Optical glass, preparation method thereof and light guide plate

Abstract

The invention provides optical glass, a preparation method thereof and a light guide plate. The optical glass comprises a glass matrix, and the glass matrix comprises the following components in terms of 100% of the total mass of the glass matrix: 0.5%-8.0% of B; 0.5%-6% of Si; 30% to 55% of La; 0.5%-12% of Y; ti: 3.1% to 10.5%; 0.9% to 9.5% of Nb; 0%-4.5% of Zn; 0.9% to 8.4% of Zr; 18.7% to 31.5% of O; the refractive index of the optical glass is 2.00 to 2.03, and the abbe number of the optical glass is 27 to 33. The optical glass has the advantages of high refractive index, low density, appropriate relative grinding hardness and Knoop hardness, and high internal transmittance.

Description

Technical Field

[0001] This invention relates to an optical glass, its preparation method, and a light guide plate, belonging to the field of optical glass. Background Technology

[0002] Optical glass is widely used as a light guide plate in projector glasses, eyeglass-type or goggle-type displays, virtual reality (VR) or augmented reality (AR) display devices, and virtual image display devices. Through this light guide plate, one can see not only the external scenery but also the image displayed on the glass. Furthermore, 3D displays can be achieved by projecting different images onto the left and right sides of the glasses, or virtual reality spaces can be realized by utilizing the technology of combining the lens and retina of the eye. For optical glass used in wearable devices, to provide a better user experience and increase the device's lifespan, it must possess a high refractive index while also having low density, high mechanical strength, and excellent chemical resistance.

[0003] Patent application CN114341069 A discloses an optical glass plate for use as a light guide plate in wearable image display devices. The glass composition contains at least one selected from Nb₂O₅, La₂O₃, and Gd₂O₃, has a refractive index nd of 1.90 to 2.30, and an internal transmittance τ at a wavelength of 450 nm at a thickness of 10 mm. 450 The internal transmittance τ at a wavelength of 520nm is above 75% and at a thickness of 10mm. 520 With a transmittance of over 85%, its internal transmittance is not high enough, resulting in insufficient brightness of the image seen by the user.

[0004] Patent application CN116062988 A discloses an optical glass, its preparation method, and a glass article for display. The optical glass has a refractive index (nd) ranging from 1.85 to 2.0 and a density less than or equal to 4.7 g / cm³. 3 The optimal optical glass has a visible light transmittance greater than 88% and a Vickers hardness greater than or equal to 660 kgf / mm². 2 Its composition contains 5.0wt% to 40.0wt% BaO. During the melting process of glass raw materials, it increases the erosion of Pt in the melting equipment, making it difficult to melt glass with excellent internal quality and hindering the reduction of glass production costs.

[0005] Patent application CN116002970 A discloses an optical glass with a high refractive index, low specific gravity relative to refractive index, high devitrification resistance, and low cost. Its refractive index (nd) is 1.95~2.15, and its Abbe number (υd) is 20.00~30.00, containing 20.0%~40.0% TiO2 by mass percentage. The high content of titanium, combined with low-valence coloring impurities, forms complexes that absorb light in the short-wavelength region of the spectrum, affecting transmittance. Furthermore, the valence band electrons of titanium gain energy and transition to the conduction band, forming electron-hole pairs. This causes ion displacement within the glass, altering the material's band structure and consequently changing its visible light absorption characteristics, which is detrimental to improving the glass's transmittance.

[0006] Patent application CN118724456 A discloses an optical glass with a high refractive index and suppressed surface devitrification, relating to optical glass, optical elements, light guide plates, and image display devices. It contains SiO2, B2O3, TiO2, Nb2O5, Y2O3, La2O3, and Gd2O3 as essential components. The introduction of Gd2O3 increases the glass's specific gravity and raw material costs.

[0007] The refractive index of optical glass is directly and decisively related to its chemical composition and internal microstructure. The refractive index of glass is primarily determined by the ionic polarizability of its constituent elements. Generally, the higher the content of elements with high polarizability, the higher the refractive index of the glass. Elements with high polarizability typically have large atomic weights, loose electron clouds, and are easily polarized by external electric fields. As the content of elements with high polarizability increases, the specific gravity of the glass also increases, and the transmission properties in the high-frequency visible light wavelength range (e.g., in the blue light range of 420 nm to 490 nm, especially at 420 nm, 450 nm, or 460 nm) are often unsatisfactory.

[0008] As the liquidus temperature of glass increases—the temperature at which the melt and solid or crystal are in equilibrium—its short-wavelength transmittance decreases. Below the liquidus temperature, crystals precipitate from the melt. High-refractive-index glasses, containing fewer glass forgings and having lower viscosity, exhibit weaker or no inhibition of crystallization kinetics, and thus crystallize very rapidly below the liquidus temperature. Therefore, a high liquidus temperature is accompanied by a high melting temperature. A high melting temperature increases the platinum content fused into the high-temperature glass melt during glassmaking. The scattering and absorption of light in the 380–400 nm wavelength range by Pt particles reduces the glass's short-wavelength transmittance.

[0009] Furthermore, higher temperatures may cause a partial reduction in the polyvalent glass components (especially niobium and titanium) and their respective lower oxidation levels, resulting in undesirable coloration in the glass and reduced transmittance. High liquidus temperatures also increase the energy consumption in glass production, leading to higher manufacturing costs.

[0010] Therefore, researching an optical glass with high refractive index, excellent crystallization performance, and high transmittance has become an urgent technical problem to be solved. Summary of the Invention

[0011] The problem the invention aims to solve

[0012] In view of the technical problems existing in the prior art, the present invention first provides an optical glass with a refractive index (nd) of 2.00~2.03 and an Abbe number (υd) of 27~33. The optical glass of the present invention has low density, suitable relative grinding hardness and Knoop hardness, and high internal transmittance.

[0013] Furthermore, the present invention also provides a method for preparing optical glass, which is simple and easy to implement, uses readily available raw materials, and is suitable for mass production.

[0014] Solution for solving the problem

[0015] This invention provides an optical glass, wherein the optical glass comprises a glass matrix, and the glass matrix comprises the following components, based on 100% of the total mass of the glass matrix:

[0016] B: 0.5%~8.0%, preferably 1.0%~7.0%;

[0017] Si: 0.5%~6%, preferably 1%~6%;

[0018] La: 30%~55%, preferably 32%~53%;

[0019] Y: 0.5%~12%, preferably 1.0%~10%;

[0020] Ti: 3.1%~10.5%, preferably 4.2%~9.9%;

[0021] Nb: 0.9%~9.5%, preferably 1.5%~8.9%;

[0022] Zn: 0%~4.5%, preferably 0%~3.0%;

[0023] Zr: 0.9%~8.4%, preferably 1.7%~7.3%;

[0024] O: 18.7%~31.5%, preferably 19.9%~30.8%;

[0025] The optical glass has a refractive index of 2.00 to 2.03 and an Abbe number of 27 to 33.

[0026] According to the optical glass of the present invention, the content of La and Y elements, ∑(La+Y), is 32%~65%, preferably 34%~60%, based on the total mass of the glass matrix as 100%.

[0027] The sum of the contents of Si and B elements, ∑(Si+B), is 4.8%~10%; preferably 5.0%~9%.

[0028] According to the optical glass of the present invention, the ratio of Ti to Nb, based on the total mass of the glass matrix as 100%, is 0.5 to 3.5, preferably 1.0 to 3.0.

[0029] According to the optical glass of the present invention, the ratio of O element content to the sum of the mass of Ti and Nb elements, O / (Ti+Nb), is 1 to 4, preferably 1.2 to 3, based on the total mass of the glass matrix as 100%.

[0030] The optical glass according to the present invention further comprises additive components; preferably, the additive components include Li and / or F elements.

[0031] According to the optical glass of the present invention, the Li element content is not more than 2000 ppm, preferably not more than 1500 ppm, based on the total mass of the glass matrix as 100%; and the F element content is not more than 1000 ppm, preferably not more than 900 ppm.

[0032] According to the optical glass of the present invention, the optical glass does not contain one or more of Ba, Bi, Ge, Ta, Gd, Yb, W and Te.

[0033] According to the optical glass of the present invention, the optical glass has one of the following characteristics:

[0034] The density of the optical glass is 4.98 g / cm³. 3 the following;

[0035] The crystallization temperature of the optical glass is below 1160℃;

[0036] The wavelength λ of the optical glass when its external transmittance is 70% 70 Below 410nm, the wavelength λ5 is below 370nm when the external transmittance is 5%;

[0037] The internal transmittance τ of the 10mm thick optical glass at a wavelength of 460nm 10 It is over 96%;

[0038] The relative grinding hardness FA of the optical glass is 100~150;

[0039] The Knoop hardness HK of the optical glass is 600 GPa to 750 GPa.

[0040] The present invention also provides a method for preparing optical glass according to the present invention, wherein the raw materials of each component of the optical glass are weighed in proportion, mixed evenly and then melted, and then poured or poured into a molding die, or directly pressed into shape.

[0041] The present invention also provides a light guide plate comprising the optical glass described in the present invention.

[0042] The effects of the invention

[0043] The optical glass of this invention has a high refractive index, low density, suitable relative grinding hardness and Knoop hardness, and high internal transmittance.

[0044] Furthermore, the method for preparing the optical glass of the present invention is simple and easy to implement, the raw materials are readily available, and it is suitable for mass production. Detailed Implementation

[0045] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0046] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0047] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0048] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0049] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0050] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0051] In this invention, the optical glass comprises a glass matrix. Elements are introduced in various forms using compounds capable of incorporating their respective amounts. In the following description, the content of each element is expressed as a mass percentage of the glass matrix.

[0052] Boron (B) is the main structural component in the glass network framework and also acts as a flux to lower the glass melting temperature. Boron is structurally composed of boron-oxygen trigonal [BO3] and boron-oxygen tetrahedron [BO4]. Under different conditions, boron can exist as trigonal [BO3] or boron-oxygen tetrahedron [BO4]. At high-temperature melting conditions, it is generally difficult to form boron-oxygen tetrahedra, and it can only exist as trigonal structures. However, at low temperatures, under certain conditions, boron tends to capture free oxygen to form tetrahedra, resulting in a denser structure and increasing the low-temperature viscosity of the glass. Because boron has the property of lowering glass viscosity at high temperatures and increasing it at low temperatures, it is also a major component in reducing the glass's refractive index. When the boron content is too low, it cannot act as a flux and will reduce the chemical stability of the glass; while when the boron content is too high, it will reduce the glass's refractive index and increase its tendency to crystallize. Therefore, based on the total mass of the glass matrix as 100%, the content of element B is 0.5% to 8.0%, preferably 1.0% to 7.0%, and more preferably 1.5% to 4.5%.

[0053] Si, the element that forms the main structure of the glass network framework, is an effective component that promotes the formation of stable glass and improves its viscosity, anti-crystallization properties, and chemical stability. If the Si content is too low, it will not play its due role; if the Si content is too high, it will cause the glass to melt poorly and the crystallization temperature to rise. Therefore, based on the total mass of the glass matrix as 100%, the Si content is 0.5% to 6%, preferably 1% to 6%, and more preferably 1.5% to 4.5%.

[0054] Through extensive experimentation, the inventors discovered that in the optical glass of this invention, the sum of the contents of Si and B elements, ∑(Si+B), has a decisive influence on the glass's formation characteristics. If the sum of the contents of Si and B elements, ∑(Si+B), is too low, a stable glass cannot be formed; if the sum of the contents of Si and B elements, ∑(Si+B), is too high, the refractive index and Abbe number of the obtained glass are difficult to reach the specific ranges of this invention. Therefore, in this invention, based on the total mass of the glass matrix as 100%, the sum of the contents of Si and B elements, ∑(Si+B), is 4.8% to 10%; preferably 5.0% to 9%, for example, 5.2% to 8%, etc.

[0055] La (La) is an effective component for increasing the refractive index and reducing dispersion in glass, and is a major component of this type of high-refractive-index optical glass. When the La content is too low, the refractive index and Abbe number of the glass will be difficult to reach the aforementioned specific ranges; when the La content is too high, the glass's devitrification tendency increases, the liquidus temperature rises, and the specific gravity of the glass becomes too high. In this invention, based on the total mass of the glass matrix as 100%, the percentage content of La is 30% to 55%, preferably 32% to 53%, and more preferably 35% to 50%.

[0056] In this invention, the properties of Y and La are essentially the same, which can give the optical glass a high refractive index and low dispersion. Appropriate addition to the Y element can improve the crystallization properties of the glass and reduce its specific gravity. However, when the Y content is too low, the devitrification resistance deteriorates and the effect of reducing specific gravity is not significant; when the Y content is too high, it is actually detrimental to improving the glass's refractive index. In this invention, based on the total mass of the glass matrix as 100%, the percentage content of Y element is 0.5%~12%, preferably 1.0%~10%, and more preferably 1.5%~9.0%.

[0057] Through extensive experimentation, the inventors discovered that the sum of the contents of La and Y elements, ∑(La+Y), in the optical glass of this invention has a certain impact on the performance of the optical glass. If ∑(La+Y) is too high by mass percentage, the performance of the manufactured optical glass will not meet expectations, and the specific gravity of the glass will be too high. However, if ∑(La+Y) is too low, the optical constants of the glass will be difficult to reach the required range. Therefore, based on the total mass of the glass matrix as 100%, the sum of the contents of La and Y elements, ∑(La+Y), is 32%~65%, preferably 34%~60%, and more preferably 38%~55%.

[0058] Ti is an essential component for obtaining the optical glass of this invention, and within a suitable range, it helps improve the crystallization properties of the glass. If the Ti content is too low, it is difficult to obtain the required optical constants; if the Ti content is too high, the crystallization properties of the glass deteriorate, and the glass color deepens. Therefore, in this invention, based on the total mass of the glass matrix as 100%, the mass percentage content of Ti is 3.1% to 10.5%, preferably 4.2% to 9.9%, and more preferably 4.9% to 9.5%.

[0059] Nitrogen (Nb) element plays a role in increasing the refractive index, improving chemical stability, and enhancing crystallization properties of optical glass. In this invention, this effect is not significant when the Nb content is too low; conversely, when the Nb content is too high, the crystallization properties of the glass gradually deteriorate, making it difficult to achieve the optical performance expected in this invention. Therefore, in this invention, based on the total mass of the glass matrix as 100%, the Nb content is 0.9% to 9.5%, preferably 1.5% to 9.0%, and more preferably 1.9% to 8.2%.

[0060] The valence electron configuration of Ti is 3d. 2 4s 2 It can lose 4 valence electrons to form Ti 4+ It can also lose 3 valence electrons to form Ti. 3+ It can also lose 2 valence electrons to form Ti 2+ Ti with a +4 valence loses all its 3d orbital electrons, resulting in no dd electron transitions and a colorless color. Ti with +3 and +2 valences absorbs blue-green light during 3d orbital electron transitions, giving it a purplish-red appearance.

[0061] The valence electron configuration of Nb is 4d. 4 5s 1 Common oxidation states of Nb are +2, +3, +4, and +5, and different oxidation states will display different colors. Nb with a +5 oxidation state has lost all its 4d orbitals and there are no dd electron transitions, so it is usually white or colorless. Nb with +3 and +4 oxidation states has unfilled d orbitals, and dd electron transitions absorb visible light, resulting in dark colors such as black, blue, and red. In other words, the higher the oxidation state, the lighter the color.

[0062] Both Ti and Nb exhibit dd-electron transitions, absorbing visible light and reducing the transmittance of the glass. To achieve optimal transmittance, the ratio of Ti to Nb content needs to be controlled. If the Ti / Nb mass ratio is too low, it is difficult to obtain the optical constants of this invention, and the glass's crystallization temperature exceeds 1300℃, increasing the Pt content in the glass. Furthermore, Ti's electronegativity of 1.5 is lower than Nb's 1.6, which is detrimental to the absorption of Ti. 4+The formation of ions is detrimental to improving glass transmittance; a high Ti / Nb mass ratio strengthens the dd transition of Ti, which is also detrimental to improving glass transmittance. Therefore, in this invention, based on the total mass of the glass matrix as 100%, the Ti / Nb mass ratio is 0.5~3.5, preferably 1.0~3.0, and more preferably 1.2~2.5.

[0063] Zinc (Zn) is an effective component for improving the chemical stability, thermal stability, and refractive index of glass. Using zinc-oxygen octahedrons [ZnO6] as the network outer oxide, zinc-oxygen tetrahedra [ZnO4] can also be formed and enter the glass's structural network, making the glass structure more stable. If the Zn content is too high, the desired effect cannot be achieved. Therefore, in this invention, based on the total mass of the glass matrix as 100%, the Zn content is 0%~4.5%, preferably 0%~3.0%, and more preferably 0%~2.0%.

[0064] Zr possesses high refractive index and low dispersion properties. Introducing it into glass can improve its chemical stability and increase its refractive index. When glass contains a large amount of rare earth elements, introducing a certain amount of Zr can reduce its crystallization tendency. However, when the Zr content is too high, it will increase the crystallization temperature and rate, and worsen the glass's resistance to crystallization. Furthermore, Zr has a small ionic radius, high charge, and strong ionic field; when the Zr content is too high, it can cause anion accumulation, potentially leading to phase separation in the glass. Conversely, when the Zr content is too low, it does not have the desired effect. Therefore, in this invention, based on the total mass of the glass matrix (100%), the Zr content is 0.9% to 8.4%, preferably 1.7% to 7.3%, and more preferably 2.5% to 6.2%.

[0065] Oxygen is the main structural element in the glass network framework. The atoms of Si and B, the main structural elements in the glass network framework, are located at the center of the glass network structure, surrounded by four or three O atoms, forming [SiO4] tetrahedra, [BO3] trigonometric prisms, or [BO4] tetrahedra. The oxygen atoms connecting two network formations (such as Si-O-Si) are called bridging oxygen atoms. Bridging oxygen atoms form the "skeleton" of a robust, continuous three-dimensional random network, determining the optical properties, mechanical strength, chemical stability, and high / low temperature viscosity of the glass. At the same time, oxygen also creates an environment for trace transition metal elements (such as Fe, Cr, Cu, Mn, etc.) in the glass to produce color, leading to glass coloration and reducing the glass's transmittance. In other words, O in glass is both a structural builder and a "regulatory valve" of optical performance, but also a "potential disruptor" that requires precise control. In this invention, the content of O element is 18.7% to 31.5% based on the total mass of the glass matrix as 100%, preferably 19.9% ​​to 30.8%, and more preferably 21.3% to 29.3%.

[0066] In this invention, the content of oxygen (O) directly determines the valence states of Ti and Nb in the glass. Specifically, the ratio of the O content to the total mass of Ti and Nb (O / (Ti+Nb)) directly determines the Ti content in the glass. 4+ and Nb 5+ The content of O is important. A higher O / (Ti+Nb) ratio results in fewer dd transitions in the glass, leading to a lighter color, but also a decrease in the glass's optical constants. Conversely, a lower O / (Ti+Nb) ratio results in more dd transitions in the glass, leading to a darker color and hindering the improvement of transmittance. In this invention, based on the total mass of the glass matrix as 100%, the O / (Ti+Nb) ratio is 1-4, preferably 1.2-3, and more preferably 1.5-2.5.

[0067] Furthermore, in this invention, the optical glass may also contain additive components; preferably, the additive components include Li and / or F elements.

[0068] Li is a glass network modifier that can disrupt the silicon-oxygen (Si-O-Si) network, significantly reducing the glass's melting temperature and melt viscosity. However, its addition leads to a decrease in refractive index, which is detrimental to the control of optical performance. Excessive Li content is also detrimental to achieving the optical properties of the optical glass of this invention. In this invention, based on the total mass of the glass matrix as 100%, the Li content does not exceed 2000 ppm, preferably not more than 1500 ppm, and more preferably not more than 1200 ppm, for example, 0 ppm to 2000 ppm.

[0069] Fire (F) has extremely high electronegativity. When it enters a SiO2-based network, it disrupts the continuous Si-O-Si bridging oxygen network, forming Si-F bonds and non-bridging oxygen, making the glass structure more "loose" and open, reducing the glass's specific gravity. Simultaneously, F can complex with trace amounts of transition metals such as Fe in the glass, reducing coloration and increasing transmittance. However, excessively high F content can increase the glass's crystallization tendency and decrease its refractive index. In this invention, based on the total mass of the glass matrix (100%), the F content does not exceed 1000 ppm, preferably not more than 900 ppm, and more preferably not more than 800 ppm, for example, 0 ppm to 1000 ppm.

[0070] Furthermore, in this invention, the density of the optical glass is 4.98 g / cm³. 3 The following conditions apply: the crystallization temperature of the optical glass is below 1160°C; the wavelength λ of the optical glass when its external transmittance is 70% 70 Below 410 nm, the wavelength λ5 with an external transmittance of 5% is below 370 nm; the internal transmittance τ of the 10 mm thick optical glass at a wavelength of 460 nm is... 10 (460nm) is above 96%; the relative grinding hardness FA of the optical glass is 100~150; the Knoop hardness HK of the optical glass is 600GPa~750GPa.

[0071] Furthermore, the optical glass of this invention may be free of Te, which easily causes volatile streaks, thus avoiding their formation; it may also be free of Ba, reducing corrosion of the melting equipment during glass production and lowering production costs; and it may be free of expensive elements such as Ge, Ta, Gd, and W. Additionally, to better achieve the objectives of this invention, it is emphasized that Yb, which has an absorption peak at 850 nm, is not introduced. Since Bi reacts with Pt at 1200℃~1250℃, increasing the difficulty of melting the glass and hindering the production of glass with excellent internal quality, the optical glass of this invention does not contain Bi.

[0072] Furthermore, to ensure the spectral transmittance of the optical glass described in this invention, the optical glass provided by this invention does not artificially introduce any coloring elements other than the components mentioned above: V, Mo, Cr, Mn, Fe, Co, Ni, Cu, and Ag. Simultaneously, it does not artificially introduce compounds containing the following harmful elements: Th, Cd, Tl, Os, Be, Se, Pb, As, and Hg. Furthermore, this invention strictly controls the coloring impurities V, Mo, Cr, Mn, Fe, Co, Ni, and Cu in the raw materials, ensuring that the content of these coloring impurities in the raw materials is below 5 ppm.

[0073] The present invention also provides a method for preparing optical glass according to the present invention, comprising: weighing and mixing the raw materials of each component in proportion, melting them, and then pouring or casting them into a molding mold, or directly pressing them into shape.

[0074] Specifically, the preparation method includes the following steps: weighing and mixing the raw materials containing the elements required for the optical glass of the present invention according to a certain proportion to prepare a batch; adding the prepared batch into a melting device (e.g., a platinum crucible); melting the batch into molten glass at a temperature of 1300℃~1350℃; raising the temperature to 1350℃~1400℃ for homogenization and debubbling; and lowering the temperature to 1200℃~1250℃ to adjust the viscosity of the molten glass. The entire process takes about 4h~6h. Finally, the molten glass is poured or poured into a molding die, or directly pressed into shape, and then slowly cooled to obtain the optical glass.

[0075] The optical glass of this invention is suitable for processing into a light guide plate. This light guide plate can be used as a component of virtual image or wearable device image display equipment, such as glasses with projectors, eyeglass-type or goggle-type displays, virtual reality (VR) or augmented reality (AR), etc. Preferably, the light guide plate can be a sensor in a wearable image display device, performing the following functions: guiding light emitted from the image display element of the wearable image display device towards the user's pupil, increasing the effective field of view of the display device, reducing light power loss and color balance shift, and improving image contrast.

[0076] Example

[0077] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0078] Examples 1-24 and Comparative Examples 1-6

[0079] Examples 1-24 and Comparative Examples 1-6 used SiO2, H3BO3, La2O3 or LaF3, Y2O3, YF3, Nb2O5, TiO2, ZnO, ZrO2, LiF, Li2CO3, Li2SO4·H2O and other raw materials to introduce elements. The raw materials were weighed and mixed evenly according to the proportions in Table 1-5 to prepare a batch. The batch was put into a platinum crucible and melted into glass liquid at 1350℃ for 1.5h. Then, the temperature was raised to about 1400℃ for 0.5h to homogenize and remove bubbles for 3h. Finally, the temperature was lowered to 1250℃ for 0.5h to adjust the viscosity of the glass liquid. The glass liquid was then poured into a mold and slowly cooled to obtain optical glass.

[0080] Performance testing

[0081] 1. Refractive index n d Abbe number υ d

[0082] The refractive index n of the obtained optical glass was tested according to the test method in GB / T7962.1 "Test methods for colorless optical glass—Part 1: Refractive index and dispersion coefficient". d Abbe number υ d The determination of n listed in the table d υ d The data are for annealing at -4℃ / H.

[0083] 2. Transition temperature (Tg) of optical glass

[0084] The transition temperature (Tg) of the optical glass was tested using a TMA tester from PE Corporation, USA.

[0085] 3. Crystallization temperature L of optical glass T

[0086] The crystallization temperature L was determined using a GM-N16P gradient furnace from Motoyama Corporation of Japan. T The determination.

[0087] 4. λ 70 With λ5

[0088] A glass specimen with a thickness of 10±0.1 mm and mutually parallel planar surfaces, after optical polishing, is prepared. An incident light of intensity I is then injected into the glass specimen from a direction perpendicular to these planar surfaces. in The intensity I of the transmitted light is measured. out The strength is greater than I out / I in This is called the external transmittance of the glass.

[0089] In the wavelength range of 200~700nm, the wavelength corresponding to an external transmittance of 70% is denoted as λ. 70The wavelength corresponding to an external transmittance of 5% is denoted as λ5.

[0090] 5. Internal transmittance τ at 460nm 10（460nm） :

[0091] The internal transmittance is the transmittance excluding surface reflection loss of the sample. It was measured using a Hitachi UH4150 UV-VIS-NIR spectrophotometer on samples with thicknesses of 10 mm and 50 mm, exhibiting bubble level 1 and streaking level B, and calculated using the following formula:

[0092]

[0093] In the formula: τ 10 —Internal transmittance of a 10mm sample; T 10 T 50 —Transmittance (including surface loss) of samples with a thickness of 10 mm and 50 mm.

[0094] 6. Density (ρ) of optical glass

[0095] The measurement shall be performed in accordance with the method specified in GB / T7962.20 "Test methods for colorless optical glass—Part 20: density".

[0096] 7. Relative abrasive hardness (FA)

[0097] Relative abrasive hardness refers to the abrasive hardness of the tested glass relative to standard glass H-K9 under the same abrasive conditions. The relative abrasive hardness FA of the tested glass is calculated by multiplying the volumetric abrasive amount of the glass sample by the volumetric abrasive amount of the tested standard glass H-K9 sample by 100.

[0098] The specific test method for the volumetric grinding amount of the glass sample and the standard glass H-K9 sample is as follows: The glass sample and the standard glass H-K9 sample of the same size are fixed on a specific type of cast iron grinding disc using a clamp. A pressure of 1 kg is applied to both the sample and the standard sample. Then, a suspension of No. 40 corundum and water in a fixed ratio is added. The grinding disc is rotated at a speed of 60 rpm to 65 rpm to grind the sample for 3 minutes. After grinding, the weight loss of the standard sample and the sample is measured and then converted into volumetric grinding amount.

[0099] 8. Knuth Hardness HK

[0100] The measurement shall be performed in accordance with the method specified in GB / T7962.18 "Test methods for colorless optical glass—Part 18: Kelvin hardness".

[0101] 9. Water resistance stability of powder coating (D) W

[0102] 10g±0.0001g of powdered glass with a particle size of 425-560μm (passed through a 40-32 mesh sieve) was placed in a filter and immersed in a quartz glass flask containing 80mL of distilled water (pH=6.5-7.5). The flask was kept at a constant temperature of 98-100℃ for 60 minutes. All the glass particles were then transferred to a filter that had reached constant weight. The filter was washed with 80mL of anhydrous ethanol and dried at 120±5℃ until constant weight was achieved.

[0103] According to the formula: Calculate the percentage of glass leaching.

[0104] In the formula: D W —Percentage of glass leaching (%); B—Mass of filter and sample (in g); C—Mass of filter and etched sample (in g); A—Mass of filter (in g).

[0105] Based on the percentage of water leaching by mass, the water resistance stability D of optical glass is determined. W Classify according to Table a below.

[0106] Table a

[0107]

[0108] 10. Powder method acid resistance stability DA

[0109] With D W The determination method is similar, involving the addition of a 0.01 mol / L nitric acid aqueous solution to the flask for treatment.

[0110] According to the formula: Calculate the percentage of glass leaching.

[0111] Where: D A —Percentage of glass leaching (%); B—Mass of filter and sample (in g); C—Mass of filter and etched sample (in g); A—Mass of filter (in g).

[0112] Based on the percentage of leaching by mass, the acid resistance stability D of optical glass is determined. A Classify according to Table b below.

[0113] Table b

[0114]

[0115] 11. Surface method resistance to humid atmosphere stability R C (S)

[0116] Under conditions of 50℃ and 85% relative humidity, the stability of optical glass against humid atmospheres is divided into three levels based on the time required for hydrolysis spots to form on the polished glass surface, as shown in Table c.

[0117] Table c

[0118]

[0119] 10. Surface method acid resistance stability R A (S)

[0120] Under the action of acetic acid solution at 0.1N (pH=2.9) and 50℃, the acid resistance stability of optical glass is divided into three levels according to the time required for interference colors to appear on the polished glass surface, or for the surface to show discoloration or peeling, as shown in Table d.

[0121] Table d

[0122]

[0123] 12. Surface method alkali resistance stability R OH (S)

[0124] A 40mm × 40mm × 5mm sample, polished on all six sides, was immersed in a 0.01mol / L sodium hydroxide aqueous solution at a constant temperature of 50℃ ± 3℃ for 15 hours with thorough stirring. The leaching mass per unit area was calculated as mg / (cm²). 2 •15h), to improve the alkali resistance stability R of optical glass OH (S) is divided into five levels, as shown in Table e.

[0125] Table e

[0126]

[0127] 13. Surface method wash resistance stability RP(S)

[0128] A 35mm × 35mm × 8mm sample, polished on all six sides, was immersed in Na₅P₃O₂ at a constant temperature of 50℃ ± 3℃ and a concentration of 0.01mol / L with thorough stirring. 10 In aqueous solution for 1 hour. Based on the average leaching mass per unit area, the unit is mg / (cm²). 2 The washability stability RP(S) of optical glass is divided into five levels, as shown in Table f.

[0129] Table f

[0130]

[0131] The refractive index nd, Abbe number υd, transition temperature Tg, and liquidus temperature L of the optical glasses prepared in Examples 1-24 and Comparative Examples 1-6 were compared. T When the external transmittance reaches 70%, the corresponding wavelength λ 70 When the external transmittance reaches 5%, the corresponding internal transmittance τ at wavelength λ5 and 460nm is... 10（460nm） Density ρ, Relative abrasive hardness (FA), Knoop hardness HK, Water resistance stability D W (Powder method), acid resistance stability D A (Powder method), stability against humid atmosphere R C (S) (Surface method), acid resistance stability R A (S)(Surface method), Alkali resistance stability R OH (S) (surface method), washability stability RP(S) (surface method), etc., are listed in Table 1-5.

[0132] Table 1: Examples 1 to 6

[0133]

[0134] Table 2: Examples 7 to 12

[0135]

[0136] Table 3: Examples 13-18

[0137]

[0138] Table 4: Examples 19-24

[0139]

[0140] Table 5: Comparative Examples 1-6

[0141]

[0142] As can be seen from Tables 1-4, the glass of embodiments (1-24) of the present invention has the required refractive index (n). d ) and Abbe number (υ d Its crystallization temperature is below 1160℃, and its transformation temperature T g With crystallization temperature (L) T The ratio of (T) g / L T The particle size distribution is not less than 0.6, enabling the formation of stable glass and allowing for mass production; the density is 4.98 g / cm³. 3The relative abrasive hardness (FA) is 100~150; the Knoop hardness (HK) is 600~750 GPa; it has high internal transmittance characteristics, and the internal transmittance τ of the 10mm thick optical glass at a wavelength of 460nm is... 10 (460nm) is 96%; in addition, the optical glass of the present invention also has excellent chemical stability.

[0143] The glasses of Comparative Examples (1-6) achieved the optical properties of refractive index (nd) and Abbe number (υd) required by the present invention. However, the crystallization temperature of the glasses of Comparative Examples 1-4 is higher than 1200°C, and Comparative Example 5 contains W, which is not conducive to improving the transmittance of the glass. The internal transmittance τ of the 10mm thick glass at a wavelength of 460nm is... 10 (460nm) below 92%; Comparative Example 6, although 10mm thick glass, has an internal transmittance τ at a wavelength of 460nm. 10 (460nm) reaches 96.1%, but contains expensive and heavy Gd element, resulting in high raw material costs, and the glass density is as high as 5.15g / cm³. 3 .

[0144] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0145] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An optical glass, characterized by, The optical glass comprises a glass matrix, which comprises the following components, based on the total mass of the glass matrix being 100%: B: 0.5% to 8.0%, preferably 1.0% to 7.0%; Si: 0.5% to 6%, preferably 1% to 6%; La: 30% to 55%, preferably 32% to 53%; Y: 0.5% to 12%, preferably 1.0% to 10%; Ti: 3.1% to 10.5%, preferably 4.2% to 9.9%; Nb: 0.9% to 9.5%, preferably 1.5% to 8.9%; Zn: 0% to 4.5%, preferably 0% to 3.0%; Zr: 0.9% to 8.4%, preferably 1.7% to 7.3%; O: 18.7% to 31.5%, preferably 19.9% to 30.8%; The optical glass has a refractive index of 2.00 to 2.03 and an Abbe number of 27 to 33.

2. The optical glass according to claim 1, characterized by The sum of the contents of La and Y elements, ∑(La+Y), is 32% to 65%, preferably 34% to 60%, based on the total mass of the glass matrix being 100%; The sum of the contents of Si and B elements, ∑(Si+B), is 4.8% to 10%, preferably 5.0% to 9%.

3. The optical glass according to claim 1, characterized by The ratio of the contents of Ti and Nb elements, Ti / Nb, is 0.5 to 3.5, preferably 1.0 to 3.0, based on the total mass of the glass matrix being 100%.

4. The optical glass according to claim 1, characterized by The ratio of the content of O element to the mass sum of Ti and Nb elements, O / (Ti+Nb), is 1 to 4, preferably 1.2 to 3, based on the total mass of the glass matrix being 100%.

5. Optical glass according to any one of claims 1 to 4, characterized in that The optical glass further comprises an additive component; preferably, the additive component comprises Li element and / or F element.

6. The optical glass according to claim 5, characterized by The content of the Li element is not more than 2000 ppm, preferably not more than 1500 ppm, and the content of the F element is not more than 1000 ppm, preferably not more than 900 ppm, based on the total mass of the glass matrix being 100%.

7. The optical glass according to any one of claims 1 to 6, characterized by, The optical glass does not contain one or more than two of Ba, Bi, Ge, Ta, Gd, Yb, W and Te.

8. The optical glass according to any one of claims 1 to 7, characterized by, The optical glass has one of the following characteristics: The optical glass has a density of 4.98 g / cm 3 The following: The optical glass has a crystallization temperature of 1160°C or lower; The wavelength λ at which the optical glass has an external transmittance of 70% 70 The wavelength λ5 at which the external transmittance is 5% is 370 nm or less at 410 nm or less. 10 mm thickness of the optical glass internal transmittance τ at 460 nm wavelength 10 96% or more; The optical glass has a relative grinding hardness FA of 100 to 150; The optical glass has a Knoop hardness HK of 600 GPa to 750 GPa.

9. A method of producing an optical glass according to any one of claims 1 to 8, characterized by, The method comprises weighing and uniformly mixing raw materials of the components of the optical glass according to the proportions, then melting, and then pouring or casting in a forming mold or directly pressing.

10. A light guide plate, characterized by, The optical glass according to any one of claims 1 to 9. The optical glass according to any one of claims 1 to 9.

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