JP2008217859A - Protective film for optical pickup photodetector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective film for an optical pickup photodetector by which an adhesive is not left on a substrate and a photodetector of an optical pickup device, when the protection film is peeled after a solder reflow process is performed, in a state such that the surfaces of the substrate and the photodetector are protected by the protective film comprising a heat resistant film with an adhesive layer. <P>SOLUTION: In the protective film having a layered structure, wherein a release film formed by providing a release adhesive layer on an organic film is formed on a surface of the adhesive layer, provided on the heat resistant resin film so that the release adhesive layer is adjacent to the surface of the adhesive layer, each of the adhesive layer and the release adhesive layer contains a silicone component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a protective film for an optical pickup light receiving element for protecting a light receiving element of an optical pickup device on a substrate.

An optical pickup device is used for reproducing and recording an optical disc such as a CD (compact disc) or a DVD (digital versatile disc). The manufacturing process of the optical pickup device includes the steps of fixing and mounting an LSI chip component on the first flexible substrate by soldering, the step of soldering and connecting the second flexible substrate on the first flexible substrate, and the second flexible substrate. Adjusting and adhering various optical components and light receiving elements, connecting the second flexible substrate to the first flexible substrate, attaching a metal cover on the first and second flexible substrates, and finally A check step is performed (see, for example, Patent Document 1).

Each part of the optical pickup device can be connected by heat treatment. A protective film is laminated on the substrate holding the light receiving element in order to prevent the solder, adhesive or the like used for the use from adhering to the light receiving element during the heat treatment. As this protective film, a film that can withstand heat treatment by soldering, for example, an adhesive tape in which a cured product of a silicone adhesive composition is directly laminated on a polyimide film can be used (see, for example, Patent Document 2). .
However, the adhesive tape of the above prior art is applied to protect the substrate made of silicone resin and the light receiving element, and after mounting by solder reflow and peeling, there is a problem that adhesive residue is generated on these substrate and light receiving element. Had. In particular, when adhesive residue is generated on a light receiving element made of silicone resin, transmission of light used for information transmission is hindered, leading to a decrease in sensitivity of the light receiving element, and thus malfunction of a device using the light receiving element. There was a risk of causing.

As an optical pickup device using a light receiving element made of a silicone resin to which the present invention is applied, CD, DVD, and Blu-ray and HD DVD which are attracting attention as next-generation DVDs, which are about 780 nm and about 650 nm, respectively. , Using a wavelength of about 405 nm. Any of these optical pickup devices incorporating a silicone resin light receiving element can mount a heat-resistant resin film on the light receiving element by solder reflow according to the present invention. As a result, it is possible to prevent solder, adhesive, or the like from adhering to the light receiving element during mounting. Moreover, if this heat-resistant resin film can transmit all of the above wavelengths satisfactorily, the light-receiving element detects these wavelengths while the heat-resistant resin film is stuck on the light-receiving element. It can be checked whether or not. If the protective film according to the present invention is used, adhesive residue on the light receiving element can be prevented even after the unnecessary protective film is peeled off after this inspection.

JP 2006-202367 A JP 2004-190013 A

In the present invention, after the solder reflow treatment is performed in a state where the surface of the substrate or the light receiving element of the optical pickup device is protected with a protective film made of a heat resistant film with an adhesive layer, the protective film is peeled off, and then the paste is applied to the substrate or the light receiving element. It is an object of the present invention to provide a protective film for an optical pickup light-receiving element that does not cause the remainder.

The present invention has a laminated structure in which a release film in which a release adhesive layer is provided on an organic film is provided on the surface of an adhesive layer provided on a heat resistant resin film so that the release adhesive layer is adjacent to the adhesive film. The protective film for an optical pickup light receiving element, wherein the layer and the release adhesive layer contain a silicone component (claim 1).

The heat resistant resin film is preferably epoxy acrylate. (Claim 2). Moreover, it is preferable that the said adhesion layer contains a filler (Claim 3).

According to the protective film for an optical pickup light receiving element of the present invention (hereinafter referred to as a protective film), the protective film can be easily peeled from a substrate such as a silicone resin even after a solder reflow process which is a high temperature mounting process. . Accordingly, no adhesive residue is generated on the substrate, and therefore, it can be suitably used even in a silicone substrate having a light receiving element.

If epoxy acrylate is used for the heat resistant resin film of the protective film of the present invention, the transmittance at a wavelength of 400 to 800 nm is 80% or more. Accordingly, it is possible to check whether or not these light receiving elements can detect a specific wavelength in a state where the heat resistant resin film is provided on the light receiving elements of CD, DVD, and next generation DVD.

Hereinafter, although more preferable embodiment of this invention is described, this invention is not necessarily limited to this at all.
FIG. 1 is a cross-sectional view of the protective film of the present invention. That is, the heat-resistant resin film 1 has a structure in which the release film 3 composed of the adhesive layer 2, the release adhesive layer 3-1, and the organic film 3-2 is sequentially laminated. The method for producing the protective film of FIG. 1 of the present invention is produced, for example, by applying the adhesive layer 2 on the heat resistant resin film 1 and removing the solvent of the adhesive layer 2 and then laminating the release film 3. The

The surface which peeled the peeling film 3 from the adhesion layer 2 turns into a surface which sticks to the board | substrate 5 (FIG. 2). The adhesive layer 2 only needs to be laminated on the substrate 5 and may be laminated on the entire substrate 5 as shown in FIG. 2 or on a part of the substrate 5. The area may be designed as appropriate.
The substrate 5 may use a glass plate or a light receiving element made of silicone resin, or may have a light receiving element inside the substrate 5 even if the light receiving element is sealed. Also good. The number of light receiving elements may be one or more, and the number is not particularly limited. Moreover, a hole can be provided in the substrate 5, and a light receiving element may be provided in the hole. The number of holes may be one or two or more, and is not particularly limited.

<Heat resistant resin film>
The heat-resistant resin film used in the present invention only needs to have a property that does not substantially deform after the solder reflow treatment. The solder reflow treatment in the present invention means that a resin film placed on a metal mesh (7 mm-interval mesh) is placed on a small nitrogen reflow furnace (manufactured by Asahi Electronics) and heated for a total of 4 minutes. The fact that the resin film is not substantially deformed means that there is no change in the shape before and after the solder reflow process, and there are slight undulations along the metal mesh. Means what you can do. The small nitrogen reflow furnace moves sequentially from zone 1 to zone 4 at a speed of 0.3 m / min, and the ambient temperature in each zone is not particularly limited, but may be in the range of 210 to 260 ° C. It can be suitably evaluated.

Specifically, a polyimide film, an epoxy acrylate resin film, or the like can be suitably used as the heat-resistant resin film having properties that do not substantially deform after the solder reflow treatment. In particular, the epoxy acrylate resin film is preferable because the transmittance at wavelengths of 400 to 800 nm is 80% or more. Examples of the epoxy acrylate resin include a vinyl ester resin obtained by reacting a general bisphenol-type or alicyclic epoxy compound with (meth) acrylic acid, and in particular, the vinyl ester resin and the vinyl compound or allyl. A resin obtained by curing a mixture of one or more monomers selected from compounds and a polymerization initiator with light and / or heat is preferably used.

The vinyl ester resin is a vinyl ester resin produced by reacting a bisphenol type or alicyclic epoxy compound with (meth) acrylic acid. As the epoxy resin, a reaction product of bisphenol A and epichlorohydrin, bisphenol F and Reaction product of epichlorohydrin, reaction product of hydrogenated bisphenol A and epichlorohydrin, reaction product of cyclohexanedimethanol and epichlorohydrin, reaction product of norbornane dialcohol and epichlorohydrin, reaction product of tetrabromobisphenol A and epichlorohydrin, tricyclodecanedimethanol and epichlorohydrin Reactant, Alicyclic Diepoxy Adipate, Alicyclic Diepoxy Carbonate, Alicyclic Diepoxy Acetal, Alicyclic Diepoxy Shi carboxylate and the like.

Moreover, as a vinyl compound and an allyl compound, general things, such as an allyl ester monomer, an acrylic acid ester monomer, a methacrylic acid ester monomer, a styrene monomer, (alpha) -methylstyrene monomer, an acrylonitrile monomer, can be used, for example. Specifically, as the allyl ester monomer, diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, diallyl 1,4-cyclohexanedicarboxylate, diallyl succinate or the like can be used. Examples of acrylic acid ester monomers and methacrylic acid ester monomers include methyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, EO adduct dimethacrylate of bisphenol A, and EO of bisphenol A. Adduct diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, phenoxyethyl methacrylate, isobornyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxy Ethyl methacrylate, trimethylolpropane di Chlorate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane tris-oxyethylene acrylate, trimethylolpropane tris-oxyethylene methacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipenta Erythritol hexaacrylate, glycerin diacrylate, glycerin dimethacrylate, 2,6-dibromo-4-tertiary butylphenyl acrylate, and the like can be used.

In order to cure the heat resistant resin used in the present invention, photocuring and thermosetting are useful. Examples of the photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, and 2-methyl-1- (4-methylthiophenyl) -2. -Monofolinopropane-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 and the like. In the case of thermosetting, organic peroxides such as dialkyl peroxides, acyl peroxides, hydroxy peroxides, ketone peroxides, and peroxy esters are used.

The heat resistant resin film constituting the present invention preferably has a glass transition temperature of 70 ° C. or higher. When the glass transition temperature is less than 70 ° C., the heat resistance is poor. Moreover, it is preferable that it is 10-300 micrometers, and, as for the thickness of the resin film in this invention, it is more preferable that it is 20-200 micrometers. More preferably, it is 25-50 micrometers. If the thickness is less than 10 μm, it is difficult to peel off from the substrate after being attached to the substrate by solder reflow via an adhesive, and a wave is likely to occur. On the other hand, when it exceeds 300 μm, it becomes difficult to peel off from the substrate. In addition, the glass transition temperature in this invention means the value measured with the differential scanning calorimeter (DSC).

The heat resistant resin film constituting the present invention preferably has a retardation at 590 nm of 3 nm or less. The retardation means a value obtained using a phase difference measuring device (product name: KOBRA-WR manufactured by Oji Scientific Instruments).

The heat-resistant resin film made of an epoxy acrylate resin used in the present invention is a glass having high smoothness by thoroughly mixing a vinyl ester resin and one or more monomers selected from vinyl compounds or allyl compounds and a polymerization initiator. It can be obtained by sandwiching with a substrate such as, and curing by applying heat or light (UV light).

<Adhesive layer>
The pressure-sensitive adhesive layer constituting the protective film of the present invention contains a silicone component. As the silicone component, any of silicone oil, silicone varnish, and silicone resin can be applied to the present invention, and an adhesive layer can be produced by applying the silicone component on a heat resistant resin film. The heating temperature and heating time can be appropriately selected.

The thickness of the adhesive layer of the present invention is preferably 10 μm or less. More preferably, it is 5 μm or less. If it is 10 micrometers or less, it will become easy to peel from a board | substrate after sticking an adhesion layer and a board | substrate by solder reflow.

Additives can be appropriately mixed in the pressure-sensitive adhesive layer of the present invention. For example, by containing a filler, the filler will be present at the interface between the adhesive layer and the substrate, and the adhesive force between the adhesive layer and the substrate can be reduced. The adhesive residue is less likely to occur. Moreover, in the protective film which laminated | stacked the adhesion layer containing the additive on the heat resistant resin film, if the transmittance | permeability in 400-800 nm is 80% or more, it is preferable.

<Peeling film>
The release film constituting the protective film of the present invention is not limited as long as the release adhesive layer 3-1 containing a silicone component is laminated on the organic film 3-2 as shown in FIG. The types of components and organic film are not particularly limited. As the silicone component, any of silicone oil, silicone varnish and silicone resin can be used in the present invention. The organic film may have a low heat resistance. Specifically, for example, a polyethylene terephthalate film can be used.
The release film types are a light release film, a middle release film, and a heavy release film in order from the largest amount of the silicone component contained in the release adhesive layer, but any of them may be used. Use of a light release film is preferable because it easily peels from the adhesive layer.

Examples of the substrate to which the protective film of the present invention is suitably applied include a substrate containing silicone and / or made of silicone. You may use the light receiving element made from silicone, or a thing which has a light receiving element in a silicone substrate. The surface shape of these substrates is not particularly limited, and may be smooth or uneven.
Hereinafter, the present invention will be described by way of examples.

A heat resistant resin film was produced as follows.
The following materials were added to a 1 liter flask equipped with a thermometer, stirrer, fractionation condenser and gas inlet tube.
・ Bisphenol A diepoxy compound 374.4g
・ Methacrylic acid 206.4g
・ Chromium octylate 1.5g
・ Phosphorous acid 0.15g
・ Hydroquinone 0.2g
Thereafter, the reaction was carried out at 120 to 125 ° C. for 2 hours while blowing nitrogen gas into the flask. Thereafter, when the acid value reached 11.0, the flask contents were transferred to a metal vat and cooled to obtain Resin A.

Next, a monomer material and the like were uniformly dissolved and mixed with the resin A at the following blending ratio to prepare a mixture, which was defoamed with a vacuum defoamer.
Resin A 70 parts by weight Methyl methacrylate 10 parts by weight Styrene 20 parts by weight N-nitrosophenylhydroxyamine aluminum salt 0.003 parts by weight 1,1,3,3-trimethylbutylperoxy-2-ethylhexanate 1.5 parts by weight

Next, the above-mentioned mixture was filled in two flat glass plates having a polyethylene terephthalate (PET) film having a thickness of 100 μm sandwiched at the four corners, and the mixture was placed in an oven at 130 ° C. for 5 minutes for curing. Further, after cooling at room temperature, the glass was removed to prepare a heat-resistant resin film (film thickness 100 μm, glass transition temperature 96 ° C., retardation 1.5 nm).

On the above heat-resistant resin film, 100 parts by weight of silicone adhesive (main agent (trade name: SD4600FC manufactured by Toray Dow Corning), 0.9 parts by weight of catalyst (trade name: NC-25cat manufactured by Toray Dow Corning) , A curing agent (trade name: BY24-741 manufactured by Toray Dow Corning Co., Ltd., 1.5 parts by weight, mixed with 50 parts by weight of toluene) is applied, dried at 150 ° C. for 5 minutes, thickness 2 An adhesive layer of ˜3 μm was formed. A protective film of Example 1 was obtained by laminating a silicone release film (trade name: PET5001 manufactured by Lintec Corporation) obtained by applying a silicone varnish to a polyethylene terephthalate film on the adhesive layer.

[Comparative Example 1]
A protective film of Comparative Example 1 was used in the same manner as in Example 1 except that a fluorine release film (trade name: PET380010YA manufactured by Fujimori Kogyo Co., Ltd.) was used instead of the release film having the release adhesive layer of the silicone component. .

In addition, the glass transition temperature of the heat resistant resin film used by the said Example and comparative example means the value which measured with the differential scanning calorimeter (DSC). Moreover, the retardation of the said Example and a comparative example means the value obtained using the phase difference measuring apparatus (Oji Scientific Instruments company product name: KOBRA-WR) in 590 nm.

<Embodiment 1>
The release film constituting the protective film obtained in Example 1 and Comparative Example 1 was peeled off, and the exposed surface of the adhesive layer was bonded to a glass plate. Moreover, the peeling film of the protective film of Example 1 was peeled, and the exposed adhesive layer was sufficiently washed with toluene, and bonded to a glass plate as Reference Example 1.

The laminates of Example 1, Comparative Example 1, and Reference Example 1 were treated in an oven at 220 ° C. for 10 minutes and then allowed to cool sufficiently at room temperature. Next, with a Tensilon universal testing machine (product name: RTC-1210A manufactured by ORIENTEC), the heat-resistant resin film with an adhesive layer constituting these laminates was formed from the glass surface under the condition of full scale 2N (2%). It peeled and the adhesive force of the adhesion layer and the glass surface was measured. Subsequently, the adhesive residue on the glass surface after the adhesion measurement was visually confirmed. The judgment criteria were “◯” when no adhesive residue was observed, “X” when adhesive residue was observed, and “XX” where peeling was not possible from the glass surface.
Moreover, when the solder reflow process was performed using these, in any case, the heat-resistant resin film did not substantially deform.

As shown in Table 1, when the silicone component-containing release film was laminated on the silicone component-containing adhesive layer, the adhesive strength did not increase before and after the heating, and no adhesive residue was generated on the glass. On the other hand, Comparative Example 1 using a fluorine release film instead of the silicone component-containing release film does not increase the adhesive strength before and after the heating, but the adhesive strength after heating is as high as 60 g. It occurred. Moreover, in the thing of Example 1, the reference example 1 which wash | cleaned the surface of the silicone adhesion layer which peeled the silicone peeling film increased the adhesive force after a heating, and was not able to peel from glass. This phenomenon supports the unexpected effect of not causing adhesive residue due to the interaction between the silicone component of the release film and the surface of the adhesive layer on the heat-resistant resin film.

FIG. 1 is a view showing a protective film according to the present invention. FIG. 2 is a diagram showing an embodiment in which the protective film according to the present invention is attached to a substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat resistant resin film 2 Adhesive layer 3 Peeling film 3-1 Peeling adhesive layer 3-2 Organic film 4 Protective film 5 Substrate

Claims (3)

The pressure-sensitive adhesive layer provided on the heat-resistant resin film has a laminated structure in which a release film formed by providing an organic film with a release adhesive layer is provided adjacent to the release adhesive layer. A protective film for an optical pickup light receiving element, wherein the layer contains a silicone component. The protective film for an optical pickup light receiving element according to claim 1, wherein the heat resistant resin film is an epoxy acrylate resin. The protective film for an optical pickup light receiving element according to claim 1, wherein the adhesive layer contains a filler.

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