JP2002087828A - Method for manufacturing glass microdrop, method and device for manufacturing micro glassware using the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing a glass micro drop and micro glassware at a low cost and with high productivity. SOLUTION: The method for manufacturing the glass micro drop 3 includes heating of a top end part of glass fiber 1 to liquefy and dropping of the liquefied top end part. The method for manufacturing the micro glassware includes cooling of the glass micro drop 3 obtained by the method described above to solidify or molding the drop by receiving in a metallic mold (a receiving member) 4. The manufacturing device of the micro glassware is distinguished by containing the glass fiber 1, a heating member 2 for heating the top end part of the glass fiber 1 to drop the glass micro drop 3, the receiving member 4 for receiving the dropped glass micro drop 3, a means for moving the glass fiber 1 downwards or a means for moving the heating member 2 upwards and arranging the heating member 2 so as to assure dropping passage of the dropped glass micro drop 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing glass microdroplets, a method for producing microglass products using the method, and an apparatus for producing microglass products.

[0002]

2. Description of the Related Art Microscopic glass optical elements such as a collimator lens for optical communication, an optical pickup lens, and an endoscope lens have been manufactured by polishing in the old days. It was manufactured by such a method.

[0003] A method in which a glass material having an approximate shape is heated and press-molded on a mold. A method in which molten glass droplets are dropped on a heated mold and pressed. A method of manufacturing a spherical lens by cooling and solidifying a molten glass droplet.

[0004]

However, when an optical element having a small diameter (for example, about 0.5 to 3 mm) is manufactured by the above-described method, there are the following problems. That is, in the method (1), it is necessary to prepare a minute molding glass material having a volume corresponding to a desired optical element in advance, and it is difficult to process the material and the cost is high. Alternatively, after forming a relatively large volume glass material, a process of removing excess peripheral portions of the material by machining is required, which is costly.

In the methods (1) and (2), the molten glass droplet is usually dropped from a nozzle.
Since it is difficult to obtain a small molten glass droplet of m or less, a step of removing an extra peripheral portion after molding is required, and the cost is high.

The weight of a glass droplet dropped from a nozzle is generally expressed by the following equation (1). mg = 2πrγ (Equation 1) (m: Drop weight, g: Gravitational acceleration, r: Nozzle tip outer diameter (radius), γ: Drop surface tension) (I) According to the above equation, the nozzle tip outer diameter is small. Then, the weight of the glass droplet can be reduced, but in reality, it is necessary to secure a constant inner diameter in order to flow the molten glass into the nozzle, and there is a limit to reducing the outer diameter. (II) Since the molten glass spreads wet at the nozzle tip and the apparent nozzle outer diameter becomes larger, even if the outer diameter is made smaller than a certain value, the effect of reducing the outer diameter by making the outer diameter smaller can be reduced. Can not be obtained.

An object of the present invention is to provide a method and an apparatus for producing glass microdroplets and microglass products at low cost and with good productivity.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for producing glass microdroplets, comprising heating a glass fiber tip to liquefy it, and dropping the liquefied tip.

The present invention also relates to a method for producing a micro glass product, which comprises cooling and solidifying the glass micro droplets obtained by the above method or receiving and molding the glass micro droplets in a mold.

[0010] The present invention also provides a glass fiber, a heating member for heating the tip of the glass fiber to cause the glass microdroplets to drop, a receiving member for receiving the dropped glass microdroplets, and lowering the glass fiber. Manufacturing a micro glass product, comprising means for moving or a means for moving the heating member upward, wherein the heating member is arranged so as to secure a falling path of the dropped glass micro droplets. Related to the device.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a glass microdroplet and a microglass product of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of an example of an apparatus for manufacturing a micro glass product employing the method of the present invention.

The apparatus shown in FIG. 1 comprises a glass fiber 1, a heating member 2 for heating the tip of the glass fiber to drop the glass droplets 3, and a receiving member 4 for receiving the dropped glass droplets 3. And means for moving the glass fiber downward (hereinafter simply referred to as downward moving means) (not shown) or means for moving the heating member upward (hereinafter simply referred to as upward moving means) (not shown)
Comprising.

The glass fiber 1 is not particularly limited as long as it is a linear body made of a glass material capable of forming a desired glass product. As such a glass material, for example, SF57,
LaF71, SK5, LaK8, PKS1 and the like can be exemplified. Further, the glass fiber 1 may be manufactured by any method as long as the glass fiber 1 is made of the above glass material,
For example, it may be manufactured by drawing a melt of the above glass material from a nozzle and cooling while mechanically stretching, or a solution of a glass raw material such as a metal alkoxide capable of producing the above glass material from a nozzle. It may be manufactured by drawing and heating.

The wire diameter (radius) of the glass fiber 1 is not particularly limited, and may be determined by Equation 2 according to the weight of the target fine glass droplet. In the present invention, since the weight of the obtained glass droplet complies with the following equation 2, it is possible to easily change the weight of the glass droplet and the glass product by changing the diameter of the glass fiber. mg = 2πr′γ (Equation 2) (m: drop weight, g: gravitational acceleration, r ′: glass fiber wire diameter (radius), γ: drop surface tension)

For example, when producing glass microdroplets (spherical, SF57) having a diameter of φ0.9-2.2 mm, the radius is about 0.05-0.
8 mm glass fiber may be used.

The heating member 2 is a known heating source capable of liquefying the tip portion of the glass fiber and raising the temperature to a temperature at which the tip portion can be dropped. Are located. The heating member 2 in FIG. 1 has a ring shape, and is arranged so that the glass fiber can be inserted into the inside of the member in the vertical direction. It may be arranged vertically around. By disposing the heating member in such a manner, the tip of the glass fiber is uniformly liquefied in the circumferential direction, and it is possible to effectively suppress the variation in weight during continuous production of glass microdroplets. In the present invention, it is preferable to adopt the arrangement configuration of the glass fiber and the heating member as shown in FIG. In the present invention, as long as the tip of the glass fiber is liquefied and the tip can be dripped, it does not prevent the one heating member from being arranged away from the glass fiber shaft.

The heating member 2 only needs to be able to raise the temperature to a temperature at which the glass fiber is softened and liquefied and has a viscosity that allows dripping from the tip. The temperature varies depending on the type of glass, but is usually in the range of 500 ° C to 1500 ° C. The heating method may be any method, for example, a cartridge heater, a high-frequency induction heating, an infrared heating, or the like.

In the present invention, first, the tip of the glass fiber is heated and liquefied. In FIG. 1, the tip of the glass fiber 1 is brought closer to the heating member 2 that has been heated in advance by a downward moving unit (not shown).
The heating member 2 heated in advance may be brought closer to the tip of the glass fiber 1 by an upward moving means (not shown). In particular, when a ring-shaped heating member is used, the glass fiber 1
Is preferably moved downward gradually by a downward moving means (not shown).

The set temperature of the heating member is a temperature at which the tip of the glass fiber can be liquefied and the liquefied tip can drip. In general, if the glass temperature is too high, foaming or the like tends to occur, and if the glass temperature is too low, devitrification tends to occur. Therefore, an appropriate temperature may be selected according to the glass material. Specifically, for example, the heating member has a ring shape with an inner diameter of 10 mm, the glass fiber is made of SF57, and the wire diameter (radius) is about 0.05 to 0.8 mm
At this time, the heating member is set at about 850 ° C.

The upward moving means may be any device capable of moving the heating member stepwise or steplessly, preferably steplessly, at a speed of about 0.1 to 5 mm / sec. The downward moving means is an apparatus capable of moving the glass fiber steplessly at the same speed as the above means.

The liquefied tip portion becomes spherical due to surface tension, and when the weight of the glass droplet exceeds the surface tension, the glass droplet separates from the fiber and drops. After the first glass droplet is dropped, if the glass fiber is continuously moved further downward, or the heating member is continuously moved further upward, the glass minute droplet can be easily and continuously. Can be manufactured. The moving speed may be a speed at which the glass fiber is shortened by the formation and dropping of the glass microdroplets.

In the present invention, a micro glass product can be easily obtained by applying the glass micro droplets obtained as described above to a known glass product manufacturing method. For example, the dropped glass microdroplets can be cooled and solidified, or can be received in a mold and molded to obtain a microglass product. In the present specification, the term “glass product” is used in a concept that includes a final product that does not require subsequent processing and an intermediate product that requires subsequent processing. As final products, for example, optical communication collimator lens,
Examples include a small glass optical element such as an optical pickup lens, an endoscope lens, a fiber coupling microsphere lens, and a small digital camera lens. Examples of the intermediate product include a fine glass material (preform) for press molding.

That is, by cooling and solidifying the dropped glass microdroplets, a microsphere lens as a final product may be obtained, or a microglass material as an intermediate product may be obtained. The cooling means is not particularly limited, but can be easily cooled at a low cost by securing a sufficient dropping distance, and can be cooled and solidified at low cost. The falling distance depends on the weight (size) of the glass microdrops.
When obtaining glass products of 3mm or less, usually 200-1000mm
Is desirable.

Also, a member for receiving the dropped glass microdroplets.
By receiving at 4 and press molding, a micro glass optical element as a final product may be obtained, or a micro glass material as an intermediate product may be obtained. It is preferable to use a mold as the receiving member 4 from the viewpoint of further improving the productivity.

For example, glass microdroplets are received by a heated lower mold, conveyed to below a pair of upper molds, and prepress-molded by upper and lower molds, thereby forming a fine glass material as an intermediate product. Obtainable. At this time, the minute glass material can be obtained also by receiving the glass minute droplets with the lower mold and cooling as it is without using the upper mold. The obtained micro glass material may be used as a micro glass optical element as a final product.

Further, for example, a glass microdroplet is received by a heated lower mold, conveyed to below a pair of upper molds, and press-formed by upper and lower molds to form a microglass optical element as a final product. Obtainable. The shape of the lower mold and the upper mold is appropriately set to be planar, concave or convex,
An optical element having a desired shape and surface accuracy can be obtained by appropriately selecting the surface accuracy of the mold forming surface. The obtained micro glass optical element may be used as a micro glass material as an intermediate product.

The case where the present invention is applied to the production of glass microdroplets and microglass products has been described above.
The present invention is not limited to this, and can be applied to the production of relatively large glass droplets and glass products by setting the wire diameter of the glass fiber to be relatively large and optimizing other conditions. It is clear.

[0028]

Embodiment (Embodiment 1) A description will be given with reference to FIG. The tip of the glass fiber (SF57) 1 was heated by a ring heater 2 set at a heater temperature of 850 ° C. Specifically, when the glass fiber 1 was gradually sent downward toward the inside of the ring heater 2, the glass at the tip became liquefied and became spherical due to surface tension. When the weight of the glass droplet exceeded the surface tension, the glass droplet separated from the fiber and dropped. The falling distance was 500 mm. When glass droplets were dropped at various glass fiber diameters, microsphere glass having a weight and a droplet diameter as shown in Table 1 could be obtained.

[0029]

[Table 1]

(Embodiment 2) By receiving the glass microdroplets dropped in the same manner as in Embodiment 1, by using a tray installed sufficiently below, the glass balls can be cooled and solidified while falling, and a microsphere lens can be obtained. Was. This lens can also be used as a molding glass material for obtaining a more precise shape.

(Example 3) Glass microdroplets dropped in the same manner as in Example 1 are dropped on a lower mold (flat surface) heated to 400 ° C, and then to a position below a pair of upper molds (convex). When the mold was moved and press-molded with upper and lower molds, a fine glass lens (flat-concave shape) with a good transfer of the mold shape could be obtained. The falling distance was 100 mm. This micro glass lens can also be used as a material for press molding for molding into a more precise shape.

[0032]

According to the method and apparatus of the present invention, glass microdroplets of φ3 mm or less, which are difficult to drop by ordinary nozzles, can be produced at low cost and with high productivity. Further, by applying the obtained glass microdroplets to a known method for manufacturing a microscopic glass product, various microscopic glass products can be manufactured at low cost and with high productivity. Further, it is possible to easily change the weight (size) of the glass droplet and the glass product by changing the wire diameter of the glass fiber.

[Brief description of the drawings]

FIG. 1 shows a schematic cross-sectional view of an apparatus for producing glass microdroplets or microglass products employing the method of the present invention.

[Explanation of symbols]

1; glass fiber, 2; ring heater, 3; glass microdrop, 4; receiving member.

Claims (4)

[Claims] 1. A method for producing glass microdroplets, comprising heating a tip portion of a glass fiber to liquefy it, and dropping the liquefied tip portion. 2. A method for producing a micro glass product, comprising cooling and solidifying glass micro droplets obtained by the method according to claim 1. 3. A method for producing a micro glass product, comprising receiving a glass micro droplet obtained by the method according to claim 1 in a mold and molding. 4. A glass fiber, a heating member for heating the tip of the glass fiber to drop glass microdroplets, a receiving member for receiving the dropped glass microdroplets, and moving the glass fiber downward. Or means for moving the heating member upward,
An apparatus for manufacturing a micro glass product, wherein the heating member is arranged so as to secure a falling path of the dropped glass micro droplet.