Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
1999-06-08
2001-01-09
Lee, John D. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S088000
Reexamination Certificate
active
06170996
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical module and a manufacturing method therefor.
2. Description of the Related Art
In recent years, the development of an optical access network has been actively carried out. For realization of the optical access network, reducing the cost of an optical device and/or an optical module is a very important subject. Further, in encapsulating an optical element for making conversion from light to electricity or conversion from electricity to light, a further cost reduction is necessary, and it is required to realize an optical module which can simply encapsulate the optical element and can ensure a sufficient reliability.
In many optical modules at present, a metal package or a ceramic package is used to ensure reliability, and the package is hermetically sealed by welding or soldering, so that the cost of each optical module becomes very high. It is therefore an important subject for the cost reduction of an optical module to simplify an encapsulation method for an optical element. As an example of a method of simply hermetically sealing an optical module, there has been proposed a method including the steps of applying a resin to the entire surface of a substrate on which an optical element is mounted, and next curing the resin to hermetically seal the optical element (Mitsuo Fukuda et al., “Plastic Packaging of Semiconductor Laser Diode”, Electronic Components and Conference, 1996, pp 1101-1108).
An optical module such as a light emitting module or a photodetecting module is required to be connected to an optical connector, so as to launch an optical signal to an optical fiber transmission line or to receive an optical signal from an optical fiber transmission line, and it is accordingly necessary to realize an optical module allowing the connection to the optical connector with a simple structure. However, in the case that a resin is applied to the entire surface of a substrate on which an optical element is mounted, and the resin is next cured to hermetically seal the optical element as described in the above literature, there is a possibility of separation of the resin from the substrate or generation of cracks or the like in the resin due to a difference in coefficient of linear expansion between the substrate and the resin. Furthermore, the substrate may be broken by a residual stress in the resin.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a low-cost, high-reliability optical module which can be easily connected to an optical fiber transmission line.
It is another object of the present invention to provide a manufacturing method for a low-cost, high-reliability optical module.
In accordance with an aspect of the present invention, there is provided an optical module comprising a plurality of leads; a substrate having a plurality of conductive patterns electrically connected to the leads; an optical element mounted on the substrate for making conversion between light and electricity; a first resin for encapsulating the optical element, the first resin having transparency to the light; and a second resin for enclosing all of the leads, the substrate, the optical element, and the first resin except a part of each of the leads; the second resin being formed with a hole for receiving a ferrule, so as to optically couple an optical fiber inserted in the ferrule through the first resin to the optical element, the hole being closed by the first resin.
In accordance with another aspect of the present invention, there is provided an optical module comprising a plurality of leads; a substrate having a plurality of conductive patterns electrically connected to the leads; an optical element mounted on the substrate for making conversion between light and electricity; and a resin for enclosing the leads, the substrate, and the optical element except a part of each of the leads, the resin having transparency to the light; the resin being formed with a hole for receiving a ferrule, so as to optically couple an optical fiber inserted in the ferrule through the resin to the optical element.
In the optical module according to the present invention, all the components including the substrate are sealed with the molded resin, so that separation of the molded resin from the substrate can be prevented, and generation of cracks or the like in the molded resin can also be prevented, thereby ensuring the cost reduction and reliability of the optical module.
In accordance with a further aspect of the present invention, there is provided a manufacturing method for an optical module, comprising the steps of providing a lead frame having a plurality of leads; mounting a substrate having a plurality of conductive patterns on the lead frame; mounting an optical element for making conversion between light and electricity on the substrate; placing a sleeve having a front end on the substrate so that the front end is adjacent to the optical element; inserting a core having a front end into the sleeve until the front end of the core comes to the front end of the sleeve; applying a first resin in a liquid state to the optical element so as to fully cover the optical element, the first resin having transparency to the light; curing the first resin to encapsulate the optical element and close the front end of the sleeve; connecting the conductive patterns through a plurality of wires to the leads, respectively; providing a mold enclosing all of the substrate, the optical element, the sleeve, the first resin cured, the wires, and the lead frame except a part of the sleeve and a part of each of the leads; injecting a second resin in a liquid state into the mold to fill the mold with the second resin; curing the second resin; and removing the mold from the second resin cured and drawing the core out of the sleeve.
In accordance with a still further aspect of the present invention, there is provided a manufacturing method for an optical module, comprising the steps of providing a lead frame having a plurality of leads; mounting a substrate having a plurality of conductive patterns on the lead frame; mounting an optical element for making conversion between light and electricity on the substrate; placing a core having a front end on the substrate so that the front end of the core is adjacent to the optical element; applying a first resin in a liquid state to the optical element so as to fully cover the optical element, the first resin having transparency to the light; curing the first resin to encapsulate the optical element; connecting the conductive patterns through a plurality of wires to the leads, respectively; providing a mold enclosing all of the substrate, the optical element, the first resin cured, the wires, and the lead frame except a part of the core and a part of each of the leads; injecting a second resin in a liquid state into the mold to fill the mold with the second resin; curing the second resin; and removing the mold and the core from the second resin cured.
As a modification, a package having an upper opening may be used in place of the mold. In this case, the second resin is poured into the package from the upper opening, and is next cured to be integrated with the package, thereby eliminating the need for the step of removing the mold from the second resin cured.
The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.
REFERENCES:
patent: 5414293 (1995-05-01), Broom
patent: 5960141 (1999-09-01), Sasaki et al.
patent: 6019523 (2000-02-01), Honmou
patent: 6075911 (2000-06-01), Goto
patent: 63-5310 (1988-01-01), None
patent: 5-245853 (1993-09-01), None
patent: 5-243445 (1993-09-01), None
patent: 5-243444 (1993-09-01), None
patent: 6-069604 (1994-03-01), None
patent: 8-122588 (19
Miura Kazunori
Sasaki Seimi
Yamamoto Naoki
Connelly-Cushwa Michelle R.
Fujitsu Limited
Lee John D.
Staas & Halsey , LLP
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