TW201522270A - Flat glass with filtering effect - Google Patents

Abstract

This invention relates to a glass and a method for its production. It is characterized by a particularly steep UV edge and is suitable for many different uses, such as for example as UV filter glass. The glass has excellent filtering properties which are achieved by the use of certain UV filtering components in connection with a reducing melt.

Description

Flat glass with filtering effect

The present invention relates to a flat glass, a method of producing the flat glass, and various applications of the flat glass, and a laminated multilayer structure including the flat glass.

Flat glass, for example, is used as a cover glass in a picture frame or as a cover glass in organic light-emitting diodes (OLEDs). In the prior art, numerous flat glass sheets are known. An example is window glass.

However, conventional flat glass has a fatal disadvantage that makes flat glass unsuitable for certain applications: a high proportion of ultraviolet (UV) radiation can pass through conventional flat glass.

The penetration of ultraviolet radiation from glass is a critical property, depending on the intended application. For example, when a flat glass is used as a cover glass in an organic light-emitting diode, the ultraviolet transmittance is a property that determines the lifetime of the ultraviolet-sensitive emission layer located under the flat glass. For example, the same principle can be applied to paintings that are sensitive to ultraviolet light fixed in a picture frame with flat glass as the cover glass.

There are a lot of glass components that are basically suitable for filtering out some of the ultraviolet light in the light passing through the glass. But for many applications, you need to consider It is not allowed to change the color of light passing through the glass.

That is to say, in many examples of applications, for example, in the case of organic light-emitting diodes, technical applications, shop window glass, painting of return glass or glass, a neutral color appearance is required, especially in Neutral colors are required from different perspectives. In addition, the higher the neutral color of the desired glass, the better, and the ability to protect the color of the paint and/or natural or synthetic fibers, as well as the color of the dye in the shop window, against ultraviolet light.

And, in particular in the case of metal halides or other kinds of gas discharge lamps, also in the case of halogen lamps, in the long term, the proportion of ultraviolet light in conventional sunlight or light causes a certain degree of damage, such as nature. Or fading or embrittlement of synthetic materials.

Even in the glass of an office or residential area, in direct sunlight, in order to greatly reduce the fading of wood surfaces, curtains, padded furniture, etc., it is still necessary to protect against ultraviolet light. Thus, for example, passive application improvement of solar energy has been promoted. Current heat-resistant glass contains a thin layer of silver that does not have any non-reflective effect in the visible range and does not provide sufficient UV protection because ultraviolet light can penetrate that thin layer of silver.

Conventional non-reflective soft glass is formed by using an organic polymer as an absorber of ultraviolet light to form ultraviolet protection. For example, in a laminated glass, two glass panes are pressed together by means of a PVB plastic foil (for example, about 380 micrometers (μm) thick), wherein the refractive index of the plastic foil can be adjusted by glass. . However, for example, such a glass is under intense light, and the lampshade of the lamp is unstable to temperature and degraded under intense ultraviolet radiation. In addition, the coating of their respective one-sided three-layer anti-reflection is subject to the above limitations, and further, the pressure The manufacture of glass is also very laborious.

Another possibility is the application of UV absorption, such as a few micron thick paint layers that are semi-transparent to visible light. Such lacquer layers are not very stable to ultraviolet light and temperature, and must be rendered non-reflective after application of the lacquer layer to the glass.

The following reference teaches flat glass suitable for use as an organic light-emitting diode protective glass application. However, no flat glass provides effective protection against ultraviolet light and is also colorless.

US 2010/0300535 A1 teaches a glass containing sodium. For example, such glass can be used as a substrate glass in solar photovoltaic applications. This is a flat glass. The described glass has a very low melting point, making it easier to manufacture. The glass described in this reference does not have the excellent ultraviolet filtering properties of the flat glass as in the present invention. The reason is in particular that the glass has not melted in a reducing environment and the glass is free of cerium.

US 2006/0006786 A1 describes a glass for use as a gas discharge tube in a lamp. The glasses described herein are disclosed in a wide range. The contents of alkali metal oxides and alkaline earth metal oxides are similar to those in the glass of the present invention. However, the glass contains palladium, rhodium, platinum or iridium. Most preferably, the glass of the present invention does not contain these ingredients. Furthermore, it is not apparent from the literature of the prior art that the benefit of the choice of elements for cobalt (Co), titanium (Ti) and cerium (Ce) can be achieved. More titanium dioxide (TiO ₂ ) and a very small amount of cerium oxide (CeO ₂ ) are used. Furthermore, the glass does not melt under reducing conditions.

US 2010/0047521 A1 describes a glass that can be used as a cover glass in an electronic device. The glass is transparent under infrared radiation. The glass described in this reference does not have the excellent UV filtering properties of the glass of the present invention because the glass does not contain bismuth and does not melt under a reducing environment. Further, the glass contains a large amount of alumina (Al ₂ O ₃ ), so that the glass tends to be easily crystallized.

US 2009/0325776 A1 describes a glass comprising a specific amount of β-OH. For example, the glass can be used as a cover glass for electrical appliances. Here, cerium oxide is used as a refined preparation, but cerium oxide can be used as a refined preparation only under oxidizing conditions. Therefore, the glass described does not have the ultraviolet filtering properties of the glass of the present invention. Furthermore, the glass disclosed in this document has a high alumina content.

EP 0 939 060 A1 describes a substrate glass for a display. The glass discussed herein is not a filter glass. In addition, a high amount of alumina is used. Ultraviolet filter glass cannot be obtained because of the use of an oxidizing fine preparation (sulfur trioxide (SO ₃ ), arsenic trioxide (As ₂ O ₃ ), antimony trioxide (Sb ₂ O ₃ )), and does not use ultraviolet-filtered elements. .

For flat glass, there is a need for a glass that can be manufactured inexpensively on the line and has a filtering effect. For example, such methods as floating, draw up, down draw, and overflow fusion. In all of these methods, it is important that the glass exhibits high resistance to crystallization and that the glass does not contain a high proportion of reduction sensitive elements. This makes the formulation of the respective glass compositions more complicated. The glass processed by the above method must be stored at a high temperature for a long time, and thus may cause crystallization. Many conventional glass are cast into blocks or other shapes that can be cooled quickly to avoid crystallization.

Accordingly, it is an object of the present invention to provide a flat glass suitable for The ultraviolet sensitive material is protected from incident ultraviolet light, and it is optimal that the visible light portion passing through the glass is changed almost or completely.

This goal can be achieved by the subject matter of the patent application.

The flat glass of the present invention comprises at least 60% by weight and up to 76% by weight of cerium oxide. Ceria is a network former. Cerium oxide provides the required chemical impedance and is used to adjust the viscosity properties. The flat glass should be the glass that is "longer". This means that the viscosity changes slowly with temperature. Therefore, the glass melt is easily maintained within a moldable viscosity range. When the amount of cerium oxide is too small, the chemical resistance of the flat glass is insufficient. Most preferably, the cerium oxide content is at least 64% by weight, and the optimum weight percentage is at least 65.5%, especially the optimum weight percentage is at least 66%. The weight percentage of the content of this element is preferably at most 74%, and especially the weight percentage is preferably at most 72%.

The flat glass of the present invention comprises one or more alkali metal oxides in a proportion of at least 6% by weight and at most 25% by weight. The alkali metal oxide acts as a fluxing agent during melting and can reduce the viscosity of the glass melt. Therefore, alkali metal oxides are important for the production of flat glass, and in particular, it makes the molding process more convenient. Because the size of the alkali ions is small and the mobility is extremely large, on the one hand, the chemical curing of the glass is feasible, but on the other hand, the chemical resistance of the flat glass is also affected. Therefore, the content of alkali metal oxide should be carefully selected. In a preferred embodiment, the flat glass of the present invention comprises an alkali metal oxide in an amount of at least 8% by weight, most preferably at least 10% by weight, and especially preferably at least 12.5% by weight. The content is preferably not more than 21% by weight, and particularly preferably not more than 18% by weight, otherwise the effect on chemical resistance is too great. According to the invention, the alkali metal oxide is preferably lithium oxide (Li ₂ O), sodium oxide (Na ₂ O) and potassium oxide (K ₂ O). In the preferred embodiment, only sodium oxide and/or potassium oxide are used. Lithium significantly reduces chemical impedance. Most preferably, the proportion of sodium oxide is higher than the ratio of potassium oxide.

The optimum ratio of sodium oxide used is at least 5% by weight and up to 15% by weight. In particular, the optimum range is from 8% to 12.5% by weight. The optimum use ratio of potassium oxide is at least 1% by weight and up to 10% by weight. In particular, the optimum range is from 3.5% to 7% by weight.

The flat glass of the present invention further comprises one or more alkaline earth metal oxides in a proportion of at least 1% by weight and at most 21% by weight. Similar to the case of an alkali metal oxide, an alkaline earth metal oxide can be used as a viscosity to adjust and a temperature to lower the melting point. However, the chemical impedance is not greatly affected as compared with the use of an alkali metal oxide. Most preferably, the flat glass comprises an alkaline earth metal oxide in an amount of at least 4% by weight and up to 15% by weight. According to the present invention, the term "alkaline earth metal oxide" is preferably represented by magnesium oxide (MgO), calcium oxide (CaO), barium oxide (BaO) and barium oxide (SrO), and is preferably calcium oxide and oxidation. Antimony and antimony oxide, and especially preferred are only calcium oxide and antimony oxide. According to the glass of the present invention, the proportion of the alkaline earth metal oxide is preferably lower than the ratio of the alkali metal oxide. The content of calcium oxide is preferably higher than the content of cerium oxide and/or zinc oxide.

The optimum weight percentage of the proportion of calcium oxide contained in the glass is at least 1% and at most 10%. Most preferably, the weight percentage used is at least 2.5%, at most 9%, and more preferably at least 3.5% by weight, up to 7% by weight. According to a preferred embodiment of the flat glass of the present invention, the proportion of cerium oxide is weight The percentage is at most 6%, and the best is at most 4.5%. Still more preferred embodiments comprise at least 1% by weight or at least 3% by weight.

Especially with regard to the good results of the viscosity of the melt, the melting period behavior and chemical resistance can be obtained. When the sum of the alkali metal oxides and the sum of the alkaline earth metal oxides, the mass ratio of the two is less than 2, and most preferably higher than 1.5.

The flat glass of the present invention may comprise alumina in a proportion of up to 6% by weight. Alumina is a mesh former, which increases chemical resistance and increases the hardness of flat glass. Further, when used together with an alkali metal oxide, chemical curing of the flat glass can be facilitated. However, when the amount is too large, this element tends to increase the crystallization of the glass, making the manufacture of the glass more complicated. Overall, it may weaken the melting period behavior. In a preferred embodiment, the glass comprises alumina in a proportion of at least 0.5%, at most 3.5% or less than 3% by weight.

According to the invention, the sum of both the cerium oxide and the aluminum oxide element is preferably at most 75% by weight, more preferably at most 74%, particularly preferably at most 72%, and most preferably at most 70%. When the number of these elements used is too large, the melting period behavior is impaired, resulting in an increase in manufacturing costs.

Most preferably, the glass contains only a small amount or no boron oxide (B ₂ O ₃ ). The content by weight of boron oxide is preferably less than 5%, more preferably less than 2%, and particularly preferably less than 0.5%.

Most preferably, the glass contains only a small amount or no phosphorus oxide (P ₂ O ₅ ). The content of phosphorus oxide is preferably less than 5% by weight, more preferably less than 2%, and most preferably less than 0.5%.

The flat glass of the present invention may comprise a proportion by weight of zinc oxide of 4%. Zinc oxide functions like an alkaline earth metal oxide, but it also There is a tendency to reduce crystallization, which is why some embodiments do not use zinc oxide. Other embodiments of the invention comprise a zinc oxide weight percent ratio of at least 1%, more preferably at least 1.5%, and at most 3.5%. The weight percentage of the elemental magnesium oxide, cerium oxide, cerium oxide and zinc oxide is not more than 20%, and most preferably not more than 12%, especially preferably not more than 10%. Preferably, however, the content is at least 4% by weight and most preferably at least 5.5%. These numbers have been shown to be particularly effective in adjusting viscosity and melting properties.

The flat glass of the present invention contains ruthenium. This element is preferably added to the mixture in the form of cerium oxide; however, it is also possible to add cerium (III) which is already in an oxidized state, such as cerium chloride (CeCl ₃ ), cerium nitrate (Ce(NO ₃ ) ₃ ) or cerium oxide ( Form of Ce ₂ O ₃ ). The content of the flat glass of the present invention is in the form of cerium oxide. When other types of hydrazine are used, the amount of these other types of hydrazine will correspond to the amount of cerium oxide used (in moles). Ce ³⁺ and Ce ⁴⁺ act as ultraviolet radiation absorption. Tantalum is a key point in the UV absorber in flat glass because an incorrect oxidation state and/or too high a concentration of tantalum can cause yellowing tones. For this reason, the cerium oxide used in the flat glass of the present invention is preferably limited to a weight percentage of at most 8%, most preferably at most 5%, and most preferably at most 4%. When the composition of the glass also contains titanium dioxide, Ce ³ -O-Ti ⁴⁺ may combine to cause flattening of the ultraviolet edges. When the term "铈" is used in this specification, this represents all the oxidation states of the element. The glass of the present invention is produced under reducing conditions relative to the glass of the prior art. In this way, the ratio of Ce ^{3+ in the} glass relative to Ce ⁴⁺ can be increased. Manufactured under reducing conditions, with only a low proportion of bismuth, a very good UV radiation absorption effect can be achieved.

The weight percentage of cerium oxide added is preferably at least 0.1%, The optimum weight percentage is at least 0.3%, more preferably the weight percentage is at least 1%, especially preferably at least 2%. In order to achieve a particularly advantageous UV edge, the amount of niobium required is also related to the thickness of the flat glass. When the element 铈 is used in an amount corresponding to the cerium oxide content (weight percentage 2.5% + d * weight percentage 0.1%) ± weight percentage 0.5%, where d is the thickness of the flat glass, the unit is centimeter (millimeter), known Particularly advantageous. Therefore, in the example having a thickness of 2 cm, the respective cerium oxide content is preferably 2.5% by weight + 2 * weight percent 0.1% = 2.7% by weight (± 0.5% by weight).

In order to make the ultraviolet edge of the flat glass of the present invention as steep as possible, the flat glass is melted under reducing conditions. Therefore, a large part of Ce ⁴⁺ from cerium oxide becomes Ce ^{3+ in an} oxidized state. The maximum absorption of Ce ⁴⁺ occurs at approximately 280 nanometers (nm), while Ce ³⁺ occurs at approximately 315 nm. By reducing the melting conditions, adjusting the ratio of Ce ³⁺ to Ce ⁴⁺ to more Ce ³⁺ has been shown to be helpful in achieving particularly steep UV edges. Unfortunately, the ratio of Ce ³⁺ to Ce ⁴⁺ in the glass according to the present invention cannot be quantitatively measured with sufficient reliability. However, the correct ratio of these two elements can be well detected by relying on the penetration spectrum of the glass, especially under the steep ultraviolet edge.

The optimum reduction melting conditions can be achieved by adding a reducing agent to the mixture. The optimum weight percentage of the reducing agent used is 0.8%, more preferably 0.5% by weight. Most preferably, a reducing agent is added to the glass mixture prior to the melting step. The preferred reducing agent weight percentage is at least 0.01%, more preferably 0.1%, and most preferably 0.25%. The most preferred reducing agent is carbon-containing elements and metals. The most preferred carbonaceous elements are carbon (such as coal, especially charcoal), sugar, starch and cellulose. Especially prefer to use carbon because in the melting step, carbon It can be completely burned, so it rarely or hardly remains in the finished flat glass. The best metals are aluminum and tantalum.

The correct amount of cerium oxide and other glass elements are selected, as well as a suitable reduction melting step, and the flat glass according to the present invention achieves good ultraviolet absorption and steep ultraviolet ray edges.

The steepness of the ultraviolet edge of the flat glass according to the present invention is characterized by a first wavelength λ _25% (where the flat glass transmittance is 25%) to a second wavelength λ _65% (the flat glass transmittance is 65%) The distance Δ is at most 100 nanometers (nm). Most preferably, Δ is at most 50 nm, and most preferably at most 25 nm, more preferably at most 15 nm, especially preferably at most 13 nm.

The thickness of the transmittance is measured to be the thickness of the flat glass, which is preferably at least 0.1 cm, more preferably at least 1 cm, and particularly preferably 1.5 cm. The thickness is preferably at most 5 cm and most preferably at most 4 cm. Particularly in the preferred embodiment, the thickness is about 2 cm, 3 cm or 4 cm. In particular, the following calculations for wavelengths use nanometers: λ _25% < λ _65% . The wavelengths of the wavelengths λ _25% and λ _65% are optimal in the region of the boundary between the ultraviolet and visible light, especially in the wavelength range of 400 nm, and preferably up to 390 nm. The optimum range of wavelengths λ _25% and λ _65% is at least 300 nm, and most preferably at least 340 nm.

Most preferably, λ _{25% is} in the wavelength range from 340 nm to 400 nm, and most preferably between 350 nm and 380 nm, especially between 355 nm and 370 nm. Most preferably, λ _{65% is} in the wavelength range between 360 nm and 400 nm, most preferably between 365 nm and 395 nm, and especially preferably between 370 nm and 390 nm.

The UV edge happens to be between the wavelengths λ _25% and λ _65% . Therefore, when λ _25% is 360 nm and λ _65% is 380 nm, it is mentioned in the specification that the ultraviolet edge of the glass is at 370 nm. Most preferably, the ultraviolet edge is in the range of 300 nm to 400 nm, preferably between 340 nm and 394 nm, more preferably between 350 nm and 390 nm, especially in 360 nm to 380 nm.

To mask the moderately yellowing hue that occurs at random, 0.001% by weight of cobalt oxide is used. When the amount of cobalt oxide is too much, the glass becomes an undesired blue color. In a preferred embodiment, the cobalt oxide is used in an amount of at least 0.0001% by weight. Since cobalt oxide is used to compensate for the arbitrarily occurring medium yellowing hue (from the contained yttrium), the correct amount of cobalt oxide is also related to the amount of ruthenium. Most preferably, the cobalt oxide content is not more than one thousandth of the cerium content.

In order to prevent the yellowing hue of the glass, it is preferred according to the invention that the content of rhodium relative to titanium dioxide is relatively low. Most preferably, the titanium dioxide content is at most 1/1000 of the cerium content. In some preferred embodiments there is no titanium dioxide at all.

In the visible range, such as from 400 nm to 780 nm, the flat glass is highly transparent and color neutral. Most preferably, in this wavelength range, the glass has a continuous penetration of at least 85% when the thickness is 2 cm or even 4 cm. Most preferably, the flat glass of the present invention has a color rendering index (Ra) of at least 99%, especially preferably even 100%, and thus is preferably color neutral. The color rendering index will be determined according to DIN 6169, part 2.

In the wavelength range of 280 nm to 350 nm, in terms of thickness of 2 to 4 cm, the transmittance of ultraviolet radiation of the flat glass is preferably not more than 20%, and most preferably not more than 10%, more preferably Not more than 5%, especially the best is No more than 1%.

In the case of a thickness of 2 cm, in the wavelength range of 300 nm to 350 nm, the ultraviolet transmittance is preferably not more than 10%, preferably not more than 5%, and more preferably not more than 1%, especially Good is no more than 0.1%. In the case of a thickness of 2 cm, in the wavelength range of 300 nm to 380 nm, the ultraviolet transmittance is preferably not more than 20%, and most preferably not more than 18%, particularly preferably not more than 16%.

The flat glass of the present invention may contain zirconium dioxide (ZrO ₂ ) in an amount up to 2000 ppm because of the groove material used.

Most preferably, the flat glass of the present invention does not contain titanium dioxide. Titanium dioxide greatly reduces the steepness of the UV edge, especially in the case of use with ruthenium. In addition, the flat glass is preferably free of elements such as lead oxide (PbO), arsenic oxide (As ₂ O ₃ ) and/or strontium oxide (Sb ₂ O ₃ ), which are harmful to the body. Furthermore, it is preferred that no other colored elements are included, especially that the glass does not contain copper, manganese and/or chromium compounds. It is also preferable that the glass does not contain potassium oxide (Er ₂ O ₃ ), nickel oxide (NiO), yttrium oxide (Yb ₂ O ₃ ), bismuth oxide (Bi ₂ O ₃ ), yttrium oxide (Nd ₂ O ₃ ), Cerium oxide (Pr ₂ O ₃ ), niobium oxide (Nb ₂ O ₃ ), tantalum oxide (Ta ₂ O ₅ ), selenium oxide (SeO ₂ ), molybdenum oxide (MoO ₃ ) and/or antimony oxide (GeO ₂ ). Optimally, the glass also does not contain platinum, enamel and enamel.

When it is mentioned in the specification that the glass has no element or the glass does not contain a special element, this means that the element is only an impurity in the glass. This means that the element is not added to the glass in the base amount. According to the invention, the optimum amount of the non-base amount is less than 100 ppm, preferably less than 50 ppm, more preferably less than 10 ppm.

The optimum thickness of the flat glass of the invention is as thin as 10 cm Preferably, the glass has a thickness of at most 2 cm, more preferably 800 microns, still more preferably at most 600 microns, more preferably at most 400 microns, and most preferably at most 300 microns. The flat glass of the present invention has a good ultraviolet radiation filtering function even at a very thin thickness. Moreover, in the case of these thicknesses, the flat glass still has sufficient flexibility. For example, it is sufficient for use in an organic light-emitting diode.

The flat glass of the present invention can be used as a filter glass. The application as a filter glass is to fix the glass in front of an object that is sensitive to ultraviolet light. For example, it is fixed before an organic light-emitting diode, an electronic component such as a CCD, or a drawing. More advantageous applications, such as display glass, especially for tablets, mobile phones, smart phones, screens, televisions, laptops, personal digital assistants (PDAs) and navigation devices. For use in the field of external lighting or in the automotive sector, for example, according to the invention, glass can be used to cover the indicating instrument. In particular, the laminated multilayer structure according to the invention, for example, the organic light-emitting diode comprises at least one further layer in addition to the flat glass according to the invention as a cover glass. Also in products such as organic light-emitting diodes, cell phones, computers, tablets, screens, television sets or the like, flat glass according to the present invention is included as a cover glass in accordance with the present invention.

In accordance with the present invention, in applications where glass is used as a thermal protective glass, it is used in display cases, glass display windows, and office windows. Glass is suitable for a variety of applications. When the glass is often cleaned, especially with a strong cleaning agent, no unnecessary coating is required to provide a filtering effect, so there is no need to worry about the damage caused by the cleaning step.

Glass is suitable for use in painting, for example, in museums. But it can also be used in shop window glass and restoration glass. In addition, the glass is also suitable Provides the ability to paint colors, and/or natural or synthetic fiber protection systems, as well as dyes in shop windows that protect against UV light.

The flat glass of the present invention may also be coated with a multi-functional coating such as an anti-reflective layer, an infrared reflective thermal protective coating, an easy to clean coating and/or an indium tin oxide (ITO) layer. The reflection of the glass is less than 1%. In its alternative, the layer may be applied by cathode evaporation (e.g., sputtering), by physical vapor deposition, or by chemical weather deposition (especially plasma assist).

Thermal protective glass is based on the principle of infrared thermal radiation reflection, by a thin, electrically conductive coating that is primarily transparent in the visible light spectrum. As the heat reflective coating, the most preferable layer is to use tin oxide and silver as a substrate. After the glass is fabricated, as well as a precoating application for diffusion/blocking of cerium oxide (SiOx), the tin dioxide can be applied at a temperature of about 600 ° C, a cooled phase, by means of a spraying process. The layer is approximately 300 nanometers thick, and by doping fluorine or antimony, the sheet resistance can reach 15 ohms, so that in the 300K heat radiation distribution, the average value of the reflected infrared coefficient is greater than 80%. Thus, as a window glass, the glass can reflect a substantial portion of the thermal radiation back into the room of the building.

Instead of doped tin dioxide SnO ₂ :F, it is also possible to use bismuth (Sb), a transparent semiconductor material zinc oxide, ZnO:Al (doped with aluminum) and indium oxide In ₂ O ₃ : Sn (doped with tin, indium tin oxide). However, the electrochemical stability of indium tin oxide is relatively low compared to tin dioxide, and post-treatment is required after the spraying process, and zinc oxide cannot be produced by a sufficiently electrically conductive spraying process.

The heat reflective coating of the substrate is silver forming a relatively good sheet resistance of less than 1 ohm, so the infrared emissivity is 9 to 4%, and the ratio of the extreme example can be as low as 2%. Therefore, a K value of 1.1 to 1.4 W/m ² K is feasible on the basis of this coating pane in a double-glazed, insulated glass structure. In this example, the visible light transmittance is at most 76%, and in the case where the K value is less than 1.0 W/m ² K, the thicker silver layer, the visible light transmittance is as low as about 68%. The UV transmittance is 36 to 19%.

A more advantageous silver layer deposition associated with heat reflection is performed after the preparation of the glass by vacuum coating. This method is a very laborious process in which both sides of the silver layer are also coated with a dielectric layer, as well as an optional metal layer, which increases the transmittance and long-term stability. The disadvantage is that the pressed silver layer structure can only be used inside the double-glazed insulating glass, so the long-term stability of mechanical and chemical properties during the cleaning process cannot be guaranteed.

However, the traditional thermal protection glass still has a UV transmittance of 25%. After the use of the glass according to the invention, especially when using a glass having a thickness of about 4 cm, the UV transmittance of the heat-protecting glass in use can be reduced to <15%. The thicker the glass, the lower the UV transmittance.

Glass can also be used in glass display windows or as window glass.

The flat glass of the present invention can be obtained according to the method proposed by the present invention, in which the elements contained in the glass are mixed together and melted. In the step of melting, it is set to a reduced state, and a reducing agent can be added to the mixture to reach a reduced state.

After the melting step, on-line manufacturing, the glass is optimally processed into flat glass. The respective methods are preferably selected from the following methods, the upper method, the float method and the overflow melting method, or other suitable thin glass thermoforming methods, such as rolling.

After the process of the post-treatment step, the glass can be pressed, coated and/or thermally or chemically tempered.

The rupture strength can be effectively increased by the tempering step. The best coating according to the invention is an anti-reflective and/or anti-fingerprint coating wherein these coatings further reduce the UV transmittance.

Figure 1 depicts three penetration spectra of a glass in accordance with the present invention. It can be seen that the transmittance of the three glasses is greater than 90% over the entire visible range. The transmittance over the entire visible range is constant such that the color impression of light passing through the glass is not altered. According to the invention, the three depicted spectra of glass having the same composition. However, the sample thicknesses studied were different. The thickness of the sample increases from left to right: the spectrum on the left belongs to a sample with a thickness of 2 cm, the spectrum in the middle belongs to a sample with a thickness of 3 cm, and the spectrum on the right belongs to a sample with a thickness of 4 cm. Therefore, the edge of the ultraviolet ray slightly shifts to the direction of the visible light wavelength on the right side as the thickness of the sample increases.

Figure 2 depicts a transmittance curve in which the steepness value Δ of the transmittance curve is plotted. The steepness of the ultraviolet edge of the flat glass according to the present invention is characterized by a first wavelength λ _25% (the glass transmittance is 25%) to a second wavelength λ _65% (the glass transmittance is 65%) The distance △ is very small.

Figures 3 and 4 illustrate that the ultraviolet edge of the glass according to the present invention is very steep. In particular, it appears on the glass B1 to B4. The ultraviolet edge of the glass B6 appears at a shorter wavelength than the glass of the other examples.

Figure 5 shows a coating of a layer of glass B1 having a thickness of 2 cm according to the present invention. The antireflection layer measures the reflectance characteristics between 380 nm and 780 nm in the visible range. The residual reflectance is less than 1% and the ultraviolet transmittance is less than 16%.

Figure 6 depicts the transmittance spectrum of a glass in accordance with the present invention over a wavelength range of 280 to 800 nm. Example 1 according to the examples was prepared by anti-reflection coating.

example

A mixture having the following composition by weight was provided and melted into the glass: in the method of flat glass, the mixture according to Table 1 was processed into a flat glass.

According to Table 2, the glass composition obtained is:

Table 3 shows some measurements of the glass that have been measured.

Claims (11)

A flat glass with the following weight percentage elements: Wherein, the glass has an ultraviolet edge, and the steepness of the ultraviolet edge is characterized by a first wavelength λ _25% (the flat glass transmittance is 25%) to a second wavelength λ _65% (the flat glass transmittance is The distance at 65%) is Δ up to 100 nm (nm). The flat glass of claim 1, wherein the glass has a content of sodium oxide (Na ₂ O) of 5 to 15% by weight. The flat glass of claim 1 or 2, which has a weight percentage of potassium oxide (K ₂ O) of from 1 to 10%. A flat glass according to any one of claims 1 to 3, which has a weight percentage of calcium oxide (CaO) of from 1 to 10%. A flat glass according to any one of claims 1 to 4, wherein the glass is thermally or chemically tempered. The flat glass of any one of claims 1 to 5, which has a weight percentage of cerium oxide (CeO ₂ ) of 0.1 to 5%. A flat glass according to any one of claims 1 to 6, wherein The glass has been melted under a reducing condition, in particular by adding a reducing agent which is up to 0.8% by weight, for example carbon. A flat glass according to any one of claims 1 to 7, which has an ultraviolet ray edge in a wavelength range of 300 to 400 nanometers (nm). A method of filtering glass, the filter glass according to any one of claims 1 to 8, which comprises the steps of: a. providing a glass mixture; b. melting the glass mixture; c. A flat glass is prepared in which a reducing agent is added to the glass mixture. An application of a filter glass as in one of claims 1 to 8 of the patent application, which is used as a UV filter glass. A laminated multi-layer structure comprising the filter glass according to any one of claims 1 to 8, which is used as a cover glass.