JP2010059014A - Method of producing glass lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a glass lens by a drop method, having an excellent conforming product rate and a high production efficiency. <P>SOLUTION: The method of producing the glass lens has a molding process for molding the glass lens by dropping molten glass to a lower die and pressurizing the dropped molten glass by an upper die facing the lower die. The molding process includes a separation and collection process in which molded glass lenses are separated into two and collected, the one taken out from the upper die as a first glass lens and the one taken out from the lower die as a second glass lens. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a glass lens.

  Optical elements such as pickup lenses for next-generation DVDs and camera lenses for mobile phones are required to be smaller as well as smaller. These fine glass optical elements can be manufactured by a method in which a glass gob (preform) placed in a mold is heated to high temperature under deoxidation (reheat method), and a molten glass droplet is received by the mold. A method of directly pressing (droplet method) is known.

  The reheat method is a method in which a glass gob (preform) processed in advance to a predetermined volume by a method such as polishing is supplied into a mold and then pressed while simultaneously heating the mold and the preform.

  The droplet method is a method in which molten glass is dropped from the lower end of a nozzle extending from a glass melting furnace, the dropped molten glass is received by a mold disposed below the nozzle, and then pressed by the other mold facing the nozzle. is there. This method is a molding method with a short molding time and high productivity.

  In the above reheating method, the following has been proposed as a method for efficiently recovering an optical element such as a glass lens after completion of molding. Patent Document 1 has a sensor that detects whether an optical element is attached to the upper mold, and when the sensor detects the optical element when molding is completed, waits for a predetermined time until the optical element falls to the lower mold side, or A method of cooling the upper mold and forcibly leaving the optical element on the lower mold side has been proposed.

  Patent Document 2 proposes the following. The upper mold, lower mold, and body mold are configured, and the diameter around the tip of the upper mold tip side region is made smaller than the diameter of the inner periphery of the body mold, and communicates with the cavity for molding the glass molded body (optical element). A space is formed. At the time of mold opening after molding, peeling of the glass molded body from the upper molding surface of the upper mold is promoted by introducing compressed gas into the space.

Patent Document 3 proposes the following. It consists of an upper mold, a lower mold, and a body mold. The body mold is fitted to the lower mold and the upper mold, respectively, and the upper mold and the lower mold are positioned, and the inner surface of the trunk mold is pushed down when pressed. Become an upper guide. A convex portion is formed on the inner peripheral surface of the barrel mold so as to project from the inner peripheral surface to a position covering at least a part of the end portion of the upper surface of the lens to be molded. This convex portion prevents the formed lens from adhering to the upper mold and remaining.
JP-A-5-43259 JP 2002-20130 A JP-A-8-109031

  The method of recovering an optical element such as a molded lens described in Patent Documents 1 to 3 from the mold increases manufacturing efficiency by automating the reliable handling of the optical element. Therefore, the molded optical element is always on the lower side. When a complicated mold configuration is required so as to remain in the mold, or when the molded optical element adheres to the upper mold, the apparatus waits until the optical element falls from the upper mold and can be collected from the lower mold. For this reason, when it sees as the whole manufacturing process, it cannot necessarily be said that manufacturing efficiency is good.

  In a glass lens which is an optical element molded by the droplet method, the glass lens recovered from the state attached to the upper mold and the glass lens recovered from the state attached to the lower mold have two optical performances. I found out that For this reason, when the molded glass lens is collected from both the upper and lower molds, or attached to the upper mold, the glass lens is left on the lower mold side in each method as in Patent Documents 1 to 3, If it adheres to the lower mold, if it is recovered from the lower mold side as it is, two types of glass lenses with different optical performances will be mixed, and handling of the glass lenses in the subsequent processes will be complicated, resulting in reduced production efficiency. Problem arises. In addition, when only one glass lens with two-divided optical performance is adopted as a product, the yield rate is lowered and the production efficiency is lowered.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for manufacturing a glass lens with a good product rate by the droplet method and a high manufacturing efficiency.

  Said subject is solved by the following structures.

1. In the method for producing a glass lens, the molten glass is dropped on a lower mold, the molten glass dropped on the upper mold facing the lower mold is pressed, and a glass lens is molded.
In the molding step, the collected glass lens is separated into two parts and collected as a first glass lens when taken out from the upper mold and as a second glass lens when taken out from the lower mold. The manufacturing method of the glass lens characterized by having a process.

2. The molding step includes
When the glass lens is molded and the lower mold and the upper mold are opened and the glass lens is taken out, it has a detection step of detecting whether the glass lens is attached to the upper mold or the lower mold,
2. The method for producing a glass lens according to 1, wherein the glass lens molded based on the result of the detection step is collected in the sorting and collecting step.

3. Having a post-processing step of performing post-processing on the glass lens obtained by the molding step;
3. The method of manufacturing a glass lens according to 1 or 2, wherein the post-processing includes different heat treatments for the first glass lens and the second glass lens that are separated and collected.

  According to the method for manufacturing a lens of the present invention, it is possible to provide a method for manufacturing a lens with a good yield rate by the droplet method and a high manufacturing efficiency.

  Although the present invention will be described based on the illustrated embodiment, the present invention is not limited to the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. FIG. 1 is a flowchart showing an example of a method for producing a glass lens which is a glass molded body of the present invention. 2 to 4 are schematic views showing an example of a glass lens manufacturing apparatus used in this embodiment. FIG. 2 shows a state in the dropping step, FIG. 3 shows a state in the pressurizing step, and FIG. Shows a separate collection step for collecting the molded lens. In FIG. 4, the portion where the molten glass droplet is dropped is omitted.

  First, the configuration of the glass lens manufacturing apparatus 10 used in the present embodiment will be described with reference to FIGS. As shown in FIGS. 2 and 3, the glass lens manufacturing apparatus 10 includes a melting tank 21 for storing molten glass 22, a dropping nozzle 23 connected to the lower part of the melting tank 21, and a bottom for receiving molten glass droplets 20. The upper mold 12 that pressurizes the molten glass droplet 20 together with the mold 11 and the lower mold 11 is provided.

  Further, as shown in FIG. 4, the manufacturing apparatus 10 presses the molten glass droplet 20 with the lower mold 11 and the upper mold 12 and then opens the lower mold when the lower mold 11 and the upper mold 12 are opened. A sensor 31 and a sensor 32 that can detect whether the glass lens 25 is attached to the 11 or the upper mold 12 are provided. In addition, a lower mold recovery machine 41 for taking out and collecting the glass lens 25 (second glass lens) attached to the lower mold 11 and a glass lens 25 (first glass lens) attached to the upper mold 12 are provided. And an upper mold collecting machine 42 for taking out and collecting.

  When the glass lens adheres to the lower mold 11, the sensor 31 detects, and when the glass lens adheres to the upper mold 12, the sensor 32 detects. Based on the detection results of the sensors 31 and 32, the glass lens 25 attached to the lower mold 11 or the upper mold 12 is made of glass using either the lower mold recovery machine 41 or the upper mold recovery machine 42. The lens 25 is taken out, and the lower mold 11 or the upper mold 12 is collected into two parts and stored in a pallet (not shown) or the like.

  The lower mold 11 is pressure-formed by a driving means (not shown) for receiving the molten glass droplet 20 below the dropping nozzle 23 (dropping position P1) and facing the upper mold 12. It is configured to be movable between a position for pressing (pressing position P2).

  The upper mold 12 is configured to be movable in the vertical direction by driving means (not shown) so that the lower mold 11 and the upper mold 12 are pressure-molded at a predetermined interval or with a predetermined pressure. .

  In the present embodiment, only the upper die 12 moves in the pressurizing direction, but the present invention is not limited to this, and the upper die 12 is fixed and only the lower die 11 is pressurized. It is good also as a structure which moves to a direction, and it is good also considering both the lower mold | type 11 and the upper mold | type 12 as a movable type.

  The materials of the lower mold 11 and the upper mold 12 are heat-resistant alloys (stainless steel, etc.), super hard materials mainly composed of tungsten carbide, various ceramics (silicon carbide, silicon nitride, aluminum nitride, etc.), composite materials containing carbon, etc. As a molding die for pressure-molding the glass lens, it can be appropriately selected from known materials. The lower mold 11 and the upper mold 12 may be made of the same material, or may be made of different materials.

  It is also preferable to provide a coating layer on the surface in order to improve the durability of the lower mold 11 and the upper mold 12 and prevent fusion with the molten glass droplet 20. There are no particular restrictions on the material of the coating layer. For example, various metals (chromium, aluminum, titanium, etc.), nitrides (chromium nitride, aluminum nitride, titanium nitride, boron nitride, etc.), oxides (chromium oxide, aluminum oxide, etc.) , Titanium oxide, etc.) can be used. The method for forming the coating layer is not limited and may be appropriately selected from known film forming methods. For example, vacuum deposition, sputtering, CVD, etc. are mentioned.

  The lower mold 11 and the upper mold 12 are configured to be heated to a predetermined temperature by a heating unit (not shown). As the heating means, known heating means can be appropriately selected and used. For example, a cartridge heater that is used by being embedded inside the member to be heated, a sheet heater that is used while being in contact with the outside of the member to be heated, an infrared heating device, a high-frequency induction heating device, or the like can be used.

  The steps of the lens manufacturing method according to the present invention will be described in order according to the flowchart shown in FIG. Steps S11 to S18 are referred to as molding steps.

  First, the lower mold 11 and the upper mold 12 are each heated to a predetermined temperature (step S11). The predetermined temperature may be any temperature that can form a good transfer surface on the glass lens 25. Generally, when the temperature of the lower mold 11 and the upper mold 12 is too low, it becomes difficult to form a highly accurate transfer surface.

  On the contrary, it is not preferable to raise the temperature more than necessary because fusion with glass tends to occur or the life of the lower mold 11 and the upper mold 12 may be shortened. Usually, the temperature is set in the range of Tg−200 ° C. to Tg + 100 ° C., where Tg is the glass transition temperature of the glass to be pressed. Actually, the appropriate temperature varies depending on various conditions such as the type of glass, the shape and size of the glass lens 25, the material of the lower mold 11 and the upper mold 12, and the type of coating film. Is preferably obtained. The heating temperature of the lower mold 11 and the upper mold 12 may be the same temperature or different temperatures.

  In the present embodiment, the lower mold 11 and the upper mold 12 are heated to predetermined temperatures, respectively, and then the molten glass droplet 20 is dropped and pressure-molded, so that the heating temperature of the lower mold 11 and the upper mold 12 is kept constant. A series of steps can be carried out while keeping.

  Furthermore, a plurality of glass lenses 25 can be repeatedly manufactured while keeping the heating temperature of the lower mold 11 and the upper mold 12 constant. Therefore, since it is not necessary to repeat the temperature rise and cooling of the lower mold 11 and the upper mold 12 every time one glass lens 25 is manufactured, an optical element can be manufactured efficiently in a very short time.

  Here, keeping the heating temperature of the lower die 11 and the upper die 12 constant means that the target set temperature in the temperature control for heating the lower die 11 and the upper die 12 is kept constant. Therefore, it is not intended to prevent temperature fluctuation due to contact with the molten glass droplet 20 during each process, and such temperature fluctuation is allowed.

  Next, the lower die 11 is moved to the dropping position P1 (step S12), and the molten glass droplet 20 is dropped on the lower die 11 (dropping step S13) (see FIG. 2).

  The melting tank 21 is heated by a heater (not shown), and a molten glass 22 is stored inside. A dropping nozzle 23 is provided in the lower part of the melting tank 21, and the molten glass 22 passes through a flow path provided inside the dropping nozzle 23 by its own weight and accumulates at the tip portion by surface tension. When a constant mass of molten glass accumulates at the tip of the dropping nozzle 23, the molten glass droplet 20 is naturally separated from the tip of the dropping nozzle 23, and a constant mass of molten glass droplet 20 drops downward.

  The mass of the molten glass droplet 20 to be dropped can be adjusted by the outer diameter of the tip of the dropping nozzle 23, the heating temperature, etc., and depending on the type of glass, the molten glass droplet 20 of about 0.1 g to 2 g should be dropped. Can do. Further, the dropping interval of the molten glass droplets 20 can be adjusted by the inner diameter, length, heating temperature, etc. of the dropping nozzle 23. Therefore, by appropriately setting these conditions, it is possible to drop molten glass droplets 20 having a desired mass at desired intervals.

Further, instead of dropping the molten glass droplet 20 directly from the dropping nozzle 23 onto the lower mold 11, as shown in FIG. 5, as shown in FIG. 11 may be dropped. When the molten glass droplet 20 dropped from the dropping nozzle 23 collides with the volume adjusting member 18, a part of the collided molten glass droplet 20 becomes a microdroplet 24 and passes through the through-hole 19, and is disposed below. Drip onto the mold 11. This method, for example, it is possible to manufacture a ^{1 mm} 3 100 mm ³ such fine glass lens 25. Further, it is preferable to change the diameter of the through-hole 19 because the volume of the molten glass droplet can be adjusted without replacing the dropping nozzle 23 and various glass lenses 25 can be efficiently manufactured.

  There is no restriction | limiting in particular in the kind of glass which can be used, A well-known glass can be selected and used according to a use. Examples thereof include optical glasses such as borosilicate glass, silicate glass, phosphate glass, and lanthanum glass.

  Next, the lower mold | type 11 is moved to the pressurization position P2 (process S14), the upper mold | type 12 is driven below, and the molten glass droplet 20 is pressure-molded (pressurization process S15) (refer FIG. 3).

  The molten glass droplet 20 is cooled and solidified by the contact with the lower mold 11 and the upper mold 12 during the pressurizing step S <b> 15 and becomes the glass lens 25. After the glass lens 25 is cooled to a temperature at which the shape of the formed transfer surface does not collapse even when the pressure is released, the pressure is released. Although it depends on the type of glass, the size and shape of the glass lens, the required accuracy, etc., it is usually sufficient that the glass is cooled to a temperature near the Tg of the glass.

  The upper mold 12 is moved upward and retracted (mold opening process S16). After the mold opening step S <b> 16, the glass lens is attached to the retracted upper mold 12 or attached to the lower mold 11. Whether the glass lens is attached to the upper mold 12 or the lower mold 11 is detected by the sensors 31 and 32 (detection step S17). The sensor 31 and the sensor 32 include, for example, a light projecting element and a light receiving element, and light emitted from a light projecting element such as an LED hits a side portion of the glass lens 25, and the light receiving element receives the reflected light so that the glass is received. A reflective sensor that detects the presence / absence of the lens 25 is included, but the present invention is not limited to this.

  Depending on the detection results of the sensors 31 and 32, the glass lens 25 is attached to the bottom using the lower mold recovery machine 41 or the upper mold recovery machine 42 shown in FIGS. 4 (a) and 4 (b). The glass lens 25 is collected from either the mold 11 or the upper mold 12, and from which mold the glass lens 25 is collected is separated and stored in a container such as a pallet (not shown) (sorting and collecting step S18).

  The lower mold recovery machine 41 and the upper mold recovery machine 42 have, for example, a holding unit that holds a portion that is not an optical surface of the glass lens 25 by vacuum suction or the like at the tip of an arm of a robot or the like, and the glass lens 25 is attached The glass lens 25 is peeled off from the upper mold 12 or the lower mold 11, removed from the mold, and stored in a predetermined separated container such as a pallet.

  4 (a) and 4 (b), the manufacturing apparatus 10 includes two recovery machines, one for the lower mold and the other for the upper mold, but the holding unit that holds the glass lens 25 at the tip of the arm is moved up and down. It is possible to change the direction by rotation or the like, and to collect the glass lens 25 from either the lower mold 11 or the upper mold 12 and store it in a separated container.

  The optical performance of the glass lens 25 molded as described above and separated and collected from the lower mold 11 and the upper mold 12 is measured using a commercially available interferometer (for example, model DVD400Pro manufactured by Zygo Co., Ltd.). Then, the transmitted wavefront aberration measured using a commercially available analysis software (for example, MetroPro manufactured by Zygo Corporation) was developed into a Zernike polynomial and evaluated. As a result, it has been found that the optical performance of the glass lens 25 is divided into, for example, a third-order spherical aberration amount corresponding to the recovered lower mold 11 and upper mold 12.

  As described above, the glass lens 25 manufactured by press molding is, for example, a part in which molten glass droplets are dropped on the lower mold 11 and in contact with the lower mold 11 at this point in the manufacturing process. Then, the cooling starts from the upper mold 12, and then the upper mold 12 pressurizes the upper part of the molten glass droplet to apply the cooling from the portion in contact with the upper mold 12. Further, it is considered that different restraint states occur between the glass lens 25 to be molded and the upper and lower mold surfaces depending on the degree of adhesion between the molten glass droplet and the lower mold 11 and the upper mold 12. In particular, it is considered that depending on the degree of adhesion between the molten glass droplet and the lower mold 11 and the upper mold 12, it is determined which of the upper and lower molds the glass lens 25 is attached to after the mold opening. From these, the state of the internal stress of the glass lens recovered from the lower mold 11 and the upper mold 12 is largely divided into two corresponding to the recovered mold, and the state of the internal stress is reflected in the optical performance described above. I guess.

  It has been found that the internal stress in a glass lens by press molding can be relaxed by an annealing treatment after molding. Therefore, the recovered glass lens 25 is subjected to an annealing process as a post-process depending on the state of internal stress depending on whether it is recovered from the state of being attached to either the upper or lower mold, and by relieving stress strain, A glass lens 25 having a desired optical performance can be obtained.

  As annealing conditions, for example, temperature setting and heating time when heating at a constant temperature, temperature rising time until reaching a certain temperature from room temperature (temperature gradient at the time of heating), cooling to return from the heated constant temperature to room temperature There are parameters such as time (temperature gradient during cooling).

  In order to obtain a desired optical performance in a certain glass lens, annealing treatment conditions are appropriately determined by an experiment using each glass lens. Roughly, the heating time is determined based on the size of the glass lens, and the heating temperature is determined by the lens material. Furthermore, considering the lens shape such as biconvex, plano-convex, meniscus, and the combination of lens material and mold material (particularly the material of the mold surface that contacts the lens), the annealing treatment was actually performed. To determine the optimum annealing conditions.

  If the stress strain remaining in the glass lens after mold opening is relatively small, the annealing treatment is not provided separately in the post-treatment process as described above, and the heating during the coating treatment for providing the antireflection film provided on the lens surface is performed. It may also be used to perform an annealing process for removing stress strain. In this case as well, it is necessary to set the heating conditions according to the optical performance of the separately collected lens at the time of the coating process as described above.

  In the glass lens manufacturing method described so far, the glass lens is recovered by performing different annealing treatment on the glass lens separately collected from the lower mold 11 and the upper mold 12 depending on which of the upper and lower molds is recovered. Regardless of the upper and lower molds, good optical performance can be provided. Therefore, a glass lens can be efficiently manufactured with a good yield rate.

  In addition, the manufacturing method of the glass lens 25 concerning this invention may include another process other than having demonstrated here. For example, you may have the process of wash | cleaning before collect | recovering the collect | recovered glass lens 25 to a post-processing process, the process of cleaning the lower mold | type 11 and the upper mold | type 12 after collect | recovering the glass lens 25, etc.

  Moreover, in the manufacturing method of said glass lens 25, as a more preferable form, the detection process which detects whether the glass lens 25 has adhered to upper and lower type | molds is provided, and it collects by collect | recovering based on the detection result. The work efficiency is improved, but the detection process is not provided, and the recovery machines 41 and 42 may be recovered toward the recovery of the glass lens 25 in any of the upper and lower molds after opening the mold.

  As described so far, by separately collecting the glass lens 25 from the upper and lower molds, the glass lens 25 having two different optical performances can be efficiently used in the subsequent steps. As a method of efficiently using the separately collected glass lens 25, there may be a case where desired optical performance is obtained by combining the glass lens 25 with another lens, for example, in addition to a method of performing different heat treatments.

  Specifically, the glass lens 25 is combined with another lens having an optical performance that cancels the optical performance of the glass lens 25, and the glass lens 25 is combined with the other lens. The desired air performance is obtained by adjusting the air interval to cancel the optical performance of the glass lens 25 divided into two. Thus, when using the glass lens 25, separating and collecting the glass lens 25 into two from the upper and lower molds, the glass lens 25 having different optical performance divided into two can be used efficiently in the subsequent steps. .

Example 1
A glass lens was manufactured using the manufacturing apparatus 10 described so far. This will be described with reference to FIGS. The manufactured glass lens 25 was a biconvex aspherical lens having an outer diameter of 4 mm, an effective optical diameter of 3 mm, and a center thickness of 2.1 mm. As the glass material, silica glass having a Tg of 480 ° C. and a refractive index nd of about 1.6 was used.

  As the materials of the upper mold 12 and the lower mold 11, superhard materials mainly composed of tungsten carbide were used. The mold was heated so that the surface temperature of the molding surface of the mold was 400 ° C. for the upper mold 12 and 350 ° C. for the lower mold 11.

  The lower mold 11 first moves to a dropping position P1 immediately below a dropping nozzle 23 made of platinum for dropping the molten glass droplet 20, and the molten glass droplet 20 dropped by the volume adjusting member 18 provided with the through hole 19. Is received by the lower mold 11 (see FIG. 5). After receiving the microdrops 24 by the lower mold 11, the lower mold 11 moves to a pressure position P <b> 2 below the upper mold 12 (see FIG. 3). 10 seconds after the lower mold 11 reaches the pressing position P2, the upper mold 12 moves in the vertical direction, and the molten glass droplet 20 in the lower mold 11 is pressed. The moving speed of the upper die 12 was 10 mm / sec, the pressing pressure of the upper die 12 was 0.49 kN, and the time for maintaining the pressing pressure was 10 seconds.

  After a predetermined time has elapsed, the upper mold 12 is separated from the lower mold 11 to complete the press. Thereafter, the presence or absence of the lens is detected by the sensor 31 and the sensor 32 that determine whether the molded glass lens 25 is attached to the upper mold 12 or the lower mold 11, and the detected glass lens 25 adheres. The glass lens 25 is recovered from the mold using the recovery machine 41 or the recovery machine 42 provided with a vacuum suction type holding unit from the mold (see FIG. 4). The collected glass lens 25 was stored in a pallet separately depending on whether it was collected from the upper mold 12 or the lower mold 11. As a result of molding 100 glass lenses 25, 60 glass lenses 25 were collected from the upper mold 12, and 40 glass lenses 25 were collected from the lower mold 11.

  After being collected on a pallet and fully acclimatized to room temperature, the optical performance of the glass lens 25 was measured and evaluated. The optical performance of the glass lens 25 was measured using a wavefront aberration using an interferometer (model DVD400Pro, manufactured by Zygo Corporation), and then measured using an analysis software (manufactured by Zygo Corporation, MetroPro). Aberrations were obtained by expanding into Zernike polynomials. As a result, the third-order spherical aberration amount (SA3) at the measurement wavelength of 405 nm was in the range of 16 mλrms to 20 mλrms and in the range of 6 mλrms to 10 mλrms in the glass lens 25 recovered from the upper mold 12 and the lower mold 11. . Various required aberration values other than the amount of third-order spherical aberration were within a good range with no practical problems.

  The glass lens 25 separated and collected was subjected to annealing treatment (heating treatment) for removing internal stress (strain). The annealing process is performed with different heating characteristics depending on whether the lens is recovered from the upper mold 12 or the lower mold 11. The heating characteristic A shown in FIG. 6 is applied to the glass lens 25 recovered from the lower mold 11. The characteristic B was performed on the glass lens 25 collected from the upper mold 12. Note that conditions such as temperature, time, and temperature gradient, which are the characteristics of annealing treatment, were determined in advance by experiments and the like in consideration of the size of the lens, material, and the like.

  When the optical performance of the lens after the annealing treatment was measured again by the same method as described above, the SA3 of the glass lens 25 recovered from the upper mold 12 and the lower mold 11 was in the range of −2.0 mλrms to 1.8 mλrms, respectively. It was in the range of 1.5 mλrms to 1.5 mλrms, and it was confirmed that all 100 pieces could be included in a numerical range having no practical problem. It was also confirmed that other required aberration values are within a good range. Thereafter, an antireflection film comprising a multilayer film mainly composed of magnesium fluoride and alumina was applied to the glass lens 25 to complete the product.

As described above, the molten glass dropped on the lower mold is pressed with the upper mold to form a glass lens, the upper mold and the lower mold are opened, and then the molded glass lens is taken out from the lower mold and the upper mold. Separated and collected into two cases when removed from the mold. As a result, glass lenses having different amounts of third-order spherical aberration can be collected in a separated state, and the subsequent transition to annealing for obtaining desired optical performance can be performed efficiently. In addition, by performing different annealing treatments on the glass lens collected from the upper mold and the glass lens collected from the lower mold, any glass lens could be made a non-defective product. By separating and collecting the molded glass lenses into two by the mold from which the glass lenses are taken out, both of the separately collected glass lenses can be made non-defective, resulting in a good product rate and good manufacturing efficiency. Was made.
(Comparative Example 1)
A glass lens was manufactured using the same manufacturing apparatus 10 as in Example 1. When recovering the molded glass lens, it was stored in the pallet without being classified depending on whether it was recovered from the upper mold 12 or the lower mold 11. A glass lens was molded and collected in the same manner as in Example 1 except that this fractional collection was not performed.

  To move to the annealing process to obtain the desired optical performance, one glass lens is taken out from the pallet in a state where glass lenses having two optical performances are mixed and cannot be separated visually. It was necessary to measure and sort the optical performance using analysis software, and the manufacturing efficiency was low due to the time spent on sorting.

  In addition, it is conceivable to anneal one of the two heating characteristics A or B without separating the glass lens by measuring the optical performance, but it is not possible to obtain the desired optical performance. Occurs. The glass lens that has not been able to obtain the desired optical performance is subjected to heat treatment again, melted and reused, or discarded. In any case, the yield rate is reduced and the production efficiency is also reduced.

It is a figure which shows the flowchart which shows an example of the manufacturing method of a glass lens. It is a figure which shows an example of the manufacturing apparatus of a glass lens (dripping process). It is a figure which shows an example of the manufacturing apparatus of a glass lens (pressurization process). It is a figure which shows an example of the manufacturing apparatus of a glass lens (separation collection process). It is a figure which shows another example of the manufacturing apparatus of a glass lens (dripping process). It is a figure which shows the heating characteristic in the annealing process of the glass lens in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Manufacturing apparatus 11 Lower mold | type 12 Upper mold | type 20 Molten glass droplet 21 Molten tank 22 Molten glass 23 Dripping nozzle 25 Glass lens P1 Dropping position P2 Pressurization position 31, 32

Claims (3)

In the method for producing a glass lens, the molten glass is dropped on a lower mold, the molten glass dropped on the upper mold facing the lower mold is pressed, and a glass lens is molded.
In the molding step, the collected glass lens is separated into two parts and collected as a first glass lens when taken out from the upper mold and as a second glass lens when taken out from the lower mold. The manufacturing method of the glass lens characterized by having a process. The molding step includes
When the glass lens is molded and the lower mold and the upper mold are opened and the glass lens is taken out, it has a detection step of detecting whether the glass lens is attached to the upper mold or the lower mold,
The method for manufacturing a glass lens according to claim 1, wherein the glass lens molded based on the result of the detection step is collected in the sorting and collecting step. Having a post-processing step of performing post-processing on the glass lens obtained by the molding step;
3. The glass lens manufacturing method according to claim 1, wherein the post-treatment includes performing different heat treatments on the first glass lens and the second glass lens collected separately. 4. Method.

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