WO2017185297A1 - Light guide plate glass - Google Patents

Abstract

Light guide plate glass expressed on the basis of the following oxides by mass percentage, comprising the following components: 55%-75% of SiO₂, 1%-10% of Al₂O₃, 0%-15% of B₂O₃, 5%-15% of R₂O, 10%-20% of MO, 0%-10% of ZnO, 0%-5% of ZrO₂, and 0%-2% of rare-earth oxide, wherein R₂O is selected from at least one of a group consisting of Li₂O, Na₂O, and K₂O, and MO is selected from at least two of a group consisting of CaO, SrO, and BaO.

Description

Light guide plate glass Technical field:

The present invention relates to a light-conducting material, and more particularly to a light guide plate glass.

Background technique:

The side-entry backlight module is generally designed to be incident on the bottom side LED. The most critical part in the entire backlight module is the light guide plate, which functions as a surface light source that turns a line source or a point source into a light source. To obtain a high-quality display, the uniformity of the light emitted by the backlight is very important. The light guide is the key optical component for this purpose. It can direct the light to the desired direction to achieve the required brightness and uniformity. . The technology is derived from the principle of total reflection of optics. For transparent materials with a refractive index greater than 1, the light propagating inside them will be totally reflected, so that light will be emitted from one side of the sheet into the interior of the sheet and then from the other side. The design of the microstructure on the surface of the light guide plate can destroy the total reflection of the light, so that most of the light is emitted perpendicularly to the plane of the light guide plate.

At present, the mainstream white LED is composed of blue LED + yellow phosphor, which is the most common and mature technology. Since the peak of the blue excitation spectrum is between 440 and 480 nm, the peak of the yellow-green region in the emission spectrum is between 530 and 580 nm, and the most sensitive visible wavelength of the human eye is around 550 nm. Therefore, it can be used in the visible light range at a wavelength of 400 nm. The ratio of transmittance T ₄₀₀ to T ₅₅₀ , combined with the ratio of the transmittance T ₄₅₀ to T ₅₅₀ of the ₄₅₀ nm peak of the blue excitation center, is combined to evaluate the optical properties of the material of the light guide: T ₄₀₀ /T ₅₅₀ and The higher the T ₄₅₀ /T _{550, the} higher the spectral reduction of the white LED. However, the PMMA light guide plate not only has the problem of yellowing during the hot working process, but also T ₄₅₀ /T _{550 is} generally not higher than 99.5%, and T ₄₀₀ /T _{550 is} generally not higher than 98%. Although such attenuation is not obvious, and the sensitivity of the human eye to purple light is weak, as the size of the display increases, the light path is magnified dozens of times after multiple times of total reflection, which easily causes the far source region and the near source. The gamut deviation of the area is increased, which has a serious negative impact on the design and process adjustment of the microstructure and ink structure of the light guide plate.

Summary of the invention:

Based on this, it is necessary to provide a light guide plate glass having better optical properties.

A light guide plate glass, the light guide plate glass being expressed by mass percentage of the following oxide standard, comprising the following components:

55% to 75% SiO ₂ , 1% to 10% Al ₂ O ₃ , 0 to 15% B ₂ O ₃ , 5% to 15% R ₂ O, 10% to 20% MO, 0% ～10% ZnO, 0% to 5% ZrO ₂ and 0 to 2% rare earth oxide;

Wherein the R ₂ O is at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O, and the MO is selected from at least two of CaO, SrO, and BaO.

The light guide plate glass is aluminosilicate glass, and the aluminosilicate glass has high strength and good rigidity, and the elastic modulus is generally 20 times or more of the PMMA material. Under the same thickness, the rigidity of the glass light guide plate is PMMA guide. More than 20 times of the light plate can be used to eliminate the structural support when applied to the backlight module, simplifying the structure of the backlight module; the aluminosilicate glass has good thermal stability, weather resistance and chemical stability, in its normal working range and Under the environmental conditions, the thermal expansion and hygroscopic expansion are small, and the display effect and structural support are not affected; the transmittance of the light guide plate glass is 2.5 mm, and the transmittance in the visible wave number is 380 nm to 780 nm is greater than 92%. The internal transmittance is greater than 99%, the refractive index n _{D is} greater than 1.49, the transmittance T ₄₀₀ /T _{550 is} greater than 99%, and T ₄₅₀ /T _{550 is} greater than 99.5%.

detailed description

The light guide plate glass will be further described in detail below mainly in conjunction with specific embodiments.

The light guide plate glass of one embodiment is expressed by mass percentage based on the following oxides, and includes the following components:

55% to 75% SiO ₂ , 1% to 10% Al ₂ O ₃ , 0 to 15% B ₂ O ₃ , 5% to 15% R ₂ O, 10% to 20% MO, 0% ～10% ZnO, 0% to 5% ZrO ₂ and 0 to 2% rare earth oxide;

Wherein R ₂ O is at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O, and MO is at least two selected from the group consisting of CaO, SrO, and BaO.

Silica (SiO ₂ ) is an important glass forming oxide. SiO ₂ can lower the thermal expansion coefficient of glass and improve the thermal stability, chemical stability, softening point, mechanical strength and ultraviolet light transmission ability of the glass. The content of SiO ₂ is suitably from 55 to 75% by weight, preferably from 60 to 72%, particularly preferably from 65 to 70%. When the content is high, a higher melting temperature is required, and the crystallization tendency tends to increase, and the excessive SiO ₂ raw material specific gravity causes the Fe content to be high, eventually affecting the optical properties of the glass.

Al ₂ O ₃ is an intermediate oxide, which can reduce the crystallization tendency of the glass, improve the chemical stability, mechanical strength and refractive index of the glass, and can reduce the erosion of the refractory by the molten glass. The content of Al ₂ O ₃ is suitably from 1 to 10% by weight, preferably from 1 to 7%, particularly preferably from 2 to 5%. High content of Al ₂ O ₃ easily leads to an increase in the melting temperature of the glass, but it can also reinforce the degree of glass network connection, can obtain a lower coefficient of thermal expansion, and has a higher content of Al ₂ O ₃ and requires higher melting. The temperature, and generally the introduction of Al ₂ O ₃ into the feldspar mineral raw material is beneficial to the melting of the glass batch material, but the heavy metal component in the feldspar mineral is not stable enough to easily adversely affect the optical properties of the glass.

The light guide plate glass is aluminosilicate glass, and B ₂ O ₃ forms a structural network together with the silicon oxytetrahedron in the silicate glass system, which can reduce the expansion coefficient of the glass, improve the thermal stability and chemical stability of the glass, and enhance The refractive index of the glass and the gloss of the glass are improved, but are not essential ingredients. B ₂ O ₃ can promote the melting at high temperature, reduce the high temperature viscosity of the glass, and increase the viscosity of the glass at low temperature to form more [BO ₄ ] tetrahedron in the glass network structure, which can effectively improve the thermal stability of the glass. However, if the content is too high, the refractive index is easily lowered, which is not conducive to the total reflection conduction of light. The content of B ₂ O ₃ is suitably from 0 to 15% by weight, preferably from 0 to 7%, and the content of B ₂ O ₃ can be determined according to the content of different alkali metals and alkaline earth metals. B ₂ O ₃ is not an essential component and is generally introduced in a certain amount when a glass having a lower coefficient of thermal expansion is required. When the amount of B ₂ O ₃ introduced is too high, the "boron abnormality" phenomenon easily occurs due to an increase in the boron oxygen triangle.

R ₂ O is a glass network outer body oxide, which can provide free oxygen. The O/Si ratio in the glass structure increases, and the bond breaks, so that the viscosity of the glass can be lowered, and it is the main flux in the raw material component. However, R ₂ O increases the coefficient of thermal expansion of the glass, reducing the thermal stability, chemical stability, and mechanical properties of the glass. The content of R ₂ O is preferably from 5 to 15% by weight, preferably from 5 to 13%, particularly preferably from 5 to 11%. Higher levels of Li ₂ O can effectively lower the high temperature viscosity of the glass, but it is more expensive as a raw material.

CaO is a network external oxide, which acts as a stabilizer in the glass structure of the light guide plate to improve the chemical stability and mechanical strength of the glass. The content of CaO is suitably from 3 to 12% by weight, preferably from 5 to 10%, particularly preferably from 5 to 8%. When the content of CaO is high, the crystallization tendency of the glass is increased, and the glass is easily made brittle, and the annealing rate after molding needs to be increased, otherwise it is easy to burst.

The action of SrO and BaO is similar to that of CaO, which increases the refractive index of glass and modifies the optical constant of glass. The content of SrO is suitably from 0 to 10% by weight, preferably from 2 to 8%, particularly preferably from 3 to 6%. When the BaO content ratio is high, the ultraviolet absorption is shifted to the long-wave direction, and the BaO content is preferably from 1 to 10% by weight, preferably from 2 to 7%, particularly preferably from 3 to 5%.

Sr ²⁺ and Ba ²⁺ can effectively increase the refractive index of the glass to meet the higher refractive index of the light guide glass. However, as the radius of the alkaline earth metal ions increases, the ultraviolet cutoff wavelength shifts toward the long wavelength, which tends to increase the absorption of the violet region. Therefore, by virtue of the ternary or binary mixed alkali benefit, the optical performance can be optimally achieved, and the refractive index n _D and the transmittance ratios T ₄₀₀ /T ₅₅₀ and T ₄₅₀ /T _{550 are} ideal. In the alkaline earth metal content ratio, 0.9 ≤ (SrO + BaO) / CaO ≤ 1.5, preferably 1.1 ≤ (SrO + BaO) / CaO ≤ 1.2; 0.7 ≤ BaO / SrO ≤ 1.4, preferably 1.0 ≤ BaO / SrO ≤ 1.1, The Chinese chemical formula represents the mass percentage of the compound.

ZnO has a good fluxing effect at high temperature, can effectively reduce the high temperature viscosity of the light guide plate glass, but it is not an essential component. It can be used as an intermediate oxide. When free oxygen is sufficient, it can form a zinc oxide tetrahedron into the glass structure. The network stabilizes the glass structure, reduces the thermal expansion coefficient of the glass, and improves the thermal stability, chemical stability and refractive index of the glass. The content of ZnO is suitably from 0 to 10% by weight, preferably from 0 to 6%, particularly preferably from 0 to 4%. When the content of ZnO is high, the crystallization tendency of the glass is high, which tends to cause devitrification of the glass.

ZrO ₂ is an intermediate oxide which increases the viscosity, modulus of elasticity, refractive index, thermal stability, chemical stability and mechanical strength of the glass and is not an essential component. The content of ZrO ₂ is suitably from 0 to 5% by weight, preferably from 0 to 3%. When the content of ZrO _{2 is} high, the glass is difficult to melt, the melting temperature is increased, and the crystallization tendency of the glass is high, which tends to cause devitrification of the glass.

As a network external oxide, rare earth oxide can reduce the viscosity of glass, significantly increase the refractive index of glass, and modify the optical constant of glass. It is not an essential component and a small amount of La ₂ O ₃ can be introduced when a lower dispersion coefficient is required for some specific applications of the light guide. The content is suitably from 0 to 2% by weight, preferably from 0 to 1%. The high content of rare earth oxides tends to cause coloration of the glass and greatly increases the raw material cost of the glass.

As an impurity in the glass component, Fe ₂ O _{3 has} a great influence on the glass transmittance and color, and it is required to be strictly controlled. In order to obtain a good visible light transmittance, the content thereof is preferably 0.001% to 0.01%, preferably ≤80 ppm, particularly preferably ≤50 ppm.

The visible light transmittance of the mainstream ultra-white glass is generally greater than 91.5%. The main feature is that the Fe ₂ O ₃ content is controlled within 120 ppm, and the high-quality ultra-white glass can be controlled within 100 ppm. In the field of light guide plates, although ultra-white glass is superior to PMMA material in mechanical strength, thermal stability, weather resistance and chemical stability, the overall optical performance is slightly lower than PMMA, due to compositional uniformity and a certain amount of Fe ₂ O ₃ makes it have a large dispersion of light, and it is easy to make the color shift and color uniformity of the light-emitting surface of the backlight module poor.

For the light guide plate, the transmittance in the range of visible light wavelengths of 380 to 780 nm is required to be as high as possible, and light absorption in any wave number range is not generated as much as possible, so that the backlights of different spectral characteristics can be matched. The optical grade PMMA has a poor transmittance in the violet region, and it also shows that the material is susceptible to aging and decay due to long-term exposure to violet light and ultraviolet light. In this issue, the glass material light guide plate has a unique advantage. However, glass raw materials such as silica sand, limestone, etc. are liable to introduce colored metal ions such as Fe, and the high content seriously affects the optical properties of the glass.

Iron exists in the form of Fe ²⁺ and Fe ³⁺ in the glass, and the color of the glass mainly depends on the equilibrium state of the two. Fe ²⁺ ion has broad absorption region from the visible region to the infrared portion of the spectrum in the visible region of the absorption capacity is about fold ³⁺ Fe 10, Fe 10 times the coloring ability is ^3+, but a small amount of Fe ³⁺ The glass also exhibits strong absorption in the ultraviolet region of the spectrum, which in turn affects the transmittance of the glass in the visible violet region.

On the other hand, after the introduction of R ⁺ and M ²⁺ ions in the glass, the silicate glass network structure is broken to form more non-bridged oxygen, and the electrons are easily excited from the non-bridged oxygen to generate absorption in the ultraviolet range, and the ultraviolet cutoff The wavelength increases, which in turn affects the absorption of the visible violet region. Under the premise of ensuring the melting quality of aluminosilicate glass, the content of alkali metal and alkaline earth metal is reduced as much as possible, and the benefit of mixed alkali can promote the absorption peak of Fe ³⁺ ion in the ultraviolet region to move in the low wave number direction, thereby controlling the glass. Absorption in the violet region.

Due to the inevitable presence of impurities such as Fe ₂ O ₃ in the mineral raw material during the preparation of the glass, it is particularly important in the selection of the mineral raw material. The main mineral raw materials for introducing impurities such as Fe ₂ O ₃ are quartz sand and limestone. Therefore, it is preferable that SiO ₂ in the light guide plate glass is introduced in the form of pickled ultra-white quartz sand during the preparation of the light guide plate glass, and pickling ultra-white stone. Fe ₂ O ₃ content in the sand is more suitably ≤ 30 ppm, preferably ≤ 20 ppm, further preferably ≤ 10 ppm; Ca in the aluminosilicate glass is introduced in the form of ultra-white limestone in the preparation of the aluminosilicate glass, ultra-white limestone The content of Fe ₂ O _{3 in the} medium is preferably ≤ 50 ppm, preferably ≤ 30 ppm.

As a network external oxide, rare earth oxide can reduce the viscosity of glass, significantly increase the refractive index of glass, and modify the optical constant of glass. It is not an essential component and a small amount of La ₂ O ₃ can be introduced when a lower dispersion coefficient is required for some special applications of light guide glass. The content is suitably from 0 to 2% by weight, preferably from 0 to 1%. The high content of rare earth oxides tends to cause coloration of the glass and greatly increases the raw material cost of the glass.

Preferably, the light guide plate glass does not contain Ti, the purpose is to avoid absorption of the purple light region, and only to avoid any absorption of the light guide plate glass to the near ultraviolet region to the violet region, T ₄₀₀ /T ₅₅₀ and T ₄₅₀ /T ₅₅₀ The higher the possible, the higher the optical reduction of the light guide glass to the white LED.

Preferably, the thickness of the light guide plate glass is 2.5 mm, the transmittance in the visible wave number is 380 nm to 780 nm is greater than 92%, the internal transmittance is greater than 99%, the refractive index n _{D is} greater than 1.49, and the transmittance is T ₄₀₀ /T. _{550 is} greater than 99% and T ₄₅₀ /T _{550 is} greater than 99.5%.

The light guide plate glass is aluminosilicate glass, and the aluminosilicate glass has high strength and good rigidity, and the elastic modulus is generally 20 times or more of the PMMA material. Under the same thickness, the rigidity of the glass light guide plate is PMMA guide. More than 20 times of the light plate can be used to eliminate the structural support when applied to the backlight module, simplifying the structure of the backlight module; the aluminosilicate glass has good thermal stability, weather resistance and chemical stability, in its normal working range and Under the environmental conditions, its thermal expansion and hygroscopic expansion are small, which will not affect the display effect and structural support. After the introduction of R ⁺ and M ²⁺ ions in the glass of the light guide plate, the glass structure of the light guide plate is broken to form more non- Bridge oxygen, electrons are easily excited from non-bridged oxygen, generating absorption in the ultraviolet range, increasing the ultraviolet cut-off wavelength, which in turn affects the absorption of the visible violet region, and under the premise of ensuring the melting quality of the light guide glass, the alkali metal and The content of alkaline earth metal, and the benefit of mixed alkali can promote the absorption peak of Fe ³⁺ ion in the ultraviolet region to move in the low wave number direction, thereby controlling the glass in the purple region. Absorption of the domain; the total amount of Fe ions is strictly controlled in the glass of the light guide plate, and the ratio of Fe ²⁺ ions is determined to be in an optimum range to obtain the optimum degree of reduction for the white LED.

The method for preparing the above light guide plate glass comprises the following steps:

In step S100, the corresponding raw materials are weighed and mixed according to the mass percentage of each oxide standard, and then melted to obtain a molten glass.

Preferably, the corresponding raw materials are weighed according to the mass percentage of each oxide, and then heated at 1350 ° C to 1400 ° C for at least 0.5 hours to continue the heating temperature of the glass melting temperature to obtain a glass liquid.

Preferably, the SiO ₂ in the light guide plate glass is introduced in the form of pickled ultra-white quartz sand during the preparation of the light guide plate glass, and the Fe ₂ O ₃ content in the pickled ultra-white quartz sand is more suitably ≤ 30 ppm, preferably ≤ 20 ppm, further Preferably, ≤10 ppm; Ca in the light guide plate glass is introduced in the form of ultra-white limestone in the preparation of the light guide plate glass, and the Fe ₂ O ₃ content in the ultra-white limestone is preferably ≤ 50 ppm, preferably ≤ 30 ppm.

The raw materials used for preparing the glass batch are: pickled ultra-white quartz sand, aluminum powder, borax, lithium carbonate, soda ash, potassium carbonate, ultra-white limestone, barium carbonate, barium carbonate, zinc oxide, zircon, sodium sulfate, oxidation. Hey. However, the type of raw material is not limited to this.

In step S200, the glass liquid is homogenized and clarified, cast and molded in a mold, and annealed to obtain a light guide plate glass.

Preferably, the glass solution is homogenized and clarified at 1570 ° C to 1620 ° C for at least 5 hours, cast in a mold, and annealed at 508 ° C to 600 ° C for at least 0.5 h.

The preparation method of the above light guide plate glass is simple in process.

The above light guide plate glass will be described in detail below in conjunction with specific embodiments.

Examples 1 to 7

The molar percentages of the components in the light guide plate glasses of Examples 1 to 7 are shown in Table 1.

Table 1

Note: In Table 1, the molar percentage of each component is calculated without taking into account the Fe ₂ O ₃ content.

In the preparation of the light guide plate glass of Examples 1 to 7, the raw materials are thoroughly mixed and uniformly heated to a temperature of 1350 ° C in a laboratory high temperature electric furnace, and the glass batch material is placed in a platinum crucible and placed in an electric furnace together, and the temperature is maintained at 1350 ° C for 0.5 h. The temperature was further raised to the glass melting temperature, and the glass solution was homogenized and clarified at 1620 ° C for more than 5 hours. Then, the molten glass was cast in a special molding die to form a prescribed shape, and annealed at 600 ° C for 0.5 h in a muffle furnace, and a sample usable for testing was prepared by cutting and polishing. Among them, the Fe ₂ O ₃ content was obtained by fluorescent X-ray analysis of the sample. As shown in Table 1, the iron content in the light guide glass of Examples 1-7 can be controlled within 100 PPM.

The same samples were prepared for the light guide plate glass of Example 1-7, the ordinary ultra-white glass of Comparative Example 1, and the PMMA of Comparative Example 2, and the test results are shown in Table 2.

Among them, the temperature of 10 ² dPa.s is determined by GB/T 10247-2008;

Coefficient of thermal expansion (CTE), transition temperature, refractive index, transmittance, internal transmittance, measured by colorless optical glass test method: GB/T 7962-2010.

Table 2

As can be seen from Table 2, the optical properties of the light guide plates of Examples 1 to 7 were significantly superior to those of Comparative Example 1 and Comparative Example 2, and the spectral reduction degree of the white light LED was very high.

The technical features of the above-described embodiments may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be considered as the scope of this manual.

The above-mentioned embodiments are merely illustrative of one or more embodiments of the present invention, and the description thereof is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims (10)

1. A light guide plate glass, characterized in that the light guide plate glass is expressed by mass percentage of the following oxide standard, and includes the following components:

   55% to 75% SiO ₂ , 1% to 10% Al ₂ O ₃ , 0 to 15% B ₂ O ₃ , 5% to 15% R ₂ O, 10% to 20% MO, 0% ～10% ZnO, 0% to 5% ZrO ₂ and 0 to 2% rare earth oxide;

   Wherein the R ₂ O is at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O, and the MO is selected from at least two of CaO, SrO, and BaO.
2. The light guide plate glass according to claim 1, wherein the mass percentage based on the oxide is further contained in an amount of 0.001% to 0.01% of Fe ₂ O ₃ .
3. The light guide plate glass according to claim 1, wherein said MO is a mixture of SrO and BaO, and 0.7 ≤ BaO / SrO ≤ 1.4, wherein the chemical formula represents a mass percentage of the compound.
4. The light guide plate glass according to claim 3, wherein said MO is a mixture of CaO, SrO and BaO, and 0.9 ≤ (SrO + BaO) / CaO ≤ 1.5, wherein the chemical formula represents a mass percentage of the compound content.
5. The light guide plate glass according to claim 1, wherein the light guide plate glass does not contain Ti.
6. The light guide plate glass according to claim 1, wherein the light guide plate glass has a thickness of 2.5 mm and a transmittance of more than 92% in a visible light wave number of 380 nm to 780 nm, and an internal transmittance of more than 99%. The refractive index n _{D is} greater than 1.49, the transmittance T ₄₀₀ /T _{550 is} greater than 99%, and T ₄₅₀ /T _{550 is} greater than 99.5%.
7. The light guide plate glass according to claim 1, wherein SiO ₂ in the light guide plate glass is introduced in the form of pickled ultra-white quartz sand during the preparation of the light guide plate glass.
8. The light guide plate glass according to claim 7, wherein the pickled ultra-white quartz sand has a Fe ₂ O ₃ content of ≤ 30 ppm.
9. The light guide plate glass according to claim 1, wherein the light guide plate glass Ca is introduced in the form of ultra-white limestone during the preparation of the light guide glass.
10. The light guide plate glass according to claim 9, wherein the ultra-white limestone has a Fe ₂ O ₃ content of ≤ 50 ppm.