JP3068261B2 - Glass optical element molding method - Google Patents
Glass optical element molding methodInfo
- Publication number
- JP3068261B2 JP3068261B2 JP3204943A JP20494391A JP3068261B2 JP 3068261 B2 JP3068261 B2 JP 3068261B2 JP 3204943 A JP3204943 A JP 3204943A JP 20494391 A JP20494391 A JP 20494391A JP 3068261 B2 JP3068261 B2 JP 3068261B2
- Authority
- JP
- Japan
- Prior art keywords
- glass material
- temperature
- glass
- molding
- heating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000011521 glass Substances 0.000 title claims description 72
- 238000000465 moulding Methods 0.000 title claims description 32
- 238000000034 method Methods 0.000 title claims description 18
- 230000003287 optical effect Effects 0.000 title claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 60
- 239000000463 material Substances 0.000 claims description 56
- 238000003825 pressing Methods 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- 239000012778 molding material Substances 0.000 claims 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 19
- 229910001873 dinitrogen Inorganic materials 0.000 description 15
- 239000007789 gas Substances 0.000 description 8
- 230000009477 glass transition Effects 0.000 description 4
- 239000005308 flint glass Substances 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 239000011800 void material Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
- C03B11/06—Construction of plunger or mould
- C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
- C03B11/12—Cooling, heating, or insulating the plunger, the mould, or the glass-pressing machine; cooling or heating of the glass in the mould
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B40/00—Preventing adhesion between glass and glass or between glass and the means used to shape it, hold it or support it
- C03B40/04—Preventing adhesion between glass and glass or between glass and the means used to shape it, hold it or support it using gas
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2215/00—Press-moulding glass
- C03B2215/40—Product characteristics
- C03B2215/46—Lenses, e.g. bi-convex
- C03B2215/47—Bi-concave
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2215/00—Press-moulding glass
- C03B2215/72—Barrel presses or equivalent, e.g. of the ring mould type
- C03B2215/73—Barrel presses or equivalent, e.g. of the ring mould type with means to allow glass overflow in a direction perpendicular to the press axis
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明は加熱軟化したガラス素材
を成形型で押圧して所定形状のガラス光学素子に成形す
る方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a glass optical element having a predetermined shape by pressing a heat-softened glass material with a mold.
【０００２】[0002]
【従来の技術】薄肉部と厚肉部との肉厚差が大きなガラ
ス光学素子をプレスにより成形する方法としては、従
来、特開平２−５５２３５号公報および特開平２−１３
３３２５号公報に記載された方法が知られている。特開
平２−５５２３５号公報の方法は、一対の凸面成形型と
胴型からなる成形型における熱源に接する部分にくり抜
き部を形成し、この成形型を使用して凹形状レンズの光
学面部中心の温度を非光学面部の温度よりも高く保ちつ
つ冷却加圧している。この方法は、成形型のくり抜き部
により、空気断熱層が構成されることで、加圧冷却時に
収縮量の小さいレンズ光学面中心の温度を高く保ち、収
縮量の大きい非光学面側との収縮差を縮めながら冷却す
ることにより、形状精度の良好な高精度のレンズを形成
することを目的としている。2. Description of the Related Art As a method of molding a glass optical element having a large difference in thickness between a thin portion and a thick portion by pressing, a conventional method is disclosed in JP-A-2-55235 and JP-A-2-13.
A method described in 3325 is known. In the method disclosed in JP-A-2-55235, a hollow portion is formed at a portion in contact with a heat source in a mold including a pair of convex molds and a body mold, and the center of the optical surface portion of the concave lens is formed using the mold. The cooling and pressurizing is performed while maintaining the temperature higher than the temperature of the non-optical surface portion. In this method, the air heat insulating layer is formed by the hollow portion of the molding die, so that the temperature at the center of the lens optical surface with a small amount of shrinkage during pressure cooling is kept high, and the shrinkage with the non-optical surface side with a large amount of shrinkage is maintained. An object is to form a high-precision lens with good shape accuracy by cooling while reducing the difference.
【０００３】一方、特開平２−１３３３２５号公報の方
法は、ガラス素材の厚肉部よりも薄肉部が高温度となる
ように加熱した後、金型で押圧成形してする。これによ
り、金型による押圧成形時に厚肉部と薄肉部との温度差
がなくなるため、ヒケの生じないレンズを成形すること
を目的としている。On the other hand, in the method disclosed in Japanese Patent Application Laid-Open No. 2-133325, a thin portion of a glass material is heated so as to have a higher temperature than a thicker portion, and then pressed by a metal mold. This eliminates the temperature difference between the thick portion and the thin portion at the time of press-molding with a mold, and aims to mold a lens that does not cause sink marks.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら特開平２
−５５２３５号公報の方法は型のくり抜き部の断熱機能
が十分でないため、厚肉部と薄肉部の肉厚比が２．５：
１以上の偏肉の大きなレンズや薄肉部が２ｍｍ以下のレ
ンズでは、ガラス素材の薄肉部が成形型の両方の型から
急冷される。このため薄肉部が急激に固化して厚肉部と
の収縮差が生じ、目的とする精度の良好なレンズを成形
することができない問題があった。SUMMARY OF THE INVENTION
According to the method disclosed in JP-A-55235, the thickness ratio between the thick portion and the thin portion is 2.5:
In one or more lenses having a large thickness deviation or a lens having a thin portion of 2 mm or less, the thin portion of the glass material is rapidly cooled from both molds. For this reason, there has been a problem that the thin portion is rapidly solidified and a difference in shrinkage from the thick portion is generated, so that it is impossible to mold a lens having the desired accuracy.
【０００５】また、特開平２−１３３３２５号公報の方
法では、厚肉部に比べて体積が小さな薄肉部の熱が成形
型に急速に奪われるため、肉厚比が２．５：１以上の偏
肉の大きなレンズや薄肉部が２ｍｍ以下のレンズでは薄
肉部をかなり高温に加熱しなければヒケの除去が難し
い。しかも、このような温度差を有した加熱の制御が難
しく、結果としてレンズにヒケを生じていた。In the method disclosed in Japanese Patent Application Laid-Open No. 2-133325, the heat of a thin portion having a smaller volume than that of a thick portion is quickly taken away by a molding die. In a lens having a large uneven thickness or a lens having a thin portion of 2 mm or less, it is difficult to remove sink marks unless the thin portion is heated to a considerably high temperature. In addition, it is difficult to control the heating having such a temperature difference, and as a result, sink occurs in the lens.
【０００６】本発明は上記事情を考慮してなされたもの
であり、肉厚比２．５：１以上の偏肉の大きな形状や薄
肉部が２ｍｍ以下の形状のレンズであっても形状精度が
良好で、ヒケを生じることのないガラス光学素子の成形
方法を提供することを目的とする。The present invention has been made in consideration of the above circumstances, and the shape accuracy is large even in a lens having a large uneven thickness having a thickness ratio of 2.5: 1 or more and a lens having a thin portion having a thickness of 2 mm or less. An object of the present invention is to provide a method for forming a glass optical element which is favorable and does not cause sink marks.
【０００７】[0007]
【課題を解決するための手段】本発明のガラス光学素子
の成形方法は、加熱軟化したガラス素材を成形面を有し
た一対の成形型で押圧成形した後、冷却する成形方法に
おいて、加熱軟化したガラス素材を前記成形型の下型に
載置する工程と、ガラス素材の上面形状を反転させた表
面形状を有する加熱部材を前記ガラス素材の上面に接近
させながらガラス素材と加熱部材との間の空隙に加熱気
体を供給する工程と、前記加熱部材を前記ガラス素材の
上面から退避させた後、ガラス素材の上面に成形型の上
型を接触させてガラス素材を押圧成形する工程とを備え
ていることを特徴とする。According to the method of molding a glass optical element of the present invention, a heat-softened glass material is press-molded with a pair of molds having molding surfaces, and then heated and softened. A step of placing the glass material on the lower die of the molding die, and moving the heating member having a surface shape obtained by inverting the upper surface shape of the glass material between the glass material and the heating member while approaching the upper surface of the glass material. A step of supplying a heating gas to the gap, and a step of, after retracting the heating member from the upper surface of the glass material, contacting the upper mold of the molding die with the upper surface of the glass material to press-mold the glass material. It is characterized by being.
【０００８】また、この方法では、前記加熱部材は前記
ガラス素材の薄肉部を厚肉部よりも高温とする温度分布
を有して加熱することができる。Further, in this method, the heating member can be heated with a temperature distribution such that a thin portion of the glass material has a higher temperature than a thick portion.
【０００９】[0009]
【作用】加熱軟化状態で下型に載置されたガラス素材
は、その上面に近接した加熱部材との間に流入した加熱
気体の圧力により、下型の成形面に押し当てられなが
ら、上面から熱を受けることによって下面側のガラスの
流動を進行あるいは完了させた状態で薄肉部の粘度上昇
（固化）を遅延させることができる。そして、前記加熱
部材をガラス素材の上面より退避させた後、上型を接触
させて押圧成形することにより、ガラスの流動が完了す
るとともに冷却され、形状精度の良好な成形品が得られ
る。この場合、加熱部材及び加熱された気体による加熱
効果を任意に制御することによって、薄肉部の粘度上昇
をさらに効果的に遅延させることができる。The glass material placed on the lower mold in the heat-softened state is pressed from the upper surface while being pressed against the molding surface of the lower mold by the pressure of the heating gas flowing between the heating member and the heating member adjacent to the upper surface. By receiving the heat, the viscosity rise (solidification) of the thin portion can be delayed in a state where the flow of the glass on the lower surface side is advanced or completed. Then, after the heating member is retracted from the upper surface of the glass material, the upper mold is brought into contact with the glass material to perform press molding, whereby the flow of the glass is completed and the glass is cooled, so that a molded product having good shape accuracy is obtained. In this case, by arbitrarily controlling the heating effect by the heating member and the heated gas, the increase in the viscosity of the thin portion can be more effectively delayed.
【００１０】[0010]
【実施例１】図１および図２は本発明が適用される成形
装置を示し、加熱炉３と成形室４とが連設されている。
加熱炉３は円筒形状となっており、内部には電気ヒータ
３ａが設けられている。この電気ヒータ３ａは図示しな
い温度センサおよび温度コントローラによって任意の温
度に制御される。成形室４内には加熱部材５および下型
６とが設けられている。この加熱部材５および下型６は
図示しない駆動機構により同軸的に上下動自在となって
いる。下型６は耐熱性を有し、ガラスとの化学的結合性
が低く、しかも鏡面加工が可能なＳｉＣ，ＢＮ，Ｃｒ2
Ｏ3 などのセラミックスが使用され、その成形面６ａは
所望のレンズ形状に対応した形状に鏡面研磨されてい
る。Embodiment 1 FIGS. 1 and 2 show a molding apparatus to which the present invention is applied, in which a heating furnace 3 and a molding chamber 4 are connected to each other.
The heating furnace 3 has a cylindrical shape, and an electric heater 3a is provided inside. The electric heater 3a is controlled to an arbitrary temperature by a temperature sensor and a temperature controller (not shown). A heating member 5 and a lower mold 6 are provided in the molding chamber 4. The heating member 5 and the lower mold 6 can be moved up and down coaxially by a drive mechanism (not shown). The lower mold 6 has heat resistance, low chemical bonding to glass, and mirror-finished SiC, BN, Cr 2
A ceramic such as O 3 is used, and its molding surface 6a is mirror-polished to a shape corresponding to a desired lens shape.
【００１１】この下型６の外周面には加熱ヒータ６ｂが
巻回され、これにより図示しない温度センサ及び温度コ
ントローラにより、所定の温度に制御可能となってい
る。加熱部材５は例えば石英ガラスにより成形されてお
り、下端面の加熱面５ａはガラス素材１の上面１ａの形
状を反転させた曲率半径（例えばＲ＝１００ｍｍ）の凸
球面となっており、内部には電気ヒータ５ｂが加熱面５
ａの近傍に設置されている。この電気ヒータ５ｂは図示
しない温度センサ及び温度コントローラにより、任意の
温度に制御自在になっている。A heater 6b is wound around the outer peripheral surface of the lower die 6, so that a predetermined temperature can be controlled by a temperature sensor and a temperature controller (not shown). The heating member 5 is formed of, for example, quartz glass, and the heating surface 5a at the lower end surface is a convex spherical surface having a radius of curvature (for example, R = 100 mm) obtained by inverting the shape of the upper surface 1a of the glass material 1. Is the electric heater 5b is the heating surface 5
a. The electric heater 5b can be controlled to an arbitrary temperature by a temperature sensor and a temperature controller (not shown).
【００１２】また、加熱部材５の中央部には直径２ｍｍ
程度の流入穴を有した垂直方向に延びる筒状の導入管５
ｄが設けられている。導入管５ｄは石英ガラス等により
成形されており、その周囲には電気ヒータ５ｅが設置さ
れて、図示しない温度センサ及び温度コントローラによ
って任意の温度に制御自在になっている。この導入管５
ｄには図示しない窒素ガス供給装置から任意の圧力及び
流量の窒素ガス８が供給され、電気ヒータ５ｅにより、
所定の温度に加熱されながらガラス素材１と加熱部材５
との間の空隙７に流入できるようになっている。９は電
気ヒータ５ｂ，５ｅの背面側に位置するように加熱部材
５内に設けられた反射板である。この反射板９は例えば
ＳＵＳ３１６などの耐熱材料からなり、各電気ヒータか
らの放射エネルギーを反射させるための耐熱性を有する
クロム系材料による表面処理が施されており、各電気ヒ
ータから発する放射エネルギーを有効に反射する。ガラ
ス素材１は搬送アーム２によって加熱炉３内及び成形室
４内の下型６の成形面６ａ上に搬送可能となっており、
下型６上にガラス素材１が載置された状態で、加熱部材
５の加熱面５ａがガラス素材１の上面１ａに近接するこ
とによって、ほぼ均等厚の空隙７を形成することができ
る。The center of the heating member 5 has a diameter of 2 mm.
Vertically extending cylindrical inlet pipe 5 having a small inflow hole
d is provided. The introduction tube 5d is formed of quartz glass or the like, and an electric heater 5e is provided around the introduction tube 5d, and can be controlled to an arbitrary temperature by a temperature sensor and a temperature controller (not shown). This introduction pipe 5
d is supplied with nitrogen gas 8 at an arbitrary pressure and flow rate from a nitrogen gas supply device (not shown).
Glass material 1 and heating member 5 while being heated to a predetermined temperature
And can flow into the gap 7 between them. Reference numeral 9 denotes a reflector provided in the heating member 5 so as to be located on the back side of the electric heaters 5b and 5e. The reflection plate 9 is made of a heat-resistant material such as SUS316, and has been subjected to a surface treatment with a heat-resistant chromium-based material for reflecting the radiant energy from each electric heater. Reflects effectively. The glass material 1 can be transferred by the transfer arm 2 onto the forming surface 6a of the lower mold 6 in the heating furnace 3 and the forming chamber 4.
When the heating surface 5a of the heating member 5 is close to the upper surface 1a of the glass material 1 in a state where the glass material 1 is placed on the lower mold 6, the gap 7 having a substantially uniform thickness can be formed.
【００１３】ガラス素材１としては、例えば転移点４４
３℃，屈状点４７０℃，軟化点５６７℃の重フリントガ
ラスが使用され、その上面１ａおよび下面１ｂは研削・
研磨加工により非球面などのそれぞれ所望のレンズ形状
に近似した形状、例えば曲率半径Ｒ１００ｍｍの凹球面
及び曲率半径１５ｍｍの凹球面に加工されている。ま
た、中肉部分の厚さは例えば１．６ｍｍ、外径は例えば
２０ｍｍとなっている。このガラス素材１は進退自在な
搬送アーム２の載置穴２ａに載置される。As the glass material 1, for example, a transition point 44
Heavy flint glass having a temperature of 3 ° C., a bending point of 470 ° C., and a softening point of 567 ° C. is used.
It is formed into a shape approximating a desired lens shape such as an aspherical surface by polishing, for example, a concave spherical surface with a radius of curvature R of 100 mm and a concave spherical surface with a radius of curvature of 15 mm. The thickness of the inner wall portion is, for example, 1.6 mm, and the outer diameter is, for example, 20 mm. The glass material 1 is placed in a placement hole 2 a of a transfer arm 2 that can move forward and backward.
【００１４】図２は、上型１０，下型６を用いた成形工
程を示す。上型１０の材質及び加熱機構は下型６と同様
である。この上型１０の成形面１０ａは所望のレンズ面
に対応する形状に鏡面研磨されている。この上型１０は
加熱部材５を退避させた後、ガラス素材１の上面１ａに
接触させて加圧できるように図示しない機構により移動
可能となっている。１１は窒素ブロー装置であり、上型
１０の外周先端付近に位置し、中空のリング形状をした
ノズル部１１ａと、ノズル部１１ａに接続されて図示し
ない窒素ガス供給装置から常温の窒素ガスを導く導管部
１１ｂから成り、上型１０と連動して移動自在になって
いる。この場合、ノズル部１１ａの内周面には複数のノ
ズル１１ｃが開口されており、窒素ガスが流出自在にな
っている。FIG. 2 shows a molding process using the upper mold 10 and the lower mold 6. The material and the heating mechanism of the upper mold 10 are the same as those of the lower mold 6. The molding surface 10a of the upper mold 10 is mirror-polished into a shape corresponding to a desired lens surface. The upper mold 10 can be moved by a mechanism (not shown) so that the heating member 5 can be retracted and then brought into contact with the upper surface 1a of the glass material 1 and pressurized. Reference numeral 11 denotes a nitrogen blowing device, which is located near the outer peripheral end of the upper mold 10 and guides a normal temperature nitrogen gas from a hollow ring-shaped nozzle portion 11a and a nitrogen gas supply device (not shown) connected to the nozzle portion 11a. It is composed of a conduit portion 11b, and is movable in conjunction with the upper die 10. In this case, a plurality of nozzles 11c are opened on the inner peripheral surface of the nozzle portion 11a so that nitrogen gas can flow out.
【００１５】次に上記構造の成形装置により重フリント
ガラスからなり、厚肉部と薄肉部の肉厚比が２．８：
１，薄肉部の厚みが１．５ｍｍの両凹レンズを成形する
方法を示す。Next, the molding device having the above structure is made of heavy flint glass, and the thickness ratio of the thick portion to the thin portion is 2.8:
1 shows a method of forming a biconcave lens having a thin portion with a thickness of 1.5 mm.
【００１６】ガラス素材１は搬送アーム２上への載置状
態で加熱炉３内に搬送される。ガラス素材１の温度が成
形可能な温度、本実施例では６００℃となってから成形
室４内の下型６上に移送する。この温度は下型の温度や
加熱部材５の発熱量及び加熱部材５から空隙７へ流入さ
れた加熱気体によってガラス素材上面１ａに作用する圧
力及び上型、下型によってガラス素材１に作用する圧力
によって最適値を設定する。また、成形完了後に、所定
の形状を得るに十分なガラスの流動量が確保されるよう
に設定する。下型６上にガラス素材１を移送してから、
ただちに下型６を上昇して、成形面６ａをガラス素材１
の下面１ｂに接触させて停止すると同時に加熱部材５を
下降して、加熱面５ａとガラス素材１の上面１ａを近接
させ、空隙７を形成する。この時の下型６の温度はガラ
ス転移点温度以上が望ましく、本実施例では４５５℃が
良好である。ガラス転移点温度以下では下面１ｂ付近の
ガラスが急速に固化して成形作用が停止するためであ
る。加熱部材５の電気ヒータ５ｂは７００℃に設定され
ており、また窒素ガス８の温度が５６０℃となるように
電気ヒータ５ｅの加熱温度がコントロールされている。
空隙７が形成されると同時に窒素ガス８を流入させ、ガ
ラス素材１の上面１ａの粘度上昇を遅延させるように熱
を与えながら同時に１０秒間加圧して下面１ｂ付近の成
形をほぼ完了させる。この場合、電気ヒータ５ｂの温度
及び窒素ガス８の温度は、上面１ａの粘度上昇を遅延さ
せるように設定するが、上面１ａの温度以上であること
が望ましい。また、空隙７の間隔や窒素ガスの流量及び
圧力は、空隙７内の窒素ガスが十分にガラスの流動を生
じさせるように設定する。この場合、加熱部材５を微動
して空隙７の間隔を変化させて、上面１ａに作用する加
圧力を制御するようにしてもよい。このようにすること
により、下面１ｂを成形しつつも固化の速い薄肉部の粘
度上昇を遅延させることができる。The glass material 1 is transported into the heating furnace 3 while being placed on the transport arm 2. The glass material 1 is transferred onto the lower mold 6 in the molding chamber 4 after the temperature of the glass material 1 reaches a temperature at which molding is possible, in this embodiment, 600 ° C. This temperature is the temperature of the lower mold, the amount of heat generated by the heating member 5, the pressure acting on the glass material upper surface 1a by the heating gas flowing into the gap 7 from the heating member 5, and the pressure acting on the glass material 1 by the upper mold and the lower mold. To set the optimal value. In addition, it is set so that a flow amount of glass sufficient to obtain a predetermined shape is secured after the completion of molding. After transferring the glass material 1 onto the lower mold 6,
Immediately, the lower mold 6 is raised, and the molding surface 6a is
At the same time, the heating member 5 is lowered and brought into contact with the lower surface 1b of the glass material 1. The heating member 5 is lowered to bring the heating surface 5a and the upper surface 1a of the glass material 1 close to each other to form a void 7. At this time, the temperature of the lower mold 6 is desirably equal to or higher than the glass transition point temperature, and is preferably 455 ° C. in this embodiment. If the temperature is equal to or lower than the glass transition point temperature, the glass near the lower surface 1b is rapidly solidified and the forming operation is stopped. The electric heater 5b of the heating member 5 is set at 700 ° C., and the heating temperature of the electric heater 5e is controlled so that the temperature of the nitrogen gas 8 becomes 560 ° C.
At the same time when the void 7 is formed, the nitrogen gas 8 is flowed in, and while applying heat so as to delay the rise of the viscosity of the upper surface 1a of the glass material 1, the pressure is simultaneously applied for 10 seconds to substantially complete the molding near the lower surface 1b. In this case, the temperature of the electric heater 5b and the temperature of the nitrogen gas 8 are set so as to delay the increase in the viscosity of the upper surface 1a, but are desirably equal to or higher than the temperature of the upper surface 1a. Further, the interval between the voids 7 and the flow rate and pressure of the nitrogen gas are set such that the nitrogen gas in the voids 7 sufficiently generates the glass flow. In this case, the pressing force acting on the upper surface 1a may be controlled by slightly moving the heating member 5 to change the interval of the gap 7. By doing so, it is possible to delay the rise in viscosity of the thin portion that is rapidly solidified while molding the lower surface 1b.
【００１７】次に加熱部材５をガラス素材１の上面１ａ
より退避させてから、上型１０の成形面１０ａを上面１
ａに接触させて加圧しつつ、窒素ブロー装置１１から所
定量の窒素ガスをガラス及び上型、下型に吹きつけて、
ガラスの温度がガラス転移点温度以下になるように冷却
する。この時の上型１０の温度及び加圧力はガラス素材
１の上面１ａの温度によって設定するが、上型の温度は
良好な転写精度を得るための必要上からガラス転移点以
上が望ましく、本実施例では４５５℃とし、加圧力は十
分なガラスの流動を行うため、１００ｋｇｆ／ｃｍ2で
２０秒間保持する。このようにして押圧成形を行った後
上型１０、下型６を退避させてから、搬送アーム２を後
退させて成形品を取り出す。この成形品は両面同時に成
形した通常の成形方法で得た成形品に比べて、特に薄肉
部の粘度上昇を遅延させながら成形を進行させることが
できるので、ヒケがなく形状精度が良好である。Next, the heating member 5 is connected to the upper surface 1a of the glass material 1.
After retreating, the molding surface 10a of the upper mold 10 is
While contacting and pressurizing a, a predetermined amount of nitrogen gas is blown from the nitrogen blowing device 11 onto the glass and the upper and lower molds,
The glass is cooled so that the temperature of the glass becomes equal to or lower than the glass transition temperature. At this time, the temperature and pressure of the upper mold 10 are set by the temperature of the upper surface 1a of the glass material 1. The temperature of the upper mold is desirably equal to or higher than the glass transition point from the viewpoint of obtaining good transfer accuracy. In the example, the temperature is 455 ° C., and the pressure is maintained at 100 kgf / cm 2 for 20 seconds in order to sufficiently flow the glass. After performing the press molding in this way, the upper mold 10 and the lower mold 6 are retracted, and then the transfer arm 2 is retracted to take out the molded product. Compared with a molded product obtained by a usual molding method in which both surfaces are molded simultaneously, molding can be advanced while delaying a rise in viscosity of a thin portion in particular, so that there is no sink mark and the shape accuracy is good.
【００１８】従って、かかる方法では凸レンズ、両凹レ
ンズ以外の形状の光学素子や重フリントガラス以外の硝
材からなる光学素子も同様にして成形することができ
る。Therefore, in this method, an optical element having a shape other than a convex lens and a biconcave lens and an optical element made of a glass material other than heavy flint glass can be formed in the same manner.
【００１９】[0019]
【実施例２】図３は本発明の実施例２を示し、前記実施
例１と同一の要素は同一符号で対応させることにより重
複する説明を省略する。この実施例２においては加熱部
材５下端部の加熱面５ａが外周に向かうにつれて肉厚と
なっており、これにより電気ヒータ５ｂは外周に向かう
に従って、ガラス素材１から遠ざかっている。Second Embodiment FIG. 3 shows a second embodiment of the present invention, in which the same elements as those in the first embodiment are denoted by the same reference numerals, and a duplicate description will be omitted. In the second embodiment, the heating surface 5a at the lower end of the heating member 5 becomes thicker toward the outer periphery, whereby the electric heater 5b moves away from the glass material 1 toward the outer periphery.
【００２０】このような構成では加熱部材５がガラス素
材１の上面１ａに近接した場合のガラス素材１の中央側
の薄肉部が電気ヒータ５ｂに近接する位置関係となって
いる。これにより薄肉部近傍の上面程、粘度上昇を遅延
させるように作用する。従って、実施例１に比べてさら
に肉厚比の大きい形状の成形品に対しても良好な形状精
度で形成することができる。なお、この実施例２では加
熱部材５の加熱手段の発熱量をガラス素材１の薄肉部の
上面に近い程大きくしても良く、加熱された気体の温度
をガラス素材１の薄肉部の上面に近い程高くしても良
い。In such a configuration, when the heating member 5 approaches the upper surface 1a of the glass material 1, the thin portion on the center side of the glass material 1 has a positional relationship to approach the electric heater 5b. Thus, the upper surface near the thin portion acts to delay the rise in viscosity. Therefore, it is possible to form a molded product having a greater thickness ratio with good shape accuracy as compared with the first embodiment. In the second embodiment, the calorific value of the heating means of the heating member 5 may be increased closer to the upper surface of the thin portion of the glass material 1, and the temperature of the heated gas may be increased to the upper surface of the thin portion of the glass material 1. It may be higher as it is closer.
【００２１】[0021]
【実施例３】図４は本発明の実施例３を示し、実施例１
と同一の要素は同一の符号で対応させてある。この実施
例３では加熱部材１５が円筒状の加圧筒１５ｂと、加圧
筒１５ｂの下端部に固定された加熱体１５ａとにより構
成されている。加熱体１５ａは耐熱性の多孔質材からな
り、その下端の加熱面１５ｃはガラス素材１の上面１ａ
の形状を反転させた曲率半径（例えばＲ１００ｍｍ）の
凸球面に成形されている。また、加熱体１５ａの上端１
５ｄには電気ヒータ１５ｅが設置され、この電気ヒータ
１５ｅは図示しない温度センサ及び温度コントローラに
より、任意の温度に制御自在となっている。一方、加圧
筒１５ｂは、図示しない窒素ガス供給装置から任意の圧
力及び流量の窒素ガス１６が供給されるように構成され
ている。窒素ガス１６は多孔質材でできた加熱体１５ａ
の上端面１５ｄから内部に流入するとともに、電気ヒー
タ１５ｅからの熱を受けて所定の温度に加熱されなが
ら、下端の加熱面１５ｃより空隙７に流入できるように
なっている。このような構成では、加熱体１５ａから流
入する加熱された窒素ガスが加熱面１５ｃ全面から流出
するのでほぼ均等にガラス素材１の上面１ａに加圧力を
作用させることができる。このためガラス素材１の下面
１ｂの成形がすみやかに進行し、短時間で高精度の形状
とすることができる。FIG. 4 shows a third embodiment of the present invention.
The same elements as those described above are assigned the same reference numerals. In the third embodiment, the heating member 15 includes a cylindrical pressure cylinder 15b and a heating element 15a fixed to the lower end of the pressure cylinder 15b. The heating body 15a is made of a heat-resistant porous material, and the heating surface 15c at the lower end thereof is an upper surface 1a of the glass material 1.
Is formed into a convex spherical surface having a radius of curvature (for example, R100 mm) obtained by inverting the shape. Also, the upper end 1 of the heating body 15a
An electric heater 15e is provided in 5d, and the electric heater 15e can be freely controlled to an arbitrary temperature by a temperature sensor and a temperature controller (not shown). On the other hand, the pressurizing cylinder 15b is configured such that a nitrogen gas 16 at an arbitrary pressure and flow rate is supplied from a nitrogen gas supply device (not shown). The nitrogen gas 16 is a heating member 15a made of a porous material.
While flowing into the inside from the upper end surface 15d, and receiving heat from the electric heater 15e and being heated to a predetermined temperature, it can flow into the gap 7 from the lower heating surface 15c. In such a configuration, the heated nitrogen gas flowing from the heating body 15a flows out of the entire heating surface 15c, so that the pressing force can be applied to the upper surface 1a of the glass material 1 almost uniformly. For this reason, the molding of the lower surface 1b of the glass material 1 proceeds promptly, and a highly accurate shape can be obtained in a short time.
【００２２】[0022]
【発明の効果】以上、説明したように本発明は、薄肉部
のガラスの粘度上昇を遅延させつつ成形を行うことがで
きるので、肉厚比が２．５：１以上の偏肉の大きいレン
ズ形状、あるいは薄肉部が２ｍｍ以下のレンズ形状にお
いても形状精度の良好な成形品を成形することができ
る。As described above, according to the present invention, since the molding can be performed while delaying the increase in the viscosity of the thin-walled glass, a lens having a large thickness deviation of 2.5: 1 or more is used. A molded product having good shape accuracy can be formed even in a lens shape having a shape or a thin portion having a thickness of 2 mm or less.
【図１】本発明の実施例１における加熱気体供給工程を
示す断面図。FIG. 1 is a cross-sectional view showing a heating gas supply step in Embodiment 1 of the present invention.
【図２】本発明の実施例１における押圧成形工程を示す
断面図。FIG. 2 is a cross-sectional view illustrating a pressing step in the first embodiment of the present invention.
【図３】本発明の実施例２における加熱気体供給工程を
示す断面図。FIG. 3 is a cross-sectional view illustrating a heating gas supply step according to a second embodiment of the present invention.
【図４】本発明の実施例３における加熱気体供給工程を
示す断面図。FIG. 4 is a sectional view showing a heating gas supply step according to a third embodiment of the present invention.
１ ガラス素材 １ａ 上面 ５ 加熱部材 ６ 下型 ７ 空隙 DESCRIPTION OF SYMBOLS 1 Glass material 1a Upper surface 5 Heating member 6 Lower mold 7 Void
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C03B 11/00 C03B 23/00 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. 7 , DB name) C03B 11/00 C03B 23/00
Claims (2)
た一対の成形型で押圧成形した後、冷却する成形方法に
おいて、加熱軟化したガラス素材を前記成形型の下型に
載置する工程と、ガラス素材の上面形状を反転させた表
面形状を有する加熱部材を前記ガラス素材の上面に接近
させながらガラス素材と加熱部材との間の空隙に加熱気
体を供給する工程と、前記加熱部材を前記ガラス素材の
上面から退避させた後、ガラス素材の上面に成形型の上
型を接触させてガラス素材を押圧成形する工程とを備え
ていることを特徴とするガラス光学素子の成形方法。1. A method for cooling a glass material which has been heated and softened by pressing with a pair of molds having a molding surface, and then placing the heat-softened glass material on a lower mold of the mold. Supplying a heating gas to a gap between the glass material and the heating member while approaching a heating member having a surface shape obtained by inverting the upper surface shape of the glass material to the upper surface of the glass material; and A step of retracting the upper surface of the glass material and contacting the upper surface of the molding material with the upper surface of the glass material to press-mold the glass material.
を厚肉部よりも高温とする温度分布を有して加熱するこ
とを特徴とするガラス光学素子の成形方法。2. The method of molding a glass optical element, wherein the heating member heats the glass material with a temperature distribution such that a thin portion of the glass material has a higher temperature than a thick portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3204943A JP3068261B2 (en) | 1991-07-19 | 1991-07-19 | Glass optical element molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3204943A JP3068261B2 (en) | 1991-07-19 | 1991-07-19 | Glass optical element molding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0524858A JPH0524858A (en) | 1993-02-02 |
| JP3068261B2 true JP3068261B2 (en) | 2000-07-24 |
Family
ID=16498910
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3204943A Expired - Fee Related JP3068261B2 (en) | 1991-07-19 | 1991-07-19 | Glass optical element molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3068261B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001180946A (en) * | 1999-12-24 | 2001-07-03 | Minolta Co Ltd | Method for forming optical glass element and forming apparatus for optical glass with method |
| JP2008083190A (en) * | 2006-09-26 | 2008-04-10 | Olympus Corp | Method for molding optical element |
-
1991
- 1991-07-19 JP JP3204943A patent/JP3068261B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0524858A (en) | 1993-02-02 |
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