GB2284934A

GB2284934A - Semiconductor laser

Info

Publication number: GB2284934A
Application number: GB9425120A
Authority: GB
Inventors: Shoji Kitamura; Yoichi Shindo
Original assignee: Fuji Electric Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 1993-12-14
Filing date: 1994-12-13
Publication date: 1995-06-21
Anticipated expiration: 2014-12-13
Also published as: TW373828U; FR2713828B1; GB2284934B; FR2713828A1; JPH07170019A; GB9425120D0; DE4444618A1

Description

1 2284934 SEMICONDUCTOR LASER The present invention relates to

semiconductor lasers, and more specifically a sealing resin layer for sealing a laser diode element (hereinafter simply referred to as an LD) of a semiconductor laser.

Semiconductor lasers are used in various optical devices and apparatus such as optical disk storage devices including compact disk storage devices (hereinafter simply referred to as CD), laser beam printers, etc. (hereinafter simply referred to as apparatus or optical apparatus).

The semiconductor laser art includes a well known canned semiconductor laser, shown schematically in Figures 5a and 5b which illustrate a configuration and mounting of the canned semiconductor laser. As shown in the cutaway perspective view in Figure 5a, an LD element, comprises an LD chip 1 and a sub-mount layer 2 as a heat radiator plate, is soldered to a radiator block 4 protruding upward from a base 3. A cap 6, having a glass window 5 in its top surface, is soldered to the base 3 to cover and protect the LD chip 1. Figure 5b is a sectional view showing installation of the semiconductor laser on an optical apparatus 7. The cap 6 is inserted into a slot or opening 8 of the apparatus 7. In Figure 5b, a laser beam is emitted in a direction indicated by the arrow 9.

Figure 6a is a plan view of the laser diode and Figure 6b is a sectional view taken along the line A-A of Figure 6a. In Figures 6a and 6b, the same parts as those in Figures 5a and 5b are designated by the same reference numerals. As shown in Figure 6a, the laser beam emitting point of the laser diode should be kept at a predetermined point. The LD chip is arranged so that its laser beam emitting point is positioned at the intersection 10 of two diameters of the base 3 and the glass window 5, one diameter, the X-axis, being perpendicular to a major surface of the radiator body 4, and the other diameter, the Y-axis, parallel to the major surface of the radiator body 4. The arrangement of the sub-mount 2 and the radiator 2 body 4 is thus determined. As shown in Figure 5b, the semiconductor laser is installed in an apparatus 7 usually by inserting the cap 6 into the opening 8 and by adhesion or pressurised-bonding of a flange portion 3a of the base 3 to the apparatus 7. The location of the laser beam emitting point is defined by the outer periphery and upper face of the flange portion 3a. The shape and dimensions of the semiconductor laser including the flange portion 3a have been standardised so as to avoid changes of design and parts of the apparatus into which the semiconductor laser is incorporated. For example, an outer diameter of the most popular semiconductor laser with low output power of 3 to 5 mW for use in the CD apparatus is specified at 5.6 m, and an outer diameter of the high output power semiconductor laser at 9 m.

A semiconductor laser to be developed should be one which can be handled in the same way as the conventional semiconductor lasers to avoid the need for the aforementioned changes of design and parts of the apparatus. That is, the new semiconductor laser should conform with the conventional one in its installation mechanism and in the location of the laser beam emitting point. In addition, the new semiconductor laser should be cheaper than the conventional one. Recently, a resin-sealed type (moulded type) semiconductor laser has been developed which is cheaper than the conventional canned semiconductor laser. The moulded semiconductor laser allows more freedom in designing its shape and dimensions than does the canned one.

Figure 7 is a perspective view showing the aforementioned moulded semiconductor laser disclosed in Japanese Laid Open Patent Publication H02-125687 and in Japanese Laid Open Patent Publication H02-125688. In Figure 7, the moulded semiconductor laser comprises an LD chip 1 mounted on a sub-mount layer 2. A cylindrical sealing resin layer 11, made for example of transparent epoxy resin, surrounds the LD chip 1 and the submount layer 2. The sealing resin layer 11 further includes a cylindrical flange portion lia corresponding to the flange portion 3a of the base 3 in the canned 3 semiconductor laser. The moulded semiconductor laser is driven via connecting leads 12 and gold connecting wires 13. Resin moulding has been applied to light sources with low beam density per unit area such as light emitting diodes (LEDs). Figure 8 is a schematic sectional view showing the structure of the LD chip 1. In Figure 8. the LD chip 1 has a double hetero (DH) structure which is composed of an n-type GaAs substrate 14, an n-type A1GaAs cladding layer 15, a GaAs active layer 16, a p-type cladding layer 17, and a p-type cap layer 18. A top surface of the p-type cap layer 18 (major face of the LD chip) is covered with an electrode 19 and the bottom surface of the GaAs substrate 14 with.a back electrode 20.

Figure 9 is a sectional view of the LD chip 1 taken along A-A of Figure 8. In Figure 9, the same parts as those in Figure 8 are designated by the same reference numerals. As shown in Figure 9, the LD chip 1 further comprises protective layers 22 formed on end faces 21 from which the laser beam 9 is emitted. The protective layers 22 are formed to protect the end faces 21 from breakdown. The protective layers 22 are made for example of silicone, which shows a low optical absorption coefficient in the wavelength range of the laser beam 9, and high thermal endurance. The protective layers 22 prevent the properties of the semiconductor laser from deterioration caused by optical damage of the sealing resin layer 11. The protective layers 22, inserted between the end faces 21 of the LD chip 1 and the sealing resin layer 11, attenuate laser beam density in the sealing resin layer 11 and prevent the sealing epoxy layer 11 from being optically damaged by the laser beam 9.

The resin moulding for the semiconductor lasers described above is well suited for reduced cost and for providing greater freedom in the design of the semiconductor lasers. The resin moulding technique is applicable also to laser diodes with high beam density. A resin-moulded semiconductor laser such as that of Figure 7 which has the same shape as a conventional canned semiconductor laser is well suited for installing in optical apparatus.

4 Figures 10a and 10b show a main portion of the resin-moulded semiconductor laser of Figure 7, in which Figure 10a is a front plan view and Figure 10b is a sectional view taken along the line A-A of Figure 10a. In Figures 10a and 10b, parts corresponding to parts in Figure 7 are designated by the same reference numerals. In Figure 10a, the LD chip 1 is positioned in the centre of the sealing resin layer 11 at an intersection 10 of an X-axis (perpendicular to the major face of the LD chip 1) and a Y-axis (parallel to the major face of the LD chip 1) similarly to the canned semiconductor laser (see Figure 6a). A centre 23 of the connecting lead 12 is displaced by an offset distance AX,ce inevitably determined by the position of the LD chip 1, the thickness of the sub-mount layer 2 and the thickness of the connecting leads 12. Explanations with reference to Figure 10b will be omitted to avoid duplication.

The structure of the semiconductor laser shown in Figures 10a and 10b suffers from two major problems, which will be described below. Firstly, the laser beam emitting point moves from its original position as the temperature of the resin around the LD chip 1 rises, this rise being caused by power supply to the LD chip 1 or by a temperature rise of the environment. Secondly, the sealing resin layer 11 peels away from the protective layer 22. This peeling-off causes deterioration of beam radiation characteristics (far field pattern characteristics: FFP characteristics).

Now, the first problem can be explained in more detail., with reference to Figure 11, which displacement of the laser beam emitting point is examined. Figure 11 is a graph showing the relation between the displacement of the laser beam emitting point along the X-direction shown in Figure 10a and the operation time of the semiconductor laser. In Figure 11, a single-dotted chain line represents the displacement in the cylindrical resin-moulded semiconductor laser described above and a solid line represents the displacement of the emitting point in a flat resinmoulded semiconductor laser arrangement, to be described later.

As Figure 11 shows, the emitting point of the laser beam is displaced along the X-direction when the semiconductor laser of Figure 10 is driven with a current of 50 mA at room temperature. As shown in Figure 11, the laser beam emitting point is displaced by 0.5 pm in the X direction (X is taken to be positive to the right as seen in Figure 10a) in 2 minutes after the laser diode is turned on and returns to the original position in 2 minutes after the laser diode is turned off. When this semiconductor laser is incorporated, for example, into an optical pickup for a CD storage device, trouble is caused in the CD storage device immediately after the semiconductor laser is turned on or by temperature change of the environment.

The inventors of this invention have found that the displacement of the laser beam emitting point corresponds to the displacement of the connecting leads 12 in the X direction by thermal expansion of the sealing resin layer 11 which is caused by heat generated either from the LD chip 1 or by a temperature change of the environment. This displacement of the connecting leads 12 by thermal expansion of the sealing resin layer is closely related to the offset 24 of AX.te of the connecting leads 12 from the centre 10 of the sealing resin layer 11 shown in Figure 10. However, the offset AX,ef affects the displacement of the laser beam emitting point because of the thermal expansion of the sealing resin layer 11 in the region near to the LD chip 1. The thermal expansion of the sealing resin layer 11 in the region remote from the LD chip 1, for example thermal expansion of the flange portion lla of Figure 10, does not cause the displacement of the laser beam emitting point from its original position.

It is necessary, to avoid the displacement of the laser beam emitting point, to form the sealing resin layer 11 so as to place the connecting leads 12 at the centre of symmetry of the sealing resin layer 11. If one considers a cross section of a top portion of a central connecting lead 12a taken in a plane parallel to the front laser beam emitting face of the LD chip 1, it is enough to form the sealing resin layer 11 at least near to the main portion of the LD 6 chip 1 symmetrically in volume with respect to a centre line parallel to the y-axis of the top portion of the central connecting lead 12a. That is, it is necessary to form the sealing resin layer 11 so that the centre 10 of the sealing resin layer 11 coincides with the centre 23 of the top portion of the central connecting lead 12a, though it is not always necessary to form the sealing resin layer 11 symmetrically in its portions away from the LD chip 1 or the connecting leads 12.

The peeling-off problem referred to above is practically solved by forming the sealing resin layer 11 symmetrically with respect to the connecting leads 12 as described above and in the form of a thin flat plate.

Figure 12 is a schematic perspective view showing a flat resin-moulded semiconductor laser disclosed in Japanese Laid Open Patent Publication H02-125687. This semiconductor laser facilitates relieving stress caused by thermal expansion of the resin by reducing the volume of the resin which extends around the protective layer 22 and by equalising the sealant resin volume around the LD chip 1.

Table 1 compares electrical and optical properties measured at predetermined cycles of a heat cycle test conducted on a test specimen of a cylindrical resin-moulded semiconductor laser as shown in Figure 7 and a test specimen of a thin flat resin-moulded semiconductor laser as shown in Figure 10. In both sample semiconductor lasers, the protective layers 22 were made of gummy organosilicon resin containing dimethylsiloxane as its main component. The heat cycle test repeated one heat cycle consisting of heating at 850C for 30 minutes, rapid cooling down to - 40c1C, and keeping at 400C for 30 minutes followed by return to 850C.

7 Table 1 Result of the heat cycle test Shape of 1 1 Number of heat cyclesi 1Specimen No.i sealing 1 Content of fault 1 1 1 resin layerl 1 1 1 1 1 1001 2001 3001 400 1 1 1 1 1 1 1 1 1 1 FFP deteriorationi 0 1 5 1 8 1 12 1 1 M1 1 1 1 1 1 Cylindricall 1 1 1 1 L 1 Fault other than 1 0 1 0 1 0 1 0 1 1 ?FP deteriorationi 1 1 1 1 1 FFP deteriorationi 0 1 0 1 0 1 0 1 1 (%) 2 1 Flat L 1 Fault other than 1 0 1 0 1 0 1 0 1 1 FFP deteriorationi 1 1 1 1 1 (%) 1 As listed in Table 1, the far field pattern (M) of the laser beam from the cylindrical resin-moulded semiconductor 'Laser of Figure 7 deteriorated during the heat cycle test. However, no fault was not observed on the thin flat resin-moulded semiconductor laser of Figure 12. The observed far field pattern (M) deterioration was caused by peeling-off between the protective layer 22 and the sealing resin layer 11. Thus, the thin flat resin-moulded semiconductor laser prevents peeling-off of the resin layers.

In this thin flat resin-moulded semiconductor laser, no displacement of the laser beam emitting point occurred as shown in Figure 11.

As described above, the resin-moulded semiconductor laser is well suited for cost reduction irrespective of whether its sealing resin layer is cylindrical or thin and flat. Though the cylindrical resin- moulded semiconductor laser is easily mounted in an apparatus, as is the canned semiconductor laser, by means of the flange portion formed as a part of the sealing resin layer, the sealing resin layer is bulky and asymmetrical with respect to the centre line of t.'he 8 connecting leads. This asymmetry generates stress by temperature change and causes FFP deterioration by displacement of the laser beam emitting point. The thin flat resin-moulded semiconductor laser, the sealing resin layer of which is small in volume and symmetrical with respect to the centre line of the connecting lead, solves the problem described above. However the conventional thin flat resin-moulded semiconductor laser cannot be mounted in an apparatus in the same way as the canned semiconductor laser, since the conventional thin flat resin-moulded semiconductor laser lacks the flange portion. Thus, the cylindrical and the thin flat resin-moulded semiconductor lasers accompany the problems which are in trade-off relation to each other.

In view of the foregoing, an object of the present invention is to provide a resin-moulded semiconductor laser which is as easily mounted in an apparatus as the canned semiconductor laser and eliminates both displacement of the laser beam emitting point and peeling-off of the resin layers.

The object of the present invention is achieved by a semiconductor laser which comprises a laser diode chip, connected with a connecting means (connecting leads) through a sub-mount layer, for emitting a laser beam; and a sealing resin layer or body transparent to the laser beam and closely surrounding the connecting means and at least a main portion of the laser diode chip, in which the sealing resin body further comprises a flat portion covering at least the main portion of the laser diode chip; and at least one flange portion integrated with the flat portion and covering a terminal portion of the connecting means at which the connecting means is connected with an apparatus into which the semiconductor laser is incorporated. The flat portion may further comprise top and bottom surfaces arranged symmetrically with respect to a horizontal axis which crosses a centre of the connecting means (alignment of the connecting leads) defined by a position of the laser diode chip and side faces arranged symmetricall with respect to a vertical axis y which crosses the centre of the connecting means. The at least one flange portion may further comprise a peripheral surface, the centre of curvature of which coincides with a iaser beam emitting point of the laser diode chip.

9 In the semiconductor laser according to the present invention, the flat portion of the sealing resin layer is formed in such a way that, at least around the main portion of the LD chip, its top and bottom surfaces are symmetrically arranged with respect to a horizontal central plane of the connecting means extending parallel to the alignment of the connecting leads, and both side faces are symmetrically arranged with respect to a vertical centre line of the connecting means (perpendicular to the alignment of the connecting leads). Therefore, this configuration of the flat portion suppresses generation of stress caused by thermal expansion difference between the sealant resin and the connecting leads and prevents the laser beam emitting point from displacing. In addition to this, the outer peripheral surface of the flange portion of the sealing resin layer has a centre of curvature which coincides with the laser beam emitting point of the LD chip. Since the curvature of the outer peripheral surface can be set at the curvature of the flange portion of the canned semiconductor laser, the configuration of the flange portion facilitates incorporating the semiconductor laser of the present invention into apparatus in which the semiconductor laser is used.

Now the present invention will be described in detail hereinafter with reference to the accompanied drawings, in which:

Figure la is a front plan view schematically showing a structure of a main portion of the semiconductor laser according to the present invention; Figure 1b is a top plan view of the main portion of the semiconductor laser of Figure!a; Figure 2 is a perspective view schematically showing a typical external appearance of the resin-moulded semiconductor laser according to the present invention; Figure 3a is a sectional view of the cylindrical laser guide of an optical pickup for CD on which the resin-moulded semiconductor laser of the present invention is mounted; Figure 3b is a plan view of the cylindrical laser guide seen from the top of the mounted resin-moulded semiconductor laser; Figure 3c is a sectional view of the cylindrical laser guide on which the conventional canned semiconductor laser is mounted; Figure 3d is a plan view of the cylindrical laser guide 28 seen from the top of the mounted canned semiconductor laser; Figures 4a, 4b and 4c are perspective views schematically showing different external appearances of the resin-moulded semiconductor laser according to the present invention; Figure 5a is a perspective view schematically showing a configurati.on of the conventional canned semiconductor laser; Figure 5b is a sectional view showing mounting of the conventional canned semiconductor laser; Figure 6a is a front plan view of a laser diode; Figure 6b is a sectional view taken along A-A of Figure 6a; Figure 7 is a perspective view showing the conventional resin-moulded semiconductor laser; Figure 8 is a sectional view schematically showing the structure of an LD chip; Figure 9 is a sectional view of the LD chip taken along A-A of Figure 8; Figure 10a is a front plan view showing a main port-lon of the resin- moulded semiconductor laser of Figure 7; Figure 10b is a sectional view taken along A-A of Figure 10a; Figure 11 is a graph showing the relationship between the displacement of the laser beam emitting point along the X-direction shown in Figure 10a and the operation time of the semiconductor laser; and Figure 12 is a perspective view schematically showing the conventional flat resin-moulded semiconductor laser.

Referring now to the drawings, Figure la is a front plan view schematically showing the structure of a main portion of the semiconductor laser according to the present invention and Figure lb is a top plan view. The parts corresponding to those in the drawing figures already explained are designall-ed. by the same reference numerals.

The semiconductor laser comprises an LD chip 1, the end faces of which are covered with protective layers (not shown), connected with a connecting means 12 through a sub-mount layer 2. In Figure lb, the connecting means 12 further comprises three connecting leads aligned in a plane, called the lead plane. A central connecting lead 12a is longer than the other two and its top portion is enlarged sideways to extend beyond the ends of the other two connecting leads in the lead plane. The LD chip 1 is mounted on the sub-mount layer 2, which is itself mounted on the enlarged top portion of the central connecting lead 12a. A sealing layer of transparent epoxy resin (sealing resin layer) comprises a flat portion 25 and two part-cylindrical flange portions 26 integrally moulded with the flat portion 25. The flat portion 25 covers at least a main portion of an LD element including the LD chip 1. The partcylindrical flange portions 26 protrude sideways from the flat portion 25 at the junction of the connecting leads 12 with the sealing layer. The arcuate peripheral surfaces of the part-cylindrical flange portions 26 have a predetermined common radius of curvature.

The flat portion 25 of the sealing resin layer of the present invention corresponds in its main structure with the sealing resin layer 11 of Figure 12. The centre of the flat portion 25 coincides with the centre 23 of the top portion of the central connecting lead 11.a. The top and bottom surfaces of the flat portion 25 are arranged in symmetrical locations in width direction (Y-direction) with respect to the centre 213, and the side faces of the flat portion 25 are arranged in symmetrical locations in thickness direction (X-direction) with respect to the centre 23. By this arrangement, the thickness of the epoxy layer above the top portion of the connecting lead 12a as seen in Figure la is equal to the thickness below it, and the thicknesses of the epoxy laYer on either side of the top portion are also equal. Thus, stress generation caused by thermal expansion differences between the sealant resin and the connecting leads 12 is suppressed.

12 The configuration of the flange portion 26 almost coincides with the flange portion lla of the sealing resin portion 11 of, Figures 7 and 10. The centre of curvature of the arcuate outer surfaces of the flange portions 26 coincides with the laser beam emitting point 27 of the LD chip 1, and the outer periphery of the flange portion 26 lies on a virtual circle represented by a broken line. The radius of curvature of this virtual circle, i.e. the radius of curvature of the flange portion 26, is determined so that the flange portion 26 facilitates mounting of the resin-moulded semiconductor 'laser on an apparatus as the flange portion lla of the canned semiconductor laser.

Figure 2 is a perspective view schematically showing a typical external appearance of the resin-moullded semiconductor laser according to the present invention.

Figures 3a to 3d include a sectionall view and a plan view of a cylindrical laser guide 28 of an optical pickup for CD on which the resinmoulded semiconductor laser of It-he present invention is mounted, for comparing it to the mounting of the conventional canned semiconductor laser. Figure 3a is a sectional view of the cylindrical laser guide 28 of an optical pickup for CD on which the resin-moulded semiconductor laser of the present invention is mounted; Figure 3b is a plan view of the cylindrical. laser guide ú18 seen from the left side of Figure 3a; Figure 3c is a sectional view of the cylindrical laser guide 1-8 on which the conventional canned semiconductor laser is mounted; and Figure 3d is an end view of the cylindrical laser guide 1-8 seen from the left side of Figure 3c.

Throughout these figures, the parts corresponding to those already described are designated by the same reference numerals. As has already been described, since the sealing resin layer of the resin-moulded semiconductor laser of the present invention is characterised by a flat portion 25, the centre of which coincides with the centre 23 of the connecting leads 12, and a flange portion or flange portions 26, the centre of which coincides with the laser beam emitting point 27 of the LD chip -1, the resin-moulded semiconductor laser of the present invention can be fixed to the laser guide 28 by means of the flange portion or flange portions 26 13 -or 'Laser. As in the same way as the conventional canned semiconduct has already been described, the flat portion of the sealing resin portion overcomes the problem pertinent to the sealing resin layer.

Though the mounting of the present resinmoulded semiconductor laser on the laser guide of a CD apparatus was explained as an example, it is obvious that the present resin-moulded semiconductor laser can be mounted on any apparatus on which the conventional canned semiconductor laser has been mounted. The external shape of the resin-moulded semiconductor laser of the present invention is not limited to that illustrated in Figure 2, but can be modified in various ways as needed.

Figures 4a, 4b and 4c are perspective views schematically showing different external appearances of the resin-moulded semiconductor laser according to the present invention. In Figure 4a, the part-cylindrical flange portions 26 are extended upwardly and downwardly compared with those of Figure 2. In Figure 4b, the flange portions 26 extend in the thickness di.r_ection of the flat portion 25. In Figure 4c, the resinmoulded semiconductor laser has a Ill-at cylindrical flange portion 26 and a groove 29 is formed on the periphery of the flange portion 26 to indicate the orientation of the LD chip. The resin-moulded semiconductor lase-rs shown in Figures 4a, 4b and 4c can be used in the same way as the canned type semiconductor laser. Since the resin-moulded semiconduct-or laser of the present invention is characterised by its symmetry around its LD chip 1 with respect to the connecting leads 12) and by a curved surface or curved surfaces around its -terminal portion, the centre of curvature of which coincides with the laser beam emitting point 27 of the LD chip 1, the shape and dimensions of the flange portlon can be changed so as to meet case by case requirements as far as the aforementioned specific feature is maintained.

As has been explained so far, the resin-moulded semiconductor laser of the present invention comprises a thin flat portion 25 symmet.rical with respect to the connecting leads 12; and a cylindrical flange portion or a number nf part-cylindrical flange portions, integral with the flat portion 2.S. Each flange port-lon Eurther comprises an arcuate outer peripheral surface, the centre of 14 curvature of which coincides with the axis of the laser beam emitted by the LD chip. This configuration of the present resin-moulded semiconductor laser effectively meets the conflicting requirements to the conventional cylindrical. and flat resin-moulded semiconductor lasers: the requirements include suppression of the displacement of the laser beam emitting point and provision of the same mounting mechanism as that of the canned semiconductor laser.

Though the conventional cylindrical resin-moulded semiconductor laser is easily mounted on the optical apparatus by means of a &flange corresponding to that of the canned semiconductor lasers, the sealing resin layer Is asymmetrically formed with respect to the connecting leads around the main portion of the LD element. This asymmetry causes asymmetric temperature distribution which furthe-- causes thermal stress. The thermal stress causes lateral displacement of the laser beam emitting point. Though the conventional flat resin-moulded semi-conductor laser facilitates suppressing thermal stress with its flat sealing resin laye,r symmetrically formed with respect to the connecting leads, the conventional flat resin-moulded semiconductor 'laser cannot. be mounted on optical apparatus in the same way as the canned semiconductor laser, since the flat resin-moulded semiconductor lase-r '-acxs the mounting mechanism provided in th.e canned semiconductor laser.

The sealing resin layer of the flat.-esin-moulded semiconductor laseraccording to tChe present invention comprises flat portion and a flange portion or flang-e portions. The flat 1. --- t, portion c2vers the main Portion of the LD element and is symmetrically formed with respect to the connecting leads. m-he flange portion covers the term':nal porton at which the se---conductor laser ils fixed to the optIcal apparatui- and is formed in varicus shape so as to be mountable on the optical apparatus in the same way as is the canned semiconducto.r laseIr. The flat portion and the flange portion or flange portions are integrally moulded into a sealing resin layer. The integrally moulded sealing resin layer thus facilitates suppressing lateral displacement of the laser beam em.;'-'--,ng point and peel,ng-o'-':.f"- of the resin layer, and pro,.,-.des a mounting mechanism which functions in the same way as the flange of the canned semiconductor laser. The flat.-esin-moulded semiconductor laser according to the present invention therefore solves the problems of' conventional. cylindrical and flat resin-moulded semiconductor lasers and is expected to widen the application targets of the resin-moulded semiconductor lasers.

Claims

CLAILMS

1. A semiconductor laser comprising: a laser diode chip, connected with a connecting means through a sub-mount layer, for emitting a laser beam; and a sealing resin layer transparent to said laser beam closely enclosing the connecting means and at least a main portion of the laser diode chip, the sealing resin layer further comprising a flat portion covering at least the main portion of said laser diode chip, the flat portion further comprising top and bottom surfaces arranged symmetrically with respect to a horizontal axis which crosses a centre of said connecting means defined by a position of said laser diode chip and side faces arranged symmetrically with respect to a vertical axis which crosses said centre of said connecting means; and at least one flange portion integrated with said flat resin portion and covering a terminal portion of said connecting means connecting thereat said connecting means with an apparatus into which said semiconductor laser is incorporated, said at least one flange portion further comprising an arcuate peripheral surface, the centre of curvature of which substantially coincides with a laser beam emitting point of said laser diode chip.

2. A semiconductor laser comprising a laser diode chip connected to one face of a generally planar connecting means through a sub-mount layer and capable of emitting a laser beam along a laser beam axis extending substantially parallel to the plane of the =onnecting means, and a sealing resin body transparent to the laser beam and closely enclosing the laser diode chip and at least a main portion of the connecting means, characterised in that the sealing resin body further comprises a substantially flat portion enclosing at least the main portion of said laser diode chip, said flat portion having generally planar parallel top and bottom surfaces parallel to and spaced substantially equidistantly from the plane of the connecting means, and side faces extending between the Cp ani bottom surfaces and spaced substantially equidiCantly from the laser beam axis; and at least one flange portion integral. with said flat portion an,,.-' spaced from the location of the laser diode chp in the d L. 1 1 i.-ectio.-. of the laser beam axis. the flange portion comprising an arcuate peripheral surface, whose centre of curvature coincides with the laser beam axis.