JP2014116598A - Light emitting diode sealing composition, phosphor sheet, led package employing the same and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve luminance of an LED package employing a light emitting diode sealing composition to which fine particles are added.SOLUTION: A light emitting diode sealing composition contains a matrix resin, a phosphor and a plurality of fine particles having different refraction indices. A concentration of fine particles having a refraction index closest to that of the matrix resin, among the fine particles, in a solid component in the sealing composition is 1 to 30 vol%, and a concentration of the other fine particles in the solid component in the sealing composition is 0.001 to 0.045 vol%.

Description

  The present invention relates to a composition for sealing a light emitting diode, a phosphor sheet, an LED package using them, and a method for producing the same.

  Light-emitting diodes (LEDs) are rapidly expanding in the field of liquid crystal display (LCD) backlights and special lighting fields with low power consumption, long service life, and design, etc. due to the remarkable improvement in luminous efficiency. doing. Furthermore, by further improving the luminous efficiency, it is expected to form a huge market in the general lighting field in the future, characterized by the low environmental load as described above.

  Since the emission spectrum of the LED depends on the semiconductor material forming the LED chip, in order to obtain white light for an LCD backlight or general illumination, a phosphor corresponding to each chip is installed on the LED chip. For example, a method of installing a yellow phosphor on a blue LED chip, a method of installing red and green phosphors on a blue LED chip, and a red, green and blue fluorescence on an LED chip emitting ultraviolet light. There are ways to install the body. From the viewpoint of luminous efficiency and cost of the LED chip, a method of installing a yellow phosphor on a blue LED chip or a method of installing red and green phosphors is currently most widely adopted.

  As one of the methods for installing the phosphor on the LED chip, a resin composition in which phosphor particles are dispersed is formed on the chip, and then a silicone-based resin having high transparency, good heat resistance and light resistance. The method of sealing with resin is performed. However, since it is difficult to keep the phosphor particles uniformly dispersed, the amount of phosphors to be installed often differs in the step of applying the phosphor on the LED chip. As a result, luminance variation and chromaticity variation for each LED package were likely to occur.

In order to improve the dispersibility of the phosphor particles in the resin, for example, Patent Documents 1 and 2 discuss the dispersion of silicone fine particles in the resin for the purpose of preventing the phosphor from settling. Patent Document 3, 1/10 or more at which silicon oxide having an average particle diameter D average particle diameter D ₅₀ value of the phosphor ₅₀ as a dispersant, aluminum oxide, epoxy resin, barium sulfate, calcium carbonate, barium oxide Titanium oxide has been studied.

  The addition of these fine particles is not intended to prevent the sedimentation of the phosphor, but it is also considered to be used for controlling light scattering and improving mechanical properties such as crack resistance of the sealing composition. For example, Patent Document 4 includes a silicone-based fine particle, shows a good light extraction efficiency by controlling the ratio of the linear light transmittance and the total light transmittance at a wavelength of 400 nm, and exhibits a light diffusion effect. It has been considered to control. Patent Document 5 discusses suppression of luminance non-uniformity due to observation angles by containing silicone fine particles. In Patent Documents 6 and 7, it is studied to improve molding processability, transparency, heat resistance, adhesion, crack resistance, cold shock resistance, etc. by using silicone fine particles as one of the essential components. Yes.

International Publication No. 2011/102272 JP 2006-339581 A Japanese Patent Laying-Open No. 2005-064233 JP 2010-276855 A JP 2008-159713 A JP 2010-095619 A JP 2006-321832 A

  By including the phosphor and fine particles in the matrix resin as described above, it is possible to suppress the sedimentation of the phosphor due to the density difference between the phosphor and the matrix resin. However, when fine particles are added, although luminance variation and chromaticity variation can be reduced or mechanical properties can be improved as compared with a case where fine particles are not added, there is a problem that luminance is lowered.

  As a result of further detailed examination, when matrix resin and fine particles having a close refractive index are used, blue light with low visibility from the LED chip is not absorbed by the phosphor and easily leaks to the outside. It turned out that there was a tendency. On the other hand, it was found that when matrix resin and fine particles having different refractive indexes were used, the reabsorption loss of the phosphor increased due to light scattering in the sealing resin, and the luminance tended to decrease.

  The present invention focuses on the above-mentioned problems and aims to improve the luminance of an LED package using a light-emitting diode sealing composition to which fine particles are added.

  The present invention relates to a composition for sealing a light-emitting diode comprising a matrix resin, a phosphor, and a plurality of fine particles having different refractive indexes, the fine particles having a refractive index closest to the refractive index of the matrix resin among the fine particles. Is a concentration of 1 to 30 vol% in the solid content of the sealing composition, and other light emission is a concentration of 0.001 to 0.045 vol% in the solid content of the sealing composition A composition for encapsulating a diode.

  The composition for encapsulating a light emitting diode of the present invention can improve luminance while suppressing variation in luminance and chromaticity of the light emitting diode.

The measuring apparatus used in Examples 1-5 and Comparative Examples 1-5. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 2 and the increase rate of illumination intensity in Examples 1-3 and Comparative Examples 1-3. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 3 and the increase rate of illumination intensity in Examples 4-5 and Comparative Examples 1 and 4-5. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 4 and the increase rate of illumination intensity in Examples 6-9 and Comparative Examples 1, 6, and 7. FIG. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 5 and the increase rate of illumination intensity in Examples 10-13 and Comparative Examples 1, 8, and 9. FIG. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 5 in the sealing material 2 in Examples 14-17 and Comparative Examples 1, 10, and 11, and the increase rate of illumination intensity. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 2 and the increase rate of a brightness | luminance in Examples 18-23 and Comparative Examples 12-14. It is a graph which shows the relationship between the density | concentration of the microparticles | fine-particles 2 and the increase rate of a brightness | luminance in Examples 24-29 and Comparative Examples 15-17.

  The present invention relates to a composition for sealing a light-emitting diode comprising a matrix resin, a phosphor, and a plurality of fine particles having different refractive indexes, the fine particles having a refractive index closest to the refractive index of the matrix resin among the fine particles. Is a concentration of 1 to 30 vol% in the solid content of the sealing composition, and other light emission is a concentration of 0.001 to 0.045 vol% in the solid content of the sealing composition A composition for encapsulating a diode. Fine particles with a refractive index close to that of the matrix resin have the effect of suppressing the sedimentation of the phosphor, and fine particles with a refractive index significantly different from that of the matrix resin have an appropriate light scattering effect, thereby suppressing the luminance variation and chromaticity variation of the light emitting diode. , The brightness can be improved.

  The matrix resin forms a continuous phase in the encapsulating composition, and can be an epoxy resin, silicone resin (silicone rubber, silicone) as long as it is a material excellent in molding processability, transparency, heat resistance, adhesiveness, and the like. Known resins such as gels and other organopolysiloxane cured products (including crosslinked products), urea resins, fluororesins, and polycarbonate resins can be used, and silicone resins can be preferably used. For example, an addition reaction curable silicone composition is heated and cured at room temperature or a temperature of 50 to 200 ° C., and is excellent in transparency, heat resistance, and adhesiveness. As the addition reaction curable silicone, a silicone containing an alkenyl group bonded to a silicon atom, a silicone having a hydrogen atom bonded to a silicon atom, and a catalytic amount of a platinum-based catalyst can be used.

  The phosphor absorbs light emitted from the LED chip, performs wavelength conversion, and emits light having a wavelength different from that of the light emitting element. Thereby, a part of the light emitted from the LED chip and a part of the light emitted from the phosphor can be mixed to produce a multicolor LED including white. Specifically, a white LED can be emitted with a single LED chip by optically combining a blue LED with a fluorescent substance that emits a yellow emission color by light from the LED. Further, even when a fluorescent material that emits green and red light emission colors is optically coupled to a blue LED by light from the LED, a white LED can be emitted using a single LED chip. A well-known thing can be used for the above-mentioned fluorescent substance. Examples of phosphors corresponding to blue LED chips include YAG phosphors, TAG phosphors, silicate phosphors, nitride phosphors, oxynitride phosphors, and the like.

  As the fine particles having different refractive indexes, either inorganic fine particles or organic fine particles can be used. For example, inorganic fine particles include crystalline or amorphous silica, alumina, zirconia, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, glass fiber, alumina fiber, talc, water Examples thereof include aluminum oxide, calcium carbonate, manganese carbonate, barium sulfate, potassium titanate, calcium silicate, barium fluoride, and the like. These may be used alone or in combination of two or more. Alumina is preferred from the viewpoints of refractive index and availability. In order to improve the dispersibility with the matrix resin, surface treatment may be performed with a silane coupling agent or the like.

  Organic fine particles include silicone resin fine particles (including cured organopolysiloxanes (crosslinked products) such as silicone rubber and silicone gel), epoxy resin fine particles, urea resin fine particles, fluororesin fine particles, polycarbonate resin fine particles. The fine particles may be used alone or in combination of two or more. Silicone resin-based fine particles are preferable from the viewpoints of transparency and heat resistance. It is also possible to use core / shell type fine particles having different materials in the central portion and the surface layer portion.

  Among the plurality of fine particles having different refractive indexes, the concentration of the fine particles having the refractive index closest to the refractive index of the matrix resin in the solid content of the sealing composition is 1 to 30 vol%. By setting it in this concentration range, structural viscosity (thixotropic property) due to appropriate fine particles is expressed, and sedimentation of a phosphor having a high density can be suppressed. In addition, the fine particles having the refractive index closest to the refractive index of the matrix resin can reduce the re-absorption loss of the phosphor by suppressing light scattering caused by the refractive index difference in the sealing resin, thereby improving the luminance. be able to. If it is less than 1 vol%, the effect of suppressing the sedimentation of the phosphor cannot be obtained, and if it exceeds 30 vol%, problems such as thickening tend to occur. More preferably, the lower limit is 5 vol% or more, and the upper limit is 15 vol% or less.

  Moreover, the density | concentration which other microparticles | fine-particles occupies for the solid content in the composition for sealing is 0.001-0.045 vol%. If it is less than 0.001 vol%, the light scattering effect cannot be obtained, and if it exceeds 0.045 vol%, the light scattering effect is too strong, causing an absorption loss of the phosphor, and the luminance is lowered. More preferably, the lower limit is 0.010 or more, and the upper limit is 0.028 vol% or less.

  In addition, in this invention, solid content refers to all the components except a solvent.

  In the light emitting diode sealing composition of the present invention, the fine particles having a refractive index closest to the refractive index of the matrix resin may be fine particles (a) having a difference from the refractive index of the matrix resin of less than 0.05. preferable. If the difference between the refractive index of all the fine particles and the refractive index of the matrix resin is 0.05 or more, light scattering is strong and it may be difficult to increase the concentration of the fine particles. Therefore, the fine particles (a) are preferably fine particles made of the same material as the matrix resin. Since the matrix resin is preferably a silicone resin, at least one of the fine particles is preferably a silicone fine particle.

  The concentration of the fine particles (a) having a difference from the refractive index of the matrix resin of less than 0.05 in the solid content in the sealing composition is preferably 1 to 30 vol%. More preferably, the lower limit is 5 vol% or more, and the upper limit is 15 vol% or less.

  On the other hand, the composition for sealing a light emitting diode of the present invention preferably contains fine particles (b) having a difference from the refractive index of the matrix resin of 0.06 or more. If the difference between the refractive index of all the fine particles and the refractive index of the matrix resin is less than 0.06, light scattering is weak and it may be difficult to reduce the concentration of the fine particles. More preferably, it is 0.20 or more. Further, since the purpose is to cause light scattering, the upper limit of the refractive index with the matrix resin is not particularly limited, but is preferably 2.8 or less. Therefore, the fine particles (b) are preferably fine particles composed of a material having a refractive index different from that of the matrix resin. That is, it is preferable that at least one of the fine particles is an inorganic particle. For example, when a silicone resin is used as the matrix resin, the inorganic particles are preferably at least one selected from silica, alumina, zirconia, silicon nitride, and barium fluoride from the viewpoint of easy availability. It is particularly preferable to use inorganic particles such as alumina.

  The concentration of the fine particles (b) having a difference from the refractive index of the matrix resin of 0.06 or more in the solid content in the sealing composition is preferably 0.001 to 0.045 vol%. More preferably, the lower limit is 0.010 vol% or more, and the upper limit is 0.028 vol% or less.

  The fine particle concentration (vol%) was determined by observing the cross section of the cured product of the sealing composition with a scanning electron microscope (for example, a high resolution field emission scanning electron microscope “S4800” manufactured by Hitachi, Ltd.). It can be obtained from the ratio. For example, the concentration (vol%) can be calculated by measuring the area of fine particles in a 500 μm × 500 μm visual field, dividing it by the visual field area, and multiplying by 100. In the case of a phosphor sheet to be described later, it can be calculated by measuring the cured product in the same manner.

  The refractive index of the matrix resin and the fine particles is a refractive index with respect to sodium D line (589.3 nm) at 25 ° C. For the measurement of the refractive index, an Abbe refractometer, a Pulrich refractometer, an immersion refractometer, an immersion method, a minimum deflection angle method, or the like can be used.

The particle diameter of the fine particles is preferably in the range of 0.01 to 10 μm. The particle diameter is expressed by an average particle diameter, that is, a median diameter (D ₅₀ ), and is measured by a microtrack method (a method using a microtrack laser diffraction type particle size distribution analyzer manufactured by Nikkiso Co., Ltd.). That is, in a volume-based particle size distribution obtained by measurement by laser diffraction / scattering particle size distribution measurement, a particle system having a cumulative amount of passage from the small particle size side of 50% is obtained as the median diameter (D ₅₀ ). If it is smaller than 0.01 μm, it is difficult to obtain a sedimentation suppressing effect, and if it exceeds 10 μm, it is difficult to uniformly disperse it. More preferably, it is 0.1-1.0 micrometer.

  Hereinafter, the composition for sealing a light-emitting diode of the present invention will be described using a silicone resin as a matrix as an example. In addition, these productions may use other known methods, and are not limited to the methods described later.

  The silicone resin used as the matrix resin includes a silicone (A) having an alkenyl group bonded to a silicon atom, a silicone (B) having a hydrogen atom bonded to a silicon atom, and a platinum-based catalyst as a hydrosilylation reaction catalyst (C). Addition reaction curable silicones are preferred. For example, Toray Dow Corning Co., Ltd. sealing material “OE6630” can be used.

  A composition containing (A) and (B), a mixture containing (A) and (C), and a refractive index difference between the silicone fine particles (D) and the matrix resin as fine particles having a refractive index difference of less than 0.05 with the matrix resin. A predetermined amount of alumina fine particles (E) are mixed and dispersed as fine particles having a rate difference of 0.06 or more. For mixing and dispersion, the composition for encapsulating a light emitting diode of the present invention is obtained by homogeneously mixing and dispersing with a stirrer / kneader such as a homogenizer, a self-revolving stirrer, three rollers, a ball mill, a planetary ball mill, or a bead mill. Can be produced. It is also preferable to degas by vacuum or reduced pressure after mixing or dispersing.

  The composition for sealing a light-emitting diode thus obtained is injection-molded, compression-molded, cast-molded, transfer-molded, coated, dispensed, printed, transferred, cured, and then cured to a desired shape. The phosphor dispersion can be placed on the LED chip. The curing conditions for heat curing are usually 40 to 250 ° C. for 1 minute to 5 hours, preferably 100 ° C. to 200 ° C. for 5 minutes to 2 hours. Thus, an LED package using the light emitting diode sealing composition of the present invention can be produced.

  In addition, the composition for sealing a light-emitting diode of the present invention can be installed not only directly on the LED chip but also on the LED chip after forming a sheet-like molded product. The sheet-like molded product includes a matrix resin, a phosphor, and a plurality of fine particles having different refractive indexes, and among the fine particles, a fine particle having a refractive index closest to the refractive index of the matrix resin is a solid in the phosphor sheet. The density | concentration which occupies for a minute is 1-30 vol%, and the density | concentration which the other microparticles | fine-particles occupies for the solid content in a fluorescent substance sheet is 0.001-0.045 vol%.

  The composition for encapsulating a light emitting diode of the present invention is applied on a flexible base material (base substrate) having peelability in advance, dried, cured, or semi-cured, and then peeled and transferred onto an LED chip. By performing additional heating and curing as necessary, a phosphor dispersion having a desired shape can be placed on the LED chip. As the base material (base substrate), a known metal, film, glass, ceramic, paper, or the like can be used without particular limitation. Specifically, in addition to polyethylene terephthalate (PET) film, polypropylene (PP) film, polyphenylene sulfide (PPS) film, polyimide film, aramid film, etc., coated paper, aluminum foil or plate, steel foil or Although a plate and glass can be used, PET film, PPS film, and PP film are preferable in terms of economy and handleability, and polyimide is used in terms of heat resistance when a high temperature is required for curing the silicone composition. Fill is preferred. Moreover, glass is preferably used from the viewpoint of ease of production of the phosphor sheet and ease of separation of the phosphor sheet.

  In the present invention, a laminate containing a substrate and a phosphor sheet, which is a sheet-like molded product formed by applying the light-emitting diode sealing composition of the present invention onto the substrate, is a phosphor sheet laminate. The body.

  The thickness (film thickness) of the sheet-like molded product is preferably 5 to 1000 μm, more preferably 5 to 500 μm, and further preferably 50 to 200 μm from the viewpoint of handleability. In addition, when the thickness varies, the amount of phosphor on the LED chip varies, and as a result, the emission spectrum also varies. Therefore, the thickness variation is preferably ± 5%, more preferably ± 3%. The film thickness of the sheet in the present invention is the film thickness (average film thickness) measured based on the method A of measuring thickness by mechanical scanning in JIS K7130 (1999) plastic-film and sheet-thickness measuring method. That means. More specifically, it is obtained by measuring the film thickness using a micrometer such as a commercially available contact-type thickness meter using the measurement conditions of the method A of measuring the thickness by mechanical scanning. The difference between the maximum value or the minimum value of the film thickness and the average film thickness is calculated, and this value is divided by the average film thickness, and the value expressed in 100 minutes is the film thickness variation B (%).

Film thickness variation B (%) = (maximum film thickness deviation value * −average film thickness) / average film thickness × 100
* For the maximum film thickness deviation value, the one with the larger difference from the average film thickness is selected from the maximum value or the minimum value.

  The phosphor sheet of the present invention controls the storage elastic modulus at room temperature (25 ° C.) and the storage elastic modulus at a high temperature (100 ° C.) of the matrix resin, and the storage elastic modulus of the phosphor sheet is reduced to 0.2 at 25 ° C. It is preferably 1 MPa or more and less than 0.1 MPa at 100 ° C., and more preferably 0.5 MPa or more at 25 ° C. and less than 0.05 MPa at 100 ° C.

  The storage elastic modulus mentioned here is a storage elastic modulus when dynamic viscoelasticity measurement is performed. Dynamic viscoelasticity means that when shear strain is applied to a material at a sinusoidal frequency, the shear stress that appears when a steady state is reached is divided into a component (elastic component) whose strain and phase match, and the strain and phase are This is a technique for analyzing the dynamic mechanical properties of a material by decomposing it into components (viscous components) delayed by 90 °. Here, what is obtained by dividing the stress component whose phase matches the shear strain by the shear strain is the storage elastic modulus G ′, which represents the deformation and tracking of the material against the dynamic strain at each temperature. It is closely related to processability and adhesion.

  In the case of the phosphor sheet in the present invention, having a storage modulus of 0.1 MPa or more at 25 ° C. improves the handling properties without sticking of the phosphor sheet surface at room temperature (25 ° C.). In addition, since the sheet is perforated and cut without surrounding deformation even when the shearing stress is generated by punching by a die or cutting by a blade, workability with high dimensional accuracy can be obtained. Although the upper limit of the storage elastic modulus at room temperature is not particularly limited for the purpose of the present invention, it is preferably 1 GPa or less in view of the necessity to propose stress strain after being bonded to the LED chip. In addition, since the storage elastic modulus is less than 0.1 MPa at 100 ° C., if it is heated and pasted at 60 ° C. to 250 ° C., it quickly deforms and follows the shape of the LED chip surface, and has high adhesive strength. It is obtained. If the phosphor sheet is capable of obtaining a storage modulus of less than 0.1 MPa at 100 ° C., the storage modulus decreases as the temperature is increased from room temperature. However, in order to obtain practical adhesion, 60 ° C. or higher is preferable. In addition, when such a phosphor sheet is heated to a temperature exceeding 100 ° C., the storage elastic modulus further decreases and the sticking property is improved. However, at a temperature exceeding 250 ° C., the resin usually has thermal expansion and thermal contraction. And thermal decomposition problems are likely to occur. Therefore, a suitable heat bonding temperature is 60 ° C to 250 ° C. The lower limit of the storage elastic modulus at 100 ° C. is not particularly limited for the purpose of the present invention, but if the fluidity is too high at the time of heating and pasting on the LED element, the shape processed by cutting or punching before pasting Therefore, it is desirable that the pressure be 0.001 MPa or more.

  As long as the above storage elastic modulus can be obtained as a phosphor sheet, the resin contained therein may be in an uncured or semi-cured state. Then, it is preferable that resin contained is a thing after hardening. If the resin is in an uncured or semi-cured state, the curing reaction proceeds at room temperature during storage of the phosphor sheet, and the storage elastic modulus may be out of the proper range. In order to prevent this, it is desirable that the resin is completely cured, or has been cured to such an extent that the storage elastic modulus does not change for a long period of about one month when stored at room temperature.

  The phosphor-dispersed silicone composition can be applied to the base material (base substrate) by a reverse roll coater, blade coater, kiss coater, slit die coater, screen printing, etc. In order to obtain uniformity in the thickness of the sheet-like molded product of the dispersed silicone composition, it is preferably applied by a slit die coater.

  The obtained sheet-like molded product is cut into the same size as the LED chip, and placed on the LED chip by a device such as a mounter. Then, it seals with the transparent silicone resin which does not contain a fluorescent substance. Below, the application example to an LED chip is demonstrated in detail.

  The phosphor sheet laminate of the present invention can be applied to an optical semiconductor element having a general structure such as lateral, vertical, and Philip chip to form a laminate in which a phosphor layer is laminated on the surface of an LED chip. The phosphor sheet laminate of the present invention can be suitably used particularly for vertical and flip chip type LED chips having a large light emitting area. By directly covering the LED chip with the phosphor layer, light from the LED chip can be directly incident on the phosphor layer, which is the wavelength conversion layer, without being lost due to reflection or the like. It is preferable because uniform white light can be obtained efficiently. The wavelength conversion layer here refers to a layer that absorbs light emitted from the LED chip, converts the wavelength, and emits light having a wavelength different from that of the LED chip. The laminate obtained by the above method is packaged by performing metal wiring and sealing, and then incorporated into a module, so that it is suitable for various LED light emitting devices such as various illuminations, liquid crystal backlights, and headlamps. Can be used.

  The manufacturing method of the LED package using the phosphor sheet laminate of the present invention includes (A) an alignment step in which one section of the phosphor sheet is opposed to a light emitting surface of one LED chip, and (B) It is a manufacturing method of an LED package including at least a bonding step of bonding the one section of the sheet and the light emitting surface of the one LED chip by pressing with a pressure tool. Further, the step (A) is an alignment step in which the surface of the phosphor sheet having the higher concentration of inorganic particles among the upper and lower surfaces of one section of the phosphor sheet is opposed to the light emitting surface of the one LED chip. It is preferable that it is a manufacturing method of an LED package.

  It is preferable to use a phosphor sheet using a heat fusion resin as a matrix resin because it can be easily adhered to the LED chip without an adhesive.

  When the phosphor sheet is attached to the LED chip, it is heated and attached. The heating temperature is preferably 60 ° C. or higher and 250 ° C. or lower, and more preferably 60 ° C. or higher and 150 ° C. or lower. By setting the temperature to 60 ° C. or higher, the resin design for increasing the difference in elastic modulus between the room temperature and the attaching temperature becomes easy. Moreover, since the thermal expansion and thermal shrinkage of the base material and the phosphor sheet can be reduced by setting the temperature to 250 ° C. or lower, the accuracy of pasting can be increased. In particular, when the phosphor sheet is pre-perforated and aligned with a predetermined portion on the semiconductor element, the position accuracy of pasting is important. In order to increase the accuracy of pasting, it is more preferable to paste at 150 ° C. or lower. Furthermore, in order to improve the reliability of the LED package according to the present invention, it is preferable that there is no stress strain between the phosphor sheet and the LED chip. For this reason, the pasting temperature is preferably around the operating temperature of the LED light emitting device using the LED package of the present invention, preferably within ± 20 ° C. of the operating temperature. The LED light emitting device rises in temperature from 80 ° C. to 130 ° C. when lit. Therefore, the pasting temperature is desirably 60 ° C. or higher and 150 ° C. or lower in order to bring the operating temperature and the pasting temperature closer. Therefore, the characteristics of the phosphor sheet designed to sufficiently reduce the storage elastic modulus at 100 ° C. are important.

  As a method for attaching the phosphor sheet, any existing apparatus can be used as long as it can be heated and pressurized at a desired temperature. As will be described later, after the phosphor sheet is cut into individual pieces and then attached to individual LED chips, the wafer is diced and phosphor sheets after being collectively attached to the wafer on which the LED chips before dicing are made. However, in the case of attaching the phosphor sheet after dividing it into individual pieces, a flip chip bonder can be used. When affixing to wafer level LED chips in a lump, it is affixed with a thermocompression bonding tool having a heating portion of about 100 mm square. In either case, after the phosphor sheet is thermally fused to the LED chip at a high temperature, the phosphor sheet is allowed to cool to room temperature and the substrate is peeled off. By providing the relationship between the temperature and the elastic modulus as in the present invention, the phosphor sheet after being allowed to cool to room temperature after heat fusion can be easily peeled off from the substrate while firmly adhering to the LED chip. It becomes possible.

  A method for cutting the phosphor sheet will be described. The phosphor sheet is pre-cut into individual pieces before being attached to the LED chip, and then attached to individual LED chips, and the phosphor sheet is attached to the wafer level LED chip and then simultaneously with wafer dicing. Then, there is a method of cutting the phosphor sheet. In the case of cutting in advance before sticking, the uniformly formed phosphor sheet is processed into a predetermined shape by laser processing or cutting with a blade and divided. Since processing with a laser gives high energy, it is very difficult to avoid scorching of the resin and deterioration of the phosphor, and cutting with a blade is desirable. In order to improve workability when cutting with a blade, it is very important that the storage elastic modulus of the phosphor sheet at 25 ° C. is 0.1 MPa or more. As a cutting method with a blade, there are a method of pushing and cutting a simple blade and a method of cutting with a rotary blade, both of which can be suitably used. As an apparatus for cutting with a rotary blade, an apparatus used for cutting (dicing) a semiconductor substrate called a dicer into individual chips can be suitably used. If the dicer is used, the width of the dividing line can be precisely controlled by the thickness of the rotary blade and the condition setting, so that higher processing accuracy can be obtained than when cutting with a simple cutting tool.

  When the phosphor sheet in a state of being laminated with the base material is cut, the whole base material may be singulated, or the phosphor sheet may be singulated and the base material may not be cut. Alternatively, the substrate may be a so-called half cut in which a cut line that does not penetrate is entered. The phosphor sheet thus separated is heat-fused onto individual LED chips.

  In addition, when the phosphor sheets are separated into pieces while the base material is continuous, they may be heat-sealed to the wafer level LED chips before dicing as they are.

  When the phosphor sheet is thermally bonded to the wafer level LED chips before dicing, the phosphor sheet can be cut together with the dicing of the LED chip wafer after being attached. The dicing of the wafer is performed by the above-mentioned dicer, and the conditions such as the number of rotations and the cutting speed when cutting are optimized for the conditions for cutting the semiconductor wafer. Therefore, the conditions are optimal for cutting the phosphor sheet. Although it is difficult to do, it can cut suitably by using a phosphor sheet having a high elastic modulus at 25 ° C. as in the present invention.

  In any of the above steps, when the phosphor sheet is attached to the LED chip having the electrode on the upper surface, the portion is previously removed before attaching the phosphor sheet in order to remove the phosphor sheet of the electrode portion. It is desirable to make a hole in the hole. Although known methods such as laser processing and die punching can be suitably used for drilling, laser processing causes burning of the resin and deterioration of the phosphor, so punching with a die is more desirable. When punching is performed, punching cannot be performed after the phosphor sheet is attached to the LED chip. Therefore, it is essential to perform punching before attaching the phosphor sheet. In the punching process using a mold, a hole having an arbitrary shape or size can be formed depending on the electrode shape of the LED chip to be attached. Any size and shape of the hole can be formed by designing the mold, but the electrode joint portion on the LED chip inside and outside the 1 mm square is preferably 500 μm or less in order not to reduce the area of the light emitting surface. The hole is formed with a size of 500 μm or less in accordance with its size. In addition, an electrode for performing wire bonding or the like needs to have a certain size and is at least about 50 μm. Therefore, the hole is about 50 μm in accordance with the size. If the size of the hole is too larger than the electrode, the light emitting surface is exposed, light leakage occurs, and the color characteristics of the LED package deteriorate. On the other hand, if it is too small than the electrode, the wire touches at the time of wire bonding, resulting in poor bonding. Therefore, in the drilling process, it is necessary to process small holes of 50 μm or more and 500 μm or less with high accuracy within ± 10%. In order to improve punching accuracy, the storage elastic modulus of the phosphor sheet at 25 ° C. Is very important to be 0.1 MPa or more.

  When the phosphor sheet that has been cut and perforated is aligned and adhered to a predetermined portion of the LED chip, an affixing device having an optical alignment (alignment) mechanism is required. At this time, it is difficult to align the phosphor sheet and the LED chip in terms of work, and in practice, the alignment is often performed in a state where the phosphor sheet and the LED chip are lightly contacted. At this time, if the phosphor sheet has adhesiveness, it is very difficult to move it in contact with the LED chip. If the phosphor sheet laminate of the present invention is aligned at room temperature, it is not sticky, so that it is easy to align the phosphor sheet and the LED chip with light contact.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to this. The raw materials used in the compositions in the examples and comparative examples, and the evaluation methods in the examples and comparative examples are as follows.

[Light emitting diode sealing composition]
Sealing material 1 (matrix resin): “OE6630” (silicone resin, refractive index: 1.53, density: 1.17 g / cm ³ ) manufactured by Toray Dow Corning. Since it is a two-component mixed type, it consists of component A and component B.

Sealing material 2 (matrix resin): “OE6336” manufactured by Toray Dow Corning (silicone resin, refractive index: 1.41, density: 1.03 g / cm ³ ). Since it is a two-component mixed type, it consists of component A and component B.

Fine particles 1: Silicon fine particles (refractive index: 1.56, particle size: 0.5 μm, density: 1.17 g / cm ³ ). The fine particles 1 were produced by the following method. Attach stirrer, thermometer, reflux tube and dropping funnel to 2L four-necked round bottom flask, and put 2L of 2.5% ammonia water containing 1ppm of polyether-modified siloxane "BYK333" as surfactant into the flask at 300rpm. The temperature was raised in an oil bath while stirring. When the internal temperature reached 50 ° C., 200 g of a mixture of methyltrimethoxysilane and phenyltrimethoxysilane (71/29 mol%) was dropped from the dropping funnel over 30 minutes. Stirring was continued for 60 minutes at the same temperature, and then about 5 g of acetic acid (special grade reagent) was added, stirred and mixed, and then filtered. 600 mL of water was added twice to the generated particles on the filter and 200 mL of methanol was added once, followed by filtration and washing. The cake on the filter was taken out, crushed, and freeze-dried for 10 hours to obtain 60 g of white powder. The obtained particles were monodispersed spherical fine particles having an average particle diameter, that is, a median diameter (D ₅₀ ) of 0.5 μm. As a result of measuring the refractive index of the fine particles by the immersion method, a value of 1.56 was obtained. As a result of observing this particle cross section with TEM, it was confirmed that the inside of the particle was a particle having a single structure.

Fine particles 2: High-purity alumina “AKP3000” manufactured by Sumitomo Chemical Co., Ltd. (refractive index: 1.76, particle size: 0.5 μm, density: 3.95 g / cm ³ ).

Fine particles 3: High-purity alumina “AKP50” manufactured by Sumitomo Chemical Co., Ltd. (refractive index: 1.76, particle size: 0.2 μm, density: 3.95 g / cm ³ ).

Fine particles 4: Zirconia powder “KZ-0Y-LSF” manufactured by Kyoritsu Material Co., Ltd. (refractive index: 2.20, particle size: 0.2 μm, density: 5.90 g / cm ³ ).

Fine particles 5: silica powder “SO-E1” manufactured by Admatechs Co., Ltd. (refractive index: 1.46, particle size: 0.7 μm, density: 2.2 g / cm ³ )
Fine particles 6: Silicone fine particles (refractive index: 1.42, particle size: 0.5 μm, density: 1.02 g / cm ³ ). The fine particles 6 were produced in the same manner except that 200 g of methylmethoxysilane was used instead of 200 g of the mixture (71/29 mol%) of methyltrimethoxysilane and phenyltrimethoxysilane in the production method of the fine particles 1. The obtained particles were monodispersed spherical fine particles having an average particle diameter, that is, a median diameter (D ₅₀ ) of 0.5 μm. As a result of measuring the refractive index of the fine particles by the immersion method, a value of 1.42 was obtained. As a result of observing this particle cross section with TEM, it was confirmed that the inside of the particle was a particle having a single structure.

Phosphor 1: “NYAG-02” manufactured by Intematix (Ce-doped YAG phosphor, median diameter (D ₅₀ ): 7 μm, density: 4.8 g / cm ³ ).

Phosphor 2: “EY4453” manufactured by Intematix (silicate phosphor, median diameter (D ₅₀ ): 15.5 μm, density: 4.48 g / cm ³ ).

[Evaluation methods in Examples and Comparative Examples]
<Preparation of illuminance evaluation sample>
The illuminance evaluation samples in Examples 1 to 5 and Comparative Examples 1 to 5 were prepared as follows. A predetermined amount of sealing material (matrix resin), fine particles, and phosphors are weighed in a polyethylene container having a volume of 300 mL so as to have the concentrations shown in Tables 1 and 2, and a planetary stirring deaerator “Mazerustar KK” manufactured by Kurabo Industries Co., Ltd. -400 ", the mixture was stirred and degassed at 1,000 rpm for 10 minutes. The obtained composition was poured into a 1 mm thick, 3 cm × 3 cm mold and molded by hot pressing at a temperature of 150 ° C. for 20 minutes. Then, it dried for 2 hours at 150 degreeC in perfect oven, and produced the sheet-like sample.

<Illuminance measurement>
The illuminance in Examples 1 to 5 and Comparative Examples 1 to 5 was evaluated in the following manner. As shown in FIG. 1, on a LED light source 1 ("MS-LED-460" manufactured by Prizmatix, wavelength: 460 nm, output:> 50 mW), a diffusion sheet 2 (Co., Ltd.) cut so as to cover the LED light source 1 ) "LSD-60x1PC10-F12" manufactured by Optical Solutions Co., Ltd.), black metal shading plate 3 with a 1 mm diameter hole, sheet-like sample 4, black metal shading cylinder 5, illuminance meter 6 (manufactured by Konica Minolta) The light receiving portions of the color illuminometer “CL-200A”) were placed in order, and the illuminance (lx) of the sheet-like sample 4 was measured. If the measurement is always performed at a constant distance and a constant angle, the illuminance is proportional to the luminance, so that the illuminance can be used as an index of luminance. The increase rate of illuminance with respect to Comparative Example 1 is calculated by the following formula, and if the increase rate is positive, there is a brightness improvement effect (indicated as G in Tables 1 and 2, particularly the effect of increasing the increase rate by 2% or more is remarkable) If it is negative, it indicates that there is no luminance improvement effect (denoted as NG in Tables 1 and 2).

  Illuminance increase rate (%) = {(illuminance of each example, comparative example) − (illuminance of comparative example 1)} / (illuminance of comparative example 1) × 100.

<Examples 1 to 3 and Comparative Examples 1 to 3 (brightness enhancement effect by concentration of fine particles 2)>
Preparation of an illuminance evaluation sample, illuminance measurement, and evaluation of an increase rate of illuminance were performed as described above, and the results are shown in Table 1 and FIG. In Examples 1 to 3, the brightness improvement effect was obtained as compared with Comparative Example 1. In particular, the effect was great in Examples 2 and 3. In Comparative Examples 2 and 3, the luminance decreased on the contrary.

<Examples 4 to 5 and Comparative Examples 1 and 4 to 5 (brightness enhancement effect due to the concentration of the fine particles 3)>
As described above, the illuminance evaluation sample was prepared, the illuminance measurement, and the increase rate of the illuminance were evaluated, and the results are shown in Table 2 and FIG. In Examples 4 to 5, a brightness improvement effect was obtained as compared with Comparative Example 1. In Examples 4 and 5, the effect was great. In Comparative Examples 4 and 5, the luminance decreased on the contrary.

<Examples 6 to 9, Comparative Examples 1, 6, and 7 (brightness improvement effect by concentration of fine particles 4)>
The illuminance evaluation sample was prepared as described above, the illuminance measurement, and the illuminance increase rate were evaluated, and the results are shown in Table 3 and FIG. In Examples 6 to 9, a brightness improvement effect was obtained as compared with Comparative Example 1. In Comparative Examples 6 and 7, the luminance decreased on the contrary.

<Examples 10 to 13, Comparative Examples 1, 8, and 9 (brightness enhancement effect due to concentration of fine particles 5)>
The illuminance evaluation sample was prepared as described above, the illuminance measurement, and the illuminance increase rate were evaluated, and the results are shown in Table 4 and FIG. In Examples 10 to 13, a brightness improvement effect was obtained as compared with Comparative Example 1. In Comparative Examples 8 and 9, the luminance decreased on the contrary.

<Examples 14 to 17, Comparative Examples 1, 10, and 11 (Brightness improvement effect of fine particles 5 in the sealing material 2)>
As described above, the illuminance evaluation sample was prepared, the illuminance measurement and the illuminance increase rate were evaluated, and the results are shown in Table 5 and FIG. In Examples 14 to 17, a brightness improvement effect was obtained as compared with Comparative Example 1. In Comparative Examples 10 and 11, the luminance decreased on the contrary.

<Production of LED package and brightness evaluation>
The LED packages in Examples 18 to 23 and Comparative Examples 12 to 14 were produced as follows. First, a predetermined amount of sealing material (matrix resin), fine particles, and phosphors are weighed in a polyethylene container having a volume of 300 mL so as to have the concentration shown in Table 6, and a planetary stirring deaerator “Mazerustar KK” manufactured by Kurabo Industries. -400 ", the mixture was stirred and degassed at 1,000 rpm for 10 minutes. The obtained composition was placed on a frame (Enomoto's frame “TOP LED BASE”) on which an LED chip (“GM2QT450G” manufactured by Showa Denko KK, average wavelength: 453.4 nm) was mounted. LED package was produced by pouring using “MPP-1”) and curing at 80 ° C. for 1 hour and 150 ° C. for 2 hours. The manufactured LED package was turned on by passing a current of 20 mA, and using an instantaneous multi-photometry system (“MCPD-7700” manufactured by Otsuka Electronics Co., Ltd.), the luminance immediately after the start of the test was measured. It was. The luminance increase rate relative to Comparative Example 12 is calculated by the following formula, and if the increase rate is positive, there is a luminance improvement effect (indicated as G in Table 6, especially the effect that the increase rate is 2% or more is remarkable) Is expressed as E), and if it is negative, there is no luminance improvement effect (denoted as NG in Table 6).

  Brightness increase rate (%) = {(luminance of each example, comparative example) − (luminance of comparative example 12)} / (luminance of comparative example 12) × 100.

<Examples 18 to 23, Comparative Examples 12 to 14 (brightness enhancement effect due to the concentration of the fine particles 2)>
As described above, the LED package was prepared, the luminance was measured, and the luminance increase rate was evaluated. The results are shown in Table 6 and FIG. In Examples 18 to 23, a brightness improvement effect was obtained as compared with Comparative Example 12. Especially in Examples 19 to 21, the effect was great. In Comparative Examples 13 and 14, the luminance decreased on the contrary.

<Production and brightness evaluation of LED package using phosphor sheet laminate>
The sealing composition used in Examples 6 to 11 was applied onto PET as a substrate using a slit die coater, heated and dried at 120 ° C. for 1 hour, and 80 μm, 100 mm square phosphor sheet laminate. Got. The phosphor sheet laminate on the base material was cut into 1 mm square × 10000 pieces, and at the same time, grooves were cut into portions corresponding to the cut portions of the base material. For cutting, a cutting device, GCUT manufactured by UHT, was used. The cut phosphor sheet laminate is aligned with a substrate on which a 1 mm square flip chip type blue LED chip is mounted so as to face the light emitting surface of the LED chip, and die bond paste “EN-4900GC” (Made by Hitachi Chemical Co., Ltd.) was attached to the light emitting surface of the LED chip with a pressure tool. The die bond paste was cured by heating on a hot plate at 100 ° C. for 1 minute to obtain an LED package. The manufactured LED package was turned on by passing a current of 20 mA, and using an instantaneous multi-photometry system (“MCPD-7700” manufactured by Otsuka Electronics Co., Ltd.), the luminance immediately after the start of the test was measured. It was. The luminance increase rate relative to Comparative Example 15 is calculated according to the following formula. Is expressed as E), and if it is negative, there is no luminance improvement effect (denoted as NG in Table 7).

  Brightness increase rate (%) = {(luminance of each example, comparative example) − (luminance of comparative example 15)} / (luminance of comparative example 15) × 100.

<Examples 24 to 29, Comparative Examples 15 to 17 (brightness enhancement effect due to the concentration of the fine particles 2)>
As described above, the LED package using the phosphor sheet laminate was prepared, the luminance was measured, and the luminance increase rate was evaluated. The results are shown in Table 7 and FIG. In Examples 24-29, the brightness improvement effect was obtained as compared with Comparative Example 15. In particular, the effects were great in Examples 24 and 25. In Comparative Examples 16 and 17, the luminance decreased on the contrary.

DESCRIPTION OF SYMBOLS 1 LED light source 2 Diffusion sheet 3 Light-shielding plate 4 Sheet-like sample 5 Light-shielding cylinder 6 Illuminance meter 7 Stand

Claims (15)

A composition for sealing a light-emitting diode comprising a matrix resin, a phosphor, and a plurality of fine particles having different refractive indexes, wherein the fine particles having a refractive index closest to the refractive index of the matrix resin among the fine particles are for sealing The concentration of the solid content in the composition is 1 to 30 vol%, and the concentration of the other fine particles in the solid content of the sealing composition is 0.001 to 0.045 vol%. Composition. The fine particles having the refractive index closest to the refractive index of the matrix resin are fine particles (a) having a difference from the refractive index of the matrix resin of less than 0.05, and the fine particles (a) are contained in the sealing composition. The composition for encapsulating a light emitting diode according to claim 1, wherein the concentration in the solid content is 1 to 30 vol%. A plurality of fine particles having different refractive indices include at least a fine particle (b) having a difference from the refractive index of the matrix resin of 0.06 or more, and the concentration of the fine particles (b) in the solid content in the sealing composition The composition for sealing a light-emitting diode according to claim 1, wherein the content is 0.001 to 0.045 vol%. The composition for sealing a light-emitting diode according to any one of claims 1 to 3, wherein the matrix resin is a silicone resin. The composition for sealing a light-emitting diode according to any one of claims 1 to 4, wherein at least one of the fine particles is a silicone fine particle. The composition for encapsulating a light emitting diode according to any one of claims 1 to 5, wherein at least one of the fine particles is an inorganic particle. The composition for sealing a light-emitting diode according to claim 6, wherein the inorganic particles are at least one selected from silica, alumina, zirconia, and silicon nitride. The LED package using the composition for light emitting diode sealing in any one of Claims 1-7. A phosphor sheet comprising a matrix resin, a phosphor, and a plurality of fine particles having different refractive indexes, wherein the fine particles having a refractive index closest to the refractive index of the matrix resin among the fine particles are solid content in the phosphor sheet. The phosphor sheet whose density | concentration is 1-30 vol%, and the density | concentration which the other microparticles | fine-particles occupies for the solid content in a phosphor sheet is 0.001-0.045 vol%. The phosphor sheet according to claim 9, wherein the base material is glass. The phosphor sheet according to claim 9, wherein the substrate is a polyethylene terephthalate (PET) film, a polyphenylene sulfide (PPS) film, or a polypropylene (PP) film. The phosphor sheet according to any one of claims 9 to 11, having a thickness of 5 to 1000 µm. The phosphor sheet according to any one of claims 9 to 12, wherein the phosphor sheet has a storage elastic modulus at 25 ° C of 0.1 MPa or more and a storage elastic modulus at 100 ° C of less than 0.1 MPa. The LED package using the fluorescent substance sheet in any one of Claims 9-13. It is a manufacturing method of the LED package using the fluorescent substance sheet in any one of Claims 9-14, Comprising: (A) The position which makes one division of the said fluorescent substance sheet oppose the light emission surface of one LED chip A method for manufacturing an LED package, comprising at least a bonding step, and (B) a bonding step in which the one section of the sheet and the light emitting surface of the one LED chip are bonded by pressing with a pressing tool.

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