JPH0250060B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a multilayer gel structure which is a raw material for optical glass bodies and which itself has various applications.

Recently, metal alkoxides (e.g. Si( _OCH3 ) ₄ )
The porous gel obtained by hydrolyzing the
Silica glass body doped with Zr, Ti, etc.)
A method for producing the sol-gel method (hereinafter referred to as the sol-gel method) has been proposed.

Figure 1 shows an overview of the sol-gel process. For example, Si(OCH ₃ ) ₄ is used as a raw material, and CH ₃ OH
and H ₂ O are mixed and stirred to prepare a raw material liquid 16 (11), and then transferred to a desired container 20 and gelled (this gel is hereinafter referred to as wet gel 17) (12). Next, the residual CH ₃ OH and H ₂ O are gradually dispersed and the silica gel is dried to form dry gel 18 (13), and then about 1000
The glass body 19 is obtained by sintering and vitrifying at a temperature of 0.degree. C. or higher (14).

The sol-gel method has the advantage of being an economical manufacturing method because it can synthesize a large amount of glass at a low temperature below the glass melting temperature.

In addition, porous dry silica gel has a specific surface area of about 800 m ^{3 /g and a pore diameter of about 800 m 3} /g, although it depends on the preparation conditions.
It is 20 to 100 Å, and if the gel state is an aggregate of fine particles, it corresponds to a collection of fine particles of about 100 Å.
Therefore, there are various applications such as selective permeation media that utilize pore interfaces, various reaction catalysts, and parts that convert directional light into pseudospherical waves using light scattering.

An object of the present invention is to provide a method for manufacturing a multilayer gel structure by a sol-gel method, and also to provide a method for manufacturing a multilayer gel structure having a structure that can be used as a raw material for optical components.

The purpose and method of the present invention will be explained below with reference to Examples.

Example 1 15.2 g of Si(OH ₃ ) ₄ , 14.4 g of methanol, distilled water
Mix and stir 7.2g, and the base is 10mm x 100mm high.
The mixture was filled into a 50 mm box-shaped glass container with a height of about 10 mm, and gelatinized at room temperature to form a fourth layer. Next, a raw material solution prepared by adding 0.5 g of Ge(OH ₃ ) ₄ to the above raw material solution was prepared and filled about 10 mm onto the fourth layer to gel the third layer. Similarly, 1g and 3g of Ge(OCH ₃ ) ₄
The raw material solution was sequentially gelled, and the remaining water and methanol were scattered to form a dry gel consisting of four layers as shown in FIG. 2. Here, the gel shrinks as it dries, and the amount of shrinkage varies depending on gelation and drying conditions such as temperature. Typically, a gel dried at 70°C for 10 days will shrink to about half the container shape. This example was also set under these conditions.
Therefore, care must be taken when obtaining a gel of a desired shape.

In order to impart mechanical strength to the resulting dried gel, it is subjected to a slight heat treatment (in O ₂ , N ₂ or inert gas).
200~800℃) from the left side of Figure 2.
The light from the He-Ne laser 21 is irradiated to the high refractive index layer (first layer 22) with a high Ge content, and
The scattered light (emitted from the surface of the layer 25) is detected by the power meter 26.
Detected with. The detection output decreased to about 10 ^-3 of the input, but when this scattered light was irradiated with a reflective display element (liquid crystal numeric display element) positioned so that the fourth layer surface was perpendicular to the display surface. It was found that the numbers on the element were easy to see in the sun and that omnidirectional light close to natural light could be obtained. Each layer 22, 23, 24,
The composition of 25 and the number and thickness of the layers are determined in correlation with the light source, the desired light state, and the amount of light. Therefore, it cannot be defined unambiguously, but for example, when using a highly directional laser beam, there should be 3 to 4 layers in consideration of light attenuation, and the light irradiation layer should have 3 to 4 layers to obtain the amount of scattered light. A composition with a high refractive index is desirable. Taking FIG. 2 as an example, the amount of scattered light can be increased by coating the outer surface of the first layer 22 with a reflective film such as Al. Above 200~800℃
Although the heat treatment is not necessary, mechanical strength and translucency are further improved by this treatment.

Note that frosted glass is simple and often used as a material for converting into the above-mentioned natural light (substantially non-directional light). However, with frosted glass, even the light from a normal lamp remains directional, making it difficult to create natural light. The present invention, which utilizes the light scattering properties of the gel state, makes it possible to easily see display elements such as number displays in dark places. In Figure 2,
23, 24, and 25 are the second layer, the third layer, and the fourth layer, respectively.

Example 2 15.2 g of Si(OCH ₃ ) ₄ , 14.4 g of methanol, distilled water
Ti( _OC3H7 ) ₄ as _a refractive index adjusting dopant to 7.2g
Fill a container with a length of 100 mm with 10 ml of raw material solution containing 3 g of 3 g added and mixed, and after gelling, place this wet gel in the center of a second container with a length of 20 ml and 100 mm. A second raw material solution containing 10 to 20 mol % of B alkoxide (B(OCH ₃ ) ₃ ), which lowers the softening temperature as a dopant, based on Si(OCH ₃ ) ₄ is added to the second raw material solution.
gel around the first gel in the container to form a second wet gel. Furthermore, in the same manner, the raw material solution containing no dopant was transferred to a third container (30 mm long).
100mm) to create a cylindrical gel with a three-layer structure, and after evaporating and drying the synergic water remaining in and around the gel (about 10 days at 70℃), it was heated slightly to give it mechanical strength. Processed. Processing conditions are 200~200 in _O2
It is 800℃. When the first layer at the center of the end face of the gel was irradiated with laser light, pseudo-natural light could be extracted onto the cylindrical circumference of the gel. This pseudo-natural light emitted in the circumferential direction can be combined with a numeric display element, similar to the plate-shaped multilayer gel, to facilitate visual recognition in a dark place.

When dry gel prepared in a similar manner was heated and sintered at approximately 1150°C, the second and third layers were made almost non-porous, except for the first layer in the center, which contains Ti, which has a high softening temperature. . When the first layer of the end face of the sample was irradiated with laser light, the amount of scattered light was lower than that of unsintered gel, but it was possible to create a light guide that partially contained bright spots, making it effective for decorative purposes. I understand. When the above sample was sliced into rings and the refractive index distribution in the radial direction of the cylindrical body was examined, a smooth distribution change in the refractive index was observed between each layer, which was thought to be due to dopant diffusion. It is thought that this indicates that the particles are fused and have good adhesion.

Example 3 A mother liquid containing Si(OCH ₃ ) ₄ described in Example 1 (referred to as the third raw material liquid) and a mother liquid containing 10 mol% of Ge and 30 mol% of B based on Si, respectively. Prepare the first and second raw material liquids, and place them in a first cylindrical container (5〓 length 100 mm) and a third cylindrical container (outer diameter 15〓, inner diameter 7〓 length 100 mm). Fill the container with the raw material liquid, close the container almost tightly, and heat it to 70℃.
gelatinized in a constant temperature chamber. Furthermore, the wet gels prepared in the first and third containers were placed concentrically in a second cylindrical container (15 mm, length 100 mm), and a second wet gel was placed in the gap between the first wet gel and the third wet gel.
Filled with raw material liquid. The gel was almost sealed again and gelatinized in a constant temperature oven at 70°C, and the degree of sealing was gradually reduced to create a dry gel. This dried gel was heated to approximately 1300°C to create a sintered non-porous glass body, and then an electric furnace at approximately 1900°C was used to form a glass thin wire with an outer diameter of approximately 150μ. This thin glass wire is what is called an optical fiber, and measurements showed that light entering from one end was transmitted approximately 100 meters to the other end, making it a low-loss light guide. Here, the composition and layer thickness of the second layer are selected depending on the type of light guide and the degree of adjustment of stress caused by the difference in thermal expansion of each layer.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view explaining the outline of each step in the sol-gel method, and Figure 2 is an explanatory diagram of the principle of light quality conversion by light scattering of a multilayer gel structure created in one embodiment of the present invention. be. 13... Obtained state of dry gel, 14...
Vitrified state, 16... Raw material liquid, 17...
Wet gel, 18...dry gel, 19...glass body, 21...laser, 26...power meter.

Claims (1)

[Scope of Claims] 1. A raw material solution that produces silica gel through a hydrolysis reaction is used, and the raw material solution contains or does not contain a compound of an additive element for adjusting the refractive index in a transparent quartz glass state, and A method for producing a multilayer gel structure, comprising the steps of sequentially gelling two or more of the raw material liquids using a mold, and removing gelling residue. 2 The multilayer gel structure is cylindrical or cylindrical 3
The method for producing a multilayer gel structure according to claim 1, wherein the multilayer gel structure has a concentric multilayer structure of more than one layer. 3. The method for producing a multilayer gel structure according to claim 2, wherein the refractive index of the innermost layer or central portion of the concentric multilayer structure is higher than that of the other layers.