JP2005104807A - Apparatus and method for forming optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for forming an optical element which facilitate positioning of upper and lower molds performed by using a drum mold without generating wear and enable the optical element to be highly accurately formed. <P>SOLUTION: In the forming apparatus 1, an optical glass base material 10 is heated, softened and formed into the optical element. The forming apparatus 1 is equipped with a couple of molds 2, 3 for pressing a heated and softened optical glass base material 10, the drum mold 4 having a reference surface 17 for determining mutual positions of the mold 2, 3, a receiving member 5 for supporting the drum mold 4, and pressing members 21, 22 for pressing the outer peripheral parts of the couple of molds 2, 3 in the direction intersecting with the optical axis from the same direction so as to position the couple of molds 2, 3 by causing the molds 2, 3 to abut on the reference surface 17 of the drum mold 4 supported by the receiving member 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molding apparatus and a molding method for molding optical elements such as lenses and prisms by heating and pressing an optical glass material.

  In the molding of optical elements, the upper and lower molds facing each other are inserted into a body mold, and the upper and lower molds are slid in the body mold to perform press molding. A conventional molding apparatus having such a structure is disclosed in JP-A-7-2535.

In this conventional molding apparatus, an upper die and a lower die sandwiching an optical glass material are slidably inserted into a barrel die so that the upper and lower die optical axes are aligned, and in this state, a pair of upper and lower press heads are aligned. It is structured to be installed in between. In addition to this, a cylinder-type fixing head for holding and fixing the cylinder mold is arranged. In a molding apparatus having such a structure, when the temperature reaches a temperature at which the optical glass material can be deformed by heating, the barrel mold fixing head sandwiches the barrel mold to regulate the position of the barrel mold, and then moves the upper mold. The optical glass material is pressed and deformed to mold the optical element.
Japanese Patent Laid-Open No. 7-2535

  In the above-described conventional molding apparatus, the inner surface of the barrel mold and the outer surfaces of the upper and lower molds are in contact with each other, and the upper and lower molds (upper mold) slide in the barrel mold in this contact state. That is, the upper and lower molds are sandwiched between the upper and lower molds so that the clearance is zero, and since both the upper and lower molds are formed of a rigid body, the contact portions of these are inevitably worn. When this wear occurs, the roundness is lost, so it becomes difficult to align the optical axes of the upper and lower molds, and the molds must be replaced.

  In order to prevent such wear, a clearance of about 1 to 3 μm is provided between the upper and lower molds and the body mold, but in this case, the direction deviates perpendicularly to the pressing direction of molding. Shift deviation and tilt deviation that deviates in the direction inclined with respect to the press direction are likely to occur between the upper and lower molds. When these deviations occur, the accuracy of the optical element to be molded decreases.

  In addition, it is structurally difficult to prevent such shift and tilt shifts with respect to a clearance of about 1 to 3 μm. A new problem arises that makes the entire system complicated and difficult to control.

  The present invention has been made in consideration of such conventional problems, and the positioning of the upper and lower molds by the barrel mold can be easily performed without causing wear, and the optical element can be molded with high performance. An object of the present invention is to provide an optical element molding apparatus and molding method that can be performed with high accuracy.

  An optical element molding apparatus according to claim 1 is a molding apparatus that forms an optical element by heating and softening an optical glass material, and a pair of molding dies for pressing the heat-softened optical glass material, and molding In order to position the barrel mold having a reference surface for positioning between the molds, a receiving member that supports the barrel mold, and the pair of molding dies in contact with the reference surface of the barrel mold supported by the receiving member, A pressing member that presses the outer peripheral portions of the pair of molds in the direction intersecting the optical axis from the same direction.

  In the first aspect of the present invention, the pressing member presses the pair of molding dies in the direction intersecting the optical axis from the same direction in a state where the barrel mold is supported by the receiving member, so Contact the mold. By this contact, the pair of molding dies are in a mutual positioning state with reference to the reference surface, and the optical element is molded in this positioning state.

  In such a first aspect of the invention, the pair of molds are positioned in contact with the reference surface of the body mold from the direction intersecting the optical axis, so that no shift deviation or tilt deviation occurs, and simple With the structure, the pair of molds can be positioned with high accuracy, and the optical element can be molded with high accuracy.

  A second aspect of the present invention is the optical element molding apparatus according to the first aspect, wherein the body mold has a cylindrical shape, and an opening is provided on the outer peripheral surface thereof so that the pressing member can advance and retract. It is characterized by.

  According to the second aspect of the present invention, since the pressing member advances and retreats through the opening formed in the cylindrical body mold, the pressing member can accurately advance and retract with respect to the body mold. Thereby, the press by a press member can be performed reliably.

  A third aspect of the present invention is the optical element molding apparatus according to the first or second aspect, wherein the pressing member includes a first pressing member that presses one molding die and a first pressing member that presses the other molding die. The second pressing member is disposed substantially opposite to the receiving member.

  In the invention of claim 3, since the pressing member is provided for each of the pair of molds, the pressing force of the two pressing members can be adjusted to be different, and the pair of molds abut against the reference surface. The state can be controlled satisfactorily.

  Further, in the invention of claim 3, since the second pressing member is arranged substantially opposite to the receiving member, the position can be regulated by supporting the body mold on the receiving member by the pressing by the second pressing member. The body mold is in a stable state. For this reason, positioning by making a shaping | molding die contact | abut to the reference surface of a trunk die can be performed with high precision.

  According to a fourth aspect of the present invention, there is provided a method for molding an optical element, wherein the optical glass material is heated and softened to form an optical element. In a state in which the molding die and the optical glass material are inserted, and the position of the barrel die is restricted, the outer peripheral portions of the pair of molding dies are pressed in the direction intersecting the optical axis from the same direction. The method includes a positioning step of positioning a molding die in contact with a reference surface of a body mold, and a step of molding the optical glass material with a pair of molding dies.

  After inserting the pair of molds holding the optical glass material into the barrel mold, the pair of molds are pressed in the direction intersecting the optical axis from the same direction, thereby forming the pair of molds on the reference surface of the barrel mold. A pair of molds are brought into a mutual positioning state by abutting. In such positioning by contact with the reference surface, no shift shift or tilt shift occurs, and the pair of molds can be positioned with high accuracy by a simple operation.

  According to a fifth aspect of the present invention, there is provided the optical element molding method according to the fourth aspect, wherein in the positioning step, after the one mold is brought into contact with the reference surface of the cylinder mold, the other mold is moved to the cylinder. It is made to contact | abut to the reference plane of a type | mold.

  In the invention of claim 5, since the positioning is performed by bringing the molding die into contact with the reference surface of the barrel die in a stepwise manner, excessive pressing force does not act on the barrel die, and the position of the barrel die is adjusted. It is possible to reliably regulate, and the positioning of the mold can be performed with high accuracy.

  According to the optical element molding apparatus of the present invention, since the pair of molding dies are positioned in contact with the reference surface of the barrel mold from the direction intersecting the optical axis, shift deviation and tilt deviation occur with a simple structure. This can be prevented, and the pair of molds can be positioned with high accuracy.

  According to the method for molding an optical element of the present invention, a pair of molding dies are brought into contact with the reference surface of the barrel mold by pressing the pair of molding dies in the direction intersecting the optical axis from the same direction. Since the molds are in the mutual positioning state, no shift deviation or tilt deviation occurs, and the pair of molding dies can be positioned with high accuracy by a simple operation.

  Hereinafter, the present invention will be specifically described with reference to embodiments shown in the drawings. FIG. 1 shows an optical element molding apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 show a positioning operation of a mold.

  As shown in FIG. 1, the molding apparatus 1 supports an upper mold 2 and a lower mold 3 as a pair of molding molds, a trunk mold 4 in which these molds 2 and 3 are inserted facing each other, and a trunk mold 4. Receiving member 5 and a pressing member 6 provided corresponding to the pair of molds. The optical glass material 10 to be molded is subjected to press molding in a state of being sandwiched between the lower mold 3 and the upper mold 2.

  The body 4 having the upper mold 2 and the lower mold 3 inserted therein is molded on the optical glass material 10 while being placed on the lower mold heater plate 7. The lower die heater plate 7 is attached to the upper surface of the lower die heater 8 supported by a lower shaft (not shown). On the other hand, the upper mold heater plate 11 is disposed so as to contact the upper mold 2. The upper heater plate 11 is attached to the lower surface of the upper heater 12 attached to the upper shaft 13. The upper shaft 13 applies a pressing force along the arrow B direction parallel to the optical axis, whereby the upper mold 2 moves in the lower mold 3 direction, and the optical glass material 10 is press-molded.

  In this embodiment, the upper shaft 13 is provided with a shift free mechanism 14. The shift-free mechanism 14 has a structure in which a small-diameter steel ball 15 is sandwiched between a pair of parallel plates 14a and 14b, and a shift direction perpendicular to the optical axis while the pair of parallel plates 14a and 14b maintains a parallel state. It can move in the direction of arrow A. Further, the upper shaft 13 is attached to one parallel plate 14a, and the other parallel plate 14b is attached to the main body of the molding apparatus, so that the upper shaft 13 moves in the shift direction together with the one parallel plate 14a. Can do. Therefore, the upper mold heater 12 and the upper mold heater plate 11 attached to the upper shaft 13 are movable in the shift direction A. By providing such a shift-free mechanism 14, even if the upper mold 2 shifts as will be described later, the upper shaft 13, the upper mold heater 12, and the upper mold heater plate 11 move in the same direction following the shift. Therefore, the pressing force can be reliably applied to the upper mold 2.

  The body mold 4 is formed into a cylindrical shape such as a cylinder, and the pair of upper and lower molds 2 and 3 are formed into a cylindrical shape having substantially the same outer shape as the body mold 4, and the upper and lower molds 2 and 3 are inserted into the body mold 4. Is done. The inner surface of the cylindrical body mold 4 is a reference surface 17 for positioning the pair of upper and lower molds 2 and 3. The positioning of the upper and lower molds 2 and 3 is performed by the upper and lower molds 2 and 3 coming into contact with the reference surface 17 and following the reference surface 17.

  Further, on the side opposite to the reference surface 17 in the body mold 4, a vertically long slit-shaped opening 18 for advancing and retracting a pressing member 6 described later is formed. As the pressing member 6 advances and retreats through the opening 18 in this way, the pressing member 6 can accurately advance and retreat with respect to the body mold 4, so that the pressing member 6 reliably presses the upper and lower molds 2 and 3. Can be done.

  The receiving member 5 that supports the body mold 4 is fixed on the lower heater plate 7 so as to be positioned outside the body mold 4. The receiving member 5 has a sharp support protrusion 5 a that contacts the outer surface of the trunk mold 4, and the support protrusion 5 a contacts the outer surface of the trunk mold 4 on the reference surface 17 side to support the trunk mold 4. Is going. The contact position of the support protrusion 5a on the body mold 4 is set as shown in FIG.

  The pressing member 6 presses the upper and lower molds 2 and 3 and is disposed so as to face the opening 18 of the trunk mold 4. In this embodiment, the pressing member 6 is composed of two members, a lower first pressing member 21 and an upper second pressing member 22. The first pressing member 21 is disposed so as to correspond to the outer peripheral portion of the lower mold 3, and the second pressing member 22 is disposed so as to correspond to the outer peripheral portion of the upper mold 2. Further, since the pressing members 21 and 22 are disposed so as to face the opening 18 of the trunk mold 4, the upper and lower molds 2 and 3 are pressed from the same direction.

  These pressure members 21 and 22 use fluid pressure cylinders, and piston rods 21a and 22a advance and retreat with respect to the opening 18 of the barrel die 4, and the outer peripheral portions of the die 2 and 3 corresponding to the advancement thereof. Press. This pressing is performed from the direction intersecting the optical axis because the pressing members 21 and 22 are arranged so as to intersect perpendicularly to the arrow B direction which is the optical axis direction.

  Each of the pressing members 21 and 22 can be adjusted in height so that the pressing members 21 and 22 can press the upper and lower molds 2 and 3 at an arbitrary height position. The position can be adjusted according to the size. The upper second pressing member 22 is movable in the vertical direction indicated by the arrow C. This is for performing movement in accordance with the lowering of the upper mold 2 during press molding.

  The pressing force in the pressing members 21 and 22 is set so that the lower first pressing member 21 is large and the upper second pressing member 22 is relatively small. That is, as indicated by the lengths of the arrows F1 and F2, the pressing force F1 of the first pressing member is set large and the pressing force F2 of the second pressing member 22 is set small. This is because the first pressing member 21 presses the lower mold 3, and the second pressing member 22 presses the upper mold 2 in this pressed state, so that the body mold 4 falls due to the pressing force of the second pressing member 22. This is to prevent it from occurring.

  Here, the relationship between the support position of the trunk mold 4 by the receiving member 5 and the pressing position of the lower mold 3 by the first pressing member 21 will be described with reference to FIG. When the position where the piston rod 21a of the first pressing member 21 presses the outer peripheral portion of the lower mold 3 is H1, and the positions where the upper and lower ends of the lower mold 3 are in contact with the body mold 4 are H2 and H3, The position where the support protrusion 5a of the receiving member 5 contacts and supports the outer surface of the copper mold 4 is set between H2 and H3. That is, the position where the receiving member 5 supports the body mold 4 is set so as to correspond to the sides of the triangle determined by the three points H1, H2, and H3. When the receiving member 5 supports the body mold 4 at such a position, the piston rod 21 a of the first pressing member 21 presses the lower mold 3, so that the outer peripheral surface of the lower mold 3 is the reference surface 17 of the body mold 4. When the body mold 4 is pressed against the receiving member 5 in contact with the body, the receiving member 5 can support the body mold 4 without tilting. Thereby, the reference surface 17 of the trunk mold 4 can position the lower mold 3 satisfactorily.

  Next, molding of the optical element according to this embodiment will be described. As shown in FIG. 1, the upper mold 2 and the lower mold 3 sandwiching the optical glass material 10 are inserted into the body mold 4 to be in an assembled state, and placed on the lower mold heater plate 7 in this assembled state. At this time, the support protrusion 5a of the receiving member 5 faces the outer surface of the body mold 4 on the reference surface 17 side. Then, the upper mold heater plate 11 and the lower mold heater plate 7 are lightly brought into contact with the respective molds 2 and 3, and the lower mold 3, the upper mold 2, and the body mold 4 are heated by the respective heater plates 7 and 11. . By this heating, the optical glass material 10 sandwiched between the upper mold 2 and the lower mold 3 is heated.

  When the optical glass material 10 is heated to a predetermined moldable temperature, the upper shaft 13 and the lower shaft 8 are driven to bring the upper mold heater plate 11 and the lower mold heater plate 7 relatively close to each other. Thereby, press molding of the optical glass material 10 by the upper mold 2 and the lower mold 3 is started. When the optical glass material 10 is gradually deformed by this pressing and immediately before the end, the pressing is temporarily interrupted, and the upper and lower molds 2 and 3 are positioned by the pressing member 6. Positioning by the pressing member 6 will be described with reference to FIGS. In these drawings, the left half of the body mold 4, that is, the side on which the opening 18 is formed in the body mold 4 is omitted for clarity.

  First, as shown in FIG. 2, the first pressing member 21 extends and the piston rod 21 a passes through the opening 18 of the trunk mold 4 and presses the outer peripheral portion of the lower mold 3 inside the trunk mold 4. By this pressing, the lower mold 3 moves in the body mold 4 and comes into contact with the reference surface 17. In this case, since the outer surface of the barrel die 4 is supported by the support protrusions 5a of the receiving member 5 and the barrel die 4 is stably stopped at a fixed position, the lower die 3 contacts the reference surface 17 of the barrel die 4. Will be in the positioning state.

  Thereafter, the second pressing member 22 is extended while the pressing state by the first pressing member 21 is maintained, and the piston rod 22a passes through the opening 18 of the trunk mold 4 as shown in FIG. Press the outer periphery of the upper mold 2 inside. This pressing is performed from the same direction as the pressing direction of the first pressing member 21, and by this pressing, the upper mold 2 moves in the body mold 4 and comes into contact with the reference surface 17. The contact with the reference surface 17 is performed above the portion where the receiving member 5 supports the body mold 4, but the second pressing member 22 is more than the pressing force F <b> 1 of the first pressing member 21. Since the pressing force F2 is adjusted to be small, the body mold 4 does not tilt in the tilting direction even if the second pressing member 22 is pressed. Therefore, the upper die 2 is positioned with respect to the reference surface 17 that is common with the lower die 3. That is, the upper and lower molds 2 and 3 come into contact with the reference surface 17 of the body mold 4, so that the upper and lower molds 2 and 3 are in a mutually positioned state. When the upper mold 2 is moved, the upper shaft 13, the upper mold heater 12, and the upper mold heater plate 11 are moved in the same direction as the upper mold 2 by the shift free mechanism 14, so that the pressing force on the upper mold 2 is ensured. Can act on.

  After the upper and lower molds 2 and 3 are positioned relative to each other as described above, the pressing force by the pressing members 21 and 22 is reduced so that the upper and lower molds 2 and 3 and the body mold 4 can slide. Then, by further restarting the press, press molding is performed with the upper mold 2 and the lower mold 3 in a state where the optical axes are aligned, and the press is terminated when the target thickness is reached. Then, the upper and lower heater plates 8 and 12 are turned OFF, and after cooling, the upper die plate 12 is raised, and the upper and lower die types 2 and 3 and the barrel die 4 are taken out from the lower die plate 7.

  In such an embodiment, the first pressing member 21 and the second pressing member 22 position the upper and lower molds 2 and 3 in contact with the reference surface of the body mold 4, so that shift shift and tilt shift occur. There is nothing. For this reason, the upper mold | type 2 and the lower mold | type 3 can be positioned with high precision, and an optical element can be shape | molded with high precision. Further, a complicated structure for preventing shift shift and tilt shift is unnecessary, and control is also easy. Further, since it is not necessary for the body mold 4 and the upper and lower molds 2 and 3 to be in contact with each other with a high degree of roundness, wear does not occur between them, and it can be used for a long time.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, the reference surface 17 of the body mold 4 may be any as long as the upper and lower molds 2 and 3 come into contact with each other and can be set according to the outer peripheral surfaces of the upper and lower molds 2 and 3. For this reason, for example, when the upper and lower molds 2 and 3 are cylindrical, they may be a semicircular curved surface or a semicircular curved surface.

  Moreover, the pressing operation by the first pressing member 21 and the second pressing member 22 may be reversed, or the pressing operation may be performed simultaneously. Further, the positioning of the upper and lower molds 2, 3 by these pressing members may be performed before the optical glass material 10 is started to be pressed, or may be performed a plurality of times during pressing by the upper mold 2 and the lower mold 3. Furthermore, the pressing members 21 and 22 may be any one that presses the upper and lower molds 2 and 3 from the direction intersecting the optical axis, and may be a rack and pinion using a motor as a drive source, or other mechanism. .

1 is an overall front view of a molding apparatus according to an embodiment of the present invention. It is a front view which shows the positioning operation | movement of the lower mold | type by a press member. It is a front view which shows the positioning operation | movement of the upper mold | type by a press member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding apparatus 2 Upper mold | type 3 Lower mold | type 4 Body mold | type 5 Receiving member 6 Press member 10 Glass optical material 17 Reference surface 18 Opening part 21 1st press member 22 2nd press member

Claims (5)

In a molding apparatus that forms an optical element by heating and softening an optical glass material,
A pair of molds for pressing the heat-softened optical glass material;
A body mold having a reference surface for positioning between the molds;
A receiving member for supporting the trunk mold;
In order to position the pair of molds in contact with the reference surface of the body mold supported by the receiving member, the pressing of pressing the outer peripheral portions of the pair of molds in the direction intersecting the optical axis from the same direction Members,
An optical element molding apparatus comprising: 2. The optical element molding apparatus according to claim 1, wherein the body mold has a cylindrical shape, and an opening is provided on an outer peripheral surface of the body mold so that the pressing member can advance and retract. The pressing member includes a first pressing member that presses one molding die and a second pressing member that presses the other molding die, and the second pressing member is substantially opposed to the receiving member. The apparatus for molding an optical element according to claim 1, wherein the apparatus is arranged. In the molding method to make the optical element by heating and softening the optical glass material,
A step of inserting a pair of molds and an optical glass material into a barrel mold having a reference surface that serves as a positioning between the molds;
In a state where the position of the barrel mold is regulated, the outer peripheral portions of the pair of molding dies are pressed in the direction intersecting the optical axis from the same direction to bring the pair of molding dies into contact with the reference surface of the trunk mold. A positioning step for positioning;
Forming the optical glass material with a pair of molds;
A method for molding an optical element, comprising: 5. The optical element according to claim 4, wherein in the positioning step, after one mold is brought into contact with a reference surface of the body mold, the other mold is brought into contact with a reference surface of the body mold. Molding method.

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