JPH01183423A - Optical element production device - Google Patents

Abstract

PURPOSE:To suppress variability of temperature distribution of molds and to carry out press molding at the best pressing temperature, by pushing and transferring plural stands having placed optical element molds in a heating process while bringing the stands into contact with each other and setting a part to avoid influence of heat transfer from other members to the stands. CONSTITUTION:An optical element production device consisting of a heating process to heat optical element molding materials 15 and a pressing process to press molding the materials 15 having passed the heating process is equipped with the following constitution. Namely, plural stands 11 having placed molds 13 and 14 to press mold the materials 15 are pushed and transferred in the heating process while being brought into contact with each other and each stand 11 is equipped with a part (e. g., cut 30 at the outer peripheral part) to avoid influence of heat transfer from other members.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an optical element press molding apparatus, and an optical element manufacturing apparatus that can continuously manufacture high precision optical elements without the need for post-processing after press molding. Regarding.

(Prior art) In recent years, optical elements with high-precision optical surfaces that do not require post-processing such as grinding or grinding have been developed by press-molding optical element materials placed in molds with a predetermined surface accuracy. Methods have been developed to mold the elements.

An optical element molding method using such a press molding method and suitable for continuous molding of optical elements is disclosed in, for example, Japanese Patent Laid-Open No. 59
As shown in Japanese Patent Application Laid-Open No. 150728 or JP-A No. 61-26528, a material for molding an optical element is housed and placed in a mold, and the material is held in the mold while being connected to a heating section and molding. The material is sequentially introduced into a continuous furnace that has a heating section and a cooling section, and after heating and softening the material together with the mold in the heating section to a temperature at which it can be molded, it is pressed in the forming section and then pressed in the cooling section. Cooling the molding material to below the glass transition point while maintaining the state of the mold at the time,
This process includes the step of removing the molded product from the mold afterward.

(Problem to be Solved by the Invention) However, during such a process, in the process in which the material for molding an optical element is heated to a temperature at which it can be molded, the material for molding is heated in the mold to a surface cap of the mold. Since they are in contact with each other or in close proximity to each other, there is a problem in that the molding material and the surface of the mold react with each other during press molding, causing the surface of the mold to be attacked. In particular, when the molding material for optical elements is a lead-containing glass material, the distance between the glass material and the mold surface is l■
Even in a non-contact state such as the intestines, after heating, the lead component in the glass material adheres to the mold surface and the mold surface is rapidly corroded, resulting in a significant decrease in the surface precision of the mold.

In order to solve these problems, the present inventors have aimed to prevent erosion of the mold by the glass component during press molding, maintain the durability and surface precision of the mold, and create a high-precision optical element. We have already proposed an optical element manufacturing apparatus that can continuously and rapidly manufacture optical elements.

In this type of optical element manufacturing apparatus, when a mounting table a on which a molding die for press-molding an optical element molding material is placed passes through a heating process, the mounting table is heated at the same time as the molding die. The temperature rises and affects the temperature rise of the mold.

Then, when each tL mounting table moves while touching each other,
It is affected by heat transfer from other adjacent mounting tables and guide rails that guide the mounting table. However, at this time, if the contact state with respect to other adjacent mounting tables or guide rails is different on each mounting table, uneven heat distribution will occur on each mounting table, and the temperatures of the respective molds will be different. Even in the same mold, there is a problem that the temperature distribution is partially different. For this reason, there arises a problem that the I&-shaped mold is heated to a temperature higher or lower than a predetermined pressing temperature, or uneven heat distribution occurs, making it impossible to provide good pressing temperature conditions.

As shown in FIG. 8, the above-mentioned case where uneven heat distribution occurs on the mounting table means that the mounting table 41 that is guided and transferred by the guide rail 40 is not connected to the other 88 units or the guide rail 40.
This refers to a case where the contact situation differs due to, for example, the adhesion of dust or machining accuracy, and the contact situation is different in the same figure.

The diagonal lines drawn on the pallet 41 schematically indicate the areas where the pallet is affected by heat transfer from other pallets and the guide rail 40, and the temperature of this shaded area is higher than that of other areas. It shows the situation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical element manufacturing apparatus that can suppress variations in the temperature distribution of a mold and perform press molding at the best press temperature. .

(Means for Solving the Problems) In order to solve the above-mentioned problems, the optical element manufacturing apparatus of the present invention includes a heating step of heating a material for forming an optical element, and a pressing of the material that has passed through the heating step. In the optical element manufacturing apparatus equipped with a press step for forming the material, a plurality of mounting tables on which molding molds 17 for press-molding the material are placed are extruded and conveyed while contacting each other during the heating step; Each mounting table is characterized by having an avoidance part that avoids the influence of heat transfer from other adjacent members. (
(Function) In the present invention, an avoidance portion is provided to avoid the influence of heat transfer from other members adjacent to each mount a. Examples of this avoidance part include providing a notch on the outer periphery of the mounting table, or providing a protrusion on the outer periphery to reduce the contact surface with other parts, or machining the mounting table. Alternatively, a structure may be adopted in which a heat insulating material is pasted on the outer periphery of the mounting table without applying any process, or a notch as described above is provided and a heat insulating material is pasted to this notch. The avoidance portions provided on the four mounting tables can avoid the influence of heat transfer from other adjacent members, and can prevent variations in the temperature distribution of the mold.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic plan view of the entire device, FIGS. 2 to 6 are sectional views of each part of the device in the order of steps, and FIG. 17 is a perspective view showing the main parts of this embodiment.

The overall configuration of this device is as follows: material intake chamber 1. Heating section 2, material transfer section 3. Press section 5. Annealing section 6 and molded product removal chamber 7
It consists of 6 material intake chambers 1, heating section 2. The material transfer section 3 and the press section 5.

An annealing section 6 is disposed on the same line and in parallel with these lines.

A first transfer chamber 21 is configured near the entrance of the heating section 2,
This first transfer chamber 21 is provided with the material intake chamber l. A second transfer chamber 22 is configured near the outlet of the press section 5, and is used for slow cooling. A third transfer chamber 23 is configured at the entrance of $6, and these second and third transfer chambers are connected by a transfer path 25. Further, a fourth transfer chamber 2 is provided near the outlet of the slow cooling section 6.
4, this fourth transfer chamber 24 is provided with a molded product removal chamber 7, and the fourth transfer chamber 24 and the first transfer chamber 2 are
1 through a circuit 26. With such a configuration, the present molding apparatus has a molding chamber 59 that forms a continuous path.

11 is a pallet that can be transported inside the molding chamber, and is made of 5US303 or 5US303, which has excellent thermal conductivity and heat resistance.
US304 is suitable. Notches 30 are provided on each of the four outer peripheral surfaces of the pallet. These notches are provided in the same position and size for each pallet 11, and the heat transfer conditions of each pallet 11 are formed in the same manner.

Also, on the same bar) 11 is a material table 12 and an upper y for press forming. 113 and a lower mold 14 are arranged with a constant interval, and the press molding surfaces of the upper mold 13 and the lower mold 514 have mirror surfaces 13a and 1 for molding the optical element functional surface, respectively.
4a has been applied.

A plurality of bars 11 are placed on a guide rail 28 provided in the molding chamber 59, and are moved on the guide rail 28 in a state in which they are in contact with each other without being pressed against each other by the extrusion operation of the cylinder, which will be described later.

According to such a valve (11), compared to a normal valve (11) whose outer peripheral surface is formed flat.

The contact area of the pallet 14 with other pallets or the guide rail 28 is significantly small and is less susceptible to heat transfer from other members, thus causing uneven heat distribution in the inner body of the pallet 11. Also, uneven heat distribution is less likely to occur on the upper and lower molds 13, 14 and the material mounting table 12 placed on this pallet.

As a means for transferring the pallet 11 into the molding chamber, as shown in FIG. It will be done. Second
The transfer chamber 22 is provided with a drawer cylinder 52 and an extrusion cylinder 53, and the pallet 1 that has been moved to the press section 5 by the drawer cylinder 52 is pulled out to the second transfer chamber 22, and the extrusion cylinder 53
The pallet 1 that was moved to the third transfer chamber 23 is transferred to the third transfer chamber 23.
It is pushed out to . The third transfer chamber 23 is provided with an extrusion cylinder 54, and the extrusion cylinder 54 pushes the valve 11 that has been moved to the third transfer chamber 23 to just before the fourth transfer chamber 24. The fourth transfer chamber 24 is provided with a drawer cylinder 55 and a push-out cylinder 56 , and the valve 11 that has been moved to just before the fourth transfer chamber 24 is pulled out to the fourth transfer chamber 24 by the drawer cylinder 55 . , pallet t by the extrusion cylinder 56
t is again pushed out to the first transfer chamber 21. Thus, the bar 11 is transferred to each process by the extrusion or pull-out operation of these cylinders and moves within the molding chamber 59 of the apparatus.

Next, each part of the molding chamber 59 will be explained.

Heating section 2. A heater 57 is provided in the furnace body corresponding to the material transfer section 3 and the press section 5, and a heater 58 is provided in the furnace body corresponding to the slow cooling section 6. Each of these heaters is used for heating the material 15 and cooling the molded product 18 after pressing.

The upper mold 13 and the lower mold 1 are placed in the material transfer section 2 and the molded product removal chamber 7.
4. Lifting hand 1 for lifting at required intervals.
6.20 (FIGS. 4 and 6), the lifting hand is moved up and down by a lifting means (not shown). Furthermore, the material transfer section 3 includes a material loading table 1 in the material intake room l.
A suction finger 4 is provided for transferring the material 15 placed on the upper mold 13 onto the lower mold 14 (FIG. 4). The suction hand is operated and the material 15 is transferred to a predetermined position on the lower die 14. This suction finger 4 is used when transferring the material 15 as described above.
It is configured to operate with a constant stroke corresponding to the distance between the material placement part 12 of the bar 11 and the lower mold 14 so that the material is placed at a predetermined position on the lower mold 14 accurately. There is. In addition, there is a material intake chamber 1 and a molded product extraction chamber 7.
To do this, place the material 15 on the stand 12, or
A suction finger 19 is provided for taking out the mold 8 from the upper mold 13 (FIG. 6).

The press section 5 is provided with a press rod 17 for pressing the upper die 13 during press molding (FIG. 5).

In this device, the inside of the molding chamber 59 is evacuated and then non-oxidizing gas such as N2 gas is supplied to the inside of the molding chamber 59 to prevent the mold materials forming the upper mold 13 and the lower mold 14 from being oxidized at high temperatures. Needs to be filled and the above lifting hand 16. Suction finger 4.19, press rod 17, etc. and molding chamber 5
The sliding portion with the outer wall of 9 is sufficiently shielded to ensure airtightness within the molding chamber.

Next, the operation of the apparatus configured as described above in each step will be explained according to the overall plan view of FIG. 1 and the order of the press forming steps shown in FIGS. 2 to 6. Figure 2 is material 1
The barre 11 shown in FIG. 1 is made of 5US303 or 5US304.

First, as described above, in order to prevent oxidation of the mold materials of the upper and lower molds 13 and 14, the inside of the molding chamber 59 is evacuated to I Fill with non-oxidizing gas.

Next, the heaters 57 and 58 are energized to raise the temperature of the molding chamber to a predetermined value. After the temperature has been raised, the material 15 is passed through the atmosphere conversion chamber in the material intake chamber 1, and the bar 11 in the material intake chamber 1 is placed on the mounting table 12 using the suction finger 19 as shown in FIG. .

Next, as mentioned above, the extrusion cylinder 51°53.54
．． 55 and the drawer cylinders 52 and 56 (bars) 11 are sent from the molded product take-out chamber 7 to the material intake chamber 1.
Place it on 2. By repeating these actions repeatedly.

When the material 15, upper mold 13 and lower mold 14 supplied to the first pallet 11 are heated to the temperature required for press forming near the material transfer section 3, the material 15 is transferred to the lower mold 14. At this time, the material 15 and the upper mold 13
It is desirable that the material 15 is heated to approximately the same temperature as the upper mold 13 or the lower mold 14. By doing so, the temperature of the material 15 after transfer will not change depending on the temperature of the upper mold 13 or the lower mold 14, and an optimal press can be performed. Press molding can be performed under temperature conditions. Then, in the material transfer section 3, the upper die 13 is lifted up by the lifting hand 16.

Next, the material 15 is suctioned by the suction fingers 4 and transferred onto the lower mold 14. Thereafter, the pallet 11 on which the transfer of the materials 15 has been completed is moved to the position of the press section 5. At this time, the lifting hand 16 is removed and the press rod 17 is activated to press the upper fi 13 with a predetermined press pressure to perform press forming on the material 15.
The pressing of the press rod 17 is released, and the pallet 11 is moved from the press section 5 to the second transfer chamber 22 while the upper mold 13 maintains its state during pressing. Furthermore, this bar 11 is transferred to the third transfer chamber 23 via the transfer path 25.

Next, the pallet 11 is pushed out in the direction of the annealing section 6 of the molded product by the extrusion cylinder 54, but since other valves 11 are arranged in front of the moving direction, the pallet 11 is pushed out as described above. While this operation continues, the upper mold 13 and the lower mold 1
The molded product 18 held in the annealing section 6 passes through the annealing section 6, where it is gradually cooled. It will be done.

Next, the lifting hand 20 is operated to remove the upper mold 13, and then the molded product 18 is taken out by the suction fingers 19. Then, the pallet 11 from which the molded products have been taken out is transferred to the material intake chamber 1 via the circulation path 26, and the above-described operations are repeated again to continuously manufacture molded products 18.

Incidentally, the table below shows the results of press molding with and without the notch 30 provided in the bar 11.

In addition, in the table above, the model number in the column "With notch" and "
The mold numbers in the column "Without notches" indicate molding molds placed on the pallet 11 in the same condition on the rail 28, and in each column, the cases with and without notches are compared. be.

As is clear from this table, d! Even when the mold was placed in the mold, there was no significant change in mold temperature in the case with a notch, and the press molding results were good, but in the case without a notch, a significant change occurred. This results in insufficient pressing or damage to the molded product.

Therefore, according to this embodiment, it is possible to suppress variations in the temperature distribution of the mold and perform press molding in a favorable press temperature state.

Further, according to this embodiment, the material 15 is placed on the material cutting table 12 and separated from the upper mold 13 and the lower mold 14 until just before press forming, so that the material 15 and the molds 13, 14 are separated from each other.
Reaction with is prevented. Of course, this does not prevent the reaction between the material 15 and the mold 13.14 from occurring during press molding and subsequent slow cooling, but no reaction occurs during press molding when the temperature is lowered after press molding. This, in combination with the above-mentioned effect of shortening the reaction time, is beneficial for improving the durability of the mold.

Furthermore, the apparatus of this embodiment is configured to transfer materials on the same pallet.

No relative positional change occurs between the material ti table 12 and the mold,
The positioning accuracy of the suction finger 4.19 in handling etc. can be easily obtained, and the suction finger 4.19 is
Since the pallet 9 is heated at the same time as the pallet 11, errors in handling positioning accuracy due to thermal expansion are less likely to occur.

According to the apparatus of this embodiment, the durability of the mold is guaranteed as described above, and erosion of the molding surface is prevented.
The specularity of the molded surface is maintained for a relatively long period of time, so
Suitable for continuous production of high-precision optical elements.

(Effects of the Invention) As explained above, according to the present invention, by providing the avoidance portion for avoiding the above-mentioned heat transfer on the mounting table of the mold, variations in the temperature distribution of the mold can be suppressed. Press molding can be performed under favorable press temperature conditions.

Therefore, the apparatus of the present invention is suitable for continuously manufacturing high-precision optical elements by press molding.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of the entire device related to an embodiment of the device of the present invention, FIGS. 2 to 6 are sectional views of each part in the order of steps, and FIG. 7 is a perspective view showing the main parts of this embodiment. and
FIG. 8 is a diagram for explaining that variations occur in each a1 table due to differences in the state in which each mounting table contacts other members. 2...Heating section 3...Material transfer section 5...Press section 6...Annealing section 11...Pallet 12...Material mounting table 13...Upper die 14...Lower Mold 30... Notch 59... Molding chamber

Claims (2)

[Claims] (1) In an optical element manufacturing apparatus that includes a heating step of heating a material for forming an optical element and a press step of press-molding the material that has passed the heating step, a mold for press-molding the material is installed. A plurality of placed mounting tables are extruded and conveyed while contacting each other during the heating process, and each of the mounting tables has an avoidance part that avoids the influence of heat transfer from other adjacent members. Optical element manufacturing equipment. (2) The optical element manufacturing apparatus according to claim 1, wherein the avoidance section is constructed by providing a notch on the outer periphery of the mounting table.