JPH0321890Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a device for processing the end face of an optical fiber into various curved surfaces, and in particular, it relates to a device for processing the end face of an optical fiber into various curved surfaces with high precision and efficiency. The present invention relates to an optical fiber end face grinding device suitable for processing.

[Background technology and its problems]

In optical communication systems using optical fibers, it is important to efficiently make light emitted from a light source enter the optical fiber. for that,
A lens is placed between the light source, such as an LD (semiconductor laser) or an LED (light emitting diode), and the end face of the optical fiber, or the end face of the optical fiber is made spherical, spherical, or tapered. ing. Among these, forming the end face of the optical fiber into a curved shape such as a sphere or a spherical shape has the advantage of high efficiency and the effect of suppressing reflected return light, which is excellent in practical use.

As methods for processing the end face of an optical fiber into a curved surface, there are methods such as etching and electric discharge machining, in addition to a method in which the end of the optical fiber is melted with heat and shaped into a curved surface by the action of surface tension. but,
Either way, the yield is extremely low.
In addition, it took a long time to process, so it could not be applied immediately to production.

Therefore, a method of mechanical grinding was attempted. In the case of mechanical grinding, while rotating the optical fiber,
Since the end face of the optical fiber is ground into a curved surface using a grindstone, it is important to rotate the processed end face of the optical fiber without misalignment. Conventionally, methods shown in FIGS. 8 and 9 are known as methods for this purpose.

In the method shown in FIG. 8, a holder 5 is attached to the tip of a hollow main shaft 4, and an insertion hole 6 of the holder 5 is attached.
The processed end of the optical fiber core wire 3 whose outer periphery is coated with the primary coating 2A and the secondary coating 2B is inserted into the inner periphery of the optical fiber 1, and a fixing material 7 (for example, electron wax, etc.) is injected into the inner periphery of the optical fiber 1. After fixing the fiber core wire 3 to the holder 5, the optical fiber 1
The optical fiber 1 is centered so that the axis of the optical fiber 1 coincides with the center axis of rotation, thereby reducing the deflection of the optical fiber 1. This method had the problem of extremely poor workability because centering and wax treatment took a long time (approximately 30 minutes).

The method shown in FIG. 9 involves forming a high-precision holding hole 8 with a slightly larger diameter than the diameter of the optical fiber 1 at the tip of the holder 5 and having no eccentricity. Insert the optical fiber 1
This is designed to reduce the runout. Although this method has slightly improved workability compared to the method shown in FIG. As a result, there was a problem in that the machining end face would run out due to the influence of this gap. In other words, as shown in FIG. 10, even if the vicinity of the processed end surface of the optical fiber 1 is held by the holding hole 8, if there is a gap between the holding hole 8 and the optical fiber 1, the fiber behind it will deflect. There was a problem in which the machined end surface of the tip was affected by runout.

[Purpose of invention]

In view of these conventional problems in mechanical grinding, the present invention proposes an optical fiber end face grinding method that can process the end face of an optical fiber into a desired curved shape with high precision and in a short time without misalignment. Our goal is to provide processing equipment.

[Means and actions for solving problems]

Therefore, in the present invention, as a device for grinding the end face of an optical fiber whose outer periphery is coated into a curved surface,
A base, a fiber holding unit that holds the vicinity of the processed end face of the optical fiber provided on the base and rotates the optical fiber, and an end face of the optical fiber provided on the base and held by the fiber holding unit. a grindstone unit having a grindstone for grinding into a curved surface, the fiber holding unit comprising:
The basic structure includes a hollow main shaft rotatably supported by the base, a drive device for rotating the main shaft, and a holder fixed to the tip of the main shaft.

By providing a holding hole on the tip side of the holder to hold the vicinity of the processed end face of the optical fiber over a certain length on the rotation axis of the main shaft, the optical fiber to be processed can be prevented from bending near the processed end face. Ensure fiber positioning accuracy.

Furthermore, a guide hole having a larger diameter than the holding hole is formed on the proximal end side of the holder, and a guide tube for guiding the optical fiber inserted into the holding hole is removably fitted into the guide hole. By providing an insertion hole in the center of the tube to fit and hold the outer peripheral coating of the optical fiber, when installing the optical fiber, the guide tube is taken out and the optical fiber coating is fitted into the insertion hole, and the guide tube is inserted into the guide tube. When inserted into the guide hole, the optical fiber held is automatically aligned with the holding hole and inserted, thereby increasing the safety of the easily broken optical fiber and the ease and speed of the work of inserting it into the thin holding hole. secure.

Here, the features of the present invention will be described in more detail below.

The present inventor believes that in the state shown in FIG. 10, if there is a gap between the holding hole 8 and the optical fiber 1, the processed end face will deflect due to the influence of the deflection of the fiber behind the gap. is related to the length of the holding hole 8.

As shown in FIG. 2, it has been found that by providing another holding hole 8A for holding the optical fiber 1 behind the holding hole 8, the influence of deflection of the fiber further back can be suppressed. The suppressing effect appears when the distance l between the holding holes 8 and 8A is 1.5 mm or more. Therefore, in the present invention, as shown in FIG. 1, a holding hole 11 is provided in the holder 5 that holds the vicinity of the processed end surface of the optical fiber 1 on the same axis as the rotational axis of the main shaft 4 at a length longer than a certain length (1.5 mm or more). This suppresses the influence of the deflection of the rear fiber and allows the processed end face to be processed into a desired shape with high precision.

However, it is not easy to actually insert the processed end surface of a fine optical fiber into the holding hole of a holder attached to the main shaft, and if the tip hits somewhere by mistake, it will easily break. Therefore, in this proposal,
As shown in FIG. 1, a guide hole 12 is formed in the holder 5 on the same axis as the rotational axis of the main shaft 4, and an insertion hole is inserted into the guide hole 12 to fit with the outer diameter of the coatings 2A and 2B of the optical fiber 1. By fitting a guide tube 14 having a hole 13 in a removable manner, the optical fiber can be set in the holder in a short time.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 shows the appearance of the optical fiber end face grinding apparatus of this embodiment.

The processing apparatus is roughly divided into a base 21, a fiber holding unit 31 which is provided on one side of the upper surface of the base 21 and holds the vicinity of the processed end surface of the optical fiber 1 and rotates the optical fiber 1, and the base 21. stand 21
A grindstone unit 71 having a grindstone 70 provided on the other side of the upper surface for grinding the end face of the optical fiber 1 held by the fiber holding unit 31 into a curved surface.
A microscope unit 10 is provided at the rear of the upper surface of the base 21 via a support 100 for confirming the position of the grindstone 70 with respect to the processed end surface of the optical fiber 1.
It is composed of 1.

The fiber holding unit 31 includes a support stand 32 fixed to one side of the upper surface of the base 21, and a main shaft fixed on the support stand 32 via a table 33 that moves back and forth in the Z-axis direction (left and right directions in the figure). It includes a head 34 and a fiber holding device 35 rotatably supported by the spindle head 34 along the Z-axis direction.

The fiber holding device 35, as shown in FIG.
The main shaft 37 has a hollow shaft shape and is rotatably supported by the main shaft head 34 via a bearing sleeve 36.
An air bearing member 39 is interposed between the main shaft 37 and the bearing sleeve 36, and the air bearing member 39 has an air jet hole 38 at a predetermined angular position in the circumferential direction that opens toward the outer peripheral surface of the main shaft 37 on its front end side. Also, an air bearing member 41 having air jet holes 40 at predetermined angular positions in the circumferential direction that open toward the outer circumferential surface of the main shaft 37 and the front end surface of the flange 37A provided in the middle of the main shaft 37, respectively, on the rear end side. is interposed.

Further, a compressed air introduction ring 43 is coupled to the rear end surface of the bearing sleeve 36 via a spacer 42, and is in contact with the rear end surface of the flange portion 37A.
The compressed air introduction ring 43 has an air passage 44 formed toward the center, and an air jet hole for jetting the compressed air supplied through the air passage 44 to the rear end surface of the flange 37A. 45 are opened at predetermined angular positions in the circumferential direction.
Further, the bearing sleeve 36 has an air flow that communicates with the air passage 44 and supplies the compressed air guided to the air passage 44 to the air jet holes 38 and 40 of the respective air bearing members 39 and 41. A channel 46 is formed. Thereby, the main shaft 37 is rotatably supported by air bearings in both the radial direction and the thrust direction.

Further, on the rear end surface of the compressed air introduction ring 43, a case 48 having heat dissipation fins 47 on the outer peripheral surface is provided.
is installed. Case 48 and the main shaft 3
A motor 49 serving as a drive device for rotating the main shaft 37 is built in between the rear end portion of the main shaft 37 and the rear end portion of the main shaft 37 . The motor 49 includes a stator 50 fixed inside the case 48, and a rotor 51 fixed to the outer periphery of the main shaft 37 and facing the stator 50 with a predetermined clearance. moreover,
A front holder 52 is attached to the front end of the main shaft 37, and a rear holder 53 is attached to the rear end of the main shaft 37.

The tip holder 52 is a first holder 52A attached to the front end of the main shaft 37, as shown in FIG.
A cap nut 5 is attached to the front end of this first holder 52A.
5, and a second holder 52B detachably attached via the second holder 52B. The first holder 52A includes
A first guide hole 54 is formed coaxially with the rotational axis of the main shaft 37 . The second holder 52B is
A holding hole 57 whose tip part is formed in a conical shape whose diameter gradually becomes smaller and which holds the vicinity of the processed end surface of the optical fiber 1 for a certain length or more along the same axis as the rotational axis of the main shaft 37; Holding hole 5
The second guide hole 58 has a diameter larger than the diameter of the second guide hole 7 and smaller than the diameter of the first guide hole 54.

The length of the holding hole 57 is such that the deflection of the optical fiber 1 behind it does not affect the tip, for example, when the diameter of the secondary coating 2B is about 3 mm and the diameter of the optical fiber 1 is about 0.125 mm, the length is 1.5 mm. In this case, it is 2 mm or more. In addition, the second holder 52
A slit 59 is formed at the tip of B, and the diameter of the holding hole 57 can be enlarged or reduced by a cap nut 60 screwed onto the outer periphery of the second holder 52B.

A guide tube 61 is fitted into the first guide hole 54 and the second guide hole 58 so as to be insertable and removable. The guide cylinder 61 includes a first cylinder part 62 having an outer diameter that fits into the second guide hole 58 and a second cylinder part 62 whose outer diameter has a diameter that fits into the first guide hole 54. 63, and a third cylindrical portion 64 having an outer diameter larger than the diameter of the second cylindrical portion 63. In addition, at the center of the guide tube 61,
A first insertion hole 65 with a diameter that fits with the outer diameter of the primary coating 2A surrounding the optical fiber 1, a second insertion hole 66 with a diameter that fits with the outer diameter of the secondary coating 2B, and A third insertion hole 67 having a diameter larger than that of the insertion hole 66 is sequentially formed. In the third insertion hole 67,
A front end portion of a pipe 68 having an inner diameter slightly larger than the outer diameter of the secondary coating 2B is fitted. pipe 68
The rear end portion is fitted into an engagement hole 69 of the rear holder 53, as shown in FIG.

The grindstone unit 71 includes a rotary table 72 that is rotatably provided on the other side of the upper surface of the base 21 and is rotatable about an axis perpendicular to the rotational axis of the main shaft 37, and a rotary table 72 that rotates the rotary table 72. an X-Y drive device 73 provided on the rotary table 72 and movable in directions perpendicular to the rotation axis of the rotary table 72 and perpendicular to each other by means of two servo motors 74X and 74Y. table 74
A whetstone having a whetstone shaft head 75 fixed on this X-Y table 74, and a whetstone 70 rotatable on this whetstone shaft head 75 and provided at right angles to the rotation axis of the rotary table 72. and a shaft 76.

The drive device 73 includes a worm wheel 77 provided coaxially with the rotary table 72 and a worm 78 meshed with the worm wheel 77.
and a motor 79 that rotates the worm 78 in forward and reverse directions. Therefore, when the motor 79 is rotated in the forward and reverse directions, the rotary table 72 is rotated in the forward and reverse directions via the worm 78 and the worm wheel 77, so that the grindstone shaft 76 reciprocates about the rotation axis of the rotary table 72. Rotated.

As shown in FIG. 7, the grindstone shaft 76 is rotatably supported by the grindstone shaft head 75 via a bearing sleeve 80. Between the bearing sleeve 80 and the grindstone shaft 76, there is an air bearing member having a retaining ring 81 on its front end side and an air jet hole 82 opening toward the outer peripheral surface of the grindstone shaft 76 at a predetermined angular position in the circumferential direction. 83 is interposed therein, and an air jet hole 84 that opens toward the outer circumferential surface of the grinding wheel shaft 76 and the front end surface of the flange 76A provided at the rear end of the grinding wheel shaft 76 is provided on the rear end side. An air bearing member 85 is interposed at a predetermined angular position in the direction. Compressed air is supplied to the air jet hole 82 through an air supply port 86 formed in the bearing sleeve 80 and an air passage 87 formed in the retaining ring 81. On the other hand, compressed air is supplied to the air outlet 84 through an air supply port 88 and an air passage 89 formed in the bearing sleeve 80 .

Further, an end plate 91 is coupled to the rear end surface of the bearing sleeve 80 via a spacer 90, and is in contact with the rear end surface of the flange portion 76A. The end plate 91 includes
An air flow path 92 communicating with the air flow path 89 is formed, and an air jet hole 93 for jetting compressed air supplied through the air flow path 92 to the rear end surface of the flange 76A is formed at a predetermined angle. There are openings in each position. As a result, the grindstone shaft 76 is
It is rotatably supported by air bearings in both the radial direction and the thrust direction.

Moreover, between both air bearing members 83 and 85, between the bearing sleeve 80 and the grindstone shaft 76,
A motor 94 serving as a drive device for rotating the grindstone shaft 76 is built-in. The motor 94 has a stator 95 fixed inside the bearing sleeve 80.
and a rotor 96 fixed to the outer periphery of the grindstone shaft 76 and facing the stator 95 with a predetermined clearance.

Next, the operation of this embodiment will be explained.

When grinding the end face of the optical fiber 1, the optical fiber core 3 is first set in the fiber holding unit 31. For this, the rear holder 5
3. Pull out the pipe 68 and the guide tube 61 from the main shaft 37, and sequentially pass the optical fiber core wire 3 through them so that the tip of the optical fiber 1 protrudes from the first insertion hole 65 of the guide tube 61. In this state, the primary coating 2
A is inserted into the first insertion hole 65 of the guide tube 61, and the secondary coating 2B is inserted into the second guide hole 66 of the guide tube 61 and the pipe 68.

When the shaft in this state is inserted from the rear end of the main shaft 37, the second cylindrical portion 63 of the guide tube 61 is first fitted into the first guide hole 54 of the first holder 52A, and then the guide tube The 61 first cylindrical portions 62 are fitted into the second guide holes 58 of the second holder 52B. Therefore, the outer diameter of the primary coating 2A is the same as that of the first cylindrical portion 62 and the second guide hole 58, and the outer diameter of the secondary coating 2B is the same as that of the second cylindrical portion 63 and the first guide hole 54. Since the optical fibers 1 and 2 are centered, if the optical fibers 1 are further inserted, the tips of the optical fibers 1 can be accurately projected through the holding holes 57 of the second holder 2B. Thereafter, the cap nut 60 is screwed together to hold the tip of the optical fiber 1 in the holding hole 57 of the second holder 52B.

After the optical fiber core wire 3 is set in the fiber holding unit 31 in this way, the tip of the optical fiber 1 is positioned offset from the center of the rotary table 72 by a necessary amount according to the shape of the end face. This is done by moving the spindle head 34 forward and backward in the Z-axis direction using a motor (not shown). Also, whetstone 7
0 is also positioned according to the end face shape. This includes:
While checking the position of the grindstone 70 with respect to the optical fiber 1 using the microscope unit 101,
This is done by moving the X-Y table 74 in directions perpendicular to each other by driving Y.

Once the grinding wheel 70 has been positioned relative to the optical fiber 1, the motor 49 of the fiber holding unit 31 and the motor 94 of the grinding wheel unit 71 are driven, respectively, and commands from a known NC device or in the case of a spherical shape with a single radius are driven. In this step, the drive device 73 is driven by a command from the sequencer. Then, the rotary table 72 rotates, so the whetstone 7
0, the end face of the optical fiber 1 is ground into a spherical shape.

Therefore, according to this embodiment, the length of the holding hole 57 of the second holder 52B that holds the vicinity of the processed end surface of the optical fiber is long, 2 mm in this case, so that the length of the fiber behind the holding hole 57 is increased. Since the processed end face does not run out due to the influence of runout, the end face of the optical fiber 1 can be ground with high precision.

In addition, since the optical fiber 1 is inserted into the tip holder 52 using the primary coating 2A and secondary coating 2B that cover the optical fiber 1 as guides, the tip of the optical fiber 1 can be inserted into the second holder 52 without hitting other parts. It can be accurately inserted into the holding hole 57 of the holder 52B.

Furthermore, since the main shaft 37 of the fiber holding unit 31 and the grindstone shaft 76 of the grindstone unit 71 are supported by air bearings, the finishing accuracy of the processed end surface of the optical fiber 1 can be improved. By the way, when the air bearing runout was 0.01 μm, the finished surface accuracy R _nax was 0.01 μm.

In the above embodiment, the motors 49, 79 for rotating the main shaft 37 and the grindstone shaft 76 are built into each unit, but these may be mounted externally.

Further, the first holder 52A and the second holder 52B do not need to be constructed separately as in the above embodiment, but may be integrated.

[Effect of idea]

As described above, according to the present invention, it is possible to grind the end face of an optical fiber into a desired curved shape in a short time with high precision and without misalignment.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the main parts of the invention, Fig. 2 is a diagram showing the principle of the invention, Figs. 3 to 7 show an embodiment of the invention, and Fig. 3 is a perspective view. Figure 4 is a cross-sectional view showing the main parts of the fiber holding unit, Figure 5 is an enlarged cross-sectional view taken along the - line in Figure 4,
The figure is a sectional view taken along the line -- in FIG. 4, and FIG. 7 is a sectional view showing the main parts of the grindstone unit. Figure 8 to 1
FIG. 0 shows a conventional example, FIGS. 8 and 9 are cross-sectional views showing conventional holders, respectively, and FIG. 10 is a diagram for explaining problems caused by the holder of FIG. 9. 1... Optical fiber, 2A... Primary coating, 2B...
... Secondary coating, 3 ... Optical fiber core wire, 4 ... Main shaft, 5 ... Holder, 11 ... Holding hole, 12 ... Guide hole, 13 ... Insertion hole, 14 ... Guide hole, 21 ...
...Base, 31...Fiber holding unit, 37...
... Main shaft, 49 ... Motor, 52A ... First holder, 52B ... Second holder, 54 ... First guide hole, 57 ... Holding hole, 58 ... Second guide hole,
61... Guide tube, 65... First insertion hole, 66...
... second insertion hole, 70 ... grindstone, 71 ... grindstone unit, 71 ... rotary table, 73 ... drive device, 76 ... grindstone shaft, 94 ... motor.

Claims (1)

[Claims for Utility Model Registration] (1) A device for grinding the end face of an optical fiber whose outer periphery is coated into a curved surface, comprising a base and a base mounted on the base to hold the vicinity of the processed end face of the optical fiber. and a fiber holding unit for rotating the optical fiber; and a grinding wheel unit provided on the base and for grinding the end face of the optical fiber held by the fiber holding unit into a curved surface, the fiber holding unit comprising: A hollow shaft-like main shaft rotatably supported by the base, a drive device for rotating the main shaft, and a holder fixed to the tip of the main spindle, and the rotating shaft of the main spindle is provided on the tip side of the holder. A holding hole is formed on the line to hold the vicinity of the processed end surface of the optical fiber over a certain length, and a guide hole having a larger diameter than the holding hole is formed on the proximal end side of the holder. A guide tube for guiding an optical fiber inserted into a holding hole is fitted in a removable manner, and the guide tube has an insertion hole in the center for fitting and holding an outer periphery of the optical fiber. Processing equipment. (2) An optical fiber end face grinding device according to claim 1, characterized in that the length of the holding hole of the holder is 1.5 mm or more. (3) Utility Model Registration The optical fiber end face grinding device according to claim 1 or 2, characterized in that the main shaft of the fiber holding unit is rotatably held by an air bearing. (4) Claims 1 to 3 of the utility model registration claim, wherein the grindstone unit is rotatably provided on the base so as to be rotatable about an axis perpendicular to the rotation axis of the main shaft. table and
a drive device for rotating the rotary table; a grindstone shaft having a grindstone rotatable on the rotary table via an air bearing and provided perpendicularly to the rotation axis of the rotary table; 1. An optical fiber end face grinding device comprising: a drive device for rotating an optical fiber;