JP2012079827A - Semiconductor light emitting device and light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently radiate joule heat generated by a semiconductor light emitting element to the exterior of a package while maintaining the airtightness of a metal cover sealing the semiconductor light emitting element.SOLUTION: A semiconductor light emitting device 1 includes a semiconductor light emitting element 3, a package 10 holding the semiconductor light emitting element 3, and a metal cover 21 fastened to the package 10 and sealing the semiconductor light emitting element 3. The package 10 has a base 11 and a weld base 12 formed on a main surface of the base 11 and resistance welding the metal cover 21. The coefficient of thermal conductivity of a first metal material forming the base 11 is larger than the coefficient of thermal conductivity of a second metal material forming the metal cover 21. Further, the difference in the coefficient of thermal conductivity between the base 11 and the weld base 12 is smaller than the difference in the coefficient of thermal conductivity between the base 11 and the metal cover 21.

Description

  The present invention relates to a semiconductor light emitting device and a light source device having a high intensity of emitted light used for a display such as a projector.

  In recent years, a semiconductor laser device having a high light output exceeding 1 W has been used as a light source for an image display device such as a laser display or a projector, or as a light source for an industrial processing device such as a laser scribing device or a thin film annealing device. Semiconductor light emitting devices have been actively developed. As an example of such a semiconductor light emitting device, for example, a semiconductor light emitting device in which a semiconductor light emitting element such as a semiconductor laser element is fixed to a base made of metal and sealed with a cap member provided with a glass window is as follows. Is disclosed in Japanese Patent Application Laid-Open No. H10-228707.

  Hereinafter, a conventional semiconductor light emitting device will be described with reference to FIG. As shown in FIG. 23, a conventional semiconductor light emitting device 300 includes a semiconductor laser element 301, a package 320 for holding the semiconductor laser element 301, a semiconductor laser element 301 covering the semiconductor laser element 301, and being fixed to the package 320. It is comprised from the cap member 330 which seals 301. FIG.

  The package 320 is provided on a base (stem) 321 made of an iron (Fe) -based material, a block portion (heat sink) 322 made of oxygen-free copper fixed thereon, and a base 321 in the front-back direction. The lead pins 324 and 325 are fixed to the through holes 321a and 321b through insulating rings 326 made of glass, respectively, and the lead pins 323 are directly fixed to the back surface of the base 321.

  The semiconductor laser element 301 is fixed to the block portion 322 via the submount 302 and is electrically connected to the lead pins 324 and 325 by two wires 327 and 328, respectively.

  The cap member 330 includes a metal cover made of Kovar (Kovar: Fe—Ni—Co alloy), and a light transmission window 334 made of optical glass and the like fixed with soft glass. The metal cover includes a cylindrical side wall portion 331, a top surface portion 332 in which one end of the side wall portion 331 is closed and an emission hole 332 a for extracting laser light from the semiconductor laser element 301 to the outside is formed. A flange portion 333 formed at the end and resistance-welded to the upper surface of the base 321 on which the semiconductor laser element 301 is held is provided. The light transmission window 334 is fixed to the inside of the top surface portion 332 so as to block the emission hole 332a.

  As a fixing method in the case where such a semiconductor light emitting device is used as a light source, for example, a configuration as disclosed in Patent Document 2 is disclosed.

  Next, a conventional method for fixing a semiconductor light emitting device will be described with reference to FIG. The fixing jig 400 for fixing the semiconductor light emitting device 300 in which a cap member 330 for hermetically sealing the semiconductor laser element is fixed to a disk-shaped base 321 holding a semiconductor laser element (not shown) is An opening 400a larger than the disk-shaped base 321 is formed. On the wall surface of the opening 400a, a stepped portion 400b that supports the base 321 on its upper surface is provided. Here, the opening diameter of the opening 400 a of the fixing jig 400 is set to be slightly larger than the diameter of the base 321 so that the base 321 of the semiconductor light emitting device 300 can be easily fitted.

JP 2009-135235 A JP 2008-028273 A

  However, the present inventors have found that the conventional semiconductor light emitting device has two problems in manufacturing.

  First, in order to increase the heat dissipation of the semiconductor light emitting device in order to achieve high light output, oxygen-free copper is used as a material having high thermal conductivity for the base constituting the package, for example, oxygen-free copper. The base made of copper cannot be resistance-welded with a cap member made of Kovar having a thermal expansion coefficient close to that of the transparent optical element constituting the light transmission window. This is because the heat conductivity and electrical conductivity of oxygen-free copper are sufficiently higher than Kovar, so the amount of current for resistance welding of Kovar does not generate sufficient heat at the welding site on the base side, This is because the generated heat diffuses to the periphery. On the other hand, when the amount of current during welding is increased in order to overheat the welded portion on the base side, the temperature on the cap member side excessively increases. For this reason, the adhesiveness between the cap member and the base cannot be sufficiently increased. As a result, the airtightness of the cap member is lowered, and the operating characteristics (optical characteristics) of the semiconductor light emitting element are lowered.

  On the other hand, when a material with high thermal conductivity such as copper is used so that the constituent material of the metal cover constituting the cap member matches the base, the thermal expansion coefficient of the light transmitting window, the soft glass, and the metal cover The difference becomes larger. For this reason, the adhesive strength of the soft glass which adheres the light transmission window and the metal cover during the production of the cap member is lowered, and the airtightness is lowered.

  In order to prevent a decrease in confidentiality, a method of brazing the cap member and the base with silver brazing or the like is also conceivable, but brazing exposes the semiconductor light emitting element to a high temperature near 1000 ° C., The semiconductor multilayer structure in the semiconductor light emitting element is altered, and the operating characteristics of the light emitting element are greatly deteriorated.

  From the above, when trying to improve the heat dissipation of the semiconductor light emitting device by using a material having high thermal conductivity for the base constituting the package, if the constituent material of the base is, for example, copper, inevitably its thermal expansion. A coefficient also becomes large and the airtightness with a cap member will fall. On the other hand, from the viewpoint of ensuring airtightness between the light transmission window and the metal cover, a material having a high thermal conductivity (a material having a large thermal expansion coefficient) cannot be used for the metal cover.

  Secondly, regarding the Joule heat generated during the operation from the semiconductor light emitting element in the semiconductor light emitting device, in the conventional configuration, as described above, it is attached to a fixing jig having an outer shape larger than the base of the package. Adhesiveness between the base and the fixing jig becomes insufficient. As a result, there is a problem that the temperature rise of the semiconductor light emitting element cannot be sufficiently suppressed.

  The present invention solves the above-described problems, and can efficiently dissipate Joule heat generated from the semiconductor light emitting element to the outside of the package while maintaining the airtightness of the metal cover for sealing the semiconductor light emitting element. The purpose is to do.

  In order to achieve the above-mentioned object, the present invention fixes a semiconductor light-emitting device on the base by making the thermal conductivity of the constituent material of the base constituting the package larger than the thermal conductivity of the metal cover. A welding stand is provided between the metal cover and the metal cover, which has a smaller difference in thermal conductivity than the base cover.

  Specifically, a semiconductor light emitting device according to the present invention includes a semiconductor light emitting element, a package that holds the semiconductor light emitting element, and a metal cover that is fixed to the package and seals the semiconductor light emitting element. And a welding base formed on the main surface of the base and capable of resistance-welding the metal cover, and the thermal conductivity of the first metal material constituting the base is a second that constitutes the metal cover. The difference in thermal conductivity between the metal cover and the base is smaller than the difference in thermal conductivity between the metal cover and the base.

  According to the semiconductor light emitting device of the present invention, the thermal conductivity of the first metal material constituting the base is larger than the thermal conductivity of the second metal material constituting the metal cover. The difference in thermal conductivity is smaller than the difference in thermal conductivity between the metal cover and the base. For this reason, since the difference of the heat conductivity and electrical conductivity of a metal cover and a welding stand can be made small, a metal cover and a welding stand can be joined easily by resistance welding. As a result, the adhesion between the base and the metal cover is improved, and deterioration of the characteristics of the semiconductor light emitting element can be prevented.

  In the semiconductor light emitting device of the present invention, the metal cover is provided with an opening at a position facing the semiconductor light emitting element, and a transparent optical element is fixed so as to cover the opening. The difference in thermal expansion coefficient is preferably smaller than the difference in thermal expansion coefficient between the transparent optical element and the base.

  In this way, the light from the semiconductor light emitting element can be efficiently extracted outside the package, and the airtightness of the semiconductor light emitting device can be prevented from being deteriorated. Can be prevented.

  In the semiconductor light emitting device of the present invention, at least one through hole is formed in the base, and the package has a lead fixed to the through hole with an insulating material interposed therebetween and electrically connected to the semiconductor light emitting element. You may do it.

  In this way, power can be easily and reliably supplied to the semiconductor light emitting device.

  In this case, the main surface of the base may be provided with a block portion for fixing the semiconductor light emitting element, and the welding base may be formed on the main surface of the base so as to surround the block portion and the through hole. .

  If it does in this way, electric power can be supplied to a semiconductor light-emitting device from the exterior through a lead, maintaining airtightness of a semiconductor light-emitting device.

  Further, in this case, a stepped portion may be provided on the peripheral edge portion of the main surface of the base, and the welding table may be formed on the stepped portion.

  In this case, an annular groove may be provided on the peripheral edge of the main surface of the base, and the welding table may be formed in the groove.

  If it does in this way, a contact area with the base of a welding stand will become large rather than a welding stand being formed in a level | step-difference part or a groove part, and adhesiveness with the base of a welding base will improve. Furthermore, the alignment at the time of forming the welding table is facilitated.

  In this case, the welding table may be formed in a region including the through hole, and the welding table and the insulating material of the through hole may be connected to each other.

  In this way, a part of the through hole for fixing the lead can be formed using a material different from that of the base. Therefore, if the constituent material of the welding base is close to the thermal expansion coefficient of the constituent material of the insulating material, the lead In addition, the airtightness of the fixed portion of the insulating material can be improved.

  In the semiconductor light emitting device of the present invention, the base may have a polygonal planar shape.

  If it does in this way, since the side surface of a base becomes planar, a contact area with the fixing jig which fixes a base can be enlarged easily. As a result, Joule heat generated from the semiconductor light emitting element can be radiated to the outside of the package through the side surface of the package base.

  In this case, the base may have a quadrangular planar shape.

  In this way, the design of the base becomes easy.

  In the semiconductor light emitting device of the present invention, the first metal material preferably contains copper as a main component.

  In this case, since a material having high thermal conductivity can be used as the constituent material of the base, an increase in temperature of the semiconductor light emitting element can be suppressed.

  In this case, the second metal material may contain iron.

  If it does in this way, since a package and a metal cover can be joined by resistance welding (electric welding), it can carry out airtight sealing easily.

  In the semiconductor light emitting device of the present invention, the semiconductor light emitting element may be a semiconductor laser element.

  In the semiconductor light emitting device of the present invention, the semiconductor light emitting element may be a super luminescent diode.

  In either case, since the directivity of light from the semiconductor light emitting element can be increased, light can be extracted to the outside with high efficiency from the light extraction opening.

  A first light source device according to the present invention includes the semiconductor light emitting device of the present invention and a plurality of fixing jigs for holding the semiconductor light emitting device by sandwiching the base from the side surface direction of the base. .

  According to the first light source device, in a light source device using one or more, particularly a plurality of semiconductor light emitting devices, Joule heat generated from the semiconductor light emitting elements can be efficiently radiated to the outside of the package. It is possible to prevent the deterioration of the characteristics.

  A second light source device according to the present invention includes a semiconductor light emitting device having a semiconductor light emitting element, a package holding the semiconductor light emitting element, a metal cover fixed to the package and sealing the semiconductor light emitting element, A plurality of fixing jigs for holding the semiconductor light emitting device are provided by sandwiching the base from the side surface direction of the base.

  According to the second light source device, in a light source device using one or more, particularly a plurality of semiconductor light emitting devices, Joule heat generated from the semiconductor light emitting element can be efficiently radiated to the outside of the package. It is possible to prevent the deterioration of the characteristics.

  In the first or second light source device, it is preferable that the plurality of fixing jigs do not contact each other.

  If it does in this way, in the light source device using a semiconductor light-emitting device, the adhesiveness of the side surface of the base in each semiconductor light-emitting device and a fixing jig can be improved. As a result, Joule heat generated from the semiconductor light emitting element can be efficiently radiated to the outside of the package.

  In the first or second light source device, the planar shape of the base constituting the semiconductor light emitting device may be a polygonal shape.

  If it does in this way, in the light source device using a semiconductor light-emitting device, the side of the base in a semiconductor light-emitting device will be constituted by a plurality of planes. Thereby, since the adhesiveness between the fixing jig and the side surface of the base is improved, Joule heat generated from the semiconductor light emitting element can be efficiently radiated to the outside of the package.

  In this case, the base constituting the semiconductor light emitting device may have a square shape in plan view.

  If it does in this way, in the light source device using a semiconductor light-emitting device, it will become easy to design the base which constitutes a semiconductor light-emitting device.

  According to the semiconductor light emitting device of the present invention, Joule heat generated from the semiconductor light emitting element can be efficiently radiated to the outside of the package while maintaining the airtightness of the metal cover for sealing the semiconductor light emitting element.

FIG. 1 is a schematic cross-sectional view showing a semiconductor light emitting device according to a first embodiment of the present invention. FIG. 2A is an exploded perspective view showing the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 2B is a perspective view showing the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view for explaining the operation of the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of one step showing the method for manufacturing the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of one step showing the method for manufacturing the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of one step showing the method for manufacturing a semiconductor light emitting device according to the first embodiment of the present invention. FIG. 7 is a diagram showing the thermal conductivity, thermal expansion coefficient, and the like of typical materials that can be used for the package of the semiconductor light emitting device according to the first embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing a semiconductor light emitting device according to a first modification of the first embodiment of the present invention. FIG. 9 is a graph showing the results of calculating the relationship between the thermal conductivity of the base and the thermal resistance of the semiconductor light emitting device in the semiconductor light emitting device according to the first modification of the first embodiment of the present invention. FIG. 10A is a graph showing current-light output characteristics in the semiconductor light emitting device according to the first modification of the first embodiment of the present invention. FIG. 10B is a graph showing the relationship between the light output and the power-light conversion efficiency in the semiconductor light emitting device according to the first modification of the first embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a semiconductor light emitting device according to a second modification of the first embodiment of the present invention. FIG. 12 is a schematic cross-sectional view showing a semiconductor light emitting device according to a third modification of the first embodiment of the present invention. FIG. 13 is a schematic cross-sectional view for explaining the operation of the semiconductor light emitting device according to the third modification of the first embodiment of the present invention. FIG. 14 is a schematic cross-sectional view showing a semiconductor light emitting device according to the second embodiment of the present invention. FIG. 15A is an exploded perspective view showing a semiconductor light emitting device according to the second embodiment of the present invention. FIG. 15B is a perspective view showing a semiconductor light emitting device according to the second embodiment of the present invention. FIG. 16A and FIG. 16B are schematic cross-sectional views in order of steps showing a method for fixing a semiconductor light emitting device according to the second embodiment of the present invention. FIG. 17 is a schematic cross-sectional view for explaining the operation of the semiconductor light emitting device according to the second embodiment of the present invention. FIG. 18A and FIG. 18B are schematic cross-sectional views in order of steps showing a method for fixing a semiconductor light emitting device according to a first modification of the second embodiment of the present invention. FIG. 19A and FIG. 19B are schematic cross-sectional views in order of steps showing a method for fixing a semiconductor light emitting device according to a second modification of the second embodiment of the present invention. FIG. 20A and FIG. 20B are schematic cross-sectional views in order of steps showing a method for fixing a semiconductor light emitting device according to a third modification of the second embodiment of the present invention. FIG. 21 is a schematic plan view showing a light source device according to the third embodiment of the present invention. FIG. 22A and FIG. 22B are schematic perspective views of one process showing a method for manufacturing a light source device according to the third embodiment of the present invention. FIG. 23 is a schematic cross-sectional view showing a conventional semiconductor light emitting device. FIG. 24 is a schematic perspective view of one process showing a conventional method for fixing a semiconductor light emitting device.

(First embodiment)
A semiconductor light emitting device according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the semiconductor light emitting device 1 according to the first embodiment includes a semiconductor light emitting element 3, a package 10 that holds the semiconductor light emitting element 3, and a semiconductor light emitting element that is, for example, a semiconductor laser element. 3 and a cap 20 that is fixed to the package 10 and seals the semiconductor light emitting element 3.

  The package 10 includes, for example, a base 11 made of oxygen-free copper (OFCu), a block portion 11b that is integrally formed on the main surface 11a and serves as a heat sink, and two through holes 11c that penetrate in the front and back directions. It has been. Leads 15 and 16 are fixed to the respective through holes 11c via insulating materials 18 and 19 made of, for example, hard glass. The leads 15 and 16 are electrically connected to the semiconductor light emitting element 3 via wires 30a and 30b, respectively. The lead 14 is resistance-welded (electrical welding) to the back surface of the base 11 and is electrically connected to the base 11.

  The peripheral portion of the base 11 on the main surface 11a, that is, the joint with the cap 20, has a smaller coefficient of thermal expansion than that of the base 11, for example, Kovar, Fe: Ni alloy (42 alloy) or iron (steel). The welding base 12 made of is hermetically bonded with an adhesive 13 such as silver solder. In the first embodiment, the planar shape of the welding table 12 is an annular shape, but may be, for example, a polygon or an ellipse as long as it can surround the block portion 11b.

  The cap 20 is, for example, a metal cover 21 made of Kovar, Fe: Ni alloy (42 alloy) or iron (steel) formed in a cylindrical shape, and light extraction is performed above the light emission surface of the semiconductor light emitting element 3. An opening 21b is formed. A transparent optical element 22 made of optical glass such as BK7 is fixed to the opening 21b by a fixing material 23 made of soft glass, for example. On the base 11 side of the metal cover 21, a flange portion 21 a that is open to the outside is provided so as to be easily fixed to the welding table 12.

  Further, as shown in FIG. 2, the semiconductor light emitting element 3 fixed to the block portion 11 b via the submount 6 has a stripe 3 a corresponding to the optical resonator formed in the semiconductor light emitting element 3 and the transparent optical element 22. It arrange | positions so that it may oppose.

  Next, the operation of the semiconductor light emitting device 1 according to the first embodiment will be described with reference to FIG.

  When the semiconductor light emitting device 1 is incorporated into a product, the base 11 is fixed so as to be in close contact with a fixing jig 50 made of a material having high thermal conductivity such as an aluminum alloy, and is further fixed from above by a pressing jig 51. It is fixed so as to be sandwiched. At this time, power is supplied to the semiconductor light emitting element 3 through leads 15 and 16 from an external power source (not shown). The electric power applied to the semiconductor light emitting element 3 is converted into light having a predetermined wavelength and emitted. The light emitted from the semiconductor light emitting element 3 has a predetermined divergence angle in a direction from the semiconductor light emitting element 3 toward the transparent optical element 22 provided in the opening 21b (main line 70a = normal line of the main surface 11a). The emitted light 70 is transmitted through the transparent optical element 22 and emitted to the outside of the semiconductor light emitting device 1.

  On the other hand, in the semiconductor light emitting element 3, when the applied power is converted into light, a part of the power is not converted into light but becomes Joule heat. Joule heat generated from the semiconductor light emitting element 3 is conducted through the submount 6, the block portion 11 b and the base 11 and is released to the outside of the package 10. Since the base 11 is in close contact with the fixed jig 50 by the holding jig 51, the base 11 can efficiently radiate heat through the heat dissipation path 60. Part of the Joule heat contributes to a temperature increase in the semiconductor light emitting element 3 and the vicinity thereof, and increases the temperature of the semiconductor light emitting element 3.

  Hereinafter, a method of manufacturing the semiconductor light emitting device configured as described above will be described with reference to FIGS.

  FIG. 4 shows a cross-sectional configuration of the package 10 constituting the semiconductor light emitting device 1 according to the first embodiment.

  First, a mold 10 that can form the base 11 and the block portion 11b is made of oxygen-free copper (OFCu), and the base 11 and the block portion 11b are formed integrally by, for example, press working. To do. The base 11 and the block portion 11b are not necessarily formed integrally. However, if the same constituent material, for example, oxygen-free copper having a high thermal conductivity is used for the base 11 and the block portion 11b, Integral molding is preferred. Subsequently, the annular welding table 12 is bonded to the main surface 11a of the base 11 by an adhesive 13 made of, for example, silver solder so as to surround the block portion 11b. In the bonding step of the welding table 12, the lead 14 is bonded to the back surface of the base 11 by a high temperature treatment using an adhesive 13 made of, for example, silver solder. Subsequently, using a predetermined jig, the leads 15 and 16 are inserted into the respective through holes 11c together with the cylindrical glass to be the insulating materials 18 and 19, and then the insulating materials 18 and 19 made of glass are further inserted into the respective through holes. By filling the hole 11c and heating it to the glass softening temperature or higher, the leads 15 and 16 are fixed to the through holes 11c via the insulating materials 18 and 19, respectively. In addition, it is preferable to change according to process temperature about the order of adhesion | attachment of said lead | read | reed 14,15 and 16, and adhesion | attachment of the welding stand 12. FIG. Moreover, it is preferable to coat the surface of the base 11 and the block part 11b by Ni / Au plating, for example, at the end or in the middle of the above process.

  Next, as shown in FIG. 5, the semiconductor light emitting element 3 is fixed on the inner side surface of the block portion 11 b in the base 11 via a submount 6 made of, for example, AlN ceramic or SiC ceramic. Thereafter, the semiconductor light emitting element 3 and the leads 15 and 16 are electrically connected by wires 30a and 30b, respectively. On the other hand, the cap 20 forms a flange portion 21a and an opening portion 21b on a cylindrical metal cover 21 made of a material having a thermal expansion coefficient close to that of glass, such as Kovar, by pressing. At this time, a projection 21c for welding is formed on the lower surface of the flange portion 21a. Subsequently, for example, the transparent optical element 22 made of an optical glass having an antireflection film having a low reflectance with respect to the wavelength of light emitted from the semiconductor light emitting element 3 on the surface thereof is used as the fixing material 23 made of, for example, soft glass. Due to this, it is fixed inside the opening 21b.

  In the above description, the semiconductor light emitting device 3 is fixed to the block portion 11b with the submount 6 interposed therebetween, but the semiconductor light emitting device 3 is directly fixed to the block portion 11b without the submount 6 interposed. Also good.

  Next, a method for joining the package 10 and the cap 20 according to the first embodiment will be described with reference to FIG.

  First, the base 11 of the package 10 to which the semiconductor light emitting element 3 is fixed is fixed at a predetermined position using the fixing base 31a. Subsequently, the flange portion 21a of the metal cover 21 constituting the cap 20 is fixed using the pressing portion 31b. Subsequently, using the fixing base 31a and the pressing portion 31b, the protrusion 21c formed on the lower surface of the flange portion 21a is disposed on the welding base 12 bonded onto the base 11. Subsequently, the pressing portion 31b is pressed against the upper surface of the flange portion 21a, and a predetermined current is passed through the pressing portion 31b → the flange portion 21a → the welding table 12 → the base 11 → the fixing table 31a, thereby lowering the lower surface of the flange portion 21a. The protrusion 21c is heated and melted, and the metal cover 21 and the welding base 12 are welded.

  At this time, since the metal cover 21 and the welding table 12 are made of the same material system such as 42 alloy, the metal cover 21 and the welding table 12 can be easily separated after the protrusion 21c of the metal cover 21 is melted by heating. Join. As shown in FIG. 3, Joule heat generated from the semiconductor light emitting element 3 is conducted through the base 11 having a high thermal conductivity and is efficiently radiated to the outside of the fixing jig 50 and the like. For this reason, since the temperature rise of the semiconductor light emitting element 3 can be suppressed, the deterioration of the operating characteristics of the semiconductor light emitting element 3 can be prevented.

The above heat conduction will be described in more detail using a list of various material characteristics shown in FIG. FIG. 7 is a table showing the thermal conductivity, thermal expansion coefficient, and the like of typical materials that can be used for the package of the semiconductor light emitting device. Currently, high thermal conductivity materials constituting packages of semiconductor light emitting devices are copper-based materials such as pure copper such as oxygen-free copper and copper alloys such as copper tungsten, steel (SPC, Cold Roller Steel), Fe: Ni alloy. Iron / stainless steel materials such as (42 alloy) and Kovar (Fe—Ni—Co alloy), or aluminum materials such as aluminum alloy (A5052) and pure aluminum, etc. are the mainstream. Moreover, BK7 is mentioned as a typical thing in the optical glass which comprises a transparent optical element. As can be seen from FIG. 7, the thermal expansion coefficient of the optical glass constituting the transparent optical element provided on the cap is as low as 7.5 × 10 ⁻⁶ / K, so that the metal cover is in close contact with the transparent optical element 22 according to the present embodiment. It is necessary to set the thermal expansion coefficient of 21 and the fixing material 23 low. The constituent material of the metal cover 21 is required to satisfy this condition, to be excellent in press workability, and to be low in cost. Therefore, an iron-based material such as Kovar is used as the constituent material of the metal cover 21. On the other hand, the fixing material 23 is made of soft glass in order to increase the adhesion between the transparent optical element 22 and the metal cover 21. Therefore, in order to facilitate resistance welding with the metal cover 21, the thermal expansion of iron and nickel, such as Kovar, Fe: Ni alloy (42 alloy), steel (SPC), or nickel, is performed on the welding table 12. A material having a relatively small coefficient and being close to the material constituting the metal cover 21 is used.

  On the other hand, as a material which comprises the base 11 and the block part 11b, gold | metal | money, silver, copper, a copper alloy, aluminum, or aluminum alloy etc. which are materials with high heat conductivity are preferable. More specifically, copper, aluminum, an aluminum alloy, or the like that is relatively low cost and excellent in press properties is preferable.

(First modification of the first embodiment)
Hereinafter, a first modification of the first embodiment will be described with reference to FIGS.

  As shown in FIG. 8, the semiconductor light emitting device 1A according to the first modification has a step portion 11d having a lower outer side (side surface side) formed at the peripheral edge of the main surface of the base 11A constituting the package 10A. ing. The welding table 12 is hermetically bonded with an adhesive 13 made of silver brazing or the like on the bottom surface of the step portion 11d formed so as to surround the block portion 11b and the through hole 11c so as to contact the wall surface.

  If it does in this way, since the contact area with the welding stand 12 of 11 A of bases will increase, the adhesiveness of the welding stand 12 and 11 A of bases can be improved. Furthermore, in the bonding process of the welding table 12 shown in FIG. 4, the alignment when forming the welding table 12 on the main surface of the base 11A becomes easy.

  Next, the effect of the semiconductor light emitting device 1A according to the first modification configured as described above will be described based on experimental data.

  FIG. 9 shows a result obtained by calculating a change in thermal resistance of the semiconductor light emitting device 1A when the thermal conductivity of the base 11A of the semiconductor light emitting device 1A according to the first modification is changed. Here, the planar shape of the base 11A constituting the package 10A is circular, and the outer diameter D1 is 5.6 mm. As shown in FIG. 8, the base 11 </ b> A is in contact with the fixing jig 50 from the outer peripheral portion of the back surface opposite to the main surface 11 a to the inner diameter D <b> 2 of 4.5 mm. The fixing jig 50 can be regarded as an infinite heat radiation surface.

  Oxygen-free copper is used for the block part 11b, and the thermal conductivity is 390 W / mK. As a result, as the thermal conductivity of the base 11A increases, the thermal resistance of the semiconductor light emitting device 1A decreases significantly. In particular, it can be seen that when the thermal conductivity of the base 11A is 200 W / mK or more, the thermal resistance of the semiconductor light emitting device 1A is saturated and becomes constant at about 12 K / W. Structure A and structure B are measurement data for a semiconductor light emitting device manufactured by the present inventors. In the structure A, the base 11A and the block portion 11b are integrally molded, and oxygen-free copper (OFCu) is used as a constituent material thereof. On the other hand, the structure B is for comparison, and steel (iron, SPC) is used for the base 11A, oxygen-free copper is used for the constituent material of the block portion 11b, and both are joined by brazing.

  As can be seen from FIG. 9, these measurement results agree well with the calculation results. That is, it can be seen that the thermal resistance in the semiconductor light emitting device 1A can be greatly reduced by using a material having high thermal conductivity for the base 11A.

  Furthermore, FIG. 10A and FIG. 10B compare the current-light output characteristics and the relationship between light output-power light conversion efficiency in each of the semiconductor light emitting devices according to the structures A and B, respectively. Show. First, in the current-light output characteristics shown in FIG. 10A, the maximum light output of the structure A is improved from 2.0 W to 2.5 W as compared with the structure B.

  Moreover, in the light output-power light conversion efficiency shown in FIG.10 (b), it turns out that the structure A is improving about 10% compared with the structure B. FIG. The improvement in these characteristics is because the thermal resistance in the semiconductor light emitting device 1A is reduced by changing the material of the base 11A constituting the package 10A to a material having a high thermal conductivity.

  As described above, the structure according to the present embodiment can greatly improve the characteristics of the semiconductor light emitting device.

(Second modification of the first embodiment)
Hereinafter, a semiconductor light emitting device according to a second modification of the first embodiment will be described with reference to FIG.

  The semiconductor light emitting device 1B according to the second modification has a groove portion 11e formed so as to surround the block portion 11b and the through hole 11c at the peripheral portion of the main surface of the base 11B constituting the package 10B. . The welding table 12 is hermetically bonded with an adhesive 13 made of silver brazing or the like so as to be embedded in the groove 11e.

  If it does in this way, since the contact area with the welding stand 12 of the base 11B will increase with the bottom face and both wall surfaces of the groove part 11e, the adhesiveness of the welding stand 12 and the base 11B will improve further. Furthermore, in the bonding step of the welding table 12 shown in FIG. 4, the welding table 12 can be formed on the main surface of the base 11 </ b> B in a self-aligning manner.

(Third Modification of First Embodiment)
Hereinafter, a semiconductor light emitting device according to a third modification of the first embodiment will be described with reference to FIGS.

  As shown in FIG. 12, the semiconductor light emitting device 1C according to the third modification has a step portion 11d1 whose outer side (side surface side) is formed low on the peripheral edge of the main surface of the base 11C constituting the package 10C. ing. Here, in the third modified example, unlike the first modified example, the step portion 11d1 is formed up to a region including the formation region of the through hole 11c, that is, a region surrounding the vicinity of the side surface of the block portion 11b. Yes. Therefore, each through-hole 11c is formed in the area | region of the bottom face of level | step-difference part 11d1.

  A welding base 12 made of, for example, Fe: Ni alloy (42 alloy) having a smaller thermal expansion coefficient than that of the base 11C is bonded to the main surface 11a of the base 11C by an adhesive 13 made of, for example, silver brazing. Yes. Here, the welding table 12 has an annular shape, and an opening for penetrating the leads 15 and 16 is formed in a part of the welding table 12 in a region corresponding to the through hole 11c of the base 11C. The welding table 12 is hermetically bonded to the bottom and side surfaces of the step portion 11d1. Further, the leads 15 and 16 are fixed to the respective through holes 11c and the respective openings of the welding table 12 via an insulating material 18 made of, for example, hard glass.

  Next, the operation of the semiconductor light emitting device 1C according to the third modification will be described with reference to FIG.

  As shown in FIG. 13, the semiconductor light emitting device 1 </ b> C is fixed with the peripheral portion of the base 11 </ b> C sandwiched from above and below by a fixing jig 50 and a holding jig 51. The emitted light 70 emitted from the semiconductor light emitting element 3 in the cap 20 has a main line 70a (normal line of the main surface 11a) in the direction toward the transparent optical element 22 provided in the light extraction opening 21b as a central axis. Radiated, transmitted through the transparent optical element 22, and emitted to the outside of the package 10C. On the other hand, Joule heat generated from the semiconductor light emitting element 3 is conducted through the submount 6, the block portion 11b, and the base 11C, and is released to the outside of the package 10C.

  At this time, the upper part of the through-hole 11c in each lead | read | reed 15 and 16 is covered with the welding stand 12 which consists of 42 alloy with a small thermal expansion coefficient. Therefore, even if the temperature of the semiconductor light emitting device 1C rises, the difference in thermal expansion coefficient between the leads 15, 16 and the insulating materials 18, 19 and the welding base 12 is small, so that the airtightness in the cap 20 is improved. can do. As a result, the deterioration of the operating characteristics of the semiconductor light emitting element 3 can be sufficiently suppressed.

(Second Embodiment)
Hereinafter, a semiconductor light emitting device according to a second embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 14, in the semiconductor light emitting device 1D according to the second embodiment, the thickness of the base 11D constituting the package 10D is set to be equal to the width of the base 11D. Further, as shown in FIGS. 15A and 15B, the planar shape of the base 11D is a polygonal shape, for example, a rectangular shape. As a result, the area of the side surface of the base 11D is increased and the four side surfaces have a planar shape, so that the contact area with the fixing jig and the like is also increased. As a result, Joule heat from the semiconductor light emitting element 3 can be efficiently exhausted.

  The semiconductor light emitting device 1D according to the second embodiment has the same configuration as that of the third modification of the first embodiment, in which the welding base 12 is formed in the step portion 11d1 having a large bottom area. The configuration of the welding stand 12 is not limited, and may be the same configuration as that of the first embodiment, the first modified example, or the second modified example.

  A detailed configuration of the semiconductor light emitting device 1D according to the second embodiment will be described.

  As shown in FIGS. 14 and 15, the semiconductor light emitting element 3A is, for example, a semiconductor laser array having a plurality of stripes. For example, a high output nitride having an emission wavelength in the range of 380 nm to 550 nm and an optical output exceeding 1 W. Semiconductor laser device. The semiconductor light emitting element 3A is fixed to the block portion 11b of the base 11D constituting the package 10D via the submount 6.

  FIGS. 16A and 16B show an example of a method for fixing the semiconductor light emitting device 1D according to the second embodiment to a fixing jig.

  As shown in FIG. 16 (a), the first fixing jig 150 and the second fixing jig 160 that are paired with each other have recesses that fit into the two side surfaces of the package 10D of the semiconductor light emitting device 1D. ing. Further, the first fixing jig 150 is provided with screw holes 155a and 155b on the side surface on the concave side so that the fixing jigs 150 and 160 can be screwed to each other. Are provided with through holes 165a and 165b penetrating the side surfaces of the first fixing jig 150 facing the screw holes 155a and 155b. Further, the first fixing jig 150 and the second fixing jig 160 have mounting holes 150a and 150b and 160a and 160b so that the main surface penetrates in the front and back direction and can be attached to other members. Each is provided.

  As shown in FIG. 16B, the package 10D constituting the semiconductor light emitting device 1D is held so as to be sandwiched between the first fixing jig 150 and the second fixing jig 160, and is fixed by screws 180a and 180b. The Here, it is preferable that the opposing surfaces of the first fixing jig 150 and the second fixing jig 160 are not in contact with each other, that is, a gap is formed. If it does in this way, the planar side surface of base 11D which comprises package 10D can be made to contact reliably the inner surface of the recessed part of each fixing jig 150,160.

  Next, the operation of the semiconductor light emitting device 1D according to the second embodiment will be described with reference to FIG.

  As shown in FIG. 17, the semiconductor light emitting device 1 </ b> D is fixed with the side surface of the base 11 </ b> D sandwiched between the first fixing jig 150 and the second fixing jig 160.

  In this state, the semiconductor light emitting element 3A converts the power supplied from the leads 14, 15 and 16 and the wires 30a, 30b and 30c and other leads and wires (not shown) into light. The converted outgoing light 70 is transmitted through the transparent optical element 22 with the main line 70a (normal line of the main surface 11a) as the central axis, and is output to the outside. On the other hand, Joule heat generated from the semiconductor light emitting element 3A can be radiated to the fixing jigs 150 and 160 from a plurality of relatively wide planar side surfaces of the base 11D.

  As described above, according to the second embodiment, since Joule heat from the semiconductor light emitting element can be efficiently radiated to the outside, it is possible to prevent deterioration in operating characteristics due to a temperature rise of the semiconductor light emitting element 3A.

(First Modification of Second Embodiment)
Hereinafter, a semiconductor light emitting device according to a first modification of the second embodiment will be described with reference to FIG.

  As shown in FIGS. 18A and 18B, the planar shape of the base 11E of the package according to the first modification is triangular. The first fixing jig 150 is formed with a recess that fits with a planar portion of one side surface of the base 11E. In addition, the second fixing jig 160 is formed with a recess that fits with two adjacent side surfaces of the base 11E.

  Therefore, by sandwiching the three side surfaces of the base 11E from opposite sides, the base 11E of the package and the fixing jigs 150 and 160 can be accurately fixed. In addition, since the side surfaces of the base 11E and the inner surfaces of the recesses provided in the fixing jigs 150 and 160 are in contact with each other, the heat generated from the semiconductor light emitting device 1D can be efficiently radiated to the outside.

(Second modification of the second embodiment)
Hereinafter, a semiconductor light emitting device according to a second modification of the second embodiment will be described with reference to FIG.

  As shown in FIGS. 19A and 19B, the planar shape of the base 11F of the package according to the second modification is a pentagonal shape. The first fixing jig 150 is formed with a recess that fits with a planar portion of one side surface of the base 11F. In addition, the second fixing jig 160 is formed with a recess that fits with two adjacent side surfaces of the base 11F.

  Accordingly, by sandwiching the three side surfaces of the base 11F from opposite sides, the base 11F of the package and the fixing jigs 150 and 160 can be accurately fixed. In addition, since the side surfaces of the base 11F and the inner surfaces of the recesses provided in the fixing jigs 150 and 160 are in contact with each other, the heat generated from the semiconductor light emitting device 1D can be efficiently radiated to the outside.

(Third Modification of Second Embodiment)
Hereinafter, a semiconductor light emitting device according to a third modification of the second embodiment will be described with reference to FIG.

  As shown in FIGS. 20A and 20B, the planar shape of the base 11G of the package according to the third modification is a hexagonal shape. The first fixing jig 150 and the second process jig 160 are each formed with a recess that fits with a planar portion of two adjacent side surfaces of the base 11G.

  Therefore, the base 11G of the package and the fixing jigs 150 and 160 can be accurately fixed by sandwiching the four opposing side surfaces of the base 11G from the opposing sides. In addition, since the side surfaces of the base 11G and the inner surfaces of the recesses provided in the fixing jigs 150 and 160 are in contact with each other, the heat generated from the semiconductor light emitting device 1D can be efficiently radiated to the outside.

  In the second embodiment and the modification thereof, the semiconductor light emitting element 3A is a high output nitride semiconductor laser array having an emission wavelength of 380 nm to 550 nm and an optical output exceeding 1 W, for example. Not limited. For example, a single-wavelength semiconductor laser element may be used as the semiconductor light emitting element, and a nitride semiconductor superluminescent diode with low speckle noise suitable for a backlight of an image display device may be used. Good. Furthermore, for example, a semiconductor laser element or a super luminescent diode made of an (Al, In, Ga, P, As) material having a wavelength of 550 nm to 660 nm may be used.

  Moreover, although the semiconductor light-emitting device 1D which concerns on 2nd Embodiment provides the welding stand 12 in the junction part of base 11D and the metal cover 21, in this embodiment, the conventional welding stand 12 is not provided. Even if it is a semiconductor light-emitting device, if the fixing jig 150,160 which concerns on this embodiment which makes the base thickness thick, makes the planar shape polygonal shape, and also adhere | attaches and fixes to the side surface will be welded It becomes possible to improve the heat dissipation of the semiconductor light emitting device in which the base 12 is not provided.

(Third embodiment)
Hereinafter, a light source device according to a third embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 21, the light source device 201 according to the third embodiment includes, for example, six semiconductor light emitting devices 1D according to the second embodiment, and a first fixing jig that fixes and holds them. 250, a second fixing jig 260, and a third fixing jig 270.

  The first fixing jig 250 is provided with three concave portions that are respectively fitted to two adjacent side surfaces of the package 10D constituting the semiconductor light emitting device 1D on one side surface thereof. In addition, the second fixing jig 260 is provided with six concave portions that are respectively fitted to two adjacent side surfaces of each base 10D on two side surfaces facing each other. Further, the third fixing jig 270 is also provided with three concave portions that are respectively fitted to two adjacent side surfaces of the base 10 </ b> D on the side surface facing the second fixing jig 260.

  The fixing jigs 250, 260, and 270 are provided with mounting holes 250a, 250b, 260a, 260b, 270a, and 270b that penetrate the respective main surfaces in the front and back directions and can be attached to other members. ing.

  As shown in FIG. 22, the six semiconductor light emitting devices 1D are sandwiched by the fixing jigs 250, 260, and 270 from opposite diagonal directions, and are fixed by the screws 280a to 280d and 281a to 281d, respectively. .

  As described above, according to the third embodiment, the planar shape of the base 11D constituting the semiconductor light emitting device 1D is configured as a polygonal shape with a plurality of planes, so that the concave portions of the fixing jigs 250, 260, and 270 are formed. Since it is in surface contact with the inner surface, the heat generated by each semiconductor light emitting device 1D can be efficiently radiated to each fixing jig 250, 260, and 270.

  In addition, as shown in FIG. 21, it is preferable that the mutually opposing surfaces of the fixing jigs 250, 260, and 270 do not contact each other, that is, a gap is formed. If it does in this way, the planar side surface of package 10D can be reliably made to contact the inner surface of the recessed part of each fixing jig 250,260,270.

  In the third embodiment, the semiconductor light emitting device 1D including the semiconductor light emitting element 3A having the laser array structure is used for the light source device. However, the present invention is not limited to this. That is, a single-wavelength semiconductor laser element may be used as the semiconductor light-emitting element, and a nitride semiconductor superluminescent diode with low speckle noise that is suitable for a backlight of an image display device may be used. Good.

  In the third embodiment, the same semiconductor light emitting device 1D is used for the plurality of semiconductor light emitting devices used in the light source device. However, the present invention is not limited to this. For example, as a semiconductor light emitting element mounted on a semiconductor light emitting device used in a light source device, a nitride semiconductor light emitting element having an emission wavelength of 380 nm to 490 nm, a nitride semiconductor light emitting element having an emission wavelength of 490 nm to 550 nm, and an emission wavelength of A total of six 550 nm to 640 nm (Al, In, Ga, P, As) -based semiconductor light emitting elements may be arranged to emit white light as emitted light from the light source device. .

  Further, in the third embodiment, the semiconductor light emitting device 1D according to the second embodiment is used as the semiconductor light emitting device, but the configuration of the welding table 12 is the same as that of the first embodiment, the first modified example, or A configuration equivalent to the second modification may be used.

  Furthermore, the semiconductor light emitting device 1D according to the third embodiment has the welding table 12 provided at the joint between the base 11D and the metal cover 21, but in this embodiment, the conventional welding table 12 is not provided. Even in the case of a semiconductor light emitting device, if the fixing jigs 250, 260, and 270 according to the present embodiment are used in which the thickness of the base is increased, the planar shape is a polygonal shape, and the surface is fixed in close contact with the side surface. Further, it is possible to improve the heat dissipation of the semiconductor light emitting device that does not include the welding table 12.

  The semiconductor light emitting device and the light source device according to the present invention can efficiently dissipate Joule heat generated from the semiconductor light emitting element to the outside of the package while maintaining the airtightness of the metal cover that seals the semiconductor light emitting element. This is useful for a semiconductor light emitting device and a light source device having a high intensity of emitted light used for a display such as a projector.

DESCRIPTION OF SYMBOLS 1 Semiconductor light-emitting device 1A Semiconductor light-emitting device 1B Semiconductor light-emitting device 1C Semiconductor light-emitting device 1D Semiconductor light-emitting device 3 Semiconductor light-emitting device 3a Stripe 3A Semiconductor light-emitting device 6 Submount 10 Package 10A Package 10B Package 10C Package 10D Package 11 Base 11A Base 11B Base 11C Base 11D Base 11E Base 11F Base 11G Base 11a Main surface 11b Block 11c Through-hole 11d Step 11d1 Step 11e Groove 12 Welding base 13 Adhesive 14 Lead 15 Lead 16 Lead 18 Insulating material 19 Insulating material 20 Cap 21 Metal cover 21a Flange portion 21b Opening portion 21c Projection portion 22 Transparent optical element 23 Adhering material 25 Welding portion 30a Wire 30b Wire 30c Wire 31a Fixing base 31b Holding portion 50 Fixing jig 51 Pressing The first fixing jig 150a The mounting hole 150b The mounting hole 155a The screw hole 155b The screw hole 160 The second fixing jig 160a The mounting hole 160b The mounting hole 165a The through hole 165b The through hole 180a The screw 180b The screw 201 The light source Device 250 First fixing jig 250a Mounting hole 250b Mounting hole 260 Second fixing jig 260a Mounting hole 260b Mounting hole 270 Third fixing jig 270a Mounting hole 270b Mounting hole 280a Screw 280b Screw 280c Screw 280d Screw 281a Screw 281b screw 281c screw 281d screw

Claims (18)

A semiconductor light emitting device;
A package for holding the semiconductor light emitting element;
A metal cover fixed to the package and sealing the semiconductor light emitting element;
The package includes a base and a welding base formed on the main surface of the base and capable of resistance welding the metal cover,
The thermal conductivity of the first metal material constituting the base is greater than the thermal conductivity of the second metal material constituting the metal cover,
The semiconductor light emitting device characterized in that a difference in thermal conductivity between the metal cover and the welding table is smaller than a difference in thermal conductivity between the metal cover and the base. The metal cover is provided with an opening at a position facing the semiconductor light emitting element, and a transparent optical element is fixed so as to cover the opening,
2. The semiconductor light emitting device according to claim 1, wherein a difference in thermal expansion coefficient between the transparent optical element and the metal cover is smaller than a difference in thermal expansion coefficient between the transparent optical element and the base. At least one through hole is formed in the base,
3. The semiconductor light emitting device according to claim 1, wherein the package includes a lead fixed to the through hole with an insulating material interposed therebetween and electrically connected to the semiconductor light emitting element. 4. . The main surface of the base is provided with a block portion for fixing the semiconductor light emitting element,
The semiconductor light-emitting device according to claim 3, wherein the welding table is formed on a main surface of the base so as to surround the block portion and the through hole. A step portion is provided on the peripheral edge of the main surface of the base,
The semiconductor light emitting device according to claim 4, wherein the welding table is formed in the stepped portion. An annular groove is provided on the peripheral edge of the main surface of the base,
The semiconductor light emitting device according to claim 4, wherein the welding table is formed in the groove. The welding table is formed in a region including the through hole,
The semiconductor light-emitting device according to claim 3, wherein the welding table and the insulating material of the through hole are connected to each other.   The semiconductor light-emitting device according to claim 1, wherein the base has a polygonal planar shape.   The semiconductor light emitting device according to claim 8, wherein the base has a quadrangular planar shape.   The semiconductor light emitting device according to claim 1, wherein the first metal material contains copper as a main component.   The semiconductor light emitting device according to claim 10, wherein the second metal material includes iron.   The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting element is a semiconductor laser element.   The semiconductor light-emitting device according to claim 1, wherein the semiconductor light-emitting element is a superluminescent diode. A semiconductor light emitting device according to any one of claims 1 to 13,
A light source device comprising: a plurality of fixing jigs for holding the semiconductor light emitting device by sandwiching the base from the side surfaces of the base. A semiconductor light emitting device comprising: a semiconductor light emitting element; a package holding the semiconductor light emitting element; and a metal cover fixed to the package and sealing the semiconductor light emitting element;
A light source device comprising: a plurality of fixing jigs for holding the semiconductor light emitting device by sandwiching the base from the side surfaces of the base.   The light source device according to claim 14 or 15, wherein the plurality of fixing jigs do not contact each other.   The light source device according to any one of claims 14 to 16, wherein the base of the semiconductor light emitting device has a polygonal planar shape.   The light source device according to claim 17, wherein the base constituting the semiconductor light emitting device has a quadrangular planar shape.

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