JP3388895B2 - Optical fiber leakage detector for optical fiber - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber for use in receiving an optical signal transmitted from one end to the other end of the optical fiber. The present invention relates to a light leakage detection device. 2. Description of the Related Art A light leakage detecting device for an optical fiber core utilizes a phenomenon that, when an optical fiber core is bent halfway, light transmitted from the bent portion leaks. The amount of light leaking from the bent portion of the optical fiber varies depending on the bending radius, bending length, stress, and the like, and generally increases as the bending radius decreases, and tends to increase in proportion to the bending length. . The conventional light leakage detecting device uses a jig for keeping the bending radius and the bending length of the optical fiber core constant in order to obtain the amount of leakage light required for detection. There are various types of optical fiber core wires depending on the outer diameter and thickness of the coating. Typical examples include an optical fiber core coated with a UV resin (ultraviolet curable resin) having an outer diameter of 0.25 mm, a tape-shaped multicore optical fiber coated with a UV resin having a thickness of 0.4 mm, and the like. [0005] The amount of light leaking from the bent portion of the optical fiber core varies greatly depending on the type (cross-sectional size) of the optical fiber core even when the same jig is used. For this reason, in the conventional light leakage detection device, it is necessary to prepare a jig having different dimensions depending on the type of the optical fiber core as a jig for bending the optical fiber core. In addition, when light leakage detection is performed on a plurality of types of optical fiber core wires, there is an inconvenience that the jig must be replaced each time. SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus capable of detecting light leakage of a plurality of types of optical fiber cores by a simple switching operation without replacing parts in view of the above problems. In order to achieve this object, a light leakage detecting device for an optical fiber core according to the present invention comprises two fixed fulcrums on an upper surface for supporting the optical fiber core at a predetermined interval. A fixed base having a light detecting element installed between the two fixed fulcrums, and a rotatable connection centered on an axis pin to the fixed base. An operation lever having a movable fulcrum that pushes down the optical fiber core wire, attached between the fixed base and the operation lever,
A spring member that generates a force that presses the movable fulcrum of the operation lever against the optical fiber core wire, is screwed so as to vertically penetrate between the shaft pin of the operation lever and the movable fulcrum, and the lower end abuts on the fixed base, and a switching member for switching the height of the movable fulcrum for the fixed support by screwing amount, depending the screwing amount of the switching member on the type of optical fiber, the outer
It is characterized by including a stopper which is determined in advance so as to correspond to the diameter or the thickness . In this apparatus, an optical fiber core is placed on two fixed fulcrums on a fixed base, and a central portion between the fixed fulcrums is pushed by one movable fulcrum on the operation lever side to thereby provide an optical fiber core. To bend. The movable fulcrum of the operating lever is always going down due to the force of the spring member, but its lowest position (the height of the movable fulcrum relative to the fixed fulcrum) depends on the amount of screwing of the switching member whose lower end abuts against the fixed base into the operating lever. Is determined. That is, the degree of bending of the optical fiber core is determined by the screwing amount of the switching member. Therefore, by determining the screwing amount of the switching member in advance in accordance with the type of the optical fiber core, it is possible to detect light leakage of a plurality of types of optical fiber cores only by switching the switching member. Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 7 show one embodiment of the present invention. In the figure, reference numeral 11 denotes a fixed base, and 13 denotes an operation lever rotatably connected to the fixed base 11 around a horizontal shaft pin 15. A photodiode 17 for light detection and a storage case 19 are provided on the top surface of the fixed base 11 on the distal end side. The upper edge of the storage case 19 slightly protrudes from the upper surface of the fixed base 11. The optical fiber core F is placed on the upper end edge of the storage case 19 so as to cross the fixed base 11 orthogonally to the central axis of the storage case 19 (see FIG. 3). That is, the upper end edge of the storage case 19 constitutes two fixed fulcrums 21a and 21b on which the optical fiber core F is placed. On the other hand, a column member 23 is attached to the lower surface of the operation lever 13 at a position facing the photodiode 17 in a direction orthogonal to the optical fiber core F (see FIG. 3). The lower surface of the cylindrical member 23 protrudes from the lower surface of the operation lever 13. The lower surface of the cylindrical member 23 defines a movable fulcrum 25 for bending the optical fiber core F at the center between the two fixed fulcrums 21a and 21b. Make up. The upper surface of the fixed base 11 on the rear end side and the operation lever 13
A coil spring 27 is inserted in a compressed state between the lower end side lower surface and the lower end. The repulsive force of the coil spring 27 serves to push down the movable fulcrum 25 of the operation lever 13 and press it against the optical fiber core F. When the rear end side of the operation lever 13 is pressed down against the repulsive force of the coil spring 27, the cylindrical member 23 is lifted up as shown in FIG. 5, so that the optical fiber core F is placed on the fixed fulcrums 21a and 21b in this state. Is placed. The shaft pin 15 of the operating lever 13 and the cylindrical member 23
A male screw 29 is screwed in between so as to penetrate vertically. The lower end of the male screw 29 abuts against the fixed base 11 due to the repulsive force of the coil spring 27. A switching lever 31 for rotating the male screw 29 is fixed to the upper end of the male screw 29. When the amount of screwing of the male screw 29 is changed by rotating the switching lever 31, the protrusion height of the male screw 29 from the lower surface of the operation lever 13 changes, so that the height of the movable fulcrum 25 with respect to the fixed fulcrums 21a and 21b changes. . The rotation angle of the switching lever 31 is regulated by a stopper 33 protruding from the upper surface of the operation lever 13. When the switching lever 31 is at the position indicated by the solid line in FIG. 2, the height of the movable fulcrum 25 with respect to the fixed fulcrums 21a and 21b is as shown in FIGS. 1 and 4, and for example, an optical fiber core having an outer diameter of 0.40 mm. The wire is bent (the same applies to a 0.40 mm-thick tape-shaped optical fiber core wire) and becomes in a state suitable for detecting light leakage. The light leaked from the optical fiber core F is a photodiode 17
And transmitted to an optical intercom (not shown). When the switching lever 31 is rotated in the direction of arrow C in FIG. 2 to the position indicated by the alternate long and short dash line, the height of the movable fulcrum 25 with respect to the fixed fulcrums 21a and 21b becomes as shown in FIGS. The state is suitable for detecting light leakage by bending an optical fiber of 0.25 mm. As described above, this apparatus can detect light leakage of two types of optical fibers by switching the switching lever 31. The above is one embodiment of the present invention, and the present invention is not limited to this, and includes, for example, the following embodiments. The stop position of the switching lever 31 is set at three or more positions to detect light leakage of three or more types of optical fibers. A shaft pin is provided on the rear end side of the fixed base and the operation lever,
A tension coil spring is provided in the middle. Uses leaf springs instead of coil springs. A fixed fulcrum is provided separately from the upper edge of the photodiode storage case. An optical fiber core positioning mark or positioning guide is provided on the upper surface of the fixed base. As described above, according to the present invention, it is possible to detect light leakage of a plurality of types of optical fiber cores only by switching operation without replacing parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an essential part cutaway front view showing an embodiment of an optical fiber core light leakage detecting device according to the present invention. FIG. 2 is a plan view of the apparatus of FIG. FIG. 3 is a plan view showing a positional relationship between a fixed fulcrum, a movable fulcrum, and an optical fiber in the apparatus shown in FIG. 1; FIG. 4 is a cross-sectional view of the device of FIG. 1 taken along line AA. 5 is a cross-sectional view at the same position as FIG. 4 showing a state where a movable fulcrum of the apparatus of FIG. 1 is lifted. 6 is an essential part cutaway front view showing a state where optical fibers having different sizes are set in the apparatus of FIG. 1; FIG. 7 is a sectional view taken along line BB of FIG. 6; [Description of Signs] 11: Fixed base 13: Operation lever 15: Shaft pin 17: Photodiode 19: Storage case 21a, 21b: Fixed fulcrum 23: Cylindrical member 25: Movable fulcrum 27: Coil screw 29: Male screw 31: Switching lever 33: Stopper

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-1099312 (JP, A) JP-A-63-73208 (JP, A) JP-A 2-58103 (JP, U) JP-A 62-73208 11138 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 11/00-11/02 G02B 6/00 G02B 6/00 336 G02B 6/28

Claims (1)

(57) [Claim 1] On a top surface, two fixed fulcrums supporting an optical fiber core wire at a predetermined interval, and a light detecting element installed between the two fixed fulcrums. And a fixed base having the shaft fixed to the fixed base so as to be rotatable.
An operating lever having a movable fulcrum on the lower surface that pushes down the optical fiber core at the center between the two fixed fulcrums; and a movable fulcrum mounted between the fixed base and the operating lever, for pressing the movable fulcrum of the operating lever against the optical fiber core. A spring member that generates a force, is screwed between the shaft pin of the operation lever and the movable fulcrum so as to penetrate vertically, the lower end abuts against the fixed base, and the height of the movable fulcrum with respect to the fixed fulcrum is determined by the screwing amount. The switching member to be switched, and the screwing amount of the switching member according to the type of the optical fiber,
A light leakage detection device for an optical fiber core, comprising: a stopper which is determined in advance so as to correspond to an outer diameter or a thickness .