Abstract:
The present invention discloses a semiconductor laser device having: a lead frame; a resin molding provided for sealing a part of said lead frame and including a main body and a flange portion having opposite end faces, said resin molding being formed into such a shape that said flange portion protrudes outwardly from a periphery of said main body; a laser chip having an optical axis and mounted on a surface of said lead frame for emitting laser light; and a heat-radiating fin provided on said lead frame for cooling said laser chip, said heat-radiating fin being disposed in an exposed state on the side of at least one of said two end faces of said flange portion.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a resin molding type of semiconductor laser device, and to a method for manufacturing the same. 
     2. Description of the Related Art 
     Semiconductor laser devices have been utilized in the past for optical disk players, laser printers, and other such optical response devices. Semiconductor laser devices come in can types and resin molding types, for example, with a laser chip mounted to a frame. 
     As shown in FIG. 13, a can type of semiconductor laser device  1  comprises a laser chip  2  that emits laser light, and this laser chip  2  is mounted on the side of a rectangular heat-radiating body  3  that is parallel to the optical axis. This heat-radiating body  3  is erected on the top of a disk-shaped stem  4 , and a cylindrical cap  5  is mounted around its periphery. A glass window is provided to the top of the cap  5 , and the laser chip  2  faces the glass window  6  from the inside of the cap  5 . Because the outside diameter of the stem  4  is larger than that of the cap  5 , the outer periphery of the stem  4  that sticks out further than this cap  5  becomes a flange  7 . 
     With the can type of semiconductor laser device  1  described above, when the laser chip  2  inside the cap  5  emits laser light, this laser light is emitted through the glass window  6 . The laser chip  2  generates heat at this time, but because the inside of the cap  5  is hollow, this heat is radiated by the stem  4 , which acts as a heat-radiating fin. 
     With the can type of semiconductor laser device  1  described above, since in structural terms the laser chip  2  is fixed with good precision to the stem  4 , as shown in FIG. 14, laser light can generally be emitted accurately with respect to a device housing  8  if the shape of the flange  7  is utilized for mounting in a stepped hole  9  of the device housing  8 . 
     However, the can type of semiconductor laser device  1  comprises numerous parts and has a complicated construction. In view of this, a semiconductor laser device in which the laser chip is sealed with a resin molding has been developed in an effort to simplify the construction and improve productivity. 
     For instance, as shown in FIG. 15, the resin molding type of semiconductor laser device  11  disclosed in Japanese Laid-Open Patent Application No. Hei7-170019 has the laser chip  2  mounted to a lead frame  13  via a sub-mount layer  12 , and the laser chip  2  is sealed along with the upper portion of this lead frame  13  by a transparent resin molding  14 . Furthermore, this resin molding  14  is formed in the same shape as in the above-mentioned can type, so interchangeability is ensured so that mounting to the device housing  8  can be performed just as with a can type. 
     As shown in FIG. 16, the resin molding type of semiconductor laser device  21  disclosed in Japanese Laid-Open Utility Model Application No. Hei2-54263 has a convex component  23  that serves as a heat-radiating fin formed on both sides of a lead frame  22 , and these convex components  23  protrude to the outside of a resin molding  24 , which enhances the heat radiation of the laser chip  2  sealed by the resin. The resin molding type of semiconductor laser devices  11  and  21  discussed above offer a simple construction and good productivity. 
     However, although interchangeability is good with the semiconductor laser device  11  in Japanese Laid-Open Patent Application No. Hei7-170019 because the resin molding  14  is formed in the same shape as that of a can type, the thermal radiation of the laser chip  2  sealed by this resin molding  14  is difficult. Furthermore, with the semiconductor laser device  11 , the lead frame  13  to which the laser chip  2  is fixed is inserted into the resin molding  14 , but it is difficult to position the lead frame  13  accurately with respect to this resin molding  14 . Accordingly, the positioning precision of the laser chip  2  with respect to the resin molding  14  is low, and it is difficult to direct the laser light at the proper location when the semiconductor laser device is mounted in the device housing  8  at the resin molding  14  portion. 
     In contrast, since convex components  23  that serve as heat-radiating fins are formed on the lead frame  22  with the semiconductor laser device  21  discussed in Japanese Laid-Open Utility Model Application No. Hei2-54363, the heat generated by the laser chip  2  can be eliminated very well, and the lead frame  22  can be inserted at the proper location with respect to the resin molding  24  by means of these convex components  23 . However, since the convex components  23  of the lead frame  22  stick out on both sides of the resin molding  24 , it is difficult for the shape thereof to be formed the same as that of a can type and thereby ensure interchangeability. 
     Also, with the resin molding type of semiconductor laser devices  11  and  21  discussed above, the laser chip  2  is also sealed with the resin moldings  14  and  24  along with the lead frames  13  and  22 , but this is undesirable since the laser chip  2  is subjected to high temperature and pressure during the molding of the resin moldings  14  and  24  with this configuration, and there is the possibility of breakage. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a resin molding type of semiconductor laser device with which interchangeability with a conventional can type is ensured, while the thermal radiation of the laser chip is also good, the positioning precision of the laser light is high, and there is no danger of breakage in the laser chip during molding. 
     In order to achieve the above-mentioned object, according to a first aspect of the present invention, there is provided a semiconductor laser device in which a laser chip that emits laser light is mounted on the surface of a lead frame that is parallel to the optical axis, and part of the lead frame is sealed with a resin molding having a main body, wherein the semiconductor laser device is such that the resin molding is formed in a shape such that a flange protrudes from around the outside at the end of this main body, a heat-radiating fin for cooling the laser chip is provided to the lead frame, and the heat-radiating fin is exposed on the side of at least one of the two end faces of the flange. 
     Therefore, according to the above-mentioned first aspect, heat generated by the laser chip can be eliminated favorably since a heat-radiating fin for cooling the laser chip is provided to the lead frame, and this heat-radiating fin is exposed on the side of at least one of the two end faces of the flange of the resin molding. With this configuration, the resin molding is shaped roughly the same as in a conventional can type, so interchangeability with a conventional can type is ensured. Furthermore, since the lead frame can be positioned in the cavity of the metal mold by the heat-radiating fin when the resin molding is molded, there is an improvement in the precision of the relative positions of the optical axis of the laser chip and the shape of the resin molding. 
     In the above-mentioned first aspect, the laser chip can be sealed if a separate resin cap is mounted to the resin molding, so the laser chip can be protected favorably against humidity and the like in the external atmosphere. It is also preferable to provide the heat-radiating fin to the back side of the lead frame. When mounting to the device housing is taken into account, it is preferable for the heat-radiating fin to be exposed on the side of at least one of the two end faces of the flange and in roughly the same plane as the end face corresponding to the flange. 
     The lead frame and the heat-radiating fin may also be formed integrally. The heat-radiating fin may also consist of a plurality of parts. 
     If a wiring lead frame is provided to the side of the lead frame on which the laser chip is mounted, and a convex component is provided at a location on the rear end face of the resin molding where the lead frame protrudes, then when metal parts are arranged around the lead frame during the mounting of the resin molding to the device, short circuits between these metal parts and the lead frame can be prevented. 
     According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor laser device, in which a laser chip that emits laser light is mounted on the surface of a lead frame that is parallel to the optical axis, a heat-radiating fin for cooling the laser chip is provided to the lead frame, and part of the lead frame is sealed with a resin molding having a main body, wherein this method for manufacturing a semiconductor laser device is such that, first, part of the lead frame having the heat-radiating fin is sealed with the resin molding, after which the laser chip is mounted at a specific site on the lead frame where there has been no sealing with the resin molding. 
     Therefore, according to this second aspect, the semiconductor laser device according to the above-mentioned first aspect can be manufactured with good precision. Specifically, since the laser chip can be mounted to the lead frame after the resin molding has been injection molded, the laser chip is not subjected to the high temperature and pressure entailed during injection molding. Therefore, deterioration and breakage of the laser chip can be prevented. 
     Since the laser chip can be sealed if a separate resin cap is mounted to the resin molding, the laser chip can be protected favorably against humidity and the like in the external atmosphere. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, advantages and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 a  to  1   c  constitute a three-view diagram of the structure of the semiconductor laser device in one embodiment of the present invention, with FIG. 1 a  being a plan view, FIG. 1 b  being a front view, and FIG. 1 c  being a cross sectional view; 
     FIGS. 2 a  and  2   b  are exploded oblique views of the structure of the semiconductor laser device; 
     FIGS. 3 a  and  3   b  constitute a two-view diagram of the state in which the semiconductor laser device has been attached to the device housing, with FIG. 3 a  being a cross sectional view, and FIG. 3 b  a rear view; 
     FIG. 4 a  is a graph of the optical output characteristics of the semiconductor laser device in one embodiment of the present invention, and 
     FIG. 4 b  is a graph of the optical output characteristics of a conventional can type of semiconductor laser device; 
     FIG. 5 is a flow chart of the semiconductor laser device manufacturing method in one embodiment of the present invention; 
     FIGS. 6 a - 6   c  are step diagrams illustrating the method for manufacturing the heat-radiating fin used in the semiconductor laser device in one embodiment of the present invention; 
     FIG. 7 is an oblique view of the injection molding apparatus used to form the resin molding in the semiconductor laser device in one embodiment of the present invention; 
     FIG. 8 is a schematic diagram of the resin powder that serves as the material of the resin molding; 
     FIG. 9 is a cross sectional view of the structure of the metal mold; 
     FIGS. 10 a - 10   e  are cross sectional views of the step for molding the resin molding; 
     FIGS. 11 a - 11   c  are step diagrams illustrating a variation example of the method for manufacturing the heat-radiating fin; 
     FIGS. 12 a - 12   b  are exploded oblique views of the structure of the semiconductor laser device in another embodiment of the present invention; 
     FIG. 13 is an oblique view of the structure of a conventional can type of semiconductor laser device; 
     FIG. 14 is a cross section of the state in which this can type of semiconductor laser device has been attached to the device housing; 
     FIGS. 15 a - 15   b  are a two-view diagram of the structure of a conventional resin molding type of semiconductor laser device; and 
     FIG. 16 is an oblique view of the structure of another conventional resin molding type of semiconductor laser device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described through reference to the figures. 
     In these embodiments, the same names and numbers will be used to refer to those structural components that are the same as in the conventional semiconductor laser device discussed above. 
     First, with the semiconductor laser device  31  in this embodiment, as shown in FIG. 1, the laser chip  2  is mounted to the surface of a lead frame  33  parallel to the optical axis via a heat sink  32 . This lead frame  33  is sealed with a resin molding  36  along with wiring lead frames  34  and  35 . 
     This resin molding  36  is formed in a shape such that a flange  38  sticks out around the outside at the end of the main body  37 , and is formed in the same shape as the so-called can type of semiconductor laser device  1 . A separate L-shaped heat-radiating fin  39  is integrally mounted on the rear side of the lead frame  33 , and this heat-radiating fin  39  is sealed with the resin molding  36  in a state in which it is exposed on both of the end faces  40  and  41  of the flange  38 . 
     As shown in FIG. 2, this resin molding  36  is formed here in a shape such that the laser chip  2  is exposed, and a separate resin cap  42  is integrally mounted here, which seals the laser chip  2 . The resin cap  42  is formed from a colorless, transparent, acrylic or epoxy resin that transmits laser light well, and is formed in an L shape such that the two flat panels are joined at a right angle. The location where the laser light is transmitted is covered with an AR coating as a surface treatment for increasing transmissivity. 
     A photodiode  43  is mounted to the rear (in the optical axis direction) of the laser chip  2 , and this photodiode  43  and the laser chip  2  are wired to the lead frames  34  and  35 , respectively. The resin molding  36  has a convex component  45  formed on its rear end face  41 , and the lead frames  32  to  34  protrude from the location of this convex component  45 . The portions of the lead frames  32  to  34  located inside the resin molding  36  are called inner leads  46 , and the portions of the lead frames  32  to  34  protruding from the resin molding  36  are called tie bars  47 . 
     The flange  38  of the resin molding  36  is formed such that the outer peripheral surface thereof is cylindrical and concentric with the optical axis of the laser chip  2 , but a single flat surface  49  that is parallel to the surface of the lead frame  33 , and a pair of flat surfaces  50  that are perpendicular to the surface of the lead frame  33  are formed as parts of this flange  38 . 
     With the structure described above, since the semiconductor laser device  31  in this embodiment is equivalent to a conventional can type in terms of the shape of the resin molding  36 , mounting to the device housing  8  is possible in the same manner as with a conventional can type, as shown in FIG.  3 . 
     The semiconductor laser device  31  in this embodiment has the heat-radiating fin  39  provided to the rear face of the lead frame  33 , which has the laser chip  2  mounted on the front side, and the heat-radiating fin  39  is exposed on both of the end faces of the flange  38  of the resin molding  36 , so the heat generated by the laser chip  2  is radiated well and the laser light can be emitted more stably. In particular, when the metal device housing  8 , a holder  51 , or the like touches the end face of the flange  38 , the heat-radiating fin  39  comes into contact with these, which makes possible the favorable radiation of the heat generated by the laser chip  2 . 
     In view of this, a prototype of the semiconductor laser device  31  discussed above was actually produced, and a test was conducted for thermal radiation along with the conventional can type of semiconductor laser device  1 , whereupon, as shown in FIG. 4, it was confirmed that the semiconductor laser device  31  of this embodiment allows for thermal radiation equivalent to that of a conventional can type, despite its being a resin molding type. 
     The details of this test will now be described. First, the semiconductor laser devices  1  and  31  were each installed in an aluminum block, and the aluminum block was placed on a hot plate (not shown). Here, with the semiconductor laser device  31 , the heat-radiating fin  39  was in contact with the aluminum block. The aluminum block was then heated by the hot plate to 25° C., 50° C., 60° C., 70° C., and 77° C., a current was applied to the semiconductor laser devices  1  and  31  in each of these states, and the current was raised until the output of laser light from each device reached the specified approximately 30 mW. It was confirmed that with both of the semiconductor laser devices  1  and  31 , a large current was required to generate the specified optical output at high temperatures, and at a small current a high degree of thermal radiation was required in order to output laser light at a high level of efficiency. Graphs of the relationship between optical output and current value for the semiconductor laser devices  1  and  31  at the various temperatures were compared, whereupon it was confirmed that these relationships were equivalent, as shown in FIGS. 4 a  and  4   b.    
     In other words, the semiconductor laser device  31  in this embodiment, despite being a resin molding type, is capable of thermal radiation that is equivalent to that of the conventional can type of semiconductor laser device  1 . This means that the heat generated by the laser chip  2  is conducted favorably to the aluminum block by the heat-radiating fin  39 . 
     Furthermore, as mentioned above, the semiconductor laser device  31  in this embodiment is mounted with the flange  38  of the resin molding  36  in the stepped hole  9  of the device housing  8 , but because of the high precision in the relative positioning of the laser chip  2  and the shape of this flange  38 , the laser light can be emitted more accurately with respect to the device housing  8 . In other words, when the  36  is formed, the lead frame  33 , on the front of which is mounted the laser chip  2 , can be positioned by means of the heat-radiating fin  39  on the rear side, so the laser chip  2  can be put in the proper position with respect to the shape of the resin molding  36  (this will be discussed in more detail below). 
     In particular, since the outer peripheral surface  48  of the flange  38  is formed as a cylinder that is concentric with the optical axis of the laser chip  2 , if the semiconductor laser device  31  is mounted in the device housing  8  with the flange  38  just as with a conventional can type, then the laser light of the laser chip  2  can be emitted to the same location as with a conventional can type, and there is no need to set the angle during mounting. 
     Since a pair of flat surfaces  50  that are parallel to each other are formed on the outer peripheral surface  48  of the flange  38  of the resin molding  36 , an assembly manipulator (not shown), for example, can easily hold the resin molding  36  at the location of the flat surfaces  50 , which allows the work of attaching the resin cap  42  to the resin molding  36 , or the work of attaching the semiconductor laser device  31  to the device housing  8 , to be carried out more efficiently. Furthermore, since these flat surfaces  50  are formed in the direction perpendicular to the front of the lead frame  33 , it is easier to take the injection-molded resin molding  36  out of the metal mold, as will be described in more detail below. 
     Also, when the semiconductor laser device  31  in this embodiment is fixed to the device housing  8  with the annular holder  51  as shown in FIG. 3, since a convex component  45  is formed on the rear end face  41  of the  36  at the location where the lead frames  33  to  35  stick out, there will be no short circuiting of the lead frames  33  to  35  even if the holder  51  is made of metal. In addition, with the semiconductor laser device  31  of the above structure, since the heat-radiating fin  39  is exposed on both sides of the flange  38  of the resin molding  36 , the heat-radiating fin  39  can be brought into contact with both the device housing  8  and the holder  51 , and extremely good thermal radiation will be displayed. 
     Next, the method for manufacturing the semiconductor laser device  1  with the structure described above will be described through reference to FIGS. 5 to  10 . First, as shown by step SP 1  in FIG. 5, the lead frames  33  to  35  and the heat-radiating fin  39  are produced individually. For instance, three lead frames  33  to  35  are formed by the etching or pressing of thin metal sheets, at the location of the tie bars  47 , initially in a state of being integrally linked to each other. 
     Because the heat-radiating fin  39  is so thick, it is difficult to produce by the etching or pressing of a metal sheet, so it is produced by drawing, for example (step SP 2 ). In this case, as shown in FIG. 6 a , a metal mold  53 , in which an L-shaped opening  52  has been formed corresponding to the heat-radiating fin  39 , is readied for drawing, and as shown in FIG. 6 b , a member  54  having an L-shaped cross section is formed by drawing in this metal mold  53 , and as shown in FIG. 6 c , this member  54  is cut to a thickness of about 1.0 mm. This allows a large number of heat-radiating fins  39  to be produced with ease. 
     The heat-radiating fin  39  produced in this manner is fixed with an adhesive having good thermal conductivity, such as silver paste, to the rear of the lead frame  33 , to which the lead frames  34  and  35  have been integrated (step SP 3 ), and this product is sealed with the resin molding  36  (step SP 4 ). In this case, as shown in FIG. 7, a stationary metal mold  55  and a movable metal mold  56  corresponding to the resin molding  36  are readied, and these are set in an injection molding apparatus  57 . Next, as shown in FIG. 8, an epoxy (for example) resin powder  58  is readied, and this is fed into the injection molding apparatus  57 . 
     As shown in FIG. 9, concave components  61  and  62  are formed in the metal molds  55  and  56  so as to form a cavity  60  whose shape corresponds to the resin molding  36 . In particular, the stationary metal mold  55  has a slide component  63  formed at a location that closes off the concave component  62 . The concave component  62  of the stationary metal mold  55  is formed such that the heat-radiating fin  39  is held at the location closed off by the slide component  63 , so, as shown in FIGS. 10 a  and  10   b , the lead frames  33  to  35  are positioned by the heat-radiating fin  39  in the concave component  61  of the stationary metal mold  55  here. 
     As shown in FIG. 10 c , the movable metal mold  56  is joined with the stationary metal mold  55  in this state, and molten resin  64  is injected into the cavity formed by the concave components  61  and  62  of these metal molds  55  and  56  as shown in FIGS. 10 d  and  10   e . As a result, the lead frame  33 , to which the heat-radiating fin  39  is fixed, is insert-molded in the resin molding  36  along with the lateral lead frames  34  and  35 , and the resin molding  36  is subsequently taken out by separating the movable metal mold  56  from the stationary metal mold  55 . 
     At this point, the resin molding  36  is pushed out of the concave component  61  by a slide pin  65  provided to the movable metal mold  56 , but since this slide pin  65  strikes the flat surface  40  of the flange  38  of the resin molding  36 , the slide pin does not damage the shape of the resin molding  36 . Also, the pair of flat surfaces  50  that are parallel to each other are formed on both sides of the flange  38  of the resin molding  36 , but since these flat surfaces  50  are formed parallel to the direction in which the metal molds  55  and  56  are separated, the resin molding  36  can be taken out of the metal molds  55  and  56  with ease. Furthermore, since the lead frames  33  to  35  are accurately positioned inside the cavity  60  of the metal molds  55  and  56  by the heat-radiating fin  39  as discussed above, the resin molding  36  is molded in the proper shape with respect to the position of the front of the lead frame  33 . 
     Since the lead frames  33  to  35  are thus sealed by the resin molding  36  in the molding, the inner leads  46  of the lead frames  33  to  35  are ideally exposed in the inside of the resin molding  36  in this state. However, since resin flash is produced on this surface, the flash is removed in this case as shown in step SP 5  in FIG.  5 . Next, the tie bars  47  of the lead frames  33  to  35  that stick out from the resin molding  36  are cut off (step SP 6 ), and the inner leads  46  and tie bars  47  of the lead frames  33  to  35  are covered with a metal or other plating layer (step SP 7 ). 
     The separately readied laser chip  2  and photodiode  43  are mounted on the metal heat sink  32  (step SP 8 ), and this heat sink  32  is fixed to the inner lead  46  of the above-mentioned lead frame  33  with an adhesive that has good electrical and thermal conductivity, such as silver paste (step SP 9 ). Next, the laser chip  2  is wired to the inner lead  46  of the lead frame  33 , and the photodiode  43  to the inner lead  46  of the lead frame  35 , by ultrasonic fusing or hot press bonding of a metal bonding wire  44  (step SP 10 ). 
     The resin cap  42  is individually produced by the injection molding of an acrylic or epoxy resin (step SP 11 ), and this resin cap  42  is coated with an AR (anti-reflective) coating as a surface treatment. This resin cap  42  is fixed to the above-mentioned resin molding  36  with a photosetting adhesive or the like (step SP 12 ), and the tie bars  47  of the lead frames  33  to  35  are cut to the required length (step SP 13 ) to complete the semiconductor laser device  31 . 
     Thus, according to the manufacturing method of this embodiment, the laser chip  2  and resin cap  42  are mounted to the lead frame  33  after the injection molding of the resin molding  36 , so the laser chip  2  and the like are not subjected to the high temperature and pressure entailed by injection molding, and deterioration and damage of the laser chip  2  and the like can therefore be prevented. Since the laser chip  2  and the photodiode  43  are sealed by mounting the separate resin cap  42  on the resin molding  36 , the laser chip  2  and the like can be protected well against humidity and so on in the external atmosphere. 
     Since this resin cap  42  is formed in a simple L shape, it can be produced easily, and therefore can be fixed accurately to the resin molding  36 , so the laser chip  2  and the like can be sealed favorably, and since the portion facing the laser chip  2  is flat, it does not hinder the transmission of laser light. Furthermore, since the resin cap  42  is surface treated with an AR coating that enhances the transmissivity of laser light, the semiconductor laser device  31  is able to emit the laser light more efficiently. Further, since the resin cap  42  is formed from an acrylic or epoxy resin, it can be produced easily using an ordinary resin as the material, and if this material is the same as that of the resin molding  36 , then peeling caused by differences in thermal expansion can be prevented. 
     The present invention is not limited to the above embodiment, and various permutations are possible to the extent that the essence of the invention is not exceeded. For example, in the above embodiment the heat-radiating fin  39  was produced by cutting the member  54  drawn to the specified cross sectional shape in the metal mold  53 , but it is also possible to use a wire cutter or laser cutter to cut off the heat-radiating fin  39  from a metal sheet  66  of the specified thickness. 
     Also, in the above embodiment the heat-radiating fin  39  was produced as a single part, but it is also possible to produce this heat-radiating fin  39  from a plurality of parts. For instance, if the heat-radiating fin  39  has an L-shaped cross section as above, then it can be fabricated by joining long and short sections. When the heat-radiating fin  39  is produced as a single part, and when it is produced as a plurality of parts, the productivity, thermal conductivity, and various other considerations will be mutually conflicting, so the selection should be made after consideration of the required performance and the cost. 
     In addition, in the above embodiment the lead frame  33  and the heat-radiating fin  39  were formed separately and then integrally joined, but it is also possible for the lead frame and the heat-radiating fin to be formed integrally from the outset. An integral part such as this is not as easy to produce as separate components, but it allows thermal conductivity to be improved, so this selection of structures should also be made after consideration of performance and cost. 
     Also, with the semiconductor laser device  31  in the above embodiment, the resin cap  42  was formed as a simple L shape and was joined to the box-shaped portion of the resin molding  36 , but it is also possible to mold a resin cap  72  and a resin molding  73  in shapes such that the above-mentioned box-like portion is diagonally truncated, and then integrally join these at the diagonal location, as with the semiconductor laser device  71  shown in FIG.  12 . With this structure, there is a decrease in productivity because of the more complicated shape of the resin cap  72 , but deformation of the resin can  72  as a result of changes over time, for example, can be prevented, and this allows the durability and reliability of the semiconductor laser device  71  to be improved. 
     It is thus apparent that the present invention is not limited to the above embodiments but may be changed and modified without departing from the scope and spirit of the invention. 
     Finally, the present application claims the priority of Japanese Patent Application No. Hei9-005489 filed Jan. 16, 1997, which is herein incorporated by reference.