JP2007137723A - Mold set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold set capable of producing a molded glass article with less strain. <P>SOLUTION: The mold set 10 is provided with the columnar upper and lower molds 11 and 12, and a body mold 13. The lower mold 12 is disposed facing the upper mold 11, and the body mold 13 is formed in a cylindrical form so that the upper and lower molds 11 and 12 are slidably inserted thereinto. The linear thermal expansion coefficient of the body mold 13 is equal to or lower than that of the glass material to be press molded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mold set. In detail, it is related with the shaping | molding die set for shape | molding a glass molded object.

  Conventionally, a precision press molding method has been proposed as a method of manufacturing an optical element such as a lens. The precision press molding method is a method of press molding a glass material heated to a predetermined temperature using a molding die.

  In general, since precision press molding of a glass material is performed in a high temperature atmosphere, a molding die made of ceramic or cemented carbide is used for precision press molding. However, in order to produce a mold made of ceramics or cemented carbide, the base material must be cut and ground with high precision using a high-rigidity ultra-precise CNC lathe and the surface must be polished. For this reason, the molds made of ceramics or cemented carbide have a problem that the production cost is high and the time required for the production is long. In addition, since cutting or the like is performed for each mold, there is a problem that variations occur in the shape of the mold.

In view of such a problem, for example, Patent Documents 1 and 2 propose a glass mold. Glass molds can be manufactured by precision press molding, so they do not require cutting, grinding, polishing, etc. unlike molds made of cemented carbide, etc., and can be manufactured at low cost and with high throughput. .
Japanese Patent No. 2616964 Japanese Patent Laid-Open No. 01-033022

  However, relatively distortion remains in the glass mold produced by the conventional precision press molding method. Therefore, when precision press molding is performed using a glass mold produced by the precision press molding method as it is, distortion of the glass mold is gradually eliminated by repeated heating during press molding. Therefore, the shape dimension of the glass mold changes with time. Therefore, there is a problem that it is difficult to stably produce glass optical elements.

  For example, a method of previously reducing strain by annealing (slow cooling) a precision press-molded glass mold is also conceivable. However, the annealing process changes the shape of the glass mold, making it difficult to produce a glass mold having a desired shape.

  Further, when a glass optical element or the like is manufactured by a precision press molding method, distortion of the manufactured optical element becomes a problem. This is because if the strain remains in the optical element, desired optical performance and mechanical durability may not be obtained. In addition, it is conceivable to remove the strain by annealing treatment. However, if the residual strain of the optical element produced by the precision press molding method is large, the shape dimension of the optical element is greatly changed by the annealing treatment. It is difficult to realize an optical element having a shape and dimension.

  In this way, reducing the residual strain when a glass molding is produced by a precision press molding method is common not only to glass molds but also to glass moldings in general.

  This invention is made | formed in view of the point which concerns, and the place made into the objective is to provide the shaping | molding die group which can manufacture the glass molded object with few distortions.

  The first mold set according to the present invention is for producing a glass molding by press molding a glass material. The mold set according to the present invention includes a columnar first mold, a columnar second mold, and a body mold. The second mold is disposed opposite to the first mold. The body mold is formed in a cylindrical shape so that the first mold and the second mold are slidably inserted. The linear thermal expansion coefficient of the body mold is less than or equal to the linear thermal expansion coefficient of the glass material to be press-formed.

  In this specification, “linear thermal expansion coefficient” refers to a linear thermal expansion coefficient measured at 100 ° C. to 300 ° C. The linear thermal expansion coefficient can be measured by, for example, a thermomechanical analyzer manufactured by Rigaku Corporation.

  The 2nd shaping | molding die group which concerns on this invention is for manufacturing a glass molded object by press-molding a glass material. The mold set according to the present invention includes a columnar first mold, a columnar second mold, and a body mold. A convex molding surface is formed on the top surface of the first mold. The second mold is disposed opposite to the molding surface. The body mold is formed in a cylindrical shape so that the first mold and the second mold are slidably inserted. The linear thermal expansion coefficient of the first mold is not less than the linear thermal expansion coefficient of the glass material to be press-molded.

  The 3rd shaping | molding die group which concerns on this invention is for manufacturing a glass molded object by press-molding a glass material. The mold set according to the present invention includes a columnar first mold, a columnar second mold, and a body mold. A concave molding surface is formed on the top surface of the first molding die. The second mold is disposed opposite to the molding surface. The body mold is formed in a cylindrical shape so that the first mold and the second mold are slidably inserted. The linear thermal expansion coefficient of the first mold is not more than the linear thermal expansion coefficient of the glass material to be press-molded.

  By using the mold set according to the present invention, it is possible to produce a glass molding with less distortion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a manufacturing apparatus 1 according to the first embodiment.

  The manufacturing apparatus 1 according to the first embodiment includes an upper press board 2 in which a plurality of heaters 4 are embedded, a lower press board 3 in which a plurality of heaters 4 are embedded, and between the upper press board 2 and the lower press board 3. And a mold set 10 disposed on the surface. The upper press board 2 is connected to a press (not shown) (for example, an air cylinder, a servo motor, etc.), and the upper press board 2 is configured to be relatively displaceable with respect to the lower press board 3.

  The mold set 10 includes an upper mold 11, a lower mold 12, and a cylindrical body mold 13.

  The upper mold 11 is formed in a cylindrical shape. Specifically, the upper mold 11 includes a columnar main body and a flange portion provided on the base end side of the main body. A convex molding surface is formed on the top surface of the upper mold 11. On the molding surface, a release film 11a for improving the release property of the glass material 14 to be molded is formed. The release film 11a can be formed of, for example, Pt, Ir, SiC, Ti / Pt—Ir, or the like.

  The upper die 11 has an outer diameter that is substantially the same as the inner diameter of the barrel die 13 so that the upper die 11 can be slidably inserted into the cylindrical barrel die 13 (specifically, slightly more than the inner diameter of the barrel die 13). Only small).

  The lower die 12 is disposed on the lower press board 3 so as to face the upper die 11. The lower mold 12 is formed in a cylindrical shape. Specifically, the lower mold 12 includes a cylindrical main body and a flange portion provided on the base end side of the main body. A flat molding surface is formed on the top surface of the lower mold 12. On the molding surface, a release film 12a for improving the mold release property of the glass material 14 to be molded is formed. The release film 12a can be formed of, for example, Pt, Ir, SiC, Ti / Pt—Ir, etc., like the release film 11a. The release film 11a and the release film 12a may be formed of the same material, or may be formed of different materials.

  The lower die 12 has an outer diameter that is substantially the same as the inner diameter of the barrel die 13 so that the lower die 12 can be slidably inserted into the cylindrical barrel die 13 (specifically, slightly smaller than the inner diameter of the barrel die 13). Only small).

  Next, the shaping | molding of the glass material 14 using the manufacturing apparatus 1 is demonstrated in detail.

  First, the glass material 14 is inserted into the internal space defined by the upper mold 11 and the lower mold 12 in the body mold 13. Next, the mold set 10 and the glass material 14 charged in the mold set 10 are heated using the heaters 4 embedded in each of the upper press board 2 and the lower press board 3. In that case, it is preferable that the upper press board 2 is disposed close to the upper mold 11. Specifically, it is preferable that the upper press platen 2 is arranged to be separated from the upper die 11 by 0.1 mm or more and 5 mm or less (more preferably, 0.1 mm or more and 1 mm or less, for example, 0.5 mm). By bringing the upper press panel 2 appropriately close to the upper mold 11, temperature unevenness generated in the mold set 10 can be reduced. In addition, it is preferable to perform a heating until the temperature of the glass material 14 becomes the yield point (softening temperature) vicinity, for example.

  Next, the glass material 14 is press-molded by displacing the upper die 11 together with the upper press disk 2 in the direction of the lower die 12 (downward in FIG. 1) using a press (not shown). The press molding is preferably performed under conditions (temperature, pressure, pressing time) such that the molding surface of the upper mold 11 is transferred to the glass material 14. These conditions can be appropriately determined based on the material of the glass material 14 (glass transition temperature, softening temperature, linear thermal expansion coefficient, etc.), the shape of the molding surface of the upper mold 11, and the like.

  After the press molding is completed, the output of the heater 4 is reduced (or the power of the heater 4 is turned off), and the glass material 14 molded in the mold set 10 is cooled to a predetermined temperature. The cooling speed at this time is preferably slow from the viewpoint of reducing the temperature unevenness inside the glass material 14 in the cooling step and reducing the distortion remaining in the molded glass material 14. On the other hand, a higher cooling speed is preferable from the viewpoint of throughput. For this reason, it is preferable to determine the cooling speed after considering both the amount of allowable distortion and the viewpoint of throughput.

  The mold set 10 and the molded glass material 14 shrink as they are cooled. The amount of shrinkage per unit temperature depends on the linear thermal expansion coefficient (α) of the mold set 10 and the glass material 14. Specifically, the amount of shrinkage per unit temperature increases as the linear thermal expansion coefficient increases.

  For example, when the linear thermal expansion coefficient of the barrel mold 13 is larger than the linear thermal expansion coefficient of the glass material 14, the thermal shrinkage amount per unit temperature of the barrel mold 13 is larger than the thermal shrinkage amount per unit temperature of the glass material 14. Get smaller. For this reason, the glass material 14 is shrink-fitted by the body mold 13 in the cooling step. That is, the glass material 14 is cooled while being pressed by the body mold 13. Therefore, a large strain remains in the cooled glass material 14.

  However, in the first embodiment, the linear thermal expansion coefficient of the body mold 13 is set to be equal to or less than the linear thermal expansion coefficient of the glass material 14. For this reason, in the first embodiment, the amount of heat shrinkage per unit temperature of the body mold 13 is equal to or less than the amount of heat shrinkage per unit temperature of the glass material 14. Accordingly, since the glass material 14 is not pressed by the body mold 13 in the cooling step, the distortion remaining in the formed glass material 14 can be reduced.

  In the first embodiment in which the molding surface of the upper mold 11 is formed in a convex shape, the linear thermal expansion coefficient of the upper mold 11 is set to be greater than or equal to the linear thermal expansion coefficient of the glass material 14.

  FIG. 2 is a diagram schematically illustrating the thermal contraction of the upper mold 11 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 11 is smaller than the linear thermal expansion coefficient of the glass material 14.

  As shown in FIG. 2, when the linear thermal expansion coefficient of the upper mold 11 is smaller than the linear thermal expansion coefficient of the glass material 14, the thermal contraction amount of the upper mold 11 is smaller than the thermal contraction amount of the glass material 14. For this reason, the glass material 14 is cooled while being pressed by the upper mold 11. Therefore, a large strain remains in the cooled glass material 14.

  FIG. 3 is a diagram schematically illustrating the thermal contraction of the upper mold 11 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 11 is equal to or higher than the linear thermal expansion coefficient of the glass material 14.

  As shown in FIG. 3, when the linear thermal expansion coefficient of the upper mold 11 is greater than or equal to the linear thermal expansion coefficient of the glass material 14, the thermal shrinkage amount of the upper mold 11 is greater than or equal to the thermal contraction amount of the glass material 14. Accordingly, since the glass material 14 is not pressed by the upper mold 11 in the cooling step, it is possible to reduce distortion remaining in the formed glass material 14.

  As described above, the linear thermal expansion coefficient of the body mold 13 is set to be equal to or less than the linear thermal expansion coefficient of the glass material 14 and / or the linear thermal expansion coefficient of the upper mold 11 having a convex molding surface is set to the glass material. By setting the linear thermal expansion coefficient to 14 or more, it is possible to obtain a glass molded article with little residual distortion.

  For example, when a glass mold for molding a glass optical element is formed using the mold set 10 according to the first embodiment, the resulting glass mold is less distorted. For this reason, even if this glass shaping | molding die repeats the shaping | molding process of a glass optical element, a shape dimension does not change easily with time and manufacture of the stable glass optical element is attained. That is, by using the mold set 10 according to the first embodiment, for example, a glass mold that can stably manufacture a glass optical element can be manufactured. In the case of molding a glass mold, the glass material 14 preferably has a glass transition temperature higher than the glass transition temperature of the glass optical element that is scheduled to be molded.

  In addition, from the viewpoint of obtaining a glass molding with less distortion, the glass material 14 molded using the mold set 10 may be further annealed (annealed). Specifically, after the glass material 14 is heated to a temperature in the vicinity of the glass transition temperature (Tg) (Tg-100 ° C. to Tg + 100 ° C.) and held for a predetermined time (several minutes to several hours), 5 ° C. per hour. You may cool about -200 degreeC at a time.

(Embodiment 2)
FIG. 4 is a cross-sectional view of the manufacturing apparatus according to the second embodiment.

  The second embodiment has the same configuration as that of the first embodiment except for the upper mold configuration. Here, the upper mold | type 21 in this Embodiment 2 is demonstrated in detail, referring drawings. In the second embodiment, components having substantially the same function will be described with reference numerals common to the first embodiment, and description thereof will be omitted.

  In the second embodiment, the mold set 20 includes an upper mold 21, a lower mold 12, and a body mold 13. The upper mold 21 has the same configuration as the upper mold 11 of the first embodiment except that it has a concave molding surface. A release film 21 a is formed on the top surface of the upper mold 21.

  In the second embodiment, the linear thermal expansion coefficient of the upper mold 21 is set to be equal to or lower than the linear thermal expansion coefficient of the glass material 14.

  FIG. 5 is a diagram schematically showing the state of thermal contraction of the upper mold 21 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 21 is larger than the linear thermal expansion coefficient of the glass material 14.

  As shown in FIG. 5, when the linear thermal expansion coefficient of the upper die 21 is larger than the linear thermal expansion coefficient of the glass material 14, the thermal shrinkage amount of the upper die 21 is larger than the thermal shrinkage amount of the glass material 14. For this reason, the glass material 14 is cooled while being pressed by the upper mold 21. Therefore, a large strain remains in the cooled glass material 14.

  FIG. 6 is a diagram schematically illustrating the thermal contraction of the upper mold 21 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 21 is equal to or less than the linear thermal expansion coefficient of the glass material 14.

  As shown in FIG. 6, when the linear thermal expansion coefficient of the upper mold 21 is equal to or less than the linear thermal expansion coefficient of the glass material 14, the thermal contraction amount of the upper mold 21 is equal to or less than the thermal contraction amount of the glass material 14. Accordingly, since the glass material 14 is not pressed by the upper mold 21 in the cooling step, it is possible to reduce distortion remaining in the formed glass material 14.

  As described above, the linear thermal expansion coefficient of the body mold 13 is set to be equal to or lower than the linear thermal expansion coefficient of the glass material 14 and / or the linear thermal expansion coefficient of the upper mold 21 having the concave molding surface is set to the glass material 14. By making the linear thermal expansion coefficient or less, a glass molded article with little residual strain can be obtained.

(Examples 1 and 2 and Reference Examples 1 to 3)
First, using the manufacturing apparatus 1 described in the first embodiment, glass molds 33 and 35 having a concave molding surface (punch diameter: 6 mm, curvature radius: 5 mm) on the top surface were molded. The molding temperature was set to 780 ° C., and after molding, the temperature was lowered to 400 ° C. over 3 hours, and then naturally cooled to room temperature. Thereafter, the obtained glass molds 33 and 35 were taken out.

In Example 1, borosilicate glass (glass transition temperature: 690 ° C., yield point: 740 ° C., linear thermal expansion coefficient: 54 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 60 × 10 ⁻⁷ / ° C.). The body die 13 was formed of a cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.).

In Example 2, borosilicate glass (glass transition temperature: 674 ° C., yield point: 724 ° C., linear thermal expansion coefficient: 47 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.). The body mold 13 was formed of silicon nitride (linear thermal expansion coefficient: 30 × 10 ⁻⁷ / ° C.).

In Reference Example 1, borosilicate glass (glass transition temperature: 689 ° C., yield point: 741 ° C., linear thermal expansion coefficient: 64 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 60 × 10 ⁻⁷ / ° C.). The body die 13 was formed of a cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.).

In Reference Example 2, borosilicate glass (glass transition temperature: 689 ° C., yield point: 741 ° C., linear thermal expansion coefficient: 64 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11, the lower mold 12 and the body mold 13 were all formed of cemented carbide (linear thermal expansion coefficient: 60 × 10 ⁻⁷ / ° C.).

In Reference Example 3, borosilicate glass (glass transition temperature: 689 ° C., yield point: 741 ° C., linear thermal expansion coefficient: 64 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11, the lower mold 12, and the body mold 13 were all formed of cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.).

  Next, release films 33a and 35a were formed on the glass molds 33 and 35, respectively. The release films 33a and 35a were formed by sputtering. Specifically, in Example 1 and Reference Examples 1 to 3, carbon 60 at. % Silicon carbide film was formed with a layer thickness of 0.4 μm. In Example 2, a laminate of a 0.1 μm thick Ti film and a 0.4 μm thick Ir—Pt alloy film was formed.

  Thereafter, a glass optical element (convex lens) 38 was formed using a manufacturing apparatus 30 provided with glass molds 33 and 35.

  FIG. 7 is a sectional view of the manufacturing apparatus 30 (before forming the optical element 38) used for forming the optical element 38. FIG.

  FIG. 8 is a cross-sectional view of the manufacturing apparatus 30 (after the optical element 38 is formed) used for forming the optical element 38.

  As shown in FIG. 7, the manufacturing apparatus 30 includes an upper press board 31 and a lower press board 36 in which a heater 32 is embedded. A mold set is arranged between the upper press board 31 and the lower press board 36. The mold set includes an upper mold 33 and a lower mold 35 manufactured in the above-described process, and a cylindrical body mold 34 into which the upper mold 33 and the lower mold 35 are slidably inserted.

  The manufacturing apparatus 30 was charged with a glass material 37 as a material for the optical element 38, and press-molded 100 times. Specifically, the upper press platen 31 and the lower press platen 36 which are arranged at a distance of 0.5 mm from the upper die 33 were each heated to 600 ° C. and held for 30 seconds. Then, press molding was performed by pressing the upper press board 31 with 50 kgf. As the glass material 37, K-PBK40 (glass transition temperature: 501 ° C., yield point: 549 ° C.) manufactured by Sumita Optical Glass Co., Ltd. was used.

  FIG. 9 is a diagram for explaining a method for evaluating the shape of the molding surface of the lower die 35. In FIG. 9, the shape of the molding surface after molding is indicated by a solid line, and the shape of the molding surface before molding is indicated by a broken line.

  Thereafter, the shape of the molding surface of the lower die 35 before being used for press molding was compared with the shape of the molding surface of the lower die 35 after being used for press molding. Specifically, as shown in FIG. 9, the shape evaluation of the molding surface of the lower die 35 is performed after molding at a location 2 mm away from the center of the molding surface in a state where the lowest point of the molding surface is matched. The difference in height (change amount: Δ) between the surface and the molding surface before molding was measured. When the change Δ was 0.2 μm or less, it was evaluated as “◯”, and when it was larger than 0.2 μm, it was evaluated as “x”. In addition, the shape measurement was performed using Matsushita Electric Industrial Co., Ltd. UA3P.

(Examples 3 and 4 and Reference Examples 4 and 5)
First, using the manufacturing apparatus 1 described in the first embodiment, glass molds 33 and 35 having a convex molding surface (punch diameter: 6 mm, curvature radius: 5 mm) on the top surface were molded. The molding temperature was set to 780 ° C., and after molding, the temperature was lowered to 400 ° C. over 3 hours, and then naturally cooled to room temperature. Thereafter, the obtained glass molds 33 and 35 were taken out.

In Example 3, borosilicate glass (glass transition temperature: 679 ° C., yield point: 724 ° C., linear thermal expansion coefficient: 56 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11, the lower mold 12, and the body mold 13 were all formed of cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.).

In Example 4, borosilicate glass (glass transition temperature: 689 ° C., yield point: 741 ° C., linear thermal expansion coefficient: 64 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.). The body mold 13 was formed from a cemented carbide (linear thermal expansion coefficient: 60 × 10 ⁻⁷ / ° C.).

In Reference Example 4, borosilicate glass (glass transition temperature: 679 ° C., yield point: 724 ° C., linear thermal expansion coefficient: 56 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 60 × 10 ⁻⁷ / ° C.). The body die 13 was formed of a cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.).

In Reference Example 5, borosilicate glass (glass transition temperature: 674 ° C., yield point: 724 ° C., linear thermal expansion coefficient: 47 × 10 ⁻⁷ / ° C.) was used as the glass material 14. The upper mold 11 and the lower mold 12 were formed of cemented carbide (linear thermal expansion coefficient: 50 × 10 ⁻⁷ / ° C.). The body mold 13 was formed of silicon nitride (linear thermal expansion coefficient: 30 × 10 ⁻⁷ / ° C.).

  Next, carbon 60 at. Release films 33a and 35a made of a 50% silicon carbide film (film thickness 0.4 μm) were formed. The release films 33a and 35a were formed by sputtering.

  Thereafter, a glass optical element (concave lens) 38 is formed using the manufacturing apparatus 30 under the same materials and conditions as in Example 1, and the shape of the molding surface of the lower mold 35 and press molding before being used for press molding. The shape of the molding surface of the lower mold 35 after being used for the comparison was measured.

  The results of Examples 1 to 4 and Reference Examples 1 to 5 are shown in Table 1 below.

  As shown in Table 1, in the case of a molding die 35 having a concave molding surface for forming a convex lens, the linear thermal expansion coefficient of the body mold 13 is smaller than the linear thermal expansion coefficient of the glass material 14 and the upper mold 11 is used. It was found that the shape change was relatively small when the linear thermal expansion coefficient was greater than the linear thermal expansion coefficient of the glass material 14. That is, it was found that the amount of strain remaining in the glass molds 33 and 35 was small.

  Further, in the case of the molding die 35 having a convex molding surface for forming a concave lens, the linear thermal expansion coefficient of the body mold 13 is smaller than the linear thermal expansion coefficient of the glass material 14 and the linear thermal expansion of the upper mold 11. It was found that the shape change was relatively small when the coefficient was smaller than the linear thermal expansion coefficient of the glass material 14. That is, it was found that the amount of strain remaining in the glass molds 33 and 35 was small.

  Furthermore, the glass molds 33 in Examples 1 to 4 and Reference Examples 1 to 5 prepared by the same method as described above were annealed except that the glass mold was cooled to 400 ° C. in 30 minutes. Specifically, it was held at 650 ° C. for 8 hours, and then cooled to room temperature at 120 ° C./hour. And the shape change of the molding surface before annealing treatment and after annealing treatment was confirmed. As a result, in Examples 1 to 4, the shape change was relatively small, and in Reference Examples 1 to 5, the shape change was relatively large.

  As a result, in the case of the molding die 35 having a concave molding surface for forming a convex lens, the residual strain can be reduced when the linear thermal expansion coefficient of the upper mold 11 is larger than the linear thermal expansion coefficient of the glass material 14, Further, in the case of the molding die 35 having a convex molding surface for forming a concave lens, it is supported that the residual strain can be reduced when the linear thermal expansion coefficient of the upper mold 11 is smaller than the linear thermal expansion coefficient of the glass material 14. is doing.

  As described above, since a glass molding with less distortion can be produced by using the mold set according to the present invention, glass molding for molding optical elements such as lenses and prisms, and glass elements. Useful for manufacturing molds.

1 is a cross-sectional view of a manufacturing apparatus 1 according to Embodiment 1. FIG. FIG. 5 is a diagram schematically showing the state of thermal contraction of the upper mold 11 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 11 is smaller than the linear thermal expansion coefficient of the glass material 14. It is the figure which represented typically the mode of the thermal contraction of the upper mold | type 11 and the glass material 14 in case the linear thermal expansion coefficient of the upper mold | type 11 is more than the linear thermal expansion coefficient of the glass material 14. FIG. It is sectional drawing of the manufacturing apparatus which concerns on Embodiment 2. FIG. FIG. 5 is a diagram schematically illustrating the state of thermal contraction of the upper mold 21 and the glass material 14 when the linear thermal expansion coefficient of the upper mold 21 is larger than the linear thermal expansion coefficient of the glass material 14. It is the figure which represented typically the mode of the thermal contraction of the upper mold | type 21 and the glass material 14 in case the linear thermal expansion coefficient of the upper mold | type 21 is below the linear thermal expansion coefficient of the glass material 14. FIG. It is sectional drawing of the manufacturing apparatus 30 (before formation of the optical element 38) used for formation of the optical element 38. FIG. It is sectional drawing of the manufacturing apparatus 30 (after formation of the optical element 38) used for formation of the optical element 38. FIG. It is a figure for demonstrating the shape evaluation method of the molding surface of the lower mold | type 35. FIG.

Explanation of symbols

1, 30 Production equipment
2, 31 Upper press board
3, 36 Lower press panel
4, 32 heater
10, 20 Mold set
11, 21, 33 Upper mold
11a, 12a, 21a, 33a, 35a Release film
12, 35 Lower mold
13, 34 trunk type
14, 37 Glass material
38 Optical elements

Claims (8)

A mold set for producing a glass molding by press molding a glass material,
A columnar first mold,
A columnar second mold placed opposite to the first mold;
A cylindrical body mold into which the first mold and the second mold are slidably inserted;
With
The barrel mold is a mold set whose linear thermal expansion coefficient is equal to or less than the linear thermal expansion coefficient of the glass material to be press-molded. In the mold set according to claim 1,
The first molding die has a convex molding surface formed on the top surface facing the second molding die, and the linear thermal expansion coefficient of the glass material wire to be press-molded. Mold set that has a thermal expansion coefficient or higher. In the mold set according to claim 1,
The first molding die has a concave molding surface formed on the top surface facing the second molding die, and the linear thermal expansion coefficient thereof is the linear heat of the glass material to be press-molded. A mold set that has an expansion coefficient or less. A mold set for producing a glass molding by press molding a glass material,
A columnar first molding die having a convex molding surface formed on the top surface;
A columnar second mold placed opposite to the molding surface;
A cylindrical body mold into which the first mold and the second mold are slidably inserted;
With
Said 1st shaping | molding die is a shaping die group whose linear thermal expansion coefficient is more than the linear thermal expansion coefficient of the glass material by which press molding is carried out. A mold set for producing a glass molding by press molding a glass material,
A columnar first molding die having a concave molding surface formed on the top surface;
A columnar second mold placed opposite to the molding surface;
A cylindrical body mold into which the first mold and the second mold are slidably inserted;
With
Said 1st shaping | molding die is a shaping die group whose linear thermal expansion coefficient is below the linear thermal expansion coefficient of the glass material press-molded. In the mold set according to claim 4 or 5,
The barrel mold is a mold set whose linear thermal expansion coefficient is equal to or less than the linear thermal expansion coefficient of the glass material to be press-molded. In the mold set according to claim 1, 4, or 5,
The glass molding is a mold set that is a mold for molding a glass optical element. In the mold set according to claim 7,
The glass molding is a mold set whose glass transition temperature is higher than the glass transition temperature of the optical element.

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