TWI541213B - Optical glass, preform and optical element - Google Patents

Description

Optical glass, preforms and optical components

The present invention relates to an optical glass, a preform, and an optical component.

Optical systems such as digital cameras or video cameras have size differences, but include blurs called aberrations. This aberration is classified into monochromatic aberration and chromatic aberration, and especially chromatic aberration strongly depends on the material properties of the lens used in the optical system.

Generally, the chromatic aberration is corrected by combining a low-dispersion convex lens and a highly-dispersed concave lens, but the combination can only correct the aberration between the red region and the green region, so that the aberration of the blue region remains. The aberration of the blue region that is not completely removed is referred to as a secondary spectrum. In order to correct the secondary spectrum, an optical design that supplements the movement of the g-line (435.835 nm) of the blue region must be performed. At this time, as an index of the optical characteristics that are attracting attention in the optical design, the partial dispersion ratio (θg, F) is used. In the optical system in which the above-mentioned low-dispersion lens and the highly-dispersed lens are combined, an optical material having a large partial dispersion ratio (θg, F) is used for the lens on the low dispersion side, and a partial dispersion ratio is used for the lens on the high dispersion side ( Θg, F) a smaller optical material whereby the secondary spectrum is well corrected.

The partial dispersion ratio (θg, F) is represented by the following formula (1).

Θg, F=(n _g -n _F )/(n _F -n _C ) (1)

(n _g means the refractive index of the spectrum of the glass to the source of mercury and the wavelength of 435.835 nm, n _F means the refractive index of the spectrum of the glass to the source of hydrogen and the wavelength of 486.13 nm, n _C means the glass to the source The refractive index of the spectral line of hydrogen and having a wavelength of 656.27 nm).

In the optical glass, there is a roughly linear relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) indicating the partial dispersion of the short wavelength band. The straight line indicating the relationship is based on the orthogonal coordinate of the partial dispersion ratio (θg, F) on the vertical axis and the Abbe number (ν _d ) on the horizontal axis, and the partial dispersion ratio of NSL7 and PBM2 and Abbe are drawn. The line connecting the two points is called the normal line (see Figure 1). The regular glass that becomes the basis of the regular line varies according to each optical glass manufacturer, but each company is also defined by roughly equal slope and intercept. (NSL7 and PBM2 are optical glass 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. The dispersion ratio (θg, F) is 0.5436).

Here, as the glass having a higher refractive index (n _d ) of 1.73 or more and a higher Abbe number (lower dispersion) of 45 or more, for example, optical glasses as disclosed in Patent Documents 1 to 3 are known.

Further, as a glass having a higher refractive index (n _d ) of 1.70 or more and a higher Abbe number (lower dispersion) of 39 or more and less than 52, for example, it is known that a large amount of La _{2 is} contained as shown in Patent Documents 4 to 6. An optical glass of a rare earth element such as an O ₃ component.

Further, as the glass having a higher refractive index (n _d ) of 1.60 or more and 1.70 or less and a higher Abbe's number (ν _d ) of 50 or more, for example, optical glasses as disclosed in Patent Documents 7 to 10 are known.

Further, as a glass having a higher refractive index (n _d ) of 1.57 or more and a higher Abbe number (ν _d ) of 50 or more, for example, it is known that a large amount of La ₂ O ₃ component, such as those shown in Patent Documents 11 to 19, is contained. Optical glass of rare earth element components.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-261877

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-084059

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-242210

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2005-170782

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-016295

[Patent Document 6] International Publication No. 2004/054937

[Patent Document 7] Japanese Patent Laid-Open Publication No. SHO 56-096747

[Patent Document 8] Japanese Patent Laid-Open No. 62-087433

[Patent Document 9] Japanese Patent Laid-Open No. Hei 11-157868

[Patent Document 10] Japanese Patent Laid-Open Publication No. 2006-117504

[Patent Document 11] Japanese Patent Laid-Open Publication No. 2007-261877

[Patent Document 12] Japanese Patent Laid-Open Publication No. 2009-084059

[Patent Document 13] Japanese Patent Laid-Open Publication No. 2009-242210

[Patent Document 14] Japanese Patent Laid-Open Publication No. 2006-117503

[Patent Document 15] Japanese Patent Laid-Open No. Hei 11-139844

[Patent Document 16] Japanese Patent Laid-Open No. 62-100449

[Patent Document 17] Japanese Patent Laid-Open Publication No. 2005-170782

[Patent Document 18] Japanese Patent Laid-Open Publication No. 2006-016295

[Patent Document 19] International Publication No. 2004/054937

However, the optical glass systems of Patent Documents 1 to 19 have a small dispersion ratio, and thus are not suitable as lenses for correcting the above secondary spectrum. That is, the manufacturer requires an optical glass having a low dispersion (high Abbe number) and a large partial dispersion ratio (θg, F). More specifically, the manufacturer requires an optical glass having a higher refractive index (n _d ) and a higher Abbe number (ν _d ) and a larger partial dispersion ratio (θg, F).

In particular, the glass disclosed in Patent Documents 5 to 13 has a problem that devitrification is likely to occur when glass is produced. Since a devitrified glass is produced, it is difficult to fabricate optical components such as light that controls, in particular, the visible area.

The present invention has been developed in view of the above problems, and an object thereof is to obtain an optical glass having a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range and preferably used for correcting chromatic aberration. And a lens preform using the same.

The inventors of the present invention have conducted intensive experimental studies to solve the above problems, and as a result, it has been found that by using a B ₂ O ₃ component and a La ₂ O ₃ component in combination, a high refractive index and a low dispersion of glass are achieved, and a partial dispersion ratio of glass (θg, The F) system also has the desired relationship with the Abbe number (ν _d ), thereby completing the present invention. In particular, it has been found that by including the F component, even if a rare earth element component such as a La ₂ O ₃ component having a strong partial dispersion ratio is contained, the partial dispersion ratio (θg, F) of the glass is also related to the Abbe number. having the desired relationship between a (ν _d).

Further, and also found that by using F ₂ O ₃ component and the B component, the low dispersion of the glass, and the partial dispersion ratio also improved, to thereby obtain the desired relationship between the Abbe number (ν _d).

Further, it has been found that the Al ₂ O ₃ component and the F component are used in combination with the B ₂ O ₃ component and the La ₂ O ₃ component to achieve a high refractive index and a low dispersion of the glass, and the effect of reducing the partial dispersion ratio is strong. The rare earth element component such as the La ₂ O ₃ component has a partial dispersion ratio, whereby a desired relationship is obtained between the Abbe number and the Abbe number (ν _d ), and the liquidus temperature of the glass is increased.

In particular, the invention provides the following.

(1) An optical glass comprising a B ₂ O ₃ component having a refractive index (n _d ) of 1.70 or more and an Abbe number (ν _d ) of 39 or more, and a partial dispersion ratio (θg, F) is associated with Abbe satisfied between the number _{(ν d) (θg, F} ) ≧ (-0.00170 × ν d +0.63750) or (θg, F) ≧ (-2.0 × 10 -3 × ν d +0.6498) of the relationship.

(2) The optical glass of (1) further comprising a La ₂ O ₃ component, having a refractive index (n _d ) of 1.73 or more and an Abbe number (ν _d ) of 45 or more, and a partial dispersion ratio (θg, F) line satisfies the relationship (θg, F) ≧ (-0.00170 × ν d +0.63750) between the number (ν _d) Abbe.

(3) The optical glass of (1) further comprising a La ₂ O ₃ component and an F component, having an Abbe number (ν _d ) of 39 or less and less than 52, and a partial dispersion ratio (θg, F) is associated with The relationship between (θg, F) ≧ (-2.0 × 10 ^-3 × ν _d + 0.6498) is satisfied between the number of shells (ν _d ).

(4) The optical glass of (1) further comprising an F component having XY orthogonal coordinates with an Abbe number (ν _d ) as the x-axis and a refractive index (n _d ) as the y-axis, having A Abbe number and refractive index of the range surrounded by 4 points of (50, 1.70), B (60, 1.60), C (63, 1.60), D (63, 1.70).

(5) The optical glass according to any one of (2) to (4), wherein the content of the B ₂ O ₃ component is 5.0 to 50.0% by mass, relative to the total mass of the glass of the oxide conversion composition, La The content of the ₂ O ₃ component is 55.0% or less.

(6) The optical glass according to (5), which contains 5.0% or more of the La ₂ O ₃ component with respect to the total mass of the glass in terms of oxide conversion.

(7) The optical glass according to (5) or (6), which contains 10.0% or more of the La ₂ O ₃ component with respect to the total mass of the glass of the oxide-converted composition.

(8) The optical glass according to any one of (5) to (7), wherein the content of the La ₂ O ₃ component is 50.0% or less with respect to the total mass of the glass of the oxide-converted composition.

(9) The optical glass according to any one of (1) to (8), further comprising an Al ₂ O ₃ component in the oxide-converted composition.

(10) The optical glass according to any one of (1) to (9), wherein the content of the Al ₂ O ₃ component is 20.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(11) The optical glass according to (10), which contains 0.1% or more and 20.0% or less of an Al ₂ O ₃ component in mass% based on the total mass of the glass in terms of an oxide conversion composition.

(12) The optical glass according to any one of (1) to (11), wherein the content of the F component is 30.0% or less based on the mass% of the oxide reference mass.

(13) The optical glass according to (12), wherein the external component is added in an amount of more than 0% by mass based on the mass % of the oxide reference mass.

(14) The optical glass according to (12) or (13), wherein the addition ratio is 0.1% or more of the F component based on the mass % of the oxide reference mass.

(15) (1) to (14) according to any one of the optical glass in which in terms of oxide relative to the total mass of the glass composition, in mass%, the content of SiO ₂ component was 40.0% or less.

(16) The optical glass of (15), wherein the content of the SiO ₂ component is 25.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(17) The optical glass of (15) or (16), wherein the SiO ₂ component is contained in an amount of 25.0% or less by mass based on the total mass of the glass in terms of oxide conversion.

(18) The optical glass according to any one of (1) to (17), wherein the mass of the total mass of the glass relative to the oxide-converted composition and (SiO ₂ + B ₂ O ₃ ) are 40.0% or less.

(19) The optical glass according to any one of (1) to (18), wherein the Gd ₂ O ₃ component is 0 to 40.0% and/or Y ₂ in mass % with respect to the total mass of the glass in terms of oxide conversion composition. The O ₃ component is 0 to 20.0% and/or the Yb ₂ O ₃ component is 0 to 20.0% and/or the Lu ₂ O ₃ component is 0 to 20.0%.

(20) The optical glass according to (19), which further comprises, by mass%, Gd ₂ O ₃ component 0 to 40.0% and/or Y ₂ O ₃ component 0 to 20.0. % and/or Yb ₂ O ₃ components 0 to 20.0% and/or Lu ₂ O ₃ components 0 to 10.0% of each component.

(21) The optical glass according to (19) or (20), which further comprises, by mass%, Gd ₂ O ₃ component 0 to 30.0% and/or Y ₂ O ₃ , based on the total mass of the glass in terms of oxide conversion composition. 0 to 20.0%, and component / component or Yb ₂ O ₃ 0 to 20.0%, and / or Lu ₂ O ₃ 0 to 10.0% of component ingredients.

The optical glass according to any one of (1) to (21), wherein the content of Gd ₂ O ₃ is 29.5% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(A) The optical glass according to any one of (1) to (22), wherein the Ln ₂ O ₃ component of the total mass of the glass in terms of oxide (wherein Ln is selected from the group consisting of La, Gd, Y, The mass sum of one or more of the groups of Yb and Lu is 80.0% or less.

(24) (23) of an optical glass, wherein in terms of oxides with respect to the total mass of Ln ₂ O ₃ of the glass component (wherein, Ln is selected from the group consisting of lines consisting of La, Gd, Y, Yb, Lu of The mass sum of one or more kinds is 20.0% or more.

(25) The optical glass according to (23) or (24), wherein the Ln ₂ O ₃ component of the total mass of the glass in terms of oxide (wherein Ln is selected from the group consisting of La, Gd, Y, Yb, and Lu) The mass of one or more of the constituent groups is 20.0% or more and 80.0% or less.

The optical glass according to any one of (1) to (25), wherein the Ln ₂ O ₃ component of the total mass of the glass in terms of oxide (wherein Ln is selected from the group consisting of La, Gd, Y, The mass of one or more of the groups of Yb and Lu is more than 43.0% and 80.0% or less.

(27) The optical glass of (26), wherein the Ln is selected from the group consisting of La, Gd, Y, and Yb with respect to the Ln ₂ O ₃ component of the total mass of the glass in the composition of the oxide. The quality of the above) is 63.5% or less.

(28) The optical glass according to (26) or (27), wherein the Ln ₂ O ₃ component of the total mass of the glass in terms of oxide composition (wherein Ln is selected from the group consisting of La, Gd, Y, Yb) The quality of one or more of the groups is less than 53.0%.

The optical glass according to any one of (1) to (28), wherein the mass of the total mass of the glass relative to the oxide-converted composition and (Gd ₂ O ₃ + Yb ₂ O ₃ ) are 26.0% or less.

(30) The optical glass according to any one of (1) to (29), wherein the mass ratio in the oxide-converted composition is Ln ₂ O ₃ /(Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ + Ta ₂ O ₅ ) is 1.7 or more and 25.0 or less.

(31) The optical glass according to any one of (1) to (30), wherein the mass ratio of the oxide-converted composition is Ln ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) of 1.00 or more (wherein, the Ln system One or more of the groups consisting of La, Gd, Y, Yb, and Lu are selected.

(32) The optical glass according to any one of (1) to (31) which further comprises, by mass%, a Bi ₂ O ₃ component of 0 to 10.0% and/or Each component of the TiO ₂ component is 0 to 15.0% and/or the Nb ₂ O ₅ component is 0 to 20.0%.

(33) (1) to (32) of the optical glass according to any, further comprising in terms of oxides with respect to the total mass of the glass composition, in mass%, WO ₃ 0 to 15.0% the component, and / or K ₂ O component 0~10.0% of each component.

(34) The optical glass according to any one of (1) to (33), wherein the mass of the total mass of the glass relative to the oxide is (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) is 0.1% or more and 30.0% or less.

(35) The optical glass of (34), wherein the mass of the total mass of the glass relative to the oxide-converted composition and (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) is 1.0. %the above.

(36) The optical glass according to any one of (1) to (35), wherein the mass of the total mass of the glass relative to the oxide is (Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ ) It is 20.0% or less.

(37) The optical glass according to (36), wherein the mass of the total mass of the glass relative to the oxide-converted composition and (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ ) are 10.0% or less.

(38) The optical glass according to any one of (1) to (37), wherein the mass ratio in the oxide-converted composition is F/(F+Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ +K ₂ O) is 0.36 or more and 1.00 or less.

(39) (1) to (38) of the optical glass according to any, further comprising in terms of oxides with respect to the total mass of the glass composition, in mass%, ZrO ₂ 0 to 15.0% components, and / or Ta ₂ The O ₅ component is 0 to 25.0%.

(40) The optical glass of (39), which further comprises, by mass%, ZrO ₂ component 0 to 15.0% and/or Ta ₂ O ₅ component 0 to 15.0% by mass of the glass. Each component.

(41) The optical glass according to any one of (1) to (40), wherein the mass of the total mass of the glass relative to the oxide is (WO ₃ + La ₂ O ₃ + ZrO ₂ + Ta ₂ O ₅ ) It is 10.0% or more and 60.0% or less.

(42) The optical glass according to any one of (1) to (41), wherein the mass of the total mass of the glass relative to the oxide is (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ + Ta ₂ O ₅ ) is more than 0%.

The optical glass according to any one of (1) to (42), wherein the content of the Li ₂ O component is 15.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(44) The optical glass according to (43), wherein the content of the Li ₂ O component is 10.0% or less by mass% based on the total mass of the glass of the oxide-converted composition.

(45) The optical glass of (44), wherein the content of the Li ₂ O component is 5.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(46) The optical glass according to any one of (1) to (45), wherein the mass ratio in the oxide-converted composition (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) / (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) is 2.00 or less.

(70) The optical glass according to any one of (1) to (46), wherein the mass ratio of the oxide-converted composition (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) /(Ta ₂ O ₅ +ZrO ₂ +Li ₂ O) is 0.50 or more.

(48) The optical glass of (47), wherein the mass ratio of the oxide-converted composition (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) / (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) is 1.3 or more.

(49) The optical glass according to any one of (1) to (48) further comprising, by mass%, MgO component 0 to 20.0% and/or CaO component 0, relative to the total mass of the glass in terms of oxide conversion composition. ~40.0% and/or SrO component 0~40.0% and/or BaO component 0~55.0% of each component.

(50) The optical glass according to (49), which further comprises, in mass%, MgO component 0 to 10.0% and/or CaO component 0 to 25.0% and/or SrO component, relative to the total mass of the glass in terms of oxide conversion composition. 0 to 25.0% and/or BaO components 0 to 55.0% of each component.

(51) The optical glass of (49) or (50), wherein the total mass of the glass in terms of oxide conversion is 0% to 10.0% by mass% of the MgO component and/or 0% to 15.0% of the CaO component and/or The SrO component is 0 to 15.0% and/or the BaO component is 0 to 25.0%.

(50) The optical glass according to any one of (1) to (51), wherein the R component is selected from the group consisting of Mg, Ca, Sr, Ba, relative to the total composition of the glass. The mass sum of one or more of the groups is 55.0% or less.

(53) The optical glass of (52), wherein the R component is selected from the group consisting of Mg, Ca, Sr, and Ba, and the RO component (in the formula, R is selected from the group consisting of Mg, Ca, Sr, and Ba) The mass sum is 25.0% or less.

(54) The optical glass of (52) or (53), wherein the R component is selected from the group consisting of Mg, Ca, Sr, and Ba, relative to the total composition of the glass. The mass sum of the above) is 20.0% or less.

(55) (1) to (54) according to any one of the optical glass, wherein in% relative to the total mass of the glass composition in terms of oxide, the content of Na ₂ O content of 20.0% or less.

(56) The optical glass of (55), wherein the content of the Na ₂ O component is 10.0% or less based on the mass % of the total mass of the glass in terms of oxide composition.

The optical glass according to any one of (1) to (56), wherein the Rn ₂ O component is selected from the total mass of the glass in the composition of the oxide (wherein Rn is selected from the group consisting of Li, Na, and K). The mass sum of one or more of the groups is 25.0% or less.

(58) The optical glass of (57), wherein the Rn ₂ O component (wherein Rn is selected from the group consisting of Li, Na, and K) is a component of the total mass of the glass in terms of an oxide conversion composition. The mass sum is 15.0% or less.

The optical glass according to any one of (1) to (58), wherein the content of the ZnO component is 30.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(60) The optical glass of (59), wherein the content of the ZnO component is 25.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(61) The optical glass of (59) or (60), wherein the content of the ZnO component is 15.0% or less by mass% based on the total mass of the glass of the oxide conversion composition.

(62) The optical glass according to any one of (1) to (61) which further comprises, by mass%, GeO ₂ component 0 to 10.0% and/or P ₂ in terms of total mass of the glass in terms of oxide conversion composition. O ₅ component 0~10.0% and/or Ga ₂ O ₃ component 0~10.0% and/or TeO ₂ component 0~10.0% and/or SnO ₂ component 0~5.0% and/or Sb ₂ O ₃ component 0~1.0 % of each ingredient.

(63) The optical glass of (62), wherein the GeO ₂ component is 0 to 10.0% and/or the P ₂ O ₅ component is 0 to 10.0% and/or based on the total mass of the oxide-converted composition. The Ga ₂ O ₃ component is 0 to 10.0% and/or the TeO ₂ component is 0 to 10.0% and/or the SnO ₂ component is 0 to 1.0% and/or the Sb ₂ O ₃ component is 0 to 1.0%.

The optical glass according to any one of (1) to (63), which has a refractive index (n _d ) of 1.57 or more and an Abbe number (ν _d ) of 45 or more.

The optical glass of any one of (1) to (64), wherein the Abbe number (ν _d ) is between ν _d ≧ -100 × n _d + 220 and the refractive index (n _d ) relationship.

The optical glass of any one of (1) to (65), wherein the Abbe number (ν _d ) is between ν _d ≧ -125 × n _d + 265 and the refractive index (n _d ) relationship.

(67) A preformed body comprising the optical glass of any one of (1) to (66).

(68) An optical element produced by extrusion molding a preformed body as in (67).

(69) An optical element comprising the optical glass of any one of (1) to (66) as a base material.

(70) An optical machine comprising an optical element such as (68) or (69).

According to the present invention, an optical glass having a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range and preferably used for correcting chromatic aberration, a preform using the same, and optical can be obtained. element.

The optical glass of the present invention contains a B ₂ O ₃ component, and the partial dispersion ratio (θg, F) is such that it satisfies (θg, F) ≧ (-0.00170 × ν _d + 0.63750) with the Abbe number (ν _d ) or (θg, F) ≧ (-2.0 × 10 ^-3 × ν _d + 0.6498). The partial dispersion ratio (θg, F) satisfies a specific relationship with the Abbe number (ν _d ), whereby the chromatic aberration of the optical element formed of the optical glass is lowered. Therefore, it is possible to obtain an optical glass having a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range and can be preferably used for correcting chromatic aberration, a preform using the same, and an optical element.

In particular, the optical glass of the first embodiment (hereinafter referred to as the first optical glass) contains a B ₂ O ₃ component and a La ₂ O ₃ component, and has a refractive index (n _d ) of 1.73 or more and 45 or more. The number of shells (ν _d ), the partial dispersion ratio (θg, F) is a relationship between (θg, F) ≧ (-0.00170 × ν _d + 0.63750) satisfied with the Abbe number (ν _d ). In particular, in the first optical glass, the B ₂ O ₃ component and the La ₂ O ₃ component are contained, whereby the refractive index of the glass is increased and the dispersion is reduced. Further, the partial dispersion ratio (θg, F) satisfies a specific relationship with the Abbe number (ν _d ), whereby the chromatic aberration of the optical element formed of the optical glass is lowered. Therefore, an optical glass having a refractive index (n _d ) and an Abbe number (ν _d ) in a desired range and having less coloration and being preferably used for correcting chromatic aberration, a preform using the same, and Optical element.

Further, the optical glass of the second embodiment (hereinafter referred to as a second optical glass) contains a B ₂ O ₃ component, a La ₂ O ₃ component, and an F component, and has a refractive index (n _d ) of 1.70 or more and 39 or more. The Abbe number (ν _d ) of 52 is not found, and the partial dispersion ratio (θg, F) is between (A, D, _D ) and (Abs), (θg, F) ≧ (-2.0 × 10 ^-3 × ν _d + 0.6498) relationship. In particular, in the second optical glass, the B ₂ O ₃ component and the La ₂ O ₃ component are contained, whereby the refractive index of the glass is increased and the dispersion is reduced, and the transparency to visible light is also improved. In addition, the F-component is included, and the rare-earth element component such as the La ₂ O ₃ component having a large partial dispersion ratio is contained, and the partial dispersion ratio (θg, F) is improved, whereby the optical element formed of the optical glass is used. The chromatic aberration drops. Therefore, an optical glass in which the refractive index (n _d ) and the Abbe number (ν _d ) are in a desired range and which is less colored and can be preferably used for correcting chromatic aberration can be obtained.

Further, the optical glass of the third embodiment (hereinafter, referred to as a third optical glass) contains a B ₂ O ₃ component and an F component, and has an Abbe number (ν _d ) as an x-axis and a refractive index (n _d ). The xy orthogonal coordinate of the y-axis has an Abbe number of a range surrounded by four points of A (50, 1.70), B (60, 1.60), C (63, 1.60), D (63, 1.70), and The refractive index and partial dispersion ratio (θg, F) are such that the relationship between (θg, F) ≧ -0.00170 × ν _d + 0.6375 is satisfied with the Abbe number (ν _d ). In particular, in the third optical glass, the B ₂ O ₃ component and the F component are used in combination, whereby low dispersion of the glass is achieved, and the partial dispersion ratio is also improved, thereby obtaining between the Abbe number and the Abbe number (ν _d ). The relationship required. Therefore, it is possible to obtain an optical glass having a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range and can be preferably used for correcting chromatic aberration, a preform using the same, and an optical element.

In addition, the optical glass (hereinafter referred to as the fourth optical glass) of the fourth embodiment contains 5.0 to 55.0% of a B ₂ O ₃ component and 10.0 to 55.0% of a La ₂ O ₃ component, and further contains Al. ₂ O ₃ component and F component. In particular, in the fourth optical glass, the B ₂ O ₃ component and the La ₂ O ₃ component are contained within a specific content range, whereby the refractive index of the glass is increased and the dispersion is reduced, and the transparency to visible light is improved. In addition, the Al ₂ O ₃ component and the F component are used in combination with the B ₂ O ₃ component and the La ₂ O ₃ component, and even a rare earth element component such as a La ₂ O ₃ component having a strong partial dispersion ratio is contained. The dispersion ratio (θg, F) also increases, and the liquidus temperature of the glass increases. Therefore, it is possible to obtain an optical glass in which the refractive index (n _d ) and the Abbe number (ν _d ) are in a desired range and can be preferably used for correcting chromatic aberration and having high devitrification resistance.

Hereinafter, the embodiment 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 present invention. In addition, the description of the place where the description is repeated will be appropriately omitted, but the purpose of the invention is not limited.

[Glass composition]

Hereinafter, the composition range of each component constituting the optical glass of the present invention will be described. In the present specification, the content of each component is expressed by mass% of the total mass of the glass in terms of oxide composition, unless otherwise specified. Here, the term "oxide-converting composition" refers to a case where an oxide, a composite salt, a metal fluoride or the like which is used as a raw material of the glass constituent component of the present invention is decomposed and becomes an oxide at the time of melting. The total mass of the produced oxide was set to 100% by mass to mark the composition of each component contained in the glass.

<About essential ingredients, optional ingredients>

The B ₂ O ₃ component is a component that forms a network structure inside the glass to promote stable glass formation. In particular, when the content of the B ₂ O ₃ component is 5.0% or more, it is difficult to devitrify the glass, and stable glass can be easily obtained. On the other hand, when the content of the B ₂ O ₃ component is 55.0% or less, the desired refractive index and dispersibility can be easily obtained. Therefore, the lower limit of the content of the B ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 5.0%, more preferably 8.0%, most preferably 10.0%, and still more preferably 13.0%. The best is 15.0%. On the other hand, the upper limit of the content of the B ₂ O ₃ component is preferably 55.0%, more preferably 50.0%, still more preferably 45.0%, still more preferably 40.0%, still more preferably 35.0%. In particular, in the optical glass of the present invention, the upper limit of the content of the B ₂ O ₃ component may be 30.0%. The B ₂ O ₃ component can be contained in the glass, for example, using H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ ‧10H ₂ O, BPO ₄ or the like as a raw material.

The La ₂ O ₃ component increases the refractive index of the glass and reduces the dispersed component.

In particular, when the content of the La ₂ O ₃ component is 55.0% or less, the phase separation of the glass is suppressed, and when the glass is produced, the glass is less likely to devitrify. Therefore, the upper limit of the content of the La ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 55.0%, more preferably 54.0%, still more preferably 53.0%, still more preferably 52.0%. Further, it is preferably 50.0%, and most preferably 45.0%. Further, the lower limit of the content of the La ₂ O ₃ component is appropriately set within the range in which the glass having the desired optical characteristics can be obtained. However, by setting the content of the La ₂ O ₃ component to 5.0% or more, it is easily obtained. A glass that requires a higher refractive index and a higher Abbe number and a higher transmittance to visible light. Therefore, the lower limit of the content of the La ₂ O ₃ component is preferably 5.0%, more preferably 10.0%, still more preferably 12.0%, still more preferably 13.0%, still more preferably 15.0%. The lower limit of the content of the La ₂ O ₃ component may be 20.0%, or the lower limit may be 25.0%. The La ₂ O ₃ component can be contained in the glass, for example, using La ₂ O ₃ or La(NO ₃ ) ₃ ‧XH ₂ O (any integer of X system) as a raw material.

The F component is a component that increases the partial dispersion ratio of the glass and is a component that lowers the transfer point (Tg) of the glass. In particular, when the content of the F component is 30.0% or less, the stability of the glass can be improved to make it difficult to devitrify. Therefore, the upper limit of the content of the F component in terms of the ratio with respect to the oxide reference mass is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%, most preferably 15.0%. In particular, in the third optical glass, the content of the F component may be set to 10.0% or less. Further, the optical glass of the present invention can obtain an optical glass having a desired higher partial dispersion ratio even if it does not contain the F component, but by containing the F component, a higher partial dispersion ratio can be obtained and coloring is also obtained. Less optical glass. Therefore, the lower limit of the content of the F component in terms of the ratio with respect to the oxide reference mass is preferably more than 0, more preferably 0.1%, still more preferably more than 0.5%, and still more preferably 1.0%. Further preferably, it is more than 1.0%, further preferably more than 2.0%, further preferably 3.0%, and most preferably more than 3.0%. In particular, the lower limit of the content of the F component in the external ratio may be 5.0%, or the lower limit may be 6.2%, or the lower limit may be 6.8%. Further, in the fourth optical glass, the lower limit of the content of the F component may be preferably 6.0%, more preferably 7.0%, and most preferably 8.0%. The F component can be contained in the glass, for example, using ZrF ₄ , AlF ₃ , NaF, CaF ₂ , LaF ₃ or the like as a raw material.

Further, the content of the F component in the present specification is assumed to be such that all of the cationic components constituting the glass form an oxide which is bonded to the oxygen which is just a charge balance amount and the mass of the entire glass formed by the oxides is set to 100%, and the mass of the F component is expressed in mass% (relative to the oxide reference mass plus the proportional mass%).

The Al ₂ O ₃ component is a component which is easy to form a stable glass and is an optional component in the optical glass of the present invention. In particular, when the content of the Al ₂ O ₃ component is 20.0% or less, the decrease in the Abbe number of the glass can be suppressed. Therefore, the upper limit of the content of the Al ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%. The upper limit of the content of the Al ₂ O ₃ component may be preferably 8.0%, more preferably 5.0%, most preferably 2.0%. Here, the Al ₂ O ₃ component may not be included, but in particular, in the fourth optical glass, the decrease in the Abbe number of the glass can be suppressed by including the Al ₂ O ₃ component. Therefore, the lower limit of the content of the Al ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably more than 0%, more preferably 0.1%, still more preferably 0.5%, and still more preferably 1.0%, further preferably more than 3.0%, most preferably more than 3.4%. The Al ₂ O ₃ component can be contained in the glass, for example, using Al ₂ O ₃ , Al(OH) ₃ , AlF ₃ or the like as a raw material.

In particular, in the fourth optical glass, the ratio of the content of the Al ₂ O ₃ component to the content of the F component is preferably more than 0 and not more than 15.0. By setting the ratio within a specific range, the stability of the glass is improved, and thus a glass having higher devitrification resistance can be obtained. Therefore, the composition in terms of oxides by mass than the lower limit of Al ₂ O ₃ / F is preferably greater than the set 0, more preferably 0.1, most preferably 0.3. On the other hand, the upper limit of the ratio is preferably 15.0, more preferably 10.0, still more preferably 5.0, still more preferably 4.0, most preferably 3.2. Further, in the ratio of the content, the content of the F component refers to the content in addition to the oxide reference mass, and the content of the Al ₂ O ₃ component means the total mass of the glass in terms of the oxide conversion composition. content.

The SiO ₂ component is a component which promotes stable glass formation and suppresses devitrification (production of crystallized matter) when glass is produced, and is an optional component in the optical glass of the present invention. In particular, when the content of the SiO ₂ component is 40.0% or less, the SiO ₂ component is easily dissolved in the molten glass, and dissolution at a high temperature can be avoided. The upper limit of the content of the SiO ₂ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 40.0%, more preferably 30.0%, still more preferably less than 28.0%, still more preferably 25.0%, and further It is preferably less than 25.0%, more preferably 24.0%, still more preferably 20.0%, and most preferably less than 20.0%. In particular, in the first, second, and fourth optical glasses, the upper limit of the content of the SiO ₂ component may be 15.0%, or the upper limit may be 10.0%. Further, even if the SiO ₂ component is not contained, a glass having a desired higher partial dispersion ratio can be obtained, but by containing the SiO ₂ component, the devitrification resistance of the glass can be improved. Therefore, the lower limit of the content of the SiO ₂ component relative to the total mass of the glass in the oxide conversion composition is preferably more than 0%, preferably 0.1%, more preferably 0.5%, still more preferably 1.0%. In particular, in the third optical glass, the lower limit of the content of the SiO ₂ component may be 4.0% or more than 5.0%. The SiO ₂ component can be contained in the glass, for example, using SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

In particular, in the fourth optical glass, the mass ₂ O ₃ component and the B component and SiO ₂ is preferably 40.0% or less. Thereby, the decrease in the refractive index of the glass is suppressed, so that an optical glass having a desired high refractive index can be obtained. Therefore, the mass of the total mass of the glass and the upper limit of (SiO ₂ + B ₂ O ₃ ) with respect to the oxide-converted composition are preferably 40.0%, more preferably 35.0%, and most preferably 32.0%. Further, from the viewpoint of obtaining a glass having high stability and high devitrification resistance, the lower limit of the mass and (SiO ₂ + B ₂ O ₃ ) is preferably 5.0%, more preferably 10.0. %, the best is 15.0%.

The Gd ₂ O ₃ component increases the refractive index of the glass and reduces the dispersed component.

In particular, when the content of the Gd ₂ O ₃ component is 40.0% or less, the phase separation of the glass is suppressed, and when the glass is produced, the glass is less likely to devitrify.

Therefore, the upper limit of the content of the Gd ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 40.0%, more preferably 35.0%, still more preferably 30.0%, and most preferably 29.5%.

In particular, in the third optical glass, the content of the Gd ₂ O ₃ component may preferably be less than 28.0%, more preferably less than 25.0%, and most preferably less than 20.0%.

Further, even if the Gd ₂ O ₃ component is not contained, a glass having a desired higher partial dispersion ratio can be obtained, but by containing 0.1% or more of the Gd ₂ O ₃ component, the desired refractive index can be easily obtained. Dispersibility. Thus, with respect to the lower limit of the content of component ₂ O ₃ in terms of oxides to the total mass of the glass composition is preferably Gd 0.1%, more preferably 1.0%, and further preferably 2.0%. In particular, in the first and fourth optical glasses, the lower limit of the content of the Gd ₂ O ₃ component may be 5.0%, or the lower limit may be 7.0%. The Gd ₂ O ₃ component can be contained in the glass, for example, using Gd ₂ O ₃ or GdF ₃ as a raw material.

The Y ₂ O ₃ component, the Yb ₂ O ₃ component, and the Lu ₂ O ₃ component increase the refractive index of the glass and reduce the dispersed component. Here, the content of the Y ₂ O ₃ component, the Yb ₂ O ₃ component, or the Lu ₂ O ₃ component is 20.0% or less, whereby the glass is hardly devitrified. In particular, when the content of the Yb ₂ O ₃ component is 10.0% or less, absorption on the long wavelength side of the glass (near the wavelength of 1000 nm) is less likely to occur, so that the resistance of the glass to infrared rays can be improved. Therefore, the upper limit of the content of the Y ₂ O ₃ component and the Yb ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%. Further, it is preferably 8.0%, more preferably 5.0%, and most preferably 4.0%. Further, the upper limit of the content of the Lu ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%, still more preferably 8.0%. Further, it is preferably 5.0%, and most preferably 3.0%. In particular, from the viewpoint of improving the resistance of the glass to infrared rays, the content of the Yb ₂ O ₃ component relative to the total mass of the glass in terms of oxide composition is preferably less than 3.0%, and most preferably less than 1.0. %. The Y ₂ O ₃ component, the Yb ₂ O ₃ component, and the Lu ₂ O ₃ component can be contained in the glass, for example, using Y ₂ O ₃ , YF ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ or the like as a raw material.

In the optical glass of the present invention, the mass of the Ln ₂ O ₃ component (wherein Ln is selected from one or more of the group consisting of La, Gd, Y, Yb, and Lu) is preferably 80.0% or less. . Thereby, the devitrification of the glass when the glass is produced can be reduced.

Therefore, the mass and the upper limit of the content of the Ln ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition are preferably 80.0%, more preferably 78.0%, and most preferably 75.0%. In particular, in the third optical glass, the mass and the upper limit of the content of the Ln ₂ O ₃ component may be preferably 63.5%, more preferably 60.0%, still more preferably 55.0%, and most preferably Less than 50.0%. Further, the lower limit of the total content of the Ln ₂ O ₃ component is appropriately selected within the range of the optical glass in which the desired characteristics can be obtained, but is, for example, more than 10.0%, whereby the desired higher refractive index can be easily obtained. And Abbe number, reduce coloration, and reduce the photoelastic constant. In particular, in the optical glass of the present invention, even if a large amount of rare earth is contained, the partial dispersion ratio is hard to be lowered, so that a desired higher partial dispersion ratio and a higher refractive index and Abbe number can be easily achieved. Therefore, the mass and the lower limit of the content of the Ln ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition are preferably more than 10.0%, more preferably more than 15.0%, and still more preferably more than 16.0%, further preferably 20.0%, most preferably more than 20.0%. In particular, in the first, second, and fourth optical glasses, the mass and the lower limit of the content of the Ln ₂ O ₃ component may be preferably 30.0%, more preferably 40.0%, and still more preferably More than 43.0%, further preferably 45.0%, further preferably 50.0%, most preferably 55.0%.

In particular, in the third optical glass, the sum of the Gd ₂ O ₃ component and the Yb ₂ O ₃ component is preferably 26.0% or less. Thereby, the Gd ₂ O ₃ component and the Yb ₂ O ₃ component which have a strong effect of increasing the refractive index are suppressed, so that the partial dispersion ratio is improved, and the desired refractive index and dispersion can be easily obtained. Therefore, the upper limit of the mass of the glass and the upper limit of (Gd ₂ O ₃ + Yb ₂ O ₃ ) with respect to the oxide-converted composition is preferably 26.0%, more preferably 23.0%, still more preferably 20.0%. The best is 15.0%.

Further, in the optical glass of the present invention, the content of Ln ₂ O ₃ is preferably 1.7 or more and 25.0 or less by mass and mass of (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ +Ta ₂ O ₅ ). . Thereby, the total content of the Abbe number Ln ₂ O _{3 is} increased with respect to the total content of the Bi ₂ O ₃ component, the TiO ₂ component, the WO ₃ component, the Nb ₂ O ₅ component, and the Ta ₂ O ₅ component which lowers the Abbe number. The content is within a specific range, so that the desired Abbe number can be easily obtained, and even the desired relationship between the partial dispersion ratio and the Abbe number can be obtained. Therefore, the lower limit of the mass ratio Ln ₂ O ₃ /(Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ +Ta ₂ O ₅ ) in the oxide-converted composition is preferably 1.7, more preferably 3.0, further preferably 5.0, and the upper limit thereof is preferably 25.0, more preferably 20.0, most preferably 16.8.

Further, in the fourth optical glass, the content of Ln ₂ O ₃ (wherein Ln is selected from one or more of the group consisting of La, Gd, Y, Yb, and Lu) is a component of SiO ₂ component and B ₂ O. The mass and ratio of the _three components are preferably 1.00 or more. When the ratio is 1.00 or more, the refractive index is further improved even if the Al ₂ O ₃ component is contained, so that an optical glass having a high partial dispersion ratio and having both glass stability and high refractive index can be obtained. . Therefore, the lower limit of the mass ratio Ln ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) of the oxide-converted composition is preferably 1.00, more preferably 1.25, and most preferably 1.40. On the other hand, the upper limit of the ratio is not particularly limited as long as a stable glass can be obtained. However, for example, when it exceeds 10.0, it is presumed that there is a possibility that devitrification is likely to occur. Therefore, the upper limit of the mass ratio of the oxide-converted composition of Ln ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is preferably 10.00, more preferably 8.00, and most preferably 5.00. Among the Ln ₂ O ₃ components, the La ₂ O ₃ component has an effect of further improving the stability of the glass, and therefore, it is more preferable to use La ₂ O ₃ / from the viewpoint of obtaining a glass having particularly high devitrification resistance. The ratio of (SiO ₂ + B ₂ O ₃ ) is set within the above range. Further, from the viewpoint of obtaining a glass having higher devitrification resistance, the upper limit of the mass ratio of the oxide-converted composition of La ₂ O ₃ /B ₂ O _{3 may} preferably be 10.00, more preferably 5.00. Further, it is preferably 3.50, more preferably 2.30, most preferably less than 2.00.

The Bi ₂ O ₃ component is a component which increases the refractive index of the glass and increases the refractive index of the glass and lowers the composition of the glass transition point, and is an optional component in the optical glass of the present invention. In particular, when the content of the Bi ₂ O ₃ component is 10.0% or less, it is possible to make it difficult to deteriorate the light transmittance of the visible short wavelength (below 500 nm). Therefore, the upper limit of the content of the Bi ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, most preferably 5.0%. The Bi ₂ O ₃ component can be contained in the glass, for example, using Bi ₂ O ₃ or the like as a raw material.

The TiO ₂ component is a component which increases the refractive index of the glass and which increases the refractive index and dispersion of the glass and improves the chemical durability of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the TiO ₂ component is 15.0% or less, it is easy to obtain a desired high Abbe number, and it is difficult to deteriorate the light transmittance of a visible short wavelength (500 nm or less). Therefore, the upper limit of the content of the TiO ₂ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 15.0%, more preferably 12.0%, still more preferably 10.0%, still more preferably 8.0%. It is preferably 7.0%, and most preferably 5.0%. The TiO ₂ component can be contained in the glass, for example, using TiO ₂ or the like as a raw material.

The Nb ₂ O ₅ component is a component which increases the refractive index of the glass and increases the refractive index and dispersion of the glass and improves the chemical durability of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Nb ₂ O ₅ component to 20.0% or less, the desired higher Abbe number can be easily obtained. Therefore, the upper limit of the content of the Nb ₂ O ₅ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Nb ₂ O ₅ component can be contained in the glass, for example, using Nb ₂ O ₅ or the like as a raw material.

The WO ₃ component is a component which increases the refractive index of the glass and increases the refractive index and dispersion of the glass and improves the chemical durability of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the WO ₃ component is 15.0% or less, it is easy to obtain a desired high Abbe number, and it is difficult to deteriorate the light transmittance of a visible short wavelength (500 nm or less). Therefore, the upper limit of the content of the WO ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 15.0%, more preferably 12.0%, still more preferably 10.0%, still more preferably 8.0%, most Good is 5.0%. Further, even if the WO ₃ component is not contained, an optical glass having a desired higher partial dispersion ratio can be obtained. However, by setting the content of the WO ₃ component to 0.1% or more, the partial dispersion ratio of the glass can be increased. A glass having a desired higher partial dispersion ratio can be easily obtained. Therefore, the lower limit of the content of the WO ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 0.1%, more preferably 0.3%, most preferably 0.5%. The WO ₃ component can be contained in the glass, for example, using WO ₃ or the like as a raw material.

The K ₂ O component is a component which further increases the component of the glass partial dispersion ratio and improves the meltability of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the K ₂ O component is 10.0% or less, the refractive index of the glass is hardly lowered, and the stability of the glass is improved to prevent devitrification or the like from occurring. Therefore, the upper limit of the content of the K ₂ O component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. The K ₂ O component can be contained in the glass, for example, using K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material.

The optical glass of the present invention is preferably one or more selected from the group consisting of an F component, a Bi ₂ O ₃ component, a TiO ₂ component, a WO ₃ component, a Nb ₂ O ₅ component, and a K ₂ O component. It is 0.1% or more. When the sum is made 0.1% or more, it is necessary to include a component which increases the partial dispersion ratio, so that a desired higher partial dispersion ratio can be easily obtained. Further, since the partial dispersion ratio of the glass is increased, the partial dispersion ratio can have a desired relationship with the Abbe number. Therefore, the content and the lower limit of the components relative to the mass of the oxide-converted composition are preferably 0.1%, more preferably 1.0%, still more preferably 3.0%, still more preferably 4.0%, and further Preferably, it is 5.0%, more preferably 6.2%, and most preferably 8.0%. On the other hand, the content and the upper limit of the components are not particularly limited as long as a stable glass can be obtained. However, for example, when it exceeds 60.0%, it is presumed that there is a possibility that devitrification is likely to occur. Therefore, the content and the upper limit of the components relative to the mass of the oxide-converted composition are preferably 60.0%, more preferably 50.0%, still more preferably 40.0%. In particular, in the second and third optical glasses, the content and the upper limit of the components relative to the mass of the oxide-converted composition may be preferably 30.0%, more preferably 25.0%, more preferably 20.0%, the best is 15.0%. Further, in the content and content, the content of the F component means a content in addition to the oxide-based mass, and a Bi ₂ O ₃ component, a TiO ₂ component, a WO ₃ component, a Nb ₂ O ₅ component, and K. The content of the ₂ O component means the content of the total mass of the glass relative to the oxide conversion composition.

Among these components, the K ₂ O component has a function of lowering the refractive index, and therefore, from the viewpoint of obtaining a glass having a particularly high refractive index, it is preferable to contain a component selected from the group consisting of F component, Bi ₂ O ₃ component, and TiO _{2 .} One or more of the group consisting of a component, a WO ₃ component, and a Nb ₂ O ₅ component. Further, since the Nb ₂ O ₅ component has a strong effect of lowering the Abbe number, it is preferable to include a component selected from the F component, the Bi ₂ O ₃ component, and the TiO from the viewpoint of obtaining a glass having a particularly high Abbe number. One or more of the group consisting of the _two components, the WO ₃ component, and the K ₂ O component. Further, since the Bi ₂ O ₃ component, the TiO ₂ component, and the WO ₃ component have a strong effect of coloring the glass, it is preferable to include a component selected from the F component and the Nb from the viewpoint of obtaining a glass having a particularly small coloration. One or more of the group consisting of ₂ O ₅ component and K ₂ O component. Therefore, from the viewpoint of obtaining a glass having a higher partial dispersion ratio and a higher refractive index and Abbe number and less coloration, it is preferred to increase the content of the components particularly in the F component.

In the optical glass of the present invention, the content of the Bi ₂ O ₃ component, the TiO ₂ component, the WO ₃ component and the Nb ₂ O ₅ component in the components is preferably 20.0% or less. Thereby, the component which is improved in dispersion is reduced, so that the glass having the desired dispersion can be easily obtained. Further, since the decrease in the stability of the glass caused by the excessive inclusion of the components is suppressed, the devitrification resistance of the glass can be further improved. Therefore, the upper limit of the mass of the glass and the upper limit of (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ ) with respect to the oxide-converted composition is preferably 20.0%, more preferably 15.0%, most Good is 10.0%. In particular, the mass and the upper limit in the third optical glass may be set to 8.0%, and the upper limit may be set to 5.0%. Further, from the viewpoint of obtaining a glass which is particularly small in dispersion, the mass sum may be set to less than 0.5%. On the other hand, even if it does not contain any of these components, an optical glass having a desired higher partial dispersion ratio can be obtained, but by partially setting the mass of the components to 0.1% or more, partial dispersion of the glass can be improved. In contrast, it is easy to obtain a glass having a desired higher partial dispersion ratio. Therefore, the lower limit of the mass and (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ ) may be preferably 0.1%, more preferably from the viewpoint of obtaining a higher partial dispersion ratio. It is 0.5%, and further preferably 0.8%.

In particular, in the third optical glass, the content of the component F and the ratio of the content of the F component, the Bi ₂ O ₃ component, the TiO ₂ component, the WO ₃ component, the Nb ₂ O ₅ component, and the K ₂ O component are preferably 0.36 or more. In particular, the ratio is set to 0.36 or more, whereby a large amount of a component which increases the partial dispersion ratio and which is less colored is obtained, so that a transparent glass having a desired partial dispersion ratio can be obtained. Therefore, the lower limit of the mass ratio F/(F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) in the oxide-converted composition is preferably 0.36, more preferably 0.40. Further preferably, it is 0.50. Further, the mass ratio is preferably 1.00, but it may be less than 1.00 from the viewpoint of obtaining a more stable glass.

The ZrO ₂ component is a component which increases the refractive index of the glass and improves the resistance to devitrification when the glass is produced, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the ZrO ₂ component to 15.0% or less, it is possible to suppress a decrease in the partial dispersion ratio of the glass. Further, by setting the content of the ZrO ₂ component to 15.0% or less, the decrease in the Abbe number of the glass is suppressed, and the melting at a high temperature during the production of the glass is avoided, and the energy loss at the time of glass production can be reduced. Therefore, the upper limit of the content of the ZrO ₂ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 15.0%, more preferably 10.0%, still more preferably 8.0%, still more preferably 7.0%. It is preferably 5.0%, and most preferably it is less than 4.0%. Further, even if the ZrO ₂ component is not contained, a glass having desired optical characteristics can be obtained. However, by setting the content of the ZrO ₂ component to 0.1% or more, the devitrification resistance of the glass can be improved. Therefore, in the case of containing the ZrO ₂ component, the lower limit of the content of the ZrO ₂ component relative to the total mass of the glass of the oxide conversion composition is preferably 0.1%, more preferably 0.5%, still more preferably 1.0%. . The ZrO ₂ component can be contained in the glass, for example, using ZrO ₂ or ZrF ₄ as a raw material.

The Ta ₂ O ₅ component is a component which increases the refractive index of the glass and stabilizes the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the Ta ₂ O ₅ component is 25.0% or less, the decrease in the partial dispersion ratio of the glass can be suppressed. Further, by setting the content of the Ta ₂ O ₅ component to 25.0% or less, the material cost of the glass can be lowered, and the melting at high temperature can be avoided to reduce the energy loss at the time of glass production. Therefore, the upper limit of the content of the Ta ₂ O ₅ component relative to the total mass of the glass in the oxide conversion composition is preferably 25.0%, more preferably less than 16.5%, still more preferably 15.0%, and still more preferably 10.0%, the best is 5.0%. The Ta ₂ O ₅ component can be contained in the glass, for example, using Ta ₂ O ₅ or the like as a raw material.

The optical glass of the present invention, WO ₃ components, La ₂ O ₃ component, ZrO ₂ component, and Ta ₂ O ₅ content of 10.0% and preferably less than. The sum is made 10.0% or more, whereby the color of the glass is lowered, and the refractive index can be further increased. Therefore, the content and the lower limit of the components relative to the mass of the oxide-converted composition are preferably 10.0%, more preferably 20.0%, still more preferably 25.0%, most preferably 30.0%. On the other hand, the content and the upper limit of the components are not particularly limited as long as a stable glass can be obtained. However, for example, when it exceeds 65.0%, it is presumed that there is a possibility that devitrification is likely to occur. Therefore, the content and the upper limit of the components relative to the mass of the oxide-converted composition are preferably 65.0%, more preferably 60.0%, still more preferably 55.0%, most preferably 50.0%.

In particular, the second optical glass is preferably one or more selected from the group consisting of a Bi ₂ O ₃ component, a TiO ₂ component, a WO ₃ component, a Nb ₂ O ₅ component, and a Ta ₂ O ₅ component. More than 0%. Thereby, the Abbe number of the glass is reduced, so that an optical glass having an Abbe number of a desired range can be easily obtained. Therefore, the content and the lower limit of the components relative to the mass of the oxide-converted composition are preferably more than 0%, more preferably 1.0%, most preferably 2.0%. On the other hand, the content and the upper limit of the components are not particularly limited as long as a stable glass can be obtained. However, for example, when it exceeds 25.0%, it is presumed that there is a possibility that devitrification is likely to occur. Therefore, the content and the upper limit of the components relative to the mass of the oxide-converted composition are preferably 25.0%, more preferably 15.0%, and most preferably 10.0%.

The Li ₂ O component is a component which improves the meltability of the glass and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Li ₂ O component to 15.0% or less, the partial dispersion ratio of the glass is suppressed from decreasing, whereby the partial dispersion ratio and the Abbe number can be maintained in a desired relationship. In addition, the content of the Li ₂ O component is set to 15.0% or less, whereby the decrease in the refractive index of the glass is suppressed, and devitrification caused by the inclusion of an excessive amount of the Li ₂ O component is hard to occur. Therefore, the upper limit of the content of the Li ₂ O component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 15.0%, more preferably 10.0%, still more preferably 8.0%, still more preferably 5.0%. It is more preferably 4.0%, further preferably 3.0%, further preferably less than 3.0%, and further preferably 2.3%. In particular, from the viewpoint of easily obtaining an optical glass having a higher partial dispersion ratio, the content of the Li ₂ O component may be 0.5% or less, or may be 0.4% or less, or may be set to Less than 0.1%, or not included. The Li ₂ O component can be contained in the glass, for example, using Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

In the optical glass of the present invention, the content of the Ta ₂ O ₅ component, the ZrO ₂ component, and the Li ₂ O component, and the F component, the Bi ₂ O ₃ component, the TiO ₂ component, the WO ₃ component, the Nb ₂ O ₅ component, and the K The content of the ₂ O component and the ratio thereof are preferably 2.00 or less. Thereby, since the content of the component having the effect of lowering the partial dispersion ratio is less than the component having the effect of increasing the partial dispersion ratio, a glass having a higher partial dispersion ratio can be obtained. Therefore, the upper limit of the mass ratio (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) / (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) in the oxide-converted composition The ratio is preferably 2.00, more preferably 1.40, still more preferably 1.00, most preferably 0.80. Further, the mass ratio may be 0. However, by setting the mass ratio to 0.10 or more, the devitrification resistance of the glass can be further improved. Therefore, the lower limit of the mass ratio (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) / (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) in the composition of the oxide It is preferably set to 0.10, more preferably 0.20, and most preferably 0.30.

Further, in the optical glass of the present invention _{in, (F + Bi 2 O 3} + TiO 2 + WO 3 + Nb 2 O 5 + K 2 O) of the mass and the _{(Ta 2 O 5 + ZrO 2} + Li 2 O) of The mass and the ratio are preferably 0.50 or more. Thereby, since the content of the component having a partial dispersion ratio is increased more than the content of the component having a large partial dispersion ratio, even if more rare earth is added, a desired higher partial dispersion ratio can be easily obtained. That is, it is easy to achieve both a higher partial dispersion ratio and a higher Abbe number. Therefore, the lower limit of the mass ratio (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) / (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) in the composition of the oxide The ratio is preferably 0.50, more preferably 1.00, still more preferably 1.32, still more preferably 1.70. In particular, in the first optical glass, the lower limit of the ratio of the content may be preferably 1.3, more preferably 1.5, and most preferably 2.0. On the other hand, the upper limit of the ratio of the content is not particularly limited, and may be infinite (i.e., Ta ₂ O ₅ + ZrO ₂ + Li ₂ O = 0%), but the viewpoint of further improving the stability of the glass is obtained. In terms of, the ratio may be 100.0 or less.

The MgO component, the CaO component, the SrO component, and the BaO component are components which improve the meltability of the glass and improve the devitrification resistance, and are optional components in the optical glass of the present invention. In particular, when the content of the MgO component is 20.0% or less, the content of the CaO component or the SrO component is 40.0% or less, or the content of the BaO component is 55.0% or less, whereby the refractive index of the glass can be made difficult. decline. Therefore, the upper limit of the content of the MgO component relative to the total mass of the glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%, still more preferably 8.0%, and most preferably It is 5.0%. Further, the upper limit of the content of the CaO component based on the total mass of the glass in terms of the oxide conversion composition is preferably 40.0%, more preferably 30.0%, still more preferably 25.0%, still more preferably 20.0%, and further It is preferably 15.0%, more preferably 12.0%, still more preferably 10.0%, and most preferably less than 10.0%. Further, the upper limit of the content of the SrO component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 40.0%, more preferably 30.0%, still more preferably 25.0%, still more preferably 20.0%, and further The ratio is less than 16.0%, and more preferably 15.0%. Further, the upper limit of the content of the SrO component may be more preferably 12.0%, still more preferably 10.0%. Further, the upper limit of the content of the BaO component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 55.0%, more preferably 45.0%, still more preferably 40.0%, still more preferably 35.0%, and further Jiawei did not reach 30.0%. Further, the upper limit of the content of the BaO component may be preferably 25.0%, more preferably 20.0%, still more preferably 15.0%. In particular, in the second optical glass, the upper limit of the content of the BaO component may be 10.0% or may be less than 6.0%. For the MgO component, the CaO component, the SrO component, and the BaO component, for example, MgCO ₃ , MgF ₂ , CaCO ₃ , CaF ₂ , Sr(NO ₃ ) ₂ , SrF ₂ , BaCO ₃ , Ba(NO ₃ ) ₂ or the like can be used as a raw material. Contained in glass.

In the optical glass of the present invention, the mass of the RO component (wherein R is selected from one or more of the group consisting of Mg, Ca, Sr, and Ba) is preferably 55.0% or less. Thereby, the devitrification of the glass caused by the excessive RO component is lowered, and the refractive index of the glass is hard to be lowered. Therefore, the mass and the upper limit of the content of the RO component relative to the total mass of the glass in terms of the oxide conversion composition are preferably 55.0%, more preferably 45.0%, still more preferably 40.0%, and most preferably 35.0%. Further, the mass and the upper limit of the content of the RO component may be preferably 25.0%, more preferably 20.0%, still more preferably 15.0%, most preferably 10.0%.

The Na ₂ O component is a component which improves the meltability of the glass and is an optional component in the optical glass of the present invention. In particular, when the content of the Na ₂ O component is 20.0% or less, the refractive index of the glass is hardly lowered, and the stability of the glass is improved to make it difficult to cause devitrification or the like. Therefore, the upper limit of the content of the Na ₂ O component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%, still more preferably 8.0%, most Good is 5.0%. The Na ₂ O component can be contained in the glass, for example, using Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like as a raw material.

The Rn ₂ O component (wherein Rn is selected from one or more of the group consisting of Li, Na, and K) is a component which improves the meltability of the glass and lowers the glass transition point to lower the devitrification of the glass. Here, when the content of the Rn ₂ O component is 25.0% or less, the refractive index of the glass is hardly lowered, and the stability of the glass is improved to reduce the occurrence of devitrification or the like. Therefore, the mass and the upper limit of the Rn ₂ O component relative to the total mass of the glass in terms of the oxide conversion composition are preferably 25.0%, more preferably 20.0%, and most preferably 15.0%. In particular, in the fourth optical glass, the upper limit of the mass and the mass may be set to 10.0%, or the upper limit may be set to 5.0%.

The ZnO component is an optional component in the optical glass of the present invention which is a component which improves the meltability of glass, lowers the glass transition point, and easily forms a stable glass.

In particular, the photoelastic constant of the optical glass is slightly suppressed by setting the content of the ZnO component to 30.0% or less. Therefore, the polarizing characteristics of the transmitted light of the optical glass can be improved, and the color rendering property in the projector or the camera can be improved.

Therefore, the upper limit of the content of the ZnO component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%, still more preferably 15.0%, and further It is preferably 12.0%, more preferably 10.0%, still more preferably 8.7%, still more preferably 7.7%. In particular, in the first optical glass, the upper limit of the content of the ZnO component may be set to 5.0%. The ZnO component can be contained in the glass, for example, using ZnO, ZnF ₂ or the like as a raw material.

The GeO ₂ component is a component having an effect of increasing the refractive index of glass and improving the resistance to devitrification, and is an optional component in the optical glass of the present invention. However, since the raw material of the GeO ₂ component is expensive, if the amount is large, the material cost increases, and thus the obtained glass is not practical. Therefore, the upper limit of the content of the GeO ₂ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%, still more preferably 2.0%, most Jiawei did not reach 2.0%. The GeO ₂ component can be contained in the glass, for example, using GeO ₂ or the like as a raw material.

The P ₂ O ₅ component is a component having an effect of lowering the liquidus temperature of the glass and improving the resistance to devitrification, and is an optional component in the optical glass of the present invention. In particular, when the content of the P ₂ O ₅ component is 10.0% or less, the chemical durability of the glass, particularly the water resistance, can be suppressed. Therefore, the upper limit of the content of the P ₂ O ₅ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%, most preferably 2.0%. The P ₂ O ₅ component can be contained in the glass, for example, using Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ or the like as a raw material.

The Ga ₂ O ₃ component is a component which is easy to form a stable glass and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Ga ₂ O ₃ component to 10.0% or less, the decrease in the Abbe number of the glass can be suppressed. Therefore, the upper limit of the content of the Ga ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%, and most preferably 2.0%. . The Ga ₂ O ₃ component can be contained in the glass, for example, using Ga ₂ O ₃ or Ga(OH) ₃ as a raw material.

The TeO ₂ component is a component which increases the refractive index and lowers the glass transition point (Tg) and is an optional component in the optical glass of the present invention. However, TeO ₂ has a problem in that it may be alloyed with platinum when molten glass raw material is melted in a molten bath of platinum or a portion where platinum is formed in contact with molten glass. Therefore, the upper limit of the content of the TeO ₂ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. The TeO ₂ component can be contained in the glass, for example, using TeO ₂ or the like as a raw material.

The SnO ₂ component is a component which lowers the oxidation of the molten glass to purify the molten glass and hardly deteriorates the transmittance of the glass to light, and is an optional component in the optical glass of the present invention. In particular, when the content of the SnO ₂ component is 5.0% or less, it is possible to cause coloring of the glass or devitrification of the glass due to reduction of the molten glass. Further, since the alloying of the SnO ₂ component and the dissolving equipment (especially a noble metal such as Pt) is lowered, the life of the dissolving equipment can be extended. Therefore, the upper limit of the content of the SnO ₂ component relative to the total mass of the glass in the oxide conversion composition is preferably 5.0%, more preferably 3.0%, still more preferably 1.0%, still more preferably 0.7%, and most preferably It is 0.5%. The SnO ₂ component can be contained in the glass, for example, using SnO, SnO ₂ , SnF ₂ , SnF ₄ or the like as a raw material.

The Sb ₂ O ₃ component is a component which defoams molten glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the Sb ₂ O ₃ component is 1.0% or less, excessive foaming during melting of the glass is less likely to occur, and the Sb ₂ O ₃ component can be made difficult to dissolve with a dissolving device (especially a noble metal such as Pt). Alloying. Therefore, the upper limit of the content of the Sb ₂ O ₃ component relative to the total mass of the glass in terms of the oxide conversion composition is preferably 1.0%, more preferably 0.8%, most preferably 0.5%. The Sb ₂ O ₃ component can be contained in the glass, for example, using Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ ‧5H ₂ O or the like as a raw material.

Further, the component for purifying and defoaming the glass is not limited to the above Sb ₂ O ₃ component, and a well-known scavenger, a defoaming agent or a combination thereof in the field of glass production can be used.

<About ingredients that should not be included>

Next, the components which should not be included in the optical glass of the present invention and the components which are not preferable in the description will be described.

In the optical glass of the present invention, other components may be added as needed within the range which does not impair the characteristics of the glass of the invention of the present application. Among them, since the GeO ₂ component causes an increase in dispersibility of the glass, it is preferably not substantially contained.

Further, in addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, each transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo is separate from each other. When it is combined or contained in a small amount, it also has a property that the glass is colored and absorbs at a specific wavelength of the visible region. Therefore, in particular, the optical glass using the wavelength of the visible region is preferably substantially not included.

Further, arsenic compounds such as PbO and arsenic compounds such as As ₂ O ₃ and various components of Th, Cd, Tl, Os, Be, and Se have been used for controlling harmful chemicals in recent years, and are not only manufacturing steps of glass, but also Environmental measures are required for the processing steps and after the product is finished. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that the inclusion is not included in addition to the inevitable mixing. Thereby, the optical glass does not substantially contain a substance that pollutes the environment. Therefore, the optical glass can be manufactured, processed, and discarded without implementing special environmental measures.

The glass composition of the present invention is represented by the mass % of the total mass of the glass in terms of oxide composition, and thus is not directly represented by the description of the mole %, but according to the characteristics satisfying the requirements of the present invention. The composition represented by mol% of each component present in the glass composition is approximately the following value in terms of oxide conversion composition. B ₂ O ₃ component 10.0~75.0 mol% and La ₂ O ₃ component 0~25.0 mol% and/or Bi ₂ O ₃ component 0-4.0 mol% and/or TiO ₂ component 0~30.0 mol% and/or WO ₃ components 0~10.0 mol% and/or Nb ₂ O ₅ component 0~10.0 mol% and/or K ₂ O component 0~15.0 mol% and/or Ta ₂ O ₅ component 0~10.0 mol% and/or ZrO ₂ Component 0~25.0 mol% and/or Li ₂ O component 0~40.0 mol% and/or Gd ₂ O ₃ component 0~20.0 mol% and/or Y ₂ O ₃ component 0~15.0 mol% and/or Yb ₂ O ₃ components 0~10.0 mol% and/or Lu ₂ O ₃ component 0~10.0 mol% and/or MgO component 0~50.0 mol% and/or CaO component 0~50.0 mol% and/or SrO component 0~50.0 mol% And/or BaO component 0~55.0 mol% and/or SiO ₂ component 0~70.0 mol% and/or ZnO component 0~30.0 mol% and/or GeO ₂ component 0~20.0 mol% and/or P ₂ O ₅ component 0~10.0 mol% and/or Al ₂ O ₃ component 0~40.0 mol% and/or Ga ₂ O ₃ component 0~8.0 mol% and/or Na ₂ O component 0~25.0 mol% and/or TeO ₂ component 0 ~8.0 mol% and/or SnO ₂ component 0-5.0 mol% and/or SnO ₂ component 0-1.0 mol% and/or Sb ₂ O ₃ component 0-0.5 mol% and one or two of the above metal elements Fluoride which is partially or completely substituted by one of the above oxides is taken as the total amount of F 0~75.0 mol%

In particular, the composition represented by the first optical glass molar % is preferably 5.0 to 25.0 mol% of the La ₂ O ₃ component and 0 to 5.0 mol% of the Ta ₂ O ₅ component and/or Li in terms of oxide conversion composition. ₂ O component 0~25.0 mol% and/or MgO component 0~35.0 mol% and/or CaO component 0~35.0 mol% and/or SrO component 0~25.0 mol% and/or BaO component 0~25.0 mol% and/or Or SiO ₂ component 0~60.0 mol% and/or Al ₂ O ₃ component 0~20.0 mol% and/or SnO ₂ component 0~1.0 mol%.

Further, the composition represented by the second optical glass mol% is preferably 5.0 to 25.0 mol% of the La ₂ O ₃ component and 0 to 30.0 mol% of the Li ₂ O component and/or Lu ₂ O in terms of oxide conversion composition. ₃ components 0~5.0 mol% and/or MgO component 0~35.0 mol% and/or CaO component 0~35.0 mol% and/or SrO component 0~25.0 mol% and/or BaO component 0~25.0 mol% and/or The SiO ₂ component is 0 to 60.0 mol% and/or the Al ₂ O ₃ component is 0 to 20.0 mol% and/or the SnO ₂ component is 0 to 1.0 mol%.

In particular, the composition represented by the third optical glass molar % is preferably 0 to 15.0 mol% of the Gd ₂ O ₃ component and/or 0 to 3.0 mol% of the Ta ₂ O ₅ component and/or in terms of oxide conversion composition. Or a fluoride of 0 to 25.0 mol% of the ZnO component and/or 0 to 20.0 mol% of the Al ₂ O ₃ component and a part or all of the oxide of one or more of the above metal elements. The total amount exceeds 0 mol% to 75.0 mol%.

Further, the composition represented by the fourth optical glass molar % is preferably from 10.0 to 75.0 mol% of the B ₂ O ₃ component, from 10.0 to 25.0 mol% of the La ₂ O ₃ component, and Al ₂ O _{3 in} terms of oxide conversion composition. The composition is more than 0 mol% to 40.0 mol% and the Ta ₂ O ₅ component is 0 to 4.0 mol% and/or the Li ₂ O component is 0 to 15.0 mol% and/or the MgO component is 0 to 35.0 mol% and/or the CaO component is 0 to 50.0. Mool% and/or SrO component 0~35.0 mol% and/or BaO component 0~50.0 mol% and/or ZnO component 0~25.0 mol% and one or more oxides of one or more of the above metal elements The total amount of fluoride which is substituted or completely substituted is more than 0 mol% to 75.0 mol%.

[Production method]

The optical glass of the present invention is produced, for example, as follows. In other words, the raw materials are uniformly mixed so that the respective components are within a specific content, and the produced mixture is poured into platinum crucible, quartz crucible or alumina crucible to be roughly melted, and then gold crucible, platinum rhodium, platinum is placed. Alloy bismuth or bismuth, melted in the temperature range of 900~1400 °C for 1 to 5 hours, stirred to homogenize and defoam, etc., and then reduced to a temperature below 1200 °C, then refined and stirred to remove The stripe was formed by molding using a molding die. Here, as a method of obtaining the glass to be formed by using the molding die, a method of flowing the molten glass to one end of the molding die while extracting the formed glass from the other end side of the molding die, or by a so-called primary pressing type (Direct Press) A method of forming a glass molded body, or a method of forming a glass molded body by casting molten glass into a mold and slowly cooling it as in so-called suspension molding.

[physical property]

The optical glass of the present invention preferably has a specific refractive index and dispersion (Abbe number).

Here, the lower limit of the refractive index (n _d ) of the optical glass of the present invention is preferably 1.50, more preferably 1.51, still more preferably 1.52. In particular, the lower limit of the refractive index (n _d ) of the first and second optical glasses may be preferably 1.70, more preferably 1.73, still more preferably 1.75, most preferably 1.77. Further, the lower limit of the refractive index (n _d ) of the fourth optical glass may be preferably 1.57, more preferably 1.60, most preferably 1.65. On the other hand, the upper limit of the refractive index (n _d ) of the optical glass of the present invention is not particularly limited, and is preferably 2.20 or less, more specifically 2.10 or less, and more specifically 2.00 or less. In particular, the upper limit of the refractive index (n _d ) of the third optical glass may be preferably 1.70, more preferably less than 1.70, most preferably 1.69.

The lower limit of the Abbe number (ν _d ) of the optical glass of the present invention is preferably 39, more preferably 40, still more preferably 41. In particular, the lower limit of the Abbe number (ν _d ) of the first and fourth optical glasses may be preferably 45, more preferably 47, and most preferably 49. Further, the lower limit of the Abbe number (ν _d ) of the third optical glass may be preferably 50, more preferably 52, and most preferably 53. On the other hand, the upper limit of the Abbe number (ν _d ) of the optical glass of the present invention is not particularly limited, and is approximately 63 or less, more specifically 61 or less, more specifically 60 or less, and more specifically 58. In the following, and more specifically, 57 or less. In particular, the upper limit of the Abbe number (ν _d ) of the second optical glass of the present invention may be preferably 52, more preferably 51, and most preferably 50.

Here, the Abbe number (ν _d ) of the second optical glass of the present invention is between the refractive index (n _d ) and preferably satisfies the relationship of (ν _d ) ≧ (-125 × n _d + 265). More preferably, it satisfies the relationship of (ν _d ) ≧ (-125 × n _{d +} 266), and the best is satisfying the relationship of (ν _d ) ≧ (-125 × n _{d +} 267).

Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably in a relationship with the refractive index (n _d ), preferably satisfying the relationship of (ν _d ) ≧ (-100 × n _d + 220), more preferably to meet _{(ν d) ≧ (-100 ×} n d +222) of the relationship, in order to meet the best _{(ν d) ≧ (-100 ×} n d +223) of the relationship. In particular, in the third optical glass, in the xy orthogonal coordinates having the Abbe number (ν _d ) as the x-axis and the refractive index (n _d ) as the y-axis, it is preferable to have A (50, 1.70). The Abbe number and the refractive index of the range surrounded by the four points of B (60, 1.60), C (63, 1.60), and D (63, 1.70).

By this, the degree of freedom in optical design is widened, and even if the element is made thinner, the amount of refraction of a large light can be obtained.

Further, the optical glass of the present invention has a high partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is such that (θg, F) 满足 (-0.00170 × ν _d + 0.6375) or (θg) is satisfied with the Abbe number (ν _d ). , F) ≧ (-2.0 × 10 ^-3 × ν _d + 0.6498) relationship. The optical glass of the present invention can obtain an optical glass having a higher partial dispersion ratio (?g, F) than a previously known glass containing a large amount of a rare earth element component. Therefore, the high refractive index and low dispersion of the glass are achieved, and the chromatic aberration of the optical element formed of the optical glass can also be reduced.

Here, the lower limit of the partial dispersion ratio (θg, F) of the first optical glass is preferably (-0.00170 × ν _d + 0.63750), more preferably (-0.00170 × ν _d + 0.63950), and most preferably (-0.00170) ×ν _d +0.64150). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the first optical glass is not particularly limited, and is, for example, (-0.00170 × ν _d + 0.65750), more preferably (-0.00170 × ν _d + 0.65550) The best is (-0.00170 × ν _d + 0.653750).

Further, the lower limit of the partial dispersion ratio (θg, F) of the second optical glass is preferably (-2.0 × 10 ^-3 × ν _d + 0.6498), more preferably (-2.0 × 10 ^-3 × ν _d + 0.6518) The best is (-2.0×10 ^-3 × ν _d +0.6558). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the second optical glass is not particularly limited, and is, for example, (-2.0 × 10 ^-3 × ν _d + 0.6950), more preferably (-2.0 × 10) ^-3 × ν _d + 0.6930), and the best is (-2.0 × 10 ^-3 × ν _d + 0.6910). Further, when the relationship between the partial dispersion ratio of the second optical glass and the Abbe number (ν _d ) is defined by a straight line parallel to the regular line, the partial dispersion ratio (θg, F) becomes, for example, (-1.7×10 ^{− 3} × ν _d + 0.63450) or more, more specifically (-1.7 × 10 ^-3 × ν _d + 0.63750) or more, more specifically (-1.7 × 10 ^-3 × ν _d + 0.63950) or more, and more specifically Introduction _{^{(-1.7 × 10 -3 × ν d}} +0.64150) over the majority of cases, for example, be _{^{(-1.7 × 10 -3 × ν d}} +0.67750) , more specifically (-1.7 × 10 ^-3 × ν _d +0.67550) Most of the following, and more specifically (-1.7×10 ^-3 × ν _d +0.67350) or less.

Further, the lower limit of the partial dispersion ratio (θg, F) of the third optical glass is preferably (-0.00170 × ν _d + 0.6375), more preferably (-0.00170 × ν _d + 0.6395), and most preferably (-0.00170 × ν _d +0.6415). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the third optical glass is not particularly limited, and is approximately (-0.00170 × ν _d + 0.6575), more specifically (-0.00170 × ν _d + 0.6555) In particular, (-0.00170 × ν _d + 0.6535) is the case.

Further, the lower limit of the partial dispersion ratio (θg, F) of the fourth optical glass is preferably (-0.00170 × ν _d + 0.6375), more preferably (-0.00170 × ν _d + 0.6395), and most preferably (-0.00170 × ν _d +0.6415). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the fourth optical glass is not particularly limited, and is approximately (-0.00170 × ν _d + 0.6800) or less, more specifically (-0.00170 × ν _d + 0.6790) Most of the following, and more specifically (-0.00170 × ν _d + 0.6780) or less. Further, the preferred range of the partial dispersion ratio in the present invention varies depending on the Abbe number of the optical glass, and is represented by a straight line parallel to the regular line.

The partial dispersion ratio (θg, F) of the optical glass of the present invention is measured based on the Japanese Optical Glass Industrial Association specification JOGIS01-2003. Further, the glass used in the measurement was obtained by subjecting the cooling rate of the cold cooling to -25 ° C / hr and treating it in a quench furnace.

Further, the optical glass of the present invention preferably has a glass transition point (Tg) of 650 ° C or lower. Thereby, extrusion molding at a lower temperature can be performed, so that the oxidation of the mold used in the press molding can be reduced to achieve a longer life of the mold. Therefore, the upper limit of the glass transition point (Tg) of the optical glass of the present invention is preferably 650 ° C, more preferably 620 ° C, and most preferably 600 ° C. Further, the lower limit of the glass transition point (Tg) of the optical glass of the present invention is not particularly limited, and the glass transition point (Tg) of the glass obtained by the present invention is approximately 100 ° C or higher, specifically 150 ° C or higher. More specifically, it is more than 200 ° C.

The glass transition point (Tg) of the optical glass of the present invention is carried out by using a differential thermal measuring device (NETZSCH-Ger) It is calculated by measuring the STA 409 CD) manufactured by tebau. Here, the sample particle size at the time of measurement was set to 425 to 600 μm, and the temperature increase rate was set to 10 ° C/min.

Further, the optical glass of the present invention preferably has less coloration. In the optical glass of the present invention, the glass having a thickness of 10 mm indicates that the wavelength (λ ₇₀ ) at which the spectral transmittance is 70% is 500 nm or less, more preferably 480 nm or less, as indicated by the transmittance of glass. Good is below 450 nm. In particular, in the optical glass of the present invention, the wavelength (λ ₈₀ ) indicating that the spectral transmittance is 80% in the sample having a thickness of 10 mm is preferably 500 nm or less, more preferably 480 nm or less, and most preferably 450 nm or less. . Further, in the optical glass of the present invention, the wavelength of 5% of the spectral transmittance (λ ₅ ) in the sample having a thickness of 10 mm is 450 nm or less, more preferably 430 nm or less, and most preferably 410 nm or less. Thereby, the absorption end of the glass is positioned in the vicinity of the ultraviolet region, and the transparency of the glass in the visible region is improved. Therefore, the optical glass can be used as a material of an optical element such as a lens.

The transmittance of the optical glass of the present invention is measured in accordance with the Japanese Optical Glass Industry Association specification JOGIS02. Specifically, for the opposite parallel polished product having a thickness of 10 ± 0.1 mm, the light transmittance of 200 to 800 nm is measured according to JIS Z8722, and λ ₈₀ (wavelength at a transmittance of 80%) and λ ₇₀ (penetration rate 70) are calculated. The wavelength at %) and λ ₅ (the wavelength at which the transmittance is 5%).

Further, the optical glass of the present invention preferably has a small photoelastic constant. In particular, in the optical glass of the present invention, the photoelastic constant (β) at a wavelength of 546.1 nm is 2.0 × 10 ^-5 nm ‧ cm ^-1 ‧ Pa ^-1 or less, more preferably 1.5 × 10 ^-5 nm ‧ cm ^-1 ‧ Pa ^-1 or less, more preferably 1.0 × 10 ^-5 nm ‧ cm ^-1 ‧ Pa ^-1 or less, and most preferably 0.7 × 10 ^-5 nm ‧ cm ^-1 ‧ Pa ^-1 or less Thereby, the partial dispersion ratio of the optical glass is improved, and the polarization characteristics of the transmitted light are also improved, so that when the optical glass is used in an optical system of a projector or a camera (especially including a polarizer), chromatic aberration is lowered, and It also suppresses the disordered reflection of light inside the optical element. That is, the color rendering properties in such projectors or cameras can be further improved.

The photoelastic constant (β) of the optical glass of the present invention is a specimen having a circular plate shape of a diameter of 25 mm and a thickness of 8 mm which is oppositely ground, and a compressive load of F [Pa] is applied in a specific direction, and the glass is measured at this time. The optical path difference δ [nm] of the light having a wavelength of 546.1 nm generated at the center. Then, using the values of the obtained F and δ and the thickness d [cm] of the glass, and calculating the photoelastic constant β [10 ^-5 nm‧cm ^-1 ‧Pa ^- according to the relationship of δ = β × d × F ¹ ]. Further, the measuring light source having a wavelength of 546.1 nm is an ultrahigh pressure mercury lamp.

Further, the optical glass of the present invention preferably has high resistance to devitrification. In particular, the optical glass of the present invention preferably has a lower liquidus temperature of 1200 ° C or lower. More specifically, the upper limit of the liquidus temperature of the optical glass of the present invention is preferably 1200 ° C, more preferably 1180 ° C, most preferably 1150 ° C. Thereby, the stability of the glass is improved and the crystallization is lowered. Therefore, the devitrification resistance when the glass is formed from the molten state can be improved, and the influence of the optical element using the glass on the optical characteristics can be reduced. On the other hand, the lower limit of the liquidus temperature of the optical glass of the present invention is not particularly limited, and the liquid phase temperature of the glass obtained by the present invention is approximately 500 ° C or higher, specifically 550 ° C or higher, and more specifically 600. Most cases above °C. In addition, the "insulation test" in the present specification is carried out by confirming that the glass has a high resistance to devitrification, and the glass material is placed in a 30 cc platinum crucible, and the lid is closed at 1200. Dissolve in a furnace of °C~1250 °C for about 10~20 minutes, stir it to homogenize, and then cover the glass in the furnace set to 1000~1150 °C for 2 hours, observe the surface and interior of the glass. And the crystals deposited on the contact surface with the inner wall of the crucible.

[Preforms and optical components]

From the optical glass to be produced, for example, a glass molded body can be produced by a method such as press molding such as reheat extrusion molding or precision extrusion molding. In other words, a preform for press molding can be produced from optical glass, and the preform can be subjected to reheat extrusion molding, followed by polishing to prepare a glass molded body, or, for example, a preform produced by polishing. The glass molded body was produced by precision extrusion molding. Furthermore, the method of producing a glass molded body is not limited to these methods.

The glass forming system thus produced is effectively utilized for various optical elements, and among them, it is particularly preferably used for optical elements such as lenses or iridium. Thereby, the color blur caused by the chromatic aberration in the transmitted light of the optical system provided with the optical element is reduced. Therefore, when the optical element is used in a camera, the object to be imaged can be more accurately displayed, and when the optical element is used in a projector, the desired image can be projected with higher brightness.

[Examples]

Examples of the present invention (No. A1 to No. A13, No. B1 to No. B23, No. C1 to No. C6, No. D1 to No. D36) and comparative examples (No. a1, No. c1) Composition of No. d1), and refractive index (n _d ) and Abbe number (ν _d ) of the glass, partial dispersion ratio (θg, F), glass transition point (Tg), and transmittance of 80% The values of the wavelength (λ ₈₀ ), the wavelength at which the transmittance is 5% (λ ₅ ), and the liquidus temperature are shown in Tables 1 to 11. Furthermore, the following examples are merely illustrative and are not limited to the embodiments.

Optical glass and comparative examples (No. a1, No) of Examples (No. A1 to No. A13, No. B1 to No. B23, No. C1 to No. C6, No. D1 to No. D36) of the present invention The glass of c1 and No. d1) is used as a raw material of each component, and is used in a usual optical glass such as an oxide, a hydroxide, a carbonate, a nitrate, a fluoride, a hydroxide or a metaphosphoric acid compound. The high-purity raw material is weighed and uniformly mixed in such a manner as to achieve the ratio of the composition of each of the examples and the comparative examples shown in Tables 1 to 11, and then introduced into the platinum crucible according to the melting difficulty of the glass composition. Dissolve in an electric furnace at a temperature of 1000 to 1400 ° C for 1 to 6 hours, stir to homogenize it, defoam, etc., then lower the temperature to 1200 ° C or lower, stir and homogenize, and then cast into a mold. Slowly cool to make glass.

Here, examples (No. A1 to No. A13, No. B1 to No. B23, No. C1 to No. C6, No. D1 to No. D36) and comparative examples (No. a1, No. c1) The refractive index (n _d ) and the Abbe number (ν _d ) and the partial dispersion ratio (θg, F) of the glass of No. d1) were measured based on the Japanese Optical Glass Industry Association specification JOGIS01-2003. Then, with respect to the calculated values of Abbe's number (ν _d ) and partial dispersion ratio (θg, F), the relationship a (θg, F) = -a × ν _d + b is calculated as a slope a of 0.0017 and 0.0020. Intercept b. Further, regarding the value of the calculated refractive index (n _d ), the value of the relation -100 × n _d + 220 is calculated. Further, the glass used in the measurement was obtained by subjecting the cooling rate of the cold cooling to -25 ° C / hr and treating it in a quench furnace.

Further, in the examples (No. D1 to No. D36) and the glass transition point (Tg) of the glass of the comparative example (No. d1), the differential heat measuring device (NETZSCH-Ger) was used. It is calculated by measuring the STA 409 CD) manufactured by tebau. Here, the sample particle size at the time of measurement was set to 425 to 600 μm, and the temperature increase rate was set to 10 ° C/min.

In addition, the transmittance of the glass of the examples (No. D1 to No. D36) and the comparative example (No. d1) was measured in accordance with the Japanese Optical Glass Industry Association specification JOGIS02. Further, in the present invention, the transmittance of the glass is measured, thereby calculating the presence or absence of the color of the glass. Specifically, for the opposite parallel polished product having a thickness of 10 ± 0.1 mm, the light transmittance of 200 to 800 nm is measured according to JIS Z8722, and the wavelength (λ ₈₀ ) and λ ₅ (penetration rate 5) at a transmittance of 80% are calculated. The wavelength at %).

Further, the liquidus temperatures of the glasses of the examples (No. D1 to No. D36) and the comparative examples (No. d1) were measured by placing the pulverized glass samples at intervals of 10 mm. The platinum plate was taken out in a furnace inclined at a temperature of 800 ° C to 1200 ° C for 30 minutes, and after cooling, the presence or absence of crystals in the glass sample was observed with a microscope at a magnification of 80 times. At this time, as a sample, the optical glass was pulverized into a granular shape having a diameter of about 2 mm.

The partial dispersion ratio (θg, F) of the optical glass of the embodiment of the present invention is (-0.00170 × ν _d + 0.6375) or more, more specifically (-0.00170 × ν _d + 0.6420) or more. In particular, the portion of the optical glass of Example (No. C1 ~ No. C6) The dispersion ratio (θg, F) of (-0.00170 × ν _d +0.64486) above. Further, the partial dispersion ratio (θg, F) of the optical glass of the examples (No. A1 to No. A13) of the present invention is also (-0.00170 × ν _d + 0.63750) or more, and it is estimated that the desired portion is higher. Dispersion ratio. On the other hand, the partial dispersion ratio (θg, F) of the optical glass of the examples (No. B1 to No. B23) of the present invention is (-0.00200 × ν _d + 0.64982) or more. Therefore, it is clear that the partial dispersion ratio (θg, F) of the optical glass system and the Abbe number (ν _d ) in the embodiment of the present invention is large, and the chromatic aberration when the optical element is formed is small.

The refractive index (n _d ) of the optical glass of the embodiment of the present invention is 1.57 or more, more specifically 1.65 or more, and the refractive index (n _d ) is 2.20 or less, and more specifically 1.85 or less. Within the scope of the need. In particular, the refractive index (n _d ) of the optical glass of the examples (No. A1 to No. A13) of the present invention is 1.73 or more, and the refractive index (n _d ) is 1.78 or less. Further, the refractive index (n _d ) of the optical glass of the examples (No. B1 to No. B23) of the present invention is 1.70 or more, and more specifically 1.75 or more. Further, the refractive index (n _d ) of the optical glass of the examples (No. C1 to No. C6) was 1.60 or more, more specifically 1.65 or more, and the refractive index (n _d ) was 1.70 or less. And index optical glass, Example (No. D1 ~ No. D36) of the (n _d) are less than 1.69, and the refractive index (n _d) of 1.81 or less.

Further, the optical glass of the embodiment of the present invention has an Abbe number (ν _d ) of 39 or more, more specifically 40.7 or more, and the Abbe number (ν _d ) is 63 or less, and more specifically 61. Below, within the required range. In particular, the Abbe number (ν _d ) of the optical glass of the embodiment (No. A1 to No. A13) of the present invention is 45 or more, more specifically 49 or more, and the Abbe number (ν _d ) It is 60 or less, and more specifically 54 or less. Further, the Abbe's number (ν _d ) of the optical glass of the examples (No. B1 to No. B23) of the present invention is 39 or more, more specifically 40.7 or more, and the Abbe number (ν _d ) is not Up to 52, in more detail below 51.3. Further, the Abbe's number (ν _d ) of the optical glass of the embodiment (No. C1 to No. C6) of the present invention is 50 or more, more specifically 54 or more, and the Abbe number (ν _d ) is 57 or less. Further, the optical glass of the Abbe Example (No. D1 ~ No. D36) of the present invention the number (ν _d) are 45 or more, and the Abbe number (ν _d) of 63 or less, more precisely, 61 or less.

Here, in the optical glass of the embodiment (No. C1 to No. C6) of the present invention, the Abbe number (ν _d ) of the optical glass of the present invention is satisfied with the refractive index (n _d ) (ν) _d ) The relationship between ≧ (-100 × n _d + 220).

Further, the glass transition point (Tg) of the optical glass of the examples (No. D1 to No. D36) of the present invention is 650 ° C or lower, and more specifically 620 ° C or lower, within a desired range. Further, it is estimated that the glass transition point (Tg) of the optical glass of the other embodiment of the present invention is also 650 ° C or lower.

And, (when the wavelength transmittance of 80%) [lambda] The optical glass ₈₀ Example (No. D1 ~ No. D36) of the present invention are 500 nm or less, more precisely, 410 nm or less. Further, in the optical glass of the embodiment (No. D1 to No. D36) of the present invention, λ ₅ (wavelength at a transmittance of 5%) is 450 nm or less, and more specifically 350 nm or less. Within the scope. Further, it is presumed that the optical glass of λ ₇₀ (wavelength at a transmittance of 70%) of other embodiments of the present invention is also 500 nm or less, and λ ₅ (wavelength at a transmittance of 5%) is also 450 nm. the following.

Further, in the optical glass of the examples (No. D1 to No. D36) of the present invention, the liquidus temperature is 1200 ° C or lower, more specifically 1,100 ° C or lower, and the liquidus temperature is 500 ° C or higher. On the other hand, the liquid phase temperature of the glass of the comparative example (No. d1) was 1200 ° C or more. Therefore, it is clear that the optical glass system of the embodiment of the present invention has a liquidus temperature lower than that of the glass of the comparative example and is difficult to devitrify.

Further, it is estimated that the photoelastic constant (β) of the optical glass system at a wavelength of 546.1 nm in the examples (No. A1 to No. A13) of the present invention is 2.0 × 10 ^-5 nm ‧ cm ^-1 ‧ Pa ^-1 or less.

Therefore, it is clear that the optical glass system refractive index (n _d ) and the Abbe number (ν _d ) of the embodiment of the present invention are within a desired range, and the chromatic aberration is small, and it is easy to perform press molding, and the visible region wavelength The transparency of light is high. In particular, it is also clear that the optical glass of the examples (No. D1 to No. D36) of the present invention has high resistance to devitrification. Further, it is considered that the disordered reflection inside the optical glass-based optical glass of the examples (No. A1 to No. A13) is also small.

Further, the optical glass obtained in the examples of the present invention is subjected to reheat extrusion molding, and then ground and polished to form a lens and a crucible. Further, the optical glass of the embodiment of the present invention is used to form a preform for precision extrusion molding, and a precision extrusion molding process is performed on the preform for precision extrusion molding. In either case, the problem of opalescence and devitrification does not occur in the glass after heating and softening, and it can be stably processed into various lenses and shapes of the crucible.

The present invention has been described in detail above with reference to the preferred embodiments of the present invention.

Fig. 1 is a view showing a partial dispersion ratio (θg, F) as a vertical axis and an Abbe number (ν _d ) as a normal line indicated by orthogonal coordinates on the horizontal axis.

(no component symbol description)

Claims (35)

An optical glass containing 5.0 to 50.0% of a B ₂ O ₃ component, 10.0 to 55.0% of a La ₂ O ₃ component, and a content of a SiO ₂ component of 15.0% by mass based on the total mass of the glass in terms of an oxide conversion composition. The content of the Ta ₂ O ₅ component is 10.0% or less, and the content of the F component is more than 0% and 30.0% or less, and the optical glass has a refractive index of 1.57 or more. (n _d) of over 39 and the number (ν _d) Abbe, partial dispersion ratio (θg, F) and Abbe number between the line (ν _d) satisfies (θg, F) ≧ (-0.00170 × ν d + 0.63750) or (θg, F) ≧ (-2.0 × 10 ^-3 × ν _d + 0.6498). The optical glass of claim 1, which has a refractive index (n _d ) of 1.73 or more and an Abbe number (ν _d ) of 45 or more, and a partial dispersion ratio (θg, F) and an Abbe number (ν _d ) are satisfied. (θg, F) ≧ (-0.00170 × ν _d + 0.63750). The optical glass of claim 1, which has an Abbe number (ν _d ) of less than 39 and less than 52, and a partial dispersion ratio (θg, F) and an Abbe number (ν _d ) satisfy (θg, F) ≧ ( -2.0×10 ^-3 ×ν _d +0.6498). An optical glass according to claim 1, which has an A(50, 1.70), B in an xy orthogonal coordinate having an Abbe number (ν _d ) as an x-axis and a refractive index (n _d ) as a y-axis. The Abbe number and the refractive index of the range surrounded by the four points of 60, 1.60, C (63, 1.60), D (63, 1.70). The optical glass of claim 1, wherein the oxide-converted composition further comprises an Al ₂ O ₃ component. The optical glass of claim 1, wherein the content of the Al ₂ O ₃ component is 20.0% or less by mass% based on the total mass of the glass of the oxide conversion composition. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (SiO ₂ + B ₂ O ₃ ) are 40.0% or less. The optical glass of claim 1, wherein the Gd ₂ O ₃ component is 0 to 40.0% and/or the Y ₂ O ₃ component is 0 to 20.0% and/or Yb in terms of mass% relative to the total mass of the oxide-converted composition. ₂ O ₃ component 0~20.0% and/or Lu ₂ O ₃ component 0~20.0%. The optical glass of claim 1, wherein the Ln is selected from the group consisting of La, Gd, Y, Yb, and Lu, and the Ln ₂ O ₃ component (in the formula, Ln is selected from the group consisting of La, Gd, Y, Yb, and Lu). The quality of the sum is 80.0% or less. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (Gd ₂ O ₃ + Yb ₂ O ₃ ) are 26.0% or less. The optical glass of claim 1, wherein the mass ratio of the oxide-converted composition is Ln ₂ O ₃ /(Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ +Ta ₂ O ₅ ) is 1.7 or more and 25.0 or less ( In the formula, Ln is selected from one or more of the group consisting of La, Gd, Y, Yb, and Lu). The optical glass of claim 1, wherein the mass ratio of the oxide-converted composition is Ln ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) of 1.00 or more (wherein Ln is selected from La, Gd, Y, Yb, Lu) One or more of the group consisting of). The optical glass of claim 1, which further comprises, by mass%, the Bi ₂ O ₃ component 0 to 10.0% and/or the TiO ₂ component 0 to 15.0% and/or Nb, based on the total mass of the glass in terms of oxide conversion composition. ₂ O ₅ components 0 to 20.0% and/or WO ₃ components 0 to 15.0% and/or K ₂ O components 0 to 10.0% of each component. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) are 0.1% or more and 30.0 %the following. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ ) are 20.0% or less. The optical glass of claim 1, wherein the mass ratio F/(F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) in the oxide-converted composition is 0.36 or more and 1.00 or less. The optical glass of claim 1, which further comprises, by mass%, a ZrO ₂ component of 0 to 15.0%, based on the total mass of the glass in terms of an oxide conversion composition. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (WO ₃ + La ₂ O ₃ + ZrO ₂ + Ta ₂ O ₅ ) are 10.0% or more and 60.0% or less. The optical glass of claim 1, wherein the mass of the total mass of the glass relative to the oxide-converted composition and (Bi ₂ O ₃ +TiO ₂ +WO ₃ +Nb ₂ O ₅ +Ta ₂ O ₅ ) are more than 0%. The optical glass of claim 1, wherein the content of the Li ₂ O component is 15.0% or less by mass% based on the total mass of the glass of the oxide conversion composition. The optical glass of the requested item 1, wherein the composition in terms of oxide mass ratio of _{(Ta 2 O 5 + ZrO 2} + Li 2 O) / (F + Bi 2 O 3 + TiO 2 + WO 3 + Nb 2 O 5 + K ₂ O) is 2.00 or less. The optical glass of claim 1, wherein the mass ratio of the oxide-converted composition is (F + Bi ₂ O ₃ + TiO ₂ + WO ₃ + Nb ₂ O ₅ + K ₂ O) / (Ta ₂ O ₅ + ZrO ₂ + Li ₂ O) is 0.50 or more. The optical glass of claim 1, which further comprises, by mass%, MgO component 0~20.0% and/or CaO component 0~40.0% and/or SrO component 0~40.0. % and/or BaO components 0 to 55.0% of each component. The optical glass of claim 1, wherein the mass of the RO component (in the formula, R is selected from one or more of the group consisting of Mg, Ca, Sr, and Ba) relative to the total mass of the oxide-converted composition is 55.0% or less. The optical glass of claim 1, wherein the content of the Na ₂ O component is 20.0% or less based on the mass % of the total mass of the glass in terms of oxide composition. The optical glass of claim 1, wherein the mass of the Rn ₂ O component (wherein Rn is selected from the group consisting of Li, Na, and K) of the total mass of the oxide-converted composition is 25.0% or less. An optical glass according to claim 1, wherein the composition is converted relative to the oxide The total mass of the glass is, in mass%, the content of the ZnO component is 30.0% or less. The optical glass of claim 1, which further comprises, by mass%, GeO ₂ component 0 to 10.0% and/or P ₂ O ₅ component 0 to 10.0% and/or Ga, relative to the total mass of the glass in terms of oxide conversion composition. ₂ O ₃ component 0 to 10.0% and/or TeO ₂ component 0 to 10.0% and/or SnO ₂ component 0 to 5.0% and/or Sb ₂ O ₃ component 0 to 1.0%. The requested item 1 of the optical glass, having a refractive index of 1.57 or more of the (n _d) of 45 or more and Abbe's number (ν _d). The optical glass of claim 1, wherein the relationship between the Abbe number (ν _d ) and the refractive index (n _d ) satisfies ν _d ≧ -100 × n _d +220. The optical glass of claim 1, wherein the relationship between the Abbe number (ν _d ) and the refractive index (n _d ) satisfies ν _d ≧ - 125 × n _d + 265. A preformed body comprising the optical glass of claim 1. An optical component produced by extrusion molding a preformed body as claimed in claim 32. An optical element comprising the optical glass of claim 1 as a base material. An optical machine comprising an optical component as claimed in claim 33 or 34.