JPS6022656B2 - optical glass - Google Patents

Description

Detailed Description of the Invention The present invention has a refractive index of 1.82 to 1.99 and an Abbe number of 27 to 45.
This invention relates to an optical glass having optical constants.

Some optical glasses having optical constants in the above-mentioned numerical range are already known, for example,
As seen in Publication No. 071y, it contains Tho2, or it contains Tho2, or it contains
It is customary to contain Gd203 and Y203 as essential components, as disclosed in Japanese Patent No. 4913.

However, Tho2 should not be used due to its radioactivity, and GOO3 and Y203 are GGG (Gd20 is also ○, 2).
With the advancement of applied technology for crystals, phosphors, etc., there is a growing concern that supply capacity will be insufficient. As a result of intensive research into glass systems that can reduce the content of Cd203 and Y203, including Tho2, the inventor found that &03-S;02-La203-
Yb203-Ta205 series〈Black 03-Si02-
It was found that the La203-YQ03-W03 system or a mixture of both systems met the purpose and was released.

YQ03, which is produced incidentally in the process of refining raw materials such as 203 and Y203, cannot be said to be abundant in terms of resources, but to date it has hardly been used, and raw material refining manufacturers also strongly desire to develop applications for it. It is rare. Glass systems containing YQ03 are already known from JP-A No. 51-2717, etc., but since they are shelf acid systems, it is extremely difficult to obtain the high refractive index glass contemplated by the present invention. It is difficult to obtain a stable glass. However, as in the present invention, a stable glass can be easily obtained by using a mixed system of shelf acid and citric acid. For example, the attached first
The diagram is &03-Si02-203-YQ03-Ta20
5 series string 03 = 7% by weight and Si02 = 7% by weight are shown, but &03-203-Yb
When B203 of the 203-Ta205 system is 14% by weight, no vitrified region exists.

Also, the attached Figure 2 shows B203-Si02-La203-
YQ03-W03 series B03 = 3% by weight, Si02 = 3
The vitrification area in weight% is shown &03-
When L is 03-YQ03-W03 and B203 is 6% by weight, no vitrification region exists. The present invention is based on the above findings, and essentially consists of &03-Si02-La203-YQ0
3-Ta2Q system or &03-Si02-W203-
Consisting of Yb203-W03 system or a mixture thereof, Th
The present invention provides a high refractive index, low dispersion optical glass that does not contain O2 and, if necessary, GQ03 or Y203.

That is, the optical glass according to the present invention has B03:2 to B03:2 by weight%.
9.5 Si02:2-10.5, evil203:20-5
0, Yb203:2-3 Ta2050W03:6-5
0 (but Ta205:0-2fuW03:0-50),
AI203:0-5, Ce02:0-12, Gq030Y203:0-25, Ti02:0-10, Z[)2:
0-8, Nb205: 0-10 1n2033 0-8
, Bi203: 0-8, Zn○: 0-1 or more Pbo: 0
~10Ba01S^]10Ca01Mg○: It has a composition of 0 to 10.

Next, the reasons for limiting each component are as follows: &03 and Si0
If 2 is 9.5% or more and 10.5% or more, a desired high refractive index cannot be obtained, and if each is 2% or less, a stable glass cannot be obtained.

La203, YQ03, Ta203, and W03 must be avoided because the glass becomes unstable if they deviate from their respective ranges. Also N203, Ge02, Gd203,
Y203, Ti02, Zh]2, NQ05, 1~03,
Bi03, Zn0, Pb0, Europe0, S, Cao, and M are added for the purpose of improving devitrification resistance, adjusting optical constants, improving meltability, etc., but they exceed the respective ranges. and,
This is undesirable because the glass becomes unstable, becomes strongly colored, or becomes difficult to melt.

In addition to these, small amounts of fluorine, alkali oxides, As20
3, SQ03, Sn02, etc. can also be added as necessary.
Next, examples of the present invention (components are weight %) and their performance will be shown. Table 1 The optical glass shown in Table 1 is made by heating a mixture of raw materials such as shelf acid, calcic acid, lanthanum oxide, ytterbium oxide, tantalum oxide, and tungsten oxide in a platinum crucible to a temperature of 1350 to 15
It is obtained by melting with 00CO, homogenizing it and removing bubbles, and then casting it into a mold heated at an appropriate temperature and slowly cooling it.

[Brief explanation of the drawing]

Figure 1 shows B203-Si02-La203-Yb203
- Figure 2 shows the vitrification region of B203 = 7% by weight and Si02 = 7% by weight in the Ta205 system.
The vitrification regions of B203=3 weight %, Si02=3 layers and 0 of the 2-French 203-YQ03-W03 system are shown, respectively. Figure 1 Figure 2

Claims (1)

[Claims] In 1% by weight, B_2O_3 2-9.5 SiO_2 2-10.5 La_2O_3 20-50 Yb_2O_3 2-35 Ta_2O_5+WO_3 6-50 However, Ta2O_5 0-25 WO_3 0-50 Al_2O_3 0-5 GeO_2 0~ 12 Gd_2O_3+Y_2O_3 0~25TiO_2
Optical glass having the following composition: 0-10 ZrO_2 0-8 Nb_2O_5 0-10 In_2O_3 0-8 Bi_2O_3 0-8 ZnO 0-10 PbO 0-10 BaO+SrO+CaO+MgO 0-10.