JP2718452B2 - Glass optical element molding method - Google Patents

Glass optical element molding method

Info

Publication number
JP2718452B2
JP2718452B2 JP1013348A JP1334889A JP2718452B2 JP 2718452 B2 JP2718452 B2 JP 2718452B2 JP 1013348 A JP1013348 A JP 1013348A JP 1334889 A JP1334889 A JP 1334889A JP 2718452 B2 JP2718452 B2 JP 2718452B2
Authority
JP
Japan
Prior art keywords
molding
optical element
glass
mold
temperature
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
Application number
JP1013348A
Other languages
Japanese (ja)
Other versions
JPH02196039A (en
Inventor
光夫 後藤
弘 伊藤
暢喜 岩崎
英司 川村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Olympus Corp
Original Assignee
Olympus Optic Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Olympus Optic Co Ltd filed Critical Olympus Optic Co Ltd
Priority to JP1013348A priority Critical patent/JP2718452B2/en
Publication of JPH02196039A publication Critical patent/JPH02196039A/en
Application granted granted Critical
Publication of JP2718452B2 publication Critical patent/JP2718452B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B11/00Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
    • C03B11/12Cooling, heating, or insulating the plunger, the mould, or the glass-pressing machine; cooling or heating of the glass in the mould

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、ガラス光学素子の成形素材を加熱軟化した
後、成形用金型にて押圧することにより、研削、研磨加
工等を必要とせず、高い面精度と面粗度とを有するガラ
ス光学素子を成形できるガラス光学素子の成形方法に関
する。
DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention does not require grinding, polishing, and the like by heating and softening a molding material of a glass optical element and then pressing it with a molding die. The present invention relates to a method for forming a glass optical element capable of forming a glass optical element having high surface accuracy and surface roughness.

〔従来の技術〕[Conventional technology]

従来、レンズ、プリズム、フィルター等の光学素子の
多くは、ガラス素材の研削、研磨処理を主とした方法に
よって形成されてきた。しかしながら、かかる処理には
相当な時間および熟練技術が必要とされ、特に、非球面
レンズを研磨等処理によって形成するには、一層高度な
研磨等技術が要求され、かつ処理時間が長くなり、短時
間に大量のガラス光学素子を製造することは困難であっ
た。そこで例えば特開昭61−132525号公報に開示される
ように、一対の成形用金型間にガラス素材を加熱軟化し
て移送配置し、これを成形用金型により押圧成形するだ
けでレンズ等のガラス光学素子を成形する方法が開発実
施され注目されている。
2. Description of the Related Art Conventionally, many optical elements such as lenses, prisms, and filters have been formed mainly by grinding and polishing a glass material. However, such processing requires a considerable amount of time and skill, and in particular, in order to form an aspherical lens by polishing or the like, more advanced polishing or the like is required, and the processing time becomes longer and shorter. It has been difficult to produce large quantities of glass optical elements in time. Therefore, as disclosed in, for example, JP-A-61-132525, a glass material is heated and softened between a pair of molding dies, transferred and disposed, and this is simply pressed by a molding die to form a lens or the like. A method for molding a glass optical element has been developed and implemented, and has attracted attention.

第5図は、上記成形方法に使用する装置を示すもの
で、対をなして同軸的に対向配置された上型1と下型2
とからなる成形用金型が設けられている。上型1および
下型2の各対向面には、所望のレンズ形状に対応した形
状の成形面1a,2aが形成されている。そして、上型1と
下型2とは、図示を省略した駆動装置に連結されてお
り、相互に接近離反自在となっている。また、上型1と
下型2は、各外周面に離型部材3,4が摺動自在に嵌合さ
れるとともに、ガイド部材5,6により支持されている。
FIG. 5 shows an apparatus used in the above-mentioned molding method, in which an upper die 1 and a lower die 2 which are coaxially opposed to each other in a pair.
Is provided. Molding surfaces 1a and 2a having a shape corresponding to a desired lens shape are formed on the opposing surfaces of the upper mold 1 and the lower mold 2, respectively. The upper mold 1 and the lower mold 2 are connected to a drive device (not shown), and are allowed to approach and move away from each other. The upper mold 1 and the lower mold 2 have release members 3 and 4 slidably fitted to respective outer peripheral surfaces thereof and are supported by guide members 5 and 6.

上型1と下型2間には、ガラス素材7を載置する載置
台8を支持する支持台9が配置されている。この支持台
9の両側には、ガラス素材7を加熱軟化するための加熱
炉10と押圧成形されたガラス光学素子と徐冷するための
徐冷炉11が配置されている。さらに、ガラス素材7を載
置した載置台8を挟持して加熱炉10および支持台9に搬
送し、かつ押圧成形後のガラス光学素子を支持台9から
徐冷炉に搬送するための一対の搬送部材12,13が設けら
れている。
Between the upper mold 1 and the lower mold 2, a support table 9 for supporting a mounting table 8 on which the glass material 7 is mounted is arranged. On both sides of the support 9, a heating furnace 10 for heating and softening the glass material 7, a press-molded glass optical element, and a slow cooling furnace 11 for slow cooling are arranged. Further, a pair of transfer members for holding the mounting table 8 on which the glass material 7 is mounted and transporting the glass optical element to the heating furnace 10 and the support table 9 and transporting the glass optical element after press molding from the support table 9 to the annealing furnace. 12,13 are provided.

上記構成の成形装置によりガラス光学素子を成形する
方法を説明すると、まず、円柱状に切断したガラス素材
7を載置台8に載置し、この載置台8を一対の搬送部材
12,13で挟持しつつ加熱炉10内に搬送する。そしてガラ
ス素材を貫入法による粘度−温度曲線により求めた変曲
点付近の温度(ガラス素材の粘度が略106〜108ポアズと
なる温度)に加熱軟化した後、搬送部材12,13を介して
載置台8を支持台9上に搬送してガラス素材7を上型1
と下型2間に配置し、ガラス素材7の転移点付近の温度
に加熱保持した上下両型1,2により押圧成形する。次
に、押圧成形が完了すると、上型1の離型部材3は下降
して押圧成形後のガラス光学素子の外周部を下方に押圧
し、上型1は上昇してガラス光学素子を成形面1aから離
反するとともに、下型2の離型部材4は上昇してガラス
光学素子の外周部を上方に押圧し、下型2は下降してガ
ラス光学素子を成形面2aから離反する。離型後、ガラス
光学素子は、載置台8に載置され、搬送部材12,13を介
して徐冷炉11内に搬送してガラス光学素子を徐冷して最
終製品を得るものである。
A method of molding a glass optical element by the molding apparatus having the above configuration will be described. First, a glass material 7 cut into a column shape is placed on a mounting table 8, and the mounting table 8 is mounted on a pair of transport members.
The material is conveyed into the heating furnace 10 while being sandwiched between 12 and 13. Then, the glass material is heated and softened to a temperature near the inflection point (a temperature at which the viscosity of the glass material becomes approximately 10 6 to 10 8 poise) determined by a viscosity-temperature curve obtained by the intrusion method, and then, is conveyed through the transfer members 12 and 13. The glass table 7 is transferred to the support table 9 by the
The lower and upper dies 1 and 2 are pressed between the upper and lower dies 1 and 2 which are placed between the upper and lower dies 2 and heated and maintained at a temperature near the transition point of the glass material 7. Next, when the press molding is completed, the release member 3 of the upper mold 1 descends to press the outer peripheral portion of the glass optical element after the press molding downward, and the upper mold 1 ascends to put the glass optical element on the molding surface. At the same time, the release member 4 of the lower mold 2 rises and presses the outer peripheral portion of the glass optical element upward, and the lower mold 2 descends and separates the glass optical element from the molding surface 2a. After the mold release, the glass optical element is mounted on the mounting table 8 and conveyed into the annealing furnace 11 via the conveying members 12 and 13 to gradually cool the glass optical element to obtain a final product.

〔発明が解決しようとする課題〕[Problems to be solved by the invention]

上記従来の成形方法においては次のような問題点があ
った。
The conventional molding method has the following problems.

まず、成形面1a,2aとガラス光学素子の界面にオプテ
ィカルコンタクトにより密着力が発生し易く、離型時に
強い離型力を必要とするため、離型部材3,4に押圧され
るガラス光学素子の外周部にカケが生じ、不良品となる
問題点があった。さらに、ガラスのカケが成形面1a,2a
に付着し、その後に押圧成形されるガラス光学素子が外
観不良となり、また、金型寿命が短命化するという問題
点があった。
First, the optical contact is easily generated by the optical contact at the interface between the molding surfaces 1a, 2a and the glass optical element, and a strong release force is required at the time of release, so the glass optical element pressed by the release members 3, 4 There was a problem that chips were generated on the outer peripheral portion of the above, and it became a defective product. In addition, the chips of the glass are
There is a problem that the glass optical element that is adhered to the substrate and then pressed and formed has a poor appearance and the life of the mold is shortened.

さらに、強い離型力により離型した際、ガラス光学素
子の形状精度が低下する問題点があった。例えば、カメ
ラ用レンズにあっては、曲率の精度が±1μm以内、形
状の非対称性を示すアスおよび曲率の部分的変化を示す
クセが±0.1μm以内の形状精度が必要とされるが、離
型力が大きいと離型時の変形により、形状精度が大きく
低下し、所望形状のレンズを得られないという問題点が
あった。
Further, there is a problem that the shape precision of the glass optical element is reduced when the mold is released by a strong releasing force. For example, in the case of a camera lens, the accuracy of the curvature is required to be within ± 1 μm, and the shape indicating the asymmetry of the shape and the characteristic indicating the partial change of the curvature are required to be within ± 0.1 μm. If the molding force is large, there is a problem that the deformation at the time of release causes a significant reduction in shape accuracy, and a lens having a desired shape cannot be obtained.

また、強い離型力に対応するために、高剛性の離型部
材を必要とするため、成形装置が複雑化するとともに大
型化する問題点があった。
Further, since a high-rigidity release member is required to cope with a strong release force, there has been a problem that the molding apparatus is complicated and the size is increased.

本発明は、上記従来の問題点に鑑みてなされたもので
あって、離型性を向上させてガラス光学素子の不良品発
生率を低減するとともに、成形用金型の寿命を延命化さ
せ、かつ形状精度の安定した高精度なガラス光学素子を
大量、安価に製造し得る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 view of the above-described conventional problems, and improves the releasability to reduce the defective product incidence rate of the glass optical element and extend the life of the molding die. It is another object of the present invention to provide a method for molding a glass optical element capable of producing a large amount of a high-precision glass optical element with stable shape accuracy at low cost.

〔課題を解決するための手段〕[Means for solving the problem]

上記目的を達成するために、本発明のガラス素子の成
形方法は、成形するガラス素材の転移点温度付近に加熱
した上下一対からなる成形用金型によって、この成形用
金型よりも高い温度に加熱軟化したガラス素材を押圧成
形するガラス光学素子の成形方法において、上記成形用
金型よりも高い温度に加熱軟化したガラス素材における
上型近傍と下型近傍とを同一冷却速度で押圧成形する第
1成形工程と、上記ガラス素材における上型近傍と下型
近傍とを冷却速度を変化させつつ押圧成形する第2成形
工程と、を有している。
In order to achieve the above object, the method for forming a glass element of the present invention is performed by using a pair of upper and lower molding dies heated near the transition temperature of the glass material to be molded, to a temperature higher than the molding die. In a method of molding a glass optical element by press-molding a heat-softened glass material, a method of press-molding the vicinity of an upper mold and a lower mold of a glass material heated and softened to a temperature higher than the molding die at the same cooling rate. The method includes a first forming step and a second forming step of press-forming the vicinity of the upper mold and the lower mold of the glass material while changing the cooling rate.

ここに、第1成形工程においては、上型と下型の温度
差は5℃以下、好ましくは1℃以下に制御する必要があ
る。上下両型間に5℃以上の温度差がある場合、加熱軟
化したガラス素材が成形用金型に接触した瞬間、低温の
金型に接したガラス素材表面が急激に冷却固化されて収
縮するため、ガラス素材表面と金型成形面に充分な圧力
が加えられないので成形面形状が正確に転写せず、ガラ
ス光学素子の形状精度が低下するためである。
Here, in the first molding step, it is necessary to control the temperature difference between the upper mold and the lower mold to 5 ° C. or less, preferably 1 ° C. or less. When there is a temperature difference of 5 ° C or more between the upper and lower molds, the surface of the glass material in contact with the low-temperature mold is rapidly cooled and solidified and shrinks as soon as the heat-softened glass material comes into contact with the molding die. In addition, since sufficient pressure is not applied to the surface of the glass material and the molding surface of the mold, the molding surface shape is not accurately transferred, and the shape accuracy of the glass optical element is reduced.

〔作 用〕(Operation)

本発明のガラス光学素子の成形方法においては、加熱
軟化したガラス素材を第1成形工程、第2成形工程と連
続する2つの工程で押圧成形している。
In the method for molding a glass optical element according to the present invention, the glass material that has been heated and softened is subjected to pressure molding in two steps that are continuous with the first molding step and the second molding step.

第1成形工程においては、上型と下型を同一温度に制
御し、加熱軟化状態のガラス素材は所望の光学素子に対
応した形状の金型成形面に高精度に転写させられるとと
もに、ガラス素材の温度は、押圧成形開始とともに急激
に低下を始め、わずか数秒で成形用金型温度まで冷却さ
れる。
In the first molding step, the upper mold and the lower mold are controlled to the same temperature, and the glass material in the heat-softened state is transferred with high precision to a mold molding surface having a shape corresponding to a desired optical element. Starts sharply with the start of press molding, and is cooled to the temperature of the molding die in just a few seconds.

第2成形工程においては、ガラス素材の冷却速度を部
分的に変化させつつ押圧成形させるもので、ガラス素材
における上型近傍と下型近傍で冷却速度を変化あるいは
押圧成形終了直前で温度に差を設けて温度低下量を変化
させるため、ガラス内部に収縮量の違いにより生ずる
「そり」に対応した弾性変形が発生する。即ち、ガラス
は冷却とともに収縮し、この冷却速度と収縮量との関係
において、冷却速度が速いほど実質的に変形しない温
度、即ちガラスの歪点(1014ポアズ)付近の温度に至る
までの収縮が小さくなるとともに、冷却する過程での温
度低下量が小さいほど収縮量が小さくなる特徴があるか
らである。かかる上記弾性変形は上下型を開いた時、押
圧成形後のガラス光学部品を離型させるように作用し、
離型力を低減させる。
In the second molding step, the glass material is press-formed while partially changing the cooling rate. The cooling rate is changed between the vicinity of the upper mold and the lower mold of the glass material, or the difference in the temperature is obtained immediately before the completion of the press molding. Since it is provided to change the amount of temperature decrease, elastic deformation corresponding to “warpage” caused by a difference in the amount of shrinkage occurs inside the glass. That is, the glass shrinks with cooling, and in the relationship between the cooling rate and the amount of shrinkage, as the cooling rate increases, the glass does not substantially deform, that is, shrinks to a temperature near the glass strain point (10 14 poise). Is smaller, and the smaller the amount of temperature decrease in the cooling process, the smaller the amount of shrinkage. Such elastic deformation, when opening the upper and lower molds, acts to release the glass optical component after press molding,
Reduce release force.

〔実 施 例〕〔Example〕

以下、図面を用いて、本発明の実施例を詳細に説明す
る。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(第1実施例) 第1図は、本発明に係るガラス光学素子の成形方法の
第1実施例の実施に使用する成形装置を示すもので、対
をなして同軸的に対向配置された上型21と下型22とから
なる成形用金型が構成されている。上型21および下型22
の各対向面には、所望の光学素子形状に対応した形状の
成形面21a,22aが形成されている。
First Embodiment FIG. 1 shows a molding apparatus used for carrying out a first embodiment of a method for molding a glass optical element according to the present invention. A molding die including the mold 21 and the lower mold 22 is configured. Upper mold 21 and Lower mold 22
Molding surfaces 21a and 22a having a shape corresponding to a desired optical element shape are formed on each of the opposed surfaces.

上型21は中央部に熱電対23が組み込まれるとともに、
外周部にヒータ24が取付けられている。熱電対23とヒー
タ24は、任意の熱履歴に設定自在な温度コントローラ25
に接続され、上型21の温度制御が熱電対23とヒータ24を
用いて行われるように構成されている。
The upper mold 21 incorporates a thermocouple 23 in the center,
A heater 24 is mounted on the outer periphery. Thermocouple 23 and heater 24 are temperature controller 25 that can be set to any heat history.
And the temperature of the upper mold 21 is controlled using a thermocouple 23 and a heater 24.

下型22は、型駆動軸26を介して型駆動装置27に連結さ
れて上下動自在に保持されており、上型21に対して接近
離反自在となっている。型駆動装置27は、任意の圧力プ
ロセスに設定自在な圧力コントローラ28に接続されてい
る。型駆動軸26と型駆動装置27間には、上記圧力コント
ローラ28に接続したロードセル29が設けられ、ガラス光
学素子の押圧成形時の押圧力制御が行われるように構成
されている。また、下型22は、上型21と同様に、中央部
に熱電対30が埋設され、外周部にヒータ31が取付けられ
ている。熱電対30とヒータ31は、任意な熱履歴に設定自
在な温度コントローラ32に接続され、下型21の温度制御
が熱電対30とヒータ31により行われるようになってい
る。そして、温度コントローラ25,32および圧力コント
ローラ28は、1個のシーケンサー33に接続され、シーケ
ンサー33により連動して作動されるようになっている。
その他の構成は、上記従来の成形装置と同様であるの
で、同一部分には同一番号を付して、その説明を省略す
る。
The lower mold 22 is connected to a mold drive device 27 via a mold drive shaft 26 and is held so as to be vertically movable, and is capable of approaching and separating from the upper mold 21. The mold driving device 27 is connected to a pressure controller 28 that can be set to any pressure process. A load cell 29 connected to the pressure controller 28 is provided between the mold drive shaft 26 and the mold drive device 27, and is configured to control the pressing force at the time of press forming the glass optical element. The lower mold 22 has a thermocouple 30 buried in the center and a heater 31 mounted on the outer periphery, like the upper mold 21. The thermocouple 30 and the heater 31 are connected to a temperature controller 32 which can be set to an arbitrary heat history, and the temperature of the lower mold 21 is controlled by the thermocouple 30 and the heater 31. The temperature controllers 25 and 32 and the pressure controller 28 are connected to one sequencer 33 and are operated by the sequencer 33 in conjunction with each other.
Other configurations are the same as those of the conventional molding apparatus described above, and therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted.

次に、上記構成の成形装置を用いて、本実施例のガラ
ス光学素子の成形方法を説明する。本実施例にあって
は、クラウンガラスの中で、通称SK11と呼ばれるガラス
転移点Tg:535℃、軟化点Sp:639℃、屈伏点At:559℃の光
学ガラス素材を用いて、外径20mm、肉厚3mmのカメラ用
非球面レンズを押圧成形した。
Next, a method for forming the glass optical element of the present embodiment using the forming apparatus having the above configuration will be described. In the present embodiment, in the crown glass, using an optical glass material having a glass transition point Tg: 535 ° C., a softening point Sp: 639 ° C., and a sag point At: 559 ° C. Then, an aspherical lens for a camera having a thickness of 3 mm was pressed and formed.

まず、ガラス素材7を所望の光学素子形状に近似する
球面に予め表面を研磨処理にて予備加工する。次に、こ
のガラス素材7を載置台8に載置するとともに、一対の
搬送部材12,13で載置台8を挟持して加熱炉10内に搬送
する。そして、ガラス素材7をガラス素材7の粘度が約
106〜108ポアズとなる温度である640℃に加熱軟化した
後、搬送部材12,13を介して上型21と下型22間に搬送し
て支持台9上に支持させるとともに、型駆動装置27を作
動して下型22を上昇させる。そして、上型21と下型22の
温度をガラス素材7のガラス転移温度付近である530℃
に設定し、200kg/cm2の押圧力でガラス素材7を5秒間
押圧成形しつつ上下両型21,22の型温まで冷却する(第
1成形工程)。次に第1成形工程に連続して、下型22の
型温のみを500℃に達するまで徐々に下降し、ガラス素
材7の下型22近傍温度を徐々に冷却しつつ200kg/cm2
押圧力で10秒間押圧成形する(第2成形工程)。その
後、上型21,下型22を開いて、押圧成形を完了し、成形
されたガラス光学素子(図示省略)を載置台8に載置す
る。そして、搬送部材12,13を介して載置台8とともに
ガラス光学素子を徐冷炉11内に搬送し、徐冷後の最終製
品としてのガラス光学素子を取り出す。
First, the surface of the glass material 7 is preliminarily processed by a polishing process in advance into a spherical surface approximating a desired optical element shape. Next, the glass material 7 is placed on the mounting table 8, and the glass table 7 is conveyed into the heating furnace 10 while the mounting table 8 is sandwiched between the pair of conveying members 12 and 13. Then, the viscosity of the glass material 7 is reduced to about
After softening by heating to 640 ° C., which is a temperature of 10 6 to 10 8 poise, the material is transferred between the upper die 21 and the lower die 22 via the transfer members 12 and 13 to be supported on the support 9 and to be driven. The lower die 22 is raised by operating the device 27. Then, the temperatures of the upper mold 21 and the lower mold 22 are set to 530 ° C., which is near the glass transition temperature of the glass material 7.
The glass material 7 is cooled to the mold temperature of the upper and lower molds 21 and 22 while the glass material 7 is molded by pressing with a pressing force of 200 kg / cm 2 for 5 seconds (first molding step). Next, following the first molding step, only the mold temperature of the lower mold 22 is gradually lowered until it reaches 500 ° C., and while the temperature near the lower mold 22 of the glass material 7 is gradually cooled, a pressing of 200 kg / cm 2 is performed. Press molding with pressure for 10 seconds (second molding step). After that, the upper mold 21 and the lower mold 22 are opened to complete the press molding, and the molded glass optical element (not shown) is mounted on the mounting table 8. Then, the glass optical element is transported together with the mounting table 8 into the annealing furnace 11 via the transport members 12 and 13, and the glass optical element as the final product after the annealing is taken out.

次に、上記成形方法の作用を第2図を用いて説明す
る。
Next, the operation of the molding method will be described with reference to FIG.

第2図は、上型21,下型22およびガラス素材7の上型
近傍温度と下型近傍温度の熱履歴の経時的変化を示すグ
ラフ図である。
FIG. 2 is a graph showing a change over time in the thermal history of the upper mold 21, the lower mold 22, and the glass material 7 near the upper mold and the lower mold.

まず、第1成形工程において、640℃に加熱軟化され
たガラス素材7は、上型21と下型22による押圧成形開始
と同時に急激に冷却され、上下両型21,22の型温530℃と
ほぼ同温度となる。この時、ガラス素材7は、所望の光
学素子に対応した上下両型21,22の成形面21a,22a形状に
高精度に転写される。
First, in the first molding step, the glass material 7 heated and softened to 640 ° C. is rapidly cooled at the same time as the press molding by the upper mold 21 and the lower mold 22 is started, and the mold temperature of the upper and lower molds 21 and 22 is 530 ° C. It is almost the same temperature. At this time, the glass material 7 is transferred with high accuracy to the shapes of the molding surfaces 21a and 22a of the upper and lower molds 21 and 22 corresponding to a desired optical element.

次に、第2成形工程において、下型22のみが530℃か
ら500℃に連続して下降され、第2成形工程終了時、即
ち離型時に、ガラス素材7は、その上型近傍と下型近傍
との間に約30℃の温度差を有するように徐々に冷却され
る。この時、ガラス素材内部での冷却速度の違いと離型
時の温度差による収縮量の差にって、ガラス光学素子内
部に生じる「そり」に対応した弾性変形が発生し、上下
両型21,22とガラス光学素子の密着力が低下する。
Next, in the second molding step, only the lower mold 22 is continuously lowered from 530 ° C. to 500 ° C., and at the end of the second molding step, that is, at the time of mold release, the glass material 7 is moved near the upper mold and the lower mold. It is gradually cooled so as to have a temperature difference of about 30 ° C. with the vicinity. At this time, due to the difference in the cooling rate inside the glass material and the difference in the amount of shrinkage due to the temperature difference at the time of mold release, elastic deformation corresponding to the “warp” generated inside the glass optical element occurs, and the upper and lower molds 21 , 22 and the glass optical element are reduced in adhesion.

本実施例によれば、下型22のみ型温を低下させる簡単
な手段により、離型時の成形用金型とガラス光学素子と
の界面で生ずる密着力を低減でき、離型部材等の手段を
用いることなくガラス光学素子を離型できる。さらに、
短時間で下型22を所定の温度に昇温可能で連続して次の
ガラス素材7を押圧成形でき、大量のガラス光学素子を
短時間で製造することができる。
According to the present embodiment, the adhesion force generated at the interface between the molding die and the glass optical element at the time of release can be reduced by a simple means for lowering the mold temperature only in the lower mold 22. The glass optical element can be released without using the glass. further,
The temperature of the lower mold 22 can be raised to a predetermined temperature in a short time, the next glass material 7 can be continuously pressed and molded, and a large number of glass optical elements can be manufactured in a short time.

(第2実施例) 本実施例のガラス光学素子の成形方法の特徴は、第2
成形工程において上型と下型の双方の型温を温度勾配を
異ならしめて低下して押圧成形する点である。なお、本
実施例の実施に使用する成形装置は、第1図の成形装置
と同様に構成してあるので説明と図示を省略するととも
に、本実施例を同一番号を用いて説明する。
(Second Embodiment) The feature of the method for forming a glass optical element of this embodiment is as follows.
The point is that in the molding step, the mold temperature of both the upper mold and the lower mold is lowered by making the temperature gradient different, and press molding is performed. The molding apparatus used in the embodiment is configured in the same manner as the molding apparatus shown in FIG. 1, so that the description and illustration are omitted, and the embodiment is described using the same reference numerals.

以下に、本実施例のガラス光学素子の成形方法を第3
図を用いて説明する。
Hereinafter, the molding method of the glass optical element of the present embodiment will be described as a third method.
This will be described with reference to the drawings.

第3図は、上型21,下型22およびガラス素材7の上型
近傍温度、下型近傍温度の熱履歴の経時的変化と成形圧
力を示すグラフ図である。
FIG. 3 is a graph showing the change over time in the heat history of the upper mold 21, the lower mold 22 and the temperature near the upper mold and the temperature near the lower mold of the glass material 7 and the molding pressure.

まず、上記第1実施例と同一の手順で第1成形工程ま
で実施する。即ち、予め研磨処理したガラス素材7を加
熱炉10内で粘度が106〜108ポアズとなる温度の640℃に
加熱軟化後、530℃に設定保持した上下両型21、22によ
り200kg/cm2の押圧力で5秒間押圧成形しガラス素材7
を冷却する。
First, the same procedure as in the first embodiment is performed up to the first molding step. That is, the glass material 7 which has been polished in advance is heated and softened in a heating furnace 10 to 640 ° C. at a temperature at which the viscosity becomes 10 6 to 10 8 poise, and then the upper and lower molds 21 and 22 which are set at 530 ° C. and 200 kg / cm. Press molding for 5 seconds with a pressing force of 2
To cool.

次に、上記第1成形工程に連続して、上型21を520℃
および下型22を500℃に達するまで徐々に冷却するとと
もに、成形押圧力を100kg/cm2に減圧して10秒間押圧成
形する。その後、上型21,下型22を開き成形を完了す
る。そして、上記第1実施例と同様に徐冷炉11内の搬送
して徐冷した後、最終製品としてのガラス光学素子を取
り出す。
Next, the upper mold 21 is kept at 520 ° C.
The lower mold 22 is gradually cooled until the temperature reaches 500 ° C., and the molding pressing force is reduced to 100 kg / cm 2 to perform press molding for 10 seconds. Thereafter, the upper mold 21 and the lower mold 22 are opened to complete the molding. Then, similarly to the first embodiment, the glass optical element as a final product is taken out after being conveyed in the annealing furnace 11 and gradually cooled.

本実施例にあっては、第2成形工程において上型21と
下型22とを冷却する温度勾配に差を設けてガラス素材7
を徐冷することにより、上記第1実施例と同様にガラス
光学素子内部に生ずる「そり」に対応した弾性変形が発
生する。
In the present embodiment, a difference is set in the temperature gradient for cooling the upper mold 21 and the lower mold 22 in the second molding step so that the glass material 7 is cooled.
Is gradually cooled, an elastic deformation corresponding to the "warp" generated inside the glass optical element occurs as in the first embodiment.

本実施例によれば、上記第1実施例と同様に、ガラス
光学素子の離型時の成形用金型とガラス光学素子との界
面に生ずる密着力が低減され、離型部材等の手段を用い
ることなくガラス光学素子を離型できる。
According to the present embodiment, similarly to the first embodiment, the adhesion force generated at the interface between the molding die and the glass optical element at the time of releasing the glass optical element is reduced. The glass optical element can be released without using it.

さらに、第2成形工程における成形押圧力を第1成形
工程より減圧するという簡単な手段で、より形状精度
(転写精度)が向上し、高品質なガラス光学素子を成形
できる。
Further, the shape accuracy (transfer accuracy) is further improved by a simple means of reducing the molding pressing force in the second molding process from that in the first molding process, and a high quality glass optical element can be molded.

なお、本実施例では、第2成形工程において、上型21
と下型22を同時に冷却しつつ押圧成形した例を説明した
が、上型21と下型22を冷却する時間のタイミングを変化
させて実施することができる。さらに、下型22の冷却手
段は、温度コントローラ32を用いる手段に限定されず、
下型22に冷却ガス(例えば窒素ガス等)等を吹き付ける
手段にて下型22を冷却しつつ実施することができる。
In this embodiment, in the second molding step, the upper mold 21
Although the example in which the pressure molding is performed while simultaneously cooling the upper mold 21 and the lower mold 22 has been described, the present invention can be implemented by changing the timing of the time for cooling the upper mold 21 and the lower mold 22. Further, the cooling means of the lower mold 22 is not limited to the means using the temperature controller 32,
It can be carried out while cooling the lower mold 22 by means of blowing a cooling gas (for example, nitrogen gas or the like) or the like onto the lower mold 22.

(第3実施例) 本実施例の光学素子の成形方法の特徴は、第1成形工
程と第2工程における上下両型の型温を変化させること
なく、ガラス素材を載置する載置台を温度変化させて第
2成形工程におけるガラス素材の温度を変化させる点で
ある。
(Third Embodiment) The characteristic of the optical element molding method of the present embodiment is that the temperature of the mounting table on which the glass material is placed is maintained without changing the mold temperatures of the upper and lower molds in the first molding step and the second step. The point is that the temperature of the glass material in the second forming step is changed.

第4図は、上記成形方法の実施に使用する成形装置の
要部を示す断面図である。
FIG. 4 is a sectional view showing a main part of a molding apparatus used for carrying out the molding method.

図において40で示すのは、載置台8の温度を制御する
ための温調部材で、図示を省略した駆動装置により支持
台9上方で上下自在に配置されている。温調部材40は、
搬送部材12,13を介して支持台9上に支持された載置台
8の外形部を囲繞し得るように構成されている。温調部
材40には、ヒータと冷却管からなる温調材41と熱電対42
とが組まれている。温調材41および熱電対42は、温度コ
ントローラ43に接続され、温調部材40の温度制御を行う
ことができるようになっている。なお、上記成形装置に
あっては、第5図に示した成形装置とほぼ同様な構成で
実施できるので、同一部分には同一番号を付してある。
In the figure, reference numeral 40 denotes a temperature control member for controlling the temperature of the mounting table 8, which is arranged vertically above the support table 9 by a driving device (not shown). The temperature control member 40 is
It is configured to surround the outer shape of the mounting table 8 supported on the support table 9 via the transfer members 12 and 13. The temperature control member 40 includes a temperature control material 41 composed of a heater and a cooling pipe and a thermocouple 42.
Has been formed. The temperature control member 41 and the thermocouple 42 are connected to a temperature controller 43 so that the temperature of the temperature control member 40 can be controlled. In the above-mentioned molding apparatus, since it can be implemented by a configuration substantially similar to that of the molding apparatus shown in FIG. 5, the same parts are denoted by the same reference numerals.

次に、上記構成の成形装置を用いて、本実施例のガラ
ス光学素子の成形方法を説明する。本実施例にあって
は、ガラス素材として通称SF8と呼ばれるガラス転移点T
g:443℃、軟化点Sp:567℃、屈伏点At:470℃のフリント
ガラスを用いて、外径7mm、肉厚5mmの光ディスクピック
アップ用非球面対物レンズを押圧成形した。
Next, a method for forming the glass optical element of the present embodiment using the forming apparatus having the above configuration will be described. In the present embodiment, a glass transition point T commonly called SF8 as a glass material
An aspheric objective lens for an optical disk pickup having an outer diameter of 7 mm and a thickness of 5 mm was press-formed using flint glass having a g of 443 ° C., a softening point Sp: 567 ° C., and a sag point At: 470 ° C.

まず、ガラス素材7を載置台8に載置するとともに、
搬送部材12,13で載置台8を挟持して加熱炉10内に搬送
する。そして、ガラス素材7を550℃に加熱軟化した
後、搬送部材12,13を介して支持台9上に載置台8を搬
送し、ガラス素材7を400℃に設定された上下両型1,2に
より押圧成形する。この押圧成形における第1成形工程
として、まず、ガラス素材7を100kg/cm2の押圧力で5
秒間押圧成形する。次に、第2成形工程として、温調部
材41により載置台8を介して下型2に近接しているガラ
ス素材7下部の温度を390℃に達するまで徐々に冷却す
るとともに、ガラス素材7の上部温度を400℃に保持し
つつ、80kg/cm2の押圧力で10秒間押圧成形する。その
後、上型1,下型2を開いて押圧成形を完了し、成形され
たガラス光学素子(図示省略)を載置台8とともに搬送
部材12,13を介して徐冷炉11内に搬送し、徐冷後の最終
製品としてのガラス光学素子を取り出す。
First, while placing the glass material 7 on the mounting table 8,
The mounting table 8 is held between the transfer members 12 and 13 and transferred into the heating furnace 10. Then, after the glass material 7 is heated and softened to 550 ° C., the mounting table 8 is transferred onto the support table 9 via the transfer members 12 and 13, and the upper and lower molds 1 and 2 set at 400 ° C. Press molding. As a first forming step in this press forming, first, a glass material 7 is pressed at a pressing force of 100 kg / cm 2 for 5 minutes.
Press molding for seconds. Next, as a second molding step, the temperature of the lower part of the glass material 7 adjacent to the lower mold 2 via the mounting table 8 is gradually cooled by the temperature control member 41 until the temperature reaches 390 ° C. While maintaining the upper temperature at 400 ° C., press molding is performed for 10 seconds with a pressing force of 80 kg / cm 2 . After that, the upper mold 1 and the lower mold 2 are opened to complete the press molding, and the formed glass optical element (not shown) is transported together with the mounting table 8 into the annealing furnace 11 via the transport members 12 and 13 and gradually cooled. Then, the glass optical element as the final product is taken out.

本実施例にあっては、ガラス素材7の下部、即ち、下
型近傍のみが第2成形工程において徐々に冷却されるの
で、上記第1,第2実施例と同様な作用を有してガラス光
学素子が押圧成形される。
In the present embodiment, only the lower part of the glass material 7, that is, only the vicinity of the lower mold, is gradually cooled in the second molding step, so that the glass has the same operation as the first and second embodiments. The optical element is pressed.

本実施例によれば、上記第1,第2実施例と同様に成形
用金型とガラス光学素子との界面に生ずる密着力が低減
され、離型部材等の手段を用いることなく離型できる。
According to this embodiment, the adhesive force generated at the interface between the molding die and the glass optical element is reduced as in the first and second embodiments, and the mold can be released without using means such as a release member. .

さらに、下型あるいは上下両型の温度を変化させる必
要がないので、より短時間に連続して次のガラス素材を
押圧成形することができ、押圧成形のサイクルタイムを
短縮することができる。
Further, since it is not necessary to change the temperature of the lower mold or the upper and lower molds, the next glass material can be continuously pressed in a shorter time, and the cycle time of the press molding can be shortened.

〔発明の効果〕〔The invention's effect〕

以上のように、本発明のガラス光学素子の成形方法に
よれば、ガラス素材を同一冷却速度で押圧成形した後、
ガラス素材における上型近傍と下型近傍との冷却速度に
変化を与えつつ押圧成形する第2成形工程を設けたの
で、ガラス内部に収縮量の違いにより生じる「そり」に
対応した弾性変形が発生するため、この弾性変形により
離型部材等の手段を用いることなく離型することができ
る。従って、離型部材の押圧によってガラス光学素子に
カケ等の発生を防止できるとともに、ガラスのカケが金
型成形面に付着することがなく金型寿命を延命化するこ
とができる。さらに、強い離型力で離型した場合の形状
変形を防止でき、形状精度の向上を図ることができる。
また、離型部材が不用となるため、成形装置の簡易化、
小型化を図ることができる。その結果、形状精度の安定
した高品質なガラス光学素子を大量、安価に製造するこ
とができる。
As described above, according to the method for molding a glass optical element of the present invention, after pressing the glass material at the same cooling rate,
Since the second forming step of pressing and forming while changing the cooling rate between the vicinity of the upper mold and the vicinity of the lower mold in the glass material is provided, elastic deformation corresponding to the "warpage" caused by the difference in the amount of shrinkage occurs inside the glass Therefore, the mold can be released without using means such as a release member due to the elastic deformation. Accordingly, generation of chips or the like on the glass optical element due to pressing of the release member can be prevented, and the life of the mold can be extended without the chips of the glass adhering to the molding surface of the mold. Further, shape deformation when the mold is released with a strong release force can be prevented, and the shape accuracy can be improved.
Also, since the release member is not required, the molding device can be simplified,
The size can be reduced. As a result, high-quality glass optical elements with stable shape accuracy can be manufactured in large quantities at low cost.

【図面の簡単な説明】[Brief description of the drawings]

第1図は、本発明に係るガラス光学素子の成形方法の第
1実施例の実施に使用する成形装置の断面、第2図は、
第1実施例における成形工程を示すグラフ図、第3図
は、本発明に係るガラス光学素子の成形方法の第2実施
例における成形工程を示すグラフ図、第4図は、本発明
に係るガラス光学素子の成形方法の実施に使用する成形
装置の要部を示す断面図、第5図は、従来の成形装置を
示す断面図である。 7……ガラス素材 21……上型 22……下型 23,30……熱電対 24,31……ヒータ 25,32……温度コントローラ
FIG. 1 is a cross-sectional view of a molding apparatus used for carrying out the first embodiment of the method for molding a glass optical element according to the present invention, and FIG.
FIG. 3 is a graph showing a forming step in the first embodiment, FIG. 3 is a graph showing a forming step in the second embodiment of the method for forming a glass optical element according to the present invention, and FIG. FIG. 5 is a cross-sectional view showing a main part of a molding apparatus used for carrying out a method for molding an optical element, and FIG. 5 is a cross-sectional view showing a conventional molding apparatus. 7 Glass material 21 Upper mold 22 Lower mold 23,30 Thermocouple 24,31 Heater 25,32 Temperature controller

フロントページの続き (72)発明者 川村 英司 東京都渋谷区幡ケ谷2丁目43番2号 オ リンパス光学工業株式会社内 (56)参考文献 特開 平2−59449(JP,A) 特開 平1−208334(JP,A)Continuation of the front page (72) Inventor Eiji Kawamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) References JP-A-2-59449 (JP, A) JP-A-1- 208334 (JP, A)

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】成形するガラス素材の転移点温度付近に加
熱した上下一対からなる成形用金型によって、この成形
用金型よりも高い温度に加熱軟化したガラス素材を押圧
成形するガラス光学素子の成形方法において、 上記成形用金型よりも高い温度に加熱軟化したガラス素
材における上型近傍と下型近傍とを同一冷却速度で押圧
成形する第1成形工程と、 上記ガラス素材における上型近傍と下型近傍とを冷却速
度を変化させつつ押圧成形する第2成形工程と、 を有することを特徴とするガラス光学素子の成形方法。
1. A glass optical element for press-molding a glass material heated and softened to a temperature higher than the molding die by a pair of upper and lower molding dies heated near the transition point temperature of the glass material to be molded. In the molding method, a first molding step of press-molding the vicinity of the upper mold and the vicinity of the lower mold in the glass material heated and softened to a temperature higher than the molding die at the same cooling rate, and the vicinity of the upper mold in the glass material. A second molding step of press-molding the vicinity of the lower mold while changing the cooling rate, and a method of molding a glass optical element.
JP1013348A 1989-01-23 1989-01-23 Glass optical element molding method Expired - Fee Related JP2718452B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1013348A JP2718452B2 (en) 1989-01-23 1989-01-23 Glass optical element molding method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1013348A JP2718452B2 (en) 1989-01-23 1989-01-23 Glass optical element molding method

Publications (2)

Publication Number Publication Date
JPH02196039A JPH02196039A (en) 1990-08-02
JP2718452B2 true JP2718452B2 (en) 1998-02-25

Family

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JPH0613414B2 (en) * 1989-02-10 1994-02-23 大日本スクリーン製造株式会社 Aspherical lens manufacturing method and lens molding die
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
JP4758772B2 (en) * 2006-01-19 2011-08-31 富士フイルム株式会社 Mold for molding and molding method
CN114311469A (en) * 2021-12-13 2022-04-12 刘园 TAC lens forming process

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JPH0259449A (en) * 1988-08-23 1990-02-28 Canon Inc Method and device for producing optical element

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