WO2014084268A1

WO2014084268A1 - White glass

Info

Publication number: WO2014084268A1
Application number: PCT/JP2013/081935
Authority: WO
Inventors: 盛輝大原; 順子宮坂
Original assignee: 旭硝子株式会社
Priority date: 2012-11-29
Filing date: 2013-11-27
Publication date: 2014-06-05
Also published as: JPWO2014084268A1; TW201422555A

Abstract

The present invention addresses the problem of providing a glass with which the colour of a glass rear surface can be adjusted with high precision, and the impact of colour unevenness on the glass rear surface can be inhibited. The present invention relates to a glass which has an average linear transmittance of not more than 15% at wavelengths in the range 400-800 nm, and which has an average total light transmittance of at least 4% at wavelengths in the range 400-800 nm.

Description

White glass

The present invention relates to a white glass suitably used for a housing of an electronic device, for example, a communication device or an information device that can be carried and used, or a building material for a building or a building (civil engineering structure).

The case of an electronic device such as a mobile phone is used by appropriately selecting a material such as resin or metal in consideration of various factors such as decoration, scratch resistance, workability, and cost. The housing is required not only to store electronic components but also to have design characteristics such as color and decoration.
Color is an important element as one of the design properties.

In recent years, attempts have been made to use glass, which has not been used in the past, as a casing material (Patent Document 1). According to Patent Document 1, in an electronic device such as a mobile phone, it is said that a unique decoration effect with a sense of transparency can be exhibited by forming the casing body from glass.

Electronic devices are equipped with a display device such as a liquid crystal panel on the outer surface of the device. These display devices tend to have high definition and high brightness, and accordingly, backlights serving as light sources also tend to have high brightness. In addition to irradiating the light from the light source on the display device side, the light may reach the back surface of the housing that is multiple-reflected inside the device and is covered.

Further, even in an organic EL (Electro-Luminescence) display that does not require a light source, there is a concern that light leaks from the light emitting element. When metal is used as the material of the housing, there is no problem, but when glass having transparency as described above is used, light from the light source may pass through the housing and be recognized from the outside of the device. For this reason, when glass is used for a housing, a light shielding means such as a coating film for providing the glass with a shielding property against visible light (hereinafter referred to as shielding property) is formed on the back surface of the glass.

As described above, with the increase in the brightness of the light source of the display device, in order to form a coating film having sufficient shielding properties on the back surface (device side) of the glass, the coating film can be formed into a thick film or from a plurality of layers. A film to be formed, which increases the number of processes and increases the cost.

In addition, when the coating film is not formed uniformly, the light is transmitted only in the portion where the coating film is thin, and there is a risk of deteriorating the aesthetics of the device such as locally recognizing the color of the housing brightly. For example, in a concave housing, it is necessary to form a uniform film over the entire concave surface. However, the process of uniformly forming a coating film having sufficient shielding properties on the concave surface is complicated, which increases the cost.

In particular, when obtaining a casing having a white appearance, there is a method of forming a white coating layer on at least one surface of the transparent glass as described above. However, the white paint has high translucency, and sufficient shielding properties cannot be obtained even if the white coating layer is thickened.

Therefore, a black coating layer having a high shielding property is laminated on the white coating layer. In this case, it is necessary to make the white coating layer thick enough to prevent the black coating layer from being recognized. Thus, in order to obtain the housing | casing provided with the high shielding property which exhibits white using a white coating material, there exists a problem that cost becomes very high.

Also, an electronic device that can be used for a mobile phone or the like is required to have high strength for the casing in consideration of damage caused by a drop impact during use or contact damage due to long-term use. For this reason, conventionally, in order to improve the scratch resistance of the glass substrate, the glass is chemically strengthened to form a compressive stress layer on the surface to enhance the scratch resistance of the glass substrate.

Tunnels or tunnels have high temperature and humidity, and the air is contaminated, so the walls deteriorate quickly. In addition, because the daylight is not exposed to the tunnels or tunnels, lighting is necessary not only at night but also in the daytime. However, the power consumed by the tunnels and tunnels throughout the country is enormous, and energy saving is urgently required. ing.

Conventionally, tiles with high reflectivity have been used as interior materials for tunnels or tunnels. By using tiles with high reflectivity, the number of lighting fixtures can be reduced and energy has been saved. In addition, visibility can be improved. In the tunnel interior tiles used so far, a glaze has been applied on the ceramic substrate for the purpose of improving the cleanability, reflectivity or strength.

For example, Patent Document 2 describes a light reflecting tile for tunnel interior in which a glaze is applied for the purpose of increasing the strength on the surface side having a plurality of granular irregularities formed on the surface of a tile base material. Moreover, the glaze which added the zirconia to the transparent glaze and made it cloudy as white glaze is described.

Also, Patent Document 3 describes a highly reflective white tile used as a building material or wall material of a building, and describes that antifouling treatment is performed with a glaze as necessary.

Japanese Unexamined Patent Publication No. 2009-61730 Japanese Unexamined Patent Publication No. 2010-255188 Japanese Unexamined Patent Publication No. 2011-226156

When using glass so as to constitute at least a part of the casing body as shown in FIGS. 5 (a) to 5 (c), the present inventors have found uneven color on the back of the glass if the light shielding property of the glass is low. It was found that color unevenness is easily visible through glass. On the other hand, excellent design properties are required, and it may be necessary to adjust the color of the back of the glass with high accuracy. However, if the light shielding property of the glass is too high, the color of the back of the glass can be adjusted with high accuracy. We found it difficult to adjust.

Therefore, an object of the present invention is to provide a glass capable of suppressing the influence of color unevenness on the back surface of the glass and adjusting the color of the back surface of the glass with high accuracy.

In addition, if a tunnel or tunnel is decorated with tiles, even if glaze is applied to the surface, the cleaning performance, reflection performance, or strength may be reduced due to scratches or chipping on the tile surface caused by handling during construction. It was. In addition, there is a concern that the glaze easily peels due to the difference in thermal expansion between the glaze and the ceramic substrate.

Therefore, the present invention provides a glass that can be used for building materials for tunnels or tunnel interiors and the like that can maintain cleaning performance, reflection performance, and strength even if surface scratches or chipping occurs. Objective.

The inventors of the present invention can cover the color unevenness on the back surface of the glass by setting the average value of the linear transmittance at a wavelength of 400 to 800 nm within a specific range, and also the average value of the total light transmittance at a wavelength of 400 to 800 nm. It was found that the color tone of the back surface of the glass can be adjusted with high accuracy by setting the value to a specific range, and the present invention was completed.

That is, the present invention is as follows.
1. A glass having an average value of linear transmittance at a wavelength of 400 nm to 800 nm of 15% or less and an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more.
2. 2. The glass according to item 1, wherein the maximum value of linear transmittance at a wavelength of 400 nm to 800 nm is 35% or less, and the minimum value of total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more.
3. 3. The glass according to item 1 or 2, which is a phase separation glass.
4). 3. The glass according to item 1 or 2, which is a crystallized glass containing crystals.
5. 5. The glass according to any one of items 1 to 4, wherein the glass has a thickness of 0.2 to 5 mm.
6). A casing glass constituting at least a part of a casing, wherein an average value of linear transmittance at a wavelength of 400 nm to 800 nm is 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more The housing glass.
7). 7. The housing glass according to item 6 above, wherein the housing glass has a functional layer on a surface facing the outer surface of the housing.
8). 8. The housing glass according to item 7, wherein the layer printed on the housing glass constitutes at least a part of the functional layer.
9. A casing made of at least a part of glass, wherein the glass has an average value of linear transmittance at a wavelength of 400 nm to 800 nm of 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more The housing that is.
10. 10. The housing according to 9 above, wherein at least a part of the outer surface portion is the glass, and a functional layer is provided on a surface of the glass facing the housing outer surface.
11. 11. The housing according to item 10 above, wherein the functional layer includes a layer printed on the glass.
12 12. An information terminal comprising the housing according to any one of 9 to 11 above.
13. A glass for building materials having a thickness of 0.5 mm or more, an average value of linear transmittance at a wavelength of 400 nm to 800 nm of 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more.

14 14. The glass for building material as described in 13 above, containing 0 to 25% of Al ₂ O ₃ in terms of mole percentage based on oxide.
15. 15. The building material glass as described in 13 or 14 above, which contains 0.5 to 10% of ZrO ₂ + P ₂ O ₅ + La ₂ O ₃ in terms of mole percentage based on oxide.
16. 16. The building glass according to any one of 13 to 15 above, containing 0 to 15% of Na ₂ O in terms of mass percentage based on oxide.
17. 17. The building material glass according to any one of items 13 to 16, wherein the density is 3.0 g / cm ³ or less.
18. 18. The building material glass according to any one of items 13 to 17, which does not contain filler mixed glass.
19. 19. The glass for building materials as described in any one of 13 to 18 above, which is used for interiors of tunnels or tunnels.
20. 20. The building material glass according to any one of items 13 to 19, which is a phase separation glass.
21. 20. The building material glass according to any one of items 13 to 19, which is a crystallized glass containing crystals.

22. 22. The building material glass according to any one of items 13 to 21, wherein a coating is applied to the back surface.
23. 23. The building material glass according to any one of items 13 to 22, which has a thickness of 30 mm or less.

The glass of the present invention has an average value of linear transmittance at a wavelength of 400 to 800 nm as low as 15% or less, so that the influence of color unevenness on the back surface can be suppressed. It is possible to make the color unevenness on the back of the glass visible through the glass less noticeable.

In addition, the glass of the present invention can adjust the color of the back surface of the glass that is visible through the glass with high accuracy when the average value of the total light transmittance at a wavelength of 400 to 800 nm is 4% or more.

Therefore, when the glass of the present invention is used for a housing or the like, the color unevenness on the back side of the glass is suppressed, and the appearance on the back side of the glass is adjusted with high accuracy and has an excellent design. Can do.

When tiles are used in the interior of tunnels or tunnels, if the glaze phase on the tile surface is chipped and peeled off, the ceramic substrate will be exposed, and will be easily soiled and difficult to remove. On the other hand, by using the glass for building materials of the present invention for interiors of tunnels or tunnels, even if the glass surface is scratched or chipped, the new surface is glass, so that it is difficult to get dirt and has excellent cleaning performance. At the same time, the reflection performance can be maintained.

FIG. 1 is a diagram showing the correlation between wavelength and linear transmittance. FIG. 2 is a diagram showing the results of testing whether the color unevenness on the back surface can be suppressed using the glasses of Examples 1 to 5. (A) shows Example 1, (b) shows Example 2, (c) shows Example 3, (d) shows Example 4, and (e) shows Example 5. FIG. 3 is a diagram showing the correlation between the wavelength and the total light transmittance. FIG. 4 is a diagram showing the correlation between the average total light transmittance and the saturation C (Δa ^* , Δb ^* ). FIGS. 5A to 5C are diagrams in which the glass of the present invention is used as a casing glass of a mobile phone. FIG. 5A is a perspective view, and FIGS. 5B and 5C are cross-sectional views taken along line AA of FIG. 5A.

[Glass]
Examples of the glass of the present invention include phase-separated glass (also called phase-separated glass) or crystallized glass.

(Phase separation glass)
Glass phase separation means that a single-phase glass is divided into two or more glass phases. Examples of the method for phase separation of glass include a method for heat-treating glass.

As the conditions for the heat treatment for phase separation of the glass, typically, a temperature 50 to 400 ° C. higher than the glass transition point is preferable. A temperature higher by 100 ° C. to 300 ° C. is more preferable. The time for heat treating the glass is preferably 1 to 64 hours, more preferably 2 to 32 hours. From the viewpoint of mass productivity, it is preferably 24 hours or less, and more preferably within 12 hours.

Whether the glass is phase-separated or not can be determined by SEM (scanning electron microscope). That is, when the glass is phase-separated, it can be observed that it is divided into two or more phases when observed with an SEM.

状態 Examples of the state of phase-separated glass include a binodal state and a spinodal state. The binodal state is a phase separation by a nucleation-growth mechanism and is generally spherical. The spinodal state is a state in which the phase separation is intertwined with each other in three dimensions with some degree of regularity.

In order to increase the surface compressive stress in the chemically strengthened layer having a surface compressive stress by ion-exchanging the phase-separated glass, the phase-separated glass subjected to the ion exchange treatment is preferably in a binodal state. In particular, it is preferable that a dispersed phase of other components rich in silica is present in the alkali-rich matrix.

In order to whiten the phase-separated glass, the average size of one phase in the phase-separated state or the average particle size of the dispersed phase in the phase-separated glass is preferably 50 to 2000 nm, and preferably 100 to 1000 nm. More preferred. Typically, it is 200 nm or more or 500 nm or less. The average particle size of the dispersed phase can be measured by SEM observation.

Here, the average size of one phase in the phase separation state is the average of the widths of the phases intertwined with each other in the spinodal state, and when one phase is spherical in the binodal state When the diameter of one phase is elliptical, it is the average value of the major axis and the minor axis. The average particle size of the dispersed phase is the average size in the binodal state.

Also, in order to whiten the phase-separated glass, it is preferable that the difference in refractive index between the dispersed phase particles in the phase-separated glass and the matrix around it is large.

Furthermore, the volume ratio of the dispersed phase particles in the phase-separated glass is preferably 10% or more, and more preferably 20% or more. Here, the volume ratio of the particles of the dispersed phase is estimated from the ratio of the dispersed particles by calculating the ratio of the dispersed particles distributed on the glass surface from the SEM observation photograph.

There are no particular restrictions on the method of producing the phase-separated glass, but for example, various amounts of various raw materials are prepared, heated to about 1500-1800 ° C. and melted, and then homogenized by defoaming, stirring, etc. Formed into a plate or the like by drawing, pressing, or roll-out, or cast into a block, and after slow cooling, processed into an arbitrary shape, then processed to phase separation and processed into the desired shape Then, an ion exchange process is performed.

In the present invention, the glass is melted, homogenized, molded, slowly cooled, or shaped without any special phase separation process in steps such as melting, homogenizing, molding, annealing, or shaping. What phase-divided glass by heat processing shall also be included in phase-separated glass, and in this case, the step of phase-separating the glass is included in the step of melting or the like.

The phase-separated glass preferably contains Na ₂ O. When the phase-separated glass contains Na ₂ O, the strength of the glass by the subsequent ion exchange treatment can be increased. The Na ₂ O content in the glass is preferably 1% or more. If it is less than 1%, it becomes difficult to form a desired surface compressive stress layer by ion exchange. Preferably it is 3% or more, More preferably, it is 4% or more. When Na ₂ O exceeds 17%, the weather resistance decreases. Preferably it is 14% or less, More preferably, it is 11% or less.

The phase-separated glass preferably contains SiO ₂ , Al ₂ O ₃ and MgO. When the phase-separated glass contains SiO ₂ , Al ₂ O ₃ and MgO, ion exchange is facilitated, and durability and strength are improved.

The content of SiO ₂ in the phase-separated glass is preferably 50 to 80%, more preferably 55 to 75%, and still more preferably 60 to 70%.

The content of Al ₂ O ₃ in the phase-separated glass is preferably 0 to 10%, more preferably 1 to 7%, and further preferably 2 to 5%. For example, the content of Al ₂ O ₃ is preferably 0 to 10%. Al ₂ O ₃ may or may not be contained, but when it is contained, the content is preferably 10% or less. Is the meaning.

The content of MgO in the phase-separated glass is preferably 0 to 30%, more preferably 5 to 25%, and even more preferably 10 to 20%.

The phase-separated glass preferably contains at least one selected from MgO, CaO, SrO and BaO. When the phase-separated glass contains at least one selected from MgO, CaO, SrO and BaO, the whiteness of the glass can be increased. The total amount is preferably 5 to 30%, more preferably 10 to 25%, still more preferably 12 to 20%.

The phase-separated glass preferably contains at least one selected from ZrO ₂ , P ₂ O ₅ and La ₂ O ₃ . When the phase-separated glass contains at least one selected from ZrO ₂ , P ₂ O ₅ and La ₂ O ₃ , the whiteness of the glass can be increased. The total amount is preferably 0.5 to 10%.

The content of ZrO ₂ in the phase-separated glass is preferably 0 to 5%, and more preferably 0.5 to 3%. The content of P ₂ O ₅ in the phase-separated glass is preferably 0 to 10%, more preferably 0.5 to 5%, and further preferably 1 to 4%.

The content of La ₂ O ₃ in the phase-separated glass is preferably 0 to 2%, more preferably 0.2 to 1%.

The phase-separated glass may contain K ₂ O. K ₂ O is a component for improving the meltability, and is a component for increasing the ion exchange rate in chemical strengthening to obtain a desired surface compressive stress and stress layer depth. In order to improve the meltability, the effect is small at less than 1%. Preferably it is 1% or more. In order to improve the ion exchange rate, it is preferably 2% or more, and typically 3% or more. When K ₂ O exceeds 9%, the weather resistance decreases. Preferably it is 7% or less, typically 6% or less.

(Crystallized glass)
Examples of the crystal glass include crystallized glass containing nepheline solid solution crystals. Crystallized glass containing nepheline solid solution crystals can be produced through heat treatment of the precursor as described in US Pat. No. 2,920,971. In the manufacture of crystallized glass containing nepheline solid solution crystals, the following steps (i) to (iii) are included.
(I) Melting a glass-forming batch that usually contains a nucleating agent.
(Ii) At the same time, the melt is cooled to a temperature lower than its transition range to form a glass having a desired shape.
(Iii) The glass is subjected to a prescribed heat treatment method to crystallize the glass.

The step (iii) is divided into the following two steps (iii-1) and (iii-2).
(Iii-1) First, the original glass is heated to a temperature within or slightly above the transition range to form nuclei in the glass. As conditions for the heat treatment for generating nuclei in the glass, the temperature is preferably 950 ° C. or lower, and more preferably 900 ° C. or lower. The heat treatment time is preferably 1 to 10 hours, more preferably 2 to 6 hours.
(Iii-2) The glass is heated to a higher temperature, sometimes higher than its softening point, to grow crystals on the nuclei formed in (iii-1). As conditions for the heat treatment for growing crystals, the temperature is preferably 850 to 1200 ° C., more preferably 900 to 1150 ° C. The heat treatment time is preferably 1 to 10 hours, more preferably 2 to 6 hours.

The crystallized glass containing nepheline solid solution crystals obtained by heat treatment under the conditions within the above range is easy to ion-exchange, and the crystallized glass is ion-exchanged to provide a high light shielding property suitable for the casing. Strength can be obtained.

A nepheline solid solution crystal is a crystal represented by the formula Na _8-x K _x Al ₈ Si ₈ O ₃₂ (where x varies in the range of 0 to 8). Nepheline solid solution crystals have high ion exchange efficiency, and high strength can be obtained in addition to light shielding properties that are more suitable for the housing by subjecting the crystallized glass containing the crystals to ion exchange treatment.

Also, the main crystal phase of the crystallized glass is preferably nepheline solid solution crystal. The main crystal phase of the crystallized glass is nepheline solid solution crystal, so that high ion exchange efficiency can be obtained, and the crystallized glass having the nepheline solid solution crystal as the main crystal phase is ion-exchanged so that it is more suitable for the casing. In addition to light shielding properties, high strength can be obtained.

The crystallized glass containing nepheline solid solution crystals preferably contains Na ₂ O. When the crystallized glass containing the nepheline solid solution crystal contains Na ₂ O, the strength of the crystallized glass by the subsequent ion exchange treatment can be increased. The content of Na ₂ O in the crystallized glass containing nepheline solid solution crystals is preferably 10 to 30%, more preferably 12 to 24%, and further preferably 15 to 20%.

SiO ₂ and Al ₂ O ₃ are the main components of nepheline solid solution and are essential. The content of SiO ₂ in the crystallized glass containing nepheline solid solution crystals is preferably 40 to 70%, more preferably 45 to 64%. The content of Al ₂ O ₃ in the crystallized glass containing nepheline solid solution crystals is preferably 8 to 28%, more preferably 15 to 25%, and still more preferably 20 to 24%.

In crystallized glass containing nepheline solid solution crystals, TiO ₂ is essential as a nucleation material.

The content of TiO ₂ in the crystallized glass containing nepheline solid solution crystals is preferably 4 to 12%, more preferably 5 to 10%.

The crystallized glass containing nepheline solid solution crystals may contain K ₂ O. K ₂ O is one of the components that form nepheline solid solution crystals, is a component that improves meltability, and is a component that increases the ion exchange rate in chemical strengthening. In order to improve the ion exchange rate, the effect is small at less than 1%. Preferably it is 2% or more. When K ₂ O exceeds 10%, the weather resistance decreases. Preferably it is 8% or less.

The crystallized glass containing nepheline solid solution crystals is preferably whitened. By forming the crystallized glass for housing of the present invention obtained by ion-exchange treatment of crystallized glass containing nepheline solid solution crystal having whitening and light-shielding properties, it is possible to reduce the light without providing a light-shielding means separately. A highly shielding housing that exhibits a white appearance at a low cost can be obtained. Moreover, the housing | casing provided with the designability is obtained.

The crystallized glass of the present invention is not limited to nepheline solid solution crystal, and crystallized glass such as crystallized glass containing β-quartz solid solution crystal and crystallized glass containing β-spodumene solid solution crystal is also used for the glass of the present invention. include.

Co, Mn, Fe, Ni, Cu, Cr, V, Zn, Bi, Er, Tm, Nd, Sm, Sn, Ce, Pr, Eu, Ag or Au are added to the glass of the present invention as coloring components. May be. When added, the addition amount is preferably 5% or less in terms of mol% based on oxide.

[Linear transmittance]
The glass of the present invention has an average value of linear transmittance (also referred to as parallel transmittance) at a wavelength of 400 nm to 800 nm of 15% or less, preferably 10% or less, and more preferably 5% or less. When the average value of the linear transmittance at a wavelength of 400 nm to 800 nm exceeds 15%, the color unevenness on the back surface of the glass visually recognized through the glass is easily noticeable.

The linear transmittance depends on the thickness of the glass, but the thickness of the glass of the present invention is the thickness of various products. The linear transmittance in the thickness of the corresponding product is defined as the linear transmittance in the present invention. *

The thickness of the glass of the present invention is 0.2 mm to 5 mm. In order to make the back surface color unevenness inconspicuous, it should be 0.2 mm or more. Preferably it is 0.5 mm or more, More preferably, it is 1 mm or more. In order to facilitate the color adjustment of the back surface of the glass and to reduce the weight of the glass, the thickness is set to 5 mm or less. Preferably it is 3 mm or less, More preferably, it is 2 mm or less.

In the glass of the present invention, the maximum value of linear transmittance at a wavelength of 400 nm to 800 nm is 35% or less, preferably 25% or less, and more preferably 15% or less. When the maximum value of the linear transmittance at a wavelength of 400 nm to 800 nm exceeds 35%, the color unevenness on the back surface of the glass that is visually recognized through the glass becomes conspicuous.

The average value of the linear transmittance at a wavelength of 400 nm to 800 nm can be obtained by measuring the linear transmittance T at a wavelength of 400 nm to 800 nm for each wavelength of 1 nm and using the following formula.

In the above formula, n is an integer of 400 to 800.

As for color unevenness on the back side of the glass, as will be described later in the examples, it is possible to test whether or not the pattern can be identified through the glass by placing the glass on a paper having a dot-like pattern imitating the color unevenness. it can.

The linear transmittance of glass at wavelengths of 400 nm to 800 nm can be measured by ordinary transmittance measurement.

[Total light transmittance]
By adjusting the permissible range of the perceived color difference in the glass, it is possible to adjust the color tone of the back surface of the glass viewed through the glass. In other words, when the measured tristimulus values XYZ are converted into UCS (uniform color space), it is possible to compare the magnitude of the perceived color difference with the distance between the coordinates of the two points using the L ^* a ^* b ^* color system. Can be expressed by a color difference value ΔE ^* ab obtained by the following equation.
ΔE ^* ab = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2

If the color tolerance is 0.8 or less, the color difference on the back side of the glass is hardly noticed. When ΔL ^* is constant, the saturation C (a ^* , b ^* ) calculated by the following equation is set to 0.8 or more, so that the color difference on the back of the glass seen through the glass can be slightly felt. And the color tone of the back surface of the glass can be adjusted with high accuracy.
Saturation C (Δa ^* , Δb ^* ) = [(Δa ^* ) ² + (Δb ^* ) ² ] ^1/2

Here, as shown in FIG. 4, the average value of the total light transmittance at wavelengths of 400 nm to 800 nm and the saturation C (Δa ^* , Δb ^* ) are in a proportional relationship. From the graph shown in FIG. 4, in order to set the saturation C (Δa ^* , Δb ^* ) to 0.8 or more, it is necessary to set the average value of the total light transmittance at wavelengths of 400 nm to 800 nm to 4% or more. Recognize.

The total light transmittance depends on the thickness of the glass, but the thickness of the glass of the present invention is the thickness of various products. The total light transmittance in the thickness of the corresponding product is defined as the total light transmittance in the present invention.

Therefore, the glass of the present invention has an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more, preferably 5% or more, more preferably 10% or more, and more preferably 20% or more. More preferably, it is particularly preferably 30% or more. When the average value of the total light transmittance at a wavelength of 400 nm to 800 nm is less than 4%, the saturation C (Δa ^* , Δb ^* ) is less than 0.8, and it is difficult to adjust the color of the back surface of the glass with high accuracy. Become. The higher the total light transmittance, the better. However, since the average value of the linear transmittance is 15% or less, the upper limit of the total light transmittance is usually 60%.

The average value of the total light transmittance at wavelengths of 400 nm to 800 nm can be obtained from the following formula by measuring the total light transmittance T ′ for each wavelength of 1 nm at wavelengths of 400 nm to 800 nm.

In the above formula, n is an integer of 400 to 800.

The total light transmittance of glass at a wavelength of 400 nm to 800 nm can be measured with a spectrophotometer or the like.

In order to set the average value of the linear transmittance at a wavelength of 400 nm to 800 nm to 15% or less and the average value of the total light transmittance at a wavelength of 400 nm to 800 nm to 4% or more, the composition of glass, heat treatment conditions (for example, phase separation glass) In the case of a crystallized glass, or in the case of crystallized glass, it can be appropriately adjusted.

Specifically, for example, when the glass is a phase separation glass, the average value of the linear transmittance at a wavelength of 400 nm to 800 nm is set to 15% or less, and the wavelength of 400 nm to The average value of the total light transmittance at 800 nm can be 4% or more.
(Glass composition)
In terms of mol%, preferably, SiO ₂ is 50 to 70%, Al ₂ O ₃ is 1 to 6%, the total amount of MgO, CaO and BaO is 0 to 20%, Na ₂ O is 1 to 15%, P ₂ O ₅ 0.5-5%, B ₂ O ₃ 0-5%, ZrO ₂ 0-5%.
(Phase separation processing conditions)
A temperature higher by 50 to 400 ° C. than the glass transition point is preferred. A temperature higher by 100 ° C to 300 ° C is more preferable. The time for heat treating the glass is preferably 1 to 64 hours, more preferably 2 to 32 hours. From the viewpoint of mass productivity, it is preferably 24 hours or less, and more preferably within 12 hours.

For example, when the glass is a crystallized glass, the average value of linear transmittance at a wavelength of 400 nm to 800 nm is set to 15% or less depending on the glass composition and crystallization conditions in the following range, and the total light at a wavelength of 400 nm to 800 nm is set. The average value of the transmittance can be 4% or more.
(Glass composition)
In terms of mol%, SiO ₂ is 45 to 60%, Al ₂ O ₃ is 15 to 28%, Na ₂ O is 10 to 20%, K ₂ O is 1 to 10%, and TiO ₂ is 5 to 10%.
(Crystallization conditions)
(1) First, as a heat treatment condition in which the original glass is heated to a temperature within or slightly higher than the transition range to generate nuclei in the glass, the temperature is preferably 950 ° C. or less, and 900 ° C. or less. It is more preferable that The heat treatment time is preferably 1 to 10 hours, more preferably 2 to 6 hours.
(2) Heat treatment conditions for heating the glass to a higher temperature, sometimes higher than its softening point, to grow crystals on the nuclei formed in (1) are: 850-1200 ° C. Preferably, the temperature is 900 to 1150 ° C. The heat treatment time is preferably 1 to 10 hours, more preferably 2 to 6 hours.

The present invention includes a glass sorting method as another embodiment. For example, when the average value of the linear transmittance at a wavelength of 400 nm to 800 nm of the glass is 15% or less and the average value of the total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more, color unevenness on the back surface of the glass is suppressed. At the same time, the saturation C (Δa ^* , Δb ^* ) can be set to 0.8 or more, and it is determined that the glass can be adjusted with high accuracy in color on the back surface of the glass. it can.

[Chemical strengthening]
The glass of the present invention may be chemically strengthened by ion exchange treatment to have high strength. Chemical strengthening is a method of increasing the strength of glass by forming a compressive stress layer on the glass surface. Specifically, alkali metal ions (typically Li ions, Na ions) having a small ion radius on the surface of the glass plate by ion exchange at a temperature below the glass transition point are converted to alkali ions (typically Is a process of exchanging Na ions or K ions for Li ions and K ions for Na ions.

The chemical strengthening method is not particularly limited as long as Li ₂ O or Na ₂ O on the glass surface layer and Na ₂ O or K ₂ O in the molten salt can be ion-exchanged. For example, heated potassium nitrate (KNO ₃ ) A method of immersing glass in molten salt.

The conditions for forming a chemically strengthened layer having a desired surface compressive stress (surface compressive stress layer) on the glass vary depending on the thickness of the glass, but the temperature condition is preferably 350 to 550 ° C., preferably 400 to More preferably, it is 500 degreeC. The chemical strengthening time is preferably 1 to 144 hours, and more preferably 2 to 24 hours. Examples of the molten salt include KNO ₃ and NaNO ₃ . Specifically, for example, it is typical to immerse the glass in a KNO ₃ molten salt at 400 to 550 ° C. for 2 to 24 hours.

Chemically tempered glass has a compressive stress layer on the surface by ion exchange treatment. In the manufacture of glass used for housing applications, a polishing step may be performed when the glass is flat. In the glass polishing process, the grain size of polishing abrasive grains used for the final stage polishing is typically 2 to 6 μm, and such abrasive grains ultimately cause the glass surface to have a maximum of 5 μm micron. It is thought that a crack is formed.

In order to make the effect of improving the strength by chemical strengthening effective, it is preferable to have a surface compressive stress layer deeper than the microcracks formed on the glass surface, and the depth of the surface compressive stress layer generated by chemical strengthening is 6 μm. The above is preferable. In addition, if a scratch exceeding the depth of the surface compressive stress layer is caused during use, it leads to glass breakage. Therefore, the surface compressive stress layer is preferably deeper, more preferably 10 μm or more, more preferably 20 μm or more, typically 30 μm or more.

On the other hand, if the surface compressive stress layer becomes too deep, the internal tensile stress increases and the impact at the time of failure increases. That is, it is known that when the internal tensile stress is large, the glass tends to break up into pieces when it breaks. As a result of experiments by the present inventors, it has been found that in a glass having a thickness of 2 mm or less, scattering at the time of breakage becomes significant when the depth of the surface compressive stress layer exceeds 70 μm.

Therefore, in the chemically strengthened glass, the depth of the surface compressive stress layer is preferably 70 μm or less. When chemically tempered glass is used as the housing, depending on the electronic equipment to be packaged, the depth of the surface compressive stress layer should be kept thin for safety, for example, in applications such as panels that have a high probability of contact scratches on the surface. More preferably, it is 60 μm or less, more preferably 50 μm or less, and typically 40 μm or less.

The depth of the surface compressive stress layer of the chemically strengthened glass can be measured using an EPMA (electron probe micro analyzer) or a surface stress meter (for example, FSM-6000 manufactured by Orihara Seisakusho).

For example, when ion exchange is performed between the sodium component of the glass surface layer and the potassium component in the molten salt in the ion exchange treatment, the potassium ion concentration analysis in the depth direction of the crystallized glass is performed with EPMA, and the potassium ion obtained by the measurement The diffusion depth is regarded as the depth of the surface compressive stress layer.

Further, when ion exchange is performed between the lithium component of the glass surface layer and the sodium component in the molten salt in the ion exchange treatment, the sodium ion concentration analysis in the depth direction of the glass is performed by EPMA, and the sodium ion diffusion depth obtained by the measurement is measured. This is regarded as the depth of the surface compressive stress layer.

Also, it is possible to apply surface compressive stress due to thermal expansion difference by thinly coating the surface with glass having a smaller thermal expansion coefficient than chemically strengthened glass. If clear glass is used, the effect of improving the aesthetics due to the reflection of the front and back surfaces of the coated glass can be obtained.

[Usage]
The glass of the present invention is packaged, for example, on an electronic device. On the outer surface of the mobile phone, a display device made up of a liquid crystal panel or an organic EL display and an operation device made up of buttons, or a display device such as a touch panel integrated with an operation device is arranged on one outer surface. The frame material surrounds the periphery. The other outer surface is composed of a panel. And there exists a frame material in the thickness part of the apparatus between one outer surface and the other outer surface. The frame material and the frame material, or the panel and the frame material may be configured integrally.

The glass of the present invention can be used for any of the aforementioned frame materials, panels, and frame materials. In addition, these shapes may be flat or curved, and may be a concave shape or a convex shape in which the frame material and the frame material, or the panel and the frame material are integrated. Good.

A light source of a display device provided in an electronic device is configured to emit white light such as a light emitting diode, an organic EL, or a CCFL. Some organic EL displays include a light emitting element that emits white light or the like without using the light source. If these white light leaks out of the device through the chemically strengthened glass, the appearance will deteriorate. Therefore, it is preferable that the glass has a characteristic of reliably blocking white light.

The glass of the present invention may be formed not only in a flat plate shape but also in a concave shape or a convex shape. In this case, you may press-form in the state which reheated and melt | dissolved the glass shape | molded in the flat plate or the block. Moreover, you may shape | mold into a desired shape by what is called a direct press method which flows out and press-molds a molten glass directly on a press die. Further, a portion corresponding to a display device or a connector of an electronic device may be processed simultaneously with press molding, or may be subjected to cutting or the like after press molding.

The reason why the glass of the present invention is used for the housing is as follows. The glass obtained by the production method of the present invention has a white appearance as particles such as a dispersed phase in the glass diffuse and reflect and scatter light. The glass of the present invention makes white light transmitted through the glass opaque by utilizing the scattering of light from the glass, and makes it difficult to recognize color unevenness on the glass back surface on the glass surface side.

FIGS. 5A to 5C illustrate an example in which the glass of the present invention is used as a casing glass constituting at least a part of the casing body in a mobile phone. FIG. 5A is a perspective view of the mobile phone 10 in which the casing glass 12 is arranged on a part of the outer surface side of the casing 11, and FIGS. 5B and 5C are FIGS. ) In FIG. 5B and FIG. 5C, the hatched portion from the upper right to the lower left is a portion constituting the inner surface side of the housing 11, and It may be glass or other than the glass of the present invention.

Examples of materials other than the glass of the housing 11 include metals, plastics, and ceramics.

As shown in FIG. 5C, the housing glass 12 may have a functional layer 13 between a surface (back surface) facing the outer surface of the housing 11 and another surface in the housing. Good. Examples of the functional layer 13 include a print portion, a print layer, a coated paint layer, a sprayed paint layer, and an adhesive layer. Here, what does not cause a plate is referred to as printing, and what causes a plate is referred to as printing. The printing layer includes full surface printing and partial printing.

The effect of suppressing color unevenness by the glass of the present invention is enhanced when the housing glass 12 and the functional layer 13 are integrated. Specifically, the case where the layer printed on the housing glass 12 constitutes at least a part of the functional layer 13 is preferable. When the layer is printed directly on the housing glass 12 or the entire surface is printed on the housing glass 12. And the like are more preferable. Further, in the functional layer 13, for example, when printing is performed on the surface facing the housing glass 12 of the portion constituting the inner surface side of the housing 11, the functional layer is formed on the portion constituting the inner surface side of the housing 11. 13 includes a case where the housing glass 12 is used on the functional layer 13.

Due to the color unevenness and color of the back surface of the glass in the housing 11 or the functional layer 13, the color unevenness and color of the back surface of the glass in the housing 11 that is visually recognized through the housing glass 12 change. Appearance changes. In the glass of the present invention, the average value of the linear transmittance at a wavelength of 400 to 800 nm is as low as 15% or less, so that the surface of the housing glass 12 facing the outer surface of the housing 11 and the back side of the housing 11 are configured. The color unevenness is covered with the portion to be covered, that is, on the back surface of the housing glass 12, and the average value of the total light transmittance at a wavelength of 400 to 800 nm is 4% or more, so that the color can be adjusted with high accuracy. Therefore, it is possible to obtain the casing 11 having an excellent design appearance in which color unevenness visually recognized through the casing glass 12 is suppressed and the color is adjusted with high accuracy.

Further, the chemically strengthened glass obtained by subjecting the glass of the present invention to ion exchange treatment is characterized by excellent mechanical strength and the like. Therefore, it can be preferably used for a white glass casing of a portable electronic device such as a mobile phone that requires high strength to the casing.

The glass of the present invention can be suitably used for portable electronic devices. A portable electronic device is a concept that encompasses communication devices or information devices that can be carried around.

Examples of communication devices include mobile phones, PHS (Personal Handy-phone System), smartphones, PDAs (Personal Data Assistance) and PNDs (Portable Navigation Devices, portable car navigation systems) as communication terminals, and broadcast receivers. Mobile radio, mobile TV, one-seg receiver and the like.

Examples of information devices include digital cameras, video cameras, portable music players, sound recorders, portable DVD players, portable game machines, notebook computers, tablet PCs, electronic dictionaries, electronic notebooks, electronic book readers, portable printers, and mobile phones. For example, a scanner. In addition, it is not limited to these for illustration.

By using the glass of the present invention for these portable electronic devices, portable electronic devices having high design properties can be obtained.

Note that the glass of the present invention having high design properties can be applied to a desktop personal computer, a large TV, a building material, furniture, a home appliance, or the like.

As glass for building materials, the thickness is 0.5 mm or more, the average value of linear transmittance at a wavelength of 400 nm to 800 nm is 15% or less, and the average value of total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more. Preferably there is.

In order to improve the chemical durability, the glass for building materials preferably contains 0 to 25%, more preferably 1 to 15% of Al ₂ O ₃ in terms of mole percentage based on oxide. More preferably, the content is 2 to 10%.

In order to increase the whiteness, the glass for building materials preferably contains 0.5 to 10% of ZrO ₂ + P ₂ O ₅ + La ₂ O ₃ in terms of oxide-based mole percentage, and preferably 1 to 8%. The content is more preferably 2 to 6%.

The glass for building materials preferably contains 0 to 15% of Na ₂ O, more preferably 3 to 15% in terms of oxide-based mole percentage, in order to improve the solubility in melting of the glass. The content is preferably 4 to 13%, more preferably 5 to 12%.

Examples of the glass for building materials include glass for tunnels or tunnel interiors. “Anti-road” refers to a passage made underground, mainly used for mining in mines. A “tunnel” is a man-made or naturally-formed civil engineering structure that passes from the ground to the destination underground, under the sea, or in the mountains, and in the axial direction compared to the height or width of the cross section. An elongated space.

Artificial tunnels include, for example, roads or railways (railways) constructed for the purpose of laying lifelines such as water or electric wires (for example, common trenches), mining minerals or storing or transporting materials (for example, , Mountain tunnel).

The thickness of the building glass is preferably 0.5 mm or more, more preferably 1 mm or more, still more preferably 2 mm or more, and particularly preferably 3 mm or more. By setting the thickness to 0.5 mm or more, sufficient strength can be obtained. Moreover, from a viewpoint of weight reduction, it is preferable that it is 30 mm or less, More preferably, it is 20 mm or less, More preferably, it is 15 mm or less, Most preferably, it is 10 mm or less.

When tiles are used in the interior of tunnels or tunnels, if the glaze phase on the tile surface is chipped and peeled off, the ceramic substrate will be exposed, and will be easily soiled and difficult to remove. In contrast, according to the present invention, white glass is used for interiors of tunnels or tunnels, so that even if scratches or chips on the glass surface occur, the new surface is glass, so that it is difficult to get dirt and cleaning performance. In addition, the reflection performance can be maintained.

Moreover, the glass for building materials of the present invention is superior in strength compared to tiles with a glaze applied to ceramic substrates, even if the glass surface is scratched or chipped, even if the glass surface is scratched or chipped. Since the new surface is glass, the strength can be maintained.

Furthermore, according to the glass for building materials of the present invention, it is possible to obtain an interior material having design properties by using glass having excellent workability as an interior material of a tunnel or a tunnel.

The glass for building materials of the present invention can be directly attached to the wall surface with an adhesive or the like. In addition, a glass panel for building material in which a plurality of white glasses are attached to a cement plate or a metal plate can be installed on the wall surface. Moreover, you may fix with jigs, such as metal and ceramics, instead of sticking directly to a wall surface. Moreover, when fixing with a jig, you may hold | maintain at the edge of glass and you may fix using the hole opened in the white glass surface.

The glass for building materials of the present invention may be laminated with a resin or the like in order to prevent it from being broken and scattered when a vehicle or the like collides, or a laminated glass using a resin or the like in an intermediate layer between glass and glass. . In this case, the glass on the back surface may be white glass or transparent glass.

The glass for building materials of the present invention may be polished on the end side for easy handling or prevention of strength reduction due to cracks or the like.

The size of the glass for building material of the present invention is preferably such that the short side or the short diameter is 30 mm or more, more preferably 40 mm or more, still more preferably 100 mm or more, and particularly preferably 500 mm or more. By setting it to 30 mm or more, it is possible to prevent an increase in the number of sheets to be installed and improve work efficiency. Further, the length of the long side or the long diameter is preferably 3000 mm or less, more preferably 2000 mm or less, and still more preferably 1000 mm or less. By setting it to 3000 mm or less, it can be easily handled.

The glass for building materials of the present invention preferably has a density of 3.0 g / cm ³ or less, more preferably 2.8 g / cm ³ or less. When the density is 3.0 g / cm ³ or less, the weight can be reduced.

The glass for building materials of the present invention preferably does not contain filler mixed glass. When the filler mixed glass is contained, the mixing amount is preferably 1% or less. Here, the filler is a ceramic powder or a crystal powder, and the filler mixed glass is obtained by mixing a filler with glass and heat-molding it. In addition, the crystal | crystallization which precipitated from the uniform glass obtained by fuse | melting is not contained in a filler.

Examples of the filler include aluminum nitride, zirconia oxide, zircon, and titanium oxide. The filler-mixed glass is easy to contain bubbles, and the strength may be reduced by stress due to the difference in thermal expansion between the filler and the mother glass. By not containing the filler mixed glass, the strength of the glass can be improved.

Building materials for glass of the present invention preferably has acid resistance (20 hours 0.1 M HCl treatment at 90 ° C.) is 2 mg / cm ² or less, more preferably 1 mg / cm ² or less, 0.5 mm More preferably, it is as follows. Improves resistance to sulfur oxide (SO _X ) or nitrogen oxide (NO _X ) contained in exhaust gas when acid resistance (0.1 M HCl treatment at 90 ° C. for 20 hours) is 2 mg / cm ² or less can do.

The glass for building materials of the present invention preferably has an alkali resistance (0.1 M NaOH treatment at 90 ° C. for 20 hours) of 2 mg / cm ² or less, and more preferably 1 mg / cm ² or less. When the alkali resistance (0.1 M NaOH treatment at 90 ° C. for 20 hours) is 2 mg / cm ² or less, it is possible to improve resistance to alkali components eluted from the concrete or the like used on the wall surface.

The glass for building materials of the present invention preferably has a bending strength of 60 MPa or more, more preferably 80 MPa or more. When the bending strength is 60 MPa or more, sufficient strength against the deformation of the wall surface due to the collision of the vehicle or deterioration over time can be obtained. The bending strength is measured by a three-point bending test.

The glass for building materials of the present invention is typically plate-shaped. Moreover, you may shape | mold not only flat form but curved surface form. In this case, the glass formed into a flat plate or a block may be reheated and softened in its own weight, or may be press-molded. Moreover, you may shape | mold into a desired shape by what is called a direct press method which flows out and press-molds a molten glass directly on a press die.

The surface of the glass for building material of the present invention may be a flat surface or an uneven pattern. The uneven pattern may be sandwiched between rollers in which the glass is soft and the surface is uneven, or the uneven pattern may be formed by pressing. Further, the surface may be a mirror surface, or may be ground glass by polishing powder or etching. Moreover, the glass for building materials of this invention may be apply | coated with the coating material on the back surface.

The glass for building materials of the present invention is typically not chemically strengthened, but may be chemically strengthened or physically strengthened. By strengthening, the strength can be further increased.

[Manufacture of glass]
(Examples 1 to 4)
After the raw materials having the compositions shown in Table 1 were melted at 1550 to 1650 ° C. and annealed at 650 to 730 ° C., the samples were subjected to the heat treatment shown in Table 1, and the glass was phase-separated by SEM. The obtained glass was polished to obtain glasses of Examples 1 to 4.

(Example 5)
The glass raw material shown in Table 1 was put into a platinum crucible, melted at 1550 ° C., defoamed and homogenized, poured into a mold, and gradually cooled at 700 ° C. to obtain a glass block. The obtained glass was put into a resistance heating type electric furnace at 850 ° C., held for 4 hours for crystal nucleation, held at 1100 ° C. for 4 hours, and then cooled to room temperature at a cooling rate of 1 ° C. per minute. Crystallized glass was obtained by cooling. The obtained glass was polished to obtain the glass of Example 5.

Examples 2 to 4 are examples, and examples 1 and 5 are comparative examples.

(1) Linear transmittance (%)
With respect to the linear transmittance of the glass, a linear transmittance with a wavelength of 400 to 800 nm was obtained with a spectrophotometer U-4100 (manufactured by Hitachi High-Tech) using a glass having a thickness shown in Table 2 whose upper and lower surfaces were mirror-finished. . The results are shown in Table 2 and FIG.

The average value of the linear transmittance at a wavelength of 400 nm to 800 nm was obtained by measuring the linear transmittance T at a wavelength of 400 nm to 800 nm for each wavelength of 1 nm and using the following formula.

In the above formula, n is an integer of 400 to 800.

(2) Color unevenness test The glass of Examples 1 to 5 was placed on a paper on which a dot-like pattern simulating color unevenness was printed, and it was examined whether the dot-like pattern could be visually recognized through the glass. As a result, the case where the dot-like pattern was visible was set as “X”, and the case where it was not visible was set as “◯”. The results are shown in Table 2 and FIG. In FIG. 2, (a) shows Example 1, (b) shows Example 2, (c) shows Example 3, (d) shows Example 4, and (e) shows Example 5.

(3) Total light transmittance (%)
The total light transmittance of the glass was measured using an ultraviolet-visible near-infrared spectrophotometer LAMBDA 950 (manufactured by PerkinElmer) using a glass having a thickness shown in Table 2 whose upper and lower surfaces were mirror-finished. The light transmittance was acquired. The results are shown in Table 2 and FIG.

(4) Saturation The L ^* value indicating brightness and the chromaticity (a ^* , b ^* ) values indicating hue and saturation are standardized by the CIE (International Commission on Illumination), and in JIS (JISX8729) in Japan. Based on the standardized L ^* a ^* b ^* color system measurement, measurement was performed with a color meter (manufactured by Konica Minolta Co., Ltd .: trade name Color Colorimeter CR-400) at a light source D65 and a viewing angle of 2 °. The glasses of Examples 1 to 5 were measured on plates having L ^* values, a ^* values, and b ^* values shown as the back colors in Table 2, respectively. From the obtained a ^* value and b ^* value, the saturation C was calculated from the following equation.
Saturation C (Δa ^* , Δb ^* ) = [(Δa ^* ) ² + (Δb ^* ) ² ] ^1/2
Δa ^* is Δa ^* = a ^* (max) −a ^* (min), and Δb ^* is Δb ^* = b ^* (max) −b ^* (min).

The results are shown in Table 2. FIG. 4 shows a graph plotted with the average total light transmittance as the horizontal axis and the saturation C (Δa ^* , Δb ^* ) as the vertical axis.

As shown in Table 2 and FIG. 2, since the average value of the linear transmittance at a wavelength of 400 nm to 800 nm of the glass is 15% or less, the effect of covering the color unevenness on the background of the glass and making it less noticeable is obtained. I found out that

Further, as shown in FIG. 4, it was found that the average value of the total light transmittance at a wavelength of 400 nm to 800 nm of the glass and the saturation C (Δa ^* , Δb ^* ) are in a proportional relationship. From the results shown in FIG. 4, the saturation C (Δa ^* , Δb ^* ) can be set to 0.8 or more by setting the average value of the total light transmittance at a wavelength of 400 nm to 800 nm of the glass to 4% or more. It has been found that it is possible to adjust the color of the back of the glass with high accuracy.

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 November 29, 2012 (Japanese Patent Application No. 2012-261314), which is incorporated by reference in its entirety.

Claims

Glass with an average linear transmittance of 15% or less at a wavelength of 400 nm to 800 nm and an average value of total light transmittance of 4% or more at a wavelength of 400 nm to 800 nm.
The glass according to claim 1, wherein the maximum value of linear transmittance at a wavelength of 400 nm to 800 nm is 35% or less, and the minimum value of total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more.
The glass according to claim 1, which is a phase separation glass.
The glass according to claim 1 or 2, which is a crystallized glass containing crystals.
The glass according to any one of claims 1 to 4, which has a thickness of 0.2 to 5 mm.
A casing glass constituting at least a part of a casing, wherein an average value of linear transmittance at a wavelength of 400 nm to 800 nm is 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm is 4% or more The housing glass.
The housing glass according to claim 6, wherein the housing glass has a functional layer on a surface facing a housing outer surface.
The casing glass according to claim 7, wherein the layer printed on the casing glass constitutes at least a part of the functional layer.
A casing made of at least a part of glass, wherein the glass has an average value of linear transmittance at a wavelength of 400 nm to 800 nm of 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more The housing that is.
The housing according to claim 9, wherein at least a part of the outer surface portion is the glass, and the functional layer is provided on a surface of the glass facing the outer surface of the housing.
The housing according to claim 10, wherein the functional layer includes a layer printed on the glass.
An information terminal comprising the casing according to any one of claims 9 to 11.
A glass for building materials having a thickness of 0.5 mm or more, an average value of linear transmittance at a wavelength of 400 nm to 800 nm of 15% or less, and an average value of total light transmittance at a wavelength of 400 nm to 800 nm of 4% or more.
The building glass according to claim 13, containing 0 to 25% of Al 2 O 3 in terms of a molar percentage on an oxide basis.
The glass for building materials according to claim 13 or 14, containing 0.5 to 10% of ZrO 2 + P 2 O 5 + La 2 O 3 in terms of mole percentage based on oxide.
The glass for building materials according to any one of claims 13 to 15, which contains 0 to 15% of Na 2 O in terms of mass percentage based on oxide.
The building glass according to any one of claims 13 to 16, having a density of 3.0 g / cm 3 or less.
The building material glass according to any one of claims 13 to 17, which does not contain filler mixed glass.
The building material glass according to any one of claims 13 to 18, which is used for interiors of tunnels or tunnels.
The glass for building materials according to any one of claims 13 to 19, which is a phase separation glass.
The building glass according to any one of claims 13 to 19, which is a crystallized glass containing crystals.
The building glass according to any one of claims 13 to 21, wherein a coating is applied to the back surface.
The glass for building materials according to any one of claims 13 to 22, wherein the glass has a thickness of 30 mm or less.