Optical receptacle with low transmission loss and photoelectric conversion module for the same

An optical receptacle with low transmission loss, which is connectable with an optical plug, is provided. The optical receptacle includes a photoelectric conversion module having the capability of making photoelectric conversion between light signals and electrical signals, and a module housing. The photoelectric conversion module is a molded interconnect device (MID), which is provided with a module body having a post, an optical device mounted on the post, and an electrical circuit mounted on the module body. The module housing has a tubular projection, into which an end of the optical fiber supported by the optical plug can be inserted. When the optical plug is connected with an optical receptacle, the end of the optical fiber is positioned in the tubular projection so as to be in a closely opposing relation to the optical device mounted on the post.

TECHNICAL FIELD

The present invention relates to an optical receptacle connectable with an optical plug having a light transmitting medium such as an optical fiber, and a photoelectric conversion module for the optical receptacle, which has the capability of making photoelectric conversion between light signals transmitted through the optical transmission medium and electrical signals.

BACKGROUND ART

Worldwide developments of high-speed communication system preferably used for transport means such as automobiles, airplanes, trains and shipping are now underway. For example, “MOST®” (Media Oriented System Transport) has been proposed as an optical communication standard in Europe.

FIG. 18shows a conventional optical connector designed under the “MOST®” standard (“TYCO Electronics & MOST” in Presentations by MOST members on “All Members Meeting Apr. 3, 2001”). This connector is composed of an optical receptacle1P built in an electronic equipment such as CD, DVD, GPS that can be used in the transport means, and an optical plug2P for supporting a pair of plastic optical fibers (POF)100. For example, when the optical plug2is connected to the optical receptacle1, a data communication between the electronic equipment and a data base connected through the optical fibers becomes available in the transport means.

The optical receptacle1can be mounted on a circuit board in the electronic equipment, and is mainly composed of a pair of photoelectric conversion modules10P having the capability of making photoelectric conversion between light signals transmitted through the optical fibers100and electrical signals used in the electronic equipment, a shield case50P made of a metal material for accommodating the photoelectric conversion modules, a pair of optical couplers200such as optical-fiber members having a required length, each of which is placed between an optical device of the photoelectric conversion module10P and an end of the optical fiber100supported by the optical plug2P, optical-fiber housing80for accommodating these optical couplers therein, and a receptacle housing40P for providing a space for making the connection between the optical plug2P and the optical coupler200.

One of the photoelectric conversion modules10P has the capability of converting the optical signals transmitted through the optical fiber100to the electric signals, and the other one has the capability of converting the electric signals provided from the electronic equipment to the optical signals to be supplied to the optical fiber. As shown inFIG. 19, each of the photoelectric conversion modules10P is provided with an optical device12P such as light-emitting diode and light-receiving diode, and an electric circuit14P electrically connected to the optical device by a lead wire16P. After the optical device12P and the electric circuit14P are mounted on a single lead frame90, they are integrally molded with a translucent resin11P to obtain a resin molded article95having a substantially rectangular solid shape. When the optical plug2P is connected to the optical receptacle1P, the optical signals provided from the optical fibers100of the optical plug are transmitted to the optical devices12P of the photoelectric conversion modules10P through the optical couplers200.

In addition, Japanese Patent Early Publication [kokai] No. 2001-13367 discloses an optical receptacle, as shown inFIG. 20. This optical receptacle is provided with a receptacle housing40E having a front opening41E, into which an optical plug (not shown) can be fitted, optical device modules10E, a pair of sleeves85that are useful to improve production efficiency of the optical receptacle, and a cap50E. The receptacle housing also has a rear opening43E, through which the optical device modules10E and the sleeves85are accommodated in the receptacle housing40E.

The optical device modules10E and the sleeves85are placed in the receptacle housing40E such that when the optical plug is connected to the optical receptacle1E, each of the top ends of the optical fibers supported by the optical plug is positioned in an opposing relation with the corresponding optical device module10E through the sleeve85. The sleeve85is composed of an optical waveguide portion made of glass or synthetic resin, and a cylindrical holder portion made of a metal material. Alternatively, an additional optical fiber having a required length may be used as the sleeve85.

According to this optical receptacle, since the optical device module10E is smoothly fitted in the receptacle housing40E by use of the sleeve85, it is possible to prevent the optical device module10E from being inserted in an oblique direction into the receptacle housing, and also from a breakage caused by an accidental interference with the receptacle housing. Therefore, there is an advantage that production efficiency and yield of the optical receptacle are improved, as compared with conventional cases.

However, in the conventional optical receptacles described above, since the optical couplers200such as the optical-fiber members having the required length or the sleeves85are disposed between the top ends of the optical fibers supported by the optical plug and the optical devices of the optical receptacle, an increase in transmission loss of the optical signals comes into a problem. In addition, there is another problem of increasing total component counts of the optical receptacle.

SUMMARY OF THE INVENTION

In consideration of the above-described problems, the present invention provides an optical receptacle with low transmission loss, which is connectable with an optical plug having an optical transmission medium not through an additional transmission medium such as sleeve or an additional optical fiber.

That is, the optical receptacle of the present invention comprises a photoelectric conversion module having the capability of making photoelectric conversion between light signals transmitted through the optical transmission medium and electrical signals, and a module housing for accommodating the photoelectric conversion module therein. The module housing is formed with a tubular projection, into which one end of the optical transmission medium can be inserted. The photoelectric conversion module comprises an optical device disposed in a closely opposing relation to the one end of the optical transmission medium in the tubular projection when the optical plug is connected with the optical receptacle, and an electrical circuit electrically connected to the optical device. For example, the optical device may be at least one of a light emitting element and a light receiving element.

According to the present invention, since the optical device of the optical receptacle is disposed in a closely opposing relation to the one end of the optical transmission medium supported by the optical plug in the tubular projection without using the additional optical fiber or the sleeve, it is possible to conduct optical data communications between the optical transmission medium and the optical device with a reduced transmission loss.

It is preferred that module housing has the tubular projection integrally formed on its front surface, a rear opening, through which the photoelectric conversion module is accommodated in the module housing, and a shield layer formed on its exterior surface. In this case, by the formation of the shield layer on the exterior surface of the module housing, it is possible to reduce component counts, downsize the optical receptacle as whole, and also improve resistance to noise.

It is also preferred that the photoelectric conversion module comprises a module body having a post, on a top of which the optical device is mounted, and the electric circuit is mounted on the module body. In particular, it is preferred that the post is formed in its top with a recess for mounting the optical device on a bottom of the recess, and a reflection layer for preventing a scattering of light is formed on a sidewall in the recess. In this case, since the reflection layer effectively prevents the scattering of light, it is possible to further reduce the transmission loss.

It is further preferred that the module housing has a stopper formed in the tubular projection, against which the one end of the optical transmission medium abuts when the optical plug is connected with the optical receptacle. In this case, it is possible to minimize variations in distance (gap) between the optical device and the optical transmitting medium, and stably provide a constant optical coupling efficiency therebetween.

Moreover, it is preferred that a lens is positioned between the optical device and the one end of the optical transmission medium when the optical plug is connected with the optical receptacle. In this case, the lens can improve the optical coupling efficiency therebetween. In addition, even when the distance (gap) between the optical device and the optical transmission medium accidentally increases, it is possible to minimize fluctuations of transmission loss.

In addition, it is preferred that the photoelectric conversion module is a molded interconnect device (MID) that a wiring for making electrical connection between the optical device and the electrical circuit is formed along an exterior surface of the module body. In this case, it is possible to reduce component counts, shorten assembly times, and achieve downsizing and light-weighting of the photoelectric conversion module.

As a particularly preferred embodiment of the present invention, the optical receptacle comprises a photoelectric conversion module having the capability of making photoelectric conversion between light signals transmitted through the optical transmission medium and electrical signals, and a module housing for accommodating the photoelectric conversion module therein. The photoelectric conversion module comprises a module body having a post, an optical device mounted on a top of the post, and an electrical circuit mounted on the module body and electrically connected to the optical device. The module housing has a tubular projection, into which one end of the optical transmission medium can be inserted, and a partition wall is formed in the tubular projection. The photoelectric conversion module is accommodated in the module housing such that the post is positioned at a side of said partition wall in the tubular projection. When the optical plug is connected with the optical receptacle, the one end of the optical transmission medium is positioned at the opposite side of the partition wall in the tubular projection so as to be in a closely opposing relation to the optical device mounted on the post.

According to this optical receptacle of the present invention, it is possible to provide the following advantage in addition to the above-described advantage of reducing the transmission loss. That is, when the optical plug is connected to the optical receptacle, the optical transmission medium supported by the optical plug can be inserted into the tubular projection such that the top end of the optical transmission medium abuts against the partition wall. In other words, the partition wall functions as a stopper for the optical transmission medium. Therefore, it is possible to minimize variations in distance (gap) between the optical device and the optical transmitting medium, and stably provide a constant optical coupling efficiency therebetween.

As a further preferred embodiment of the present invention, the optical receptacle comprises a receptacle housing for accommodating the module housing therein, which is used for connection with the optical plug, and has a front opening, through which the optical plug can be inserted into a plug accommodation space defined in the receptacle housing, a rear opening, through which the photoelectric conversion module is accommodated in the receptacle housing such that the tubular projection of the module housing projects in the plug accommodation space, and the rear opening is closed by an electromagnetic interference shielding member. In particular, when the photoelectric conversion module is prevented from the electromagnetic interference by the shielding member in cooperation with the above-described shield layer formed on the exterior surface of module housing, it is possible to provide excellent resistance to noise.

A further concern of the present invention is to provide a photoelectric conversion module for the optical receptacle with low transmission loss, which is connectable with an optical plug having an optical transmission medium not through an additional transmission medium. That is, the photoelectric conversion module has the capability of making photoelectric conversion between light signals transmitted through the optical transmission medium and electrical signals, and comprises a module body having a post, an optical device mounted on a top of the post, and an electrical circuit mounted on the module body and electrically connected to the optical device. The photoelectric conversion module is a molded interconnect device (MID) that a wiring for making the electrical connection between the optical device and the electrical circuit is formed along an exterior surface of said module body. The optical device mounted on the post is disposed in a closely opposing relation to one end of the optical transmission medium when the optical plug is connected with the optical receptacle.

Since the photoelectric conversion module of the present invention is the molded interconnect device (MID), which is characterized in that the electrical circuit and the optical device are mounted on the module body, e.g., a three-dimensional molded resin article, and the electric circuit is electrically connected to the optical device by the wiring pattern three-dimensionally formed along the exterior of the module body, it is possible to reduce component counts, and shorten assembly times. In-addition, by enabling higher mounting density, it is possible to achieve downsizing and light-weighting of the photoelectric conversion module, and therefore reduce size of the optical receptacle.

These and still other objects and advantages of the present invention will become more apparent from the best mode for carrying out the invention explained below, referring to the attached drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

An optical receptacle according to a preferred embodiment of the present invention is explained in detail below.

As shown inFIG. 1, the optical receptacle1of this embodiment is connectable with an optical plug2supporting one ends of a pair of plastic optical fibers (POF)110as an optical transmission medium, and preferably used for data communication between a data base connected through the other ends of the optical fibers110and an on-board electric equipment such as CD, DVD, GPS and car telephone.

As shown inFIGS. 1 and 2, the optical receptacle1is mainly composed of a pair of photoelectric conversion modules10each having the capability of making photoelectric conversion between light signals transmitted through the optical fibers100and electrical signals used in the electrical equipment, a module housing30of a resin molded article for accommodating the photoelectric conversion modules10therein, a receptacle housing40for accommodating the module housing30therein, and an electromagnetic interference shielding member50made of a metal material.

The photoelectric conversion module10can be mounted on a circuit board built in the electric equipment. One of the photoelectric conversion modules10is a first photoelectric conversion module with an optical device such as a light-receiving diode (PD), which has the capability of converting received light signals into electrical signals. The other one is a second photoelectric conversion module with another optical device such as a light-emitting diode (LED), which has the capability of converting electrical signals into light signals and projecting the light signals to the optical fiber100.

As shown inFIGS. 2 and 3, each of the photoelectric conversion modules10comprises a module body20having a column-shaped post21, the above-described optical device12attached to a top of the post, and an electrical circuit14mounted on the module body and electrically connected to the optical device. For example, the module body20may be configured in a substantially rectangular solid. The post21is integrally formed on a front surface of the module body20. The post21is formed in its top with a recess22for mounting the optical device on a bottom of the recess.

The optical device12mounted in the recess22is sealed with a translucent resin11. The translucent resin is molded in a shape of convex lens13. That is, the convex lens13for the first photoelectric conversion module is formed such that light provided from the optical fiber100is focused on a light receiving surface of the optical device12by the convex lens13. On the other hand, the convex lens13for the second photoelectric conversion module is formed such that light provided from the light-emitting diode (LED) of the optical device12is incident on the optical fiber100as parallel light beam. In particular, it is preferred that the convex lens13is formed on the optical device12by molding a translucent insulating resin at the top of the post21, and the post has an insulating protective layer19formed by coating the translucent insulating resin on a side wall of the post, at which a wiring pattern described later extends to make an electrical connection between the optical device12and the electrical circuit14.

As shown inFIG. 4, a side of the recess22is of a curved surface, on which a metal plating layer is formed as a reflection layer15for preventing a scattering of light. That is, the reflection layer15for the first photoelectric conversion module reflects the light provided from the optical fiber100, so that the reflected light is incident on the light-receiving diode (PD) of the optical device12. On the other hand, the reflection layer15for the second photoelectric conversion module reflects the light provided from the light-emitting diode (LED) of the optical device12, so that the reflected light is incident on the optical fiber100. Thus, since the reflection layer15prevents the scattering of light, it is possible to reduce coupling loss.

As shown inFIG. 5, the module body20is formed in a rear surface with a concave23for mounting the electrical circuit14on a bottom of the concave. In the case of the first photoelectric conversion module, the electrical circuit14comprises an integrated circuit, in which an input circuit for receiving output signals of the light-receiving diode (PD) is formed, and circuit components such as chip capacitors. On the other hand, in the case of the second photoelectric conversion module, the electrical circuit14comprises an integrated circuit, in which an output circuit for providing drive signals to the light-emitting diode (LED) is formed, and the circuit components such as chip capacitors.

The photoelectric conversion module10is a molded interconnect device (MID) that the wiring pattern16for making the electrical connection between the optical device12and the electrical circuit14is formed along an exterior surface of the module body20.

In this embodiment, as shown inFIG. 5, the module body20has a through hole24extending between a position adjacent to the post21on the front surface of the module body and a position close to the electrical circuit14mounted in the concave23. A metal plating layer is formed as the wiring pattern24along a side of the post21and an interior surface of the through hole24such that the optical device12mounted on the top of the post is electrically connected to the electrical circuit14. In addition, after mounting the electrical circuit14, and forming the wiring pattern24, a sealing resin25is filled in the concave23of the module body20.

As shown inFIG. 6, the module housing30is a resin molded article having a pair of tubular projections31integrally formed on its front surface, into which one end of the optical fibers100of the optical plug2can be inserted, a rear opening32, through which the photoelectric conversion modules10are accommodated in the module housing, and a shield layer33formed on its exterior surface by metal plating.

In addition, as shown inFIG. 7, the module housing30has a separation wall34therein, by which a first room used to accommodate one of the photoelectric conversion modules10therein is spaced from a second room for accommodating the other photoelectric conversion module10therein. The first and second rooms are respectively communicated with interior spaces of the tubular projections31.

In the tubular projections31, a partition wall35having a center aperture36is formed such that an optical-fiber receiving space “S2” defined at one side (right side ofFIG. 4) of the partition wall35to receive the end of the optical fiber100supported by the optical plug2is communicated with a post receiving space “S1” defined at the opposite side (left side ofFIG. 4) of the partition wall35to receive the post21of the module body20through the center aperture36.

Each of the photoelectric conversion modules10can be accommodated in the module housing30according to the following procedure. First, as shown inFIGS. 7 and 8, a plurality of L-shaped terminal pins60are attached to terminal holes26formed in the rear surface of the module body20. That is, when one end of each of the terminal pins60are pushed in the terminal hole26, the terminal pin is electrically connected to a wiring17formed on the module body20by metal plating to make an electrical connection between an interior surface in the terminal hole26and the electrical circuit14mounted on the module body20.

In this embodiment, two kinds of L-shape terminal pins (60a,60b) having long and short arms (61a,61b) are staggered in the direction of arrangement of the terminal holes26. That is, when all of the terminal pins are pushed in the terminal holes, legs (62a,62b) of the terminal pins are spaced away from each other by a distance “d1” in the transverse direction of the module body20, as shown inFIG. 9, and also each of the legs (62a,62b) are spaced away from the adjacent leg by a distance “d2” in the forward and backward direction of the module body20, as shown inFIG. 10.

After fixing the terminal pins60to the module body20, the photoelectric conversion modules10are placed in the module housing30through the rear opening32such that the post21of the module body is accommodated in the post receiving space “S1” in the tubular projection31of the module housing, and the side surface of the post21fits the interior surface of the tubular projection31, as shown inFIG. 11. At this time, a lens13is placed between the partition wall35of the module housing30and the post21having the optical device12, as shown inFIGS. 3 and 4. In other words, the top of the post abuts against a side surface of the partition wall35through the lens13, and a convex portion of the lens13projects into the center aperture36of the partition wall.

After accommodating the photoelectric conversion modules10in the module housing30, a sealing resin27is filled in the module housing, as shown inFIG. 3. InFIG. 3, the numeral28designates a locating tab formed adjacent to the post21on a front surface of the module body20. By fitting the locating tab28into a locating slot37formed in the module housing30, it is possible to accurately accommodate the photoelectric conversion module10at a desired position in the module housing30.

As shown inFIGS. 12 and 13, the receptacle housing40is a molded article of synthetic resin, which has a front opening41, through which the optical plug2can be inserted into a plug accommodation room R1defined in the receptacle housing, a rear opening43, through which the photoelectric conversion modules10are accommodated in a module accommodating room R2defined in the receptacle housing such that the tubular projections31of the module housing30projects in the plug accommodation space. R1. The rear opening43is closed by the electromagnetic interference shielding member50.

The shielding member50can be formed by punching and bending a metal sheet, which is composed of a cover plate51having a rectangular shape, a pair of claws52extending forwardly from both sides of the cover plate, three earth terminals53extending downwardly from the bottom end of the cover plate, and three contact segments54formed in the cover plate. InFIG. 13, the numeral46designates a pair of through holes formed in the receptacle housing40, into which the tubular projections31of the module housing30can be inserted, and the numeral47designates an engaging slot formed adjacent to the front opening41in the top surface of the receptacle housing.

The module housing30having the photoelectric conversion modules10therein can be accommodated in the receptacle housing40according to the following procedure. First, as shown inFIG. 14A, the module housing30is placed in the module accommodating room R2of the receptacle housing such that the tubular projections31project into the plug accommodating room R1through the through holes46of the receptacle housing40. At this time, each of the L-shaped terminal pins60supported by the module body20is fitted into a groove48formed in a bottom wall of the receptacle housing40, as shown inFIG. 14B.

Next, the shielding member50is secured to the receptacle housing40by fitting the claws52in a pair of engaging holes42formed in the top surface of the receptacle housing, as shown inFIG. 14C, while putting a pair of pins56formed on the bottom end of the cover plate51of the shielding member50in pockets49formed at the vicinity of the rear opening43of the receptacle housing40, as shown inFIG. 14D. At this time, the contact segments54of the shielding member50contact the shield layer33formed on the exterior surface of the module housing30. Therefore, when the shielding member50is connected to ground through the earth terminals53, it is possible to connect the shield layer33to the ground through the shielding member50. In addition, since each of the contact segments54is pressed against the shield layer33on the module housing30by its spring force, it is possible to achieve a reliable contact between the shielding member50and the shield layer33. Moreover, since the photoelectric conversion modules10are prevented from electromagnetic interference by the presence of the shielding member50and the shield layer33, excellent resistance to noise is obtained.

Thus, the shielding member50closes the rear opening43of the receptacle housing40to prevent a fall of the photoelectric conversion modules10from the receptacle housing, and also function as the electromagnetic interference shielding means in cooperation with the shield layer33formed on the module body30. Therefore, there are advantages of reducing total component counts of the optical receptacle1, and downsizing the optical receptacle as whole, as compared with the case of separately forming a cover for closing the rear opening of the receptacle housing and a shielding member for protecting the photoelectric conversion modules from the electromagnetic interference.

Next, the optical plug2connectable with the optical receptacle1of the present embodiment is explained. In this embodiment, shape and size of an engaging portion of the optical plug2with the optical receptacle1are determined according to the “MOST®” standard.

The optical plug2is a resin molded article, and is formed with a plug body70having a shape that can be fitted the front opening41of the receptacle housing40. The pair of optical fibers100are supported in parallel in the plug body70. The plug body has an engagement lever71on its top surface, which is used to lock or release the engagement between the optical receptacle1and the optical plug2. One end of the engagement lever71is connected to the plug body70, and a release tab72is formed at the vicinity of an opposite free end of the engagement lever. When pushing down the release tab72, the engagement lever71can be elastically deformed. The engagement lever71also has a pair of knobs73formed adjacent to the release tab72, which can be engaged in the engaging slot47of the receptacle housing40.

When the optical plug2is connected to the optical receptacle1, the top ends of the pair of optical fibers100are inserted into the optical-fiber receiving space “S2” of the tubular projections31of the module housing30. At this time, since the top end of each of the optical fibers100abuts against the side surface of the partition wall35in the tubular projection31, the partition wall can prevent the occurrence of an accidental interference between the optical fiber100and the optical device12. In addition, the partition wall functions as a stopper for inserting the optical fiber at a required depth in the tubular projection31with good repeatability. For example, when the partition wall35is not formed in the tubular projection31, the distance (gap) between the top end of the inserted optical fiber100and the optical device12fluctuates in a range of about 1.5 mm. On the other hand, when the partition wall35is formed in the tubular projection, the distance therebetween fluctuates in a smaller range of about 0.7 mm. This result suggests that the formation of the partition wall35is effective to more stably provide optical data communication with low transmission loss. Thus, the optical receptacle1having the partition wall35corresponds to one of particularly preferred embodiments of the present invention.

By the way, as described above, when the optical plug2is connected to the optical receptacle1, the top end of each of the optical fibers100abuts against the side surface of the partition wall35, and the post21of the module body20abuts against the opposite side surface of the partition wall35through the lens13. This means that the top end of the inserted optical fiber100is positioned in a closely opposing relation to the optical device12mounted on the post21in the tubular housing31. Therefore, in the present invention, since it is not necessary to arrange an additional optical fiber or an additional part such as sleeve between the optical device12and the optical fiber100supported by the optical plug2, the distance (gap) therebetween becomes smaller, so that a considerable reduction in transmission loss can be achieved.

When the optical plug2is connected to the optical receptacle1, the knobs73formed on the engagement lever71fit in the engaging slot47of the receptacle housing40to lock the connection between the optical plug and the optical receptacle. To improve easiness of locking the connection therebetween, it is preferred that each of the knobs73has a first inclined surface75for smoothly guiding the knobs into the engaging slot47, as shown inFIG. 13. On the other hand, the connection between the optical plug2and the optical receptacle1can be released by pulling out the optical plug from the plug accommodation room R1in the receptacle housing40, while pushing down the release tab72to remove the knobs73from the engaging slot47. To improve easiness of releasing the connection therebetween, it is preferred that each of the knobs73has a second inclined surface76formed at the opposite side of the first inclined surface75to smoothly guide the knobs from the engaging slot47to the outside, as shown inFIG. 12.

Next, simulation results of evaluating an influence of the presence or absence of the lens13and reflection layer15of the optical receptacle1over an amount of optical output supplied from the optical device12, i.e., the light-emitting diode (LED) to the optical fiber100are explained. That is, the simulation results ofFIG. 15were obtained by measuring relationships between an optical amount received by the optical fiber100and a distance (gap) between the light-emitting diode (LED) and the end surface of the optical fiber100under a condition that an optical output from the light-emitting diode (LED) is constant. InFIG. 15, the curve “C1” corresponds to the simulation results obtained by use of the optical receptacle1having the lens13and the reflection layer15, and the curve “C2” corresponds to the simulation results obtained by use of the optical receptacle not having the lens and the reflection layer.

In the simulation results ofFIG. 15, when the optical receptacle not having the lens and reflection layer is used, and the gap is 1 mm, the optical amount received by the optical fiber100is 1. On the other hand, when the optical receptacle having the lens13and reflection layer15is used, and the gap is 1 mm, the optical amount received by the optical fiber100is 1.8, which is much larger than the case of using the optical receptacle not having the lens and reflection layer.

Moreover, in the case of using the optical receptacle not having the lens and reflection layer, as the gap increases from 1 mm to 1.3 mm, the optical amount received by the optical fiber100reduces from 1 to 0.6. This means that the optical amount received by the optical fiber100reduces by 40% on the change in the gap. On the other hand, in the case of using the optical receptacle1having the lens13and reflection layer15, as the gap increases from 1 mm to 1.3 mm, the optical amount received by the optical fiber100reduces from 1.8 to 1.65. This means that the optical amount received by the optical fiber100reduces by only 8% on the change in the gap.

These simulation results mean that the formation of the lens13and reflection layer15is effective to minimizing the transmission loss and further increase the optical amount received by the optical fiber100. Therefore, the optical receptacle1having the lens13and the reflection layer15corresponds to one of particularly preferred embodiments of the present invention.

FIG. 16is a graph showing relationships between the transmission loss and the distance (gap) between the optical device12and the end surface of the optical fiber100. In this graph, the solid line corresponds to simulation results, and rectangular dots “□” correspond to actually measured results. The simulation results are in good agreement with the measured results.

As a modification of the above embodiment, in place of the wiring pattern16shown inFIG. 5, another wiring pattern18may be formed on the side of the post21, the front, side and rear surfaces of the module body20by metal plating, as shown inFIG. 17, to electrically connect the optical device12to the electrical circuit14mounted on the module body20without forming the through hole24in the module body.

As a further modification of the above embodiment, in place of forming the locating tab28of the module body20, the positioning of the module body in the module housing30may be performed by appropriately designing a clearance between the interior surface of the tubular projection31and the exterior surface of the post21of the module body20, or a clearance between the interior surface of the module housing30and the exterior surface of the module body20. In this case, since the module housing30not having the locating slots37is provided, it is possible to further improve the electromagnetic interference shielding effect of the module housing.

INDUSTRIAL APPLICABILITY

As understood from the above explanation, since it is not necessary to arrange an additional optical fiber or an additional part such as sleeve between the optical device and the optical fiber supported by the optical plug, the optical receptacle of the present invention can provide a low transmission loss by minimizing a distance (gap) between the top end of the optical fiber supported by the optical plug and the optical device when the optical receptacle is connected to the optical plug. In addition, since the electrical circuits such as integrated circuits and circuit components are mounted on the rear surface of the module body, and the optical device is mounted to the post formed on the front surface of the module body, there is an advantage that the optical receptacle can be readily assembled. Moreover, when the photoelectric conversion module is surrounded with the shield layer formed on the exterior surface the module body and the electromagnetic interference shielding member, it is possible to effectively prevent the photoelectric conversion module from the electromagnetic interference and provide excellent resistance to noise.

Therefore, the optical receptacle of the present invention having the capability of achieving the above-described advantages will be widely useful in the technical field of a high-speed optical communication, and preferably used for various transport means such as automobiles, airplanes, trains and shipping.