TW201643127A - Glass ceramics and multi-layered inorganic membrane filter - Google Patents

Abstract

The invention provides glass ceramics with relatively high mechanical performance for a multi-layered inorganic membrane filter. The glass ceramics comprise the following ingredients by weight: 69-80% of SiO2, 8-12.5% of Li2O, 4-10% of Al2O3, 1.5-3% of P2O5, 1-8% of ZrO2, 0.5-3.0% of K2O, and 0.5-5% of MgO+ZnO+BaO+SrO. The glass ceramics do not contain PbO or As2O3 or other harmful ingredients, have relatively high expansion factor, can prevent refractive indexes of inorganic membranes from changing at the application temperature of the multi-layered inorganic membrane filter, can improve the product temperature stability, have relatively high mechanical performance and relatively good chemical stability, guarantee the durability of the filter, and have relatively high transmittance in the certain waveband (960-1600 nm).

Description

Glass-ceramic and multilayer inorganic membrane filters

The present invention relates to a glass ceramic and a multilayer inorganic film filter.

The multilayer film filter is composed of a substrate and an inorganic thin film formed on the substrate by a deposition deposition method, a radio frequency ion plating method, a magnetron sputtering method, or the like, and the inorganic thin film is alternately composed of a high refractive index inorganic film and a low refractive index inorganic film. . The multilayer filter has a specific wavelength cut off, a special wavelength or anti-reflection function, wherein the filter that cuts off a specific wavelength is a notch filter, and only a filter of a specific wavelength is a band pass filter, and the band pass The filter transmits a high-pass or low-pass filter (ND filter) through a specific short wavelength or long wavelength. Therefore, the multilayer film filter can be used as a passive component for performing splitting and combining of light waves, and is often used in an optical communication network.

In optical communication networks, a multi-layer membrane filter commonly used in WDM (wavelength-separated multiplexed) optical communication systems is called a band-pass filter (BPF), which is capable of separating multiple wavelengths with extremely narrow bandwidth. The pass filter can be divided into C-band (1528~1562nm) and L-band (1561~1620nm) edge filters, while C-band edge filter can be divided into the center short-wavelength field (1528~1545nm: commonly known as blue Band) and long wavelength fields (1545~1561nm: commonly known as red band) These two broadband filters.

The center frequency of the bandpass filter changes slightly with temperature, so the temperature stability of the center wavelength of the band poses a problem. This requires that the substrate material used in the band pass filter has a high transmittance in a certain wavelength band (960 to 1600 nm) on the one hand, and the expansion coefficient of the substrate material is matched with the inorganic film on the other hand.

Generally, the substrate used for the optical filter for the camera is plastic. Since the heat resistance of the plastic is not good, the band laser filter is used when strong laser light is incident, and the plastic is prone to deformation and deterioration, so it is necessary to use heat resistance. glass.

If the band pass filter uses amorphous glass as the substrate, since the amorphous glass has low thermal expansion, low mechanical strength, and low surface hardness, the compressive force and durability of the amorphous glass substrate to the inorganic film are insufficient, but if In order to increase the expansion coefficient of amorphous glass, it is necessary to add a large amount of Na ₂ O alkaline components, but the glass contains Na ₂ O, which leads to poor film formation on the glass, and the migration of alkali ions deteriorates the mechanical properties and surface properties of the substrate. , thus limiting its wide application.

The technical problem to be solved by the present invention is to provide a glass ceramic for a multilayer inorganic membrane filter having high mechanical properties.

The present invention also provides a multilayer inorganic membrane filter prepared from the above glass ceramic.

The technical solution adopted by the present invention to solve the technical problem is: glass ceramics, the composition of which comprises: SiO ₂ : 69 to 80%; Li ₂ O: 8 to 12.5%; Al ₂ O ₃ : 4 to 10%; ₂ O ₅ : 1.5 to 3%; ZrO ₂ : 1 to 8%; K ₂ O: 0.5 to 3%; MgO + ZnO + BaO + SrO: 0.5 to 5%.

Glass-ceramic, its weight percentage composition contains: SiO ₂ : 69 ~ 80%; Li ₂ O: 8 ~ 12.5%; Al ₂ O ₃ : 3 ~ 10%; P ₂ O ₅ : 1 ~ 3%; ZrO ₂ : 0.1~8%; K ₂ O: 0.5~3%; MgO+ZnO+BaO+SrO: 0.5~5%.

Further, it also contains TiO ₂ : 0 to 3%.

Further, it also contains TiO ₂ : 0.5 to 3%.

Further, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.05 to 1.2.

Further, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.1 to 0.7.

Further, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.2 to 0.5.

Further, it also contains Y ₂ O ₃ +La ₂ O ₃ +Gd ₂ O ₃ 0 to 3%; Sb ₂ O ₃ +CeO ₂ 0 to 2%.

Further, wherein ZrO _{2 is} 0.1 to 5%; and/or Al ₂ O _{3 is} 4 to 7%.

Further, it does not contain Na ₂ O.

Further, wherein ZrO _{2 is} 0.1 to 2%.

Further, the glass contains lithium disilicate crystals, and at least one of α-quartz crystals, α-cristobalite crystals, and α-quartz solid solution crystals.

Further, the glass ceramic has a coefficient of expansion in a temperature range of -25 ° C to 75 ° C in a range of from 90 × 10 ^-7 / ° C to 130 × 10 ^-7 / ° C.

Further, the glass-ceramics has a Young's modulus of 85 GPg or more.

The glass-ceramic has a hardness of 600 kgf/mm ² or more.

Further, the glass ceramic has a flexural strength of 10 Kg/mm ² or more.

Further, the 10 mm glass piece of the glass ceramic has a transmittance of 80% or more in a wavelength range of 950 nm to 1600 nm.

The multilayer inorganic membrane filter is formed by forming an inorganic film having a multi-layer expansion coefficient larger than that of glass ceramics on the above-mentioned glass ceramics.

The beneficial effects of the present invention are that the glass ceramic of the present invention does not contain harmful components such as PbO or As ₂ O ₃ . It has a high expansion coefficient. Under the application temperature of the multilayer inorganic membrane filter, the refractive index change of the inorganic film can be avoided, the temperature stability of the product can be improved, the mechanical properties are better, the chemical stability is better, and the filter is ensured. It is durable and has a high transmittance in a certain band (960~1600nm).

Fig. 1 is an XRD chart of a glass ceramics of Example 1 of the present invention.

Fig. 2 is a graph showing the transmittance of the glass ceramics of Example 1 of the present invention at a thickness of 10 mm and 960 to 1600 nm.

The reason why the substrate glass ceramics of the multilayer inorganic membrane filter of the present invention limits its composition and content, as well as its expansion coefficient, Young's modulus, hardness, flexural strength, transmittance, and main crystal phase are described below.

The glass substrate of the multilayer inorganic membrane filter provided by the present invention is a glass ceramic having LiO ₂ -Al ₂ O ₃ -SiO ₂ as a system.

The glass ceramic material of the substrate material of the multilayer inorganic membrane filter provided by the invention has a coefficient of expansion in the range of -25 ° C to 75 ° C and a coefficient of expansion in the range of 90×10 ^-7 /° C. to 130×10 ^-7 /° C. The best is in the range of 110~120×10 ^-7 /°C. In the band pass filter, the temperature stability of the central wavelength is related to the temperature coefficient of the refractive index of the multilayer inorganic film, and the refractive index is determined by the atomic density of the film on the multilayer inorganic film. During the film formation process, the band pass filter When the substrate temperature is 200 ° C, the substrate has a large expansion. After the substrate is formed, when the temperature is lowered, since the expansion coefficient of the substrate is larger than the expansion coefficient of the film, the film is subjected to compressive stress, resulting in an increase in the film atom density of the film, and thus the refractive index. It also increases. When the expansion coefficient of the substrate is less than 90×10 ^-7 /°C, the substrate can not give sufficient compressive stress to the film, which promotes the fluctuation of the central wavelength with temperature, which causes the adjacent wavelength to interfere. When the expansion coefficient of the substrate glass is greater than At 140 × 10 ^-7 / ° C, the film will fall off on the substrate, affecting the durability of the filter.

Since the microcrystalline glass substrate is coated with a multilayer film and is required to be processed to be 2 mm×2 mm×2 mm or less, in order to ensure that the glass ceramic substrate is not deformed by the multilayer film and to ensure dimensional stability of the multilayer film, the glass ceramic is required to have The higher the mechanical properties, the Young's modulus of the glass-ceramics of the present invention is required to be 85 GPa or more; the U-type hardness is 600 kgf/mm ² or more, preferably 620 kgf/mm ² or more, and more preferably 650 kgf/mm ² or more. ; flexural strength in 10Kg / mm ² or more, preferably within 15Kg / mm ² or more, more preferably by at 20Kg / mm ² or more.

In the optical communication filter, the substrate has a high transmittance, can reduce the attenuation rate of the light, and can reduce the noise in generating the signal. Therefore, the 10 mm glass-ceramic substrate of the present invention transmits light in the wavelength range of 950 nm to 1600 nm. The degree is 70% or more.

The glass ceramic of the present invention contains lithium disilicate crystal, and at least one of α-quartz crystal, α-cristo quartz crystal, and α-quartz solid solution crystal, and the present invention constitutes the main crystal glass by the above crystal. Crystal phase. After suitable heat treatment, the matrix glass generates lithium disilicate and lithium disilicate crystals, and at least one of α-quartz crystal, α-cristobalite crystal, and α-quartz solid solution crystal, and the glass component in the glass ceramic is passed through The ratio of the crystal component content adjusts the expansion coefficient of the glass ceramic to obtain the glass ceramic of the invention in the temperature range of -25 ° C to 75 ° C, and the expansion coefficient thereof is 90×10 ^-7 /° C. to 130×10 ^-7 / Within the °C range.

SiO ₂ is the most basic component of the crystallized glass of the present invention, and is one of components forming a crystal of lithium disilicate, α-quartz crystal, α-cristo quartz crystal, and α-quartz solid solution crystal, if SiO ₂ The content of the weight percentage (the same below) is below 69%, the crystals formed in the glass ceramics become less and the crystals tend to become coarser, affecting the expansion coefficient and transmittance of the glass ceramics; if the SiO ₂ content is above 80%, the glass is melted. The temperature is high, the material is difficult, and crystals having a large expansion coefficient are formed when crystals are formed, such as a quartz crystal (expansion coefficient of 674×10 ^-7 /K) and α-cristobalite crystal (expansion coefficient of 580×). 10 ^-7 /K), which causes the expansion coefficient of the glass-ceramic to exceed the range of use.

Li ₂ O is an essential component for forming the crystal phase of the main crystal phase lithium disilicate crystal of the present invention. If the Li ₂ O content is less than 8%, the content of the main crystal phase formed in the glass is insufficient, which affects the expansion coefficient of the glass ceramic. The mechanical properties will cause difficulty in melting the base glass; if the Li ₂ O content is above 12.5%, the crystal will easily grow and affect the transmittance of the glass ceramic.

Al ₂ O ₃ can improve the mechanical properties and chemical stability of the glass ceramic of the present invention, and is also an integral part of the α-quartz solid solution crystal. In order to improve the mechanical properties of the glass ceramics, it is necessary to add Al ₂ O ₃ in the above 3%, and further to add Al ₂ O ₃ in the above 4%; if the Al ₂ O ₃ content exceeds 10%, the glass is difficult to melt and easily expands. Crystals with small coefficients, such as β-spodumene and β-cristobalite, will greatly reduce the expansion coefficient of the glass-ceramic, and do not meet the requirements of the glass plate of the band-pass filter. The Al ₂ O ₃ content is preferably from 4 to 7%.

P ₂ O ₅ is a nucleating agent for the glass ceramics of the present invention. The P ₂ O ₅ content is below 1%, the further content is below 1.5%, the nucleation in the glass is too small, the crystal formation in the glass is less, affecting the expansion coefficient of the glass ceramic; if the P ₂ O ₅ content is above 3%, Will reduce the chemical stability of glass-ceramics.

ZrO _{2 is} also a nucleating agent for the glass ceramics of the present invention, and the two nucleating agents are used at the same time, which can make the crystal growth of the glass ceramics become more and smaller, which can better promote the mechanical properties and chemical stability of the glass ceramics. Sexual improvement. The ZrO ₂ content is below 0.1%, which has no effect; the ZrO ₂ content is above 8%, and the melting difficulty of the glass is increased. The content of ZrO _{2 is} preferably 0.1 to 5%, the content of ZrO _{2 is} more than 2%, and the heat treatment temperature range is narrow. If the temperature is inadvertently, the required transmittance of the glass is not required, which is disadvantageous for mass production. The ZrO ₂ content is preferably 0.1 to 2%.

The main function of K ₂ O is to promote the melting of glass and reduce the melting temperature of glass. The addition of small content can prevent the matrix glass (glass before crystallization) from crystallization during molding. If there is crystallization in the matrix glass, it will affect the final crystallite. Uniformity in glass properties; if the K ₂ O content exceeds 3%, unwanted crystals such as potassium feldspar are formed in the glass ceramics, and the crystals in the glass become coarser and larger, thereby affecting the transmittance of the glass. . The content of K ₂ O is 0.5 to 3%.

The role of TiO ₂ in glass is to promote the formation and growth of crystals during heat treatment of matrix glass and increase the coefficient of expansion of glass. However, if the content of TiO ₂ exceeds 3%, the glass tends to have more crystals in the glass during heat treatment, and the glass expands. The coefficient easily exceeds the filter requirement range, so the TiO ₂ content is limited to 0 to 3%, preferably 0.5 to 3%.

The present inventors have found that by reasonably adjusting the content and ratio of TiO ₂ , ZrO ₂ and P ₂ O ₅ in the glass, the crystal inside the glass can be made larger and smaller, and the glass expansion coefficient can be ensured within a desired range. Increasing the hardness of the glass and improving the transmittance of the glass ceramic at 960-1600 nm, therefore, the ratio of TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) in the present invention ranges from 0.05 to 1.2, preferably from 0.1 to 0.7. The better is 0.2~0.5.

La ₂ O ₃ has a remarkable effect on improving the devitrification resistance of the glass. If the content is more than 3%, the glass is easily devitrified. Therefore, the content of La ₂ O ₃ is limited to 0 to 3%.

The main function of Y ₂ O ₃ is to suppress the crystallization of the matrix glass during the glass molding, and to improve the weather resistance of the glass and the hardness of the glass. However, when the content exceeds 3%, the difficulty of melting the matrix glass is increased, and therefore, the content of Y ₂ O ₃ is limited to 0 to 3%.

The role of Gd ₂ O ₃ is to prevent the crystals in the glass from becoming coarse when heat treatment, and to increase the chemical stability of the glass, but when the Gd ₂ O ₃ content is higher than 3%, the devitrification resistance of the glass deteriorates. Therefore, the content of Gd ₂ O ₃ is limited to 0 to 3%.

The main action of Y ₂ O ₃ , La ₂ O ₃ and Gd ₂ O ₃ is to suppress the crystallization of the matrix glass during the glass molding and to improve the weather resistance of the glass. The total content of Y ₂ O ₃ , La ₂ O ₃ and Gd ₂ O ₃ is preferably 3% or less. When the content exceeds 3%, the glass tends to become opaque when the matrix glass is crystallized, and Y ₂ O ₃ The addition of La ₂ O ₃ and Gd ₂ O ₃ hinders the nucleation of the glass, but does not hinder the growth of the crystal.

MgO, ZnO, BaO and SrO act as a co-solvent to help the glass melt, inhibit the crystallization of the matrix glass during glass forming, prevent the crystal structure from growing too thick during the crystallization of the glass, and improve the thermal stability of the glass. Chemical stability. In order to obtain the above effects, the total content of these components is 0.5% or more, and when the total content of these components exceeds 5%, the glass is easily emulsified at the time of crystallization, making the glass opaque.

The Sb ₂ O ₃ and CeO ₂ components were added as a fining agent, and the total content of Sb ₂ O ₃ and CeO ₂ added was 2% or less.

The glass ceramic of the present invention does not contain Na ₂ O because if the glass contains Na ₂ O, the film forming property on the glass is poor, and the migration of Na ions deteriorates the mechanical properties and surface properties of the substrate.

In order to obtain the above glass ceramics, the present invention comprises the above raw material group The glass mixture is smelted and rough annealed to obtain a matrix glass of glass ceramics. The matrix glass is heat treated at a temperature of 500 to 650 ° C for about 1 to 7 hours to form a crystal nucleus, and further crystallized at a temperature of 700 to 780 ° C. The crystal grows up for 6 hours.

The glass ceramics of the present invention are ground and polished to have a roughness on the glass-ceramic substrate of 5.0 A or less, and are alternately formed on the glass-ceramic substrate by deposition, radio frequency ion plating or magnetron sputtering. The refractive index inorganic film and the low refractive index inorganic film form an interference type filter for use in a communication device.

Tables 1 to 3 are Examples 1 to 18 of the present invention, and the table shows the composition, crystal phase composition, expansion coefficient, Young's modulus, hardness, flexural strength and transmittance of the glass ceramics.

First, weigh the ingredients according to the composition weights of Examples 1 to 18 in Tables 1-3. The raw materials may be carbonates, nitrates, oxides, etc., and then weigh all the weighed materials into the V-shaped mixer. After mixing and mixing, it is used as a glass raw material. Then, the prepared glass raw material is put into an electric furnace, melted at a temperature of 1250 to 1400 ° C for 8 hours, and clarified at a temperature of 1450 to 1580 ° C for 10 hours, and then the molten glass liquid is discharged at 1250 to 1300 ° C. The mold was molded, the mold temperature was 200 ° C, and strong air cooling was performed during molding, and the obtained matrix glass was roughly annealed at 680 ° C in a muffle furnace.

The prepared matrix glass is placed in a high temperature furnace for heat treatment, and the heat treatment process includes two stages of crystal nucleation precipitation and crystal growth, wherein the temperature in the muffle furnace is maintained at 500 to 650 ° C in the nucleation stage. For 1-7 hours, the crystal nucleus is generated in the glass as much as possible, and then the temperature in the muffle furnace is raised to about 700-780 ° C to enter the microcrystalline growth stage for 0.5-6 h to obtain the desired glass ceramics. .

The following tests were performed on the obtained glass ceramics:

Crystal phase measurement: The crystallized glass was ground into a powder, and the crystal phase of the glass ceramic was measured by an X-ray analyzer at a scanning speed of 5 K/min and a scanning range of 5 to 90.

The coefficient of thermal expansion α is measured as an average value of -25 to 70 ° C according to the method specified in GB/T7962.16-2010.

Young's modulus is measured according to the method specified in GB/T7962.6-2010.

The hardness is measured in accordance with the method specified in GB/T7962.18-2010.

The bending strength is in accordance with the test method for three-point bending of glass specified in the ASTM C158-02 standard.

Transmittance test: Prepare the glass-ceramics into 40×30×1mm samples and perform two-pass smooth polishing. The surface roughness is Ra=0.012, the flatness is N=3, △N=0.5, and the above 40×30× A 1 mm sample was placed in a Hitachi U-4100 spectrophotometer to test a transmittance of 960-1600 mm.

The above-mentioned glass-ceramics are initially ground with 800~1200# diamond particles or 400~1200 aluminum powder# for 0.5~1h, after coarse grinding, polishing with micron-sized cerium oxide polishing particles for 0.5~1h to make micro-fine The roughness on the crystal glass substrate is 5.0 A or less.

Further, using an ion-assisted vapor deposition device, an electrolyte multilayer film of TiO ₂ /SiO ₂ , Ta ₂ O ₅ /SiO ₂ and Nb ₂ O ₅ /SiO ₂ is alternately formed on the polished glass ceramic to prepare a multilayer film filter. Can be used as a bandpass filter in optical communication.

Claims (18)

A glass ceramic characterized by comprising: SiO ₂ : 69 to 80%; Li ₂ O: 8 to 12.5%; Al ₂ O ₃ : 4 to 10%; P ₂ O ₅ : 1.5 to 3 %; ZrO ₂ : 1 to 8%; K ₂ O: 0.5 to 3%; MgO + ZnO + BaO + SrO: 0.5 to 5%. A glass ceramic characterized by comprising: SiO ₂ : 69 to 80%; Li ₂ O: 8 to 12.5%; Al ₂ O ₃ : 3 to 10%; P ₂ O ₅ : 1 to 3 %; ZrO ₂ : 0.1 to 8%; K ₂ O: 0.5 to 3%; MgO + ZnO + BaO + SrO: 0.5 to 5%. The glass ceramic according to claim 1 or 2, further comprising TiI ₂ : 0 to 3%. The glass ceramic according to claim 1 or 2, which further contains TiO ₂ : 0.5 to 3%. The glass ceramic according to claim 3 or 4, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.05 to 1.2. The glass ceramic according to claim 3 or 4, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.1 to 0.7. The glass ceramic according to claim 3 or 4, wherein TiO ₂ /(ZrO ₂ +P ₂ O ₅ ) is 0.2 to 0.5. The glass ceramic according to claim 1 or 2, further comprising Y ₂ O ₃ +La ₂ O ₃ +Gd ₂ O ₃ 0 to 3%; and Sb ₂ O ₃ +CeO ₂ 0 to 2%. The glass ceramic according to claim 1 or 2, wherein ZrO _{2 is} 0.1 to 5%; and/or Al ₂ O _{3 is} 4 to 7%. The glass ceramic according to claim 1 or 2, which is characterized in that it does not contain Na ₂ O. The glass ceramic according to claim 1 or 2, wherein ZrO _{2 is} 0.1 to 2%. The glass ceramic according to claim 1 or 2, wherein the glass contains a lithium disilicate crystal, and at least at least one of an α-quartz crystal, an α-cristo quartz crystal, and an α-quartz solid solution crystal. One. The glass ceramic according to claim 1 or 2, wherein the glass ceramic has a coefficient of expansion in a temperature range of -25 ° C to 75 ° C of 90 × 10 ^-7 / ° C to 130 × 10 ^-7 / °C range. The glass ceramic according to claim 1 or 2, wherein the glass ceramic has a Young's modulus of 85 GPa or more. The glass ceramic according to claim 1 or 2, wherein the glass ceramic has a hardness of 600 kgf/mm ² or more. The glass ceramic according to claim 1 or 2, wherein the glass ceramic has a flexural strength of 10 Kg/mm ² or more. The glass ceramic according to claim 1 or 2, wherein the 10 mm glass piece of the glass ceramic has a transmittance of 80% or more in a wavelength range of 950 nm to 1600 nm. A multilayer inorganic membrane filter formed by forming an inorganic film having a multi-layer expansion coefficient larger than that of glass ceramics on a glass ceramic according to any one of claims 1-17.