JP6003013B2 - Light emitting device - Google Patents

Description

  The present invention relates to a surface treatment agent for silver and silver alloy, and more particularly to a surface treatment agent for preventing discoloration of silver and silver alloy used in electronic parts and light emitting devices. The present invention also relates to a substrate with a light reflection film and a light emitting device including a light reflection film made of silver or a silver alloy.

  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 diode is used in applications such as lighting equipment and automobile lights. In such a light emitting device, the light extraction efficiency is improved by providing a light reflecting film made of silver or a silver alloy.

  However, since silver and silver alloys are chemically very unstable, when they react with oxygen, moisture, hydrogen sulfide, sulfurous acid gas, etc. in the air, silver oxide and silver sulfide are produced and the surface becomes brown or black. Discolor. Such discoloration leads to a decrease in light reflectance, and decreases the light emission intensity of the light emitting device.

  As a method for preventing discoloration of silver and a silver alloy, for example, Patent Document 1 below proposes a silver coating composition containing a zirconium complex of a carboxylic acid and a silicon acrylic resin component. Patent Document 2 below proposes a surface treatment agent for silver and a silver alloy containing a specific imidazole compound. Further, Patent Document 3 below discloses that sulfidation of silver plating provided on the surface of the LED package substrate can be suppressed by an optical semiconductor element sealing resin containing a specific organopolysiloxane.

JP 10-158572 A JP 2004-238658 A JP 2010-248413 A

  The treatment agents described in Patent Documents 1 and 2 have a drawback of low resistance to ultraviolet rays and discoloration due to long-term exposure to ultraviolet rays. Since light emitting diodes used in lighting equipment and automotive applications emit near ultraviolet light, it is difficult to sufficiently maintain the light emission intensity over a long period of time even if the treatment agent is applied to the light reflecting film of the light emitting device including the light emitting diode. is there.

  On the other hand, in addition to insufficient malleability, the sealing resin described in Patent Document 3 is bonded by stress generated due to heat generated during driving when used as a sealing material for a light emitting diode. May peel from the surface. Such peeling causes a decrease in gas shielding properties, and the discoloration of silver and silver alloy cannot be sufficiently suppressed.

  The present invention has been made in view of the above circumstances, and is a silver and silver alloy surface treatment agent capable of imparting excellent color fastness to the surface of silver and silver alloys, and light reflection excellent in color fastness. It is an object of the present invention to provide a film-coated substrate and a light-emitting device in which light emission intensity is unlikely to decrease.

  In order to solve the above-mentioned problems, the present inventors diligently studied, and as a result, by applying a surface treatment agent containing smectite and a water-soluble polymer on a substrate on which silver was deposited, the substrate was resistant to hydrogen sulfide. Has been found to improve, and the present invention has been completed.

  That is, the present invention provides a surface treatment agent for silver and a silver alloy containing smectite and a water-soluble polymer.

  According to the surface treatment agent for silver and silver alloy of the present invention, excellent discoloration resistance can be imparted to the surface of silver and silver alloy by applying to the surface of silver and silver alloy.

  The present inventors consider the reason why the above effect can be obtained by the surface treating agent of the present invention as follows. That is, by using a smectite and a water-soluble polymer in combination, plate-like smectite particles can be laminated on silver and a silver alloy with a sufficient adhesive force. The present inventors consider that the hydrogen sulfide gas in the atmosphere, which is a discoloration factor, can be sufficiently shielded. In addition, it is considered that the stress at the interface between smectite particles and silver or a silver alloy is relaxed by the water-soluble polymer as a reason for improving the adhesive force.

  From the viewpoint of suppressing discoloration of silver and silver alloy, the solid mass ratio of smectite and water-soluble polymer is preferably 95/5 to 50/50.

  In addition, the smectite is preferably one or more of stevensite, hectorite, saponite, montmorillonite, and beidellite from the viewpoint of the shielding property of hydrogen sulfide gas.

  Furthermore, from the viewpoint of maintaining the original gloss of silver and silver alloys, the smectite is preferably a synthetic smectite.

  In addition, in terms of affinity with smectite and stress relaxation at the interface with silver or a silver alloy, the water-soluble polymer is any one of carboxymethylcellulose salt, polyacrylate, polyvinyl alcohol and polyvinylpyrrolidone. One or more types are preferred.

  The present invention also includes a substrate and a light reflecting film made of silver or a silver alloy provided on the substrate, and at least a film formed of the surface treatment agent of the present invention is provided on the surface of the light reflecting film. A substrate with a light reflecting film is provided.

  The substrate with a light reflecting film of the present invention has a light reflecting film excellent in color fastness due to the film formed from the surface treating agent of the present invention formed on the light reflecting film made of silver or a silver alloy. be able to.

  The present invention also provides a light emitting device comprising a light emitting diode and the substrate with the light reflecting film of the present invention. According to the light emitting device of the present invention, since the light reflecting film having excellent discoloration resistance is provided, the light emission intensity obtained from the light emitting diode can be sufficiently maintained over a long period of time.

  According to the present invention, silver and a silver alloy surface treatment agent capable of imparting excellent color fastness to the surface of silver and a silver alloy, a substrate with a light reflecting film excellent in color fastness, and emission intensity. It is possible to provide a light-emitting device that does not easily decrease.

  ADVANTAGE OF THE INVENTION According to this invention, discoloration and corrosion of silver and a silver alloy which are used for an illumination device provided with an electronic component, a light emitting diode, etc. can fully be prevented, for example. According to the present invention, it is possible to provide a surface treating agent that can give excellent discoloration resistance particularly to a silver deposited surface. In addition, according to the present invention, it is possible to provide a substrate made of silver or a silver alloy and having a light reflecting film excellent in color fastness, and to improve the light extraction efficiency and long-term stabilization of the light emitting diode. it can.

It is a schematic cross section which shows one Embodiment of the board | substrate with a light reflection film which concerns on this invention. 1 is a schematic cross-sectional view showing an embodiment of a light emitting device according to the present invention.

  The surface treatment agent for silver and silver alloy of the present invention is characterized by containing smectite and a water-soluble polymer as essential components.

  Examples of the silver alloy include silver-bismuth alloy, silver-neodymium alloy, silver-copper alloy, silver-magnesium alloy, silver-zinc alloy, silver-tin alloy, silver-indium alloy, silver-titanium alloy, silver-zirconium. Examples include alloys, silver-gold alloys, silver-palladium alloys, and silver-platinum alloys.

  The smectite contained in the surface treatment agent of the present invention is a particle having a plate shape having a thickness of 0.9 to 1.5 nm and a length in the diameter direction of 10 to 400 nm, and is mixed with a solvent such as water and alcohol. Those having the property of swelling and dispersing in a solvent are used.

  As the smectite, any one or more of stevensite, hectorite, saponite, montmorillonite, and beidellite can be suitably used. These smectites are smectite particles having a flat plate shape with a thickness of 0.9 to 1.5 nm and a length in the diameter direction of 10 to 400 nm, and are laminated on silver or a silver alloy, for example, hydrogen sulfide. Gas shielding properties such as can be expressed.

  From the viewpoint of maintaining the gas shielding properties and the original gloss of silver and silver alloy, the length in the diameter direction of the smectite particles is preferably 10 to 400 nm, more preferably 10 to 200 nm, and more preferably 10 to 100 nm. More preferably.

  Note that the length in the diameter direction of the smectite particles can be measured by using, for example, a transmission electron microscope. When the smectite particle shape is not circular, for example, in the case of an ellipse, the longest diameter is calculated as the length in the diameter direction.

  The smectite contained in the surface treatment agent of the present invention is preferably a synthetic product from the viewpoint of maintaining the original gloss of silver and silver alloys.

  When smectites other than synthetic products, for example, natural smectites produced from soil, are used, impurities such as iron ions are contained in the components even after purification, so that the smectite may be colored brown. As a result, when silver and silver alloy are coated, the surface is colored and the original gloss of silver and silver alloy tends to be lowered.

  In addition, as a synthesis method of a smectite, a hydrothermal synthesis method can be used suitably, for example.

  As the water-soluble polymer contained in the surface treatment agent of the present invention, those having the property of being swollen by being mixed with a solvent such as water and alcohol and dispersed in the solvent, like smectite, are used.

  As the water-soluble polymer, any one or more of carboxymethyl cellulose salt, polyacrylic acid salt, polyvinyl alcohol, and polyvinyl pyrrolidone can be suitably used.

  Examples of the carboxymethyl cellulose salt include carboxymethyl cellulose ammonium and carboxymethyl cellulose sodium. Examples of the polyacrylate include sodium polyacrylate and ammonium polyacrylate.

  The molecular weight of the water-soluble polymer is preferably 10,000 to 100,000, more preferably 15,000 to 80,000, and even more preferably 30,000 to 60,000.

  The surface treatment agent of the present invention imparts excellent discoloration resistance on silver or a silver alloy by applying a solvent containing water and alcohol or the like onto silver or a silver alloy and then removing the solvent. In particular, excellent discoloration resistance can be imparted to the silver deposited surface. Such an effect is obtained by using a smectite and a water-soluble polymer in combination, so that plate-like smectite particles can be laminated on silver and a silver alloy with sufficient adhesive force. In addition, the present inventors consider that the hydrogen sulfide gas in the atmosphere, which is a color change factor of the silver alloy, can be sufficiently shielded. In addition, it is considered that the stress at the interface between smectite particles and silver or a silver alloy is relaxed by the water-soluble polymer as a reason for improving the adhesive force.

  As a method for applying the surface treating agent of the present invention, for example, methods such as bar coating, dip coating, spin coating, spray coating, and potting can be suitably used.

  Examples of the method for removing the solvent from the coating film of the surface treatment agent of the present invention include drying at a temperature of room temperature or higher, and heating at 20 to 80 ° C. is preferable from the viewpoint of maintaining the shielding property of hydrogen sulfide gas.

  The solid mass ratio of smectite and water-soluble polymer in the surface treatment agent of the present invention is preferably 95/5 to 50/50.

  If the solid mass ratio is larger than 95/5 and the smectite content is too high, the adhesion improving effect by the water-soluble polymer is difficult to obtain, so the adhesion of the smectite particles on the silver and the silver alloy decreases. Further, the amount of gas transmission of hydrogen sulfide or the like from the adhesion interface increases, and it becomes difficult to obtain the effect of suppressing discoloration of silver and the silver alloy. On the other hand, when the solid mass ratio is less than 50/50 and the water-soluble polymer content is excessively increased, the content of smectite particles having gas shielding properties is decreased, so that the gas permeation amount of hydrogen sulfide and the like is increased. It becomes difficult to obtain the discoloration suppressing effect of silver and silver alloy.

  The solid mass ratio is 90/10 to 50/50 from the viewpoint of improving the adhesion to silver and the silver alloy and gas shielding properties such as hydrogen sulfide, and obtaining the effect of suppressing discoloration of the silver and the silver alloy more reliably. More preferably, it is more preferably 80/20 to 50/50.

  As a solvent used for the surface treating agent of the present invention, water is preferably used. As a solvent other than water, polar solvents such as methanol, ethanol, and propanol can also be used.

  The total content of smectite and water-soluble polymer in the surface treatment agent of the present invention is preferably 0.005 to 2% by mass, and 0.01 to 1.5% by mass in terms of the solid component concentration. Is more preferable, and it is still more preferable that it is 0.05-1 mass%. In this case, for example, a film having excellent shielding properties against hydrogen sulfide gas, which is a color change factor of silver and silver alloy, can be easily formed on the surface of silver and silver alloy.

  Various additives can be added to the surface treatment agent of the present invention as long as the effects of the present invention are not impaired.

  According to the surface treatment agent of the present invention, silver or a silver alloy having discoloration resistance is provided by forming a film made of a solid component contained in the surface treatment agent of the present invention on the surface of silver or a silver alloy. can do. Specifically, after applying the surface treatment agent of the present invention on silver or a silver alloy, the solvent is removed to remove smectite contained in the surface treatment agent of the present invention on the silver or silver alloy. A film made of molecules can be formed.

  As a preferred embodiment, for example, a substrate and a light reflecting film made of silver or a silver alloy provided on the substrate are provided, and at least the surface of the light reflecting film is formed from the surface treatment agent of the present invention. A substrate with a light reflecting film provided with a film is mentioned. FIG. 1 is a schematic cross-sectional view showing an embodiment of a substrate with a light reflecting film according to the present invention. A substrate 10 with a light reflecting film shown in FIG. 1 includes a substrate 1 and a light reflecting film 2 made of silver or a silver alloy provided on the substrate 1. Examples of the material of the substrate 1 include ceramic, resin, and metal. On the light reflection film 2, a film formed of the surface treatment agent according to the present invention is provided.

  The substrate with a light reflecting film of this embodiment is suitable as an LED package substrate.

  Examples of the light emitting device of the present invention include a light emitting device including a light emitting diode and the substrate with the light reflecting film. FIG. 2 is a schematic cross-sectional view showing an embodiment of a light emitting device according to the present invention. The light emitting device 20 shown in FIG. 2 is provided on the substrate 1, the reflection plate 5 provided on the substrate 1, the light reflection film 2 provided on the substrate 1 and the reflection plate 5, and the substrate 1. The LED chip 4 is electrically connected by a metal wire 3. Examples of the material of the substrate 1 include ceramic, resin, and metal. Examples of the material of the reflecting plate 5 include ceramic, resin, and metal. On the light reflection film 2, a film formed of the surface treatment agent according to the present invention is provided.

  Examples of the electronic component to which the surface treatment agent of the present invention can be applied include a plasma display and a liquid crystal display including silver or a silver alloy as an antireflection film.

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

<Combination of steven sites>
(Synthesis Example 1)
20 ml of nitric acid was added to a dispersion obtained by mixing 60 g of colloidal silica (Ludox ™ 50, manufactured by SigmaAldrich) and 120 ml of distilled water. A solution prepared by mixing 91 g of magnesium nitrate (primary reagent) and 128 ml of distilled water was added thereto, and ammonia water (28% aqueous solution) was slowly added dropwise with stirring. The dripping was stopped when the pH reached 10, and the mixture was aged at room temperature overnight to obtain a uniform composite precipitate. Thereafter, water washing by adding distilled water, shaking, and solid-liquid separation was repeated until the ammonia odor disappeared. 25.4 ml of a 10% by weight lithium hydroxide aqueous solution was added to the well-mixed homogeneous composite precipitation dispersion and thoroughly mixed to obtain a starting raw material slurry. The starting material slurry was charged into an autoclave and hydrothermally reacted at 200 ° C. for 48 hours. After cooling, the reaction product in the autoclave was taken out, dried at 60 ° C., and then pulverized to obtain a smectite classified as a steven site.

<Production of surface treatment agent>
Example 1
In a container, put 0.9g of stevensite obtained in Synthesis Example 1 as smectite and 0.1g of carboxymethylcellulose ammonium (Daicel Chemical Industries, DN-800H) as water-soluble polymer, and add distilled water. Then, after setting the total mass to 100 g, the mixture was mixed at 2000 rpm for 10 minutes and defoamed at 2200 rpm for 10 minutes using a rotating / revolving mixer (ARE-310, manufactured by Sinky Corporation). Thus, a surface treatment agent having a smectite / water-soluble polymer solid mass ratio of 90/10 and a concentration of 1% by mass was obtained.

(Example 2)
A surface treatment agent was prepared in the same manner as in Example 1 except that the solid mass ratio of smectite / water-soluble polymer was 80/20.

(Example 3)
A surface treating agent was prepared in the same manner as in Example 1 except that the solid mass ratio of smectite / water-soluble polymer was 60/40.

Example 4
A surface treatment agent was produced in the same manner as in Example 1 except that the concentration of the surface treatment agent was changed to 0.5% by mass.

(Example 5)
A surface treatment agent was produced in the same manner as in Example 1 except that the concentration of the surface treatment agent was changed to 0.2% by mass.

(Example 6)
A surface treatment agent was produced in the same manner as in Example 1 except that the concentration of the surface treatment agent was changed to 0.1% by mass.

(Example 7)
A surface treatment agent was prepared in the same manner as in Example 4 except that ammonium polyacrylate (Toagosei Co., Ltd., A-6114) was used as the water-soluble polymer.

(Example 8)
A surface treatment agent was produced in the same manner as in Example 7 except that the concentration of the surface treatment agent was changed to 0.2% by mass.

Example 9
A surface treatment agent was prepared in the same manner as in Example 7 except that the concentration of the surface treatment agent was changed to 0.1% by mass.

(Example 10)
A surface treatment agent was prepared in the same manner as in Example 4 except that saponite (Kunimine Industries, Ltd., Smecton SA) was used as the smectite.

(Comparative Example 1)
A surface treatment agent was prepared in the same manner as in Example 1 except that the water-soluble polymer was not blended.

(Comparative Example 2)
A surface treating agent was prepared in the same manner as in Example 1 except that smectite was not blended.

<Surface treatment of silver substrate>
The surface treatment agent prepared above was applied onto a silver substrate on which 100 nm thick silver was deposited on a soda glass slide glass using a bar coater having a wet thickness of 12 μm, and then allowed to stand at 22 ° C. for 12 hours. Then, the solvent was removed to obtain surface-treated silver substrates each having a silver-deposited surface treated.

<Production of light emitting device>
A light emitting diode was manufactured by connecting a light emitting diode chip having a light emission wavelength of 467.5 nm to 470 nm and a capacity of 3.7 μL with a gold wire on a silver plating substrate (substrate for LED mounting). Then, 0.2 mL of the surface treatment agent prepared above is dropped on the silver plating of the light emitting device with a potting method, that is, a dropper, and left at 22 ° C. for 12 hours to remove the solvent, and the surface treatment is performed on the silver plating. Each of the light emitting devices to which was applied was obtained.

[Evaluation of hydrogen sulfide gas resistance of surface-treated silver substrate]
The visible light reflectance of the surface-treated silver substrate at a wavelength of 550 nm was measured using a spectrophotometer (JASCO, V-570), and this was defined as [reflectance before exposure to hydrogen sulfide]. Next, the surface-treated silver substrate was allowed to stand in a 10 ppm hydrogen sulfide gas stream at 40 ° C. and 90% RH for 96 hours, and then the visible light reflectance at a wavelength of 550 nm was measured. Rate]. And the reflection fall rate was calculated | required from the following formula. The results are shown in Table 1.
[Reflectance reduction rate] = [Reflectivity before exposure to hydrogen sulfide] − [Reflectivity after exposure to hydrogen sulfide]
It can be determined that the smaller the reflection reduction rate, the better the resistance to hydrogen sulfide gas.

[Evaluation of hydrogen sulfide gas resistance of surface-treated light-emitting devices]
The surface-treated light emitting device emits light at a forward current of 20 mA and a forward voltage of 3.3 V, and the light emission intensity is measured with an exposure time of 30 milliseconds using a multiphotometer (Otsuka Electronics Co., Ltd., MCPD-3700). Was defined as [emission intensity before exposure to hydrogen sulfide]. Next, the surface-treated light emitting device was allowed to stand in a 10 ppm hydrogen sulfide gas stream, 40 ° C., 90% RH for 96 hours, and then allowed to emit light at a forward current of 20 mA and a forward voltage of 3.3 V. The emission intensity was measured at an exposure time of 30 milliseconds, and this was defined as [emission intensity after exposure to hydrogen sulfide]. And the light emission intensity maintenance factor was calculated | required from the following formula. The results are shown in Table 1.
[Emission intensity maintenance ratio] = ([Emission intensity after exposure to hydrogen sulfide] / [Emission intensity before exposure to hydrogen sulfide]) × 100
It can be determined that the higher the emission intensity maintenance rate, the better the resistance to hydrogen sulfide gas.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Light reflection film, 3 ... Metal wire, 4 ... LED chip, 5 ... Reflection board, 10 ... Board | substrate with a light reflection film, 20 ... Light-emitting device.

Claims (20)

A substrate, a light reflecting film and a light emitting diode made of silver or a silver alloy provided on the substrate, and a metal wire connecting the substrate and the light emitting diode ,
At least the surface of the light reflecting film has a film containing smectite and a water-soluble polymer,
The light-emitting device whose solid mass ratio of the said smectite and the said water-soluble polymer in the said film | membrane is 95/5-50/50.   The light emitting device according to claim 1, wherein the smectite is one or more of stevensite, hectorite, saponite, montmorillonite, and beidellite.   The light emitting device according to claim 1, wherein the smectite is a synthetic smectite.   The light-emitting device according to any one of claims 1 to 3, wherein the water-soluble polymer is at least one of carboxymethylcellulose salt, polyacrylate, polyvinyl alcohol, and polyvinylpyrrolidone. A substrate, a light reflecting film and a light emitting diode made of silver or a silver alloy provided on the substrate, and a metal wire connecting the substrate and the light emitting diode ,
At least the surface of the light reflecting film has a film containing smectite and a water-soluble polymer,
The light emitting device, wherein the smectite is at least one of stevensite, hectorite, saponite, montmorillonite, and beidellite. The light-emitting device according to claim 5 , wherein the smectite is a synthetic smectite. The light-emitting device according to claim 5 or 6 , wherein the water-soluble polymer is at least one of carboxymethyl cellulose salt, polyacrylic acid salt, polyvinyl alcohol, and polyvinyl pyrrolidone. A substrate, a light reflecting film and a light emitting diode made of silver or a silver alloy provided on the substrate, and a metal wire connecting the substrate and the light emitting diode ,
At least the surface of the light reflecting film is provided with a film containing smectite and a water-soluble polymer,
The light emitting device, wherein the smectite is a synthetic smectite. The light-emitting device according to claim 8 , wherein the water-soluble polymer is at least one of carboxymethyl cellulose salt, polyacrylate, polyvinyl alcohol, and polyvinyl pyrrolidone. A substrate, a light reflecting film and a light emitting diode made of silver or a silver alloy provided on the substrate, and a metal wire connecting the substrate and the light emitting diode ,
At least the surface of the light reflecting film has a film containing smectite and a water-soluble polymer,
The light emitting device, wherein the water-soluble polymer is at least one of carboxymethyl cellulose salt, polyacrylate, polyvinyl alcohol, and polyvinyl pyrrolidone. A film comprising a substrate, a light reflection film and a light emitting diode made of silver or a silver alloy provided on the substrate, and containing at least a smectite and a water-soluble polymer on the surface of the light reflection film A method for manufacturing a light emitting device, comprising:
After connecting the substrate and the light emitting diode with a metal wire, the step of forming the film by applying a surface treatment agent containing smectite and a water-soluble polymer,
The manufacturing method of the light-emitting device whose solid mass ratio of the said smectite and the said water-soluble polymer in the said surface treating agent is 95/5-50/50. The manufacturing method of the light-emitting device according to claim 11 , wherein the smectite is any one or more of stevensite, hectorite, saponite, montmorillonite, and beidellite. The manufacturing method of the light-emitting device according to claim 11 or 12 , wherein the smectite is a synthetic smectite. The method for manufacturing a light-emitting device according to claim 11 , wherein the water-soluble polymer is at least one of carboxymethylcellulose salt, polyacrylate, polyvinyl alcohol, and polyvinylpyrrolidone. . A film comprising a substrate, a light reflection film and a light emitting diode made of silver or a silver alloy provided on the substrate, and containing at least a smectite and a water-soluble polymer on the surface of the light reflection film A method for manufacturing a light emitting device, comprising:
After connecting the substrate and the light emitting diode with a metal wire, the step of forming the film by applying a surface treatment agent containing smectite and a water-soluble polymer,
The method for producing a light-emitting device, wherein the smectite is any one or more of stevensite, hectorite, saponite, montmorillonite, and beidellite. The method for manufacturing a light-emitting device according to claim 15 , wherein the smectite is synthetic smectite. The method for producing a light emitting device according to claim 15 or 16 , wherein the water-soluble polymer is at least one of carboxymethyl cellulose salt, polyacrylic acid salt, polyvinyl alcohol, and polyvinyl pyrrolidone. A film comprising a substrate, a light reflection film and a light emitting diode made of silver or a silver alloy provided on the substrate, and containing at least a smectite and a water-soluble polymer on the surface of the light reflection film A method for manufacturing a light emitting device, comprising:
After connecting the substrate and the light emitting diode with a metal wire, the step of forming the film by applying a surface treatment agent containing smectite and a water-soluble polymer,
The manufacturing method of the light-emitting device whose said smectite is synthetic smectite. The method for producing a light-emitting device according to claim 18 , wherein the water-soluble polymer is at least one of carboxymethylcellulose salt, polyacrylate, polyvinyl alcohol, and polyvinylpyrrolidone. A film comprising a substrate, a light reflection film and a light emitting diode made of silver or a silver alloy provided on the substrate, and containing at least a smectite and a water-soluble polymer on the surface of the light reflection film A method for manufacturing a light emitting device, comprising:
After connecting the substrate and the light emitting diode with a metal wire, the step of forming the film by applying a surface treatment agent containing smectite and a water-soluble polymer,
The manufacturing method of the light-emitting device whose said water-soluble polymer is any one or more of carboxymethylcellulose salt, polyacrylic acid salt, polyvinyl alcohol, and polyvinylpyrrolidone.

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