JP2003226528A - Apparatus and method of forming lens element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming apparatus in which elevating speed of a lower metallic mold is controlled while adding forming load by a cylinder and a material is inserted into the upper and lower metal mold to start the forming without giving impact load to prevent causing the change of the shape and the damage of the metallic mold. <P>SOLUTION: The forming apparatus is provided with the upper metallic mold 1 fixed to an upper heater block 4 in which a heater 6a is incorporated and the lower metallic mold 2 fixed to a lower heater block 5 in which a heater 6b is incorporated and which moves up and down by the cylinder 8 and a taper plate 9 acting by a pulse motor 10 for controlling the position and the elevating speed of the lower metallic mold 2 to heat and form a glass material in a tightly closed mold inside and is constituted so as to once stop the lower metallic mold before the mold is closed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens element molding apparatus and a molding method for molding a glass element, which is a glass molded product, by a press or the like using a mold.

[0002]

2. Description of the Related Art A conventional lens element molding apparatus shown in FIG. 9 has an upper heater block 4 in which an upper die 1 is mounted and a heater 6a is arranged, and a lower die 2 in which a sleeve 3 is inserted, and a heater 6b. , A lower heater block 5 in which is arranged, a lower shaft 7 connected to a cylinder at a lower portion outside the head, which is a closed space for molding, and a pipe 26 for introducing nitrogen.
It consisted of

In the lens element molding apparatus constructed as described above, conventionally, in the molding process of a lens element made of glass, the temperature in the vicinity of a pair of upper and lower molds is detected and the mold is made of a glass material. A glass material having a glass transition temperature or higher and a softening point temperature or lower is heated to a temperature at which a glass material can be molded, and a molding pressure is generated by using a cylinder and an electropneumatic proportional valve to perform molding.

[0004]

In this molding apparatus, it is difficult to control the speed in the low speed region because the load is applied by the force of the cylinder when the upper die and the lower die sandwich the glass material. there were. Therefore, there is a problem that an impact load is applied to the mold, the mold shape is deformed, the optical characteristics of the lens element become unstable, and the mold is broken.

The present invention solves the above-mentioned problems of the prior art by controlling the ascending speed while applying the molding load of the lower mold by a cylinder, and sandwiching the material between the upper and lower molds without impact load for molding. An object of the present invention is to provide a molding device and a molding method for a lens element that starts and does not cause shape change and damage of a mold.

[0006]

In order to achieve the above object, the present invention has the following constitution.

According to a first aspect of the present invention, a pair of molds having curved surfaces for press-molding a lens element made of glass, and at least one mold of the pair of molds are pressed to a predetermined pressure. The driving means for advancing and retreating with, and the mold moved by the driving means are temporarily stopped at a predetermined position before being brought into contact with the glass material forming the lens element, and then brought into contact with the glass material. This is a molding device of a lens element having a stopper function for pressure molding, which has the effect of reducing deformation and damage of the mold due to impact at the start of molding.

According to a second aspect of the present invention, in the first aspect of the invention, the lens element molding apparatus is provided with a mechanism for driving the die by a cylinder, and a mechanism for applying pressure during molding by the cylinder. This has the effect that the drive source and the molding pressure supply reduction can be integrated.

According to a third aspect of the present invention, in the invention according to the first aspect, there is provided a taper plate disposed between a molding portion having a closed stopper function and a cylinder which is a drive source. The lens element molding apparatus is configured to control the vertical position and speed of the lower mold by moving the taper plate in the left-right direction. This has the effect of reducing the impact at the start of molding.

According to a fourth aspect of the present invention, in the third aspect of the invention, there is provided a lens element molding apparatus in which the drive source of the taper plate is a pulse motor, which makes it possible to inexpensively form a stopper. Have an effect.

According to a fifth aspect of the present invention, in the invention of the first aspect, there is provided a molding device for a lens element having a function of introducing nitrogen into a sealed molding part through a pipe. It has the effect that the position of blowing out nitrogen can be freely determined without oxidizing.

The invention according to claim 6 of the present invention is, in the invention according to claim 1, a rotary table for supplying a glass material from the outside to a sealed molding portion and taking out the molded lens element to the outside, This is a lens element molding device that has a lever that vacuum-adsorbs glass materials and glass elements with a tip nozzle that can be flexibly tilted between the rotary table and the lower die and conveys them. It has the effect of being able to.

According to a seventh aspect of the present invention, in the second aspect of the invention, an electropneumatic proportional valve for switching the pressure during vertical movement of the cylinder and during molding is connected to the lower die, and the molding is performed. A molding device for a lens element having a sensor arranged outside the head for detecting a displacement, which has an effect of being able to freely switch while observing the pressure and the displacement during molding.

According to an eighth aspect of the present invention, in the first aspect of the invention, a plate and a holder for fixing the upper die to the upper heater block by using elastic force,
The lower die is a molding device for a lens element that has a plate and a holder that can be moved within a certain area without being fixed, and that does not come off from the lower heater block. Therefore, molding can be performed depending on the precision of the die. Has the effect of.

According to a ninth aspect of the present invention, in the first aspect of the invention, a vacuum hole for fixing the upper die and the lower die by vacuum suction under an environment of a molding temperature of about 600 ° C. It is a molding device of a lens element having an upper heater block and a lower heater block having the above, and has an effect that alignment accuracy is high and optical characteristics can be stabilized.

According to a tenth aspect of the present invention, in the invention according to the first aspect, the collar whose height is adjusted in advance in order to forcibly complete the molding in the vicinity of the glass material is a lower mold. The lens element molding apparatus has the function of stabilizing the thickness of the lens element made of glass.

According to an eleventh aspect of the present invention, at least one of a pair of molds having a curved surface for press-molding a lens element made of glass is moved at a first pressure, The mold moved by the first pressure was stopped at a predetermined position before the pair of molds sandwiched the glass material forming the lens element, and then moved by the first pressure. A molding method of a lens element, in which the mold is moved at a lower speed than the above to clamp the glass material, and the glass material is pressure-molded by a second pressure larger than the first pressure. It has the effect of reducing the deformation and damage of the mold due to the impact at the start.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The invention described in claims 1 to 11 of the present invention will be described below with reference to embodiments.

FIG. 1 is a perspective view of a main part of a molding apparatus for a lens element according to an embodiment of the present invention, FIG. 2 is a characteristic diagram of temperature, displacement and pressure in the molding process, and FIG. 3 is a mold configuration of the apparatus. 4A, 4B, and 4C are main-part cross-sectional views showing the pre-aligned state of the mold of the apparatus, and FIG. 5 is a cross-section of the main part of the mold of the apparatus. Figure, Figure 6 (a), (b),
(C) is a sectional view of an essential part showing an inserted state of the upper mold of the apparatus,
FIG. 7 is a cross-sectional view of a main part of a mold part of the device, and FIG. 8 is a cross-sectional view of a main part of a lever part of the device.

In FIG. 1, 1 is an upper mold having a curved surface for press-molding a lens element made of glass which is an object to be molded, 2 is a lower mold corresponding to the upper mold 1, and 3 is a lower mold. A sleeve 4 inserted in the lower mold 2 is an upper heater block having a heater 6a for heating the upper mold 1, and a lower heater block 5 is a heater 6b having a heater 6b for heating the lower mold 2, 7, the lower heater block 5 is fixed to the upper part,
Lower shaft connected to the cylinder 8 at the lower part, 1
0 is a pulse motor of a drive source attached to a fixed system (not shown), 11 is a ball screw that rotates in conjunction with the pulse motor 10, 9 is attached to the nut portion of the ball screw 11, and can be easily replaced, A taper plate serving as a stopper that moves in the direction, a sensor 12 for detecting a distance from the plate 13 attached to the lower shaft 7, and a rotating body 14 attached to the lower shaft 7 at a portion in contact with the taper plate 9. , 15 has a drive source (not shown) in the lower part of the head, which is a closed space for molding in order to supply the glass material in the sealed molding head and to take out the completed lens element, A swingable lever, 16 is a rotary table which has a pocket 17 and which is turned upside down with a back plate constituting a closed space for molding as a fulcrum. A.

In FIG. 2, the horizontal axis represents time and the vertical axis represents changes in temperature, pressure and displacement. T1 at temperature
Is a room temperature near 30 ° C., T2 is a supply / extraction temperature near the glass transition point and below the glass transition point, and T3 is a molding temperature. In the pressure, P1 is the first pressure for raising the lower mold 2 to sandwich the glass material 24, and P2 is the molding temperature T.
The second pressure P3 at which molding is performed at 3 is a pressure smaller than P2 which is switched after confirmation of completion of molding at the molding temperature T3. In the displacement, S1 is a preset value, which is about half the total deformation amount, and S2 is the displacement when the deformation speed becomes zero.

In FIG. 3, 18 is an upper holder for fixing the upper mold 1 by fixing the outer periphery of the upper mold 1 and tightening the plate 20 with a screw 21, and 19 is the upper direction of the lower mold 2. It is a lower holder for doing.

First, as shown in FIG. 3, the upper mold 1 and the lower mold 2 and the sleeve 3 are mounted by mounting the upper mold 1 and the lower mold 2 on the upper heater block 4 at room temperature T1. And the lower heater block 5 at predetermined positions.
At room temperature T1 and at a molding temperature T3 above the glass transition point, the centers of the upper mold 1 and the lower mold 2 change due to the difference in thermal strain of the constituent parts. Therefore, in order to make the upper mold 1 depend on the processing accuracy of the mold itself at the molding temperature T3 without guaranteeing the mounting accuracy at room temperature, the upper mold 1 is provided with the screw 2
The plate 20 is fixed by the elastic force of the plate 20 generated by pressing it with the upper holder 18, the sleeve 3 is inserted into the lower mold 2, and the lower holder 19 is attached with the screw 2. It is designed so that it can be freely moved in a certain area in the lower holder 19 without being fixed by receiving. Therefore, the centers of the upper mold 1 and the lower mold 2 depend on the accuracy of the inner circumference of the sleeve 3 when the lower mold 2 rises and the sleeve 3 arranged in the lower mold 2 enters the upper mold 1. It will be.

When mounting the mold, the center of the upper mold 1 and the lower mold 2 should be centered under the environment of the molding temperature T3, that is, in the state where the thermal distortion of the metal parts constituting the molding machine occurs. You may use the method for the purpose of matching. Figure 4
4 (a) is a view before the upper die 1 is attached, and FIG.
FIG. 4B is a diagram when the lower mold 2 is lifted and the upper mold 1 is mounted by vacuum suction, and FIG. 4C shows the adjustment sleeve 22 after the upper mold 1 is mounted on the production sleeve 3. FIG. Reference numeral 22 is an adjustment sleeve, and 23 is a vacuum hole for vacuum-sucking the upper mold 1 and the lower mold 2 provided in the heater block.

As shown in FIG. 4A, first, the lower mold 2
An adjusting sleeve 22 having an inner diameter smaller than that of the sleeve 3 used for production is inserted into the shaft portion of the above, and the upper mold 1 is further inserted into the sleeve 22. In this state, the lower mold 2 is fixed by vacuum suction and raised. At this time, the molding temperature T3 is 6
Since the temperature is near 00 ° C., the mold exists in a closed space having a low oxygen concentration in order to prevent the metal from being oxidized, so that it is difficult for a person to fix it. Therefore, the flat portion of the upper mold 1 is sucked and fixed to the upper heater block 4 by vacuum suction (FIG. 4).
(B)). Then, the temperature is lowered to room temperature T1, and the upper die 1
Lowers the lower mold 2 while being fixed to the upper heater block 4 by vacuum suction. Then, the adjustment sleeve 22 is replaced with the production sleeve 3 and molding is performed (FIG. 4C).

In FIG. 5, reference numeral 26 is a pipe for introducing nitrogen into the head, which is a closed space for molding.
After the upper mold 1 and the lower mold 2 are attached, the inside of the molding apparatus is sealed and nitrogen is introduced for a certain period of time to reduce the oxygen concentration. At this time, the nitrogen outlet can be provided with the pipe 26 on the side surface or the bottom surface in the head to reduce the change in thermal strain during molding.

In this state, the upper mold 1 and the lower mold 2 attached to the upper heater block 4 and the lower heater block 5 are attached.
Raise the temperature of. Raise the temperature to supply / extract temperature T2,
Hold the temperature. Pocket 1 of the rotary table 16
The glass material 24 is supplied to the inside of the molding device 7 outside the molding head, and the rotary table 16 is rotated to move the pocket 17 in which the glass material 24 is arranged into the head. The glass material 24 is vacuum-sucked by the nozzle 28 (see FIG. 8) at the tip of the lever 15, and the lever 15 turns to supply the lower mold 2. After that, the temperature rise is started toward the molding temperature T3 that is equal to or higher than the glass transition point and equal to or lower than the softening point temperature, and the lower mold 2 is raised with a low load P1.

In FIG. 6, reference numeral 24 is a glass material supplied to the lower mold 2 before molding.

As shown in FIG. 6, the lower mold 2 is attached to the lower shaft 7 by a taper plate 9 standing by at the lower part of the head between the lower heater block 5 and the cylinder 8 for driving and pressing. Contact the rotating body 14,
Immediately before the sleeve 3 is inserted into the upper mold 1, the rise is stopped (Fig. 6 (a)). During this period, the upper mold 1 and the lower mold 2 are still heated.

After the upper heater block 4 and the lower heater block 5 have reached the molding temperature T3 for a certain period of time, the lower die 2
Begins to rise. At this time, when the sleeve 3 inserted in the lower mold 2 comes into contact with the edge portion of the upper mold 1 (see FIG. 6).
The taper plate 9 is moved in the left-right direction so that the impact load of (b) and the impact load when the glass material 24 arranged in the lower mold 2 and the upper mold 1 come into contact are not moved, and the lower shaft 7 is moved. While controlling the speed of the lower mold 2, the press pressure is applied by the cylinder 8 to raise the lower mold 2.

By changing the contact angle with the rotating body 14 by exchanging the taper plates 9 having different taper angles, it is possible to easily change the speed movement amount of the lower mold 2.

Thereafter, the glass material 24 is sandwiched and the molding is started (FIG. 6 (c)).

Since the moving speed of the taper plate 9 in the left-right direction is sufficiently high, the speed of the rotating body 14 moving upward through the taper plate 9 is also sufficiently higher than the speed at which the glass material 24 is crushed. The rising speed of the lower mold 1 after contacting the mold 1 and the lower mold 2 with the glass material 24 is the deformation speed of the glass material 24.

The glass material 2 is pressed by the cylinder 8 under pressure P1.
The deformation of No. 4 and the deformation to the predetermined amount S1 are detected by the sensor 12 arranged at the lower part of the head, and the electropneumatic proportional valve raises the load to the predetermined load P2 to perform molding. At this time, the molding is completed by detecting that the displacement speed becomes 0.

In FIG. 7, 25 is a collar for controlling the height during molding.

As shown in FIG. 7, when the deformation is completed, a method of forcibly pushing the material into a push-cut state by a height-regulated collar 25 arranged on the outer circumference of the sleeve 3 arranged in the lower mold 2 is used. You may use.

After pressing, the heating of the heaters 6a and 6b is stopped, and the temperature is lowered by the cooling effect by blowing nitrogen at room temperature. At this time, if nitrogen is directly blown to the lens element 27, a difference in temperature distribution occurs in the lens element 27 itself, and when the lens element 27 solidifies, anisotropy occurs, so that the entire lens element 27 is subjected to the same temperature condition. For this purpose, nitrogen is blown to the bottom surfaces 4a and 5a of the upper heater block 4 and the lower heater block 5 to cool the upper heater block 4 and the lower heater block 5, the upper mold 1 and the lower mold 2 simultaneously (FIG. 5). While cooling, upper heater block 4
The temperature of the lower heater block 5 is detected, and the pressure of the electropneumatic proportional valve is switched to reduce the load of the cylinder applied to the lens element 27.

After confirming that the lens element 27 and the upper mold 1 and the lower mold 2 are not impacted, the taper plate 9 is moved while controlling the speed so that the lens element 27, the upper mold 1 and the lower mold 2 are not cooled. Lower 2 slowly. After the upper mold 1 and the lower mold 2 are sufficiently separated, the lower mold 2 is lowered by the cylinder. After confirming the downward movement, the taper plate 9 moves to a predetermined position where the upper die 1 and the sleeve 3 are not brought into contact with each other when the lower die 2 is raised in preparation for the next molding.

In FIG. 8, 27 is a lens element after molding, 29 is a pin attached to a lever 15 having a vacuum hole 30 for vacuum suction of the lens element 27, and 31 is a nozzle 28 which is not sucked by vacuum. It is a receiver for keeping the time.

Finally, as shown in FIG. 8, the lever 1 is used to take out the lens element 27, which has been molded, from the lower mold 2.
The lens element 27 is taken out by inserting the nozzle 28 arranged at the tip of No. 5 into the lower mold 2 and sucking it in vacuum. The bottom surface of the nozzle 28 is conical, and the pin 29
The abutting part has a spherical shape, the nozzle 28 can follow the inclination of the lens element 27, and the vacuum leak from the upper surface of the lens element 27 can be prevented.
The lens element 27 attracted to the tip of the nozzle 28 turns the lever 15 to move the pocket 17 of the rotary table 16.
Placed inside. After that, the lens element 27 is taken out of the molding head by the rotation of the rotary table 16.

[0041]

As described above, according to the present invention, it is possible to obtain a lens element having stable optical characteristics without deformation and damage of the mold.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main configuration of a lens element molding apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the relationship between temperature, displacement and pressure in the molding process in the same device

FIG. 3 is a cross-sectional view of a main part of a mold forming part of the apparatus.

FIG. 4 (a), (b), (c) is a cross-sectional view of an essential part showing a pre-aligned state of a mold forming part of the same apparatus.

FIG. 5 is a sectional view of a main part of a mold part of the same device.

6 (a), (b) and (c) are cross-sectional views of essential parts showing an inserted state of an upper die of the same apparatus.

FIG. 7 is a cross-sectional view of a main part of a mold part of the device.

FIG. 8 is a sectional view of a main part of a lever part of the device.

FIG. 9 is a sectional view of a main part of a conventional lens element molding apparatus.

[Explanation of symbols]

1 Upper mold 2 Lower mold 3 sleeves 4 Upper heater block 5 Lower heater block 6a, 6b heater 7 Lower shaft 8 cylinders 9 Taper plate 10 pulse motor 11 ball screw 12 sensors 13 plates 14 rotating body 15 lever 16 rotating table 17 pockets 18 Upper holder 19 Lower holder 20 plates 21 screws 22 Adjustment sleeve 23 vacuum holes 24 glass materials 25 colors 26 pipes 27 lens elements 28 nozzles 29 pin 30 vacuum holes 31 Receiving

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyoshi Minato             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (11)

[Claims] 1. A pair of molds having curved surfaces for press-molding a lens element made of glass, drive means for moving at least one mold of the pair of molds at a predetermined pressure, and the drive. And a stopper function of temporarily pressing the mold moved by the means at a predetermined position before contacting with the glass material forming the lens element, and then contacting with the glass material to perform pressure molding. Lens element molding equipment. 2. A lens element molding apparatus according to claim 1, further comprising a mechanism for applying a pressure during molding by a cylinder as a driving means of the mold. 3. The stopper function has a taper plate arranged between a closed molding part and a cylinder which is a drive source, and the taper plate is moved in the left-right direction to move the taper plate in the vertical direction of the lower die. The lens element molding apparatus according to claim 1, wherein the apparatus is configured to be capable of controlling the position and the speed. 4. The lens element molding apparatus according to claim 3, wherein the driving source of the taper plate is a pulse motor. 5. The lens element molding apparatus according to claim 1, which has a function of introducing nitrogen into the sealed molding portion through a pipe. 6. A rotary table for supplying a glass material from the outside to a sealed molding portion and taking out the molded lens element to the outside, and a glass material and the glass element are tilted flexibly between the rotary table and the lower mold. The lens element molding apparatus according to claim 1, further comprising a lever for vacuum suction and conveyance by a possible tip nozzle. 7. An electropneumatic proportional valve for switching the pressure during vertical movement of the cylinder and during molding, and a sensor for detecting a displacement connected to the lower mold and arranged outside the molding part. 2. The lens element molding apparatus according to item 2. 8. A plate and a holder for fixing the upper mold to the upper heater block by using elastic force, and a lower mold that can be moved within a certain area without being fixed and cannot be separated from the lower heater block. The lens element molding apparatus according to claim 1, further comprising a plate and a holder. 9. The upper heater block and the lower heater block having a vacuum hole for fixing the upper mold and the lower mold by vacuum adsorption under an environment of a molding temperature near 600 ° C. Lens element molding equipment. 10. The lens element molding apparatus according to claim 1, wherein the lower mold has a collar whose height is adjusted in advance to forcibly complete the molding in the vicinity of the glass material. 11. A glass which comprises at least one of a pair of molds having a curved surface for press-molding a lens element, the mold is moved by a first pressure, and the pair of molds constitutes the lens element. The mold moved at the first pressure is stopped at a predetermined position before the material is clamped, and then the mold is moved at a lower speed than when the mold is moved at the first pressure. A method of molding a lens element, comprising sandwiching a material, and press-molding the glass material with a second pressure that is higher than the first pressure.