JPS63206318A - Production of glass body for optical transmission - Google Patents

Abstract

PURPOSE:To enable ready formation of a glass body for optical transmission having a constant dopant concentration gradient, by dipping porous glass homogeneously soaked with the dopant in hot water, taking out the porous glass, drying the porous glass at a specific temperature or above and sintering the dried porous glass. CONSTITUTION:A dopant is diffused into porous glass and the resultant sample is placed in a solvent to produce distribution in the dopant concentration. The dopant concentration is then fixed and the sample is subsequently passed through drying and sintering to provide a glass body having refractive index distribution which is a glass body for optical transmission. In the process for producing the glass body, the following method is used. That is distribution is formed in the sample homogeneously soaked with the dopant in hot water and the sample is directly dried at >=150 deg.C temperature in producing distribution of dopant concentration and fixing the distribution thereof.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a glass body for light transmission.

[Prior Art] A molecular stuffing method is known as a method for manufacturing a glass body having a refractive index gradient. This method works inside a porous glass body! : A method in which a dopant is filled into the pores of a porous glass body so that a concentration gradient of a band (refractive index modifying component) is formed, and then the pores are crushed by heat treatment (firing). Japanese Patent Publication No. 51-12607' discloses that after a dopant solution is infiltrated into a porous glass body, a part of the dopant is eluted from the glass body to form a concentration gradient in the dopant distributed in the pores, and then A method for producing a glass body with a refractive index gradient is taught, which comprises precipitating a dopant into the pores, drying the glass body, and then subjecting it to a firing treatment to collapse the pores.

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, at the time of filling a porous glass body with a dopant, eluting the dopant solution to form a dopant concentration gradient, and then drying - A phenomenon occurs in which the concentration of supported particles is averaged, making it difficult to obtain a glass body having a desired refractive index distribution.The present invention is intended to solve these problems, and its purpose is to: An object of the present invention is to easily manufacture a glass body for light transmission having a constant concentration gradient.

Means for Solving Problem E] The method for producing a glass body for optical transmission of the present invention is to diffuse a dopant into a porous glass, then place a sample in a solvent to create a uniform distribution of dopant concentration. dopant'a
The concentration distribution of the dopant in the manufacturing method of a glass body for optical transmission, in which the refractive index distribution is fixed and the refractive index distribution glass body is obtained through drying and sintering. 1 immediately after generating the distribution in
Drying at a temperature of 50°C or higher is the @ sign.

[Function] After sufficiently diffusing the dopant into the porous glass body,
In order to distribute the concentration of Dopan I, the porous glass is immersed in a solvent such as a mixture of alcohol and water to dissolve the dopant. At this point, the primary sample, in which the concentration of dopant is graded from near the surface to the interior, is dried and sintered into a transparent glass body.

However, during this drying process, the solvent in the sample moves from near the center toward the periphery, and the dopants in the sample also move accordingly, resulting in a glass with a relaxed concentration distribution. As in the invention, if a sample uniformly impregnated with dopant is distributed in hot water,
After removing the sample from hot water, the water near the surface of the sample evaporates naturally. Therefore, since the solvent is present only near the center, there is less possibility that the dopant will dissolve in the solvent and move. Further, after this, the solvent starts to move toward the surroundings, but by drying at a high temperature of 150° C. or higher before this movement, the solvent can be removed without moving the dopant. As a result, a porous glass body having a clear concentration gradient can be obtained, and by sintering this, a glass body for light transmission can be obtained.

[Example] The present invention will be described in detail below based on examples.

Example-1 Ethyl millicate (S i (OC2H5) 4
) 1 mol of water and 8.7 mol of water, IN hydrochloric acid was added and stirred vigorously to perform hydrolysis.
5i02 fine particles were added and ultrasonic irradiation was performed to obtain a highly homogeneous sol. When this sol was poured into a tube with an inner diameter of 10°+mΦ and kept at 30°C, it solidified after 3 days.

Thereafter, it was dried at 60°C for 5 days and sintered to 1050°C under a certain program to obtain a porous glass with an outer diameter of 61Φ. This porous glass has pores that account for 17% of the total volume.

This porous glass was held in a saturated aqueous solution of cesium nitrate at 80° C. for several hours to sufficiently diffuse cesium nitrate within the pores. After this, the sample was immersed in hot water at 95°C for 5 minutes.

After 5 minutes, the sample was removed from the hot water and rapidly dried in an oven at 300°C. Thereafter, the sample was sintered according to a certain program to close the pores and obtain a transparent glass body. This transparent glass body had a concentration distribution as shown in FIG.

Comparative Example-1 A sample in which cesium nitrate was sufficiently diffused into a porous glass body in the same manner as in Example-1 was immersed in a solution of ethanol and water at a volume ratio of 1:1 at 40°C to generate a concentration distribution. ta f
& The sample +1 was dried at 60°C.

Thereafter, the pores were closed under a certain program to obtain a transparent glass body. This transparent glass body had a concentration distribution as shown in the flS2 diagram.

As described above, the concentration distribution of the resulting glass body is clearly improved by immediately drying at a temperature of 150"C or more after creating a distribution in the sample 11 in which the dopant is uniformly soaked in hot water. I know what you're doing.

[Effects of the Invention] As described above, according to the present invention, immediately after causing distribution in sample P1 in which the dopant was uniformly soaked in hot water, 15
Since drying is performed at a temperature of 0° C. or higher, the -ta fixed dopant is not relaxed by movement of the solvent. Therefore, by making the porous body closed, a transparent glass body whose refractive index has a square distribution can be obtained.

Since the refractive index of the glass body thus obtained has a clean square law distribution, it can be applied to energy transmission glasses, SELFOC lenses, optical fiber base materials, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the concentration distribution of cesium in the glass body obtained in Example-1, and FIG. 2 is a diagram showing the concentration distribution of cesium in the glass body obtained in Comparative Example-1. Above (1st year of junior high school) (4F standard [radial direction] Fig. 1)

Claims (1)

[Claims] After dopant is diffused into porous glass, a sample is placed in a solvent to create a dopant concentration distribution, and then the dopant concentration distribution is fixed, and a gradient index glass body is obtained through drying and sintering. Optical transmission. In the dopant concentration distribution and the fixing of the dopant concentration distribution in the method for producing a glass body for use, a sample uniformly impregnated with the dopant is made to have a distribution in hot water, and then immediately dried at a temperature of 150°C or higher. A method for manufacturing a glass body for optical transmission.