JP6739527B2 - Light emitting device - Google Patents

Description

The present invention relates to a light emitting device.

There is known a light emitting device (LED package) in which an LED (light emitting diode) element is mounted on a substrate and the LED element is sealed with a translucent resin containing a phosphor. In such a light emitting device, white light or the like can be obtained depending on the application by mixing the light from the LED element and the light obtained by exciting the phosphor with the light from the LED element.

Patent Document 1 describes a light emitting device including a light emitting element, a package having a recess for arranging the light emitting element, and a resin containing a phosphor and a filler. In this light emitting device, the relative magnitude of specific gravity is (phosphor)>(filler)>(resin), and the filler deposition layer is arranged on the phosphor deposition layer covering the bottom surface side of the recess and the top surface of the light emitting element, The phosphor deposition layer disposed on the bottom surface side of the recess is lower than the height of the light emitting layer of the light emitting element, and the filler deposition layer disposed on the phosphor deposition layer disposed on the bottom surface side of the recess is the side surface of the emission layer. Is covered.

Patent Document 2 discloses a light emitting device including a base, a light emitting element mounted on the upper surface of the base via a mount portion, and a sealing resin for sealing the light emitting element, wherein the sealing resin is the mount portion. A phosphor-containing first layer covering the light emitting element above, a phosphor-containing second layer formed on the upper surface of the base body around the mount portion, and a filler formed on the phosphor-containing second layer around the mount portion A light emitting device having a containing layer is described.

Further, Patent Document 3 discloses a light conversion member made of glass containing phosphor particles dispersed therein, wherein a nanofiller having a 50% particle diameter of 50 nm or less is adsorbed on the surface of the phosphor particles. There is described a light conversion member further containing a heat resistant filler having a 50% particle diameter D50 of 5 to 30 μm dispersed therein.

JP, 2016-026404, A International Publication No. 2012/029695 Japanese Unexamined Patent Publication No. 2015-046579

The phosphor in the encapsulation resin generates heat by being excited by the light from the LED element. Therefore, when the phosphor is dispersed in the encapsulation resin, the temperature of the encapsulation resin rises during light emission and This leads to a decrease in life and luminous efficiency of the LED element. For this reason, the phosphor is allowed to spontaneously settle in the encapsulating resin during manufacturing, and then the encapsulating resin is cured, so that the phosphor is placed closer to the mounting board of the LED element and the heat from the phosphor is mounted. It is desirable to facilitate release to the substrate side. However, when the phosphor is completely settled in the sealing resin, the phosphor is deposited on the upper surface of the mounting substrate and the upper surface of the LED element, but the phosphor layer is formed on the side surface and the corner (obliquely above) of the LED element. Are hard to form. In this case, the wavelength conversion by the phosphor with respect to the light emitted obliquely upward of the LED element becomes insufficient, so that the color corresponding to the emission wavelength of the LED element becomes strong in that direction, and color unevenness occurs on the light emitting surface of the light emitting device. Occurs (that is, chromaticity of emitted light has angular directivity).

In order to prevent both overheating of the sealing resin and color unevenness of the light emitting surface, it is desirable to be able to realize a "semi-sedimentation state" that is intermediate between the state in which the phosphors are dispersed and the state in which the phosphors are settled in the sealing resin. .. The sedimentation state of the phosphor can be obtained by, for example, leaving the sealing resin in an uncured state during the production of the light-emitting device, for example, by allowing it to stand for several hours. If so, it will be in a semi-settling state. However, if it is attempted to realize a semi-sedimentation state by shortening the sedimentation time, variation in each product becomes large, and stable production cannot be performed. Therefore, it is practically difficult to adopt such a method.

Therefore, the present invention can be manufactured without lowering the yield, the heat generated by the phosphor that converts the wavelength of the light from the LED element is easily emitted through the mounting substrate, and the angular directivity of the chromaticity of the emitted light occurs. An object of the present invention is to provide a difficult light emitting device.

A mounting substrate, an LED element mounted on the mounting substrate, a phosphor excited by the LED element, and a nanofiller having an average particle size in the range of 1 nm to 100 nm are contained, and a transparent member for sealing the LED element is included. An encapsulating resin having a light-emitting property, which is formed by sinking a phosphor so as to cover the upper surface and side surfaces of the LED element and diagonally above the LED element, and rises along the shape of the LED element. Provided is a light emitting device having a sedimented layer of phosphor.

In the above light emitting device, it is preferable that the sealing resin further contains a filler having an average particle diameter in the range of 1 μm to 100 μm.

In the above light emitting device, the sealing resin is arranged on the upper side of the sedimentation layer, and the dispersion layer containing the phosphor in a higher concentration as it goes downward and the dispersion layer is arranged on the upper side of the dispersion layer to disperse the phosphor from the dispersion layer. It is preferable to further have a resin layer containing a low concentration.

In the above light emitting device, it is preferable that the mounting substrate has a mount section that is one step higher in height than the peripheral section, and the LED element is mounted on the upper surface of the mount section.

The above light emitting device can be manufactured without lowering the yield, the heat generated by the phosphor that converts the wavelength of the light from the LED element is easily released through the mounting substrate, and the angular directivity of the chromaticity of the emitted light occurs. Hateful.

3A and 3B are a cross-sectional view and a top view of the light emitting device 1. (A) and (B) are cross-sectional photographs of the light emitting device 1 ′ and the light emitting device 1 of the comparative example. (A)-(D) is a schematic diagram for demonstrating the fluorescent substance layer of light-emitting device 1,1'. 7A and 7B are a cross-sectional view and a top view of the light emitting device 2. (A)-(D) is a schematic diagram for demonstrating the fluorescent substance layer of light-emitting devices 2 and 2'. (A)-(D) is a schematic diagram for demonstrating the fluorescent substance layer of light-emitting device 3,3'. (A) to (C) are enlarged photographs showing a part of the sealing resin 30 of the light emitting device 1.

Hereinafter, the light emitting device will be described with reference to the drawings. However, it should be understood that the invention is not limited to the drawings or the embodiments described below.

1A and 1B are a cross-sectional view and a top view of the light emitting device 1, respectively. The light emitting device 1 is a light emitting device (LED package) that includes an LED element as a light emitting element and emits white light and the like by utilizing wavelength conversion by a phosphor, and is used as, for example, an LED light source for various illuminations. The light emitting device 1 has a mounting substrate 10, an LED element 20, and a sealing resin 30 as main components. The number of LED elements 20 is not limited to one, and the light emitting device may be one in which a plurality of LED elements 20 are mounted on the mounting substrate 10.

The mounting substrate 10 has two connection electrodes (not shown) for connecting the LED element 20 to an external power source, and is a substrate on which the LED element 20 is mounted. For example, the mounting substrate 10 may be a ceramic substrate, a metal substrate such as aluminum or copper having excellent heat resistance and heat dissipation, and an insulating circuit in which the wiring pattern of the LED element 20 and the connection electrode are formed. It may be a laminate with a substrate. Alternatively, the mounting substrate 10 is a base of an LED package that has a recess in which the LED element 20 is mounted and is filled with the sealing resin 30, and has two lead electrodes for connecting the LED element 20 to an external power source. It may be.

The LED element 20 is an element composed of, for example, a gallium nitride-based compound semiconductor that emits light having a wavelength ranging from the ultraviolet region to the blue region. Hereinafter, the LED element 20 will be described as a blue LED element that emits blue light having an emission wavelength band of about 450 to 460 nm, but the LED element 20 may be an element that emits light of another wavelength. Good. The LED element 20 is mounted on the upper surface of the mounting board 10 by die bonding, and the positive and negative electrodes of the LED element 20 are electrically connected to the connection electrodes on the mounting board 10 by two bonding wires 21 (hereinafter, simply referred to as wires 21). Connected to each other. When the light emitting device has a plurality of LED elements 20, the LED elements 20 are also electrically connected by the wires 21. The mounting method of the LED element 20 is not limited to wire bonding and may be flip chip.

The sealing resin 30 is a translucent resin such as an epoxy resin or a silicone resin, and integrally seals the LED element 20 and the wire 21. Moreover, the sealing resin 30 contains a phosphor, a filler, and a nanofiller that are excited by the LED element 20. The light emitting device 1 may have a resin frame body that is a dam material that prevents the sealing resin 30 from flowing out. In that case, the inside region surrounded by the frame body is filled with the sealing resin 30. The LED element 20 and the wire 21 may be sealed by using.

The phosphor contained in the sealing resin 30 may be one kind or plural kinds. When the LED element 20 is a blue LED, the sealing resin 30 contains, for example, a yellow phosphor such as YAG (Yttrium Aluminum Garnet) and a red phosphor such as CaAlSiN ₃ :Eu ²⁺ . In this case, the light emitting device 1 emits white light obtained by mixing the blue light from the LED element 20 and the yellow light and the red light obtained by exciting the yellow phosphor and the red phosphor thereby. .. The average particle size of the phosphor particles contained in the sealing resin 30 is, for example, about several tens of μm.

The filler contained in the sealing resin 30 is a micron-sized particulate inorganic material having an average particle size in the range of 1 μm to 100 μm. As the filler, for example, silicon dioxide (silica), alumina, titania, zirconia, magnesia or the like may be used. The filler functions as a scattering material that diffuses light in the sealing resin 30 and causes the entire light emitting region of the light emitting device 1 configured by the LED element 20 and the sealing resin 30 to uniformly emit light.

The nanofiller contained in the sealing resin 30 is a nano-sized particulate inorganic material having an average particle size in the range of 1 nm to 100 nm. The filler and the nanofiller have different particle sizes by about three digits, but may be the same substance. As the nanofiller, for example, silicon dioxide (silica), alumina, titania, zirconia, magnesia or the like may be used. The nanofiller preferably has heat resistance and is easily adsorbed to the phosphor particles. As described later, the nanofiller suppresses the sedimentation of the phosphor particles and realizes a semi-sedimentation state of the phosphor particles.

When manufacturing the light emitting device 1, first, the LED element 20 is fixed to the upper surface of the mounting substrate 10 by die bonding, and the positive and negative electrodes of the LED element 20 are connected to the connection electrodes on the mounting substrate 10 by wire bonding. Then, the LED element 20 and the wire 21 are sealed by filling the periphery of the LED element 20 with the translucent sealing resin 30 containing the above-mentioned phosphor, filler and nanofiller. Then, while keeping the encapsulation resin 30 in an uncured state, the phosphors and fillers in the encapsulation resin 30 are allowed to spontaneously settle on the upper surfaces of the mounting substrate 10 and the LED elements 20 over several hours, and after several hours have elapsed. , The sealing resin 30 is cured by heating, for example. As a result, the light emitting device 1 shown in FIGS. 1A and 1B is completed.

FIG. 2A is a cross-sectional photograph of the light emitting device 1 ′ of the comparative example, and FIG. 2B is a cross-sectional photograph of the light emitting device 1. The light emitting device 1 ′ has the same configuration as the above light emitting device 1 except for the sealing resin. The sealing resin 30' of the light emitting device 1'is a silicone resin that contains a yellow phosphor, a red phosphor, and a filler of silicon dioxide, and does not contain a nanofiller. On the other hand, the sealing resin 30 of the light emitting device 1 is a silicone resin containing a yellow phosphor, a red phosphor, a silicon dioxide filler, and a nanofiller. The average particle size of the yellow phosphor, the red phosphor and the filler is about several μm to several tens of μm, and the average particle size of the nanofiller is about several nm to several tens nm. The nanofiller concentration in the sealing resin 30 is about 0.5 wt %.

3A to 3D are schematic diagrams for explaining the phosphor layers of the light emitting devices 1 and 1'. Specifically, FIG. 3A shows a cross section immediately after the LED element 20 is sealed with the sealing resin 30′ during manufacturing of the light emitting device 1′, and FIG. 3B shows the sealing resin 30. The cross section of the light emitting device 1', which is a completed product in which the phosphor in the' has settled, is shown. Similarly, FIG. 3C shows a cross section immediately after the LED element 20 is sealed with the sealing resin 30 during the manufacturing of the light emitting device 1, and FIG. 3D shows the fluorescence in the sealing resin 30. The cross section of the light-emitting device 1 which the body settled down and became a finished product is shown. The light emitting devices 1 and 1'are in the same state immediately after sealing, but the sedimentation states of the phosphors are different from each other.

As shown in FIGS. 2A and 3B, in the light emitting device 1 ′, the yellow phosphor, the red phosphor, and the filler particles in the sealing resin 30 ′ are the upper surface of the mounting substrate 10 and the LED element. It has settled on the upper surface of 20. More specifically, in the light emitting device 1 ′, a sedimentation layer 31 ′ of a yellow phosphor and a red phosphor is formed on the upper surface of the mounting substrate 10 and the upper surface of the LED element 20, and the phosphor particles are substantially formed thereon. The resin layer 33' is not contained in the above. The sedimentation layer 31' is divided into a layer mainly containing a yellow phosphor and a layer mainly containing a red phosphor. In the light emitting device 1 ′, the sedimentation layer of the phosphor is not formed at the corner portion (obliquely above) of the upper surface of the LED element 20 shown by the broken line 34 in FIG. 3B.

On the other hand, as shown in FIGS. 2B and 3D, in the light emitting device 1, the yellow phosphor and the red phosphor in the sealing resin 30 are in a uniformly dispersed state and a completely sedimented state. It is in a semi-settling state, which is in between. More specifically, the sealing resin 30 of the light emitting device 1 is arranged above the sedimentation layer 31 of the yellow phosphor, the red phosphor and the filler, and above the sedimentation layer 31. It has a dispersion layer 32 that is contained at a concentration, and a resin layer 33 that is disposed above the dispersion layer 32 and that does not substantially contain phosphor particles. Although some phosphor particles may exist in the resin layer 33, the concentration of the phosphor in the resin layer 33 is lower than the concentration of the phosphor in (the upper end of) the dispersion layer 32.

The boundary between the sedimentation layer 31 and the dispersion layer 32 and the boundary between the dispersion layer 32 and the resin layer 33 may not be clearly defined in practice, but are shown by broken lines for convenience in FIG. 3D. .. Further, unlike the illustrated example, the phosphor particles may exist up to the upper end of the sealing resin 30, and the sealing resin 30 may be composed of only the sedimentation layer 31 and the dispersion layer 32. The concentration of the phosphor at the upper end is preferably close to zero.

In the light emitting device 1, the fluorescent substance sinks so as to cover the upper surface and the side surfaces of the LED element 20 and the obliquely upper side of the LED element 20, and also at the corners of the upper surface of the LED element 20 indicated by the broken line 34 in FIG. A sedimentation layer 31 of phosphor is formed. As shown in FIG. 1(B), the sedimentation layer 31 spreads in the front, rear, left, and right directions of the LED element 20 in the same manner as shown in FIG. 3(D), and the four side surfaces and the upper surface of the LED element 20. , And diagonally above (on the four sides of the upper surface) isotropically covered. Unlike the sedimentation layer 31 ′ of the light emitting device 1 ′, the sedimentation layer 31 of the light emitting device 1 is a continuous layer that rises along the shape of the LED element 20.

When a silicone resin is used as the sealing resin 30 and silicon dioxide is used as the filler and the nanofiller, if the concentration of the nanofiller in the sealing resin 30 is about 0.4 to 0.5 wt %, the sealing resin When a sufficiently long time has passed while keeping 30 uncured, the semi-sedimentation state shown in FIG. 2(B) and FIG. 3(D) is obtained. In this semi-sedimentation state, some of the phosphor particles are still dispersed in the sealing resin, and the sedimentation state does not become complete even after a lapse of time.

On the other hand, even if the sealing resin 30 contains the nanofiller, if the concentration is 0.2 wt% or less, the same sedimentation state as the light emitting device 1′ shown in FIGS. 2A and 3B is obtained. become. Further, when the concentration of the nanofiller in the sealing resin 30 exceeds 0.5 wt %, the phosphor does not settle sufficiently even after a sufficiently long time, and the dispersion close to that shown in FIG. 3C is obtained. The state is maintained. The higher the concentration of the nanofiller in the sealing resin 30, the less likely the phosphor will settle.

If the phosphor remains dispersed in the sealing resin 30, as described above, the temperature of the sealing resin 30 may rise excessively during light emission. When a silicone resin is used as the sealing resin 30 and silicon dioxide is used as the filler and the nanofiller, the upper limit of the amount of the nanofiller that can be used is 0.5 wt% from the relationship with the heat resistant temperature of the sealing resin 30. It will be about. This upper limit is a value determined by the materials of the sealing resin and the nanofiller.

Even if a high-viscosity resin is used as the sealing resin 30 for the purpose of making it difficult for the phosphor to settle, the settling time only increases depending on the viscosity, and finally, as shown in FIG. The sedimentation state shown in FIG. In order to obtain the semi-sedimentation state shown in FIG. 2(B) and FIG. 3(D), the sealing resin 30 needs to contain a nanofiller having a nano-sized particle size.

When the sealing resin 30 containing a phosphor, a filler, and a nanofiller is used as in the light emitting device 1, the phosphor is settled to some extent, but it is not completely settled and the phosphor is also formed in the corner portion of the LED element 20. Layers can be formed. The fluorescent substance will completely settle if the sealing resin 30 contains the fluorescent substance and a micron-sized filler, but by adding a certain amount of nanofiller, the fluorescent substance can be precipitated "softly". become. If a certain amount of nanofiller is contained, the semi-sedimentation state shown in FIG. 2(B) and FIG. 3(D) will be obtained even if the type and concentration of the phosphor are changed or the type and concentration of the filler are changed. Maintained. Since the filler mainly functions as a scattering material as described above, the sealing resin 30 does not necessarily need to contain the filler in order to realize the semi-sedimentation state of the phosphor particles.

7(A) to 7(C) are enlarged photographs showing a part inside the sealing resin 30 of the light emitting device 1. The photographs in FIGS. 7A to 7C were taken at magnifications of 2,000 times, 3,000 times, and 20,000 times, respectively, and the length of the white line shown at the bottom of each photograph. Correspond to 10 μm, 1 μm, and 1 μm, respectively. 7B corresponds to a part of FIG. 7A and FIG. 7C corresponds to a part of FIG. 7B in an enlarged manner.

Reference numerals 51 to 53 in FIG. 7A denote particles of a red phosphor, a yellow phosphor, and a filler, respectively. In FIG. 7A, the micron-sized particles mixed in the sealing resin 30 are Can be seen. On the other hand, with regard to the nanofiller, the particle size is smaller than that of the phosphor or the filler by about three orders of magnitude, so the particles themselves cannot be seen in FIG. 7A, but many particles gather to form an aggregate. The striped pattern indicated by reference numeral 54 in 7(A) corresponds to the aggregate. As long as the concentration of the nanofiller is high to some extent, the agglomerate of the nanofiller causes a layered structure (mesh structure) that is intricately meshed in the sealing resin 30, as shown in an enlarged view in FIGS. 7(B) and 7(C). ) Is formed. Therefore, the phosphor particles having a low specific gravity are held in the sealing resin 30 due to the mesh structure thereof, and it is considered that the phosphor particles are unlikely to settle down even after a lapse of time.

In the light emitting device 1, the phosphor does not completely settle down and a phosphor layer having a constant thickness is formed including the corners of the LED element 20. Therefore, the light emitted obliquely upward of the LED element 20 is emitted in the other direction. The wavelength is converted by the phosphor in the sealing resin 30 in the same manner as the light emitted to the. Therefore, in the light emitting device 1, since angular directivity is less likely to occur in the chromaticity of emitted light, color unevenness on the light emitting surface is less likely to occur. Further, in the light emitting device 1, since the semi-sedimentation state is realized and the phosphor particles are arranged on the side close to the mounting substrate 10, the heat from the phosphor is easily released to the mounting substrate 10 side, and the sealing resin 30. Is less likely to overheat. Further, if the concentration of the nanofiller in the sealing resin 30 is the same, the same semi-sedimentation state is finally obtained. Therefore, in the light emitting device 1, the sealing resin is cured during the sedimentation without using the nanofiller. Compared with the case, variation in chromaticity for each product is reduced, and yield is improved.

4A and 4B are a cross-sectional view and a top view of the light emitting device 2, respectively. The light emitting device 2 has the same configuration as the above light emitting device 1 except for the mounting substrate. The mounting substrate 10 ′ of the light emitting device 2 has a mount portion 11 that is one step higher in height than the peripheral portion 12, and the LED element 20 is mounted on the upper surface of the mount portion 11. In other words, in the light emitting device 2, the peripheral portion 12 of the mount portion 11 on which the LED element 20 is mounted on the mounting substrate 10 ′ is a recess that is one step lower than the mount portion 11. The height of the mount portion 11 with respect to the peripheral portion 12 is preferably approximately the same as the height of the LED element 20. It should be noted that the mount portion 11 may be configured integrally with the mounting board 10 ′, or a component separate from the mounting board 10 ′ may be attached to the mounting board 10 ′. Also in the light emitting device 2, the number of the LED elements 20 is not limited to one, and may be plural.

5A to 5D are schematic diagrams for explaining the phosphor layers of the light emitting devices 2 and 2'. The light emitting device 2 ′ has the same configuration as the above light emitting device 2 except for the sealing resin. The sealing resin 40' of the light emitting device 2'includes a yellow phosphor, a red phosphor, and a filler, but does not contain a nanofiller, like the sealing resin 30' of the light emitting device 1'. On the other hand, the sealing resin 40 of the light emitting device 2 contains a yellow phosphor, a red phosphor, a filler and a nanofiller. FIG. 5(A) shows a cross section immediately after the LED element 20 is sealed with the sealing resin 40′ during manufacturing of the light emitting device 2′, and FIG. 5(B) shows the fluorescence in the sealing resin 40′. The cross section of the light-emitting device 2 ′ that is the finished product after the body sinks is shown. Similarly, FIG. 5C shows a cross section immediately after the LED element 20 is sealed with the sealing resin 40 during the manufacturing of the light emitting device 2, and FIG. 5D shows the fluorescence in the sealing resin 40. The cross section of the light-emitting device 2 which the body settled down and became a finished product is shown.

As shown in FIG. 5(B), in the light emitting device 2′, the sedimentation layers 41 of the yellow phosphor and the red phosphor are provided on the upper surface of the mount portion 11 and the peripheral portion 12 of the mounting substrate 10′ and on the upper surface of the LED element 20. 'Is formed. The sedimentation layer 41' is divided into a layer mainly containing a yellow phosphor and a layer mainly containing a red phosphor. A resin layer 43' that does not substantially contain phosphor particles is formed on the sedimentation layer 41'. In the light emitting device 2 ′, the sedimentation layer of the phosphor is not formed at the corner portion (obliquely above) of the upper surface of the LED element 20 shown by the broken line 44 in FIG. 5B.

On the other hand, as shown in FIG. 5D, the sealing resin 40 of the light emitting device 2 includes a sedimentation layer 41, a dispersion layer 42, and a resin layer similar to the sedimentation layer 31, the dispersion layer 32, and the resin layer 33 of the light emitting device 1. Has 43. Also in the light emitting device 2, the fluorescent substance is deposited so as to cover the upper surface and the side surfaces of the LED element 20 and the diagonally upper side of the LED element 20, and also at the corners of the upper surface of the LED element 20 indicated by the broken line 44 in FIG. , A phosphor sedimentation layer 41 is formed. The sedimentation layer 41 also isotropically covers the four side surfaces, the upper surface, and the diagonally upper sides (peripheries of the four sides of the upper surface) of the LED element 20.

In the light emitting device 2 as well, since the sealing resin 40 contains the nanofiller, the phosphor does not completely settle down and a phosphor layer having a constant thickness is formed including the corners of the LED element 20. Is less likely to have angular directivity, and color unevenness on the light emitting surface is less likely to occur. Further, also in the light emitting device 2, like the light emitting device 1, heat from the phosphor is easily released to the mounting substrate 10′ side, and the sealing resin is cured during the sedimentation without using the nanofiller so that the semi-sedimentation state is obtained. The product yield is also improved compared to the case where it is realized.

In the light emitting device 1, as shown in FIG. 3D, the side of the LED element 20 is buried in the sedimentation layer 31, so that the light emitted sideways from the LED element 20 is emitted upward. It will pass through the phosphor layer longer than. On the other hand, in the light emitting device 2, the peripheral portion 12 is located lower than the mount portion 11 on which the LED element 20 is mounted. Lower than 20. As a result, in the light emitting device 2, since the thickness of the sedimentation layer 41 on the side, obliquely above, and above the LED element 20 is substantially uniform, wavelength conversion is substantially uniformly performed regardless of the light emission direction. Therefore, the light emitting device 2 is less likely to cause color unevenness on the light emitting surface as compared with the light emitting device 1. Further, in the light emitting device 2, particularly when the light emitting device has a plurality of LED elements 20, a wasteful phosphor layer cannot be formed between the LED elements 20, so that the light extraction efficiency is higher than that of the light emitting device 1.

FIGS. 6A to 6D are schematic views for explaining the phosphor layers of the light emitting devices 3 and 3'. The light emitting devices 3 and 3′ have the same configuration as the above light emitting devices 1 and 1′, respectively, except that the sealing resins 70 and 70′ contain only one type of yellow phosphor. .. 6(A) to 6(D) are diagrams showing the same states as in FIGS. 3(A) to 3(D), respectively. The sealing resin 70 of the light emitting device 3 contains a yellow phosphor, a filler and a nanofiller, and the sealing resin 70' of the light emitting device 3'containing a yellow phosphor and a filler.

The settling layer 71 ′ and the resin layer 73 ′ in the sealing resin 70 ′ shown in FIG. 6B are shown in FIG. 3 (except that the settling layer 71 ′ is not divided into a plurality of layers for each type of phosphor. It is the same as the sedimentation layer 31′ and the resin layer 33′ of B). In the encapsulating resin 70′ without the nanofiller, the phosphor particles completely settle, and therefore settle at the corners of the upper surface of the LED element 20 (sides of the light emitting layer 22 of the LED element 20) shown by the broken line 74. There is no layer 71' and the light emitting layer 22 is exposed in the resin layer 73'.

The sedimentation layer 71, the dispersion layer 72, and the resin layer 73 in the sealing resin 70 shown in FIG. 6D are the same as the sedimentation layer 31, the dispersion layer 32, and the resin layer 33 in FIG. 3D. In the encapsulating resin 70 having the nanofiller, the sediment layer 71 of the phosphor particles is also formed at the corner portion of the upper surface of the LED element 20 shown by the broken line 74 to realize the semi-sedimentation state. In the sealing resin 70, the side of the light emitting layer 22 of the LED element 20 is covered with a sedimentation layer 71, and the semi-sedimentation state is a state in which the light emitting layer of the LED element is covered with a sedimentation layer of phosphor particles. It can be said that there is.

When the LED element 20 is a blue LED, the sealing resin of the light emitting device may contain only a yellow phosphor as a phosphor so that white light can be emitted in combination with blue light. In this case, a yellow phosphor having a particle size (median diameter D50) of 1 to 30 μm and a specific gravity of 2 to 10 g/cm ³ is used, and the concentration of the nanofiller with respect to the sealing resin 70 (silicone resin) is 0.2. It is preferable to set it within the range of 1.5 wt%. The yellow phosphor completely precipitates when the concentration of the nanofiller is 0.2 wt% or less, and remains dispersed in the sealing resin 70 when the concentration of the nanofiller exceeds 1.5 wt%. If the encapsulating resin 70 contains 0.2 to 1.5 wt% of nanofiller, a semi-sedimentation state is realized. Therefore, even in the light emitting device 3 shown in FIG. The sealing resin 70 is less likely to be overheated.

Claims (3)

Mounting board,
An LED element mounted on the mounting board;
A phosphor excited by the LED element and a nanofiller having an average particle diameter within a range of 1 nm to 100 nm, and a translucent sealing resin for sealing the LED element,
The sealing resin is
The phosphor is formed by being settled so as to cover the upper surface and the side surface of the LED element and diagonally above the LED element, and a settling layer of the phosphor that is raised so as to follow the shape of the LED element ,
A dispersion layer disposed on the upper side of the sedimentation layer and containing the phosphor in a higher concentration toward the lower side,
A resin layer disposed on the upper side of the dispersion layer and containing the phosphor at a lower concentration than the dispersion layer,
A light-emitting device having: The light emitting device according to claim 1, wherein the sealing resin further contains a filler having an average particle size within a range of 1 μm to 100 μm. The mounting board has a mount portion that is one step higher in height than the peripheral portion,
The LED element is mounted on the upper surface of the mounting portion, the light emitting device according to claim 1 or 2.