Glass

Abstract

To provide a glass having a colored layer.SOLUTION: A glass includes a colored layer, the colored layer includes Ag as a glass component, and the maximum transmittance of the colored layer in the visible light region is 20% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to glass having a colored layer. [Background technology]

[0002] Glass having a colored portion can be used for various applications, such as glass articles such as daily necessities, Buddhist altar implements, ornaments, jewelry, works of art, exteriors of small electronic devices, and optical elements such as lenses, cover glass, and encoders. In such glass, it is sometimes required that the transmittance of the colored portion is sufficiently reduced while the non-colored portion has sufficient transparency.

[0003] As a method for coloring glass, a method is known in which Ag (silver) is introduced into glass to partially color the glass yellow, for colored glass such as stained glass. Patent Document 1 discloses a cover glass for a display device into which Ag (silver) is introduced using a molten salt. In Patent Document 1, antibacterial properties are imparted to the glass by introducing Ag (silver). However, Patent Document 1 aims to obtain a cover glass with high transparency and visible light transmittance, and does not obtain glass having a colored portion, i.e., a portion with sufficiently reduced transmittance.

[0004] Patent Document 2 discloses glass having a colored layer. However, the glass of Patent Document 2 contains Ti ions, Nb ions, W ions, or Bi ions as a glass component, so that the non-colored portion may not have sufficient transparency. In addition, the glass of Patent Document 2 needs to contain Ti ions or the like as a glass component in order to form a colored layer, so that the technology of Patent Document 2 may not be applicable to the production of glass with a low refractive index. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication 2011-133800 [Patent Document 2] Patent Publication No. 2022-40936 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide glass having a colored layer. [Means for solving the problem]

[0007] The gist of the present invention is as follows. (1) Having a colored layer, The colored layer contains Ag as a glass component, The colored layer has a maximum transmittance of 20% or less in the visible light region.

[0008] (2) An optical glass comprising the glass described in (1) above.

[0009] (3) An optical element comprising the glass according to (1) above. Effect of the Invention

[0010] According to the present invention, a glass having a colored layer can be provided. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a plate glass having a colored layer formed on one side thereof. [Diagram 2] FIG. 2 is a schematic diagram of a plate glass having colored layers formed on both sides. [Diagram 3] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition I obtained in Example 1-1. [Figure 4(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition I obtained in Example 1-2. [Figure 4 (2)]1 is a graph showing the transmittance of a non-colored portion of a glass sample having composition I obtained in Example 1-2. [Figure 5(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition II obtained in Example 2-1. [Figure 5 (2)] 1 is a graph showing the change in Ag content in the thickness direction of the colored layer of the glass sample having composition II obtained in Example 2-1. The right end of the graph is the surface of the glass sample, and the depth in the thickness direction of the glass sample increases as one moves to the left on the graph (i.e., in the direction of the arrow). [Figure 5 (3)] 1 is an SEM image of a cross section of a glass sample having composition II obtained in Example 2-1. The glass sample appears white to gray, and the colored layer appears whiter. [Figure 6(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition II obtained in Example 2-2. [Figure 6 (2)] 1 is a graph showing the change in Ag content in the thickness direction of the colored layer of the glass sample having composition II obtained in Example 2-2. The right end of the graph is the surface of the glass sample, and the depth in the thickness direction of the glass sample increases as one moves to the left on the graph (i.e., in the direction of the arrow). [Figure 6 (3)] 1 is an SEM image of a cross section of a glass sample having composition II obtained in Example 2-2. The glass sample appears white to gray, and the colored layer is observed as white. [Figure 7(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition II obtained in Example 2-3. [Figure 7(2)] 1 is a graph showing the transmittance of a non-colored portion for a glass sample having composition II obtained in Example 2-3. [Figure 8(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition II obtained in Example 2-4. [Figure 8 (2)]1 is a graph showing the transmittance of a non-colored portion of a glass sample having composition II obtained in Example 2-4. [Figure 9] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition III obtained in Example 3-1. [Figure 10(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition III obtained in Example 3-2. [Figure 10(2)] 1 is a graph showing the change in Ag content in the thickness direction of the colored layer of the glass sample having composition III obtained in Example 3-2. The right end of the graph is the surface of the glass sample, and the depth in the thickness direction of the glass sample increases as one moves to the left on the graph (i.e., in the direction of the arrow). [Figure 11(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition III obtained in Example 3-3. [Figure 11 (2)] 1 is a graph showing the change in Ag content in the thickness direction of the colored layer of the glass sample having composition III obtained in Example 3-3. The right end of the graph is the surface of the glass sample, and the depth in the thickness direction of the glass sample increases as one moves to the left on the graph (i.e., in the direction of the arrow). [Figure 11 (3)] 1 is an SEM image of a cross section of a glass sample having composition III obtained in Example 3-3. The glass sample appears white to gray, and the colored layer is observed as white. [Figure 12(1)] 1 is a graph showing the transmittance of a portion having a colored layer for a glass sample having composition IV obtained in Example 4. [Figure 12 (2)] 1 is a graph showing the transmittance of a non-colored portion of a glass sample having composition IV obtained in Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In this embodiment, the glass according to the present invention will be described based on the content ratio of each component expressed in cationic %. Therefore, hereinafter, in each content, "%" means "cationic %" unless otherwise specified. The cationic % expression refers to a molar percentage when the total content of all cationic components is taken as 100%. In addition, the total content refers to the total amount of the contents of multiple cationic components (including the case where the content is 0%).

[0013] The content of the glass component can be quantified by known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The content of Ag (silver) in the colored layer can be quantified by scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX) and fluorescent X-ray analysis (XRF). In this specification and the present invention, the content of a component being 0% means that the component is substantially not contained, and it is acceptable for the component to be contained at an unavoidable impurity level.

[0014] In this specification, unless otherwise specified, the refractive index refers to the refractive index nd at the d line of helium (wavelength 587.56 nm).

[0015] The Abbe number νd is used as a value that indicates the properties related to dispersion, and is expressed by the following formula: Here, nF is the refractive index at the F line (wavelength 486.13 nm) of blue hydrogen, and nC is the refractive index at the C line (656.27 nm) of red hydrogen. νd=(nd-1) / (nF-nC)

[0016] Hereinafter, embodiments of the present invention will be described in detail.

[0017] The glass according to this embodiment has a colored layer. The colored layer is a portion of the glass that is colored, and is preferably present in the form of a layer extending from the surface of the glass toward the inside.

[0018] In the glass according to this embodiment, the colored layer may be present so as to cover the entire glass surface (on the entire surface of the glass), or may be present so as to cover a portion of the glass surface (on a portion of the glass surface).

[0019] The colored layer is a portion having a low transmittance for light incident on the glass. Therefore, in the glass according to this embodiment, of the light incident on the glass, the light that enters the colored layer is absorbed partially or entirely, and the intensity of the transmitted light is attenuated compared to the light that does not enter the colored layer. In other words, the glass according to this embodiment can have portions with low transmittance and portions with high transmittance.

[0020] In the glass according to this embodiment, the colored layer can be removed by grinding or polishing. In the glass according to this embodiment, the transmittance of the glass after the colored layer is removed is greater than the transmittance before the colored layer is removed.

[0021] In the glass according to the present embodiment, the colored layer contains Ag as a glass component. The colored layer is colored by containing Ag. The higher the Ag content in the colored layer, the darker the colored layer is, but the degree of coloring varies depending on the glass composition, the forming conditions of the colored layer, and the like. Therefore, even if the Ag content in the colored layer is the same, the degree of coloring may vary depending on the glass composition, the forming conditions of the colored layer, and the like. The degree of coloring can be evaluated by transmittance or OD (optical density). When the Ag content exceeds a certain amount, the colored layer is darkly colored, and the transmittance of the colored layer may be close to 0%, and even if the Ag content is further increased, the degree of coloring may not be evaluated by the transmittance. It is preferable that the portion where the colored layer is not formed (hereinafter, sometimes referred to as the non-colored portion) does not substantially contain Ag.

[0022] In the glass according to this embodiment, whether or not the colored layer contains Ag can be evaluated by scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX), fluorescent X-ray analysis (XRF), etc. The Ag concentration in the colored layer is not particularly limited and is preferably 0.01 mass% or more, and further, the lower limit of the Ag concentration may be 0.03 mass%, 0.05 mass%, 0.08 mass%, 0.10 mass%, 0.30 mass%, 0.50 mass%, or 0.80 mass%.

[0023] In the glass according to this embodiment, the maximum transmittance of the colored layer in the visible light region is 20% or less. The maximum transmittance of the colored layer in the visible light region is preferably 15% or less, more preferably 10% or less, 5% or less, 3% or less, 2% or less, and 1% or less in that order. The transmittance can be reduced by deeply coloring the colored layer. On the other hand, the maximum transmittance of the non-colored visible light region is not particularly limited, but is preferably 70% or more, more preferably 80% or more. Here, the visible light region refers to a wavelength range of 380 nm to 780 nm.

[0024] When the glass according to the present embodiment is composed of a colored layer and a non-colored portion having a high transmittance in the visible light region, the transmittance of the colored layer is low, whereas the transmittance of the non-colored portion is high. In measuring the transmittance, when the measurement light passes through both the colored layer and the non-colored portion, the transmittance of the non-colored portion is sufficiently high, so that the transmittance of the colored layer becomes dominant.

[0025] In the glass according to this embodiment, the thickness of the colored layer is not particularly limited, but may be 0.1 μm to 150 μm. In addition, the width of the colored layer when viewed from above the glass is not particularly limited, but may be 0.1 μm to 100 μm. By setting the thickness and width of the colored layer within the above ranges, the clarity of the shape of the colored layer can be improved.

[0026] (OD) OD (optical density) is optical density or optical concentration, and is expressed as a negative value of the common logarithm of the ratio of incident light intensity I0 to transmitted light intensity I, as shown in the formula below. OD=-log 10 (I / I o )

[0027] When the glass according to the present embodiment is composed of a colored layer and a non-colored portion having a high transmittance in the visible light region, the OD of the colored layer is large, while the OD of the non-colored portion is small. In measuring the OD, when the measuring light passes through both the colored layer and the non-colored portion, the OD of the non-colored portion is sufficiently small, so that the OD of the colored layer becomes dominant.

[0028] In the glass according to this embodiment, the OD at a wavelength of 780 nm of the portion having the colored layer is preferably 0.5 or more, more preferably 0.75 or more, and even more preferably 1.0 or more, while the OD at a wavelength of 780 nm of the non-colored portion is preferably 0.2 or less, more preferably 0.15 or less, and even more preferably 0.1 or less.

[0029] In the glass according to this embodiment, the OD at a wavelength of 1100 nm of the portion having the colored layer is preferably 0.5 or more, more preferably 0.75 or more, and even more preferably 0.9 or more, while the OD at a wavelength of 1100 nm of the non-colored portion is preferably 0.2 or less, more preferably 0.15 or less, and even more preferably 0.1 or less.

[0030] In addition, when a glass has two opposing surfaces and a colored layer is provided on both surfaces, the OD is approximately twice as large as when the same colored layer is provided on only one surface.

[0031] In the glass according to this embodiment, the OD decreases with increasing wavelength in the wavelength range from the visible light region to the near infrared region. Therefore, in the portion having the colored layer, the OD at a wavelength of 780 nm is greater than the OD at a wavelength of 1100 nm.

[0032] Therefore, when there is a wavelength range to be shielded, the OD is designed to be high at the wavelength on the long wavelength side in that wavelength range. When designing a glass that shields only visible light, the OD may be set to be high at the long wavelength side of the visible light range (for example, 780 nm). To set the OD to be high at the long wavelength side of the visible light range (for example, 780 nm), for example, the Ag content may be adjusted, and the hydrogen concentration, heat treatment temperature, and heat treatment time may be adjusted in the heat treatment in a reducing atmosphere described later. In addition, when designing a glass that shields from the visible light range to the near infrared range, the OD may be set to be high at a wavelength in the near infrared range (for example, a wavelength of 1100 nm). To set the OD to be high at a wavelength in the near infrared range (for example, a wavelength of 1100 nm), for example, the Ag content may be adjusted, and the hydrogen concentration, heat treatment temperature, and heat treatment time may be adjusted in the heat treatment in a reducing atmosphere described later.

[0033] (Refractive Index) In the glass according to this embodiment, the refractive index nd is not particularly limited. In this embodiment, a glass having a refractive index nd according to the application can be used. For example, the refractive index nd can be 1.4 to 2.15, and preferably 1.5 to 1.85.

[0034] In the glass according to the present embodiment, a plurality of colored layers having small thicknesses can be provided at a predetermined interval on the opposing portions of both sides of the glass so that the portions on which the colored layers are not formed function as slits. In this case, by adjusting the refractive index of the glass, even if the angle of incidence of the light beam entering the slit portion is large (the light beam enters at a shallow angle), the light beam can be absorbed by the colored layer formed on the rear surface of the glass to prevent the light beam from passing through the adjacent slits, and the same effect as when the colored layer is provided over the entire thickness of the glass can be obtained, and the interval between the slits can be narrowed. Note that if the refractive index of the glass is too low, when the angle of incidence of the light beam entering the slit portion is large, the light beam may pass through the adjacent slits, and the same effect as when the colored layer is provided over the entire thickness of the glass may not be obtained.

[0035] (Abbe number) In the glass according to this embodiment, the Abbe number vd is not particularly limited. In this embodiment, a glass having an Abbe number vd according to the application can be used. For example, the Abbe number vd can be 15 to 95, and preferably 20 to 65.

[0036] (Glass composition) The composition of the glass according to this embodiment is not particularly limited, except that the colored layer contains Ag as a glass component. The colored layer is colored by adding Ag to the glass by the method described below. The glass composition is the same in the portion that can become the colored layer before Ag is added (the portion that becomes the colored layer after coloring) and the non-colored portion. That is, the Ag content is different between the colored layer and the non-colored portion. In addition, when Ag is added to the glass by ion exchange, the content of alkali metals such as Li, Na, and K may also be different between the colored layer and the non-colored portion.

[0037] The glass before the colored layer is formed preferably has a composition that allows easy introduction of Ag. In this embodiment, a preferred glass composition will be described based on cation %. Note that the glass before the colored layer is formed has the same composition as the glass of the non-colored portion in the glass having the colored layer.

[0038] In the preferred glass composition, Si 4+ The lower limit of the content of Si is preferably 10.0%, and may further be 13.0%, 15.0%, 18.0%, 20.0%, 25.0%, or 30.0%. 4+ The upper limit of the content of Si is preferably 90.0%, and may further be 80.0%, 70.0%, 65.0%, or 60.0%. 4+ By including this, it becomes easy to introduce Ag into the glass, and the glass can be colored efficiently.

[0039] Therefore, in the preferred glass composition, the network former Si 4+ , B 3+ , P 5+ Si content relative to the total content4+ The ratio of the content of [Si 4+ / (Si 4+ +B 3+ +P 5+ The lower limit of ) is preferably 0.30, and may further be 0.40, 0.50, 0.60, 0.70, 0.80, or 0.85.

[0040] The inclusion of alkali metal ions in the glass facilitates molten salt ion exchange. Therefore, in the preferred glass composition, Li + , Na + , K + The total content of Li + +Na + +K + The lower limit of the total content (Li) is preferably 5.0%, and may further be 10.0%, 15.0%, 20.0%, or 25.0%. + +Na + +K + The upper limit of the content of Ag in the alloy is preferably 50.0%, and more preferably 45.0%. By including these metal ions, Ag can be efficiently introduced by molten salt ion exchange.

[0041] Among the alkali metal ions, Li + , Na + The inclusion of Li facilitates molten salt ion exchange. Therefore, in a preferred glass composition, + , Na + The total content of Li + +Na + The lower limit of the total content (Li) is preferably 5.0%, and may further be 10.0%, 15.0%, 20.0%, or 25.0%. + +Na + The upper limit of the content of Ag in the alloy is preferably 50.0%, and more preferably 45.0%. By including these metal ions, Ag can be efficiently introduced by molten salt ion exchange.

[0042] In this embodiment, the glass may be chemically strengthened. When the glass is chemically strengthened, the glass preferably contains an alkali metal element as a glass component, and more preferably contains either or both of Li (lithium) and Na (sodium).

[0043] The chemical strengthening process may be performed simultaneously with the formation of the colored layer described later. The method of chemical strengthening is not particularly limited, but may be, for example, a method of contacting glass with a molten salt. It is preferable to perform chemical strengthening by a low-temperature ion exchange method in which ion exchange is performed in a temperature range not exceeding the glass transition temperature Tg. Chemical strengthening is a process in which a molten chemical strengthening salt is brought into contact with glass, and an alkali metal element having a relatively large atomic radius in the chemical strengthening salt is ion-exchanged with an alkali metal element having a relatively small atomic radius in the glass, so that the alkali metal element having a large atomic radius penetrates the surface layer of the glass, thereby generating compressive stress on the surface of the glass.

[0044] For example, when glass containing sodium (Na) as a glass component is immersed in a heated molten salt of potassium nitrate (KNO3), the sodium ions (Na + ) and potassium ion (K + ) undergoes ion exchange.

[0045] Potassium ion (K + ) is the size of a sodium ion (Na + ) is larger than the magnitude of the ion exchange. Therefore, a compressive stress layer is formed near the surface of the glass due to the ion exchange. As a result of the compressive stress layer being formed near the surface, the strength of the glass increases.

[0046] For example, in the case of glass containing lithium (Li) as a glass component, the glass can be immersed in a molten salt mixture of sodium nitrate (NaNO3) and potassium nitrate (KNO3). In this case, the lithium ions (Li + ) is about the same size as a lithium ion (Li +) is larger than the sodium ion (Na + ) and potassium ion (K + ) may be ion-exchanged.

[0047] Furthermore, when Ag is added to glass in the formation of a colored layer described later, if the glass is brought into contact with a molten salt of silver nitrate (AgNO3) or a molten salt of a mixed salt containing silver nitrate (AgNO3), lithium ions (Li + ) but its size is that of a lithium ion (Li + ) larger than silver ions (Ag + As a result, a compressive stress layer is formed near the surface of the glass, which can be chemically strengthened.

[0048] The glass according to this embodiment may contain one or more glass components selected from the group consisting of Sb ions, As ions, Sn ions, and Ce ions. The total content of Sb ions, As ions, Sn ions, and Ce ions may be, for example, 0 to 1.00 mol %. When the glass contains these ions, it is possible to prevent fine bubbles from remaining throughout the glass.

[0049] In this embodiment, the Sb ion is 3+ In addition, it includes all Sb ions with different valences. As ion means As 3+ , As 5+ In addition, it includes all As ions with different valences. Sn ions are Sn 4+ In addition, it includes all Sn ions with different valences. Ce ions are Ce 4+ In addition, it includes all Ce ions with different valences.

[0050] (Glass manufacturing) The glass according to the present embodiment is obtained by preparing a colorless glass and forming a colored layer thereon. The colorless glass may be produced according to a known glass production method. For example, a plurality of compounds are mixed and mixed thoroughly to form a batch raw material, the batch raw material is put into a melting vessel to form a molten glass, the molten glass is clarified and homogenized, then molded, and slowly cooled to obtain glass. Alternatively, the batch raw material is put into a melting vessel to perform rough melting. The molten material obtained by rough melting is quenched and crushed to produce cullet. Furthermore, the cullet is put into a melting vessel, heated and remelted (remelt) to form a molten glass, the molten glass is clarified and homogenized, then molded, and slowly cooled to obtain glass. A known method may be applied to the molding and slow cooling of the molten glass.

[0051] (Formation of colored layer) The colored layer can be formed by adding Ag to the portion of the glass obtained as described above where the colored layer is to be formed, and then heat treating the glass in a reducing atmosphere.

[0052] The method of adding Ag to the portion of the glass where a colored layer is to be formed is not particularly limited, but for example, a method of bringing the glass into contact with a molten salt is included. When bringing the glass into contact with the molten salt, it is preferable to adopt a low-temperature ion exchange method in which ion exchange is performed in a temperature range not exceeding the glass transition temperature Tg.

[0053] As a method for contacting glass with a molten salt, a method of immersing glass in a heated molten salt will be specifically exemplified below. The heated molten salt may contain a molten salt of silver nitrate (AgNO3) and further a molten salt of either or both of potassium nitrate (KNO3) and sodium nitrate (NaNO3). The concentration of silver nitrate (AgNO3) in the heated molten salt is preferably 0.01 to 100 mol%, more preferably 0.03 to 100 mol%, and further preferably 0.05 to 100 mol%. In addition, the concentration of potassium nitrate (KNO3) in the heated molten salt is preferably 0 to 99.99 mol%, and the concentration of sodium nitrate (NaNO3) is preferably 0 to 99.99 mol%.

[0054] As described above, when the colored layer is formed by contacting glass with a heated molten salt, it is preferable that the glass to be contacted with the molten salt contains an alkali metal. Ag contained in the molten salt is ion-exchanged with the alkali metal contained in the glass and is incorporated into the glass. Therefore, the content of the alkali metal in the glass before contacting with the molten salt is preferably 10 to 40 cation %. The alkali metal is Li + , Na + , and K + Examples include:

[0055] The temperature of the molten salt is not particularly limited, but is preferably a temperature not exceeding the glass transition temperature Tg. The time for which the glass is contacted with the molten salt is also not particularly limited, and can be appropriately adjusted depending on the desired degree of coloring, the range of the colored layer, the thickness of the colored layer, etc.

[0056] In addition to the above-mentioned method using a molten salt, other methods for adding Ag to the portion of the glass where a colored layer is to be formed include, for example, a method of applying a paste containing Ag to the glass, a method of contacting a thin film containing Ag with the glass, etc. When a paste or thin film containing Ag is used, heat treatment is performed as necessary to add Ag to the glass.

[0057] Next, the glass to which Ag has been added in the portion where a colored layer is to be formed as described above is heat-treated in a reducing atmosphere. The reducing atmosphere may contain a gas having reducing power. An example of the gas having reducing power is hydrogen. Therefore, it is preferable to use pure hydrogen gas or a hydrogen-containing gas as the reducing atmosphere, and a forming gas containing hydrogen may be used. The forming gas is a mixed gas consisting of hydrogen and nitrogen, and usually contains about 3 to 5 volume % of hydrogen.

[0058] The heat treatment is performed at a temperature 300° C. lower than the glass transition temperature (Tg-300) and lower than the softening point. The heat treatment time can be appropriately adjusted depending on the desired degree of coloring, the area of ​​the colored layer, the thickness of the colored layer, etc.

[0059] By heat treating the glass in a reducing atmosphere, the reduction reaction of the glass components proceeds preferentially in the portion of the glass in which Ag is present, and a colored layer is formed. According to this embodiment, by adjusting the method of adding Ag and the heat treatment conditions in the reducing atmosphere, a colored layer having a shape substantially the same as that of the portion of the glass to which Ag is added can be formed when observed from the glass surface. On the other hand, in the portion where Ag is not present, the reduction reaction does not proceed as easily as in the portion where Ag is present, so coloring is suppressed. As a result, the portion where Ag is not present can have sufficient transparency as a portion where no colored layer is formed (non-colored portion). Therefore, the difference in transmittance between the colored layer and the non-colored portion can be sufficiently ensured.

[0060] As described above, when a colored layer is formed by adding Ag to glass and heat-treating the glass in a reducing atmosphere, the colored layer is formed in a layered form from the glass surface toward the inside. For example, when a colored layer is formed on one side of a plate-like glass, a glass 10 consisting of a colored layer 11 and a non-colored portion 12 is obtained as shown in Fig. 1. When a colored layer is formed on both sides of a plate-like glass, a glass 10 having a non-colored portion 12 sandwiched between two colored layers 11 is obtained as shown in Fig. 2.

[0061] (Manufacturing of optical elements, etc.) The glass according to this embodiment can be used as an optical glass as it is. The optical element according to this embodiment can be obtained by preparing an uncolored optical element and forming a colored layer thereon. The uncolored optical element may be produced according to a known production method. For example, molten glass is poured into a mold and molded into a plate shape to produce a glass material. The obtained glass material is appropriately cut, ground, and polished to produce cut pieces of a size and shape suitable for press molding. The cut pieces are heated and softened, and press molded (reheat pressed) by a known method to produce an optical element blank that is similar to the shape of the optical element. The optical element blank is annealed, and then ground and polished by a known method to produce an optical element.

[0062] A colored layer can be formed on the produced optical element by the above-mentioned method. Alternatively, a colored layer may be formed during the production of the optical element.

[0063] The optically functional surface of the prepared optical element may be coated with an anti-reflection film, a total reflection film, or the like depending on the intended use.

[0064] (Application) According to one aspect of the present invention, an optical element containing the above glass can be provided. Examples of the type of optical element include lenses such as spherical lenses and aspherical lenses, and prisms. Examples of the shape of the lens include biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, concave meniscus lenses, and rod lenses. The optical element can be manufactured by a method including a process of processing a glass molded body formed from the above glass. Examples of the processing include cutting, machining, rough grinding, fine grinding, polishing, and the like.

[0065] As an example of an optical element, an optical element for blocking light obliquely incident on the light receiving surface of an image sensor such as a CCD or C-MOS sensor can be given. Conventionally, in order to block obliquely incident light on the light receiving surface of an image sensor, a method has been used in which black ink is applied to the portion of the cover glass surface of the image sensor where obliquely incident light is to be blocked, thereby providing light blocking properties. In this method, at the boundary between the portion where the black ink is applied and the portion where the black ink is not applied, light reflection occurs on the surface of the black ink, which causes stray light and reduces the image quality of the image sensor. In addition, when the temperature of the ink rises, it degasses, which causes the cover glass surface to become cloudy. In response to this, the glass of this embodiment is used, and a colored layer is provided at the portion where obliquely incident light is to be blocked, and the cover glass is used, thereby solving the problems of stray light and clouding due to degassing.

[0066] In addition, the glass according to this embodiment is not limited to a cover glass, and depending on the shape of the colored layer, it is also possible to have a function as a window for an optical sensor or the like. Examples of other optical elements include a blackened lens with a colored layer on the side of the lens, a glass encoder with a precisely shaped colored layer on the glass surface, and a screen with partial transparency. Here, the glass encoder is a disk-shaped glass plate that can be used in place of the rotary slit plate of an optical rotary encoder, and the part corresponding to the slit of the rotary slit plate can be a non-colored part, and the part corresponding to the shutter can be a colored layer. That is, the glass encoder has a region where the OD changes continuously and stepwise at the boundary between the non-colored part corresponding to the slit and the colored layer corresponding to the shutter. Therefore, even if the light incident on the glass encoder is diffracted and propagates to the boundary between the slit and the shutter, the light is attenuated at the boundary. As a result, the diffracted light is prevented from entering the optical sensor of the optical rotary encoder, and the malfunction of the encoder can be prevented. The above-mentioned effect obtained by attenuating light at the boundary between the colored layer and the non-colored portion can be obtained if the colored layer is present in a layer shape extending from the glass surface toward the inside.

[0067] In this embodiment, particularly when forming a glass encoder or a partially transparent screen, or when forming multiple lenses on a wafer, by adding Ag so that it is present in the desired locations of the glass, a colored layer can be formed all at once by heat treatment in a reducing atmosphere, and the desired locations can be made to have light-shielding properties.

[0068] The glass according to this embodiment can be used as an optical glass as it is, but the present invention is not limited to optical glass. According to one aspect of the present invention, since the colored layer can be formed at any position, a glass article including the above glass can be provided by utilizing the decorativeness of the colored layer. Examples of glass articles include, but are not limited to, daily necessities such as tableware and stationery, Buddhist altar implements, ornaments, jewelry, works of art, and exteriors of small electronic devices. The glass article according to this embodiment can have a desired figure, character, pattern, and design by the colored layer. Here, in the conventional case, that is, when a film is formed on the surface of an article and a pattern of a desired shape is applied, problems such as peeling of the film on the surface of the article and change in color of the film are likely to occur. On the other hand, in this embodiment, the colored layer exists in a layered form from the surface of the glass toward the inside. That is, the glass itself is colored. Therefore, the colored layer does not peel off, and the color of the colored layer is unlikely to change. That is, according to this embodiment, a glass article can be provided that does not cause problems such as peeling of the pattern or change in color. EXAMPLES

[0069] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0070] Glass samples having glass compositions I, II, III, and IV shown in Table 1 were prepared by the following procedure, and various evaluations were carried out.

[0071] [Table 1]

[0072] [Glass manufacturing] Oxides, hydroxides, carbonates, and nitrates corresponding to the components of glass were prepared as raw materials, and the raw materials were weighed and mixed so that the composition of the resulting glass would be each composition shown in Table 1, and the raw materials were thoroughly mixed. The resulting mixed raw materials (batch raw materials) were placed in a platinum crucible and heated at 1000 to 1550°C for 2 to 3 hours to obtain molten glass. The molten glass was stirred to homogenize it and clarify it, and then cast into a mold preheated to an appropriate temperature. The cast glass was heat treated for about 1 hour near the glass transition temperature Tg and allowed to cool to room temperature in a furnace. Glasses having compositions I, II, and IV were processed into plates with a thickness of 1.0 mm, and glass having composition III was processed into plates with a thickness of 3.0 mm, and both surfaces were precision-polished (optically polished) to obtain glass samples.

[0073] [Confirmation of glass composition] The content of each glass component in the obtained glass sample was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), and it was confirmed that each composition was as shown in Table 1.

[0074] [Optical property measurements] The refractive index nd, Abbe number vd, glass transition temperature Tg, and specific gravity of the obtained glass sample were measured. The results are shown in Table 1. The refractive index nd, Abbe number vd, glass transition temperature Tg, and specific gravity of the glass sample were all approximately the same as the values ​​after the colored layer was formed, and were within the range of values ​​indicated by significant figures in Table 1.

[0075] (i) Refractive index nd and Abbe number νd The refractive indices nd, ng, nF, and nC were measured according to the refractive index measurement method of JIS standard JIS B 7071-1, and the Abbe number vd was calculated according to formula (1). νd=(nd-1) / (nF-nC) (1)

[0076] (ii) Glass transition temperature Tg The glass transition temperature Tg was measured using a thermomechanical analyzer (TMA4000S) manufactured by MAC Sciences at a heating rate of 4° C. / min.

[0077] (iii) Specific gravity The specific gravity was measured by the Archimedes method.

[0078] (Example 1-1) [Formation of colored layer] A glass sample having composition I was immersed in the molten salt for 4 hours at 400° C. The concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) in the molten salt used in each example are as shown in Table 2. In Example 2-3, the colored layer was formed using silver paste.

[0079] [Table 2]

[0080] The glass sample immersed in the above molten salt was heat treated at 450° C. for 5 hours in a pure hydrogen atmosphere as a reducing atmosphere.

[0081] A colored layer was formed on the portion of the glass sample that had been in contact with the molten salt. That is, a glass sample was obtained that had a colored layer on the outer edge of the glass sample and a non-colored portion on the inner side thereof.

[0082] [Confirmation of Ag in the colored layer] The colored layer of the obtained glass sample was examined for the presence or absence of Ag from the surface of the colored layer using a scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX). As a result, it was confirmed that the colored layer of the obtained glass sample contained Ag.

[0083] [Ag content in colored layer] The obtained glass samples were analyzed by scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX) to examine the change in the Ag content in the thickness direction of the colored layer. The results are shown in Figure 5(2). In Figure 5(2), the right end of the graph is the surface of the glass sample, and moving left on the graph (i.e., moving in the direction of the arrow) increases the depth in the thickness direction of the glass sample. It was confirmed that the colored layer of the obtained glass sample contains Ag, and that the Ag content changes in the thickness direction of the colored layer. In addition, an SEM image of the cross section of the obtained glass sample is shown in Figure 5(3). In Figure 5(3), the glass sample appears white to gray. In Figure 5(3), the colored layer contains Ag and has a higher specific gravity than the non-colored part inside the glass, so it appears whiter.

[0084] In addition, the Ag concentration of the colored layer of the obtained samples was measured by the fundamental parameter method using a Rigaku X-ray fluorescence (XRF) analyzer (ZSX Primus). For glasses containing Li and B, the amounts of Li2O and B2O3 were considered as the amounts charged. The results are shown in Table 3.

[0085] [Transmittance measurement] The external transmittance was measured in the wavelength range of 300nm to 1500nm for the part of the glass sample with the colored layer. The external transmittance is defined as the percentage of the transmitted light intensity relative to the incident light intensity when light is incident in the thickness direction of the glass sample [transmitted light intensity / incident light intensity x 100]. The external transmittance also includes the reflection loss of light rays on the sample surface. The transmittance for the part with the colored layer is shown in Figure 3. Table 3 also lists the maximum transmittance in the visible light region.

[0086] [OD measurement] For the portion of the glass sample having a colored layer, the incident light intensity I0 and the transmitted light intensity I at wavelengths of 780 nm and 1100 nm were measured, and OD (optical density) was calculated using the following formula. The results are shown in Table 3. OD=-log 10 (I / I0)

[0087] (Example 1-2) A glass sample immersed in molten salt was heat-treated at 450°C for 5 hours while supplying forming gas (hydrogen 3% by volume, nitrogen 97% by volume) at a flow rate of 30 mL / min as a reducing atmosphere, and a colored layer was formed in the same manner as in Example 1-1 to obtain a glass sample having a colored layer and a non-colored portion. As in Example 1-1, the presence or absence of Ag in the colored layer was confirmed, and it was confirmed that Ag was contained in the colored layer of the obtained glass sample. In addition, the transmittance and OD were measured in the same manner as in Example 1-1. The transmittance of the portion having the colored layer is shown in Figure 4(1), and the transmittance of the non-colored portion is shown in Figure 4(2). Table 3 shows the OD, the maximum value of the transmittance in the visible light region, and the Ag concentration of the colored layer.

[0088] (Example 2-1) A glass sample having composition II was immersed in a molten salt with the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) shown in Table 2, and heat-treated in a pure hydrogen atmosphere as a reducing atmosphere at 470°C for 5 hours, but a colored layer was formed in the same manner as in Example 1-1 to obtain a glass sample having a colored layer and a non-colored portion. The transmittance and OD were measured in the same manner as in Example 1-1. The transmittance of the portion having the colored layer is shown in Figure 5(1). The OD, maximum value of transmittance in the visible light region, and Ag concentration of the colored layer are shown in Table 3.

[0089] (Example 2-2) A colored layer was formed in the same manner as in Example 2-1, except that a glass sample having composition II was immersed in a molten salt in which the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) were as shown in Table 2, and a glass sample having a colored layer and a non-colored portion was obtained. The Ag amount, transmittance, and OD of the colored layer were measured in the same manner as in Example 2-1. The transmittance of the portion having the colored layer is shown in FIG. 6(1). The OD, maximum value of transmittance in the visible light region, and Ag concentration of the colored layer are shown in Table 3. The change in the Ag amount in the thickness direction of the colored layer is shown in FIG. 6(2). It was confirmed that the colored layer of the obtained glass sample contained Ag, and that the Ag amount changed in the thickness direction of the colored layer. In addition, an SEM image of a cross section of the obtained glass sample is shown in FIG. 6(3).

[0090] (Example 2-3) A silver paste was applied to a portion of the surface of a glass sample having composition II, and the sample was heat-treated at 400°C for 12 hours under vacuum to introduce Ag into the sample. The glass sample was then heat-treated at 471°C for 5 hours in a pure hydrogen atmosphere as a reducing atmosphere to obtain a glass sample having a colored layer and a non-colored portion. As in Example 1-1, the presence or absence of Ag in the colored layer was confirmed, and it was confirmed that Ag was contained in the colored layer of the obtained glass sample. The transmittance of the portion having the colored layer is shown in Figure 7(1). The transmittance of the non-colored portion is shown in Figure 7(2). Table 3 shows the OD, maximum transmittance in the visible light region, and Ag concentration of the colored layer.

[0091] (Examples 2-4) A glass sample having composition II was immersed in a molten salt having the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) shown in Table 2 at 400°C for 4 hours to introduce Ag into the sample. The glass sample was then heat-treated in a pure hydrogen atmosphere as a reducing atmosphere at 471°C for 5 hours to obtain a glass sample having a colored layer and a non-colored portion. As in Example 1-1, the presence or absence of Ag in the colored layer was confirmed, and it was confirmed that Ag was contained in the colored layer of the obtained glass sample. The transmittance of the portion having the colored layer is shown in Figure 8(1). The transmittance of the non-colored portion is shown in Figure 8(2). Table 3 shows the OD, maximum transmittance in the visible light region, and Ag concentration of the colored layer.

[0092] (Example 3-1) A glass sample having composition III was immersed in a molten salt in which the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) were as shown in Table 2, and heat-treated in a pure hydrogen atmosphere as a reducing atmosphere at 500°C for 5 hours. A colored layer was formed in the same manner as in Example 1-1, and a glass sample having a colored layer and a non-colored portion was obtained. As in Example 1-1, the presence or absence of Ag in the colored layer was confirmed, and it was confirmed that Ag was contained in the colored layer of the obtained glass sample. In addition, the transmittance and OD were measured in the same manner as in Example 1-1. The transmittance of the portion having the colored layer is shown in Figure 9. The OD, the maximum value of the transmittance in the visible light region, and the Ag concentration of the colored layer are shown in Table 3.

[0093] (Example 3-2) A glass sample having composition III was immersed in a molten salt with the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) shown in Table 2, and a colored layer was formed in the same manner as in Example 3-1 to obtain a glass sample having a colored layer and a non-colored portion. The Ag amount, transmittance, and OD of the colored layer were measured in the same manner as in Example 2-1. The transmittance of the portion having the colored layer is shown in Figure 10(1). The OD, maximum value of transmittance in the visible light region, and Ag concentration of the colored layer are shown in Table 3. The change in the Ag amount in the thickness direction of the colored layer is shown in Figure 10(2). It was confirmed that the colored layer of the obtained glass sample contained Ag, and that the Ag amount changed in the thickness direction of the colored layer.

[0094] (Example 3-3) A colored layer was formed in the same manner as in Example 3-1, except that a glass sample having composition III was immersed in a molten salt in which the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) were as shown in Table 2, and a glass sample having a colored layer and a non-colored portion was obtained. The Ag amount and transmittance of the colored layer were measured in the same manner as in Example 2-1. The transmittance of the portion having the colored layer is shown in FIG. 11(1). The change in the Ag amount in the thickness direction of the colored layer is shown in FIG. 11(2). It was confirmed that the colored layer of the obtained glass sample contained Ag, and that the Ag amount changed in the thickness direction of the colored layer. In addition, an SEM image of a cross section of the obtained glass sample is shown in FIG. 11(3).

[0095] Example 4 A glass sample having composition IV was immersed in a molten salt having the concentrations of silver nitrate (AgNO3), potassium nitrate (KNO3), and sodium nitrate (NaNO3) shown in Table 2 at 400°C for 4 hours to introduce Ag into the sample. As in Example 1-1, the presence or absence of Ag in the colored layer was confirmed, and it was confirmed that Ag was contained in the colored layer of the obtained glass sample. The glass sample was then heat-treated at 591°C for 5 hours in a pure hydrogen atmosphere as a reducing atmosphere to obtain a glass sample having a colored layer and a non-colored portion. The transmittance of the portion having the colored layer is shown in Figure 12(1). The transmittance of the non-colored portion is shown in Figure 12(2). Table 3 shows the OD, maximum transmittance in the visible light region, and Ag concentration of the colored layer.

[0096] [Table 3]

Claims

1. Having a colored layer, The above colored layer contains Ag as a glass component, Glass in which the maximum transmittance of the above-mentioned colored layer in the visible light region is 20% or less.

2. The OD of the portion having the colored layer at a wavelength of 780 nm is 0.5 or more, and / or The glass according to claim 1, wherein the OD of the uncolored portion at a wavelength of 780 nm is 0.2 or less.

3. The OD of the portion having the colored layer at a wavelength of 1100 nm is 0.5 or more, and / or The glass according to claim 1, wherein the OD of the uncolored portion at a wavelength of 1100 nm is 0.2 or less.

4. The glass according to claim 1, having two opposing surfaces and having a colored layer on both surfaces.

5. The glass according to claim 1, wherein the glass composition is the same in the portion that may become a colored layer before the addition of Ag and in the uncolored portion.

6. Expressed in cation percentage, The Si 4+ content is 10.0% to 90.0%. The glass according to claim 1, wherein the total content of Li+, Na+, and K+ (Li+ + Na+ + K+) is 5.0 to 50.0%.

7. The glass according to claim 1, wherein the glass surface has a compressive stress layer in which compressive stress is applied.

8. Optical glass comprising the glass described in any one of claims 1 to 7.

9. An optical element comprising the glass described in any one of claims 1 to 7.

10. An image sensor comprising glass according to any one of claims 1 to 7, wherein the glass is equipped on the light-receiving surface to block obliquely incident light.

11. An optical sensor having a window containing glass as described in any one of claims 1 to 7.

Images