Source: http://www.google.com/patents/US4920262?dq=7751826
Timestamp: 2015-02-28 14:04:52
Document Index: 765972284

Matched Legal Cases: ['art 12', 'art 12', 'art 12', 'art 12', 'art 13', 'art 13', 'art 13']

Patent US4920262 - Photoelectric device with leads - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsIn a photoelectric device, particularly, a photoelectric device for optical communication, an optical fiber is fixed at two fixing points so that the extremity of the optical fiber is disposed opposite to the light emitting surface of a laser diode chip and the optical fiber extends in a nonlinear shape,...http://www.google.com/patents/US4920262?utm_source=gb-gplus-sharePatent US4920262 - Photoelectric device with leadsAdvanced Patent SearchPublication numberUS4920262 APublication typeGrantApplication numberUS 07/305,542Publication dateApr 24, 1990Filing dateFeb 3, 1989Priority dateMay 26, 1986Fee statusPaidAlso published asUS4803361, US4997243Publication number07305542, 305542, US 4920262 A, US 4920262A, US-A-4920262, US4920262 A, US4920262AInventorsKunio Aiki, Atsushi Sasayama, Tugio Nemoto, Makoto Haneda, Satoru Ishii, Haruo Kugimiya, Tutomu KawasakiOriginal AssigneeHitachi, Ltd., Hitachi Tobu SemiconductorExport CitationBiBTeX, EndNote, RefManPatent Citations (10), Referenced by (9), Classifications (20), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetPhotoelectric device with leads
US 4920262 AAbstract
In a photoelectric device, particularly, a photoelectric device for optical communication, an optical fiber is fixed at two fixing points so that the extremity of the optical fiber is disposed opposite to the light emitting surface of a laser diode chip and the optical fiber extends in a nonlinear shape, for example, in a moderate curve, between the two fixing points. Even though holding members fixedly holding the optical fiber at the two fixing points and a base member supporting the holding members are formed of a metal or metals having a coefficient of thermal expansion far greater than that of the optical fiber, and even if the distance between the two fixing points is varied due to the thermal expansion or contraction of the holding members and the base member, the optical fiber is obliged only to change the shape of extension. Therefore, the optical fiber and the solder fixing the optical fiber to the holding members at the two fixing points are not subjected to repeated stress, and hence the fatigue of the optical fiber and the solder is avoided. Accordingly, the photoelectric device is able to continue stable optical communication regardless of temperature variation. Terminals are formed by leads having an inductance reducing thick portion that are connected to the photoelectric device inside a box-shaped housing. A thinner lead conforming to the prevailing standard connector is connected to the thick lead using ultrasonic bonding at a position outside of the housing.
1. A photoelectric device mounted in a box shaped package comprising:a central recess formed by walls extending from a bottom wall and lid covering the recess: an optical fiber cable passing through a fiber guard in one wall into the recess; a plurality of first leads extending through the walls of said package, said first leads being aligned in a row and having a portion which is outside of said housing wall and a portion which is positioned in the recess for connection to leads on said photoelectric source by ultrasonic bonding; a plurality of second leads corresponding to said first leads, each of said second leads being connected to said portion of the corresponding first lead which is outside of said housing wall by welding; said second leads having a diameter adapted to fit into a socket and providing a first rigidity against vibration that may occur during ultrasonic bonding and at least the portions of said first leads positioned in said recess having a diameter which is greater than that of the second leads and a second rigidity against vibration that may occur during ultrasonic bonding which is greater than the first rigidity. 2. A photoelectric device as defined in claim 1 further comprising reinforcing plate means located in said recess of a plurality of said first leads and fixed to the wall being adjacent to said first leads to restrict vibration of the portion in the recess of said first lead portions in contact with said reinforcing plate.
3. A photoelectric device as defined in claim 2 wherein the reinforcing plate is made of a ceramic material having a metal plating and is soldered to a plural number of said first leads.
4. A photoelectric device as defined in claim 1 wherein said portion of the first lead which is outside of said housing wall has a diameter which is the same as that of said portion of the first lead which is positioned in the recess.
5. A photoelectric device as defined in claim 4 wherein said first lead is fixed to a wall of a hole formed in said bottom wall.
6. A photoelectric device as defined in claim 1 wherein one end of said second lead is welded at one end of said first lead.
7. A photoelectric device having two parts, one of said parts being a source of heat comprising a light emitting chip and the other part being an optical fiber mounted in a light transmitting relationship with said chip, said device including a base upon which both of said parts are mounted and a box shaped package enclosing said chip and part of said optical fiber, said device further comprising:a central recess formed by walls extending from a bottom wall and lid covering the recess: an optical fiber cable passing through a fiber guard in one wall into the recess; a plurality of first leads extending through the walls of said package, said first leads being aligned in a row and having a portion which is outside of said housing wall and a portion which is positioned in the recess for connection to leads on said photoelectric source by ultrasonic bonding; a plurality of second leads corresponding to said first leads, each of said second leads being connected to said portion of the corresponding first lead which is outside of said housing wall by welding; and means for supporting one of said parts on a member made of a conductive material including a heat insulating member positioned between said based and said member made of a conductive material, the other part being supported in a heat conducting relationship with said base. 8. The device as defined in claim 7 wherein the optical fiber is soldered to said member made of conductive material and wherein said last mentioned member serves as a means for positioning and maintaining the position of said fiber at a location to receive light emitted from said chip and be insulated from the heat generated by said chip.
9. The device as defined in claim 8 further having a wall extending from said base, a through aperture in said wall, and an optical fiber guide sleeve surrounded by a second sleeve, said second sleeve being made of heat insulation material and positioned in said aperture; andwherein said optical fiber extends through said guide sleeve. 10. The device as defined in claim 7 wherein the light emitted from said chip is laser light, the support means includes a fixing pin that extends from said base and includes said insulation member, and said optical fiber is secured at a first position to said fixing pin and at a second position remote from said chip by a support wall extending from said base.
11. The device as defined in claim 10 wherein said optical fiber has a metal coating at a position near said fixing pin and is connected to said fixing pin by solder.
12. A photoelectric device having two parts mounted in a box shaped package, one of said parts being a source of heat comprising a laser light emitting chip and the other part being an optical fiber mounted in a light transmitting relationship with said chip, said package comprising:a base upon which both of said parts are mounted; a central recess formed by walls extending from one side of said base and a lid covering said recess; a fiber guard extending through one of said walls and having a central opening through which said optical fiber passes; a fixing pin made of conductive material supported from said based and including a heat insulation portion positioned between said base and the conductive material of said pin; support means including said fixing pin for fixing and maintaining a free end of said optical fiber in a light transmitting relationship with said chip; a plurality of first leads extending through the walls of said package, said first leads being aligned in a row and having a portion which is outside of said housing wall and a portion which is positioned in the recess for connection to leads on said photoelectric source by ultrasonic bonding. Description
This is a division of application Ser. No. 054,392, filed May 26, 1987 now U.S. Pat. No. 4,803,361.
The present invention relates to a photoelectric device and, more specifically, to a photoelectric device having a package containing a laser chip which emits laser light, and an optical fiber cable which guides the laser light emitted from the laser chip outside the package.
As is described in the cited papers, to enable a semiconductor laser device to function fully and stably as a component of an optical communication equipment, it is essential to align the respective optical axes of the laser diode chip and the optical fiber at a high accuracy and to maintain the configuration of the parts, which are positioned at a high accuracy, for an extended period of time.
FIG. 1 is a plan view showing the essential portion of a photoelectric device, in a first embodiment, according to the present invention;
A photoelectric device, in a first embodiment, according to the present invention will be described with reference to FIGS. 1 through 15 as applied to an originating device incorporating a laser diode chip which emits a laser light of 1.3 or 1.5 μm in wavelength, for use in optical communication systems.
The reinforcing plate 22 is formed so as to stabilize the performance of the photoelectric device in operation in a high-frequency band. The reinforcing plate 22 is a partly metallized insulating ceramic plate. That is, nickel films 23 are formed by plating over surface of areas where the reinforcing plate 22 contacts the leads 6, respectively. The leads 6 are fixed firmly to the nickel films 23 by silver solder 24. Accordingly, the leads 6 are restrained from vibration during the ultrasonic bonding process. Furthermore, since the nickel films 23 are formed in a fixed width, area through which electric current flows is increased, so that the parasitic inductance of the leads 6 is reduced to enable stable optical communication in a high-frequency band as high as 565Mbit/sec. For example, the parasitic inductance on the order of 6 nH of a lead of 0.45 mm in diameter and 7 mm in length is reduced to 3 nH by providing gold films 23 of a fixed width over the areas where the reinforcing plate 22 contacts the leads 6.
The base plate 9 is fixed to the inner surface of the bottom wall of the package body 7 at a position near the wall to which the flange 3 is attached with a brazing filler material. The Peltier element 10 is fixed to the upper surface of the base plate 9, and hence it is desirable to form the base plate 9 of a material having a high thermal conductivity. The upper and lower electrode plates 27 of the Peltier element 10 are formed of an alumina ceramic having a coefficient of thermal expansion on the order of 6.7�10-6 /� C. Therefore, if the base plate 9 is formed of copper having a high thermal conductivity and a coefficient of thermal expansion of 17.0�10-6 /� C., the solder joining the electrode plate 27 to the base plate 9 will be caused to break by fatigue due to the difference between the electrode plate 27 and the base plate 9 in thermal expansion. Accordingly, to avoid the breakage of the solder, the base plate 9 is formed, for example, of a copper/tungsten (Cu/W) alloy having a coefficient of thermal expansion in the range of 6.0 to 7.0�10-6 /� C. and a thermal conductivity in the range of 0.5 to 0.67 cal/cm�sec�� C. One side of the base plate 9 is in contact with the wall of the package body 7 to transfer heat from the base plate 9 through the wall of the package body 7 to the flange 3. The coefficient of thermal expansion of covar forming the bottom wall of the package body 7 is 5.3�10-6 /� C. The base plate 9 may be formed of SiC or the like.
A submount 32 is attached fixedly by a fluxless low temperature melting-solder such as, for example, a Pb/Sn/In solder, to the holding part 12 at a position on the prolongation of the adjusting section 28 of the positioning and fixing member 17. The submount 32 is formed of an insulating SiC having a high thermal conductivity and a coefficient α of thermal expansion of 3.7�10-6 /� C. which is approximate to those of Si and a compound semiconductor. As shown in FIG. 8, the main surface of the submount 32 is metallized to form a metal layer 33. Au/Sn eutectic layers 34 and 35 are formed on the metal layer 33, and the laser diode chip 15 and a gold pedestal 36 are attached fixedly to the upper Au/Sn eutectic layers 34 and 35, respectively. The eutectic layers 34 and 35 may be substituted by a Pb layers or Pb/Sn layers. Thus, the lower electrode of the laser diode chip 15 is connected electrically through the metal layer 33 to the pedestal 36 and as shown in FIG. 8, is fixed to the submount 32 with the resonator 38 which emits a laser light 37 positioned apart from the submount 32, namely, with the P-surface of the pn laser diode facing up. The upper electrode of the laser diode chip 15 is connected electrically to the holding part 12 by two wires 20, while the pedestal 36 is connected electrically to the leads 6 by two wires 20 as shown in FIGS. 1 and 2. Such a manner of electrical connection of the laser diode chip 15 and the holding part 12 and that of the pedestal 36 and the leads 6 are necessary to change the polarity to use the driving side of the laser diode chip 15 in driving the same by a fast transistor. The laser diode chip 15 is mounted on the submount 32, and then the submount 32 is fixed to the holding part 12.
Since the laser diode chip 15 and the positioning and fixing member 17 for positioning the optical fiber 16 are dislocated from the center axis of the heat sink 14, the positioning and fixing member 17 is not located on the prolongation of the fiber guide 4 of the package body assembly. Accordingly, when the optical fiber 16 is extended slack between the fiber guide 4 and the positioning and fixing member 17, the optical fiber 16 extends in a curve as shown in FIGS. 2 and 13. When the optical fiber 16 is thus extended slack between the two fixing points, the optical fiber 16 is not exposed to an excessive force even when the distance between the two fixing points varies due to temperature variation, and hence the communication is carried out without any interference. If the optical fiber 16 is extended taut in a straight line between the two fixing points, the relative position of the two fixing points varies due to the thermal expansion or thermal contraction of the associated parts exerting excessive force to or breaking the optical fiber 16. When the optical fiber 16 is extended slack in a curve between the two fixing points, the optical fiber 16 bends in a curve as indicated by an alternate long and short dash line or as indicated by an alternate long and two short dashes line in FIG. 13 when one of the fixing points is shifted relative to the other from a point A where the fixing point is located at a normal temperature to a position B at a high temperature or to a point C at a low temperature, respectively, so that the optical fiber 16 is not exposed to excessive force and hence the optical fiber 16 is not damaged. The inclination θ of center axis of the positioning and fixing member 17 to the center axis of the heat sink 14 is determined so that the optical fiber 16 extending between the fiber guide 4 and the positioning and fixing member 17 is able to bend moderately and will not be deformed excessively to an extent liable to cause trouble with optical communication. If the inclination θ is excessively large, the length of the optical fiber 16 between the two fixing positions become excessively large making the assembling work difficult. In this embodiment, the inclination θ is ten degrees.
A chip carrier 39 mounted with the light receiving element 18 is attached fixedly through an Au/Sn eutectic layer to the main surface of the heat sink 14. The chip carrier 39 is a ceramic block. Metal layers 40 and 41 are formed by metallizing over the main surface, namely, one side surface, and the upper surface of the chip carrier 39, respectively. The light receiving element 18 is attached fixedly through an Au/Sn eutectic layer to the metal layer 40. The upper electrode of the light receiving element 18 is connected electrically to the metal layer 41 by a wire 42. Since the rectangular chip carrier 39 is fixed to the heat sink 14 so that one side thereof conincides with one side of the heat sink 14, the light receiving surface of the light receiving element 18 is inclined to the laser light 37. Accordingly, the laser light is not reflected by the light receiving surface of the light receiving element 18 toward the light emitting surface of the laser diode chip 15, so that the generation of noises attributable to the reflected laser light is obviated.
It is one of the features of the present invention to extend the tubular positioning and fixing member 17 capable of plastic deformation through and to fix the same to the supporting part 13. The positioning and fixing member 17 serves as means for holding and positioning the optical fiber 16. Accordingly, the positioning and fixing member 17 is formed of a material capable of easy plastic deformation such as, for example, a cupronickel, and has the deformable adjusting section 28 having a smaller diameter and penetrating the supporting part 13, and a guide section 29 having a larger diameter and having the shoulder in abutment with the outer side of the supporting part 13. The free end of the optical fiber 16 is passed through the positioning and fixing member 17 and is fixed to the extremity cut aslant of the adjusting section 28 by the solder 30. The extremity of the free end of the optical fiber 16 held fixedly by the adjusting section 28 is located opposite to one of the light emitting surfaces of the laser diode chip 15. Since the adjusting section 28 of the positioning and fixing member 17 is formed of a material capable of plastic deformation in an elongate shape, the adjusting section 28 can be easily and correctly bent for the positional adjustment of the extremity of the adjusting section 28 when a force is applied in parallel to a plane perpendicular to the axis of the adjusting section 28 by means of the position adjusting bar 46 or a suitable tool. Consequently, as shown in FIG. 15, the positional adjustment of the extremity of the optical fiber 16 held by the adjusting section 28 is achieved to bring the optical axis of the optical fiber 16 into highly accurate alignment with that of the laser diode chip 15.
(2) Since the optical fiber is not exposed to any excessive stress as mentioned in paragraph (1), above the solder fixing the optical fiber will not be caused to fracture due to fatigue, so that the high efficiency of optical connection of the laser diode chip and the optical fiber as adjusted is maintained.
(5) The subcarrier is formed by incorporating the laser diode chip, the light receiving element, the thermistor, and the positioning and fixing member for positioning and fixedly holding the optical fiber into the heat sink, as mentioned in article (4). Accordingly, the assembly of the essential components of the photoelectric device is achieved by fixing the subcarrier to the Peltier element fixed to the package body subassembly, and aligning the optical axis of the optical fiber fixedly held by the positioning and fixing member of the subcarrier with that of the laser diode chip, which enables accurate assembly of the photoelectric device.
The submount 108 fixedly holding the laser diode chip 109 (semiconductor laser element) is secured to the rectangular pedestal 107 formed at the center of the recess of the stem 102. As shown in FIG. 22, the submount 108 is fixed to the pedestal 107 of the stem 102 by a bonding material 110, while the laser diode chip 109 is fixed to the submount 108 by a bonding material 111. The tubular fiber guide 112 penetrates one of the side walls of the stem 102 and is secured hermetically to the stem 102 by the heat insulating member 113 formed of a heat insulating material such as, for example, covar glass having a thermal conductivity on the order of 0.04 cal/cm�sec�� C. The fiber guide 112 receives the free end of the optical fiber cable 104 therethrough. A portion of the jacket covering the free end of the optical fiber cable 104 is removed to expose the optical fiber 114 consisting of a core and a cladding. The outer end of the fiber guide 112 is caulked to hold the optical fiber cable 104 securely. The circumference of the optical fiber 114 is metallized to enable soldering the optical fiber 114 to the fiber guide 112 by solder 115.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4233619 *Oct 30, 1978Nov 11, 1980Rca CorporationLight detector housing for fiber optic applicationsUS4296998 *Dec 17, 1979Oct 27, 1981Bell Telephone Laboratories, IncorporatedEncapsulated light source with coupled fiberguideUS4439006 *May 18, 1981Mar 27, 1984Motorola, Inc.For coupling an optical fiber transmission lineUS4440470 *Aug 17, 1981Apr 3, 1984U.S. Philips CorporationOptical transmission system coupling a semiconductor laser diode to a multimode optical fiberUS4523802 *Feb 8, 1982Jun 18, 1985Kokusai Denshin Denwa Kabushiki KaishaUnitary mounting structure for semiconductor laser and optical fiberUS4623220 *Jul 2, 1984Nov 18, 1986Amp IncorporatedLaser to fiber connectionUS4627687 *Feb 27, 1984Dec 9, 1986International Standard Electric CorporationDevice for holding in position a transducer and an optical waveguideUS4702556 *Aug 22, 1984Oct 27, 1987Hitachi, Ltd.Method of assembling a light emitting device with an optical fiberUS4707067 *Feb 22, 1985Nov 17, 1987Siemens AktiengesellschaftOpto-electronic module housingUS4807956 *Oct 16, 1987Feb 28, 1989Thomson Hybrides Et MicroondesOpto-electronic head for the coupling of a semi-conductor device with an optic fiber, and a method to align this semi-conductor device with this fiber* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS4993803 *May 7, 1990Feb 19, 1991General Motors CorporationElectro-optical header connectorUS4997243 *Mar 8, 1990Mar 5, 1991Hitachi, Ltd.Method of mounting a light emitting chip and an optical fiber on a photoelectric deviceUS5113466 *Apr 25, 1991May 12, 1992At&T Bell LaboratoriesMolded optical packaging arrangementUS5123066 *Apr 25, 1991Jun 16, 1992At&T Bell LaboratoriesMolded optical package utilizing leadframe technologyUS5522225 *Dec 19, 1994Jun 4, 1996Xerox CorporationThermoelectric cooler and temperature sensor subassembly with improved temperature controlUS5606182 *Apr 25, 1995Feb 25, 1997Mitsubishi Denki Kabushiki KaishaOptical semiconductor device for optical communications with increased positional accuracy of an optical access and method of fabricating the sameUS5960142 *Aug 12, 1997Sep 28, 1999Nec CorporationPeltier cooler and semiconductor laser module using Peltier coolerUS6075914 *Apr 9, 1998Jun 13, 2000Bookham Technology LimitedApparatus for connecting an optical fiber to an optical deviceUS7070340 *Feb 14, 2002Jul 4, 2006Silicon Bandwidth Inc.High performance optoelectronic packaging assembly* Cited by examinerClassifications U.S. Classification250/227.11, 385/53International ClassificationH01S5/022, G02B6/42, H01S5/024Cooperative ClassificationH01L2224/73265, H01L2224/48091, H01S5/02268, G02B6/4236, G02B6/4202, G02B6/4238, H01S5/02415, H01S5/02284, G02B6/4204, H01S5/02438European ClassificationH01S5/024A2, H01S5/022W2, G02B6/42C5V, G02B6/42C3, G02B6/42C2Legal EventsDateCodeEventDescriptionSep 10, 2003ASAssignmentOwner name: EASTERN JAPAN SEMICONDUCTOR TECHNOLOGIES, INC., JAFree format text: MERGER;ASSIGNOR:HITACHI TOBU SEMICONDUCTOR, LTD.;REEL/FRAME:014484/0709Effective date: 20021001Owner name: RENESAS EASTERN JAPAN SEMICONDUCTOR, INC., JAPANFree format text: CHANGE OF NAME;ASSIGNOR:EASTERN JAPAN SEMICONDUCTOR TECHNOLOGIES, INC.;REEL/FRAME:014484/0721Effective date: 20030401Owner name: EASTERN JAPAN SEMICONDUCTOR TECHNOLOGIES, INC. 1-1Owner name: RENESAS EASTERN JAPAN SEMICONDUCTOR, INC. 3-2, FUJSep 3, 2003ASAssignmentOwner name: OPNEXT JAPAN, INC., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HITACHI, LTD.;RENESAS EASTERN JAPAN SEMICONDUCTOR, INC.;REEL/FRAME:014468/0991Effective date: 20030901Owner name: OPNEXT JAPAN, INC. 216 TOTSUKACHO, TOTSUKA-KU, YOKSep 26, 2001FPAYFee paymentYear of fee payment: 12Sep 26, 1997FPAYFee paymentYear of fee payment: 8Sep 30, 1993FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services