JPH0761825A - Molding machine for optics - Google Patents

Abstract

PURPOSE:To continuously mold optics having a stable quality low in scattering. CONSTITUTION:Sending in of an optical material and the residence time of it in a heating passage are controlled by utilizing pulses of a molding cycle generated by a timer circuit so as to make the time for heating the optical material constant. At the same time, the pressing time is controlled thereby, thus stabilizing the quality of the optics in continuous molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus for pressing an optical material to form an optical element.

[0002]

2. Description of the Related Art An optical element molding apparatus has a structure in which an optical material is held by a carrier, heated and softened in a heating furnace, and then pressed by a mold composed of an upper mold and a lower mold which are coaxially opposed to each other. Are used. 7 and 8 show the above-described operation by combining the mold driving device described in JP-A-62-167227 and the optical material conveying device described in JP-A-62-191430. A conventional molding apparatus that enables the above is shown.

A heating furnace 31 and a slow cooling furnace 36 are arranged on the frame 22, and the heating furnace 31 and the slow cooling furnace 3 are arranged.
An upper die 11 and a lower die 12 that press the optical material 61 to form an optical element 62 are arranged between the six. The heating furnace 31 includes the optical material 6 held by the carrier 51.
1 is heated while being transported, and the slow cooling furnace 36 is for gradually cooling while transporting the optical element 62 that is molded and held by the carrier 51. Therefore, as shown in FIG. 8, the heating furnace 31 and the slow cooling furnace 36 are formed into a long tubular shape, and the carrier 51 holding the optical material 61 is conveyed in the heating furnace 31 in the direction of arrow A. The caterpillar 43, on the other hand, is provided in the annealing furnace 36 with the optical element 62 after molding.
Ejecting tracks 44 for transporting the carrier 51 holding C in the direction of arrow C are arranged. In FIG. 8, 43a and 44a are installation holes formed in the supply caterpillar 43 and the discharge caterpillar 44 at equal intervals in order to fix the carrier 51 in place.

The upper mold 11 and the lower mold 12 face each other while being attached to the respective supports 13 and 14, and the support 13 of the upper mold 11 is attached to the upper base 15 and the lower mold 12.
The support bodies 14 are held by holding shafts 17, respectively.
In addition, the upper mold 11 and the lower mold 12 are each heater 3
It is heated to a predetermined temperature by 3, 34. On the other hand, the holding shaft 17 is extended in the vertical direction, and the extended end portion is bent in one direction, and this bent portion is connected to the cylinder 18. The cylinder 18 is connected to a sliding table 19 that moves in the vertical direction, and the sliding table 19 is connected to a vertical movement motor 21 via a ball screw 20. In such a structure, the vertical shaft motor 21 is driven to move the holding shaft 1 through the sliding table 19 and the cylinder 18.
7 moves up and down, which moves the lower mold 12 up and down,
The optical material is pressed and taken out. In this case, the drive of the vertical motion motor 21 is controlled by the mold drive control circuit 1.

In FIG. 7 and FIG. 8, 32 is a heating furnace 3.
The first heating heater is provided in communication with the outlet 31b of No. 1 and the reference numeral 35 is a slow cooling start heater provided in communication with the inlet 36a of the slow cooling furnace. In addition, the inlet 3 of the heating furnace 31
1a and an outlet 36b of the outlet 36a of the annealing furnace 36 are provided with a carrier carrier arm 41 for supply and a carrier carrier arm 42 for carry-out so as to intermittently advance and retreat in a direction indicated by an arrow B in FIG. The carrier carrier arm 41 for supply is the carrier 51 that has reached the end of the heating furnace 31.
Is conveyed from the furnace 31 to the molding position 3 between the upper mold 11 and the lower mold 12. On the other hand, the carrier carrier arm 42 for discharging carries the carrier 51 at the molding position 3 into the annealing furnace 36 and transfers it to the caterpillar 44 for discharging. The drive of the carrier transfer arms 41 and 42 for supply and discharge, the supply track 43 in the heating furnace 31, and the discharge track 44 in the annealing furnace 36 are controlled by the transfer controller 2. Further, a heating furnace 31, a slow cooling furnace 36, upper and lower heaters 33, 34, a final heating heater 32,
The heating of the slow cooling start heaters 35 is controlled by a temperature control device (not shown) so that the heaters 35 all have a preset temperature.

FIG. 9 shows a timing chart when the optical element is continuously molded by the above-mentioned molding apparatus.
First, the caterpillar 4 exposed from the tip of the heating furnace 31
The carrier 51 holding the optical material 61 is placed in the installation hole 43a of No. 3, and is intermittently transported in the direction of arrow A. When the optical material 61 reaches the outlet 31b of the heating furnace 31, the optical material 61 is saturated at a temperature 20 ° C. to 60 ° C. lower than the moldable temperature. Next, the carrier 51 is transferred to the supply carrier transfer arm 41 and transferred to the final heating heater 32 located in the direction perpendicular to the transfer direction and finally heated to a moldable temperature. Then, after the preset holding time of the final heater has elapsed, the carrier 51 holding the heat-softened optical material 61 is transferred to the molding position 3 by the supply carrier transfer arm 41. Here, a press start command signal is output from the transfer control device 2 to the mold drive control device 1. As a result, the vertical movement motor 21 is driven so as to raise the holding shaft 17 while controlling the pressure in the cylinder 18 to an appropriate value, and the optical material 61 is pressed by the upper mold 11 and the lower mold 12 to be molded.
After that, the mold drive control device 1 outputs a transfer arm exchange command signal to the transfer control device 2. As a result, the supply carrier transfer arm 41 moves backward and returns to the initial position, and the discharge carrier transfer arm 42 moves to the press position 3. Immediately after the supply carrier transport arm 41 returns to the initial position, the caterpillar 43 is intermittently fed, and the molding cycle of the next optical element is started. After a preset press holding time has elapsed, the lower mold 12 returns to the initial position before the start of molding together with the holding shaft 17. As the holding shaft 17 descends, the carrier 51 on which the optical element 62 is placed is transferred to the ejection carrier transport arm 42. Then, it passes through the inside of the slow cooling start heater 35, is conveyed onto the end of the conveying section of the discharge caterpillar 44, and is transferred onto the discharge caterpillar 44. After that, the discharging carrier carrying arm 42 returns to the initial position, and the caterpillar 44 is intermittently fed in the direction of arrow C. The optical element 62 is conveyed in the slow cooling furnace 36 by the intermittent movement of the discharging caterpillar 44 and further cooled, and is taken out from the discharging caterpillar 44 together with the carrier 51 at the tip of the slow cooling furnace 36.

[0007]

By the way, it is important for the quality of the optical element that the optical material to be molded has a predetermined set temperature and the upper mold 11 and the lower mold 12 to be molded also have the predetermined set temperature. Since it has an influence, it is a necessary condition that the heating and the optical material 61 and the upper mold 11 and the lower mold 12 to be press-molded have a predetermined temperature immediately before starting the press-molding.

However, the optical material 6 which is heated to a high temperature
If the temperature of No. 1 is directly and accurately measured and the molding process is started, the apparatus itself becomes expensive. Therefore, in the above-mentioned apparatus, the heating furnace 31 and the final heating heater 3 kept at a constant temperature are used.
Optical material 6 by passing through 2 in a certain time
It is estimated that the temperature of No. 1 has been raised to a constant value, and control is performed so as to start press molding.

As shown in FIG. 9, the starting point of the molding cycle in such molding starts from the one-pitch feed of the supply caterpillar 43, and the one-pitch feed of the supply caterpillar 43 is the origin of the previous supply carrier transfer arm 41. It starts immediately after the completion of position return. Therefore, for example, the time of each molding cycle fluctuates due to fluctuations in sliding resistance and fluctuations in the operating time of actuators such as vertical movement motors due to fluctuations in the drive source. This makes the optical material 6
The time of staying in the heating furnace 31 differs for each one, not only the temperature of the optical material 61 at the time of starting the molding process is different, but also the cycle time for starting the molding process varies as shown in FIG. The temperatures of the upper mold 11 and the lower mold 12 that exchange heat with the optical material during molding are not constant at the start of each molding process. From the above, there is a problem that the quality of the continuously molded optical element varies.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a molding apparatus capable of stabilizing the quality of an optical element even when the optical element is continuously molded.

[0011]

A device for molding an optical element according to the present invention comprises a heating means for heating an optical material passing through the transportation path, which has a transportation path for transporting the optical material, and a heating means for passing the heating material. A mold for pressurizing the formed optical material to form an optical element, a transfer device for transferring the optical material into the heating means and for transferring the optical material from the heating means to the mold, and at least a drive of the mold and a transfer by the transfer device. Is provided with a control means for controlling so as to interlock at a predetermined timing. In this molding apparatus, the control means has a timer circuit for generating a pulse for the control at a constant timing and a control circuit for controlling the driving of the mold and the transportation of the transportation apparatus by the output of the pulse of the timer circuit. Can be configured.

FIG. 1 shows the basic structure of the present invention, which comprises a control means 70, a mold drive control circuit 73 and a transfer control circuit 74. The mold drive control circuit 73 is a mold drive device 75.
The transfer control circuit 74 controls the transfer device 76. Here, the die driving device 75 presses an optical material into an optical element, and the vertical movement motor 21 corresponds to it in FIG. The carrier device 76 uses an optical material for the upper mold 1.
The material is conveyed to a mold including the lower mold 1 and the lower mold 12 (see FIG. 8), and the optical material is heated by the ambient temperature during the conveyance. This transport device is shown in FIG.
In the above, the feeding caterpillar 43 that moves in the heating furnace 31 corresponds.

The control means 70 includes a mold drive control circuit 73 and a transfer control circuit 74 so that the transfer of the optical material in the heating furnace by the transfer device and the driving of the mold for press molding are performed at a predetermined timing. Control. The control means 70 includes a timer circuit 71 that generates a control pulse at a constant timing, and a control circuit 72 that performs the above-described control based on the pulse output from the timer circuit 71.

FIG. 2 shows a timing chart of continuous molding with the above-mentioned structure. The timer circuit 71 generates a pulse for starting the molding cycle, a pulse generated after a predetermined timing after the output of this pulse, and a pulse for holding the optical material in the heating furnace, and a predetermined timing after this pulse. And the pulse for pressing the optical material is output to the control circuit 72. In FIG. 2, first, the molding cycle is started by the timer circuit 71, and the optical material 6
When the charging of No. 1 into the heating furnace 31 is started, the time until the start of the next molding cycle is set, and thereafter, the start of the molding cycle is sequentially activated by the timer circuit 71, and the heating furnace 31 of the optical material 61 is started. Is started. In one molding cycle, after the optical material 61 is carried into the final heating heater 32, the final heating holding time and the press holding time are strictly controlled by the timer circuit 71, and the optical element is press-molded.

[0015]

FIG. 3 shows a block diagram of a control mechanism in an embodiment of the present invention. In this embodiment, heater temperature control circuit 81, optical material supply control circuit 82, mold drive control circuit 7
3 and the optical element discharge control circuit 84 control each molding process, and all of these circuits are controlled by the control circuit 72 of the control means 70. The mechanical structure controlled by this control mechanism is the same as in FIGS. 7 and 8, and hereinafter, referring to FIGS.
The configuration will be described.

The heater temperature control circuit 81 includes a heating furnace 31,
The final heating heater 32, the gradual cooling start heater 35, the gradual cooling furnace 36, the upper die heater 33 and the lower die heater 34 are controlled so as to reach a predetermined set temperature, and the optical material 61 passing through these members is A predetermined temperature is reached depending on the heating time. In this case, the upper mold 11 and the lower mold 1
2 is controlled so that the temperature changed by the press molding is restored. However, when the response time is less than the molding interval of the optical element, the variation of the molding interval causes the upper mold 11 and the lower mold to start molding. There are 12 variations in temperature, and control is also performed for this. Optical material supply control circuit 82
Controls the supply caterpillar 43 and the supply carrier transfer arm 41 of the heating furnace 31. Further, the optical element discharge control circuit 84 includes the carrier carrier arm 42 for discharge and the annealing furnace 3.
6 to control the discharging caterpillar 44. These control circuits 82 and 84 have respective members at predetermined timings,
It is controlled to drive at a predetermined speed. The mold drive control circuit 73 controls the driving of the mold including the upper mold 11 and the lower mold 12.

FIG. 4 shows a timing chart of continuous molding according to this embodiment. First, with the start of the entire molding device,
The timer of the timer circuit 71 is set, and the start pulse of the molding cycle is generated. By the output of this start-up pulse, the supply caterpillar 43 advances by one pitch and the optical material 61 is sent out together with the carrier 51 for one pitch. Next, the carrier 51 is transferred to the supply carrier transfer arm 41, carried into the final heating heater 32, and the timer is set, and the holding time of the carrier 51 in the final heating heater 32 is managed. After the set time has elapsed, the carrier 51 is conveyed to the molding position 3 and the holding shaft 1
The optical material 61 is press-molded by ascending 7 and a timer is set, and the contact time between the optical material 61 and the upper mold 11 and the lower mold 12 is set. Further, at this time, the supply carrier transfer arm 41 returns to the initial position and ends a series of supply operations. Then, the standby state of the molding cycle by the start pulse of the next stage of the molding cycle is entered. That is,
The next molding pulse is started by the start pulse of the next stage.

When the supply carrier transfer arm 41 returns to the initial position, the discharge carrier transfer arm 42 moves to the molding position 3, and the carrier discharge operation is started. That is, the holding shaft 17 is lowered by the press time end signal pulse from the timer circuit 71. Then, as the holding shaft 17 descends, the carrier 51 on which the optical element 62 is mounted is transferred to the discharging carrier transfer arm 42,
After passing through the slow cooling start heater 35, the discharge caterpillar 4
It is replaced on 4. Further, the discharging carrier transfer arm 42 returns to the initial position. In addition, the discharging caterpillar 44 is fed forward by one pitch, and the discharging cycle ends.

According to this embodiment, since the molding cycle interval is controlled by the timer circuit to be a constant time, the residence time of the optical material in the heating furnace can be made constant. Then, the final heating time is similarly controlled to a constant time. Therefore, as shown in FIG. 5, the temperature variation of the optical material at the start of pressing is small, and the variation of the press interval of the optical material by the mold is also small. Therefore,
Since it is possible to suppress variations in mold temperature at the start of pressing, variations in quality are reduced even if optical elements are continuously press-molded.

FIG. 6 shows another example of a timing chart for performing continuous molding. Also in this case, the supply and molding of the optical material is performed by the timer circuit 7 as in the above-described embodiment.
1 is controlled by the start-up pulse of the molding cycle, and the final heating time and the press holding time are controlled so that there is no variation between the continuously molded optical elements. In this example, in addition to the above-described embodiment, the holding shaft 1 after the optical element is molded
The carrier carrier arm for discharge 42, which has been transferred with the carrier 51 as it descends 7, passes through the inside of the slow cooling start heater 35 to replace the carrier 51 on the discharge track 44, and at the same time, the carrier carrier arm for discharge. 42
Returns to the initial position.

In this example, after the optical element has been carried out immediately after the start-up, the timer circuit 71 outputs a start-up pulse for the ejection caterpillar 44 after the expected variation time of the actuator operation. As a result, it is possible to confirm the return of the discharging carrier transport arm 42 to the initial position. The start-up pulse of the discharging caterpillar 44 has the same interval as the start-up pulse of the molding cycle, and the output of the start-up pulse of the discharging caterpillar 44 sends the same track by one pitch. The optical element molded by this is moved one pitch at a time in the slow cooling furnace 36 at the same intervals as the cycle time of molding, and there is no variation in the residence time of the optical element in the slow cooling furnace. Therefore, in this example, since the slow cooling time of the optical element is the same in all molding cycles, it is possible to mold the optical element with less variation in quality.

[0022]

As described above, according to the present invention, the conveyance of the optical material inside the heating means and the press molding of the mold are controlled at a predetermined timing, so that the temperature fluctuation of the optical material and the temperature fluctuation of the mold are reduced. In this way, it is possible to continuously form optical elements with little variation in quality.

[Brief description of drawings]

FIG. 1 is a block diagram of a basic configuration of the present invention.

FIG. 2 is a timing chart of molding with a basic configuration.

FIG. 3 is a block diagram of an embodiment of the present invention.

FIG. 4 is a timing chart of molding according to an example.

FIG. 5 is a temperature characteristic diagram of a mold temperature and an optical material.

FIG. 6 is a timing chart of another molding according to the embodiment.

FIG. 7 is a cross-sectional view of a conventional molding device.

FIG. 8 is a partial plan view of a conventional molding device.

FIG. 9 is a timing chart of molding by a conventional device.

FIG. 10 is a temperature characteristic diagram of a mold temperature and an optical material in a conventional apparatus.

[Explanation of symbols]

 11 Upper mold 12 Lower mold 31 Heating furnace

Claims (2)

[Claims] 1. A heating means for heating an optical material passing through the transportation path, the heating means having a transportation path for transporting the optical material, and a mold for pressurizing the optical material passing through the heating means to form an optical element. A transport device that transports the optical material into the heating means and transports the heating material to the mold, and a control means that controls at least the driving of the mold and the transport by the transport device to interlock at a predetermined timing. A molding device for an optical element characterized in that 2. The control means has a timer circuit for generating a pulse for the control at a constant timing, and a control circuit for controlling the driving of the mold and the transportation of the transportation device by the output of the pulse of the timer circuit. The apparatus for molding an optical element according to claim 1, wherein