JP3288529B2 - Diamond polishing film for polishing end face of optical fiber connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for polishing an end face of an optical fiber connector which has no step between a quartz optical fiber and a zirconia ferrule and has improved optical characteristics, particularly a return loss, in the finish polishing for the end face of an optical fiber connector. A diamond polishing film.

[0002]

2. Description of the Related Art Conventionally, in an optical transmission line, an optical connector using a zirconia ceramic ferrule has been used for connecting the optical connector. This optical fiber connector has an end face having a radius of curvature of 10 to 25 mm, and can be connected to each other without gaps to reduce connection loss and return loss at a connection portion. I have. Conventionally, zirconia sera
Optical connector consisting of mixed ferrule and quartz fiber
For polishing diamond finish film on the end face of
Is, 1 [mu] m diamond mean particle size d _50, Sutifune
Value ET ³ is 5.4 × 10 ⁷ kgf / cm ² (μm) ³ , center line
Polished film with average surface roughness Ra of 0.3μm is used
Have been.

[0003]

However, when considering the introduction of high-performance transmission systems such as video-based analog transmission and high-speed digital transmission, the order of one digit or more, that is, 40 bits or more, is required.
A high-performance connector having a return loss of not less than db has been required. In order to realize this high-performance connector, it is further required that the end face of the connector has high precision and high quality. As described above, conventionally, a diamond polishing film for finish polishing the end face of an optical connector composed of a zirconia ceramic ferrule and a quartz fiber has a diamond average particle diameter d ₅₀ of 1 μm and a stiffness value ET ³ of 5.4 × 10 ⁷ kgf / cm. ([mu] m) ^3, but the center line average surface roughness Ra is used polishing films of 0.3 [mu] m, however, when using the polishing film, diamond particle size, due to the stiffness value and surface roughness, etc. There is a problem that high-quality polishing cannot be performed because scratches occur. Also,
Polishing film with extremely small average particle diameter, stiffness value, surface roughness, etc. of diamond particles does not have enough polishing power to remove scratches and processing strain generated by pre-treatment such as rough polishing, so it is necessary for finish polishing. Becomes unsuitable for use. That is, (1) a polishing film having a large particle diameter leaves a scratch or a large processing strain locally when acting on a fiber processing surface; Since the roughness and the processing distortion cannot be removed, the result is that it is unsuitable for finish polishing of the end face of the optical fiber connector. From this, the return loss is 20 to 30
In an optical connector of dB, light is reflected at a boundary layer having a different refractive index and becomes return light, causing noise of an optical signal,
There are problems such as adverse effects on light sources such as semiconductors.

The present invention has been made in view of such a problem, and when the above-mentioned polishing film is used, local scratches and processing distortion on the fiber surface and reduction in polishing power are reduced. An object of the present invention is to provide a diamond polishing film for polishing an end face of an optical fiber connector, which has solved the problems at the same time.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention as defined in claim 1 is constituted, and the present invention provides a method for polishing the end face of an optical fiber connector , which comprises the steps of: Roughness,
When the end face of an optical fiber connector is polished by controlling the diamond particle diameter, the diamond polished film can maintain high-performance polishing without generating scratches and processing strain on the fiber surface, and has a return loss of 40 dB or more. Wherein the optical fiber connector is obtained.

In a diamond polished film using a plastic film as a support, a stiffness value (ET ³ ) used as an index of the flexibility of the polished film is defined as T being the total height of the polished film and E being Young's modulus.
Is 3.75 × 10 ⁷ ± 0.75 × 10 ⁷ kgf / cm ²
(Μm) ³ , diamond average particle diameter (d ₅₀ ) is 0.1
0.75 μm, center line average surface roughness (R _a ) of 0.1
By using a diamond polishing film for polishing the end face of an optical fiber connector satisfying the range of ~ 0.25 µm, scratches and processing distortion can be suppressed on the fiber face, and high-performance polishing can be maintained. High-quality polishing with little processing distortion and high-efficiency polishing that can remove the surface roughness of the pre-processing can be easily obtained.

Further, the average diameter (d ₅₀ ) of the diamond particles of such a polishing film is 0.1 to 0.75 μm.
m, the center line average surface roughness (R _a ) of the film is 0.1 to
0.25 μm and a stiffness value (ET ³ ) of (3.0 to
4.5) × 10 ⁷ kgf / cm ² (μm) ³ and the end face polishing is optimal, but d ₅₀ is 0.1 μm or less and _Ra is 0.1
μm or less and ET ³ of 3.0 kgf / cm ² (μm)
^In the case of ³ or less, the polishing force of the end face of the optical fiber connector is greatly reduced, and the processing capability required for fiber polishing is significantly reduced. As described above, since scratches and processing distortion generated in the pre-processing cannot be removed, high-quality polishing cannot be obtained. On the other hand, d ₅₀ is 0.75 μm or more, _Ra is 0.25 μm or more, and ET ³ is 4.5 kgf / cm ^2.
(Μm) In the case of ³ or more, a deep scratch is generated on the end face of the optical fiber connector, and the surface roughness becomes large. As a result, a finishing diamond polishing film having high polishing quality cannot be obtained.

[0008]

Embodiments will be described below with reference to embodiments. (Example 1) Example 1 shows the relationship among the particle size, surface roughness and return loss of a polishing film. FIG.
1 shows a schematic explanatory view of a polishing apparatus used for the diamond polishing film of the present invention. An elastic body 2 having a thickness of about 2 to 3 mm is stuck on the polishing plate 1, a polishing film is fixed thereon, and the end face of the optical fiber connector is pressed against the surface with a load of 500 g or less. Rotating at 50-100 rpm, the fiber optic connector is polished by repeated movements in a figure eight locus. At this time, as the diamond abrasive grains, synthetic diamond having an average particle diameter d ₅₀ = 0.1 to 2.18 μm was used, and polyurethane (N2304 manufactured by Nippon Polyurethane Industry Co., Ltd.) and PVC-PVAc-PV were used as binder resins.
An abrasive paint was prepared using A resin (VAGH, manufactured by UCC), a polyisocyanate crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Industry) as a crosslinking agent, and a mixed system of MEK / toluene / cyclohexanone as a diluting solvent. Table 1 shows the formulations of the prepared polishing coatings. The above-mentioned polishing paint is applied on a support by a coating machine having various heads such as a Meyer bar, a gravure, a die, and a nozzle.
It was applied uniformly to a coating thickness of μm.

[0009]

[Table 1]

The polishing film coated with the polishing paint has a center line surface roughness _Ra of 0.1 to 0.47 μm and a stiffness value ET ³ of 4.24 × 10 ⁷ kgf / cm ² (μm).
m) Fixed to ³ .

The base material is not only polyethylene terephthalate (PET) but also polyethylene naphthalate (PEN), polyamide, polyimide, polycarbonate and a film obtained by treating them, polypropylene foamed butyl rubber, foamed neobrene, foamed soft polyethylene, Foamed synthetic rubber, other synthetic paper, nonwoven fabric, other metal foil, and the like can be used. As the binder resin, various thermoplastic resins and thermosetting resins can be used in addition to this embodiment. In this case, the thermoplastic resin is a vinyl chloride resin, a polyester resin, an alkyd polyolefin resin, a pure acrylic resin, a nitrocellulose resin, a nitrocellulose acrylic resin, a modified acrylic resin, or a rubber resin. Examples include urethane elastomer nitrile rubber, silicone rubber, ethylene vinyl acetate rubber, fluorine rubber, other water-soluble resins, various emulsion resins, and the like. Examples of the thermosetting resin include polyester polyol resins, epoxy or epoxy pendant acrylic resins and amine pendant acrylic resins, polyorganosiloxane resins, various UV curable resins and EB curable resins, and urethane-based oil resins. , Moisture-cured polyurethane resin, fluorine resin, etc. 100
It can be used at any time from a resin which undergoes a curing reaction at a temperature of not more than ° C.

The experimental procedure of the evaluation characteristics of the polishing film is as follows. First, the end face of the optical fiber connector is removed with an alumina-based polishing film to remove the adhesive of the fiber, the ferrule and the epoxy resin adhering to the connector end face. ~
Using a diamond polished film having a particle size of about 5 μm, rough processing was performed between the fiber and the ferrule into a substantially identical convex spherical shape, and this was used as a pretreatment sample in this experiment.

The polishing conditions are as follows. A polishing film is fixed on an elastic body having a thickness of about 5 mm adhered to a polishing plate of 50 mmφ, and the end face of the optical fiber connector of zirconia ferrule is polished on the surface with a polishing load of about 50 to 200 g. Pressing was performed, and the polishing machine was rotated at 100 rpm to perform polishing in about 2 minutes.

[0014] than this, the reflection attenuation amount of the polishing optical fiber connector, as a result of the measurement of the surface roughness, various particle size of the diamond abrasive film surface roughness R _a and the optical fiber connector which is polished by these polishing films Table 2 shows the measurement results of the return loss.

[0015]

[Table 2]

As a result, the diamond particle diameter and the surface roughness of the polishing film are such that the average particle diameter d ₅₀ = 0.1 to 0.1.
75 μm, center line average surface roughness _Ra = 0.1 to 0.25
It has been confirmed that a diamond polished film having a thickness of μm can obtain a high return loss of 40 dB or more.

On the other hand, the abrasive film has a diamond average particle diameter of 0.1 μm or less and a center line average surface roughness _Ra.
If it is 0.1 μm or less, it was confirmed that the polishing loss was not enough to remove the scratches and the deteriorated layer generated in the pretreatment, and the return loss was low. Further, when a polishing film having _a diamond particle diameter of 0.75 μm or more and a center line average surface roughness _Ra of 0.25 μm or more is used, a deep scratch or a deteriorated layer is generated on the end face of the fiber connector, and the return loss is reduced. It was confirmed that it became very small.

[0018] FIG. 2 is a diagram showing the effect of surface roughness R _a and the diamond-average particle size d ₅₀ of the polishing film on the reflection attenuation amount of the optical fiber connector.

Example 2 In Example 2, the return loss of the end face of the optical fiber connector by the diamond polishing film having various stiffness values is shown. By changing the polyurethane / PVC-PVA _C -PVA / polyisocyanate mixture ratio of the binder resin used in Example 1 was fabricated a polishing film having various stiffness values. From the results of Example 1, the average particle diameter d ₅₀ of the diamond particles was fixed at d ₅₀ = 0.38 μm. The application method and the polishing method were the same as those in Example 1, and the applied film was 10 μm, and only the effect of the stiffness value of the diamond polishing film was evaluated. In addition, a comparative experiment with a diamond polishing film conventionally used for polishing an end face of an optical fiber connector was also performed.

As a result, the stiffness value ET ³ is 3.7
5 × 10 ⁷ ± 0.75 × 10 ⁷ kgf / cm ² (μm) ³
The characteristics of the optical fiber connector polished with the polishing film in the range were such that the return loss was 40 dB or more, and it was confirmed that the final finish polishing of the high-quality optical fiber connector end face was possible.

On the other hand, the stiffness value ET ³ is 3.00 ×
In the case of 10 ⁷ kgf / cm ² (μm) ³ or less, the grinding force of the polishing film is inferior and the return loss is 40 dB or less, so that practical use is difficult. Conversely, the value of ET ³ is 4.5 × 10 ⁷ kg
In the case of f / cm ² (μm) ³ or more, it was confirmed that the stiffness of the polishing film was strong, the fiber was scratched, and the return loss was 38 dB or less. In this case, the return loss is too low to be practical. further,
A conventionally used diamond polishing film has a stiffness value ET ³ of 5.39 × 10 ⁷ kgf / cm ^2.
(Μm) ³ It was also confirmed that scratches were generated because the stiffness was too high. Table 3 shows the evaluation results of the stiffness value ET ³ , the center line average surface roughness _Ra , the polished state, and the return loss of the polishing films of the examples and the conventional polishing films.

[0022]

[Table 3]

FIG. 3 shows the results of Example 2 in which the relationship between the average surface roughness of the center line of the polishing film and the stiffness value is arranged. The polishing film for final finishing of the end face of the optical fiber connector has an average particle diameter (d ₅₀ ) of diamond particles of 0.38 μm, and a center line average surface roughness (R _a ) of the polishing film of 0.1 to 0.25 μm. And the stiffness value (E
T ³ ) is 3.75 × 10 ⁷ ± 0.75 × 10 ⁷ kgf / c
When it is within an appropriate region satisfying m ² (μm) ³ , a high-quality polished end surface free of polishing scratches such as scratches can be obtained. As a result, it was confirmed that polishing of a high-performance optical fiber connector having a return loss of 40 dB or more was sufficiently possible.

Example 3 Using a synthetic diamond particle having an average particle diameter d ₅₀ = 0.38 μm, the stiffness value ET ³ of the polishing film was 4.2.
With a constant value of 6 × 10 ⁷ kgf / cm ² (μm) ³ , the center line average surface roughness _Ra value of the polishing film is variously adjusted within a range of 0.06 to 0.5 μm depending on the coating dispersion conditions, coating conditions, and the like. did. The binder resin composition and the grinding test method used were the same as in Example 1, and the polishing accuracy was evaluated based on the presence or absence of scratches.

As a result, the center line average surface roughness _Ra = 0.
It was confirmed that scratches did not occur in the polishing film within the range of 1 to 0.25 μm, and high-precision polishing was possible. On the other hand, when the polishing film has _a surface roughness _Ra of 0.1 μm or less, the grinding power is inferior and the surface roughness cannot be removed in the pretreatment step. Conversely, when a polishing film having _{a Ra of} 0.25 μm or more is used, Deep scratches were generated, and it was confirmed that polishing accuracy was low in each case. Table 4 shows the above polishing results.

[0026]

[Table 4]

[0027]

According to the diamond polishing film for polishing the end face of the optical fiber connector of the present invention, since the polishing film has a predetermined diamond particle diameter, an average surface roughness of the center line of the film surface, and a stiffness value, High polishing power to remove scratches and damaged layers generated in the processing process.Also, diamond particles on the polishing film surface are uniformly distributed. Will not occur. As described above, there is an effect that a high-quality polished surface free from macro flaws and processing distortion having an optical characteristic after polishing and a return loss of the optical fiber connector of 40 dB or more can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a polishing measure used for a diamond polishing film of the present invention.

Figure 2 illustrates the effect sound of the surface roughness R _a and the diamond-average particle size d ₅₀ of the polishing film on the optical fiber connector return loss of the present invention.

FIG. 3 is a view showing the relationship between the center line average surface roughness _Ra and the stiffness value of the diamond polishing film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing board 2 Elastic body 3 Diamond polishing film 4 Optical fiber connector 5 Optical fiber 6 Ferrule

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tokumichi Kawashima 1-1-1, Taito, Taito-ku, Tokyo Inside Tokyo Magnetic Printing Co., Ltd. (72) Inventor Kazuya Orii 1-1-1, Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd. (56) References JP-A-4-8478 (JP, A) JP-A-63-185579 (JP, A) JP-A-3-277480 (JP, A) JP-A-4-101764 (JP, A) JP-A-1-240273 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24D 11/00 B24D 3/00 310

Claims (1)

(57) [Claims] 1. The diamond particles used have an average particle diameter (d ₅₀ ) in the range of 0.1 to 0.75 μm and a center line average surface roughness (R _a ) of the film surface in the range of 0.1 to 0.25 μm. And the stiffness value (ET ³ ), which is an index of the flexibility of the polishing film, defined as T and the Young's modulus of the polishing film is 3.75 × 10 ⁷ ± 0.
A diamond polishing film for polishing an end face of an optical fiber connector , characterized by satisfying a range of 75 × 10 ⁷ kgf / cm ² (μm) ³ .