Glass and method for manufacturing glass

Abstract

The present invention suppresses the precipitation of defects while achieving a high refractive index and high transmittance. The glass (10) contains La2O3 and B2O3, has a refractive index (nd) of 2.0100 or more, has a total content of Bi2O3 and B2O3 of less than 80% in terms of mol% on the basis of oxides, has a total content of Pt and Fe in terms of mass ratio of 0.5-15.0 ppm, and has a parameter (A) defined by formula (1) of 0.870 or more.

Description

Technical Field

[0001] This invention relates to glass and a method for manufacturing glass. Background Technology

[0002] In recent years, there has been a search for glass with high refractive index. Especially in wearable devices such as head-mounted displays that realize AR (Augmented Reality), VR (Virtual Reality), and MR (Mixed Reality), high refractive index for visible light is required as a light guide plate. For example, Patent Document 1 describes optical glass with a refractive index of 1.64 to 1.85.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2018 / 235725 Summary of the Invention

[0006] However, high-refractive-index glasses tend to have lower transmittance. Furthermore, high-refractive-index glasses are more prone to the precipitation of impurities and other defects. Therefore, it is necessary to achieve both high refractive index and high transmittance while suppressing defect precipitation.

[0007] The purpose of this invention is to provide a glass and a method for manufacturing the glass that can suppress defect precipitation while achieving high refractive index and high transmittance.

[0008] The glass disclosed herein comprises La2O3 and B2O3, with a refractive index n d The total content of Bi2O3 and B2O3 is less than 80% in mol% based on oxides, and the total content of Pt and Fe is 0.5ppm to 15.0ppm by mass. The parameter A shown in formula (1) is 0.870 or more.

[0009] A = τ 440 +0.005×(Pt+Fe)···(1)

[0010] The glass manufacturing method disclosed herein includes: heating a raw material at 950°C to 1600°C to melt the raw material; and cooling the melted raw material to obtain the glass.

[0011] According to the present invention, it is possible to suppress the precipitation of defects while achieving both high refractive index and high transmittance. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the glass in this embodiment.

[0013] Figure 2 This is a cross-sectional view of the glass in this embodiment when it is made into a glass plate. Detailed Implementation

[0014] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and in the case of multiple embodiments, it includes technical solutions formed by combining various embodiments. Furthermore, numerical values ​​include a range of rounding. Additionally, the numerical range indicated by "~" refers to the range of values ​​before and after "~" as both the lower and upper limits; the same meaning will be used in the following context. Furthermore, in this embodiment, the lower and upper limits can be appropriately combined.

[0015] (Glass)

[0016] Figure 1 This is a schematic diagram of the glass in this embodiment. (As shown) Figure 1 As shown, the glass 10 in this embodiment is a plate-shaped glass plate, but the shape of the glass 10 is not limited to a plate shape and can be arbitrary. In this embodiment, the glass 10 is used as a light guide plate. More specifically, the glass 10 is used as a light guide plate for a head-mounted display. A head-mounted display refers to a display device (wearable device) worn on a person's head. However, the use of the glass 10 is arbitrary and is not limited to being used as a light guide plate, nor is it limited to being used in a head-mounted display.

[0017] (Refractive index n) d )

[0018] The refractive index n of glass 10 d The refractive index n is 2.0100 or higher, preferably 2.0150 or higher, more preferably 2.0200 or higher, more preferably 2.0250 or higher, more preferably 2.0300 or higher, more preferably 2.0350 or higher, and more preferably 2.0400 or higher. Furthermore, the refractive index n of glass 10... d Preferably, the refractive index n is 2.2000 or less, more preferably 2.1800 or less, more preferably 2.1600 or less, more preferably 2.1400 or less, more preferably 2.1200 or less, more preferably 2.1100 or less, and more preferably 2.0600 or less. Furthermore, the refractive index n of glass 10... d Preferably, the refractive index is 2.0150–2.2000, more preferably 2.0200–2.1800, even more preferably 2.0250–2.1600, even more preferably 2.0300–2.1400, even more preferably 2.0350–2.1200, and even more preferably 2.0400–2.0600. This is achieved by making the refractive index n… dWithin this range, the high refractive index relative to visible light enables the glass 10 to acquire appropriate optical properties.

[0019] It should be noted that the refractive index n d This refers to the refractive index of helium at the d-line (wavelength 587.6 nm). Refractive index n d It can be determined using the V-block method.

[0020] (Parameter A)

[0021] The parameter A of glass 10 is shown in equation (1).

[0022] A = τ 440 +0.005×(Pt+Fe)···(1)

[0023] τ in equation (1) 440 This is the internal transmittance to light with a wavelength of 440 nm when the thickness is 10 mm. Additionally, (Pt + Fe) is the ratio (ppm) of the total content of Pt and Fe relative to the total volume of glass 10, expressed as a mass ratio.

[0024] The parameter A specified by formula (1) is a value of 0.870 or higher. Parameter A is preferably 0.880 or higher, more preferably 0.890 or higher, more preferably 0.900 or higher, more preferably 0.910 or higher, more preferably 0.920 or higher, and more preferably 0.930 or higher, thereby taking into account both the internal transmittance of the glass and appropriate manufacturing conditions, and is therefore preferred.

[0025] Glass 10 maintains a high transmittance of visible light even when Pt and Fe are included, by setting parameter A, which specifies the relationship between the total content of Pt and Fe and the transmittance, to the range described above.

[0026] It should be noted that internal transmittance is the transmittance through the interior of glass 10. Internal transmittance can be calculated using the measured values ​​of two external transmittances with different plate thicknesses and the following formula (A). It should be noted that external transmittance refers to transmittance including surface reflection loss. In formula (A), τ is the internal transmittance of the glass converted to a thickness of 10 mm, T1 and T2 are the external transmittances, and Δd is the difference in sample thickness. External transmittance can be measured using a spectrophotometer (Hitachi High-Tech Co., Ltd.: U-4100) on a sample with double-sided mirror polished to a plate thickness of 10 mm.

[0027]

[0028] Furthermore, the Pt and Fe here do not refer only to the elemental Pt and Fe contained in glass 10, but can include elemental Pt and Fe as well as compounds. That is, the total Pt and Fe content can be said to refer to the content of elemental Pt and Fe as well as the content of Pt and Fe ions in the compounds.

[0029] The contents of Pt and Fe can be determined by ICP mass spectrometry. For example, an Agilent 8800 from Agilent Technologies can be used as the measuring instrument. Follow the steps below for determination.

[0030] In determining the content, a mixture of hydrofluoric acid and sulfuric acid is added to the crushed glass 10, and the mixture is heated to decompose it. After decomposition, hydrochloric acid is added to bring the volume to a certain level, and the concentration of the element to be measured is determined by ICP mass spectrometry. The concentration is calculated using a calibration curve prepared using standard solutions. Based on the measured concentration and the amount of glass 10 decomposed, the concentration of the element to be measured in glass 10 can be calculated. The following elements can also be determined using the same procedure.

[0031] (Parameter B)

[0032] The parameter B of glass 10 is shown in equation (2).

[0033] B = τ 460 +0.583×n d ···(2)

[0034] Where, τ 460 To convert the internal transmittance to light with a wavelength of 460nm for a thickness of 10mm, n d The refractive index n of glass 10 d .

[0035] In formula (2), parameter B is a value of 2.075 or higher. Parameter B is preferably 2.080 or higher, more preferably 2.090 or higher, more preferably 2.100 or higher, more preferably 2.105 or higher, more preferably 2.112 or higher, more preferably 2.115 or higher, more preferably 2.117 or higher, more preferably 2.118 or higher, more preferably 2.124 or higher, more preferably 2.127 or higher, and more preferably 2.130 or higher. This results in a high-viewing-angle and clear image, and is therefore preferred.

[0036] By setting the parameter B, which represents the relationship between refractive index and transmittance, to the range described above, glass 10 can maintain a high transmittance of visible light even with a high refractive index.

[0037] (composition)

[0038] The composition of glass 10 will be described below.

[0039] (La2O3 and B2O3)

[0040] Glass 10 contains La2O3 and B2O3. By including La2O3 and B2O3, it is possible to achieve a suitable high refractive index and high transmittance.

[0041] The presence of La2O3 and B2O3 can be determined by ICP mass spectrometry. For example, the Agilent 8800 from Agilent Technologies can be used as the measuring instrument.

[0042] (Pt and Fe)

[0043] In glass 10, the total content of Pt and Fe relative to the total content of glass 10 by mass ratio is 0.5 ppm to 15.0 ppm, preferably 1.0 ppm or more, more preferably 2.0 ppm or more, more preferably 3.0 ppm or more, more preferably 4.0 ppm or more, more preferably 5.0 ppm or more, and more preferably 6.0 ppm or more. In glass 10, the total content of Pt and Fe relative to the total content of glass 10 by mass ratio is preferably 14.0 ppm or less, more preferably 13.0 ppm or less, more preferably 12.0 ppm or less, more preferably 11.0 ppm or less, more preferably 10.0 ppm or less, and more preferably 9.0 ppm or less. In glass 10, the total content of Pt and Fe relative to the total content of glass 10 by mass ratio is preferably 1.0 ppm to 14.0 ppm, more preferably 2.0 ppm to 13.0 ppm, more preferably 3.0 ppm to 12.0 ppm, more preferably 4.0 ppm to 11.0 ppm, more preferably 5.0 ppm to 10.0 ppm, and more preferably 6.0 ppm to 9.0 ppm. By setting the upper limit of Pt and Fe to this range, the precipitation of Pt and Fe as defects can be suppressed. In addition, by setting the lower limit of Pt and Fe to this range, materials containing Pt and Fe can be used in raw materials, crucibles, and other equipment during manufacturing, thereby enabling appropriate manufacturing.

[0044] (Bi2O3 and B2O3)

[0045] In glass 10, the total content of Bi₂O₃ and B₂O₃, expressed as mole % based on oxides, is less than 80.0%, preferably 75.0% or less, more preferably 70.0% or less, more preferably 65.0% or less, more preferably 60.0% or less, more preferably 55.0% or less, more preferably 50.0% or less, and even more preferably 45.0% or less. In glass 10, the total content of Bi₂O₃ and B₂O₃, expressed as mole % based on oxides, is preferably 0% or more, more preferably 1.5% or more, more preferably 5.0% or more, more preferably 10.0% or more, more preferably 15.0% or more, more preferably 20.0% or more, and even more preferably 25.0% or more. In glass 10, the total content of Bi2O3 and B2O3, expressed as mole percent based on oxides, is preferably 0% to 75.0%, preferably 1.5% to 70.0%, preferably 5.0% to 65.0%, preferably 10.0% to 60.0%, preferably 15.0% to 55.0%, preferably 20.0% to 50.0%, and more preferably 25.0% to 45.0%. By setting the total content of Bi2O3 and B2O3 within this range, high refractive index and high transmittance can be appropriately achieved.

[0046] (Preferred composition)

[0047] The preferred composition of the glass 10 will be described in detail below.

[0048] (SiO2)

[0049] Glass 10 preferably contains SiO2. In glass 10, the SiO2 content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.0% or more, more preferably 2.0% or more, more preferably 3.0% or more, more preferably 4.0% or more, more preferably 5.0% or more, more preferably 6.0% or more, and even more preferably 7.0% or more. In glass 10, the SiO2 content, expressed as a mole % based on oxides, is preferably 20.0% or less, more preferably 19.0% or less, more preferably 18.0% or less, more preferably 17.0% or less, more preferably 16.0% or less, more preferably 15.0% or less, more preferably 14.0% or less, preferably 13.0% or less, and even more preferably 10.0% or less. In glass 10, the SiO2 content, expressed as a mole percent based on oxides, is preferably 0% to 20.0%, more preferably 1.0% to 19.0%, even more preferably 2.0% to 18.0%, even more preferably 3.0% to 17.0%, even more preferably 4.0% to 16.0%, even more preferably 5.0% to 15.0%, even more preferably 6.0% to 14.0%, preferably 7.0% to 13.0%, and even more preferably 7.0% to 10.0%. By setting the SiO2 content within this range, the coloration of the glass is reduced, the transmittance to short-wavelength visible light is increased, and stable glass formation is promoted, thereby improving the glass's resistance to devitrification.

[0050] (B2O3)

[0051] Glass 10 preferably contains B2O3. In glass 10, the content of B2O3, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.5% or more, more preferably 3.5% or more, more preferably 5.0% or more, more preferably 7.5% or more, more preferably 10.0% or more, more preferably 12.0% or more, more preferably 13.0% or more, more preferably 14.0% or more, more preferably 15.0% or more, and even more preferably 16.0% or more. In glass 10, the content of B2O3, expressed as a mole % based on oxides, is preferably 30.0% or less, more preferably 28.0% or less, more preferably 26.0% or less, more preferably 24.0% or less, more preferably 22.0% or less, more preferably 21.0% or less, more preferably 20.0% or less, and even more preferably 19.5% or less. In glass 10, the content of B2O3, expressed as mole percent based on oxides, is preferably 0% to 30.0%, more preferably 1.5% to 28.0%, more preferably 3.5% to 26.0%, more preferably 5.0% to 24.0%, more preferably 7.5% to 22.0%, more preferably 10% to 21.0%, more preferably 12% to 20.0%, more preferably 14% to 20.0%, and even more preferably 16% to 19.5%. By setting the B2O3 content within this range, the coloration of the glass is reduced, the transmittance to short-wavelength visible light is increased, and stable glass formation is promoted, thereby improving the glass's resistance to devitrification.

[0052] (Y2O3)

[0053] Glass 10 preferably contains Y₂O₃. In glass 10, the content of Y₂O₃, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.5% or more, more preferably 1.0% or more, more preferably 1.5% or more, more preferably 2.0% or more, and even more preferably 2.5% or more. In glass 10, the content of Y₂O₃, expressed as a mole % based on oxides, is preferably 10.0% or less, more preferably 8.0% or less, more preferably 6.0% or less, more preferably 5.0% or less, more preferably 4.5% or less, preferably 4.0% or less, and even more preferably 3.0% or less. In glass 10, the content of Y₂O₃, expressed as a mole % based on oxides, is preferably 0% to 10.0%, more preferably 0.5% to 8.0%, more preferably 1.0% to 6.0%, more preferably 1.5% to 5.0%, more preferably 2.0% to 4.5%, and even more preferably 2.5% to 4.0%, and even more preferably 2.5% to 3.0%. By adjusting the Y2O3 content to this range, the refractive index and devitrification resistance of the glass are improved.

[0054] (BaO)

[0055] Glass 10 may or may not contain BaO. In glass 10, the BaO content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.5% or more, more preferably 1.0% or more, more preferably 1.5% or more, more preferably 2.0% or more, more preferably 2.5% or more, and even more preferably 3.0% or more. In glass 10, the BaO content, expressed as a mole % based on oxides, is preferably 10% or less, more preferably 9.0% or less, more preferably 8.0% or less, more preferably 7.0% or less, more preferably 6.0% or less, more preferably 5.0% or less, and even more preferably 4.0% or less. In glass 10, the content of BaO, expressed as mole percent based on oxides, is preferably 0% to 10%, more preferably 0.5% to 9.0%, even more preferably 1.0% to 8.0%, even more preferably 1.5% to 7.0%, even more preferably 2.0% to 6.0%, even more preferably 2.5% to 5.0%, and even more preferably 3.0% to 4.0%. By setting the BaO content within this range, the refractive index, devitrification resistance, and visible light transmittance of the glass are improved.

[0056] (Bi2O3)

[0057] Glass 10 may or may not contain Bi2O3. In glass 10, the content of Bi2O3, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.5% or more, more preferably 1.0% or more, more preferably 2.0% or more, more preferably 4.0% or more, and even more preferably 6.0% or more. In glass 10, the content of Bi2O3, expressed as a mole % based on oxides, is preferably 30.0% or less, more preferably 25.0% or less, more preferably 20.0% or less, more preferably 15.0% or less, and even more preferably 10.0% or less. In glass 10, the content of Bi2O3, expressed as a mole % based on oxides, is preferably 0% to 30.0%, more preferably 0.5% to 25.0%, more preferably 1.0% to 20.0%, more preferably 2.0% to 20.0%, more preferably 4.0% to 15.0%, and even more preferably 6.0% to 10.0%. By setting the Bi2O3 content within this range, it is possible to achieve both high refractive index and high transmittance.

[0058] (Gd2O3)

[0059] Glass 10 preferably contains Gd₂O₃. In glass 10, the content of Gd₂O₃, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.0% or more, more preferably 2.0% or more, more preferably 3.0% or more, more preferably 4.0% or more, and even more preferably 4.5% or more. In glass 10, the content of Gd₂O₃, expressed as a mole % based on oxides, is preferably 10% or less, more preferably 9.0% or less, more preferably 8.0% or less, more preferably 7.0% or less, more preferably 6.0% or less, and even more preferably 5.0% or less. In glass 10, the content of Gd₂O₃, expressed as a mole % based on oxides, is preferably 0% to 10%, more preferably 1.0% to 9.0%, more preferably 2.0% to 8.0%, more preferably 3.0% to 7.0%, even more preferably 4.0% to 6.0%, and even more preferably 4.5% to 5.0%. By adjusting the Gd2O3 content to this range, the refractive index and devitrification resistance of the glass are improved.

[0060] (Nb2O5)

[0061] Glass 10 preferably contains Nb₂O₅. In glass 10, the Nb₂O₅ content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.0% or more, more preferably 2.0% or more, more preferably 3.0% or more, preferably 4.0% or more, and even more preferably 4.5% or more. In glass 10, the Nb₂O₅ content, expressed as a mole % based on oxides, is preferably 10.0% or less, more preferably 9.0% or less, more preferably 8.0% or less, more preferably 7.0% or less, preferably 6.0% or less, and even more preferably 5.5% or less. In glass 10, the Nb₂O₅ content, expressed as a mole % based on oxides, is preferably 0% to 10.0%, more preferably 1.0% to 9.0%, more preferably 2.0% to 8.0%, more preferably 3.0% to 7.0%, preferably 4.0% to 6.0%, even more preferably 5.0% to 6.0%, and also preferably 4.5% to 5.5%. By adjusting the Nb2O5 content to this range, the refractive index and devitrification resistance of the glass are improved.

[0062] (ZnO)

[0063] Glass 10 preferably contains ZnO. In glass 10, the ZnO content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.0% or more, more preferably 2.0% or more, and even more preferably 3.0% or more. In glass 10, the ZnO content, expressed as a mole % based on oxides, is preferably 20.0% or less, more preferably 15.0% or less, more preferably 10.0% or less, and even more preferably 6.0% or less. In glass 10, the ZnO content, expressed as a mole % based on oxides, is preferably 0% to 20.0%, more preferably 1.0% to 15.0%, more preferably 2.0% to 10%, and even more preferably 3.0% to 6.0%. By maintaining the ZnO content within this range, the liquidus temperature of the glass is lowered, and defect precipitation is suppressed.

[0064] (WO3)

[0065] Glass 10 may or may not contain WO3. In glass 10, the WO3 content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.1% or more, more preferably 0.2% or more, more preferably 0.3% or more, and even more preferably 0.5% or more. In glass 10, the WO3 content, expressed as a mole % based on oxides, is preferably 30.0% or less, more preferably 20.0% or less, more preferably 10.0% or less, more preferably 2.00% or less, and even more preferably 1.0% or less. In glass 10, the WO3 content, expressed as a mole % based on oxides, is preferably 0% to 30.0%, more preferably 0.1% to 20.0%, more preferably 0.2% to 10.0%, more preferably 0.3% to 2.0%, and even more preferably 0.5% to 1.0%. By setting the WO3 content within this range, a suitable reduction in the liquidus temperature and a high refractive index can be achieved.

[0066] (Ta2O5)

[0067] Glass 10 may or may not contain Ta2O5. In glass 10, the content of Ta2O5, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.1% or more, more preferably 0.2% or more, and even more preferably 0.3% or more. In glass 10, the content of Ta2O5, expressed as a mole % based on oxides, is preferably 10.0% or less, more preferably 5.0% or less, more preferably 1.0% or less, and even more preferably 0.5% or less. In glass 10, the content of Ta2O5, expressed as a mole % based on oxides, is preferably 0% to 10.0%, more preferably 0.1% to 5.0%, more preferably 0.2% to 1.0%, and even more preferably 0.3% to 0.5%. By setting the Ta2O5 content within this range, a high refractive index and a reduction in glass manufacturing costs can be appropriately achieved.

[0068] (P2O5)

[0069] Glass 10 may or may not contain P2O5. In glass 10, the P2O5 content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 0.5% or more, more preferably 1.0% or more, more preferably 1.5% or more, more preferably 2.0% or more, and even more preferably 2.5% or more. In glass 10, the P2O5 content, expressed as a mole % based on oxides, is preferably 30.0% or less, more preferably 25.0% or less, more preferably 20.0% or less, more preferably 15.0% or less, more preferably 10.0% or less, and even more preferably 5.0% or less. In glass 10, the P2O5 content, expressed as a mole % based on oxides, is preferably 0% to 30.0%, more preferably 0.5% to 25.0%, more preferably 1.0% to 20.0%, more preferably 1.5% to 15.0%, more preferably 2.0% to 10.0%, and even more preferably 2.5% to 5.0%. By maintaining the P2O5 content within this range, glass coloration is reduced, transmittance to short-wavelength visible light is increased, and stable glass formation is promoted, thereby improving the glass's resistance to devitrification.

[0070] (ZrO2)

[0071] Glass 10 preferably contains ZrO2. In glass 10, the ZrO2 content, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 1.0% or more, more preferably 2.0% or more, more preferably 3.0% or more, more preferably 4.0% or more, more preferably 5.0% or more, more preferably 6.0% or more, and even more preferably 7.0% or more. In glass 10, the ZrO2 content, expressed as a mole % based on oxides, is preferably 15.0% or less, more preferably 14.0% or less, more preferably 13.0% or less, more preferably 12.0% or less, more preferably 11.0% or less, more preferably 10.0% or less, more preferably 9.0% or less, and even more preferably 8.0% or less. In glass 10, the ZrO2 content, expressed as mole percent based on oxides, is preferably 0% to 15.0%, more preferably 1.0% to 14.0%, even more preferably 2.0% to 13.0%, even more preferably 3.0% to 12.0%, even more preferably 4.0% to 11.0%, even more preferably 5.0% to 10.0%, even more preferably 6.0% to 9.0%, and even more preferably 7.0% to 8.0%. By setting the ZrO2 content within this range, the coloration of the glass is reduced, the transmittance to short-wavelength visible light is increased, stable glass formation is promoted, and the devitrification resistance of the glass is improved.

[0072] (TiO2)

[0073] Glass 10 preferably contains TiO2. In glass 10, the content of TiO2, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 5.0% or more, more preferably 10.0% or more, more preferably 15.0% or more, more preferably 20.0% or more, preferably 25.0% or more, preferably 28.0% or more, preferably 29.0% or more, preferably 30.0% or more, and even more preferably 31.0% or more. In glass 10, the content of TiO2, expressed as a mole % based on oxides, is preferably 40.0% or less, more preferably 35.0% or less, more preferably 34.0% or less, more preferably 33.0% or less, more preferably 32.0% or less, preferably 31.5% or less, and even more preferably 31.0% or less. In glass 10, the TiO2 content, expressed as a mole percent based on oxides, is preferably 0% to 40%, more preferably 5.0% to 35%, even more preferably 10% to 34.0%, more preferably 15.0% to 33.0%, even more preferably 20.0% to 32.0%, preferably 25.0% to 32.0%, preferably 28.0% to 32.0%, preferably 29.0% to 32.0%, further preferably 30.0% to 32.0%, preferably 31.0% to 31.5%, and even more preferably 31.0%. By setting the TiO2 content within this range, the refractive index and chemical durability of the glass are improved.

[0074] (La2O3)

[0075] Glass 10 preferably contains La2O3. In glass 10, the content of La2O3, expressed as a mole % based on oxides, is preferably 0% or more, more preferably 5.0% or more, more preferably 10.0% or more, more preferably 15.0% or more, more preferably 16.0% or more, more preferably 17.0% or more, more preferably 18.0% or more, more preferably 19.0% or more, and even more preferably 20.0% or more. In glass 10, the content of La2O3, expressed as a mole % based on oxides, is preferably 40.0% or less, more preferably 35.0% or less, more preferably 30.0% or less, more preferably 28.0% or less, more preferably 27.0% or less, more preferably 26.0% or less, more preferably 25.0% or less, preferably 24.0% or less, and even more preferably 22.0% or less. In glass 10, the content of La2O3, expressed as mole percent based on oxides, is preferably 0% to 40.0%, more preferably 5.0% to 35.0%, even more preferably 10.0% to 35.0%, even more preferably 15.0% to 30.0%, even more preferably 16.0% to 28.0%, even more preferably 17.0% to 27.0%, even more preferably 18.0% to 26.0%, even more preferably 19.0% to 25.0%, further preferably 20.0% to 24.0%, and even more preferably 20.0% to 22.0%. By setting the La2O3 content within this range, it is possible to appropriately achieve improved high refractive index and chemical durability.

[0076] (Ti) 3＋ / Ti)

[0077] In the above, when glass 10 contains Ti, the Ti content is converted to TiO2 (i.e., all Ti is assumed to be tetravalent Ti). 4＋ The content of Ti is defined by its state (Ti). However, it is not limited to all Ti being tetravalent Ti (Ti). 4＋ In the state of ), there also exists at least a portion of Ti, for example, in trivalent Ti (Ti 3＋ The state includes the following situations.

[0078] In this case, the glass 10 contains trivalent Ti (Ti 3＋ The ratio of the content of Ti to the total content of Ti (Ti) 3＋ The mass ratio of Ti is preferably less than 0.100, more preferably 0.0800 or less, more preferably 0.0600 or less, more preferably 0.0500 or less, more preferably 0.0400 or less, more preferably 0.0300 or less, more preferably 0.0200 or less, and even more preferably 0.0100 or less. 3＋The mass ratio of Ti is more preferably 0 or more, more preferably 0.0005 or more, more preferably 0.0010 or more, more preferably 0.0020 or more, more preferably 0.0040 or more, more preferably 0.0060 or more, and even more preferably 0.0080 or more. 3＋ The content of trivalent Ti ( / Ti) is preferably less than 0.100 by mass, more preferably 0 to 0.0800, more preferably 0.0005 to 0.0600, more preferably 0.0010 to 0.0500, more preferably 0.0020 to 0.0400, more preferably 0.0040 to 0.0300, more preferably 0.0060 to 0.0200, and even more preferably 0.0080 to 0.0100. By setting the content of trivalent Ti within this range, high refractive index and high transmittance can be appropriately achieved. It should be noted that the total content of Ti refers to the total content of all valences of Ti, including divalent, trivalent, and tetravalent Ti.

[0079] The content of Ti can be determined by ICP mass spectrometry. For example, an Agilent 8800 instrument manufactured by Agilent Technologies can be used. 3＋ The content of [aspect name] can be determined using an electron spin resonance (ESR) device. For example, the Bruker EMXnano can be used as the measuring instrument. The ESR measurement conditions used in the above experiments are described below.

[0080] Ti 3＋ The content is determined as follows: the intensity is obtained by double integration of the peak at g = 1.93 ± 0.01, and compared with the intensity obtained in the same manner for a standard sample with a known concentration. g refers to the value calculated by the following formula. The integration range is set to integrate only the peak.

[0081] g = hν / βH (where h is Planck's constant, ν is the microwave frequency, β is the Bohr magneton of the electron, and H is the magnetic field of absorption.)

[0082] Sample size: 0.5g

[0083] Microwave frequency: 9.57~9.60GHz (adjusted for each measurement)

[0084] Output: 1~10mW (adjustable for each measurement)

[0085] Scan range: 1000–4000 Gauss

[0086] Modulation frequency: 100kHz

[0087] Modulation magnetic field: 5 Gauss

[0088] Magnetic field scanning time: 30–60 seconds (adjusted for each measurement)

[0089] Time constant: 1.28 msec

[0090] Measurement temperature: room temperature

[0091] In addition, the tetravalent Ti (Ti) contained in glass 10 4＋ The ratio of the content of Ti to the total content of Ti (Ti) 4 ＋ The mass ratio of Ti is preferably 0.9000 or more, more preferably 0.9200 or more, more preferably 0.9400 or more, and even more preferably 0.9600 or more. 4＋ The mass ratio of Ti is preferably 1.0000 or less, more preferably 0.9950 or less, even more preferably 0.9900 or less, and even more preferably 0.9850 or less. 4＋ The content of tetravalent Ti ( / Ti) is preferably 0.9000 to 1.0000 by mass, more preferably 0.9200 to 0.9950, even more preferably 0.9400 to 0.9900, and even more preferably 0.9600 to 0.9850. By setting the content of tetravalent Ti within this range, high refractive index and high transmittance can be appropriately achieved.

[0092] (Sb)

[0093] Glass 10 is preferably free of Sb. By being free of Sb, the environmental impact can be appropriately reduced. It should be noted that being free of Sb means that the presence of Sb as an unavoidable impurity is permitted.

[0094] Here, Sb does not refer only to the elemental metal containing Sb in glass 10, but rather to elemental metals and compounds that may contain Sb.

[0095] The presence of Sb can be determined by ICP mass spectrometry. For example, an Agilent 8800 from Agilent Technologies can be used as the measuring instrument.

[0096] (Properties of glass)

[0097] The following describes the characteristics of glass 10 other than those described above.

[0098] (transmittance τ) 440 )

[0099] The transmittance τ of glass 10 440Preferably, the transmittance τ is 0.800 or higher, more preferably 0.820 or higher, more preferably 0.840 or higher, more preferably 0.860 or higher, more preferably 0.870 or higher, more preferably 0.880 or higher, more preferably 0.890 or higher, and even more preferably 0.900 or higher. The transmittance τ of the glass 10... 440 Preferably, the transmittance τ is 1.000 or less, more preferably 0.990 or less, more preferably 0.980 or less, more preferably 0.970 or less, more preferably 0.965 or less, more preferably 0.960 or less, and even more preferably 0.955 or less. The transmittance τ of the glass 10... 440 Preferably, the transmittance τ is 0.820–1.000, more preferably 0.840–0.990, even more preferably 0.860–0.980, even more preferably 0.870–0.970, even more preferably 0.880–0.965, even more preferably 0.890–0.960, and even more preferably 0.900–0.955. This is achieved by adjusting the transmittance τ... 440 Within this range, visible light can be appropriately transmitted. It should be noted that, as mentioned above, the transmittance τ... 440 It is the internal transmittance of light with a wavelength of 440nm when the thickness is 10mm.

[0100] (transmittance τ) 460 )

[0101] The transmittance τ of glass 10 460 Preferably, the transmittance τ is 0.850 or higher, more preferably 0.870 or higher, more preferably 0.890 or higher, more preferably 0.900 or higher, more preferably 0.910 or higher, more preferably 0.920 or higher, and even more preferably 0.930 or higher. The transmittance τ of the glass 10... 460 Preferably, the transmittance τ is 1.000 or less, more preferably 0.990 or less, more preferably 0.980 or less, more preferably 0.975 or less, more preferably 0.970 or less, and even more preferably 0.965 or less. The transmittance τ of the glass 10... 460 Preferably, the transmittance τ is 0.870–1.000, more preferably 0.890–0.990, even more preferably 0.900–0.980, even more preferably 0.910–0.975, even more preferably 0.920–0.970, and even more preferably 0.930–0.965. This is achieved by adjusting the transmittance τ... 460 Within this range, visible light can be appropriately transmitted. It should be noted that, as mentioned above, the transmittance τ... 460 It is the internal transmittance of light with a wavelength of 460nm when the thickness is 10mm.

[0102] (wavelength λ5)

[0103] The wavelength λ5 of the glass 10 is preferably 430 nm or less, more preferably 425 nm or less, more preferably 420 nm or less, more preferably 415 nm or less, more preferably 410 nm or less, and even more preferably 405 nm or less. The wavelength λ5 of the glass 10 is more preferably 350 nm or more, more preferably 355 nm or more, more preferably 360 nm or more, more preferably 365 nm or more, and even more preferably 370 nm or more. The wavelength λ5 of the glass 10 is preferably 430 nm or less, more preferably 350 nm to 425 nm, more preferably 355 nm to 420 nm, more preferably 360 nm to 415 nm, more preferably 365 nm to 410 nm, and even more preferably 370 nm to 405 nm. By setting the wavelength λ5 to this range, visible light can be appropriately transmitted. It should be noted that wavelength λ5 refers to the wavelength at which the internal transmittance of the display is 5% when the plate thickness is 10 mm.

[0104] (Abbe number v) d )

[0105] The Abbe number v of glass 10 d Preferably, the Abbe number v is 17.00 or higher, more preferably 19.00 or higher, even more preferably 23.00 or higher, even more preferably 25.00 or higher, even more preferably 26.00 or higher, and still more preferably 27.00 or higher. d Preferably, the Abbe number v is 35.00 or less, more preferably 33.00 or less, more preferably 32.00 or less, more preferably 31.00 or less, more preferably 30.00 or less, and even more preferably 29.00 or less. d Preferably, it is 17.00 to 35.00, more preferably 19.00 to 33.00, even more preferably 23.00 to 32.00, even more preferably 25.00 to 31.00, even more preferably 26.00 to 30.00, and even more preferably 27.00 to 29.00. It should be noted that the Abbe number v... d It represents the value of the property of dispersion. Abbe number v d It can be determined using the V-block method.

[0106] (Devitrification temperature)

[0107] The devitrification temperature of glass 10 is preferably below 1250°C, more preferably below 1240°C, more preferably below 1230°C, more preferably below 1220°C, more preferably below 1210°C, more preferably below 1200°C, more preferably below 1190°C, more preferably below 1180°C, more preferably below 1170°C, more preferably below 1160°C, more preferably below 1150°C, more preferably below 1140°C, more preferably below 1130°C, and even more preferably below 1120°C. By setting the devitrification temperature within this range, the temperature of the melting raw materials during the manufacture of glass 10 can be kept relatively low, which can suppress the melting and mixing of Pt and Fe contained in the raw materials and equipment into the glass, thereby reducing the content of Pt and Fe.

[0108] The devitrification temperature can be determined by the following method. The sample glass is crushed and passed through a 4 mm sieve, leaving glass particles on a 2 mm sieve. These glass particles are immersed in ethanol and ultrasonically cleaned, then dried in a desiccator. Approximately 5 g of the dried glass particles are placed in a platinum dish and maintained at 10°C increments of 10°C for 1 hour. After natural cooling, the glass particles are observed under a microscope for crystal precipitation. The lowest temperature at which no crystals with a long side or major diameter greater than 1 μm are observed is taken as the devitrification temperature.

[0109] (Young's modulus E)

[0110] The Young's modulus E of glass 10 is preferably 90 GPa or more, more preferably 95 GPa or more, more preferably 100 GPa or more, more preferably 105 GPa or more, more preferably 110 GPa or more, more preferably 117 GPa or more, more preferably 120 GPa or more, more preferably 122 GPa or more, more preferably 124 GPa or more, and even more preferably 126 GPa or more. The Young's modulus E of glass 10 is preferably 155 GPa or less, more preferably 150 GPa or less, more preferably 148 GPa or less, more preferably 145 GPa or less, more preferably 143 GPa or less, more preferably 141 GPa or less, more preferably 139 GPa or less, more preferably 137 GPa or less, and even more preferably 135 GPa or less. The Young's modulus E of glass 10 is preferably 95 GPa to 155 GPa, more preferably 100 GPa to 150 GPa, even more preferably 105 GPa to 148 GPa, even more preferably 110 GPa to 145 GPa, even more preferably 117 GPa to 143 GPa, even more preferably 120 GPa to 141 GPa, even more preferably 122 GPa to 139 GPa, even more preferably 124 GPa to 137 GPa, and even more preferably 126 GPa to 135 GPa. By achieving such a high Young's modulus, breakage of glass 10 can be appropriately suppressed. It should be noted that the Young's modulus can be measured using an OLYMPUS 38DL PLUS measuring instrument based on the propagation of ultrasonic waves.

[0111] (Specific gravity d)

[0112] The specific gravity d of glass 10 is preferably 6.20 g / cm³. 3 The preferred value is 6.17 g / cm³. 3 The following is more preferred: 5.70 g / cm³ 3 The following is more preferably 5.50 g / cm³. 3 The following is more preferably 5.40 g / cm³. 3 The following is a preferred value: 5.30 g / cm³ 3 The preferred value is 5.20 g / cm³. 3 The following is more preferably 5.00 g / cm³ 3 The following is further preferred: 4.50 or less. The specific gravity d of glass 10 is preferably 3.40 g / cm³. 3 The above, more preferably 3.50 g / cm³ 3 The above, more preferably 3.60 g / cm³ 3 The above, more preferably 3.70 g / cm³ 3 The above, more preferably 3.80 g / cm³ 3 The above is further preferably 3.90 g / cm³. 3The specific gravity d of glass 10 is preferably 3.40 g / cm³. 3 ~6.17g / cm 3 More preferably 3.50 g / cm³ 3 ~5.70g / cm 3 More preferably 3.60 g / cm³ 3 ~5.50g / cm 3 More preferably 3.70 g / cm³ 3 ~5.40g / cm 3 More preferably 3.80 g / cm³ 3 ~5.30g / cm 3 The preferred value is 3.90 g / cm³. 3 ~5.20g / cm 3 Further preferred is 4.00 g / cm³ 3 ~5.00g / cm 3 By making the specific gravity so low, the processing of glass 10 becomes easy. It should be noted that the specific gravity d can be determined using Archimedes' method.

[0113] (The form of glass)

[0114] The glass 10 in this embodiment is preferably optical glass, and preferably a glass plate with a thickness of 0.01 mm to 2.0 mm. If the thickness is 0.01 mm or more, breakage during processing and manufacturing of the glass 10 can be suppressed. In addition, bending of the glass 10 due to its own weight can be suppressed. This thickness is more preferably 0.1 mm or more, further preferably 0.2 mm or more, and even more preferably 0.3 mm or more. On the other hand, if the thickness is 2.0 mm or less, the optical element obtained using the glass 10 can be made lighter. This thickness is more preferably 1.5 mm or less, further preferably 1.0 mm or less, and even more preferably 0.8 mm or less.

[0115] In this embodiment, when the glass 10 is a glass plate, the area of ​​the main surface is preferably 8 cm². 2 That's all. If the area is 8cm² 2 This allows for the configuration of a large number of optical components, increasing productivity. A more preferable area is 30 cm². 2 The above is further optimized to 170cm. 2 The above is further optimized to be 300cm. 2 The above is particularly preferred, with 1000cm being the ideal size. 2 That's all. On the other hand, if the area is 6500cm² 2 This makes the handling of the glass plate easier and reduces the risk of breakage during processing. A more preferred area is 4500 cm². 2 The following is a further preferred size: 4000cm2 The following is a further preferred size: 3000cm 2 The following is particularly preferred: 2000cm 2 the following.

[0116] In this embodiment, when the glass 10 is a glass plate, the 25cm of the main surface... 2 The local thickness variation (LTV) is preferably 2 μm or less. With flatness within this range, nanostructures of the desired shape can be formed on the main surface using techniques such as imprinting, and the desired light-guiding properties can be obtained. In particular, ghosting and distortion caused by differences in optical path length can be prevented in the light guide. This LTV is more preferably 1.5 μm or less, even more preferably 1.0 μm or less, and particularly preferably 0.5 μm or less.

[0117] When the glass 10 of this embodiment is made into a circular glass plate with a diameter of 8 to 12 inches, the warpage is preferably 50 μm or less. If the warpage of the glass 10 is 50 μm or less, a nanostructure of the desired shape can be formed on the main surface using techniques such as imprinting, and the desired light guiding properties can be obtained. When multiple light guides are obtained, light guides with stable quality can be obtained. The warpage of the glass 10 is more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 20 μm or less.

[0118] Furthermore, when the glass 10 of this embodiment is made into a circular glass plate with a diameter of 6 inches, the warpage is preferably 30 μm or less. If the warpage of the glass 10 is 30 μm or less, a nanostructure of the desired shape can be formed on the main surface using techniques such as imprinting, and the desired light guiding properties can be obtained. When multiple light guides are obtained, light guides with stable quality can be obtained. The warpage of the glass 10 is more preferably 20 μm or less, further preferably 15 μm or less, and particularly preferably 10 μm or less.

[0119] Furthermore, when the glass 10 of this embodiment is made into a square glass plate with each side being 6 inches, the warpage is preferably 100 μm or less. If the warpage of the glass 10 is 100 μm or less, a nanostructure of the desired shape can be formed on the main surface using techniques such as imprinting, and the desired light guiding properties can be obtained. When multiple light guides are obtained, light guides with stable quality can be obtained. The warpage of the glass 10 is more preferably 70 μm or less, further preferably 50 μm or less, even more preferably 35 μm or less, and particularly preferably 20 μm or less.

[0120] Figure 2This is a cross-sectional view of the glass of this embodiment when it is made into a glass plate. "Warp" refers to the difference C between the maximum value B and the minimum value A of the distance in the vertical direction between the reference line G1D of the glass plate G1 and the center line G1C of the glass plate G1 when the glass 10 of this embodiment is made into a glass plate G1.

[0121] The intersection of the aforementioned orthogonal arbitrary cross section with the main surface G1F of glass plate G1 is designated as the baseline G1A. The intersection of the aforementioned orthogonal arbitrary cross section with another main surface G1G of glass plate G1 is designated as the upper line G1B. Here, the center line G1C is a line connecting the centers of glass plate G1 in the thickness direction. The center line G1C is calculated by finding the midpoints of the baseline G1A and the upper line G1B relative to the direction of laser irradiation described later.

[0122] The baseline G1D is determined as follows. First, based on a measurement method that eliminates the influence of self-weight, the baseline G1A is calculated. A straight line is then derived from this baseline G1A using the least squares method. The derived straight line is the baseline G1D. A known method can be used as the measurement method for eliminating the influence of self-weight.

[0123] For example, the main surface G1F of glass plate G1 is supported at three points, and a laser displacement meter is used to irradiate the glass plate G1 with a laser to measure the height of the main surface G1F and another main surface G1G of glass plate G1 from any reference plane.

[0124] Next, the glass plate G1 is flipped over, and three points of another main surface G1G are supported opposite to the three points supporting one main surface G1F. The heights of the main surface G1F and the other main surface G1G of the glass plate G1 are measured from any reference plane.

[0125] The average height of each measurement point before and after flipping is calculated to eliminate the influence of self-weight. For example, before flipping, the height of the main surface G1F is measured as described above. After flipping the glass plate G1, the height of the other main surface G1G is measured at the position corresponding to the measurement point of the main surface G1F. Similarly, before flipping, the height of the other main surface G1G is measured. After flipping the glass plate G1, the height of the main surface G1F is measured at the position corresponding to the measurement point of the other main surface G1G.

[0126] Warpage can be measured, for example, by a laser displacement meter.

[0127] Furthermore, in the glass 10 of this embodiment, the surface roughness Ra of the main surface is preferably 2 nm or less. With Ra within this range, nanostructures of desired shapes can be formed on the main surface using techniques such as imprinting, and desired light-guiding properties can be obtained. In particular, diffuse reflection at the interface is suppressed in the light guide, preventing ghosting and distortion. Ra is more preferably 1.7 nm or less, even more preferably 1.4 nm or less, even more preferably 1.2 nm or less, and particularly preferably 1 nm or less. Here, the surface roughness Ra is the arithmetic mean roughness defined in JIS B0601 (2001). In this specification, the value is obtained by measuring a 10 μm × 10 μm area using an atomic force microscope (AFM).

[0128] (Methods for manufacturing glass)

[0129] The manufacturing method of the glass 10 in this embodiment is not particularly limited. The preferred manufacturing method of the glass 10 will be described below.

[0130] This embodiment includes the steps of: preparing raw materials for glass 10; melting the raw materials; and cooling the melted raw materials to obtain glass 10. In this manufacturing method, existing sheet glass manufacturing methods can be used. For example, known methods such as float glass, melting glass, and rolling glass can be used.

[0131] Regarding the raw materials for glass 10, types corresponding to the desired composition of the glass 10 are selected, and they are mixed in a proportion corresponding to the desired composition of the glass 10. In this embodiment, the ratio of Fe contained in the raw materials to the total amount of the raw materials (Fe / total raw materials) is preferably 0 ppm or more, more preferably 0.2 ppm or more, more preferably 0.5 ppm or more, more preferably 0.8 ppm or more, more preferably 1.0 ppm or more, and even more preferably 1.5 ppm or more. The ratio of Fe contained in the raw materials to the total amount of the raw materials (Fe / total raw materials) is preferably 15.0 ppm or less, more preferably 10.0 ppm or less, more preferably 7.0 ppm or less, more preferably 5.0 ppm or less, more preferably 4.0 ppm or less, and even more preferably 3.0 ppm or less. The ratio of Fe contained in the raw material to the total amount of the raw material (Fe / total raw material) is preferably 0 ppm to 15.0 ppm, more preferably 0.2 ppm to 10.0 ppm, more preferably 0.5 ppm to 7.0 ppm, more preferably 0.8 ppm to 5.0 ppm, more preferably 1.0 ppm to 4.0 ppm, and even more preferably 1.5 ppm to 3.0 ppm. This reduces the Fe content of the glass 10.

[0132] The Fe here does not refer only to the elemental metal Fe contained in the raw material, but can include elemental metals and compounds containing Fe.

[0133] The Fe content can be determined by ICP mass spectrometry. For example, the Agilent 8800 from Agilent Technologies can be used as the measuring instrument.

[0134] In the step of melting the raw material, the raw material is placed into a container such as a crucible, and the raw material placed in the container is heated to melt it. The container can be made of any material; in this embodiment, a container containing Pt is used.

[0135] The heating temperature for melting the raw materials is preferably 950°C or higher, more preferably 1000°C or higher, more preferably 1050°C or higher, more preferably 1100°C or higher, and even more preferably 1120°C or higher. The heating temperature for melting the raw materials is preferably 1600°C or lower, more preferably 1500°C or lower, more preferably 1400°C or lower, more preferably 1350°C or lower, and even more preferably 1300°C or lower. The heating temperature for melting the raw materials is preferably 950°C to 1600°C, more preferably 1000°C to 1500°C, more preferably 1050°C to 1400°C, more preferably 1100°C to 1350°C, and even more preferably 1120°C to 1300°C. By maintaining the heating temperature within this range, the melting of Pt contained in the container and Fe contained in the raw materials is suppressed, thereby reducing the Pt and Fe content of the glass 10.

[0136] (Effect)

[0137] As described above, the glass 10 of the first aspect of this disclosure comprises La2O3 and B2O3, and has a refractive index n. d The total content of Bi2O3 and B2O3 is less than 80% in mol% based on oxides, and the total content of Pt and Fe is 0.5ppm to 15.0ppm by mass ratio. The parameter A specified by formula (1) is 0.870 or more.

[0138] The inventors have discovered that high-refractive-index glasses containing La₂O₃ and B₂O₃, with a combined Bi₂O₃ content of less than 80%, tend to have lower transmittance. Furthermore, the inventors have found that high-refractive-index glasses tend to have higher melting temperatures, thus increasing the leaching of Pt and Fe during the manufacturing process, resulting in higher Pt and Fe content in the manufactured glass. If the Pt and Fe content is high, Pt and Fe are more likely to precipitate as defects.

[0139] The inventors conducted in-depth research on this matter and discovered that by maintaining a total Pt and Fe content of 0.5 ppm to 15 ppm and a parameter A of 0.880 or higher, the precipitation of Pt and Fe as defects can be suppressed, and the decrease in transmittance can also be suppressed. In other words, the glass disclosed herein, by satisfying the above conditions, can appropriately maintain a balance between the amount of Pt and Fe, transmittance, and manufacturing conditions, thereby achieving both high refractive index and high transmittance while suppressing defect precipitation.

[0140] The glass 10 of the second aspect of this disclosure is the glass 10 of the first aspect, and the parameter B specified in preferred formula (2) is 2.075 or higher. Even with a high refractive index, the glass 10 of this disclosure can maintain a high transmittance of visible light.

[0141] The glass 10 of the third aspect of this disclosure is the glass 10 of the first or second aspect, and preferably has a devitrification temperature of 1250°C or below. By setting the devitrification temperature of the glass 10 of this disclosure to 1250°C or below, the temperature at which the raw materials are melted during the manufacture of the glass 10 can be relatively low, thereby reducing the content of Pt and Fe.

[0142] The glass 10 of the fourth aspect of this disclosure is the glass 10 of any one of the first to third aspects, and preferably has a Young's modulus of 90 GPa or more. By having a Young's modulus of 90 GPa or more, the glass 10 of this disclosure can appropriately suppress breakage.

[0143] The glass 10 of the fifth aspect of this disclosure is the glass 10 of any one of the first to fourth aspects, and preferably, the ratio of the trivalent Ti content to the total Ti content is less than 0.1000 by mass. This allows for the appropriate achievement of high refractive index and high transmittance.

[0144] The glass 10 of the sixth aspect of this disclosure is the glass 10 of any one of the first to fifth aspects, and preferably does not contain Sb. Therefore, high refractive index and high transmittance can be appropriately achieved.

[0145] The glass 10 of the seventh aspect of this disclosure is the glass 10 of any one of the first to sixth aspects, and preferably contains, in mole percent based on oxides: SiO2: 0% to 20.0%, B2O3: 0% to 30.0%, Y2O3: 0% to 10.0%, BaO: 0% to 10.0%, Bi2O3: 0% to 30.0%, Gd2O3: 0% to 10.0%, Nb2O5: 0% to 10.0%, ZnO: 0% to 20.0%, WO3: 0% or more and less than 30.0%, Ta2O5: 0% to 10.0%, P2O5: 0% to 30.0%, ZrO2: 0% to 15.0%, TiO2: 0% to 40.0%, and La2O3: 0% to 40.0%. This allows for the appropriate achievement of high refractive index and high transmittance.

[0146] The glass 10 of the eighth aspect of this disclosure is the glass 10 of any one of the first to seventh aspects, and preferably has a specific gravity of 6.20 g / cm³. 3 The following. By making the specific gravity so low, the processing of glass 10 becomes easy.

[0147] The glass 10 of the ninth aspect of this disclosure is the glass 10 of any one of the first to eighth aspects, and is preferably used as a light guide plate. The glass 10 of this disclosure can be suitably used as a light guide plate.

[0148] The glass manufacturing method of the tenth aspect of this disclosure includes: heating a raw material at 950°C to 1600°C to melt the raw material; and cooling the melted raw material to obtain the glass 10 described in any one of the first to ninth aspects. According to this disclosure, by heating the raw material to the above-mentioned range, a glass can be manufactured that can reduce the content of Pt and Fe, achieve high refractive index and high transmittance, and suppress the precipitation of defects.

[0149] (Example)

[0150] Next, the embodiments will be described. Tables 1 and 2 are tables showing the glass used in each example. It should be noted that the implementation method can be modified as long as the effect of the invention is achieved.

[0151]

[0152]

[0153] (Example 1)

[0154] In Example 1, glass with thicknesses of 10 mm and 1 mm was manufactured using the composition listed in Table 1. Specifically, the raw materials with the composition shown in Table 1 were uniformly mixed and melted in a platinum crucible at 1300°C for 2 hours to produce a homogeneous molten glass. Next, the molten glass was poured into a carbon mold with dimensions of 60 mm (length) x 50 mm (width) x 30 mm (height). Then, it was held at 660°C for 1 hour and cooled to room temperature at a rate of approximately 1°C / minute to obtain a glass block. Next, the glass block was cut into 30 mm x 30 mm pieces using a cutting machine (a small cutting machine manufactured by Maruto). The thickness was adjusted and the surface was ground using a grinding machine (SGM-6301 manufactured by Hidewa Kogyo Co., Ltd.) and a single-sided grinding machine (EJ-380IN manufactured by Engis Co., Ltd., Japan) to manufacture glass with dimensions of 30 mm x 30 mm and thicknesses of 10 mm and 1 mm.

[0155] The total Pt and Fe content of the glass in Example 1 was determined. The determination method used was the method described in the above embodiments.

[0156] The proportion of glass in Example 1 (Ti) was determined. 3＋ / Ti). The determination method uses the method described in the above embodiments.

[0157] The refractive index n of the glass in Example 1 was determined. d Transmittance τ 440 Transmittance τ 460 Wavelength λ5, Young's modulus E, specific gravity d, Abbe number v d Devitrification temperature. The method used is the one described in the above embodiments.

[0158] The results of each measurement are shown in Table 1.

[0159] (Example 2~Example 73)

[0160] In Examples 2 through 73, the compositions were as shown in Table 1 or Table 2, except that the glass was manufactured using the same method as in Example 1. The measurement results of the glass in each example are shown in Table 1.

[0161] (evaluate)

[0162] For each glass example, the optical properties and defect precipitation were evaluated.

[0163] In the evaluation of optical properties, transmittance τ is used. 440 A value greater than 0.840 and a refractive index n d A score of 2.0100 or higher is rated as 0, and a score of × is rated if at least one of them is not met.

[0164] In the evaluation of defect precipitation, cases where no defects are observed by visual inspection are rated as 0, and cases where defects are observed are rated as ×.

[0165] As shown in Table 1, it can be seen that in Examples 72-73, which are comparative examples, at least one of the evaluations of optical properties and defect precipitation is ×, and it is impossible to suppress defect precipitation while achieving both high refractive index and high transmittance. It can be seen that in Examples 1-71, which are embodiments, both the evaluations of optical properties and defect precipitation are 0, and it is possible to suppress defect precipitation while achieving both high refractive index and high transmittance.

[0166] The embodiments of the present invention have been described above, but the embodiments are not limited to the content of these embodiments. Furthermore, the above-described constituent elements include constituent elements that are easily assumed by those skilled in the art, substantially identical constituent elements, and constituent elements of so-called equal scope. Furthermore, the above-described constituent elements can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the constituent elements can be made without departing from the spirit of the above-described embodiments.

[0167] Symbol Explanation

[0168] 10 Glass

Claims

1. A glass comprising La₂O₃ and B₂O₃, Refractive index n d It is above 2.0100. Expressed as mol% based on oxides, the combined content of Bi₂O₃ and B₂O₃ is less than 80%. The total content of Pt and Fe, by mass ratio, is 0.5 ppm to 15.0 ppm. The parameter A specified by equation (1) is 0.870 or higher. A=τ 440 +0.005×(Pt+Fe) ···(1) in, τ 440 To convert the internal transmittance to light with a wavelength of 440nm for a thickness of 10mm, (Pt + Fe) represents the total content of Pt and Fe by mass ratio, expressed in ppm.

2. The glass according to claim 1, wherein, The parameter B specified by equation (2) is 2.075 or higher. B=τ 460 +0.583×n d ···(2) Where, τ 460 This is the internal transmittance of light with a wavelength of 460nm when the thickness is 10mm.

3. The glass according to claim 1 or 2, wherein, The devitrification temperature is below 1250℃.

4. The glass according to claim 1 or 2, wherein, The Young's modulus is above 90 GPa.

5. The glass according to claim 1 or 2, wherein, By mass ratio, the content of trivalent Ti relative to the total content of Ti is less than 0.

100.

6. The glass according to claim 1 or 2, wherein, It does not contain Sb.

7. The glass according to claim 1 or 2, wherein, Expressed as mol% based on oxides, it contains: SiO2: 0%–20.0% B2O3: 0%–30.0% Y2O3: 0%~10.0% BaO: 0%–10.0% Bi2O3: 0%–30.0% Gd2O3: 0%–10.0% Nb2O5: 0%–10.0% ZnO: 0%–20.0% WO3: 0% or more and less than 30.0% Ta2O5: 0%–10.0% P2O5: 0%–30.0% ZrO2: 0%–15.0% TiO2: 0%–40.0% La2O3: 0%–40.0%.

8. The glass according to claim 1 or 2, wherein, Specific gravity is 6.20 g / cm³ 3 the following.

9. The glass according to claim 1 or 2, which is used as a light guide plate.

10. A method for manufacturing glass, comprising: The raw material is heated to 950℃~1600℃ to melt it; as well as The molten raw material is cooled to obtain the glass according to claim 1 or 2.

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