TWI671269B

TWI671269B - Optical glass and optical components

Info

Publication number: TWI671269B
Application number: TW107123933A
Authority: TW
Inventors: 三上修平
Original assignee: 日商Ｈｏｙａ股份有限公司
Priority date: 2017-07-20
Filing date: 2018-07-11
Publication date: 2019-09-11
Also published as: JP2019019050A; CN109562978B; JP6517411B2; TW201908258A; CN109562978A

Abstract

本發明提供一種降低還原色的光學玻璃及光學元件。本發明的光學玻璃包含1～45質量%的B₂ O₃ 、10～60質量%的La₂ O₃ ，包含選自由TiO₂ 、Nb₂ O₅ 、WO₃ 及Bi₂ O₃ 而成之群組中的至少一個氧化物，且下述式(2)所示的βOH的值為0.1～2.0mm^-1 。βOH＝-[ln(B/A)]/t　···(2)。The invention provides an optical glass and an optical element for reducing reduced colors. The optical glass of the present invention contains 1 to 45% by mass of B ₂ O ₃ and 10 to 60% by mass of La ₂ O ₃ , and includes a group selected from the group consisting of TiO ₂ , Nb ₂ O ₅ , WO _3, and Bi ₂ O ₃ . At least one oxide in the group, and the value of βOH represented by the following formula (2) is 0.1 to 2.0 mm ^-1 . βOH =-[ln (B / A)] / t (2).

Description

光學玻璃及光學元件Optical glass and optical components

本發明關於光學玻璃及光學元件。The present invention relates to optical glass and optical elements.

近年來，隨著成像光學系、投影光學系等裝置的高性能化、緊湊化，作為有效的光學元件的材料，高折射率的光學玻璃的需求正在增高。In recent years, with the increasing performance and compactness of devices such as imaging optics and projection optics, as a material for effective optical elements, the demand for high-refractive index optical glass is increasing.

如專利文獻1所記載般之高折射率的光學玻璃通常大量地含有Ti、Nb、W、Bi等高折射率成分作為玻璃成分。此等成分在玻璃的熔融過程中容易被還原，被還原的此等成分因吸收可見光區域的短波長側的光，故成為玻璃的著色(以下，有時稱為「還原色」)的原因。 [先前技術文獻] [專利文獻]The optical glass having a high refractive index as described in Patent Document 1 usually contains a large amount of high refractive index components such as Ti, Nb, W, and Bi as glass components. These components are easily reduced during the melting process of the glass, and these reduced components absorb the light on the short wavelength side of the visible light region, and thus cause the coloration of the glass (hereinafter, sometimes referred to as "reduced color"). [Prior Art Literature] [Patent Literature]

專利文獻1：日本特開2007-112697號公報。Patent Document 1: Japanese Patent Application Laid-Open No. 2007-112697.

[發明所欲解決的問題][Problems to be solved by the invention]

本發明係鑑於此種實際情況而完成，目的在於提供降低還原色的光學玻璃及光學元件。 [用以解決問題的手段]The present invention has been made in view of such a situation, and an object thereof is to provide an optical glass and an optical element that reduce a reduction color. [Means to solve the problem]

本發明的要旨如下所述。 [1]一種光學玻璃，其包含1～45質量%的B₂ O₃ 、10～60質量%的La₂ O₃ ，包含選自由TiO₂ 、Nb₂ O₅ 、WO₃ 及Bi₂ O₃ 而成之群組中的至少一個氧化物，下述式(2)所示的βOH的值為0.1～2.0mm^-1 。 βOH＝-[ln(B/A)]/t　…(2) [式(2)中，t表示外部透射率的測定中使用的前述玻璃的厚度(mm)，A表示對前述玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對前述玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)。並且，ln為自然對數。]The gist of the present invention is as follows. [1] An optical glass comprising 1 to 45% by mass of B ₂ O ₃ and 10 to 60% by mass of La ₂ O _{3. The} optical glass is selected from the group consisting of TiO ₂ , Nb ₂ O ₅ , WO ₃ and Bi ₂ O ₃ . At least one of the oxides in the group has a βOH value represented by the following formula (2) of 0.1 to 2.0 mm ^-1 . βOH =-[ln (B / A)] / t (2) [In formula (2), t represents the thickness (mm) of the aforementioned glass used in the measurement of the external transmittance, and A represents the thickness of the aforementioned glass with respect to it. The external transmittance (%) at a wavelength of 2500 nm when light is incident in parallel directions, and B represents the external transmittance (%) at a wavelength of 2900 nm when light is incident on the glass in parallel with its thickness direction. And, ln is a natural logarithm. ]

[2]如[1]所記載之光學玻璃，其中，包含0.1～25質量%的SiO₂ 。[2] The optical glass according to [1], which contains 0.1 to 25% by mass of SiO ₂ .

[3]如[1]所記載之光學玻璃，其中，包含0.5～15質量%的SiO₂ 、1～30質量%的B₂ O₃ 、20～60質量%的La₂ O₃ 。[3] The optical glass according to [1], which contains 0.5 to 15% by mass of SiO ₂ , 1 to 30% by mass of B ₂ O ₃ , and 20 to 60% by mass of La ₂ O ₃ .

[4]如[1]～[3]中任一項所記載之光學玻璃，其中，以質量%表示，B₂ O₃ 的含量大於SiO₂ 的含量。[4] The optical glass according to any one of [1] to [3], wherein the content of B ₂ O ₃ is greater than the content of SiO ₂ in terms of mass%.

[5]如[1]～[4]中任一項所記載之光學玻璃，其中，TiO₂ 的含量相對於B₂ O₃ 及La₂ O₃ 的合計含量之質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]為0.030以上。[5] The optical glass of [1] to [4] set forth in any one of which, with respect to the mass of the total content of B ₂ O ₃ and La ₂ O ₃ ratio of the content of TiO ₂ [TiO ₂ / (B ₂ O ₃ + La ₂ O ₃ )] is 0.030 or more.

[6]如[1]～[5]中任一項所記載之光學玻璃，其中，阿貝數νd為20~45，折射率nd為1.75～2.50。[6] The optical glass according to any one of [1] to [5], wherein the Abbe number νd is 20 to 45 and the refractive index nd is 1.75 to 2.50.

[7]一種光學元件，其係由上述[1]～[6]中任一項所記載之光學玻璃而成。 [發明功效][7] An optical element comprising the optical glass according to any one of the above [1] to [6]. [Inventive effect]

根據本發明，可提供降低還原色的光學玻璃及光學元件。According to the present invention, it is possible to provide an optical glass and an optical element capable of reducing a reduction color.

以下，針對本發明的一態樣進行說明。此外，在本發明及本說明書中，玻璃組成只要沒有特別說明，則以氧化物基準表示。於此，所謂「氧化物基準的玻璃組成」係指作為在熔融時玻璃原料全部分解而在玻璃中以氧化物的形式存在的物質進行換算而得到的玻璃組成，各玻璃成分的符號依據慣例，記載為SiO₂ 、TiO₂ 等。玻璃成分的含量及合計含量只要沒有特別說明則為質量基準，「%」意指「質量%」，「ppm」意指「質量ppm」。Hereinafter, one aspect of the present invention will be described. In addition, in the present invention and the present specification, the glass composition is expressed on an oxide basis unless otherwise specified. Here, the "glass composition based on oxides" refers to a glass composition obtained by converting a glass raw material that is completely decomposed during melting and exists in the form of an oxide in the glass. The symbols of each glass component are based on convention. It is described as SiO ₂ , TiO ₂ and the like. The content and total content of glass components are mass standards unless otherwise specified. "%" Means "mass%" and "ppm" means "mass ppm".

玻璃成分的含量可藉由習知的方法，例如感應耦合電漿原子發射光譜儀(ICP-AES)、感應耦合電漿質譜儀(ICP-MS)等方法定量。並且，在本說明書及本發明中，所謂構成成分的含量為0%，意指實質上不包含此構成成分，允許以不可避免的雜質等級包含該成分。The content of the glass component can be quantified by conventional methods, such as inductively coupled plasma atomic emission spectrometer (ICP-AES), inductively coupled plasma mass spectrometer (ICP-MS), and the like. In addition, in the present specification and the present invention, the content of the constituent component is 0%, which means that the constituent component is not substantially contained, and the constituent is allowed to be contained in an unavoidable impurity level.

在本說明書中，只要沒有特別記載，則折射率係指在氦的d射線(波長587.56nm)之折射率nd。In this specification, unless otherwise specified, the refractive index refers to the refractive index nd of the d-ray (wavelength 587.56 nm) of helium.

阿貝數νd係用作為表示色散相關的性質的值，以下述式(1)表示。於此，nF為在藍色氫的F射線(波長486.13nm)之折射率，nC為在紅色氫的C射線(波長656.27nm)之折射率。 νd=(nd-1)/(nF-nC)　…(1)The Abbe number νd is a value representing a dispersion-related property, and is expressed by the following formula (1). Here, nF is the refractive index of F-rays (wavelength 486.13 nm) in blue hydrogen, and nC is the refractive index of C-rays (wavelength 656.27 nm) in red hydrogen. νd = (nd-1) / (nF-nC) ... (1)

本發明的實施形態之光學玻璃，包含1～45質量%的B₂ O₃ 、10～60質量%的La₂ O₃ ，包含選自由TiO₂ 、Nb₂ O₅ 、WO₃ 及Bi₂ O₃ 而成之群組中的至少一個氧化物，下述式(2)所示的βOH的值為0.1～2.0mm^-1 。 βOH＝-[ln(B/A)]/t　…(2) [式(2)中，t表示外部透射率的測定中使用的前述玻璃的厚度(mm)，A表示對前述玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對前述玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)。並且，ln為自然對數。]The optical glass according to the embodiment of the present invention includes 1 to 45% by mass of B ₂ O ₃ and 10 to 60% by mass of La ₂ O ₃ , and is selected from the group consisting of TiO ₂ , Nb ₂ O ₅ , WO _3, and Bi ₂ O _3. At least one oxide in the formed group has a βOH value represented by the following formula (2) of 0.1 to 2.0 mm ^-1 . βOH =-[ln (B / A)] / t (2) [In formula (2), t represents the thickness (mm) of the aforementioned glass used in the measurement of the external transmittance, and A represents the thickness of the aforementioned glass with respect to it. The external transmittance (%) at a wavelength of 2500 nm when light is incident in parallel directions, and B represents the external transmittance (%) at a wavelength of 2900 nm when light is incident on the glass in parallel with its thickness direction. And, ln is a natural logarithm. ]

以下，針對本實施形態之光學玻璃(以下，有時僅記載為為「玻璃」。)進行詳細說明。Hereinafter, the optical glass of the present embodiment (hereinafter, sometimes referred to simply as "glass") will be described in detail.

本實施形態之玻璃含有1～45%的B₂ O₃ 。B₂ O₃ 的含量的下限較佳為2%，進而依序更佳為3%、4%、6%。並且，B₂ O₃ 的含量的上限較佳為30%，進而依序更佳為25%、20%、15%。The glass of this embodiment contains 1 to 45% of B ₂ O ₃ . The lower limit of the B ₂ O ₃ content is preferably 2%, and more preferably 3%, 4%, and 6% in this order. In addition, the upper limit of the content of B ₂ O ₃ is preferably 30%, and more preferably 25%, 20%, and 15% in that order.

B₂ O₃ 為玻璃的網狀形成成分，具有維持低色散性、改善玻璃的熱穩定性的作用。另一方面，若B₂ O₃ 的含量多，則有玻璃熔融時玻璃成分的揮發量增加之虞。並且，有耐失透性下降的傾向。因此，B₂ O₃ 的含量較佳為上述範圍。B ₂ O ₃ is a network-forming component of glass, and has the effects of maintaining low dispersion and improving the thermal stability of glass. On the other hand, if the content of B ₂ O ₃ is large, the amount of volatilization of glass components may increase when the glass is melted. In addition, the devitrification resistance tends to decrease. Therefore, the content of B ₂ O ₃ is preferably in the above range.

本實施形態之玻璃含有10～60%的La₂ O₃ 。La₂ O₃ 的含量的下限較佳為20%，進而依序更佳為22%、24%、27%、30%。並且，La₂ O₃ 的含量的上限較佳為57%，進而依序更佳為55%、53%。The glass of this embodiment contains 10 to 60% of La ₂ O ₃ . The lower limit of the content of La ₂ O ₃ is preferably 20%, and further more preferably 22%, 24%, 27%, and 30% in this order. In addition, the upper limit of the content of La ₂ O ₃ is preferably 57%, and more preferably 55% and 53% in that order.

La₂ O₃ 具有提高折射率nd的作用。並且，亦具有提高化學耐久性的作用。另一方面，若La₂ O₃ 的含量變多則比重增加，並且玻璃的熱穩定性下降。因此，較佳為將La₂ O₃ 的含量設為上述範圍。La ₂ O ₃ has the effect of increasing the refractive index nd. It also has the effect of improving chemical durability. On the other hand, as the content of La ₂ O ₃ increases, the specific gravity increases, and the thermal stability of the glass decreases. Therefore, the content of La ₂ O ₃ is preferably set to the above range.

本實施形態之玻璃包含選自由TiO₂ 、Nb₂ O₅ 、WO₃ 及Bi₂ O₃ 而成之群組中的至少一個氧化物。TiO₂ 、Nb₂ O₅ 、WO₃ 及Bi₂ O₃ 皆為有助於高折射率化的成分，藉由包含此等成分，而能得到高折射率的光學玻璃。The glass of this embodiment contains at least one oxide selected from the group consisting of TiO ₂ , Nb ₂ O ₅ , WO ₃ and Bi ₂ O ₃ . TiO ₂ , Nb ₂ O ₅ , WO _3, and Bi ₂ O ₃ are all components that contribute to high refractive index. By including these components, a high refractive index optical glass can be obtained.

在本實施形態之玻璃中，下述式(2)所示的βOH的值為0.1～2.0mm^-1 。βOH的值的下限較佳為0.2mm^-1 ，進而依序更佳為0.25mm^-1 、0.3mm^-1 、0.35mm^-1 。並且，βOH的值的上限較佳為1.8mm^-1 ，進而依序更佳為1.6mm^-1 、1.5mm^-1 、1.4mm^-1 、1.2mm^-1 。 βOH＝-[ln(B/A)]/t　…(2)In the glass of this embodiment, the value of βOH represented by the following formula (2) is 0.1 to 2.0 mm ^-1 . The lower limit of the βOH value is preferably 0.2 mm ^-1 , and more preferably 0.25 mm ^-1 , 0.3 mm ^-1 , and 0.35 mm ^{-1 in this order} . In addition, the upper limit of the value of βOH is preferably 1.8 mm ^-1 , and more preferably 1.6 mm ^-1 , 1.5 mm ^-1 , 1.4 mm ^-1 , and 1.2 mm ^{-1 in this order} . βOH =-[ln (B / A)] / t… (2)

於此，在上述式(2)中，t表示外部透射率的測定中使用的上述玻璃的厚度(mm)，A表示對前述玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對前述玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)。並且，在上述式(2)中，ln為自然對數。βOH的單位為mm^-1 。Here, in the above formula (2), t represents the thickness (mm) of the glass used in the measurement of the external transmittance, and A represents the external transmission at a wavelength of 2500 nm when light is incident on the glass in parallel with its thickness direction. The ratio (%), B represents the external transmittance (%) at a wavelength of 2900 nm when light is incident on the glass in parallel with its thickness direction. Further, in the above formula (2), ln is a natural logarithm. The unit of βOH is mm ^-1 .

此外，所謂「外部透射率」，係指透過玻璃的透射光的強度Iout相對於入射到玻璃的入射光的強度Iin之比(Iout/Iin)，亦即，係亦考慮到在玻璃的表面之表面反射的透射率，透射率能藉由使用分光光度計測定透射光譜而得。In addition, the so-called "external transmittance" refers to the ratio (Iout / Iin) of the intensity Iout of the transmitted light transmitted through the glass to the intensity Iin of the incident light incident on the glass, that is, it also takes into account the The transmittance of the surface reflection can be obtained by measuring the transmission spectrum using a spectrophotometer.

上述式(2)所示的βOH意指由羥基導致的吸光度。因此，藉由評價βOH，而可評價玻璃中的水(及/或氫氧化物離子，以下，簡稱為「水」。)的含量。亦即，βOH高的玻璃意指玻璃中的水的含量高。ΒOH represented by the above formula (2) means absorbance due to a hydroxyl group. Therefore, by evaluating βOH, the content of water (and / or hydroxide ions, hereinafter simply referred to as "water") in the glass can be evaluated. That is, a glass with a high βOH means that the content of water in the glass is high.

藉由提高玻璃中的水的含量、提高βOH的值，而可降低還原色，縮短退火處理時間。並且，能得到脫泡、澄清效果。另一方面，若βOH的值過高，則有來自熔融玻璃的揮發物量增加的傾向。因此，較佳為將βOH的值設為上述範圍。By increasing the water content in the glass and increasing the βOH value, the reduction color can be reduced and the annealing treatment time can be shortened. In addition, defoaming and clarifying effects can be obtained. On the other hand, if the value of βOH is too high, the amount of volatiles from the molten glass tends to increase. Therefore, it is preferable to set the value of βOH to the above range.

提高玻璃的βOH的方法沒有特別限定，但可舉出例如：在熔融步驟中進行提高熔融玻璃中的水分量的操作等。作為提高熔融玻璃中的水分量的操作，可舉出例如：在熔融氣體環境中附加水蒸氣的處理、在熔融物內用包含水蒸氣的氣體進行鼓泡的處理等。The method of increasing the βOH of the glass is not particularly limited, and examples thereof include an operation to increase the amount of water in the molten glass in the melting step. Examples of the operation for increasing the water content in the molten glass include a process of adding water vapor in a molten gas environment, and a process of bubbling a gas containing water vapor in a molten material.

(玻璃成分) 以下針對本實施形態中之除上述以外的玻璃成分進行詳述。(Glass component) Hereinafter, the glass component other than the above in this embodiment is explained in full detail.

在本實施形態之玻璃中，SiO₂ 的含量的下限較佳為0.1%，進而依序更佳為0.5%、1%、1.5%、2%、3%。並且，SiO₂ 的含量的上限較佳為25%，進而依序更佳為15%、10%、8%、7%。In the glass of this embodiment, the lower limit of the content of SiO ₂ is preferably 0.1%, and more preferably 0.5%, 1%, 1.5%, 2%, and 3% in this order. The upper limit of the content of SiO ₂ is preferably 25%, and more preferably 15%, 10%, 8%, and 7% in that order.

SiO₂ 係玻璃的網狀形成成分，具有改善玻璃的熱穩定性、化學耐久性、耐候性的作用。另一方面，若SiO₂ 的含量多，則有玻璃的耐失透性下降之虞。因此，較佳為將SiO₂ 的含量設為上述範圍。The network-forming component of SiO ₂ based glass has the effect of improving the thermal stability, chemical durability, and weather resistance of the glass. On the other hand, if the content of SiO ₂ is large, the devitrification resistance of the glass may decrease. Therefore, the content of SiO ₂ is preferably set to the above range.

在本實施形態之玻璃中，P₂ O₅ 的含量較佳小於7%，進而依序更佳為5%以下、4%以下、3%以下、2%以下、1%以下。P₂ O₅ 的含量亦可為0%。In the glass of this embodiment, the content of P ₂ O ₅ is preferably less than 7%, and more preferably in order of 5% or less, 4% or less, 3% or less, 2% or less, and 1% or less. The content of P ₂ O ₅ may also be 0%.

P₂ O₅ 為使折射率nd下降的成分，亦為使玻璃的熱穩定性下降的成分。因此，較佳為將P₂ O₅ 的含量設為上述範圍。P ₂ O ₅ is a component that decreases the refractive index nd, and is also a component that decreases the thermal stability of the glass. Therefore, the content of P ₂ O ₅ is preferably set to the above range.

在本實施形態之玻璃中，Al₂ O₃ 的含量較佳為5%以下，進而依序更佳為4%以下、3%以下、2%以下、1%以下。Al₂ O₃ 的含量亦可為0%。In the glass of this embodiment, the content of Al ₂ O ₃ is preferably 5% or less, and more preferably 4% or less, 3% or less, 2% or less, and 1% or less in order. The content of Al ₂ O ₃ may also be 0%.

Al₂ O₃ 係具有改善玻璃的化學耐久性、耐候性之作用的玻璃成分，可當作網狀形成成分。另一方面，若Al₂ O₃ 的含量變多，則玻璃的耐失透性下降。並且，容易產生玻璃轉換溫度Tg上升、熱穩定性下降等問題。因此，Al₂ O₃ 的含量較佳為上述範圍。Al ₂ O ₃ is a glass component having the effect of improving the chemical durability and weather resistance of glass, and can be used as a network-forming component. On the other hand, when the content of Al ₂ O ₃ increases, the devitrification resistance of the glass decreases. In addition, problems such as an increase in the glass transition temperature Tg and a decrease in thermal stability easily occur. Therefore, the content of Al ₂ O ₃ is preferably in the above range.

在本實施形態之玻璃中，SiO₂ 及B₂ O₃ 的合計含量[SiO₂ +B₂ O₃ ]的下限較佳為2%，進而依序更佳為4%、6%、8%、10%。並且，合計含量[SiO₂ +B₂ O₃ ]的上限較佳為35%，進而依序更佳為30%、26%、24%、22%。In the glass of this embodiment, the lower limit of the total content of SiO ₂ and B ₂ O ₃ [SiO ₂ + B ₂ O ₃ ] is preferably 2%, and more preferably in order of 4%, 6%, 8%, 10%. In addition, the upper limit of the total content [SiO ₂ + B ₂ O ₃ ] is preferably 35%, and more preferably sequentially 30%, 26%, 24%, and 22%.

SiO₂ 及B₂ O₃ 為玻璃的網狀形成成分，為改善玻璃的熱穩定性及耐失透性的成分。因此，SiO₂ 及B₂ O₃ 的合計含量[SiO₂ +B₂ O₃ ]較佳為上述範圍。SiO ₂ and B ₂ O ₃ are network-forming components of the glass, and are components that improve the thermal stability and devitrification resistance of the glass. Therefore, the total content of SiO ₂ and B ₂ O ₃ [SiO ₂ + B ₂ O ₃ ] is preferably in the above range.

並且，在本實施形態之玻璃中，以質量%表示，較佳為B₂ O₃ 的含量[B₂ O₃ ]大於SiO₂ 的含量[SiO₂ ]([B₂ O₃ ]＞[SiO₂ ])。更佳為B₂ O₃ 的含量大於SiO₂ 的含量的1.3倍([B₂ O₃ ]＞[SiO₂ ]×1.3)。藉由使B₂ O₃ 的含量大於SiO₂ 的含量，而可增大阿貝數。Further, in the present embodiment in the form of a glass, in mass%, preferably B ₂ O ₃ content of [B ₂ O _3] is greater than the content of SiO ₂ [SiO _2] ([B ₂ O _3]> [SiO ₂ ]). The content of B ₂ O ₃ is more preferably 1.3 times the content of SiO ₂ ([B ₂ O ₃ ]> [SiO ₂ ] × 1.3). By making the content of B ₂ O ₃ larger than the content of SiO ₂ , the Abbe number can be increased.

在本實施形態之玻璃中，ZnO的含量的上限較佳為30%，進而依序更佳為25%、20%、15%、10%、7%、5%。並且， ZnO的含量較佳為超過0%，其下限更佳為0.1%，進而依序更佳為0.3%、0.5%、1%。In the glass of this embodiment, the upper limit of the content of ZnO is preferably 30%, and more preferably in order of 25%, 20%, 15%, 10%, 7%, and 5%. In addition, the content of ZnO is preferably more than 0%, and the lower limit thereof is more preferably 0.1%, and further more preferably 0.3%, 0.5%, and 1% in this order.

ZnO為具有改善玻璃的熱穩定性且改善玻璃的熔融性、化學耐久性的作用的玻璃成分。另一方面，若ZnO的含量過多則比重上升。因此，ZnO的含量較佳為上述範圍。ZnO is a glass component that has the effect of improving the thermal stability of glass, and improving the meltability and chemical durability of glass. On the other hand, if the content of ZnO is too large, the specific gravity increases. Therefore, the content of ZnO is preferably in the above range.

在本實施形態之玻璃中，BaO的含量的上限較佳為20%，進而依序更佳為19%、18%、17%、16%。並且，BaO的含量的下限較佳為0%，進而依序更佳為2%、5%、10%。In the glass of this embodiment, the upper limit of the content of BaO is preferably 20%, and more preferably 19%, 18%, 17%, and 16% in this order. In addition, the lower limit of the content of BaO is preferably 0%, and more preferably in order of 2%, 5%, and 10%.

BaO為有效維持高折射率的玻璃成分，並且，亦具有改善玻璃的熱穩定性及耐失透性的作用。另一方面，若含量變多，則比重增加，耐失透性下降。因此，BaO的含量較佳為上述範圍。BaO is a glass component that effectively maintains a high refractive index, and also has the effect of improving the thermal stability and devitrification resistance of glass. On the other hand, when the content is increased, the specific gravity is increased, and the devitrification resistance is decreased. Therefore, the content of BaO is preferably in the above range.

在本實施形態之玻璃中，MgO的含量的上限較佳為5%，進而依序更佳為4%、3%、2%、1%。並且，MgO的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of MgO is preferably 5%, and more preferably 4%, 3%, 2%, and 1% in this order. The lower limit of the content of MgO is preferably 0%.

在本實施形態之玻璃中，CaO的含量的上限較佳為10%，進而依序更佳為8%、6%、4%、2%。並且，CaO的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of CaO is preferably 10%, and more preferably in order of 8%, 6%, 4%, and 2%. The lower limit of the CaO content is preferably 0%.

在本實施形態之玻璃中，SrO的含量的上限較佳為7%，進而依序更佳為5%、4%、3%、1%。並且，SrO的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of SrO is preferably 7%, and more preferably 5%, 4%, 3%, and 1% in this order. The lower limit of the SrO content is preferably 0%.

MgO、CaO、SrO皆為具有改善玻璃的熱穩定性及耐失透性之作用的玻璃成分。另一方面，若此等玻璃成分的含量變多，則比重增加，高色散性受損，並且，玻璃的熱穩定性及耐失透性下降。因此，此等玻璃成分的各自含量分別較佳為上述範圍。MgO, CaO, and SrO are all glass components that have the effect of improving the thermal stability and devitrification resistance of glass. On the other hand, when the content of these glass components is increased, the specific gravity is increased, high dispersion is impaired, and the thermal stability and devitrification resistance of the glass are reduced. Therefore, the respective contents of these glass components are preferably in the above ranges.

在本實施形態之玻璃中，Gd₂ O₃ 的含量的上限較佳為35%，進而依序更佳為30%、25%、20%、17%、12%。並且，Gd₂ O₃ 的含量的下限較佳為0%，進而依序更佳為1%、3%、4%、5%。In the glass of this embodiment, the upper limit of the content of Gd ₂ O ₃ is preferably 35%, and more preferably 30%, 25%, 20%, 17%, and 12% in this order. In addition, the lower limit of the content of Gd ₂ O ₃ is preferably 0%, and more preferably in order of 1%, 3%, 4%, and 5%.

在本實施形態之玻璃中，Y₂ O₃ 的含量的上限較佳為25%，進而依序更佳為20%、15%、10%、7%、5%。並且，Y₂ O₃ 的含量的下限較佳為0%，進而依序更佳為1%、2%、3%。In the glass of this embodiment, the upper limit of the content of Y ₂ O ₃ is preferably 25%, and more preferably 20%, 15%, 10%, 7%, and 5% in order. In addition, the lower limit of the content of Y ₂ O ₃ is preferably 0%, and more preferably 1%, 2%, and 3% in that order.

Gd₂ O₃ 及Y₂ O₃ 皆為有助於耐候性的改善、高折射率化的成分。另一方面，若含量變得過多，則玻璃的熱穩定性下降，玻璃變得容易在製造中失透。因此，此等玻璃成分的各自含量分別較佳為上述範圍。Both Gd ₂ O ₃ and Y ₂ O ₃ are components that contribute to improvement of weather resistance and increase in refractive index. On the other hand, when the content is too large, the thermal stability of the glass is reduced, and the glass becomes liable to devitrify during production. Therefore, the respective contents of these glass components are preferably in the above ranges.

在本實施形態之玻璃中，Y₂ O₃ 的含量的上限較佳為5%，進而依次更佳為4%、3%、2%、1%。並且，Yb₂ O₃ 的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of Y ₂ O ₃ is preferably 5%, and more preferably 4%, 3%, 2%, and 1% in that order. The lower limit of the content of Yb ₂ O ₃ is preferably 0%.

Yb₂ O₃ 為有助於耐候性的改善、高折射率化的成分。另一方面，Yb₂ O₃ 因與La₂ O₃ 、Gd₂ O₃ 、Y₂ O₃ 相比分子量大，故使玻璃的比重增大。若玻璃的比重增大，則光學元件的質量增大。例如，若將質量大的透鏡組裝到自動對焦式的攝影機鏡頭中，則在自動對焦時，鏡頭的驅動所需要的電力增大，電池的消耗會變得劇烈。因此，期望降低Yb₂ O₃ 的含量，抑制玻璃的比重的增大。Yb ₂ O ₃ is a component that contributes to improvement of weather resistance and high refractive index. On the other hand, because Yb ₂ O ₃ has a larger molecular weight than La ₂ O ₃ , Gd ₂ O ₃ , and Y ₂ O ₃ , the specific gravity of glass is increased. When the specific gravity of glass is increased, the mass of the optical element is increased. For example, if a large-quality lens is incorporated into an autofocus camera lens, the power required for driving the lens will increase during autofocus, and battery consumption will become drastic. Therefore, it is desirable to reduce the content of Yb ₂ O ₃ and suppress an increase in the specific gravity of glass.

在本實施形態之玻璃中，ZrO₂ 的含量的上限較佳為18%，進而依序更佳為15%、12%、10%、8%、7%。並且，ZrO₂ 的含量的下限較佳為0%，進而依序更佳為1%、2%、3%。In the glass of this embodiment, the upper limit of the content of ZrO ₂ is preferably 18%, and more preferably 15%, 12%, 10%, 8%, and 7% in order. In addition, the lower limit of the content of ZrO ₂ is preferably 0%, and more preferably 1%, 2%, and 3% in that order.

ZrO₂ 為有助於高折射率化的成分，為具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。另一方面，若ZrO₂ 的含量過多，則表現出熱穩定性下降的傾向。因此，ZrO₂ 的含量較佳為上述範圍。ZrO ₂ is a component that contributes to higher refractive index, and is a glass component that has the effect of improving the thermal stability and devitrification resistance of glass. On the other hand, when the content of ZrO ₂ is too large, the thermal stability tends to decrease. Therefore, the content of ZrO ₂ is preferably in the above range.

在本實施形態之玻璃中，TiO₂ 的含量較佳為超過0%，其下限更佳為0.1%，進而依序更佳為1%、3%、4%、5%。並且，TiO₂ 的含量的上限較佳為30%，進而依序更佳為25%、23%、21%、20%。In the glass according to this embodiment, the content of TiO ₂ is preferably more than 0%, and the lower limit thereof is more preferably 0.1%, and further more preferably 1%, 3%, 4%, and 5% in order. The upper limit of the content of TiO ₂ is preferably 30%, and more preferably 25%, 23%, 21%, and 20% in that order.

TiO₂ 為有助於高折射率化的成分，並且，為發揮改善化學耐久性之作用的成分。另一方面，若TiO₂ 的含量過多，則有耐失透性下降之虞。因此，較佳為將TiO₂ 的含量設為上述範圍。TiO ₂ is a component that contributes to higher refractive index, and is a component that exhibits an effect of improving chemical durability. On the other hand, if the content of TiO ₂ is too large, the devitrification resistance may decrease. Therefore, the content of TiO ₂ is preferably set to the above range.

在本實施形態之玻璃中，Nb₂ O₅ 的含量的下限較佳為0.1%，進而依序更佳為1%、3%、4%、5%。並且，Nb₂ O₅ 的含量的上限較佳為35%，進而依序更佳為30%、25%、20%、16%、15%、14%、12%。In the glass of this embodiment, the lower limit of the content of Nb ₂ O ₅ is preferably 0.1%, and more preferably 1%, 3%, 4%, and 5% in order. In addition, the upper limit of the content of Nb ₂ O ₅ is preferably 35%, and more preferably 30%, 25%, 20%, 16%, 15%, 14%, and 12% in this order.

Nb₂ O₅ 為有助於高折射率化的成分，並且，具有改善玻璃的熱穩定性及化學耐久性之作用。另一方面，若Nb₂ O₅ 的含量過多，則有玻璃的熱穩定性下降之虞，並且，有玻璃的著色增強的傾向。因此，較佳為將Nb₂ O₅ 的含量設為上述範圍。Nb ₂ O ₅ is a component that contributes to a higher refractive index, and has a function of improving the thermal stability and chemical durability of glass. On the other hand, when the content of Nb ₂ O ₅ is too large, the thermal stability of the glass may decrease, and the coloring of the glass tends to be enhanced. Therefore, the content of Nb ₂ O ₅ is preferably set to the above range.

在本實施形態之玻璃中，Nb₂ O₅ 及TiO₂ 的合計含量[Nb₂ O₅ +TiO₂ ]的下限較佳為13%，進而依序更佳為13.5%、14%、14.5%、15%。並且，合計含量[Nb₂ O₅ +TiO₂ ]的上限較佳為40%，進而依序更佳為35%、32%、31%、30%。In the glass according to this embodiment, the lower limit of the total content of Nb ₂ O ₅ and TiO ₂ [Nb ₂ O ₅ + TiO ₂ ] is preferably 13%, and more preferably in order of 13.5%, 14%, 14.5%, 15%. In addition, the upper limit of the total content [Nb ₂ O ₅ + TiO ₂ ] is preferably 40%, and more preferably 35%, 32%, 31%, and 30% in this order.

Nb₂ O₅ 及TiO₂ 為有助於高折射率化的成分。另一方面，若Nb₂ O₅ 的含量過多，則玻璃的熱穩定性及耐失透性下降。因此，Nb₂ O₅ 及TiO₂ 的合計含量較佳為上述範圍。Nb ₂ O ₅ and TiO ₂ are components that contribute to higher refractive index. On the other hand, when the content of Nb ₂ O ₅ is too large, the thermal stability and devitrification resistance of the glass are reduced. Therefore, the total content of Nb ₂ O ₅ and TiO ₂ is preferably in the above range.

在本實施形態之玻璃中，WO₃ 的含量的上限較佳為25%，進而依序更佳為20%、15%、10%、5%。WO₃ 的含量的下限較佳為0%。In the glass of the present embodiment, the upper limit of the content of WO ₃ is preferably 25%, and more preferably in order of 20%, 15%, 10%, and 5%. The lower limit of the content of WO ₃ is preferably 0%.

WO₃ 具有使玻璃轉換溫度Tg下降的作用。另一方面，若WO₃ 的含量變得過多，則玻璃的著色增大且比重增加。因此，WO₃ 的含量較佳為上述範圍。WO ₃ has the effect of lowering the glass transition temperature Tg. On the other hand, when the content of WO ₃ becomes excessive, the coloration of the glass increases and the specific gravity increases. Therefore, the content of WO ₃ is preferably in the above range.

在本實施形態中，Bi₂ O₃ 的含量的上限較佳為20%，進而依序更佳為15%、10%、5%、3%。並且，Bi₂ O₃ 的含量的下限較佳為0%。In this embodiment, the upper limit of the content of Bi ₂ O ₃ is preferably 20%, and more preferably 15%, 10%, 5%, and 3% in that order. The lower limit of the content of Bi ₂ O ₃ is preferably 0%.

Bi₂ O₃ 具有藉由適量含有而改善玻璃的熱穩定性的作用。另一方面，若提高Bi₂ O₃ 的含量，則玻璃的著色增大且比重增加。因此，Bi₂ O₃ 的含量較佳為上述範圍。Bi ₂ O ₃ has an effect of improving the thermal stability of glass by containing it in an appropriate amount. On the other hand, when the content of Bi ₂ O ₃ is increased, the coloration of the glass increases and the specific gravity increases. Therefore, the content of Bi ₂ O ₃ is preferably in the above range.

在本實施形態之玻璃中，Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 的合計含量[Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ ]的上限較佳為40%，進而依序更佳為37%、35%、33%、32%。並且，合計含量[Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ ]的下限較佳為1.0%，進而依序更佳為1.5%、5%、10%、13%、13.5%、14%、14.5%、15%。In the glass of this embodiment, the upper limit of the total content [Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ ] of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ is preferably 40%. , And then better in order are 37%, 35%, 33%, 32%. In addition, the lower limit of the total content [Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ ] is preferably 1.0%, and more preferably in order of 1.5%, 5%, 10%, 13%, 13.5%, 14%, 14.5%, 15%.

TiO₂ 、WO₃ 及Bi₂ O₃ 與Nb₂ O₅ 皆為有助於高折射率化的成分。因此，合計含量[Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ ]較佳為上述範圍。TiO ₂ , WO ₃ , Bi ₂ O _3, and Nb ₂ O ₅ are all components that contribute to high refractive index. Therefore, the total content [Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ ] is preferably in the above range.

在本實施形態之玻璃中，TiO₂ 的含量相對於B₂ O₃ 及La₂ O₃ 的合計含量之質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]較佳為小，其下限較佳為0.030，進而依序更佳為0.035、0.040、0.045、0.050、0.055、0.060、0.065、0.070、0.075、0.080、0.085、0.090、0.095、0.10、0.15、0.20、0.25、0.30、0.35、0.40、0.45、0.50。並且，質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]的上限較佳為1.5，進而依序更佳為1.0、0.8、0.6。In aspect of this embodiment the glass, TiO ₂ content with respect to the mass of B ₂ O ₃ and the total content of La ₂ O ₃ is less than _{_{[TiO 2 / (B 2 O}} 3 + La 2 O 3)] preferred, The lower limit is preferably 0.030, and then more preferably in order: 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 , 0.40, 0.45, 0.50. In addition, the upper limit of the mass ratio [TiO ₂ / (B ₂ O ₃ + La ₂ O ₃ )] is preferably 1.5, and more preferably sequentially 1.0, 0.8, and 0.6.

在Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 中，質量%表示之每單位含量的折射率nd增加作用最大的成分為TiO₂ 。並且，TiO₂ 在熔融的過程中容易被還原，若TiO₂ 被還原時，則可見短波長區域的透射率容易大幅下降。另一方面，本實施形態之玻璃中，為主要成分的B₂ O₃ 及La₂ O₃ 不會產生此種因還原所致之問題。因此，較佳為相對於使可見短波長區域中之透射率大幅下降的TiO₂ 的含量，不會產生此種問題的B₂ O₃ 及La₂ O₃ 的合計含量大，亦即，質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]小。In Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ , the component having the largest effect of increasing the refractive index nd per unit content expressed by mass% is TiO ₂ . In addition, TiO ₂ is easily reduced during the melting process. When the TiO ₂ is reduced, it can be seen that the transmittance in the short-wavelength region is likely to decrease significantly. On the other hand, in the glass of this embodiment, B ₂ O ₃ and La ₂ O ₃ which are the main components do not cause such problems due to reduction. Therefore, it is preferable that the total content of B ₂ O ₃ and La ₂ O ₃ is larger than the content of TiO ₂ that significantly reduces the transmittance in the visible short wavelength region, that is, the mass ratio [TiO ₂ / (B ₂ O ₃ + La ₂ O ₃ )] is small.

在本實施形態之玻璃中，TiO₂ 的含量相對於Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 的合計含量之質量比[TiO₂ /(Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ )]的下限較佳為0.05，進而依序更佳為0.25、0.30、0.40、0.45。並且，質量比[TiO₂ /(Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ )]的上限較佳為1.00，進而亦可設為0.90、0.80、0.75。Glass aspect of this embodiment, TiO ₂ content with respect to the Nb _₂ O _5, ₂ mass of the total content of WO ₃ and Bi ₂ O ₃ to TiO, than _{_{[TiO 2 / (Nb 2 O}} 5 + TiO 2 + WO 3 The lower limit of + Bi ₂ O ₃ )] is preferably 0.05, and more preferably 0.25, 0.30, 0.40, and 0.45 in this order. In addition, the upper limit of the mass ratio [TiO ₂ / (Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ )] is preferably 1.00, and may also be 0.90, 0.80, or 0.75.

如上所述，TiO₂ 在熔融的過程中容易被還原，若TiO₂ 被還原，則可見短波長區域中之透射率容易大幅下降。於本實施形態，即使在Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 等有助於高折射率化的成分中尤以容易成為著色的原因之TiO₂ 的含量多，亦即，質量比[TiO₂ /(Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ )]為上述範圍之情況中，藉由在熔融步驟中在氣體環境中導入氣體、在熔融物中用氣體鼓泡，亦可抑制著色的增大。As described above, TiO ₂ is easily reduced during the melting process. If TiO ₂ is reduced, it can be seen that the transmittance in the short-wavelength region is likely to decrease significantly. In this embodiment, even in components that contribute to high refractive index, such as Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ , the content of TiO ₂ is more likely to cause coloration, that is, When the mass ratio [TiO ₂ / (Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ )] is in the above range, a gas is introduced into the gas environment during the melting step, and a gas is used in the melt. Bubbling can also suppress the increase in coloration.

在本實施形態之玻璃中，Ta₂ O₅ 的含量的上限較佳為25%，進而依序更佳為20%、16%、12%、8%、4%。並且，Ta₂ O₅ 的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of Ta ₂ O ₅ is preferably 25%, and more preferably in order of 20%, 16%, 12%, 8%, and 4%. The lower limit of the content of Ta ₂ O ₅ is preferably 0%.

Ta₂ O₅ 為有助於高折射率化的成分，亦具有改善玻璃的熱穩定性之作用。另一方面，若Ta₂ O₅ 的含量變多，則玻璃的熱穩定性下降，在熔融玻璃時，變得容易產生玻璃原料的熔融殘留。因此，Ta₂ O₅ 的含量較佳為上述範圍。Ta ₂ O ₅ is a component that contributes to higher refractive index, and also has the effect of improving the thermal stability of glass. On the other hand, when the content of Ta ₂ O ₅ is increased, the thermal stability of the glass is reduced, and when the glass is melted, it is easy to cause a molten residue of the glass raw material. Therefore, the content of Ta ₂ O ₅ is preferably in the above range.

在本實施形態之玻璃中，Li₂ O的含量的上限較佳為10%，進而依序更佳為7%、5%、4%、3%、2%、1%。Li₂ O的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of Li ₂ O is preferably 10%, and more preferably in order of 7%, 5%, 4%, 3%, 2%, and 1%. The lower limit of the content of Li ₂ O is preferably 0%.

在本實施形態之玻璃中，Na₂ O的含量的上限較佳為10%，進而依序更佳為7%、5%、4%、2%、1%。Na₂ O的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of Na ₂ O is preferably 10%, and more preferably in order of 7%, 5%, 4%, 2%, and 1%. The lower limit of the content of Na ₂ O is preferably 0%.

在本實施形態之玻璃中，K₂ O的含量的上限較佳為10%，進而依序更佳為7%、5%、4%、2%、1%。K₂ O的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of K ₂ O is preferably 10%, and more preferably in order of 7%, 5%, 4%, 2%, and 1%. The lower limit of the content of K ₂ O is preferably 0%.

Li₂ O、Na₂ O及K₂ O皆具有降低液相溫度、改善玻璃的熱穩定性之作用，但若此等含量變多，則化學耐久性、耐候性下降。因此，Li₂ O、Na₂ O及K₂ O的各含量分別較佳為上述範圍。Li ₂ O, Na ₂ O, and K ₂ O all have the effect of lowering the liquidus temperature and improving the thermal stability of the glass. However, if these contents are increased, the chemical durability and weather resistance will decrease. Therefore, the respective contents of Li ₂ O, Na ₂ O, and K ₂ O are preferably within the above ranges.

在本實施形態之玻璃中，Cs₂ O的含量的上限較佳為5%，進而依序更佳為4%、3%、2%、1%。Cs₂ O的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of Cs ₂ O is preferably 5%, and more preferably 4%, 3%, 2%, and 1% in this order. The lower limit of the Cs ₂ O content is preferably 0%.

Cs₂ O具有改善玻璃的熱穩定性之作用，但若此等含量變多，則化學耐久性、耐候性下降。因此，Cs₂ O的各含量較佳為上述範圍。Cs ₂ O has the effect of improving the thermal stability of the glass, but if these contents are increased, the chemical durability and weather resistance will decrease. Therefore, each content of Cs ₂ O is preferably in the above range.

在本實施形態之玻璃中，Li₂ O、Na₂ O、K₂ O及Cs₂ O的合計含量[Li₂ O+Na₂ O+K₂ O+Cs₂ O]的上限較佳為15%，進而依序更佳為10%、7%、5%、3%、1%。並且，合計含量[Li₂ O+Na₂ O+K₂ O+Cs₂ O]的下限較佳為0%。In the glass of this embodiment, the upper limit of the total content [Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O] of Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O is preferably 15%. , And then better in order is 10%, 7%, 5%, 3%, 1%. The lower limit of the total content [Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O] is preferably 0%.

[0081]藉由合計含量[Li₂ O+Na₂ O+K₂ O+Cs₂ O]的下限滿足上述，而可改善玻璃的熔融性及熱穩定性，降低液相溫度。並且，藉由合計含量[Li₂ O+Na₂ O+K₂ O+Cs₂ O]的上限滿足上述，而可抑制耐失透性的下降。[0081] When the lower limit of the total content [Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O] satisfies the above, the melting property and thermal stability of glass can be improved, and the liquidus temperature can be reduced. In addition, when the upper limit of the total content [Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O] satisfies the above, a reduction in devitrification resistance can be suppressed.

在本實施形態之玻璃中，Sc₂ O₃ 的含量較佳為2%以下。並且，Sc₂ O₃ 的含量的下限較佳為0%。In the glass of this embodiment, the content of Sc ₂ O ₃ is preferably 2% or less. The lower limit of the content of Sc ₂ O ₃ is preferably 0%.

在本實施形態之玻璃中，HfO₂ 的含量的上限較佳為2%以下，進而依序更佳為1%、0.5%、0.1%。並且，HfO₂ 的含量的下限較佳為0%。In the glass of this embodiment, the upper limit of the content of HfO ₂ is preferably 2% or less, and more preferably 1%, 0.5%, and 0.1% in this order. The lower limit of the content of HfO ₂ is preferably 0%.

Sc₂ O₃ 、HfO₂ 具有提高玻璃的高色散性之作用，但為昂貴的成分。因此，Sc₂ O₃ 、HfO₂ 的各含量較佳為上述範圍。Sc ₂ O ₃ and HfO ₂ have the effect of improving the high dispersion of glass, but are expensive components. Therefore, each content of Sc ₂ O ₃ and HfO ₂ is preferably in the above range.

在本實施形態之玻璃中，Lu₂ O₃ 的含量較佳為2%以下。並且，Lu₂ O₃ 的含量的下限較佳為0%。In the glass of this embodiment, the content of Lu ₂ O ₃ is preferably 2% or less. The lower limit of the content of Lu ₂ O ₃ is preferably 0%.

Lu₂ O₃ 具有提高玻璃的高色散性之作用，但由於分子量大，故亦為使玻璃的比重增加的玻璃成分。因此，Lu₂ O₃ 的含量較佳為上述範圍。Lu ₂ O ₃ has the effect of improving the high dispersion of glass, but because of its large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the content of Lu ₂ O ₃ is preferably in the above range.

在本實施形態之玻璃中，GeO₂ 的含量較佳為2%以下。並且，GeO₂ 的含量的下限較佳為0%。In the glass of this embodiment, the content of GeO ₂ is preferably 2% or less. The lower limit of the content of GeO ₂ is preferably 0%.

GeO₂ 具有提高玻璃的高色散性之作用，但在通常使用的玻璃成分中，為特別昂貴的成分。因此，從降低玻璃的製造成本的觀點而言，GeO₂ 的含量較佳為上述範圍。GeO ₂ has the effect of improving the high dispersion of glass, but it is a particularly expensive component among commonly used glass components. Therefore, from the viewpoint of reducing the manufacturing cost of glass, the content of GeO ₂ is preferably in the above range.

本實施形態之玻璃，較佳為主要由上述的成分，亦即，作為必需成分的B₂ O₃ 及La₂ O₃ ，作為任意成分的SiO₂ 、P₂ O₅ 、Al₂ O₃ 、ZnO、BaO、MgO、CaO、SrO、Gd₂ O₃ 、Y₂ O₃ 、Yb₂ O₃ 、ZrO₂ 、TiO₂ 、Nb₂ O₅ 、WO₃ 、Bi₂ O₃ 、Ta₂ O₅ 、Li₂ O、Na₂ O、K₂ O、Cs₂ O、Sc₂ O₃ 、HfO₂ 、Lu₂ O₃ 及GeO₂ 構成，上述的玻璃成分的合計含量較佳為設為大於95%，更佳為設為大於98%，再佳為設為大於99%，進而較佳為設為大於99.5%。The glass of this embodiment is preferably composed of the above-mentioned components, that is, B ₂ O ₃ and La ₂ O ₃ as essential components, and SiO ₂ , P ₂ O ₅ , Al ₂ O ₃ , and ZnO as optional components. , BaO, MgO, CaO, SrO, Gd ₂ O ₃ , Y ₂ O ₃ , Yb ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, Sc ₂ O ₃ , HfO ₂ , Lu ₂ O ₃ and GeO _2. The total content of the above glass components is preferably set to greater than 95%, more preferably It is set to more than 98%, more preferably to more than 99%, and more preferably to more than 99.5%.

在本實施形態中，作為進一步較佳的方式，可舉出：光學玻璃，其包含1～45%的B₂ O₃ 、10～60%的La₂ O₃ 、超過0%的TiO₂ 、超過0%的ZnO； TiO₂ 的含量相對於Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 的合計含量之質量比[TiO₂ /(Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ )]為0.4以上；且下述式(2)所示的βOH的值為0.1～2.0mm^-1 。 βOH＝-[ln(B/A)]/t　…(2) [式(2)中，t表示用於外部透射率的測定之前述玻璃的厚度(mm)，A表示對前述玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對前述玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)。並且，ln為自然對數。]In this embodiment, as a more preferable aspect, an optical glass may be mentioned, which includes 1 to 45% of B ₂ O ₃ , 10 to 60% of La ₂ O ₃ , more than 0% of TiO ₂ , and more than of 0% of ZnO; content of TiO ₂ with respect to the Nb _₂ O _5, _2, mass of the total content of TiO WO ₃ and Bi ₂ O ₃ ratio of _{_{[TiO 2 / (Nb 2 O}} 5 + TiO 2 + WO 3 + Bi 2 O ₃ )] is 0.4 or more; and the value of βOH represented by the following formula (2) is 0.1 to 2.0 mm ^-1 . βOH =-[ln (B / A)] / t (2) [In the formula (2), t represents the thickness (mm) of the aforementioned glass used for the measurement of external transmittance, and A represents the thickness of the aforementioned glass relative to its thickness. The external transmittance (%) at a wavelength of 2500 nm when light is incident in parallel directions, and B represents the external transmittance (%) at a wavelength of 2900 nm when light is incident on the glass in parallel with its thickness direction. And, ln is a natural logarithm. ]

針對上述進一步較佳的態樣中之B₂ O₃ 、La₂ O₃ 、TiO₂ 及ZnO的含量、質量比[TiO₂ /(Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ )]以及βOH的值，可應用前述的更佳的數值範圍。並且，針對其他玻璃成分的含量及質量比，亦可適當應用前述的較佳的數值範圍。Aiming at the above-mentioned further preferable aspects, the content and mass ratio of B ₂ O ₃ , La ₂ O ₃ , TiO ₂ and ZnO [TiO ₂ / (Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ ) ] And βOH values, the aforementioned better numerical range can be applied. In addition, for the content and mass ratio of other glass components, the aforementioned preferred numerical ranges may be appropriately applied.

在本實施形態之玻璃中，鉑Pt的含量較佳小於10ppm，進而依序更佳為8ppm以下、7ppm以下、5ppm以下。Pt的含量的下限沒有特別限定，但不可避免地包含0.001ppm左右。In the glass of this embodiment, the content of platinum Pt is preferably less than 10 ppm, and more preferably 8 ppm or less, 7 ppm or less, and 5 ppm or less in this order. The lower limit of the content of Pt is not particularly limited, but inevitably contains about 0.001 ppm.

藉由將Pt的含量設為上述範圍，而可降低由Pt導致之玻璃的著色，改善透射率。By setting the content of Pt to the above range, the coloration of glass caused by Pt can be reduced, and the transmittance can be improved.

本實施形態之玻璃，在其製造步驟中，在非氧化性氣體環境中熔融玻璃原料。作為非氧化性氣體環境，可舉出例如：氮、二氧化碳、氬、氦等非活性氣體、水蒸氣。通常，熔融氣體環境中的氧與為熔融容器(坩堝等)等材料之鉑進行反應，生成二氧化鉑、鉑離子(Pt⁴⁺ )，其溶入熔融玻璃中，由此產生著色。於本實施方式，藉由降低熔融氣體環境中的氧分壓，可抑制鉑的氧化，降低溶入熔融玻璃中的Pt量。其結果，可降低來自Pt的著色。In the manufacturing process of the glass of this embodiment, glass raw materials are melted in a non-oxidizing gas environment. Examples of the non-oxidizing gas environment include inert gases such as nitrogen, carbon dioxide, argon, and helium, and water vapor. Generally, oxygen in a molten gas environment reacts with platinum, which is a material such as a melting vessel (crucible, etc.), to generate platinum dioxide and platinum ions (Pt ⁴⁺ ), which are dissolved in the molten glass, thereby causing coloration. In this embodiment, by reducing the oxygen partial pressure in the molten gas environment, the oxidation of platinum can be suppressed, and the amount of Pt dissolved in the molten glass can be reduced. As a result, the coloration from Pt can be reduced.

＜其他成分組成＞ Pb、As、Cd、Tl、Be、Se皆具有毒性。因此，較佳為本實施形態的光學玻璃不含有此等元素作為玻璃成分。<Other component composition> Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferable that the optical glass of this embodiment does not contain these elements as a glass component.

U、Th、Ra皆為放射性元素。因此，較佳為本實施形態的光學玻璃不含有此等元素作為玻璃成分。U, Th, and Ra are all radioactive elements. Therefore, it is preferable that the optical glass of this embodiment does not contain these elements as a glass component.

V、Cr、Mn、Fe、Co、Ni、Cu、Pr，Nd、Pm、Sm、Eu、Tb、Dy、Ho、Er、Tm、Ce能增大玻璃的著色，成為螢光的發生源。因此，較佳為本實施形態的光學玻璃不含有此等元素作為玻璃成分。V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Ce can increase the color of the glass and become a source of fluorescence. Therefore, it is preferable that the optical glass of this embodiment does not contain these elements as a glass component.

硫酸鹽為發揮作為澄清劑功能之能任意地添加的氧化劑。硫酸鹽藉由加熱而分解生成澄清氣體SO₂ 及O₂ 。作為硫酸鹽沒有特別限定，但可舉出例如硫酸鋅、硫酸鋯等。Sulfate is an oxidant that can be arbitrarily added as a clarifier. Sulfate is decomposed by heating to produce clear gases SO ₂ and O ₂ . The sulfate is not particularly limited, and examples thereof include zinc sulfate and zirconium sulfate.

硫酸鹽的含量表示為外加比例。亦即，在將除硫酸鹽以外的全部玻璃成分的合計含量作為100質量%時之硫酸鹽的含量較佳為小於1質量%，更佳為小於0.5質量%，再佳為小於0.3質量%。硫酸鹽的含量亦可為0質量%。The sulfate content is expressed as an additive ratio. That is, when the total content of all glass components other than sulfate is 100% by mass, the content of sulfate is preferably less than 1% by mass, more preferably less than 0.5% by mass, and even more preferably less than 0.3% by mass. The content of sulfate may be 0% by mass.

Sb(Sb₂ O₃ )亦為發揮作為澄清劑功能之能任意地添加的元素。但是，Sb(Sb₂ O₃ )氧化性強，若增多添加量，則有促進來自鉑坩堝的鉑的氧化之虞。並且，在精密壓製成型時，玻璃所含的Sb(Sb₂ O₃ )將壓製成型模具的成型面進行氧化，因此在反復精密成型時，有成型面顯著劣化而無法精密壓製成型之虞。其結果，成型的光學元件的表面品質下降。因此，本實施形態之玻璃較佳為不含Sb(Sb₂ O₃ )。Sb (Sb ₂ O ₃ ) is also an element that can be arbitrarily added to exert its function as a clarifier. However, Sb (Sb ₂ O ₃ ) is highly oxidizing, and if the amount of Sb (Sb ₂ O ₃ ) is increased, the oxidation of platinum from a platinum crucible may be promoted. In addition, during precision press molding, Sb (Sb ₂ O ₃ ) contained in the glass oxidizes the molding surface of the press molding die. Therefore, when repeated precision molding is performed, the molding surface may be significantly deteriorated and precise press molding may not be performed. As a result, the surface quality of the molded optical element is reduced. Therefore, the glass of this embodiment is preferably free of Sb (Sb ₂ O ₃ ).

另外，本實施形態之玻璃，較佳為基本上由上述玻璃成分構成，但在不妨礙本發明的作用效果的範圍內，亦能含有其他的成分。並且，在本發明中，並不排除含有不可避免的雜質。In addition, the glass of this embodiment is preferably basically composed of the above-mentioned glass components, but may also contain other components within a range that does not impede the effects of the present invention. In addition, in the present invention, the inclusion of unavoidable impurities is not excluded.

(玻璃特性) ＜折射率nd＞在本實施形態之玻璃中，折射率nd較佳為1.75以上，再者，亦可為1.77以上、1.80以上。並且，折射率nd較佳為2.50以下，再者，亦可為2.20以下、2.10以下。折射率nd可藉由增加Nb₂ O₅ 、TiO₂ 、WO₃ 及Bi₂ O₃ 的合計含量[Nb₂ O₅ +TiO₂ +WO₃ +Bi₂ O₃ ]而提高，並且可藉由增加SiO₂ 的含量而降低。(Glass Characteristics) <Refractive Index nd> In the glass of this embodiment, the refractive index nd is preferably 1.75 or more, and may be 1.77 or more and 1.80 or more. The refractive index nd is preferably 2.50 or less, and may be 2.20 or less and 2.10 or less. The refractive index nd can be increased by increasing the total content of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ [Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ ], and can be increased by increasing The content of SiO ₂ decreases.

＜阿貝數νd＞在本實施形態之玻璃中，阿貝數νd為20以上。阿貝數νd亦可為20～45或21～45的範圍。阿貝數νd可藉由增加La₂ O₃ 的含量而提高，並且可藉由增加B₂ O₃ 的含量而降低。<Abbe number νd> In the glass of this embodiment, the Abbe number νd is 20 or more. The Abbe number νd may be in a range of 20 to 45 or 21 to 45. The Abbe number νd can be increased by increasing the content of La ₂ O ₃ , and can be decreased by increasing the content of B ₂ O ₃ .

＜玻璃的透光性＞在本實施形態之光學玻璃的透光性可藉由著色度λ70進行評價。針對厚度10.0mm±0.1mm的玻璃試樣，在波長200～700nm的範圍測定光譜透射率，將外部透射率成為70%的波長設為λ70。<Light Transmittance of Glass> The light transmittance of the optical glass in this embodiment can be evaluated by the degree of coloration λ70. With respect to a glass sample having a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured in a wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance was 70% was set to λ70.

本實施形態之光學玻璃的λ70較佳為480nm以下，更佳為470nm以下，再佳為450nm以下，特佳為440nm以下。λ70可藉由降低鉑Pt含量而降低。The λ70 of the optical glass of this embodiment is preferably 480 nm or less, more preferably 470 nm or less, even more preferably 450 nm or less, and particularly preferably 440 nm or less. λ70 can be reduced by reducing the platinum Pt content.

並且，本實施形態之光學玻璃的λ70較佳為滿足下述式(3)。 λ70≤a×b+373　···(3) 式(3)中，a較佳為200，進而依序更佳為195、190、185、180、175。並且，b為TiO₂ 的含量相對於B₂ O₃ 及La₂ O₃ 的合計含量之質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]。In addition, λ70 of the optical glass of this embodiment preferably satisfies the following formula (3). λ70≤a × b + 373 (3) In the formula (3), a is preferably 200, and then more preferably 195, 190, 185, 180, and 175 in that order. And, b is the content of TiO ₂ with respect to the mass of the total content of B ₂ O ₃ and La ₂ O ₃ ratio of _{_{[TiO 2 / (B 2 O}} 3 + La 2 O 3)].

若質量比[TiO₂ /(B₂ O₃ +La₂ O₃ )]增加，則可見短波長區域的透射率降低，著色度λ70增大。於本實施形態之光學玻璃，降低了還原色，可將λ70抑制在上述式(3)所示的範圍。When the mass ratio [TiO ₂ / (B ₂ O ₃ + La ₂ O ₃ )] is increased, it is seen that the transmittance in the short-wavelength region is decreased, and the degree of coloration λ70 is increased. In the optical glass of this embodiment, the reduction color is reduced, and λ70 can be suppressed within the range shown by the above formula (3).

＜T450＞本實施形態之光學玻璃的透光性可藉由T450進行評價。在本實施形態中，T450係換算成厚度10.0mm時的在波長450nm之外部透射率。所謂「外部透射率」係指針對經以具有相互平行且經光學拋光的平面之方式進行加工玻璃試樣，在經光學拋光的一個平面垂直地入射，透過玻璃的透射光的強度Iout相對於入射光的強度Iin之比(Iout/Iin)，亦即，亦考慮到玻璃的表面之表面反射的透射率。透射率能藉由使用分光光度計測定透射光譜而得到。此外，測定時的玻璃的厚度可為10.0mm，但在厚度不為10.0mm之情況中，亦可用習知的方法換算成厚度10.0mm之透射率。<T450> The light transmittance of the optical glass of this embodiment can be evaluated by T450. In this embodiment, T450 is converted to an external transmittance at a wavelength of 450 nm when the thickness is 10.0 mm. The so-called "external transmittance" refers to a pair of glass samples that have been processed in such a way that they have parallel and optically polished planes. They are incident perpendicularly on one of the optically polished planes. The intensity of the transmitted light transmitted through the glass is relative to the incidence. The ratio of the light intensity Iin (Iout / Iin), that is, the transmittance of the surface reflection of the surface of the glass is also taken into account. The transmittance can be obtained by measuring a transmission spectrum using a spectrophotometer. In addition, the thickness of the glass during the measurement may be 10.0 mm, but in the case where the thickness is not 10.0 mm, the transmittance may be converted to a thickness of 10.0 mm by a conventional method.

本實施形態之光學玻璃的T450較佳為65%以上，更佳為70%以上，進一步較佳為75%以上。T450可藉由降低玻璃的還原色而提高。The T450 of the optical glass of this embodiment is preferably 65% or more, more preferably 70% or more, and even more preferably 75% or more. T450 can be improved by reducing the reduction color of the glass.

＜T400＞本實施形態之光學玻璃的透光性亦可藉由T400進行評價。針對厚度為10.0mm±0.1mm的玻璃試樣，以分光光度計測定在波長400nm之外部透射率T400。亦可用習知的方法換算成厚度10.0mm之透射率。T400的值越大，意指透射率越優異，玻璃的著色越降低。<T400> The light transmittance of the optical glass of this embodiment can also be evaluated by T400. For a glass sample having a thickness of 10.0 mm ± 0.1 mm, the external transmittance T400 at a wavelength of 400 nm was measured with a spectrophotometer. It can also be converted into a transmittance with a thickness of 10.0 mm by a conventional method. The larger the value of T400, the better the transmittance, and the lower the coloration of the glass.

本實施形態之光學玻璃的T400較佳為50%以上，更佳為60%以上，再佳為70%以上。T400可藉由降低玻璃的還原色而提高。The T400 of the optical glass of this embodiment is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. T400 can be improved by reducing the reduction color of the glass.

＜τ400＞本實施形態之光學玻璃的透光性亦可藉由τ400進行評價。針對厚度為10.0mm±0.1mm的玻璃試樣，以分光光度計測定在波長400nm之內部透射率τ400。亦可用習知的方法換算成厚度10.0mm之透射率。τ400的值越大，意指透射率越優異，玻璃的著色越降低。<Τ400> The light transmittance of the optical glass of this embodiment can also be evaluated by τ400. For a glass sample having a thickness of 10.0 mm ± 0.1 mm, the internal transmittance τ400 at a wavelength of 400 nm was measured with a spectrophotometer. It can also be converted into a transmittance with a thickness of 10.0 mm by a conventional method. The larger the value of τ400 means that the more excellent the transmittance, the lower the coloration of the glass.

本實施形態之光學玻璃的τ400較佳為50%以上，更佳為60%以上，再佳為70%以上。τ400可藉由降低玻璃的還原色而提高。The τ400 of the optical glass of this embodiment is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. τ400 can be improved by reducing the reduction color of the glass.

＜玻璃的比重＞在本實施形態之玻璃中，比重較佳為7以下，進而依序更佳為6.5以下、6以下。並且，比重較佳為2.5以上，進而依序更佳為3以上、3.5以上。如可降低玻璃的比重，則可減少透鏡的重量。其結果，可降低搭載透鏡的攝影機鏡頭的自動對焦驅動的消耗電力。另一方面，若過度減少比重，則會導致熱穩定性下降。<Specific gravity of glass> In the glass of this embodiment, the specific gravity is preferably 7 or less, and more preferably 6.5 or less and 6 or less in order. In addition, the specific gravity is preferably 2.5 or more, and more preferably 3 or more and 3.5 or more in order. If the specific gravity of the glass can be reduced, the weight of the lens can be reduced. As a result, it is possible to reduce the power consumption of the autofocus driving of the camera lens equipped with the lens. On the other hand, if the specific gravity is excessively reduced, thermal stability will be reduced.

＜玻璃轉換溫度Tg＞本實施形態之光學玻璃的玻璃轉換溫度Tg較佳為800℃以下，進而依序更佳為770℃以下、750℃以下。並且，玻璃轉換溫度Tg較佳為300℃以上，進而依序更佳為350℃以上、400℃以上。玻璃轉換溫度Tg可藉由增加Li₂ O、Na₂ O及K₂ O的合計含量[Li₂ O+Na₂ O+K₂ O]而降低。<Glass transition temperature Tg> The glass transition temperature Tg of the optical glass of this embodiment is preferably 800 ° C or lower, and more preferably 770 ° C or lower and 750 ° C or lower in order. The glass transition temperature Tg is preferably 300 ° C or higher, and more preferably 350 ° C or higher and 400 ° C or higher in order. The glass transition temperature Tg can be decreased by increasing the total content of Li ₂ O, Na ₂ O, and K ₂ O [Li ₂ O + Na ₂ O + K ₂ O].

藉由玻璃轉換溫度Tg的上限滿足上述範圍，而可抑制玻璃的成型溫度及退火溫度的上升，可減輕對壓製成型用設備及退火設備的熱損傷。並且，藉由玻璃轉換溫度Tg的下限滿足上述範圍，而變得容易在維持期望的阿貝數、折射率的同時良好地維持玻璃的熱穩定性。When the upper limit of the glass transition temperature Tg satisfies the above range, it is possible to suppress an increase in the molding temperature and the annealing temperature of the glass, and it is possible to reduce thermal damage to the equipment for press molding and the annealing equipment. In addition, when the lower limit of the glass transition temperature Tg satisfies the above range, it becomes easy to maintain the desired thermal stability of the glass while maintaining the desired Abbe number and refractive index.

(光學玻璃的品質) 通常作為光學玻璃的缺點，有泡、渣滓(異物)、條紋。此等缺點的評價能藉由測定每單位量的玻璃中所含的缺點的多少而進行。阻礙透光性的比例會依據玻璃的每單位截面積的泡、渣滓的存在量而變化。(Quality of optical glass) Generally, defects of optical glass include bubbles, dross (foreign matter), and stripes. The evaluation of these defects can be performed by measuring the number of defects contained in the glass per unit amount. The proportion of blocking light transmission varies depending on the amount of bubbles and dross per unit cross-sectional area of the glass.

然而，在評價缺點的單位(評價單位)極小之情形，若選定不存在泡、渣滓的區域，則會成為該範圍中不存在光學缺點。但是，在作為通常使用的工業製品的光學玻璃中，不僅要求例如1mm×1mm般的微小範圍的均質性，亦要求例如100mm×100mm左右的截面積或具有規定以上的體積之玻璃的均質性。However, when the unit (evaluation unit) for evaluating defects is extremely small, if an area where bubbles and dross are not present is selected, there will be no optical defect in this range. However, the optical glass as a commonly used industrial product requires not only homogeneity in a minute range such as 1 mm × 1 mm, but also homogeneity in a cross-sectional area of about 100 mm × 100 mm or a glass having a predetermined volume or more.

而且，不僅評價單位，亦應該討論光學玻璃的生產單位。於製作1ml的玻璃之情形與製作1000kg的玻璃之情形，即使要求的均質性相同，製造的難易度亦為天壤之別。亦即，即使在使同一原料熔融、玻璃化之情形，需要的熱量亦會依據玻璃量而變化，例如即使為熔融溫度1250℃、熔融時間2小時的條件，在製作1ml的玻璃之情形可製作出沒有泡、渣滓的熔液(熔融玻璃)，相對於此，在製作1000kg的玻璃之情形甚至無法充分融解原料。Moreover, not only the evaluation unit, but also the production unit of the optical glass should be discussed. In the case of making 1ml of glass and the case of making 1000kg of glass, even if the required homogeneity is the same, the difficulty of production is very different. That is, even when the same raw material is melted and vitrified, the amount of heat required will vary depending on the amount of glass. For example, even if the melting temperature is 1250 ° C and the melting time is 2 hours, it can be produced in the case of 1ml glass On the other hand, in the case of producing 1000 kg of glass, molten material (melted glass) without bubbles and dross was produced, and the raw materials could not be melted sufficiently.

依據玻璃的量，不僅玻璃化所需要的條件會變化，脫泡(澄清)所需要的溫度、時間亦需要變化。若玻璃量增加，則玻璃化所需要的熱量增加，熔融時間、澄清時間亦變長。其結果，構成坩堝的鉑Pt在熔融玻璃中的溶出量增加。Depending on the amount of glass, not only the conditions required for vitrification will change, but also the temperature and time required for defoaming (clarification). When the amount of glass is increased, the heat required for vitrification is increased, and the melting time and clarification time also become longer. As a result, the elution amount of platinum Pt constituting the crucible in the molten glass increases.

亦即，在生產為工業製品的光學玻璃之情形，需要將玻璃容量設為規定以上，與實驗、小規模的玻璃製作比較，熔融條件、澄清條件、從生產裝置(坩堝等)混入到玻璃中的Pt的量亦會變化。That is, in the case of producing optical glass for industrial products, it is necessary to set the glass capacity to a predetermined level or more, compared with experiments and small-scale glass production, melting conditions, clarification conditions, and mixing into glass from production equipment (crucible, etc.) The amount of Pt will also change.

針對條紋，均質度更是重要的特性。所謂「條紋」的缺點，本來就是討論規定體積的光學均質性(空間的折射率分布)時的缺點，因此，評價單位自然需要為規定以上。即使在製作相同的1000ml的玻璃之情形，於一次製作1000ml的熔液之情形與製作100次10ml的玻璃熔液之情形，折射率的均一性亦不同。通常在製作光學玻璃之情形，一次製作1000ml的玻璃熔液可得到均質性優異的玻璃。For streaks, homogeneity is even more important. The so-called "stripe" disadvantage is originally a disadvantage when discussing the optical homogeneity (refractive index distribution in space) of a predetermined volume. Therefore, the evaluation unit naturally needs to be more than a predetermined value. Even in the case of making the same 1000 ml glass, the uniformity of the refractive index is different between the case of making a 1000 ml melt at one time and the case of making a 10 ml glass melt 100 times. In general, in the case of manufacturing optical glass, 1000 ml of glass melt can be produced at one time to obtain a glass having excellent homogeneity.

如以上般，作為工業製品處理的光學玻璃被針對在製作規定以上的容量之情形進行討論，在該範圍生產高品質的光學玻璃的困難度與對應於其製造方法的光學玻璃的特性、品質被密不可分地討論。As described above, the optical glass treated as an industrial product is discussed in the case of producing a predetermined capacity or more. The difficulty in producing high-quality optical glass in this range and the characteristics and quality of optical glass according to its manufacturing method are discussed. Discussed inextricably.

針對極小規模(例如小規模的實驗)的玻璃融解進行討論的技術，並非可直接適用於工業製品等級的玻璃融解者。而且，在玻璃製作規模不同之情形，無法一概地比較以各自的方法所製作之玻璃的特性、品質。The technology for discussing glass melting on a very small scale (such as a small-scale experiment) is not directly applicable to glass melting of industrial products. In addition, when the scale of glass production is different, it is impossible to compare the characteristics and quality of glass produced by the respective methods.

於本實施形態，為了區別此等實驗等級的玻璃的特性、品質與工業等級的玻璃的特性、品質，而導入所謂玻璃的均質度之概念。玻璃的均質度可藉由折射率分布而進行評價。In this embodiment, in order to distinguish the characteristics and quality of these experimental grade glasses from those of industrial grade glass, the concept of so-called glass homogeneity is introduced. The homogeneity of glass can be evaluated by the refractive index distribution.

＜折射率分布＞本實施形態之光學玻璃的折射率分布較佳為0.00050以內，再佳為0.00030以內，再佳為0.00010以內，再佳為0.00007以內，再佳為0.00005以內。折射率分布係針對具有100ml以上的玻璃體積的連續體進行測定。並且，折射率測定中使用的試樣的玻璃容量設為1ml以上。此外，玻璃的體積例如只要測定玻璃的質量，並根據測定結果與比重算出即可。<Refractive index profile> The refractive index profile of the optical glass of this embodiment is preferably within 0.00050, even more preferably within 0.00030, even more preferably within 0.00010, even more preferably within 0.00007, and even more preferably within 0.00005. The refractive index distribution is measured for a continuum having a glass volume of 100 ml or more. The glass capacity of the sample used for the refractive index measurement is 1 ml or more. The volume of the glass may be measured by, for example, the mass of the glass and calculated from the measurement result and the specific gravity.

具體而言，準備100ml以上的玻璃a，測定任意的位置A以及與A完全相對的位置B此二處的折射率。並且，如有已知折射率的部位，則將該部位設為A，測定距離A最遠的部位B的折射率。從玻璃a取得合計二處以上的玻璃片，進行折射率測定。於本實施形態，折射率分布的評價使用折射率nd進行，但亦可適當使用在其他波長之折射率進行評價。Specifically, 100 ml or more of glass a was prepared, and the refractive index at two positions: an arbitrary position A and a position B completely opposite to A was measured. In addition, if there is a part with a known refractive index, the part is set to A, and the refractive index of the part B farthest from A is measured. A total of two or more glass pieces were obtained from the glass a, and the refractive index was measured. In the present embodiment, the evaluation of the refractive index profile is performed using the refractive index nd, but the refractive index at other wavelengths may be appropriately used for the evaluation.

(光學玻璃的製造) 本發明的實施形態之光學玻璃，只要以成為上述規定的組成之方式調合玻璃原料，並使用調合的玻璃原料按照習知的玻璃製造方法進行製作即可。例如，調合多種化合物，充分混合而製成批料，並將批料置入鉑坩堝中進行粗融解(熔解步驟)。(Manufacture of Optical Glass) The optical glass according to the embodiment of the present invention may be prepared by blending glass raw materials so as to have the predetermined composition described above, and using the blended glass raw materials according to a known glass manufacturing method. For example, a plurality of compounds are blended and thoroughly mixed to prepare a batch, and the batch is put into a platinum crucible for rough melting (melting step).

在本實施形態之玻璃的融解步驟中，可在玻璃原料中添加還原劑。作為還原劑，沒有特別限定，但可舉出例如：Al、Si、Ti、W、H2、CO、C等表現還原性的物質。更具體而言，作為表現還原性的物質，可例示碳化合物、活性碳C。藉由在玻璃原料中添加還原劑，而在玻璃原料玻璃化時產生的反應活性高的氧與還原劑進行反應，抑制來自鉑坩堝的鉑的氧化反應。其結果，可降低玻璃中的Pt含量。In the melting step of the glass of this embodiment, a reducing agent may be added to the glass raw material. The reducing agent is not particularly limited, but examples thereof include those exhibiting reducing properties such as Al, Si, Ti, W, H2, CO, and C. More specifically, examples of the substance exhibiting reducing properties include carbon compounds and activated carbon C. By adding a reducing agent to the glass raw material, the highly reactive oxygen generated during the vitrification of the glass raw material reacts with the reducing agent, thereby suppressing the oxidation reaction of platinum from the platinum crucible. As a result, the Pt content in the glass can be reduced.

本實施形態之玻璃的融解步驟中之熔融氣體環境較佳為非氧化性氣體環境。藉由在非氧化氣體環境中進行融解步驟，而降低熔融氣體環境中的氧分壓，抑制來自鉑坩堝的鉑的氧化，而可降低熔融玻璃中溶入的Pt量。The molten gas environment in the melting step of the glass in this embodiment is preferably a non-oxidizing gas environment. By performing the melting step in a non-oxidizing gas environment, the oxygen partial pressure in the molten gas environment is reduced, the oxidation of platinum from the platinum crucible is suppressed, and the amount of Pt dissolved in the molten glass can be reduced.

作為非氧化性氣體環境沒有特別限定，但可舉出例如：氮、二氧化碳、氬、氦等非活性氣體氣體環境、附加水蒸氣的氣體環境。為了提高最終得到之玻璃的βOH，較佳為附加水蒸氣的氣體環境。The non-oxidizing gas environment is not particularly limited, but examples thereof include an inert gas gas environment such as nitrogen, carbon dioxide, argon, and helium, and a gas environment in which water vapor is added. In order to increase the βOH of the finally obtained glass, a gaseous environment with added water vapor is preferred.

藉由在熔融氣體環境中附加水蒸氣，而可提高最終得到之光學玻璃的βOH的值，並且可有效地防止Pt等溶入玻璃，且可對玻璃供給足以改善脫泡性及澄清性的溶存氣體。By adding water vapor to the molten gas environment, the βOH value of the finally obtained optical glass can be increased, and Pt and the like can be effectively prevented from dissolving into the glass, and the glass can be provided with a solution sufficient to improve defoaming and clarity. gas.

在熔融氣體環境中附加水蒸氣的方法沒有特別限定，但可舉出例如：從熔融裝置中設定的開口部將連結管***坩堝內，並依據需要經由此管向坩堝內的空間供給水蒸氣之方法等。The method of adding water vapor in a molten gas environment is not particularly limited, but examples include a method of inserting a connection tube into a crucible through an opening set in a melting device, and supplying water vapor to the space in the crucible through the tube as necessary Method, etc.

於融解步驟，以攪拌熔融物為目的，亦可伴隨鼓泡。融解時的鼓泡可在熔融調合材料後亦繼續進行。藉由在熔融步驟中攪拌熔融物，而進行玻璃成分的氧化，另一方面抑制來自鉑坩堝的鉑的氧化。其原因在於，玻璃成分有比鉑更容易被氧化的傾向。其結果，抑制玻璃成分的還原反應而降低還原色，並且抑制鉑溶入熔融物而亦降低來自鉑的著色。In the melting step, the purpose of stirring the melt may be accompanied by bubbling. Bubbling during melting can continue after the blending material is melted. By stirring the melt in the melting step, the glass component is oxidized, and the oxidation of platinum from the platinum crucible is suppressed. This is because glass components tend to be more easily oxidized than platinum. As a result, the reduction reaction of the glass component is suppressed to reduce the reduction color, and the dissolution of platinum into the melt is suppressed, and the coloration from platinum is also reduced.

用於鼓泡的氣體並無特別限定，可使用習知的氣體。可舉出例如：氮、二氧化碳、氬、氦等非活性氣體、空氣、以及包含水蒸氣之此等氣體。The gas used for bubbling is not particularly limited, and a conventional gas can be used. Examples thereof include inert gases such as nitrogen, carbon dioxide, argon, and helium; air; and gases containing water vapor.

藉由使用包含水蒸氣的氣體作為用於鼓泡的氣體，而可提高最終得到之光學玻璃的βOH的值，有效地防止鉑溶入玻璃中，且可對玻璃供給足以改善脫泡性及澄清性的溶存氣體。By using a gas containing water vapor as a gas for bubbling, the βOH value of the finally obtained optical glass can be increased, platinum can be effectively prevented from being dissolved in the glass, and the glass can be supplied sufficiently to improve defoaming and clarification Dissolved dissolved gas.

此種包含水蒸氣的氣體中之水蒸氣的含量較佳為10體積%以上，更佳為20體積%以上，再佳為30體積%以上，進而較佳為40體積%以上，進而更佳為50體積%以上，進而再佳為60體積%以上，再進而較佳為70體積%以上，特佳為80體積%以上，進而特佳為90體積%以上。水蒸氣的含量越高越佳，特別是藉由設為上述範圍，而可提高最終得到之光學玻璃的βOH的值。The content of water vapor in such a water vapor-containing gas is preferably 10 vol% or more, more preferably 20 vol% or more, even more preferably 30 vol% or more, still more preferably 40 vol% or more, and even more preferably It is 50% by volume or more, more preferably 60% by volume or more, still more preferably 70% by volume or more, particularly preferably 80% by volume or more, and even more preferably 90% by volume or more. The higher the water vapor content, the better, and particularly by setting the above range, the βOH value of the finally obtained optical glass can be increased.

將藉由粗融解而得到的熔融物進行急冷、粉碎，而製作碎玻璃。進而將碎玻璃置入鉑坩堝中，進行加熱、再熔融(remelt)而製成熔融玻璃，進一步進行澄清、均質化後，將熔融玻璃進行成型，緩慢冷卻而得到光學玻璃。熔融玻璃的成型、緩慢冷卻只要應用習知的方法即可。The molten material obtained by the coarse melting is quenched and pulverized to produce broken glass. The broken glass was further placed in a platinum crucible, and heated and remelted to prepare molten glass. After further clarification and homogenization, the molten glass was formed and slowly cooled to obtain an optical glass. The molding and slow cooling of the molten glass may be performed by a conventional method.

此外，如可將期望的玻璃成分以成為期望的含量之方式導入玻璃中，則在調合批料時使用的化合物沒有特別限定，但作為此種化合物，可舉出：氧化物、碳酸鹽、硝酸鹽、氫氧化物、氟化物等。In addition, if a desired glass component can be introduced into the glass so as to have a desired content, the compound used in preparing the batch is not particularly limited, but examples of such a compound include oxides, carbonates, and nitric acid Salt, hydroxide, fluoride, etc.

(光學元件等的製造) 為了使用本發明的實施形態之光學玻璃製作光學元件，只要應用習知的方法即可。例如，藉由將上述的熔融玻璃流入鑄模中而成型為板狀，製作由本發明的光學玻璃而成之玻璃素材。將所得到的玻璃素材適當進行切斷、研磨、拋光，製作適於壓製成型的大小、形狀的切片。(Manufacture of optical element, etc.) In order to produce an optical element using the optical glass of embodiment of this invention, what is necessary is just to apply a well-known method. For example, a glass material made of the optical glass of the present invention is produced by pouring the above-mentioned molten glass into a mold and forming it into a plate shape. The obtained glass material is appropriately cut, ground, and polished to produce a slice having a size and shape suitable for press molding.

將切片進行加熱、軟化，以習知的方法進行壓製成型(二次熱壓)，製作與光學元件的形狀近似的光學元件坯料。可將光學元件坯料進行退火，以習知的方法進行研磨、拋光，而製作光學元件。The slice is heated and softened, and press-molded (secondary hot-pressed) by a known method to produce an optical element blank having a shape similar to that of the optical element. The optical element blank can be annealed and ground and polished in a conventional manner to produce an optical element.

亦可將切片進行粗拋光加工(滾筒拋光)而將重量均等化，且使脫模劑容易附著在表面上，將進行再加熱而軟化的玻璃壓製成型為與期望的光學元件的形狀相近的形狀，最後進行研磨、拋光而製作光學元件。The slices can also be rough polished (roller polished) to equalize the weight, and the mold release agent can easily adhere to the surface, and the glass softened by reheating can be pressed into a shape close to the shape of the desired optical element. , And finally grinding and polishing to make optical elements.

或者，亦可將規定重量的熔融玻璃從成型模上分離而直接壓製成型，最後進行研磨及拋光而製造光學元件。Alternatively, a predetermined weight of molten glass may be separated from a molding die and directly pressed and molded, and finally polished and polished to manufacture an optical element.

在所製作之光學元件的光學功能面，亦可依據使用目的而塗覆抗反射膜、全反射膜等。 [實施例]On the optical functional surface of the produced optical element, an anti-reflection film, a total reflection film, etc. may also be applied depending on the purpose of use. [Example]

以下，藉由實施例而更詳細地說明本發明。但是，本發明並不受實施例中所示之態樣的限制。Hereinafter, the present invention will be described in more detail through examples. However, the present invention is not limited to the aspects shown in the examples.

以如下順序製作具有表1所示之玻璃組成的玻璃樣品，進行各種評價。A glass sample having the glass composition shown in Table 1 was produced in the following procedure, and various evaluations were performed.

[光學玻璃的製造] (實施例1-A) 首先，準備對應於玻璃的構成成分之氧化物、氫氧化物、碳酸鹽及硝酸鹽作為原材料，以所得到之光學玻璃的玻璃組成成為表1所示之各組成的方式，將上述原材料進行秤量、調合，並充分地混合原材料。將如此進行而得到的調合原料(批料)投入到鉑坩堝中，在1250℃～1400℃加熱2小時熔融而製成熔融玻璃(融解步驟)，在1300～1400℃攪拌1～2小時以期望均質化，並進行澄清(均質化•澄清步驟)。將熔融玻璃澆鑄到已預熱成適當溫度的模具中。將鑄入的玻璃在比玻璃轉換溫度Tg低100℃的溫度進行熱處理30分鐘，在爐內放置冷卻至室溫，藉此得到玻璃樣品。[Production of optical glass] (Example 1-A) First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of the glass were prepared as raw materials, and the glass composition of the obtained optical glass was shown in Table 1 With the composition shown, the above raw materials are weighed and blended, and the raw materials are sufficiently mixed. The blended raw material (batch) obtained in this way is put into a platinum crucible, heated at 1250 ° C to 1400 ° C for 2 hours and melted to make a molten glass (melting step), and stirred at 1300 to 1400 ° C for 1 to 2 hours. Homogenize and clarify (homogenization • clarification step). The molten glass is cast into a mold that has been preheated to the appropriate temperature. The cast glass was heat-treated at a temperature 100 ° C lower than the glass transition temperature Tg for 30 minutes, and left to cool to room temperature in a furnace to obtain a glass sample.

於融解步驟、均質化•澄清步驟，進行下述的操作。In the melting step, the homogenization and clarification steps, the following operations are performed.

將鉑製管從熔融爐外***到配置於爐內的鉑製坩堝內，經由此鉑製管，向鉑製坩堝內的空間供給水蒸氣。供給的水蒸氣的流量設為25cc/min。A platinum tube was inserted into the platinum crucible placed in the furnace from outside the melting furnace, and water vapor was supplied to the space inside the platinum crucible through the platinum tube. The flow rate of the supplied water vapor was set to 25 cc / min.

並且，經由上述鉑製管向鉑制坩堝內的空間供給氮，並且從設置於坩堝下部的管，在熔融物中用水蒸氣進行鼓泡。所供給的氮及水蒸氣的流量設為氮30L/min，水蒸氣0.1cc/min。In addition, nitrogen is supplied to the space inside the platinum crucible through the platinum tube, and water vapor is bubbled into the molten material from a tube provided at the lower portion of the crucible. The flow rate of the supplied nitrogen and water vapor was set to 30 L / min of nitrogen and 0.1 cc / min of water vapor.

進而，將添加材料的有無、融解步驟及均質化•澄清步驟的條件如表2～4所示般進行變更，製作玻璃樣品。具體而言如下所述。Furthermore, the presence or absence of an additive, the melting step, and the conditions of the homogenization and clarification step were changed as shown in Tables 2-4, and glass samples were produced. Specifically, it is as follows.

(實施例1-B) 將對應於表1所記載之No.1的調合原料與表2所示之添加材料一起投入到鉑坩堝中，以表2所示之條件1-1～條件1-9的各條件進行加熱、熔融而製成熔融玻璃(融解步驟)，進行攪拌以期望均質化並進行澄清(均質化•澄清步驟)，除此以外，與實施例1-A同樣地得到玻璃樣品。(Example 1-B) The blending materials corresponding to No. 1 described in Table 1 were added to a platinum crucible together with the additive materials shown in Table 2, and conditions 1-1 to 1- Each of the conditions of 9 was heated and melted to prepare a molten glass (melting step), and stirring was performed to expect homogenization and clarification (homogenization and clarification step), except that a glass sample was obtained in the same manner as in Example 1-A. .

(實施例1-C) 將對應於表1所記載之No.2的調合原料與表3所示之添加材料一起投入到鉑坩堝中，以表3所示之條件2-1～條件2-4的各條件進行加熱、熔融而製成熔融玻璃(融解步驟)，進行攪拌以期望均質化並進行澄清(均質化•澄清步驟)，除此以外，與實施例1-A同樣地得到玻璃樣品。(Example 1-C) A blending material corresponding to No. 2 described in Table 1 was added to a platinum crucible together with the additive materials shown in Table 3, and conditions 2-1 to 2 shown in Table 3 were used. Each condition of 4 was heated and melted to prepare a molten glass (melting step), and stirring was performed to expect homogenization and clarification (homogenization and clarification step), except that a glass sample was obtained in the same manner as in Example 1-A. .

(實施例1-D) 將對應於表1所記載之No.4的調合原料與表4所示之添加材料一起投入到鉑坩堝中，以表4所示之條件4-1～條件4-5的各條件進行加熱、熔融而製成熔融玻璃(融解步驟)，進行攪拌以期望均質化並進行澄清(均質化•澄清步驟)，除此以外，與實施例1-A同樣地得到玻璃樣品。(Example 1-D) The blending materials corresponding to No. 4 described in Table 1 were added to a platinum crucible together with the additive materials shown in Table 4, and the conditions 4-1 to 4 shown in Table 4 were used. Each condition of 5 was heated and melted to prepare a molten glass (melting step), and stirring was performed to expect homogenization and clarification (homogenization and clarification step), except that a glass sample was obtained in the same manner as in Example 1-A. .

[玻璃成分組成的確認] 針對所得到之玻璃樣品，以感應耦合電漿原子發射光譜儀(ICP-AES)測定各玻璃成分的含量，確認為如表1所示之各組成。[Confirmation of glass component composition] About the obtained glass sample, the content of each glass component was measured with an inductively coupled plasma atomic emission spectrometer (ICP-AES), and it was confirmed that each composition was as shown in Table 1.

[玻璃中的Pt量的測定] 利用感應耦合電漿質譜儀(ICP-MS)，將玻璃中的鉑Pt的含量進行定量。將定量結果揭示於表1～4。[Measurement of Pt Amount in Glass] The content of platinum Pt in glass was quantified by an inductively coupled plasma mass spectrometer (ICP-MS). The quantitative results are shown in Tables 1 to 4.

[脫泡•澄清效果的確認] 針對所得到之玻璃樣品，計數玻璃內部所觀察到的氣泡數量，算出每單位質量(kg)所含之氣泡(殘留泡)的數量。將計算結果揭示於表2～4。[Confirmation of defoaming and clarification effects] With respect to the obtained glass sample, the number of bubbles observed inside the glass was counted, and the number of bubbles (residual bubbles) per unit mass (kg) was calculated. The calculation results are shown in Tables 2 to 4.

[光學特性的測定] 針對所得到之玻璃樣品，測定βOH、λ70、T400及T450。並且，將所得到之玻璃樣品進一步在710℃退火處理72小時後，在爐內以降溫速度-30℃/小時冷卻至室溫，製作退火樣品，測定折射率nd、ng、nF及nC、阿貝數νd、λ70及T400。[Measurement of Optical Properties] About the obtained glass samples, βOH, λ70, T400 and T450 were measured. Furthermore, the obtained glass sample was further annealed at 710 ° C for 72 hours, and then cooled to a room temperature at a temperature lowering rate of -30 ° C / hour in a furnace to prepare an annealed sample, and the refractive indices nd, ng, nF, nC, and Ah were measured. Shell number νd, λ70 and T400.

(i)折射率nd、ng、nF、nC及阿貝數νd 針對上述退火樣品，藉由JIS標準JIS B7071-1的折射率測定法，測定折射率nd、ng、nF、nC，並基於式(1)計算阿貝數νd。將結果揭示於表1。 νd=(nd-1)/(nF-nC) 　···(1)(i) Refractive index nd, ng, nF, nC, and Abbe number νd The refractive index nd, ng, nF, and nC of the annealed sample were measured by the refractive index measurement method of JIS standard JIS B7071-1. (1) Calculate the Abbe number νd. The results are shown in Table 1. νd = (nd-1) / (nF-nC) ... (1)

(ii)βOH 將上述玻璃樣品加工成厚度為1mm之具有相互平行且經光學拋光的平面之板狀玻璃試樣。在此板狀玻璃試樣的拋光面從垂直方向入射光，使用分光光度計分別測定在波長2500nm之外部透射率A及在波長2900nm之外部透射率B，藉由下述式(2)算出βOH。將結果揭示於表1～4。 βOH＝-[ln(B/A)]/t　··· (2)(ii) βOH The above-mentioned glass sample was processed into a plate-shaped glass sample having a thickness of 1 mm and having mutually parallel and optically polished planes. Light was incident on the polished surface of this plate-shaped glass sample from a vertical direction, and the external transmittance A at a wavelength of 2500 nm and the external transmittance B at a wavelength of 2900 nm were measured using a spectrophotometer, and βOH was calculated by the following formula (2) . The results are shown in Tables 1 to 4. βOH =-[ln (B / A)] / t ·· (2)

上述式(2)中，ln為自然對數，厚度t相當於上述二個平面的間隔。並且，外部透射率也包含在玻璃試樣表面的反射損耗，為透射光的強度相對於入射到玻璃試樣的入射光的強度之比(透射光強度/入射光強度)。In the above formula (2), ln is a natural logarithm, and the thickness t corresponds to the interval between the two planes. The external transmittance also includes reflection loss on the surface of the glass sample, and is the ratio of the intensity of transmitted light to the intensity of incident light incident on the glass sample (transmitted light intensity / incident light intensity).

(iii)λ70 將實施例1-A所得到的玻璃樣品，以厚度為10mm、具有相互平行且經光學拋光的平面之方式進行加工，測量在從波長280nm至700nm為止的波長區域之光譜透射率。將在經光學拋光的一個平面垂直入射之光線的強度設為強度A，將從另一個平面出射之光線的強度設為強度B，算出光譜透射率B/A。將光譜透射率成為70%的波長設為λ70。此外，光譜透射率中亦包含在試料表面之光線的反射損耗。將結果揭示於表1。(iii) λ70 The glass sample obtained in Example 1-A was processed to have a thickness of 10 mm and a plane parallel to each other and optically polished, and measured the spectral transmittance in a wavelength range from 280 nm to 700 nm . The intensity of the light incident perpendicularly on one plane subjected to optical polishing is referred to as the intensity A, and the intensity of the light emitted from the other plane is referred to as the intensity B, and the spectral transmittance B / A is calculated. The wavelength at which the spectral transmittance is 70% is λ70. In addition, the spectral transmittance also includes the reflection loss of light on the sample surface. The results are shown in Table 1.

針對實施例1-B～1-D所得到之玻璃樣品，與上述同樣地測定退火處理前(熱處理前)及退火處理後(熱處理後)的λ70。在表2～4中，揭示退火處理前(熱處理前)及退火處理後(熱處理後)的λ70。For the glass samples obtained in Examples 1-B to 1-D, λ70 before the annealing treatment (before the heat treatment) and after the annealing treatment (after the heat treatment) were measured in the same manner as described above. Tables 2 to 4 show λ70 before the annealing treatment (before the heat treatment) and after the annealing treatment (after the heat treatment).

(iv)T400 針對實施例1-B所得到之玻璃樣品，測定退火處理前(熱處理前)及退火處理後(熱處理後)的T400。具體而言，將玻璃樣品或退火樣品，以厚度為10mm、具有相互平行且經光學拋光的平面之方式進行加工，測量在波長400nm之光譜透射率。此外，光譜透射率中亦包含在試樣表面之光線的反射損耗。表2中，揭示在退火處理前(熱處理前)及退火處理後(熱處理後)之T400。(iv) T400 For the glass sample obtained in Example 1-B, T400 was measured before the annealing treatment (before the heat treatment) and after the annealing treatment (the heat treatment). Specifically, a glass sample or an annealed sample was processed to have a thickness of 10 mm, having planes parallel to each other and optically polished, and a spectral transmittance at a wavelength of 400 nm was measured. In addition, the spectral transmittance also includes the reflection loss of light on the sample surface. Table 2 shows T400 before the annealing treatment (before the heat treatment) and after the annealing treatment (the heat treatment).

(v)T450 將實施例1-A所得到之玻璃樣品，以厚度為10mm、具有相互平行且經光學拋光的平面之方式進行加工，測量在波長450nm之光譜透射率。此外，光譜透射率中亦包含在試樣表面之光線的反射損耗。將結果揭示於表1。(v) T450 The glass sample obtained in Example 1-A was processed to have a thickness of 10 mm, having mutually parallel and optically polished planes, and measuring the spectral transmittance at a wavelength of 450 nm. In addition, the spectral transmittance also includes the reflection loss of light on the sample surface. The results are shown in Table 1.

[表1] [Table 1]

[表2] [Table 2]

[表3] [table 3]

[表4] [Table 4]

根據表1的結果，在熔融氣體環境中導入水蒸氣、或在熔融玻璃中用水蒸氣進行鼓泡而提高βOH的值的結果，可得到著色少、在波長450nm之光譜透射率高的光學玻璃。Based on the results in Table 1, as a result of increasing the value of βOH by introducing water vapor in a molten gas environment or bubbling water vapor in a molten glass, optical glass with less coloration and high spectral transmittance at a wavelength of 450 nm was obtained.

根據表2～4的結果可知，藉由提高玻璃的βOH的值，而在玻璃成型後，能在未於氧化性氣體環境中進行長時間加熱處理之情況下，得到著色少、可見區域的透射率高的光學玻璃。From the results in Tables 2 to 4, it can be seen that by increasing the βOH value of the glass, after the glass is molded, it is possible to obtain transmission in the visible region with less coloring without long-term heat treatment in an oxidizing gas environment. High rate of optical glass.

(實施例2) 製作由具有表1所示之No.1的組成且藉由表2的條件1-1所製作之玻璃而成的15mm×175mm×1500mm的玻璃塊，將其切斷而進行5等分，取得5個15mm×175mm×300mm的玻璃塊。使用5等分的各玻璃塊製作5個折射率測定用試樣1~5，測定各試樣的折射率nd。以位於切斷前的二個端部中之一者的試樣1的折射率為基準，試樣2～5的折射率分布如下所述。(Example 2) A 15 mm × 175 mm × 1500 mm glass block made of glass having a composition of No. 1 shown in Table 1 and produced under conditions 1-1 of Table 2 was produced, and cut to perform Five equal parts were obtained, and five pieces of glass of 15 mm × 175 mm × 300 mm were obtained. Five samples 1 to 5 for refractive index measurement were prepared using each of the five glass blocks, and the refractive index nd of each sample was measured. The refractive index distributions of samples 2 to 5 based on the refractive index of sample 1 located at one of the two end portions before cutting are as follows.

從與試樣1相鄰的部位採取的試樣2的折射率nd與試樣1的折射率nd的差為+0.00001，從中央部採取的試樣3的折射率nd與試樣1的折射率nd的差為+0.00002，從與試樣3相鄰的部位採取的試樣4的折射率與試樣1的折射率的差為0.00000，從切斷前的二個端部中的與試樣1的完全相對的端部採取的試樣5的折射率與試樣1的折射率的差為-0.00003。如以上般，5處的折射率分布為0.00005。The difference between the refractive index nd of the sample 2 taken from the portion adjacent to the sample 1 and the refractive index nd of the sample 1 is +0.00001, and the refractive index nd of the sample 3 taken from the center and the refraction of the sample 1 The difference in the rate nd is +0.00002, the difference between the refractive index of the sample 4 taken from a portion adjacent to the sample 3 and the refractive index of the sample 1 is 0.00000. The difference between the refractive index of sample 5 and the refractive index of sample 1 taken at the completely opposite ends of sample 1 was -0.00003. As described above, the refractive index distribution at five places is 0.00005.

用同樣的方法對具有表1所示的No.1的組成且根據表2的條件1-2～條件1-9而製作的玻璃測定折射率分布，結果5處的折射率分布為0.00005以內。The refractive index distribution of the glass having the composition shown in Table 1 with No. 1 shown in Table 1 and the conditions 1-2 to 1-9 of Table 2 was measured in the same manner. As a result, the refractive index distribution at 5 places was within 0.00005.

進而，用同樣的方法亦對具有表1所示的No.2～17的各組成且根據實施例1-A的條件而製作的玻璃測定折射率分布，結果5處的折射率分布為0.00005以內。Furthermore, the refractive index distribution of the glass having the compositions of Nos. 2 to 17 shown in Table 1 and prepared under the conditions of Example 1-A was measured by the same method. As a result, the refractive index distribution at 5 places was within 0.00005. .

(實施例3) 使用在實施例1-A～1-D中製作的各光學玻璃，藉由習知的方法製作透鏡坯料，將透鏡坯料藉由拋光等習知的方法進行加工而製作各種透鏡。製作的光學透鏡為雙凸透鏡、雙凹透鏡、平凸透鏡、平凹透鏡、凹彎月透鏡、凸彎月透鏡等各種透鏡。各種透鏡藉由與由其他種類的光學玻璃而成之透鏡組合，而可良好地校正二次的色像差。(Example 3) Using each optical glass produced in Examples 1-A to 1-D, a lens blank was produced by a conventional method, and the lens blank was processed by a conventional method such as polishing to produce various lenses. . The produced optical lenses are various lenses such as biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, concave meniscus lenses, and convex meniscus lenses. By combining various lenses with lenses made of other types of optical glass, secondary chromatic aberrations can be corrected well.

並且，由於玻璃為低比重，因此比與各透鏡具有同等的光學特性、大小的透鏡的重量小，適合用於各種攝影設備，特別是由於能節能的理由等而適合用於自動對焦式的攝影設備。同樣地進行，使用在實施例1-A～1-D製作的各種光學玻璃製作棱鏡。In addition, because glass has a low specific gravity, it has a smaller weight than lenses that have the same optical characteristics and size as each lens, and is suitable for use in a variety of photographic equipment. In particular, it is suitable for autofocus photography due to energy saving reasons. device. In the same manner, prisms were produced using various optical glasses produced in Examples 1-A to 1-D.

應當認為本發明揭露的實施方式在所有方面皆為例示而並非限制性的。本發明的範圍不是藉由上述的說明而是藉由申請專利範圍而表示，意在包含與申請專利範圍等同的含義及範圍內的全部變更。It should be understood that the embodiments disclosed in the present invention are illustrative and not restrictive in all aspects. The scope of the present invention is indicated not by the above description but by the scope of patent application, and is intended to include all modifications within the meaning and scope equivalent to the scope of patent application.

例如，對於上述例示的玻璃組成，進行說明書中記載的組成調節，藉此可製作本發明的一態樣之光學玻璃。並且，當然能將作為說明書中例示或較佳的範圍中記載的二個以上的事項任意組合。For example, by adjusting the composition of the glass exemplified above as described in the specification, the optical glass of one aspect of the present invention can be produced. In addition, it is needless to say that two or more matters described in the scope of the description or preferable in the specification can be arbitrarily combined.

無。no.

Claims

一種光學玻璃，其包含3~45質量%的B₂O₃、20~60質量%的La₂O₃，包含選自由TiO₂、Nb₂O₅、WO₃及Bi₂O₃而成之群組中的至少一個氧化物，P₂O₅的含量為2質量%以下，下述式(2)所示的βOH的值為0.1~2.0mm^-1，βOH=-[ln(B/A)]/t…(2)式(2)中，t表示外部透射率的測定中使用的該光學玻璃的厚度(mm)，A表示對該光學玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對該光學玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)，並且ln為自然對數。An optical glass comprising 3 to 45% by mass of B ₂ O ₃ and 20 to 60% by mass of La ₂ O ₃ , and comprising a group selected from the group consisting of TiO ₂ , Nb ₂ O ₅ , WO ₃ and Bi ₂ O ₃ The content of P ₂ O ₅ of at least one oxide in the group is 2% by mass or less. The value of βOH represented by the following formula (2) is 0.1 to 2.0 mm ^-1 , and βOH =-[ln (B / A) ] / t ... (2) In formula (2), t represents the thickness (mm) of the optical glass used in the measurement of external transmittance, and A represents the wavelength at which the optical glass is incident with light parallel to its thickness direction. The external transmittance (%) at 2500 nm, B represents the external transmittance (%) at a wavelength of 2900 nm when light is incident on the optical glass parallel to its thickness direction, and ln is a natural logarithm.

如申請專利範圍第1項所述之光學玻璃，其中，包含0.1~25質量%的SiO₂。The optical glass according to item 1 of the patent application scope, which contains 0.1 to 25% by mass of SiO ₂ .

如申請專利範圍第1項所述之光學玻璃，其中，包含0.5~15質量%的SiO₂、3~30質量%的B₂O₃、20~60質量%的La₂O₃。The optical glass according to item 1 of the scope of patent application, which contains 0.5 to 15% by mass of SiO ₂ , 3 to 30% by mass of B ₂ O ₃ , and 20 to 60% by mass of La ₂ O ₃ .

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，以質量%表示，B₂O₃的含量大於SiO₂的含量。The optical glass according to any one of claims 1 to 3 in the scope of patent application, wherein the content of B ₂ O ₃ is greater than the content of SiO ₂ in terms of mass%.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，TiO₂的含量相對於B₂O₃及La₂O₃的合計含量之質量比[TiO₂/(B₂O₃+La₂O₃)]為0.030以上。Patent application range as 1 to 3 of the optical glass according to any one, wherein, TiO ₂ content with respect to the mass of the total content of B ₂ O ₃ and La ₂ O ₃ ratio of [TiO _₂ / (B ₂ O ₃ + La ₂ O ₃ )] is 0.030 or more.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，阿貝數νd為20~45，折射率nd為1.75~2.50。The optical glass according to any one of claims 1 to 3, wherein the Abbe number νd is 20 to 45 and the refractive index nd is 1.75 to 2.50.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，Nb₂O₅及TiO₂的合計含量為13質量%以上。The optical glass according to any one of claims 1 to 3, wherein the total content of Nb ₂ O ₅ and TiO ₂ is 13% by mass or more.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，Nb₂O₅及TiO₂的合計含量為40質量%以下。The optical glass according to any one of claims 1 to 3, wherein the total content of Nb ₂ O ₅ and TiO ₂ is 40% by mass or less.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，Nb₂O₅、TiO₂、WO₃及Bi₂O₃的合計含量為40質量%以下。The optical glass according to any one of claims 1 to 3, wherein the total content of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ is 40% by mass or less.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，Nb₂O₅、TiO₂、WO₃及Bi₂O₃的合計含量為1.0質量%以上。The optical glass according to any one of claims 1 to 3, wherein the total content of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ is 1.0% by mass or more.

如申請專利範圍第1至3項中任一項所述之光學玻璃，其中，B₂O₃、La₂O₃、SiO₂、P₂O₅、Al₂O₃、ZnO、BaO、MgO、CaO、SrO、Gd₂O₃、Y₂O₃、Yb₂O₃、ZrO₂、TiO₂、Nb₂O₅、WO₃、Bi₂O₃、Ta₂O₅、Li₂O、Na₂O、K₂O、Cs₂O、Sc₂O₃、HfO₂、Lu₂O₃及GeO₂的合計含量為大於95質量%。The optical glass according to any one of claims 1 to 3, wherein B ₂ O ₃ , La ₂ O ₃ , SiO ₂ , P ₂ O ₅ , Al ₂ O ₃ , ZnO, BaO, MgO, CaO, SrO, Gd ₂ O ₃ , Y ₂ O ₃ , Yb ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , Li ₂ O, Na ₂ O _{_{, K 2 O, Cs 2 O}} , Sc 2 O 3, HfO 2, Lu 2 O 3 and GeO ₂ is more than the total content of 95% by mass.

一種光學玻璃，其包含3~45質量%的B₂O₃、20~60質量%的La₂O₃、超過0質量%的TiO₂、超過0質量%的ZnO，TiO₂的含量相對於Nb₂O₅、TiO₂、WO₃及Bi₂O₃的合計含量之質量比[TiO₂/(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)]為0.4以上，P₂O₅的含量為2質量%以下，下述式(2)所示的βOH的值為0.1~2.0mm^-1，βOH=-[ln(B/A)]/t…(2)式(2)中，t表示外部透射率的測定中使用的該光學玻璃的厚度(mm)，A表示對該光學玻璃以與其厚度方向平行地入射光時的在波長2500nm之外部透射率(%)，B表示對該光學玻璃以與其厚度方向平行地入射光時的在波長2900nm之外部透射率(%)，並且ln為自然對數。An optical glass comprising 3 to 45% by mass of B ₂ O ₃ , 20 to 60% by mass of La ₂ O ₃ , more than 0% by mass of TiO ₂ , and more than 0% by mass of ZnO, and the content of TiO ₂ is relative to Nb The mass ratio of the total content of ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ [TiO ₂ / (Nb ₂ O ₅ + TiO ₂ + WO ₃ + Bi ₂ O ₃ )] is 0.4 or more, and P ₂ O ₅ The content of βOH is 2% by mass or less. The value of βOH represented by the following formula (2) is 0.1 to 2.0 mm ^-1 , and βOH =-[ln (B / A)] / t (2) In formula (2) , T represents the thickness (mm) of the optical glass used in the measurement of external transmittance, A represents the external transmittance (%) at a wavelength of 2500 nm when light is incident on the optical glass parallel to its thickness direction, and B represents the This optical glass has an external transmittance (%) at a wavelength of 2900 nm when light is incident parallel to its thickness direction, and ln is a natural logarithm.

如申請專利範圍第1至3、12項中任一項所述之光學玻璃，其中，鉑Pt的含量為小於10質量ppm。The optical glass according to any one of claims 1 to 3 and 12, in which the content of platinum Pt is less than 10 mass ppm.

如申請專利範圍第1至3、12項中任一項所述之光學玻璃，其中，體積為100ml以上，折射率分布為0.00050以內。The optical glass according to any one of claims 1 to 3 and 12, wherein the volume is 100 ml or more and the refractive index distribution is within 0.00050.

一種光學元件，其係由如申請專利範圍第1至14項中任一項所述之光學玻璃而成。An optical element is made of the optical glass according to any one of claims 1 to 14 of the scope of patent application.