JPH10245236A - Preliminary glass molded product and production of member for fixing optical fiber with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to mold even a thin plate-like molded product in high precision by satisfying such conditions that the inner side surfaces of a cylinder having a specific shape are brought into point or surface contact with the side surfaces of a preliminary glass molded product, when it is assumed that the preliminary glass molded product is inserted into the cylinder. SOLUTION: This preliminary glass molded product is a columnar article having a polygonal cross-sectional shape in the diameter direction, a shape surrounded with two or more conical curves or a shape surrounded with one or more straight lines and one or more conical curves, and satisfies either of conditions (i)-(iii). (i) When it is assumed that the preliminary glass molded product is inserted into a cylinder having the same height as the preliminary glass molded product, a rectangular cross-sectional frame shape in the diameter direction, and four inner side surface sizes each capable of being brought into contact with the side surfaces or edges of the preliminary glass molded product, one or more inner side surfaces of the cylinder and brought into line contact with the side surfaces of the preliminary glass molded product. (ii) One or more inner side surfaces of the cylinder are brought into line contact with the side surface edges of the preliminary glass molded product. (iii) The four inner side surfaces of the cylinder are brought into surface contact with the side surfaces of the preliminary glass molded product, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass forming preform used for obtaining a glass molded product and a method for manufacturing an optical fiber fixing member using the glass forming preform.

[0002]

2. Description of the Related Art In order to transmit and receive and relay light, optical fibers or optical fibers and optical components (for example, light emitting elements such as semiconductor lasers and light emitting diodes, light receiving elements such as photodiodes, microlenses, wave plates, It is necessary to optically connect an optical element such as a thin plate filter, an optical amplifier, an optical waveguide, etc. (hereinafter, “optically connecting” is referred to as “optical connection”), but it is used for optical communication and the like. The optical fiber to be used is generally a thin glass fiber. For example, a silica-based single mode optical fiber used for long-distance optical communication has a core having an outer diameter of about 10 μm and a cladding having an outer diameter of 125 μm covering the core. And is constituted by. Therefore, for example, when optically connecting the silica-based single-mode optical fibers to each other, or when optically connecting the silica-based single-mode optical fiber to the silica-based single-mode optical waveguide, the optical axis is shifted at the optical connection portion. To reduce the connection loss (for example, to 0.1 dB or less)
High alignment accuracy is required in which the amount of deviation of the optical axis is within about ± 1 μm.

Therefore, when optically connecting an optical fiber to another optical fiber or an optical component, the optical fiber is first fixed in advance by an optical fiber fixture such as an optical connector or an optical fiber array. A desired optical connection is made by active alignment or passive alignment. Here, the optical fiber array means a desired length exposed from one end of an optical transmission medium such as an optical fiber cord (single-core) or a tape fiber (multi-core) in which an optical fiber is protected by a covering portion made of resin or the like. A thin plate having an optical fiber fixing engagement portion for fixing (positioning) the made optical fiber (the maximum thickness is approximately 5
mm) and a thin plate (maximum thickness is generally 3 mm or less) for pressing and fixing the optical fiber engaged with the optical fiber fixing engagement portion.
And at least a holding block comprising:

The above-mentioned optical fiber guide block has only an optical fiber fixing engaging portion, an end on the side where the optical fiber is exposed in the optical transmission medium, in addition to the optical fiber fixing engaging portion. It can be roughly classified into those having a pedestal portion for fixing the portion together with the covering portion. on the other hand,
The above-described holding block is only for pressing and fixing the optical fiber engaged with the optical fiber fixing engaging portion of the optical fiber guide block (hereinafter, this holding block is referred to as an “optical fiber holding block”). An optical transmission medium fixed to the pedestal portion of the optical fiber guide block only for pressing and fixing the covering portion together with the covering portion (hereinafter, this holding block is referred to as a "holding block for the covering portion"), and an optical fiber presser. It can be broadly classified into a block having both functions of a block and a covering section holding block (hereinafter, this holding block is referred to as a “double-use holding block”).

The above passive alignment is a method of performing alignment (optical connection) only by mechanical positioning of optical fiber fixtures or optical fiber fixtures and optical components, and is easier to operate than active alignment. In recent years, it has been more suitably used because of the short time required. Mechanical positioning in passive alignment is performed using the bottom surface or side surface of the optical fiber fixture as a reference plane, or using an alignment mark provided at a desired position of the optical fiber fixture. In the passive alignment, a guide pin engaging portion is provided at a desired position of each of the two optical fibers to be optically connected (the optical fiber fixing devices or the optical fiber fixing device and the optical component) with high positional accuracy. It can also be performed by connecting these optical fiber fixtures or between the optical fiber fixture and the optical component.

An optical fiber fixture used for optically connecting an optical fiber to another optical fiber or an optical component has conventionally been a member made of glass, ceramics, silicon, resin, or the like (hereinafter referred to as an "optical fiber fixing member"). In recent years, a glass optical fiber fixing member has been suitably used for the following reasons. That is, when the optical fiber guide block and the holding block are fixed, or when the optical fiber array is connected to another optical fiber array or an optical component, fixing by an adhesive, fixing by soldering, and anode Although methods such as bonding and heat bonding have been adopted, it has been desired in recent years to use an ultraviolet-curable adhesive for reasons such as good workability. As a material, glass having good ultraviolet transmittance has been suitably used.

[0007] Among the optical fiber fixing members made of glass, an optical fiber guide block which requires a high dimensional accuracy for an optical fiber fixing engaging portion for fixing an optical fiber has conventionally been a glass block or the like. Is machined using a dicing saw, a diamond grindstone or the like.

By the way, in order to perform passive alignment using the bottom surface or side surface of the optical fiber fixture as a reference surface, it is necessary to increase the dimensional accuracy of the optical fiber fixing engagement portion in the optical fiber fixture. In addition, the positional accuracy of the optical fiber fixing engagement portion measured with reference to the bottom surface or the side surface of the optical fiber fixing device is set to be 1/1 / the value of the core diameter of the optical fiber to be optically connected by the optical fiber fixing device. It is desired to improve the accuracy to about 10 or less. In addition, in order to perform passive alignment using the alignment mark, in addition to increasing the dimensional accuracy of the optical fiber fixing engaging portion of the optical fiber fixing device, alignment with the optical fiber fixing engaging portion is performed. The position accuracy of the mark is set to be 1/10 of the value of the core diameter of the optical fiber used for optical connection by the optical fiber fixture.
It is desired to be within the range. In order to perform the passive alignment using the guide pin, in addition to increasing the dimensional accuracy of the optical fiber fixing engaging portion in the optical fiber fixing device, the guide pin for the optical fiber fixing engaging portion is required. The position accuracy of the (guide pin after being engaged with the optical fiber fixture) is determined by the value of the core diameter of the optical fiber to be optically connected by the optical fiber fixture by one.
It is desired to be within about / 10.

Therefore, when an optical fiber guide block made of glass capable of passive alignment is to be manufactured by machining, the optical fiber fixing engaging portion is formed with high dimensional accuracy. Passive alignment is possible with regard to the positional accuracy of the optical fiber fixing engaging portion, the positional accuracy of the alignment mark with respect to the optical fiber fixing engaging portion, or the positional accuracy of the guide pin with respect to the optical fiber fixing engaging portion. It is necessary to raise to the extent.

However, when an optical fiber guide block made of glass is to be manufactured by machining,
Although it is relatively easy to form the optical fiber fixing engagement portion with high dimensional accuracy, the positional accuracy of the optical fiber fixing engagement portion described above and the alignment mark of the optical fiber fixing engagement portion are described. It is difficult to increase the positional accuracy or the positional accuracy of the guide pin with respect to the optical fiber fixing engagement portion to the extent that passive alignment is possible. As a result, when an optical fiber guide block made of glass capable of passive alignment is to be manufactured by machining, there is a problem that the manufacturing cost is high and mass production is difficult.

For this reason, glass optical fiber guide blocks will be mass-produced at low cost by molding (also called hot molding or press molding) using a glass molding preform and a predetermined molding die. Attempts have been made.

[0012]

Although glass molding is suitable as a means for mass-producing a high-precision molded product, an optical fiber guide having an optical fiber fixing engaging portion and a pedestal portion. In order to obtain a glass molded product that is thin as a whole and has a change in thickness such as a step by molding, a flat glass-shaped preform, that is, glass molding whose vertical and horizontal cross-sections are both rectangular. The use of the preform causes the following problems.

That is, the glass is applied to a thick portion of the molded product (for example, in an optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion, the side where the optical fiber fixing engaging portion is formed). Filling seems to be insufficient,
As a result, the molding accuracy of the thick portion is reduced. For example, when an optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion is to be obtained, the size of the optical fiber fixing engaging portion is reduced. The accuracy and the external shape accuracy of the thick portion where the optical fiber fixing engagement portion is located are likely to be reduced. Filling of the glass into the thick part can be sufficiently performed by increasing the molding pressure, but in this case, the life of the molding die is shortened, and molding burrs are easily generated. Problems arise.

An object of the present invention is to mold a thin plate-shaped molded product requiring a large flow of glass during molding, such as a thin plate-shaped optical fiber fixing member having a large change in thickness such as a step, with high precision. An object of the present invention is to provide a glass preform that can be used and a method for manufacturing an optical fiber fixing member using the glass preform.

[0015]

SUMMARY OF THE INVENTION The present inventors have found that an optical fiber guide block having an engaging portion for fixing an optical fiber and a pedestal portion is generally thin and has a change in thickness such as a step. In the case of using a flat glass preform to obtain a glass molded product by molding, we sought to find out why it is difficult to obtain a molded product with high molding accuracy, especially with high molding accuracy for thick parts, and concluded the following conclusions Reached.

That is, when a flat glass preform is molded, a portion of the glass preform that will become a thin part of the molded product is first pressed, and a portion of the excess glass at this time is subjected to glass forming. It flows toward the place where the thick part of the molded article is formed in the preform. Since the viscosity of glass during molding is higher than the molding viscosity of plastics, etc., and the flow resistance is large, if the frictional resistance between the glass and the inner surface of the mold is large, the fluidity of the glass near the mold surface will be significantly impaired. You. In particular, when the molded product is thin, the distance between the upper mold surface and the lower mold surface is short, and the fluidity of the glass is easily hindered.

Therefore, the larger the contact area between the upper mold and the glass (preliminary glass forming body) and the contact area between the lower mold and the glass (preliminary glass forming body) in the initial stage of molding, the thinner part of the molded product becomes. The flow of the glass from the location where is to the location where the thick part of the molded article is to be formed is hindered. As a result, glass is filled in the thick portion of the molded product (for example, in the optical fiber guide block having the optical fiber fixing engaging portion and the pedestal portion, the side where the optical fiber fixing engaging portion is formed). It becomes short and the accuracy of the outer shape of the thick part is reduced. This tendency becomes more conspicuous as the overall thickness of the molded article becomes thinner, and as the height difference of the step portion occupying the maximum thickness in the molded article becomes larger.

The present invention has been made based on the above findings, and a glass forming preform according to the present invention for achieving the above object has a polygonal cross section in the radial direction and is surrounded by two or more conical curves. A glass column having a shape surrounded by one or more straight lines and one or more conical curves, and satisfying any of the following conditions (i) to (iii): (Hereinafter, this glass forming preform is referred to as “glass forming preform I”).

(I) The height is equal to that of the glass forming preform, the cross section in the radial direction has a rectangular frame shape, and each of the four inner side surfaces is only in contact with the side surface or the ridge of the glass forming preform. Assuming that the glass forming preform is inserted into a cylinder having an inner dimension, at least one of the four inner side surfaces of the cylinder comes into line contact with the side surface of the glass forming preform.

(Ii) Assuming that the glass forming preform has been inserted into the cylindrical body, one to three of the four inner side surfaces of the cylindrical body have the same shape as the side surfaces of the glass forming preform. Line contact with the ridge and the glass forming preform is 4
It has more than one side.

(Iii) Assuming that the glass preform is inserted into the cylinder, four inner side surfaces of the cylinder come into surface contact with the side faces of the glass preform, respectively.
And the glass preform has five or more side surfaces.

Further, another glass forming preform according to the present invention for achieving the above object is a glass pillar having a radial cross section surrounded by one conical curve. It is characterized in that it is used to obtain a thin plate-shaped molded product having a maximum thickness of 5 mm or less or (b) a molded product having a step portion whose height direction is substantially parallel to the pressing direction during molding. (Hereinafter, this glass forming preform is referred to as “glass forming preform II”).

On the other hand, the method for producing a glass forming preform according to the present invention is characterized in that the glass forming preform I or the glass forming preform II according to the present invention is placed such that the side surface of the glass forming preform is positioned in the pressing direction during molding. The glass molding preform is heated to a temperature at which the glass molding preform can be molded, and molded into an optical fiber fixing member. Things.

[0024]

Embodiments of the present invention will be described below in detail. First, the glass forming preform I of the present invention
As described above, this glass forming preform I has a polygonal cross section in the radial direction as described above, a shape surrounded by two or more conic curves, or one or more straight lines and one or more conical curves. And is a glass pillar having a shape surrounded by a circle, and satisfies any of the above conditions (i) to (iii). Here, the reason why the glass forming preform I of the present invention satisfies any of the above conditions (i) to (iii) is as follows.

That is, the fluidity of the glass at the time of molding is significantly impaired by the frictional resistance with the inner surface of the mold, and the desired molded product is an optical fiber guide block having an optical fiber fixing engagement portion and a pedestal portion. If the overall thickness is small and there is a change in thickness such as a step, as described above, the thick portion (for example, the optical fiber fixing engagement portion and the pedestal portion) In the optical fiber guide block having the optical fiber guide block, the glass is less likely to be filled into the optical fiber fixing engagement portion. In some cases, the insufficient filling can be solved by increasing the pressure during molding, but when molding is performed at a high pressure, molding burrs are easily generated and the mold is easily damaged.

Therefore, for example, when an optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion is to be molded with high molding accuracy at a practical pressing force, the upper mold and the glass ( It is desirable that the frictional resistance between the lower mold and the glass (the glass forming preform) be as small as possible. From the viewpoint of reducing the frictional resistance, the contact area between the upper mold and the glass forming preform at the time when the upper mold contacts the glass forming preform, and the glass forming preform was arranged on the lower mold. It is preferable to select the shape of the glass forming preform so that the contact area between the lower mold and the glass forming preform at this time becomes small.

At this time, since the volume of the glass preform is constant according to the volume of the target molded product regardless of its shape, the contact area between the upper mold and the glass preform or the lower mold and the glass As the shape of the glass preform is selected so that the contact area with the preform is reduced, it is necessary to increase the thickness of the glass preform. And, the thicker the glass forming preform is, the more the deformation of the glass forming preform at the time of molding is increased, and accordingly, the glass is set in the forming die (in the cavity).
It is difficult to spread them evenly.

However, once the glass and the inner surface of the mold are in contact with each other, the flow of the glass at the contact portion is hindered, and the flow of the glass toward the portion where the inner surface of the mold and the glass have not yet contacted has priority. To happen. Therefore, in order to obtain an optical fiber fixing member having high external shape accuracy even when a thick glass molding preform is used, the inner side surface of the molding die (the molding die is an upper die, a trunk die, and a lower die). (The inner side of the body mold if it consists of, or the inner side of the upper mold or the inner side of the lower mold if the mold consists of an upper mold and a lower mold) and the glass forming preform as much as possible. It is preferred that the contact be made early so that the flow of the glass toward the portion where the inner surface of the mold and the glass have not yet contacted occurs preferentially. To this end, an optical connection side end surface (which means a side surface located on a side connected to another optical fiber fixing member or an optical component at the time of optical connection among the side surfaces of the optical fiber fixing member) or. A side surface to be the optical connection side end surface (which means a side surface that is polished in a later step to become an optical connection side end surface. Hereinafter, the side surface and the optical connection side end surface are collectively referred to as an “optical connection side end surface”). When looking at the glass forming preform in the cavity (but not yet formed) from the inner side of the forming mold, the glass forming preform with the vertical side extending from the lower surface to the upper surface in the width direction It is more preferable to use a glass forming preform having a shape in which the side portion in the width direction protrudes outward than to use.

For the reasons described above, the glass forming preform I of the present invention satisfies any of the above conditions (i) to (iii). The glass preform is subjected to the conditions (i) to (iii) described above.
Is satisfied, the contact area between the upper mold and the glass forming preform (the contact area at the time when the upper mold is in contact with the glass forming preform) is higher than when the flat glass preform is used. ) Or the glass molding preform can be arranged in the molding die such that the contact area between the lower mold and the glass molding preform is reduced, and accordingly, the optical fiber fixing member as a molded product is reduced. It is possible to improve the molding accuracy, particularly the molding accuracy of the thick part.

The glass forming preform I satisfying the above condition (i) may be a columnar object (excluding a columnar object and an elliptical columnar object) having a curved side surface or at least one of a curved surface. It is a pillar having a side surface and at least one side surface composed of a flat surface. That is, the above condition (i)
The glass forming preform I satisfying the above condition has a radial cross-sectional shape of 2
A columnar object having a shape surrounded by one or more conic curves or a shape surrounded by one or more straight lines and one or more conic curves. Examples of the glass forming preform I include those having a radial cross section shown in FIGS. 4A to 5G and FIGS. 5A to 5I, but are not limited thereto. Not something. In FIGS. 4 and 5, reference numeral 21 denotes a glass forming preform I, and reference numeral 22 denotes an inner side surface of the cylindrical body in the condition (i).

The glass forming preform I satisfying the above condition (ii) has a total number of side surfaces of 4 or more, at least two of which are flat surfaces, and at least two of the side surfaces formed of these flat surfaces are adjacent to each other. Pillars. That is, the glass forming preform I satisfying the above condition (ii) is:
It is a column-shaped object whose radial cross-sectional shape is a polygon or a shape surrounded by two or more straight lines and one or more conical curves. However, the condition (ii) stipulates that the number of ridges that are in line contact with the inner side surface of the cylindrical body is one to three, and therefore does not include a square pole. Examples of the glass forming preform I include those having a radial cross section shown in FIGS. 6A to 6C, but are not limited to these. In FIG. 6, reference numeral 31 denotes a glass forming preform,
Reference numeral 32 denotes an inner side surface of the cylindrical body referred to in the above condition (ii). 4 (f) and 4 (g) and FIG.
Each of the glass forming preforms 21 shown in (b), (e), (g) and (h) simultaneously satisfies the conditions (i) and (ii).

The glass forming preform I satisfying the above condition (iii) is a columnar member having a total number of side faces of 5 or more, at least four of which are flat. That is,
The glass forming preform I that satisfies the above condition (iii) is a columnar object having a radial cross-section having a polygonal shape or a shape surrounded by four or more straight lines and one or more conical curves. Examples of the glass forming preform include those having a radial cross section shown in FIGS. 7A to 7D.
It is not limited to these. In FIG. 7, reference numeral 41 denotes a glass forming preform I, and reference numeral 42 denotes an inner side surface of the cylindrical body in the above condition (iii).

The cross-sectional shapes shown in FIGS. 4 to 7 (the cross-sectional shapes in the radial direction of the glass preform I) are all left-right (left-right in FIGS. 4 to 7) symmetrical shapes. The cross-sectional shape of the glass forming preform I does not have to be symmetrical, not to mention the case where the target molded product is not symmetrical in shape, but also in the case of symmetrical shape. In addition, all of the cross-sectional shapes shown in FIGS. 4 to 7 have the glass forming preform I on each of four inner side surfaces of a cylindrical body having a rectangular cross-sectional shape (excluding a rectangular frame shape) in a radial direction. A shape in which the side surfaces or the ridges of the side surfaces are in contact with each other, but the side surfaces or the ridges of the side surfaces of the glass forming preliminary body are in contact with the four inner side surfaces of the cylindrical body having a rectangular cross-sectional shape in the radial direction. May be used.

The above-mentioned glass forming preform I of the present invention comprises:
As will be described later, it is suitable as a glass forming preform for obtaining an optical fiber fixing member by molding, but a glass pillar having a radial cross-sectional shape surrounded by one conic curve, that is, Since the glass forming preform II of the present invention, which is a glass pillar having a circular or elliptical cross section in the radial direction, also satisfies the above condition (i), the optical fiber fixing member is molded by molding. It is suitable as a glass forming preform to be obtained by the above method. However, the glass forming preform itself having a circular or elliptical cross-sectional shape in the radial direction is disclosed in JP-A-61-127.
According to Japanese Patent Publication No. 626 and Japanese Patent Publication No. 7-42124,
Alternatively, it is known as a glass forming preform for an optical fiber.

However, the above-mentioned Japanese Patent Application Laid-Open No.
A glass forming preform (a glass material for forming) described in Japanese Patent No. 626 is for obtaining an optical element column as an intermediate product when obtaining an optical element such as a prism by press molding. The glass forming preform described in Japanese Patent Publication No. 7-42124 is a cylindrical rod cut out from a cylindrical high-purity quartz glass ingot produced by a gas phase reaction method or a Bernoulli method. . The invention described in Japanese Patent Publication No. 7-42124 discloses that the high-purity quartz glass ingot is pressed from a predetermined direction to obtain a quartz glass plate expected as a substrate material for a display or the like. And in the example described in the publication, a thickness of 21 m
m quartz glass plate is obtained. On the other hand, a glass forming preform for an optical fiber is used for obtaining an optical fiber.

Accordingly, the above-mentioned Japanese Patent Application Laid-Open No. 61-1276 shows
No. 26 and Japanese Patent Publication No. 7-42124, both of the glass forming preform and the glass forming preform for optical fiber have the same (a) maximum thickness as the glass forming preform II of the present invention. Recognized as being used to obtain a thin plate-shaped molded product of 5 mm or less or (b) a molded product having a step portion whose height direction is substantially parallel to the pressing direction during molding. I can't.

The cross-sectional shape and size of the glass forming preforms I and II of the present invention in the radial direction, except for the location where a rolling prevention portion described later is provided, are set at the bottom surface of the glass forming preforms I and II. Is preferably substantially the same from the bottom surface to the top surface, but the size may be gradually or stepwise reduced or increased from the bottom surface to the top surface. The sectional shape in the radial direction does not necessarily have to be similar from the bottom surface to the top surface.
Is within the range of the shape satisfying the above conditions (i) to (iii), and for the glass forming preform II, "the cross-sectional shape in the radial direction exhibits a shape surrounded by one conic curve." May be continuously changed as long as the condition is satisfied.

When the size of the cross-sectional shape is changed from the bottom surface to the upper surface, the size of the cross-sectional shape on the side of the bottom surface and the upper surface on which the optical connection side end face of the optical fiber fixing member is formed is formed. It is preferable that the height is larger than the size of the cross-sectional shape on the other surface side. Both the bottom surface and the top surface are preferably flat from the viewpoint of improving the filling property of the glass into the corners of the cavity of the molding die, but within a range where the optical fiber fixing member having the desired molding accuracy can be obtained. A part or the whole thereof may be a curved surface that is convex outward or a curved surface that is convex inward.

The glass forming preform I of the present invention has a polygonal cross section in the radial direction, a shape surrounded by two or more conical curves, or one or more straight lines and one or more conical curves. And the above conditions (i) to (i)
ii), as described above, the contact area between the upper mold and the glass forming preform (when the upper mold is The glass forming preform I is formed such that the contact area at the point of contact with the lower mold and the contact area between the lower mold and the glass forming preform (the contact area when the glass forming preform is arranged on the lower mold) are reduced. Can be placed in the mold,
Thereby, it is possible to improve the molding accuracy of the optical fiber fixing member, which is a molded product, particularly the molding accuracy of the thick portion.

On the other hand, the glass forming preform II of the present invention satisfies the condition (i) as described above,
Similar to the glass preform I of the present invention, the contact area between the upper mold and the glass preform (the contact area at the time when the upper Area) or the contact area between the lower mold and the glass forming preform (the contact area when the glass forming preform is placed on the lower mold) is to be arranged in the forming mold. Accordingly, it is possible to improve the molding accuracy of the optical fiber fixing member, which is a molded product, particularly the molding accuracy of a thick portion.

The glass forming preform I satisfying any one of the above conditions (i) to (iii) includes one having a cross-sectional shape (radial cross-sectional shape) that easily rolls when placed in a forming die. The cross-sectional shape (radial cross-sectional shape) that is easy to roll when placed in the mold even in the glass preform II
However, it is preferable that such glass forming preforms I and II are provided with a rolling prevention part as necessary. As a specific example of this rolling prevention unit,
A flat portion formed partially or as one side surface on the side surfaces of the glass forming preforms I and II, and a plurality of glass formed on the side surfaces of the glass forming preforms I and II using glass having the same composition or a different composition as the glass forming preforms Individual protrusions.

The glass forming preforms I and II of the present invention are particularly suitable for a molded article having a large change in thickness such as a step (the thickness of the molded article having a maximum change of about 10 to 30% of the maximum thickness).
%), The maximum thickness of the glass forming preforms I and II is 3 times the maximum thickness of the target molded product (optical fiber fixing member).
If it exceeds twice, the deformation of the glass forming preforms I and II during molding becomes too large, and it becomes difficult to obtain a molded product (optical fiber fixing member) having high external shape accuracy. When it is intended to obtain a molded product having a large change in thickness such as the step, the glass forming preforms I and II are set so that the maximum thickness is 1.4 times or more and 3 times or less the maximum thickness of the molded product. Is preferably formed in 1.6 to 2.
More preferably, it is formed so as to be eight times.

In order to obtain a molded product having a small change in thickness such as a step, the maximum thickness of the glass forming preforms I and II can be appropriately selected within a wider range. When the maximum thickness of I and II exceeds three times the maximum thickness of the target molded product (optical fiber fixing member), a molded product (optical fiber fixing member) with high external shape accuracy as described above can be obtained. Becomes difficult. On the other hand, when the maximum thickness of the glass forming preforms I and II is less than 1.1 times the maximum thickness of the target molded product (optical fiber fixing member), the deformation amount of the glass forming preforms I and II during molding is reduced. Is too small, and the transferability decreases. Therefore, when it is intended to obtain a molded product having a small change in thickness such as the step, it is preferable that the maximum thickness of the glass forming preforms I and II is 1.1 to 3 times the maximum thickness of the molded product. , 1.2-
More preferably, it is 2.5 times.

Here, the "maximum thickness of the glass forming preform" referred to in the present specification is the largest thickness in the direction parallel to the pressing direction when the glass forming preform is used (at the time of molding). Means the thickness of the part. Further, the “maximum thickness of a molded product” in the present specification means the thickness of the thickest part in the thickness of the molded product in a direction parallel to the pressing direction during molding.

When a holding plate having a simple flat plate shape is formed, the glass forming preforms I and II only need to have a thickness sufficient to compensate for a change in the outer diameter by the forming. , II can be less than 1.1 times the maximum thickness of the molded article.

The glass preforms I and II of the present invention having the above-described cross-sectional shape and thickness may be made of glass that can be molded. In order to prevent the release film and the mold from being damaged during molding,
It is preferably made of glass having a temperature of 0 ° C. or less, and particularly preferably having a deformation point of 540 ° C. or less.

The optical fiber fixing member used for optically connecting an optical waveguide formed on a substrate such as quartz glass or silicon having a small coefficient of thermal expansion to a silica-based single mode optical fiber is subject to temperature change. In order to reduce the connection loss at the optical connection portion due to the above, it is desirable to form the optical connection portion from glass having a small average thermal expansion coefficient. Therefore, as glass forming preforms I and II for obtaining an optical fiber fixing member for such an application, -50 to +
It is preferably made of glass having an average coefficient of thermal expansion at 100 ° C. of 70 × 10 ⁻⁷ / ° C. or less.

On the other hand, when assembling into an optical fiber array, fixing of the optical fiber fixing members (optical fiber guide block and holding block) and fixing of the optical fiber array to another optical fiber array or optical component can be performed with high workability. As described above, it is desirable to use an ultraviolet-curable adhesive for fixing, as described above. Therefore, as glass forming preforms I and II for obtaining an optical fiber fixing member that can be fixed to another member using an ultraviolet curable adhesive, ultraviolet rays having a wavelength of 350 nm have a thickness of 2 mm and a thickness of 30% or more. Preferably made of glass that transmits 60% or more, or a wavelength of 300 nm
Made of glass that transmits 60% or more of the ultraviolet rays with a thickness of 2 mm.

When the yield point is 600 ° C. or less, -50 to +10
Glass having an average thermal expansion coefficient at 0 ° C. of 70 × 10 ⁻⁷ / ° C. or less and transmitting 30% or more of ultraviolet light having a wavelength of 350 nm at a thickness of 2 mm and a thickness of 2 mm is, for example, SiO ₂ , B ₂ O ₃ and Z.
It can be obtained by using nO as a glass component.

As specific examples of the above-mentioned glass, ₁ to 30% by weight of SiO ₂ and 15 to 4% of B ₂ O ₃ are used as glass components.
0 wt%, ZnO 40-60 wt% (but not 40 wt%), MgO 0-15 wt%, CaO 0-10 wt%
%, 0-10 wt% of SrO, 0-10 wt% of BaO, P
0 to 20 wt% of bO, ZnO, MgO, CaO,
The total amount of SrO, BaO and PbO is 40-60 wt%
(Where 40 wt% are not included.), And further, Al ₂
Glass containing 0 to 10 wt% (but not 0 wt%) of O ₃ and having a total content of the above glass components of 75 wt% or more (hereinafter, this glass is referred to as “first glass”). .

The first glass is made of SiO ₂ of 3 to 30%.
wt%, B ₂ O ₃ and 20 to 40 wt%, the ZnO 40～55W
t% (excluding 40 wt%), 0-15 wt% MgO
%, 0-10 wt% CaO, 0-10 wt% SrO, B
containing 0 to 10 wt% of aO and 0 to 20 wt% of PbO;
The total amount of nO, MgO, CaO, SrO, BaO and PbO is 40 to 55 wt% (but not including 40 wt%), and further, 0.5 to 10 wt% of Al ₂ O ₃ and 0 to 0 of Li ₂ O. It is particularly preferred that the content be 7 wt% (hereinafter, this glass is referred to as “second glass”).

The first glass and the second glass are:
Further, 0-10 wt% of GeO ₂ (however, SiO ₂ and Ge
The total amount with O ₂ is ₃ to 30 wt%), and La ₂ O ₃ is 0 to 20 w
t%, 0-10 wt% of Y ₂ O _3, 0~10wt the Gd ₂ O ₃
% (However, the total amount of La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ is 0%
~20wt%), Nb ₂ O ₅ and 0-10 wt%, the total amount of Ta ₂ O ₅ and 0-10 wt% (provided that Nb ₂ O ₅ and Ta ₂ O ₅ 0
10 wt%), a ZrO ₂ 0-5 wt%, the TiO ₂ 0 to
It may contain 3 wt%. Further, for the purpose of improving defoaming and coloring, As ₂ O ₃ , Sb ₂ O ₃ ,
One or more of SnO and SnO ₂ may be added. However, As ₂ O ₃ , Sb ₂ O ₃ , SnO, S
Even if nO ₂ is added in a total amount exceeding 4 wt%, the effect of improving defoaming and coloring is not improved. Therefore, it is desirable to use these components in a total amount of 0 to 4 wt%. further,
In addition to the above-mentioned components, F, Bi ₂ O ₃ , Yb ₂ O ₃ , WO _{3 and the} like are appropriately added to the extent that the properties of the glass are not deteriorated, and trace amounts of Na ₂ O and K ₂ O are added. There may be.

The glass forming preforms I and II of the present invention are obtained by cold working, extrusion forming,
It can be manufactured by forming into a predetermined shape by a method such as stretching. When the target glass forming preform is the glass preforming body I, a rod having a predetermined cross-sectional shape in the radial direction is hot-formed by a method such as extrusion molding or elongation molding, and is formed into a predetermined length. By cutting, or by grinding after cutting, it is possible to manufacture at low cost. Further, when the target glass forming preform is the glass forming preform II, it can be manufactured at low cost by cold working using a diamond grindstone.

The glass molding preforms I and II of the present invention, which can be manufactured as described above, comprise an optical fiber guide block having only an optical fiber fixing engaging portion, an optical fiber fixing engaging portion and a pedestal portion. It can be used as a glass forming preform for obtaining various glass optical fiber fixing members such as an optical fiber guide block, a holding block for an optical fiber, a holding block for a covering portion, and a holding block for both purposes. In particular, it is suitable as a glass forming preform for obtaining a glass optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion by molding. The molding of the optical fiber fixing member using the glass preforms I and II of the present invention can be performed, for example, based on the method of manufacturing the optical fiber fixing member of the present invention described in detail below.

As described above, the method of the present invention comprises the preform I or the preform II of the present invention.
(Hereinafter, unless otherwise specified, the “glass preform” refers to the glass preform I or the glass preform II of the present invention.
Shall mean. ) Is placed in a mold having a cavity having a predetermined shape such that the side surface of the glass forming preform is positioned in the pressing direction at the time of molding, and a temperature at which the glass forming preform can be molded. , And molded into an optical fiber fixing member.

When disposing the glass forming preform in the forming die, as described above, the side surface of the glass forming preform is positioned in the pressing direction at the time of molding, that is, the glass forming preform is placed. While lying down, place it in the mold. At this time, as described in the description of the glass forming preform of the present invention, the contact area between the upper mold and the glass forming preform (the upper mold is The contact area between the lower mold and the glass forming preform (the contact area when the glass forming preform is placed on the lower mold) and the glass The preform is arranged such that the bottom or top surface forms the end face on the optical connection side of the optical fiber fixing member.

The mold used in the method of the present invention is
What is necessary is just to have the cavity of a predetermined shape according to the shape of the target optical fiber fixing member. Since this mold is for obtaining an optical fiber fixing member,
The basic shape of the cavity in plan view is a rectangle,
In addition, the four inner side surfaces are basically planes. However, among the side surfaces of the optical fiber fixing member, the side surface on the side facing the optical connection end surface (hereinafter, this side surface is referred to as a “rear side surface”) has a curved surface that is convex inward or a curved surface that is convex outward. Therefore, the molding surface (one of the inner side surfaces of the mold) for forming the rear side surface may be a curved surface that is convex inward or a curved surface that is convex outward. Details of the mold will be described later.

Since the glass forming preform used in the method of the present invention is a columnar material, the glass forming preform is placed in a forming die such that the side surface thereof is positioned in the pressing direction during the molding as described above. When they are arranged, the shape in plan view of the glass forming preform is similar to the shape in plan view of the target molded product (optical fiber fixing member). By using a glass forming preform whose shape in plan view approximates the shape of the target molded product in plan view, it is possible to spread the glass substantially evenly in the mold during molding. As a result, it is possible to effectively prevent the occurrence of local molding burrs and insufficient transfer accuracy.

When the sectional shape in the radial direction of the glass forming preform is bilaterally symmetric, and when the thickness is not bilaterally symmetric but the thickness is substantially the same in the left and right, the glass is molded in the molding die at the time of molding. In order to substantially uniformly spread the glass preform, it is preferable to dispose the glass preform in the mold so that the distance between the side surface of the glass preform and the inner side surface of the mold is equal. Here, "the distance between the side surface of the glass forming preform and the inner side surface of the forming die" in the present invention means that the forming die and the glass forming preform arranged in the forming die are viewed in plan. One of the two side surfaces (the inner side surface of the molding die) that forms the side surface (the side surface as viewed from the optical connection side end surface) of the optical fiber fixing member among the inner side surfaces of the molding die and the glass This means that the gap between the glass preform and the gap between the other side (the inner side face of the mold) and the glass preform are substantially line-symmetric with each other.

Further, as described above, the glass forming preform used in the method of the present invention may have a cross-sectional shape in the radial direction that is gradually or gradually reduced or increased from the bottom surface to the top surface. However, when arranging such a glass forming preform in a mold, it is preferable to perform the following. That is, of the bottom surface and the top surface of the glass forming preform, the side having the larger cross-sectional shape in the radial direction forms the optical connection side end surface of the optical fiber fixing member, and the cross-sectional shape in the radial direction. It is preferable to dispose the glass forming preform in the forming die by biasing the larger surface side closer to the inner side surface of the forming die than the side having the smaller radial cross-sectional shape. At this time, the gap between each of the two side surfaces that form the side surface of the optical fiber fixing member (the side surface viewed from the optical connection side end surface) of the inner side surface of the forming die and the glass forming preform is: Depending on, for example, whether the thickness of the glass forming preform differs between left and right when viewed in its radial cross-sectional shape, the thickness is biased to one side or equalized.

In the method of the present invention, the glass forming preform is placed in a forming die and molded as described above.
Molding conditions at this time, depending on the dimensional accuracy and shape accuracy required for the target optical fiber fixing member, the composition of the glass molding preform, the heating medium and atmosphere used for molding, etc. Is approximately 100-3
Within the scope of 00kgf / cm ^2, within the range of temperature at which the viscosity of the glass is approximately 10 ⁷ to 10 ^9.5 poise is the temperature conditions are appropriately selected.

According to the above-described method of the present invention, for example, as a whole, an optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion is thin, and there is a change in thickness such as a step. Even in the case of obtaining the optical fiber fixing member, it is possible to suppress the occurrence of insufficient glass filling in the thick portion (on the side where the optical fiber fixing engaging portion is formed) of the optical fiber fixing member. It is possible to obtain an optical fiber fixing member having high molding accuracy, particularly high molding accuracy for a thick portion. The method of the present invention is suitable as a method for obtaining a glass optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion by molding, and has only an optical fiber fixing engaging portion. It can be used as a method for obtaining various types of glass optical fiber fixing members such as an optical fiber guide block, an optical fiber holding block, a covering portion holding block, and a dual-use holding block.

The mold used in the method of the present invention is preferably one whose dimensional tolerance and shape tolerance are higher than the dimensional accuracy and shape accuracy of the target molded product. The molding die may be composed of an upper die and a lower die as long as it has a cavity of a predetermined shape according to the shape of a target molded product, or may be an upper die, a lower die and Although it may be composed of three types, it is necessary to obtain an optical fiber fixing member having as high dimensional accuracy and shape accuracy as possible. The following three are preferred. Further, it is preferable to have a stopper for stopping the movement of the movable mold (the mold that moves in the pressing direction at the time of molding) at a predetermined position so that a molded article having a desired thickness is obtained.

The molding die is a mold element (when the molding die comprises an upper die and a lower die, it refers to each of the upper die and the lower die. Refers to each of the upper mold, the lower mold, and the body mold.) The mold elements are combined so that a predetermined clearance (gap) is formed between the molds. The “mold having a cavity of a predetermined shape” means a mold capable of forming a closed space corresponding to the shape of a target molded article except for a clearance between mold elements.

The mold material of each mold element preferably has oxidation resistance and non-reactivity with glass that can be used for glass molding, and does not cause structural change or plastic deformation under a high temperature environment. Examples thereof include silicon carbide,
Silicon nitride, tungsten carbide, alumina, zirconia,
Crystallized glass, silicon, cermets of titanium carbide and titanium nitride, and the like can be given. Each mold element can be obtained by forming a desired mold material into a predetermined shape, and then coating the surface with a release film of carbon or platinum alloy for release.

When an optical fiber guide block having only an optical fiber fixing engagement portion is manufactured by the method of the present invention, a mold having two mold elements, an upper mold and a lower mold, may be used. Alternatively, an upper mold, a lower mold and a body mold may be used. In any case, a mold element having a molding surface for forming a side surface of a target optical fiber guide block (for a mold having two mold elements, an upper mold and a lower mold, an upper mold and a lower mold are used. Either one (usually the lower mold), the upper mold, the lower mold, and the mold in the case of the mold composed of three mold elements of the body mold)
The average coefficient of thermal expansion at room temperature to 400 ° C. is 5 × 10 ⁻⁷ / ° C. to 70 ° C. higher than the average coefficient of thermal expansion of the glass forming preform.
It is preferable to be made of a mold material smaller by × 10 ^-7 / ° C.

Using a mold material having an average coefficient of thermal expansion between room temperature and 400 ° C. that is larger than the average coefficient of thermal expansion of the glass molding preform, a mold element having a molding surface for forming the side surface of the optical fiber guide block is produced. In the case where the mold element is produced using a mold material having a difference of less than 5 × 10 ⁻⁷ / ° C. even though it is smaller than the average thermal expansion coefficient of the glass forming preform, From the mold element. On the other hand, even if the average thermal expansion coefficient of the mold material from room temperature to 400 ° C. is smaller than the average thermal expansion coefficient of the glass forming preform, the difference is 7%.
If it is larger than 0 × 10 ⁻⁷ / ° C., the molded article after molding is pulled by the wall surface of the mold element in the process of cooling through a high temperature range in which the glass can be deformed. The dimensional accuracy and the shape accuracy of the resulting optical fiber guide block deteriorate. As the mold material of the mold element, the average thermal expansion coefficient at room temperature to 400 ° C. is 7 × 10 ⁻⁷ / ° C. to 40 × higher than the average thermal expansion coefficient of the glass forming preform.
Those smaller by 10 ⁻⁷ / ° C. are particularly preferred.

A mold used for manufacturing an optical fiber guide block having an optical fiber fixing engaging portion and a pedestal portion by the method of the present invention is a mold for forming the optical fiber fixing engaging portion. An optical fiber guide block having only an optical fiber fixing engaging part, except that a mold element having a first molding part and a second molding part for forming a pedestal part is used as an upper mold or a lower mold. Can be conformed to the above-mentioned mold used when manufacturing the above.

The mold element having the first molded portion and the second molded portion can be obtained by processing one member by machining, etching, or the like. It is necessary to provide a step between the second molded portion and the first molded portion having a desired accuracy on one member by machining, etching, or the like even in the step portion and the vicinity thereof. Have difficulty. Therefore, it is preferable that the mold element is obtained by forming the first molded portion and the second molded portion into separate members by machining, etching, or the like, and then integrating these members.

The mold element formed by integrating the member on which the first molded portion is formed and the member on which the second molded portion is formed is formed by using an adhesive such as a heat-resistant adhesive. It can be obtained by integrating the members, mechanically integrating the two members using a fixing member such as a fixing frame, or integrating the two members using an adhesive and a fixing member together. it can. In order to obtain a mold element having a desired accuracy and easily making the clearance between the mold elements arranged close to each other, for example, 10 μm or less, two or more members are mechanically integrated. Is preferred.

On the other hand, the forming die used when manufacturing the holding block by the method of the present invention is similar to the above-mentioned forming die used when manufacturing the optical fiber guide block having only the optical fiber fixing engaging portion. be able to.

Regardless of whether the optical fiber guide block or the holding block is obtained, the mold element for forming the concave portion or the mold material of the molded portion has a releasability that varies according to the shape and size of the concave portion. In consideration of the above, the average thermal expansion coefficient at room temperature to 400 ° C. is 5 × 10 ⁻⁷ / ° C. to 70 × 1 more than the average thermal expansion coefficient of the glass forming preform.
It is preferable to use a mold material that is larger by 0 ⁻⁷ / ° C. as appropriate.

[0073]

Embodiments of the present invention will be described below. Example 1 (1) Production of optical fiber guide block First, 13.3 wt% of SiO ₂ and 32.2 wt% of B ₂ O ₃ were used.
%, ZnO 44.5 wt%, Al ₂ O ₃ 5.5 wt%,
A glass material containing 4.5% by weight of Li ₂ O and 0.1% by weight of SnO ₂ at an externally added amount is extruded hot and has a cross-sectional shape in a direction perpendicular to the longitudinal direction. A rod having an abacus ball shape was prepared, and the rod was cut into a predetermined length in a cold state to obtain a columnar glass forming preform having a height of 10.5 mm.

The sectional shape and the size in the radial direction of the glass forming preform are substantially the same from the bottom surface to the top surface, and the sectional shape is similar to the shape shown in FIG. It has an abacus ball shape. That is, the cross-sectional shape in the radial direction of the glass forming preform includes a pair of horizontal sides facing each other, an outwardly convex curved side connecting the left ends of these sides, and the pair of horizontal sides. It has a shape surrounded by an outwardly convex curved side connecting the right ends of the sides. The length in the longitudinal direction (the left-right direction on FIG. 4 (a); the same applies hereinafter) in the cross section is 3.50 mm, and the widthwise direction (FIG.
(A) The direction orthogonal to the left-right direction above. same as below. ) Is 3.25 mm, and the length of each of the pair of horizontal sides (sides extending in the horizontal direction on FIG. 4A) is 1.0 mm. Further, the bottom surface and the top surface of the glass forming preform are each substantially flat. This glass forming preform is one of the glass forming preforms I of the present invention, and the glass forming preform satisfies the condition (i) described in the present invention.

The above glass material has a glass transition point of 477 ° C., a sag point of 511 ° C., an average thermal expansion coefficient from room temperature to 400 ° C. of 66.5 × 10 ⁻⁷ / ° C. and a wavelength of 350 nm at a thickness of 2 mm. Ultraviolet ray transmittance is 90% or more.

As a mold material, tungsten carbide (average coefficient of thermal expansion from room temperature to 400 ° C .; 55 × 10 ⁻⁷ /
C) to obtain a molding die composed of an upper die, a lower die and a body die. As shown in FIG. 1, an upper mold 2 constituting the above-mentioned molding die 1 has a first molding portion 3 for forming eight optical fiber fixing engagement portions formed of V grooves and parallel to each other. And a second forming portion 4 for forming a pedestal portion having the same width as the width of the optical fiber guide block on the optical fiber guide block.

The first molded portion 3 has a quadrangular prism shape, and has a rectangular vertical cross section at the lower end in use corresponding to the shape of the optical fiber fixing engaging portion to be formed. 5 mm in length, 170 μm in height, and 25 in width of the base in which the vertical cross section in the short direction is an isosceles triangle.
Eight convex portions 3a of 0 μm are formed parallel to each other at a pitch of 250 ± 0.3 μm. Also, the first molded part 3
At the upper end portion during use, a collar portion 3b that is locked by the upper surface of the body mold 5 during use is formed except for a surface side that is in contact with the second molded portion 4.

On the other hand, the second molded portion 4 also has a quadrangular prism shape, but the lower surface when used is a flat surface, and the lower surface is the lower surface when the first molded portion 3 is used (eight convex portions 3).
(a plane excluding a) and protrudes downward by 250 μm (downward during use). Therefore, there is a step at the boundary between the first forming part 3 and the second forming part 4. Also, at the upper end portion of the second molded portion 4 during use, a brim portion 4a locked by the upper surface during use of the body mold 5 is formed except for the surface side in contact with the first molded portion 3. ing.

The first forming part 3 and the second forming part 4 are respectively composed of separate members, and each member is mechanically integrated by a fixed frame 6. The fixing frame 6 is fixed to each member by screws (not shown) made of tungsten carbide (average coefficient of thermal expansion from room temperature to 400 ° C .; 55 × 10 ⁻⁷ / ° C.). The clearance between the first molded part 3 and the second molded part 4 is 4 μm.

The barrel mold 5 is for forming the side face of the target optical fiber guide block by its inner side face, and is formed of a cylindrical body having a rectangular frame shape with a horizontal cross section. A fixed frame engaging portion 5a that engages with the fixed frame 6 is formed. The inner dimension of the body mold 5 in plan view is 5 × 12 mm. At the time of molding, the upper mold 2 described above reaches a predetermined depth from above when the body mold 5 is used, that is, until the flanges 3b and 4a of the upper mold 2 are locked by the upper surface of the body mold 5. Inserted. Therefore, the flange portions 3b and 4a of the upper die 2 function as stoppers during molding.

The lower mold 7 has a square pillar-shaped forming portion 7a for forming the bottom surface of the target optical fiber guide block, and the upper surface of the forming portion 7a when used is a flat surface. In addition, at the lower end when the molded part 7a is used,
Collar portion 7 for locking the lower surface when using trunk type 5
b is formed. At the time of molding, the lower die 7 is fixedly disposed, and the lower die 7 is disposed on the lower die 7 so that the lower surface of the lower die 7 is locked by the flange portion 7b. As a result, the upper surface of the molding part 7a is located in the internal space of the barrel die 5. The glass forming preform 8 is placed on the upper surface of the forming part 7a.

The above-mentioned lower surface of the first molding portion 3 and the side surface from the lower surface to the lower surface of the collar portion 3b,
, The side surface from the lower surface to the lower surface of the flange portion 4a, the inner side surface of the body die 5 (the fixing frame engaging portion 5).
a. ), And a 500-Å-thick platinum alloy release film 9 is formed on the upper surface of the molded portion 7a and on the side surface from the upper surface to the flange portion 7b by a sputtering method. The dimensional accuracy (dimensional accuracy with respect to pitch and height) of the eight projections 3 a having the release film 9 on the surface is within ± 0.3 μm. Three convex parts 3a
, The lower surface of the second molded part 4, the inner side surface of the body mold 5, and the flatness of the upper surface of the molded part 7a are all 1.0 μm.
m.

The upper mold 2 and the body mold 5 having the release film 9 described above.
The mold 1 including the upper mold 2 and the lower mold 7 has a clearance of 6 μm between the upper mold 2 and the body mold 5 and the clearance between the body mold 5 and the lower mold 7, respectively.
Of the lower surface of the first molded portion 3 (eight convex portions 3a
1.25) and the upper surface of the molded part 7a is 1.25.
mm, and the distance between the lower surface of the second molded part 4 and the upper surface of the molded part 7a is 1.00 mm. Using the molding die 1 and the glass preform 8 described above, molding was performed in the following manner to obtain an intended optical fiber guide block.

First, the trunk mold 5 is formed by the flange 7b of the lower mold 7.
After the two are engaged so that the lower surface of the lower die 7 is locked, a gap is formed substantially evenly on the upper surface of the molding portion 7a of the lower die 7 with the inner side surface of the trunk die 5. And the glass forming preform 8 was arranged. At this time, the glass forming preform 8
Was made so that the short side direction in the radial cross-sectional shape coincided with the vertical direction. Therefore, the maximum thickness of the glass forming preform 8 in a state where the glass forming preform 8 is arranged in the forming die 1 is 3.2.
5 mm, which is 2.6 times the maximum thickness (1.25 mm) of the target optical fiber guide block. Thereafter, the upper mold 2 was held above the body mold 5. FIG.
(A) shows the mold 1 and the glass preform 8 at this time.
FIG. 1 is a view schematically showing a vertical cross section in the lateral direction of FIG.
(B) shows the molding die 1 and the glass preform 8 at this time.
It is a figure which shows the outline of the vertical cross section of the longitudinal direction of FIG.

Next, the glass forming preform 8 placed on the upper surface of the lower mold 7 as described above was heated to 560 ° C.
(The viscosity of the glass at this time is 10 ⁹ poises.) The entire mold 1 is heated in a nitrogen atmosphere so that the viscosity becomes 10 ⁹ poises.
The upper die 2 was inserted into the die 5 at a molding pressure of 160 kgf / cm ² until the flanges 3b, 4a of the upper die 2 were locked on the upper surface of the die 5, and pressed for 140 seconds. FIG. 1C is a view schematically showing a vertical cross section of the molding die 1 and the molded product 10 in the lateral direction at this time, and FIG. 1D is a diagram showing the longitudinal direction of the molding die 1 and the molded product 10 at this time. FIG. 3 is a view schematically showing a vertical cross section of FIG.

Thereafter, the molded article 1 is cooled to room temperature, and
0 was taken out of the mold 1. The molded article 10 obtained is
As shown in FIG. 2, eight parallel optical fiber fixing engaging portions 11 each having a V-groove having a length of 5 mm, a depth of 170 μm, and a width of 250 μm at an upper end, and the optical fiber fixing engaging portions 11. An optical fiber guide block (hereinafter, referred to as “optical fiber guide block 10”) having, on one side, a pedestal portion 12 formed at a position one step lower than the upper end surface.
In the optical fiber guide block 10, the optical fiber guide block 10 has an optical fiber fixing engagement portion 11 of the side surfaces that form the contour of the optical fiber guide block 10 when viewed in plan.
Is polished back as it is or at a predetermined angle to form an optical connection side end surface.

The optical fiber guide block 10 has a width (width when the side surface 13 is set to the front) of 5 mm and a length of 1 mm.
2 mm, the maximum thickness is 1.25 mm, the width of the pedestal portion 12 is 5 mm, which is the same as the width of the optical fiber guide block, and the thickness is 1.00 mm. Therefore, the ratio of the height difference of the step (the step between the upper end surface of the optical fiber fixing engaging portion 11 and the surface of the pedestal portion 12) occupying the maximum thickness of the optical fiber guide block is as large as 20%.

Among the ridges of the optical fiber guide block 10, a clearance between the upper die 2 and the trunk die 5, a clearance between the lower die 7 and the trunk die 5, and a first molded portion of the upper die 2. The ridges at the locations corresponding to the clearances between the third and second molded portions 4 are each formed of a free surface, and the optical fiber guide block 10 has a substantially rectangular shape in plan view.

(2) Measurement and Evaluation of Accuracy The dimensional accuracy of the engaging portion 11 for fixing the optical fiber formed on the optical fiber guide block 10 was measured as follows. First, the tip is 25
Using a stylus-type contour shape measuring machine equipped with a stylus of μm (Contour Record 2600C manufactured by Tokyo Seimitsu Co., Ltd.), the stylus of the contour shape measuring machine is perpendicular to the longitudinal direction of the engaging portion 11 for fixing the optical fiber. The optical fiber fixing engaging portion 11 and the outline coordinates in the vicinity thereof were obtained by scanning in the direction in which the optical fiber was fixed, and the outline shape was displayed on the screen of the display device. Next, as shown in FIG. 3, each of the optical fiber fixing engagement portions 11 is displayed on the screen.
Each of the circles 15 having a diameter of 125 μm corresponding to the outer diameter of the silica-based single mode optical fiber is virtually inserted into each of them, and the circles 15 are formed on the two slopes (inner wall surfaces) of the optical fiber fixing engaging portion 11. The center coordinates of each circle 15 at the time of contact were determined.

Then, based on the center coordinates of each of the circles 15,
The distance (single pitch) l _{1 to} l ₇ between the centers of two circles 15 adjacent to each other, its dimensional accuracy, and the outermost optical fiber fixing engaging portion 11 located on the left side in the width direction of the optical fiber guide block 10. (Cumulative pitch) L ₁ to the center of the circle 15 virtually inserted into the
L ₇ and dimensional accuracy thereof, and the vertical distance (depth) d ₁ to d of the plane including the upper surface 16 of the end located in the width direction right and the center of the optical fiber fixing engaging portion 11 of each circle 15
₈ and its dimensional accuracy were determined.

In the same manner, the single pitch l _{1 of the} eight protrusions 3 a provided on the first molding portion 3 of the upper die 2 for forming the optical fiber fixing engagement portion 11 is formed. to l ₇ and dimensional accuracy thereof, the accumulated pitch L ₁ ~L
₇ and its dimensional accuracy, and the above vertical distance d ₁ to
The height of the portion corresponding to d ₈ (depth) and was determined its dimensional accuracy.

The design value of the single pitch l _{1 to} l ₇ is 250 for both the optical fiber fixing engaging portion 11 and the convex portion 3a formed on the first molded portion 3.
μm, and the above depth (height in the case of the convex portion 3a) d
The design value of _{1 to} d ₈ is 52.8 μm. Table 1 shows the measurement results.

[0093]

[Table 1]

As shown in Table 1, the dimensional accuracy of the single pitch, the cumulative pitch and the depth of the optical fiber guide block 10 is within ± 0.3 μm, and the obtained optical fiber guide block is The dimensional accuracy of 10, especially the dimensional accuracy of the optical fiber fixing engaging portion 11, is high. Then, the dimensional accuracy of the single pitches l _{1 to} l ₇ , the dimensional accuracy of the cumulative pitches L _{1 to} L ₇ , and the height d of the eight convex portions 3 a formed on the first molding portion 3 of the upper die 2. ₁
Dimensional accuracy of to d ₈ from it both is within ± 0.3 [mu] m, the molded under high transfer accuracy is made is confirmed. The single pitch, cumulative pitch, and height (depth) of the mold were corrected with respect to the target dimensions of the molded product. The above-mentioned correction value was determined in consideration of the difference in the coefficient of thermal expansion between the molding die and the material glass of the molded article.

In the same manner as in the case of obtaining the dimensional accuracy described above, the positional accuracy of the center of the vertical section of the optical fiber when the optical fiber is engaged with each optical fiber fixing engaging portion 11 ( Hereinafter, “position accuracy of the optical fiber center” is referred to as “optical fiber guide block 1”.
0 was determined with reference to the bottom surface or the side surface (the left side surface or the right side surface when viewed from the side surface 13 that is located at the optical connection side end surface when assembled into the optical fiber array). As a result, the positional accuracy is less than 2 μm for any optical fiber center when the bottom surface of the optical fiber guide block 10 is used as a reference, and for any optical fiber center when the side surface is used as a reference. It was within 3 μm. Therefore, the optical fiber guide block 1
The shape accuracy of 0 is high, including the outer shape accuracy.

The optical fiber guide block 10 having the above-described dimensional accuracy and shape accuracy has a quartz single-mode optical fiber having an outer diameter of 125 μm and a pitch of 250 μm.
The tape fibers (thickness is 400μ)
m) is suitable as a component of an optical fiber array for optical connection with an alignment accuracy of ± 1 μm.

Example 2 (1) Production of an optical fiber guide block First, a glass material having the same composition as that of the glass forming preform used in Example 1 was extruded hot, and a cross section in a direction perpendicular to the longitudinal direction was formed. A rod having a circular shape with a diameter of 3.05 mm is produced, and a flat surface having a width of 1 mm extending in the longitudinal direction of the rod is formed on a side surface of the rod by grinding. A 10.5 mm columnar glass preform was obtained. The cross-sectional shape and the size in the radial direction of the glass forming preform are substantially the same from the bottom surface to the upper surface, and the cross-sectional shape is a portion obtained by cutting out a part of a circle having a diameter of 3.05 mm. It takes the form of a 1 mm chord. The length of the cross section in the direction perpendicular to the chord is 2.97 mm. Further, the bottom surface and the top surface of the glass forming preform are each substantially flat. This glass forming preform is one of the glass forming preforms I of the present invention, and the glass forming preform satisfies the condition (i) described in the present invention.

Using the above glass forming preform as the glass forming preform and using the same mold as that used in Example 1 as the forming die, molding was performed in the same manner as in Example 1 to form an optical fiber guide block. Obtained. In performing the molding, the flat surface formed on the side surface of the glass forming preform was used as a rolling prevention part, and the glass forming preform and the lower mold were contacted by this plane. Similarly, the glass forming preform was placed in a forming die. Therefore, the maximum thickness of the glass forming preform in the state of being placed in the forming die is 2.9.
7 mm, which is 2.38 times the maximum thickness (1.25 mm) of the target optical fiber guide block. The shape of the optical fiber guide block thus obtained in plan view was substantially rectangular because the glass had sufficiently extended during molding.

(2) Measurement and evaluation of accuracy The optical fiber guide block obtained in (1) above was
The dimensional accuracy was measured in the same manner as in Example 1. As a result, the dimensional accuracy of each of the single pitch, the cumulative pitch, and the depth was all within ± 0.3 μm, and it was confirmed that the optical fiber had an engaging portion for fixing an optical fiber with high dimensional accuracy. Further, for the optical fiber guide block obtained in the above (1), the positional accuracy of the center of the optical fiber was measured in the same manner as in Example 1. As a result, the positional accuracy with respect to the bottom surface was within 5 μm, and the positional accuracy with reference to the side surface was within 3 μm, confirming high shape accuracy.

Example 3 (1) Production of Optical Fiber Guide Block First, a glass material having the same composition as the glass forming preform used in Example 1 was extruded hot and a cross section taken in a direction perpendicular to the longitudinal direction. The shape is 3.32 mm in major axis and 2.80 in minor axis.
A rod having an oval shape of mm was prepared, and the rod was cut into a predetermined length in a cold state to obtain a preform for forming an oval column-shaped glass having a height of 10.5 mm. The cross-sectional shape in the radial direction and the size of the glass forming preform are substantially the same from the bottom surface to the upper surface, and the cross-sectional shape has the same elliptical shape as the cross-sectional shape of the rod. Further, the bottom surface and the top surface of the glass forming preform are each substantially flat.
This glass forming preform is the glass forming preform II of the present invention.
It is one of.

Using the glass forming preform described above as the glass preforming body and using the same mold as that used in Example 1 as the molding die, molding was performed in the same manner as in Example 1 to form an optical fiber guide block. Obtained. In performing the molding, the glass forming preform was placed in the forming die such that the minor axis direction of the glass forming preform matched the vertical direction. Therefore, the maximum thickness of the glass forming preform in the state of being placed in the forming die is 2.80 m.
m, which is 2.24 times the maximum thickness (1.25 mm) of the target optical fiber guide block.
The shape of the optical fiber guide block thus obtained in plan view was substantially rectangular because the glass had sufficiently extended during molding.

(2) Measurement and Evaluation of Accuracy The optical fiber guide block obtained in (1) above was
The dimensional accuracy was measured in the same manner as in Example 1. As a result, the dimensional accuracy of each of the single pitch, the cumulative pitch, and the depth was all within ± 0.3 μm, and it was confirmed that the optical fiber had an engaging portion for fixing an optical fiber with high dimensional accuracy. Further, for the optical fiber guide block obtained in the above (1), the positional accuracy of the center of the optical fiber was measured in the same manner as in Example 1. As a result, the positional accuracy based on the bottom surface was within 4 μm, and the positional accuracy based on the side surface was within 5 μm, and it was confirmed that the device had high shape accuracy.

Example 4 (1) Production of Optical Fiber Guide Block First, a glass material having the same composition as that of the glass forming preform used in Example 1 was extruded hot to obtain a rod having a predetermined sectional shape. Obtained. The cross-sectional shape of this rod in a direction perpendicular to the longitudinal direction is a shape in which each corner of a regular hexagon having a side length of 1.68 mm is slightly rounded. Then
The rod is cut to a predetermined length in the cold, and the height is 10.5 mm.
, To obtain a columnar glass preform. The cross-sectional shape and the size of the glass forming preform in the radial direction are substantially the same from the bottom surface to the upper surface, and the cross-sectional shape is the same as the cross-sectional shape of the rod. Further, the bottom surface and the top surface of the glass forming preform are each substantially flat. This glass forming preform is one of the glass forming preforms I of the present invention, and the glass forming preform satisfies the conditions (i) and (ii) described in the present invention.

Using the above glass forming preform as the glass forming preform and using the same mold as that used in Example 1 as the molding die, molding was performed in the same manner as in Example 1 to form an optical fiber guide block. Obtained. When performing molding, one side (plane) of the glass forming preform
The glass forming preform was placed in the forming mold in the same manner as in Example 1 except that the glass forming preform and the lower mold contacted each other. Therefore, the maximum thickness of the glass forming preform in the state of being placed in the forming die is 2.91 mm, which is 2.33 of the maximum thickness (1.25 mm) of the target optical fiber guide block.
It is twice. The shape of the optical fiber guide block thus obtained in plan view was substantially rectangular because the glass had sufficiently extended during molding.

(2) Measurement and evaluation of accuracy The optical fiber guide block obtained in (1) above was
The dimensional accuracy was measured in the same manner as in Example 1. As a result, the dimensional accuracy of each of the single pitch, the cumulative pitch, and the depth was all within ± 0.3 μm, and it was confirmed that the optical fiber had an engaging portion for fixing an optical fiber with high dimensional accuracy. Further, for the optical fiber guide block obtained in the above (1), the positional accuracy of the center of the optical fiber was measured in the same manner as in Example 1. As a result, the positional accuracy based on the bottom surface was within 6 μm, and the positional accuracy based on the side surface was within 3 μm, and it was confirmed that the device had high shape accuracy.

Example 5 (1) Production of Optical Fiber Guide Block First, a glass material having the same composition as the glass forming preform used in Example 1 was extruded hot to obtain a rod having a predetermined sectional shape. Obtained. The cross-sectional shape of this rod in a direction perpendicular to the longitudinal direction is a shape in which each corner of a regular octagon with a distance between a pair of sides facing each other of 2.97 mm is slightly rounded. Next, the rod was cut into a predetermined length in a cold state to obtain a columnar glass preform having a height of 10.5 mm. The cross-sectional shape and the size of the glass forming preform in the radial direction are substantially the same from the bottom surface to the upper surface, and the cross-sectional shape is the same as the cross-sectional shape of the rod. Further, the bottom surface and the top surface of the glass forming preform are each substantially flat. This glass forming preform is one of the glass forming preforms I of the present invention, and the glass forming preform satisfies the condition (iii) described in the present invention.

Using the above glass forming preform as the glass forming preform and using the same forming die as used in Example 1 as the forming die, molding was performed in the same manner as in Example 1 to form an optical fiber guide block. Obtained. When performing molding, one side (plane) of the glass forming preform
The glass forming preform was placed in the forming mold in the same manner as in Example 1 except that the glass forming preform and the lower mold contacted each other. Therefore, the maximum thickness of the glass forming preform in the state of being placed in the forming die is 2.97 mm, which is 2.38 of the maximum thickness (1.25 mm) of the target optical fiber guide block.
It is twice. The optical fiber guide block thus obtained has a shape in plan view in which each corner of the rectangle is slightly rounded, but there is no practical problem.

(2) Measurement and evaluation of accuracy The optical fiber guide block obtained in (1) above was
The dimensional accuracy was measured in the same manner as in Example 1. As a result, the dimensional accuracy of each of the single pitch, the cumulative pitch, and the depth was all within ± 0.3 μm, and it was confirmed that the optical fiber had an engaging portion for fixing an optical fiber with high dimensional accuracy. Further, for the optical fiber guide block obtained in the above (1), the positional accuracy of the center of the optical fiber was measured in the same manner as in Example 1. As a result, the positional accuracy based on the bottom surface was within 4 μm, and the positional accuracy based on the side surface was within 5 μm, and it was confirmed that the device had high shape accuracy.

Comparative Example 1 (1) Production of Optical Fiber Guide Block First, a glass material having the same composition as that of the glass molding preform used in Example 1 was preliminarily hot-formed, and the ridges between the side surfaces, and the side surfaces and the upper surface. And a prismatic glass forming preform having a height of 10.0 mm, in which the ridges of the side and the side and the bottom have curved surfaces, respectively. The cross-sectional shape and the size in the radial direction of this glass forming preform are substantially the same from the bottom surface to the upper surface, and the cross-sectional shape is rectangular except for the point that the corners are rounded. The length of the cross section in the short direction is 2.5
0 mm, and the length in the longitudinal direction is 2.92 mm.

Using the above-mentioned glass forming preform as the glass forming preform and using the same forming die as used in Example 1 as the forming die, molding was performed in the same manner as in Example 1 to form an optical fiber guide block. Obtained. However, if the molding pressure was not set to 230 kg / cm ² or more, the filling of the glass into the thick portion having the optical fiber fixing engagement portion became insufficient. When performing the molding, the glass forming preform was placed in a molding die in the same manner as in Example 1 except that the longitudinal direction in the radial cross-sectional shape of the glass forming preform was set to coincide with the vertical direction. Was placed. Therefore, the maximum thickness of the glass forming preform in the state of being placed in the forming die is 2.92 mm, which is 2.33 of the target optical fiber guide block maximum thickness (1.25 mm). It is twice.

The optical fiber guide block thus obtained has a plan view shape in which the molding pressure is 160 kg / cm ^2, which is the same as that in Example 1, and the molding pressure is 23.
In any case where the pressure was 0 kg / cm ² or more, the glass was not uniformly stretched at the time of molding, and thus was slightly distorted.

(2) Measurement and evaluation of accuracy The optical fiber guide block obtained in (1) above was
The dimensional accuracy was measured in the same manner as in Example 1. As a result, the dimensional accuracy of each of the single pitch, the cumulative pitch, and the depth was all within ± 0.3 μm, and it was confirmed that the optical fiber had an engaging portion for fixing an optical fiber with high dimensional accuracy. Further, for the optical fiber guide block obtained in the above (1), the positional accuracy of the center of the optical fiber was measured in the same manner as in Example 1. As a result, the positional accuracy based on the bottom surface was within 10 μm, but the positional accuracy based on the side surface was measured because the shape of the optical fiber guide block was distorted as described above. It was impossible.

[0113]

As described above, according to the present invention,
It is possible to mold a thin plate-shaped molded product that requires a large flow of glass at the time of molding, such as a thin plate-shaped optical fiber fixing member with a large change in thickness such as a step, with high precision. The glass optical fiber fixing member can be mass-produced at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a molding die used in Example 1.

FIG. 2 is a perspective view schematically showing an optical fiber guide block obtained in Example 1.

FIG. 3 is a view for explaining measurement points of dimensional accuracy of the optical fiber guide block.

FIG. 4 is a cross-sectional view showing an example of a cross-sectional shape in the radial direction of a glass forming preform I satisfying a condition (i) according to the present invention.

FIG. 5 is a cross-sectional view showing another example of the cross-sectional shape in the radial direction of the glass forming preform I satisfying the condition (i) according to the present invention.

FIG. 6 is a cross-sectional view showing an example of a cross-sectional shape in the radial direction of a glass forming preform I satisfying the condition (ii) in the present invention.

FIG. 7 is a cross-sectional view showing an example of a cross-sectional shape in the radial direction of the glass forming preform I satisfying the condition (iii) according to the present invention.

[Explanation of symbols]

1 ... molding mold, 2 ... upper mold, 5 ... body mold, 7 ... lower mold,
8, 21, 31, 41 ... glass forming preform I, 10 ...
Optical fiber guide block, 11: optical fiber fixing engaging portion, 12: pedestal portion, 13: optical connection side end face.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiatsu Yokoo 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Inside Hoya Corporation

Claims (9)

[Claims] 1. A glass columnar shape having a polygonal cross section in a radial direction, a shape surrounded by two or more conic curves, or a shape surrounded by one or more straight lines and one or more conic curves. A glass molding preform, which satisfies one of the following conditions (i) to (iii): (i) The inner dimensions are the same as the glass forming preform, the cross-sectional shape in the radial direction is a rectangular frame, and each of the four inner side surfaces is in contact with the side surface or the ridge of the glass forming preform. When it is assumed that the glass forming preform is inserted into the cylindrical body, at least one of the four inner side surfaces of the cylindrical body comes into line contact with the side surface of the glass forming preform. (ii) Assuming that the glass forming preform has been inserted into the cylinder, 1 to 4 of the four inner side surfaces of the cylinder.
Three are in line contact with the ridges between the side surfaces of the glass forming preform, and the glass forming preform has four or more side surfaces. (iii) Assuming that the glass forming preform is inserted into the cylindrical body, the four inner side surfaces of the cylindrical body are in surface contact with the side faces of the glass forming preform, respectively, and The body has five or more sides. 2. A glass pillar having a radial cross-sectional shape surrounded by one conic curve,
(a) Used to obtain a thin plate-shaped molded product having a maximum thickness of 5 mm or less or (b) a molded product having a step portion whose height direction is substantially parallel to the pressing direction during molding. A glass forming preform characterized by the above-mentioned. 3. The glass forming preform according to claim 1, further comprising a rolling prevention portion. 4. A glass comprising glass containing SiO ₂ , B ₂ O ₃ and ZnO as glass components.
The glass forming preform according to claim 3. 5. As glass components, ₁ to 30 wt% of SiO ₂ , 15 to 40 wt% of B ₂ O ₃ , 40 to 60 wt% of ZnO (but not including 40 wt%), 0 to 15 wt% of MgO, 0 to 10% by weight of CaO, 0 to 10% by weight of SrO, 0 to 10% by weight of BaO, 0 to 20% by weight of PbO (However, the total amount of ZnO, MgO, CaO, SrO, BaO and PbO is 40 to 60% by weight ( but not included 40wt%.).), Al 2 O 3 and 0-10 wt% (provided that 0 wt% are not included.), contains, the total amount of the glass component is composed of 75 wt% or more glass, claim The glass forming preform according to any one of claims 1 to 4. 6. A molding die having a cavity of a predetermined shape such that the glass forming preform according to claim 1 or 2 is positioned such that a side surface of the glass forming preform is positioned in a pressing direction during molding. Wherein the glass molding preform is heated to a temperature at which the glass forming preform can be molded and molded into an optical fiber fixing member. 7. The method according to claim 6, wherein a glass forming preform having an anti-rolling part is used. 8. The method according to claim 6, wherein a glass preform made of glass containing SiO ₂ , B ₂ O ₃ and ZnO as a glass component is used. As 9. glass component, the _{SiO 2 1~30wt%, B 2 O} 3 and 15 to 40 wt%, the ZnO 40~60wt% (not including where 40wt%.), 0~15wt% of MgO, 0 to 10 wt% of CaO, 0 to 10 wt% of SrO, 0 to 10 wt% of BaO, 0 to 20 wt% of PbO (however, the total amount of ZnO, MgO, CaO, SrO, BaO and PbO is 40 to 60 wt% ( However, 40 wt% is not included.)), Al ₂ O ₃ is 0-10 wt% (however, 0 wt% is not included), and the glass forming reserve is made of glass containing 75 wt% or more of the above glass components. 9. The method according to any one of claims 5 to 8, wherein a body is used.