Optical glass, optical element, light guide plate, and wearable image-display device

Abstract

Provided is an optical glass that has both a high refractive index and a high light transmittance and is excellent in mass productivity. The optical glass contains, in terms of mass%, 0-15% SiO2, 5-40% TiO2, and 5-50% La2O3; has a mass ratio of (Nb2O5 + La2O3) / TiO2 of 1.5 or greater; and has a refractive index nd of 2.03 or greater.

Description

Optical glass, optical elements, light guide plates, and wearable image display devices

[0001] The present invention relates to optical glass used as a light guide plate or the like in a wearable image display device.

[0002] Glass is used as a component of wearable image display devices such as projector glasses, eyeglass-type or goggle-type displays, virtual reality (VR) or augmented reality (AR) display devices, and virtual image display devices. The glass functions, for example, as a see-through light guide plate, allowing a user to view an image displayed on the glass while looking at the outside scenery through the glass. Furthermore, it is also possible to realize a 3D display by utilizing technology that projects different images on the left and right sides of the glasses, or to realize a virtual reality space by utilizing technology that connects the image to the retina using the lens of the eye. The glass is required to have a high refractive index and high light transmittance in order to achieve a wider angle of view, higher brightness and contrast, improved light guide properties, and the like (see, for example, Patent Document 1).

[0003] JP 2017-32673 A

[0004] However, generally, increasing the refractive index tends to decrease the light transmittance, and therefore, from the viewpoint of improving the performance of light guide plates, there is a demand for optical glass that has both a high refractive index and high light transmittance.

[0005] Generally, increasing the refractive index of glass tends to make vitrification unstable.

[0006] In view of the above, an object of the present invention is to provide an optical glass that has both a high refractive index and high light transmittance and is suitable for mass production.

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by providing an optical glass with a specific composition. ２ 0-15%, TiO ２ 5-40%, La ２ O ３ 5 to 50%, in mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO２ The refractive index nd is 1.5 or more, and the refractive index nd is 2.03 or more.

[0008] The optical glass of embodiment 2 contains, in mass %, SiO ２ 0-15%, TiO ２ 5 to less than 20%, La ２ O ３ 8-50%, Nb ２ O ５ 2-30%, Gd ２ O ３ 0-15%, BaO 0-less than 10%, B ２ O ３ 0-0.1%, Al ２ O ３ 0-5%, MgO+CaO+SrO+BaO+ZnO 0-10%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) 3.500 or more.

[0009] The optical glass of embodiment 3 contains, in mass %, SiO ２ 0-15%, TiO ２ 20-40%, La ２ O ３ 5-50%, B ２ O ３ 0-2.5%, Al ２ O ３ 0 to 3%, MgO+CaO+SrO+BaO+ZnO 0.1% or more, Li ２ O + Na ２ O+K ２ O 0 to 2%, and by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２1.5 or more, TiO ２ / ZrO ２ 2.9 or more, (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) 0.4 or less, B ２ O ３ / La ２ O ３ It is characterized in that the ratio is 0.10 or less.

[0010] The optical glass of embodiment 4 is SiO ２ , TiO ２ , La ２ O ３ , Nb ２ O ５ and ZrO ２ as an essential component, and in mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ It is characterized in that it is 0.001 or more.

[0011] The optical glass of Aspect 5 is any one of Aspects 1 to 3, further comprising, in mass ratios, HfO ２ / TiO ２ It is preferably 0.001 or more.

[0012] The optical glass of Aspect 6 is any one of Aspects 1 to 5, and preferably has an Abbe number νd of 30 or less.

[0013] The optical glass of Aspect 7 is any one of Aspects 1 to 6, and has an internal transmittance τ at a wavelength of 450 nm at a thickness of 10 mm. ４５０ is preferably 70% or more.

[0014] The optical glass of Aspect 8 is any one of Aspects 1 to 7, wherein the density is 6.0 g / cm ３ It is preferable that:

[0015] The optical glass of Aspect 9 is any one of Aspects 1 to 8, and is preferably in the form of a plate having a thickness of 1 mm or less.

[0016] In the optical glass of Aspect 10, in Aspect 9, the major surface preferably has a major axis of 100 mm or more.

[0017] The optical element of Aspect 11 is characterized in that it is made of the optical glass of any one of Aspects 1 to 10.

[0018] The light guide plate of Aspect 12 is characterized in that it is made of the optical glass of any one of Aspects 1 to 10.

[0019] The light guide plate of Aspect 13 is preferably used in a wearable image display device selected from projector-equipped glasses, eyeglass-type or goggle-type displays, virtual reality or augmented reality display devices, and virtual image display devices in Aspect 12.

[0020] The wearable image display device of Aspect 14 preferably includes the light guide plate of Aspect 12 or Aspect 13.

[0021] According to the present invention, an optical glass can be provided which has both a high refractive index and a high light transmittance and is suitable for mass production.

[0022] The reasons for limiting the glass composition of the optical glass of the present invention will be explained below. In the following explanation of the content of each component, unless otherwise specified, "%" means "% by mass," and "x + y" means the total amount of x and y. Furthermore, "x / y" means the value (mass ratio) obtained by dividing the content of x by the content of y.

[0023] <Optical Glass A> In one embodiment, the optical glass of the present invention contains, in mass %, SiO ２ 0-15%, TiO ２ 5-40%, La ２ O ３ 5 to 50%, in mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２The optical glass A is characterized by having a refractive index nd of 1.5 or more and a refractive index nd of 2.03 or more.

[0024] SiO ２ is a glass framework component that improves the stability of vitrification. It is also a component that tends to lower the thermal expansion coefficient of glass. ２ The content of is preferably 0 to 15%. More specifically, SiO ２ The lower limit of the content of SiO is preferably 0% or more, 1% or more, 2% or more, 2.5% or more, 4% or more, 5% or more, and particularly preferably 6% or more. ２ The upper limit of the content of SiO is preferably 15% or less, 12% or less, and particularly preferably 11% or less. ２ If the content of SiO is too high, the melting temperature tends to be high, and transition metal components such as Nb and Ti are reduced, causing absorption in the visible range (producing a reduction color), which tends to reduce the internal transmittance of the glass. In other words, the light transmittance in the visible range tends to decrease. In addition, the refractive index tends to decrease. From the viewpoint of improving the stability of vitrification, SiO ２ It is preferable that the above-mentioned component is contained as an essential component.

[0025] TiO ２ is an essential component that increases the refractive index of glass. It is also an effective component for reducing the density of glass. ２ The content of TiO is preferably 5 to 40%. ２ The lower limit of the content of TiO is preferably 5% or more, 5.5% or more, 10% or more, 14% or more, 15% or more, and particularly preferably 16% or more. ２ The upper limit of the content of TiO is preferably 40% or less, 35% or less, and particularly preferably 30% or less. ２ If the content of TiO is too small, it becomes difficult to obtain the above effect. ２ If the content of TiO is too high, vitrification becomes difficult, and in addition, the influence of the reduction color becomes large when the glass is reduced, and the light transmittance in the visible region tends to decrease. Therefore, from the viewpoint of increasing the light transmittance in the visible region in particular, it is preferable to use TiO ２ The content of TiO is preferably 5 to less than 20%, particularly preferably 5 to 19.9%. ２The content is preferably 20 to 40%, particularly preferably 23 to 40%.

[0026] La ２ O ３ is an essential component that increases the refractive index and improves the stability of vitrification. ２ O ３ The content of La is preferably 5 to 50%. ２ O ３ The lower limit of the content of La is preferably 5% or more, 7.5% or more, 8% or more, 10% or more, 14% or more, 15% or more, 18% or more, 20% or more, 22% or more, 25% or more, 26% or more, and particularly preferably 30% or more. ２ O ３ The upper limit of the content of La is preferably 50% or less, 48% or less, particularly preferably 45% or less. ２ O ３ If the content of La is too small, it becomes difficult to obtain the above-mentioned effects. ２ O ３ If the content is too high, vitrification becomes unstable, which tends to make mass production difficult. In addition, the density tends to be high.

[0027] Nb ２ O ５ is a component that significantly increases the refractive index of the glass. ２ O ５ The content of Nb is preferably 0 to 30%. ２ O ５ The lower limit of the Nb content is preferably 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, and particularly preferably 5% or more. ２ O ５ The upper limit of the Nb content is preferably 30% or less, 25% or less, 20% or less, 18% or less, particularly preferably 16% or less. ２ O ５ If the content of Nb is too high, vitrification becomes difficult. ２ O ５ It is preferable that the above-mentioned component is contained as an essential component.

[0028] From the viewpoint of increasing the refractive index of the glass, Nb ２ O ５ +La ２ O ３The content of Nb ２ O ５ and La ２ O ３ The total amount of Nb is preferably 7.5% or more, 10% or more, 15% or more, 20% or more, 21% or more, 24% or more, 25% or more, 30% or more, 35% or more, and particularly preferably 40% or more. ２ O ５ +La ２ O ３ If the content of Nb is too small, it becomes difficult to obtain the above effect. ２ O ５ +La ２ O ３ The upper limit of the content is preferably 80% or less, 75% or less, 70% or less, 65% or less, and particularly preferably 60% or less.

[0029] In mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ is preferably 1.5 or more, 1.51 or more, particularly preferably 1.55 or more. ２ O ３ and / or Nb ２ O ５ and TiO ２ When TiO is contained, ２ If the ratio is too high, TiO ２ Therefore, devitrification products containing Nb ２ O ５ +La ２ O ３ ) / TiO ２ By setting the value to the above range, it becomes easier to obtain a stable glass with a high refractive index. ２ O ５ +La ２ O ３ ) / TiO ２ The upper limit of is preferably 10 or less, 8 or less, 6 or less, and particularly preferably 3 or less. ２ O ５ +La ２ O ３ ) / TiO ２ " is Nb ２ O ５ +La２ O ３ The content of TiO ２ The value is calculated by dividing the content by the total amount of the compound.

[0030] In addition to the above, the optical glass A may have the following configuration.

[0031] From the viewpoint of increasing the refractive index of the glass and decreasing the density, TiO ２ +Nb ２ O ５ The content of (TiO ２ and Nb ２ O ５ The total amount of TiO is preferably 5% or more, 7% or more, 7.5% or more, 10% or more, 15% or more, 20% or more, 21% or more, 24% or more, and particularly preferably 25% or more. ２ +Nb ２ O ５ If the content is too small, it becomes difficult to obtain the above effect. ２ +Nb ２ O ５ The upper limit of the content is preferably 60% or less, 50% or less, and particularly preferably 40% or less.

[0032] ZrO ２ is a component that easily increases the refractive index. ２ The content of ZrO is preferably 0 to 15%. ２ The lower limit of the content of ZrO is preferably 0% or more, 1% or more, or 2% or more. ２ The upper limit of the content of ZrO is preferably 15% or less, 12% or less, 10% or less, and particularly preferably 9% or less. ２ If the content is too high, vitrification becomes unstable. ２ It is preferable that the above-mentioned component is contained as an essential component.

[0033] Gd ２ O ３ is a component that increases the refractive index and improves the stability of vitrification. ２ O ３ The content of is preferably 0 to 20%. ２ O ３The lower limit of the Gd content is preferably 0% or more, 1% or more, and particularly preferably 2% or more. ２ O ３ The upper limit of the Gd content is preferably 20% or less, 15% or less, 13% or less, 10% or less, 7% or less, and particularly preferably 6% or less. ２ O ３ If the content is too high, the vitrification tends to become unstable, which makes mass production difficult. In addition, the density tends to increase.

[0034] Y ２ O ３ is a component that increases the refractive index and chemical durability, and also increases Young's modulus. ２ O ３ The content of Y is preferably 0 to 15%. ２ O ３ The lower limit of the content of Y is preferably 0% or more, 0.1% or more, 1% or more, and particularly preferably 2% or more. ２ O ３ The upper limit of the content of Y is preferably 15% or less, 12% or less, 10% or less, 7% or less, and particularly preferably 5% or less. ２ O ３ If the content is too high, the melting temperature tends to be high and the vitrification tends to be unstable.

[0035] Yb ２ O ３ is a component that increases the refractive index. ２ O ３ The content of is preferably 0 to 15%. ２ O ３ The lower limit of the content of Yb is preferably 0% or more, 0.1% or more, 1% or more, 2% or more, 2.5% or more, and particularly preferably 3% or more. ２ O ３ The upper limit of the content of Yb is preferably 15% or less, 12% or less, 10% or less, 9% or less, particularly preferably 7% or less. ２ O ３ If the content is too high, the density of the glass tends to increase, and devitrification and striae tend to occur.

[0036] From the viewpoint of improving the stability of vitrification, La ２ O ３ +Gd２ O ３ +Y ２ O ３ +Yb ２ O ３ The content of (La ２ O ３ , Gd ２ O ３ , Y ２ O ３ and Yb ２ O ３ The total amount of La is preferably 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, and particularly preferably 35% or more. ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ If the content of La is too small, it becomes difficult to obtain the above effect. ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The upper limit of the content is preferably 79.9% or less, 75% or less, 70% or less, 65% or less, 60% or less, and particularly preferably 55% or less.

[0037] WO ３ is a component that easily stabilizes vitrification. ３ The content of WO is preferably 0 to 15%. ３ The lower limit of the content of WO is preferably 0% or more, particularly preferably 0.1% or more. ３ The upper limit of the content of WO is preferably 15% or less, 12% or less, 10% or less, 5% or less, less than 3%, 2% or less, particularly preferably 1% or less. ３ If the content is too high, the light transmittance tends to decrease, and the density tends to increase.

[0038] HfO ２ is a component that increases the crystallization temperature and improves the devitrification resistance of the glass. ２ The content of is preferably 0 to 1%. More specifically, HfO２ The lower limit of the content of HfO is preferably 0% or more, 0.01% or more, particularly preferably 0.05% or more. ２ The upper limit of the content of HfO is preferably 1% or less, 0.8% or less, 0.5% or less, 0.3% or less, particularly preferably 0.2% or less. ２ If the content is too high, the density tends to be high.

[0039] Ta ２ O ５ is a component that increases the refractive index, but if its content is too high, phase separation and devitrification tend to occur. ２ O ５ Since Ta is an expensive component, if its content increases, the raw material cost will increase. ２ O ５ The upper limit of the content is preferably 15% or less, 12% or less, 10% or less, 5% or less, 3% or less, or 1% or less, and is particularly preferably substantially not contained. ２ O ５ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Ta is preferably 0% or more. ２ O ５ The lower limit of the content of each of the above components may be 0.01% or more. Here, in this specification, "substantially not contained" means that the component is not intentionally contained as a raw material, and does not exclude the inclusion of unavoidable impurities. Objectively, it means that the content of each of the above components is less than 0.01%.

[0040] MgO, CaO, and SrO are components that stabilize vitrification, but if their contents are too high, the refractive index tends to decrease. Therefore, the content of MgO + CaO + SrO (the total amount of MgO, CaO, and SrO) is preferably 0 to 15%. More specifically, the upper limit of the content of MgO + CaO + SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of MgO + CaO + SrO is preferably 0% or more. However, from the viewpoint of stabilizing vitrification, the lower limit of the content of MgO + CaO + SrO may be 0.01% or more, and particularly 0.02% or more. Note that the upper limit of the content of each of MgO, CaO, and SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of each of MgO, CaO and SrO may be set to 0.01% or more, particularly 0.02% or more.

[0041] BaO is a component that increases the refractive index and stabilizes vitrification, but if its content is too high, vitrification tends to become unstable. It also tends to reduce the Abbe number. Therefore, the BaO content is preferably 0 to 15%. More specifically, the upper limit of the BaO content is preferably 15% or less, 14% or less, 12% or less, or 11% or less, particularly preferably less than 10%, and the lower limit of the BaO content is preferably 0% or more. However, from the viewpoint of increasing the refractive index, the lower limit of the BaO content may be 0.1% or more, 0.5% or more, 1% or more, particularly 2% or more.

[0042] ZnO is a component that tends to improve the stability of vitrification. The ZnO content is preferably 0 to 15%. More specifically, the lower limit of the ZnO content is preferably 0% or more, particularly 0.1% or more, and the upper limit of the ZnO content is preferably 15% or less, 12% or less, 10% or less, particularly 8% or less. If the ZnO content is too high, the refractive index tends to decrease.

[0043] From the viewpoint of increasing the refractive index, the content of MgO+CaO+SrO+BaO+ZnO (the total amount of MgO, CaO, SrO, BaO, and ZnO) is preferably 0 to 15%. More specifically, the upper limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 15% or less, 12% or less, and particularly preferably 10% or less, and the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0% or more. However, when emphasis is placed on stabilizing vitrification and reducing density, the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0.1% or more, and particularly preferably 0.2% or more.

[0044] Li ２ O, Na ２ O and K ２ O can be contained for the purpose of adjusting the melt viscosity, but if the content is too high, the vitrification may become unstable and the refractive index may decrease. ２ O + Na ２ O+K ２ O content (Li ２ O, Na ２ O and K ２ The total amount of Li and O is preferably 0 to 2%. ２ O + Na ２ O+K ２ The upper limit of the O content is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is substantially not contained. ２ O + Na ２ O+K ２ The lower limit of the O content is preferably 0% or more. However, when O is intentionally contained for the purpose of adjusting the melt viscosity, Li ２ O + Na ２ O+K ２ The lower limit of the O content may be set to 0.01% or more. ２ O, Na ２ O and K ２ The upper limit of the content of each component of O is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is not substantially contained. ２ O, Na ２ O and K ２The lower limit of the content of each component of O is preferably 0% or more. On the other hand, when it is intentionally contained for the purpose of adjusting the melt viscosity, Li ２ O, Na ２ O and K ２ The lower limit of the content of each of the O components may be set to 0.01% or more.

[0045] B ２ O ３ is a component that contributes to the stability of vitrification, but if its content is too high, the refractive index tends to decrease. ２ O ３ The content of B is preferably 0 to 15%. ２ O ３ The upper limit of the content of is preferably 15% or less, 10% or less, 9% or less, 5% or less, particularly preferably 2.5% or less; ２ O ３ The lower limit of the content of B is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more, particularly 0.1% or more.

[0046] From the viewpoint of increasing the refractive index while suppressing a decrease in light transmittance in the visible range, SiO ２ +B ２ O ３ Content (SiO ２ and B ２ O ３ The total amount of SiO is preferably 0 to 15%. ２ +B ２ O ３ The upper limit of the content of SiO is preferably 15% or less, 10% or less, particularly preferably 9.4% or less. ２ +B ２ O ３ On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of SiO ２ +B ２ O ３ The lower limit of the content is preferably 1% or more, 2% or more, 3% or more, and particularly preferably 5% or more.

[0047] Al ２ O ３is a component that contributes to the stability of vitrification, but if its content is too high, the refractive index tends to decrease. ２ O ３ The content of Al is preferably 0 to 5%. ２ O ３ The upper limit of the content of Al is preferably 5% or less, 3% or less, 2% or less, 1% or less, 0.2% or less, particularly preferably 0.1% or less. ２ O ３ The lower limit of the content of Al is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more.

[0048] Ga ２ O ３ is a component that forms a glass skeleton as an intermediate oxide and widens the vitrification range. It also has the effect of increasing the refractive index. ２ O ３ The content of is preferably 0 to 10%. ２ O ３ The lower limit of the content of is preferably 0% or more, 1% or more, particularly preferably 2% or more, and Ga ２ O ３ The upper limit of the content of Ga is preferably 10% or less, 7% or less, 6% or less, 5% or less, particularly preferably 4% or less. ２ O ３ If the content is too high, vitrification becomes difficult and the raw material cost tends to increase.

[0049] GeO ２ is a component that forms a glass skeleton as a glass network-forming component and expands the vitrification range. ２ The content of is preferably 0 to 10%. More specifically, GeO ２ The lower limit of the content of GeO is preferably 0% or more, 1% or more, particularly preferably 2% or more. ２ The upper limit of the content is preferably 10% or less, 7% or less, 6% or less, 5% or less, particularly preferably 4% or less. ２ If the content is too high, vitrification becomes difficult and the raw material cost tends to increase.

[0050] As component (As ２ O ３ etc.), Pb components (PbO etc.) and fluorine components (F ２ etc.) have a large environmental impact, and therefore it is preferable that they are not substantially contained.

[0051] Bi ２ O ３ and TeO ２ is a coloring component and tends to reduce the transmittance in the visible range. ２ O ３ The content of Bi is preferably 0 to 1%. ２ O ３ The upper limit of the content of TeO is 1% or less, 0.1% or less, or 0.01% or less, and it is particularly preferable that TeO is not substantially contained. ２ The content of TeO is preferably 0 to 1%. ２ The upper limit of the content is preferably 1% or less, 0.1% or less, or 0.01% or less, and it is particularly preferable that the content is substantially zero.

[0052] Fe ２ O ３ Pt and Rh are coloring components that tend to reduce the transmittance in the visible range, so their contents are preferably particularly small. ２ O ３ The content of is preferably less than 0.01%, less than 0.005%, less than 0.001%, less than 0.0005%, particularly preferably less than 0.0001%. ２ O ３ The lower limit of the Pt content is preferably 0.00001% or more. The Pt content is preferably 20 ppm or less, 10 ppm or less, particularly 5 ppm or less. The Rh content is preferably 1 ppm or less, 0.1 ppm or less, 0.01 ppm or less, particularly less than 0.01 ppm, and the lower limit of the Rh content is preferably 0.001 ppm or more. From the viewpoint of suppressing coloration, a lower Pt content is preferable, but to achieve this, the melting temperature must be lowered, which results in a decrease in solubility. Therefore, when solubility is taken into consideration, the lower limit of the Pt content is preferably 0.1 ppm or more, particularly 0.5 ppm or more.

[0053] The optical glass of the present invention contains clarifier components Cl and CeO ２ , S.O. ２ , Sb ２ O ３ or SnO ２ may be contained in an amount of 0 to 0.1% each.

[0054] From the viewpoint of increasing the refractive index, the mass ratio is ２ +Nb ２ O ５ ) / SiO ２ is preferably greater than 1, 2 or more, 2.5 or more, particularly 3.0 or more. ２ +Nb ２ O ５ ) / SiO ２ If "(TiO ２ +Nb ２ O ５ ) / SiO ２ " is TiO ２ +Nb ２ O ５ The content of (TiO ２ and Nb ２ O ５ (total amount of SiO ２ The value is calculated by dividing the content by the total amount of the compound.

[0055] TiO ２ -ZrO ２ From the viewpoint of suppressing the precipitation of TiO ２ / ZrO ２ is preferably 2 or more, 2.2 or more, 2.5 or more, 2.9 or more, particularly preferably 2.91 or more. From the viewpoint of enhancing the stability of vitrification, TiO ２ / ZrO ２ The upper limit may be 20 or less, 15 or less, and particularly 12 or less. ２ / ZrO ２ " is TiO ２ The content of ZrO ２ The value is calculated by dividing the content by the total amount of the compound.

[0056] From the viewpoint of increasing the refractive index, the mass ratio is (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) is preferably 1.000 or more, 1.500 or more, 2.000 or more, 3.500 or more, 3.800 or more, 4.000 or more, 4.300 or more, 4.500 or more, 4.800 or more, 5.100 or more, 5.200 or more, 5.400 or more, 5.500 or more, particularly preferably 5.600 or more. Furthermore, from the viewpoint of stabilizing vitrification while reducing density, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ The upper limit of "(La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) is La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The content of SiO ２ +B ２ O ３ The value is calculated by dividing the content by the total amount of the compound.

[0057] From the viewpoint of increasing the light transmittance in the visible range, HfO ２ / TiO ２ is preferably 0.02 or less, 0.01 or less, 0.009 or less, particularly preferably 0.005 or less, and HfO ２ / TiO ２ On the other hand, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance, HfO ２ / TiO ２ The lower limit of is preferably 0.001 or more, particularly preferably 0.002 or more. ２ / TiO ２ " is HfO ２ The content of TiO ２ The value is calculated by dividing the content by the total amount of the compound.

[0058] In order to increase the refractive index, the mass ratio is (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) is preferably 0.7 or less, 0.5 or less, particularly preferably 0.4 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ On the other hand, when emphasis is placed on reducing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The lower limit of "(MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O３ ")" is the content of MgO + CaO + SrO + BaO + ZnO in La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The value is calculated by dividing the content by the total amount of the compound.

[0059] In particular, from the viewpoint of increasing the Abbe number, the mass ratio is (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ ) is preferably 0.5 or less, 0.4 or less, 0.3 or less, particularly preferably 0.2 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ On the other hand, when emphasis is placed on reducing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ The lower limit of "(MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ ")" is the content of MgO + CaO + SrO + BaO + ZnO in La ２ O ３ + TiO ２ +Nb ２ O ５ The value is calculated by dividing the content by the total amount of the compound.

[0060] From the viewpoint of reducing density, the mass ratio is ZnO / Y ２ O ３ is preferably 50 or less, particularly preferably 40 or less, and ZnO / Y ２ O ３On the other hand, from the viewpoint of lowering the melting temperature, the lower limit of ZnO / Y ２ O ３ The lower limit of "ZnO / Y" may be 0.01 or more. ２ O ３ " represents the ZnO content as Y ２ O ３ The value is calculated by dividing the content by the total amount of the compound.

[0061] From the viewpoint of increasing the refractive index, in terms of mass ratio, B ２ O ３ / La ２ O ３ is preferably less than 1, 0.9 or less, 0.5 or less, particularly 0.10 or less, and B ２ O ３ / La ２ O ３ The lower limit of B is preferably 0 or more. ２ O ３ / La ２ O ３ The lower limit of B may be set to 0.01 or more. ２ O ３ / La ２ O ３ is B ２ O ３ The content of La ２ O ３ The value is calculated by dividing the content by the total amount of the compound.

[0062] From the viewpoint of increasing the refractive index, in terms of mass ratio, B ２ O ３ / SiO ２ is preferably 1 or less, 0.9 or less, particularly preferably 0.5 or less, and B ２ O ３ / SiO ２ The lower limit of B is preferably 0 or more. ２ O ３ / SiO ２ The lower limit of B may be set to 0.01 or more. ２ O ３ / SiO ２ is B ２ O ３ The content of SiO ２ The value is calculated by dividing the content by the total amount of the compound.

[0063] In view of the above, the preferred composition range of the optical glass A is, in mass %, SiO ２ 0-15%, TiO ２ 5-40%, La ２ O ３ 7.5-50%, Nb ２ O ５ 0-30%, Nb ２ O ５ +La ２ O ３ 7.5 to 80%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ It is preferable that the content of SiO is 1.5 or more, and ... ２ 0-12%, TiO ２ 10-35%, La ２ O ３ 14-48%, Nb ２ O ５ 1-20%, Nb ２ O ５ +La ２ O ３ 15 to 75%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ It is more preferable that the content is 1.5 or more, and in mass%, SiO ２ 0-12%, TiO ２ 14-35%, La ２ O ３ 20-45%, Nb ２ O ５ 1-20%, Nb ２ O ５ +La ２ O ３ 21 to 70%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ It is more preferable that the content is 1.5 or more, and in mass%, SiO ２ 0-12%, TiO ２ 16-35%, La ２ O３ 22-45%, Nb ２ O ５ 2-20%, Nb ２ O ５ +La ２ O ３ 24-60%, ZrO ２ 0-15%, HfO ２ 0 to 1%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ It is more preferable that the content is 1.5 or more, and in mass%, SiO ２ 1-12% TiO ２ 16-35%, La ２ O ３ 22-45%, Nb ２ O ５ 2-20%, Nb ２ O ５ +La ２ O ３ 24-60%, ZrO ２ 1-15%, HfO ２ 0.01 to 1%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ It is particularly preferable that the ratio is 1.5 or more.

[0064] By satisfying the above-mentioned requirements, the optical glass of this embodiment has a high Abbe number, excellent glass stability, and a low glass transition temperature. It also facilitates a reduction in density. Therefore, the optical glass of this embodiment achieves both a high refractive index and high light transmittance, and is also suitable for mass production.

[0065] <Optical Glass B> In one embodiment, the optical glass of the present invention contains, in mass %, SiO ２ 0-15%, TiO ２ 5 to less than 20%, La ２ O ３ 8-50%, Nb ２ O ５ 2-30%, Gd ２ O ３ 0-15%, BaO 0-less than 10%, B２ O ３ 0-0.1%, Al ２ O ３ 0-5%, MgO+CaO+SrO+BaO+ZnO 0-10%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) 3.500 or more (optical glass B). In the description of this embodiment, components that overlap with those of optical glass A may be omitted. Furthermore, components not described in the description of this embodiment may adopt the preferred components described in the description of optical glass A.

[0066] In this embodiment, SiO ２ More specifically, from the viewpoint of suppressing an increase in the melting temperature and a decrease in the internal transmittance, and suppressing a decrease in the refractive index, the content of SiO ２ The upper limit of the content of SiO is preferably 15% or less, 12% or less, particularly preferably 11% or less. ２ However, from the viewpoint of improving the stability of vitrification and decreasing the thermal expansion coefficient of glass, the lower limit of the content of SiO ２ The lower limit of the content is preferably 1% or more, 2% or more, 2.5% or more, 3% or more, 5% or more, and particularly preferably 6% or more.

[0067] In this embodiment, TiO ２ The content of TiO is preferably 5 to less than 20%, particularly preferably 5 to 19.9%. More specifically, from the viewpoint of increasing the refractive index of the glass and decreasing the density of the glass, ２The lower limit of the content of TiO is preferably 5% or more, 10% or more, 15% or more, particularly preferably 17% or more. ２ The upper limit of the content is preferably less than 20%, 19.9% ​​or less, 19.8% or less, 19.7% or less, particularly preferably 19.5% or less.

[0068] In this embodiment, La ２ O ３ The content of La is preferably 8 to 50%. More specifically, from the viewpoint of increasing the refractive index and improving the stability of vitrification, ２ O ３ The lower limit of the content of La is preferably 8% or more, 10% or more, 14% or more, 15% or more, 18% or more, 20% or more, 22% or more, 25% or more, 26% or more, particularly preferably 30% or more. ２ O ３ The upper limit of the content is preferably 50% or less, 48% or less, and particularly preferably 45% or less.

[0069] In this embodiment, Nb ２ O ５ The content of Nb is preferably 2 to 30%. ２ O ５ The lower limit of the content of Nb is preferably 2% or more, 3% or more, 4% or more, particularly preferably 5% or more. ２ O ５ The upper limit of the content is preferably 30% or less, 25% or less, 20% or less, 18% or less, particularly preferably 16% or less.

[0070] In this embodiment, ZrO ２ The content of ZrO is preferably 0 to 15%. ２ The upper limit of the content of ZrO is preferably 15% or less, 12% or less, 10% or less, particularly preferably 9% or less. ２ However, from the viewpoint of increasing the refractive index, the lower limit of the content of ZrO ２The lower limit of the content is preferably 1% or more, 2% or more, and particularly preferably 4% or more.

[0071] In this embodiment, Gd ２ O ３ More specifically, from the viewpoint of suppressing a decrease in mass productivity and suppressing an increase in density, the content of Gd ２ O ３ The upper limit of the content of is preferably 15% or less, particularly preferably 14% or less, and ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Gd ２ O ３ The lower limit of the content is preferably 0.1% or more, and particularly preferably 1% or more.

[0072] In this embodiment, Y ２ O ３ The content of Y is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in the melting temperature and stabilizing vitrification, ２ O ３ The upper limit of the content of Y is preferably 15% or less, 12% or less, 10% or less, 7% or less, particularly preferably 5% or less. ２ O ３ However, from the viewpoint of increasing the refractive index and chemical durability and further increasing the Young's modulus, the lower limit of the content of Y may be set to 0% or more. ２ O ３ The lower limit of the content is preferably 0.1% or more.

[0073] In this embodiment, Yb ２ O ３ The content of Yb is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in density of the glass and suppressing the occurrence of devitrification and striae, ２ O ３ The upper limit of the content of Yb is preferably 15% or less, 12% or less, 10% or less, particularly preferably 9% or less. ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Yb ２ O ３The lower limit of the content is preferably 0.1% or more, 1% or more, 2% or more, 2.5% or more, and particularly preferably 3% or more.

[0074] In this embodiment, WO ３ More specifically, from the viewpoint of increasing the light transmittance in the visible range and suppressing an increase in density, the content of WO ３ The upper limit of the content of WO is preferably 15% or less, 12% or less, particularly preferably 10% or less. ３ However, from the viewpoint of stabilizing vitrification, the lower limit of the content of WO ３ The lower limit of the content is preferably 0.1% or more.

[0075] In this embodiment, HfO ２ The content of HfO is preferably 0 to 1%. ２ The upper limit of the content of HfO is preferably 1% or less, 0.8% or less, 0.5% or less, 0.3% or less, particularly preferably 0.2% or less. ２ However, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance of the glass, the lower limit of the content of HfO ２ The lower limit of the content is preferably 0.01% or more, and particularly preferably 0.05% or more.

[0076] In this embodiment, the content of MgO + CaO + SrO is preferably 0 to 10%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the content of MgO + CaO + SrO is preferably 10% or less, 8% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of MgO + CaO + SrO is preferably 0% or more. However, from the viewpoint of stabilizing vitrification, the lower limit of the content of MgO + CaO + SrO may be 0.01% or more, and particularly 0.02% or more. The upper limit of the content of each of the components MgO, CaO, and SrO is preferably 10% or less, 8% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of each of the components MgO, CaO, and SrO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of each of MgO, CaO and SrO may be set to 0.01% or more, particularly 0.02% or more.

[0077] In this embodiment, the BaO content is preferably 0 to less than 10%. More specifically, from the viewpoint of stabilizing vitrification, the upper limit of the BaO content is preferably less than 10%, 8% or less, 5% or less, 4% or less, and particularly 3% or less, and the lower limit of the BaO content is preferably 0% or more. On the other hand, from the viewpoint of increasing the refractive index, the lower limit of the BaO content may be 0.1% or more.

[0078] In this embodiment, the ZnO content is preferably 0 to 10%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the ZnO content is preferably 10% or less, 9% or less, 8% or less, and particularly preferably 7% or less, and the lower limit of the ZnO content is preferably 0% or more. On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the ZnO content is preferably 0.1% or more.

[0079] In this embodiment, B ２ O ３ The content of B is preferably 0 to 0.1%. ２ O ３ The upper limit of the content of B is 0.1% or less, 0.05% or less, and it is particularly preferable that it is not substantially contained. ２O ３ The lower limit of the content may be 0% or more.

[0080] In this embodiment, Al ２ O ３ The content of Al is preferably 0 to 5%. More specifically, from the viewpoint of increasing the stability of vitrification and suppressing the decrease in the refractive index, ２ O ３ The upper limit of the content of Al is preferably 5% or less, 3% or less, 2% or less, or 1% or less, particularly preferably 0.1% or less. ２ O ３ On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the content of Al is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more.

[0081] In this embodiment, from the viewpoint of suppressing a decrease in light transmittance in the visible range, Fe ２ O ３ The content of is preferably less than 0.01%, less than 0.005%, less than 0.001%, less than 0.0005%, particularly preferably less than 0.0001%. ２ O ３ The lower limit of the Pt content is preferably 0.00001% or more. The Pt content is preferably 20 ppm or less, 10 ppm or less, particularly 5 ppm or less. The Rh content is preferably 1 ppm or less, 0.1 ppm or less, 0.01 ppm or less, particularly less than 0.01 ppm, and the lower limit of the Rh content is preferably 0.001 ppm or more. From the viewpoint of suppressing coloration, a lower Pt content is preferable, but to achieve this, the melting temperature must be lowered, which results in a decrease in solubility. Therefore, when solubility is taken into consideration, the lower limit of the Pt content is preferably 0.1 ppm or more, particularly 0.5 ppm or more.

[0082] In this embodiment, from the viewpoint of increasing the refractive index of the glass, Nb ２ O ５ +La ２ O ３The content of Nb is preferably 10% or more, 15% or more, 20% or more, 21% or more, 24% or more, 25% or more, 30% or more, 35% or more, particularly preferably 40% or more. ２ O ５ +La ２ O ３ If the content of Nb is too small, it becomes difficult to obtain the above effect. ２ O ５ +La ２ O ３ The upper limit of the content is preferably 80% or less, 75% or less, 70% or less, 65% or less, and particularly preferably 60% or less.

[0083] In this embodiment, from the viewpoint of increasing the refractive index of the glass and decreasing the density, TiO ２ +Nb ２ O ５ The content of TiO is preferably 7% or more, 10% or more, 15% or more, 20% or more, 21% or more, 24% or more, particularly preferably 25% or more. ２ +Nb ２ O ５ The upper limit of the content is preferably 60% or less, 50% or less, and particularly preferably 40% or less.

[0084] In this embodiment, from the viewpoint of enhancing the stability of vitrification, La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The content of La is preferably 8% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, particularly preferably 40% or more. ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The upper limit of the content is preferably 79.9% or less, 75% or less, 70% or less, 65% or less, 60% or less, and particularly preferably 55% or less.

[0085] In this embodiment, the content of MgO+CaO+SrO+BaO+ZnO is preferably 0 to 10%. More specifically, from the viewpoint of increasing the refractive index, the upper limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 10% or less, 9% or less, and particularly 8% or less, and the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification and reducing density, the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0.1% or more, and particularly 0.2% or more.

[0086] In this embodiment, Li ２ O + Na ２ O+K ２ The content of O is preferably 0 to 2%. More specifically, from the viewpoint of suppressing instability of vitrification and suppressing a decrease in the refractive index, Li ２ O + Na ２ O+K ２ The upper limit of the O content is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is substantially not contained. ２ O + Na ２ O+K ２ The lower limit of the O content is preferably 0% or more. ２ O + Na ２ O+K ２ The lower limit of the O content may be set to 0.01% or more. ２ O, Na ２ O and K ２ The upper limit of the content of each component of O is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is not substantially contained. ２ O, Na ２ O and K ２ The lower limit of the content of each component of O is preferably 0% or more. ２ O, Na ２ O and K ２ The lower limit of the content of each of the O components may be set to 0.01% or more.

[0087] In this embodiment, from the viewpoint of increasing the refractive index while suppressing a decrease in light transmittance in the visible range, SiO２ +B ２ O ３ The content of is preferably 0 to 15%. More specifically, SiO ２ +B ２ O ３ The upper limit of the content of SiO is preferably 15% or less, 10% or less, particularly preferably 9.4% or less. ２ +B ２ O ３ On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of SiO ２ +B ２ O ３ The lower limit of the content is preferably 1% or more, 2% or more, 3% or more, and particularly preferably 5% or more.

[0088] In this embodiment, from the viewpoint of obtaining a glass having a particularly high refractive index and stability, the mass ratio is ２ O ５ +La ２ O ３ ) / TiO ２ is preferably 2.0 or more, particularly 2.01 or more. ２ O ５ +La ２ O ３ ) / TiO ２ The upper limit is preferably 10 or less, 8 or less, 6 or less, and particularly preferably 3 or less.

[0089] In this embodiment, from the viewpoint of increasing the refractive index, the mass ratio of (TiO ２ +Nb ２ O ５ ) / SiO ２ is preferably 1 or more, 2 or more, 2.5 or more, particularly preferably 3.0 or more. ２ +Nb ２ O ５ ) / SiO ２ If is too large, the stability of vitrification tends to decrease and the light transmittance in the visible region tends to decrease, so the upper limit is preferably 10 or less, 8.0 or less, 6.1 or less, 4.0 or less, less than 3.7, particularly preferably 3.6 or less.

[0090] In this embodiment, TiO ２ -ZrO ２From the viewpoint of suppressing the precipitation of TiO ２ / ZrO ２ is preferably 2 or more, particularly 2.2 or more. From the viewpoint of enhancing the stability of vitrification, TiO ２ / ZrO ２ The upper limit may be 20 or less, 15 or less, and particularly 12 or less.

[0091] In this embodiment, in particular, from the viewpoint of increasing the refractive index, the mass ratio is (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) is preferably 3.500 or more, 3.800 or more, 4.000 or more, 4.300 or more, 4.500 or more, 4.800 or more, particularly preferably 5.100 or more. From the viewpoint of stabilizing vitrification and reducing density, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ The upper limit of ) is preferably 20,000 or less, 15,000 or less, 12,000 or less, 10,000 or less, 8,000 or less, particularly preferably 7,000 or less.

[0092] In this embodiment, from the viewpoint of increasing the light transmittance in the visible range, HfO ２ / TiO ２ is preferably 0.02 or less, 0.01 or less, 0.009 or less, particularly preferably 0.005 or less, and HfO ２ / TiO ２ On the other hand, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance, HfO ２ / TiO ２ The lower limit of is preferably 0.001 or more, particularly preferably 0.002 or more.

[0093] In this embodiment, from the viewpoint of increasing the refractive index, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) is preferably 0.7 or less, 0.5 or less, 0.4 or less, particularly preferably 0.2 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ On the other hand, when emphasis is placed on reducing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The lower limit of ) is preferably 0.001 or more.

[0094] In this embodiment, in particular, from the viewpoint of increasing the Abbe number, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ ) is preferably 0.5 or less, 0.4 or less, 0.3 or less, particularly preferably 0.2 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ On the other hand, from the viewpoint of decreasing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O５ The lower limit of ) is preferably 0.001 or more, particularly preferably 0.002 or more.

[0095] In this embodiment, in order to reduce the density, the mass ratio is ZnO / Y ２ O ３ The upper limit of ZnO / Y is preferably 50 or less, particularly preferably 40 or less. ２ O ３ On the other hand, from the viewpoint of reducing the melting temperature, the lower limit of ZnO / Y ２ O ３ The lower limit is preferably 0.01 or more.

[0096] In this embodiment, in terms of increasing the refractive index, B ２ O ３ / La ２ O ３ is preferably less than 1, 0.9 or less, 0.5 or less, particularly 0.10 or less, and B ２ O ３ / La ２ O ３ The lower limit of B is preferably 0 or more. ２ O ３ / La ２ O ３ The lower limit may be set to 0.01 or more.

[0097] In this embodiment, in terms of increasing the refractive index, B ２ O ３ / SiO ２ is preferably 1 or less, 0.9 or less, particularly preferably 0.5 or less, and B ２ O ３ / SiO ２ The lower limit of B is preferably 0 or more. ２ O ３ / SiO ２ The lower limit may be set to 0.01 or more.

[0098] In view of the above, the preferred composition range of the optical glass B is, in mass %, SiO ２ 1-15% TiO ２ 5 to less than 20%, La ２ O ３8-50%, Nb ２ O ５ 2-30%, Gd ２ O ３ 1-15%, BaO 0-less than 10%, B ２ O ３ 0-0.1%, Al ２ O ３ 0-5%, MgO+CaO+SrO+BaO+ZnO 0-10%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) It is preferable that the content is 3.500 or more, and in mass%, SiO ２ 2-15%, TiO ２ 10 to less than 20%, La ２ O ３ 18-48%, Nb ２ O ５ 2-30%, Gd ２ O ３ 1-15%, BaO 0-8%, B ２ O ３ 0-0.1%, Al ２ O ３ 0-3%, MgO+CaO+SrO+BaO+ZnO 0-9%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３) It is more preferable that the content is 3.500 or more, and in mass%, SiO ２ 2-15%, TiO ２ Less than 15-20%, La ２ O ３ 26-48%, Nb ２ O ５ 4-30%, Gd ２ O ３ 1-15%, BaO 0-8%, B ２ O ３ 0-0.1%, Al ２ O ３ 0-2%, MgO+CaO+SrO+BaO+ZnO 0-9%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) It is particularly preferable that the value is 3,500 or more.

[0099] The optical glass of this embodiment satisfies the above-mentioned requirements, which makes it easy to enhance the stability of the glass, and therefore the optical glass of this embodiment is preferable, particularly from the viewpoint of enhancing mass productivity.

[0100] <Optical Glass C> In one embodiment, the optical glass of the present invention contains, in mass %, SiO ２ 0-15%, TiO ２ 20-40%, La ２ O ３ 5-50%, B ２ O ３ 0-2.5%, Al ２ O ３ 0 to 3%, MgO+CaO+SrO+BaO+ZnO 0.1% or more, Li ２ O + Na ２ O+K ２ O 0 to 2%, and by mass ratio, (Nb ２O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, TiO ２ / ZrO ２ 2.9 or more, (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) 0.4 or less, B ２ O ３ / La ２ O ３ It is characterized in that the refractive index is 0.10 or less (optical glass C). In the description of this embodiment, description of configurations that overlap with those of optical glasses A and B may be omitted. Furthermore, configurations not described in the description of this embodiment may be equivalent to those of optical glasses A and B.

[0101] In this embodiment, SiO ２ More specifically, from the viewpoint of suppressing an increase in the melting temperature and a decrease in the internal transmittance, and suppressing a decrease in the refractive index, the content of SiO ２ The upper limit of the content of SiO is preferably 15% or less, 12% or less, particularly preferably 11% or less. ２ However, from the viewpoint of improving the stability of vitrification and decreasing the thermal expansion coefficient of glass, the lower limit of the content of SiO ２ The lower limit of the content is preferably 1% or more, 2% or more, 2.5% or more, 3% or more, and particularly preferably 6% or more.

[0102] In this embodiment, TiO ２ The content of TiO is preferably 20 to 40%. More specifically, from the viewpoint of increasing the refractive index of the glass and decreasing the density of the glass, ２ The lower limit of the content of TiO is preferably 20% or more, particularly preferably 20.01% or more. ２ The upper limit of the content is preferably 40% or less, 35% or less, and particularly preferably 30% or less.

[0103] In this embodiment, from the viewpoint of increasing the refractive index and improving the stability of vitrification, La ２ O ３ The content of La is preferably 5 to 50%. ２ O ３ The lower limit of the content of La is preferably 5% or more, 7.5% or more, 8% or more, 10% or more, 14% or more, 15% or more, 18% or more, 20% or more, 22% or more, 25% or more, 26% or more, 28% or more, particularly preferably 30% or more. ２ O ３ The upper limit of the content is preferably 50% or less, 48% or less, and particularly preferably 45% or less.

[0104] In this embodiment, Nb ２ O ５ The content of Nb is preferably 0 to 30%. ２ O ５ The lower limit of the content of Nb is preferably 0% or more, 2% or more, 3% or more, 4% or more, particularly preferably 5% or more. ２ O ５ The upper limit of the content is preferably 30% or less, 25% or less, 20% or less, 18% or less, particularly preferably 16% or less.

[0105] In this embodiment, ZrO ２ The content of ZrO is preferably 0 to 15%. ２ The upper limit of the content of ZrO is preferably 15% or less, 12% or less, 10% or less, 9% or less, particularly preferably 7% or less. ２ However, from the viewpoint of increasing the refractive index, the lower limit of the content of ZrO ２ The lower limit of the content is preferably 1% or more, and particularly preferably 2% or more.

[0106] In this embodiment, Gd ２ O ３ More specifically, from the viewpoint of suppressing a decrease in mass productivity and suppressing an increase in density, the content of Gd２ O ３ The upper limit of the content of Gd is preferably 20% or less, 15% or less, particularly preferably 14% or less. ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Gd ２ O ３ The lower limit of the content is preferably 0.1% or more, and particularly preferably 1% or more.

[0107] In this embodiment, Y ２ O ３ The content of Y is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in the melting temperature and stabilizing vitrification, ２ O ３ The upper limit of the content of Y is preferably 15% or less, 12% or less, 10% or less, 7% or less, particularly preferably 5% or less. ２ O ３ However, from the viewpoint of increasing the refractive index and chemical durability and further increasing the Young's modulus, the lower limit of the content of Y may be set to 0% or more. ２ O ３ The lower limit of the content is preferably 0.1% or more.

[0108] In this embodiment, Yb ２ O ３ The content of Yb is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in density of the glass and suppressing the occurrence of devitrification and striae, ２ O ３ The upper limit of the content of Yb is preferably 15% or less, 12% or less, 10% or less, 9% or less, 7% or less, 5% or less, 3% or less, particularly preferably 1% or less. ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Yb ２ O ３ The lower limit of the content is preferably 0.1% or more, 1% or more, 2% or more, 2.5% or more, and particularly preferably 3% or more.

[0109] In this embodiment, WO ３ More specifically, from the viewpoint of increasing the light transmittance in the visible range and suppressing an increase in density, the content of WO３ The upper limit of the content of WO is preferably 15% or less, 12% or less, 10% or less, 8% or less, particularly preferably 5% or less. ３ However, from the viewpoint of stabilizing vitrification, the lower limit of the content of WO ３ The lower limit of the content is preferably 0.1% or more.

[0110] In this embodiment, HfO ２ The content of HfO is preferably 0 to 1%. ２ The upper limit of the content of HfO is preferably 1% or less, 0.8% or less, 0.5% or less, 0.3% or less, particularly preferably 0.2% or less. ２ However, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance of the glass, the lower limit of the content of HfO ２ The lower limit of the content is preferably 0.01% or more, and particularly preferably 0.05% or more.

[0111] In this embodiment, the content of MgO + CaO + SrO is preferably 0 to 15%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the content of MgO + CaO + SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of MgO + CaO + SrO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of MgO + CaO + SrO may be 0.01% or more, and particularly 0.02% or more. The upper limit of the content of each of the components MgO, CaO, and SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of each of the components MgO, CaO, and SrO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of each of MgO, CaO and SrO may be set to 0.01% or more, particularly 0.02% or more.

[0112] In this embodiment, the BaO content is preferably 0 to 15%. More specifically, from the viewpoint of stabilizing vitrification, the upper limit of the BaO content is preferably 15% or less, 14% or less, 12% or less, and particularly preferably 11% or less, and the lower limit of the BaO content is preferably 0% or more. On the other hand, from the viewpoint of increasing the refractive index, the lower limit of the BaO content may be 0.1% or more.

[0113] In this embodiment, the ZnO content is preferably 0 to 15%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the ZnO content is preferably 15% or less, 12% or less, 10% or less, and particularly preferably 8% or less, and the lower limit of the ZnO content is preferably 0% or more. On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the ZnO content is preferably 0.1% or more.

[0114] In this embodiment, B ２ O ３ The content of B is preferably 0 to 2.5%. ２ O ３ The upper limit of the content of B is preferably 2.5% or less, 2% or less, 1.5% or less, 1% or less, particularly preferably 0.5% or less. ２ O ３ On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of B is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more, particularly 0.1% or more.

[0115] In this embodiment, Al ２ O ３ The content of Al is preferably 0 to 3%. More specifically, from the viewpoint of increasing the stability of vitrification and suppressing the decrease in the refractive index, ２ O ３ The upper limit of the content of Al is preferably 3% or less, 2% or less, 1% or less, particularly preferably 0.1% or less. ２ O ３ On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the content of Al is preferably 0% or more. ２ O ３The lower limit of the content may be set to 0.01% or more.

[0116] In this embodiment, from the viewpoint of suppressing a decrease in light transmittance in the visible range, Fe ２ O ３ The content of is preferably less than 0.01%, less than 0.005%, less than 0.001%, less than 0.0005%, particularly preferably less than 0.0001%. ２ O ３ The lower limit of the Pt content is preferably 0.00001% or more. Similarly, the Pt content is preferably 20 ppm or less, 10 ppm or less, particularly 5 ppm or less. Similarly, the Rh content is preferably 1 ppm or less, 0.1 ppm or less, 0.01 ppm or less, particularly less than 0.01 ppm, and the lower limit of the Rh content is preferably 0.001 ppm or more. From the viewpoint of suppressing coloration, a lower Pt content is preferable, but to do so, the melting temperature must be lowered, which results in a decrease in solubility. Therefore, when solubility is taken into consideration, the lower limit of the Pt content is preferably 0.1 ppm or more, particularly 0.5 ppm or more.

[0117] In this embodiment, from the viewpoint of increasing the refractive index of the glass, Nb ２ O ５ +La ２ O ３ The Nb content is preferably 30% or more, 35% or more, and particularly preferably 40% or more. ２ O ５ +La ２ O ３ If the content of Nb is too small, it becomes difficult to obtain the above effect. ２ O ５ +La ２ O ３ The upper limit of the content is preferably 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, and particularly preferably 50% or less.

[0118] In this embodiment, from the viewpoint of increasing the refractive index of the glass and decreasing the density, TiO ２ +Nb ２ O ５The content of TiO is preferably 20% or more, 21% or more, 24% or more, particularly preferably 25% or more. ２ +Nb ２ O ５ The upper limit of the content is preferably 60% or less, 50% or less, and particularly preferably 40% or less.

[0119] In this embodiment, from the viewpoint of enhancing the stability of vitrification, La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The content of La is preferably 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, and particularly preferably 35% or more. ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The upper limit of the content is preferably 79.9% or less, 75% or less, 70% or less, 65% or less, 60% or less, and particularly preferably 55% or less.

[0120] In this embodiment, the content of MgO+CaO+SrO+BaO+ZnO is preferably 0.1 to 15%. More specifically, from the viewpoint of stabilizing vitrification and reducing density, the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0.1% or more, 0.2% or more, 0.5% or more, 1% or more, and particularly 1.5% or more. On the other hand, from the viewpoint of increasing the refractive index, the upper limit of the content of MgO+CaO+SrO+BaO+ZnO may be 15% or less, and particularly 13% or less.

[0121] In this embodiment, Li ２ O + Na ２ O+K ２ The content of O is preferably 0 to 2%. More specifically, from the viewpoint of suppressing instability of vitrification and suppressing a decrease in the refractive index, Li ２ O + Na ２ O+K２ The upper limit of the O content is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is substantially not contained. ２ O + Na ２ O+K ２ The lower limit of the O content is preferably 0% or more. ２ O + Na ２ O+K ２ The lower limit of the O content may be set to 0.01% or more. ２ O, Na ２ O and K ２ The upper limit of the content of each component of O is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is not substantially contained. ２ O, Na ２ O and K ２ The lower limit of the content of each component of O is preferably 0% or more. ２ O, Na ２ O and K ２ The lower limit of the content of each of the O components may be set to 0.01% or more.

[0122] In this embodiment, from the viewpoint of increasing the refractive index while suppressing a decrease in light transmittance in the visible range, SiO ２ +B ２ O ３ The content of is preferably 0 to 15%. More specifically, SiO ２ +B ２ O ３ The upper limit of the content of SiO is preferably 15% or less, 10% or less, particularly preferably 9.4% or less. ２ +B ２ O ３ On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of SiO ２ +B ２ O ３ The lower limit of the content is preferably 1% or more, 2% or more, 3% or more, and particularly preferably 5% or more.

[0123] In this embodiment, from the viewpoint of obtaining a stable glass with a high refractive index, (Nb ２ O ５ +La ２ O ３ ) / TiO２ is preferably 1.5 or more, 1.51 or more, 1.55 or more, 1.6 or more, 1.65 or more, particularly preferably 1.70 or more. ２ O ５ +La ２ O ３ ) / TiO ２ The upper limit is preferably 10 or less, 8 or less, 6 or less, 3 or less, and particularly preferably 2.5 or less.

[0124] In this embodiment, from the viewpoint of increasing the refractive index, (TiO ２ +Nb ２ O ５ ) / SiO ２ is preferably 1 or more, 2 or more, 2.5 or more, 2.8 or more, particularly preferably 3.0 or more. ２ +Nb ２ O ５ ) / SiO ２ If is too large, the stability of vitrification tends to decrease and the light transmittance in the visible region tends to decrease, so the upper limit is preferably 10 or less, 8.0 or less, 6.1 or less, 4.0 or less, less than 3.7, particularly preferably 3.6 or less.

[0125] In this embodiment, TiO ２ -ZrO ２ From the viewpoint of suppressing the precipitation of TiO ２ / ZrO ２ is preferably 2.9 or more, particularly preferably 2.91 or more. From the viewpoint of enhancing the stability of vitrification, TiO ２ / ZrO ２ The upper limit may be 20 or less, 15 or less, and particularly 12 or less.

[0126] In this embodiment, from the viewpoint of increasing the refractive index, the mass ratio is (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３) is preferably 1.000 or more, 1.500 or more, 2.000 or more, 3.500 or more, 3.800 or more, 4.000 or more, 4.300 or more, 4.500 or more, 4.800 or more, particularly preferably 5.100 or more. From the viewpoint of stabilizing vitrification and reducing density, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ The upper limit of ) is preferably 20,000 or less, 15,000 or less, 12,000 or less, 10,000 or less, 8,000 or less, particularly preferably 7,000 or less.

[0127] In this embodiment, from the viewpoint of increasing the light transmittance in the visible range, HfO ２ / TiO ２ is preferably 0.02 or less, 0.01 or less, 0.009 or less, particularly preferably 0.005 or less, and HfO ２ / TiO ２ On the other hand, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance, HfO ２ / TiO ２ The lower limit of is preferably 0.001 or more, particularly preferably 0.002 or more.

[0128] In this embodiment, in particular, from the viewpoint of increasing the refractive index, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) is preferably 0.4 or less, 0.35 or less, particularly preferably 0.3 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O３ ) is preferably 0 or more. From the viewpoint of reducing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The lower limit of ) is preferably 0.01 or more, more preferably 0.05 or more, and particularly preferably 0.1 or more.

[0129] In this embodiment, in particular, from the viewpoint of increasing the Abbe number, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ ) is preferably 0.5 or less, 0.4 or less, 0.3 or less, particularly preferably 0.2 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ On the other hand, from the viewpoint of decreasing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ The lower limit of ) is preferably 0.001 or more, more preferably 0.01 or more, and even more preferably 0.02 or more.

[0130] In this embodiment, in order to reduce the density, the mass ratio is ZnO / Y ２ O ３ is preferably 50 or less, particularly preferably 40 or less, and ZnO / Y ２ O ３ On the other hand, from the viewpoint of lowering the melting temperature, the lower limit of ZnO / Y ２ O ３ The lower limit may be set to 0.01 or more.

[0131] In this embodiment, in particular, from the viewpoint of a high refractive index, B ２ O ３ / La ２ O ３ is preferably 0.10 or less, particularly preferably 0.05 or less, and B ２ O ３ / La ２ O ３ The lower limit of B is preferably 0 or more. ２ O ３ / La ２ O ３ The lower limit may be set to 0.01 or more.

[0132] In this embodiment, in terms of increasing the refractive index, B ２ O ３ / SiO ２ is preferably 1 or less, 0.9 or less, particularly preferably 0.5 or less, and B ２ O ３ / SiO ２ The lower limit of B is preferably 0 or more. ２ O ３ / SiO ２ The lower limit of may be set to 0.01 or more.

[0133] In view of the above, the preferred composition range of the optical glass C is, in mass %, SiO ２ 0-15%, TiO ２ 20-40%, La ２ O ３ 28-50%, Nb ２ O ５ 2-30%, B ２ O ３ 0-2.5%, Al ２ O ３ 0 to 3%, MgO+CaO+SrO+BaO+ZnO 0.1% or more, Li ２ O + Na ２ O+K ２ O 0 to 2%, and by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, TiO ２ / ZrO ２ 2.9 or more, (MgO + CaO + SrO + BaO + ZnO) / (La ２ O３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) 0.4 or less, B ２ O ３ / La ２ O ３ It is preferable that the content of SiO is 0.10 or less, and ... ２ 1-15% TiO ２ 20-40%, La ２ O ３ 28-50%, Nb ２ O ５ 2-30%, B ２ O ３ 0-2.5%, Al ２ O ３ 0 to 2%, MgO+CaO+SrO+BaO+ZnO 0.1% or more, Li ２ O + Na ２ O+K ２ O 0 to 2%, and by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, TiO ２ / ZrO ２ 2.9 or more, (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) 0.4 or less, B ２ O ３ / La ２ O ３ It is particularly preferable that the ratio is 0.10 or less.

[0134] The optical glass of this embodiment satisfies the above-mentioned requirements, making it easy to reduce the density, and therefore the optical glass of this embodiment is preferable from the perspective of reducing the weight of devices that use this optical glass.

[0135] <Optical Glass D> In one embodiment, the optical glass of the present invention contains SiO２ , TiO ２ , La ２ O ３ , Nb ２ O ５ and ZrO ２ as an essential component, and in mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ It is characterized in that the refractive index is 0.001 or more (optical glass D). In the description of this embodiment, description of configurations that overlap with those of optical glasses A to C may be omitted. Furthermore, configurations not described in the description of this embodiment may be equivalent to those of optical glasses A to C.

[0136] The optical glass of this embodiment is made of SiO ２ , TiO ２ , La ２ O ３ , Nb ２ O ５ and ZrO ２ More specifically, the optical glass of this embodiment contains SiO ２ More than 0% to 15%, TiO ２ 5-40%, La ２ O ３ 5-50%, Nb ２ O ５ 1 to 30% and ZrO ２ It is preferable that the content is 1 to 15%.

[0137] In this embodiment, SiO ２ The content of SiO is preferably more than 0% to 15%. More specifically, from the viewpoint of improving the stability of vitrification and reducing the thermal expansion coefficient of glass, ２ The lower limit of the content of SiO is preferably more than 0%, 1% or more, 2% or more, 2.5% or more, 3% or more, 4% or more, 5% or more, particularly preferably 6% or more. From the viewpoint of suppressing an increase in the melting temperature and a decrease in the light transmittance in the visible range, and suppressing a decrease in the refractive index, ２ The upper limit of the content is preferably 15% or less, 12% or less, and particularly preferably 11% or less.

[0138] In this embodiment, TiO ２ The content of TiO is preferably 5 to 40%. More specifically, from the viewpoint of increasing the refractive index and decreasing the density of the glass, ２ The lower limit of the content of TiO is preferably 5% or more, 5.5% or more, 10% or more, 14% or more, 15% or more, particularly preferably 16% or more. ２ The upper limit of the content of TiO is preferably 40% or less, 35% or less, and particularly preferably 30% or less. ２ The content of TiO is preferably 5 to less than 20%, particularly preferably 5 to 19.9%. ２ The content is preferably 20 to 40%, particularly preferably 23 to 40%.

[0139] In this embodiment, La ２ O ３ The content of La is preferably 5 to 50%. More specifically, from the viewpoint of increasing the refractive index and improving the stability of vitrification, ２ O ３ The lower limit of the content of La is preferably 5% or more, 7.5% or more, 8% or more, 10% or more, 14% or more, 15% or more, 18% or more, 20% or more, 22% or more, 25% or more, 26% or more, particularly preferably 30% or more. ２ O ３ The upper limit of the content is preferably 50% or less, 48% or less, and particularly preferably 45% or less.

[0140] In this embodiment, Nb ２ O ５ The content of Nb is preferably 1 to 30%. ２ O ５ The lower limit of the content of Nb is preferably 1% or more, 2% or more, 3% or more, 4% or more, particularly preferably 5% or more. ２ O ５The upper limit of the content is preferably 30% or less, 25% or less, 20% or less, 18% or less, particularly preferably 16% or less.

[0141] In this embodiment, ZrO ２ The content of ZrO is preferably 1 to 15%. ２ The lower limit of the content of ZrO is preferably 1% or more, 2% or more, particularly preferably 4% or more. ２ The upper limit of the content is preferably 15% or less, 12% or less, 10% or less, 9% or less, and particularly preferably 7% or less.

[0142] In this embodiment, Gd ２ O ３ More specifically, from the viewpoint of suppressing a decrease in mass productivity and suppressing an increase in density, the content of Gd ２ O ３ The upper limit of the content of is preferably 20% or less, 15% or less, 14% or less, 13% or less, 10% or less, 7% or less, particularly preferably 6% or less; ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Gd ２ O ３ The lower limit of the content is preferably 0.1% or more, 1% or more, and particularly preferably 2% or more.

[0143] In this embodiment, Y ２ O ３ The content of Y is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in the melting temperature and stabilizing vitrification, ２ O ３ The upper limit of the content of Y is preferably 15% or less, 12% or less, 10% or less, 7% or less, particularly preferably 5% or less. ２ O ３ However, from the viewpoint of increasing the refractive index and chemical durability and further increasing the Young's modulus, the lower limit of the content of Y may be set to 0% or more. ２ O ３ The lower limit of the content is preferably 0.1% or more, 1% or more, and particularly preferably 2% or more.

[0144] In this embodiment, Yb ２ O ３ The content of Yb is preferably 0 to 15%. More specifically, from the viewpoint of suppressing an increase in density of the glass and suppressing the occurrence of devitrification and striae, ２ O ３ The upper limit of the content of Yb is preferably 15% or less, 12% or less, 10% or less, 9% or less, particularly preferably 7% or less. ２ O ３ However, from the viewpoint of increasing the refractive index, the lower limit of the content of Yb ２ O ３ The lower limit of the content is preferably 0.1% or more, 1% or more, 2% or more, 2.5% or more, and particularly preferably 3% or more.

[0145] In this embodiment, WO ３ More specifically, from the viewpoint of increasing the light transmittance in the visible range and suppressing an increase in density, the content of WO ３ The upper limit of the content of WO is preferably 15% or less, 12% or less, 10% or less, 5% or less, less than 3%, 2% or less, particularly preferably 1% or less. ３ However, from the viewpoint of stabilizing vitrification, the lower limit of the content of WO ３ The lower limit of the content is preferably 0.1% or more.

[0146] In this embodiment, HfO ２ The content of HfO is preferably 0.01 to 1%. More specifically, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance of the glass, ２ The lower limit of the content of HfO is preferably 0.01% or more, particularly preferably 0.05% or more. ２ The upper limit of the content is preferably 1% or less, 0.8% or less, 0.5% or less, 0.3% or less, particularly preferably 0.2% or less.

[0147] In this embodiment, the content of MgO + CaO + SrO is preferably 0 to 15%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the content of MgO + CaO + SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of MgO + CaO + SrO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of MgO + CaO + SrO may be 0.01% or more, and particularly 0.02% or more. The upper limit of the content of each of the components MgO, CaO, and SrO is preferably 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and particularly 1% or less, and the lower limit of the content of each of the components MgO, CaO, and SrO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of each of MgO, CaO and SrO may be set to 0.01% or more, particularly 0.02% or more.

[0148] In this embodiment, the BaO content is preferably 0 to 15%. More specifically, from the viewpoint of stabilizing vitrification, the upper limit of the BaO content is preferably 15% or less, 14% or less, 12% or less, or 11% or less, particularly preferably less than 10%, and the lower limit of the BaO content is preferably 0% or more. On the other hand, from the viewpoint of increasing the refractive index, the lower limit of the BaO content may be 0.1% or more.

[0149] In this embodiment, the ZnO content is preferably 0 to 15%. More specifically, from the viewpoint of suppressing a decrease in the refractive index, the upper limit of the ZnO content is preferably 15% or less, 12% or less, 10% or less, and particularly preferably 8% or less, and the lower limit of the ZnO content is preferably 0% or more. On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the ZnO content is preferably 0.1% or more.

[0150] In this embodiment, B ２ O ３ The content of B is preferably 0 to 15%. ２ O ３The upper limit of the content of B is preferably 15% or less, 10% or less, 9% or less, 5% or less, 2.5% or less, 2% or less, 1.5% or less, 1% or less, particularly preferably 0.5% or less. ２ O ３ On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of B is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more, particularly 0.1% or more.

[0151] In this embodiment, Al ２ O ３ The content of Al is preferably 0 to 5%. More specifically, from the viewpoint of increasing the stability of vitrification and suppressing the decrease in the refractive index, ２ O ３ The upper limit of the content of Al is preferably 5% or less, 3% or less, 2% or less, or 1% or less, particularly preferably 0.1% or less. ２ O ３ On the other hand, from the viewpoint of improving the stability of vitrification, the lower limit of the content of Al is preferably 0% or more. ２ O ３ The lower limit of the content may be set to 0.01% or more.

[0152] In this embodiment, from the viewpoint of suppressing a decrease in light transmittance in the visible range, Fe ２ O ３ The content of is preferably less than 0.01%, less than 0.005%, less than 0.001%, less than 0.0005%, particularly preferably less than 0.0001%. ２ O ３ The lower limit of the Pt content is preferably 0.00001% or more. Similarly, the Pt content is preferably 20 ppm or less, 10 ppm or less, particularly 5 ppm or less. Similarly, the Rh content is preferably 1 ppm or less, 0.1 ppm or less, 0.01 ppm or less, particularly less than 0.01 ppm, and the lower limit of the Rh content is preferably 0.001 ppm or more. From the viewpoint of suppressing coloration, a lower Pt content is preferable, but to do so, the melting temperature must be lowered, which results in a decrease in solubility. Therefore, when solubility is taken into consideration, the lower limit of the Pt content is preferably 0.1 ppm or more, particularly 0.5 ppm or more.

[0153] In this embodiment, from the viewpoint of suppressing devitrification, Nb ２ O ５ +La ２ O ３ The Nb content is preferably 7.5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, and particularly preferably 40% or more. ２ O ５ +La ２ O ３ If the content of Nb is too small, it becomes difficult to obtain the above effect. ２ O ５ +La ２ O ３ The upper limit of the content is preferably 80% or less, 75% or less, 70% or less, 65% or less, and particularly preferably 60% or less.

[0154] In this embodiment, from the viewpoint of increasing the refractive index of the glass and decreasing the density, TiO ２ +Nb ２ O ５ The content of TiO is preferably 6% or more, 7.5% or more, 10% or more, 15% or more, 20% or more, 21% or more, 24% or more, and particularly preferably 25% or more. ２ +Nb ２ O ５ The upper limit of the content is preferably 60% or less, 50% or less, and particularly preferably 40% or less.

[0155] In this embodiment, from the viewpoint of enhancing the stability of vitrification, La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The content of La is preferably 5% or more, 8% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, particularly preferably 40% or more. ２ O ３ +Gd ２ O ３ +Y ２ O ３+Yb ２ O ３ The upper limit of the content is preferably 79.9% or less, 75% or less, 70% or less, 65% or less, 60% or less, and particularly preferably 55% or less.

[0156] In this embodiment, the content of MgO+CaO+SrO+BaO+ZnO is preferably 0 to 15%. More specifically, from the viewpoint of increasing the refractive index, the upper limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 15% or less, 12% or less, 10% or less, 9% or less, and particularly preferably 8% or less. The lower limit of the content of MgO+CaO+SrO+BaO+ZnO is preferably 0% or more. On the other hand, from the viewpoint of stabilizing vitrification and reducing density, the lower limit of the content of MgO+CaO+SrO+BaO+ZnO may be 0.1% or more, particularly preferably 0.2% or more.

[0157] In this embodiment, Li ２ O + Na ２ O+K ２ The content of O is preferably 0 to 2%. More specifically, from the viewpoint of suppressing instability of vitrification and suppressing a decrease in the refractive index, Li ２ O + Na ２ O+K ２ The upper limit of the O content is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is substantially not contained. ２ O + Na ２ O+K ２ The lower limit of the O content is preferably 0% or more. ２ O + Na ２ O+K ２ The lower limit of the O content may be set to 0.01% or more. ２ O, Na ２ O and K ２ The upper limit of the content of each component of O is 2% or less, 1% or less, or 0.5% or less, and it is particularly preferable that it is not substantially contained. ２ O, Na ２ O and K ２ The lower limit of the content of each component of O is preferably 0% or more. ２ O, Na ２O and K ２ The lower limit of the content of each of the O components may be set to 0.01% or more.

[0158] In this embodiment, from the viewpoint of increasing the refractive index while suppressing a decrease in light transmittance in the visible range, SiO ２ +B ２ O ３ The content of is preferably 0 to 15%. More specifically, SiO ２ +B ２ O ３ The upper limit of the content of SiO is preferably 15% or less, 10% or less, particularly preferably 9.4% or less. ２ +B ２ O ３ On the other hand, from the viewpoint of stabilizing vitrification, the lower limit of the content of SiO ２ +B ２ O ３ The lower limit of the content is preferably 1% or more, 2% or more, 3% or more, and particularly preferably 5% or more.

[0159] In this embodiment, from the viewpoint of obtaining a stable glass with a high refractive index, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ is preferably 1.5 or more, 1.51 or more, 1.55 or more, 1.6 or more, 1.65 or more, particularly preferably 1.70 or more. ２ O ５ +La ２ O ３ ) / TiO ２ The upper limit is preferably 10 or less, 8 or less, 6 or less, and particularly preferably 3 or less.

[0160] In this embodiment, from the viewpoint of increasing the refractive index, (TiO ２ +Nb ２ O ５ ) / SiO ２ is preferably 1 or more, 2 or more, 2.5 or more, particularly preferably 3.0 or more. ２ +Nb ２ O ５ ) / SiO ２If is too large, the stability of vitrification tends to decrease and the light transmittance in the visible region tends to decrease, so the upper limit is preferably 10 or less, 8.0 or less, 6.1 or less, 4.0 or less, less than 3.7, particularly preferably 3.6 or less.

[0161] TiO ２ -ZrO ２ From the viewpoint of suppressing the precipitation of TiO ２ / ZrO ２ is preferably 2 or more, 2.2 or more, 2.5 or more, 2.9 or more, particularly preferably 2.91 or more. From the viewpoint of enhancing the stability of vitrification, TiO ２ / ZrO ２ The upper limit may be 20 or less, 15 or less, and particularly 12 or less.

[0162] In this embodiment, from the viewpoint of increasing the refractive index, the mass ratio is (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) is preferably 1.000 or more, 1.500 or more, 2.000 or more, 3.500 or more, 3.800 or more, 4.000 or more, 4.300 or more, 4.500 or more, 4.800 or more, particularly preferably 5.100 or more. From the viewpoint of stabilizing vitrification and reducing density, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ The upper limit of ) is preferably 20,000 or less, 15,000 or less, 12,000 or less, 10,000 or less, 8,000 or less, particularly preferably 7,000 or less.

[0163] In this embodiment, from the viewpoint of increasing the crystallization temperature and improving the devitrification resistance, HfO ２ / TiO２ On the other hand, from the viewpoint of increasing the light transmittance in the visible range, HfO ２ / TiO ２ is preferably 0.02 or less, 0.01 or less, 0.009 or less, and particularly preferably 0.005 or less.

[0164] In this embodiment, from the viewpoint of increasing the refractive index, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) is preferably 0.7 or less, 0.5 or less, 0.4 or less, 0.35 or less, particularly preferably 0.3 or less. From the viewpoint of reducing density, (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ The lower limit of ) is preferably 0 or more, 0.001 or more, and particularly preferably 0.01 or more.

[0165] In this embodiment, in particular, from the viewpoint of increasing the Abbe number, the mass ratio is (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ ) is preferably 0.5 or less, 0.4 or less, 0.3 or less, particularly preferably 0.2 or less, and (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ On the other hand, from the viewpoint of decreasing the density, the lower limit of (MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５The lower limit of ) is preferably 0.001 or more, more preferably 0.01 or more, and even more preferably 0.02 or more.

[0166] In this embodiment, in order to reduce the density, the mass ratio is ZnO / Y ２ O ３ is preferably 50 or less, particularly preferably 40 or less, and ZnO / Y ２ O ３ On the other hand, from the viewpoint of lowering the melting temperature, the lower limit of ZnO / Y ２ O ３ The lower limit may be set to 0.01 or more.

[0167] In this embodiment, in terms of increasing the refractive index, B ２ O ３ / La ２ O ３ is preferably less than 1, 0.9 or less, 0.5 or less, particularly 0.10 or less, and particularly 0.05 or less; B ２ O ３ / La ２ O ３ The lower limit of B is preferably 0 or more. ２ O ３ / La ２ O ３ The lower limit may be set to 0.01 or more.

[0168] In this embodiment, in terms of increasing the refractive index, B ２ O ３ / SiO ２ is preferably 1 or less, 0.9 or less, particularly preferably 0.5 or less, and B ２ O ３ / SiO ２ The lower limit of B is preferably 0 or more. ２ O ３ / SiO ２ The lower limit may be set to 0.01 or more.

[0169] In view of the above, the preferred composition range of the optical glass D is, in mass %, SiO ２ More than 0% to 15%, TiO ２ 5-40%, La ２ O ３6.5-50%, Nb ２ O ５ 1 to 30% and ZrO ２ 1 to 15% by mass, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ It is preferable that the content of SiO is 0.001 or more, and ... ２ 1-15% TiO ２ 10-40%, La ２ O ３ 14-50%, Nb ２ O ５ 1 to 20% and ZrO ２ 1 to 15% by mass, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ It is more preferable that the content is 0.001 or more, and in mass%, SiO ２ 2-15%, TiO ２ 14-35%, La ２ O ３ 20-50%, Nb ２ O ５ 1 to 20% and ZrO ２ 1 to 15% by mass, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ It is particularly preferable that it is 0.001 or more.

[0170] By satisfying the above-mentioned constitution, the optical glass of this embodiment has excellent resistance to devitrification and can be made more suitable for mass production.

[0171] Preferred configurations other than the glass composition will be described below.

[0172] The optical glass of the present invention preferably has a refractive index (nd) of 2.03 or more, 2.040 or more, 2.050 or more, 2.070 or more, 2.080 or more, 2.090 or more, 2.095 or more, 2.100 or more, 2.101 or more, particularly 2.105 or more. If the refractive index (nd) is too low, the viewing angle tends to be narrow when used as a light guide plate for wearable image display devices such as projector-equipped glasses, eyeglass-type or goggle-type displays, virtual reality (VR) or augmented reality (AR) display devices, and virtual image display devices. On the other hand, if the refractive index (nd) is too high, defects such as devitrification and striae are likely to occur, so the upper limit of the refractive index (nd) is preferably 2.35 or less, 2.30 or less, particularly 2.20 or less.

[0173] In the optical glass of the present invention, from the viewpoint of increasing the refractive index of the glass, the upper limit of the Abbe number (νd) is preferably 30 or less, 28 or less, and particularly preferably 25 or less. On the other hand, from the viewpoint of increasing the stability of vitrification, the lower limit of the Abbe number (νd) is preferably 15 or more, 18 or more, 20 or more, and particularly preferably 21 or more.

[0174] The optical glass of the present invention has the above-mentioned constitution and therefore has high light transmittance in the visible range. Specifically, the internal transmittance τ at a wavelength of 450 nm at a thickness of 10 mm is ４５０ is preferably 70% or more, 75% or more, 80% or more, 85% or more, and particularly preferably 90% or more. In this way, in a wearable image display device using the optical glass of the present invention, the brightness of the image seen by the user tends to be increased.

[0175] The optical glass of the present invention preferably has a glass transition temperature (Tg) of 850°C or lower, 820°C or lower, and particularly preferably 800°C or lower. This allows the melting temperature to be lowered, making it possible to obtain a glass that has high transmittance and is suitable for mass production. There is no particular restriction on the lower limit of the glass transition temperature (Tg), but it may be, for example, 600°C or higher.

[0176] The optical glass of the present invention preferably has a crystallization temperature (Tc) of 800°C or higher, 850°C or higher, or 870°C or higher, particularly 900°C or higher. In this way, a glass with excellent mass productivity can be obtained. The lower limit of the crystallization temperature (Tc) is not particularly limited, but it may be, for example, 600°C or higher.

[0177] The optical glass of the present invention preferably has a difference between the glass transition temperature and the crystallization temperature (Tc - Tg) of 20°C or more, 50°C or more, 120°C or more, 150°C or more, and particularly 170°C or more. This makes it possible to obtain a glass that is less susceptible to devitrification during molding and has excellent mass productivity. There is no particular upper limit to (Tc - Tg), but it may be set to, for example, 500°C or less.

[0178] The optical glass of the present invention preferably has a liquidus temperature of 1350° C. or less, 1330° C. or less, and particularly preferably 1300° C. or less. ０．１ dPa·s or more, 10 ０．２ dPa·s or more, especially 10 ０．３ In this case, the glass is less likely to devitrify during melting or molding, which makes it easier to improve mass productivity.

[0179] The optical glass of the present invention has a density of 6.0 g / cm ３ Below, 5.5g / cm ３ Below, 5.3g / cm ３ Below, especially 5.0 g / cm ３ It is preferable that the density is 4 g / cm or less. Reducing the density of the optical glass can contribute to reducing the weight of the device. If the density is too high, the weight of the wearable device increases, which increases the discomfort when wearing the device. There is no particular lower limit for the density, but if it is too low, other properties such as optical properties tend to deteriorate, so it is preferable to set the density below 4 g / cm. ３ or more, especially 4.5 g / cm ３ It is preferable that this is equal to or greater than this.

[0180] The optical glass of the present invention has a thermal expansion coefficient of 95×10 at 30 to 380°C. －７ / ℃ or less, 90 x 10 －７ / °C or less, especially 85 x 10 －７ / °C or less. If the thermal expansion coefficient is too high, the glass is likely to break due to thermal shock. There is no particular lower limit for the thermal expansion coefficient, but if it is too low, other properties such as optical properties will deteriorate. －７ / °C or more, especially 75 x 10 －７ / ° C. or more. The thermal expansion coefficient refers to the average linear thermal expansion coefficient measured with a dilatometer.

[0181] The optical glass of the present invention is preferably in the form of a plate with a thickness of 1 mm or less. The upper limit of the thickness is preferably 1 mm or less, 0.8 mm or less, 0.6 mm or less, and particularly preferably 0.3 mm or less. If the thickness of the optical glass is too large, the weight of a wearable image display device using the optical glass increases, increasing discomfort when wearing the device. On the other hand, if the thickness of the optical glass is too small, the mechanical strength is likely to decrease. Therefore, the lower limit of the plate thickness is preferably 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, and particularly preferably 0.05 mm or more.

[0182] The optical glass of the present invention preferably has a planar shape that is circular, elliptical, or rectangular. In this case, the major axis (diameter in the case of a circle) of the main surface of the optical glass is preferably 100 mm or more, 120 mm or more, 150 mm or more, 160 mm or more, 170 mm or more, 180 mm or more, 190 mm or more, and particularly preferably 200 mm or more. If the major axis of the optical glass is too small, it becomes difficult to use it in applications such as wearable image display devices. In addition, mass productivity tends to be poor. There is no particular upper limit on the major axis of the optical glass, but in reality, it is preferably 1000 mm or less, particularly preferably 500 mm.

[0183] The optical glass of the present invention can be produced by melting raw materials prepared so as to obtain a predetermined glass composition, forming the molten glass, and then subjecting the molten glass to post-processing such as cutting and polishing as necessary.

[0184] The melting temperature of the optical glass is preferably 1500°C or lower, 1450°C or lower, 1400°C or lower, particularly preferably 1350°C or lower. If the melting temperature is too high, components of the melting container (Pt, Rh, etc.) tend to be easily eluted into the molten glass, and the optical transmittance of the resulting optical glass tends to decrease. On the other hand, if the melting temperature is low, bubbles and foreign matter (e.g., foreign matter derived from unmelted material) tend to be easily generated. Therefore, in order to reduce bubbles and foreign matter in the glass, the melting temperature is preferably 1200°C or higher, particularly preferably 1250°C or higher.

[0185] When producing the optical glass of the present invention, a gas can be bubbled into the melt for the purpose of clarifying the glass and improving its transmittance. ２ O, O ２ , N ２ The fining may be carried out under reduced pressure.

[0186] The optical glass of the present invention can be produced as glass cullet, and then reheated to obtain a homogeneous optical glass. When reheating, a different type of glass may be added in addition to the cullet. In addition to a platinum crucible, a platinum-rhodium crucible, a quartz crucible, an aluminum nitride crucible, a boron nitride crucible, a zirconia crucible, a silicon carbide crucible, a molybdenum crucible, a tungsten crucible, and the like can be used to produce the cullet.

[0187] The optical glass of the present invention can be suitably used for optical elements. It is particularly suitable for use as a light guide plate, which is a plate-shaped light guide element. For example, it can be suitably used as a light guide plate, which is a component of a wearable image display device selected from projector-equipped glasses, eyeglass-type or goggle-type displays, virtual reality or augmented reality display devices, and virtual image display devices. The light guide plate is used in the so-called eyeglass lens portion of the wearable image display device, and serves to guide light emitted from an image display element provided in the wearable image display device and emit it toward the user's pupil. The surface of the light guide plate is preferably provided with a diffraction grating for diffracting light emitted from the image display element inside the light guide plate. The optical glass of the present invention may also be used in optical elements other than light guide plates, such as light guide elements, lenses, and prisms.

[0188] The optical glass of the present invention may be used as a supporting glass substrate for supporting a processed substrate. For example, it can be used as a supporting glass substrate for supporting a semiconductor. For example, the optical glass of the present invention can be used as a supporting glass substrate used to support a processed substrate on which a semiconductor chip is molded in a resin in the manufacturing process of a semiconductor package. This is preferable.

[0189] The supporting glass substrate is preferably in the form of a wafer, and its diameter is preferably 100 mm or more and 500 mm or less, particularly 150 mm or more and 450 mm or less. This makes it easy to apply to the manufacturing process of fan-out type WLP. If necessary, it may be processed into other shapes, such as a rectangular shape.

[0190] The supporting glass substrate preferably has a notch portion (notch-shaped alignment portion). Furthermore, the deep portion of the notch portion is more preferably substantially circular or substantially V-groove-shaped in plan view. This makes it easier to fix the position of the supporting glass substrate by abutting a positioning member such as a positioning pin against the notch portion of the supporting glass substrate. As a result, alignment of the supporting glass substrate and the processing substrate becomes easier. In particular, forming a notch portion in the processing substrate and abutting a positioning member thereon facilitates alignment of the entire laminate.

[0191] The circularity of the supporting glass substrate is preferably 1 mm or less, 0.1 mm or less, 0.05 mm or less, and particularly preferably 0.03 mm or less. The smaller the circularity, the easier it is to apply to the manufacturing process of fan-out type WLP. Note that "circularity" is the value obtained by subtracting the minimum value from the maximum value of the outer shape of the wafer, excluding the notch portion.

[0192] The total thickness variation (TTV) of the supporting glass substrate is preferably 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less, particularly 0.1 to less than 1 μm. The arithmetic mean roughness Ra is preferably 20 nm or less, 10 nm or less, 5 nm or less, 2 nm or less, or 1 nm or less, particularly 0.5 nm or less. The higher the surface precision, the easier it is to improve the processing precision. In particular, wiring precision can be improved, enabling high-density wiring. In addition, the strength of the supporting glass substrate is improved, making the supporting glass substrate and laminate less susceptible to breakage. Furthermore, the number of times the supporting glass substrate can be reused can be increased. The "arithmetic mean roughness Ra" can be measured using a stylus surface roughness meter or an atomic force microscope (AFM).

[0193] The present invention will be explained in detail below using examples, but the present invention is not limited to these examples.

[0194] Tables 1 to 8 show Examples 1 to 74 of the present invention and Comparative Examples 1 and 2. In the tables, "RO" means "MgO + CaO + SrO + BaO + ZnO." ２ O ３ " is "La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ " in the table. ２ O ３ / (SiO ２ +B ２ O ３ ) is "(La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ "RO / Ln" in the table means ２ O ３ ” is “(MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ +Gd ２ O３ +Y ２ O ３ +Yb ２ O ３ "RO / (La)" in the table means ２ O ３ + TiO ２ +Nb ２ O ５ )” is “(MgO+CaO+SrO+BaO+ZnO) / (La ２ O ３ + TiO ２ +Nb ２ O ５ )"

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203] The samples were prepared as follows. First, glass raw materials were melted in a platinum crucible at 1350 to 1500°C for 2 hours. The molten glass was then poured onto a carbon plate and annealed for 2 to 48 hours to obtain samples. The compositions of the obtained samples were analyzed using an XRF analyzer (ZSX Primus IV manufactured by RIGAKU). The results are shown in Tables 1 to 8.

[0204] The refractive index (nd), Abbe number (νd), internal transmittance (τ450), glass transition temperature (Tg), crystallization temperature (Tc), density, and thermal expansion coefficient α ３０－３８０ The results are shown in Tables 1 to 8.

[0205] The refractive index (nd) was measured using a Kalnew precision refractometer (Shimadzu Corporation, KPR-2000) to determine the refractive index for the d line (587.6 nm) of a helium lamp.

[0206] The Abbe number (νd) was calculated from the formula νd=[(nd−1) / (nF−nC)] using the refractive index for the d line, the F line (486.1 nm) of a hydrogen lamp, and the C line (656.3 nm) of a hydrogen lamp.

[0207] The internal transmittance (τ450) was measured as follows. Optically polished samples with a thickness of 10 mm ± 0.1 mm and a thickness of 3 mm ± 0.1 mm were prepared, and the light transmittance (linear transmittance) including surface reflection loss was measured at 1 nm intervals using a spectrophotometer (Shimadzu UV-3100). The internal transmittance curve for the 10 mm thickness was determined from the light transmittance data for each thickness sample, and the internal transmittance at a wavelength of 450 nm was read.

[0208] The glass transition temperature (Tg) and crystallization temperature (Tc) were measured using 0.3 to 0.6 g of glass powder crushed to 100 μm or less using a differential scanning calorimeter (manufactured by TA Instruments, product number "DSC2500") at temperatures between 25°C and 1200°C, at a temperature increase / decrease rate of 10°C / min.

[0209] The density was measured by the Archimedes method using a glass sample weighing about 10 g.

[0210] Thermal expansion coefficient α ３０－３８０ is the average coefficient of linear thermal expansion measured with a dilatometer.

[0211] As shown in Tables 1 to 8, the samples of Examples 1 to 74 had a refractive index of 2.03 or more and an Abbe number of 20 to 30. On the other hand, the glasses of Comparative Examples 1 and 2 were devitrified.

[0212] The optical glass of the present invention can be suitably used for optical elements, particularly as a light guide plate for use in a wearable image display device selected from eyeglasses with a projector, eyeglass-type or goggle-type displays, virtual reality or augmented reality display devices, and virtual image display devices.

Claims

1. SiO ２ 0-15%, TiO ２ 5-40%, La ２ O ３ Contains 5 to 50% by mass, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, and a refractive index nd of 2.03 or more.

2. SiO ２ 0-15%, TiO ２ 5-20% or less, La ２ O ３ 8-50%, Nb ２ O ５ 2-30%, Gd ２ O ３ 0-15%, BaO 0-10%, B ２ O ３ 0-0.1%, Al ２ O ３ 0-5%, MgO+CaO+SrO+BaO+ZnO 0-10%, and (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 2.0 or more, (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) / (SiO ２ +B ２ O ３ ) 3.500 or more.

3. SiO ２ 0-15%, TiO ２ 20-40%, La ２ O ３ 5-50%, B ２ O ３ 0-2.5%, Al ２ O ３ 0 to 3%, MgO+CaO+SrO+BaO+ZnO 0.1% or more, Li ２ O+Na ２ O+K ２ O 0 to 2%, by mass ratio, (Nb ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, TiO ２ / ZrO ２ 2.9 or more, (MgO + CaO + SrO + BaO + ZnO) / (La ２ O ３ +Gd ２ O ３ +Y ２ O ３ +Yb ２ O ３ ) 0.4 or less, B ２ O ３ / La ２ O ３ Optical glass having a refractive index of 0.10 or less.

4. SiO ２ , TiO ２ , La ２ O ３ , Nb ２ O ５ and ZrO ２ As an essential component, the mass ratio is ２ O ５ +La ２ O ３ ) / TiO ２ 1.5 or more, HfO ２ / TiO ２ 0.001 or more.

5. Furthermore, by mass ratio, HfO ２ / TiO ２ The optical glass according to any one of claims 1 to 3, wherein the refractive index is 0.001 or more.

6. The optical glass according to any one of claims 1 to 4, which has an Abbe number vd of 30 or less.

7. Internal transmittance τ at a wavelength of 450 nm with a thickness of 10 mm ４５０ The optical glass according to any one of claims 1 to 4, wherein the ratio of the refractive index to the refractive index of the optical glass is 70% or more.

8. Density is 6.0 g / cm ３ 5. The optical glass according to claim 1, wherein:

9. The optical glass according to any one of claims 1 to 4, which is in the form of a plate having a thickness of 1 mm or less.

10. The optical glass according to claim 9, wherein the major axis of the principal surface is 100 mm or more.

11. An optical element comprising the optical glass according to any one of claims 1 to 4.

12. A light guide plate comprising the optical glass according to any one of claims 1 to 4.

13. The light guide plate according to claim 12, which is used in a wearable image display device selected from glasses with a projector, an eyeglass-type or goggle-type display, a virtual reality or augmented reality display device, and a virtual image display device.

14. A wearable image display device comprising the light guide plate according to claim 12.