JP2004300020A - Methods for manufacturing glass article and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing optical elements using preforms in a method for manufacturing higher quality glass articles at a higher speed. <P>SOLUTION: The method for manufacturing the glass articles comprises continuously separating glass masses from molten glass stream continuously outflowing from a nozzle and then shaping each separated glass mass at each glass shaping section . Each glass mass is separated from the molten glass stream by bringing a supporting member close to the tip end of the nozzle, receiving the tip end of the molten glass stream with the supporting member, and allowing the supporting member to descend at a speed higher than the outflow speed of the molten glass stream. The separated glass mass is shaped into the glass article after being transferred to the glass shaping section. The stop time of the glass shaping section, required for transferring the glass mass to the glass shaping section from the supporting member, or the time required for transferring the glass mass to the glass shaping section from the supporting member is made shorter than the time of one cycle required for preparing one glass mass from the molten glass stream by using the supporting member and transferring the glass mass to the glass shaping section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a glass article such as a preform for press molding of high quality from molten glass with high productivity, and a method for producing an optical element such as a lens by press-molding the preform. About.

  As a method of manufacturing a glass optical element such as an aspherical lens with high productivity, a method of heating and softening a glass article having a predetermined mass called a preform and press-molding with a press mold is widely used. According to this method, since the optical function surface such as the lens surface is precisely formed by press molding, it is not necessary to perform machining such as grinding and polishing on the optical function surface. Usually, the above method is called a precision press molding method or a mold optics molding method.

  In precision press molding, high internal quality and surface quality are required for preforms. If the internal quality is low, only an optical element with a low internal quality can be obtained. In addition, when a preform having a low surface quality is used, the surface quality of a molded article obtained is low. Since the optical function surface of the optical element manufactured by the precision press molding method is not machined, only an optical element with a low quality optical function surface can be obtained.

  By the way, as a method of manufacturing the preform, there are generally a method in which a glass material is machined into a preform having a predetermined mass, and a method in which molten glass having a predetermined mass is formed into a preform. The latter method is called hot preform molding and is an excellent method capable of mass-producing high-quality preforms. An example of such a hot preform molding method is disclosed in JP-A-8-81228 (Patent Document 1).

  The method described in Patent Document 1 circulates a plurality of dies arranged on an index table, and receives a predetermined amount of molten glass on the dies by moving the dies up and down at a casting position. . One of the movements of the mold is that when the mold moves immediately below the nozzle and the mold is lifted and stopped, the molten glass from the nozzle is placed on the mold surface and the required mass is reached. When the mold is rapidly lowered, the molten glass is separated from the nozzle. A glass of a predetermined mass is placed on the mold. The mold moves from directly below the nozzle, and the next mold enters immediately below the nozzle. By repeating this, the glass is continuously cut to form a glass lump.

Since this method does not cut at the shear, it is very suitable for producing a high-quality glass element without defects called a shear mark.
JP-A-8-81228

  However, since one mechanism performs the cutting operation and the circulating movement of the mold, when increasing the number of preforms to be produced, it is necessary to shorten the time for the next mold to enter immediately below the nozzle after cutting the glass. Must. Inevitably, the moving speed of the table is increased, and the lateral acceleration (lateral acceleration) applied to the molten glass during the movement is increased. Since the glass supplied to the mold is still in a high temperature state for a while after being supplied to the mold, a defect such as deformation occurs when a large lateral acceleration is applied. Also, a large lateral acceleration can cause a problem such as a defect occurring on the preform surface. In other words, as long as the cutting operation and the circulating movement of the mold are performed by one mechanism, there is naturally a limit in increasing the number of productions without causing the above problem.

  Further, since the height of the mold at the time of cutting affects the mass accuracy of the preform, it is necessary to finely adjust the heights of a plurality of molds in order to manufacture the preform with high mass accuracy. However, fine adjustment of the height of a plurality of dies imposes a heavy burden.

  The present invention overcomes the disadvantages of such a conventional method for manufacturing a glass article, a method for manufacturing a higher quality glass article at a higher speed, and an optical element using a preform manufactured by the method. The purpose is to provide a method of manufacturing.

  The present inventor has made intensive studies to solve the above-mentioned problems. As a result, the front end of the molten glass flow flowing out of the nozzle is separated into a glass lump using a member different from the glass forming section for forming glass, and is transferred to the glass forming section. It has been found that the above object can be achieved by forming a glass article while moving the glass, thereby completing the present invention.

The present invention for solving the above problems is as follows.
(1) A method for producing a glass article by continuously separating a glass lump from a molten glass flow continuously flowing out from a nozzle, and forming the separated glass lump in a glass forming section which moves intermittently or continuously. So,
A support member is brought close to the tip of the nozzle to receive the tip of the molten glass stream with the support member, and then the support member is lowered faster than the outflow speed of the molten glass stream to separate the glass block from the molten glass stream. And transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section. The time required to stop the glass forming section in order to transfer the glass block from the support member to the glass forming section is one cycle required for preparing one glass block from the molten glass flow using the supporting member and moving to the glass forming section. A method for producing a glass article, which is shorter than the time (hereinafter referred to as production method 1-1).
(2) A method for producing a glass article by continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming section which moves intermittently or continuously. So,
A support member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the support member, and the tip is supported to create a constriction between the nozzle side and the support side of the molten glass flow, and then the support member Lowering the glass block from the molten glass stream at the constriction and transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article. When transferring the glass block to the stopped glass forming section, the time for stopping the glass forming section to transfer the glass block from the supporting member to the glass forming section is determined by using the supporting member to remove one glass from the molten glass flow. A method for producing a glass article (hereinafter, referred to as a production method 1-2), which is shorter than a cycle time required for preparing a lump and moving to a glass forming section.
(3) A method in which a glass lump is continuously separated from a molten glass flow continuously flowing out from a nozzle, and the separated glass lump is formed in a glass forming section which moves intermittently or continuously to produce a glass article. So,
A support member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the support member, and the tip is supported to create a constriction between the nozzle side and the support side of the molten glass flow, and then the support member Removing the support to separate the glass mass from the molten glass stream at the constriction and transferring the separated glass mass to a stationary or moving glass forming section to form a glass article; and When transferring the glass block to the stopped glass forming section, the time to stop the glass forming section to transfer the glass block to the glass forming section, by preparing one glass block from the molten glass flow using the support member, A method for manufacturing a glass article (hereinafter referred to as manufacturing method 1-3), wherein the time is shorter than one cycle required to move to a glass forming part.
(4) The time for stopping the glass forming section to transfer the glass lump from the support member to the glass forming section, or the time for transferring the glass lump from the support member to the moving glass forming section, to the nozzle of the support member. (1) The method according to any one of (1) to (3), wherein the time from the start of approach to the completion of separation of the glass block is shortened.
(5) A method for producing a glass article by continuously separating a glass lump from a molten glass flow continuously flowing out from a nozzle, and forming the separated glass lump in a glass forming section which moves intermittently or continuously. So,
Receiving the tip of the molten glass flow with a supporting member, repeating the step of lowering the supporting member faster than the outflow speed of the molten glass flow and separating the glass lump at a constant cycle,
Transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section, A method for manufacturing a glass article, wherein the time for stopping the glass forming part for transferring the glass lump from the support member to the glass forming part is set to 70% or less of the period (hereinafter referred to as manufacturing method 2-1). .
(6) A method for producing a glass article by continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming section which moves intermittently or continuously. So,
The distal end of the molten glass flow is received by a support member, the distal end is supported to form a constriction between the nozzle side and the support side of the molten glass flow, and the supporting member is lowered to reduce the glass block from the molten glass flow at the constriction. Repeating the process of separating at regular intervals,
Transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section, A method for manufacturing a glass article, wherein the time for stopping the glass forming part for transferring the glass lump from the support member to the glass forming part is set to 70% or less of the period (hereinafter referred to as manufacturing method 2-2). .
(7) A method in which a glass lump is continuously separated from a molten glass flow continuously flowing out from a nozzle, and the separated glass lump is formed by a glass forming section that moves intermittently or continuously to produce a glass article. So,
The distal end of the molten glass flow is received by a support member, the distal end is supported to form a constriction between the nozzle side and the support side of the molten glass flow, and the support by the support member is removed to remove the glass from the molten glass flow at the constriction. Repeating the process of separating lumps at regular intervals,
Transferring the separated glass block to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to a stopped glass forming section, A method for manufacturing a glass article (hereinafter, referred to as a manufacturing method 2-3), wherein a time for stopping the glass forming section for transferring to the glass forming section is set to 70% or less of the period.
(8) The surface of the support member that receives the glass block is a plane, and the plane is rotated by 360 ° to transfer the glass block to the glass forming section. The method according to 1.
(9) The glass mass is dropped onto the glass member by tilting the surface of the support member that receives the glass mass, and the glass mass is moved to the glass forming part, and the falling direction of the glass mass and the moving direction of the glass molding part are matched. The manufacturing method according to any one of (1) to (8).
(10) The manufacturing method according to any one of (1) to (9), wherein two continuously prepared glass blocks are separated by receiving a molten glass flow on different surfaces of the support member. .
(11) The method according to any one of (1) to (10), wherein the glass block is turned upside down when the glass block is transferred from the support member to the glass forming section.
(12) The method according to any one of (1) to (11), wherein the support member receives the tip by ejecting gas from a surface of the support member that receives the tip of the molten glass flow.
(13) The method according to any one of (1) to (12), wherein the glass article is a preform for press molding made of optical glass.
(14) A method for producing an optical element, comprising heating and softening a glass article obtained by the production method according to (13), and then press-molding the glass article.

  According to the method for manufacturing a glass article of the present invention, the force (acceleration) applied to the glass being formed is reduced by independently performing the separation of the molten glass and the movement of the glass forming section, thereby increasing the quality of the glass article. It can be manufactured with productivity. In particular, even when the amount of outflow of the molten glass is increased, the glass forming portion can be moved with a margin. Also, compared to the conventional method, it is possible to greatly reduce the tact time (the time required for preparing one glass molded product).

In addition, according to the method for manufacturing a glass article of the present invention, the height of the plurality of glass lump molds does not need to be precisely adjusted in order to maintain the mass of the glass lump uniformly. it can. Therefore, it is possible to reduce the variation width of the mass of the glass article with a simple adjustment as compared with the related art.
Further, according to the method for producing a glass article of the present invention (an aspect in which a glass lump is reversed halfway), it is possible to increase the cooling efficiency and shorten the molding tact, and to obtain a glass article with less distortion.

Further, according to the method for producing a glass article of the present invention, a high-quality preform for press molding can be produced.
According to the method for manufacturing an optical element of the present invention, a high-quality press-molding preform is supplied under high productivity, so that a good optical element can be provided with high productivity, and the step in the pressing process can be improved. The stay is also improved.

  A first aspect of the method for producing a glass article of the present invention is a method of glass forming in which a glass lump is continuously separated from a molten glass flow continuously flowing from a nozzle, and the separated glass lump is intermittently or continuously moved. It is a method of manufacturing a glass article by molding in a part.

  Then, in the manufacturing method 1-1, the tip of the molten glass flow is received by the support member by bringing the support member close to the tip of the nozzle, and then the support member is lowered at a speed higher than the outflow speed of the molten glass flow to cause the melting. Separating a lump of glass from a glass stream, and transferring the separated lump of glass from a support member to a stopped or moving glass forming section to form a glass article, and the stopped glass When transferring a glass lump to the forming section, the time required to stop the glass forming section to transfer the glass lump from the support member to the glass forming section is determined by preparing one glass lump from the molten glass flow using the support member, and forming the glass. The time is shorter than one cycle required to move to the section.

  In the production method 1-2, a support member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the support member, and the tip is supported to form a constriction between the nozzle side and the support side of the molten glass flow. Then lowering the support member to separate the glass block from the molten glass stream at the constriction and transferring the separated glass block from the support member to a stationary or moving glass forming section. When molding the glass article, and when transferring the glass lump to the stopped glass forming section, the time to stop the glass forming section to transfer the glass lump from the support member to the glass forming section is melted using the support member. The method is characterized in that one glass lump is prepared from a glass stream, and is shorter than one cycle time required for moving to a glass forming part.

  In the manufacturing method 1-3, a supporting member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the supporting member, and the tip is supported to form a constriction between the nozzle side and the support side of the molten glass flow. Removing the support from the support member to separate the glass mass from the molten glass stream at the constriction, and transferring the separated glass mass to a stationary or moving glass forming section; Molding, and when transferring a glass block to a stopped glass forming section, the time to stop the glass forming section to transfer the glass block to the glass forming section is one time from the molten glass flow using the support member. The method is characterized in that the time required for preparing a glass block and moving to a glass forming section is shorter than one cycle.

  A second aspect of the method for producing a glass article of the present invention is a method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and moving the separated glass lump intermittently or continuously. This is a method for producing a glass article by molding in a molding section.

  Then, in the production method 2-1, a step of receiving the front end of the molten glass flow with a support member, lowering the support member faster than the outflow speed of the molten glass flow, and separating the glass lump, is repeated at a constant cycle. Transferring the separated glass lump from the support member to a stopped glass forming section or a moving glass forming section to form a glass article, and transferring the glass lump to the stopped glass forming section, A period in which the glass forming section is stopped in order to transfer the glass lump from the support member to the glass forming section is set to be equal to or less than 70% of the period.

  The production method 2-2 is such that the front end of the molten glass flow is received by a support member, the front end is supported to form a constriction between the nozzle side and the support body side of the molten glass flow, and the support member is lowered to form the constriction. Repeating a process of separating a glass lump from a molten glass flow at a constant cycle, transferring the separated glass lump from a support member to a stopped glass forming section or a moving glass forming section to form a glass article. And when transferring the glass block to the stopped glass forming section, the time for stopping the glass forming section to transfer the glass block from the support member to the glass forming section is set to 70% or less of the cycle. And

  In the manufacturing method 2-3, the front end of the molten glass flow is received by a supporting member, the front end is supported to form a constriction between the nozzle side and the support side of the molten glass flow, and the constriction is removed by removing the support by the supporting member. Repeating the step of separating the glass lump from the molten glass flow at a constant period in, transferring the separated glass lump to a stopped glass forming section or a moving glass forming section to form a glass article, and When the glass block is transferred to the stopped glass forming section, the time during which the glass forming section is stopped in order to transfer the glass block to the glass forming section is set to 70% or less of the period.

  FIG. 1 is a schematic side view showing an example of a glass article forming apparatus used in production methods 1-1, 1-2, 1-3 and production methods 2-1, 2-2, 2-3. Hereinafter, an example of the production methods 1-1, 1-2, and 1-3 will be described with reference to FIG. First, glass (molten glass) that has been melted, refined and homogenized in a melting furnace (not shown) is continuously discharged at a constant flow rate from the tip of a nozzle 1 made of platinum or a platinum alloy whose temperature has been adjusted. At this time, the preferable viscosity of the glass is 3 to 100 dPa · s, and the more preferable viscosity is 3 to 80 dPa · s.

  The support member 2 is arranged immediately below the nozzle, and a molten glass lump having a certain mass is separated from the flowing molten glass flow. Specifically, in the manufacturing method 1-1, the support member 2 is brought close to the tip of the nozzle 1 to receive the tip of the molten glass flow by the support member 2, and then the support member 2 descends faster than the outflow speed of the molten glass flow. This separates the glass block 6 from the molten glass stream. Further, in the manufacturing method 1-2, the support member 2 is brought close to the tip of the nozzle 1 and the tip of the molten glass flow is received and supported by the support member 2 to create a constriction between the nozzle side and the support member side of the molten glass flow. Then, the supporting member 2 is lowered to separate the glass block 6 from the molten glass stream. In any of the production methods 1-1 and 1-2, the separated glass block 6 is transferred from the support member 2 to the glass forming section 3 to form the glass article 7. Specifically, the separated glass block 6 is transferred to a glass forming section 3 provided in a concave shape on the upper part of a forming die arranged at equal intervals on the index table 5, and the glass forming section 3 is moved on the glass forming section 3. The glass article 7 is formed while moving. A heat-resistant metal such as stainless steel, carbon, or the like can be used as the material of the glass molded portion 3.

  In the manufacturing method 1-3, the support member 2 is brought close to the tip of the nozzle 1, the tip of the molten glass flow is received by the support member 2, and the tip is supported to create a constriction between the nozzle side and the support side of the molten glass flow. Then, the support by the support member 2 is removed to separate the glass block 6 from the molten glass stream at the constriction. In the manufacturing method 1-3, the separated glass block 6 is transferred to the stopped glass forming section 3 or the moving glass forming section 3 to form a glass article.

  In order to form a glass article having a high-quality surface such as a press-formed preform for making an optical element, it is desirable to minimize contact between the glass and the glass molded part during the molding. For this reason, pores are provided in the glass forming section, or the glass forming section is formed of a porous body, and gas is blown out from the holes to apply wind pressure to the glass to perform molding (referred to as floating molding). Is preferred.

  Although the glass lump 6 transferred to the glass forming section 3 is at a lower temperature than at the time of outflow, it is still at a high temperature and may be fused. Therefore, it is preferable to control the temperature of the glass forming part 3 to 300 ° C. or less to reliably prevent fusion. Further, in order to prevent fusion, a film such as a diamond-like carbon film may be provided on the surface of the glass molded portion. Further, a plurality of glass forming portions can be provided in one forming die. In this case, the movement of the glass forming unit is performed by, for example, rotation of the forming die, in addition to the movement of the index table by rotation.

  The index table 5 moves the glass forming unit 3 intermittently or continuously, carries the glass forming unit 3 to the glass lump receiving position, and unloads the glass forming unit that has received the glass lump from the receiving position. The glass forming section on the table is successively carried into the glass lump receiving position by the index rotation of the table, and is carried out after receiving the glass lump. The glass forming parts 3 are arranged at equal intervals on the table 5 so as to move to a predetermined position by a constant index rotation.

  The glass block is formed into a predetermined shape on a moving glass forming section and cooled to form a glass article 7 such as a preform for press forming. After cooling to a temperature at which the glass is not deformed (a temperature not higher than the glass transition temperature), the glass article 7 is sucked using the pick and place unit 4, taken out of the glass forming section 3, and transferred to the pallet 8. The pallet 8 is, for example, heated from above by a heater 9 so that the glass article is gradually cooled. Care should be taken to remove the glass article from the glass forming section and slowly cool it down so as not to damage the glass surface.For this reason, when removing the glass article from the mold using a vacuum pad, use a pad. It is appropriate that the height is adjusted so that the glass article is not pressed onto the glass molded portion, and the vacuum is performed at a position where the glass article does not come into contact with the glass article. It is preferable that the glass article is delivered to the pallet for slow cooling so that the glass article is not pressed against the pallet, and that the pallet is always kept clean so that there is no foreign matter harder than the glass.

  FIG. 2 shows an example of the operation of a descending cutter having a support member for separating a glass lump from a molten glass flow. Hereinafter, separation of the glass block by the support member will be described with reference to FIG. The support member 2 'has three "glass receiving surfaces". That is, the support member has a triangular prism shape whose bottom surface is an equilateral triangle, and moves vertically while the central axis of the triangular prism is kept horizontal, and the angle around the central axis is 120 ° or an integral multiple of 120 °. It has a function to rotate only. Cooling water may be flowed inside the support member to prevent glass fusion, so that molten glass does not fuse to the support member. The temperature of the support member is, for example, preferably in the range of 30 to 500 ° C, and more preferably in the range of 30 to 300 ° C. Further, the glass receiving surface is preferably mirror-finished, and its shape is preferably flat or a concave portion provided in a portion for receiving the molten glass.

Next, the operation will be described.
As shown in (a), the support member 2 ′ is raised vertically upward with the first glass receiving surface of the three glass receiving surfaces being horizontal with the first glass receiving surface facing upward, and a predetermined distance is set to the tip of the nozzle 1. And then stop.
(B) Next, the tip of the molten glass flow 6 flowing out of the nozzle 1 is placed on the glass receiving surface. In this state, constriction is created between the nozzle side and the support member side of the molten glass flow 6.
(C) Then, while keeping the glass receiving surface horizontal, the supporting member 2 'is lowered vertically downward at a speed higher than the outflow speed of the molten glass to separate the molten glass flow tip. Alternatively, the support member 2 'may be lowered while keeping the glass receiving surface horizontal, or the support may be removed to separate the tip from the molten glass stream at the neck. In this way, a molten glass lump 6 having a predetermined mass is obtained on the glass receiving surface. In addition, while the molten glass flow tip is received on the glass receiving surface, the support member may be slowly lowered at a speed lower than the speed at the time of separation so that the molten glass does not wet the outer periphery of the nozzle tip.
(D) Next, the support member 2 ′ is rotated 120 ° around the horizontal axis (around the center of the equilateral triangle having the vertical cross section) to drop the glass lump 6 from the glass receiving surface and transfer it to the glass forming section. With this drop, the upper and lower surfaces of the glass block are inverted. When the glass lump is put into the glass forming section 3, the glass is at or above the softening temperature and is in a viscosity range in which the glass can be formed sufficiently. It is preferable to separate the molten glass flow by controlling the distance between the nozzle tip and the glass receiving surface, the outflow speed of the glass, the timing of the descent of the support member 2 ', and the like, so that the mass of the glass lump 6 becomes constant.

  The support member 2 ′ rotated by 120 ° has the second glass receiving surface horizontal, but in this state, it is raised in the same manner as described above, is brought close to the nozzle tip to the above-described distance, and the glass lump separating step is repeated. . In this way, the glass block 6 having a predetermined mass is successively transferred to the glass forming section 3 while rotating the support member by 120 ° C., and the glass article can be formed.

  The shape of the support member is not limited to a regular triangular prism, and may be a regular polygonal prism such as a regular square prism, a regular pentagonal prism, or a flat plate. In the case of a regular n prism (n is an integer of 3 or more), the rotation angle of the support member can be an integral multiple of 360 ° / n, and in the case of a flat plate, it can be 180 ° or 360 °. In the case of a regular polygonal prism, the side surface can be used as a glass receiving surface, and in the case of a flat plate, the front surface and its back surface or one of them can be used as a glass receiving surface. It is preferable to use, for example, a heat-resistant metal material such as stainless steel for the support member.

In addition, the support member has a flat surface on which the glass block is received, and the flat surface is rotated by 360 ° so that the glass block can be transferred to the glass forming section.
Further, the supporting member is gradually moved in the horizontal direction when receiving the molten glass flow so that two continuously prepared glass blocks are separated by receiving the molten glass flow on different surfaces of the supporting member. You can also. For example, the support member can be moved gradually and periodically in the horizontal direction so that the same surface is subjected to the molten glass flow once every 2 to 10 times. Compared to the case where the molten glass flow is always received on the same surface, adhesion and deposition of volatile components of the glass on the surface of the support member that receives the molten glass flow can be avoided, which is advantageous in improving the glass quality.

  The support member separates the glass block and loads the glass block into the glass forming section by moving up and down and rotating. However, the support member used in the method of the present invention is not limited to those operating and moving as described above, and can separate a predetermined mass of glass lump from the molten glass flow without cutting it with a cutting blade, What is necessary is just a support member which can transfer it to a glass molding part.

  As another method of separating the glass lump and loading (moving) the glass lump, there is a method of moving the support member in a horizontal direction to separate the glass lump. In this method, as shown in FIG. 3, a plurality of support members 22 are radially attached at equal intervals around a rotating shaft 21 oriented in a vertical direction. By rotating the rotation shaft 21, the plurality of support members 22 move together in the horizontal direction. However, in order to separate the molten glass lump, the rotation shaft is rotated by a predetermined angle and one of the support members 22 is moved. The nozzle is stopped vertically below the nozzle 1. Next, the support member 22 is raised to approach the tip of the nozzle 1 to a predetermined distance, and receives the tip of the molten glass flow flowing down to the upper surface of the support member. When the front end of the molten glass flow is supported by the support member in this manner, a neck is generated between the nozzle side and the support member side of the molten glass flow. Then, by lowering the support member at a predetermined timing and rapidly separating the support member from the nozzle, the leading end of the molten glass flow 6 can be separated from the constriction.

This state will be further described with reference to FIG.
As shown in (a), the support member 22 has a glass receiving surface 24 and a glass outer peripheral holding surface 25 made of a porous member into which nitrogen gas has flowed out, and is disposed immediately below the nozzle 1. (B) The tip of the molten glass flow 6 flowing out of the nozzle 1 rides on the glass receiving surface. (C) The glass receiving surface 24 is vertically lowered at a speed higher than the outflow speed of the molten glass to separate the front end of the molten glass flow. A molten glass lump having a predetermined weight is obtained on the glass receiving surface 24 as described above. In addition, while the molten glass flow tip is received on the glass receiving surface, the support member may be slowly lowered at a speed lower than the speed at the time of separation so that the molten glass does not wet the outer periphery of the nozzle tip. (D) Next, the glass receiving surface 24 is quickly slid horizontally without moving the glass outer diameter holding surface 25. The glass block 6 is transferred without being inverted to the forming section 3 that has moved just below the nozzle. The glass receiving surface 22 'is moved directly below the nozzle 1 to receive the next glass block. By providing a plurality of glass receiving surfaces, the speed of the apparatus can be increased. In addition, it is preferable to remove volatile substances attached to the porous portion when no glass is received.

  The surface 24 for receiving the glass block may be made of a porous material. If the weight of the glass lump exceeds 1000 mg, defects such as folding deformation are likely to occur when the glass lump is inverted from the support member. These defects can be prevented by making the glass receiving surface a porous material, floating it with nitrogen gas or the like, and transferring the glass mass cut to a predetermined weight to a mold directly below without inverting.

  The outer diameter of the separated molten glass lump having a predetermined weight is regulated by a guide 23 having an outer diameter holding surface. It is desirable that the outer diameter of the molten glass lump 6 be equal to or smaller than the outer diameter of the glass lump to be formed. The reason is that if the outer diameter of the molten glass lump is larger than the outer diameter of the glass lump, the molten glass lump may protrude from the glass lump forming section 3 when the molten lump is put into the glass lump molding section. The guide moves vertically in a position vertically below the nozzle, but does not move horizontally. Then, when the support member on which the molten glass lump is placed is moved in the horizontal direction, the molten glass lump falls down vertically downward from the support member because the horizontal movement is hindered by the guide, and the molten glass lump falls in the glass lump forming section waiting below. Into a glass block.

  By repeating such a process, the molten glass lump is successively separated and transferred to a glass lump forming section to produce a glass lump. In order to ensure that the falling glass lump is received by the glass lump forming section, the rotation of the rotating shaft and the timing of the transfer of the glass lump forming section are synchronized, and the glass lump forming section rotates when the rotating shaft rotates. It may be located vertically below.

  In the above method, the support member was once raised from the stop position, and then received and supported by the molten glass flow tip, and was lowered to separate the glass. Separation can also be performed. In this case, the guide member is also fixed at a position below the nozzle without moving up and down. Then, the supporting member is transferred and stopped vertically below the nozzle to support the leading end of the molten glass flow. Next, by rapidly moving the support member in the horizontal direction at a predetermined timing, the support at the leading end of the molten glass flow is removed, the leading portion is separated from the neck of the molten glass flow, and falls into the glass lump forming section. .

  These methods have a feature that since the separated molten glass lump falls vertically downward and is transferred to the glass lump forming section, the glass is free from defects such as breakage. Since the breaking tends to occur easily when the glass lump becomes large, it is preferable to apply the above method particularly to the formation of a glass lump having a weight of 1000 mg or more.

  It is not necessary to use a plurality of support members in the above method, and it is sufficient to attach at least one support member around the rotation axis, but by using the plurality of support members, the surface of the support member that receives the glass even during operation of the apparatus is used. It can also be cleaned. By such cleaning, even if volatile matter from glass adheres, it can be removed.

  In the production methods 1-1, 1-2, and 1-3, the time for stopping the glass forming section to transfer the glass block from the supporting member to the glass forming section is determined by using the supporting member to remove one glass block from the molten glass flow. It is shorter than one cycle time required for preparation and transfer to the glass forming part. Alternatively, the time for transferring the glass lump from the support member to the glass forming section is shorter than the time required for one cycle of preparing one glass lump from the molten glass flow using the support member and moving the glass lump to the glass forming section. In this case, it is not necessary to stop the glass forming section. In the conventional method for preparing a glass lump from a molten glass stream, the time required to stop the glass forming section to receive the glass lump to the glass forming section, and the time required to prepare one glass lump from the molten glass stream are as follows: It was equal. On the other hand, in the manufacturing method 1 of the present invention, the stop time of the glass forming part is shorter than the time of one cycle required for preparing one glass lump and moving to the glass forming part. The time required for the movement can be lengthened, the lateral acceleration can be suppressed, and the quality of the glass molded product can be improved.

  More preferably, the time to stop the glass forming section to transfer the glass block from the support member to the glass forming section or the time to transfer the glass block from the supporting member to the glass forming section, Make it shorter than the time to complete the separation. For example, the stop time may be zero, that is, a lump of glass may be put into the moving glass forming part. Further, in that case, when the glass lump is introduced, the moving speed of the glass forming section can be made slower than in other cases.

  According to the production methods 1-1, 1-2, and 1-3, it is not necessary to directly receive the front end of the molten glass flow in the glass forming section, and therefore, the time that the glass forming section must be stopped to receive the glass lump ( (Stop time). Therefore, since the maximum moving speed of the glass forming portion can be reduced, the lateral acceleration applied to the glass during forming can be reduced, and a high quality glass molded product can be obtained while maintaining high productivity.

  In the production method 2-1, a step of receiving the front end of the molten glass flow by a support member and lowering the support member faster than the outflow speed of the molten glass flow to separate the glass lump is performed at a constant cycle (this cycle is defined as a cutting time). May be called). This step can be performed in the same manner as in the case of the above-described production method 1-1 described with reference to FIGS.

  In the manufacturing method 2-2, the front end of the molten glass flow is received by a support member, the front end is supported to form a constriction between the nozzle side and the support member side of the molten glass flow, and the support member is lowered to a predetermined position. The step of separating the heavy glass block is repeated at a constant cycle (this cycle may be referred to as a cutting time). This step can be performed in the same manner as in the case of the manufacturing method 1-2 described with reference to FIGS.

  In the manufacturing method 2-3, the front end of the molten glass flow is received by the support member, and the front end is supported to form a constriction between the nozzle side and the support member side of the molten glass flow, and the support of the support member is removed. The process of separating a glass block having a predetermined weight is repeated at a constant cycle (this cycle may be referred to as a cutting time). This step can be performed in the same manner as in the case of the above-described production method 1-3 described with reference to FIGS.

Further, in the manufacturing methods 2-1, 2-2, and 2-3, the time for stopping the glass forming section to transfer the glass block from the supporting member to the glass forming section or the time for transferring the glass block from the supporting member to the glass forming section. The time is set to 70% or less of the cutting time. Preferably, the stop time of the glass forming section or the time for transferring the glass block from the supporting member to the glass forming section is set to 50% or less of the cutting time.
The stop time may be zero, that is, a glass lump may be charged into the moving glass forming part. Further, in that case, when the glass lump is introduced, the moving speed of the glass forming section can be made slower than in other cases.

  According to the production methods 2-1, 2-2, and 2-3, it is not necessary to directly receive the front end of the molten glass flow in the glass forming section, and therefore, the time (stop time) required to stop to receive the glass lump ) Can be reduced and the maximum moving speed of the glass forming part can be reduced, so that the lateral acceleration applied to the glass being formed can be reduced, and a high quality glass molded product can be obtained while maintaining high productivity. it can.

Hereinafter, items common to the production methods 1-1, 1-2, and 1-3 and the production methods 2-1, 2-2, and 2-3 will be described.
It is preferable to limit the maximum lateral acceleration applied to the glass forming part so that the lateral inertial force applied to the glass on the glass forming part is 0.05 N or less.
The mass of the glass article to be molded is, for example, preferably 100 to 3000 mg, and more preferably 100 to 1000 mg. When the amount is less than 100 mg, a glass lump can be obtained with high mass accuracy by a dropping method, so it is needless to apply the method of the present invention, but the method of the present invention is applied to molding of a glass article of less than 100 mg. It does not hinder. In addition, when the mass of the glass article exceeds 1000 mg, defects such as folding deformation easily occur when the glass article is inverted and moved from the support member, particularly when the mass of the glass article exceeds 3000 mg, the tendency is increased. Become noticeable. If it exceeds 3000 mg, the glass becomes flat due to its own weight on the glass receiving surface, and it tends to be difficult to form the glass into a desired shape in the glass forming portion.

The production amount per unit time of the glass article is preferably 20 to 100 DPM (the number produced per minute from one nozzle), and more preferably 20 to 80 DPM.
In the above method, the preferred amount of pulling up the glass is 1 to 50 kg / day, and the preferred outflow speed of the molten glass is 1 to 15 mm / sec.

  The number of glass molding parts arranged on the index table can be, for example, 6 to 48. Further, the glass forming parts are preferably arranged at equal intervals on a circumference around the rotation axis of the table. The diameter of the circumference can be, for example, 300 to 500 mm.

  In the case where the glass lump is introduced into the moving glass molding section without stopping the glass molding section, the glass lump is preferably introduced along the moving direction of the glass molding section. More specifically, while tilting the surface of the support member that receives the glass lump to drop the glass lump and transfer the glass lump to the glass forming section, the falling direction of the glass lump and the moving direction of the glass forming section match. Is preferred. By doing so, a glass lump having a stable shape can be obtained.

  When transferring the glass lump from the support member to the glass forming section, the glass lump can be turned upside down. In this case, the glass block is turned upside down by rotating the support member, and the lower surface of the glass block preferentially cooled on the support member becomes the upper surface on the glass forming section. For this reason, in the glass forming part, the surface opposite to the surface that has been preferentially shredded first is preferentially cooled. As a result, since the glass block is cooled uniformly, there is an advantage that the temperature distribution on the upper and lower surfaces is reduced in the cooling process, the cooling rate is increased, and a glass article with less distortion can be formed.

  When the tip of the molten glass flow is directly received by the supporting member or the separated molten glass lump is directly supported on the supporting member, the heat of the glass is quickly taken away by the supporting member due to heat conduction, and the surface of the preform is heated. Wrinkles may occur. Such wrinkles are particularly disadvantageous in precision press molding preforms. Although it is conceivable that the temperature of the supporting member is increased to prevent rapid cooling of the glass, there is a possibility that the glass and the supporting member are fused. In order to prevent such wrinkles from occurring, gas may be blown from the glass receiving surface of the support member to reduce the time for which the molten glass and the support member come into direct contact, or to prevent both from coming into direct contact with each other. .

  Therefore, a gas ejection port is provided on the surface of the support member that receives the glass, and a gas is supplied from the gas flow path provided in the support member to the ejection port to eject the gas, wind pressure is applied to the glass, and the molten glass and the support member are applied. If the time for direct contact is reduced or the two are not directly contacted, even if wrinkles occur when gas is not ejected, the wrinkles can be eliminated. In addition, excessive gas ejection excessively cools the glass or blows gas to the nozzle, which is a factor that hinders stable outflow of the molten glass. Therefore, the gas ejection amount may be appropriately adjusted within a range in which the above object can be achieved and the above problem does not occur.

  The gas ejection method from the support member can be applied to any of the production methods 1-1, 1-2, 1-3, 2-1 and 2-2, and 2-3. The present invention can also be applied to a method of moving to remove the support of the molten glass flow tip and separating the molten glass lump.

  In addition, even in the separation of the molten glass mass using the guide described above, a gas outlet is provided on the outer diameter holding surface to eject gas to reduce direct contact between the outer diameter holding surface of the guide and the glass. Or can be prevented.

  A large number of fine holes may be provided on the surface of the support member that receives the glass and the outer diameter holding surface of the guide, and gas may be ejected from those holes, or the surface may be formed of a porous material, The gas may be ejected through the body.

  According to the method of the present invention, in a method of forming a glass having a predetermined mass in a glass forming section that circulates and moves on an index table or the like, rotation of the table (that is, movement of the glass forming section and the glass block) and melting of the glass block are performed. By separating the separation operation from the glass flow, for example, even if the outflow speed of the molten glass is increased, sudden acceleration and sudden deceleration of the table can be avoided. Therefore, the lateral acceleration applied to the glass lump is reduced, and the glass lump can be formed into a good shape, particularly a shape suitable for a press-forming preform. The method of the present invention is particularly suitable for floating molding in which molding is performed while reducing contact between a glass lump and a glass molding portion.

  Further, even when the outflow speed of the molten glass is increased, the movement of the glass forming portion can be performed with a margin. Further, since the stop time of the glass forming section can be reduced, the tact time can be significantly reduced.

  In the method of the present invention, the glass article can be a press-forming preform made of optical glass. The shape of the preform for press molding will be described. The preform shape is determined according to the shape of the press-formed product. When an axially symmetric optical element such as a lens is press-formed, it is preferable that the preform also has an axially symmetric shape. For example, there are a spherical shape and a repellent shape (flat shape). In addition, during press molding, gas may be trapped between the press mold and the preform, and the gas may hinder glass forming, thereby causing a defect called a gas trap defect. Therefore, in consideration of this point, it is preferable that the curvature of the preform surface be tighter (increased) than the curvature of the press molding surface.

  The present invention includes a method for producing an optical element, which comprises heating and softening a glass article, preferably a preform, obtained by the above-mentioned production method of the present invention, followed by press molding. More specifically, an optical element can be manufactured by heating again a press-forming preform made of optical glass formed by the above-described method and then gradually cooled, and press-forming with a press-forming die. The preform before reheating can be washed and dried as necessary, and may form a film having a releasing action and a lubricating action so that the glass is easily spread on the surface of the press mold. .

  When machining is not performed on an optical function surface such as a lens surface, it is preferable to apply a precision press molding method to the press molding. In the precision press molding method, use a mold material made of SiC, cemented carbide, heat resistant metal, etc., and use a press mold with a release film such as a carbon film or a noble metal film on the molding surface as necessary. Press molding can be performed in an atmosphere such as nitrogen, a mixed gas of nitrogen and hydrogen, or an inert gas. After the optical element formed by press molding is gradually cooled, an optical thin film such as an anti-reflection film may be provided as needed.

  The optical element that can be formed by the above method is not particularly limited, and examples thereof include various lenses such as an aspheric lens, a spherical lens, a cylindrical lens, a macro lens, and a lens array, a prism, a polygon mirror, and a diffraction grating.

Hereinafter, the present invention will be described in more detail with reference to Examples.
(Example 1)
Finally, the glass material prepared to obtain the desired optical properties such as refractive index, dispersion, and transmittance is heated and melted, defoamed, clarified, and stirred and homogenized. It flows down continuously from the alloy nozzle at a constant outflow speed. At this time, the lifting amount of the glass was 10 kg / day, and the outflow speed was 2.5 mm / sec.
The flowing molten glass stream is formed into a press-forming preform by the apparatus shown in FIGS.

  The support member used in this example is a stainless steel triangular prism having a bottom surface of a regular triangle having a side of 20 mm. In order to prevent fusion with the molten glass, a hole of φ8 mm is made in the center of the support member, and water is cooled by flowing cooling water.

  First, the support member of the descending cutting machine is raised, moved to 3 mm below the mirror-finished glass receiving surface and the tip of the nozzle, and then stopped. In this state, the glass receiving surface is maintained in a horizontal state (a state in which the glass receiving surface faces vertically upward). Next, the front end of the molten glass flowing down from the nozzle is placed on the glass receiving surface. Since the size of the molten glass on the glass receiving surface increases with time, the supporting member is vertically lowered at a low speed of 1 mm / sec to prevent the molten glass from getting wet on the outer periphery of the nozzle tip.

  When the molten glass is accumulated on the glass receiving surface as much as a molten glass mass having a desired mass can be obtained, the supporting member is rapidly dropped at a speed of 10 mm / sec, which is faster than the outflow speed of the molten glass, and the molten glass flow generated by the surface tension of the glass is reduced. The tip side is separated from the constricted portion to obtain a molten glass lump having a predetermined mass on the glass receiving surface. Next, the support member is rotated by 120 ° around the central axis of the triangular prism, and the glass lump is thrown into a glass receiving portion provided on the upper surface of the glass lump mold waiting below the support member. The thrown glass lump is placed on the glass forming section with the upper and lower surfaces inverted, and is float-formed.

  The descending cutting machine repeats the operation of separating the molten glass lump and putting the glass lump into the glass forming section. The glass lump mold reliably receives the separated glass lump in synchronization with the operation of the descending cutter. The glass block entering the glass forming section is formed into a preform shape while moving together with the glass forming die, and is cooled and solidified with time. The solidified preform is sucked out of the glass forming part, transferred to a pallet and gradually cooled. In this way, preforms of a predetermined mass are successively manufactured from the molten glass that flows continuously.

  The number of glass lump forming dies arranged at equal intervals along the circumference of the index table is twelve, and one glass forming portion is provided at the top of each of the dies. The diameter of the circumference was 400 mm.

The time at which the glass forming part stops at the position where the glass block is received is 1.0 second, the time from the start of the rising of the support member to the completion of separation of the glass block is 1.5 seconds, and the cutting time is set to 3.0 seconds. A preform for press molding of 3 mg was produced. The preform molding speed at this time is 20 DPM. The lateral force exerted by the glass block on the glass forming part is at most 5 × 10 ⁻⁵ N. The control of the apparatus including the descending cutter and the index table is performed using a sequencer.

The preform for press molding formed in this manner had a rotationally symmetric shape, and no defects such as cracks and striae were observed. Also, the mass accuracy sufficiently satisfied the requirements in precision press molding.
The surface of the support member that receives the front end of the molten glass flow may be formed of a porous body, and gas may be ejected from the surface to reduce the contact between the glass and the support.

  In order to keep the mass accuracy of the preform within the above range, adjustment is made so that each of the three glass receiving surfaces receives the molten glass flow at the same height (within 25 μm). Fine adjustment of the vertical position of the glass lump mold is unnecessary.

  Next, using a plurality of supporting members having a surface receiving the molten glass flow tip made of a porous body, disposing them at equal intervals around the rotation axis as described above, and raising the supporting members vertically below the nozzle. After that, the molten glass flow tip was supported, and then the supporting member was rapidly lowered to separate the molten glass lump. In this method, a guide provided with a large number of gas ejection ports made of a porous body on the outer peripheral holding surface is arranged around the glass on the support member to eject gas to regulate the outer diameter of the molten glass lump, The glass is not pulled when it is moved rapidly in the horizontal direction. Other conditions were the same as those described above.

The preform for press molding formed in this manner had a rotationally symmetric shape, and no defects such as cracks and striae were observed. Also, the mass accuracy sufficiently satisfied the requirements in precision press molding.
Each of the preforms formed as described above was suitable as a preform for precision press molding.

(Comparative example)
The dropping cutting device was removed from the above device, and molding was performed at the same mass and at the same production speed as the above preform by a conventional device provided with a drop cutting function in the glass lump forming mold, and the formed preform was deformed. However, it did not become a rotationally symmetric shape. Also, some preforms were found to have fragrance. The time during which the glass lump mold stops to receive the molten glass lump is 2.5 seconds, and the maximum lateral force applied to the glass lump during movement is 7 × 10 ⁻⁴ N. As described above, it is considered that the defective product was generated because a large force acts on the glass lump during the movement and the cooling speed of the glass lump differs greatly between the upper and lower surfaces.

  In this comparative example, fine adjustments were made to all the twelve glass lump molds so that the height when receiving the molten glass was within 50 μm, but the mass tolerance was ± 10 mg.

(Example 2)
After cleaning and drying the preform molded in Example 1, precision press molding was performed to produce an aspheric lens. In the above press molding, a press molding die having a carbon film formed on the surface of a SiC mold material was used, and the atmosphere was a nitrogen atmosphere. Press molding was performed by heating the preform to 635 ° C. and pressing it at a pressure of 100 kgf / cm ² for 60 seconds. After press molding, the aspherical lens was taken out of the mold and gradually cooled. The obtained lens was in a good condition both inside and on the surface. The lens may be subjected to a centering process as necessary, and an antireflection film may be formed on the surface.

  The present embodiment relates to a method of manufacturing an aspherical lens, but can be applied to the manufacture of other optical elements such as a prism and a diffraction grating.

  INDUSTRIAL APPLICABILITY The present invention is useful for producing glass articles such as preforms for press molding of high quality from molten glass, and for producing optical elements such as lenses by press-molding the preforms.

It is the schematic from the side which shows an example of the glass article shaping | molding apparatus used by the manufacturing method of this invention. It is the schematic from the side direction for demonstrating operation | movement of the support member in the glass article shaping | molding apparatus used by the manufacturing method of this invention. It is the schematic from the upper direction for demonstrating operation | movement of the support member in the glass article shaping | molding apparatus used by the manufacturing method of this invention. It is the schematic from the side direction for demonstrating operation | movement of the support member in the glass article shaping | molding apparatus used by the manufacturing method of this invention.

Claims (14)

A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
A support member is brought close to the tip of the nozzle to receive the tip of the molten glass stream with the support member, and then the support member is lowered faster than the outflow speed of the molten glass stream to separate the glass block from the molten glass stream. And transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section. The time required to stop the glass forming section in order to transfer the glass block from the support member to the glass forming section is one cycle required for preparing one glass block from the molten glass flow using the supporting member and moving to the glass forming section. A method for manufacturing a glass article, wherein the time is shorter than the time. A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
A support member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the support member, and the tip is supported to create a constriction between the nozzle side and the support side of the molten glass flow, and then the support member Lowering the glass block from the molten glass stream at the constriction and transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article. And when transferring the glass block to a stopped glass forming section, the time to stop the glass forming section to transfer the glass block from the supporting member to the glass forming section is determined by using the supporting member to remove one glass from the molten glass flow. A method for producing a glass article, comprising preparing a lump and making it shorter than one cycle time required for moving to a glass forming part. A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
A support member is brought close to the tip of the nozzle, the tip of the molten glass flow is received by the support member, and the tip is supported to create a constriction between the nozzle side and the support side of the molten glass flow, and then the support member Removing the support to separate the glass mass from the molten glass stream at the constriction and transferring the separated glass mass to a stationary or moving glass forming section to form a glass article; and When transferring the glass block to the stopped glass forming section, the time to stop the glass forming section to transfer the glass block to the glass forming section, by preparing one glass block from the molten glass flow using the support member, A method for manufacturing a glass article, wherein the time is shorter than one cycle required for moving to a glass forming part.   The time to stop the glass forming section to transfer the glass block from the support member to the glass forming section, or the time to transfer the glass block to the moving glass forming section from the supporting member, start approaching the support member to the nozzle. The production method according to any one of claims 1 to 3, wherein the time is shorter than the time until the completion of the separation of the glass lump. A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
Receiving the tip of the molten glass flow with a supporting member, repeating the step of lowering the supporting member faster than the outflow speed of the molten glass flow and separating the glass lump at a constant cycle,
Transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section, A method for producing a glass article, wherein the time for stopping the glass forming section in order to transfer the glass lump from the support member to the glass forming section is set to 70% or less of the period. A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
The distal end of the molten glass flow is received by a support member, the distal end is supported to form a constriction between the nozzle side and the support side of the molten glass flow, and the supporting member is lowered to reduce the glass block from the molten glass flow at the constriction. Repeating the process of separating at regular intervals,
Transferring the separated glass block from the support member to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to the stopped glass forming section, A method for producing a glass article, wherein the time for stopping the glass forming section in order to transfer the glass lump from the support member to the glass forming section is set to 70% or less of the period. A method for continuously separating a glass lump from a molten glass flow continuously flowing from a nozzle, and forming the separated glass lump in a glass forming unit that moves intermittently or continuously, to produce a glass article,
The distal end of the molten glass flow is received by a support member, the distal end is supported to form a constriction between the nozzle side and the support side of the molten glass flow, and the support by the support member is removed to remove the glass from the molten glass flow at the constriction. Repeating the process of separating lumps at regular intervals,
Transferring the separated glass block to a stopped glass forming section or a moving glass forming section to form a glass article; and transferring the glass block to a stopped glass forming section, A method for manufacturing a glass article, wherein the time for stopping the glass forming part for transferring to the glass forming part is set to 70% or less of the period.   The surface of the support member that receives the glass lump is a plane, and the plane is rotated by 360 ° to transfer the glass lump to a glass forming unit, according to any one of claims 1 to 7, wherein Production method.   The method for tilting a surface of a support member for receiving a glass lump to drop the glass lump and transfer the glass lump to a glass forming section, and wherein a falling direction of the glass lump coincides with a moving direction of the glass forming section. Item 9. The method according to any one of Items 1 to 8.   The method according to any one of claims 1 to 9, wherein two continuously prepared glass blocks are separated by receiving a molten glass flow on different surfaces of the support member.   The method according to any one of claims 1 to 10, wherein the glass block is turned upside down when the glass block is transferred from the support member to the glass forming section.   The method according to any one of claims 1 to 11, wherein a gas is ejected from a surface of the supporting member that receives the front end of the molten glass flow to receive the front end.   The method according to any one of claims 1 to 12, wherein the glass article is a preform for press molding made of optical glass.   A method for producing an optical element, comprising heating and softening a glass article obtained by the production method according to claim 13, and then press-molding the glass article.