JP2003249689A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of reducing color dispersion in a plurality of light emitting devices and improving reliability and mass- productivity. <P>SOLUTION: The light emitting device has a light emitting element 5 having a pair of positive and negative electrodes on the same face side and capable of emitting a part of light from side end faces, and a color conversion layer 6 having a fluorescent substance capable of absorbing a part of light emitted from the light emitting element 5 and emitting light of a different wavelength. The light emitting element 5 is mounted on a substrate having an external electrode on its surface as a flip chip through an anisotropic conductive layer 4 having conductive gains 4a, and the color conversion layer 6 is laminated on the conductive layer 4 extended to the periphery of the element 5 so as to come into contact with the layer 4. One side of the side end faces of the element 5 is coated with the conductive layer 4, and the other side is coated with the color conversion layer 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly to a light emitting device capable of obtaining uniform light emission with little color unevenness, for example, white light at high output.

[0002]

2. Description of the Related Art Today, a semiconductor light emitting device having high brightness and high output and a light emitting device having a small size and high sensitivity have been developed and used in various fields. Such a light emitting device takes advantage of features such as small size, low power consumption, and light weight, and is, for example, an optical printer head light source, a liquid crystal backlight light source, a light source for various meters,
It is also used for various reading sensors.

A light emitting diode (hereinafter referred to as L
Also called ED. ) Is small, efficient, and capable of emitting bright colors. In addition, since it is a semiconductor element, it does not run out of spheres, has excellent initial drive characteristics and earthquake resistance, and is an ON / O
It has a feature that it is strong against repeated FF lighting. Therefore, it is widely used as various indicators and various light sources. However, since the LED has an excellent monochromatic peak wavelength, it is difficult to emit an emission wavelength such as white.

Therefore, in recent years, a light emitting diode has been used in which light emitted from a light emitting element is color-converted by a phosphor and output. This light emitting diode can emit other emission colors such as white based using one type of light emitting element.

For example, in the case of constructing a white light emitting device, while a semiconductor light emitting element emits blue light, a fluorescent substance that emits yellow light is dispersed in a sealing resin that seals the semiconductor light emitting element. Then, the fluorescent substance absorbs a part of the light emitted from the semiconductor light emitting element to convert the wavelength to emit yellow light, and a light emitting diode capable of emitting white mixed color light by mixing these blue light and yellow light. It can be formed (for example, see Patent Document 1).

[0006]

[Patent Document 1] Japanese Patent Publication No. 2000-512806

[0007]

However, a remarkable color variation is observed between the light emitting diodes thus formed.

Nowadays, white light emitting diodes are used for indoor displays and lighting, and more strict color tones are required. These color variations are a serious problem.

On the other hand, although it is possible to configure an LED display or the like by selecting a white light emitting diode which has a very small variation in light emission under constant power, the yield is extremely low.

Therefore, the present invention provides a light emitting device which solves the above problems and is capable of obtaining a uniform mixed color light with less color unevenness at a high output and having less color variation between the light emitting devices and excellent mass productivity. The challenge is to provide.

[0011]

A light emitting device according to the present invention includes a light emitting element having a pair of positive and negative electrodes on the same surface side and capable of emitting a part of light emission from a side end surface, and the light emitting element. A light-emitting device comprising: a color conversion layer having a fluorescent substance capable of absorbing a part of light of an element and emitting light having a different wavelength, wherein the light-emitting element has an external electrode on a surface thereof. Is flip-chip mounted via an anisotropic conductive layer having conductive particles, and the color conversion layer is the anisotropic conductive layer extending around the light emitting element. Laminated in contact with the upper side, the lateral end face of the light emitting element is characterized in that one side in the thickness direction is covered with the anisotropic conductive layer and the other side is covered with the color conversion layer. .

One of the features of the present invention is that a member for blocking light such as an electrode is not arranged on the light emitting surface side, and a part of the side end surface of the light emitting element is covered with a color conversion layer, and the other side end surface is covered. The point is covered with an anisotropic conductive layer having conductive particles. Thus, a part of the light emitted from the electrode formation surface side and the side end surface of the light emitting element is guided to the anisotropic conductive layer arranged on the bottom surface side of the color conversion layer, and the guided light is different from the anisotropic conductive layer. The conductive particles in the isotropic conductive layer can be reflected and scattered, and can be efficiently taken out to the color conversion layer in the upper layer portion. As a result, the excitation light can be irradiated to the bottom surface side of the color conversion layer that has not been effectively used until now, and the conversion efficiency of the fluorescent substance can be dramatically improved.

Further, the color conversion layer has a shape in which it rises vertically from the upper surface of the anisotropic conductive layer with a substantially uniform thickness, and the fluorescent substance is added to 100 parts by weight of the translucent member. 30 parts by weight to 100 parts by weight are contained. Thus, the fluorescent substance content of the color conversion layer placed only on the lateral end face side without placing the fluorescent substance above the light emitting element is changed so that the light emitted from the color conversion layer is emitted from the fluorescent substance. By adjusting so that only the emitted light is emitted, the monochromatic light of the light emitting element itself and the monochromatic light emitted from the color conversion layer can be extracted with high output. In this way, by keeping the location of the fluorescent substance constant,
It is possible to obtain a light-emitting device that can emit light with high output without color variation between the light-emitting devices with high yield.

Further, the color conversion layer has substantially the same thickness as the light emitting element, and has a continuous diffusion layer in contact with the exposed surface of the light emitting element and the exposed surface of the color conversion layer. To do. As a result, the color mixing properties of the light emitted from the light emitting element and the light emitted from the fluorescent material can be enhanced.

Further, a plurality of the light emitting elements are mounted on both sides of the color conversion layer. Specifically, it is an integrated optical device in which a plurality of light emitting elements are mounted on a base surface having an external electrode with a constant space, and the space is sealed with the color conversion layer. In the present invention, since an anisotropic conductive layer that is also an electrical connecting means is used as a member that guides a part of the light from the light emitting element to the bottom surface side of the color conversion layer, a large number of electrodes and substrates on the light emitting element side are used. It is possible to connect a large number of electrodes on the surface side with high reliability at one time, and it is possible to mount many miniaturized light emitting elements with high reliability and high density. As a result, an integrated light emitting device having further excellent color mixing property can be obtained.

As the light emitting element, it is also possible to use an array light emitting element having a plurality of light emitting layers, that is, an array light emitting element having a plurality of positive and negative pairs of electrodes on the same surface side. As described above, in the present invention, the anisotropic conductive layer has optical characteristics, reliability, optical characteristics,
It can also be said to be an excellent member that enhances productivity.

[0017]

DETAILED DESCRIPTION OF THE INVENTION As a result of various experiments, the present inventor
In a light emitting device using a fluorescent substance, by guiding the light emitted from the light emitting element so that it can be utilized to the maximum extent, the luminous intensity of the light emitting device is improved, and color variation and uneven color between the light emitting devices are improved. It was found that the above was possible, and the present invention was accomplished.

The color conversion type light emitting device emits monochromatic light from the semiconductor light emitting element, and at the same time, emits light having different wavelengths by absorbing a part of the monochromatic light in a sealing resin for sealing the semiconductor light emitting element. Disperse the possible fluorescent substance,
The mainstream method is to obtain a desired color tone by mixing these lights.

However, the specific gravity of the fluorescent substance reaches several times that of the liquid resin, and the thermosetting resin has a large decrease in viscosity after being cured by heating. Therefore, the light emitting element is made of the liquid resin containing the fluorescent substance. Under the present circumstances, most of the fluorescent substances in the resin are densely gathered around the light emitting element and settled when the coating and heat curing are performed. The fluorescent substance collected and settles to some extent and settles around the light emitting element. For this reason,
In reality, it is considered that only the fluorescent substance located on the outermost surface around the light emitting device absorbs light from the light emitting device most efficiently, and most other fluorescent substances cannot exert their original functions and simply absorb the energy of light. It is an obstacle to the decline.

On the other hand, a number of methods have been proposed in which a light emitting element is electrically connected to a package having a pair of positive and negative electrodes on the bottom surface of a recess, and the inside surface of the package side wall is coated with a fluorescent material. 10-112557
Japanese Patent Laid-Open No. 11-274572, etc.).
Although the light emitted from the upper surface of the light emitting element can be efficiently extracted by this method, the light emitted from the lateral end surface of the light emitting element has not been sufficiently utilized.

Therefore, according to the present invention, all the fluorescent substances are efficiently irradiated with the excitation light from the light emitting element, and further the mounting place of the fluorescent substances is determined, so that the luminance is high and the color variation between the light emitting devices is small. A color conversion type light emitting device is realized.

The present invention will now be described with reference to specific examples shown in the drawings.
Will be described in detail. FIG. 1 shows an SMD which is a mode of the present invention.
FIG. 3 is a schematic cross-sectional view of a type light emitting diode. Has a recess,
The surface of the pair of lead electrodes 2 and 3 is exposed from the bottom surface of the recess.
Use the package 1 that is insert-molded as
The bottom surface of the recess and the electrode formation surface side of the light emitting element 5 face each other.
And the anisotropic conductive layer 4 is interposed in contact with the respective facing surfaces.
And are electrically connected. Also, the anisotropic conductive layer
4 is continuously formed on the entire bottom surface of the recess. Anisotropy
The light emitted from the light emitting element is efficiently reflected in the electrode layer.
Conductive particles 4a capable of being formed and having conductivity
Is included. The light emitting element 5 is a sapphire substrate.
Nitride semiconductor over the buffer layer, which is gallium nitride
Body (Al _xGa_yIn_zN, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1,
0 ≦ z ≦ 1, X + Y + Z = 1) formed pn junction
Has been done. In addition, the anisotropic conductive layer 4 surrounds the light emitting element.
In contact with the surface of the anisotropic conductive layer 4,
It absorbs part of the light from the light emitting element and emits light of different wavelengths.
Provided is a color conversion layer 6 having a fluorescent substance capable of emitting light.
Has been. In addition, the lateral end surface of the light emitting element is
The lower part of the base surface is the anisotropic conductive layer 4.
And the other upper part is covered with the color conversion layer 6.
ing. Further, the surface of the light emitting element 5 and the surface of the color conversion layer 6 are
The planes are almost parallel and there is continuous diffusion in contact with these planes.
Layers are provided. The following are embodiments of the present invention
Each component of the light emitting device will be described in detail. [Light Emitting Element 5] In the present invention, the light emitting element 5 is on the same surface side.
Has a pair of positive and negative electrodes and part of the light emission from the side end face.
It is not particularly limited as long as it can emit light, but it is used
Has a light-emitting layer that can emit light at a wavelength that can excite fluorescent substances.
It is preferable to use a semiconductor light emitting device. like this
Various semiconductors such as ZnSe and GaN as semiconductor light emitting devices
The body can be mentioned, but the fluorescent substance can be excited efficiently.
Nitride semiconductor (In
_XAl_YGa_1-XYN, 0 ≦ X, 0 ≦ Y, X + Y ≦
1) is preferable. As a semiconductor structure, MI
Homostructure having S junction, PIN junction, pn junction, etc.,
Hetero structure or double hetero structure
It The emission wavelength depends on the material of the semiconductor layer and its mixed crystallinity.
Can be selected. In addition, the semiconductor active layer has a quantum effect.
Single quantum well structure and multiple weights formed in a thin film that produces fruit
A child well structure can also be used.

When a nitride semiconductor is used, materials such as sapphire, spinel, SiC, Si and ZnO are preferably used for the semiconductor substrate. A sapphire substrate is preferably used in order to form a nitride semiconductor having good crystallinity with good mass productivity. MOCVD on this sapphire substrate
A nitride semiconductor can be formed by using a method or the like. A buffer layer of GaN, AlN, GaAIN or the like is formed on a sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer made of n-type gallium nitride on a buffer layer and a first clad made of n-type aluminum gallium nitride / gallium. A layer, an active layer formed of indium gallium nitride, a second cladding layer formed of p-type aluminum nitride gallium, and a second contact layer formed by sequentially stacking a second contact layer formed of p-type gallium nitride. Can be mentioned. Nitride semiconductor
It exhibits n-type conductivity in a state where it is not doped with impurities. In the case of forming a desired n-type nitride semiconductor such as improving the luminous efficiency, Si, Ge, Se, T is used as the n-type dopant.
It is preferable to introduce e, C and the like as appropriate. On the other hand, when forming a p-type nitride semiconductor, p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since it is difficult for a nitride semiconductor to become p-type by only doping with a p-type dopant, it is preferable to reduce the resistance by heating with a furnace or plasma irradiation after introducing the p-type dopant. After forming the electrodes, a light emitting device made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips.

When the white light is emitted in the light emitting diode of the present invention, the emission wavelength of the light emitting element should be 400 nm or more and 530 nm or less in consideration of the complementary color relationship with the emission wavelength from the fluorescent material, the deterioration of the translucent resin, and the like. Preferably 420n
It is more preferably m or more and 490 nm or less. In order to further improve the excitation efficiency and the emission efficiency of the light emitting element and the fluorescent substance, 450 nm or more and 475 nm or less are more preferable. When the fluorescent material of the color conversion layer, the diffusion layer, and the translucent member which is a constituent member of the anisotropic conductive layer are made of resin or inorganic glass that is relatively resistant to deterioration by ultraviolet rays, the length is shorter than 400 nm. It is also possible to use a light emitting element having a main emission wavelength in the ultraviolet region or the short wavelength region of visible light. A color conversion type light emitting device using a light emitting element having a wavelength in the ultraviolet region has a chromaticity determined only by the emission color converted by the fluorescent substance, so it is compared with the case of using a semiconductor light emitting element that emits visible light. As a result, it is possible to absorb variations in the wavelength of the semiconductor light emitting device and improve mass productivity. [Anisotropic Conductive Layer 4] In the present embodiment, the light emitting element is mounted such that the electrode formation surface side on which a pair of positive and negative electrodes is provided faces the external electrode exposed from the bottom surface of the package recess, Flip-chip mounting is performed via the continuous anisotropic conductive layer 4.

In the present invention, the anisotropic conductive layer 4 is capable of efficiently reflecting the light from the light emitting element and has conductivity in a material made of a thermoplastic or thermosetting organic or inorganic material. Conductive particles are dispersed. As a material made of an organic material having thermoplasticity or thermosetting property,
For example, a transparent resin such as an epoxy resin, an acrylic resin, or silicone is preferably used. Specific examples of the conductive particles include Ni particles, and particles having a metal coat of Ni, Au, or the like on the surface of particles such as plastic and silica. In the present invention, the content of the conductive particles is preferably 0.3 vol% or more and 1.2 vol% or less with respect to the adhesive, and such an anisotropic conductive layer can be formed by applying heat and pressure when mounting a light emitting element. High conductivity can be easily obtained between the film thickness directions of the layers. On the other hand, since the filling amount of the conductive particles is small in the plane direction of the layer, a short circuit between adjacent electrodes due to contact between the conductive particles does not occur, and high insulation can be maintained. More preferably, when the number of 1 mm ² particles in the anisotropic conductive layer is 3500 or more and 5000 or less, a small light emitting element having a narrow pitch between electrodes can be finely connected to an external electrode on the base surface with high reliability. You can Further, the anisotropic conductive layer can efficiently reflect and scatter light from the light emitting element to the color conversion layer in the upper layer portion.

In the present invention, the anisotropic conductive layer 4 is
The surface of the light emitting element and the base surface facing each other are hermetically sealed, and a part of the lateral end surface of the light emitting element is directly covered. Thereby, a part of the light emitted from the light emitting element is taken into the anisotropic conductive layer, reflected and scattered by the conductive particles in the anisotropic conductive layer, and the fluorescent substance in the color conversion layer is irradiated from below. can do. In the conventional light emitting device, only the fluorescent substance adjacent to the light emitting element or the fluorescent substance existing on the outermost surface is efficiently excited, and the other fluorescent substance buried below cannot sufficiently perform its original function. It was However, in the present invention, by irradiating a part of the light emitted from the end surface of the light emitting element over the entire surface from below the conversion layer, the color conversion layer is the outermost surface, the side surface adjacent to the light emitting element, and the anisotropic layer. Since the excitation light is irradiated from the lower side in contact with the conductive film, the color conversion efficiency can be improved in most fluorescent substances. Further, even when the light converted by the color conversion layer is reflected in the direction of the base surface, the conductive particles in the anisotropic conductive layer can quickly change the path and extract the light upward. [Color conversion layer 6] In the light emitting device of the present invention, the anisotropic conductive layer extends to the end portion of the base surface, and is in contact with the upper surface of the extending portion of the anisotropic conductive layer and the end surface on the side of the light emitting element. And a color conversion layer is provided. With this structure, the color conversion layer is irradiated with excitation light from the side end face of the adjacent light emitting element and also absorbs light from the light emitting element from the lower surface via the anisotropic conductive film. You can As a result, the color conversion layer can absorb the excitation light from the entire surface, and thus it is possible to obtain a light emitting device capable of emitting light with high brightness with the minimum necessary amount of the fluorescent substance.

In the present embodiment, the color conversion layer is made of a translucent member containing a fluorescent substance capable of absorbing a part of the light of the light emitting element and emitting light of different wavelengths. The translucent member, depending on the characteristics and use of the light emitting element to be used,
Both organic and inorganic substances can be used. As a specific material of the translucent member that is preferably used in the present invention, a transparent resin having excellent weather resistance such as epoxy resin, acrylic resin, or silicone, or glass is preferably used. Here, by including the same material as the material contained in the anisotropic conductive layer as the material of the color conversion layer, the adhesiveness between the anisotropic conductive layer and the color conversion layer is improved, and the separation of the two is prevented. You can Further, a pigment may be contained together with the fluorescent substance.

Further, the color conversion layer has a shape in which it rises vertically from the anisotropic conductive layer with a substantially uniform thickness, and the content of the fluorescent substance is 100 with respect to 100 parts by weight of the translucent member.
When the amount is not less than 200 parts by weight and not more than 200 parts by weight, a light emitting device capable of emitting light with high output can be obtained with high productivity.

As a light emitting device, a short wavelength around 400 nm
A light-emitting element that can emit ultraviolet light whose main emission peak is
When used, the color conversion layer should be a resin or glass that is relatively resistant to ultraviolet rays.
It is possible to emit visible light by absorbing the above ultraviolet rays with
It is preferable to use a fluorescent substance that is capable. like this
Phosphors that can fluoresce red, blue, and green with short-wavelength light
Quality, eg Y as red phosphor_TwoO_TwoS: Eu, blue firefly
Sr as a light body₅(PO _Four)_ThreeCl: Eu, and green firefly
As an optical body (SrEu) O ・ Al_TwoO_ThreeThe UV resistance
Side end face of a light emitting device that emits short wavelength light when contained in resin, etc.
White light can be obtained by arranging as a color conversion thin film layer on
You can In this way, use a light-emitting element that emits short wavelength light.
If the light emitting element is not transparent, the substrate side of the light emitting element is not transparent.
In addition, the anisotropic conductive layer and the diffusion layer have the same ratio as the color conversion layer.
Use resin or glass that is strong against comparative ultraviolet rays as the main agent
Is preferred. In addition to the above-mentioned fluorescent substance, as a red fluorescent substance, 3.
5MgO / 0.5MgF_Two・ GeO_Two: Mn, Mg₆A
s_TwoO₁₁: Mn, Gd_TwoO _Two: Eu, LaO_TwoS: E
u, Re as blue phosphor₁₀(PO_Four)₆Q_Two: E
u, Re₁₀(PO_Four)₆Q_Two: Eu, Mn (however, R
e is a small amount selected from Sr, Ca, Ba, Mg and Zn
At least one, Q is halogen element F, Cl, Br, I
At least one selected from BaMg)_TwoAl₁₆O
₂₇: Eu or the like can be preferably used. These fireflies
White light that can be emitted with high brightness by using a light substance
A diode can be obtained.

In the color conversion thin film layer, when these different types of fluorescent substances are mixed and arranged as one color conversion thin film layer, it is preferable that various fluorescent substances have similar central particle diameters and shapes. As a result, the light emitted from various fluorescent substances is mixed well, and color unevenness can be suppressed. Further, each fluorescent substance may be laminated as each color conversion thin film layer. When arranging the color conversion thin film layers of various fluorescent substances as multiple thin film layers, the red fluorescent substance layer, the green fluorescent substance layer, and the blue fluorescent substance layer are laminated in order in consideration of the ultraviolet light transmittance of each fluorescent substance. Preferably. In the color conversion multiple thin film layer, if the center particle diameter of each fluorescent material is set to blue fluorescent material> green fluorescent material> red fluorescent material so that the particle diameter of the fluorescent material in each layer becomes smaller from the lower layer to the upper layer, Ultraviolet light can be satisfactorily transmitted through the fluorescent material to the upper layer and converted into visible light, and leakage of ultraviolet light can be prevented. In addition, each color conversion layer may be arranged on the device so as to have a stripe shape, a lattice shape, or a triangle shape. In this way, it is preferable that the layers are arranged with a space between them, because the color mixing property is good. [Fluorescent substance] The particle size of the large particle size fluorescent substance used in the present invention is preferably in the range of 6 μm to 50 μm in the center particle size, more preferably 15 μm to 30 μm. High absorptance and conversion efficiency of light and wide excitation wavelength range. Fluorescent material smaller than 6 μm
Since aggregates are relatively easy to form and the particles are densely settled in the liquid resin and settled, the light transmission efficiency is reduced, and the light absorption rate and conversion efficiency are poor and the excitation wavelength range is narrow.

In the present invention, the particle size of the fluorescent substance is a value obtained by a volume-based particle size distribution curve, and the volume-based particle size distribution curve measures the particle size distribution of the fluorescent substance by a laser diffraction / scattering method. It can be obtained. Specifically, in an environment of a temperature of 25 ° C. and a humidity of 70%, a fluorescent substance is dispersed in an aqueous solution of sodium hexametaphosphate having a concentration of 0.05%, and a laser diffraction particle size distribution analyzer (SALD-2000A) is used. Particle size range 0.03
It is the one obtained by measuring at μm to 700 μm. In the present invention, the median particle size of the fluorescent substance is a particle size value when the integrated value is 50% in the volume-based particle size distribution curve. It is preferable that the fluorescent substance having this median particle size value is frequently contained, and the frequency value is preferably 20% to 50%. By using such a fluorescent substance having a small variation in particle size, it is possible to obtain a light-emitting device that suppresses color unevenness and has good contrast. (Yttrium / Aluminum Oxide Fluorescent Material) The fluorescent material used in the present embodiment is excited by light emitted from a semiconductor light emitting element having a nitride semiconductor as a light emitting layer to emit light, and emits cerium (Ce) or A phosphor (YAG phosphor) based on a yttrium-aluminum oxide phosphor material activated by praseodymium (Pr) can be used. As a specific yttrium / aluminum oxide-based phosphor, YAlO ₃ : C
e, Y ₃ Al ₅ O ₁₂ : Ce (YAG: Ce) or Y ₄ A
1 ₂ O ₉ : Ce, a mixture thereof, and the like. B for yttrium / aluminum oxide type phosphor
At least one of a, Sr, Mg, Ca, and Zn may be contained. Further, by containing Si, the reaction of crystal growth can be suppressed and the particles of the fluorescent substance can be aligned.

In the present specification, the yttrium-aluminum oxide fluorescent material activated with Ce is to be interpreted in a broad sense, and a part or the whole of yttrium is composed of Lu, Sc, La, Gd and Sm. Substituted with at least one element selected from the group or partially or entirely of aluminum is Ba, Tl, Ga, I
It is used in a broad sense to include a phosphor having a fluorescent effect in which any one or both of n is substituted.

More specifically, the general formula (Y _z Gd _1-z ) ₃ A
l ₅ O _12: Ce (where, 0 <z ≦ 1) photoluminescence phosphor and the general formula represented by _{(Re 1-a Sm a)} 3 Re
' ₅ O ₁₂ : Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re
Is at least one selected from Y, Gd, La, and Sc, and Re ′ is at least one selected from Al, Ga, and In. ) Is a photoluminescent phosphor. This fluorescent substance has a garnet structure,
Resistant to heat, light and moisture, the peak of the excitation spectrum is 45
It can be set to around 0 nm. In addition, the emission peak has a broad emission spectrum in the vicinity of 580 nm and a tail of 700 nm.

In addition, the photoluminescent phosphor contains Gd (gadolinium) in the crystal, and thus,
Excitation efficiency in the long wavelength region of 0 nm or more can be increased. Due to the increase in the content of Gd, the emission peak wavelength moves to the long wavelength and the entire emission wavelength also shifts to the long wavelength side. That is, when a reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence due to blue light tends to decrease. Furthermore, if desired, Ce
In addition to Tb, Cu, Ag, Au, Fe, Cr, Nd, D
It is also possible to contain y, Co, Ni, Ti, Eu and the like. Moreover, in the composition of the yttrium-aluminum-garnet-based phosphor having the garnet structure, by substituting part of Al with Ga, the emission wavelength is shifted to the short wavelength side, and part of Y of the composition is replaced with Gd. As a result, the emission wavelength can be shifted to the long wavelength side.

When a part of Y is replaced with Gd, the replacement with Gd is less than 10% and the content (replacement) of Ce is 0.0.
It is preferably from 3 to 1.0. Substitution with Gd is 2
If it is less than 50%, the green component is large and the red component is small,
By increasing the content of Ce, the red component can be supplemented, and a desired color tone can be obtained without lowering the brightness. With such a composition, the temperature characteristics are improved and the reliability of the light emitting diode can be improved. Further, by using a photoluminescent phosphor adjusted to have a large amount of red component, it is possible to form a light emitting device capable of emitting an intermediate color such as pink.

In such a photoluminescent phosphor, an oxide or a compound which easily becomes an oxide at high temperature is used as a raw material of Y, Gd, Al, and Ce, Pr, and a stoichiometric ratio of them is sufficient. To obtain the raw material. Or
A mixed raw material obtained by mixing a coprecipitated oxide obtained by firing a solution obtained by coprecipitating a solution of rare earth elements of Y, Gd, Ce, and Pr dissolved in an acid at a stoichiometric ratio with oxalic acid, and aluminum oxide. To get An appropriate amount of a fluoride such as barium fluoride or ammonium fluoride is mixed as a flux into this, packed in a crucible, and baked in the air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a baked product, and then a baked product. Can be obtained by ball-milling in water, washing, separating, drying and finally sieving.

In the light emitting diode of the present invention,
Such photoluminescent phosphors include two or more types of
Yttrium aluminum gar activated with ium
A net-based phosphor or another phosphor may be mixed. Y
Of two types of yttrium al which have different amounts of Gd to Gd
By mixing the minium garnet type phosphor,
You can easily achieve the desired color of light.
It In particular, the fluorescent substance having a large amount of substitution is used for the large particle size fluorescent substance.
As a substance, the fluorescent substance whose substitution amount is small or zero.
Is the above-mentioned medium particle size fluorescent material, the color rendering and brightness
The above can be achieved at the same time. (Nitride Phosphor) The fluorescent substance used in the present invention is N
Contains and is Be, Mg, Ca, Sr, Ba, and Zn
At least one element selected from C, Si, and G
Less selected from e, Sn, Ti, Zr, and Hf
And one kind of element, selected from rare earth elements
At least contains a nitride-based phosphor activated with one element
Can be made. Also used in this embodiment
As a nitride-based phosphor, visible light emitted from the light-emitting element
Absorbs light, ultraviolet rays, or light emitted from YAG phosphors
It means a phosphor that is excited to emit light. In particular
The phosphor according to the present invention is Sr-Ca- to which Mn is added.
Si-N: Eu, Ca-Si-N: Eu, Sr-Si-
N: Eu, Sr-Ca-Si-O-N: Eu, Ca-S
i-O-N: Eu, Sr-Si-O-N: Eu-based silicon
It's a night ride. The basic constituent elements of this phosphor are
General formula L_XSi_YN_{(2 / 3X + 4 / 3Y)}: Eu young
Kuha L_XSi _YO_ZN
_{(2 / 3X + 4 / 3Y-2 / 3Z)}: Eu (L is S
Any of r, Ca, Sr and Ca. ). General
In the formula, X and Y are X = 2, Y = 5 or X = 1, Y =
It is preferably 7, but any can be used.
Specifically, Mn was added to the basic constituent elements (Sr
_XCa_1-X)_TwoSi₅N₈: Eu, Sr_TwoSi
₅N₈: Eu, Ca_TwoSi₅N₈: Eu, Sr_XCa
_1-XSi₇N₁₀: Eu, SrSi₇N₁₀: Eu,
CaSi₇N₁₀: Use a phosphor represented by Eu
Is preferable, but Mg, S
r, Ca, Ba, Zn, B, Al, Cu, Mn, Cr and
And at least one selected from the group consisting of Ni
It may be included. However, the present invention is not limited to this embodiment.
And not limited to the examples. L is Sr, Ca, Sr
Either of Ca. Sr and Ca are mixed if desired
You can change the ratio. Si is used for the composition of the phosphor
To provide a phosphor that is inexpensive and has good crystallinity
You can

Europium Eu, which is a rare earth element, is used as the emission center. Europium mainly has divalent and trivalent energy levels. The phosphor of the present invention uses Eu ²⁺ as an activator with respect to the matrix alkaline earth metal-based silicon nitride. Eu ²⁺ is easily oxidized and trivalent Eu ₂
It is commercially available with a composition of O ₃ . However, commercially available Eu ₂ O
_In No. ₃ , O is largely involved and it is difficult to obtain a good phosphor. Therefore, it is preferable to use Eu ₂ O ₃ after removing O from the system. For example, it is preferable to use europium simple substance or europium nitride. However, this is not the case when Mn is added.

Mn, which is an additive, promotes the diffusion of Eu ²⁺ and improves the luminous efficiency such as luminous brightness, energy efficiency and quantum efficiency. Mn is contained in the raw material, or is contained in the raw material during the manufacturing process, or is burned together with the raw material. However, Mn is not contained in the basic constituent elements after firing, or even if it is contained, only a small amount remains as compared with the initial content. This is probably because Mn was scattered during the firing process. The phosphor contains Mg, Sr, Ca, Ba, Zn, B in the basic constituent elements or together with the basic constituent elements.
It contains at least one selected from the group consisting of Al, Cu, Mn, Cr, O and Ni. These elements have actions such as increasing the particle size and increasing the emission brightness. Also, B, Al, Mg, Cr and N
i has an effect of suppressing afterglow.

Such a nitride-based phosphor absorbs part of the blue light emitted by the light emitting element and emits light in the yellow to red region. The nitride-based phosphor is used together with the YAG-based phosphor in the light-emitting device having the above-described structure, and the blue light emitted by the light-emitting element and the yellow to red light emitted from the nitride-based phosphor are mixed to produce a warm color system. A light emitting device that emits white light is obtained. The phosphor added in addition to the nitride-based phosphor preferably contains a yttrium-aluminum oxide phosphor which is activated by cerium. This is because the chromaticity can be adjusted to a desired level by containing the yttrium aluminum oxide fluorescent substance. The cerium-activated yttrium-aluminum oxide phosphor absorbs part of the blue light emitted by the light-emitting element and emits light in the yellow region. Here, the blue light emitted by the light emitting element and the yellow light of the yttrium-aluminum oxide fluorescent substance are mixed to emit a pale white color. Therefore, the yttrium aluminum oxide phosphor and the phosphor that emits red light are mixed together in the color conversion layer, and the blue light emitted by the light emitting element is combined to emit white mixed light. A light emitting device can be provided. Particularly preferred is
It is a white light emitting device whose chromaticity is located on the locus of black body radiation in the chromaticity diagram. However, in order to provide a light emitting device having a desired color temperature, the amount of phosphor of the yttrium-aluminum oxide phosphor and the amount of phosphor of red light emission can be appropriately changed. The light-emitting device that emits white-color mixed light is attempting to improve the special color rendering index R9. A conventional light emitting device that emits white light only by combining a light emitting element that emits blue light and a yttrium aluminum oxide fluorescent material activated by cerium has a color temperature Tcp = 460.
In the vicinity of 0K, the special color rendering index R9 is close to 0,
The redness component was insufficient. Therefore, special color rendering index R9
However, in the present invention, the color temperature Tcp = 4 can be obtained by using the red light emitting phosphor together with the yttrium aluminum oxide phosphor.
The special color rendering index R9 can be increased to around 40 at around 600K.

Next, the phosphor ((Sr _X Ca
_The method for producing _1-X ) ₂ Si ₅ N ₈ : Eu) will be described, but the present invention is not limited thereto. The above phosphor contains M
It contains n and O.

The raw materials Sr and Ca are crushed. Raw material S
R and Ca are preferably used alone, but compounds such as imide compounds and amide compounds can also be used. The raw materials Sr and Ca include B, Al, Cu and M.
It may contain g, Mn, Al ₂ O ₃ , or the like. The raw materials Sr and Ca are pulverized in a glove box in an argon atmosphere. Sr and Ca obtained by crushing are
The average particle size is preferably about 0.1 μm to 15 μm, but is not limited to this range. The purity of Sr and Ca is preferably 2N or more, but not limited to this. Metal Ca, metal S for better mixing
It is also possible to use at least one or more of r and metal Eu as an alloy material after nitriding and crushing.

The raw material Si is crushed. The raw material Si is
It is preferable to use a simple substance, but it is also possible to use a nitride compound, an imide compound, an amide compound, or the like.
For example, Si ₃ N ₄ , Si (NH ₂ ) ₂ , Mg ₂ Si, or the like. Although the purity of the raw material Si is preferably 3N or more, Al ₂ O ₃ , Mg, metal boride (Co ₃ B,
Ni ₃ B, CrB), manganese oxide, H ₃ BO ₃ , B ₂
Compounds such as O ₃ , Cu ₂ O and CuO may be contained. Si is crushed in a glove box in an argon atmosphere or a nitrogen atmosphere, similarly to the raw materials Sr and Ca. The average particle size of the Si compound is about 0.1 μ
It is preferably m to 15 μm.

Next, the raw materials Sr and Ca are nitrided in a nitrogen atmosphere. The reaction formulas are shown in the following formulas 1 and 2, respectively.

3Sr + N ₂ → Sr ₃ N ₂ ... (Equation 1) 3Ca + N ₂ → Ca ₃ N ₂ ... (Equation 2) Sr and Ca are added in a nitrogen atmosphere at 600 to 900 ° C. 5
Nitriding for hours. Sr and Ca may be mixed and nitrided, or may be individually nitrided. This allows S
A nitride of r and Ca can be obtained. The Sr and Ca nitrides are preferably highly pure, but commercially available ones can also be used.

The raw material Si is nitrided in a nitrogen atmosphere. This reaction formula is shown in Formula 3 below.

3Si + 2N ₂ → Si ₃ N ₄ (Formula 3) Silicon Si is also nitrided in a nitrogen atmosphere at 800 to 1200 ° C. for about 5 hours. Thereby, silicon nitride is obtained. The silicon nitride used in the present invention is preferably highly pure, but commercially available ones can also be used.

The Sr, Ca or Sr-Ca nitride is crushed. A nitride of Sr, Ca, and Sr-Ca is crushed in a glove box in an argon atmosphere or a nitrogen atmosphere. Similarly, Si nitride is crushed. Similarly, the Eu compound Eu ₂ O ₃ is pulverized. As the compound of Eu, europium oxide is used, but metal europium, europium nitride and the like can also be used. In addition, as the raw material Z, an imide compound or an amide compound can be used. Europium oxide is
A high-purity product is preferable, but a commercially available product can also be used. The average particle size of the crushed alkaline earth metal nitride, silicon nitride and europium oxide is about 0.1 μm.
To 15 μm is preferable.

Among the above raw materials, Mg, Sr, Ca, B
At least one selected from the group consisting of a, Zn, B, Al, Cu, Mn, Cr, O and Ni may be contained. Further, the above elements such as Mg, Zn and B can be mixed by adjusting the blending amount in the following mixing step. These compounds can be added to the raw materials alone, but are usually added in the form of compounds. This class of _{compounds, H 3 BO 3, Cu 2} O 3, MgC
l ₂ , MgO · CaO, Al ₂ O ₃ , metal boride (C
rB, Mg ₃ B ₂ , AlB ₂ , MnB), B ₂ O ₃ , C
Examples include u ₂ O and CuO.

After the above pulverization, Sr, Ca, Sr
-Ca nitride, Si nitride, Eu compound Eu ₂ O
Mix ₃ and add Mn. Since these mixtures are easily oxidized, in an Ar atmosphere or a nitrogen atmosphere,
Mix in the glove box.

Finally, a mixture of Sr, Ca, Sr-Ca nitride, Si nitride and Eu compound Eu ₂ O ₃ is fired in an ammonia atmosphere. Firing the, Mn is added _{(Sr X Ca 1-X)} 2 Si 5 N 8: it is possible to obtain a phosphor represented by Eu. However, the composition of the intended phosphor can be changed by changing the blending ratio of each raw material.

For the firing, a tubular furnace, a small furnace, a high frequency furnace, a metal furnace or the like can be used. The firing temperature is 120
Although firing can be performed in the range of 0 to 1700 ° C,
A firing temperature of 1400 to 1700 ° C is preferred. For the firing, it is preferable to use one-step firing in which the temperature is gradually raised and the firing is performed at 1200 to 1500 ° C. for several hours.
It is also possible to use a two-stage firing (multi-stage firing) in which the first-stage firing is performed at 00 to 1000 ° C., and the second stage is fired at 1200 to 1500 ° C. by gradually heating. The phosphor raw material is preferably fired using a crucible made of boron nitride (BN) or a boat. Besides the crucible made of boron nitride, a crucible made of alumina (Al ₂ O ₃ ) can be used.

By using the above manufacturing method, it is possible to obtain the desired phosphor.

In the present embodiment, a nitride-based phosphor is particularly used as the phosphor that emits reddish light. In the present invention, the YAG-based phosphor and the red-based light described above are used. A light emitting device including a phosphor capable of emitting light can also be used. Such a phosphor that can emit red light is a phosphor that is excited by light having a wavelength of 400 to 600 nm to emit light, and is, for example, Y ₂ O ₂ S: E.
u, La ₂ O ₂ S: Eu, CaS: Eu, SrS: E
u, ZnS: Mn, ZnCdS: Ag, Al, ZnCd
S: Cu, Al, etc. are mentioned. As described above, the color rendering of the light emitting device can be improved by using the phosphor capable of emitting red light together with the YAG phosphor.

The YAG phosphors and the phosphors capable of emitting red light represented by the nitride phosphors formed as described above are composed of a single layer of color conversion on the side end face of the light emitting element. Two or more types may be present in the layer, or one type or two or more types may be present in the color conversion layer composed of two layers. With such a configuration, mixed color light can be obtained by mixing colors of light from different types of phosphors. In this case, it is preferable that the average particle diameter and the shape of the respective phosphors are similar in order to mix the light emitted from the respective phosphors better and reduce the color unevenness. Further, in consideration of the fact that the nitride-based phosphor absorbs a part of the light whose wavelength is converted by the YAG phosphor, the nitride-based phosphor is YA
It is preferable to form the color conversion layer so that the color conversion layer is located closer to the side end face of the light emitting element than the G-based phosphor. Furthermore, it is preferable to form the color conversion layer so that the nitride-based phosphor is located closer to the anisotropic conductive layer than the YAG-based phosphor. With this configuration, a part of the light whose wavelength has been converted by the YAG phosphor is not absorbed by the nitride phosphor, and the YAG phosphor and the nitride phosphor are mixed. It is possible to improve the color rendering of the mixed color light by both phosphors, as compared with the case where the phosphors are contained in the color conversion layer. [Filler] Further, in the present invention, a filler may be contained in the color conversion layer in addition to the fluorescent substance. The specific material is the same as that of the diffusing agent, but the central particle size is different from that of the diffusing agent, and in this specification, the filler means a material having a central particle size of 5 μm or more and 100 μm or less. When a filler having such a particle size is contained in the translucent resin, the chromaticity variation of the light emitting device is improved by the light scattering action, and the thermal shock resistance of the translucent resin can be enhanced. The filler preferably has a particle size and / or shape similar to that of the fluorescent substance. Here, in the present specification, the similar particle size refers to a case where the difference between the center particle sizes of the particles is less than 20%, and the similar shape refers to the degree of approximation of the perfect circle of each particle size. It refers to a case where the difference in the value of circularity (circularity = perimeter of a perfect circle equal to the projected area of a particle / perimeter of a projected particle) is less than 20%. By using such a filler, the fluorescent substance and the filler interact with each other, and the fluorescent substance can be favorably dispersed in the resin, and color unevenness is suppressed. Further, both the fluorescent substance and the filler have a central particle diameter of 15 μm.
˜50 μm, more preferably 20 μm to 50 μm, and by adjusting the particle size in this way, it is possible to arrange the particles with a preferred interval. As a result, a light extraction path is secured, and it is possible to improve the directional characteristics while suppressing a decrease in luminous intensity due to the inclusion of filler. Further, when a sealing material is formed by a stencil printing method in which a fluorescent material and a filler having such a particle size range are contained in a translucent resin, the clogging of the dicing blade is recovered in the dicing step after the sealing member is cured. A dresser effect can be brought about and mass productivity is improved. [Light Diffusing Layer 7] Further, a light transmissive member may be provided on one plane composed of the surface of the light emitting element and the color conversion layer disposed on the side end surface of the light emitting element in order to increase the light transmittance. A light diffusing layer 7 having a diffusing agent capable of reflecting and scattering light from a light emitting element and light from a fluorescent substance in the translucent member.
May be provided. In this case, if the heights of the light emitting element surface and the color conversion layer surface are substantially parallel to each other, a light diffusing layer having a uniform film thickness can be easily formed, and good color mixing properties can be obtained, which is preferable. The light diffusion layer can be formed by various conventional methods such as potting, spray coating and stencil printing.

In the present invention, the diffusing agent is not particularly limited, and various ones such as barium titanate, barium sulfate, titanium oxide, aluminum oxide, silicon oxide, light calcium carbonate and heavy calcium carbonate can be used.
The median particle diameter of the diffusing agent is preferably 1.0 μm or more and less than 5 μm, more preferably 1.0 μm or more and less than 2.5 μm, and light is emitted when the diffusing agent having the above-mentioned particle diameter value is used. Light from the device and the fluorescent substance is preferably diffusely reflected, and color unevenness can be suppressed, which is preferable. Further, when the diffusing agent is of the crushed type, the long side length measured by a transmission electron microscope is preferably 1.0 μm or more and less than 3.0 μm.
The content of the diffusing agent is preferably 0.5 parts by weight or more and 5 parts by weight or less based on 100 parts by weight of the translucent member. As a result, the luminous intensity and reliability of the light emitting device can be improved without reducing the light extraction efficiency from the light emitting element and the fluorescent material. In addition, the half width of the emission spectrum can be narrowed, and a light emitting device with high color purity can be obtained.
The refractive index of the transparent member is preferably 1.4 or more and 1.65 or less, and the refractive index of the diffusing agent is preferably higher than that of the transparent member. As a result, a surface-emitting light-emitting device having excellent color mixing properties in which light is well reflected and scattered by the diffusing agent can be obtained.

The translucent member which is a constituent member of the light diffusion layer is
Like the color conversion layer, it can have both organic and inorganic substances, depending on the characteristics and application of the light emitting element to be used, and epoxy resin, acrylic resin, urethane resin, diallyl phthalate resin, silicone resin, glass, etc. are preferable. Used for.

Among the organic materials, as a member having a relatively high light resistance, a translucent polymer resin having a hydrophilic main chain and a hydrophobic side chain can be mentioned. The translucent polymer resin having a hydrophilic main chain and a hydrophobic main chain does not cure and shrink due to heat and has tackiness on the surface after curing, which makes it extremely difficult to handle.

For example, when the translucent polymer resin is applied to the inside of the package as in the present embodiment, the filling amount is adjusted so as to fill up to the line inside the uppermost surface of the package. The surface tends to be uneven, resulting in uneven color and variations in directional characteristics. Further, it is difficult to make the injection amount of the polymer resin constant in each light emitting device, the diffusing agent cannot be uniformly arranged in the polymer resin, and color variation is observed between the light emitting devices.

Therefore, in the present embodiment, a light-diffusing layer is formed by combining a light-transmitting polymer resin having a hydrophilic main chain and a hydrophobic side chain with a diffusing agent capable of adjusting the oil absorption amount. The diffusion layer having such a configuration can be solidified with a film thickness thinner than that in the coating step by curing the liquid layer in the coating step by heat. Specifically, when the liquid mixture is filled up to the uppermost surface of the package recess and heat-cured, the resulting light diffusion layer is contained inside the package and has a shape having a smooth parabolic recess from the end to the center. . This makes it possible to easily form a highly reliable light diffusion layer without finely adjusting the filling amount in the coating step. This effect is probably that the ratio of the oil absorption amount of the diffusing agent is promoted by the heating and curing step of the resin, and a part of the components in the resin is absorbed by the diffusing agent, while the resin absorption rate of the diffusing agent is Is higher than the rate of increase in volume due to absorption, and as a result, the volume of the diffusion layer is believed to decrease overall.

The oil absorption of the diffusing agent can be adjusted by the degree of surface treatment. Surface treatment is Al
It can be performed using ₂ O ₃ , Fe ₂ O ₃ , Si or the like. When it is desired to greatly reduce the volume, it is preferable to use it in a state where almost no surface treatment is performed. The greater the degree of surface treatment, the smaller the oil absorption of the diffusing agent. By adjusting the degree of surface treatment of the diffusing agent in this way, a light diffusing layer having a desired thickness can be easily formed. Examples of such a diffusing agent whose oil absorption can be adjusted include light calcium carbonate, heavy calcium carbonate, talc, white carbon, magnesium carbonate, and hydrous aluminum-magnesium silicate. Also, the oil absorption of the diffusing agent is 30 ml without surface treatment.
/ 100 g or more and 150 ml / 100 g or less is preferable. As a result, a wide range of oil absorption can be set by performing surface treatment later. In the present specification, the oil absorption amount is a value measured by the oil absorption amount test method of Japanese Industrial Standard (JIS K5101).

The light diffusing layer composed of a light-transmitting polymer resin having a hydrophilic main chain and a hydrophobic side chain and a diffusing agent having an adjustable oil absorption amount is formed from the both ends to the central part formed by resin absorption of the diffusing agent. Since it has a smooth light emitting surface that is concavely parabolic, it is possible to realize a surface light source that emits light uniformly. Furthermore, it is preferable that the degree of depression of the light emitting surface as viewed from the light emitting surface side is substantially bilaterally symmetrical with respect to the major axis and the minor axis, whereby a light emitting device having good directional characteristics can be obtained. Such a curved light emitting surface is formed by, for example, a stencil printing method.

As described above, the light diffusion layer of this embodiment is
Since a light diffusion layer consisting of a translucent polymer resin consisting of a hydrophilic main chain and a hydrophobic side chain and a diffusing agent whose oil absorption can be adjusted is used, the filling amount does not need to be finely adjusted by the appearance, and the filling amount is packaged. It may be filled in the same plane line as the upper surface. With this, even though the surface after curing has tackiness, it can be formed by various conventionally known methods like other translucent members.

[0065]

EXAMPLES Examples of the present invention will be described below. The present invention is not limited to the examples shown below. Example 1 A surface mount type light emitting device as shown in FIG. 1 is formed. The LED chip, which is a light emitting element, has an In layer with a monochromatic emission peak of 475 nm which is visible light as a light emitting layer.
A nitride semiconductor device having a _0.2 Ga _0.8 N semiconductor is used. More specifically, in the LED chip, TMG (trimethylgallium) gas, TMI (trimethylindium) gas, nitrogen gas and dopant gas are caused to flow together with a carrier gas on a cleaned sapphire substrate, and MOCV is used.
It can be formed by forming a nitride semiconductor by the D method. SiH ₄ and Cp ₂ as dopant gases
By switching Mg, a layer to be an n-type nitride semiconductor or a p-type nitride semiconductor is formed.

As an element structure of the LED chip, an n-type G that is an undoped nitride semiconductor is formed on a sapphire substrate.
An aN layer, a GaN layer that is an n-type contact layer formed with a Si-doped n-type electrode, an n-type GaN layer that is an undoped nitride semiconductor, and a G that is a barrier layer that constitutes a light emitting layer next.
InGa sandwiched between GaN layers with aN layer, an InGaN layer forming a well layer, and a GaN layer forming a barrier layer as one set
This is a multiple quantum well structure in which five N layers are stacked. A Mg-doped p-type cladding layer A was formed on the light emitting layer.
The lGaN layer and the GaN layer, which is a p-type contact layer doped with Mg, are sequentially stacked. (Note that
A GaN layer is formed on a sapphire substrate at a low temperature to serve as a buffer layer. In addition, the p-type semiconductor is 400
Annealed above ℃. Next, the surface of each pn contact layer is exposed on the same side of the nitride semiconductor on the sapphire substrate by etching. Positive and negative pedestal electrodes were formed on each contact layer by a sputtering method. A metal thin film is formed on the entire surface of the p-type nitride semiconductor as a transparent electrode, and then a pedestal electrode is formed on a part of the transparent electrode. After the scribe line is drawn on the finished semiconductor wafer, it is divided by an external force to form an LED chip having a pair of positive and negative electrodes on the semiconductor laminated surface side and capable of emitting a part of light emission from the side end surface. .

Next, the molding resin melted is poured from a gate on the lower surface side of the package molded body into a mold which is closed by inserting a pair of positive and negative lead electrodes, and cured to form a package. To do. The package has a recess capable of accommodating a light emitting element, and positive and negative lead electrodes are integrally molded from the bottom surface of the recess so that one main surface is exposed. In this package, the outer lead portions of the positive and negative lead electrodes are bent inward at both ends of the joint surface of the package along the joint surface, and are soldered at the inner bent portions. Is configured.

Next, a Ni thin film was formed on the spherical plastic particles having a central particle diameter of 3 μm by electroless plating, and then an Au thin film was formed on the outermost layer by displacement plating. 5% by volume of conductive particles is added, and the film thickness is 1 so as to cover the bottom surface of the recess of the package.
It is applied so as to be in the range of 0 μm or more and 20 μm or less. Next, the respective electrodes of the LED chip are made to face each other on the respective lead electrodes exposed from the bottom surface of the package recess so that the electrode forming surface and the side end surface of the LED chip are partially embedded in the above coating liquid. Then, the anisotropic conductive layer is solidified by applying heat and pressure, and each electrode is electrically connected.

Next, the fluorescent substances are Y, Gd, Al, and
Mixing Ce oxides by stoichiometric ratio
Get the raw materials. Flux is mixed with this and packed in a crucible,
Mix for 2 hours in a ball mill mixer. Remove the ball
Temperature, 1400 ° C to 1600 ° C in a weak reducing atmosphere for 6
Baking for 1 hour, then 1400 ° C to 1600 ° C in a reducing atmosphere
Bake for 6 hours. Ball mill the baked product in water,
Wash, separate, dry, and finally pass through a sieve to obtain a median particle size of 8 μm
Is (Y_0.8Gd_0.2)_2.750Al
₅O₁₂: Ce_0.250Form a fluorescent material.

150 parts by weight of the above fluorescent material was added to 100 parts by weight of a silicone resin, in contact with the upper surface of the anisotropic conductive layer and the lateral end surface of the LED chip,
The LED chip is filled up to almost the same line as the uppermost surface with a substantially uniform film thickness, 50 ° C. × 2 hours, and 150 ° C.
Heat treatment is performed for 4 hours to form a color conversion layer.

Next, based on 100 parts by weight of the silicone resin, the central particle diameter is 3 μm, the degree of aggregation is 93%, and the oil absorption is 70 ml / 1.
Include 3 parts by weight of light calcium carbonate, which is 00 g,
Stir for 5 minutes with a spinning revolution mixer. Next, in order to cool the heat generated by the stirring process, the resin is allowed to stand for 30 minutes to return it to a constant temperature for stabilization. The mixed solution thus obtained is filled in the package recess up to the same plane as the upper surfaces of both ends of the recess. Finally, heat treatment is performed at 50 ° C. for 2 hours and 150 ° C. for 4 hours. As a result, a light-emitting surface having a parabolic recess that is substantially symmetrical from the upper surface of both ends of the recess to the center is obtained.

In the light emitting diode thus formed, the blue light emitted from the upper surface of the LED chip is radiated to the front with high output, and a part of the light emitted from the side end surface of the LED chip is adjacent. The remaining portion of the light directly incident on the color conversion layer and emitted from the lateral end face is guided to the adjacent anisotropic conductive film, reflected and scattered by the conductive particles contained therein, and then laminated on top. Incident on the color conversion layer. This makes it possible to efficiently irradiate all the fluorescent substances with the excitation light, and the yellow light emitted from the fluorescent substances is emitted forward from the color conversion layer. These blue light and yellow light are mixed well in the front light diffusion layer, and white light appears in the front.

As described above, in the light emitting device of this example, since the light emitted from all sides of the light emitting element is efficiently utilized, it is possible to obtain a high output light having a high light transmittance. Further, by making the translucent member used for each member the same material, it is possible to increase the light transmittance and reliability at the interface between the members. The color conversion type light emitting device thus obtained has a luminous intensity of 500 mc.
d, the optical output is 4 mW, and good directional characteristics can be obtained.
Further, in the high temperature storage test (100 ° C.), the high temperature and high humidity storage test (80 ° C., 85% RH), and the low temperature storage test (−40 ° C.), almost no decrease in output was observed, and it can be said that it has high reliability. . Further, 3σ of the chromaticity in the x-axis direction on the CIE chromaticity coordinate is 0.006, and a light emitting device with very little color variation can be obtained. (Embodiment 2) As shown in FIG. 2, when an integrated light emitting device is formed in the same manner as in Embodiment 1 except that a plurality of light emitting elements are mounted with the color conversion layer interposed therebetween, the color mixing property is further excellent. A light emitting device capable of emitting light with high output is obtained. (Embodiment 3) An integrated light emitting device is formed in the same manner as in Embodiment 2 except that an LED array light emitting element having a plurality of light emitting layers is used as each light emitting element as shown in FIG.
The same effect as can be obtained.

[0074]

According to the light emitting device of the present invention, the color conversion layer is provided in contact with the upper side end face of the light emitting element, and the anisotropic conductive layer is provided in contact with the lower side face of the light emitting element to emit light from the side end face. The efficiency of the fluorescent substance in the color conversion layer is increased by irradiating the generated excitation light from two directions of the lateral end surface and the lower bottom surface of the color conversion layer. Furthermore, by disposing the color conversion layer on the upper surface of the light emitting element and providing the color conversion layer only on the side surface on the side of the light emitting element, the arrangement pattern of the fluorescent material can be made constant, and the phosphors can be arranged uniformly. It is possible to suppress the color variation and to extract the light emitted from the light emitting element and the light emitted from the color conversion layer upward with high output. In addition, a continuous light diffusion which is in contact with the upper surface of the light emitting element and the upper surface of the color conversion layer and includes a highly reliable polymer resin having a hydrophilic main chain and a hydrophobic main chain and a diffusing agent capable of adjusting an oil absorption rate. By providing layers,
The light emitting surface may be a smooth surface having a recess from the end to the center. As a result, the work in the coating step can be simplified and a uniform surface light source can be obtained. Further, it is possible to realize a light emitting device that can mount a plurality of light emitting elements with high density and high reliability, and that has a long life and can emit light with brightness equivalent to that of lighting.

[Brief description of drawings]

FIG. 1 is a schematic plan view and a schematic cross-sectional view showing a light emitting device of the present invention.

FIG. 2 is a schematic plan view and a schematic cross-sectional view showing another light emitting device of the present invention.

FIG. 3 is a schematic plan view and a schematic cross-sectional view showing another light emitting device of the present invention.

[Explanation of symbols]

1 ... Package 2, 3 ... External electrodes 4 ... Anisotropic conductive layer 4a ... conductive particles 5 ... Light emitting element 6 ... Color conversion layer 7 ... Light diffusion layer

Claims (5)

[Claims] 1. A light emitting element having a pair of positive and negative electrodes on the same surface side and capable of emitting a part of light emission from a side end surface, and a light emitting element which absorbs a part of the light of the light emitting element and emits different wavelengths. A color conversion layer having a fluorescent substance capable of emitting light having, and a light emitting device having a light emitting device, wherein the light emitting element has a surface having an external electrode on a surface,
It is flip-chip mounted via an anisotropic conductive layer comprising conductive particles, the color conversion layer is laminated in contact with the anisotropic conductive layer extending around the light emitting element, The light emitting device is characterized in that one side of the side end face of the light emitting element in the thickness direction is covered with the anisotropic conductive layer and the other side thereof is covered with the color conversion layer. 2. The color conversion layer has a shape that rises vertically from the top surface of the anisotropic conductive layer with a substantially uniform thickness, and the fluorescent material is 30 parts by weight with respect to 100 parts by weight of the translucent member. 2. The light emitting device according to claim 1, wherein the light emitting device is contained in an amount of 100 parts by weight to 100 parts by weight. 3. The surface of the color conversion layer is substantially parallel to the surface of the light emitting device, and has a continuous diffusion layer in contact with the light emitting device exposed surface and the color conversion layer exposed surface. The light emitting device according to claim 2, wherein: 4. A plurality of the light emitting elements are mounted with the color conversion layer sandwiched therebetween.
The light-emitting device according to. 5. The light emitting device is an array light emitting device having a plurality of light emitting layers.
The light-emitting device according to.