JPH0780687B2 - Lens molding method - Google Patents
Lens molding methodInfo
- Publication number
- JPH0780687B2 JPH0780687B2 JP1186445A JP18644589A JPH0780687B2 JP H0780687 B2 JPH0780687 B2 JP H0780687B2 JP 1186445 A JP1186445 A JP 1186445A JP 18644589 A JP18644589 A JP 18644589A JP H0780687 B2 JPH0780687 B2 JP H0780687B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- molding
- mold
- pressure
- lens material
- 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
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
- C03B2215/00—Press-moulding glass
- C03B2215/72—Barrel presses or equivalent, e.g. of the ring mould type
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はレンズのプレス成形法に係わり、特に形状精度
及び画精度の優れたレンズの成形方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens press molding method, and more particularly to a lens molding method having excellent shape accuracy and image accuracy.
従来の技術 従来のレンズのプレス成形方法を、ガラスの場合につい
て第４図〜第７図を用いて説明する。一般にプレス成形
によってガラスレンズを製造する場合、レンズ素材を所
定の大きさに切断し、ガラス転移点付近の温度まで予備
加熱し、この加熱昇温されたレンズ素材を型閉めしたと
きレンズの完成品とほぼ同一形状となるように加工され
た上型と下型の上下型の間に供給し、所定の温度と圧力
で加圧成形を行っている。2. Description of the Related Art A conventional lens press-molding method for glass will be described with reference to FIGS. Generally, when manufacturing a glass lens by press molding, the lens material is cut into a predetermined size, preheated to a temperature near the glass transition point, and the heated lens material is closed to complete the lens product. It is supplied between an upper die and a lower die, which are processed to have almost the same shape as the above, and pressure molding is performed at a predetermined temperature and pressure.
レンズ素材１の形状は、できる限り簡単な形状が製造工
程あるいは素材の加工の面でも望ましく、例えば第５図
に示されるような素材を所定の幅で切断した円柱体のも
のがある。しかしこの様な素材を用いて成形すると、第
６図に示す素材の角部６が最初に変形し、上型２及び下
型３と角部近傍がなじんでしまい、密閉空間７ができ
る。一旦密閉空間ができると、成形完了時迄密閉空間が
存在し、金型の加工面が素材に十分転写されず不良レン
ズとなる。こういった未転写不良を防止する従来の方法
について第７図を用いて説明する。The shape of the lens material 1 is preferably as simple as possible in terms of the manufacturing process or the processing of the material, and for example, there is a cylindrical body obtained by cutting the material into a predetermined width as shown in FIG. However, when molding is performed using such a material, the corner portion 6 of the material shown in FIG. 6 is first deformed, the upper mold 2 and the lower mold 3 and the vicinity of the corner are fitted, and a closed space 7 is formed. Once a closed space is created, the closed space exists until the completion of molding, and the processed surface of the mold is not sufficiently transferred to the material, resulting in a defective lens. A conventional method for preventing such untransferred defects will be described with reference to FIG.
下型３は連結棒3aを介してベース3bに固定されており、
上型２は連続棒2aを介してピストン棒2bに取り付けられ
ている。素材１は加熱ヒータ８により成形温度まで加熱
される。所望の成形温度に達した時点で、上型２がピス
トン９によって下降し素材と接触する。その後上型が上
下に振動加圧するが、例えばサーボパルサ10を使ってこ
れを実行する。振動加圧は例えば全加圧ストロークの９
割まで行い、残りの１割を定常加圧で成形する。全加圧
ストロークに達したところで通電をやめ、所望の温度に
降温したところで型を開き、冷却後レンズを取り出す。
上記一連の成形プロフィールの中で全加圧ストロークの
９割を振動加圧することにより、従来発生していた未接
触部分がなくなるという効果が開示されている（例えば
特開昭60-246231号公報等）。The lower mold 3 is fixed to the base 3b via the connecting rod 3a,
The upper die 2 is attached to the piston rod 2b via the continuous rod 2a. The raw material 1 is heated to the molding temperature by the heater 8. When the desired molding temperature is reached, the upper mold 2 is lowered by the piston 9 and comes into contact with the material. After that, the upper mold vibrates and presses up and down, and this is executed by using, for example, the servo pulser 10. Vibration pressure is, for example, 9 of the total pressure stroke.
The remaining 10% is molded under constant pressure. When the full pressurization stroke is reached, the power supply is stopped, the temperature is lowered to the desired temperature, the mold is opened, and the lens is taken out after cooling.
By vibrating and pressurizing 90% of the entire pressurizing stroke in the above series of molding profiles, the effect of eliminating the non-contact portion that has been conventionally generated is disclosed (for example, JP-A-60-246231). ).
発明が解決しようとする課題 従来の成形方法にあっては、レンズの形状を決定する上
型が成形途中すなわち加熱加圧工程中においてレンズ素
材と密着，型離れを繰り返すため、その際に空気を巻き
込み、軟化した素材に気泡がたまるという問題があっ
た。又上記上型の挙動により、下型との位置合わせが非
常に難しく、成形レンズの両面の傾きを保証することが
困難であった。又同じく上記した上型の挙動により、上
型の温度が均一でなくなる為レンズ素材の温度分布も不
均一となり、成形レンズに大きなヒケを生ずる原因とな
っていた。In the conventional molding method, since the upper mold that determines the shape of the lens repeats close contact with the lens material and mold release during molding, that is, during the heating and pressing process, air is blown at that time. There was a problem that air bubbles were accumulated in the softened material that was caught. Further, due to the behavior of the upper mold, it is very difficult to align the position with the lower mold, and it is difficult to guarantee the inclination of both surfaces of the molded lens. Also, due to the above-described behavior of the upper mold, the temperature of the upper mold is not uniform, and the temperature distribution of the lens material becomes non-uniform, which causes a large sink mark on the molded lens.
課題を解決するための手段 上記課題を解決するために本発明のレンズの成形方法
は、上型と下型とからなる成形型で、前記上型と下型の
間の空間に供給されたレンズ素材を加圧成形してレンズ
を得る成形方法に於て、冷却中に成形圧力を少なくとも
一回以上零にまで減圧するか零にすることを特徴とする
ものである。上記レンズ材料の線膨張率が100℃〜300℃
で50×10-7／℃以上であることが望ましく、金型とレン
ズ素材が常に密着した状態で成形され、レンズ素材は、
円柱形状が望ましい。Means for Solving the Problems In order to solve the above problems, a lens molding method of the present invention is a molding die including an upper die and a lower die, and a lens supplied to a space between the upper die and the lower die. In a molding method for forming a lens by pressure-molding a material, the molding pressure is reduced to zero at least once or more during cooling. The linear expansion coefficient of the above lens material is 100 ℃ ~ 300 ℃
It is desirable that the temperature is 50 × 10 −7 / ° C. or higher, and the mold and lens material are always in close contact, and the lens material is
A cylindrical shape is desirable.
作用 上記のような構成であれば、金型のレンズ形状転写面と
レンズ素材との間に未接触部分を発生させる事なく成形
でき、又、上下型の軸ズレを防止でき、成形時のレンズ
の不均一な収縮をなくすることができる。Action With the above-mentioned configuration, molding can be performed without generating a non-contact portion between the lens shape transfer surface of the mold and the lens material, and axial misalignment between the upper and lower molds can be prevented, and the lens at the time of molding can be prevented. It is possible to eliminate the non-uniform shrinkage.
実施例 以下第１の一実施例について図面を参照しながら説明す
る。第１図において、上型11は上型ツバ部11cの大きさ
に合わせて座ぐりの入った加圧ステージ15にはめ合わさ
れ、ビス等で固定されている。下型12は下型ツバ部12c
の大きさに合わせて座ぐりの入った成形ステージ16には
め合わされ、ビス等で固定されている。又加圧ステージ
15と成形ステージ16は、上型11と下型12の軸心が一致す
るような位置に正確に調整されており、上型11が上下に
移動した際にも軸心がずれることはない。加圧ステージ
15及び成形ステージ16には図示していないが任意の温度
に調整できる加熱源を内蔵している。更に加圧ステージ
15は、図示していないが例えば油圧ポンプ等により加圧
力が加えられ、上型11に正確に圧力を伝え、任意の位置
に停止することが可能であり、圧力は成形途中に任意の
圧力に減圧、或は零にできるようになっている。Embodiment A first embodiment will be described below with reference to the drawings. In FIG. 1, the upper mold 11 is fitted to a pressure stage 15 having a spot facing according to the size of the upper mold brim portion 11c, and is fixed with screws or the like. Lower mold 12 is lower mold brim 12c
It is fitted to a forming stage 16 having a spot facing according to the size of and is fixed with screws or the like. Another pressure stage
15 and the molding stage 16 are accurately adjusted in such a position that the axes of the upper die 11 and the lower die 12 coincide with each other, and the axes do not shift even when the upper die 11 moves up and down. Pressure stage
Although not shown, the 15 and the molding stage 16 incorporate a heating source that can be adjusted to an arbitrary temperature. Further pressure stage
Although not shown in the figure, a pressure is applied to the upper mold 11 by means of a hydraulic pump, for example, which is not shown in the figure, and it is possible to accurately transmit the pressure to the upper mold 11 and stop it at an arbitrary position. The pressure can be reduced to zero.
以上のように構成された成形装置を用いて、ガラス素材
を成形する方法を説明する。まず一般的な成形プロフィ
ールを第３図に示す。第３図は、横軸に時間、縦軸に温
度をとっている。成形は大きく分けて予備加熱工程，加
熱加圧工程，冷却加圧工程，冷却工程の４工程から成っ
ている。予備加熱工程に於て、まず金型及びレンズ素材
の温度を成形可能な温度まで昇温する。これを予備加熱
工程（Ａ）と称する。金型の温度分布が均一になったと
ころで、金型に加圧力を加えレンズ素材を任意の厚さま
で変形させる。これを加熱加圧工程あるいは均熱加圧工
程（Ｂ）と称する。レンズ素材を任意の厚さまで変形し
終った時点から加圧力を維持した状態で冷却にはいる。
これを冷却加圧工程（Ｃ）と称する。レンズ素材が加圧
に対して変形可能な温度まで冷却加圧を続けた後、加圧
力を開放し、圧力を零にする。そして更に冷却を続け
る。これを冷却工程（Ｄ）と称する。常温になったとこ
ろで金型を開いてレンズを取り出す。以上が一般的な成
形プロフィールーである。A method of molding a glass material using the molding apparatus configured as described above will be described. First, a general molding profile is shown in FIG. In FIG. 3, the horizontal axis represents time and the vertical axis represents temperature. Molding is roughly divided into four steps: preheating step, heating and pressurizing step, cooling and pressurizing step, and cooling step. In the preheating step, first, the temperature of the mold and lens material is raised to a temperature at which molding is possible. This is called a preheating step (A). When the temperature distribution of the mold becomes uniform, pressure is applied to the mold to deform the lens material to an arbitrary thickness. This is called a heating / pressurizing step or a soaking / pressurizing step (B). After the lens material has been deformed to a desired thickness, cooling is started while maintaining the applied pressure.
This is called a cooling / pressurizing step (C). After continuing the cooling and pressurization to a temperature at which the lens material can be deformed by the pressurization, the pressure is released and the pressure is made zero. Then continue cooling. This is called a cooling step (D). At room temperature, open the mold and take out the lens. The above is a general molding profile.
我々の成形方法は、以上に述べたような基本的な工程を
とりながら、前記課題を解決している。すなわち、レン
ズ素材は第５図に示す様な円柱体であり、端面は鏡面で
ある。本実施例では直径5mm×長さ7mmの光学ガラスSF−
８（ガラス転移点420℃、線膨張率100℃〜300℃で90×1
0-7／℃）の円柱体を使用した。このレンズ素材を下型1
2の転写面12aに端面が金型転写面と向き合うように、縦
置きに供給した後加圧ステージが下降し、上型11の転写
面11aとガラス素材13はガラス素材の円周で線接触す
る。このときレンズ素材には、加圧ステージの自重が加
わることになる。この状態で加圧ステージ15及び成形ス
テージ16に内蔵された加熱源に通電し、レンズ素材の温
度が530℃になるまで加熱する。ここまでが前記の予備
加熱工程である。レンズ素材の温度が530℃になった時
点でガラス素材の温度は、1010ポアズとなっている。そ
して次に油圧ポンプにより加圧ステージに圧力が供給さ
れ、上型11がレンズ素材を押圧し始める。この時の圧力
は2kg/mm2以上が良い。上型11が所定の位置まで下降し
た時点で、加圧ステージ15が停止する。ここまでが前記
の加熱加圧工程である。Our molding method solves the above-mentioned problems while taking the basic steps described above. That is, the lens material is a cylindrical body as shown in FIG. 5, and the end surface is a mirror surface. In this embodiment, an optical glass SF-having a diameter of 5 mm and a length of 7 mm is used.
8 (Glass transition point 420 ℃, linear expansion coefficient 100 ℃ ~ 300 ℃ 90 × 1
(0 −7 / ° C.) cylindrical body was used. This lens material is the lower mold 1
The pressure stage descends after vertically supplying so that the end surface of the second transfer surface 12a faces the mold transfer surface, and the transfer surface 11a of the upper mold 11 and the glass material 13 make a line contact on the circumference of the glass material. To do. At this time, the weight of the pressure stage is added to the lens material. In this state, the heating sources built in the pressure stage 15 and the molding stage 16 are energized to heat the lens material until the temperature reaches 530 ° C. Up to this point is the above-mentioned preheating step. When the temperature of the lens material reaches 530 ° C, the temperature of the glass material is 10 10 poise. Then, the pressure is supplied to the pressure stage by the hydraulic pump, and the upper mold 11 starts to press the lens material. The pressure at this time should be 2 kg / mm 2 or more. When the upper mold 11 descends to a predetermined position, the pressure stage 15 stops. The process up to this point is the above-mentioned heating and pressurizing step.
この時のレンズ素材の粘度が109ポアズとなっている。
上型11が所定の位置まで下降した時点では、金型転写面
11a,12aとレンズ素材で囲まれる空間11b,12bが正圧にな
っている為、レンズ素材には金型転写面が完全に転写さ
れていない部分がある。次に冷却加圧工程に入る。すな
わち加圧ステージ15及び成形ステージ16に内蔵された加
熱源への通電を停止し、加圧ステージには加熱加圧工程
と同様に2kg/mm2以上の圧力を圧力ポンプから供給を継
続する。冷却加圧工程中、所定の時間が経過後一旦成形
圧力を零にし、加圧ステージ15を上昇して上型11の転写
面11aとレンズ素材を離型する。前記圧力を零にした時
点で正圧になっていた金型転写面11a,12aとレンズ素材
端面で囲まれる空間11b,12bは常圧に戻る。次に再び加
圧ステージ15を下降し、金型11と転写面11b及び金型12
の熱転写12bをレンズ素材と密着させる。この時転写面1
1a,12aとレンズ素材端面で囲まれる空間11b,12bは、加
熱加圧工程中の空間11b,12bよりもかなり小さい容積と
なっている。又、加熱中の粘度より幾分高い状態である
冷却加圧工程中に圧力を抜く為に、上型11の転写面11a
とレンズ素材を離型した際の気泡のかみ込みに対して、
レンズ表面が影響を受けることもない。次に430℃迄冷
却加圧を行った後圧力供給を停止し、成形圧力を再び零
にする。この時レンズ素材と型は密着した状態を保って
いる。そして冷却工程に入る。すなわち型内のレンズの
温度が常温になるまでレンズ素材と型が密着した状態で
放置しておき、その後加圧ステージを上昇し、型を開い
てレンズを取り出す。冷却中にガラス素材は収縮に伴う
流動により、金型転写面11a,12aとレンズ素材端面で囲
まれる空間11b,12bは更に小さくなりレンズ素材表面に
凹部となって残るがレンズ性能に影響のない大きさにな
る。又、レンズ素材の線膨張率が50×10-7／℃以上であ
れば、ガラス素材の流動が更に大きくなるため、レンズ
表面の凹部はほとんどなくなる。以上の実施例では、冷
却加圧工程中に成形圧力を零にしたが、レンズ素材の形
状あるいは大きさによっては、冷却加圧工程中に減圧す
るだけで、金型転写面11a,12aとレンズ素材端面で囲ま
れる空間11b,12bは常圧に戻るので、減圧するだけでも
良い。また冷却中に、上型とレンズ素材を離型せず、上
型とレンズ素材が密着した状態で加圧力を減圧するか零
にすることによって、更に転写性を向上することができ
る。本実施例では、冷却加圧工程中に所定の時間が経過
後、一回圧力を零にしたが、レンズ形状、寸法によって
は二回以上実施すれば、効果が大きい。又、冷却加圧時
の収縮量によって、圧力をぬくタイミングを決めても良
い。更に本実施例では冷却加圧工程終了後、レンズ素材
と型は密着した状態を保ったが、加圧ステージを上昇し
て上型11とレンズを離した状態で冷却工程に入っても良
い。At this time, the viscosity of the lens material is 10 9 poise.
When the upper mold 11 descends to the specified position, the mold transfer surface
Since the spaces 11b and 12b surrounded by 11a and 12a and the lens material have a positive pressure, the lens material has a portion where the mold transfer surface is not completely transferred. Next, the cooling / pressurizing step is started. That is, the power supply to the heating source built in the pressurizing stage 15 and the molding stage 16 is stopped, and the pressure of 2 kg / mm 2 or more is continuously supplied to the pressurizing stage from the pressure pump as in the heating and pressurizing step. During the cooling and pressurizing step, after a predetermined time has elapsed, the molding pressure is once made zero, and the pressurizing stage 15 is raised to release the transfer surface 11a of the upper mold 11 and the lens material. The spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surface, which have been positive pressure when the pressure is reduced to zero, return to normal pressure. Next, the pressure stage 15 is lowered again, and the mold 11, the transfer surface 11b and the mold 12 are
Attach the thermal transfer 12b of to the lens material. Transfer surface 1 at this time
Spaces 11b and 12b surrounded by 1a and 12a and the lens material end surface have a volume considerably smaller than the spaces 11b and 12b during the heating and pressing process. In addition, in order to release the pressure during the cooling and pressurizing process, which is slightly higher than the viscosity during heating, the transfer surface 11a of the upper mold 11 is
And against the inclusion of air bubbles when releasing the lens material,
The lens surface is not affected either. Next, after cooling and pressurizing to 430 ° C., the pressure supply is stopped and the molding pressure is made zero again. At this time, the lens material and the mold are kept in close contact with each other. Then, the cooling process starts. That is, the lens material and the mold are left in close contact with each other until the temperature of the lens in the mold reaches room temperature, and then the pressure stage is raised to open the mold and take out the lens. During cooling, the glass material flows due to contraction, and the spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the end surface of the lens material become even smaller and remain as concave portions on the lens material surface, but this does not affect lens performance. It becomes big. Further, when the linear expansion coefficient of the lens material is 50 × 10 −7 / ° C. or more, the flow of the glass material is further increased, so that the concave portions on the lens surface are almost eliminated. In the above examples, the molding pressure was set to zero during the cooling / pressurizing step, but depending on the shape or size of the lens material, it is only necessary to reduce the pressure during the cooling / pressurizing step, and the mold transfer surfaces 11a, 12a and the lens. Since the spaces 11b and 12b surrounded by the material end face return to normal pressure, it is only necessary to reduce the pressure. Further, during the cooling, the transferability can be further improved by not releasing the upper mold and the lens material but reducing the pressure to zero while the upper mold and the lens material are in close contact with each other. In this embodiment, the pressure is made zero once after a predetermined time has passed during the cooling and pressurizing step, but depending on the shape and size of the lens, the effect can be great if it is carried out twice or more. Also, the timing for removing the pressure may be determined by the amount of contraction during cooling and pressurization. Further, in the present embodiment, after the cooling and pressurizing step is completed, the lens material and the mold are kept in close contact with each other, but the cooling step may be started with the pressing stage raised to separate the upper mold 11 from the lens.
以下第２の実施例について図面を参照しながら説明する
と、第２図において、本発明の成形方法に係わる成形装
置は、上型11と下型12の軸ずれをなくし、かつ所定のレ
ンズ厚になるように任意の高さに調整した胴型14と前記
上型，下型及び胴型で囲まれる空間に供給されたレンズ
素材13とを有している。レンズ素材は第５図に示すよう
な円柱状であり、端面は鏡面である。この素材を両端面
が上下金型の転写面に接するように金型内に供給する。
15は加熱源を内蔵した加圧ステージであり、図示してい
ないが例えば油圧ポンプ等により加圧力を加圧ステージ
に伝えている。また加圧ステージは、成形途中に任意の
圧力に減圧あるいは零にできるようになっている。16は
加熱源を内蔵した成形ステージであり、固定されてい
る。A second embodiment will be described below with reference to the drawings. Referring to FIG. 2, the molding apparatus according to the molding method of the present invention eliminates axial misalignment between the upper mold 11 and the lower mold 12 and has a predetermined lens thickness. It has a barrel mold 14 adjusted to have an arbitrary height and a lens material 13 supplied to a space surrounded by the upper mold, the lower mold and the barrel mold. The lens material has a cylindrical shape as shown in FIG. 5, and the end surface is a mirror surface. This material is supplied into the mold so that both end surfaces contact the transfer surfaces of the upper and lower molds.
Reference numeral 15 is a pressurizing stage having a built-in heating source, and although not shown, the pressurizing stage is transmitted to the pressurizing stage by, for example, a hydraulic pump or the like. Further, the pressurizing stage can reduce the pressure to zero or reduce it to zero during molding. Reference numeral 16 is a molding stage having a built-in heating source, which is fixed.
以上のように構成された成形装置を用いてガラス素材を
成形する方法を説明する。素材は直径8mm×長さ10mmの
光学ガラスSF−８（ガラス転移点420℃、線膨張率100℃
〜300℃で90×10-7／℃）の円柱体であり、この素材を
下型12の転写面12aに縦置きに供給し、その後上型11を
胴型14に合わせて挿入し、レンズ素材に接触させる。そ
の後加熱源に通電してレンズ素材の温度を530℃に加熱
する（予備加熱工程）。レンズ素材の温度が530℃にな
った時点で、レンズ素材の粘度は1010ポアズとなってい
る。次に加圧ステージに圧力が供給され上型11が素材を
押圧し始める（加熱加圧工程）。この時の圧力は2kg/mm
2以上が良い。レンズ素材が上型と下型とからなる加工
型と、上型と下型を位置決めする胴型と、前記上型と下
型と胴型で囲まれる空間に供給された際にできた上型11
と胴型14の間の隙間が加熱加圧中に完全になくなり、密
着するまでのストローク長を全加熱加圧ストロークと言
う。全加熱加圧ストロークを押圧したところで加熱加圧
工程を終了する。この時のレンズ素材の粘度は109ポア
ズとなっている。全加熱加圧ストロークを押圧した時点
すなわち、加熱加圧工程の終了時点では金型転写面11a,
12aとレンズ素材端面で囲まれる空間11b,12bが正圧にな
っている為、レンズ素材には金型転写面が完全に転写さ
れていない部分がある。次に、冷却加圧工程に入る。冷
却加圧工程中、所定の時間が経過後一旦成形圧力を零に
し、加圧ステージ15を上昇して上型ツバ部11cから離
す。前記圧力を零にした時点で正圧になっていた金型転
写面11a,12aとレンズ素材端面で囲まれる空間11b,12bは
常圧に戻る。次に再び加圧ステージ15を下降し、金型ツ
バ部11cと密着させる。この時上型ツバ部11cと胴部14の
端面は密着している。この時転写面11a,12aとレンズ素
材端面で囲まれる空間11b,12bは、加熱加圧工程中の空
間11b,12bよりもかなり小さい容積となっている。次に4
30℃迄冷却加圧を行う。冷却加圧によって、レンズ素材
の流動により、金型転写面11a,12aとレンズ素材端面で
囲まれる空間11b,12bは更に小さくなりレンズ素材表面
に凹部となって残るがレンズ性能に影響のない大きさに
なる。又、レンズ素材の線膨張率が50×10-7／℃以上で
あれば、レンズ素材の流動が更に大きくなるため、レン
ズ表面に凹部はほとんどなくなる。その後圧力供給を停
止し成形圧力を零にする。そして型内のレンズの温度が
室温になったところで型を開き、レンズを取り出す。本
実施例では、加圧ステージと上型ツバ部が固定されてい
ず、型と素材が常に密着した状態で成形されるために、
転写性が非常に向上する。A method of molding a glass material using the molding apparatus configured as described above will be described. The material is optical glass SF-8 with a diameter of 8 mm and a length of 10 mm (glass transition point 420 ° C, linear expansion coefficient 100 ° C.
It is a columnar body of 90 × 10 -7 / ℃ at ~ 300 ℃), and this material is supplied vertically to the transfer surface 12a of the lower mold 12, then the upper mold 11 is inserted in line with the body mold 14, and the lens Touch the material. After that, the heating source is energized to heat the temperature of the lens material to 530 ° C (preheating step). When the temperature of the lens material reaches 530 ° C, the viscosity of the lens material is 10 10 poise. Next, pressure is supplied to the pressure stage, and the upper mold 11 starts to press the material (heating and pressing step). The pressure at this time is 2 kg / mm
2 or more is good. The lens mold material is a processing mold including an upper mold and a lower mold, a barrel mold for positioning the upper mold and the lower mold, and an upper mold formed when the lens material is supplied to the space surrounded by the upper mold, the lower mold, and the barrel mold. 11
The stroke length until the gap between the mold body 14 and the die 14 completely disappears during heating and pressurization is called the total heating and pressurizing stroke. When the entire heating / pressurizing stroke is pressed, the heating / pressurizing step is ended. At this time, the viscosity of the lens material is 10 9 poise. At the time of pressing the entire heating / pressurizing stroke, that is, at the end of the heating / pressurizing process, the mold transfer surface 11a,
Since the spaces 11b and 12b surrounded by 12a and the end surface of the lens material have a positive pressure, the lens material has a portion where the mold transfer surface is not completely transferred. Next, a cooling / pressurizing step is started. During the cooling / pressurizing step, the molding pressure is once made to be zero after a lapse of a predetermined time, and the pressing stage 15 is lifted and separated from the upper mold brim portion 11c. The spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surface, which have been positive pressure when the pressure is reduced to zero, return to normal pressure. Next, the pressure stage 15 is lowered again to bring it into close contact with the mold flange 11c. At this time, the upper mold flange portion 11c and the end surface of the body portion 14 are in close contact with each other. At this time, the spaces 11b and 12b surrounded by the transfer surfaces 11a and 12a and the end surface of the lens material have a much smaller volume than the spaces 11b and 12b during the heating and pressing process. Then 4
Cool and pressurize to 30 ℃. Due to the flow of the lens material due to the cooling and pressurization, the spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the end surface of the lens material are further reduced and remain as concave portions on the surface of the lens material, but the size does not affect the lens performance. It will be Further, when the linear expansion coefficient of the lens material is 50 × 10 −7 / ° C. or more, the flow of the lens material is further increased, so that there are almost no concave portions on the lens surface. After that, the pressure supply is stopped and the molding pressure is made zero. Then, when the temperature of the lens in the mold reaches room temperature, the mold is opened and the lens is taken out. In this embodiment, the pressure stage and the upper mold brim are not fixed, and the mold and the material are molded in a state where they are always in close contact with each other.
Transferability is greatly improved.
以上の実施例では、冷却加圧工程中で成形圧力を零にし
たが、レンズ素材の大きさによっては減圧するだけで、
金型転写面11a,12aとレンズ素材端面で囲まれる空間11
b,12bは常圧に戻るので、減圧するだけでも良い。又、
レンズ厚を調節する胴型４は、第２図のように上、下型
と接している必要はなく、加圧ステージ15及び成形ステ
ージ16と密着する上、下型ツバ部11c,12cの外側に、リ
ング状の胴型あるいはブロック状のスペーサを設けて加
圧ステージ15と成形ステージ16の間隔を調整する方法で
も良い。又冷却加圧工程及び冷却工程を別ステージに移
動して行っても良い。In the above examples, the molding pressure was set to zero during the cooling and pressurizing process, but depending on the size of the lens material, only the pressure is reduced.
Space 11 surrounded by mold transfer surfaces 11a and 12a and lens material end surface
Since b and 12b return to normal pressure, it is sufficient to reduce the pressure. or,
The body mold 4 for adjusting the lens thickness does not have to be in contact with the upper and lower molds as shown in FIG. 2, but is in close contact with the pressure stage 15 and the molding stage 16, and is outside the lower mold brim portions 11c and 12c. Alternatively, a ring-shaped body or block-shaped spacer may be provided to adjust the distance between the pressure stage 15 and the molding stage 16. Alternatively, the cooling / pressurizing step and the cooling step may be moved to different stages.
発明の効果 本発明は以上に説明した成形方法であるために、以下に
記載されるような効果を奏する。EFFECTS OF THE INVENTION Since the present invention is the molding method described above, it has the following effects.
成形途中に於いて、冷却加圧工程で一旦圧力供給を停止
し、加圧ステージを上昇させ上型と離して成形圧力を零
にし、型内の圧力を常圧に戻すことにより、従来発生し
ていた空気の巻き込みによる成形不良がなくなり、形状
精度，面精度共に優れたレンズを成形できる。また上下
の金型とレンズ素材が冷却工程終了時点まで常に密着し
た状態であるために、上下型の精度をそのままレンズ素
材に転写できる。又、軸ズレも防止できる。更に上下の
金型とレンズ素材が加熱加圧工程終了時点まで常に密着
した状態であるために、レンズの両面の傾きを成形ステ
ージと加圧ステージ或は、金型と胴型によって容易に保
障できる。金型とレンズ素材が密着していることによ
り、金型からレンズ素材に伝わる熱の温度分布が均一で
あり、レンズ素材の成形途中の変形、及び冷却時の収縮
が不均一とならないために形状精度の良いレンズが得ら
れる。In the middle of molding, pressure supply is temporarily stopped in the cooling and pressurizing process, the pressure stage is raised to separate from the upper mold to reduce the molding pressure to zero, and the pressure inside the mold is returned to normal pressure. The defective molding due to the entrainment of air is eliminated, and a lens with excellent shape accuracy and surface accuracy can be molded. Further, since the upper and lower molds and the lens material are always in close contact with each other until the end of the cooling process, the accuracy of the upper and lower molds can be directly transferred to the lens material. In addition, axial misalignment can be prevented. Further, since the upper and lower molds and the lens material are in close contact with each other until the end of the heating and pressing process, the inclination of both sides of the lens can be easily ensured by the molding stage and the pressing stage or the mold and the barrel mold. . Since the mold and lens material are in close contact with each other, the temperature distribution of heat transferred from the mold to the lens material is uniform, and the shape of the lens material is not deformed during molding or contracted during cooling. An accurate lens can be obtained.
レンズ素材の線膨張率が100℃〜300℃で50×10-7／℃以
上であれば、冷却加圧成形の時、金型転写面の形状とレ
ンズ素材の形状のわずかなずれをなくすることができ
る。If the linear expansion coefficient of the lens material is 100 x 300 ℃ and 50 x 10 -7 / ℃ or more, eliminate the slight deviation between the shape of the mold transfer surface and the shape of the lens material during cooling and pressure molding. be able to.
第１図と第２図は本発明の成形方法を実現するための成
形装置の断面図、第３図は一般的な成形プロフィールを
示した図、第４図〜第７図は従来の成形装置及びレンズ
素材の断面図である。 11……上型、11a……金型転写面、11b……空間、11c…
…上型ツバ部、12c……下型ツバ部、12……下型、12a…
…金型転写面、12b……空間、13……レンズ素材、14…
…胴型、15……加圧ステージ、16……成形ステージ。1 and 2 are sectional views of a molding apparatus for realizing the molding method of the present invention, FIG. 3 is a view showing a general molding profile, and FIGS. 4 to 7 are conventional molding apparatuses. FIG. 3 is a cross-sectional view of a lens material. 11 ... Upper mold, 11a ... Mold transfer surface, 11b ... Space, 11c ...
… Upper mold brim part, 12c …… Lower mold brim part, 12 …… Lower mold, 12a…
… Mold transfer surface, 12b …… Space, 13 …… Lens material, 14…
… Body type, 15 …… Pressure stage, 16 …… Molding stage.
Claims (4)
上型と下型の間の空間に供給されたレンズ材料を加圧し
てレンズを成形するレンズの成形方法であって、 前記上型または下型と、前記レンズ材料とは、加圧初期
において、両者の間に空間部を形成する形状関係を有し
ており、 前記成形型による前記レンズ材料の加熱加圧工程終了
後、冷却加圧工程中において、成形型による前記レンズ
材料への加圧力を、前記レンズ材料と前記上型及び下型
とを常に接触させつつ減圧、加圧のサイクルを複数回繰
り返すことを特徴とするレンズの成形方法。1. A method of molding a lens, which comprises molding a lens by using a molding die composed of an upper die and a lower die, and pressurizing a lens material supplied to a space between the upper die and the lower die. The upper mold or the lower mold and the lens material have a shape relationship in which a space is formed between them in the initial stage of pressing, and after the heating / pressurizing step of the lens material by the molding die is completed. In the cooling / pressurizing step, the pressure applied to the lens material by the molding die is characterized in that a cycle of depressurization and pressurization is repeated a plurality of times while always contacting the lens material with the upper mold and the lower mold. Lens molding method.
少なくとも一回以上零にまで減圧することを特徴とする
請求項１記載のレンズの成形方法。2. The method of molding a lens according to claim 1, wherein the pressure is reduced to zero at least once in the pressure reduction and pressure cycles.
×10-7／℃以上であることを特徴とする請求項１または
２のいずれかに記載のレンズの成形方法。3. The linear expansion coefficient of the lens material is 50 at 100 ° C to 300 ° C.
The method for molding a lens according to claim 1 or 2, characterized in that it is not less than × 10 -7 / ° C.
の少なくとも一方は凹面を有し、前記円柱形状のレンズ
材料の両端面が上型、下型に対向するように成形型内に
供給されることを特徴とする請求項１または２のいずれ
かに記載のレンズの成形方法。4. The lens material has a cylindrical shape, and at least one of the upper die and the lower die has a concave surface, and the molding die is such that both end surfaces of the cylindrical lens material face the upper die and the lower die. The method for molding a lens according to claim 1, wherein the lens is supplied inside.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1186445A JPH0780687B2 (en) | 1989-07-19 | 1989-07-19 | Lens molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1186445A JPH0780687B2 (en) | 1989-07-19 | 1989-07-19 | Lens molding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0350126A JPH0350126A (en) | 1991-03-04 |
| JPH0780687B2 true JPH0780687B2 (en) | 1995-08-30 |
Family
ID=16188577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1186445A Expired - Fee Related JPH0780687B2 (en) | 1989-07-19 | 1989-07-19 | Lens molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0780687B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3060773B2 (en) * | 1993-03-08 | 2000-07-10 | 松下電器産業株式会社 | Optical element molding material and molding method |
| EP0648712B1 (en) * | 1993-10-08 | 1999-09-15 | Matsushita Electric Industrial Co., Ltd. | Press moulding method for forming an optical element |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61251529A (en) * | 1985-04-30 | 1986-11-08 | Olympus Optical Co Ltd | Method of high precision molding for glass optical part |
-
1989
- 1989-07-19 JP JP1186445A patent/JPH0780687B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0350126A (en) | 1991-03-04 |
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