JP2010105871A - Method and apparatus for manufacturing optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing the optical device by which the wear of a mold is suppressed while cutting waste in consistent manufacturing steps started from molten glass. <P>SOLUTION: The method of manufacturing the optical device GC has a step of receiving the molten glass on a receiving surface 33 of a supporting member 30 and holding to form a molten glass gob FG and transferring the molten glass gob FG on the receiving surface 33 into the mold 60 for press molding at the point of time when the logarithm logη of the viscosity (dPa s) of the molten glass gob FG becomes ≥1 and ≤6.65 and press-molding the molten glass gob FG in the mold 60. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for manufacturing an optical element.

  Conventionally, an optical element has been manufactured by polishing glass cut out from plate glass, polishing it into a shape approximate to the optical element, and heat-molding the polished product. However, when producing an aspheric lens, this method increases the polishing cost of the glass material. Therefore, a method of forming an aspheric lens by pressure molding with a mold is used.

In recent years, a method for consistently producing an optical element from molten glass while using a mold press technique has been proposed. For example, Patent Documents 1 and 2 disclose a technique in which molten glass is received and held by a receiving surface of a support member, and the formed preform is transferred into a mold and press-molded. Patent Document 3 discloses a technique in which molten glass is directly received and held by a receiving surface of a support member, and the formed molten glass lump is transferred into a mold and press-molded.
JP 2004-203740 A JP 2004-168660 A JP-A-6-340430

  However, in the methods disclosed in Patent Documents 1 and 2, since the preform needs to be reheated during transfer to the mold, the process is wasted and the lead time is very long. On the other hand, in the method disclosed in Patent Document 3, the mold is easily consumed at a high temperature of the molten glass lump.

  The present invention has been made in view of the above circumstances, and provides an optical element manufacturing method and a manufacturing apparatus capable of suppressing consumption of a mold while eliminating waste in a consistent manufacturing process from molten glass. Objective.

  The inventors have found that by performing the transfer to the mold when the viscosity of the molten glass lump is in a predetermined range, it is possible to suppress the consumption of the mold without performing reheating during the transfer, The present invention has been completed. Specifically, the present invention provides the following.

(1) Receive and hold the molten glass on the receiving surface of the support member to form a molten glass lump,
When the logarithm log η of the viscosity (dPa · s) is 1 or more and 6.65 or less, the molten glass lump on the receiving surface is transferred into a press molding die,
The manufacturing method of the optical element which has the process of press-molding the molten glass lump in the said metal mold | die.

  (2) The method according to (1), wherein the molten glass lump is transferred by dropping the molten glass lump from the receiving surface to the mold.

(3) The support member is made of a porous member whose receiving surface can be divided into two or more,
The manufacturing method according to (1) or (2), wherein a temperature-controlled gas is ejected from the receiving surface to float the molten glass lump.

  (4) The production method according to (3), wherein the gas is ejected so that the temperature of the molten glass block is decreased at a rate of −700 ° C./min or more and −100 ° C./min or less.

  (5) A method for manufacturing an optical device using the optical element manufactured by the manufacturing method according to any one of (1) to (4).

(6) A support member having a receiving surface for receiving molten glass, a press molding apparatus having a press molding die, and a transfer for transferring a molten glass mass held and formed by the receiving surface into the die. And an optical element manufacturing apparatus comprising:
Detecting means for detecting the temperature of the molten glass lump and calculating the viscosity;
And a transfer control means for controlling the transfer means based on the viscosity calculated by the detection means.

  (7) The manufacturing apparatus according to (6), wherein the transfer unit drops the molten glass lump from the receiving surface onto the mold.

(8) The receiving surface is made of a porous member that can be divided into two or more,
The manufacturing apparatus according to (6) or (7), further including gas supply means for ejecting a temperature-controlled gas from the receiving surface.

  (9) The manufacturing apparatus according to (8), further comprising supply control means for controlling the gas supply means based on the temperature detected by the detection means.

  (10) An optical device manufacturing apparatus that manufactures an optical device using the optical element manufactured by the manufacturing device according to any one of (6) to (9).

  According to the present invention, the transfer to the mold is performed when the viscosity of the molten glass lump reaches a predetermined range, so that the need for reheating is low and the transfer time can be shortened, and the mold is formed at an optimum temperature. Since it is transferred, the consumption of the mold can be suppressed and the molding time can be shortened.

  Hereinafter, although one embodiment of the present invention is described with reference to drawings, the present invention is not limited to this.

  FIG. 1 is a diagram showing a procedure of an optical element manufacturing method using an optical element manufacturing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the optical element manufacturing apparatus includes a molten glass supply device 20, a support member 30, a transfer unit 40 as a transfer unit, a control device 50, and a mold 60. Hereinafter, each component will be described in detail.

  The molten glass supply device 20 has a supply pipe 21, and a base portion of the supply pipe 21 is communicated with the inside of a melting tank (not shown) that stores the molten glass. Thereby, the molten glass in the melting tank flows out through the supply pipe 21.

  The support member 30 has a receiving surface 33, and receives the molten glass from the supply tube 21 on the receiving surface 33 disposed below the supply tube 21. Thus, since the receiving surface 33 contacts extremely high-temperature molten glass, it is preferable that the receiving surface 33 be formed of a material having excellent heat resistance. When the molten glass is held on the receiving surface 33, the molten glass is cooled and eventually a molten glass lump FG is formed.

  During this time, after receiving the molten glass on the receiving surface 33, the support member 30 is moved from the lower position of the supply pipe 21 (hereinafter also referred to as the receiving position) to the upper position of the lower mold 61 (hereinafter referred to as the transfer position) by the transfer unit 40. To be called). The transfer unit 40 of the present embodiment has a drive source 41, and the support member 30 moves from a receiving position to a transfer position along a rail (not shown) by the driving force of the drive source 41. However, the receiving position and the transfer position may be the same position or different positions.

  The manufacturing apparatus of the present invention further includes a detection unit 51 as detection means. This detection unit 51 detects the temperature of the molten glass lump FG on the receiving surface 33, and the detected temperature is input in advance. Based on the glass composition, the viscosity η of the molten glass FG is calculated. Then, the detection unit 51 transmits the viscosity η data to the control unit 53.

  The control unit 53 has a transfer control unit as transfer control means, and this transfer control unit controls the transfer unit 40 based on the viscosity η of the received data. Specifically, while the logarithmic log η of the viscosity (dPa · s) is at least less than 1, the molten glass lump FG is not transferred to the mold 60, and the log η is an arbitrary value of 1 or more and 6.65 or less. At that point, the molten glass block FG is transferred to the mold 60. The molten glass block FG having a log η of 1 or more and 6.65 or less has an appropriate viscosity, so that the molten glass block FG is not easily damaged regardless of the impact at the time of transfer and can be quickly formed. Therefore, the consumption of the mold 60 can be suppressed. The lower limit of log η is more preferably 1.2, and most preferably 1.5. Further, the upper limit of log η is more preferably 6.5, and most preferably 6.0.

  In this embodiment, the temperature is measured for each molten glass block FG and the drive of the support member 30 is controlled. If the time to reach the above viscosity is already known, the temperature is determined based on that time. Then, the driving of the support member 30 may be controlled. In that case, the detection unit 51 and the control unit 53 may not be provided.

  As shown in FIG. 1, the transfer unit 40 preferably drops the molten glass lump FG from the surface 33 onto the mold 60. Unlike a mode in which the molten glass lump FG is held and transferred using any member, since no member that contacts the molten glass lump FG is interposed, contamination of the molten glass lump FG can be suppressed. In such an embodiment, there is a concern about the breakage of the molten glass lump FG due to the drop impact on the mold 60, but in the present invention, the transfer is performed when the viscosity of the molten glass lump FG falls within a predetermined range. Even if the molten glass block FG is broken, it can be greatly reduced.

  In the support member 30 of this embodiment, the receiving surface 33 can be divided into two or more (in FIG. 1, it is divided into two divided surfaces 331 and 333 by the divided formation surface 34), and is divided into two or more by the arm 43. Division and integration can be repeated. The arm 43 is driven by a drive source 41, and when performing transfer according to the above-described control, the receiving surface 33 is divided and the molten glass lump on the receiving surface 33 is dropped. The split forming surface 34 is preferably formed at the center of the receiving surface 33 as shown in FIG. 1 in terms of being easy to drop while maintaining the horizontal posture of the molten glass block FG, but is not limited thereto. Absent.

  Further, the receiving surface 33 shown in FIG. 1 is made of a porous member. Gas supply pipes 37a and 37b are provided at the bottom of the porous member, and these gas supply pipes 37a and 37b supply gas from a gas supply source (not shown) to the porous member. Here, since the periphery of the porous member is covered with the outer wall 35, the supplied gas is ejected from the receiving surface 33 to the molten glass. Thereby, since a molten glass floats from the receiving surface 33, the situation where a molten glass adheres to the receiving surface 33 can be suppressed.

  However, in such a mode in which the gas is ejected to the molten glass, the molten glass is rapidly cooled by the gas, and it becomes difficult to set the viscosity at the time of transfer to the aforementioned range, or between the surface and the center of the molten glass. There is a concern that the temperature difference becomes excessive, and cracks and the like during press molding described later occur. Therefore, it is preferable that the manufacturing apparatus further includes a temperature control device that controls the temperature of the gas supplied to the gas supply pipe. Thereby, since the temperature-controlled gas is ejected from the receiving surface 33, the rapid cooling of the molten glass is suppressed, and the above-mentioned concerns can be solved. The gas supply pipes 37a and 37b, the gas supply source, and the temperature control device constitute gas supply means.

  The control unit 53 of the present embodiment preferably includes a supply control unit as a supply control unit, and the supply control unit is based on the temperature detected by the detection unit 51 and is a gas supply source and / or a temperature control device. To control. Specifically, the supply control unit performs control so that the temperature of the molten glass gob FG decreases at a rate of −700 ° C./min or more and −100 ° C./min or less. Thereby, while the viscosity of the molten glass lump FG at the time of transfer can be easily set to the above-mentioned range, the crack at the time of the press molding resulting from the temperature difference of the surface and center of molten glass FG can be suppressed reliably. The lower limit of the temperature drop rate of the molten glass gob FG is more preferably −650 ° C./min, and most preferably −600 ° C./min. Further, the upper limit of the temperature decrease rate of the molten glass gob FG is more preferably −120 ° C./min, and most preferably −150 ° C./min.

  Here, the rate of temperature decrease is an average value in an arbitrary period from the time when the molten glass is received by the receiving surface 33 to the time when the molten glass lump FG is transferred from the receiving surface 33 to the mold 60. . Therefore, the detection unit 51 detects the temperature of the molten glass block FG at any two or more locations from the receiving position to the transfer position.

  In this way, the molten glass block FG is transferred from the receiving surface 33 to the mold 60. The mold 60 of the present embodiment has a lower mold 61 and an upper mold 63, and the molten glass block FG is installed on the installation surface 611 of the lower mold 61. Here, the upper mold 63 has a press surface 631, and the press surface 631 is disposed so as to face the installation surface 611 on which the molten glass block FG is installed. When the upper die 63 approaches the lower die 61, the molten glass block FG is pressed by the press surface 631 and the installation surface 611, and an optical element GC such as an optical lens is manufactured.

  In the present embodiment, the mold 60 further includes a body mold 65, and the body mold 65 surrounds the lower mold 61 and the upper mold 63 to define the approach and separation trajectories. As a result, the approaching and separation trajectories of the lower die 61 and the upper die 63 are constant, so that the pressing conditions are uniform, and the quality of the optical element can be made more constant. The approach and separation trajectories are generally in the axial direction of the lower die 61 and the upper die 63 as shown in FIG. 1, but are not limited thereto.

  Moreover, the trunk | drum 65 of this embodiment is a cylindrical member. The body die 65 is placed on the flange portion 613 of the lower die 61 and supports the flange portion 633 of the upper die 63 when the upper die 63 moves downward, thereby lowering the lower die 61. And the impact at the time of the collision of the upper mold | type 63 is relieved.

  The above mold 60 is preferably heated by a heating mechanism (not shown). Since the molten glass block FG is cooled by the outside air in the process until transfer, it has a temperature gradient from the surface having the lowest temperature to the center having the highest temperature. However, when it is transferred to the mold 60, the molten glass block FG is heated from its surface by the installation surface 611 and the press surface 631, so that the temperature gradient is quickly eliminated. For this reason, a preferable state for performing press molding, that is, a state where the temperature is uniform over the entire state can be achieved in a short period of time, which is advantageous in that the press molding time can be greatly shortened.

  According to the above manufacturing apparatus, since it is transferred when the viscosity of the molten glass lump FG falls within a predetermined range, the molten glass lump FG is hardly damaged during the transfer, and consumption of the mold 60 can be suppressed. An optical element manufactured using such a manufacturing apparatus is included in the present invention.

<Optical element manufacturing method>
An optical element manufacturing method according to an embodiment of the present invention will be described with reference to the above manufacturing apparatus. In the manufacturing method of the optical element, the molten glass is received and held by the receiving surface 33 of the support member 30 to form a molten glass lump FG, and the molten glass lump FG on the receiving surface 33 is put into the press molding die 60. And transport.

  In the production method of the present invention, the molten glass block FG is transferred when the logarithmic log η of its viscosity (dPa · s) becomes 1 or more and 6.65 or less. Thereby, it is hard to be damaged irrespective of the impact at the time of transfer, and since the temperature is appropriately reduced, the consumption of the mold 60 can be suppressed.

  As shown in FIG. 1, the molten glass block FG is preferably transferred by dropping it from the receiving surface 33 onto the mold 60. Since no member that contacts the molten glass block FG is interposed, contamination of the molten glass block FG can be suppressed. Moreover, in this invention, since it transfers when the viscosity of the molten glass lump FG becomes a predetermined range, even if it is a failure | damage of the molten glass lump FG by a drop impact, it can reduce significantly.

  The support member 30 is preferably made of a porous member having a receiving surface 33 that can be divided into two or more, and the temperature-controlled gas is ejected from the receiving surface 33 to float the molten glass lump FG. Thereby, since the temperature-controlled gas is ejected from the receiving surface 33 while suppressing the situation where the molten glass adheres to the receiving surface 33, the rapid cooling of the molten glass FG is suppressed, and the above-described concerns can be solved. In addition, the transfer of the molten glass block FG in this mode is performed by dividing the receiving surface 33 and dropping it.

  Here, it is preferable to eject the gas so that the temperature of the molten glass block decreases at a rate of −700 ° C./min or more and −100 ° C./min or less. Thereby, while the viscosity of the molten glass lump FG at the time of transfer can be easily set to the above-mentioned range, the crack at the time of the press molding resulting from the temperature difference of the surface and center of molten glass FG can be suppressed reliably.

  Next, in the method for manufacturing an optical element, the molten glass block FG transferred from the receiving surface 33 to the mold 60 is press-molded. Specifically, the press surface 631 is disposed so as to face the installation surface 611 on which the molten glass block FG is installed, and the upper die 63 approaches the lower die 61. Then, the molten glass block FG is pressed by the press surface 631 and the installation surface 611, and an optical element GC such as an optical lens is manufactured.

  Since the above-described optical element manufacturing method is transferred when the viscosity of the molten glass block FG reaches a predetermined range, the need for reheating is low and the transfer time can be shortened, and the molten glass block FG is transferred to the mold at an optimum temperature. Therefore, the consumption of the mold can be suppressed and the molding time can be shortened. Moreover, the optical element manufactured by this manufacturing method is useful in an optical instrument. A method for manufacturing an optical apparatus using such an optical element is included in the present invention.

  The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

It is a figure which shows the procedure of the optical element manufacturing method using the optical element manufacturing apparatus 10 which concerns on one Embodiment of this invention.

Explanation of symbols

30 Supporting member 33 Receiving surface 40 Transfer section (transfer means)
51 Detection part (detection means)
53 Control unit (transfer control means, supply control means)
60 Mold 61 Lower mold 63 Upper mold FG Molten glass block GC Optical element

Claims (10)

Receiving and holding the molten glass at the receiving surface of the support member, forming a molten glass lump,
When the logarithm log η of the viscosity (dPa · s) is 1 or more and 6.65 or less, the molten glass lump on the receiving surface is transferred into a press molding die,
The manufacturing method of the optical element which has the process of press-molding the molten glass lump in the said metal mold | die.   The method according to claim 1, wherein the molten glass lump is transferred by dropping the molten glass lump from the receiving surface to the mold. The support member is made of a porous member whose receiving surface can be divided into two or more,
The manufacturing method of Claim 1 or 2 which ejects the temperature-controlled gas from the said receiving surface, and float-molds a molten glass lump.   The manufacturing method of Claim 3 which ejects the said gas so that the temperature of a molten glass lump may fall at the rate of -700 degrees C / min or more and -100 degrees C / min or less.   The manufacturing method of the optical instrument using the optical element manufactured with the manufacturing method in any one of Claim 1 to 4. A support member having a receiving surface for receiving molten glass, a press molding apparatus having a mold for press molding, and a transfer means for transferring a molten glass lump formed by being held by the receiving surface into the mold, An optical element manufacturing apparatus comprising:
Detecting means for detecting the temperature of the molten glass lump and calculating the viscosity;
And a transfer control means for controlling the transfer means based on the viscosity calculated by the detection means.   The manufacturing apparatus according to claim 6, wherein the transfer unit drops the molten glass lump from the receiving surface onto the mold. The receiving surface is made of a porous member that can be divided into two or more,
The said manufacturing apparatus is a manufacturing apparatus of Claim 6 or 7 further provided with the gas supply means which ejects the temperature-controlled gas from the said receiving surface.   The manufacturing apparatus according to claim 8, further comprising supply control means for controlling the gas supply means based on the temperature detected by the detection means.   An optical device manufacturing apparatus for manufacturing an optical device using the optical element manufactured by the manufacturing device according to claim 6.

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