HK1170849B - White color reflecting material and process for production thereof - Google Patents

Description

White reflective material and method for producing same

Technical Field

The present invention relates to a white reflective material which is used as a member for packaging a semiconductor optical element, such as a substrate on which a semiconductor optical element such as a semiconductor light emitting element and a solar cell element is mounted, or a reflective plate which houses the optical element and constitutes the periphery of the optical element, and which is stable against light and heat rays, has high reflection efficiency without light leakage, and can stably maintain and reflect the effects for a long period of time, and a method for producing the same.

Background

Light Emitting Diodes (LEDs) are used as light sources for various light emitting devices such as lighting fixtures, traffic lights, and backlights of liquid crystal displays. Such a light emitting diode, particularly a high-luminance light emitting diode, is widely used because it consumes less power and has a long service life than a white lighting device such as an incandescent bulb, a halogen lamp, a mercury lamp, or a fluorescent lamp.

As shown in fig. 12, in an LED used as a light source in a conventional light emitting device, a light emitting element 33 is provided on a base material 40 made of alumina ceramics, glass fiber-containing epoxy resin, or bismaleimide-triazine resin, and lead wires 34a and 34b extending from the light emitting element 33 are connected to wirings 35a and 35b on the base material 40, respectively. The light emitting element 33 on the substrate 40 is surrounded by and integrated with a small white molded package member (reflector plate) 30 of several millimeters (mm) to several centimeters (cm) or so, and the small white molded package member (reflector plate) 30 is made of a resin such as polyether, polyphthalamide, or polyether ether ketone, or an expensive ceramic such as alumina, and is opened in the light emission direction.

When the base material 40 or the package molding member (reflection plate) 30 is made of such a resin, temperature deterioration is caused by lead-free reflow soldering when the semiconductor light emitting device is fixed to a circuit, light deterioration is caused when the wavelength of light is ultraviolet light, and particularly when a high-luminance light emitting diode is used, yellowing or darkening is gradually caused by high-luminance emitted light or high heat generated by the emitted light, deterioration is caused, and the surface thereof becomes dull, resulting in deterioration in reflectance. On the other hand, when the base material 40 or the package molded member (reflection plate) 30 is made of ceramic, there is no deterioration due to ultraviolet rays or deterioration due to heat, but the emitted light leaks out and sufficient illuminance cannot be obtained.

Further, although the surface of the substrate or the package molded member is subjected to plating treatment for reflecting light, there is a problem that the reflectance is lowered due to blackening due to vulcanization although the reflectance is high in the case of silver plating, and the reflectance is lowered due to excellent resistance to vulcanization and oxidation in the case of gold plating, but the reflectance is low, and the substrate or the package molded member is expensive and lacks versatility.

As a reflective material which is less likely to undergo light deterioration without being subjected to plating treatment and has less light leakage, patent document 1 discloses a light reflective material having a weather-resistant layer having ultraviolet absorbing ability on one surface of a light reflective layer composed of a composition containing a white pigment having low decomposition catalytic activity, rutile titanium oxide, and an aromatic polycarbonate resin, and a light shielding layer on the other surface of the light reflective layer.

Light emitting diodes have been manufactured which can emit light in a short wavelength region near the lower limit of the visible region or in an ultraviolet region. The reflection material made of plastic such as polycarbonate resin containing rutile type titanium oxide cannot sufficiently reflect light emitted from such a light emitting diode in a wavelength region of 360nm or more, particularly 380 to 400nm, which is close to the lower limit of the visible region.

Patent document 2 discloses a semiconductor light-emitting device in which a substrate and a light-emitting element are bonded to each other via a resin composition in which anatase-type titanium oxide having a high reflectance in a wide wavelength region is dispersed in an epoxy resin, but the reflectance of the semiconductor light-emitting device changes greatly with time, the epoxy resin gradually deteriorates, and the reflectance decreases with time.

Further, as the light emitting wavelength is shortened and the output is increased, a silicon-based sealing resin excellent in heat resistance and light resistance is often used as the sealing resin for the light emitting diode, but unlike a sealing member made of a resin such as polyether, polyphthalamide, or polyether ether ketone which has been used in the past, there is a problem that the sealing member has insufficient adhesiveness, and therefore, a new design of a sealing member is required.

Therefore, there is a need for a versatile reflecting material which can effectively reflect heat rays in a wavelength region of 380 to 400nm or a visible light region of the wavelength region or more, which cannot be sufficiently reflected by the conventional plastic reflecting material, and further can effectively reflect heat rays in an infrared region having a longer wavelength, can be used not only for lighting equipment for emitting light but also for solar cell modules for photoelectric conversion of sunlight and the like, has excellent heat resistance and light resistance, does not discolor, and does not cause a decrease in reflectance even after long-term use.

Patent document 1: japanese patent laid-open No. 2006-343445

Patent document 2: japanese patent laid-open No. 2008-143981

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a white reflective material having general versatility, which can sufficiently reflect near ultraviolet light or near infrared light in a wavelength range of 380nm or more without light leakage even if complicated surface processing is performed on a reflective layer or the like without plating treatment, is not yellowed or deteriorated even when irradiated with near ultraviolet light, has excellent light resistance, heat resistance and weather resistance, has high mechanical strength and excellent chemical stability, can maintain high whiteness, can be easily molded, and can be manufactured with high productivity at low cost, and to provide a method for manufacturing the white reflective material, and further to provide a white reflective material which can be used as an ink composition for molding a white reflective material into a film shape.

The white reflecting material according to claim 1 of the present invention for achieving the above object is characterized in that a silane coupling agent and Al are dispersed and utilized in a silicone resin or a silicone rubber₂O₃、ZrO₂Or SiO₂And forming and crosslinking a titanium oxide-containing silicone composition by molding anatase-type or rutile-type titanium oxide particles subjected to plating treatment, thereby forming the white reflective material, wherein the silicone resin or the silicone rubber has a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D.

The white reflective material according to claim 2, wherein the titanium oxide particles have an average particle diameter of 0.05 to 50 μm, the white reflective material contains 5 to 400 parts by mass of the titanium oxide particles per 100 parts by mass of the silicone resin or silicone rubber, and the white reflective material has a reflectance of at least 80%.

The white reflective material according to claim 3, wherein the white reflective material is formed into a three-dimensional shape, a film shape, or a plate shape so as to reflect or diffuse in a direction to be focused or diffused.

The white reflective material according to claim 4 is the white reflective material according to claim 3, wherein the white reflective material is in the form of the plate or the mold, and a conductive metal film for connecting to a semiconductor optical element including a light emitting element or a solar cell element is provided on a surface of the white reflective material.

The white reflective material according to claim 5, wherein the film-like base material is provided on the conductive metal film, or the conductive metal film is provided on the film-like base material, as defined in claim 3.

The white reflective material according to claim 6, wherein a support is provided on the film-like base material or the conductive metal film on a side of a surface on which the optical element is not mounted.

The white reflective material according to claim 7, wherein the conductive metal film is provided on the support, and the film-like base material is provided on the conductive wire metal film, as defined in claim 6.

The white reflective material according to claim 8, wherein the thickness of the film is 5 to 2000 μm as defined in claim 3.

The white reflective material according to claim 9 is the white reflective material according to claim 3, wherein the white reflective material is a package molding member that surrounds an optical element including a light emitting element or a solar cell element, and that contains the optical element while being opened in an incident/emission direction of the optical element and gradually expanded into the three-dimensional shape.

A white reflecting material as set forth in claim 10 is the white reflecting material as set forth in claim 9, characterized in that a conductive metal film connected to the light emitting element is provided on a surface thereof, and a base material on which the optical element is mounted and the package molding member are bonded to each other with an adhesive or are bonded to each other by chemical bonding.

The white reflective material according to claim 11, wherein the base material is formed of silicone resin or silicone rubber as defined in claim 10.

The white reflective material according to claim 12, wherein a support is provided on the base material on the side of the surface on which the optical element is not mounted, as defined in claim 10.

The white reflective material according to claim 13 is the white reflective material according to claim 10, wherein the base material contains at least one or more reinforcing materials selected from the group consisting of glass cloth, cellophane, and glass fiber.

The white reflective material according to claim 14 is the white reflective material according to claim 9, wherein a plurality of the molded package members surrounding the optical element are arranged on the base material, and a semiconductor light-emitting device having the optical element or a solar cell having the solar cell element is integrally formed.

The white reflective material according to claim 15, wherein the silicone resin or the silicone rubber has an active silane group selected from the group consisting of a silane group containing a hydrosilyl group, a silane group containing a vinyl group, a silane group containing an alkoxysilyl group, and a silane group containing a hydrolyzable group.

The white reflective material according to claim 16, wherein said white reflective material comprises a silane coupling agent and Al₂O₃、ZrO₂Or SiO₂The plated anatase or rutile titanium oxide and an uncrosslinked silicone resin component or silicone rubber component are used for molding a white reflective material in which anatase or rutile titanium oxide is dispersed in a crosslinked and cured silicone resin or silicone rubber, and are titanium oxide-containing silicone compositions for molding a molded body in which the rubber hardness of the crosslinked and cured silicone resin or silicone rubber in the white reflective material is 30 to 90 Shore A hardness or 5 to 80 Shore D hardness.

The method for producing a white reflective material according to claim 17, wherein the surface of the support made of a non-silicone resin is subjected to a surface activation treatment, and the surface subjected to the surface activation treatment is coated with a silane coupling agent and Al₂O₃、ZrO₂Or SiO₂Liquid state in which anatase or rutile titanium oxide particles subjected to plating treatment are dispersed in uncrosslinked silicone resin or silicone rubberOr a moldable titanium oxide-containing silicone composition, and then cross-linked and cured to form a laminate, wherein the silicone resin or the silicone rubber has a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D.

The method for producing a white reflective material according to claim 18 is the method for producing a white reflective material according to claim 17, wherein a metal conductive layer is further provided on the titanium oxide-containing silicone composition layer which is cured by crosslinking.

A method for producing a white reflective material as claimed in claim 19, wherein a metal conductive layer is provided on a support made of a non-silicone resin, a wiring circuit is formed on the metal conductive layer, a semiconductor light emitting element is connected to the wiring circuit, and a silane coupling agent and Al are provided around the semiconductor light emitting element₂O₃、ZrO₂Or SiO₂A liquid or plastic titanium oxide-containing silicone composition comprising an uncrosslinked silicone resin or silicone rubber having a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D, and a titanium oxide-containing silicone composition having a structure in which surface-treated anatase or rutile titanium oxide particles are dispersed, and then the composition is crosslinked and cured.

In the titanium oxide-containing silicon white reflective material of the present invention, anatase or rutile titanium oxide particles, particularly anatase titanium oxide particles among them, are dispersed in a silicone resin or silicone rubber, so that not only can light in the near ultraviolet wavelength region of 380 to 400nm be reflected with high reflectance and without leakage of light, but also light in the visible region of a wavelength longer than that of the visible region can be reflected with high reflectance and without leakage of light, and further heat rays such as infrared rays of 780nm or more in the long wavelength region of a wavelength longer than that of the visible region can be reflected with high reflectance and without leakage of light.

Further, since the reflecting material is white with good covering properties and is made of a hard silicone resin or a soft silicone rubber which is not easily deteriorated by light, heat or chemical action, it is excellent in light resistance, heat resistance and weather resistance because it is not yellowed, darkened or deteriorated even when exposed to light from a high-brightness light-emitting diode or an ultraviolet light-emitting diode, direct sunlight or high temperature and further contains anatase-type titanium oxide having high photocatalytic activity. In addition, since the resin composition exhibits high mechanical strength, excellent chemical stability, high whiteness maintenance, and excellent durability, it is very excellent as a material for a semiconductor light-emitting device or a solar cell device using a semiconductor optical element.

The reflecting material is free from troublesome surface processing such as plating for reflection, and can be produced in a simple process, in a simple, precise, reliable manner, and in large quantities at low cost, and therefore has high productivity.

The reflective material can be widely used as a reflective material for devices in various fields relating to semiconductor optical elements, such as a substrate or a package molded member used for not only light-emitting elements but also photoelectric conversion elements such as solar cell elements.

The reflective material can be formed into a plate shape, a three-dimensional shape, or a film shape to have a desired shape, and can be used as a white reflective material having improved reflection efficiency. For example, a film is formed on an inexpensive resin member other than silicon, such as an epoxy base material used in the related art, and the resin member is manufactured at low cost with improved productivity, so that thermal deterioration, discoloration, and the like of the base material used in the related art can be eliminated. In this case, a conductive metal film is formed on a white reflective material laminated in a film form on a conventional resin base material by metal foil or metal plating, and then a circuit is formed by etching or the like, whereby the conductive metal film can be used as a circuit board. Further, by providing a semiconductor optical element or a semiconductor optical device on the wiring pattern and connecting the light emitting element and the circuit, the exposed portion of the reflective material becomes a reflective surface having a good efficiency with respect to light emission of the light emitting element.

The reflective material may be formed in a film shape so as to cover the entire surface of the substrate made of a base material such as a conventional epoxy resin or polyimide resin, or the film-shaped portion may be formed as a reflective surface so as to leave a part of the wiring pattern formed on the conventional circuit board and be covered with an ink-like reflective material.

As another embodiment of the reflective material of the present invention, a white reflective film-forming composition containing titanium silicon oxide can be used as an ink, and the type of the support is not limited, and a thin film having excellent smoothness and high reflectance can be formed on the surface of the support by a method such as coating, printing, spraying, or dipping. In the case of a support made of an epoxy resin or bismaleimide-triazine resin, which is yellowed by heat, a film is formed over the entire surface or a portion to be provided with a reflection function by the above-described method, whereby the support is discolored, but since yellowing does not occur on the film surface, a decrease in reflectance due to the yellowing can be prevented. Further, by forming the thin film on a ceramic support or a reflecting plate, the transparency of the ceramic can be covered to prevent leakage of emitted light, and reflected light can be increased.

Drawings

Fig. 1 is a schematic cross-sectional view showing a semiconductor light-emitting device using a white reflective material to which the present invention is applied.

Fig. 2 is a schematic cross-sectional view showing one member (reflection plate) of a package molded body member using a white reflection material to which the present invention is applied.

Fig. 3 is a schematic cross-sectional view showing a manufacturing process of a substrate using a white reflective material to which the present invention is applied.

Fig. 4 is a schematic cross-sectional view showing a solar cell using a white reflective material to which the present invention is applied.

FIG. 5 is a graph showing the correlation between the irradiation wavelength and reflectance of a white reflective material made of silicon containing anatase titanium oxide, a white reflective material made of silicon containing rutile titanium oxide, and a white reflective material containing alumina.

FIG. 6 is a graph showing the correlation between the irradiation wavelength and the reflectance of a white reflective material substrate of the present invention to which the coating system is applied, and a bismaleimide-triazine resin substrate and a glass epoxy resin substrate to which the present invention is not applied.

FIG. 7 is a graph showing the correlation between the irradiation wavelength and the reflectance after heat treatment of a white reflective material substrate of the coating film form to which the present invention is applied, and a bismaleimide-triazine resin substrate and a glass epoxy resin substrate to which the present invention is not applied.

Fig. 8 is a graph showing the correlation between the irradiation wavelength and the reflectance of a substrate on which a white reflective coating film is formed on a bismaleimide-triazine resin substrate to which the present invention is applied.

Fig. 9 is a graph showing the correlation between the irradiation wavelength and the reflectance after the heat treatment of the substrate on which the white reflective coating film is formed on the bismaleimide-triazine resin substrate to which the present invention is applied.

Fig. 10 is a graph showing a correlation between the irradiation wavelength and the reflectance of a substrate on which a white reflective coating film is formed on a glass epoxy resin substrate to which the present invention is applied.

Fig. 11 is a graph showing the correlation between the irradiation wavelength and the reflectance after the heat treatment of the substrate on which the white reflective coating film is formed on the glass epoxy resin substrate to which the present invention is applied.

FIG. 12 is a schematic cross-sectional view showing a conventional semiconductor light-emitting device using a reflective material to which the present invention is not applied.

Detailed Description

The present invention will be described in detail below with reference to embodiments for carrying out the present invention, but the scope of the present invention is not limited to these embodiments.

Referring to fig. 1, a preferred embodiment of the white reflective material made of titanium oxide-containing silicon of the present invention will be described in detail.

As shown in fig. 1, a white reflective material is incorporated in a semiconductor light-emitting device 1, and the white reflective material is used for a base material 16 on which a semiconductor light-emitting element 13 is mounted and a package molding member 10 surrounding the light-emitting element.

The base material 16 is a member constituting a layer on the circuit side of the substrate 20, and is formed of a silicone resin containing the titanium oxide particles 12 b. Copper films 15a and 15b as conductive metal films are provided on the surface of the substrate 16 on the mounting surface side of the semiconductor light-emitting element 13, and a wiring pattern connected to a power supply (not shown) is formed. Two lead wires 14a, 14b extending from the light emitting diode 13 are connected to the copper film 15a and the copper film 15b, respectively. The base material 16 is exposed to the surface of the base material 16 except for the wiring pattern portion, and the titanium oxide particles 12b contained in the portion except for the wiring pattern portion appear white, and have good covering properties as a white reflective material, so that light does not leak.

An insulating support 17 is provided on the surface of the plate-like base 16 on the side of the semiconductor light-emitting element 13 other than the mounting surface, thereby forming a substrate 20. The opening on the injection direction side of the molded body member 10 may be sealed with a light-transmitting material, or the opening may be covered with a transparent plate or a transparent film made of glass or resin instead of sealing the opening, or the opening may be covered with a transparent plate or a transparent film made of glass or resin at the same time as sealing the opening. The encapsulant or transparent sheet or film may also contain pigments, fluorescent agents, phosphorescent agents capable of converting the wavelengths of light transmitted therethrough to desired wavelengths. Further, the opening portion (not shown) on the light exit direction side of the package molded member 10 may be covered with a lens such as a convex lens, a concave lens, or a fresnel lens.

The molded package member 10 is molded from a silicone resin containing the same titanium oxide particles 12a as those used for the base material 16. The molded package member 10 surrounds the semiconductor light-emitting element 13, gradually expands along the inclined inner wall 11 in the light emission direction, and is integrally bonded to the surface of the base material 16 on the mounting surface side of the semiconductor light-emitting element 13 via an adhesive layer (not shown).

As shown in fig. 2, the coating film 18 is formed by coating the anatase-type or rutile-type titanium oxide powder and, if necessary, a silicon composition containing a silane coupling agent in a film form on the inner wall of the ceramic molded package member 10a having an opening gradually enlarged in the injection direction and curing the coating film, and the other type of molded package member may be the molded package member 10a having the coating film 18 formed thereon as described above. This structure has heat resistance and dimensional stability which are advantages of ceramic materials, and prevents light which is a disadvantage thereof from leaking.

Since the molded package members 10 and 10a are filled with the titanium oxide particles 12a, they are white, and since they have good covering properties, they do not leak light, and particularly have extremely high reflectance against light having a wavelength of 380nm or more, particularly 400nm or more. Further, since the molded package members 10 and 10a are made of a silicone resin which is chemically stable and hardly discolored, they do not yellow and can maintain white color even when exposed to near ultraviolet light or high-luminance light for a long time, and are hard and have high mechanical strength, and exhibit excellent light resistance, heat resistance, and weather resistance, and thus are excellent in durability.

The surface of the inner wall 11 of the package molded body member 10 or 10a or the surface of the base material 16 using these white reflective materials may be subjected to surface treatment by polishing or chemical etching, thereby further improving the reflectance.

The semiconductor light emitting device 1 thus formed may be a lighting fixture in which a plurality of groups of substrates 20 on which semiconductor light emitting elements 13 are mounted and package molded members 10 are arranged in order on the periphery. The semiconductor light emitting device 1 using the white reflective material of the present invention has an extremely high reflectance not only in a wavelength region of a near ultraviolet region of 380 to 400nm, but also in a visible light region having a longer wavelength, and further has an extremely high reflectance of heat rays such as infrared rays having a longer wavelength than the above wavelength.

The semiconductor light-emitting device 1 using the white reflective material of the present invention is manufactured through the respective manufacturing steps as described below.

(1) Production of a white reflective substrate 16 on which a copper foil is laminated:

preparation of copper foil:

degreasing the surface of a copper foil having a thickness of 12 to 18 μm, and then performing surface treatment by corona discharge treatment, atmospheric pressure plasma treatment, or ultraviolet treatment to generate hydroxyl groups exposed on the surface of the copper foil. The surface of the copper foil is immersed in a vinylmethoxysiloxane homopolymer, for example

CH₂＝CH－Si(OCH₃)₂－O－[(CH₂＝CH－)Si(－OCH₃)－O－]_j－Si(OCH₃)₂－CH＝CH₂(j is 3 to 4) and then heat-treating the solution to react the hydroxyl groups exposed on the surface of the copper foil with the vinylmethoxysiloxane homopolymer to form silyl ether, thereby forming a reactive silyl group, i.e., a vinylsilyl-containing silyl group. In order to improve the reactivity, a copper foil to be laminated was prepared by immersing the platinum catalyst in a platinum catalyst suspension so that the vinyl group in the active silane group holds the platinum catalyst.

Preparation of silicon composition:

next, a silicon composition including an uncrosslinked silicone resin component or silicone rubber component having silane groups containing hydrogenated silane groups, and anatase-type or rutile-type titanium oxide powder was prepared. The details will be described later.

When the surface-treated copper foil is subjected to flow coating (flow coating) of the silicon composition and crosslinked while being heated and molded, the vinyl group of the silyl group containing the vinylsilyl group and the hydrosilyl group of the silyl group containing the hydrosilyl group undergo an addition reaction, and a titanium oxide-containing silicon white reflective material (substrate 16) in which a copper foil is laminated can be produced.

(2) Circuit formation connection to semiconductor light emitting element:

the wiring 15a and 15b having a desired wiring pattern are formed on the copper thin film 15 laminated on the base 16 by etching using a resist to form a desired circuit. The semiconductor light emitting element 13 is disposed at a position determined by the wiring pattern, and the wires 14a and 14b are ultrasonically welded to connect the semiconductor light emitting element 13 and the wires 15a and 15 b.

(3) Preparation of the package molding member:

on the other hand, a silicon composition containing the same uncrosslinked silicone resin component, anatase or rutile titanium oxide powder, and optionally a silane coupling agent is poured into a lower mold, and the upper mold is closed and heated to crosslink the composition, thereby forming a sealing molded member 10 containing a white reflective material made of titanium oxide silicon.

Further, when the substrate 20 or the molded package member 10 having a higher strength is obtained by applying a silane coupling agent to titanium oxide, adding a siloxane compound, crosslinking the silane coupling agent and the siloxane compound by heating or light irradiation, and molding a silicone resin containing a filler in the intermolecular of a binder in a mold.

(4) Integration of the encapsulating molding member with the base material:

the package molded body member 10 is integrally bonded to a base material 16 including a part of the copper foil circuit with an adhesive while the package molded body member 10 is set with its wide opening portion facing upward so as not to contact the semiconductor light emitting element 13 and the leads 14a and 14b and so as to surround the semiconductor light emitting element 13. Next, the opening of the molded member 10 is sealed with a silicone transparent resin, and the semiconductor light-emitting device 1 is obtained.

The semiconductor light emitting device 1 thus manufactured can be used as follows.

When a current is applied to the semiconductor light-emitting element 13 by the cathode-side copper foil circuit (copper film) 15a and the lead wire 14a, and the anode-side copper foil circuit (copper film) 15b and the lead wire 14b, the semiconductor light-emitting element 13 emits light. A part of the emitted light is directly radiated to the outside from the opening on the side of the emission direction of the package molded body member 10. Another part of the emitted light is reflected by the inner wall 11 of the package molded member 10 or the exposed portion of the white reflective material on the surface of the base material 16 except for the wiring pattern, and is emitted to the outside from the opening on the emission direction side.

The white reflective material made of titanium silicon oxide of the present invention also includes a material for forming a molded white reflective material, and in this case, the white reflective material may be a liquid, plastomer or semisolid, and may be an uncrosslinked silicone resin component or a silicone rubber component, anatase type, rutile type or both titanium oxide powders, and optionally a silicon composition containing a silane coupling agent (the same as the composition for forming a white reflective material, hereinafter, may be simply referred to as "silicon composition"). The silicon composition is coated in a film form and crosslinked, so that the surface of the substrate colored by thermal deterioration can maintain a high reflectance and white color, and for example, as shown in fig. 2, the reflection surface of a ceramic reflection plate having light transmittance is coated in a film form, so that light leakage can be prevented.

The white reflecting material of the present invention may be a film-like substrate 16 formed by coating a silicon composition on a support 17 made of a different material such as an aluminum plate. Alternatively, the film-shaped substrate 16 may be formed into a film shape, or the film-shaped substrate 16 may be bonded to the support 17 via an adhesive layer. The substrate 20 having a three-layer laminated structure may be formed by forming the support 17 and the base 16 into a laminated structure, and providing a conductive metal film (copper thin film) 15 for forming a wiring pattern on the surface of the laminated base 16. Alternatively, the substrate 20 having the base 16 formed thereon may be formed by providing the conductive metal film (copper thin film) 15 having a wiring pattern on the surface of the support 17, forming a printed circuit, and then applying the silicon composition only to the portion requiring the reflection function. As described above, compared with the substrate 20 formed by providing a copper foil on a substrate made of only a white reflective material made of titanium silicon oxide, the substrate 20 formed as a laminate by providing a conductive metal film (copper thin film) such as a copper foil on either one of the base 16 and the support 17 can compensate for the weakness of the physical properties of the silicone resin, and can significantly improve the physical properties of the substrate even if the substrate has the same thickness. In particular, since the white reflective material has a reflective property, the support can compensate for the easy bending of the silicone resin due to its rigidity, and the smooth surface of the support can be reproduced on the surface of the thin white reflective material, it is preferable to use the white reflective material as an electronic circuit board.

In these laminated structures, since the adhesive interface between the base 16, which is a white reflective material, and the support 17 or the conductive metal film (copper thin film) 15 is strongly adhered, distortion or peeling does not occur.

The thickness of these substrates 16 can be adjusted as appropriate depending on the application. The thickness is usually adjusted within a range of 2 μm to 5mm, preferably 5 μm to 2000 μm, and more preferably 10 μm to 100 μm. If the thickness is too thin, the hiding property is lowered, and an appropriate reflectance cannot be obtained. Further, if the thickness is too thick, the surface properties of the reflective material are not further improved, and therefore, it is not necessary to be so thick unless it is desired to improve the mechanical properties.

The method for producing the substrate 20 having the film-like base material 16 will be described in detail with reference to fig. 3(a) and (B) as an example.

First, as shown in fig. 3 a, a white reflective film-forming composition containing titanium oxide silicon, which contains an uncrosslinked silicone resin component, a silicone rubber component, or anatase-type or rutile-type titanium oxide, is applied to the surface of the support 17 by a screen printing method, and crosslinked and cured to form the substrate 16 (the same as in step (a) in fig. a). The surface of the base material 16 is subjected to a surface treatment such as corona discharge treatment, atmospheric pressure plasma treatment, or ultraviolet treatment to generate hydroxyl groups, and then subjected to metal vapor deposition treatment or plating treatment to form a copper thin film 15 as a conductive metal film (the same as the step (b) in fig. a). The copper thin film 15 is masked to form masking layers 21a and 21b (the same as in step (c) in fig. a), and then, acid treatment is performed to etch the masking layers, thereby forming wirings 15a and 15b having a desired wiring pattern (the same as in step (d) in fig. a). The shielding layers 21a and 21b are removed by elution (same as the step (e) in fig. a), and the wires 14a and 14b extending from the semiconductor light emitting element 13 are connected to the wirings 15a and 15b by ultrasonic welding (same as the step (f) in fig. a). The substrate 16 exhibiting high reflectance is exposed at a portion other than the wiring pattern portion.

As shown in fig. 3B, the surface of the support 17 is subjected to a treatment of bonding a conductive metal film (copper foil) to the surface of the support, or a plating treatment to form a copper thin film 15 as a conductive metal film (the same as the step (a) in fig. B), wherein the conductive metal film (copper foil) is degreased and then subjected to a surface treatment such as a corona discharge treatment, an atmospheric pressure plasma treatment, or an ultraviolet treatment. The conductive metal film 15 is masked to form masking layers 21a and 21B (the same as the step (B) in fig. B), and then acid treatment and etching are performed to form wirings 15a and 15B having a desired wiring pattern (the same as the step (c) in fig. B). The masking layers 21a and 21B are then removed by elution (the same as in step (d) in fig. B), and the base materials (coating films) 16a, 16B, and 16c are formed by applying a composition for forming a white reflective film made of titanium oxide-containing silicon oxide containing an uncrosslinked silicon resin component or silicon rubber component and anatase-type or rutile-type titanium oxide to the portions other than the portions of the wiring pattern connected to the leads 14a and 14B extending from the semiconductor light-emitting element 13 by screen printing (the same as in step (e) in fig. B). The semiconductor light emitting element 13 is placed on a desired base material (coating film) 16B, and the semiconductor light emitting element 13 and the wirings 15a and 15B are connected by ultrasonic bonding using the lead wires 14a and 14B (the same as the step (f) in fig. B). Thus, light emitted from the semiconductor light-emitting element is reflected by the base material (coating film).

As shown in fig. 4, another embodiment of the white reflective material is used for the package molded member 10 to which the photoelectric conversion element as the solar cell element 24 is mounted, which is assembled as a module of the solar cell 2.

The molded package member 10 is made of a silicone resin containing titanium oxide particles 12a, and is formed into a plurality of rows each recessed in a bowl shape by being rearranged. The solar cell element 24 is composed of a p-type silicon semiconductor 24a having a substantially spherical shape inside and an n-type silicon semiconductor 24b covering the periphery thereof and PN-bonded thereto. The lower end of the n-type silicon semiconductor 24b is polished to form a notch, and the p-type silicon semiconductor 24a is exposed from the notch. The n-type silicon semiconductor 24b is connected only to the copper film 22b as an electrode structure layer of the negative electrode, while the p-type silicon semiconductor 24a is connected only to the copper film 22a as an electrode structure layer of the positive electrode. The copper films 22a and 22b as both electrodes are isolated and insulated by an insulator layer 23 laminated therebetween. The encapsulating molded body member 10 surrounds the solar cell element 24, gradually expands along the bowl-shaped inner wall 11 in the injection direction, and is integrally bonded to the copper film 22b via an adhesive layer (not shown).

In order to improve the adhesion between the surface of the inner wall 11 of the package molded member 10 and the silicone sealing resin, surface treatment may be performed. Specifically, the bonding method described in the above item "(1) production of a white reflective base material 16 in which copper foil is laminated" can be used.

The package molded body member 10 of the present invention and the method for manufacturing the solar cell module 2 using the same are as follows. The encapsulating molded member 10 is prepared in a bowl shape by curing a silicone resin component, anatase or rutile titanium oxide powder, and optionally a silicon-forming composition containing a silane coupling agent in a mold, and recessing the surrounding portions at equal intervals. A hole is dug in advance on the bowl-shaped concave bottom. A hole is bored in the insulator 23 at a position corresponding to the hole of the bowl-shaped concave bottom of the package molded member 10, and the copper film 22a is bonded to the back surface side of the insulator 23 with an adhesive, and the copper film 22a is exposed through the conductive material filled in the hole of the insulator 23. The copper film 22b is bonded to the surface side of the insulator with an adhesive, and is etched to form a wiring pattern. The hole of the bowl-shaped concave bottom of the package molded body member 10 is made to coincide with the copper film 22a exposed from the hole of the insulator 23, and the package molded body member 10 is bonded to the copper film 22b with an adhesive so as to cover the copper film 22 b. On the other hand, silicon spheres are produced in which a thin film is formed around spherical p-type silicon crystals using n-type silicon crystals. A part of the silicon ball is ground flat, and the n-type silicon semiconductor 24b on the outer periphery is cut out, and the p-type silicon semiconductor 24a inside is exposed from the cut out. The copper film 22a exposed from the hole of the insulator 23 is brought into contact with the exposed portion of the p-type silicon semiconductor 24 a. The solar cell module 2 can be obtained by bringing the n-type silicon semiconductor 24b into contact with only the copper film 22b serving as a negative electrode and bonding and fixing the same.

The solar cell module 2 using the white reflective material of the present invention can be used as follows. As shown in fig. 4, light, for example, sunlight, is incident on the solar cell element 24 of the solar cell module 2. For example, incident sunlight from directly above is incident straight normal to the top of the solar cell elements 24. Incident sunlight slightly off-top is reflected by the inner wall 11 of the package molding member 10 and is incident substantially perpendicularly to the side surface of the solar cell element 24. As described above, when light incident on the solar cell module 2 efficiently reaches the PN junction interface between the n-type silicon semiconductor 24b and the p-type silicon semiconductor 24a to generate photovoltaic power, and the photovoltaic power is integrated into a circuit, photocurrent can flow.

When the package molded member 10 used in the solar cell module 2 is a package molded member 10 made of a material other than a white reflective material made of titanium oxide silicon such as ceramic, the surface of the package molded member 10 is covered with the white reflective material of the present invention in a film form, and light is reflected in a direction to be focused.

The following description will be made of various materials used for the white reflective material of the present invention. The silicon composition has thermosetting properties and exhibits excellent heat resistance, durability, and light resistance, and contains titanium oxide of anatase type or rutile type dispersed in an uncrosslinked silicone resin component or silicone rubber component for forming the white reflective film or a white reflective material of a desired shape. In addition, a solvent or an additive may be appropriately added to the silicon composition to adjust the viscosity thereof, so that a coating film having a desired thickness or a formed article having a desired shape can be formed without generating droplets. Since this titanium oxide-containing silicone composition uses an uncrosslinked silicone resin component or silicone rubber component, it can be used without any solvent such as a diluent and can be used as it is, as compared with a conventional resist which needs to be used up because of photocurability, and thus has good storage stability. Examples of diluents include: trade name: ZEORORA (fluorine-based solvent manufactured by Asahi glass Co., Ltd., Japan), xylene, toluene, ether, diluent, 1-bromopropane, etc. In addition, a low viscosity silicone diluent that reacts to form a cured silicone product may also be used. Among them, the diluent is preferable because it is easily available and does not increase the viscosity, and thus has good processability.

The silicon composition of the present invention preferably contains 5 to 400 parts by mass of anatase-type or rutile-type titanium oxide per 100 parts by mass of the uncrosslinked silicone resin component or silicone rubber component. When the amount of the white reflective material of the present invention formed using the silicon composition is less than 5 parts by mass, sufficient reflection cannot be obtained, and particularly, the reflectance is lowered in a long wavelength region, while when it exceeds 400 parts by mass, it is difficult to disperse titanium oxide.

In the anatase-type or rutile-type titanium oxide of the present invention, the small particle size and the large particle size are combined, so that the blending fraction can be increased to achieve the densest filling, and the large particle size titanium oxide is used, so that the covering power can be improved. The average particle size is preferably 0.05 to 50 μm. If the average particle diameter is less than 0.05. mu.m, the hiding power tends to be lowered. When the average particle size is larger than 50 μm, the coating conditions of the composition become unstable, and the surface quality after coating is also unstable. The shape of the titanium oxide is not particularly limited, and it may be in any particle form, and for example, a flake form, an amorphous form, or a spherical form of particles may be used, but the particle diameter is preferably 0.1 to 10 μm, and Al may be used₂O₃、ZrO₂、SiO₂And the like. The surface treatment is preferably performed because anatase-type titanium oxide has a strong photocatalytic effect.

Further, rutile type titanium oxide is preferable for reflecting light in the visible region, and anatase type titanium oxide is preferable for reflecting light in the wavelength region of 380 to 400 nm. In particular, anatase titanium oxide is preferable because it can sufficiently reflect not only light in a wavelength region of 380 to 400nm but also light in a visible light region larger than the wavelength region and heat rays of 780nm or more such as infrared rays having a longer wavelength than the visible light region.

The silicone resin preferably contains 5 to 400 parts by mass of anatase type titanium oxide or rutile type titanium oxide, and more preferably 10 to 200 parts by mass, per 100 parts by mass of the silicone resin. If the content is less than 5 parts by mass, the hiding power is small, and the reflectance cannot be secured. When the content exceeds 400 parts by mass, coating tends to be difficult.

Since anatase-type titanium oxide powder functions as a strong photodecomposition catalyst to the extent of decomposing foreign matters such as dust, when added to a polymer compound such as a thermoplastic resin such as polycarbonate, polyphthalamide, or polyether ether ketone, the polymer compound is generally decomposed to cause yellowing, or deterioration and cracking. However, since silicon is also chemically stable to anatase titanium oxide, the white reflective material can be maintained for a long period of time without deterioration or deformation.

The white reflective film contains 10 mass% of each powder of anatase type titanium oxide, rutile type titanium oxide, and aluminum oxide in silicon, and fig. 5 shows a correlation between an irradiation wavelength and a reflectance in the case where the white reflective film of 30 μm is formed. FIG. 5 clearly shows that at a wavelength of 400nm, the reflectance of rutile titanium oxide is only 30%, whereas that of anatase titanium oxide exceeds 80%. Particularly, under the wavelength of 380-400 nm, the reflectance of anatase type titanium oxide is higher than that of rutile type titanium oxide. On the other hand, although the reflectance of the aluminum oxide reflective film is improved from the vicinity of the wavelength of 300nm, the reflectance in the long wavelength region is only about 80% at the highest as compared with 380nm, and is far inferior to anatase-type titanium oxide and rutile-type titanium oxide.

The refractive index of anatase type titanium oxide is 2.45 to 2.55, the refractive index of rutile type titanium oxide is 2.61 to 2.90, and the refractive index of alumina is about 1.76. Since anatase type titanium oxide has a refractive index equal to that of rutile type titanium oxide and higher than that of alumina, the reflectance is high.

Inorganic white pigments such as alumina, barium sulfate, magnesium oxide, aluminum nitride, boron nitride (hexagonal, cubic), silica (crystalline silica, fused silica), barium titanate, kaolin, talc, and aluminum powder may be added to the white reflective material of the present invention as appropriate, together with titanium oxide, depending on the use for heat dissipation, the use for reflection of ultraviolet rays, and the like. Although light leakage occurs even when only the inorganic white pigment such as alumina or barium sulfate, which is the most dispersible in silicon, is contained, it is preferable that these inorganic white pigments are present together with titanium oxide because the functions such as heat dissipation and reflection of ultraviolet rays are added in addition to the improvement of reflectance without light leakage.

The silicone resin or silicone rubber used for the white reflective material of the present invention is not particularly limited, and a hard silicone resin, a soft silicone resin, a hard silicone rubber, and a soft silicone rubber can be used. Examples thereof include silane compounds exemplified by poly (dialkylsiloxane) such as poly (dimethylsiloxane) and poly (diarylsiloxane) such as poly (diphenylsiloxane).

Of these, polydimethylsiloxane having a low refractive index is preferable, and the reflectance can be improved. Since the polydimethylsiloxane does not contain a phenyl group which causes yellowing or contains a very small amount of phenyl groups, heat resistance and ultraviolet resistance can be improved.

Phenyl-containing phenylsilicon, on the other hand, is suitable for use in the manufacture of hard white reflective materials because it increases the hardness of the material.

Such silicon is a three-dimensionally crosslinked silicon, and since the Si group in the middle of the three-dimensionally crosslinked silane compound is an alkylsilyl group, a dialkylsilyl group, a vinylsilyl group, a divinylsilyl group, a hydrosilyl group, or a dihydrosilyl group, or a plurality of these groups are present, the three-dimensionally crosslinked silane compound is a so-called network three-dimensionally crosslinked. The silicone compounds are condensed and crosslinked by dealcoholization of the respective alkylsilyl groups or dialkylsilyl groups, or the addition and crosslinking of the vinylsilyl groups or divinylsilyl groups and hydrosilyl groups or dihydrosilyl groups are carried out by heating or light irradiation in a solvent-free atmosphere in the presence of a platinum catalyst such as a platinum complex, between the silicone compounds and optionally added silane coupling agents. Among the siloxane compounds, it is preferable to use an addition-crosslinkable silane compound. May also have, for example, diphenylsilanyloxy (-Si (C)₆H₅)₂-O-) or dimethylsiloxy (-Si (O) (Si)CH₃)₂-O-) and the like. The siloxane compound is preferably a silane compound containing repeating units of dimethylsilyloxy groups, such as alkylsilyl, dialkylsilyl, vinylsilyl, divinylsilyl, hydrosilyl and dihydrosilyl, because discoloration thereof is less likely to occur.

Since these silicon can have rubber elasticity in a wide temperature range of-40 ℃ to +200 ℃, when laminated on the support, the silicon changes in accordance with dimensional changes due to thermal expansion and thermal contraction caused by the temperature of the support, and therefore, cracks are not generated. As a result, one factor causing the decrease in reflectance can be excluded.

Although the ceramic coating layer and the like have excellent heat resistance, they do not change with thermal expansion and thermal contraction of the support, and therefore cracks are generated, resulting in a decrease in reflectance.

The silicone rubber can maintain a high reflectance for a long period of time because of its rubber elasticity and heat resistance. Further, even if the silicone resin is hard, the phenyl silicone resin has a characteristic that the hardness is lowered at a high temperature, and therefore, the linear expansion of the support can be sufficiently coped with.

The hardness of the rubber is preferably 30 to 90 Shore A hardness and 5 to 80 Shore D hardness.

Examples of a method for printing a titanium oxide-containing silicone composition for forming a film-like white reflective material include: screen printing, transfer printing, offset printing, gravure printing, and relief printing. Examples of the coating method include: ink-jet method, spray method, roll method, knife coating, air nozzle coating, dip coating, and bar coating, etc. A screen printing method capable of forming a white reflective film according to a desired wiring pattern of a circuit board is preferable because a screen or a metal mask can be used.

In the present invention, examples of the silane coupling agent to be used as needed include silane coupling agents having an alkyl group, a vinyl group, an amine group, or an epoxy group as a reactive functional group. As the coupling agent, in addition to a silane coupling agent, a coupling agent of titanate or aluminate may be used.

When the silane coupling agent is contained in the siloxane compound, the titanium oxide can be more firmly taken into the network structure than in the case where the silane coupling agent is not contained, and therefore the strength of the silicone resin can be significantly enhanced.

In particular, in the white reflective material made of silicon containing titanium oxide treated with a silane coupling agent, since titanium oxide is crosslinked with silicon via the silane coupling agent, the flexural strength, wettability and dispersibility thereof can be improved, and the quality thereof can be improved. In the silane coupling agent treatment, for example, 1 mass% of a silane coupling agent is added to titanium oxide, and the mixture is stirred with a Henschel Mixer (Henschel Mixer) to perform surface treatment, and dried at 100 to 130 ℃ for 30 to 90 minutes.

The molding method other than the coating method of the white reflective material of the present invention is performed by a method such as compression molding, injection molding, transfer molding, liquid silicone rubber injection molding (LIMS), extrusion molding, and extrusion molding using a die.

In the present invention, examples of the adhesive used for bonding the package formed member 10 to the base material 16 or bonding the package formed member 10 to the conductive metal film such as the copper films 15a, 15b, 22a, and 22b include: SE9185 (trade name; manufactured by Dow Corning Toray Co., Ltd., Japan) or SE9186 (trade name; manufactured by Dow Corning Toray Co., Ltd., Japan).

In the lamination of the combination of the conductive metal film such as copper foil, the package molded member, the white reflective substrate in a film or plate shape, and the support of the present invention, the lamination can be performed by using the above adhesive in addition to the lamination by chemical bonding in which the adhesive surface is activated by surface treatment.

AsThe method of bonding by surface treatment, more specifically, degreasing the surface of a metal foil, and then performing surface treatment such as corona discharge treatment, atmospheric pressure plasma treatment, or ultraviolet treatment to generate hydroxyl groups exposed from the surface of the metal foil. The metal foil is surface-impregnated with a vinylmethoxysiloxane homopolymer, such as CH₂＝CH－Si(OCH₃)₂－O－[(CH₂＝CH－)Si(－OCH₃)－O－]_j－Si(OCH₃)₂－CH＝CH₂(j is 3 to 4) and then heat-treating the solution to react the hydroxyl groups formed on the surface of the metal foil with the vinylmethoxysiloxane homopolymer to form silyl ether, thereby forming a reactive silyl group containing a vinylsilyl group. In order to improve the reactivity, it was immersed in a platinum catalyst suspension so that the vinyl group in the active silane group retained the platinum catalyst. Next, when one surface of the surface-treated metal foil is brought into contact with a silicon raw material composition containing a silicon resin component or a silicon rubber component having a silane group containing a silyl hydride group, and anatase-type titanium oxide, and heated and sulfurized, the vinyl group of the silyl group containing a vinylsilyl group and the silyl hydride group of the silyl group containing a hydrosilyl group undergo an addition reaction, and as a result, the metal foil and the white reflective material are strongly bonded through strong chemical bonding.

Here, an example of a silicon composition using a silicone rubber component in which a vinyl methoxysiloxane homopolymer having a vinyl group as a reactive group is used to bond the reactive group to a metal film and a hydrosilyl-containing silyl group as the reactive group is used is shown, but the reactive group may be any of a hydrosilyl-containing silyl group, a vinyl-containing silyl group, an alkoxysilyl-containing silyl group, and a hydrolyzable group-containing silyl group, and the reactive group may be any of a hydrosilyl-containing silyl group, a vinyl silyl-containing silyl group, an alkoxysilyl-containing silyl group, and a hydrolyzable group-containing silyl group in the silicone rubber component or the silicone resin component. Examples of the combination of the active group and the reactive group include: when one of them is a silyl group containing a hydrosilyl group, the other is a silyl group containing a vinylsilyl group, or when one of them is a silyl group containing an alkoxysilyl group, the other is a silyl group containing an alkoxysilyl group or a silyl group containing a hydrolyzable group, or both are silyl groups containing a hydrolyzable group.

These reactive silane groups are formed by reacting hydroxyl groups on the surface of the metal film with alkoxysilyl groups of the functional alkoxysilyl compound.

The example in which the white reflective material is used for a light emitting diode package or a solar cell module is shown, but the white reflective material may be used for a substrate that reflects light or heat ray, such as a semiconductor module substrate, an integrated circuit substrate, a high-frequency circuit substrate, a circuit substrate, and a solar cell substrate. They may also be used as a housing or cover, thus being formed in one piece.

As the plating treatment for forming the conductive metal film of the present invention, the following plating methods can be used: nickel plating, copper plating, silver plating, gold plating, chromium plating, vanadium plating, and the like, and these plating may be combined to form a conductive metal film.

The support 17 is not particularly limited, and examples thereof include supports made of ceramics, bismaleimide-triazine resin, glass, metal aluminum, paper phenol resin, electric wood, epoxy resin containing glass fiber, polytetrafluoroethylene, paper epoxy, polyamide, polyimide, silicone resin, and silicone rubber, and supports containing a reinforcing material selected from glass fiber cloth, glass paper, and glass fiber in these supports.

Examples

An example in which the white reflective material made of titanium oxide-containing silicon of the present invention is prepared in a trial manner and incorporated in a semiconductor light emitting device will be described below.

(example 1)

To 100 parts by mass of a silicone resin (trade name SR-7010; manufactured by Dow Corning Toray, Japan) was added 10 parts by mass of anatase-type titanium oxide (trade name SA-1; manufactured by Sakai Chemical Industry Co., Ltd.) and cured at 170 ℃ for 5 minutes under heat and pressure to prepare a white reflective plate having a length of 70mm, a width of 70mm and a thickness of 1 mm. Thereafter, annealing was performed at 170 ℃ for 90 minutes, thereby preparing an assay sample. The reflectance after 1000 hours at 150 ℃ was measured using a spectrophotometer UV-3150 (manufactured by SHIMADZU Co., Ltd.). Here, reflectance was measured for light of three wavelengths (380nm, 550nm, and 780 nm). The measurement results are shown in table 1 below.

[ Table 1]

TABLE 1

Evaluation of reflectance after lapse of a certain period of time at high temperature

Table 1 shows that the reflective material is excellent in light resistance and heat resistance because no significant decrease in reflectance is observed even after 1000 hours has elapsed and yellowing or deterioration does not occur, and thus it is a useful reflective material.

(example 2 and comparative example 1)

100 parts by mass of a dispersed rutile type titanium oxide (trade name SR-1; made by Sakai Chemical Industry Co., Ltd.) was added to 100 parts by mass of a bismaleimide-triazine resin (BT resin) and a glass epoxy resin (GE resin), respectively, to prepare one substrate having a film thickness of 50 μm each.

On the other hand, a bismaleimide-triazine resin substrate and a glass epoxy resin substrate having a thickness of 25 μm were obtained in the same manner as described above.

A white reflection plate having a thickness of 50 μm was obtained by applying a silicon composition obtained by adding 100 parts by mass of rutile type titanium oxide (trade name SR-1; manufactured by Sakai Chemical Industry co., Ltd.) to the silicon resin used in example 1, on each of substrates (BT resin substrate, GE resin substrate) having a thickness of 25 μm using a bar coater (barcoat) to prepare a laminate having a silicon resin composition coating film having a thickness of 25 μm.

The 4 kinds of white reflection plates were evaluated in the same manner as in example 1. The measurement wavelength is a reflectance measured in the range of 200nm to 1000 nm.

The reflectance results before heating are shown in fig. 6, and the reflectance results after heating are shown in fig. 7.

Comparative evaluation of reflectance of conventional substrate and white reflecting plate of the present invention at high temperature over a period of time

Fig. 6 and 7 show that the reflectance can be improved by applying the composition for forming a white reflective film containing titanium oxide-silicon on the BT resin substrate and the GE resin substrate. Further, even after the heat treatment, the laminated white reflective material coated with the composition for forming a white reflective film made of titanium oxide silicon can maintain a high reflectance.

(example 3)

On a BT resin substrate having a thickness of 25 μm obtained in the same manner as in example 2, titanium oxide-containing silicone compositions having a blending ratio of 10 parts by mass (phr), 25phr, 50phr and 250phr with respect to 100 parts by mass of a silicone resin and rutile titanium oxide were applied as films having a thickness of 25 μm, respectively, to obtain a laminated white reflective material having a thickness of 50 μm. The same reflectance measurement as in example 2 was performed, and the correlation between the irradiation wavelength and the reflectance is shown in fig. 8. Further, the same heat treatment and reflectance measurement as in example 2 were performed, and the correlation between the irradiation wavelength and the reflectance is shown in fig. 9.

Evaluation of reflectance of rutile titanium oxide at each addition portion and comparative evaluation of reflectance after heating in a laminated white reflector having a coating thickness of 25 μm applied to a BT resin substrate

FIG. 8 shows that the reflectance of the laminated white reflective substrate obtained by adding 10phr of the dispersed rutile titanium oxide was 90% or more. FIG. 9 shows that, in consideration of the change over time of heating, 25phr or more of rutile-type titanium oxide must be added to ensure a reflectance of 80%. From this fact, it is found that 10phr or more is preferable, and 25phr or more is more preferable in consideration of the change with time of heating.

(example 4)

On a GE resin substrate having a thickness of 25 μm obtained in the same manner as in example 2, titanium oxide-containing silicone compositions having a blending ratio of 10 parts by mass (phr), 25phr, 50phr and 250phr with respect to 100 parts by mass of a silicone resin and rutile titanium oxide were applied to form films having a thickness of 25 μm, respectively, to obtain a laminated white reflective material having a thickness of 50 μm. The same reflectance measurement as in example 2 was performed, and the correlation between the irradiation wavelength and the reflectance is shown in fig. 10. Further, the same heat treatment and reflectance measurement as in example 2 were performed, and the correlation between the irradiation wavelength and the reflectance is shown in fig. 11.

Fig. 10 shows the correlation between the irradiation wavelength and the reflectance of a substrate having a film thickness of 25 μm, which was coated with each of the titanium oxide-containing white reflective film-forming compositions made of silicon dioxide, wherein the rutile titanium oxide was blended in an amount of 10phr, 25phr, 50phr, and 250phr, respectively. Fig. 11 shows the correlation between the irradiation wavelength and reflectance after heat treatment of a substrate having a film thickness of 25 μm, which was coated with each of the titanium oxide-containing white reflective film-forming compositions made of silicon, in which the rutile titanium oxide was blended in an amount of 10phr, 25phr, 50phr, and 250phr, respectively.

Evaluation of reflectance of rutile titanium oxide at each addition part and comparative evaluation of reflectance after heating in a laminated white reflector having a coating thickness of 25 μm applied to a GE resin substrate

FIG. 10 shows that the reflectance of the laminated white reflective substrate obtained by adding 25phr of the dispersed rutile titanium oxide was 80% or more. FIG. 11 shows that, in order to ensure a reflectance of 80%, 50phr or more of rutile-type titanium oxide must be added in consideration of the change over time of heating. From this result, it is found that the amount of rutile titanium oxide to be added is preferably 25phr or more, and more preferably 50phr or more in consideration of the change with time of heating.

As described above, by applying the titanium oxide-containing silicone composition of the present invention to a conventional substrate, a white reflective material having an improved reflectance can be obtained, and even when the heating time changes, a white reflective substrate having a higher reflectance than that of the conventional one can be obtained by adjusting the content of rutile titanium oxide. This shows that the material is useful as a reflective material for circuit boards and semiconductor light-emitting devices.

Industrial applicability of the invention

The titanium oxide-containing silicon white reflective material of the present invention is useful for an electronic circuit board on which a semiconductor light-emitting device such as a light-emitting diode (LED), an optical semiconductor package, and a semiconductor light-emitting element are mounted, and a lighting fixture and a backlight reflector using the same. The white reflective material is suitable for use in a solar cell as a base material for reflecting incident light and condensing the light on a photoelectric conversion element.

Description of the reference symbols

1: semiconductor light emitting device

2: solar cell module

10: package formed body member

10 a: ceramic package molding member

11: inner wall

12a, 12 b: anatase type titanium oxide particles

13: semiconductor light emitting element

14a, 14 b: conducting wire

15. 15a, 15 b: conductive metal film (copper film)

16. 16a, 16b, 16 c: base material (coating film) of white reflecting material

17: support body

18: coating film of white reflective material

20: substrate

21a, 21 b: shielding layer

22a, 22 b: conductive metal film (copper film)

23: insulator

24: solar cell element

24 a: p-type silicon semiconductor

24 b: n-type silicon semiconductor

30: package formed body member

33: semiconductor light emitting element

34a, 34 b: conducting wire

35a, 35 b: conductive metal film (copper film)

40: base material

Claims (19)

1. A white reflective material, characterized in that,

dispersing silane coupling agent and Al in silicone resin or silicone rubber₂O₃、ZrO₂And/or SiO₂And forming and crosslinking a titanium oxide-containing silicone composition by molding anatase-type or rutile-type titanium oxide particles subjected to plating treatment, thereby forming the white reflective material, wherein the silicone resin or the silicone rubber has a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D.

2. The white reflective material of claim 1,

the titanium oxide particles have an average particle diameter of 0.05 to 50 [ mu ] m, the white reflective material contains 5 to 400 parts by mass of the titanium oxide particles per 100 parts by mass of the silicone resin or silicone rubber, and the reflectance of the white reflective material is 80% or more.

3. The white reflective material of claim 1,

the white reflective material is shaped in a three-dimensional shape, a film shape, or a plate shape so as to be reflected or diffusely reflected toward a direction to be focused or diffused.

4. The white reflective material of claim 3,

the white reflecting material is in the form of the plate or film, and a conductive metal film for connecting to a semiconductor optical element including a light emitting element or a solar cell element is provided on a surface of the white reflecting material.

5. The white reflective material of claim 4,

the conductive metal film may be provided with a substrate in the form of a film, or the conductive metal film may be provided on a film-like substrate.

6. The white reflective material of claim 5,

a support is provided on the substrate or the conductive metal film on the side of the surface on which the optical element is not mounted.

7. The white reflective material of claim 6,

the conductive metal film is provided on the support, and the film-like base material is provided on the conductive metal film.

8. The white reflective material of claim 3,

the thickness of the film is 5 to 2000 μm.

9. The white reflective material of claim 3,

the white reflective material is a package molding member that surrounds an optical element including a light emitting element or a solar cell element, and that accommodates the optical element while opening in the incident/emission direction of the optical element and gradually expanding into the three-dimensional shape.

10. The white reflective material of claim 9,

the conductive metal film connected to the optical element is provided on the surface of the base material, and the base material on which the optical element is mounted and the package molding member are bonded to each other with an adhesive or are bonded to each other by chemical bonding.

11. The white reflective material of claim 10,

the base material is formed of silicone resin or silicone rubber.

12. The white reflective material of claim 10,

a support is provided on the substrate on the side of the surface on which the optical element is not mounted.

13. The white reflective material of claim 10,

the base material contains at least one reinforcing material selected from glass cloth, glass paper and glass fiber.

14. The white reflective material of claim 10,

the substrate is provided with a plurality of the package molded body members arranged so as to surround the optical element, and the semiconductor light-emitting device having the optical element or the solar cell having the solar cell element is integrally formed.

15. The white reflective material of claim 1,

the silicone resin or silicone rubber has an active silane group selected from a silane group containing a hydrosilyl group, a silane group containing a vinyl group, a silane group containing an alkoxysilyl group, and a silane group containing a hydrolyzable group.

16. A white reflective material, characterized in that,

the white reflecting material contains silane coupling agent and Al₂O₃、ZrO₂Or SiO₂The plated anatase or rutile titanium oxide and an uncrosslinked silicone resin component or silicone rubber component are used for molding a white reflective material in which anatase or rutile titanium oxide is dispersed in a crosslinked and cured silicone resin or silicone rubber, and are titanium oxide-containing silicone compositions for molding a molded body in which the rubber hardness of the crosslinked and cured silicone resin or silicone rubber in the white reflective material is 30 to 90 Shore A hardness or 5 to 80 Shore D hardness.

17. A method for producing a white reflective material, characterized in that,

surface activation treatment is performed on the surface of a support body made of non-silicone resin, and the surface subjected to the surface activation treatment is coated with a silane coupling agent and Al₂O₃、ZrO₂Or SiO₂Liquid or plastic titanium oxide-containing silicone composition in which anatase or rutile titanium oxide particles subjected to plating treatment are dispersed in uncrosslinked silicone resin or silicone rubberThe silicone resin or the silicone rubber has a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D, and is cured by crosslinking to form a laminate.

18. The method for producing a white reflective material according to claim 17,

and a metal conductive layer is arranged above the titanium oxide-containing silicone composition layer which is solidified by crosslinking.

19. A method for producing a white reflective material, characterized in that,

a metal conductive layer is provided on a support made of a non-silicone resin, a wiring circuit is formed on the metal conductive layer, a semiconductor light emitting element is connected to the wiring circuit, and a silane coupling agent and Al are provided around the semiconductor light emitting element₂O₃、ZrO₂Or SiO₂A liquid or plastic titanium oxide-containing silicone composition comprising a plating-treated anatase or rutile titanium oxide particles dispersed in an uncrosslinked silicone resin or silicone rubber having a rubber hardness of 30 to 90 Shore A or 5 to 80 Shore D, and then curing the composition by crosslinking.