JP2007116112A - Light emitting device and its fabrication process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device employing phosphor particles having a large mean particle diameter (D50) effective for enhancing emission efficiency in which deterioration in fabricability or emission efficiency peculiar to the case employing phosphor particles having a large mean particle diameter (D50) is suppressed. <P>SOLUTION: The light emitting device comprises a substrate 5 having a recess, a light emitting element 2 arranged in the recess, and a phosphor layer 3 composed of phosphor particles having a mean particle diameter (D50) of 15-30 μm and transparent resin having viscosity of 1-3 Pa s before curing and filling the recess. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device such as an LED lamp and a manufacturing method thereof.

  LED lamps using light emitting diodes (LEDs) have been dramatically expanded in various fields such as backlights for liquid crystal displays, mobile phones, information terminals, and indoor / outdoor advertisements. In addition, LED lamps have long life and high reliability, and have features such as low power consumption, impact resistance, high-purity display color, and lightness and thinness. Application is also being attempted. When such an LED lamp is applied to various applications, it is important to obtain white light emission.

  As a typical method for realizing white light emission with an LED lamp, (1) a method using three LED chips that emit light in blue, green and red colors, and (2) a blue light emitting LED chip and yellow light or orange light. A method of combining yellow phosphor particles that emit light, and (3) a method of combining ultraviolet light emitting LED chips and three-color mixed phosphor particles of blue, green, and red (hereinafter referred to as RGB phosphors). One of them. Of these, the method (2) is generally widely used. Further, it has been reported that the luminous efficiency of 8.2 lm / W and the average color rendering index Ra86 to 90 were obtained by the method (3). Further, in the method (2), an increase in the average color rendering index Ra is expected by using red phosphor particles in addition to yellow phosphor particles.

  In the LED lamp to which the above-described methods (2) and (3) are applied, for example, an LED chip is provided in a recess of a frame, and a liquid transparent resin containing phosphor particles is injected into the recess and solidified. Thus, a structure in which a phosphor layer is formed is common (see, for example, Patent Document 1). In such LED lamps, improvement of light extraction efficiency based on the electrode shape of the LED chip such as a flip chip, and light distribution control by examining the chip shape are promoted, and the amount of light to the front surface of the chip increases. There is a tendency.

As the amount of light on the front surface of the chip increases, the average particle size of the phosphor particles to be added to and mixed with the liquid transparent resin has an influence on the light extraction efficiency. Generally, it is known that the larger the average particle diameter of the phosphor particles, the higher the light emission efficiency and the light extraction efficiency.
JP 2001-148516 A

  The phosphor layer of the LED lamp to which the above-described methods (2) and (3) are applied is generally a liquid transparent resin containing phosphor particles in a dispenser having a nozzle having a nozzle diameter of about 0.15 to 0.45 mm. It is formed by discharging a liquid transparent resin containing phosphor particles from the nozzle, and injecting and curing the resin in the recess.

  However, when a large phosphor particle having an average particle diameter (D50) of 15 μm or more is used, the phosphor particle settles in the dispenser and clogs and is not properly discharged, and the accuracy of injection into the recess is reduced. There is. On the other hand, even after being injected into the recess, the phosphor particles may settle and accumulate on the bottom before being cured, and the luminous efficiency may be lowered due to the increase in the density of the phosphor particles. For this reason, although the phosphor particles having a large average particle diameter (D50) are generally considered to be effective for improving the luminous efficiency, they are actually sufficient from the above-mentioned problems in production and luminous efficiency. It has not yet been used.

  The present invention uses phosphor particles having a large average particle diameter (D50), which is effective for improving the light emission efficiency, and improves the production efficiency and the light emission efficiency when using phosphor particles having a large average particle diameter (D50). An object of the present invention is to provide a light-emitting device that solves the problems and is excellent in manufacturability and excellent in luminous efficiency. It is another object of the present invention to provide a method for manufacturing such a light emitting device.

  The light-emitting device according to claim 1 is a substrate having a recess; a light-emitting element disposed in the recess; phosphor particles having an average particle diameter (D50) of 15 μm or more and 30 μm or less, and a viscosity before curing of 1 Pa. A phosphor layer having a transparent resin of s to 3 Pa · s and filled in the recess.

  The method for manufacturing a light emitting device according to claim 2 is a mixture of phosphor particles having an average particle diameter (D50) of 15 μm or more and 30 μm or less and a liquid transparent resin having a viscosity of 1 Pa · s or more and 3 Pa · s or less. And a step of injecting and curing the mixture into a recess provided in a substrate and having at least a light emitting element disposed therein to form a phosphor layer. .

  The light-emitting device according to claim 3 is a plurality of light-emitting elements; a reflective layer formed in a size that allows the light-emitting elements to be arranged at intervals with a white insulating material; A circuit pattern electrically connected to the light emitting element; a translucent adhesive layer for adhering the plurality of light emitting elements on the same surface of the reflective layer in the vicinity of the circuit pattern; and an average particle diameter (D50) of 15 μm or more A phosphor layer of 30 μm or less and a transparent resin having a viscosity before curing of 1 Pa · s or more and 3 Pa · s or less, and disposed on the reflective layer. Features.

  The light emitting device according to claim 4 is the light emitting device according to any one of claims 1 to 3, wherein the phosphor includes a yellow phosphor and at least one phosphor of an orange phosphor and a red phosphor. It is characterized by being. In order to improve the average color rendering index Ra to be, for example, 90 or more, an orange phosphor or a red phosphor may be included, and it is more preferable to mix an orange phosphor or a red phosphor.

  Unless otherwise specified, the definitions and technical meanings of terms in the above-described inventions are as follows.

  A base material is comprised from the flame | frame which has the board | substrate which has wiring parts, such as a circuit pattern and a lead terminal, for example, and the recessed part provided on this board | substrate and opened outside. Within this recess, a light emitting element and a phosphor layer are arranged in this order from the bottom to the top. In addition, you may form a base material by forming a recessed part on a board | substrate, without using a flame | frame.

  The light emitting element emits visible light by exciting phosphor particles with emitted light. Examples of the light emitting device used in the present invention include a blue light emitting type LED chip and an ultraviolet light emitting type LED chip. However, the present invention is not limited to these, and any light emitting element capable of emitting visible light by exciting phosphor particles can emit various light emission depending on the use of the light emitting device, the intended emission color, and the like. An element can be used. A nitride semiconductor can be preferably used. In addition, a III-V group compound semiconductor, a II-IV group compound semiconductor, an IV-VI group compound semiconductor, or the like can also be used. The light emitting color of the light emitting element may be any of blue, red and green, and the light emitting color of each light emitting element used may be different for each light emitting element or all may be the same.

  A fluorescent substance layer seals the light emitting element arrange | positioned in the recessed part of a base material, has a fluorescent substance particle and transparent resin, and is filled in the recessed part. This phosphor layer is formed by injecting and curing a mixture mainly composed of phosphor particles and a liquid transparent resin in a recess. The phosphor particles are excited by the light emitted from the light emitting element to emit visible light, and are mixed by the color mixture of the visible light emitted from the phosphor particle and the light emitted from the light emitting element, or from the phosphor particles. A desired light-emitting color is obtained as a light-emitting device by color mixing of visible light or visible light itself.

  The phosphor particles used for forming the phosphor layer have an average particle diameter (D50) of 15 μm or more and 30 μm or less from the viewpoint of luminous efficiency. The kind of the phosphor constituting the phosphor particles is not particularly limited, and is appropriately selected according to the intended emission color, light emitted from the light emitting element, and the like.

  The liquid transparent resin used for forming the phosphor layer has a viscosity in the range of 1 Pa · s to 3 Pa · s. In addition, this viscosity is a viscosity measured at 25 degreeC. The liquid transparent resin is, for example, an epoxy resin or a silicone resin, and may be composed of only one of these, or may be composed of two or more. When a liquid transparent resin consists of 2 or more types of liquid transparent resins, let viscosity be the viscosity of the mixture at the time of mixing 2 or more types of liquid transparent resins.

  The reflection layer formed of a white insulating material is preferably closer to 100% if the reflectance is 85% or more in the wavelength region of 400 nm to 740 nm. As this type of white insulating material, a sheet base material such as paper or cloth is impregnated with a thermosetting resin mixed with at least one of white powders such as aluminum oxide, titanium oxide, magnesium oxide and barium sulfate. The adhesive sheet which can be mentioned can be mentioned.

  For the light-transmitting adhesive layer, for example, an epoxy resin, a urea resin, an acrylic resin, or a silicone resin die bond material can be used. If the thickness of the adhesive layer is 5 μm or less and the light transmittance is 70% or more, the closer to 100%, the better. As this type of adhesive layer, a silicone resin adhesive layer can be particularly preferably used. Silicone resin-based adhesive layers have high light transmittance for light in almost all wavelength ranges from ultraviolet to visible light, and are unlikely to deteriorate such as discoloration even when irradiated with light having a relatively short wavelength for a long time. Excellent in terms. Note that low-melting glass can be used as the light-transmitting adhesive layer instead of the above polymer adhesive.

  The circuit pattern can be suitably formed from a metal foil such as a copper foil provided on the reflective layer by etching or the like, or a conductor attached by an adhesive. This circuit pattern is electrically connected to a plurality of light emitting elements by wire bonding or the like, and is provided by connecting the plurality of light emitting elements in series, in parallel, or in series-parallel. Furthermore, in the present invention, it is preferable to provide a translucent sealing member that covers one surface of the reflective layer on which a plurality of light emitting elements are mounted and seals each light emitting element, but this sealing member is not indispensable. Absent.

  According to the light emitting device of claim 1, the transparent resin forming the phosphor layer has a viscosity before curing of 1 Pa · s or more and 3 Pa · s or less, so that the average particle diameter (D50) Even when large phosphor particles are used, clogging of the nozzles of the dispenser during the production can be suppressed, and discharge can be performed appropriately, so that the productivity can be improved. In addition, by using such a transparent resin, even when phosphor particles having a large average particle diameter (D50) are used, the phosphor particles settle between injection into the recesses during curing and curing. Since deposition can be suppressed, a light-emitting device with excellent light-emitting efficiency can be obtained. Therefore, according to the light emitting device of the first aspect, since it is possible to suppress a decrease in luminous efficiency due to sedimentation and deposition when using phosphor particles having a large average particle diameter (D50), such phosphor particles are inherently used. The effect of improving the luminous efficiency can be sufficiently obtained, and the productivity can also be improved.

  According to the method for manufacturing a light-emitting device according to claim 2, phosphor particles having a large average particle diameter (D50) are obtained by using a liquid transparent resin having a specific viscosity as the phosphor layer used for forming the phosphor layer. Even in the case of using the light emitting device, clogging at the nozzle of the dispenser can be suppressed and ejection can be performed appropriately, so that the light emitting device can be manufactured with high yield. In addition, by using such a liquid transparent resin, even when phosphor particles having a large average particle diameter (D50) are used, the phosphor particles settle and deposit after being injected into the recesses and before being cured. Since this can be suppressed, a light emitting device with excellent luminous efficiency can be manufactured.

  According to the light emitting device of claim 3, the plurality of light emitting elements are connected to the reflective layer by connecting to the circuit pattern formed on the white reflective layer and bonding each light emitting element with the light-transmitting adhesive layer. Are arranged side by side on the same plane. Further, by using a liquid transparent resin having a specific viscosity as the phosphor layer used for forming the phosphor layer, it is possible to cover the light emitting elements arranged side by side on the same surface of the reflective layer, so that the yield of the light emitting device can be increased. Can be manufactured well. In addition, by using such a liquid transparent resin, even when phosphor particles having a large average particle diameter (D50) are used, the phosphor particles settle and deposit after being injected into the recesses and before being cured. This can be suppressed.

  In order to improve the average color rendering index Ra, for example, 90 or more, the light emitting device according to claim 4 may include an orange phosphor or a red phosphor, and the orange phosphor or the red phosphor may be included. It can be more suitably mixed.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an example of an LED lamp as a light emitting device of the present invention. FIG. 2 is an example of an LED module in which a plurality of LED lamps shown in FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG.

  The LED lamp 1 shown in FIGS. 1 to 3 has an LED chip 2 as a light emitting element. As the LED chip 2, for example, a blue light emitting type LED chip, an ultraviolet light emitting type LED chip, or the like is used. The LED chip 2 is mounted on a circuit pattern 8 provided on a substrate 5 via an electrical insulating layer 4, and a lower electrode is electrically connected thereto. The upper electrode of the LED chip 2 is electrically connected to another circuit pattern 8 by a conductive wire.

  On the substrate 5, there is provided a frame 6 that forms a cavity 3 (concave portion) that opens upward in a truncated cone shape. The LED chip 2 is disposed in the cavity 3. A phosphor layer 9 is formed in the cavity 3 in which the LED chip 2 is disposed, and the LED chip 2 is covered with the phosphor layer 9.

  The phosphor layer 9 is obtained by dispersing phosphor particles in a transparent resin. The electrical energy applied to the LED lamp 1 is converted into blue light or ultraviolet light by the LED chip 2, and the light is converted into long wavelength light by the phosphor particles contained in the phosphor layer 9. Then, a color based on the color of light emitted from the LED chip 2 and the emission color of the phosphor particles, for example, white light, is emitted from the LED lamp 1.

  The phosphor particles constituting the phosphor layer 9 are excited by light emitted from the LED chip 2, such as blue light or ultraviolet light, and emit visible light. The kind of the phosphor constituting the phosphor particles is appropriately selected according to the emission color of the target LED lamp 1.

For example, when white light emission is obtained using a blue light emitting type LED chip 2, yellow phosphor particles that are excited by blue light from the LED chip 2 and emit yellow light or orange light are mainly used. Further, in order to improve color rendering properties, red phosphor particles may be used in addition to yellow phosphor particles. Examples of yellow phosphor particles include YAG phosphors such as RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd, and La; the same applies hereinafter), AE, and the like. ₂ SiO ₄ : Eu phosphor (AE is an alkaline earth element such as Sr, Ba, Ca, etc .; the same shall apply hereinafter) or the like, and those made of silicate phosphors are used.

When white light emission is obtained using the ultraviolet light emitting type LED chip 2, RGB phosphor particles are mainly used. Examples of the blue phosphor particles include halophosphate phosphors such as AE ₁₀ (PO ₄ ) ₆ Cl ₁₂ : Eu phosphor and aluminate fluorescence such as (Ba, Mg) Al ₁₀ O ₁₇ : Eu phosphor. What consists of a body etc. is used. As the green phosphor particles, particles made of aluminate phosphor such as (Ba, Mg) Al ₁₀ O ₁₇ : Eu, Mn phosphor are used. As the red phosphor particles, those made of an oxysulfide phosphor such as a La ₂ O ₂ S: Eu phosphor are used.

Furthermore, in addition to the phosphor particles as described above, nitride phosphors (for example, AE ₂ Si ₅ N ₈ : Eu) and oxynitride phosphors (for example, Y) that can obtain various emission colors depending on the composition. ₂ Si ₃ O ₃ N _8c e), a sialon-based phosphor (for example, AE _x (Si, Al) ₁₂ (N, O) ₁₆ : Eu) and the like may be applied. The LED lamp 1 is not limited to the white light emitting lamp, and the LED lamp 1 having a light emitting color other than white can be configured. When the LED lamp 1 emits light other than white, for example, light of an intermediate color, various phosphor particles are appropriately used according to the target light emission color.

  The average particle diameter (D50) of the phosphor particles is 15 μm or more and 30 μm or less from the viewpoint of improving the luminous efficiency of the LED lamp 1 and the like. The average particle diameter (D50) is measured by a laser diffraction method, and indicates the size of particles that are accumulated from a low particle diameter and reach 50% by volume of the total amount of phosphor. When the average particle diameter (D50) of the phosphor particles is less than 15 μm, it is difficult to obtain sufficient light emission efficiency. On the other hand, if it exceeds 30 μm, the gap between the phosphor particles becomes large, and it becomes difficult to obtain a desired color temperature unless the blending ratio of the phosphor particles to the transparent resin is increased, and as described above, sedimentation occurs. It becomes easy. The average particle diameter (D50) of the phosphor particles is preferably 20 μm or more and 30 μm or less.

  The average particle diameter (D50) of the phosphor particles can be controlled, for example, by performing a classification process such as sieving in the manufacturing process. When an RGB phosphor or the like is applied to the phosphor, phosphor particles having an average particle diameter (D50) of 15 μm or more and 30 μm or less are used for each of blue, green, and red phosphors. The same applies to the case of using a mixture of two or more phosphors other than RGB phosphors.

  Moreover, as transparent resin which forms the fluorescent substance layer 9, a silicone resin, an epoxy resin, etc. are mentioned as a preferable thing, for example, These may use only 1 type and 2 or more types are used. Also good.

  Such a phosphor layer 9 is obtained by adding a phosphor particle to a liquid transparent resin such as a silicone resin or an epoxy resin and mixing the mixture, for example, a nozzle diameter of 0.15 to 0.45 mm, preferably 0.20 to 0. It is formed by putting in a dispenser having a nozzle of about 25 mm, discharging from the nozzle, pouring into the cavity 3 in which the LED chip 2 is arranged, and thermosetting.

  In the present invention, the phosphor particles used for forming such a phosphor layer 9 have an average particle diameter (D50) of 15 μm or more and 30 μm or less as described above, and the liquid transparent resin has a viscosity of 1 Pa · s to 3 Pa · s or less is used. In addition, when the liquid transparent resin used for forming the phosphor layer 9 is composed of two or more liquid transparent resins, the viscosity of the mixture when these two or more liquid transparent resins are mixed is as follows. It may be 1 Pa · s or more and 3 Pa · s or less.

  When the viscosity of the liquid transparent resin used to form the phosphor layer 9 is less than 1 Pa · s, when the mixture of the phosphor particles and the liquid transparent resin is injected into the cavity 3, the phosphor is cured before being cured. The particles settle and deposit on the bottom and the density increases, resulting in a decrease in luminous efficiency. The effect of using phosphor particles with a large average particle diameter (D50) effective for improving luminous efficiency is fully exhibited. Not.

  On the other hand, when the viscosity of the liquid transparent resin exceeds 3 Pa · s, when the mixture of the phosphor particles and the liquid transparent resin is put into the dispenser and discharged from the nozzle, the nozzle is clogged, and the mixture enters the cavity 3. Can not be injected, or even if it can be injected, the amount thereof may be insufficient, resulting in a decrease in manufacturability.

  In the present invention, a liquid transparent resin for forming the phosphor layer 9 having a specific viscosity is used due to problems such as sedimentation and clogging while being effective for improving luminous efficiency. Phosphor particles having a large average particle diameter (D50), which has been difficult, can be used, and a light-emitting device that is excellent in manufacturability and excellent in luminous efficiency can be obtained.

  As the phosphor particles used for forming the phosphor layer 9, various phosphor particles as described above can be used. At this time, the specific gravity and the like of the phosphor particles vary depending on the type thereof, but in the present invention, the phosphor particles generally used for such applications are not particularly limited and can be widely used.

For example, as yellow to orange light emitting phosphor particles used for obtaining white light emission using a blue light emitting type LED chip 2, for example, RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE is Y, YAG phosphor such as AE ₂ SiO ₄ : Eu phosphor (AE is an alkaline earth element such as Sr, Ba, Ca, etc. The same shall apply hereinafter) such as at least one selected from Gd and La. The thing which consists of silicate fluorescent substance of this is mentioned. The specific gravity of these phosphor particles is slightly different from 4.5 to 5.0 and 3.0 to 4.0, respectively. However, even in such a case, by setting the viscosity of the liquid transparent resin as described above, the sedimentation and deposition of the phosphor particles in the cavity 3 can be sufficiently suppressed. Clogging and the like in the nozzle can be sufficiently suppressed. Therefore, the phosphor particles are less likely to settle and accumulate, and a decrease in luminous efficiency can be suppressed. Inclusion of a red phosphor or the like tends to lower the luminous efficiency. However, if the sedimentation and deposition of the phosphor particles are suppressed as described above, the average color rendering index Ra is suppressed while suppressing the decrease in the luminous efficiency. Can be improved. For example, in order to set the average color rendering index Ra90 or more, it is preferable to include an orange phosphor or a red phosphor, and it is more preferable to mix an orange phosphor or a red phosphor.

  Further, the content of the phosphor particles (the content of the phosphor particles in the mixture of the phosphor particles and the liquid transparent resin) varies slightly depending on the type, average particle diameter (D50), etc. The content is not particularly limited as long as the amount is within the range.

  For example, the content of the phosphor particles in the mixture of the phosphor particles and the liquid transparent resin is usually in the range of 10% by weight or more and 20% by weight or less. By setting the viscosity as described above, sedimentation and deposition of the phosphor particles in the cavity 3 can be sufficiently suppressed, and clogging in the nozzle of the dispenser can be sufficiently suppressed.

  The present invention has been described above. However, the present invention is not necessarily limited to the above-described one, and the configuration thereof can be changed as necessary as long as it does not contradict the gist of the present invention. it can. For example, in the above-described example, a plurality of LED lamps 1 are arranged in a matrix as the LED module 10. For example, a plurality of LED lamps 1 may be formed in a row, or only one LED lamp may be formed. May be used independently.

  Next, a light emitting device showing a second embodiment of the present invention in which a plurality of LED chips are arranged in a matrix in one cavity (concave portion) will be described. Reference numeral 20 in FIGS. 4 and 5 denotes a light emitting device that forms an LED package. The light emitting device 20 includes an LED chip 2 as a plurality of light emitting elements, a phosphor layer 3, a reflective layer 4, a device substrate 5 as a base material, a reflector 6 as a frame, a circuit pattern 8, a transparent pattern. The optical adhesive layer 21 and the light diffusion member 22 are provided. The device substrate 5 and the reflector 6 cooperate to constitute a cavity (concave portion) 3.

  The device substrate 5 is made of a flat plate made of a metal or an insulating material such as a synthetic resin, and has a predetermined shape such as a rectangular shape in order to obtain a light emitting area required for the light emitting device 20. When the device substrate 5 is made of a synthetic resin, it can be formed of, for example, an epoxy resin containing glass powder. When the device substrate 5 is made of metal, the heat radiation from the back surface of the device substrate 5 is good, and the emission color of the LED chip 2 that emits light in the same wavelength range as the temperature of each part of the device substrate 5 can be made uniform. It is preferable for suppressing the variation of. In order to suppress the variation, the device substrate 5 may be formed of a material having excellent thermal conductivity, for example, a material having a thermal conductivity of 10 W / m · K or more. Examples of such a material include a metal material such as aluminum or an alloy thereof. Can do.

  The reflective layer 4 has such a size that a predetermined number of LED chips 2 can be disposed, and is attached to the entire surface of the device substrate 5, for example. The reflective layer 4 is formed of a white insulating material having a reflectance of 85% or more in a wavelength region of 400 nm to 740 nm. The white insulating material forming the reflective layer 4 is formed by impregnating a sheet base material with a thermosetting resin mixed with white powder such as aluminum oxide. The reflective layer 4 is bonded to one surface which becomes the surface of the device substrate 5 by its own adhesiveness.

  The circuit pattern 8 is bonded to the surface of the reflective layer 4 opposite to the surface to which the device substrate 5 is bonded as an energizing element for each LED chip 2. For example, in order to connect the LED chips 2 in series, the circuit pattern 8 is formed in two rows scattered at predetermined intervals in the longitudinal direction of the device substrate 5 and the reflective layer 4 as shown in FIG. . The end side circuit pattern 8a located on one end side of one circuit pattern 8 row is formed integrally with a power feeding pattern portion 8c, and similarly, the end side located on one end side of the other circuit pattern 8 row. The circuit pattern 8a is integrally formed with a power feeding pattern portion 8d. The power feeding pattern portions 8 c and 8 d are provided side by side at one end in the longitudinal direction of the reflective layer 4, and are separated from each other and insulated by the reflective layer 4. Electric wires (not shown) reaching the power supply are individually connected to the power supply pattern portions 8c and 8d by soldering or the like.

  Each LED chip 2 is made of a double-wire type LED chip using, for example, a nitride semiconductor, does not have a reflective film, and can emit light both in the thickness direction. Each LED chip 2 is disposed between circuit patterns 8 adjacent to each other in the longitudinal direction of the device substrate 5, and is bonded to the same surface of the white reflective layer 4 by a translucent adhesive layer 21. By this adhesion, the circuit pattern 8 and the LED chip 2 are arranged in a straight line on the same surface of the reflective layer 4, so that the side surfaces 5 a and 5 b of the LED chip 2 positioned in this arrangement direction and the circuit pattern 8 are close to each other. It is provided so as to face each other. The thickness of the translucent adhesive layer 21 is 5 μm or less. For the translucent adhesive layer 21, for example, a translucent adhesive having a thickness of 5 μm or less and a light transmittance of 70% or more, such as a silicone resin adhesive, can be suitably used.

  The electrode of each LED chip 2 and the circuit pattern 8 arranged close to both sides of the LED chip 2 are connected by a bonding wire 7 provided by wire bonding. Further, the end side circuit patterns located on the other end side of the two rows of circuit patterns 8 are also connected by wire bonding. Therefore, in this embodiment, each LED chip 2 is connected in series.

  The reflectors 6 are not individually provided for each one or several LED chips 2, but are a single one surrounding all the LED chips 2 on the reflective layer 4, and are shown in a frame, for example, FIG. It is formed with a rectangular frame. The reflector 6 is bonded to the reflective layer 4, and a plurality of LED chips 2 and circuit patterns 8 are housed therein, and the pair of power supply pattern portions 8 c and 8 d are positioned outside the reflector 6. Yes.

  The reflector 6 is formed of, for example, a synthetic resin, and its inner peripheral surface is a reflective surface. The reflective surface of the reflector 6 can be formed by depositing or plating a metal material having a high reflectivity such as Al or Ni, or can be formed by applying a white paint having a high visible light reflectivity. Alternatively, white powder can be mixed into the molding material of the reflector 6 to make the reflector 6 itself white with high visible light reflectance. As said white powder, white fillers, such as aluminum oxide, titanium oxide, magnesium oxide, barium sulfate, can be used. In addition, it is desirable to form the reflecting surface of the reflector 6 so as to gradually open in the irradiation direction of the light emitting device 20.

  The phosphor layer 9 is made of a translucent material such as a transparent silicone resin or transparent glass. The phosphor particles used to form the phosphor layer 9 have an average particle diameter (D50) of 15 μm or more and 30 μm or less as described above, and the liquid transparent resin has a viscosity of 1 Pa · s or more and 3 Pa · s. The following are used. The liquid transparent resin containing the phosphor is solidified in the reflector 6 by evenly filling the surface of the reflective layer 4 and the LED chips 2 and bonding wires 7 arranged in a straight line. It is considered that the liquid transparent resin that has flowed between the surface of the reflective layer 4 and the bonding wire 7 has spread to each LED chip 2 and the bonding wire 7 due to a capillary phenomenon or the like. In addition, when the liquid transparent resin used for forming the phosphor layer 9 is composed of two or more liquid transparent resins, the viscosity of the mixture when these two or more liquid transparent resins are mixed is as follows. It may be 1 Pa · s or more and 3 Pa · s or less. For example, in the present embodiment in which each LED chip 2 is a blue LED chip, a phosphor (illustrated) that converts the wavelength of primary light (blue) emitted from these elements to produce yellow light as secondary light having a different wavelength. However, as a preferred example, it is mixed in a substantially uniformly dispersed state.

  By this combination, while a part of the blue light emitted from the LED chip 2 passes through the phosphor layer 3 without hitting the phosphor, the phosphor hit by the blue light emitted from the LED chip 2 is Since the yellow light is absorbed and the yellow light is transmitted through the phosphor layer 3, the white light of the light emitting device 20 can be realized by mixing these two complementary colors.

  The light diffusing member 22 combined with the surface light source 20 has a flat plate shape and is disposed in front of the reflector 6. The reflector 6 may be provided with an extension projecting forward thereof to support the light diffusion member 22 there, or may be supported by a lighting fixture body (not shown) containing the light emitting device 20.

  The light diffusion member 22 has a difference between the transmittance of blue light of 400 nm to 480 nm and the transmittance of yellow light of 540 nm to 650 nm within 10%, and the transmittance of visible light is 90% or more 100 Those having a light diffusion performance of less than% can be suitably used. By using such a light diffusing member 22, the blue primary light and the yellow secondary light can be mixed by the light diffusing member 22, and the light diffusing member 22 can be white in which the color unevenness is suppressed.

  Next, the present invention will be described in detail with reference to examples.

Add phosphor particles whose average particle diameter (D50) is changed in the range of 15 μm or more and 30 μm or less in the liquid transparent resin whose viscosity is changed in the range of 0.3 Pa · s or more and 10.0 Pa · s or less. And mixed to prepare a mixture. The liquid transparent resin was composed of two types of silicone resins, and the viscosity was measured when two types of silicone resins were mixed. The phosphor particles were YAG phosphors of (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce composition. And the content of the phosphor particles in the mixture of the phosphor particles and the liquid transparent resin is within the range of 10 wt% or more and 20 wt% or less, and the luminous efficiency according to the average particle diameter (D50) of the phosphor particles. The content was set so as to be the highest.

Next, the mixture of this fluorescent substance particle and liquid transparent resin was put into the dispenser which has a nozzle with a nozzle diameter of 250 micrometers, and it was observed whether the mixture was actually discharged from a dispenser. The results are shown in Table 1. In the table, “◯” indicates that the mixture was properly discharged from the nozzle, “△” indicates that the nozzle is slightly clogged, and “×” indicates that the nozzle is completely clogged and the mixture is This indicates what was not discharged.

Separately, the mixture was injected into the cavity 3 and cured, and the presence or absence of sedimentation of the phosphor particles was observed. Presence or absence of sedimentation was performed by cutting the cavity 3 in which the mixture was cured in the vertical direction and observing the cross section. Here, the mixture was injected so as to have a height of 700 μm from the surface of the LED chip 2. The results are shown in Table 2. In the table, “◯” indicates that the phosphor particles did not settle, “Δ” indicates that the phosphor particles slightly settled, and “×” indicates that the phosphor particles completely settled. Show things.

Further, the light emission efficiency at a color temperature of 6700 K was measured by applying blue light to the YAG phosphor powder. The luminous efficiency was measured by changing the average particle size (D50) of the YAG phosphor powder in the range of 5 μm to 30 μm. In the table, the luminous efficiency is expressed as a relative value with respect to 100 when the average particle diameter (D50) of the phosphor particles is 10 μm.

  As is apparent from the results shown in Table 3, it was confirmed that the luminous efficiency can be improved by setting the average particle diameter (D50) of the phosphor particles to 15 μm or more and 30 μm or less. As is apparent from the results shown in Tables 1 and 2, even when such phosphor particles having a large average particle diameter (D50) are used, the viscosity of the liquid transparent resin is 1 Pa · s or more and 3 Pa. It was confirmed that by setting it to s or less, clogging at the nozzle of the dispenser can be suppressed, and sedimentation and accumulation in the cavity 3 can also be suppressed.

  Therefore, in the present invention, by using a liquid transparent resin having a viscosity of 1 Pa · s or more and 3 Pa · s or less, even when such a phosphor particle having a large average particle diameter (D50) is used, It is possible to suppress clogging in the nozzle, settling and accumulation in the cavity 3, and to be excellent in manufacturability, as well as the luminous efficiency inherent in such phosphor particles having a large average particle diameter (D50). The effect of improvement can be sufficiently obtained, and the light emission efficiency can be improved.

Sectional drawing which shows an example of the LED lamp as a light-emitting device of this invention. The top view which shows an example of the LED module which has arrange | positioned two or more LED lamps shown in FIG. AA 'line sectional drawing of the LED module shown in FIG. The top view which shows 2nd Embodiment of the LED lamp as a light-emitting device of this invention. F2-F2 sectional drawing of the LED lamp shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LED lamp, 2 ... LED chip, 3 ... Cavity (recessed part), 4 ... Electrical insulation layer, 5 ... Board | substrate, 6 ... Frame, 7 ... Conductive wire, 8 ... Circuit pattern, 9 ... Phosphor layer, 10 ... LED module.

Claims (4)

A substrate having a recess;
A light emitting device disposed in the recess;
A phosphor layer having phosphor particles having an average particle diameter (D50) of 15 μm or more and 30 μm or less and a transparent resin having a viscosity before curing of 1 Pa · s or more and 3 Pa · s or less, and filled in the recesses When;
A light-emitting device comprising: Mixing phosphor particles having an average particle diameter (D50) of 15 μm or more and 30 μm or less with a liquid transparent resin having a viscosity of 1 Pa · s or more and 3 Pa · s or less to obtain a mixture;
A step of injecting and curing the mixture into a recess provided in a substrate and having at least a light emitting element disposed therein to form a phosphor layer;
A method of manufacturing a light emitting device, comprising: A plurality of light emitting elements;
A reflective layer formed in a size that allows the light emitting elements to be arranged side by side with a white insulating material;
A circuit pattern formed on the reflective layer and electrically connected to the light emitting element;
A translucent adhesive layer for adhering the light emitting elements on the same surface of the reflective layer in the vicinity of the circuit pattern;
A fluorescent particle having an average particle diameter (D50) of 15 μm or more and 30 μm or less and a transparent resin having a viscosity before curing of 1 Pa · s or more and 3 Pa · s or less, and disposed on the reflective layer. Body layers;
A light-emitting device comprising:   4. The light emitting device according to claim 1, wherein the phosphor includes a yellow phosphor and at least one phosphor of an orange phosphor and a red phosphor. 5.

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