JP2015040147A - Method and apparatus for manufacturing optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for surely releasing an optical element material from a die and manufacturing an optical element with high accuracy.SOLUTION: A method for manufacturing an optical element comprises: the first cooling step (a) of cooling a molded optical element material 100 in a state pressurized by a first molding die (an upper die 11) and a second molding die (a lower die 12); a first release step (b) of releasing only a part 100b-1 including a periphery out of the contact surfaces 100a and 100b of the optical element material 100 cooled in the first cooling step from at least one of the first molding die 11 and the second molding die 12; the second cooling step (c, d) of cooling the optical element material 100 having a released part in a state pressurized by the first molding die 11 and the second molding die 12; and the second release step (e) of releasing from the first molding die 11 and the second molding die 12 the optical element material 100 cooled in the second cooling step.

Description

  The present invention relates to an optical element manufacturing method and manufacturing apparatus for manufacturing an optical element.

  2. Description of the Related Art Conventionally, a method for manufacturing an optical element is known in which an optical element is manufactured by press molding with a molding die in a state where the optical element material is heated and softened, and then cooling. In such a method for manufacturing an optical element, after the optical element material is cooled, the optical element material may not be separated from the mold, and cracking may occur.

Therefore, a technique is known in which a release film and a release agent for improving the slipperiness and release properties between the optical element material and the mold are attached to the mold (see, for example, Patent Document 1).
In addition, there is also known a technique for easily forming a gap between the optical element material and the molding die by providing a deformed portion such as a depression that is used to release the mold in the optical element material (see, for example, Patent Document 2). ).

Further, a technique is known in which pressurization of the optical element material and release of the optical element material from at least one of the pair of molds are repeated twice or more (for example, see Patent Document 3).
In addition, there is also known a method for calculating a stress due to shrinkage in a close contact state between the optical element material and the mold by simulation.

JP 2011-162371 A Japanese Patent No. 2914508 JP-A-9-286623

  By the way, in the contact surface with a pair of molds in the optical element material, when there is a maximum thickness portion thicker than the peripheral edge of the contact surface, for example, the optical element has a biconvex shape or a single convex shape. Consider the case of the shape.

In this case, it is considered that the cause when the optical element material cannot be released from the mold is that there is a difference in shrinkage between the thick part and the thin part in the cooling process.
That is, the shrinkage amount of the thick portion is larger than the shrinkage amount of the thin portion, but the shrinkage of the thin portion can actually be shrunk in a state where the optical element material and the mold are in close contact with each other. The thin part is strongly pressed against the mold by the contraction force of the thick part, and it becomes difficult to release as the cooling proceeds. Since the optical element material is first released from the periphery and air enters the gap, the release of the optical element material becomes difficult, particularly when the peripheral edge is thin.

However, in the method using the release film and the release agent as described above, the release film and the release agent are not only essential, but the release is still difficult even if the release film or the release agent is used. There is also.
In addition, the above-described method of providing a deformed portion in the optical element material is based on the start of mold release and ensures a smooth mold release thereafter, and is not a fundamental solution.

  Furthermore, in the above-described method of repeating pressurization and mold release twice or more, the surface shape accuracy of the optical element deteriorates due to the contact surface being displaced when the optical element material comes into contact with the mold again. To do.

  An object of the present invention is to provide an optical element manufacturing method and apparatus capable of reliably releasing an optical element material and manufacturing an optical element with high accuracy.

  The method of manufacturing an optical element of the present invention includes a heating step of heating and softening an optical element material, and heating and softening the optical element material by a first mold and a second mold that are arranged to face each other. A molding step in which the first and second molding dies are pressed to form a shape having a maximum thickness portion thicker than a peripheral edge of the contact surface at the contact surface of the optical element material; A first cooling step of cooling the molded optical element material in a state of being pressurized by the first molding die and the second molding die, and the optical cooled in the first cooling step. A first releasing step of releasing only a part of the contact surface of the element material including the peripheral edge from at least one of the first mold and the second mold; and The released optical element material is converted into the first component. A second cooling step of cooling in a state of being pressurized by the mold and the second molding die, and the optical element material cooled in the second cooling step, the first molding die and the second molding A second release step of releasing from the mold.

  The optical element manufacturing apparatus of the present invention pressurizes the heating element that heats and softens the optical element material and the optical element material with a first mold and a second mold that are arranged to face each other. A molding part that molds the optical element material contact surface with the first molding die and the second molding die into a shape having a maximum thickness portion thicker than a peripheral edge of the contact surface; and the optical A cooling part that cools the element material in a state of being pressurized by the first mold and the second mold, and a part of the contact surface of the optical element material that is cooled in the cooling part, including a peripheral edge Only the first control for releasing from at least one of the first mold and the second mold, and the optical element material partially released from the first mold and Cooling in a state of being pressurized by the second mold Comprising a second control, and a control unit for performing the optical element material is cooled from the first mold and the second mold and the third control to release, the in the cooling unit.

  According to the present invention, the optical element material can be reliably released and the optical element can be manufactured with high accuracy.

It is sectional drawing which shows the manufacturing apparatus of the optical element which concerns on one embodiment of this invention. It is sectional drawing which shows the optical element material, the upper mold | type, and the lower mold | type for demonstrating the manufacturing method of the optical element which concerns on one embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the optical element which concerns on a comparative example. It is sectional drawing which shows the optical element material in the 1st modification of one embodiment of this invention, an upper mold | type, and a lower mold | type. It is sectional drawing which shows the optical element material in the 2nd modification of one embodiment of this invention, an upper mold | type, and a lower mold | type. It is sectional drawing which shows the optical element material in the 3rd modification of one embodiment of this invention, an upper mold | type, and a lower mold | type. It is sectional drawing which shows the optical element material, the upper mold | type, and the lower mold | type in the 4th modification of one embodiment of this invention. It is sectional drawing which shows the optical element material in the 5th modification of one embodiment of this invention, an upper mold | type, and a lower mold | type. It is sectional drawing which shows the manufacturing apparatus of the optical element which concerns on other embodiment of this invention.

Hereinafter, an optical element manufacturing method and manufacturing apparatus according to embodiments will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an optical element manufacturing apparatus 1 according to an embodiment of the present invention.

The optical element manufacturing apparatus 1 shown in FIG. 1 includes a first stage 2, a second stage 3, a third stage 4, a molding chamber 5, and a control unit 6.
The first stage 2, the second stage 3, and the third stage 4 are arranged in this order in the molding chamber 5 in the transfer direction of the mold set 10 that houses the optical element material 100. The optical element material 100 is, for example, glass, and the manufactured optical element is, for example, a glass lens.

  The mold set 10 includes an upper mold 11 and a lower mold 12 that are disposed to face each other, and a cylindrical body mold 13 that is disposed around the upper mold 11 and the lower mold 12, and the mold set 10 includes an optical element material 100. If it can accommodate and can perform each process mentioned later, it will not restrict | limit.

  The upper mold 11 is an example of a first mold, and the lower mold 12 is an example of a second mold. As shown in FIG. 2, the upper mold 11 has a concave molding surface 11a formed on the bottom surface, for example. As shown in FIG. 2, the lower mold 12 also has, for example, a concave molding surface 12a formed on the upper surface.

  The first stage 2, the second stage 3, and the third stage 4 are composed of upper heater blocks 2a, 3a, 4a, upper heat insulating blocks 2b, 3b, 4b, press shafts 2c, 3c, 4c, and cylinders. 2d, 3d, 4d, lower heater blocks 2e, 3e, 4e, and lower heat insulation blocks 2f, 3f, 4f.

  For example, cartridge heaters are inserted into the upper heater blocks 2a, 3a, 4a. The upper heater blocks 2a, 3a, 4a are in contact with the upper surface of the mold set 10 and heat the mold set 10 by heat conduction.

The upper heat insulating blocks 2b, 3b, 4b are disposed on the upper heater blocks 2a, 3a, 4a.
The press shafts 2c, 3c, 4c are connected to the center of the upper surface of the upper heat insulating blocks 2b, 3b, 4b at the lower ends.

  The cylinders 2d, 3d, and 4d are connected to the press shafts 2c, 3c, and 4c, and move the upper heater blocks 2a, 3a, and 4a, the upper heat insulating blocks 2b, 3b, and 4b, and the press shafts 2c, 3c, and 4c up and down.

  The lower heater blocks 2e, 3e, 4e are arranged to face the upper heater blocks 2a, 3a, 4a, and the mold set 10 is placed on the upper surface. For example, cartridge heaters are inserted in the lower heater blocks 2e, 3e, 4e. The lower heater blocks 2e, 3e, and 4e are in contact with the bottom surface of the mold set 10 and heat the mold set 10 by heat conduction.

The lower heat insulating blocks 2f, 3f, 4f are located below the lower heater blocks 2e, 3e, 4e and are fixed to the bottom surface in the molding chamber 5.
The upper heater block 2a and the lower heater block 2e in the first stage 2 function as an example of a heating unit that heats and softens the optical element material 100.

Further, the cylinder 2d in the first stage 2 functions as an example of a molding unit that molds the optical element material 100 by pressurizing it.
The upper heater blocks 3a and 4a and the lower heater blocks 3e and 4e in the second stage 3 and the third stage 4 are cooled so that the optical element material 100 is cooled in a state of being pressurized by the upper mold 11 and the lower mold 12. It functions as an example of a unit.

  The molding chamber 5 includes a mold inlet shutter 5a, a mold outlet shutter 5b, a mold inlet base 5c, and a mold outlet base 5d.

The mold inlet shutter 5a is opened when the mold set 10 is loaded into the molding chamber 5 from the mold loading table 5c.
The mold discharge shutter 5b is opened when the mold set 10 is discharged from the molding chamber 5 to the mold discharge table 5d.

  As will be described in detail later, the control unit 6 controls the first stage 2, the second stage 3, and the third stage 4 in each step such as heating, pressurization, cooling, and mold release.

Hereinafter, a method for manufacturing the optical element according to the present embodiment will be described.
FIG. 2 is a cross-sectional view showing the optical element material 100, the upper mold 11, and the lower mold 12 for explaining the method of manufacturing an optical element according to the present embodiment.

As shown in FIG. 1, the mold set 10 is loaded into the molding chamber 5 from the mold loading table 5c by a transfer robot (not shown) with the mold loading shutter 5a opened.
The mold set 10 put into the molding chamber 5 is placed on the lower heater block 2 e of the first stage 2. The mold set 10 comes into contact with the bottom surface of the upper heater block 2a when the cylinder 2d lowers the upper heater block 2a.

  The optical element material 100 accommodated in the mold set 10 is heated and softened by heat conduction from the upper heater block 2a and the lower heater block 2e through the upper mold 11 and the lower mold 12 (heating process).

  The heat-softened optical element material 100 is pressed and molded by the cylinder 2d through the upper mold 11 and the lower mold 12 (molding process). As shown in FIG. 2A, the shape of the optical element material 100 molded in this molding step is the maximum thickness that is thicker than the peripheral edge at the contact surfaces 100a, 100b with the upper mold 11 and the lower mold 12. It is the shape which has the part 100c.

  In the present embodiment, the shape in which the optical element material 100 is molded is a biconvex shape. However, in the present embodiment, the diameter is 10 mm, the thickness of the maximum thickness portion 100 c is 2.3 mm, and the thickness of the outermost peripheral portion (the same as the thickness of the peripheral edges of the contact surfaces 100 a and 100 b). A glass lens which is a 9 mm optical element is manufactured.

  In the molding step, flat portions 100e and 100f are formed in at least a part (flange portion) of the contact surface 100a and 100b of the optical element material 100 outside the effective diameter 100d of the optical element. The effective diameter 100d of the optical element is a portion (optical functional surface) that exhibits optical characteristics, and is, for example, a part of a convex portion.

When the optical element material 100 is glass, the heating temperature of the optical element material 100 in the molding step is, for example, a temperature near the softening point, for example, 570 ° C. to 580 ° C. The viscosity of the optical element material 100 at this time is, for example, 10 ^7.8 [dPa · s].

Thereafter, the mold set 10 is transferred from the first stage 2 to the second stage 3 by a transfer robot (not shown). Note that the transfer interval of each stage is, for example, 40 seconds.
The optical element material 100 molded in the molding process is cooled in a state where the upper mold 11 and the lower mold 12 are pressurized (arrows D1 and D2) as shown in FIG. 2A (first cooling process). ). In the first cooling process, the optical element material 100 is pressed with a pressure lower than that in the molding process, for example.

  Next, the mold set 10 is transferred from the second stage 3 to the third stage 4 by a transfer robot (not shown). During this transfer, the mold set 10 is released from the pressurized state in the second stage 3. That is, the pressure for pressurizing the optical element material 100 by the upper mold 11 and the lower mold 12 is reduced. Therefore, as shown in FIG. 2B, the optical element material 100 is repelled and deformed (arrows D11, D12, D13, D14), and the interval between the upper mold 11 and the lower mold 12 is increased.

  Thereby, the cooling may have progressed, and of the contact surfaces 100a and 100b of the optical element material 100 cooled in the first cooling step, the periphery (preferably the entire periphery of the periphery) of the contact surface 100b with the lower mold 12 ) Including only a part 100b-1 is released from the lower mold 12 (an example of at least one of the upper mold 11 and the lower mold 12) (first mold release step). The part 100b-1 including the peripheral edge is, for example, a part outside the effective diameter 100d.

  The control of the control unit 6 in the first mold release step is performed by removing only a part 100b-1 including the periphery of the contact surfaces 100a and 100b of the optical element material 100 from the lower mold 12 (the upper mold 11 and the lower mold 12). It is an example of the 1st control made to release from at least one of them.

The repulsive force of the optical element material 100 is a force that causes the optical element material 100 to deform in the direction opposite to the pressing direction when the pressure applied to the optical element material 100 is released. In order to increase the repulsive force, the pressure for pressurizing the optical element material 100 in the second stage 3 may be increased before the transfer to the third stage 4. Note that the viscosity is 10 ^10.5 [dPa · s] by applying a pressure of about 32 [N / mm ² ] if the optical element material 100 has a biconvex shape with a diameter of about 12.5 mm. Sufficient repulsive force can be obtained when it is cooled down.

In the first release step, it was found that the optical element material 100 should be released at a temperature not lower than the glass transition point and a viscosity not lower than 10 ^9.6 [dPa · s]. An example of the viscosity of the optical element material 100 at this time is 10 ^10.5 [dPa · s], and an example of the temperature is 520 ° C. to 540 ° C.

  If the temperature of the optical element material 100 in the first mold release step is too high, shape transfer from the upper mold 11 and the lower mold 12 is not sufficiently advanced, so that the surface accuracy is deteriorated, or the optical element material 100 Insufficient repulsive force causes a problem in that the mold release at the periphery does not proceed, or the contraction force at the maximum thickness portion 100c is only slightly accumulated, and the mold release effect is small.

  Further, if the temperature of the optical element material 100 in the first mold release step is too low, shape transfer proceeds, and the first mold release step is omitted and the entire mold is released (second mold release step described later). The state of mold release is close to the case of performing from the beginning. Therefore, the effect that the mold can be reliably removed by performing both the first mold release process and the second mold release process cannot be sufficiently obtained.

  In the second stage 3, the inclination between the pressurizing direction of the upper mold 11 and the pressurizing direction of the lower mold 12, that is, the inclination of the central axis of the cylinder 2d with respect to the direction orthogonal to the upper surface of the lower heater block 2e is 0, for example. It may be set in the range of 7 minutes to 1.5 minutes. This is because the releasing action at the peripheral edges of the contact surfaces 100a and 100b due to the repulsive force and the contracting force can be enhanced according to the shape of the optical element material 100.

  The optical element material 100 from which the part 100b-1 has been released is pressed through the upper mold 11 and the lower mold 12 by the cylinder 4d of the third stage 4 (arrows D1 and D1 shown in FIG. 2C). It is cooled in D2) (second cooling step). Thereby, as shown in FIG.2 (d), the optical element material 100 shrink | contracts by cooling (arrow D21-D28).

The control of the control unit 6 in the second cooling step is an example of second control for cooling the optical element material 100 from which the part 100b-1 has been released while being pressed by the upper mold 11 and the lower mold 12. is there.
As described above, the part 100b-1 including the periphery is first released from the mold, so that the close contact state between the upper mold 11 and the lower mold 12 is once released. Since the periphery is in contact with the upper mold 11 and the lower mold 12, the timing at which the periphery is pressed by the upper mold 11 and the lower mold 12 can be greatly delayed.

  As a result, the pressures D1 and D2 received by the optical element material 100 from the upper mold 11 and the lower mold 12 are the pressures D1-1 and D2-1 at the maximum thickness portion 100c and the pressures D1-2, D1-3 and D2 at the periphery. The difference between −2 and D2−3 is reduced. Here, the part 100b-1 that has been released from the optical element material 100 may be brought into close contact with the lower mold 12 again, or may not be attached as long as a desired optical surface is obtained.

  In the present embodiment, since the first mold release process is performed when the mold set 10 is transferred from the second stage 3 to the adjacent third stage 4, the first mold release process is completed after the first mold release process is completed. It is possible to prevent a temperature difference from occurring in the optical element material 100 before the start of the second cooling step. Since this temperature difference can cause discontinuous surfaces on the contact surfaces 100a and 100b of the optical element material 100, it is desirable that the temperature difference be 10 ° C. or less, for example. Further, the change in the pressing direction of the optical element material 100 between the second stage 3 and the third stage 4 (change in the pressing direction of each of the upper mold 11 and the lower mold 12) is within 0.5 minutes. Is desirable.

  In the second cooling step (third stage 4), the optical element material 100 is pressurized with a pressure lower than that in the first cooling step (second stage 3). Although it is an example to the last, the pressure in a 2nd cooling process is 100 [kgf]-200 [kgf], for example, and the pressure in a 1st cooling process is 450 [kgf] or less, for example.

  In at least one of the second stage 3 and the third stage 4, a temperature difference within, for example, 20 ° C. may be generated between the upper heater blocks 3a and 4a and the lower heater blocks 3e and 4e. Thereby, the curvature accompanying the shrinkage | contraction of the optical element material 100 can be controlled, and the shape of the contact surfaces 100a and 100b which release according to the shape of the optical element material 100 can be controlled.

  Next, the mold set 10 is discharged out of the molding chamber 5 from the third stage 4 by a transfer robot (not shown). During this discharge, the mold set 10 is released from the pressurized state in the third stage 4.

  As a result, as shown in FIG. 2E, the optical element material 100 cooled in the second cooling step is released from the entire upper mold 11 and lower mold 12 (second release process). Note that the second release step may be performed only by cooling in the pressurized state of the second stage 3. Further, the second mold release step may be performed in the fourth and subsequent stages that are cooled to a temperature lower than that of the third stage 4 or outside the molding chamber 5.

  The control of the control unit 6 in the second mold release step is to release the optical element material 100 cooled in the upper heater block 4a and the lower heater block 4e of the third stage 4 from the upper mold 11 and the lower mold 12. 3 is an example of control 3.

An example of the viscosity of the optical element material 100 in the second release step is 10 ^14.5 [dPa · s], and it has been found that the temperature may be, for example, a temperature equal to or higher than the strain point. The viscosity in the second release step is preferably between 10 ¹³ [dPa · s] and 10 ^14.6 [dPa · s] corresponding to the strain point temperature. However, since the ease of destruction depends on the shape of the optical element material 100, the viscosity may be 10 ^14.6 [dPa · s] or more as long as the optical element material 100 does not break. . An example of the temperature of the optical element material 100 is 480 ° C to 500 ° C.

  The optical element material 100 is taken out from the mold set 10 discharged out of the molding chamber 5. This extracted optical element material 100 is an optical element. In the present embodiment, there was no crack even when 200 optical elements were manufactured continuously, and good surface accuracy was obtained.

FIG. 3 is a cross-sectional view for explaining a method for manufacturing an optical element according to a comparative example.
In this comparative example, the entire mold release is performed at one time without dividing the mold release process into the first mold release process and the second mold release process as in the present embodiment.

  Therefore, the optical element material 100 that is pressure-molded (arrows D1 and D2) as shown in FIG. 3A and contracts by cooling (arrows D21 to D28) as shown in FIG. The amount of shrinkage increases.

  Thereby, as shown in FIG. 3C, the pressure (D1-1, D2-1) that should be applied at the center is reduced (arrows D1-11, D2-11), and the pressure (D1) that should be applied at the periphery. -2, D1-3, D2-2, D2-3) becomes larger (arrows D1-12, D1-13, D2-12, D2-13). Therefore, it is usually difficult to release the peripheral edge that causes the release, and the optical element material 100 can be broken.

  In the present embodiment described above, the optical element manufacturing method includes a heating step, a molding step, a first cooling step, a first mold release step, a second cooling step, and a second release step. And a mold process. In the heating step, the optical element material 100 is softened by heating. In the molding process, the heat-softened optical element material 100 is pressurized by an upper mold (an example of a first mold) 11 and a lower mold (an example of a second mold) 12 that are arranged to face each other. The contact surfaces 100a and 100b of the optical element material 100 with the upper mold 11 and the lower mold 12 are molded into a shape having a maximum thickness portion 100c that is thicker than the peripheral edges of the contact surfaces 100a and 100b. In the first cooling step, the molded optical element material 100 is cooled while being pressed by the upper mold 11 and the lower mold 12. In the first mold release step, only a part 100b-1 including the periphery of the contact surfaces 100a and 100b of the optical element material 100 cooled in the first cooling step is removed from the lower die 12 (the upper die 11 and the lower die). Release from at least one of 12). In the second cooling step, the optical element material 100 from which the part 100b-1 has been released is cooled in a state of being pressurized by the upper mold 11 and the lower mold 12. In the second release step, the optical element material 100 cooled in the second cooling step is released from the upper mold 11 and the lower mold 12.

  For this reason, in the contact surfaces 100a and 100b, when the maximum thickness portion 100c having a thickness larger than that of the periphery exists, even if the contraction amount in the maximum thickness portion 100c is larger than the contraction amount of the periphery, the periphery is first The state of close contact with the upper mold 11 and the lower mold 12 at the periphery is released by releasing the mold. As a result, the thick portion contracts sufficiently, and then the peripheral edge comes into contact with the upper mold 11 and the lower mold 12, so that the timing at which the peripheral edge is pressed by the upper mold 11 and the lower mold 12 can be greatly delayed. Thereby, it can suppress that a periphery is strongly pressed by the upper mold | type 11 and the lower mold | type 12 by the difference in contraction force. Therefore, mold release from the periphery becomes easy. In addition, since only part 100b-1 is released in the first release step, the surface shape accuracy of the optical element is deteriorated due to the contact surfaces 100a and 100b being displaced during re-pressurization in the second cooling step. Can be suppressed.

  Therefore, according to the present embodiment, the optical element material 100 can be reliably released and the optical element can be manufactured with high accuracy.

In the present embodiment, in the first mold release step, the optical element material 100 includes a part including the peripheral edge at a temperature equal to or higher than the glass transition point and a viscosity equal to or higher than 10 ^9.6 [dPa · s]. Release of only 100b-1 is performed. Therefore, the mold release is performed in a state where the pressing of the peripheral edges of the contact surfaces 100a and 100b is not progressing and the viscosity remains in the optical element material 100, whereby the repulsive force and contraction force of the optical element material 100 While the maximum thickness part 100c rises, the peripheral edge shrinks in the radial direction, and the mold release of only a part 100b-1 including the peripheral edge becomes easy. Therefore, the optical element material 100 can be released more reliably.

  In the present embodiment, when the optical element material 100 is transferred from the second stage 3 to the third stage 4 in the first mold release step, the optical element material 100 is used by the upper mold 11 and the lower mold 12. The pressure of pressurizing is reduced and the optical element material 100 is repelled to widen the distance between the upper mold 11 and the lower mold 12, so that only part of the part 100 b-1 including the peripheral edge is released. Thereby, since the mold release is performed without directly moving the upper mold 11 and the lower mold 12, the mold can be released according to the state of the optical element material 100. Therefore, the optical element material 100 can be released more reliably.

  Moreover, in this Embodiment, the shape by which the optical element material 100 is shape | molded in a shaping | molding process is a biconvex shape. Therefore, since the thickness of the maximum thickness portion 100c is larger than the thickness of the peripheral edges of the contact surfaces 100a and 100b, it becomes difficult to release the mold. However, the first and second release processes are difficult. The optical element material 100 can be reliably released.

  In the present embodiment, in the molding step, flat portions 100e and 100f are formed in at least a part of a region outside the effective diameter 100d of the optical element in the contact surface 100 of the optical element material 100. Therefore, even in the optical element material 100 having the flat portions 100e and 100f in which the radial contraction is a sliding action on the molding surfaces 11a and 12a of the upper mold 11 and the lower mold 12, and the mold release is difficult, the first separation is performed. The optical element material 100 can be reliably released by the mold process and the second mold release process.

4 to 8 are cross-sectional views showing the optical element material, the upper mold, and the lower mold in the first to fifth modifications of the present embodiment.
The shape of the optical element material molded in the molding step can be any shape other than the biconvex shape of the optical element material 100 having the flange portion formed with the flat portions 100e and 100f shown in FIG. .

  An example of the shape is a biconvex shape having a maximum thickness portion 200c at the center as in the optical element material 200 shown in FIG. 4 (first modification), but flat portions or flanges on the contact surfaces 200a and 200b. The shape which does not have a part is mentioned. The optical element material 200 is molded by the upper mold 21 and the lower mold 22 on which concave molding surfaces 21a and 22a are formed.

  Further, like the optical element material 300 shown in FIG. 5 (second modified example), the optical element material 300 has a flange portion having a maximum thickness portion 300c at the center and flat portions 300e and 300f formed on the contact surfaces 300a and 300b. Examples include a convex meniscus shape. The optical element material 300 is molded by an upper mold 31 on which a convex molding surface 31a is formed and a lower mold 32 on which a concave molding surface 32a is formed.

  Further, like the optical element material 400 shown in FIG. 6 (third modified example), a convex meniscus shape having a maximum thickness portion 400c at the center and no flat portions or flange portions on the contact surfaces 400a and 400b. Can be mentioned. The optical element material 400 is molded by an upper mold 41 having a convex molding surface 41a and a lower mold 42 having a concave molding surface 42a.

  Further, like the optical element material 500 shown in FIG. 7 (fourth modified example), the maximum thickness portion 500c is provided in a portion other than the periphery and other than the center, and the flat portions 500e and 500f are provided on the contact surfaces 500a and 500b. The concave meniscus shape which has the formed flange part is mentioned. This optical element material 500 is molded by an upper mold 51 having a convex molding surface 51a and a lower mold 52 having a concave molding surface 52a.

  Further, like the optical element material 600 shown in FIG. 8 (fifth modified example), the thickest portion 600c is provided at a portion other than the periphery and other than the center, and the flat portions 600e and 600f are formed on the contact surfaces 600a and 600b. The biconcave shape which has the formed flange part is mentioned. The optical element material 600 is molded by an upper mold 61 and a lower mold 62 on which convex molding surfaces 61a and 62a are formed.

In addition, the lower mold | type 62 shown in FIG. 6 is divided | segmented into the cylindrical part of the outer peripheral side, and the columnar part of the inner peripheral side, for example.
Of course, the shape of the optical element material to be molded is not limited to the examples of FIGS. 2 and 4 to 8, and these are merely examples.

FIG. 9 is a cross-sectional view showing an optical element manufacturing apparatus 1-1 according to another embodiment of the present invention.
In the optical element manufacturing apparatus 1-1 of the present embodiment, the stage is only the single stage 7. As with the first stage 2, the second stage 3, and the third stage 4, the single stage 7 includes an upper heater block 7a, an upper heat insulating block 7b, a press shaft 7c, a cylinder 7d, and a lower stage. It has a heater block 7e and a lower heat insulation block 7f.

In the present embodiment, the upper mold 11-1 is fixed to the bottom surface of the upper heater block 7a. The lower mold 12-1 is fixed to the upper surface of the lower heater block 7e.
The molding chamber 8 has a material loading / unloading shutter 8a for loading and discharging the optical element material 100.

  The control unit 9 controls each process such as heating, pressurization, cooling, and mold release described above for only the single stage 7. Since the stage is only the single stage 7, the control unit 9 can perform control while detecting the state of the optical element material 100 using a temperature measurement unit (not shown). Of course, the control unit 9 may divide each process by time.

  About each process (heating process, molding process, first cooling process, first mold releasing process, second cooling process, and second mold releasing process) of the manufacturing method of the optical element in the present embodiment, Since the optical element material 100 (the mold set 10) is not transferred and the respective steps are performed in the single stage 7, it is the same as that of the above-described embodiment, and thus the description thereof is omitted.

  However, in the first mold release step, the optical element material 100 is reduced by reducing the pressure applied to the optical element material 100 by the upper mold 11-1 and the lower mold 12-1, as in the above-described embodiment. May be deformed by repelling, but by moving at least one of the upper mold 11-1 and the lower mold 12-1 (in this embodiment, the upper mold 11-1) away from the other, You may do the mold.

  In the other embodiments described above, the same effects as those of the one embodiment described above can be obtained. Furthermore, since the heating process to the second mold release process can be performed in the single stage 7, a change (inclination) in the pressurization direction due to pressurization in different stages before and after the first mold release process. Can be prevented. In addition, the time required for each process can be controlled in consideration of temperature, not uniform time control. Therefore, the optical element material 100 can be released more reliably.

DESCRIPTION OF SYMBOLS 1 Optical element manufacturing apparatus 2 1st stage 3 2nd stage 4 3rd stage 2a, 3a, 4a Upper heater block 2b, 3b, 4b Upper heat insulation block 2c, 3c, 4c Press shaft 2d, 3d, 4d Cylinder 2e, 3e, 4e Lower heater block 2f, 3f, 4f Lower heat insulating block 5 Molding chamber 5a Type inlet shutter 5b Type outlet shutter 5c Type inlet 5d Type outlet 6 Controller 7 Single stage 7a Upper heater block 7b Heat insulation block 7c Press shaft 7d Cylinder 7e Lower heater block 7f Lower heat insulation block 8 Molding chamber 8a Material input / discharge port shutter 9 Control unit 10 Mold set 11 Upper mold 11a Molded surface 12 Lower mold 12a Molded surface 13 Body mold 100 Optical element material 100a , 100b Contact surface 100c Maximum thickness portion 100d Effective diameter 100e, 1 00f Flat part

Claims (7)

A heating step for heating and softening the optical element material;
The optical element material of the first mold and the second mold by pressing the heat-softened optical element material with a first mold and a second mold that are arranged to face each other. A molding step of molding into a shape having a maximum thickness portion that is thicker than the peripheral edge of the contact surface at the contact surface of the material;
A first cooling step of cooling the molded optical element material in a state of being pressurized by the first mold and the second mold;
Of the contact surface of the optical element material cooled in the first cooling step, only a part including the peripheral edge is released from at least one of the first mold and the second mold. A first mold release step;
A second cooling step of cooling the part of the optical element material released from the part in a state of being pressurized by the first mold and the second mold;
A second release step of releasing the optical element material cooled in the second cooling step from the first mold and the second mold;
The manufacturing method of the optical element characterized by the above-mentioned. In the first mold releasing step, only a part of the optical element material is released at a temperature equal to or higher than a glass transition point and a viscosity equal to or higher than 10 ^9.6 [dPa · s]. The method for producing an optical element according to claim 1.   In the first mold release step, only the part of the mold is released by moving at least one of the first mold and the second mold away from the other. The manufacturing method of the optical element of Claim 1 or 2.   In the first release step, the pressure for pressurizing the optical element material by the first mold and the second mold is decreased, and the optical element material is repelled to repel the first mold and the first mold. 3. The method of manufacturing an optical element according to claim 1, wherein only a part of the mold is released by widening an interval between the two molds.   5. The method of manufacturing an optical element according to claim 1, wherein the shape of the optical element material formed in the forming step is a biconvex shape. 6.   The flat part is formed in at least one part of the area | region outside the effective diameter of the said optical element among the said contact surfaces of the said optical element material in the said shaping | molding process. 2. A method for producing an optical element according to item 1. A heating section for heating and softening the optical element material;
Contact of the optical element material with the first mold and the second mold by pressurizing the optical element material with a first mold and a second mold which are arranged opposite to each other. A molded part that is molded into a shape having a maximum thickness part that is thicker than the peripheral edge of the contact surface on the surface;
A cooling unit that cools the optical element material in a state of being pressurized by the first mold and the second mold;
First control for releasing only a part including the periphery of the contact surface of the optical element material cooled in the cooling unit from at least one of the first molding die and the second molding die. A second control for cooling the optical element material partly released from the first mold and the second mold in a pressurized state, and the cooling by the cooling unit. A control unit that performs a third control for releasing the optical element material from the first mold and the second mold;
An optical element manufacturing apparatus comprising: