Optical connector

To provide an optical connector which enables suppression of crosstalk, an optical connector includes a housing, an optic transceiver and a lens body, wherein the lens body includes a light emitting side lens section configured to be interposed between a light emitting element and one optical fiber of a partner optical connector, a light receiving side lens section configured to be interposed between a light receiving element and another optical fiber of the partner optical connector, and a light receiving side lens surrounding section in an integrated manner. A light shield section is formed in the lens body, the light shield section being configured to suppress a portion of light emitted from the light emitting element which enters the light receiving element via the lens body. The light receiving side lens surrounding section is configured to be transparent at an end facing the partner optical connector.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to an optical connector with an optic transceiver (FOT: Fiber Optic Transceiver) and a lens body.

Background Art

Conventionally, a board and an optical fiber are connected via a pair of optical connectors e.g. in an automobile LAN. One of the pair of optical connectors which is a “board side optical connector” includes an optic transceiver connected to a board, a light guide element with a lens function (hereinafter referred to as a “lens body”), a housing accommodating them etc. The other of the optical connectors which is an “optical fiber side optical connector” includes ferrules, a housing accommodating the ferrules etc., the ferrules being attached to respective ends of two optical fibers for transmission and receiving.

A mating space for receiving the optical fiber side optical connector is formed in the housing for the board side optical connector. By mating the optical fiber side optical connector with the mating space, end faces of the optical fibers are oriented toward the lens body. Then, light is transferred from one optical fiber through the lens body to a light receiving element of the optic transceiver, and transferred from a light emitting element of the optic transceiver through the lens body to the other optical fiber (see e.g. Patent Document 1).

CITATION LIST

Patent Literature

Patent Document 1: JP 2019-56895 A

SUMMARY OF THE INVENTION

According to Patent Document 1 as mentioned above, there is the problem that “crosstalk” may occur in the board side optical connector in which a portion of light emitted from the light emitting element enters the light receiving element via the lens body. When the crosstalk occurs, it is not possible to transmit and/or receive a correct signal, which is undesirable.

In order to solve the above-mentioned problem, an objective of the present invention is to provide an optical connector which enables suppression of crosstalk.

An optical connector according to the present invention includes a housing, an optic transceiver with a light emitting element and a light receiving element, the optic transceiver being accommodated in the housing, and a lens body accommodated in the housing, the lens body being configured to be interposed between a partner optical connector and the optic transceiver, wherein the lens body includes a light emitting side lens section configured to be interposed between the light emitting element and one optical fiber of the partner optical connector, a light receiving side lens section configured to be interposed between the light receiving element and another optical fiber of the partner optical connector, and a light receiving side lens surrounding section with a tubular shape in an integrated manner, the light receiving side lens surrounding section surrounding the light receiving side lens section, in an integrated manner, wherein a light shield section is formed in a section of the lens body which connects the light emitting side lens section to the light receiving side lens section, and wherein an end of the light receiving side lens surrounding section facing the partner optical connector is configured to be transparent.

Since the light shield section according to the present invention is formed in the section of the lens body connecting the light emitting side lens section to the light receiving side lens section, it is possible to suppress a portion of light emitted from the light emitting element which enters the light receiving element via the lens body (crosstalk).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An “optical connector” according to an embodiment of the present invention will be described with reference toFIGS. 1 to 6.

Optical connectors1as shown inFIG. 1are configured to be mounted on a board. The optical connectors1are configured to be mated with partner optical connectors2which are connected to terminal ends of optical fibers11. In the shown example, the partner optical connectors2are connected to both opposite terminal ends of two optical fibers11, each of the partner optical connectors2being mated with one of the optical connectors1.

As shown inFIG. 3, the partner optical connectors2include ferrules7having a cylindrical shape, housings8made of resin which accommodates the ferrules7, and holders9incorporated into the housing8, the ferrules7being attached to respective ends of two optical fibers11for transmission and receiving, and the holder9being configured to prevent the ferrules7from removal.

Each of the two optical fibers11is formed from a bare fiber12and a coating13covering the bare fiber12, wherein the bare fiber12is formed from a core and a cladding. Each of the optical fibers11is inserted into the ferrules7, with the coating13being removed at the end of the optical fiber11.

As shown inFIG. 2, each of the optical connectors1includes a housing3made of resin, a shield case6, an optic transceiver (FOT: Fiber Optic Transceiver)4accommodated into the housing3, and a lens body5accommodated into the housing3, wherein the lens body5is configured to be interposed between the partner optical connector2and the optic transceiver4.

The housing3includes an outer wall section30with a quadrilateral-tubular shape and a pair of tubular sections31arranged in an inside space of the outer wall section30in an integrated manner. As shown inFIG. 4, the tubular sections31in the inside space of the outer wall section30accommodate the lens body5and the optic transceiver4on their one side. Further, the partner optical connector2is mated with the tubular sections31in the inside space of the outer wall section30on their other side. The space on the other side shall be referred to as a “mating space34”.

As shown inFIG. 4, the tubular sections31serve for receiving and positioning the optical fibers11and ferrules7of the partner optical connector2. The tubular sections31are formed in a cylindrical shape corresponding to a tip shape of the ferrules7. The pair of tubular sections31are arranged in a series in a width direction of the housing3. A central axis of each of the tubular sections31extends in parallel to a central axis of the outer wall section30(i.e. a mating direction of the partner optical connector2).

The shield case6is obtained by applying e.g. a pressing process to a metal sheet. As indicated inFIG. 2, the shield case6includes an upper surface section61covering an upper surface of the outer wall section30, a pair of side surface sections62covering both side surfaces of the outer wall section30, a back surface section63covering the optic transceiver4, and board connecting sections64extending from the respective side surface sections62.

As shown inFIGS. 2 and 4, the optic transceiver4includes a light emitting element (a light emitting diode, a laser diode etc.)41, a light receiving element (photodiode etc.)42, a plurality of leads44to be connected to the board, and a holder40made of resin which holds them. A pair of locking projections43are formed at opposite ends of the holder40, the locking projections43being configured to engage with the lens body5.

As shown inFIGS. 4 and 5, the lens body5includes a light emitting side lens section51configured to be interposed between the light emitting element41and one optical fiber11, a light receiving side lens section52configured to be interposed between the light receiving element42and the other optical fiber11, a light emitting side lens surrounding section54, a light receiving side lens surrounding section55, a plate section50integrated therewith, and a pair of locking arms53extending from both opposite ends of the plate section50, in an integrated manner.

The light emitting side lens section51and light receiving side lens section52are configured as biconvex lenses which have convex surfaces on both sides. In the present example, the light receiving side lens section52is formed with a larger thickness than the light emitting side lens section51. The light emitting side lens section51and light receiving side lens section52are formed in a circular shape when seen in their axial direction. The light emitting side lens section51and light receiving side lens section52have a larger diameter than the bare fibers12of the optical fibers11.

The light emitting side lens surrounding section54is formed in a cylindrical shape and surrounds the light emitting side lens section51. An outer circumference of the light emitting side lens section51is connected to an inner circumference of the light emitting side lens surrounding section54. An end face of the light emitting side lens surrounding section54facing the partner optical connector2is located closer to the partner optical connector2than a central portion (a furthest projecting portion) of an optical fiber opposing surface51aof the light emitting side lens section51.

The light receiving side lens surrounding section55is formed in a cylindrical shape and surrounds the light receiving side lens section52. An outer circumference of the light receiving side lens section52is connected to an inner circumference of the light receiving side lens surrounding section55. An end face of the light receiving side lens surrounding section55facing the partner optical connector2is located closer to the partner optical connector2than a central portion (a furthest projecting portion) of an optical fiber opposing surface52aof the light receiving side lens section52. A location at which the light receiving side lens surrounding section55intersects an outer edge of the optical fiber opposing surface52aof the light receiving side lens section52shall be referred to as an “intersection portion”, and is designated with the reference sign55c.

The plate section50is formed in a rectangular-plate shape when seen in the axial direction of the light emitting side lens section51and light receiving side lens section52. The plate section50is connected to the outer circumferences of the light emitting side lens surrounding section54and light receiving side lens surrounding section55.

The pair of locking arms53is engaged with the pair of locking projections43of the optic transceiver4, as shown inFIG. 4. The optic transceiver4and the lens body5are assembled with each other by engaging the locking projections43with the locking arms53, wherein they are incorporated into the housing3in such an assembled state with each other. Then, the shield case6is incorporated into the housing3.

As indicated inFIG. 4, in a state where the lens body5is incorporated into the housing3, the light emitting side lens section51and the light emitting side lens surrounding section54are partially located in one of the tubular sections31, while the light receiving side lens section52and the light receiving side lens surrounding section55are substantially located in the other of the tubular sections31.

The above-mentioned lens body5is obtained by means of two-component molding with a transparent resin and a black resin. In the present example, the light emitting side lens section51, the light receiving side lens section52, an end55bof the light receiving side lens surrounding section55facing the partner optical connector2, both opposite ends50aand50bof the plate section50, and the pair of locking arms53are formed from transparent resin. In more details with regard to the extension of the “end55b” of the light receiving side lens surrounding section55, it extends from a portion of the light receiving side lens surrounding section55which is slightly closer to the optic transceiver4than the intersection portion55c, to the end face of the light receiving side lens surrounding section55facing the partner optical connector2. And the remaining portions, i.e. the light emitting side lens surrounding section54, a portion55aof the light receiving side lens surrounding section55facing the optic transceiver4, and a central portion50cof the plate section50are formed from the black resin. These portions formed from the black resin shall be referred to as “light shield section”, and is designated with the reference sign56.

Since the above-mentioned light shield section56includes a portion of the lens body5which connects the light emitting side lens section51to the light receiving side lens section52, it is possible to suppress a portion of light emitted from the light emitting element41which enters the light receiving element42via the lens body5(crosstalk).

Although in the present example the light shield section56is formed with black resin, it is to be noted that it is sufficient to form the light shield section56according to the present invention with a material having a low transmission for a used wavelength. Further, the light shield section56according to the present example is formed widely extending to the periphery around the light emitting side lens section51and the light receiving side lens section52, beyond the portion of the lens body5which connects the light emitting side lens section51to the light receiving side lens section52(a portion between the light emitting side lens section51and the light emitting side lens section52), in order to prevent crosstalk with more reliability. However, it is sufficient according to the present invention to form the light shield section at least at a portion connecting the light emitting side lens section51to the light receiving side lens section52. Furthermore, in the present example, both opposite ends50aand50bof the plate section50as well as the pair of locking arms53are formed from transparent resin. However, these portions may be formed from black resin.

The end55bof the light receiving side lens surrounding section55is formed from transparent resin from the following reasons: an axis offset may occur in the optical connectors1between an optical fiber11of the partner optical connector2and the light receiving side lens section52as shown inFIG. 6, e.g. due to backlash in mating with the partner optical connector2and/or backlash of an assembled component. In this case, a portion of light emitted from the optical fiber11leaks from the optical fiber opposing surface52aof the light receiving side lens section52, and then falls on the end55bof the light receiving side lens surrounding section55. If this end55bwere made of black resin, it would absorb the fallen light, which might reduce the communication reliability between the optical connectors1and2.

With regard to this matter, the end55baccording to the present example is configured to be transparent, which enables that the leakage light from the optical fiber opposing surface52adue to the above-mentioned axis offset is reflected at the end55bto enter the optical fiber opposing surface52aas shown inFIG. 6. Accordingly, it is possible to suppress the reduction of the communication reliability between the optical connectors1and2.

In this manner, the optical connectors1according to the present example can suppress “crosstalk” in which a portion of light emitted from the light emitting element41enters the light receiving element42via the lens body5, while suppressing light loss even when the axis offset occurs between the optical fibers11of the partner optical connectors2and the light receiving side lens section52, which can suppress reduction of the communication reliability with the partner connectors2.

It is to be noted that the embodiments as described above merely illustrate representative examples for the present invention, and the present invention is not limited to these embodiments. I.e., various modifications may be performed without departing from the core of the present invention. It is obvious that such modifications are included in the scope of the present invention as far as the modifications comprise the features of the present invention.

REFERENCE SIGNS LIST