CN107963808B

CN107963808B - Glass composition and chemically tempered glass

Info

Publication number: CN107963808B
Application number: CN201711328926.3A
Authority: CN
Inventors: 李丹; 陈雪梅; 赖德光
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2017-12-13
Filing date: 2017-12-13
Publication date: 2022-01-25
Anticipated expiration: 2037-12-13
Also published as: CN107963808A

Abstract

The present invention provides a glass composition suitable for chemical tempering having a refractive index of 1.68-1.77 and an abbe number of 25-34. Glass composition consisting of, in percentages by weight: SiO 2: 20 to 40 percent; ZrO 2: 1 to 12 percent; TiO 2: 10 to 28 percent; nb2O 5: 2 to 15 percent; na 2O: 4 to 25 percent; la2O 3: 3 to 20 percent. According to the invention, through reasonable component proportion, the glass composition is suitable for chemical toughening while having high refractive index, and meets the use requirements of vehicle-mounted equipment and the like.

Description

Glass composition and chemically tempered glass

Technical Field

The invention relates to a glass composition, in particular to a glass composition with a refractive index ranging from 1.68 to 1.77 and an Abbe number ranging from 25 to 34 and chemically tempered glass obtained by tempering the glass composition.

Background

With the development of economy, the global automobile sales keeps increasing trend all the time, the market of the vehicle-mounted camera is rapidly increased for a long time, and the market prospect of the vehicle-mounted camera is wide. In an in-vehicle camera, high definition of image quality and a wide angle of an imaging angle are required for securing safety and improving recording performance. Conventional vehicle-mounted imaging apparatuses employ an optical element made of a plastic material or a low-refractive glass material, which is difficult to satisfy high definition of image quality and a wide angle of imaging angle, and therefore, in an imaging lens of a camera mounted on a vehicle, it is considered to be configured using a high-refractive optical glass.

Further, unlike the imaging lens of a general camera, the imaging lens mounted on the vehicle-mounted camera may be damaged or eroded by impact or wind pressure accompanying the driving of the vehicle and flying dust, and particularly when the imaging angle is enlarged, the first surface exposure area of the imaging lens becomes large, which may be influenced by the environment. Therefore, there are considerable demands on the strength and impact resistance of optical glass, and chemical tempering is a very effective method for improving the strength and impact resistance of glass.

The method of chemically changing the surface composition to increase the mechanical strength and thermal stability of the glass is called chemical tempering, also called ion exchange. According to the theory of network structure of glassThe glass is composed of a disordered three-dimensional network consisting of B³⁺、Si⁴⁺、Al³⁺、P⁵⁺And oxygen ions, and the alkali metal ions and the alkaline earth metal ions fill the network gaps, wherein the alkali metal ions are very active and are easy to move. Chemical tempering is to change the components of the glass surface based on natural diffusion and mutual diffusion, reduce the coefficient of thermal expansion of the surface, thereby forming a surface pressure layer with a certain thickness and improving the surface strength and the shock resistance of the glass.

In order to satisfy chemical tempering, the glass component must necessarily contain a certain amount of Li⁺Or Na⁺Only then can ion exchange take place. Conventional high refractive index glasses, in view of higher refractive index and glass forming properties, contain no or little Li⁺Or Na⁺For example, CN1252391A discloses an optical glass having a refractive index of 1.64 to 1.86, the composition of which contains only 0 to 1% of Na₂O, this glass is not suitable for chemical tempering.

The chemical toughened glass formula adopted in the current market is concentrated on lithium-aluminum-silicon, sodium-aluminum-silicon and sodium-calcium-silicon glass, and the glass contains a large amount of SiO₂、Al₂O₃And the like, and the refractive index is low, so that the requirement of high refractive index for vehicle-mounted use cannot be met. For example, CN104591536A discloses a glass which can be chemically tempered, but which has a composition of SiO₂And Al₂O₃Has a total content of more than 70 mol% and a low refractive index.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a glass composition suitable for chemical tempering, which has a refractive index of 1.68-1.77 and an Abbe number of 25-34

The technical scheme adopted by the invention for solving the technical problem is as follows: glass composition consisting of, in percentages by weight: SiO2₂：20-40％；ZrO₂：1-12％；TiO₂：10-28％；Nb₂O₅：2-15％；Na₂O：4-25％；La₂O₃：3-20％。

Further, alsoComprises the following components: ZnO: 0 to 10 percent; al (Al)₂O₃：0-10％；Li₂O：0-10％；K₂O：0-5％；MgO：0-10％；CaO：0-10％；SrO：0-10％；BaO：0-10％；B₂O₃：0-15％；WO₃：0-10％；Gd₂O₃：0-10％；Y₂O₃：0-10％；Yb₂O₃：0-10％；Sb₂O₃：0-1％。

Glass composition having the composition, expressed in weight percentages, as: SiO2₂：20-40％；ZrO₂：1-12％；TiO₂：10-28％；Nb₂O₅：2-15％；Na₂O：4-25％；La₂O₃：3-20％；ZnO：0-10％；Al₂O₃：0-10％；Li₂O：0-10％；K₂O：0-5％；MgO：0-10％；CaO：0-10％；SrO：0-10％；BaO：0-10％；B₂O₃：0-15％；WO₃：0-10％；Gd₂O₃：0-10％；Y₂O₃：0-10％；Yb₂O₃：0-10％；Sb₂O₃：0-1％。

Further, wherein SiO₂: 23 to 38 percent; and/or ZrO₂: 3 to 11 percent; and/or La₂O₃: 5 to 18 percent; and/or ZnO: 0 to 8 percent; and/or TiO₂: 12 to 25 percent; and/or Nb₂O₅: 4 to 12 percent; and/or Na₂O: 7 to 20 percent; and/or Al₂O₃: 0 to 5 percent; and/or Li₂O: 0 to 5 percent; and/or WO₃: 0 to 5 percent; and/or MgO: 0 to 5 percent; and/or CaO: 0 to 5 percent; and/or SrO: 0 to 5 percent; and/or BaO: 0 to 5 percent; and/or B₂O₃: 0 to 10 percent; and/or Gd₂O₃: 0 to 5 percent; and/or Y₂O₃: 0 to 5 percent; and/or Yb₂O₃: 0 to 5 percent; and/or Sb₂O₃：0-0.5％。

Further, wherein (Nb)₂O₅+TiO₂)/La₂O₃Is 1 to 6; and/or BaO + SrO + CaO + MgO is 0-12%; and/or BaO + SrO is 0-10%; and/or Li₂O+Na₂O+K₂O is 7 to 27 percent; and/or Li₂O/(Li₂O+Na₂O+K₂O) is 0.6 or less.

Further, wherein (Nb)₂O₅+TiO₂)/La₂O₃1.5-5.5; and/or Li₂O+Na₂O+K₂The content of O is 10-25%; and/or Li₂O/(Li₂O+Na₂O+K₂O) is 0.5 or less.

Further, wherein SiO₂: 25 to 35 percent; and/or TiO₂: 15 to 23 percent; and/or B₂O₃: 0 to 5 percent; and/or (Nb)₂O₅+TiO₂)/La₂O₃Is 2 to 5; and/or Li₂O/(Li₂O+Na₂O+K₂O) is 0.4 or less.

Further, no Gd is contained₂O₃And/or Yb₂O₃。

Further, the glass has a refractive index nd of 1.68 to 1.77, preferably 1.69 to 1.76; abbe number v_dFrom 25 to 34, preferably from 26 to 33.

Further, the glass has a glass transition temperature Tg of 600 ℃ or lower and is stable against acid action D_AIs 2 or more, preferably 1 type, and has water resistance stability (D)_W) Is 2 or more, preferably 1.

An optical preform made from the glass composition described above.

An optical element is produced by using the glass composition.

An optical device, which is made of the glass composition.

The chemically toughened glass is prepared by chemically toughening the glass composition.

Furthermore, the bending strength sigma is more than or equal to 550MPa, and the Knoop hardness H_k≥540×10⁷Pa; the impact strength is such that 32g of the steel ball does not break when dropped from a height of 300mm to the tempered glass, and is preferably 500mm or more, more preferably 600mm or more, and still more preferably 700mm or more.

The optical element is made of the chemically tempered glass.

The optical instrument is made of the chemically toughened glass.

The invention has the beneficial effects that: through reasonable component proportion, the glass composition is suitable for chemical toughening while having high refractive index, and meets the use requirements of vehicle-mounted equipment and the like.

Drawings

FIG. 1 is a schematic view showing the test of the bending strength of the chemically tempered glass of the present invention.

Detailed Description

Glass composition

The composition of the glass composition of the present invention will be described in detail below, and the content and total content of each glass component are expressed by weight percent unless otherwise specified. In the following description, when a value equal to or less than a predetermined value or a value equal to or greater than the predetermined value is mentioned, the predetermined value is also included.

[ As to essential and optional Components ]

SiO₂The network former oxide, which is an essential component of the glass of the present invention, is an essential component for enhancing the hardness of the glass and maintaining the glass-forming stability. When the content is less than 20%, on one hand, the hardness is reduced, and on the other hand, the requirement of glass forming stability is difficult to meet; when the content is more than 40%, the refractive index of the glass decreases, the melting property and the devitrification resistance deteriorate, and the glass transition temperature and the liquid phase temperature increase. Thus, SiO₂The content of (B) is in the range of 20 to 40%, preferably 23 to 38%, more preferably 25 to 35%.

In the invention, a small amount of B is added₂O₃The meltability of the glass can be increased. When B is present₂O₃When the content is 15% or more, the chemical stability of the glass is deteriorated and the devitrification resistance is deteriorated. Accordingly, in the optical glass of the present invention B₂O₃The content of (B) is 0 to 15%, preferably 0 to 10%, more preferably 0 to 5%.

Al₂O₃Can improve the chemical stability of the formed glass, and simultaneously, a small amount of Al₂O₃Can be beneficial to chemical steelHowever, when the content exceeds 10%, the refractive index of the glass decreases, and the meltability deteriorates. Thus, Al of the invention₂O₃The content of (B) is 0 to 10%, preferably 0 to 5%.

La₂O₃Is an essential component of the present invention, and can reduce the dispersion of the glass while increasing the refractive index of the glass, and is advantageous for obtaining a glass having a high abbe number. At the same time, La₂O₃The glass hardness and the impact resistance can be effectively improved. But too much La₂O₃If present, the devitrification property of the glass is deteriorated and the transition temperature of the glass is increased. Therefore, La in the present invention₂O₃The content of (B) is limited to 3 to 20%, preferably 5 to 18%.

Gd₂O₃Is helpful for increasing refractive index and reducing dispersion, and partially replaces La₂O₃Can improve the devitrification resistance and the chemical stability of the glass, but the expensive raw material price limits Gd₂O₃Use in glass. Thus, Gd₂O₃The content of (B) is 0 to 10%, preferably 0 to 5%, and more preferably not contained.

The glass of the invention may also incorporate Y₂O₃In order to improve the melting property and devitrification resistance of the glass, and to lower the upper limit temperature of devitrification of the glass to improve the chemical stability of the glass, if the content exceeds 10%, the stability and devitrification resistance of the glass are lowered. Thus, Y₂O₃The content is in the range of 0-10%, preferably in the range of 0-5%.

Yb₂O₃Also, a glass may be added with a component, and when the content exceeds 10%, the stability and devitrification resistance of the glass are lowered. Thus, Yb₂O₃The content range is defined as 0 to 10%, preferably 0 to 5%, and further preferably not incorporated.

TiO₂The glass has the effect of improving the refractive index of the glass, can participate in the formation of a glass network, and is an essential component in the invention because the atomic radius is small, the inhibition effect on ion exchange in the chemical toughening process is small while the refractive index of the glass is improved. But when the content thereof is too much,the transmittance of the glass in the short wavelength region in the visible light region decreases, and the glass tends to be colored. Thus, the TiO of the present invention₂The content of (B) is 10 to 28%, preferably 12 to 25%, and more preferably 15 to 23%.

Nb₂O₅Has the functions of improving the refractive index and dispersion of the glass, and simultaneously has the functions of improving the crystallization resistance and chemical stability of the glass. If the content is less than 2%, the above effects are not obvious; however, if the content exceeds 15%, the devitrification property and transmittance of the glass deteriorate. Thus, Nb₂O₅The content of (B) is in the range of 2 to 15%, preferably 4 to 12%.

WO₃The effect of increasing the refractive index is exhibited, but when the content exceeds 10%, the dispersion is remarkably increased, and the transmittance on the short wavelength side of the visible light region of the glass is decreased, so that the tendency of coloring is increased. Thus, the present invention WO₃The content of (B) is 0 to 10%, preferably 0 to 5%.

The mainstream technology for manufacturing the lens at present adopts a secondary compression method to manufacture a lens blank, and then the lens blank is polished to obtain a qualified glass lens. The "secondary press" processing technology of optical glass is that the blank glass is cut into small blocks, heated in furnace body to the temp. near the softening temp. of glass, then the glass is placed in mould, and pressurized under the action of external force to obtain proper lens shape. If the glass is devitrified in the process of secondary pressing, the pressed part can be scrapped. The inventors have found through diligent studies that La is a very important component of a phosphor₂O₃And (Nb)₂O₅+TiO₂) In a certain ratio therebetween, i.e. (Nb)₂O₅+TiO₂)/La₂O₃In the range of 1 to 6, it is possible to ensure that the glass is not devitrified when pressed into a mold, and (Nb)₂O₅+TiO₂)/La₂O₃The range is 1.5 to 5.5, and a more preferable range is 2 to 5.

ZrO₂The addition of the glass can improve the refractive index and hardness of the glass. Proper amount of ZrO₂When the glass is added, the devitrification resistance of the glass can be improved, and ion exchange in the chemical toughening process is facilitated. But when the content is less than 1%, the aboveThe effect is not obvious. If the content is more than 12%, the glass becomes difficult to melt, and inclusions in the glass and the transmittance of the glass are liable to be reduced, and the devitrification resistance of the glass is deteriorated. Thus, ZrO₂The content is 1-12%, preferably 3-11%.

ZnO can reduce the transition temperature of the glass, adjust the refractive index and dispersion of the glass, improve the anti-crystallization performance of the glass and improve the chemical stability of the glass. When the content of ZnO is too large, the devitrification resistance of the glass is lowered, and the high-temperature viscosity is small, which makes molding difficult. Therefore, the content of ZnO is limited to 0 to 10%, preferably 0 to 8%.

The introduction of BaO can improve the refractive index of the glass and the transmittance of the glass, but when the introduction is excessive, the hardness of the glass is sharply reduced, and the ion exchange in the toughening process is inhibited. Therefore, the content of BaO is 0 to 10%, preferably 0 to 5%.

CaO helps to increase the refractive index of the glass, and its substitution for a portion of BaO can increase the glass range. However, if CaO is added in an excessive amount, the devitrification resistance of the glass is deteriorated. Therefore, the CaO content is limited to 0 to 10%, preferably 0 to 5%.

The addition of SrO to glass can adjust the refractive index and abbe number of the glass, but if the addition amount is too large, the chemical stability and devitrification resistance of the glass are lowered, and at the same time, the ion exchange in the tempering process is suppressed, and the cost of the glass is increased. Therefore, the SrO content is limited to 0 to 10%, preferably 0 to 5%,

in the present invention, the melting property of the glass can be improved by introducing MgO, but when the content thereof exceeds 10%, the cost of the glass increases and the liquid phase temperature rises. Therefore, the MgO content in the present invention is 0 to 10%, preferably 0 to 5%.

BaO, SrO, CaO and MgO belong to alkaline earth metal oxides, which can adjust the refractive index and dispersion of the glass and reduce the high-temperature viscosity of the glass. However, when the amount is excessively added, chemical stability and devitrification resistance of the glass are remarkably deteriorated, and since the atomic radius of these substances is close to the atomic radius of Li or Na in chemical tempering, ion exchange in chemical tempering is relatively easily inhibited, the total amount of BaO + SrO + CaO + MgO of BaO, SrO, CaO and MgO is preferably in the range of 0 to 12%.

Among the four alkaline earth metal oxides of BaO, SrO, CaO and MgO, BaO and SrO are the most advantageous for improving the refractive index, but the radii of these oxides are the largest, and the effect of inhibiting ion exchange is comparatively the largest, and the total amount of BaO + SrO is preferably in the range of 0 to 10% in total.

Li₂O can be used as an ion exchange component in the chemical tempering process, has a fluxing action, can increase the high-temperature melting property of the glass, and can reduce the glass transition temperature, and if the content exceeds 10%, the chemical stability and processability of the glass are deteriorated, so that Li₂The content of O is 0-10%, preferably Li₂The content of O is 0-5%.

Na₂O is an essential component for ion exchange in the chemical toughening process, and when the content of O is lower than 4%, effective chemical toughening cannot be performed, so that the strength of the toughened glass is not improved; when the content thereof is more than 25%, the refractive index of the glass is remarkably decreased, and chemical stability and processability are deteriorated. Thus Na₂The content of O is in the range of 4 to 25%, preferably 7 to 20%.

K₂O has fluxing property and a small amount of K₂The presence of O can increase the rate of initial ion exchange. However, when the content exceeds 5%, it is not favorable for the improvement of refractive index and ion exchange in the chemical tempering process, so that the content is 0 to 5%.

In the glass of the invention, Li₂O、Na₂O and K₂Total content of O Li₂O+Na₂O+K₂O is preferably controlled to be 7-27% so as to be beneficial to improving the chemical toughening effect of the glass, effectively improve the stability and the melting property of the glass and reduce the transformation temperature. More preferably Li₂O+Na₂O+K₂The content of O is 10-25%.

The chemical tempering is Li⁺Or Na⁺Ion exchange with K + in solution, Li⁺And K⁺Exchange of (2) with respect to Na⁺And K⁺Exchange of (2) can cause the glass surface to beThe micro-cracks are easy to generate, and the strength and the shock resistance after the tempering are not improved. The inventors have made extensive studies to find that when Li is used₂Ratio of O content to total alkali metal oxide content Li₂O/(Li₂O+Na₂O+K₂O) of 0.6 or less is preferable because it is advantageous to obtain a glass excellent in chemical tempering, and Li is preferable₂O/(Li₂O+Na₂O+K₂O) is 0.5 or less, and more preferably 0.4 or less.

By adding small amounts of Sb₂O₃The component can improve the fining effect of the glass, but when Sb is used₂O₃When the content exceeds 1%, the glass tends to have a lowered fining property and the deterioration of the forming mold is promoted by its strong oxidizing action. Therefore, Sb is preferred in the present invention₂O₃The amount of (B) is 0 to 1%, more preferably 0 to 0.5%.

[ 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 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.

In recent years, cations of Pb, 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. Thus, the optical glass contains virtually no 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.

Next, the characteristics of the glass composition of the present invention will be described.

[ optical constants of glass compositions ]

The refractive index (nd) and Abbe number (. nu.) of the glass composition of the present invention_d) The test was carried out according to the method specified in GB/T7962.1-2010.

The glass composition is high-refractivity high-dispersion glass, and a lens made of the high-refractivity high-dispersion glass is combined with a lens made of high-refractivity low-dispersion glass in many cases and is used for chromatic aberration correction. The glass composition of the present invention has a glass refractive index (nd) in the range of 1.68 to 1.77, preferably in the range of 1.69 to 1.76; abbe number (v) of the glass of the invention_d) In the range of 25 to 34, preferably in the range of 26 to 33.

[ transition temperature of glass composition ]

The transition temperature (Tg) of the glass composition of the invention is measured according to the method specified in GB/T7962.16-2010.

The glass gradually changes from a solid state to a plastic state in a certain temperature interval. The transition temperature is a temperature corresponding to an intersection point where extensions of straight line portions of a low temperature region and a high temperature region of a glass sample, which is heated from room temperature to a sag temperature, intersect.

The glass according to the invention has a transition temperature (Tg) of 600 ℃ or less, preferably 590 ℃ or less.

[ chemical stability of glass composition ]

The ability of an optical element to resist the action of various aggressive media on its polished surface during manufacture and use is referred to as the chemical stability of the glass composition.

Stability to Water action of the glasses according to the invention D_W(powder method) stability against acid action D_AThe number of types (powder methods) is 2 or more, preferably 1 or more.

Stability to Water action D_W(powder method) according to GB/T17129 test method, calculated according to the following formula:

D_W＝(B-C)/(B-A)*100

in the formula: d_WPercent glass leached (%)

B-mass (g) of filter and sample

C-quality (g) of the filter and of the eroded sample

A-Filter Mass (g)

Stabilizing the glass against water by the calculated percentage of leaching D_WThe classification is 6 in the following table.

Stability against acid action D_A(powder method) according to GB/T17129 test method, calculated according to the following formula:

D_A＝(B-C)/(B-A)*100

in the formula: d_APercent glass leached (%)

B-mass (g) of filter and sample

C-quality (g) of the filter and of the eroded sample

A-Filter Mass (g)

Stabilizing the glass against acid by the calculated percent leaching D_AThe classification is 6 in the following table.

Categories	1	2	3	4	5	6
							Percentage leaching (D)_A)	＜0.20	0.20-0.35	0.35-0.65	0.65-1.20	1.20-2.20	>2.20

[ devitrification resistance of glass ]

Cutting the sample glass into the specification of 20 multiplied by 10mm, placing the sample glass into a muffle furnace with the temperature of 700 plus one temperature of 900 ℃ for heat preservation for 30 minutes, taking the sample glass out, placing the sample glass into heat preservation cotton for slow cooling, polishing the surface, and observing the crystallization condition under a microscope.

II, optical prefabricated member A and optical element B

Both the optical preform a and the optical element B of the present invention are formed of the above-described glass composition of the present invention. The optical prefabricated member A has the characteristics of high refractive index and high dispersion; the optical element B of the present invention has high refractive index and high dispersion characteristics, and can provide optical elements such as various lenses and prisms having high optical values at low cost.

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.

The lens can correct chromatic aberration by combining with a lens made of high-refractive-index low-dispersion glass, and is suitable as a lens for chromatic aberration correction. Further, the lens is also effective for the compactness of an optical system.

Since the prism has a high refractive index, when the prism is incorporated in an imaging optical system, the optical path is bent to a desired direction, whereby a compact and wide-angle optical system can be realized.

III, optical apparatus C

The optical element B formed of the glass composition of the present invention can be used for various types of optical instruments, and by forming an optical component or optical assembly using one or more optical elements B, it can be used for, for example, imaging devices, sensors, microscopes, medical technology, digital projection, communications, optical communication technology/information transmission, optics/illumination in the automotive field, lithography, steppers, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices including such circuits and chips.

The present invention relates to the use of optical components or optical assemblies produced using the above-described optical element B, which can be used, for example, in sensors, microscopes, medical technology, digital projection, communication, optical communication technology/information transmission, optics/illumination in the automotive field, lithography, steppers, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices comprising such circuits and chips.

IV, toughened glass

The glass composition of the present invention can be tempered by a salt bath furnace or the like, the obtained glass composition is cut or pressed into a predetermined shape, placed on an anticorrosive sample holder, and subjected to KNO₃And/or NaNO₃Ion exchange treatment is carried out for 4-8h in a salt bath at the temperature of 370-480 ℃.

The toughened glass of the invention has the following characteristics:

[ Knoop hardness ]

The Knoop hardness Hk is measured according to the test method specified in GB/T7962.18-2010.

The method adopts a quadrangular pyramid diamond pressure head with symmetrical edge angles of 172 degrees 30' and 130 degrees, applies a certain load to the pressure head to vertically press on a sample, removes the load after keeping for a certain time, observes and measures the length of an indentation diagonal on the sample by a microscope, and calculates the Hk hardness according to the following formula:

Hk＝1.4229F/d²

in the formula:

f represents a pressurizing load, N;

d represents the length of the long diagonal of the indentation, mm;

hk denotes Knoop hardness, 10⁷Pa。

The toughened glass of the invention has a Knoop hardness (Hk) of 540X 10⁷Pa or above.

[ bending Strength ]

Flexural strength was measured by a four-point method and the samples were 36X 29X 0.8mm flat sheets, as shown in FIG. 1. The sample was placed on two fulcrums A, B spaced 30mm apart, and the corresponding stress at break was the maximum bending stress F of the sample by loading the sample at C, D points in the center of the fulcrum. The four-point bending strength formula is as follows:

in the formula:

σ_(4.L): four-point bending strength (MPa);

l: the span (mm) between the two lower fulcrums;

l: upper load point spacing (mm);

f: maximum bending stress (N) at sample break;

w: the width of the sample;

t: the thickness of the sample.

The tempered glass of the present invention has a bending strength (σ) of 550MPa or more, preferably 580MPa or more, and more preferably 600MPa or more.

[ impact Strength ]

The impact strength is tested by adopting a high-altitude ball falling method, a sample is a flat sheet of 36 multiplied by 29 multiplied by 0.8mm, a steel ball with the mass of 32g vertically impacts the sample in a free falling mode from the height of 300mm, if the sample is intact after impact, the impact height is sequentially increased by 50mm for impact until the sample is broken, and the impact strength of the glass is measured by the final impact height. The final impact height of the tempered glass of the present invention is 500mm or more, preferably 600mm or more, and more preferably 700mm or more.

V, optical element D

The optical element D of the present invention is formed of the tempered glass of the present invention, has high refractive index and high dispersion characteristics, and can provide optical elements such as various lenses, prisms, glass sheets, etc., having high optical value, high hardness, and high bending strength at low cost.

VI, optical instrument E

The tempered glass of the present invention and the optical element D formed therefrom can be used for various optical instruments E, and by forming an optical component or an optical assembly using one or more optical elements D, can be used for, for example, imaging devices, sensors, microscopes, medical technologies, digital projection, communications, optical communication technologies/information transmission, optics/lighting in the automotive field, lithography technologies, steppers, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices including such circuits and chips, and are particularly suitable for application to image pickup devices and apparatuses in the vehicle-mounted field because of their high hardness, excellent bending strength and chemical stability.

Examples

The present invention is explained by the following examples, but the present invention should not be limited to these examples.

The melting and shaping methods for producing the glass composition may employ techniques well known to those skilled in the art. The preparation method comprises the steps of weighing and mixing glass raw materials (carbonate, nitrate, sulfate, hydroxide, oxide, boric acid and the like) according to the proportion of glass oxide, putting the glass raw materials into a smelting device (such as a platinum crucible), then carrying out appropriate stirring, clarification and homogenization at 1250-1350 ℃, cooling to below 1200 ℃, pouring or leaking and injecting the glass raw materials into a forming die, and finally carrying out post-treatment such as annealing, processing and the like or directly carrying out compression forming by a precise compression technology.

[ glass composition examples ]

The glass compositions in the examples of the present invention were formed by the above-described methods and then tested according to the above-described property test methods, and the results of the measurements are shown in tables 1 to 3.

The sample glass is cut into a size of 20X 10mm, put into a muffle furnace with the temperature of 700 ℃ and 900 ℃ for 30 minutes, taken out and put into heat preservation cotton for slow cooling, the surface is polished after cooling, and the surface crystallization condition is observed under a microscope and is represented by K. No obvious crystallization is marked as "A", and obvious crystallization is marked as "B".

TABLE 1

TABLE 2

TABLE 3

[ optical preform A example ]

The glasses obtained in examples 1 to 30 in tables 1 to 3 were cut into a predetermined size, and then a release agent was uniformly applied to the surface of the glass, followed by heating, softening, and press molding to prepare preforms of various lenses and prisms 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.

[ optical element B example ]

The preforms obtained from the above optical preform examples were annealed to reduce the deformation in the glass and to fine-tune the optical properties such as refractive index to the 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 optical element may be coated with an antireflection film.

[ optical instrument C example ]

The above-described optical element B can be used, for example, for imaging devices, sensors, microscopes, medical technologies, digital projection, communications, optical communication technologies/information transmission, optics/lighting in the automotive field, photolithography, steppers, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices including such circuits and chips, by optically designing, by forming an optical component or optical assembly using one or more optical elements B.

[ chemically tempered glass example ]

The glass compositions obtained in Table 3 above were cut or pressed into shapes suitable for the determination of bending strength and hardness, placed on an anti-corrosion sample holder, and subjected to KNO₃And/or NaNO₃Ion exchange treatment is carried out for 4-8h at 480 ℃ of 370-one in salt bath to obtain the chemical toughened glass shown in the table 4, and the bending strength and hardness performance of the obtained chemical toughened glass are tested to obtain the resultsAs shown in the table, since the chemically tempered glass of the present invention is made of the above glass composition, it has the same properties of refractive index, Abbe number, chemical stability, transition temperature and devitrification resistance as those of the above glass composition.

TABLE 4

[ optical element D example ]

The glass compositions described in tables 1 to 3 were cut or pressed into a predetermined shape, annealed and fine-tuned, and then chemically tempered to form chemically tempered glass, or an antireflection film was coated on the surface to form an optical element D.

[ optical instrument E example ]

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

Claims

1. Glass composition characterized in that it comprises, in percentages by weight: SiO2₂：20-40%；ZrO₂：1-12%；TiO₂：10-28%；Nb₂O₅：2-15%；Na₂O：11.45-25%；La₂O₃：3-20%；MgO：0-8.64%，（Nb₂O₅+TiO₂)/ La₂O₃Is 1.67-6.

2. The glass composition of claim 1, further comprising: ZnO: 0 to 10 percent; al (Al)₂O₃：0-10%；Li₂O：0-10%；K₂O：0-5%；CaO：0-10%；SrO：0-10%；BaO：0-10%；B₂O₃：0-15%；WO₃：0-10%；Gd₂O₃：0-10%；Y₂O₃：0-10%；Yb₂O₃：0-10%；Sb₂O₃：0-1%。

3. Glass composition characterized in that it consists, expressed in weight percentages, of: SiO2₂：20-40%；ZrO₂：1-12%；TiO₂：10-28%；Nb₂O₅：2-15%；Na₂O：11.45-25%；La₂O₃：3-20%；ZnO：0-10%；Al₂O₃：0-10%；Li₂O：0-10%；K₂O：0-5%；MgO：0-8.64%；CaO：0-10%；SrO：0-10%；BaO：0-10%；B₂O₃：0-15%；WO₃：0-10%；Gd₂O₃：0-10%；Y₂O₃：0-10%；Yb₂O₃：0-10%；Sb₂O₃：0-1%，（Nb₂O₅+TiO₂)/ La₂O₃Is 1.67-6.

4. The glass composition of any one of claims 1-3, wherein the SiO is₂: 23 to 38 percent; and/or ZrO₂: 3 to 11 percent; and/or La₂O₃: 5 to 18 percent; and/or ZnO: 0 to 8 percent; and/or TiO₂: 12 to 25 percent; and/or Nb₂O₅: 4 to 12 percent; and/or Na₂O: 11.45 to 20 percent; and/or Al₂O₃: 0 to 5 percent; and/or Li₂O: 0 to 5 percent; and/or WO₃: 0 to 5 percent; and/or MgO: 0 to 5 percent; and/or CaO: 0 to 5 percent; and/or SrO: 0 to 5 percent; and/or BaO: 0 to 5 percent; and/or B₂O₃: 0 to 10 percent; and/or Gd₂O₃: 0 to 5 percent; and/or Y₂O₃: 0 to 5 percent; and/or Yb₂O₃: 0 to 5 percent; and/or Sb₂O₃：0-0.5%。

5. The glass composition according to any one of claims 1 to 3, wherein the glass composition is characterized byIn the middle, BaO + SrO + CaO + MgO is 0-12%; and/or BaO + SrO is 0-10%; and/or Li₂O+Na₂O+K₂The content of O is 11.45-27%.

6. The glass composition according to claim 1, wherein Li is Li₂O/（Li₂O+Na₂O+K₂O) is 0.6 or less.

7. The glass composition according to any one of claims 2 to 3, wherein Li₂O/（Li₂O+Na₂O+K₂O) is 0.42 or less.

8. The glass composition of any one of claims 1-3, wherein (Nb) is₂O₅+TiO₂)/ La₂O₃1.67-5.5; and/or Li₂O+Na₂O+K₂The content of O is 11.45-25%.

9. The glass composition according to claim 1, wherein Li is Li₂O/（Li₂O+Na₂O+K₂O) is 0.5 or less.

10. The glass composition of any one of claims 1-3, wherein the SiO is₂: 25 to 35 percent; and/or TiO₂: 15 to 23 percent; and/or B₂O₃: 0 to 5 percent; and/or (Nb)₂O₅+TiO₂)/ La₂O₃Is 2 to 5; and/or Li₂O/（Li₂O+Na₂O+K₂O) is 0.4 or less.

11. The glass composition of any one of claims 1-3, which does not contain Gd₂O₃And/or Yb₂O₃。

12. As in any one of claims 1 to 3The glass composition is characterized in that the refractive index nd of the glass is 1.68-1.77; abbe number v_dIs 25-34.

13. The glass composition according to any of claims 1 to 3, wherein the glass has a refractive index nd in the range of from 1.69 to 1.76; abbe number v_dIs 26-33.

14. The glass composition of any one of claims 1-3, wherein the glass has a glass transition temperature Tg of 600 ℃ or less and an acid resistance stability D_AIs more than 2 types, and has water-resistant stability D_WIs more than 2 types.

15. The glass composition of any one of claims 1-3, wherein the glass has an acid resistance stability D_AIs class 1, stability against water action D_WIs type 1.

16. An optical preform made from the glass composition of any of claims 1-15.

17. An optical element made using the glass composition of any one of claims 1-15.

18. An optical device made using the glass composition of any one of claims 1-15.

19. Chemically tempered glass produced by chemical tempering using a glass composition as claimed in any of claims 1 to 15.

20. The chemically tempered glass of claim 19, wherein the bending strength σ is 550MPa or more and the Knoop hardness H is_k≥540×10⁷Pa; the impact strength is that 32g of steel ball can not be broken when falling from the height of 300mm to the toughened glass.

21. The chemically tempered glass of claim 19, wherein the impact strength is such that 32g of steel balls do not break when dropped from a height of 500mm or more to the tempered glass.

22. The chemically tempered glass of claim 19, wherein the impact strength is such that 32g of steel balls do not break when dropped from a height of 600mm or more to the tempered glass.

23. The chemically tempered glass of claim 19, wherein the impact strength is such that 32g of the steel ball will not break when dropped from a height of 700mm or more toward the tempered glass.

24. An optical element made of the chemically tempered glass as claimed in claim 19.

25. An optical instrument made of the chemically tempered glass as claimed in claim 19.