JPS5913647A - Optical glass - Google Patents

Abstract

PURPOSE:To provide optical glass contg. B2O3, GeO2, La2O3, Gd2O3, ZrO2 and TiO2, having superior solubility and stability, and capable of increasing the refractive index. CONSTITUTION:This optical glass has a composition consisting of, by weight, 1-12% B2O3, 5-22% GeO2, 0-11% SiO2 (B2O3+GeO2+SiO2=14-30%), 20- 46% La2O3, 2-37% Gd2O3, 3-22% TiO2, 1-7% ZrO2, 0-27% Ta2O5, 0-12% PbO, 0-10% BaO, 0-10% ZnO, 0-12% Bi2O3, 0-12% In2O3 (PbO+BaO+ZnO+ Bi2O3+In2O3=0-12%) and 0-12% Al2O3. The glass has high solubility and superior devitrification resistance, and the optical constant distribution extends up to a higher refractive index region unlike conventional optical glass.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a refractive index tct of 1.89 to 2.02. Atsbe number 1), B2O3- has an optical constant of L26 to 38.
Ge02- La203-Gd203-ZrO□-'I
'Relating to i02 series optical glass.

Optical glasses whose optical constants fall within the above range are:

Although known in the art, these conventional glasses suffer from undesirable problems in their manufacture.

For example, JP-A-53-1-. 449] The glass described in Publication No. 3 contains glass-forming oxides B, 0. Extremely reduce the draw of La2(J3. Y2O,, Gd,
．． .

An attempt was made to obtain a high refractive index by increasing high valence components such as T a 205, but this type of optical glass was generally unstable and prone to devitrification, making it unsuitable for mass production. be. In addition, 1, for example, as seen in Japanese Patent Publication No. 54-2646, the glass-forming oxide is B, 03-4.
- There are also systems that are developed into a binary system of Si02 to improve devitrification resistance, but the drawback of these is that they are poorly soluble. The conventional optical glass shown as an example has a maximum refractive index of only around 1.95.

The present invention can solve all of the above-mentioned problems,
Moreover, the objective is to provide an optical glass that can have a much higher refractive index than conventional glasses. -Ge1J, -La203-Gd2(
J3.

- In the ZrC2 system, we have discovered that a large amount of TiO2 can be introduced in a region with little glass-forming oxide.

B20s-Ge obtained by introducing Ti0i into poly11i
O2-La 203- Gd203- Zr07- T
It has been found that iO-based glass has relatively good solubility and excellent devitrification resistance, and its optical constant distribution extends to an unprecedentedly high refractive index region.

On the other hand, the optical glass according to the present invention has a weight percentage of 820
, 1~12%, Ge025~22% Sin, 0~1
1% (However, B, 0.-1- Gem, +S 10
2=14-30%), La20. 20-46%
, Gd2 (J32-37%.

TlO23~22%, ZrO, j~7%, Ta,
U, O~27%, pbo O~12%, BaO
O~10%, Zn00~10%, Bi2030~
12%, In2030~12% (However, PbO
aO+ZnO+Bi2O3+In, 05=O~12%)
, Al2O, 0 to 12%.

In the optical glass having the above composition, *If B2O2 is less than 1%, devitrification tends to occur, and if it is 12% or more, the desired high refractive index glass cannot be obtained. Ge C2 is in the 5-22% O range, but when it goes into this range, a large amount of TiO2
((It is difficult to introduce, and on the other hand, if it exceeds the limit, the glass becomes difficult to melt.Ge The total amount of B, U, Ge(J, and St 02) needs to be 30% or less in order to maintain the desired high refractive index, but if it is 14% or less, the tendency to devitrify increases rapidly. .La, 0. and Gd2 (J, each 20~
46% and in the range of 2 to 37%, and outside this range, the devitrification resistance decreases. By coexisting with Gem2, Ti(J) increases the refractive index of the glass.

It helps to inhibit devitrification and makes it easier to dissolve.

If it is less than 3%, the effect will be small, and if it is more than 22%, the glass will become significantly colored, which is not preferable.

ZrU must be present in an amount of 1% or more to stabilize the glass, but if it is present in an amount of 7% or more, the tendency for devitrification becomes strong. , PbO, ZnC1, Ba
O, B+2 (J3゜In, 0. and Al2O, 1l-j
: The ranges described above (however, PbO-1-
ZnO-1-BaO+Bi, 0. -1- In, 03=
O~12%] contributes to increasing the devitrification resistance of the glass and adjusting the optical constants, but beyond this range the glass φ' becomes unstable.

Optical glass t according to the present invention, already mentioned JP-A-53-1
One of its features is that it has superior solubility and stability compared to the glasses of No. 44913 and Japanese Patent Publication No. 54-2646, and the following experiments were conducted to demonstrate this fact. That is, weighed with the raw material composition shown in Table 1 above,
Well-mixed Gutchi A, B and C (2 were kept at 1350°C in a platinum Lusze, Punch 8 melted in 1 hour, but Punch B and C were melted for 3 hours and 4 hours, respectively). It took time. Another molten substance? Regarding the glass obtained by casting, the glass from Nonotsuchi A was stable with no surface devitrification, but both the glasses from Nonotsuchi B and C had countless crystals mixed inside. This is recognized.

In addition, Table 1 Nakanotsuchi A corresponds to the composition of Table 11 pottery I listed below, and patch 13 corresponds to the composition No. 1 of JP-A-53-144913.
On the surface, it has a 9V composition, and it also has a 9V composition.
This corresponds to the composition of Table 2 A Nn 22 in No. 46.

Both the refractive index 9 and the refractive index 22 have compositions that have the highest refractive index in their respective patent documents.

Next, Examples of the present invention are shown in Table 3 along with refractive index and Abbe number.

(Left below) Optical glass having the composition shown in the table above is made by mixing oxides, carbonate groups, sulfates, hydroxides, etc. that are commonly used as glass raw materials, and heating this mixture in a platinum melt at 1300 to 1400°C.
It is obtained by melting with C, stirring to homogenize thoroughly, and after completely removing bubbles, pouring into a mold preheated at an appropriate temperature and slowly cooling.

Yasutani Glass Co., Ltd. Agent Masayuki Asakura

Claims (1)

[Claims] 1 Heavy phase percentage: B, 031~12%, GeO25~
22%, 5i020~11% (However, B2O3-1-Ge
m2-1-8 i02=14~30%), La2(
J, 20-46%, Gd, 032-37%. Tie, 3-22%, Zr0.1-7%, Ta2
O! lO~27%. PbO0~12%, 'Ba00~10%, ZnUO~1
0%. Bi2O, 0-12%, In, 030-12% (However, 1..pbo-4-BaO + Zn(J + B12O
3+In, 03=O~12%). Composition of Al2030~12%? Optical glass with.