KR20060100937A - Mold press-forming apparatus, press head thereof and method of manufacturing optical device - Google Patents

Abstract

When pressing the press-molding mold 1, first, the mold body 4 is pressed against the supporting surface 23 (reference surface) of the flange 22 of the lower mold 2 by the first press head 11 to make contact therewith. In this way, the mold body 4 and the lower mold 2 are positioned with each other. While maintaining this positioning state, a load is applied to the upper mold 3 by the second press head 12, and the molding material W is press-molded. At the time of press molding of the molding material W, the mold body 4 and the lower mold 2 are fixed without tilting, and the first press head 11 which presses and contacts them is also fixed, and the first press head. The upper mold 3 is pressed without inclination by the second press head 12 guided by 11. Thereby, generation | occurrence | production of the relative inclination of the upper and lower molds 3 and 2 can be suppressed reliably, and the optical element which has high shape precision can be manufactured.

Description

Mold press forming apparatus, press head and manufacturing method of optical element {MOLD PRESS-FORMING APPARATUS, PRESS HEAD THEREOF AND METHOD OF MANUFACTURING OPTICAL DEVICE}

1 is a schematic plan view showing an embodiment of a mold press molding apparatus to which the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing a press molding mold used in the mold press molding apparatus of FIG. 1.

3 is a schematic configuration diagram showing the configuration of the press chamber of FIG. 1.

4A and 4B are explanatory views showing the structure and operation of the first press chamber of FIG.

FIG. 5: is explanatory drawing which showed the press head which concerns on this invention used by the 2nd press chamber of FIG.

6C are explanatory drawing which showed the operation | movement in the 2nd press chamber of FIG.

FIG. 7: is explanatory drawing which showed the modification of the press head of FIG.

8 is an explanatory diagram showing another example of a press-molding mold to which the present invention is applied.

The present invention provides a method of manufacturing an optical element for manufacturing an optical element without grinding and polishing a surface to be formed by press molding a molded material such as glass by a press molding mold that is precisely processed, and a mold press used for this. Press] relates to a molding apparatus. In more detail, it is related with the improvement of the press means (press head) for pressurizing the press molding mold in a mold press molding apparatus.

BACKGROUND OF THE INVENTION A method for manufacturing optical elements such as high precision aspherical lenses or the like by press molding is known. According to this manufacturing method, since the complicated aspheric polishing process which has been conventionally performed is omitted, it is possible to manufacture a large amount of inexpensive optical elements of the same shape.

In recent years, with the demand for a high pixel imaging optical system or a high NA (Numerical Aperture) pickup lens, the coaxiality of the first and second surfaces required for an optical element becomes increasingly strict. have. Therefore, in order to suppress the inclination (tilt) of the axis | shafts of the up-and-down mold in a shaping | molding mold, and to suppress the axial shift | shift (shift) of the up-and-down mold in the horizontal direction, the structure of a shaping | molding mold is improved. There is a limit to correspond only by this, and the improvement of the pressurization method and pressurization means of a shaping | molding mold is aimed at. In addition, an optical element having a high degree of difficulty in molding, such as a concave meniscus lens, a biconcave lens, or the like, has a good surface by a multi-stage press for changing the application of load over time. To get precision.

For example, Patent Document 1 (Japanese Patent Laid-Open No. H11-35333) discloses a manufacturing method and a manufacturing apparatus of a glass molded body. In this manufacturing method, the heat-softened shaped glass material is initially pressed with a molding mold to transfer the molding surface shape of the molding mold, and the molding mold and the molded glass are cooled at the beginning of the initial pressing or during the initial pressing. . Then, during the cooling, a pressure (secondary pressure) that is weaker than the initial pressure is applied to the molded glass, and the molded glass is taken out of the molded mold after the molded glass becomes below the glass transition point. Thereby, it is said that the glass optical element with high surface precision and the precision of center thickness can be shape | molded.

In addition, Patent Document 2 (Japanese Patent Laid-Open No. H5-31504) discloses a method for manufacturing a glass molded body and a manufacturing apparatus. In this manufacturing method, the shaping | molding mold which consists of the up-and-down mold and mold body in which to-be-molded glass was arrange | positioned is conveyed in order inside the some press chamber. That is, the upper mold is pressed until the pressure stroke in the first press chamber is limited by the mold body (sleeve) to almost determine the center thickness of the molded glass, and the upper mold in the second press chamber. By pressing the bay with a pressure bar, the generation of a sink mark after pressurization is prevented, and the glass molded object with high shape precision is obtained.

On the other hand, Patent Document 3 (Japanese Patent Laid-Open Publication No. H4-42338) discloses a method of preventing the eccentricity by matching the axis between the upper mold and the lower mold by forming pressing projections on the pressing surface of the upper mold.

In addition, Patent Document 4 (Japanese Patent Laid-Open Publication No. H2-28460) presses the upper mold from the upper side through the pressing plate, and at the time of pressing, the pressing plate is brought into contact with the upper surface of the guide mold to incline (tilt) the central axis on both sides of the lens. Disclosed is a method for suppressing axial misalignment (decenter).

According to Patent Document 1, the glass material is molded into the shape of the final product by the initial pressure, and the surface accuracy can be maintained and improved by the secondary pressure. By the way, after the upper and lower molds are approached by the initial pressing to form a glass material, and when the upper mold is pressed by the secondary press, the mold body that guides the upper and lower molds is within the range of horizontal clearance. In the horizontal direction in the free state. For this reason, the coaxiality of an up-and-down mold is damaged, and there exists a fault that it is difficult to ensure the eccentricity of a molded article.

Moreover, according to the manufacturing method of patent document 2, since the mold body is pressed strongly with a lower mold, pressurizing an upper mold by primary pressure, the coaxiality of an up-and-down mold is ensured at the stage of primary pressure. However, since only the upper mold is pressed at the stage of the secondary pressing, the mold body is free and there is a fear that the eccentricity accuracy is lowered.

Moreover, since the method of patent document 3 is a method of preventing eccentricity from occurring in accordance with the method of applying the load by a pressurizing means, a pressurizing means does not raise eccentricity precision. Therefore, it is difficult to manufacture an aspherical surface (both aspherical surfaces) with high precision by the method disclosed in Patent Document 3.

On the other hand, in the method of patent document 4, an eccentricity precision is obtained by making a pressure plate contact. However, if the pressure plate comes in contact with it, no load is applied even after pressing. Therefore, it cannot be used as a technique which raises the eccentricity precision in the case of performing a press in several steps.

SUMMARY OF THE INVENTION In view of the problems described above, an object of the present invention is to improve the pressing means for applying a load to a press-molding mold, whereby a mold press-molding apparatus and its press head capable of performing press molding without deteriorating eccentricity accuracy, and optical It is to provide a method for manufacturing a device.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the mold press molding apparatus of this invention comprises the 1st mold which has a shaping | molding surface, the 2nd mold which has a shaping surface arrange | positioned facing the said 1st mold, and the said 1st and 2nd mold. Pressing to press-mold the molding material disposed between the molding surfaces by relatively moving the mold body inserted into and inserted into the coaxial and the molding surfaces of the first and second molds in a direction approaching. Have the means. The pressurizing means includes a pressurizing contact means for positioning the mold body by pressing the mold body into contact with a positioning reference plane, and a load applying means for pressurizing the first mold while being guided by the pressurizing contact means. It is characterized by including. Relatively moving means that the first mold may move toward the second mold and the second mold may move toward the first mold.

Here, the reference surface is a surface such that when the surface of a part of the mold body abuts, the central axial direction of the mold body is parallel to the pressing operation direction of the pressing means.

Preferably, the reference surface is formed on the second mold. In this case, the mold body and the second mold are positioned with each other by pressing the mold body into contact with the reference surface by the pressure contact means.

In the press molding apparatus of the present invention, at the time of press molding, at least the mold body is positioned with respect to the reference surface by the pressure contact means, and the load is applied to the first mold by the load applying means while maintaining the positioning state. To press the molding material. Therefore, when the molded material is pressed, the mold body is fixed while being positioned, so that no harmful effects such as the mold body inclining with respect to the moving direction of the upper and lower molds (that is, the pressing operation direction of the pressing means) do not occur. Thereby, deterioration of the eccentricity precision of a molded article can be prevented.

Here, the pressure contact means may be a cylindrical first press head, and the load application means may be a second press head inserted into and inserted into the first press head. In this case, according to the press operation of the said 2nd press head, it can be set as the structure provided with the biasing means which adds the said 1st press head to the press operation direction of the said 2nd press head. As the biasing means, an elastic member such as a coil spring disposed between the first and second press heads can be used.

Further, the first press head has a first pressing surface that is in contact with an axial end face of the side where the first mold is inserted in the mold body, and the second pressing portion is provided on the first pressing surface. The hole which allows an axial movement of a head can be formed.

The second press head is configured to include a second pressing surface that is substantially parallel to the first pressing surface of the first press head, and a large diameter portion that is in sliding contact with an inner circumferential surface of the first press head. It is preferable to form so that the said 2nd press surface of the said 2nd press head and the outer peripheral surface of the said large diameter part may orthogonally cross.

In this case, the axial length of the large diameter part of the second press head is defined as the lower end of the large diameter part in the second press head so that the second press head is accurately guided without being inclined by the first press head. It is preferable to make it longer than the axial length from a 2nd press surface to a said 2nd press surface.

Next, the second mold is generally provided with a flange having a large diameter formed at an axial end, and the flange can form the reference plane orthogonal to the pressing operation direction of the pressing means. . In this case, when the mold body is pressed by the first press head and in close contact with the reference surface, the upright direction of the mold body and the pressing operation direction of the pressing means may be made to coincide.

Meanwhile, the press head according to the present invention presses molding materials in a molding mold having first and second molds having opposite molding faces and mold bodies into which the first and second molds are coaxially inserted. In order to mold, it is applied to a mold press forming apparatus for pressing the molding mold. The press head includes pressurizing contact means for positioning the mold body by pressing and contacting the mold body to a positioning reference plane, and load applying means for pressurizing the first mold while being guided by the pressurizing contact means. It is characterized by having.

The pressurizing contact means is characterized in that the mold body and the second mold are positioned with each other by pressing the mold body into contact with the reference surface formed in the second mold.

Further, the pressure contact means has a cylindrical first press head, and the load applying means has a second press head inserted and inserted inside the first press head. The press head according to the present invention is further provided with a biasing means for adding the first press head in the pressing operation direction of the second press head in accordance with the pressing operation of the second press head. As the biasing means, an elastic member such as a coil spring disposed between the first and second press heads can be used.

On the other hand, the manufacturing method of the optical element according to the present invention, in the press-molding of the heat-softened molding material using the mold press molding apparatus of the above configuration, by the pressure contact means to the mold body to the reference surface And a load application step of applying a load to the first mold by the load application means in a pressurized contact state.

Here, the load application step is preferably carried out while at least cooling the molding material.

Moreover, when the said mold press molding apparatus is equipped with the said biasing means, when the load is applied by the said 2nd press head in the said load application process, the said 1st press head is applied by the biasing force of the said biasing means. It is desirable to increase the pressing force on the mold body.

Next, in the method of manufacturing the optical element according to the present invention, a first mold having a molding surface, a second mold having a molding surface disposed opposite to the first mold, and the first and second molds are coaxially formed. In a molding mold having a mold body inserted into and inserted into the mold, a supplying step of supplying a molding material between the molding surfaces, a heating step of heating and softening the molding material to a state suitable for press molding, and the state In the pressing, the molding mold includes a press process of press molding the molding material. The pressing step is performed by the first pressing step of pressurizing the molding material to a predetermined thickness in a predetermined temperature region, and by pressing means provided with a first press head and a second press head. And a second press process for further pressurizing the molded material at low temperature. In the second pressing step, the first press head, the mold body, and the second mold are positioned with each other by contacting the mold body with at least a portion of the second mold by the first press head. And a load application step of applying a load to the first mold by using the second press head guided by the first press head while maintaining the pressure contact step and the positioning state thereof. do.

Here, the second press process is preferably performed in a lower temperature range than the first press process.

In the load application step, it is preferable to increase the pressing force on the mold body of the first press head in accordance with the movement of the second press head.

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

(Mold Press Forming Equipment)

1 is a schematic plan view showing the whole of a rotatable mold press molding apparatus to which the present invention is applied, and FIG. 2 is a schematic cross-sectional view showing a press molding mold to be transferred. 3 is a schematic cross-sectional view of the press chamber in the mold press molding apparatus of FIG. 1.

The mold press molding apparatus P according to the present embodiment transfers a press molding mold containing a molding material (glass preform, etc.) to each processing chamber sequentially and performs a suitable treatment, thereby forming a desired molded body ( Glass optical elements).

As shown in FIG. 1, the mold press molding apparatus P has a circular planar shape. The mold press molding apparatus P is provided with the ejection and insertion chamber P1 and the many process chambers P2, P3, P4, P5, P6, P7, and P8 arrange | positioned side by side in the circumferential direction, and are always inert gas The press-molding mold containing the molding material is placed on the rotary table to sequentially pass through the interior of these processing chambers under the atmosphere of.

 The processing chambers P2 and P3 are the first and second heating chambers, and the processing chamber P4 is a crack chamber. The processing chamber P5 is a press chamber, and the processing chambers P6 and P7 are first and second slow cooling chambers. The processing chamber P8 is a quenching chamber. The press chamber P5 of this embodiment is comprised by the 1st press chamber P5 (1) and the 2nd press chamber P5 (2). These processing chambers P2-P8 are arrange | positioned at substantially equal intervals, and are temperature-controlled by the temperature suitable for each process. For this purpose, these processing chambers P2 to P8 are partitioned by shutters S1, S2, S3, S4, S5, S6, and S7.

Further, the first heating chamber P2, the second heating chamber P3, the crack chamber P4, the first slow cooling chamber P6, the second slow cooling chamber P7 and the quenching chamber P8 are formed of a molding material. It is for adjusting the temperature of the press molding mold accommodated and the press molding mold which accommodated the molding material or the obtained molded object.

The rotary table rotates intermittently at a predetermined time, and a molding mold supplied with a molding material therein passes through each of the processing chambers P1 to P8 in the insertion chamber in the ejection and insertion chamber P1. Is taken out as a molding mold in which the molded body is accommodated in the take-out part at ()). The cycle of intermittent rotation at this time becomes a molding cycle time. By using such a transfer mold press molding apparatus P, various processes required for press molding can be performed simultaneously, which is advantageous for shortening the real time (cycle time) required for molding one molded article. In addition, the transfer mold press-molding apparatus is not limited to the said rotary type, but also includes a linear movement type.

The present invention is suitable for the mold press forming apparatus and method as in the present embodiment, which transfers the press forming molds to the respective processing chambers and sequentially performs appropriate processing including heating, pressing, and cooling, but is not limited thereto. Of course. The present invention can also be applied to a molding apparatus and a method for performing a process including heating, pressing and cooling at the same position, for example, without transferring the press forming mold.

(Press molding mold)

As shown in FIG. 2, the press-molding mold 1 used in the present embodiment includes a lower mold 2 (the second mold) having the molding surface 2a and a molding disposed opposite the molding surface 2a. An upper mold 3 (first mold) having a face 3a, and a mold body 4 into which the lower mold 2 and the upper mold 3 are coaxially inserted and fitted. The mold body 4 is cylindrical in shape, and the hollow portion has a small diameter portion 41 at a substantially central portion in the vertical direction. Above and below the small diameter portion 41, an upper large diameter portion 42 and a lower large diameter portion 43 having a larger diameter are formed.

The lower mold 2 is provided with the cylindrical lower mold main body 21 and the large diameter circular flange 22 integrally formed coaxially with this lower end. The molding surface 2a is formed in the upper end surface of the lower mold main body 21. The lower mold body 21 has an outer diameter index that can be inserted into the lower large diameter portion 43 of the mold body 4. The circular flange 22 is formed with an annular bearing surface 23 (reference surface) of a corresponding size, to which the annular lower end surface 44 of the mold body 4 is pressed.

Here, the reference surface is such that when a part of the surface of the mold body 4 abuts, the central axial direction of the mold body 4 is parallel to the pressing operation direction of the pressing means (press head 10B) described later. Cotton. That is, in FIG. 2, the reference surface 23 is a surface which can contact the lower surface of the mold body 4 to make the mold body 4 upright, and is a surface orthogonal to the pressing operation direction of the pressing means.

The upper mold 3 is provided with the cylindrical upper mold main body 31 and the circular flange 32 of the large diameter integrally formed coaxially with this upper end. The molding surface 3a is formed in the lower surface of the upper mold main body 31. As shown in FIG. The upper mold body 31 has an outer diameter index that can be inserted into the small diameter portion 41 of the mold body 4. The flange 32 has an outer diameter index that can be inserted into the upper large diameter portion 42. The thickness of the flange 32 is thinner than the depth of the upper large diameter portion 42.

Here, the radial clearance of the mold body 4 and the lower mold 2 is 5 micrometers or less, and the clearance of the radial direction of the upper mold 3 and the mold body 4 is also the same. When the bottom surface 44 of the mold body 4 is in contact with the support surface 23 of the flange 22 of the lower mold 2, the circle of the upper mold 3 is reduced by the thickness of the glass material W. The shape top surface 33 is set to move to a position higher than the toroidal top surface 45 of the mold body 4. Moreover, the mold body 4 is formed so that the orthogonality of this lower surface 44 and the upper surface 45, and the inner peripheral surface of the hollow part may be high precision.

(Press room)

Next, as shown in FIG. 3, the press chamber P5 of the mold press molding apparatus P reflects the heat from the heating part 52 provided in the casing 51, and the heating part 52. As shown in FIG. A reflector 53 is provided. The press chamber P5 further includes a rotary table 55 as a conveying means for transferring the support table 54 supporting the press-molding mold 1 from the forming-mold mounting surface 54a at the tip, and at the time of press operation. The support bar 56 for supporting the rotating table 55 from the lower side is provided. The support rod 56 is controlled by the drive motor 59. The press chamber P5 further includes a pressurizing rod 57 for applying a predetermined load to the press-molding mold 1 on the support 54, a drive motor 58 for controlling the movement of the pressurizing rod 57, and a pressurizing rod. It is provided at the tip of 57 and is provided with the press head 10 which is a press means for pressurizing the press molding mold 1. 3 is a schematic block diagram which shows the cross-sectional structure of the press chamber P5 (2) in FIG.

Here, as the press head 10, the press head 10A shown in FIG. 4 mentioned later is attached to the 1st press chamber P5 (1). The press head 10B shown in FIG. 5, FIG. 6 mentioned later as the press head 10 is attached to 2nd press chamber P5 (2). The configuration other than the press head is basically the same.

(Press head)

4A and 4B are explanatory diagrams showing the press operation in the first press chamber P5 (1). As can be seen from this figure, in the first press chamber P5 (1), the press head 10A is connected to the tip of the pressurizing rod 57 as the press head 10. The press head 10A is a disk shape provided with the flat circular press surface 61 orthogonal to the direction (pressure operation direction) of the axis 57a of the press bar 57 which is a press direction.

FIG. 5 is a schematic cross-sectional view showing a press head provided in the second press chamber P5 (2), and FIGS. 6A to 6C are explanatory diagrams showing the press operation in the second press chamber P5 (2). to be. With reference to these drawings, the structure of the 2nd press head 10B arrange | positioned in 2nd press chamber P5 (2) is demonstrated.

The press head 10B (pressing means) is coaxial with the first press head 11 (pressing contact means) for pressing the mold body 4 toward the lower mold 2 and the inside of the first press head 11. The second press head 12 (load application means) which is inserted into and inserted into the upper mold 3 and presses only the upper mold 3, and the first press head 11 is connected to the second press head according to the pressing operation of the second press head 12. The coil spring 13 which is a biasing means added in the same direction as the pressurizing operation direction of 12 is provided.

The first press head 11 is made of a material having high heat resistance (for example, Si ₃ N ₄ or other ceramic), and exhibits a rough cylindrical shape. In this embodiment, the pressing operation direction of the press head 10B becomes the up-down direction (direction of the axis 57a of the pressing bar 57) which was shown, and the pressing surface (at the lower end of the 1st press head 11) 11a; 1st pressing surface is formed in the surface orthogonal to a pressing operation direction (direction of the axis 57a).

In the center part of the pressurizing surface 11a, the perforation 11b which allows the shanghai motion of the 2nd press head 12 is formed. The inner diameter of the perforation 11b is larger than the diameter of the tip 12b of the second press head 12 and is smaller than the diameter of the flange 32 of the upper mold 3. In addition, since the press surface 11a of the 1st press head 11 is an annular cross section larger than the outer diameter of the mold body 4, in the process of the press operation mentioned later, the press surface 11a is the upper mold 3 And the mold body 4 can be pressurized.

On the inner circumferential surface of the hollow part of the first press head 11, an annular first stepped surface 11c facing upward, an annular second stepped surface 11d facing upward, and an annular ring facing upward A third stepped surface 11e is formed.

The second press head 12 is made of a material having high heat resistance similarly to the first press head 11. The second press head 12 is inserted and inserted coaxially into the hollow portion of the first press head 11, and a cross section on its free end side, that is, a lower end surface has a circular shape of a size that presses only the upper mold 3. Pressing surface 12c (second pressing surface). The other end side of the second press head 12 is connected to the pressure bar 57. As the connection structure, the pressurizing rod 57 and the second press head 12 shown in the drawing are integrally formed, the two are connected by a screw coupling member or a fastening member, or a universal joint, or the like. Various connection structures can be selected, such as those connected via a joint.

In the middle portion of the second press head 12, large diameter portions 12a larger in diameter than both end sides are formed. After inserting the large diameter portion 12a of the second press head 12 inward (downward) from the third stepped surface 11e of the first press head 11, the first press head 11 is inserted therein. 11 f of fall prevention rings are fixed to the opening part of the upper end side, and it is integrated so that the 2nd press head 12 may not come out from the 1st press head 11.

The coil spring 13 is attached to the small diameter part 12b of the front end side (lower side) than the large diameter part 12a of the 2nd press head 12 so that this may be enclosed. The coil spring 13 is attached between the first stepped surface 11c of the first press head 11 and the lower stepped surface 12d of the large diameter portion 12a of the second press head 12. The coil spring 13 is made of a heat resistant spring material (ZrO ₂ ceramic [ceramics], austenitic stainless steel, Inconel alloy, Si ₃ N ₄ ceramic, etc.), and a predetermined spring constant ( For example, 3 kgf / mm).

The 1st press head 11 is urged downward with respect to the 2nd press head 12 by the coil spring 13 as a whole, and the lower surface of the fall prevention ring 11f of the 2nd press head 12 is carried out. It is maintained in contact with the upper end surface 12e of the large diameter part 12a. In this state, the pressing surface 11a of the first press head 11 protrudes slightly below the pressing surface 12c of the second press head 12. The amount of protrusion is, for example, about 2 mm.

In addition, when the first press head 11 and the second press head 12 are moved relative to each other in the axial direction, the second stepped surface 11d (position control unit) and the second press head of the first press head 11 are moved. When the lower step surface 12d of the large diameter part 12a of (12) abuts, the relative movement of both is regulated. That is, the maximum movement amount of both becomes S in the drawing. In this manner, the second stepped surface 11d functioning as the position regulating portion prevents the coil spring 13 from being excessively compressed and destroyed by the second press head 12 dropping excessively. However, in the normal press process, the lower stepped surface 12d of the large diameter portion 12a of the second press head 12 does not contact the second stepped surface 11d for position regulation. This is because the drop of the second press head 12 occurs when the pressing surface 12c of the second press head 12 protrudes by about 5 to 20 μm from the pressing surface 11a of the first press head 11. Because it is controlled to stop.

Moreover, as a preferable aspect, the clearance of the sliding part of the large diameter part 12a of the 2nd press head 12 and the inner peripheral surface of the hollow part of the 1st press head 11 is 5-15 micrometers. Moreover, it is preferable to suppress the fall (tilt) of the 2nd press head 12 in the said clearance by making these sliding movement lengths as long as possible.

For example, as shown in FIG. 7, the axis | shaft of the large diameter part 12a of the 2nd press head 12 so that it may become longer than the axial length L2 of the small diameter part 12b below the large diameter part 12a. By forming the directional length L1 relatively long, the upper mold 3 can be pressed more directly with the second press head 12. Of course, it is useful to maintain the verticality of the sliding movement part of the large diameter part 12a of the 2nd press head 12 and the press surface 12c with high precision.

(Manufacturing process of optical element by mold press forming apparatus)

Next, one Embodiment of the process of shape | molding an optical element using the mold press molding apparatus P of the said structure is demonstrated.

1) Glass material supply process

A preformed molding material such as a glass material W is prepared in a shape having a convex curved surface (in this embodiment, both convex curved surfaces), and the glass material W is formed by a conveyance arm with a suction pad. To return. In the state where the upper and lower molds 3 and 2 are spaced apart, the glass material W is released by releasing the adsorption of the glass material W at a positional accuracy within a predetermined range with respect to the molding surface 2a of the lower mold 2. ) Is distributed to the forming surface 2a of the lower mold 2. The return arm retracts immediately. In the mold press molding apparatus P, this step is performed in the disassembly and assembly section (not shown) provided outside the take-out and insertion chamber P1 or the outer circumferential circle in FIG.

2) Assembly process of press molding mold

In this step, the lower mold 2 is assembled into the mold body 4 into which the upper mold 3 has been inserted in advance. The radial clearance of the mold body 4 and the lower mold 2 is 5 micrometers or less, and the upper mold 3 and the mold body 4 are also the same clearance. When the bottom surface 44 of the mold body 4 abuts the supporting surface 23 of the lower mold flange 22, the top surface 33 of the upper mold 3 is moved by the thickness of the glass material W. It moves to a position higher than the top surface 45 of the mold body 4 (see FIG. 4A). This process can also be performed in the extraction / insertion chamber P1 or the above-described disassembly and assembly unit.

3) heating process

The press-molding mold 1 in which the glass material W is accommodated is sequentially heated to the first heating chamber P2, the second heating chamber P3, and the crack chamber P4, and the temperature is raised to increase the temperature. And press-molding mold 1 to a temperature suitable for press-molding.

For example, the 1st heating chamber P2 is maintained at the high temperature more than the press temperature of the glass material W, and heats the press molding mold 1 and the glass material W rapidly. After the press-molding mold 1 and the glass material W are stopped for a predetermined time in the first heating chamber P2, the rotary table 55 rotates to reach the second heating chamber P3. By heating in the second heating chamber P3, the press-molding mold 1 and the glass material W are further heated or cracked to approach the press temperature. Subsequently, the press-molding mold 1 and the glass material W are cracked in the crack chamber P4, and the glass viscosity is made the viscosity equivalent of 10 ⁶ to 10 ⁹ poises suitable for press molding, and the press chamber Transfer to (P5). Preferably, the glass material is at a temperature that results in a viscosity of 10 ⁶ to 10 ⁸ poise. The heating means is not particularly limited, such as a heater by resistance heating and a high frequency induction coil.

4) Press process

Press chamber P5 consists of 1st press chamber P5 (1) and 2nd press chamber P5 (2) as mentioned above. The first press chamber P5 (1) and the second press chamber P5 (2) are partitioned by a shutter S4, and each chamber is provided with a pressurizing means, so that each room temperature can be individually controlled. Consists of.

In the state where the press-molded mold 1 containing the glass material W heated at a temperature of 10 ⁶ to 10 ⁹ poise at a heating step is transferred to the first press chamber P5 (1), As shown in FIG. 4A, the upper mold 3 slightly protrudes from the top surface 45 of the mold body 4. In the first press chamber P5 (1), the pressing surface 61 at the tip presses the upper mold 3 using the press head 10A having a larger diameter than the mold body 4 (the load is For example, 30-200 kgf), as shown in FIG. 4B, the upper surface 45 of the mold body 4 and the upper surface 33 of the upper mold 3 are positioned on the same plane. At this time, the glass material (W) is deformed according to the drop of the upper mold (3), but the pressure is maintained for a predetermined time (for example for several tens of seconds) while applying a load in the state of Figure 4B. By the press in the said 1st press chamber P5 (1), it can shape | mold so that the thickness of the glass material W may become in the predetermined range with respect to the thickness of the press product to obtain.

Next, the press molding mold 1 is transferred to the second press chamber P5 (2), and is molded using another press head 10B as shown in FIGS. 6A to 6C. Further, the second press chamber P5 (2) has a temperature lower than that of the first press chamber P5 (1) (for example, a viscosity of the glass material in the molding mold becomes a temperature of 10 ⁹ to 10 ¹⁴ poises). Temperature).

FIG. 6A shows a state immediately before pressing the press-molding mold 1 with the press head 10B. The press head 10B is connected to the lower end of the pressurizing rod (drive shaft) 57 located above, and the press head 10b also continues to fall with the fall of the pressurizing rod 57, and eventually, as shown in FIG. 6B. Similarly, the pressing surface 11a of the first press head 11 is in contact with the upper surface 45 of the mold body 4. At this point, the first press head 11 substantially restricts further drop by the mold body 4. In addition, the pressing surface 11a of the first press head 11 may also be in contact with the upper surface 33 of the upper mold 3.

As the pressing rod 57 continues to descend, only the second press head 12 descends while the first press head 11 is stopped, as shown in FIG. 6C, to press the upper mold 3. At this time, since the coil spring 13 is gradually compressed in accordance with the drop (pressing operation) of the second press head 12, the first press head that has been in contact with the upper end surface 45 of the mold body 4 with a light load. 11 presses the mold body 4 by the spring force, and the pressing force increases with the amount of drop of the second press head 12.

In the present embodiment, since the pressing surface 12c of the second press head 12 is set to be located about 2 mm above the pressing surface 11a of the first press head 11, the second press head ( At the time when the pressing surface 12c of 12 is in contact with the upper mold 3, the coil spring 13 is compressed by 2 mm. If the spring constant is 3 kgf / mm, when the coil spring 13 is compressed by 2 mm, the first press head 11 presses the mold body 4 to 6 kgf.

As for the lower mold 2, the support surface 23 (reference surface) orthogonal to the press operation direction of the press head 10B is formed in the flange 22, and the mold body 4 is connected to the 1st press head 11 by the 1st press head 11. As shown in FIG. When pressurized, the bottom surface 44 of the mold body 4 comes into close contact with the supporting surface 23 of the lower mold 2. At this time, the orthogonality of the lower surface 44 and the upper surface 45 of the mold body 4 and the inner circumferential surface of the mold body 4 is formed with high precision, so that the upper mold 3 is pressed without being inclined. Therefore, generation | occurrence | production of the tilt of the molded article Wa (FIG. 6C) can be suppressed beforehand.

The drop of the second press head 12 is controlled so as to stop when the pressing surface protrudes by about 5 to 20 μm from the pressing surface 11a of the first press head 11. In the second press chamber P5 (2), the glass material W is cooled to a temperature corresponding to a state in which the viscosity exceeds 10 ¹³ poise while maintaining the state of FIG. .

By this cooling, the glass material W causes heat shrink, but while the mold body 4 is brought into close contact with the support surface 23 of the lower mold 2 by the first press head 11, the second press head ( Since the predetermined load (load larger than the self weight of the upper mold 3) is applied to the upper mold 3 by 12), the surface shape of the molded product Wa can be maintained with high accuracy. In particular, since the meniscus lens and both concave lenses having a concave surface have a large amount of heat shrinkage due to cooling, it is effective to apply a load by the second press head 12 during the cooling process.

When the press molding mold 1 and the molded product Wa are cooled to a predetermined temperature or less, the press head 10B is raised to release the pressing force on the press molding mold 1.

5) Cooling process

The press molding mold 1 which has finished the pressing process is sequentially transferred to the first slow cooling chamber P6 and the second slow cooling chamber P7 so that the molded body Wa is sufficiently lower than the transition temperature Tg. It cools until it becomes (for example, about Tg-50 degreeC). At this time, since the upper mold 3 follows the shrinkage of the glass due to its own weight, the contact between the molded body Wa and the molding surface 3a is maintained, so that good shape accuracy is obtained. Thereafter, the press-molding mold 1 is transferred to the quenching section P8 and quenched by the gas for cooling.

6) Mold disassembly process

The press-molding mold 1 returns to the take-out / insertion chamber P1, is conveyed from here to the disassembly and assembly section (not shown), disassembles the press-molding mold 1, takes out the molded body Wa, and new glass. Supply of the raw material W is performed. In other words, the press-molded mold 1 containing the molded body Wa is placed on the disassembly table (not shown) by the robot and positioned by gripping the circumference. The disassembly table is lowered vertically to separate the upper and lower molds 3 and 2. In the present embodiment, the processing chambers P2 to P7 are in an inert gas atmosphere, and the ejection / insertion chamber P1 is opened to the air at the time of ejection and insertion, so that the oxidation prevention of the press-molding mold 1 is considered. It is preferable to perform atmospheric opening in the extraction / insertion chamber P1 at 250 degrees C or less.

7) Blowing process of the molded body

The conveying arm is inserted between the upper and lower molds, and the molded product Wa is sucked out by the suction pad at the tip. Thereafter, the above steps are repeated.

(Effect of this embodiment)

As described above, according to the mold press-molding apparatus P according to the present embodiment, when the upper mold 3 is pressed by the second press head 10B, the first press head 11 is the mold body 4. ) Is pressed so as to stand up against the support surface 23 of the lower mold 2. Therefore, by ensuring the parallelism between the upper and lower end surfaces 44 and 45 of the mold body 4 and the supporting surface 23 of the lower mold flange 22 in advance, the mold body 4 and the lower mold 2 can be secured. The relative slope of can be reliably suppressed.

In addition, the pressing surface 12c of the second press head 12 is formed to be substantially parallel to the pressing surface 11a of the first press head 11, and also the pressing surface 12c of the second press head 12. ) Is formed to be orthogonal to the outer circumferential surface of the large diameter portion 12a of the second press head 12. Therefore, with the drop of the second press head 12, the first press head 11 can press the mold body 4 directly (parallel to the falling direction of the second press head 12), The second press head 12 can press the upper mold 2 directly. In addition, the press surface 12c orthogonal to the outer peripheral surface of the large diameter part 12a means that it is orthogonal to the press surface 12c when the outer peripheral surface of the large diameter part 12a is extended downwardly as it is.

As described above, since the relative inclination between the mold body 4 and the upper mold 2 can be suppressed, the tilt occurring between the upper and lower surfaces of the molded article (optical lens) can be reliably suppressed.

In other words, in this embodiment, the fully softened glass material W is pressed to a predetermined thickness with good eccentricity in the first pressing step. Furthermore, this is cooled to a predetermined temperature range, and an appropriate load is applied to the shape of the formed surface of the glass material W affected by the heat shrink by cooling to maintain surface accuracy. The temperature range is in the range of the transition temperature Tg to the distortion point Ts, and the thickness change amount due to pressurization is 5 to 20 µm.

Further, in the second press process, first, the pressure contact process is performed, and the lower mold 2 and the mold body 4 are pressed to contact each other to fix their relative positions, and as a result, the mold body 4 is pressed and contacted. The position of the first press head 11 is also fixed. Therefore, the position of the 2nd press head 12 guided by the 1st press head 11 is also defined indirectly. As a result, the agreement between the axes of the upper and lower molding surfaces is obtained.

Therefore, the present embodiment can be applied not only to the formation of biconvex lenses and convex meniscus lenses, but also to the formation of concave meniscus lenses and both concave lenses. A lens with high precision with a good planar shape can be formed.

(Other Embodiments)

The mold press molding apparatus P is a device that sequentially transfers the press molding mold 1 to each processing chamber by rotational transfer. However, the press head according to the present invention is a press apparatus of a linear transfer method or a molding mold. The present invention can also be applied to a single press apparatus which press-molizes in one processing chamber without transferring.

In addition, since the arrangement | positioning structure of each process chamber etc. of the said mold press molding apparatus is made into a heating process and a cooling process which are necessary according to the composition of a molding material and the shape of a molded object, it can change suitably.

For example, in the said embodiment, although two press chambers were provided and each pressed using the different press head, it can also press with respect to a molding mold using only the press head of this invention as one press chamber of this invention. . In this case, it is preferable to appropriately control the temperature in the press chamber. In addition, it is also possible to change the number of heating chambers including a crack chamber into four or three cooling chambers.

In addition, in order to further increase the production efficiency of the process, the heating chamber, the press chamber, and the cooling chamber may be installed in the same number of consecutive years, and a plurality of types of moldings requiring different temperature conditions and different pressurization conditions may be performed simultaneously. .

Moreover, in each process chamber, when processes, such as heating, pressurization, and cooling, are performed, two or more shaping | molding molds may be arrange | positioned and the same process may be performed simultaneously to these. In this case, it is preferable to provide two or more pressing means in correspondence with the number of molding molds in a press chamber.

Moreover, this invention is applicable also when using the press molding mold 1A of the structure shown in FIG. The basic structure of the press-molded mold 1A shown in this figure is the same as that of the press-molded mold 1 described above, and includes a lower mold 2A, an upper mold 3A, and a mold body 4A. The difference from the press-molding mold 1 described above is that the lower mold flange 22 is fitted into the mold body 4A, and the lower surface 44 of the mold body 4A is placed on the mounting surface of the support 56 ( 56a).

In this case, the reference surface for fixing the mold body 4A in the positioning state at the time of pressing is the mounting surface 56a. The placing surface 56a is a surface orthogonal to the pressing operation direction of the press head 10B. At the time of press, the mold body 4A is pressed by the 1st press head 11 of the press head 10B, and the lower end surface 44 is pressed by the mounting surface 56a, and is in contact with it. Therefore, if the orthogonality of the lower end surface 44 of the mold body 4A and the inner circumferential surface of the hollow part is precisely defined, the inclination of the mold body 4A can be prevented, and the molding material W in that state. Can be pressed.

In the above embodiment, the positioning reference planes 23 and 56a and the lower end 44 of the mold bodies 4 and 4A in contact with the reference plane are both flat surfaces, but the reference planes to which the present invention is applied It is not limited to a flat surface. For example, the bottom surface of the mold body is a convex surface having an inclined surface, the reference surface is a concave surface inclined equally, and both are pressed and contacted so that the central axial direction of the mold body is pressed by the pressing means. What is necessary is just a surface parallel to a direction.

According to the present invention, when pressing a molding material, first, the mold body is positioned and fixed, or the mold body and the second mold are fixed in a state where they are positioned with each other, and this state is maintained in the first mold. A press load is applied to the molding material. Therefore, when the molded material is press-molded, the mold body is fixed without being inclined, so that relative inclination occurring between the first and second molds can be prevented, and an optical element having high shape precision can be manufactured.

In particular, in the case where the molded body is pressed by contact with the second mold and a load is applied to the first mold in a state where their relative positions are fixed, these press contact surfaces are formed with high precision, and If the orthogonality of the pressure contact surface of the mold body and the inner circumferential surface of the mold body for guiding the upper mold is precisely formed, the upper mold can be pressed without inclination, so that the eccentricity of the molded article can be improved.

In the manufacturing method of the optical element of the present invention, the pressing step is performed in two steps including the first and second pressing steps, and in the second pressing step, the mold body is first formed by the pressure contact step. The molded materials are pressed by applying pressure to the first mold in the load application step, while defining the position of each other by pressure contact with each other. Therefore, an optical element having a high shape difficulty, for example, a concave meniscus lens or both concave lenses, can be manufactured with high shape accuracy.

Claims (15)

A first mold having a molding surface, A second mold having a molding surface opposed to the first mold, A mold body into which these first and second molds are coaxially inserted and fitted; It has pressing means for press-molding the molding material arrange | positioned between these molding surfaces by moving relatively between the said molding surfaces of the said 1st and 2nd mold in the direction which adjoins, The pressing means, Pressure contact means for positioning the mold body by pressing the mold body into contact with the positioning reference surface; And a load application means for pressurizing the first mold while being guided by the pressure contact means. The method of claim 1, The reference surface is formed in the second mold, And said mold body is pressed against said reference surface by said pressure contact means so that these mold bodies and said second mold are positioned with each other. The method of claim 2, The pressure contact means has a cylindrical first press head, The load applying means has a second press head inserted and inserted inside the first press head, And the pressing means further comprises a biasing means for adding the first press head in the pressing operation direction of the second press head in accordance with the pressing operation of the second press head. The method of claim 3, wherein The said 1st press head has the 1st press surface which can abut in the axial end surface of the side in which the said 1st mold in the said mold body is inserted, A mold press forming apparatus, wherein the first pressing surface is formed with a hole allowing the axial movement of the second press head. The method of claim 1, The pressing contact means has a first pressing surface that is in contact with an axial cross section of the side where the first mold is inserted in the mold body, The load applying means includes a second pressing surface substantially parallel to the first pressing surface of the pressing contact means, and a large diameter portion which is capable of sliding contact with the inner circumferential surface of the pressing contact means, A mold press forming apparatus, characterized in that the first pressing surface of the load applying means and the outer circumferential surface of the large diameter portion are orthogonal to each other. The method of claim 5, The axial length of the said large diameter part of the said load application means is longer than the axial length from the lower end of the said large diameter part to the said 2nd press surface in the said load application means. The method of claim 1, The second mold has a large diameter flange formed at an axial end thereof, In the flange, the reference surface orthogonal to the pressing operation direction of the pressing means is formed, And wherein the mold body is pressed by the pressure contact means and in close contact with the reference surface, the upright direction of the mold body coincides with the pressing operation direction of the pressing means. Pressing the molding mold in order to press-mold the molding material in the molding mold having the first and second molds having the molding faces facing each other and the mold body into which the first and second molds are coaxially inserted. As a press head of a mold press forming apparatus, Pressure contact means for positioning the mold body by pressing the mold body into contact with the positioning reference surface; And a load applying means for pressing the first mold while being guided by the pressure contact means. The method of claim 8, The pressure contact means has a cylindrical first press head, The load applying means has a second press head inserted and inserted inside the first press head, The press head for mold press molding apparatus further includes a pressurizing means for adding the first press head in the pressing operation direction of the second press head in accordance with the pressing operation of the second press head. Press head for molding machine. A method of manufacturing an optical element by press molding a heat-softened molding material using the mold press molding apparatus according to claim 1 to obtain an optical element, A pressure contact process of pressing the mold body against the reference surface by the pressure contact means for positioning the mold body; And a load application step of applying a load to the first mold by the load application means in a state in which the mold body is pressed and in contact with the reference surface. The method of claim 10, The load application process is performed at least while cooling the molded material. A method for manufacturing an optical element, wherein the molded material is heat-softened using the mold press molding apparatus according to claim 3 to obtain an optical element. And a load applying step of applying a load to the first mold by the load applying means in a state in which the mold body is pressed into contact with the reference surface by the pressure contact means. When the load is applied by the second press head in the load application step, the pressing force of the first press head against the mold body is increased by the biasing force of the biasing means. . In a molding mold having a first mold having a molding surface, a second mold having a molding surface opposed to the first mold, and a mold body in which these first and second molds are coaxially inserted and fitted into the mold. A supplying step of supplying a molding material between the molding surfaces; A heating step of heating and softening the molded material to a state suitable for press molding; And a press process of press molding the molding material by pressing the molding mold in a state in which the molding material is heated and softened. The pressing step may further include pressing the molded material by a first pressing step for pressing the molded material to a predetermined thickness in a predetermined temperature region and pressing means having a first press head and a second press head. A second press process for pressurizing, In the second pressing step, the first press head, the mold body, and the second mold are positioned with each other by contacting the mold body with at least a portion of the second mold by the first press head. And a load application step of applying a load to the first mold by using the second press head guided by the first press head while maintaining the pressure contact step and the positioning state thereof. The manufacturing method of an optical element. The method of claim 13, The second pressing process, the method of manufacturing an optical element, characterized in that performed in a lower temperature range than the first pressing process. The method of claim 14, In the load application step, the pressing force against the mold body of the first press head is increased in accordance with the movement of the second press head.

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