CN110937801A

CN110937801A - Optical glass, glass preform, optical element and optical instrument

Info

Publication number: CN110937801A
Application number: CN201911310582.2A
Authority: CN
Inventors: 蔡冬雪
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2019-12-18
Filing date: 2019-12-18
Publication date: 2020-03-31
Anticipated expiration: 2039-12-18
Also published as: CN114685041B; CN110937801B; CN114685041A

Abstract

The invention provides optical glass, which comprises the following components in percentage by weight: p₂O₅：4～30％；BaO：0～20％；Nb₂O₅：10～45％；Li₂O+K₂O+Na₂O: 0 to 35 percent; wherein BaO/Nb₂O₅0 to 0.5. Through reasonable component design, the optical glass has a lower temperature coefficient of refractive index while having an expected refractive index and Abbe number, and brings greater freedom for correcting temperature drift of a fixed-focus lens; the optical lens has excellent chemical stability and anti-crystallization capability, the transmittance can not be obviously reduced after long-term use, and the optical lens is very suitable for being used in a vehicle-mounted lens, and is particularly suitable for being applied to imaging applications which need to bear severe working environments, such as sand wind, mud, rapid temperature change and the like.

Description

Optical glass, glass preform, optical element and optical instrument

Technical Field

The invention relates to optical glass, in particular to optical glass with a refractive index of 1.73-1.81 and an Abbe number of 20-30.

Background

In the prior art, glass with a refractive index of 1.73-1.81 and an Abbe number of 20-30 belongs to high-refractive-index high-dispersion optical glass, and is widely applied to various lens designs. In recent years, vehicle-mounted lens devices have been developed vigorously, and the quality of the vehicle-mounted lens device is related to safety compared with general photography, so the design of the vehicle-mounted lens device emphasizes the reliability of the device, and particularly, the device is exposed outside a vehicle body and needs to bear severe working environments, such as a reversing camera, a front-view camera, a rearview mirror auxiliary camera and the like.

The principle of designing a vehicle-mounted lens meeting the severe working environment is that the structure is as simple as possible, and the more complex the structure is, the worse the reliability is. Therefore, in order to meet the design requirement of long service life (more than ten years) of the vehicle-mounted lens suitable for severe working environment, the optical design generally adopts the design of a fixed-focus lens, the number of lenses of the fixed-focus lens is less than that of zoom lenses, and meanwhile, a zooming driving structure is not arranged, so that the reliability is greatly improved compared with that of the zoom lenses.

Although the prime lens has excellent reliability, the prime weakness of the prime lens is that it is very difficult to correct the temperature drift of the lens when the prime lens is applied to a vehicle. The temperature drift of the lens means that when the temperature changes dramatically, for example, day and night temperature difference in desert area reaches 60 ℃, under the scene of very large temperature difference such as automobile driving from tropical zone to cold zone, the focal length of the lens changes, thereby causing imaging blur. For automobiles, safety is the first place, and therefore, a vehicle-mounted camera needs to keep clear imaging under the condition of rapid temperature change.

For optical designs, more different types of lens combinations and zoom systems can be used to address the temperature drift problem. However, due to the reliability requirement of the vehicle-mounted system, the temperature drift problem needs to be solved on the fixed-focus imaging system with few lenses (even 3 lenses), so that the development of the optical glass with the specific temperature coefficient of refractive index is required, and the development of the times puts forward a new subject for optical design and optical material research.

The prior art optical glass with a refractive index of 1.73-1.81 and an Abbe number of 20-30 has a refractive index temperature coefficient value, namely d-line dn/dt relative (10), in the range of 40-60 DEG C^-6/deg.C) is substantially 1.0 to 2.1(10 ℃)^-6/° c), see table 1 below. If glasses with temperature coefficients of refractive index below-2.0, even below-3.0, and at higher gloss levels could be developed, the above temperature drift problem could be effectively addressed in the design.

Table 1: temperature coefficient of refractive index of 20-30 flint glass with partial refractive index of 1.73-1.81 and Abbe number

Serial number	n_d	ν_d	D-line dn/dtrelative (10) at 40-60 deg.C^-6/℃)
				Example 1	1.7373	29.50	1.0
Example 2	1.7400	28.30	2.1
				Example 3	1.7847	25.72	1.4

However, if the above-mentioned optical glass having refractive index and Abbe number is required to have a temperature coefficient of refractive index lower than-2.0, the composition design is different from the conventional one, and problems such as poor devitrification resistance of the glass and difficulty in eliminating striae and blisters are generally caused. If the anti-crystallization capacity of the glass is poor, the production difficulty of the glass blank is increased, so that the yield is reduced, and even normal production cannot be realized in severe cases; secondly, crystal precipitation is easy to generate in the secondary compression process, so that the yield is reduced, and even secondary compression can not be carried out. For the glass material applied in the vehicle-mounted field, if the production yield of the glass is low and the glass cannot be manufactured by adopting a secondary pressing method but a cold working method, the cost is greatly increased.

Disclosure of Invention

The invention aims to provide optical glass with a low temperature coefficient of refractive index and excellent anti-devitrification performance.

The technical scheme adopted by the invention for solving the technical problem is as follows:

(1) the optical glass comprises the following components in percentage by weight: p₂O₅：4～30％；BaO：0～20％；Nb₂O₅：10～45％；Li₂O+K₂O+Na₂O: 0 to 35 percent; wherein BaO/Nb₂O₅0 to 0.5.

(2) The optical glass according to (1), which comprises the following components in percentage by weight: SiO 2₂：0～10％；B₂O₃：0～10％；Gd₂O₃：0～8％；Y₂O₃：0～5％；Al₂O₃：0～3％；TiO₂: 0 to 15 percent; MgO: 0 to 5 percent; CaO: 0 to 25 percent; SrO: 0 to 10 percent; a clarifying agent: 0 to 1 percent.

(3) Optical glass having a composition expressed in weight percent by P₂O₅：4～30％；Nb₂O₅：10～45％；Li₂O+K₂O+Na₂O：0～35％；SiO₂：0～10％；B₂O₃：0～10％；Gd₂O₃：0～8％；Y₂O₃：0～5％；Al₂O₃：0～3％；TiO₂: 0 to 15 percent; MgO: 0 to 5 percent; CaO: 0 to 25 percent; SrO: 0 to 10 percent; BaO: 0 to 20 percent; a clarifying agent: 0 to 1% of a composition of BaO/Nb₂O₅0 to 0.5.

(4) Optical glass containing P₂O₅、Nb₂O₅Alkaline earth metal oxides and alkali metal oxides, the components of which are expressed in weight percent, wherein BaO/Nb₂O₅0 to 0.5, Li₂O/(K₂O+Na₂O) is 0.5 or less, and the refractive index n of the optical glass_d1.73 to 1.81, Abbe number v_dIs 20 to 30 percent of the total weight of the composition,temperature coefficient of refractive index dn/dt of-2X 10^-6Below/° c.

(5) The optical glass according to (4), which comprises the following components in percentage by weight: p₂O₅: 4-30%; and/or Nb₂O₅: 10-45%; and/or Li₂O+K₂O+Na₂O: 0 to 35 percent; and/or SiO₂: 0 to 10 percent; and/or B₂O₃: 0 to 10 percent; and/or Gd₂O₃: 0-8%; and/or Y₂O₃: 0 to 5 percent; and/or Al₂O₃: 0 to 3 percent; and/or TiO₂: 0 to 15 percent; and/or MgO: 0 to 5 percent; and/or CaO: 0 to 25 percent; and/or SrO: 0 to 10 percent; and/or BaO: 0 to 20 percent; and/or a clarifying agent: 0 to 1 percent.

(6) The optical glass according to any one of (1) to (5), which comprises the following components in percentage by weight: p₂O₅: 10-30%; and/or Nb₂O₅: 15-45%; and/or Li₂O+K₂O+Na₂O: 5-30%; and/or SiO₂: 0-8%; and/or B₂O₃: 1-9%; and/or Gd₂O₃: 0-6%; and/or Y₂O₃: 0 to 4 percent; and/or Al₂O₃: 0-2%; and/or TiO₂: 0 to 12 percent; and/or MgO: 0 to 3 percent; and/or CaO: 0 to 20 percent; and/or SrO: 0-8%; and/or BaO: 0 to 16 percent; and/or a clarifying agent: 0 to 0.5 percent.

(7) The optical glass according to any one of (1) to (5), which comprises the following components in percentage by weight: p₂O₅: 15-25%; and/or Nb₂O₅: 20-43%; and/or Li₂O+K₂O+Na₂O: 5-25%; and/or SiO₂: 0 to 5 percent; and/or B₂O₃: 2-8%; and/or Gd₂O₃: 0 to 4 percent; and/or Y₂O₃: 0 to 3 percent; and/or Al₂O₃: 0 to 1 percent; and/or TiO₂: 0 to 10 percent; and/or CaO: 0 to 15 percent; and/or SrO: 0-6%; and/or BaO: 0 to 13 percent; and/or clarificationCleaning agent: 0 to 0.1%.

(8) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein BaO/Nb₂O₅0 to 0.4, preferably BaO/Nb₂O₅0 to 0.3.

(9) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein (SiO)₂+B₂O₃)/P₂O₅0.1 to 0.5, preferably (SiO)₂+B₂O₃)/P₂O₅0.15 to 0.45, more preferably (SiO)₂+B₂O₃)/P₂O₅0.2 to 0.4.

(10) The optical glass according to any one of (1) to (5), wherein the component is represented by weight percentage, wherein TiO₂/Nb₂O₅Has a value of 1 or less, preferably TiO₂/Nb₂O₅A value of (2) is 0.8 or less, and TiO is more preferable₂/Nb₂O₅The value of (A) is 0.5 or less.

(11) The optical glass according to any one of (1) to (5), wherein CaO/(BaO + SrO) is 0 to 0.5, preferably CaO/(BaO + SrO) is 0 to 0.4, and more preferably CaO/(BaO + SrO) is 0 to 0.3, in terms of weight percentage.

(12) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein Li₂O/(K₂O+Na₂O) is 0.5 or less, preferably Li₂O/(K₂O+Na₂O) is 0.4 or less, more preferably Li₂O/(K₂O+Na₂O) is 0.3 or less.

(13) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein Na₂O/K₂O is 0.1 to 1.5, preferably Na₂O/K₂O is 0.2 to 1.2, more preferably Na₂O/K₂O is 0.3 to 1.0.

(14) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.5, preferably (C)BaO+SrO+CaO)/(Nb₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.4, more preferably (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.3.

(15) The optical glass according to any one of (1) to (5), wherein the composition is represented by weight percentage, wherein (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 1.0, preferably (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 0.8, more preferably (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 0.6.

(16) The optical glass according to any one of (1) to (5), wherein the component(s) is (are) Na in percentage by weight₂O: 0 to 15%, preferably Na₂O: 2 to 12%, more preferably Na₂O: 4-10%; and/or K₂O: 0 to 25%, preferably K₂O: 3 to 20%, more preferably K₂O: 5-15%; and/or Li₂O: 0 to 5%, preferably Li₂O: 0 to 3%, more preferably no Li is added₂O。

(17) The optical glass according to any one of (1) to (5), wherein the content of BaO is not less than the content of CaO, preferably the content of SrO is not less than the content of CaO, and more preferably the content of BaO is not less than the content of SrO is not less than the content of CaO.

(18) The optical glass according to any one of (1) to (5), wherein the refractive index n of the optical glass_d1.73 to 1.81, preferably 1.74 to 1.80, more preferably 1.75 to 1.79; abbe number v_d20 to 30, preferably 21 to 28, and more preferably 22 to 26.

(19) The optical glass according to any one of (1) to (5), wherein the temperature coefficient of refractive index dn/dt at 40 to 60 ℃ of the optical glass is-2X 10^-6Lower than/° C, preferably-2.5X 10^-6Less than or equal to/° C, more preferably-3.0X 10^-6Not more than 4.0X 10 ℃ C, preferably not more than^-6Below/° c.

(20) The optical glass according to any one of (1) to (5), which has a water-resistant stability D_WIs 3 or more, preferably 2 or more, more preferablySelecting as class 1; and/or the degree of streaking is at least level C, preferably at least level B, more preferably at level A.

(21) A glass preform made of the optical glass according to any one of (1) to (20).

(22) An optical element produced from the optical glass according to any one of (1) to (20), or the glass preform according to (21).

(23) An optical device comprising the optical glass according to any one of (1) to (20) or the optical element according to (22).

The invention has the beneficial effects that: through reasonable component design, the optical glass has a lower temperature coefficient of refractive index while having an expected refractive index and Abbe number, and brings greater freedom for correcting temperature drift of a fixed-focus lens; the optical lens has excellent chemical stability and anti-crystallization capability, the transmittance can not be obviously reduced after long-term use, and the optical lens is very suitable for being used in a vehicle-mounted lens, and is particularly suitable for being applied to imaging applications which need to bear severe working environments, such as sand wind, mud, rapid temperature change and the like.

Detailed Description

The optical glass of the present invention is obtained by the following steps, which are not limited to the above-described embodiments, and can be appropriately modified within the scope of the object of the present invention. Note that, although the description of the duplicate description may be appropriately omitted, the gist of the invention is not limited to this. The optical glass of the present invention may be simply referred to as glass in the following.

[ optical glass ]

The ranges of the respective components of the optical glass of the present invention are explained below. In the present specification, the contents of the respective components 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 oxides, complex salts, hydroxides, and the like used as raw materials of the optical glass composition component (component) of the present invention are decomposed in the melt and converted to oxides, the total amount of the oxides is 100%.

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

< essential Components and optional Components >

The glass of the invention mainly contains P₂O₅、Nb₂O₅RO (RO is more than one of MgO, CaO, SrO and BaO), R₂O(R₂0 is Li₂O、K₂O、Na₂More than one of O), the desired refractive index and Abbe number are obtained through reasonable component distribution ratio, the temperature coefficient of the refractive index is low, the chemical stability is excellent, the anti-crystallization capability is strong, the transmittance is not obviously reduced after long-term use, and the optical lens is very suitable for being used in vehicle-mounted lenses.

P₂O₅The glass is a network former which forms the glass of the invention, is the basis for forming the glass, and the content of the glass is closely related to key indexes such as chemical stability, refractive index, Abbe number and the like of the glass. Due to tetrahedron [ PO ]₄]One double bond in the four bonds can break and deform a vertex angle of the tetrahedron, so that the glass can obtain a loose network structure and has a larger thermal expansion coefficient, and a desired negative refractive index temperature coefficient is obtained. Wherein, if P₂O₅The content of the P-containing compound is more than 30 percent, the network structure of the glass is excessively loose, so that the chemical stability, particularly the stability of water resistance is reduced, the glass can be deliquesced when the chemical stability, particularly the stability of water resistance, is more serious, and the refractive index and the Abbe number of the glass can not meet the design requirements, therefore, the P-containing compound in the invention₂O₅The upper limit of the content of (b) is 30%, preferably 25%; if P₂O₅Is less than 4%, the temperature coefficient of refractive index of the glass does not meet the design requirements, therefore, P₂O₅The lower limit of (B) is 4%, the lower limit is preferably 10%, and the lower limit is more preferably 15%.

To be atP₂O₅The glass maintains good chemical stability under the condition of higher content, and the inventor finds that the proper amount of SiO is added₂、B₂O₃The components can improve the chemical stability and the anti-devitrification performance of the glass.

Specifically, B₂O₃As network formers, their action with P₂O₅Similarly. In a glassy state P₂O₅Adding B₂O₃The layered or interwoven chain structure can be made to approach the skeleton structure, and the chemical stability of the glass is improved. But B₂O₃If the content is more than 10%, the structure of the glass is more compact, so that the thermal expansion coefficient of the glass is reduced, and the temperature coefficient of the refractive index is increased. Thus, B₂O₃The content of (b) is limited to 0 to 10%, preferably 1 to 9%, more preferably 2 to 8%.

SiO glass network former₂Addition to glass to replace P₂O₅The glass cannot cause great change of the refractive index and the dispersion, but if the content of the glass exceeds 10 percent, the temperature coefficient of the refractive index of the glass is rapidly increased, and the devitrification resistance of the glass is reduced. Thus, SiO₂The content of (b) is limited to 0 to 10%, preferably 0 to 8%, more preferably 0 to 5%.

In some embodiments of the invention, the SiO₂+B₂O₃And P₂O₅To a certain extent determines P₂O₅Structural state in glass, and P₂O₅The structural state of (A) has a great influence on two indexes of the glass, namely the temperature coefficient of the refractive index and the chemical stability. Further, when SiO₂+B₂O₃And P₂O₅Ratio of (SiO)₂+B₂O₃)/P₂O₅When the refractive index temperature coefficient is more than 0.5, the refractive index temperature coefficient of the glass is rapidly increased, and the design requirement cannot be met; if (SiO)₂+B₂O₃)/P₂O₅When the glass content is less than 0.1, the water resistance of the glass is rapidly lowered, and the use requirements under severe conditions cannot be met. On the other hand, for production, if (SiO)₂+B₂O₃)/P₂O₅The value of (A) is less than 0.1, the volatilization of the glass is increased during the molding process, so that the change of the refractive index and the Abbe number of the glass is large, and the design requirement cannot be met; the high-temperature viscosity of the glass is small, and the glass is easy to generate stripes below C level in the glass, so that the glass cannot be applied to an imaging system with higher requirements. Thus, in the present invention (SiO)₂+B₂O₃)/P₂O₅The value of (b) is 0.1 to 0.5, preferably 0.15 to 0.45, and more preferably 0.2 to 0.4.

Nb₂O₅The glass is an important component of the glass, and the refractive index of the glass can be rapidly improved by adding the glass into the glass, so that the glass realizes the performance of high refractive index and high dispersion. However, if the content exceeds 45%, the devitrification resistance of the glass is drastically lowered, and more seriously, Nb₂O₅The glass has strong aggregation effect, and when the content exceeds 45 percent, the temperature coefficient of the refractive index of the glass can be rapidly increased, which is contrary to the aim of reducing the temperature coefficient of the refractive index of the glass; if the content is less than 10%, the refractive index and dispersion of the glass do not meet the design requirements, and the chemical stability, particularly the water resistance, of the glass is lowered. Thus, Nb₂O₅The content of (B) is limited to 10 to 45%, preferably 15 to 45%, more preferably 20 to 43%.

To at Nb₂O₅The glass can maintain better anti-devitrification performance even under the condition of higher content, and the inventor researches and discovers that proper amount of Gd is added₂O₃、Y₂O₃、Al₂O₃、TiO₂One or more of the components can improve the devitrification resistance of the glass.

Specifically, Gd₂O₃Effect on refractive index and Dispersion with Nb₂O₅Similarly, when the content is more than 8%, the temperature coefficient of refractive index of the glass rapidly increases, the cost rapidly increases, and the devitrification resistance of the glass is rather deteriorated, so that Gd₂O₃The content of (b) is limited to 0 to 8%, preferably 0 to 6%, more preferably 0 to 4%.

Y₂O₃Additive to glassSubstitute for Nb in glass₂O₅The refractive index and the dispersion of the glass cannot be greatly changed, but if the content of the glass exceeds 5 percent, the temperature coefficient of the refractive index of the glass is rapidly increased, and the devitrification resistance of the glass is reduced. Thus, Y₂O₃The content of (B) is limited to 0 to 5%, preferably 0 to 4%, more preferably 0 to 3%.

Al₂O₃The additive is added into the glass, so that the devitrification resistance of the glass can be improved, and the capability of the molten glass to corrode crucible materials can be reduced. However, if the amount of the additive is more than 3%, the temperature coefficient of the refractive index of the glass increases, the melting property of the glass decreases, and the refractive index also rapidly decreases. Thus, Al₂O₃The content of (b) is limited to 3% or less, preferably 2% or less, and more preferably 1% or less.

TiO₂The glass can improve the sunlight-resistant stability of the glass when added into the glass, and is particularly important for the long-term exposure of the vehicle-mounted lens in strong ultraviolet environments such as plateaus and the like. In addition, a small amount of TiO₂Can improve the devitrification resistance of the glass, but TiO₂This is detrimental to the reduction of the temperature coefficient of refraction for the bulk glass. After a lot of experiments, the inventor finds that if the content of the glass exceeds 15%, the temperature coefficient of the refractive index of the glass cannot meet the design requirement. Thus, TiO in the present invention₂The content is 0 to 15%, preferably 0 to 12%, more preferably 0 to 10%.

After a great deal of experimental research by the inventor, Nb is found₂O₅And TiO₂Simultaneous use of TiO rather than separate use of TiO₂The effect of improving the sunlight-resistant stability of the glass is more obvious. However, when TiO₂And Nb₂O₅Ratio of (3) TiO₂/Nb₂O₅Above 1, the solar stability of the glass is no longer improved, but the temperature coefficient of refractive index rises more rapidly, contrary to the goal of obtaining a lower temperature coefficient of refractive index. Thus, in some embodiments of the invention, to obtain a glass with a lower temperature coefficient of refractive index and strong stability against sunlight, TiO is used₂/Nb₂O₅The value of (b) is 1 or less, preferably 0.8 or less, more preferably 0.5 or less.

BaO, CaO, SrO and MgO are alkaline earth metal oxides, and when the BaO, the CaO, the SrO and the MgO are added into glass, the refractive index and the dispersion of the glass can be adjusted, the stability of the glass is enhanced, and the devitrification resistance of the glass is improved. The common technical literature recognizes that the role of oxides of the same family in such glasses is essentially the same. However, the inventors have found through a large number of experiments that the effects of the above alkaline earth oxides are very different in temperature coefficient of refractive index, chemical stability and devitrification resistance, which are most important properties of the glass of the present system.

BaO has the strongest capacity of reducing the temperature coefficient of the refractive index of the glass, but if the content of the BaO exceeds 20 percent, the chemical stability, particularly the water resistance of the glass is rapidly reduced, and the devitrification resistance of the glass is also rapidly reduced. Therefore, the content of BaO is limited to 0 to 20%, preferably 0 to 16%, and more preferably 0 to 13%.

SrO is more than CaO but less than BaO in the temperature coefficient of refractive index, and the ability of the SrO to lower the temperature coefficient of refractive index of the glass is less than BaO in the chemical stability of the glass, and if the content of SrO exceeds 10%, the devitrification resistance of the glass is rather deteriorated rapidly, and the temperature coefficient of refractive index of the glass is rapidly increased, so that the content of SrO is 10% or less, preferably 0 to 8%, and more preferably 0 to 6%.

In the glass of the present invention, CaO is the weakest of alkaline earth oxides of CaO, BaO and SrO in terms of its ability to deteriorate water resistance, and therefore, CaO may be added in an appropriate amount from the viewpoint of improving water resistance of the glass, and the content of CaO in the present invention is limited to 0 to 25%, preferably 0 to 20%, and more preferably 0 to 15%. CaO has the ability to lower the temperature coefficient of refractive index of the glass less than BaO and SrO, and therefore it is preferred in some embodiments not to add CaO only from the viewpoint of lowering the temperature coefficient of refractive index.

For the system glass of the invention, MgO is not beneficial to reducing the temperature coefficient of the refractive index of the glass, but the water resistance and the stability of the glass can be improved by adding a proper amount of MgO. If the content of MgO exceeds 5%, the temperature coefficient of the refractive index of the glass does not meet the design requirement, and the devitrification resistance of the glass is rapidly reduced. Therefore, the content of MgO is limited to 5% or less, preferably 3% or less, and MgO is not added more preferably.

The inventor researches and discovers that when the three alkaline earth oxides of BaO, CaO and SrO are added, the complex synergistic effect of the glass occurs, and the performance does not change linearly with the addition of a single substance. In some embodiments of the present invention, when the CaO/(BaO + SrO) value exceeds 0.5, although the chemical stability of the glass is improved to some extent, the temperature coefficient of refractive index of the glass rapidly increases and the devitrification resistance of the glass rapidly decreases, so that the CaO/(BaO + SrO) value is 0 to 0.5, preferably 0 to 0.4, and more preferably 0 to 0.3.

In the main body glass, in order to obtain a lower temperature coefficient of refractive index, it is preferable that the content of BaO is not less than CaO, more preferably that the content of SrO is not less than CaO, and still more preferably that the content of BaO is not less than SrO.

Li₂O、K₂O、Na₂O belongs to alkali metal oxide, and the addition of proper amount can reduce the temperature coefficient of the refractive index of the glass, but the chemical stability and the anti-devitrification performance of the glass are rapidly reduced. The inventor finds out through a large number of experimental researches that:

1) in the glass of the system of the invention, the temperature coefficient of refractive index of the glass does not linearly decrease along with the increase of the alkali metal oxide, but the temperature coefficient of refractive index does not decrease after reaching an extreme value, but the anti-devitrification performance of the glass is sharply deteriorated by continuously adding the alkali metal oxide at the extreme value. In the present invention, Li₂O、K₂O and Na₂Sum of contents of O Li₂O+K₂O+Na₂If the value of O exceeds 35%, the temperature coefficient of refractive index of the glass is not lowered, and the devitrification resistance and the water resistance are drastically lowered.

From the production point of view, it is desirable that the lower the high-temperature viscosity at the time of clarification, the more advantageous the discharge of bubbles, and therefore, when the temperature coefficient of refractive index, water resistance and devitrification resistance of the glass meet the design requirements, the alkali metal oxide may be added in an amount of not more than 35% to raise the high-temperature viscosity of the glass and raise the level of the bubble degree of the glass at the time of mass production. Thus, Li₂O+K₂O+Na₂The total amount of O is controlled to be 35% or less,preferably 5 to 30%, more preferably 5 to 25%.

2) When all three alkali metal oxides coexist, a complex synergistic effect is generated if Li₂O/(K₂O+Na₂O) is more than 0.5, the devitrification resistance and chemical stability of the glass are drastically reduced, and the temperature coefficient of refractive index of the glass is substantially unchanged. Thus, Li₂O/(K₂O+Na₂O) is 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, the temperature coefficient of refractive index of the glass decreases, and the devitrification resistance and chemical stability decrease little.

From the viewpoint of lowering temperature coefficient of refractive index, K₂O and Na₂O is stronger and Li₂O times; from the viewpoint of destroying the chemical stability of the glass, K₂O and Na₂O is stronger and Li₂O times; li in terms of resistance to devitrification which deteriorates the glass₂Strongest O, K₂O and Na₂And O times. Therefore, in order to obtain a temperature coefficient of refractive index, chemical stability and anti-devitrification performance that satisfy the design expectations, how to select an appropriate kind and an appropriate amount of alkali metal oxide requires extensive experimental studies to determine. If Na₂The content of O exceeds 15%, and the devitrification resistance and chemical stability of the glass are sharply reduced, so that the content thereof is limited to 0 to 15%, preferably 2 to 12%, more preferably 4 to 10%. If K₂The content of O is higher than 25%, and the anti-crystallization performance and the chemical stability of the glass are rapidly reduced, so that the content is limited to 0-25%, preferably 3-20%, and more preferably 5-15%. Li₂When the content of O exceeds 5%, the devitrification resistance of the glass rapidly decreases, so that the content is 5% or less, preferably 3% or less, more preferably no Li is added₂O。

In some embodiments of the invention, Na in the glass₂O and K₂The proportion of O is greatly correlated with the bubble degree and water resistance of the glass. Further, when Na is contained₂O/K₂When the value of O is more than 1.5, the water resistance of the glass is sharply reduced; when Na is present₂O/K₂When the value of O is less than 0.1, the bubble degree of the glass rapidly decreases. Due to the fact thatThis is Na₂O/K₂The value of O is 0.1 to 1.5, preferably 0.2 to 1.2, and more preferably 0.3 to 1.0.

In some embodiments of the invention, the total content of BaO, SrO, CaO and Nb₂O₅、Gd₂O₃、Y₂O₃The ratio of the total content of (A) has a large relationship with the temperature coefficient of refractive index, devitrification resistance and water resistance of the glass. Further, when (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) When the value of (A) is more than 0.5, the temperature coefficient of refractive index of the glass is not lowered any more, and the water resistance and devitrification resistance of the glass are lowered. Therefore, to obtain glass with low temperature coefficient of refractive index, water resistance meeting design requirements and good devitrification resistance, (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) The value of (b) is 0 to 0.5, preferably 0 to 0.4, and more preferably 0 to 0.3.

In the glass of the present invention, BaO and Nb₂O₅The ratio of the contents of (A) has a large correlation with the temperature coefficient of refractive index of the glass and the water resistance and devitrification resistance of the glass. Further, when BaO, Nb₂O₅Ratio of (BaO)/(Nb)₂O₅When the glass refractive index is more than 0.5, the temperature coefficient of refractive index of the glass is not decreased, but the water resistance and devitrification resistance of the glass are sharply decreased. Thus, BaO/Nb₂O₅The value of (b) is 0 to 0.5, preferably 0 to 0.4, and more preferably 0 to 0.3.

The inventors have found that, in some embodiments of the invention, (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) The value of (A) is strongly correlated with the temperature coefficient of refractive index of the glass. Further, when (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) When the value of (A) is more than 1.0, the chemical stability and the devitrification resistance of the glass are slightly improved, but the temperature coefficient of the refractive index of the glass is sharply increased, and the design requirement cannot be met. Thus, (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Is less than 1.0, preferably less than 0.8, more preferably less than 0.6.

In some embodiments of the invention, 0-1% Sb is added₂O₃、SnO₂SnO and CeO₂One or more components of the glass can be used as a clarifying agent to improve the clarifying effect of the glass. However, the invention has reasonable formula design, good clarification effect and excellent bubble degree, so that 0-0.5% of clarifier is preferably added, 0-0.1% of clarifier is more preferably added, and no clarifier is further preferably introduced.

< component which should not be contained >

In the glass of the present invention, even when a small amount of oxides of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo is contained singly or in combination, the glass is colored and absorbs at a specific wavelength in the visible light region, thereby impairing the property of the present invention to improve the effect of visible light transmittance.

In recent years, oxides of Th, Cd, Tl, Os, Be, and Se tend to Be used as harmful chemical substances in a controlled manner, 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 pollutionDyed materials.

The "no incorporation", "no inclusion", "no addition" and "0%" described herein mean that the compound, molecule, element or the like is not intentionally added as a raw material to the optical glass of the present invention; however, it is within the scope of the present invention that certain impurities or components which are not intentionally added may be present as raw materials and/or equipment for producing the optical glass and may be contained in the final optical glass in small or trace amounts.

The performance of the optical glass of the present invention will be described below.

< refractive index and Abbe number >

Refractive index (n) of optical glass_d) And Abbe number (v)_d) The test was carried out according to the method specified in GB/T7962.1-2010.

Refractive index (n) of the optical glass of the present invention_d) 1.73 to 1.81, preferably 1.74 to 1.80, more preferably 1.75 to 1.79; abbe number (v)_d) 20 to 30, preferably 21 to 28, and more preferably 22 to 26.

< stability against Water action >

Stability of optical glass to Water action (D)_W) (powder method) the test was carried out according to the method prescribed in GB/T17129.

Stability to Water action of the optical glass of the invention (D)_W) Is 3 or more, preferably 2 or more, and more preferably 1.

< temperature coefficient of refractive index >

The temperature coefficient of refractive index (dn/dt) of optical glass was measured according to the method specified in GB/T7962.4-2010, and the temperature coefficient of refractive index (d-line dn/dt relative (10)) was measured in the range of 40 to 60 ℃^-6/℃))。

The temperature coefficient of refractive index (dn/dt) of the optical glass of the present invention is-2X 10^-6Lower than/° C, preferably-2.5X 10^-6Less than or equal to/° C, more preferably-3.0X 10^-6Not more than 4.0X 10 ℃ C, preferably not more than^-6Below/° c.

< resistance to devitrification >

Cutting the sample glass into 20 × 20 × 10mm, and placing at temperature T_gAnd (3) preserving the heat in a muffle furnace at +230 ℃ for 30 minutes, taking out the muffle furnace, putting the muffle furnace into heat preservation cotton, slowly cooling the muffle furnace, and observing whether obvious crystallization exists on the surface. The surface without obvious crystallization in the invention means that: the surface has no crystallization spots or crystallization spots, but the area of the surface accounts for less than 5 percent of the whole area and the crystallization depth does not exceed 0.5 mm. If the glass sample has no obvious crystallization, the crystallization resistance of the glass is excellent.

< degree of striae >

The degree of striae of the glass of the present invention was measured according to the method specified in MLL-G-174B. The method is that a fringe instrument composed of a point light source and a lens is used for comparing and checking with a standard sample from the direction of most easily seeing the fringes, the 4 grades are respectively A, B, C, D grades, A grade is that under the specified detection condition, A grade is that no visible fringes exist under the specified detection condition, B grade is that under the specified detection condition, fine and scattered fringes exist, C grade is that under the specified detection condition, slight parallel fringes do not exist, and D grade is that under the specified detection condition, coarse fringes exist.

The optical glass of the present invention has a striae of class C or more, preferably class B or more, and more preferably class a.

[ production method ]

The method for manufacturing the optical glass comprises the following steps: the glass is produced by adopting conventional raw materials and conventional processes, carbonate, nitrate, sulfate, hydroxide, oxide and the like are used as raw materials, the materials are mixed according to a conventional method, the mixed furnace burden is put into a smelting furnace at 1100-1250 ℃ for smelting, and after clarification, stirring and homogenization, homogeneous molten glass without bubbles and undissolved substances is obtained, and the molten glass is cast in a mold and annealed. Those skilled in the art can appropriately select the raw materials, the process method and the process parameters according to the actual needs.

Glass preform and optical element

The glass preform can be produced from the optical glass produced by, for example, grinding or press molding such as reheat press molding or precision press molding. That is, the glass preform may be produced by machining the optical glass by grinding, polishing, or the like, or by producing a preform for press molding from the optical glass, subjecting the preform to reheat press molding, and then polishing, or by precision press molding the preform obtained by polishing.

It should be noted that the means for producing the glass preform is not limited to the above means. As described above, the optical glass of the present invention is useful for various optical elements and optical designs, and among them, it is particularly preferable to form a preform from the optical glass of the present invention, and use the preform for reheat press forming, precision press forming, or the like to produce optical elements such as lenses, prisms, or the like.

The glass preform of the present invention and the optical element are each formed of the above-described optical glass of the present invention. The glass 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.

[ optical instruments ]

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

The optical glass has the properties of excellent chemical stability, lower refractive index temperature coefficient and the like, and is particularly suitable for being applied to the fields of vehicle-mounted monitoring and security protection and the like.

Examples

< example of optical glass >

In order to further clarify the explanation and explanation of the technical solution of the present invention, the following non-limiting examples are provided.

In this example, optical glasses having optical glass compositions shown in tables 2 to 3 were obtained by the above-mentioned method for producing optical glasses. In addition, the measurement of each glass was carried out by the test method described in the present inventionThe results of the measurements are shown in tables 2 to 3. In tables 2 to 3, (SiO)₂+B₂O₃)/P₂O₅Is denoted by K1; TiO 2₂/Nb₂O₅Is denoted by K2; li₂O+K₂O+Na₂The total amount of O is represented by K3; li₂O/(K₂O+Na₂O) is represented by K4; na (Na)₂O/K₂The value of O is represented by K5; (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) Is denoted by K6; BaO/Nb₂O₃Is denoted by K7; (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Is denoted by K8. In the test of the crystallization resistance, no obvious crystallization is marked as 'A', and obvious crystallization is marked as 'B'.

TABLE 2

TABLE 3

< glass preform example >

Various lenses such as a concave meniscus lens, a convex meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens and a plano-concave lens, and preforms such as prisms were produced from the glasses obtained in examples 1 to 20 of optical glass by means of polishing or press molding such as reheat press molding and precision press molding.

< optical element example >

The preforms obtained in the above examples of glass preforms were annealed to reduce the deformation in the glass and to fine-tune the optical properties such as refractive index to desired values.

Next, each preform is ground and polished to produce various lenses such as a concave meniscus lens, a convex meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens, and a plano-concave lens, and prisms. The surface of the resulting optical element may be coated with an antireflection film.

< optical Instrument example >

The optical element obtained by the above-described optical element embodiment is used for, for example, imaging devices, sensors, microscopes, medical technologies, digital projection, communications, optical communication technologies/information transmission, optics/lighting in the automobile field, photolithography, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices including such circuits and chips, or for image pickup devices and apparatuses in the vehicle-mounted field, by forming an optical component or an optical assembly by using one or more optical elements through optical design.

Claims

1. Optical glass, characterized in that its components, expressed in weight percent, contain: p₂O₅：4～30％；BaO：0～20％；Nb₂O₅：10～45％；Li₂O+K₂O+Na₂O: 0 to 35 percent; wherein BaO/Nb₂O₅0 to 0.5.

2. The optical glass according to claim 1, wherein the composition further comprises, in weight percent: SiO 2₂：0～10％；B₂O₃：0～10％；Gd₂O₃：0～8％；Y₂O₃：0～5％；Al₂O₃：0～3％；TiO₂: 0 to 15 percent; MgO: 0 to 5 percent; CaO: 0 to 25 percent; SrO: 0 to 10 percent; a clarifying agent: 0 to 1 percent.

3. Optical glass, characterized in that its composition, expressed in weight percentage, is represented by P₂O₅：4～30％；Nb₂O₅：10～45％；Li₂O+K₂O+Na₂O：0～35％；SiO₂：0～10％；B₂O₃：0～10％；Gd₂O₃：0～8％；Y₂O₃：0～5％；Al₂O₃：0～3％；TiO₂: 0 to 15 percent; MgO: 0 to 5 percent; CaO: 0 to 25 percent; SrO: 0 to 10 percent; BaO: 0 to 20 percent; a clarifying agent: 0 to 1% of a composition of BaO/Nb₂O₅0 to 0.5.

4. An optical glass characterized by containing P₂O₅、Nb₂O₅Alkaline earth metal oxides and alkali metal oxides, the components of which are expressed in weight percent, wherein BaO/Nb₂O₅0 to 0.5, Li₂O/(K₂O+Na₂O) is 0.5 or less, and the refractive index n of the optical glass_d1.73 to 1.81, Abbe number v_d20 to 30, and a temperature coefficient of refractive index dn/dt of-2 x 10^-6Below/° c.

5. An optical glass according to claim 4, characterised in that it comprises, in percentages by weight: p₂O₅: 4-30%; and/or Nb₂O₅: 10-45%; and/or Li₂O+K₂O+Na₂O: 0 to 35 percent; and/or SiO₂: 0 to 10 percent; and/or B₂O₃: 0 to 10 percent; and/or Gd₂O₃: 0-8%; and/or Y₂O₃: 0 to 5 percent; and/or Al₂O₃: 0 to 3 percent; and/or TiO₂: 0 to 15 percent; and/or MgO: 0 to 5 percent; and/or CaO: 0 to 25 percent; and/or SrO: 0 to 10 percent; and/or BaO: 0 to 20 percent; and/or a clarifying agent: 0 to 1 percent.

6. An optical glass according to any one of claims 1 to 5, wherein the composition is expressed in weight percent, wherein: p₂O₅：10～30％；And/or Nb₂O₅: 15-45%; and/or Li₂O+K₂O+Na₂O: 5-30%; and/or SiO₂: 0-8%; and/or B₂O₃: 1-9%; and/or Gd₂O₃: 0-6%; and/or Y₂O₃: 0 to 4 percent; and/or Al₂O₃: 0-2%; and/or TiO₂: 0 to 12 percent; and/or MgO: 0 to 3 percent; and/or CaO: 0 to 20 percent; and/or SrO: 0-8%; and/or BaO: 0 to 16 percent; and/or a clarifying agent: 0 to 0.5 percent.

7. An optical glass according to any one of claims 1 to 5, wherein the composition is expressed in weight percent, wherein: p₂O₅: 15-25%; and/or Nb₂O₅: 20-43%; and/or Li₂O+K₂O+Na₂O: 5-25%; and/or SiO₂: 0 to 5 percent; and/or B₂O₃: 2-8%; and/or Gd₂O₃: 0 to 4 percent; and/or Y₂O₃: 0 to 3 percent; and/or Al₂O₃: 0 to 1 percent; and/or TiO₂: 0 to 10 percent; and/or CaO: 0 to 15 percent; and/or SrO: 0-6%; and/or BaO: 0 to 13 percent; and/or a clarifying agent: 0 to 0.1%.

8. An optical glass according to any one of claims 1 to 5, characterised in that its composition, expressed in weight percentage, is BaO/Nb₂O₅0 to 0.4, preferably BaO/Nb₂O₅0 to 0.3.

9. An optical glass according to any of claims 1 to 5, characterised in that its composition is expressed in weight percentage in which (SiO)₂+B₂O₃)/P₂O₅0.1 to 0.5, preferably (SiO)₂+B₂O₃)/P₂O₅0.15 to 0.45, more preferably (SiO)₂+B₂O₃)/P₂O₅Is 0.2 to 0.4。

10. An optical glass according to any one of claims 1 to 5, characterised in that its components, expressed in weight percentage, are TiO₂/Nb₂O₅Has a value of 1 or less, preferably TiO₂/Nb₂O₅A value of (2) is 0.8 or less, and TiO is more preferable₂/Nb₂O₅The value of (A) is 0.5 or less.

11. An optical glass according to any of claims 1 to 5, characterised in that its composition, expressed in weight percent, is such that CaO/(BaO + SrO) is from 0 to 0.5, preferably CaO/(BaO + SrO) is from 0 to 0.4, more preferably CaO/(BaO + SrO) is from 0 to 0.3.

12. An optical glass according to any one of claims 1 to 5, characterised in that its components, expressed in weight percentage, are Li₂O/(K₂O+Na₂O) is 0.5 or less, preferably Li₂O/(K₂O+Na₂O) is 0.4 or less, more preferably Li₂O/(K₂O+Na₂O) is 0.3 or less.

13. An optical glass according to any one of claims 1 to 5, characterised in that its composition is expressed in weight percentage by the sum of Na₂O/K₂O is 0.1 to 1.5, preferably Na₂O/K₂O is 0.2 to 1.2, more preferably Na₂O/K₂O is 0.3 to 1.0.

14. An optical glass according to any one of claims 1 to 5, wherein the composition is, in weight percent, (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.5, preferably (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.4, more preferably (BaO + SrO + CaO)/(Nb)₂O₅+Gd₂O₃+Y₂O₃) 0 to 0.3.

15. An optical glass according to any one of claims 1 to 5, wherein the composition is, in weight percent, (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 1.0, preferably (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 0.8, more preferably (CaO + BaO + SrO)/(Al)₂O₃+TiO₂) Less than 0.6.

16. An optical glass according to any one of claims 1 to 5, characterised in that its composition, expressed in weight percentage, is Na₂O: 0 to 15%, preferably Na₂O: 2 to 12%, more preferably Na₂O: 4-10%; and/or K₂O: 0 to 25%, preferably K₂O: 3 to 20%, more preferably K₂O: 5-15%; and/or Li₂O: 0 to 5%, preferably Li₂O: 0 to 3%, more preferably no Li is added₂O。

17. An optical glass according to any of claims 1 to 5, characterised in that its composition, expressed in weight percentage, is such that the content of BaO is equal to or greater than the content of CaO, preferably the content of SrO is equal to or greater than the content of CaO.

18. The optical glass according to any one of claims 1 to 5, wherein the refractive index n of the optical glass_d1.73 to 1.81, preferably 1.74 to 1.80, more preferably 1.75 to 1.79; abbe number v_d20 to 30, preferably 21 to 28, and more preferably 22 to 26.

19. The optical glass according to any one of claims 1 to 5, wherein the optical glass has a temperature coefficient of refractive index dn/dt of-2 x 10 at 40 to 60 ℃^-6Lower than/° C, preferably-2.5X 10^-6Less than or equal to/° C, more preferably-3.0X 10^-6Below/° c, further oneThe step is preferably-4.0X 10^-6Below/° c.

20. The optical glass according to any one of claims 1 to 5, wherein the optical glass has a stability to water action D_WIs 3 or more, preferably 2 or more, more preferably 1; and/or the degree of streaking is at least level C, preferably at least level B, more preferably at level A.

21. A glass preform made of the optical glass according to any one of claims 1 to 20.

22. An optical element produced from the optical glass according to any one of claims 1 to 20 or the glass preform according to claim 21.

23. An optical device comprising the optical glass according to any one of claims 1 to 20, or comprising the optical element according to claim 22.