JP2013168528A - Method for manufacturing light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing light-emitting device capable of forming a phosphor layer without heating a light-emitting element when applying a phosphor dispersion liquid onto the light-emitting element.SOLUTION: A method for manufacturing a light-emitting device having a light-emitting element which emits light of a prescribed wavelength and a wavelength conversion unit which emits a fluorescence having a wavelength different from the prescribed wavelength comprises a step of forming the wavelength conversion unit, including a step of applying a phosphor dispersion liquid including a phosphor, an inorganic fine particle, a suspending agent, and a solvent onto the light-emitting element by intermittently spraying the liquid toward the light-emitting element.

Description

  The present invention relates to a technique for applying a phosphor on a light emitting element in a light emitting device.

  In recent years, a technology for obtaining a white light emitting device in which a phosphor such as a YAG (yttrium, aluminum, garnet) phosphor is arranged in the vicinity of a gallium nitride (GaN) blue LED (Light Emitting Diode) chip has been widely used. It has been. In such a white light emitting device, white light is emitted by a color mixture of blue light emitted from the blue LED chip and yellow light emitted when the phosphor receives blue light and emits secondary light. In addition, a technique of emitting white light by mixing color of blue light emitted from the blue LED chip and red light and green light emitted by each phosphor receiving blue light and secondary light emission is also used. Yes.

  Such white light emitting devices have various uses, for example, there is a demand as an alternative to fluorescent lamps and incandescent lamps. In addition, it is also being used for lighting devices such as automobile headlights that require extremely high luminance.

  In such a white LED, a method of sealing an LED chip or a mounting portion using a transparent resin in which a phosphor is dispersed is generally used. However, since the optical path length passing through the sealing resin varies depending on the radiation angle, there is a problem that the color varies depending on the radiation angle.

  In order to deal with this problem, studies have been made to form a wavelength conversion layer with a uniform film thickness on a light emitting element by spray-coating a phosphor solution directly on the light emitting element.

WO2011 / 083841 Patent 3925137

Since the phosphor liquid contains a solvent, if the drying property at the time of spraying is low, it is affected by the liquid flow, surface tension, etc., and the adhesion to the side surface of the light emitting element and the corner edge portion is deteriorated.
For this reason, in all the conventional examples, the drying property was improved by heating the substrate (the object to be coated) during spray coating.

  However, when the phosphor dispersion liquid is applied, if the light-emitting element itself is heated, a large amount of solvent may volatilize in the vicinity of the heating element, so that strict explosion-proof measures are required. In addition, since it is necessary to exhaust the volatilized solvent through a duct, it is difficult to make the system in an inert gas atmosphere, resulting in heating in the presence of oxygen, and metal parts such as electrodes and reflective layers. There is a risk of promoting oxidation.

  An object of the present invention is to provide a production method capable of forming a phosphor layer without heating a light emitting element when a phosphor dispersion liquid is applied on the light emitting element.

The invention according to claim 1 includes: a light emitting element that emits light having a predetermined wavelength; and a wavelength conversion unit that receives light emitted from the light emitting element and emits fluorescence having a wavelength different from the predetermined wavelength. A method of manufacturing a light emitting device comprising: a phosphor dispersion liquid containing phosphor, inorganic fine particles, a suspending agent, and a solvent is sprayed intermittently toward the light emitting element and applied onto the light emitting element. A method for manufacturing a light-emitting device, comprising the steps of forming the wavelength conversion section.
The invention described in claim 2 is the method for manufacturing the light emitting device according to claim 2, wherein the solvent includes a first solvent including an alcohol having a boiling point of less than 100 ° C., and a boiling point. And a second solvent configured to contain water or alcohol at 100 ° C. or higher.
Moreover, invention of Claim 3 is a manufacturing method of the light-emitting device of Claim 2, Comprising: The said solvent is the 1st solvent comprised including the alcohol whose boiling point is less than 100 degreeC, and a boiling point. And a second solvent configured to contain water or alcohol at 100 ° C. or higher.
The invention according to claim 4 is the method for manufacturing the light emitting device according to claim 3, wherein the component weight M1 of the first solvent and the component weight M2 of the second solvent are M2 ≦ It satisfies the condition of M1 ≦ M2 × 2.
Moreover, invention of Claim 5 is a manufacturing method of the light-emitting device as described in any one of Claims 1-4, Comprising: The said precipitation inhibitor contains a layered silicate mineral. Features.
The invention according to claim 6 is the method for manufacturing the light emitting device according to any one of claims 1 to 5, wherein in the step, the organic dispersion is applied after the phosphor dispersion liquid is applied. The method includes a step of applying a ceramic precursor liquid containing a metal compound on the light emitting device.
The invention according to claim 7 is the method for manufacturing the light emitting device according to any one of claims 1 to 6, wherein in the step, the discharge of the phosphor dispersion liquid and the stop thereof are performed. By repeating the above, the intermittent spraying is performed, and the ejection time T1 satisfies the condition of 5 [ms] ≦ T1 ≦ 1000 [ms].
The invention according to claim 2 is the method for manufacturing the light emitting device according to claim 7, wherein 0 [ms] <T2 ≦ 1000 during the period when the discharge of the phosphor dispersion liquid is stopped. Air is sprayed on the light emitting element in a range of time T2 that satisfies the condition of [ms].
The invention according to claim 9 is the method for manufacturing the light emitting device according to claim 7 or claim 8, wherein the period T3 for repeating the discharge and stop is 50 [ms] ≦ T3 ≦ 2000 [ms. ] Is satisfied.
The invention according to claim 10 is the method for manufacturing a light emitting device according to any one of claims 1 to 9, wherein the light emitting element is formed in a plate shape having an upper surface and a side surface. In the step, the phosphor dispersion liquid is ejected in a direction inclined by a predetermined angle θ1 with respect to the normal direction of the upper surface, and is applied onto the light emitting element.
The invention according to claim 11 is the method for manufacturing the light emitting device according to claim 10, wherein the angle θ1 satisfies a condition of 20 ° ≦ θ1 ≦ 70 °.
The invention described in claim 12 is the method for manufacturing the light emitting device according to claim 10, wherein the angle θ1 satisfies a condition of 45 ° ≦ θ1 ≦ 70 °.
The invention according to claim 13 is the method for manufacturing a light emitting device according to any one of claims 10 to 12, wherein the light emitting element has a rectangular shape on the upper surface, There are four side surfaces around the upper surface, and in the step, the direction in which the phosphor dispersion liquid is discharged and the direction in which the bisector of the angle formed by the two adjacent side surfaces is extended are the method described above. Applying the phosphor dispersion liquid to the upper surface and the two side surfaces by spraying an angle θ2 formed on a surface perpendicular to the linear direction satisfying a condition of −25 ° ≦ θ2 ≦ 25 °. Features.
The invention described in claim 14 is the method for manufacturing the light emitting device according to claim 13, wherein the phosphor dispersion liquid is applied to the upper surface and the two side surfaces, and then the direction of the light emitting element is set. And the phosphor dispersion liquid is applied to the other two side surfaces opposite to the two side surfaces and the upper surface. To do.
The invention according to claim 15 is the method for manufacturing the light emitting device according to claim 13, wherein the phosphor dispersion liquid is applied to the upper surface and the two side surfaces, and then the direction of the light emitting element is set. Is rotated 90 ° about the normal direction of the upper surface, and the phosphor dispersion liquid is applied to the other two side surface sets different from the two side surface sets and the upper surface. To do.

  According to this invention, by applying the phosphor dispersion liquid intermittently, the drying property of the phosphor dispersion liquid applied immediately before is promoted using the period when the discharge of the phosphor dispersion liquid is stopped. It becomes possible. Also, by blending multiple solvents with different boiling points, it becomes possible to promote drying while maintaining dispersion stability of the phosphor, and the combination of both eliminates the need for heating during spray coating. Is possible.

It is the schematic sectional drawing which showed the structure of the light-emitting device which concerns on this embodiment. It is the schematic which showed the structure of the fluorescent substance coating device which concerns on this embodiment. It is the schematic side view which showed the structure of the fluorescent substance coating device which concerns on this embodiment. It is the schematic top view which showed an example of the to-be-coated object in which the light emitting element was formed in the array form. It is the schematic which showed the one aspect | mode of the spray means. It is a schematic perspective view of a light emitting element. It is a figure for demonstrating the positional relationship of a nozzle and a light emitting element. It is a figure for demonstrating the positional relationship of a nozzle and a light emitting element. It is a figure for demonstrating the coating method in embodiment of this invention. It is a figure for demonstrating the coating method in embodiment of this invention. It is the flowchart which showed the flow of a series of processes concerning application | coating of a fluorescent substance dispersion liquid. It is an evaluation result of Example 1. It is an evaluation result of Example 2-1 and Example 2-2. It is the schematic sectional drawing which showed the general form of the light-emitting device which concerns on a comparative example. It is a figure for demonstrating the application | coating method in a modification. It is a figure for demonstrating the application | coating method in a modification. It is a figure for demonstrating the application | coating method in a modification. It is a figure for demonstrating the application | coating method in a modification. It is a figure for demonstrating the application | coating method in a modification. It is a figure for demonstrating the application | coating method in a modification.

(Configuration of light emitting device)
With reference to FIG. 1, the structure of the light-emitting device 50 produced | generated using the fluorescent substance coating device 1 which concerns on this invention is demonstrated. The light emitting device 50 includes a substrate 51, a metal portion 52 is provided at the bottom thereof, and a rectangular parallelepiped light emitting element 53 is disposed on the metal portion 52. The light emitting element 53 is an example of a light emitting element that emits light of a predetermined wavelength. A protruding electrode 54 is provided on the surface of the light emitting element 53 facing the metal part 52, and the metal part 52 and the light emitting element 53 are connected via the protruding electrode 54 (flip chip type). Here, a configuration in which one light emitting element 53 is provided for one substrate 51 is illustrated, but a plurality of light emitting elements 53 may be provided on one substrate 51.

  In the light emitting device 50 of the present embodiment, a blue light emitting element is used as the light emitting element 53. The blue light-emitting element is formed, for example, by stacking an n-GaN-based cladding layer, an InGaN light-emitting layer, a p-GaN-based cladding layer, and a transparent electrode on a sapphire substrate.

  A wavelength conversion unit 55 is formed on the substrate 51 so as to seal the periphery of the light emitting element 53. The wavelength conversion unit 55 is a translucent thin film configured as a translucent ceramic layer containing a phosphor (hereinafter, sometimes referred to as “transparent ceramic layer”). The thickness of the wavelength conversion unit 55 varies depending on the type of phosphor and the target emission color (chromaticity coordinate value), but is generally 1 to 200 μm, and preferably 10 to 50 μm. Here, the wavelength conversion unit 55 may be provided only on the upper surface and side surfaces of the light emitting element 53. As a method of providing the wavelength conversion unit 55 only around the light emitting element 53, a method of installing a mask when forming the wavelength conversion unit 55 is used. In the present embodiment, a thin film formed by applying a phosphor dispersion liquid and a ceramic precursor liquid and firing it is called a ceramic layer.

  Next, the configuration of the wavelength conversion unit 55 will be described in detail. The wavelength conversion unit 55 is formed by applying the phosphor dispersion liquid and the ceramic precursor liquid onto the light emitting element 53, and drying and baking the phosphor dispersion liquid and the ceramic precursor liquid. The phosphor dispersion liquid and the ceramic precursor liquid may be mixed in advance and applied as one liquid, or the ceramic precursor liquid may be applied after applying and drying the phosphor dispersion liquid. Hereinafter, the case where the phosphor dispersion liquid and the ceramic precursor liquid are separated is referred to as “two-liquid prescription”, and the case where the above-described separation is not performed is referred to as “one-liquid prescription”.

  As the phosphor dispersion liquid, a coating liquid in which a phosphor, an anti-settling material, and inorganic fine particles are dispersed in a solvent is used. In the present embodiment, it is desirable to use water or an alcohol solvent as the solvent. Water or alcohol-based solvents are easy to handle without odors, have high safety, and have a relatively low boiling point, so that they have good drying properties. As the alcohol solvent, alcohols such as methanol, ethanol, propanol, butanol, propylene glycol, and butanediol are preferable. These solvents may be used alone or in combination of two or more. Below, an example of the composition ratio of the solvent in this embodiment is demonstrated.

  As the solvent of the phosphor dispersion liquid according to the present embodiment, a solvent having a boiling point of less than 100 [° C.] and a solvent having a boiling point of 100 [° C.] or more are mixed and used. Although details will be described later, in the present embodiment, the phosphor dispersion liquid is applied by spraying without heating the light emitting element 53, and then this is baked to form the wavelength conversion unit 55. In order to eliminate the need for heating during spraying, the component ratio of the solvent (alcohol) of less than 100 [° C.] to the solvent (water or alcohol) of 100 [° C.] or higher is increased, and the phosphor dispersion using this solvent Increase dryness. Moreover, you may combine the low boiling point solvent whose boiling point is less than 100 [degreeC], the medium boiling point solvent which is 100 [degreeC] or more and less than 200 [degreeC], and the high boiling point solvent of 200 [degreeC] or more. Examples of the low boiling point solvent include methanol, ethanol, and isopropyl alcohol. Examples of the medium boiling point solvent include water, butanol, ethylene glycol, and propylene glycol. Examples of the high boiling point solvent include 1,3-butanediol, 1,4-butanediol, and glycerin. These low boiling point, medium boiling point, and high boiling point solvents may be used alone or in combination.

  Further, in combination with an anti-settling material (layered silicate) which will be described later, there is a thickening effect, and it is possible to form a coating solution with good dispersion stability without causing the phosphor to settle for a long period of time. Specifically, isopropyl alcohol having a lower boiling point is added among alcoholic systems. However, since isopropyl alcohol has a low viscosity, if the content is too large, the phosphor is precipitated. Therefore, it is desirable to use a mixed solvent in combination with a high viscosity alcohol solvent such as propylene glycol and butanediol.

  As an anti-settling material, it is desirable to use a layered silicate mineral. The layered silicate mineral is preferably a swellable clay mineral having a structure such as a mica structure, a kaolinite structure, or a smectite structure, and particularly preferably a smectite structure rich in swellability. This has the effect of increasing the viscosity of the liquid mixture in combination with the aforementioned water or alcohol solvent, and plays a major role in preventing the phosphor from settling.

  When the content of the layered silicate mineral in the ceramic layer is less than 0.5% by weight, the effect of increasing the viscosity of the mixed solution cannot be obtained sufficiently. On the other hand, when the content of the layered silicate mineral exceeds 20% by weight, the strength of the fired ceramic layer is lowered. Therefore, the content of the layered silicate mineral is preferably 0.5% by weight or more and 20% by weight or less, and more preferably 0.5% by weight or more and 10% by weight or less.

The ceramic precursor liquid contains a phosphor, a layered silicate mineral, and an organometallic compound that serves as a binder for sealing inorganic fine particles.
In the case of the one-liquid formulation, the ceramic precursor liquid is added to the phosphor dispersion liquid in advance. Examples of the organometallic compound used in the present embodiment include metal alkoxides, metal acetylacetonates, metal carboxylates, and the like, and metal alkoxides that are easily gelled by hydrolysis and polymerization reaction are preferable. As a result, a transparent ceramic layer (glass body) can be obtained by a so-called sol-gel method in which the phosphor dispersion liquid is sprayed and then heated in a gelation state and further baked. The transparent ceramic layer contains a phosphor, a layered silicate mineral, and inorganic fine particles, so that a strong phosphor dispersion film (wavelength conversion portion) can be formed. The manufacturing process can be simplified as compared with the case where the phosphor dispersion liquid and the organometallic compound are separately applied.

  The metal alkoxide may be a single molecule such as tetraethoxysilane, or may be a polysiloxane in which an organic siloxane compound is linked in a chain or a ring, but a polysiloxane that increases the viscosity of the mixed solution is preferable. In addition, there is no restriction | limiting in the kind of metal if a translucent glass body can be formed, but it is preferable to contain a silicon | silicone from a viewpoint of the stability of the glass body formed and the ease of manufacture. Moreover, you may contain multiple types of metal.

  In addition, when the amount of the organometallic compound mixed with the solvent is less than 5% by weight, it becomes difficult to increase the viscosity of the mixture, and when the amount of the organometallic compound exceeds 50% by weight, the polymerization reaction proceeds faster than necessary. End up. Therefore, the amount of the organometallic compound mixed with the solvent is preferably 5% by weight or more and 50% by weight or less, and more preferably 8% by weight or more and 40% by weight or less.

In addition, when the phosphor dispersion liquid contains an organometallic compound that is a ceramic precursor material, the reaction proceeds during storage of the coating liquid (that is, the phosphor dispersion liquid), the viscosity increases, and the coating property is increased. It may get worse. Moreover, the reaction of the ceramic precursor material is generally an irreversible reaction, and when the reaction of the organometallic compound that is the ceramic precursor material proceeds in the mixed solution containing the phosphor particles, the phosphor There is a possibility that all the liquid mixture containing the particles may become unusable.
Therefore, after applying and drying the phosphor dispersion liquid, a sol-like precursor liquid containing an organometallic compound may be applied onto the light emitting element (two-liquid formulation). In this way, the phosphor dispersion liquid and the ceramic precursor liquid are separated and applied in two steps, so that the storage stability of the phosphor dispersion liquid is improved and the reaction of the ceramic precursor material proceeds. Even in this case, the phosphor particles are not wasted. Hereinafter, the case where the phosphor dispersion liquid and the liquid containing the organometallic compound are separated may be referred to as “two-liquid formulation”, and the case where the above-described separation is not performed may be referred to as “one-liquid formulation”.

  The phosphor is excited by the wavelength of the light emitted from the light emitting element 53 (excitation wavelength) and emits fluorescence having a wavelength different from the excitation wavelength. In this embodiment, a YAG (yttrium, aluminum, garnet) phosphor that converts blue light (wavelength 420 nm to 485 nm) emitted from the blue light emitting element into yellow light (wavelength 550 nm to 650 nm) is used.

  Such phosphors use oxides of Y, Gd, Ce, Sm, Al, La, and Ga, or compounds that easily become oxides at high temperatures, and are mixed well in a stoichiometric ratio. A mixed raw material is obtained. Alternatively, a coprecipitated oxide obtained by calcining a solution obtained by coprecipitation of a solution obtained by dissolving a rare earth element of Y, Gd, Ce, or Sm in an acid with a stoichiometric ratio with oxalic acid, and aluminum oxide or gallium oxide. Mix to obtain a mixed raw material. Then, an appropriate amount of fluoride such as ammonium fluoride is mixed with the obtained mixed raw material as a flux and pressed to obtain a molded body. The obtained molded body is packed in a crucible and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a sintered body having phosphor emission characteristics. Next, the fired product is ball milled in water, washed, separated and dried, and finally passed through a sieve to obtain a desired phosphor.

  Further, the composition of the obtained phosphor was examined to confirm that it was a desired phosphor, and the emission wavelength in the excitation light of 465 nm was examined. As a result, it was confirmed that the peak wavelength was approximately 570 nm. That is, a phosphor that emits yellow light when irradiated with blue light can be obtained.

  In this embodiment, the YAG phosphor is used. However, the type of the phosphor is not limited to this. For example, other phosphors such as non-garnet phosphors containing no Ce are used. You can also. In addition, the larger the particle size of the phosphor, the higher the light emission efficiency (wavelength conversion efficiency). On the other hand, the gap generated at the interface with the organometallic compound becomes larger, and the film strength of the formed transparent ceramic layer is lowered. Accordingly, in consideration of the size of the gap generated at the interface between the light emission efficiency and the organometallic compound, it is preferable to use one having an average particle diameter of 1 μm or more and 50 μm or less. The average particle diameter of the phosphor can be measured, for example, by a Coulter counter method.

  The inorganic fine particles have a filling effect that fills the gap formed at the interface between the organometallic compound, the phosphor and the layered silicate mineral, a thickening effect that increases the viscosity of the mixed liquid before heating, and a transparent ceramic layer after firing. It has a film strengthening effect that improves the film strength. Examples of the inorganic fine particles used in the present invention include oxide fine particles such as silicon oxide, titanium oxide and zinc oxide, and fluoride fine particles such as magnesium fluoride. In particular, when a silicon-containing organic compound such as polysiloxane is used as the organometallic compound, it is preferable to use silicon oxide fine particles from the viewpoint of stability with respect to the formed transparent ceramic layer.

  When the content of the inorganic fine particles in the transparent ceramic layer is less than 0.5% by weight, the above-described effects cannot be sufficiently obtained. On the other hand, when the content of the inorganic fine particles exceeds 50% by weight, the strength of the fired ceramic layer is lowered. Therefore, the content of the inorganic fine particles in the transparent ceramic layer is preferably 0.5% by weight to 50% by weight, and more preferably 1% by weight to 40% by weight. The average particle diameter of the inorganic fine particles is preferably 0.001 μm or more and 50 μm or less in consideration of the above-described effects. The average particle diameter of the inorganic fine particles can be measured, for example, by a Coulter counter method.

  In consideration of the compatibility with the organometallic compound and the solvent, those obtained by treating the surface of the inorganic fine particles with a silane coupling agent or a titanium coupling agent can be used as appropriate.

  For example, when using a surface-treated lipophilic layered silicate mineral, the layered silicate mineral is premixed in a solvent, and then the phosphor and inorganic fine particles are added. Mix. When a hydrophilic layered silicate mineral that has not been surface-treated is used, first the layered silicate mineral and water are premixed, and then the phosphor and inorganic fine particles are mixed. Thereby, a layered silicate mineral can be mixed uniformly and the thickening effect can be heightened more. The preferred viscosity of the mixed solution is 25 to 800 cP, and the most preferred viscosity is 30 to 500 cP.

  The most preferable composition ranges of the above components contained in the phosphor dispersion liquid are 0.1 to 5% by weight of the layered silicate mineral and 1 to 40% by weight of the inorganic fine particles.

  In the case of a two-component formulation, the phosphor dispersion liquid obtained as described above is applied to the light emitting element 53 in a predetermined amount and dried, and then the ceramic precursor liquid is applied, dried and baked to obtain a fluorescent film having a predetermined film thickness. A body dispersion film (that is, wavelength conversion unit 55) is formed.

  In the case of a one-component formulation, when the above-described solution is prepared, a solution in which an organometallic compound that is a ceramic precursor is mixed with a solvent in advance is used. A predetermined amount of the phosphor dispersion containing the ceramic precursor is applied to the light emitting element 53, and then dried and fired to form a phosphor dispersion film (that is, the wavelength conversion unit 55) having a predetermined thickness.

  It should be noted that the environmental conditions of the present invention that are applied without heating are desirably an air temperature of 10 to 40 ° C. and a humidity of 20 to 80%, and among them, it is more desirable that the temperature is higher and the humidity is lower.

  Moreover, when the thickness of the formed phosphor dispersion film (that is, the wavelength converting portion 55) is less than 5 μm, the wavelength conversion efficiency is lowered and sufficient fluorescence cannot be obtained, and the thickness of the phosphor dispersion film is reduced to 500 μm. If it exceeds, the film strength is lowered and cracks and the like are likely to occur. Therefore, the thickness of the phosphor dispersion film is preferably 5 μm or more and 500 μm or less.

(Configuration of phosphor coating device)
Next, a method of spray coating the phosphor dispersion liquid on the light emitting element 53 in order to form the wavelength conversion unit 55 and a phosphor coating apparatus that realizes this will be described. In the conventional method, when the phosphor dispersion liquid is spray-coated on the light emitting element 53, the light emitting element is heated to improve the drying property, and the wavelength conversion unit 55 is formed. In the present embodiment, the phosphor dispersion liquid is intermittently applied to the light emitting element 53 by repeatedly discharging and stopping the phosphor dispersion liquid. By operating in this way, drying of the phosphor dispersion liquid is promoted while ejection is stopped, and the wavelength conversion unit 55 is formed without heating the light emitting element during application of the phosphor dispersion liquid. Hereinafter, the configuration of the phosphor coating apparatus according to the present embodiment will be described with reference to FIGS. 2A and 2B. FIG. 2A is a schematic diagram illustrating the configuration of the phosphor coating apparatus according to the present embodiment. 2A indicates the x direction, the vertical direction perpendicular thereto indicates the z direction, and the depth direction perpendicular to both the x direction and the z direction indicates the y direction. FIG. 2B is a schematic side view of the phosphor coating apparatus according to this embodiment as viewed from the x direction.

  The phosphor coating apparatus 1 according to this embodiment is an apparatus that coats the phosphor dispersion liquid onto the light emitting element 53 mounted on the substrate 51 by the spray means 12. As shown in FIGS. 2A and 2B, the phosphor coating apparatus 1 includes a spray unit 12, a stage 13, a support unit 11 for holding these in a predetermined position, an air supply unit 2, and a control unit 3. It is comprised including. The stage 13 holds the light emitting element 53 mounted on the substrate 51. 2A and 2B, only the light emitting element 53 is illustrated for easy understanding of the following description. The spray means 12 includes a tank 123 for storing the phosphor dispersion liquid, a nozzle 121 for spraying the phosphor dispersion liquid, and a pipe 122 for feeding the phosphor dispersion liquid from the tank 123 to the nozzle 121. It consists of

(Air supply part 2)
The air supply unit 2 is a supply unit that supplies air, and includes, for example, a pump. One end of each of the air supply pipes 21, 22 and 23 is connected to the air supply unit 2. The other end of the air supply pipe 22 is connected to the tank 123. That is, the air output via the air supply pipe 22 is supplied to the tank 123. Due to the pressure of the air, the phosphor dispersion liquid in the tank 123 is supplied to the nozzle 121 via the pipe 122. The other end of the air supply pipe 23 is supplied to the nozzle 121. By sequentially switching between air supply and stop, the valve at the tip of the nozzle is opened and closed, and the phosphor liquid supplied from the tank 123 when the nozzle is opened is Sprayed from 121. The other end of the air supply pipe 21 is connected to the nozzle 121. That is, the air output via the air supply pipe 21 is supplied to the nozzle 121 and only air is sprayed from the nozzle 121. The air supply unit 2 supplies air independently to each of the air supply pipes 21, 22, and 23, and the supply timing of the air to each is controlled by a discharge control unit 32 described later. Thereby, for example, the phosphor dispersion liquid can be intermittently sprayed from the nozzle 121 by sequentially switching the supply and stop of the air to the air supply pipe 23. Further, by supplying air to the air supply pipe 21 while the air supply to the air supply pipe 23 is stopped, only the air is discharged from the nozzle 121 while the spraying of the phosphor dispersion liquid is stopped. By spraying, drying of the applied phosphor dispersion liquid can be promoted.

  In this embodiment, the valve at the nozzle tip is opened and closed by air, but the valve in the nozzle 121 may be electrically opened and closed. In that case, instead of the air supply pipe 23, an electrical signal line is connected to the nozzle 121 from the control unit to control the timing of the air supply to the air supply pipe 21 and the timing of the electrical valve opening / closing signal. Therefore, intermittent spraying is possible.

(Control unit 3)
The control unit 3 includes a position control unit 31 and a discharge control unit 32.

  The position control unit 31 stores in advance control information indicating the relative positional relationship between the nozzle 121 and the stage 13 for each step for applying the phosphor dispersion liquid. The position control unit 31 controls the operation of each part of the support unit 11 described later based on this control information, and adjusts the position and orientation of the nozzle 121 and the stage 13. With respect to this relative positional relationship, relative to the stage 13, the relative position of the nozzle 121, the rotation of the nozzle 121 about the normal direction (z axis), and the light emitting element 53 on the stage 13. Control of the incident angle of the phosphor dispersion is included. Details of these operations will be described later together with the description of the support portion 11.

  The discharge controller 32 stores in advance control information indicating the timing at which each of the phosphor dispersion liquid and air is discharged from the nozzle 121. The discharge control unit 32 controls the operation of the air supply unit 2 at a timing based on this control information, and sprays the phosphor dispersion liquid or air from the nozzle 121. Specifically, the discharge control unit 32 instructs the air supply unit 2 to supply air to the air supply pipe 23 in accordance with the discharge timing of the phosphor dispersion liquid. In addition, the discharge control unit 32 instructs the air supply unit 2 to supply air to the air supply pipe 21 in synchronization with the air discharge timing.

  In the case where the phosphor dispersion liquid is applied intermittently, it is desirable that 5 [ms] ≦ T1 ≦ 1000 [ms], where T1 is a time for discharging the phosphor dispersion liquid. When T1 is longer than 1000 [ms], the discharge time of the phosphor dispersion liquid becomes too long, which is substantially the same as when the phosphor dispersion liquid is continuously discharged, and the drying property is poor. Because. Further, it is difficult to control the valve opening / closing timing of the air supply unit 2 with a cycle of less than 5 [ms]. Therefore, it is difficult to make T1 less than 5 [ms].

  Further, air may be sprayed from the nozzle 121 during the period when the discharge of the phosphor dispersion liquid is stopped. By operating in this way, drying of the phosphor dispersion applied to the light emitting element 53 can be promoted. Further, the phosphor dispersion liquid remaining at the tip of the nozzle 121 is discharged by air spraying. Thereby, the clogging of the nozzle 121 can be suppressed, and the stability of the application amount during intermittent application can be improved. In addition, when the time for spraying air is T2, it is desirable that 0 [ms] <T2 ≦ 1000 [ms]. This is because when T2 is longer than 1000 [ms], the dried phosphor dispersion liquid may be blown away with the atomized air.

  From the above, it is desirable that the period T3 for repeating the discharge and stop of the phosphor dispersion liquid is 50 [ms] ≦ T3 ≦ 2000 [ms]. The discharge stop period and the air output period may be changed in the above-described ranges of T1, T2, and T3 according to the viscosity of the phosphor dispersion liquid.

  The support unit 11 is for holding the spray means 12 and the stage 13 in a predetermined position so that the light emitter dispersion liquid is sprayed from a predetermined direction onto the light emitting element 53 held on the stage 13. It is a holding member. Below, an example of the specific structure of the support part 11 is demonstrated.

  The support unit 11 includes a base member 111, support members 112, 113, and 114, a moving mechanism 115, and a rotating mechanism 116. A moving mechanism 115 is provided in the vicinity of the center of the upper surface of the base member 111 in the x direction, and a rotating mechanism 116 is placed on the upper surface of the moving mechanism 115. A stage 13 is held on the upper surface of the rotation mechanism 116.

  Reference is now made to FIG. 2C. FIG. 2C is a schematic plan view showing the configuration of the substrate 51 on which a plurality of light emitting elements 53 are formed in a matrix. The substrate 51 is provided with a recess 131 for alignment. Further, a convex portion is provided on the upper surface of the stage 13, and the convex portion is fitted with the concave portion 131, whereby the substrate 51 is held at a predetermined position of the stage 13 in a predetermined direction. In general, the phosphor dispersion liquid is applied simultaneously to the plurality of light emitting elements 53 as described above, but hereinafter, in order to make the explanation easy to understand, the description will be given focusing on one light emitting element 53. In addition, since the emission angle of the phosphor dispersion liquid is wider than the size of the light emitting elements 53, even when a plurality of light emitting elements 53 are arranged, the same conditions (for example, phosphor dispersion) are used for each light emitting element 53. The phosphor dispersion liquid is applied at an incident angle and a coating amount of the liquid.

  The moving mechanism 115 moves the rotating mechanism 116 and the stage 13 placed on the upper surface along the y-axis direction. The rotation mechanism 116 is configured to be rotatable on the xy plane, and the rotation changes the orientation of the stage 13 held on the upper surface on the xy plane. The operations of the moving mechanism 115 and the rotating mechanism 116 are realized by driving means such as a motor, and the movement of the driving means (that is, the positions of the support members 113 and 114) is controlled by the position control unit 31.

  A pair of support members 112 are provided on the upper surface of the base member 111 so as to sandwich the stage 13 along the x direction. Further, the support member 113 is constructed and held by the pair of support members 112. A support member 114 is held by the support member 113 so as to be movable in the x direction along the support member 113. Further, the support member 114 holds the support member 117 so as to be movable in the z direction along the support member 114. The change of the positions of the support members 114 and 117 is realized by driving means such as a motor, and the movement of the driving means (that is, the positions of the support members 114 and 117) is controlled by the position control unit 31.

  A shaft member 124 is provided so as to extend from the support member 117 in the y direction. The spray member 12 is held on the shaft member 124 so as to be rotatable about the shaft member 124. Thereby, the orientation of the nozzle 121 is adjusted on the xz plane, and the phosphor dispersion liquid can be applied to the light emitting element 53 held on the stage 13 at a predetermined angle. The spray unit 12 may be fixed to the shaft member 124 in a predetermined direction, or a drive unit that rotates the spray unit 12 about the shaft member 124 may be provided. When the driving means is provided, the direction of the spray means 12 (that is, the operation of the driving means) may be controlled by the position control unit 31.

  As described above, by providing the support members 114 and 117 and the moving mechanism 115, the nozzle 121 is relatively translated with respect to the stage 13 along each of the x axis, the y axis, and the z axis. It becomes possible. In addition, by providing the rotation mechanism 116, the nozzle 121 can be rotated relative to the stage 13 about the normal direction (z axis). Further, since the spray means 12 is held rotatably on the xz plane around the shaft member 124, the rotation angle can adjust the incident angle of the phosphor dispersion liquid with respect to the light emitting element 53 on the stage 13. It becomes possible. In the following description, it is assumed that the rotation of the spray unit 12 is controlled by the position control unit 31.

  In the example of FIGS. 2A and 2B, the example in which the phosphor dispersion liquid in the tank 123 is pushed out by the pressure of air from the air supply unit 2 has been described, but a syringe-type tank 125 may be used as the tank 123. . For example, FIG. 2D is a schematic diagram illustrating an example in which a syringe type tank 125 is used. The syringe-type tank 125 includes a syringe 1251, a plunger 1252, a syringe / supply pipe connection unit 1253, and a syringe / nozzle connection unit 1254.

  The syringe / supply pipe connecting portion 1253 is provided in one of the syringes 1251 at the opening. By connecting the syringe 1251 and the air supply pipe 22 at the syringe / supply pipe connection portion 1253, the air supplied from the air supply pipe 22 flows into the syringe. A syringe / nozzle connection 1254 is provided at the other opening of the syringe 1251. A plunger 1252 is accommodated in the syringe 1251, and a coating liquid (that is, a phosphor dispersion liquid) is accommodated in a space between the plunger 1252 and the syringe / nozzle connection portion 1254.

  When air flows into the syringe 1251 from the syringe / supply pipe connecting portion 1253, the plunger 1252 is pushed out toward the syringe / nozzle connecting portion 1254 by the pressure of the air. At this time, the application liquid is pushed out of the syringe 1251 from the syringe / nozzle connection portion 1254 by the plunger 1252.

  Further, a liquid supply unit 122 ′ is provided on the nozzle 121 side instead of the pipe 122. By connecting a syringe / nozzle connection unit 1254 to the liquid supply unit 122 ′, the syringe type tank 125 is attached to the nozzle 121. With this configuration, the coating liquid pushed out of the syringe 1251 by the plunger 1252 is supplied into the nozzle 121 through the liquid supply unit 122 ′. Thus, by using the syringe-type tank 125, it is possible to reduce the liquid remaining on the inner wall of the tank by the plunger 1252, and for example, the liquid can be used without waste. In addition, since the liquid residue is reduced, it is possible to suppress fluctuations in the liquid concentration due to separation of liquid solids attached to the inner wall of the tank. Further, by providing the liquid supply part 122 ′, the syringe type tank 125 can be directly attached to the nozzle 121. Thereby, the distance between the nozzle 121 and the syringe-type tank 125 becomes short, and the maintainability concerning piping washing | cleaning improves.

  Note that a two-thread structure may be provided between the liquid supply unit 122 ′ and the syringe / nozzle connection unit 1254 so that the syringe-type tank 125 is detachable. With such a configuration, the supply of the coating liquid (that is, the phosphor dispersion liquid) can be easily performed by exchanging the syringe type tank 125 together. In the above description, the example in which the syringe type tank 125 is attached to the nozzle 121 via the liquid supply unit 122 ′ has been described. However, as in the above-described embodiment, the syringe type tank 125 is attached to the nozzle 121 via the pipe 122. May be connected.

(Method of applying phosphor dispersion)
Next, a method for applying the phosphor dispersion liquid will be described. In the light emitting device 50 according to the present embodiment, the wavelength conversion unit 55 is provided so as to cover the upper surface and the side surface of the light emitting element 53. Therefore, when forming the wavelength conversion unit 55, it is necessary to apply the phosphor dispersion liquid to both the upper surface and the side surface of the light emitting element 53. Therefore, the phosphor coating apparatus 1 according to the present embodiment adjusts the discharge direction of the phosphor dispersion liquid with respect to the light emitting element 53 on the stage 13 by adjusting the direction of the spray unit 12 with the shaft member 124 as an axis, The phosphor dispersion liquid is applied to both the upper surface and the side surface of the light emitting element 53. Hereinafter, this operation will be specifically described.

  First, refer to FIG. 3A. FIG. 3A is a schematic perspective view of the light emitting element 53. Hereinafter, as illustrated in FIG. 3A, a case where the light emitting element 53 has a plate shape having a rectangular upper surface 531 and side surfaces 532 a to 532 d provided around the upper surface 531 will be described as an example. Hereinafter, when the side surfaces 532a to 532d are not particularly distinguished, they are described as “side surfaces 532”.

  Reference is now made to FIGS. 3B and 3C. 3B and 3C are diagrams for explaining the positional relationship between the nozzle 121 and the light emitting element 53, and are schematic views of the nozzle 121 and the light emitting element 53 as seen from the y direction. L10 in FIGS. 3B and 3C indicates a discharge direction in which the phosphor dispersion liquid is discharged from the nozzle 121 on the xz plane. L11 indicates the normal direction of the upper surface 531 and corresponds to the z direction (vertical direction). L12 indicates the normal direction of the side surface 532, which corresponds to the y direction (horizontal direction). As shown in FIG. 3B, the angle α1 formed by the directions L10 and L11 indicates the incident angle of the phosphor dispersion liquid with respect to the upper surface 531. As shown in FIG. 3C, the angle α2 formed by the directions L10 and L12 indicates the incident angle of the phosphor dispersion liquid with respect to the side surface 532.

  The incident angles α1 and α2 of the phosphor dispersion liquid with respect to the upper surface 531 and the side surface 532 are determined by the rotation of the spray unit 12 around the shaft member 124, that is, the adjustment of the direction of the spray unit 12 on the xz plane. The adjustment of the orientation of the spray means 12 is controlled by the position control unit 31. Hereinafter, the inclination angle (orientation on the xz plane) of the nozzle 121 is indicated by an angle α1 shown in FIGS. 3B and 3C.

  As described above, the phosphor dispersion liquid is applied to both the upper surface 531 and the side surface 532 by adjusting the discharge direction L10 of the phosphor dispersion liquid so as to be obliquely incident on both the upper surface 531 and the side surface 532. It becomes possible. When the incident angle with respect to each surface of the upper surface 531 and the side surface 532 exceeds 70 [°], the phosphor dispersion liquid does not sufficiently adhere to the surfaces. Therefore, the control information for adjusting the inclination angle α1 of the nozzle 121 is generated so as to be adjusted within a range of 20 [°] ≦ α1 ≦ 70 [°]. The position control unit 31 controls the direction of the nozzle 121 based on this control information so that the inclination angle becomes α1. It is more preferable that the inclination angle α1 satisfies the condition of 45 [°] ≦ α1 ≦ 70 [°]. Specific conditions including the details of the inclination angle α1 of the nozzle 121 (that is, the discharge direction L10 of the phosphor dispersion liquid) will be described later as Example 1.

  When the inclination angle α1 of the nozzle 121 is adjusted, the position control unit 31 adjusts the relative direction of the nozzle 121 on the xy plane with respect to the stage 13 (that is, the light emitting element 53). A specific operation related to the adjustment of the orientation of the nozzle 121 will be described with reference to FIGS. 4A and 4B. 4A and 4B are diagrams for explaining a coating method in the present embodiment, and show a relative positional relationship between the light emitting element 53 and the nozzle 121 on the xy plane. FIG. 4A shows a case where the nozzle 121 is disposed so as to face the side surfaces 532a and 532b. FIG. 4B shows a case where the stage 13 is rotated 180 [deg.] On the xy plane from the state of FIG. 4A so that the nozzle 121 faces the side surfaces 532c and 532d.

  L20 in FIGS. 4A and 4B indicates a discharge direction in which the phosphor dispersion liquid is discharged from the nozzle 121 on the xy plane. 4A indicates a line obtained by extending the bisector of the angle formed by the side surfaces 532a and 532b toward the nozzle 121 side. An angle β indicates an angle formed by the discharge direction L20 and the bisector L21. When this angle β is | β |> 25 [°], the incident angle of the phosphor dispersion liquid exceeds 70 [°] with respect to any one of the side surfaces 532a and 532b, As a result, the phosphor dispersion liquid does not adhere sufficiently. Therefore, the control information for adjusting the angle β is generated so as to be adjusted within a range of −25 [°] ≦ β ≦ 25 [°]. Based on this control information, the position control unit 31 controls the direction of the nozzle 121 with respect to the light emitting element 53 so that the angle formed by the two adjacent side surfaces 532 is β. More preferably, the angle of incidence on both of the two side surfaces is controlled to be equal to β = 0 [°], that is, the direction of the bisector of the angle. The same applies to the case shown in FIG. 4B. That is, L21 in FIG. 4B indicates the bisector of the angle formed by the side surfaces 532c and 532d, and the angle β indicates the angle formed by the ejection direction L20 and the bisector L21. As in the case shown in FIG. 4A, the position control unit 31 determines that the angle formed by the two adjacent side surfaces 532 is β (−25 [°] ≦ β ≦ 25 [°]) based on the control information described above. Thus, the direction of the nozzle 121 with respect to the light emitting element 53 is controlled.

  As shown in FIGS. 4A and 4B, the discharge direction L20 of the phosphor dispersion liquid is adjusted so as to be incident obliquely with respect to both of two adjacent side surfaces (for example, the side surface 532a and the side surface 532b in FIG. 4A). Thus, the phosphor dispersion liquid can be applied to both of the two side surfaces. That is, by adjusting the inclination angle α1 and the angle β as described above, the nozzle 121 is disposed so as to face the upper surface 531 and the adjacent side surfaces (for example, the side surfaces 532a and 532b). Therefore, for example, as shown in FIG. 4A, after the light emitting element 53 and the nozzle 121 are arranged, the phosphor dispersion liquid is sprayed from the nozzle 121, so that fluorescence is applied to the three surfaces of the upper surface 531 and the side surfaces 532a and 532b. A body dispersion is applied. Thereafter, the rotation mechanism 116 is controlled, the stage 13 is rotated 180 [°], and the light emitting element 53 and the nozzle 121 are arranged as shown in FIG. 4B, whereby the upper surface 531 and the phosphor dispersion liquid are applied. It becomes possible to apply the phosphor dispersion liquid to the side surfaces 532c and 532d that are not formed. In such a configuration, the phosphor dispersion liquid is applied twice to the upper surface 531 while the phosphor dispersion liquid is applied once to each side surface. Therefore, in consideration of the difference in the number of times of application, the inclination angle α1 of the nozzle 121 may be adjusted so that the film thickness of each surface becomes a desired thickness.

  When spraying the phosphor dispersion liquid from the nozzle 121, it is preferable to move either the nozzle 121 or the stage 13 so that the nozzle 121 and the side surface 532 facing the nozzle approach each other. Specifically, in the case shown in FIG. 4A, the position controller 31 controls the movement of the support member 114 in the x direction so that the side surfaces 532a and 532b facing the nozzle approach the nozzle 121 along the y direction. Move to. By operating in this way, the speed at which the phosphor dispersion liquid collides with each surface of the light emitting element 53 is higher than when the support member 114 is not moved. Therefore, it is possible to improve the adhesion to the light emitting element 53 and the drying property of the phosphor dispersion liquid by using the impact at the time of the collision.

  Further, when applying the phosphor dispersion liquid, the discharge control unit 32 controls the opening and closing of the valve in the nozzle 121 via the air supply unit 23 by the air supply unit 2, and intermittently discharges the phosphor dispersion liquid from the nozzle 121. Spray. In this way, by applying the phosphor dispersion liquid to the light emitting element 53, the drying of the phosphor dispersion liquid applied immediately before is promoted using the period when the discharge of the phosphor dispersion liquid is stopped. Is possible. In other words, drying can be promoted by controlling the application timing of the phosphor dispersion liquid and air without heating the substrate for drying during spray coating. In addition, it becomes possible to make the drying property of the phosphor dispersion liquid higher as the period for stopping the discharge of the phosphor dispersion liquid is lengthened. Further, air may be output from the nozzle 121 during the period when the discharge of the phosphor dispersion liquid is stopped. By outputting air, drying of the phosphor dispersion liquid during the discharge stop period is further promoted, and the phosphor dispersion liquid remaining at the tip of the nozzle 121 is discharged. Thereby, the clogging of the nozzle 121 can be suppressed, and the stability of the application amount during intermittent application can be improved. Note that the discharge stop period and the air output period may be changed according to the viscosity of the phosphor dispersion liquid.

  Next, a flow of a series of processes relating to the application of the phosphor dispersion liquid will be described with reference to FIG. FIG. 5 is a flowchart showing a flow of a series of processes related to the application of the phosphor dispersion liquid.

(Step S11)
First, the light emitting element 53 (strictly, the substrate 51 on which the light emitting element 53 is installed), which is an object to be coated with the phosphor dispersion liquid, is installed on the stage 13.

(Step S12)
When the light emitting element 53 is installed on the stage 13, the position control unit 31 controls the operation of the support unit 11 based on control information stored in advance, and adjusts the inclination angle of the nozzle 121 to be α1. . In this control information, the inclination angle α1 of the nozzle 121 is adjusted within a range of 20 [°] ≦ α1 ≦ 70 [°] (more preferably, 45 [°] ≦ α1 ≦ 70 [°]). Has been generated.

(Step S13)
Reference is now made to FIG. 4A. When the inclination angle of the nozzle 121 is adjusted, the position control unit 31 controls the operation of the rotation mechanism 116 to rotate the stage 13 so that the nozzle 121 faces both the side surfaces 532a and 532b. The relative positional relationship between the nozzle 53 and the nozzle 121 is adjusted. In this control information, the angle β formed by the bisector L21 of the angle formed by the side surfaces 532a and 532b and the discharge direction L20 of the phosphor dispersion liquid is −25 [°] ≦ β ≦ 25 [°]. It is generated so as to be adjusted within a range (more preferably, β = 0 [°]). At this time, since the inclination angle of the nozzle 121 is adjusted to be α1, the nozzle 121 is disposed so as to face the three surfaces of the upper surface 531 and the side surfaces 532a and 532b.

(Step S14)
As shown in FIG. 4A, when the light emitting element 53 and the nozzle 121 are arranged, the discharge control unit 32 controls the operation of the air supply unit 2 at a timing based on control information stored in advance, and the phosphor 121 is dispersed from the nozzle 121. Spray liquid or air. The control information includes information indicating the timing of discharging the phosphor dispersion liquid and air from the nozzle 121, specifically, the time T1 for discharging the phosphor dispersion liquid, the time T2 for spraying air, and Information indicating a cycle T3 in which the discharge and stop of the phosphor dispersion liquid are repeated is included. The time T1 is 5 [ms] ≦ T1 ≦ 1000 [ms], the time T2 is 0 [ms] <T2 ≦ 1000 [ms], and the period T3 is 50 [ms] ≦ T3 ≦ 2000 [ms]. It is desirable to do.

(Step S15)
When the application of the phosphor dispersion liquid is not completed for all the side surfaces 532 (step 15, N), the position control unit 31 controls the operation of the rotation mechanism 116 so that the nozzle 121 is moved to the other side surface. The stage 13 is rotated so as to face 532. In this way, when the relative positional relationship between the nozzle 121 and the light emitting element 53 is changed, the ejection control unit 32 controls the operation of the air supply unit 2, and the phosphor dispersion liquid or air is discharged from the nozzle 121. To spray. By operating in this way, the phosphor dispersion liquid is applied to the upper surface 531 and all the side surfaces 532. When the phosphor dispersion liquid is applied to all the side surfaces 532 (step S15, Y), the phosphor coating apparatus 1 ends the series of operations.

Example 1
Next, as Example 1, the adhesion of the phosphor dispersion liquid to the upper surface 531 when the inclination angle α1 of the nozzle 121 was changed in the range of 20 [°] to 70 [°] was verified. In this verification, 8 × 50 light-emitting elements 53 having a vertical length of 250 μm, a horizontal size of 500 μm, and a thickness of 100 μm are arranged in an array at intervals of 300 μm, and these are arranged as an object to be coated. did. Moreover, AS-80-011 made from Anest Iwata was used for the spray nozzle. Further, the composition of the coated material is 150 g of YAG phosphor having an average particle diameter of 10 to 20 [μm] in the phosphor liquid, 4 g of hydrophilic smectite in the layered silicate mineral, and 5 g of RX300 in the inorganic fine particles. Used was a mixture of 100 g of isopropyl alcohol, 50 g of ethylene glycol, and 50 g of 1,4-butanediol. Moreover, what mixed polysiloxane and isopropyl alcohol in the ratio of 1: 6 is used for a ceramic precursor liquid. Further, as operating conditions of the phosphor coating apparatus 1, the atomizing pressure is 0.1 [Mpa], the coating liquid pressure is 0.01 [Mpa], the coating liquid discharge time is 50 [msec], and the air discharge time is 50 [mpa]. msec], the frequency at which the coating liquid was repeatedly discharged and stopped was 5 [Hz], and the relative movement speed of the nozzle 121 relative to the stage 13 during the coating liquid discharging period was 5 [mm / sec]. Further, as conditions for the coating environment, the air temperature was 25 ° C. and the humidity was 40%.

  Under the above conditions, the phosphor dispersion liquid was applied to the light emitting element 53, and the thickness of the phosphor dispersion liquid adhered to the upper surface 531 and the side surface 532 was measured. The verification result is shown in FIG. 6A. FIG. 6A shows the phosphor film thickness [μm on the upper surface 531 when the inclination angle α (that is, the incident angle α) [°] of the nozzle 121 is changed in the range of 20 [°] to 70 [°]. ] And the measured value showing the relationship between the thickness of the phosphor deposited on the side surface [μm].

  As shown in FIG. 6A, the larger the nozzle inclination angle α, the thinner the film thickness attached to the upper surface 531 and the thicker the film thickness attached to the side surface 532. In other words, the larger the incident angle on each surface (that is, the shallower the incident angle with respect to that surface), the thinner the deposited film thickness.

  Moreover, when the incident angle with respect to each surface of the upper surface 531 and the side surface 532 exceeds 70 [°], the phosphor dispersion liquid does not sufficiently adhere to the surfaces. Therefore, the position control unit 31 determines the inclination angle α1 of the nozzle 121 within a range of 20 [°] ≦ α1 ≦ 70 [°]. In addition, when the phosphor dispersion liquid is applied to all the side surfaces 532, the phosphor dispersion liquid is applied to the upper surface 531 a plurality of times. Therefore, it is desirable that more phosphor dispersion liquid is applied to the side surface 532 than the upper surface 531 in one application. Specifically, the inclination angle α1 is set to 20 [°] ≦ α1 ≦ 70 [°]. It is good to decide within the range. As described above, in this embodiment, the phosphor dispersion liquid is applied to the upper surface 531 twice while the phosphor dispersion liquid is applied once to each side surface 532. Therefore, when the phosphor dispersion liquid is applied almost uniformly to both the upper surface 531 and each side surface 532, the application is performed so that the film thickness of the side surface 532 is larger than the film thickness of the upper surface 531 in one application. Good. Specifically, the inclination angle α1 may be determined within a range of 45 [°] ≦ α1 ≦ 70 [°].

  Next, a specific composition of the coating liquid for forming the wavelength conversion unit 55 will be described below as an example. Specifically, Comparative Examples 1 to 3 and Examples 2-1 and 2-2 were generated as samples in which the composition of the solvent in the coating solution was changed, and “adhesion evaluation” was performed on each sample. Went. The solvent used was isopropyl alcohol as a low boiling point solvent, ethylene glycol as a medium boiling point solvent, and 1,4-butanediol as a high boiling point solvent. Comparative Example 1 shows an example of drying by heating the substrate when spraying the phosphor dispersion liquid as in the prior art. Further, Comparative Example 2, Comparative Example 3, Example 2-1, and Example 2-2 show cases where the phosphor dispersion liquid is applied without heating the substrate when spraying the phosphor dispersion liquid. Each shows the case where the composition ratio of the solvent in the liquid is changed. In addition, the comparative example 2 has shown the case where the composition ratio of the comparative example 1 and a solvent is made the same.

  The result of this evaluation is shown in FIG. 6B. FIG. 6B is a table showing the evaluation results of Comparative Examples 1 to 3, Example 2-1, and Example 2-2. The presence or absence of heating in FIG. 6B indicates whether or not heating of the substrate for drying is performed during spray coating of the phosphor dispersion liquid. In Comparative Examples 1 to 3, Example 2-1, and Example 2-2, the composition ratio of the solvent is changed. Specifically, a composition ratio of a low boiling point solvent having a boiling point of less than 100 [° C.], a medium boiling point solvent having a boiling point of 100 [° C.] or more and less than 200 [° C.], and a high boiling point solvent of 200 [° C.] or more. Is changed for each embodiment. Examples of the low boiling point solvent include methanol, ethanol, and isopropyl alcohol. Examples of the medium boiling point solvent include water, butanol, ethylene glycol, and propylene glycol. Examples of the high boiling point solvent include 1,3-butanediol, 1,4-butanediol, and glycerin. In addition, the numerical value of the solvent composition ratio in FIG. 6B shows the weight ratio.

(Adhesion evaluation)
In the adhesion evaluation, the wavelength conversion unit 55 is formed on the light emitting element 53 so that the film thickness of the upper surface 531 is 40 [μm] and the film thickness of the side surface 532 is 30 [μm] for each example. After that, the film thickness of the corner portion corresponding to the boundary between the upper surface 531 and the side surface 532 was measured, and it was “◯” in the range of 30 to 40 μm, and “x” in the other cases. That is, in this evaluation, it is evaluated whether the wavelength conversion unit 55 is formed with a uniform film thickness on each surface.

  Next, specific conditions of Comparative Examples 1 to 3, Example 2-1, and Example 2-2 and results of each evaluation are summarized below.

(Comparative Example 1)
Comparative Example 1 shows an example in which the phosphor dispersion liquid applied to the light emitting element 53 is dried by performing a substrate heat treatment during the application of the phosphor dispersion liquid as in the past. In Comparative Example 1, the solvent composition ratio was 60 for the high-boiling component relative to 30 for the low-boiling component. As for the solvent, generally, the higher the boiling point of the solvent, the higher the viscosity. In order not to precipitate the phosphor particles in the phosphor dispersion liquid, a predetermined viscosity is required. preferable. On the other hand, in order to atomize by the spray means 12, it is preferable to add a low boiling point solvent having relatively high volatility. When a phosphor dispersion liquid was generated using a solvent having this composition ratio and applied to the light emitting element 53, a substrate heat treatment was performed and the resultant was dried. As shown in FIG. 6B, the result of the adhesion evaluation of Comparative Example 1 was “◯”.

(Comparative Example 2)
Comparative Example 2 shows a case where a phosphor dispersion liquid is generated with the same solvent composition ratio as Comparative Example 1, and this is intermittently applied, but at that time, no substrate heating treatment is performed during the application. As shown in FIG. 6B, the result of the adhesion evaluation of Comparative Example 2 was “x”. A specific state of the sample according to Comparative Example 2 is shown in FIG. 6C. FIG. 6C shows an outline of a sample according to Comparative Example 2. As shown in FIG. 6C, the sample according to Comparative Example 2 cannot obtain sufficient drying properties, and a large amount of residual solvent remains in the coating film, so that a sufficient film thickness is secured at the corner portion by the surface tension. I couldn't.

(Comparative Example 3)
Comparative Example 3 shows a case where a phosphor dispersion liquid is generated using only a low boiling point solvent as a solvent, and this is dried by intermittent application, without performing heat treatment. As shown in FIG. 6B, the result of the adhesion evaluation was “x”. Specifically, in the case of the solvent composition ratio shown in Comparative Example 3, it is difficult to stabilize the coating amount because the phosphor particles are low in viscosity, and the result of the adhesion evaluation is “x”. Yes. Thus, when there are too many low boiling point components, the phosphor dispersion liquid has low storage stability in a dispersed state, and it is necessary to keep stirring constantly in order to apply this, and this embodiment relates to this embodiment. The composition of the solvent for producing the phosphor dispersion is not desirable.

(Example 2-1)
Next, Example 2-1 will be described. In this example, the low boiling point component was 60 and the high boiling point component was 40 as the solvent composition ratio. That is, in this example, the ratio of the low boiling point component is set higher than in Comparative Example 1 and Comparative Example 2. Using this solvent, a phosphor dispersion liquid was produced, and this was intermittently applied to the light emitting element 53, so that it was dried without being subjected to heat treatment, and subjected to evaluation. As shown in FIG. 6B, the result of the adhesion evaluation of this example was “◯”.

(Example 2-2)
Next, Example 2-2 will be described. In this example, based on the solvent composition ratio of Example 2-1, a part of the high boiling point solvent is replaced with a medium boiling point solvent. Specifically, the low boiling point component was 60, the medium boiling point component was 30, and the high boiling point component was 30. Using this solvent, a phosphor dispersion liquid was produced, and this was intermittently applied to the light emitting element 53, so that it was dried without being subjected to heat treatment, and subjected to evaluation. As shown in FIG. 6B, the result of the adhesion evaluation of this example was “◯” as in Example 2-1. In addition, although the solvent shown in Example 2-1 has improved drying property, there exists a problem that a viscosity changes with time. However, by adding a medium-boiling solvent as in this example, it is possible to reduce the change in viscosity over time as compared with the case of Example 2-1.

  As described above, as shown in Example 2-1 and Example 2-2, by increasing the component ratio of the solvent (alcohol) less than 100 [° C.] to the solvent (water or alcohol) of 100 [° C.] or higher. The drying property of the phosphor dispersion using this solvent can be improved. In addition, in Example 2-1 and Example 2-2, the amount of the solvent component less than 100 [° C.] (low boiling point) is M1, the amount of the solvent component of 100 [° C.] or more (medium boiling point and high boiling point) When M2, the condition of M2 ≦ M1 ≦ M2 × 2 is satisfied. By producing a phosphor dispersion using a solvent having such a composition ratio, it is possible to further improve the drying properties without causing the phosphor particles in the phosphor dispersion to settle. In addition, by using the phosphor dispersion liquid using such a solvent, it becomes possible to apply the phosphor dispersion liquid without heating the substrate during spray coating, so that volatilization of the solvent accompanying heating can be suppressed. It becomes possible, and strict explosion-proof measures are not required. In addition, since there is no need to perform heating, it is possible to suppress oxidation due to heating of metal parts such as the metal part 52 and the protruding electrode 54 during spray application.

As described above, the phosphor coating apparatus 1 according to the present embodiment uses the period in which the discharge of the phosphor dispersion liquid is stopped by intermittently applying the phosphor dispersion liquid to the light emitting element 53. It becomes possible to promote the drying of the phosphor dispersion liquid applied immediately before. Further, by selecting an appropriate solvent, it is possible to improve the drying property while maintaining the dispersion stability of the phosphor. The combination of both eliminates the need to heat the light emitting element 53 when spraying the phosphor dispersion.
In addition, the phosphor coating apparatus 1 according to the present embodiment tilts the nozzle 121 so as to face both the upper surface 531 and the side surface 532 with respect to the light emitting element 53 placed on the stage 13, and applies the phosphor dispersion liquid. Apply. By operating in this way, the phosphor dispersion liquid can be easily applied to both the upper surface 531 and the side surface 532. Further, by rotating the nozzle 121 relative to the stage 13, the phosphor dispersion liquid can be similarly applied to the other side surface 532. In addition, by appropriately adjusting the inclination angle α1 of the nozzle 121, it is possible to easily adjust the film thickness of the phosphor dispersion liquid applied to the upper surface 531 and the side surface 532.

(Modification)
Next, a method for applying the phosphor dispersion according to the modification will be described. In the above-described embodiment, the phosphor dispersion liquid is applied to three surfaces of the two side surfaces 532 adjacent to the upper surface 531, and then the stage 13 is rotated by 180 degrees to change the direction of the light emitting element 53 with respect to the nozzle 121. Thus, the phosphor dispersion liquid was applied to the other two side surfaces 532. In other words, the phosphor dispersion liquid is applied to all the side surfaces 532 by applying the phosphor dispersion liquid in two portions while changing the direction of the light emitting element 53 by 180 [°] on the xy plane. Was. In the method of applying the phosphor dispersion liquid according to the modification, the light emitting element 53 is divided into four times while changing the direction of the light emitting element 53 by 90 [°] on the xy plane for each application of the phosphor dispersion liquid. The phosphor dispersion is applied to Hereinafter, a method for applying the phosphor dispersion according to the modification will be described with reference to FIGS. 7A and 7B. FIG. 7A and FIG. 7B are diagrams for explaining a coating method in the modification, and show a relative positional relationship between the light emitting element 53 and the nozzle 121 on the xy plane. FIG. 7A shows a case where the nozzle 121 is disposed so as to face the side surfaces 532a and 532b. FIG. 7B shows a case where the stage 13 is rotated 90 [deg.] On the xy plane from the state of FIG. 7A so that the nozzle 121 faces the side surfaces 532b and 532c.

  L21 in FIGS. 7A and 7B indicates a discharge direction in which the phosphor dispersion liquid is discharged from the nozzle 121 on the xy plane. In the phosphor dispersion application method according to the modification, first, the position controller 31 controls the stage 13 so that the nozzle 121 faces the side surfaces 532a and 532b, as shown in FIG. 7A. Thereafter, the discharge control unit 32 controls the air supply unit 2 to apply the phosphor dispersion liquid to the three surfaces of the upper surface 531 and the side surfaces 532a and 532b. When the application of the phosphor dispersion liquid to the three surfaces is completed, the position control unit 31 rotates the stage 13 by 90 [°] so that the nozzle 121 faces the side surfaces 532b and 532c, as shown in FIG. 7B. When the stage 13 is rotated 90 [°], the discharge control unit 32 controls the air supply unit 2 to apply the phosphor dispersion liquid to the three surfaces of the upper surface 531 and the side surfaces 532b and 532c. Thereafter, in the same manner, the phosphor 13 is applied to the upper surface 531 and the two adjacent side surfaces 532 while rotating the stage 13 by 90 [°], so that the fluorescence is applied to all the side surfaces 532 in four steps. Apply body dispersion.

  Reference is now made to FIGS. 8A and 8B. 8A and 8B are schematic views of the phosphor dispersion liquid (that is, the wavelength converter 55) applied to the upper surface 531 in the above-described embodiment, as viewed from the y direction. 8A and 8B show a state before the direction of the light emitting element 53 is changed and a state after the direction of the light emitting element 53 is changed by rotating the stage 13 by 180 [°]. L31 in FIG. 7A indicates the discharge direction of the phosphor dispersion liquid before the direction of the light emitting element 53 is changed. When the wavelength conversion unit 55 is formed by intermittently applying the phosphor dispersion liquid, the wavelength conversion unit 55a is first formed by the first ejection. Thereafter, when the phosphor dispersion liquid is discharged next time, depending on the viscosity of the phosphor dispersion liquid and the discharge conditions, the previously formed wavelength conversion unit 55a may be one of the phosphor dispersion liquids to be discharged next. The wavelength converting part 55b is formed while shielding the part. Therefore, as shown in FIG. 8A, a concave portion is formed between the wavelength conversion portions 55a and 55b, and the wavelength conversion portion 55 having irregularities along the y direction may be formed by repeating this.

  The same applies to the case shown in FIG. 8B. L32 in FIG. 8B indicates the discharge direction of the phosphor dispersion liquid after the stage 13 is rotated by 180 [°]. As shown in FIG. 8B, for example, when the phosphor dispersion liquid is applied to the wavelength conversion section 55b, a part of the phosphor dispersion liquid is blocked by the wavelength conversion section 55c. Therefore, the unevenness along the y direction of the wavelength converter 55 is more emphasized.

  Reference is now made to FIG. 9A. FIG. 9A is a schematic view of the state shown in FIG. 8A viewed from the z direction. L31 in FIG. 9A indicates the discharge direction of the phosphor dispersion liquid, and corresponds to the discharge direction L31 in FIG. 8A. Moreover, the wavelength conversion parts 55a and 55b have shown a part of the wavelength conversion part 55 formed by intermittent discharge of a fluorescent substance dispersion liquid, and are formed in order of the wavelength conversion parts 55a and 55b.

  In the above-described embodiment, after the phosphor dispersion liquid is applied to the upper surface 531 facing the nozzle 121 and the two adjacent side surfaces 532, the light emitting element 53 is rotated by 180 [°], so that the nozzle 121 has the other two side surfaces. It arrange | positions so that 532 may face. However, in such a case, as in the state shown in FIG. 9A, the phosphor dispersion liquid is applied perpendicularly to the grooves formed by the wavelength converters 55a and 55b. Therefore, the unevenness due to the wavelength conversion units 55a and 55b is further emphasized.

  On the other hand, in the method for applying the phosphor dispersion according to the modification, the phosphor dispersion is applied while rotating the stage 13 by 90 [°]. FIG. 9B shows a state after the direction of the light emitting element 53 with respect to the nozzle 121 is changed by rotating the light emitting element 53 by 90 [°] on the xy plane from the state shown in FIG. 9A. By adjusting the positional relationship between the nozzle 121 and the light emitting element 53 in this manner, as shown in FIG. 9B, the nozzle 121 causes the phosphor dispersion liquid to flow along the grooves formed by the wavelength conversion units 55a and 55b. It becomes possible to apply. Thereby, even when irregularities as shown in the wavelength conversion portions 55a and 55b are formed by intermittent application of the phosphor dispersion liquid, the phosphor dispersion liquid can be applied so as to fill the irregularities.

  As described above, in the method of applying the phosphor dispersion liquid according to the modification, the phosphor dispersion liquid is applied to the upper surface 531 and the two side surfaces 532 adjacent to each other while rotating the stage 13 by 90 [°]. The phosphor dispersion liquid is applied to all the side surfaces 532 in four steps. Thereby, even when irregularities as shown in the wavelength conversion parts 55a and 55b are formed by intermittent application of the phosphor dispersion liquid, the nozzle 121 is then moved along the grooves formed by the wavelength conversion parts 55a and 55b. The phosphor dispersion liquid can be applied so as to fill the irregularities, and as a result, a coating film having high surface flatness can be formed.

  In addition, to repeat, in the case of a one-part formulation in which the phosphor dispersion liquid and the ceramic precursor liquid are mixed in advance, the phosphor dispersion liquid is applied in a predetermined amount as described above, and then dried and fired to obtain a predetermined amount. A film thickness wavelength conversion unit 55 is formed. In the case of a two-component formulation, the phosphor dispersion liquid not mixed with the ceramic precursor liquid is applied and dried in a predetermined amount as described above, and then the ceramic precursor liquid is applied, dried and baked to obtain a predetermined film thickness. The wavelength converter 55 is formed.

DESCRIPTION OF SYMBOLS 1 Phosphor coating apparatus 11 Support part 111 Base member 112, 113, 114, 117 Support member 115 Movement mechanism 116 Rotation mechanism 12 Spray means 121 Nozzle 122 Piping 122 'Liquid supply part 123 Tank 124 Shaft member 125 Syringe type tank 1251 Syringe 1252 Plunger 1253 Syringe / supply pipe connection part 1254 Syringe / nozzle connection part 13 Stage 131 Recess 21 Air supply pipe 22 Air supply pipe 23 Air supply pipe 31 Position control part 32 Discharge control part 2 Air supply part 3 Control part 50 Light emitting device 51 Substrate 52 Metal part 53 Light emitting element 54 Projection electrode 55 Wavelength conversion part

Claims (15)

A light-emitting device manufacturing method comprising: a light-emitting element that emits light of a predetermined wavelength; and a wavelength conversion unit that receives light emitted from the light-emitting element and emits fluorescence having a wavelength different from the predetermined wavelength. ,
A step of applying the phosphor dispersion liquid containing phosphor, inorganic fine particles, suspending agent, and solvent onto the light emitting element by spraying intermittently toward the light emitting element, and forming the wavelength conversion unit A method of manufacturing a light emitting device, comprising the step of:   The method for manufacturing a light emitting device according to claim 1, wherein the solvent includes water, alcohol, or a combination thereof.   The said solvent contains the 1st solvent comprised including the alcohol whose boiling point is less than 100 degreeC, and the 2nd solvent comprised including the water or alcohol whose boiling point is 100 degreeC or more, It is characterized by the above-mentioned. The manufacturing method of the light-emitting device of Claim 2.   4. The method of manufacturing a light emitting device according to claim 3, wherein the component weight M1 of the first solvent and the component weight M2 of the second solvent satisfy a condition of M2 ≦ M1 ≦ M2 × 2.   The method for manufacturing a light emitting device according to claim 1, wherein the precipitation inhibitor includes a layered silicate mineral.   6. The process according to claim 1, further comprising: applying a ceramic precursor liquid containing an organometallic compound on the light emitting element after applying the phosphor dispersion liquid. The manufacturing method of the light-emitting device as described in one.   In the step, the discharge of the phosphor dispersion liquid and the stop thereof are repeated to spray intermittently, and the discharge time T1 satisfies the condition of 5 [ms] ≦ T1 ≦ 1000 [ms]. The method for manufacturing a light emitting device according to claim 1, wherein:   During the period when the discharge of the phosphor dispersion liquid is stopped, air is sprayed on the light emitting element in a range of time T2 that satisfies a condition of 0 [ms] <T2 ≦ 1000 [ms]. A method for manufacturing a light emitting device according to claim 7.   9. The method for manufacturing a light emitting device according to claim 7, wherein the period T <b> 3 for repeating the discharge and the stop satisfies 50 [ms] ≦ T3 ≦ 2000 [ms]. The light emitting element is formed in a plate shape having an upper surface and a side surface,
2. In the step, the phosphor dispersion liquid is ejected in a direction inclined by a predetermined angle θ1 with respect to a normal direction of the upper surface, and is applied onto the light emitting element. The manufacturing method of the light-emitting device as described in any one of Claims 9-9.   The method for manufacturing a light emitting device according to claim 10, wherein the angle θ1 satisfies a condition of 20 ° ≦ θ1 ≦ 70 °.   The method for manufacturing a light-emitting device according to claim 10, wherein the angle θ1 satisfies a condition of 45 ° ≦ θ1 ≦ 70 °. The light emitting element has a quadrangular shape on the top surface and four side surfaces around the top surface,
In the step, an angle θ2 formed on a plane perpendicular to the normal direction is a direction in which the phosphor dispersion liquid is discharged and a direction in which a bisector of an angle formed by two adjacent side surfaces is extended. The phosphor dispersion liquid is applied to the upper surface and the two side surfaces by spraying while satisfying a condition of −25 ° ≦ θ2 ≦ 25 °. The manufacturing method of the light-emitting device as described in any one.   After the phosphor dispersion liquid is applied to the upper surface and the two side surfaces, the direction of the light emitting element is rotated by 180 ° about the normal line direction of the upper surface, and is positioned on the opposite side to the two side surfaces. The method for manufacturing a light emitting device according to claim 13, wherein the phosphor dispersion liquid is applied to the other two side surfaces and the upper surface.   After the phosphor dispersion liquid is applied to the upper surface and the two side surfaces, the direction of the light emitting element is rotated by 90 ° about the normal direction of the upper surface, which is different from the set of the two side surfaces. The method for manufacturing a light emitting device according to claim 13, wherein the phosphor dispersion liquid is applied to the pair of the two side surfaces and the upper surface.

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