JP2005001917A - Mold press-forming apparatus and method of manufacturing optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the eccentric precision of an optical device by preventing the thermal deformation of a supporting member supporting a plurality of mother dies. <P>SOLUTION: The mold press forming apparatus has top and bottom forming dies opposed to each other and a heating means for heating the top and bottom forming dies. The apparatus is composed of a plurality of pairs of top and bottom mother dies 102a, 102b, 104a and 104b provided with at least the pair of top and bottom forming dies, a plurality of pairs of the top and the bottom press shafts 110 and 112 respectively supporting a plurality of the top and bottom mother dies, top and bottom supporting members 114 and 116 for supporting the plurality of pairs of the top and bottom press shafts, a driving means for moving at least one of the top and bottom supporting members to be relatively close to or apart from the top and bottom forming dies each other and a temperature controlling means by a cooling water passages 116a and 116b provided at least one of the top and bottom supporting members. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

［比較例１］
実施例と同様の方法で、支持部材の調温を行わずに、６個のレンズを同時成形した。結果は、６個のレンズの肉厚差が最大７０μｍあり、また成形偏心ティルトは、５分以下だった。
【表２】

【００３８】
【発明の効果】
以上のように、本発明によれば、支持部材の調温を行うことによって支持部材の熱変形を防ぐことができるので、支持部材の変形に起因する肉厚精度及び偏心精度の悪化を防止することができる。
【図面の簡単な説明】
【図１】図１は、本発明の一実施形態にかかるモールドプレス成形装置の要部構造を示す一部断面側面図であり、（ａ）はプリフォームの供給状態を示し、（ｂ）は加圧状態を示し、（ｃ）は離型状態を示す。
【図２】図２は、図１における型の概略平面図である。
【図３】図３は、図１に示す支持部材の概略平面断面図である。
【図４】図４は、母型の熱変形（反り）を示す図である。
【図５】図５は、モールドプレス成形装置における支持部材が熱変形をしている状態の要部構造を示す側面図であり、（ａ）はプリフォームの供給状態を示し、（ｂ）は加圧状態を示し、（ｃ）は離型状態を示す。
【符号の説明】
１０２ 上型
１０２ａ，１０２ｂ 上母型
１０４ 下型
１０４ａ，１０４ｂ 下母型
１０５ａ 上成形型
１０５ｂ 下成形型
１０６ａ 上支持板
１０６ｂ 下支持板
１１０ａ，１１０ｂ 上プレス軸
１１２ａ，１１２ｂ 下プレス軸
１１４ 上支持部材
１１６ 下支持部材
１１６ａ 水路
１１６ｂ 連水路
１１８ 固定軸（主軸）
１２０ 駆動軸（主軸）
１２１ａ 導水路
１２１ｂ 還水路
１２２，１２４ 高周波誘導コイル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold press molding apparatus and an optical element for heating and softening a molding material (preliminarily preformed preform or the like) in a manufacturing process of an optical element or the like, and press molding with a molding die to mold the optical element or the like. It relates to the manufacturing method.
[0002]
[Prior art]
A molding material in a heat-softened state, for example, a glass material, is press-molded in a mold that is precisely processed into a predetermined shape and heated to a predetermined temperature, and the molding surface is transferred to the glass material. An optical element with high surface accuracy and shape accuracy can be obtained without processing.
In this case, in order to efficiently produce an optical element (for example, a lens), a device is known in which a plurality of molding dies are arranged on a mother die and a plurality of lenses are molded by a single press operation.
[0003]
When a plurality of molding materials are press-molded at once using such a molding apparatus, for example, if the molding die is heated by heating means such as an induction heating coil, a temperature difference is generated between the upper and lower surfaces of the mother die, and the mother The mold may be warped as shown in FIG. This is because it is difficult to make the temperature of the entire mother mold uniform because heat is dissipated from a press shaft or the like that supports the mother mold.
In particular, when a plurality of forming dies are arranged on the mother die and a plurality of simultaneous pressings are performed, the influence of the warp of the mother die is great. For this reason, the thickness of the optical element to be molded varies depending on the position of the mold on the mother die, or the upper and lower coaxiality is impaired, and the eccentricity accuracy (tilt) deteriorates. This problem is more serious as the number of molds arranged on the mother die is larger or the diameter of the optical element to be molded is larger.
[0004]
Therefore, when performing multiple simultaneous presses, in order to keep the size of the matrix in the horizontal direction below a certain level, the matrix is divided into a plurality of molds, and the plurality of molds are fixed to a single support member by a plurality of press shafts. The applicant has proposed a molding apparatus that drives it by a single spindle (for example, Patent Document 1). According to this molding apparatus, the influence of warpage can be reduced while maintaining the number of optical elements that can be pressed simultaneously.
[0005]
[Patent Document 1]
JP 2003-54967 A
[0006]
[Problems to be solved by the invention]
Thus, according to the molding apparatus described in Patent Document 1, it is possible to perform press molding with a certain degree of eccentricity accuracy. However, the accuracy required for optical elements becomes higher and higher. For example, in an objective lens for an optical pickup, the tolerance of decentering accuracy becomes narrower as the recording density increases. The eccentricity accuracy of the product to be obtained may not be sufficient.
[0007]
Therefore, in order to further improve the eccentric accuracy, the present inventors have pursued a factor that has an adverse effect on the eccentric accuracy, the thermal deformation also slightly occurs in the support member that supports the plurality of press shafts, It has been found that this phenomenon has an adverse effect on the lens thickness accuracy and eccentricity accuracy.
That is, in the press molding apparatus, before the temperature is raised by the heating means, as shown in FIG. 5A, the opposing surfaces of the upper mother molds 102a and 102b and the lower mother molds 104a and 104b are in a horizontal state. The axes of the upper and lower molds coincide with each other. However, when the mother mold is heated to a temperature suitable for press molding and becomes hot (depending on the molding material, it may be 600 ° C. or higher), the upper and lower support members 114 and 116 are heated by heat conduction and heat radiation. As shown in FIG. 5B, the plurality of press shafts that support the plurality of mother dies are slightly inclined with respect to the main axis, and the axes of the upper and lower surfaces of the press-molded lens are inclined. It has been found that this is a cause of deteriorating the thickness accuracy and eccentricity accuracy of the lens.
Therefore, it has been found that the wall thickness accuracy and the eccentricity accuracy can be further improved by suppressing the inclination of the press shaft.
[0008]
The present invention has been made in view of the above circumstances, and even an optical element having a very small tolerance of eccentricity accuracy can be stably produced by press molding, and a non-isothermal press with a reduced cycle time is used. Another object of the present invention is to provide a mold press molding apparatus and an optical element manufacturing method capable of stably producing a plurality of elements with high-accuracy thickness at the same time.
[0009]
[Means for Solving the Problems]
To achieve the above object, the mold press molding apparatus of the present invention is a mold press molding apparatus having opposed upper and lower molding dies and heating means for heating the upper and lower molding dies, each of which is at least a pair of the upper and lower moldings. A plurality of pairs of upper and lower mother dies provided with a mold, a plurality of pairs of upper and lower press shafts that respectively support the plurality of pairs of upper and lower mother dies, a vertical support member that supports these pairs of upper and lower press shafts, and the upper and lower molding dies However, the driving means for moving at least one of the upper and lower support members so as to relatively approach and separate from each other and the temperature control means provided on at least one of the upper and lower support members are provided.
[0010]
With such a configuration, the temperature of the support member can be adjusted to prevent thermal deformation of the support member, thereby preventing a decrease in the eccentric accuracy of the molding element due to the thermal deformation of the support member. .
[0011]
Moreover, this invention is set as the structure which provided the said temperature control means in the inside and / or the outside of the said supporting member.
With such a configuration, the temperature can be adjusted from the inside and / or the outside of the support member, so that thermal deformation of the support member can be effectively prevented. In particular, adjusting the temperature inside the support member is preferable because the temperature difference between the inside and outside of the support member can be reduced.
[0012]
In the present invention, the temperature adjusting means is constituted by a cooling means.
With such a configuration, the temperature distribution of the support member can be accurately adjusted in a short time, and thermal deformation can be efficiently prevented.
[0013]
In the present invention, a thermal resistor having a thermal resistance value of 1 K / W or more is interposed between at least one of the upper and lower support members and the upper and lower matrixes.
With such a configuration, heat transfer from the mother die to the support member can be suppressed, so that the eccentric accuracy of the molding element can be further improved in combination with temperature control on the support member.
[0014]
In order to achieve the above object, the optical element manufacturing method of the present invention uses a mold press molding apparatus to manufacture the optical element by a method including a mold heating step, a material supply step, and a pressure step. Among the processes, the temperature of the support member is adjusted at least in the mold heating process.
In this way, at least in the mold heating process in which the mother mold is heated to a high temperature, if the temperature of the support member is adjusted, thermal deformation of the support member can be effectively prevented, and consequently the eccentricity accuracy of the optical element can be reduced. Improvement and uniformity can be achieved.
[0015]
In addition, the present invention is a method for maintaining the temperature distribution on the surface of the support member on the side of supporting the press shaft at 5 ° C. or less, preferably 2 ° C. or less by the temperature control.
As described above, when the temperature distribution on the surface of the support member on the side where the press shaft is supported is maintained at 5 ° C. or less, preferably 2 ° C. or less, it is possible to suppress the occurrence of heat accumulation near the central axis on the horizontal plane. Can be reliably prevented.
[0016]
Further, the present invention is a method in which a plurality of heated upper and lower molds are simultaneously supplied with a molding material heated and softened to a temperature higher than that of the upper and lower molds, and simultaneously pressed by the upper and lower molds.
In this way, a highly accurate and uniform optical element can be manufactured in a short time.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following, the present invention will be described in accordance with an embodiment in which the present invention is applied to the production of a glass optical element. However, the mold press molding apparatus of the present invention is not limited to this embodiment, and a resin optical element is produced. Alternatively, it can be applied to the manufacture of parts other than glass and resin optical elements.
[0018]
FIG. 1 is a partial cross-sectional side view showing a main structure of a press molding apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic plan view of a lower mold. This press molding apparatus molds a lens using a preform as a molded body in which a glass material is previously molded into a flat spherical shape. As shown in FIG. 1, the press molding apparatus includes a mold set including an upper mold 102 and a lower mold 104. Each of the upper mold 102 and the lower mold 104 has a long shape that is long in the left-right direction, and induction heating coils 122 and 124 are respectively provided around the upper mold 102 and the lower mold 104. These induction heating coils 122 and 124 heat the upper mold 102 and the lower mold 104, respectively, by high frequency induction heating.
[0019]
The upper mold 102 has upper mother molds 102a and 102b which are a pair of left and right mother molds, and the lower mold 104 has lower mother molds 104a and 104b which are a pair of left and right mother molds. The upper mother molds 102a and 102b and the lower mother molds 104a and 104b respectively include a plurality of (three in the present embodiment) upper mold 105a and lower mold 105b that face each other in the vertical direction (FIG. 2). reference).
The materials of the upper and lower mother dies 102a, 102b, 104a, 104b generate heat by induction heating and use heat-resistant heating elements. As the heating element, it is preferable to use a material having a coefficient of thermal expansion close to that of the molds 105a and 105b. For example, a tungsten alloy or a nickel alloy can be used.
Positioning members such as pins and sleeves are preferably provided on the opposing surfaces of the upper mother molds 102a and 102b and the lower mother molds 104a and 104b for positioning when the upper and lower molds 105a and 105b are closed.
[0020]
Further, for example, ceramics such as silicon carbide and silicon nitride, cemented carbide or the like can be used for the upper and lower molding dies 105a and 105b arranged in a row.
The molding surfaces of the upper and lower molding dies 105a and 105b are preferably precisely processed into the shape of the optical element to be molded, and a release film is preferably provided in order to improve the mold release property. As the release film, a film mainly composed of noble metals (Pt, Ir, Au, etc.) or carbon can be applied.
[0021]
Support plates 106a and 106b are respectively fixed to the upper surfaces of the upper master dies 102a and 102b, and upper press shafts 110a and 110b are respectively attached to the upper surfaces of the support plates 106a and 106b. The upper press shafts 110 a and 110 b are attached to the fixed shaft 118 via a common support member 114. On the other hand, support plates 108a and 108b are respectively fixed to the lower surfaces of the lower master dies 104a and 104b, and lower press shafts 112a and 112b are respectively attached to the lower surfaces of the support plates 108a and 108b. The lower press shafts 112 a and 112 b are attached to the drive shaft 120 via a common support member 116. The drive shaft 120 is linearly driven in the vertical direction by a drive device having an AC servo motor, and its axis coincides with the longitudinal center of the upper mold 102 and the lower mold 104. When the drive shaft 120 moves in the vertical direction, the upper mold 102 and the lower mold 104 are opened and closed. A drive means is constituted by the drive shaft 120 and the drive device.
The axes of the fixed shaft 118 and the drive shaft 120 are parallel to the perpendicular to the opposing surfaces of the upper and lower mother dies.
In this embodiment, the upper mold is fixed and the lower mold is moved up and down, but the lower mold may be fixed and the upper mold moved up and down, and the upper and lower molds are moved up and down. You may make it move.
[0022]
As described above, the upper mother dies 102a and 102b and the lower mother dies 104a and 104b are fixed to the upper and lower press shafts 110 and 112 via the upper and lower support plates 106a and 106b. Therefore, by selecting a shape and a material that do not easily transmit heat as the upper and lower press shafts 110 and 112 and the upper and lower support plates 106a and 106b, it is possible to suppress the spread of heat to the support member. In addition, it is preferable to use thermal resistors for the upper and lower press shafts 110 and 112 and the upper and lower support plates 106a and 106b because heat transfer can be further suppressed. Here, the thermal resistor means one having a thermal resistance of 1 K / W (Kelvin / Watt) or more. For example, the above-described thermal resistor can be obtained by using a material having a low thermal conductivity or making a hollow shape to improve the shape. For example, Si ₃ N ₄ , ZrO ₂ If a hollow press shaft using a material such as is used, the spread of heat to the support member can be effectively suppressed, and thermal deformation of the support member can be suppressed. Where the thermal resistance is
R = d / (A · K).
R: thermal resistance, d: distance (length), A: area, K: thermal conductivity
[0023]
FIG. 2 is a plan view of the lower mold 104 (lower mother molds 104a and 104b) and the surrounding induction heating coil 124 as viewed from above. Since the planar shape of the upper mold 102 (upper mother molds 102a and 102b) is the same as that of the lower mold 104, the reference numerals corresponding to the upper mold are given in parentheses in the figure.
The induction heating coil 124 is wound in a shape following the outer periphery of the lower mother dies 104a and 104b so as to surround both of the lower mother dies 104a and 104b. The induction heating coil 122 provided around the upper mother molds 102a and 102b also has the same planar shape as the induction heating coil 124.
[0024]
The upper and lower support members 114 and 116 are preferably made of a material having excellent heat resistance and workability and excellent mechanical strength. The linear expansion coefficient is 18 × 10. ^-6 / ° C or less is preferred. Stainless steel or the like can be used as the material.
In addition, the size of the upper and lower support members 114 and 116 is required to have an area capable of fixing a plurality of press shafts, and the thickness is a support member calculated from the cross-sectional second moment and the Young's modulus where each press shaft is located. The amount of deflection is preferably 2 μm or less.
Here, the amount of deflection (δ) is
δ = βWL ³ / EI
(W: load, L: distance (distance between two press axes here), E: Young's modulus, I: sectional moment of inertia, β: deflection coefficient)
[0025]
The upper and lower support members 114 and 116 are provided with temperature control means. The temperature of the upper and lower support members 114 and 116 is adjusted by the heat of the upper and lower mother dies 102a, 102b, 104a, and 104b, which is heated by heating, by the press shafts 110a, 110b, 112a, and 112b, the support members 114 and 116, and the fixed shaft 118. , To adjust the non-uniform temperature distribution in the vertical direction of the support member that occurs when the drive shaft 120 is transmitted and escapes, so as to prevent the support member from causing non-uniform thermal expansion. Specifically, the temperature can be adjusted by circulating a cooling medium around the outer periphery and / or the inside of the upper and lower support members 114, 116.
[0026]
An example of the temperature control means formed on the lower support member 116 will be described with reference to FIG.
The temperature control means includes a water guide channel 121a for introducing cooling water from the outside to the drive shaft 120 fixed to the lower support member 116, a return water channel 121b for returning the cooling water to the outside, and a water channel formed inside the lower support member 116. 116a and a continuous water channel 116b. The water channel 116a formed inside the lower support member 116 is meandering on the upper surface side of the support member 116, and one end thereof communicates with the water conduit 121a and the other end communicates with the return water channel 121b. .
In this way, a constant temperature refrigerant (for example, cooling water) introduced from the water guide passage 121a is sent to the water passage 116a from substantially the center of the lower support member 116. After meandering and cooling, in the figure, it is sent from the left end to the right end via the continuous water channel 116b, and then the upper right side half of the lower support member 116 is meandered and cooled, and then the lower support member 116 is cooled. Is returned to the outside through the return water channel 121b.
In this case, it is preferable to use a cooling device equipped with a heat exchanger and circulate a coolant such as water, which is always kept at a constant temperature, to the lower support member 116.
[0027]
By providing such temperature control means, even if the lower matrix is heated, the temperature of the lower support member 116 does not exceed a certain level, and the local temperature difference of the support member can be reduced. The support member 116 is not deformed.
In addition to temperature control using a fluid, an electronic cooling device such as a Peltier element can also be used.
Since the temperature adjustment means is for balancing the temperature distribution in the support member, the temperature adjustment means may use a heating means or may be provided with a cooling means and a heating means.
Further, the temperature control means can be provided on the outer periphery of the lower support member 116, for example, a cooling water channel that winds the lower support member 116 is provided, or cold air is blown from the periphery of the lower support member 116. It may be the one.
Furthermore, temperature control means can be provided inside and outside the lower support member 116.
These temperature control means may be provided on the upper and lower support members or only on one of the support members. When the temperature control means is provided on the upper support member 114, the case of the lower support member 116 may be used. Similar temperature control means can be provided.
[0028]
Thus, in a mold press molding apparatus that supports each mother die by a press shaft and supports a plurality of press shafts by a single support member, the lens due to thermal deformation of the mother die is prevented by preventing thermal deformation of the support member. Suppresses uneven thickness or deterioration of eccentricity. Furthermore, since the support member is not placed at a high temperature unlike the mother die, it is supposed that there is no influence by thermal deformation. However, if the present invention is applied, further improvement in eccentricity accuracy can be achieved, and the optical A molding element (optical element) with higher performance can be stably produced with a higher yield.
[0029]
[Glass optical element manufacturing method]
An embodiment of a method for manufacturing a glass optical element according to the present invention using the glass optical element manufacturing apparatus having the above configuration will be described.
(A) Mold heating process
The upper and lower mother dies are heated to a predetermined temperature by a high frequency induction heating coil. In the case of continuous molding, the upper and lower molds in the state where the previous molding cycle has been completed are cooled to a temperature near or below Tg, and thus need to be heated to a temperature suitable for press molding. That is, an electric current is passed through an induction heating coil wound around the upper mother die and the lower mother die, the upper and lower mother dies are heated, and the upper and lower molding dies are heated to a predetermined temperature by this heat conduction.
[0030]
The upper and lower matrix heating elements generate heat and rise in temperature, and the temperature of the plurality of molds rises. The temperature setting values of the upper and lower matrixes may be the same in the upper and lower sides or may be provided with a temperature difference. For example, depending on the shape and diameter of the optical element to be molded, the lower mother die is set to a higher temperature than the upper mother die, or the lower mother die is set to a lower temperature than the upper mother die. The temperature of the upper and lower molds is 10 as the viscosity of the glass preform. ⁸ -10 ¹² It can be equivalent to Poise. In the case of providing a temperature difference between the upper and lower mother dies 411a and 411b, a range of 2 to 15 ° C. is preferable.
[0031]
(B) Material supply process
The conveyed preform (glass material) is supplied between the heated upper mold and lower mold, and is placed on the lower mold. The glass material is supplied by using a glass material that has been pre-formed into a predetermined shape with an appropriate weight and softened to a viscosity suitable for molding, or a glass material that is lower than the temperature suitable for molding. May be supplied between the upper mold and the lower mold and further heated in the mold.
In the case of heating to a temperature higher than the set temperature of the mold in advance and supplying a glass material in a softened state (so-called non-isothermal pressing) and immediately pressing the upper and lower molds in close contact, Since it is necessary that the coaxiality of the upper and lower molds forming a pair be maintained precisely, it is preferable to implement the present invention. The non-isothermal press can shorten the molding cycle time and is advantageous in terms of production efficiency.
The temperature of the glass material at this time is 10 in terms of viscosity. ⁹ The temperature is less than the equivalent of Poise, preferably 10 ⁶ ~ 18 ⁸ Equivalent to Pois.
When the softened glass material is transported and placed on the lower mold, if the glass material comes into contact with the transport member and a defect occurs on the surface, the surface shape of the optical element to be molded is affected. It is preferable to use a jig that conveys the glass material that has been floated by gas and drops the glass material onto the lower mold.
If necessary, insert a member (such as a chuck) between the upper and lower molds to correct the position on the lower mold where the glass preform to be supplied has dropped to the center of the molding surface. It is also possible to insert a member such as a funnel for guiding the material.
[0032]
(C) Pressurization process
The upper mold, the lower mold, and the glass material are each in a predetermined temperature range, and the glass material is heated and softened. A glass optical element having a shape is molded. The lower mold is raised by operating a driving means (for example, a servo motor). When the glass material is supplied in a heated and softened state, pressurization is performed immediately after the supply.
The ascending stroke of the lower mold for pressurization is a value set in advance from the thickness of the optical element to be molded, and is set to an amount that is determined in consideration of heat shrinkage of the glass in the subsequent cooling step. The pressurization schedule can be arbitrarily set according to the shape and size of the optical element to be molded. After initial pressurization, the load is released and then secondary pressurization is performed. A pressurizing method can also be employed.
[0033]
(D) Cooling / mold release process
While maintaining the pressure or reducing the pressure, the molded glass optical element and the mold are kept in close contact, and the viscosity of the glass is 10 ¹² After cooling to a temperature equivalent to Poise, the lower mold is moved downward to separate the upper and lower molds and release them. The cooling rate is preferably 40 to 200 ° C./min. The mold release temperature is 10 ^12.5 -10 ^13.5 It is preferable to carry out at or below Poise.
[0034]
(E) Removal process
A glass optical element molded from between the spaced apart upper and lower molds is automatically taken out by a take-out arm or the like equipped with an adsorbing member.
In this embodiment, the upper mold is fixed and the lower mold is movable, but the upper mold may be movable and the lower mold may be fixed, or both the upper mold and the lower mold may be movable.
[0035]
Continuous press molding is performed by repeating the above steps.
Among these, the temperature of the support member is adjusted at least in the step of heating the mold. Preferably, the temperature of the support member is adjusted in all steps of mold heating, material supply, and pressurization. By this temperature control, the temperature difference between the upper and lower surfaces of the support member is maintained at 5 ° C. or less, preferably 2 ° C. or less. The in-plane temperature difference between the upper surface and the lower surface of the support member is preferably within the same range.
In addition, you may adjust the flow volume of a refrigerant | coolant according to the timing of temperature fall and temperature rise during the thermal cycle of an apparatus.
[0036]
The optical element manufactured by the method of the present invention can be applied to, for example, a concave meniscus lens having a diameter of 2 to 22 mm, a convex meniscus lens, and a biconvex lens. Further, the tolerance of the eccentricity accuracy is extremely small (for example, tilt is 2 minutes or less), and the present invention can be effectively applied to an optical pickup objective lens.
[0037]
Next, the result of the Example which manufactured the glass optical element using the shaping | molding apparatus and manufacturing method of this invention, and a comparative example is shown.
[Example 1]
A glass material was press-molded using the apparatus shown in FIGS. Here, a forming apparatus that performs pressing using two master dies was prepared by providing a supporting member on one pressing main shaft and providing two pressing shafts on this supporting member. Three molds were set in each mother mold, and six lenses were molded at a time with six upper and lower molds housed in two upper and lower mother molds.
As the upper and lower support members used here, the cooling water circulation type temperature control means described in the present embodiment was used. And this temperature control means temperature-controlled in all the processes of heating, supply, and pressurization.
Using this molding machine, a concave meniscus lens having a diameter of 15 mm was molded using a glass preform of borosilicate glass (Tg 515 ° C., Ts 545 ° C.). Set the upper and lower molds at 590 ° C. ^8.1 625 ° C. (10 ⁷ Six glass preforms heated to the equivalent of Poise were dropped and supplied at the same time, and the upper and lower molds were brought into close contact with each other by driving the lower spindle upward and pressurized. Thereafter, the cooling was performed at a cooling rate of 60 ° C./min until the temperature reached Tg or less, the lower main shaft was driven downward to open the mold, and the molded lens was taken out.
Throughout the entire process, the temperature of the entire support member was adjusted to a range of 30 to 33 ° C. Further, as shown in the table below, the thickness difference of the six lenses molded at the same time was 10 μm or less, and the molding eccentric tilt was 2 minutes or less.
[Table 1]

[Comparative Example 1]
In the same manner as in the example, six lenses were simultaneously molded without adjusting the temperature of the support member. As a result, the maximum thickness difference of the six lenses was 70 μm, and the molding eccentric tilt was 5 minutes or less.
[Table 2]

[0038]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent thermal deformation of the support member by adjusting the temperature of the support member, thereby preventing deterioration in thickness accuracy and eccentricity accuracy due to deformation of the support member. be able to.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view showing the main structure of a mold press molding apparatus according to an embodiment of the present invention, (a) showing a preform supply state, and (b) A pressure state is shown, and (c) shows a release state.
FIG. 2 is a schematic plan view of the mold in FIG. 1;
FIG. 3 is a schematic plan sectional view of the support member shown in FIG. 1;
FIG. 4 is a diagram showing thermal deformation (warping) of a mother die.
FIG. 5 is a side view showing the main structure of a state in which a support member in a mold press molding apparatus is thermally deformed, (a) showing a preform supply state, (b) A pressure state is shown, and (c) shows a release state.
[Explanation of symbols]
102 Upper mold
102a, 102b Upper matrix
104 Lower mold
104a, 104b Lower matrix
105a Upper mold
105b Lower mold
106a Upper support plate
106b Lower support plate
110a, 110b Upper press shaft
112a, 112b Lower press shaft
114 Upper support member
116 Lower support member
116a waterway
116b continuous waterway
118 Fixed shaft (spindle)
120 Drive shaft (spindle)
121a Waterway
121b Return channel
122,124 high frequency induction coil

Claims (7)

In a mold press molding apparatus having opposing upper and lower molds and heating means for heating the upper and lower molds,
Each of a plurality of pairs of upper and lower molds each including at least a pair of the upper and lower molds,
A plurality of pairs of upper and lower press shafts that respectively support the plurality of pairs of upper and lower matrixes;
An upper and lower support member for supporting these multiple pairs of upper and lower press shafts;
Drive means for moving at least one of the upper and lower support members so that the upper and lower molds are relatively approaching and separating;
Temperature control means provided on at least one of the upper and lower support members,
A mold press molding apparatus characterized by comprising: The mold press molding apparatus according to claim 1, wherein the temperature control means is provided inside and / or outside the support member. The mold press molding apparatus according to claim 1 or 2, wherein the temperature control means is a cooling means. 4. A thermal resistor having a thermal resistance value of 1 K / W or more is interposed between at least one of the upper and lower support members and the upper and lower matrixes. Mold press molding equipment. When manufacturing an optical element by a method including a mold heating process, a material supply process, and a pressurization process using the mold press molding apparatus according to any one of claims 1 to 4, at least a mold among the above processes. A method of manufacturing an optical element, wherein the temperature of the support member is adjusted in the heating step. 6. The method of manufacturing an optical element according to claim 5, wherein the temperature distribution of the surface of the support member on the side supporting the press shaft is maintained at 5 [deg.] C. or less. 7. A plurality of heated upper and lower molds are simultaneously supplied with a molding material heated and softened to a temperature higher than that of the upper and lower molds, and simultaneously pressed by the upper and lower molds. The manufacturing method of the optical element of description.

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