JP7371846B2 - Optical glass, optical elements and optical equipment - Google Patents

Description

The present invention relates to an optical glass containing specific rare earth ions, an optical element using the same, and an optical instrument using the optical element.

Titanium-based oxide glasses, bismuth-based oxide glasses, and tellurium-based oxide glasses are known as high refractive index and high dispersion glasses. In the above glasses, titanium ions, bismuth ions, and tellurium ions have absorptions close to visible light in that order, giving high dispersion. However, the higher the dispersion, the more visible light is absorbed, the wavelength (nm) λ5 at which the transmittance is 5% becomes longer, and the glass becomes yellowish. Therefore, titanium-based oxide glass is often used in order to have a high refractive index and high dispersion and to make λ5 a shorter wavelength.

Patent Document 1 discloses titanium-based oxide glass. Furthermore, Patent Document 2 discloses a three-component glass of La ₂ O ₃ , TiO ₂ and SiO ₂ or a four-component glass of La ₂ O ₃ , TiO ₂ , SiO ₂ and ZrO ₂ .

International Publication No. 10/071202 JP2008-069047A

Since the glass described in Patent Document 1 contains SiO ₂ as an essential component, the refractive index decreases and the dispersion becomes low, making it difficult to obtain a glass with a high refractive index and high dispersion. Further, there was a problem that compositional fluctuations were likely to occur due to volatilization of SiO ₂ .

In addition, the glass described in Patent Document 2 is a titanium-based oxide glass, but since it has a high glass transition point, a glass mold lens in which the glass is softened using a mold to form a lens requires a high molding temperature. Therefore, there was a problem that the mold durability was inferior.

The present invention was made to solve these problems, and an object of the present invention is to provide an optical glass having a high refractive index, high dispersion, and a low glass transition point.

The optical glass of the present invention is an optical glass containing an oxide containing rare earth ions such as La ³⁺ , Y ³⁺ , Gd ³⁺ , Lu ³⁺ , and Yb ³⁺ and W ⁶⁺ and Nb ⁵⁺ ,
The content (cat%) of the rare earth ions relative to the total cations contained in the optical glass is 19 cat% or more and 30 cat% or less,
The content of W ⁶⁺ is 4 cat% or more and 70 cat% or less,
The content of Nb ⁵⁺ is 65 cat% or less,
The total content of Nb 5+ and Ti ⁴⁺ is 75 cat% or less ^,
It is characterized by an Abbe number of 16 or more and 24 or less.
The present invention also relates to an optical element having an optical glass having the above composition and an optical device using this optical element.

According to the present invention, a glass with a high refractive index, high dispersion, and a low glass transition point can be obtained. In particular, a transparent glass sphere having a refractive index nd at the d-line (587.56 nm) of 2.07 or more and 2.31 or less and an Abbe number νd of 16 or more and 24 or less can be obtained.

It is a conceptual diagram showing a gas jet floating device. It is a three-phase diagram of WO ₃ --NbO _5/2 --TiO ₂ when La ions are 30 cat%. It is a three-phase diagram of WO ₃ --NbO _5/2 --TiO ₂ when La ions are 27 cat%. It is a three-phase diagram of WO ₃ --NbO _5/2 --TiO ₂ when La ions are 24 cat%. It is a three-phase diagram of WO ₃ --NbO _5/2 --TiO ₂ when La ions are 22 cat%. It is a three-phase diagram of WO ₃ --NbO _5/2 --TiO ₂ when La ions are 20 cat%.

The present invention will be explained in detail below.
(optical glass)
The optical glass of the present invention has a high proportion of the total amount of specific rare earth ions (La ³⁺ , Y ³⁺ , Gd ³⁺ , Lu ³⁺ , Yb ³⁺ ions), W ⁶⁺ ions, Nb ⁵⁺ ions, and Ti ⁴⁺ ions as cations. It has a high refractive index and is transparent. Note that, hereinafter, the respective ions may be simply referred to as La ions, Y ions, Gd ions, Lu ions, Yb ions, W ions, Nb ions, and Ti ions. The same applies to ions other than those mentioned above.

A first aspect of the optical glass of the present invention is an optical glass containing an oxide containing a rare earth ion of La, Y, Gd, Lu, or Yb and a W ion, wherein the optical glass contains an oxide containing a rare earth ion and a W ion. The content (cat%) of the rare earth ions relative to the total ions is 19cat% or more and 30cat% or less, the W ion content is 4cat% or more and 70cat% or less, and the total content of Nb ions and Ti ions is 0cat%. % or more and 75 cat% or less, and the Abbe number is 16 or more and 24 or less. If the content of any of the above rare earth ions is less than 19 cat%, it is difficult to obtain a glass, and if it is more than 30 cat%, a highly dispersed glass cannot be obtained.

Among rare earth ions, La ions are a component for forming the network structure of glass, and La ions can be partially replaced with at least one or more ions selected from Y, Gd, Lu, and Yb ions. . Y ions can be substituted with 0 cat % or more and 15 cat % or less, Lu ions can be substituted with 0 cat % or more and 10 cat % or less, and Yb ions can be substituted with 0 cat % or more and 10 cat % or less. Further, Gd ions can be substituted in a range of 0 cat% to 20 cat%, and only Gd ions can be replaced with La ions in a total amount of 0 cat% to 20 cat%.

By containing Y, Gd, Lu, and Yb ions in the above ranges, the temperature difference ΔTx (Tx−Tg=ΔTx) between the crystallization start temperature (Tx) and the glass transition point (Tg) can be increased. Glass with a larger ΔTx has a wider temperature range from vitrification to crystallization, and thus has the effect of being easier to handle. If the content is less than the above range, the effect cannot be obtained, and if the content is more than the above range, the glass will crystallize.

The glass of the present invention contains W ions in a proportion of 4 to 70 cat% based on the total cations contained in the glass. The glass of the present invention preferably contains W ions in a range of 5 to 20 cat%. W ions are a component that has the effect of expanding the vitrification range and lowering the glass transition point. When the content of W ions is less than 4 cat%, the effect of lowering the glass transition point becomes small. If it exceeds 70 cat%, the glass becomes unstable and tends to crystallize (devitrify). Furthermore, the viscosity during melting becomes low, making it impossible to obtain a large glass body. Furthermore, during the production of a glass molded lens that is heated and molded using a mold, it tends to react with the mold and fuse.

The glass of the present invention can contain Nb ions in a proportion of 0 to 65 cat % based on the total cations contained in the glass. Nb ions in the glass partially function as a glass network forming component, and particularly function to impart a high refractive index. When Nb ions exceed 65 cat%, the glass becomes unstable and crystallizes (devitrification).

The glass of the present invention can contain Ti ions in a proportion of 0 cat % to 60 cat % based on the total cations contained in the glass. When the content is more than 60 cat%, the glass transition point increases. Further, λ5 becomes a long wavelength, which makes the glass yellowish, which is not preferable.

The glass of the present invention contains Nb ions and Ti ions as cations constituting the glass in a total proportion of 0 cat % or more and 75 cat % or less based on the total cations in the glass. It is preferably 56 cat% or more and 75 cat% or less. If the total proportion of these ions is more than 75 cat%, the glass becomes unstable and crystallized, which is not preferable.

In the glass of the present invention, the total amount of the three-component system of specific rare earth ions, W ions, and Ti ions, and specific rare earth ions, W ions, and Nb ions is 85 cat% or more based on the total cations contained in the glass. Preferably, it is more preferably 100 cat%. Furthermore, it is most preferable that the total amount of the four-component system of specific rare earth ion-W-Nb-Ti is 85 cat% or more, and the total amount is 100%. In the above range, compared to the network structure of conventional glass, the Ti-O bond and Nb-O bond exhibit a network structure with a high coordination number of 5.5 to 5.7 and edge sharing. By having four coordinations of -O, a glass with a high refractive index and a low glass transition point can be obtained.

The glass of the present invention contains Bi ions, Te ions, Ta ions, Zr ions, Zn ions, Mg ions, Ca ions, Ba ions, Si ions, B ions, Ge ions, Al ions, and Ga ions as optional components. ions or In ions. The proportions of the following optional components are based on the total cations contained in the glass. Note that the proportion of each cation contained in the finished glass can be measured by ICP (inductively coupled plasma) emission spectroscopy or the like.

The glass of the present invention can contain Bi ³⁺ ions and Te ⁴⁺ ions at 0 to 10 cat%. Bi ions and Te ions are components that provide high dispersion, but if Bi ions and Te ions exceed 10 cat %, the glass will be colored yellow and λ5 will deteriorate. Furthermore, the melt viscosity is low, making it impossible to obtain large glass spheres, and volatilization increases, making it impossible to obtain homogeneous glass.

The glass of the present invention can contain Ta ⁵⁺ ions from 0 cat% to 15 cat%. Ta ions have the effect of increasing ΔTx and high dispersion, but as Ta ions increase, the glass transition point increases, and if the amount exceeds 15 cat%, it tends to react with the mold and fuse during glass mold lens production. Become.

The glass of the present invention can contain Zr ⁴⁺ ions in a range of 0 cat% to 10 cat%. Zr ions have the effect of increasing ΔTx and high dispersion, but as the Zr ions increase, the glass transition point increases, and if the amount exceeds 10 cat%, it tends to react with the mold and fuse during the production of glass mold lenses. Become. Further, it acts as a crystal nucleus, and if the content exceeds 10 cat%, the glass will become devitrified. Since the glass transition point increases with an increase in Zr ions, it is more preferable not to add them.

The glass of the present invention can contain Zn ²⁺ ions, Mg ²⁺ ions, Ca ²⁺ ions, and Ba ²⁺ ions, each of 0 to 15 cat%. By containing Zn ions, Mg ions, Ca ions, and Ba ions, the value of λ5 can be reduced (improved). On the other hand, it also has the effect of increasing the Abbe number (lower dispersion). Therefore, if the content is 15 cat% or more, the Abbe number will increase and the dispersion will be low, making it impossible to obtain the desired high dispersion glass. Further, the glass transition point of Ca ion and Ba ion increases in proportion to the content.

However, among the four ions, Zn ions, Mg ions, Ca ions, and Ba ions, Zn ions have a small dispersion effect and lower the glass transition point Tg. This is the most suitable ion for lenses. Moreover, since Ba ions are equivalent to deleterious substances, it is more preferable not to include them. Furthermore, since Mg ions lower the refractive index, the content is preferably 10 cat% or less.

The glass of the present invention can contain Si ⁴⁺ ions from 0 cat% to 5 cat%. When contained in a small amount, it has the effect of lowering the glass transition point Tg, but when contained in an amount exceeding 5 cat%, crystallization occurs. On the other hand, since Si ions volatilize during heating during glass production, it is more preferable not to include Si ions.

The glass of the present invention can contain B ³⁺ ions and Ge ⁴⁺ ions in an amount of 0 cat% or more and 15 cat% or less, respectively. B ions and Ge ions lower the glass transition point Tg, and do not significantly change Δ56Tx within the above range. In addition, the effect of lowering the refractive index and lowering dispersion due to its inclusion is small. However, if the content exceeds 15 cat%, devitrification occurs.

The glass of the present invention can contain Al ³⁺ ions from 0 cat% to 15 cat%. Al ions have a great effect of reducing the dispersion of glass and also improve λ5. However, it has the effect of increasing the glass transition point Tg. If the content is more than 15 cat%, the Abbe number will exceed 24, resulting in low dispersion. It will crystallize again.

The glass of the present invention can contain Ga ³⁺ ions in a range of 0 cat% to 15 cat%. Ga ions are the second most useful ions next to Zn ions in terms of the effect of lowering the glass transition point Tg and the effect of increasing ΔTx, but they are more expensive than Zn ions.

The glass of the present invention can contain In ³⁺ ions from 0 cat% to 5 cat%. In ions have the effect of lowering the glass transition point Tg and increasing ΔTx, but if they are contained in an amount greater than 5 cat %, the glass will devitrify.

The glass of the present invention has a high refractive index nd at the d-line (587.56 nm) of 2.07 or more and 2.31 or less, more preferably 2.23 or more and 2.31 or less.

Further, the glass of the present invention has an Abbe number of 16 or more and 24 or less, more preferably 16 or more and 20 or less.

A second aspect of the optical glass of the present invention includes an oxide containing La ³⁺ , Ti ⁴⁺ , Nb ⁵⁺ , and W ⁶⁺ , and the content (cat%) of the entire cations contained in the optical glass is:
The La ³⁺ is 27 to 30 cat%, the total of the Ti ⁴⁺ , the Nb ⁵⁺ and the W ⁶⁺ is 70 to 73 cat%, and the following composition:
0 cat% ≦Ti ⁴⁺ ≦60 cat%,
0 cat% ≦Nb ⁵⁺ ≦60 cat%,
0 cat% ≦W ⁶⁺ ≦70 cat%,
It is characterized by satisfying the following.

Further, in the second aspect, the La ³⁺ is 30 cat%, the total of the Ti ⁴⁺ , the Nb ⁵⁺ and the W ⁶⁺ is 70 cat %, and the following composition:
0 cat% ≦Ti ⁴⁺ ≦60 cat%,
0 cat% ≦Nb ⁵⁺ ≦60 cat%,
10 cat% ≦W ⁶⁺ ≦70 cat%,
The filling,
Further, the present invention is characterized in that the Ti ⁴⁺ is 20 to 50 cat%, the Nb ⁵⁺ is 0 cat%, and the W ⁶⁺ is 20 to 50 cat%.

Furthermore, in the second aspect, the La ³⁺ is 27 cat%, the total of the Ti ⁴⁺ , the Nb ⁵⁺ and the W ⁶⁺ is 73 cat %, and the following composition:
3 cat% ≦Ti ⁴⁺ ≦53 cat%,
10 cat% ≦Nb ⁵⁺ ≦60 cat%,
10 cat% ≦W ⁶⁺ ≦60 cat%,
The filling,
Furthermore, the Ti ⁴⁺ is 3 cat%, the Nb ⁵⁺ is 20 to 30 cat%, and the W ⁶⁺ is 40 to 50 cat%, and the Ti ⁴⁺ is 23 to 43 cat%, the Nb ⁵⁺ is 10 cat%, and the W ⁶⁺ is is 20 to 40 cat%.

The raw material for the glass of the present invention can be selected from known materials such as oxides, hydroxides, carbonates, nitrates, and sulfates containing the above-mentioned cations depending on the glass production conditions.

(optical element)
The optical element of the present invention is obtained by molding the above optical glass. In this specification, an optical element refers to an element that constitutes an optical device such as a lens, a prism, a reflecting mirror, or a diffraction grating.

(Method for manufacturing optical glass)
The method for producing optical glass of the present invention is a containerless solidification method in which a sample is irradiated with a carbon dioxide laser to melt it, the melt is floated by a gas fluid ejected from a nozzle, and then cooled and solidified. As the gas type of the gas fluid, inert gases such as air, nitrogen, oxygen, argon, etc. can be used depending on the purpose. Further, the gas flow rate can be adjusted to 200 to 5000 ml/min depending on the floating of the melt.

Containerless solidification method refers to heating and melting materials such as Pt alloys (Pt or platinum alloys, such as Pt-Au, Pt-Au-Rh, etc.) and C-based materials (C, SiC, etc.) without using a container. After that, the glass is obtained by cooling and solidifying.

There are two major characteristics of the containerless coagulation method. The first is that since no container is used, there is no heterogeneous nucleation that occurs at the interface between the melt and the container, and a deep degree of cooling can be achieved. Second, since no container is used, it is possible to heat and melt samples that have a melting point higher than the conventional melting point of the container itself (for example, 1768° C. for Pt).

The main steps in the containerless solidification method are three steps: heating and melting the sample, floating the molten material obtained by heating and melting the sample, and turning off the heating source and cooling and solidifying.

In the step of heating and melting the sample, a laser heating source typified by a carbon dioxide laser, a high frequency heating source, a microwave heating source, an image furnace using a halogen lamp, etc. can be used as a heating source.

In the process of levitating a molten material, magnetic levitation, electrostatic levitation, sonic levitation, gas jet levitation, a combination of each (for example, sonic levitation and gas jet levitation), and microgravity conditions (for example, falling or outer space) may be used. I can do it.

In the step of cooling and solidifying the molten material in a floating state, transparent glass spheres can be obtained by cooling and solidifying at a cooling rate that does not generate crystals from the molten material.

[Example]
The present invention will be explained below using Examples.
In Examples 1 to 158, La ₂ O ₃ (LaF ₃ , La ₂ S ₃ ) and Y ₂ O were used as glass raw materials so that the composition of cations in the glass was the proportion of each sample shown in Table 1. ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ , Yb ₂ O ₃ , WO ₃ , Nb ₂ O ₅ , and TiO ₂ (TiS ₂ ) were weighed so that the total amount was 10 g. In addition, in the table, the term "total rare earth ions" means the total amount of rare earth ions in the raw materials.

In Comparative Examples 1 to 151, La ₂ O ₃ (LaF ₃ , La ₂ S ₃ ) and Y ₂ O were used as glass raw materials so that the composition of cations in the glass was the proportion of each sample shown in Table 2. ₃ , _{Gd2O3 , Lu2O3} , _Yb2O3 , _{WO3 , Nb2O5} , TiO2 ( _{TiS2 )} , _{Bi2O3 , TeO2 , Ta2O5 , ZrO2} , ZnO _, The total of MgO, CaO (CaCO ₃ ), BaO, SiO ₂ , B ₂ O ₃ (H ₃ BO ₃ ), GeO ₂ , Al ₂ O ₃ , Ga ₂ O ₃ , SnO ₂ , and In ₂ O ₃ is 10 g. It was weighed accordingly.

Thereafter, the glass raw materials were mixed for 15 minutes using an agate mortar so that they became uniform. In order to remove moisture from this mixture, it was fired in an electric furnace at 600°C for 7 hours. After filling a pressurized rubber mold with the fired powder, the mold was held at 20 kN for 1 minute using a cold isostatic press method. The resulting rod-shaped powder (powder compact) was fired at 1200°C for 7 hours to obtain a sintered body. (Also available as powder).

This sintered body 1 was set as a sample 2 on the nozzle 3 of the gas jet floating device shown in FIG. 1, and heated by irradiating it with a carbon dioxide laser 5 from above while flowing oxygen gas 4 at 500 ml/min from the nozzle hole. . The type of oxygen gas 4 may be dry air or nitrogen, as long as it can levitate the sample 2. Further, the gas amount can be adjusted as appropriate between 0.5 and 6 L/min depending on the size of the sintered body 1. The sintered body 1 set on the nozzle 3 of the gas jet floating device was heated, and after it became completely melted and levitation due to oxygen gas was confirmed, the laser output was cut off and the sintered body 1 was rapidly cooled to obtain the spherical sample 2. .

[Evaluation method]
(Vitrification judgment)
The spherical sample 2 was then observed with an optical microscope (100x magnification) to determine the presence or absence of crystals. In Tables 1 and 2, the diameters of the obtained spherical samples are divided into 2 mm (2φ) and 3 mm (3φ), and those in which no crystals were observed when observed with an optical microscope are marked with ○, and those with slight crystals. △ indicates that there is no problem as an optical glass even though crystals are observed, and × indicates that crystals are observed. In addition, when the diameter of the spherical sample is 2 mm, the effect of the present invention is fully exhibited, but when the diameter is 3 mm, the effect is more exhibited because the application uses are expanded.

(Measurement of glass transition point and ΔTx)
After crushing the spherical sample 2 in an agate mortar and filling it in a platinum pan with an outer diameter of 5 mm and a height of 2.5 mm, it was heated at a heating rate of 10°C/min using a Rigaku DSC8270 differential scanning calorimeter (DSC). It was heated to 1200°C and the glass transition point (Tg) was detected. The difference ΔTx (Tx−Tg=ΔTx) between the crystal initiation temperature Tx and the glass transition point Tg was determined.

(Refractive index measurement)
The refractive index and Abbe number were measured using KPR-2000 manufactured by Shimadzu Corporation after preparing two surfaces perpendicular to each other by polishing. When the sample was small, a transparent spherical sample was polished into a hemispherical shape and then measured using an ellipsometer (M-2000F manufactured by J.A. Woollam. Co., Inc.).

(Transmittance measurement)
Spectral transmittance including surface reflection was measured using a spectral transmittance device (UV-3100PC) manufactured by Shimadzu Corporation after biplane mirror polishing of the sample with a thickness of 0.5 mm. The wavelength (nm) showing a spectral transmittance of 5% at this time was expressed as λ5.

(Evaluation results)
Table 1 shows the results of Examples 1 to 158 of the obtained spherical samples. Table 2 shows the results of similar evaluations performed on the samples obtained in Comparative Examples 1 to 151.

As shown in Table 1, the optical No crystals were observed by microscopic observation, and a glass transition point was confirmed by measurement with a differential scanning calorimeter, making it possible to obtain a transparent glass sphere sample. Although crystals were observed in some samples with a diameter of 3 mm (3φ), no crystals were observed in any sample with a diameter of 2 mm (2φ).

The refractive index at the d-line (587.56 nm) was all 2.07 or higher. Moreover, the Abbe number (vd) was all 24 or less.

As shown in Table 2, among Comparative Examples 1 to 36 that do not contain WO ₃ , Comparative Examples 10 to 13, 18 to 19, 24, 28, and 33 to 36 cannot be used as optical glasses because crystals were observed. There was something. In addition, Comparative Examples 1 to 9, in which the content of rare earth ions is 27 cat% or more and 30 cat% or less, have glass transition points higher than 705°C, and Comparative Examples 10 to 36, in which the rare earth ion content is 20 cat% or more and less than 27 cat%. had a glass transition point higher than 690°C. These had higher glass transition points than the examples containing W ions shown in Table 1, making it difficult to obtain a glass mold. Furthermore, in Comparative Examples 37 to 151, optical glasses could not be obtained because crystals were observed.

Figure 2 shows a three-phase diagram plotting the results _{of Examples and Comparative Examples containing 30 cat% La 2 O 3} for the WO _{3 -TiO 2} -Nb ₂ O ₅ system. The case is shown in FIG. 3, the case of containing 24 cat% of La ₂ O ₃ is shown in FIG. 4, the case of containing 22 cat of La ₂ O ₃ is shown in FIG. 5, and the case of containing 20 cat of La ₂ O ₃ is shown in FIG. In each figure, the number of the example or comparative example is written in a circle.

Fig. 2 shows Comparative Examples 1 to 8 and Comparative Examples 37 to 40, Fig. 3 shows Comparative Examples 9 and Comparative Examples 41 to 46, and Fig. 4 shows Comparative Examples 10 to 18, Comparative Examples 47 to 59, and Comparative Examples 60 to 64. However, Comparative Examples 19 to 23 and Comparative Examples 65 to 70 in FIG. 5 and Comparative Examples 33 to 36 and Comparative Examples 71 to 90 in FIG. It shows that glass was obtained.

A third embodiment of the present invention will be described.
In FIG. 2, the compositions of La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , and Nb ⁵⁺ are as follows: Example 2 (30cat%, 10cat%, 60cat%, 0cat%) and Example 3 (30cat%, 0cat%, 70cat%, 0cat%). %), Example 9 (30cat%, 0cat%, 10cat%, 60cat%), Example 10 (30cat%, 50cat%, 10cat%, 10cat%), Example 20 (30cat%, 10cat%, 50cat%, Vitrification is performed in the first region surrounded by Example 2 (30 cat%, 10 cat%, 60 cat%, 0 cat%).

In FIG. 3, the compositions of La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , and Nb ⁵⁺ are Example 25 (27 cat%, 43 cat%, 10 cat%, 20 cat%) and Example 32 (27 cat%, 13 cat%, 40 cat%, 20 cat %), Example 33 (27cat%, 13cat%, 30cat%, 30cat%), Example 37 (27cat%, 3cat%, 30cat%, 40cat%), Example 39 (27cat%, 3cat%, 10cat%, 60 cat%) and Example 25 (27 cat%, 43 cat%, 10 cat%, 20 cat%) is vitrified.

In FIG. 4, the compositions of La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , and Nb ⁵⁺ are Example 40 (24 cat%, 26 cat%, 20 cat%, 30 cat%) and Example 45 (24 cat%, 16 cat%, 30 cat%, 30 cat %), Example 42 (24cat%, 16cat%, 60cat%, 0cat%), Example 48 (24cat%, 6cat%, 70cat%, 0cat%), Example 52 (24cat%, 6cat%, 30cat%, 40cat%), Example 55 (24cat%, 0cat%, 26cat%, 50cat%), Example 57 (24cat%, 0cat%, 6cat%, 70cat%), Example 41 (24cat%, 26cat%, 10cat%) , 40 cat%) and Example 40 (24 cat%, 26 cat%, 20 cat%, 30 cat%).

In FIG. 5, the compositions of La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , and Nb ⁵⁺ are Example 58 (22 cat%, 28 cat%, 10 cat%, 40 cat%) and Example 59 (22 cat%, 18 cat%, 20 cat%, 40 cat %), Example 60 (22cat%, 18cat%, 10cat%, 50cat%), and Example 58 (22cat%, 28cat%, 10cat%, 40cat%) are vitrified.

From these experimental results, it is found that the first composition lies on a line connecting any composition in the first region and any composition in any second region, with 27 cat% < La ³⁺ ≦ 30 cat%. is considered to be vitrified. Further, it is considered that the second composition, which is on a line connecting any one of the compositions in the second region and any one of the compositions in the third region, where 24 cat %<La ³⁺ ≦27 cat % is vitrified. Further, it is considered that the third composition, which is on a line connecting any one of the compositions in the third region and any one of the compositions in the fourth region, with 22 cat %≦La ³⁺ ≦24 cat %, is vitrified.

The glass of the third embodiment has one of the following compositions. The first composition is on the line connecting any composition of the first region and any composition of the second region when 27cat%<La ³⁺ ≦30cat%, and the second composition is on the line connecting any composition of the first region and any composition of the second region when 24cat%<La ³⁺ ≦27cat%. The second composition lies on a line connecting any composition of the region and any composition of the third region, or the composition of any one of the ^third region and the fourth A third composition is on a line connecting any of the compositions of the regions.

The glass of the third embodiment preferably satisfies the composition and physical properties described in the glass of the first embodiment.

The optical glass of the present invention can be molded into an optical element. Furthermore, this optical element can be used as an optical pickup lens for optical equipment, such as cameras, digital cameras, VTRs, DVDs, and the like.

1. Sintered body 2. Sample 3. Nozzle 4. Oxygen gas5. carbon dioxide laser

Claims (13)

An optical glass containing a rare earth ion of any one of La ³⁺ , Y ³⁺ , Gd ³⁺ , Lu ³⁺ , and Yb ³⁺ and an oxide containing W ⁶⁺ and Nb ⁵⁺ ,
The content (cat%) of the rare earth ions relative to the total cations contained in the optical glass is 19 cat% or more and 30 cat% or less,
The content of W ⁶⁺ is 4 cat% or more and 70 cat% or less,
The content of Nb ⁵⁺ is 65 cat% or less,
The total content of Nb ⁵⁺ and Ti ⁴⁺ is 75 cat% or less,
The content of Ti ⁴⁺ is 60 cat% or less,
The total content of the rare earth ions, W ⁶⁺ , Nb ⁵⁺ and Ti ⁴⁺ is 85 cat% or more,
An optical glass characterized by having a refractive index at the d-line of 2.05897 or more and 2.31 or less, an Abbe number of 16 or more and 24 or less , and a glass transition point of 731.2° C. or less . Additionally, the following composition:
0 cat% ≦Bi ³⁺ ≦10 cat%,
0 cat% ≦Te ⁴⁺ ≦10 cat%,
0 cat% ≦Ta ⁵⁺ ≦15 cat%,
0 cat% ≦Zr ⁴⁺ ≦10 cat%,
0 cat% ≦Zn ²⁺ ≦15 cat%,
0 cat% ≦Mg ²⁺ ≦15 cat%,
0 cat% ≦Ca ²⁺ ≦15 cat%,
0 cat% ≦Ba ²⁺ ≦15 cat%,
0 cat% ≦Si ⁴⁺ ≦5 cat%,
0 cat% ≦B ³⁺ ≦15 cat%,
0 cat% ≦Ge ⁴⁺ ≦15 cat%,
0 cat% ≦Al ³⁺ ≦15 cat%,
0 cat% ≦Ga ³⁺ ≦15 cat%,
0 cat% ≦In ³⁺ ≦5 cat%,
The optical glass according to claim 1, which satisfies the following. An optical glass containing an oxide containing a rare earth ion of La ³⁺ , Y ³⁺ , Gd ³⁺ , Lu ³⁺ , Yb ³⁺ and W ⁶⁺ ,
The content (cat%) of the rare earth ions relative to the total cations contained in the optical glass is 19 cat% or more and 30 cat% or less,
The content of W ⁶⁺ is 4 cat% or more and 70 cat% or less,
The total content of Nb ⁵⁺ and Ti ⁴⁺ is 0 cat% or more and 75 cat% or less,
The content of Nb ⁵⁺ is 65 cat% or less,
The content of Ti ⁴⁺ is 60 cat% or less,
The total content of the rare earth ions, W ⁶⁺ , Nb ⁵⁺ and Ti ⁴⁺ is 85 cat% or more,
The refractive index at the d-line is 2.05897 or more and 2.31 or less, the Abbe number is 16 or more and 24 or less , and the glass transition point is 731.2°C or less ,
Additionally, the following composition:
0 cat% ≦Bi ³⁺ ≦10 cat%,
0 cat% ≦Te ⁴⁺ ≦10 cat%,
0 cat% ≦Ta ⁵⁺ ≦15 cat%,
0 cat% ≦Zr ⁴⁺ ≦10 cat%,
0 cat% ≦Zn ²⁺ ≦15 cat%,
0 cat% ≦Mg ²⁺ ≦15 cat%,
0 cat% ≦Ca ²⁺ ≦15 cat%,
0 cat% ≦Ba ²⁺ ≦15 cat%,
0 cat% ≦Si ⁴⁺ ≦5 cat%,
0 cat% ≦B ³⁺ ≦15 cat%,
0 cat% ≦Ge ⁴⁺ ≦15 cat%,
0 cat% ≦Al ³⁺ ≦15 cat%,
0 cat% ≦Ga ³⁺ ≦15 cat%,
0 cat% ≦In ³⁺ ≦5 cat%,
Optical glass characterized by satisfying The optical glass according to any one of claims 1 to 3, wherein the content of W ⁶⁺ is 10 cat% or more and 70 cat% or less. The optical glass according to any one of claims 1 to 4, characterized in that the refractive index at the d-line is 2.07 or more and 2.31 or less. An optical glass containing an oxide containing a rare earth ion of La ³⁺ , Y ³⁺ , Gd ³⁺ , Lu ³⁺ , Yb ³⁺ and W ⁶⁺ ,
The content (cat%) of the rare earth ions relative to the total cations contained in the optical glass is 19 cat% or more and 30 cat% or less,
The content of W ⁶⁺ is 5 cat% or more and 20 cat% or less,
The total content of Nb ⁵⁺ and Ti ⁴⁺ is 56 cat% or more and 75 cat% or less,
The content of Nb ⁵⁺ is 65 cat% or less,
The content of Ti ⁴⁺ is 60 cat% or less,
The total content of the rare earth ions, W ⁶⁺ , Nb ⁵⁺ and Ti ⁴⁺ is 85 cat% or more,
An optical glass characterized by having a refractive index at the d-line of 2.23 or more and 2.31 or less, an Abbe number of 16 or more and 20 or less , and a glass transition point of 731.2° C. or less . The optical glass according to any one of claims 1 to 6, wherein the optical glass has a wavelength at which a spectral transmittance of 5% at a thickness of 0.5 mm is 385 nm or less. The optical glass according to any one of claims 1 to 7, wherein the optical glass has a glass transition point of 575°C or more and 729°C or less. An optical glass containing an oxide containing La ³⁺ and W ⁶⁺ , the composition of (La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , Nb ⁵⁺ ) is (30 cat%, 10 cat%, 60 cat%, 0 cat%), (30 cat %, 0cat%, 70cat%, 0cat%), (30cat%, 0cat%, 10cat%, 60cat%), (30cat%, 50cat%, 10cat%, 10cat%), (30cat%, 10cat%, 50cat%, 10cat%) and a first area surrounded by (30cat%, 10cat%, 60cat%, 0cat%),
The composition of (La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , Nb ⁵⁺ ) is (27cat%, 43cat%, 10cat%, 20cat%), (27cat%, 13cat%, 40cat%, 20cat%), (27cat%, 13cat%) , 30cat%, 30cat%), (27cat%, 3cat%, 30cat%, 40cat%), (27cat%, 3cat%, 10cat%, 60cat%) and (27cat%, 43cat%, 10cat%, 20cat%). a second area surrounded by
The compositions of (La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , Nb ⁵⁺ ) are (24cat%, 26cat%, 20cat%, 30cat%), (24cat%, 16cat%, 30cat%, 30cat%), (24cat%, 16cat%). %, 60cat%, 0cat%), (24cat%, 6cat%, 70cat%, 0cat%), (24cat%, 6cat%, 30cat%, 40cat%), (24cat%, 0cat%, 26cat%, 50cat%) , (24cat%, 0cat%, 6cat%, 70cat%), (24cat%, 26cat%, 10cat%, 40cat%) and a third area surrounded by (24cat%, 26cat%, 20cat%, 30cat%) ,
The composition of (La ³⁺ , Ti ⁴⁺ , W ⁶⁺ , Nb ⁵⁺ ) is (22cat%, 28cat%, 10cat%, 40cat%), (22cat%, 18cat%, 20cat%, 40cat%), (22cat%, 18cat%) , 10cat%, 50cat%) and (22cat%, 28cat%, 10cat%, 40cat%),
27 cat% < La ³⁺ ≦ 30 cat %, and the first composition is on a line connecting any composition of the first region and any composition of the second region, 24 cat % < La ³⁺ ≦ 27 cat %. A second composition that is on a line connecting any composition of the second region and any composition of the third region, or any one of the third region where 22 cat%≦La ³⁺ ≦24 cat% An optical glass characterized in that it has any one of the third compositions on a line connecting the composition of the above and the composition of any one of the fourth regions. An optical element having optical glass,
An optical element, wherein the optical glass is the optical glass according to any one of claims 1 to 9. The optical element according to claim 10, wherein the optical element is any one of a lens, a prism, and a mirror. An optical device having an optical element,
An optical device, wherein the optical element is the optical element according to claim 10 or 11. The optical device is a camera,
The optical device according to claim 12 , wherein the optical element is a lens .

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