JP2005231946A - Apparatus and method for manufacturing glass preform, glass preform and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable manufacturing of a glass preform of an optical element without inducing galling of molds. <P>SOLUTION: A glass preform manufacturing apparatus is the one for manufacturing the glass preform 10 which has a shape close to the final shape of the glass optical element and is processed into the optical element through finishing. The apparatus is equipped with a lower mold 1 for molding the lower surface of the glass preform, an upper mold 2 for molding the upper surface of the glass preform, a lower concave mold 3 which is fixed onto the lower mold and molds the lower lateral surface of the glass preform and an upper concave mold 4 which is placed so that it can be freely attached to and detached from the upper mold and the lower concave mold and molds the upper lateral surface of the glass preform. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for forming a glass preform used as a molding material or a polishing material by molding molten optical glass with a molding die.

Conventionally, when manufacturing a glass optical element, first a glass preform having a shape close to the completed shape of the optical element is manufactured, and the glass preform is finished by polishing to manufacture a final optical element. Has been taken. As a technique for producing a glass preform used as a polishing material, as disclosed in JP-A-10-120424, JP-A-60-251135, etc., molten optical glass is used in a mold. Techniques for molding and manufacturing are known. In these, the structure of the upper mold that presses the molten glass lump and forms a preform having a peripheral edge shape consists of an upper mold and a sleeve around the upper mold, and after forming a cavity by contacting the sleeve and the lower body mold The upper and lower molds were brought close to each other and molded to the peripheral edge shape.
Japanese Patent Laid-Open No. 10-120424 JP 60-251135 A

  However, in the conventional method, there is a problem that galling occurs in the movable sliding portion of the upper mold and the sleeve. Conventionally, this has been dealt with by applying a lubricant to the movable sliding portion.

  In addition, the following two causes can be considered as a cause of galling easily in the movable sliding portion of the upper mold and the sleeve.

  The first point is that there are many sliding parts. That is, the sleeve slides with the upper mold all around the inner circumference, and a holder is often provided outside the sleeve, and the sleeve also slides with the holder. That is, the entire circumference of the sleeve slides on both the inner and outer surfaces. Therefore, galling is generated only by a slight eccentricity or a slight inclination of the sleeve.

  The second point is the inclination of the sleeve by glass. That is, in the conventional method, after forming the cavity by bringing the sleeve and the lower body mold into contact, when the upper and lower molds are brought close to each other to form the peripheral edge shape, the molten glass flows out from the contact portion between the sleeve and the lower body mold. The spilled glass may lift the sleeve in a biased state. When the sleeve is tilted in this manner, the frequency of occurrence of galling increases. The outflow of molten glass from the contact portion between the sleeve and the lower body mold occurs when the sleeve and the lower body mold are brought into contact with each other or when the upper and lower molds are brought close to each other.

  By the way, when the glass preform is polished and finished in a post-process as in the prior art, the use of this lubricant is not particularly problematic. That is, the surface of the molded glass preform is removed by grinding and polishing to become an optical element, so that the lubricant adhering to the glass preform surface is finally removed.

  However, when a glass preform is further press-molded to produce an optical element, adhesion of a lubricant to the glass preform surface is not preferable because it causes poor appearance and poor optical performance of the molded optical element.

  Further, in recent years, some molded optical elements have a large number of optical surfaces and the overall shape is close to a rectangular parallelepiped. In this way, when a glass preform having a substantially rectangular parallelepiped shape is press-molded by a conventional method, the sleeve shape becomes rectangular. When such a rectangular sleeve is used to form a glass preform from molten glass by a conventional method, galling is very likely to occur. This is presumably because the rectangular sleeve has a poor balance and the shape accuracy is poor compared to the circular sleeve of a general lens.

  Accordingly, the present invention has been made in view of the above-described problems, and is to enable production of a glass preform of an optical element without galling.

  In order to solve the above-described problems and achieve the object, a glass preform manufacturing apparatus according to the present invention has a shape close to a completed shape of a glass optical element, and finishes the optical element. A glass preform manufacturing apparatus for manufacturing a glass preform to be processed, a lower mold for forming the lower surface of the glass preform, an upper mold for forming the upper surface of the glass preform, and the lower A lower body mold that is fixed to a mold and forms a lower side part of the side surface of the glass preform, and is detachably disposed on the upper mold and the lower body mold, and forms an upper side part of the side surface of the glass preform. And an upper torso mold.

  Further, the glass preform manufacturing apparatus according to the present invention is further characterized by further comprising a vacuum adsorption means for integrating the upper body mold with the upper or lower body mold.

  Further, the glass preform manufacturing apparatus according to the present invention is characterized by further comprising gas jetting means for floating the upper body mold from the upper mold or the lower body mold.

  In the glass preform manufacturing apparatus according to the present invention, the upper body mold and the lower body mold have an inclined surface acting as a draft on the inner periphery thereof.

  Moreover, the manufacturing method of the glass preform concerning this invention is a method of manufacturing a glass preform using said manufacturing apparatus of a glass preform, Comprising: The said upper trunk mold was integrated with the said lower trunk mold In a state, the first step of receiving molten glass on the lower mold to obtain a molten glass lump, the upper mold and the lower mold are brought close to each other, and the upper trunk mold is changed to the upper mold and the lower trunk mold. The glass preform is pressed by a space surrounded by the upper mold, the lower mold, the upper trunk mold, and the lower trunk mold by pressing the molten glass lump with the upper mold and the lower mold. In the second step of molding the glass preform, the third step of cooling the glass preform, the upper body mold integrated with the upper mold, and detached from the lower body mold, the upper mold And open the lower mold and the glass preform A fourth step of issuing Ri, characterized by including the.

  In the glass preform manufacturing method according to the present invention, in the first step, the upper body mold is integrated with the lower body mold by vacuum adsorption.

  In the glass preform manufacturing method according to the present invention, in the fourth step, the upper body mold is integrated with the upper mold by vacuum adsorption.

  In the glass preform manufacturing method according to the present invention, in the fourth step, the upper body mold is separated from the lower body mold by ejecting gas from the lower body mold. .

  Further, the glass preform according to the present invention is a glass preform in which an upper surface and a lower surface are press-molded by upper and lower molding dies, on a side surface between the upper surface and the lower surface, in an intermediate portion in the vertical direction of the side surface. It is characterized by comprising slopes whose inclinations are opposite to each other.

  An optical element according to the present invention is manufactured by finishing the above glass preform.

  According to the present invention, a glass preform of an optical element can be produced without galling.

  Hereinafter, a preferred embodiment of the present invention will be described.

  First, an outline of the present embodiment will be described.

  A first feature of the present embodiment is that, in an apparatus for manufacturing an optical glass preform having a controlled peripheral edge shape, a forming die receives a molten glass lump and forms a lower surface of the preform. The body mold for forming the peripheral edge shape of the side surface of the preform and the upper mold yp for molding the upper surface of the preform. The body mold can be divided into upper and lower body molds and divided into upper and lower bodies. The trunk mold is a structure that can be easily integrated with the lower trunk mold and the upper mold and detached therefrom.

The second feature of the present embodiment is that the upper body mold is the above glass preform manufacturing apparatus,
(1) Placed on the lower body mold and combined with and integrated with the lower body mold and separated from the upper mold (2) Placed on the lower body mold and combined with the upper mold, that is, lower It is integrated with both the body mold and the upper mold to form a molding cavity. (3) It is combined with the upper mold and integrated, and can be changed into three states separated from the lower body mold. .

  The third feature of the present embodiment is that in the glass preform manufacturing method using the above manufacturing apparatus, the upper body mold is combined with the lower body mold and integrated, and the lower mold is surrounded by the upper and lower body molds. The molten glass mass is received on the upper mold, and then the upper and lower molds are brought close to each other, and the upper mold placed on the lower mold is integrated with the upper mold, and the molten glass mass is formed in the formed cavity. To obtain an optical glass preform having a controlled peripheral edge shape, and after the glass preform is cooled, the upper body mold is integrated with the upper mold and separated from the lower mold The mold opening is performed by taking out the molded glass preform.

  The fourth feature of the present embodiment is that, in the glass preform manufacturing apparatus, the inner periphery of the upper and lower body molds forms a peripheral edge shape that acts as a draft.

  The fifth feature of the present embodiment is that, in the glass preform manufacturing apparatus, the upper body mold is combined with the upper mold by reduced-pressure adsorption.

  A sixth feature of the present embodiment is that, in the glass preform manufacturing apparatus, the upper body mold is combined with the lower body mold, and the jet gas is provided between the upper body mold and the lower body mold. It is in a state where it is lightly levitated by the gas cushion layer due to or a state where it is adsorbed to each other by reduced pressure adsorption.

  In addition, the seventh feature of the present embodiment is that the glass preform obtained by the above method is used as a molding material, and an optical element is obtained by precision molding.

  The eighth feature of the present embodiment is that an optical element is obtained by grinding and polishing the glass preform obtained by the above method as a polishing material.

  The effects of the first, second, and third features are as follows.

  First, the upper body mold is combined and integrated with the lower body mold, and a molten glass lump is received on the lower mold surrounded by the upper and lower body molds. Thereby, the molten glass lump is held by the upper and lower body molds and does not flow out of the cavity. Since the upper body mold is combined and integrated with the lower body mold, molten glass does not flow out from this mating surface.

  Next, the upper and lower molds are brought close to each other, the upper trunk mold placed on the lower trunk mold is combined with the upper mold and integrated, and a molten glass lump is molded in the formed molding cavity to control the peripheral edge shape. An optical glass preform having is obtained. At this time, the upper mold moves closer to the lower mold while sliding with the upper trunk mold, but the sliding portion of the upper trunk mold is only the inner surface of the upper trunk mold, and there are few sliding sections, Since there is no outflow of glass from the mating surfaces of the upper and lower body molds, there is no inclination of the upper body mold and no galling occurs.

  Further, after the glass preform is cooled, the upper body mold is integrated with the upper mold and the mold is opened in a state where it is detached from the lower body mold, and the molded glass preform is taken out. At this time, since the upper body mold is opened in a state of being integrated with the upper mold, it is very easy to take out the molded glass preform.

  Moreover, according to said 4th characteristic, taking out of a shaping | molding glass preform becomes very easy by forming the peripheral edge shape which acts as a draft on the inner periphery of an upper and lower body type | mold.

  Moreover, according to said 5th characteristic, an upper mold | type and an upper trunk | drum can be reliably integrated by making a state combined with the upper mold | type by decompression adsorption | suction, and also an adsorption | suction By converting the pressure into positive pressure, the upper mold and the upper trunk mold can be reliably separated.

  Further, according to the sixth feature, the upper trunk mold and the lower trunk mold are combined, and the gap between the upper trunk mold and the lower trunk mold is lightly levitated by the gas cushion layer of the jet gas, Positioning of the upper body mold and the lower body mold can be facilitated, and the upper body mold and the upper mold can be reliably integrated. In addition, by making the upper body mold and the lower body mold adsorbed to each other by vacuum adsorption, the upper body mold and the lower body mold can be reliably integrated, and the molten glass flows out of this mating surface. Can be prevented.

  Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating a configuration in the vicinity of a molding die of a molding apparatus according to an embodiment of the present invention.

  In FIG. 1, 1 is a lower mold, 2 is an upper mold, 3 is a lower trunk mold, 4 is an upper trunk mold, 5 is a lower mold holder, 6 is an upper mold holder, 7 is a heater, 8 is a decompression chamber, and 9 is suction. It is a tube.

  The lower mold 1 is held by a lower mold holder 5 and heated to a predetermined temperature by a heater 7. The lower body mold 3 is placed on the outer periphery of the lower mold 1 and integrated with the lower mold 1 by a lower mold holder 5. The upper mold 2 is held by the upper mold holder 6 and heated to a predetermined temperature by the heater 7. The upper trunk mold 4 is located on the outer periphery of the upper mold 2, but the upper trunk mold 4 and the upper mold 2 are not fixed. An annular decompression chamber 8 is installed inside the upper and lower mold holders 5 and 6, and a plurality of suction pipes 9 are provided from the decompression chamber 8 so as to penetrate to the outside. The upper trunk mold 4 is installed so as to be fitted to the upper mold 2 or the lower trunk mold 3 at a position where the suction pipe 9 is opened. The decompression chamber 8 is connected to a decompression device (not shown) such as a vacuum pump or a gas supply device (not shown). By decompressing the decompression chamber, the upper body mold 4 can be adsorbed under reduced pressure. By supplying gas to the decompression chamber, decompression adsorption can be released, and the upper body mold 4 can be lifted lightly.

  In addition, the taper surface is formed in the inner surface which comprises the cavity 20 of the lower trunk mold 3 and the upper trunk mold 4 so that it may act as a draft of a molded product.

  FIG. 2 is a process explanatory diagram for explaining a method of manufacturing an optical glass preform having a controlled peripheral edge shape, that is, a molded glass lump.

  In FIG. 2, 10 is a molten glass block, and 11 is an optical glass preform having a shaped glass block or controlled peripheral edge shape. Although not shown in FIG. 2, the lower mold holder 5 is connected to an NC driving device whose movement speed can be controlled to a predetermined value, and can move at a predetermined speed in the vertical and horizontal directions. It is.

  In the initial stage of the process, the upper body mold 4 is placed on the lower body mold 3 in a fitted state and integrated. At this time, the upper body mold 4 is vacuum-sucked and integrated with the lower body mold 3.

  Subsequently, the molten glass lump 10 is received on the lower mold 1. That is, the lower mold 1 is positioned directly below the molten glass outlet (not shown), receives the molten glass flow flowing out from the molten glass outlet on the lower mold 1, waits until the desired weight is reached, and the desired weight. After receiving the molten glass, the lower mold 1 is lowered by a predetermined distance to form a constricted portion in the molten glass flow and waits for a while, the molten glass flow is separated and cut by the surface tension of the molten glass, and the molten glass lump 10 is lowered to the lower mold. Get on top of one.

  The lower mold 1 that has received the molten glass lump 10 moves laterally from a position below the molten glass outlet (not shown) to a position below the upper mold 2. Thereafter, the lower mold 1 is raised at a predetermined controlled speed, and press molding of the molten glass lump 10 is started.

  First, the outer peripheral surface of the upper mold 2 is inserted into the inner peripheral surface of the upper body mold 4 in a fitted state. At this time, since the sliding surfaces of the upper body mold 4 and the upper mold 2 are only this surface, no galling occurs.

  Then, with the molding cavity formed by the lower mold 1, the upper mold 2, the lower trunk mold 3, and the upper trunk mold 4, when the lower mold 1 further rises, press molding of the molten glass lump 10 is performed. Beginning, the molten glass mass spreads to the periphery and eventually fills the molding glass with a controlled peripheral edge shape. At this time, since the lower body mold 3 and the upper body mold 4 are integrated by reduced-pressure adsorption, the molten glass does not flow out from this mating surface.

  Thus, after the molten glass is filled into the cavity and cooled and solidified, the molded glass mass 11, ie the optical glass preform having a controlled peripheral edge shape, is removed from the mold.

  At this time, the upper body mold 4 is vacuum-adsorbed and integrated with the upper mold 2, and conversely, gas is supplied to the lower body mold 3 through the suction pipe 9, so that it is lightly floated. . When the lower mold 1 is lowered in this state, the molded glass lump 11 is placed on the lower mold 1, and the mold is opened from the upper mold 2 integrated with the upper body mold 4. At this time, the upper body mold 4 slides between the side surfaces of the molded glass lump 11, but since a tapered draft is formed on this surface, no galling occurs.

  Then, the molded glass lump 11 is taken out using a carry-out device (not shown). At this time, since a tapered draft is formed on the side surface of the lower body mold 3, it is very easy to take out.

  After the molded glass block is taken out in this way, the lower mold 1 rises again and is integrated with the upper mold 2. At this time, the upper trunk mold 4 receives from the upper mold 2 side to the lower trunk mold 3 side. Passed. At this time, it is preferable that the upper body mold 4 is transferred between the lower body mold 3 and the upper body mold 4 in a lightly floated state by gas ejection from the suction pipe 9 without galling.

  After the delivery of the upper body mold 4 is completed, the upper body mold 4 and the lower body mold 3 are integrated by decompression suction, and a light floating state is obtained between the upper body mold 4 and the upper mold 2 by gas supply from the suction pipe 9. After that, the lower mold 1 is lowered, the upper body mold 4 is detached from the upper mold 2 and integrated with the lower body mold 3, thereby producing an optical glass preform having a controlled peripheral edge shape. Complete.

  Hereinafter, specific examples of the present embodiment will be described.

(Example 1)
In Example 1, an example of obtaining an optical element by pressing a molten glass lump using an upper and lower molds made of a porous material to obtain a shaped glass lump, and removing a molding surface of the shaped glass lump by grinding and polishing. explain.

  The apparatus configuration in this embodiment is the same as that shown in FIG. In this embodiment, the lower mold 1 and the upper mold 2 are made of a porous material, and a gas supply chamber (not shown) is provided on the back surface of these molds, and the high pressure supplied to the gas supply chamber. Is designed to be ejected from the mold surface through the pores of the porous material mold.

  In this example, a case where an optical glass equivalent to SK12 is melted, a molten glass lump is obtained therefrom, and press molding is performed to obtain a glass preform will be described.

  As porous materials for the upper and lower molds, two types of carbon and zirconia / mica composite materials were examined. In the case of carbon, nitrogen gas was used as the ejection gas. In the case of a zirconia / mica composite material, air was used as the jet gas.

  In this example, the same material was used for the four members of the lower mold 1, the upper mold 2, the lower trunk mold 3, and the upper trunk mold 4.

  The shape of the molded glass lump in this example is a biconvex shape having a diameter of 20 mm, and its weight is 5 g.

  The lower mold 1 is heated and held at 400 ° C. by the heater 7 in the lower mold holder 5, and the upper mold 2 is heated and held at 350 ° C. by the heater 7 in the upper mold holder 6.

  The molten glass flows out from a molten glass outlet (not shown) at 1000 ° C., and flows out onto the lower mold 1 for 7 seconds to obtain a molten glass lump having a weight of 5 g. Move it down. And after hold | maintaining there for 3 second, the lower mold | type 1 was raised and press-molded, and it hold | maintained in that state for 5 second, after cooling and solidifying glass, the mold was opened and the shaping | molding glass lump (glass preform) 11 was taken out.

  The movement of the upper body mold 4 in this example is the same as that described in the above embodiment. In this example, no malfunction such as galling of the upper body mold 4 occurred, and continuous molding of continuous 5000 shots was possible.

  Further, in this example, the gas flow rate ejected from the molding surface of the mold is controlled to a desired value, so the surface of the glass molding surface lightly transfers the pores of the mold, and the surface is uneven. The surface shape was very close to the surface shape of the mold.

  Thus, since the shape accuracy of the molded glass block (glass preform) obtained in this example is extremely high, the amount of removal required for grinding and polishing the molding surface of this molded glass block to obtain an optical element is a little. 50 μm was sufficient.

(Example 2)
In Example 2, an example will be described in which a molten glass lump is press-molded by using an upper and lower mold made of an alloy material to obtain a molded glass lump, and the molded glass lump is precisely molded to obtain a molded optical element.

  The apparatus configuration in this embodiment is the same as that shown in FIG.

  In the present embodiment, a case will be described in which optical glass equivalent to SK12 is melted to obtain a molten glass lump and press-molded to obtain a shaped glass lump (glass preform).

  In this example, as a material of four members of the lower mold 1, the upper mold 2, the lower trunk mold 3, and the upper trunk mold 4, a material made of an alloy of gold and nickel was used.

  The shape of the molded glass lump in this example is a concave meniscus shape with a diameter of 26 mm, and its weight is 7 g.

  The lower mold 1 is heated and held at 450 ° C. by the heater 7 in the lower mold holder 5, and the upper mold 2 is heated and held at 400 ° C. by the heater 7 in the upper mold holder 6.

  The molten glass flows out from a molten glass outlet (not shown) at 1000 ° C., and flows out onto the lower mold 1 for 9 seconds to obtain a molten glass lump having a weight of 7 g. Move it down. And after hold | maintaining there for 5 second, the lower mold | type 1 was raised and press-molded, and it hold | maintained in that state for 8 seconds, after cooling and solidifying glass, the mold was opened and the shaping | molding glass lump 11 was taken out.

  The movement of the upper body mold 4 in this example is the same as that described in the above embodiment. In this example, no malfunction such as galling of the upper body mold 4 occurred, and continuous molding of continuous 5000 shots or more was possible.

  Since the gold-nickel alloy used as a mold material in this example has low reactivity with molten optical glass and poor wettability, the appearance of the molded glass lump 11 is very good and suitable as a material for molding an optical element. Yes.

  When precision molding is performed using a molded glass lump 11 molded in a shape approximate to the desired molded optical element shape as a molding material, there are the following two advantages because the amount of deformation during molding is small.

  One is that it is sufficient to set the temperature in the vicinity of the surface of the molding material to be deformable, so that the time required for heating the glass is shortened. The other is that damage to the mold is reduced.

  In this example, a precision molding die in which a carbon mold release film was provided on the molding surface of a molding die body made of a super hard material as a precision molding die was heated to 610 ° C. to perform precision molding. .

  The time required for heating the glass required 150 seconds in the conventional precision molding, but 40 seconds was sufficient in this example.

  Further, in the conventional precision molding, the durability of the carbon release film on the molding surface was 1000 shots, but in this example, the durability was 5000 shots or more.

(Example 3)
In the third embodiment, a case where an optical element having a non-lens shape, that is, a prismatic reflective optical element having a plurality of reflecting surfaces is obtained by the same method as in the second embodiment will be described.

  3 and 4 show an apparatus configuration in the present embodiment. 3 is a longitudinal sectional view in the longitudinal direction, and FIG. 4 is a transverse sectional view. The basic configuration is the same as that of the first embodiment shown in FIG. In the present embodiment, the mating surface of the lower body mold 3 and the upper body mold 4 has a refracting surface shape unlike the plane of the second embodiment. This comes from the shape factor of the prismatic reflective optical element.

  FIG. 5 is a process explanatory view showing the operation of the apparatus at the time of molding a molded glass lump (glass preform) in this example. The apparatus operation is the same as that of the second embodiment shown in FIG.

  In this example, a case will be described in which a phosphoric acid-based extremely low softening optical glass is melted to obtain a molten glass lump, which is then press-molded to obtain a shaped glass lump.

  In this example, as a material of four members of the lower mold 1, the upper mold 2, the lower trunk mold 3, and the upper trunk mold 4, a material made of an alloy of gold and nickel was used.

  The shaped glass lump in this example has a shape having six optical surfaces as shown in FIGS. 3 and 4, the length of the shaped glass lump is 20 mm, and its weight is 14 g.

  The lower mold 1 is heated and held at 300 ° C. by a heater (not shown) in a lower mold holder (not shown), and the upper mold 2 is 250 by a heater (not shown) in the upper mold holder (not shown). Heated to 0 ° C.

  As the molten glass outlet (not shown) used in this example, a rectangular shape whose opening shape approximated the shape of the mold cavity was used.

  The molten glass flows out from the molten glass outlet (not shown) at 750 ° C., and flows out onto the lower mold 1 for 12 seconds to obtain a molten glass lump having a weight of 14 g. Move it down. And after holding for 8 seconds there, the lower mold | type 1 was raised and press-molded, and after hold | maintaining for 4 seconds in that state, the glass was cooled and solidified, the mold was opened, and the shaping | molding glass lump 11 was taken out.

  The movement of the upper body mold 4 in this example is the same as that described in the above embodiment. In this example, no malfunction such as galling of the upper body mold 4 occurred, and continuous molding of continuous 5000 shots or more was possible.

  Since the gold-nickel alloy used as a mold material in this example has low reactivity with molten optical glass and poor wettability, the appearance of the molded glass lump 11 is very good and suitable as a material for molding an optical element. Yes.

  In the case of obtaining a molded optical element having a complicated shape such as a prismatic reflective optical element having a plurality of reflecting surfaces as in the present embodiment, the molding material needs to approximate the shape of the molded element. According to the present embodiment, a molding material having such a complicated shape can be obtained easily and inexpensively.

  In this embodiment, a precision mold having a carbon mold release film provided on the molding surface of a mold body using a cemented carbide as a base material is used as the precision mold, and this mold is heated to 430 ° C. to perform precision molding Was done. In this manner, a prismatic reflective optical element having a plurality of reflective surfaces, which is a complex shaped molded optical element, could be obtained.

  As described above, according to the above-described embodiment, it is possible to reliably manufacture an optical glass preform having a controlled peripheral edge shape, increase the apparatus operating rate, and reduce the manufacturing cost.

  Moreover, the manufacturing cost at the time of manufacture of a shaping | molding optical element can be reduced by using the shaping | molding raw material of an approximate shape.

  In addition, the amount of removal processing at the time of manufacturing the optical element can be greatly reduced, and the manufacturing cost can be reduced.

It is a figure explaining the type | mold structure in the 1st and 2nd Example. It is a figure explaining the manufacturing method in the 1st and 2nd Example. It is a figure explaining the type | mold structure in a 3rd Example. It is a figure explaining the type | mold structure in a 3rd Example. It is a figure explaining the manufacturing method in a 3rd Example.

Explanation of symbols

1 Lower mold 2 Upper mold 3 Lower trunk mold 4 Upper trunk mold 10 Molten glass lump 11 Molded glass lump

Claims (10)

A glass preform manufacturing apparatus for manufacturing a glass preform that has a shape close to a completed shape of a glass optical element and is processed into the optical element by finishing.
A lower mold for molding the lower surface of the glass preform;
An upper mold for molding the upper surface of the glass preform;
A lower body mold that is fixed to the lower mold and molds the lower side of the side surface of the glass preform;
An upper trunk mold that is detachably disposed with the upper mold and the lower trunk mold, and that molds the upper side portion of the side surface of the glass preform;
An apparatus for producing a glass preform, comprising:   The apparatus for producing a glass preform according to claim 1, further comprising a vacuum adsorption means for integrating the upper body mold with the upper or lower body mold.   The apparatus for producing a glass preform according to claim 1, further comprising gas jetting means for floating the upper body mold from the upper or lower body mold.   The apparatus for producing a glass preform according to claim 1, wherein the upper body mold and the lower body mold have inclined surfaces that act as drafts on the inner periphery thereof. A method for producing a glass preform using the glass preform production apparatus according to claim 1,
In a state where the upper body mold is integrated with the lower body mold, a first step of receiving molten glass on the lower mold to obtain a molten glass lump,
The upper mold and the lower mold are brought close to each other, the upper trunk mold is integrated with the upper mold and the lower mold, and the molten glass lump is pressed by the upper mold and the lower mold. A second step of forming the glass preform by a space surrounded by the lower mold, the upper trunk mold, and the lower trunk mold;
A third step of cooling the glass preform;
A fourth step of integrating the upper body mold with the upper mold and opening the upper mold and the lower mold in a state of being detached from the lower mold, and taking out the glass preform;
A method for producing a glass preform, comprising:   6. The method for producing a glass preform according to claim 5, wherein in the first step, the upper body mold is integrated with the lower body mold by vacuum adsorption.   6. The method for producing a glass preform according to claim 5, wherein in the fourth step, the upper body mold is integrated with the upper mold by vacuum adsorption.   In the fourth step, the method for producing a glass preform is characterized in that the upper body mold is separated from the lower body mold by ejecting gas from the lower body mold. A glass preform whose upper and lower surfaces are press-molded by upper and lower molds,
A glass preform comprising, on a side surface between the upper surface and the lower surface, inclined surfaces whose inclinations are opposite to each other at an intermediate portion in the vertical direction of the side surface.   An optical element manufactured by finishing the glass preform according to claim 9.

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