JP2616029B2 - Lens molding method - Google Patents
Lens molding methodInfo
- Publication number
- JP2616029B2 JP2616029B2 JP1203317A JP20331789A JP2616029B2 JP 2616029 B2 JP2616029 B2 JP 2616029B2 JP 1203317 A JP1203317 A JP 1203317A JP 20331789 A JP20331789 A JP 20331789A JP 2616029 B2 JP2616029 B2 JP 2616029B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- molding
- pressure
- lens material
- lens
- 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
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)
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
度及び面精度の優れたレンズの成形方法に関するもので
ある。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of pressing a lens, and more particularly to a method of forming a lens having excellent shape accuracy and surface 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。2. Description of the Related Art A conventional lens press forming method for glass will be described with reference to FIGS. 4 to 7. FIG.
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２、下型３の上下型の間に供
給し、所定の温度で加圧成形を行っている。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３図に示される
ような棒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４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５
図を用いて説明する。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 when the mold is closed. Is supplied between the upper and lower dies of the upper die 2 and the lower die 3 which have been processed so as to have substantially the same shape as the above, and pressure molding is performed at a predetermined temperature. The shape of the lens material 1 is desirably as simple as possible in terms of the manufacturing process or the processing of the material. For example, there is a cylindrical material obtained by cutting a rod material into a predetermined width as shown in FIG.
However, when molding is performed using such a material, the corners 6 of the material shown in FIG. 4 are deformed first, and the vicinity of the corners is adapted to the upper mold 2 and the lower mold 3, thereby forming a closed space 7. Once the closed space is formed, 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 is described in the fifth section.
This will be described with reference to the drawings.
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は連結棒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割まで行ない、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）。The lower die 3 is fixed to a base 3b via a connecting rod 3a, and the upper die 2 is attached to a piston rod 2b via a connecting rod 2a. The material 1 is heated by a heater 8 to a molding temperature. 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 performed using, for example, the servo pulser 10. Vibration pressing is performed, for example, up to 90% of the total pressing stroke, and the remaining 10% is formed by steady pressing.
When the entire pressurizing stroke is reached, the power supply is stopped, and when the temperature is lowered to a desired temperature, the mold is opened, and after cooling, the lens is taken out. An effect is disclosed in which 90% of the entire pressurizing stroke is vibrated and pressurized in the above-described series of forming profiles, thereby eliminating the non-contact portion which has conventionally occurred (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障することが
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。Problems to be Solved by the Invention In the conventional molding method, the upper mold that determines the shape of the lens repeatedly adheres to the lens material during molding, that is, during the heating and pressurizing step, and repeatedly releases the mold. There is a problem that air bubbles accumulate in the entangled and softened material. In addition, due to the behavior of the upper mold, it is very difficult to align with the lower mold, and it is difficult to guarantee the inclination of both sides of the molded lens. Also, due to the behavior of the upper mold as described above,
Since the temperature of the upper mold becomes non-uniform, the temperature distribution of the lens material becomes non-uniform, which causes large sink marks 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する方法に
於て、加熱加圧工程終了後、成形圧力を少なくとも一回
以上減圧するかもしくは零にし、冷却加圧工程中に成形
圧力を少なくとも一回以上減圧するかもしくは零にする
ことを特徴とするものである。金型とレンズ素材が常に
密着した状態で成形されることが望ましく、成形型の転
写面の半径Rmと上型と下型の空間に供給されたレンズ素
材の前記転写面に対向する面の半径Rgの関係がRg＞Rmで
ありレンズ素材は、円柱形状であるとき特に有効であ
る。Means for Solving the Problems In order to solve the above problems, a method of forming a lens according to the present invention is a method of forming a lens comprising an upper mold and a lower mold, wherein a lens supplied to a space between the upper mold and the lower mold. In the method of pressure-forming a material, after the heating / pressing step is completed, the forming pressure is reduced at least once or zero, and during the cooling / pressing step, the forming pressure is reduced at least once or zero. It is characterized by the following. It is desirable that the mold and the lens material are always molded in close contact with each other, and the radius Rm of the transfer surface of the molding die and the radius of the surface of the lens material supplied to the space of the upper die and the lower die facing the transfer surface It is particularly effective when the relationship of Rg is Rg> Rm and the lens material has a cylindrical shape.
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。Function With the above-described 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 the axial displacement of the upper and lower molds can be prevented. Uneven shrinkage can be eliminated.
実施例 以下本発明の第一の一実施例について図面を参照しな
がら説明すると、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、或いは零にできるよ
うになっている。Embodiment A first embodiment of the present invention will be described below with reference to the drawings. In FIG.
Pressurized stage 15 with counterbore according to size of 11c
And fixed with screws or the like. The lower mold 12 is fitted to a molding stage 16 having a counterbore in accordance with the size of the lower mold flange 12c, and is fixed with screws or the like.
The pressing stage 15 and the molding stage 16 are composed of the upper die 11 and the lower die
The position of the axis is accurately adjusted so that the axes of 12 coincide with each other, and the axis does not shift even when the upper die 11 moves up and down. Although not shown, a heating source that can be adjusted to an arbitrary temperature is built in the pressing stage 15 and the molding stage 16. Further, although not shown, a pressing force is applied to the pressure stage 15 by, for example, a hydraulic pump or the like, and the pressure is accurately transmitted to the upper mold 11 and can be stopped at an arbitrary position. The pressure can be reduced to an arbitrary pressure or 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
成形プロフィールである。A method for forming a glass material using the forming apparatus configured as described above will be described. First, a general molding profile is shown in FIG. FIG. 3 shows time on the horizontal axis and temperature on the vertical axis. Molding is roughly divided into a preheating step,
It consists of four steps: a heating and pressing step, a cooling and pressing step, and a cooling step. In the preheating step, first, the temperature of the mold and the lens material is raised to a moldable temperature. 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 referred to as a heating and pressing step or a soaking and pressing step (B). From the time when the lens material has been deformed to an arbitrary thickness, cooling is started while maintaining the pressing force. This is called a cooling and pressurizing step (C). After continuing cooling and pressurizing to a temperature where the lens material can be deformed by pressurizing,
Release the pressure and reduce the pressure to zero. And further cooling is continued. This is called a cooling step (D). When the temperature reaches 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。Our molding method solves the above-mentioned problem while taking the basic steps as described above.
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4.5mm×長さ5
mmの光学ガラスSF−６（ガラス転移点421℃、線膨張率1
00℃〜300℃で97×10-7/℃）の円柱体を使用した。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, the diameter is 4.5 mm × length 5
mm optical glass SF-6 (glass transition point 421 ° C, linear expansion coefficient 1
A cylindrical body of 97 × 10 −7 / ° C. at 00 ° C. to 300 ° C.) was used.
このレンズ素材を下型12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、10
10ポアズとなっている。This lens material is supplied vertically to the transfer surface 12a of the lower mold 12 so that the end surface faces the mold transfer surface, and then the pressing stage is lowered, and the transfer surface 11a of the upper mold 11 and the glass material 13 are made of a glass material. Line contact at the circumference of. At this time, the lens material
The weight of the pressure stage is added. In this state, power is supplied to a heating source built in the pressure stage 15 and the molding stage 16 to heat the lens material until the temperature of the lens material reaches 530 ° C. This is the preheating step. When the temperature of the lens material reaches 530 ° C, the temperature of the glass
10 poises.
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。すなわち
この時点から加熱加圧工程が始まる。この時の圧力は2k
g/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。ここまでが加熱加圧
工程である。この時のレンズ素材の粘度は109ポアズと
なっている。加熱加圧工程終了時点は、レンズ素材に金
型転写面が完全に転写されていない部分があり閉じた空
間となっており、成形圧力によって内圧が高くなってい
る。加熱加圧工程終了時点で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。Then, pressure is supplied to the pressure stage by the hydraulic pump, and the upper mold 11 starts pressing the lens material. That is, the heating and pressing step starts from this point. The pressure at this time is 2k
g / mm 2 or more is good. The pressurizing stage 15 stops when the upper mold 11 descends to a predetermined position. This is the heating and pressing step. The viscosity of the lens material at this time is 10 9 poise. At the end of the heating and pressurizing step, there is a portion where the mold transfer surface is not completely transferred to the lens material, and the space is a closed space, and the internal pressure is increased by the molding pressure. At the end of the heating and pressing step, the molding pressure is temporarily reduced to zero, the pressing stage 15 is raised, and the transfer surface 11a of the upper die 11 and the lens material are released.
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の転写面12bをレンズ素材と密着さ
せる。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、加熱加圧工程終了時点の空間11b,12b
よりも、小さい容積となっているか、或いはほとんどな
くなっている。The spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the end surfaces of the lens material, which were positive when the pressure was reduced to zero, return to normal pressure. Next, the pressing stage 15 is lowered again to bring the mold 11 and the transfer surface 11b and the transfer surface 12b of the mold 12 into close contact with the lens material. At this time, the spaces 11b and 12b surrounded by the transfer surfaces 11a and 12a and the end surface of the lens material are the spaces 11b and 12b at the end of the heating and pressing step.
The volume is smaller or almost eliminated.
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の供給を継続する。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。Next, a cooling and pressurizing step is started. That is, the power supply to the heating source built in the pressure stage 15 and the molding stage 16 is stopped, and the pressure stage is set at 2 kg / mm 2 , as in the heating and pressing step.
Supply of the above pressure from the pressure pump is continued. During the cooling and pressurizing step, the molding pressure is temporarily reduced to zero after a predetermined time has elapsed,
The pressure stage 15 is raised to release the transfer surface 11a of the upper mold 11 and the lens material.
前記圧力を零にする直前に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。Immediately before the pressure is reduced to zero, the spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surfaces, which have been positive, return to normal pressure.
次に再び加圧ステージ15を下降し、金型11と転写面11
b及び金型12の転写面12bをレンズ素材と密着させる。こ
の時転写面11a,12aは、レンズ素材に完全に転写され、
冷却加圧工程開始直前のレンズ素材の端面で囲まれる空
間11b,12bは、ほとんどなくなっている。又、加熱中の
粘度より幾分高い粘度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。Next, the pressing stage 15 is lowered again, and the mold 11 and the transfer surface 11 are moved.
b and the transfer surface 12b of the mold 12 are brought into close contact with the lens material. At this time, the transfer surfaces 11a and 12a are completely transferred to the lens material,
The spaces 11b and 12b surrounded by the end surfaces of the lens material immediately before the start of the cooling and pressurizing step are almost eliminated. Also, in order to release pressure during the cooling and pressurizing step, which is a somewhat higher viscosity state than the viscosity during heating, against the entrapment of bubbles when the transfer surface 11a of the upper mold 11 and the lens material are released, The lens surface is not affected.
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。加熱加圧工程終
了後、成形圧力を抜くことによって金型転写面11a,12a
とレンズ素材端面で囲まれる空間11b,12bはかなり小さ
くなっており、さらに冷却加圧工程中に成形圧力を抜く
ことによって空間11b,12bはほとんどの場合なくなって
いる。まれに、冷却加圧工程中に成形圧力を抜くことに
よってなくならなかったレンズ素材端面の凹部は、冷却
加圧工程中にガラス素材の収縮に伴う流動により、更に
小さくなりほぼ完全に金型面が転写される。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
材の収縮による流動が十分に得られるため、レンズ表面
の凹部はなくなり易くなる。Next, after cooling and pressurizing to 430 ° C, the pressure supply was stopped,
The molding pressure is set to zero again. At this time, the lens material and the mold are kept in close contact with each other. Then, a cooling process is started. That is, the lens material and the mold are left in contact with each other until the temperature of the lens in the mold reaches room temperature, and then the pressure stage is raised, the mold is opened, and the lens is taken out. After completion of the heating and pressurizing step, the mold transfer surfaces 11a and 12a
The spaces 11b and 12b surrounded by the lens material end faces are considerably small, and the spaces 11b and 12b are almost completely eliminated by releasing the molding pressure during the cooling and pressurizing step. In rare cases, the concave portion of the lens material end face that has not been removed by releasing the molding pressure during the cooling and pressurizing process is further reduced by the flow accompanying the shrinkage of the glass material during the cooling and pressurizing process, and almost completely becomes the mold surface. Is transferred. If the coefficient of linear expansion of the lens material is 50 × 10 −7 / ° C. or more, sufficient flow due to shrinkage of the glass material can be obtained, so that the concave portion on the lens surface is easily eliminated.
以上の実施例では、加熱加圧工程終了時点と、冷却加
圧工程中に各々１回ずつ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、加熱加圧工程終
了時点と、冷却加圧工程中に各々減圧するだけで、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。In the above embodiments, the molding pressure was set to zero each time during the heating and pressing step and once during the cooling and pressing step, however, depending on the shape or size of the lens material, The spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surfaces only by reducing the pressure during the cooling and pressurizing process, respectively.
Since the pressure returns to normal pressure, the pressure may be reduced.
更に、上型11とレンズ素材は密着したままで成形圧力
を零にするかもしくは減圧すれば、レンズ素材の熱分布
やエアーの巻き込み防止の点で望ましい。Further, it is desirable to reduce the molding pressure to zero or reduce the pressure while keeping the upper mold 11 and the lens material in close contact with each other in terms of heat distribution of the lens material and prevention of air entrainment.
本実施例のように、上型11とレンズ素材を成形圧力を
零にする際に離型すると、エアーの巻き込みが発生し、
レンズ素材表面の特に金型転写面が転写された良好な面
に小さな凹部が発生する場合があるが、冷却加圧工程時
に成形圧力を零にすることによって、凹部は完全になく
なるかあるいは、レンズ性能に影響のない大きさにな
る。As in the present embodiment, when the upper mold 11 and the lens material are released when the molding pressure is reduced to zero, air entrainment occurs,
Small recesses may occur on the surface of the lens material, especially on the good surface where the mold transfer surface is transferred. However, by setting the molding pressure to zero during the cooling and pressurizing step, the recesses are completely eliminated or the lens The size does not affect the performance.
本実施例では、加熱加圧工程終了時点及び、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。In this embodiment, at the end of the heating and pressurizing step, and after a predetermined time has elapsed during the cooling and pressurizing step, the pressure is reduced to zero once,
Depending on the shape and size of the lens, the effect is great if it is performed twice or more. Further, the timing for removing the pressure may be determined according to the amount of contraction during cooling and pressurization.
以下第二の一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。Hereinafter, a second embodiment will be described with reference to the drawings. In FIG. 2, a molding apparatus according to the molding method of the present invention eliminates axial displacement between the upper mold 11 and the lower mold 12 and has a predetermined lens thickness. And a lens material 13 supplied to a space surrounded by the upper mold, the lower mold, and the mold.
レンズ素材は第５図に示すような円柱体であり、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。The lens material is a cylindrical body as shown in FIG. 5, and the end surface is a mirror surface. This material is supplied into the mold so that both end faces are in contact with the transfer surfaces of the upper and lower molds. Reference numeral 15 denotes a pressurizing stage having a built-in heating source, which transmits a pressing force to the pressurizing stage by a hydraulic pump or the like (not shown). The pressure stage can be depressurized to an arbitrary pressure or reduced to zero during molding. Reference numeral 16 denotes 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。A method of forming a glass material using the forming apparatus configured as described above will be described.
素材は直径5mm×長さ6mmの光学ガラスSF−８（ガラス
転移点420℃、線膨張率100℃〜300℃で90×10/℃）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。The material is a cylindrical body of optical glass SF-8 (diameter 5mm x length 6mm, glass transition point 420 ° C, coefficient of linear expansion 90 × 10 / ° C at 100 ° C to 300 ° C). It is supplied vertically to the surface 12a, and then the upper mold 11 is inserted in conformity with the barrel mold 14, and brought into contact with the lens material. Thereafter, the heating source is energized to heat the temperature of the lens material to 530 ° C. (preliminary heating step). When the temperature of the lens material reaches 530 ° C., the viscosity of the lens material is 10 10 poise.
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）。Next, pressure is supplied to the pressing stage, and the upper mold 11 starts pressing the material (heating and pressing step).
この時の圧力は2kg/mm2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、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。加熱加圧工程終了後所定の時間が
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。前記圧力を零にする直前、
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。The pressure at this time is preferably 2 kg / mm 2 or more. A processing die composed of an upper die and a lower die, a barrel die for positioning the upper die and the lower die, and an upper die formed when supplied to a space surrounded by the upper die, the lower die, and the die. The length of the stroke from when the gap between the cylinder die 11 and the die 14 completely disappears during the heating and pressurizing until the gap is brought into close contact is called the total heating and pressurizing stroke. When the entire heating / pressing stroke is pressed, the heating / pressing process is completed. The viscosity of the lens material at this time is 10 9 poise. At the point in time when the entire heating / pressing stroke is pressed, that is, at the end of the heating / pressing step, the lens material has a portion where the mold transfer surface is not completely transferred. After a predetermined time has elapsed after the completion of the heating and pressing step, the molding pressure is once reduced to zero, the pressing stage 15 is raised and separated from the upper die flange 11c. Immediately before the pressure is reduced to zero,
The spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surfaces, which have been under positive pressure, return to normal pressure.
次に再び加圧ステージ15を下降し、金型11のツバ部と
加圧ステージ15を密着させる。成形圧力を零にした時に
も、金型11の転写面11b及び金型12の転写面12bは、レン
ズ素材と接触したままである。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
程終了時点の空間11b,12bよりも、かなり小さい容積と
なっている。Next, the pressing stage 15 is lowered again, and the brim portion of the mold 11 and the pressing stage 15 are brought into close contact with each other. Even when the molding pressure is reduced to zero, the transfer surface 11b of the mold 11 and the transfer surface 12b of the mold 12 remain in contact with the lens material. At this time, the spaces 11b, 12b surrounded by the transfer surfaces 11a, 12a and the end surface of the lens material have a considerably smaller volume than the spaces 11b, 12b at the end of the heating and pressing step.
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。Next, a cooling and pressurizing step is started. During the cooling and pressurizing step, the molding pressure is temporarily reduced to zero after a predetermined time has elapsed, and the pressurizing stage 15 is raised to separate from the upper die flange 11c.
前記圧力を零にする直前、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。Immediately before the pressure is reduced to zero, the spaces 11b and 12b surrounded by the mold transfer surfaces 11a and 12a and the lens material end surfaces, which have been positive, return to normal pressure.
次に再び加圧ステージ15を下降し、金型ツバ部11c密
着させる。この時上型ツバ部11cと胴型14の端面は接触
したままである。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、冷却加圧工程開始直前の
空間11b,12bよりもかなり小さい容積となっているか、
あるいは殆どなくなっている。Next, the pressurizing stage 15 is lowered again to bring the mold flange 11c into close contact. At this time, the end surface of the upper die collar portion 11c and the end surface of the body die 14 remain in contact. At this time, the spaces 11b, 12b surrounded by the transfer surfaces 11a, 12a and the lens material end surface have a considerably smaller volume than the spaces 11b, 12b immediately before the start of the cooling and pressurizing step,
Or almost gone.
次に430℃迄冷却加圧を行う。まれにレンズ素材面
に、小さな凹部が冷却加圧工程中に成形圧力を抜いた後
にも残っている場合があるが、冷却加圧工程中のレンズ
素材の収縮による流動により、金型転写面11a,12aとレ
ンズ素材端面で囲まれる空間11b,12bは完全になくな
る。Next, cooling and pressurizing are performed to 430 ° C. In rare cases, small concave portions may remain on the lens material surface even after the molding pressure is released during the cooling and pressurizing process.However, due to the flow due to the contraction of the lens material during the cooling and pressurizing process, the mold transfer surface 11a , 12a and the spaces 11b, 12b surrounded by the lens material end faces are completely eliminated.
又、レンズ素材の線膨張率が50×10/℃以上であれ
ば、レンズ素材の収縮による流動が充分に得られるた
め、レンズ表面の凹部はなくなり易くなる。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。If the coefficient of linear expansion of the lens material is 50 × 10 / ° C. or more, sufficient flow due to shrinkage of the lens material can be obtained, so that the concave portion on the lens surface is easily eliminated. Thereafter, the pressure supply is stopped and the molding pressure is reduced to zero. 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, since the pressing stage and the upper die flange are not fixed, and the die and the material are always formed in close contact with each other, the transferability is greatly improved.
以上の実施例では、加熱加圧工程終了時点と冷却加圧
工程中に成形圧力を各々１回ずつ零にしたが、レンズ素
材の大きさによっては各々減圧するだけで、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、金型転写面11a,12aとレンズ素材で囲まれ
る空間11b,12は常圧に戻るので、減圧するだけでも良
い。In the above embodiment, the molding pressure was set to zero once each at the end of the heating / pressing step and during the cooling / pressing step.
Since the spaces 11b and 12b surrounded by the lens material end faces 11a and 12a return to normal pressure, the mold transfer surfaces 11a and 12a and the spaces 11b and 12 surrounded by the lens material return to normal pressure. .
第８図に示す成形型の転写面の半径Rmと上型と下型の
空間に供給されたレンズ素材の前記転写面に対向する面
の半径Rgの関係がRg＞Rmであるとき、成形金型転写面と
レンズ素材端面で囲まれた閉じた空間ができるため、本
実施例で行う成形方法をとれば、特に効果がある。ま
た、本実施例で使用した、第５図に示すような円柱状の
レンズ素材を成形する場合は特に有効である。又、レン
ズ厚を調整する胴型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等の各工程を、別ス
テージに移動して行う型移動方式を採用しても、全く同
じ性能のレンズを得ることができる。When the relationship between the radius Rm of the transfer surface of the molding die shown in FIG. 8 and the radius Rg of the surface of the lens material supplied to the space between the upper die and the lower die facing the transfer surface satisfies Rg> Rm, the molding metal Since there is a closed space surrounded by the mold transfer surface and the end surface of the lens material, the molding method of this embodiment is particularly effective. In addition, it is particularly effective when a cylindrical lens material as shown in FIG. 5 used in this embodiment is formed. The barrel mold 4 for adjusting the lens thickness does not need to be in contact with the upper and lower molds as shown in FIG.
A method of adjusting the distance between the pressing stage 15 and the forming stage 16 by providing a ring-shaped body or a block-shaped spacer outside the lower die flanges 11c and 12c in addition to the close contact with the lower die flange 11c and 12c may be used. Further, even if a mold moving method in which each step such as a cooling pressurizing step and a cooling step is moved to another stage is adopted, lenses having exactly the same performance can be obtained.
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。成形途中に於て、加
熱加圧工程終了時点と冷却加圧工程中で一旦圧力供給を
停止し、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。Effects of the Invention The present invention has the following effects because it is the molding method described above. In the middle of molding, the pressure supply is temporarily stopped at the end of the heating and pressurizing step and during the cooling and pressurizing step, the molding pressure is reduced to zero, and the pressure in the mold is returned to normal pressure, thereby generating the air generated conventionally. This eliminates molding defects due to entrainment, and allows molding of lenses with excellent shape accuracy and surface accuracy.
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成形が可能であるために、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。Further, since the upper and lower molds and the lens material can be formed in a state of being in close contact with each other until the end of the cooling step, the accuracy of the upper and lower molds can be directly transferred to the lens material. In addition, shaft misalignment can be prevented.
更に上下の金型とレンズ素材が冷却加圧工程終了時点
まで常に密着した状態で成形することが可能であるため
に、レンズの両面の傾きを成形ステージと加圧ステージ
或いは、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。Furthermore, since the upper and lower molds and the lens material can be molded in a state of being in close contact with each other until the end of the cooling and pressurizing step, the inclination of both surfaces of the lens is adjusted by a molding stage and a pressure stage, or a mold and a barrel mold. You can easily ensure by. Due to the close contact between the mold and the lens material, the temperature distribution of the heat transmitted from the mold to the lens material is uniform, and the shape is ensured because the deformation during the molding of the lens material and the shrinkage during cooling do not become uneven. An accurate lens can be obtained.
一方、成形圧力を零にするか減圧する際に、金型とレ
ンズ素材を離しても、冷却加圧工程で成形圧力を零にす
るか減圧することにより、所望のレンズ性能を得ること
ができる。レンズ素材の線膨張率が100℃〜300℃で50×
10/℃以上あれば、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ことがで
きる。On the other hand, when the molding pressure is reduced to zero or the pressure is reduced, even if the mold and the lens material are separated, the desired lens performance can be obtained by setting the molding pressure to zero or reducing the pressure in the cooling and pressurizing step. . 50x when the linear expansion coefficient of the lens material is 100 ° C to 300 ° C
When the temperature is 10 / ° C. or more, a slight deviation between the shape of the mold transfer surface and the shape of the lens material can be eliminated during cooling and pressing.
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
示した説明図、第４図〜第７図は従来の成形装置及びレ
ンズ素材の構造図、第８図は一般的な成形型とレンズ素
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 cross-sectional views of a molding apparatus for realizing the molding method of the present invention, FIG. 3 is an explanatory view showing a general molding profile, and FIGS. 4 to 7 are conventional molding profiles. FIG. 8 is a cross-sectional view of a general molding die and lens material. 11 …… Upper mold, 11a …… Mold transfer surface, 11b …… Space, 11c…
… Upper collar, 12c …… lower collar, 12 …… lower mold, 12a…
… Mold transfer surface, 12b …… space, 13 …… lens material, 14…
... Body type, 15 ... Pressure stage, 16 ... Molding stage.
Claims (4)
と下型の空間に供給されたレンズ素材を加圧成形する方
法であって、加熱加圧工程終了後に成形圧力を少なくと
も１回以上減圧するかあるいは零にし、冷却工程中に成
形圧力を少なくとも１回以上減圧するかあるいは零にす
ることを特徴とするレンズの成形方法。1. A method for press-molding a lens material supplied to a space between an upper mold and a lower mold in a molding die comprising an upper mold and a lower mold, wherein the molding pressure is reduced after the heating and pressurizing step. A method of molding a lens, wherein the pressure is reduced or reduced to at least one time or zero, and the molding pressure is reduced or reduced to at least one or more times during a cooling step.
間に供給されたレンズ素材の前記転写面に対向する面の
半径Rgの関係がRg＞Rmであ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 relationship between the radius Rm of the transfer surface of the molding die and the radius Rg of the surface of the lens material supplied to the space between the upper die and the lower die facing the transfer surface is Rg> Rm. Claim 1
A method for molding the lens according to the above.
する請求項１記載のレンズの成形方法。3. The method according to claim 1, wherein the lens material is a cylindrical glass material.
成形されることを特徴とする請求項１記載のレンズの成
形方法。4. The lens forming method according to claim 1, wherein the upper and lower molds and the lens material are always formed in a state of being in contact with each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1203317A JP2616029B2 (en) | 1989-08-04 | 1989-08-04 | Lens molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1203317A JP2616029B2 (en) | 1989-08-04 | 1989-08-04 | Lens molding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0369520A JPH0369520A (en) | 1991-03-25 |
| JP2616029B2 true JP2616029B2 (en) | 1997-06-04 |
Family
ID=16472022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1203317A Expired - Fee Related JP2616029B2 (en) | 1989-08-04 | 1989-08-04 | Lens molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2616029B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11278853A (en) * | 1998-03-31 | 1999-10-12 | Fuji Photo Optical Co Ltd | Method for forming optical parts |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60246231A (en) * | 1984-05-18 | 1985-12-05 | Hitachi Ltd | Press forming of lens |
| JPS6467312A (en) * | 1987-09-09 | 1989-03-14 | Olympus Optical Co | Forming method for optical element |
-
1989
- 1989-08-04 JP JP1203317A patent/JP2616029B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0369520A (en) | 1991-03-25 |
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