JP4711697B2 - Optical element manufacturing method, mold press molding apparatus, and positioning apparatus used therefor - Google Patents

Description

  The present invention provides a method for manufacturing an optical element, a mold press molding apparatus, which press-molds a molding material such as glass by a molding die subjected to precision processing without requiring post-processing such as grinding or polishing of a surface to be molded, And a positioning device used for these.

  There is known a method of manufacturing an optical element such as a lens by press-molding a molding material such as glass by heating with a pair of upper and lower molding dies softened by heating and precisely processed into a predetermined shape (for example, Patent Document 1). To 3).

  Here, in Patent Document 1, an optical material (molding material) is molded by using a rack and a pinion in the mold, moving a pair of positioning members, and abutting the optical material between them. Is described.

  Patent Document 2 discloses that an optical element material is housed in an element material housing recess provided on the element material setting member and having substantially the same diameter as the optical element material (molding material), and the lower die is sucked while sucking the optical element material A set method is disclosed in which an optical element material is placed at the center of a mold for molding an optical element by being conveyed upward.

  Patent Document 3 discloses a device that positions the material center of an optical material (molding material) at the center position of the optical material placement location. The positioning device disclosed in Patent Document 3 vibrates a reference member that causes an end of a moving member that moves in a positioning direction to abut on an outer peripheral portion of an optical material with respect to an optical element placed on the reference member. Alternatively, the optical material is positioned by bringing the moving member into contact with the disk surface of the optical material by a bell clamp method.

Japanese Patent No. 3501580 Japanese Patent No. 3222548 JP 10-29826 A

When molding a molding material such as glass with a precision mold press and molding an optical element such as a lens, the molding material is generally pressed and molded between a pair of upper and lower molds having opposing molding surfaces. Has been done.
In such a molding method, it is necessary to supply and arrange a molding material at the center position of the lower mold molding surface in advance, and the molding material is not arranged at the center position of the lower mold molding surface, and is unevenly distributed on the molding surface. If this is done, the optical element to be molded will become uneven, resulting in poor shape, as well as uneven application of the press load due to the uneven thickness, resulting in improved surface accuracy of the optical functional surface. It will deteriorate.
However, depending on the shape of the optical element to be obtained and the structure of the mold used for press molding, it is not always easy to place the molding material at the center position of the lower mold molding surface.

For this reason, in Patent Document 1, a positioning member for an optical material is arranged in a mold, and this is moved in opposite directions around a reference position by driving means such as a rack and a pinion so that the optical material is sandwiched between them. By contacting and stopping, the optical material is positioned with respect to the mold.
However, according to this method, since the positioning member is arranged inside the mold, there is a problem that the mold has an extremely complicated structure. Furthermore, when a mold consisting of upper and lower molds is fixed to the press device, and the temperature rise, press, and cooling are performed at the same position, the molding material should be positioned by a movable member that complicates the device as described above. Is possible to some extent, but in the molding method (details will be described later), the molding material is housed in a molding die separated from the press device, and appropriately transferred while being transferred inside the device. It is extremely inefficient and substantially impossible to provide such a large movable member in the mold.

Further, in Patent Document 2, an element material setting member provided with an element material storage recess having an inner diameter substantially the same as the outer diameter of the optical element material is coupled to a suction means, and the lower mold is sucked while sucking the stored optical element material. However, in order to fit and house the optical element material in the concave portion, it is necessary to devise measures to prevent the relative positional relationship between the optical element material and the element material setting member from being shifted. It becomes.
If the positional relationship between the two is shifted, the optical element material is sucked and held while the optical element material is not fitted into the concave portion or the posture of the element material is inclined in the concave portion. Problems occur.

By the way, prior to press molding, placing the molding material at the center position of the lower mold molding surface is important in terms of the shape yield of the optical element to be molded and the surface accuracy of the optical function surface, as described above. However, for example, when the molding surface of the lower mold has a convex surface, or when a movable jig cannot be arranged around the molding surface due to the structure of the molding die, a molding material is placed on the molding die. After the supply, it is difficult to make the center of the molding surface and the molding material coincide with each other while the molding material is placed on the lower mold molding surface.
In such a case, when the molding material is held by a conveying means for supplying the molding material to the molding die (for example, a molding material holding unit of a robot equipped with a suction pad), the conveying means and the molding material are previously set. When the molding material is supplied to the molding die together with the positioning, the molding material is arranged at the center of the molding surface by controlling the relative position between the conveying means and the molding die in advance by a control computer or the like. It is effective to do so.

However, the molding material is not preliminarily molded into a predetermined range of volume and shape and then supplied to the mold one by one. After being arranged and accommodated, they are transported together from the preforming process to the press molding process. For this reason, during press molding, the molding material is accommodated in a tray or the like and waits for supply to the mold, but generally used trays can handle a plurality of types of molding materials. The storage section provided in the tray has a general-purpose shape, and in many cases, it does not have a shape that matches the shape of each molding material.
Therefore, the individual molding materials accommodated in the tray are accommodated in discrete positions in the respective accommodating sections of the tray.For example, when the molding material is adsorbed and held by the suction pad provided in the transport means, The positional relationship with the suction pad is not necessarily constant. If the molding material is picked up by the suction pad in such a state, the holding posture of the molding material by the suction pad is not constant, and the holding posture is inclined.

On the other hand, in Patent Document 3, in order to position the material center of the optical material (molding material) before molding at the center position of the optical material placement position, the optical material is positioned by the method described above. Yes.
However, in the method of positioning a moving member configured to be movable from the periphery of the optical material toward the positioning point by contacting the optical material, or the method of positioning by the bell clamp method, the reference on which the optical material is placed Driving means and the like must be arranged around the member, and a considerable space is required for that purpose. For this reason, there is a problem that the size of the apparatus is increased and the installation location is restricted. In addition, in the method of positioning by vibrating the reference member, when the optical material is covered with a convex curved surface, the optical material is hardly supported symmetrically on the support portion of the reference member, and the positioning accuracy is reduced. There's a problem.

  The present invention is considered in view of the above circumstances, and when the molding material is conveyed and supplied to the molding die, the positioning of the conveying means and the molding material is performed with high accuracy, and then the molding of the molding die is performed. Optical element manufacturing method and mold press molding apparatus capable of improving the shape yield of a press-molded optical element and the surface accuracy of an optical functional surface by supplying and arranging a molding material at the center position of the surface And a positioning method used for them, and further, a molding method including a pair of upper and lower molds is not fixed to the press device, and is appropriately processed while being transferred through the device. It is an object of the present invention to provide an optical element manufacturing method, a mold press molding apparatus, and a positioning apparatus used therefor, which are suitable for the above-mentioned and can efficiently mass-produce high-precision optical elements.

In order to achieve the above object, an optical element manufacturing method according to the present invention is a method for manufacturing an optical element in which a molding material is supplied to a molding die by a conveying means and press-molded, and the molding material is supplied to the molding die. In doing so, the molding material is placed on a positioning device, an airflow is ejected from the positioning device to correct the position of the molding material , and then the atmosphere is sucked to place the molding material on the positioning device. After fixing , the molding material and the conveying means are relatively positioned, and then the molding material is supplied to the mold by the conveying means.

  With such a method, even when it is difficult or inefficient to correct the position of the molding material on the molding surface, when the molding material is supplied to the molding die, the conveyance means and the molding material After performing mutual positioning with high accuracy, the molding material can be supplied and arranged accurately at the center position of the molding surface of the mold, so that the molding material is not unevenly distributed on the molding surface. The optical element can be manufactured with high accuracy by preventing deterioration of the surface accuracy of the optical function surface due to uneven thickness and uneven press load.

The optical element manufacturing method of the present invention may be a method in which the molding material is shaped on a receiving die by flowing or dropping molten glass and covered with a convex curved surface. it can.
With such a method, it is advantageous in terms of production efficiency, and an optical element can be manufactured using a molding material having a shape covered with a convex curved surface by hot molding without surface defects. At this time, by accurately supplying and arranging the molding material at the center position of the molding surface of the molding die, problems such as uneven distribution on the molding surface, which are conspicuous in the molding material having such a shape, can be solved.

Moreover, the manufacturing method of the optical element of this invention can be set as the method of pre-heat-treating the said shaping | molding raw material on the said positioning apparatus.
With such a method, in the heat treatment performed after the molding material is supplied to the molding die, the time required for the molding material to reach a temperature suitable for press molding can be shortened, and the molding material The temperature difference between the surface and the inside is alleviated, and it is possible to effectively avoid the inconvenience that the thickness accuracy and surface accuracy of the press-molded optical element are impaired due to the temperature difference between the surface and the inside of the molding material. it can.

Also, the method for manufacturing an optical element of the present invention includes transferring a molding die containing the molding material to a plurality of processing chambers including a heating chamber, a press chamber, and a cooling chamber, and sequentially including heating, pressing, and cooling. By performing the treatment, a method of press molding the molding material accommodated in the molding die can be obtained.
According to such a method, while simultaneously using a large number of molding dies, the temperature of the molding dies is efficiently raised and lowered, and the actual time (molding cycle time) required for molding per optical element is shortened. And production efficiency can be improved.
In the method of the present invention, since the relative positional relationship between the conveying means and the molding material is made constant, the molding material is accurately supplied and arranged at the center position of the molding surface of the molding die. Particularly suitable for a molding method based on the transfer of this type of mold, in which it is substantially impossible to correct the position of the molding material on the molding surface by providing a large movable member on the mold. be able to.

Further, the mold press molding apparatus of the present invention is a mold press molding apparatus for press molding a molding material, a pair of molding dies having opposing molding surfaces, and a conveyance for supplying the molding material to the molding die. and means, and a positioning device for relative positioning of the forming material and said conveying means, the positioning device has a receiving portion into which the molding material is placed, the placing of the receiving portion surface The molding material is floated on the receiving part by correcting the position by blowing an air flow from the opening provided in the container, and then the atmosphere is sucked to make the inside of the opening have a negative pressure. by fixing on said receptacle element can be said forming material, and configuration you relative positioning of the transport means.

  With such a configuration, even when it is difficult or inefficient to correct the position of the molding material on the molding surface, when the molding material is supplied to the molding die, the conveyance means and the molding material The mutual positioning can be performed with high accuracy, and the molding material can be supplied and arranged accurately at the center position of the molding surface of the molding die to avoid uneven distribution of the molding material on the molding surface.

The positioning device of the present invention is a positioning device that relatively positions the molding material and a conveying means for supplying the molding material to the molding die when the molding material is supplied to the molding die and press-molded. a is, the molding material has a receiving portion to be placed, and the air flow is jetting from the opening provided in the mounting surface of the receiving portion, the position resuspended said molding material on said receiving portion Then, by sucking the atmospheric gas and making the inside of the opening a negative pressure, the molding material is fixed on the receiving portion, so that the molding material and the conveying means are relative to each other. It may be configured you positioning.

  With such a configuration, the feeding means and the molding material can be positioned with high accuracy when the molding material is supplied to the molding die with a simpler structure.

In the positioning device of the present invention, the mounting surface of the receiving portion may have a concave curved surface.
With such a configuration, the molding material can be stably placed on the receiving portion even when, for example, a preforming material having a biconvex curved shape is used as the molding material.

Further, the positioning device of the present invention may be configured such that a pit having an inner diameter slightly larger than the outer diameter of the molding material is provided so as to surround the receiving portion.
With such a configuration, the position of the molding material can be corrected by the airflow ejected from the opening provided on the upper surface of the receiving portion and the inner peripheral surface of the drop hole.

Moreover, the positioning device of the present invention can be configured such that a heating means is installed around the receiving portion.
With such a configuration, the molding material can be preheated on the positioning device, and in the heat treatment performed after the molding material is supplied to the mold, the molding material has a temperature suitable for press molding. It is possible to shorten the time required to become, and the temperature difference between the surface and the inside of the molding material is alleviated. Due to the temperature difference between the surface and the inside of the molding material, the thickness accuracy of the press-molded optical element can be reduced. Inconvenience that the surface accuracy is impaired can be effectively avoided.

As described above, according to the present invention, when the molding material is supplied to the molding die, the conveying means and the molding material are positioned with high accuracy and then accurately positioned at the center position of the molding surface of the molding die. By supplying a molding material, it is possible to avoid uneven distribution of the molding material on the molding surface.
Thereby, the optical element can be manufactured with high accuracy by preventing unevenness of the optical element formed by press molding and deterioration of the surface accuracy of the optical functional surface due to non-uniformity of the press load.

  Hereinafter, preferred embodiments of a method for manufacturing an optical element, a mold press molding apparatus, and a positioning apparatus used for the optical element according to the present invention will be described with reference to the drawings.

[Positioning device (first embodiment)]
First, a first embodiment of a positioning device according to the present invention will be described. Here, FIG. 1 and FIG. 2 are explanatory views showing one step in an embodiment of an optical element manufacturing method according to the present invention, which will be described later, and a molding material is supplied to the mold by the positioning device according to this embodiment. 3 shows a positioning process in which the relative positional relationship between the conveying means for forming the molding material and the molding material is always constant.

In the present embodiment, the positioning device 1 is configured to supply a molding material 50 such as a glass preform to a molding die and press-mold the conveying device (in the illustrated example, a conveyance arm 60) that supplies the molding material 50 to the molding die. The receiving portion 2 is provided for positioning the molding material 50 and correcting the position of the molding material 50.
It is preferable that the receiving portion 2 has a dish shape in which an upper surface (a mounting surface on which the molding material 50 is mounted) is formed in a concave curved surface with a predetermined curvature. Thereby, even if the molding material 50 is preformed into a biconvex curved surface shape as shown in the drawing, the molding material 50 can be stably placed on the receiving portion 2.

  In the present embodiment, the material of the receiving portion 2 is not particularly limited and is preferably made of carbon in order to prevent fusion and reaction with the molding material 50, but the receiving portion 2 is formed of an appropriate material, A carbon layer can also be formed on the upper surface in contact with the molding material 50.

In addition, an opening 3 is provided substantially at the center of the upper surface of the receiving portion 2. From this opening 3, gas is supplied from a gas supply source (not shown) connected to the positioning device 1 through the gas passage 4, so that an air flow is ejected.
At this time, as the gas supplied from the gas supply source, for example, an inert gas such as nitrogen is used.

By the way, as will be described later, the mold containing the molding material 50 is transferred to a plurality of processing chambers including a heating chamber, a press chamber, and a cooling chamber, and processing including heating, pressing, and cooling is performed in each processing chamber. When the molding material 50 accommodated in the mold is press-molded, it is preferable to minimize the time required for processing in each processing chamber in order to shorten the molding cycle time.
However, during heat treatment, depending on the composition and volume of the molding material 50, unless a sufficient amount of heat is applied, the thickness accuracy and surface accuracy in the pressing process are adversely affected. For this reason, there is a limit to shortening the heating time, and if the heating time is increased in order to sufficiently heat the molding material 50, it is disadvantageous for shortening the molding cycle time. In order to achieve sufficient heating while shortening the molding cycle time, it is conceivable to increase the number of heating chambers. However, if the number of heating chambers is increased, it is necessary to modify existing equipment. In addition, it is necessary to further increase the number of molds, which is disadvantageous in terms of cost efficiency.

  In order to solve such a problem, in the illustrated example, the heating means 5 is provided around the receiving portion 2 so that the molding material 50 can be heated on the positioning device 1. Although the specific aspect of the heating means 5 is not specifically limited, For example, it can be based on resistance heating, high frequency induction heating, or the like. In addition, the heating temperature at this time is set in consideration of the heat resistance of the positioning device 1 and the like, the composition and volume of the molding material 50, and, for example, when the molding material 50 is a glass preform, about 100 to 300 ° C. It is preferable to do this.

If the molding material 50 is pre-heated on the positioning device 1 and the molding material 50 is preheated, the time required for the molding material 50 to reach a temperature suitable for press molding in the heat treatment in the heating chamber. This is advantageous for shortening the molding cycle time. That is, the pre-heat treatment is performed at the same time using a waiting time before the molding material 50 is supplied to the mold and the time required for correcting the position of the molding material.
Further, if there is a temperature difference between the surface and the inside of the molding material 50, there is a disadvantage that the thickness accuracy and surface accuracy of the press-molded optical element (molded body 51) are impaired. Such a temperature difference is likely to occur when the volume of the material is large, but the temperature difference between the surface and the inside of the molding material 50 is mitigated by pre-heating the molding material 50 prior to the heat treatment in the heating chamber. Thus, it is possible to effectively avoid the deterioration of the thickness accuracy and surface accuracy of the optical element (molded body 51).

Here, as will be described later, FIG. 4 is a schematic plan view showing an example of a mold press molding device, and the positioning device 1 described above is installed in the positioning portion P10. In the positioning part P10, the molding material 50 positioned relative to the transport means 60 by the positioning device 1 is transported to the disassembling / assembling part P9 and supplied to the molding die. Then, the molding material 50 is accommodated and assembled, and the molding die is transferred to the take-out / insertion chamber P1.
In this series of processes, in order to reduce heat radiation from the molding material 50 that has been pre-heated simultaneously by the positioning device 1, the positioning portion P10 (positioning device 1), together with the disassembling / assembling portion P9, takes out / insertion chamber. It is preferable to arrange in the vicinity of P1.

  In the positioning device 1 according to the present embodiment as described above, the relative positioning of the transport arm 60 as the transport means and the molding material 50 is performed prior to supplying the molding material 50 to the molding die. And the positioning process performed in the positioning device 1 is demonstrated, referring FIG.

  First, the forming material 50 is sucked and held one by one by a transfer arm 60 having a suction pad 61 at the tip from a transfer tray (not shown) arranged at a predetermined position, and transferred to the positioning device 1. .

Here, a plurality of molding materials 50 preformed in a predetermined shape are usually stored together in a transport tray and sequentially supplied to a molding die by a transport arm 60. In general, a general-purpose one is used so as to correspond to the material. For this reason, each molding material 50 accommodated in the tray is not accurately defined in the accommodation section, and the position and orientation of the molding material 50 in each accommodation section are not necessarily constant. .
Therefore, reflecting that the forming position of the molding material 50 is not accurately determined so that the molding material 50 has a fixed position and a fixed posture on the tray first, When the molding material 50 is sucked and held by the suction pad 61 provided in the transfer arm 60, the center position (center axis) of the suction pad 61 and the molding material 50 does not necessarily coincide with each other, and the molding is sucked and held by the suction pad 61. The posture of the material 50 is not constant (see FIG. 1 (1)).

  When transporting the molding material 50 to the positioning device 1, the transport arm 60 performs a predetermined three-dimensional movement based on the coordinate information previously input to the control unit of the robot, and sucks and holds the molding material 50 on the tray. Then, it is sequentially conveyed to the receiving part 2 of the positioning device 1 (see FIG. 1 (2)).

When the molding material 50 is conveyed to the receiving unit 2, the suction holding by the suction pad 61 is released, and the molding material 50 is placed on the receiving unit 2.
At this time, since the center positions of the molding material 50 and the suction pad 61 do not necessarily match as described above, the center axis of the molding material 50 placed on the receiving portion 2 and the center of the receiving portion 2 are also included. It does not necessarily coincide with the axis C, and the posture of the molding material 50 placed on the receiving portion 2 is not always constant (see FIG. 1 (3)).

After the molding material 50 is placed on the receiving part 2, gas is supplied from a gas supply source (not shown) through the gas passage 4, and an air flow is ejected from the opening 3 provided on the upper surface of the receiving part 2. As a result, as indicated by an arrow in the figure, an air flow is generated upward around the molding material 50 placed on the receiving portion 2.
Then, due to this air flow, a gas layer is formed between the molding material 50 and the receiving part 2, and the molding material 50 floats on the receiving part 2, and goes to the center position of the most stable receiving part 2. To move. Thereby, the position of the molding material 50 on the receiving portion 2 is corrected, and the molding material 50 is positioned so that the central axis of the molding material 50 and the central axis C of the receiving portion 2 coincide (FIG. 1 ( 4)).

Next, the gas supply from the gas supply source is stopped and the atmosphere gas is sucked from the gas passage 4 so that the inside of the opening 3 is in a negative pressure state, thereby fixing the molding material 50 on the receiving portion 2 ( 2 (see FIG. 2 (5)), the suction pad 61 of the transfer arm 60 is brought close to the molding material 50, and the molding material 50 is sucked and held.
At this time, the center position of the molding material 50 and the suction pad 61 is controlled by controlling the movement of the transport arm 60 so that the central axis of the suction pad 61 of the transport arm 60 and the central axis C of the receiving portion 2 coincide with each other. Are substantially coincident with each other, and the relative positioning of the transfer arm 60 and the molding material 50 is performed (see FIG. 1 (6)).

Thereafter, the molding material 50 is taken out from the positioning device 1 by the transport arm 60, and transported and supplied to the molding die (see FIG. 2 (7)).
The molding material 50 supplied and accommodated in the molding die is press-molded by a predetermined treatment, which will be described later.

As described above, the positioning device 1 in the present embodiment performs relative positioning between the transporting means for supplying the molding material 50 to the molding die and the molding material 50. The conveying means that conveys the molding material 50 may be the same as the conveying means that conveys (feeds) the molding material 50 from the positioning device 1 to the mold, and both conveying means may be independent. .
If the conveying means that conveys the molding material 50 to the positioning device 1 and the conveying means that conveys the molding material 50 from the positioning device 1 to the molding die are separate and independent, the positioning of one molding material 50 is completed, and positioning is performed. Immediately after being taken out from the apparatus 1, the next molding material 50 can be placed on the receiving portion 2, and the time during which the molding material 50 stays in the positioning device 1 can be lengthened. Such an aspect is advantageous in securing the heating time when the pre-heat treatment is performed on the molding material 50 on the positioning device 1.

[Positioning device (second embodiment)]
Next, a second embodiment of the positioning device according to the present invention will be described. Here, FIG. 3 shows a part of the positioning step in which the relative positional relationship between the conveying means for supplying the molding material to the molding die and the molding material is always constant by the positioning device according to the present embodiment. It is explanatory drawing shown.

The positioning device 1 in the present embodiment is different from the first embodiment in the configuration of the receiving portion 2.
In the first embodiment, the receiving part 2 has a dish shape whose upper surface is formed into a concave curved surface with a predetermined curvature so that the molding material 50 can be stably placed on the receiving part 2. However, in the present embodiment, as shown in the drawing, a drop hole 6 having an inner diameter slightly larger than the outer diameter of the molding material 50 is provided so as to surround the receiving portion 2 and around the opening of the drop hole 6. The guide surface 7 which inclines below toward the drop hole 6 is provided.

Thereby, the molding material 50 conveyed on the guide surface 7 is guided by the guide surface 7 and dropped onto the receiving portion 2 (see FIG. 3A).
That is, when the molding material 50 conveyed to the guide surface 7 by the conveyance arm 60 is released from the suction holding by the suction pad 61, the molding material 50 slides down on the guide surface 7 as shown by a one-dot broken line in the drawing, and the pit is dropped. 6 and is placed on the receiving portion 2.

After the molding material 50 is placed on the receiving portion 2, the gas is supplied from the gas supply source (not shown) through the gas passage 4 as in the first embodiment. Accordingly, the molding material 50 is positioned by the air flow ejected from the opening 3 provided on the upper surface of the receiving portion 2 indicated by the arrow in the drawing and the inner peripheral surface of the drop hole 6 (see FIG. 3B). .
As described above, the positioning device 1 according to the present embodiment involves the inner peripheral surface of the drop hole 6 to be involved in the positioning of the molding material 50. Therefore, the dimensional management is easy, and the preform is preformed into a disk shape as illustrated by polishing. This is particularly suitable when the formed molding material 50 is used.

Since the other configuration of the present embodiment is substantially the same as that of the first embodiment, a detailed description of the other configuration is omitted, but also in the present embodiment, after the molding material 50 is positioned, In the same manner as described in the first embodiment, the atmospheric gas is sucked from the gas passage 4 and fixed on the receiving portion 2 (see FIG. 3C). It is sucked and held by the transfer arm 60, and transferred and supplied to the mold.
Also in this embodiment, the heating means 5 can be installed around the receiving portion 2 as in the first embodiment.

[Mold press molding equipment]
Next, an embodiment of a mold press molding apparatus according to the present invention (hereinafter simply referred to as a molding apparatus) will be described. Here, FIG. 4 is a schematic plan view of a rotary transfer type molding apparatus shown as an example of the molding apparatus according to the present embodiment.

  The molding apparatus in the present embodiment is for press-molding a molding material 50 supplied to a molding die, and a plurality of processing chambers arranged side by side in a circumferential direction in the molding area with an extraction / insertion chamber P1. P2 to P8, and a disassembly / assembly part P9 and a positioning part P10 outside the molding area.

In the take-out / insertion chamber P1, an operation for taking out a molding die that has been molded and an operation for inserting a molding die containing a molding material 50 to be newly molded are performed without impairing the setting environment in the molding area. Is called.
The molding die taken out from the take-out / insertion chamber P1 is transferred to the disassembling / assembling part P9 outside the molding area, and disassembled to take out the press-molded molded body 51. Then, the disassembled mold waits for a new molding material 50 to be used for molding to be supplied as it is.

The positioning device 1 as described above is installed in the positioning portion P10. Prior to supplying the molding material 50 to the molding die, the conveying means for feeding the molding material 50 to the molding die and the relative relationship between the molding material Positioning is performed. As described above, the positioning part P10 is preferably provided in the vicinity of the take-out / insertion chamber P1 together with the disassembly / assembly part P9.
The molding material 50 whose relative positional relationship with the conveying means is constant is supplied by the conveying means to a molding die waiting in the disassembling / assembling part P9, and the molding die is assembled by accommodating the molding material 50. .

A molding die containing a molding material 50 to be newly used for molding is inserted into the molding area from the take-out / insertion chamber P1, and held on a holding table attached to a rotary table that rotates in the direction of the arrow in the figure. Thus, it is sequentially passed through the processing chambers P2 to P8 which are always under a non-oxidizing gas atmosphere (inert gas atmosphere).
In the take-out / insertion chamber P1 that is not in an inert gas atmosphere, it is preferable to control the temperature of the mold so that the temperature of the mold becomes 250 ° C. or less in consideration of prevention of oxidation of the mold.

  The rotary table rotates intermittently at regular intervals, and the mold moves between adjacent processing chambers by this intermittent rotation. And this fixed time becomes a molding cycle time.

Here, P2 is a first heating chamber, P3 is a second heating chamber, and P4 is a third heating chamber (or soaking chamber), which are also collectively referred to as a heating unit. P5 is a press chamber, and a press load is applied to a mold set at a temperature suitable for press molding in the heating section. P6 is a first slow cooling chamber, P7 is a second slow cooling chamber, and P8 is a rapid cooling chamber. These are also collectively referred to as a cooling section, and the mold is cooled after a press load is applied.
These processing chambers P2 to P8 are arranged at substantially equal intervals, and are controlled to a temperature suitable for each processing, and in order to keep the temperature in each processing chamber at a predetermined temperature, shutters S1 to S6 are used. It is partitioned.

If such a molding apparatus is used, a desired optical element can be efficiently obtained by subjecting the molding die containing the molding material 50 (or the molded body 51) to appropriate processing while sequentially transferring the molding die. Can be manufactured.
That is, since the temperature of the mold is increased to a temperature suitable for press molding, press load is applied, and the subsequent cooling process is performed by the mold passing through each processing chamber arranged two-dimensionally. These molds can be used simultaneously, and the substantial molding cycle time is shortened.

  In the molding apparatus according to the present embodiment, the molding die containing the molding material 50 (or the molded body 51) is transferred to each processing chamber such as a heating chamber, a press chamber, and a cooling chamber, and heated and pressed. Appropriate processing including cooling is sequentially performed, but the specific configuration for transferring the mold to each processing chamber is not limited to the above example. For example, in the above-described example, the mold is transferred by the rotary table, but it is configured so that it can pass through each processing chamber arranged two-dimensionally (in some cases three-dimensionally) at a predetermined time interval. If it is what is carried out, the means in particular to transfer a shaping | molding die will not be restrict | limited.

Further, the arrangement configuration of each processing chamber can be appropriately changed in order to optimize the heating process and the cooling process in accordance with the composition of the molding material 50 and the shape of the optical element to be obtained. For example, the number of heating chambers can be changed to four, or the number of slow cooling chambers can be changed to three, but as described above, if the molding material 50 is preheated by the positioning device 1, The heating process can be optimized without adding a new heating chamber that occupies the molding area.
In order to further improve production efficiency, the same number of heating chambers, press chambers, cooling chambers, etc. are provided in series, and multiple types of press molding that require different temperature conditions and different pressurization conditions are performed simultaneously. It may be.

  Further, in order to improve production efficiency, for example, a plurality of molds are provided in each processing chamber by allowing a plurality of holding stands used in the same process to pass through each processing chamber at the same time. It can be processed simultaneously. Specifically, when processing such as heating, application of a press load, and cooling processing is performed in each processing chamber, two or more molding dies can be arranged and the same processing can be simultaneously performed on them. In this case, the press chamber is preferably provided with two or more pressing means corresponding to the number of molds.

[Mold press mold]
Next, an example of a mold press mold (hereinafter simply referred to as a mold) suitably used in the present invention will be described. Here, FIG. 5 is a schematic cross-sectional view of the mold and shows a state when a press load is applied (see FIG. 7 (14)). 6-8 is explanatory drawing which shows a part of process in embodiment of the manufacturing method of the optical element which concerns on this invention mentioned later.

  The molding die shown in FIG. 5 includes an upper die 10, a lower die 20, a barrel die 30 and a support member 40, and press-molds a molding material 50 between the upper die 10 and the lower die 20.

In the example shown in the figure, the body mold 30 is configured so that the upper and lower molds 10 and 20 are slidably guided when assembling the molding mold or press molding, thereby restricting the horizontal relative positions thereof. The coaxiality of 10, 20 is ensured.
For this reason, the sliding clearance between the body mold 30 and the upper and lower molds 10 and 20 is preferably 10 μm or less, particularly 5 μm or less in consideration of the required eccentric accuracy of the optical element. If the sliding clearance is controlled, the eccentricity between the molding surfaces 11 and 21 of the upper and lower molds 10 and 20 (shift: horizontal displacement of the molding surfaces 11 and 21 of the upper and lower molds 10 and 20, tilt: upper and lower molds 10 and 20. Can be suppressed with high accuracy.

  In the optical element manufacturing method described later, during press molding, the upper mold 10 is slidably guided in the trunk mold 30 with respect to the lower mold 20 fitted in the trunk mold 30, and the upper and lower molds 10, 20. Although the example which comprised so that it may approach and space | interval relatively is demonstrated, it can also comprise contrary to this. That is, the lower mold 20 may be slidably guided in the body mold 30 with respect to the upper mold 10 fitted in the body mold 30, and the upper and lower molds 10 and 20 ensure the coaxiality. However, the specific configuration is not limited as long as they are relatively close to and away from each other.

  The body mold 30 is provided with a vent hole 33 for preventing the movement of the upper and lower molds 10 and 20 from being hindered by the pressure difference between the inside and outside of the mold when the upper and lower molds 10 and 20 approach and separate. It is preferable to keep it. In particular, as shown in the figure, a vent hole 33 is provided in a portion where the inner diameter of the body mold 30 is changed to be a stepped portion, and the inside of the mold is always kept at an external pressure with respect to the increase or decrease of the volume in the gap of the stepped portion. It is preferable that the atmospheric gas is conducted through the vent hole 33 so as to be equal. In addition, the support member 40 is preferably provided with a vent hole 41 for the same purpose as the trunk mold 30. This makes it possible to smoothly perform press molding and assembly / disassembly of the mold.

  The upper mold 10 has a molding surface 11 formed on the lower surface facing the lower mold 20. In the illustrated example, the molding surface 11 is a convex surface, but may be a concave surface or a flat surface. Further, a flange portion 12 having a diameter larger than that of the molding surface 11 is formed at the upper portion of the upper mold 10, and this flange portion 12 is accommodated in a large-diameter inner peripheral portion 31 formed at the upper portion of the body mold 30. The

  At this time, when the upper surface of the upper mold 10 and the upper surface of the trunk mold 30 are flush with each other, the lower surface of the flange portion 12 formed on the upper mold 10 and the small-diameter inner peripheral section formed on the trunk mold 30 It is preferable that a gap G having a predetermined dimension or more is secured between the upper end of 32. By securing such a gap G, the upper die 10 is pushed in until the upper surface of the upper die 10 coincides with the upper surface of the barrel die 30 during press molding, and the thickness of the molded body 15 is once determined. However, it is possible to continue to apply the necessary load (only the weight of the upper mold 10 may be applied) to the molded body 51 and to allow the upper mold 10 to descend following the thermal contraction of the molded body 51 (FIG. 7 (14) and (15)).

  In the illustrated example, a molding surface 21 having a convex surface is formed on the upper surface facing the upper mold 10 of the lower mold 20, but the molding surface 21 formed on the lower mold 20 is a flat surface or a concave surface. There may be. Further, a flange portion 22 having a diameter larger than that of the molding surface 21 is formed at the lower portion of the lower mold 20. At the time of press molding, the lower surface of the barrel die 30 is brought into contact with the upper surface of the flange portion 22 and is brought into close contact with each other by the press pressure, whereby the mutual position of the lower die 20 and the barrel die 30 is defined with high accuracy. This also suppresses the tilt.

  Further, a step portion 23 is formed on the outer periphery of the molding surface 21 of the lower mold 20 at a position lower than the molding surface 21 and higher than the flange portion 22, and surrounds the molding surface 21 around the step portion 23. In addition, an annular support member 40 is placed.

  At this time, the vent hole 41 provided in the support member 40 described above is provided at a position where the molding material 50 does not enter the vent hole 41 during press molding. Specifically, the support member 40 is placed on the step portion 23. In this state, it is preferable that the support member 40 is provided at a position between the peripheral portion of the molding surface 21 of the lower mold 20 and the step portion 23 in the axial direction.

  In the illustrated example, the vent hole 41 is provided so as to penetrate the support member 40 in a substantially radial direction, and the clearance between the inner peripheral surface of the support member 40 and the lower mold 20, the outer peripheral surface of the support member 40 and the trunk shape. 30 and the air hole 33. Thereby, when the atmospheric gas existing in the space between the molding material 50 and the lower mold molding surface 21 is compressed by the proximity of the upper and lower molds 10 and 20 (press molding), the atmospheric gas in the molding mold is supported. The clearance between the inner peripheral surface of the member 40 and the lower mold 20, the vent hole 41 of the support member 40, the clearance between the outer peripheral surface of the support member 40 and the trunk mold 30, and the vent hole 33 of the trunk mold 30. Can be released to the outside.

Therefore, by providing such a vent hole 41, it is possible to balance the inside of the mold and the external pressure by releasing the atmospheric gas to the outside of the mold.
As will be described later, the clearance between the outer peripheral surface of the support member 40 and the trunk mold 30 does not directly affect the eccentricity accuracy of the optical element to be molded, and therefore the ventilation hole 41 of the support member 40 and the ventilation hole 33 of the trunk mold 30 are formed. The communication can be set to such an extent that the atmospheric gas is discharged without hindrance.

  The support member 40 supports the molding material 50 supplied on the lower mold 20 to prevent the molding material 50 from slipping or shifting, but supports the peripheral portion on the lower surface side of the molding material 50. The specific configuration is not particularly limited as long as an open space can be secured outside the peripheral edge of the molding material 50 supported by the support member 40. By securing an open space outside the peripheral edge of the molding material 50 supported by the supporting member 40, the maximum outer diameter of the molding material 50 varies due to individual differences in the molding material 50 supplied onto the lower mold 20. In some cases, even when the horizontal cross section of the molding material 50 is not a perfect circle and there is a difference in length depending on the part of the molding material 50, the molding material 50 is stably supported and the state is maintained. be able to.

Here, the support means that the molding material 50 can maintain a certain posture. Further, the position at which the molding material 50 is supported by the supporting member 40 (peripheral portion on the lower surface side) can stably support the molding material 50, and the optical effective diameter of an optical element such as a lens to be obtained, Preferably, the centering diameter (the process of cutting the outer periphery of the press-formed molded body 51 in order to make the outer diameter center coincide with the optical center, that is, the final optical element after the centering process is performed. It is preferable to satisfy the following relational expression (1), and the following relational expression (1) is satisfied.
[Optical effective diameter] ≦ [Optical element effective diameter (= centering diameter)] <[Inner diameter of support member (support position)] <[Diameter of molding material] (1)

  More specifically, preferably, the molding material 50 is supported when the molding material 50 having a maximum outer diameter larger than the effective diameter of the optical element is used and the molding material 50 has a maximum outer diameter (diameter) of 2r. The position is preferably in the range of 0.5 to 0.95r from the center of the molding material 50, and more preferably in the range of 0.7 to 0.95r. Thereby, the removal rate at the time of performing the centering process on the molded body 51 is reduced, and efficient production becomes possible.

The support member 40 may be formed integrally with the lower mold 20, but may be formed separately from the lower mold 20. When the support member 40 is formed separately from the lower mold 20, the support member 40 may be fixed to the lower mold 20 using a pin or the like, but the support member 40 may be provided to be detachable from the lower mold 20. it can.
In order to detachably mount the support member 40 formed separately on the outer periphery of the molding surface 21 of the lower mold 20, for example, as shown in the drawing, around the molding surface 21 of the lower mold 20, the molding surface The step portion 23 may be formed at a position lower than 21 and higher than the flange portion 22, and the support member 40 may be placed on the step portion 23.

  When the support member 40 is detachable, the support member 40 can be taken out of the mold together with the molded body 51 when the press-molded molded body 51 is taken out from the molding surface 21 of the lower mold 20. For this reason, after the press molding, if the molded body 51 and the support member 40 are taken out from the mold while being in close contact with each other, and then the support member 40 is removed from the molded body 51 when the temperature is further lowered, Both can be easily separated.

Moreover, it is preferable that the inner periphery of the support member 40 is tapered, and has an inclined surface such that the inner diameter becomes smaller toward the lower side (closer to the molding surface 21 of the lower mold 20). Thereby, at the time of press molding, it is possible to avoid the occurrence of poor filling or pressurization in the portion along the outer periphery of the molding surface 21, and the outer diameter of the molding material 50 is increased more than necessary in order to ensure an effective optical element diameter. In order to prevent the usage amount (volume) of the molding material 50 from increasing excessively, it is effective to form such an inclination on the inner periphery of the support member 40.
The clearance between the support member 40 and the body mold 30 is not directly related to the eccentricity accuracy of the optical element, and may be about 5 to 50 μm. The clearance between the center of the outer diameter of the optical element to be obtained and its optical axis. Consistency can be obtained by centering the press-molded molded body 51.

  The shape and dimensions of the support member 40 are such that at least the upper end edge on the inner peripheral surface side of the support member 40 is sufficient to support the lower surface side peripheral portion of the molding material 50 supplied onto the lower mold 20. If the upper end side of the member 40 protrudes upwards rather than the molding surface 21 of the lower mold | type 20, it will not restrict | limit in particular (refer FIG. 6 (10)).

At this time, the molding material 50 may be in a state of being in contact with the molding surface 21 of the lower mold 20 or in a state of being supported only by the support member 40 without being in contact with the molding surface 21 of the lower mold 20. However, in particular, when press molding is performed using the molding apparatus as described above, the molding die in which the molding material 50 is accommodated is heated together with the molding material 50. When the material 50 and the mold (the molding surface 21 of the lower mold 20) are in contact with each other, a reaction occurs between the two at the interface, and the molding material is fused to the molding surface 21 and the molded body 51 It may cause fogging or foaming on the molding surface. For this reason, it is preferable that the upper end side of the support member 40 protrudes above the molding surface 21 of the lower mold 20 to such an extent that the molding material 50 can be supported so as not to contact the molding surface 21 of the lower mold 20.
In such a mode, in the molding apparatus as described above, the lower mold 20 is more likely to be heated more strongly due to the heat capacity of the holding table that holds the mold, or a phosphate glass material, W, Ti, Nb, etc. Particularly effective when press-molding using a highly reactive glass material such as a glass material containing a large amount of high refractive index component (eg, nd ≧ 1.7) or a glass material containing a large amount of alkali metal. It is.

  The portion of the support member 40 that supports the molding material 50 (upper end edge on the inner peripheral side) may have a square shape, or may have an R chamfer or a C chamfer. It may be a curved surface shape along the curved surface of the molding material 50. Further, when the molding material 50 is supported, the support member 40 is not particularly required to be in contact with the molding material 50 over the entire circumference of the molding material 50, and is formed with the molding material 50 having a predetermined interval in the circumferential direction. The support member 40 may support the molding material 50 by partial contact.

In such a mold, there are no particular limitations on the materials of the upper mold 10, the lower mold 20, the trunk mold 30, and the support member 40. Cermet such as silicon carbide, silicon, silicon nitride, tungsten carbide, aluminum oxide and titanium carbide, or those coated with diamond, refractory metal, noble metal alloy, carbide, nitride, boride, oxide, etc. Can be mentioned.
A single component layer or a mixture of amorphous and / or crystalline graphite and / or diamond is formed on the molding surfaces 11 and 21 of the upper and lower molds 10 and 20 and the support member 40 in order to prevent glass fusion. It is preferable to use a carbon film composed of layers or a release film made of a noble metal alloy.

[Method for Manufacturing Optical Element]
Next, an embodiment of a method for manufacturing an optical element according to the present invention will be described with an example in which the mold shown in FIG. 5 is applied to the molding apparatus shown in FIG. Here, FIG. 1 is explanatory drawing which shows process (1)-(4) in the manufacturing method of the optical element which concerns on this embodiment, FIG. 2 is explanatory drawing which shows the said process (5)-(7), figure. 6 is an explanatory view showing the steps (8) to (11), FIG. 7 is an explanatory view showing the steps (12) to (15), and FIG. 8 is a view showing the steps (16) to (18). It is explanatory drawing.

Steps (1) to (7): Positioning step In the present embodiment, first, from a transfer tray (not shown) arranged at a predetermined position, a transfer arm 60 provided with a suction pad 61 at the tip, The molding material 50 is sucked and held one by one, and is conveyed to the positioning device 1 installed in the positioning part P10.
At this time, since the positional relationship between the molding material 50 on the tray and the suction pad 61 is not constant, the posture of the molding material 50 sucked and held by the suction pad 61 is not constant (see FIG. 1 (1)). ).

When the molding material 50 is conveyed to the receiving part 2 (see FIG. 1B), the suction holding by the suction pad 61 is released, and the molding material 50 is placed on the receiving part 2.
At this time, since the posture of the molding material 50 sucked and held by the suction pad 61 is not constant, the posture of the molding material 50 placed on the receiving portion 2 is also not constant (see FIG. 1 (3)). .

  After the molding material 50 is placed on the receiving part 2, gas is supplied from a gas supply source (not shown) through the gas passage 4, and an air flow is ejected from the opening 3 provided on the upper surface of the receiving part 2. As a result, an air current as indicated by an arrow in the figure is generated, and the position of the molding material 50 on the receiving portion 2 is corrected by this air current, and the central axis of the molding material 50 and the central axis C of the receiving portion 2 are The molding material 50 is positioned so as to match (see FIG. 1 (4)).

Next, gas supply from the gas supply source is stopped , and atmospheric gas is sucked from the gas passage 4 to fix the molding material 50 on the receiving portion 2 (see FIG. 2 (5)). Then, the conveyance arm 60 controlled so that the center of the suction pad 61 and the central axis C of the receiving portion 2 coincide with each other is approached, and the molding material 50 is sucked and held on the conveyance arm 60, thereby The relative positional relationship between the suction pad 61 and the molding material 50 can be made constant (see FIG. 2 (6)).
Then, the molding material 50 taken out from the positioning device 1 is conveyed and supplied to the molding die (see FIG. 2 (7)).

In the above steps (1) to (7), the molding material 50 is heated on the positioning device 1 by the heating means 5 installed around the receiving portion 2, and simultaneously with the positioning of the molding material 50, the molding material. 50 can be preheated. For example, when the molding material 50 is a glass preform, the heating temperature at this time is preferably about 100 to 300 ° C.
By using the time required for positioning of the molding material 50 on the positioning device 1, the molding material 50 is subjected to a pre-heat treatment so that the molding material 50 has a temperature suitable for press molding in a heating process described later. The time required for the process can be shortened, and the temperature difference between the surface and the inside of the molding material 50 is relaxed, and the thickness accuracy and surface accuracy of the press-molded optical element (molded body 51) are improved. Therefore, such an embodiment is advantageous not only in shortening the molding cycle time but also in molding accuracy.

Steps (8) to (10): Molding material supply step After the relative positional relationship between the suction pad 61 of the transport arm 60 and the molding material 50 is made constant, the molding material 50 is replaced with the lower mold 20 and the upper mold 10. Are conveyed (supplied) to a mold that is waiting in a state of being separated from each other. At this time, the position of the body mold 30 in which the upper mold 10 is incorporated is fixed by the holding means 80 (see FIG. 6 (8)).
When the suction pad 61 of the transfer arm 60 reaches the molding surface 21 of the lower mold 20 with an accuracy within a predetermined range (see FIG. 6 (9)), the suction is released and the transfer arm 60 is immediately moved. Evacuate.
Thereby, the peripheral part of the lower surface side of the molding material 50 is supported by the upper end edge on the inner peripheral side of the support member 40, and is held on the support member 40 without sliding down (see FIG. 6 (10)). .

Here, in the illustrated example, a molding die having a convex molding surface is used, and it is difficult to correct the position of the molding material 50 on the lower die 20. The molding material 50 is supported by 40 to prevent the molding material 50 from slipping or being displaced. However, if the relative positional relationship between the transport arm 60 and the molding material 50 is not constant, the molding material 50 is supported by the support member 40. Can not be supported well.
However, in this embodiment, before the molding material 50 is supplied to the molding die, the molding material 50 is positioned so that the relative positional relationship between the transport arm 60 and the molding material 50 is always constant. The molding material 50 can be reliably supported at a predetermined position of the support member 40.

Step (11): Assembly Step of Molding Mold After retracting the transfer arm 60, the mounting table 70 is raised and the lower die 20 is assembled into the body die 30. When the lower mold 20 is incorporated in the body mold 30 and the upper surface of the flange portion 22 of the lower mold 20 abuts on the lower surface of the body mold 30, the upper surface of the upper mold 10 is made to be the body mold 30 depending on the thickness of the molding material 50. (See FIG. 6 (11)).

  At this time, the clearance between the body mold 30 and the lower mold 20 is preferably 5 μm or less. Further, it is preferable that the upper mold 10 and the trunk mold 30 assembled in advance have the same clearance. Thereby, the eccentricity between the molding surfaces 11 and 21 of the upper and lower molds 10 and 20 can be suppressed with high accuracy. Further, when assembling the molding die, the upper die 10 and the barrel die 30 may be lowered by the holding means 80 instead of raising the mounting table 70.

  In the above steps (8) to (11), the mounting table is obtained by sucking the atmospheric gas from the opening 71 provided in the mounting table 70 so that the lower mold 20 does not shift on the mounting table 70. The lower mold 20 can be adhered and fixed on the 70. Further, as will be described later, when the mold is disassembled, the lower mold 20 is brought into close contact with the mounting table 70 by suction of the atmospheric gas, and the position when the lower mold 20 is extracted from the body mold 30 is maintained. Thus, it is possible to avoid the horizontal relative position of the lower mold 20 and the trunk mold 30 from shifting.

  In the molding apparatus shown in FIG. 4, the above steps (8) to (11) are performed in the disassembling / assembling part P9, and the molding die accommodated and molded with the molding material 50 is taken out from the taking-out / inserting chamber P1. However, the disassembly / assembly part P9 may be omitted, and the above steps (8) to (11) may be performed in the take-out / insertion chamber P1.

Step (12): Heating step The mold assembled with the molding material 50 contained therein is held on a holding stand 75 attached to the rotary table, and heated while being sequentially transferred to the heating chambers P2 to P4. Then, the temperature of the molding material 50 together with the molding die is raised to a temperature suitable for press molding (see FIG. 7 (12)).

At this time, for example, the first heating chamber P <b> 2 maintains a high temperature equal to or higher than the pressing temperature of the molding material 50 and rapidly heats the molding die and the molding material 50. And the shaping | molding die in which the shaping | molding raw material 50 was accommodated is stopped for a predetermined time in the 1st heating chamber P2, and is transferred to the 2nd heating chamber P3 according to rotation of a turntable. Due to the heating in the second heating chamber P3, the mold and the molding material 50 are further heated and soaked to approach the press temperature. Next, the molding die and the molding material 50 are soaked in the third heating chamber P4 so that the viscosity of the molding material 50 is 10 ⁶ to 10 ⁹ poise suitable for press molding. Preferably, the temperature of the molding material 50 is The temperature is set to a viscosity of 10 ⁶ to 10 ⁸ poise.

  In addition, there is no restriction | limiting in particular in the heating means with which the heating chambers P2-P4 are equipped. For example, a heater by resistance heating, a high frequency induction coil, or the like can be used.

Steps (13) to (14): Pressing step The mold that has reached an appropriate temperature is transferred to the press chamber P5 (see FIG. 7 (13)). In the press chamber P5, a press load is applied to the mold by a press head 90 from above the mold at a predetermined pressure (for example, 30 to 200 Kg / cm ² ) and for a predetermined time (for example, several tens of seconds) (FIG. 7). (Refer to (14)). At this time, the atmospheric gas interposed between the lower mold 20 and the molding material 50 is released to the outside of the molding die via the vent hole 41 of the support member 40 and the vent hole 33 of the trunk mold 30.
When the lower surface of the press head 90 comes into contact with the upper surface of the body mold 30, the thickness of the molded body 51 is defined, and then the press head 90 is lifted to cancel the application of the press load, thereby completing the pressing process. To do.

Step (15): Cooling Step After the pressing step, the forming mold is sequentially transferred to the slow cooling chambers P6 and P7 and the rapid cooling chamber P8 to perform a cooling process (see FIG. 7 (15)). In the quenching chamber P8, quenching with a cooling gas can be performed, and the molded body 51 is cooled to a temperature that does not hinder the opening to the atmosphere.
At this time, in the molding die, the gap G as described above is secured with a predetermined dimension between the lower surface of the flange portion 12 of the upper die 10 and the upper end of the small-diameter inner peripheral portion 32 of the body die 30. Thus, it becomes possible for the upper mold 10 to follow the shrinkage of the glass by its own weight, and good shape accuracy can be obtained.
In addition, when the upper mold | type 10 descend | falls following the shrinkage | contraction of glass, the space | interval of the clearance gap G between the flange part 12 of the upper mold | type 10 and the upper end surface of the small diameter inner peripheral part 32 of the trunk | drum 30 will become narrow.

Steps (16) to (17): Mold Disassembling Step The mold subjected to the cooling process is taken out from the take-out / insertion chamber P1, transferred to the disassembly / assembly part P9, and provided in the disassembly / assembly part P9. It mounts on the mounting base 70 (refer FIG. 8 (16)). Then, the holding means 80 fixes the position of the body mold 30 in which the upper mold 10 is incorporated, and sucks the atmospheric gas from the opening 71 of the mounting table 70 so that the lower mold 20 is integrated on the mounting table 70. Then, the mounting table 70 is lowered vertically, and the lower mold 20 is extracted from the trunk mold 30 (see FIG. 8 (17)).
At this time, the lower mold 20 is integrally held on the mounting table 70, and the position when the lower mold 20 is extracted from the trunk mold 30 is maintained, so that the lower mold 20 and the trunk mold 30 are aligned in the horizontal direction. It is possible to avoid shifting the position.

Step (18): Step of taking out the molded body After the lower mold 20 is extracted from the body mold 30, the molded body 51 is sucked and held by the suction pad 61 of the transfer arm 60, and the molded body 51 is formed on the molding surface 21 of the lower mold 20. Is taken out (see FIG. 8 (18)).
The molded body 51 taken out from the mold in this way can be made into a desired optical element as it is or by performing a centering process as necessary.

  In the illustrated example, the support member 40 is fixed to the lower mold 20. However, the support member 40 is provided so as to be detachable from the lower mold 20, and the formed body 51 and the support member 40 are in close contact with each other. You may make it take out from a shaping | molding die with the state which carried out. If it does in this way, the support member 40 can be removed from the molded object 51 when temperature falls more, and both can be isolate | separated easily. However, in this case, a plurality of support members 40 are prepared, and the support members 40 are supplied onto the lower mold 20 prior to the molding material supply process (the above processes (8) to (10)). It is necessary to keep.

  After these steps (1) to (18) are completed, the process can be continuously performed by returning to step (1) and repeating the above cycle.

If an optical element is manufactured in this way, the mold is transferred to a plurality of processing chambers including heating chambers P2 to P4, a press chamber P5, and cooling chambers P6 to P7, and heating, pressing, and cooling are performed in each processing chamber. Since the molding material 50 accommodated in the mold is press-molded by performing the process including the above, the temperature of the mold is raised and lowered efficiently while simultaneously using a large number of molds. Efficiency can be improved.
The optical element manufacturing method according to the present embodiment supplies and arranges the molding material accurately at the center position of the molding surface of the molding die by making the relative positional relationship between the conveying means and the molding material constant. Therefore, it is possible to provide a molding method based on the transfer of this type of mold, which makes it impossible to correct the position of the molding material on the molding surface by providing a large movable member for each mold. It can be applied particularly preferably.

Moreover, there is no restriction | limiting in particular in the material of the shaping | molding raw material 50 used for this embodiment, It can be set as glass raw materials, such as a glass preform, For example, block-shaped optical glass is cut | disconnected and grind | polished, disk shape, It can be processed into a spherical shape or the like (cold processing). Alternatively, the optical glass may be preformed (hot-molded) into a spherical shape or a biconvex curved shape by dropping or flowing down from a molten state onto a receiving mold.
In the present embodiment, it is preferable to use a cold-worked disk-shaped glass material or a hot-formed biconvex curved glass material as the molding material 50, but in particular, a biconvex curved shape by hot forming. Things (covered by convex curved surfaces) are extremely advantageous in terms of production efficiency. Although the molding material 50 covered with the convex curved surface is likely to have problems such as uneven distribution due to rolling on the molding surface, in this embodiment, when the molding material 50 is transported and supplied to the molding die, Such a problem can be solved by supplying and arranging the molding material at the center position of the molding surface of the molding die after positioning with the molding material 50 with high accuracy.

  As described above, in the optical element manufacturing method according to the present embodiment, the molding material 50 is not positioned on the molding surface 21 of the lower mold 20 but based on the relative relationship between the transport arm 60 and the molding material 50. Therefore, for example, when the molding surface 21 is not a concave surface having a predetermined curvature or more, there is a restriction around the molding surface 21 and a jig or the like cannot be used, or the molding die is assumed to be transferred. Even if it is difficult or inefficient to correct the position of the molding material on the molding surface, such as when a jig cannot be placed, the molding material is accurately supplied to the center of the molding surface of the mold. Arrangement can prevent deterioration of surface accuracy due to uneven thickness and uneven press load, and a highly accurate optical element can be manufactured.

  While the present invention has been described with reference to the preferred embodiment, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. .

  TECHNICAL FIELD The present invention relates to a technical field in which an optical element is manufactured by press-molding a molding material such as glass using a pair of upper and lower molds subjected to precision processing without requiring post-processing such as polishing of a molding surface. Can be widely applied to.

It is explanatory drawing which shows process (1)-(4) in embodiment of the manufacturing method of the optical element which concerns on this invention, and shows a part of positioning process using 1st embodiment of the positioning device which concerns on this invention. Yes. It is explanatory drawing which shows process (5)-(7) in embodiment of the manufacturing method of the optical element which concerns on this invention, and shows a part of positioning process using 1st embodiment of the positioning device which concerns on this invention. Yes. It is explanatory drawing which shows a part of positioning process using 2nd embodiment of the positioning device which concerns on this invention. It is a schematic plan view which shows embodiment of the mold press molding apparatus which concerns on this invention. It is a schematic sectional drawing which shows an example of the mold press shaping | molding die suitably used for this invention. It is explanatory drawing which shows process (8)-(11) in one Embodiment of the manufacturing method of the optical element which concerns on this invention. It is explanatory drawing which shows process (12)-(15) in one Embodiment of the manufacturing method of the optical element which concerns on this invention. It is explanatory drawing which shows process (16)-(18) in one Embodiment of the manufacturing method of the optical element which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioning device 2 Receiving part 3 Opening part 5 Heating means 6 Pit hole 10 Upper mold 20 Lower mold 50 Molding material P1 Extraction / insertion chamber P2 First heating chamber P3 Second heating chamber P4 Third heating chamber P5 Press chamber P6 First gradual Cold room P7 Second slow cooling room P8 Rapid cooling room P9 Disassembly / assembly part P10 Positioning part

Claims (9)

A molding material is supplied to a mold by a conveying means, and is a method of manufacturing an optical element for press molding,
When supplying the molding material to the mold,
The molding material is placed on a positioning device, an air flow is ejected from the positioning device to correct the position of the molding material , and then the molding material is sucked to fix the molding material on the positioning device. By
After the relative positioning of the molding material and the conveying means,
A method for producing an optical element, wherein the molding material is supplied to the molding die by the conveying means.   2. The method of manufacturing an optical element according to claim 1, wherein the molding material is formed on a receiving die by flowing or dropping molten glass, and has a shape covered with a convex curved surface. .   The method for manufacturing an optical element according to claim 1, wherein the molding material is preheated on the positioning device.   The mold containing the molding material is transferred to a plurality of processing chambers including a heating chamber, a press chamber, and a cooling chamber, and sequentially subjected to processing including heating, pressing, and cooling, and then accommodated in the molding die. The method for manufacturing an optical element according to claim 1, wherein the molding material is press-molded. A mold press molding apparatus for press molding a molding material,
A pair of molds having opposing molding surfaces;
Conveying means for supplying the molding material to the mold;
A positioning device for relatively positioning the molding material and the conveying means;
The positioning device has a receiving portion on which the molding material is placed , and blows an air current from an opening provided on the placing surface of the receiving portion to float the molding material on the receiving portion. The position is corrected, and then the atmosphere is sucked to make the inside of the opening have a negative pressure so that the molding material is fixed on the receiving portion, so that the molding material and the transporting unit are relative to each other. press-molding apparatus according to claim to Rukoto the Do positioning. A positioning device that relatively positions the molding material and a conveying unit that supplies the molding material to the molding die when the molding material is supplied to the molding die and press-molded.
The molding material has a receiving portion to be placed, and the air flow is jetting from the placement opening provided on surface of the receiving portion, to correct the position by floating the forming material on the receiving unit, then, by the negative pressure of the opening portion by sucking the ambient gas, by securing the molding material on the receiving part, you and the forming material, the relative positioning of the transport means A positioning device characterized by that.   The positioning device according to claim 6, wherein the mounting surface of the receiving portion has a concave curved surface.   The positioning device according to claim 6, wherein a drop hole having an inner diameter slightly larger than an outer diameter of the molding material is provided so as to surround the receiving portion.   The positioning device according to any one of claims 6 to 8, wherein a heating means is installed around the receiving portion.

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