JP2003137568A - Apparatus for molding glass element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen life of an apparatus and to stabilize a molding condition by controlling temperature of a reflection mirror to reflect light and heat from an infrared lamp. SOLUTION: An apparatus for molding glass element is equipped with a pair of molds 6, 13 at which a glass base material 32 is placed, an infrared lamp 20 to heat the molds and the glass base material, a fixed shaft 2 a driving device 8 and a moving shaft 9 to form a glass element by pressing the heated glass material, a reflection mirror 21 to reflect light and heat from the lamp to the direction of the molds and the glass base material, a cooling plate 33, a cooling tube 34 and a chiller 35 to cool the reflection mirror by a cooling liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass element molding apparatus having an improved cooling means for a reflecting mirror that reflects light generated from an infrared lamp for heating.

[0002]

2. Description of the Related Art Methods for manufacturing glass elements such as glass lenses, which require high precision, are roughly classified into two types: those manufactured by grinding / polishing and those manufactured by reheat pressing.

Generally, as a method of manufacturing an optical glass element, a method of grinding and polishing a glass material to form an optical surface is often used. However, in addition to requiring more than ten steps to form a curved surface by grinding and polishing, there is the problem that a large amount of glass grinding powder, which is harmful to the operator, is generated.
There is a problem that it is difficult to manufacture a large number of glass lenses having an aspherical optical surface with high added value with the same accuracy.

On the other hand, in the reheat press, the glass material produced by cooling the molten glass once is heated and pressed to transfer the shape of the mold to the glass material,
It is a method of molding glass elements such as glass lenses,
There is an advantage that the step required for forming the curved surface is only one step of press molding. Further, once the mold is manufactured, it is possible to manufacture many molded products according to the precision of the mold.

In order to extend the life of the mold, the atmosphere around the mold is preferably an inert atmosphere or a vacuum atmosphere.

[0006]

In recent years, glass elements have received a great deal of attention in the fields of optical communication and medical care. Above all, a silica glass element has been attracting attention because of its small thermal expansion, few impurities, and good ultraviolet transmittance.
Therefore, various glass elements such as a microlens array having a complicated shape and a variety of sizes from a very small size to a large size are required.

In the reheat press, a glass material is placed between the molds, the molding chamber containing the mold and the glass material is placed in an inert gas atmosphere for the purpose of preventing the mold from being oxidized, and then heated by an infrared lamp or the like. After pressing the material with a mold, the molded product is cooled and taken out.
In order to increase the efficiency of the infrared lamp, a reflection mirror having a high infrared reflectance is required around the infrared lamp so that the infrared rays do not easily leak to a place other than the mold or the glass material that needs to be heated. However, in the case of press-molding a glass material such as quartz glass having a high molding temperature of about 1400 ° C., when the glass material is heated, the temperature of the reflecting mirror may rise and the mirror may be damaged. Further, when the layer on the surface of the reflection mirror is deteriorated, the reflection efficiency is lowered and there is a risk that the molding conditions are changed.

Therefore, the present invention provides a glass element molding apparatus which prevents overheating of a reflection mirror when a glass element is molded by a reheat press, thereby prolonging the life of the apparatus and stabilizing molding conditions. It is in.

[0009]

In order to achieve the above object, the present invention has the following constitution.

(1) A pair of molds for arranging a glass material, an infrared lamp for heating the mold and the glass material, pressing means for pressing the heated glass material into a glass element, and light heat of the infrared lamp. A glass element molding apparatus, comprising: a reflection mirror that reflects the light in the direction of the mold and the glass material; and a cooling unit that cools the reflection mirror with a cooling liquid.

(2) A circulation path of a cooling liquid for cooling the reflection mirror, a cooling liquid cooling device arranged in this circulation path, a temperature sensor embedded in the reflection mirror, and a temperature detection signal from the temperature sensor. And a control unit for controlling the cooling temperature of the cooling liquid by the cooling device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a molding apparatus. In this apparatus, a fixed shaft 2 extends downward from an upper portion of a frame 1, and an upper mold assembly 4 is attached to a lower end of the fixed shaft 2 via a ceramic heat insulating cylinder 3 by a bolt or the like not shown. The upper die assembly 4 includes a die plate 5 made of metal, ceramic, or carbon, an upper die 6 made of ceramic, cemented carbide, or the like, and the upper die 6 being a die plate 5.
It consists of a fixed die 7 which is attached to and forms part of the mould.

A drive device 8 such as a screw jack for converting a rotational motion of the servo motor 8a into a linear motion thrust is provided below the frame 1 by using a servo motor 8a as a drive source. The drive device 8 includes a load detection device 8b. A moving shaft 9 is attached via. The moving shaft 9 moves up and down so that speed, position and torque can be controlled by a program input to the control device 27, and extends upward facing the fixed shaft 2. A heat insulating cylinder 10 similar to the heat insulating cylinder 3 is attached to the upper end of the moving shaft 9. The lower die assembly 11 includes a die plate 12, a lower die 13 and a moving die 14.

A bracket 15 that is moved up and down by a driving device (not shown) is movably connected to the fixed shaft 2. The bracket 15 includes a transparent quartz glass tube 16 with a flange and an outer cylinder 18 that surround the pair of mold assemblies 4 and 11.
And a lamp unit 19 is attached to the outer cylinder 18. The lamp unit 19 includes an infrared lamp 20 and a reflection mirror 21 arranged behind the infrared lamp 20, and heats the mold assemblies 4 and 11.

The glass material 3 is placed between the upper and lower molds 6 and 13.
2 is arranged, the moving shaft 9 is raised by the drive device 8,
A glass element heated to a desired temperature is press-formed to form a glass element having a desired thickness and shape.

As shown in FIG. 2, the apparatus further includes a cooling plate 33 for cooling the reflection mirror 21 and a cooling pipe 34 for cooling the cooling plate. Cooling pipe 3
Reference numeral 4 circulates between a cooling plate and a cooling device (chiller) 35. The cooling liquid passing through the inside of the cooling pipe is cooled by the cooling device 35 and is circulated and used. The temperature of the cooling liquid discharged from the cooling device 35 is measured by a temperature sensor 36 embedded in the reflection mirror 21, and based on the temperature instruction value, a temperature control device 37 sets a desired temperature, for example, 15 ° C.
Controlled by. In this way, the infrared lamp 20
The temperature of the reflection mirror 21 can be controlled so as not to overheat by cooling the reflection mirror 21 that reflects the light heat of No. 2 with a cooling liquid and cooling the used cooling liquid with a chiller for reuse. Also, the reflection mirror 2
It is possible to control the coolant temperature by reading the temperature of 1 with the temperature sensor 36, comparing the value with the ideal temperature (set value), and applying temperature feedback to the chiller. This makes it possible to prevent the reflection mirror 21 from being damaged and extend the life of the device. Further, it is possible to prevent the molding conditions from changing due to deterioration of the reflection mirror 21.

Returning to FIG. 1, the upper end of the transparent quartz glass tube 16 with a flange is in airtight contact with the O-ring fitted in the bracket 15. Also, a transparent quartz tube with a flange 1
The lower end of 6 is brought into air-tight contact with the O-ring of the intermediate plate 1a through which the moving shaft 9 penetrates to form a molding chamber 17 around the mold assemblies 4 and 11 which is shielded from the atmosphere.

Fixed shaft 2, movable shaft 9 and bracket 15
Includes gas supply passages 22 and 23 for forming an inert gas atmosphere in the molding chamber 17 and cooling the mold assembling 4, 11.
Is provided, and via a flow control meter (not shown),
The inert gas is supplied to the molding chamber 17 at a predetermined flow rate. The inert gas supplied to the molding chamber 17 is exhausted from the gas exhaust passage 24. In the figure, reference numeral 25 is a vacuum exhaust port, 26 is a thermocouple for temperature detection of the lower mold assembly 11, 27 is a control unit, 28 is a vacuum valve, 29 is a gas exhaust valve, 30 is a vacuum exhaust device, and 31 is It is a vacuum gauge.

[0020]

As described above, according to the glass element molding apparatus of the present invention, the reflection mirror that reflects the light heat from the infrared lamp is cooled by the cooling liquid, and the warmed cooling liquid is cooled by the cooling device. Since the cooling liquid is circulated again to the reflecting mirror later, the temperature of the reflecting mirror that reflects the light heat of the infrared lamp can be controlled even when molding high-melting glass such as quartz glass, and the life of the device is long. It is possible to stabilize the molding conditions and molding conditions.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an optical element molding apparatus according to the present invention.

FIG. 2 is a detailed view around an infrared lamp of the optical element molding apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Frame, 2 ... Fixed shaft, 3 ... Heat insulation cylinder, 4 ... Upper mold assembly, 5 ... Die plate, 6 ... Upper mold, 7 ... Fixed die, 8
... Drive device, 8a ... Servo motor, 8b ... Load detector,
9 ... Moving shaft, 10 ... Insulating cylinder, 11 ... Lower mold assembly, 12
... die plate, 13 ... lower mold, 14 ... moving die, 15 ...
Bracket, 16 ... Quartz glass tube, 17 ... Molding chamber, 18
... Outer cylinder, 19 ... Lamp unit, 20 ... Infrared lamp,
21 ... Reflective mirror, 22, 23 ... Gas supply path, 24 ... Gas exhaust path, 25 ... Vacuum exhaust port, 26 ... Temperature detecting thermocouple, 27 ... Control device section, 28 ... Vacuum valve, 29 ... Gas exhaust valve, 30 ... Vacuum exhaust device, 31 ... Vacuum gauge, 32
... glass material, 33 ... cooling plate, 34 ... cooling pipe, 35 ... cooling device (chiller), 36 ... temperature sensor, 37 ... temperature control device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shusaku Matsumura             2068 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd.             In the company F-term (reference) 2H042 DB04 DB13 DD05 DE06                 3K058 AA41 AA42 AA45 BA00 EA03                       EA23

Claims (2)

[Claims] 1. A pair of molds on which a glass material is arranged, an infrared lamp for heating the mold and the glass material, a pressing means for pressing the heated glass material into a glass element, and a light heat of the infrared lamp. A glass element molding apparatus, comprising: a reflection mirror that reflects the light in the direction of the mold and the glass material; and a cooling unit that cools the reflection mirror with a cooling liquid. 2. A circulation path of a cooling liquid for cooling the reflection mirror, a cooling liquid cooling device arranged in the circulation path, a temperature sensor embedded in the reflection mirror, and a temperature detection signal from the temperature sensor. The control device for controlling the cooling temperature of the cooling liquid by the cooling device, and the glass element molding device according to claim 1.