JP2005109402A - Laser module and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a contaminant in a sealed container for obtaining satisfactory characteristics and reliability in a laser module, where a semiconductor laser device is installed in the sealed container. <P>SOLUTION: An adhesive composition is inserted between at least one optical component (for example, the semiconductor laser device 6) in the sealed container 2 and a fixing member (for example, a submount 5) for fixing the optical component so that adhesion thickness becomes ≥0.05 μm and ≤5 μm before curing is made by an active energy ray for fixing the optical component 6 to the fixing member 5. In this case, the adhesive composition contains an alicyclic epoxy compound having an epoxy group, a compound having an oxetanyl group, and an onium salt photoreaction initiator for catalyst quantity. A substance 11 having gas adsorption function is arranged in the sealed container 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser module in which a semiconductor laser element is installed in an airtight container, and a method for manufacturing the same.

  Conventionally, a laser module in which a semiconductor laser element, a collimator lens, a condenser lens, an optical fiber, and the like are sealed in an airtight container is known. In this type of laser module, a problem has been recognized that contaminants remaining in the hermetically sealed container adhere to optical components such as the emission end face of the semiconductor laser element, lenses, and optical fibers, thereby degrading laser characteristics. Examples of the pollutants include hydrocarbon compounds mixed in from the atmosphere of the manufacturing process, and it is known that the hydrocarbon compounds are polymerized or decomposed by laser light and adhered.

  In order to solve this problem, various methods have been proposed as described below. For example, in Patent Document 1, it is effective to reduce the amount of the hydrocarbon compound in the container to 0.1% or less in order to prevent a decrease in the output of laser light having a wavelength of 400 nm or less. It is described that deposition on an optical component or the like due to photodecomposition can be prevented. In addition, it has been proposed that the sealing atmosphere be dry air, and an effect of removing the deposit by a photochemical reaction between oxygen in the atmosphere and the deposited hydrocarbon compound is expected.

  In Patent Document 2, in order to prevent the attachment of a hydrocarbon compound to the end face of the semiconductor laser element due to the photolysis of a hydrocarbon gas, oxygen for the purpose of decomposing this gas is 100 ppm or more in sealing gas. It is described that it is mixed in.

  Patent Document 3 describes that long-term reliability can be ensured by degreasing and washing away contaminants such as oil.

On the other hand, Patent Document 4 proposes a laser module using a GaN-based semiconductor laser element having an oscillation wavelength of 350 to 450 nm. However, in this type of laser module, a short wavelength laser beam has high energy. The hydrocarbon gas present in the module is polymerized or decomposed, which has a high probability of adhering to the end face of the semiconductor laser element or the optical component, which is a particular problem.
Japanese Patent Laid-Open No. 11-167132 U.S. Pat.No. 5,392,305 Japanese Patent Laid-Open No. 11-87814 Japanese Patent Laid-Open No. 2002-202442

The hydrocarbon-based deposit generated by the reaction between the laser beam and the hydrocarbon compound is decomposed into CO ₂ and H ₂ O in a gas atmosphere containing a certain amount or more of oxygen as shown in Patent Document 2 above. Is eliminated.

  However, it is confirmed that not only hydrocarbon compounds but also silicon compounds are present in this kind of deposit, and it is impossible to decompose and remove this kind of deposit only by containing oxygen in the atmosphere. I understand. The deposited silicon compound is generated by a photochemical reaction between an organic compound gas containing Si such as a siloxane bond (Si—O—Si) or a silanol group (—Si—OH) (hereinafter referred to as an organosilicon compound) and laser light. Moreover, the presence of oxygen in the atmosphere has the effect of increasing the reaction rate. Since the deposits of hydrocarbon compounds and silicon compounds generate optical absorption, there is a problem that the reliability over time in continuous oscillation is significantly impaired.

  In addition, the silicon compound said here shows what has all the structures containing silicon regardless of organic and inorganic, and contains inorganic SiOx and an organosilicon compound.

  The generation source is a gas emitted mainly from a silicone-based material used at an arbitrary place in the laser module manufacturing process. This may be adhered to the surface of each component in the laser module, and when the module is used in a sealed state, it is contained in a small amount in the sealing gas. Examples of a method for removing gas components in these processes include normal clean room operation and installation of a sealing gas purifier, but even these methods cannot be completely removed, Large capital investment is required. Further, even through a degreasing process such as oil as disclosed in Patent Document 3, it is unavoidable that the compound is mixed from the manufacturing process atmosphere as described above.

  The hydrocarbon compound and silicon compound-based gas adhering to the components in the laser module can be removed by decomposition and evaporation by heat treatment at a temperature of 200 ° C. or higher, preferably 300 ° C. or higher. However, this heat treatment requires a processing time of several to several tens of hours, and when fixing the components in the module with an organic adhesive, the mechanical properties deteriorate due to the thermal deterioration of the adhesive, so this method is used. I can't.

  In view of the above circumstances, an object of the present invention is to provide a highly reliable laser module in which contaminants are satisfactorily removed in a laser module in which a semiconductor laser element is disposed in an airtight container.

  Another object of the present invention is to provide a method by which the laser module as described above can be manufactured with high durability.

The laser module of the present invention is a laser module in which a semiconductor laser element is installed in a sealed container.
An alicyclic epoxy compound having an epoxy group, a compound having an oxetanyl group, and a catalytic amount of an onium salt photoinitiator are provided between at least one optical component in the sealed container and a fixing member that fixes the optical component. After inserting the adhesive composition containing, the optical component is fixed to the fixing member by curing with active energy rays,
A substance having a gas adsorption function is arranged in the sealed container.

  The adhesive composition inserted between the optical component and the fixing member is preferably inserted so that the adhesive thickness is 0.05 μm or more and 5 μm or less.

  The substance having a gas adsorption function arranged in the container is preferably at least one of a zeolite adsorbent and activated carbon.

  The laser module of the present invention may include an optical fiber and an optical system for inputting laser light from the semiconductor laser element into the sealed container in a sealed container.

  The oscillation wavelength of the semiconductor laser element constituting the laser module of the present invention is preferably 450 nm or less.

  On the other hand, it is desirable that the adhesive composition contains a silane coupling agent.

  Furthermore, the adhesive composition desirably contains spherical silica particles having an average diameter of 0.1 μm or more and 1.0 μm or less.

  The fixing member is preferably made of a metal member, and the optical component is preferably made of an inorganic transparent member.

Moreover, it is preferable that the compound which has the said oxetanyl group is what is represented by following General formula (1).

In the formula (1), R ₁ represents a methyl group or an ethyl group, and R ₂ represents a hydrocarbon group having 6 to 12 carbon atoms.

  On the other hand, a method for manufacturing a laser module according to the present invention is a method for manufacturing the above-described laser module according to the present invention, in which an epoxy is interposed between at least one optical component in the sealed container and a fixing member for fixing the optical component. An alicyclic epoxy compound having a group, a compound having an oxetanyl group, and a catalytic amount of an onium salt photoinitiator, having a viscosity at room temperature of 10 mPa · s to 1,000 mPa · s, The adhesive composition having a contact angle with the body of 40 degrees or less is inserted so that the adhesion thickness is 0.05 μm or more and 5 μm or less, and then cured by active energy rays.

  The adhesive composition used in the present invention is described in detail in JP-A-2001-177166, but will be described in detail below.

  This adhesive composition contains an alicyclic epoxy compound having an epoxy group, a compound having an oxetanyl group, and a catalytic amount of an onium salt photoinitiator as essential components. These compounds and initiators may be either one kind or a mixture of two or more kinds.

  In the present invention, an epoxy compound having two or more epoxy groups in one molecule can be used. As the epoxy compound, two or more epoxy groups in one molecule and an alicyclic structure are provided. An alicyclic epoxy compound having two or more epoxy groups in one molecule is preferably used rather than a glycidyl compound that does not. “A cycloaliphatic epoxy compound having an epoxy group” means one molecule of a partial structure obtained by epoxidizing a cycloalkene ring double bond such as a cyclopentene group or a cyclohexene group with an appropriate oxidizing agent such as hydrogen peroxide or peracid. A compound having two or more in it. The alicyclic epoxy compound having an epoxy group of the present invention is preferably a compound having two or more cyclohexene oxide groups or cyclopentene oxide groups in one molecule. Specific examples of such alicyclic epoxy compounds include 4-vinylcyclohexylene dioxide, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate, di (3,4-epoxycyclohexyl) adipate. , Di (3,4-epoxycyclohexylmethyl) adipate, bis (2,3-epoxycyclopentyl) ether, di (2,3-epoxy-6-methylcyclohexylmethyl) adipate, and dicyclopentadiene dioxide. One type of alicyclic epoxy compound having an epoxy group may be used, or a mixture of two or more types may be used. Various alicyclic epoxy compounds are commercially available and can be obtained from Union Carbide Japan Co., Ltd., Daicel Chemical Industries, Ltd., and the like.

  Further, a glycidyl compound having two or more epoxy groups in one molecule and having no alicyclic structure can be used in combination with the alicyclic epoxy compound in an amount of substantially equal to or less than the same weight. Examples of such glycidyl compounds include glycidyl ether compounds and glycidyl ester compounds, but it is preferable to use glycidyl ether compounds in combination. Specific examples of the glycidyl ether compound include 1,3-bis (2,3-epoxypropyloxy) benzene, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac. Glycidyl ether compounds such as epoxy resins, trisphenolmethane epoxy resins, aliphatic glycidyl ethers such as 1,4-butanediol glycidyl ether, glycerol triglycidyl ether, propylene glycol diglycidyl ether, and trimethylolpropane tritriglycidyl ether Compounds. Examples of the glycidyl ester include glycidyl ester of linolenic acid dimer. The glycidyl compound used in combination with the alicyclic epoxy compound may be one kind or a mixture of two or more kinds. Glycidyl ethers are commercially available from Yuka Shell Epoxy Co., Ltd.

  The compound having an oxetanyl group (hereinafter also simply referred to as “oxetane compound”) is a compound having one or more oxetanyl groups in one molecule. This oxetanyl group-containing compound is roughly classified into a compound having one oxetanyl group in one molecule and a compound having two or more oxetanyl groups in one molecule.

As the monofunctional oxetane compound having one oxetanyl group in one molecule, a compound represented by the following general formula (1) is preferable.

In the formula (1), R ₁ represents a methyl group or an ethyl group, and R ₂ represents a hydrocarbon group having 6 to 12 carbon atoms. The hydrocarbon group for R ₂ may be a phenyl group or a benzyl group, but is preferably an alkyl group having 6 to 8 carbon atoms, particularly preferably a branched alkyl group such as a 2-ethylhexyl group. Examples of oxetane compounds in which R ₂ is a phenyl group are described in JP-A-11-140279. An example of an oxetane compound which is a benzyl group in which R ₂ may be substituted is described in JP-A-6-16804. The oxetane compound in which R ₁ is an ethyl group and R ₂ is a 2-ethylhexyl group is preferably used in the present invention as an excellent diluent, curing accelerator, flexibility imparting agent, and surface tension reducing agent. .

In the present invention, a polyfunctional oxetane compound having two or more oxetanyl groups in one molecule can be used, but a preferred compound group is represented by the following general formula (2).

In formula (2), m represents a natural number of 2, 3 or 4, and Z represents an oxygen atom, a sulfur atom or a selenium atom. R ₃ is a hydrogen atom, a fluorine atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a fluoroalkyl having 1 to 6 carbon atoms, an allyl group, a phenyl group or a furyl group. R ₄ is an m-valent linking group, preferably a group having 1 to 20 carbon atoms, and may contain one or more oxygen atoms and sulfur atoms. Z is preferably an oxygen atom, R ₃ is preferably an ethyl group, m is preferably 2, and R ₄ is preferably a linear or branched alkylene group having 1 to 16 carbon atoms or a linear or branched poly (alkyleneoxy) group. Further preferred are compounds in which any two or more of the preferred examples for R ₃ , R ₄ , Z and m are combined.

  The onium salt photoinitiator used in the present invention refers to an onium salt that is considered to generate active chemical species by irradiating an adhesive composition with active energy rays. As the onium salt photoreaction initiator, aromatic iodonium salts, aromatic sulfonium salts and the like are preferable because they are thermally relatively stable. Here, the active energy ray is an energy ray that can generate a chemically active species (cationic species such as Lewis acid, Bronsted acid, etc.) that can act on an onium salt to initiate a chemical reaction, and is capable of producing ultraviolet rays, electron beams, and the like. , Gamma rays, X-rays and the like, but ultraviolet rays are preferably used.

When an aromatic sulfonium salt and an aromatic iodonium salt are used as an onium salt photoinitiator, the counter anions include BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ , PF ₆ ⁻ , B (C ₆ F ₅ ) _4- ^{and the} like. As the initiator, PF ₆ salt or SbF ₆ salt of aromatic sulfonium can be preferably used since it has solubility and moderate polymerization activity. In order to improve the solubility, one or more alkyl groups or alkoxy groups having 1 to 10 carbon atoms are introduced into the aromatic group, usually phenyl group, of the aromatic group iodonium salt or aromatic sulfonium salt. A chemical structure is preferred. PF ₆ salt or SbF ₆ salt of aromatic sulfonium salt is commercially available from Union Carbide Japan Co., Ltd. Asahi Denka Kogyo Co., Ltd. also sells PF ₆ salt of aromatic sulfonium under the trade name of Adekaoptomer SP series. The aromatic sulfonium salt has absorption up to about 360 nm, and the aromatic iodonium salt has absorption up to about 320 nm. Therefore, in order to cure the aromatic sulfonium salt, it is preferable to irradiate ultraviolet rays including spectral energy in this region.

Among the chemical structural formulas shown below, sulfonium salts PI-3 and PI-4 are preferably used because of their high light absorption efficiency.

  The onium salt photoinitiator used in the present invention generates an active cationic species by the action of an active energy ray, and cationically polymerizes an alicyclic epoxy compound and a compound having an oxetanyl group, whereby the adhesion of the present invention. It is considered to cure the adhesive composition.

  In the adhesive composition used in the present invention, the weight ratio of the alicyclic epoxy compound and the oxetane compound is (95 to 65) parts by weight (5 to 35) parts by weight, preferably (80 to 70) parts by weight. Parts by weight (20 to 30) parts by weight. If the monofunctional oxetane compound is too small, the liquid properties such as the viscosity and surface tension of the adhesive composition are not good, and conversely if the monofunctional oxetane compound is added too much, the cured product becomes too flexible and the adhesive strength. Decreases. The onium salt photoinitiator may be used in a catalytic amount, and the addition amount is 0.3 to 10 parts by weight with respect to 100 parts by weight of the total of the alicyclic epoxy compound and the oxetane compound. The preferred range is 5 parts by weight.

  In the present invention, the adhesive composition is inserted between the optical component and the fixing member so that the adhesive thickness is 0.05 μm or more and 5 μm or less. Below this adhesive thickness, the adhesive strength is insufficient, and above this thickness, the adhesive shrinkage tends to be adversely affected. An adhesion thickness of 0.05 μm or more and 2 μm or less is preferable, and an adhesion thickness of 0.2 μm or more and 1 μm or less is particularly preferable.

  In the present invention, it is preferable to further add a silane coupling agent to the adhesive composition. The silane coupling agent is considered to have a property of chemically bonding an optical component and an adherent inorganic member or metal member to the adhesive composition. By using this silane coupling agent in combination, the adhesive strength and the adhesive durability can be improved. As the silane coupling agent used in combination with the present invention, epoxy silanes having an epoxy group and a trimethoxysilyl group in one molecule are preferably used. Such a coupling agent is available from Shin-Etsu Chemical Co., Ltd. under trade names such as KBM303, KBM403, and KBE402. The preferred use range of the silane coupling agent is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the total of the alicyclic epoxy compound and the oxetane compound.

  In the present invention, it is preferable that spherical particles are contained in the adhesive composition. The silica particles preferably have a diameter of 0.1 μm to 2 μm and have a particle size distribution as uniform as possible. Particles having an average particle size of 0.2 μm or more and 0.8 μm or less are preferably used in the present invention, and silica particles having a nearly spherical shape and few ionic impurities are particularly preferably used. The thermal durability of the cured adhesive composition can be improved by adding the silica particles. The addition amount of the spherical silica particles can be appropriately selected within the range of 1 to 20 parts by weight with respect to 100 parts by weight of the adhesive composition. Synthetic quartz spherical silica is commercially available from Tatsumori Co., Ltd.

  In the present invention, the adhesive composition is preferably used for adhesion between an inorganic transparent member such as a lens and a reflection mirror and a metal fixing member such as a metal (copper, copper alloy, aluminum, etc.) holder that adheres and fixes the same. The

  As a result of intensive studies, the inventor preferably adjusts the viscosity at room temperature (25 ° C.) of the adhesive composition to 10 mPa · s or more and 1,000 mPa · s or less, and the viscosity is 80 mPa · s or more and 300 mPa · s. It is further preferable to adjust to the following, and in addition, it is preferable that the contact angle between the adhesive composition and the adherend is 40 degrees or less, more preferably 30 degrees or less to provide good adhesive fixation. I found it. In order to adjust the composition viscosity, the addition of a monofunctional oxetane compound is effective. If necessary, the contact angle can be adjusted by adding a fluorosurfactant. Fluorosurfactants are surfactants having fluorocarbon as a hydrophobic group, and there are three types of anions, cations, and nonions. In the present invention, the use of fluorinated alkyl ester nonionic surfactants is possible. preferable. The addition amount of this nonionic surfactant is 0.1 to 1 part by weight with respect to 100 parts by weight of the adhesive composition. This nonionic surfactant is commercially available from Sumitomo 3M Co., Ltd. under the trade name of FLORARD (FC170C, 171 430, 431, etc.).

  In addition to the above additives, inert components such as dyes and pigments can be appropriately added to the adhesive composition used in the present invention. In addition, for the purpose of improving photocurability, a photosensitizer such as pyrene, perylene, acridine orange, thioxanthone, 2-chlorothioxanthone, and benzopyran may be added. Various light sources can be used as the ultraviolet light source for curing with ultraviolet rays, and examples thereof include mercury arc lamps, xenon arc lamps, carbon arc lamps, and tungsten-halogen copying lamps.

  According to the laser module of the present invention, the hydrocarbon compound and the silicon compound are favorably adsorbed by arranging the substance having the gas adsorption function in the sealed container in which the semiconductor laser element is installed. These compounds are not deposited on the emission end face or the like of the semiconductor laser element, and the laser characteristics and reliability can be improved. In addition, since it is not necessary to perform heat treatment, a highly reliable semiconductor laser element can be efficiently manufactured.

  Further, unlike the prior art, there is no need to adjust the atmosphere of the sealed space or to perform degreasing and cleaning treatment, and the module manufacturing process can be simplified.

  In particular, when at least one of a zeolite adsorbent and activated carbon is used as a substance having a gas adsorption function, hydrocarbon compounds and the like can be adsorbed satisfactorily, so that laser characteristics and reliability are further improved. Can be.

  Furthermore, if the present invention is applied to a laser module further provided with an optical fiber, it is possible to effectively prevent contamination from being deposited on the surface of the optical system member and the input end of the optical fiber. is there.

  In particular, in the case of a semiconductor laser element having an oscillation wavelength of 450 nm or less, the deposition rate and the deposition amount of hydrocarbon compounds by these short wavelength laser beams are larger than those in the case of long wavelength laser beams, so the present invention is applied. It is very effective.

  In the present invention, when the above-mentioned adhesive composition is used for bonding the optical component and the fixing member, the curing shrinkage rate (linear shrinkage rate) when the adhesive is cured can be suppressed to about 2%. Therefore, when optical components such as a semiconductor laser element, a collimator lens, a condenser lens, and an optical fiber constituting the laser module are fixed to the fixing member by the adhesive composition, the layer thickness of the adhesive composition is 5 μm or less. If adjusted, even if curing shrinkage of the uncured portion of the adhesive composition proceeds, the shrinkage can be suppressed to an extremely low level of about 5 × 0.02 = 0.1 μm. Further, the above-mentioned adhesive composition penetrates uniformly even when the distance between the optical component and the fixing member is as narrow as about 1 μm, and generates a strong and flexible cured product even after curing with ultraviolet rays or the like. Therefore, adhesion without occurrence of peeling can be realized in a wide temperature range from low temperature (−25 ° C.) to high temperature (70 ° C.). As described above, since the relative positional accuracy of the optical components as described above is kept high, the laser module of the present invention can be provided with high reliability also in this respect.

  On the other hand, in the method for producing a laser module of the present invention, an alicyclic epoxy compound having an epoxy group, a compound having an oxetanyl group, between at least one optical component in a sealed container and a fixing member for fixing the same, And a catalytic amount of an onium salt photoinitiator, having a viscosity at room temperature of 10 mPa · s to 1,000 mPa · s (more preferably 80 mPa · s to 300 mPa · s), An adhesive composition having a contact angle of 40 degrees or less (more preferably 30 degrees or less) is inserted so that the adhesion thickness is 0.05 μm or more and 5 μm or less, and then cured by active energy rays. Therefore, as described above, good adhesive fixation can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A can-type sealed laser module according to the first embodiment of the present invention will be described. FIG. 1 shows a schematic configuration diagram of the laser module, FIG. 2 (a) shows a schematic plan view, and FIG. 2 (b) shows a schematic side view.

As shown in FIG. 1, the laser module according to the present embodiment includes a heat sink 4 in which a semiconductor laser element 6 is bonded onto a submount 5, an electrode terminal 8 connected from the semiconductor laser element 6 by a wire 9, and an electrode. A monitoring photodiode 10 connected to a terminal 12 by a wire 13 is fixed on the stem 1, and further, one zeolite adsorbent 11 is fixed with an inorganic adhesive, The container 2 having the glass window 3 provided with the reflective coating is ring-welded sealed in a dry air (N ₂ = 80%, O ₂ = 20%) atmosphere. The internal volume of the container 2 is 67.5 mm ³ .

  The zeolite adsorbent 11 is installed on the stem 1 between the wall surface of the container 2 and the heat block 4 as shown in FIGS. 2 (a) and 2 (b). As shown in FIG. 2 (c), the zeolite adsorbent 11 was molded into a cylindrical shape having a diameter (x) of 1.5 mm and a height (y) of 1.5 mm. The installation location of the zeolite adsorbent is not limited to the above location, and may be any location in the container as long as it does not interfere with laser oscillation.

The zeolite adsorbent 11 is preferably “Zeoram F9 HA” manufactured by Tosoh Corporation, and this “Zeolam F9 HA” is a crystalline hydrous aluminosilicate (Me / x · Al) of an alkali metal or alkaline earth metal. ₂ O ₃ · mSiO ₂ · nH ₂ O: Me is an x-valent metal ion). The amount of the zeolite adsorbent 11 is desirably determined in consideration of the internal volume of the container, the estimated amount of contaminants, the adsorption capacity of the adsorbent 11, and the like.

  In this embodiment, an inorganic adhesive is used as an adhesive for adhering the zeolite adsorbent 11. However, either an organic adhesive or an inorganic adhesive may be used.

  Further, FIG. 1 does not show the front half of the cylindrical container 2 in order to facilitate understanding of the component configuration in the container.

  The can-type sealed laser module according to the present embodiment emits the laser light 7 that is the front emission light of the semiconductor laser element 6 from the window glass 3 that is coated without reflection, and the rear emission light of the semiconductor laser element 6. The monitor photodiode 10 senses the amount of light emission, and the current is automatically controlled so that the output of the laser beam 7 is constant.

  Next, the temporal reliability of the laser module according to the present invention and the conventional laser module was evaluated. FIG. 3 shows a graph of change over time in the drive current in the conventional laser module, and FIG. 4 shows a graph of change in drive current over time in the laser module of the present invention. The vertical axis of the graph is a value obtained by normalizing the drive current with the initial drive current.

As the laser module according to the present invention, the laser module according to the first embodiment, in which the oscillation wavelength of the semiconductor laser element 6 is 405 nm, is used. As the conventional laser module, the same laser module as in the first embodiment was used except that the zeolite adsorbent 11 was not provided. Both the conventional example and the sealing atmosphere in the laser module of the present invention are dry air (N ₂ = 80%, O ₂ = 20%). The evaluation was carried out by adjusting the drive current so that the light output was 30 mW at an environmental temperature of 25 ° C.

  In the laser module of the conventional example, as shown in FIG. 3, a change in driving current is seen over time, but in the laser module of the present invention, as shown in FIG. 4, no increase in driving current is seen and stable over time. doing. Therefore, by incorporating the adsorbent in the module, it is possible to satisfactorily prevent contaminants such as hydrocarbon compounds from adhering to the end face of the semiconductor laser element or optical components, and to obtain stable laser characteristics. I understood that I could do it.

Next, adhesion of the semiconductor laser element 6 to the submount 5 which is a fixing member made of a metal such as copper will be described. The adhesive surface of the semiconductor laser element 6 was brought into close contact with the adhesive surface of the submount 5 and an adhesive composition described in detail below was inserted into the gap, and then cured by ultraviolet irradiation. Union Carbide Japan Co., Ltd. UVR6128 (bis (3,4-epoxycyclohexyl) adipate) was used as the alicyclic epoxy compound, and Aron Oxetane OXT-212 (EHOX) from Toa Gosei Co., Ltd. was used as the monofunctional oxetane compound. And UVI-6990 (PF5 salt of triarylsulfonium) manufactured by Union Carbide Japan Co., Ltd. was used as a photoinitiator, and the weight ratio of these components was set as shown in Table 1 below. Then, adhesive composition Examples 1 to 3 and Comparative Example 1 were prepared.

  After the adhesive composition was cured by UV irradiation, the adhesion uniformity was visually observed with an optical microscope. The adhesives of Examples 1 to 3 combined with the oxetane compound EHOX were compared with the adhesive of Comparative Example 1 that was not used in combination. Also showed excellent uniformity of the adhesive surface.

  Next, a laser module according to the second embodiment of the present invention will be described. A schematic side view and top view of the laser module are shown in FIG.

  In the laser module according to the present embodiment, as shown in FIG. 5, a base plate 42 is fixed to the bottom surface of the container 40, and seven GaN-based semiconductor laser elements LD21 to LD27 are bonded onto the base plate 42. The heat block 20, the collimator lenses 31 to 37 held by the collimator lens holder 44 attached to the heat block 20, the condenser lens 43 held by the condenser lens holder 45, and the fiber holder 46. The multimode optical fiber 30 is fixed. An opening is formed in the wall surface of the container 40, and a wiring 47 for supplying a driving current to the GaN-based semiconductor laser elements LD21 to LD27 is drawn out of the container through the opening.

The container 40 is provided with a lid 41 made so as to close its opening, and a columnar zeolite adsorbent 50 having a diameter of 1.5 mm and a height of 1.5 mm is provided in a region 51 on the back surface of the lid 41. It is fixed with an inorganic adhesive in an array of 120, 10 × 12. After the semiconductor laser element and the optical member are arranged in the container, the container 40 is sealed with a lid 41 adhered in a dry air (N ₂ = 80%, O ₂ = 20%) atmosphere. The internal volume of the container 40 was 8160 mm ³ , and “Zeoram F9 HA” manufactured by Tosoh Corporation was used as the zeolite adsorbent 50 as in the first embodiment.

  Each of the collimator lenses 31 to 37 is formed in a shape obtained by cutting an area including the optical axis of a circular lens having an aspherical surface into a long and narrow plane. This elongated collimator lens can be formed, for example, by molding resin or optical glass. The collimator lenses 31 to 37 are closely arranged in the arrangement direction of the light emitting points so that the length direction is orthogonal to the arrangement direction of the light emitting points of the GaN-based semiconductor laser elements LD21 to LD27.

  In FIG. 5 (a), in order to avoid complication of the drawing, only the semiconductor laser elements LD21 and LD27 among the plurality of GaN-based semiconductor laser elements are denoted by reference numerals, and the collimator lens 31 among the plurality of collimator lenses. Only 37 and 37 are labeled.

  On the other hand, each of the GaN-based semiconductor laser elements LD21 to LD27 includes an active layer having an emission width of 2 μm, and each laser has a divergence angle of 10 ° or 30 ° in a direction parallel to or perpendicular to the active layer, respectively. Lasers that emit beams B21 to B27 are used. These semiconductor laser elements LD21 to LD27 are arranged so that the light emitting points are aligned in a direction parallel to the active layer.

Therefore, in the laser beams B21 to B27 emitted from the respective light emitting points, the direction in which the divergence angle is large with respect to the elongated collimator lenses 31 to 37 coincides with the length direction as described above, and the direction in which the divergence angle is small. Is incident in a state that coincides with the width direction (direction orthogonal to the length direction). That is, the collimator lenses 31 to 37 have a width of 1.1 mm and a length of 4.6 mm, and the horizontal and vertical beam diameters of the laser beams B21 to B27 incident thereon are 0.9 mm and 2. 6 mm. Each of the collimator lenses 31 to 37 has a focal length f ₁ = 3 mm, NA = 0.6, and a lens arrangement pitch = 1.25 mm.

The condensing lens 43 is formed by cutting a region including the optical axis of a circular lens having an aspherical surface into a long and narrow plane parallel to the arrangement direction of the collimator lenses 31 to 37, that is, horizontally long and short in a direction perpendicular thereto. Is formed. The condenser lens 43 has a focal length f ₂ = 12.5 mm and NA = 0.3. This condensing lens 43 is also formed by molding resin or optical glass, for example.

  The multimode optical fiber 30 may be any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber. For example, a graded index optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. This optical fiber has a graded index at the center of the core and a step index at the outer periphery, the core diameter = 25 μm, NA = 0.3, and the transmittance of the end coat = 99.5% or more.

  The laser beams B21 to B27 are condensed by the condenser lens 43 and incident on the multimode optical fiber 30, where they are combined with each other, increased in output, and emitted from the multimode optical fiber 30.

  Also in the second embodiment, as in the first embodiment, it is confirmed that the drive current does not increase with time and is stable.

  When an organic adhesive is used for adhering the adsorbent, an organic gas component generated from the adhesive is present in the module. In Japanese Patent Application No. 2002-101714, it has been proposed to remove an organic gas or the like by degassing. In the laser module according to the second embodiment, the diameter is 1.5 mm, the height is 1. If 150 columnar zeolite adsorbents 11 each having a diameter of 5 mm are incorporated, the organic gas and the like can be favorably adsorbed by the adsorbent even if sealing is performed without performing a deaeration process. Therefore, good laser characteristics and reliability over time can be obtained without increasing the manufacturing process and manufacturing cost.

Next, adhesion of the collimator lenses 31 to 37 to the collimator lens holder 44 which is a fixing member made of metal such as copper will be described. The adhesive surface of the collimator lenses 31 to 37 (the lower end surface in FIG. 5B) is brought into close contact with the adhesive surface of the collimator lens holder 44, and an adhesive composition described in detail below is inserted into the gap, followed by ultraviolet rays. Cured by irradiation. Union Carbide Nippon Co., Ltd. UVR6128 is used as the alicyclic epoxy compound, and bisphenol F-type Epicoat 806 manufactured by Yuka Shell Epoxy Co., Ltd. is used as the bifunctional glycidyl compound, and the monofunctional oxetane compound as Toa. Aron Oxetane OXT-212 (EHOX) of Synthetic Co., Ltd. is used in combination as necessary, and UVI-6990 (PF5 salt of triarylsulfonium) manufactured by Union Carbide Japan Co., Ltd. is used as a photoinitiator. As a silane coupling agent, KBE303 manufactured by Shin-Etsu Chemical Co., Ltd. and synthetic quartz spherical silica 1-FX (average particle size 0.38 μm) manufactured by Tatsumori Co., Ltd. are used in combination as necessary. The weight ratio was set as shown in Table 2 below, and adhesive composition examples 4 to 10 were prepared.

  After the adhesive composition was cured by ultraviolet irradiation and subjected to a storage test at −25 ° C. to 70 ° C., the peel occurrence rate of the adhesive surface was measured, and the results shown in Table 2 were obtained. Examples 5 and 6 using an adhesive composition with an increased amount of the monofunctional oxetane compound EHOX show lower peeling rates than Example 4, and further Examples 7 and 6 using an adhesive combined with a silane coupling agent No. 8 was further reduced in the occurrence rate of peeling, and no peeling was observed particularly in Example 8. Example 9 is an embodiment in which a bisphenol F-type diglycidyl compound is optionally used in combination with an alicyclic epoxy compound, and Example 10 is an embodiment in which synthetic quartz spherical silica is optionally added. However, in any case, no peeling occurred between the collimator lens holder 44 and the adhesive layer even in the forced storage test.

  Further, after the adhesive composition was cured by irradiating ultraviolet rays, the layer thickness of each adhesive between the collimator lens holder 44 and the collimator lenses 31 to 37 was measured. It was 6 μm. This adhesive had a volume hardening shrinkage of 4 to 5%, and the thickness change of each adhesive layer after a storage test at -25 ° C to 70 ° C was suppressed to 0.03 µm or less. Therefore, the relative positional relationship between the GaN-based semiconductor laser elements LD21 to LD27 and the collimator lenses 31 to 37 whose optical axes have been adjusted does not go out of alignment due to the adhesion, and a good multiplexing effect can be obtained.

  Note that the bonding method as described above includes bonding between the other optical components in the container 40 and the fixing member, for example, bonding between the condensing lens 43 and the condensing lens holder 45, and the multimode optical fiber 30 and the fiber holder 46. In this case, the same effects as described above are basically obtained.

  Further, the bonding method as described above is not limited to the laser device shown as the first and second embodiments, but generally includes optical components such as a light source, a lens, a mirror, a half mirror, a concave mirror, a convex mirror, and a diffraction grating. In an optical device, the present invention can be widely applied to bonding and fixing these optical components and their fixing members, and even in such a case, the same effects as described above are basically obtained.

  In the first and second embodiments, the zeolite adsorbent is used as the adsorbent. However, activated carbon or both zeolite adsorbent and activated carbon may be used, as in the case of the zeolite adsorbent. The effect of can be obtained. Even when activated carbon is used, it may be fixed in the container using an inorganic or organic adhesive. You may use the adsorption agent which consists of another compound as a substance which has a gas adsorption function.

  According to the present invention, contaminants such as a hydrocarbon compound existing in a container in which a semiconductor laser element is sealed can be satisfactorily removed, so that a highly reliable laser module can be provided.

1 is a schematic configuration diagram showing a laser module according to a first embodiment of the present invention. Plan view and side view showing the laser module A graph showing changes in drive current over time in a conventional laser module The graph which shows the time-dependent change of the drive current in the laser module by the 1st Embodiment of this invention. The schematic block diagram which shows the laser module by the 2nd Embodiment of this invention.

Explanation of symbols

1 Stem 2 Lid 3 Window Glass 4 Heat Sink 5 Submount 6 Semiconductor Laser Element 7 Laser Light 8 Electrode Terminal 9 Wire
10 Monitor photodiode
11 Zeolite adsorbent
12 Electrode terminal
13 wires
30 Multimode optical fiber
31-37 Collimator lens
40 containers
43 condenser lens
44 Collimator lens holder
45 Condenser lens holder
LD21 to LD27 GaN-based semiconductor laser device

Claims (9)

In a laser module in which a semiconductor laser element is installed in a sealed container,
An alicyclic epoxy compound having an epoxy group, a compound having an oxetanyl group, and a catalytic amount of an onium salt photoinitiator are provided between at least one optical component in the sealed container and a fixing member that fixes the optical component. After inserting the adhesive composition containing, the optical component is fixed to the fixing member by curing with active energy rays,
A laser module, wherein a substance having a gas adsorption function is disposed in the sealed container.   2. The laser module according to claim 1, wherein the substance having a gas adsorption function is at least one of a zeolite adsorbent and activated carbon.   3. The laser module according to claim 1, further comprising: an optical fiber and an optical system for inputting laser light from the semiconductor laser element into the sealed container.   4. The laser module according to claim 1, wherein an oscillation wavelength of the semiconductor laser element is 450 nm or less.   The laser module according to claim 1, wherein the adhesive composition contains a silane coupling agent.   6. The laser module according to claim 1, wherein the adhesive composition contains spherical silica particles having an average diameter of 0.1 μm to 1.0 μm.   The laser module according to claim 1, wherein the fixing member is made of a metal member, and the optical component is made of an inorganic transparent member. The laser module according to claim 1, wherein the compound having an oxetanyl group is represented by the following general formula (1).

In the formula (1), R ₁ represents a methyl group or an ethyl group, and R ₂ represents a hydrocarbon group having 6 to 12 carbon atoms.   9. The method for producing a laser module according to claim 1, wherein an alicyclic epoxy compound having an epoxy group between at least one optical component in the sealed container and a fixing member for fixing the optical component. , A compound having an oxetanyl group, and a catalytic amount of an onium salt photoreaction initiator, having a viscosity at room temperature of 10 mPa · s to 1,000 mPa · s, and a contact angle with the adherend of 40 ° A method for producing a laser module, comprising: inserting an adhesive composition as described below so that an adhesion thickness is 0.05 μm or more and 5 μm or less, and then curing with an active energy ray.

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