JP2000028858A - Ferrule for optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule capable of aligning the vertex of a spherical surface and a fiber. SOLUTION: This ferrule for an optical connector consists of a fine hole 5 which is opened at the center of a columnar ferrule 1, the spherical surface 3 which is formed at the front end of the ferrule 1 in such a manner that a slope 14 inclined with a line G orthogonal with the axial center 5a of the fine hole 5 is formed as a base and its vertex 4 intersects with the axial center 5a and convergent tapered surfaces 2, 2 which are extended to the skirts 7, 8 of the spherical surface 3 from the outer peripheral surface 1a of the ferrule 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a ferrule for an optical connector.

[0002]

2. Description of the Related Art Optical fibers are connected by optical connectors.
FIG. 9 is a cut-away view of a ceramic ferrule. A ceramic ferrule is formed into a cylindrical shape and fired is called a ceramic ferrule 100 (hereinafter abbreviated as "ferrule"). A hole 101 for fixing through the hole is opened, and a flange 102 made of metal or the like is provided. Connection is spherical surface 10 at the tip
This is performed by abutting the three, but the light is
Is reflected slightly but causes connection loss.

In order to prevent the loss due to reflection, Japanese Patent Application Laid-Open No. 63-279205 and Japanese Patent Application Laid-Open No.
No. 05 proposes a ferrule having an inclined end. 10 (a) to 10 (c) are explanatory views of a conventional method of processing an inclined surface type ferrule. JP-A-1-121
No. 805 describes that (c) is cut out from (a) using a polishing jig, but (b) is generally mediated.

[0004] That is, in (a), the tip of the ferrule 201 is a surface perpendicular to the fiber 202. Therefore, the tip is cut at an angle θ in FIG. Next, the cut surface 201a is polished to obtain a spherical surface 201b. This (c) corresponds to the tip shape of the ferrule disclosed in JP-A-63-279205 and JP-A-1-121805.

[0005]

FIG. 11 shows FIG. 10 (c).
The spherical surface 201b is formed with the cut surface 201a as a tangent line. As a result, the vertex 201c of the spherical surface is connected to the intersection with a line drawn at an angle θ from the center of the fiber 202. The vertex 201c is shifted from the fiber 202 by the dimension δ. If the ferrules whose vertices are displaced from each other are abutted, the adhesion will naturally deteriorate and a connection loss will occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ferrule that can match the apex of a spherical surface with a fiber.

[0007]

In order to achieve the above object, a first aspect of the present invention is to provide a cylindrical ferrule having a fine hole formed at the center thereof and a slanted line inclined with respect to a line perpendicular to the axis of the fine hole. The ferrule for an optical connector includes a spherical surface formed at the tip of the ferrule such that the surface has a bottom surface and a vertex intersects the axis, and a tapered tapered surface extending from the outer peripheral surface of the ferrule to the skirt of the spherical surface. The displacement between the apex of the spherical surface and the fiber can be reduced, and the connection loss at the butted portion between the ferrules can be reduced. By joining ferrules whose vertices match each other, connection loss can be further reduced.

A second aspect of the present invention is a ferrule for an optical connector, comprising: a spherical surface formed at a tip of a cylindrical ferrule; and a tapered tapered surface extending from an outer peripheral surface of the ferrule to a skirt of the spherical surface. The intersection of is the reference contact point, the straight line passing through this reference contact point and inclined with respect to the center of the ferrule is the reference normal perpendicular to the spherical surface, and the taper tapered in the longitudinal section of the center of the ferrule including this reference normal When the taper center line of the surface is determined and the contact straight line perpendicular to the reference normal and the reference contact point is defined in the longitudinal section, the center of the line segment formed by the tapered tapered surface is defined as the ferrule. Characterized in that the position of the tapered tapered surface is determined so as to match the center of the tapered surface. By connecting ferrules whose vertices match, connection loss can be reduced.

A third aspect of the present invention provides a fine hole formed at the center of a cylindrical ferrule, a spherical surface formed at the tip of the ferrule with an inclined surface inclined with respect to a line perpendicular to the axis of the fine hole as a bottom surface, An optical connector ferrule comprising a tapered tapered surface extending from an outer peripheral surface of the ferrule to a spherical hem,
A ferrule for an optical connector, wherein a taper center line of a tapered tapered surface is eccentric from an axis of a pore so that an apex of a spherical surface is close to an axis of the pore. When the ferrule is machined, the ferrule can be mounted in parallel with the center of rotation, so that the mounting structure of the chuck is simplified.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a ferrule manufactured by the method of the present invention.
A tapered tapered surface 2 is first formed at the tip of the ferrule (hereinafter abbreviated as "ferrule"), and a spherical surface 3 is formed at the tip thereof.
The feature is that the vertex 4 coincides with the axis (axis) 5 a of the pore 5.

The taper angles α, α are determined by the following geometrical explanation. Draw a spherical surface 3 passing through the vertex 4 (the spherical radius R is known), define intersections 7 and 8 with the chord 6, and define these intersections 7 and 8
May be drawn (corresponding to the isosceles sides of an isosceles triangle). As a result, the tapered surface 2 in the upper part of the figure is (α + θ) with respect to the pores 5 and that in the lower part is (α−θ).

A processing method for obtaining a ferrule having the above shape will be described below. FIGS. 2A to 2D are explanatory views of a processing method according to the method of the present invention. First, in FIG. 2A, a ferrule 1 having a front end perpendicular to a pore axis is tapered in FIG. The tapering method will be described later in detail.

At (c), an inclined surface 14 having an inclination angle θ is formed at the tip. At this time, since the processing center coincides with the pore 5, the vertex 4 of the spherical surface 3 is formed at the same position as the pore. In (d), spherical processing is performed. (D) is the same as FIG.

FIGS. 3 (a) to 3 (d) are views for explaining a processing method according to another method of the present invention. First, in FIG. 3 (b), an inclined surface 14 is formed at the tip, and thereafter, in FIG. The result is the same as that of FIG. 2 (d).

FIG. 4 is a principle view of a processing apparatus suitable for carrying out the method of the present invention. The processing apparatus 20 includes a chuck 21 for gripping and fixing the ferrule 1 to a rotating spindle (not shown), and a tip side of the ferrule. And a polishing machine 22 for polishing. The ferrule 1 has a rotation center 21 of the chuck 21.
a with respect to a.

The ferrule 1 corresponds to FIGS. 2 (a) to 2 (d).
First, (a) the ferrule 1 whose tip is a plane perpendicular to the pore axis is gripped by the chuck 21,
(B) Taper processing is performed by the polishing machine 22 while rotating, (c) the inclined surface 14 is formed, and (d) the inclined surface 14 is formed.
In this case, a point at which the rotation center 21a and the axis 5a of the fine hole 5 coincide with each other is processed as a vertex 4 to form a spherical surface. This is shown in FIG.
A processing procedure according to another method according to (a) to (d) may be used.

FIG. 5 is a principle diagram (part 1) of the ferrule according to the present invention, and shows the ferrule 1 which is combined with the contents of FIGS. 1 to 4 and is reprinted based on the description. In this figure, the definition is as follows. The intersection of the oblique line 11 and the oblique line 12 is A, the intersection of the oblique line 11 and the inclined surface 14 is B, the intersection of the oblique line 12 and the inclined surface 14 is C, the vertex 4 is D, and the outer peripheral surface of the ferrule 1 is 1a, an extension line of the outer peripheral surface 1a is a line E, an intersection of the line E and the oblique line 12 is F, a line (orthogonal line) orthogonal to the axis 5a is G, and the intersection G is parallel to the line G. The line is H, the intersection of the line H and the line E is I, and the intersection of the inclined surface 14 and the line E is J.

△ CFI is a right triangle, and ∠CFI is (α-θ). Therefore, ∠FCI, that is, ∠a, is a = 90 ゜-(α-θ) (1). Also, △ JCI is a right triangle, and ∠JCI
Is θ. Therefore, ∠FCJ, that is, ∠b, is b = a−θ = (90 ° − (α−θ)) − θ = 90 ° −α (2) Furthermore, since ∠ACD, that is, ∠c is the diagonal of ∠b, (90 ゜ -α). Therefore, when △ ADC is considered, ∠ADC, that is, ∠d is d = 180 ゜-(90 ゜ -α) -α = 90 ゜ (3). Therefore, △ ADC is a right triangle. by the way,
The side K of the ADC (the line segment K between the point A and the point D) is ΔA
It is also the side K of DB. Moreover, ∠CAD = ∠BAD, ∠
ADC = {ADB = 90}. Therefore, {ADC and △
It is joint with ADB. Therefore, △ ABC is an isosceles triangle.

FIG. 6 is a diagram (part 2) of the principle of the ferrule according to the present invention, and is a diagram in which the contents of FIG. 5 are arranged. Since ΔABC is an isosceles triangle, the bisector K (line segment K) of the apex angle e vertically bisects the base BC. Therefore, BD = DC, that is, L1 = L2. As is clear from the above description, according to the present invention, the tip of the ferrule 1 having the pore 5 in the center is formed into a tapered surface 2 or 2 and the tip of the ferrule 1 is formed into a plane G perpendicular to the axis of the pore 5. The spherical surface 3 is formed with an inclined surface (inclined surface 14).
a.

That is, the columnar ferrule 1 has a bottom surface formed by a hole 5 opened at the center thereof and an inclined surface 14 inclined with respect to a line G perpendicular to the axis 5a of the hole 5.
3 is formed at the tip of the ferrule 1 so that the spherical surface 3 intersects the axis 5a.
Tapered surfaces 2 and 2 extending to the hem (intersections 7 and 8) of
Consists of

In other words, the cylindrical ferrule 1 has a spherical surface 3 formed at the tip thereof and an outer peripheral surface 1 a of the ferrule 1.
From the center of the ferrule 1 (the axis 5a of the pore 5) and the spherical surface 3 as a reference contact point D, A straight line passing through the reference abutment point D and inclined with respect to the center of the ferrule 1 is defined as a reference normal M orthogonal to the spherical surface 3 and in a vertical cross section of the center of the ferrule 1 including the reference normal M (shown in FIG. A taper center line (a line passing through the line segment AD) of the tapered tapered surfaces 2 and 2 is defined in the cross section, and a contact straight line 14 (inclined surface 14) orthogonal to the reference normal M and the reference contact point D in the vertical cross section. That is, when the tangent of the spherical surface 3 at the reference contact point D) is determined, the center of a line segment BC formed by the contact straight line 14 being surrounded by the tapered tapered surfaces 2 is aligned with the center of the ferrule 1. The positions of the tapered surfaces 2 and 2 are determined.

FIG. 7 is a principle view of another processing apparatus for carrying out the method of the present invention.
Are mounted eccentrically by a distance m with respect to the rotation center 31a of the chuck 31. 32 is a polishing machine. In this case, the inclination angle θ of the inclined surface 14 and the spherical radius R of the spherical surface 3
In consideration of (see FIG. 1), the distance m is determined so that the spherical surface and the axis 5a of the pore 5 are close to each other. FIG. 4 above
Since the ferrule 1 is mounted in parallel with the rotation center 31a, the mounting structure of the chuck 31 is simplified as compared with the case where the processing device 20 is used.

FIG. 8 is a diagram (part 3) of the principle of the ferrule according to the present invention, which shows the ferrule which is combined with the contents of FIGS. 1 and 7 and reproduced again based on the description. The cylindrical ferrule 1 has a pore 5 opened at the center thereof and a line G orthogonal to the axis 5 a of the pore 5.
The spherical surface 3 formed at the tip of the ferrule 1 with the inclined surface 14 inclined with respect to the bottom as the bottom surface, and the tapered tapered surfaces 2 and 2 extending from the outer peripheral surface 1a of the ferrule 1 to the hem (intersections 7 and 8) of the spherical surface 3 And the vertex 4 of the spherical surface 3
The taper center lines (rotation center 31a) of the tapered tapered surfaces 2 and 2 are eccentric from the axis 5a of the fine hole 5 so that are close to each other.

The tapering of the taper is not limited to polishing, but may be formed integrally with the tip of the ferrule 1 by injection molding or press molding.

[0025]

According to the present invention, the following effects are exhibited by the above configuration. The first aspect of the present invention provides a ferrule having a pore formed in the center of a columnar ferrule, and an inclined surface inclined with respect to a line perpendicular to the axis of the pore as a bottom surface, and a vertex intersects the axis. Since the ferrule for an optical connector consists of a spherical surface formed at the tip and a tapered tapered surface extending from the outer peripheral surface of the ferrule to the skirt of the spherical surface, it is possible to reduce the positional deviation between the apex of the spherical surface and the fiber. Connection loss at the abutting portion of the two can be reduced. By joining ferrules whose vertices match each other, connection loss can be further reduced.

A second aspect of the present invention is a ferrule for an optical connector, comprising: a spherical surface formed at a tip of a cylindrical ferrule; and a tapered tapered surface extending from an outer peripheral surface of the ferrule to a skirt of the spherical surface. The intersection of is the reference contact point, the straight line passing through this reference contact point and inclined with respect to the center of the ferrule is the reference normal perpendicular to the spherical surface, and the taper tapered in the longitudinal section of the center of the ferrule including this reference normal When the taper center line of the surface is determined and the contact straight line perpendicular to the reference normal and the reference contact point is defined in the longitudinal section, the center of the line segment formed by the tapered tapered surface is defined as the ferrule. Since the position of the tapered tapered surface is determined so as to match the center of the ferrule, the connection loss can be reduced by abutting the ferrules whose vertices match.

[0027] A third aspect of the present invention provides a fine hole formed at the center of a cylindrical ferrule, a spherical surface formed at the tip of the ferrule with an inclined surface as a bottom surface inclined with respect to a line perpendicular to the axis of the fine hole, An optical connector ferrule comprising a tapered tapered surface extending from an outer peripheral surface of the ferrule to a spherical hem,
Since the taper center line of the tapered tapered surface is decentered from the axis of the pore so that the vertex of the spherical surface is close to the axis of the pore,
When the ferrule is machined, the ferrule can be mounted in parallel with the center of rotation, so that the mounting structure of the chuck is simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a ferrule manufactured by the method of the present invention.

FIG. 2 is an explanatory view of a processing method according to the method of the present invention.

FIG. 3 is an explanatory view of a processing method according to another method of the present invention.

FIG. 4 is a diagram showing the principle of a processing apparatus for performing the method of the present invention.

FIG. 5 is a principle diagram of a ferrule according to the present invention (part 1).

FIG. 6 is a principle diagram of a ferrule according to the present invention (part 2).

FIG. 7 is a principle diagram of another processing apparatus for performing the method of the present invention.

FIG. 8 is a principle diagram of a ferrule according to the present invention (part 3).

FIG. 9 is a cutaway view of a ceramic ferrule.

FIG. 10 is an explanatory view of a conventional method for processing an inclined surface type ferrule.

11 is an enlarged sectional view of a ferrule according to the processing method of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ferrule, 1a ... Outer peripheral surface, 2 ... Tapered taper surface,
3 ... spherical surface, 4 ... vertex, 5 ... pore, 5a ... pore center,
7, 8: skirt of spherical surface (intersection), 14: inclined surface, M: reference normal.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Moriyuki Fujitake 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Tochiki Kiki Co., Ltd. 2-1-1 Nakajima Totoki Kiki Co., Ltd.

Claims (3)

[Claims] 1. A bottom surface having a pore formed in the center of a columnar ferrule and an inclined surface inclined with respect to a line perpendicular to the axis of the pore, wherein a vertex intersects the axis. An optical connector ferrule comprising: a spherical surface formed at a tip of a ferrule; and a tapered tapered surface extending from an outer peripheral surface of the ferrule to a skirt of the spherical surface. 2. A ferrule for an optical connector comprising: a spherical surface formed at a tip of a cylindrical ferrule; and a tapered tapered surface extending from an outer peripheral surface of the ferrule to a skirt of the spherical surface. Is defined as a reference contact point, and a straight line passing through the reference contact point and inclined with respect to the center of the ferrule is defined as a reference normal perpendicular to the spherical surface.
When a taper center line of the tapered taper surface is defined in a vertical section at the center of the ferrule including the reference normal, and a contact straight line orthogonal to the reference normal and the reference contact point is defined in the vertical section, this contact A ferrule for an optical connector, characterized in that the position of a tapered tapered surface is determined so that the center of a line formed by a straight line surrounded by the tapered tapered surface coincides with the center of the ferrule. 3. A fine hole formed at the center of a cylindrical ferrule, a spherical surface formed at the tip of the ferrule with an inclined surface inclined with respect to a line perpendicular to the axis of the fine hole as a bottom surface,
An optical connector ferrule comprising an outer peripheral surface of the ferrule and a tapered tapered surface extending to a skirt of a spherical surface, such that a vertex of the spherical surface is close to an axial center of the fine hole. A ferrule for an optical connector, wherein a taper center line of a tapered tapered surface is eccentric.