JPS61101426A - Production of light transmission glass material having refractive index gradient - Google Patents

Abstract

PURPOSE:To obtain stably and easily light transmission glass having refractive index gradient, by adding a metal alkoxide to raise refractive index to a specific silicon alkoxide solution to give wet gel, and immersing the gel in a metal- containing solution to reduce refractive index. CONSTITUTION:At least one of a metal alkoxide of elements of Ge, P, Al, etc. to raise refractive index of transparent quartz glass to a solution of a silicon alkoxide shown by the formula Si(OR)4 (R is alkyl group), which is hydrolyzed to give wet gel with a given shape. Then, the wet gel is immersed in a solution of a B-containing compound (B2O3, H3BO3, etc.) or a F-containing compound (NH4HF2, NaHF2, etc.) to reduce refractive index of transparent quartz glass. After the wet gel is provided with refractive index distribution, it is processed into dry gel, by a given method and made into glass by calcination. Consequently, light transmission glass material having refractive index continuously reducing from the center towards the peripheral direction is produced.

Description

Detailed Description of the Invention [Background and Objects of the Invention] The present invention relates to a light transmission glass body, particularly a light transmission glass having a refractive index gradient in which the refractive index of the glass gradually changes in a direction transverse to the direction in which the glass should travel. The present invention relates to a method of manufacturing a body.

As a method for manufacturing a light transmitting glass body in which the internal refractive index of the glass decreases continuously from the center toward the peripheral surface, for example, as shown in Japanese Patent Publication No. 47-816, a glass rod containing thallium is heated with alkali metal. A method is known in which the glass rod is melted and brought into contact with salt, and the thallium ions near the surface of the glass rod are replaced with more alkali total ions to obtain the required refractive index gradient. There are drawbacks such as ion exchange treatment taking time and poor weather resistance.Also, although imparting a refractive index is not the purpose, as shown in Japanese Patent Application Laid-open No. 58-9842, transparent quartz glass is added to a silicon alkoxide solution. A known method is to sinter and vitrify a solution containing an alkoxide, an additive element that changes the refractive index, in an organic solvent. In general, metal alkoxides have different hydrolysis rates, so if they are added multiple times, foaming cracks will occur during the sintering and vitrification process, and there are still points that need to be improved for practical use.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a method for manufacturing a light transmitting glass body having a refractive index gradient in which the internal refractive index of the glass decreases continuously toward the peripheral surface.

[Summary of the invention] The feature of the present invention is that when R is an alkyl group, the general formula Si
(OR) Add a metal alkoxide that increases the refractive index of transparent glass to a solution of silicon alkoxide represented by a, hydrolyze it to produce a wet gel of a predetermined shape, and use this wet gel to lower the refractive index of transparent quartz glass. A light transmitting glass whose refractive index continuously decreases from the center toward the peripheral surface by immersing it in a solution containing a metal that increases the refractive index and replacing the added metal that increases the refractive index in the wet gel with a metal that decreases the refractive index. The point is that the body was manufactured.

Here, as the silicon alkoxide represented by the general formula Si(OP)a, S! (OCH3)4.

S! (OCZ Ha)4,
S! (OC3FIT)a, etc., and these solutions contain Ge, P, All, Sb, Ti, Zr, Sn, To, and N, which increase the refractive index of transparent quartz glass.
A wet gel of a predetermined shape is created by adding at least one selected from metal alkoxides consisting of elements such as B and Go, and this wet gel is mixed with a B-containing compound or a F-containing compound that lowers the refractive index of transparent quartz glass. Soak in a solution of Compounds containing B Toshiteha, 8203, H3[303
, HBOz (NHa)BOz, KBOz, N
aBOz.

BBr3. 'B 13 , B6Hs, etc. can be used. F
Compounds containing Toshiteha, BrF3. NHaHF2.

NaHFz, KHFz, etc. can be used. After imparting a refractive index distribution to the wet gel in this way, Shirane et al.
Mat, Sc, 13 (1978), the process of forming a dry gel and sintering the dry gel to make it vitrified produced the desired light transmitting glass body. It's Nishide.

[Example] Hereinafter, a detailed explanation will be given based on examples.

Example 1 Ge (Q
Add 0.1 mol of CzHs)a, add 4 mol of CzHsO
Add H and mix well with a magnetic stirrer, add and mix 4 mol of 104 mol/1N HaOH aqueous solution, and as shown in Fig. Pour 70% into a silicone-coated cylindrical molding glass container 1,
The mixture is left to stand at 0°C to gel, forming a wet gel 3 as shown in FIG. After the wet gel 3 is separated from the glass container 1, the wet gel 3 is taken out from the glass container 1,
820320 in the glass container 4 as shown in FIG.
% 02H508 until the desired distribution is obtained. In this case, heating to 70° C. is effective in shortening the immersion time.

After soaking, take out the wet gel 3 and put it back into the original glass container 1.
It is evaporated at a rate of Q, 5 wt%/day based on the initial weight, and dried. Next, apply this wet gel 3 to 02
The temperature is raised to 700° C. in the chamber, and then sintered in an atmosphere containing HC to form a transparent glass body.

The dosing profile of the preform thus obtained is cut transversely to the axis of the glass body and the cross-section is polished by conventional means until completely transparent.

A thin carbon film was then deposited on the polished surface, and the coated surface was analyzed using a scanning electric microscope capable of X-ray analysis.

The concentration of Ge was high at the center and low at the periphery, and conversely, the concentration of B was almost non-existent at the center and high at the periphery.

Example 2 Ge (OCH
3) Add 0.1 mole of 4, add 4 mole of CH308, mix well with a magnetic stirrer, and add
Add and mix 4 mol of 4 mol/1 NHaOH aqueous solution,
Similar to Figure 1, this hydrolyzed solution was immediately poured into a tube with an inner diameter of 10ax.
The mixture was placed 70% into a silicone-coated cylindrical glass container 1 with a length of 200 m, and left to stand at 50°C to gel. After the gel is separated from the container, the gel is taken out from the glass container 1 and immersed in a 10% aqueous solution of NHallFz in the glass container 4 as shown in FIG. 3 until a desired distribution is obtained. In this case, heating is effective in shortening the soaking time. After immersion, the gel is taken out, put back into the original glass container 1, and dried by evaporation at a rate of 0.514 tX/day based on the initial weight. This gel is heated to 700° C. in O2, and then sintered in an atmosphere containing He to form a transparent glass body.

The addition distribution of the preform thus obtained was analyzed with a scanning electron microscope according to the method described above.

The concentration of Ge was high at the center and low at the periphery, and conversely, the concentration of F was almost non-existent at the center and high at the periphery.

Example 3 Ta (QC
2H6) and 2 moles of 02HaOH
was added and mixed well with a magnetic stirrer, and 4 mol of NHaOH aqueous solution with a concentration of 0.05N was added to the CZ H6.
Hydrolyzed water diluted with 0.082 mol was added dropwise over about 4 hours and mixed, and then immediately put into a cylindrical molding glass container 1 coated with silicone with an inner diameter of 10 am and a length of 2001 m at 7 vJ as in the first step. The mixture was allowed to stand at 50°C to form a gel. After the gel is separated from the container, the gel is taken out from the glass container 1 and immersed in a 10% HBO2 aqueous solution in the same manner as in FIG. 3 in a glass container 4 until a desired distribution is obtained. In this case, heating is effective in shortening the soaking time. After soaking, take out the gel and put it back into the original glass container 1, and add 0.5Wt to the initial weight.
Evaporate and dry at a rate of X/day.

This gel was heated to 700°C in 02, then He
It is sintered in an atmosphere containing a transparent glass body.

The addition distribution of the preform thus obtained was analyzed with a scanning electron microscope according to the method described above.

The concentration of Ta was high in the center and dilute in the outer periphery, and conversely, the concentration of B was almost non-existent in the center and high in the outer periphery.

[Effects of the Invention] As explained above, according to the present invention, the internal refractive index of the glass has a refractive index gradient that continuously decreases toward the peripheral surface, and the method for manufacturing a light transmission glass body is easy. This has the effect of creating a stable concentration distribution.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a cylindrical molding glass container containing Si(OR)4 hydrolyzed by adding a metal alkoxide to increase the refractive index, and Figure 2 is a cylindrical molding glass container containing gel. Figure 3 shows the gel separated from the container, and Figure 3 shows the gel immersed in a solution containing a compound that lowers the refractive index of the gel. 1... Cylindrical glass container for molding. 2... Hydrolyzed solution, 3... Wet gel. 4...Glass container, 5...Solution. Calculation 1. Calculation 2. 3rd closing

Claims (1)

[Claims] (1) When R is an alkyl group, the general formula Si(OR)_
A metal alkoxide that increases the refractive index of transparent glass is added to a solution of silicon alkoxide shown in 4, and the metal alkoxide that increases the refractive index of transparent glass is hydrolyzed to produce a wet gel of a predetermined shape. manufacturing a light transmission glass body whose refractive index continuously decreases from the center toward the peripheral surface by immersing it in a solution containing the liquid and replacing the added metal that increases the refractive index in the wet gel with a metal that decreases the refractive index. 1. A method of manufacturing a light transmitting glass body having a refractive index gradient, the method comprising: