Optical fiber end-surface polishing device

Abstract: An optical fiber end-surface polishing device has an improved ferrule fixing device allowing ferrules (15) with optical fibers (14) to be attached to or detached from a holder plate (12) for polishing by a simple operation. The optical fiber end-surface polishing device, having a ferrule fixing device, simultaneously polishes the end surfaces of a plurality of ferrules with optical fibers fixed to and supported by a holder plate (12). The device includes ferrule accommodating sockets (13) provided on the holder plate and having through holes (16) for accommodating ferrules; and ferrule presser levers (18) supported by stationary shafts (17) substantially parallel to the through holes and biased toward descent by biasing devices (21), wherein each of the ferrule presser levers is movable between an angular position where the ferrules inserted into the associated ferrule accommodating sockets are downwardly pressed and an angular position where the polished ferrules can be detached.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber end-surface polishing device according to the preamble of claim 1. 2. Description of the Related Art The present inventor has made several inventions regarding an optical fiber end-surface polishing device for simultaneously polishing a plurality of optical fibers. Among them are the following four inventions, all of which relate to a polishing device capable of simultaneously polishing the end surfaces of a plurality of optical fibers: U.S. Patent No. 4,831,784 "POLISHING APPARATUS FOR END SURFACES OF OPTICAL FIBERS" U.S. Patent No. 4,979,334 "OPTICAL FIBER END SURFACE POLISHING DEVICE" U.S. Patent No. 5,216,846 "METHOD AND APPARATUS FOR GRINDING FOREMOST END OF A FERRULE" Japanese Patent Laid-Open No. 6-179161 (US Ser.No. 08/019,303) "APPARATUS FOR GRINDING END FACES OF FERRULES TOGETHER WITH OPTICAL FIBERS EACH FIRMLY RECEIVED IN FERRULES" These inventions relate to a polishing device in which the end surface of an optical fiber to be polished is pressed against a polishing disc while effecting a relative movement composed of turning and revolution, thereby polishing the end surface of the optical fiber. Fig. 3 is a plan view of a polishing holder or holder plate in a conventional optical fiber end-surface polishing device for simultaneously polishing the end surfaces of a plurality of optical fibers; and Fig. 4 is a sectional view showing a ferrule fixed to the holder plate of the conventional polishing device shown in Fig. 3. A holder plate for polishing 1 is formed as a disc and has at its center a cylindrical hub section 2 into which a holding shaft (not shown) is inserted. Arranged along the circumference of a concentric circle, indicated by the dashed line E, are a plurality of mounting members 3 of the same structure for mounting devices with optical fibers. The sectional view of Fig. 4, taken along the line A-A' of Fig. 3, shows an example of the polishing holder for polishing, perpendicular to the axis, an end surface 6 of an FC-type ferrule 5 to which an optical fiber 4 is attached. Each mounting member 3 has an accommodating socket 7 for fixing the ferrule and a cap nut 9. The socket 7 for fixing the ferrule has at its center a through hole for accommodating the FC-type ferrule 5 and is forced into a hole provided in the holder plate 1 and secured therein. Further, a male screw 8 is provided in the outer periphery of the socket 7 for fixing the ferrule. The cap nut 9 has a slit 10 and a female screw to be engaged with the male screw 8 to fix the FC-type ferrule 5. The operator tightens the cap nut 9 to fix the optical fiber ferrule 5 to the holder plate 1, and presses the end surface 6 of the ferrule 5 against the polishing disc 11 to perform polishing by a relative movement such that the tip end of the ferrule 5 with an optical fiber describes an arcuate trajectory. In many conventional optical fiber end-surface polishing devices, the mounting of the ferrule 5 with an optical fiber is effected by inserting the ferrule 5 into the through hole of the ferrule accommodating socket 7 and then engaging the slitted cap nut 9 with the male screw 8 provided on the outer peripheral surface of the socket, as described above. This structure has a problem in that the slitted cap nut 9 is liable to be lost during operation and that it takes 10 to 20 seconds per unit to effect fixation by tightening the nuts. Further, whereas the principal dimensions of the - currently-used optical connector ferrules are: an outer diameter of 2.5 mm and an effective length of 8 mm, an optical connector ferrule whose dimensions are approximately reduced in half is being developed and put into practical use with the progress of a reduction in size of optical circuit systems. In this regard, the conventional structure based on screwing as described above is expected to become too minute, making the mounting operation rather difficult. EP 0 484 733 A3 discloses an optical fiber end-surface polishing device comprising the features of the preamble of claim 1. In this prior art device an optical fiber ferrule can be fixed to the holder plate simply by inserting the optical fiber ferrule into a through hole on the holder plate and turning ferrule pressure means from a first angular position where the ferrule has been inserted into the holder plate to a second angular position where the ferrule is pressed against the holder plate and thus against the polishing surface. This provides a simple fixing mechanism for ferrules onto holder plates. The device is however relatively heavy and cumbersome. SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple optical fiber end-surface polishing device having an improved ferrule fixing means which allows ferrules with optical fibers to be attached to and detached from a holder plate for polishing by an easy operation. This object of the invention is accomplished by an optical fiber end-surface polishing device comprising the features of claim 1. An advantageous embodiment is provided in claim 2. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view showing a holder plate in an optical fiber end-surface polishing device according to an embodiment of the present invention which has a ferrule fixing means on the holder plate; Fig. 2 is a sectional view of the ferrule fixing means of the embodiment shown in Fig. 1; Fig. 3 is a plan view of a holder plate in a conventional optical fiber end-surface polishing device; and Fig. 4 is a sectional view showing a ferrule fixed to the holder plate of the conventional polishing device shown in Fig. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will now be described in more detail with reference to the drawings. Fig. 1 is a plan view of a holder plate in an optical fiber end-surface polishing device according to an embodiment of the present invention, and Fig. 2 is a sectional view of the ferrule fixing means of the embodiment. A holder plate 12 for polishing is formed as a thin and flat disc. A plurality of ferrule accommodating sockets 13, each having a through hole 16 into which a ferrule 15 with an optical fiber 14 attached thereto is inserted, are arranged along the circumference of a circle E on the flat surface of the holder plate 12 and fastened thereto by means of screws. Stationary shafts 17, each having a screw at its lower end, are vertically mounted on the holder plate 12 for polishing so as to be adjacent to the ferrule accommodating sockets 13. A ferrule presser lever 18 is provided on each stationary shaft 17 so as to be rotatable around it. Each ferrule presser lever 18 is provided with a cylindrical operating knob 19 integrally formed in the central portion thereof. Each operating knob 19 has a hole into which the stationary shafts 17 is inserted and which can accommodate a compression coil spring 21. Next, the procedures for fixing the ferrule 15 with an optical fiber to the holder plate will be described. First, outer edge portions (or tip ends) 18a of each ferrule presser lever 18 are at least positioned such that they do not cover the through holes 16 of the associated ferrule accommodating sockets 13, as indicated, for example, at C-C' of Fig. 1, and ferrule 15 with optical fibers are inserted into the through holes 16 of these ferrule accommodating sockets 13. Next, the knob 19 is raised and turned so as to bring the ferrule presser lever 18 to a position indicated at B-B', where the outer edge portions 18a of the presser lever 18 are in alignment with the upper surfaces of flanges 24 of the ferrules 15 with optical fibers. Then, the knob 19 is released. The flanges 24 of the ferrules 15 with optical fibers are pressed by the lower surfaces of the outer edge portions 18a of the ferrule presser lever 18, which is downwardly pressurized by the compression coil springs 23. As a result, each ferrule 15 with an optical fiber can be independently and uniformly brought into press contact with the holder plate 12 for polishing and secured thereto. After the polishing, the operating knob 19 is raised, and the outer edge portions 18a of the presser lever 18 is moved to the position indicated at C-C' in Fig. 1, thereby enabling the ferrules 15 with optical fibers to be removed from the holder plate. The embodiment that has been described in detail above allows various modifications without departing from the scope of the present invention. While in the above embodiment one ferrule presser lever presses two ferrules, it is also possible for one presser lever 18 to press one or three or more ferrules. The optical fiber end-surface polishing device of the present invention having a ferrule fixing means uses a presser lever biased by a spring force or the like as the means for attaching and detaching a ferrule with an optical fiber to and from a holder plate for polishing. The attaching and detaching operations are effected by turning the lever, so that the operations are very easy to perform. This makes the device particularly suitable for the mounting and fixing of a ferrule with an optical fiber having minute dimensions.

Claims: An optical fiber end-surface polishing device for simultaneously polishing end-surfaces of a plurality of optical fibers (14), comprising: a) a holder plate (12); b) means associated with the holder plate for fixing and supporting a plurality of ferrules (15), each of the ferrules having an optical fiber (14) attached thereto, said means comprising through holes (16) and imposing a limit to the descent of the ferrules; c) shaft means positioned on the holder plate (12) and extending in a direction substantially parallel to that of the through holes (16); d) ferrule presser means supported by the shaft means and including operating knob means around the shaft means; and e) biasing means for urging the ferrule presser means towards the holder plate (12), the biasing means comprising compression spring means (21) acting on the ferrule presser means, f) whereby said ferrule presser means can be moved against a biasing force of the compression spring means (21) by moving the operating knob means, and g) whereby said ferrule presser means is movable between a first angular position where the ferrules (15) inserted into the fixing and supporting means are pressed towards the holder plate (12) by the ferrule presser means and a second angular position where the ferrules (15) are detachable from said fixing and supporting means, characterized in that h) the fixing and supporting means comprise a plurality of ferrule accomodating sockets (13) inserted into the holder plate (12), each of said sockets (13) providing one of said through holes (16) for accomodating one of the ferrules (15); i) the shaft means comprise a plurality of shafts (17), each being stationarily connected to the holder plate (12); j) the ferrule presser means comprise a plurality of ferrule presser levers (18), each being rotatably supported on one of the stationary shafts (17); k) the knob means comprise a plurality of knobs (19), each being connected to one of the ferrule presser levers (18); and l) the compression spring means comprise a plurality of compression springs (21), each acting between one of the stationary shafts (17) and the associated ferrule presser lever (18). The optical fiber end-surface polishing device according to claim 1, wherein said stationary shafts (17) are positioned each between a pair of sockets (13), and wherein the presser levers comprise a plurality of lever sections, each of said lever sections extending to a peripheral edge of one of said ferrule accommodating sockets (13) for fixing simultaneously the ferrules (15) with optical fibers (14) attached thereto accommodated by said pair of sockets.

Inventors: TAKAHASHI MITSUO, TAKAHASHI, MITSUO
Applicants: SEIKO GIKEN KK, SEIKOH GIKEN CO., LTD.
Application year: 1995
Main classification: B24B19
IPC codes: B24B19, G02B6