JPH0640731A - Method for conveying optical element member by attraction - Google Patents

Abstract

(57) [Summary] [Purpose] The molding die and the optical element are not regenerated when the molded optical element is taken out from the molding die without causing harmful defects in the molded optical element which is the final product. Provided is a method for sucking and transporting an optical element member, by which an optical element having no defects can be continuously manufactured by smoothly taking out the optical element from a molding die without causing adhesion. In a process of sucking and transporting or placing an optical element member, a predetermined gap is provided between the suction surface of the suction member and the optical element member when the optical element member is sucked by the suction member. In the opened state, the optical element member is adsorbed to the adsorption member, or when the optical element member adsorbed by the adsorption member is placed on the lower molding surface of the molding die or on the pedestal, With a predetermined gap between the lower die molding surface or the receiving surface of the pedestal and the optical element member, the adsorption to the optical element member is released,
The optical element is dropped at the interval and placed on the molding surface of the lower mold or the receiving surface of the pedestal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, when forming a high-precision optical element such as an aspherical lens by press molding, the material of the optical element and the molded optical element are formed before and after the press molding. The present invention relates to a method for attracting and transporting an optical element member that is attracted by a suction action and transported.

[0002]

2. Description of the Related Art In recent years, a method of directly press-molding a heat-softened glass material in a molding die has attracted attention, instead of a method of processing an optical element by grinding and polishing. Usually, for this type of molding, a molding die member consisting of an upper die and a lower die that slides in the body die is used to press the glass material in a softened state to correspond to the forming surface of the die member. The optical functional surface is formed on the glass material, then cooled, the mold member is disassembled, or, depending on the case, one of the upper and lower molds is separated from the formed optical element, and then the optical element is formed. Is used.

As a method of taking out of this kind, Japanese Patent Application Laid-Open No. 63-63
Japanese Patent Laid-Open No. 297229 proposes a vacuum chuck type press-molded product releasing apparatus equipped with a mold cooling mechanism. This is because when the upper die is lifted after the press is completed and the press-molded product is taken out from the die, the vacuum chuck equipped with a die cooling mechanism enters the upper portion of the lower die to cool the lower die and remove the bellows. Through this, the suction plate attached to the holder of the vacuum chuck is brought into contact with the molded product, and the molded product is taken out by vacuum suction.

In Japanese Patent Laid-Open No. 64-42332, as a similar method of carrying by vacuum suction, a lens molding material and a lens by suction holding means elastically pressed downward and supported so as to be vertically movable. A method for sucking and conveying a molded article is disclosed.

[0005]

However, since the molding of the optical element by press molding is performed at a high temperature of several hundreds of degrees, the temperature of the optical element member that is sucked and conveyed is inevitably high, and the suction member used An elastic body such as rubber cannot be used for the cradle, and a heat-resistant material such as metal must be used. Therefore, in the conventional example,
When a molded optical element or an optical element member such as an optical element material before molding is first contacted with the suction member at the time of suction, a pressing force is exerted at the time of contact, and a small amount of force between the optical element member and the suction member. However, there is a problem in that the optical element, which is the final product, has a defect because the optical element, which is the final product, is rubbed against the suction member due to such a positional displacement or vibration generated from the device side, which causes an optically harmful scratch. Also, when the optical element member is placed on the molding surface of the lower die or on the pedestal, when the optical element member is brought into contact with the receiving surface of the lower die or the pedestal, pressure is applied and the same problem occurs. Was. Further, when the molded optical element is taken out of the molding die, even if the molded optical element is released from the molding die, the shapes of the molding die and the optical element are almost the same, and the contact surfaces of both are optical. Since it has a very smooth surface so that it has a function, the mold and the optical element are likely to come into close contact again with a slight pressure, making it impossible to remove the mold by vacuum suction. There was a problem.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention is to prevent the optical element which is a molded final product from causing harmful defects.
Moreover, when taking out the molded optical element from the molding die, the optical element can be smoothly taken out from the molding die without causing re-adhesion between the molding die and the optical element. Another object of the present invention is to provide a method for adsorbing and conveying an optical element member that can be manufactured according to the above method.

[0007]

Therefore, in the present invention,
For example, when suctioning an optical element member, vacuum suction is performed with a gap of 2 mm or less provided between the suction section and the optical element, so that even if the suction section is made of a hard material such as metal, By not causing harmful scratches on the optical element member, and when adsorbing the optical element having the surface shape of the molding die transferred from the mirror-polished molding die, a gap of 1 mm or less By performing vacuum suction in the state where the vacuum mold is installed, re-adhesion does not occur, and when mounting on the lower mold of the optical element member after suction conveyance or on the receiving stand, the lower mold and the receiving mold By releasing the suction from the state where a gap of 2 mm or less is opened between the table and the sucked optical element member, and by releasing the suction with some free fall, it is possible to stabilize the optical element without defects. , So that it can be manufactured continuously.

[0008]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 schematically shows an automatic press molding apparatus of the present invention. A molding section A for heating an optical element material in an inert gas atmosphere such as a nitrogen gas atmosphere to perform press molding; and a molding section. A supply unit B for supplying the optical element material to A, and a supply section B for taking out the formed optical element from the forming section A into the atmosphere; The robot unit C carries out the produced optical elements from the supply unit B and sequentially stocks them.

The molding section A includes a molding chamber 1 having an airtight structure, a molding die 2 installed therein, and a molding die 2.
Pressing mechanism 6 for opening and closing and pressurizing, and forming die 2
It is composed of a turning hand mechanism 12 for inserting the optical element material into and removing the molded optical element. In the molding die 2, the upper die 4 and the lower die 5 are inserted into the body die 3 having the opening 3b for inserting and withdrawing the optical element member, from above and below the through hole opened substantially at the center thereof. Then, the bottom plate 3a for restricting the position of the lower die 5 is screwed to the bottom of the assembly.

The press mechanism 6 includes a press shaft 7 having a hook 8 for pulling up the upper mold 4 of the mold 2, and a press shaft 7.
And a press cylinder 9 for raising and lowering the pressure and a press cylinder shaft 10 fastened to the press shaft 7. Further, since the press shaft 7 maintains airtightness in the molding chamber 1, As shown in the drawing, the O-ring 11 is sealed between the molding chamber 1 and the upper die 4 for inserting the optical element material and taking out the molded optical element according to the movement of the press cylinder 9. In addition, the upper mold 4 for press molding can be pressed.

The swivel hand mechanism 12 has a swivel shaft 13 which extends vertically through the bottom of the molding chamber 1,
A swivel arm 15 mounted horizontally on the swivel shaft 13,
It is composed of a suction hand 14 attached to the tip of the swivel arm 15 in a suspended state. Swivel axis 1
Similarly to the press shaft 7, 3 is attached to the molding chamber 1 via an O-ring (not shown) for keeping airtightness, and similarly, a rotary swivel mechanism (not shown) and a vertical movement mechanism. As shown in the figure, the structure allows swiveling and vertical movement, and further, the suction pipe 16 connected to the suction hole (not shown) for suction provided in the shaft of the swivel shaft 13.
, Which is connected to the suction air intake hole 14a of the suction hand 14, inserts the optical element material supplied by the supply section B into the lower mold 5 of the molding die 2, and further lowers the molded optical element. It can be taken out from the mold 5 and placed on the supply section B. Further, a gate valve 17 is provided at the connection portion of the molding chamber 1 with the supply portion B, so that the airtightness inside the molding chamber can be maintained at the time of connection with and separation from the supply portion B.

In the supply section B, the pedestal 22 is mounted on the slide base 21, the cylinder shaft 23a of the cylinder 23 is fastened to the pedestal 22, and the pedestal 22 is moved in accordance with the movement of the cylinder 23. It can be moved horizontally on top of. Furthermore,
The cylinder 31 is fixed to the upper part of the gantry 22,
The substitution chamber 27 is provided so as to be vertically movable via a cylinder shaft 31a of the cylinder 31.

Further, a shifter 24 is arranged so as to pass through the central portion of the substitution chamber 27, and a pedestal 25 of an optical element material and a pedestal 26 of the molded optical element are mounted on the shifter 24. . The cylinder 30 is fixed to the lower part of the pedestal 22, and the cylinder shaft 30a of the cylinder 30 is fastened to the bottom of the shifter 24.
O-rings 28.29 are provided at the rubbed portions of the upper open surface of the displacement chamber 27 and the shifter 24, respectively, so that the airtightness in the molding chamber can be maintained when the gate valve 17 is connected. ing.

The robot section C moves the pallet 32 on which the optical element material and the molded optical element are stocked, the suction finger 33 to which the suction exhaust pipe 34 is connected, and the vertical movement of the suction finger 33. Cylinders 35 and 36, and an XY stage 37 for horizontally moving the suction finger 33 to an arbitrary point on the pallet 32.

2 and 3, in the above system, a ball-shaped blank 40 or a ball-shaped blank 40 whose outer peripheral surface, which is an optical element material, is smoothly processed by polishing, flame treatment or acid treatment. The state of the gap when the optical element 41 is adsorbed in each step or released from the adsorption is shown.

FIG. 2A shows the suction finger 3
3 shows the state of the gap La between the blank 40 and the contact portion of the suction finger 33 when the blank 40 is sucked from the pallet 32. FIG. 2B shows the blank 40 sucked from the pallet 32. When the optical element material is placed on the pedestal 25, the blank 40 and the pedestal 25
The state of the gap Lb with the contact portion is shown.

Similarly, FIG. 2C shows the state when the suction hand 14 sucks the blank 40 from the receiving table 25, and FIG. 2D shows the state where the blank 40 is separated from the suction hand 14. 3A is a state when the optical element 41 is sucked from the lower mold 5 by the suction hand 14, and FIG. 3B is a state when the optical device 41 is sucked out from the lower mold 5. The optical element 41 is separated from the suction hand 14, and the optical element support 2
3 is a state when the optical element 41 is sucked from the receiving table 26 by the suction finger 33, and FIG. 3C is a state when the optical element 4 is moved from the suction finger 33.
1 shows a state in which they are separated from each other and placed on the pallet 32, and the necessary clearance L is set at the time of suction and suction release, respectively.
It is shown that c, Ld, Le, Lf, Lg, and Lh are opened. Further, among the respective gaps, the gaps La, Lb, Lg, and Lh related to the suction finger 33 can be adjusted by restricting the strokes of the cylinders 35 and 36, and the gap Lc related to the suction hand 14, L
As shown in the figure, d, Le, and Lf are stoppers 14b provided on the suction hand 14, the pedestals 25 and 26, and the body mold 3.
It is secured by abutting against a part of.

Further, the suction hand 14 and the suction finger 3
3, and the pedestal 26 has a built-in heater (not shown) for temperature control so that the optical element immediately after molding at high temperature will not be cracked due to a sudden temperature change.
The temperature is controlled, the suction hand 14 is molybdenum, the suction fingers 33 and the pedestal 26 used in the atmosphere are stainless steel, and the temperature is relatively high (200
Similarly, the pallet 32 on which the optical element of up to 350 ° C. is placed and the pedestal 25 exposed to the high temperature atmosphere are made of stainless steel, respectively. Also, the cradle 2
5, 26 and the pallet 32 are provided with breather holes 25a, 26a, 32a for the purpose of stabilizing positive suction by making it easier to apply positive pressure to the non-suction surface of the optical element member during suction.

Next, the step of molding an optical element molded article using the above system will be described more specifically. The optical element molded here has a curvature R of the surface formed by the upper mold used in a camera, a video camera, or the like.
= 16 mm, the surface formed by the lower mold has an approximate curvature of about R = 15 mm, and is an aspherical lens with a diameter of 14 mm. The glass material used here has a temperature of 620.
It is a viscous SK12 having a viscosity of 10 ^9.5 poise at ℃, 10 ¹³ poise at 534 ℃, and 10 ¹⁶ poise at 480 ℃. The molding was performed in a closed furnace in an N ₂ atmosphere in order to prevent the mold from being oxidized.

Before the start of molding, the amount of deviation between the suction center of the suction hand 14 and the suction finger 33 necessary for suction and release of suction and the center of the placement position of the lower die 5, the receiving trays 25, 26 and the pallet 32 is ±. After aligning the axes so that the distance is within 0.1 mm, as shown in FIGS. 2 and 3, Le = 0.3 mm in each gap, and the remaining gaps are all 0.6 ± 0. It was adjusted to be 2 mm. Next, the suction hand 14 was set to 400 ° C., the pedestal 26 was set to 275 ° C., the suction finger 33 was set to 200 ° C., and the inside of the molding chamber 1 was replaced with a nitrogen atmosphere.

After the suction hand 14, the pedestal 26 and the suction fingers 33 have reached a predetermined temperature, molding is started. First, the cylinders 35 and 36 are lifted, and the suction finger 33 is moved right above the first blank 40 on the pallet 32 by the XY stage 37, and the cylinder 3 is moved.
An adsorption source (not shown) connected to the adsorption intake pipe 34 by lowering 5 and 36 to the state shown in FIG.
Was operated to adsorb the blank 40 on the adsorption finger 33.

Next, the cylinders 35 and 36 are raised,
X so that the suction finger 33 is directly above the pedestal 26
After moving the Y stage 37, the cylinder 35 was lowered to the state shown in FIG. 2B, the suction was released, and the blank 40 was allowed to fall freely on the pedestal 25. Next, with the blank 40 placed on the pedestal 25, the cylinder 23 is retracted, the supply part B is moved below the gate valve 17, the cylinder 31 is operated, the replacement chamber 27 is raised, and the replacement chamber 27 After the upper portion and the lower portion of the gate valve 17 are brought into close contact with each other through the O-ring 28, a portion surrounded by the displacement chamber 27 and the gate valve 17 is made into a nitrogen atmosphere by a vacuum exhaust device and a nitrogen supply device (not shown). Replaced.

After that, the gate valve 17 is opened and the cylinder 30 is operated to insert the shifter 24 into the molding chamber 1 and swivel down the swivel shaft 13.
The stopper 14b of the suction hand 14 was pressed against the shoulder portion of the pedestal 25 to bring it into the state shown in FIG. 2C, and at the same time, heating of the mold 3 was started. When the temperature of the molding die reaches 450 ° C., the suction source is operated, the blank 40 is suctioned by the suction hand 14, and the swivel shaft 13 is raised and swung to move the suction hand 14 to the die of the molding die 2. Opening 3b of 3
2), the revolving shaft 13 is lowered again, the stopper 14b of the suction hand is brought into contact with the barrel die, and the state shown in FIG. 2 (d) is reached. Then, the suction is released and the blank 40 is freely dropped onto the lower die. Let

After placing the blank 40 on the lower die 5, the swivel shaft 13 is lifted and swung to return the suction hand 14 to the position shown in FIG. 1, and when the forming die 2 reaches 620 ° C., the press is performed. The cylinder 9 was lowered, pressure was applied so that the blank 40 conformed to the cavity shape formed by the upper mold 4 and the lower mold 5, and cooling of the mold was started 1 minute after pressurization.

On the other hand, the shifter 24 returns the cylinder 30 immediately after the suction hand 14 has sucked the blank 40 from the cradle 25, then closes the gate valve 17, returns the cylinder 31, and further ejects the cylinder 23. , Returned to the initial position shown by the broken line in FIG. 1, and in that state,
As described above, the XY stage 37, the cylinders 35 and 3
The next blank is placed on the pedestal 25 by the 6 and the suction fingers 33, and is again inserted into the molding chamber 1 through the same steps as described above, and the previous blank is molded into an optical element to mold the mold 2. It was kept waiting until it was taken out from.

When the temperature of the molding die 2 is cooled to 450 ° C., the press cylinder 9 rises, and when the upper die 4 is pulled up by the hook 8 of the press cylinder shaft 10, the swivel shaft 13 swivels and the suction hand. 14 was inserted into the opening 3b of the barrel die 3, and the turning shaft 13 was further lowered to bring the state of FIG. 3 (a). The clearance La between the molded optical element 41 and the suction hand at this time is 0.3 mm, which is a dimension for surely sucking the optical element 41 and the suction hand 14 without directly contacting each other, as described above. Is set to.

In the state of FIG. 3 (a), the optical element 41 is sucked by the suction hand 14, and the swivel shaft 13 is raised and swung,
The suction hand 14 was brought onto the pedestal 26, the revolving shaft 13 was lowered to the state of FIG. 3B, the suction was released, and the optical element 41 was allowed to fall freely on the pedestal 26.
At this point, heating of the molding die 2 is started, and when the temperature of the molding die reaches 450 ° C., the blank 40 already in the standby state is placed on the pedestal 25 by the same process as described above. It was placed on the lower mold 5 of 2.

When the blank 40 on the pedestal 25 is sucked by the suction hand 14, the shifter 24 is returned to the initial position shown by the broken line in FIG. 1 in the same manner as described above, and the suction finger 33 moves the XY stage. The horizontal movement of 37 and the lowering of the cylinder 35 bring them to the position shown in FIG. The gap Lg (= 0.6 ± 0.2 m shown in FIG. 3C)
3), the optical element 41 is adsorbed by the adsorption finger 33, moves up the cylinder 35, moves the XY stage, and moves down the cylinder 35.
In the state of (d), the blank is taken out by adsorption release and placed on a predetermined position of the pallet 32 that has been emptied by free fall.

Then, as described above, a new next blank is placed on the pedestal 25, and the mold 2 is already used.
In order to carry out the optical element which is being molded and is being molded, and to supply the blank to be molded next to the molding die 2, the Shitahoo 24 is inserted into the molding chamber, and the above-described steps are repeated to Element materials were sequentially molded, and optical elements having a desired shape were continuously produced.

In this way, using the above system,
We tried molding several thousand shots, but the optical element molded under the conditions with the above-mentioned gap at the time of adsorption and desorption,
There is no occurrence of optically harmful scratches or the like due to suction conveyance by the suction hand 14 or the suction finger 33.
In addition, when taking out from the molding die 2, the suction hand 14
Then, the molded optical element was not pressed, and the phenomenon of being unable to be taken out due to the re-adhesion did not occur at all.

On the contrary, as in the conventional case, the condition that the gap between the respective parts is 0, and the suction hand 14 and the swivel arm 15 are used.
And between the suction finger 33 and the cylinder 35.
A cushioning material in the shape of a spring is provided between the and to soften the shock when contacting, and the optical element member is softly contacted and pressed by the suction hand or the pedestal during suction and release. In the case of the sucked and conveyed optical element, defects such as harmful scratches due to contact were confirmed in more than half of the molded number. Further, when the optical element is taken out from the lower mold 5 of the molding die 2, re-adhesion due to pressing occurs at a rate of 20 to 30 times, and the operation of the apparatus is stopped and a mold releasing treatment is manually performed each time. Things were needed and continuous production was impossible at all.

Further, by changing the set value of each gap,
Using an optical element member of the same system and shape as the above, as a result of performing an experiment to determine the limit value of the gap of each part,
If the gap Le exceeds 0.6 mm, adsorption becomes unstable,
Something that cannot be adsorbed begins to occur, and when it exceeds 1 mm,
Most of the gaps cannot be adsorbed, and when the gaps other than the gap Le exceed 1.2 mm, the adsorption becomes unstable like the gap Le, and when it exceeds 2 mm, the adsorption becomes impossible. However, the occurrence of scratches and the like due to free fall when adsorbing is released does not occur even if it exceeds 3 mm, and when it exceeds 5 mm, about 20% of the optical elements have scratches and scratches that are marginal in terms of optical function. Occurrence of bruising was observed.

Separately from the above embodiment, a spherical lens having a diameter of 11 mm having a curvature of the surface formed by the upper mold R = 17 mm and a curvature of the surface formed by the lower mold R = 8 mm was molded. Then, the state of the gap was verified, but almost the same result as above was obtained, and the stable range of the gap Le was 0.6 m.
m, the stable area of the remaining gap is 1.2 mm, and the gap Le
Was 1 mm, and the remaining gap was 2.1 mm or more, adsorption was impossible, and the occurrence of optically harmful scratches was confirmed at a time of 6 mm or more.

In this embodiment, stainless steel and molybdenum are used as the material of the contact member of the optical element member.
Not limited to this, it is clear that the same result can be obtained by using a heat-resistant ceramic, cermet, or the same cemented carbide as the mold material.

[0035]

As described above, according to the present invention, when the optical element member is conveyed by vacuum suction, the optical element member is sucked and sucked with a certain predetermined gap during suction.
Further, at the time of releasing the suction, by performing the suction release accompanied by free fall from a state having a predetermined gap, without causing an optical harmful defect in the molded optical element,
When the molded optical element is taken out from the molding die, it is possible to smoothly and stably manufacture the optical element without defects without causing a situation in which adsorption and removal cannot be performed due to re-adhesion.

[Brief description of drawings]

FIG. 1 is a schematic front view of an automatic press molding apparatus used in an embodiment of the present invention.

FIG. 2 is a diagram showing a state of suction conveyance of an optical element material used in the present invention.

FIG. 3 is a diagram illustrating a suction conveyance state of an optical element used in the present invention.

[Explanation of reference symbols] A molding unit B supply unit C robot unit 1 molding chamber 2 molding mold 4 upper mold 5 lower mold 6 press mechanism 12 swivel hand mechanism 13 swivel shaft 14 suction hand 17 gate valve 25 cradle 26 cradle 32 pallet 33 suction finger

Claims (8)

[Claims] 1. A step of adsorbing and transporting an optical element member, wherein a predetermined space is provided between the optical element member and an adsorption surface when the optical element member is adsorbed by the adsorption member. Then, the method for adsorbing and transporting an optical element member, characterized in that the optical element member is adsorbed to the adsorption member. 2. In the step of sucking and transporting and mounting the optical element member, when mounting the optical element member sucked by the suction member on the lower molding surface of the molding die or on the pedestal,
With a predetermined gap between the optical element member and the lower die molding surface or the receiving surface of the pedestal, the suction to the optical element member is released, and the optical element is dropped at the gap. A method for sucking and transporting an optical element member, characterized by placing the optical element member on the lower die molding surface or on the receiving surface of a receiving table. 3. The optical element member, wherein the optical element has an optical functional surface molded by a molding die, and at least the surface which becomes the optical functional surface after molding is smoothly treated by polishing, acid treatment, flame treatment or the like. The method for sucking and transporting an optical element member according to claim 1 or 2, which is a material of an optical element that is provided. 4. The optical element member according to claim 1, wherein the suction surface of the suction member is made of a hard material having heat resistance such as cemented carbide, metal, ceramics, and cermet. Adsorption transfer method. 5. The lower die and the receiving surface of the pedestal are made of a hard material having heat resistance such as cemented carbide, metal, ceramics, cermet and the like. Method for sucking and transporting optical element members. 6. The distance is 2 mm or less, preferably,
The range of 0.1-1.2 mm is set, The adsorption | suction conveyance method of the optical element member of Claim 1 or 2 characterized by the above-mentioned. 7. The method for sucking and transporting an optical element member according to claim 1, wherein the step of sucking and transporting is a step of taking out an optical element from a molding die by suction. 8. The distance is preferably 1 mm or less, more preferably 0.
8. The range of 1 to 0.6 mm.
The method for adsorbing and transporting an optical element member according to.