JPH06315860A - Constant-pressure polishing device - Google Patents

Abstract

PURPOSE:To hold constant polishing pressure regardless of the length error of a ferrule by fixing the ferrule to a constant-pressure applying mechanism, and operating this mechanism in conjunction with a straight advance drive mechanism when relatively moving the photo-connector ferrule and a polishing wheel for polishing. CONSTITUTION:A polishing wheel 210 is provided with a polishing substrate 200 applied with constant tension to a resin film 201, a ferrule F held by a chuck 6 is pressed to the polishing wheel 210, and the end face of the ferrule F is polished by the relative movement between the polishing wheel 210 and the ferrule F. A constant-pressure applying mechanism 500 is constituted of the chuck 6, a fitting substrate 4, and a rotating motor 7, and the mechanism 500 is driven by a voice coil motor (VCM) constituting a straight advance drive mechanism. The VCM has a magnetic circuit 2 fixed to a fixed substrate 1, a bobbin 3 serving as a drive source is fixed to the fixing substrate 4 slid and guided by a linear guide mechanism 5, and it is driven and controlled by the output of a signal generator 402.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector for mechanically connecting optical fibers to each other, and to a constant pressure polishing apparatus for polishing the tip of a ferrule attached to the joining portion.

[0002]

2. Description of the Related Art As is well known, an optical connector is a splicing device that can be detachably connected to splicing for permanently connecting optical fibers.

Conventionally, various optical connectors have been used which can easily connect and disconnect optical fibers.

For example, in an optical connector for a single core, a ceramic ferrule (made of a ceramic ferrule ( (Reinforcing cylindrical rod for joining) and adhesively fix it, insert this optical connector ferrule into a split sleeve with a precise inner diameter, and then fasten the optical connector ferrule by abutting the tips together. Are known.

The optical connector according to this method has excellent connection characteristics and is therefore widely used in large quantities, especially in the field of optical communication.

In such an optical connector which directly abuts the optical connector ferrule, the tip of the optical connector ferrule has a convex spherical shape in order to improve the optical connection characteristics.

In the current optical connector manufacturing, since this convex spherical surface shape is manufactured by polishing, a polishing machine with high precision and good workability and operability is required.

FIG. 1 shows a first specific example of a conventional polishing machine for polishing an end face of an optical connector ferrule (hereinafter, ferrule) into a convex spherical surface, which has a concave spherical surface 100a. At least three ferrules F are fixed to the polishing platen 100 and the ferrule holder 101 arranged thereon so as to be perpendicular to the concave spherical surface of the polishing surface 100a.

At the time of polishing, the ferrule holder 101
The polishing weight is used as the polishing pressure to feed the polishing agent 102 to the polishing surface 100a of the rotating polishing platen 100, and the ferrule holder 101 is precessed to polish the ferrule end surface.

FIG. 2A shows a second specific example of a conventional polishing machine, in which a resin base film 201 is provided on a polishing base 200 which is driven to rotate with a predetermined tension. The ferrule F on the film 201 at the polishing position.
As shown in FIG. 2B, the tip of the ferrule F is abutted against the abutment block 202 at another location in advance so that the amount of pushing of the tip of the ferrule F is constant, and the ferrule F is gripped by the chuck 6.

During polishing, the ferrule F is rotated forward and backward about its axis while supplying the polishing agent 102 to the upper surface of the rotating film 201 having a constant tension, and the contact position with the film 201 is moved. Gives rocking motion.

FIG. 3 shows a third specific example of a conventional polishing machine. In a polishing disk 300 which is driven to rotate, a polishing sheet 302 or the like is attached to the upper surface of an elastic body 301 such as rubber. The ferrule F attached to the ferrule fitting 101 is pressed by the spring 303.

During polishing, the polishing table 3 rotates and swings.
Ferrule F while supplying the polishing agent 102 to the upper surface of 00
The tip of the ferrule is pressed to polish the end face of the ferrule.

[0014]

However, the conventional polishing machine as described above has the following problems.

That is, in the polishing apparatuses of Conventional Examples 1 and 2 in which the relative distance between the ferrule and the polishing platen is made constant, and an accurate convex spherical surface is produced, the length error of the ferrule greatly affects the polishing accuracy.

Originally, the ferrule length (L) had a manufacturing error of several tens of μm in the length direction even in the initial state, and once polished, there was a maximum polishing error of 0.1 to 0.2 mm in the length direction. Occurs, which becomes a problem during re-polishing.

By the way, since the radius of curvature of the tip of the ferrule is about 20 mm, which is suitable from the optical connection characteristics of the optical connector, in the conventional example 2 and the conventional example 3, the tip of the ferrule F to the film 201 or the elastic body 301 is formed. The radius of curvature of the convex spherical surface can be controlled by defining the pushing amount of

The pushing amount and the radius of curvature in the polishing machine have a relationship as shown in FIG.

That is, as shown in FIG. 4, the radius of curvature changes greatly (5000 μm) with a slight change in the ferrule pushing amount (change of 50 μm), and the ferrule pushing amount is as small as several hundred μm. I know there is.

Therefore, even if the tip position error of the ferrule F is several tens of μm, the pushing pressure to the film 201 fluctuates, and this causes the radius of curvature to fluctuate. In order to obtain the radius, it is necessary to control an indentation amount as small as around 0.3 mm with an accuracy of several tens of μm.

Therefore, in order to precisely polish the end surface of the ferrule with a constant radius of curvature in the convex spherical surface, in the first specific example of the conventional polishing machine, in order to align the tip positions of three or more ferrules attached, Although not shown, it is necessary to attach the ferrule to the holder using a special jig. In addition, in the second specific example of the conventional polishing machine, it is necessary to chuck the ferrule on the butting block, and the chucking operation should be performed carefully with care so that the ferrule position does not shift. There are drawbacks such as requiring complicated work and time, and causing factors that deteriorate polishing accuracy. Further, in the conventional example 3, the pushing amount of the ferrule is to be generated by the bending force of the spring. However, when the length error as described above is present, the bending force fluctuates, so that the curvature radius varies. There is a drawback that.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a constant pressure polishing apparatus which has good workability and can polish the end face of a ferrule with high reproducibility and high precision. is there.

[0023]

In order to achieve the above object, the present invention provides an end face polishing apparatus for a ferrule in which a ferrule and a polishing platen are moved relative to each other, depending on the relative distance between the polishing platen and the ferrule. , The ferrule is fixed to the constant pressure applying mechanism that is driven by the linear drive mechanism that is driven so that the pressing force of the ferrule against the polishing plate does not fluctuate, and the length error of the ferrule or jig is fixed by the linear drive mechanism and the constant pressure applying mechanism. Make sure that a constant polishing pressure can be applied even if there is a mounting error.

That is, in the constant-pressure polishing apparatus of the present invention, a polishing plate, a linear drive mechanism which is located at a position facing the polishing plate and is movable in the axial direction of the ferrule by an electric signal, and by this linear drive mechanism. Is driven,
A constant pressure imparting mechanism unit including a chuck that holds the ferrule and rotates about an axis of the ferrule, and a chuck rotation drive mechanism that rotationally drives the chuck.

[0025]

A constant pressure imparting mechanism portion is constituted by a constant pressure imparting mechanism portion constituted by the chuck and the chuck rotation driving mechanism, and a linear drive mechanism constituted by, for example, a VCM (voice coil motor) directly connected to the constant pressure imparting mechanism portion. At the same time as the tip of the ferrule attached to the upper chuck is pressed against the rotating polishing plate, the ferrule is rotated by the rotation drive mechanism of the chuck to perform polishing.

At this time, the ferrule pressing force of the constant pressure applying mechanism driven by the linear drive mechanism with respect to the polishing plate can be kept constant within the range of the ferrule holding error and the length error. Even if a length error occurs, a reproducible highly accurate convex spherical spherical ferrule end surface can be obtained.

[0027]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 5 is a schematic configuration diagram including a partial cross section showing a first embodiment of the constant pressure polishing apparatus of the present invention.

The polishing board 210 is a polishing base 2 which is driven to rotate.
00, a resin film 201 is provided with a constant tension.

The constant pressure applying mechanism section 500 is a linear drive mechanism 60.
It is driven by a VCM (voice coil motor) that configures 0.

In the VCM, the magnetic circuit 2 is fixed to the fixed substrate 1, and the mounting substrate 4 is fixed to the end of the bobbin 3 serving as a driving source. The mounting substrate 4 is moved in the left-right direction in the figure by the linear guide mechanism 5. It is a movable direction.

The constant pressure applying mechanism 500 comprises a mounting substrate 4, a chuck 6 and a rotary motor 7. A chuck 6 for maintaining a ferrule F is attached to one end of the mounting substrate 4 facing the polishing plate 210. Further, the chuck 6 is configured to be rotationally driven by the rotary motor 7.

The above-described structure operates as follows.

The constant pressure applying mechanism 500 chucks the ferrule F at the position indicated by the chain double-dashed line in the figure (hereinafter referred to as the retracted position).
Remove from.

In order to transfer the constant pressure applying mechanism 500 to the retracted position, a command signal from the pressing force signal generator 402 causes an applied current to flow through the current amplifier 401 to the drive lines 400a to 400b of the bobbin 3 of the VCM, The attachment substrate 4 is abutted against the stopper 1a attached to the fixed substrate 1.

At this retracted position, the ferrule F adhered and fixed to the tip of the optical cable 0C is inserted into the chuck 6 and clamped.

Next, a new command signal from the pressing force signal generator 402 (predetermined by experiments,
A pressing force that deforms the film 201 stretched on the polishing plate 210 so that a specified radius of curvature can be formed is generated and applied to the drive lines 400b to 400a of the bobbin 3 of the VCM via the power amplifier 401 to apply a constant pressure. Mechanism 50
0 is moved toward the polishing plate 210 and the tip of the ferrule F is abutted against the film 201.

As a result, the tip of the ferrule F is VCM
Is pushed into the film 201 to a position where the repulsive force due to elastic deformation of the film 201 is balanced.

Further, the polishing base 200 and the motor 7 are rotated, and the polishing agent 102 is further supplied to polish the end surface of the ferrule F into a convex spherical shape.

FIG. 6 is a schematic configuration diagram including a partial cross section showing a constant pressure polishing apparatus according to a second embodiment of the present invention.

In FIG. 6, 506 is a pressing force detector, and 403 is a drive controller.

The parts having the same numbers as those in the configuration diagram (FIG. 5) of the first embodiment have the same functions as those of the first embodiment.

The above-described structure operates as follows.

The constant pressure applying mechanism 500 chucks the ferrule F at the position indicated by the two-dot chain line in the drawing (hereinafter referred to as the retracted position).
Remove from.

In order to transfer the constant pressure applying mechanism 500 to the retracted position, the applied current is made to flow from the drive lines 400a to 400b of the VCM bobbin 3 via the current amplifier 401 by the command signal from the pressing force signal generator 402. The attachment substrate 4 is abutted against the stopper 1a attached to the fixed substrate 1.

At this retracted position, the ferrule F adhered and fixed to the tip of the optical cable 0c is inserted into the chuck 6 and clamped.

Next, a new command signal from the pressing force signal generator 402 (predetermined by experiments,
A pressing force for deforming the film 201 so that a prescribed radius of curvature can be formed is generated and applied to the driving lines 400b to 400a of the bobbin 3 of the VCM via the power amplifier 401, and the constant pressure applying mechanism 500 is applied to the polishing plate 210. And the tip of the ferrule F is abutted against the film 201.

As a result, the tip of the ferrule F is VCM
Is pushed into the film 201 to a position where the repulsive force due to elastic deformation of the film 201 is balanced.

This pressing force is detected by the pressing force detector 506.
The detection signal detected by and output via the signal line 507 is compared with the command amount from the pressing force signal generator 402 by the drive controller 403.

At this time, the tension fluctuation of the optical cable 0c and VC
When a normal pressing force is not applied to the film 201 due to a change in the current-force characteristic of M or the like, the fluctuation force (the value detected by the pressing force detector 506 from the command value of the pressing force signal generator 402). Is calculated by the drive controller 403, and the calculated signal value (correction force of pressing force) is power-amplified by the power amplifier 401 to correct the pressing force of VCM.

FIG. 7 shows a chuck 6 used in the second embodiment.
FIG. 7 is a cross-sectional view showing a specific example of a pressing force detector 506.

506 is a gear directly connected to the rotary motor 7,
Reference numeral 502 is a ball bearing for fastening the chuck rotation mechanism to the mounting substrate 4, 504 is a chuck holding mechanism in which a rotation gear is incorporated in a part of the outer periphery, and 506 is a pressing force detector.

In FIG. 7, the ferrule F to be polished is given a rotary motion by the rotary motor 7 and gears 501 and 503.

In order to detect the ferrule pressing force at the time of polishing, a pressing force detector 506 is adhesively fixed so as to be inscribed in the chuck holding mechanism 504 and externally in contact with the chuck 6.

With such a structure, the pressing force of the ferrule F against the film 201 can be detected even when the chuck 6 is rotated, and this detection signal is taken out via the signal line 507. .

FIG. 8 shows a specific example of the pressing force detector 506.

FIG. 8A shows a concrete example in which a cylindrical piezo element is used as a detection element, and 510 is a cylindrical piezo element.
511a is an inner conductor and 511b is an outer conductor.

In FIG. 8A, when the pressing force T acts from the left end of the cylindrical piezo element 510 whose right end is fixed in the figure, a voltage substantially proportional to the pressing force is generated on the inner and outer surfaces of the cylindrical piezo element 510.

This generated voltage is detected by the detection lines 511a and 511b.
It can be taken out to the outside via a sensor (for more detailed detection mechanism, see Kenji Uchino, Piezoelectric / electrostrictive actuator, Morikita Publishing Co., Ltd., page 101).

FIG. 8B shows a second specific example of the pressing force detector 506, which is a specific example using a strain gauge as a detection element.

In FIG. 8B, 512 is a circular tube, 51
Reference numeral 3 is a first strain gauge element, and 514 is a second strain gauge element.

In this embodiment, third and fourth strain gauge elements 515 and 516 (not shown) are bonded to the first and second cylinders 512 at positions symmetrical with respect to the central axis of the cylinder 512. FIG. 9 shows a detection circuit used in the second specific example.

In FIG. 9, 520 to 523 are strain gauge amplifier circuits corresponding to the respective strain gauge elements, and 524 is 4
It is an input sum circuit.

In FIGS. 8 (b) and 9, 513a, 5
13b to 516a and 516b are the gauge elements 513.
˜516 detection lines.

That is, in FIG. 8B, when the pressing force T acts from the left end of the circular pipe 512 whose right end is fixed in the figure, the circular pipe 512 contracts by a slight amount due to the compression force.

The amount of shrinkage is four strain gauges 513-5.
Since these four strain gauge output signals can be detected by the strain gauge 16, the strain gauge amplifier circuit 520 corresponding to each strain gauge
~ 523, after amplifying each amplified signal, a 4-input sum circuit 52
4 and the voltage proportional to the pressing force is detected from the sum signal value.

In the second specific example of the pressing force detector 500, the pressing force is detected by the sum signal of the four strain gauges.

Therefore, even if a force other than the axial force, such as a tilting force, is generated in the cylinder of this detector, the distortion between the circles due to this tilting force extends to the central axis and becomes a contraction distortion. It is characterized in that it is not canceled between one set of strain gauges and the falling force is not erroneously detected as a pressing force.

As described above, in the first and second embodiments of the present invention, since the polishing pressure is generated by using the VCM, the ferrule tip is located at any position within the movable stroke range of the bobbin 3. Even if it hits the film 201, a constant force can be obtained, so that polishing with a constant radius of curvature can be performed even if there is a length error of the ferrule F or a positional deviation due to the chuck.

As an example, when a large number of pieces were polished in Conventional Example 2, the variation in the radius of curvature could be accurately polished to within ± 1 mm with respect to the set value.

On the other hand, V is detected by the pressing force detection signal.
In the second embodiment for controlling the drive of the CM, it is possible to detect and correct the pressing force variation due to the optical cord tension and the frictional force of the linear guide mechanism for the mounting substrate, which is suitable for precision polishing of an optical ferrule for analog optical communication. It can realize a polishing machine.

As described above, in the constant pressure polishing apparatus according to the first and second embodiments of the present invention, the ferrule is fixed to the movable bobbin of the VCM so that a constant polishing pressure can be given by the VCM output. It has the following advantages.

(1) Since polishing can be performed at a constant pressure without being influenced by the length of the ferrule and chuck error,
It becomes possible to polish a convex spherical surface with good reproducibility and little variation.

(2) Since the polishing pressure can be controlled only by changing the applied current, it is not necessary to replace the mechanical parts as in the case of changing the conventional radius of curvature, and an arbitrary radius of curvature can be easily obtained. it can.

(3) Since the ferrule can be moved and the polishing pressure can be applied by electric control, the device structure is suitable for automation of polishing.

(4) Further, in the second embodiment in which the VCM is drive-controlled by the pressing force detection signal,
Since it is possible to detect and correct the pressing force fluctuation due to the optical cable tension and the frictional force of the linear guide mechanism for the mounting substrate, it is possible to realize a polishing machine suitable for precision polishing for analog optical communication.

[0077]

As described above, according to the present invention, therefore, it is possible to provide a constant pressure polishing apparatus which has good workability and can polish the ferrule end face with high reproducibility and high precision. Become.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a conventional polishing machine.

FIG. 2 is a cross-sectional view showing another example of a conventional polishing machine.

FIG. 3 is a sectional view showing another example of a conventional polishing machine.

FIG. 4 is a diagram showing a relationship between a pressing amount of a ferrule into a film and a radius of curvature.

FIG. 5 is a schematic cross-sectional view showing a first embodiment of a constant pressure polishing apparatus of the present invention.

FIG. 6 is a schematic sectional view showing a second embodiment of the constant pressure polishing apparatus of the present invention.

FIG. 7 is a schematic sectional view showing a specific example of a chuck in a second embodiment of the constant pressure polishing apparatus of the present invention.

FIG. 8 is a schematic view showing first and second specific examples of the pressing force detector in the second embodiment of the constant pressure polishing apparatus of the present invention.

FIG. 9 is a diagram showing a detection circuit when a pressing force detector according to a second specific example of the second embodiment of the constant pressure polishing apparatus of the present invention is used.

[Explanation of symbols]

F ...... Ferrule, L ...... Ferrule length, 0c ...... Optical fiber, 1 ...... Fixed board, 1a ...... Stopper, 2 ...... Magnetic circuit, 3 ...... Bobbin, 4 ...... Mounting board, 5 ...... Straight line Guide mechanism, 6 ... Chuck, 7 ... Motor, 100 ... Polishing surface plate, 100a ... Polishing surface, 101 ... Ferrule holder, 102 ... Abrasive, 200 ... Polishing base, 201 ... Film, 202 ... Butting block, 300 ... Polishing board, 301 ... Elastic body, 302 ... Polishing sheet, 303 ... Spring, 401 ... Current amplification circuit, 402 ... Pressing force signal generator, 403 ... Drive Control circuit, 501 ... Rotation motor gear, 502 ... Rotation guide mechanism, 503 ... Chuck part gear, 504 ... Chuck holding mechanism, 506 ... Pressing force detector, 507 ... Pressing force detection signal line, 510 ... Cylindrical piezo element, 511a, 511b ... Cylindrical piezo output line, 512 ... Circular tube, 513 ... First strain gauge, 514 -516 ... 2nd strain gauge-4th strain gauge, 520-523 ... 1st strain gauge amplifier-4th strain gauge amplifier, 524 ... 4 input sum circuit, 210 ... Polishing board, 500 ...... Constant pressure application mechanism section.

Claims (2)

[Claims] 1. An end-face polishing apparatus for an optical connector ferrule, which relatively moves an optical connector ferrule and a polishing disc, to polish the end face polishing device at an opposite position to the polishing disc by an electric signal.
A rectilinear drive mechanism that is movable in the axial direction of the optical connector ferrule, and a chuck that is driven by the rectilinear drive mechanism and that grips the optical connector ferrule and rotates the chuck around the axis of the optical connector ferrule. A constant pressure polishing apparatus comprising: a constant pressure imparting mechanism section including a chuck rotation driving mechanism that is driven; and a pressing force signal generator that supplies the electric signal to the rectilinear driving mechanism. 2. The constant pressure polishing apparatus according to claim 1, further comprising a pressing force detector that is provided in association with the constant pressure applying mechanism section and that detects a force for pressing the optical connector ferrule against the polishing plate. And a drive controller that calculates a drive amount of the linear drive mechanism in accordance with a pressing force detection signal from the pressing force detector and an electric signal from the pressing force signal generator. The constant pressure polishing apparatus according to 1.