CN111253063A

CN111253063A - Optical glass, optical preform, optical element and optical instrument

Info

Publication number: CN111253063A
Application number: CN201811472312.7A
Authority: CN
Inventors: 孙伟
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2018-12-03
Filing date: 2018-12-03
Publication date: 2020-06-09
Anticipated expiration: 2038-12-03
Also published as: CN111253063B

Abstract

The invention discloses an optical glass, wherein the component content of the optical glass is expressed by weight percentage, and the optical glass contains 15-35 wt.% of P₂O₅1-15 wt.% of Na₂O, 10-25 wt.% TiO₂38-52 wt.% of Nb₂O₅And 0-5 wt.% SiO₂And wherein TiO₂/Nb₂O₅The weight ratio is in the range of 0.22-0.6. The invention also discloses an optical prefabricated member made of the optical glass, an optical element made of the optical glass or the optical prefabricated member, and an optical instrument comprising the optical glass or the optical element. The optical glass of the present invention has a high refractive index, high dispersion and a low density.

Description

Optical glass, optical preform, optical element and optical instrument

Technical Field

The present invention relates to glass, and more particularly, to optical glass, and an optical preform, an optical element, and an optical instrument made of the optical glass.

Background

With the continuous fusion of optics and electronic information science and new material science, the application of optical glass as a photoelectron base material in the technical fields of light transmission, light storage, photoelectric display and the like is rapidly advanced. In recent years, optical elements and optical instruments have been rapidly developed in terms of digitization, integration, and high definition, and higher demands have been made on the performance of optical glasses used for optical elements of optical instruments and devices.

The high-refractive-index and high-dispersion optical glass has very important significance for simplifying an optical system and improving the imaging quality in the fields of optical design and optical communication. There is thus a continuing need for optical glasses for optical elements of optical instruments and devices having high refractive index and high dispersion.

In addition, the optical glass has optical constants such as high refractive index, high dispersion and the like, and simultaneously, the optical glass can realize the light weight of an optical system with lower density, and the finished product of the optical glass has better chemical stability so as to meet the application of the optical glass in the field of photoelectrons. There is still a need for optical glasses having improved above-mentioned properties.

Disclosure of Invention

To solve the problems in the related art, the present invention provides an optical glass having a high refractive index, high dispersion and low density. The inventors of the present invention have found that the above-mentioned technical problems can be solved and the objects of improved high refractive index, high dispersion and low density can be achieved by adjusting the weight percentages of the respective components constituting the optical glass and adjusting the ratios between the respective components.

In one aspect of the present invention, an optical glass is provided. The optical glass comprises 15 to 35 wt.% of P in percentage by weight₂O₅1-15 wt.% of Na₂O, 10-25 wt.% TiO₂38-52 wt.% of Nb₂O₅And 0-5 wt.% SiO₂And wherein TiO₂/Nb₂O₅The weight ratio is in the range of 0.22-0.6.

In one embodiment, P is contained in the optical glass in a weight percentage₂O₅20-30 wt.%, preferably 23-29 wt.%; na contained in the optical glass₂O is 2-10 wt.%, preferably 3-9.5 wt.%; TiO contained in the optical glass₂12-20 wt.%, preferably 13-19 wt.%; nb contained in the optical glass₂O₅40-50 wt.%, preferably 43-50 wt.%; SiO contained in the optical glass₂0-4 wt.%, preferably 0-2 wt.%; and wherein TiO₂/Nb₂O₅The weight ratio is in the range of 0.25 to 0.5, preferably 0.25 to 0.4.

In one embodiment, Nb₂O₅/(K₂O+Na₂O) is in the range of 2.0 to 10.0, preferably 4.0 to 9.0, more preferably 5.0 to 8.0.

In one embodiment, Na₂O/TiO₂The weight ratio is in the range of 0.2 to 1.2, preferably 0.3 to 1.0, more preferably 0.32 to 0.8.

In one embodiment, P₂O₅/(K₂O+Na₂O) in the range of 1.5 to 10.0, preferably 2.0 to 9.0, more preferably 3.2 to 6.75.

In one embodiment, P₂O₅/TiO₂The weight ratio is in the range of 0.9 to 3.0, preferably 1.0 to 2.5, more preferably 1.2 to 1.8.

In one embodiment, (P)₂O₅+SiO₂)/(TiO₂+Nb₂O₅) The weight ratio is in the range of 0.25 to 0.75, preferably 0.3 to 0.6, more preferably 0.37 to 0.55.

In one embodiment, the optical glass further comprises K as an optional component₂O、ZrO₂、ZnO、RO、Ln₂O₃、B₂O₃、Al₂O₃、WO₃、Li₂O and a clarifying agent, wherein, expressed in weight percent,

k contained therein₂O is 0-5 wt.%, preferably 0-3 wt.%, more preferably 0-2 wt.%;

ZrO contained therein₂0-5 wt.%, preferably 0-3 wt.%, more preferably 0-2 wt.%;

wherein the ZnO is contained in an amount of 0-8 wt.%, preferably 0-5 wt.%, more preferably 0-3 wt.%;

wherein RO is contained in the range of 0-10 wt.%, preferably 0-5 wt.%, more preferably 0-3 wt.%, wherein said RO is one or more of MgO, CaO, SrO and BaO;

ln contained therein₂O₃From 0 to 10 wt.%, preferably from 0 to 5 wt.%, more preferably from 0 to 3 wt.%, wherein Ln is present in the composition₂O₃Is La₂O₃、Gd₂O₃、Y₂O₃And Yb₂O₃One or more of;

b contained therein₂O₃0-5 wt.%, preferably 0-4 wt.%, more preferably 0-2 wt.%;

al contained therein₂O₃0-6 wt.%, preferably 0-4 wt.%, more preferably 0-3 wt.%;

WO contained therein₃0-8 wt.%, preferably 0-5 wt.%, more preferably 0-3 wt.%;

li contained therein₂O is 0-5 wt.%, preferably 0-3 wt.%, more preferably 0-1 wt.%;

wherein the clarifier is Sb and is 0-1%, preferably 0-0.5%₂O₃、SnO₂、SnO、CeO₂One or more of (a).

In one embodiment, Nb₂O₅/(B₂O₃+Na₂O) in the range of 2.5 to 15, preferably 3.5 to 10, more preferably 4.5 to 9.0.

In one embodiment, the optical glass has a refractive index (nd) of 1.92 to 1.98, preferably 1.93 to 1.98, more preferably 1.94 to 1.97; the Abbe number (vd) is 15 to 20, preferably 16 to 19.

In one embodiment, the optical glass has a glass transition temperature (T)_g) 700 ℃ or lower, preferably 690 ℃ or lower, more preferably 680 ℃ or lower; and/or a density (. rho.) of 3.7g/cm³Hereinafter, it is preferably 3.6g/cm³Hereinafter, more preferably 3.55g/cm³The following; and/or stability against water action (D)_W) Is 2 or more, preferably 1; and/or stability against acid action (D)_A) Is 2 or more, preferably 1, and/or a thermal expansion coefficient (α)_-30～70℃) Is 70X 10^-7Preferably 65X 10 or less,/K^-7A value of less than or equal to K, more preferably 60X 10^-7below/K; and/or the upper limit temperature of crystallization is 1200 ℃ or lower, preferably 1180 ℃ or lower, more preferably 1170 ℃ or lower; and/or a degree of bubbling of B class or more, preferably A class or more, more preferably A₀More than grade; and/or an elastic modulus (E) of 9000X 10⁷A value of 9500X 10 or more, preferably⁷A value of/Pa or more, more preferably 10000X 10⁷More than Pa.

In a second aspect of the present invention, there is provided an optical preform made of the optical glass of the present invention.

In a third aspect of the present invention, there is also provided an optical element made of the optical glass or optical preform of the present invention.

In a fourth aspect of the present invention, there is also provided an optical instrument comprising the above optical glass or optical element.

The invention can make the optical glass have low density on the premise of easily obtaining expected refractive index and dispersion by adjusting the weight percentage of each component forming the optical glass and the ratio of each component.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. In the present specification, the contents of the respective components (ingredients) are all expressed in terms of weight percentage with respect to the total amount of glass matter converted into the composition of oxides, if not specifically stated. Here, the "composition converted to oxides" means that when raw materials as the constituent components of the optical glass of the present invention are decomposed and converted to oxides when they are melted, the total amount of the oxides is 100%.

Unless otherwise indicated in a specific context, numerical ranges set forth herein include upper and lower values, and "above" and "below" include endpoints, all integers and fractions within the range, and are not limited to the specific values listed in the defined range. As used herein, "and/or" is inclusive, e.g., "A and/or B," and means A alone, B alone, or both A and B.

[ essential Components and optional Components ]

In the present invention, P₂O₅Is a skeleton component of a phosphate formula system, and mainly has the functions of reducing the melting temperature of glass and improving the thermal stability and light transmittance of the glass. When P is present₂O₅When the content is more than 35%, it is difficult to obtain high refractive index and high dispersion properties; when P is₂O₅When the content is less than 15%, the melting temperature of the optical glass is high and the transmittance of the glass is poor. Accordingly, in the optical glass of the present invention, P₂O₅The lower limit of the content range is 15%, preferably 20%, more preferably 23%; p₂O₅The upper limit of the content range is 35%, preferably 30%, more preferably 29%.

Nb₂O₅Is an essential component for imparting high-refractivity and high-dispersion properties to the optical glass of the present invention, while it is also capable of improving the chemical stability and devitrification resistance of the optical glass. When Nb₂O₅When the content of (b) is less than 38%, high refractive index and high dispersion properties cannot be obtained; when Nb is₂O₅When the content exceeds 52%, the devitrification resistance of the glass is lowered and the chemical stability is deteriorated. Therefore, in the optical glass of the present invention, Nb₂O₅The lower limit of the content range is 38%, preferably 40%, more preferably 43%, and the upper limit of the content range is 52%, preferably 50%.

Na₂O lowers the transition temperature of the glass and improves the melting property of the glass, and when the content thereof is less than 1%, the above effects are difficult to achieve, and when the content thereof is more than 15%, the refractive index of the glass decreases, and it is difficult to obtain the high refractive index required by the present invention. Thus Na in this application₂The O content is 1 to 15%, preferably 2 to 10%, more preferably 3 to 9.5%.

K₂O is an optional component for improving the stability and melting property of the glass, but when the content exceeds 5%, the devitrification resistance of the glass is lowered and the refractive index is lowered, so that K in the present application₂The O content is 0 to 5%, preferably 0 to 3%, more preferably 0 to 2%.

In some embodiments, when Nb₂O₅/(K₂O+Na₂O) value exceeding 10.0, the chemical stability of the glass is lowered, and Nb is added₂O₅/(K₂O+Na₂O) value less than 2.0, it is difficult for the glass to obtain high-refractivity and high-dispersion properties, so Nb in the present invention₂O₅/(K₂O+Na₂O) has a value of 2.0 to 10.0, and in some embodiments, it is preferred when Nb₂O₅/(K₂O+Na₂O) is 4.0 to 9.0Further, the glass bubble content can be increased, and Nb is more preferable₂O₅/(K₂O+Na₂O) is 5.0 to 8.0.

In some embodiments, when P₂O₅/(K₂O+Na₂O) of more than 10.0, the optical glass has poor melting property and a transition temperature (T)_g) High, when P is₂O₅/(K₂O+Na₂O) less than 1.5, the optical glass is liable to blister. Thus, P₂O₅/(K₂O+Na₂O) in the range of 1.5 to 10.0, preferably 2.0 to 9.0, more preferably 3.20 to 6.75, the optical glass has excellent bubble degree and a low transition temperature (T)_g)。

TiO₂The effect of (a) is to increase the chemical stability of the glass, while increasing the refractive index and dispersion value of the glass. When TiO is present₂When the content of (b) exceeds 25%, the devitrification resistance of the optical glass is lowered and the glass is colored, resulting in lowering of the transmittance of the glass in the visible light region; when TiO is in the glass₂When the content of (A) is less than 10%, the requirement of the optical glass in terms of chemical stability cannot be satisfied. Therefore, in the optical glass of the present invention, TiO₂The lower limit of the content range is 10%, preferably 12%, more preferably 13%, TiO₂The upper limit of the content range is 25%, preferably 20%, more preferably 19%.

In some embodiments, by controlling Na₂O/TiO₂In the range of 0.2 to 1.2, the glass can obtain a suitable high-temperature viscosity, is easy to process and produce, and reduces the thermal expansion coefficient and the transition temperature (T) of the optical glass_g). Preferably Na₂O/TiO₂In the range of 0.3 to 1.0, more preferably Na₂O/TiO₂In the range of 0.32-0.8. Na (Na)₂O/TiO₂Within the above range, has a low T_gThe optical glass has high refractive index and high dispersion, can be molded at a lower temperature when the glass is heated, and can reduce the degree of reaction with a mold when a precision glass mold is molded, thereby prolonging the service life of the mold.

In some embodiments, if P₂O₅/TiO₂If the glass content is more than 3.0, the optical glass has a low elastic modulus and a poor deformation resistance. If P is₂O₅/TiO₂When the thermal expansion coefficient is less than 0.9, the optical glass has a high thermal expansion coefficient and is easily deformed at high temperatures. By controlling P₂O₅/TiO₂The range of (B) is 0.9 to 3.0, and the elastic modulus of the optical glass can be increased and the thermal expansion coefficient of the glass can be decreased, and is preferably 1.0 to 5, more preferably 1.2 to 1.8.

In the present invention, by controlling TiO₂/Nb₂O₅In the range of 0.22 to 0.60, the optical glass can achieve a lower density while achieving high refractive index and high dispersion. Preferably TiO₂/Nb₂O₅Is in the range of 0.25 to 0.50, more preferably 0.25 to 0.40.

SiO₂Is a component for reducing glass coloration, improving the transmittance to short-wavelength visible light, promoting the formation of stable glass, and improving the devitrification resistance of glass in optical glass, but when SiO₂When the content of (B) exceeds 5%, the glass tends to be refractory. Therefore, in the optical glass of the present invention, SiO₂The upper limit of the content range is 5%, preferably 4%, more preferably 2%.

In some embodiments, when (P)₂O₅+SiO₂)/(TiO₂+Nb₂O₅) When it exceeds 0.75, the elastic modulus of the optical glass decreases, when (P)₂O₅+SiO₂)/(TiO₂+Nb₂O₅) When the amount is less than 0.25, the glass forming stability and chemical stability of the optical glass are lowered. Thus (P)₂O₅+SiO₂)/(TiO₂+Nb₂O₅) The range of (A) is 0.25 to 0.75, preferably 0.3 to 0.6, more preferably 0.37 to 0.55, and the optical glass has a high elastic modulus, and is excellent in glass forming stability and chemical stability.

In some embodiments, the optical glass of the present invention is prepared by SiO-containing the optical glass component₂/TiO₂In the range of more than 0 to 0.3, the optical glass may have a high elastic modulus and excellent devitrification resistance, preferably SiO₂/TiO₂Is 0.01 to 0.25, more preferably 0.01 to 0.1.

ZrO₂The component is an optional component in the optical glass of the present invention, and is a component for reducing coloring, improving transmittance to short-wavelength visible light, promoting formation of stable glass, and improving resistance to devitrification of glass. By making ZrO₂The content of the component (A) is 5% or less, and ZrO can be inhibited₂The refractive index decreases due to the component, and a desired high refractive index is easily obtained. Thus, in the optical glass of the present invention, ZrO₂The upper limit of the content range is 5%, preferably 3%, more preferably 2%.

ZnO, which improves the refractive index of the glass, improves the glass stability, meltability, press-formability and lowers the glass transition temperature, is an optional component in the optical glass of the present invention. By setting the content of the ZnO component to 8% or less, a desired high refractive index and a desired high dispersion value can be easily obtained. Therefore, in the optical glass of the present invention, the upper limit of the ZnO content range is 8%, preferably 5%, and more preferably 3%.

B₂O₃Is a component which forms a glass network and improves the resistance of the glass to devitrification, and is an optional component in the present invention, but when the content exceeds 5%, the refractive index and dispersion value of the glass are lowered. Thus, in the optical glass of the present invention, B₂O₃The upper limit of the content range is 5%, preferably 4%, more preferably 2%.

In some embodiments, if Nb₂O₅/(B₂O₃+Na₂O) of more than 15.0, the optical glass has poor melting property and a transition temperature (T)_g) Is higher. If Nb₂O₅/(B₂O₃+Na₂O) is less than 2.5, the optical glass is easy to crystallize, and the finished glass has more bubbles. Let Nb₂O₅/(B₂O₃+Na₂O) is in the range of 2.5 to 15.0, preferably 3.5 to 10.0, more preferably 4.5 to 9.0, and the optical glass has good meltability, excellent devitrification resistance and a blister degree.

Al₂O₃Is a component for improving the chemical stability of glass and increasing the viscosity of glass during melting,is an optional component in the optical glass of the present invention. By making Al₂O₃The content of the component (A) is 6% or less, and the meltability of the glass can be improved and the devitrification tendency of the glass can be reduced. Therefore, in the optical glass of the present invention, Al₂O₃The upper limit of the content range is 6%, preferably 4%, more preferably 3%.

WO₃Is a component for increasing the refractive index of the glass and increasing the dispersion value of the glass, and is an optional component in the optical glass of the present invention. By reacting WO₃The content of the component (A) is 8% or less, and the transmittance of the glass to short-wavelength visible light can be suppressed, and a desired high refractive index and a desired high dispersion value can be easily obtained. Therefore, in the optical glass of the present invention, WO₃The upper limit of the content range is 8%, preferably 5%, more preferably 3%. WO₃The lower limit of the content range may be zero.

Li₂O is a component for increasing the melting property of the glass and lowering the glass transition temperature, and is an optional component in the optical glass of the present invention. By reacting Li₂The content of the O component is 5% or less, and the desired high refractive index can be easily obtained, and the crystallization upper limit temperature of the glass can be lowered to improve the stability of the glass. Therefore, in the optical glass of the present invention, Li₂The upper limit of the O content range is 5%, preferably 3%, more preferably 1%. Li₂The lower limit of the O content range may be zero.

RO (i.e., one or more of MgO, CaO, SrO, and BaO) is a component that lowers the devitrification temperature of the glass and improves the resistance of the glass to devitrification, and is an optional component in the optical glass of the present invention. By controlling the RO content to 10% or less, the glass can be inhibited from suffering devitrification resistance and chemical stability. Therefore, in the optical glass of the present invention, the upper limit of the range of RO content is 10%, preferably 5%, more preferably 3%.

Ln₂O₃Is a component for increasing the refractive index of the glass and improving the chemical stability of the glass, is an optional component in the optical glass of the present invention, wherein Ln₂O₃Is La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃One or more of (a). By mixing Ln₂O₃The content of (2) is controlled to 10% or less, and the devitrification resistance of the glass can be improved. Thus, in the optical glass of the present invention, Ln₂O₃The upper limit of the content range is 10%, preferably 5%, more preferably 3%.

By adding 0-1% of Sb₂O₃、SnO₂SnO and CeO₂One or more components of the glass refining agent can be used as a refining agent to improve the refining effect of the glass. But when Sb is₂O₃When the content exceeds 1%, the glass tends to have a reduced fining property and the deterioration of the forming mold is promoted by the strong oxidation thereof, so that Sb in the present invention is₂O₃The amount of (B) is 1% or less, preferably 0.5% or less. SnO₂SnO may be added as a fining agent, but when the content exceeds 1%, the glass is colored, or when the glass is heated, softened and press-molded again, Sn tends to become a starting point of nucleation and devitrification occurs, so that the SnO of the present invention₂And SnO are contained in an amount of 1% or less, preferably 0.5% or less, and more preferably not added. CeO (CeO)₂Action and addition amount ratio of (B) and SnO₂The content is 1% or less, preferably 0.5% or less, and more preferably no addition.

[ regarding components that should not be contained ]

If necessary, other components not mentioned above can be added within a range not impairing the characteristics of the glass of the present invention. However, since the glass is colored and absorbs at a specific wavelength in the visible light region even when a small amount of a transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo is contained alone or in combination, thereby reducing the property of the present invention to improve the effect of the visible light transmittance, it is preferable that the optical glass, which requires transmittance at a wavelength in the visible light region, is not substantially contained.

Cations of Th, Cd, T1, Os, Be, and Se tend to Be used as harmful chemical substances in recent years, and measures for protecting the environment are required not only in the glass production process but also in the processing process and disposal after commercialization. Therefore, when importance is attached to the influence on the environment, it is preferable that these components are not substantially contained except for inevitable mixing. Thereby, the optical glass becomes practically free from substances contaminating the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and discarded without taking special measures for environmental countermeasures.

In order to achieve environmental friendliness, the optical glass of the present invention does not contain As₂O₃And PbO. Although As₂O₃Has the effects of eliminating bubbles and better preventing the glass from coloring, but As₂O₃The addition of (b) increases the platinum attack of the glass on the furnace, particularly on the platinum furnace, resulting in more platinum ions entering the glass, which adversely affects the service life of the platinum furnace. PbO can significantly improve the high-refractivity and high-dispersion properties of the glass, but PbO and As₂O₃All cause environmental pollution.

The glass of the invention is produced by adopting conventional raw materials and conventional processes, and phosphoric acid, metaphosphate, pyrophosphate or phosphorus pentoxide is used as P₂O₅The raw materials are carbonate, nitrate, sulfate, oxide and the like as other component raw materials. After the materials are mixed according to a conventional method, the mixed furnace materials are put into a smelting furnace with the temperature of 1200-1280 ℃ for smelting, and after clarification and full homogenization, the optical glass can be obtained by casting or slip casting at the temperature of 1150-1200 ℃. Those skilled in the art can appropriately select the raw materials, the process method and the process parameters according to the actual needs.

The performance parameters of the optical glass of the present invention were measured in the following manner.

[ refractive index and Abbe number ]

The refractive index (nd) and Abbe number (vd) were measured according to GB/T7962.1-2010.

The optical glass of the present invention has a refractive index (nd) of 1.92 to 1.98, preferably 1.93 to 1.98, more preferably 1.94 to 1.97; the Abbe number (vd) of the optical glass of the present invention is 15 to 20, preferably 16 to 19.

[ transition temperature ]

Transition temperature (T)_g) Testing according to GB/T7962.16-2010.

Glass transition temperature (T) of the optical glass of the present invention_g) Is 700 ℃ or lower, preferably 690 ℃ or lower, and more preferably 680 ℃ or lower.

[ Density ]

The density (. rho.) was tested in accordance with GB/T7962.20-2010.

The optical glass of the present invention has a density (. rho.) of 3.7g/cm³Hereinafter, it is preferably 3.6g/cm³Hereinafter, more preferably 3.55g/cm³The following.

[ chemical stability ]

Chemical stability in the present invention includes water-resistant stability (D)_W) And stability against acid action (D)_A) It was tested according to GB/T17129.

Stability to Water of the optical glass of the present invention (D)_W) Is 2 or more, preferably 1; stability against acid action of the optical glass of the present invention (D)_A) Is 2 or more, preferably 1.

[ coefficient of thermal expansion ]

Coefficient of thermal expansion (α)_-30～70℃) Testing according to GB/T7962.16-2010.

The thermal expansion coefficient (α) of the optical glass of the present invention_-30～70℃) Is 70X 10^-7Preferably 65X 10 or less,/K^-7A value of less than or equal to K, more preferably 60X 10^-7and/K is less than or equal to.

[ degree of bubbling ]

The bubble degree was tested according to GB/T7962.8-2010.

The optical glass of the present invention has a bubble degree of B class or more, preferably A class or more, more preferably A class₀More than grade.

[ upper limit temperature of crystallization ]

Measuring the crystallization performance of the glass by adopting a gradient temperature furnace method, manufacturing the glass into a sample of 180 x 10mm, polishing the side surface, putting the sample into a furnace with a temperature gradient (5 ℃/cm), heating to 1400 ℃, keeping the temperature for 4 hours, taking out the sample, naturally cooling to room temperature, observing the crystallization condition of the glass under a microscope, wherein the highest temperature corresponding to the occurrence of crystals of the glass is the crystallization upper limit temperature of the glass.

The upper limit temperature of crystallization of the optical glass of the present invention is 1200 ℃ or lower, preferably 1180 ℃ or lower, and more preferably 1170 ℃ or lower.

[ modulus of elasticity ]

The elastic modulus is expressed as Young's modulus and is measured as follows: the Young's modulus (E) of the glass is obtained by measuring the longitudinal wave velocity and the transverse wave velocity of the glass by ultrasonic waves and calculating according to the following formula.

Wherein the content of the first and second substances,

in the formula:

e is Young's modulus, Pa;

g is shear modulus, Pa;

V_Tis the transverse wave velocity, m/s;

V_sis the longitudinal wave velocity, m/s;

rho is the density of the glass, g/cm³。

The elastic modulus (E) of the optical glass of the present invention is 9000X 10⁷A value of 9500X 10 or more, preferably⁷A value of/Pa or more, more preferably 10000X 10⁷More than Pa.

The present invention also provides an optical preform made of the optical glass of the present invention, an optical element made of the optical glass or the optical preform of the present invention, and an optical instrument comprising the above optical glass or the optical element.

The present invention can easily obtain a desired high refractive index, high dispersion and low density by adjusting the weight percentages of the components constituting the optical glass and adjusting the ratios between the components. Meanwhile, the optical glass also has excellent glass forming stability, excellent chemical stability and bubble degree and low T_gSo that the optical glass can be processed and molded at lower temperature, and the finished optical glass has the characteristics of better chemical stability, low expansion rate, high elastic modulus and the like so as to meet the application of the optical glass in the field of photoelectrons.

The optical preform and the optical element of the present invention are each formed of the above-described optical glass of the present invention. The optical preform of the present invention has excellent characteristics possessed by optical glass; the optical element of the present invention has excellent characteristics of optical glass, and can provide optical elements such as various lenses and prisms having high optical values.

Examples of the lens include various lenses such as a concave meniscus lens, a convex meniscus lens, a double convex lens, a double concave lens, a plano-convex lens, and a plano-concave lens, each of which has a spherical or aspherical lens surface.

Further, since the prism has a relatively high refractive index, by combining the prism with an imaging optical system and bending the optical path to direct the prism in a desired direction, a compact and wide-angle optical system can be realized.

The optical element formed by the optical glass can be used for manufacturing optical instruments such as photographic equipment, camera equipment, display equipment, monitoring equipment and the like.

The present invention is described in detail below with reference to various embodiments.

In the following examples and comparative examples, optical glasses were prepared as follows:

weighing raw materials corresponding to the optical glass components in proportion, fully mixing, adding into a platinum crucible, melting, clarifying, homogenizing and cooling at 1280 ℃ of 1200-; pouring the molten glass into the preheated metal mold at the temperature of 1150-1200 ℃; the molten glass and the metal mold are placed in an annealing furnace together, and the optical glass is obtained after slow cooling annealing. The various performance parameters of the optical glass were measured according to the measurement methods described hereinbefore.

The compositions of the optical glasses of examples 1 to 40 and comparative examples 1 to 6 are shown in tables 1 and 2 below, respectively; the corresponding properties of the optical glasses of examples 1 to 40 and comparative examples 1 to 6 are shown in tables 3 and 4, respectively.

Table 4: optical glass Properties of comparative examples 1 to 6

As can be seen from the above tables 1 and 3, when the weight percentages of the components and the ratios between the components in the optical glass are within the ranges of the present invention, an optical glass having a desired high refractive index, high dispersion, low density can be obtained. Meanwhile, the optical glass is remarkably improved in the aspects of optical performance, processability, glass forming stability, chemical stability, low density, deformation resistance, crystallization resistance, low bubble degree and the like.

When the weight percentage of each component in the optical glass and the ratio of each component are in the range, the optical glass can be processed and molded at low density and lower temperature while having optical constants such as refractive index, Abbe number and the like, and the finished optical glass has the characteristics of good chemical stability, low expansion rate and the like so as to meet the application of the optical glass in the field of photoelectrons.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. Optical glass, characterized in that its composition, expressed in weight percentage, comprises 15-35 wt.% of P₂O₅1-15 wt.% of Na₂O, 10-25 wt.% TiO₂38-52 wt.% of Nb₂O₅And 0-5 wt.% SiO₂And wherein TiO₂/Nb₂O₅The weight ratio is in the range of 0.22-0.6.

2. Optical glass according to claim 1, characterised in that its composition, expressed in weight percentage, comprises P₂O₅20-30 wt.%, preferably 23-29 wt.%; na contained in the optical glass₂O is 2-10 wt.%, preferably 3-9.5 wt.%; TiO contained in the optical glass₂12-20 wt.%, preferably 13-19 wt.%; nb contained in the optical glass₂O₅40-50 wt.%, preferably 43-50 wt.%; SiO contained in the optical glass₂0-4 wt.%, preferably 0-2 wt.%; and wherein TiO₂/Nb₂O₅The weight ratio is in the range of 0.25 to 0.5, preferably 0.25 to 0.4.

3. Optical glass according to any of claims 1 or 2, characterised in that Nb₂O₅/(K₂O+Na₂O) is in the range of 2.0 to 10.0, preferably 4.0 to 9.0, more preferably 5.0 to 8.0.

4. An optical glass according to any of claims 1 or 2, characterised in that Na₂O/TiO₂The weight ratio is in the range of 0.2 to 1.2, preferably 0.3 to 1.0, more preferably 0.32 to 0.8.

5. The optical glass according to any of claims 1 or 2, wherein P is₂O₅/(K₂O+Na₂O) weight ratioIn the range of 1.5 to 10.0, preferably 2.0 to 9.0, more preferably 3.2 to 6.75.

6. The optical glass according to any of claims 1 or 2, wherein P is₂O₅/TiO₂The weight ratio is in the range of 0.9 to 3.0, preferably 1.0 to 2.5, more preferably 1.2 to 1.8.

7. The optical glass according to any of claims 1 or 2, wherein (P)₂O₅+SiO₂)/(TiO₂+Nb₂O₅) The weight ratio is in the range of 0.25 to 0.75, preferably 0.3 to 0.6, more preferably 0.37 to 0.55.

8. The optical glass according to any of claims 1 or 2, wherein the optical glass further comprises K as an optional component₂O、ZrO₂、ZnO、RO、Ln₂O₃、B₂O₃、Al₂O₃、WO₃、Li₂O and a clarifying agent, wherein, expressed in weight percent,

k contained in the optical glass₂O is 0-5 wt.%, preferably 0-3 wt.%, more preferably 0-2 wt.%;

ZrO contained in the optical glass₂0-5 wt.%, preferably 0-3 wt.%, more preferably 0-2 wt.%;

the ZnO is contained in the optical glass in an amount of 0 to 8 wt.%, preferably 0 to 5 wt.%, more preferably 0 to 3 wt.%;

RO is contained in the optical glass in an amount of 0 to 10 wt.%, preferably 0 to 5 wt.%, more preferably 0 to 3 wt.%, wherein the RO is one or more of MgO, CaO, SrO and BaO;

ln contained in the optical glass₂O₃From 0 to 10 wt.%, preferably from 0 to 5 wt.%, more preferably from 0 to 3 wt.%, wherein Ln is present in the composition₂O₃Is La₂O₃、Gd₂O₃、Y₂O₃And Yb₂O₃One or more of;

b contained in the optical glass₂O₃0-5 wt.%, preferably 0-4 wt.%, more preferably 0-2 wt.%;

al contained in the optical glass₂O₃0-6 wt.%, preferably 0-4 wt.%, more preferably 0-3 wt.%;

WO contained in the optical glass₃0-8 wt.%, preferably 0-5 wt.%, more preferably 0-3 wt.%;

li contained in the optical glass₂O is 0-5 wt.%, preferably 0-3 wt.%, more preferably 0-1 wt.%

The optical glass comprises 0 to 1 percent of clarifying agent, preferably 0 to 0.5 percent of clarifying agent, wherein the clarifying agent is Sb₂O₃、SnO₂、SnO、CeO₂One or more of (a).

9. The optical glass of claim 8, wherein Nb₂O₅/(B₂O₃+Na₂O) in the range of 2.5 to 15, preferably 3.5 to 10, more preferably 4.5 to 9.0.

10. The optical glass according to any of claims 1 to 9, wherein the refractive index (nd) of the optical glass is from 1.92 to 1.98, preferably from 1.93 to 1.98, more preferably from 1.94 to 1.97; the Abbe number (vd) is 15 to 20, preferably 16 to 19.

11. The optical glass according to any of claims 1 to 9, wherein the glass transition temperature (T) of the optical glass_g) 700 ℃ or lower, preferably 690 ℃ or lower, more preferably 680 ℃ or lower; and/or a density (. rho.) of 3.7g/cm³Hereinafter, it is preferably 3.6g/cm³Hereinafter, more preferably 3.55g/cm³The following; and/or stability against water action (D)_W) Is 2 or more, preferably 1; and/or stability against acid action (D)_A) Is 2 or more, preferably 1, and/or a thermal expansion coefficient (α)_-30～70℃) Is 70×10^-7Preferably 65X 10 or less,/K^-7A value of less than or equal to K, more preferably 60X 10^-7below/K; and/or the upper limit temperature of crystallization is 1200 ℃ or lower, preferably 1180 ℃ or lower, more preferably 1170 ℃ or lower; and/or a degree of bubbling of B class or more, preferably A class or more, more preferably A₀More than grade; and/or an elastic modulus (E) of 9000X 10⁷A value of 9500X 10 or more, preferably⁷A value of/Pa or more, more preferably 10000X 10⁷More than Pa.

12. An optical preform, characterized in that it is made of an optical glass according to any one of claims 1 to 11.

13. Optical element, characterized in that it is made of an optical glass according to any of claims 1 to 11 or an optical preform according to claim 12.

14. An optical device comprising the optical glass according to any one of claims 1 to 11 or comprising the optical element according to claim 13.