WO2011083692A1 - Glass preform and method of manufacture thereof - Google Patents

Glass preform and method of manufacture thereof Download PDF

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Publication number
WO2011083692A1
WO2011083692A1 PCT/JP2010/073180 JP2010073180W WO2011083692A1 WO 2011083692 A1 WO2011083692 A1 WO 2011083692A1 JP 2010073180 W JP2010073180 W JP 2010073180W WO 2011083692 A1 WO2011083692 A1 WO 2011083692A1
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Prior art keywords
glass
glass preform
mold
shape
lens
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PCT/JP2010/073180
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French (fr)
Japanese (ja)
Inventor
史雄 佐藤
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日本電気硝子株式会社
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Priority to CN2010800607226A priority Critical patent/CN102753491A/en
Publication of WO2011083692A1 publication Critical patent/WO2011083692A1/en

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    • 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
    • C03B2215/40—Product characteristics
    • C03B2215/46—Lenses, e.g. bi-convex
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Definitions

  • the present invention relates to a glass preform for producing optical glass such as a lens obtained by mold press molding and a method for producing the same.
  • a simple spherical or elliptical spherical glass preform is used to produce such a lens, it is difficult to obtain a desired shape with high accuracy because the amount of glass deformation caused by pressing increases. Therefore, a glass preform having a shape approximate to the final lens shape has been proposed for the purpose of reducing the amount of deformation of the glass.
  • a lens-approximate-shaped glass preform is produced by grinding and polishing glass cut out from a glass ingot, or a method of polishing after a simple press using a hand press has been adopted.
  • the direct press method which press-molds a high-temperature glass gob is mentioned (for example, refer patent document 1).
  • the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a glass preform having high volume accuracy, excellent surface quality, and low cost.
  • the present inventors have found that the above problems can be solved by a glass preform obtained by subjecting a glass lump to a specific process, and propose the present invention.
  • the present invention relates to a glass preform characterized in that it is made of a glass lump mold press and has an unpolished surface.
  • the glass preform of the present invention is manufactured by mold press molding using a mold, even when a complicated shape such as an aspheric surface is formed on the glass surface, the dimensional variation is small (excellent in volume accuracy). ). Furthermore, since the grinding and polishing steps after mold press molding can be omitted, the surface accuracy is high (for example, there are few linear grooves due to polishing or the like). Further, unlike the glass preform produced by the conventional direct press, the glass preform of the present invention does not have defects such as wrinkles and shear marks on the surface, and therefore has excellent surface quality. For this reason, the lens obtained by press molding the glass preform has almost no optical image disturbance.
  • the glass preform of the present invention is characterized in that it has any lens approximate shape selected from biconvex, biconcave, meniscus, plano-convex and plano-concave.
  • the glass preform has a shape that approximates the target lens shape
  • the amount of glass deformation during mold press molding can be reduced. Therefore, a lens having a desired shape can be obtained with high accuracy.
  • the glass preform of the present invention is characterized in that the optically effective surface is an aspherical shape.
  • the glass preform of the present invention is characterized in that the glass transition point of the glass block is 700 ° C. or lower.
  • the glass preform of the present invention is characterized in that a rough surface derived from a press mold is transferred to the surface of the glass preform.
  • the glass preform of the present invention is characterized in that a rough surface derived from a press mold is transferred to a portion other than the optically effective surface.
  • a rough surface is easily formed on the manufactured lens at a location other than the optically effective surface (for example, a side surface portion of the lens). Accordingly, it is preferable because the rough surface can diffuse light due to vignetting, and a black coating for preventing intrusion of external light applied to the side surface of the lens can be easily adhered.
  • the glass preform of the present invention is characterized in that the boundary portion between the optically effective surface and the side surface is a convex curved surface.
  • a glass preform for example, when an edge-shaped corner is formed at the boundary portion between the optically effective surface and the side surface portion, when an impact is applied from the outside, the stress applied to the corner portion increases and may be damaged. . Even minute breakage leads to deterioration of volumetric accuracy, or broken glass pieces become dust and cause deterioration of the quality of the glass preform.
  • angular part by a chamfering process is also considered, when the said method is employ
  • the glass preform of the present invention is characterized in that a compressive stress layer is formed on the surface.
  • the glass preform When a compressive stress layer is formed on the surface of the glass preform, the glass preform is strengthened due to the difference in compressive stress between the surface and the inside, so that damage during handling can be reduced.
  • the present invention relates to a lens obtained by mold-pressing any one of the above glass preforms.
  • the lens of the present invention is characterized in that a rough surface derived from a press die is transferred to a portion other than the optically effective surface.
  • the present invention includes molding molten glass to produce a glass lump having a predetermined shape, and mold pressing the glass lump using a mold having at least a concave portion or a convex portion.
  • the present invention relates to a method for manufacturing a glass preform.
  • the manufacturing method of the glass preform of this invention is characterized by including heating a glass lump so that it may become a viscosity of 10 ⁇ 9 > dPa * s or less before mold press molding.
  • the glass lump and the mold are heated at the same time, and the press molding is performed when the temperature rises to near the softening point of the glass lump. Heating and cooling are required, and press molding takes a long time.
  • the time required for press molding can be greatly shortened. .
  • the glass preform of the present invention is excellent in volumetric accuracy even when a complicated shape is formed on the glass surface, and has high surface accuracy because the grinding and polishing steps after mold press molding can be omitted. Therefore, it has a remarkable effect that the surface quality is excellent. For this reason, the lens obtained by press molding the glass preform has almost no optical image disturbance. Furthermore, since the glass preform of the present invention can omit the grinding and polishing steps after mold press molding, it also solves the cost and environmental problems caused by the waste glass.
  • (A) is a biconvex shape
  • (b) is a biconcave shape
  • (c) is a meniscus shape
  • (d) is a plano-convex shape
  • (e) is a plano-concave glass preform.
  • the glass preform of the present invention is obtained by mold press molding a glass lump and is not polished after the mold press molding.
  • the shape of the glass block is not particularly limited, but an elliptical shape or a substantially spherical shape is preferable because a glass preform having a desired shape can be easily obtained.
  • the shape of the glass preform of the present invention is not particularly limited, but is preferably any lens approximate shape selected from biconvex, biconcave, meniscus, planoconvex and planoconcave. What is necessary is just to select the shape of a glass preform suitably according to the lens shape made into the objective.
  • FIG. 1 shows an embodiment of the glass preform of the present invention.
  • A) of FIG. 1 is a diagram showing a bi-concave shape,
  • (b) is a biconcave shape,
  • (c) is a meniscus shape,
  • (d) is a plano-convex shape, and
  • (e) is a plano-concave glass preform. .
  • a rough surface derived from a press die is formed at a location other than the optically effective surface (for example, a side surface portion of the lens). It is preferable.
  • a rough surface derived from a press die may be formed at a place other than the optically effective surface, and thereby a lens having a desired rough surface can be easily produced. It becomes possible.
  • the rough surface formed here is formed by dot-like or linear protrusions because the rough surface formed by polishing or the like formed on the mold surface is transferred to the glass surface during mold press molding.
  • the rough surface of the glass preform is formed by polishing, concave points or lines are formed.
  • a rough surface may be formed on the side surface portion S. Note that the side surface portion S may have a curved surface shape.
  • the optically effective surface of the glass preform is preferably aspheric.
  • the aspherical shape include those having a vertical cross-sectional shape that is a quadratic curve.
  • k is the conic coefficient that determines the shape of the quadratic curve
  • c is the central curvature (R is the central curvature radius).
  • the conic coefficient k satisfies the range of ⁇ 1 ⁇ k ⁇ 0, particularly ⁇ 1 ⁇ k ⁇ 0.7, so that the shape is a spheroid
  • the surface is aspherical.
  • the glass transition point of the glass block is preferably 700 ° C. or lower, 650 ° C. or lower, 640 ° C. or lower, particularly 630 ° C. or lower, from the viewpoint of easy mold press molding.
  • the boundary portion B between the optically effective surface L and the side surface portion S of the glass preform is preferably a convex curved surface.
  • the radius of curvature of the convex curved surface is preferably 10 ⁇ m or more, 100 ⁇ m or more, 500 ⁇ m or more, and particularly preferably 1 mm or more. If the radius of curvature of the convex curved surface is too small, when an impact is applied from the outside, the stress applied to the boundary portion B is increased and may be damaged.
  • the boundary portion B can be formed in a convex curved surface shape, for example, depending on the shape of a mold at the time of mold press molding of a glass preform.
  • a compression stress layer is formed on the surface of the glass preform.
  • the compressive stress in the compressive stress layer is preferably 0.1 MPa or more, 1 MPa or more, 10 MPa or more, particularly 40 MPa or more. If the compressive stress is too small, it tends to break during handling.
  • the material of the glass block is not particularly limited.
  • to glass refers to a glass containing a corresponding component as an essential component.
  • the glass preform of the present invention may have a rough surface, that is, a dot-like or linear protrusion on the surface. This is the result of polishing scratches and the like formed on the mold surface being transferred to the glass surface during mold press molding, and can be said to be a feature of a glass preform manufactured by mold press molding.
  • the line shape has a line width of 0.001 to 10 ⁇ m and the height of the protrusion is 0.001 to 5 ⁇ m. In the case of dot-like ones, the diameter is 0.001 to 10 ⁇ m and the height is 0.001 to 5 ⁇ m.
  • the protrusions present on the optically effective surface are preferably smaller, and the line width and diameter thereof are 2 ⁇ m or less, more preferably 1 ⁇ m or less, and more preferably 0.5 ⁇ m or less.
  • the rough surface derived from the press mold is preferably transferred to a surface other than the optically effective surface of the glass preform.
  • a glass material prepared to have a desired composition is melted to obtain a molten glass.
  • molten glass is formed into an ingot to obtain a glass material.
  • the obtained glass material is cut and polished to produce a glass lump having a predetermined shape (for example, a substantially spherical shape).
  • the glass lump Prior to mold press molding, it is preferable to preheat the glass lump using an electric furnace or the like.
  • the glass lump is heated at a temperature at which the viscosity of the glass is 10 9 dPa ⁇ s or less, 10 7.6 dPa ⁇ s or less, 10 6.5 dPa ⁇ s or less, particularly 10 5.4 dPa ⁇ s or less. Is preferred. If the viscosity of the glass is too high, the time required for mold press molding tends to increase. On the other hand, when the viscosity of the glass is too low, the glass preform becomes high temperature, and the mold becomes high temperature at the same time, and the deterioration easily proceeds.
  • the heated glass lump is filled into a mold having at least a concave portion or a convex portion heated to the vicinity of the softening point of the glass, and pressure is applied until a desired shape is formed to perform mold press molding.
  • the atmosphere during mold press molding is preferably vacuum or non-oxidizing in order to prevent deterioration of the mold due to oxidation.
  • the non-oxidizing gas include a reducing gas such as hydrogen, or an inert gas such as nitrogen and argon. Among these, it is preferable to use nitrogen because it is relatively easy to handle and inexpensive.
  • the glass lump may be formed by dropping molten glass onto an inverted conical mold and cooling it into a substantially spherical shape such as a sphere or an elliptical sphere. At this time, after cooling the drop-formed glass once to room temperature, it is heated again to a temperature at which the viscosity of the glass becomes 10 9 dPa ⁇ s or less and used for a mold press. Then, when the viscosity of the glass reaches a temperature of 10 9 dPa ⁇ s or less, it can be transferred to a mold and used for mold press molding.
  • a lens can be obtained by performing mold press molding using the glass preform of the present invention.
  • the mold press molding method is not specifically limited here, The method similar to the above-mentioned mold press molding used with the manufacturing method of a glass preform is mentioned.
  • SUS As the material of the press die, SUS, carbide or other hard metal, Co, carbon or the like can be used.
  • a release film it is possible to use a noble metal type such as Pt, a carbon type such as DLC, or a nitride type release film.
  • Example 1 Glass raw materials were prepared so as to have a SiO 2 —B 2 O 3 -based composition, and were melted at 1300 ° C. for 2 hours using a platinum crucible. After melting, the glass melt was shaped into an ingot and annealed. It was 500 degreeC when the glass transition point was measured about the obtained ingot.
  • the ingot was cut and polished to a desired size to produce a spherical glass lump having a mirror surface.
  • the mold was filled and pressure was applied until a desired shape was formed in a nitrogen atmosphere, and mold press molding was performed. After mold press molding, it was gradually cooled to room temperature to obtain a meniscus glass preform as shown in FIG.
  • the shape and dimensions of the produced glass preform were as follows.
  • the volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ⁇ 0.1%.
  • the compressive stress in the compressive stress layer on the glass preform surface was 48 MPa.
  • the compression stress was measured by the photoelastic method.
  • the surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform.
  • the line width was 0.5 ⁇ m and the height was 0.1 ⁇ m. Since the mold surface contacting the side surface was a mirror surface, the side surface portion of the obtained glass preform was also a mirror surface.
  • mold press molding was performed in the same manner as described above to obtain a meniscus lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens also became a mirror surface.
  • Example 2 A glass raw material was prepared and melted so as to have a SiO 2 —B 2 O 3 -based composition, and the glass melt was dropped onto an inverted conical mold from a nozzle and formed into an elliptical sphere shape while cooling.
  • the obtained oval spherical glass lump was heated in an electric furnace to a temperature where the viscosity was 10 4.8 dPa ⁇ s, and the glass was heated to a temperature where the viscosity was 10 8.6 dPa ⁇ s.
  • a mold in which a convex shape was formed was filled, and pressure was applied until the shape was formed in a nitrogen atmosphere, and mold press molding was performed. After mold press molding, it was gradually cooled to room temperature to obtain a biconvex glass preform as shown in FIG. There were no defects such as insufficient filling or cracking at the time of mold pressing, or fusion between the glass and the mold.
  • the shape and dimensions of the produced glass preform were as follows.
  • the volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ⁇ 1%.
  • the compressive stress in the compressive stress layer on the surface of the glass preform was 12 MPa.
  • the surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform.
  • the line width was 0.1 ⁇ m and the height was 0.05 ⁇ m. Since the mold surface in contact with the side surface was rough, the side surface portion of the obtained glass preform was also rough.
  • the linear trace forming the rough surface was formed by transferring the mold surface by pressing, and had a convex shape.
  • mold press molding was performed in the same manner as described above to obtain a biconvex lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens was also rough.
  • Example 3 Using the glass lump obtained in Example 1, press molding was performed under the same conditions as in Example 1 except that the glass lump was heated in the electric furnace to near the temperature at which the viscosity of the glass became 10 4.6 dPa ⁇ s. And a glass preform was produced. At this time, a mold was used in which a portion corresponding to the optically effective surface was processed into an aspheric shape so that an aspheric shape was formed on the surface.
  • the shape and dimensions of the produced glass preform were as follows.
  • the volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ⁇ 1%.
  • the surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform.
  • the line width was 0.1 ⁇ m and the height was 0.05 ⁇ m. Since the mold surface in contact with the side surface of the glass preform was rough, the side surface portion of the obtained glass preform was also rough.
  • the linear trace forming the rough surface was formed by transferring the mold surface by pressing, and had a convex shape.
  • mold press molding was performed in the same manner as described above to obtain an aspheric meniscus lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens was also rough.
  • the present invention even when a complicated shape is formed on the glass surface, a glass preform having excellent volume accuracy, high surface accuracy, and no defects such as wrinkles and shear marks is obtained. Is possible. Moreover, in the manufacturing process of the glass preform of the present invention, since the grinding and polishing steps after mold press molding can be omitted, the cost and environmental problems due to the waste glass can be solved. Furthermore, it is possible to obtain a lens with almost no optical image disturbance by press-molding the glass preform of the present invention.

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
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Abstract

Disclosed is a glass preform which has high volume accuracy and excellent surface quality and is low cost. Specifically disclosed are: a glass preform formed from a press-molded glass mass and having an unpolished surface; and a glass preform manufacturing method which comprises molding molten glass into a glass mass having a predetermined configuration and press-molding the glass mass by use of a mold having at least a concave portion or a convex portion.

Description

ガラスプリフォームおよびその製造方法Glass preform and method for producing the same
　本発明はモールドプレス成形により得られるレンズ等の光学ガラスを製造するためのガラスプリフォームおよびその製造方法に関する。 The present invention relates to a glass preform for producing optical glass such as a lens obtained by mold press molding and a method for producing the same.
　近年、デジタルカメラの用途拡大および高機能化に伴い、使用されるレンズの形状も多様化しており、従来にも増して様々な形状のレンズの非球面化の要望が増えている。また、光ピックアップに使用される凸形状レンズについても、曲率半径の小さい急峻な形状が要求されている。 In recent years, with the expansion of applications and higher functionality of digital cameras, the shapes of lenses used have also diversified, and there is an increasing demand for aspherical lenses with various shapes. Also, a convex lens used for an optical pickup is required to have a steep shape with a small curvature radius.
　このようなレンズを作製するために、単なる球形状や楕円球形状のガラスプリフォームを使用すると、プレスによるガラスの変形量が大きくなるため、所望の形状を精度良く得ることが困難であった。そのため、ガラスの変形量を小さくする目的で、最終レンズ形状に近似した形状を有するガラスプリフォームが提案されている。従来、そのようなレンズ近似形状ガラスプリフォームは、ガラスインゴットから切り出したガラスを研削、研磨することによって作製するか、あるいはハンドプレスによる簡易プレスの後に研磨加工する方法が採られている。その他、高温のガラスゴブをプレス成型するダイレクトプレス法が挙げられる（例えば、特許文献１参照）。 When a simple spherical or elliptical spherical glass preform is used to produce such a lens, it is difficult to obtain a desired shape with high accuracy because the amount of glass deformation caused by pressing increases. Therefore, a glass preform having a shape approximate to the final lens shape has been proposed for the purpose of reducing the amount of deformation of the glass. Conventionally, such a lens-approximate-shaped glass preform is produced by grinding and polishing glass cut out from a glass ingot, or a method of polishing after a simple press using a hand press has been adopted. In addition, the direct press method which press-molds a high-temperature glass gob is mentioned (for example, refer patent document 1).
日本国特公平７－２９７８１号公報Japanese Patent Publication No. 7-29781
　ガラスプリフォームを製造するに当たっては、目的とするレンズの厚さ、径、曲率など、いくつもの部位の寸法を精度良く作製する必要がある。研削、研磨によって複雑な形状のガラスプリフォームを作製する場合、寸法にバラツキが生じやすく、ガラスプリフォームとして最も重要な特性である体積精度が変動してしまうという問題が生じる。また、研磨で作製した場合、側面に研削面が残ってしまい、そこからガラス粉などの粉塵が発生して、レンズの鏡面品質に影響を与える懸念も持っている。またプレスした際に、その研削面がレンズ有効面に及んでしまった場合、不良となってしまう問題もある。また、当該方法は工程が煩雑であると同時に、研削、研磨による廃棄ガラスが増加するため、コストや環境面において問題がある。 In manufacturing a glass preform, it is necessary to accurately produce dimensions of several parts such as the thickness, diameter, and curvature of a target lens. When a glass preform having a complicated shape is produced by grinding or polishing, there is a problem that the size is likely to vary, and the volume accuracy, which is the most important characteristic of the glass preform, varies. Moreover, when it produces by grinding | polishing, a grinding surface will remain on a side surface, and dusts, such as glass powder, will generate | occur | produce from there, and there also exists a concern which affects the mirror surface quality of a lens. In addition, when the ground surface reaches the lens effective surface when pressed, there is a problem that it becomes defective. In addition, the method has complicated processes, and at the same time, waste glass due to grinding and polishing is increased, which causes problems in cost and environment.
　ハンドプレスによりガラスプリフォームを作製する場合、プレス金型に離型剤を塗布する必要がある。離型剤はガラスに付着しやすく、プレス後に離型剤を除去するために研磨が必要となる。この場合も、既述の研削、研磨による方法と同様の問題が生じてしまう。 When producing glass preforms by hand press, it is necessary to apply a release agent to the press mold. The release agent is likely to adhere to the glass, and polishing is necessary to remove the release agent after pressing. Also in this case, the same problem as the above-described grinding and polishing method occurs.
　ダイレクトプレスによる製造方法では、高温のガラスゴブが低温の金型と接触するため、ガラスゴブのうち金型に接触する部分だけが急冷されて変形不十分となり、表面にシワが発生しやすくなる。また、ガラスゴブを金型に供給する際のガラスゴブ切断時にシャーマークが発生してしまうため、当該シャーマークをプレス後に研磨により除去する必要があるという問題がある。 In the manufacturing method using the direct press, since the high-temperature glass gob comes into contact with the low-temperature mold, only the portion of the glass gob that contacts the mold is rapidly cooled, resulting in insufficient deformation, and wrinkles are likely to occur on the surface. Further, since a shear mark is generated when the glass gob is cut when supplying the glass gob to the mold, there is a problem that the shear mark needs to be removed by polishing after pressing.
　本発明は、以上のような課題を解決するためになされたものであり、高い体積精度を有し、表面品位に優れ、さらに低コストであるガラスプリフォームを提供することを目的とする。 The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a glass preform having high volume accuracy, excellent surface quality, and low cost.
　本発明者等は鋭意検討した結果、ガラス塊に対し特定の工程を施したガラスプリフォームにより、前記課題を解決できることを見出し、本発明として提案するものである。 As a result of intensive studies, the present inventors have found that the above problems can be solved by a glass preform obtained by subjecting a glass lump to a specific process, and propose the present invention.
　すなわち、本発明は、ガラス塊のモールドプレス成形体からなり、かつ、表面が未研磨であることを特徴とするガラスプリフォームに関する。 That is, the present invention relates to a glass preform characterized in that it is made of a glass lump mold press and has an unpolished surface.
　本発明のガラスプリフォームは、金型を用いたモールドプレス成形により製造されるため、例えば非球面等の複雑な形状をガラス表面に形成する場合であっても寸法バラつきが小さい（体積精度に優れる）。さらに、モールドプレス成形後の研削および研磨工程を省略できるため表面精度が高い（例えば、研磨等による線状溝が少ない）。また、本発明のガラスプリフォームは、従来のダイレクトプレスにより作製したものと異なり、表面のシワやシャーマーク等の不具合を有しないため、表面品位に優れる。そのため、当該ガラスプリフォームをプレス成形して得られるレンズは、光学的な像の乱れの発生がほとんどない。 Since the glass preform of the present invention is manufactured by mold press molding using a mold, even when a complicated shape such as an aspheric surface is formed on the glass surface, the dimensional variation is small (excellent in volume accuracy). ). Furthermore, since the grinding and polishing steps after mold press molding can be omitted, the surface accuracy is high (for example, there are few linear grooves due to polishing or the like). Further, unlike the glass preform produced by the conventional direct press, the glass preform of the present invention does not have defects such as wrinkles and shear marks on the surface, and therefore has excellent surface quality. For this reason, the lens obtained by press molding the glass preform has almost no optical image disturbance.
　また、研削または研磨面から発生するガラス粉等のダストの問題がないため、当該ダストに起因する生産不良をなくすことが可能となる。 Also, since there is no problem of dust such as glass powder generated from the ground or polished surface, it becomes possible to eliminate production defects caused by the dust.
　第二に、本発明のガラスプリフォームは、両凸、両凹、メニスカス、平凸および平凹から選択されるいずれかのレンズ近似形状を有することを特徴とする。 Second, the glass preform of the present invention is characterized in that it has any lens approximate shape selected from biconvex, biconcave, meniscus, plano-convex and plano-concave.
　このように、ガラスプリフォームが目的とするレンズ形状に近似する形状を有することにより、モールドプレス成形時のガラス変形量を低減することができる。したがって、所望の形状を有するレンズを精度良く得ることが可能となる。 Thus, when the glass preform has a shape that approximates the target lens shape, the amount of glass deformation during mold press molding can be reduced. Therefore, a lens having a desired shape can be obtained with high accuracy.
　第三に、本発明のガラスプリフォームは、光学有効面が非球面形状であることを特徴とする。 Third, the glass preform of the present invention is characterized in that the optically effective surface is an aspherical shape.
　光学有効面が非球面形状のガラスプリフォームを用いれば、非球面レンズを作製する場合、プレス成形時のガラスの変形量が小さくて済むため、プレス成形時間の短縮および寸法精度の向上に繋がるという利点がある。 If a glass preform with an aspherical optical effective surface is used, when producing an aspheric lens, the amount of deformation of the glass during press molding can be reduced, leading to a reduction in press molding time and an improvement in dimensional accuracy. There are advantages.
　第四に、本発明のガラスプリフォームは、ガラス塊のガラス転移点が７００℃以下であることを特徴とする。 Fourth, the glass preform of the present invention is characterized in that the glass transition point of the glass block is 700 ° C. or lower.
　７００℃以下という比較的低いガラス転移点を有するガラス塊を用いることにより、モールドプレス成形が容易となり、本発明のガラスプリフォームが得られやすくなる。 By using a glass lump having a relatively low glass transition point of 700 ° C. or lower, mold press molding is facilitated, and the glass preform of the present invention is easily obtained.
　第五に、本発明のガラスプリフォームは、ガラスプリフォーム表面にプレス金型由来の粗面が転写されていることを特徴とする。 Fifth, the glass preform of the present invention is characterized in that a rough surface derived from a press mold is transferred to the surface of the glass preform.
　第六に、本発明のガラスプリフォームは、光学有効面以外の箇所にプレス金型由来の粗面が転写されていることを特徴とする。 Sixth, the glass preform of the present invention is characterized in that a rough surface derived from a press mold is transferred to a portion other than the optically effective surface.
　当該構成のガラスプリフォームを用いてモールドプレス成形を行うことにより、作製されたレンズにも、光学有効面以外の箇所（例えば、レンズの側面部）に粗面が形成されやすくなる。これにより、当該粗面によりケラレによる光を拡散することが可能になったり、レンズ側面に塗布する外部光の侵入防止用の黒色塗装が接着しやすくなるため好ましい。 By performing mold press molding using the glass preform having the above configuration, a rough surface is easily formed on the manufactured lens at a location other than the optically effective surface (for example, a side surface portion of the lens). Accordingly, it is preferable because the rough surface can diffuse light due to vignetting, and a black coating for preventing intrusion of external light applied to the side surface of the lens can be easily adhered.
　第七に、本発明のガラスプリフォームは、光学有効面と側面部との境界部分が凸曲面状であることを特徴とする。 Seventh, the glass preform of the present invention is characterized in that the boundary portion between the optically effective surface and the side surface is a convex curved surface.
　ガラスプリフォームにおいて、光学有効面と側面部との境界部分に例えばエッジ状角部が形成されると、外部から衝撃が加わった際に当該角部にかかる応力が大きくなり、破損するおそれがある。微小な破損でも体積精度の悪化に繋がったり、破損したガラス片が粉塵となってガラスプリフォームの品質悪化の原因となる。なお、面取り加工により角部を取り除く方法も考えられるが、当該方法を採用した場合、工程数が増えるため生産効率やコストが上昇してしまう。また、ガラスプリフォームの体積精度の低下に繋がる。 In a glass preform, for example, when an edge-shaped corner is formed at the boundary portion between the optically effective surface and the side surface portion, when an impact is applied from the outside, the stress applied to the corner portion increases and may be damaged. . Even minute breakage leads to deterioration of volumetric accuracy, or broken glass pieces become dust and cause deterioration of the quality of the glass preform. In addition, although the method of removing a corner | angular part by a chamfering process is also considered, when the said method is employ | adopted, since the number of processes will increase, production efficiency and cost will rise. Moreover, it leads to the fall of the volume accuracy of a glass preform.
　第八に、本発明のガラスプリフォームは、表面に圧縮応力層が形成されていることを特徴とする。 Eighth, the glass preform of the present invention is characterized in that a compressive stress layer is formed on the surface.
　ガラスプリフォームの表面に圧縮応力層が形成されていると、表面と内部との圧縮応力差によりガラスプリフォームが強化されるため、取扱い時の破損を低減することができる。 When a compressive stress layer is formed on the surface of the glass preform, the glass preform is strengthened due to the difference in compressive stress between the surface and the inside, so that damage during handling can be reduced.
　第九に、本発明は、前記いずれかのガラスプリフォームをモールドプレス成形してなることを特徴とするレンズに関する。 Ninth, the present invention relates to a lens obtained by mold-pressing any one of the above glass preforms.
　第十に、本発明のレンズは、光学有効面以外の箇所にプレス金型由来の粗面が転写されていることを特徴とする。 Tenth, the lens of the present invention is characterized in that a rough surface derived from a press die is transferred to a portion other than the optically effective surface.
　第十一に、本発明は、溶融ガラスを成形して所定形状のガラス塊を製造すること、および少なくとも凹部または凸部を有する金型を用いて当該ガラス塊をモールドプレス成形することを含むことを特徴とするガラスプリフォームの製造方法に関する。 Eleventhly, the present invention includes molding molten glass to produce a glass lump having a predetermined shape, and mold pressing the glass lump using a mold having at least a concave portion or a convex portion. The present invention relates to a method for manufacturing a glass preform.
　第十二に、本発明のガラスプリフォームの製造方法は、モールドプレス成形する前に、ガラス塊を１０９ｄＰａ・ｓ以下の粘度となるように加熱することを含むことを特徴とする。 12thly, the manufacturing method of the glass preform of this invention is characterized by including heating a glass lump so that it may become a viscosity of 10 < 9 > dPa * s or less before mold press molding.
　冷間で金型にガラス塊をセットし、ガラス塊と金型を同時に加熱し、ガラス塊の軟化点付近まで温度が上昇したところでプレス成形を行うと、プレス成形毎にガラス塊と金型の加熱と冷却が必要となり、プレス成形に長時間を要する。一方、本発明のガラスプリフォームの製造方法では、モールドプレス成形する前に、予めガラス塊を所定の粘度となるように加熱するため、プレス成形に要する時間を大幅に短縮することが可能となる。 When the glass lump is set in the mold in the cold, the glass lump and the mold are heated at the same time, and the press molding is performed when the temperature rises to near the softening point of the glass lump. Heating and cooling are required, and press molding takes a long time. On the other hand, in the method for producing a glass preform of the present invention, since the glass lump is heated in advance to have a predetermined viscosity before mold press molding, the time required for press molding can be greatly shortened. .
　本発明のガラスプリフォームは、複雑な形状をガラス表面に形成する場合であっても体積精度に優れ、モールドプレス成形後の研削および研磨工程を省略できるため表面精度が高く、またシワやシャーマーク等の不具合がないため表面品位に優れるという、顕著な効果を奏するものである。そのため、当該ガラスプリフォームをプレス成形して得られるレンズは、光学的な像の乱れの発生がほとんどない。さらに、本発明のガラスプリフォームは、モールドプレス成形後の研削および研磨工程を省略できるため、廃棄ガラスによるコストや環境面の問題も解決するものである。 The glass preform of the present invention is excellent in volumetric accuracy even when a complicated shape is formed on the glass surface, and has high surface accuracy because the grinding and polishing steps after mold press molding can be omitted. Therefore, it has a remarkable effect that the surface quality is excellent. For this reason, the lens obtained by press molding the glass preform has almost no optical image disturbance. Furthermore, since the glass preform of the present invention can omit the grinding and polishing steps after mold press molding, it also solves the cost and environmental problems caused by the waste glass.
本発明のガラスプリフォームの実施の形態を示す側面図である。（ａ）は両凸形状、（ｂ）は両凹形状、（ｃ）はメニスカス形状、（ｄ）は平凸形状、（ｅ）は平凹形状のガラスプリフォームを示す。It is a side view which shows embodiment of the glass preform of this invention. (A) is a biconvex shape, (b) is a biconcave shape, (c) is a meniscus shape, (d) is a plano-convex shape, and (e) is a plano-concave glass preform.
　本発明のガラスプリフォームは、ガラス塊をモールドプレス成形してなるものであり、かつモールドプレス成形後に研磨処理されていないことを特徴とする。ガラス塊の形状は特に限定されないが、楕円形状、略球状であると所望の形状を有するガラスプリフォームが得られやすいため好ましい。 The glass preform of the present invention is obtained by mold press molding a glass lump and is not polished after the mold press molding. The shape of the glass block is not particularly limited, but an elliptical shape or a substantially spherical shape is preferable because a glass preform having a desired shape can be easily obtained.
　本発明のガラスプリフォームの形状は特に限定されないが、両凸、両凹、メニスカス、平凸および平凹から選択されるいずれかのレンズ近似形状であることが好ましい。目的とするレンズ形状に応じて、適宜ガラスプリフォームの形状を選択すればよい。 The shape of the glass preform of the present invention is not particularly limited, but is preferably any lens approximate shape selected from biconvex, biconcave, meniscus, planoconvex and planoconcave. What is necessary is just to select the shape of a glass preform suitably according to the lens shape made into the objective.
　図１に本発明のガラスプリフォームの実施の形態を示す。図１の（ａ）は両凸形状、（ｂ）は両凹形状、（ｃ）はメニスカス形状、（ｄ）は平凸形状、（ｅ）は平凹形状のガラスプリフォームを示す図である。 FIG. 1 shows an embodiment of the glass preform of the present invention. (A) of FIG. 1 is a diagram showing a bi-concave shape, (b) is a biconcave shape, (c) is a meniscus shape, (d) is a plano-convex shape, and (e) is a plano-concave glass preform. .
　なお、既述のように、本発明のガラスプリフォームをモールド成形してなるレンズは、光学有効面以外の箇所（例えば、レンズの側面部）にプレス金型由来の粗面が形成されていることが好ましい。ここで、ガラスプリフォームにおいても、光学有効面以外の箇所にプレス金型由来の粗面が形成されていてもよく、それにより、所望の粗面が形成されたレンズを容易に作製することが可能となる。ここで形成される粗面は、金型表面に形成された研磨等による粗面がモールドプレス成形時にガラス表面に転写されてできるものであることから、点状あるいは線状の突起部により形成される。一方、ガラスプリフォームの粗面を研磨により形成した場合は、凹状の点あるいは線が形成されることになる。例えば、図１の各ガラスプリフォーム１において、側面部Ｓに粗面が形成されていてもよい。なお、側面部Ｓは曲面形状であってもよい。 As described above, in the lens formed by molding the glass preform of the present invention, a rough surface derived from a press die is formed at a location other than the optically effective surface (for example, a side surface portion of the lens). It is preferable. Here, also in the glass preform, a rough surface derived from a press die may be formed at a place other than the optically effective surface, and thereby a lens having a desired rough surface can be easily produced. It becomes possible. The rough surface formed here is formed by dot-like or linear protrusions because the rough surface formed by polishing or the like formed on the mold surface is transferred to the glass surface during mold press molding. The On the other hand, when the rough surface of the glass preform is formed by polishing, concave points or lines are formed. For example, in each glass preform 1 of FIG. 1, a rough surface may be formed on the side surface portion S. Note that the side surface portion S may have a curved surface shape.
　ガラスプリフォームの光学有効面は非球面形状であることが好ましい。非球面形状としては、例えば、縦断面形状が２次曲線であるものが挙げられる。具体的には、光学有効面部分の光軸を３軸直交ＸＹＺ座標系のＺ軸と一致させたときに、一般に下記式（１）にて表される形状が挙げられる。ここで、ｋは２次曲線の形状を決めるコーニック係数、ｃは中心曲率（Ｒは中心曲率半径）である。 The optically effective surface of the glass preform is preferably aspheric. Examples of the aspherical shape include those having a vertical cross-sectional shape that is a quadratic curve. Specifically, when the optical axis of the optically effective surface portion is made coincident with the Z axis of the three-axis orthogonal XYZ coordinate system, a shape generally expressed by the following formula (1) can be given. Here, k is the conic coefficient that determines the shape of the quadratic curve, and c is the central curvature (R is the central curvature radius).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　光学有効面が式（１）によって表されるガラスプリフォームにおいて、コーニック係数ｋが、－１＜ｋ＜０、特に－１＜ｋ＜－０．７の範囲を満たすことにより、形状が回転楕円面の非球面形状となる。 In the glass preform in which the optically effective surface is represented by the formula (1), the conic coefficient k satisfies the range of −1 <k <0, particularly −1 <k <−0.7, so that the shape is a spheroid The surface is aspherical.
　ガラス塊のガラス転移点は、モールドプレス成形を容易に行う観点から、７００℃以下、６５０℃以下、６４０℃以下、特に６３０℃以下であることが好ましい。 The glass transition point of the glass block is preferably 700 ° C. or lower, 650 ° C. or lower, 640 ° C. or lower, particularly 630 ° C. or lower, from the viewpoint of easy mold press molding.
　ガラスプリフォームの光学有効面Ｌと側面部Ｓとの境界部分Ｂが凸曲面状であることが好ましい。凸曲面の曲率半径は１０μｍ以上、１００μｍ以上、５００μｍ以上、特に１ｍｍ以上であることが好ましい。凸曲面の曲率半径が小さすぎると、外部から衝撃が加わった際に、境界部分Ｂにかかる応力が大きくなり、破損するおそれがある。境界部分Bは、例えば、ガラスプリフォームのモールドプレス成形時の金型の形状により、凸曲面状とすることができる。 The boundary portion B between the optically effective surface L and the side surface portion S of the glass preform is preferably a convex curved surface. The radius of curvature of the convex curved surface is preferably 10 μm or more, 100 μm or more, 500 μm or more, and particularly preferably 1 mm or more. If the radius of curvature of the convex curved surface is too small, when an impact is applied from the outside, the stress applied to the boundary portion B is increased and may be damaged. The boundary portion B can be formed in a convex curved surface shape, for example, depending on the shape of a mold at the time of mold press molding of a glass preform.
　ガラスプリフォームの表面に圧縮応力層が形成されていることが好ましい。圧縮応力層における圧縮応力は０．１ＭＰａ以上、１ＭＰａ以上、１０ＭＰａ以上、特に４０ＭＰａ以上であることが好ましい。圧縮応力が小さすぎると、取扱い時に破損しやすくなる。 It is preferable that a compression stress layer is formed on the surface of the glass preform. The compressive stress in the compressive stress layer is preferably 0.1 MPa or more, 1 MPa or more, 10 MPa or more, particularly 40 MPa or more. If the compressive stress is too small, it tends to break during handling.
　ガラス塊の材質は特に限定されず、例えば、ＳｉＯ２－Ｂ２Ｏ３系ガラス、Ｂ２Ｏ３－ＺｎＯ－Ｌａ２Ｏ３系ガラス、ＴｅＯ２－Ｂ２Ｏ３－ＷＯ３－Ｌａ２Ｏ３系ガラスなどがあげられる。なお「～系ガラス」とは、該当する成分を必須成分として含有するガラスをいう。 The material of the glass block is not particularly limited. For example, SiO 2 —B 2 O 3 glass, B 2 O 3 —ZnO—La 2 O 3 glass, TeO 2 —B 2 O 3 —WO 3 —La 2 O Examples thereof include 3 glass. Note that “to glass” refers to a glass containing a corresponding component as an essential component.
　ところで、本発明のガラスプリフォームは、表面に粗面、すなわち点状あるいは線状突起部が形成されている場合がある。これは、金型表面に形成された研磨傷等がモールドプレス成形時にガラス表面に転写されてできたものであり、モールドプレス成形により製造されたガラスプリフォームの特徴と言える。突起部の形状は、線状のものでは０．００１～１０μｍの線幅で突起の高さは０．００１～５μｍである。点状のものでは直径が０．００１～１０μｍ、高さは０．００１～５μｍである。光学有効面に存在する突起部は小さい方が好ましく、その線幅および直径は２μｍ以下、さらに１μｍ以下が好ましく、０．５μｍ以下になるとより好ましい。プレス金型由来の粗面は、ガラスプリフォームの光学有効面以外に転写されているのが好ましい。 Incidentally, the glass preform of the present invention may have a rough surface, that is, a dot-like or linear protrusion on the surface. This is the result of polishing scratches and the like formed on the mold surface being transferred to the glass surface during mold press molding, and can be said to be a feature of a glass preform manufactured by mold press molding. As for the shape of the protrusion, the line shape has a line width of 0.001 to 10 μm and the height of the protrusion is 0.001 to 5 μm. In the case of dot-like ones, the diameter is 0.001 to 10 μm and the height is 0.001 to 5 μm. The protrusions present on the optically effective surface are preferably smaller, and the line width and diameter thereof are 2 μm or less, more preferably 1 μm or less, and more preferably 0.5 μm or less. The rough surface derived from the press mold is preferably transferred to a surface other than the optically effective surface of the glass preform.
　次に本発明のガラスプリフォームの製造方法について説明する。 Next, a method for producing the glass preform of the present invention will be described.
　まず、所望の組成を有するように調合したガラス原料を溶融し、溶融ガラスとする。次に、溶融ガラスをインゴットに成形して硝材を得る。さらに、得られた硝材を切断、研磨して所定形状（例えば、略球状）のガラス塊を作製する。 First, a glass material prepared to have a desired composition is melted to obtain a molten glass. Next, molten glass is formed into an ingot to obtain a glass material. Further, the obtained glass material is cut and polished to produce a glass lump having a predetermined shape (for example, a substantially spherical shape).
　モールドプレス成形する前に、電気炉等を用いてガラス塊を予め加熱することが好ましい。ガラス塊の加熱は、ガラスの粘度が１０９ｄＰａ・ｓ以下、１０７．６ｄＰａ・ｓ以下、１０６．５ｄＰａ・ｓ以下、特に１０５．４ｄＰａ・ｓ以下となる温度で行うことが好ましい。ガラスの粘度が高すぎると、モールドプレス成形に要する時間が長くなる傾向がある。一方、ガラスの粘度が低すぎると、ガラスプリフォームが高温になり、金型も同時に高温になって劣化が進みやすくなる。次に加熱されたガラス塊を、ガラスの軟化点付近まで加熱された少なくとも凹部または凸部を有する金型内に充填し、所望の形状が形成されるまで圧力を印加しモールドプレス成形を行う。ここで、モールドプレス成形時の雰囲気は、金型の酸化による劣化を防止するため、真空または非酸化性であることが好ましい。非酸化性気体としては、例えば水素等の還元性ガス、あるいは窒素、アルゴン等の不活性ガスが挙げられる。なかでも、取扱いが比較的容易であり、かつ安価であることから窒素を用いることが好ましい。モールドプレス成形後、室温まで徐冷し、所定形状のガラスプリフォームを得る。 Prior to mold press molding, it is preferable to preheat the glass lump using an electric furnace or the like. The glass lump is heated at a temperature at which the viscosity of the glass is 10 9 dPa · s or less, 10 7.6 dPa · s or less, 10 6.5 dPa · s or less, particularly 10 5.4 dPa · s or less. Is preferred. If the viscosity of the glass is too high, the time required for mold press molding tends to increase. On the other hand, when the viscosity of the glass is too low, the glass preform becomes high temperature, and the mold becomes high temperature at the same time, and the deterioration easily proceeds. Next, the heated glass lump is filled into a mold having at least a concave portion or a convex portion heated to the vicinity of the softening point of the glass, and pressure is applied until a desired shape is formed to perform mold press molding. Here, the atmosphere during mold press molding is preferably vacuum or non-oxidizing in order to prevent deterioration of the mold due to oxidation. Examples of the non-oxidizing gas include a reducing gas such as hydrogen, or an inert gas such as nitrogen and argon. Among these, it is preferable to use nitrogen because it is relatively easy to handle and inexpensive. After mold press molding, it is gradually cooled to room temperature to obtain a glass preform having a predetermined shape.
　なおガラス塊は、上記製法以外に、溶融ガラスを逆円錐型の成形型上に滴下させて冷却しながら球あるいは楕円球形状等の略球状に成形されたものを用いても良い。この際、滴下成形されたガラスを室温まで一度冷却してから再度、ガラスの粘度が１０９ｄＰａ・ｓ以下となる温度まで加熱してモールドプレスに供する以外に、滴下成形されたガラスの冷却過程でガラスの粘度が１０９ｄＰａ・ｓ以下となる温度になった時点で金型へ移載し、モールドプレス成形に供する方法も採用できる。 In addition to the above manufacturing method, the glass lump may be formed by dropping molten glass onto an inverted conical mold and cooling it into a substantially spherical shape such as a sphere or an elliptical sphere. At this time, after cooling the drop-formed glass once to room temperature, it is heated again to a temperature at which the viscosity of the glass becomes 10 9 dPa · s or less and used for a mold press. Then, when the viscosity of the glass reaches a temperature of 10 9 dPa · s or less, it can be transferred to a mold and used for mold press molding.
　本発明のガラスプリフォームを用いて、モールドプレス成形を行うことにより、レンズを得ることができる。ここでモールドプレス成形方法は特に限定されないが、ガラスプリフォームの製造方法で用いられる、上述のモールドプレス成形と同様の方法が挙げられる。 A lens can be obtained by performing mold press molding using the glass preform of the present invention. Although the mold press molding method is not specifically limited here, The method similar to the above-mentioned mold press molding used with the manufacturing method of a glass preform is mentioned.
　プレス金型の材料としては、ＳＵＳ系、カーバイド等の超硬金属、Ｃｏ系、カーボン系などを用いることができる。離型膜が必要な場合は、Ｐｔ等の貴金属系、ＤＬＣなどのカーボン系、窒化物系の離型膜を使用することが可能である。 As the material of the press die, SUS, carbide or other hard metal, Co, carbon or the like can be used. When a release film is necessary, it is possible to use a noble metal type such as Pt, a carbon type such as DLC, or a nitride type release film.
　以下、本発明を実施例に基づいて詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.
　（実施例１）
　ＳｉＯ２－Ｂ２Ｏ３系の組成になるようにガラス原料を調合し、白金ルツボを用いて１３００℃で２時間溶融した。溶融後、ガラス融液をインゴット状に成形し、アニールを行った。得られたインゴットについてガラス転移点を測定したところ５００℃であった。 Example 1
Glass raw materials were prepared so as to have a SiO 2 —B 2 O 3 -based composition, and were melted at 1300 ° C. for 2 hours using a platinum crucible. After melting, the glass melt was shaped into an ingot and annealed. It was 500 degreeC when the glass transition point was measured about the obtained ingot.
　インゴットを所望の寸法に切断および研磨を行い、鏡面を有する球状のガラス塊を作製した。ガラス塊を電気炉内で粘度が１０５．３ｄＰａ・ｓとなる温度付近まで加熱し、ガラスの粘度が１０１０．３ｄＰａ・ｓとなる温度付近まで加熱されたメニスカス形状が形成される金型内に充填し、窒素雰囲気下で所望の形状が形成されるまで圧力を印加しモールドプレス成形を行った。モールドプレス成形後、室温まで徐冷し、図１（ｃ）に示すような、メニスカス形状のガラスプリフォームを得た。 The ingot was cut and polished to a desired size to produce a spherical glass lump having a mirror surface. Gold that forms a meniscus shape in which a glass lump is heated to near a temperature at which the viscosity becomes 105.3 dPa · s in an electric furnace and the viscosity of the glass is heated to around 10 10.3 dPa · s. The mold was filled and pressure was applied until a desired shape was formed in a nitrogen atmosphere, and mold press molding was performed. After mold press molding, it was gradually cooled to room temperature to obtain a meniscus glass preform as shown in FIG.
　作製したガラスプリフォームの形状、寸法は次の通りであった。 The shape and dimensions of the produced glass preform were as follows.
　　外径：２０．０ｍｍ
　　厚み（中心部）：３．０ｍｍ
　　曲率半径１（凹面）：－２０．０ｍｍ
　　曲率半径２（凸面）：－３０．０ｍｍ
　　曲率半径３（境界部分Ｂ）：７００μｍ Outer diameter: 20.0mm
Thickness (center): 3.0mm
Curvature radius 1 (concave surface): -20.0mm
Curvature radius 2 (convex surface): -30.0 mm
Curvature radius 3 (boundary portion B): 700 μm
　同様の手順にて作製した１０個のガラスプリフォームにつき体積バラツキを測定したところ、±０．１％以内であった。 The volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ± 0.1%.
　なお、ガラスプリフォーム表面の圧縮応力層における圧縮応力は４８ＭＰａであった。圧縮応力の測定は光弾性法により行った。 The compressive stress in the compressive stress layer on the glass preform surface was 48 MPa. The compression stress was measured by the photoelastic method.
　得られたガラスプリフォームの表面は鏡面であり、シャーマークやシワ等の表面の起伏は存在しなかった。また、ガラスプリフォームの表面には金型の研磨跡に起因する線状突起が形成されていた。その線幅は０．５μｍで高さは０．１μｍであった。側面に接触する金型表面は鏡面であったため、得られたガラスプリフォームの側面部分も鏡面となった。 The surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform. The line width was 0.5 μm and the height was 0.1 μm. Since the mold surface contacting the side surface was a mirror surface, the side surface portion of the obtained glass preform was also a mirror surface.
　得られたガラスプリフォームを用いて、上記と同様の手法にてモールドプレス成形を行い、メニスカス形状のレンズを得た。この際、モールドプレス成形時の充填不足や割れは発生しなかった。また、得られたレンズの側面部分も鏡面となった。 Using the obtained glass preform, mold press molding was performed in the same manner as described above to obtain a meniscus lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens also became a mirror surface.
　（実施例２）
　ＳｉＯ２－Ｂ２Ｏ３系の組成になるようにガラス原料を調合して溶融し、ガラス融液をノズルから逆円錐形状の金型上に滴下して冷却しながら楕円球形状に成形した。得られた楕円球状のガラス塊を電気炉内で粘度が１０４．８ｄＰａ・ｓとなる温度付近まで加熱し、ガラスの粘度が１０８．６ｄＰａ・ｓとなる温度付近まで加熱された両凸形状が形成される金型内に充填し、窒素雰囲気下で形状が形成されるまで圧力を印加しモールドプレス成形を行った。モールドプレス成形後、室温まで徐冷し、図１（ａ）に示すような、両凸形状のガラスプリフォームを得た。モールドプレス時の充填不足や割れ、ガラスと金型の融着などの不良は発生しなかった。 (Example 2)
A glass raw material was prepared and melted so as to have a SiO 2 —B 2 O 3 -based composition, and the glass melt was dropped onto an inverted conical mold from a nozzle and formed into an elliptical sphere shape while cooling. The obtained oval spherical glass lump was heated in an electric furnace to a temperature where the viscosity was 10 4.8 dPa · s, and the glass was heated to a temperature where the viscosity was 10 8.6 dPa · s. A mold in which a convex shape was formed was filled, and pressure was applied until the shape was formed in a nitrogen atmosphere, and mold press molding was performed. After mold press molding, it was gradually cooled to room temperature to obtain a biconvex glass preform as shown in FIG. There were no defects such as insufficient filling or cracking at the time of mold pressing, or fusion between the glass and the mold.
　作製したガラスプリフォームの形状、寸法は次の通りであった。 The shape and dimensions of the produced glass preform were as follows.
　　外径：２５．０ｍｍ
　　厚み（中心部）：５．０ｍｍ
　　曲率半径１：５０．０ｍｍ
　　曲率半径２：－５０．０ｍｍ
　　曲率半径３（境界部分Ｂ）：１４００μｍ Outer diameter: 25.0mm
Thickness (center): 5.0mm
Curvature radius 1: 50.0mm
Curvature radius 2: -50.0mm
Curvature radius 3 (boundary portion B): 1400 μm
　同様の手順にて作製した１０個のガラスプリフォームにつき体積バラツキを測定したところ、±１％以内であった。 The volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ± 1%.
　なお、ガラスプリフォーム表面の圧縮応力層における圧縮応力は１２ＭＰａであった。 The compressive stress in the compressive stress layer on the surface of the glass preform was 12 MPa.
　得られたガラスプリフォームの表面は鏡面であり、シャーマークやシワ等の表面の起伏は存在しなかった。また、ガラスプリフォームの表面には金型の研磨跡に起因する線状突起が形成されていた。その線幅は０．１μｍで高さは０．０５μｍであった。側面に接触する金型表面は粗面であったため、得られたガラスプリフォームの側面部分も粗面となった。粗面を形成する線状痕はプレスによる金型面が転写されてできたものであり、凸形状であった。 The surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform. The line width was 0.1 μm and the height was 0.05 μm. Since the mold surface in contact with the side surface was rough, the side surface portion of the obtained glass preform was also rough. The linear trace forming the rough surface was formed by transferring the mold surface by pressing, and had a convex shape.
　得られたガラスプリフォームを用いて、上記と同様の手法にてモールドプレス成形を行い、両凸形状のレンズを得た。この際、モールドプレス成形時の充填不足や割れは発生しなかった。また、得られたレンズの側面部分も粗面となった。 Using the obtained glass preform, mold press molding was performed in the same manner as described above to obtain a biconvex lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens was also rough.
　（実施例３）
　実施例１で得られたガラス塊を用い、ガラス塊を電気炉内でガラスの粘度が１０４．６ｄＰａ・ｓとなる温度付近まで加熱した以外は、実施例１と同一条件でプレス成形を行い、ガラスプリフォームを作製した。この際、表面に非球面形状が形成されるよう、光学有効面に対応する箇所が非球面形状に加工された金型を使用した。 (Example 3)
Using the glass lump obtained in Example 1, press molding was performed under the same conditions as in Example 1 except that the glass lump was heated in the electric furnace to near the temperature at which the viscosity of the glass became 10 4.6 dPa · s. And a glass preform was produced. At this time, a mold was used in which a portion corresponding to the optically effective surface was processed into an aspheric shape so that an aspheric shape was formed on the surface.
　作製したガラスプリフォームの形状、寸法は次の通りであった。 The shape and dimensions of the produced glass preform were as follows.
　　外径：２０．０ｍｍ
　　厚み（中心部）：３．０ｍｍ
　　曲率半径１（凹面）：－２０．０ｍｍ
　　曲率半径２（凸面）：－３０．０ｍｍ
　　コーニック係数ｋ：－０．７９０ Outer diameter: 20.0mm
Thickness (center): 3.0mm
Curvature radius 1 (concave surface): -20.0mm
Curvature radius 2 (convex surface): -30.0 mm
Cornic coefficient k: -0.790
　同様の手順にて作製した１０個のガラスプリフォームにつき体積バラツキを測定したところ、±１％以内であった。 The volume variation of 10 glass preforms produced in the same procedure was measured and found to be within ± 1%.
　得られたガラスプリフォームの表面は鏡面であり、シャーマークやシワ等の表面の起伏は存在しなかった。また、ガラスプリフォームの表面には金型の研磨跡に起因する線状突起が形成されていた。その線幅は０．１μｍで高さは０．０５μｍであった。ガラスプリフォーム側面に接触する金型表面は粗面であったため、得られたガラスプリフォームの側面部分も粗面となった。粗面を形成する線状痕はプレスによる金型面が転写されてできたものであり、凸形状であった。 The surface of the obtained glass preform was a mirror surface, and there were no surface undulations such as shear marks and wrinkles. Further, linear protrusions resulting from the polishing marks of the mold were formed on the surface of the glass preform. The line width was 0.1 μm and the height was 0.05 μm. Since the mold surface in contact with the side surface of the glass preform was rough, the side surface portion of the obtained glass preform was also rough. The linear trace forming the rough surface was formed by transferring the mold surface by pressing, and had a convex shape.
　得られたガラスプリフォームを用いて、上記と同様の手法にてモールドプレス成形を行い、非球面メニスカス形状のレンズを得た。この際、モールドプレス成形時の充填不足や割れは発生しなかった。また、得られたレンズの側面部分も粗面となった。 Using the obtained glass preform, mold press molding was performed in the same manner as described above to obtain an aspheric meniscus lens. At this time, there was no insufficient filling or cracking during mold press molding. Moreover, the side part of the obtained lens was also rough.
　　本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは当業者にとって明らかである。
　本出願は、２０１０年１月６日出願の日本特許出願（特願２０１０-００１１２３）、２０１０年１１月２５日出願の日本特許出願（特願２０１０-２６１８９６）に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on January 6, 2010 (Japanese Patent Application No. 2010-001123) and a Japanese patent application filed on November 25, 2010 (Japanese Patent Application No. 2010-261896). Incorporated herein by reference.
　本発明により、複雑な形状をガラス表面に形成する場合であっても体積精度に優れ、表面精度が高く、またシワやシャーマーク等の不具合がないため表面品位に優れたガラスプリフォームを得ることが可能となる。また、本発明のガラスプリフォームの製造工程において、モールドプレス成形後の研削および研磨工程を省略できるため、廃棄ガラスによるコストや環境面の問題も解決することができる。さらに、本発明のガラスプリフォームをプレス成形することにより光学的な像の乱れの発生がほとんどないレンズを得ることもできる。 According to the present invention, even when a complicated shape is formed on the glass surface, a glass preform having excellent volume accuracy, high surface accuracy, and no defects such as wrinkles and shear marks is obtained. Is possible. Moreover, in the manufacturing process of the glass preform of the present invention, since the grinding and polishing steps after mold press molding can be omitted, the cost and environmental problems due to the waste glass can be solved. Furthermore, it is possible to obtain a lens with almost no optical image disturbance by press-molding the glass preform of the present invention.
　１　ガラスプリフォーム
　Ｌ　光学有効面
　Ｓ　側面部
　Ｂ　境界部分 1 Glass preform L Optically effective surface S Side part B Boundary part

Claims (12)

  1. 　ガラス塊のモールドプレス成形体からなり、かつ、表面が未研磨であるガラスプリフォーム。 A glass preform that consists of a molded body of glass lump and has an unpolished surface.
  2. 　両凸、両凹、メニスカス、平凸および平凹から選択されるいずれかのレンズ近似形状を有する請求項１に記載のガラスプリフォーム。 The glass preform according to claim 1, having a lens approximate shape selected from biconvex, biconcave, meniscus, plano-convex and plano-concave.
  3. 　光学有効面が非球面形状である請求項１または２に記載のガラスプリフォーム。 The glass preform according to claim 1 or 2, wherein the optically effective surface has an aspherical shape.
  4. 　ガラス塊のガラス転移点が７００℃以下である請求項１～３のいずれかに記載のガラスプリフォーム。 The glass preform according to any one of claims 1 to 3, wherein the glass transition point of the glass block is 700 ° C or lower.
  5. 　ガラスプリフォーム表面にプレス金型由来の粗面が転写されている請求項１～４のいずれかに記載のガラスプリフォーム。 The glass preform according to any one of claims 1 to 4, wherein a rough surface derived from a press mold is transferred to the surface of the glass preform.
  6. 　光学有効面以外の箇所にプレス金型由来の粗面が転写されている請求項１～５に記載のガラスプリフォーム。 The glass preform according to any one of claims 1 to 5, wherein a rough surface derived from a press mold is transferred to a portion other than the optically effective surface.
  7. 　光学有効面と側面部との境界部分が凸曲面状である請求項１～６のいずれかに記載のガラスプリフォーム。 The glass preform according to any one of claims 1 to 6, wherein a boundary portion between the optically effective surface and the side surface is a convex curved surface.
  8. 　表面に圧縮応力層が形成されている請求項１～７のいずれかに記載のガラスプリフォーム。 The glass preform according to any one of claims 1 to 7, wherein a compressive stress layer is formed on the surface.
  9. 　請求項１～８のいずれかに記載のガラスプリフォームをモールドプレス成形してなるレンズ。 A lens formed by mold-pressing the glass preform according to any one of claims 1 to 8.
  10. 　光学有効面以外の箇所にプレス金型由来の粗面が転写されている請求項９に記載のレンズ。 The lens according to claim 9, wherein a rough surface derived from a press mold is transferred to a portion other than the optically effective surface.
  11. 　溶融ガラスを成形して所定形状のガラス塊を製造すること、および少なくとも凹部または凸部を有する金型を用いて当該ガラス塊をモールドプレス成形することを含むガラスプリフォームの製造方法。 A method for producing a glass preform, which includes forming molten glass to produce a glass lump of a predetermined shape, and mold pressing the glass lump using a mold having at least a concave portion or a convex portion.
  12. 　モールドプレス成形する前に、ガラス塊を１０９ｄＰａ・ｓ以下の粘度となるように加熱することを含む請求項１１に記載のガラスプリフォームの製造方法。 The method for producing a glass preform according to claim 11, comprising heating the glass lump so as to have a viscosity of 10 9 dPa · s or less before mold press molding.
PCT/JP2010/073180 2010-01-06 2010-12-22 Glass preform and method of manufacture thereof WO2011083692A1 (en)

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JP2011157258A (en) 2011-08-18
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TW201130752A (en) 2011-09-16

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