Glass with high refractive index, preparation method and application

Abstract

The invention relates to the technical field of optical glass manufacturing, in particular to high-refractive-index glass as well as a preparation method and application thereof. The transition metal is less than 4 ppm by mass, and the transition metal comprises one or more of Fe, Cr, Ni, Cu, Mn, Co and V; the oxide is prepared from the following components in mole percent based on the oxide: 17 mol% to 49 mol% of Bi2O3, 2.7 mol% to 15.7 mol% of Nb2O5, 8.5 mol% to 39 mol% of TeO2, 2 mol% to 19.5 mol% of P2O5, 11.3 mol% to 41 mol% of B2O3, 0 mol% to 1 mol% of TiO2, 0 mol% to 1 mol% of Ta2O5, 0 mol% to 1 mol% of WO3 and 0.5 mol% to 16.5 mol% of ZnO, and Bi2O3 / (TeO2 + TiO2 + WO3 + Nb2O5 + Bi2O3) * 100 is more than or equal to 30 and less than or equal to 75. Tests show that when the thickness of the glass is 10 mm, the refractive index of the glass is 2.09-2.35, and the transmittance of the glass with the wavelength lambda 70 smaller than 450 nm is 82.4%-96.8%. The problems that in the prior art, high-refractive-index glass is low in refractive index and light transmittance and low in performance and cost ratio, and the increasingly-developed visual experience and development requirements of head-mounted displays cannot be met are solved.

Description

Technical Field

[0001] The invention relates to the technical field of optical glass manufacturing, in particular to high refractive index glass, a preparation method and application thereof. Background Art

[0002] High refractive index glass generally refers to glass with a refractive index greater than 1.5. It is a special type of optical glass material with a higher refractive index than ordinary glass. It has the advantages of higher refractive index, excellent optical performance, high precision and good chemical stability, and is widely used. In the field of optical lenses, high refractive index glass is widely used to prepare optical lenses with high refractive index, such as high refractive index contact lenses, etc., which helps to improve the light transmittance and perspective area of ​​the lens, thereby improving the overall optical performance. High refractive index glass can be used to prepare various optical components, such as prisms, reflectors, filters, etc., and can be used in astronomical telescopes, lasers and other equipment. In the field of electronic devices, high refractive index glass also plays an important role. For example, it can be used to manufacture artificial eye lenses, which are used as artificial prostheses in ophthalmic surgery. Due to its high refractive index characteristics, the lens is closer to the tissue of the eyeball and is more easily accepted by the body. In the field of scientific research, high refractive index glass also has important applications. It can be used to prepare high-density optical recording media, manufacture laser sound absorption media, etc. These applications can greatly promote scientific and technological progress. High refractive index glass also plays a key role in the field of display manufacturing. Its high refractive index characteristics can greatly improve the resolution and color saturation of pixels, thereby achieving a clearer and more realistic display effect. High refractive index glass has become an indispensable material in these fields due to its unique properties. With the continuous development of science and technology, the application prospects of high refractive index glass will be broader.

[0003] Especially in recent years, in the realization of wearable devices such as head-mounted displays including augmented reality (AR), virtual reality (VR) and mixed reality (MR), the light guide plate is a key component responsible for guiding images or light into the user's field of view. High refractive index glass can more effectively change the propagation path of light, thereby improving the utilization efficiency of light and reducing light loss. Therefore, the light guide plate is required to have a higher refractive index and higher transmittance for visible light. Although optical glass with high refractive index and high transmittance is currently available, its refractive index and transmittance still cannot meet the visual experience and development needs of head-mounted displays. Summary of the invention

[0004] In view of the problems that the high refractive index glass in the prior art has low refractive index and transmittance, low performance-to-cost ratio, and cannot meet the visual experience and development needs of the increasingly developed head-mounted displays, the present invention provides a high refractive index glass, a preparation method and application.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a high refractive index glass, comprising the following components: a transition metal and an oxide; the transition metal is less than 4 ppm by mass, and the transition metal comprises one or more of Fe, Cr, Ni, Cu, Mn, Co and V;

[0007] In terms of molar percentage based on oxides, the oxides include: 17mol% to 49mol% Bi2O3, 2.7mol% to 15.7mol% Nb2O5, 8.5mol% to 39mol% TeO2, 2mol% to 19.5mol% P2O5, 11.3mol% to 41mol% B2O3, 0mol% to 1mol% TiO2, 0mol% to 1mol% Ta2O5, 0mol% to 1mol% WO3 and 0.5mol% to 16.5mol% ZnO, 30≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤75.

[0008] Preferably, Pb is also included, and the content of Pb is less than 500 ppm by mass.

[0009] Preferably, impurities are also included, and the impurities include SiO2 and / or Al2O3, and the impurities are less than 3% in molar percentage based on the oxide.

[0010] Furthermore, based on the molar percentage of the oxide, the content of Bi2O3 is 25mol% to 32mol%, the content of Nb2O5 is 4.7mol% to 8.7mol%, the content of TeO2 is 23.5mol% to 29mol%, the content of P2O5 is 8mol% to 12.5mol%, the content of B2O3 is 15.3mol% to 31mol%, the content of TiO2 is 0mol% to 0.1mol%, the content of Ta2O5 is 0mol% to 0.1mol%, the content of WO3 is 0mol% to 0.1mol%, and the content of ZnO is 4.5mol% to 10.5mol%.

[0011] Furthermore, based on the molar percentage of the oxides, 50 mol%≤(TeO2+TiO2+WO3+Nb2O5+Bi2O3).

[0012] Preferably, based on the molar percentage of the oxide, 40≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤55.

[0013] Furthermore, when the thickness is 10 mm, the refractive index is 2.09 to 2.35, which is smaller than the wavelength λ of 450 nm. 70 The transmittance is 82.4% to 96.8%, and the wavelength λ 70 It is the wavelength that shows an external transmittance of 70% when the thickness is 10 mm.

[0014] The method for preparing the high refractive index glass as described above comprises:

[0015] Mixing raw materials according to components and melting them to obtain molten glass;

[0016] The molten glass is shaped and annealed to obtain high refractive index glass.

[0017] Furthermore, during the melting process, the container material for melting the glass is Pt or Pt alloy, and water vapor is added to the melting atmosphere or a gas containing water vapor is filled into the melt for bubbling treatment to increase the moisture content of the molten glass.

[0018] Such as the application of high refractive index glass in the preparation of head-mounted displays.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] A high refractive index glass of the present invention comprises the following components: a transition metal and an oxide; the transition metal comprises one or more of Fe, Cr, Ni, Cu, Mn, Co and V, the transition metal is a coloring transition metal, and it is allowed to be introduced as an impurity, but by controlling the content of the coloring transition metal to be below 4ppm, the reduction of the visible light transmittance of the high refractive index glass can be effectively suppressed. In terms of molar percentage based on oxides, the oxides include: Bi2O3, Nb2O5, TeO2, P2O5, B2O3, TiO2, Ta2O5, WO3 and ZnO; wherein Bi2O3 is an element with a large atomic radius and atomic mass, a low melting point, a large density and a large dielectric constant. In glass, it has the effect of reducing the high-temperature viscosity of the glass and significantly increasing the refractive index of the glass. The content of Bi2O3 in the high-refractive-index glass is greater than or equal to 17%, which can ensure that the glass has a high refractive index. The content of Bi2O3 is less than or equal to 49%, which enables the high-refractive-index glass to maintain a high transmittance. It can be seen that by having the Bi2O3 content within this range, the high-refractive-index glass can achieve a high refractive index while maintaining a high transmittance to visible light. Nb2O5 has the effect of increasing the high refractive index of glass and reducing dispersion, has an excellent effect on increasing the refractive index of glass and reducing the liquidus temperature, and also has the effect of improving the anti-crystallization and chemical durability of glass. Its content is too low to meet the purpose of increasing the refractive index of glass, but when the content is too high, it may tend to lose oxygen and form a lower oxidation level, which can cause the deterioration of the internal transmittance of glass. Therefore, the content of Nb2O5 in the high refractive index glass is preferably greater than 2.7%, which increases the refractive index of glass. In addition, the content of Nb2O5 is preferably less than 15.7%, which can maintain the stability of glass while increasing the refractive index of glass. TeO2 usually significantly increases the refractive index of glass, helps to improve the light transmittance and dispersion performance of glass, and an appropriate amount of TeO2 can enhance the chemical stability of glass. The content of TeO2 in the high refractive index glass is preferably greater than 8.5%, which can further increase the refractive index of glass. The content of TeO2 is preferably less than 39%, which can achieve the improvement of the refractive index of glass while ensuring the high transmittance of glass. P2O5 is a glass network former that is interconnected by (PO4)3-tetrahedrons. It has the characteristics of high solubility for rare earth ions, low dispersion, increased refractive index, and reduced density. However, it is corrosive to refractory crucibles during melting, and the concentration needs to be controlled. High refractive index glass preferably contains P2O5 as an essential component. Even if it does not contain P2O5, glass can be obtained, but the glass becomes unstable and the manufacturability deteriorates. The content of P2O5 in the high refractive index glass is preferably greater than 2.0%, which can maintain the stability of the glass. In addition, the content of P2O5 in the high refractive index glass is preferably less than 19.5%, which can improve the refractive index of the glass while ensuring the stability and manufacturability of the glass.B2O3 can be used as a matrix to form a network structure, and can generate glass alone. Its addition can improve the toughness of glass. At the same time, B2O3 is also a good cosolvent, which can greatly reduce the melting temperature of glass and is also beneficial to the vitrification process. However, too much content is not conducive to the thermal stability of glass, the improvement of refractive index and the corrosion of refractory materials. The concentration needs to be controlled. The content of B2O3 in high-refractive index glass is preferably greater than 11.3%, which can maintain the stability of glass. The content of B2O3 is less than 41%, which can ensure a high refractive index. The effect of TiO2 on improving the refractive index is very obvious, which helps to maintain a relatively low density. Many glasses with higher refractive index contain higher TiO2, but TiO2 also has a significant coloring effect. At the same time, because it is a nucleating agent, it can help crystal growth, which makes thermal post-processing such as pressing more difficult. The content of TiO2 in high-refractive index glass is preferably less than 1.0%, which can help nucleation and ensure high transmittance. Ta2O5 has the function of increasing the refractive index and maintaining the low dispersion of the glass. The content of Ta2O5 in the high refractive index glass is less than 1.0%, which can increase the refractive index of the glass. However, if the content is too high, the glass will become unstable and easy to lose transparency. In addition, due to the high price of Ta2O5, the cost increases with the amount used. By keeping the content of Ta2O5 within this range, the high refractive index glass 100 can achieve a high refractive index while maintaining a high transmittance to visible light, while maintaining the stability and low cost of the glass. Adding an appropriate amount of WO3 can increase the refractive index of the optical glass. In optical glasses of different types and compositions, the degree of influence of WO3 on the refractive index may vary greatly. By containing WO3, the transmittance may be reduced, and the mass production cost will increase significantly. Therefore, WO3 is an optional component. The content of WO3 in the high refractive index glass is preferably less than 1.0%, which can increase the refractive index of the glass while ensuring the transmittance and cost of the glass. ZnO is a component that can improve the mechanical properties of glass, such as strength and crack resistance. If the ZnO content is too much, the glass becomes easily devitrified, and if the content is too low, it cannot achieve the effect of improving the strength of the glass. Therefore, the ZnO content in the high refractive index glass is preferably greater than 0.5%, which can maintain the stability and mechanical properties of the glass. The ZnO content is less than 16.5% to ensure that it becomes a high refractive index glass. Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3), Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3) in the high refractive index glass is preferably greater than 0.3, which can ensure the high refractive index of the glass, while Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3) is less than 0.75 to ensure high transmittance, stability, excellent mechanical properties and low cost. It should be noted that the content here refers to the mol% based on the oxide.The above ingredients mainly improve the refractive index of the glass while ensuring that the glass has higher transmittance, mechanical properties, mass production cost, etc., so that the mass production cost and performance ratio is maximized while further improving the refractive index and transmittance of the glass.

[0021] During the manufacturing process of high refractive index glass, unavoidable impurities are allowed, including SiO2 or Al2O3 introduced by crucibles, refractory materials, etc. during the manufacturing process. In this case, in order to ensure the refractive index and transmittance of the high refractive index glass, the total content of SiO2 and Al2O3 in the glass is specified to be less than 3.0%.

[0022] It also includes Pb. The Pb element significantly increases the refractive index of the glass, but it does not meet environmental protection requirements. Therefore, it can be introduced in trace amounts as an impurity. The total content of Pb in high-refractive index glass is less than 500ppm.

[0023] To further optimize the performance and cost ratio of batch products, based on the molar percentage of oxides, the content of Bi2O3 is 25mol% to 32mol%, the content of Nb2O5 is 4.7mol% to 8.7mol%, the content of TeO2 is 23.5mol% to 29mol%, the content of P2O5 is 8mol% to 12.5mol%, the content of B2O3 is 15.3mol% to 31mol%, the content of TiO2 is 0mol% to 0.1mol%, the content of Ta2O5 is 0mol% to 0.1mol%, the content of WO3 is 0mol% to 0.1mol%, and the content of ZnO is 4.5mol% to 10.5mol%; 40≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤55. According to the test, the refractive index of the high refractive index glass is 2.09-2.35 when the thickness is 10mm, which is smaller than the wavelength λ of 450nm. 70 The transmittance is 82.4% to 96.8%, and the wavelength λ 70 It is the wavelength that shows an external transmittance of 70% when the thickness is 10 mm.

[0024] The present invention also provides a method for preparing the high refractive index glass as described above, wherein the method comprises mixing raw materials according to components and performing a melting treatment to obtain molten glass liquid; and shaping the molten glass liquid by pouring, molding, rolling, float method, etc. to obtain the high refractive index glass.

[0025] During the melting process, the container material for melting the glass is Pt or Pt alloy, which can effectively avoid the introduction of impurities. During the melting process, water vapor is added to the molten atmosphere or a gas containing water vapor is filled into the melt for bubbling treatment to increase the moisture content of the molten glass. This can effectively improve the transmittance and clarity of the glass. The preparation method is simple, low-cost, and does not require modification of existing equipment.

[0026] As mentioned above, high refractive index glass is used in the preparation of head-mounted displays. Wearable devices can be prepared, such as light guides, filters, lenses, etc. used in glasses with projectors, glasses-type, goggle-type displays, virtual reality augmented reality display devices, virtual image display devices, etc.; lenses, protective glass, etc. used in vehicle-mounted cameras and robot visual sensors. Even in vehicle-mounted cameras that are exposed to harsh environments, it can be used appropriately. It can also be used for glass substrates for organic EL displays, wafer-level lens array substrates, lens unit substrates, lens formation substrates using etching methods, optical waveguides, etc., with better light transmittance and refractive index, thereby improving customer experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a sample of a high refractive index glass of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0029] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0030] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0031] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0032] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0033] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0034] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0035] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0036] The present invention discloses a high refractive index glass, comprising the following components: a transition metal and an oxide; the transition metal is introduced as an impurity, and the transition metal is less than 4 ppm by mass, preferably, the transition metal is less than 1 ppm; the transition metal comprises one or more of Fe, Cr, Ni, Cu, Mn, Co and V;

[0037] In terms of molar percentage based on oxides, the oxides include: 17mol% to 49mol% Bi2O3, 2.7mol% to 15.7mol% Nb2O5, 8.5mol% to 39mol% TeO2, 2mol% to 19.5mol% P2O5, 11.3mol% to 41mol% B2O3, 0mol% to 1mol% TiO2, 0mol% to 1mol% Ta2O5, 0mol% to 1mol% WO3 and 0.5mol% to 16.5mol% ZnO, 30≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤75.

[0038] Preferably, it also includes impurities and Pb, and on a mass basis, Pb is less than 500ppm, more preferably, less than Pb<100ppm, and further, Pb<10ppm; the impurities include SiO2 and / or Al2O3, and on a molar percentage basis based on the oxide, the impurities are less than 3%, and more preferably, the impurities are less than 1%.

[0039] More preferably, in terms of molar percentage based on the oxide, the content of Bi2O3 is 25mol% to 32mol%, the content of Nb2O5 is 4.7mol% to 8.7mol%, the content of TeO2 is 23.5mol% to 29mol%, the content of P2O5 is 8mol% to 12.5mol%, the content of B2O3 is 15.3mol% to 31mol%, the content of TiO2 is 0mol% to 0.1mol%, the content of Ta2O5 is 0mol% to 0.1mol%, the content of WO3 is 0mol% to 0.1mol%, and the content of ZnO is 4.5mol% to 10.5mol%; 50mol%≤(TeO2+TiO2+WO3+Nb2O5+Bi2O3); 40≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤55.

[0040] To further illustrate the present invention, the present invention provides 50 embodiments and tests its performance. The components of each embodiment and the corresponding product performance are shown in the following table: Note: The impurity content of the raw materials in the table refers to the content of the components other than the components of the raw materials shown. In the table, "less" means less than 3ppm of the whole raw material, and "more" means more than 3ppm of the whole raw material. "Te+Ti+W+Nb+Bi" refers to the total molar content of TeO2, TiO2, WO3, Nb2O5 and Bi2O3 in each glass. "Bi / (Te+Ti+W+Nb+Bi)×100" refers to the molar percentage obtained by multiplying the ratio of the molar content of oxide Bi2O3 to the total molar content of oxide TeO2, TiO2, WO3, Nb2O5 and Bi2O3 by 100. The "Fe, Cr, Ni content" in the table refers to the total content of Fe, Cr and Ni in each embodiment glass. The content of Fe, Cr and Ni is determined by ICP mass spectrometry.

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] The products in the examples are tested in the following manner:

[0049] Wavelength 70 : When the plate thickness is 10 mm, the wavelength at which the external transmittance is 70% is set to λ 70 That is, the wavelength λ 70 The wavelength of light with an external transmittance of 70% for a sample with a thickness of 10 mm. The wavelength λ of the high refractive index glass 100 70 It is preferably less than 450nm, more preferably less than 450nm, further preferably less than 440nm, and further preferably less than 435nm. 70 In this range, high transmittance of visible light can be achieved. 70 The external transmittance can be measured by using a spectrophotometer on a sample with a double-sided mirror surface polished to a thickness of 10 mm. The sample structure is shown in Figure 1 .

[0050] Light transmittance: When the thickness of high refractive index glass is 10mm, the internal transmittance of light with a wavelength of 450nm is within this range, which can achieve high transmittance for visible light. The internal transmittance of glass with a thickness of 10mm can be calculated by the measured values ​​of two external transmittances with different plate thicknesses and the following formula:

[0051]

[0052] It should be noted that the external transmittance refers to the transmittance including the surface reflection loss. In the formula, X is the internal transmittance of the glass with a thickness of 10 mm, T1 and T2 are the external transmittance, and Δd is the thickness difference of the sample.

[0053] As can be seen from the table above, when the thickness is 10mm, its refractive index is 2.09~2.35, which is smaller than the wavelength λ of 450nm. 70 The transmittance is 82.4% to 96.8%, and the wavelength λ 70 It is the wavelength that shows an external transmittance of 70% when the thickness is 10 mm.

[0054] The method for preparing the high refractive index glass as described above comprises:

[0055] The raw materials are mixed according to the components and melted to obtain molten glass liquid. Specifically, the raw materials are mixed according to the components, placed in a platinum crucible and heated to 950°C for 2 hours to obtain molten glass liquid. During the melting process, the container material for melting the glass is Pt or Pt alloy. During the melting process, water vapor is added to the melting atmosphere or a gas containing water vapor is filled into the melt for bubbling treatment to increase the moisture content of the molten glass liquid.

[0056] The molten glass is formed and annealed to obtain high refractive index glass, specifically:

[0057] Then, the molten glass is cast into a 60mm×55mm×30mm graphite mold or a silicon carbide mold. Preheating the mold before casting can improve the casting quality. In this embodiment, the mold is preheated to 500°C. Subsequently, the glass is moved into an annealing furnace preheated to 480°C and kept warm for 40 minutes, and then cooled to room temperature at a cooling rate of 1°C / min to obtain a glass sample. Subsequently, a single-wire cutting machine and a multi-wire cutting machine are used to cut the glass block into 25.5mm×25.5mm, 10.5mm and 1.5mm thick samples, and a grinder and a polisher are used to adjust the plate thickness and polish the surface to prepare a glass plate with a length and width of 25mm×25mm and a plate thickness of 10mm and 1mm.

[0058] It should be noted that the products obtained in the above embodiments are all prepared in this way, but the preparation method of the glass is not limited thereto and can be prepared using known methods such as molding, float method, overflow method, slit down-draw method and roller pressing method, which will not be described in detail here.

[0059] The present invention also provides the use of the high refractive index glass as described above in the preparation of a head mounted display.

[0060] The high refractive index glass provided by the present invention is preferably a glass plate having a thickness of 0.01 mm or more and 2.0 mm or less as an optical glass. The thickness is more preferably 0.1 mm or more, which can suppress the warping caused by the self-weight of the high refractive index glass 100. On the other hand, if the thickness is 2.0 mm or less, preferably 1.5 mm or less, and more preferably 1.0 mm or less, the weight of an optical element using the high refractive index glass can be reduced.

[0061] When the high refractive index glass is a plate, the area of ​​the main surface is preferably 9 cm 2 If the area is 9cm 2 More than that, multiple optical elements can be configured to improve productivity. The plate area is more preferably 30cm 2 More preferably, 300 cm 2 More than 1000cm 2 above.

[0062] When the high refractive index glass is used as a glass plate, the 25 cm of the main surface 2 The local thickness variation (LTV) in the region is preferably less than 2 μm. By having a flatness in this range, a nanostructure of a desired shape can be formed on the main surface using an imprinting technique, etc., and the desired light-guiding properties can be obtained. In particular, in the light guide, ghosting and distortion caused by differences in optical path lengths can be prevented. The LTV is more preferably less than 1.5 μm, and particularly preferably less than 0.5 μm.

[0063] When the high refractive index glass is made into a circular glass plate with a diameter of 8 inches, the warping is preferably 50 μm or less. If the warping of the high refractive index glass 100 is 50 μm or less, a nanostructure of a desired shape can be formed on the main surface using an imprinting technique or the like, and the desired light-guiding properties can be obtained. When a plurality of light guides are desired, light guides with stable quality can be obtained. The warping of the high refractive index glass 100 is more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 20 μm or less.

[0064] When the high refractive index glass is made into a circular glass plate with a diameter of 6 inches, the warping is preferably 30 μm or less. If the warping of the high refractive index glass 100 is 30 μm or less, a nanostructure of a desired shape can be formed on the main surface using an imprinting technique or the like, and the desired light-guiding properties can be obtained. When a plurality of light guides are desired, light guides with stable quality can be obtained. The warping of the high refractive index glass 100 is more preferably 20 μm or less, further preferably 15 μm or less, and particularly preferably 10 μm or less.

[0065] When the high refractive index glass is made into a square glass plate with each side being 6 inches, the warping is preferably less than 100 μm. If the warping of the high refractive index glass 100 is less than 100 μm, a nanostructure of a desired shape can be formed on the main surface using an imprinting technique or the like, and the desired light-guiding properties can be obtained. When a plurality of light guides are desired, light guides with stable quality can be obtained. The warping of the high refractive index glass 100 is more preferably less than 70 μm, further preferably less than 50 μm, further preferably less than 35 μm, and particularly preferably less than 20 μm.

[0066] In addition, in the high refractive index glass prepared in the above embodiment, the surface roughness Ra of the main surface is preferably less than 2nm. By having Ra in this range, it is possible to form a nanostructure of the desired shape on the main surface using techniques such as imprinting, thereby obtaining the desired light-guiding properties. In particular, in the light guide, diffuse reflection at the interface can be suppressed to prevent ghosting and distortion. The Ra is more preferably less than 1.5nm, and further preferably less than 1nm. Here, the surface roughness Ra is the arithmetic mean roughness. In the embodiment, the surface roughness Ra value of an area of ​​10μm×10μm is measured using an atomic force microscope (AFM).

[0067] This high refractive index glass has a high refractive index and high transmittance, so it is more suitable for use as a light guide plate, used in wearable devices, such as light guides, filters, lenses, etc. used in glasses with projectors, glasses-type, goggle-type displays, virtual reality augmented reality display devices, virtual image display devices, etc.; used in vehicle-mounted cameras, lenses, protective glass, etc. used in robot visual sensors. It can be used appropriately even in harsh environments such as vehicle-mounted cameras. It can also be used for glass substrates for organic EL, substrates for wafer-level lens arrays, substrates for lens units, lens formation substrates using etching methods, optical waveguides, etc. In addition, optical components with an anti-reflection film formed on the main surface of the high refractive index glass are also suitable for wearable devices, vehicle-mounted uses, and robot-mounted uses. The anti-reflection film includes a dielectric multilayer film of 4 or more layers and 10 or less layers obtained by alternately stacking low refractive index films such as SiO2 and high refractive index films such as TiO2.

[0068] In summary, the high refractive index glass of the present invention has a high refractive index and a high transmittance, and has good manufacturing characteristics, and is suitable as an optical glass for wearable devices, vehicles, and robots.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A high refractive index glass, characterized in that: The invention comprises the following components: a transition metal and an oxide; the transition metal is less than 4 ppm by mass, and the transition metal comprises one or more of Fe, Cr, Ni, Cu, Mn, Co and V; In terms of molar percentage based on oxides, the oxides include: 17mol% to 49mol% Bi2O3, 2.7mol% to 15.7mol% Nb2O5, 8.5mol% to 39mol% TeO2, 2mol% to 19.5mol% P2O5, 11.3mol% to 41mol% B2O3, 0mol% to 1mol% TiO2, 0mol% to 1mol% Ta2O5, 0mol% to 1mol% WO3 and 0.5mol% to 16.5mol% ZnO, 30≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤75.

2. The high refractive index glass according to claim 1, characterized in that: It also includes Pb, which is less than 500 ppm by mass.

3. The high refractive index glass according to claim 1, characterized in that: It also includes impurities, including SiO2 and / or Al2O3, and the impurities are less than 3% in molar percentage based on the oxide.

4. The high refractive index glass according to claim 1, characterized in that: In terms of molar percentage based on the oxide, the content of Bi2O3 is 25mol% to 32mol%, the content of Nb2O5 is 4.7mol% to 8.7mol%, the content of TeO2 is 23.5mol% to 29mol%, the content of P2O5 is 8mol% to 12.5mol%, the content of B2O3 is 15.3mol% to 31mol%, the content of TiO2 is 0mol% to 0.1mol%, the content of Ta2O5 is 0mol% to 0.1mol%, the content of WO3 is 0mol% to 0.1mol%, and the content of ZnO is 4.5mol% to 10.5mol%.

5. The high refractive index glass according to claim 1, characterized in that: In terms of molar percentage based on oxides, 50 mol% ≤ (TeO2+TiO2+WO3+Nb2O5+Bi2O3).

6. The high refractive index glass according to claim 1, characterized in that: In terms of molar percentage based on oxides, 40≤Bi2O3 / (TeO2+TiO2+WO3+Nb2O5+Bi2O3)×100≤55.

7. The high refractive index glass according to any one of claims 1 to 6, characterized in that: When the thickness is 10mm, its refractive index is 2.09~2.35, which is smaller than the wavelength λ of 450nm. 70 The transmittance is 82.4% to 96.8%, and the wavelength λ 70 It is the wavelength that shows an external transmittance of 70% when the thickness is 10 mm.

8. The method for preparing the high refractive index glass according to any one of claims 1 to 7, characterized in that: include: Mixing raw materials according to components and melting them to obtain molten glass; The molten glass is shaped and annealed to obtain high refractive index glass.

9. The method for preparing high refractive index glass according to claim 8, characterized in that: During the melting process, the container material for melting the glass is Pt or Pt alloy. During the melting process, water vapor is added to the molten atmosphere or a gas containing water vapor is filled into the melt for bubbling treatment to increase the moisture content of the molten glass.

10. Use of the high refractive index glass according to any one of claims 1 to 7 in preparing a head mounted display.

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