JP4094573B2 - Manufacturing method of glass optical element - Google Patents

Description

  The present invention relates to a method of supplying a glass material to be molded to a mold and an apparatus for use in this method. Furthermore, this invention relates to the manufacturing method of the glass optical element containing glass optical elements, such as a high precision lens, which does not require grinding and grinding | polishing after press molding using the method of the said invention. In particular, the present invention relates to a method for producing a glass optical element having higher surface accuracy with high production efficiency.

  In recent years, there are various molding methods for glass optical elements such as high-precision lenses that do not require grinding or polishing after press molding, using molds that are made by precision processing of mold materials that do not fuse softened glass and can be mirror finished. Has been developed. In order to obtain the required lens by press molding, the surface shape accuracy and surface quality (smooth surface roughness) as well as specifications such as thickness, outer diameter, and eccentricity must be satisfied. Of course, the internal quality such as refractive index and transmittance is good.

  Furthermore, in putting such a glass optical element molding method into practical use, it is a big problem how much productivity can be obtained. That is, it is a big problem whether more glass optical elements can be produced in a shorter time. One of the means for improving productivity is to process a plurality of glass materials in parallel, and the other is to shorten the processing time for one time. Various improved methods have been proposed for each. In order to shorten the processing time for one time, it is necessary to further shorten the heating / cooling cycle of the mold, and therefore, various glass conditions at the time of molding and temperature conditions of the mold are devised.

For example, in Japanese Patent Application Laid-Open No. 7-10556 (Patent Document 1), a glass material having a viscosity in the range of 10 ⁷ to 10 ⁹ poise is formed into a mold having a temperature at which the glass material exhibits a viscosity of 10 ¹⁰ to 10 ¹² poise. Describes the method of pressure molding. Japanese Patent Application Laid-Open No. 9-12317 (Patent Document 2) discloses a glass material having a viscosity in the range of 10 ^5.5 to 10 ⁹ poise and a mold having a temperature at which the glass material exhibits a viscosity of 10 ⁸ to 10 ¹² poise ( However, a method is described in which the temperature of the mold is lower than that of the glass material. In either method, the temperature of the mold is not increased unnecessarily, thereby shortening the time required for temperature increase and decrease and reducing the cycle time.

  As described above, a method for molding a glass optical element such as a high-precision lens using a molding die obtained by precision processing of a mold material that can be mirror-polished without softened glass has attracted attention and has been developed in recent years. Yes. Further, in any method, in order to prevent deterioration of the molding surface of the molding die, the glass material heated and softened at a place other than the molding die is transferred to the molding die before molding and molded. For example, the glass material to be molded is usually formed in the form of a spherical or marble (flattened spherical) preform, which is transferred to the upper part of the lower part of the mold by a flotation plate or a suction pad, and then dropped. Supplied to the mold.

For example, in Japanese Patent Laid-Open No. 6-340430 (Patent Document 3), molten glass is conveyed by a floating plate that is made of a split mold that can be opened and closed in the horizontal direction, and ejects gas from the surface of the porous member. A method of opening a split mold on a mold and supplying glass to the mold is disclosed. Japanese Patent Laid-Open No. 8-133758 (Patent Document 4) discloses that a glass preform has an opening diameter smaller than, equal to, or larger than the diameter of the glass preform and supplies airflow to the bottom thereof. A porous levitation jig that has a spherical surface or a plane that approximates the curvature of the outer diameter of the glass press is softened by heating using a levitation jig provided with a single pore while being levitated by the air flow from the pore. A method is disclosed in which a glass preform that has been softened by heating while being floated by an air flow from a porous body and supplied to a mold by dropping the heat-softened glass preform is disclosed. Japanese Patent Laid-Open No. 8-259242 (Patent Document 5) discloses that a glass preform is blown out from a plurality of pores near the center using a levitating jig having a trumpet-shaped upper opening. A method is disclosed in which a glass preform softened by heating while being floated and floated by an air flow and supplied to a mold by dropping the heat-softened glass preform.
Japanese Patent Laid-Open No. 7-10556 JP-A-9-12317 JP-A-6-340430 JP-A-8-133758 JP-A-8-259242

  However, when the glass material to be molded is supplied to the mold (lower mold) by dropping naturally as in the above method, there are the following problems depending on the shape and size (weight) of the glass material to be molded. It was. For example, in a relatively small glass material to be molded, due to the state of the air current in the middle of dropping or contact with a floating dish, etc., it may not fall on the molding surface of the lower mold and jump out of the molding mold . Alternatively, in the case of a non-spherical glass material to be molded, even if it falls on the lower mold, its position may deviate from the center of the molding surface. When molding is performed in such a state, the molding material is uniformly in the mold. In some cases, uneven thickness occurs, and the molding material protrudes from the mold, resulting in defective products. In particular, the glass preform that is levitating due to the air current is rotating or vibrating slightly up and down, left and right, so when dropping such a glass preform, the glass preform at the start of dropping is It is in an unstable state. Therefore, in such a case, the above problem is likely to occur.

  Accordingly, an object of the present invention is to provide a method and an apparatus capable of preventing the glass material to be molded from jumping out of the mold during the dropping when the glass material to be molded is supplied to the mold by dropping. Furthermore, an object of the present invention is to provide a method and an apparatus capable of positioning a glass material to be molded at substantially the center of a molding surface of a lower mold when supplying the glass material to the mold by dropping the glass material to be molded. It is in. In addition, an object of the present invention is to provide a method for producing a glass optical element that prevents the glass material to be molded from popping out of the mold and the generation of defective products using the above method.

  The present invention is a method for supplying a glass material to be molded by dropping it from above onto a molding surface of a lower mold of an upper mold and a lower mold, and a guide means for dropping the glass material to be molded And a method of supplying the glass material to be formed (hereinafter referred to as “supply method 1”), characterized in that the guide means is provided at a position where the glass material to be dropped falls on the molding surface of the lower mold. To do.

  Further, the present invention is a method of supplying a glass material to be molded onto a molding surface of a lower mold of an upper mold and a lower mold, and after the glass material to be molded is fed onto a molding surface of the lower mold A method of supplying a glass material to be formed, wherein the position of the glass material to be molded is corrected so that the vertical center of the glass material to be molded and the center point of the molding surface of the lower mold substantially coincide with each other. (Hereinafter referred to as “supply method 2”).

  Furthermore, the present invention is a guide means used in a method for supplying a glass material to be molded by dropping it from above onto a molding surface of a lower mold of an upper mold and a lower mold. Provided is a guide means characterized by having a guide section that forms a material drop passage and can drop a glass material to be molded.

  Furthermore, the present invention is a means used in a method for correcting the position of a glass material to be molded supplied on a molding surface of a lower mold of a molding die composed of an upper mold and a lower mold, A glass material contact portion to be molded for contact and movement; and the glass material contact portion to be molded has a ring-shaped opening end surface or a protrusion arranged on a concentric circle. A characteristic position correction means is provided.

  Further, the present invention is a glass optical element characterized in that the glass material to be molded supplied to the molding surface of the lower mold is pressure-molded by using the method 1 or 2 of supplying the glass material to be molded of the present invention. It relates to the manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, when supplying a shaping | molding glass raw material to a shaping | molding die by dropping, the method and apparatus which can be prevented from jumping out of the shaping | molding glass material in the middle of dropping can be provided. Furthermore, according to the present invention, in supplying a glass material to be molded by dropping the glass material to be molded, a method and an apparatus capable of positioning the glass material to be molded substantially at the center of the molding surface of the lower mold are provided. Can do. By using the method and apparatus for supplying an optical element molding material according to the present invention, it is possible to stably produce an optical element with good quality.

(Supply method 1)
The supply method 1 of the present invention is a method of supplying a glass material to be formed by dropping it from above onto the lower mold surface of the mold consisting of an upper mold and a lower mold, preferably by dropping naturally. There are no particular restrictions on the type, shape, material, etc. of the mold to which the glass material is supplied. There is no restriction | limiting also in the material, shape, etc. of a to-be-molded glass raw material, For example, a shape may be spherical shape or a marble shape. The glass material to be molded can be, for example, a glass preform or a glass gob, and may be in a heated and softened state or in an unheated state. However, since the supply onto the molding surface of the lower mold by dropping the glass material to be molded is effective in the heat-softened state, the supply method of the present invention is also particularly effective in the case of the glass material to be molded in the heat-softened state. It is. The glass glass material is dropped from above, for example, by placing or moving the suction pad that has adsorbed the glass material to be moved above the lower mold, and then releasing the adsorption, or by an air flow that ejects the glass material to be molded. This can be done by placing or moving the detachable floating dish that is held above the lower mold and then dividing the floating dish.

  In the method of the present invention, the glass material to be molded is dropped, but it is preferable that the glass material to be molded is dropped substantially vertically. In the method of the present invention, guide means for dropping the glass material to be molded substantially vertically is used, and the guide means is provided at a position where the glass material to be molded falls on the molding surface of the lower mold. Specifically, the guide means may have a guide portion that forms a drop passage for the glass material to be molded and that can drop the glass material to be formed substantially vertically. The guide portion forming the glass passage of the glass member to be guided may have any structure and shape as long as it can guide the glass material to be formed on the molding surface of the lower mold. For example, it may have a plate shape (see FIGS. 1 and 2) provided with a through hole, a cylindrical shape (see FIG. 3), a funnel shape (see FIG. 4), a ring shape with legs (see FIG. 5), and the like. The guide means will be described in detail later.

The guide means is inserted between the molding glass material transfer position and the lower mold before or after the molding glass material is transferred to the upper side of the lower mold or simultaneously with the transfer. The guide means is preferably arranged in the vicinity of the lower mold from the viewpoint that the glass material to be molded can be effectively prevented from jumping out of the mold. In addition, it is preferable that the guide means be used by heating in order to maintain the temperature of the glass material to be molded. In particular, when the glass material to be molded is heated and softened to about 10 ^5.5 to 10 ⁸ poise, the glass material to be molded is heated to a temperature at which a so-called chill mark is not formed on the glass surface by contacting the guide means. For example, the temperature is preferably higher than the temperature of (glass transition point -200 ° C.) of the glass material to be molded. Further, from the viewpoint of preventing fusion between the guide means and the glass material to be molded, for example, near the glass transition point of the glass material to be molded (glass transition point ± 100 ° C., more preferably glass transition point ± 50 ° C.), or It is preferable that it is less than that.

(Guide means)
The guide means of the present invention has a guide portion that forms a drop passage for the glass material to be formed and can drop the glass material to be formed substantially vertically. The guide means also has means for moving the guide portion. It is preferable that the falling passage of the glass material to be molded has an inner diameter slightly larger than the diameter of the glass material to be molded to be passed. A passage having an inner diameter that decreases downward and a minimum inner diameter slightly larger than the diameter of the glass material to be molded is more preferable. The guide means may have any shape as long as it has a passage for the glass material to be molded and has a guide portion that can regulate the dropping position of the glass material to be molded in the horizontal direction. The guide portion may be, for example, a thick plate provided with a through hole (see FIG. 1). The through hole preferably has a funnel shape with at least a portion narrowing downward (FIG. 2). Further, the guide portion may be a substantially cylindrical member (see FIG. 3). Further, the guide portion may be a funnel-shaped member that is at least partially narrowed downward (see FIG. 4). The guide portion may be formed by projecting three or more leg members on the ring. Preferably, each leg member is inclined toward the center of the ring from the base to the tip (see FIG. 5).

  Further, as shown in FIG. 6, a molding die is formed by assembling a plurality of upper molds (not shown) and lower molds 3 in each of an upper mother mold (not shown) and a lower mother mold 2. In the case of molding a molded product, the guide portion 1 has a shape that substantially follows the shape of the upper surface of the mother die, and a plurality of through holes are in the lower die assembly position, and all the through holes are lower die when set. And can be formed concentrically (see FIG. 6). Also in this case, it is preferable that at least a part of the through hole has a funnel shape that narrows downward (see FIG. 7). The material of the guide means is not particularly limited as long as it is a heat resistant material. For example, it can be a metal, a ceramic, or a carbon material. The dropping path of the glass material to be molded of the guide means may be subjected to surface processing so as to allow the glass material to slide. In order to guide the glass material to be molded more smoothly and to prevent the glass material to be molded from being scratched or the like, it is preferable that the corners existing in the above shapes are curved.

  In the present invention, the guide means gives the glass material to be formed at a desired position by applying a drag including a vector component toward the position (center of the mold) to be landed at a predetermined timing of the dropping process of the glass material to be formed. Landing. Accordingly, the position of the guide means used in the present invention is also important in order to perform such correction at a predetermined timing. For example, the operation of the guide means of the present invention is as follows. When the glass material to be molded is one that has been levitated by an air current before dropping, the glass material to be molded often performs a rotational motion or a vibration motion. At this time, if the glass material is released from the floating due to the gas in order to drop the glass material to be molded, inertial force based on the rotational motion and vibration motion acts on the glass material to be molded, and the horizontal position deviates from the opened position. Will land on the position. In addition, since the direction of action of kinetic energy of the glass material to be molded changes regularly or irregularly, the magnitude of the deviation and the direction of the deviation differ depending on the state of opening. However, when the guide means is used, a drag having a horizontal vector component toward the landing position (the center of the mold) is applied to the horizontal inertia force that is the cause of the deviation. The position can be adjusted. Here, the timing for applying the drag can be selected by selecting the height and shape of the guide means. That is, by providing the guide means at a relatively high position, the drag can be applied to the glass material to be molded at a relatively early stage during dropping. Further, by providing the guide means at a relatively low position, the drag can be applied to the glass material to be molded at a stage relatively close to the end during dropping.

  At this time, providing a plurality of guide means or using a guide means having a large vertical direction makes contact between the glass material to be molded and the guide means (that is, the glass material to be molded receives the drag from the guide means). Work to increase timing. For example, the guide means in FIG. 3 tends to have more timing when the guide means applies the drag to the glass material to be molded than the guide means in FIG. The shape and material of the guide means influence the direction of the drag and the magnitude of the drag. At this time, increasing the size of the guide means in the vertical direction can widen the range of height to which the drag is applied.

(Supply method 2)
The supply method 2 of the present invention is a method of supplying the glass material to be molded onto the molding surface of the lower mold of the upper mold and the lower mold. It is almost the same. However, this method is particularly effective when the shape of the glass material to be molded is a substantially spherical shape other than a true sphere. Even if the spherical glass material to be formed is not supplied to the center of the molding surface, it may rotate and move naturally to the center of the molding surface depending on the state of the glass. On the other hand, in the case of a spherical shape other than a true sphere, for example, a flat spherical shape such as a marble shape, if it is not supplied to the center of the molding surface, it will rotate and move naturally to the center of the molding surface. Because it is difficult. In addition, supply to the lower mold | type of a glass material to be molded can be performed by well-known methods, such as dropping from a suction pad, a floating plate, etc., Preferably, it is performed by the supply method 1 of this invention.

  In the supply method 2 of the present invention, after the glass material to be molded is supplied onto the molding surface of the lower mold, the position of the glass material to be molded is set to the center in the vertical direction of the glass material to be molded and the center of the molding surface of the lower mold. Is corrected to substantially match. Thereby, since the glass material to be molded spreads uniformly in the mold, uneven thickness can be prevented, and therefore it is possible to prevent the glass material to be molded from protruding from the mold or causing defective products. For the correction of the position of the glass material to be molded, for example, a position correcting means having a glass material abutting portion whose opening end surface has a ring-shaped glass material abutting portion or projections arranged concentrically is used. Can be done. The structure of the position correcting means will be described later in detail.

  To correct the position, place the molding glass material contact portion so that the vertical center of the molding glass material contact portion coincides with the center point of the molding surface of the lower mold, and bring the molding glass material contact portion into contact with the molding glass material. However, it can be done by descending vertically. That is, after supplying the glass material to be molded onto the molding surface of the lower mold, the position correcting means is arranged above the lower mold so that the center of the glass material abutting portion coincides with the center point of the molding surface of the lower mold. Or move it. Next, the position can be corrected by lowering the position correcting means and bringing it into contact with the periphery of the uneven thickness portion of the glass material to be formed, and further lowering the position correcting means while making contact. The position correcting means can be, for example, a means having a ring 4 having a diameter slightly larger than the diameter of the glass material to be molded as shown in FIG. In this case, the position can be corrected as follows. The ring 4 is arranged so that the center thereof coincides with the center 6b of the molding surface 6a of the lower mold 6 (see FIG. 8A). Next, the ring 4 is lowered vertically and brought into contact with the glass material 5 to be molded (see FIG. 8B). Furthermore, by lowering the curved surface of the glass material 5 to be molded while being pushed by the ring 4, the center 5a of the glass material 5 to be molded can be moved so as to approach the center 6b of the molding surface 6a (see FIG. 8C).

  In addition to the ring shape as described above, the abutting member of the position correcting means with the glass material to be molded is, for example, a glass material to be molded such as a glass material abutting portion having protrusions arranged concentrically. Any shape can be used as long as it can come into contact with the lower mold at a concentric position. The structure and the like of the position correction means will be described in detail next. Further, it is preferable that the position correcting means is used by heating in order to maintain the temperature of the glass material to be molded. In addition, although there is no restriction | limiting in the heating temperature of a position correction means, For example, it can be below the glass transition point of a to-be-molded glass raw material.

(Position correction means)
The position correcting means may be of any shape as long as it comes into contact with the glass material to be molded at a position concentrically with the lower mold. For example, the position correcting means has a ring-shaped or concentric protrusion. It can have a to-be-shaped glass raw material contact part. Further, the position correcting means can be arranged on the lower mold by appropriate lifting means and reciprocating means.

  The position correcting means may be, for example, the ring 4 whose inner diameter is smaller than or substantially the same as the diameter of the glass material to be molded (see FIG. 9A). The cross-sectional shape of the ring may be rectangular, but it is preferable that the contact portion with the glass material to be molded is tapered (see FIG. 9B) or circular (see FIG. 9C). In this case, as described above, the ring 4 is arranged so that the center thereof coincides with the horizontal center of the lower mold 6 (see FIG. 8A), and then lowered vertically to contact the glass material 5 to be molded. Then, the position of the glass material to be molded can be corrected (see FIG. 8C). Any position correcting means of any shape exemplified below can correct the position basically by the same method as long as it is in contact with the glass material to be formed and the lower mold at a concentric position.

  The position correcting means may be, for example, a cylinder whose inner diameter is larger than or equal to the diameter of the glass material to be molded. Further, the position correcting means may have a cylindrical shape in which the inner diameter increases toward the lower end, and at least one portion of the inner diameter is the same as the diameter of the glass material to be molded. In this case, even if the diameter of the glass material to be molded whose position is to be corrected fluctuates somewhat, it can be dealt with. That is, as shown in FIG. 10, when the diameter of the glass material to be molded is substantially the same, the position is corrected in the lower part of the cylinder 7, and as shown in FIG. If is small, the position is corrected in the upper part of the cylinder.

  The position correcting means may be one in which a bowl-shaped depression or a trapezoidal depression whose diameter is narrowed upward is formed on the lower surface of the thick plate (see FIGS. 12 and 13). Further, the position correcting means may be a member formed by projecting three or more leg members concentrically on a ring, a plate body or the like. Preferably, each leg member extends from the base to the tip (see FIG. 14). Further, in the case where the molding die is formed by assembling a plurality of upper dies and lower dies in each of the upper mother die and the lower mother die, the position correcting means has a cross section substantially following the cross sectional shape of the mother die. It has a shape, and a plurality of through holes, bowl-shaped depressions or trapezoidal depressions may be formed at the lower mold assembly position, and all depressions may be concentric with the lower mold when set ( FIG. 15).

  Further, in the case where the molding die is formed by assembling a plurality of upper dies and lower dies on each of the upper mother die and the lower mother die, the position correcting means has a plurality of rings at the lower die assembling position, All rings may be connected so as to be concentric with the lower mold when set (see FIG. 16). The member of the position correcting means is not particularly limited as long as it has a certain degree of heat resistance. For example, it can be a metal, a ceramic, or a carbon-based material. The portion of the position correcting means that comes into contact with the glass material to be molded is preferably subjected to surface processing so that the glass material to be molded can slide. In addition, in order to prevent the glass material to be molded from being scratched, it is preferable that the corners existing in the respective shapes are curved.

Further, it is preferable that the position correcting means is used by heating in order to maintain the temperature of the glass material to be molded. In particular, when the glass material to be molded is heated and softened to about 10 ^5.5 to 10 ⁸ poise, the glass material to be molded is heated to a temperature at which a so-called chill mark is not formed on the glass surface by contacting the position correcting means. For example, the temperature is preferably higher than the temperature of (glass transition point -200 ° C.) of the glass material to be molded. Further, from the viewpoint of preventing fusion between the position correcting means and the glass material to be molded, for example, near the glass transition point of the glass material to be molded (glass transition point ± 100 ° C., more preferably glass transition point ± 50 ° C.), Or it is preferable that it is less.

  The supply methods 1 and 2 of the present invention, the guide means and the position correcting means are described in, for example, JP-A-6-340430, JP-A-8-133758, and JP-A-8-259242. It can be applied to any method of supplying a softened glass preform to a mold.

(Glass optical element manufacturing method)
The glass optical element manufacturing method of the present invention includes a glass material to be molded supplied on the molding surface of the lower mold by the supply method 1 of the present invention, or a glass to be molded whose position is corrected by the supply method 2 of the present invention. A material or a glass material to be molded that is supplied onto the molding surface of the lower mold by the supply method 1 of the present invention and whose position is corrected by the supply method 2 of the present invention is pressure-molded. There are no particular restrictions on the method of pressure-molding the glass material to be molded, the method of preheating the glass material to be molded, and the like.

For example, a method of pressure-molding a glass material to be molded is a method of molding a glass material having a viscosity in the range of 10 ^5.5 to 10 ⁸ poise at a temperature at which the glass material to be molded exhibits a viscosity of 10 ⁸ to 10 ^10.5 poise. A process of initial pressurizing and molding with a mold (however, the temperature of the glass material to be molded is higher than the temperature of the mold), lowering the temperature of the mold and the molded glass (hereinafter referred to as molded glass) below the glass transition point. The process and the process of taking out a shaping | molding glass from a shaping | molding die can be included.

In this method, the glass material is softened by heating to a temperature corresponding to a viscosity of 10 ^5.5 to 10 ⁸ poise. When the viscosity of the glass material is 10 ⁸ poise or less, the glass material can be sufficiently deformed and molded with a mold preheated to a temperature corresponding to a viscosity of 10 ⁸ to 10 ^10.5 poise. Moreover, when the viscosity of the glass material is 10 ^5.5 poise or more, the glass material can be prevented from being greatly deformed by its own weight before molding. In order to stabilize the mold at a relatively low temperature and perform good molding, the glass material is preferably softened by heating to a temperature corresponding to 10 ^6.5 to 10 ^7.6 poise. The preheating temperature of the mold is set to a temperature at which the viscosity of the glass material corresponds to 10 ⁸ to 10 ^10.5 poise. If the viscosity is lower than the temperature corresponding to 10 ^10.5 poise, it becomes difficult to obtain a glass molded body with a thin edge by greatly stretching the glass material, and it is difficult to obtain high surface accuracy, and the viscosity corresponds to 10 ⁸ poise. If the temperature exceeds the temperature, the molding cycle time becomes longer than necessary, and the life of the mold is shortened. The preheating temperature of the mold is preferably a temperature at which the viscosity of the glass material corresponds to 10 ⁸ to 10 ^9.6 poise. Note that the temperature of the mold is set lower than the temperature of the glass material to be molded. By doing in this way, it becomes possible to shorten cycle time and prolong the lifetime of a shaping | molding die.

  Furthermore, it is particularly preferable to set the upper mold temperature lower than the lower mold temperature at the start of initial pressure molding from the viewpoint of preventing the molded body from sticking to the upper mold at the time of mold release. More specifically, it is appropriate that the upper mold temperature is 5 to 20 ° C. lower than the lower mold temperature.

As the mold used in the present invention, a conventionally known mold can be used as it is. However, it is preferable to use a mold whose molding surface is composed of an amorphous and / or crystalline carbon film composed of a single component layer or mixed layer of graphite and / or diamond. In a mold having a molding surface composed of the carbon film as described above, even if the temperature of the mold is equal to or higher than the glass transition point of the glass material, glass fusion (adherence) does not occur. The carbon film is formed by means such as sputtering, plasma CVD, CVD, or ion plating. In the case of forming a film by sputtering, Ar is used as a sputtering gas in a range of a base temperature of 250 to 600 ° C., an RF power density of 5 to 15 W / cm ² , and a vacuum degree of sputtering of 5 × 10 ^{−4 to} 5 × 10 ⁻¹ torr. It is preferable to sputter such an inert gas using graphite as a sputtering target. When the film is formed by the microwave plasma CVD method, it is formed using methane gas and hydrogen gas as source gases under the conditions of a base temperature of 650 to 1000 ° C., a microwave power of 200 W to 1 kW, and a gas pressure of 10 ^{−2 to} 600 torr. A membrane is preferred. When forming by an ion plating method, it is preferable that the base temperature is 200 to 450 ° C. and the benzene gas is ionized. These carbon films include those having C—H bonds.

  Further, the glass material to be molded supplied onto the molding surface of the lower mold is softened by heating the glass material to be molded while being floated by an air flow, and the glass material to be molded that has been softened by heating is dropped. The mold can be supplied. In particular, it is preferable that the glass material to be molded is heated and softened while being floated by an air flow, and the glass material to be heated that has been softened is dropped and transferred to a preheated mold. In a low-viscosity region where the glass material to be formed is deformed by its own weight, it is not easy to prevent the jig holding the glass material to be fused with the glass during heating. In the present invention, for example, the glass material to be molded is floated by the air flow by ejecting gas from the inside of the jig. Gas layers are formed on both the jig surface and the glass surface, so that the jig and the glass can be heated and softened without reacting. Furthermore, when the glass material to be molded is a preform, it can be softened by heating while generally maintaining the shape of the preform. In addition, even when the glass material to be molded is a glass gob and there are surface defects such as wrinkles on the surface with irregular shapes, the shape can be adjusted by levitation by an air flow while softening by heating, and the surface defects can be erased. Is possible.

  There is no restriction | limiting in particular as gas used as the airflow used in order to float a glass raw material to be molded in this invention. However, from the viewpoint that the heated glass material to be molded does not react with the jig and further prevents deterioration of the heated jig due to oxidation, it is preferably a non-oxidizing gas, for example, nitrogen or the like. Is appropriate. A reducing gas such as hydrogen gas can also be added. The flow rate of the airflow can be appropriately changed in consideration of the shape of the mouth for blowing out the airflow, the shape and weight of the glass material to be molded, and the like. In a normal case, a gas flow rate in the range of 0.005 to 20 liters / minute is suitable for floating the glass material to be molded. However, if the gas flow rate is less than 0.005 liter / minute, the glass material to be molded may not be sufficiently floated when the weight of the glass material to be molded is 300 mg or more. In addition, when the gas flow rate exceeds 20 liters / minute, even when the glass weight is 2000 mg or more, the glass on the floating jig is greatly shaken, and when the glass material to be molded is a preform during heating, the shape is Because it may change. Furthermore, the conditions for heat softening of the glass material to be molded can be appropriately changed depending on the type of glass and the like, and are adjusted so as to have a viscosity required for the glass material to be softened.

Hereinafter, the present invention will be described with reference to examples.

Reference Example In a molding apparatus for supplying a glass material to be molded by the method of this reference example , a long upper mold and a lower mold are respectively attached to an upper main spindle and a lower main spindle of the press. (Not shown) and the lower mother die 11 are each attached with six upper molds (not shown) and a lower die 12, respectively. Two induction heating coils 13 wound in a shape imitating the shape are provided around the upper mother die and the lower mother die (see FIG. 17). A 20 mm gap was provided between the upper coil and the lower coil. With this apparatus, barium borosilicate glass (transition point 514 ° C., yield point 545 ° C.) is pressed to form a biconvex lens having an outer diameter of 10 mm.

  Six spherical glass plates 15 are arranged in a line (arranged at equal intervals with the upper and lower molds) on a support arm 14 that can be opened and closed as shown in FIG. On the glassy carbon), it was levitated, heated, and softened by an air current ejected from below. Thereafter, the support arm 14 was inserted between the upper and lower induction heating coils 13 and arranged immediately above the plurality of lower molds 12. At the same time, guide means 17 formed by forming six wax-shaped through holes 16 on the long plate shown in FIG. 19 was inserted between the support arm 14 and the lower mold 12. Thereafter, by quickly opening the support arm 14, the plurality of floating dishes 15 are divided into left and right, and a plurality of glass forming materials are simultaneously dropped from the floating dishes 15 onto the corresponding lower molds 12. It supplied on the type | mold 12 (refer FIG. 20). All the glass materials to be molded were supplied to the center of the lower mold 12. The guide means 17 was set to 400 ° C. lower than the glass transition temperature (514 ° C.) of the glass material to be molded, and the glass material to be molded was not fused to the guide means 17. Immediately thereafter, the support arm and the guide means were retracted from above the lower mold, the high frequency power was turned off, and the lower mother mold was raised to perform pressing. The above operation was repeated 1000 times. As a result, the glass material to be molded did not jump out of the mold, and a stable and good quality lens was obtained.

Example 1
A biconvex lens made of barium borosilicate glass was molded using the same mold as in the reference example . However, in this embodiment, a glass material to be molded (diameter 7 mm, height 4.5 mm) hot-formed into a marble shape is used as the glass material to be molded, and the guide means is used as in the reference example. After the glass material to be molded was dropped from the divided levitation plate to the lower mold, the position was corrected by the position correcting means. As the position correcting means, a ring formed by connecting six rings having an inner diameter slightly larger than the glass material diameter as shown in FIG. 16 was used. First, as shown in FIG. 21, the position correcting means 18 is arranged so that the center of each ring matches the center of the corresponding lower mold (see FIG. 19). Thereafter, the ring was lowered toward the lower mold 20 set on the lower mother mold 19, and each ring was brought into contact with the glass material 21 to be molded on the lower mold 20. When the position correcting means 18 is further lowered, the glass material 21 to be molded slides to the center of the lower mold, whereby the center of the glass material 21 to be molded and the center of the lower mold 20 are aligned, and the correction of the position is completed. Subsequently, it press-molded similarly to the reference example . Under any of the conditions shown in Table 1, a good quality lens was obtained.

温度：℃、粘度：ポアズ

Temperature: ° C, Viscosity: Poise

It is sectional drawing which shows the guide means of the 1st form of this invention. It is sectional drawing which shows the guide means of the other form of this invention. It is sectional drawing which shows the guide means of the other form of this invention. It is sectional drawing which shows the guide means of the other form of this invention. It is an oblique view which shows the guide means of the other form of this invention. It is sectional drawing which shows the guide means of the other form of this invention. It is sectional drawing which shows the guide means of the other form of this invention. It is a figure which shows the usage condition of the position correction means of this invention. It is a figure which shows the position correction means of the 1st form of this invention. It is a figure which shows the usage condition of the position correction means of the other form of this invention. It is a figure which shows the usage condition of the position correction means of the other form of this invention. It is sectional drawing which shows the position correction means of the other form of this invention. It is sectional drawing which shows the position correction means of the other form of this invention. It is a perspective view which shows the position correction means of the other form of this invention. It is sectional drawing which shows the position correction means of the other form of this invention. It is a top view which shows the position correction means of the other form of this invention. It is sectional drawing which shows the shaping | molding apparatus used for the method of one Example of this invention. It is a top view which shows the division | segmentation flotation plate used for the method of one Example of this invention. It is a top view which shows the position correction means used for one Example of this invention. It is sectional drawing which shows the method of one Example of this invention. It is sectional drawing which shows the method of the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide part 3, 6 Lower mold | type 4 Position correction means 5 Molding glass raw material

Claims (5)

In the method of manufacturing a glass optical element, a glass material to be molded is supplied onto a molding surface of a lower mold of an upper mold and a lower mold, and pressure molding is performed.
After the glass material to be molded is supplied onto the molding surface of the lower mold, the position of the glass material to be molded is adjusted using the position correcting means having the glass material abutting part, and the glass material abutting part is molded. The method as described above, wherein the vertical center of the glass material to be molded and the center point of the molding surface of the lower mold are substantially matched by descending vertically while being brought into contact with the glass material. The method according to claim 1, wherein the position correcting means includes a ring-shaped glass material contact portion. The method according to claim 2 or 3, wherein the position correcting means is heated. The method according to claim 3, wherein the position correcting means is heated to a temperature higher than (glass transition point Tg−200 ° C.) of the glass material to be molded. How to pressure molding the glass molding material, 10 ^5.5 to 10 this the glass molding material of the molded glass material having a viscosity in the range of ⁸ poise 10 ⁸ to 10 temperature mold that exhibits a viscosity of ^10.5 poises ( However, the temperature of the glass material to be molded is initially pressurized and molded at a temperature higher than the temperature of the mold, and the temperature of the mold and the molded glass (hereinafter referred to as molded glass) is lowered below the glass transition point. And the manufacturing method of any one of Claims 1-4 including the process of taking out shaping | molding glass from a shaping | molding die.

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