer 245 included in the white light emitting diode device 300 of FIG. 4 is a metal nanoparticle 335 coated with a dielectric instead of the metal nanoparticles 135. And phosphors 330.

The metal nanoparticles 335 coated with the dielectric play a role of minimizing aggregation between the phosphors 330 and the metal nanoparticles and maintaining a constant distance between the phosphor 330 and the metal nanoparticles. The dielectric may be, for example, SiO 2 , Al 2 O 3 , ZnO, or TiO 2 (titanium dioxide), the thickness of which may be greater than 0 (nm) and less than or equal to 100 (nm).

FIG. 5 is a view (sectional view) for explaining the resin layer illustrated in FIG. 2, 3, or 4.

Referring to FIG. 5, phosphors and metal nanoparticles are mixed and dispersed in a resin layer. The LED chip (115 of FIG. 2, 215 of FIG. 3, or 315 of FIG. 4) may be composed of two layers. Each of the two layers may be a substrate and a semiconductor layer disposed on the substrate. The semiconductor layer includes a lower semiconductor layer including an n-type semiconductor, an upper semiconductor layer including a p-type semiconductor, positioned between the lower semiconductor layer and the upper semiconductor layer, emitting blue light, and having a multi-quantum well structure and having InGaN. It may include an active layer that may include.

6 is a view for explaining a white light emitting diode device according to another embodiment of the present invention.

Referring to FIG. 6A, a configuration in which a phosphor or a quantum dot is an outer layer and metal nanoparticles are an inner layer is illustrated. That is, the metal nanoparticles are coated with phosphors or quantum dots. In another embodiment of the present invention, the at least one coated metal nanoparticle is a phosphor 130 and a metal nanoparticle 135 (or metal nanoparticles) in the resin layer 140 included in the white light emitting diode device of FIG. 2. The core-shell structure (in which the core and the shell are combined), which is inserted instead of the particle 135 and is the coated metal nanoparticle, is dispersed in the resin layer.

Referring to FIG. 6 (b), a configuration in which phosphors or quantum dots are used as an outer layer and metal nanoparticles coated with a dielectric (dielectric layer) is used as an inner layer is illustrated. That is, metal nanoparticles coated with a dielectric are coated with phosphors or quantum dots. In another embodiment of the present invention, the at least one coated metal nanoparticle is a phosphor 130 and a metal nanoparticle 135 (or metal nanoparticles) in the resin layer 140 included in the white light emitting diode device of FIG. 2. The core-shell structure (in which the core and the shell are combined), which is inserted instead of the particle 135 and is the coated metal nanoparticle, is dispersed in the resin layer.

When using luminescent particles composed of phosphors or quantum dots and metal nanoparticles, metal nanoparticles coated with a dielectric (dielectric material) of SiO 2 , Al 2 O 3 , ZnO, or TiO 2 may be used as a core.

By using the configurations shown in FIGS. 6A and 6B, light absorption (eg, blue light absorption) of the metal nanoparticles can be minimized, and light emission of the phosphor or quantum dots can be maximized.

FIG. 7 is a graph illustrating surface plasmon resonance characteristics of the metal nanoparticles illustrated in FIG. 2, 3, 4, or 6. That is, FIG. 7 is a graph showing plasmon resonance characteristics when the metal nanoparticle is a gold material.

Referring to FIG. 7, the surface plasmon resonance characteristics of the metal nanoparticles can be observed through an extinction (au, arbitrary unit) spectrum, and the extinction is represented by the sum of absorption and scattering. .

The first curve 705 indicates the quenching spectrum of the gold nanoparticles dispersed in an organic solvent such as ethanol, and the second curve 710 the quenching of the gold nanoparticles dispersed in water. Indicate the spectrum.

As shown in FIG. 7, the plasmon resonance wavelength of the gold (Au) nanoparticles dispersed in the ethanol solvent is about 520 nm (within the wavelength range of the yellow phosphor) and the gold (Au) nanoparticles dispersed in the water solvent. It can be seen that the plasmon resonance wavelength is about 670 nm (in the wavelength region of the Red phosphor).

Therefore, the gold (Au) nanoparticles dispersed in the ethanol solvent may increase the emission intensity of the yellow phosphor, and the gold (Au) nanoparticles dispersed in the water solvent may increase the emission intensity of the red phosphor.

FIG. 8 is a graph illustrating an increase in emission of phosphors mixed with the metal nanoparticles illustrated in FIG. 2, 3, 4, or 6. That is, FIG. 8 is a graph illustrating the amount of increase in emission of the yellow phosphor when the metal nanoparticle is a gold material.

Referring to FIG. 8, when the concentration of gold nanoparticles, the horizontal axis value of the graph, increases, the integrated intensity (au, arbitrary unit), which is the emission intensity of the yellow phosphor in the emission of blue light, is increased. It can be seen. That is, as shown in FIG. 8, it can be seen that the emission intensity of the yellow light emitting phosphor increases as the content of the gold nanoparticles mixed with the yellow light emitting phosphor increases. Since the light emission intensity of the yellow light emitting phosphor is increased, the luminous efficiency of the white light emitting diode device may be increased as a result.

As described above, the embodiments have been disclosed in the drawings and specification. Although specific terms are used herein, they are used for the purpose of describing the present invention only and are not used to limit the scope of the present invention described in the claims or the claims. It is therefore to be understood by those skilled in the art that various modifications and equivalent embodiments are possible in light of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

115: blue light emitting diode chip
130: phosphor
135: metal nanoparticles
140: resin layer
215: blue light emitting diode chip
230: phosphor
235: metal nanoparticles
240: dispersant
245: resin layer
315: blue light emitting diode chip
330: phosphor
335: metal nanoparticles coated with a dielectric
340: resin layer

Claims (13)

A blue light emitting diode chip emitting blue light; And
A resin layer formed on the blue light emitting diode chip, the resin layer including at least one phosphor and at least one metal nanoparticle;
The phosphor converts blue light emitted from the blue light emitting diode chip into light having a wavelength different from that of the blue light for implementing a white light source by mixing with the blue light.
The metal nanoparticles generate surface plasmon resonance in the light of the different wavelength to form an electric field in the phosphor,
The metal nanoparticle is a white light emitting diode device is a metal nanoparticle coated with a dielectric. delete The method of claim 1,
The phosphor is a yellow phosphor or a green phosphor and a red phosphor forming a pair. The method of claim 1,
The metal nanoparticles are gold (Au) nanoparticles or silver (Ag) nanoparticles. The method of claim 1,
The resin layer further comprises a dispersant white light emitting diode device. The method of claim 1,
When the phosphors are green phosphors and red phosphors constituting a pair, the metal nanoparticles include silver (Ag) nanoparticles in a triangular form. The method of claim 1,
White light emission which forms the resin layer by dispersing the metal nanoparticles in an organic solvent, dispersing the phosphor in a resin included in the resin layer, and mixing the dispersed metal nanoparticle and the dispersed phosphor in the resin. Diode elements. A blue light emitting diode chip emitting blue light; And
A resin layer formed on the blue light emitting diode chip and including at least one quantum dot and at least one metal nanoparticle;
The quantum dot converts blue light emitted from the blue light emitting diode chip into light having a wavelength different from that of the blue light for implementing a white light source by mixing with the blue light,
The metal nanoparticles generate surface plasmon resonance in the light of the different wavelength to form an electric field in the quantum dot,
The metal nanoparticle is a white light emitting diode device is a metal nanoparticle coated with a dielectric. 9. The method of claim 8,
The quantum dots are yellow light emitting quantum dots or green light emitting quantum dots and red light emitting quantum dots forming a pair. A blue light emitting diode chip emitting blue light; And
A resin layer formed on the blue light emitting diode chip and including at least one metal nanoparticle coated with a phosphor;
The phosphor converts blue light emitted from the blue light emitting diode chip into light having a wavelength different from that of the blue light for implementing a white light source by mixing with the blue light.
The metal nanoparticles generate surface plasmon resonance in the light of the different wavelength to form an electric field in the phosphor. The method of claim 10,
The metal nanoparticle is a white light emitting diode device is a metal nanoparticle coated with a dielectric. A blue light emitting diode chip emitting blue light; And
A resin layer formed on the blue light emitting diode chip and including at least one metal nanoparticle coated with quantum dots,
The quantum dot converts blue light emitted from the blue light emitting diode chip into light having a wavelength different from that of the blue light for implementing a white light source by mixing with the blue light,
The metal nanoparticles generate a surface plasmon resonance in the light of the different wavelength to form an electric field in the quantum dot. The method of claim 12,
The metal nanoparticle is a white light emitting diode device is a metal nanoparticle coated with a dielectric.
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