JP5514702B2 - Cover-lay film, light-emitting element mounting substrate, and light source device - Google Patents

Description

  The present invention relates to a printed circuit board, in particular, a coverlay film for protecting a conductor circuit that protects the surface of a substrate on which a light emitting element such as an LED is mounted, a light emitting element mounting substrate formed by laminating the coverlay film, and a light source device. More specifically, the present invention relates to a cover lay film or the like that has a high reflectivity and suppresses a decrease in reflectivity even under a high-temperature heat load environment or a light resistance test environment.

  Since chip-type LEDs that are mounted directly on the printed circuit board pattern and are resin-sealed are advantageous for miniaturization and thinning, they can be used in electronic devices such as numeric keypad lighting for mobile phones and backlights for small liquid crystal displays. Widely used.

  In recent years, the improvement in the technology for increasing the brightness of LEDs has been remarkably improved, and the LEDs have become more bright, but along with this, the amount of heat generated by the LED elements themselves has increased, and the thermal load on the periphery of the printed circuit board has increased, The LED element ambient temperature is sometimes over 100 ° C. Moreover, in the manufacturing process of the LED mounting substrate, the thermosetting treatment of the sealing resin and the use of lead (Pb) -free solder have progressed, and the reflow process may take a temperature of about 260 to 300 ° C. Exposed to the environment. Under such a heat load environment, a conventional white photo-curing and thermosetting solder resist is coated to form a white printed wiring board made of a thermosetting resin composition. There is a tendency for the whiteness to decrease and the reflection efficiency to be inferior, such as yellowing of the printed wiring board, and there is still room for improvement as a substrate for mounting next-generation high-brightness LEDs. In addition, products equipped with a white printed wiring board that is coated with a white solder resist are expected to have long-term reliability in the future. There was a tendency for the reflectance to be inferior. On the other hand, ceramic substrates are superior in terms of heat resistance, but due to their hard and brittle nature, there is a limit to reducing the area and thickness, making it difficult to handle as a substrate for future general lighting and display applications. Of a heat-resistant coverlay film and a printed wiring board formed by laminating a coverlay film that does not discolor under high-temperature heat load, does not deteriorate reflectance, and can handle a large area Development was required.

  In addition, printed circuit boards are formed with precisely designed conductor circuits, etc., using a printing method, and covered with a coverlay film to protect conductor circuits such as insulation, rust prevention, and scratch protection. Has been. For example, Patent Document 1 includes a resin composition containing 65 to 35% by weight of a polyaryl ketone resin having a crystal melting peak temperature of 260 ° C. or higher and 35 to 65% by weight of an amorphous polyetherimide resin, A coverlay film in which the crystallinity of the composition is appropriately advanced is disclosed.

Japanese Patent No. 3514668

  Since a printed circuit board on which a light emitting element such as one or a plurality of LEDs is mounted has a conductor circuit, the conductor circuit needs to be protected. The above-mentioned Patent Document 1 shows characteristics suitable for adhesion to the surface of a printed wiring board when heated to a low temperature of 260 ° C. or lower by utilizing the crystallinity of the thermoplastic resin composition, and in a relatively short time. A cover lay film that can be bonded and exhibits heat resistance that can withstand 260 ° C. after heat fusion is disclosed. In particular, in order to laminate on a printed wiring board on which an LED is mounted, it is described in Patent Document 1. A coverlay film that does not take into account the reflectance cannot be used as it is.

  Therefore, the problem of the present invention is that the printed wiring board for LED mounting, which has a high reflectance in the visible light region, has high heat resistance, has a small decrease in reflectance under a high-temperature heat load environment, and can cope with a large area. And a light source device mounting substrate and a light source device obtained by laminating the coverlay film.

  As a result of intensive studies to further improve the problem of reflectance, a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler are provided. Cover for protecting a conductive circuit of a printed wiring board having an average reflectance at a wavelength of 400 to 800 nm of 80% or more and a reduction rate of the reflectance at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes being 5% or less The lay film has been found to solve the above problems, and has completed the present invention.

  That is, the first present invention comprises a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler, and has an average reflectance at a wavelength of 400 to 800 nm. It is a coverlay film for protecting a conductor circuit of a printed wiring board, which is 80% or more and has a reflectance reduction rate of 5% or less at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes.

  In the first aspect of the present invention, the thermoplastic resin includes a crystalline thermoplastic resin having a crystal melting peak temperature of 260 or higher, an amorphous thermoplastic resin having a glass transition temperature of 260 ° C. or higher, and a liquid crystal transition temperature of 260 ° C. or higher. Any one or more selected from liquid crystal polymers is preferable.

  In the first aspect of the present invention, the resin layer (B) is preferably cured by radiation.

  In the first aspect of the present invention, the inorganic filler preferably contains at least titanium oxide.

Furthermore, in the first aspect of the present invention, the average value of the linear expansion coefficients of MD and TD of the resin layer (A) containing the thermoplastic resin is preferably 35 × 10 ⁻⁶ / ° C. or less.

  In the first invention, the thickness of the film is preferably 3 to 500 μm.

  In the first aspect of the present invention, the average reflectance at a wavelength of 350 to 400 nm is preferably 40% or more.

  According to a second aspect of the present invention, a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler are provided on a substrate on which at least one light emitting element is mounted. The protective layer has an average reflectance of 80% or more at a wavelength of 400 to 800 nm, and a reduction rate of the reflectance at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes is 5%. The light-emitting element mounting substrate is characterized by the following.

  In the third aspect of the present invention, a conductor circuit is formed on the light emitting element mounting substrate according to the second aspect of the present invention, the substrate and the light emitting element mounted on the substrate are electrically connected, and the light emitting element is sealed with resin. It is the light source device characterized by being formed.

  According to the present invention, the conductor of a printed wiring board has high reflectivity in the visible light region, high heat resistance, excellent dimensional stability, and low decrease in reflectivity under high temperature heat load environment and light resistance test environment. A cover-lay film for circuit protection, a light-emitting element mounting substrate on which a conductor circuit protection layer is formed, and a light source device can be provided. These characteristics are particularly suitable for protecting a conductor circuit of a light-emitting element mounting substrate. It can be used.

FIG. 1 is a diagram illustrating an embodiment of a light emitting element mounting substrate according to the present invention. FIG. 2 is a diagram illustrating an embodiment of a light emitting element mounting substrate according to the present invention.

  Hereinafter, although embodiment of this invention is described, the scope of the present invention is not limited to this embodiment.

<Coverlay film>
The coverlay film according to the first aspect of the present invention includes a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler, and has a wavelength of 400 to 800 nm. As long as the average reflectance at 80 nm is 80% or more and the rate of decrease in reflectance at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes is 5% or less, there is no particular limitation, and thermoplasticity By providing a resin layer (A) containing a resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler, a very high reflection characteristic can be obtained.

As described above, the cover lay film according to the first aspect of the present invention requires that the average reflectance at a wavelength of 400 to 800 nm is 80% or more, which is higher as the reflectance in the visible light region is higher. It is because the brightness | luminance of LED to perform tends to become high, and if it is the said range, it can utilize suitably as a coverlay film of the board | substrate for LED mounting. Moreover, since there exists a tendency for a brightness | luminance to become high so that the reflectance of 470 nm vicinity corresponding to the average wavelength (470 nm) of blue LED is high, it is more preferable that the reflectance in 470 nm is 80% or more, and a reflectance is 90%. More preferably, it is more preferably 95% or more.
Also, when obtaining white light using a currently mainstream blue LED, the reflectance near 470 nm is important. In order to obtain white light with higher color rendering properties, an ultraviolet (near ultraviolet) LED and a red LED are used. A combination of green, blue and phosphors has been developed. In that case, the coverlay film also reflects light with a wavelength of 350 to 400 nm corresponding to the emission wavelength of the ultraviolet (near ultraviolet) LED, and reflects light with a wavelength in the visible light region (400 to 800 nm). It becomes necessary to do.
Accordingly, the coverlay film of the first invention preferably has an average reflectance of 350 to 400 nm of 40% or more, more preferably 60% or more, and further preferably 80% or more.

[Resin layer containing thermoplastic resin (A)]
The cover lay film according to the first aspect of the present invention includes a resin layer (A) containing a thermoplastic resin, and examples of the thermoplastic resin include those shown below, and various inorganic materials. It may contain a filler or an additive.

(Thermoplastic resin)
Examples of the thermoplastic resin include polyether ether ketone (PEEK), polyether ketone (PEK), polyphenylene sulfide (PPS), polyether sulfone (PES), polyphenylene ether (PPE), polyamideimide (PAI), Examples include polyetherimide (PEI) and polyphenylsulfone (PPSU), and these may be used alone or in combination. Among these, for reasons of heat resistance, a crystalline thermoplastic resin having a crystal melting peak temperature of 260 ° C. or higher, an amorphous thermoplastic resin having a glass transition temperature of 260 ° C. or higher, and a liquid crystal having a liquid crystal transition temperature of 260 ° C. or higher. It is preferable to use at least one selected from polymers, a crystalline thermoplastic resin having a crystal melting peak temperature (Tm) of 260 ° C. or higher, and an amorphous thermoplastic having a glass transition temperature (Tg) of 260 ° C. or higher. It is more preferable to use at least one selected from resins. By using a thermoplastic resin in the above range, it is possible to have heat resistance against Pb-free solder reflow. In addition, it is possible to prevent oxidative deterioration in a high heat environment and suppress a decrease in reflectance. Crystalline thermoplastic resins having a crystal melting peak temperature of 260 ° C. or higher include polyether ether ketone (PEEK: Tg = 145 ° C., Tm = 335 ° C.), polyether ketone (PEK: Tg = 165 ° C., Tm = 355 ° C.). Polyaryl ketones (PAr), polyphenylene sulfide (PPS: Tg = 100 ° C., Tm = 280 ° C.) and the like are preferably used. As the amorphous thermoplastic resin having a glass transition temperature of 260 ° C. or higher, polyamideimide (PAI: Tg = 280 ° C.), polyetherimide (PEI) having a high Tg of 260 ° C. or higher, and the like are preferably used.

  This polyaryl ketone resin is a thermoplastic resin having an aromatic nucleus bond, an ether bond and a ketone bond in its structural unit, and representative examples thereof include polyether ketone, polyether ether ketone, polyether ketone ketone and the like. Of these, polyetheretherketone is preferred. Polyether ether ketone is commercially available as “PEEK151G”, “PEEK381G”, “PEEK450G” (all are trade names of VICTREX), and the like.

  This crystalline thermoplastic resin may be used alone, or a mixed resin composition obtained by mixing a plurality of crystalline thermoplastic resins may be used. Moreover, you may use the mixed resin composition which mixed amorphous thermoplastic resins, such as polyetherimide (PEI), with this crystalline thermoplastic resin. Among them, a resin composition comprising a crystalline polyaryl ketone resin (A) having a crystal melting peak temperature of 260 ° C. or higher and 80 to 20% by weight and an amorphous polyetherimide resin (B) 20 to 80% by weight. More preferably, it is used. By using this resin composition, it becomes possible to ensure extremely good adhesion to a substrate (hereinafter also simply referred to as “substrate”) on which an LED, which will be described later, is mounted. Has heat resistance.

  As a mixing ratio of the polyaryl ketone resin and the amorphous polyetherimide resin, considering the adhesion to the substrate, the polyaryl ketone resin is contained in an amount of 20% by mass to 80% by mass, and the balance is amorphous. It is preferable to use a mixed composition containing a polyetherimide resin and inevitable impurities. More preferably, they are 30 mass% or more and 75 mass% or less, More preferably, they are 40 mass% or more and 70 mass% or less. By setting the upper limit of the content of the polyaryl ketone resin within the above range, it is possible to suppress the increase in crystallinity of the thermoplastic resin constituting the coverlay film, and to prevent a decrease in adhesion to the substrate. Can do. Moreover, by setting the lower limit of the content of the polyaryl ketone resin within the above range, it is possible to prevent the crystallinity of the thermoplastic resin composition constituting the cover lay film from being lowered, and to prevent a decrease in heat resistance. be able to.

  The polyaryl ketone resin (A) is a thermoplastic resin having an aromatic nucleus bond, an ether bond and a ketone bond in its structural unit. Specific examples thereof include polyether ketone (glass transition temperature [hereinafter referred to as “Tg”]: 157 ° C., crystal melting peak temperature (hereinafter referred to as “Tm”]: 373 ° C.), polyether ether ketone (Tg: 143 C, Tm: 334 ° C.), polyether ether ketone ketone (Tg: 153 ° C., Tm: 370 ° C.), and the like. Among these, from the viewpoint of improving the heat resistance, it exhibits crystallinity and preferably has a Tm of 260 ° C. or higher, particularly 300 to 380 ° C. Moreover, as long as the effect of this invention is not inhibited, you may contain a biphenyl structure, a sulfonyl group, etc., or another repeating unit.

Among the polyaryl ketone resins (A), a polyaryl ketone resin (A) mainly composed of a polyether ether ketone having a repeating unit represented by the following structural formula (1) is particularly preferably used. Here, the main component means that the content exceeds 50% by mass. Commercially available polyether ether ketones are trade names “PEEK151G” (Tg: 143 ° C., Tm: 334 ° C.), “PEEK381G” (Tg: 143 ° C., Tm: 334 ° C.), “PEEK450G” manufactured by VICTREX. (Tg: 143 ° C., Tm: 334 ° C.) and the like. In addition, polyaryl ketone-type resin (A) can be used individually or in combination of 2 or more types.

  Specific examples of the amorphous polyetherimide resin (B) include an amorphous polyetherimide resin having a repeating unit represented by the following structural formula (2) or (3).

  The amorphous polyetherimide resin having a repeating unit represented by the structural formula (2) or (3) is composed of 4,4 ′-[isopropylidenebis (p-phenyleneoxy)] diphthalic dianhydride and p- As a polycondensate with phenylenediamine or m-phenylenediamine, it can be produced by a known method. Commercially available products of these amorphous polyetherimide resins include “Ultem 1000” (Tg: 216 ° C.), “Ultem 1010” (Tg: 216 ° C.) or “Ultem CRS 5001” (Tg 226) manufactured by General Electric. Among them, an amorphous polyetherimide resin having a repeating unit represented by the structural formula (2) is particularly preferable. In addition, polyetherimide resin (B) can be used individually or in combination of 2 or more types.

(Inorganic filler)
Examples of the inorganic filler include talc, mica, mica, glass flake, boron nitride (BN), calcium carbonate, aluminum hydroxide, silica, titanate (potassium titanate, etc.), barium sulfate, alumina, kaolin, Examples include clay, titanium oxide, zinc oxide, zinc sulfide, lead titanate, zircon oxide, antimony oxide, and magnesium oxide. These may be added singly or in combination of two or more.

  Inorganic fillers are those whose surface is treated with silicone compounds, polyhydric alcohol compounds, amine compounds, fatty acids, fatty acid esters, etc. in order to improve dispersibility in thermoplastic resins. Can be used. Among them, those treated with a silicone compound (silane coupling agent) can be preferably used.

(Linear expansion coefficient of MD and TD)
The resin layer (A) containing the thermoplastic resin preferably has an average value of the linear expansion coefficient of MD and TD of 35 × 10 ⁻⁶ / ° C. or less. A more preferable range of the linear expansion coefficient is about 10 × 10 ⁻⁶ to 30 × 10 ⁻⁶ / ° C., although it varies depending on the type of substrate used, the circuit pattern formed on the front and back surfaces, and the laminated configuration. Further, the difference in linear expansion coefficient between MD and TD is preferably 20 × 10 ⁻⁶ / ° C. or less, more preferably 15 × 10 ⁻⁶ / ° C. or less, and further 10 × 10 ⁻⁶ / ° C. or less. Most preferably. By reducing the anisotropy (difference between the linear expansion coefficients of MD and TD) in this way, there is no problem of curling or warping on the larger linear expansion coefficient or insufficient dimensional stability.

  In consideration of prevention of curling in the lamination with the substrate and dimensional stability, a specific method for setting the value of the linear expansion coefficient within the above range is an average particle diameter of 15 μm or less and an average aspect ratio (average particle diameter / average thickness). ) A method using 30 or more fillers 1 can be mentioned. Examples of the filler 1 include synthetic mica, natural mica (mascobite, phlogopite, sericite, szolite, etc.), baked natural or synthetic Examples thereof include inorganic scaly (plate-like) fillers such as mica, boehmite, talc, illite, kaolinite, montmorillonite, vermiculite, smectite, and plate-like alumina, and scaly titanates. According to these fillers 1, the linear expansion coefficient ratio in the plane direction and the thickness direction can be kept low.

  The content of the filler 1 is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin. . By setting it as the said range, it is possible to reduce effectively the linear expansion coefficient of the coverlay film obtained to a desired range.

  In consideration of light reflectivity, it is preferable that the thermoplastic resin contains the inorganic filler 2 having a large refractive index difference from the thermoplastic resin. Specifically, calcium carbonate, barium sulfate, zinc oxide, titanium oxide, titanate, or the like having a refractive index of 1.6 or more is preferably used, and titanium oxide is particularly preferably used.

  The titanium oxide has a significantly higher refractive index than other inorganic fillers, and can increase the difference in refractive index from the thermoplastic resin. Therefore, the titanium oxide is less blended than when other fillers are used. Excellent reflectivity can be obtained in an amount. Even if the film is thinned, a coverlay film having high reflectivity can be obtained.

  The titanium oxide is preferably a crystalline titanium oxide such as anatase type or rutile type. Among them, a rutile type titanium oxide is preferable from the viewpoint of a large difference in refractive index from the base resin.

  Moreover, although the manufacturing method of a titanium oxide has a chlorine method and a sulfuric acid method, it is preferable to use the titanium oxide manufactured by the chlorine method from the point of whiteness.

  The titanium oxide is preferably one whose surface is coated with an inert inorganic oxide. By coating the surface of titanium oxide with an inert inorganic oxide, the photocatalytic activity of titanium oxide can be suppressed, and deterioration of the film can be prevented. As the inert inorganic oxide, it is preferable to use at least one selected from the group consisting of silica, alumina, and zirconia. When these inert inorganic oxides are used, a decrease in the molecular weight of the thermoplastic resin and yellowing can be suppressed during high temperature melting without impairing high reflectivity.

  In addition, in order to improve dispersibility in the resin composition, titanium oxide has at least one inorganic compound selected from the group consisting of siloxane compounds, silane coupling agents, etc., a polyol, polyethylene glycol, and the like. Those surfaced with at least one organic compound selected from the group are preferred. In particular, those treated with a silane coupling agent are preferable from the viewpoint of heat resistance.

  The particle size of titanium oxide is preferably 0.1 to 1.0 μm, more preferably 0.2 to 0.5 μm. If the particle size of titanium oxide is in the above range, the dispersibility in the resin composition is good, the interface with it is densely formed, and high reflectivity can be imparted.

  The content of titanium oxide is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and most preferably 25 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin. By setting it within the above range, good reflection characteristics can be obtained, and good reflection characteristics can be obtained even when the thickness of the film is reduced.

(Polyorganosiloxane)
The polyorganosiloxane is a substance having a siloxane skeleton represented by the following formula (1) and capable of causing a crosslinking reaction.

  Here, “R” in the above formula (1) is an alkyl group such as a methyl group or an ethyl group, a hydrocarbon group such as a vinyl group or a phenyl group, or a halogen-substituted hydrocarbon group such as a fluoroalkyl group. Specifically, polydimethylsiloxane in which “R” in formula (1) is all methyl groups, or a part of the methyl groups of polydimethylsiloxane is one or more of the above hydrocarbon groups or halogen-substituted hydrocarbon groups. And various polyorganosiloxanes substituted by. As the polyorganosiloxane used in the present invention, those polydimethylsiloxanes and various polyalkylsiloxanes can be used alone or in admixture of two or more.

The resin layer (B) containing polyorganosiloxane is preferably one that undergoes crosslinking by radiation. Cross-linking by radiation is a method in which heat is not applied and is suitable for this configuration.
Usually, curing by thermal crosslinking is performed by heating for several tens of minutes at, for example, 100 to 200 ° C., followed by heating at 200 to 300 ° C. for several hours and secondary curing is required. When a laminate with the resin layer (A) contained (simply referred to as a thermoplastic resin layer) is produced, the thermoplastic resin layer and the polyorganosiloxane layer may be peeled off due to the difference in linear expansion coefficient, or the adhesive strength May not be obtained, or wrinkles may enter the thermoplastic resin layer, which may cause problems when used as a printed wiring board for LED mounting. Further, when a highly heat-resistant crystalline resin is used as the thermoplastic resin layer, when polyorganosiloxane is thermally cured, crystallization proceeds depending on the curing temperature, and there is a concern that stackability may be reduced.

  The radiation can be an electron beam, X-ray, or γ-ray. These radiations are widely used industrially, can be easily used, and are energy efficient. Among these, it is preferable to use γ rays having almost no absorption loss and high permeability.

  A crosslinking reaction can be caused by irradiating the uncrosslinked resin layer (B) with γ rays. Since the crosslinking reaction can be advanced by irradiation with γ rays, the crosslinking reaction can be caused without using a crosslinking agent. As a result, it is possible to avoid the color change due to the crosslinking agent seen when crosslinking is performed using the crosslinking agent, and it is also possible to prevent residual by-products due to the reaction of the crosslinking agent, so it has excellent heat resistance and light resistance. It is possible to obtain a resin layer (B).

  The irradiation dose of γ rays is generally preferably 10 kGy to 150 kGy, although it depends on the type of radiation source. More preferably, it is 20 kGy to 100 kGy, and particularly preferably 30 kGy to 60 kGy.

  In addition, in selecting the irradiation dose, it is preferable to take into consideration the radiation resistance of the plastic film used as the thermoplastic resin layer and the process film in addition to the crosslinking density of the polyorganosiloxane. In this respect, the crystalline polyester resin is generally a substrate excellent in resistance to radiation and suitable for the process film of the present invention.

(Inorganic filler contained in polyorganosiloxane)
Examples of the inorganic filler contained in the polyorganosiloxane include the same inorganic filler as that of the resin layer (A) containing the thermoplastic resin described above. Among these, the above-described titanium oxide is preferably used. By using titanium oxide, it is possible to obtain a coverlay film having a high reflectance.
Also, in order to obtain white light, in addition to the current mainstream blue LED and yellow phosphor, there is a combination of ultraviolet LED and red, blue and green phosphors, but when reflection in the ultraviolet region is required It is preferable to use one or more inorganic fillers that absorb less ultraviolet light, such as alumina, barium sulfate, and titanate.

  The content of the titanium oxide or the inorganic filler that absorbs less ultraviolet light is preferably 10 parts by mass or more and 250 parts by mass or less, and 20 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the polyorganosiloxane. More preferably, it is most preferably 30 parts by mass or more and 75 parts by mass or less. By setting it within the above range, good reflection characteristics can be obtained, and good reflection characteristics can be obtained even when the thickness of the film is reduced.

(Additives, etc.)
The constituent components of the resin layer (A) containing the thermoplastic resin and the resin layer (B) containing the polyorganosiloxane and the inorganic filler are other than other resins and inorganic fillers to the extent that their properties are not impaired. These additives, for example, heat stabilizers, ultraviolet absorbers, light stabilizers, nucleating agents, colorants, lubricants, flame retardants and the like may be appropriately blended. Moreover, it does not restrict | limit especially as a preparation method of the resin composition which comprises the said resin layer (A) and the said resin layer (B), A well-known method can be used.
For example, (a) separately preparing a master batch in which various additives are mixed in a suitable base resin such as a thermoplastic resin or polyorganosiloxane at a high concentration (typically 10 to 60% by weight). , Adjusting the concentration to the resin to be used, mixing and mechanically blending using a kneader or extruder, etc., (b) using a kneader or extruder directly adding various additives to the resin to be used. The method of blending mechanically is mentioned. Among the above mixing methods, the method of preparing and mixing the master batch (a) is preferable from the viewpoint of dispersibility and workability.

(Reduction rate of reflectivity)
The coverlay film according to the first aspect of the present invention requires that the reflectance decrease rate at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes is 5% or less.

  The grounds for the above conditions are described below. When manufacturing an LED mounting substrate, a thermosetting process (100 to 200 ° C., several hours) of a sealing agent such as a conductive adhesive, epoxy, or silicone resin, a soldering process (Pb-free solder reflow, peak temperature 260 ° C., (Several minutes) and wire bonding process, and so on. Further, even in an actual use environment, development of high-brightness LEDs has progressed, the thermal load on the substrate tends to increase, and the LED element ambient temperature may exceed 100 ° C. in some cases. In the future, it will be important to maintain a high reflectance without discoloration even under such a high heat load environment. The wavelength 470 nm is the average wavelength of the blue LED.

  Therefore, if the rate of decrease in reflectivity at a wavelength of 470 nm under the above conditions (at 260 ° C. for 10 minutes) is 5% or less, it is possible to suppress the decrease in reflectivity in the manufacturing process. Since it is possible to suppress a decrease in reflectance during use, it can be suitably used for an LED mounting substrate. More preferably, it is 4% or less, more preferably 3% or less, and particularly preferably 2% or less.

(Thickness of coverlay film)
The coverlay film according to the first aspect of the present invention preferably has a thickness of 3 to 500 μm. More preferably, it is 10-300 micrometers, Furthermore, it is 20-150 micrometers. Within such a range, it can be suitably used as a coverlay film for protecting a conductor circuit of a chip LED mounting substrate used as a surface light source for a mobile phone backlight or a liquid crystal display backlight that is required to be thin. it can.

(Coverlay film forming method)
Examples of the film forming method of the cover lay film according to the first aspect of the present invention include known film forming methods. For example, the resin layer (A) containing a thermoplastic resin is extruded using a T-die. A method of forming a resin layer (B) containing a polyorganosiloxane and an inorganic filler by coating with a compound raw material, which is molded by a calender method or the like, and a polyorganosiloxane and an inorganic filler are stirred with a stirrer. And so on. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the composition, but is generally about the melting point or higher and 430 ° C. or lower. In addition, when a crystalline resin is used, a crystallization treatment method for imparting heat resistance is not particularly limited. For example, a method of crystallization at the time of extrusion casting (cast crystallization method) or film formation In-line crystallization using a heat treatment roll or hot-air furnace (in-line crystallization method), and out-of-film crystallization method using a hot-air furnace or hot press (outline crystallization method). it can.

(Laminated structure)
The coverlay film according to the first aspect of the present invention only needs to have at least a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler. Other layers such as an adhesive layer may be interposed between the (A) layer and the (B) layer or between the (B) layer and the substrate. In order to improve the adhesion to the polyorganosiloxane, the surface of the layer (A) may be subjected to corona treatment, UV treatment, plasma treatment or the like. A silane coupling agent or primer treatment may be performed.

<Light emitting element mounting substrate>
The light emitting element mounting substrate according to the second aspect of the present invention includes a resin layer (A) containing a thermoplastic resin, a polyorganosiloxane, and an inorganic filler on a substrate on which at least one light emitting element is mounted. The protective layer has a resin layer (B) to be formed, and the protective layer has an average reflectance at a wavelength of 400 to 800 nm of 80% or more and a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes. There is no particular limitation as long as the reflectance reduction rate is 5% or less, and the substrate on which the light-emitting element is mounted includes, for example, at least one surface of a substrate made of a thermosetting resin or a thermoplastic resin. Various wiring boards on which a light emitting element is mounted can be used after a predetermined conductor pattern is formed on a metal laminate in which a metal layer is laminated. On a known substrate on which such a light emitting element is mounted, a resin layer (A) containing a thermoplastic resin and a resin (B) containing a polyorganosiloxane and an inorganic filler having specific physical properties is provided. If a protective layer is formed, it becomes possible to protect the conductor circuit. Since the protective layer has a high reflectance, it also functions as a reflector and contributes to an improvement in the reflectance of the substrate. Is also possible.

(Metal layer)
As the metal layer, for example, a metal foil having a thickness of about 5 to 70 μm made of copper, gold, silver, aluminum, nickel, tin or the like can be used. Among these, as the metal foil, a copper foil is usually used, and a metal foil having a surface subjected to chemical conversion treatment such as black oxidation treatment is preferably used. In order to enhance the adhesive effect, it is preferable to use a conductor foil that has been chemically or mechanically roughened in advance on the contact surface (surface to be overlapped) side with the film. Specific examples of the conductor foil that has been subjected to surface roughening treatment include a roughened copper foil that has been electrochemically treated when an electrolytic copper foil is produced. As for the method of laminating the metal foil, a known method can be adopted as a heat fusion method without using an adhesive layer as long as it is a method using heating and pressurization. A roll method, an extrusion laminating method in which the cast resin is laminated with a cast roll, or a method combining these can be suitably employed.

  Also, if more heat dissipation is required for the substrate on which the light-emitting element is mounted, it must be combined with a metal material such as a copper plate or an aluminum plate, a ceramic such as aluminum nitride, or a material with high thermal conductivity such as a graphite plate. It is also possible to improve heat dissipation. For example, as a composite substrate structure with an aluminum plate, the above-mentioned metal laminate is laminated on the entire surface of the aluminum plate, or a window frame for a cavity (recess) structure is removed from the metal laminate and laminated. If you want to. The aluminum to be used is preferably roughened in consideration of the adhesion to the resin, but when considering the cavity structure, in order to efficiently reflect the light from the LED, highly reflective aluminum is used. It is preferable to use it. Examples of the highly reflective aluminum include those whose surfaces have been polished, those which have been anodized, and those which have been subjected to a reflection-reflecting film treatment by depositing an inorganic oxide such as titanium or silica, or a metal such as silver. The average reflectivity at 400 to 800 nm is preferably 80% or more, more preferably 90% or more, and particularly preferably high-reflective aluminum having 95% or more.

(Manufacturing method of light emitting element mounting substrate)
The method for producing the light emitting element mounting substrate according to the second invention is not particularly limited. In the case of a double-sided substrate in which metal layers are laminated on both sides, for example, according to the method shown in FIG. Can be manufactured. As shown in FIG. 1, (a) First, a substrate (100) made of a thermoplastic resin or a thermosetting resin and two copper foils (10) to be a metal layer are prepared, and (b) thermoplasticity. A copper foil (10) is laminated on both sides of a substrate (100) made of resin or thermosetting resin by vacuum pressing to produce a metal laminate, and (c) the copper foil (10) is etched or plated on copper. Then, a wiring pattern (20) is formed, and a substrate on which the light emitting element is mounted is manufactured. (D) A resin layer (30) containing a thermoplastic resin, and a resin layer (40) containing a polyorganosiloxane and an inorganic filler, in which a portion to be mounted is subjected to window processing on the substrate. The protective layer (200) provided is laminated at once (here, the cover lay film according to the first aspect of the present invention is laminated) to form a light emitting element mounting substrate. (E) After that, gold plating is performed, the LED (300) is mounted, connected to the wiring pattern (20) by the bonding wire (50), and sealed with a predetermined resin for use (light source device). In addition, the method for performing window cutting is not particularly limited, and a method using a big die, a router processing method, a laser processing method, and the like can be used. In addition to the above, in the formation of the protective layer, after laminating a resin layer (30) containing a film-like thermoplastic resin on a substrate, a resin layer containing a polyorganosiloxane and an inorganic filler ( 40) may be applied to form a protective layer.

  The light emitting element mounting substrate according to the second aspect of the present invention may be an aluminum composite substrate. For example, as shown in FIG. 2, a metal laminate is manufactured by laminating a copper foil (10) on one side of a substrate (100) made of a thermoplastic resin or a thermosetting resin, and (b) a copper foil. (10) is etched to form a wiring pattern (20), gold plating is performed, and the substrate (100) is punched into a cavity frame using a big die (60). 200) and the surface on which the wiring pattern (20) is formed, an aluminum plate (400) is laminated by vacuum pressing to form a light emitting element mounting substrate. (D) The LED (300) is mounted on this substrate, connected to the wiring pattern (20) with a bonding wire (50), and sealed and used with a predetermined resin (light source device). Note that the method of punching into the cavity frame is not limited to the method using the Bic die, and for example, it can be formed by router processing or using a laser. In addition, in the said manufacturing method, although lamination | stacking of the film with a single-sided copper foil ((b) in FIG. 2), a protective layer, and an aluminum plate is performed collectively, these are laminated | stacked sequentially, and frame extraction is carried out after that. A conductor pattern can also be formed.

<Light source device>
As the light source device according to the third aspect of the present invention, a conductor circuit is formed on the light emitting element mounting substrate according to the second aspect of the present invention, and the light emitting element mounted on the substrate is electrically connected to the light emitting element. It is not particularly limited as long as it is formed by resin-sealing, and by forming a protective layer, it becomes possible to effectively protect the conductor circuit, under high temperature heat load environment and light resistance Since the reflectance does not decrease even in a test environment, the light source device of the present invention is used in various applications such as lighting, projector light sources, backlight devices such as liquid crystal display devices, in-vehicle applications, and mobile phone applications. Can be used.

  Hereinafter, although an Example and a comparative example demonstrate in more detail, this invention is not limited to these. In addition, the various measured values and evaluation about the film etc. which are shown in this specification were calculated | required as follows.

[Crystal melting peak temperature (Tm)]
Using a differential scanning calorimeter “DSC-7” (manufactured by PerkinElmer), the temperature was determined from a thermograph when 10 mg of a sample was heated at a heating rate of 10 ° C./min according to JIS K7121.

[Average reflectance]
An integrating sphere is attached to a spectrophotometer ("U-4000", manufactured by Hitachi, Ltd.), and the reflectance when the reflectance of the alumina white plate is 100% is measured at intervals of 0.5 nm over a wavelength range of 400 nm to 800 nm. did. The average value of the measured values obtained was calculated, and this value was taken as the average reflectance.

[Reflectance after heat treatment]
The obtained white film was fixed with a fixing jig, heated in a hot air circulation oven at 260 ° C. for 10 minutes, the reflectance after the heat treatment was measured in the same manner as described above, and the reflectance at 470 nm was read. It was.

[Measurement of linear expansion coefficient]
Using a thermal stress strain measuring device TMA / SS6100 manufactured by Seiko Instruments Inc., a strip-shaped test piece (length 10 mm) cut out from the film of the resin layer (A) is fixed with a tensile load of 0.1 g, 30 The temperature is increased from 300 ° C. to 300 ° C. at a rate of 5 ° C./min, and the temperature dependency of MD (α1 (MD)) and TD (α1 (TD)) at 30 ° C. to 140 ° C. when the temperature decreases is obtained. It was.

[Average particle size]
Using a powder specific surface measuring instrument (transmission method) of model “SS-100” manufactured by Shimadzu Corporation, a sample tube having a cross-sectional area of 2 cm ² and a height of 1 cm was filled with 3 g of sample, and 20 cc with a 500 mm water column. The air permeation time was measured, and the average particle size of titanium oxide was calculated from this.

  Produced by the chlorine method with respect to 100 parts by mass of a resin mixture consisting of 40% by mass of polyetheretherketone resin (PEEK450G, Tm = 335 ° C.) and 60% by mass of amorphous polyetherimide resin (Ultem 1000). A resin composition obtained by mixing 30 parts by mass of titanium oxide (average particle diameter 0.23 μm, alumina treatment, silane coupling agent treatment), 21 parts by mass of synthetic mica having an average particle diameter of 5 μm and an average aspect ratio of 50. A film having a thickness of 50 μm was produced at a set temperature of 380 ° C. using an extruder equipped with a melt-kneading and a T-die. Thereafter, a resin composition obtained by mixing 100 parts by mass of polyorganosiloxane (TSE 2913U, manufactured by Momentive) and 67 parts by mass of titanium oxide (R105, manufactured by DuPont) with a planetary mixer was set using an extruder. Extruded into a 100 μm thick film on a release PET film at a temperature of 100 ° C. Thereafter, the release PET film was peeled off and laminated on the layer made of the thermoplastic resin to obtain a coverlay film. Then, it hardened with the irradiation dose of 50 kGy by the gamma ray.

  In Example 1, a coverlay film was produced in the same manner as in Example 1, except that 150 parts by mass of alumina (“AA04” manufactured by Sumitomo Chemical Co., Ltd.) was filled in the polyorganosiloxane and the thickness was 100 μm.

  A coverlay film was produced in the same manner as in Example 1 except that polyorganosiloxane (“TSE2571-5U” manufactured by Momentive) was used.

[Comparative Example 1]
A coverlay film was produced in the same manner as in Example 1 except that the resin layer (B) containing the polyorganosiloxane and the inorganic filler was not provided.

As can be seen from the results shown in Table 1, in Examples 1 to 3, it was possible to obtain a coverlay film having little reflectance change, dimensional stability, and reflectance change after the heating test. Particularly in Examples 1 and 3, since the polyorganosiloxane was filled with titanium oxide, a particularly high reflectance was shown in the visible light region (400 to 800 nm).
In Example 2, since the polyorganosiloxane is filled with alumina, the reflectance in the visible light region is high, but the reflectance in the ultraviolet light region (350 to 400 nm) is also improved.
On the other hand, in Comparative Example 1, since the resin layer containing the polyorganosiloxane and the inorganic filler was not provided, the reflectance in the visible light region was inferior.

10 Copper Foil 20 Wiring Pattern 30 Resin Layer Containing Thermoplastic Resin (A)
40 Resin layer containing polyorganosiloxane and inorganic filler (B)
50 Bonding wire 100 Substrate 200 made of thermoplastic resin or thermosetting resin Protective layer 300 LED
400 aluminum plate

Claims (9)

A resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler,
Cover for protecting a conductive circuit of a printed wiring board having an average reflectance at a wavelength of 400 to 800 nm of 80% or more and a reduction rate of the reflectance at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes being 5% or less Ray film.   The thermoplastic resin is selected from a crystalline thermoplastic resin having a crystal melting peak temperature of 260 ° C. or higher, an amorphous thermoplastic resin having a glass transition temperature of 260 ° C. or higher, and a liquid crystal polymer having a liquid crystal transition temperature of 260 ° C. or higher. The coverlay film according to claim 1, which is at least one of them.   The coverlay film according to claim 1 or 2, wherein the resin layer (B) is cured by radiation.   The coverlay film according to claim 1, wherein the inorganic filler contains at least titanium oxide. The coverlay film according to any one of claims 1 to 4, wherein an average value of linear expansion coefficients of MD and TD of the resin layer (A) containing the thermoplastic resin is 35 x ^10-6 / ° C or less.   The coverlay film according to claim 1, wherein the film has a thickness of 3 to 500 μm.   The coverlay film according to any one of claims 1 to 6, wherein an average reflectance at a wavelength of 350 to 400 nm is 40% or more. A protective layer having a resin layer (A) containing a thermoplastic resin and a resin layer (B) containing a polyorganosiloxane and an inorganic filler is formed on a substrate on which at least one light emitting element is mounted. Become
The protective layer has an average reflectance of 80% or more at a wavelength of 400 to 800 nm, and a reduction rate of reflectance at a wavelength of 470 nm after heat treatment at 260 ° C. for 10 minutes is 5% or less. Device mounting board.   9. A light source comprising: a light-emitting element mounting substrate according to claim 8; a conductive circuit formed on the substrate; the substrate and the light-emitting element mounted on the substrate are electrically connected; and the light-emitting element sealed with a resin. apparatus.

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