JP2005255442A - Apparatus for molding optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding apparatus which has a constitution capable of molding a plurality of optical elements in a single press, and which can suppress oxidation of the molding surfaces of molds and prevent sticking of glass on the molding surfaces of the molds at the time of molding operation by enabling ventilation between a space sandwiched by upper and lower molds and the outside of a mold unit. <P>SOLUTION: The molding apparatus is equipped with a body mold 4 arranged on the same circumference in such a manner that the axial centers of a plurality of perforated holes 4a are parallel to each other, molds 2, 3 fitting in each of the plurality of perforated holes 4a and each having a surface for forming the optical surface, a protecting stand 6 for supporting and protecting the body mold and molds, a heating means 13 for heating the body mold and molds to prescribed temperatures, and a pressing means 10, 11 for simultaneously pressing the plurality of molds in the axis center direction of the perforated holes. In the body mold, a plurality of ventilation holes 4b for communicating the perforated holes and open air are formed in the horizontal direction to the axial center, and a connecting hole 4c for connecting at least a portion of the ventilation holes 4b is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical element molding apparatus used when molding an optical element (for example, a glass lens) used in an optical apparatus, and more particularly to a molding apparatus capable of molding a plurality of optical elements with a single press.

  In recent years, for the processing of optical elements such as glass lenses, a press molding method superior in productivity to the polishing method has been introduced and used in optical devices such as digital still cameras and digital video cameras.

Conventionally, in the press molding method, one molded optical element is manufactured by one press. However, in order to further improve productivity, for example, Patent Document 1 and Patent Document 2 include one press. Discloses a technique related to a large number of molding methods capable of molding a large number of optical elements at a time. That is, a molding apparatus is disclosed that is configured so that a plurality of molding dies can be fitted to the body mold, and a plurality of glass materials are heated to a predetermined temperature and then simultaneously pressed.
Japanese Patent Publication No. 4-27175 Japanese Examined Patent Publication No. 6-53580

  However, the conventional mold configuration has the following problems.

  1) The space between the upper and lower molds where the glass material is set is usually filled with air, but because it is completely sealed, it is inert such as nitrogen or hydrogen filled outside the mold unit. It is difficult to replace with gas.

  2) For this reason, the oxidation of the mold forming surface is promoted, the life of the mold is shortened, and glass adheres to the mold forming surface during the molding operation, which causes the productivity to be remarkably deteriorated.

  The present invention enables ventilation between the space between the upper and lower molds in which the glass material is set and the outside of the mold unit, and suppresses the oxidation of the mold molding surface, and the mold molding surface during the molding operation. An object of the present invention is to provide an optical element molding apparatus with high production efficiency that can prevent glass from adhering to the glass.

  The optical element molding apparatus according to the present invention forms an optical surface by fitting a plurality of through-holes on the same circumference with axial axes parallel to each other and the plurality of through-holes. A mold having a surface to be supported, a protection stand for supporting and protecting the barrel mold and the mold, heating means for heating the barrel mold and the mold to a predetermined temperature, and the plurality of the plurality of molds Pressing means for simultaneously pressing the mold in the axial direction of the through hole. The body mold is formed with a plurality of vent holes for communicating the through hole and the outside air in the lateral direction with respect to the axial center, and a coupling hole for connecting at least a part of the vent holes is formed. It is characterized by that.

  According to the optical element molding apparatus having the above configuration, the mold molding surface is prevented from being oxidized by providing a vent hole that allows ventilation between the space between the upper and lower molds where the glass material is set and the outside of the mold unit. In addition, it is possible to prevent the glass from adhering to the molding surface during the molding operation.

  In the optical element molding apparatus according to the present invention, a plurality of the vent holes are provided for each through hole of the body mold, and one coupling hole that is coupled to some of the through holes or adjacent to each other. It can be set as the structure provided with the some coupling hole couple | bonded with a part of vent hole of the said through-hole. Thereby, ventilation efficiency can be improved with fewer ventilation holes.

  Moreover, the said trunk | drum and the said protection stand can be set as the structure mutually positioned by fitting the recessed part provided in any one, and the convex part provided in the other. Thereby, since the generation | occurrence | production of the crack etc. accompanying the relative shift | offset | difference of a trunk | drum and a protection stand can be prevented, the mechanical deterioration of a trunk | drum and a shaping | molding die can be suppressed.

  Hereinafter, an optical element molding apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a main part front view showing the concept of the optical element molding apparatus according to Embodiment 1, in which only the mold unit is shown in cross-sectional shape. FIG. 2 is a perspective view of a mold unit constituting the optical element molding apparatus of FIG. FIG. 3 is a main part front view showing a state after press molding of the apparatus. FIG. 4 shows a cross-sectional view of the mold unit of the apparatus.

  The mold unit 1 includes an upper mold 2, a lower mold 3, a body mold 4, and a protection stand 6. Three through-holes 4a are formed in the body mold 4 (see FIG. 2), and the upper and lower molds 2 and 3 are inserted respectively. The through-hole 4a has a function of maintaining the upper and lower molds 2 and 3 fitted from the openings at both ends in a predetermined positional relationship and keeping the axial misalignment and inclination of the upper and lower molds 2 and 3 within desired accuracy.

  A preformed glass material 7 is placed on the lower mold 3 so as to be sandwiched between the upper mold 2. Also, the body mold 4 has eight vent holes 4b formed in the horizontal direction communicating with the side surfaces of the through holes 4a, with respect to each through hole 4a (see FIGS. 1 and 4). Among the vent holes 4b, the vent hole 4b toward the central portion of the trunk mold 4 is formed so as to intersect with the coupling hole 4c formed in the vertical direction at the central section of the trunk mold 4, and the upper and lower molds 2, 3 The air in the space 8 sandwiched between can be easily replaced with an inert gas that fills the outside of the mold unit 1. Of the outer peripheries that fit into the upper and lower molds 2 and 3 and the outer peripheral part 4, the outer peripheral part on the molding surface side is slightly thinner, and even if the vent hole 4b and the upper and lower molds 2 and 3 are overlapped, they are ventilated. It is possible. Two protrusions 6a and 6b are formed on the protection base 6 and engage with the coupling hole 4c and positioning hole 4d of the body mold 4, respectively, so that the protection base 6 and the body mold 4 are positioned relative to each other. Has been.

  A die set 9 shown in FIG. 1 includes an upper plate 10, a lower plate 11, and a drive cylinder 12. The upper plate 10 slides by a predetermined stroke amount in the directions of arrows X and X ′ by the drive cylinder 12. A cartridge heater 13 and a temperature sensor (not shown) are embedded in the upper plate 10 and the lower plate 11 to heat the upper and lower plates 10 and 11 to a predetermined temperature at which the glass material 7 is softened.

  Next, the process of press-molding a desired optical element using the mold unit 1 and the die set 9 will be described.

  First, in a state in which the lower mold 3 is sandwiched between the trunk mold 4 and the protection stand 6, a glass material 7 in which the lower surface is preformed into a through hole 4 a of the trunk mold 4 and the upper surface is preformed to a plane is supplied. Subsequently, the upper die 2 is fitted and the die unit 1 is assembled. Thereafter, the mold unit 1 is heated using a predetermined heating device such as a tunnel furnace, an oven, or a hot plate (not shown) to heat the glass material 7 to a predetermined temperature at which the glass material 7 can be formed.

  Thereafter, the mold unit 1 is placed on the lower plate 11 of the die set 9 (see FIG. 1), the upper plate 10 is lowered, and the glass material 7 is pressed and deformed through the upper mold 2. Then, as shown in FIG. 3, the upper plate 10 is lowered to a position where the flange of the upper die 2 contacts the barrel die 4, and the press molding is completed. Thereafter, the mold unit 1 is removed from the die set 9, and the molded glass is cooled to a predetermined temperature, whereby the molded optical element 14 is completed.

  The positioning of the body mold 4 and the protection table 6 is not limited to the configuration in which the protection table 6 is provided with a convex portion, and for example, a configuration as shown in FIG. That is, a positioning hole 6c having a small diameter is formed at the same position as the positioning hole 4d of the body mold 4 in the protection stand 6, and the stepped pin 15 is attached to the two holes 4d and 6c, whereby the body mold 4 And positioning of the protection stand 6 can be performed.

  Moreover, the following advantages are acquired by using the protection stand 6. FIG. That is, when moving through the heating, pressing, and cooling steps, the back surface of the protection table 6 is quickly deteriorated due to frictional wear during movement compared to other members. Since it does not wear at all, the service life is extended. If the protective base 6 cannot function as a mold because of non-uniform temperature, only the protective base 6 is replaced, and the upper mold 2, the lower mold 3, or the trunk mold 4 can be used as it is. it can.

(Embodiment 2)
FIG. 6 is a cross-sectional view showing a trunk mold in the second embodiment. 16 through holes 4b are formed in each through hole 4a, and some of the through holes 4b intersect with four coupling holes 4c formed in the vertical direction. This structure increases ventilation efficiency.

The poor glass adhesion at the time of press molding depends on the shape of the optical element and the composition of the glass. For example, a concave meniscus lens tends to cause poor glass adhesion compared to a convex lens. In addition, glass having a small composition ratio of silica (SiO ₂ ) or boron (BaO) in the glass composition tends to cause poor glass adhesion. For these difficult-to-mold shapes and unstable glass materials, the moldability is stabilized by increasing the area of the air holes. Therefore, this embodiment is particularly effective when used for such a shape and glass material with unstable formability.

  According to the optical element molding apparatus of the present invention, it is possible to suppress the oxidation of the mold molding surface to mold the glass material, and to prevent the glass from adhering to the mold molding surface during the molding operation, and to increase the glass lens and the like. It is suitable for molding with production efficiency.

The principal part front view which shows notionally the optical element shaping | molding apparatus in Embodiment 1 Perspective view of a mold unit constituting the optical element molding apparatus The principal part front view which shows the state after the press completion in the optical element shaping | molding apparatus Cross-sectional view of the mold unit of the optical element molding apparatus Sectional drawing which shows the modification of the optical element shaping | molding apparatus 1 is a cross-sectional view showing a body mold that constitutes an optical element molding apparatus according to Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold unit 2 Upper mold 3 Lower mold 4 Body mold 4a Through hole 4b Vent hole 4c Joint hole 4d Positioning hole 6 Protection stand 7 Glass material 8 Space 9 Die set 10, 11 Plate 12 Drive cylinder 13 Cartridge heater

Claims (3)

A barrel mold in which a plurality of through holes are arranged on the same circumference with their axes parallel to each other; a mold having a surface that fits into each of the plurality of through holes and forms an optical surface; A protection stand for supporting and protecting the body mold and the mold, heating means for heating the body mold and the mold to a predetermined temperature, and the plurality of molds as the axis of the through hole In an optical element molding apparatus provided with pressing means for simultaneously pressing in the direction,
The body mold is formed with a plurality of ventilation holes for communicating the through holes and the outside air in the lateral direction with respect to the axial center, and a coupling hole for connecting at least a part of these ventilation holes is formed. An optical element molding apparatus.   A plurality of the vent holes are provided for each through hole of the trunk mold, and one of the through holes is coupled to one of the through holes, or one of the adjacent through holes. The optical element molding apparatus according to claim 1, further comprising a plurality of coupling holes coupled to the portion.   The optical element molding apparatus according to claim 1, wherein the body mold and the protection stand are positioned relative to each other by fitting a concave portion provided on one side and a convex portion provided on the other side.

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