CN115806380B - Glass lens forming die - Google Patents
Glass lens forming die Download PDFInfo
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- CN115806380B CN115806380B CN202310012251.0A CN202310012251A CN115806380B CN 115806380 B CN115806380 B CN 115806380B CN 202310012251 A CN202310012251 A CN 202310012251A CN 115806380 B CN115806380 B CN 115806380B
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- mold
- die
- glass
- molding
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
- C03B11/06—Construction of plunger or mould
- C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
A glass lens molding die is provided with: a cylindrical mold; a die base material inserted into the cylindrical die so as to be movable in a die moving direction, the die base material having a base material side contact portion at one end; a glass molding die having a molding surface and a die-side contact portion, wherein the molding surface forms one lens surface of the glass lens, and the die-side contact portion is capable of approaching or separating from the base-side contact portion; and an opposing mold having a second molding surface that forms the other lens surface of the glass lens. At least one of the substrate-side abutting portion and the mold-side abutting portion has a core adjusting surface which is a part of a conical surface centered on an axis extending in the mold moving direction, and the glass forming mold is held at a fixed position with respect to the mold substrate in the mold moving direction and in a direction perpendicular to the mold moving direction by abutting of the substrate-side abutting portion and the mold-side abutting portion.
Description
The application relates to a split application of Chinese patent application with the application number 201980035739.7 and the application date 2019, 6 and 3, and the name of the application is 'glass lens forming die'.
Technical Field
The invention relates to a forming die for forming a glass lens.
Background
In the manufacture of glass lenses, the following methods have been used previously: the glass as a material is formed into an approximate shape, and then is finished by grinding or lapping. In recent years, a method of manufacturing a glass lens without grinding or polishing by press molding a glass in a heated and softened state by a mold for molding (hereinafter referred to as a molding mold) has been put into practical use (for example, patent document 1). By molding using such a molding die, not only spherical lenses, aspherical lenses of complex shape, and the like, but also mass production can be performed at low cost.
In extrusion molding, the surface shape (molding surface) of a molding die is transferred to a molded object, and therefore, the accuracy of the molding die is extremely required. For example, the molding die is required to have high rigidity and heat resistance so that deformation due to load or heat applied during extrusion does not occur. In addition, in order to prevent the object from adhering to the molding die or cracking of the object, the molding die needs to have an appropriate thermal expansion coefficient with respect to the object.
As a molding die satisfying the above conditions, a molding die made of metal, ceramic, or the like is widely used. However, such a molding die is expensive and laborious to manufacture separately by cutting or the like while suppressing variation in accuracy. In particular, in the case of mass-producing glass lenses for optical devices, a large number of molding dies are required. As a countermeasure for this, a technique using a molding die made of glass has been proposed (for example, patent documents 2 and 3).
Specifically, a master mold (female mold) having a molding surface as a reference is prepared, and a glass material for a molding mold that is softened by heating is extruded by the master mold, whereby a molding mold made of glass (hereinafter referred to as a glass molding mold) to which the molding surface of the master mold is transferred can be obtained. The glass forming die has the following advantages: once the master mold is manufactured with high precision, mass production is easy and the degree of freedom in shape setting is high.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 6-127956
Patent document 2: japanese patent No. 2616964
Patent document 3: japanese patent laid-open No. 2-102136
Disclosure of Invention
(Technical problem to be solved by the invention)
As a problem of the glass molding die, it is difficult to secure heat resistance and impact resistance against external impact at the time of repeating molding in a high temperature state, and it is desired to improve durability, as compared with the metal or ceramic molding die. As a countermeasure for this, in patent document 3, a joined body made of metal or ceramic having a thermal expansion coefficient (linear expansion coefficient) substantially equal to that of a material glass constituting a glass molding die is joined to the glass molding die to integrate the joined body.
However, the constitution of joining a joined body made of other materials with respect to a glass-making forming die requires that the thermal expansion rate of the joined body is the same as that of the glass-making forming die, and therefore, the degree of freedom in material selection is low. Further, since it is difficult to completely match the thermal expansion coefficients of the glass molding die and the joined body, it is unavoidable that a pressure is applied to the joined portions due to the difference in thermal expansion coefficient when heating is performed in a state where the glass molding die and the joined body are integrated by joining. Further, when integrating the glass molding die with the joined body, it is necessary to match the center axis of the glass molding die (the optical axis of the lens molded by the glass molding die) with the center axis of the joined body with high accuracy, and the difficulty, effort, and cost of manufacturing are high.
Patent document 1 describes the following technique: the cavity mold and the metal mold are combined to form a forming mold, the cavity mold is provided with a cavity surface for forming the glass lens, and the metal mold is made of a material with a linear expansion coefficient smaller than that of the cavity mold. The die has a tapered hole with a cross section, which gradually increases in diameter as it advances toward the tip end side (the side having the molding surface) of the cavity die, and the hole is fitted into the cavity die. The inner peripheral surface of the hole of the die and the peripheral surface of the cavity die are formed as tapered surfaces that overlap each other in a slidable manner, and the cavity die and the central axis of the die can be prevented from being deviated in the overlapping state of the tapered surfaces. However, since the cavity mold and the mold are not joined, the cavity mold may be separated from the mold in a state where the molding mold is separated, and the practicality is low.
The present invention has been made in view of the above problems, and an object thereof is to provide a glass lens molding die having high productivity, high durability, high precision, and excellent practicality.
(Technical means for solving the technical problems)
The glass lens molding die for extrusion molding of a glass lens according to the present invention comprises: a cylindrical mold having an inner space extending in a mold moving direction; a mold base material made of metal or ceramic, which is inserted into the inner space of the cylindrical mold so as to be movable in the mold moving direction, and which has a base material side contact portion at one end in the mold moving direction; a glass molding die made of glass having a higher glass transition temperature than glass to be molded, which is a material of a glass lens, and having a molding surface forming one lens surface of the glass lens and a die-side contact portion facing an opposite side of the molding surface in a die moving direction and being capable of approaching or separating from the base-side contact portion; and a facing mold having a second molding surface which is capable of moving relative to the glass molding mold in a mold moving direction, the second molding surface facing the molding surface of the glass molding mold to form the other lens surface of the glass lens. At least one of the substrate-side abutting portion and the mold-side abutting portion has a core adjusting surface which is a part of a conical surface centered on an axis extending in the mold moving direction, and the glass forming mold is held at a fixed position with respect to the mold substrate in the mold moving direction and in a direction perpendicular to the mold moving direction by abutting of the substrate-side abutting portion and the mold-side abutting portion. Further, the glass forming mold has a regulated surface around the forming surface, and a regulating surface facing the regulated surface in the mold movement direction is provided inside the cylindrical mold, and by the abutment of the regulated surface against the regulating surface, the movement amount of the glass forming mold relative to the cylindrical mold in the direction in which the mold-side abutment portion is separated from the substrate-side abutment portion can be regulated.
Preferably, the restricting surface and the restricted surface are each formed of a part of a conical surface common to the aligning surface as a central axis. In this way, the stability of the glass forming mold with respect to the mold base material can be improved in a state where the restricting surface is in contact with the restricted surface.
The restricting surface is set to be separated from the restricting surface in a state where the glass lens is extruded between the molding surface and the second molding surface. Thus, the restriction surface and the restricted surface do not affect the positional accuracy of the glass molding die and the opposing die during extrusion molding.
The opposing mold may be composed of a second mold base made of metal or ceramic and a second glass-made molding mold made of glass having a higher glass transition temperature than the glass to be molded, which is a material of the glass lens. The second mold base material is inserted into the inner space of the cylindrical mold so as to be movable in the mold moving direction, and has a second base material side abutting portion at one end in the mold moving direction. The second glass forming mold has a second molding surface and a second mold-side abutment portion that faces an opposite side of the second molding surface in a mold moving direction and is capable of approaching or separating with respect to the second base-side abutment portion. At least one of the second base material side contact portion and the second mold side contact portion has a core adjustment surface which is a part of a conical surface centered on the axis, and the second glass forming mold can be held at a fixed position with respect to the second mold base material in the mold moving direction and in a direction perpendicular to the mold moving direction by the contact of the second base material side contact portion and the second mold side contact portion.
(Effects of the invention)
According to the glass lens molding die of the present invention described above, the portion having the molding surface for molding the lens surface of the glass lens is used as the glass molding die, and the metal or ceramic mold base material that is in contact with the glass molding die is supported so as to be movable in the cylindrical die. Therefore, a glass molding die can be mass-produced at low cost, and durability can be improved by a die base material excellent in heat resistance and impact resistance. Further, since the glass molding die and the die base material are not bonded and fixed but the relative positions are determined by the contact of the contact portions with each other, it is difficult to apply a load due to the difference in the thermal expansion coefficients of the glass molding die and the die base material, and it is possible to obtain high-precision die accuracy, and at the same time, the degree of freedom in selecting the materials of the glass molding die and the die base material is high. Further, since the glass molding die has the limiting surface and the limited surface for limiting the movement amount of the glass molding die in the direction of separating from the die base material, the glass molding die and the die base material are not fixed, but the glass molding die is easy to handle and handle, and excellent practicality can be obtained.
Drawings
Fig. 1 is a sectional view showing a state of preparation for extrusion molding of the glass lens molding die of the present embodiment.
Fig. 2 is a sectional view showing a state in which extrusion molding of the glass lens molding die is completed.
Fig. 3 is a sectional view showing a step of separating the upper die unit from the lower die unit after the completion of extrusion molding and taking out the molded glass lens.
Description of the reference numerals
10: Glass lens forming die
11: Upper die unit
12: Lower die unit (opposite die)
13: Glass preform
14: Glass lens
14A, 14b: lens surface
14C: edge part (コ A)
15. 17: Suction source
20: Cylindrical die
21: Upper inner face
22: Lower inner face
23: Upper die limiting surface
24: Protruding part
30: Upper die base material (die base material)
31: Sliding guide surface
32: Core adjusting surface (base material side abutting part)
33: Bottom surface
34: Suction hole
40: Upper mould (glass forming mould)
41: Molding surface
42: Restricted surface
43: Step part
45: Core adjusting surface (die side abutting part)
50: Lower mould base material (second mould base material)
51: Large diameter portion
52: Small diameter portion
53: Sliding guide surface
54: Core adjusting surface (second base side abutting part)
57: Suction hole
60: Lower mould (second glass forming mould)
61: Forming surface (second forming surface)
62: Annular protruding part
63: Core adjusting surface (second mould side abutting part)
64: An outer peripheral surface
70. 71: Driving device
S: interior space
X: reference shaft (axis).
Detailed Description
In the glass lens molding die 10 of the present embodiment, the upper die unit 11 and the lower die unit (opposing die) 12 are moved relatively along the reference axis (axis line) X, and the glass preform 13 (fig. 1) which is the glass to be molded before molding is subjected to press processing, thereby molding the glass lens 14 (fig. 2 and 3).
As shown in fig. 3, the glass lens 14 is an aspherical lens in which both lens surfaces 14a and 14b are aspherical, and one lens surface 14a is concave and the other lens surface 14b is convex. An annular edge portion 14c is formed on the periphery of the glass lens 14.
The glass lens forming mold 10 is provided with a cylindrical mold 20, and the cylindrical mold 20 guides the upper mold unit 11 and the lower mold unit 12. The upper mold unit 11 includes an upper mold base (mold base) 30 and an upper mold (glass molding mold) 40. The lower mold unit 12 includes a lower mold base material (second mold base material) 50 and a lower mold (second glass forming mold) 60. The upper mold 40 and the lower mold 60 are made of glass satisfying the conditions described below. The cylindrical die 20 and the upper die base 30 and the lower die base 50 are made of a material other than glass, specifically, a ceramic such as silicon carbide (SiC) or silicon nitride (Si 3N4) or a metal such as a cemented carbide.
The reference axis X coincides with the optical axis of the glass lens 14 molded by the glass lens molding die 10. The upper die 40 and the lower die 60 are extrusion molded in a state of being positioned (centered) via the upper die base 30 and the lower die base 50 so that the central axes thereof coincide with the reference axis X. Details of this positioning will be described later. In the following description, the direction along the reference axis X is referred to as the up-down direction (mold moving direction), and the direction perpendicular to the reference axis X is referred to as the radial direction.
The cylindrical mold 20 is a cylindrical body surrounding the reference axis X, and has an inner space S (fig. 3) penetrating in the vertical direction inside. An upper inner surface 21 is formed in a predetermined range in the up-down direction from the upper end side and a lower inner surface 22 is formed in a predetermined range in the up-down direction from the lower end side inside the cylindrical mold 20. The upper inner surface 21 and the lower inner surface 22 are cylindrical surfaces (inner surfaces of the cylinder) centered on the reference axis X, respectively, and the inner diameter of the upper inner surface 21 is larger than the inner diameter of the lower inner surface 22.
An upper die regulating surface (regulating surface) 23 is provided between the upper inner surface 21 and the lower inner surface 22 in the cylindrical die 20. More specifically, the cylindrical die 20 is provided with a projection 24 projecting in the inner diameter direction continuously in the circumferential direction, and the upper die limiting surface 23 is formed on the projection 24. The upper die limiting surface 23 is a part of a conical surface (inner surface of a cone) centered on the reference axis X, and the diameter thereof decreases as it advances downward. That is, the upper die limiting surface 23 is formed in a tapered shape in which the protruding amount to the inner diameter side increases as it moves away from the upper inner surface 21 and advances downward.
A through hole 25 is formed in a lower end portion (upper portion of the protruding portion 24) of the upper inner surface 21, and the through hole 25 penetrates the cylindrical die 20 in the radial direction. A through hole 26 is formed in an upper end portion (lower portion of the protruding portion 24) of the lower inner surface 22, and the through hole 26 penetrates the cylindrical die 20 in the radial direction.
The upper mold base 30 is inserted into the cylindrical mold 20 so as to be movable in the up-down direction. A cylindrical slide guide surface 31 is formed on the outer surface of the upper die base 30, and the slide guide surface 31 has an outer diameter corresponding to the inner diameter of the upper inner surface 21. By the abutment of the upper inner surface 21 and the slide guide surface 31, the central axes of the cylindrical mold 20 and the upper mold base 30 coincide with each other. The central axes of the cylindrical mold 20 and the upper mold base 30 coincide with the reference axis X. The slide guide surface 31 is supported slidably in the up-down direction on the upper inner surface 21 so as not to be inclined or rattled. A rotation restricting structure may be provided between the cylindrical mold 20 and the upper mold base 30 to prevent relative rotation between the cylindrical mold 20 and the upper mold base 30 in the circumferential direction around the reference axis X.
The glass lens forming mold 10 has a driving device 70 and a driving device 71, the driving device 70 moves the upper mold base material 30 relative to the cylindrical mold 20 in the up-down direction, and the driving device 71 moves the lower mold base material 50 relative to the cylindrical mold 20 in the up-down direction.
A core alignment surface (substrate-side contact portion) 32 and a bottom surface 33 are formed at the lower end (one end in the mold moving direction) of the upper mold substrate 30. The aligning surface 32 is a part of a conical surface (inner surface of a cone) centered on the reference axis X, and the diameter thereof decreases as it advances upward. The bottom surface 33 is a flat surface that blocks the upper end of the cored-out surface 32. The lower end of the upper mold base 30 is formed into a concave portion in a mortar shape by the tapered aligning surface 32.
A suction hole 34 penetrating in the vertical direction is formed in the upper die base 30. The center line of the suction hole 34 substantially coincides with the reference axis X. The lower end of the suction hole 34 opens to the center of the bottom surface 33. The upper end of the suction hole 34 opens to the upper end surface of the mold base 30, and is connected to the suction pipe 16 extending from the suction source 15.
When molding is performed in the completed state (fig. 1) of the glass lens molding die 10, vacuum gas substitution is performed. At this time, the suction source 15 is driven, and air between the bottom surface 33 of the upper die base 30 and the upper surface 44 of the upper die 40 is discharged through the suction pipe 16 and the suction hole 34. Further, by using the suction structure from the suction source 15 to the suction hole 34, the suction force of the suction holding upper die 40 can be applied to the concave portion (the region surrounded by the aligning surface 32 and the bottom surface 33) of the lower end of the upper die base 30.
The lower die base material 50 has a large diameter portion 51 and a small diameter portion 52, and the small diameter portion 52 is smaller than the large diameter portion 51 and protrudes upward from the large diameter portion 51. The large diameter portion 51 has substantially the same outer diameter dimension as the cylindrical die 20. A cylindrical sliding guide surface 53 is formed on the outer surface of the small diameter portion 52, and the sliding guide surface 53 has an outer diameter corresponding to the inner diameter of the lower inner surface 22 of the cylindrical die 20.
The lower die base 50 can be inserted into and removed from the cylindrical die 20 from below the small diameter portion 52. In a state where the small diameter portion 52 is inserted into the cylindrical die 20, concentricity of the cylindrical die 20 and the lower die base material 50 (the central axis of the lower die base material 50 coincides with the reference axis X) can be maintained by abutment of the lower inner surface 22 with the slide guide surface 53. The slide guide surface 53 is supported on the lower inner surface 22 so as to be slidable in the up-down direction without tilting or rocking. A rotation restricting structure may be provided between the cylindrical die 20 and the lower die base material 50 to prevent relative rotation between the cylindrical die 20 and the lower die base material 50 in the circumferential direction around the reference axis X.
The maximum insertion amount of the small diameter portion 52 into the cylindrical mold 20 is determined by the abutment of the lower end of the cylindrical mold 20 against the large diameter portion 51 (see fig. 1 and 2). In this maximum inserted state, the upper end of the small diameter portion 52 is located below the through hole 26. That is, the through-holes 26 and the through-holes 25 above the through-holes are not blocked by the lower die base material 50.
A core adjustment surface (second substrate side contact portion) 54, a recess 55, and an inner peripheral surface 56 are formed at the upper end (one end in the mold moving direction) of the lower mold substrate 50. The aligning surface 54 is a part of a conical surface (inner surface of a cone) centered on the reference axis X, and has a diameter that decreases as it advances downward. The recess 55 is recessed further downward from the center of the aligning surface 54. The inner peripheral surface 56 is a cylindrical surface (inner surface of a cylinder) centered on the reference axis X, and protrudes upward from the upper end edge of the aligning surface 54. The upper end of the lower die base material 50 is formed as a mortar-shaped concave portion having a tapered aligning surface 54 on the inner surface.
The lower die base 50 is formed with a suction hole 57 penetrating in the vertical direction. The center line of the suction hole 57 substantially coincides with the reference axis X. The upper end of the suction hole 57 opens to the bottom center of the recess 55, and the lower end of the suction hole 57 is connected to the suction tube 18 extending from the suction source 17.
When the vacuum gas is replaced in the completed state (fig. 1) of the glass molding die 10, the suction source 17 is driven, and air between the concave portion 55 of the lower die base material 50 and the lower die 60 is discharged through the suction pipe 18 and the suction hole 57. Further, by using the suction structure from the suction source 17 to the suction hole 57, the suction force of the suction holding lower die 60 can be applied to the upper end portion (concave portion surrounded by the aligning surface 54, the concave portion 55, and the inner peripheral surface 56) of the small diameter portion 52.
The upper mold 40 and the lower mold 60 have a molding surface 41 and a molding surface (second molding surface) 61 on the sides facing each other. In the upper die 40, the side having the molding surface 41 is set as the front surface side, and the opposite side is set as the back surface side. Similarly, in the lower die 60, the side having the molding surface 61 is set as the front surface side, and the opposite side is set as the back surface side. The molding surface 41 and the molding surface 61 are aspherical surfaces having shapes corresponding to the one lens surface 14a and the other lens surface 14b of the glass lens 14, respectively. The molding surface 61 has a cylindrical surface portion corresponding to the edge portion 14c at a peripheral edge of a concave surface portion corresponding to the convex shape of the lens surface 14 b. The present invention is also applicable to molding of glass lenses other than the illustrated glass lens 14, and the shapes of the molding surface 41 and the molding surface 61 can be appropriately set according to the lens shape.
A coating layer (not shown) may be formed on the molding surface 41 and the molding surface 61. The coating layer is formed of a carbon film or the like, and has an effect of suppressing melting of the glass to be molded constituting the glass lens 14. The coating layer may have a single-layer structure or a multilayer structure having different compositions. Alternatively, the molding surface 41 and the molding surface 61 may be exposed without the coating layer.
A restricted surface 42 is formed around the molding surface 41 on the surface side of the upper die 40. The regulated surface 42 is a part of a conical surface (outer surface of a cone) centered on the reference axis X, and the diameter thereof decreases as it advances downward. An annular step 43 centered on the reference axis X is formed between the molding surface 41 and the regulated surface 42.
An upper surface 44 located on the back side of the molding surface 41 and a core adjustment surface (mold side contact portion) 45 located on the back side of the regulated surface 42 are formed on the back side of the upper mold 40. The aligning surface 45 is a part of a conical surface (outer surface of a cone) centered on the reference axis X, and the diameter thereof decreases as it advances upward. The core surface 45 is a part of the same (equal vertex angle) conical surface as the core surface 32 of the upper die base material 30.
A cylindrical outer peripheral surface 46 is further formed between the restricted surface 42 and the aligning surface 45 in the upper die 40. The outer diameter of the outer peripheral surface 46 is smaller than the inner diameter of the upper inner surface 21 of the cylindrical die 20, and the outer peripheral surface 46 is separated from the upper inner surface 21 in the radial direction in a positioned state of the upper die 40 described later.
The alignment surface 45 is brought into contact with the alignment surface 32, thereby determining the position of the upper die 40 relative to the upper die base 30. The aligning surface 32 and the aligning surface 45 are conical surfaces that can be brought into surface contact with each other, and come into contact with each other with the central axes (lines extending in the height direction of the cone and passing through the apex) thereof being aligned. By this abutment, the position of the upper die 40 in the up-down direction with respect to the upper die base material 30 is determined, and the position of the upper die 40 in the radial direction centered on the reference axis X is also determined. When the upper die 40 is positioned by the abutment of the aligning surface 32 and the aligning surface 45 in a state where the upper die base 30 is accommodated in the cylindrical die 20, the central axes of the upper die base 30 and the upper die 40 coincide with the reference axis X. That is, the upper die 40 is brought into a state of being properly cored with respect to the cylindrical die 20 and the upper die base material 30, and the reference axis X passes through the center of the molding surface 41.
In a positioned state of the upper mold 40 in which the aligning surface 32 is in contact with the aligning surface 45, a gap in the vertical direction exists between the bottom surface 33 and the upper surface 44. In this positioned state, a radial gap exists between the upper inner surface 21 and the outer peripheral surface 46. Thus, only the aligning surface 32 is positioned by directly abutting the upper die 40, and the positions other than the aligning surface 32 do not interfere with the positioning of the upper die 40.
As described above, the upper mold unit 11 is constituted by the upper mold base 30 made of non-glass (made of metal or ceramic) and the upper mold 40 made of glass. The upper mold 40 is a part of the upper mold unit 11 including a molding surface 41 for molding the glass lens 14, and the upper mold base 30 as the other part is formed of metal or ceramic having heat resistance and impact resistance superior to those of glass. In particular, since the upper die base material 30 is a portion that slides with respect to the cylindrical die 20 or receives a pressing force from the outside at the time of extrusion molding described later, it is effective to form it from a metal or ceramic having excellent mechanical strength, and the use of the upper die base material 30 helps to ensure the accuracy of the upper die unit 11.
The upper mold 40 may be formed in a small and simple shape dedicated to the molding surface 41 and its surroundings, and is easy to manufacture. More specifically, the upper mold 40 has a simple cross-sectional shape similar to a convex lens, and surrounds the molding surface 41 and the upper surface 44 on the front/rear surface by the conical restricted surface 42, the aligning surface 45, and the cylindrical outer peripheral surface 46. The wall thickness of the upper mold 40 from the molding surface 41 to the upper surface 44 is about a fraction of the size of the entire upper mold unit 11 in the up-down direction. Therefore, the amount of glass constituting the upper mold 40 is reduced, and the cost can be suppressed when manufacturing the upper mold 40. In addition, when the upper mold 40 is manufactured, shrinkage of glass due to cooling after molding is small, and accuracy control is easy.
The upper mold base 30 and the upper mold 40 are not fixed to each other by adhesion or the like, and are configured to position the upper mold 40 by abutment of the centering surface 32 and the centering surface 45 which can be brought into and out of contact with each other. Therefore, even if the thermal expansion coefficients of the materials constituting the upper mold base 30 and the upper mold 40 are different from each other, it is difficult to apply excessive stress to the boundary (contact) portion between them at the time of heating. That is, the allowable range of the thermal expansion coefficient of the material constituting the upper die base 30 and the upper die 40 is wider than the structure in which the upper die base 30 and the upper die 40 are fixed to each other, and the degree of freedom in selecting the material is improved.
The upper die 40 is located below the upper die base 30, and the aligning surfaces 32 and 45 are conical surfaces each having a diameter that increases as the surfaces progress downward. Therefore, the upper die base material 30 does not restrict the downward movement of the upper die 40 (the direction in which the aligning surface 45 separates from the aligning surface 32).
The downward movement amount of the upper die 40 is regulated by the upper die regulating surface 23 provided on the cylindrical die 20. That is, the upper die 40 is prevented from falling down. The upper die regulating surface 23 is provided at a position opposed to the regulated surface 42 of the upper die 40 in the up-down direction, and the regulated surface 42 abuts against the upper die regulating surface 23 when the upper die 40 moves downward in the cylindrical die 20 (fig. 3). The molding surface 41 and the step 43 of the upper mold 40 have diameters that can pass through the inner side of the upper mold limiting surface 23, and can protrude downward from the protruding portion 24 (see fig. 2 and 3).
An annular projection 62 projecting upward from the peripheral edge of the molding surface 61 is formed on the front surface side of the lower die 60. When the upper die 40 and the lower die 60 are brought close to each other in the vertical direction, the stepped portion 43 of the upper die 40 can enter the inside of the annular protruding portion 62 (see fig. 2).
A core adjustment surface (second mold side contact portion) 63 is formed on the back surface side of the lower mold 60. The aligning surface 63 is a part of a conical surface (outer surface of a cone) centered on the reference axis X, and has a diameter that decreases as it advances downward. The core surface 63 is a part of the same (apex angle equivalent) conical surface as the core surface 54 of the lower die base material 50.
The lower die 60 further has an outer peripheral surface 64 protruding upward from the peripheral edge of the cored surface 63. The outer peripheral surface 64 is a cylindrical surface centered on the reference axis X, and is connected to the annular protruding portion 62. The space between the aligning surface 63 and the outer peripheral surface 64 is formed in a gently curved surface shape.
The lower die 60 is positioned relative to the lower die base material 50 by bringing the aligning surface 63 into contact with the aligning surface 54. The aligning surface 54 and the aligning surface 63 are conical surfaces that are in surface contact with each other, and are in contact with each other with the central axes (a straight line passing through the apex in the height direction of the cone) thereof being aligned. Thus, the position of the lower die 60 in the up-down direction with respect to the lower die base material 50 is determined, and at the same time, the position of the lower die 60 in the radial direction with the reference axis X as the center is also determined. When the lower die 60 is positioned by the abutment of the aligning surface 54 and the aligning surface 63 in a state where the small diameter portion 52 of the lower die base material 50 is inserted into the cylindrical die 20 (fig. 1 and 2), the central axes of the lower die base material 50 and the lower die 60 coincide with the reference axis X. That is, the lower die 60 is properly aligned with respect to the cylindrical die 20 and the lower die base material 50, and the reference axis X passes through the center of the molding surface 61.
In a positioning state of the lower die 60 in which the aligning surface 54 and the aligning surface 63 are in contact with each other, a radial gap exists between the inner peripheral surface 56 and the outer peripheral surface 64. Thus, only the aligning surface 54 is positioned by directly abutting the lower die 60, and the positions other than the aligning surface 54 do not interfere with the positioning of the lower die 60.
The lower mold unit 12 is composed of a lower mold base material 50 made of non-glass (made of metal or ceramic) and a lower mold 60 made of glass, as in the upper mold unit 11. The lower mold 60 is a part of the lower mold unit 12 including a molding surface 61 for molding the glass lens 14, and the lower mold base 50 as the other part is formed of a metal or ceramic having heat resistance and impact resistance superior to those of glass. In particular, since the lower die base material 50 is a portion that slides against the cylindrical die 20 or receives a pressing force from the outside at the time of extrusion molding described later, it is effective to form it from a metal or ceramic having excellent mechanical strength, and the use of the lower die base material 50 helps to ensure the accuracy of the lower die unit 12.
The lower die 60 can be formed into a molding surface 61 and its surroundings, which are particularly small and simple in shape, and easy to manufacture. In more detail, the lower mold 60 has a simple cross-sectional shape similar to a concave lens in which the molding surface 61 and the aligning surface 45 are located on the front/rear surface. The wall thickness of the lower mold 60 in the up-down direction is about a fraction of the size of the entire lower mold unit 12 in the up-down direction. Therefore, the amount of glass constituting the lower mold 60 is reduced, and the cost at the time of manufacturing the lower mold 60 can be suppressed. In addition, in manufacturing the lower die 60, shrinkage of the glass due to cooling after molding is small, and accuracy control is easy.
The lower die base 50 and the lower die 60 are not fixed to each other by adhesion or the like, and are configured to position the lower die 60 by abutment of the centering surface 54 and the centering surface 63 which can be brought into close contact or separated. Therefore, even if the thermal expansion coefficients of the materials constituting the lower die base material 50 and the lower die 60 are different from each other, it is difficult to apply excessive stress to the boundary (contact) portion between them at the time of heating. That is, compared to a structure in which the lower die base material 50 and the lower die 60 are fixed to each other, the allowable range of the thermal expansion coefficients of the materials constituting the lower die base material 50 and the lower die 60 is wider, and the degree of freedom in selecting the materials is improved.
A heater, not shown, is provided outside the cylindrical mold 20. When the glass lens 14 is press-molded, the inside of the barrel mold 20 is heated by a heater up to a molding temperature at which the glass preform 13 (glass to be molded) is softened.
Although not shown, the upper mold 40 and the upper mold 60 may be manufactured by extrusion molding using a master mold (female mold). The master mold is separately prepared for manufacturing the upper mold 40 and the lower mold 60. These main molds are formed of metal, ceramic, or the like, and have reference molding surfaces as initial surfaces of the molding surfaces 41 and 61. The glass material for forming mold softened by heating (different from the glass to be formed for the glass lens 14, for glass satisfying each condition described later) is pressed by the reference forming surface of each main mold, and the upper mold 40 and the lower mold 60, which are transferred to the forming surface 41 and the forming surface 61, are formed.
The upper mold 40 and the lower mold 60 are respectively made of glass materials satisfying the following conditions.
(1) Young's modulus of 85Gpa or more.
(2) The glass transition temperature (Tg) is 650 ℃ or higher.
(3) The average thermal expansion coefficient (. Alpha.100-300) at 100℃to 300℃was 30X 10 -7/℃～80×10-7/. Degree.C.
Condition (1) relates to the rigidity of the upper mold 40 and the lower mold 60. If the upper mold 40 and the lower mold 60 bend during extrusion molding, the shape of the molding surfaces 41 and 61 cannot be maintained, and the molding accuracy of the glass lens 14 is affected. If the young's modulus is 85GPa or more, even if a predetermined pressing force is applied at the time of molding the glass lens 14, bending of the upper mold 40 and the lower mold 60 due to a load can be prevented, and molding can be performed without impairing the accuracy of the molding surfaces 41, 61.
Condition (2) relates to the influence of heating at the time of molding on the upper mold 40 and the lower mold 60. By setting the glass having a higher glass transition point than the glass to be molded, which is the material of the glass lens 14, as the material of the upper mold 40 and the lower mold 60, and setting the temperature lower than the glass transition point of the glass for the upper mold 40 and the lower mold 60 to the molding temperature, it is possible to soften only the glass to be molded without softening the upper mold 40 and the lower mold 60.
More specifically, the glass transition temperature of the glass as the material of the upper mold 40 and the lower mold 60 is Tg (a), and the glass transition temperature of the glass to be molded as the material of the glass lens 14 is Tg (B), and in this case, tg (a) -Tg (B) is preferably not less than 30 ℃. Further preferably, tg (A) -Tg (B) is not less than 50℃and still more preferably, tg (A) -Tg (B) is not less than 100 ℃.
For example, in the nitrate material for glass mold lenses produced by the applicant, the glass transition point is 612 ℃ at most (nitrate material name M-TAFD 305). Therefore, by satisfying the condition (2), the molding temperatures effective for various glass to be molded can be set while preventing thermal deformation of the upper mold 40 and the lower mold 60.
Condition (3) is a condition for properly controlling the difference in thermal expansion coefficient between the upper mold 40 and the lower mold 60 and the glass to be molded, thereby preventing adhesion or breakage of the glass to be molded and performing good molding. If the thermal expansion coefficients of the upper mold 40 and the lower mold 60 with respect to the glass to be molded are relatively large, breakage of the glass to be molded is liable to occur at the time of molding. In addition, if the difference in thermal expansion coefficients between the upper mold 40 and the lower mold 60 and the glass to be molded is too small, sticking of the glass to be molded to the upper mold 40 and the lower mold 60 is liable to occur.
More specifically, the average thermal expansion coefficient (100 to 300 ℃) of the glass as the material of the upper mold 40 and the lower mold 60 is α (a), and the average thermal expansion coefficient (100 to 300 ℃) of the glass to be molded as the material of the glass lens 14 is α (B), and in this case, α (a) - α (B) is preferably +20 to-120. More preferably, the ratio of α (A) - α (B) is +10 to-120, and still more preferably, the ratio of α (A) - α (B) is 0 to-100. In many cases, α (B) is about 70 to 90, and the effect of preventing breakage of the glass to be molded or sticking to the upper mold 40 and the lower mold 60 can be obtained by satisfying the condition (3) in the nitrate material for glass mold lenses.
In addition, the condition (3) also relates to the moldability when the upper die 40 and the lower die 60 are extrusion-molded by the main die. As an example, when a main mold is formed using silicon carbide (SiC) as a main material, the average thermal expansion coefficient (100 to 300 ℃) of silicon carbide is about 40×10 -7/°c, and therefore, the glass material for a molding die can be molded well by the condition (3), and the upper mold 40 and the lower mold 60 made of glass can be obtained. In particular, by satisfying the lower limit value of the condition (3), the thermal expansion coefficient of the master mold is not relatively excessively large, and cracking is less likely to occur when the upper mold 40 and the lower mold 60 are manufactured.
For example, a glass material for a molding die satisfying the conditions (1), (2) and (3) can be obtained according to the following raw material composition.
Expressed in mole%, the glass contains:
50-75% of SiO 2;
0-5% Al 2O3;
0-5% ZnO;
Na 2 O and K 2 O accounting for 3 to 15 percent;
MgO, caO, srO and BaO accounting for 14 to 35 percent in total;
ZrO2、TiO2、La2O3、Y2O3、Yb2O3、Ta2O5、Nb2O5 and HfO 2 in total of 2 to 9%,
Also, the molar ratio { (MgO+CaO)/(MgO+CaO+SrO+BaO) } is in the range of 0.85 to 1, and the molar ratio { Al 2O3/(MgO+CaO) } is in the range of 0 to 0.30.
The molding process of the glass lens 14 by using the glass lens molding die 10 having the above configuration will be described. First, in the component assembly in the preparation stage, the upper mold 40 and the upper mold base 30 are inserted into the internal space S of the cylindrical mold 20 in this order from above. The regulated surface 42 abuts against the upper die regulating surface 23 in the cylindrical die 20, thereby preventing the upper die 40 from falling down. The aligning surface 32 of the upper mold base 30 abuts against the aligning surface 45 of the upper mold 40, and the downward movement of the upper mold base 30 is also restricted. Specifically, the upper die unit 11 is in the state shown in fig. 3. The core surface 63 of the lower mold 60 is placed on the core surface 54 of the lower mold base material 50.
Since the upper die limiting surface 23 and the limited surface 42 are part of conical surfaces centered on the reference axis X, respectively, when the weight of the upper die 40 and the upper die base material 30 is applied, the limited surface 42 is pressed against the upper die limiting surface 23, and the downward movement of the upper die 40 is limited, and the position of the upper die 40 in the radial direction is also kept fixed. Therefore, the position of the upper die 40 in the cylindrical die 20 is stable, and the upper die 40 is less likely to shake in the cylindrical die 20 by an external force, so that the impact on the upper die 40 can be suppressed.
Next, as shown in fig. 1, the glass lens forming mold 10 is set to a ready state for extrusion forming. Specifically, the glass preform 13 is placed on the molding surface 61 of the lower mold 60, and the lower mold base material 50 is moved upward by the driving device 71, whereby the small diameter portion 52 is inserted into the cylindrical mold 20 from below. When the large diameter portion 51 abuts against the lower end of the cylindrical die 20, continued insertion of the small diameter portion 52 is restricted, and positions of the cylindrical die 20 and the lower die base material 50 in the up-down direction are determined.
When the small diameter portion 52 of the lower mold base material 50 and the lower mold 60 are inserted into the cylindrical mold 20, the glass preform 13 supported on the molding surface 61 is brought into contact with the molding surface 41 of the upper mold 40. Since the glass preform 13 has a shape having a larger thickness in the up-down direction than the glass lens 14 after molding, the upper mold 40 and the upper mold base 30 are pressed upward in the inner space S of the cylindrical mold 20 while sandwiching the glass preform 13 between the molding surface 41 and the molding surface 61. By this movement, the restricted surface 42 of the upper die 40 is separated upward from the upper die restricting surface 23 of the cylindrical die 20 (see fig. 1). The aligning surface 45 of the upper die 40 presses the aligning surface 32 of the upper die base 30 from below, and a part of the upper die base 30 protrudes upward from the upper end of the cylindrical die 20 (see fig. 1).
In the state where the preparation for extrusion molding is completed as shown in fig. 1, the aligning surface 32 of the upper die base material 30 is in contact with the aligning surface 45 of the upper die 40, and receives a force generated by the weight of the upper die base material 30. Therefore, the upper die 40 is cored by the cored surfaces 32 and 45 with respect to the upper die base 30, and the center axis of the upper die 40 coincides with the reference axis X. In this stage, the suction source 15 may be driven to suck the upper die 40 so as to strengthen the force of bringing the aligning surface 45 into contact with the aligning surface 32.
In the state of fig. 1, the aligning surface 54 of the lower mold base material 50 is in contact with the aligning surface 63 of the lower mold 60, and receives a force generated by the weight of the upper mold base material 30, the upper mold 40, the glass preform 13, and the lower mold 60. Therefore, the lower die 60 is cored by the cored surfaces 54 and 63 with respect to the lower die base material 50, and the center axis of the lower die 60 coincides with the reference axis X. In this stage, the suction source 17 may be driven to suck the lower die 60 so as to strengthen the force of bringing the aligning surface 63 into contact with the aligning surface 54.
Next, the inside of the barrel mold 20 is heated to a molding temperature at which the glass preform 13 can be molded, and in this state, as shown in fig. 2, the upper mold base material 30 is pressed downward from above by the driving device 70. Then, the upper mold 40 is pressed downward via the upper mold base 30, so that the heated glass preform 13 is deformed, and the interval between the molding surface 41 of the upper mold 40 and the molding surface 61 of the lower mold 60 is narrowed.
When the upper die 40 approaches the lower die 60, the void volume of the inner space S of the cylindrical die 20 decreases. At this time, the gas in the internal space S (gas generated during glass extrusion molding, etc.) is discharged to the outside through the through holes 25, 26, and the pressure in the cylindrical mold 20 is regulated. As shown in fig. 2, the through-hole 25 is formed on the side of the outer peripheral surface 46 of the upper die 40 that moves downward by pressing, and the through-hole 26 is formed on the side of the outer peripheral surface 64 of the lower die 60. Therefore, the gas can be reliably discharged from both the region in which the upper inner surface 21 of the upper die unit 11 is inserted and the region in which the lower inner surface 22 of the lower die unit 12 is inserted.
When the pressing is performed by the driving device 70, a compressive load acts between the upper die base material 30 and the lower die base material 50, and the pressing force in the up-down direction on each of the aligning surfaces 32 and 45 of the upper die unit 11 and the aligning surfaces 54 and 63 of the lower die unit 12 is increased. As the pressing force increases, the effect of positioning the upper die 40 and the lower die 60 increases, and the pressing process can be reliably and restrictively performed without shifting the positions of the upper die 40 and the lower die 60.
The driving device 70 presses the upper die base material 30 until the upper end surface of the upper die base material 30 and the upper end surface of the cylindrical die 20 are flush (fig. 2). For example, the driving device 70 preferably includes a stopper (not shown) that abuts against the upper end surface of the cylindrical die 20 and is restricted from moving downward. When the upper mold base 30 is pressed to the position of fig. 2, the step portion 43 of the upper mold 40 slightly enters the inside of the annular protruding portion 62 of the lower mold 60, and the glass lens 14 is formed in the space surrounded by the molding surface 41, the molding surface 61, and the annular protruding portion 62. At this time, a gap exists between the restricted surface 42 of the upper die 40 and the upper die restricting surface 23 of the cylindrical die 20, and the upper die 40 is not directly restricted by the position of the cylindrical die 20.
After the extrusion process shown in fig. 2 is completed, the temperature in the barrel mold 20 is lowered to a predetermined temperature lower than the molding temperature, and the glass lens 14 is cured. Next, as shown in fig. 3, the lower die base 50 is moved downward by the driving device 71, and the upper die 40 and the lower die 60 are separated in the vertical direction. At this time, the suction source 17 is driven to hold the lower mold 60 on the aligning surface 54 side of the lower mold base material 50 by suction, so that the lower mold 60 can be reliably separated downward without bringing the lower mold 60 into a state of being attached to the upper mold 40 together with the glass lens 14. After the separation of the upper mold 40 from the lower mold 60 is completed, the glass lens 14 is removed from the lower mold 60. Thereby, the glass lens 14 having the molding surfaces 41 and 61 of the upper mold 40 and the lower mold 60 transferred to the lens surfaces 14a and 14b is completed.
As shown in fig. 3, when the lower die 60 moves downward, the upper die 40 is not supported by the lower die unit 12 from below. However, the restricted surface 42 abuts against the upper die restricting surface 23 of the cylindrical die 20, so that the downward movement of the upper die 40 in the cylindrical die 20 is restricted, and the upper die 40 does not fall off, and the upper die unit 11 can be maintained. Therefore, although the upper mold 40 is not fixed to the upper mold base 30, the upper mold unit 11 can be handled in the same manner as in the case of the integrally structured molding mold, and excellent productivity can be obtained.
When the upper die 40 and the lower die 60 are separated as shown in fig. 3, the suction source 15 is preferably driven to suction and hold the upper die 40 on the aligning surface 32 side of the upper die base 30. As described above, since the upper mold 40 is restricted from moving downward by the upper mold restricting surface 23, the upper mold 40 is not released downward with the lower mold 60 while being attached thereto, but is held by suction on the upper mold base 30 side, and therefore, the stability of the upper mold 40 is improved, and the glass lens 14 is easily removed from the molding surface 41.
As described above, in the glass lens molding die 10 of the present embodiment, the upper die unit 11 and the lower die unit 12 are configured by combining the upper die 40 and the lower die 60 made of glass and the upper die base 30 or the lower die base 50 made of a non-glass material such as metal or ceramic.
The portions of the upper die unit 11 and the lower die unit 12 which are positioned directly with respect to the cylindrical die 20 and receive the driving load generated by the driving devices 70 and 71 are each composed of the upper die base material 30 and the lower die base material 50 which are excellent in strength, impact resistance, heat resistance, and the like. Therefore, even if the molding of the glass lens 14 is repeated, an accuracy error is less likely to occur, and high durability can be obtained. On the other hand, the portions having the molding surfaces 41 and 61 and directly involved in the formation of the glass lens 14 can be mass-produced at low cost by using the upper mold 40 and the lower mold 60 made of glass.
The upper mold base 30 and the upper mold 40 are not fixed to each other, and the tapered centering surfaces 32 and 45 positioned (centering) according to the load in the up-down direction are brought into contact with each other. The lower die base material 50 and the lower die 60 are not fixed to each other in the same manner, and the tapered alignment surfaces 54 and 63 positioned (aligned) according to the load in the up-down direction are brought into contact with each other. Therefore, the load on heating due to the difference in thermal expansion coefficient between the upper die base material 30 and the upper die 40 and between the lower die base material 50 and the lower die 60 is reduced, and the durability of each of the upper die unit 11 and the lower die unit 12 is also excellent. Further, since the allowable range of the difference in the thermal expansion coefficients of the upper die base material 30 and the lower die base material 50 with respect to the upper die 40 and the lower die 60 is wide, the degree of freedom in selecting the materials is high.
Further, the upper die 40 used separately from the upper die base 30 is limited in the amount of movement in the direction in which the aligning surface 32 and the aligning surface 45 are separated by the upper die limiting surface 23 provided on the cylindrical die 20. Thus, even in a state where the lower die unit 12 is separated, the upper die 40 can be held on the upper die unit 11 side, and the next molding process can be performed as it is. In addition, although the upper mold 40 and the lower mold 60 are not fixed, the operation using the driving device 70 and the driving device 71 can be as simple as the case of using a molding mold integrally formed, and therefore, the molding process is efficient and requires no complicated control. In addition, the abutment of the restricted surface 42 against the upper die restricting surface 23 (see fig. 2) does not occur during the operation of press molding the glass lens 14, and molding accuracy is not affected.
As described above, the glass lens forming mold 10 of the present embodiment is excellent in productivity, durability, high precision, and practicality. However, the present invention is not limited to the above-described embodiments, and various modifications can be made within the gist of the present invention.
For example, in the above embodiment, both the upper die unit 11 and the lower die unit 12 are configured by a combination of the upper die 40 and the lower die 60 made of glass, and the upper die base 30 and the lower die base 50 made of metal or ceramic. In contrast, a molding die having an integral structure may be selected for a portion corresponding to the lower die unit 12 without being divided into two parts. In this case, the molding die of the lower die unit 12 may be made of glass or non-glass such as metal or ceramic instead of the molding die of the lower die unit.
In the above embodiment, the upper inner surface 21 of the cylindrical die 20, the slide guide surface 31 of the upper die base 30, the lower inner surface 22 of the cylindrical die 20, and the slide guide surface 53 of the lower die base 50 are formed as cylindrical surfaces centered on the reference axis X. However, the upper inner surface 21 and the slide guide surface 31, and the lower inner surface 22 and the slide guide surface 53 may be formed in various shapes by relatively moving the upper die base 30 and the lower die base 50 in the up-down direction without tilting or rocking with respect to the cylindrical die 20. For example, a plane having a polygonal or elliptical cross-sectional shape perpendicular to the reference axis X may be used.
When the upper die unit 11 is separated from the lower die unit 12, the regulating portion (regulating surface) for regulating the downward movement amount of the upper die 40 is preferably a conical surface like the above-described die regulating surface 23. As described above, the structure in which the conical restricted surface 42 is abutted against the conical upper die restricting surface 23 is excellent in the stability of the upper die 40 at the abutment, and the upper die 40 is less likely to be damaged by accidental movement and collision with the surroundings. Further, since the upper die 40 is supported in the entire circumferential direction, it is difficult to apply a local load to the upper die 40.
However, a limiting surface other than the upper die limiting surface 23 may be selected in view of the downward movement limitation of the upper die 40. As an example, a flat (stepped) restricting surface perpendicular to the reference axis X may be provided on the cylindrical mold 20.
Instead of the above-described die limiting surface 23 (projection 24), a continuous configuration may be selected in which the limiting portion (limiting surface) is partially provided in the circumferential direction, and the limiting portion is continuous in the circumferential direction around the reference axis X. For example, if the length in the circumferential direction is a certain or more, it is divided into two, and if the length in the circumferential direction is short, it is divided into three (or four) or more, and a portion corresponding to the protruding portion 24 may be intermittently provided.
In the above embodiment, the conical cored surfaces 32, 45 are provided in the upper die unit 11 on both the upper die base 30 and the upper die 40, and the conical cored surfaces 54, 63 are provided in the lower die unit 12 on both the lower die base 50 and the lower die 60. As a modification, a conical aligning surface may be provided only on one side of the upper die base 30 and the upper die 40, or only on one side of the lower die base 50 and the lower die 60, and a contact portion having a shape other than the conical surface may be provided on the other side. The contact portion in this case may be any shape as long as the radial position is determined when pressed against the conical aligning surface, and various shapes can be selected.
In the above embodiment, the inner diameter of the upper inner surface 21 of the cylindrical mold 20 is set to be larger than the inner diameter of the lower inner surface 22, but a configuration may be adopted in which the inner diameter of the lower inner surface 22 is larger than the inner diameter of the upper inner surface 21, or a configuration in which the inner diameters of the upper inner surface 21 and the lower inner surface 22 are equal.
In the above embodiment, when the pressing operation for bringing the upper die 10 and the lower die 60 close to each other is performed (fig. 2), the upper die base material 30 is pressed downward by the driving device 70, and when the upper die 40 and the lower die 60 are separated from each other (fig. 3), the lower die base material 50 is moved downward by the driving device 71. In a different manner, the operation of the molding die may be performed.
As an example of the different operation of the molding die, when the extrusion operation is performed from the preparation state of fig. 1, the upper die base material 30 may be fixed first, and then the lower die base material 50 and the lower die 60 may be moved upward.
Further, as a different example, when the upper die 40 and the lower die 60 are separated after the extrusion molding of fig. 2 is completed, the upper die 40 may be moved upward. In this case, a first method of applying an upward moving force to the cylindrical mold 20 and a second method of applying an upward moving force to the upper mold base 30 may be selected.
In the first embodiment in which the cylindrical die 20 is moved upward, the upper die regulating surface 23 abuts against the regulated surface 42, and thereby upward movement force is transmitted to the upper die 40, and upward movement force is transmitted from the upper die 40 to the upper die base 30. At this time, since the upper die regulating surface 23 and the regulated surface 42 have conical shapes centered on the reference axis X, the upper die 40 does not shift radially and moves upward. As a result, the glass lens 14 can be separated upward from the molding surface 61 of the lower mold 60 without applying an unnecessary load.
In the second embodiment of applying an upward movement force to the upper mold base material 30, the suction source 15 is driven to suction and hold the upper mold 40 on the aligning surface 32 side of the upper mold base material 30. This prevents the upper mold 40 from adhering to the lower mold 60 together with the glass lens 14, and can reliably separate the upper mold 40 upward.
The lower mold 60 of the above embodiment is of a type in which the outer peripheral surface of the edge portion 14c is formed by the annular protruding portion 62, and the basic shape of the glass lens 14 is completed by one-time extrusion molding. Alternatively, a molding die may be selected which does not surround the outer peripheral surface of the edge portion 14c (the lower die 60 does not include the annular protruding portion 62). In this case, after the extrusion molding, a process is performed to remove the excess wall portion protruding from the peripheral edge of the glass lens 14.
(Industrial applicability)
According to the present invention, a glass lens molding die excellent in productivity, durability, high precision, and practicality can be obtained, and is particularly useful for a manufacturing apparatus for efficiently manufacturing a large number of glass lenses.
Claims (6)
1. A glass lens molding die for extrusion molding a glass lens, comprising:
A cylindrical mold having an inner space extending in a mold moving direction;
a mold base material made of metal or ceramic, inserted into the inner space of the cylindrical mold, having an outer surface slidably supported on an inner surface of the inner space of the cylindrical mold in the mold moving direction, and having a base material side contact portion at one end in the mold moving direction;
A glass molding die made of glass having a higher glass transition temperature than glass to be molded, which is a material of the glass lens, and having a molding surface forming one lens surface of the glass lens and a die-side contact portion which is oriented to the opposite side of the molding surface in the die moving direction and is capable of approaching or separating from the base-side contact portion;
An opposing mold having a second molding surface and being movable relative to the glass molding mold in the mold movement direction, the second molding surface opposing the molding surface to form the other lens surface of the glass lens,
A gap is provided between an inner surface of the inner space of the cylindrical mold and an outer peripheral surface of the glass forming mold,
At least one of the substrate-side contact portion and the mold-side contact portion has a centering surface which is a part of a conical surface centered on an axis extending in the mold moving direction, and the glass-forming mold is held in a fixed position with respect to the mold substrate in the mold moving direction and in a direction perpendicular to the mold moving direction by contact of the substrate-side contact portion with the mold-side contact portion.
2. The glass lens forming mold according to claim 1, wherein,
The mold base material includes a suction hole for allowing the suction force held by the aligning surface to act on the glass molding mold.
3. The glass lens forming mold according to claim 2, wherein,
The substrate side abutting part is provided with the aligning surface,
The die base material is provided with a concave part comprising the aligning surface and the bottom surface,
The suction hole opens to the bottom surface of the recess.
4. A glass lens forming mold according to any of claims 1 to 3, wherein,
The opposing mold includes:
a second mold base material made of metal or ceramic, inserted into the inner space of the cylindrical mold, having an outer surface slidably supported on an inner surface of the inner space of the cylindrical mold in the mold moving direction, and having a second base material side contact portion at one end in the mold moving direction;
A second glass molding die made of glass having a higher glass transition temperature than glass to be molded as a material of the glass lens, the second glass molding die having the second molding surface and a second die-side contact portion which is oriented to the opposite side of the second molding surface in the die moving direction and is capable of approaching or separating from the second base-side contact portion,
A gap is provided between an inner surface of the inner space of the cylindrical mold and an outer peripheral surface of the second glass forming mold,
At least one of the second base material side abutting portion and the second mold side abutting portion has a core adjusting surface which is a part of a conical surface centering on the axis, and the second glass forming mold is held at a fixed position with respect to the second mold base material in the mold moving direction and in a direction perpendicular to the mold moving direction by abutting of the second base material side abutting portion and the second mold side abutting portion.
5. The glass lens forming mold according to claim 4, wherein,
The second mold base material includes a suction hole for allowing the suction force held by the aligning surface to act on the second glass molding mold.
6. The glass lens forming mold according to claim 5, wherein,
The second substrate side abutting part is provided with the aligning surface,
The second die base material is provided with a concave part concavely arranged from the central part of the aligning surface,
The suction hole opens to a bottom surface of the recess.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310012251.0A CN115806380B (en) | 2018-06-04 | 2019-06-03 | Glass lens forming die |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018106637A JP7066533B2 (en) | 2018-06-04 | 2018-06-04 | Glass lens molding mold |
| JP2018-106637 | 2018-06-04 | ||
| PCT/JP2019/022039 WO2019235443A1 (en) | 2018-06-04 | 2019-06-03 | Mold for molding glass lens |
| CN201980035739.7A CN112218832B (en) | 2018-06-04 | 2019-06-03 | Glass lens forming mold |
| CN202310012251.0A CN115806380B (en) | 2018-06-04 | 2019-06-03 | Glass lens forming die |
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| CN201980035739.7A Division CN112218832B (en) | 2018-06-04 | 2019-06-03 | Glass lens forming mold |
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| CN115806380B true CN115806380B (en) | 2024-11-15 |
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| US20220048803A1 (en) * | 2020-08-13 | 2022-02-17 | Lightpath Technologies, Inc. | Systems and methods for molding chalcogenide glass into a near-net shaped part |
| CN115231807B (en) * | 2022-08-02 | 2024-06-07 | 芜湖长信科技股份有限公司 | Glass forming die |
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| JP2000264654A (en) * | 1999-03-17 | 2000-09-26 | Asahi Optical Co Ltd | Mold forming mold, its production and apparatus for producing the same |
| JP4718864B2 (en) * | 2005-03-02 | 2011-07-06 | Ｈｏｙａ株式会社 | Press mold and press molding method |
| JP4780982B2 (en) * | 2005-03-14 | 2011-09-28 | Ｈｏｙａ株式会社 | Mold press molding apparatus and optical element manufacturing method |
| JP2007223875A (en) * | 2006-02-27 | 2007-09-06 | Matsushita Electric Ind Co Ltd | Forming mold, mold assembly with it and its producing method |
| JP2007302502A (en) * | 2006-05-10 | 2007-11-22 | Alps Electric Co Ltd | Method for producing optical lens, lens material used for the same, and method for producing the lens material |
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| JP2616964B2 (en) * | 1988-06-21 | 1997-06-04 | ホーヤ株式会社 | Glass press mold |
| CN101304953A (en) * | 2005-11-14 | 2008-11-12 | 旭硝子株式会社 | Method and apparatus for molding optical element |
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| Publication number | Publication date |
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| CN112218832B (en) | 2023-01-31 |
| WO2019235443A1 (en) | 2019-12-12 |
| CN112218832A (en) | 2021-01-12 |
| JP7066533B2 (en) | 2022-05-13 |
| CN115806380A (en) | 2023-03-17 |
| JP2019210176A (en) | 2019-12-12 |
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