KR20060058759A - Mold press forming mold and method for producing optical element - Google Patents

Abstract

Let the axial length of the large diameter part 11 (large part) of the upper mold 10 be L1, and let the axial length of the small diameter part 12 (small part) of the upper mold 10 be L2. When L1 > L2 is established and the large diameter portion 21 of the lower mold 20 (stop mold) is accommodated in the second inner circumferential large diameter portion 33 of the fuselage mold 30, the fuselage mold 30 ) Abuts against the flange 22 of the lower mold 20, thereby defining the mutual position of the lower mold 20 and the fuselage mold 30, the upper mold 10 has a sliding clearance of 10㎛ or less When the length in the axial direction of the portion slid to the body mold 30 is set to L, and the total length in the axial direction of the body mold 30 is set to S, L? 0.5S is established.

Description

MOLD PRESS FORMING MOLD AND METHOD FOR PRODUCING OPTICAL ELEMENT}

1 is a cross-sectional view of a mold press molding mold according to a first embodiment of the present invention.

FIG. 2 is a view for explaining the operation of the mold press-molding mold of FIG. 1, illustrating a relationship between sliding guide length, clearance, and tilt. FIG.

It is sectional drawing of the mold press molding mold which concerns on 2nd Embodiment of this invention.

4 is a view for explaining a manufacturing method of the optical element according to the embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: upper mold (sliding mold) 11: large diameter portion

12: small diameter portion 13: shaping surface

14 middle diameter portion 20 lower mold (stop mold)

21: large diameter portion 22: flange portion

23: small diameter portion 24: forming surface

30: fuselage mold 31: first inner circumference large diameter portion

32: small inner ring portion 33: second large inner ring portion

34: vent hole 35: inner diameter middle diameter

40: molding material 50: press load applying means

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a mold press molding mold and an optical element manufacturing method for forming an optical element such as a glass lens, in particular an eccentric precision having a very high eccentricity and used for an optical optical element used in an optical pickup, a miniature imager, or the like.

BACKGROUND ART A method of manufacturing optical elements such as lenses is known by press-molding a molding material such as glass by pressing with a pair of upper and lower molding molds which are softened by heating and precisely processed into a predetermined shape (for example, Japanese Patent Laid-Open No. 2002- 29763 (patent document 1) and Japanese Utility Model Publication H4 (1992) -14429 (patent document 2)).

Patent Document 1 describes a molding mold for molding a micro lens having a very small coma aberration. Here, while restricting the access directions of the upper mold and the lower mold by the first fuselage mold, the upper mold and the lower mold are pressed against the second fuselage mold disposed on the outer circumference of the first fuselage mold until the upper mold and the lower mold come into contact with each other. The glass molded body is further pressed by cooling the molded body and the molding mold under the condition that the heat shrinkage amount in the vertical direction of the second body mold becomes equal to or greater than the heat shrinkage amount of the glass molded body.

In Patent Literature 2, the guide portion of the inner diameter of the fuselage mold and the outer diameter of the pair of molds has two stages, and a gap between the mold of the first portion having a large diameter close to the end of the fuselage mold is formed in the cavity. A mold for a lens is disclosed, which is smaller than a second portion having a smaller diameter and has a shorter length of a mold fitted with the first portion of the fuselage mold compared to a first portion having a larger diameter of the fuselage mold. have. As a result, the assembly can be performed smoothly in a state where the matching accuracy of the central axes of the pair of molds is improved.

BACKGROUND ART Optical lenses used in portable image pickup machines, optical pickups, and the like require very high optical performance and need to be highly accurate aspherical lenses. In addition, in order to achieve both miniaturization and high performance of the lens system, the radius of curvature is smaller than in the related art, and the inclination angle of the lens surface around the lens surface becomes 40 degrees or more, and in some cases 50 degrees or more. Such aspherical lenses have a very small tolerance for eccentricity and thickness accuracy compared to conventional aspherical lenses, which makes it difficult to press a precise mold.

In addition, the eccentricity accuracy of the optical element is generally the distance between the axis of the first surface and the axis of the second surface, which are optically functional surfaces of the optical element (shifting, corresponding to the horizontal deviation of the upper and lower molds during molding), It evaluates by the inclination (tilt) between the axis | shaft of one surface and the axis | shaft of the 2nd surface.

Furthermore, in the case of a high-precision imaging lens having a small diameter in a digital camera or a mobile terminal, or an objective lens of NA 0.6 or more among optical pickup lenses, the shift of the first surface and the second surface is set to 10 µm or less, and the tilt is performed. Should be in the range of 3 min or less, preferably 2 min or less. For this reason, in the shaping | molding mold used for precision press molding, the relative positional precision between molds is raised by reducing the clearance gap between the two molds which shape each surface of a lens, and the fuselage mold which hold | maintains these.

In addition, the outer diameter of a lens such as an imaging lens or optical pickup lens having a small diameter is reduced to 5 mm or less in diameter and, in some cases, 3 mm or less. In order to obtain such a small-diameter lens without a post-processing step such as deep chamfering, the mold diameter of the press mold and the inner circumferential diameter of the fuselage mold become narrow. Since it is necessary to press-mold with a narrow molding mold with a small gap as described above, it is very difficult to smoothly insert or slide the molding mold when assembling, disassembling, press molding, or the like. Breakage of the mold, such as cracking or bending, is likely to occur.

According to the shaping | molding mold of patent document 1, it is described that the lens of the favorable precision with small inclination (tilt) of the upper and lower mold at the time of press molding can be obtained. However, when the lens having a small diameter is to be molded, since the upper mold diameter becomes small, the upper mold shape is easily broken. In particular, when the upper mold is slightly inclined when the upper mold is inserted into the first fuselage mold, the upper mold is easily broken or bent.

In addition, since the mold material is a high hardness material (hard material) such as ceramic or carbide, when the inner circumferential surface of the body mold is a long hole having a diameter of 3 mm or less, required dimensional accuracy (hole diameter) and shape precision (hole) It is not easy to manufacture with a processing error of several microns or less so as to satisfy the roundness, the cylinder degree, the squareness, etc.).

In the mold described in Patent Document 2, the outer diameter of the mold close to the cavity is made smaller than the other parts to be made in two stages, and the gap is appropriately set, whereby the mold and the fuselage mold are fitted in a portion having a large outer diameter away from the cavity. It is configured to carry out the guidance. Thereby, a metal mold | die can be assembled smoothly to a fuselage mold in the state which improved the matching accuracy of the center axis | shaft of a pair of metal mold | die. In fact, when such a structure is used, since the press molding can be performed in the small diameter part of a fuselage mold without contact with a pair of metal mold | die, it is thought that a pair of metal mold | die damage is reduced.

However, the mold disclosed herein has the following problems. That is, a pair of molds (called an upper mold and a lower mold) are formed with a flange. Each of the flanges abuts against both ends of the fuselage mold, thereby restricting the access of the upper and lower molds and ending the press. Thereafter, the mold and the molding material are cooled to remove the molded body after the molding material is solidified. When the molding material shrinks during the cooling process, the mold surface and the molded body fall, so that the surface shape is broken. This is because the flanges of the upper and lower molds are restricted by the fuselage mold ends and are no longer accessible.

Such a mold can be used as long as the surface precision of the molded body is not so required. However, the mold can hardly be employed in a high-precision mold lens used for the above-mentioned use.

Therefore, it is considered to cut out the flange portion of the upper mold disclosed in Patent Document 2 so that the upper mold can follow the shrinkage during cooling of the molded body. However, since the upper mold flange does not come into contact with the upper surface of the fuselage mold, the function of maintaining the coaxiality between the fuselage mold and the upper mold is lost. That is, the upper mold tends to fall within the fuselage mold within the range allowed by the sliding gap with the fuselage mold, and the tilt (tilt) of the first and second surfaces deteriorates in the molded lens. . This becomes a problem for the lens of the said use with high required precision, and cannot be avoided only by making a sliding clearance small.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to reduce the sliding gap of the sliding mold while preventing mold breakage, and to suppress the sliding mold from falling down, thereby forming an optical element with high eccentricity precision. The present invention provides a method for manufacturing a mold press molding mold and an optical element.

In order to achieve the above object, the mold press-molding mold of the present invention is capable of inserting the sliding mold and the stop mold having the molding surfaces facing each other, and the sliding mold and the stop mold from both ends, respectively, A mold press-molding mold having a fuselage mold for slidingly guiding the sliding mold in the mold press, wherein the sliding mold has a larger diameter portion and a smaller diameter than the large diameter portion, and has the molding surface at the tip. A small diameter portion is provided, and L1> L2 is established when the length in the axial direction of the large diameter part in the sliding mold is set to L1 and the length in the axial direction of the small diameter part in the sliding mold is set to L2. The stop mold includes a large diameter portion and a small diameter portion having a diameter smaller than that of the large diameter portion and having a molding surface formed at a tip thereof, and the body mold includes: A first inner circumferential portion for accommodating and slidingly guiding the large diameter portion of the sliding mold; an inner circumferential small portion for accommodating the small diameter portion of the sliding mold; and a second inner circumferential portion for accommodating the large diameter portion of the stationary mold. When the sliding mold has a sliding clearance of 10 μm or less, the length in the axial direction of the portion slidingly guided to the fuselage mold is L, and when the total length in the axial direction of the fuselage mold is S, L ≧ 0.5 It is a structure in which S is established.

In this way, while preventing mold breakage, the sliding gap of the sliding mold can be reduced, and the range in which the sliding mold is slid to the small sliding gap can be increased. Thereby, the sliding mold can be suppressed from falling down, and an optical element with high eccentricity precision can be formed.

In addition, the mold press molding mold of the present invention may have a configuration in which L = L1 is established.

In this configuration, the maximum fall angle of the sliding mold is defined by the relationship between the sliding gap C1 in the large diameter portion of the sliding mold and the axial length L1 in the large diameter portion of the sliding mold, thereby providing the desired eccentric accuracy. An optical element that satisfies can be obtained. That is, the tilt of the optical element to be molded can be controlled by C1 and L1.

Preferably, the stop mold includes a flange portion having a larger diameter than the large diameter portion, and when the large diameter portion of the stop mold is accommodated in the second inner circumferential diameter portion of the fuselage mold, the flange portion of the stop mold is the fuselage body. By contacting a mold, mutual position of the said stop mold and the said fuselage mold can be prescribed | regulated.

Further, in the mold press molding mold of the present invention, when a predetermined amount of the sliding mold is inserted into the fuselage mold, a part of the sliding mold becomes coplanar with a part of the fuselage mold and exceeds the predetermined amount. The sliding mold can be further inserted into the fuselage mold.

By doing in this way, the amount of the sliding mold inserted into the fuselage mold can be controlled constantly, and furthermore, since the sliding mold can follow the shrinkage of the molded body thereafter, it is possible to prevent deterioration of surface precision due to shrinkage of the molded body. Can be.

Further, in the mold press-molding mold of the present invention, when the gap between the large diameter portion of the sliding mold and the first inner large diameter portion of the fuselage mold is C1, L1? C1 / sin? (Where θ ≤ 3 min) is established. It is preferable to comprise so that.

In such a configuration, by selecting the sliding gap C1 at the large diameter portion of the sliding mold and the axial length L1 at the large diameter portion of the sliding mold, an optical element that satisfies the tilt within 3 minutes can be obtained.

Moreover, the mold press molding mold of this invention makes the clearance gap between the large diameter part of the said sliding mold, and the 1st inner peripheral big diameter part of the said fuselage mold C1, The small diameter part of the said sliding mold, and the inner peripheral diameter of the said fuselage mold, When setting the gap of C2 to C2, it is preferable to configure so that C1 < C2 is established.

If comprised in this way, the possibility that the small diameter part of a sliding mold may be damaged by contact with a fuselage mold can be reduced more effectively.

In addition, in the mold press molding mold of the present invention, when the sliding mold is used as the upper mold and the stationary mold as the lower mold, and the upper mold is inserted in a predetermined amount relative to the fuselage mold, the upper surface of the upper mold is the fuselage. It is preferable to comprise so that a plane which becomes coplanar with the upper surface of a mold may be provided.

When comprised in this way, by making the upper surface of an upper mold and the upper surface of a fuselage mold coplanar at the time of press molding, it can further suppress that an upper mold falls. Moreover, since the insertion amount of the upper mold can be regulated constantly, the thickness precision of the molded body can be improved.

Moreover, it is preferable that the mold press molding mold of this invention is comprised so that the internal diameter of the 2nd inner peripheral diameter part of the said fuselable mold may be smaller than the internal diameter of the 1st inner peripheral diameter part of the said fuselage mold.

With this arrangement, even if sliding of the stationary mold on the second inner circumferential diameter part is repeatedly performed during the assembly and disassembly of the molding mold, the sliding frictional resistance during the sliding mold can be reduced, so that the fuselage mold and the stationary mold Scratches and wear on the liver can be suppressed.

In the mold press molding mold of the present invention, the diameter of the large diameter portion of the sliding mold is set to D1, the diameter of the small diameter portion of the sliding mold is set to D2, and the diameter of the small diameter portion of the stop mold is set to D3. When setting the diameter of the large diameter part of a stationary mold to D4, it is preferable to comprise so that D1 ≧ 2 · D2 and D4 ≧ 2 · D3 may be established.

In this way, the rigidity of the sliding mold and the stationary mold itself is increased, so that the mold can be prevented from being damaged during press molding or assembling and disassembling the molding mold.

Moreover, the manufacturing method of the optical element in this invention is a method of using the mold press molding mold in any one of the above in the manufacturing method of the optical element press-molded in the state which softened the molding material.

In this way, the sliding mold is prevented from falling down while preventing mold breakage, and an optical element having high eccentricity precision and thickness precision can be formed.

Moreover, the manufacturing method of the optical element of this invention is a manufacturing method of the optical element which supplies a molding material to a shaping | molding mold, press-forms with a shaping | molding mold, and cools the obtained molded object in the state which softened by heating. It is possible to cool the molded body in the mold, and to move the sliding mold in the fuselage mold in accordance with the shrinkage of the molded body during cooling.

Furthermore, in the method of manufacturing the optical element according to the present invention, the sliding mold is moved to the fuselage such that at least a portion of the sliding mold is flush with at least a portion of the fuselage mold in a state where a molding material is softened by heating. It may include a step of inserting at a predetermined pressure in the mold. Thereby, in addition to eccentricity and thickness precision, the surface precision of a spherical surface and an aspherical surface can be maintained still higher.

Furthermore, according to the present invention, the sliding mold and the stop mold having the forming surfaces facing each other, and the sliding mold and the stop mold can be inserted from both ends, respectively, and at least the sliding mold is a sliding guide during press molding. In the manufacturing method of an optical element using a mold press molding mold having a fuselage mold, the length of the axial direction of the portion of the sliding mold sliding guide to the fuselage mold with a sliding gap of 10㎛ or less, L When the sliding gap is set to C and the allowable value of the mutual inclination angle of the two optical functional surfaces having the optical element to be obtained is θ,

L ≥ C / sinθ

By selecting L and C satisfying the above, the dimensions of the sliding mold and the fuselage mold are determined to obtain a method for manufacturing an optical element.

By determining the size of the molding mold and managing the accuracy in this way, quality control of the eccentric accuracy of the lens and the optical performance of the lens can be indirectly performed.

As mentioned above, according to this invention, while suppressing mold breakage, the sliding clearance of a sliding mold can be made small, and the range in which a sliding mold slides to a small sliding clearance can be lengthened. As a result, the sliding mold can be suppressed from falling down, and an optical element with high eccentricity precision and thickness precision can be formed.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described with reference to drawings.

[Mold Press Molding Mold (First Embodiment)]

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the mold press molding mold which concerns on 1st Embodiment of this invention, and FIG. 2 is a figure which shows the relationship of a sliding guide length, a clearance gap, and a tilt.

As shown in FIG. 1, a mold press molding mold (hereinafter, simply referred to as a 'molding mold') includes an upper mold 10, a lower mold 20, and a body mold 30.

The upper mold 10 and the lower mold 20 are press-molded between the upper mold 10 and the lower mold 20 to form a molding material 40 (eg, a glass preform), or the molding material 40. In order to disassemble the molding mold at the time of supplying the molded article or taking out the molded article, it is possible to move the movable mold 30 to the body mold 30.

In addition, in the molding mold of the present embodiment, the upper mold 10 slides and the lower mold 20 is stopped at the time of press molding in which the molding material is pressed and molded between the upper and lower molds. 10), the sliding mold and the lower mold 20 is a stop mold.

The upper mold 10 includes a large diameter portion 11 having the largest diameter and a small diameter portion 12 projecting downward from the lower end of the large diameter portion 11. The shaping surface 13 of the upper mold 10 is formed at the tip of the small diameter portion 12, and the center of the shaping surface (in the case of aspherical surface, aspherical surface), and the outer circumferential surface of the large diameter portion 11 and the small diameter portion 12 The center of gravity is in agreement. Here, the diameter of the large diameter part 11 is D1, and the diameter of the small diameter part 12 is D2.

In response to the shape of the upper mold 10, the first inner circumferential large diameter 31, which accommodates the large diameter portion 11 of the upper mold 10 and slides during press molding, is placed on the upper part of the body mold 30. The inner peripheral small diameter part 32 which accommodates the small diameter part 12 of the upper mold 10 is formed. Here, the axis of the inner peripheral surface of the fuselage mold 30 is processed so that all may coincide. The inner diameter of the first inner circumferential diameter portion 31 is D1, and the inner diameter of the inner circumference small diameter portion 32 is D2 (unless otherwise specified, the diameter value is expressed without including only the sliding gap).

Here, when the length in the axial direction of the large diameter part 11 of the upper mold 10 is L1, and the length in the axial direction of the small diameter part 12 is L2, it is L1> L2. In this way, when the upper mold 10 is inserted from the upper end opening of the fuselage mold 30, first, the large diameter part 11 of the upper mold 10 contacts the fuselage mold 30, and the fuselage mold 30 After being slid by the first inner circumferential portion 31 of), the small diameter portion 12 of the upper mold 10 having a small diameter is brought into contact with the inner circumferential small diameter portion 32 of the fuselage mold 30. In this case). As such conditions are secured, it is possible to suppress the small diameter portion 12 of the upper mold 10 from suddenly contacting and damaging the body mold 30. This is particularly effective when the diameter of the small diameter portion 12 of the upper mold 10 is small (for example, when the lens to be obtained is 5 mm or less).

At this time, it is more preferable that L1 / (L1 + L2) ≧ 0.6, and furthermore L1 / (L1 + L2) ≧ 0.7.

In addition, in order to more reliably prevent breakage of the small diameter portion 12 and the forming surface 13 at its tip, it is preferable that D2 / D1? 0.25. However, when molding a lens having a small diameter, if the diameter D1 of the large diameter portion 11 is set to the same diameter as the diameter D2 of the small diameter portion 12, the rigidity and strength of the upper mold 10 Since the mold may be damaged due to scratches or the like during press molding or assembling and disassembling the molding mold, the diameter D1 of the large diameter portion 11 is increased to increase the rigidity and strength of the upper mold 10. It is preferable to set it as 2 times or more (D1≥2 * D2) of the diameter D2 of the small diameter part 12.

When the upper mold 10 is inserted from the upper end of the fuselage mold 30 during press molding, the large diameter portion 11 of the upper mold 10 is moved by the first inner circumferential diameter portion 31 of the fuselage mold 30. Is sliding guide. Between the large diameter part 11 of the upper mold 10, and the 1st inner peripheral diameter part 31 of the fuselage mold 30, the clearance C1 of 10 micrometers or less, Preferably 5 micrometers or less is ensured, By making the clearance C1 very small in the slidable range, the shift of the upper mold 10 in the fuselage mold 30 and the fall (tilt) of the upper mold 10 in the fuselage mold 30 are eliminated. You can limit it.

In addition, it is advantageous for the length L1 in the press axial direction of the large diameter part 11 in the upper mold 10 to be enlarged in the allowable range from the dimension of a shaping | molding mold.

Here, when the length of the axial direction of the part which the upper mold 10 slides to the fuselage mold 30 with the clearance within 10 micrometers is made into "sliding guide length L", when L = L1, C1 and This is because the maximum fall angle of the upper mold 10 is determined in the relationship of L1 (see FIG. 2).

On the other hand, when the length in the axial direction of the fuselage mold 30 is S, the length (S) is the theoretical maximum value that can slide guide the upper mold 10 in accordance with the shape of the fuselage mold 30, In the present invention, at least 1/2 or more of the axial length S of the fuselage mold 30 is applied to the sliding guide of the upper mold 10 (sliding mold). In other words,

L ≥ 0.5S (1)

Meets. If L = L1, L1> 0.5S. In addition, it is more preferable that L1> 0.6S.

Moreover, in order to obtain a large tilt suppression effect, 60% or more of S is used as the sliding guide length L. In other words,

L ≥ 0.6S (2)

It is preferable to set it as this, and it can further suppress that a sliding mold falls, and can improve the eccentricity precision of the optical element obtained.

Furthermore, it is preferable to set L≥0.5H with respect to the height H of the whole molding mold. That is, in the design of the shaping | molding mold, it is preferable to cover half or more of height components with respect to L which contributes to an eccentric performance.

In addition, as described above, in order to realize both miniaturization and high performance in the lens to be molded, it is preferable that the length of L1 satisfies the following conditional formula when the allowable upper limit of tilt is θ.

L1 ≥ C1 / sinθ (3)

Here, it is preferable that (theta) <3min. That is, when the upper limit of the fall angle of the upper mold 10 allowed in FIG. 2 is θ, since sinθ = C / L, the sliding guide length L satisfying L ≧ C / sinθ may be selected.

In other words, the sliding mold has a sliding gap of 10 μm or less, the length in the axial direction of the portion slid to the fuselage mold is set to L, the sliding gap is set to C, and two optical elements to be obtained When the allowable value of the mutual inclination angle of the optical function surface is θ,

L ≥ C / sinθ

By selecting L and C satisfying the above, it is possible to manufacture a lens having an eccentric precision of a certain level or more, and this can be applied as an index for quality control of the optical performance of the lens.

 In particular, in an aspherical lens, the mutual inclination of the two lens surfaces of the lens has a large influence on the optical performance of the lens, and in the case of a lens used in combination, the measurement of each lens is not easy. It is advantageous to control the quality of the lens by the precision and dimensions of the molding mold used for manufacturing. In this case, the values of L and C of the molding mold may be management indexes and evaluation indexes of the eccentric accuracy of the lens.

The small diameter portion 12 of the upper mold 10 is accommodated in the inner circumference small diameter portion 32 of the fuselage mold 30, and the gap C2 can be set to 10 µm or more, for example, 10 to 50 µm. . That is, it can be set as C1≤C2. By doing in this way, the possibility that the small diameter part 12 of the upper mold 10 breaks by the contact with the fuselage mold 30 can be suppressed more effectively.

In addition, the clearance gap C2 can also be 10 micrometers or less similarly to the clearance gap C1. In this case, the sliding guide length L which regulates the fall (tilt) of the upper mold 10 in the fuselage mold 30 becomes (L1 + L2), and the tilt of the upper mold 10 is adjusted only by L1. Compared with the case where it restricts, the length of the sliding guide can be made longer and the tilt can be made smaller. Also in this case, it is preferable to make (L1 + L2) large in the range allowable from the dimension of a shaping | molding mold. That is, the above formula (1) or (2) can be applied as L = L1 + L2. In this case, however, the coaxiality of the large diameter portion 11, the small diameter portion 12 of the upper mold 10, the first inner circumference large diameter portion 31, the inner circumference small diameter portion 32 of the fuselage mold 30, and the like. It is necessary to raise the degree.

On the other hand, the lower mold 20 has a larger diameter portion 21, which is the largest diameter portion of the portion that contacts or slides with the inner circumferential surface of the fuselage mold 30, and has a smaller diameter than the large diameter portion 21, and has a molding surface at the tip. It has the small diameter part 23 in which 24 was formed. Preferably, a flange portion 22 having a diameter larger than that of the large diameter portion 21 is provided, the upper surface of the flange portion 22 abuts against the lower surface of the fuselage mold 30, and the large diameter portion 21 is the fuselage mold. 30 is accommodated. In the structure of FIG. 1, the small diameter part 23 protrudes from the upper end of the large diameter part 21, and the shaping | molding surface 24 is formed in the front-end | tip. The lower mold 20 is processed so that the center of the forming surface (aspherical surface in the case of aspherical surface) and the axis of the large diameter portion 21 coincide with each other, and the upper surface of the flange portion 22 has a central axis of the forming surface 24. Vertically and smoothly machined.

Corresponding to the shape of the lower mold 20, a second inner circumferential diameter portion 33 for receiving the large diameter portion 21 of the lower mold 20 is formed below the fuselage mold 30. When the large diameter part 21 of the lower mold 20 is accommodated in the fuselage mold 30, the upper surface of the flange part 22 abuts on the lower surface of the fuselage mold 30. As shown in FIG. The lower surface of the fuselage mold 30 is planarly processed smoothly and perpendicularly to the axis of the fuselage mold 30.

The second inner circumferential diameter portion 33 of the fuselage mold 30 is preferably fitted into the large diameter portion 21 of the lower mold 20 in a narrow gap (C4; 10 μm or less, preferably 5 μm or less). Do. Therefore, as the lower mold 20 is inserted from the lower opening of the fuselage mold 30 and the smooth surfaces thereof are brought into close contact with each other, the mutual positions of the fuselage mold 30 and the lower mold 20 are defined with high precision. . And since the lower mold 20 is stopped in this state at the time of press molding, the tilt between the fuselage mold 30 and the lower mold 20 becomes substantially zero.

The diameter D4 of the large diameter portion 21 of the lower mold 20 may be the same as the diameter D1 of the large diameter portion 11 of the upper mold 10, but the large diameter portion 21 of the lower mold 20 may be used. It is preferable to make the diameter D4 smaller than the diameter D1 of the large diameter part 11 of the upper mold 10. By making the diameter D4 of the large diameter portion 21 of the lower mold 20 smaller than the diameter D1 of the large diameter portion 11 of the upper mold 10, the lower surface and the lower mold of the fuselage mold 30 during the press ( Since the area | region in which the upper surface of the flange part 22 of 20 is pressurized becomes large, it can suppress more effectively that the lower mold 20 falls.

In addition, in this embodiment, when the lower surface of the fuselage mold abuts on the upper surface of the flange of the fuselage mold, both of them are integrated and the mutual position is defined so that the tilt between the two can be prevented. Moreover, even if it is the structure which can prevent a tilt by holding a stationary mold and a fuselage mold integrally other than such a contact relationship, it can apply to this invention. For example, the lower surface of the large diameter part 21 of the lower mold 20 and the lower surface of the body mold 30 may be plane-processed with good precision, and may be fixed on the processed mounting table.

Here, for example, in the process of manufacturing optical elements by performing continuous press molding as described later (see FIG. 4), the molding material 40 is directed toward the fuselage mold 30 into which the upper mold 10 is inserted. Inserting the lower mold 20 disposed on the molding surface 24 to assemble the molding mold, the mold disassembly and lens extraction after press molding, the lower mold in the state that the upper mold 10 is inserted into the fuselage mold 30 This can be done by taking out the mold 20. In this case, sliding of the lower mold 20 is repeatedly performed during the assembly and disassembly of the molding mold, so that the lower mold 20 is lower than the sliding amount between the upper mold 10 and the fuselage mold 30 during press molding. ) And the sliding amount between the body mold 30 is increased. For this reason, it is important for stable production that the sliding frictional resistance which arises between the fuselage mold 30 and the lower mold 20 is made small, and the damage and abrasion between the fuselage mold 30 and the lower mold 20 is suppressed. Done.

The sliding frictional resistance generated between the fuselage mold 30 and the lower mold 20 can be made smaller as the sliding diameter is smaller and the sliding length is shorter, so that mutual scratches and wear during sliding can be suppressed. It is preferable that the inner diameter of the second inner circumferential large diameter portion 33 of the mold 30 is smaller than the inner diameter of the first inner circumferential large diameter portion 31. In this case, the diameter D4 of the large diameter portion 21 of the lower mold 20 can be made smaller than the diameter D1 of the large diameter portion 11 of the upper mold 10, and thus the lower mold described above. It is also effective in suppressing the fall of (20).

The inner circumferential small diameter portion 32 of the fuselage mold 30 has a structure in which the small diameter portion 12 of the upper mold 10 is accommodated in the upper portion, and the small diameter portion 23 of the lower mold 20 is accommodated in the lower portion. have. In the inner circumferential small diameter portion 32, if the clearance between the portion surrounding the forming surface 24 of the lower mold 20, that is, the portion forming the side surface of the lens is C3, C3 ≥ C1, C3 ≥ C2 have. In this way, when assembling the lower mold 20 to the body mold 30, it is possible to prevent cracks and scratches due to the contact of the peripheral edge of the forming surface 24.

Moreover, the height L4 of the large diameter part 21 of the lower mold 20 is a height required in order to acquire the vertical precision with the fuselage mold 30, and the axial direction of the small diameter part 23 in the lower mold 20 is carried out. When length is set to L3, L3 <L4 is preferable.

Further, in consideration of the distribution of the height components of the large diameter portion of the upper mold and the lower mold, it is preferable to make the upper mold, which is the sliding mold, higher than the lower mold, which is the stationary mold, and L4 &lt; L1. Furthermore, it is preferable that L4 <0.5L1.

In addition, when the height of the lower mold 20 is L5, L5 is the sum of the height L4 of the large diameter portion 21, the height L3 of the small diameter portion 23, and the height of the flange portion 22. , L5 is preferably smaller than the diameter (D5) of the flange portion (22). By doing so, the center of the lower mold 20 can be made at a relatively low position, so that the postural restoring force of the lower mold 20 with respect to the fine tilting when the lower mold 20 is inserted into the fuselage mold 30 is reduced. It can enlarge and can prevent the lower mold 20 and the fuselage mold 30 from being caught or scratched.

In the inner circumferential small diameter portion 32 of the fuselage mold 30, the diameter D3 of the lower side in which the small diameter portion 23 of the lower mold 20 is accommodated is determined based on the dimensions of the optical element to be obtained. According to the molding mold of the present invention, by molding the side surface of the optical element in the inner peripheral small diameter portion 32 on the lower side where the small diameter portion 23 of the lower mold 20 is accommodated, It is possible to avoid cutting off the peripheral edges. In this case, since the final shape can be obtained only by press molding, it is very useful for small diameter lenses that are difficult to carry out deep odor processing, and the productivity can be dramatically improved.

Moreover, it is preferable to make diameter D4 of the large diameter part 21 of the lower mold 20 more than twice the diameter D3 of the small diameter part 23. As shown in FIG. In this way, the rigidity and strength of the lower mold 20 are increased, and it is possible to prevent the lower mold 20 from being damaged due to scratches or the like during press molding or assembling and disassembling the molding mold.

The height (length L0 in the press axial direction) of the first inner circumferential large diameter portion 31 in the body mold 30 is preferably larger than the height L1 of the large diameter portion 11 of the upper mold 10. Do. That is, when the upper surface of the fuselage mold 30 and the upper surface of the upper mold 10 are coplanar, the lower end of the large diameter portion 11 of the upper mold 10 and the first inner circumferential diameter portion of the fuselage mold 30 A clearance is formed in the axial direction between the lower end of the 31. The length in the axial direction of the gap is G (L0 = L1 + G). The magnitude | size of G exceeds the shrinkage amount of the height direction (sliding direction of the upper mold 10) in the cooling process of the molded object (optical element) after shaping | molding.

That is, the molding mold of this embodiment is designed so that when the molded body is contracted in the cooling process, the upper mold can be lowered while slidingly guided by the fuselage mold. The following movement of the upper mold may be caused by adhesion and self weight with the molded body. Thereby, the surface shape precision of a molded object can be maintained high. Moreover, in order to enable such a following movement, it is preferable that the sliding mold of this invention does not have the site | part which contacts a fuselage mold in the process until it removes a molded object.

In addition, G can be made into length small enough (for example, 1/10 or less) with respect to L1.

In the upper surface of the upper mold 10, when the upper mold 10 is accommodated in the fuselage mold 30, at least the outer peripheral edge part adjacent to the upper surface of the fuselage mold 30 is planarly processed. In addition, the upper surface of the fuselage mold 30 is similarly planarized at least the part adjacent to the upper surface of the upper mold 10 at least. Therefore, the upper mold 10 is inserted into the fuselage mold 30 from the upper opening, and the upper surface (outer edge portion) of the upper mold 10 and the upper surface of the fuselage mold 30 are flush with each other in a predetermined amount. Form.

The tilt of the upper mold 10 can be suppressed by making the upper surface of the upper mold 10 and the upper surface of the fuselage mold 30 coplanar at the time of press molding. In order to do this, the lower surface of the press load applying means 50 (abutment surface of the upper mold 10 and the fuselage mold 30) is a horizontal plane with high precision. Alternatively, a member having a smooth lower surface is positioned between the press load applying means 50 and the upper mold 10 (body mold 30).

In addition, when the upper mold is inserted into the fuselage mold until it is pressed and cut by pressing (the access of the upper mold and the lower mold stops and the molded body has a predetermined thickness), the upper mold upper surface and the fuselage mold upper surface are flush with each other. As a result, the thickness precision of the molded body can be controlled with good reproducibility. Furthermore, when volume shrinkage of the molded body occurs in the cooling step after pressurization, the upper mold can thereby lower the inside of the fuselage mold to maintain close contact with the molded body.

Moreover, the ventilation mold 34 which penetrates the fuselage mold 30 in the thickness direction is provided in the fuselage mold 30 in the vicinity of the said clearance gap G, and the upper and lower molding surfaces 13 and 24. As shown in FIG.

[Mold Press Molding Mold (Second Embodiment)]

Next, the mold press molding mold which concerns on 2nd Embodiment of this invention is demonstrated with reference to FIG. However, about the structure common to 1st Embodiment, the same code | symbol as 1st Embodiment is attached | subjected and description of 1st Embodiment is used.

3 is a cross-sectional view of a mold press molding mold according to a second embodiment of the present invention.

The upper mold 10 of the molding mold shown in the drawing has an intermediate diameter between the large diameter portion 11 and the small diameter portion 12 that is smaller in diameter than the large diameter portion 11 and larger in diameter than the small diameter portion 12. An inner circumferential middle diameter portion 35 having a portion 14 and which can accommodate the middle diameter portion 14 between the first inner circumferential large diameter portion 31 and the inner circumferential small diameter portion 32 has a portion 14. ) Is different from the molding mold of the first embodiment. Here, the gap between the intermediate diameter portion 14 and the inner circumferential intermediate diameter portion 35 is C11, the length in the axial direction of the intermediate diameter portion 14 is L11, and the diameter of the intermediate diameter portion 14 is D11. In addition, the gap G is also formed in two places of G1 and G2.

When the clearance C11 is 10 micrometers or less in the said molding mold, the sliding guide length L is set to (L1 + L11) or (L1 + L11 + L2), and the said (1) formula (2) ) Can be applied. In this way, the sliding length L is largely secured in the allowable range, and the upper mold 10 can be prevented from falling down.

As described above, the molding mold according to the above embodiment does not cause damage to the mold due to the shape of the upper mold 10 (sliding mold), the lower mold 20 (stop mold), and the fuselage mold 30, Furthermore, it is possible to make molding in which thickness precision and surface precision are kept high. In particular, even in a molding mold having a small molding surface used for molding an optical element having a small diameter, both durability and precision can be obtained by selecting the size of the sliding portion that affects the eccentricity precision according to the required precision.

That is, in the above embodiment, since the tilt is not substantially generated between the lower mold 20 (the stationary mold) and the fuselage mold 30, the tilt that may occur during molding is the upper mold 10 (sliding mold). The upper mold 10 needs sliding between the fuselage mold 30, and it is impossible to completely eliminate the tilt between the fuselage mold 30, but the above-described embodiment has its sliding guide length. Is selected most advantageously within a range of acceptable molding mold dimensions to ensure the necessary capability of the optical element to be molded.

[Method of Manufacturing Optical Device]

Next, the manufacturing method of the optical element using the molding mold of FIG. 1 is demonstrated with reference to FIG.

4 is an explanatory diagram showing a method for manufacturing the optical element according to the embodiment of the present invention.

First, in a state where the lower mold 20 is taken out of the fuselage mold 30, a molding material 40 (glass preform, etc.) is supplied onto the molding surface 24 of the lower mold 20 (Fig. 4 (a)). ). This can be done by an automatic feeder with a suction pad (not shown). The molded material may be supplied at room temperature or may be supplied after heating to a predetermined temperature.

The lower mold 20 is inserted from the lower side of the fuselage mold 30 (FIG. 4B) so that the upper surface of the flange portion 22 of the lower mold 20 abuts against the lower surface of the fuselage mold 30. . In this state, the entire molding mold is placed on the horizontal mounting table. When the lower mold 20 is inserted from the lower side of the fuselage mold 30, the upper surface of the upper mold 10 protrudes upward from the upper face of the fuselage mold 30 by the thickness of the molding material 40. (FIG. 4C).

The molding mold in which the molding material 40 is accommodated is heated by heating means to a temperature range suitable for press molding. This is a temperature at which the glass material corresponds to a viscosity of 106 to 109 dPa · s, for example. In this state, the molding mold is placed on the lower side of the press load applying means 50 while being placed on a horizontal mounting table. That is, the press load applying means 50 abuts on the upper mold 10 to apply a load by pressurization of an air cylinder or the like. Since the molding material 40 is soft enough, when the upper mold 10 is pushed down and the lower surface of the press load applying means 50 contacts the upper surface of the fuselage mold 30, The descent stops. The sliding guide length L of the upper mold 10 is set so that necessary eccentricity precision is secured. That is, let it be length exceeding half of the axial length S of the fuselage mold 30. FIG. Here, the thickness of the molding material once at the press molding temperature is determined with good reproducibility. At this time, since the upper surface of the upper mold 10 and the upper surface of the fuselage mold 30 form the same plane, the collapse (tilt) of the upper mold 10 to the fuselage mold 30 is suppressed (Fig. 4 ( d)).

Moreover, the fuselage mold 30 is crimped | bonded to the flange part 22 of the lower mold 20 by load application, and the mutual positional relationship of the lower mold 20 and the fuselage mold 30 is maintained correctly. As a result, the mutual position of the lower mold 20 and the fuselage mold 30 and the mutual position of the fuselage mold 30 and the upper mold 10 are determined by crimping between molds by applying a load, and the molding surface is determined. Tilt between (13, 24) is suppressed. In this case, it is assumed that the lower mold 20 is also pressed against the horizontal mounting table.

Then, the molding mold is cooled in the state which accommodated the molded object 40 (FIG. 4 (e)). In the cooling process, the molded body 40 in the molding mold is also cooled and the volume is contracted. When the close contact between the molded body 40 and the molding surfaces 13 and 24 of the upper and lower molds 10 and 20 is released, the surface precision is reduced. Since the deterioration deteriorates, the molded body 40 is cooled while maintaining close contact with the upper and lower molding surfaces 13 and 24. That is, as the molded body 40 shrinks, the upper mold 10 descends accordingly. Thereby, deterioration of the surface precision by shrinking the molded object 40 at the temperature more than a glass transition point during cooling can be prevented.

In order to be able to descend | hang like this, when the upper surface of the fuselage mold 30 and the upper mold 10 is made into the same plane, the large diameter part 11 of the upper mold 10, and the 1st of the fuselage mold 30 will be carried out. Between the inner peripheral diameter part 31, the dimension is set so that the clearance gap G may arise. A vent hole 34 is formed in the vicinity of the gap G of the fuselage mold 30 (see FIG. 1), so that the atmosphere gas of the gap G, which becomes smaller in volume, with the descending of the upper mold 10, can flow out. It is supposed to be.

After lowering the temperature to a predetermined temperature, such as near or below the transition point, the lower mold 20 is removed from the fuselage mold 30 (FIG. 4 (f)) to form the molding surface 24 of the lower mold 20. ), The molded body 40 (glass lens, etc.) is extracted (Fig. 4 (g)).

Industrial Applicability The present invention is applied to a mold press molding mold for molding optical elements such as glass lenses and a method for manufacturing optical elements. In particular, the eccentricity is very high, and it is useful for molding precision optical elements used in optical pickups, small-capacity imaging devices, and the like.

According to the present invention, there is provided an effect of providing a mold press molding mold and an optical device manufacturing method for forming an optical element such as a glass lens, in particular, an eccentric precision is very high, and an optical element used for an optical pickup, a miniature imager, or the like. Have

Claims (17)

A mold including a sliding mold and a stationary mold with forming surfaces facing each other, and a fuselage mold allowing the sliding mold and the stationary mold to be inserted from both ends, respectively, and sliding guide the sliding mold at least during press molding. In the press molding mold, The sliding mold includes a large diameter portion and a small diameter portion having a diameter smaller than that of the large diameter portion, and having the molding surface formed at a tip thereof. When the length in the axial direction of the large diameter part in the sliding mold is L1, and the length in the axial direction of the small diameter part in the sliding mold is L2, L1〉 L2 Is established, The stationary mold has a large diameter portion and a small diameter portion having a diameter smaller than that of the large diameter portion, and having the molding surface formed at a tip thereof, The fuselage mold includes a first inner circumferential portion that accommodates and slides the large diameter portion of the sliding mold, an inner circumferential small portion that receives the small diameter portion of the sliding mold, and a second inner circumferential portion that receives the large diameter portion of the stationary mold. and, When the sliding mold has a sliding clearance of 10 μm or less, the length in the axial direction of the portion slid to the fuselage mold is L, and the total length in the axial direction of the fuselage mold is S, L ≥ 0.5S Mold press forming mold, characterized in that is established. The method of claim 1, L = L1 A mold press molding mold is established. The method of claim 2, The stop mold includes a flange portion having a larger diameter than the large diameter portion, and when the large diameter portion of the stop mold is accommodated in the second inner circumferential large diameter portion of the fuselage mold, the flange portion of the stop mold contacts the fuselage mold. The mold press forming mold, characterized in that the mutual position of the stop mold and the fuselage mold is defined. The method of claim 2, When a predetermined amount of the sliding mold is inserted into the fuselage mold, a part of the sliding mold becomes coplanar with a part of the fuselage mold, and the sliding mold can be further inserted into the fuselage mold in excess of the predetermined amount. Mold press molding mold, characterized in that. The method of claim 3, wherein When a predetermined amount of the sliding mold is inserted into the fuselage mold, a part of the sliding mold becomes coplanar with a part of the fuselage mold, and the sliding mold can be further inserted into the fuselage mold in excess of the predetermined amount. Mold press molding mold, characterized in that. The method of claim 2, When the clearance gap between the large diameter part of the said sliding mold and the 1st inner peripheral diameter part of the said fuselage mold is C1, L1 ≥ C1 / sinθ (θ ≤ 3min) Mold press forming mold, characterized in that is established. The method of claim 3, wherein When the clearance gap between the large diameter part of the said sliding mold and the 1st inner peripheral diameter part of the said fuselage mold is C1, L1 ≥ C1 / sinθ (θ ≤ 3min) Mold press forming mold, characterized in that is established. The method of claim 4, wherein When the clearance gap between the large diameter part of the said sliding mold and the 1st inner peripheral diameter part of the said fuselage mold is C1, L1 ≥ C1 / sinθ (θ ≤ 3min) Mold press forming mold, characterized in that is established. The method of claim 5, When the gap between the large diameter portion of the sliding mold and the first inner large diameter portion of the fuselage mold is C1, L ≥ C1 / sinθ (θ ≤ 3min) Mold press forming mold, characterized in that is established. The method according to any one of claims 1 to 9, When the gap between the large diameter portion of the sliding mold and the first inner peripheral diameter portion of the fuselage mold is C1, and the clearance between the small diameter portion of the sliding mold and the inner diameter small diameter portion of the fuselage mold is C2, C1 <C2 Mold press forming mold, characterized in that is established. The method according to any one of claims 1 to 9, When the sliding mold is used as the upper mold and the stop mold as the lower mold, and the upper mold is inserted into the fuselage by a predetermined amount, the upper surface of the upper mold is flush with the upper surface of the fuselage mold. Mold press molding mold characterized in that it comprises. The method according to any one of claims 1 to 9, An inner diameter of the second inner circumferential diameter portion of the fuselage mold is smaller than an inner diameter of the first inner circumference diameter portion of the fuselage mold. The method according to any one of claims 1 to 9, When the diameter of the large diameter portion of the sliding mold is D1, the diameter of the small diameter portion of the sliding mold is D2, the diameter of the small diameter portion of the stop mold is D3, and the diameter of the large diameter portion of the stop mold is D4. , D1 ≥ 2 D2 D4 ≥ 2 D3 A mold press molding mold is established. A method for manufacturing an optical element which is press-molded in a state in which a molded material is softened, wherein the mold press molding mold according to any one of claims 1 to 9 is used. The method of claim 14, Supply the molding material into the molding mold, Press-molded by the molding mold in a state where the molding material is softened by heating, In the manufacturing method of the optical element which cools the obtained molded object, And the sliding mold moves in the fuselage mold in accordance with the shrinkage of the molded article during cooling and cooling of the molded article. The method of claim 15, And inserting the sliding mold into the fuselage mold at a predetermined pressure such that at least a portion of the sliding mold is flush with at least a portion of the fuselage mold while the molded material is softened by heating. Method for manufacturing an optical device characterized in that. A mold including a sliding mold and a stationary mold with forming surfaces facing each other, and a fuselage mold allowing the sliding mold and the stationary mold to be inserted from both ends, respectively, and sliding guide the sliding mold at least during press molding. In the manufacturing method of an optical element using a press molding mold, The sliding mold has a sliding gap of 10 μm or less, the length in the axial direction of the portion sliding guided to the fuselage mold is L, the sliding gap is C, When the allowable value of the mutual inclination angle of two optical functional surfaces of the optical element to be obtained is θ, L ≥ C / sinθ By selecting L and C satisfying the, the dimensions of the sliding mold and the fuselage mold is determined.

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