WO2013047874A1

WO2013047874A1 - Reflective substrate for light-emitting element

Info

Publication number: WO2013047874A1
Application number: PCT/JP2012/075390
Authority: WO
Inventors: 堀田　吉則
Original assignee: 富士フイルム株式会社
Priority date: 2011-09-30
Filing date: 2012-10-01
Publication date: 2013-04-04
Also published as: JP2013083002A

Abstract

Provided is a reflective substrate for a light-emitting element, said reflective substrate exhibiting higher heat resistance, excellent light resistance and a high optical reflectance. The reflective substrate is provided with an inorganic reflective layer that covers a valve metal base at least partially, wherein the inorganic reflective layer has a Vickers hardness (Hv) of 1GPa or more and an absorbance difference between at a wavenumber of 3000cm^-1 and at a wavenumber of 1900cm^-1 of 0.40 or more as determined by infrared spectroscopy, said absorbance difference being correspondent to an absorption coefficient assignable to OH surface structure.

Description

Reflective substrate for light emitting device

The present invention relates to a light reflecting substrate used for a light emitting element, and more specifically to a light emitting element reflecting substrate used for a light emitting element such as a light emitting diode (hereinafter referred to as LED) and a method for manufacturing the same.

Patent Document 1 describes a coating composition in which a resin and a silica airgel are mixed, and the resin is a powder coating, and a reflector for a lighting fixture in which a coating film of the coating composition is formed on the surface of a metal substrate. Since the powder coating is a solid content of 100% resin and does not contain an organic solvent, the hydrophobic silica aerogel does not shrink due to the action of the organic solvent or the like and becomes cloudy. It is described that the light reflectance is excellent.

JP-A-11-29745

However, when the light reflecting substrate for a light emitting element contains a resin binder, there is a problem that the reflective layer itself has low heat resistance and poor light resistance, and cannot withstand aging.
The present inventor examines the problems of the background art described above, and aims to provide a reflective substrate for a light-emitting element that has higher heat resistance, excellent light resistance, and high light reflectance.

The inventor has a specific inorganic reflective layer on the substrate surface, and when the inorganic reflective layer has a surface structure derived from a specific OH group, the light reflectance is high, and the sealing resin layer provided on the surface Alternatively, the present invention has been achieved by finding that the surface structure derived from this OH group is excellent in adhesion to the metal wiring layer and has no adverse effect on the withstand voltage, but rather the withstand voltage is improved.

That is, the present invention provides the following.
(1) at least a portion of the valve metal substrate to comprise an inorganic reflective layer, the inorganic reflective layer, Vickers hardness (Hv) 1 GPa or more, the wave number was measured by infrared spectroscopy 3000 cm ^-1 and a wavenumber of 1900 cm ^-1 A reflective substrate for a light emitting device, wherein an OH surface structure absorption coefficient indicated by a difference in absorbance is 0.40 or more.
(2) The reflective substrate for a light-emitting element according to (1), which has an anodized film layer of a valve metal substrate between the valve metal substrate and the inorganic reflective layer.
(3) The inorganic reflective layer has at least one inorganic binder selected from the group consisting of aluminum phosphate, aluminum chloride and sodium silicate, a refractive index of 1.5 to 1.8, and an average particle size of 0 (1) The reflective substrate for light emitting elements according to (1) or (2), which contains inorganic particles of 1 μm or more and 5 μm or less.
(4) The reflective substrate for a light-emitting element according to any one of (1) to (3), wherein the inorganic particles are at least one selected from the group consisting of oxides, hydroxides, and inorganic salts. .
(5) The reflective substrate for a light-emitting element according to any one of (1) to (4), wherein the inorganic particles are at least one selected from the group consisting of barium sulfate and aluminum oxide.
(6) Any of (1) to (5), wherein the valve metal is at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. The reflective board | substrate for light emitting elements of any one of Claims 1-3.
(7) The reflective substrate for a light-emitting element according to any one of (1) to (6), wherein the bulb metal base has a thickness of 0.1 to 2 mm.
(8) The reflective substrate for a light-emitting element according to any one of (1) to (7), wherein the bulb metal is aluminum.
(9) The reflective substrate for light-emitting element according to any one of (1) to (8), wherein the tensile strength of the reflective substrate for light-emitting element is 30 MPa to 100 MPa.
(10) The reflective substrate for a light-emitting element according to any one of (1) to (9), wherein the inorganic particles are two or more types.
(11) An inorganic reflective layer having a Vickers hardness (Hv) of 1 GPa or more provided on at least a part of the surface of the valve metal substrate is subjected to a heat steam treatment or a hydrophilization treatment, and a wave number of 3000 cm ⁻¹ measured by infrared spectroscopy. A method for producing a reflective substrate for a light emitting device, wherein an inorganic reflective layer having an OH surface structure absorption coefficient of 0.40 or more, which is indicated by a difference in absorbance at a wave number of 1900 cm ⁻¹ , is formed.
(12) The light emitting device according to (11), wherein the inorganic reflective layer is mixed with an inorganic binder and inorganic particles, applied to the surface of the bubble metal substrate, and fired at a low temperature of 100 ° C. to 300 ° C. A method for manufacturing a reflective substrate for an element.
(13) The method for producing a reflective substrate for a light-emitting element according to (11) or (12), wherein an inorganic reflective layer is formed on the anodized layer after anodizing the surface of the valve metal substrate.
(14) After undergoing the steps described in any one of (11) to (13) above, the following steps (c) and (d) are performed in an arbitrary order, and any of (11) to (13) A method for producing a reflective substrate for a light emitting device according to claim 1:
(C) forming a metal wiring layer for electric signal transmission to the light emitting element and patterning the metal wiring layer;
(D) The process of providing a metal layer in the electrode part corresponded to the part which mounts a light emitting element.
(15) A white light-emitting diode including a blue light-emitting element on the reflective substrate for a light-emitting element according to any one of (1) to (10), and a fluorescent light-emitting body around and / or above the blue light-emitting element apparatus.

The reflective substrate for a light emitting device of the present invention has high heat resistance, excellent light resistance, and high light reflectance. Moreover, it is excellent in adhesiveness with the sealing resin layer and / or metal wiring layer provided on the surface.

FIG. 1A is an enlarged cross-sectional view illustrating an example of a preferred embodiment of the reflective substrate for a light-emitting element of the present invention, and FIG. 1B illustrates another preferred embodiment of the present invention. It is an expanded sectional view. It is a schematic sectional drawing explaining an example of the suitable embodiment of the reflective substrate for light emitting elements of this invention. It is sectional drawing explaining the light-emitting device using another embodiment of the reflective substrate for light emitting elements of this invention. It is the schematic explaining the wiring pattern used for evaluation. It is a chart which shows the measurement result of the light absorbency by infrared spectroscopy.

[Reflective substrate for light emitting element]
The reflective substrate for a light-emitting element of the present invention is a substrate provided with an inorganic reflective layer on at least a part of the surface of the valve metal substrate, and the inorganic reflective layer has a Vickers hardness of 1 GPa or more and is measured by an infrared spectrophotometer. the difference in absorbance at a wavenumber of 3000 cm ^-1 and a wavenumber 1900 cm ^-1 (hereinafter sometimes referred to as OH surface structure absorption coefficient) is a reflective substrate for light-emitting element is 0.40 or more. The Vickers hardness is preferably 1 GPa or more and 10 GPa or less, and the OH surface structure absorption coefficient is 0.40 or more and 0.8 or less.
Next, the reflective substrate for a light emitting device of the present invention will be described with reference to a preferred example shown in FIG.

FIG. 1 is a schematic view showing an example of a preferred embodiment of the reflective substrate for a light emitting device of the present invention.
As shown in FIG. 1 (A), the reflective substrate 30 for a light-emitting element of the present invention has a Vickers hardness of 1 GPa or more on at least a part of the surface of the valve metal substrate 1 and a wave number measured by an infrared spectrophotometer. 3000 cm ^-1 and the difference in absorbance at wave number 1900 cm ^-1 (OH surface structure absorption coefficient) is a reflective substrate for light-emitting device including an inorganic reflective layer 3 is 0.40 or more.
Further, as shown in FIG. 1B, the reflective substrate 30 for a light-emitting element of the present invention has a good withstand voltage of the substrate, and a good adhesion between the inorganic reflective layer and the substrate for the reason that the valve metal base material is used. first insulating layer, such as anodized film layer 2 is provided on at least part of the surface, and Vickers hardness 1GPa or more as an upper layer, and the wave number 3000 cm ^-1 and a wavenumber 1900 cm ^-1 as measured by infrared spectrophotometry A reflective substrate for a light-emitting element including the inorganic reflective layer 3 having a difference in absorbance (OH surface structure absorption coefficient) of 0.40 or more is preferable.

[Inorganic reflective layer]
1) The constituent material of the inorganic reflective layer is an inorganic component and has a Vickers hardness of 1 GPa or more. The Vickers hardness is preferably 1 GPa or more and 10 GPa or less. The Vickers hardness test method calculates the surface area S (mm ² ) from the diagonal length d (mm) of the dent remaining after the diamond indenter is pushed into the material surface and the load is removed. A value that is 0.102 times the value obtained by dividing the test load F (N) by the calculated surface area S (mm ² ) is the Vickers hardness (Hv), and is obtained by the following equation.
Hv = 0.102 (F / S)
2) the difference in absorbance of the surface of the inorganic reflective layer and the wave number 3000 cm ^-1 as measured by an infrared spectrophotometer wavenumber 1900 cm ^-1 is 0.40 or more. Infrared spectroscopy (abbreviated as IR) is a method of obtaining the spectrum by irradiating the substance to be measured with infrared rays and dispersing the transmitted (or reflected) light to know the characteristics of the object. The infrared spectrum is slightly changed depending on the surface structure of the object. From this, it is possible to know the surface structure of a specific substance.
The result of having measured the infrared absorption spectrum of the inorganic reflective layer surface of Example 1 and Comparative Example 3 which are demonstrated later is shown in FIG.
As the result of FIG. 5 shows, the difference in the surface state between Example 1 and Comparative Example 3 is shown in the wave number range of 3000 to 4000 cm ⁻¹ . This wave number range corresponds to the stretching vibration of the OH group caused by water or the like. As an index representing the difference in surface state shown in the wave number range of 3000 to 4000 cm ⁻¹ between Example 1 and Comparative Example 3, the present inventor can indicate the difference in surface state by setting the following OH surface structure absorption coefficient. I discovered that.
[OH surface structure absorption coefficient = [absorbance at a wavenumber of 3000 cm ^-1] - [absorbance at a wavenumber of 1900 cm ^-1]
For example, the following OH surface structure absorption coefficient can be obtained from the measured values shown in FIG. 5 for Example 1 and Comparative Example 3.

The reference example was adjusted under the following conditions.
Reference example: 1 g of alumina (AL-160SG-3) powder having a particle size of 0.52 μm and a purity of 99.9% was weighed with a hand press device with a load of 1 t to form a tablet with a diameter of 20 mm. Sintered at 2 ° C. for 2 hours.
The inorganic reflective layer of the present invention is not particularly limited as long as it satisfies the above conditions 1) and 2) and the constituent material is an inorganic component. It is preferable not to include an organic component. Since the inorganic reflective layer is an inorganic material, it has high heat resistance and light resistance and is resistant to aging.

The inorganic reflective layer is provided on the valve metal substrate in the reflective substrate for a light emitting device of the present invention. A substrate having an insulating layer on the metal base is preferred for the reason that the insulating properties are better. Specifically, the anodized film layer 2 and the inorganic reflective layer 3 may be provided on a part of the valve metal substrate 1, or only the anodized film layer 2 may be present. This is because the required positions of the insulating layer, which is an anodized film layer, and the inorganic reflective layer differ depending on the shape of the element to be mounted and the position of the wiring, and it is necessary to arrange them in various designs.

In the present invention, the inorganic reflective layer has a thickness of 10 μm or more, preferably 10 to 60 μm, and more preferably 20 to 50 μm.
When the thickness of the inorganic reflective layer is 10 μm or more, the withstand voltage is good. Further, when the thickness of the inorganic reflective layer is 60 μm or less, flexibility is maintained and processability, handleability and the like are improved.
The thickness of the valve metal base plate used in the present invention is preferably 0.1 to 2.0 mm. In particular, the thickness of the aluminum plate is about 0.1 to 2.0 mm, preferably 0.15 to 1.5 mm, and more preferably 0.2 to 1.0 mm. This thickness can be appropriately changed according to the user's wishes or the like.
When an anodized film layer is provided on the valve metal substrate, the thickness of the anodized film layer is preferably 1 to 200 μm. If it is less than 1 μm, the withstand voltage is poor and the withstand voltage is lowered. On the other hand, if it exceeds 200 μm, a large amount of electric power is required for production, which is economically disadvantageous. The thickness of the anodized film layer is preferably 10 μm or more, and more preferably 20 μm or more.

Here, the measuring method of the film thickness of the anodized film layer or the inorganic reflective layer is as follows.
First, a fracture surface produced by bending a substrate provided with an anodized film layer or an inorganic reflective layer is observed and photographed with an ultra-high resolution scanning electron microscope (for example, S-4000, manufactured by Hitachi, Ltd.). Note that the observation magnification is appropriately adjusted depending on the film thickness and the like. Specifically, the magnification is preferably 100 to 10,000 times. Moreover, the observation range shall observe a part with a cross-sectional length of 100 μm or more.

Next, regarding the porous portion of the image data (photograph) obtained by the above method, the thickness of the thickest portion in the observation range is defined as the thickness of the inorganic reflective layer.

<Surface characteristics of inorganic reflective layer>
In order to verify the relationship between the OH surface structure absorption coefficient and the surface structure of the inorganic reflective layer, only 1600 alumina particles used in Example 1, Comparative Example 3 and Example 1 in which the OH surface structure absorption coefficient was measured as described above were used. A surface (reference example) obtained by sintering at 2 ° C. for 2 hours was subjected to thermogravimetric analysis at 100 ° C. to 500 ° C. Using TGA Q500 (manufactured by TA Instruments Japan Co., Ltd.), the measurement was performed at a temperature rising rate of 5 ° C./min. Table 2 below shows values normalized with the mass after thermogravimetric decrease at 300 ° C. as an initial value of 100%. As shown in the results of Table 2, it was confirmed that in the surface structure considered to have many OH groups, the weight loss by thermogravimetric analysis due to loss of surface moisture was large.

<Preferable inorganic reflective layer>
A suitable inorganic reflective layer is an aggregate composed of a large number of inorganic particles containing inorganic particles and an inorganic binder and partially bound to each other by the inorganic binder. It is the inorganic reflective layer being processed. This will be specifically described below.
(Inorganic binder)
In the present invention, aluminum phosphate, aluminum chloride, or sodium silicate is used as a binder for specific inorganic particles. A mixture of two or more of these may be used.
The inorganic binder is a substance that forms inorganic reflection layers by bonding inorganic particles described later by low-temperature firing. The following can be illustrated in detail.
(Aluminum phosphate)
Examples of the aluminum phosphate include aluminum metaphosphate, aluminum orthophosphate, and aluminum polyphosphate.
(Aluminum chloride)
Examples of the aluminum chloride include aluminum chloride, anhydrous aluminum chloride, aluminum chloride hexahydrate, and polyaluminum chloride (a polymer of basic aluminum chloride formed by dissolving aluminum hydroxide in hydrochloric acid).
(Sodium silicate)
The above-mentioned sodium silicate is also called sodium silicate or water glass, and Na ₂ SiO _3, which is a sodium salt of metasilicate, is commonly used. In addition, Na ₄ SiO ₄ , Na ₂ Si ₂ O ₅ , Na ₂ Si ₄ O ₉ or the like can also be used. The sodium salt of metasilicic acid can be obtained by melting silicon dioxide with sodium carbonate or sodium hydroxide.

(Inorganic binder precursor)
The inorganic binder can be obtained by reacting an inorganic binder precursor in the presence of water.
Inorganic binder precursors include inorganic acids such as phosphoric acid, hydrochloric acid, sulfuric acid, aluminum, and aluminum compounds such as aluminum oxide, aluminum sulfate, aluminum hydroxide, aluminum chloride, aluminum phosphate, and mixtures thereof. It is done. If neutralization of the reactant is necessary, sodium hydroxide solution is used. The aluminum compound may be produced by reacting each raw material as an inorganic binder precursor.
Of the above aluminum salts, it is preferable to add both aluminum hydroxide and aluminum chloride to the inorganic binder precursor, and the amount of aluminum chloride is 5% by mass to 10% by mass with respect to the amount of aluminum hydroxide. It is preferable that Aluminum chloride is considered to have a role of catalytically promoting the reaction between aluminum hydroxide and phosphoric acid, and the amount is preferably in the above range. In addition, when aluminum chloride and hydrochloric acid are used and an aluminum phosphate precursor is not used, polyaluminum chloride, which is an inorganic binder, is not colored, so that the light reflectance is high.
A phosphate compound may be used instead of or together with aluminum phosphate, and the phosphate compound is not particularly limited as long as it is insoluble in water. Specific examples include magnesium phosphate, calcium phosphate, zinc phosphate, barium phosphate, aluminum phosphate, gallium phosphate, lanthanum phosphate, titanium phosphate, and zirconium phosphate. Aluminum phosphate is preferable, and when mixed with other phosphates, 50% by mass or more is preferably aluminum phosphate.
When sodium silicate is used, it is dissolved in water, heated and adjusted to a viscosity suitable for water glass, and used as an inorganic binder precursor.
These inorganic binder precursors can be mixed and used in any combination so as to produce the desired inorganic binder.

(Inorganic particles)
In the present invention, the inorganic particles are not particularly limited. For example, conventionally known metal oxides, metal hydroxides, carbonates, sulfates, and the like can be used, and among these, metal oxides are preferably used. .
Specific examples of the inorganic particles include metal oxides such as aluminum oxide (alumina), magnesium oxide, yttrium oxide, titanium oxide, zinc oxide, silicon dioxide, and zirconium oxide; aluminum hydroxide, calcium hydroxide, Hydroxides such as magnesium hydroxide; calcium carbonate (light calcium carbonate, heavy calcium carbonate, ultrafine calcium carbonate, etc.), carbonates such as barium carbonate, magnesium carbonate, strontium carbonate; sulfates such as calcium sulfate and barium sulfate Other examples include calcium carbonate, calcite, marble, gypsum, kaolin clay, calcined clay, talc, sericite, optical glass, glass beads, and the like.
Among these, aluminum oxide, silicon dioxide, aluminum hydroxide, and barium sulfate are preferable because of their good affinity with the inorganic binder described later. More preferred is aluminum oxide.

The inorganic particles used in a suitable inorganic reflective layer have a refractive index of 1.5 or more and 1.8 or less, preferably 1.55 or more and 1.75 or less. When the refractive index is within this range, the obtained inorganic reflective layer has a high reflectance. This reason is considered to be due to a difference in reflectance from air.
The average particle diameter of the inorganic particles is preferably 0.1 μm or more and 5 μm or less. More preferably, it is 0.5-2 μm, and still more preferably 0.5-1.5 μm. When inorganic particles having an average particle diameter in this range are used, it is considered that appropriate voids can be secured between the particles and adhesion with the anodized film layer can be obtained. When the average particle size is less than 0.1 μm, the reflectance is inferior, and when the particle size is more than 6 μm, the adhesion with the anodized film layer may be inferior. Here, the average particle diameter is, for example, a 50% cumulative volume diameter (D50) measured using a laser diffraction / scattering method (laser diffraction / scattering particle size distribution measuring device, Partica LA-910, manufactured by Horiba, Ltd.). Say.
In the process of manufacturing the so-called ceramic layer by binding inorganic particles by high-temperature sintering such as 1000 ° C. or higher in the prior art, it is necessary to control the progress of high-temperature sintering in order to secure specific voids in the layer. is there. On the other hand, the preferred inorganic reflective layer of the present invention does not perform high-temperature sintering by heat drying at a low temperature, so the average particle size of the inorganic particles as the raw material determines the porosity and surface hardness of the inorganic reflective layer, thus affecting the reflectance. It becomes an important factor to do. It was binding the inorganic particles in the high-temperature sintering, such as 1000 ° C. or higher in the prior art, so-called ceramic layer, OH surface structure which is the difference in absorbance of the infrared wave number 3000 cm ^-1 was determined by spectroscopy and the wave number 1900 cm ^-1 Absorption coefficient is less than 0.10.

Although it does not limit as said inorganic particle, For example, the following inorganic particles can be illustrated.
Aluminum oxide (alumina) (refractive index n = 1.65 to 1.76, hereinafter the number in parentheses is the refractive index), aluminum hydroxide (1.58 to 1.65 to 1.76), hydroxide Calcium (1.57 to 1.6), calcium carbonate (1.58), calcite (1.61), calcium carbonate (1.61), light calcium carbonate (1.59), heavy calcium carbonate (1. 56), ultrafine calcium carbonate (1.57), gypsum (1.55), calcium sulfate (1.59), marble (1.57), barium sulfate (1.64), barium carbonate (1.6) , Magnesium oxide (1.72), magnesium carbonate (1.52), magnesium hydroxide (1.58), strontium carbonate (1.52), kaolin clay (1.56), calcined clay (1.62), talc 1.57), sericite (1.57), optical glass (1.51 to 1.64), glass beads (1.51). The material of the particles to be used only needs to satisfy the refractive index in the above range, and since there is no step of sintering, various inorganic salts can be used without being limited to oxides.

Further, two or more kinds of particles or two or more kinds of particles having an average particle diameter may be mixed and used as long as the above characteristics are satisfied. By combining particles of different particle diameters or different materials, it is possible to improve the film strength and the adhesion strength with the substrate.
Furthermore, the effect of smoothing the surface by improving the properties of the coated surface can be expected.

Further, the shape of the inorganic particles is not particularly limited, and for example, spherical, polyhedral (for example, icosahedron, dodecahedron, etc.), cubic, tetrahedral, and uneven or convex protrusions on the surface. Any of a plurality of shapes (hereinafter, also referred to as “compete shape”), a plate shape, a needle shape, or the like may be used.
Among these, spherical, polyhedral, cubic, tetrahedral, and complex shapes are preferred for the reason of excellent heat insulation, and spherical is more preferred for reasons of easy availability and excellent heat insulation.

<Inorganic reflective layer>
The preferred inorganic reflective layer exemplified above is preferably 20 g / m ² to 500 g / m ^{2 in} terms of mass per unit area after heat drying. Within this range, the air gap is left in the interior, so light transmission is suppressed and the reflectance is high. By using the specific inorganic binder described above, high temperature sintering is unnecessary, and an inorganic reflective layer can be produced at a lower cost. The inorganic reflective layer is an inorganic material and is resistant to aging. Furthermore, it reacts with the anodized film of the substrate when forming the reflective layer, and it is possible to ensure adhesion with the substrate.
The amount of inorganic particles in a suitable inorganic reflective layer and the amount of at least one inorganic binder selected from the group consisting of aluminum phosphate, aluminum chloride, and sodium silicate are based on 100 parts by mass of the inorganic particles. The inorganic binder is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass.
A suitable inorganic reflective layer may contain other compounds in addition to the inorganic particles and the inorganic binder. Examples of other compounds include dispersants, reaction accelerators, and the like, and these and the above inorganic particles, inorganic binder precursors, reaction products of inorganic particles and inorganic binders, and the like. It is done.

<The manufacturing method of a suitable inorganic reflection layer>
The method for producing a suitable inorganic reflective layer described above is not particularly limited, but an inorganic binder and / or an inorganic binder precursor and inorganic particles are mixed as a binder liquid described below, and this mixed liquid is mixed. It is preferable to apply a predetermined amount on the anodized film layer using a coater whose film thickness can be adjusted, and then heat treatment (low temperature firing) at 100 to 300 ° C. for 10 to 60 minutes.
The coating method is not particularly limited, and various methods can be used. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. it can.
When the aqueous dispersion of the inorganic binder precursor and the inorganic particles is adjusted with a stoichiometric composition ratio according to the reaction formula, the reaction proceeds and the viscosity of the liquid increases rapidly. In order to avoid such a phenomenon and form an inorganic reflective layer stably, it is desirable to add some water in advance. In addition, it is not desirable that phosphate groups remain in the anodized film layer because it may cause corrosion of the substrate or deterioration of the LED sealing material. Therefore, it is desirable to prescribe a slightly excessive amount of components other than phosphoric acid with respect to the stoichiometric ratio.
The formation of aluminum phosphate, aluminum chloride, or sodium silicate in the heat-dried film can be easily confirmed by analyzing the film surface with an infrared spectrophotometer.

Alternatively, the inorganic reflective layer can be made to have two or more layers by adjusting two or more kinds of binder liquids having different compositions and sequentially applying the binder liquid onto the anodized film. By combining two or more inorganic reflective layers, it is possible to improve the strength of the inorganic reflective layer and the strength of adhesion to the substrate. Furthermore, the effect of smoothing the surface by improving the properties of the coated surface can be expected.
When the inorganic reflective layer has two or more layers, in the present invention, if the inorganic reflective layer that is the outermost surface has a Vickers hardness of 1 GPa or more and an OH surface structure absorption coefficient of 0.40 or more, the other inorganic reflective layers are Inorganic reflective layers other than this requirement can also be used. Preferably, each of the two or more inorganic reflective layers has a Vickers hardness of 1 GPa or more and 10 GPa or less, and an OH surface structure absorption coefficient of 0.40 or more and 0.80 or less.

(Low temperature firing)
By the above-mentioned low-temperature firing, the reaction proceeds and the inorganic particles are bound by an inorganic binder that is generated by the reaction.
The low-temperature firing temperature is 100 ° C. to 300 ° C., preferably 150 ° C. to 300 ° C., and more preferably 180 ° C. to 250 ° C.
If it is less than 100 ° C., moisture removal is not suitable, and if it exceeds 300 ° C., the strength of the aluminum substrate changes, which is not desirable. In addition, a temperature of 150 ° C. or higher is desirable for proceeding and binding the reaction between the inorganic binder precursors, and 180 ° C. or higher for completely removing the adsorbed water remaining in the obtained inorganic binder. It is desirable that When the treatment is performed for a long time at a temperature exceeding 250 ° C., the strength of the valve metal base material is changed.
The firing time is 10 minutes to 60 minutes, more preferably 20 minutes to 40 minutes. In a short time, the progress of the reaction is insufficient, and when the time is long, the strength of the valve metal substrate, particularly the aluminum metal substrate, changes in relation to the firing temperature. If it is more than 60 minutes, it is not desirable in terms of production cost. For this reason, the firing time is most preferably 20 minutes to 40 minutes.
The surface hardness of the inorganic reflective layer obtained by firing at such a low temperature varies depending on the binding treatment conditions, the particle size used, etc., but in order to obtain high hardness, it is important to select the particle size together with the firing temperature. is there. The average particle diameter of the inorganic particles is preferably 0.1 μm or more and 5 μm or less. When the particles having an average particle diameter in this range are fired at a temperature in the above range, the surface hardness of the inorganic reflective layer obtained is appropriate.
Since the binder liquid is a liquid containing water, a drying step may be performed after the coating and before the low-temperature baking treatment. Drying is performed at a temperature of 100 ° C. or lower which does not cause a formation reaction of an inorganic binder such as aluminum phosphate or a binding reaction of inorganic particles.

<Post-processing>
The surface of the inorganic reflective layer of the present invention can have an OH surface structure absorption coefficient of 0.40 or more depending on the combination of constituent materials and manufacturing methods. Moreover, it is preferable that the suitable inorganic reflective layer illustrated above is post-processed on the surface after a low-temperature baking process. A preferable post-treatment is exemplified by the following heating steam treatment or hydrophilization treatment, but is not limited to these, and the surface of the above-mentioned suitable inorganic reflective layer which is equivalent to these is measured by infrared spectroscopy. In this treatment, the obtained OH surface structure absorption coefficient is 0.40 or more.
According to the knowledge of the present inventor, the inorganic reflective layer of the present invention is subjected to post-treatment, so that the presence of the hydrate of alumina hydrate or aluminum phosphate or the like causes the reflective substrate for light emitting device of the present invention. The withstand voltage can be improved without impairing the thermal conductivity and reflectance. This was a remarkable and unexpected effect.

(Heated steam treatment)
In the present invention, it is preferable that a suitable inorganic reflective layer is subjected to a heat steam treatment after the low temperature firing treatment. The heated steam treatment is a treatment including boiling water treatment, hot water treatment, steam treatment, and the like based on temperature and pressure conditions.
The water used may be any of ion exchange water, distilled water, natural water, tap water, etc., but ion exchange water and distilled water are preferred. Further, as an accelerator for these waters and a sequestering agent for metal ions in the water, an organic solvent, an amine compound, an organic acid, phosphorus or boron oxyacid salt, or the like may be used alone or in combination. Further, the water used may contain ions of alkali metal alkaline earth metal such as lithium, sodium or magnesium.
The surface treatment is preferably carried out continuously using water vapor, and the temperature for the water vapor treatment is about 80 ° C. to 200 ° C., preferably about 90 ° C. to 120 ° C. The treatment time is 3 seconds to 30 minutes, preferably 5 seconds to 10 minutes. The hydrogen ion concentration is suitably about 2 to 11, preferably about 3 to 10. About 1 to 15 kg / cm ² (absolute pressure) is appropriate as the pressure when treating with pressurized steam, and preferably about 1 to 5 kg / cm ² is preferred.
Industrially, the temperature of water in a water tank provided in the processing chamber is heated, whereby the temperature in the processing chamber is set to 80 ° C. or more and 105 ° C. or less, and the processing chamber pressure is maintained at −50 to 300 mmAq with respect to normal pressure. Alternatively, a method may be used in which the inorganic reflective layer requiring heating steam treatment is passed through the state.

(Hydrophilic treatment)
In the present invention, a suitable inorganic reflective layer is preferably subjected to a hydrophilization treatment after the low-temperature baking treatment.
Specific examples of the hydrophilic treatment method include a method of immersing in an aqueous solution of an alkali metal silicate.

Here, the hydrophilization treatment using an aqueous solution of alkali metal silicate is performed according to the method and procedure described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be carried out.

Specific examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate.
The aqueous solution of the alkali metal silicate may further contain sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.

Furthermore, the aqueous solution of the alkali metal silicate may further contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt.
Here, specific examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; Borate; and the like.
Specific examples of the Group 4 (Group IVA) metal salt include, for example, titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, and chloride oxidation. Zirconium, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride and the like can be mentioned.
These alkaline earth metal salts and Group 4 (Group IVA) metal salts may be used alone or in combination of two or more.
In the hydrophilization treatment, when an aqueous solution of the alkali metal silicate is used, the aqueous solution of the alkali metal silicate is a ratio of silicon oxide SiO ₂ and alkali metal oxide M ₂ O, which are components of the silicate ( In general, the protective film thickness can be adjusted by the concentration of [SiO ₂ ] / [M ₂ O]) and the concentration.
Here, as M, sodium and potassium are particularly preferably used.
The molar ratio of [SiO ₂ ] / [M ₂ O] is preferably 0.1 to 5.0, more preferably 0.5 to 3.0. Further, the content of SiO ₂ is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass.

The temperature of the aqueous alkali metal silicate solution is preferably 1 to 70 ° C., more preferably 2 to 50 ° C., and still more preferably 3 to 35 ° C.
Further, the treatment time in the case of using the alkali metal silicate aqueous solution is preferably 5 seconds to 90 minutes, more preferably 8 seconds to 60 minutes, and preferably 12 seconds to 30 minutes. Further preferred.

[Valve metal substrate]
Specific examples of the valve metal include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony.
The anodized film layer of the valve metal is an insulating film having an electrical resistivity (about 10 ¹⁴ Ω · cm) and high heat resistance.
Of these, an anodic oxide film layer of aluminum is preferable because it has good dimensional stability and is relatively inexpensive.
The valve metal substrate may be a single plate used for the reflective substrate of the present invention.
If necessary, the valve metal substrate is laminated on another metal plate such as a steel plate, a glass plate, a ceramic plate, a resin plate, or the like, and provided on the reflective substrate of the present invention. In order to form an anodized film and ensure a withstand voltage, the bubble metal substrate only needs to have a plate-like portion having a thickness of 10 μm or more. When another plate material and a valve metal base material are laminated and used, a laminated plate of a steel plate or metal plate that is flexible and has high heat resistance is preferable.

(Aluminum plate)
A known aluminum plate can be used for the production of the reflective substrate of the present invention. The aluminum plate used in the present invention is a metal whose main component is dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements can also be used.

In this specification, various substrates made of the above-described aluminum or aluminum alloy are collectively referred to as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, copper, manganese, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the content of the foreign elements in the alloy is 10% by mass or less. It is.

Thus, the composition of the aluminum plate used in the present invention is not specified, and the purity of aluminum is not particularly limited, but 1000 series, 3000 series, and 5000 series alloys that are usually used as plate materials are used. it can. However, when used as a reflective substrate for a light emitting device, it is required to have excellent withstand voltage, and it is desirable to reduce particles such as intermetallic compounds in the material as much as possible. If it cannot be avoided under heat treatment conditions, it is also useful to use high purity aluminum of 99.9% or more.
Specifically, conventionally known materials described in Aluminum Handbook 4th edition (1990, published by Light Metal Association), for example, JIS A1050, JIS A1100, JIS A1070, JIS A3004 containing Mn, international registered alloy 3103A, etc. Al-Mn aluminum plates can be used as appropriate. For the purpose of increasing the tensile strength, an Al—Mg alloy or an Al—Mn—Mg alloy (JIS A3005) in which 0.1% by mass or more of magnesium is added to these aluminum alloys can also be used. Furthermore, an Al—Zr alloy or an Al—Si alloy containing Zr or Si can also be used. Furthermore, an Al—Mg—Si based alloy can also be used.

Regarding Al—Mg alloys, Al—Mn alloys, Al—Mn—Mg alloys, Al—Zr alloys, and Al—Mg—Si alloys, paragraphs [0034] to [0038] of International Publication No. WO2010 / 150810. Is described in the publication.

Regarding the method for producing an aluminum alloy into a plate material, DC casting method, continuous casting method, crystal structure of the surface of the aluminum plate, and intermetallic compound of the aluminum plate, paragraphs [0039] to [0050] of International Publication WO2010 / 150810 Are listed.

In the present invention, an aluminum plate as shown above can be used by roughening it by forming irregularities by laminating rolling, transferring or the like in its final rolling step or the like. If the surface of the substrate is roughened in advance, the adhesion between the inorganic reflective layer formed on the substrate and the substrate can be improved after the anodic oxide film layer is formed. Other roughening treatment methods will be described later.

The aluminum plate used in the present invention may be an aluminum web or a sheet-like sheet.

[Method for producing reflective substrate for light emitting element]
<1. Roughening>
When the reflective substrate of the present invention is produced, an anodized film layer may be formed by directly anodizing an aluminum plate degreased by alkali. Further, if the aluminum surface is roughened in advance and anodized, the adhesion between the anodized film layer and the aluminum plate can be improved. Roughening treatment is a method of performing mechanical roughening treatment on an aluminum plate, alkali etching treatment, desmutting treatment with acid, and electrochemical roughening treatment using an electrolytic solution, and mechanical roughening treatment on an aluminum plate. Treatment, alkali etching treatment, desmutting treatment with acid and electrochemical surface roughening treatment using different electrolytes multiple times, alkali etching treatment on aluminum plate, desmutting treatment with acid and electrochemical using electrolyte solution Examples include a method of sequentially performing a surface roughening treatment, a method of applying an alkali etching treatment to an aluminum plate, a desmutting treatment with an acid, and an electrochemical surface roughening treatment using different electrolytes a plurality of times, but the present invention is not limited thereto. Not. In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed.

Among them, although depending on the conditions of other treatments (alkali etching treatment, etc.), in order to form a surface shape on which a large wave structure, a medium wave structure and a small wave structure are superimposed, a mechanical surface roughening treatment and nitric acid are mainly used. Preferred examples include a method of sequentially performing an electrochemical surface roughening treatment using an electrolytic solution and an electrochemical surface roughening treatment using an electrolytic solution mainly composed of hydrochloric acid. In addition, in order to form a surface shape in which a large wave structure and a small wave structure are superimposed, an electrolytic solution mainly composed of hydrochloric acid is used, and only an electrochemical surface roughening process is performed in which the total amount of electricity involved in the anode reaction is increased. Are preferable.
Details of each surface roughening treatment are described in paragraphs [0055] to [0083] of International Publication WO2010 / 150810.

<2. Through-hole processing>
In the reflective substrate for a light-emitting element of the present invention, when mounting the light-emitting element, a through-hole process for appropriately providing a wiring portion and a routing process for forming a chip assuming the final product (to the final product) Processing for individualization) can also be performed. Through-hole processing is drilling to the required location, but the shape of the processed through-hole is the length between multiple layers where wiring is required, and the cross-section is the required wiring in it. The size / shape is not particularly limited as long as it can be secured by insertion, but considering the final chip size and reliable wiring formation, a circular shape is preferable, and the size is from 0.01 mmφ to 2 mmφ is preferable, 0.05 mmφ to 1 mmφ is more preferable, and 0.1 mmφ to 0.8 mmφ is particularly preferable.

(Routing processing)
The routing process is an individual separation process that separates the light-emitting element reflective substrate (hereinafter referred to as a chip) that is individualized into the final product, or a process that makes it easy to separate into chips in advance, and is also referred to as patterning or chip formation. . The routing process includes a process of making a notch penetrating in the thickness direction of the substrate with a device called a router or making a notch so as not to cut in the thickness direction using a dicer.

<3. Firing treatment>
The tensile strength (hereinafter referred to as tensile strength) in the tensile test (tensile speed: 2 mm / min) according to JIS Z2241 of the aluminum plate in the routing processing and through-hole processing described above is that the substrate is a soft substrate such as 100 MPa or less. When the reflective substrate for a light emitting element of the present invention is manufactured, it is desirable that the aluminum plate is fired to soften the aluminum plate after mechanical processing such as routing processing or through-hole processing. Further, if firing is performed after the anodizing treatment, cracks and the like due to the difference in thermal expansion coefficient between the aluminum and the coating may occur, which is not desirable. Therefore, it is desirable to perform a baking treatment for adjusting the strength of the aluminum plate after the machining and before the anodizing treatment. The baking treatment after the machining and before the anodizing treatment is preferably performed at 250 to 400 ° C. for 1 to 120 minutes. When performing the baking treatment after the anodizing treatment, the baking temperature is preferably 200 ° C. to 250 ° C., and the heat treatment is preferably performed for 60 minutes to 300 minutes.

<4. Anodizing>
It is preferable to further anodize the aluminum plate that has been surface-treated and processed as described above. By anodizing treatment, an anodized film layer made of alumina is formed on the surface of the aluminum plate, and a porous or non-porous surface insulating layer is obtained.

The anodizing treatment can be performed by a conventional method. In this case, for example, an anodized film layer can be formed by energizing an aluminum plate as an anode in an aqueous solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less. As the solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, malonic acid, citric acid, tartaric acid, boric acid, etc. alone or in combination A combination of the above can be used.

The conditions of the anodizing treatment cannot be determined unconditionally because they vary depending on the electrolyte used, but generally the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. It is appropriate that ˜60 A / dm ² , voltage 1˜100 V, electrolysis time 15 seconds˜50 minutes, and the anodic oxide film layer amount is adjusted to a desired amount.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied. When direct current is applied to the aluminum plate, the current density is preferably 1 to 60 A / dm ² , and more preferably 5 to 40 A / dm ² . In the case of continuous anodizing treatment, a low current of 5 to 10 A / dm ² is initially introduced so that so-called “burning” does not occur due to current concentration on a part of the aluminum plate. It is preferable to increase the current density to 30 to 50 A / dm ² or more as the current is passed at the density and the anodization process proceeds. When the anodizing treatment is continuously performed, it is preferable that the feeding method to the aluminum plate is performed by a liquid feeding method. The liquid power supply method is an indirect power supply method that does not use a conductor roll, and power is supplied through an electrolytic solution.

The anodized film layer may be porous or nonporous. In the case of being porous, the average pore diameter is about 5 to 1000 nm, and the average pore density is about 1 × 10 ⁶ to 1 × 10 ¹⁰ / mm ² .

The other details of the anodizing treatment are described in paragraphs [0091] to [0094] of International Publication No. WO2010 / 150810.

Aluminum has a very high thermal conductivity and is excellent in heat dissipation. In addition to being superior to other metals, it is possible to provide a withstand voltage by forming an anodized film layer on the surface layer.
A substrate that has been pre-processed into a substrate shape on which an LED is mounted, for example, a hexagonal shape, an octagonal shape, or a through-hole-formed one may be anodized and used as a substrate. You may process after forming an inorganic reflection layer.
The thickness of the anodized film layer is preferably 1 to 200 μm. If the thickness is less than 1 μm, the insulation is poor and the withstand voltage is lowered. On the other hand, if it exceeds 200 μm, a large amount of electric power is required for production, which is economically disadvantageous. The thickness of the anodized film layer is preferably 10 μm or more, and more preferably 20 μm or more.

<5. Formation of inorganic reflective layer>
Furthermore, the above-mentioned inorganic reflective layer is formed only on the portions where light reflection is required by various printing methods such as screen printing on a substrate that has been processed in advance so that it can be disassembled into chips or parts including a plurality of chips. Also good. If the inorganic reflective layer is formed by this method, the raw material used for the inorganic reflective layer can be saved.

(Reflective substrate for light emitting element)
When the reflective substrate for a light-emitting element having the inorganic reflective layer of the present invention described above is not used for reinforcing a core material or the like when using another metal plate as a valve metal substrate alone, The strength is preferably 100 MPa or less, more preferably 30 to 90 MPa, in the tensile strength (hereinafter referred to as tensile strength) in a tensile test according to JIS Z2241 (tensile speed: 2 mm / min). More preferably, it is 40 to 80 MPa. If it is less than this range, the strength as a reflective substrate for a light-emitting element is not sufficient, and if it exceeds this range, the handleability when processing the substrate into a light-emitting device is poor.

(Metal wiring layer)
The reflective substrate for light emitting element of the present invention may further form a metal wiring layer. The metal wiring layer may be provided on the anodized film layer on which the light emitting element is mounted and the inorganic reflective layer, or on the back side opposite to the anodized film layer on which the light emitting element is mounted. The light emitting element mounting surface may be electrically connected through a through hole.
The inorganic reflective layer of the present invention has high adhesion to the metal wiring layer provided thereon. This is because, in the inorganic reflective layer of the present invention, the OH surface structure absorption coefficient measured by infrared spectroscopy is 0.40 or more, so it is considered that hydroxides and hydrates exist on the surface. It is thought that the wettability with the ink which manufactures a wiring layer is high, and the adhesiveness with the inorganic reflection layer of the metal wiring layer obtained is considered high.

The material of the metal wiring layer is not particularly limited as long as it is a material that conducts electricity (hereinafter also referred to as “metal material”). Specific examples thereof include gold (Au), silver (Ag), and copper (Cu ), Aluminum (Al), magnesium (Mg), nickel (Ni) and the like, and these may be used alone or in combination of two or more. Of these, Cu is preferably used because of its low electrical resistance. Note that an Au layer or a Ni / Au layer may be provided on the surface layer of the wiring layer made of Cu from the viewpoint of improving the ease of wire bonding.
The metal wiring layer may have a multilayer structure using these materials. For example, an embodiment in which an Ag layer, a Ni layer, and an Au layer are provided in this order from the bottom layer is preferable.

The thickness of the metal wiring layer may be a desired thickness depending on the purpose and application, but is preferably 0.5 to 1000 μm from the viewpoint of conduction reliability and package compactness, and preferably 1 to 500 μm. More preferred is 5 to 250 μm.

<6. Formation of metal wiring layer>
As a method for forming the metal wiring layer, for example, a metal ink containing the metal material and a liquid component (for example, a solvent, a resin component, etc.) is pattern-printed on the receiving layer by an inkjet printing method, a screen printing method, or the like. Methods and the like.
By such a forming method, a metal wiring layer having a pattern can be easily formed on the surface of the uneven inorganic reflective layer without requiring many steps.

Other metal wiring layer formation methods include, for example, various plating processes such as electrolytic plating, electroless plating, and displacement plating, sputtering, vapor deposition, vacuum pasting of metal foil, and adhesion. Examples thereof include an adhesion treatment with a layer.

The metal wiring layer thus formed is patterned by a known method according to the design of the light emitting element mounting. Further, a metal layer (including solder) is again provided at a place where the light emitting element is actually mounted, and can be appropriately processed so as to be easily connected by thermocompression bonding, flip chip, wire bonding, or the like.
As a suitable metal layer, a metal material such as solder or gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni) is preferable. When the element is mounted, a method of providing Au or Ag via solder or Ni is preferable from the viewpoint of connection reliability.
At this time, if the reflective layer has a low hardness, the wire does not melt well when wire bonding is performed by rubbing the wire to the electrode, and connection failure tends to occur. When the inorganic reflective layer of the present invention was used, the surface hardness was 1 GPa or more, and no connection failure occurred.

If a pattern is formed on an inorganic reflective layer using an ink jet printing method or a screen printing method using a metal ink as a method for forming a metal wiring layer, a metal having a pattern can be easily formed on an uneven surface without requiring many steps. A wiring layer can be formed, and since the anchor effect by the unevenness | corrugation of an inorganic reflection layer is high, it is excellent also in the adhesiveness of a metal wiring layer and an inorganic reflection layer. If combined with electroless plating, a metal layer (including solder) is provided again on the metal wiring layer, so that it is easy to connect between wirings and electrodes with thermocompression bonding, flip chip, wire bonding, etc. The metal wiring layer can be processed appropriately.

[White light emitting device]
FIG. 3 is a schematic view showing a configuration example of the white light emitting device of the present invention.
In the example of FIG. 3, the valve metal substrate has a shape with a recess, and the anodized film layer 2 and the inorganic reflective layer 3 are provided on the surface of the valve metal substrate 11 with a shape having a recess 13. The light emitting element 110 is mounted in the recess 13 on the inorganic reflective layer 3, and the surface opposite to the surface on which the light emitting element 110 is mounted through the anodized film layer 2 of the valve metal substrate 11 is for heat dissipation. The heat sink 18 is provided.
In the white light emitting device 100 shown in FIG. 3, the LED element which is the light emitting element 110 is mounted on the light emitting element reflecting substrate 30 having the electrode for external connection, and the electrode is electrically connected by the wire bonding 19. Yes. The light emitting element 110 is sealed with a resin material 160 including a phosphor (fluorescent particle) 150. In the white light emitting device 100, light having a desired wavelength can be obtained by mixing the light emitted from the LED element and the excitation light from the phosphor 150. When used as a white light-emitting device, a blue light-emitting LED element is used as the LED element, sealed with a resin containing a phosphor (fluorescent particle) 150 such as YAG (yttrium aluminum garnet), and the blue color from the LED element. Pseudo white light is emitted to the light emitting surface side by the color mixture of the light emission and the yellow region excitation light from the phosphor (fluorescent particle) 150.
In the LED element, a light emitting layer using a semiconductor such as GaAlN, ZnS, ZnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN can be used. Examples of the semiconductor structure include a homostructure, a heterostructure, or a double heterostructure having a MIS junction, a PIN junction, or a PN junction. The emission wavelength can be variously selected from ultraviolet light to infrared light depending on the semiconductor material and the degree of mixed crystal.

The white light emitting device 100 of the present invention is provided with the anodized film layer 2 and the inorganic reflective layer 3 that are excellent in film strength and adhesion to the substrate on the valve metal substrate 11 as the reflective substrate 30, The light reflectance of the reflective layer is also high.
The inorganic reflective layer of the present invention has high adhesion with a resin layer containing a phosphor provided thereon. This is because, in the inorganic reflective layer of the present invention, the OH surface structure absorption coefficient measured by infrared spectroscopy is 0.40 or more, so it is considered that hydroxides and hydrates exist on the surface. It is considered that the adhesiveness with the resin layer is high.
Reflection for light-emitting elements of the present invention having high light reflection characteristics without high-temperature sintering by expanding the use range of LED elements to various fields such as indoor and outdoor lighting, automobile headlights, backlight units of display devices, etc. The substrate is useful.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

(Examples 1 to 23 and Comparative Examples 1 to 9)
<1. Preparation of base inorganic reflective layer coating solution>
Binders and water shown in Tables 3 and 4 were mixed, stirred and mixed to prepare a binder liquid for an inorganic reflective layer.
First, the formulation of the binder liquid will be described.
<Binder liquid (aluminum phosphate)>
The binder liquid described as aluminum phosphate in the binder types of Tables 3 and 4 is as follows.
Phosphoric acid 85% (Wako Pure Chemical Industries) 48g
Aluminum hydroxide (Wako Pure Chemical Industries) 11g
Water 41g
Total 100g

<Binder liquid (aluminum chloride)>
The binder liquid described as aluminum chloride in the binder types of Tables 3 and 4 is as follows.
Hydrochloric acid 35% (made by Wako Pure Chemical Industries) 31.7g
7.4g of aluminum hydroxide
60.9g of water
Total 100g
<Binder liquid (sodium silicate)>
The binder liquid described as sodium silicate in the binder types of Tables 3 and 4 is as follows.
Sodium silicate (No. 3 sodium silicate: Fuji Chemical Co., Ltd.) 80g
20g of water
Total 100g
<Binder liquid (aluminum phosphate / aluminum chloride)>
The binder liquids described as aluminum phosphate / aluminum chloride in the binder types in Tables 3 and 4 are as follows.
Phosphoric acid 85% (Wako Pure Chemical Industries) 48g
Aluminum hydroxide (Wako Pure Chemical Industries) 11g
Aluminum chloride (Wako Pure Chemical Industries) 0.8g
Water 40.2g
Total 100g
<Binder liquid (epoxy resin), (PDMS)>
The binder liquids described as epoxy resin and PDMS in the binder types shown in Tables 3 and 4 are as follows.
As the binder liquid (epoxy resin), an epoxy resin (BPA type epoxy resin YD-128 manufactured by Nippon Steel Chemical Co., Ltd.) was used, and as the binder liquid (PDMS), polydimethylsiloxane: manufactured by Wako Pure Chemical Industries, Ltd. was used.

The following inorganic particles shown in Tables 3 and 4 were added at a ratio of 100 g to 100 g of the binder liquid to prepare an inorganic reflective layer coating liquid.
1) Alumina The alumina particles used are described below. Tables 3 and 4 list the refractive index, average particle diameter, type, and composition.
AL-160SG-3 made by Showa Denko Co., Ltd. Average particle size 0.52μm Purity 99.9% is used, and the one with a small average particle size is pulverized with zirconia beads using a ball mill and using a particle size measuring device. Those having a desired average particle diameter were taken out and used.
1-1) AL-160SG-3 was used as it was without crushing.
1-2) A42-2 manufactured by Showa Denko KK Average particle size 4.7 μm Purity 99.57% was used.
1-3) CB-P10 manufactured by Showa Denko Co., Ltd. An average particle diameter of 10 μm and a purity of 99.64% and an average particle diameter of 8 μm and a purity of 99.64% were used.
1-4) NanoTek alumina powder (average particle size: 0.03 μm) manufactured by CI Kasei Co., Ltd. was used.
2) Calcium hydroxide, manufactured by Ube Materials Co., Ltd., CSH, purity 99.99%, average particle diameter 1 μm was used.
3) Barium sulfate The barium sulfate particles used are described below.
3-1) B-30 manufactured by Toshin Kasei Co., Ltd., purity 94%, average particle size 0.3 μm was used.
3-2) W-1 manufactured by Takehara Chemical Industry Co., Ltd., with an average particle size of 1.5 μm was used.
As a mixture of two different kinds of inorganic particles, a mixture having an average particle size shown in the table was used. The mixing ratio was set such that particles having an average particle diameter of 0.01 μm were 20% by mass in the total mass of the particles.

<2. Preparation of substrate>
As the substrate, aluminum plates (thickness 0.2 mm, 0.8 mm, 1.5 mm, 4 mm 1050 material, manufactured by Nippon Light Metal Co., Ltd.) were used, and the following processing was performed to prepare substrates A to C, respectively.
Substrate A: Alkaline degreasing treatment and desmutting treatment were performed on the aluminum plate. Tables 3 and 4 describe metal species Al, anodized film, and nothing.
Substrate B: The above aluminum plate was subjected to alkali degreasing treatment and anodizing treatment. Tables 3 and 4 describe the metal species Al, anodized film, and existence.
Substrate C: The above aluminum plate was subjected to alkali degreasing treatment, roughening treatment and anodizing treatment. Tables 3 and 4 describe the metal species Al (roughening), anodized film, and existence.
Substrate Ti: In Example 15, a metal seed titanium plate (manufactured by Soekawa Richemical Co., Ltd.) and a plate thickness of 0.8 mm were used, and an anodized film having a thickness of 20 μm was prepared. Tables 3 and 4 describe the metal species Ti, anodized film, and existence.

(1) Processing conditions for substrate A a. Degreasing treatment in alkaline aqueous solution An aqueous solution having a sodium hydroxide concentration of 27% by mass, an aluminum ion concentration of 6.5% by mass, and a temperature of 70 ° C. was sprayed onto an aluminum plate for 20 seconds. Thereafter, the liquid was drained with a nip roller, and further, a water washing treatment described later was performed, and then the liquid was drained with a nip roller.
The water washing treatment was carried out using an apparatus for washing with a free-falling curtain-like liquid film, and further washed with water for 5 seconds using a spray tube having a structure having spray tips with fan-shaped spreading at 80 mm intervals. .
b. Desmutting treatment in acidic aqueous solution After the degreasing treatment, desmutting treatment was performed. The acidic aqueous solution used for the desmut treatment was a 1% by mass sulfuric acid aqueous solution, which was sprayed from a spray tube at a liquid temperature of 35 ° C. for 5 seconds. Thereafter, the liquid was drained with a nip roller and subsequently washed with water using the above-described apparatus.

(2) Processing conditions for substrate B The substrate prepared in the same manner as substrate A was used as an anode, and anodization was performed using an anodizing apparatus. As the electrolytic solution, an electrolytic solution (temperature 20 ° C.) in which aluminum sulfate was dissolved in a 70 g / L sulfuric acid aqueous solution and the aluminum ion concentration was 5 g / L was used. In the anodizing treatment, electrolysis was performed at a constant voltage so that the voltage during the anodic reaction of the aluminum plate was 25V. The final anodic oxide film layer thickness was set to 20 μm.
Thereafter, the liquid was drained by a nip roller, and further, the water was washed using a spray tube having the same structure as that used in the water washing process, and then the liquid was drained by a nip roller.

(3) Processing conditions for substrate C A substrate prepared in the same manner as substrate A was roughened under the following conditions, and then anodized under the same conditions as substrate B using an anodizing apparatus. .
a. Surface roughening treatment method An electrochemical surface roughening treatment was performed using an electrolytic solution having a nitric acid concentration of 1% by mass, an aluminum ion concentration of 5 g / L, and a liquid temperature of 60 ° C. The aluminum ion concentration was adjusted by adding aluminum nitrate. The ammonium ion concentration was 70 mg / L.
Current is controlled by PWM (Pulse Width Modulation) control using IGBT (Insulated Gate Bipolar Transistor) element, using a power source that generates an alternating current of arbitrary waveform, and using a counter electrode made of carbon to load AC to the sample and counter electrode An electrochemical roughening treatment was performed.
A trapezoidal wave was used as the alternating current, the frequency was 60 Hz, the time TP until the current value reached the peak from zero, 0.1 sec, and the positive / negative current ratio was set to 0.5. The amount of positive current electricity flowing through the sample was adjusted to 200 C / dm ² .
Thereafter, the liquid was drained by a nip roller, and further, the water was washed using a spray tube having the same structure as that used in the water washing process, and then the liquid was drained by a nip roller.
After the electrolytic treatment, an aqueous solution having a sodium hydroxide concentration of 27% by mass, an aluminum ion concentration of 6.5% by mass, and a temperature of 70 ° C. was sprayed onto the aluminum plate from a spray tube for 20 seconds.
Thereafter, the liquid was drained with a nip roller, and further, a water washing treatment described later was performed, and then the liquid was drained with a nip roller. The water washing treatment was carried out with water using an apparatus for washing with a free-fall curtain-like liquid film, and further with water for 5 seconds using a spray tube having a structure in which fan tips were spread at intervals of 80 mm. . Further, after the above degreasing treatment, a desmut treatment was performed. The acidic aqueous solution used for the desmut treatment was a 1% by mass sulfuric acid aqueous solution, which was sprayed from a spray tube at a liquid temperature of 35 ° C. for 5 seconds. Then, the liquid was drained with a nip roller. After this treatment, anodization treatment was performed under the same conditions as those for the substrate B.

<3. Formation of reflective layer on substrate>
The adjusted coating solution was applied onto the substrate by a coater capable of adjusting the coating film thickness. Then, it put into the oven heated up to the temperature of Table 3, 4, and heat-dried for 5 minutes. The amount of the inorganic reflective layer after drying, Example ranged from ^{20g / m 2 ~ 500g / m} 2 with Comparative Example.
In Comparative Examples 5 and 6, the inorganic particles listed in Table 4 were applied to the anodized film layer using epoxy resin and PDMS, respectively, and dried. In Comparative Example 7, no inorganic reflective layer was formed.
In Table 4, “-” is described when a member is not used, measured, or not processed.

<4. Post-processing>
The post-treatment shown in Tables 5 and 6 below was performed on the substrate with a reflective layer obtained above.
(1) Heated steam treatment The substrate with a reflective layer was treated with 110 ° C. steam for 1 minute.
(2) Hydrophilization treatment The substrate with a reflective layer was immersed in a 2.5% by mass sodium silicate solution and dried at 180 ° C. for 5 minutes for hydrophilic treatment.

<5. Evaluation method>
The obtained substrate with a reflective layer was evaluated under the following conditions, and the results are shown in Tables 3-6.
(1) OH surface structure absorption coefficient Fourier transform infrared spectroscopy (FT-IR) was used absorbance (FT-IR) was measured, the difference of the OH surface structure absorption coefficient of absorbance at a wavenumber of 3000 cm ^-1 and a wavenumber 1900 cm ^-1 Calculated as FT-IR 8400S manufactured by Shimadzu Corporation is equipped with optional parts that allow reflection measurement (Foundation Siries 0070-154 manufactured by Thermo Spectra-Tech), and the absorbance was measured from the difference from reflected light by applying IR light to the substrate surface. .
(2) Hardness and strength The Vickers hardness of the reflective substrate for a light emitting device having an inorganic reflective layer on the substrate was measured with a Vickers hardness tester (model AVK-CO, manufactured by Mitutoyo Corporation). The tensile strength was measured by a tensile test according to JIS Z2241 (tensile speed: 2 mm / min). The results are shown in Tables 5 and 6.

(3) Adhesiveness between substrate and inorganic reflective layer A substrate that was cut into a 30 mm square shape with a push cutter and was not peeled off was dropped onto a concrete ground from a height of 3 m, and the following evaluation was made. The results are shown in Tables 5 and 6 below.
AA: not peeled A: partly peeled B: peeled part was considerably seen C: peeled D: peeled off when cut with a push cutter.

(4) Withstand voltage The withstand voltage was evaluated by measuring the withstand voltage (DC) using an insulation resistance tester (TOS9200, manufactured by Kikusui).
Specifically, the produced reflective substrate was placed on a metal base material (aluminum plate), measured by pressing the probe against the inorganic reflective layer side, and the withstand voltage was measured.

(5) Reflectance Using the reflection densitometer (CM2600D, manufactured by Konica Minolta Co., Ltd.), the total reflectance (total average of SPIN mode) of 400 to 700 nm was measured for the produced substrate.

(6) Thermal conductivity The obtained insulating substrate was measured for thermal conductivity according to the t1 / 2 method using a TC-9000 / laser flash type thermal diffusivity measuring apparatus manufactured by ULVAC-RIKO. The results are shown in Tables 5 and 6.

[Production of metal wiring layer]
A diluted solution of silver nanoparticle ink (XA-436, manufactured by Fujikura Chemical Co., Ltd.) was applied to the surface of the obtained reflective substrate using an ink jet apparatus (DMP-2831, manufactured by Fuji Film Co., Ltd.) of the metal wiring layer 20 shown in FIG. Ag wiring (wiring width: 100 μm) was formed by droplet ejection.
Next, plating was performed with a plating solution containing nickel to form an Ag—Ni wiring.
Finally, plating was performed with a plating solution containing gold to form an Ag—Ni—gold wiring. The thickness of each layer was Ag (20 μm), Ni (4 μm), Au (0.4 μm).
Next, the light emitting element (LED) 10 was mounted on the surface of the reflective substrate 30 of the example and the comparative example, and was electrically connected to the metal wiring layer 20 by wire bonding.

(7) Adhesiveness between wiring and inorganic reflection layer For each of the produced wiring boards, wiring adhesiveness was evaluated according to the following criteria.
A: A soldering iron heated to 350 ° C is pressed against the wiring part for 1 minute, and there is no peeling of the wiring when the iron is released. B: A soldering iron heated to 350 ° C is pressed against the wiring part for 1 minute. When the soldering iron was released, the wiring was scratched. C: Soldering iron heated to 350 ° C was pressed against the wiring part for 1 minute. When the iron was released, the wiring peeled off or “floated”. What happened

[Evaluation of Examples and Comparative Examples]
Examples 1 to 22 have a high OH group surface structure absorption coefficient, excellent withstand voltage and thermal conductivity, excellent adhesion between the substrate and the inorganic reflective layer, and excellent adhesion between the wiring and the inorganic reflective layer. Yes.
In Example 2, since the aluminum substrate is roughened and anodized, the adhesion between the substrate and the inorganic reflective layer is particularly excellent.
Since the substrates of Examples 1, 2, 5 to 12, and 14 to 22 have an anodized film, the adhesion between the substrate and the inorganic reflective layer is excellent.
In Comparative Example 1, the hardness of the inorganic reflective layer is low, and the handleability during processing is poor. Heat-treated with steam and has a high OH-based surface structure absorption coefficient and good withstand voltage and thermal conductivity. However, since the average particle diameter of the inorganic particles in the inorganic reflective layer is large, the adhesion between the wiring and the inorganic reflective layer is poor.
In Comparative Example 2, the inorganic reflective layer is not post-treated, the OH group surface structure absorption coefficient is low, the adhesion between the substrate and the inorganic reflective layer is poor, and the adhesion between the wiring and the inorganic reflective layer is also poor. .
In Comparative Examples 3 and 4, since the firing temperature of the inorganic reflective layer is high, the OH group surface structure absorption coefficient is low, the inorganic reflective layer cannot follow the thermal expansion of the aluminum substrate, cracks occur, and the withstand voltage decreases. The adhesion between the substrate and the inorganic reflective layer is poor.
In Comparative Examples 5 and 6, since the resin binder is used to bind the alumina particles, the heat resistance is inferior, the light resistance is also inferior, and the aging is deteriorated. Moreover, it is inferior to the adhesiveness of wiring and a reflection layer.
Comparative Example 7 has only an anodized film layer on the valve metal and no inorganic reflection layer, but is heated with steam, has a high OH-based surface structure absorption coefficient, has a high withstand voltage, and good thermal conductivity, but has a reflectivity. Inferior to

DESCRIPTION OF

SYMBOLS

1, 11 Valve metal base material 2 Anodized film layer 3 Inorganic reflecting layer 4 Inorganic particle 5 Inorganic binder 6 Micro gap 10 Light emitting element (LED)
13 Indentation 18 Heat sink 19 Wire bonding 20 Metal wiring layer 30 Reflective substrate for light emitting element (reflective substrate)
DESCRIPTION OF SYMBOLS 100 White light emitting diode apparatus 110 Light emitting element 150 Phosphor 160 Resin material

Claims

Comprising an inorganic reflective layer on at least a part of the valve metal substrate, wherein the inorganic reflective layer, Vickers hardness (Hv) 1 GPa or more, the difference in absorbance at wavenumber 3000 cm -1 and a wavenumber 1900 cm -1 as measured by infrared spectroscopy A reflection substrate for a light-emitting element, wherein the OH surface structure absorption coefficient represented by the formula is 0.40 or more.
The reflective substrate for a light-emitting element according to claim 1, further comprising an anodized film layer of the valve metal base material between the valve metal base material and the inorganic reflective layer.
The inorganic reflective layer has at least one inorganic binder selected from the group consisting of aluminum phosphate, aluminum chloride and sodium silicate, a refractive index of 1.5 or more and 1.8 or less, and an average particle size of 0.1 μm or more. The reflective board | substrate for light emitting elements of Claim 1 or 2 containing the inorganic particle of 5 micrometers or less.
The light emitting element reflective substrate according to any one of claims 1 to 3, wherein the inorganic particles are at least one selected from the group consisting of oxides, hydroxides, and inorganic salts.
The reflective substrate for light emitting element according to any one of claims 4 to 5, wherein the inorganic particles are at least one selected from the group consisting of barium sulfate and aluminum oxide.
6. The valve metal according to claim 1, wherein the valve metal is at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth and antimony. Reflective substrate for light emitting element.
The light emitting element reflective substrate according to any one of claims 1 to 6, wherein a thickness of the valve metal base is 0.1 to 2 mm.
The light-emitting element reflective substrate according to any one of claims 1 to 7, wherein the bulb metal is aluminum.
The light emitting element reflective substrate according to any one of claims 1 to 8, wherein the light emitting element reflective substrate has a tensile strength of 30 MPa to 100 MPa.
The light emitting element reflective substrate according to any one of claims 1 to 9, wherein the inorganic particles include two or more kinds.
An inorganic reflective layer having a Vickers hardness (Hv) of 1 GPa or more provided on at least a part of the surface of the valve metal substrate is subjected to a steam treatment or a hydrophilization treatment, and a wave number of 3000 cm −1 and a wave number of 1900 cm measured by infrared spectroscopy. A method for producing a reflective substrate for a light-emitting element, comprising forming an inorganic reflective layer having an OH surface structure absorption coefficient of 0.40 or more, which is indicated by a difference in absorbance of -1 .
The light-emitting element reflection according to claim 11, wherein the inorganic reflective layer is a mixture of an inorganic binder and inorganic particles, applied to the surface of the bubble metal substrate, and fired at a low temperature of 100 ° C to 300 ° C. A method for manufacturing a substrate.
The method for producing a reflective substrate for a light-emitting element according to claim 11 or 12, wherein an inorganic reflective layer is formed on the anodized layer after anodizing the surface of the valve metal substrate.
The light-emitting device according to any one of claims 11 to 13, wherein the following steps (c) and (d) are performed in an arbitrary order after the steps according to any one of claims 11 to 13. Method for manufacturing a reflective substrate:
(C) forming a metal wiring layer for electric signal transmission to the light emitting element and patterning the metal wiring layer;
(D) The process of providing a metal layer in the electrode part corresponded to the part which mounts a light emitting element.
A white light-emitting diode device having a blue light-emitting element on the light-emitting element reflective substrate according to any one of claims 1 to 10, and a fluorescent light-emitting body around and / or above the blue light-emitting element.