WO2016031830A1 - Glass sheet - Google Patents

Glass sheet Download PDF

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Publication number
WO2016031830A1
WO2016031830A1 PCT/JP2015/073905 JP2015073905W WO2016031830A1 WO 2016031830 A1 WO2016031830 A1 WO 2016031830A1 JP 2015073905 W JP2015073905 W JP 2015073905W WO 2016031830 A1 WO2016031830 A1 WO 2016031830A1
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WIPO (PCT)
Prior art keywords
light
glass
less
main surface
glass plate
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PCT/JP2015/073905
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French (fr)
Japanese (ja)
Inventor
鈴木　克巳
和矢 竹本
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旭硝子株式会社
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Publication of WO2016031830A1 publication Critical patent/WO2016031830A1/en

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    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings

Definitions

  • the present invention relates to a glass plate suitably used as a light guide plate of an edge light type planar light emitting device.
  • liquid crystal display devices have been used for mobile phones, PDAs, liquid crystal televisions, and the like.
  • the liquid crystal display device has a basic configuration of a planar light emitting device as a backlight and a liquid crystal unit disposed on the light emitting surface side of the planar light emitting device.
  • the planar light emitting device there are a direct type and an edge light type.
  • the direct type the light source is arranged on the back surface opposite to the light emitting surface, and therefore a light source having the same size as the light emitting surface is required.
  • the edge light type is suitable for increasing the screen of a liquid crystal display device because a light source is disposed on a side surface that is orthogonal to the light emitting surface, so that a light source having a smaller size than the light emitting surface can be used.
  • planar light emitting device also has a demand as a planar lighting device disposed indoors or outdoors such as a ceiling, floor or wall of a building.
  • Reflecting member 300 for returning light emitted from the light reflecting surface (lower surface in the figure) opposite to the light emitting surface (upper surface in the figure) that emits light to the light guide plate 200, and its interior
  • the brightness is uneven on the light exit surface when the light source is a point light source, and the brightness unevenness on the light exit surface due to the difference in distance from the light source It is comprised by the scattering member 400 which suppresses etc.
  • the reflection member 300 is a plate-like member arranged so that its main surface faces the light reflection surface of the light guide plate 200.
  • the scattering member 400 is formed on the light reflection surface of the light guide plate 200 at a predetermined interval in a dot pattern so as to be positioned between the light guide plate 200 and the reflection member 300.
  • the light guide plate 200 of the light guide plate unit 100 is conventionally made of a transparent resin material such as an acrylic resin or a polycarbonate resin because of its high transmittance, relatively low cost and easy availability. (See Patent Document 1).
  • the planar light emitting device In order to cope with an increase in the screen size of the liquid crystal display device, when the planar light emitting device is enlarged, a light source with higher output is used. As a result, the amount of heat generated by the light source increases and the light guide plate is also required to have heat resistance.
  • the above light guide plate made of a resin material has insufficient heat resistance because the glass transition point (Tg) is as low as 80 to 100 ° C. (acrylic resin) and 145 to 150 ° C. (polycarbonate resin).
  • the bubbles present inside the light guide plate made of a resin material are effective in improving front luminance and uniform luminance by acting as an optical path changing element if the pore diameter and porosity are appropriate.
  • the bubbles present inside the light guide plate made of a resin material are usually spherical.
  • the size of bubbles present in the molten glass is various, and as described above, measures are taken to reduce the amount of bubbles present in the glass plate during the production of the glass plate. Therefore, it is preferable that bubbles existing inside the glass plate used as the light guide plate do not affect the optical characteristics of the light guide plate, rather than expecting an action as an optical path changing element.
  • the present invention is a glass having high transparency in the visible light region and high luminance uniformity when used as a light guide plate of an edge light type planar light emitting device.
  • the purpose is to provide a board.
  • the maximum value ⁇ max of the light absorption coefficient in the wavelength range of 400 to 700 nm is preferably 1 m ⁇ 1 or less, more preferably 0.5 m ⁇ 1 or less, and even more preferably 0. .2m -1 or less.
  • ⁇ max is 1 m ⁇ 1 or less, the front luminance can be improved when used as a light guide plate.
  • the first main surface and the second main surface are substantially rectangular, the length of at least one side is 200 mm or more, and the thickness of the glass plate is 0.5 to 10 mm.
  • the thickness tolerance of the glass is preferably within ⁇ 0.1 mm.
  • the glass plate of the present invention preferably has an average luminance L ave of 1000 cd / m 2 or more in the light emitted from the second main surface.
  • the glass plate of the present invention has high transparency in the visible light region and high uniformity of brightness when used as a light guide plate of an edge light type planar light emitting device. It is suitable as a light guide plate.
  • FIG. 3 is a perspective view showing one structural example of the glass plate of the present invention.
  • the glass plate 10 shown in FIG. 3 includes a first main surface 11, a second main surface 12 facing the first main surface 11, and an end face 13 connecting the first main surface 11 and the second main surface 12.
  • the first main surface 11 and the second main surface 12 are substantially rectangular.
  • the shapes of the first main surface and the second main surface are not substantially limited to rectangles, and may be other shapes.
  • the first main surface 11 and the second main surface 12 in the glass plate of the present invention specify the two main surfaces of the glass plate for convenience in order to specify the side on which the reflecting member and the scattering member are arranged at the time of luminance measurement.
  • the first main surface 11 and the second main surface 12 are defined. Therefore, either surface of the two main surfaces of the glass plate may be the first main surface (second main surface).
  • the first main surface 11 and the second main surface 12 have a rectangular shape, but the first main surface 11 and the second main surface 12 may have a square shape. Good. Further, a notch may be provided for fixing in the case frame.
  • the length of one side of the main surface (first main surface 11 and second main surface 12) of the glass plate is a planar light emission using the glass plate of the present invention as a light guide plate. It depends on the dimensions of the device.
  • the length of one side of the main surface (first main surface 11 and second main surface 12) of the glass plate is preferably 200 mm or more, and 250 mm. More preferably, it is more preferably 400 nm or more.
  • the thickness of the glass plate (the thickness of the end face 13) is preferably 0.5 to 10 mm.
  • the internal transmittance of the glass plate used as the light guide plate is affected by the thickness of the glass member.
  • the thickness of the glass plate is 0.5 mm or more
  • the number of reflections on the glass surface is prevented from increasing, the attenuation due to reflection increases, and the internal transmittance at the effective optical path length is increased. It can be prevented from lowering. More preferably, it is 1 mm or more, More preferably, it is 1.5 mm or more.
  • the thickness tolerance of the glass plate is preferably within ⁇ 0.1 mm, more preferably within ⁇ 0.08 mm, and even more preferably within ⁇ 0.05 mm.
  • the tolerance of the thickness of the glass plate is within ⁇ 0.1 mm, it is possible to stabilize the light incident from the light source to the glass plate and improve the in-plane luminance uniformity. .
  • the glass plate 10 of the present invention is used as a light guide plate of an edge light type planar light emitting device, it is preferable that the light absorption coefficient is low in the wavelength range of the light source of the planar light emitting device.
  • a light-emitting diode (LED) is used as a light source, specifically, R (red), G (green) and B (blue) LEDs are used. Is done. Therefore, it is preferable that the absorption coefficient of light of these three colors is low.
  • the glass plate 10 of the present invention has a light absorption coefficient of 1 m ⁇ 1 or less at a wavelength of 550 nm, a maximum value ⁇ max (m ⁇ 1 ) of a light absorption coefficient in a wavelength range of 400 to 700 nm, and a minimum value ⁇ min.
  • the ratio ( ⁇ max / ⁇ min ) to (m ⁇ 1 ) is 10 or less.
  • the absorption coefficient of light having a wavelength of 550 nm is preferably 0.5 m ⁇ 1 or less, more preferably 0.2 m ⁇ 1 or less, and even more preferably 0.1 m ⁇ 1 or less.
  • the ( ⁇ max / ⁇ min ) is preferably 7 or less, more preferably 5 or less, and further preferably 4 or less.
  • the maximum value ⁇ max of the light absorption coefficient in the wavelength range of 400 to 700 nm is preferably 1 m ⁇ 1 or less, more preferably 0.5 m ⁇ 1 or less, and still more preferably. 0.2 m ⁇ 1 or less.
  • ⁇ max is 1 m ⁇ 1 or less, the front luminance can be improved.
  • the total amount A of iron in the glass used as the glass plate 10 is preferably 100 ppm by mass or less in order to satisfy the above-described average internal transmittance at a wavelength of 400 to 700 nm at a length of 50 mm, and 40 ppm by mass. More preferably, it is more preferably 20 ppm by mass or less.
  • the total amount A of the iron content of the glass used as the glass plate 10 is preferably 5 ppm by mass or more in order to improve the meltability of the glass during the production of the multicomponent oxide glass, It is more preferably 8 ppm by mass or more, and further preferably 10 ppm by mass or more.
  • the total amount A of iron content of the glass used as the glass plate 10 can be adjusted by the amount of iron added at the time of glass production.
  • the total iron content A of the glass is expressed as the content of Fe 2 O 3 , but all the iron present in the glass exists as Fe 3+ (trivalent iron). I don't mean. Usually, Fe 3+ and Fe 2+ (divalent iron) are simultaneously present in the glass.
  • Fe 2+ and Fe 3+ have absorption in the wavelength range of 400 to 700 nm, but the absorption coefficient of Fe 2+ (11 cm ⁇ 1 Mol ⁇ 1 ) is more than that of Fe 3+ (0.96 cm ⁇ 1 Mol ⁇ 1 ). Therefore, the internal transmittance at a wavelength of 400 to 700 nm is further reduced. Therefore, a low content of Fe 2+ is preferable for increasing the internal transmittance at a wavelength of 400 to 700 nm.
  • the Fe 2+ content B of the glass used as the glass plate 10 is preferably 20 ppm by mass or less in order to satisfy the above-described average internal transmittance in the visible light region with the effective optical path length, and 10 ppm by mass or less. More preferably, it is more preferably 5 ppm by mass or less.
  • the Fe 2+ content B of the glass used as the glass plate 10 is preferably 0.01 mass ppm or more in order to improve the meltability of the glass during the production of multi-component oxide glass. 0.05 mass ppm or more is more preferable, and 0.1 mass ppm or more is further preferable.
  • the content A of Fe 2 O 3 was determined by fluorescent X-ray measurement, a content of total iron as calculated as Fe 2 O 3 (mass ppm).
  • the content B of Fe 2+ is measured according to ASTM C169-92 (2011). The measured Fe 2+ content is expressed in terms of Fe 2 O 3 .
  • One structural example (Structural Example A) of the glass used as the glass plate 10 is a mass percentage display based on an oxide, and SiO 2 is 60 to 80%, Al 2 O 3 is 0 to 7%, and MgO is 0 to 10%. %, CaO 0-20%, SrO 0-15%, BaO 0-15%, Na 2 O 3-20%, K 2 O 0-10%, Fe 2 O 3 5-100 mass Contains ppm.
  • FIG. 1 Another structural example (Structural Example B) of the glass used as the glass plate 10 is an oxide-based mass percentage display, with SiO 2 being 45-80%, Al 2 O 3 being more than 7% but not more than 30%, B 2 O 3 0-15%, MgO 0-15%, CaO 0-6%, SrO 0-5%, BaO 0-5%, Na 2 O 7-20%, K 2 O 0-10%, ZrO 2 0-10% and Fe 2 O 3 5-100 mass ppm.
  • SiO 2 being 45-80%
  • Al 2 O 3 being more than 7% but not more than 30%
  • B 2 O 3 0-15% MgO 0-15%
  • CaO 0-6% SrO 0-5%
  • BaO 0-5% Na 2 O 7-20%
  • K 2 O 0-10% K 2 O 0-10%
  • ZrO 2 0-10% ZrO 2 0-10%
  • Fe 2 O 3 5-100 mass ppm Another structural example (Stural Example B) of the
  • Still another structural example (Structural Example C) of the glass used as the glass plate 10 is an oxide-based mass percentage display, 45 to 70% of SiO 2 , 10 to 30% of Al 2 O 3 , B 2 0 to 15% of O 3 , 5 to 30% in total of MgO, CaO, SrO and BaO, 0% or more and less than 3% in total of Li 2 O, Na 2 O and K 2 O, Fe 2 O 3 Contains 5 to 100 ppm by mass.
  • composition range of each component of the glass composition of the glass plate 10 of the present embodiment having the above-described components will be described below.
  • the unit of the content of each composition is expressed in terms of mass percentage on the basis of oxide or mass ppm, and is simply expressed as “%” or “ppm”, respectively.
  • SiO 2 is a main component of glass.
  • the content of SiO 2 is preferably 60% or more, more preferably 63% or more in the configuration example A in terms of oxide-based mass percentage.
  • it is preferably 45% or more, more preferably 50% or more
  • Structural Example C it is preferably 45% or more, more preferably 50% or more.
  • the content of SiO 2 is easy to dissolve and the foam quality is good, and the content of divalent iron (Fe 2+ ) in the glass is kept low, and the optical properties are good. Therefore, in the configuration example A, preferably 80% or less, more preferably 75% or less, in the configuration example B, preferably 80% or less, more preferably 70% or less, and in the configuration example C , Preferably 70% or less, more preferably 65% or less.
  • Al 2 O 3 is an essential component that improves the weather resistance of the glass in Structural Examples B and C.
  • the content of Al 2 O 3 is preferably 1% or more, more preferably 2% or more in the configuration example A.
  • Example B it is preferably more than 7%, more preferably 10% or more
  • Structural Example C it is preferably 10% or more, more preferably 13% or more.
  • the content of Al 2 O 3 is preferably Is 7% or less, more preferably 5% or less.
  • the configuration example B preferably 30% or less, more preferably 23% or less
  • the configuration example C preferably 30% or less, more preferably 20% or less.
  • B 2 O 3 is a component that promotes melting of the glass raw material and improves mechanical properties or weather resistance, but it does not cause inconvenience such as formation of striae due to volatilization or furnace wall erosion.
  • the content of B 2 O 3 is preferably 5% or less, more preferably 3% or less.
  • the content is preferably 15% or less, more preferably 12%. It is as follows.
  • Alkali metal oxides such as Li 2 O, Na 2 O, and K 2 O are useful components for promoting melting of the glass raw material and adjusting thermal expansion or viscosity.
  • the content of Na 2 O is preferably 3% or more, more preferably 8% or more.
  • the content of Na 2 O is preferably 7% or more, and more preferably 10% or more.
  • the content of Na 2 O is preferably 20% or less in the structural examples A and B in order to maintain the clarity during melting and maintain the foam quality of the produced glass, and 15% More preferably, the content is set to 3% or less in the configuration example C, and more preferably 1% or less.
  • the content of K 2 O is preferably 10% or less, more preferably 7% or less in the structural examples A and B, and preferably 2% or less, more preferably in the structural example C. 1% or less.
  • Li 2 O is an optional component, but in the structural examples A, B, and C in order to facilitate vitrification, to keep the iron content contained as impurities derived from the raw material low, and to keep the batch cost low. , Li 2 O can be contained at 2% or less.
  • the total content of these alkali metal oxides maintains the clarification at the time of melting, and maintains the foam quality of the produced glass.
  • it is 5% to 20%, more preferably 8% to 15%.
  • it is preferably 0% to 2%, more preferably 0% to 1%.
  • Alkaline earth metal oxides such as MgO, CaO, SrO, and BaO are useful components for accelerating melting of glass raw materials and adjusting thermal expansion or viscosity.
  • MgO has the effect of lowering the viscosity during glass melting and promoting melting. Moreover, since it has the effect
  • CaO is a component that promotes melting of the glass raw material and adjusts viscosity or thermal expansion, and therefore can be contained in the structural examples A, B, and C.
  • the content of CaO is preferably 3% or more, more preferably 5% or more.
  • it is preferably 20% or less, more preferably 10% or less, and in the configuration example B, preferably 6% or less, more preferably 4% or less.
  • SrO has the effect of increasing the thermal expansion coefficient and lowering the high temperature viscosity of the glass.
  • SrO can be contained in the structural examples A, B, and C.
  • the content of SrO is preferably 15% or less in the structural examples A and C, more preferably 10% or less, and in the structural example B It is preferably 5% or less, and more preferably 3% or less.
  • BaO like SrO, has the effect of increasing the coefficient of thermal expansion and lowering the high temperature viscosity of the glass. In order to obtain the above effect, BaO can be contained. However, in order to keep the thermal expansion coefficient of the glass low, it is preferably 15% or less in Configuration Examples A and C, more preferably 10% or less, and 5% or less in Configuration Example B. Of these, 3% or less is more preferable.
  • the total content of these alkaline earth metal oxides is preferably 10 in the configuration example A in order to keep the coefficient of thermal expansion low, to improve the devitrification characteristics, and to maintain the strength.
  • % To 30% more preferably 13% to 27%.
  • In the configuration example B preferably 1% to 15%, more preferably 3% to 10%, and in the configuration example C, preferably 5%.
  • % To 30% more preferably 10% to 20%.
  • ZrO 2 is used as an optional component in the structural examples A, B and C, preferably 10% or less, preferably You may make it contain 5% or less. It becomes difficult to devitrify glass by setting it as 10% or less.
  • the glass composition of the glass plate 10 of the present embodiment 5 to 100 ppm of Fe 2 O 3 may be contained in the structural examples A, B, and C in order to improve the meltability of the glass.
  • the preferable range of the amount of Fe 2 O 3 is as described above.
  • the glass of the glass plate 10 of the present embodiment may contain SO 3 as a fining agent.
  • the SO 3 content is preferably more than 0% and 0.5% or less in terms of mass percentage. 0.4% or less is more preferable, 0.3% or less is more preferable, and 0.25% or less is further preferable.
  • the glass of the glass plate 10 of this embodiment may contain one or more of Sb 2 O 3 , SnO 2 and As 2 O 3 as an oxidizing agent and a fining agent.
  • the content of Sb 2 O 3 , SnO 2 or As 2 O 3 is preferably 0 to 0.5% in terms of mass percentage. 0.2% or less is more preferable, 0.1% or less is more preferable, and it is further more preferable not to contain substantially.
  • Sb 2 O 3 , SnO 2 and As 2 O 3 act as an oxidizing agent for glass, they may be added within the above range for the purpose of adjusting the amount of Fe 2+ in the glass. However, from the environmental aspect, it is preferable that As 2 O 3 is not substantially contained.
  • the glass of the glass plate 10 of this embodiment may contain NiO.
  • NiO functions also as a coloring component
  • the content of NiO is preferably 10 ppm or less with respect to the total amount of the glass composition described above.
  • NiO is preferably 1.0 ppm or less, and more preferably 0.5 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
  • the glass of the glass plate 10 of this embodiment may contain Cr 2 O 3 .
  • Cr 2 O 3 When Cr 2 O 3 is contained, Cr 2 O 3 also functions as a coloring component. Therefore, the content of Cr 2 O 3 is preferably 10 ppm or less with respect to the total amount of the glass composition described above.
  • Cr 2 O 3 is more preferably 1.0 ppm or less, and even more preferably 0.5 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
  • Glass of the glass plate 10 of the present embodiment may include TiO 2.
  • TiO 2 When TiO 2 is contained, TiO 2 also functions as a component that absorbs visible light. Therefore, the content of TiO 2 is preferably 1000 ppm or less with respect to the total amount of the glass composition described above. The content of TiO 2 is more preferably 500 ppm or less, and particularly preferably 100 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
  • the glass of the glass plate 10 of this embodiment may include at least one component selected from the group consisting of CoO, V 2 O 5 and CuO.
  • these components When these components are contained, they also function as components that absorb visible light, and therefore the content of the components is preferably 10 ppm or less with respect to the total amount of the glass composition described above. In particular, it is preferable that these components are not substantially contained so as not to lower the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
  • the glass plate 10 of the present invention has at least one or more bubbles in the inside thereof.
  • the luminance uniformity is high, and the edge light type planar light emitting device. It is suitable for use as a light guide plate.
  • the light guide plate 200 is the glass plate 10 of the present invention, and is opposed to the first main surface 11 of the glass plate 10 of the present invention, which serves as a light reflecting surface of the light guide plate 200.
  • the reflection member 300 is arranged.
  • Scattering members 400 are formed at predetermined intervals in a dot pattern on the first main surface 11 of the glass plate 10 of the present invention so as to be positioned between the glass plate 10 of the present invention and the reflecting member 300.
  • the scattering member may have another configuration as long as it can function as a light guide plate of the edge light type planar light emitting device.
  • the light from the light source is emitted from the second main surface 12 of the glass plate 10 of the present invention, which becomes the light emission surface of the light guide plate 200.
  • the glass plate 10 of the present invention has a ratio L max / L ave between the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ).
  • L max / L ave ⁇ 1.1 the luminance uniformity is high, and it is suitable for use as a light guide plate of an edge light type planar light emitting device.
  • a glass plate 10 of the present invention preferably has an average luminance L ave measured by the above procedure is 1000 cd / m 2 or more, more preferably 1200 cd / m 2 or more, is 1500 cd / m 2 or more More preferably.
  • the average luminance L ave is 1000 cd / m 2 or more, the visibility of the display image can be improved in a bright environment.
  • the luminance of the glass plate was measured according to the following procedure. (Brightness measurement) Diffusion ink was printed in a dot pattern on one main surface of a glass plate having at least one bubble inside, and a glass light guide plate having a scattering member formed on one main surface was produced. The dimension of this glass plate was 485 mm x 284 mm x t2 mm.
  • the absorption coefficient of light in the wavelength range of 400 to 700 nm was measured using an ultraviolet-visible near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science Co., Ltd.), the absorption coefficient of light having a wavelength of 550 nm was 0.04 m ⁇ 1. Met.
  • the maximum value ⁇ max of the light absorption coefficient in the wavelength range of 400 to 700 nm was 0.24 m ⁇ 1
  • the minimum value ⁇ min was 0.04 m ⁇ 1
  • ( ⁇ max / ⁇ min ) was 6. .
  • the glass plates of Examples 1 to 4 have the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ) in the luminance measurement performed in the above procedure,
  • the ratio L max / L ave satisfies 1 ⁇ L max / L ave ⁇ 1.1, so that the luminance uniformity is high and suitable for use as a light guide plate of an edge light type planar light emitting device. I found out.
  • the ratio L max / L ave between the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ) is 1.1 ⁇ L. Since max / L ave , the luminance uniformity was low.

Abstract

　The present invention provides a glass sheet that has high transmission in the visible light region and, when used as a light-guide plate of an edge-light-type surface light emitter, has high luminance uniformity. The present invention pertains to a glass sheet having a first main surface and a second main surface, wherein the glass sheet is characterized in that: the glass sheet has a coefficient of the absorption of 550-nm-wavelength light of 1m-1 or less; the ratio (αmax/αmin) of the maximum value αmax (m-1) of the coefficient of the absorption of 400-700-nm-wavelength light to the minimum value αmin (m-1) is 10 or less; one or more bubbles are present inside the glass sheet; and the ratio Lmax/Lave of the maximum luminance Lmax (cd/m2) to the average luminance Lave (cd/m2) of light emitted from the second main surface when light in the visible-light wavelength region is directed from a light source toward a reference end face is such that 1≤Lmax/Lave≤1.1.

Description

ガラス板Glass plate
　本発明は、エッジライト方式の面状発光装置の導光板として、好適に使用されるガラス板に関する。 The present invention relates to a glass plate suitably used as a light guide plate of an edge light type planar light emitting device.
　従来、携帯電話機、ＰＤＡ又は液晶テレビ等に液晶表示装置が用いられている。液晶表示装置は、バックライトとしての面状発光装置と、この面状発光装置の光出射面側に配置される液晶ユニットと、を基本構成とする。 Conventionally, liquid crystal display devices have been used for mobile phones, PDAs, liquid crystal televisions, and the like. The liquid crystal display device has a basic configuration of a planar light emitting device as a backlight and a liquid crystal unit disposed on the light emitting surface side of the planar light emitting device.
　面状発光装置としては、直下型とエッジライト型のものがある。直下型は光出射面に対して反対側となる背面に光源が配置されるため、光出射面と同程度の寸法の光源が必要になる。エッジライト型は光出射面に対して直交方向となる側面に光源が配置されるため、光出射面よりも寸法が小さい光源を使用できるため、液晶表示装置の大画面化に適している。 As the planar light emitting device, there are a direct type and an edge light type. In the direct type, the light source is arranged on the back surface opposite to the light emitting surface, and therefore a light source having the same size as the light emitting surface is required. The edge light type is suitable for increasing the screen of a liquid crystal display device because a light source is disposed on a side surface that is orthogonal to the light emitting surface, so that a light source having a smaller size than the light emitting surface can be used.
　また、このような面状発光装置には、建築物の天井、床若しくは壁等の屋内又は屋外に配置される面状照明装置としての需要も存在する。 Further, such a planar light emitting device also has a demand as a planar lighting device disposed indoors or outdoors such as a ceiling, floor or wall of a building.
　エッジライト方式の面状発光装置に使用される導光板ユニットの一構成例を図１に示す。図１に示す導光板ユニット１００は、側面に配置された光源（図示せず）からの光を全反射により内部に伝播させるとともに面状に出射させるための導光板２００、この導光板２００の主として光を出射する光出射面（図中、上面）に対して反対側となる光反射面（図中、下面）から出射する光を再び導光板２００に戻すための反射部材３００、および、その内部で全反射する光を散乱させて光出射面から出射させるとともに、光源が点光源である場合の光出射面における輝度の不均一、また光源からの距離の違いによる光出射面における輝度の不均一等を抑制する散乱部材４００で構成されている。 FIG. 1 shows a configuration example of a light guide plate unit used in an edge light type planar light emitting device. A light guide plate unit 100 shown in FIG. 1 has a light guide plate 200 for propagating light from a light source (not shown) arranged on a side surface to the inside by total reflection and emitting the light in a planar shape, and the light guide plate 200 mainly. Reflecting member 300 for returning light emitted from the light reflecting surface (lower surface in the figure) opposite to the light emitting surface (upper surface in the figure) that emits light to the light guide plate 200, and its interior In addition to scattering the totally reflected light at the light exit surface, the brightness is uneven on the light exit surface when the light source is a point light source, and the brightness unevenness on the light exit surface due to the difference in distance from the light source It is comprised by the scattering member 400 which suppresses etc.
　反射部材３００は、その主表面が、導光板２００の光反射面と対向するように配置された板状部材である。散乱部材４００は、導光板２００と、反射部材３００と、の間に位置するように、導光板２００の光反射面に、ドットパターン状に所定の間隔で形成されている。 The reflection member 300 is a plate-like member arranged so that its main surface faces the light reflection surface of the light guide plate 200. The scattering member 400 is formed on the light reflection surface of the light guide plate 200 at a predetermined interval in a dot pattern so as to be positioned between the light guide plate 200 and the reflection member 300.
　導光板ユニット１００の導光板２００としては、透過率が高いこと、比較的安価で入手が容易であること等の理由から、従来はアクリル樹脂又はポリカーボネート樹脂といった透明な樹脂材料製が用いられていた（特許文献１参照）。 The light guide plate 200 of the light guide plate unit 100 is conventionally made of a transparent resin material such as an acrylic resin or a polycarbonate resin because of its high transmittance, relatively low cost and easy availability. (See Patent Document 1).
　液晶表示装置の大画面化に対応するため、面状発光装置を大型化した場合、より高出力の光源が用いられる。これにより、光源の発熱量も多くなり、導光板にも耐熱性が要求されるようになる。上記した樹脂材料製の導光板は、ガラス転移点（Ｔｇ）が８０～１００℃（アクリル樹脂）、１４５～１５０℃（ポリカーボネート樹脂）と低いため耐熱性が不十分である。 In order to cope with an increase in the screen size of the liquid crystal display device, when the planar light emitting device is enlarged, a light source with higher output is used. As a result, the amount of heat generated by the light source increases and the light guide plate is also required to have heat resistance. The above light guide plate made of a resin material has insufficient heat resistance because the glass transition point (Tg) is as low as 80 to 100 ° C. (acrylic resin) and 145 to 150 ° C. (polycarbonate resin).
　上記した樹脂材料製の導光板よりも耐熱性に優れた導光板としては、ガラス材料製の導光板が提案されている（特許文献２参照）。ガラス材料の組成にもよるが、ガラス転移点（Ｔｇ）は５３０℃程度まで高めることができる。 A light guide plate made of a glass material has been proposed as a light guide plate having better heat resistance than the light guide plate made of a resin material (see Patent Document 2). Although it depends on the composition of the glass material, the glass transition point (Tg) can be increased to about 530 ° C.
日本国特開２０１１－２３３２８５号公報Japanese Unexamined Patent Publication No. 2011-233285 日本国特開２０１３－９３１９５号公報Japanese Unexamined Patent Publication No. 2013-93195
　エッジライト方式の面状発光装置の導光板として、ガラス板を使用する場合、ガラス板内部に存在する泡が問題となる。ガラス板を製造する場合、ガラス原料を溶解窯で溶解して溶融ガラスとした後、この溶融ガラスをガラス板に成形する。このガラス原料の溶解過程では、ＣＯ２、Ｈ２Ｏ、Ｏ２又はＳＯ２などのガスが放出され、このガスの一部は溶融ガラス中に泡として存在する。その結果、成形後のガラス板も、内部に泡が存在するものとなる。 When a glass plate is used as the light guide plate of the edge light type planar light emitting device, bubbles existing inside the glass plate become a problem. When manufacturing a glass plate, after melt | dissolving a glass raw material with a melting furnace and making it into molten glass, this molten glass is shape | molded into a glass plate. In the melting process of the glass raw material, a gas such as CO 2 , H 2 O, O 2 or SO 2 is released, and a part of this gas exists as bubbles in the molten glass. As a result, the glass plate after molding also has bubbles inside.
　従来、ガラス板の内部に存在する泡の量を低減するため、溶解槽の構造若しくはその内部の攪拌機構の改良、泡の発生若しくは成長を抑制するガラス組成の選択、または泡の発生若しくは成長を抑制する微量添加物の添加などの方法が実施されている。しかしながら、これらの方法により、ガラス板の内部に存在する泡の量を低減させることはできても、泡の量を限りなく０にすることは困難であった。 Conventionally, in order to reduce the amount of bubbles present in the glass plate, the structure of the melting tank or the stirring mechanism inside thereof is improved, the selection of a glass composition that suppresses the generation or growth of bubbles, or the generation or growth of bubbles. Methods such as the addition of trace trace additives to suppress are being implemented. However, even though these methods can reduce the amount of bubbles present inside the glass plate, it has been difficult to reduce the amount of bubbles to zero.
　導光板内部に存在する泡の影響については、樹脂材料製の導光板に関する特許文献１に記載されている。樹脂材料製の導光板内部に存在する泡は、その空孔径および空孔率が適切であれば、光路変更要素として作用することで、正面輝度の向上と輝度均一化の面で有効であるとされている。なお、樹脂材料製の導光板内部に存在する泡は、通常は球状である。 About the influence of the bubble which exists in the inside of a light-guide plate, it describes in patent document 1 regarding the light-guide plate made from a resin material. The bubbles present inside the light guide plate made of a resin material are effective in improving front luminance and uniform luminance by acting as an optical path changing element if the pore diameter and porosity are appropriate. Has been. The bubbles present inside the light guide plate made of a resin material are usually spherical.
　ガラス板に成形する際、ガラス２０中に存在する泡３０は、水平方向に引き伸ばされて、図２に示すように楕円形状となる。このような楕円形状の泡は、その向きと、光源から入射した光の進行方向と、の関係により、光路変更要素として作用が異なる。すなわち、正面輝度の向上と輝度均一化に寄与する場合もあれば、むしろ正面輝度の向上や輝度の均一化に悪影響を及ぼす場合もある。 When forming into a glass plate, the bubbles 30 present in the glass 20 are stretched in the horizontal direction and become elliptical as shown in FIG. Such an elliptical bubble functions differently as an optical path changing element depending on the relationship between its direction and the traveling direction of light incident from the light source. That is, there are cases where it contributes to the improvement of the front luminance and the luminance uniformity, and there are cases where it adversely affects the improvement of the front luminance and the uniformity of the luminance.
　また、溶融ガラス中に存在する泡の大きさは種々であり、また、上述したように、ガラス板製造時においては、ガラス板の内部に存在する泡の量を低減するための対策がなされているため、光路変更要素としての作用を期待するよりも、導光板として使用するガラス板内部に存在する泡は、導光板の光学特性に影響を及ぼさないほうが好ましい。 In addition, the size of bubbles present in the molten glass is various, and as described above, measures are taken to reduce the amount of bubbles present in the glass plate during the production of the glass plate. Therefore, it is preferable that bubbles existing inside the glass plate used as the light guide plate do not affect the optical characteristics of the light guide plate, rather than expecting an action as an optical path changing element.
　さらにまた、導光板として使用するガラス板について、内部に存在する泡を観察して、楕円形状の泡の寸法や、その向きを特定し、光源から入射する光の進行方向を設定するのは現実的ではない。 Furthermore, it is real to set the traveling direction of light incident from the light source by observing the bubbles present inside the glass plate used as the light guide plate, specifying the size and direction of the elliptical bubbles. Not right.
　本発明は、上述した従来技術における問題点を解決するため、可視光域の透過性が高く、かつ、エッジライト方式の面状発光装置の導光板として使用した場合に輝度の均一性が高いガラス板を提供することを目的とする。 In order to solve the above-mentioned problems in the prior art, the present invention is a glass having high transparency in the visible light region and high luminance uniformity when used as a light guide plate of an edge light type planar light emitting device. The purpose is to provide a board.
　上記した目的を達成するため、本発明は、第１主表面、前記第１主表面に対向する第２主表面、並びに、前記第１主表面および前記第２主表面を接続する端面からなり、前記第１主表面および前記第２主表面を持つガラス板において、
　前記ガラス板は、波長５５０ｎｍの光の吸収係数が１ｍ－１以下であり、波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘ（ｍ－１）と、最小値αｍｉｎ（ｍ－１）と、の比（αｍａｘ／αｍｉｎ）が１０以下であり、前記ガラス板内部には少なくとも１つ以上の泡が存在し、
　前記第１主表面に面するように反射部材及び散乱部材を配置し、前記端面のうちの一つを基準端面とするとき、前記基準端面に面するように光源を配置して、前記光源から前記基準端面に向けて可視光の波長域の光を照射した際の、前記第２主表面からの出射光における、最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）と、の比Ｌｍａｘ／Ｌａｖｅが、１≦Ｌｍａｘ／Ｌａｖｅ≦１．１を満足することを特徴とするガラス板。 In order to achieve the above object, the present invention comprises a first main surface, a second main surface facing the first main surface, and an end face connecting the first main surface and the second main surface, In the glass plate having the first main surface and the second main surface,
The glass plate has a light absorption coefficient of 1 m −1 or less at a wavelength of 550 nm, a maximum value α max (m −1 ) of light absorption coefficient in a wavelength range of 400 to 700 nm and a minimum value α min (m − 1 ) and the ratio (α max / α min ) of 10 or less, and at least one bubble is present inside the glass plate,
When a reflecting member and a scattering member are disposed so as to face the first main surface, and one of the end surfaces is a reference end surface, a light source is disposed so as to face the reference end surface, The maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m) in the light emitted from the second main surface when light in the visible wavelength range is irradiated toward the reference end face. 2 ) and the ratio L max / L ave satisfies 1 ≦ L max / L ave ≦ 1.1.
　本発明のガラス板は、波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘが１ｍ－１以下であることが好ましく、より好ましくは０．５ｍ－１以下であり、さらに好ましくは０．２ｍ－１以下である。αｍａｘが１ｍ－１以下であることにより導光板として使用した場合、正面輝度を向上できる。 In the glass plate of the present invention, the maximum value α max of the light absorption coefficient in the wavelength range of 400 to 700 nm is preferably 1 m −1 or less, more preferably 0.5 m −1 or less, and even more preferably 0. .2m -1 or less. When α max is 1 m −1 or less, the front luminance can be improved when used as a light guide plate.
　本発明のガラス板は、前記第１主表面および前記第２主表面が実質的に矩形であり、少なくとも１辺の長さが２００ｍｍ以上であり、前記ガラス板の板厚が０．５～１０ｍｍ、前記ガラスの板厚の公差が±０．１ｍｍ以内であることが好ましい。 In the glass plate of the present invention, the first main surface and the second main surface are substantially rectangular, the length of at least one side is 200 mm or more, and the thickness of the glass plate is 0.5 to 10 mm. The thickness tolerance of the glass is preferably within ± 0.1 mm.
　本発明のガラス板は、前記第２主表面からの出射光における、平均輝度Ｌａｖｅが１０００ｃｄ／ｍ２以上であることが好ましい。 The glass plate of the present invention preferably has an average luminance L ave of 1000 cd / m 2 or more in the light emitted from the second main surface.
　本発明のガラス板は、可視光域の透過性が高く、かつ、エッジライト方式の面状発光装置の導光板として使用した場合に輝度の均一性が高いため、エッジライト方式の面状発光装置の導光板として好適である。 The glass plate of the present invention has high transparency in the visible light region and high uniformity of brightness when used as a light guide plate of an edge light type planar light emitting device. It is suitable as a light guide plate.
図１は、導光板ユニットの一構成例を示した模式断面図である。FIG. 1 is a schematic cross-sectional view showing a configuration example of a light guide plate unit. 図２は、ガラス板内部に存在する泡の形状を説明するための模式図である。FIG. 2 is a schematic diagram for explaining the shape of bubbles present inside the glass plate. 図３は、本発明のガラス板の一構成例を示した斜視図である。FIG. 3 is a perspective view showing one structural example of the glass plate of the present invention.
　以下、本発明のガラス板について説明する。なお、本明細書において「～」とはその前後に記載される数値を下限値及び上限値として含む意味で使用される。 Hereinafter, the glass plate of the present invention will be described. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
　図３は、本発明のガラス板の一構成例を示した斜視図である。図３に示すガラス板１０は、第１主表面１１、第１主表面１１に対向する第２主表面１２、並びに、第１主表面１１および第２主表面１２を接続する端面１３からなり、第１主表面１１および第２主表面１２が実質的に矩形である。但し、本発明のガラス板において、第１主表面および第２主表面の形状は実質的に矩形に限定されず、他の形状であってもよい。 FIG. 3 is a perspective view showing one structural example of the glass plate of the present invention. The glass plate 10 shown in FIG. 3 includes a first main surface 11, a second main surface 12 facing the first main surface 11, and an end face 13 connecting the first main surface 11 and the second main surface 12. The first main surface 11 and the second main surface 12 are substantially rectangular. However, in the glass plate of the present invention, the shapes of the first main surface and the second main surface are not substantially limited to rectangles, and may be other shapes.
　本発明のガラス板における第１主表面１１、および、第２主表面１２は、輝度測定の際、反射部材及び散乱部材を配置する側を特定するため、ガラス板の２つの主表面を、便宜的に第１主表面１１、および、第２主表面１２と定めたものである。したがって、ガラス板の２つの主表面のうち、どちらの面を第１主表面（第２主表面）としてもよい。 The first main surface 11 and the second main surface 12 in the glass plate of the present invention specify the two main surfaces of the glass plate for convenience in order to specify the side on which the reflecting member and the scattering member are arranged at the time of luminance measurement. Specifically, the first main surface 11 and the second main surface 12 are defined. Therefore, either surface of the two main surfaces of the glass plate may be the first main surface (second main surface).
　但し、本発明のガラス板を、エッジライト方式の面状発光装置の導光板として使用する場合に、ガラス板の２つの主表面のうち、どちらの面を導光板の光出射面（光反射面）とするか、あらかじめ決まっている場合、光反射面を第１主表面とし、光出射面を第２主表面とすることが好ましい。 However, when the glass plate of the present invention is used as a light guide plate of an edge light type planar light emitting device, one of the two main surfaces of the glass plate is the light emitting surface (light reflecting surface) of the light guide plate. Or the light reflecting surface is preferably the first main surface and the light emitting surface is preferably the second main surface.
　また、図３に示すガラス板１０は、第１主表面１１、および、第２主表面１２の形状が長方形であるが、第１主表面１１、および、第２主表面１２の形状は正方形でもよい。さらには、ケース枠内に固定するために、切り欠けを設けてもよい。 Further, in the glass plate 10 shown in FIG. 3, the first main surface 11 and the second main surface 12 have a rectangular shape, but the first main surface 11 and the second main surface 12 may have a square shape. Good. Further, a notch may be provided for fixing in the case frame.
　本発明のガラス板１０の寸法のうち、ガラス板の主表面（第１主表面１１、第２主表面１２）の一辺の長さは、本発明のガラス板を導光板として使用する面状発光装置の寸法により異なる。たとえば、面状発光装置がエッジライト方式の液晶テレビの場合、ガラス板の主表面（第１主表面１１、第２主表面１２）の一辺の長さは、２００ｍｍ以上であることが好ましく、２５０ｍｍ以上であることがより好ましく、４００ｎｍ以上であることがさらに好ましい。 Among the dimensions of the glass plate 10 of the present invention, the length of one side of the main surface (first main surface 11 and second main surface 12) of the glass plate is a planar light emission using the glass plate of the present invention as a light guide plate. It depends on the dimensions of the device. For example, when the planar light emitting device is an edge light type liquid crystal television, the length of one side of the main surface (first main surface 11 and second main surface 12) of the glass plate is preferably 200 mm or more, and 250 mm. More preferably, it is more preferably 400 nm or more.
　一方、本発明のガラス板１０の寸法のうち、ガラス板の板厚（端面１３の厚さ）は、０．５～１０ｍｍであることが好ましい。導光板として使用されるガラス板の内部透過率は、ガラス部材の厚さにより影響される。 On the other hand, among the dimensions of the glass plate 10 of the present invention, the thickness of the glass plate (the thickness of the end face 13) is preferably 0.5 to 10 mm. The internal transmittance of the glass plate used as the light guide plate is affected by the thickness of the glass member.
　ガラス板の板厚が０．５ｍｍ以上であると、導光板としての使用時において、ガラス表面で反射する回数が増加するのを防ぎ、反射による減衰が大きくなり有効光路長での内部透過率が低下するのを防ぐことができる。より好ましくは１ｍｍ以上であり、さらに好ましくは１．５ｍｍ以上である。 When the thickness of the glass plate is 0.5 mm or more, when used as a light guide plate, the number of reflections on the glass surface is prevented from increasing, the attenuation due to reflection increases, and the internal transmittance at the effective optical path length is increased. It can be prevented from lowering. More preferably, it is 1 mm or more, More preferably, it is 1.5 mm or more.
　一方、ガラス板の板厚が１０ｍｍ以下であると、図１に示す導光板ユニット１００の導光板２００として使用する際、散乱部材４００に散乱される回数が減少するのを防ぎ、外に取り出される光量が減少するのを抑制することができ、内部透過率が向上する。より好ましくは５ｍｍ以下であり、さらに好ましくは２．５ｍｍ以下である。 On the other hand, when the plate thickness of the glass plate is 10 mm or less, when used as the light guide plate 200 of the light guide plate unit 100 shown in FIG. A decrease in the amount of light can be suppressed, and the internal transmittance is improved. More preferably, it is 5 mm or less, More preferably, it is 2.5 mm or less.
　また、ガラス板の板厚の公差が±０．１ｍｍ以内であることが好ましく、より好ましくは±０．０８ｍｍ以内であり、さらに好ましくは±０．０５ｍｍ以内である。ガラス板の板厚の公差が±０．１ｍｍ以内であることにより、光源からガラス板への入光を安定にすることが可能となり、面内の輝度の均一性を向上させることが可能である。 Further, the thickness tolerance of the glass plate is preferably within ± 0.1 mm, more preferably within ± 0.08 mm, and even more preferably within ± 0.05 mm. When the tolerance of the thickness of the glass plate is within ± 0.1 mm, it is possible to stabilize the light incident from the light source to the glass plate and improve the in-plane luminance uniformity. .
　本発明のガラス板１０は、エッジライト方式の面状発光装置の導光板として使用されるため、面状発光装置の光源の波長域で光の吸収係数が低いことが好ましい。面状発光装置がエッジライト方式の液晶テレビの場合、光源としては、発光ダイオード（ＬＥＤ）、具体的には、Ｒ（赤）、Ｇ（緑）及びＢ（青）の三色のＬＥＤが使用される。そのため、これら三色の光の吸収係数が低いことが好ましい。 Since the glass plate 10 of the present invention is used as a light guide plate of an edge light type planar light emitting device, it is preferable that the light absorption coefficient is low in the wavelength range of the light source of the planar light emitting device. When the planar light-emitting device is an edge-light type liquid crystal television, a light-emitting diode (LED) is used as a light source, specifically, R (red), G (green) and B (blue) LEDs are used. Is done. Therefore, it is preferable that the absorption coefficient of light of these three colors is low.
　本発明のガラス板１０は、波長５５０ｎｍの光の吸収係数が１ｍ－１以下であり、波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘ（ｍ－１）と、最小値αｍｉｎ（ｍ－１）と、の比（αｍａｘ／αｍｉｎ）が１０以下である。 The glass plate 10 of the present invention has a light absorption coefficient of 1 m −1 or less at a wavelength of 550 nm, a maximum value α max (m −1 ) of a light absorption coefficient in a wavelength range of 400 to 700 nm, and a minimum value α min. The ratio (α max / α min ) to (m −1 ) is 10 or less.
　波長５５０ｎｍの光の吸収係数は、好ましくは０．５ｍ－１以下であり、より好ましくは０．２ｍ－１以下であり、さらに好ましくは０．１ｍ－１以下である。また、前記（αｍａｘ／αｍｉｎ）は、好ましくは７以下であり、より好ましくは５以下であり、さらに好ましくは４以下である。 The absorption coefficient of light having a wavelength of 550 nm is preferably 0.5 m −1 or less, more preferably 0.2 m −1 or less, and even more preferably 0.1 m −1 or less. The (α max / α min ) is preferably 7 or less, more preferably 5 or less, and further preferably 4 or less.
　ここで、波長４００～７００ｎｍの範囲の光の吸収係数を判断指標とするのは、Ｒ（赤）、Ｇ（緑）及びＢ（青）の三色の光の波長を包含するからである。また、波長５５０ｎｍの光の吸収係数を判断指標とするのは、波長４００～７８０ｎｍの範囲の光のうち、波長５５０ｎｍの光の吸収係数が最も低くなるからである。 Here, the reason why the light absorption coefficient in the wavelength range of 400 to 700 nm is used as a judgment index is that it includes the wavelengths of light of three colors of R (red), G (green), and B (blue). The reason why the absorption coefficient of light having a wavelength of 550 nm is used as a determination index is that the absorption coefficient of light having a wavelength of 550 nm is the lowest among the light having a wavelength of 400 to 780 nm.
　波長５５０ｎｍの光の吸収係数、および、波長４００～７８０ｎｍの範囲の光の吸収係数の最大値αｍａｘ（ｍ－１）と、最小値αｍｉｎ（ｍ－１）と、の比（αｍａｘ／αｍｉｎ）が前記の条件を満たしていれば、面状発光装置がエッジライト方式の液晶テレビの光源として使用される、Ｒ（赤）、Ｇ（緑）及びＢ（青）の三色の光の吸収が軽微である。また、αｍａｘ／αｍｉｎが前記の条件を満たしていれば、波長４００～７００ｎｍの範囲において、波長による光の吸収の差が軽微である。 The ratio (α max / m) of the maximum value α max (m −1 ) and the minimum value α min (m −1 ) of the light absorption coefficient at a wavelength of 550 nm and the light absorption coefficient in the wavelength range of 400 to 780 nm. If α min ) satisfies the above condition, the light of the three colors R (red), G (green), and B (blue) is used as the light source of the edge light type liquid crystal television. Absorption of is slight. If α max / α min satisfies the above conditions, the difference in light absorption depending on the wavelength is slight in the wavelength range of 400 to 700 nm.
　本発明のガラス板１０は、波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘが１ｍ－１以下であることが好ましく、より好ましくは０．５ｍ－１以下であり、さらに好ましくは０．２ｍ－１以下である。αｍａｘが１ｍ－１以下であることにより、正面輝度を向上できる。 In the glass plate 10 of the present invention, the maximum value α max of the light absorption coefficient in the wavelength range of 400 to 700 nm is preferably 1 m −1 or less, more preferably 0.5 m −1 or less, and still more preferably. 0.2 m −1 or less. When α max is 1 m −1 or less, the front luminance can be improved.
　ガラス板１０として用いられるガラスの鉄の含有量の総量Ａは、１００質量ｐｐｍ以下であることが、上述した５０ｍｍ長での波長４００～７００ｎｍにおける平均内部透過率を満たすうえで好ましく、４０質量ｐｐｍ以下であることがより好ましく、２０質量ｐｐｍ以下であることがさらに好ましい。 The total amount A of iron in the glass used as the glass plate 10 is preferably 100 ppm by mass or less in order to satisfy the above-described average internal transmittance at a wavelength of 400 to 700 nm at a length of 50 mm, and 40 ppm by mass. More preferably, it is more preferably 20 ppm by mass or less.
　一方、ガラス板１０として用いられるガラスの鉄の含有量の総量Ａは、５質量ｐｐｍ以上であることが、多成分系の酸化物ガラス製造時において、ガラスの熔解性を向上させるうえで好ましく、８質量ｐｐｍ以上であることがより好ましく、１０質量ｐｐｍ以上であることがさらに好ましい。なお、ガラス板１０として用いられるガラスの鉄の含有量の総量Ａは、ガラス製造時に添加する鉄の量により調節できる。 On the other hand, the total amount A of the iron content of the glass used as the glass plate 10 is preferably 5 ppm by mass or more in order to improve the meltability of the glass during the production of the multicomponent oxide glass, It is more preferably 8 ppm by mass or more, and further preferably 10 ppm by mass or more. In addition, the total amount A of iron content of the glass used as the glass plate 10 can be adjusted by the amount of iron added at the time of glass production.
　本明細書においては、ガラスの鉄の含有量の総量Ａを、Ｆｅ２Ｏ３の含有量として表しているが、ガラス中に存在する鉄がすべてＦｅ３＋（３価の鉄）として存在しているわけではない。通常、ガラス中にはＦｅ３＋とＦｅ２＋（２価の鉄）が同時に存在している。 In this specification, the total iron content A of the glass is expressed as the content of Fe 2 O 3 , but all the iron present in the glass exists as Fe 3+ (trivalent iron). I don't mean. Usually, Fe 3+ and Fe 2+ (divalent iron) are simultaneously present in the glass.
　Ｆｅ２＋およびＦｅ３＋は、波長４００～７００ｎｍの範囲に吸収が存在するが、Ｆｅ２＋の吸収係数（１１ｃｍ－１Ｍｏｌ－１）はＦｅ３＋の吸収係数（０．９６ｃｍ－１Ｍｏｌ－１）よりも１桁大きいため、波長４００～７００ｎｍにおける内部透過率をより低下させる。そのため、Ｆｅ２＋の含有量が少ないことが、波長４００～７００ｎｍにおける内部透過率を高めるうえで好ましい。 Fe 2+ and Fe 3+ have absorption in the wavelength range of 400 to 700 nm, but the absorption coefficient of Fe 2+ (11 cm −1 Mol −1 ) is more than that of Fe 3+ (0.96 cm −1 Mol −1 ). Therefore, the internal transmittance at a wavelength of 400 to 700 nm is further reduced. Therefore, a low content of Fe 2+ is preferable for increasing the internal transmittance at a wavelength of 400 to 700 nm.
　ガラス板１０として用いられるガラスのＦｅ２＋の含有量Ｂは、２０質量ｐｐｍ以下であることが、有効光路長で上述した可視光域の平均内部透過率を満たすうえで好ましく、１０質量ｐｐｍ以下であることがより好ましく、５質量ｐｐｍ以下であることがさらに好ましい。 The Fe 2+ content B of the glass used as the glass plate 10 is preferably 20 ppm by mass or less in order to satisfy the above-described average internal transmittance in the visible light region with the effective optical path length, and 10 ppm by mass or less. More preferably, it is more preferably 5 ppm by mass or less.
　一方、ガラス板１０として用いられるガラスのＦｅ２＋の含有量Ｂは、０．０１質量ｐｐｍ以上であることが、多成分系の酸化物ガラス製造時において、ガラスの熔解性を向上させるうえで好ましく、０．０５質量ｐｐｍ以上であることがより好ましく、０．１質量ｐｐｍ以上であることがさらに好ましい。 On the other hand, the Fe 2+ content B of the glass used as the glass plate 10 is preferably 0.01 mass ppm or more in order to improve the meltability of the glass during the production of multi-component oxide glass. 0.05 mass ppm or more is more preferable, and 0.1 mass ppm or more is further preferable.
　なお、ガラス板１０として用いられるガラスのＦｅ２＋の含有量は、ガラス製造時に添加する酸化剤の量、または溶解温度等により調節できる。ガラス製造時に添加する酸化剤の具体的な種類とそれらの添加量については後述する。 In addition, content of Fe <2+> of the glass used as the glass plate 10 can be adjusted with the quantity of the oxidizing agent added at the time of glass manufacture, or a melting temperature. Specific types of oxidizers added during glass production and their addition amounts will be described later.
　Ｆｅ２Ｏ３の含有量Ａは、蛍光Ｘ線測定によって求めた、Ｆｅ２Ｏ３に換算した全鉄の含有量（質量ｐｐｍ）である。Ｆｅ２＋の含有量ＢはＡＳＴＭ　Ｃ１６９－９２（２０１１年）に準じて測定する。なお、測定されるＦｅ２＋の含有量はＦｅ２Ｏ３に換算して表記する。 The content A of Fe 2 O 3 was determined by fluorescent X-ray measurement, a content of total iron as calculated as Fe 2 O 3 (mass ppm). The content B of Fe 2+ is measured according to ASTM C169-92 (2011). The measured Fe 2+ content is expressed in terms of Fe 2 O 3 .
　ガラス板１０として用いられるガラスの組成の具体例を以下に示す。但し、ガラス板１０として用いられるガラスの組成はこれらに限定されない。 Specific examples of the composition of the glass used as the glass plate 10 are shown below. However, the composition of the glass used as the glass plate 10 is not limited to these.
　ガラス板１０として用いられるガラスの一構成例（構成例Ａ）は、酸化物基準の質量百分率表示で、ＳｉＯ２を６０～８０％、Ａｌ２Ｏ３を０～７％、ＭｇＯを０～１０％、ＣａＯを０～２０％、ＳｒＯを０～１５％、ＢａＯを０～１５％、Ｎａ２Ｏを３～２０％、Ｋ２Ｏを０～１０％、Ｆｅ２Ｏ３を５～１００質量ｐｐｍ含む。 One structural example (Structural Example A) of the glass used as the glass plate 10 is a mass percentage display based on an oxide, and SiO 2 is 60 to 80%, Al 2 O 3 is 0 to 7%, and MgO is 0 to 10%. %, CaO 0-20%, SrO 0-15%, BaO 0-15%, Na 2 O 3-20%, K 2 O 0-10%, Fe 2 O 3 5-100 mass Contains ppm.
　ガラス板１０として用いられるガラスの別の一構成例（構成例Ｂ）は、酸化物基準の質量百分率表示で、ＳｉＯ２を４５～８０％、Ａｌ２Ｏ３を７％超３０％以下、Ｂ２Ｏ３を０～１５％、ＭｇＯを０～１５％、ＣａＯを０～６％、ＳｒＯを０～５％、ＢａＯを０～５％、Ｎａ２Ｏを７～２０％、Ｋ２Ｏを０～１０％、ＺｒＯ２を０～１０％、Ｆｅ２Ｏ３を５～１００質量ｐｐｍ含む。 Another structural example (Structural Example B) of the glass used as the glass plate 10 is an oxide-based mass percentage display, with SiO 2 being 45-80%, Al 2 O 3 being more than 7% but not more than 30%, B 2 O 3 0-15%, MgO 0-15%, CaO 0-6%, SrO 0-5%, BaO 0-5%, Na 2 O 7-20%, K 2 O 0-10%, ZrO 2 0-10% and Fe 2 O 3 5-100 mass ppm.
　ガラス板１０として用いられるガラスのさらに別の一構成例（構成例Ｃ）は、酸化物基準の質量百分率表示で、ＳｉＯ２を４５～７０％、Ａｌ２Ｏ３を１０～３０％、Ｂ２Ｏ３を０～１５％、ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯを合計で５～３０％、Ｌｉ２Ｏ、Ｎａ２ＯおよびＫ２Ｏを合計で０％以上、３％未満、Ｆｅ２Ｏ３を５～１００質量ｐｐｍ含む。 Still another structural example (Structural Example C) of the glass used as the glass plate 10 is an oxide-based mass percentage display, 45 to 70% of SiO 2 , 10 to 30% of Al 2 O 3 , B 2 0 to 15% of O 3 , 5 to 30% in total of MgO, CaO, SrO and BaO, 0% or more and less than 3% in total of Li 2 O, Na 2 O and K 2 O, Fe 2 O 3 Contains 5 to 100 ppm by mass.
　しかしながら、ガラス板１０として用いられるガラスはこれらに限定されるものではない。 However, the glass used as the glass plate 10 is not limited to these.
　上記した成分を有する本実施形態のガラス板１０のガラスの組成の各成分の組成範囲について、以下に説明する。なお、各組成の含有量の単位はいずれも酸化物基準の質量百分率表示または質量ｐｐｍ表示であり、それぞれ単に「％」「ｐｐｍ」と表す。 The composition range of each component of the glass composition of the glass plate 10 of the present embodiment having the above-described components will be described below. The unit of the content of each composition is expressed in terms of mass percentage on the basis of oxide or mass ppm, and is simply expressed as “%” or “ppm”, respectively.
　ＳｉＯ２は、ガラスの主成分である。ＳｉＯ２の含有量は、ガラスの耐候性、失透特性を保つため、酸化物基準の質量百分率表示で、構成例Ａにおいては、好ましくは６０％以上、より好ましくは６３％以上であり、構成例Ｂにおいては、好ましくは４５％以上、より好ましくは５０％以上であり、構成例Ｃにおいては、好ましくは４５％以上、より好ましくは５０％以上である。 SiO 2 is a main component of glass. In order to maintain the weather resistance and devitrification characteristics of the glass, the content of SiO 2 is preferably 60% or more, more preferably 63% or more in the configuration example A in terms of oxide-based mass percentage. In Example B, it is preferably 45% or more, more preferably 50% or more, and in Structural Example C, it is preferably 45% or more, more preferably 50% or more.
　一方、ＳｉＯ２の含有量は、溶解を容易にし、泡品質を良好なものとするために、またガラス中の二価鉄（Ｆｅ２＋）の含有量を低く抑え、光学特性を良好なものとするため、構成例Ａにおいては、好ましくは８０％以下、より好ましくは７５％以下であり、構成例Ｂにおいては、好ましくは８０％以下、より好ましくは７０％以下であり、構成例Ｃにおいては、好ましくは７０％以下、より好ましくは６５％以下である。 On the other hand, the content of SiO 2 is easy to dissolve and the foam quality is good, and the content of divalent iron (Fe 2+ ) in the glass is kept low, and the optical properties are good. Therefore, in the configuration example A, preferably 80% or less, more preferably 75% or less, in the configuration example B, preferably 80% or less, more preferably 70% or less, and in the configuration example C , Preferably 70% or less, more preferably 65% or less.
　Ａｌ２Ｏ３は、構成例Ｂ及びＣにおいてはガラスの耐候性を向上させる必須成分である。本実施形態のガラスにおいて実用上必要な耐候性を維持するためには、Ａｌ２Ｏ３の含有量は、構成例Ａにおいては、好ましくは１％以上、より好ましくは２％以上であり、構成例Ｂにおいては、好ましくは７％超、より好ましくは１０％以上であり、構成例Ｃにおいては、好ましくは１０％以上、より好ましくは１３％以上である。 Al 2 O 3 is an essential component that improves the weather resistance of the glass in Structural Examples B and C. In order to maintain practically necessary weather resistance in the glass of the present embodiment, the content of Al 2 O 3 is preferably 1% or more, more preferably 2% or more in the configuration example A. In Example B, it is preferably more than 7%, more preferably 10% or more, and in Structural Example C, it is preferably 10% or more, more preferably 13% or more.
　但し、二価鉄（Ｆｅ２＋）の含有量を低く抑え、光学特性を良好なものとし、泡品質を良好なものとするため、Ａｌ２Ｏ３の含有量は、構成例Ａにおいては、好ましくは７％以下、より好ましくは５％以下であり、構成例Ｂにおいては、好ましくは３０％以下、より好ましくは２３％以下であり、構成例Ｃにおいては、好ましくは３０％以下、より好ましくは、２０％以下である。 However, in order to keep the content of divalent iron (Fe 2+ ) low, make the optical properties good, and make the foam quality good, the content of Al 2 O 3 is preferably Is 7% or less, more preferably 5% or less. In the configuration example B, preferably 30% or less, more preferably 23% or less, and in the configuration example C, preferably 30% or less, more preferably 20% or less.
　Ｂ２Ｏ３は、ガラス原料の溶融を促進し、機械的特性又は耐候性を向上させる成分であるが、揮発による脈理（ｒｅａｍ）の生成又は炉壁の侵食等の不都合が生じないために、Ｂ２Ｏ３の含有量は、ガラスＡにおいては、好ましくは５％以下、より好ましくは３％以下であり、構成例Ｂ及びＣにおいては、好ましくは１５％以下、より好ましくは、１２％以下である。 B 2 O 3 is a component that promotes melting of the glass raw material and improves mechanical properties or weather resistance, but it does not cause inconvenience such as formation of striae due to volatilization or furnace wall erosion. In the glass A, the content of B 2 O 3 is preferably 5% or less, more preferably 3% or less. In the structural examples B and C, the content is preferably 15% or less, more preferably 12%. It is as follows.
　Ｌｉ２Ｏ、Ｎａ２Ｏ、及び、Ｋ２Ｏといったアルカリ金属酸化物は、ガラス原料の溶融を促進し、熱膨張又は粘性等を調整するのに有用な成分である。 Alkali metal oxides such as Li 2 O, Na 2 O, and K 2 O are useful components for promoting melting of the glass raw material and adjusting thermal expansion or viscosity.
　そのため、Ｎａ２Ｏの含有量は、構成例Ａにおいては、好ましくは３％以上、より好ましくは、８％以上である。Ｎａ２Ｏの含有量は、構成例Ｂにおいては、好ましくは７％以上、より好ましくは、１０％以上である。但し、溶解時の清澄性を保持し、製造されるガラスの泡品質を保つために、Ｎａ２Ｏの含有量は、構成例Ａ及びＢにおいては、２０％以下とするのが好ましく、１５％以下とするのがさらに好ましく、構成例Ｃにおいては、３％以下とするのが好ましく、１％以下とするのがより好ましい。 Therefore, in the configuration example A, the content of Na 2 O is preferably 3% or more, more preferably 8% or more. In the structural example B, the content of Na 2 O is preferably 7% or more, and more preferably 10% or more. However, the content of Na 2 O is preferably 20% or less in the structural examples A and B in order to maintain the clarity during melting and maintain the foam quality of the produced glass, and 15% More preferably, the content is set to 3% or less in the configuration example C, and more preferably 1% or less.
　また、Ｋ２Ｏの含有量は、構成例Ａ及びＢにおいては、好ましくは１０％以下、より好ましくは、７％以下であり、構成例Ｃにおいては、好ましくは２％以下、より好ましくは、１％以下である。 Further, the content of K 2 O is preferably 10% or less, more preferably 7% or less in the structural examples A and B, and preferably 2% or less, more preferably in the structural example C. 1% or less.
　また、Ｌｉ２Ｏは、任意成分であるが、ガラス化を容易にし、原料に由来する不純物として含まれる鉄含有量を低く抑え、バッチコストを低く抑えるために、構成例Ａ、Ｂ及びＣにおいて、Ｌｉ２Ｏを２％以下含有させることができる。 In addition, Li 2 O is an optional component, but in the structural examples A, B, and C in order to facilitate vitrification, to keep the iron content contained as impurities derived from the raw material low, and to keep the batch cost low. , Li 2 O can be contained at 2% or less.
　また、これらアルカリ金属酸化物の合計含有量（Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ）は、溶解時の清澄性を保持し、製造されるガラスの泡品質を保つために、構成例Ａ及びＢにおいては、好ましくは５％～２０％、より好ましくは８％～１５％であり、構成例Ｃにおいては、好ましくは０％～２％、より好ましくは、０％～１％である。 In addition, in the configuration examples A and B, the total content of these alkali metal oxides (Li 2 O + Na 2 O + K 2 O) maintains the clarification at the time of melting, and maintains the foam quality of the produced glass. Preferably, it is 5% to 20%, more preferably 8% to 15%. In the configuration example C, it is preferably 0% to 2%, more preferably 0% to 1%.
　ＭｇＯ、ＣａＯ、ＳｒＯ、及びＢａＯといったアルカリ土類金属酸化物は、ガラス原料の溶融を促進し、熱膨張又は粘性等を調整するのに有用な成分である。 Alkaline earth metal oxides such as MgO, CaO, SrO, and BaO are useful components for accelerating melting of glass raw materials and adjusting thermal expansion or viscosity.
　ＭｇＯは、ガラス溶解時の粘性を下げ、溶解を促進する作用がある。また、比重を低減させ、ガラス板に疵をつきにくくする作用があるために、構成例Ａ、Ｂ及びＣにおいて、含有させることができる。また、ガラスの熱膨張係数を低く、失透特性を良好なものとするために、ＭｇＯの含有量は、構成例Ａにおいては、好ましくは１０％以下、より好ましくは８％以下であり、構成例Ｂにおいては、好ましくは１５％以下、より好ましくは１２％以下であり、構成例Ｃにおいては、好ましくは１０％以下、より好ましくは５％以下である。 MgO has the effect of lowering the viscosity during glass melting and promoting melting. Moreover, since it has the effect | action which reduces specific gravity and makes a glass plate hard to wrinkle, it can be contained in the structural examples A, B, and C. Further, in order to make the glass have a low coefficient of thermal expansion and good devitrification properties, the content of MgO is preferably 10% or less, more preferably 8% or less in the configuration example A. In Example B, it is preferably 15% or less, more preferably 12% or less, and in Structural Example C, it is preferably 10% or less, more preferably 5% or less.
　ＣａＯは、ガラス原料の溶融を促進し、また粘性又は熱膨張等を調整する成分であるので、構成例Ａ、Ｂ及びＣにおいて含有させることができる。上記の作用を得るためには、構成例Ａにおいては、ＣａＯの含有量は、好ましくは３％以上、より好ましくは５％以上である。また、失透を良好にするためには、構成例Ａにおいては、好ましくは２０％以下、より好ましくは１０％以下であり、構成例Ｂにおいては、好ましくは６％以下であり、より好ましくは４％以下である。 CaO is a component that promotes melting of the glass raw material and adjusts viscosity or thermal expansion, and therefore can be contained in the structural examples A, B, and C. In order to obtain the above action, in the configuration example A, the content of CaO is preferably 3% or more, more preferably 5% or more. In order to improve devitrification, in the configuration example A, it is preferably 20% or less, more preferably 10% or less, and in the configuration example B, preferably 6% or less, more preferably 4% or less.
　ＳｒＯは、熱膨張係数の増大及びガラスの高温粘度を下げる効果がある。かかる効果を得るために、構成例Ａ、Ｂ及びＣにおいて、ＳｒＯを含有させることができる。但し、ガラスの熱膨張係数を低く抑えるため、ＳｒＯの含有量は、構成例Ａ及びＣにおいては、１５％以下とするのが好ましく、１０％以下とするのがより好ましく、構成例Ｂにおいては、５％以下とするのが好ましく、３％以下とするのがより好ましい。 SrO has the effect of increasing the thermal expansion coefficient and lowering the high temperature viscosity of the glass. In order to obtain such an effect, SrO can be contained in the structural examples A, B, and C. However, in order to keep the thermal expansion coefficient of the glass low, the content of SrO is preferably 15% or less in the structural examples A and C, more preferably 10% or less, and in the structural example B It is preferably 5% or less, and more preferably 3% or less.
　ＢａＯは、ＳｒＯ同様に熱膨張係数の増大及びガラスの高温粘度を下げる効果がある。上記の効果を得るためにＢａＯを含有させることができる。但し、ガラスの熱膨張係数を低く抑えるため、構成例Ａ及びＣにおいては、１５％以下とするのが好ましく、１０％以下とするのがより好ましく、構成例Ｂにおいては、５％以下とするのが好ましく、３％以下とするのがより好ましい。 BaO, like SrO, has the effect of increasing the coefficient of thermal expansion and lowering the high temperature viscosity of the glass. In order to obtain the above effect, BaO can be contained. However, in order to keep the thermal expansion coefficient of the glass low, it is preferably 15% or less in Configuration Examples A and C, more preferably 10% or less, and 5% or less in Configuration Example B. Of these, 3% or less is more preferable.
　また、これらアルカリ土類金属酸化物の合計含有量（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）は、熱膨張係数を低く抑え、失透特性を良好なものとし、強度を維持するために、構成例Ａにおいては、好ましくは１０％～３０％、より好ましくは１３％～２７％であり、構成例Ｂにおいては、好ましくは１％～１５％、より好ましくは３％～１０％であり、構成例Ｃにおいては、好ましくは５％～３０％、より好ましくは１０％～２０％である。 Further, the total content of these alkaline earth metal oxides (MgO + CaO + SrO + BaO) is preferably 10 in the configuration example A in order to keep the coefficient of thermal expansion low, to improve the devitrification characteristics, and to maintain the strength. % To 30%, more preferably 13% to 27%. In the configuration example B, preferably 1% to 15%, more preferably 3% to 10%, and in the configuration example C, preferably 5%. % To 30%, more preferably 10% to 20%.
　本実施形態のガラス板１０のガラスのガラス組成においては、ガラスの耐熱性及び表面硬度の向上のために、任意成分としてＺｒＯ２を、構成例Ａ、Ｂ及びＣにおいて、１０％以下、好ましくは５％以下含有させてもよい。１０％以下とすることでガラスが失透しにくくなる。 In the glass composition of the glass plate 10 of the present embodiment, in order to improve the heat resistance and surface hardness of the glass, ZrO 2 is used as an optional component in the structural examples A, B and C, preferably 10% or less, preferably You may make it contain 5% or less. It becomes difficult to devitrify glass by setting it as 10% or less.
　本実施形態のガラス板１０のガラスのガラス組成においては、ガラスの熔解性向上のため、Ｆｅ２Ｏ３を、構成例Ａ、Ｂ及びＣにおいて、５～１００ｐｐｍ含有させてもよい。なお、Ｆｅ２Ｏ３量の好ましい範囲は上述のとおりである。 In the glass composition of the glass plate 10 of the present embodiment, 5 to 100 ppm of Fe 2 O 3 may be contained in the structural examples A, B, and C in order to improve the meltability of the glass. In addition, the preferable range of the amount of Fe 2 O 3 is as described above.
　また、本実施形態のガラス板１０のガラスは、清澄剤としてＳＯ３を含有してもよい。この場合、ＳＯ３含有量は、質量百分率表示で０％超、０．５％以下が好ましい。０．４％以下がより好ましく、０．３％以下がさらに好ましく、０．２５％以下であることがさらに好ましい。 The glass of the glass plate 10 of the present embodiment may contain SO 3 as a fining agent. In this case, the SO 3 content is preferably more than 0% and 0.5% or less in terms of mass percentage. 0.4% or less is more preferable, 0.3% or less is more preferable, and 0.25% or less is further preferable.
　また、本実施形態のガラス板１０のガラスは、酸化剤及び清澄剤としてＳｂ２Ｏ３、ＳｎＯ２及びＡｓ２Ｏ３のうちの一つ以上を含有してもよい。この場合、Ｓｂ２Ｏ３、ＳｎＯ２またはＡｓ２Ｏ３の含有量は、質量百分率表示で０～０．５％が好ましい。０．２％以下がより好ましく、０．１％以下がさらに好ましく、実質的に含有しないことがさらに好ましい。 Moreover, the glass of the glass plate 10 of this embodiment may contain one or more of Sb 2 O 3 , SnO 2 and As 2 O 3 as an oxidizing agent and a fining agent. In this case, the content of Sb 2 O 3 , SnO 2 or As 2 O 3 is preferably 0 to 0.5% in terms of mass percentage. 0.2% or less is more preferable, 0.1% or less is more preferable, and it is further more preferable not to contain substantially.
　ただし、Ｓｂ２Ｏ３、ＳｎＯ２及びＡｓ２Ｏ３は、ガラスの酸化剤として作用するため、ガラスのＦｅ２＋の量を調節する目的により上記範囲内で添加してもよい。ただし、環境面からはＡｓ２Ｏ３を実質的に含有しないことが好ましい。 However, since Sb 2 O 3 , SnO 2 and As 2 O 3 act as an oxidizing agent for glass, they may be added within the above range for the purpose of adjusting the amount of Fe 2+ in the glass. However, from the environmental aspect, it is preferable that As 2 O 3 is not substantially contained.
　また、本実施形態のガラス板１０のガラスは、ＮｉＯを含有してもよい。ＮｉＯを含有する場合、ＮｉＯは、着色成分としても機能するので、ＮｉＯの含有量は、上記したガラス組成の合量に対し、１０ｐｐｍ以下とするのが好ましい。特に、ＮｉＯは、波長４００～７００ｎｍにおけるガラス板の内部透過率を低下させないという観点から、１．０ｐｐｍ以下とするのが好ましく、０．５ｐｐｍ以下とすることがより好ましい。 Moreover, the glass of the glass plate 10 of this embodiment may contain NiO. When NiO is contained, since NiO functions also as a coloring component, the content of NiO is preferably 10 ppm or less with respect to the total amount of the glass composition described above. In particular, NiO is preferably 1.0 ppm or less, and more preferably 0.5 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
　本実施形態のガラス板１０のガラスは、Ｃｒ２Ｏ３を含有してもよい。Ｃｒ２Ｏ３を含有する場合、Ｃｒ２Ｏ３は、着色成分としても機能するので、Ｃｒ２Ｏ３の含有量は、上記したガラス組成の合量に対し、１０ｐｐｍ以下とするのが好ましい。特に、Ｃｒ２Ｏ３は、波長４００～７００ｎｍにおけるガラス板の内部透過率を低下させないという観点から、１．０ｐｐｍ以下とするのがより好ましく、０．５ｐｐｍ以下とすることがさらに好ましい。 The glass of the glass plate 10 of this embodiment may contain Cr 2 O 3 . When Cr 2 O 3 is contained, Cr 2 O 3 also functions as a coloring component. Therefore, the content of Cr 2 O 3 is preferably 10 ppm or less with respect to the total amount of the glass composition described above. In particular, Cr 2 O 3 is more preferably 1.0 ppm or less, and even more preferably 0.5 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
　本実施形態のガラス板１０のガラスは、ＭｎＯ２を含有してもよい。ＭｎＯ２を含有する場合、ＭｎＯ２は、可視光を吸収する成分としても機能するので、ＭｎＯ２の含有量は、上記したガラス組成の合量に対し、５０ｐｐｍ以下とするのが好ましい。特に、ＭｎＯ２は、波長４００～７００ｎｍにおけるガラス板の内部透過率を低下させないという観点から、１０ｐｐｍ以下とするのがより好ましい。 The glass of the glass plate 10 of this embodiment may contain MnO 2 . When MnO 2 is contained, since MnO 2 functions also as a component that absorbs visible light, the content of MnO 2 is preferably 50 ppm or less with respect to the total amount of the glass composition described above. In particular, MnO 2 is more preferably 10 ppm or less from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
　本実施形態のガラス板１０のガラスは、ＴｉＯ２を含んでいてもよい。ＴｉＯ２を含有する場合、ＴｉＯ２は、可視光を吸収する成分としても機能するので、ＴｉＯ２の含有量は、上記したガラス組成の合量に対し、１０００ｐｐｍ以下とするのが好ましい。ＴｉＯ２は、波長４００～７００ｎｍにおけるガラス板の内部透過率を低下させないという観点から、含有量を５００ｐｐｍ以下とすることがより好ましく、１００ｐｐｍ以下とすることが特に好ましい。 Glass of the glass plate 10 of the present embodiment may include TiO 2. When TiO 2 is contained, TiO 2 also functions as a component that absorbs visible light. Therefore, the content of TiO 2 is preferably 1000 ppm or less with respect to the total amount of the glass composition described above. The content of TiO 2 is more preferably 500 ppm or less, and particularly preferably 100 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
　本実施形態のガラス板１０のガラスは、ＣｅＯ２を含んでいてもよい。ＣｅＯ２には鉄のレドックスを下げる効果があり、全鉄量に対するＦｅ２＋量の比率を小さくすることができる。一方で、鉄のレドックスを３％未満に下がることを抑制するためにも、ＣｅＯ２の含有量は、上記したガラス組成の合量に対し、１０００ｐｐｍ以下とするのが好ましい。また、ＣｅＯ２の含有量は、５００ｐｐｍ以下とするのがより好ましく、４００ｐｐｍ以下とするのがさらに好ましく、３００ｐｐｍ以下とするのが特に好ましく、２５０ｐｐｍ以下とするのが最も好ましい。 Glass of the glass plate 10 of the present embodiment may include CeO 2. CeO 2 has the effect of reducing the redox of iron, and the ratio of the Fe 2+ amount to the total iron amount can be reduced. On the other hand, in order to suppress the iron redox from decreasing to less than 3%, the CeO 2 content is preferably 1000 ppm or less with respect to the total amount of the glass composition described above. The CeO 2 content is more preferably 500 ppm or less, further preferably 400 ppm or less, particularly preferably 300 ppm or less, and most preferably 250 ppm or less.
　本実施形態のガラス板１０のガラスは、ＣｏＯ、Ｖ２Ｏ５及びＣｕＯからなる群より選ばれる少なくとも１種の成分を含んでいてもよい。これらの成分を含有する場合、可視光を吸収する成分としても機能するので、前記成分の含有量は、上記したガラス組成の合量に対し、１０ｐｐｍ以下とするのが好ましい。特に、これら成分は、波長４００～７００ｎｍにおけるガラス板の内部透過率を低下させないように、実質的に含有しないことが好ましい。 The glass of the glass plate 10 of this embodiment may include at least one component selected from the group consisting of CoO, V 2 O 5 and CuO. When these components are contained, they also function as components that absorb visible light, and therefore the content of the components is preferably 10 ppm or less with respect to the total amount of the glass composition described above. In particular, it is preferable that these components are not substantially contained so as not to lower the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.
　本発明のガラス板１０は、その内部に少なくとも１つ以上の泡が存在するが、以下に示す手順で輝度評価を実施した際に、輝度の均一性が高く、エッジライト方式の面状発光装置の導光板として使用するのに好適である。 The glass plate 10 of the present invention has at least one or more bubbles in the inside thereof. When the luminance evaluation is performed according to the following procedure, the luminance uniformity is high, and the edge light type planar light emitting device. It is suitable for use as a light guide plate.
　本発明のガラス板１０の輝度評価では、第１主表面１１に面するように反射部材及び散乱部材を配置する。図１に示す導光板ユニット１００を参照すると、導光板２００が本発明のガラス板１０であり、導光板２００の光反射面となる、本発明のガラス板１０の第１主表面１１と対向するように反射部材３００が配置される。 In the luminance evaluation of the glass plate 10 of the present invention, a reflecting member and a scattering member are arranged so as to face the first main surface 11. Referring to the light guide plate unit 100 shown in FIG. 1, the light guide plate 200 is the glass plate 10 of the present invention, and is opposed to the first main surface 11 of the glass plate 10 of the present invention, which serves as a light reflecting surface of the light guide plate 200. Thus, the reflection member 300 is arranged.
　本発明のガラス板１０と、反射部材３００と、の間に位置するように、本発明のガラス板１０の第１主表面１１に、ドットパターン状に所定の間隔で散乱部材４００が形成される。散乱部材については、エッジライト方式の面状発光装置の導光板としての機能を発揮できる限り、他の構成であってもよい。 Scattering members 400 are formed at predetermined intervals in a dot pattern on the first main surface 11 of the glass plate 10 of the present invention so as to be positioned between the glass plate 10 of the present invention and the reflecting member 300. . The scattering member may have another configuration as long as it can function as a light guide plate of the edge light type planar light emitting device.
　この状態で、本発明のガラス板１０の４つの端面１３のうちの一つを基準端面とし、該基準端面に面するように光源を配置して、該光源から該基準端面に向けて可視光の波長域の光を照射する。 In this state, one of the four end faces 13 of the glass plate 10 of the present invention is used as a reference end face, a light source is disposed so as to face the reference end face, and visible light is directed from the light source toward the reference end face. Irradiate light in the wavelength range of.
　光源からの光は、導光板２００の光出射面となる、本発明のガラス板１０の第２主表面１２から出射される。この出射光の輝度を測定した際に、本発明のガラス板１０は、最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）と、の比Ｌｍａｘ／Ｌａｖｅが、１≦Ｌｍａｘ／Ｌａｖｅ≦１．１を満足するため、輝度の均一性が高く、エッジライト方式の面状発光装置の導光板として使用するのに好適である。 The light from the light source is emitted from the second main surface 12 of the glass plate 10 of the present invention, which becomes the light emission surface of the light guide plate 200. When the luminance of the emitted light is measured, the glass plate 10 of the present invention has a ratio L max / L ave between the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ). However, since 1 ≦ L max / L ave ≦ 1.1 is satisfied, the luminance uniformity is high, and it is suitable for use as a light guide plate of an edge light type planar light emitting device.
　本発明のガラス板１０は、上記の手順で測定される平均輝度Ｌａｖｅが１０００ｃｄ／ｍ２以上であることが好ましく、１２００ｃｄ／ｍ２以上であることがより好ましく、１５００ｃｄ／ｍ２以上であることがさらに好ましい。平均輝度Ｌａｖｅが１０００ｃｄ／ｍ２以上であることにより、ディスプレイ映像の視認性が明るい環境下で向上させる事が可能である。 A glass plate 10 of the present invention preferably has an average luminance L ave measured by the above procedure is 1000 cd / m 2 or more, more preferably 1200 cd / m 2 or more, is 1500 cd / m 2 or more More preferably. When the average luminance L ave is 1000 cd / m 2 or more, the visibility of the display image can be improved in a bright environment.
　実施例では、以下の手順でガラス板の輝度測定を実施した。
（輝度測定）
　内部に少なくとも１つ以上の泡が存在するガラス板の一方の主表面に、拡散インキをドットパターン状に印刷して、一方の主表面に散乱部材を形成されたガラス導光板を作成した。このガラス板の寸法は、４８５ｍｍ×２８４ｍｍ×ｔ２ｍｍであった。 In the examples, the luminance of the glass plate was measured according to the following procedure.
(Brightness measurement)
Diffusion ink was printed in a dot pattern on one main surface of a glass plate having at least one bubble inside, and a glass light guide plate having a scattering member formed on one main surface was produced. The dimension of this glass plate was 485 mm x 284 mm x t2 mm.
　また、波長４００～７００ｎｍの範囲の光の吸収係数を紫外可視近赤外分光光度計（日立ハイテクサイエンス社製　ＵＨ４１５０）を用いて測定したところ、波長５５０ｎｍの光の吸収係数は０．０４ｍ－１であった。また、波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘは０．２４ｍ－１、最小値αｍｉｎは０．０４ｍ－１であり、（αｍａｘ／αｍｉｎ）は６であった。 Further, when the absorption coefficient of light in the wavelength range of 400 to 700 nm was measured using an ultraviolet-visible near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science Co., Ltd.), the absorption coefficient of light having a wavelength of 550 nm was 0.04 m −1. Met. The maximum value α max of the light absorption coefficient in the wavelength range of 400 to 700 nm was 0.24 m −1 , the minimum value α min was 0.04 m −1 , and (α max / α min ) was 6. .
　上記の手順で得られたガラス導光板を、液晶ディスプレイ（ＬＧ社製　型番　２２ＥＮ４３ＶＢ）に、同液晶ディスプレイのアクリル導光板と入れ替えて配置し、暗室で白画面を表示し、ＥｙｅＳｃａｌｅ－３Ｗ（アイシステム社製）を用い、測定距離３ｍで輝度を測定した。測定された最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）を下記表１に示す。 The glass light guide plate obtained by the above procedure is placed on a liquid crystal display (Model No. 22EN43VB, manufactured by LG), replacing the acrylic light guide plate of the liquid crystal display, and a white screen is displayed in a dark room. EyeScale-3W (eye system) The brightness was measured at a measurement distance of 3 m. Table 1 below shows the measured maximum luminance L max (cd / m 2 ) and average luminance L ave (cd / m 2 ).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、実施例１～４のガラス板は、上記の手順で実施した輝度測定における最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）と、の比Ｌｍａｘ／Ｌａｖｅが、１≦Ｌｍａｘ／Ｌａｖｅ≦１．１を満足するため、輝度の均一性が高く、エッジライト方式の面状発光装置の導光板として使用するのに好適であることがわかった。 As shown in Table 1, the glass plates of Examples 1 to 4 have the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ) in the luminance measurement performed in the above procedure, The ratio L max / L ave satisfies 1 ≦ L max / L ave ≦ 1.1, so that the luminance uniformity is high and suitable for use as a light guide plate of an edge light type planar light emitting device. I found out.
　また、比較例１～３のガラス板は、最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）と、の比Ｌｍａｘ／Ｌａｖｅが、１．１＜Ｌｍａｘ／Ｌａｖｅであるため、輝度の均一性が低かった。 In the glass plates of Comparative Examples 1 to 3, the ratio L max / L ave between the maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m 2 ) is 1.1 <L. Since max / L ave , the luminance uniformity was low.
　本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更および変形が可能であることは、当業者にとって明らかである。なお本出願は、２０１４年８月２８日付で出願された日本特許出願（特願２０１４－１７３９６８）に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on August 28, 2014 (Japanese Patent Application No. 2014-173968), which is incorporated by reference in its entirety.
　１０：ガラス板
　１１：第１主表面
　１２：第２主表面
　１３：端面
　２０：ガラス
　３０：泡
　１００：導光板ユニット
　２００：導光板
　３００：反射部材
　４００：散乱部材 DESCRIPTION OF SYMBOLS 10: Glass plate 11: 1st main surface 12: 2nd main surface 13: End surface 20: Glass 30: Foam 100: Light guide plate unit 200: Light guide plate 300: Reflective member 400: Scattering member

Claims (4)

  1. 　第１主表面、前記第１主表面に対向する第２主表面、並びに、前記第１主表面および前記第２主表面を接続する端面からなり、前記第１主表面および前記第２主表面を持つガラス板において、
    　前記ガラス板は、波長５５０ｎｍの光の吸収係数が１ｍ－１以下であり、波長４００～７８０ｎｍの範囲の光の吸収係数の最大値αｍａｘ（ｍ－１）と、最小値αｍｉｎ（ｍ－１）と、の比（αｍａｘ／αｍｉｎ）が１０以下であり、前記ガラス板の内部には少なくとも１つ以上の泡が存在し、
    　前記第１主表面に面するように反射部材及び散乱部材を配置し、前記端面のうちの一つを基準端面とするとき、前記基準端面に面するように光源を配置して、前記光源から前記基準端面に向けて可視光の波長域の光を照射した際の、前記第２主表面からの出射光における、最大輝度Ｌｍａｘ（ｃｄ／ｍ２）と、平均輝度Ｌａｖｅ（ｃｄ／ｍ２）と、の比Ｌｍａｘ／Ｌａｖｅが、１≦Ｌｍａｘ／Ｌａｖｅ≦１．１を満足することを特徴とするガラス板。     A first main surface, a second main surface facing the first main surface, and an end surface connecting the first main surface and the second main surface, wherein the first main surface and the second main surface are In the glass plate you have,
    The glass plate has a light absorption coefficient of 1 m −1 or less at a wavelength of 550 nm, a maximum value α max (m −1 ) of light absorption coefficient in a wavelength range of 400 to 780 nm, and a minimum value α min (m − 1 ) and a ratio (α max / α min ) of 10 or less, and at least one or more bubbles are present inside the glass plate,
    When a reflecting member and a scattering member are disposed so as to face the first main surface, and one of the end surfaces is a reference end surface, a light source is disposed so as to face the reference end surface, The maximum luminance L max (cd / m 2 ) and the average luminance L ave (cd / m) in the light emitted from the second main surface when light in the visible wavelength range is irradiated toward the reference end face. 2 ) and the ratio L max / L ave satisfies 1 ≦ L max / L ave ≦ 1.1.
  2. 　波長４００～７００ｎｍの範囲の光の吸収係数の最大値αｍａｘが１ｍ－１以下である請求項１に記載のガラス板。 The glass plate according to claim 1, wherein the maximum value α max of the light absorption coefficient in the wavelength range of 400 to 700 nm is 1 m -1 or less.
  3. 　前記第１主表面および前記第２主表面が実質的に矩形であり、少なくとも１辺の長さが２００ｍｍ以上であり、前記ガラス板の板厚が０．５～１０ｍｍであり、前記ガラス板の板厚の公差が±０．１ｍｍ以内である請求項１または２に記載のガラス板。 The first main surface and the second main surface are substantially rectangular, the length of at least one side is 200 mm or more, the plate thickness of the glass plate is 0.5 to 10 mm, The glass plate according to claim 1 or 2, wherein a tolerance of the plate thickness is within ± 0.1 mm.
  4. 　前記第２主表面からの出射光における、平均輝度Ｌａｖｅが１０００ｃｄ／ｍ２以上である、請求項１～３のいずれか１項に記載のガラス板。 The glass plate according to any one of claims 1 to 3, wherein an average luminance L ave in the light emitted from the second main surface is 1000 cd / m 2 or more.
PCT/JP2015/073905 2014-08-28 2015-08-25 Glass sheet WO2016031830A1 (en)

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JP2012124000A (en) * 2010-12-08 2012-06-28 Konica Minolta Advanced Layers Inc Film-like surface light source and liquid crystal display using this
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WO2005122116A1 (en) * 2004-06-11 2005-12-22 Nippon Electric Glass Co., Ltd. Method for sorting plate glass for flat panel display, plate glass for flat panel display and method for manufacturing the same
WO2006112415A1 (en) * 2005-04-15 2006-10-26 Asahi Glass Company, Limited Method for reducing diameter of bubble existing inside of glass plate
JP2009533808A (en) * 2006-04-13 2009-09-17 サン−ゴバン グラス フランス Luminescent panel
JP2011175102A (en) * 2010-02-24 2011-09-08 Sony Corp Optical sheet stack body, illuminating device and display device
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Publication number Priority date Publication date Assignee Title
US11161769B2 (en) 2016-09-16 2021-11-02 Corning Incorporated High transmission glasses with alkaline earth oxides as a modifier

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