JPH0474724A - Apparatus for forming optical element - Google Patents

Abstract

PURPOSE:To enable the production of a pressed lens having high surface accuracy and surface roughness by providing a positioning member to be inserted into a transfer table in a specific manner and a positioning member fitted on a lower mold through an elastic member in a state movable in vertical direction. CONSTITUTION:A transfer table 7 holding a glass gob 6 is transferred between a lower mold 1 and an upper mold 2 with a table-transfer arm 8. A positioning member 3 constructed in such a manner as to get interference fit with the lower mold 1 with heat is inserted into the transfer table 7 by lifting the lower mold 1 to effect the positioning in horizontal direction. When the lower mold 1 is further lifted, another positioning member 4 held with an elastic member 5 is brought into contact with the lower part of the transfer table 7 and the glass gob 6 is lifted together with the transfer table 7 from the table-transfer arm 8 until the glass gob 6 is brought into contact with the upper mold 2. The positioning member 4 is lowered relative to the lower mold by the deformation of the elastic member 5 to press the glass gob 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical element molding apparatus for manufacturing a press lens having high surface accuracy and high surface roughness.

[Prior Art] Conventionally, the following inventions have been disclosed as molding apparatuses for this type of optical element.

For example, in the invention described in Japanese Patent Application Laid-open No. 64-24029, the glass material is It is press-molded separately from the conveying member. Then, an invention has been proposed in which the collar and the conveying member are provided with a fitting portion and brought into contact with each other, thereby positioning the conveying member.

Further, in the invention described in JP-A-1-270529, a heat insulating material such as ceramic or the like is provided on the outer periphery of either the upper mold or the lower mold.

An invention has been proposed in which positioning is also possible by providing a tapered portion or the like on the outer periphery of this heat insulating material and fitting it with a conveying member.

[Problem to be solved by the invention] However, the prior art has the following problems.

That is, in the invention described in Japanese Patent Application Laid-open No. 64-24029, in a device in which a collar that slidably fits into a mold and a conveying member are provided with a fitting part and brought into contact with each other for positioning, the collar is positioned against the mold. In order to slide without prying, a clearance of approximately 0.01 m is required between the collar and the outer periphery of the mold. However, by providing this clearance, positioning accuracy deteriorates by the amount of clearance.

Further, in the invention described in JP-A-1-270529, - When the outer diameter of the glass material is relatively large for boat fishing,
By using a conveying member whose coefficient of linear expansion is smaller than that of the glass material, a clearance is created between the outer diameter of the glass material and the inner diameter of the conveying member at room temperature, resulting in an interference fit when heated. Thus, the outer diameter of the glass material and the inner diameter of the conveying member can be set. As a result, the glass material and the conveying member are brought into tight fit during heating and are lifted at the same time, so that it is possible to prevent the press lens from falling into the separated conveying member when the mold is released after press molding. Therefore, scratches and the like will not occur on the press lens.

Further, at room temperature, the clearance created makes it easier to take out the press lens from the conveyance member.

However, the outer diameter of the glass material is small (φ5- or less).
In this case, considering the workability of loading and unloading glass materials into and out of the conveying member, the clearance is 0.02 m.
However, due to the small diameter, even heating will not result in an interference fit. Therefore, the glass material is press-molded separately from the conveying member. Therefore, after press molding, the press lens is held in an inclined state, making it difficult to take out the press lens from the conveying member after cooling. There is also the problem that the press lens may be scratched due to falling.

Therefore, the present invention was developed in view of the above problems.
The purpose of the present invention is to provide an optical element molding device that can improve the positioning accuracy of the glass material and the conveying member, improve workability when taking out the press lens, and eliminate defects in the press lens due to scratches, etc. do.

[Means and effects for solving the problem] The present invention involves interposing a heated and softened glass material via a conveyance table between molding molds consisting of an upper mold and a lower mold disposed facing each other on the same axis. In an optical element molding apparatus that performs press molding, the positioning device is formed of a material having a linear expansion coefficient lower than the linear expansion coefficient of the lower mold, is externally fixed to the upper part of the lower mold, and is inserted internally into the conveyor table. and a positioning member fitted onto the lower die so as to be vertically movable via an elastic member.

FIG. 1 is a conceptual diagram of an optical element molding apparatus according to the present invention.

Reference numeral 2 denotes a lower mold which is held movable up and down, and an upper mold 2 is disposed above the lower mold 1 and facing on the same axis. Lower mold 1
A positioning member 3 made of a material having a coefficient of linear expansion equal to or lower than that of the lower mold 1 is fitted onto the upper part of the lower mold 1, and the lower mold 1 and the positioning member 3 are configured to form an interference fit during heating. ing. Further, a positioning member 4 is fitted onto the lower mold 1 so as to be movable up and down, and is always held upward by an elastic member 5 surrounding the outer periphery of the lower mold 1.

In the optical element molding apparatus having the above-described configuration, first, the conveyance table 7 on which the glass material 6 is placed is conveyed between the lower mold 1 and the upper mold 2 by the conveyance table moving arm 8 . When the lower mold 1 rises, the positioning member 3, which is configured to form an interference fit with the lower mold 1 during heating, is inserted into the inside of the conveyor table 7 and horizontally positioned. Furthermore, when the lower mold 1 rises, the positioning member 4 held by the elastic member 5 moves onto the conveyor table 7.
glass material 6 from the conveyor moving arm 8.
and the transport platform 7 are lifted together. Then, when the lower mold 1 further rises, the glass material 6 comes into contact with the upper mold 2. At this time, the positioning member 4 moves the lower die 1 due to the deformation of the elastic member 5.
The glass material 6 is press-molded. After press forming, the lower die 1 is lowered, and the press lens and the conveyance table 7 return to the conveyance table moving arm 8 as one body.

〔Example〕

Hereinafter, embodiments of the optical element molding apparatus according to the present invention will be described in detail with reference to the drawings.

(First Embodiment) Figs. 2 to 4 show a first embodiment of the present invention, in which Fig. 2 is a longitudinal sectional view, Fig. 3 is a sectional view of the main part, and Fig. 4 is a portion of the positioning member. It is an enlarged sectional view.

11 is a molding chamber, and this molding chamber 11 is composed of a cover 13 erected on the upper surface of a lower base 12 and an upper base 14 placed on the upper part of this cover 13, and the molding chamber 1 is heated.
1 is configured to be maintained in an N2 atmosphere. An upper die support 15 is fixed to the lower center surface of the upper base 14. A cylindrical upper mold heater 16 is located in the center of the upper mold support 15.
are fitted and fixed. The upper mold 2 is fixed to the lower surface of the upper mold support 15 by an upper mold holding ring 17. A mold release ring 18 is loosely fitted onto the outer periphery of the upper mold 2 and is held so that it can move up and down along the upper mold 2, and can be moved up and down by a drive device (not shown) provided outside the molding chamber 11. It is configured.

A main shaft 19 passing through a hole 12a formed in the center of the lower heath 12 is held by a drive device (not shown) provided below the molding chamber 11 so as to be movable up and down. A lower mold support 20 is placed on the upper part of the main shaft 19, and a cylindrical lower mold heater 21 is fitted and fixed in the center of the lower mold support 20. The lower mold 1 is fixed to the upper surface of the lower mold support 20 by a lower mold holding ring 22.

A positioning member 3 made of a material having a linear expansion coefficient equal to or lower than that of the lower mold 1 is fitted onto the upper part of the lower mold 1, so that the lower mold 1 and the positioning member 3 are tightly fitted during heating. It is composed of The positioning member 3 positions the conveyor table 7 in the horizontal direction, and has 8 parts 3b on the upper outer periphery between the upper surface of the positioning member 3 and the fitting part 3a so that it can be easily inserted and fitted inside the conveyor table 7. and a tapered portion 3C are formed. A positioning member 4 for regulating the vertical position of the conveyor table 7 is fitted onto the lower mold 1 so as to be movable up and down.

An elastic member holding ring 23 is fixed to the lower part of the outer periphery of the lower mold 1, and an elastic member 5 that surrounds the outer periphery of the lower mold 1 is provided between the elastic member holding ring 23 and the positioning member 4. The outer periphery of the elastic member holding ring 23 is threaded, and a positioning member 24 that regulates the vertical position of the positioning member 4 is screwed therein. This screw allows the height of the positioning member 24 to be adjusted. The positioning member 24 is always pushed upward by the elastic member 5, but its position can be regulated by the lower upper surface of the positioning member 4 coming into contact with the upper and lower surface of the positioning member 24, except when pressing the glass material. It is configured as follows.

In the apparatus configured as described above, first, the conveyance table 7 on which the glass material 6 is placed is conveyed by the conveyance table moving arm 8 to a heating furnace (not shown) provided outside the molding chamber 11, and is heated to a predetermined temperature. Heat for an hour. Thereafter, the conveyance table 7 is conveyed between the lower mold 1 and the upper mold 2 by the conveyance table moving arm 8.

Then, the main shaft 19 rises, and the 8th section 3b of the positioning member 3 comes into contact with the inside of the conveyance table 7. Furthermore, as the main shaft 19 rises, the inside of the conveyor table 7 slides along the tapered part 3c, and finally fits into the fitting part 3a. This results in
The transport table 7 is positioned in the horizontal direction. The positioning member 4 is restricted by the force of the elastic member 5 and the positioning member 24 to a position where the glass material 6 of the conveyance table 7 does not come into contact with the lower mold 1 . Therefore, when the main shaft 19 further rises, the conveyance table 7 on which the glass material 6 is placed W& is lifted from the conveyance table moving arm 8 by the positioning member 4 held by the force of the elastic member 5.

As a result, the glass material 6 first comes into contact with the upper mold 2. When the main shaft 19 further rises, the positioning member 4 slides along the outer periphery of the lower mold 1 due to the deformation of the elastic member 5 and descends relative to the lower mold 1.

The glass material 6 is then press-molded. After press forming, the main shaft 19 descends. At the same time, the release ring 18 also descends and comes into contact with the press lens and the conveyance table 7, whereby the press lens and the conveyance table 7 are released from the upper mold 2. In addition, when releasing the press lens from the lower mold 1, the main shaft 1
9 is further lowered, via the conveyor table 7 and the conveyor table moving arm 8.

According to this embodiment, since the lower mold 1 and the positioning member 3 are configured to form an interference fit during heating, the clearance between the lower mold 1 and the positioning member 3 can be eliminated. Therefore, the positioning of the conveyor table 7 is made more precise, and it becomes possible to mold a press lens having high surface accuracy and high surface roughness.

Furthermore, even if a clearance is created between the glass material 6 and the conveyance table 7 during heating, the glass material 6 and the conveyance table 7
is lifted up from the transfer table moving arm 8 and press-molded in one piece, so when the mold is released, only the press lens tilts and falls with respect to the transfer table 7, and the press lens cannot be taken out from the transfer table 7. This eliminated the occurrence of scratches on the press lens due to falling, improving workability and improving the quality of press lens external fitting.

Furthermore, since the positioning member 4 is brought into contact with the positioning member 24 by the force of the elastic member 5 and the height direction is regulated,
The processing precision required for the elastic member 5 has been relaxed, and assembly and height adjustment have become easier.

(Second example) FIG. 5 is a partially enlarged sectional view of the main part.

This embodiment differs from the first embodiment in that a tapered portion 1a is formed at the tip of the lower mold 1, and that a tapered portion 7a is formed on the lower surface of the transfer table 7 to match the shape of the tapered portion 1a. However, other components are the same, and the same components are designated by the same numbers and their explanations will be omitted.

The operation is similar to that of the first embodiment, and the explanation of the operation will be omitted.

According to this embodiment, by providing the lower mold 1 and the conveyor table 7 with the tapered portions 1a and 7a, respectively, it is possible to further increase the area of the portion of the lower mold 1 that comes into contact with the glass material 6.

Furthermore, the durability of the lower mold 1 is improved by increasing the strength of the upper part of the lower mold 1.

(Third example) FIG. 6 is a half-cut sectional view of the main part.

This embodiment is based on the positioning member 24 in the second embodiment.
is abolished, and instead, the positioning member 4 is locked to the positioning member 3 so as to be vertically movable. Furthermore, the structure differs in that the lower part of the outer periphery of the positioning member 3 is threaded, and an elastic member holding ring 23 with a threaded inner periphery is screwed into the structure. Components are given the same numbers and their explanations will be omitted.

The positioning member 3 regulates the horizontal position of the transport platform 7. Due to the force of the elastic member 5, the positioning member 4 comes into contact with the stepped portion 3a of the positioning member 3, and its position in the height direction is regulated. Further, the elastic member holding ring 23 is attached to the positioning member 3
The elastic member 5 is held by screwing into the lower part of the outer periphery of the elastic member 5. The other configurations and operations are the same as those of the second embodiment, and explanations of the configurations and operations will be omitted.

According to this embodiment, the same effects as those of the second embodiment can be obtained, and since the number of parts of the positioning member is reduced, the assembly of the positioning member becomes easier and work efficiency can be improved.

〔Effect of the invention〕

As explained above, according to the optical element molding apparatus according to the present invention, the lower mold and the positioning member are configured to form an interference fit during heating, so that the clearance between the lower mold and the positioning member can be reduced. I was able to get rid of it. Therefore, the positioning of the conveyor table has become more accurate, and it has become possible to mold a press lens with high surface accuracy and high surface roughness.

In addition, even if there is a clearance between the glass material and the conveyor table during heating, the glass material and the conveyor table are lifted and press-molded together by the conveyor table moving arm, so when the mold is released, only the press lens The press lens will not be able to be taken out from the conveyor table due to the lens falling at an angle to the conveyor table, and there will be no scratches on the press lens due to the fall, which improves work efficiency and improves the quality of the press lens external fitting. I was able to improve.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of an optical element molding apparatus according to the present invention, Figs. 2 to 4 show the first embodiment, Fig. 2 is a longitudinal sectional view, and Fig. 3 is a sectional view of main parts. , FIG. 4 is a partially enlarged sectional view of the positioning member, FIG. 5 is a partially enlarged sectional view of the main part showing the second embodiment, and FIG. 6 is a half-cut sectional view of the main part showing the third embodiment. be. ...Lower die...Upper die 4.24...Positioning member...Elastic member...Glass material...Transportation platform...Transportation platform moving arm...Molding chamber 2...Lower heath 3...・Cover 4...Upper head 5--Upper die support 6...Upper die heater 7...Upper die holding ring 8...Release ring 9-・Main shaft 0...Lower die support 1・- Lower die heater 22 - - Lower die holding ring 23 ... Elastic member holding ring

Claims (1)

[Claims] (1) In an optical element molding apparatus that performs press molding by interposing a heated and softened glass material via a conveyor table between molding molds consisting of an upper mold and a lower mold disposed facing each other on the same axis, the above-mentioned a positioning member formed of a material having a coefficient of linear expansion equal to or lower than the coefficient of linear expansion of the lower mold, which is externally fixed to the upper part of the lower mold and inserted into the transfer table; 1. A molding device for an optical element, comprising a positioning member externally fitted so as to be movable up and down.