JPH11100215A - Production of optical glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing many kinds of optical glasses by using a common process via a porous body. SOLUTION: Optical glass having optical filter function and optical glass having no optical filter function are produced with the utilization of the common production process by heating a porous body containing at least one kind of a component decomposable by heat treating to produce a calcined porous body having the component fixed in the porous body and further introducing at least one kind of a component in the calcined porous body and firing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an optical glass and an optical filter through a porous body.
In particular, the present invention relates to a method for producing an optical glass, a gradient index optical glass, and an optical filter via a porous body produced by a sol-gel method.

[0002]

2. Description of the Related Art A method for producing glass by firing a porous body is known. In the method for producing glass via a porous body, since any component can be introduced into the porous body, by changing the concentration of the component to be introduced at a predetermined rate, the glass has a refractive index distribution. Glass for a gradient index optical element can be manufactured. For example, Japanese Patent Publication No. Sho 60-6295 discloses that a part of a stuffing agent filled in a connecting hole forming a porous glass body is dissolved and removed in a solvent, and then the stuffing agent in the connecting hole is thermally decomposed and fixed. A method for producing a glass body by melting is described, and the porous body was obtained by eluting a specific phase of the phase-separated glass with an acid.

On the other hand, there is known a method for producing glass by a sol-gel method in which a glass is produced by firing a porous body obtained by gelling a sol without using a melting method. Various components such as a component for controlling the transmittance, a component for controlling the transmittance, a component for controlling the thermal expansion, a component for controlling the glass transition point, a component for controlling the mechanical properties, and a component for improving the chemical properties. After being introduced, it is baked and vitrified.

[0004] In an optical apparatus, an optical filter is provided in a lens system, and light having a predetermined wavelength is incident on the photosensitive material or the image sensor in accordance with the characteristics of a light source, a photosensitive material, and an image sensor. I am trying to be. For example, in a lens system that forms an image on an electronic imaging device used in a video camera, a digital camera, or the like, an infrared cut filter is generally arranged in front of the imaging device, and light in a near-infrared wavelength range is emitted. Except for this, the sensitivity of the image sensor is corrected so as to be equivalent to the relative luminous efficiency of a person.

The present applicant has disclosed an optical element in which an optical filter and a gradient index optical element are integrated with each other in Japanese Patent Application Laid-Open No. 9-12731.
Proposed as No. 1. If an optical filter function is given to a glass body having such a refractive index distribution, the optical system can be downsized.

Further, it is necessary to introduce various components into the gradient index optical element depending on the purpose. In the conventional method, it is necessary to introduce components necessary for preparing a sol according to each purpose. In order to manufacture a gradient index optical element having a composition of another type, it is necessary to separately perform the steps from preparation of a sol to introduction of necessary components according to each gradient index optical element. In addition, even when some components are slightly different, it is necessary to perform sol preparation to gelation for each refractive index distribution type optical element.

In the production of an optical filter by the sol-gel method, it is necessary to prepare a sol for each purpose to produce a gel, and to introduce necessary components. In the case of a refractive index distribution type optical element having a function, a sol used for manufacturing an optical element having an optical filter function is prepared separately from an optical filter having no optical filter function.

As described above, in the production of the conventional gradient index optical element and the filter, there has been a problem that various types of production steps are required in accordance with the respective characteristics.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently producing other types of gradient index optical elements with a relatively simple process at a stable quality. Another object of the present invention is to provide a method for producing glass having a filter function or a gradient index optical element with stable quality, and to provide a method for producing optical glass easily and at low cost. The task is to do so.

[0010]

According to the present invention, in a method for producing an optical glass, a porous body containing at least one component decomposed by heat treatment is subjected to heat treatment, and the component is fixed in the porous body. After manufacturing the calcined porous body,
Further, this is a method for producing an optical glass in which at least one component is introduced into a calcined porous body and fired.

[0011] In the above method for producing an optical glass, the component to be introduced into the calcined porous body imparts at least one of optical properties, chemical properties, and mechanical properties of the glass.

In the above method for producing an optical glass, the component introduced into the calcined porous body is a component absorbing a specific wavelength, and the optical glass has an optical filter function.

[0013] In the above method for producing an optical glass, an optical filter is produced by introducing a component absorbing a specific wavelength into a calcined porous body.

In the above method for producing an optical glass, the component introduced into the calcined porous body is a component for modifying the properties of the optical glass.

In the above-mentioned method for producing an optical glass, the component contained in the porous body or the component to be introduced into the calcined porous body is a substance exhibiting an infrared absorbing effect on the optical glass.

The substance exhibiting an infrared absorbing effect is copper,
This is the method for producing an optical glass described above, which is at least one substance selected from substances containing iron, cobalt, and vanadium.

The above method for producing an optical glass, which is a refractive index distribution glass having an optical filter function, produced by introducing a component for imparting a refractive index distribution and a component for absorbing a specific wavelength.

After imparting a refractive index distribution by imparting a concentration distribution to the components contained in the porous body, a calcined porous body is produced, and an infrared absorbing effect is exhibited in the calcined porous body. This is a method for producing the optical glass described above, in which a substance is introduced.

Further, there is provided the above method for producing an optical glass, wherein the porous body is produced by a sol-gel method.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an optical glass or filter having a refractive index distribution using a porous body containing at least one element contributing to glass properties. The porous body containing the compound of the above is heated to a temperature at which part or all of the first compound is fixed by thermal decomposition to produce a calcined porous body. A part or the whole is doped with the second element. In general, a glass having a distribution of the refractive index gives a concentration distribution to a component contributing to the refractive index in the glass to form a distribution in the refractive index.

Therefore, it is essential that the refractive index distribution type glass contains at least one kind of refractive index adjusting component which contributes to the refractive index in addition to the substance forming the glass skeleton. In a glass body having a distribution of refractive index, it is sufficient that the glass body contains at least one component that provides a refractive index distribution.
With one type of refractive index adjusting component, the dispersion component of a glass body having a distribution of refractive index has high dispersion distribution characteristics. Since the occurrence of chromatic aberration increases, the use is limited.

Further, in the case of the concave distribution, the chromatic aberration generated in the surface of the glass body and the chromatic aberration generated in the medium cancel each other, so that the chromatic aberration is smaller than that in the case of the convex distribution.

Therefore, in order to obtain a glass body having a distribution of refractive indices having excellent characteristics, it is necessary to include at least two kinds of refractive index adjusting components to correct chromatic aberration in a medium. It is desirable to use a glass body having a distribution with a refractive index having a chromatic aberration correcting ability called a distribution and a negative dispersion distribution. In order to realize a glass body having a refractive index distribution having such characteristics, as described in JP-A-3-151302 and JP-A-5-88003, the valence is divalent. It is desirable to give a concentration distribution to the plurality of components described above to composite the distribution. By the concentration distribution of these plural components, it is possible to manufacture a glass body having a distribution of refractive index having various optical characteristics. In particular, high performance using a glass body with a distribution of refractive index,
In the case of forming optical systems having various characteristics, it is essential that the glass body having a distribution of refractive index has characteristics called low dispersion distribution and negative dispersion distribution.

According to the present invention, it is possible to provide a method of manufacturing such a glass body having a distribution of refractive index having various characteristics by using a common material as much as possible.

For example, a concentration distribution of the first component is imparted to a porous body having a silica component in a skeleton. Next, the porous body is heat-treated to a temperature at which at least a part of the first component is fixed by thermal decomposition. Part or all of the concentration distribution of the first component is fixed. Next, 1) as it is, firing without any special treatment to obtain a dense glass.

2) The component for adjusting the transmittance is brought into contact with the porous body.

For example, the porous body is immersed in a solution containing a copper component and reacted to be fixed on the calcined porous body or, if necessary, immersed again in a solution having a low solubility of the copper compound.
When copper is fixed in a calcined porous body, dried, and then baked to obtain a dense glass with adjusted transmittance, infrared rays can be absorbed. If titanium or cerium is used instead of copper, a glass that absorbs ultraviolet light can be manufactured. It is possible to dope both to absorb both infrared and ultraviolet, or to dope various types of metals to absorb or transmit only light in a specific wavelength range.

3) The porous body is brought into contact with a component for adjusting the refractive index.

For example, the porous body is immersed in a solution containing lead, reacted, and fixed to the calcined porous body. In addition, if necessary, the lead compound is immersed again in a low-solubility solution of the lead compound, and the lead is fixed to the calcined porous body, dried, and fired to adjust the refractive index, or the doped lead is eluted again. Fixed later,
After drying, firing is performed to obtain a dense glass in which the refractive index of the substrate is adjusted.

4) The porous body is brought into contact with the component for adjusting the dispersion.

For example, the porous body is immersed in a solution containing titanium and reacted to fix it on the calcined porous body, or, if necessary, is immersed again in a solution having a low solubility of the titanium compound to reduce the titanium. The glass is fixed in a calcined porous body, dried, and fired to obtain a dense glass in which the distribution of dispersion is adjusted.

5) A porous body is brought into contact with a component for adjusting chemical properties of alkali resistance.

For example, the porous body is immersed in a solution containing zirconium and allowed to react to be fixed on the calcined porous body, or, if necessary, is immersed again in a solution having a low solubility of the zirconium compound to reduce the zirconium. It is fixed in a calcined porous body, dried and fired to obtain a dense glass with adjusted alkali resistance. Water resistance can be improved by introducing alumina, and chemical resistance such as alkali resistance can be improved by introducing zirconia.

6) The porous body is brought into contact with a component for adjusting a mechanical property, for example, a coefficient of thermal expansion. The porous body is immersed in a solution containing an alkali metal such as potassium and reacted to be fixed on the calcined porous body, or, if necessary, immersed again in a solution having a low solubility of the alkali metal compound to form the alkali metal. Is fixed in a calcined porous body, or the doped alkali metal is fixed again after elution, dried, and fired to obtain a dense glass having a controlled thermal expansion coefficient.

7) A substance capable of adjusting the temperature characteristics of the porous body is added.

Since an alkali element, boron oxide and phosphorus oxide can soften the calcined gel at a low temperature, they may be added to facilitate the vitrification of the calcined gel.

As a method for bringing these metal components into contact with the porous body, most commonly, a method of immersing the porous body in a solution containing components for adjusting various properties, or a method of contacting the porous body A method of eluting or exchanging a compound of the first element which has not been partially decomposed therein can be used.

It is also possible to introduce the liquid by contact with a liquid in the form of a mist, a foam, or a shower, or a gas phase containing the component to be introduced. At that time, a concentration distribution may be imparted to the characteristic adjustment component, or a uniform distribution may be introduced, depending on the processing time, concentration, selection of a solvent, setting of post-processing conditions, and the like.

The order of introduction may be determined according to the properties of the compound to be introduced and the like. For example, when producing an optical glass containing both a substance giving a refractive index distribution and a substance absorbing a specific wavelength. , Any of the substances may be introduced first.

According to the method of the present invention, various types of gradient index glass can be manufactured by a common process halfway. Can be obtained, and the transmittance can be arbitrarily adjusted.

Hereinafter, the production of an optical element that can be produced by using the calcined porous body by the method of the present invention will be described.

(1) Optical Element with Adjusted Transmittance It can be applied to the manufacture of an optical element that absorbs light in a specific wavelength range.

In order to impart infrared cut characteristics to the gradient index glass, CuO, FeO, CoO, VO ₂
It is good to contain the metal oxide of. This is because these elements have relatively low absorption in the visible region and sufficient absorption in the infrared region.

In the case of iron oxide, the effect cannot be obtained unless it is divalent iron. When trivalent iron coexists, Fe ²⁺ + -OF
Absorption appears in the visible part due to the ³⁺ bond. To prevent this,
FeF ₆ ^3- and FePO ₄ it is sufficient to the formation.

In the case of copper oxide, when monovalent copper coexists, C
u ² + -O-Cu ⁺ becomes a chromophore. Also, O ₂ to be coordinated to the divalent copper ^- if decreases, the color tone from blue to green, varying black. To prevent this, F and P may be doped.

Since the doping amount of CuO, FeO, CoO, and VO ₂ is often small, the influence on the refractive index distribution and the like can be substantially ignored. In particular, when a component for transmittance adjustment is uniformly doped, the refractive index distribution shape hardly changes, and only the refractive index and dispersion change. Therefore, it is possible to obtain an optical element in which the refractive index and the dispersion are moved in parallel while the refractive index distribution shape is maintained.

Further, there is an increasing demand for an electronic image pickup optical system using an image pickup device such as a CCD. Since the CCD also has sensitivity in the infrared region, an infrared cut filter is required. If an infrared cut function is provided in the refractive index distribution type lens, an ultra-compact optical system can be realized. The component that cuts infrared rays also cuts light in the visible range to some extent, so that coloring occurs. For this reason, it cannot be used in an ordinary optical system, and a colorless gradient index lens is required. A refractive index distribution type lens having the same refractive index distribution necessary for use in an ordinary optical system and different in only transmittance can be manufactured in a common step by the following procedure. With this method, the in-process period can be shortened.

Gel having a composition distribution (colorless) → calcination until the temperature at which some or all of the metal components decompose → calcination as it is → colorless refractive index distribution type glass → immersion in copper-containing solution → calcination → infrared cut refraction (2) Optical element with modified concentration distribution As described below, in the process of manufacturing the refractive index distribution type optical element by impregnating a component for imparting the refractive index distribution to the calcined porous body, a part thereof is produced. After imparting a concentration distribution to the porous body, the optical characteristics are measured, and based on the result, the concentration distribution of the component introduced into the porous body can be corrected to obtain an optical element having a desired concentration distribution.

Gel having a composition distribution → calcining to a temperature at which part or all of the metal component decomposes → partially sintering and vitrification → measurement of optical properties → porous calcined based on the measurement results of optical properties Correcting the concentration distribution of the body → refractive index distribution type glass having predetermined optical characteristics (3) Addition of characteristics other than the optical characteristics The required characteristics of the optical element differ depending on the application to be used. Endoscopes need to be sterilized in high-temperature, high-pressure steam.In addition, endoscopes used for industrial purposes may be used in a high-temperature environment, such as when observing the combustion process. For endoscopes, glass that is highly resistant to high-temperature environments is required.

On the other hand, it is not necessary to use an optical system which is used in an optical system in a normal use environment, with a particularly improved resistance.

Therefore, as described below, a calcined porous body that can be used in common to both can be manufactured, and a glass can be manufactured by introducing a component that improves properties such as heat resistance. Components that can be introduced into the calcined porous body for such a purpose include Al, Ti, Zr, etc., but Al, which has little influence on optical characteristics, is preferable.

Gel having composition distribution → a part of metal component,
Or calcination until the temperature at which all of them are decomposed → immersion in a metal component-containing solution for improving resistance, etc. → calcination and vitrification
A sol-gel method, a method using a porous glass produced by separating phases of molten glass, and a soot produced by CVD can be used.

In particular, in the case of the production by the sol-gel method, a liquid sol is prepared from a liquid raw material, poured into a gel molding container, and left to stand for a certain period to be gelled to produce a jelly-like gel. Subsequently, the gel is dried to form a dry gel which is a porous body, and finally calcined to obtain a glass body.

In the production of an optical element by the sol-gel method, a substance for adjusting the properties of glass is added to a sol, and a substance for adjusting the properties of glass is added to a porous material such as a wet gel or a dry gel or a calcined porous material. Any method such as introduction can be used. In addition to the introduction of the components into the gel, a treatment such as forming a concentration distribution by eluting the components introduced in advance in the sol forming step or the like into the immersion liquid may be performed. The gel may be dried to obtain a dry gel which is a porous body after immersion treatment in an appropriate solution so as not to be disturbed, and finally baked to obtain a dense refractive index distribution type glass. Further, in the method of the present invention, since various components can be doped in various steps as described above,
The composition has a high degree of freedom, and the sol-gel method is particularly suitable.

[0055]

The present invention will be described below with reference to examples.

Example 1 50 ml of tetramethoxysilane and 50 ml of tetraethoxysilane were mixed, and 1/100 N hydrochloric acid 42 was added thereto.
Then, the mixture was stirred at room temperature for 1 hour to perform partial hydrolysis. To this solution was added a 1.25 mol / l aqueous solution of lead acetate 1
A solution obtained by mixing 80 ml and 26 ml of acetic acid was added, and 1
The mixture was stirred for 0 minutes to prepare a sol. The inner diameter of this sol is 50 mm
And gelled.

The obtained gel was brought into contact with a 0.61 mol / l lead acetate solution dissolved at 60 ° C. in a mixed solvent of isopropanol: water = 8: 2 (volume ratio, hereinafter, liquid ratio is referred to as volume ratio). Acetic acid was removed and the gel was aged.
This gel was treated with isopropanol, 2-propanol: acetone = 8: 2, 2-propanol: acetone = 5: 5,
By immersing the gel in the order of acetone for 24 hours each, microcrystals of lead acetate were precipitated and fixed in the gel pores.
The obtained homogeneous gel was immersed in 350 ml of a 0.3 mol / l methanol solution of potassium acetate for 8.5 hours to give a concentration distribution, and then 2-propanol, 2-propanol: acetone = 8: 2, 5: 5. By immersing in acetone in this order, microcrystals of lead acetate and potassium acetate were precipitated and fixed in the pores of the gel.

After drying the gel, it was calcined to 430 ° C. under flowing oxygen, cooled to room temperature, immersed in a 2-propanol solution of Al (OsecC ₄ H ₉ ) ₃ , dried, and dried
When baked to ℃, a glass body having a diameter of about 20 mm and a distribution of refractive index was obtained. This glass had better water resistance than the one not doped with aluminum.

[0059] Also, in the same manner using _{Al (NO 3) 3 · 9H} 2 O in methanol instead of 2-propanol solution of _{Al (OsecC 4 H 9) 3} , can be doped with aluminum Yes, water resistance was improved.

Example 2 25 ml of 0.01 N hydrochloric acid was added to 50 ml of tetramethyl silicate and stirred for 1 hour to carry out a partial hydrolysis reaction. Here, a 1.5 mol / l barium acetate aqueous solution 9
A mixture of 8 ml and 40 ml of acetic acid was added. The mixture was further stirred for 30 minutes, then poured into a fluororesin container having an inner diameter of 10 mm and provided with a hole having a high roundness, the container was closed with a lid, and gelled at room temperature. The obtained gel was aged for 5 days, and then 0.45 m of barium acetate at 60 ° C. using a mixed solvent of 2-propanol: water = 6: 4.
immersion in an ol / l solution to remove acetic acid. By immersing the obtained gel in a mixed solvent of methanol and ethanol and ethanol, barium acetate microcrystals were precipitated and fixed in the gel pores.

The obtained homogeneous gel was immersed in 150 ml of a 0.3 mol / l methanol solution of potassium acetate for 8.5 hours to give a concentration distribution, and then ethanol: acetone =
By immersing in 5: 5 and acetone in this order, barium acetate and potassium acetate microcrystals were precipitated and fixed in the gel pores.

The gel was gradually heated from 60 ° C. to 100 ° C., dried, calcined to 450 ° C. in an oxygen stream, and then cooled to room temperature.

A portion of the calcined gel was immersed in a 0.1 M ethanol solution of copper acetate and then dried, followed by flowing oxygen to 600 ° C., and forming a dense glass body up to 700 ° C. under helium ventilation. This glass body had a refractive index distribution of Δn ≒ 0.04 and an infrared cut function. Visible ~
When the spectral transmittance in the infrared region was measured, it was found that 800 nm
The transmittance in the long wavelength range (near-infrared range) was low from the vicinity, and the transmittance was high without any problem in the visible range.

On the other hand, the calcined porous body was fired under oxygen ventilation up to 600 ° C. and under helium ventilation up to 700 ° C. to obtain a dense glass body. This glass body had a refractive index distribution of Δn ≒ 0.04 without an infrared cut function.

The refractive index distributions of these two types of glass bodies were equivalent.

Example 3 A gel prepared in the same manner as in Example 1 was treated in the same manner as in Example 1 to produce a calcined porous body. After cooling the calcined porous body to room temperature, a part of the calcined porous body was 0.61 mol / using a mixed solvent of 2-propanol: water = 8: 2.
Lead acetate solution, 2-propanol, 2-propanol:
Acetone = 8: 2, 5: 5, and the gel is immersed in acetone for 24 hours each to precipitate and fix the fine crystals of lead acetate uniformly in the pores of the calcined porous body, and then dry. 5
When calcined to 25 ° C., a glass body having a refractive index distribution shown in FIG. 1 and having a diameter of 20 mm was obtained.

A part of the calcined porous body was fired up to 450 ° C. under oxygen ventilation, and fired up to 540 ° C. under helium ventilation to obtain a dense glass body. A glass body having a refractive index distribution having a diameter of 20 mm and having a refractive index distribution shown in FIG. 2 was obtained.

As described above, by adjusting the concentration of the lead solution in which the calcined porous body is immersed, glass bodies having different refractive index distributions can be manufactured.

Example 4 A gel prepared in the same manner as in Example 1 was treated in the same manner as in Example 1 to produce a calcined porous body. After cooling the calcined porous body to room temperature, a part of the calcined porous body was 0.61 mol / using a mixed solvent of 2-propanol: water = 8: 2.
Lead acetate solution, 2-propanol, 2-propanol:
Acetone = 8: 2, 5: 5, and the gel were contacted with acetone for 24 hours each to uniformly precipitate and fix lead acetate microcrystals in the gel pores of the calcined porous body. After this,
Further, after immersing in 350 ml of 0.3 mol / l methanol solution of potassium acetate for 8.5 hours to give a concentration distribution, 2-propanol, 2-propanol: acetone =
By immersing 8: 2, 5: 5 and acetone in this order,
Microcrystals of lead acetate and potassium acetate were precipitated and fixed in the pores of the calcined porous body.

Next, in order to correct the distribution of the coefficient of thermal expansion, the calcined product was again calcined to 450 ° C. in an oxygen atmosphere, cooled at room temperature, and cooled with a 0.3 ml
After being immersed for 15 minutes in a ml, dried, baked and vitrified, a glass body having a distribution in refractive index without cracking was obtained.

On the other hand, except that the calcined porous body was not immersed in a potassium acetate solution, it was broken during cooling when dried, fired, and vitrified. This is presumably because the lead concentration distribution is large and therefore has a distribution in the thermal expansion coefficient.

Example 5 A calcined porous body was produced in the same manner as in Example 2. A part of the calcined gel was immersed in a 0.1 M Ti (OnC ₄ H ₇ ) ₄ ethanol solution, dried, heated to 600 ° C. under oxygen aeration, and helium aerated to 700 ° C. And a fine glass body. This glass body had optical characteristics having a refractive index and a dispersion distribution as shown by a solid oblique line in FIG.

The remaining part of the calcined gel was calcined as it was, calcined up to 600 ° C. under oxygen ventilation, and calcined up to 700 ° C. under helium ventilation to obtain a dense glass body. This glass body had optical characteristics having a refractive index and a dispersion distribution as shown by a solid oblique line in FIG.

As described above, the optical properties, particularly the dispersion properties, are controlled by the concentration of the titanium component-containing solution in which the calcined gel is immersed, and the glass body having a refractive index distribution having various optical properties. Can be manufactured.

Example 6 Silicon tetramethoxide (Si (OCH ₃ ) ₄ ) 4
9.5 g and 90 g of normal propanol are mixed,
Next, 6.0 g of 1/100 N hydrochloric acid was added, and the mixture was stirred for 60 minutes, partially hydrolyzed, and then 25.6 g of titanium tetranormal butoxide (Ti (OnC ₄ H ₉ ) ₄ ) was added. Stirred. Then lanthanum acetate
200 ml of 1N-hydrochloric acid in which 65.5 g of pentahydrate was dissolved was added, and the mixture was stirred and poured into a cylindrical container made of a fluororesin to form a gel, thereby obtaining a wet gel. This wet gel was aged at 60 ° C. for 7 days, and methanol / potassium acetate-containing methanol /
The lanthanum was immersed in an ethanol mixed solution to give a concentration distribution. Thereafter, the mixture was successively immersed in an acetone / 2-propanol mixed solution containing acetic acid and acetone for 24 hours.
After drying to 00 ° C., firing was performed under oxygen aeration to 600 ° C. to produce a calcined porous body.

The obtained calcined porous material was treated with 0.1 M aluminum triSEC-butoxide (Al (OsecC ₄ H ₉ ) ₃ ).
After immersion in an ethanol solution of the above, the resultant was dried and fired under oxygen ventilation to 600 ° C., and fired under helium ventilation until 950 ° C. to produce a glass body having a dense refractive index distribution.

Comparative Example 2 A calcined porous body was produced in the same manner as in Example 6, and calcined without doping with aluminum. As a result, it was crystallized and glass could not be produced.

Example 7 In the same manner as in Example 2, a calcined porous body was produced. Three of the resulting calcined porous bodies were fired up to 600 ° C. under oxygen ventilation, and fired up to 700 ° C. under helium ventilation to obtain a dense glass body. When the refractive index distribution of this glass body was measured, the distribution shape was out of the tolerance range because the refractive index of the peripheral portion was slightly high. Then, a part of the remaining calcined gel was exposed to the vapor of boron trimethoxide (B (OCH ₃ ) ₃ ), and only the periphery was doped with boron. The calcined porous body subjected to this treatment was fired up to 600 ° C. under oxygen ventilation, and fired up to 700 ° C. under helium ventilation to obtain a dense glass body. When the refractive index distribution of this glass body was measured, the distribution shape was within the tolerance range. Example 8 A calcined gel was produced in the same manner as in Example 2. Three of the calcined porous bodies were fired to 600 ° C. under oxygen ventilation,
Sintering was performed under helium aeration up to 00 ° C. to obtain a dense glass body. When the refractive index distribution of this glass body was measured, the distribution shape was out of the tolerance range because the refractive index of the peripheral portion was slightly low. Therefore, the remaining calcined porous body is reduced to 0.0
It was immersed in a 5M methanol solution of barium acetate for 20 minutes, and only the periphery was doped with barium. Thereafter, barium was fixed by immersion in acetone and dried. The calcined porous body subjected to this treatment was fired up to 600 ° C under oxygen ventilation, and fired up to 700 ° C under helium ventilation to obtain a dense glass body. When the refractive index distribution of the obtained glass body was measured, the distribution shape was within the tolerance range, and a refractive index distribution type glass having a desired refractive index distribution could be obtained.

[0079]

According to the present invention, in a method for manufacturing a glass body via a porous body, a calcined porous body in which some components are fixed by heat treatment is manufactured, and then a component according to the purpose is manufactured. By the introduction, other types of glass bodies can be manufactured, the manufacturing process can be simplified, the concentration distribution in the porous body can be easily adjusted, and the refractive index distribution can be improved. , A glass, a filter and the like having the above can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a refractive index distribution of a gradient index glass manufactured by a method of the present invention.

FIG. 2 is a diagram illustrating a refractive index distribution of a gradient index glass manufactured by the method of the present invention.

FIG. 3 is a diagram illustrating optical characteristics of a gradient index glass manufactured by the method of the present invention.

FIG. 4 is a diagram illustrating optical characteristics of a gradient index glass manufactured by the method of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02B 5/20 G02B 5/22 5/22 1/10 Z

Claims (2)

[Claims] In a method for producing an optical glass, a porous body containing at least one component decomposed by heat treatment is subjected to a heat treatment to produce a calcined porous body in which the component is fixed in the porous body. A method for producing an optical glass, characterized in that at least one kind of component is further introduced into the calcined porous body and then calcined. 2. A refractive index distribution glass having an optical filter function, manufactured by introducing a component for imparting a refractive index distribution and a component for absorbing a specific wavelength. Of producing optical glass.