JP6079025B2 - Silver discoloration preventing material, silver discoloration preventing film forming method, light emitting device manufacturing method, and light emitting device - Google Patents

Description

  The present invention relates to a silver discoloration preventing material, and more particularly to a silver discoloration preventing material for preventing discoloration due to sulfuration of silver plating used in a light emitting device or the like. The present invention also relates to a method for forming a silver discoloration preventing film using a silver discoloration preventing material and a method for manufacturing a light emitting device.

  In recent years, the demand for light-emitting diodes (LEDs) as a light source that replaces fluorescent lamps and incandescent lamps is rapidly increasing. A light-emitting device including a light-emitting element such as a light-emitting diode is used in applications such as lighting equipment and automobile lights. In such a light-emitting device, light extraction efficiency is improved by providing a light reflection film made of silver plating. For example, in an LED package including a lead frame such as a copper plating substrate, the reflectance is improved by providing a silver plating layer on the copper plating layer (see, for example, Patent Document 1 below).

JP 2009-239116 A

  In the LED package, the light emitting element, the light reflection film, and the like are usually protected by sealing with a transparent resin. However, when the light emitting device is used outdoors, there is a problem that the light reflectance is lowered due to the discoloration of the silver plating and the light emission luminance is lowered.

  Silver is easily discolored due to environmental factors such as temperature, humidity, and gas, and is one of the causes of LED package luminance fluctuation. In order to be used as a stable light source for a long period of time, it has been desired to solve the above problems.

  The present invention has been made in view of the above circumstances, and a silver discoloration prevention film capable of sufficiently suppressing silver discoloration, a method for forming a silver discoloration prevention film using the same, and light emission excellent in silver discoloration prevention properties An object is to provide an apparatus and a method for manufacturing the same.

  In order to solve the above problems, the present inventors have studied in detail the cause of the discoloration of the silver plating, and as a result, the silver plating is sulfided or the influence of impurity ions existing in the vicinity of the silver plating is the main. I found out. In particular, it has also been found that when there are impurity ions present in the vicinity of silver plating, discoloration tends to become more prominent under a high temperature and high humidity environment. The present inventors presume that the discoloration due to impurity ions is caused by migration of impurity ions. And as a result of further diligent examination based on this knowledge, the present inventors applied silver sulfiding and high-temperature, high-humidity environments by applying a material containing clay and an ion exchanger on the silver plating layer. The present inventors have found that a film capable of sufficiently suppressing both the silver discoloration and the present invention has been completed.

  That is, this invention provides the silver discoloration prevention material containing a clay and an ion exchanger.

  According to the silver discoloration preventing material of the present invention, it is possible to sufficiently suppress silver sulfidation and silver discoloration in a high-temperature and high-humidity environment by applying and drying on the surface of a metal layer containing silver. A possible silver discoloration preventing film can be formed.

  The mass ratio of clay to ion exchanger should be 95/5 to 70/30 from the viewpoint of achieving both the suppression of silver sulfidation and the suppression of silver discoloration in a high temperature and high humidity environment at a high level. preferable.

  The silver discoloration preventive material of the present invention has the following ion exchangers: (a) a zirconia ion exchanger, and (b) an antimony ion exchange, from the viewpoint of highly suppressing silver discoloration in a high temperature and high humidity environment. And (c) one or more ion exchangers selected from hydrotalcite-based ion exchangers.

  The present invention also includes a coating step of forming a silver discoloration prevention material coating on the surface of a silver-containing metal layer by applying the silver discoloration prevention material according to the present invention, and a drying step of drying the coating. A method for forming a silver discoloration prevention film comprising:

  According to the method for forming a silver discoloration prevention film of the present invention, by using the silver discoloration prevention material according to the present invention, silver capable of sufficiently suppressing silver sulfidation and silver discoloration in an environment of high temperature and high humidity. A discoloration preventing film can be formed.

  The metal layer is preferably a silver plating layer. In this case, discoloration of the silver plating layer due to sulfuration and discoloration of the silver plating layer in an environment of high temperature and high humidity can be suppressed, and the light reflectance of the silver plating layer can be prevented from decreasing. .

  The present invention is also a method for producing a light emitting device comprising a substrate having a silver plating layer and a light emitting element mounted on the substrate, wherein the silver discoloration prevention material according to the present invention is formed on the surface of the silver plating layer. The manufacturing method of a light-emitting device provided with the application | coating process which forms a coating film of silver discoloration prevention material by apply | coating, and the drying process which dries a coating film is provided.

  According to the method for manufacturing a light-emitting device of the present invention, silver that can sufficiently suppress silver sulfidation on the surface of the silver plating layer and that can sufficiently suppress discoloration of silver in a high-temperature and high-humidity environment. A discoloration-preventing film can be formed, and as a result, a light emitting device excellent in silver discoloration-preventing property can be produced in which the silver plating layer is difficult to discolor.

  In addition, according to the method for manufacturing a light emitting device of the present invention, a silver discoloration preventing film having excellent adhesion can be formed by using the silver discoloration preventing material according to the present invention. Further, it is possible to sufficiently suppress a decrease in reflectance due to film peeling caused by heat shrinkage during lighting on / off.

  Furthermore, according to the method for manufacturing a light emitting device of the present invention, it is possible to form a silver discoloration-preventing film that is difficult to generate a crack even with a thick film by using the silver discoloration preventing material according to the present invention. A light-emitting device having a high level of sulfidation resistance can be manufactured while sufficiently suppressing manufacturing problems caused by the problem.

  The present invention also includes a substrate having a silver plating layer, a light emitting element mounted on the substrate, and a silver discoloration prevention film provided on the surface of the silver plating layer, and the silver discoloration prevention film is ion-exchanged with clay. A light-emitting device containing the body is provided.

  The light-emitting device of the present invention has excellent silver discoloration prevention properties by including the silver discoloration prevention film, and the silver plating layer is difficult to discolor.

  The mass ratio of clay to ion exchanger in the silver discoloration-preventing film is 95/5 to 70 from the viewpoint of achieving both the suppression of silver sulfidation and the suppression of discoloration of silver in a high temperature and high humidity environment at a high level. / 30 is preferable.

  From the viewpoint of highly suppressing silver discoloration in a high-temperature, high-humidity environment, the above-mentioned silver discoloration prevention film is used as an ion exchanger (a) a zirconia-based ion exchanger, (b) an antimony-based ion exchanger, and ( c) It is preferable to include one or more ion exchangers selected from hydrotalcite ion exchangers.

  ADVANTAGE OF THE INVENTION According to this invention, the silver discoloration prevention material which can fully suppress silver sulfide, and can also fully suppress the discoloration of silver in a high temperature and high humidity environment, and a silver discoloration prevention film using the same Can be provided, and a light emitting device excellent in silver discoloration prevention property and a method for producing the same.

It is sectional drawing of a light-emitting device. It is a top view of the light-emitting device shown in FIG. 3 is a flowchart illustrating a method for manufacturing the light emitting device according to the first embodiment. It is sectional drawing of the light-emitting device after the application | coating process of the silver discoloration prevention material which concerns on embodiment. It is sectional drawing of the light-emitting device after a drying process. It is sectional drawing of the light-emitting device after a transparent sealing resin filling process. It is a conceptual diagram for demonstrating the structure of the silver discoloration prevention film formed from the silver discoloration prevention material which concerns on embodiment. It is the flowchart which showed the manufacturing method of the light-emitting device which concerns on 2nd Embodiment. It is sectional drawing of the light-emitting device manufactured with the manufacturing method of FIG. It is the flowchart which showed the manufacturing method of the light-emitting device which concerns on 3rd Embodiment. It is sectional drawing of the light-emitting device manufactured with the manufacturing method of FIG.

  The silver discoloration preventing material according to this embodiment includes clay and an ion exchanger. This silver discoloration preventing material can contain a solvent for dispersing clay and ion exchangers. According to the silver discoloration preventing material of the present embodiment, a silver discoloration preventing film capable of sufficiently suppressing silver sulfidation can be formed by applying to the surface of the metal layer containing silver and drying. Examples of the metal layer include a silver plating layer and a silver paste layer.

  As the clay, natural clay, synthetic clay, and one of these modified materials can be used alone or in combination of two or more.

  As natural clay, the following layered silicates can be used, for example. Specific examples include kaolin, talc-pyrophyllite, smectite, vermiculite, mica (mica), brittle mica, and chlorite. Typical species include lizardite, amicite, chrysotile, kaolinite, dickite, halloysite, talc, pyrophyllite, saponite, hectorite, montmorillonite, beidellite, trioctahedral vermiculite, octahedral vermiculite, phlogopite. , Biotite, lepidrite, illite, muscovite, paragonite, clintonite, margarite, clinochlore, chamosite, nimite, dombasite, kukeite, sudite. Examples of commercially available products include Kunipia (Kunimine Kogyo Co., Ltd., trade name, Kunipia F), and wet pulverized mica (Yamaguchi Mica, Y series, SA series).

  Examples of the synthetic clay include fluorine phlogopite, potassium tetrasilicon mica, sodium tetrasilicon mica, Na teniolite, Li teniolite, montmorillonite, saponite, hectorite, and stevensite. Commercially available products include Micromica, Somasifu (Coop Chemical Co., Ltd., trade name, MEB-3), Lucentite (Coop Chemical Co., Ltd., trade name, SWN), Swellable Micasol (Topy Industries, NTS) -10, NTS-5).

  As a modified product of synthetic clay, for example, Somasifu (manufactured by Co-op Chemical Co., Ltd., trade name, MAE) and Lucentite (manufactured by Co-op Chemical Co., Ltd., trade name, SPN) are listed as commercial products.

  In this embodiment, it is preferable to contain montmorillonite as clay from a viewpoint of improving the silver discoloration prevention property of the silver discoloration prevention film to be formed. The montmorillonite preferably has a shape with a thickness of 1 nm or less and a length in the diameter direction of 10 nm or more and 400 nm or less, and more preferably has an aspect ratio of 10 or more. The aspect ratio here means the average long side length / average thickness of the crystal.

  Examples of the ion exchanger include (a) zirconia ion exchangers, (b) antimony ion exchangers, and (c) hydrotalcite ion exchangers. From the viewpoint of preventing silver discoloration (discoloration caused by invasion of moisture and migration of silver due to residual ions) in a high-temperature, high-humidity environment, the silver discoloration prevention material according to this embodiment is described above. It is preferable to include one or more ion exchangers selected from ion exchangers.

  Examples of (a) zirconia ion exchangers include zirconium salts represented by zirconium hydroxide and zirconium phosphate. Moreover, IXE100 (made by Toagosei Chemical Co., Ltd., a brand name) etc. are mentioned as a zirconia-type ion exchanger marketed.

  Examples of (b) antimony ion exchangers include antimonates such as antimonic acid and antimony phosphate. Moreover, IXE300 (made by Toagosei Chemical Co., Ltd., a brand name) etc. are mentioned as a commercially available antimony type ion exchanger.

(A) A zirconia ion exchanger and (b) an antimony ion exchanger interact with sodium ion (Na ⁺ ), lithium ion (Li ⁺ ), potassium ion (K ⁺ ) and the like with an electronegative chemical structure. Adsorbs by action, or has a substitution action with hydrogen ions (H ⁺ ). If sodium ions (Na ⁺ ), lithium ions (Li ⁺ ), potassium ions (K ⁺ ), etc. are present in the silver discoloration prevention film, it is considered that discoloration due to the occurrence of silver migration occurs, and the above ion exchange It is considered that the discoloration of silver can be sufficiently suppressed by immobilizing ions by the action of the body.

(C) As a hydrotalcite type ion exchanger, the double hydroxide represented by following General formula (1) is mentioned, for example.
M ¹ _8-x M ² _x (OH) ₁₆ CO ₃ .nH ₂ O (1)
In formula (1), M ¹ represents Mg ²⁺ , Fe ²⁺ , Zn ²⁺ , Ca ²⁺ , Li ²⁺ , Ni ²⁺ , Co ²⁺ , or Cu ²⁺ , and M ² represents Al ³⁺ , Fe ³⁺ , Mn ³⁺ . X represents an integer of 2 to 5, and n represents a positive integer.

Among these, a magnesium and aluminum compound represented by the following chemical composition formula is particularly preferable.
Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O
Such a compound is commercially available as HT-P (trade name, manufactured by Sakai Chemical Co., Ltd.).

  (C) In addition to the above HT-P, for example, DHT-4A-2, KW2200, and the like are commercially available from Kyowa Chemical Co., Ltd. as the hydrotalcite-based ion exchanger.

Hydrotalcite has a function of dissociating carbonate groups to generate carbonate ions (CO ₃ ²⁻ ), and replacing the carbonate ions with chloride ions (Cl ⁻ ), sulfate ions (SO ⁴⁻ ) and the like. ing. If chloride ions (Cl ⁻ ), sulfate ions (SO ⁴⁻ ), etc. are present in the silver discoloration prevention film, it is considered that discoloration occurs due to the occurrence of silver migration. It is considered that the discoloration of silver can be sufficiently suppressed by fixing.

  When one or more of (a) a zirconia ion exchanger and (b) an antimony ion exchanger are used in combination with one or more of (c) a hydrotalcite ion exchanger, halogen ions and alkalis are used. Metal ions and the like can be reduced.

  In this embodiment, ion exchangers other than those described above can be used. Examples include bismuth ion exchangers, antimony / bismuth ion exchangers, and zirconium / bismuth ion exchangers. Commercially available products can be used as these ion exchangers. Specific examples include IXE500 and IXE550 as bismuth ion exchangers, IXE600 and IXE633 as antimony and bismuth ion exchangers, zirconium -IXE6107 (above, Toagosei Chemical Co., Ltd. product name) etc. are mentioned as a bismuth-type ion exchanger.

  The silver discoloration prevention material of the present embodiment has a mass ratio of clay to ion exchanger from the viewpoint of further reducing halogen ions, alkali metal ions, etc. resulting from the environment or remaining in the material in the silver discoloration prevention film to be formed. It is preferably 70/30 to 95/5. Further, from the viewpoint of achieving a high level of silver discoloration and silver sulfide prevention in a high temperature and high humidity environment, the mass ratio of clay to ion exchanger is preferably 70/30 to 90/10. 80/20 to 90/10 is more preferable.

  From the viewpoint of improving the silver discoloration prevention performance of the silver discoloration prevention film, the silver discoloration prevention material of the present embodiment has a total content of clay and ion exchanger of 5% by mass or more based on the total solid content of the silver discoloration prevention material. It is preferably 10% by mass or more, and particularly preferably 80% by mass or more.

  The mass of the solid content of the silver discoloration preventing material means a value measured as follows. The silver discoloration-preventing material is placed on an aluminum dish and the mass after drying at 150 ° C. for 2 hours is measured.

In addition, about the solid content density | concentration of a silver discoloration prevention material, a silver discoloration prevention material is taken to an aluminum dish, the mass is measured, and it calculates | requires according to the following formula from the value which measured the mass after drying for 2 hours at 150 degreeC after that. be able to.
Solid content concentration = (mass after drying) / (mass before drying) × 100

  The concentration of clay in the silver discoloration preventing material of the present embodiment is 0.01% by mass or more and 50% by mass or less based on the total amount of the silver discoloration preventing material from the viewpoint of improving the silver discoloration preventing performance of the silver discoloration preventing film. Is preferable, 0.05 mass% or more and 10 mass% or less is more preferable, and 0.1 mass% or more and 5 mass% or less is further more preferable.

  In addition, the silver discoloration prevention material of this embodiment is one in which clay and an ion exchanger are contained in separate liquid compositions, respectively, and these may be mixed in use. That is, the silver discoloration preventing material of this embodiment may be one liquid or two liquids or more.

  Examples of the solvent include water and a water-soluble liquid.

  As water, for example, ultrapure water is used. Ultrapure water is water that contains a very small amount of ionic impurities, and has an electrical resistivity (specific resistance, MΩ · cm) (JIS K0552) as an index, and has a theoretical value of 15 MΩ · cm or more at 25 ° C., Preferably, water of 18 MΩ · cm or more can be used.

  Examples of the water-soluble liquid include polar solvents such as alcohol, specifically, ethanol, methanol, isopropyl alcohol, n-propyl alcohol, dioxane, acetone, acetonitrile, diethylamine, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, pyridine, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, propylene carbonate, γ-butyrolactone, formamide, allyl alcohol, acrylic acid, acetic acid, ethylene glycol, propylene glycol, glycerin, methacryl Liquids such as acid, butyric acid, trimethylamine, triethylamine, ammonia, and diethyl sulfite can be employed. A water-soluble liquid refers to a liquid that maintains a uniform appearance even after the flow has subsided when gently mixed with pure water of the same volume at a temperature of 20 ° C. at 1 atm. A water-soluble liquid can be used individually by 1 type or in mixture of 2 or more types.

  In this embodiment, it is preferable to contain water and a water-soluble liquid as a solvent. From the viewpoint of improving the silver discoloration prevention property by forming a uniform silver discoloration prevention film, the mass ratio of water to the water-soluble liquid is preferably 99/1 to 50/50, and 95/5 to 60 / 40 is more preferable, and 90/10 to 70/30 is even more preferable.

  Various additives can be added to the silver discoloration preventing material of the present embodiment as long as the effects of the present invention are not impaired. Examples of the additive include a binder and a surfactant.

  Examples of the method for preparing the silver discoloration preventing material of the present embodiment include a method in which clay, an ion exchanger, and, if necessary, the above additives are added to a solvent containing water and dispersed and stirred. Stirring can be performed using, for example, a rotation / revolution mixer, a stirrer, ultrasonic waves, a shaker, or the like.

  According to the silver discoloration prevention material of this embodiment, silver discoloration prevention that can sufficiently suppress the sulfuration and discoloration of silver on the surface of the metal layer by applying and drying on the surface of the metal layer containing silver. A film can be formed.

  Next, a preferred embodiment of a method for forming a silver discoloration prevention film using the silver discoloration prevention material of the present embodiment and a method for manufacturing a light emitting element will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[First Embodiment]
First, before explaining the manufacturing method of the light emitting device according to the first embodiment, the configuration of the light emitting device manufactured by the manufacturing method of the light emitting device according to the first embodiment with reference to FIG. 1 and FIG. Will be described.

  FIG. 1 is a cross-sectional view of the light emitting device. FIG. 2 is a plan view of the light-emitting device shown in FIG. As shown in FIGS. 1 and 2, the light emitting device 1 according to the embodiment is generally classified as a “surface mount type”. The light emitting device 1 includes a substrate 10, a blue LED 30 bonded to the surface of the substrate 10 as a light emitting element, a reflector 20 provided on the surface of the substrate 10 so as to surround the blue LED 30, and the reflector 20 filled with blue. And a transparent sealing resin 40 that seals the LED 30. In addition, illustration of the transparent sealing resin 40 is abbreviate | omitted in FIG.

  In the substrate 10, a copper plating plate 14 is wired on the surface of an insulating base 12, and a silver plating layer 16 is formed on the surface of the copper plating plate 14. The silver plating layer 16 is an electrode that is disposed on the surface of the substrate 10 and is electrically connected to the blue LED 30. The silver plating layer 16 may have any composition as long as it is a plating layer containing silver. For example, the silver plating layer 16 may be formed by plating only silver, or the silver plating layer 16 may be formed by plating nickel and silver in this order. The copper plating plate 14 and the silver plating layer 16 are insulated on the anode side and the cathode side. The insulation between the copper plating plate 14 and the silver plating layer 16 on the anode side and the copper plating plate 14 and the silver plating layer 16 on the cathode side is, for example, the copper plating plate 14 and the silver plating layer 16 on the anode side and the cathode side. The copper plating plate 14 and the silver plating layer 16 can be separated from each other, and an insulating layer such as a resin and ceramic can be appropriately inserted between them.

  The blue LED 30 is die-bonded to any one of the silver plating layer 16 on the anode side and the cathode side, and is electrically connected to the silver plating layer 16 through the die bonding material 32. The blue LED 30 is wire-bonded to the silver plating layer 16 on either the anode side or the cathode side, and is electrically connected to the silver plating layer 16 via the bonding wire 34.

  The reflector 20 fills a transparent sealing resin 40 for sealing the blue LED 30 and reflects light emitted from the blue LED 30 to the surface side of the light emitting device 1. The reflector 20 is erected from the surface of the substrate 10 so as to surround the blue LED 30. That is, the reflector 20 is formed with an inner space 22 that rises from the surface 10a of the substrate 10 so as to surround the blue LED 30 and accommodates the blue LED 30 inside, and has an inner circumference formed in a circle in plan view (see FIG. 2). A surface 20a, a top surface 20b adjacent to the inner peripheral surface 20a and positioned outside the inner space 22 and extending from the front edge of the inner peripheral surface 20a toward the opposite side of the inner space 22, and the outer surface of the top surface 20b An outer peripheral surface 20c that falls from the edge to the surface 10a of the substrate 10 and is formed in a rectangular shape in plan view (see FIG. 2). The shapes of the inner peripheral surface 20a and the outer peripheral surface 20c are not particularly limited, but from the viewpoint of improving the illuminance of the light emitting device 1, the inner peripheral surface 20a has a truncated cone shape (funnel shape) whose diameter increases as the distance from the substrate 10 increases. The outer peripheral surface 20 c is preferably formed in a quadrangular shape perpendicular to the substrate 10 from the viewpoint of improving the degree of integration of the light emitting device 1. In the drawing, as an example of forming the inner peripheral surface 20a, the lower part located on the substrate 10 side is perpendicular to the substrate 10, and the upper part located on the opposite side of the substrate 10 is separated from the substrate 10. An enlarged diameter is shown.

  The reflector 20 is made of a cured product of a thermosetting resin composition containing a white pigment. From the viewpoint of ease of forming the reflector 20, the thermosetting resin composition is preferably one that can be pressure-molded at room temperature (25 ° C.) before thermosetting.

  As the thermosetting resin contained in the thermosetting resin composition, various resins such as an epoxy resin, a silicone resin, a urethane resin, and a cyanate resin can be used. In particular, an epoxy resin is preferable because of its excellent adhesion to various materials.

  As the white pigment, alumina, magnesium oxide, antimony oxide, titanium oxide, or zirconium oxide can be used. Among these, titanium oxide is preferable from the viewpoint of light reflectivity. Inorganic hollow particles may be used as the white pigment. Specific examples of the inorganic hollow particles include sodium silicate glass, aluminum silicate glass, borosilicate soda glass, and shirasu.

  The transparent sealing resin 40 fills the inner space 22 formed by the inner peripheral surface 20a of the reflector 20 and seals the blue LED 30. The transparent sealing resin 40 is made of a transparent sealing resin having translucency. The transparent sealing resin includes a translucent resin as well as a completely transparent resin. The transparent sealing resin preferably has an elastic modulus of 1 MPa or less at room temperature (25 ° C.). In particular, it is preferable to employ a silicone resin or an acrylic resin from the viewpoint of transparency. The transparent sealing resin may further contain an inorganic filler that diffuses light and a phosphor 42 that emits white light using blue light emitted from the blue LED 30 as an excitation source.

  In the light emitting device 1 according to the present embodiment, the silver plating layer 16 is covered with the silver discoloration prevention film 50, and the transparent sealing resin 40 and the reflector 20 are joined.

  The silver discoloration prevention film 50 suppresses sulfidation of the silver plating layer 16 by covering the silver plating layer 16, and is formed from the silver discoloration prevention material of the present embodiment described above. When the silver discoloration-preventing material contains montmorillonite as clay, a film having a long gas path route and excellent gas barrier properties is formed as shown in FIG. 7, and further, this film is a halogen ion that is caused by the environment or remains in the material. And alkali metal ions can be further reduced, and discoloration due to silver migration can be suppressed.

  The film thickness of the silver discoloration preventing film 50 is preferably 0.01 μm or more and 1000 μm or less, more preferably 0.03 μm or more and 500 μm or less, further preferably 0.05 μm or more and 100 μm or less, and It is even more preferable that the thickness is from 05 μm to 10 μm, and it is particularly preferable that the thickness is from 0.05 μm to 1 μm. By setting the film thickness of the silver discoloration preventing film 50 to 0.01 μm or more and 1000 μm or less, both the gas barrier property with respect to the silver plating layer 16 and the transparency of the silver discoloration preventing film 50 can be achieved. In this case, this effect is further improved by setting the film thickness of the silver discoloration preventing film 50 to 0.03 μm to 500 μm, 0.05 μm to 100 μm, 0.05 μm to 10 μm, 0.05 μm to 1 μm. be able to. Further, since the silver discoloration preventing film 50 is formed from the silver discoloration preventing material of the present embodiment, cracks are hardly generated even in the above-described film thickness.

  The film thickness can be adjusted, for example, by changing the content of the solvent in the silver discoloration preventing material and appropriately adjusting the concentrations of the clay and the ion exchanger. Moreover, a film thickness can be adjusted also with the dripping amount and the frequency | count of dripping of a silver discoloration prevention material.

  From the viewpoint of improving the silver discoloration preventing performance of the silver discoloration preventing film, the total content of clay and ion exchanger in the silver discoloration preventing film 50 is preferably 5% by mass or more based on the total amount of the silver discoloration preventing film. It is more preferably 10% by mass or more, and particularly preferably 80% by mass or more.

  Next, a method for manufacturing the light emitting device 1 according to the first embodiment will be described.

  FIG. 3 is a flowchart illustrating the method for manufacturing the light emitting device according to the first embodiment. As shown in FIG. 3, in the method for manufacturing a light emitting device, first, as a substrate preparation step (step S <b> 101), an insulating base 12 having a copper plated plate 14 wired on the surface is prepared, and a silver plating layer formation step ( As step S102), the silver plating layer 16 is formed on the surface of the copper plating plate.

  Next, the reflector 20 is formed on the surface of the substrate 10 as a reflector forming step (step S103), and the blue LED 30 is mounted on the substrate 10 as a chip mounting step (step S104). The blue LED 30 is mounted on the substrate 10 by die-bonding the blue LED 30 to the silver plating layer 16 on either the anode side or the cathode side in the inner space 22 surrounded by the reflector 20. Thus, the blue LED 30 is electrically connected to the silver plating layer 16 on either the anode side or the cathode side through the die bonding material 32, and the blue LED 30 is surrounded by the reflector 20 and accommodated in the inner space 22. Become.

  Next, as a silver discoloration prevention material application step (step S105), the silver discoloration prevention material of this embodiment is applied to the silver plating layer 16 to cover the silver plating layer 16 with the silver discoloration prevention material.

  The silver discoloration prevention material is applied in the silver discoloration prevention material application step (step S105) by, for example, dropping or spraying the silver discoloration prevention material into the inner space 22 from the surface side of the substrate 10. At this time, the dripping amount or the spraying amount of the silver discoloration prevention material is adjusted so that at least all of the silver plating layer 16 is covered with the silver discoloration prevention material L. In this case, for example, as shown in FIG. 4A, the silver discoloration prevention material L is dropped or dispersed in the inner space 22 so that the silver plating layer 16 and the blue LED 30 are all covered with the silver discoloration prevention material L. As shown in FIG. 4B, the silver plating layer 16 and the blue LED 30 and a part of the inner peripheral surface 20a of the reflector 20 are covered with the silver discoloration preventing material L so as to cover the silver. The discoloration preventing material L may be dropped or dispersed in the inner space 22.

  Next, as a drying step (step S106), the silver discoloration preventing film 50 is formed by drying the coating film of the silver discoloration preventing material applied to the silver plating layer 16.

  The drying step can be performed at a temperature at which the solvent volatilizes. For example, when water is used as a solvent, the temperature is preferably 30 ° C. or higher and 80 ° C. or lower, and the temperature range is 30 ° C. or higher and 70 ° C. or lower. It is more preferable to set the temperature range to 30 ° C. or higher and 60 ° C. or lower. The time for maintaining this temperature range can be, for example, 1 minute or more, and is preferably 5 minutes or more and 1 day or less from the viewpoint of obtaining excellent film formability. More preferably, the time is from 30 minutes to 30 minutes.

  Further, the drying step when the solvent contains water and alcohol is, for example, preferably a temperature range of 30 ° C. or more and 80 ° C. or less, more preferably a temperature range of 35 ° C. or more and 80 ° C. or less, It is even more preferable that the temperature range be from 0C to 80C. The time for maintaining this temperature range can be, for example, 1 minute or longer, and is preferably 5 minutes or longer and 30 minutes or shorter from the viewpoint of obtaining excellent film formability. More preferably, the time is from 15 minutes to 15 minutes.

  By performing the drying process in this manner, the clay diluent L shown in FIG. 4A becomes a silver covering all of the silver plating layer 16 and the blue LED 30 as shown in FIG. 5A. The clay dilution liquid L shown in FIG. 4B becomes the discoloration prevention film 50, and as shown in FIG. 5B, all of the silver plating layer 16 and the blue LED 30 and the inner peripheral surface 20a of the reflector 20 are formed. A silver discoloration prevention film 50 covering a part of the film is formed.

  In the present embodiment, it is preferable to sufficiently dry the silver discoloration prevention film 50 under the conditions of 150 ° C. and 30 minutes after the drying step. Thereby, the effect of the further improvement of the silver discoloration prevention property by narrowing the interlayer of clay can be acquired.

  As shown in FIG. 3, when the drying process (step S106) is completed, the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are then wire-bonded as a wire bonding process (step S107). To do. At this time, the blue LED 30 and the silver plating layer 16 are bonded by bonding both ends of the wire to the blue LED 30 and the silver plating layer 16 so as to penetrate the silver discoloration prevention film 50 covered with the blue LED 30 and the silver plating layer 16. Is made conductive. The breakage of the silver discoloration prevention film 50 can be caused by, for example, adjusting the layer thickness of the silver discoloration prevention film 50, adjusting the load of the bonding head for wire bonding, or vibrating the bonding head. It can be carried out.

  Next, as the transparent sealing resin filling step (step S108), the inner space 22 formed by the inner peripheral surface 20a of the reflector 20 is filled with the transparent sealing resin 40 containing the phosphor 42. Thereby, blue LED30 and the silver plating layer 16 are sealed with the transparent sealing resin 40 (transparent sealing part).

  By performing the transparent sealing resin filling process in this way, the light emitting device 1 shown in FIG. 5A has all of the silver plating layer 16 and the blue LED 30 as shown in FIG. The light-emitting device 1 in which the silver plating layer 16 and the blue LED 30 are sealed with the transparent sealing resin 40 in the state of being covered with the silver discoloration prevention film 50 is illustrated in FIG. 6 (b), the silver plating layer 16 and the blue LED 30 in a state where all of the silver plating layer 16 and the blue LED 30 and a part of the inner peripheral surface 20a of the reflector 20 are covered with the silver discoloration prevention film 50. The LED 30 is the light emitting device 1 sealed with the transparent sealing resin 40.

  Thus, according to the manufacturing method of the light-emitting device 1 which concerns on 1st Embodiment, after covering the silver plating layer 16 with the silver discoloration prevention material of this embodiment, the coating film of a silver discoloration prevention material is dried. Thus, a silver discoloration preventing film 50 in which clay contained in the silver discoloration preventing material is laminated is formed, and the silver plating layer 16 is covered with the silver discoloration preventing film 50. Thereby, the silver discoloration prevention film | membrane 50 which can coat | cover the silver plating layer 16 appropriately can be formed.

  A silver discoloration preventing film that covers the silver plating layer can be easily formed by dropping or dispersing the silver discoloration preventing material of the present embodiment into the inner space 22 of the reflector 20 provided in the light emitting device 1.

[Second Embodiment]
Next, a second embodiment will be described. The manufacturing method of the light emitting device according to the second embodiment is basically the same as the manufacturing method of the light emitting device according to the first embodiment, but the manufacturing of the light emitting device according to the first embodiment only in the order of the steps. It is different from the method. For this reason, in the following description, only a part different from the method for manufacturing the light emitting device according to the first embodiment will be described, and description of the same part as the method for manufacturing the light emitting device according to the first embodiment will be omitted. .

  FIG. 8 is a flowchart showing a method for manufacturing the light emitting device according to the second embodiment. FIG. 9 is a cross-sectional view of a light emitting device manufactured by the manufacturing method of FIG.

  As shown in FIG. 8, in the method for manufacturing the light emitting device 1 according to the second embodiment, first, similarly to the first embodiment, a substrate preparation step (step S201) and a silver plating layer formation step (step S202). And a reflector formation process (step S203) is performed in this order. The substrate preparation step (step S201), the silver plating layer formation step (step S202), and the reflector formation step (step S203) are the substrate preparation step (step S101) and the silver plating layer formation step (steps) of the first embodiment. S102) and the reflector forming step (step S103).

  Next, as a silver discoloration prevention material application step (step S204), the silver discoloration prevention material of this embodiment is applied to the silver plating layer 16 to cover the silver plating layer 16 with the silver discoloration prevention material.

  Next, as a drying step (step S205), the silver discoloration preventing film 50 is formed by drying the coating film of the silver discoloration preventing material applied to the silver plating layer 16. The drying process (step S205) can be performed in the same manner as the drying process (step S106) of the first embodiment.

  Next, as a chip mounting step (step S206), the blue LED 30 is die-bonded to one of the silver plating layer 16 on the anode side and the cathode side. At this time, similarly to the wire bonding step (step S107) of the first embodiment, the blue LED 30 is bonded to the silver plating layer 16 so as to break through the silver discoloration prevention film 50 covered with the silver plating layer 16. The blue LED 30 and the silver plating layer 16 are electrically connected.

  Next, as a wire bonding step (step S207), the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are wire bonded. At this time, since the silver plating layer 16 is covered with the silver discoloration prevention film 50, the silver discoloration prevention film covered with the silver plating layer 16 is the same as in the wire bonding step (step S107) of the first embodiment. One end of the wire is bonded to the silver plating layer 16 so as to break through 50. On the other hand, since the blue LED 30 is not covered with the silver discoloration prevention film 50, the other end of the bonding wire 34 can be bonded to the blue LED 30 as usual. Thereby, blue LED30 and the silver plating layer 16 are conduct | electrically_connected.

  Next, a transparent sealing resin filling step is performed as step S208.

  As described above, according to the method for manufacturing the light emitting device according to the second embodiment, the chip mounting process is performed after the silver discoloration preventing material coating process and the drying process, thereby, as shown in FIG. The light emitting device 1 that is not covered with the silver discoloration prevention film 50 can be manufactured. Thereby, in the wire bonding step, when one end of the bonding wire 34 is bonded to the blue LED 30, it is not necessary to break through the silver discoloration prevention film 50 as in the method for manufacturing the light emitting device according to the first embodiment.

[Third Embodiment]
Next, a third embodiment will be described. The manufacturing method of the light emitting device according to the third embodiment is basically the same as the manufacturing method of the light emitting device according to the first embodiment, but only the order of the steps is the manufacturing of the light emitting device according to the first embodiment. It is different from the method. For this reason, in the following description, only a part different from the method for manufacturing the light emitting device according to the first embodiment will be described, and description of the same part as the method for manufacturing the light emitting device according to the first embodiment will be omitted. .

  FIG. 10 is a flowchart showing a method for manufacturing the light emitting device according to the third embodiment. FIG. 11 is a cross-sectional view of a light emitting device manufactured by the manufacturing method of FIG.

  As shown in FIG. 10, in the manufacturing method of the light emitting device 1 according to the third embodiment, first, similarly to the first embodiment, a substrate preparation step (step S301) and a silver plating layer formation step (step S302). In this order. The substrate preparation step (step S301) and the silver plating layer formation step (step S302) are the same as the substrate preparation step (step S101) and the silver plating layer formation step (step S102) of the first embodiment.

  Next, as a silver discoloration prevention material application step (step S303), the silver discoloration prevention material of this embodiment is applied to the silver plating layer 16 and the silver plating layer 16 is covered with the silver discoloration prevention material. At this time, from the viewpoint of workability, it is preferable to apply a silver discoloration prevention material to the entire surface of the substrate 10 on which the silver plating layer 16 is formed, but the silver discoloration prevention material is covered so as to cover only the silver plating layer 16. It may be applied.

  Next, as a drying step (step S304), the silver discoloration preventing film 50 is formed by drying the coating film of the silver discoloration preventing material applied to the silver plating layer 16. The drying process (step S304) can be performed in the same manner as the drying process (step S106) of the first embodiment.

  Next, as a reflector forming step (step S305), the reflector 20 is formed on the surface of the substrate 10. At this time, when the silver discoloration prevention material is applied to the entire surface of the substrate 10 in the silver discoloration prevention material application step (step S303), the reflector 20 is applied to the surface of the silver discoloration prevention film 50 covering the surface of the substrate 10. Form.

  Next, as a chip mounting step (step S306), the blue LED 30 is die-bonded to one of the silver plating layer 16 on the anode side and the cathode side. At this time, similarly to the wire bonding step (step S107) of the first embodiment, the blue LED 30 is bonded to the silver plating layer 16 so as to break through the silver discoloration prevention film 50 covered with the silver plating layer 16. The blue LED 30 and the silver plating layer 16 are electrically connected.

  Next, as a wire bonding step (step S307), the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are wire bonded. At this time, since the silver plating layer 16 is covered with the silver discoloration prevention film 50, the silver discoloration prevention film covered with the silver plating layer 16 is the same as in the wire bonding step (step S107) of the first embodiment. One end of the wire is bonded to the silver plating layer 16 so as to break through 50. On the other hand, since the blue LED 30 is not covered with the silver discoloration prevention film 50, the other end of the bonding wire 34 can be bonded to the blue LED 30 as usual. Thereby, blue LED30 and the silver plating layer 16 are conduct | electrically_connected.

  Next, a transparent sealing resin filling process is performed as step S308.

  As described above, according to the method for manufacturing the light emitting device according to the third embodiment, the reflector forming step and the chip mounting step are performed after the silver discoloration preventing material applying step and the drying step, as shown in FIG. In addition, the light emitting device 1 in which the blue LED 30 is not covered with the silver discoloration prevention film 50 can be manufactured. Thereby, in the wire bonding step, when one end of the bonding wire 34 is bonded to the blue LED 30, it is not necessary to break through the silver discoloration prevention film 50 as in the method for manufacturing the light emitting device according to the first embodiment.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  In the embodiment described above, the blue LED 30 that generates blue light is used as the light-emitting diode that is bonded to the light-emitting device 1. However, a light-emitting diode that generates light other than blue may be used.

  Moreover, although the light-emitting device 1 of the said embodiment was demonstrated as a thing provided with the reflector 20 surrounding the blue LED 30, it is good also as a thing not provided with such a reflector 20. FIG.

According to the silver discoloration prevention material of the present embodiment, since a silver discoloration prevention film excellent in silver sulfidation prevention property can be formed, Y ₂ O ₂ S: Eu (red) conventionally used as a phosphor, Sufficient sulfidation resistance can be obtained even with a light-emitting device using a sulfur-containing compound such as ZnS: Cu (green), ZnS: Ag (blue), or a compound disclosed in JP-A-8-085787. .

  The silver discoloration preventing material of the present embodiment can be applied to, for example, a plasma display, a liquid crystal display, and the like mounted with an LED including a lead frame containing silver, in addition to the light emitting device described above.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

(Preparation of 2 mass% water / isopropanol dilution A of Kunipia F)
In a container, 88 g of ultrapure water and 2 g of Kunipia F (Kunimine Kogyo Co., Ltd., product name) powder were placed, and the container was shaken by hand and stirred. After further adding 10 g of isopropanol in this container, mixing was performed at 2000 rpm for 20 minutes using an autorotation / revolution mixer (ARE-310, manufactured by Sinky Corporation), and then defoaming was performed at 2200 rpm for 10 minutes. A 2% by weight water / isopropanol dilution A was obtained.

(Preparation of 1% by weight water / isopropanol dilution B of IXE-300)
In a container, put 89 g of ultrapure water, 1 g of IXE-300 (product name, manufactured by Towa Gosei Co., Ltd.) and 10 g of isopropanol, and use a rotating / revolving mixer (ARE-310, manufactured by Sinky Corporation) for 20 minutes at 2000 rpm. Then, the mixture was degassed at 2200 rpm for 10 minutes to obtain a water / isopropanol diluent B having a concentration of IXE-300 of 1% by mass.

<Preparation of silver discoloration prevention material>
(Preparation Example 1)
In a container, 92.6 g of diluted solvent obtained by mixing ultrapure water and isopropanol at a mass ratio of 9/1, 7 g of diluted solution A, and 1.5 g of diluted solution B were placed, and a rotating / revolving mixer (ARE-310, manufactured by Shinky Corporation). ) For 20 minutes at 2000 rpm and then degassed for 10 minutes at 2200 rpm. Thus, a silver discoloration preventing material having a water / isopropanol mass ratio of 90/10, a clay concentration of 0.14% by mass, and an ion exchanger concentration of 0.015% by mass was obtained.

(Preparation Examples 2-3)
A silver discoloration prevention material was prepared in the same manner as in Preparation Example 1, except that the concentration of the diluent B was changed to 0.007% by mass and 0.35% by mass of the ion exchanger (IXE-300). Prepared.

(Preparation Example 4)
A water / isopropanol diluent diluted solution C having a concentration of IXE-100 of 1% by mass was prepared in the same manner as the diluent B except that 1 g of IXE-100 was blended in place of IXE-300.

  Next, silver having a clay concentration of 0.14% by mass and an ion exchanger concentration of 0.035% by mass was prepared in the same manner as in Preparation Example 1 except that the diluent C was used instead of the diluent B. An anti-discoloring material was prepared.

(Preparation Example 5)
A water / isopropanol diluent diluted solution D having a concentration of IXE-500 of 1% by mass was prepared in the same manner as the diluent B except that 1 g of IXE-500 was added instead of IXE-300.

  Next, silver having a clay concentration of 0.14% by mass and an ion exchanger concentration of 0.035% by mass was prepared in the same manner as in Preparation Example 1 except that the diluent D was used instead of the diluent B. An anti-discoloring material was prepared.

(Preparation Example 6)
A water / isopropanol diluent diluted solution E having a concentration of IXE-600 of 1% by mass was prepared in the same manner as the diluent B except that 1 g of IXE-600 was blended in place of IXE-300.

  Next, silver having a clay concentration of 0.14% by mass and an ion exchanger concentration of 0.035% by mass was prepared in the same manner as in Preparation Example 1, except that diluent E was used instead of diluent B. An anti-discoloring material was prepared.

(Preparation Example 7)
A water / isopropanol diluent diluted solution F having a concentration of IXE-700 of 1% by mass was prepared in the same manner as the diluent B except that 1 g of IXE-700 was added instead of IXE-300.

  Next, silver having a clay concentration of 0.14% by mass and an ion exchanger concentration of 0.035% by mass was prepared in the same manner as in Preparation Example 1 except that the diluent F was used instead of the diluent B. An anti-discoloring material was prepared.

(Preparation Examples 8-12)
Diluted with water / isopropanol with a concentration of MEB-3 of 2% by mass in the same manner as the preparation of diluent A, except that 2 g of MEB-3 (product name, manufactured by Co-op Chemical Co., Ltd.) was used instead of Kunipia F Liquid G was obtained.

  Next, in the same manner as in Preparation Examples 4, 3, 5, 6 or 7 except that the diluent G was used in place of the diluent A, the clay concentration was 0.14% by mass and the ion exchanger concentration. A silver discoloration preventing material having a content of 0.035% by mass was prepared.

(Preparation Examples 13-17)
A water / isopropanol diluted solution H having a ST concentration of 2% by mass was obtained in the same manner as in the preparation of the diluted solution A except that 2 g of stevensite (ST) (in-house synthesized product) was blended in place of Kunipia F.

  Next, in the same manner as in Preparation Examples 4, 3, 5, 6 or 7 except that the diluent H was used instead of the diluent A, the clay concentration was 0.14% by mass and the ion exchanger concentration. A silver discoloration preventing material having a content of 0.035% by mass was prepared.

(Preparation Example 18)
Diluent A was further diluted with a water / isopropanol mass ratio of 90/10 to prepare Diluent I having a clay concentration of 0.14% by mass.

(Preparation Example 19)
Diluent J having a clay concentration of 0.14% by mass was prepared in the same manner as Diluent I except that MEB-3 (product name, manufactured by Corp Chemical Co., Ltd.) was used instead of Kunipia F.

(Preparation Example 20)
Prepare Diluent K with a clay concentration of 0.14% by mass in the same manner as Diluent I, except that Steven Sight (ST) (Hitachi Chemical Industry Co., Ltd. in-house synthesized product) was used instead of Kunipia F. did.

<Suppression of silver discoloration at high temperature and high humidity>
About the silver discoloration prevention material produced above, the discoloration suppression effect of silver plating was evaluated according to the following "high temperature high humidity test".

[High temperature and high humidity test]
1. 3 μl of silver discoloration prevention material was dropped on “TOP LED OP4” (manufactured by Enomoto Co., Ltd.), which is an LED lead frame having a silver plating layer provided on a copper plate, with a micropipette.
2. A lead frame in which a silver discoloration preventing material was dropped and a lead frame not coated with a silver discoloration preventing material as a control were placed in a thermostatic bath and dried at 50 ° C. for 10 minutes.
3. After drying, the temperature of the thermostatic bath was raised to 150 ° C., heated for 1 hour, allowed to cool in a desiccator, and then filled with KER-2600 (dimethyl silicone manufactured by Shin-Etsu Chemical Co., Ltd.) into the reflector cavity with a dispenser. This was heated at 100 ° C. for 1 hour, and then heated at 150 ° C. for 3 hours to obtain a package test sample.
4). 3. above. The package sample produced in (1) was mounted on a substrate to produce an evaluation substrate.
5. 4. above. The power supply was connected to the evaluation board | substrate produced in (3), 30 mA, 3V electric current was sent in the 85 degreeC and 85RH% thermostat, and LED was lighted.
6). After lighting for 20 hours, the sample was taken out from the thermostat and the degree of discoloration was observed with a microscope.
7). Compared with the product without silver discoloration prevention material applied, “○” indicates that the discolored portion is significantly reduced, “△” indicates that the discolored portion is partially reduced, and “×” indicates that no change is seen and no effect. It was. The results are shown in Table 1.

<Evaluation of silver discoloration prevention>
About the silver discoloration prevention material produced above, silver discoloration prevention property was evaluated according to the following “sulfur test 1”.

[Sulfur test 1]
1. 3 μl of silver discoloration prevention material was dropped on “TOP LED OP4” (manufactured by Enomoto Co., Ltd.), which is an LED lead frame having a silver plating layer provided on a copper plate, with a micropipette.
2. A lead frame in which a silver discoloration preventing material was dropped was placed in a thermostatic bath and dried at 50 ° C. for 10 minutes.
3. After drying, the temperature of the thermostatic bath was raised to 150 ° C. and heated for 30 minutes to obtain a test sample.
4). An aluminum cup containing sulfur powder (0.5 g) was placed in a sealable glass bottle, and a stainless steel wire mesh was placed on the cup. Next, the test sample obtained in the above 3 was placed on the wire mesh so that the samples were not overlapped with the side on which the silver discoloration preventing material was dropped.
5. After sealing the glass bottle, it was stored at 80 ° C. for 4 hours.
6). The test sample was taken out from the glass bottle, and the presence or absence of sulfuration of the entire surface of the silver plating layer and the end portion was confirmed with an optical microscope.
7). Three test samples were prepared for each, and the number of sulfur samples in which no sulfidation was observed is shown in Table 1.

<Evaluation of adhesion>
About the silver discoloration prevention material produced above, adhesiveness was evaluated according to the following "adhesion power test".

[Adhesion test]
1. 1 μl of silver discoloration preventing material was dropped with a micropipette on a substrate before forming a white resin reflector of “TOP LED OP4” (manufactured by Enomoto Co., Ltd.) which is an LED lead frame having a silver plating layer provided on a copper plate.
2. A lead frame in which a silver discoloration-preventing material was dropped was placed in a thermostat and dried at 50 ° C. for 10 minutes.
3. After drying, the temperature of the thermostatic bath was raised to 150 ° C. and heated for 1 hour to obtain a test sample.
4). Adhesive tape "DP-1010" (manufactured by Hitachi Chemical Co., Ltd.) is bonded to the obtained test sample, and the angle formed by the tape and the test sample is 90 degrees when the test sample is viewed from the horizontal direction. Slowly peeled off.
5. The test sample from which the tape was peeled was observed, and “○” represents that the silver discoloration prevention material was held without peeling, and “x” represents that the tape was transferred to the tape side.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 10 ... Board | substrate, 10a ... Surface of board | substrate, 12 ... Base | substrate, 14 ... Copper plating board, 16 ... Silver plating layer, 20 ... Reflector (light reflection part), 20a ... Inner peripheral surface, 20b ... Top surface 20c ... outer peripheral surface, 22 ... inner space, 30 ... blue LED (blue light emitting diode), 32 ... die bond material, 34 ... bonding wire, 40 ... transparent sealing resin (transparent sealing portion), 42 ... phosphor, 50 ... Silver discoloration prevention film, L ... Silver discoloration prevention material.

Claims (9)

Containing clay and an ion exchanger ,
i) The clay includes a steven site, and the ion exchanger is selected from (a) a zirconia ion exchanger, (b) an antimony ion exchanger, and (c) a hydrotalcite ion exchanger. Containing one or more ion exchangers, or
ii) The clay contains one or more of smectite and mica, and the ion exchanger is one or more of (a) a zirconia ion exchanger and (b) an antimony ion exchanger. including,
Silver discoloration prevention material.   The silver discoloration prevention material according to claim 1 whose mass ratio of said clay and said ion exchanger is 95/5-70/30. On the surface of the metal layer containing silver, an application step of applying the silver discoloration prevention material according to claim 1 or 2 to form a coating film of the silver discoloration prevention material;
A drying step of drying the coating film;
A method for forming a silver discoloration preventing film. The method for forming a silver discoloration prevention film according to claim 3 , wherein the metal layer is a silver plating layer. A method for manufacturing a light emitting device, comprising: a substrate having a silver plating layer; and a light emitting element mounted on the substrate,
On the surface of the silver plating layer, an application step of applying the silver discoloration prevention material according to claim 1 or 2 to form a coating film of the silver discoloration prevention material;
A drying step of drying the coating film;
A method for manufacturing a light emitting device. The method for manufacturing a light-emitting device according to claim 5, further comprising a step of providing at least a transparent sealing resin for sealing the light-emitting element after the drying step. A substrate having a silver plating layer, a light emitting element mounted on the substrate, and a silver discoloration prevention film provided on the surface of the silver plating layer,
The silver discoloration preventing film contains clay and an ion exchanger ,
i) The clay includes a steven site, and the ion exchanger is selected from (a) a zirconia ion exchanger, (b) an antimony ion exchanger, and (c) a hydrotalcite ion exchanger. Containing one or more ion exchangers, or
ii) The clay contains one or more of smectite and mica, and the ion exchanger is one or more of (a) a zirconia ion exchanger and (b) an antimony ion exchanger. including,
Light emitting device. The light-emitting device of Claim 7 whose mass ratio of the said clay and the said ion exchanger in the said silver discoloration prevention film is 95/5-70/30. The light-emitting device according to claim 7, further comprising a transparent sealing resin that seals at least the light-emitting element.

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