JPS5950048A - Optical glass - Google Patents

Abstract

PURPOSE:To obtain SiO2-B2O3-La2O3-Nb2O5-ZrO2-TiO2-RO (R is an alkaline earth metallic element) glass having superior chemical durability and meltability, by specifying the amount of each of metallic oxides, the total amount of some of the oxides, and the weight ratio between some of the oxides. CONSTITUTION:This optical glass consists essentially of, by weight, 8-30% SiO2, 2-17% B2O3, 0-5% Al2O3 (SiO2+B2O3+Al2O3<=35%), 1-40% La2O3, 1-22% Na2O5, 1-10% ZrO2, 1-20% TiO2, 0-5% MgO, 0-6.5% CaO, 0-20% SrO, 0-30% BaO, 0-15% ZnO, 0-3% Li2O, 0-10% Na2O, 0-10% K2O, 0-1% As2O3 and 0-1% Sb2O3. The total amount of said components is 95-100%, and the ratio of B2O3/SiO2 is <=1.0. The glass has optical constants such as about 1.70-1.95 refractive index and about 25-50 Abbe's number.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 5i02 B2O3La2O3Nb205-ZrO2 having a refractive index (nd) of about 1.70-'1.95 and an Abbe number (vd) of about 25-50.
The present invention relates to a Ti02-RO (R is an alkaline earth metal element) optical glass.

Conventionally, glasses having optical constants equivalent to those of the glass of the present invention have been disclosed in Japanese Patent Publication No. 712) No. 1 and Japanese Patent Application Laid-open No. Sho) ↓8.
It is known from Japanese Patent Laid-Open No. 119-2140g and the like. These glasses are respectively B2O3-La2o3Z r02 Nb205
ZnO system, B2O3-La203-(BaO and/over ZnO)-Pb0-Li2o system and B2O3
5i02 La2O3BaO type glass etc.
It cannot be said that it is sufficiently good in terms of chemical durability, meltability, and light transmittance. In addition, Tokuko Showa 5-1
Similar glasses are also known in JP-A No. 87-0 and JP-A-48-23809, but all of the glasses shown in these documents contain G e 02, Gd2O3, Y
Expensive raw materials such as 2O3 and Ta205 must be used alone or in combination in relatively large amounts.

An object of the present invention is to provide a glass that has the above-mentioned predetermined optical constants and eliminates the above-mentioned drawbacks found in conventional glasses.

As a result of extensive testing and research to achieve this objective, the present inventor discovered that 8+02B203-La2O with a specific composition range.
We have discovered that there is a glass that exhibits excellent chemical durability and meltability among 3Nb205-Zr02-Ti02-RO (R is an alkaline earth metal element) type glass, leading to the present invention. .

The composition range of the optical glass according to the present invention to achieve the above object is 5i028 to 0% by weight, B20
32-17%, A12030-5%, however Si
02 +B203+A1203≦5% and B2
O3/SiO2≦1.0), La2O31~l+0%,
Nb2o51-22%, ZrO21-10%, Ti02
1-20%, just La203 +Nb205+Z
rO2≧17.5% and ZrO2+TlO2>5%
), Mg0O~5%, cao~6.5%, SrO0
-20%, BaO0-30%, MgO+CaO
+SrO+BaO15-less than 5%→, ZnO0-15
%, I, +20 0~%, Na 2 QO
-10%, K2O03'%, however LizO+
Na2O+Kz0 0~10%), Al12030~
1%, 5b2030~1%, but the total of each component above is 9
It needs to be 5-100%.

In the glass of the present invention, there is a tendency to strengthen the coloring property, which is thought to be due to the reduction of the TiO2 component in the glass depending on the melting conditions, but the inclusion of an alkali metal oxide component in the glass surprisingly alleviates this drawback. It is useful because it can be improved.

Next, the reason for limiting the composition range of each component of the optical glass according to the present invention as described above will be described.

That is, if the amount of Sr02 component is less than g% among 5i02 and B2O3, which are the main glass-forming oxide components of the glass of the present invention, the glass tends to devitrify, and it is difficult to produce a stable glass. If the amount exceeds 0%, it becomes difficult to satisfy the target optical constants. Furthermore, if the amount of the B2O3 component is less than 2%, the viscosity of the glass increases, making it difficult to obtain a homogeneous glass, and if the amount exceeds 17%, the chemical durability of the glass tends to deteriorate.

The 1203 component promotes the melting of glass raw materials and has the effect of improving chemical resistance and durability, so it can be added arbitrarily, but if its amount exceeds 5%, the devitrification of the glass will increase. .

However, the above S i 02, B2O3 and A120
If the sum of the three principal components exceeds 35%, it will be difficult to obtain the target optical constants. Furthermore, the weight ratio of the B2O3 component to the 5i02 component needs to be 1.0 or less in order to maintain excellent chemical durability.

The La2O3 component is necessary for the glass of the present invention because it increases the refractive index of the glass, and has the effect of increasing the Atsube number, but if its amount is less than 1%, the desired refractive index cannot be obtained, and the La2O3 component increases the refractive index of the glass. When the amount exceeds 40%, the devitrification of the glass increases.

The Nb2O5 component has the effect of increasing the refractive index of the glass, reducing the Atsube number, increasing the durability of the chemical reaction, and suppressing the tendency to devitrify, but if the amount is less than 1%, these effects are insufficient. However, if the amount exceeds 22%, it is not preferable because it will actually increase the devitrification of the glass.

The ZrO2 component has the effect of increasing the refractive index of the glass, improving the chemical durability, and suppressing the tendency to devitrify, but if the amount is less than 1%, these effects cannot be sufficiently obtained.
Moreover, if the amount exceeds 10%, the glass may produce unmelted substances during melting or become more likely to devitrify.

T! Component 02 has the effect of increasing the refractive index of glass, decreasing the Atsube number, and increasing chemical durability and stability against devitrification, but if the amount is less than 1%, these effects are not noticeable. , and when the amount exceeds 20%, the glass becomes strongly colored.

The sum of the three components of L&203, Nb2O5 and ZrO2, and the sum of the two components of ZrO2 and TiO□ are each The amount must be at least 17.5% and more than 5%.

Each of the alkaline earth metal oxide components MgO1Cab, SrO, and BaQ has the effect of promoting melting of the 5I02 raw material and suppressing the tendency of glass to devitrify when melting glass. However, when the amount of MgO and CaO exceeds 5% and 6.5%, respectively, devitrification increases, and when the amount of SrO exceeds 20%, devitrification increases and chemical durability deteriorates. Moreover, if the amount of BaO exceeds 30%, it is not preferable because chemical durability deteriorates.

Furthermore, if the total amount of one or more of these MgO1CaO1SrO and BaO components is less than 15%, the tendency of glass to devitrify increases significantly, and if it is more than 55%, the chemical durability deteriorates.

The ZnO component increases the refractive index of the glass and increases the 5i during melting.
It can be added because it has the effect of promoting the melting of the 02 raw material into the glass, but if its amount exceeds 5%, the chemical durability of the glass tends to deteriorate.

In the glass of the present invention, Li2O, Na2O and K
It is preferable to use any of the alkali metal oxide components of O since they have the effect of reducing the glass coloring tendency as described above. However, in order to maintain good chemical durability and fire permeability of the glass, it is desirable that the amounts of each of Li20, Na20 and Ni20 do not exceed 5%, 10% and 10%, respectively. For the same reason, the total amount of these two or more components is preferably within 10%.

Each component of A8□03 and 5b203 can be added up to 1% each as a defoaming and clarifying agent during glass melting.

In addition, in the glass of the present invention, pboSy other than the above
b2o3, Y2O3, Gd2O3, Ta2 osG e
The use of components such as O2 and WO2 is disadvantageous in terms of glass coloring, devitrification, raw material trace W property, etc., and is therefore undesirable, but especially when there is no problem in these respects,
One or more of these components can be added up to a total of 5%.

Next, Table 1 shows an example of the composition of the optical glass of the present invention, the optical constants (nd, vd) of the glass obtained from the composition, and the measurement results of the chemical durability test. Chemical durability test
Water resistance (RW (P)) and acid resistance (RA (p)) were measured according to the measurement method of Japan Optical Glass Industry Association standard JOGIS-OG. That is, standard sieve 420-5
Powdered glass samples that remain within 90 μm are heated to 99°C or above with reagents (pure water for water resistance tests, 0, 01 for acid resistance tests)
．． The weight loss rate (4) of the sample before and after the treatment was determined by treating the sample in a N nitric acid aqueous solution for 60 minutes, and classifying the sample into 6 classes based on the weight loss rate. Regarding water resistance test, class-1 is 0.05
Less than wt%, class-2 is less than 0.05 to 0110 wt%, and for acid resistance test, class-1 is 0.20 wt%.
less than, class-2 is 0.20-0. It is less than 5wt%.

In addition, in the present invention, Figure 1 (composition example
1 (alkali-free glass) and Wholesaler 2-lI (alkali-containing glass)) and Figure 2 (Comparison of practical composition example of the present invention, Flat 5 (alkali-free glass) and A6-g (alkali-containing glass)) Comparison). All glass samples were melted under constant melting conditions and have a thickness of 10 mm.

As shown in Table 1, the optical glasses of the composition examples of the present invention all have predetermined optical constants and are excellent in both water resistance and acid resistance. In addition, the glasses of the composition examples of the present invention containing the alkali metal oxide components shown in Figures 1 and 2 have a much higher light transmittance than glasses that do not contain this component, and have the effect of reducing coloration. It shows.

Although not shown, other composition examples of glasses containing an alkali component according to the present invention also have superior light transmittance.

(Hereinafter, blank space) As stated above, the optical glass according to the present invention is (
nd) approximately 1.70 to 1.95, (νd) approximately 25 to 50, and has superior chemical durability and raw material economy compared to conventional glasses. Adding a metal oxide component is useful because it can prevent deterioration of light transmittance due to changes in melting conditions and can also improve the meltability of the glass.

The optical glass of the present invention is produced by putting a raw material batch into a platinum crucible or the like, melting it at about 1200 to 100°C, stirring and removing bubbles, and then cooling it to about 1000 to 1150°C. It can be easily manufactured by casting it into a mold or the like and slowly cooling it.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are comparative curve diagrams showing the effect of improving spectral transmittance due to addition of an alkali component in composition examples of optical glasses of the present invention. Shouting to the Lord, Negi Rokushi is a small size glass-shaped hill F.
, 71-15- Written amendment (method) % formula % () () 1. Indication of the case 1982 Patent Application No. 159676 2. Name of the invention Optical glass 3. Person making the amendment Relationship to the case Patent applicant 4. Date of amendment order: January 5, 1982 (Shipping date: January 25, 1982)
Subject of amendment (1) Description 3, Detailed Description of the Invention Column 6, Contents of the amendment The engraving of the specification (no change in content) (1) Tables described on pages 12 to 14 of the specification - 1 shall be corrected as shown in Attached Table-1.

Claims (1)

[Claims] In weight%, 5iO38-60%, B2032-17%,
A12030~5%, where S i 02 +B2
03 +A7203≦35% and B203/540
2≦1.0), La2031~0%, Nb2051
-22%, ZrO21-10%, TIO21-20%
, However, L a203 +N b 205 +Z
r 02 ≧ 17.5%, and Z r 02 +T
i02-5%), Mg0O~5%, Ca00-6.5
%, 5r00~20%, Ba0O~30%, just M
gO+CaO+SrO+BaO15-ro less than 5% → Z
nO0-15%, Li2o o-ro%, Na2O0-
10%, K2O0~10%, just Lis+O1N
a20 +K 20 o~x 0%), A s 20
30 to 1%, 5b2030 to 1%, provided that the total of each of the above components is 95 to 100%.