CN111051262A

CN111051262A - Glass

Info

Publication number: CN111051262A
Application number: CN201880055878.1A
Authority: CN
Inventors: 坂上贵寻
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2017-08-31
Filing date: 2018-08-20
Publication date: 2020-04-21
Anticipated expiration: 2038-08-20
Also published as: CN111051262B; JPWO2019044563A1; JP7092135B2; WO2019044563A1

Abstract

The invention provides a glass with small mechanical strength deviation. A glass comprising a chemically strengthened layer constituting at least a part of a surface layer thereof, wherein P, Al and an alkali metal composed of either or both of Li and Na are contained in the glass except for the chemically strengthened layer.

Description

Glass

Technical Field

The present invention relates to a glass in which variation in mechanical strength is suppressed.

Background

Near-infrared cut filter glass using phosphate glass or fluorophosphate glass has been used in a solid-state imaging Device module using a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like, which is used for a digital camera or the like. In recent years, there has been a demand for downsizing of solid-state imaging element modules and digital cameras mounted in mobile terminals such as mobile phones and smartphones, and therefore filter glasses having an extremely thin plate thickness have been required.

When the filter glass is made thin, for example, the bending strength of the glass may be reduced.

In the past, a method of chamfering an end face of a glass has been proposed from the viewpoint of improving the bending strength of the glass (for example, see patent document 1). Since a scratch on the glass surface becomes a starting point of a crack when a bending stress is applied to the glass, this method is a method of improving the strength of the glass by removing the scratch. Further, a method of treating a crack in an end face of a glass plate to a predetermined length or less by etching has been proposed (for example, see patent document 2). Further, a method of cutting glass using an internal modification type laser has been proposed (for example, see patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2000-169166

Patent document 2: japanese laid-open patent publication No. 2010-168262

Patent document 3: international publication No. 2013/027645

Disclosure of Invention

In each of the above patent documents, on the premise that the end portion of the glass becomes a starting point of breakage when bending stress is generated in the glass, an operation of removing or reducing a minute notch, a crack, or a scratch in the end portion is particularly performed.

However, when trying to examine in detail the state of stress acting on glass when the device is used, for example, when a strong impact is applied to the device in a short time, it is conceivable that the glass mounted in the device is bent greatly in an unfixed plane (central portion of the glass) as compared with the end portion fixed to a housing or the like with an adhesive. Therefore, it is important to consider the in-plane strength of the glass.

The in-plane strength of the glass can be measured by the breaking load. Here, it is considered that the breaking load of the glass needs to be high in average value, but it is also important to make the variation of the breaking load small. That is, when the variation in breaking load is large, although the ratio is very small, there is a possibility that glass having a low breaking load is mixed, and there is a risk that the glass is cracked when the apparatus is used. On the other hand, when the variation in breaking load of glass is small, the minimum value of breaking load can be estimated to some extent, and therefore, it is possible to avoid using glass with excessively low breaking load for equipment.

The present invention has been made under such a background, and an object thereof is to provide a glass having a small variation in mechanical strength.

The glass of the present invention is characterized in that at least a part of a surface layer is composed of a chemically strengthened layer, and P, Al and an alkali metal composed of either or both of Li and Na are contained in the glass except for the chemically strengthened layer.

According to the present invention, a glass having small variations in mechanical strength can be provided.

Drawings

FIG. 1 is a sectional view showing one embodiment of the glass of the present invention.

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described. The present invention is not limited to these embodiments, and modifications and variations can be made to these embodiments without departing from the spirit and scope of the present invention.

FIG. 1 is a sectional view showing one embodiment of the glass of the present invention. The surface layer of the glass 10 including the main surfaces on both sides thereof is composed of a chemically strengthened layer 2, and the portion other than the chemically strengthened layer 2 is a glass interior 1. The structure of the chemically strengthened layer of the glass of the present invention is not limited to this. In the glass of the present invention, at least a part of the surface layer may be formed of a chemically strengthened layer.

The glass interior 1 of the glass 10 contains, as essential components, respective components of P (phosphorus), Al (aluminum), and an alkali metal (of which, one or both of Li (lithium) and Na (sodium)) are contained. Hereinafter, the alkali metal composed of either or both of Li and Na contained in the glass interior 1 is represented by "R" as necessary.

The glass 10 is constituted, for example, as follows: the surface layer including the main surfaces on both sides of the precursor having the same size as the glass 10 and the same composition as the glass interior 1 of the glass 10 as a whole is converted into the chemically strengthened layer 2 by ion exchange, and the portion holding the composition of the precursor not ion-exchanged exists as the glass interior 1 on the inner side of the surface layer. That is, in the glass of the present invention, the chemically strengthened layer and the inside of the glass are both made of glass, but the glass compositions of the two are different. Hereinafter, the precursor of the glass before ion exchange, which has the same composition as the composition of the inside of the glass as a whole, is simply referred to as "glass precursor".

The ion exchange means that the R component in the glass precursor is ion-exchanged with other alkali metal ions having a valence of 1 and an ionic radius larger than that of the R component. For example, Li in the glass precursor⁺(ionic radius: 60pm) was ion-exchanged to Na⁺(ionic radius: 95pm), Na in glass precursor⁺Is ion exchanged into K⁺(ionic radius: 133pm), and the like. With Li in the glass precursor⁺Na ion-exchanged and diffused to the glass⁺Can be ion exchanged to K⁺。

Therefore, the chemically strengthened layer contains Na in comparison with the glass composition in the glass⁺And K⁺A glass composition containing a large amount of either one or both of them. In the glass of the present invention, the composition of the glass interior and the chemically strengthened layer other than alkali metal is not different. In the following description, the components common to the interior of the glass and the chemically strengthened layer are described as the components of the glass of the present invention.

The glass of the present invention contains P and Al. In the glass of the present invention, P is a network-forming component and is a main component necessary for vitrification. In the glass of the present invention, Al is a modifying component of the glass and is a component for suppressing crystallization and phase separation during glass production. The glass of the present invention contains R in the glass. That is, in the present invention, the glass precursor whose surface layer is ion-exchanged to become the glass of the present invention contains R due to the ion-exchange, and the glass of the present invention obtained contains R inside the glass.

The present inventors have conducted extensive studies and, as a result, found that: when the chemically strengthened layer 2 is present on at least a part of the surface layer of the glass 10, variation in mechanical strength of the glass 10 is reduced. The reason for this is considered to be due to the following mechanism.

An important factor for the deviation of the mechanical strength of the glass is the scratch existing on the surface of the glass. When tensile stress acts on glass having a scratch on the surface, stress concentration occurs at the tip of the scratch, causing breakage. Since scratches on the glass surface are caused by various external factors such as production processes and treatments during use, the depths of the scratches are not the same. Particularly, stress concentration is likely to occur in a deep scratch, and even a weak tensile stress causes breakage of the glass, thereby causing variation in the mechanical strength of the glass.

In contrast, in the glass of the present invention, ions having a larger ion radius than the original R component are diffused sufficiently deeply into the surface layer of the glass precursor instead of the original R component, thereby forming a chemically strengthened layer in the surface layer, and the glass structure in the vicinity of the end of a deep flaw expands, whereby the stress generated at the end of the flaw when a tensile stress acts on the glass can be reduced. As a result, it is considered that the glass of the present invention does not have a reduced mechanical strength even when a deep scratch is present, and the variation in mechanical strength is small.

In the glass 10 of the present invention, the chemical strengthening layer 2 may be provided on the entire surface layer of the glass 10, or may be provided only on a part of the surface layer. As shown in fig. 1, when the glass 10 is plate-shaped, a chemical strengthening layer 2 is preferably provided on a surface layer including a main surface. This is because when bending stress acts on the plate-shaped glass, the amount of deformation of the main surface is large.

Chemical strengthening layer 2 is preferably spaced from the glass10 has a surface thickness of 1 to 100 μm in the depth direction. This is due to: when the thickness of the chemical strengthening layer 2 is less than 1 μm, the effect of reducing the variation in the mechanical strength of the glass 10 cannot be sufficiently obtained. When the thickness of the chemically strengthened layer 2 exceeds 100 μm, the process for forming the chemically strengthened layer 2 requires a long time. The thickness of the chemically strengthened layer 2 is more preferably 2 to 50 μm, and still more preferably 3 to 30 μm, from the viewpoint of suppressing breakage due to tensile stress generated in the glass. The chemically strengthened layer 2 of the glass 10 may be formed using an electron probe Micro Analyzer (electron probe Micro Analyzer) as Na⁺And K⁺Either or both of them are contained in a larger amount than the glass interior 1.

The chemically strengthened layer 2 may have a compressive stress. If the chemically strengthened layer 2 having a compressive stress is present on the surface of the glass 10, the extension of the crack present on the surface of the glass 10 is suppressed when a bending stress is applied to the glass 10, and the glass 10 having a high mechanical strength can be obtained. Further, as described above, since the surface layer of the glass 10 can have the chemical strengthening layer 2, the variation in the mechanical strength of the glass 10 can be reduced, and therefore, compared with a glass having the same composition without the chemical strengthening layer 2, that is, a glass precursor, a glass having a high average breaking load and a small variation in the breaking load can be obtained. Since the probability of existence of glass having an excessively low breaking load is very small, the risk of breakage of the glass 10 when the glass 10 is used in a machine can be reduced.

The compressive stress of the chemically strengthened layer 2 of the glass 10 is preferably 10 to 1000 MPa. The compressive stress of the chemically strengthened layer 2 can be measured using a birefringence measuring device.

When the glass 10 is cut into small pieces so as to match the product size, for example, it is preferable to cut with an internal modification type laser. Generally, when glass is cut with an internal modification type laser beam, a modification region is formed inside the glass by condensing the laser beam, and the glass is cut by extending a crack from the modification region. In the glass small piece obtained by cutting, if the modified region reaches an end portion of the glass small piece (an intersection line of a main surface and an end surface of the glass small piece), when an external stress is generated in the glass small piece, the glass small piece is broken with the end portion as a starting point, and thus the glass small piece has low mechanical strength. As the external stress, stretching is preferable from the viewpoint of accuracy of a cut surface such as bending stress and tape expansion (テープエキスパンド).

In the glass 10, since the chemical strengthening layer 2 having a compressive stress is present in the surface layer, a tensile stress is present in the glass interior 1 forming the modified region. Thus, when the glass 10 is cut by using the internal modification type laser, the power of the laser beam required for forming the modified region can be suppressed, and the modified region can be reduced. Therefore, the reformed region does not exist at the end of the cut small glass piece, and as a result, a small glass piece having high mechanical strength can be obtained.

The glass of the present invention preferably has a glass transition temperature (Tg) of 600 ℃ or lower. In the glass of the present invention, the Tg of the chemically strengthened layer is substantially equal to the Tg inside the glass, and is treated as the same value. That is, the Tg of the glass precursor and the Tg of the glass of the present invention obtained from the glass precursor can be treated as the same value.

When Tg is 600 ℃ or lower, the glass 10 having the chemically strengthened layer 2 can be produced from the glass precursor in a short time in the surface layer. Further, since the chemically strengthened layer 2 can be formed at a relatively low temperature, the surface roughness of the chemically strengthened layer 2 can be suppressed, and it is preferable to use the glass 10 as an optical element. Further, if the chemically strengthened layer 2 can be formed at a low temperature in a short time, the effect of suppressing the manufacturing cost (electric energy) of the glass 10 can be obtained. The Tg of the glass 10 is preferably 580 ℃ or lower, more preferably 570 ℃ or lower.

On the other hand, if Tg is too low, relaxation of compressive stress is likely to occur in the glass 10 having the chemically strengthened layer 2, and therefore it is preferable to be 300 ℃. That is, the Tg of the glass 10 is preferably 300 to 570 ℃. The Tg can be measured, for example, by a thermal expansion method.

The glass 10 is preferably a phosphate glass. The phosphoric acid-based glass is a glass containing P as a main network-forming component, and in the present invention, the glass is a concept including phosphate glass, fluorophosphate glass containing fluorine, silicophosphate glass containing silicon, and sulfur phosphate glass containing sulfur.

Specifically, the phosphate glass of the present invention preferably contains 35 to 80% by mass of P in terms of oxide in the glass interior 1₂O₅Or 20 to 60% of P in cation%⁵⁺。

The glass 10 preferably contains F (fluorine) as a glass component. It is known that glass containing P as a network-forming component is poor in weatherability (particularly, water resistance). The glass 10 can be greatly improved in weathering resistance by containing F as a glass component.

The glass 10 preferably contains Cu (copper) as a glass component. Cu is known as a component that absorbs near infrared rays, for example, light having a wavelength of 700 to 1100 nm. The glass 10 can be used as an optical filter glass having excellent near-infrared absorption characteristics by containing Cu.

The glass 10 is, for example, glass of 2 embodiments having 2 compositions shown below, respectively, inside the glass.

The glass of embodiment 1 is a so-called copper-containing phosphate glass, and particularly contains a P component and a Cu component (Cu) in the glass²⁺) The infrared ray cut-off device has a function of absorbing light having a wavelength in the near infrared region and greatly cutting off infrared rays.

The glass of embodiment 1 preferably contains P in the glass in mass% in terms of oxide as described below₂O₅：35～80％、Al₂O₃：5～20％、ΣR₂O: 3 to 30% (wherein, R)₂O is Li₂O and Na₂More than one of O, Sigma R₂O represents their total amount), Σ R' O: 3 to 35% (where R 'O is at least one of MgO, CaO, SrO, BaO and ZnO, and Σ R' O represents the total amount thereof), CuO: 0.5 to 20 percent.

The reason why the contents of the respective components constituting the glass in the glass of embodiment 1 are limited as described above will be described below. In the following description, the content of each component is expressed by mass% in terms of oxide in the glass.

P₂O₅For forming glass compositionsThe component (glass-forming oxide) is an essential component for improving the near infrared ray cut-off property. P₂O₅When the content of (b) is less than 35%, the effect cannot be sufficiently obtained, and when it exceeds 80%, the melting temperature rises and the transmittance in the visible region is lowered, which is not preferable. P₂O₅The content of (b) is preferably 38 to 77%, more preferably 40 to 75%.

Al₂O₃Is an essential component for improving durability. Al (Al)₂O₃When the content of (B) is less than 5%, the effect cannot be sufficiently obtained, and when it exceeds 20%. The glass is not preferable because the melting temperature is high and the near infrared ray cut-off property and the visible region transmittance are lowered. Al (Al)₂O₃The content of (b) is preferably 5.5 to 17%, more preferably 6 to 15%.

R₂O is an essential component for forming a chemically strengthened layer for lowering the melting temperature of glass. R₂O is Li contained in the glass₂O and Na₂O or more. Sigma R₂O means Li₂O and Na₂The total amount of O, i.e. Li₂O+Na₂O。ΣR₂When O is less than 3%, the effect is not sufficient, and when it exceeds 30%, the glass becomes unstable, which is not preferable. Sigma R₂O is preferably 5 to 28%, more preferably 6 to 25%.

Li₂O has the effect of forming a chemically strengthened layer and lowering the melting temperature of the glass. Li₂When the content of O exceeds 15%, the glass becomes unstable, which is not preferable. Li₂The content of O is preferably 0 to 10%, more preferably 0 to 8%.

Na₂O has the effect of forming a chemically strengthened layer and lowering the melting temperature of the glass. Na (Na)₂When the content of O exceeds 25%, the glass becomes unstable, which is not preferable. Na (Na)₂The content of O is preferably 0 to 22%, more preferably 0 to 20%.

The glass may contain K inside₂O as a radical scavenger of R₂An alkali metal oxide other than O. K₂O has the effect of promoting the formation of a chemically strengthened layer and lowering the melting temperature of the glass. K₂Content of OPreferably 0 to 25%. K₂When the content of O exceeds 25%, the glass becomes unstable, which is not preferable. K₂The content of O is preferably 0 to 20%, more preferably 0 to 15%.

R' O is an essential component for improving the stability of the glass and lowering the melting temperature of the glass. R' O is at least one of MgO, CaO, SrO, BaO and ZnO contained in the glass. Σ R' O is the total amount of MgO, CaO, SrO, BaO, and ZnO, that is, MgO + CaO + SrO + BaO + ZnO. When Σ R' O is less than 3%, the effect is insufficient, and when it exceeds 35%, the glass becomes unstable, which is not preferable. Preferably, the Sigma R' O is 3.5 to 32%, and more preferably 4 to 30%.

Although not an essential component, MgO has the effect of improving the stability of the glass. When the content of MgO exceeds 5%, the near infrared ray cut-off property is undesirably lowered. The content of MgO is preferably 3% or less, more preferably 2% or less.

Although CaO is not an essential component, CaO has an effect of improving the stability of the glass. When the content of CaO exceeds 10%, the near infrared ray cut-off property is lowered, which is not preferable. The content of CaO is preferably 7% or less, more preferably 5% or less.

SrO is not an essential component, but has the effect of improving the stability of the glass. When the SrO content exceeds 15%, the near infrared ray cut-off property is not preferable. The content of SrO is preferably 0 to 12%, more preferably 0 to 10%.

BaO is not an essential component, but has an effect of lowering the melting temperature of the glass. When the content of BaO exceeds 30%, the glass becomes unstable, which is not preferable. The content of BaO is preferably 0 to 27%, more preferably 0 to 25%.

Although ZnO is not an essential component, ZnO has the effect of lowering the melting temperature of the glass. When the content of ZnO exceeds 10%, the solubility of the glass is not preferable because it is poor. The content of ZnO is preferably 8% or less, more preferably 5% or less.

CuO is a component for improving the near infrared ray cut-off property. When the content of CuO is less than 0.5%, the effect cannot be sufficiently obtained, and when it exceeds 20%, the transmittance in the visible region is lowered, which is not preferable. The content of CuO is preferably 0.8 to 19%, more preferably 1.0 to 18%.

The glass of embodiment 2 is a so-called copper-containing fluorophosphate glass, and is composed of, in particular, a P component and a Cu component (Cu) in the glass²⁺) Has a function of absorbing light having a wavelength in the near infrared region to cut off infrared rays significantly, and is excellent in weather resistance.

The glass of embodiment 2 preferably contains P in cationic% in the glass interior⁵⁺：20～60％、Al³⁺：3～20％、ΣR⁺: 5 to 40% (wherein, R)⁺Is Li⁺And Na⁺More than one of, Sigma R⁺Represents the total amount thereof), Sigma R'²⁺: 5-30% (wherein, R'²⁺Is Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺And Zn²⁺Of (a) or more, Sigma R'²⁺Representing the total amount thereof), Cu²⁺And Cu⁺The total amount of (A): 0.5 to 25%, and contains F in terms of anion%^－：10～70％。

The reason why the content (expressed as cation% and anion%) of each component constituting the glass in the glass of embodiment 2 is defined as described above will be described below.

In the present specification, "cation%", "anion%" means the following units. First, the constituent components in the composition of the glass are divided into a cationic component and an anionic component. The "cation%" means a unit in which the content of each cation component is expressed by percentage, assuming that the total content of all cation components contained in the glass is 100 mol%. "anion%" means a unit in which the content of each anion component is expressed by percentage, assuming that the total content of all anion components contained in the glass is 100 mol%.

In the following description, unless otherwise specified, the values of the respective contents and the total content of the cationic components are values represented by% of cations in the glass, and the values of the respective contents and the total content of the anionic components are values represented by% of anions in the glass.

P⁵⁺For forming glassThe main component is an essential component for improving the cut-off property in the near infrared region. P⁵⁺When the content of (b) is less than 20%, the effect cannot be sufficiently obtained, and when the content exceeds 60%, the glass becomes unstable, which causes problems such as deterioration of weather resistance. P⁵⁺The content of (b) is more preferably 20 to 58%, still more preferably 22 to 56%, still more preferably 24 to 54%, and particularly preferably 25 to 50%.

Al³⁺Is an essential component for improving weather resistance and the like. Al (Al)³⁺When the content of (b) is less than 3%, the effect cannot be sufficiently obtained, and when the content exceeds 20%, the glass becomes unstable, which causes problems such as reduction in infrared ray cut-off property, and the like, and is not preferable. Al (Al)³⁺The content of (b) is more preferably 4 to 18%, still more preferably 4.5 to 15%, still more preferably 5 to 13%. In addition, Al is used₂O₃、Al(OH)₃As Al³⁺The raw material (2) is subjected to increase in dissolution temperature, generation of an unmelted product, and F^－The amount of AlF is not preferable because the glass becomes unstable due to a decrease in the amount of the raw material, and AlF is preferable₃。

R⁺Is an essential component for forming a chemically strengthened layer, lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, and the like. R⁺Means Li contained in the glass⁺And Na⁺Any one or more of the above. In addition, Σ R⁺Refers to Li⁺With Na⁺In total, i.e. represents Li⁺+Na⁺。ΣR⁺When the content is less than 5%, the effect cannot be sufficiently obtained, and when the content exceeds 40%, the glass is unstable, which is not preferable. Sigma R⁺More preferably 6 to 38%, still more preferably 10 to 37%, and still more preferably 15 to 36%.

Li⁺The glass is a component for forming a chemically strengthened layer, lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, and the like. As Li⁺The content of (c) is preferably 5 to 40%. When the content is less than 5%, the effect cannot be sufficiently obtained, and when the content exceeds 40%, the glass is unstable, which is not preferable. Li⁺The content of (b) is more preferably 8 to 38%, still more preferably 10 to 35%, still more preferablyThe step is preferably 6-30%.

Na⁺Is a component for forming a chemically strengthened layer, lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, and the like. As Na⁺The content of (c) is preferably 5 to 40%. When the content is less than 5%, the effect cannot be sufficiently obtained, and when the content exceeds 40%, the glass is unstable, which is not preferable. Na (Na)⁺The content of (b) is more preferably 5 to 35%, and still more preferably 6 to 30%.

K⁺The component has the effects of promoting the formation of a chemically strengthened layer, lowering the melting temperature of glass, lowering the liquidus temperature of glass, and the like. As K⁺The content of (c) is preferably 0.1 to 30%. Containing K⁺In the case of (3), the effect cannot be sufficiently obtained when the content is less than 0.1%, and the glass becomes unstable when the content exceeds 30%, which is not preferable. K⁺The content of (b) is more preferably 0.5 to 25%, and still more preferably 0.5 to 20%.

R’²⁺The glass is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, improving the strength of glass, and the like. R'²⁺Mg contained in the glass²⁺、Ca²⁺、Sr²⁺、Ba²⁺And Zn²⁺Any one or more of the above. Additionally, (# R)'²⁺Refers to Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺、Zn²⁺In total amount of (i) represents Mg²⁺+Ca²⁺+Sr²⁺+Ba²⁺+Zn²⁺。ΣR’²⁺When the content is less than 5%, the effect cannot be sufficiently obtained, and when the content exceeds 30%, problems such as instability of the glass, reduction in infrared ray cut-off property, and reduction in strength of the glass occur, which is not preferable. Sigma R'²⁺More preferably 5 to 28%, still more preferably 7 to 25%, and still more preferably 9 to 23%.

Mg²⁺Although not essential, the glass is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, improving the strength of the glass, and the like. As Mg²⁺The content of (c) is preferably 1 to 30%. Containing Mg²⁺In the case of (2), when the content is less than 1%, the content cannot be sufficiently obtainedIf the effect exceeds 30%, the glass becomes unstable, which is not preferable. Mg (magnesium)²⁺The content of (b) is more preferably 1 to 25%, and still more preferably 1 to 20%.

Ca²⁺Although not essential, the glass is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, improving the strength of the glass, and the like. As Ca²⁺The content of (c) is preferably 1 to 30%. Containing Ca²⁺In the case of (3), the effect cannot be sufficiently obtained when the content is less than 1%, and the glass becomes unstable when the content exceeds 30%, which is not preferable. Ca²⁺The content of (b) is more preferably 1 to 25%, and still more preferably 1 to 20%.

Sr²⁺The component is not essential, but is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, or the like. As Sr²⁺The content of (c) is preferably 1 to 30%. Containing Sr²⁺In the case of (3), the effect cannot be sufficiently obtained when the content is less than 1%, and the glass becomes unstable when the content exceeds 30%, which is not preferable. More preferably 1 to 25%, and still more preferably 1 to 20%.

Ba²⁺The component is not essential, but is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, or the like. As Ba²⁺The content of (c) is preferably 1 to 30%. Containing Ba²⁺In the case of (3), the effect cannot be sufficiently obtained when the content is less than 1%, and the glass becomes unstable when the content exceeds 30%, which is not preferable. Ba²⁺The content of (b) is more preferably 1 to 25%, and still more preferably 1 to 20%.

Zn²⁺Although not an essential component, it has the effect of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. As Zn²⁺The content of (c) is preferably 1 to 30%. Containing Zn²⁺In the case of (3), the effect cannot be sufficiently obtained when the content is less than 1%, and the solubility of the glass is undesirably deteriorated when the content exceeds 30%. Zn²⁺The content of (b) is more preferably 1 to 25%, and still more preferably 1 to 20%.

Cu²⁺And Cu⁺The total content of (a) is an essential component for cutting down to near infrared rays.If Cu²⁺And Cu⁺If the total content of (2) is less than 0.5%, the effect cannot be sufficiently obtained when the thickness of the glass is made thin, and if it exceeds 25%, the transmittance in the visible region is lowered, which is not preferable. Cu²⁺And Cu⁺The total content of (a) is more preferably 0.2 to 24%, still more preferably 0.3 to 23%, and still more preferably 0.4 to 22%.

Sb³⁺Although not essential, the glass has the effect of increasing Cu content by improving the oxidizing property of the glass²⁺The concentration of the ions improves the near infrared ray cut-off performance. Containing Sb³⁺In this case, the content is preferably 1% or less. Sb³⁺When the content of (3) is more than 1%, the stability of the glass is lowered, which is not preferable. Sb³⁺The content of (b) is preferably 0.01 to 8%, more preferably 0.05 to 0.5%, and further preferably 0.1 to 0.3%.

O^2－The glass is a component for stabilizing glass and improving mechanical properties such as strength, hardness, and elastic modulus. O is^2－The content of (C) is preferably 30 to 90%. O is^2－When the content of (b) is less than 30%, the effect cannot be sufficiently obtained, and when the content exceeds 90%, the glass becomes unstable and the weather resistance is lowered, which is not preferable. O is^2－The content of (b) is more preferably 30 to 80%, and still more preferably 30 to 75%.

F^－Is a component for stabilizing glass and improving weather resistance. F^－When the content of (b) is less than 10%, the effect cannot be sufficiently obtained, and when it exceeds 70%, mechanical properties such as strength, hardness and elastic modulus may be deteriorated, which is not preferable. F^－The content of (b) is more preferably 10 to 50%, and still more preferably 15 to 40%.

The glass of embodiment 1 preferably does not substantially contain PbO or As₂O₃、V₂O₅、LaY₃、YF₃、YbF₃、GdF₃. PbO is a component for lowering the viscosity of the glass and improving the workability of production. In addition, As₂O₃Is a component that functions as an excellent clarifying agent capable of generating a clarified gas in a wide temperature range. However, becausePbO and As₂O₃It is preferably not contained as much as possible because it is an environmentally-friendly substance.

V₂O₅Since absorption is present in the visible region, the transmittance of ultraviolet light may be reduced, and it is preferable to include the ultraviolet light as little as possible. LaY₃、YF₃、YbF₃、GdF₃In order to stabilize the glass, it is preferable to contain as little component as possible because the raw material is relatively expensive and the cost increases. Here, substantially not containing means intentionally not being used as a raw material, and unavoidable impurities mixed in from raw material components and a production process are considered not to be contained. The amount of such unavoidable impurities is, for example, 0.1% or less with respect to the entire glass interior.

In the glass of embodiment 2, a nitrate compound or a sulfate compound having cations forming the glass may be added as an oxidizing agent or a fining agent in the composition inside the glass. The oxidizing agent is Cu which converts Cu component in the glass⁺The effect of adjusting the/total Cu amount to a desired range. The amount of the nitrate compound and the sulfate compound added is preferably 0.5 to 10% by mass in terms of the ratio other than the total amount of the raw material mixture of the composition in the glass. When the amount is less than 0.5% by mass, the effect of improving transmittance is not obtained, and when it exceeds 10% by mass, glass formation becomes difficult. The amount of addition is more preferably 1 to 8 mass%, and still more preferably 3 to 6 mass%.

As the nitrate compound, there is Al (NO)₃)₃、LiNO₃、NaNO₃、KNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Sr(NO₃)₂、Ba(NO₃)₂、Zn(NO₃)₂、Cu(NO₃)₂And the like. As the sulfate compound, there is Al₂(SO₄)₃·16H₂O、Li₂SO₄、Na₂SO₄、K₂SO₄、MgSO₄、CaSO₄、SrSO₄、BaSO₄、ZnSO₄、CuSO₄And the like.

The glass of embodiment 2 has excellent weatherability because it contains F (fluorine) as an essential component. Specifically, the deterioration of the glass surface and the decrease in transmittance due to the reaction with moisture in the atmosphere can be suppressed. The weathering resistance can be evaluated by, for example, holding the optically polished glass sample in a high-temperature high-humidity chamber at 65 ℃ and 90% relative humidity for 1000 hours using a high-temperature high-humidity chamber. Then, the glass surface was visually observed for evaluation of the burned state. The transmittance of the glass before being charged into the high-temperature and high-humidity chamber may be compared with the transmittance of the glass after being held in the high-temperature and high-humidity chamber for 1000 hours.

The glass 10 may have any shape of plate, lens (concave, convex), tube, rod, and the like. For example, when the glass 10 is used as an optical filter, it is preferably plate-shaped.

When the glass 10 is used in a plate shape, the plate thickness is preferably 0.01 to 1 mm. If the thickness of the glass 10 is less than 0.01mm, the risk of breakage during production is high. In addition, if it exceeds 1mm, the mass of the glass 10 becomes large, which may prevent the weight reduction of the apparatus.

The glass 10 can be preferably used for the following applications utilizing the characteristic optical characteristics of phosphoric acid-based glass. Examples of the optical filter include low refractive glass, low dispersion glass, anomalous partial dispersion glass, athermal glass (a characteristic of small change in temperature due to polarizability), faraday rotation glass (paramagnetic glass), laser glass (a characteristic of large stimulated emission coefficient), and an optical filter (a characteristic of characteristic transmission and absorption in an ultraviolet region and an infrared region). The glass is particularly preferably used for 1 type of near infrared ray cut filter glass among optical filters.

The glass 10 may have an optical film such as an antireflection film, an infrared ray cut film, an ultraviolet ray cut film, or an infrared ray cut film on its surface. These optical thin films are formed of a single layer film or a multilayer film, and can be formed by a known method such as a vapor deposition method or a sputtering method. The glass 10 may have a resin layer on the surface thereof, in which a pigment or metal fine particles that absorb light of a specific wavelength are dispersed.

The method for producing the glass 10 is not particularly limited. Typically, the glass can be manufactured by forming a glass precursor having the same shape and size as those of the glass 10, and forming a chemically strengthened layer on the surface layer by ion exchange treatment.

Specifically, the raw materials are weighed and mixed so that the obtained glass precursor has a predetermined composition range, for example, the composition in the glass (mixing step). The raw material mixture was placed in a platinum crucible and heated and dissolved at a temperature of 700 to 1300 ℃ in an electric furnace (dissolution step). The mixture is sufficiently stirred, clarified, poured into a mold, and molded into a predetermined shape (molding step). Subsequently, the glass precursor is cut and polished to be processed into a predetermined shape (processing step). The glass precursor can be molded into a predetermined shape by an appropriate method such as press molding, hot press molding, danner molding, redraw molding, or verro molding.

The surface layer of the obtained glass precursor is ion-exchanged to form a chemically strengthened layer 2, thereby obtaining a glass 10 composed of the chemically strengthened layer 2 and a glass interior 1 which is not ion-exchanged (a chemically strengthened layer forming step). After the chemical strengthening layer forming step, the glass may be cut, polished, and immersed in a chemical solution (acidic or alkaline solution).

The chemical strengthening layer forming step is a step of performing ion exchange treatment on the surface layer of the glass precursor. The ion exchange treatment can be performed by, for example, immersing the glass precursor in a molten salt at 200 to 450 ℃ for about 1 to 50 hours. The temperature of the molten salt was defined as the ion exchange treatment temperature. The ion exchange treatment temperature is more preferably 215 to 400 ℃. The immersion time was taken as the ion exchange treatment time. The ion exchange treatment time is more preferably 2 to 30 hours.

The molten salt used depends on the composition of the alkali metal in the glass precursor. Ion exchange of glass precursor containing Li to Na⁺And/or K⁺In the molten salt of (1). Ion exchange of Na-containing glass precursor in K-containing⁺In the molten salt of (1). The molten salt may be, for example, sodium nitrate (NaNO)₃) The molten salt of (a) is,mixing potassium nitrate (KNO)₃) And sodium nitrate (NaNO)₃) Molten salt obtained by mixing them at an appropriate ratio.

The glass of the present invention has a chemically strengthened layer in the surface layer, and contains P, Al and an alkali metal composed of either or both of Li and Na in the glass, so that the glass has a small variation in mechanical strength. For example, in the plate-shaped glass of the present invention, when the in-plane strength of the glass is measured by the breaking load, the variation in the breaking load is small. Thus, since the minimum value of the breaking load is estimated to some extent, it is possible to avoid using glass with an excessively low breaking load for the equipment.

Examples

Table 1 shows examples of the present invention and comparative examples. Examples 1 to 4 are examples of the present invention, and example 5 is a comparative example of the present invention.

[ production of glass ]

In the production of the glasses of examples 1 to 5, first, glass precursors each composed of a glass material having the same composition were produced as follows. The composition of the glass material used was as follows, and Tg was 400 ℃.

The composition comprises the following components expressed by cation percent,

P⁵⁺：20～60％

Al³⁺：3～20％

ΣR⁺: 5 to 40% (wherein, R)⁺Is Li⁺、Na⁺More than one of, Sigma R⁺Indicating their combined amount)

ΣR’²⁺: 5-30% (wherein, R'²⁺Is Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺And Zn²⁺Of (a) or more, Sigma R'²⁺Indicating their combined amount)

Cu²⁺And Cu⁺The total amount of (A): 0.5 to 25 percent

Expressed as anion%, contains the following components.

F^－：10～70％

(preparation of glass precursor)

The glass material having the above composition is prepared by weighing and mixing the raw materials, placing the mixture in a platinum crucible having an internal volume of about 400cc, melting at 700 to 1300 ℃ for 2 hours, clarifying, stirring, pouring the mixture into a rectangular mold having a length of 50mm, a width of 50mm and a height of 20mm, which is preheated to about 300 to 500 ℃, and slowly cooling the mixture. Then, the obtained glass plate was polished to obtain a glass precursor having a length of 50mm, a width of 50mm and a thickness of 0.2 mm.

(Process for Forming chemically strengthened layer)

The glass precursors thus prepared were subjected to ion exchange treatment under the conditions (type and ratio (mass%) of molten salt, ion exchange treatment temperature, and ion exchange treatment time) shown in table 1, to form a chemically strengthened layer on the surface layer, thereby producing glasses of examples 1 to 4. In example 5, the glass precursor itself was not provided with a chemically strengthened layer.

(evaluation)

(1) Evaluation of Strength

The strength of each of the glasses of examples 1 to 5 and comparative examples obtained above was evaluated.

Strength evaluation the breaking load of the glass was measured using a ring-to-ring test. The detailed operation of the measurement method is as follows. Glass was placed on a backup ring (ring diameter: 30mm), and the load ring (ring diameter: 15mm) was pressed from above the glass at a load rate of 0.5 mm/min, and the breaking load was measured for the number of samples shown in Table 1. As a fracture tester, a TENSILON universal tester RTF-1310 manufactured by A & D was used. The obtained breaking loads (average value, maximum value, minimum value) are shown in table 1.

(2) Confirmation of compressive stress

The chemical strengthening layer of each glass of examples 1 to 5 and comparative example obtained above or the surface layer of example 5 was confirmed to have no compressive stress.

A birefringence measurement device (Abrio Micro Imaging System; manufactured by HINDS Instruments Inc.) was used to determine the presence or absence of compressive stress. As a confirmation method, a cross section of the glass in a direction perpendicular to the surface of the chemically strengthened layer was mirror-polished, and then the glass was observed from the direction of the polished surface by a birefringence measurement device. When the glass has a compressive stress, retardation due to birefringence is observed near the surface of the glass. In the absence of compressive stress, no retardation was observed. The measurement results are shown in table 1.

(3) Confirmation of ion exchange State

In examples 1 to 4, the ion exchange state of the surface layer of each glass of the examples on which the chemically strengthened layer was formed was measured using an electron probe micro-area analyzer (JXA 8230, manufactured by JEOL corporation). Specifically, Na in the glass is added⁺And K⁺A portion in which either or both of the contents are more than the inside of the glass is determined as a chemically strengthened layer, and the depth (thickness from the surface of the glass) and the ion exchange element (ion element diffused to the surface layer by ion exchange treatment in place of the alkali metal of the glass precursor) thereof are confirmed. The measurement results are shown in table 1. The depth of the chemically strengthened layer is the average of the number of samples.

[ Table 1]

From table 1, it can be seen that: the standard deviation of breaking load was smaller for each glass of the examples of the present invention than for the glass of the comparative example. Therefore, the risk of breakage can be reduced when used for equipment or the like. Therefore, when used for equipment or the like, the steel sheet can be used with a thinner sheet thickness with less risk of breakage.

Industrial applicability

The glass of the present invention is a glass in which at least a part of the surface layer is composed of a chemically strengthened layer, and the inside of the glass other than the chemically strengthened layer contains P, Al and an alkali metal composed of either or both of Li and Na, and therefore, the glass has little variation in mechanical strength.

Claims

1. A glass comprising a chemically strengthened layer constituting at least a part of a surface layer thereof, wherein P, Al and an alkali metal composed of either or both of Li and Na are contained in the glass except for the chemically strengthened layer.

2. The glass according to claim 1, wherein the thickness of the chemical strengthening layer is 1 to 100 μm.

3. The glass of claim 1 or 2, wherein the chemically strengthened layer has a compressive stress.

4. The glass according to any one of claims 1 to 3, wherein the glass has a glass transition temperature of 600 ℃ or lower.

5. The glass of any one of claims 1-4, wherein the network forming component of the glass is P.

6. The glass of any one of claims 1-5, wherein the glass comprises F.

7. The glass of any of claims 1-6, wherein the glass comprises Cu.

8. The glass according to any one of claims 1 to 7, wherein the glass contains, in terms of oxide-converted mass% inside: p₂O₅35～80％、Al₂O₃5～20％、ΣR₂O 3～30％、ΣR’O 3～35％、CuO 0.5～20％，

Wherein R is₂O is Li₂O、Na₂More than one of O, Sigma R₂O represents the total amount of the above-mentioned components,

r 'O is at least one of MgO, CaO, SrO, BaO and ZnO, and Σ R' O represents the total amount thereof.

9. The glass according to any one of claims 1 to 7, wherein the glass contains, in cation%: p⁵⁺20～60％、Al³⁺3～20％、ΣR⁺5～40％、ΣR’²⁺5～30％、Cu²⁺And Cu⁺0.5 to 25% in total, and contains F in terms of anion%^－10～70％，

Wherein R is⁺Is Li⁺、Na⁺More than one of, Sigma R⁺Which represents the total amount of them,

R’²⁺is Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺And Zn²⁺Of (a) or more, Sigma R'²⁺Indicating the total amount thereof.

10. The glass of any one of claims 1-9, wherein the glass is sheet-shaped.

11. The glass according to claim 10, wherein a thickness of the glass is 0.01mm to 1 mm.

12. The glass according to any one of claims 1 to 11, which is a near infrared ray cut filter glass.