JP2000264654A - Mold forming mold, its production and apparatus for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold forming mold excellent in strength with a slight eccentricity, a method for producing the mold and an apparatus for producing the mold. SOLUTION: This mold forming mold is produced by pressing a base member 18 in the direction of holding members 16 and 17 with a transfer base mold 15 having a transfer molding surface 15b in order to provide a lens molding surface of a prescribed shape using the base member 18 comprising a glass softening at a high temperature and the holding members 16 and 17 holding the base member 18 without causing eccentricity and compounding and integrating the base member 18 with the holding members 16 and 17 while forming the lens molding surface in the base member 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for manufacturing a lens, a method for manufacturing the same, and a manufacturing apparatus.

[0002]

2. Description of the Related Art In recent years, an objective lens (imaging lens) of an optical device has been required to improve optical performance while reducing the number of lens components (in particular, to correct distortion).
Aspheric lenses tend to be used.

[0003] Such an aspheric lens is often manufactured by glass molding in order to improve the accuracy while facilitating the manufacturing process and realize low cost. This glass molding is a method in which a glass preform is crushed by a cemented metal mold to form a lens shape, so a mold having a lens molding surface of a predetermined shape must be prepared in advance. Must.

[0004] Usually, this molding die is manufactured by grinding a hard metal with a diamond grindstone. However, when the desired lens surface is a convex surface, the lens molding surface of the mold needs to be processed into a concave surface that is relatively difficult to process, and when the desired lens is a micro lens, the concave surface is used. Processing becomes more difficult.

[0005] As described above, a technique has been proposed in which, when ordinary grinding is difficult, a forming die is formed by using glass instead of a hard metal. That is, a transfer base mold having a transfer molding surface of a predetermined shape for obtaining a lens molding surface is prepared in advance, and glass having a pressing temperature higher than the pressing temperature of the glass to be molded to be processed into a lens is used as the base of the molding die. The base material of the molding die is set on the transfer molding surface of the transfer substrate die, and the base material of the molding die is press-molded while being thermally softened to obtain a molding die base.

[0006] The base of the mold thus obtained has a surface on which the transfer molding surface of the transfer substrate is reversely transferred. By further cold-working the base, a lens forming surface for obtaining a lens surface of a predetermined shape, a flange portion for fixing the forming die during the glass molding operation, and a sliding guide for guiding a sliding operation during the glass molding operation. A moving part was produced to complete a desired mold.

[0007]

However, the glass mold has the following problems. That is, since it is made of glass, it is easily damaged by impact. Further, at the time of the glass molding operation in the lens manufacturing process, the brim portion and the sliding portion of the mold come into contact with the hard metal material, and therefore receive a particularly large force. Therefore, if these collars and sliding parts are made of glass, the parts concerned are particularly easily broken.

[0008] Further, when the obtained mold base is combined with other members to form a mold, unless the combination is performed with high precision, the lens manufactured using the mold will be eccentric. Will occur.

The present invention has been made in view of such a problem in molding a lens, and an object of the present invention is to provide a mold having excellent strength and less eccentricity, a method of manufacturing the same, and a manufacturing apparatus.

[0010]

The present invention has the following features to attain the object mentioned above. That is, claim 1
The invention described is a molding die used when molding a lens having a lens surface of a predetermined shape, wherein a base member having a lens molding surface having a predetermined shape for obtaining the lens surface is formed on an end surface. And an accommodation hole for accommodating the base member at one end, fixing means for fixing the molding die at the other end, and a sliding portion for guiding a sliding operation when molding the lens on a side surface. And a columnar holding member.

With this configuration, a material suitable for forming a lens molding surface can be used as a base material of the base member, and a material for fixing and fixing the lens during molding can be used as the material of the holding member. A material that can withstand the sliding operation can be used. In addition, the lens surface of the lens manufactured by this mold may be a convex surface or a concave surface, and may be an aspheric surface or a spherical surface. The lens may be a glass lens or a plastic lens.

According to a second aspect of the present invention, in the first aspect, the base member is made of a material having a softening point higher than a softening point of the optical material for the lens, and the holding member is made of a material having a softening point higher than that of the base member. Is also made of a high-temperature-resistant and hard material.

According to a third aspect of the present invention, in the first or second aspect, the holding member has a sliding portion having a cylindrical surface, and the fixing means projects annularly from the sliding portion. It is specified by being configured as a tobacco section. The sliding portion is not limited to the cylindrical surface, and may have a side surface of a prism, or may have an elliptical surface whose cross section orthogonal to the axial direction. Further, the fixing means is not limited to the brim portion, and may have a shape in which it is annularly indented from the sliding portion.

According to a fourth aspect of the present invention, in the third aspect, the holding member includes a holding surface which is rotationally symmetric with respect to a center axis of a sliding portion of the holding member on an inner surface of the receiving hole, This is specified by positioning and holding the base member on the holding surface.

According to a fifth aspect of the present invention, in the fourth aspect, the holding surface has a shape in which a side surface of a cone or a truncated cone is inverted.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the holding member has a shape in which the inner surface of the receiving hole is narrowed, and the holding portion holds and fixes the base member. Is provided.

According to a seventh aspect of the present invention, in the sixth aspect, the holding portion of the holding member is specified to be rotationally symmetric with respect to a center axis of a sliding portion of the holding member.

According to an eighth aspect of the present invention, in the sixth or seventh aspect, the holding member comprises a member on the side where the holding hole of the holding member is opened and a member on the back side of the holding hole. It is specified by being detachably engaged with each other, and by providing the grip portion on a member on the side where the receiving hole is opened.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a mold according to any one of the first to eighth aspects, wherein the base member and the holding member are compositely integrated by a molding method. It is characterized by being manufactured.

According to a tenth aspect of the present invention, in the ninth aspect, the lens molding surface of the base member is formed simultaneously with the composite integral molding of the base member and the holding member by the molding method. , Specified.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect, a transfer base mold having a transfer molding surface of a predetermined shape for obtaining the lens molding surface is prepared in advance, and the transfer base mold is transferred. The molding surface is specified by reversely transferring the molding surface to the base member and forming the lens molding surface on the base member.

The invention according to claim 12 is the invention according to claims 9 to 11
In any one of the above, the method is specified by further forming a release film on the lens molding surface formed on the base member. A release film may be formed on the transfer molding surface of the transfer substrate die.

According to a thirteenth aspect of the present invention, there is provided an apparatus for manufacturing a mold for use in molding a lens having a lens surface having a predetermined shape. 4. A transfer base mold having a transfer molding surface of a shape, a base member softened under heating, and a transfer base mold.
8. A holding member according to any one of claims 1 to 8, a heating device for heating the base member and the holding member, and a pressing mechanism for pressing a transfer molding surface of the transfer base die onto the base member.

According to a fourteenth aspect of the present invention, in the thirteenth aspect, a cylindrical body die for inscribing the sliding portion of the holding member is further provided, and the transfer base surface is formed such that the transfer molding surface has a front end. It is specified by having a columnar portion formed on the surface and slidably inscribed with the body mold.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment This embodiment shows a method for forming a mold (including a molding surface) from high-transition glass.

FIG. 1 is a schematic (partially sectional) schematic view showing a main part of a manufacturing apparatus P for forming a mold. As shown in FIG. 1, the manufacturing apparatus P includes a vacuum chamber 5, a mechanism built in the vacuum chamber 5,
The mechanism inside the vacuum chamber 5 is divided into a device for operating the mechanism inside from outside.

The vacuum chamber 5 is formed of a closed cylindrical glass container set with its central axis directed vertically, and is opened / closed by an opening / closing port (not shown), and is evacuated through a suction pipe. It is exhausted by the device 6.

At the center of the bottom surface inside the vacuum chamber 5, a lower press stage 4 made of a cylindrical metal block is fixed. A weight control system (control circuit) 13 is provided at the center of the upper surface outside the vacuum chamber 5.
The hydraulic device 8 controlled by the control is fixed. The hydraulic device 8 drives the piston 7 that passes through the zenith 5a of the vacuum chamber 5 along the central axis of the vacuum chamber 5 to advance and retreat.
A pressing force toward the lower press stage 4 is applied.

An upper press stage 9 made of a cylindrical metal block having the same diameter as the lower press stage 4 is attached to the tip of the piston 7 in the vacuum chamber 5. Between the lower press stage 4 and the upper press stage 9, a set die S described later is sandwiched. That is, the lower press stage 4 and the weight control system 1
3, the hydraulic device 8 and the upper press stage 9 constitute a pressing mechanism. The end faces of the press stages 4 and 9 facing each other are a pair of opposing pressing surfaces that sandwich the set mold S from both ends and approach each other.

In the vacuum chamber 5, the moving area of the lower press stage 4 and the upper press stage 9
It is surrounded by a heater 3 wound in a cylindrical shape.
The heater 3 generates heat in accordance with the electric power supplied by the power supply device 1 and heats the set mold S. The thermocouple 10 for detecting the temperature of the set S is in contact with the surface of the set S, and the output of the thermocouple 10 is supplied to a temperature control system (circuit) 2. The temperature control system (circuit) 2 uses the output of the thermocouple 10 as feedback information, and determines the magnitude of power supplied from the power supply device 1 to the heater 3 so that the temperature of the set mold S maintains a predetermined temperature. Automatic control. That is, the heater 3, the power supply device 1, the thermocouple 10, and the temperature control system 2 correspond to a heating device.

Next, the structure of the set mold S sandwiched between the upper and lower press stages 9 and 4 in the vacuum chamber 5 will be described in detail with reference to FIG. FIG.
It is an enlarged sectional view of this set type S. As shown in FIG. 2, the set mold S has a cylindrical body mold 14, a transfer base mold 15 inserted into a sliding hole 14a of the body mold 14 from an upper end side opening thereof, and a transfer mold 15 having the same slide hole 14a. The holding members 16, 17 inserted from the lower end side openings, the base member 18 sandwiched between the transfer base die 15 and the holding members 16, 17 in the sliding hole 14a, and the outer periphery of the body die 14 are covered. It is composed of a cylindrical spacer 19.

Of these, the body mold 14 and the transfer base mold 15 are respectively made of a cemented carbide material (average expansion coefficient 50 × 1).
0 ^-7 : 35 to 680 ° C.). The body die 14 functions to guide the transfer base die 15 in the sliding direction of the upper press stage 4. In the example shown here, the body mold 14 has an inner diameter of 20.0 mm.
It is machined so as to be 03 ± 0.001 mm, and the sliding hole 14a is machined to a surface roughness necessary for sliding.

The transfer base die 15 functions as a matrix for embossing the base member 18. Therefore, the transfer base die 15 has a cylindrical portion 15a whose diameter is slightly smaller than the inner diameter of the body die 14 (φ20.000 ± 0.001 mm) and whose outer peripheral surface is finished to a surface roughness necessary for sliding. The distal end surface of the cylindrical portion 15a is processed as a transfer molding surface 15b protruding in an aspherical shape (or a spherical shape) in the distal end direction. That is, the shape of the transfer molding surface 15b is mirror-finished so as to have a predetermined shape for obtaining a lens molding surface 18a of a mold 91 for manufacturing a lens described later.

Further, the cylindrical portion 15 of the transfer substrate die 15
A brim-shaped edge portion 15c is formed at the upper end of a, and the outer diameter of the edge portion 15c is formed to be larger than the inner diameter of the body die 14 and smaller than the outer diameter of the body die 14.

Next, each of the holding members 16 and 17 is made of a cemented carbide material (average expansion coefficient 60 × 10
^-7 : 35 ~ 680 ℃) by grinding the block
Is formed. The first holding member 16 includes a portion having a cylindrical boundary surface (sliding portion 16a) that can be fitted into the sliding hole 14a of the body die 14, and a flange portion (radially projecting from the lower end of the cylinder). Fixing means) 16b.

The outer diameter of the sliding portion 16a is slightly smaller than the inner diameter of the sliding hole 14a of the body mold 14 (φ19.988 ± 0.001).
mm), and the outer diameter of the collar portion 16b is
The sliding hole 14a is formed to have a diameter larger than the inner diameter and smaller than the outer diameter of the sliding hole 14a. Note that the outer peripheral surface of the sliding portion 16a is processed to have a surface roughness required for sliding.

The inner side of the sliding portion 16a of the holding member 16 has a holding surface 16c having a shape (slivery shape) tapered from the upper opening end.
And downward from a position coinciding with the lower end of the holding surface 16c,
And a portion that expands in a tapered shape. That is, the sliding portion 1
The space formed inside 6a narrows downward from its upper opening, narrows most at the lower end of the holding surface 16c, and flanges downward from the narrowest part (gripping portion 16d). It expands to a height slightly higher than the portion 16b. Note that the holding surface 16c has a center axis
Is machined with high precision so as to coincide with the central axis of, and to have a shape rotationally symmetric with respect to the coincident central axis (in this case, a shape in which the side surface of the truncated cone is inverted).

Further, from the lower end surface of the holding member 16 to a height slightly above the flange 16b, there is formed a fitting hole 16e formed in a cylindrical shape having a diameter smaller than the outer diameter of the sliding portion 16a. Note that the diameter of the fitting hole 16e is
The diameter is larger than the most enlarged portion (the lower end portion of the tapered portion) of the lower tapered portion.

The second holding member 17 combined with the first holding member 16 includes a large-diameter portion 17a having a columnar shape substantially the same diameter as the fitting hole 16e of the first holding member 16, A substantially cylindrical small-diameter portion 17b protruding above the large-diameter portion 17a
And The upper end surface of the small diameter portion 17b is substantially flat, but is formed so that its central portion is slightly raised. The large-diameter portion 17a of the second holding member 17 is fitted into the fitting hole 16e of the first holding member 16 by the two holding members 16,
17 are fitted so that the lower end surfaces thereof coincide with each other, and in this state, the second holding member 17 has its small-diameter portion 17b distal end surface located below the grip portion 16d of the first holding member 16.
It is arranged so as not to contact the first holding member 16.

Further, as described above, the holding members 16, 17
The holding surface 16c, the gripping portion 16d, the tapered portion extending downward from the gripping portion 16d, and the substantially flat portion (the upper end surface of the small diameter portion 17b) disposed below the gripping portion 16d, A space (accommodation hole) for accommodating the member 18 is formed. Although the accommodation hole may be formed by a single member, as described above, the two members (the holding members 16 and
If 17) is combined to form the accommodation hole, processing becomes easy.

The base member 18 is made of a high transition point glass, ie,
It is composed of OHARA optical glass SK10 (transition point 665 ° C., bending point 686 ° C.). The base member 18 has an upper portion having a tapered shape so as to correspond to the holding surface 16c of the holding member 16, and a cylindrical lower portion having substantially the same diameter as the most narrowed circumferential portion of the grip portion 16d. And are integrally formed into a preform. In addition,
The upper end surface of the base member 18 is not flat but processed into a shape that is approximately approximated to the shape of the lens surface.

The spacer 19 is made of a SUS material, and its inner diameter is substantially the same as the outer diameter of the body mold 14. A body mold 14 is fitted into the spacer 19, and the lower end of the body mold 14 is fitted with both holding members 16, 17 in a combined state. The holding member 16 is arranged such that the lower end surface of the collar portion 16b is on the same plane as the lower end surface of the spacer 19, and the lower end surface of the body mold 14 is in contact with the upper end surface of the collar portion 16b of the holding member 16. And so on. And, in the holding portion 16d of the holding member 16,
The lower portion of the base member 18 is fitted, and the lower end surface of the base member 18 is in contact with the upper end surface of the holding member 17. In addition, body type 1
4, the cylindrical portion 15a of the transfer substrate die 15
Are fitted so that the transfer molding surface 15b contacts the upper end surface of the base member 18. In this state, the lower end of the edge 15 c of the transfer base die 15 is located slightly above the upper end of the trunk die 14 without contacting the upper end of the trunk die 14.

The sum of the length from the upper end surface of the transfer substrate die 15 to the lower end of the outer peripheral surface of the cylindrical portion 15a and the length from the lower end surface of the holding member 16 to the upper end of the sliding portion 16a is determined by the axis of the spacer 19. It is less than the length in the direction. Further, the holding surface 16c of the holding member 16 has a tapered shape with a deeper inclination than a shape (lens surface shape) obtained by inverting the transfer molding surface 15b of the transfer base die 15.

The length from the upper end surface of the transfer base die 15 to the center of the lower end surface thereof, the length from the center of the upper end surface of the base member 18 to the lower end surface thereof, and the distance from the center of the upper end surface of the holding member 17 to the lower portion thereof. The difference between the sum of the length to the end face and the axial length of the spacer 19 is: the length from the plane including the lower end face of the flange portion 15c of the transfer base die 15 to the center of the transfer molding surface 15b, The sum of the length from the center of the end face to the lower end face thereof, and the length from the center of the upper end face of the holding member 17 to the plane including the upper end face of the flange 16b of the holding member 16;
The difference from the axial length of

That is, in the set die S shown in FIG. 2, the upper end of the transfer base die 15 projects slightly above the upper end of the spacer 19, and the height of this protrusion is equal to the lower end of the edge 15c of the transfer base die 15. It is set smaller than the gap with the upper end of the trunk mold 14. Then, the base member 18 is pushed downward by the transfer base die 15 by the displacement from the upper end of the spacer 19 to the upper end of the transfer base die 15.

The procedure for manufacturing the mold 91 using the manufacturing apparatus P incorporating the set mold S configured as described above will be described below. First, an operator produces each part of the set die S, that is, the transfer base die 15, the trunk die 14, the spacer 19, and the holding members 16, 17 by using various processing machines such as a lathe and a curve generator. At this time, the transfer molding surface 15b of the transfer substrate die is mirror-finished with high precision so as to have a predetermined shape such that a target lens molding surface is obtained.

Then, the worker holds the obtained holding member 17.
Is incorporated into the holding member 16 such that the large diameter portion 17a fits into the fitting hole 16e of the holding member 16 with the small diameter portion 17b facing upward.
Are arranged such that the lower end surfaces of the both ride on the same surface. Further, the worker fits the base member 18 with the lower part thereof fitted into the holding portion 16d of the holding member 16 and the lower end face of the holding member 1.
7 is mounted on the holding members 16 and 17 such that the small diameter portion 17b is in contact with the upper end surface of the small diameter portion 17b and the upper portion thereof is substantially in contact with the holding surface 16c of the holding member 16.

Next, the operator operates the base member 18 in this manner.
The holding members 16, 17 in which are embedded are inserted through the lower opening of the body die 14, and the sliding portion 16 a of the holding member 16 is
Of the holding member 16
The upper end of the flange 16b is brought into contact with the lower end of the shell 14.

Further, the operator inserts the transfer base mold 15 from the upper opening of the barrel mold 14 with the cylindrical portion 15a inscribed in the sliding hole 14a of the barrel mold 14 and the transfer molding surface 15
Insert so that b contacts the upper end surface of the base member 18.
Then, the worker sets the transfer base die 15 and the base member 1
8 and a barrel mold 14 in which holding members 16 and 17 are incorporated.
Is inserted into the spacer such that the outer peripheral surface of the body mold 14 contacts the inner peripheral surface of the spacer 19, and the lower end surfaces of the spacer 19 and the lower end surfaces of the holding members 16 and 17 are on the same surface. To complete the set mold S. In this completed state, the upper end of the transfer substrate die 15 is
9 protrudes from the upper end by a predetermined displacement.

Next, the operator incorporates the set mold S obtained as described above into the manufacturing apparatus P. That is, the manufacturing apparatus P
The vacuum chamber 5 is opened and the weight control system 13 is opened.
Is operated, the piston 7 is retracted by the hydraulic device 8, and the set mold S is inserted between the lower press stage 4 and the upper press stage 9. Further, the operator brings the tip of the thermocouple 10 into contact with the outer peripheral surface of the set mold S (spacer 19).

When the above preparation is completed, the operator closes the vacuum chamber 5 and operates the vacuum exhaust device 6 to suck the air in the vacuum chamber 5. The amount of suction by the vacuum exhaust device 6 is automatically adjusted so that the air pressure in the vacuum chamber 5 is maintained at 0.01 [Torr].

Next, the operator activates the power supply device 1 to supply a current to the heater 3 to heat the set mold S. Then, the molding temperature (7) exceeding the temperature at which the base member 18 softens.
(About 00 ° C.).
In a state where the set mold S is kept at the molding temperature, the operator operates the weight control system 13 to cause the piston 7 to protrude by the hydraulic device 8 and press the upper press stage 9 with a pressing force of 200 kgf / cm ^2. Is pressed against the lower press stage 4 via the.

Then, the transfer substrate type 15 of the set type S is
Since the upper press stage 4 presses the transfer member 15 in the direction of the holding members 16 and 17, the transfer molding surface 15
b is pressed against the base member 18 which has been softened at the molding temperature. The transfer base die 15 is guided by the sliding holes 14 a of the body die 14, and is displaced downward until the upper end of the transfer base die 15 is at the same height as the upper end of the spacer 19. On this occasion,
The base member 18 has an upper part on which the holding surface 1 of the holding member 16 is attached.
6c, the transfer molding surface 15b of the transfer base die 15 is transferred to the upper end surface thereof.
The lower cylindrical portion 8 receives the pressing force of the transfer base die 15 and expands in the radial direction, so that the holding portion 16
d and press it against the lower surface.

The upper press stage 9 is provided on the end face of the spacer 19.
Abuts, the operator maintains the pressure of the hydraulic device 8 in a state where the pressure is reduced to 50 Kgf / cm ^{2 of the} holding pressure during cooling, stops the power supply device 1, and lowers the temperature of the set mold S. As a result, when the set mold S is sufficiently cooled, the operator opens a valve (not shown) of the vacuum exhaust device 6 to return the pressure in the vacuum chamber 5 to the atmospheric pressure, and operates the weight control system 13 to reduce the hydraulic pressure. The piston 7 is retracted by the device 8 and the set mold S is taken out of the vacuum chamber 5. Then, the set mold S is disassembled and the sliding hole 1 of the body mold 14 is disassembled.
The base member 18 and the holding members 16 and 17 which have been integrally formed are taken out of 4a.

On the base member 18, a concave surface having a shape obtained by inverting the transfer molding surface 15 b (convex surface) of the transfer base die 15 is transferred, and the worker places the concave surface of the base member 18 on the concave surface.
By forming thin films made of various ceramics, gold, platinum, platinum-based metals and other noble metals by a method such as sputtering or ion plating, the lens forming surface 18a of the base member 18 is finished.
The mold 91 is completed.

The mold 91 thus obtained is
As shown in FIG. 3, the base member 18, the holding member 16,
The base member 18 has a lens molding surface 18a of a predetermined shape for obtaining a desired lens surface, and the holding member 16 fixes the molding die 91 at the time of lens production. Collar part 1 necessary for
6b and a sliding portion 16a for guiding the sliding operation.

Further, the base member 18 after the molding process is filled in a state in which the inner surface below the holding portion 16d of the holding member 16 is also in contact with the gap without any gap, so that the narrowest space in the space within the holding member 16 is obtained. This means that the holding portion 16d is fixed. Accordingly, no matter how the mold 91 is arranged, the base member 18 does not come off the holding member 16. Thus, the mold 91 can be used not only as a lower mold but also as an upper mold when manufacturing a lens. Here, the mold 91 is used for both the upper mold and the lower mold. Therefore, the operator prepares two molds 91 corresponding to a pair of surfaces of the lens to be manufactured.

Then, the person in charge of manufacturing the lens, of the two molds 91 prepared in advance by the worker,
One is set as an upper mold and the other is set as a lower mold, and is set in a mold manufacturing apparatus (not shown) for manufacturing a lens, and the optical material for the lens interposed between the upper mold and the lower mold is pressed at a predetermined temperature. As a result, the shapes of the lens forming surfaces 18a of the two molds 91 are reverse-transferred to the optical material, respectively, to manufacture a lens having a desired lens surface.

As described above, according to the present embodiment, the base member 18 and the holding members 16 and 17 are integrally formed by the glass molding method to form the molding die 91 having the required shape. Since it can be manufactured, there is no need for a step of further processing and manufacturing the collar portion or the sliding portion after processing the lens molding surface. Therefore, the mold 91 can be easily manufactured in a short time.

The holding member 16 of the molding die 91
Has a rotationally symmetric holding surface 16c for positioning and holding the base member 18, and the rotationally symmetric axis of the holding surface 16c coincides with the center axis of the sliding portion 16a.
The central axis of c coincides with the pressing direction of the apparatus P when the mold 91 is manufactured. Therefore, the eccentricity of the base member generated at the time of pressing can be reduced.

In addition, since the holding members 16 and 17 of the molding die 91 are made of a high-strength material, the sliding portions 16a and the brim portions 16b to which a particularly large force is applied at the time of lens production are also highly durable. Has the property.

Therefore, even if the lens production is repeated using the molding die 91, the holding members 16, 17 can be reused even when the lens molding surface 18a of the base member 18 becomes unusable. That is, by removing the old base member 18 from the mold 91 and performing the above-described steps again, the mold 91 can be reproduced. At this time, since the transfer base die 15 requiring high-precision processing has already been manufactured, the remanufacturing operation can be completed easily and in a short time.
Since the holding members 16 and 17 are configured by combining two members, when removing the base member 18 from the holding members 16 and 17 in the remanufacturing operation of the molding die 91, the second holding member is used. The member can be removed from the first holding member 16 and the operation is easy.

[Second Embodiment] This embodiment is different from the first embodiment in that the transfer base mold 15, the holding members 16, 17 and the base member 18 are replaced with the first embodiment. The present embodiment is characterized in that the mold 92 of the present embodiment is manufactured by using the transfer base mold 25, the holding member 26, and the base member 28 which are the same in material but different in shape. Since the other configuration is the same as that of the first embodiment, the description will be made here focusing on the transfer base die 25, the holding member 26, and the base member 28.

As shown in FIG. 4, the transfer substrate die 25 has a cylindrical portion 25a, a transfer molding surface 25b, and an edge portion 25c, and has substantially the same shape as the transfer substrate die 15 of the first embodiment. A cylindrical portion having a slightly smaller diameter than the cylindrical portion 25a slightly protrudes from the tip of the portion 25a, and a transfer molding surface 25b of a predetermined shape for obtaining the lens molding surface 28a is formed at the tip of the small diameter cylindrical portion. The only difference is what was done.

The holding member 26 is not formed of two members like the holding members 16 and 17 of the first embodiment, but is formed of a single member.
Having a cylindrical outer peripheral surface (slidable portion 26)
a), and a flange 26b projecting radially from the lower end of the cylinder.

The outer diameter of the sliding portion 26a is slightly smaller than the inner diameter of the sliding hole 14a of the body mold 14 (φ19.988 ± 0.001).
mm), and the outer diameter of the collar portion 26b is
The sliding hole 14a is formed to have a diameter larger than the inner diameter and smaller than the outer diameter of the sliding hole 14a. The outer peripheral surface of the sliding portion 26a is processed to have a surface roughness required for sliding.

The inside of the sliding portion 26a has an accommodating wall 26c formed in a cylindrical shape from the upper opening end.
At an upper end of the housing wall 26c, a grip portion 26d is formed to protrude inward in a flange shape. The holding surface 2 having a shape formed by tapering the tapered shape deeper than a shape (lens surface shape) obtained by inverting the transfer molding surface 25b of the transfer base die 25 below the lower end of the housing wall 26c.
6e are formed. These housing wall 26c and grip 2
6d and the holding surface 26e correspond to an accommodation hole. Further, from the lower end of the holding surface 26e, a fine hole 26f opening to the lower end surface of the holding member 26 is formed.

The sliding portion 26a, the collar portion 26b, the housing wall 26c, the grip portion 26d, the holding surface 26e, and the fine hole 26
The respective central axes of f coincide with each other, and the holding member 26 is rotationally symmetric with respect to the central axis. In addition, the position moved in the radial direction from the central axis of the transfer base die 25 on the upper end surface of the transfer base die 25 by the length from the central axis of the holding member 26 to the innermost end surface thereof. The sum of the length taken from the reference position to the transfer molding surface 25b in parallel with the central axis of the transfer base die 25 and the length from the upper end surface to the lower end surface of the holding member 26 is the axis of the spacer 19. Direction length or less.

The base member 28 has a cylindrical upper portion having substantially the same diameter as the inner diameter of the holding portion 26d, and a holding surface 26e of the holding member 26.
And a tapered lower portion substantially corresponding to the above. The upper surface of the base member 28 is processed so as to approximate a shape obtained by inverting the lens surface, not a flat surface.

The transfer base die 25, the holding member 26, and the base member 28 together with the body die 14 and the spacer 19 constitute a set die S '. That is, the body mold 14 is fitted into the spacer 19, and the holding member 26 is fitted from the lower end of the body mold 14, and the holding member 26 has a lower end surface of the flange 26 b of the spacer 19. It is arranged so that it may ride on the same plane as the lower end surface, and the upper end of the collar portion 26b is in contact with the lower end of the body mold 14. The upper portion of the base member 28 is fitted into the holding portion 26d of the holding member 26, and the lower portion of the base member 28 is in contact with the holding surface 26e of the holding member 26. Further, a cylindrical portion 25a of the transfer base die 25 is fitted from the upper opening of the body die 14 such that the transfer molding surface 25b is in contact with the upper end surface of the base member 28.

In this state, the edge 25 of the transfer base mold 25 is
c The lower end does not contact the upper end of
4 is located slightly above. The upper end of the edge 25c of the transfer base die 25 projects slightly above the upper end of the spacer 19, and the height of the protrusion is
c is set smaller than the gap between the lower end and the upper end of the body mold 14. That is, the shape of each part constituting the set mold S ′ is determined so that the transfer base mold 25 takes such a position. Then, the base member 28 is pushed downward by the transfer base die 25 by the displacement from the upper end of the spacer 19 to the upper end of the transfer base die 25.

The set mold S ′ having the above configuration is incorporated in the manufacturing apparatus P, and the mold 92 is manufactured in the same procedure as in the first embodiment. The base member 28 is pressed toward the holding surface 26e of the holding member 26 by the transfer base mold 25 in a state of being softened at a predetermined temperature, so that the transfer molding surface of the transfer base mold 25 is formed on the upper surface of the base member 28. 2
The concave surface corresponding to 5b (convex surface) is transferred. Further, the upper cylindrical portion of the base member 28 is provided with a transfer base mold 25.
The base member 28 expands in the radial direction under the pressing force of the base member 28, and the outer peripheral surface of the base member 28 comes into pressure contact with the housing wall 26 c and the holding portion 26 d of the holding member 26. Accordingly, the holding member 26d narrower than the housing wall 26c of the holding member 26 is in a state in which the holding member 26d is indented from the outer periphery to the inside of the base member 28, and the base member 28 is held by the holding member 26d. Will be fixed. Thus, the base member 28 does not come off the holding member 26.

The composite of the holding member 26 and the base member 28 obtained by disassembling the set die S ′ taken out from the molding die manufacturing apparatus P has a thin film made of a noble metal or the like on the surface of the base member 28. By forming the film, a mold 92 having a lens forming surface 28a as shown in FIG. 5 is completed.

[Third Embodiment] This embodiment is different from the first embodiment in that the transfer base die 15, the holding members 16, 17 and the base member 18 are replaced with the second base member. The transfer base mold 35, the holding members 36 and 37, and the base member 38 which are made of the same material as in the first embodiment but differ only in shape.
Is used to obtain the mold 93 of the present embodiment. Since the other configuration is the same as that of the first embodiment, the description will be made here focusing on the transfer base die 35, the holding members 36 and 37, and the base member 38.

As shown in FIG. 6, the cylindrical portion 35a and the edge portion 35c of the transfer substrate die 35 have the same shape as the cylindrical portion 15a and the edge portion 15c of the transfer substrate die 15 of the first embodiment. Only the shape of the transfer molding surface 35b of the transfer base die 35 is different from the transfer molding surface 15b of the first embodiment. That is, only the central portion of the lower surface of the transfer base mold 35 protrudes in an aspherical shape (or a spherical shape) for obtaining a lens molding surface 38a of a molding die 93, which will be described later. The surface radially outside of the protruding portion is a flat surface.

The first holding member 36 has a cylindrical sliding portion 36a that can be fitted into the sliding hole 14a of the body die 14, and a flange portion 36b that projects radially from the lower end of the sliding portion 36a.
And an upper portion projecting upward from the upper end of the sliding portion 36a in a cylindrical shape smaller in diameter than the outer diameter of the sliding portion 36a and coaxial with the central axis of the sliding portion 36.

The outer diameter of the sliding portion 36a is slightly smaller than the inner diameter of the sliding hole 14a of the body mold 14 (φ19.988 ± 0.001).
mm), and the outer diameter of the collar portion 36b is
The sliding hole 14a is formed to have a diameter larger than the inner diameter and smaller than the outer diameter of the sliding hole 14a. The outer peripheral surface of the sliding portion 36a is processed to have a surface roughness required for sliding.
A male screw 36c is formed on the outer periphery of the columnar portion protruding upward from the upper end of the sliding portion 36a. Further, inside the male screw 36c portion of the holding member 36,
A holding surface 36d is formed as a receiving hole which is cut out in a tapered shape so that the upper end is opened. From the lower end of the holding surface 36d, a fine hole 3 opening to the lower end surface of the holding member 36 is formed.
6e are formed.

The second holding member 37 includes a cylindrical portion having a diameter slightly smaller than the outer diameter of the sliding portion 36a, a grip portion 37a protruding inwardly from above the cylindrical portion and a cylindrical portion. And a female screw 37b cut into a lower portion of the inner surface of the portion and screwed with the male screw 36c of the first holding member 36. In addition, the inside of the holding part 37a is chamfered in a tapered shape having a narrowed upper end.

In a state where the two holding members 36 and 37 are screwed together, the sliding portion 36a, the flange portion 36b, the male screw 36c, the holding surface 36d, and the fine hole 3 of the first holding member 36 are formed.
The respective central axes of 6e and the central axes of the grip portion 37a and the female screw portion 37b of the second holding member 37 are all coincident, and the holding members 36 and 37 are rotationally symmetric with respect to the central axis. It has become.

Further, the first holding member 37 in the state where the two holding members 36 and 37 are screwed to each other from the upper end surface of the second holding member 37
The sum of the length of the holding member 36 to the plane including the upper end of the flange 36b and the length from the plane including the lower end of the edge 35c of the transfer base 35 to the flat surface at the lower end of the transfer base 35 is the body shape. 14 or less.

The base member 38 is provided on both ends of a flat cylinder.
Two truncated cones of the same shape are integrally preformed so that the bottom surfaces of both truncated cones are in contact with both end surfaces of the cylinder, respectively. The side surface portion (lower tapered portion) of one of the truncated cones is in contact with the holding surface 36d of the holding member 36, and the side surface portion (upper tapered portion) of the other truncated cone is the holding member. 37 grips 37
The holding members 36 and 37 are assembled so as to be in contact with a.

As described above, the base member 38 is
Base member 38 in a state of being assembled in 6, 37
The sum of the length from the upper end to the plane including the upper end surface of the flange 36b of the holding member 36, the length from the plane including the lower end surface of the edge 35c of the transfer base die 35 to the center of the transfer molding surface 35b, and The difference between the axial length of the mold 14 and the sum of the length from the upper end of the base member 38 to the lower end of the holding member 36, the length from the upper end surface of the transfer base mold 35 to the center of the transfer molding surface 35b, and the spacer 19 difference from the axial length;

The transfer base die 35, the holding member 36, and the base member 38, together with the body die 14 and the spacer 19, constitute a set die S ″. That is, the body mold 14 is fitted into the spacer 19, and the holding member 36 is fitted from the lower end of the body mold 14, and the holding member 36 is connected to the lower end surface of the flange 36b and the spacer 19. Are arranged so that the lower end faces thereof are on the same plane, and the upper end of the collar portion 36b is in contact with the lower end of the body mold 14. And the base member 3
8, the lower tapered portion is the holding surface 3 of the holding member 36.
6d. Further, the cylindrical portion 35a of the transfer base die 35 is fitted from the upper opening of the body die 14 so that the transfer molding surface 35b and the upper end surface of the base member 38 are in contact with each other.

In this state, the edge 35 of the transfer base die 35
c The lower end does not contact the upper end of
4 is located slightly above. Further, the upper end of the transfer base die 35 projects slightly above the upper end of the spacer 19, and the height of this protrusion is larger than the gap between the lower end of the edge 35 c of the transfer base die 35 and the upper end of the body die 14. It is set small. That is, the shape of each part constituting the set mold S ″ is determined so that the transfer base mold 35 takes such a position. Then, the upper end of the edge 35 c of the transfer base die 35 is pushed down to the position of the upper end of the spacer 19, and the base member 38 is pressed toward the holding member 36.

The set type S ″ having the above-described configuration is connected to the manufacturing apparatus P
And a molding die 93 is manufactured in the same procedure as in the first embodiment. The base member 38 is pressed in the direction of the holding surface 36d of the holding member 36 by the transfer base mold 35 in a state of being softened at a predetermined temperature, so that the transfer molding surface of the transfer base mold 35 is formed on the upper surface of the base member 38. The concave surface corresponding to 35b (convex surface) is reverse-transferred. Further, the base member 38 expands in the radial direction under the pressing force of the transfer base die 35, and the outer peripheral surface of the base member 38 is
The holding member 36 is pressed against the holding surface 36d of the holding member 36 and the holding portion 37a of the holding member 37. Thereby, the base member 3
Numeral 8 is fixedly held between the holding surface 36d and the grip portion 37a.

The composite of the holding member 36 and the base member 38 obtained by disassembling the set die S ″ taken out from the forming die manufacturing apparatus P is provided on the surface of the base member 38 by a thin film made of a noble metal or the like. Is formed into a mold 93 having a lens forming surface 38a as shown in FIG.

As a result of repeating the lens production using this mold 93, the lens molding surface 38 of the base member 38 is obtained.
When a becomes unusable, the operator can easily remove the base member 38 from the holding members 36 and 37 by detaching the second holding member 37 from the first holding member 36. Therefore, not only the production operation of the molding die 93 but also the reproduction operation becomes easy.

[0088]

According to the present invention, a high-strength mold can be easily manufactured according to the present invention. According to the fourth aspect of the present invention, the lens forming surface of the base member in the mold has a holding surface having a rotationally symmetric axis as an axis coinciding with the sliding operation direction at the time of manufacturing the lens. A lens can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a mold manufacturing apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing a set mold according to the first embodiment.

FIG. 3 is a longitudinal sectional view showing a mold according to the first embodiment.

FIG. 4 is a longitudinal sectional view showing a set mold according to a second embodiment.

FIG. 5 is a longitudinal sectional view showing a mold according to a second embodiment.

FIG. 6 is a longitudinal sectional view showing a set mold according to a third embodiment.

FIG. 7 is a longitudinal sectional view showing a mold according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power supply 3 Heater 4 Lower press stage 7 Piston 8 Hydraulic device 9 Upper press stage 14 Body type 15 Transfer base type 15a Transfer molding surface 16 First holding member 16a Sliding portion 16b Collar portion 16c Holding surface 16d Holding portion 17 Second portion Holding member 18 base member 18a lens forming surface 25 transfer base mold 25a transfer forming surface 26 holding member 26a sliding portion 26b flange 26d gripping portion 26e holding surface 28 base member 28a lens forming surface 35 transfer base mold 35a transfer forming surface 36 First holding member 36a Sliding portion 36b Collar portion 36d Holding surface 37 Second holding member 37a Gripping portion 38 Base member 38a Lens forming surface P Mold forming apparatus S, S ', S' 'Set mold

Claims (14)

[Claims] 1. A molding member used for molding a lens having a lens surface having a predetermined shape, wherein a base member having a lens molding surface having a predetermined shape for obtaining said lens surface is formed on an end surface. An accommodation hole for accommodating the base member at one end, fixing means for fixing the mold at the other end, and a sliding portion for guiding a sliding operation when molding the lens on a side surface;
And a columnar holding member having the following. 2. The base member is made of a material having a softening point higher than the softening point of the optical material for the lens, and the holding member is made of a material which is higher in temperature and harder than the base member. The mold according to claim 1, wherein: 3. The holding member according to claim 1, wherein said sliding portion has a cylindrical surface, and said fixing means is formed as a collar portion projecting annularly from said sliding portion. Alternatively, the mold according to claim 2. 4. The holding member includes a holding surface which is rotationally symmetric with respect to a center axis of a sliding portion of the holding member on an inner surface of the receiving hole, and positions the base member on the holding surface. The mold according to claim 3, wherein the mold is held. 5. The mold according to claim 4, wherein the holding surface has a shape in which a side surface of a cone or a truncated cone is inverted. 6. The holding member according to claim 1, wherein the holding member has a shape in which the inner surface of the accommodation hole is narrowed, and includes a holding portion for holding and fixing the base member. The mold described in the above. 7. The mold according to claim 6, wherein the holding portion of the holding member is rotationally symmetric with respect to a center axis of a sliding portion of the holding member. 8. The holding member comprises a member on the side where the receiving hole of the holding member is opened and a member on the back side of the receiving hole are detachably engaged with each other. 8. The mold according to claim 6, wherein the member on the opening side is provided with the grip portion. 9. The molding die according to claim 1, wherein said base member and said holding member are combined and integrally molded by a molding method. Production method. 10. The mold according to claim 9, wherein said lens molding surface of said base member is formed simultaneously with said composite integral molding of said base member and said holding member by said molding method. Method of manufacturing. 11. A transfer substrate mold having a transfer molding surface of a predetermined shape for obtaining the lens molding surface is prepared in advance, and the transfer molding surface of the transfer substrate mold is reversely transferred to the substrate member by a molding method. 11. The method according to claim 9, wherein the lens molding surface is formed on the base member. 12. The method according to claim 9, wherein a release film is further formed on the lens forming surface formed on the base member. 13. An apparatus for manufacturing a molding die used for molding a lens having a lens surface having a predetermined shape, wherein a transfer molding surface having a predetermined shape for obtaining the lens molding surface according to claim 1 is provided. A transfer base mold having a base member that softens under heating, and a holding member according to any one of claims 3 to 8, a heating device that heats the base member and the holding member, and transfer molding of the transfer base mold. And a pressing mechanism for pressing a surface against the base member. 14. The transfer base mold further includes a cylindrical body die for inscribing a sliding portion of the holding member, and the transfer base mold has the transfer molding surface formed on a tip end surface thereof and the transfer mold surface is formed on the body mold. 14. The apparatus for manufacturing a mold according to claim 13, further comprising a cylindrical portion which is slidably inscribed.