JP5761549B2 - Optical glass - Google Patents

Description

  The present invention relates to an optical glass excellent in transmittance in the visible range and suitable for various uses such as an optical lens.

  Optical lenses for CD, MD, DVD, and other optical disc systems, imaging lenses for digital cameras, video cameras, camera-equipped mobile phones, and other lenses such as transmission / reception lenses used for optical communications are aspherical lenses. Is widely used. These glass materials for lenses are required to have a high transmittance in the visible region (particularly around 400 nm). In addition, as an optical characteristic that contributes to a reduction in the thickness of a camera or the like, a refractive index of 1.5 to 1.8 and an Abbe number νd of about 30 to 70 are required.

These glasses are produced through a refining process by melting a raw material batch using, for example, a platinum melting container. Here, a fining agent such as Sb ₂ O ₃ is used to float fine dust bubbles remaining in the melt glass in the fining step (see, for example, Patent Documents 1 and 2).

JP 2007-176748 A JP 2007-169086 A

Sb ₂ O ₃ tends to be restricted in recent years due to environmental concerns. However, when the amount of Sb ₂ O ₃ added is reduced, there is a problem that the visible region transmittance particularly near 400 nm is greatly reduced.

The present invention, while reducing the Sb ₂ O ₃ content, and an object thereof is to provide an optical glass which can maintain a high transmittance in the visible region.

As a result of various investigations, the present inventor has found that in optical glass containing SiO _{2 in an amount} of 35% or more, the decrease in the visible region transmittance when the amount of Sb ₂ O ₃ added is reduced from the melting instrument or the like into the glass. It was ascertained that this was caused by mixed Pt ions. Specifically, as will be described later, the redox state of Pt ions is controlled by appropriately adjusting the mass ratio of Fe ₂ O ₃ functioning as an oxidant and the total Pt content. The present inventors have found that it is possible to suppress a decrease in rate, and propose as the present invention.

That is, the present invention is an optical glass containing, by mass%, SiO ₂ 35% or more, Sb ₂ O ₃ less than 50 ppm, Fe ₂ O ₃ less than 30 ppm as a composition, (Fe ₂ O ₃ content / total Pt The value of (content) is 5.5-14, It is related with the optical glass characterized by the above-mentioned.

The valence of Pt ions changes under the influence of other elements present in the glass melt. In this case, the redox reaction is represented by the following formula.
Pt ⁴⁺ + O ²⁻ ⇔ Pt ²⁺ + 1 / 2O ₂

In the formula, Pt ⁴⁺ represents an oxidation state of Pt, and Pt ²⁺ represents a reduction state of Pt. Since Pt has different wavelengths for absorbing light in the oxidized state and the reduced state, the transmittance in the visible region changes depending on the redox state of the glass melt. Specifically, Pt ⁴⁺ has an absorption in the ultraviolet region and thus does not affect the transmittance in the visible region, but Pt ²⁺ has an absorption in the visible region, so that the transmittance particularly near 400 nm tends to decrease. Become.

The redox state of the glass melt may be greatly influenced by an oxide that functions as an oxidant due to a change in valence. For example, Sb ₂ O ₃ added as a fining agent has trivalent and pentavalent valences, and releases oxygen when changing from pentavalent to trivalent, and also functions as an oxidizing agent. Therefore, when the amount of Sb ₂ O ₃ is relatively large, Pt ions are likely to be in an oxidized state (Pt ⁴⁺ ) and absorb in the ultraviolet and do not affect the visible range. However, if the amount of Sb ₂ O ₃ added is reduced, Pt tends to be in a reduced state (Pt ²⁺ ), and the transmittance in the visible range is likely to decrease.

Therefore, When checking element suitable for valence adjustment of Pt ions, it was found that also contain a Fe ₂ O ₃ is an oxide which functions as an oxidizing agent is suitable. Furthermore, it was found that by limiting the value of (Fe ₂ O ₃ content / total Pt content) to the above range, Pt ions can be effectively shifted to an oxidized state, and a decrease in visible transmittance can be suppressed. .

Incidentally, Fe ₂ O ₃ is to have an absorption near a wavelength of 300 nm, excessive and the inclusion of absorption edge is shifted to the long wavelength side, the transmittance in the visible region as a result tends to decrease. Therefore, in the present invention, by limiting the content of Fe ₂ O ₃ to less than 30 ppm, the reduction in visible region transmittance due to Fe ₂ O ₃ is suppressed as much as possible.

As described above, the optical glass of the present invention can maintain high transmittance in the visible region even when the content of Sb ₂ O ₃ that is a fining agent is relatively small.

  Secondly, the optical glass of the present invention is characterized in that the absorption edge of transmittance measured at a thickness of 10 mm is 310 nm or less.

  If the absorption edge of the transmittance measured at a thickness of 10 mm exists on the short wavelength side of 310 nm or less, it can be said that the glass is particularly excellent in the visible region transmittance around 400 nm.

Third, the optical glass of the present invention is characterized in that a difference ΔT (= T ₇₀₀ −T ₃₈₀ ) between a transmittance T _{700 at 700} nm and a transmittance T ₃₈₀ at ₃₈₀ nm measured at a thickness of 10 mm is 12% or less. To do.

  If the ΔT is 12% or less, it can be said that the glass has little absorption in the vicinity of a wavelength of 400 nm and has excellent visible region transmittance.

  Fourthly, the optical glass of the present invention has a basicity of 5.5 or more.

As will be described later, when the basicity of the glass is large, Fe ions are likely to exist in the state of Fe ³⁺ having an oxidizing power with respect to Pt, and even if the content of Fe ₂ O ₃ is small, Pt ions are effectively removed. Can be oxidized.

Fifth, the optical glass of the present invention is characterized by further containing 7% or more of B ₂ O ₃ and / or 1% or more of Al ₂ O ₃ .

  With this configuration, an optical glass having a basicity of 5.5 or more is easily obtained.

  Sixth, the optical glass of the present invention is characterized in that the total Pt content is 15 ppm or less.

By limiting the total Pt content to 15 ppm or less, the content of Pt ²⁺ ions can be reduced as a result, and the visible region transmittance can be improved.

  Seventh, the optical glass of the present invention is used for optical lens applications.

  Eighth, the optical glass of the present invention is used for mold press molding applications.

Sample No. in the examples. It is a graph which shows the transmittance | permeability curve of 1-3 glass samples.

The optical glass of the present invention is an optical glass containing, by mass%, SiO ₂ 35% or more, Sb ₂ O ₃ less than 50 ppm, Fe ₂ O ₃ less than 30 ppm in terms of composition, (Fe ₂ O ₃ content / total The value of (Pt content) is 5.5 to 14. In the following description, “%” means “% by mass” unless otherwise specified.

In the present invention, since Sb ₂ O ₃ is an environmental load substance, its content is limited to less than 50 ppm, preferably 30 ppm or less, 10 ppm or less, and particularly preferably 5 ppm or less. In addition, although it does not specifically limit about a minimum, You may make it contain 1 ppm or more for the purpose of exhibiting the function to oxidize Pt ion, and the function as a clarifier.

Since Fe ₂ O ₃ has an absorption of Fe itself in the vicinity of 300 nm, if its content is too large, it leads to a decrease in visible region transmittance. Therefore, the content of Fe ₂ O ₃ is preferably less than 30 ppm, particularly preferably 20 ppm or less. The lower limit is not particularly limited, Fe ₂ O ₃ is for a mixed easily component as an impurity from glass raw materials or the melting vessel or the like, in practice it is 1ppm or more.

In the present invention, the Pt content is preferably 15 ppm or less, 10 ppm or less, and particularly preferably 5 ppm or less. If the Pt content exceeds 15 ppm, the Pt ²⁺ content tends to increase as a result, and the visible region transmittance tends to decrease. The lower limit is not particularly limited, but is practically 1 ppm or more.

In the present invention, an optical glass having a high transmittance in the visible region can be obtained by strictly limiting the ratio of Pt and Fe ₂ O ₃ having an action of oxidizing Pt. Specifically, the value of (Fe ₂ O ₃ content / total Pt content) is preferably 5.5 to 14, 5.5 to 13, particularly 6 to 8. By limiting the value of (Fe ₂ O ₃ content / total Pt content) to this range, Pt ions can be effectively shifted to the oxidized state. As a result, absorption near 400 nm can be reduced as much as possible, and the visible region transmittance can be improved.

In the glass, the Fe component exists as Fe ³⁺ or Fe ²⁺ . Comparing the oxidizing powers of Fe ²⁺ , Fe ³⁺ , and Pt ²⁺ ions, Fe ²⁺ <Pt ²⁺ <Fe ³⁺ , and Fe ³⁺ can oxidize Pt ²⁺ , but Fe ²⁺ has no effect of oxidizing Pt ²⁺ .

Whether the Fe component exists as Fe ²⁺ or Fe ³⁺ in the glass depends on the ability of the cation to attract oxygen in the glass, that is, the basicity.

In the present invention, the basicity is defined as (total number of moles of oxygen atoms / total number of positive field strength) × 100. The field strength (hereinafter referred to as FS) in the equation is obtained by the following equation.
F. S. = Z / r ²

  Z represents an ionic valence, and r represents an ionic radius (Å). The coordination number and ionic valence of the elements in the glass change depending on the glass composition, and the numerical value of the ion radius changes accordingly. Therefore, in calculating an accurate basicity, it is preferable to appropriately select the ionic valence and ionic radius of each element according to the glass composition system. In the glass composition system of the present invention, it is appropriate to use the values of Table 1 for the values of Z and r.

If the basicity of the glass is large, Fe component is liable to exist in ^{Fe 3+} having oxidizing power for ^{Pt 2+,} even if a small _Fe 2 _{O 3} content is effective in the oxidation of ^{Pt 2+} . On the other hand, when the basicity of the glass is small, the Fe component is likely to be present as Fe ²⁺ , and the Pt ions are easily shifted to the reduced state.

  From the above viewpoints, the basicity of the optical glass of the present invention is preferably 5.5 or more, 6 or more, particularly 6.5 or more. The upper limit is not particularly limited, but if the basicity is too high, the glass is likely to be fused to the mold during mold press molding, so that it is 11 or less, 10.5 or less, particularly 9.5 or less. Preferably there is.

In the present invention, SiO ₂ is an essential component for constituting the glass skeleton. SiO ₂ is also a component that improves the weather resistance of glass, and has the effect of increasing the Abbe number next to B ₂ O ₃ . The content of SiO ₂ is 35% or more, preferably 36% or more, particularly preferably 42% or more. When the content of SiO ₂ is less than 35%, acid resistance and weather resistance tend to deteriorate. On the other hand, the upper limit of the SiO ₂ content is not particularly limited, but if it is too large, the refractive index is lowered, making it difficult to obtain desired optical characteristics. Further, the softening point tends to be high, and mold press molding tends to be difficult. Therefore, the content of SiO ₂ is preferably 60% or less, particularly 55% or less.

In addition to the above, the optical glass of the present invention preferably contains 7% or more of B ₂ O ₃ and / or 1% or more of Al ₂ O ₃ . Thereby, it becomes easy to achieve a basicity of 5.5 or more.

B ₂ O ₃ is a component that increases the Abbe number. The content of B ₂ O ₃ is preferably 7% or more, particularly preferably 8% or more. When the content of B ₂ O ₃ is less than 7%, the Abbe number decreases and it becomes difficult to obtain desired optical characteristics. On the other hand, the upper limit of the B ₂ O ₃ content is not particularly limited, but if it is too much, the acid resistance tends to decrease. Therefore, the content of B ₂ O ₃ is preferably 25% or less, particularly preferably 20% or less.

Al ₂ O ₃ is a component that improves the weather resistance of the glass. The content of Al ₂ O ₃ is preferably 1% or more, particularly preferably 3% or more. On the other hand, the upper limit of the Al ₂ O ₃ content is not particularly limited, but if it is too large, the viscosity of the glass tends to be high, and the clarity is likely to deteriorate, or mold press molding at low temperatures tends to be difficult. Therefore, the content of Al ₂ O ₃ is preferably 19% or less, particularly preferably 15% or less.

Further, the optical glass of the present invention includes R ′ ₂ O (R = Li, Na, K) 0 to 17%, RO (R = Ca, Sr, Ba) 0 to 25%, La ₂ O ₃ 7 to 20 %, ZrO ₂ 0-2.5% can be added.

The R ′ ₂ O component is a component that reduces the viscosity of the glass, and has an effect of maintaining good clarity even when the amount of Sb ₂ O ₃ is small. In addition, mold press molding at a low temperature is possible. In addition, by actively adding R ′ ₂ O, the basicity of the glass is easily increased, and the Fe component is likely to exist in the state of Fe ³⁺ . On the other hand, when it is contained in a large amount, the chemical durability is remarkably deteriorated, and the glass surface is easily deteriorated in the washing step. Also, the liquidus temperature rises and the working range is narrowed, which tends to adversely affect mass productivity. Therefore, the content of R ′ ₂ O is preferably 0 to 17%, 0.1 to 13%, particularly 3 to 12%.

Li ₂ O is a component that has a high effect of improving workability by lowering the melting temperature and softening point. The content of Li ₂ O is preferably 2 to 12%, particularly 3 to 10%. When the content of Li ₂ O is less than 2%, the melting temperature tends to be high and workability tends to be lowered. When the content of Li ₂ O is more than 12%, the phase separation becomes stronger, the liquidus temperature becomes higher, and the workability tends to deteriorate.

Na ₂ O is a component having an effect of improving workability by lowering the melting temperature and softening point, like Li ₂ O. However, if its content is too large, the more volatile compounds represented during glass melting with B _{2 O} 3 _{-Na 2 O,} there is a tendency that generation of striae is promoted. Therefore, the content of Na ₂ O is preferably 0 to 10%, particularly preferably 0.1 to 5%.

K ₂ O is a component having an effect of improving workability by lowering the melting temperature and softening point, like Li ₂ O. However, if its content is too large, the more volatile compounds represented during glass melting with B _{2 O} 3 _{-K 2 O,} there is a tendency that generation of striae is promoted. Therefore, the content of K ₂ O is preferably 0 to 10%, particularly preferably 0.1 to 5%.

The RO (R = Ca, Sr, Ba) component has the effect of lowering the viscosity of the glass in the same manner as the R ′ ₂ O component. However, when the content is too large, chemical durability tends to deteriorate. Therefore, the RO content is preferably 0 to 25%, 0 to 20%, particularly preferably 0.1 to 15%.

CaO is R 'is a large effect component to lower the softening point Following _{2 O,} R' can be enhanced weather resistance and acid resistance by replacing the _{2 O.} It also has the effect of increasing the refractive index. However, if the content is too large, the glass surface tends to be altered when exposed to a high temperature and humidity environment for a long period of time. Therefore, the content of CaO is preferably 0 to 15%, 0 to 10%, particularly preferably 0.5 to 10%.

  SrO, like BaO, is a component that improves weather resistance and increases the refractive index, and is a component that can improve the workability by lowering the liquidus temperature of the glass. However, if the content is too large, the glass surface tends to be altered when exposed to a high temperature and humidity environment for a long period of time. Accordingly, the SrO content is preferably 0 to 15%, particularly preferably 0.1 to 10%.

  BaO is a component that improves the weather resistance and increases the refractive index, and has the effect of improving workability by lowering the liquidus temperature of the glass. However, if the content is too large, the glass surface tends to be altered when exposed to a high temperature and humidity environment for a long period of time. Therefore, the content of BaO is preferably 0 to 25%, 3 to 25%, particularly 3 to 12%.

La ₂ O ₃ is a component that can lower the viscosity and improve the clarity while maintaining the chemical durability of the glass. However, if the content is too large, the refractive index tends to be higher than necessary. Therefore, the content of La ₂ O ₃ is preferably 7 to 20%, particularly 7 to 12%.

ZrO ₂ is a component that increases the refractive index. The content of ZrO ₂ is preferably 0 to 2.5%, particularly preferably 0.1 to 2%.

  Furthermore, the following components can be added to the optical glass of the present invention.

Gd ₂ O ₃ is a component that increases the refractive index without decreasing the Abbe number. However, when there is too much the content, it will become easy to devitrify. Therefore, the content of Gd ₂ O ₃ is preferably 0 to 15%, particularly preferably 0.1 to 10%.

TiO ₂ is a component that increases the refractive index and improves the weather resistance. However, since the reducing action on the Fe component is strong and the Fe ³⁺ ions are easily changed to Fe ²⁺ ions, the content is preferably as small as possible. Therefore, it is desirable that the content of TiO ₂ is 0.4% or less, 0.2% or less, and not particularly contained.

Nb ₂ O ₅ is an effective component for increasing the refractive index, but significantly reduces the Abbe number. Therefore, the content of Nb ₂ O ₅ is preferably 0 to 15%, particularly preferably 0.1 to 10%.

Bi ₂ O ₃ is a component that increases the refractive index. However, if the content is too large, the glass tends to be colored. Therefore, the content of Bi ₂ O ₃ is preferably 5% or less, particularly 3% or less.

P ₂ O ₅ is a component that lowers the liquidus temperature. However, when there is too much the content, it will become easy to phase-separate glass and the glass surface will become cloudy easily at the washing | cleaning process. Therefore, the content of P ₂ O ₅ is preferably 5% or less, particularly 3% or less.

The lead component (PbO), the arsenic component (As ₂ O ₃ ), and the F component (F ₂ ) should be substantially not introduced into the glass for environmental reasons. Therefore, in the present invention, it is preferable that these components are not substantially contained (specifically, each is less than 0.1%).

  In the optical glass of the present invention, the absorption edge of transmittance measured at a thickness of 10 mm is preferably 310 nm or less, particularly preferably 300 nm or less. If the absorption edge of the transmittance measured at a thickness of 10 mm exists on the short wavelength side of 310 nm or less, it can be said that the glass has particularly good visible region transmittance around 400 nm.

Further, as another index for evaluating the visible region transmittance, a difference ΔT (= T ₇₀₀ −T ₃₈₀ ) between a transmittance T _{700 at 700} nm and a transmittance T ₃₈₀ at ₃₈₀ nm measured at a thickness of 10 mm is 12% or less, In particular, it is preferably 10% or less. If ΔT satisfies this range, it can be said that the glass has good visible region transmittance particularly in the vicinity of 400 nm.

  The optical constant of the optical glass of the present invention is not particularly limited. For example, the refractive index nd is 1.5 to 1.8, particularly 1.55 to 1.7, and the Abbe number νd is 30 to 70, particularly 40 to 65. It is appropriately selected within the range.

  The glass transition point Tg of the optical glass of the present invention is preferably as low as possible because mold press molding becomes easier. Specifically, the glass transition point Tg is preferably 630 ° C. or lower, 600 ° C. or lower, particularly 550 ° C. or lower.

  Next, the optical glass of the present invention and a method for manufacturing an optical component such as an optical lens using the optical glass will be described.

  First, a glass material prepared to have a desired composition is melted in a melting container. The melting temperature is not particularly limited as long as it is a temperature at which homogeneous glass can be obtained, but is preferably 1150 to 1400 ° C., for example. Further, the melting time is preferably 2 hours or more, particularly 3 hours or more from the viewpoint of sufficiently promoting vitrification and clarification. However, the melting time is preferably 8 hours or less, and particularly preferably 5 hours or less, from the viewpoint of preventing coloring due to the melting of the Pt component into the glass.

  The depth of the glass melt in the melting container is preferably 30 mm or more, particularly 50 mm or more. If the glass melt depth is less than 30 mm, the glass productivity tends to be inferior. On the other hand, the upper limit of the depth of the glass melt is not particularly limited, but if it is too deep, it takes time for the bubbles to rise, and it is preferably 1 m or less, particularly 0.5 m or less.

  Subsequently, the molten glass is formed into a preform having a size capable of mold press molding. Further, the preform is subjected to mold press molding using a mold, processed into a desired shape, and then washed and dried to produce an optical component.

  As a method of forming a preform, it may be prepared by cutting out and polishing and washing a plate-like or lump-like glass piece into a predetermined shape, but a molten glass is continuously dropped onto a mold by a predetermined amount, It is preferable to use a droplet forming method in which molding is performed while cooling (after that, grinding, polishing, and washing are performed as necessary) because a preform having a desired shape can be easily produced.

  Hereinafter, although the optical glass of this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples.

  Tables 2 and 3 show examples (No. 1, 4, 6, 9) and comparative examples (No. 2, 3, 5, 7, 8, 10) of the present invention.

  Each sample was produced as follows.

Raw material powder having a purity of 99.9 to 99.999% was used as a raw material for components other than Fe ₂ O ₃ . Fe ₂ O ₃ was added with Fe ₂ O ₃ powder in addition to impurities mixed from the raw material powder of each component, and the content was adjusted.

  The glass raw material prepared so as to have the composition described in each table was put into a platinum crucible and melted at 1350 ° C. for 2 hours. Next, the molten glass was poured onto a carbon plate, cooled and solidified, and then annealed to produce a glass sample.

  The glass sample thus obtained was measured for Pt content, glass transition point, transmittance absorption edge and ΔT, refractive index, and Abbe number. The basicity was calculated from each glass composition. The results are shown in Tables 2 and 3.

The Pt content was measured as follows. First, the crushed glass sample was decomposed with a mixed acid (containing HF, HCLO ₄ , HNO ₃ , and HCl), then heated and evaporated to dryness to obtain a salt. Subsequently, nitric acid was added to the obtained salt and classified, followed by quantification with an ICP mass spectrometer.

  The glass transition point was determined from the intersection of a low temperature line and a high temperature line in the thermal expansion curve of the glass sample.

  The transmittance was measured as follows. First, a 10 mm thick double-side polished glass sample was prepared, and the transmittance at each wavelength was measured for the glass sample to prepare a transmittance curve. From the obtained transmittance curve, a wavelength at which the transmittance was 0.1% or less was read, and the wavelength was taken as an absorption edge. Further, transmittances at wavelengths of 700 nm and 380 nm were read, and the difference was taken as ΔT. Sample No. The transmittance curves of 1 to 3 are shown in FIG.

  The refractive index and Abbe number were measured by the V block method.

As is apparent from Tables 2 and 3, the examples No. Since the optical glasses of 1, 4, 6, and 9 satisfy the range of (Fe ₂ O ₃ content / total Pt content) of 5.5 to 14, the absorption edge is as small as 290 nm or less and visible. It can be seen that the transmittance in the region is excellent. On the other hand, sample No. which is a comparative example. In the optical glasses of 2, 5, and 8, (Fe ₂ O ₃ content / total Pt content) exceeded 14, and the absorption edge shifted to the longer wavelength side at 315 nm or more. Moreover, No. which is a comparative example. The optical glasses of ₃ , 7, and 10 had (Fe ₂ O ₃ content / total Pt content) smaller than 5.5 and ΔT increased to 13 or more. This means that there is absorption by Pt ²⁺ in the vicinity of 400 nm, and it is understood that the visible region transmittance is inferior.

  The optical glass of the present invention is an optical pickup lens for CD, MD, DVD, and other various optical disk systems, an imaging lens for a digital camera, a video camera, a camera-equipped mobile phone, and a transmission / reception lens used for optical communication. It is suitable as a glass material for lenses.

Claims (13)

It is an optical glass containing, by mass%, SiO ₂ 35% or more, Sb ₂ O ₃ less than 50 ppm, Fe ₂ O ₃ less than 30 ppm , and total Pt content of 1 ppm or more , (Fe ₂ O ₃ content / total An optical glass having a Pt content of 5.5 to 14.   The optical glass according to claim 1, wherein an absorption edge of transmittance measured at a thickness of 10 mm is 310 nm or less. 3. The optical glass according to claim 1, wherein a difference ΔT (= T ₇₀₀ −T ₃₈₀ ) between a transmittance T _{700 at 700} nm and a transmittance T ₃₈₀ at ₃₈₀ nm measured at a thickness of 10 mm is 12% or less. .   The optical glass according to any one of claims 1 to 3, wherein the basicity is 5 or more. _Further, B 2 _{O 3} 7% or more and / or optical glass according to any one of claims 1 to 4, characterized in that it contains _Al 2 _{O 3} 1% or more.   The optical glass according to claim 1, wherein the total Pt content is 15 ppm or less. In addition, R ’ ₂ O (R = Li, Na, K) 0-17%, RO (R = Ca, Sr, Ba) 0-25%, La ₂ O ₃   7-20%, ZrO ₂   The optical glass according to claim 1, comprising 0 to 2.5%. Li ₂ O 2-12%, Na ₂ O 0-10%, K ₂ The optical glass according to claim 7, containing O 0 to 10%, CaO 0 to 15%, SrO 0 to 15%, BaO 0 to 25%. Furthermore, Gd ₂ O ₃   0-15% TiO ₂   0.4% or less, Nb ₂ O ₅   0-15%, Bi ₂ O ₃   5% or less, P ₂ O ₅   The optical glass according to claim 1, comprising 5% or less. The optical glass according to any one of claims 1 to 9, which contains substantially no lead component, arsenic component and F component. The optical glass according to claim 1, wherein the refractive index nd is 1.5 to 1.8, and the Abbe number νd is 30 to 70. The optical glass according to any one of claims 1 to 11, characterized in that used in the optical lens applications. The optical glass according to any one of claims 1 to 12, characterized in that it is used in the press molding applications.