Glass production method, glass production apparatus, glass, optical element, optical system, and levitation-melted glass

Abstract

Provided is a glass production method for producing a glass from a glass raw material, the method including: heating the glass raw material into a molten state; supporting the glass raw material in the molten state in a non-contact manner; and irradiating the glass raw material with an electromagnetic wave. The irradiating the glass raw material with an electromagnetic wave includes: irradiating the glass raw material in the molten state and being supported in the non-contact manner with a first electromagnetic wave that is absorbed by the glass raw material with a first absorption coefficient; irradiating the glass raw material in the molten state and being supported in the non-contact manner with a second electromagnetic wave that is absorbed by the glass raw material at a second absorption coefficient that is smaller than the first absorption coefficient; and stopping the irradiation of the glass raw material with the second electromagnetic wave after stopping the irradiation of the glass raw material with the first electromagnetic wave.

Description

Glass manufacturing method, glass manufacturing apparatus, glass, optical element, optical system, and floating molten glass

[0001] The present invention relates to a glass manufacturing method, a glass manufacturing apparatus, glass, an optical element, an optical system, and a floating molten glass. This invention claims priority to Japanese Patent Application No. 2024-130901 filed on August 7, 2024, and the contents of that application are incorporated by reference into this application in designated states where incorporation by reference of documents is permitted.

[0002] For example, Patent Document 1 discloses a method for manufacturing optical glass using a laser levitation furnace.

[0003] Japanese Patent Application Laid-Open No. 2021-046354

[0004] An aspect of the present invention is, for example, a glass manufacturing method for manufacturing glass from glass frits, comprising: heating the glass frits to make them into a molten state; supporting the glass frits in a molten state in a non-contact manner; and irradiating the glass frits with electromagnetic waves, wherein the irradiating the electromagnetic waves to the glass frits comprises: irradiating the glass frits in a molten state supported in a non-contact manner with a first electromagnetic wave, which is absorbed by the glass frits with a first absorption coefficient; irradiating the glass frits in a molten state supported in a non-contact manner with a second electromagnetic wave, which is absorbed by the glass frits with a second absorption coefficient smaller than the first absorption coefficient; and stopping the irradiation of the first electromagnetic wave to the glass frits, and then stopping the irradiation of the second electromagnetic wave to the glass frits.

[0005] Another aspect of the present invention is, for example, a glass manufacturing method for manufacturing glass from glass frits, comprising: heating the glass frits to make them into a molten state; supporting the glass frits in a molten state in a non-contact manner; and irradiating the glass frits with electromagnetic waves, wherein the irradiating the electromagnetic waves to the glass frits comprises: irradiating the glass frits in a molten state supported in a non-contact manner with a first electromagnetic wave, which is absorbed by the glass frits with a first absorption coefficient; irradiating the glass frits in a molten state supported in a non-contact manner with a second electromagnetic wave, which is absorbed by the glass frits with a second absorption coefficient smaller than the first absorption coefficient; and reducing the irradiation amount of the first electromagnetic wave to the glass frits, and then stopping the irradiation of the second electromagnetic wave to the glass frits.

[0006] Another aspect of the present invention is a method for producing glass from glass frits, the method comprising: heating the glass frits to make them into a molten state; supporting the glass frits in the molten state in a non-contact manner; and irradiating the glass frits with electromagnetic waves, wherein the irradiating of the electromagnetic waves comprises irradiating the glass frits with first electromagnetic waves having a wavelength of 100 nm or more and less than 400 nm or a wavelength of 5000 nm or more and less than 10 cm, and reducing the volume of the glass frit to V mm ３ The glass raw material in the molten state is supported in a non-contact manner and irradiated with the first electromagnetic wave for at least 0.02 × V seconds.

[0007] Another aspect of the present invention is a method for producing glass from glass frits, comprising: heating the glass frits to a molten state; supporting the glass frits in a molten state in a non-contact manner; and irradiating the glass frits with electromagnetic waves, wherein the irradiating of the electromagnetic waves comprises irradiating the glass frits with second electromagnetic waves having a wavelength of 400 nm or more and less than 5000 nm, and the steps of supporting the glass frits in a molten state in a non-contact manner and irradiating the second electromagnetic waves are carried out for at least 10 seconds continuously.

[0008] Another aspect of the present invention is a glass manufacturing apparatus for manufacturing glass from glass raw materials, the apparatus comprising: a heating device for heating the glass raw materials; a support member for supporting the glass raw materials in a molten state in a non-contact manner; and a cooling device for lowering the temperature of the support member.

[0009] Another aspect of the present invention is a floating molten glass, wherein the difference between the maximum refractive index and the minimum refractive index in the floating molten glass is 100×10 －６ The following is the result.

[0010] Another aspect of the present invention is a glass comprising, in mole percent, B ２ O ３ , SiO ２ , P ２ O ５ and As ２ O ３ The total content of (B ２ O ３ +SiO ２ +P ２ O ５ +As ２ O ３ ): 25% or less, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ The total content of (Li ２ O+K ２ O + Na ２ O+P ２ O ５ +B ２ O ３ +WO ３ +As ２ O ３ ): 10% or less, La ２ O ３ , BaO, CaO, MgO, Y ２ O ３ , Gd ２ O ３ , Al ２ O ３ , TiO ２ , Nb ２ O ５ , ZrO２ and Ta ２ O ５ Total content (La ２ O ３ +BaO+CaO+MgO+Y ２ O ３ +Gd ２ O ３ +Al ２ O ３ + TiO ２ +Nb ２ O ５ + ZrO ２ +Ta ２ O ５ ): 70% or more, and a first index, which is the difference between the maximum and minimum values ​​of the optical path length corresponding to a length of 1 mm in the glass, is 100 nm or less.

[0011] Another aspect of the present invention is a glass comprising, in mole percent, B ２ O ３ , SiO ２ , P ２ O ５ and As ２ O ３ The total content of (B ２ O ３ +SiO ２ +P ２ O ５ +As ２ O ３ ): 25% or less, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ The total content of (Li ２ O+K ２ O + Na ２ O+P ２ O ５ +B ２ O ３ +WO ３ +As ２ O ３ ): 10% or less, La ２ O ３ , BaO, CaO, MgO, Y ２ O３ , Gd ２ O ３ , Al ２ O ３ , TiO ２ , Nb ２ O ５ , ZrO ２ and Ta ２ O ５ Total content (La ２ O ３ +BaO+CaO+MgO+Y ２ O ３ +Gd ２ O ３ +Al ２ O ３ + TiO ２ +Nb ２ O ５ + ZrO ２ +Ta ２ O ５ ): 70% or more, and the difference between the maximum refractive index and the minimum refractive index in the glass is 100 × 10 －６ The following is the result.

[0012] Another aspect of the present invention is a glass having a partial dispersion ratio (P ｇ，Ｆ ) and Abbe number (ν ｄ ) is P ｇ，Ｆ ≦−0.0042×ν ｄ +0.7193 and the wavelength (λ ８０ ) and Abbe number (ν ｄ ) is λ ８０ ≦−10.253×ν ｄ +672.5, and the glass transition temperature T ｇ ≥ 780°C, the difference ΔT between the crystallization onset temperature and the glass transition temperature ≤ 230°C, and the difference between the maximum and minimum refractive indices in the glass is 100 × 10 －６ The following is the result.

[0013] Another aspect of the present invention is an optical glass using the above-mentioned glass.

[0014] Another aspect of the present invention is an optical element comprising the glass described above.

[0015] Another aspect of the present invention is an optical system including the optical element described above.

[0016] 7A is a schematic diagram of a manufacturing apparatus including a support member according to the first embodiment. FIG. 7B is a schematic diagram of a manufacturing apparatus including a support member according to the third embodiment. FIG. 7C is a schematic diagram of a measurement target region R1 of the first measurement method. FIG. 7D is a schematic diagram of a glass before processing by the second measurement method. FIG. 7E is a schematic diagram of a glass after processing by the second measurement method. FIG. 7F is a schematic diagram of a measurement target region R2 of the second measurement method. FIG. 7C is a schematic diagram of a measurement target region R2 of the second measurement method. FIG. 7D is a schematic diagram of a glass before processing by the second measurement method. FIG. 7E is a schematic diagram of a glass after processing by the second measurement method. FIG. 7F is a schematic diagram of a measurement target region R2 of the second measurement method. FIG. 7C is a schematic diagram of a measurement target region R2 of the second measurement method. FIG. 7D is a schematic diagram of a glass before processing by the second measurement method. FIG. 7E is a schematic diagram of a glass after processing by the second measurement method. FIG. 7F is a schematic diagram of a measurement target region R2 of the second measurement method. FIG. 8(A) shows the irradiation position when a single laser beam is irradiated, FIG. 8(B) shows the flow velocity distribution when a single laser beam is irradiated, and FIG. 8(C) shows the temperature distribution when a single laser beam is irradiated. V1 in FIG. 8(A) indicates the laser irradiation position in the simulation. This is a diagram (part 2) showing the results of a fluid simulation. FIG. 9(A) shows the irradiation position when a three-point laser beam is irradiated, FIG. 9(B) shows the flow velocity distribution when a three-point laser beam is irradiated, and FIG. 9(C) shows the temperature distribution when a three-point laser beam is irradiated. This is a diagram (part 3) showing the results of a fluid simulation. FIG. 10(A) shows the irradiation position when a four-point laser beam is irradiated, FIG. 10(B) shows the flow velocity distribution when a four-point laser beam is irradiated, and FIG. 10(C) shows the temperature distribution when a four-point laser beam is irradiated. These are Schlieren images taken from above of the glass of the example or comparative example. 11A is a schlieren image of the glass of Example 5, and FIG. 11B is a schlieren image of the glass of Comparative Example 1. FIG. 11B is a perspective view of an example in which the optical device according to each embodiment is used as an imaging device. FIG. 11C is a front view of another example in which the optical device according to each embodiment is used as an imaging device. FIG. 11D is a rear view of another example in which the optical device according to each embodiment is used as an imaging device.1 is a block diagram showing an example of a case where the optical device according to each embodiment is used as a multiphoton microscope.

[0017] An embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described below. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content.

[0018] In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0019] Furthermore, terms with "abbreviation" attached indicate the meaning of the term excluding "abbreviation" within the scope of common general technical knowledge of a person skilled in the art, and also include the meaning itself excluding "abbreviation." The same is true vice versa. For example, the term "circle" does not have "abbreviation" attached, but naturally includes the meaning of "approximately circle" as long as it does not contradict the gist of the invention.

[0020] <First embodiment: irradiation of first electromagnetic wave L1> <Outline of manufacturing apparatus 10> Fig. 1 is a schematic diagram of a manufacturing apparatus 10 including a support member 12 according to a first embodiment. As shown in Fig. 1, the manufacturing apparatus 10 is a glass manufacturing apparatus. The manufacturing apparatus 10 manufactures glass through a process of levitating glass frit U by gas, and at some point in time, heating and melting the glass frit U to lower the temperature of the glass frit U. Note that levitating the glass frit U by a levitation unit 21 described below is also referred to as supporting the glass frit U in a non-contact manner.

[0021] The glass raw material U is a press-molded body, a sintered body of the press-molded body, or an aggregate of crystals. Before the glass raw material U is placed on the support member 12 described below, the raw materials constituting the glass raw material U are mixed.

[0022] The manufacturing apparatus 10 includes a stage 11, a support member 12 for supporting the glass frit U in a non-contact manner, a light source 13 for irradiating the levitated glass frit U with a first electromagnetic wave L1, mirrors 14 and 15 for guiding the first electromagnetic wave L1 to the glass frit U, a radiation thermometer 16 for measuring the temperature of the levitated glass frit U, a computer 17 having a control unit (not shown) for controlling the output of the light source 13 based on temperature information from the radiation thermometer 16, a CCD camera 18, a monitor 19, and a gas flow regulator 20 for controlling the gas supplied to the glass frit U specified by the support member 12.

[0023] The support member 12 has supply holes on its upper surface for ejecting gas, and the glass frit U is supported in a non-contact manner by the gas ejected from the supply holes. For example, the manufacturing apparatus 10 heats the glass frit U floating above the support member 12 arranged on the stage 11 in a non-contact manner by irradiating it with a first electromagnetic wave L1. In other words, the light source 13 that irradiates the first electromagnetic wave L1 and the mirrors 14 and 15 that direct the first electromagnetic wave L1 to the glass frit U function as a first heating device that heats the glass frit U. As a result, the glass frit U melts and becomes a molten liquid having a substantially spherical or substantially ellipsoidal shape due to its own surface tension, and floats in that state.

[0024] The temperature of the glass frit U heated by the irradiation of the first electromagnetic wave L1 is monitored by a radiation thermometer 16. Based on the temperature information of the glass frit U monitored by the radiation thermometer 16, the output of the light source 13 is controlled by a computer 17. In addition, the state of the glass frit U is photographed by a CCD camera 18, and the photographed image is output to a monitor 19.

[0025] The light source 13 emits a first electromagnetic wave L1. The wavelength of the first electromagnetic wave L1 is 100 nm or more and less than 400 nm, or 5000 nm or more and less than 10 cm. As long as the wavelength of the emitted electromagnetic wave is within this range, the configuration of the light source 13 is not particularly limited. For example, a carbon dioxide laser, a semiconductor laser, a fiber laser, a YAG laser, a microwave generator, or the like can be used as the light source 13. For example, the stably levitated glass raw material U is heated non-contact, and then the first electromagnetic wave L1 is blocked. As a result, the melt (glass raw material U) is cooled and vitrified, thereby obtaining glass. The glass obtained in this embodiment is, for example, optical glass. Note that the glass obtained in this manner is called floating melt glass. Thereafter, the glass is processed into a desired shape and polished as necessary to form a desired optical element.

[0026] The flow rate of the gas fed into the support member 12 is controlled by a gas flow regulator 20. The type of gas is not particularly limited, and any known gas can be used as appropriate. Specific examples include oxygen, carbon dioxide, nitrogen, argon, and air. The shape of the nozzle (not shown) connected to the support member 12 is not particularly limited, and any known method can be used as appropriate.

[0027] The support member 12 may levitate the glass frit U using static electricity. In this case, the manufacturing apparatus 10 does not have the gas flow regulator 20, but instead has an electrostatic device (not shown) that charges the glass frit U. The support member 12 can levitate the glass frit U, which is placed between one or more pairs of electrodes constituting the electrostatic device, using static electricity. In addition, the method by which the support member 12 levitates the glass frit U is not limited to the above example, and may be, for example, an electromagnetic method, an ultrasonic method, a magnetic method, or the like.

[0028] Conventionally, in glass production using the float melting method, glass frits are melted by laser irradiation and the molten frits are supported in a non-contact manner. In this case, if the glass frits are supported in a non-contact manner for a long time, the glass frits in a molten state may come into contact with the support member 12, which may cause devitrification of the glass frits. Therefore, the period during which the glass frits are supported in a non-contact manner tends to be limited to a short period. In this case, the composition may not be uniform in different parts of a single glass, which may result in non-uniform refractive index in different parts of the glass (the occurrence of striae).

[0029] On the other hand, the glass manufacturing apparatus 10 of the present embodiment has a volume of glass raw material U of V mm ３ When the temperature is set to 0.02 × V seconds or more, the frit U in a molten state is supported in a non-contact state for 0.02 × V seconds or more. Furthermore, the glass manufacturing apparatus 10 of this embodiment continuously irradiates the frit U supported in a non-contact state with a first electromagnetic wave L1 having a wavelength of 100 nm or more but less than 400 nm, or 5000 nm or more but less than 10 cm, for 0.02 × V seconds or more. Because electromagnetic waves of such wavelengths are easily absorbed by glass (i.e., absorbed by glass with a larger absorption coefficient), they are absorbed in large amounts, particularly at the surface of the frit U, causing the temperature of the surface of the frit U irradiated with the electromagnetic wave to rise. As a result, a temperature gradient occurs between the surface and the interior of the frit U in a molten state. This temperature gradient causes convection within the frit U. By maintaining the frit U in a non-contact state for 0.02 × V seconds or more and irradiating the frit U with the first electromagnetic wave L1, the interior of the glass is sufficiently stirred by convection, making the composition of different parts of the glass more uniform and suppressing the occurrence of striae.

[0030] In this embodiment, the wavelength of the first electromagnetic wave L1 is 100 nm or more and less than 400 nm, or 5000 nm or more and less than 10 cm. It is more preferably 5000 nm or more and less than 20000 nm, more preferably 8000 nm or more and less than 12000 nm, and even more preferably 9000 nm or more and less than 11000 nm. By using such a wavelength range, the glass raw material can be heated more efficiently. A carbon dioxide laser can be used as an example of the light source 13.

[0031] The lower limit of the first absorption coefficient, which is the absorption coefficient of the first electromagnetic wave L1 for the glass raw material U of this embodiment, is preferably 1 cm －１ and more preferably 10 cm －１ and more preferably 100 cm －１ is.

[0032] In this embodiment, the irradiation time of the first electromagnetic wave L1 is set to a value equal to or longer than the volume of the glass raw material U, i.e., V mm ３ When the irradiation time is 0.02 × V seconds or more, the irradiation time of the first electromagnetic wave L1 is preferably 0.02 × V seconds or more. The irradiation time of the first electromagnetic wave L1 is more preferably 0.04 × V seconds or more, further preferably 0.06 × V seconds or more, and even more preferably 0.08 × V seconds or more. The upper limit of the irradiation time is not particularly limited, but may be 0.3 × V seconds or less from the viewpoint of productivity of the glass.

[0033] <Float Molten Glass Manufacturing Process> FIG. 2 is a flowchart showing an example of a float molten glass manufacturing process according to the first embodiment.

[0034] First, a glass raw material U is placed on a support member 12 (step S1: placing step). Specifically, predetermined raw materials are weighed and press-molded, or melted once and then crystallized to obtain one or more raw material lump. At this time, a slurry dispersed in a liquid dispersion medium may be dried to obtain a cake, which may be pulverized to obtain one or more raw material lump from the powder. Alternatively, the obtained raw material lump may be sintered. In this embodiment, one or more raw material lump, i.e., a glass raw material U, is placed on a support member 12.

[0035] Next, gas is injected onto the glass frit U supported by the support member 12 (Step 2: gas injection step). Specifically, gas is supplied to the glass frit U through supply holes provided in the support member 12. The supply holes are, for example, through holes that penetrate from the outer surface of the support member to the supply surface.

[0036] Next, the frit U supported by the support member 12 is heated (step S3: heating step). In this step, for example, the frit U is irradiated with the first electromagnetic wave L1 to heat the frit U until it reaches a desired temperature. For example, the first heating device simultaneously irradiates the frit U with multiple laser beams, which are the first electromagnetic wave L1, to raise the temperature of the frit U. As a result, the frit U melts and becomes a molten liquid. Note that the heating step in this step is not limited to the heating method using the first electromagnetic wave L1. In addition, the gas ejection step in step S2 may be started after the heating step in step S3 is started.

[0037] Next, the frit U supported by the support member 12 is supported in a non-contact manner (step S4: non-contact supporting step). In step S2, gas is sprayed onto the frit U, causing the frit U to separate from the support member 12 and the frit U in a molten state to float up. In other words, the frit U in a molten state is supported in a non-contact manner by providing gas in a first space between the frit U and the support member 12 provided below the frit U. Note that when the support member 12 has a through-hole, the "first space between the support member 12 and the frit U" refers to the space between the frit U and the upper surface of the support member 12 having the through-hole.

[0038] For example, the support member 12 supports the molten glass frit U in a non-contact state for a period of time equal to or longer than a predetermined period starting from the timing when the glass frit U is floated from the support member 12 by the gas blown through the through-holes. In addition, the light source 13 irradiates the non-contact-supported glass frit U with a first electromagnetic wave L1. As a result, a convection state occurs inside the non-contact-supported glass frit U.

[0039] The support member 12 supports the glass raw material U at a temperature of V mm ３ The glass frit U in a molten state is supported in a non-contact manner and irradiated with the first electromagnetic wave L1 for a continuous period of 0.02 × V seconds or more as the time, and when the above-mentioned time is exceeded, the non-contact supporting of the glass frit U may be continued or interrupted, and the irradiation of the first electromagnetic wave L1 or heating by another method may be continued or stopped.

[0040] The viscosity of the non-contact supported frit U is preferably 0.1 Pa s or less, more preferably 0.07 Pa s or less, and even more preferably 0.04 Pa s or less. By setting the viscosity to such a level, convection inside the frit U occurs more effectively, and the occurrence of striae can be efficiently suppressed. The lower limit of the viscosity of the non-contact supported frit U is not particularly limited, but may be 0.01 Pa s or more from the viewpoint of stably supporting the frit U in a non-contact manner.

[0041] For example, the temperature of the glass frit U irradiated with the first electromagnetic wave L1 is equal to or higher than the glass liquidus temperature. The output of the light source 13 may be sufficient to maintain the glass frit U in a molten state, and is, for example, 50 W or higher when a carbon dioxide gas laser is used.

[0042] Next, the temperature of the frit U is lowered (Step S5: Temperature Lowering Step). Specifically, by suppressing heating by laser irradiation or the like in the heating step, the temperature of the frit U in a non-contact state is lowered so that the temperature of the frit U in a molten state is lowered to below the glass transition point. Heating suppression includes reducing the output of the laser light used for heating, reducing the number of laser beams irradiated onto the frit U from among the multiple laser beams, and stopping the laser beam irradiation. When reducing the number of laser beams irradiated onto the frit U from among the multiple laser beams, the laser beam irradiation may be stopped sequentially from one end of the glass, or the laser beam irradiated onto the peripheral portion of the glass may be stopped before the laser beam irradiated onto the center portion of the glass, or the irradiation may be stopped in the reverse order. In this step, the levitation of the frit U may be stopped before or after the completion of cooling. This completes the manufacturing process of the float molten glass.

[0043] For example, in the manufacturing process of floating molten glass, the bottom of the frit U in contact with the support member 12 may experience a slower temperature rise than other parts, resulting in the formation of a non-uniform composition region due to crystallization or the like. Even if the non-uniform composition region is subsequently melted, if the frit U is cooled without sufficient homogenization during melting, this can be one of the causes of striae. By supporting the frit U in a non-contact manner for a predetermined period of time, the crystallized portion and the non-uniform composition region caused by crystallization move due to convection inside the frit U, thereby promoting the homogenization of the non-uniform composition region and suppressing the occurrence of striae.

[0044] In this embodiment, the glass frit U in a molten state may be supported in a non-contact manner for a predetermined period of time. For example, the glass frit U may be heated to a molten state, then the heating may be stopped, and the temperature of the glass frit U may be reduced to a glass transition point or less to partially vitrify the glass frit U. Then, the glass frit U may be heated again to a molten state, and the non-contact manner may be supported for a predetermined period of time.

[0045] <Second embodiment: irradiation of first electromagnetic wave L1 and second electromagnetic wave L2> <Outline of manufacturing apparatus 10>

[0046] Next, a glass manufacturing apparatus 10 according to a second embodiment will be described. FIG. 3 is a schematic diagram of the manufacturing apparatus 10 including a support member 12 according to the second embodiment. Differences from the first embodiment will be described below. The glass manufacturing apparatus 10 according to this embodiment includes both a light source 13 and a light source 23. The light source 23 emits a second electromagnetic wave L2 having a wavelength of 400 nm or more and less than 5000 nm. That is, the glass manufacturing apparatus 10 according to this embodiment performs both irradiation of a first electromagnetic wave L1 by the light source 13 and irradiation of a second electromagnetic wave L2 by the light source 23. The light source 13 functions as a first heating device for heating the glass frit U, and the light source 23 functions as a second heating device for heating the glass frit U. Although not shown, a mirror may be used as appropriate to guide the first electromagnetic wave L1 and the second electromagnetic wave L2 to the glass frit.

[0047] The light source 23 continuously emits second electromagnetic waves L2 with a wavelength of 400 nm or more but less than 5000 nm. Electromagnetic waves with such wavelengths are translucent to glass. That is, the second electromagnetic waves L2 are partially absorbed by the glass and partially transmitted (i.e., absorbed by the glass with a smaller absorption coefficient). This allows the second electromagnetic waves L2 to be absorbed not only on the surface of the glass but also inside it, resulting in a more uniform temperature throughout the glass. When the temperature throughout the glass becomes more uniform, regions with non-uniform composition within the glass diffuse according to the concentration gradient, making the composition more uniform. In other words, maintaining a more uniform temperature allows the constituent components of the glass to migrate from areas of high concentration to areas of low concentration within the glass, resulting in a more uniform concentration (composition) of the glass components, thereby suppressing the occurrence of striae.

[0048] In this embodiment, the wavelength of the second electromagnetic wave L2 is preferably 400 nm or more and less than 5000 nm, more preferably 600 nm or more and 3500 nm or less, and even more preferably 800 nm or more and 2000 nm or less. By using such a wavelength range, the inside of the melt can be heated more uniformly. As an example of the light source 23, a halogen heater can be used.

[0049] The lower limit of the second absorption coefficient, which is the absorption coefficient of the second electromagnetic wave L2 for the glass raw material U in this embodiment, is preferably 0.01 cm －１ and more preferably 0.1 cm －１ and more preferably 1 cm －１ The upper limit of the second absorption coefficient is preferably 100 cm －１ and more preferably 50 cm －１ and more preferably 10 cm －１ is.

[0050] As described above, when the first electromagnetic wave L1 is irradiated, a temperature gradient is generated, which generates convection within the frit U, and this has the effect of stirring the compositionally heterogeneous region, thereby making the composition within the frit U more homogeneous. At this time, the convection generates areas where the melt moves fast and areas where it moves slowly, resulting in areas where the melt does not move much, and a compositionally heterogeneous region may remain in that area. Furthermore, if a temperature gradient exists within the frit U, a concentration gradient of components may occur within the frit U due to the Soret effect, and a compositionally heterogeneous region may remain. By further irradiating such frit U with the second electromagnetic wave L2 to homogenize the temperature within the frit U, the remaining compositionally heterogeneous region can be diffused, and the occurrence of striae can be further suppressed.

[0051] That is, by first inducing convection with the first electromagnetic wave L1 to make the compositionally heterogeneous region more homogenous, and then homogenizing the temperature with the second electromagnetic wave L2 to further homogenize any remaining compositionally heterogeneous region, an even greater striae effect can be obtained. In addition, the convection caused by the temperature gradient due to the application of the first electromagnetic wave L1 moves glass components faster than the diffusion of components caused by the temperature uniformity due to the application of the second electromagnetic wave L2. Therefore, by combining the first electromagnetic wave L1 and the second electromagnetic wave L2, glass can be obtained with high productivity and with suppressed striae.

[0052] <Manufacturing Process of Floating Molten Glass> As in the manufacturing process of the floating molten glass in the first and second embodiments, the frit U is placed on the support member 12 (Step S1: placing process), and gas is ejected (Step S2: gas ejection process). The frit U supported on the support member 12 is heated (Step S3: heating process). The heating method for melting the frit U to a molten state is not limited. The frit U may be heated by irradiating it with the first electromagnetic wave L1 or the second electromagnetic wave L2. The use of the first electromagnetic wave L1 causes convection due to a temperature gradient, which makes it easier for the unmelted portion to move to the inside of the frit U, thereby enabling the frit U to be melted efficiently.

[0053] Next, the frit U supported by the support member 12 is supported in a non-contact manner (step S4: non-contact supporting step). In step S2, gas is sprayed onto the frit U, causing the frit U to separate from the support member 12 and the frit U in a molten state to float up. In other words, the frit U in a molten state is supported in a non-contact manner by providing gas in a first space between the frit U and the support member 12 provided below the frit U. Note that when the support member 12 has a through-hole, the "first space between the support member 12 and the frit U" refers to the space between the frit U and the upper surface of the support member 12 having the through-hole.

[0054] For example, the support member 12 supports the glass frit U in a molten state in a non-contact manner for a period of time equal to or longer than a predetermined period starting from the timing when the glass frit U is floated from the support member 12 by the gas blown through the through-holes. ３ The glass frit U, at least a part of which has been melted by heating, is supported for a continuous period of 0.02×V seconds or more after it starts to float up from the support member 12.

[0055] In a first example, a contactlessly supported glass raw material U is simultaneously irradiated with a first electromagnetic wave L1 having a wavelength of 100 nm or more and less than 400 nm or 5000 nm or more and less than 10 cm, and with a second electromagnetic wave L2 having a wavelength of 400 nm or more and less than 5000 nm. The irradiation start timings of the first electromagnetic wave L1 and the second electromagnetic wave L2 may be the same or different. After that, the irradiation dose of the first electromagnetic wave L1 is reduced, and then the irradiation of the second electromagnetic wave L2 is stopped. The first electromagnetic wave is stopped earlier than the second electromagnetic wave or simultaneously with the second electromagnetic wave.

[0056] In addition, it is more preferable that the irradiation amount of the first electromagnetic wave L1 after reduction is such that almost no heat is imparted to the glass. For example, when a carbon dioxide gas laser is used as the first heating device, the amount of almost no heat is less than 5 W. By doing so, the effect of making the temperature inside the glass raw material more uniform by the second electromagnetic wave L2 can be more effectively obtained.

[0057] In the first example, before reducing the irradiation of the first electromagnetic wave L1 to the non-contact supported glass frit U, the first electromagnetic wave L1 is applied to the glass frit U until the volume of the glass frit is reduced to V mm ３ It is preferable to continuously irradiate the first electromagnetic wave L1 for 0.02 × V seconds or more as the volume of the glass raw material U. In this way, the compositionally heterogeneous region can be stirred by convection caused by the temperature gradient, and the effect of suppressing the occurrence of striae can be more effectively obtained. ３ When the irradiation time is 0.04 × V seconds or more, the irradiation time is preferably 0.04 × V seconds or more, more preferably 0.06 × V seconds or more, and even more preferably 0.08 × V seconds or more. The upper limit of the irradiation time of the first electromagnetic wave L1 is not particularly limited, but may be 0.3 × V seconds or less from the viewpoint of productivity of the glass.

[0058] Furthermore, it is preferable to continue the irradiation of the second electromagnetic waves L2 for at least 10 seconds after reducing the irradiation of the first electromagnetic waves L1. By doing so, the temperature inside the glass becomes more uniform, the compositionally non-uniform regions are diffused, and the effect of suppressing the occurrence of striae can be more effectively obtained. The irradiation time of the second electromagnetic waves L2 after reducing the irradiation dose of the first electromagnetic waves L1 is preferably 30 seconds or more, more preferably 45 seconds or more, and even more preferably 60 seconds or more. The upper limit of the irradiation time is not particularly limited, but may be 300 seconds or less from the viewpoint of glass productivity.

[0059] In addition, the first electromagnetic wave L1 is applied to the glass raw material with a volume of V mm ３ It is more preferable to continue the irradiation of the second electromagnetic waves L2 for 0.02 × V seconds or more as the irradiation dose of the first electromagnetic waves L1 and to continue the irradiation of the second electromagnetic waves L2 for at least 10 seconds after reducing the irradiation dose of the first electromagnetic waves L1, whereby the effect of suppressing the occurrence of striae can be maximized.

[0060] As a second example, similar to the first example, both the first electromagnetic wave L1 and the second electromagnetic wave L2 are irradiated simultaneously, and after terminating the irradiation of the first electromagnetic wave L1, the irradiation of the second electromagnetic wave L2 is terminated.

[0061] As a third example, after the irradiation of the first electromagnetic wave L1 is stopped, the irradiation of the second electromagnetic wave L2 is started. As a result, it goes without saying that the irradiation of the second electromagnetic wave L2 is stopped after the irradiation of the first electromagnetic wave L1 is stopped.

[0062] In the second and third examples, the first electromagnetic wave L1 is applied to the non-contact supported glass frit U, and the volume of the glass frit is V mm ３ It is preferable to continuously irradiate the first electromagnetic wave L1 for 0.02 × V seconds or more as the volume of the glass raw material U. In this way, the compositionally heterogeneous region is stirred by convection caused by the temperature gradient, and the effect of suppressing the occurrence of striae can be more effectively obtained. The irradiation time of the first electromagnetic wave L1 is set to a value corresponding to the volume of the glass raw material U in V mm ３ When the irradiation time is 0.02 × V seconds or more, the irradiation time is preferably 0.02 × V seconds or more, more preferably 0.04 × V seconds or more, and even more preferably 0.06 × V seconds or more. The upper limit of the irradiation time of the first electromagnetic wave L1 is not particularly limited, but may be 0.3 × V seconds or less from the viewpoint of productivity of the glass.

[0063] Furthermore, it is preferable to continue the irradiation of the second electromagnetic waves L2 for at least 10 seconds after the irradiation of the first electromagnetic waves L1 has stopped. By doing so, the temperature inside the glass becomes more uniform, the compositionally non-uniform regions are diffused, and the effect of suppressing the occurrence of striae can be more effectively obtained. The irradiation time of the second electromagnetic waves L2 after the irradiation of the first electromagnetic waves L1 has stopped is more preferably 30 seconds or more, even more preferably 45 seconds or more, and even more preferably 60 seconds or more. The upper limit of the irradiation time is not particularly limited, but may be 300 seconds or less from the viewpoint of glass productivity.

[0064] In addition, the first electromagnetic wave L1 is applied to the glass raw material with a volume of V mm ３ It is more preferable to continue the irradiation of the second electromagnetic waves L2 for 0.02 × V seconds or more as the irradiation time and to continue the irradiation of the second electromagnetic waves L2 for at least 10 seconds after the irradiation of the first electromagnetic waves L1 has stopped, since this maximizes the effect of suppressing the occurrence of striae.

[0065] The viscosity of the non-contact supported frit U is preferably 0.1 Pa s or less, more preferably 0.07 Pa s or less, and even more preferably 0.04 Pa s or less. By adjusting the viscosity to such a level, the components of the frit U can be more effectively transferred, and the occurrence of striae can be efficiently suppressed. The lower limit of the viscosity of the non-contact supported frit U is not particularly limited, but may be 0.01 Pa s or more from the viewpoint of stably supporting the frit U in a non-contact state. As an example, the temperature of the non-contact supported frit U in a molten state is equal to or higher than the glass liquidus temperature.

[0066] From the viewpoint of making the temperature inside the glass more uniform, the area of ​​the irradiation region (hereinafter also referred to as "spot") of the second electromagnetic wave L2 formed on the surface of the molten frit U in a plan view in the gravity direction is preferably 10% or more, more preferably 50% or more, and even more preferably 100% of the total area of ​​the molten frit U in a plan view in the gravity direction. If the spot formed on the surface of the molten frit U by the second electromagnetic wave L2 is substantially circular, the diameter of the spot is preferably 30% or more, more preferably 70% or more, and even more preferably 100% of the diameter of the molten frit U in a plan view in the gravity direction. If the diameter is 100%, the irradiation region may extend beyond the glass.

[0067] From the viewpoint of making the temperature inside the glass more uniform, the light sources 23 may be arranged in a rotationally symmetrical manner. Furthermore, the temperature distribution within the irradiation area of ​​the light sources 23 may be appropriately adjusted. For example, the irradiation light of the second electromagnetic wave L2 irradiated by the light sources 23 may be top-hat shaped, and the output of the outer peripheral portion may be stronger in response to the fact that the temperature of the glass raw material decreases from the outside where it comes into contact with the outside air.

[0068] By continuing to irradiate the second electromagnetic wave L2 after terminating the irradiation of the first electromagnetic wave L1, if an inhomogeneous region occurs due to the irradiation of the first electromagnetic wave L1, the inhomogeneous region is diffused by the irradiation of the second electromagnetic wave L2, thereby suppressing the occurrence of striae. Note that even when the irradiation dose of the first electromagnetic wave L1 is reduced and the second electromagnetic wave L2 is irradiated, at some stage the diffusion effect of the second electromagnetic wave L2 becomes dominant over the convection effect of the first electromagnetic wave L1. As a result, even if an inhomogeneous region occurs due to the irradiation of the first electromagnetic wave L1, the inhomogeneous region can be diffused by the irradiation of the second electromagnetic wave L2.

[0069] Additionally, as described above, the first electromagnetic wave L1 has a wavelength that is easily absorbed by glass. Furthermore, the second electromagnetic wave L2 is partially absorbed by glass and partially transmitted. That is, the absorption coefficient of the second electromagnetic wave L2 is smaller than that of the first electromagnetic wave L1. The non-contact supported glass raw material U is irradiated with at least the first electromagnetic wave L1, and after reducing or stopping the irradiation of the first electromagnetic wave L1, the irradiation of the second electromagnetic wave L2, whose absorption coefficient is smaller than that of the first electromagnetic wave L1, is stopped. In this way, if a compositionally heterogeneous region occurs due to a temperature gradient caused by the irradiation of the first electromagnetic wave L1, the temperature inside the glass is made more uniform by the irradiation of the second electromagnetic wave L2, thereby diffusing the compositionally heterogeneous region and suppressing the occurrence of striae.

[0070] <Third embodiment: irradiation of second electromagnetic wave L2> <Outline of manufacturing apparatus 10> Next, a glass manufacturing apparatus 10 according to a third embodiment will be described. Differences from the first and second embodiments will be described below. The manufacturing apparatus 10 according to the third embodiment differs from the manufacturing apparatus 10 according to the first embodiment in FIG. 1 in that it has a light source 23 instead of the light source 13 and the mirrors 14 and 15.

[0071] The glass manufacturing apparatus 10 in this embodiment supports the glass frit U in a molten state in a non-contact manner for 10 seconds or more. Furthermore, the glass manufacturing apparatus 10 in this embodiment continuously irradiates the glass frit U supported in a non-contact manner with a second electromagnetic wave L2 having a wavelength of 400 nm or more and less than 5000 nm for 10 seconds or more. As described above, when the second electromagnetic wave is irradiated, the temperature inside the glass becomes uniform, thereby diffusing the non-uniform region of composition and making the composition inside the glass frit U more uniform.

[0072] In this embodiment, the wavelength of the second electromagnetic wave L2 is preferably 400 nm or more and less than 5000 nm, more preferably 600 nm or more and 3500 nm or less, and even more preferably 800 nm or more and 2000 nm or less. By using such a wavelength range, the inside of the melt can be heated more uniformly. As an example, a halogen heater can be used as the light source 23.

[0073] The lower limit of the second absorption coefficient, which is the absorption coefficient of the second electromagnetic wave L2 for the glass raw material U in this embodiment, is preferably 0.01 cm －１ and more preferably 0.1 cm －１ and more preferably 1 cm －１ The upper limit of the second absorption coefficient is preferably 100 cm －１ and more preferably 50 cm －１ and more preferably 10 cm －１ is.

[0074] In the present embodiment, the irradiation time of the second electromagnetic wave L2 is preferably 10 seconds or more, more preferably 30 seconds or more, even more preferably 45 seconds or more, and even more preferably 60 seconds or more. The upper limit of the irradiation time is not particularly limited, but may be 300 seconds or less from the viewpoint of productivity of the glass.

[0075] <Manufacturing Process of Floating Molten Glass> As in the manufacturing process of floating molten glass in the first embodiment, the glass frit U is placed on the support member 12 (Step S1: placing process), and gas is ejected (Step S2: gas ejection process). In addition, the glass frit U supported on the support member 12 is heated (Step S3: heating process). When melting the glass frit U to bring it into a molten state, the heating method is not limited. The glass frit U may be heated by irradiating it with the second electromagnetic wave L2.

[0076] Next, the frit U supported by the support member 12 is supported in a non-contact manner (step S4: non-contact supporting step). In step S2, gas is sprayed onto the frit U, causing the frit U to separate from the support member 12 and the frit U in a molten state to float up. In other words, the frit U in a molten state is supported in a non-contact manner by providing gas in a first space between the frit U and the support member 12 provided below the frit U. Note that when the support member 12 has a through-hole, the "first space between the support member 12 and the frit U" refers to the space between the frit U and the upper surface of the support member 12 having the through-hole.

[0077] For example, the support member 12 supports the glass frit U in a contactless manner for a predetermined period or longer starting from the timing when the glass frit U is floated from the support member 12 by the gas blown through the through-holes. In addition, the light source 23 irradiates the glass frit U supported in a contactless manner with a second electromagnetic wave L2.

[0078] That is, the support member 12 continues to irradiate the second electromagnetic wave L2 for a period of 10 seconds while non-contact supporting the glass frit U, thereby maintaining the molten state. When the above-mentioned time has elapsed, the non-contact supporting of the glass frit U may be continued or interrupted, and the irradiation of the second electromagnetic wave L2 or heating by another method may be continued or stopped.

[0079] The viscosity of the frit U supported by the support member 12 in a non-contact manner is preferably 0.1 Pa s or less, more preferably 0.07 Pa s or less, and even more preferably 0.04 Pa s or less. By setting the viscosity in this range, the components of the frit U can be more effectively transferred, and the occurrence of striae can be efficiently suppressed. The lower limit of the viscosity of the frit U supported in a non-contact manner is not particularly limited, but may be 0.01 Pa s or more from the viewpoint of stably supporting the frit U in a non-contact manner.

[0080] In this embodiment, the manufacturing apparatus 10 may include a light source 13 and mirrors 14 and 15. In this embodiment, when irradiating the first electromagnetic wave L1 simultaneously with the second electromagnetic wave L2, it is more preferable that the irradiation amount of the first electromagnetic wave L1 be such that it hardly heats the glass. Irradiation that hardly heats the glass means, for example, irradiation of less than 5 W when using a carbon dioxide laser. In this embodiment, it is even more preferable that the first electromagnetic wave is not irradiated after the start of irradiation of the second electromagnetic wave L2. By doing so, the effect of uniforming the temperature inside the glass frit by the second electromagnetic wave L2 can be effectively achieved. As an example, the temperature of the glass frit U in a molten state supported without contact is equal to or higher than the glass liquidus temperature. The output of the light source 23 is sufficient to maintain the glass in a molten state, and is, for example, 200 W or higher when using a halogen heater.

[0081] In addition, the manufacturing apparatus 10 of this embodiment uses electromagnetic waves with wavelengths that are translucent to glass, thereby making the temperature inside the molten glass raw material U more uniform. However, by using the method described below under appropriate conditions, it is also possible to make the temperature inside the glass raw material U more uniform.

[0082] As an example, by using a heating method that can provide heat to the inside of the glass frit U, the temperature inside the glass frit U can be made more uniform. As an example of this heating method, induction heating can be mentioned. By configuring the outer periphery of the melt to be covered with an induction heating coil, the inside of the glass frit can be heated more efficiently and uniformly. As another example, microwave heating can be mentioned. For example, by configuring the melt to be irradiated with microwaves from the periphery, the inside of the glass frit can be heated more efficiently and uniformly.

[0083] As another example, the temperature inside the glass can be made more uniform by placing the molten glass raw material in a high-temperature atmosphere. For example, the manufacturing apparatus 10 or the support member 12 can be placed in a heating furnace to be placed in a high-temperature atmosphere. Alternatively, for example, hot air can be blown around the glass raw material U, heating can be performed with a burner, or the flotation gas can be heated to a high temperature. In this case, the temperature of the atmosphere is preferably 500°C or higher but lower than 2000°C, from the viewpoint of maintaining the glass in a molten state.

[0084] As another example, it is possible to make the temperature inside the glass more uniform by suppressing the heat loss from the molten glass frit U. For example, by covering the periphery of the glass frit U with a heat-reflecting material, the temperature inside the heat-reflecting material becomes more uniform.

[0085] In order to make the temperature inside the glass raw material more uniform, the above configurations may be combined.

[0086] <Fourth embodiment: cooling device> Next, a glass manufacturing apparatus 10 according to a fourth embodiment will be described. Fig. 5 is a schematic diagram of the manufacturing apparatus 10 including a support member 12 according to the fourth embodiment. Differences from the first embodiment will be described below. The glass manufacturing apparatus 10 according to this embodiment has a cooling device 24 for the support member 12. The cooling device 24 reduces the temperature of the support member 12.

[0087] As one example, the cooling device 24 is a device that sends a fluid as a refrigerant into a flow path of the support member 12. The fluid is, for example, water or air. The temperature of the support member 12 decreases as the refrigerant passes through the flow path. As another example, the cooling device 24 is a device that cools the support member 12 using a Peltier element. The cooling device 24 that has a Peltier element cools, for example, a portion of the outer wall of the support member 12 from the outside. As another example, the cooling device is a device that lowers the temperature of the support member 12 by blowing cool air onto the support member 12.

[0088] This configuration can reduce the temperature of the support member 12. For example, when mass-producing glass using the float melting method, glass raw materials are repeatedly heated over a long period of time, which causes heat to accumulate in the support member 12, resulting in a high temperature. By providing the cooling device 24, it is possible to prevent the support member 12 from becoming too hot.

[0089] Furthermore, for example, the cooling device 24 in this embodiment may be combined with the above-described embodiment. In the above-described embodiment, when the first electromagnetic wave L1 and the second electromagnetic wave L2 are irradiated onto the molten glass raw material for a long period of time, the temperature of the support member 12 may become high. In particular, when a light source 23 with a large heating diameter, such as a halogen heater, is used, if the light directly hits the support member 12, the support member 12 is directly heated, and the support member 12 is likely to become even hotter. By including the cooling device 24 in the glass manufacturing apparatus 10, the support member 12 can be prevented from becoming too hot.

[0090] Generally, the viscosity and surface tension of a liquid decrease as the temperature increases. If the support member 12 becomes too hot, the melt temperature rises excessively, and the decrease in viscosity and surface tension makes it difficult to maintain a constant melt shape and stable floating. As a result, the glass frit U may deform or move, resulting in contact with or fusion to the support member 12. If the glass frit U in a molten state comes into contact with or fuses to the support member 12, crystallization may occur, and if crystallization occurs, glass of good quality cannot be obtained. In this embodiment, by preventing the support member 12 from becoming too hot, the glass frit U can be stably supported without contact and maintained in a molten state for a relatively long period of time. Therefore, stable mass production of glass is possible. By combining this with the above-mentioned embodiment, striae can be more reliably reduced.

[0091] The timing at which the cooling device 24 cools the support member 12 is not limited, and the cooling can be performed at any timing, not limited to the heating step of step S3.

[0092] 6 is an example of a schematic diagram illustrating a cooling device 24 according to a fourth embodiment. The glass manufacturing apparatus 10 shown in this figure has a fixing member 25. The fixing member 25 is provided above the support member 12 and fixes the support member 12 to the stage 11. For example, as shown in this figure, the fixing member 25 has a horizontal surface 25a that covers a portion of the support member 12 and a side surface 25b that is connected vertically to the end of the horizontal surface 25a, and the horizontal surface 25a is open near the center so as to expose the concave surface R of the support member 12.

[0093] The stage 11 shown in the figure includes a nozzle 111 connected to the gas flow regulator 20 and feeding gas into the support member 12, and a fixing wall 112 standing approximately vertically upward. The nozzle 111 supplies gas for floating the glass frit U to the glass frit U through a supply hole in the support member 12. The fixing wall 112 has, for example, a circular cross section in the horizontal direction, and has the function of isolating a space filled with gas so that the gas ejected from the nozzle 111 does not leak to the outside.

[0094] The support member 12 includes a base 121 that supports the glass frit U and a locking portion 122 that locks to the stage 11. The locking portion 122 is locked to the upper portion of the fixing wall 112. That is, the stage 11 supports the support member 12 from below. The base 121 is located inside the fixing wall 112. As shown in FIG. 6 , there may be a gap between the base 121 and the fixing wall 112. For example, if a hole for introducing gas is present on the side surface of the base 121, the presence of the gap allows the gas to be ejected from the hole on the side surface to the concave surface R. Note that there may be no gap between the base 121 and the fixing wall 112.

[0095] The cooling device 24 lowers the temperature of the support member 12 by sending a coolant into a flow path (not shown) provided in the support member 12. The cooling device 24 may also lower the temperature of the fixing member 25 and the support member 12 in contact with the fixing member 25 by sending a coolant into a flow path (not shown) provided in the fixing member 25. The cooling device 24 may also cool the stage 11.

[0096] The support member 12 may be made of a material with high thermal conductivity. This configuration improves cooling efficiency. For example, the support member 12 may be made of alloys such as stainless steel, aluminum alloys, and brass, or titanium, aluminum, copper, platinum, carbon, etc. Also, the support member 12 may be made of a material with high reflectivity, or the concave surface R may be coated with a material with high reflectivity, so as to make it less likely to absorb heat.

[0097] <Glass Composition and Properties> The above-described embodiments can be applied to the production of glass of a desired composition.

[0098] The glass produced according to this embodiment contains, in mol %, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ The total content of (Li ２ O+K ２ O + Na ２O+P ２ O ５ +B ２ O ３ +WO ３ +As ２ O ３ ) is preferably 10% or less, more preferably 5% or less, even more preferably 3% or less, and even more preferably substantially free. "Substantially free" means that the content is equal to or less than the level of an impurity, and specifically, for example, 100 ppm or less.

[0099] When glass is melted, the glass raw materials reach a temperature of around 1500°C. ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ When the contained components are gasified by sublimation or boiling point at a relatively low temperature, the composition in the glass becomes non-uniform, which causes striae. ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ By setting the total content of K in this range, striae can be further suppressed. ２ O, Na ２ O, P ２ O ５ are known to sublime at relatively low temperatures of 1275°C, 350°C, and 350°C, respectively. ２ O ３ , W.O. ３ , As ２ O ３ are known to reach their boiling points at relatively low temperatures of 1800°C, 1837°C, and 465°C, respectively.

[0100] Furthermore, although this embodiment can be applied to the production of glass of a desired composition, there are compositions that can be more suitably produced by this embodiment. The glass produced by this embodiment contains, in mol %, B ２ O ３ , SiO ２ , P ２ O ５ and As ２ O ３ The total content of (B ２ O ３ +SiO ２ +P ２ O ５ +As ２ O ３ ) is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less. When the glass raw material U is melted in contact with a container such as a crucible, such a composition tends to cause problems such as crystallization, making production difficult. In this embodiment, in which the raw material lump is floated and melted in a non-contact state, vitrification is easier than when a container such as a crucible is used, and this composition can significantly improve productivity.

[0101] Also, in mol%, La ２ O ３ , BaO, CaO, MgO, Y ２ O ３ , Gd ２ O ３ , Al ２ O ３ , TiO ２ , Nb ２ O ５ , ZrO ２ and Ta ２ O ５ Total content (La ２ O ３ +BaO+CaO+MgO+Y ２ O ３ +Gd ２ O ３ +Al ２ O ３ + TiO ２ +Nb ２ O ５ + ZrO ２ +Ta ２ O ５) is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. When the glass raw material U is melted in contact with a container such as a crucible, such a composition tends to cause problems such as crystallization, making production difficult. In this embodiment, in which the raw material lump is floated and melted in a non-contact state, vitrification is easier than when a container such as a crucible is used, and this composition can significantly improve productivity.

[0102] It is more preferable that the glass produced by this embodiment is substantially free of boron (B). It is also more preferable that the glass produced by this embodiment is an optical glass.

[0103] In addition, the glass produced according to the present embodiment has a partial dispersion ratio (P ｇ，Ｆ ) and Abbe number (ν ｄ ) is P ｇ，Ｆ ≦−0.0042×ν ｄ +0.7193 and the wavelength (λ ８０ ) and Abbe number (ν ｄ ) is λ ８０ ≦−10.253×ν ｄ +672.5, and the glass transition temperature T ｇ and the difference ΔT between the crystallization onset temperature and the glass transition temperature ≦230°C.

[0104] Glass having the physical properties described above is prone to problems such as crystallization when the glass raw material U is melted in contact with a container such as a crucible, making vitrification difficult and tending to result in significant striae. By producing glass according to the present embodiment, in which the raw material mass is suspended and melted in a non-contact state, vitrification becomes easier than when a container such as a crucible is used for production, and the occurrence of striae can be suppressed.

[0105] The size of the glass produced by this embodiment is not particularly limited, but the length in the major axis direction is preferably 4 mm or more, more preferably 8 mm or more, and even more preferably greater than 10 mm. The weight is preferably 400 mg or more, more preferably 1000 mg or more. The upper limit of the weight is preferably 10,000 mg or less, more preferably 6,000 mg or less.

[0106] The volume of glass increases as the cube of the diameter, and the larger the volume, the more serious the problem of striae. This is because a large volume tends to produce a larger temperature gradient between the inside and outside of the melt when the melt is cooled, which increases the possibility of the glass components solidifying non-uniformly and causing striae. Furthermore, glass with a diameter of more than 10 mm has expanded industrial applications. From this perspective, there is a strong demand for glass with a diameter of more than 10 mm and in which striae are suppressed.

[0107] <Outline of glass properties and measurement methods>

[0108] In the glass manufactured according to this embodiment, the first index, which is the difference between the maximum and minimum values ​​of the optical path length corresponding to a length of 1 mm in the glass, is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. The method for measuring the optical path length of the glass is not limited, and the length in any direction inside the glass may be used to measure the optical path length. The optical path length when traversing the inside of the glass in a first direction is measured. As an example, the first direction is the direction of gravity, based on the attitude of the glass when floating during manufacturing. As another example, the first direction is a horizontal direction perpendicular to the direction of gravity. Here, "optical path length corresponding to a length of 1 mm in the glass" is synonymous with the distance light travels in a vacuum in the same time as it travels 1 mm in the glass.

[0109] 7A and 7B are diagrams showing an example of a method for measuring a first index. Fig. 7A is an example of a side view of glass before processing by the first measurement method, Fig. 7B is an example of a side view of glass after processing by the first measurement method, Fig. 7C is an example of a plan view for explaining a measurement target region R1 by the first measurement method, Fig. 7D is an example of a plan view of glass before processing by the second measurement method, Fig. 7E is an example of a plan view of glass after processing by the second measurement method, and Fig. 7F is an example of a side view for explaining a measurement target region R2 by the second measurement method.

[0110] The first measurement method (horizontal cut) will be described. Glass produced by the floating melting method is usually not a perfect sphere due to the influence of gravity, but is rounded overall, but has a shape that is slightly flattened in the direction of gravity. As shown in FIG. 7(A), portions of the upper and lower sides of the glass are removed so that the upper and lower surfaces of the glass are approximately parallel. As a result, as shown in FIG. 7(B), two opposing surfaces of the glass (surfaces T1 and T2) become approximately parallel. The first index can be a value obtained by dividing the difference between the maximum and minimum values ​​of the optical path length when crossing the two opposing surfaces (surfaces T1 and T2) perpendicularly to the two opposing surfaces by the distance between the two opposing surfaces.

[0111] It is preferable to exclude the periphery (side surface) of the glass from the measurement target because accurate measurement is difficult there. That is, as shown in Figure 7(C), when viewed from a direction perpendicular to the two opposing surfaces of the glass (i.e., surface T1 and surface T2), a circular region occupying 50% to 80% of the area from the center may be set as the measurement target region R1, and the rest of the area outside this may be excluded from the measurement target.

[0112] Next, the second measurement method (vertical cut) will be described. As shown in Figures 7(D) and 7(E), two planes are cut parallel to the direction of gravity so as to remove the left and right arc portions. The first index can be the value obtained by dividing the difference between the maximum and minimum values ​​of the optical path length when crossing two opposing planes (planes T3 and T4) perpendicularly to the two opposing planes by the distance between the two opposing planes.

[0113] It is preferable to exclude the periphery (side surface) of the glass from the measurement target because it is difficult to measure accurately. That is, as shown in Figure 7(F), when viewed from a direction perpendicular to the two opposing surfaces of the glass (i.e., surfaces T3 and T4), an arbitrary circular region may be set as the measurement target region R2, and the area outside this may be excluded from the measurement target.

[0114] Next, the third measurement method (no cutting) will be described. Unlike the first and second measurement methods, the third measurement method does not involve cutting the glass parallel to two surfaces. The first index can be the difference between the maximum and minimum values ​​of the optical path length when traversing the interior of the glass in a first direction, divided by the length in the first direction.

[0115] Note that, in the above, an example of the method for measuring the first index has been explained using the case where the shape of the glass is "rounded overall but slightly flattened in the direction of gravity" as shown in Figure 7, but the above measurement method can also be applied to glass of other shapes, for example, glass after being formed into a desired shape.

[0116] In addition, when the direction substantially perpendicular to the plane along the long axis direction of the glass is defined as the first direction, the first index (first index in the long axis direction) is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. When the glass has a shape that is "rounded overall but slightly flattened in the direction of gravity" as shown in FIG. 7, the first index in the long axis direction can be measured, for example, by the first measurement method. From the viewpoint of obtaining glass in which striae are suppressed, a smaller first index in the long axis direction is more preferable, and the lower limit is not particularly limited, but it can be 1 nm or more, 3 nm or more, or 5 nm or more, taking into account the balance between various factors such as the required quality and production costs.

[0117] In addition, the glass in this embodiment has a refractive index difference between the maximum and minimum refractive indices of 100×10 －６ Preferably, it is 80×10 or less. －６ More preferably, it is 50×10 or less. －６The refractive index difference can be calculated using the first index. For example, if the first index is 40 nm, the refractive index difference is 40×10 －６ From the viewpoint of obtaining glass with suppressed striae, it is more preferable that the difference between the maximum refractive index and the minimum refractive index in the glass is small, and the lower limit is not particularly limited, but it is preferable to set it to 1 × 10 in consideration of the balance between various factors such as the required quality and manufacturing costs. －６ It can be more than 3 × 10 －６ It can be more than 5 × 10 －６ It can also be more than that.

[0118] Additionally, the glass produced by this embodiment preferably has a second index, which is the standard deviation (RMS) of the optical path length corresponding to a length of 1 mm in the glass, of 15 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. The second index is calculated from the standard deviation (RMS) of the optical path length corresponding to a length of 1 mm when traversing the interior of the glass in a first direction. The second index can be calculated, for example, by measuring the optical path length inside the glass in the same manner as the first, second, and third measurement methods described above for the first index, and determining the standard deviation of the optical path length corresponding to the measured length of 1 mm.

[0119] When the direction substantially perpendicular to the surface along the long axis of the glass is defined as the first direction, the second index (second index in the long axis direction) is preferably 15 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. When the shape of the glass is "rounded overall but slightly flattened in the direction of gravity" as shown in Figure 7, the second index in the long axis direction can be measured, for example, by measuring the optical path length inside the glass in the same manner as in the first measurement method and determining the standard deviation of the optical path length corresponding to a measured length of 1 mm.

[0120] In addition, the glass produced by this embodiment has a standard deviation of the refractive index in the glass of 15×10 －６ Preferably, it is 10×10 or less. －６ More preferably, it is 5×10 or less. －６The refractive index distribution can be calculated using the second index. For example, when the second index is 8 nm, the refractive index distribution is 8×10 －６ In measuring the optical path length and refractive index described above, a wavelength of 632.8 nm, which is the wavelength output by a He—Ne laser, may be used as a reference.

[0121] <Simulation of Flow Velocity and Temperature Distribution> Next, the results of a fluid simulation performed on the glass of this embodiment regarding the flow velocity distribution and temperature distribution will be described.

[0122] Figure 8 shows the results of a fluid simulation (part 1). Figure 8(A) shows the irradiation position when a single laser beam is irradiated, Figure 8(B) shows the flow velocity distribution when a single laser beam is irradiated, and Figure 8(C) shows the temperature distribution when a single laser beam is irradiated. Note that V1 in Figure 8(A) indicates the laser irradiation position in the simulation.

[0123] In the following examples, the number of laser irradiation points on the glass frit U does not necessarily indicate the number of lasers. For example, as shown in Fig. 8, when the glass frit U is irradiated with a laser at one point, one laser may be irradiated on the part, or multiple lasers may be irradiated on the part at the same time in order to obtain enough heat to keep the glass frit in a molten state.

[0124] To simulate the flow inside the melt, a thermal fluid analysis was performed using the thermal fluid analysis software Ansys Fluent. The melt model was an approximately spherical shape with a diameter of 15 mm and a thickness of 6.5 mm, and the surface shape was fixed to perform a steady-state analysis. The density d (kg / m ３ ), thermal conductivity λ (W / m K), and viscosity coefficient η (kg / m s) were all set as functions of temperature T (K) as follows: d = -0.2T + 5200 λ = 4.17 × 10 －５ T ２ -4.22 x 10 －２ T+11.70 log １０ (η)=-1.63+247 / T

[0125] In addition, the specific heat Cｐ was set to a constant of 1300 J / kg·K.

[0126] The boundary conditions were set as follows: The laser irradiation area in the melt had a heat flux of 3.0 × 10 ７ W / m ２ The upper surface of the melt, excluding the laser irradiation area, is subjected to a heat flux of 0 (W / m ２ ), and the heat transfer coefficient on the bottom surface of the melt is 10,000 W / m ２ The free flow temperature was 1500 K. The effect of Marangoni convection due to the temperature dependence of surface tension was also taken into consideration, and the Marangoni stress on the entire surface was set to -1 × 10 －５ The value was set to N / m·K.

[0127] Figure 8(B) confirms that sufficient convection exists inside the non-contact supported glass. In particular, it was confirmed that convection occurs faster in the peripheral area than in the center of the glass. Furthermore, Figure 8(C) confirms that there is a bias in the temperature distribution inside the glass.

[0128] 9 and 10 are fluid simulations assuming the case where multiple lasers are used and each laser is irradiated at a different position on the glass raw material. FIG. 9 is a diagram (part 2) showing the results of the fluid simulation. FIG. 9(A) shows the irradiation positions when three lasers are irradiated, FIG. 9(B) shows the flow velocity distribution when three lasers are irradiated, and FIG. 9(C) shows the temperature distribution when three lasers are irradiated. Note that V1, V2, and V3 shown in FIG. 9(A) all indicate the laser irradiation positions in the simulation.

[0129] Figure 10 is a diagram (part 3) showing the results of fluid simulation. Figure 10(A) shows the irradiation position when four laser points are irradiated, Figure 10(B) shows the flow velocity distribution when four laser points are irradiated, and Figure 10(C) shows the temperature distribution when four laser points are irradiated. V1, V2, V3, and V4 shown in Figure 10(A) all indicate the laser irradiation positions in the simulation. The simulation was performed in the same way as when irradiating a single point on the glass raw material surface.

[0130] 9(B) and 10(B) confirmed that sufficient convection exists inside the non-contact supported glass sheet in both three-point and four-point irradiation. In particular, convection occurs faster in the peripheral area of ​​the glass sheet than in the central area. Furthermore, FIGS. 9(C) and 10(C) confirmed that there is a bias in the temperature distribution inside the glass sheet in both three-point and four-point irradiation. Therefore, it was confirmed that sufficient convection occurs even if multiple laser irradiation positions are used.

[0131] From the above flow velocity and temperature distribution simulation, it can be inferred that, by continuously supporting the molten glass raw material U in a non-contact state for a predetermined period in the manufacturing apparatus 10 of this embodiment, crystals inside the glass move due to convection and the mixing of materials due to convection is promoted. In other words, it can be inferred that the movement of the non-uniform composition region that causes striae is promoted, and the occurrence of striae can be suppressed. Furthermore, it was confirmed that temperature distribution and convection can be generated in the glass regardless of the laser irradiation position and number of irradiation points.

[0132] Examples Next, each example will be described, but the present invention is not limited to the following examples in any way.

[0133] Examples 1 to 13, Comparative Examples 1 to 3 First, glass frit U, obtained by weighing oxide raw materials (described separately) to achieve a predetermined chemical composition, was placed on the support member 12 of the manufacturing apparatus 10. Next, a carbon dioxide gas laser with a wavelength of 10.6 μm was irradiated from above and heated while air was sprayed through the through-holes. Two to four carbon dioxide gas lasers with an output of 60 W to 120 W were used to maintain the glass frit in a molten state. After the glass frit U separated from the upper surface of the support member 12, the glass frit U was supported without contact for a supporting time (described separately). After the supporting time (described separately), the glass frit U was vitrified to obtain glass. As described separately, the weight and diameter of the glass were measured with or without pressing. Note that "pressing" here refers to a molding press in which glass is shaped with a molding member to change the shape of the glass. Even when a molding press is performed, the first and second indices can be measured in the same way.

[0134] Example 14 First, glass frit U, obtained by weighing oxide raw materials described separately to achieve a predetermined chemical composition, was placed on the support member 12 of the manufacturing apparatus 10. Next, a carbon dioxide laser was irradiated from above while air was sprayed through the through-holes. After heating to a molten state, six halogen heaters with a peak wavelength of 1 μm and an output of 450 W were irradiated, while three carbon dioxide lasers with an output of 70 W were irradiated. The carbon dioxide laser irradiation was stopped 90 seconds after the glass frit U separated from the upper surface of the support member 12. After the carbon dioxide laser irradiation was stopped, the halogen heater irradiation was continued for 30 seconds, after which the halogen heater irradiation was stopped, and the glass was cooled and vitrified to obtain glass. The glass was not pressed and the weight and diameter of the glass were measured in an unprocessed state.

[0135] Thereafter, the upper and lower surfaces were removed according to the first measurement method so as to obtain the processed thicknesses separately described for Examples 1 to 11 and 14 and Comparative Examples 1 to 3, thereby obtaining a shape similar to that shown in FIG. 7B. When viewed from a direction perpendicular to the upper surface T1 and the lower surface T2, a circular region occupying an area of ​​a separately described percentage from the center was determined as the measurement target region R1. In the table below, this percentage is referred to as the "trimming range (%)," and the diameter of the circular region is referred to as the "trimming range (mm)."

[0136] For Examples 12 and 13, the specimens were cut in the direction of gravity according to the second measurement method to obtain the processed thicknesses described separately, resulting in a shape similar to that shown in Figure 7(E). When viewed from a direction perpendicular to planes T3 and T4, the measurement target region R2 was a circular region occupying an area from the center that was determined to be a separately described percentage. In the table below, the diameter of the circular region is referred to as the "trimming range (mm)."

[0137] The optical path lengths within measurement region R1 and measurement region R2 were measured using a Verifire ™ST interferometer (measurement wavelength: 632.8 nm) manufactured by Zygo Corporation. For Examples 1 to 11, 14, and Comparative Examples 1 to 3, a first index was measured in measurement region R1. The first index was the difference between the maximum and minimum optical path lengths when perpendicularly crossing surfaces T1 and T2, divided by the distance between surfaces T1 and T2. A second index was also measured, which was the standard deviation of the optical path lengths corresponding to a length of 1 mm when perpendicularly crossing surfaces T1 and T2. For Examples 12 and 13, a first index was measured in measurement region R2. The first index was the difference between the maximum and minimum optical path lengths when perpendicularly crossing surfaces T3 and T4, divided by the distance between surfaces T3 and T4. A second index was also measured, which was the standard deviation of the optical path lengths corresponding to a length of 1 mm when perpendicularly crossing surfaces T3 and T4.

[0138] Tables 1 to 3 show the composition of the raw materials and the measured values ​​of the obtained glasses in each example.

[0139] 11A and 11B are schlieren images of the glass of Example 5 and Comparative Example 1 taken from above, respectively.

[0140] Furthermore, when the physical properties of Examples 1 to 14 were measured, the partial dispersion ratio (P ｇ，Ｆ ) and Abbe number (ν ｄ ) is P ｇ，Ｆ ≦−0.0042×ν ｄ +0.7193 and the wavelength (λ ８０ ) and Abbe number (ν ｄ ) is λ ８０ ≦−10.253×ν ｄ +672.5, and the glass transition temperature T ｇ and the difference ΔT between the crystallization onset temperature and the glass transition temperature ≦230°C.

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147] <Evaluation> From Examples 1 to 11 and Comparative Examples 1 and 2, it was found that by setting the volume of glass raw material U to V mg and the supporting time to 0.02 seconds × V seconds, the first index and the second index had good values. That is, a glass in which the occurrence of striae was suppressed was obtained. When the schlieren image of Example 5 was compared with the schlieren image of Comparative Example 2, a hazy shadow was clearly observed in the schlieren image of Comparative Example 1, confirming the presence of striae. Therefore, it was also confirmed from the schlieren image that a glass in which the occurrence of striae was suppressed was obtained in Example 5.

[0148] Furthermore, from Example 14, favorable results were also obtained with a configuration in which a laser was irradiated as the first electromagnetic wave L1, and then a halogen was irradiated as the second electromagnetic wave L2. In particular, when the laser was irradiated to reduce the volume of the glass to V mm ３ It was confirmed that by irradiating the glass with a halogen heater for 0.02 × V seconds or more as the laser beam and then irradiating the glass with a halogen heater for 10 seconds or more after the laser was stopped, it was possible to obtain glass in which the occurrence of striae was further suppressed even in a glass with a relatively large volume. ２ O, Na ２ O.K. ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ It has been found that when the total content is 10% or less, and in particular when the total content is substantially free of the above, the first index and the second index have good values.

[0149] Although Examples 5 and 6 had the same composition, number of laser irradiation points, whether or not pressing was performed, weight, size, and supporting time, they had different PK-PK and RMS. However, PK-PK and RMS values ​​were obtained within the desired range. In other words, stable performance was confirmed for multiple glasses produced under the same conditions.

[0150] Furthermore, although the trimming range was different between Examples 5 and 6, the desired values ​​for PK-PK and RMS were obtained. In other words, it was found that appropriate evaluation can be performed by using a circular region occupying approximately 50 to 80% of the area from the center as the measurement target region.

[0151] Examples 12 and 13 have the same composition, number of laser irradiation points, presence or absence of pressing, weight, size, and supporting time as Examples 1 and 2. It was found that the first index and the second index also had good values ​​when evaluated by the second measurement method.

[0152] <Optical Elements, Optical Systems, Interchangeable Camera Lenses, Optical Devices, etc.> The optical glass obtained by the manufacturing apparatus 10 according to each embodiment can be suitably used, for example, as an optical element included in an optical instrument. Such optical elements include mirrors, lenses, prisms, filters, etc., and can be widely used as optical systems. The optical systems according to the present embodiments can be suitably used as interchangeable camera lenses including the optical glass. Known configurations can be used for such optical elements, optical lenses, and interchangeable camera lenses. Furthermore, the optical systems according to the present embodiments can be suitably used as optical devices including the optical systems. Optical devices including such optical systems include, but are not limited to, imaging devices such as interchangeable lens cameras and non-interchangeable lens cameras, optical microscopes, and the like. Examples of these devices are described below.

[0153] (Imaging Device) FIG. 12 is a perspective view of an example in which the optical device according to each embodiment is used as an imaging device.

[0154] The imaging device 1 is a so-called digital single-lens reflex camera (interchangeable lens camera), and the photographing lens (optical system) 103 is equipped with the cured product according to this embodiment. A lens barrel 102 is detachably attached to a lens mount (not shown) of a camera body 101. Light passing through a lens 103 of the lens barrel 102 forms an image on a sensor chip (solid-state image sensor) 104 of a multi-chip module 106 arranged on the rear side of the camera body 101. This sensor chip 104 is a bare chip such as a so-called CMOS image sensor, and the multi-chip module 106 is, for example, a COG (chip-on-glass) type module in which the sensor chip 104 is bare-chip mounted on a glass substrate 105.

[0155] FIG. 13 is a front view of another example in which the optical device according to each embodiment is used as an imaging device, and FIG. 14 is a rear view of the imaging device.

[0156] The imaging device CAM is a so-called digital still camera (non-interchangeable lens camera), and the photographing lens (optical system) WL is equipped with the cured product according to this embodiment. When the power button (not shown) of the imaging device CAM is pressed, a shutter (not shown) of the photographing lens WL is opened, and light from a subject (object) is collected by the photographing lens WL and focused on an imaging element disposed on the image plane. The subject image focused on the imaging element is displayed on an LCD monitor M disposed behind the imaging device CAM. After determining the composition of the subject image while looking at the LCD monitor M, the photographer presses the release button B1 to capture the subject image with the imaging element and record and save it in memory (not shown). The imaging device CAM is equipped with an auxiliary light emitter EF that emits auxiliary light when the subject is dark, a function button B2 used to set various conditions for the imaging device CAM, and the like.

[0157] Optical systems used in such digital cameras and the like are required to have higher resolution, lighter weight, and smaller size. To achieve these, it is effective to use optical glass with a high refractive index in the optical system. From this perspective, the optical glass according to each embodiment is suitable as a component of such optical equipment. Note that optical equipment to which each embodiment can be applied is not limited to the imaging device described above, but also includes, for example, projectors, etc. Optical elements are also not limited to lenses, but include, for example, prisms, etc.

[0158] (Multiphoton Microscope) FIG. 15 is a block diagram showing an example in which the optical device according to each embodiment is a multiphoton microscope.

[0159] The multiphoton microscope 2 includes, as optical elements, an objective lens 206, a condenser lens 208, and an imaging lens 210. The following description will focus on the optical system of the multiphoton microscope 2.

[0160] The pulsed laser device 201 emits ultrashort pulsed light, for example, with a near-infrared wavelength (approximately 1000 nm) and a pulse width in femtosecond units (e.g., 100 femtoseconds). The ultrashort pulsed light immediately after being emitted from the pulsed laser device 201 is generally linearly polarized in a predetermined direction.

[0161] The pulse splitting device 202 splits the ultrashort pulsed light, increases the repetition frequency of the ultrashort pulsed light, and emits it.

[0162] The beam adjusting unit 203 has functions such as a function to adjust the beam diameter of the ultrashort pulsed light incident from the pulse splitting device 202 to match the pupil diameter of the objective lens 206, a function to adjust the focusing and divergence angles of the ultrashort pulsed light in order to correct on-axis chromatic aberration (focus difference) between the wavelength of the multiphoton excitation light emitted from the sample S and the wavelength of the ultrashort pulsed light, and a pre-chirp function (group velocity dispersion compensation function) to impart reverse group velocity dispersion to the ultrashort pulsed light in order to correct the pulse width of the ultrashort pulsed light being broadened by group velocity dispersion while passing through the optical system.

[0163] The repetition frequency of the ultrashort pulsed light emitted from the pulsed laser device 201 is increased by the pulse dividing device 202, and the above-mentioned adjustment is performed by the beam adjusting unit 203. The ultrashort pulsed light emitted from the beam adjusting unit 203 is then reflected by the dichroic mirror 204 toward the dichroic mirror 205, passes through the dichroic mirror 205, and is collected by the objective lens 206 to be irradiated onto the sample S. At this time, the ultrashort pulsed light may be scanned over the observation surface of the sample S by using a scanning means (not shown).

[0164] For example, when observing the fluorescence of a sample S, the fluorescent dye with which the sample S is stained undergoes multiphoton excitation in the area of ​​the sample S irradiated with the ultrashort pulsed light and in its vicinity, emitting fluorescence (hereinafter referred to as "observation light") having a wavelength shorter than that of the ultrashort pulsed light, which is an infrared wavelength.

[0165] Observation light emitted from the sample S in the direction of the objective lens 206 is collimated by the objective lens 206 and is reflected by or transmitted through the dichroic mirror 205 depending on its wavelength.

[0166] The observation light reflected by the dichroic mirror 205 enters the fluorescence detection unit 207. The fluorescence detection unit 207 is composed of, for example, a barrier filter, a PMT (photomultiplier tube), etc., receives the observation light reflected by the dichroic mirror 205, and outputs an electrical signal corresponding to the amount of light. Furthermore, the fluorescence detection unit 207 detects the observation light across the observation surface of the sample S as the ultrashort pulsed light scans the observation surface of the sample S.

[0167] On the other hand, the observation light that has passed through the dichroic mirror 205 is descanned by a scanning means (not shown), passes through the dichroic mirror 204, is focused by the focusing lens 208, passes through a pinhole 209 located at a position approximately conjugate to the focal position of the objective lens 206, passes through an imaging lens 210, and enters the fluorescence detection unit 211.

[0168] The fluorescence detection unit 211 is configured with, for example, a barrier filter, a PMT, etc., receives the observation light imaged on the light receiving surface of the fluorescence detection unit 211 by the imaging lens 210, and outputs an electrical signal according to the amount of light. Furthermore, the fluorescence detection unit 211 detects the observation light across the observation surface of the sample S as the ultrashort pulsed light scans the observation surface of the sample S.

[0169] It is also possible to remove the dichroic mirror 205 from the optical path so that all of the observation light emitted from the sample S in the direction of the objective lens 206 is detected by the fluorescence detection unit 211 .

[0170] Furthermore, observation light emitted from the sample S in the direction opposite to the objective lens 206 is reflected by the dichroic mirror 212 and enters the fluorescence detection unit 213. The fluorescence detection unit 213 is composed of, for example, a barrier filter, a PMT, etc., and receives the observation light reflected by the dichroic mirror 212 and outputs an electrical signal according to the amount of light. Furthermore, the fluorescence detection unit 213 detects the observation light across the observation surface of the sample S as the ultrashort pulsed light scans the observation surface of the sample S.

[0171] The electrical signals output from the fluorescence detection units 207, 211, and 213 are input, for example, to a computer (not shown), which can generate an observation image based on the input electrical signals, display the generated observation image, and store the data of the observation image.

[0172] <Cemented Lens> Fig. 16 is a schematic diagram showing an example of a cemented lens according to each embodiment. The cemented lens 3 is a compound lens having a first lens element 301 and a second lens element 302. At least one of the first lens element and the second lens element uses the optical glass according to each embodiment. The first lens element and the second lens element are cemented together via a cementing member 303. A known adhesive or the like can be used as the cementing member 303. Note that the lenses that make up the cemented lens may be referred to as "lens elements" as described above, in order to clearly indicate that they are elements of the cemented lens.

[0173] The cemented lens according to each embodiment is useful from the viewpoint of chromatic aberration correction, and can be suitably used in the optical elements, optical systems, optical devices, etc. described above. Furthermore, optical systems including cemented lenses can be particularly suitably used in interchangeable lenses for cameras, optical devices, etc. While the cemented lens using two lens elements has been described in the above-described embodiments, this is not limiting, and a cemented lens using three or more lens elements may also be used. When a cemented lens using three or more lens elements is used, it is sufficient that at least one of the three or more lens elements is formed using the optical glass according to this embodiment.

[0174] As described above, at least some of the constituent elements of each of the above-described embodiments can be appropriately combined with at least some of the other constituent elements of each of the above-described embodiments. The present invention can be appropriately modified within the scope of the claims and the gist or concept of the invention as can be read from the entire specification, and glass manufacturing methods and glasses incorporating such modifications are also included within the technical scope of the present invention.

[0175] 1...imaging device (interchangeable lens camera), 10...manufacturing device, 11...stage, 12...support member, 13, 23...light source, 14, 15...mirror, 16...radiation thermometer, 17...computer, 18...CCD camera, 19...monitor, 20...gas flow regulator, L1: first electromagnetic wave, L2: second electromagnetic wave, R1, R2: measurement target area, U: glass raw material, T1, T2, T3, T4...surface, V1, V2, V3, V4, V5, V6, V7: laser irradiation position, 101...camera body, 102...lens barrel, 103...lens, 104...sensor chip, 105...glass substrate, 106...multi-chip top module, CAM...imaging device (non-interchangeable lens camera), WL...taking lens, M...liquid crystal monitor, EF...fill-in light emitting unit, B1...release button, B2...function button, 2...multiphoton microscope, 201...pulse laser device, 202...pulse splitter, 203...beam adjusting unit, 204, 205, 212...dichroic mirror, 206...objective lens, 207, 211, 213...fluorescence detecting unit, 208...condensing lens, 209...pinhole, 210...imaging lens, 3...cemented lens, 301...first lens element, 302...second lens element, 303...cementing member

Claims

1. A method for producing glass from glass frits, comprising: heating the frits to form a molten state; supporting the frits in a contactless manner; and irradiating the frits with electromagnetic waves, wherein the irradiating the frits with electromagnetic waves comprises: irradiating the frits in a molten state supported in a contactless manner with a first electromagnetic wave, which is absorbed by the frits with a first absorption coefficient; irradiating the frits in a molten state supported in a contactless manner with a second electromagnetic wave, which is absorbed by the frits with a second absorption coefficient smaller than the first absorption coefficient; and stopping the irradiation of the first electromagnetic wave to the frits after stopping the irradiation of the second electromagnetic wave to the frits.

2. The method for producing glass according to claim 1, wherein the irradiating the second electromagnetic waves includes continuously irradiating the second electromagnetic waves for 10 seconds or more after terminating the irradiation of the first electromagnetic waves.

3. A method for producing glass from glass frits, comprising: heating the frits to form a molten state; supporting the frits in a contactless state; and irradiating the frits with electromagnetic waves, wherein the irradiating the frits with the electromagnetic waves comprises: irradiating the frits in a molten state supported in a contactless state with a first electromagnetic wave that is absorbed by the frit with a first absorption coefficient; irradiating the frits in a molten state supported in a contactless state with a second electromagnetic wave that is absorbed by the frit with a second absorption coefficient that is smaller than the first absorption coefficient; and stopping the irradiation of the second electromagnetic wave to the frit after reducing the irradiation amount of the first electromagnetic wave to the frit.

4. The method for producing glass according to claim 3, wherein the irradiating of the second electromagnetic waves includes continuously irradiating the second electromagnetic waves for 10 seconds or more after reducing the irradiation amount of the first electromagnetic waves.

5. A method for producing glass according to any one of claims 1 to 4, wherein the wavelength of the first electromagnetic wave is 100 nm or more and less than 400 nm, or 5000 nm or more and less than 10 cm.

6. A method for producing glass according to any one of claims 1 to 5, wherein the wavelength of the second electromagnetic wave is 400 nm or more and less than 5000 nm.

7. The irradiation of the first electromagnetic wave reduces the volume of the glass raw material to V mm ３ The method for producing glass according to any one of claims 1 to 6, comprising irradiating the glass raw material with the first electromagnetic wave for 0.02 × V seconds or more continuously.

8. The method for producing glass according to any one of claims 1 to 7, wherein supporting the glass frit in a molten state in a non-contact manner includes providing a gas in a first space between the glass frit and a support member provided below the glass frit.

9. The method for producing glass according to claim 8, wherein supporting the glass raw material in a molten state in a non-contact manner includes supplying the gas to the first space through a supply hole provided in the support member.

10. The method includes placing the glass frit on the supporting member, and supplying the gas to the glass frit placed on the supporting member through the supply holes, wherein the step of bringing the glass frit into a molten state includes heating the glass frit placed on the supporting member, and the step of supporting the glass frit in a molten state without contacting the glass frit includes controlling the volume of the glass frit to V mm ３ 10. The method for producing glass according to claim 9, further comprising supporting the glass frit for a period of 0.02×V seconds or more from the time when the glass frit, at least a part of which has been melted by the heating, starts to float up from the support member by the gas supplied through the supply holes.

11. A method for producing glass according to any one of claims 1 to 10, further comprising irradiating the second electromagnetic wave during the period in which the first electromagnetic wave is irradiated.

12. A method for producing glass according to any one of claims 1 to 11, wherein irradiation with the second electromagnetic wave covers a wider area of ​​the glass raw material surface than irradiation with the first electromagnetic wave.

13. A method for producing glass according to any one of claims 1 to 12, wherein the irradiation of the second electromagnetic wave is carried out so that, in a plan view in the direction of gravity, the area of ​​the irradiated region of the surface of the glass frit in a molten state with the second electromagnetic wave is 10% or more of the total area of ​​the glass frit.

14. A method for producing glass according to any one of claims 1 to 13, wherein the irradiation of the second electromagnetic wave forms an irradiated area on the surface of the glass frit in a molten state, the diameter of which is 30% or more of the diameter of the glass frit in a plan view in the direction of gravity.

15. A method of manufacturing glass for manufacturing glass from glass frits, comprising: heating the glass frits to make them into a molten state; supporting the glass frits in a non-contact state; and irradiating the glass frits with electromagnetic waves, wherein the irradiating of the electromagnetic waves comprises irradiating the glass frits with first electromagnetic waves having a wavelength of 100 nm or more and less than 400 nm or a wavelength of 5000 nm or more and less than 10 cm, and reducing the volume of the glass frits to V mm ３ the glass raw material in the molten state is supported in a non-contact manner and the first electromagnetic wave is irradiated for at least 0.02 × V seconds.

16. A method for producing glass from glass raw materials, comprising: heating the glass raw materials to form a molten state; supporting the glass raw materials in a non-contact state in the molten state; and irradiating the glass raw materials with electromagnetic waves, wherein the irradiating of the electromagnetic waves comprises irradiating the glass raw materials with second electromagnetic waves having a wavelength of 400 nm or more and less than 5000 nm, wherein the steps of supporting the glass raw materials in a molten state in a non-contact state and irradiating the second electromagnetic waves are performed for at least 10 seconds.

17. A method for producing glass according to any one of claims 1 to 16, wherein the temperature of the glass raw material to which the electromagnetic waves are irradiated is equal to or higher than the glass liquidus temperature.

18. A method for producing glass according to any one of claims 1 to 17, wherein the viscosity of the glass raw material to be irradiated with the electromagnetic waves is 0.1 Pa·s or less.

19. A method for producing glass according to any one of claims 1 to 18, wherein the step of bringing the glass into a molten state includes melting the glass raw materials supported in a non-contact manner.

20. A method for producing glass according to any one of claims 1 to 19, comprising, after stopping the irradiation of the electromagnetic waves, lowering the temperature of the glass raw materials to a temperature below the glass transition point.

21. A method for producing glass according to any one of claims 1 to 20, wherein the glass raw material is a pressed body or a sintered body thereof, or an aggregate of crystals.

22. A method for producing glass according to any one of claims 1 to 21, wherein the diameter of the glass obtained by cooling the glass raw material is greater than 10 mm.

23. The glass obtained by cooling the glass raw material contains, in mol%, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ , As ２ O ３ The method for producing glass according to claim 1 , wherein the total content of is 10% or less.

24. A glass manufacturing apparatus for producing glass from glass raw materials, comprising: a heating device for heating the glass raw materials; a support member for supporting the glass raw materials in a molten state without contact; and a cooling device for lowering the temperature of the support member.

25. The glass manufacturing apparatus according to claim 24, wherein the support member has a flow path, and the cooling device passes a refrigerant through the flow path to lower the temperature of the support member.

26. The glass manufacturing apparatus according to claim 24 or 25, comprising: a stage to which the support member is fixed; and a fixing member that contacts the support member and fixes the support member to the stage, the fixing member having a flow path; and the cooling device passing a refrigerant through the flow path to lower the temperature of the fixing member and the support member.

27. The glass manufacturing apparatus according to any one of claims 24 to 26, wherein the heating device includes a first heating device capable of irradiating the glass raw material with a first electromagnetic wave having a wavelength of 100 nm or more and less than 400 nm, or 5000 nm or more and less than 10 cm.

28. The glass manufacturing apparatus according to any one of claims 24 to 27, wherein the heating device includes a second heating device capable of irradiating the glass raw material with a second electromagnetic wave having a wavelength of 400 nm or more and less than 5000 nm.

29. Floating molten glass, wherein the difference between the maximum refractive index and the minimum refractive index in the floating molten glass is 100 x 10 －６ Below is floating molten glass.

30. The float melt glass of claim 29, wherein the standard deviation of the optical path length corresponding to a length of 1 mm in the glass is 15 nm / mm or less.

31. A glass comprising, in mole percent, B ２ O ３ , SiO ２ , P ２ O ５ and As ２ O ３ The total content of (B ２ O ３ +SiO ２ +P ２ O ５ +As ２ O ３ ): 25% or less, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ The total content of (Li ２ O+K ２ O + Na ２ O+P ２ O ５ +B ２ O ３ +WO ３ +As ２ O ３ ): 10% or less, La ２ O ３ , BaO, CaO, MgO, Y ２ O ３ , Gd ２ O ３ , Al ２ O ３ , TiO ２ , Nb ２ O ５ , ZrO ２ and Ta ２ O ５ Total content (La ２ O ３ +BaO+CaO+MgO+Y ２ O ３ +Gd ２ O ３ +Al ２ O ３ + TiO ２ +Nb ２ O ５ + ZrO ２ +Ta ２ O ５ ): 70% or more, and a first index, which is a difference between the maximum and minimum values ​​of an optical path length corresponding to a length of 1 mm in the glass, is 100 nm or less.

32. The glass according to claim 31, wherein the first index is calculated as the difference between the maximum and minimum values ​​of the optical path length when traversing the interior of the glass in a first direction, divided by the length in the first direction.

33. The glass according to claim 31, wherein the first index is calculated by processing the glass so that two opposing surfaces are parallel, and dividing the difference between the maximum and minimum values ​​of the optical path length when traversing the interior of the glass perpendicularly to the two opposing surfaces by the distance between the two opposing surfaces.

34. The glass according to claim 33, wherein the first index is calculated by dividing the difference between the maximum and minimum values ​​of the optical path length when traversing the interior of the glass perpendicular to the two opposing surfaces within a circular region that occupies 50% or more of the area from the center when the glass is viewed in a direction perpendicular to the two opposing surfaces by the distance between the two opposing surfaces.

35. Partial dispersion ratio (P ｇ，Ｆ ) and Abbe number (ν ｄ ) is P ｇ，Ｆ ≦−0.0042×ν ｄ +0.7193 and the wavelength (λ ８０ ) and Abbe number (ν ｄ ) is λ ８０ ≦−10.253×ν ｄ +672.5, and the glass transition temperature T ｇ ≥ 780°C, and a difference ΔT between the crystallization onset temperature and the glass transition temperature ≤ 230°C.

36. A glass comprising, in mole percent, B ２ O ３ , SiO ２ , P ２ O ５ and As ２ O ３ The total content of (B ２ O ３ +SiO ２ +P ２ O ５ +As ２ O ３ ): 25% or less, Li ２ O.K. ２ O, Na ２ O, P ２ O ５ , B ２ O ３ , W.O. ３ and As ２ O ３ The total content of (Li ２ O+K ２ O + Na ２ O+P ２ O ５ +B ２ O ３ +WO ３ +As ２ O ３ ): 10% or less, La ２ O ３ , BaO, CaO, MgO, Y ２ O ３ , Gd ２ O ３ , Al ２ O ３ , TiO ２ , Nb ２ O ５ , ZrO ２ and Ta ２ O ５ Total content (La ２ O ３ +BaO+CaO+MgO+Y ２ O ３ +Gd ２ O ３ +Al ２ O ３ + TiO ２ +Nb ２ O ５ + ZrO ２ +Ta ２ O ５ ): 70% or more, and the difference between the maximum refractive index and the minimum refractive index in the glass is 100 × 10 －６ Below is the glass.

37. The glass of claim 36, wherein the standard deviation of the optical path length corresponding to a length of 1 mm in the glass is 15 nm / mm or less.

38. Glass having a partial dispersion ratio (P ｇ，Ｆ ) and Abbe number (ν ｄ ) is P ｇ，Ｆ ≦−0.0042×ν ｄ +0.7193 and the wavelength (λ ８０ ) and Abbe number (ν ｄ ) is λ ８０ ≦−10.253×ν ｄ +672.5, and the glass transition temperature T ｇ ≥ 780°C, the difference ΔT between the crystallization onset temperature and the glass transition temperature is ≤ 230°C, and the difference between the maximum and minimum refractive indices in the glass is 100 × 10 －６ Below is the glass.

39. The glass of claim 38, wherein the standard deviation of the optical path length corresponding to a length of 1 mm in the glass is 15 nm / mm or less.

40. The glass according to any one of claims 31 to 39, wherein the length of the glass in the major axis direction is 4 mm or more.

41. The glass according to any one of claims 31 to 40, wherein the weight of the glass is 400 mg or more and 10,000 mg or less.

42. The glass according to any one of claims 31 to 41, wherein the glass is substantially free of boron (B).

43. The glass of any one of claims 31 to 42, which is an optical glass.

44. An optical element comprising the glass of any one of claims 31 to 43.

45. An optical system comprising the optical element of claim 44.

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