JP2016210665A - Glass sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To add colorless and transparent image even when visually recognizing from either direction of a main surface side and a terminal surface side.SOLUTION: When taking a sample having rectangle with two sides having length of 5 mm and 50 mm respectively and setting one of 2 cross sections with length of 5 mm of the cross sections of the sample as a first cross section and another of the 2 cross sections with length of 50 mm as a second cross sections in a glass sheet, color difference on a CIE1976(L,a,b) color system between transmission spectrum in a normal direction of the first cross section and transmission spectrum in a normal direction of the second cross section is 1.5 or less and L value on the CIE1976(L,a,b) color system of the transmission spectrum with optical distance of 50 mm measured in the normal direction of the first cross section is 95.9 or more and a value of (a+b)is 1.8 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a glass plate, and particularly to a glass plate having a high transmittance.

  Glass plates are used in a variety of applications such as building and vehicle windows, building interiors, furniture, and display cases. Some of these uses require aesthetics and design. In particular, in recent years, the demand for improvement in design has been increasing.

  Here, when considering a glass plate having two main surfaces and one or a plurality of end faces connecting the two main surfaces, in a conventional glass plate, the impression obtained from the glass plate may change depending on the viewing direction. is there.

  In patent document 1, the design property is made high by adding the coloring component which is easy to control so that the color when it sees from the end surface direction of a glass plate does not vary by the influence of a trace amount component. Patent Document 2 proposes a highly transparent glass plate having a pure and bright blue sky color for furniture such as a table top or a shelf. Patent Document 3 proposes a group of highly transparent glass plates that give a pleasant appearance compatible with the surrounding wooden objects and have bright attractive edge colors as glass parts for furniture and other special applications. Yes.

Although these glass plates are excellent in transparency as compared with ordinary glass plates, they are characterized by giving an impressive appearance due to coloring when viewed from the end face direction.
Japanese Patent No. 4228842 Japanese Patent Publication No. 7-29810 Japanese Patent Publication No. 8-715

  As mentioned above, in the conventional glass plate used for architectural purposes, even when the glass plate looks colorless and transparent when viewed from the main surface side, when the glass plate is viewed from the end surface side, You may feel a color, such as green or yellow. The impression of the color received from the end surface of such a glass plate can become a factor which reduces the designability of a glass plate.

  Furthermore, there is a demand for the realization of a glass plate having a more transparent impression with extremely reduced coloring when viewed from the end face direction (hereinafter also referred to as the normal direction of the end face).

  When such a glass plate is viewed from the end surface direction, since the visibility in the end surface direction is higher than that of the conventional glass plate, the inhomogeneity of the refractive index distribution inside the plate is easily noticeable, and the end surface There has been a concern that problems may arise in terms of design, such as distortion of an image viewed from the direction.

  In addition to these issues, there is a need for the realization of highly transparent glass plates that do not feel uncomfortable even when used in combination with acrylic, which has been widely used in interiors, furniture, furniture, etc. in recent years. Yes. For applications where acrylic is widely used, the use of high-transmission glass plates in the past has led to increased thickness from the standpoint of rigidity (for example, for shelves and display cases). In addition to being able to give a more refined impression by reducing the thickness of the shelf board), it is possible to realize an unprecedented novel design by using a combination of glass and acrylic. Because. In these applications, in order to use in combination with other acrylic members, it is necessary to bring the transparency and color of the glass plate as close as possible to the acrylic plate.

  The present invention has been made in view of such a background. An object of the present invention is to provide a glass plate that gives a colorless and transparent impression and is substantially free from image distortion when viewed from either the main surface side or the end surface side.

In the present invention, a glass plate made of a multi-component oxide glass having first and second main surfaces and at least one end surface including the first end surfaces connecting the main surfaces. ,
The total amount of iron converted to Fe ₂ O ₃ is 1 mass ppm or more and 80 mass ppm or less, Fe ²⁺ converted to Fe ₂ O ₃ is 0.1 mass ppm or more and 10 mass ppm or less,
Metal ions selected from the group consisting of Ni, Mn, Cr, Co, V and Se total 0.1 to 30 ppm by mass,
By cutting the glass plate in a direction perpendicular to the first main surface, a rectangular sample having two side lengths of 5 mm and 50 mm is collected from the central portion of the glass plate, and the sample When one of the two cut surfaces having a length of 5 mm is referred to as a first cut surface and one of the two cut surfaces having a length of 50 mm is referred to as a second cut surface. ,
In the sample A in a state where the four cut surfaces are polished so that the arithmetic average roughness Ra is 0.1 μm or less,
A transmission spectrum T1 having an optical path length of 50 mm measured in the normal direction of the first cut surface at the first cut surface and a normal spectrum direction of the second cut surface at the second cut surface. The value of the color difference ΔE ^* _ab on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated by the transmission spectrum T2 having a path length of 5 mm is 1.5 or less, The value of L ^* on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated from the transmission spectrum T1 is 95.9 or more, and (a ^{* 2} + b ^{* 2} ) ⁰ A glass plate is provided in which the value of ^.5 is 1.8 or less.

  In the present invention, it is possible to provide a glass plate that gives a colorless and transparent impression and is substantially free from image distortion even when viewed from either the main surface side or the end surface side.

It is the figure which showed schematically the structure of the glass plate by one Embodiment of this invention. It is the figure which showed typically the structure of the apparatus used when evaluating the rectilinear advance of the light in a glass plate. It is the figure which showed the schematic flow of an example of the manufacturing method of the glass plate by one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In FIG. 1, the structure of the glass plate by one Embodiment of this invention is shown roughly.

  As shown in FIG. 1, the glass plate 100 by one Embodiment of this invention has 1st and 2nd main surface 120A, 120B, and four end surface 130A-130D.

  In the example of FIG. 1, the glass plate 100 has a substantially rectangular shape. However, this is merely an example, and the glass plate may have other forms, for example, a disk shape or a block shape. In the case of a disk-shaped glass plate, there is one “end face”. In the case of a block-shaped glass plate, the “main surface” is defined as two opposing surfaces having the maximum surface area.

  Here, when a conventional transparent glass plate is used as the glass plate 100, the impression obtained from the glass plate may change depending on the viewing direction. For example, in FIG. 1, the glass plate is viewed from the X direction, that is, the normal direction of the main surface 120A (hereinafter referred to as the first direction F1), and the Y direction, that is, the normal line of the end surface 130A or the end surface 130C. There are cases where the impression received from the glass plate is different depending on the direction (hereinafter referred to as the second direction F2). Similarly, the impression received from the glass plate when viewed from the first direction F1 and when viewed from the Z direction, that is, the normal direction of the end surface 130B or the end surface 130D (hereinafter referred to as the third direction F3). May be different.

  For example, when a glass plate is viewed from the first direction F1, it looks colorless and transparent, but when viewed from the second direction F2 or the third direction F3, a color such as green or yellow is felt. There is. Such a direction dependency of the impression to be felt and the impression of the color received from the end face of the glass plate may be a factor of deteriorating the design of the glass plate.

On the other hand, in one embodiment of the present invention, a multi-component oxidation having the first and second main surfaces and at least one end surface that connects the main surfaces and includes the first end surface. It is a glass plate made of physical glass,
The total amount of iron converted to Fe ₂ O ₃ is 1 mass ppm or more and 80 mass ppm or less, Fe ²⁺ converted to Fe ₂ O ₃ is 0.1 mass ppm or more and 10 mass ppm or less,
Metal ions selected from the group consisting of Ni, Mn, Cr, Co, V and Se total 0.1 to 30 ppm by mass,
By cutting the glass plate in a direction perpendicular to the first main surface, a rectangular sample having two side lengths of 5 mm and 50 mm is collected from the central portion of the glass plate, and the sample When one of the two cut surfaces having a length of 5 mm is referred to as a first cut surface and one of the two cut surfaces having a length of 50 mm is referred to as a second cut surface. ,
In the sample A in a state where the four cut surfaces are polished so that the arithmetic average roughness Ra is 0.1 μm or less,
A transmission spectrum T1 having an optical path length of 50 mm measured in the normal direction of the first cut surface at the first cut surface and a normal spectrum direction of the second cut surface at the second cut surface. The value of the color difference ΔE ^* _ab on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated by the transmission spectrum T2 having a path length of 5 mm is 1.5 or less, The value of L ^* on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated from the transmission spectrum T1 is 95.9 or more, and (a ^{* 2} + b ^{* 2} ) ⁰ A glass plate is provided in which the value of ^.5 is 1.8 or less.

  The multicomponent oxide glass means an oxide glass excluding silica glass composed only of silica.

  The main factor of light absorption of the glass plate is iron ions contained as impurities. Iron is unavoidably contained as a raw material for industrially produced glass, and it is inevitable that iron is mixed into the glass.

In the glass plate 100 according to an exemplary embodiment of the present invention, the total iron oxide in terms of Fe ₂ O ₃ content (hereinafter, also referred to as t-Fe ₂ O ₃₎ is to realize a very high transmittance over the entire visible range Therefore, it is set to 80 mass ppm or less. The content of t-Fe ₂ O ₃ is more preferably 60 ppm by mass or less, further preferably 50 ppm by mass or less, particularly preferably 40 ppm by mass or less, and most preferably 35 ppm by mass or less. .

On the other hand, the amount of t-Fe ₂ O ₃ of the glass plate 100 according to an embodiment of the present invention is 1 ppm by mass or more. If it is less than 1 mass ppm, it is difficult to improve the solubility of the glass during the production of multi-component oxide glass, and it is difficult to mass-produce at low cost. Moreover, it is difficult to obtain raw materials. Preferably it is 5 mass ppm or more, More preferably, it is 8 mass ppm or more, More preferably, it is 10 mass ppm or more. The amount of t-Fe ₂ O ₃ in the glass can be adjusted by the amount of the iron component added during glass production.

In the present invention, the total iron oxide amount in the glass plate 100 is expressed as the amount of Fe ₂ O ₃ , but usually 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 (hereinafter, these are collectively referred to as “iron component”). Although iron component has an absorption in the visible light region, the absorption coefficient of the ^{Fe 2+ (11cm -1 Mol} -1), since an order of magnitude greater than the absorption coefficient of the ^{Fe 3+ (0.96cm -1 Mol -1)} , visible The internal transmittance of the light region is further reduced. Therefore, it is preferable that the Fe ²⁺ content is small in order to increase the internal transmittance in the visible light region.

In the glass plate 100, the content of divalent iron (Fe ²⁺ ) converted to Fe ₂ O ₃ in terms of mass ppm is suppressed to 10 mass ppm or less. Preferably it is 8.0 mass ppm or less, More preferably, it is 6.0 mass ppm or less, Especially preferably, it is 4.0 mass ppm or less, Most preferably, it is 3.5 mass ppm or less.

  Thus, in the glass plate by one Embodiment of this invention, absorption of the light of the specific wavelength by an iron component can be suppressed significantly by controlling the quantity of an iron component.

When the total iron oxide content contained in the glass plate is suppressed to 80 ppm or less and the content of divalent iron (Fe ²⁺ ) converted to Fe ₂ O ₃ in terms of mass ppm is suppressed to 10 mass ppm or less, It may be difficult to manufacture the glass plate. In particular, the inventors have clarified that it is difficult to increase the homogeneity in the kiln during melting as compared with the conventional glass.

That is, molten glass from which iron components, particularly Fe ²⁺ are excessively excluded, has a characteristic that it is difficult to absorb light, particularly infrared light. For this reason, in order to heat such molten glass, it is necessary to administer a great deal of energy. As a result, there is a concern that the energy efficiency in the manufacturing process is reduced to an unrealistic level. Moreover, in such a heated state, there is a concern that the composition changes between the upper part and the bottom part of the molten glass and the composition of the finally obtained glass plate becomes non-uniform. Furthermore, there is a concern that the production facility may be damaged or deteriorated during operation at such a high temperature. Conversely, if the heating state is suppressed to the equivalent of ordinary glass, the melting of the glass will not be promoted and foam defects will increase, and the molten glass will become inhomogeneous due to its low viscosity. There is.

  However, the glass plate according to an embodiment of the present invention has a total content of metal ions selected from the group consisting of Ni, Mn, Cr, Co, V, and Se in order to cope with such problems. It is controlled to be 1 mass ppm or more.

These metal ions have the property of absorbing light in the range from the ultraviolet region to the near infrared region. For this reason, when these transition metal ions are contained in the molten glass, heating is relatively easy even when the iron component, particularly Fe ²⁺ is excessively excluded, and the above-described problems are reduced. The

  These transition metal ions also function as a coloring component of the glass. Therefore, by adjusting the amount of these transition metal ions, the light absorption spectrum in the wavelength range of 400 to 700 nm is controlled by intentionally causing weak light absorption in a wavelength region other than light absorption by the iron component. can do. Thereby, compared with the glass plate obtained by simply reducing the iron component, the transmitted color can be kept transparent even when the optical path length is increased.

  On the other hand, when many of these transition metal ions are contained in the glass raw material, the transparency of the finally obtained glass plate is lowered. However, in the glass plate according to one embodiment of the present invention, the total sum of these transition metal ions is controlled to be no more than 30 ppm by mass. For this reason, in one Embodiment of this invention, it becomes possible to manufacture a homogeneous glass plate by a realistic process, without having a bad influence on transparency. Among these transition metal ions, the total sum of Ni, Cr, Co, V, and Se that is particularly likely to adversely affect transparency is preferably 5.0 ppm by mass or less, more preferably 3.0 ppm by mass or less. Yes, particularly preferably 2.0 ppm by mass or less, and most preferably 1.5 ppm by mass or less.

  Due to the above features, the glass plate 100 according to an embodiment of the present invention has high transparency and can significantly suppress the problem that light of a specific wavelength is selectively absorbed. Thereby, even if it is a case where the glass plate 100 is visually recognized from the 2nd direction F2 or the 3rd direction F3, a colorless and transparent impression can be obtained.

Moreover, in one Embodiment of this invention, the length of two sides is 5 mm and 50 mm from the center part of the glass plate 100 by cut | disconnecting the glass plate 100 in the direction perpendicular | vertical to a 1st main surface, respectively. A rectangular sample is taken, and one of the two cut surfaces having a length of 5 mm is referred to as a first cut surface, and one of the two cut surfaces having a length of 50 mm is selected from the cut surfaces of the sample. Is called the second cut surface,
In the sample A in a state where the four cut surfaces are polished so that the arithmetic average roughness Ra is 0.1 μm or less,
A transmission spectrum T1 having an optical path length of 50 mm measured in the normal direction of the first cut surface at the first cut surface and a normal spectrum direction of the second cut surface at the second cut surface. The value of the color difference ΔE ^* _ab on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source, calculated from the transmission spectrum T2 having an optical path length of 5 mm, is 1.5 or less, and the transmission spectrum The value of L ^* on the CIE 1976 (L ^* , a ^* , b ^* ) color system calculated from T1 is 95.9 or more, and (a ^{* 2} + b ^{* 2} ) ^0.5 The value of is 1.8 or less.

Here, the value of the color difference ΔE ^* _ab between the first main surface and the first cut surface is calculated from T1 and T2, respectively, and the two-color coordinates P _T1 on the (L ^* , a ^* , b ^* ) space. (L ₁ , a ₁ , b ₁ ), P _T2 (L ₂ , a ₂ , b ₂ ) Euclidean distance,
ΔE ^* _ab = ((L ₂ −L ₁ ) ² + (a ₂ −a ₁ ) ² + (b ₂ −b ₁ ) ² ) ^0.5
Can be calculated with Preferably it is 1.25 or less, More preferably, it is 1.0 or less, More preferably, it is 0.75 or less, Especially preferably, it is 0.6 or less, Most preferably, it is 0.5 or less.

Further, the value of L ^* in the first cut surface is preferably 96.0 or more, more preferably 96.1 or more, particularly preferably 96.2 or more, and most preferably 96.3. That's it. (A ^{* 2} + b ^{* 2} ) A value of ^0.5 represents saturation, preferably 1.6 or less, more preferably 1.4 or less, and even more preferably 1.25 or less. Particularly preferred is 1.0 or less, and most preferred is 0.8 or less.

Here, the CIE 1976 (L ^* , a ^* , b ^* ) color system used in the present application is based on JIS Z 8781-4 (2013).

  In such a glass plate 100, a colorless and transparent impression can be obtained when viewed from any of the first direction F1 to the third direction F3. For this reason, the difference of the impression by a visual recognition direction can be suppressed.

  Due to these effects, the design of the glass plate 100 according to one embodiment of the present invention can be significantly improved.

(About other characteristics of the glass plate by one Embodiment of this invention)
Hereinafter, other features of the glass plate according to the embodiment of the present invention will be briefly described. Here, for the sake of clarity, the reference numerals shown in FIG. 1 are used when representing each part of the glass plate.

(Homogeneity in the direction of the end face of the glass plate)
The glass plate by one Embodiment of this invention has the characteristics that the distortion of the image at the time of visually recognizing from the end surface direction of this glass plate is suppressed. Hereinafter, the characteristics will be described.

  The fact that the distortion of the image is suppressed means that the straightness of light in the direction of the end face of the glass plate is excellent. In the present application, the straight traveling property of light can be evaluated using an apparatus as shown in FIG.

In FIG. 2, the structure of the apparatus used when evaluating the rectilinear advance of the light in a glass plate is shown typically. As shown in FIG. 2, the apparatus 200 includes a laser light source 210 and a screen 220. The distance d ₁ from the laser light source 210 to the screen 220 is 160 mm.

  When evaluating the straightness of light in the glass plate using the apparatus 200, first, an evaluation sample is prepared.

  A sample is obtained by cutting a glass plate to be measured in a direction perpendicular to the main surface and taking a dimension of 5 mm in length and 50 mm in width from a substantially central portion of the glass plate.

  In addition, when the main surface and cut surface of the obtained sample are not smooth, the arithmetic mean roughness Ra of each of the two main surfaces of the sample and the two cut surfaces facing the sample is 0.1 μm or less. A sample 230 is prepared by polishing. Note that the sample 230 may be the sample A described above.

Then, without setting sample 230 into the apparatus 200, laser light is applied toward the laser light source 210 on the screen 220, to measure the area _{S 0} of the spot 240 formed on the screen.

Next, the sample 230 is disposed between the laser light source 210 and the screen 220, and the same measurement is performed. In this case, the sample 230 is arranged so that the laser beam is irradiated on the substantially central portion of one of the two cut surfaces having a length of 5 mm (hereinafter referred to as “irradiation surface”). The distance _{d 2} from the laser light source 210 to the irradiation surface of the sample 230 is 40 mm. The area of the spot 240 formed on the screen 220 to _{S 1.}

  As a laser beam to be used, a commercially available red laser pointer (wavelength 635 nm, etc.) is mentioned as an example. In the case where the beam diameter of the laser light is larger than the thickness of the sample 230, a slit may be appropriately provided between the laser light source 210 and the sample 230 so that the beam diameter becomes smaller than the thickness of the sample 230.

The area of the spot 240 is evaluated by using a brightness profile function of image processing software for a spot image taken with a digital camera. As an example of the brightness profile function of the image processing software, there is an ImageJ 1.48v Plot profile function. In the present application, the full width at half maximum of the peak intensity is defined as the area of the spot 240. When the shape of the spot 240 is substantially rectangular, the area S ₀ can be calculated by the product of the lengths of the vertical and horizontal sides of the spot 240.

The ratio S ₁ / S ₀ of S ₀ and S ₁ obtained in this way can be used as an index representing the straightness of light in the glass plate. That is, it can be said that the smaller the ratio S ₁ / S ₀ (that is, closer to 1), the better the straightness of light propagating in the glass plate along the direction perpendicular to the end face of the glass plate.

The glass plate according to an embodiment of the present invention has a ratio S ₁ / S ₀ of 2.25 or less. The ratio S ₁ / S ₀ is more preferably 2.0 or less, and most preferably 1.5 or less.

(Color of glass plate)
Since the glass plate according to one embodiment of the present invention has high transparency, it can be used in place of an acrylic plate in combination with an acrylic plate or in applications where an acrylic plate is used. Therefore, it is preferable that the color of the glass plate is close to the color of the acrylic plate. Acrylic, unlike glass, has a slight coloration although it is extremely transparent because it does not contain iron impurities in the manufacturing process. In the glass plate by one Embodiment of this invention, the glass close | similar to the color of an acrylic board can be obtained by adjusting the quantity of the iron component mentioned above and various transition metal ions precisely according to a glass composition. Hereinafter, this feature will be described quantitatively.

In one embodiment of the present invention, from the first cut surface of sample A prepared by the above method from a glass plate, from the transmission spectrum T1 at an optical path length of 50 mm measured in the normal direction of the first cut surface. CIE 1976 (L ^* , a ^* , b ^* ) calculated under the C light source The values of L ^* , a ^* , b ^* on the color system and CIE 1976 (L ^* , a ^* , b under the C light source) ^* ) The value of the color difference ΔE ^* _{ab from} the acrylic value with an optical path length of 50 mm in the color system is 1.5 or less. The value of the color difference ΔE ^* _ab is preferably 1.25 or less, more preferably 1.0 or less, even more preferably 0.75 or less, particularly preferably 0.6 or less, and most preferably 0.5 or less.

Here, the values of L ^* , a ^* , and b ^* in acrylic having a light path length of 50 mm under a C light source are L ^* = 96.844, a ^* = − 0.127, and b ^* = 0.491.

  Moreover, since the glass plate by one Embodiment of this invention has high transparency, there exists a possibility that the delicate coloring which could not be recognized with the conventional glass plate affects the designability. For example, by passing through a strongly reducing environment during glass forming in the float process or fusion process, various metal colloids such as Sn, S, Sb, Cu, Fe, and Se may be deposited on the outermost surface of the glass plate to cause coloring. This coloring can occur only in the range of several μm at most on the surface layer. However, in a glass having unprecedented transparency, depending on the angle when viewed from the end face direction, the glass plate may be colored or dull. May give an impression. In order to prevent such deterioration in designability, for example, in the case of the fusion method, the degree of reduction of the atmosphere in the tin bath is controlled in the case of the float method, which controls the degree of reduction of the atmosphere in the region from molding to slow cooling. Coloring may be suppressed by a method such as control of removing metal impurities in the tin bath, or the colored layer may be removed by polishing.

(Glass plate form)
The glass plate 100 preferably has a length of at least one side of 50 mm or more so that the transparency when viewed from the end face direction is conspicuous. It is preferably 200 mm or more, more preferably 300 mm or more, and particularly preferably 500 mm or more. The length of the short sides of main surfaces 120A and 120B is more preferably 200 mm or more, further preferably 300 mm or more, and particularly preferably 500 mm or more.

  In glass plate 100, the surface of first main surface 120A and / or second main surface 120B may be smoothed. For example, in the first or second main surface 120A, 120B, the arithmetic average roughness Ra may be 0.8 μm or less.

  Further, in the glass plate 100, at least one of the end faces 130A to 130D may have a smooth surface. For example, the arithmetic average roughness Ra may be 0.8 μm or less on the smoothed end face. Ra is more preferably 0.5 μm or less, further preferably 0.4 μm or less, and particularly preferably 0.1 μm or less.

  Thereby, the design property of the glass plate 100 improves further. For example, all of the first end surface 130A to the fourth end surface 130D may be smoothed.

  In the glass plate 100, at least one of the connection portions LA-1 to LA-4 between the first main surface 120A and the first end surface 130A may be chamfered (see FIG. 1). Similarly, at least one of the connection portions LB-1 to LB-4 between the second main surface 120B and the first end surface 130A may be chamfered. More preferably, the exposed portions of the connection portions LA-1 to LA-4 and the connection portions LB-1 to LB-4 are all chamfered.

Since the glass plate 100 has a higher refractive index than acrylic, in this case, the chamfered portion has a brilliant and high-quality impression, and the design of the glass plate 100 is further improved. To give a sense of luxury, the refractive index _{n d} of the glass plate at a wavelength of 587.6nm is good is 1.500 or more. n _d is preferably 1.510 or more, more preferably 1.515 or more, and further preferably 1.520 or more.

  Further, in the glass plate 100, the connection part SA-1 between the first end face 130A and the second end face 130B, the connection part SA-2 between the second end face 130B and the third end face 130C, the third end face 130C and the first end face 130C. It is preferable that at least one of the connection portion SA-3 of the fourth end surface 130D and the connection portion SA-4 of the fourth end surface 130D and the first end surface 130A is chamfered. In particular, it is more preferable that the exposed portions of the connection portions SA-1 to SA-4 are all chamfered.

  In this case, the design of the glass plate 100 is further improved.

  In the above description, the glass plate 100 is assumed to have a rectangular shape having two main surfaces 120A and 120B and four end surfaces 130A to 130D. However, the glass plate 100 according to an embodiment of the present invention may have any shape such as a plate, a disk, and a block having a curved main surface in addition to a rectangle. In order to give three-dimensional design properties, a plurality of glass plates and blocks may be joined and used, or not only the glass plates of the present invention but also used in combination with transparent acrylic. good. Further, it may be used in combination with colored glass, colored plastic, metal material or the like. Since there is no coloring like a conventional glass plate, the color seen through the glass of the present invention does not change when viewed from any direction, so that excellent design can be obtained.

  Note that, for example, in the case of a disk-shaped glass plate, it is necessary to note that there is only one end surface, and therefore there is no connection portion between the end surfaces.

  The thickness of the glass plate is preferably 1.0 mm or more in order to make the design from the end face more impressive. Moreover, if thickness is 1.0 mm or more, since rigidity will be ensured, it will become difficult to bend, and when it compares with an acrylic, it is not only excellent in intensity | strength but a high-class feeling can be obtained. On the other hand, the plate thickness required to ensure the same rigidity as acrylic can be made significantly thinner than acrylic, so the effect of sharpening the impression viewed from the end face direction can also be obtained. The thickness may be appropriately selected from 1.8 mm or more, 2.0 mm or more, 2.5 mm or more, 3.5 mm or more, 6.0 mm or more, or 8.0 mm or more depending on the purpose.

  In addition, the purpose of utilizing transparency that is more transparent than design, for example, the use of a light guide for an edge light type planar light emitting element, and the weight reduction such as the decoration use of an electronic device. In applications where space saving is the main purpose, the glass plate may be thinner than 1.0 mm. However, the thickness of the glass of the present invention is preferably greater than 0.3 mm, more preferably greater than 0.5 mm, and particularly preferably greater than 0.7 mm. In use in these applications, the thickness is preferably 3.0 mm or less in order to prevent an increase in weight. It is more preferably 2.6 mm or less, further preferably 2.2 mm or less, and particularly preferably 2.0 mm or less.

  Further, a plurality of plates may be used together with a resin for the purpose of obtaining a thicker plate or preventing scattering when broken. Moreover, you may use a glass plate, after giving air cooling reinforcement | strengthening, chemical strengthening, etc. according to the objective. In addition, various functional films such as an antireflection film and an anti-fingerprint film may be coated and used in order to enhance the design feeling by enhancing the transparency.

(Composition of glass plate)
The composition of the glass plate 100 according to an embodiment of the present invention is not particularly limited as long as it has the above-described characteristics. The following three types (glass having glass composition A, glass composition B, and glass composition C) are given as typical examples, but the glass composition of the glass plate according to the present invention is limited to the glass composition shown here. It is not a thing.

For example, glass plates of the glass composition A is a mass percentage based on oxides, essentially, a SiO ₂ 60-80%, the _Al 2 _{O 3 0~7%,} the MgO 0%, the CaO 0-20% 0-15% of SrO 0 to 15% of BaO, Na ₂ O and 3-20%, and _{K 2} O may also contain 0-10%.

Or the glass plate of glass composition B is a mass percentage display on the basis of oxide, and is substantially 45 to 80% of SiO ₂ , Al ₂ O ₃ is more than 7% and 30% or less, and B ₂ O ₃ is 0 to 0%. 15%, the MgO 0 to 15% Less than six% of CaO, the SrO 0 to 5% 0 to 5% of BaO, 7 to 20% of Na ₂ O, 0% to _{K 2} O, and ZrO ₂ may be contained in an amount of 0 to 10%.

Alternatively, the glass plate of the glass composition C is a mass percentage based on oxides, essentially, a SiO ₂ 45 to 70%, the _{Al 2 O 3 10~30%, B} 2 O 3 and 0 to 15% And containing at least one component selected from the group consisting of MgO, CaO, SrO and BaO in a total of 5 to 30%, and at least one selected from the group consisting of Li ₂ O, Na ₂ O and K ₂ O A total of 0% or less and less than 3% of seed components may be included.

  Hereinafter, the composition range of each component contained in the glass plate will be described.

In the present application, the glass component is expressed in terms of oxides such as SiO ₂ and Al ₂ O ₃ , and the content (glass composition) of each component with respect to the entire glass is the oxide based mass percentage, or mass ppm (mass percentage). Is simply expressed as%, or mass ppm may be simply expressed as ppm).

SiO ₂ is a main component of glass.

In order to maintain the weather resistance and devitrification properties of the glass, the content of SiO ₂ is preferably 60% or more, more preferably 63% or more in the glass composition A in terms of the oxide-based mass percentage. In composition B, it is preferably 45% or more, more preferably 50% or more, and in glass composition C, it is preferably 45% or more, more preferably 50% or more.
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 glass composition A, preferably 80% or less, more preferably 75% or less, in the glass composition B, preferably 80% or less, more preferably 70% or less, and in the glass composition C , Preferably 70% or less, more preferably 65% or less.

Al ₂ O ₃ is an essential component for improving the weather resistance of glass in the glass compositions B and C. In order to maintain practically necessary weather resistance in the glass plate 100, the content of Al ₂ O ₃ is preferably 1% or more, more preferably 2% or more in the glass composition A, and the glass composition B Is preferably more than 7%, more preferably 10% or more. In the glass composition C, it is preferably 10% or more, more preferably 13% or more.

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 in the glass composition A. Is 7% or less, more preferably 5% or less. In the glass composition B, preferably 30% or less, more preferably 23% or less. In the glass composition 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 and weather resistance. However, in a soda lime silicate glass such as the glass composition A, the striae due to volatilization (ream) Is preferably 5% or less, more preferably 2% or less, particularly preferably 1% or less, and substantially does not contain. Is most preferred. In the present application, “substantially does not contain” means that the target substance does not exist unless it is included as an inevitable impurity.

In the glass compositions B and C, the content of B ₂ O ₃ is preferably 15% or less, more preferably 12% or less.

Alkali metal oxides such as Li ₂ O, Na ₂ O, and K ₂ O are useful components for accelerating melting of glass raw materials and adjusting thermal expansion, viscosity, and the like.

Therefore, in the glass composition A, the content of Na ₂ O is preferably 3% or more, more preferably 8% or more. In the glass composition B, the content of Na2O is preferably 7% or more, more preferably 10% or more. However, the content of Na ₂ O is preferably 20% or less in the glass compositions 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 glass composition C is 3% or less, more preferably 1% or less in the glass composition C.

Further, the content of K ₂ O is preferably 10% or less, more preferably 7% or less in the glass compositions A and B, and preferably 2% or less, more preferably 1% in the glass composition C. It is as follows.

Further, Li ₂ O is an optional component, but in order to facilitate vitrification, to keep the iron content contained as an impurity derived from the raw material low, and to keep the batch cost low, in glass compositions A, B and C , Li ₂ O can be contained at 2% or less.

In addition, 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 the glass composition A and B in order to maintain the foam quality of the produced glass. Is preferably 5% to 20%, more preferably 8% to 15%, and in the glass composition C, 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, viscosity, and the like.

  MgO has the effect of lowering the viscosity during glass melting and promoting the melting. Moreover, since there exists an effect | action which reduces specific gravity and makes a glass plate hard to be wrinkled, it can be contained in glass composition 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 in the glass composition A is preferably 10% or less, more preferably 8% or less, and still more preferably. In glass composition B, it is preferably 15% or less, more preferably 12% or less, and even more preferably 10% or less. In glass composition C, it is preferably 10% or less, more preferably 5%. % Or less.

  CaO is a component that promotes melting of the glass raw material and adjusts viscosity, thermal expansion, and the like, and therefore can be contained in the glass compositions A, B, and C. In order to obtain the above action, in the glass composition A, the content of CaO is preferably 3% or more, more preferably 5% or more. In order to improve devitrification, the glass composition A is preferably 20% or less, more preferably 10% or less, and the glass composition B is 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. In order to obtain such an effect, SrO can be contained in the glass compositions A, B and C. However, in order to keep the thermal expansion coefficient of the glass low, in the glass compositions A and C, the SrO content is preferably 15% or less, more preferably 10% or less, and in the glass composition B, 5%. % Or less, and more preferably 3% or less.

  BaO, like SrO, has the effect of increasing the thermal expansion coefficient 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, the content of BaO in the glass compositions A and C is preferably 15% or less, more preferably 10% or less, and 5% in the glass composition B. The content is preferably set to 3% or less, more preferably 3% or less.

  Further, the total content of these alkaline earth metal oxides (MgO + CaO + SrO + BaO) is preferably 10 in the glass composition A in order to keep the coefficient of thermal expansion low, good devitrification properties, and maintain strength. % Or more, more preferably 13% or more. In the glass composition B, 1% or more, more preferably 10% or more. In the glass composition C, preferably 5% or more, more preferably 10% or more. . However, if the amount is increased, the amount of other components is relatively reduced, which causes a problem in devitrification characteristics and strength. Therefore, in the glass composition A, 30% or less is preferable, and more preferably 27% or less. In composition B, it is preferably 15% or less, more preferably 10% or less, and in glass composition C, it is preferably 30% or less, more preferably 20% or less.

In the glass compositions A, B and C, ZrO ₂ may be contained as an optional component in an amount of 10% or less, preferably 5% or less, in order to improve the heat resistance and surface hardness of the glass. However, if it exceeds 10%, the glass tends to be devitrified, which is not preferable.

Further, the glass plate 100 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.

Moreover, the glass plate 100 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.

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 depending on the purpose of adjusting the amount of Fe ^{2+ in} the glass. However, As ₂ O ₃ is not positively contained from the environmental viewpoint.

Glass plate 100 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. From the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm, the content of TiO ₂ is more preferably 500 ppm or less, and particularly preferably 100 ppm or less.

Glass plate 100 may include CeO _2. CeO ₂ has the effect of reducing the redox of iron, and can reduce the absorption of glass at a wavelength of 400 to 700 nm. However, if containing CeO ₂ in a large amount, CeO _2, compared the total amount of the glass composition described above to function as a component which absorbs visible light not only causes solarization, and 1000ppm or less Is preferred. 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. When added, it is preferable that 0.1 ppm or more is always added in order to easily suppress variations in product characteristics during production, particularly color variations. Addition of 1.0 ppm or more is preferable for color control, and addition of 5.0 ppm or more is more preferable. When the effect of reducing the redox of iron is expected, it is preferable to add at least the same amount as the amount of iron (mass ppm) converted to Fe ₂ O ₃ contained in the glass, and to add at least 1.5 times the amount of iron It is more preferable to add 3 times or more, and it is more preferable to add 5 times or more.

It is preferable that the glass plate 100 is controlling the amount of β-OH contained in the glass according to the amount of Fe ²⁺ contained in the glass. This is because, in a glass in which iron components, particularly Fe ²⁺ are excessively excluded, when it is difficult to improve the homogeneity at the time of melting as described above, the β-OH amount is controlled according to the Fe ²⁺ amount. This is because the present inventors have clarified that this is effective in improving the homogeneity at the time of dissolution. The β-OH amount in the glass plate according to an embodiment of the present invention is preferably 0.015 × [Fe ²⁺ ] or more, more preferably 0.025 × [Fe ²⁺ ] or more, and Most preferably, it is 03 × [Fe ²⁺ ] or more. Here, [Fe ²⁺ ] is the amount of Fe ²⁺ (mass ppm) converted to Fe ₂ O ₃ .

  Moreover, the glass plate 100 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, more preferably 0.8 ppm or less, and 0.6 ppm or less from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm. Is more preferable, and 0.5 ppm or less is particularly preferable.

The glass plate 100 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 preferably not more than 2.0 ppm, more preferably not more than 1.6 ppm, and more preferably 1.2 ppm from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm. More preferably, it is more preferably 1.0 ppm or less, even more preferably 0.8 ppm or less, and most preferably 0.6 ppm or less.

The glass plate 100 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 preferably 30 ppm or less, more preferably 20 ppm or less, even more preferably 15 ppm or less, from the viewpoint of not reducing the internal transmittance of the glass plate at a wavelength of 400 to 700 nm. It is particularly preferable that the content be 10 ppm or less.

The glass plate 100 may include at least one component selected from the group consisting of Se, CoO, V ₂ O ₅ and CuO. When these components are contained, they also function as components that absorb visible light. Therefore, the content of each component is preferably 5.0 ppm or less, more preferably 2.0 ppm or less. More preferably, it is 0 ppm or less. In particular, it is most preferable that these components are not substantially contained so as not to reduce the internal transmittance of the glass plate at a wavelength of 400 to 700 nm.

  The glass plate 100 has a low content of contaminants, a high transmittance, and excellent transparency when viewed from the normal direction of the end face. Can be applied. For example, the glass plate 100 is applied to a window of a building and a vehicle, an interior of a building, furniture, a display case, a transparent member of an electronic device, a substrate glass for a solar cell, a cover glass, and a light guide plate of a surface lighting device. Can do.

(About the manufacturing method of the glass plate by one Embodiment of this invention)
Next, an example of a glass plate manufacturing method (hereinafter referred to as “first manufacturing method”) according to an embodiment of the present invention having the above-described features will be briefly described.

  FIG. 3 shows a schematic flow of the first manufacturing method.

As shown in FIG. 3, the first manufacturing method is:
(1) a step (step S110) of manufacturing a molten glass by melting a glass raw material;
(2) a step of forming molten glass on a glass ribbon (step S120);
(3) a step of cooling the glass ribbon (step S130).

  Hereinafter, each process will be described.

(Process S110)
First, a glass raw material is prepared by mixing predetermined raw material components. Moreover, this glass raw material is heated and a molten glass is manufactured.

The molten glass is prepared so as not to contain iron components (particularly Fe ²⁺ ) as impurities as much as possible. For this reason, a high-purity glass raw material is used. Further, the mixing process and the dissolving process are performed in an environment with a high cleanliness.

  However, the glass raw material from which iron is excessively excluded has a characteristic that it is difficult to absorb infrared light during melting. For this reason, in order to obtain molten glass from such a glass raw material with few iron components, it is necessary to administer a lot of energy to a glass raw material, and to heat a glass raw material. As a result, the energy efficiency in the manufacturing process is reduced to an unrealistic level.

  In such a heated state, the composition changes between the top and bottom of the molten glass, and the composition of the finally obtained glass plate may be inhomogeneous. Furthermore, the operation in such a high temperature state tends to cause breakage and deterioration of the manufacturing equipment.

  In the first manufacturing method, in order to cope with such a problem, the content of transition metal ions selected from the group consisting of Ni, Mn, Cr, Co, V, and Se contained in the glass raw material is controlled. That is, these transition metal ions are adjusted so that the total content of the glass raw material is 0.1 ppm by mass or more.

  These transition metal ions have the property of absorbing light in the wavelength range from the ultraviolet region to the near infrared region. For this reason, when a molten glass contains these transition metal ions, even if an iron component is excessively excluded, heating becomes relatively easy, and the above-described problems are reduced.

  However, these transition metal ions also function as a coloring component of glass. For this reason, when many of these transition metal ions are contained in the glass raw material, the transparency of the finally obtained glass plate is lowered.

  Therefore, in the first manufacturing method, the total sum of transition metal ions selected from the group consisting of Ni, Mn, Cr, Co, V, and Se is controlled to be 30 mass ppm or less. Thereby, in the first manufacturing method, it is possible to manufacture a homogeneous glass plate by a realistic process without adversely affecting the transparency.

Also, optimization of the glass cullet ratio contained in the glass raw material, control of the stirring speed by a stirrer in the glass melting tank, temperature control in the depth direction by burner heating in the upper space of the molten glass and electric heating to the molten glass Combine some or all of the temperature gradient control from the maximum temperature range to the clarification temperature range in the dissolution tank, or in addition to these methods, the amount of β-OH contained in the glass By controlling according to the amount of Fe ²⁺ contained in the glass, it is possible to maintain the homogeneity in the depth direction in the kiln even in a glass in which iron components, particularly Fe ²⁺ are excessively excluded.

(Process S120)
Next, the molten glass obtained in the above process is formed into a glass ribbon. As the forming method, a float method, a roll-out method, a fusion method, a mold cast method, or the like is used. For example, in the float process, the molten glass flows into a float bath in which molten tin has been previously stored, floats on the molten tin, forms a glass ribbon, and forms a uniform thickness while moving over the molten tin. Is done.

  In the float process, it is preferable to suppress coloring in both the surface layer on the atmosphere side and the molten tin side of the glass plate by controlling the environment in the float bath. For example, for the purpose of controlling the degree of reduction of the atmosphere, the concentration distribution of reducing gas such as hydrogen or nitrogen may be adjusted. In addition, metal impurities present in the molten tin, particularly a large amount of iron, can be a coloring factor on the molten tin surface of the glass, and therefore it is preferable to remove this. For example, by cooling molten tin with a water pipe, metal impurities or an alloy of tin and metal impurities may be preferentially precipitated around the water pipe and removed from the molten tin. Alternatively, the metal impurities or an alloy of tin and metal impurities may be preferentially precipitated by inserting an electrode into the molten tin and reduced, and then removed from the molten tin. Alternatively, before producing the desired glass, another glass adjusted so that the added amount of various metal impurities is equal to or lower than the amount of metal impurities in the molten tin is allowed to flow into the float bath, and the low impurity The impurities may be removed from the molten tin by allowing the glass to absorb the impurities in the molten tin. Alternatively, an induction magnetic field may be locally generated, and tin containing a large amount of metal impurities may be collected and removed around the magnetic field. Further, a part or all of the molten tin may be replaced with tin having a low content of metal impurities. By combining any one or more of these methods, the molten tin can be kept clean. Furthermore, coloring may be suppressed by shortening the contact time with molten tin. By these devices, it is possible to effectively suppress coloring on the molten tin surface of the glass.

  As for the molding method, a general molding method including the above-mentioned methods is appropriately selected in consideration of the temperature range suitable for molding depending on the glass composition, the thickness of the target plate, the convenience of the manufacturing equipment, etc. Good.

(Step S130)
Thereafter, the glass ribbon is gradually cooled to a predetermined temperature. Moreover, a glass plate is obtained by cutting the glass ribbon. The main surface of the glass plate may be as it is formed or may be polished and finished.

  The glass plate by one Embodiment of this invention can be manufactured according to the above process.

  Heretofore, an example of the glass manufacturing method according to an embodiment of the present invention has been described in detail. However, the manufacturing method of the glass plate by one Embodiment of this invention is not limited to the above description.

  Examples of the present invention will be described below. In the following description, Examples 1 to 12 are examples, and Examples 13 to 16 are comparative examples.

(Example 1)
A glass plate was manufactured by the method shown in FIG. The float method was adopted as a forming method. The mother composition of the glass is in the range of the glass composition A described above. Since the amounts of iron components and various transition metal ions contained in the raw material are extremely small, the input amount was appropriately adjusted so that it could be blended homogeneously in the raw material mixing process. In particular, since the transition metal ion raw material is expensive, the raw material configuration was also optimized so as to use those contained as impurities in other raw materials in order to reduce costs. In the melting step, the temperature gradient of the glass melt in the kiln was controlled by using a stirrer whose rotation speed was controlled so that the glass melt became homogeneous, and also using auxiliary heating other than the burner used for normal combustion. In addition, the humidity of the raw material and the glass cullet ratio in the raw material batch were controlled so that β-OH was within an appropriate range. By these ideas, the glass raw material could be melted uniformly. Thereafter, a glass plate (referred to as “glass plate 1”) having a thickness of 2.5 mm was produced through a glass ribbon production process and a cooling process.

(Examples 2 to 4)
A glass plate was produced in the same manner as in Example 1. The mother composition of the glass is in the range of the glass composition A described above. In Examples 2 to 4, the composition of the raw glass and the amount of β-OH in the glass were changed from those in Example 1, but the other production conditions were the same as in Example 1. By these ideas, the glass raw material could be melted uniformly. Thereafter, through a glass ribbon manufacturing process and a cooling process, in Example 2, a glass plate having a thickness of 2.1 mm (glass plate 2), in Example 3, a glass plate having a thickness of 1.8 mm (glass plate 3), Example 4 was used. Then, a glass plate (glass plate 4) having a thickness of 5.0 mm was produced.

(Example 5 to Example 7)
A glass plate was produced using a roll-out method as a method for forming the glass plate. The glass mother composition is in the range of the glass composition A described above, but was changed from that in Example 1 in consideration of the difference in heating state due to different kiln structure and molding method, and the difference in viscosity near the molding temperature. . By these ideas, the glass raw material could be melted uniformly. Thereafter, through a glass ribbon manufacturing process, a cooling process, and a polishing process, a glass plate having a thickness of 2.5 mm (glass plate 5) in Example 5, and a glass plate having a thickness of 4.0 mm in Examples 6 and 7 ( A glass plate 6 and a glass plate 7) were produced.

(Examples 8 to 12)
The glass plate was manufactured using the mold cast method as a shaping | molding method of a glass plate. The mother compositions of Examples 8 to 10 are in the above glass composition A range, the mother composition in Example 11 is in the above glass composition B range, and the mother composition in Example 12 is in the above glass composition C range. is there. Since the amount of the iron component and various transition metal ions contained in the raw material is extremely small, a material previously mixed homogeneously with a part of the raw material silica sand was used so that it could be blended homogeneously in the raw material mixing process. Furthermore, a homogeneous glass melt was obtained by using a stirrer with a controlled rotation speed and by controlling the melting time, melting temperature profile and atmosphere. This is cast into a preheated 200 mm × 600 mm mold and subjected to processing steps such as a slow cooling step, cutting and polishing, and in Examples 8 to 10, a glass plate having a thickness of 5.0 mm (glass plates 8 to 10), In No. 11, a glass plate (glass plate 11) having a thickness of 1.0 mm was produced. In Example 12, a glass plate having a thickness of 1.8 mm (glass plate 12) was produced.

(Example 13)
A glass plate was manufactured by the method shown in FIG. The float method was adopted as a forming method. The glass mother composition is in the range of the glass composition A described above and is the same as the glass plate 1. However, in Example 13, Ni, Mn, Cr, Co, and V were not added, and the β-OH was set to be low, and a glass plate (glass plate 13) having a thickness of 2.5 mm was obtained.

(Example 14)
A glass plate was manufactured by the method shown in FIG. The float method was adopted as a forming method. The mother composition of the glass is in the range of the glass composition A described above, and is a high transmission soda lime silicate glass used for the substrate glass for solar cells. At the time of melting the glass, the glass plate was produced under production conditions such that homogeneity when viewed from the normal direction of the main surface of the glass plate was sufficiently obtained, and a glass plate (glass plate 14) having a thickness of 1.8 mm was obtained.

(Example 15)
A glass plate was produced using the same mold casting method as in Example 8 as the method for forming the glass plate. The mother composition of the glass is in the range of the glass composition A described above, and Ni, Mn, and Cr are added as coloring components to the highly transparent soda lime silicate glass used as the cover glass for solar cells. At the time of glass melting, a glass plate (glass plate 15) having a thickness of 5.0 mm is polished by polishing a product manufactured under such manufacturing conditions that sufficient homogeneity is obtained when viewed from the normal direction of the main surface of the glass plate. Obtained.

(Example 16)
Example 16 is a commercially available general transparent acrylic plate (acrylic plate 1).

Table 1 below collectively shows the composition of glass plates 1 to 15 and the forming method, the stirrer use state during melting, and the presence or absence of auxiliary heating. Total iron oxide (t-Fe ₂ O ₃ ) amount (mass ppm), Sb ₂ O ₃ amount (mass ppm), SO ₃ amount (mass ppm), TiO ₂ amount (mass ppm) were determined by fluorescent X-ray analysis. ^{The 2+} content was measured according to ASTM C169-92. The measured Fe ²⁺ content was expressed in terms of Fe ₂ O ₃ .

When the Fe ²⁺ content in the glass was less than 4.0 ppm by mass, the Fe ²⁺ amount was determined by the following method. First, the total iron content appropriately adjusted ^{Fe 2+} content in a manner analogous to ASTMC169-92 the glass was prepared to greater than 4.0 mass ppm ^{Fe 2+} content in _{C Fe @ 2 +} (ppm by weight on the same glass matrix composition ) Was measured. The spectral transmittance of this glass in the wavelength range of 1000 to 1250 nm was measured. Since the minimum value% T _MIN of the transmittance in this range is proportional to the Fe ²⁺ content in the glass, the calibration curve Y = (C _{Fe 2+} /% T _MIN ) × X is used to contain Fe ^{2+ in} the glass. The amount was calculated. Here, X is a minimum value of spectral transmittance in a wavelength range of 1000 to 1250 nm of glass having an Fe ²⁺ content of less than 4.0 mass ppm, and Y is an Fe ²⁺ content contained in the glass.

Further, the total cerium oxide amount, Ni amount, Cr amount, Mn amount, Co amount, V amount, and Se amount converted to CeO ₂ contained in the glass were determined by ICP emission analysis.

Β-OH (mm ⁻¹ ), which is an index of the moisture concentration contained in the glass, was calculated from the infrared transmission spectrum of the glass measured by FT-IR by the following equation.

β-OH (mm ⁻¹ ) = Log ₁₀ (T _{3500 cm} ⁻¹ / T _{4000 cm} ⁻¹ ) / θ
Here, T ₃₅₀₀ cm ⁻¹ and T ₄₀₀₀ cm ⁻¹ are transmittances (%) at wave numbers 3500 cm ⁻¹ and wave numbers 4000 cm ⁻¹ , respectively, and θ is the thickness (mm) of the glass plate.

（評価）
前述のガラス板１〜ガラス板１５およびアクリル板１を用いて、以下の評価を行った。

(Evaluation)
The following evaluation was performed using the glass plate 1 to glass plate 15 and the acrylic plate 1 described above.

  Samples for evaluation were produced on each glass plate and acrylic plate by the following method.

  First, in each of the glass plates 1 to 15 and the acrylic plate 1, by cutting in a direction perpendicular to the first main surface in accordance with the respective plate thickness θ (mm), the vertical direction 10θ X Samples having a width of 50 mm were taken out (referred to as “sample 1” to “sample 15” and “acrylic sample”, respectively).

  Of the four cut surfaces of the sample, the two opposite surfaces having a length of 5 mm are referred to as first and third cut surfaces, respectively, and the two opposite surfaces having a length of 50 mm are respectively referred to as the second and fourth cut surfaces. Called.

  Next, the four cut surfaces of each sample were polished until the arithmetic average roughness Ra was 0.1 μm or less. The cut surface was finally mirror-finished with abrasive grains corresponding to # 4000 to # 8000. In addition, about the glass plates 1-4, 13, and 14 and the acrylic sample which were produced by the float process, since the main surface of each sample was comparatively smooth from the stage immediately after collection | recovery (arithmetic mean roughness Ra <= 0.1micrometer) The polishing treatment was not performed.

Next, in each sample, using a spectrophotometer (U-4150: manufactured by Hitachi High-Tech Co., Ltd.), the optical path length is 50 mm in the wavelength range of 400 nm to 700 nm in the normal direction of the first cut surface of each sample. The transmission spectrum T1 was measured. Further, a transmission spectrum T2 at an optical path length of 5 mm in a wavelength range of 400 nm to 700 nm was measured in the normal direction of the second cut surface. T1 was measured using a long sample measurement unit. At that time, for the purpose of adjusting the beam width of the light incident on the sample, a slit having a width of 0.3 mm was installed on the sample incident surface side for measurement. L ^* , a ^* , b ^* values in the CIE 1976 (L ^* a ^* b ^* ) color system were calculated according to the method described in JIS Z 8781-4 (2013) for the measured transmission spectra T1 and T2. . As the tristimulus values X _n , Y _n , and Z _n of the white stimulus, the values of C light source, X _n = 0.980721264484213, Y _n = 1, Z _n = 1.182225809830395, were used.

From the L ^* , a ^* , and b ^* values at T1, and the L ^* , a ^* , and b ^* values at T2, the color difference ΔE ^* _ab (denoted as ΔE1) between T1 and T2 was obtained. Further, ^L in T1 ^*, a *, ^{b *} values and, ^L in acrylic sample ^*, a *, the ^{b *} value, obtains the color difference Delta] E ^* _ab of the optical path length 50mm of each sample acrylic (.DELTA.E2 hereinafter) It was.

Table 2 below shows L ^* and (a ^{* 2} + b ^* ) in ΔE1, ΔE2, and T1 obtained in Sample 1 (glass plate 1) to Sample 15 (glass plate 15) and acrylic plate (acrylic sample), respectively ^{. 2} ) The value of ^0.5 is shown collectively.

(Evaluation of straight line characteristics of light)
The straight light characteristics of each glass plate and acrylic plate were evaluated by the method described above.

  The sample for evaluation described above was used as the sample.

  First, a white screen (printed with grids with 1 mm intervals to facilitate size measurement) was installed vertically at a position 160 mm from the laser light source. A semiconductor laser light source having a wavelength of 635 nm was used as the laser light source.

In this state, laser light was irradiated from the laser light source toward the white screen. The area S ₀ of the spot (referred to as “reference spot”) formed on the white screen was calculated.

Next, either Sample 1 to Sample 15 or an acrylic sample was placed between the laser light source and the white screen, and the same measurement was performed. The sample was arranged so that the laser beam was applied to the substantially central portion of the first or third cut surface (irradiation surface) of the sample. The distance from the laser light source to the irradiation surface of the sample is 40 mm. The area S ₁ of the spot (referred to as “evaluation spot”) formed on the white screen was measured.

From these measurements, the ratio S ₁ / S ₀ was determined for each of Samples 1 to 15 and the acrylic sample.

Table 2 described above collectively shows the ratios S ₁ / S ₀ obtained in Sample 1 (glass plate 1) to Sample 15 (glass plate 15) and the acrylic sample.

測定の結果、ガラス板１〜１２では光路長５０ｍｍでの明度Ｌ^＊が９５．９以上であり、アクリルに近い高い透明性を有していた。また、彩度（ａ^＊２＋ｂ^＊２）^０．５の値が１．８以下とアクリルの３倍以下に抑えられており、光路長が長くても比較的透明な印象を実現していた。さらに、主表面方向と端面方向での色差ΔＥ１は１．５を大きく下回っていた。なお、ＮＢＳ単位（米国標準局）では色差の感覚について、０．５以下ではかすかに感じられる程度であり、１．５以下であればわずかに感じられる程度としているが、明度が高いと色差はより感じにくくなることが知られており、実際本実施例のサンプル１〜１２においては主表面方向と端面方向での色差はまったく感じられなかった。また、ガラス板１〜１２において、同じ光路長５０ｍｍにおけるアクリルとの色差も１．５を大きく下回っており、色味についてアクリルとの違いをほとんど感じることはなかった。

As a result of the measurement, the glass plates 1 to 12 had a lightness L ^* of 95.9 or more at an optical path length of 50 mm, and had high transparency close to acrylic. In addition, the value of saturation (a ^{* 2} + b ^{* 2} ) ^0.5 was suppressed to 1.8 or less, which is 3 times or less than acrylic, and a relatively transparent impression was realized even if the optical path length was long. . Furthermore, the color difference ΔE1 between the main surface direction and the end surface direction was much less than 1.5. In the NBS unit (US National Bureau of Standards), the color difference sensation is slightly felt when it is 0.5 or less and slightly felt when it is 1.5 or less. It is known that it becomes harder to feel. In fact, in samples 1 to 12 of this example, no color difference between the main surface direction and the end surface direction was felt. Moreover, in the glass plates 1-12, the color difference with the acryl in the same optical path length of 50 mm is also much less than 1.5, and the difference with an acryl was hardly felt about the color.

On the other hand, in the glass plates 14 and 15, the lightness L ^* at an optical path length of 50 mm was less than 95.9, and it was found that the transparency was clearly inferior to acrylic. In addition, the saturation exceeded 1.8, and when the optical path length became longer, the coloring was strongly felt. Furthermore, since the color difference ΔE1 between the main surface direction and the end surface direction exceeds 1.5, the color difference between the main surface direction and the end surface direction is felt strongly, and it has been found that the design is poor.

In the glass plates 1 to 12, the value of S ₁ / S ₀ was significantly lower than 2.25, and almost no image distortion was felt when viewed from the end surface direction of the plate.
The glass plate 13 was the same as the glass plate 3 in terms of transparency, but the value of S ₁ / S ₀ exceeded 2.25, and the image distortion was clearly seen when viewed from the end face direction of the plate. I felt it. Even in the glass plates 14 and 15, since the value of S ₁ / S ₀ exceeded 2.25, image distortion was felt. Here, although the glass plate 13 had a smaller value of S ₁ / S ₀ than the glass plates 14 and 15, the distortion of the image was clearly felt than the glass plates 14 and 15 because of its high transparency.

  Thus, in the glass plate 1 to the glass plate 12, even when viewed from either the main surface side or the end surface side, a glass plate excellent in design is provided that is colorless and transparent and substantially free of image distortion. It was confirmed that it was possible.

DESCRIPTION OF SYMBOLS 100 Glass plate 120A 1st main surface 120B 2nd main surface 130-130D End surface 200 Apparatus 210 Laser light source 220 Screen 230 Sample 240 Spot LA-1 to LA-4 Connection part LB-1 to LB-4 Connection part SA- 1 to SA-4 connection part

Claims (13)

A glass plate made of multi-component oxide glass having first and second main surfaces and at least one end surface including the first end surfaces connecting the main surfaces,
The total amount of iron converted to Fe ₂ O ₃ is 1 mass ppm or more and 80 mass ppm or less, Fe ²⁺ converted to Fe ₂ O ₃ is 0.1 mass ppm or more and 10 mass ppm or less,
Metal ions selected from the group consisting of Ni, Mn, Cr, Co, V and Se total 0.1 to 30 ppm by mass,
By cutting the glass plate in a direction perpendicular to the first main surface, a rectangular sample having two side lengths of 5 mm and 50 mm is collected from the central portion of the glass plate, and the sample When one of the two cut surfaces having a length of 5 mm is referred to as a first cut surface and one of the two cut surfaces having a length of 50 mm is referred to as a second cut surface. ,
In the sample A in a state where the four cut surfaces are polished so that the arithmetic average roughness Ra is 0.1 μm or less,
A transmission spectrum T1 having an optical path length of 50 mm measured in the normal direction of the first cut surface at the first cut surface and a normal spectrum direction of the second cut surface at the second cut surface. The value of the color difference ΔE ^* _ab on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated by the transmission spectrum T2 having a path length of 5 mm is 1.5 or less, The value of L ^* on the CIE 1976 (L ^* , a ^* , b ^* ) color system under the C light source calculated from the transmission spectrum T1 is 95.9 or more, and (a ^{* 2} + b ^{* 2} ) ⁰ A glass plate having a value of ^.5 of 1.8 or less. When a screen at a distance of 160 mm from the laser light source is irradiated with laser light having a beam diameter smaller than the thickness of the sample A from the laser light source, the spot area of the laser light formed on the screen is expressed as S _0. age,
When the sample A is disposed between the laser light source and the screen at a distance of 40 mm from the laser light source so that the first cut surface faces the laser light source, the sample A is formed on the screen. when the spot area of the laser beam was set to S _1,
The glass plate according to claim 1, wherein the ratio S ₁ / S ₀ is 2.25 or less. The value of L ^* , a ^* , b ^* on the color system calculated from the transmission spectrum T1, and the optical path length of 50 mm in the CIE 1976 (L ^* , a ^* , b ^* ) color system under a C light source The glass plate of Claim 1 or 2 whose value of color difference (DELTA ⁾ E ^* _ab calculated | required from the value of acrylic L ^* , a ^* , b ^* is 1.5 or less.   The glass plate according to any one of claims 1 to 3, wherein the thickness is 1.0 mm or more.   The glass plate as described in any one of Claims 1-4 whose metal ion selected from the group which consists of Ni, Cr, Co, V, and Se is 5.0 mass ppm or less in total.   The glass plate as described in any one of Claims 1-5 whose Ti and Ce converted into an oxide are 0.1 mass ppm or more and 2000 mass ppm or less in total. Including CeO ₂ 1.0 mass ppm or 500 mass ppm or less, a glass plate according to any one of claims 1 to 6.   The said 1st end surface is a glass plate as described in any one of Claims 1-7 which has arithmetic mean roughness Ra of 0.8 micrometer or less.   The said glass plate WHEREIN: All the end surfaces have the arithmetic mean roughness Ra of 0.8 micrometer or less, The glass plate of Claim 8.   The glass plate according to claim 8 or 9, wherein a connection portion between the first main surface and the first end face is chamfered.   The said glass plate is a glass plate as described in any one of Claims 8-10 in which all the connection parts of the said main surface and the said end surface are chamfered.   The connection part of each end surface is a glass plate as described in any one of Claims 8-11 by which the chamfering is carried out.   The said glass plate WHEREIN: All the surfaces including a chamfering surface have the arithmetic mean roughness Ra of 0.8 micrometer or less, The glass plate of Claims 8-12.

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