JP2016210650A - Manufacturing method of optical element, molding die, and manufacturing apparatus of optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding die or the like from which an optical element is easily released in manufacturing the optical element having a concave optically functional surface by press molding.SOLUTION: A molding die 11 is used in a method for manufacturing an optical element by press molding. The molding die 11 includes a transfer surface 11a having an inversion region 11b to an optically functional surface that has a convex shape inverting to an optically functional surface of the optical element. A groove 11d serving as a relief part that does not contact an optical element material 100 is located at an outer periphery side of the inversion region 11b to an optically functional surface of the transfer surface 11a and inside a range the optical element material 100 reaches in press molding.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an optical element manufacturing method and manufacturing apparatus for manufacturing an optical element by heating and pressing a thermoplastic optical element material such as glass with a mold.

  In recent years, a method for manufacturing an optical element by so-called press molding is known, in which a thermoplastic optical element material such as glass is heated and pressed by a mold, and the shape of the mold is transferred to the optical functional surface of the optical element material. (For example, refer to Patent Document 1).

  In the method of manufacturing an optical element by press molding, there is a problem that after press molding, the optical element adheres to the mold and it is difficult to release the optical element from the mold. In order to solve this problem, Patent Document 1 discloses a technique that makes it easy to release the glass molded body from the mold by setting the periphery of the optical element in a reduced pressure state after press molding.

JP-A-8-81229

  When an optical element having a concave optical function surface is manufactured by press molding, that is, when the transfer surface of the mold is convex, the optical element and the transfer surface of the mold are in a vacuum state and are in close contact with each other. Not only is the heat shrinkage difference between the glass and the mold (metal), but the convex surface of the mold is clamped by the concave surface of the optical element, which makes it difficult to release the mold. It will contribute. When the optical element clamps the mold, the optical element cannot be released simply by reducing the pressure around the optical element as in Patent Document 1.

  The present invention has been made in view of the above, and in the case where an optical element having a concave optical functional surface is manufactured by press molding, the optical element can be easily released from a mold. An object is to provide a manufacturing method, a mold, and an optical element manufacturing apparatus.

  In order to solve the above-described problems and achieve the object, an optical element manufacturing method according to the present invention heats a mold provided with a convex region that is inverted with respect to the optical functional surface of the optical element. A pressing step for transferring the shape of the transfer surface to the material, and the mold and the optical element are cooled by bringing the transfer surface of the mold into contact with the heated optical element material and pressing it. A cooling step and a mold releasing step of releasing the material from the mold by setting the periphery of the mold to a reduced pressure state, and the pressing step projects the transfer surface against the material. Sealing in which gas is confined in at least one place by sequentially abutting at least one place on the outer peripheral side of the optical function surface from the center to the outer periphery of the region having a shape. Forming a space, that And features.

  The molding die according to the present invention is a molding die used in a method of manufacturing an optical element by press molding, and is a transfer provided with an optical functional surface reversal region having a convex shape that reverses the optical functional surface of the optical element. The transfer surface has an outer peripheral side than the optical function surface reversal region, and does not come into contact with the material of the optical element inside the range where the material of the optical element reaches during press molding. An escape portion is provided.

  In the above mold, the relief portion is a groove portion formed along the outer periphery of the optical function surface inversion region.

  In the molding die, the width of the groove is not uniform.

  In the molding die, the opening end surface of the groove is provided in a direction orthogonal to a pressing direction with respect to the molding die.

  In the molding die, the opening end surface of the groove is provided in a direction parallel to a pressing direction with respect to the molding die.

  In the above mold, the relief portion is a recess formed in a region on the outer peripheral side of the optical function surface reversal region.

  In the molding die, the relief portion is a boundary where an end portion of the optical function surface inversion region is connected to a region on the outer peripheral side of the optical function surface inversion region.

  The molding die includes a first member provided with the optical function surface inversion region of the transfer surface, and a second member provided with an outer peripheral region of the optical function surface inversion region of the transfer surface. And.

  The optical element manufacturing apparatus according to the present invention includes the molding die, a second molding die paired with the molding die, a molding chamber in which the molding die and the second molding die are disposed, and the molding A holder for holding the mold; a pedestal for fixing the second mold; a heating means for heating the mold and the second mold; and a pressing means for pressing the holder toward the pedestal. And a decompression means for decompressing the molding chamber.

  According to the present invention, in the pressing step, at least 1 is obtained by sequentially bringing the transfer surface of the mold into contact with the material of the optical element so as to be discontinuous at least at one location on the outer peripheral side of the optical function surface. Since a sealed space in which gas is confined is formed at a location, by reducing the pressure around the mold during the mold release process, the sealed space becomes relatively positive pressure, and the force for pushing the optical element from the mold is increased. Arise. Therefore, the optical element can be easily separated from the mold.

FIG. 1 is a schematic diagram showing a configuration example of an optical element manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing an example of an optical element manufactured by the optical element manufacturing apparatus shown in FIG. FIG. 3 is a schematic view showing one mold shown in FIG. FIG. 4 is a flowchart showing a method for manufacturing the optical element according to Embodiment 1 of the present invention. FIG. 5A is a schematic diagram for explaining the method of manufacturing the optical element according to Embodiment 1 of the present invention. FIG. 5B is a schematic diagram for explaining the method of manufacturing the optical element according to Embodiment 1 of the present invention. FIG. 5C is a schematic diagram for explaining the manufacturing method of the optical element according to Embodiment 1 of the present invention. FIG. 5D is a schematic diagram for explaining the manufacturing method of the optical element according to Embodiment 1 of the present invention. FIG. 5E is a schematic view for explaining the method for manufacturing the optical element according to Embodiment 1 of the present invention. FIG. 5F is a schematic diagram for explaining the manufacturing method of the optical element according to Embodiment 1 of the present invention. FIG. 6 is a cross-sectional view showing a press molding process of an optical element material using the molding die shown in FIG. FIG. 7 is an enlarged view of region A shown in FIG. FIG. 8A is a cross-sectional view showing a press molding process of an optical element material using a general mold. FIG. 8B is a cross-sectional view showing a press molding process of an optical element material using a general mold. FIG. 9 is a schematic diagram showing a mold according to Modification 1 of Embodiment 1 of the present invention. FIG. 10 is a schematic diagram showing a mold according to Modification 2 of Embodiment 1 of the present invention. FIG. 11 is a schematic diagram showing a mold according to Embodiment 2 of the present invention. FIG. 12 is a cross-sectional view showing a state where the optical element material is press-molded by the molding die shown in FIG. FIG. 13 is a schematic diagram showing a mold according to Embodiment 3 of the present invention. FIG. 14 is a schematic diagram showing a mold according to Embodiment 4 of the present invention.

  Hereinafter, an optical element manufacturing method and a manufacturing apparatus according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. Moreover, in description of each drawing, the same code | symbol is attached | subjected and shown to the same part.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration example of an optical element manufacturing apparatus according to Embodiment 1 of the present invention. An optical element manufacturing apparatus 1 shown in FIG. 1 is an apparatus that manufactures an optical element by so-called press molding, in which a thermoplastic optical element material such as glass is pressed while being heated using a molding die. A pair of molding dies 11 and 12 (first and second molding dies) for pressing the optical element material 100, a holder 13 for holding the upper molding die 11, and a lower molding die 12 are molded into the molding chamber. 10, a pedestal 14 to be fixed in the mold 10, cartridge heaters 15 and 16 provided inside the molds 11 and 12, lamp heaters 17 and 18 provided around the molds 11 and 12, and a holder 13, respectively. A cylinder 19 as pressing means for pressing the molding die 11 toward the molding die 12 and a vacuum pump 20 as decompression means for decompressing the interior of the molding chamber 10. Each of the molds 11 and 12 is provided with a temperature sensor (not shown) such as a thermocouple.

  As the optical element material 100, a glass material for press molding whose both end faces are polished in advance is used. Such an optical element material 100 is called a preform. By transferring the shape of the transfer surfaces of the molds 11 and 12 to both surfaces of the optical element material 100, an optical element having an optical functional surface that exhibits a lens function can be produced. Here, the optical functional surface is a range in which a light beam is actually allowed to pass when used in an optical system among optical elements such as lenses.

In the molding chamber 10, a carry-in / out port 21 through which the optical element material 100 is taken in and out, a gas introduction pipe 22 and a gas outlet pipe 23 for circulating an inert gas such as nitrogen gas (N ₂ ) in the molding chamber 10, A gas discharge pipe 24 that communicates the molding chamber 10 and the vacuum pump 20 is provided. The gas introduction pipe 22, the gas outlet pipe 23, and the gas discharge pipe 24 are provided with valves 22a, 23a, and 24a, respectively. By opening and closing these valves 22a, 23a, and 24a, the inside of the molding chamber 10 is provided. The atmosphere is adjusted.

  The molds 11 and 12 are formed of cemented carbide such as tungsten carbide (WC) or high hardness ceramics such as silicon carbide (SiC), and have transfer surfaces 11a and 12a finished by grinding and polishing, respectively.

  FIG. 2 is a cross-sectional view showing an example of an optical element manufactured by the optical element manufacturing apparatus 1 shown in FIG. In the optical element 110 shown in FIG. 2, the diameter of the optical functional surface 111 of one end surface is D1, and the diameter of the optical functional surface 112 of the other end surface is D2. When producing an optical element 110 in which one optical functional surface 111 has a concave shape and the other optical functional surface 112 has a convex shape, the transfer surface 11a of one molding die 11 has a concave shape with respect to the concave optical functional surface 111. An area having an inverted shape (that is, a convex shape) is provided, and an area having an inverted shape (that is, a concave shape) with respect to the convex optical function surface 112 is provided on the transfer surface 12a of the other mold 12.

  FIG. 3 is an enlarged schematic view of one mold 11 shown in FIG. 3A is a cross-sectional view of the mold 11, and FIG. 3B is a top view of the mold 11. As shown in FIG. 3, the transfer surface 11a of the mold 11 includes an optical function surface inversion region 11b having a shape inverted with respect to the concave optical function surface 111 of the optical element 110, and an outer peripheral side region 11c. Yes. The outer peripheral side region 11c is a region other than the optical function surface reversal region 11b in the transfer surface 11a.

  A circular groove 11d is formed in the outer peripheral region 11c so as to surround the optical function surface reversal region 11b as a relief portion that does not contact the optical element material 100 during press molding. In the first embodiment, the groove 11d is formed by drilling the outer periphery of the optical function surface inversion region 11b so that the depth direction is parallel to the central axis R.

  The position at which the groove 11d is provided is not particularly limited as long as it does not affect the optical functional surface of the completed optical element and the groove 11d is reliably sealed by the optical element material 100 when press molding. . That is, the outer peripheral side region 11c may be inside the range where the optical element material 100 reaches during press molding. The width of the groove 11d is not particularly limited as long as the softened optical element material 100 does not enter.

  The cartridge heaters 15 and 16 heat the molds 11 and 12 directly from the inside, respectively. The lamp heaters 17 and 18 have a substantially annular shape and are disposed so as to surround the molds 11 and 12, respectively. The lamp heaters 17 and 18 heat the molds 11 and 12 and heat the entire molding chamber 10.

  The cylinder 19 is an air cylinder, for example. By controlling the pressure of the air in the cylinder 19, the pressing force applied to the optical element material 100 by the molds 11 and 12 is adjusted.

  The vacuum pump 20 is used when the gas in the molding chamber 10 is replaced with nitrogen gas from the outside air (air), and when the pressure in the molding chamber 10 is reduced in a mold release step described later.

  Next, a method for manufacturing the optical element according to Embodiment 1 of the present invention will be described. FIG. 4 is a flowchart showing the method of manufacturing the optical element according to the first embodiment. 5A to 5F are schematic diagrams for explaining the method of manufacturing the optical element according to the first embodiment.

  First, in step S1, as shown in FIG. 5A, the optical element material 100 is placed on the mold 12. Specifically, the loading / unloading port 21 is opened, and the optical element material 100 is placed on the transfer surface 12a of the mold 12 using a robot hand or the like. As the optical element material 100, as described above, a glass preform whose both end faces have been polished in advance is used. In FIG. 5A, the plano-convex optical element material 100 is shown, but the shape of the optical element material 100 is not limited to the plano-convex shape, and may be, for example, spherical.

In the subsequent step S2, as shown in FIG. 5B, the air in the molding chamber 10 is replaced with nitrogen gas. That is, after operating the vacuum pump 20 to evacuate the molding chamber 10, the valve 22 a is opened and nitrogen gas (N ₂ ) is introduced from the gas introduction pipe 22. This is to prevent the molds 11, 12 and the like from being oxidized and deteriorated when the interior of the molding chamber 10 is heated in a later step. The oxygen concentration in the molding chamber 10 is preferably maintained at, for example, 5 ppm or less.

  In subsequent step S3, the mold heaters 11 and 12 are heated by energizing the cartridge heaters 15 and 16 and the lamp heaters 17 and 18. At this time, as shown in FIG. 5C, the valves 22 a and 23 a may be opened, and nitrogen gas may be circulated constantly in the molding chamber 10. The optical element material 100 is also heated by heat transfer from the heated molds 11 and 12.

  In the subsequent step S4, when the temperature reaches a temperature at which the optical element material 100 can be deformed (ie, the glass transition point or higher), the cylinder 19 is operated to turn the mold 11 into the mold 12 as shown in FIGS. 5D and 5E. The optical element material 100 is pressed by lowering it. Note that the temperature of the optical element material 100 can be estimated from the measured values of the temperature sensors provided in the molds 11 and 12.

  This pressing step is performed until the center thickness of the optical element material 100 reaches a predetermined thickness. The thickness of the optical element material 100 is controlled by the relative positional relationship between the mold 11 and the mold 12. In the case of the optical element manufacturing apparatus 1, since the position of the mold 12 is fixed, actually, the thickness of the optical element material 100 can be controlled by the amount of displacement of the mold 11 in the vertical direction.

  6 is an enlarged view of the optical element material 100 and the molds 11 and 12 shown in FIG. 5E, and FIG. 7 is an enlarged view of the region A shown in FIG. When pressing the transfer surface 11a of the mold 11 provided with the convex optical function surface reversal region 11b against the optical element material 100, first, the central portion of the transfer surface 11a contacts the optical element material 100, and from there The contact surface between the transfer surface 11a and the optical element material 100 gradually expands toward the outer periphery. The contact surface between the transfer surface 11a and the optical element material 100 is temporarily discontinuous in the groove portion 11d, but thereafter, both contact again in the outer peripheral side region 11c outside the groove portion 11d. Thereby, as shown in FIG. 7, gas is confined in the groove part 11d, and a sealed space is formed.

  In the subsequent step S5, the optical element material 100 and the molds 11 and 12 are cooled. Specifically, the outputs of the cartridge heaters 15 and 16 and the lamp heaters 17 and 18 are reduced, or the energization of these heaters is stopped. Thereby, the temperature of the optical element material 100 and the molds 11 and 12 gradually decreases toward room temperature.

  In the subsequent step S6, when the temperature reaches a temperature at which the optical element material 100 does not deform (that is, less than the glass transition point), as shown in FIG. 5F, the valves 22a and 23a are closed to stop the circulation of the nitrogen gas. Is operated to reduce the pressure in the molding chamber 10.

  In the subsequent step S7, the cylinder 19 is operated to raise the mold 11 and the press-molded optical element is released from the molds 11 and 12.

  In the subsequent step S8, the optical element is unloaded from the loading / unloading port 21. Thereby, an optical element having optical functional surfaces formed on both sides can be obtained.

  Next, the effect of forming the groove 11d in the mold 11 in the first embodiment will be described. 8A and 8B are cross-sectional views showing a press molding process of an optical element material using conventional molding dies 31 and 32. Among these, the upper mold 31 is provided with a convex transfer surface, and the lower mold 32 is provided with a concave transfer surface. When an optical element is manufactured by press molding, first, as shown in FIG. 8A, the optical element material 30 is pressed while being heated by the molds 31 and 32, thereby forming the molds 31 and 32 on the softened optical element material 30. Transfer the shape of the transfer surface. Then, the optical element material 30 and the molds 31 and 32 are cooled to cure the optical element material 30, and then the optical element material 30 is released from the molds 31 and 32.

Here, the linear expansion coefficient of tungsten carbide or silicon carbide used as the material of the molds 31 and 32 is about 3 to 7 × 10 ⁻⁶ (K ⁻¹ ). On the other hand, the linear expansion coefficient of glass is about 7 to 14 × 10 ⁻⁶ (K ⁻¹ ), which is very large with respect to the linear expansion coefficients of the molds 31 and 32. Thus, when a temperature change occurs in a state where materials having greatly different linear expansion coefficients are in contact with each other, as shown in FIG. 8B, the optical element material 30 with the larger linear expansion coefficient contracts significantly, Force to tighten in the direction is generated. That is, the concave surface of the optical element material 30 is in a state of strongly tightening the convex portion of the mold 31, and as a result, it is very difficult to release the optical element material 30 from the mold 31.

  On the other hand, as shown in FIGS. 6 and 7, when the groove 11d is provided on the transfer surface 11a of the mold 11, the softened optical element material 100 is pressed by the molds 11 and 12 (see step S4). The transfer surface 11a and the optical element material 100 are in close contact with each other around 11d. However, the optical element material 100 does not enter the groove 11d, and the groove 11d becomes a sealed space in which gas is confined.

  Thereafter, the optical element material 100 and the molds 11 and 12 are cooled (see step S5), and when the pressure in the molding chamber 10 is reduced (see step S6), the sealed space of the groove 11d is relative to the atmosphere in the molding chamber 10. Thus, a positive pressure state is generated, and a force for pushing the optical element material 100 from the mold 11 is generated. Thereby, the optical element material 100 can be easily released from the mold 11.

  As described above, according to Embodiment 1 of the present invention, when the optical element material 100 is press-molded, a sealed space is formed between the transfer surface 11a of the mold 11 and the optical element material 100. By depressurizing the interior of the molding chamber 10 after press molding, the optical element material 100 can be easily released from the mold 11.

(Modification 1)
Next, a first modification of the first embodiment of the present invention will be described. FIG. 9 is a schematic diagram showing a mold according to the first modification. As shown in FIG. 9, the molding die 26 according to the first modification has a transfer surface 26a including a convex optical function surface inversion region 26b and an outer peripheral side region 26c. A plurality (four in FIG. 9) of groove portions 26d are formed along the outer periphery of the optical function surface inversion region 26b in the outer periphery side region 26c. The number of these groove parts 26d and the length of each groove part 26d can be set arbitrarily.

  Also, the position of the groove 26d can be arbitrarily set. The groove 26d is not necessarily in contact with the outer periphery of the optical function surface reversal region 26b. If the inner side of the outer peripheral side region 26c reaches the optical element material 100 during press molding, the optical function surface reversal region You may form in the position away from the outer periphery of 26b.

  The end face shape of the groove 26d is not necessarily a circular or arcuate groove along the outer periphery of the optical function surface reversal region 26b, but may be a recess having an arbitrary end face shape.

(Modification 2)
Next, a second modification of the first embodiment of the present invention will be described. FIG. 10 is a schematic diagram showing a mold according to the second modification. As shown in FIG. 10, the mold 27 according to the second modification has a transfer surface 27a including a convex optical function surface inversion region 27b and an outer peripheral region 27c. A groove portion 27d is formed in the outer peripheral region 27c along the optical function surface inversion region 27b.

  The groove portion 27d is provided such that the inner circumference is centered on the central axis R and the outer circumference is eccentric with respect to the central axis R. Thus, by making the width of the groove 27d asymmetrical or non-uniform, when the pressure inside the molding chamber 10 is reduced and the optical element material 100 is released (see FIG. 5F), the groove becomes a relatively positive pressure. An asymmetric pushing force is generated with respect to the central axis R from the sealed space 27d. As a result, the optical element material 100 can be easily released from the mold 27 by the action of the bias load.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. FIG. 11 is a schematic view showing a mold according to the second embodiment. As shown in FIG. 11, the mold 40 according to the second embodiment is a transfer including an optical function surface inversion region 40b and an outer peripheral region 40c having a shape (convex shape) inverted with respect to a concave optical function surface. It has surface 40a. Among these, the outer periphery side area | region 40c has comprised planar shape. The end portion of the optical function surface inversion region 40b is connected to the outer peripheral side region 40c so as to be substantially orthogonal at the boundary 40d. This boundary 40d becomes an escape portion that does not come into contact with the optical element material 100 during press molding.

  FIG. 12 is a cross-sectional view showing a state where the optical element material 100 is press-molded by the molding die 40. As shown in FIG. 12, when the transfer surface 40a of the mold 40 is pressed against the optical element material 100, first, the central portion of the optical function surface inversion region 40b comes into contact with the optical element material 100, and from there to the outer peripheral portion. The contact surface between the transfer surface 40a and the optical element material 100 gradually expands. However, as described above, since the end portion of the optical function surface inversion region 40b is connected so as to be substantially orthogonal to the outer peripheral region 40c, the optical element material 100 is placed in the boundary 40d or a corner region in the vicinity thereof. Prior to entering, it comes into contact with the outer peripheral region 40c. As a result, a sealed space 40e in which a gas is confined around the boundary 40d is formed.

  Note that the connection angle θ between the end of the optical function surface reversal region 40b and the outer peripheral region 40c is not limited to 90 °, and may be an acute angle or a slightly obtuse angle. Further, a radius may be provided at the boundary 40d. In short, from the relationship with the viscosity of the softened optical element material 100, an angle at which the optical element material 100 contacts the outer peripheral region 40c before reaching the boundary 40d may be used.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. FIG. 13 is a schematic diagram showing a mold according to the third embodiment. As shown in FIG. 13, the molding die 50 according to the third embodiment surrounds the first member 51 provided with the convex optical function surface inversion region 51a and the optical function surface inversion region 51a. And a second member 52 fitted into the first member 51. Of the second member 52, the end surface 52a located on the outer peripheral side of the optical function surface inversion region 51a and the optical function surface inversion region 51a serve as a transfer surface 50a that comes into contact with the optical element material 100 during press molding. .

  Thus, by forming the mold 50 by combining a plurality of members, the connection angle θ between the end of the optical function surface reversal region 51a and the end surface 52a can be reduced (for example, 90 ° or less). .

(Modification 3)
As a third modification of the third embodiment described above, the groove portion can be formed in the same manner as in the first embodiment by making the inner diameter of the second member 52 larger than the outer diameter of the optical function surface inversion region 51a. is there.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. FIG. 14 is a schematic diagram showing a mold according to the fourth embodiment. As shown in FIG. 14, the mold 60 according to the fourth embodiment has a transfer surface 60a including a convex optical function surface inversion region 60b and an outer peripheral region 60c. The transfer surface 60a is provided with a groove 60d formed by drilling the outer periphery of the optical function surface inversion region 60b so that the depth direction is perpendicular to the central axis R. The groove 60d is an escape portion that does not contact the optical element material during press molding. The groove 60d does not affect the optical function surface of the completed optical element as long as at least the opening end surface is located on the outer periphery of the optical function surface inversion region 60b.

  In such a mold 60, since the opening end surface of the groove 60d is substantially parallel to the pressing direction (see the white arrow in FIG. 5D) at the time of press forming, the opening surface of the groove is perpendicular to the pressing direction. In comparison, the optical element material is less likely to enter the groove 60d.

  Here, when the pressure in the molding chamber 10 (see FIG. 1) is reduced and the optical element material 100 is released from the mold (see FIG. 5F), the optical element material 100 is more increased in the opening area of the groove. Since the force which extrudes from a shaping | molding die becomes large, it is preferable. Therefore, by providing the opening surface of the groove portion 60d substantially parallel to the pressing direction, the opening area of the groove portion 60d can be increased. Therefore, it becomes possible to release the optical element material 100 more easily.

  In the fourth embodiment, as in the third embodiment, the molding die 60 may be configured by a plurality of members. As an example, the transfer surface 60a including the optical function surface reversal region 60b and the outer peripheral side region 60c may be formed by integrating a hemispherical member with one end surface of a cylindrical member by screwing or the like. Further, the depth direction of the groove 60d may be a direction orthogonal to the central axis R or a direction inclined with respect to the central axis R.

  In Embodiments 1 to 4 and Modifications 1 to 3 described above, a so-called uniaxial optical element that sequentially performs a heating process, a press molding process, a cooling process, and a release process on one stage in the molding chamber. The manufacturing apparatus has been described as an example. However, in the first to fourth embodiments and the modified examples, the molding die in which the optical element material is set is sequentially transported to a plurality of stages, and the heating process, the press molding process, the cooling process, the mold release are performed at the transport destination stage. You may apply to what is called a circulation type optical element manufacturing apparatus which performs each process (for example, refer Unexamined-Japanese-Patent No. 2005-126325).

  The present invention described above is not limited to the first to fourth embodiments and the first to third modifications, and can be variously modified according to specifications and the like, for example, the first to fourth embodiments and the first to fourth embodiments described above. You may exclude and form some components from all the components shown by the modifications 1-3. It is apparent from the above description that various other embodiments are possible within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Optical element manufacturing apparatus 10 Molding chamber 11, 12 Mold 11a, 12a, 26a, 27a, 40a, 50a, 60a Transfer surface 11b, 26b, 27b, 40b, 51a, 60b Optical function surface inversion area | region 11c, 26c, 27c, 40c, 60c Outer peripheral region 11d, 26d, 27d, 60d Groove 13 Holder 14 Pedestal 15, 16 Cartridge heater 17, 18 Lamp heater 19 Cylinder 20 Vacuum pump 21 Loading / unloading port 22 Gas inlet tube 22a, 23a, 24a Valve 23 Gas outlet Pipe 24 Gas exhaust pipe 26, 27, 31, 32, 40, 50, 60 Mold 40d Boundary 40e Sealed space 51 First member 52 Second member 52a End face 100 Optical element material 110 Optical element 111, 112 Optical function surface

Claims (10)

By heating the mold provided with a convex region that is reversed with respect to the optical function surface of the optical element, and pressing the transfer surface of the mold against the heated optical element material, A pressing step for transferring the shape of the transfer surface to the material;
A cooling step for cooling the mold and the optical element;
A mold releasing step in which the periphery of the mold is reduced in pressure and the material is released from the mold;
Including
In the pressing step, the transfer surface with respect to the material is discontinuous at least at one location on the outer peripheral side of the optical function surface from the central portion to the outer peripheral portion of the convex region. By sequentially abutting, a sealed space in which gas is confined in at least one place is formed.
A method for manufacturing an optical element. A mold used in a method of manufacturing an optical element by press molding,
A transfer surface provided with an optical function surface inversion region having a convex shape that is inverted with respect to the optical function surface of the optical element;
A relief portion that does not contact the material of the optical element is provided on the transfer surface, on the outer peripheral side of the optical function surface reversal region, and inside the range where the material of the optical element reaches during press molding. ing,
A mold characterized by that.   The mold according to claim 2, wherein the escape portion is a groove portion formed along an outer periphery of the optical function surface inversion region.   The mold according to claim 3, wherein the groove has a non-uniform width.   The mold according to claim 3, wherein the opening end face of the groove is provided in a direction orthogonal to a pressing direction with respect to the mold.   The mold according to claim 3, wherein the opening end face of the groove is provided in a direction parallel to a pressing direction with respect to the mold.   The mold according to claim 2, wherein the escape portion is a recess formed in a region on an outer peripheral side of the optical function surface inversion region.   The mold according to claim 2, wherein the escape portion is a boundary where an end portion of the optical function surface inversion region is connected to a region on an outer peripheral side of the optical function surface inversion region. A first member provided with the optical function surface reversal region of the transfer surface;
A second member provided with an outer peripheral side region of the optical function surface reversal region of the transfer surface;
The mold according to any one of claims 2 to 8, further comprising: The mold according to any one of claims 2 to 9,
A second mold paired with the mold;
A molding chamber in which the mold and the second mold are disposed;
A holder for holding the mold;
A base for fixing the second mold;
Heating means for heating the mold and the second mold;
Pressing means for pressing the holder toward the pedestal;
Decompression means for decompressing the molding chamber;
An optical element manufacturing apparatus comprising:

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