TWI789340B

TWI789340B - Optical glass, preforms and optical components

Info

Publication number: TWI789340B
Application number: TW105136782A
Authority: TW
Inventors: 吉川健; 永岡敦
Original assignee: 日商小原股份有限公司
Priority date: 2015-11-11
Filing date: 2016-11-11
Publication date: 2023-01-11
Also published as: TW201718421A; TW202313501A; CN106927674A

Abstract

本發明之課題在於獲得一種折射率(n_d )及阿貝數(ν_d )處於所需之範圍內，並且部分分散比(θg，F)較小之光學玻璃。本發明之光學玻璃以質量%計而含有10.0～70.0%之SiO₂ 成分、1.0～50.0%之Nb₂ O₅ 成分及1.0～30.0%之Na₂ O成分，且具有1.62以上且1.75以下之折射率(n_d )、30以上且42以下之阿貝數(ν_d )、及0.594以下之部分分散比(θg，F)。The object of the present invention is to obtain an optical glass whose refractive index ( _nd ) and Abbe number (ν _d ) are within the desired range, and whose partial dispersion ratio (θg, F) is small. The optical glass of the present invention contains 10.0-70.0% of SiO ₂ components, 1.0-50.0% of Nb ₂ O ₅ components and 1.0-30.0% of Na ₂ O components in terms of mass %, and has a refraction of 1.62 to 1.75 Ratio (n _d ), Abbe number (ν _d ) of 30 or more and 42 or less, and partial dispersion ratio (θg, F) of 0.594 or less.

Description

Optical glass, preforms and optical components

本發明係關於一種光學玻璃、預成形體及光學元件。The invention relates to an optical glass, a preform and an optical element.

數位相機或攝錄影機等光學系統雖然其大小不同，但含有被稱為像差之模糊。該像差係被分類為單色像差與色像差，尤其是色像差較強地取決於光學系統中所使用之透鏡之材料特性。通常，色像差係將低分散之凸透鏡與高分散之凹透鏡組合而進行修正，但該組合僅可修正紅色範圍與綠色範圍之像差，而殘留藍色範圍之像差。將該無法完全去除之藍色範圍之像差稱為二次光譜。為了修正二次光譜，必須進行加入有藍色範圍之g射線(435.835 nm)之動向之光學設計。此時，作為光學設計中著眼之光學特性之指標，使用部分分散比(θg，F)。於將上述之低分散之透鏡與高分散之透鏡組合之光學系統中，藉由於低分散側之透鏡中使用部分分散比(θg，F)較大之光學材料，於高分散側之透鏡中使用部分分散比(θg，F)較小之光學材料，而良好地修正二次光譜。部分分散比(θg，F)係藉由下式(1)而表示。 θg，F＝(n_g －n_F )/(n_F －n_C )・・・・・・(1) 於光學玻璃中，於表示短波長範圍之部分分散性之部分分散比(θg，F)與阿貝數(ν_d )之間，存在大致直線之關係。表示該關係之直線係於採用部分分散比(θg，F)作為縱軸、採用阿貝數(ν_d )作為橫軸之正交座標上，以將對NSL7與PBM2之部分分散比及阿貝數進行繪圖而成之兩點連結之直線表示，被稱為標準線(參照圖1)。成為標準線之基準之標準玻璃雖依每個光學玻璃製造商而不同，但各公司均係以基本同等之斜率與截距進行定義。(NSL7與PBM2係OHARA股份有限公司製造之光學玻璃，PBM2之阿貝數(ν_d )為36.3，部分分散比(θg，F)為0.5828，NSL7之阿貝數(ν_d )為60.5，部分分散比(θg，F)為0.5436) 此處，作為具有30以上且42以下之阿貝數(νd)之玻璃，例如已知有專利文獻1、2中所示般之光學玻璃。 [先前技術文獻] [專利文獻] [專利文獻1]日本專利特開2002-029777號公報 [專利文獻2]日本專利特開2008-239478號公報Optical systems such as digital cameras or camcorders contain blurring called aberrations, although they vary in size. This aberration is classified into monochromatic aberration and chromatic aberration, especially chromatic aberration strongly depends on the material properties of the lens used in the optical system. Usually, chromatic aberration is corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but this combination can only correct the aberrations in the red and green ranges, leaving the aberrations in the blue range. The aberration in the blue range that cannot be completely removed is called secondary spectrum. In order to correct the secondary spectrum, it is necessary to perform an optical design that incorporates the movement of g-rays (435.835 nm) in the blue range. At this time, the partial dispersion ratio (θg, F) is used as an index of the optical characteristics to be focused on in the optical design. In the optical system that combines the above-mentioned low-dispersion lens and high-dispersion lens, by using an optical material with a larger partial dispersion ratio (θg, F) in the lens on the low-dispersion side, it can be used in the lens on the high-dispersion side The optical material with a small partial dispersion ratio (θg, F) can correct the secondary spectrum well. The partial dispersion ratio (θg, F) is represented by the following formula (1). θg, F=(n _g -n _F )/(n _F -n _C )・・・・・・・(1) In optical glass, the partial dispersion ratio (θg, F ) and the Abbe number (ν _d ), there is a roughly linear relationship. The straight line representing this relationship is on the orthogonal coordinates using the partial dispersion ratio (θg, F) as the vertical axis and the Abbe number (ν _d ) as the horizontal axis, so as to compare the partial dispersion ratio and the Abbe number of NSL7 and PBM2 The straight line representing the connection of two points obtained by plotting the number is called the standard line (refer to Figure 1). The standard glass used as the benchmark of the standard line is different for each optical glass manufacturer, but each company defines it with basically the same slope and intercept. (NSL7 and PBM2 are optical glasses manufactured by OHARA Co., Ltd., the Abbe number (ν _d ) of PBM2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν _d ) of NSL7 is 60.5. Dispersion ratio (θg, F) is 0.5436) Here, as glass having an Abbe's number (νd) of 30 or more and 42 or less, for example, optical glasses shown in Patent Documents 1 and 2 are known. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2002-029777 [Patent Document 2] Japanese Patent Laid-Open No. 2008-239478

[發明所欲解決之問題] 然而，專利文獻1中所揭示之玻璃之部分分散比不小，不足以用作修正上述二次光譜之透鏡。又，專利文獻2中所揭示之玻璃雖然具有相對較小之部分分散比，但阿貝數較大，故而需求阿貝數更小之玻璃。本發明係鑒於上述問題點而成者，其目的在於獲得一種折射率(n_d )及阿貝數(ν_d )處於所需之範圍內、並且部分分散比(θg，F)較小之光學玻璃。 [解決問題之技術手段] 本發明者等人為了解決上述課題而反覆努力試驗研究，結果發現，於含有SiO₂ 成分及Nb₂ O₅ 成分之玻璃中，可獲得具有所需範圍內之較高之折射率或較低之阿貝數(較高之分散)、與較低之部分分散比之玻璃，從而完成了本發明。具體而言，本發明係提供如下者。 (1)一種光學玻璃，其以質量%計而含有 10.0～70.0%之SiO₂ 成分、 1.0～50.0%之Nb₂ O₅ 成分、及 1.0～30.0%之Na₂ O成分，且具有 1.62以上且1.75以下之折射率(n_d )、 30以上且42以下之阿貝數(ν_d )、及 0.594以下之部分分散比(θg，F)。 (2)如(1)記載之光學玻璃，其中以質量%計，B₂ O₃ 成分之含量為25.0%以下。 (3)如(1)或(2)記載之光學玻璃，其中質量比(Li₂ O＋Na₂ O)/(ZrO₂ )為0.50以上。 (4)如(1)至(3)中任一項記載之光學玻璃，其中以質量%計，Li₂ O成分之含量為20.0%以下。 (5)如(1)至(4)中任一項記載之光學玻璃，其中質量比(SiO₂ )/(SiO₂ ＋B₂ O₃ )為0.50以上。 (6)如(1)至(5)中任一項記載之光學玻璃，其中質量比(SiO₂ )/(SiO₂ ＋B₂ O₃ )為0.95以下。 (7)如(1)至(6)中任一項記載之光學玻璃，其中以質量%計，ZrO₂ 成分之含量為25.0%以下。 (8)如(1)至(7)中任一項記載之光學玻璃，其係以質量%計而為 0～20.0%之K₂ O成分 0～20.0%之TiO₂ 成分 0～10.0%之MgO成分 0～10.0%之CaO成分 0～10.0%之SrO成分 0～20.0%之BaO成分 0～10.0%之Ta₂ O₅ 成分 0～10.0%之La₂ O₃ 成分 0～10.0%之Gd₂ O₃ 成分 0～20.0%之Y₂ O₃ 成分 0～10.0%之Yb₂ O₃ 成分 0～10.0%之P₂ O₅ 成分 0～10.0%之GeO₂ 成分 0～15.0%之Al₂ O₃ 成分 0～10.0%之Ga₂ O₃ 成分 0～10.0%之WO₃ 成分 0～10.0%之Bi₂ O₃ 成分 0～30.0%之ZnO成分 0～15.0%之TeO₂ 成分 0～5.0%之SnO₂ 成分 0～1.0%之Sb₂ O₃ 成分。 (9)如(1)至(8)中任一項記載之光學玻璃，其中Rn₂ O成分(式中，Rn為選自由Li、Na、K所組成之群中之一種以上)之質量和為1.0%以上且30.0%以下。 (10)如(1)至(9)中任一項記載之光學玻璃，其中質量比Li₂ O/Rn₂ O為0.01以上。 (11)如(1)至(10)中任一項記載之光學玻璃，其中RO成分(式中，R為選自由Mg、Ca、Sr、Ba所組成之群中之一種以上)之質量和為25.0%以下。 (12)如(1)至(11)中任一項記載之光學玻璃，其中Ln₂ O₃ 成分(式中，Ln為選自由Y、La、Gd、Yb所組成之群中之一種以上)之質量和為20.0%以下。 (13)一種研磨加工用及/或精密加壓成形用之預成形體，其包含如(1)至(12)中任一項記載之光學玻璃。 (14)一種光學元件，其包含如(1)至(12)中任一項記載之光學玻璃。 [發明之效果] 根據本發明，可獲得一種折射率(n_d )及阿貝數(ν_d )處於所需之範圍內、並且部分分散比(θg，F)較小之光學玻璃。[Problem to be Solved by the Invention] However, the partial dispersion ratio of the glass disclosed in Patent Document 1 is not small enough to be used as a lens for correcting the above-mentioned secondary spectrum. In addition, although the glass disclosed in Patent Document 2 has a relatively small partial dispersion ratio, its Abbe number is large, and therefore a glass with a smaller Abbe number is required. The present invention is made in view of the above-mentioned problems, and its purpose is to obtain an optical fiber with a refractive index ( _nd ) and Abbe number (ν _d ) within the desired range and with a small partial dispersion ratio (θg, F). Glass. [Technical means to solve the problem] The inventors of the present invention have made repeated efforts in experimental research to solve the above-mentioned problems. As a result, they have found that in glasses containing SiO ₂ components and Nb ₂ O ₅ components, high Glass with higher refractive index or lower Abbe number (higher dispersion), and lower partial dispersion ratio, thus completing the present invention. Specifically, the present invention provides the following. (1) An optical glass containing 10.0 to 70.0% of SiO ₂ components, 1.0 to 50.0% of Nb ₂ O ₅ components, and 1.0 to 30.0% of Na ₂ O components in mass %, and having 1.62 or more and Refractive index (n _d ) of 1.75 or less, Abbe number (ν _d ) of 30 or more and 42 or less, and partial dispersion ratio (θg, F) of 0.594 or less. (2) The optical glass described in (1), wherein the content of the B ₂ O ₃ component is 25.0% or less in mass %. (3) The optical glass described in (1) or (2), wherein the mass ratio (Li ₂ O+Na ₂ O)/(ZrO ₂ ) is 0.50 or more. (4) The optical glass according to any one of (1) to (3), wherein the Li ₂ O component content is 20.0% or less by mass%. (5) The optical glass according to any one of (1) to (4), wherein the mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) is 0.50 or more. (6) The optical glass according to any one of (1) to (5), wherein the mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) is 0.95 or less. (7) The optical glass according to any one of (1) to (6), wherein the content of the ZrO ₂ component is 25.0% or less in mass %. (8) The optical glass as described in any one of (1) to (7), which is 0 to 20.0% K ₂ O component 0 to 20.0% TiO ₂ component 0 to 10.0% by mass % MgO composition 0-10.0% CaO composition 0-10.0% SrO composition 0-20.0% BaO composition 0-10.0% Ta ₂ O ₅ composition 0-10.0% La ₂ O ₃ composition 0-10.0% Gd ₂ O ₃ 0-20.0% Y ₂ O ₃ 0-10.0% Yb ₂ O ₃ 0-10.0% P ₂ O ₅ 0-10.0% GeO ₂ 0-15.0% Al ₂ O ₃ Composition 0-10.0% Ga ₂ O ₃ Composition 0-10.0% WO ₃ Composition 0-10.0% Bi ₂ O ₃ Composition 0-30.0% ZnO Composition 0-15.0% TeO ₂ Composition 0-5.0% SnO _2. 0-1.0% Sb ₂ O ₃ component. (9) The optical glass as described in any one of (1) to (8), wherein the mass of the Rn ₂ O component (wherein, Rn is one or more selected from the group consisting of Li, Na, and K) and 1.0% or more and 30.0% or less. (10) The optical glass according to any one of (1) to (9), wherein the mass ratio Li ₂ O/Rn ₂ O is 0.01 or more. (11) The optical glass described in any one of (1) to (10), wherein the mass of the RO component (where R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) and below 25.0%. (12) The optical glass described in any one of (1) to (11), wherein the component is Ln ₂ O ₃ (wherein, Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) The mass sum is below 20.0%. (13) A preform for polishing and/or precision press molding, comprising the optical glass described in any one of (1) to (12). (14) An optical element comprising the optical glass described in any one of (1) to (12). [Effects of the Invention] According to the present invention, an optical glass having a refractive index ( _nd ) and Abbe number (ν _d ) within desired ranges and having a small partial dispersion ratio (θg, F) can be obtained.

本發明之光學玻璃以質量%計而含有10.0～70.0%之SiO₂ 成分、1.0～50.0%之Nb₂ O₅ 成分及1.0～30.0%之Na₂ O成分，且具有1.62以上且1.75以下之折射率(n_d )、30以上且42以下之阿貝數(ν_d )、及0.594以下之部分分散比(θg，F)。於含有SiO₂ 成分及Nb₂ O₅ 成分之玻璃中，可獲得具有所需範圍內之較高之折射率或較低之阿貝數(較高之分散)、與較低之部分分散比之玻璃。其中，第1光學玻璃以質量%計而含有10.0～70.0%之SiO₂ 成分、1.0～50.0%之Nb₂ O₅ 成分及1.0～30.0%之Na₂ O成分，且B₂ O₃ 成分之含量為20.0%以下，具有1.62以上且1.75以下之折射率(n_d )、30以上且42以下之阿貝數(ν_d )、及0.594以下之部分分散比(θg，F)。於含有SiO₂ 成分及Nb₂ O₅ 成分之玻璃中，即便於降低B₂ O₃ 成分之含量之情形時，亦可獲得具有所需範圍內之較高之折射率或較低之阿貝數(較高之分散)、與較低之部分分散比之玻璃。又，第2光學玻璃以質量%計而含有10.0～70.0%之SiO₂ 成分、1.0～50.0%之Nb₂ O₅ 成分及1.0～25.0%之Na₂ O成分，且質量比(Li₂ O＋Na₂ O)/(ZrO₂ )為0.50以上，具有1.64以上且1.70以下之折射率(n_d )、31以上且42以下之阿貝數(ν_d )、及0.590以下之部分分散比(θg，F)。於含有SiO₂ 成分及Nb₂ O₅ 成分之玻璃中，尤其即便於含有Na₂ O成分且質量比(Li₂ O＋Na₂ O)/(ZrO₂ )較大之情形時，亦可獲得具有所需範圍內之較高之折射率或較低之阿貝數(較高之分散)、與較低之部分分散比之玻璃。又，第3光學玻璃以質量%計而含有10.0～70.0%之SiO₂ 成分、1.0～50.0%之Nb₂ O₅ 成分、1.0～25.0%之Na₂ O成分及0.1～20.0%之Li₂ O成分，且具有1.62以上且1.75以下之折射率(n_d )、30以上且40以下之阿貝數(ν_d )、及0.594以下之部分分散比(θg，F)。於含有SiO₂ 成分及Nb₂ O₅ 成分之玻璃中，尤其即便於含有Na₂ O成分及Li₂ O成分之情形時，亦可獲得具有所需範圍內之較高之折射率或較低之阿貝數(較高之分散)、與較低之部分分散比之玻璃。因此，可獲得具有所需之較高之折射率(n_d )及較低之阿貝數(ν_d )、並且部分分散比(θg，F)較小而對光學系統之色像差之降低有用之光學玻璃。此外，藉由比重較小，可有助於光學機器之輕量化，藉由對可見光之透過率較高，可較佳地用於使可見光透過之用途，又，藉由玻璃轉移點較低，亦可獲得可降低再加熱加壓成形時之加熱溫度之光學玻璃。以下，對本發明之光學玻璃之實施形態詳細地進行說明，但本發明並不受以下之實施形態之任何限定，於本發明之目的之範圍內，可適宜加以變更而實施。再者，對於說明重複之部位，有適宜省略說明之情形，但並不限定發明之主旨。 [玻璃成分] 以下將對構成本發明之光學玻璃之各成分之組成範圍加以說明。於本說明書中，於未特別說明之情形時，各成分之含量係設定為以所有氧化物換算組成相對於玻璃之總質量之質量%表示者。此處，所謂「氧化物換算組成」，係指於假定被用作本發明之玻璃構成成分之原料的氧化物、複合鹽、金屬氟化物等在熔融時全部分解而變化為氧化物之情形時，將該生成氧化物之總質量設為100質量%而表述玻璃中所含之各成分之組成。＜關於必需成分、任意成分＞ SiO₂ 成分係促進穩定之玻璃形成，減少作為光學玻璃而欠佳之失透(結晶物之產生)之必需成分。尤其藉由將SiO₂ 成分之含量設為10.0%以上，可減少失透而不大幅度地提高部分分散比。又，藉此可減少再加熱時之失透或著色。因此，SiO₂ 成分之含量較佳為設為10.0%以上，更佳為設為超過20.0%，進而較佳為設為超過25.0%，進而較佳為設為超過30.0%，進而較佳為設為超過32.0%，進而較佳為設為超過34.0%，進而較佳為設為超過35.0%。另一方面，藉由將SiO₂ 成分之含量設為70.0%以下，折射率變得難以降低，由此容易獲得所需之高折射率，且可抑制部分分散比之上升。又，藉此可抑制玻璃原料之熔解性之降低。因此，SiO₂ 成分之含量較佳為設為70.0%以下，更佳為設為未達60.0%，進而較佳為設為未達50.0%，進而較佳為設為未達45.0%，進而較佳為設為未達43.0%，進而較佳為設為未達40.0%。 SiO₂ 成分可使用SiO₂ 、K₂ SiF₆ 、Na₂ SiF₆ 等作為原料。 Nb₂ O₅ 成分係藉由含有1.0%以上而可提高玻璃之折射率，降低阿貝數及部分分散比之必需成分。因此，Nb₂ O₅ 成分之含量較佳為設為1.0%以上，更佳為設為超過4.0%，進而較佳為設為超過7.0%，進而較佳為設為超過10.0%，進而較佳為設為超過15.0%，進而較佳為設為超過20.0%，進而較佳為設為超過23.0%，進而較佳為設為超過24.0%，進而較佳為設為超過25.0%，進而較佳為設為超過26.0%。另一方面，藉由將Nb₂ O₅ 成分之含量設為50.0%以下，可降低玻璃之材料成本。又，可抑制玻璃製造時之熔解溫度之上升，且減少因Nb₂ O₅ 成分之過量含有導致之失透。因此，Nb₂ O₅ 成分之含量較佳為設為50.0%以下，更佳為設為未達40.0%，進而較佳為設為未達35.0%，進而較佳為設為未達31.0%，進而較佳為設為未達30.0%。 Nb₂ O₅ 成分可使用Nb₂ O₅ 等作為原料。 Na₂ O成分係藉由含有1.0%以上而可降低玻璃之部分分散比，可提高再加熱加壓性，可降低玻璃轉移點，且可提高玻璃原料之熔解性之必需成分。因此，Na₂ O成分之含量較佳為設為1.0%以上，更佳為設為超過3.0%，進而較佳為設為超過5.0%，進而較佳為設為超過6.0%，進而較佳為設為超過8.5%，進而較佳為設為超過10.0%，進而較佳為設為超過11.0%，進而較佳為設為超過12.0%。另一方面，藉由將Na₂ O成分之含量設為30.0%以下，可抑制玻璃之折射率之降低，可使化學耐久性難以劣化，且可減少因過量含有導致之失透。因此，Na₂ O成分之含量較佳為設為30.0%以下，更佳為設為25.0%以下，進而較佳為設為未達20.0%，進而較佳為設為未達18.0%，進而較佳為設為未達15.0%，進而較佳為設為未達13.0%。 Na₂ O成分可使用Na₂ CO₃ 、NaNO₃ 、NaF、Na₂ SiF₆ 等作為原料。 B₂ O₃ 成分係於含有超過0%之情形時，可促進穩定之玻璃形成而減少失透，且提高玻璃原料之熔解性之任意成分。因此，B₂ O₃ 成分之含量亦可較佳為設為超過0%，更佳為設為超過1.0%，進而較佳為設為超過3.0%，進而較佳為設為超過4.0%，進而較佳為設為超過5.5%，進而較佳為設為超過7.5%，進而較佳為設為超過10.0%。另一方面，藉由將B₂ O₃ 成分之含量設為25.0%以下，可抑制折射率之降低或阿貝數之上升，且可抑制部分分散比之上升。因此，B₂ O₃ 成分之含量較佳為設為25.0%以下，更佳為設為20.0%以下，進而較佳為設為未達20.0%，進而較佳為設為未達16.0%，進而較佳為設為未達15.0%，進而較佳為設為未達12.5%。 B₂ O₃ 成分可使用H₃ BO₃ 、Na₂ B₄ O₇ 、Na₂ B₄ O₇ ・10H₂ O、BPO₄ 等作為原料。 Li₂ O成分及Na₂ O成分之合計量相對於ZrO₂ 成分之含量之比(質量比)較佳為0.50以上。藉此，可提高玻璃原料之熔解性，可減少玻璃之失透，又，可提高玻璃之再加熱加壓性。因此，該質量比(Li₂ O＋Na₂ O)/(ZrO₂ )亦可較佳為將0.50設為下限，更佳為將1.00設為下限，進而較佳為將1.30設為下限，進而較佳為將1.70設為下限，進而較佳為將1.78設為下限。另一方面，關於該質量比(Li₂ O＋Na₂ O)/(ZrO₂ )之上限，就減少玻璃之失透，提高玻璃原料之熔解性之觀點而言，亦可較佳為設為未達15.00，更佳為設為未達12.00，進而較佳為設為未達11.00。 ZrO₂ 成分係於含有超過0%之情形時，可提高玻璃之折射率，降低阿貝數，可降低部分分散比，且可減少失透之任意成分。又，藉此可減少再加熱時之失透或著色。因此，ZrO₂ 成分之含量亦可較佳為設為超過0%，更佳為設為超過1.0%，進而較佳為設為超過1.5%，進而較佳為設為超過3.0%，進而較佳為設為超過4.0%，進而較佳為設為超過5.0%，進而較佳為設為超過7.0%。另一方面，藉由將ZrO₂ 成分之含量設為25.0%以下，可減少失透，且可容易地獲得更均質之玻璃。因此，ZrO₂ 成分之含量較佳為設為25.0%以下，更佳為設為未達20.0%，進而較佳為設為未達18.0%，進而較佳為設為未達16.0%，進而較佳為設為未達15.0%，進而較佳為設為未達13.0%，進而較佳為設為未達10.0%，進而較佳為設為未達8.0%。 ZrO₂ 成分可使用ZrO₂ 、ZrF₄ 等作為原料。 Li₂ O成分係於含有超過0%之情形時，可降低玻璃之部分分散比，可提高再加熱加壓性，可降低玻璃轉移點，且可提高玻璃原料之熔解性之任意成分。尤其於第3光學玻璃中，Li₂ O成分係藉由含有0.1%以上而可降低玻璃之部分分散比，可提高再加熱加壓性，可降低玻璃轉移點，且可提高玻璃原料之熔解性之必需成分。本發明之光學玻璃中之Li₂ O成分之含量亦可較佳為設為0.1%以上，更佳為設為超過0.5%，進而較佳為設為超過1.0%，進而較佳為設為超過2.0%，進而較佳為設為超過2.5%。另一方面，藉由將Li₂ O成分之含量設為20.0%以下，可抑制折射率之降低，可使化學耐久性難以劣化，且可減少因過量含有導致之失透。因此，Li₂ O成分之含量較佳為設為20.0%以下，更佳為設為未達10.0%，進而較佳為設為未達8.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.4%。 Li₂ O成分可使用Li₂ CO₃ 、LiNO₃ 、LiF等作為原料。 K₂ O成分係於含有超過0%之情形時，可降低折射率，可提高玻璃原料之熔解性，且可降低玻璃轉移點之任意成分。另一方面，藉由將K₂ O成分之含量設為20.0%以下，可抑制部分分散比之上升，減少失透，且可使化學耐久性難以劣化。又，可抑制再加熱加壓成形性之降低。因此，K₂ O成分之含量較佳為設為20.0%以下，更佳為設為15.0%以下，進而較佳為設為未達15.0%，進而較佳為設為未達12.0%，進而較佳為設為未達11.0%，進而較佳為設為未達10.0%，進而較佳為設為未達8.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。 K₂ O成分可使用K₂ CO₃ 、KNO₃ 、KF、KHF₂ 、K₂ SiF₆ 等作為原料。 TiO₂ 成分係於含有超過0%之情形時，可提高折射率，降低阿貝數，且減少失透之任意成分。另一方面，藉由將TiO₂ 成分之含量設為20.0%以下，可減少玻璃之著色，提高內部透過率。又，藉此而部分分散比變得難以上升，故而可容易地獲得所需之較低之部分分散比。因此，TiO₂ 成分之含量較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%，進而較佳為設為未達0.1%。 TiO₂ 成分可使用TiO₂ 等作為原料。 MgO成分係於含有超過0%之情形時，可降低玻璃之熔解溫度之任意成分。另一方面，藉由將MgO成分之含量設為10.0%以下，可抑制折射率之降低或阿貝數之上升，且減少失透。因此，MgO成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%，進而較佳為設為未達0.5%。 MgO成分可使用MgO、MgCO₃ 、MgF₂ 等作為原料。 CaO成分係於含有超過0%之情形時，可降低玻璃之材料成本並且減少失透，且可提高玻璃原料之熔解性之任意成分。另一方面，藉由將CaO成分之含量設為10.0%以下，可抑制折射率之降低或阿貝數之上升、部分分散比之上升，且可減少失透。因此，CaO成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.9%，進而較佳為設為未達0.5%。 CaO成分可使用CaCO₃ 、CaF₂ 等作為原料。 SrO成分係於含有超過0%之情形時，可減少玻璃之失透，且可提高折射率之任意成分。尤其藉由將SrO成分之含量設為10.0%以下，可抑制阿貝數之上升，並且可抑制化學耐久性之劣化。因此，SrO成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 SrO成分可使用Sr(NO₃ )₂ 、SrF₂ 等作為原料。 BaO成分係於含有超過0%之情形時，可減少玻璃之失透，且可提高折射率，可提高玻璃原料之熔解性，且與其他鹼土成分相比可降低玻璃之材料成本之任意成分。又，亦係可抑制再加熱加壓成形性之降低之成分。另一方面，藉由將BaO成分之含量設為20.0%以下，可抑制阿貝數之上升，並且可抑制化學耐久性之劣化、或失透。因此，BaO成分之含量較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%。 BaO成分可使用BaCO₃ 、Ba(NO₃ )₂ 等作為原料。 Ta₂ O₅ 成分係於含有超過0%之情形時，可提高折射率，降低部分分散比，且減少玻璃之失透之任意成分。另一方面，藉由將Ta₂ O₅ 成分之含量設為10.0%以下，而減少作為稀有礦物資源之Ta₂ O₅ 成分之使用量，且玻璃變得容易於更低溫下熔解，故而可降低玻璃之材料成本或生產成本。又，藉此可減少因Ta₂ O₅ 成分之過量含有導致之玻璃之失透、或阿貝數之上升。因此，Ta₂ O₅ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%，進而較佳為設為未達0.5%。尤其就降低玻璃之材料成本之觀點而言，亦可將Ta₂ O₅ 成分之含量設為未達0.1%。 Ta₂ O₅ 成分可使用Ta₂ O₅ 等作為原料。 La₂ O₃ 成分、Gd₂ O₃ 成分、Y₂ O₃ 成分及Yb₂ O₃ 成分係藉由含有超過0%之至少任一者而可提高折射率，且減小部分分散比之任意成分。另一方面，藉由將La₂ O₃ 成分之含量設為10.0%以下，可抑制阿貝數之上升，可減小比重，且可減少失透。因此，La₂ O₃ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。又，藉由將Y₂ O₃ 成分之含量設為20.0%以下，可抑制阿貝數之上升，可減小比重，可減少失透。因此，Y₂ O₃ 成分之含量較佳為設為20.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。又，藉由將Gd₂ O₃ 成分及Yb₂ O₃ 成分各自之含量設為10.0%以下，可抑制阿貝數之上升，可減小比重，可減少失透，且可降低材料成本。因此，Gd₂ O₃ 成分及Yb₂ O₃ 成分各自之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 La₂ O₃ 成分、Gd₂ O₃ 成分、Y₂ O₃ 成分及Yb₂ O₃ 成分可使用La₂ O₃ 、La(NO₃ )₃ ・XH₂ O(X為任意之整數)、Y₂ O₃ 、YF₃ 、Gd₂ O₃ 、GdF₃ 、Yb₂ O₃ 等作為原料。 P₂ O₅ 成分係於含有超過0%之情形時，可減少玻璃之失透之任意成分。另一方面，藉由將P₂ O₅ 成分之含量設為10.0%以下，可減少因P₂ O₅ 成分之過量含有導致之失透。因此，P₂ O₅ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 P₂ O₅ 成分可使用Al(PO₃ )₃ 、Ca(PO₃ )₂ 、Ba(PO₃ )₂ 、BPO₄ 、H₃ PO₄ 等作為原料。 GeO₂ 成分係於含有超過0%之情形時，可提高折射率，且減少失透之任意成分。另一方面，藉由將GeO₂ 成分之含量設為10.0%以下，可減少昂貴之GeO₂ 成分之使用量，故而可降低玻璃之材料成本。因此，GeO₂ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達1.0%。 GeO₂ 成分可使用GeO₂ 等作為原料。 Al₂ O₃ 成分及Ga₂ O₃ 成分係於含有超過0%之至少任一者之情形時，可提高化學耐久性，且減少玻璃之失透之任意成分。另一方面，藉由將Al₂ O₃ 成分之含量設為15.0%以下，可減少因過量之含有導致之失透。因此，Al₂ O₃ 成分之含量較佳為設為15.0%以下，更佳為設為未達8.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。又，藉由將Ga₂ O₃ 成分之含量設為10.0%以下，可減少因過量之含有導致之失透。因此，Ga₂ O₃ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%。 Al₂ O₃ 成分及Ga₂ O₃ 成分可使用Al₂ O₃ 、Al(OH)₃ 、AlF₃ 、Ga₂ O₃ 、Ga(OH)₃ 等作為原料。 WO₃ 成分係於含有超過0%之情形時，可提高折射率而降低阿貝數，減少玻璃之失透，且可提高玻璃原料之熔解性之任意成分。另一方面，藉由將WO₃ 成分之含量設為10.0%以下，可使玻璃之部分分散比難以上升，且可減少玻璃之著色而提高內部透過率。因此，WO₃ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 WO₃ 成分可使用WO₃ 等作為原料。 Bi₂ O₃ 成分係於含有超過0%之情形時，可提高折射率而降低阿貝數，且可降低玻璃轉移點之任意成分。另一方面，藉由將Bi₂ O₃ 成分之含量設為10.0%以下，可使部分分散比難以上升，且可減少玻璃之著色而提高內部透過率。因此，Bi₂ O₃ 成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 Bi₂ O₃ 成分可使用Bi₂ O₃ 等作為原料。 ZnO成分係含有超過0%之情形時，可減少玻璃之失透，降低部分分散比，且可降低玻璃轉移點之任意成分。另一方面，藉由將ZnO成分之含量設為30.0%以下，可減少玻璃之再加熱時之失透或著色，並且提高化學耐久性。因此，ZnO成分之含量較佳為設為30.0%以下，更佳為設為未達20.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達2.0%，進而較佳為設為未達1.0%。 ZnO成分可使用ZnO、ZnF₂ 等作為原料。 TeO₂ 成分係於含有超過0%之情形時，可提高折射率，降低部分分散比，且可降低玻璃轉移點之任意成分。另一方面，藉由將TeO₂ 成分之含量設為15.0%以下，可減少玻璃之著色而提高內部透過率。又，藉由減少昂貴之TeO₂ 成分之使用，可獲得材料成本更低之玻璃。因此，TeO₂ 成分之含量較佳為設為15.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 TeO₂ 成分可使用TeO₂ 等作為原料。 SnO₂ 成分係於含有超過0%之情形時，可使熔解之玻璃澄清(脫泡)，且可提高玻璃之可見光透過率之任意成分。另一方面，藉由將SnO₂ 成分之含量設為5.0%以下，可使因熔融玻璃之還原導致之玻璃之著色、或玻璃之失透難以產生。又，可減少SnO₂ 成分與熔解設備(尤其是Pt等貴金屬)之合金化，故而可實現熔解設備之長壽命化。因此，SnO₂ 成分之含量較佳為設為5.0%以下，更佳為設為未達3.0%，進而較佳為設為未達1.0%。 SnO₂ 成分可使用SnO、SnO₂ 、SnF₂ 、SnF₄ 等作為原料。 Sb₂ O₃ 成分係於含有超過0%之情形時，可使玻璃澄清之任意成分。另一方面，藉由將Sb₂ O₃ 成分之含量設為1.0%以下，可使玻璃熔解時之過度之發泡難以產生，故而可使Sb₂ O₃ 成分與熔解設備(尤其是Pt等貴金屬)難以合金化。因此，Sb₂ O₃ 成分之含量較佳為將1.0%以下設為上限，更佳為將未達0.5%設為上限，進而較佳為將未達0.1%設為上限。然而，於重視光學玻璃之環境上之影響之情形時，亦可不含有Sb₂ O₃ 成分。 Sb₂ O₃ 成分可使用Sb₂ O₃ 、Sb₂ O₅ 、Na₂ H₂ Sb₂ O₇ ・5H₂ O等作為原料。再者，使玻璃澄清之成分並不限定於上述Sb₂ O₃ 成分，可使用玻璃製造之領域中之公知之澄清劑、或該等之組合。 SiO₂ 成分之含量相對於SiO₂ 成分及B₂ O₃ 成分之合計量之比(質量比)亦可設為0.10以上。藉此，可抑制玻璃之阿貝數之上升。因此，該質量比(SiO₂ )/(SiO₂ ＋B₂ O₃ )亦可較佳為將0.10設為下限，更佳為將0.30設為下限，進而較佳為將0.50設為下限，進而較佳為將0.65設為下限，進而較佳為將0.75設為下限。另一方面，該質量比(SiO₂ )/(SiO₂ ＋B₂ O₃ )之上限亦可為1，但就抑制玻璃轉移點之上升，減少玻璃之失透，提高玻璃原料之熔解性之觀點而言，亦可較佳為設為未達1，更佳為設為未達0.98，進而較佳為設為0.95以下，進而較佳為設為未達0.95，進而較佳為設為0.93以下，進而較佳為設為0.90以下，進而較佳為設為0.88以下，進而較佳為設為0.83以下，進而較佳為設為0.80以下。 Rn₂ O成分(式中，Rn為選自由Li、Na、K所組成之群中之一種以上)之含量之和(質量和)較佳為1.0%以上且30.0%以下。尤其藉由將該質量和設為1.0%以上，可提高玻璃原料之熔解性，且降低玻璃轉移點。因此，Rn₂ O成分之合計含量亦可較佳為設為1.0%以上，更佳為設為超過5.0%，進而較佳為設為超過10.0%，進而較佳為設為超過12.0%。另一方面，藉由將該質量和設為30.0%以下，可使玻璃之折射率難以降低，可減少玻璃形成時之失透。因此，Rn₂ O成分之合計含量較佳為設為30.0%以下，更佳為設為未達25.0%，進而較佳為設為未達23.0%，進而較佳為設為未達21.0%，進而較佳為設為未達20.0%，進而較佳為設為未達18.0%。質量比Li₂ O/Rn₂ O較佳為0.01以上。藉此可降低玻璃之部分分散比，可提高再加熱加壓性，可降低玻璃轉移點。因此，該質量比Li₂ O/Rn₂ O較佳為設為0.01以上，更佳為設為超過0.05，進而較佳為設為超過0.10，進而較佳為設為超過0.14。另一方面，關於該質量比Li₂ O/Rn₂ O之上限，就減少玻璃之失透之觀點而言，亦可較佳為設為0.60，更佳為設為0.50，進而較佳為設為0.40。 RO成分(式中，R為選自由Mg、Ca、Sr、Ba所組成之群中之一種以上)之含量之和(質量和)較佳為25.0%以下。藉此可抑制阿貝數之上升，且可減少因該等成分之過量含有導致之玻璃之失透。因此，RO成分之質量和較佳為設為25.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達2.0%。 Ln₂ O₃ 成分(式中，Ln為選自由La、Gd、Y、Yb所組成之群中之一種以上)之含量之和(質量和)較佳為20.0%以下。藉此，可減少玻璃之失透，可抑制阿貝數之上升，且可降低材料成本。因此，Ln₂ O₃ 成分之質量和較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。＜關於不應含有之成分＞繼而，對於本發明之光學玻璃中不應含有之成分、及含有則欠佳之成分進行說明。可於不損及本案發明之玻璃之特性之範圍內視需要添加其他成分。其中，除Ti、Zr、Nb、W、La、Gd、Y、Yb、Lu以外，V、Cr、Mn、Fe、Co、Ni、Cu、Ag及Mo等各種過渡金屬成分即便於單獨或複合地含有少量各者之情形時，玻璃亦著色，具有於可見光範圍之特定之波長下產生吸收之性質，故而尤其於使用可見光範圍之波長之光學玻璃中，較佳為實質上不含有。又，PbO等鉛化合物及As₂ O₃ 等砷化合物由於為環境負荷較高之成分，故而較理想為實質上不含有，即除了不可避免之混入以外全部不含有。進而，Th、Cd、Tl、Os、Be、及Se之各種成分有作為近年有害之化學物質而控制使用之傾向，不僅是玻璃之製造步驟，而且至加工步驟、及製品化後之處理為止亦必需環境對策上之措施。因此，於重視環境上之影響之情形時，較佳為實質上不含有該等。 [製造方法] 本發明之光學玻璃例如係以如下方式製作。即，藉由以下方式製作：將上述原料以各成分成為特定之含量之範圍內之方式均勻地混合，將所製作之混合物投入至鉑坩堝、石英坩堝或氧化鋁坩堝中進行粗熔融後，放入至金坩堝、鉑坩堝、鉑合金坩堝或銥坩堝中並於1100～1400℃之溫度範圍內熔融3～5小時，進行攪拌均質化並進行消泡等之後，降低至1000～1400℃之溫度後進行精加工攪拌而將脈理去除，澆鑄至模具中進行緩冷。此時，較佳為使用熔解性較高者作為玻璃原料。藉此，可實現更低溫下之熔解、或更短時間內之熔解，故而可提高玻璃之生產性，降低生產成本。又，由於成分之揮發或與坩堝等之反應得以減少，故而可容易地獲得著色較少之玻璃。＜物性＞本發明之光學玻璃具有較高之折射率與特定之範圍之阿貝數。本發明之光學玻璃之折射率(n_d )較佳為將1.62設為下限，更佳為將1.63設為下限，進而較佳為將1.64設為下限，進而較佳為將1.65設為下限。該折射率之上限亦可較佳為1.75，更佳為1.74，進而較佳為1.72，進而較佳為1.70，進而較佳為1.68。本發明之光學玻璃之阿貝數(ν_d )較佳為設為42以下，更佳為設為40以下，進而較佳為設為39以下，進而較佳為設為38以下。另一方面，本發明之光學玻璃之阿貝數(ν_d )較佳為將30設為下限，更佳為將32設為下限，進而較佳為將33設為下限，進而較佳為將34設為下限。具有此種折射率及阿貝數之本發明之光學玻璃係於光學設計上有用，尤其可實現較高之成像特性等，亦同時實現光學系統之小型化，故而可擴展光學設計之自由度。此處，本發明之光學玻璃較佳為折射率(nd)及阿貝數(νd)滿足(‑0.012νd＋2.04)≦nd≦(-0.012νd＋2.16)之關係。於本發明中特定之組成之玻璃中，藉由折射率(nd)及阿貝數(νd)滿足該關係，可獲得更難以引起失透之玻璃。因此，於本發明之光學玻璃中，較佳為折射率(nd)及阿貝數(νd)滿足nd≧(-0.012νd＋2.04)之關係，更佳為滿足nd≧(-0.012νd＋2.05)之關係，進而較佳為滿足nd≧(-0.012νd＋2.06)之關係，進而較佳為滿足nd≧(‑0.012νd＋2.08)之關係。另一方面，於本發明之光學玻璃中，較佳為折射率(nd)及阿貝數(νd)滿足nd≦(-0.012νd＋2.16)之關係，更佳為滿足nd≦(-0.012νd＋2.14)之關係，進而較佳為滿足nd≦(-0.012νd＋2.13)之關係，進而較佳為滿足nd≦(-0.012νd＋2.12)之關係。本發明之光學玻璃具有較低之部分分散比(θg，F)。更具體而言，本發明之光學玻璃之部分分散比(θg，F)較佳為將0.594設為上限，更佳為將0.592設為上限，進而較佳為將0.590設為上限，進而較佳為將0.588設為上限。該部分分散比(θg，F)之下限亦可較佳為0.570，更佳為0.573，進而較佳為0.575，進而較佳為0.576，進而較佳為0.577。又，本發明之光學玻璃之部分分散比(θg，F)較佳為於與阿貝數(ν_d )之間滿足(-0.00162×ν_d ＋0.630)≦(θg，F)≦(-0.00162×ν_d ＋0.652)之關係。藉此，可獲得具有較低之部分分散比(θg，F)之光學玻璃，故而可使由該光學玻璃所形成之光學元件對光學系統之色像差之降低發揮作用。因此，於本發明之光學玻璃中，較佳為部分分散比(θg，F)及阿貝數(νd)滿足θg，F≧(-0.00162×ν_d ＋0.630)之關係，更佳為滿足θg，F≧(‑0.00162×ν_d ＋0.632)之關係，進而較佳為滿足θg，F≧(-0.00162×ν_d ＋0.634)之關係。另一方面，於本發明之光學玻璃中，較佳為部分分散比(θg，F)及阿貝數(νd)滿足θg，F≦(-0.00162×ν_d ＋0.652)之關係，更佳為滿足θg，F≦(-0.00162×ν_d ＋0.650)之關係，進而較佳為滿足θg，F≦(-0.00162×ν_d ＋0.648)之關係，進而較佳為滿足θg，F≦(-0.00162×ν_d ＋0.646)之關係，進而較佳為滿足θg，F≦(-0.00162×ν_d ＋0.643)之關係。再者，表示於上述之部分分散比(θg，F)及阿貝數(νd)之關係式中，藉由使用與標準線相同斜率之直線規定該等之關係，可獲得與通常之玻璃相比部分分散比(θg，F)較小之玻璃。本發明之光學玻璃較佳為比重較小。更具體而言，本發明之光學玻璃之比重較佳為3.80[g/cm³ ]以下。藉此，降低光學元件或使用其之光學機器之質量，故而可有助於光學機器之輕量化。因此，本發明之光學玻璃之比重較佳為將3.80設為上限，更佳為將3.50設為上限，進而較佳為將3.30設為上限，進而較佳為將3.10設為上限，進而較佳為將3.00設為上限。再者，本發明之光學玻璃之比重為大概2.50以上，更詳細而言，為2.70以上，進而詳細而言，為2.80以上之情況較多。本發明之光學玻璃之比重係根據日本光學玻璃工業會標準JOGIS05-1975「光學玻璃之比重之測定方法」而測定。本發明之光學玻璃較佳為著色較少。尤其本發明之光學玻璃於厚度10 mm之樣品中顯示出分光透過率5%之波長(λ₅ )較佳為400 nm以下，更佳為380 nm以下，進而較佳為350 nm以下。又，本發明之光學玻璃於厚度10 mm之樣品中顯示出分光透過率80%之波長(λ₈₀ )較佳為450 nm以下，更佳為420 nm以下，進而較佳為400 nm以下。藉此，玻璃之吸收端位於紫外線範圍之附近，可提高可見光範圍之玻璃之透明性，故而可較佳地將該光學玻璃用作透鏡等光學元件之材料。本發明之光學玻璃較佳為具有650℃以下之玻璃轉移點。藉此，玻璃於更低之溫度下軟化，故而可於更低之溫度下將玻璃模壓成形。又，亦可減少用於模壓成形之模具之氧化而實現模具之長壽命化。因此，本發明之光學玻璃之玻璃轉移點較佳為將650℃設為上限，更佳為將620℃設為上限，進而較佳為將600℃設為上限，進而較佳為將580℃設為上限，進而較佳為將550℃設為上限。再者，本發明之光學玻璃之玻璃轉移點之下限並無特別限定，但本發明之光學玻璃之玻璃轉移點亦可較佳為將460℃設為下限，更佳為將480℃設為下限，進而較佳為將500℃設為下限。本發明之光學玻璃較佳為具有720℃以下之屈服點(At)。屈服點係與玻璃轉移點同樣地表示玻璃之軟化性之指標之一，且係表示接近加壓成形溫度之溫度之指標。因此，藉由使用屈服點為720℃以下之玻璃，可實現更低溫度下之加壓成形，故而可更容易地進行加壓成形。因此，本發明之光學玻璃之屈服點較佳為將720℃設為上限，更佳為將700℃設為上限，進而較佳為將690℃設為上限，進而較佳為將680℃設為上限，進而較佳為將660℃設為上限，進而較佳為將650℃設為上限，進而較佳為將630℃設為上限。再者，本發明之光學玻璃之屈服點並無特別限定，但亦可較佳為將500℃設為下限，更佳為將530℃設為下限，進而較佳為將560℃設為下限。本發明之光學玻璃較佳為平均線膨脹係數(α)較小。尤其本發明之光學玻璃之平均線膨脹係數較佳為將150×10^-7 K^-1 設為上限，更佳為將120×10^-7 K^-1 設為上限，進而較佳為將115×10^-7 K^-1 設為上限，進而較佳為將110×10^-7 K^-1 設為上限，進而較佳為將100×10^-7 K^-1 設為上限。藉此，於利用成形模具將光學玻璃進行加壓成形時，減少因玻璃之溫度變化導致之膨脹或收縮之總量。因此，可於加壓成形時使光學玻璃難以破裂，可提高光學元件之生產性。本發明之光學玻璃較佳為再加熱加壓成形性良好。更具體而言，本發明之光學玻璃較佳為即便於再加熱試驗(脫模試驗)之前後亦不產生失透及乳白。藉此，亦難以因假定再加熱加壓加工之再加熱試驗而難以引起失透及著色，由此，玻璃之光線透過率難以喪失，故而可容易地對玻璃進行以再加熱加壓加工為代表之再加熱處理。即，由於可利用加壓成形而製作複雜形狀之光學元件，故而可實現製造成本廉價、且生產性良好之光學元件製造。此處，再加熱試驗(脫模試驗)可藉由如下方法進行：將15 mm×15 mm×30 mm之試片載置於凹型耐火物上並放入至電爐中進行再加熱，自常溫起歷時150分鐘升溫至較各試樣之轉移溫度(Tg)高80℃～150℃之溫度(掉落至耐火物中之溫度)，於該溫度下保溫30分鐘後，冷卻至常溫並取出至爐外，以可於內部觀察之方式將相對向之兩面研磨至厚度10 mm後，目視觀察經研磨之玻璃試樣。再者，再加熱試驗(脫模試驗)之前後之失透及乳白之有無例如可利用目視而確認，「不產生失透及乳白」例如係指將再加熱試驗(脫模試驗)後之試片之波長587.56 nm之光線(d射線)之透過率除以再加熱試驗前之試片之d射線之透過率所得之值為大概0.80以上。本發明之光學玻璃較佳為具有較高之化學耐久性。更具體而言，本發明之光學玻璃較佳為具有較高之耐水性或耐酸性。藉此，於對光學玻璃進行研磨加工時，可減少因清洗液或研磨液導致之玻璃之模糊，故而可更容易地進行研磨加工。再者，光學玻璃之耐水性及耐酸性係指於依據日本光學玻璃工業會標準「光學玻璃之化學耐久性之測定方法」JOGIS06-2008之化學耐久性(耐水性、耐酸性)中，較佳為1～3級、更佳為1～2級、進而較佳為1級。本發明之光學玻璃較佳為於玻璃製作時難以引起失透。藉此，可抑制因玻璃製作時之玻璃之結晶化等導致的透過率之降低，故而可較佳地將該光學玻璃用於透鏡等使可見光透過之光學元件。再者，作為表示玻璃製作時之難以引起失透之程度之尺度，例如可列舉液相溫度較低。 [預成形體及光學元件] 可由所製作之光學玻璃，使用例如再加熱加壓成形或精密加壓成形等模壓成形之方法而製作玻璃成形體。即，可由光學玻璃製作模壓成形用之預成形體，對該預成形體進行再加熱加壓成形後進行研磨加工而製作玻璃成形體，或例如對進行研磨加工所製作之預成形體進行精密加壓成形而製作玻璃成形體。再者，製作玻璃成形體之方法並不限定於該等方法。以如此之方式所製作之玻璃成形體於各種光學元件中有用，其中，尤佳為用於透鏡或稜鏡等光學元件之用途。藉此，可減少設有光學元件之光學系統之透過光的因色像差導致之色之模糊。因此，於將該光學元件用於相機之情形時可更準確地表現攝影對象物，於將該光學元件用於投影儀之情形時可更高清地投影所需之影像。 [實施例] 將本發明之實施例(No.A1～No.A27、No.B1～No.B11、No.C1～No.C12)之組成、及折射率(n_d )、阿貝數(ν_d )、部分分散比(θg，F)、分光透過率顯示5%及80%之波長(λ₅ 、λ₈₀ )、玻璃轉移點(Tg)、屈服點(At)、平均線膨脹係數(α)及比重之結果示於表1～8。此處，實施例(No.A1～No.A27)亦可作為第1光學玻璃之實施例，實施例(No.B1～No.B11)亦可作為第2光學玻璃之實施例，實施例(No.C1～No.C12)亦可作為第3光學玻璃之實施例，但並不限定於此。再者，以下之實施例僅用於例示，並非僅限定於該等實施例。實施例之玻璃均係分別選定相應之氧化物、氫氧化物、碳酸鹽、硝酸鹽、氟化物、氫氧化物、偏磷酸化合物等通常之光學玻璃中所使用之高純度之原料作為各成分之原料，以成為表中所示之各實施例之組成之比率之方式稱量並均勻地混合後，投入至鉑坩堝中，根據玻璃原料之熔解難易度而利用電爐於1100～1400℃之溫度範圍內熔解3～5小時，攪拌均質化而進行消泡等之後，將溫度降低至1000～1400℃並進行攪拌均質化後澆鑄至模具中，進行緩冷而製作玻璃。實施例之玻璃之折射率(n_d )、阿貝數(ν_d )及部分分散比(θg，F)係根據日本光學玻璃工業會標準JOGIS01-2003而測定。並且，由所獲得之折射率(n_d )及阿貝數(ν_d )之值，求出關係式(n_d ＝‑a×ν_d ＋b)中之斜率a為0.012時之截距b。又，由所獲得之阿貝數(ν_d )及部分分散比(θg，F)之值，求出關係式(θg，F＝-a'×ν_d ＋b')中之斜率a'為0.00162時之截距b'。再者，用於本測定之玻璃係使用將緩冷降溫速度設為-25℃/hr而利用緩冷爐而進行處理者。實施例之玻璃之透過率係依據日本光學玻璃工業會標準JOGIS02而測定。再者，於本發明中，藉由測定玻璃之透過率，而求出玻璃之著色之有無與程度。具體而言，對厚度10±0.1 mm之對面平行研磨品依據JISZ8722測定200～800 nm之分光透過率，求出λ₅ (透過率5%時之波長)及λ₈₀ (透過率80%時之波長)。實施例之玻璃之玻璃轉移點(Tg)及屈服點(At)係由藉由依據日本光學玻璃工業會標準JOGIS08-2003「光學玻璃之熱膨脹之測定方法」測定溫度與試樣之伸長率之關係所獲得的熱膨脹曲線而求出。實施例之玻璃之平均線膨脹係數(α)係依據日本光學玻璃工業會標準JOGIS08-2003「光學玻璃之熱膨脹之測定方法」，求出100～300℃下之平均線膨脹係數。實施例之玻璃之比重係根據日本光學玻璃工業會標準JOGIS05-1975「光學玻璃之比重之測定方法」而測定。 [表1]

[表2]

[表3]

[表4]

[表5]

[表6]

[表7]

[表8]

如該等表般，實施例之光學玻璃之部分分散比(θg，F)為0.594以下，更具體而言為0.593以下，為所需之範圍內。尤其實施例(No.B1～No.B11)之光學玻璃之部分分散比(θg，F)為0.590以下。此處，本發明之實施例之光學玻璃之部分分散比(θg，F)及阿貝數(νd)滿足(-0.00162×ν_d ＋0.630)≦(θg，F)≦(-0.00162×ν_d ＋0.652)之關係。尤其實施例(No.C1～No.C12)之光學玻璃滿足(θg，F)≦(-0.00162×ν_d ＋0.650)之關係。又，實施例(No.B1～No.B11)之光學玻璃滿足(θg，F)≦(-0.00162×ν_d ＋0.647)之關係。並且，關於本案之實施例之玻璃之部分分散比(θg，F)與阿貝數(ν_d )之關係係成為如圖2所示般。因此表明，本發明之實施例之光學玻璃具有較小之部分分散比(θg，F)。本發明之實施例之光學玻璃均係折射率(n_d )為1.62以上，更詳細而言為1.64以上，為所需之範圍內。尤其實施例(No.C1～No.C12)之光學玻璃之折射率(n_d )為1.66以上。又，本發明之光學玻璃之折射率(n_d )為1.75以下。尤其實施例(No.B1～No.B11)之光學玻璃之折射率(n_d )為1.68以下。又，本發明之實施例之光學玻璃均係阿貝數(ν_d )為30以上，並且該阿貝數(ν_d )為42以下，更詳細而言為41以下，為所需之範圍內。尤其實施例(No.A1～No.A27、No.B1～No.B11)之光學玻璃之阿貝數(ν_d )為34以上。另一方面，實施例(No.C1～No.C12)之光學玻璃之阿貝數(ν_d )為39以下。此處，本發明之實施例之光學玻璃之折射率(nd)及阿貝數(νd)滿足(‑0.012νd＋2.04)≦nd≦(-0.012νd＋2.16)之關係，更詳細而言，滿足(‑0.012νd＋2.08)≦nd≦(-0.012νd＋2.16)之關係。尤其實施例(No.A1～No.A27)之光學玻璃之折射率(nd)及阿貝數(νd)滿足(-0.012νd＋2.08)≦nd≦(-0.012νd＋2.13)之關係。又，實施例(No.B1～No.B11)之光學玻璃之折射率(nd)及阿貝數(νd)滿足(-0.012νd＋2.08)≦nd≦(-0.012νd＋2.11)之關係。又，實施例(No.C1～No.C12)之光學玻璃之折射率(nd)及阿貝數(νd)滿足(-0.012νd＋2.09)≦nd≦(-0.012νd＋2.16)之關係。並且，關於本案之實施例之玻璃之折射率(nd)及阿貝數(νd)之關係係成為如圖3所示般。因此，表明實施例之光學玻璃係折射率(n_d )及阿貝數(ν_d )為所需之範圍內、且部分分散比(θg，F)較小之光學玻璃。此外，實施例之光學玻璃之λ₅ (透過率5%時之波長)均為400 nm以下，更詳細而言為350 nm以下。尤其實施例(No.B1～No.B11)之光學玻璃之λ₅ (透過率5%時之波長)均為340 nm以下。又，實施例之光學玻璃之λ₈₀ (透過率80%時之波長)均為450 nm以下，更詳細而言為440 nm以下。尤其實施例(No.B1～No.B11)之光學玻璃之λ₈₀ (透過率80%時之波長)均為390 nm以下。又，實施例(No.C1～No.C12)之光學玻璃之λ₈₀ (透過率80%時之波長)均為420 nm以下。因此亦表明，實施例之光學玻璃係對可見光之透過率較高且著色較少。又，實施例之光學玻璃之比重均為3.80以下，更詳細而言為3.60以下，為所需之範圍內。尤其實施例(No.A1～No.A27)之光學玻璃之比重為3.30以下。又，實施例(No.B1～No.B11)之光學玻璃之比重為3.00以下。又，實施例之光學玻璃之玻璃轉移點為650℃以下，更詳細而言為630℃以下。尤其實施例(No.B1～No.B11)之光學玻璃之玻璃轉移點為600℃以下。又，實施例(No.C1～No.C12)之光學玻璃之玻璃轉移點為550℃以下。又，實施例之光學玻璃之屈服點均為700℃以下，為所需之範圍內。尤其實施例(No.B1～No.B11)之光學玻璃之屈服點為670℃以下。又，實施例(No.C1～No.C12)之光學玻璃之屈服點為620℃以下。推測藉此，可於更低之溫度下將玻璃模壓成形。又，實施例之光學玻璃之平均線膨脹係數(α)為150×10^-7 K^-1 以下，更詳細而言為140×10^-7 K^-1 以下，為所需之範圍內。尤其實施例(No.B1～No.B11、No.C1～No.C12)之光學玻璃之平均線膨脹係數(α)為110×10^-7 K^-1 以下。進而，使用實施例之光學玻璃而形成透鏡預成形體，對該透鏡預成形體進行模壓成形，結果可於不引起失透或乳白之情況下加工成各種透鏡形狀。以上，以例示之目的對本發明詳細地進行了說明，但本實施例並非僅為例示之目的，應理解可由業者於不脫離本發明之思想及範圍之情況下實現多種改變。The optical glass of the present invention contains 10.0-70.0% of SiO ₂ components, 1.0-50.0% of Nb ₂ O ₅ components and 1.0-30.0% of Na ₂ O components in terms of mass %, and has a refraction of 1.62 to 1.75 Ratio (n _d ), Abbe number (ν _d ) of 30 or more and 42 or less, and partial dispersion ratio (θg, F) of 0.594 or less. In glasses containing SiO ₂ components and Nb ₂ O ₅ components, a higher refractive index or a lower Abbe number (higher dispersion) and a lower partial dispersion ratio within the desired range can be obtained. Glass. Among them, the first optical glass contains 10.0-70.0% of SiO ₂ components, 1.0-50.0% of Nb ₂ O ₅ components, and 1.0-30.0% of Na ₂ O components in terms of mass %, and the content of B ₂ O ₃ components It is 20.0% or less, has a refractive index (nd ) of 1.62 to 1.75, an Abbe number (ν _d ) of 30 to ₄₂ , and a partial dispersion ratio (θg, F) of 0.594 or less. In glasses containing SiO ₂ components and Nb ₂ O ₅ components, even when the content of B ₂ O ₃ components is reduced, a higher refractive index or a lower Abbe number within the desired range can be obtained (higher dispersion), and glass with lower partial dispersion ratio. Also, the second optical glass contains 10.0 to 70.0% of SiO ₂ components, 1.0 to 50.0% of Nb ₂ O ₅ components, and 1.0 to 25.0% of Na ₂ O components in mass %, and the mass ratio (Li ₂ O + Na ₂ O)/(ZrO ₂ ) is not less than 0.50, has a refractive index (n d ) of not less than 1.64 and not more than 1.70, an Abbe number (ν _d ) of not less than 31 and not more than 42, and a partial dispersion ratio (θg, _F ). In glass containing SiO ₂ and Nb ₂ O ₅ , especially when Na ₂ O is contained and the mass ratio (Li ₂ O+Na ₂ O)/(ZrO ₂ ) is large, desired Glasses with higher refractive index or lower Abbe number (higher dispersion) and lower partial dispersion ratio in the range. In addition, the third optical glass contains 10.0 to 70.0% of SiO ₂ components, 1.0 to 50.0% of Nb ₂ O ₅ components, 1.0 to 25.0% of Na ₂ O components, and 0.1 to 20.0% of Li ₂ O in mass %. It has a refractive index (n _d ) of not less than 1.62 and not more than 1.75, an Abbe number (ν _d ) of not less than 30 and not more than 40, and a partial dispersion ratio (θg, F) of not more than 0.594. In glass containing SiO ₂ components and Nb ₂ O ₅ components, especially even in the case of containing Na ₂ O components and Li ₂ O components, high or low refractive index within the desired range can be obtained. Glass with Abbe number (higher dispersion) and lower partial dispersion ratio. Therefore, the required higher refractive index (n _d ) and lower Abbe number (ν _d ) can be obtained, and the partial dispersion ratio (θg, F) is small, which reduces the chromatic aberration of the optical system Useful optical glass. In addition, due to the small specific gravity, it can contribute to the weight reduction of optical equipment. Due to the high transmittance of visible light, it can be preferably used for the purpose of transmitting visible light. Moreover, due to the low transition point of glass, It is also possible to obtain optical glass that can reduce the heating temperature during reheating and press molding. Hereinafter, embodiments of the optical glass of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be appropriately modified and implemented within the scope of the purpose of the present invention. Furthermore, there are cases where it is appropriate to omit the description of parts that are repeated in the description, but this does not limit the gist of the invention. [Glass Components] The composition ranges of the respective components constituting the optical glass of the present invention will be described below. In this specification, unless otherwise specified, the content of each component is set as the mass % of all oxide conversion compositions with respect to the total mass of glass. Here, the "composition in terms of oxides" refers to the assumption that oxides, composite salts, metal fluorides, etc. used as raw materials for the glass constituents of the present invention are all decomposed during melting and changed into oxides , the total mass of the generated oxides is set as 100% by mass, and the composition of each component contained in the glass is expressed. <Regarding essential components and optional components> The SiO ₂ component is an essential component that promotes stable glass formation and reduces devitrification (generation of crystals), which is not good as an optical glass. In particular, by setting the content of the SiO ₂ component to 10.0% or more, devitrification can be reduced without greatly increasing the partial dispersion ratio. In addition, devitrification or coloration during reheating can be reduced by this. Therefore, the content of the _SiO2 component is preferably 10.0% or more, more preferably more than 20.0%, more preferably more than 25.0%, more preferably more than 30.0%, and more preferably more than 30.0%. It is more than 32.0%, more preferably more than 34.0%, and more preferably more than 35.0%. On the other hand, by making the content of the SiO ₂ component 70.0% or less, the refractive index becomes difficult to decrease, thereby making it easy to obtain a desired high refractive index, and suppressing an increase in the partial dispersion ratio. In addition, this can suppress a decrease in the solubility of the glass raw material. Therefore, the content of the _SiO2 component is preferably set at 70.0% or less, more preferably set at less than 60.0%, more preferably set at less than 50.0%, further preferably set at less than 45.0%, and still more preferably set at less than 45.0%. It is more preferable to set it as less than 43.0%, and it is more preferable to set it as less than 40.0%. As the SiO ₂ component, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ and the like can be used as raw materials. The Nb ₂ O ₅ component is an essential component that can increase the refractive index of the glass and reduce the Abbe number and partial dispersion ratio by containing 1.0% or more. Therefore, the content of the Nb ₂ O ₅ component is preferably 1.0% or more, more preferably more than 4.0%, more preferably more than 7.0%, more preferably more than 10.0%, and more preferably To be more than 15.0%, more preferably more than 20.0%, more preferably more than 23.0%, more preferably more than 24.0%, more preferably more than 25.0%, and more preferably It is not set to exceed 26.0%. On the other hand, by setting the content of the Nb ₂ O ₅ component to 50.0% or less, the material cost of the glass can be reduced. Also, it can suppress the rise of the melting temperature during glass production, and reduce devitrification caused by excessive content of Nb ₂ O ₅ component. Therefore, the content of the Nb ₂ O ₅ component is preferably 50.0% or less, more preferably less than 40.0%, more preferably less than 35.0%, and still more preferably less than 31.0%. Furthermore, it is more preferable to set it as less than 30.0%. As the Nb ₂ O ₅ component, Nb ₂ O ₅ or the like can be used as a raw material. The Na ₂ O component is an essential component that can reduce the partial dispersion ratio of glass, improve reheat pressability, lower the glass transition point, and improve the solubility of glass raw materials by containing 1.0% or more. Therefore, the content of the _Na2O component is preferably 1.0% or more, more preferably more than 3.0%, more preferably more than 5.0%, more preferably more than 6.0%, and more preferably more than 6.0%. More than 8.5%, more preferably more than 10.0%, more preferably more than 11.0%, still more preferably more than 12.0%. On the other hand, by making the content of the Na ₂ O component 30.0% or less, the decrease in the refractive index of the glass can be suppressed, the chemical durability can hardly be deteriorated, and devitrification due to excessive content can be reduced. Therefore, the content of the _Na2O component is preferably 30.0% or less, more preferably 25.0% or less, still more preferably less than 20.0%, still more preferably less than 18.0%, and still more preferably less than 25.0%. It is more preferable to set it as less than 15.0%, and it is more preferable to set it as less than 13.0%. As a _Na2O component, _Na2CO3 , _NaNO3 , NaF, _Na2SiF6 etc. can be used _as _a raw material. When the B ₂ O ₃ component is contained in excess of 0%, it is an arbitrary component that promotes stable glass formation, reduces devitrification, and improves the solubility of glass raw materials. Therefore, the content of the B ₂ O ₃ component can also be preferably set to exceed 0%, more preferably set to exceed 1.0%, more preferably set to exceed 3.0%, further preferably set to exceed 4.0%, and furthermore It is more preferably more than 5.5%, more preferably more than 7.5%, and more preferably more than 10.0%. On the other hand, by making the content of the B ₂ O ₃ component 25.0% or less, a decrease in the refractive index or an increase in the Abbe number can be suppressed, and an increase in the partial dispersion ratio can be suppressed. Therefore, the content of _the _B2O3 component is preferably 25.0% or less, more preferably 20.0% or less, more preferably less than 20.0%, still more preferably less than 16.0%, and more preferably less than 20.0%. It is more preferable to set it as less than 15.0%, and it is more preferable to set it as less than 12.5%. For the B ₂ O ₃ component, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ ·10H ₂ O, BPO ₄ , and the like can be used as raw materials. The ratio (mass ratio) of the total amount of the Li ₂ O component and the Na ₂ O component to the content of the ZrO ₂ component is preferably 0.50 or more. Thereby, the solubility of glass raw material can be improved, the devitrification of glass can be reduced, and the reheating and pressurization property of glass can be improved. Therefore, the mass ratio (Li ₂ O+Na ₂ O)/(ZrO ₂ ) may preferably be 0.50 as the lower limit, more preferably 1.00 as the lower limit, further preferably 1.30 as the lower limit, and still more preferably In order to set 1.70 as the lower limit, it is more preferable to set 1.78 as the lower limit. On the other hand, regarding the upper limit of the mass ratio (Li ₂ O+Na ₂ O)/(ZrO ₂ ), it is preferable to set the upper limit to not reach the point of view of reducing the devitrification of the glass and improving the solubility of the glass raw material. 15.00, more preferably set as less than 12.00, more preferably set as less than 11.00. The _ZrO2 component is an arbitrary component that can increase the refractive index of the glass, lower the Abbe number, lower the partial dispersion ratio, and reduce devitrification when it contains more than 0%. In addition, devitrification or coloration during reheating can be reduced by this. Therefore, the content of the _ZrO2 component can also be preferably set to more than 0%, more preferably set to more than 1.0%, more preferably set to more than 1.5%, more preferably set to more than 3.0%, and more preferably In order to be more than 4.0%, it is more preferable to be more than 5.0%, and it is more preferable to be more than 7.0%. On the other hand, by making the content of the ZrO ₂ component 25.0% or less, devitrification can be reduced, and more homogeneous glass can be easily obtained. Therefore, the content of the _ZrO2 component is preferably set at 25.0% or less, more preferably set at less than 20.0%, more preferably set at less than 18.0%, more preferably set at less than 16.0%, and even more preferably set at less than 16.0%. It is more preferably less than 15.0%, more preferably less than 13.0%, still more preferably less than 10.0%, and still more preferably less than 8.0%. As the ZrO ₂ component, ZrO ₂ , ZrF ₄ , etc. can be used as raw materials. The Li ₂ O component is an optional component that reduces the partial dispersion ratio of glass, improves reheat pressability, lowers the glass transition point, and improves the solubility of glass raw materials when contained in excess of 0%. Especially in the third optical glass, Li ₂ O component can reduce the partial dispersion ratio of glass by containing 0.1% or more, can improve reheating and pressing properties, can lower the glass transition point, and can improve the solubility of glass raw materials essential ingredients. The content of the _Li2O component in the optical glass of the present invention can also be preferably set at 0.1% or more, more preferably set at more than 0.5%, more preferably set at more than 1.0%, and more preferably set at more than 1.0%. 2.0%, and more preferably more than 2.5%. On the other hand, by making the content of the Li ₂ O component 20.0% or less, a decrease in the refractive index can be suppressed, chemical durability can hardly deteriorate, and devitrification due to excessive content can be reduced. Therefore, the content of the _Li2O component is preferably 20.0% or less, more preferably less than 10.0%, more preferably less than 8.0%, still more preferably less than 5.0%, and more preferably less than 5.0%. It is more preferable to set it as less than 3.0%, and it is more preferable to set it as less than 1.4%. As a _Li2O component _, _Li2CO3 , _LiNO3 , LiF, etc. can be used as a raw material. The K ₂ O component is an arbitrary component that lowers the refractive index, improves the solubility of glass raw materials, and lowers the glass transition point when contained in excess of 0%. On the other hand, by making the content of the K ₂ O component 20.0% or less, the increase in the partial dispersion ratio can be suppressed, devitrification can be reduced, and chemical durability can be hardly deteriorated. In addition, it is possible to suppress a decrease in reheat and press formability. Therefore, the content of the K ₂ O component is preferably set to 20.0% or less, more preferably set to 15.0% or less, still more preferably set to less than 15.0%, still more preferably set to less than 12.0%, still more preferably Preferably, it is less than 11.0%, more preferably less than 10.0%, more preferably less than 8.0%, more preferably less than 5.0%, and more preferably less than 5.0%. 3.0%. As the K ₂ O component, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ , etc. can be used as raw materials. The TiO ₂ component is an arbitrary component that increases the refractive index, lowers the Abbe number, and reduces devitrification when contained in excess of 0%. On the other hand, by setting the content of the TiO ₂ component to 20.0% or less, the coloring of the glass can be reduced and the internal transmittance can be improved. Moreover, since it becomes difficult to raise a partial dispersion ratio by this, a desired low partial dispersion ratio can be easily obtained. Therefore, the content of the _TiO2 component is preferably set at 20.0% or less, more preferably set at less than 15.0%, more preferably set at less than 10.0%, still more preferably set at less than 5.0%, and still more preferably set at less than 5.0%. It is more preferably less than 3.0%, more preferably less than 1.0%, and still more preferably less than 0.1%. TiO ₂ component can use TiO ₂ etc. as a raw material. The MgO component is an arbitrary component that can lower the melting temperature of glass when it contains more than 0%. On the other hand, by making the content of the MgO component 10.0% or less, the decrease in the refractive index or the increase in the Abbe's number can be suppressed, and devitrification can be reduced. Therefore, the content of the MgO component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, still more preferably less than 1.0%, and still more preferably It is set as less than 0.5%. As the MgO component, MgO, MgCO ₃ , MgF ₂ , etc. can be used as raw materials. When the CaO component is contained in excess of 0%, it is an arbitrary component that can reduce the material cost of glass, reduce devitrification, and improve the solubility of glass raw materials. On the other hand, by making the content of the CaO component 10.0% or less, the decrease in the refractive index, the increase in the Abbe number, and the increase in the partial dispersion ratio can be suppressed, and devitrification can be reduced. Therefore, the content of the CaO component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, still more preferably less than 1.9%, and still more preferably It is set as less than 0.5%. CaO component can use _CaCO3 , _CaF2 etc. as a raw material. The SrO component is an optional component that can reduce the devitrification of glass and increase the refractive index when it contains more than 0%. In particular, by setting the content of the SrO component to 10.0% or less, the increase in Abbe's number can be suppressed, and the deterioration of chemical durability can be suppressed. Therefore, the content of the SrO component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. As the SrO component, Sr(NO ₃ ) ₂ , SrF ₂ , or the like can be used as a raw material. BaO component is any component that can reduce devitrification of glass, increase the refractive index, improve the solubility of glass raw materials, and reduce the material cost of glass compared with other alkaline earth components when it contains more than 0%. Moreover, it is also a component which can suppress the fall of reheat press formability. On the other hand, by making content of a BaO component 20.0 % or less, the raise of Abbe's number can be suppressed, and deterioration of chemical durability, or devitrification can be suppressed. Therefore, the content of the BaO component is preferably 20.0% or less, more preferably less than 15.0%, more preferably less than 10.0%, and still more preferably less than 5.0%. As a BaO component, _BaCO3 , Ba( _NO3 ) ₂ etc. can be used as a raw material. The Ta ₂ O ₅ component is an arbitrary component that increases the refractive index, lowers the partial dispersion ratio, and reduces devitrification of the glass when contained in excess of 0%. On the other hand, by setting the content of the Ta ₂ O ₅ component to 10.0% or less, the amount of the Ta ₂ O ₅ component used as a rare mineral resource is reduced, and the glass becomes easier to melt at a lower temperature, so it can be reduced. Material cost or production cost of glass. In addition, devitrification of glass and increase in Abbe's number due to excessive content of the Ta ₂ O ₅ component can be reduced by this. Therefore, the content of _the _Ta2O5 component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. Furthermore, it is more preferable to set it as less than 0.5%. In particular, from the viewpoint of reducing the material cost of glass, the content of the Ta ₂ O ₅ component may be reduced to less than 0.1%. As _a _Ta2O5 component _, _Ta2O5 etc. can be used as a raw material. The La ₂ O ₃ component, the Gd ₂ O ₃ component, the Y ₂ O ₃ component, and the Yb ₂ O ₃ component are arbitrary components that can increase the refractive index and reduce the partial dispersion ratio by containing at least any one of them exceeding 0%. . On the other hand, by making content of a _La2O3 component 10.0% or less, increase of Abbe's number can be suppressed, _specific gravity can be made small, and devitrification can be reduced. Therefore, the content of the La ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. Moreover, by making content of a _Y2O3 component 20.0% or less, increase of Abbe's number can be suppressed, _specific gravity can be made small, and devitrification can be reduced. Therefore, the content of the Y ₂ O ₃ component is preferably 20.0% or less, more preferably less than 10.0%, more preferably less than 5.0%, and still more preferably less than 3.0%. Also, by setting the respective contents of the Gd ₂ O ₃ component and the Yb ₂ O ₃ component to 10.0% or less, an increase in Abbe's number can be suppressed, specific gravity can be reduced, devitrification can be reduced, and material cost can be reduced. Therefore, the content of each of the Gd ₂ O ₃ component and the Yb ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and more preferably less than 3.0%. Let it be less than 1.0%. La ₂ O ₃ components, Gd ₂ O ₃ components, Y ₂ O ₃ components and Yb ₂ O ₃ components can use La ₂ O ₃ , La(NO ₃ ) ₃・XH ₂ O (X is an arbitrary integer), Y ₂ O ₃ , YF ₃ , Gd ₂ O ₃ , GdF ₃ , Yb ₂ O ₃ , etc. are used as raw materials. The P ₂ O ₅ component is an arbitrary component that can reduce the devitrification of glass when contained in excess of 0%. On the other hand, devitrification due to excessive content of the P ₂ O ₅ component can be reduced by making the content of the P ₂ O ₅ component 10.0% or less. Therefore, the content of the P ₂ O ₅ component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. For the P ₂ O ₅ component, Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ , etc. can be used as raw materials. The GeO ₂ component is an arbitrary component that can increase the refractive index and reduce devitrification when contained in excess of 0%. On the other hand, by setting the content of the GeO ₂ component to 10.0% or less, the amount of the expensive GeO ₂ component used can be reduced, thereby reducing the material cost of the glass. Therefore, the content of the GeO ₂ component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 1.0%. GeO ₂ component can use GeO ₂ etc. as a raw material. Al ₂ O ₃ components and Ga ₂ O ₃ components are arbitrary components that can improve chemical durability and reduce devitrification of glass when at least any one of them is contained in excess of 0%. On the other hand, by making the content of the Al ₂ O ₃ component 15.0% or less, devitrification due to excessive content can be reduced. Therefore, the content of the Al ₂ O ₃ component is preferably 15.0% or less, more preferably less than 8.0%, more preferably less than 5.0%, and still more preferably less than 3.0%. Moreover, devitrification by excessive content can be reduced by making content of a _Ga2O3 component 10.0% _or less. Therefore, the content of the Ga ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%. _Al2O3 component and _Ga2O3 _component can use _Al2O3 , _Al (OH) ₃ , AlF3, _Ga2O3 _, _Ga (OH) ₃ etc. as a raw _material . The WO ₃ component is an arbitrary component that can increase the refractive index, lower the Abbe number, reduce the devitrification of glass, and improve the solubility of glass raw materials when it contains more than 0%. On the other hand, by making the content of the WO ₃ component 10.0% or less, it is difficult to increase the partial dispersion ratio of the glass, and it is possible to reduce the coloring of the glass and improve the internal transmittance. Therefore, the content of the WO ₃ component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. The WO ₃ component can use WO ₃ etc. as a raw material. The Bi ₂ O ₃ component is an optional component that increases the refractive index to lower the Abbe number and lowers the glass transition point when contained in excess of 0%. On the other hand, by making the content of the Bi ₂ O ₃ component 10.0% or less, it is possible to make it difficult to increase the partial dispersion ratio, reduce coloring of the glass, and increase the internal transmittance. Therefore, the content of the Bi ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, more preferably less than 3.0%, and still more preferably less than 1.0%. As _a _Bi2O3 component _, _Bi2O3 etc. can be used as a raw material. ZnO component is an arbitrary component that can reduce devitrification of the glass, lower the partial dispersion ratio, and lower the glass transition point when the ZnO component is contained more than 0%. On the other hand, by making content of a ZnO component 30.0% or less, devitrification and coloring at the time of reheating of glass can be reduced, and chemical durability can be improved. Therefore, the content of the ZnO component is preferably at most 30.0%, more preferably less than 20.0%, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably It is less than 3.0%, more preferably less than 2.0%, and more preferably less than 1.0%. As a ZnO component, ZnO, _ZnF2 , etc. can be used as a raw material. The TeO ₂ component is an arbitrary component that can increase the refractive index, lower the partial dispersion ratio, and lower the glass transition point when it contains more than 0%. On the other hand, by reducing the content of the TeO ₂ component to 15.0% or less, the coloring of the glass can be reduced and the internal transmittance can be improved. Also, by reducing the use of the expensive _TeO2 component, a lower material cost glass can be obtained. Therefore, the content of the _TeO2 component is preferably set at 15.0% or less, more preferably set at less than 10.0%, more preferably set at less than 5.0%, still more preferably set at less than 3.0%, and still more preferably set at less than 3.0%. It is preferable to set it as less than 1.0%. TeO ₂ component can use TeO ₂ etc. as a raw material. The SnO ₂ component is an arbitrary component that can clarify (defoam) the molten glass and increase the visible light transmittance of the glass when it contains more than 0%. On the other hand, by setting the content of the SnO ₂ component to 5.0% or less, coloring of the glass due to reduction of the molten glass or devitrification of the glass can hardly occur. In addition, alloying of _SnO2 components and melting equipment (especially precious metals such as Pt) can be reduced, so that the life of melting equipment can be extended. Therefore, the content of the SnO ₂ component is preferably 5.0% or less, more preferably less than 3.0%, and still more preferably less than 1.0%. For the SnO ₂ component, SnO, SnO ₂ , SnF ₂ , SnF ₄ , etc. can be used as raw materials. The Sb ₂ O ₃ component is an arbitrary component that can clarify the glass when the content exceeds 0%. On the other hand, by setting the content of the Sb ₂ O ₃ component to 1.0% or less, it is difficult to cause excessive foaming when the glass is melted, so that the Sb ₂ O ₃ component and the melting equipment (especially precious metals such as Pt) ) are difficult to alloy. Therefore, the content of the Sb ₂ O ₃ component is preferably 1.0% or less as the upper limit, more preferably less than 0.5%, and still more preferably less than 0.1%. However, when the environmental impact of optical glass is considered important, the Sb ₂ O ₃ component may not be contained. For the Sb ₂ O ₃ component, Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ ·5H ₂ O, etc. can be used as raw materials. In addition, the component _which clarifies glass is not limited to the said _Sb2O3 component, The well-known clarifier in the field|area of glass manufacture, or these combinations can be used. The ratio (mass ratio) of the content of the SiO ₂ component to the total amount of the SiO ₂ component and the B ₂ O ₃ component may be 0.10 or more. Thereby, the increase of the Abbe's number of glass can be suppressed. Therefore, this mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) may also preferably set 0.10 as the lower limit, more preferably set 0.30 as the lower limit, further preferably set 0.50 as the lower limit, and even more preferably The lower limit is preferably 0.65, and more preferably 0.75 is the lower limit. On the other hand, the upper limit of the mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) can also be 1, but from the perspective of suppressing the rise of the glass transition point, reducing the devitrification of the glass, and improving the solubility of the glass raw material It is also preferable to set it as less than 1, more preferably set it as less than 0.98, more preferably set it as less than 0.95, still more preferably set it as less than 0.95, and still more preferably set it as less than 0.93 , and more preferably set to 0.90 or less, still more preferably set to 0.88 or less, still more preferably set to 0.83 or less, still more preferably set to 0.80 or less. The sum (mass sum) of Rn ₂ O components (wherein, Rn is one or more selected from the group consisting of Li, Na, and K) is preferably 1.0% or more and 30.0% or less. In particular, by setting this mass sum to 1.0% or more, the solubility of glass raw materials can be improved and the glass transition point can be lowered. Therefore, the total content of the Rn ₂ O components may be preferably 1.0% or more, more preferably more than 5.0%, more preferably more than 10.0%, still more preferably more than 12.0%. On the other hand, by making this mass sum 30.0% or less, the refractive index of glass can be hard to fall, and the devitrification at the time of glass formation can be reduced. Therefore, the total content of Rn ₂ O components is preferably at most 30.0%, more preferably at most 25.0%, more preferably at most 23.0%, even more preferably at most 21.0%, Furthermore, it is more preferable to set it as less than 20.0%, and it is still more preferable to set it as less than 18.0%. The mass ratio Li ₂ O/Rn ₂ O is preferably 0.01 or more. This reduces the partial dispersion ratio of the glass, improves reheating and pressurization properties, and lowers the glass transition point. Therefore, the mass ratio Li ₂ O/Rn ₂ O is preferably 0.01 or more, more preferably more than 0.05, more preferably more than 0.10, and still more preferably more than 0.14. On the other hand, regarding the upper limit of the mass ratio Li ₂ O/Rn ₂ O, from the viewpoint of reducing the devitrification of the glass, it is also preferably set to 0.60, more preferably 0.50, and more preferably set to 0.50. is 0.40. The sum (mass sum) of the RO components (where R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 25.0% or less. Thereby, the increase of the Abbe's number can be suppressed, and the devitrification of the glass caused by the excessive content of these components can be reduced. Therefore, the mass sum of the RO component is preferably set at 25.0% or less, more preferably set at less than 15.0%, more preferably set at less than 10.0%, still more preferably set at less than 5.0%, and still more preferably It is preferable to set it as less than 2.0%. The sum (mass sum) of Ln ₂ O ₃ components (wherein, Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is preferably 20.0% or less. Thereby, the devitrification of glass can be reduced, the increase of Abbe's number can be suppressed, and the material cost can be reduced. Therefore, the mass sum of the Ln ₂ O ₃ components is preferably 20.0% or less, more preferably less than 15.0%, more preferably less than 10.0%, and more preferably less than 5.0%. , more preferably less than 3.0%, more preferably less than 1.0%. <About components that should not be contained> Next, components that should not be contained in the optical glass of the present invention and components that are not preferable if contained are described. Other components can be added as needed within the range that does not impair the properties of the glass of the present invention. Among them, in addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, Lu, various transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo can be used alone or in combination When a small amount of each is contained, the glass is also colored and has the property of absorbing at a specific wavelength in the visible light range. Therefore, it is preferable to substantially not contain it, especially in optical glasses using wavelengths in the visible light range. Also, since lead compounds such as PbO and arsenic compounds such as As ₂ O ₃ are components with a high environmental load, it is desirable to substantially not contain them, that is, not contain them at all except unavoidable contamination. Furthermore, the various components of Th, Cd, Tl, Os, Be, and Se tend to be controlled and used as harmful chemical substances in recent years, not only in the manufacturing steps of glass, but also in the processing steps and post-production processes. Environmental measures are necessary. Therefore, in the case of emphasizing the impact on the environment, it is preferable not to include these substantially. [Manufacturing method] The optical glass of the present invention is produced as follows, for example. That is, it is produced by the following method: the above-mentioned raw materials are uniformly mixed in a manner that each component becomes within a specific content range, and the prepared mixture is put into a platinum crucible, a quartz crucible or an alumina crucible for rough melting, and then placed Put it into a gold crucible, platinum crucible, platinum alloy crucible or iridium crucible and melt it at a temperature range of 1100-1400°C for 3-5 hours, stir and homogenize it and perform defoaming, etc., then lower it to a temperature of 1000-1400°C Afterwards, finishing stirring is carried out to remove the veins, and the mixture is cast into a mold for slow cooling. In this case, it is preferable to use one with higher solubility as a glass raw material. Thereby, melting at a lower temperature or melting in a shorter time can be realized, so the productivity of the glass can be improved and the production cost can be reduced. Moreover, since volatilization of components and reaction with a crucible etc. are reduced, less colored glass can be easily obtained. <Physical Properties> The optical glass of the present invention has a relatively high refractive index and an Abbe number within a specific range. The lower limit of the refractive index ( _nd ) of the optical glass of the present invention is preferably 1.62, more preferably 1.63, still more preferably 1.64, and still more preferably 1.65. The upper limit of the refractive index may also be preferably 1.75, more preferably 1.74, further preferably 1.72, further preferably 1.70, further preferably 1.68. The Abbe number (ν _d ) of the optical glass of the present invention is preferably 42 or less, more preferably 40 or less, still more preferably 39 or less, still more preferably 38 or less. On the other hand, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 30 as the lower limit, more preferably 32 as the lower limit, further preferably 33 as the lower limit, and still more preferably 33 as the lower limit. 34 is set as the lower limit. The optical glass of the present invention having such a refractive index and Abbe's number is useful in optical design, especially high imaging characteristics can be realized, and at the same time, the miniaturization of the optical system can be realized, so the degree of freedom of optical design can be expanded. Here, the optical glass of the present invention preferably has a refractive index (nd) and an Abbe number (νd) satisfying the relationship of (‑0.012νd+2.04)≦nd≦(-0.012νd+2.16). In the glass of the specific composition in this invention, when refractive index (nd) and Abbe's number (νd) satisfy this relationship, the glass which is hard to cause devitrification can be obtained. Therefore, in the optical glass of the present invention, it is preferable that the refractive index (nd) and the Abbe number (νd) satisfy the relationship of nd≧(-0.012νd+2.04), more preferably satisfy nd≧(-0.012νd+2.05 ), and more preferably satisfy the relationship of nd≧(-0.012νd+2.06), and further preferably satisfy the relationship of nd≧(-0.012νd+2.08). On the other hand, in the optical glass of the present invention, it is preferable that the refractive index (nd) and the Abbe number (νd) satisfy the relationship of nd≦(-0.012νd+2.16), more preferably satisfy nd≦(-0.012νd+2 .14), and more preferably satisfy the relationship of nd≦(-0.012νd+2.13), and more preferably satisfy the relationship of nd≦(-0.012νd+2.12). The optical glass of the present invention has a relatively low partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably 0.594 as the upper limit, more preferably 0.592 as the upper limit, further preferably 0.590 as the upper limit, and even more preferably To set 0.588 as the upper limit. The lower limit of the partial dispersion ratio (θg, F) may also be preferably 0.570, more preferably 0.573, further preferably 0.575, further preferably 0.576, further preferably 0.577. In addition, the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably between (-0.00162×ν _d +0.630)≦(θg, F)≦ ₍ - 0.00162×ν _d +0.652). Thereby, an optical glass having a relatively low partial dispersion ratio (θg, F) can be obtained, so that the optical element formed from the optical glass can contribute to reducing the chromatic aberration of the optical system. Therefore, in the optical glass of the present invention, it is preferable that the partial dispersion ratio (θg, F) and the Abbe number (νd) satisfy the relationship of θg, F≧(-0.00162× _νd + 0.630), more preferably satisfy The relationship of θg, F≧(-0.00162×ν _d +0.632), and more preferably, the relationship of θg, F≧(-0.00162×ν _d +0.634). On the other hand, in the optical glass of the present invention, it is preferable that the partial dispersion ratio (θg, F) and the Abbe number (νd) satisfy the relationship of θg, F≦(-0.00162× _νd + 0.652), more preferably In order to satisfy the relationship of θg, F≦(-0.00162×ν _d +0.650), and further preferably satisfy the relationship of θg, F≦(-0.00162×ν _d +0.648), and further preferably satisfy the relationship of θg, F≦ The relationship of (-0.00162×ν _d +0.646) is more preferable to satisfy the relationship of θg, F≦(-0.00162×ν _d +0.643). Furthermore, in the above-mentioned relational expressions of the partial dispersion ratio (θg, F) and the Abbe number (νd), by specifying these relations using a straight line with the same slope as the standard line, it is possible to obtain A glass with a smaller partial dispersion ratio (θg, F). The optical glass of the present invention preferably has a relatively small specific gravity. More specifically, the optical glass of the present invention preferably has a specific gravity of 3.80 [g/cm ³ ] or less. Thereby, the mass of an optical element or an optical device using the same can be reduced, thereby contributing to weight reduction of an optical device. Therefore, the specific gravity of the optical glass of the present invention is preferably 3.80 as the upper limit, more preferably 3.50 as the upper limit, further preferably 3.30 as the upper limit, further preferably 3.10 as the upper limit, and still more preferably To set 3.00 as the upper limit. In addition, the specific gravity of the optical glass of this invention is about 2.50 or more, More specifically, it is 2.70 or more, More specifically, it is often 2.80 or more. The specific gravity of the optical glass of the present invention is measured according to the Japan Optical Glass Industry Association standard JOGIS05-1975 "Measurement method of specific gravity of optical glass". The optical glass of the present invention is preferably less colored. In particular, the wavelength (λ ₅ ) at which the optical glass of the present invention exhibits a spectral transmittance of 5% in a sample with a thickness of 10 mm is preferably 400 nm or less, more preferably 380 nm or less, and still more preferably 350 nm or less. Also, the wavelength (λ ₈₀ ) at which the optical glass of the present invention exhibits a spectral transmittance of 80% in a sample with a thickness of 10 mm is preferably 450 nm or less, more preferably 420 nm or less, and still more preferably 400 nm or less. In this way, the absorption end of the glass is located near the ultraviolet range, which can improve the transparency of the glass in the visible light range, so the optical glass can be preferably used as a material for optical components such as lenses. The optical glass of the present invention preferably has a glass transition point of 650°C or lower. Thereby, the glass is softened at a lower temperature, so the glass can be molded at a lower temperature. In addition, it is also possible to reduce the oxidation of the mold used for press molding and achieve a longer life of the mold. Therefore, the glass transition point of the optical glass of the present invention preferably sets 650°C as the upper limit, more preferably sets 620°C as the upper limit, further preferably sets 600°C as the upper limit, and further preferably sets 580°C as the upper limit. is the upper limit, and it is more preferable to set 550°C as the upper limit. Furthermore, the lower limit of the glass transition point of the optical glass of the present invention is not particularly limited, but the glass transition point of the optical glass of the present invention may also preferably set 460°C as the lower limit, more preferably set 480°C as the lower limit , and more preferably set 500°C as the lower limit. The optical glass of the present invention preferably has a yield point (At) of 720°C or lower. Yield point is one of the indexes showing the softening property of glass like glass transition point, and is an index showing the temperature close to the pressure forming temperature. Therefore, by using glass having a yield point of 720° C. or lower, press molding at a lower temperature can be realized, so that press molding can be performed more easily. Therefore, the yield point of the optical glass of the present invention is preferably 720°C as the upper limit, more preferably 700°C as the upper limit, further preferably 690°C as the upper limit, and further preferably 680°C as the upper limit. The upper limit is more preferably 660°C, more preferably 650°C, and still more preferably 630°C. Furthermore, the yield point of the optical glass of the present invention is not particularly limited, but it is also preferably 500°C as the lower limit, more preferably 530°C as the lower limit, and still more preferably 560°C as the lower limit. The optical glass of the present invention preferably has a smaller average linear expansion coefficient (α). In particular, the average linear expansion coefficient of the optical glass of the present invention is preferably 150×10 ^-7 K ^-1 as the upper limit, more preferably 120×10 ^-7 K ^-1 as the upper limit, and still more preferably 115×10 -7 K -1 as the upper limit. 10 ⁻⁷ K ⁻¹ is set as the upper limit, more preferably, 110×10 ⁻⁷ K ⁻¹ is set as the upper limit, and further preferably, 100×10 ⁻⁷ K ⁻¹ is set as the upper limit. Thereby, the total amount of expansion or contraction caused by the temperature change of the glass is reduced when the optical glass is press-formed by the forming mold. Therefore, it is possible to make the optical glass less likely to break during press molding, and it is possible to improve the productivity of optical elements. The optical glass of the present invention preferably has good reheating and pressing formability. More specifically, the optical glass of the present invention preferably does not cause devitrification and opalescence even before and after a reheating test (release test). Thereby, it is difficult to cause devitrification and coloring due to the reheating test assuming reheating and pressure processing, so that the light transmittance of the glass is hardly lost, so it is easy to perform reheating and pressure processing on the glass. The reheating treatment. That is, since an optical element having a complex shape can be manufactured by press molding, it is possible to realize optical element manufacturing with low manufacturing cost and good productivity. Here, the reheating test (release test) can be carried out by the following method: a test piece of 15 mm × 15 mm × 30 mm is placed on a concave refractory and placed in an electric furnace for reheating, starting from room temperature It took 150 minutes to raise the temperature to a temperature 80°C to 150°C higher than the transition temperature (Tg) of each sample (the temperature of falling into the refractory), keep it at this temperature for 30 minutes, cool to room temperature and take it out to the furnace In addition, after grinding the opposite sides to a thickness of 10 mm in a manner that can be observed inside, visually observe the ground glass sample. In addition, the presence or absence of devitrification and milky white before and after the reheating test (release test) can be confirmed visually, for example, "no devitrification and milky white" means, for example, the test after the reheating test (release test) The value obtained by dividing the transmittance of light (d-ray) with a wavelength of 587.56 nm of the sheet by the transmittance of d-ray of the test piece before the reheating test is about 0.80 or more. The optical glass of the present invention preferably has high chemical durability. More specifically, the optical glass of the present invention preferably has higher water resistance or acid resistance. Thereby, when the optical glass is polished, the blurring of the glass caused by the cleaning liquid or the polishing liquid can be reduced, so that the polishing process can be performed more easily. Furthermore, the water resistance and acid resistance of optical glass refers to the chemical durability (water resistance, acid resistance) according to the Japan Optical Glass Industry Association standard "Measurement method of chemical durability of optical glass" JOGIS06-2008, which is better It is grade 1-3, more preferably grade 1-2, still more preferably grade 1. The optical glass of the present invention is preferably less likely to cause devitrification during glass production. This suppresses a reduction in transmittance due to crystallization of the glass during glass production, etc., so that the optical glass can be preferably used for optical elements such as lenses that transmit visible light. In addition, as a scale showing the degree of difficulty in causing devitrification at the time of glass production, for example, a low liquidus temperature can be cited. [Preforms and Optical Elements] Formed glass bodies can be produced from the produced optical glass by compression molding methods such as reheat press molding or precision press molding. That is, a preform for press molding can be produced from optical glass, and the preform can be reheated and press-molded and then ground to produce a glass molded body, or for example, a preform produced by grinding can be precisely machined. Press molding is performed to produce a glass molded body. In addition, the method of manufacturing a glass molding is not limited to these methods. The glass molded body produced in this manner is useful for various optical elements, and among them, it is particularly suitable for use in optical elements such as lenses and lenses. Thereby, the color blur caused by the chromatic aberration of the transmitted light of the optical system provided with the optical element can be reduced. Therefore, when the optical element is used in a camera, an object to be photographed can be represented more accurately, and when the optical element is used in a projector, a desired image can be projected with higher definition. [Example] The composition, refractive index ( _nd ), Abbe number ( ν _d ), partial dispersion ratio (θg, F), spectral transmittance showing 5% and 80% wavelength (λ ₅ , λ ₈₀ ), glass transition point (Tg), yield point (At), average linear expansion coefficient ( The results of α) and specific gravity are shown in Tables 1-8. Here, embodiment (No.A1～No.A27) also can be used as the embodiment of the 1st optical glass, embodiment (No.B1～No.B11) also can be used as the embodiment of the 2nd optical glass, embodiment ( No.C1-No.C12) can also be used as an example of the third optical glass, but it is not limited thereto. Furthermore, the following examples are for illustration only, and are not limited thereto. The glasses in the examples are selected from the high-purity raw materials used in ordinary optical glasses such as corresponding oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and metaphosphoric acid compounds as the ingredients. The raw materials were weighed and mixed uniformly so as to become the ratio of the composition of each example shown in the table, and put into a platinum crucible, and the temperature range of 1100-1400°C was used in an electric furnace according to the difficulty of melting the glass raw material. After internal melting for 3 to 5 hours, stirring and homogenizing for defoaming, etc., the temperature was lowered to 1000 to 1400° C., stirring and homogenizing, poured into a mold, and slow cooling to produce glass. The refractive index (n _d ), Abbe number (ν _d ) and partial dispersion ratio (θg, F) of the glasses in the examples were measured according to the standard JOGIS01-2003 of Japan Optical Glass Industry Association. And, from the obtained values of the refractive index (n _d ) and Abbe's number (ν _d ), the intercept b when the slope a in the relational expression (n _d =-a×ν _d + b) is 0.012 was obtained. Also, from the obtained values of Abbe number (ν _d ) and partial dispersion ratio (θg, F), the slope a' in the relational expression (θg, F=-a'×ν _d +b') is calculated as 0.00162 Time intercept b'. In addition, the glass used for this measurement used the thing processed with the slow cooling furnace at the slow cooling temperature-fall rate at -25 degreeC/hr. The transmittance of the glass in the examples is measured according to JOGIS02 standard of Japan Optical Glass Industry Association. Furthermore, in the present invention, by measuring the transmittance of the glass, the existence and degree of the coloring of the glass can be obtained. Specifically, measure the spectral transmittance of 200-800 nm for a parallel abrasive product with a thickness of 10±0.1 mm according to JISZ8722, and obtain λ ₅ (the wavelength when the transmittance is 5%) and λ ₈₀ (the wavelength when the transmittance is 80%). wavelength). The glass transition point (Tg) and yield point (At) of the glass in the embodiment are determined by measuring the relationship between the temperature and the elongation of the sample according to the Japanese Optical Glass Industry Association standard JOGIS08-2003 "Measurement method for thermal expansion of optical glass" obtained from the thermal expansion curve. The average coefficient of linear expansion (α) of the glass in the examples is based on the Japanese Optical Glass Industry Association Standard JOGIS08-2003 "Measurement Method for Thermal Expansion of Optical Glass", and the average linear expansion coefficient at 100-300°C is obtained. The specific gravity of the glass in the examples was measured according to the Japan Optical Glass Industry Association standard JOGIS05-1975 "Measurement method of specific gravity of optical glass". [Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

As shown in these tables, the partial dispersion ratio (θg, F) of the optical glass of the examples is 0.594 or less, more specifically, 0.593 or less, which is within a desired range. In particular, the partial dispersion ratio (θg, F) of the optical glasses of Examples (No.B1 to No.B11) was 0.590 or less. Here, the partial dispersion ratio (θg, F) and Abbe number (νd) of the optical glass of the embodiment of the present invention satisfy (-0.00162×ν _d +0.630)≦(θg, F)≦(-0.00162×ν _d +0.652). In particular, the optical glass of the examples (No.C1-No.C12) satisfies the relationship of (θg, F)≦(-0.00162×ν _d +0.650). Moreover, the optical glass of the Example (No.B1-No.B11) satisfies the relationship of (θg, F)≦(-0.00162×ν _d +0.647). Furthermore, the relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) of the glass in the embodiment of the present application is as shown in FIG. 2 . Therefore, it is shown that the optical glass of the embodiment of the present invention has a smaller partial dispersion ratio (θg, F). All the optical glasses of the examples of the present invention have a refractive index ( _nd ) of 1.62 or more, more specifically, 1.64 or more, which is within a desired range. In particular, the refractive index ( _nd ) of the optical glass of the Examples (No.C1-No.C12) is 1.66 or more. Moreover, the refractive index ( _nd ) of the optical glass of this invention is 1.75 or less. In particular, the refractive index ( _nd ) of the optical glass of the examples (No.B1 to No.B11) is 1.68 or less. In addition, the optical glasses of the examples of the present invention all have an Abbe number (ν _d ) of 30 or more, and the Abbe number (ν _d ) of 42 or less, more specifically, 41 or less, which is within a desired range . In particular, the Abbe number (ν _d ) of the optical glass of the examples (No.A1 to No.A27, No.B1 to No.B11) is 34 or more. On the other hand, the Abbe's number (ν _d ) of the optical glass of the Examples (No.C1 to No.C12) was 39 or less. Here, the refractive index (nd) and Abbe number (νd) of the optical glass of the embodiment of the present invention satisfy the relationship of (‑0.012νd+2.04)≦nd≦(-0.012νd+2.16). More specifically, Satisfy the relationship of (‑0.012νd＋2.08)≦nd≦(-0.012νd＋2.16). In particular, the refractive index (nd) and Abbe number (νd) of the optical glass of the examples (No.A1-No.A27) satisfy the relationship of (-0.012νd+2.08)≦nd≦(-0.012νd+2.13). In addition, the refractive index (nd) and Abbe's number (νd) of the optical glasses of Examples (No.B1 to No.B11) satisfy the relationship of (-0.012νd+2.08)≦nd≦(-0.012νd+2.11). In addition, the refractive index (nd) and Abbe's number (νd) of the optical glass of the examples (No.C1 to No.C12) satisfy the relationship of (-0.012νd+2.09)≦nd≦(-0.012νd+2.16). Furthermore, the relationship between the refractive index (nd) and the Abbe number (νd) of the glass in the embodiment of the present application is as shown in FIG. 3 . Therefore, it is shown that the optical glass of the example is an optical glass whose refractive index ( _nd ) and Abbe number (ν _d ) are within the desired range and whose partial dispersion ratio (θg, F) is small. In addition, the λ ₅ (wavelength when the transmittance is 5%) of the optical glasses of the examples are all 400 nm or less, more specifically, 350 nm or less. In particular, the λ ₅ (wavelength at 5% transmittance) of the optical glasses of the examples (No.B1 to No.B11) were all 340 nm or less. In addition, the λ ₈₀ (wavelength at which the transmittance is 80%) of the optical glasses of the examples is all 450 nm or less, more specifically, 440 nm or less. In particular, the λ ₈₀ (wavelength at which the transmittance is 80%) of the optical glasses of the examples (No.B1-No.B11) are all 390 nm or less. In addition, the λ ₈₀ (wavelength when the transmittance is 80%) of the optical glasses of Examples (No.C1 to No.C12) were all 420 nm or less. Therefore, it also shows that the optical glass of the embodiment has higher transmittance to visible light and less coloration. Moreover, the specific gravity of the optical glass of an Example is 3.80 or less, and more specifically, it is 3.60 or less, and it is in the desired range. Especially the specific gravity of the optical glass of an Example (No.A1-No.A27) is 3.30 or less. Moreover, the specific gravity of the optical glass of an Example (No.B1-No.B11) is 3.00 or less. Moreover, the glass transition point of the optical glass of an Example is 650 degreeC or less, More specifically, it is 630 degreeC or less. In particular, the glass transition point of the optical glass of the examples (No.B1 to No.B11) is 600°C or lower. Moreover, the glass transition point of the optical glass of an Example (No.C1-No.C12) is 550 degreeC or less. Moreover, the yield point of the optical glass of an Example was all 700 degrees C or less, and it was in the desired range. In particular, the yield point of the optical glass of the examples (No.B1 to No.B11) is 670°C or lower. Moreover, the yield point of the optical glass of an Example (No.C1-No.C12) is 620 degreeC or less. It is speculated that the glass can be molded at a lower temperature. In addition, the average linear expansion coefficient (α) of the optical glass of the examples is not more than 150×10 ^-7 K ^-1 , more specifically, not more than 140×10 ^-7 K ^-1 , which is within a desired range. In particular, the average coefficient of linear expansion (α) of the optical glass of Examples (No.B1 to No.B11, No.C1 to No.C12) is 110×10 ^-7 K ^-1 or less. Furthermore, a lens preform was formed using the optical glass of the embodiment, and the lens preform was press-molded. As a result, various lens shapes could be processed without causing devitrification or opalescence. Above, the present invention has been described in detail for the purpose of illustration, but this embodiment is not for the purpose of illustration only. It should be understood that various changes can be made by the practitioners without departing from the spirit and scope of the present invention.

圖1係表示於部分分散比(θg，F)為縱軸且阿貝數(ν_d )為橫軸之正交座標中所表示之標準線之圖。圖2係表示關於本案之實施例之部分分散比(θg，F)與阿貝數(ν_d )之關係之圖。圖3係表示關於本案之實施例之折射率(nd)與阿貝數(ν_d )之關係之圖。Fig. 1 is a graph showing standard lines expressed in orthogonal coordinates with partial dispersion ratio (θg, F) on the vertical axis and Abbe's number (ν _d ) on the horizontal axis. Fig. 2 is a graph showing the relationship between the partial dispersion ratio (θg, F) and Abbe's number (ν _d ) in the examples of the present invention. Fig. 3 is a graph showing the relationship between the refractive index (nd) and Abbe's number (ν _d ) in the examples of the present invention.

Claims

An optical glass containing, by mass %, 10.0% to 70.0% of SiO ₂ components, more than 5.5% to less than 12.5% of B ₂ O ₃ components, and more than 24.0% to 30.37% of Nb ₂ O ₅ composition, and 1.0% to 30.0% of Na ₂ O components, and the mass ratio Li ₂ O/Rn ₂ O is 0.01 or more, has a refractive index ( _nd ) of 1.62 to 1.75, and a ratio of 30 to 42 Abbe number (ν _d ), and partial dispersion ratio (θg, F) below 0.594.

The optical glass according to claim 1, wherein the mass ratio (Li ₂ O+Na ₂ O)/(ZrO ₂ ) is 0.50 or more.

The optical glass according to Claim 1, wherein the content of Li ₂ O is 20.0% or less in mass %.

The optical glass according to claim 1, wherein the mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) is 0.50 or more.

The optical glass according to claim 1, wherein the mass ratio (SiO ₂ )/(SiO ₂ +B ₂ O ₃ ) is 0.90 or less.

Such as the optical glass of Claim 1, wherein the content of _ZrO2 is 25.0% or less in mass %.

Such as the optical glass of claim item 1, which is 0~20.0% _K2O composition 0~20.0% _TiO2 composition 0~10.0% MgO composition 0~10.0% CaO composition 0~10.0% in mass % % SrO composition 0~20.0% BaO composition 0~10.0% Ta ₂ O ₅ composition 0~10.0% La ₂ O ₃ composition 0~10.0% Gd ₂ O ₃ composition 0~20.0% Y ₂ O ₃ Composition 0~10.0% Yb ₂ O ₃ Composition 0~10.0% P ₂ O ₅ Composition 0~10.0% GeO ₂ Composition 0~15.0% Al ₂ O ₃ Composition 0~10.0% Ga ₂ O ₃ composition 0 ~10.0% WO ₃ composition 0~10.0% Bi ₂ O ₃ composition 0~30.0% ZnO composition 0~15.0% TeO ₂ composition 0~5.0% SnO ₂ composition 0~1.0% Sb ₂ O ₃ composition .

The optical glass according to Claim 1, wherein the mass sum of Rn ₂ O components (wherein, Rn is one or more selected from the group consisting of Li, Na, and K) is not less than 1.0% and not more than 30.0%.

The optical glass according to Claim 1, wherein the mass sum of the RO components (where R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is 25.0% or less.

The optical glass according to Claim 1, wherein the mass sum of Ln ₂ O ₃ components (wherein, Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) is 20.0% or less.

A preform for grinding and/or precision press molding, comprising the optical glass according to any one of Claims 1 to 10.

An optical element comprising the optical glass according to any one of claims 1 to 10.