Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Patent
1997-09-29
1999-08-10
Tran, Minh Loan
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
257 99, 257432, 257433, 385 92, H01L 3300, H01L 310232, H01L 310203
Patent
active
059362634
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates generally to an optical module and a method of manufacturing the same, and more specifically to an optical module having a receptacle formed as an integrally formed metallic tubular piece, into which a ferrule of an optical plug being connected is inserted, a high hardness film of TiC having a hardness of 2800-3500 Hv (Vickers hardness) formed at least on the inner circumferential surface of the bore of the receptacle, and a method of manufacturing the same. This technology is useful as a light emitting or receiving device used in an optical LAN, for example.
BACKGROUND ART
An optical module is an optical component for optically coupling a semiconductor light-emitting element or semiconductor light-receiving element to an optical fiber. It is being widely used in optical communications and many other fields. In a computer system used for data communications, for example, a semiconductor light-emitting element module and a semiconductor light-receiving element module are mounted as a pair on a board. Optical modules of this type usually comprises an optical semiconductor element (a semiconductor light-emitting element such as a laser diode, or a semiconductor light-receiving element such as a photodiode, for example), a holder for holding the optical semiconductor element, and a receptacle core fixed to the holder for holding a ferrule of an optical plug being connected in a fixedly fitted manner, the optical semiconductor element being optically connected with the optical fiber in the ferrule when the optical plug is connected to the optical module.
The ferrule of the optical plug is a member for holding an end of the optical fiber along the central axis thereof. It is made of stainless steel in some cases, but more commonly made of a ceramic material such as zirconia, due to durability and reliability. The receptacle core, on the other hand, is required to have even better wear resistance since it is a member into and from which the ferrule is frequently inserted or detached when connecting and disconnecting the optical plug, and because the optical module is a component which is mounted on a board. In the prior art, therefore, a construction has often been adopted in which a ceramic sleeve made of a ceramic material such as zirconia, is press-fitted or adhered to the inner circumferential surface of a tubular core housing.
When a ceramic sleeve made of zirconia, which has a relatively high hardness and good wear resistance, is used as the receptacle core of an optical module, these ceramic components have to be machined into precise dimensions and press-fitted to a core housing. Thus, the ceramic sleeve tends to be extremely expensive. A construction in which a split sleeve made of phosphor bronze is inserted into the core housing may be adopted to achieve low-cost manufacture. Metallic sleeves, however, generally have poor wear resistance, compared with ceramic sleeves, and lack reliability and durability because they are apt to wear compared with ceramic ferrules. Furthermore, repeated attaching and detaching may cause the problem of changes in the amount of light coupled between the optical semiconductor element and the optical fiber.
As a method for solving this problem, an optical connector receptacle has been proposed in which the contact surface (the inner circumferential surface of the bore) of the receptacle core with which the ferrule makes contact is covered with a material having such a low friction coefficient that the dynamic friction coefficient thereof with the ferrule becomes less than 0.7 (Japanese Patent Publication No. 3-107807). In the disclosure, materials selected from a group consisting of TiN, zirconia, alumina, polytetrafluoroethylene, fluorine resin and MOS.sub.2, or a composite material containing such materials are cited as examples of coating materials having low friction coefficient. This technique is based on the concept that the use of a receptacle core whose contact surface with the ferrule has a low friction coefficient
Nippatsu Hanbai Kabushiki Kaisha
Nippon Sheet Glass Co. Ltd.
Tran Minh Loan
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