WO2019198363A1 - Panneau de guidage de lumière - Google Patents

Panneau de guidage de lumière Download PDF

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Publication number
WO2019198363A1
WO2019198363A1 PCT/JP2019/007566 JP2019007566W WO2019198363A1 WO 2019198363 A1 WO2019198363 A1 WO 2019198363A1 JP 2019007566 W JP2019007566 W JP 2019007566W WO 2019198363 A1 WO2019198363 A1 WO 2019198363A1
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content
light
glass plate
glass
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PCT/JP2019/007566
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English (en)
Japanese (ja)
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昌宏 林
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日本電気硝子株式会社
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/02—Surface treatment of glass, not in the form of fibres or filaments, by coating with glass
    • C03C17/04—Surface treatment of glass, not in the form of fibres or filaments, by coating with glass by fritting glass powder
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction

Definitions

  • the present invention relates to a light guide plate, and more particularly to a light guide plate suitable for an edge light type surface light emitting device.
  • Liquid crystal display devices are used for liquid crystal televisions.
  • the liquid crystal display device includes a surface light emitting device and a liquid crystal panel arranged on the light emitting surface side of the surface light emitting device.
  • a surface light emitting device for example, a direct type and an edge light type are known.
  • the light source is disposed on the back surface opposite to the light emitting surface.
  • a point light source such as a light emitting diode is used as the light source, a large number of LED chips are required to compensate for the brightness, resulting in extremely large variations in luminance.
  • the edge light type surface light emitting device includes a light source such as an LED, a light guide plate, a reflection plate (or reflection film), and the like.
  • a light source is arrange
  • the light guide plate is arranged to propagate light from the light source to the inside by total reflection and to emit the light in a planar shape.
  • a resin plate such as an acrylic resin is used as the light guide plate, but recently, a low expansion glass plate is being used as the light guide plate (see Patent Documents 1 to 4).
  • the reflecting plate is disposed on the light emitting surface and the light reflecting surface opposite to the light emitting surface, and is disposed to reflect light passing through the light reflecting surface to emit light on a display surface such as a liquid crystal panel.
  • a diffusion plate may be disposed on the light exit surface side of the light guide plate.
  • FIG. 1 is a conceptual cross-sectional view showing an example of an edge light type surface light emitting device 1.
  • the edge light type surface light emitting device 1 includes a light source 2 such as an LED, a light guide plate 3, a reflection plate 4, and a diffusion plate 5.
  • a light source 2 such as an LED
  • a light guide plate 3 a reflection plate 4
  • a diffusion plate 5 Light from the light source 2 enters from the end face of the light guide plate 3 and propagates into the light guide plate 3.
  • the light that reaches the light reflecting surface 6 is reflected by the reflecting plate 4, travels toward the light emitting surface 7, and is diffused by the diffusion plate 5.
  • a display surface such as a liquid crystal panel disposed above the diffusion plate 5 can emit light uniformly.
  • a display device such as a liquid crystal display device can be narrowed (see Patent Documents 1 to 4).
  • the glass plate has a problem that it absorbs light in the visible region (wavelength 380 to 750 nm) and causes a decrease in luminance.
  • Fe 2 O 3 contained in the glass. Then, Fe 2 O 3 is an impurity unavoidably mixed from introducing feedstock. Therefore, it is not easy to remove Fe 2 O 3 from the glass composition.
  • the present invention has been made in view of the above circumstances, and its technical problem is to devise a light guide plate in which the luminance is hardly lowered in the visible region even when a glass plate is used.
  • the present inventor has found that a large amount of Fe 2 O 3 is contained as an impurity in the introduced raw materials of MgO and CaO, and among the alkali metal oxides and alkaline earth metal oxides, MgO and CaO The present inventors have found that the above technical problem can be solved by reducing the content ratio of, and propose as the present invention.
  • the light guide plate of the present invention is a light guide plate having at least a glass plate, and the glass plate has a glass composition of 55% by mass, SiO 2 55-80%, Al 2 O 3 0-15%, B 2 O 3 1-20%, Li 2 O + Na 2 O + K 2 O 1-20%, MgO + CaO + SrO + BaO 0.1-10%, SnO 2 0-0.5%, Sb 2 O 3 0-0.5%, Fe 2 O 3 is contained in an amount of 0 to 0.005% (50 mass ppm or less), and the mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) is less than 0.40.
  • Li 2 O + Na 2 O + K 2 O refers to the total amount of Li 2 O, Na 2 O and K 2 O.
  • MgO + CaO + SrO + BaO refers to the total amount of MgO, CaO, SrO and BaO.
  • (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) is a value obtained by dividing the total amount of MgO and CaO by the total amount of Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO and BaO. Point to.
  • the light guide plate of the present invention has at least a glass plate. If a glass plate is used for the light guide plate instead of the resin plate, the difference in dimensional change between the display panel and the light guide plate is reduced, so there is no need to provide a large gap in the frame portion of the liquid crystal display device. A display device such as a device can be narrowed.
  • the mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) of the glass plate is less than 0.40. This makes it difficult for Fe 2 O 3 impurities to be mixed, so that the luminance of the display device can be increased.
  • the content of Fe 2 O 3 of the glass plate is not higher than 50 mass ppm.
  • the optical path length of the glass plate is 200 mm, and the maximum transmittance in the visible range can be increased.
  • Fe 2 O 3 exists in the state of Fe 3+ or Fe 2+ in the glass.
  • Fe 3+ has an absorption peak in the vicinity of a wavelength of 380 nm, and lowers the transmittance in the ultraviolet region and the visible region on the short wavelength side.
  • Fe 2+ has an absorption peak in the vicinity of a wavelength of 1080 nm, and decreases the transmittance in the visible region on the long wavelength side. Therefore, when the content of Fe 2 O 3 increases, the maximum transmittance in the visible range is likely to decrease.
  • Fe 2 O 3 in the present invention includes divalent iron oxide and trivalent iron oxide, and the divalent iron oxide is handled in terms of Fe 2 O 3 . Similarly, other polyvalent oxides are handled on the basis of the indicated oxide.
  • the content of Cr 2 O 3 in the glass plate is 5 ppm by mass or less
  • the content of TiO 2 is 50 ppm by mass or less
  • the content of Pt is 5 ppm by mass or less
  • the content of Rh The amount is preferably 5 ppm by mass or less. In this way, the transmittance in the visible range can be increased.
  • the basicity of the glass plate is preferably 0.54 or less.
  • a dot pattern is formed on any surface of the glass plate (usually, the surface facing the light exit surface). This dot pattern is formed by irradiation with ultraviolet rays. Sometimes. However, when the glass plate is irradiated with ultraviolet rays, the glass plate is colored and the transmittance in the visible region is lowered. When the transmittance in the visible region is reduced, the amount of light is diminished when light from the light source enters from the end face and exits to the light exit surface. As a result, the luminance of the display device tends to decrease.
  • the glass plate when the basicity of the glass plate is increased, the number of non-crosslinked oxygen in the glass network is increased and the number of colored centers is increased. As a result, the glass plate is likely to be colored by ultraviolet irradiation, and the transmittance in the visible range is likely to be lowered. Therefore, in the light guide plate of the present invention, it is preferable to regulate the basicity of the glass plate to 0.54 or less. Thereby, even if it irradiates with an ultraviolet-ray, the transmittance
  • the “basicity” is an index indicating the electron donating property of oxygen atoms in the glass, and is an index for evaluating the average Lewis basicity of oxide ions in the glass. Specifically, it is a value calculated by the following mathematical formula 1.
  • ⁇ is basicity
  • c i is the proportion of oxygen brought in by compound i
  • Z i is the valence of the cation
  • r i is the number of cations expressed per oxygen
  • compound i ⁇ i is a parameter called basicity moderating power, which is determined by the electronegativity ⁇ i of the cation.
  • the amount of network forming oxide such as SiO 2 , Al 2 O 3 , B 2 O 3 is increased, and MgO, CaO, SrO, BaO, ZnO, Li 2 O, Na 2 O, it may be reduced to the content of the network modifier oxides of K 2 O or the like.
  • FIG. 2 shows the difference between the basicity and the average transmittance in the visible range before and after the ultraviolet irradiation (optical path length 2 mm, average transmittance in the wavelength range 400 to 750 nm, output 0.1 mW, wavelength 185 nm, output 13.
  • 3 is a graph showing the relationship between the optical path length of 2 mm and the average transmittance in the wavelength range of 400 to 750 nm after simultaneous irradiation with ultraviolet rays of 3 mW, wavelength of 254 nm, and 0.4 mW and wavelength of 365 nm for 12 hours.
  • FIG. 2 when the basicity is lowered, the average transmittance difference in the visible region before and after the ultraviolet irradiation is reduced.
  • the light guide plate of the present invention has a glass plate with an optical path length of 200 mm and a maximum transmittance of 85% or more in the wavelength range of 400 to 750 nm, and a glass plate with an optical path length of 200 mm and a minimum transmittance of 80 to 80 in the wavelength range of 400 to 750 nm. % Or more, and the difference between the maximum transmittance and the minimum transmittance is preferably 10% or less.
  • the “transmittance” can be measured by a commercially available transmittance measuring device, for example, can be measured by UV-3100PC manufactured by Shimadzu Corporation, and unless otherwise specified, is calculated by the formula 2. It refers to transmittance.
  • a dot pattern is formed on at least one surface of the glass plate.
  • the light guide plate of the present invention is preferably used for an edge light type surface light emitting device.
  • FIG. 3 is a conceptual perspective view showing an example of the light guide plate of the present invention.
  • the light guide plate 10 includes a glass plate 11.
  • the light from the light source 12 enters from the end surface 13 of the glass plate 11, propagates through the inside of the glass plate 11, and exits from the light exit surface.
  • a dot pattern 15 is formed on the light reflecting surface 14 of the glass plate 11.
  • the dot diameter of the dot pattern 15 gradually increases from the end surface 13 toward the end surface 16.
  • the light emitted from the light emitting surface is made uniform in the surface.
  • a reflection layer 19 is formed on each of the end faces 16, 17, and 18 of the glass plate. And the light which reached
  • a large-area light guide plate can be manufactured by joining the end faces that are not bonded with a transparent adhesive having a matched refractive index.
  • the glass plate has a glass composition of SiO 2 55 to 80%, Al 2 O 3 0 to 15%, B 2 O 3 1 to 20%, Li 2 O + Na 2 O + K 2 in terms of glass composition.
  • the mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) is less than 0.40.
  • % display means the mass%.
  • SiO 2 is a component that serves as a network former of glass, and is a component that reduces a thermal expansion coefficient and reduces a dimensional change due to heat. It is a component that increases acid resistance and strain point.
  • the content of SiO 2 is 55 to 80%, preferably 58 to 78%, 60 to 75%, 62 to 74%, particularly 64 to 72%.
  • the content of SiO 2 decreases, the basicity tends to increase, the thermal expansion coefficient increases, and the dimensional change due to heat tends to increase. In addition, acid resistance and strain point are likely to be lowered.
  • the content of SiO 2 is increased, the high temperature viscosity is increased, the meltability is lowered, and the devitrification of cristobalite is likely to precipitate during molding.
  • Al 2 O 3 is a component that lowers the thermal expansion coefficient and reduces dimensional changes due to heat. It also has the effect of increasing the strain point and suppressing the precipitation of devitrified cristobalite during molding.
  • the content of Al 2 O 3 is 0 to 15%, preferably 0.1 to 13%, 1 to 12%, particularly 4 to 11%.
  • the content of Al 2 O 3 decreases, the basicity tends to increase, the coefficient of thermal expansion increases, and the dimensional change due to heat tends to increase.
  • the strain point tends to decrease.
  • the content of Al 2 O 3 increases, the liquidus temperature rises and it becomes difficult to form a glass plate.
  • B 2 O 3 is a component that acts as a flux, lowers the high temperature viscosity, and improves the meltability. Moreover, it is a component which reduces a thermal expansion coefficient and reduces the dimensional change by a heat
  • the content of B 2 O 3 is 1 to 20%, preferably 5 to 18%, 7 to 17%, 9 to 16%, particularly 10 to 15%.
  • the content of B 2 O 3 is reduced, the basicity is likely to increase, the high temperature viscosity is increased, and the meltability is likely to be lowered. In addition, devitrification grains such as cristobalite are likely to precipitate.
  • the content of B 2 O 3 is increased, the strain point and acid resistance are likely to be lowered. Moreover, it becomes easy to phase-separate glass.
  • the content of SiO 2 + Al 2 O 3 + B 2 O 3 is preferably 83% or more, 85% or more, 86% or more, 88% or more, particularly 90 to 93%.
  • the content of SiO 2 + Al 2 O 3 + B 2 O 3 decreases, the basicity tends to increase.
  • SiO 2 + Al 2 O 3 + B 2 O 3 refers to the total amount of SiO 2 , Al 2 O 3 and B 2 O 3 .
  • the content of Li 2 O + Na 2 O + K 2 O is 1 to 20%, preferably 2 to 15%, 3 to 13%, 4 to 12%, particularly 5 to 11%.
  • the Li 2 O content is preferably 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.5%, particularly 0 to 0.1%.
  • the content of Na 2 O is preferably 0 to 13%, 2 to 10%, 3 to 9%, 4 to 8%, particularly 5 to 7%.
  • the content of K 2 O is preferably 0 to 9%, 0 to 7%, 0 to 5%, 0 to 4%, particularly 0.1 to 3%.
  • the content of MgO + CaO + SrO + BaO is 0.1 to 10%, preferably 0.3 to 8%, particularly 0.5 to 5%.
  • the content of MgO + CaO + SrO + BaO decreases, the high-temperature viscosity increases and the meltability tends to decrease.
  • the content of MgO + CaO + SrO + BaO increases, Fe 2 O 3 impurities are easily mixed from the introduced raw material. In addition, the basicity tends to increase.
  • the mass ratio (SiO 2 + Al 2 O 3 + B 2 O 3 ) / (MgO + CaO + SrO + BaO) is preferably 15 or more, particularly 20 or more. If the mass ratio (SiO 2 + Al 2 O 3 + B 2 O 3 ) / (MgO + CaO + SrO + BaO) is too small, the basicity tends to increase.
  • the mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) is less than 0.40, 0.35 or less, 0.32 or less, 0.30 or less, 0.28 or less, 0.26 or less, 0. 24 or less, 0.22 or less, 0.20 or less, 0.18 or less, 0.16 or less, 0.14 or less, 0.12 or less, 0.10 or less, 0.08 or less, 0.06 or less, especially 0 .04 or less.
  • the mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) increases, Fe 2 O 3 impurities are easily mixed from the introduced raw material.
  • MgO is a component that lowers the viscosity at high temperature and improves the meltability, but is a component that lowers the luminance of the display device from Fe 2 O 3 impurities in the introduced raw material.
  • the content of MgO is preferably 0-5%, 0-4%, 0.2-3%, especially 0.5-2%.
  • the content of MgO decreases, the high-temperature viscosity increases and the meltability tends to decrease.
  • Fe 2 O 3 impurities are easily mixed from the introduced raw material and the basicity is easily increased. In addition, devitrification is likely to precipitate during molding.
  • CaO is a component that reduces only the high-temperature viscosity without reducing the strain point and improves the meltability.
  • CaO is a component that lowers the luminance of the display device from Fe 2 O 3 impurities in the introduced raw material.
  • the CaO content is preferably 0-10%, 0.1-8%, 0.2-7%, 0.3-6%, 0.4-5%, especially 0.5-4%. .
  • the content of CaO decreases, the high-temperature viscosity increases and the meltability tends to decrease.
  • Fe 2 O 3 impurities are easily mixed from the introduced raw material, and the basicity is easily increased. In addition, devitrification is likely to precipitate during molding.
  • SrO is a component that lowers the viscosity at high temperature, improves the meltability, and increases the chemical resistance and devitrification resistance.
  • the content of SrO is preferably 0 to 10%, 0.1 to 8%, 0.2 to 7%, 0.3 to 6%, 0.4 to 5%, especially 0.5 to 4%. .
  • the content of SrO decreases, the high-temperature viscosity increases and the meltability tends to decrease.
  • the content of SrO increases, the density and basicity tend to increase, the thermal expansion coefficient increases, and the dimensional change due to heat tends to increase.
  • BaO is a component that lowers the viscosity at high temperature, improves meltability, and increases chemical resistance and devitrification resistance.
  • the content of BaO is preferably 0 to 10%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5%, especially 0.1 to 4%.
  • the content of BaO decreases, the high-temperature viscosity increases and the meltability tends to decrease.
  • the content of BaO increases, the density and basicity tend to increase, the thermal expansion coefficient increases, and the dimensional change due to heat tends to increase.
  • SnO 2 and Sb 2 O 3 are components that act as fining agents.
  • the content of SnO 2 is 0 to 0.5%, preferably 0.01 to 0.5%, 0.05 to 0.5%, 0.07 to 0.5%, particularly 0.1 to 0. 4%.
  • the content of Sb 2 O 3 is 0 to 0.5%, preferably 0.01 to 0.5%, 0.05 to 0.5%, 0.07 to 0.5%, especially 0.1 ⁇ 0.4%.
  • Fe 2 O 3 is a component that absorbs light and is a component that lowers the transmittance in the visible range.
  • the content of Fe 2 O 3 is 0 to 0.005% (50 mass ppm or less), preferably 40 mass ppm or less, 30 mass ppm or less, 25 mass ppm or less, 20 mass ppm or less, particularly 4 to 25 mass. ppm.
  • the content of Fe 2 O 3 increases, the luminance of the display device tends to decrease. In the case Fe 2 O is excessively low content of 3, the raw material cost, the cost of manufacturing the glass sheet to rise.
  • the content of Cr 2 O 3 is preferably less than 10 ppm, 8 ppm or less, 6 ppm or less, 0.1 to 5 ppm, 0.2 to 4 ppm, especially 0.3 to 3 ppm. It is. When the content of Cr 2 O 3 increases, the transmittance in the visible range is likely to decrease. In the case Cr 2 O is excessively low content of 3, the raw material cost, the cost of manufacturing the glass sheet to rise.
  • TiO 2 is a component that absorbs light and is a component that lowers the transmittance in the visible range.
  • the content of TiO 2 is preferably 50 mass ppm or less, 30 mass ppm or less, 20 mass ppm or less, 15 mass ppm or less, 10 mass ppm or less, particularly 1 to 5 mass ppm.
  • the content of TiO 2 increases, the luminance of the display device tends to decrease.
  • the content of TiO 2 is excessively small, the raw material cost, the cost of manufacturing the glass sheet to rise.
  • the raw material preparation equipment etc. can be fed to the raw material Fe 2 O 3 , Cr It is effective to use a production facility designed so that colored oxides such as 2 O 3 and TiO 2 are not mixed.
  • the content of Pt is preferably 5 mass ppm or less, 3 mass ppm or less, 2 mass ppm or less, 0.01 to 1 mass ppm, particularly 0.05 to 0.8 mass ppm.
  • the content of Pt increases, the transmittance in the visible range tends to decrease.
  • strength Pt for glass manufacturing equipment, and the manufacturing cost of a glass plate will rise.
  • Rh is preferably 5 mass ppm or less, 3 mass ppm or less, 2 mass ppm or less, 0.01 to 1 mass ppm, 0.05 to 0.8 mass ppm, particularly 0.1 to 0.7 mass ppm.
  • the content of Rh increases, the difference in transmittance between the maximum transmittance and the minimum transmittance in the visible range tends to be excessive. If the Rh content is excessively small, it becomes difficult to use a high-strength Pt—Rh alloy in the glass production facility, and the production cost of the glass plate increases.
  • In order to reduce the Rh content as much as possible use high-purity glass raw materials, adjust the glass manufacturing conditions so that Rh does not enter, or use the Pt-Rh alloy in the glass manufacturing facility. You can reduce it.
  • Y 2 O 3 , Nb 2 O 5 , P 2 O 5 are each up to 3%, and to lower the melting temperature, Cs 2 O is up to 5% each, and a fining agent Alternatively, SO 3 , F, Cl, etc. may be introduced up to 0.5% in total.
  • 2 O 3 is an environmentally hazardous substance, and when a glass plate is formed by the float process, it is preferably reduced in a float bath to become a metal foreign material. The content is preferably 0.5% or less and less than 0.01%, respectively.
  • the water content is preferably 500 ppm or less, 400 ppm or less, 300 ppm or less, particularly 250 ppm or less.
  • the “water content” can be calculated by multiplying the ⁇ -OH value (/ mm) by a coefficient specific to the glass composition.
  • the ⁇ -OH value can be calculated by Equation 3.
  • ⁇ -OH value (1 / X) log (T 1 / T 2 )
  • X wall thickness
  • T 1 transmittance at a reference wave number of 3846 cm ⁇ 1
  • T 2 minimum transmittance near the OH group absorption wave number of 3600 cm ⁇ 1
  • the light guide plate of the present invention includes at least a glass plate, and the glass plate preferably has the following characteristics.
  • the basicity is preferably 0.54 or less, 0.53 or less, 0.52 or less, 0.51 or less, 0.50 or less, 0.49 or less, particularly 0.30 to 0.48. If the basicity is too high, the transmittance tends to decrease due to the irradiation of ultraviolet rays, and the luminance of the display device is likely to decrease.
  • the maximum transmittance in an optical path length of 200 mm and a wavelength range of 400 to 750 nm is preferably 85% or more, 86% or more, 87% or more, particularly 88% or more. If the maximum transmittance in the optical path length of 200 mm and the wavelength range of 400 to 750 nm is too low, the luminance of the display device tends to be lowered.
  • the minimum transmittance in an optical path length of 200 mm and a wavelength range of 400 to 750 nm is preferably 75% or more, 82% or more, 84% or more, and particularly 85% or more. If the minimum transmittance in the optical path length of 200 mm and the wavelength range of 400 to 750 nm is too low, the luminance of the display device tends to be lowered.
  • the difference between the maximum transmittance and the minimum transmittance in an optical path length of 200 mm and a wavelength range of 400 to 750 nm is preferably 10% or less, 7% or less, 5% or less, 3% or less, 2% or less, particularly 1% or less.
  • the difference between the maximum transmittance and the minimum transmittance in an optical path length of 200 mm and a wavelength range of 400 to 750 nm increases, the luminance of the display device tends to decrease.
  • the glass plate has an optical path length of 2 mm, an average transmittance X (%) in a wavelength range of 400 to 750 nm, an output of 0.1 mW, an ultraviolet ray of a wavelength of 185 nm, an output of 13.3 mW, an ultraviolet ray of a wavelength of 254 nm, and
  • Y (%) When the average transmittance in an optical path length of 2 mm and a wavelength range of 400 to 750 nm after irradiation with ultraviolet rays of 0.4 mW and wavelength of 365 nm simultaneously for 12 hours is Y (%), the relationship of XY ⁇ 1% is satisfied.
  • XY is less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, particularly less than 0.4%. If the average transmittance difference before and after the ultraviolet irradiation is too large, it is difficult to ensure the brightness of the display device.
  • the thermal expansion coefficient in the temperature range of 30 to 380 ° C. is preferably 120 ⁇ 10 ⁇ 7 / ° C. or less, 95 ⁇ 10 ⁇ 7 / ° C. or less, 75 ⁇ 10 ⁇ 7 / ° C. or less, particularly 30 ⁇ 10 ⁇ 7 to 70 ⁇ 10 ⁇ 7 / ° C. If the thermal expansion coefficient of the glass plate is too high, the difference in dimensional change due to heat between the display panel and the light guide plate becomes large.
  • “thermal expansion coefficient in the temperature range of 30 to 380 ° C.” is an average value measured with a dilatometer in accordance with JIS R3102.
  • the strain point is preferably 400 ° C or higher, 420 ° C or higher, 440 ° C or higher, 460 ° C or higher, 470 ° C or higher, 480 ° C or higher, particularly 490 ° C or higher. If the strain point is too low, the heat resistance tends to decrease. For example, when a reflective film or the like is formed on the surface of the glass plate at a high temperature, the glass plate is likely to be thermally deformed.
  • the “strain point” is a value measured based on JIS R3103.
  • the liquidus temperature is preferably 1000 ° C. or lower, particularly 970 ° C. or lower.
  • the liquid phase viscosity is preferably 10 4.6 dPa ⁇ s or more, particularly 10 5.0 dPa ⁇ s or more.
  • the “liquid phase temperature” is set to 1100 ° C. to 1350 ° C. by crushing each sample, passing the standard sieve 30 mesh (500 ⁇ m), and putting the glass powder remaining on 50 mesh (300 ⁇ m) into a platinum boat. After being held in a temperature gradient furnace for 24 hours, the platinum boat was taken out and the glass was devitrified (foreign crystal foreign matter).
  • “Liquid phase viscosity” is a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method.
  • the dimension of at least one side of the glass plate is preferably 1000 mm or more, 1500 mm or more, 2000 mm or more, 2500 mm or more, particularly 3000 mm or more. In this way, it is possible to satisfy the demand for an increase in the size of the display device.
  • the glass plate is preferably formed by an overflow downdraw method.
  • an overflow downdraw method it is difficult to produce a temperature difference and composition difference between the front and back surfaces of the glass ribbon during molding, and it becomes easy to form a glass plate that is unpolished and has good surface quality.
  • the manufacturing cost of the light guide plate is low.
  • uniform brightness the reason for this is that, in the case of the overflow downdraw method, the surface to be the surface does not come into contact with the bowl-like refractory and is molded in a free surface state.
  • the structure and material of the bowl-shaped structure are not particularly limited as long as desired dimensions and surface quality can be realized.
  • the method of applying force with respect to a glass ribbon will not be specifically limited if a desired dimension and surface quality are realizable.
  • a method may be adopted in which a heat-resistant roll having a sufficiently large width is rotated and stretched in contact with the glass ribbon, or a plurality of pairs of heat-resistant rolls are only near the end face of the glass ribbon. You may employ
  • the glass plate can be formed by a slot downdraw method, a float method, a rollout method, a redraw method, or the like.
  • a temperature difference and a composition difference between the front and back surfaces of the glass ribbon are likely to occur during molding.
  • the temperature difference and the composition difference can be reduced.
  • the light guide plate of the present invention preferably has a dot pattern formed on at least one surface (preferably the light exit surface) of the glass plate.
  • a dot pattern is formed on the surface of the glass plate, air with a low refractive index can be brought into contact between the dots constituting the dot pattern. Thereby, total reflection conditions are satisfy
  • the diameter of the dots constituting the dot pattern is gradually increased as the distance from the end face to which light from the light source is incident. If it does in this way, it will become easy to equalize the light radiate
  • the dot pattern can be formed, for example, by printing and baking a heat-resistant paint or glass frit on the surface of the glass plate.
  • the shape of the dots constituting the dot pattern is not particularly limited, and examples thereof include a circle, an ellipse, a rectangle, a triangle, and a polygon. Among them, the dot shape is preferably circular.
  • the average surface roughness Ra of the end face of the glass plate is preferably 0.5 ⁇ m or less, 0.3 ⁇ m or less, 0.2 ⁇ m or less, particularly 0.1 ⁇ m or less. This makes it easy to reduce the loss of light when light from the light source enters the end face. Moreover, it becomes easy to form a high-quality reflective layer on the end face.
  • the average surface roughness Ra of the end surface of the glass plate can be reduced as much as possible.
  • the average surface roughness Ra of the end surface of the glass plate can be reduced without causing polishing scratches.
  • the end face of the glass plate preferably has no chamfered portion. If it does in this way, it will become easy to take in the light from a light source to the inside of a glass plate.
  • a reflection layer is preferably formed on all or a part of the end surface other than the end surface on which light from the light source is incident, and all of the end surfaces other than the end surface on which light from the light source is incident. It is particularly preferable that a reflective layer is formed on the surface. If it does in this way, the light which propagated inside the glass plate will become difficult to leak from an end face. Note that, as the reflective layer, a reflective film may be directly formed on the end face, but a reflective seal may be attached to the end face.
  • the light guide plate of the present invention preferably includes a diffusion plate on one surface (preferably the light exit surface) side of the glass plate, and reflects on one surface (preferably the surface facing the light exit surface) side of the glass plate. It is preferable to provide a plate. In this way, it becomes easy to make the luminance of the display device uniform.
  • Tables 1 to 10 show examples of the present invention (sample Nos. 1 to 193).
  • R 2 O indicates Li 2 O + Na 2 O + K 2 O
  • RO indicates MgO + CaO + SrO + BaO.
  • cri in the first phase indicates cristobalite, and “Quartz” indicates quartz.
  • a glass batch in which glass raw materials were prepared so as to have the glass composition shown in the table was placed in a platinum crucible and then melted at 1200 to 1650 ° C. for 24 hours. In melting the glass batch, the mixture was stirred and homogenized using a platinum stirrer. Next, the molten glass was poured onto a carbon plate and formed into a plate shape, and then slowly cooled at a temperature near the annealing point for 30 minutes.
  • the water content H 2 O is calculated by multiplying the ⁇ -OH value (/ mm) by a coefficient 0.09 specific to the glass composition.
  • the ⁇ -OH value can be calculated by Equation 3 above.
  • the maximum transmittance and the minimum transmittance in an optical path length of 200 mm and a wavelength range of 400 to 750 nm are calculated by the above formula 2, and are measured by UV-3100PC manufactured by Shimadzu Corporation.
  • the thermal expansion coefficient ⁇ in the temperature range of 30 to 380 ° C. is an average value measured with a dilatometer in accordance with JIS R3102.
  • the density ⁇ is a value measured by the well-known Archimedes method.
  • strain point Ps, annealing point Ta, and softening point Ts are values measured based on the methods of ASTM C336 and C338.
  • High temperature viscosity 10 4.0, 10 3.0, temperature at 10 2.5 dPa ⁇ s is a value measured by a platinum ball pulling method.
  • the liquid phase temperature TL is a temperature gradient set between 1100 ° C. and 1350 ° C. by crushing each sample, passing through a standard sieve 30 mesh (500 ⁇ m), and putting the glass powder remaining on 50 mesh (300 ⁇ m) into a platinum boat. After being kept in the furnace for 24 hours, the platinum boat was taken out, and the temperature at which devitrification (crystal foreign matter) was observed in the glass. Then, crystals precipitated in the temperature range from the liquid phase temperature TL (liquid phase temperature TL-50 ° C.) were observed with an electron microscope and evaluated as the initial phase. Furthermore, the viscosity of the glass at the liquidus temperature was measured by the platinum ball pulling method, and this was defined as the liquidus viscosity log ⁇ at TL.
  • sample no. 1 to 193 had a low mass ratio (MgO + CaO) / (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO) and a low content of Fe 2 O 3 , and thus the transmittance in the visible region was high. Therefore, sample no. Nos. 1 to 193 are considered to be suitable as light guide plates used in edge light type surface light emitting devices.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Glass Compositions (AREA)
  • Planar Illumination Modules (AREA)
  • Surface Treatment Of Glass (AREA)

Abstract

La présente invention concerne un panneau de guidage de lumière pourvu d'au moins une plaque en verre, et caractérisé en ce que la plaque en verre a une composition de verre contenant, en % massiques, 55 à 80 % de SiO2, 0 à 15 % d'Al2O3, 1 à 20 % de B2O3, 1 à 20 % de Li2O + Na2O + K2O, 0,1 à 10 % de MgO + CaO + SrO + BaO, 0 à 0,5 % de SnO2, 0 à 0,5 % de Sb2O3 et 0 à 0,005 % (50 ppm massiques ou moins) de Fe2O3, le rapport massique (MgO+CaO)/(Li2O+Na2O+K2O+MgO+CaO+SrO+BaO) étant inférieur à 0,40.
PCT/JP2019/007566 2018-04-09 2019-02-27 Panneau de guidage de lumière WO2019198363A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11951713B2 (en) 2020-12-10 2024-04-09 Corning Incorporated Glass with unique fracture behavior for vehicle windshield
US12122714B2 (en) 2022-09-30 2024-10-22 Corning Incorporated Glass with unique fracture behavior for vehicle windshield

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116615347A (zh) * 2020-12-18 2023-08-18 Ａｇｃ株式会社 硼硅酸盐玻璃、夹层玻璃和车辆用窗玻璃

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* Cited by examiner, † Cited by third party
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JP2007126298A (ja) * 2005-10-31 2007-05-24 Ohara Inc 光学ガラス
JP2011225418A (ja) * 2010-03-30 2011-11-10 Nippon Electric Glass Co Ltd 光学ガラス
WO2016031345A1 (fr) * 2014-08-28 2016-03-03 旭硝子株式会社 Plaque de verre
JP2017043530A (ja) * 2015-06-24 2017-03-02 日本電気硝子株式会社 導光板
JP2017052687A (ja) * 2015-08-17 2017-03-16 ショット アクチエンゲゼルシャフトＳｃｈｏｔｔ ＡＧ 導光板、及びバックライトを有する光学ディスプレイ
WO2018159385A1 (fr) * 2017-02-28 2018-09-07 日本電気硝子株式会社 Plaque de guidage de lumière

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007126298A (ja) * 2005-10-31 2007-05-24 Ohara Inc 光学ガラス
JP2011225418A (ja) * 2010-03-30 2011-11-10 Nippon Electric Glass Co Ltd 光学ガラス
WO2016031345A1 (fr) * 2014-08-28 2016-03-03 旭硝子株式会社 Plaque de verre
JP2017043530A (ja) * 2015-06-24 2017-03-02 日本電気硝子株式会社 導光板
JP2017052687A (ja) * 2015-08-17 2017-03-16 ショット アクチエンゲゼルシャフトＳｃｈｏｔｔ ＡＧ 導光板、及びバックライトを有する光学ディスプレイ
WO2018159385A1 (fr) * 2017-02-28 2018-09-07 日本電気硝子株式会社 Plaque de guidage de lumière

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11951713B2 (en) 2020-12-10 2024-04-09 Corning Incorporated Glass with unique fracture behavior for vehicle windshield
US12122714B2 (en) 2022-09-30 2024-10-22 Corning Incorporated Glass with unique fracture behavior for vehicle windshield

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