Transparent substrate with film and method for manufacturing the same, top plate for cooking appliance, window glass for heating appliance, and cover glass

Abstract

To provide a transparent substrate with a film whose color tone is less likely to change even when heated at high temperatures, such as a top plate for a cooker, and which is excellent in beauty during light-out of a light source.SOLUTION: A transparent substrate with a film 1 includes a transparent substrate 2 and a light absorption film 3 disposed on one main surface 2a of the transparent substrate 2. The light absorption film 3 contains Ag, Fe, and Cr.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a transparent substrate with a film, and a top plate for a cooker, a window glass for a heating cooker, and a cover glass using the transparent substrate with a film. 【Background Art】 【0002】 Conventionally, in cookers such as electromagnetic cookers, radiant heater cookers, and gas cookers, in order to conceal the internal structure of the cooker, a top plate made of black glass or transparent glass provided with a black coating film is used. In such cookers, in order to display various information such as power supply and heating status on the top plate, an LED (Light Emitting Diode), a liquid crystal display, or a liquid crystal display having a touch panel function may be used in combination. 【0003】 Patent Document 1 below discloses a top plate for a cooker including a glass plate, an inorganic pigment layer provided on the glass plate, and a display layer provided on the inorganic pigment layer. The inorganic pigment layer contains a pigment and glass. The display layer has a transmissive portion that transmits LED light or the like and a heat-resistant resin portion that blocks LED light or the like. In Patent Document 1, characters, numbers, symbols, etc. are displayed by changing the shape of the transmissive portion that transmits LED light or the like or by transmitting patterned light in the transmissive portion. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2014-215018 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 Incidentally, when using LEDs, liquid crystal displays, or liquid crystal displays with touch panel functionality in combination with a cooktop top plate, it is required that various information be clearly visible when the light source is on, and that the internal structure of the cooktop be concealed when the light source is off. However, when a black-colored glass substrate is used as the top plate, the internal structure of the cooktop can be concealed when the light source is off, but there is a problem that various information is difficult to see when the light source is on. 【0006】 In this regard, Patent Document 1 describes a method in which a black inorganic pigment layer is provided in the display area, thereby attempting to conceal the internal structure of the cooker. However, when a black inorganic pigment layer is provided, as in the top plate of Patent Document 1, it does not become achromatic black when the light source is turned off, which may impair the aesthetic appearance. 【0007】 Furthermore, since cooktop top plates are repeatedly heated and used, high heat resistance is required. However, when a black inorganic pigment layer is provided, as in the top plate described in Patent Document 1, the optical properties change due to heating, and the color may change. As a result, the desired black color may not be achieved when the light source is turned off, and the aesthetic appearance may be compromised. 【0008】 The object of the present invention is to provide a film-coated transparent substrate that does not easily change color even when heated at high temperatures, such as a top plate for a cooking appliance, and has excellent aesthetic appeal when the light source is turned off, as well as a top plate for a cooking appliance, a window glass for a cooking appliance, and a cover glass using the film-coated transparent substrate. [Means for solving the problem] 【0009】 The film-coated transparent substrate according to the present invention comprises a transparent substrate and a light-absorbing film provided on one main surface of the transparent substrate, wherein the light-absorbing film contains Ag, Fe, and Cr. 【0010】 In the present invention, it is preferable that the light-absorbing film further contains O. 【0011】 In the present invention, it is preferable that the mass ratio of Cr to Fe (Cr / Fe) is 0.10 or more and 0.60 or less. 【0012】 In the present invention, it is preferable that the light-absorbing film has a matrix containing Fe, Cr, and O, and that Ag is dispersed in the matrix. 【0013】 In the present invention, the average absorption coefficient of the light-absorbing film at wavelengths of 400 nm to 700 nm is 0.5 μm. -1 or more, 80μm -1 The following is preferable: 【0014】 In the present invention, when the absorption coefficient at a wavelength of 436 nm is α1, the absorption coefficient at a wavelength of 546 nm is α2, and the absorption coefficient at a wavelength of 700 nm is α3, it is preferable that α1 / α2 is 0.8 or more and 2.0 or less, and α3 / α2 is 0.8 or more and 2.0 or less. It is more preferable that α1 / α2 is 0.8 or more and 1.25 or less, and α3 / α2 is 0.8 or more and 1.25 or less. 【0015】 In the present invention, the absorption coefficient at wavelength λ in the light absorption film is α λ The average absorption coefficient in the wavelength range of 400 nm to 700 nm is defined as α AVE In this case, it is preferable that the absorbed mean deviation M, shown in the following formula (1), is 0.30 or less. 【0016】 【number】 【0017】 In the present invention, a dielectric multilayer film may be further provided on the light-absorbing film. 【0018】 In the present invention, a dielectric multilayer film is provided on the transparent substrate and includes the light-absorbing film. The dielectric multilayer film may be a laminate in which a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index are alternately laminated. In this case, at least one of the high refractive index films may be the light-absorbing film. Also, at least one of the low refractive index films may be the light-absorbing film. 【0019】 The cooking appliance top plate according to the present invention comprises a film-coated transparent substrate constructed according to the present invention, wherein the transparent substrate has a cooking surface on which cooking appliances are placed and a back surface opposite to the cooking surface, and the light-absorbing film is provided on the back surface of the transparent substrate. 【0020】 The window glass for a cooking appliance according to the present invention is a window glass used in a cooking appliance, comprising a transparent substrate with a film constructed according to the present invention, characterized in that the light-absorbing film is arranged on the main surface of the transparent substrate on the heating device side of the cooking appliance. 【0021】 The cover glass according to the present invention is a cover glass used in a display, comprising a transparent substrate with a film constructed according to the present invention, characterized in that the light-absorbing film is disposed on the main surface of the transparent substrate opposite to the side on which the display is provided. [Effects of the Invention] 【0022】 According to the present invention, it is possible to provide a film-coated transparent substrate that does not easily change color even when heated at high temperatures, such as a top plate for a cooking appliance, and has excellent aesthetic appeal when the light source is turned off, as well as a top plate for a cooking appliance, a window glass for a cooking appliance, and a cover glass using the film-coated transparent substrate. [Brief explanation of the drawing] 【0023】 [Figure 1] Figure 1 is a schematic cross-sectional view showing a film-coated transparent substrate according to a first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing a film-coated transparent substrate according to a second embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing a film-coated transparent substrate according to a third embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fourth embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fifth embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing a top plate for a cooking appliance according to one embodiment of the present invention. [Figure 7] Figure 7 is a schematic cross-sectional view showing a cover glass according to one embodiment of the present invention. [Figure 8] Figure 8 shows the transmission spectrum of the film-coated transparent substrate after heat treatment in Example 1. [Figure 9] Figure 9 shows the transmission spectrum of the film-coated transparent substrate after heat treatment of Comparative Example 1. [Figure 10] Figure 10 shows the relationship between the heat treatment temperature of the film-coated transparent substrate in Example 1 and the changes in a* and b* before and after heat treatment. [Figure 11] Figure 11 shows the relationship between the heat treatment temperature of the film-coated transparent substrate of Comparative Example 1 and the changes in a* and b* before and after heat treatment. [Figure 12] Figure 12 shows the relationship between the heat treatment temperature of the film-coated transparent substrate in Example 1 and the changes in x and y before and after the heat treatment. [Figure 13] Figure 13 shows the relationship between the heat treatment temperature of the film-coated transparent substrate of Comparative Example 1 and the changes in x and y before and after heat treatment. [Modes for carrying out the invention] 【0024】 Preferred embodiments are described below. However, the following embodiments are merely illustrative, and the present invention is not limited to these embodiments. In addition, in each drawing, components having substantially the same function may be referred to by the same reference numerals. 【0025】 [Transparent substrate with film] (First embodiment) Figure 1 is a schematic cross-sectional view showing a film-coated transparent substrate according to a first embodiment of the present invention. As shown in Figure 1, the film-coated transparent substrate 1 comprises a transparent substrate 2 and a light-absorbing film 3. The transparent substrate 2 has opposing first main surfaces 2a and second main surfaces 2b. The light-absorbing film 3 is provided on the first main surface 2a of the transparent substrate 2. 【0026】 In this embodiment, the transparent substrate 2 has a substantially rectangular plate shape. However, the transparent substrate 2 may also have a substantially circular plate shape, and its shape is not particularly limited. 【0027】 The transparent substrate 2 transmits light in the wavelength range of 400 nm to 700 nm. The transparent substrate 2 may be colored, but it is preferable to be colorless and transparent from the viewpoint of further enhancing its aesthetic appeal. In this specification, "transparent" means that the average light transmittance in the visible wavelength range of 400 nm to 700 nm is 80% or more. Furthermore, "colorless" means that the saturation of the transmitted light when irradiated with a D65 light source is 2 or less. 【0028】 In this embodiment, the transparent substrate 2 is made of glass. However, the transparent substrate 2 may be made of other materials such as ceramics, as long as it is a transparent substrate. 【0029】 The glass constituting the transparent substrate 2 is preferably made of glass with a high glass transition temperature and low expansion, or low expansion crystallized glass. The transparent substrate 2 may be made of borosilicate glass, alkali-free glass, aluminosilicate glass, etc. A specific example of low expansion crystallized glass is "N-0" manufactured by Nippon Electric Glass Co., Ltd., which is an LAS-based crystallized glass. In this case, the heat resistance of the transparent substrate 2 can be further increased, and the coefficient of thermal expansion can be further reduced. Therefore, it can be suitably used in applications such as cooktop plates (hereinafter also simply referred to as "top plates") that undergo repeated heating and cooling. 【0030】 The thickness of the transparent substrate 2 is not particularly limited. The thickness of the transparent substrate 2 can be set appropriately according to the light transmittance, etc. For example, the thickness of the transparent substrate 2 can be about 0.035 mm to 5 mm. 【0031】 The light-absorbing film 3 contains Ag, Fe, and Cr. In particular, in this embodiment, the light-absorbing film 3 further contains O (oxygen). Specifically, the light-absorbing film 3 is a film containing Ag, iron oxide, and chromium oxide. In addition, the light-absorbing film 3 may also contain nickel oxide, molybdenum oxide, copper oxide, etc. 【0032】 The method for forming the light-absorbing film 3 is not particularly limited, but for example, it can be formed by physical vapor deposition (PVD), such as sputtering, pulsed laser deposition (PLD), or evaporation. 【0033】 In sputtering and pulsed laser deposition (PLD), the light-absorbing film 3 can be deposited using, for example, a mixed target of Ag and stainless steel. Alternatively, the Ag target and the stainless steel target may be used separately. Stainless steel refers to an alloy steel with an Fe content of 50% by mass or more, a Cr content of 10.5% by mass or more, and a C content of 1.2% by mass or less. Examples of stainless steel that can be used include SUS304, SUS301, and SUS316. When using a stainless steel target, the magnetism is reduced compared to an Fe target, which stabilizes the discharge and allows for even more stable film deposition. In particular, when using an austenitic stainless steel target, the non-magnetic (paramagnetic) nature stabilizes the discharge and allows for particularly stable film deposition. 【0034】 For film deposition by sputtering, for example, the substrate temperature can be set to 15°C to 400°C, the flow rate of an inert gas such as argon gas used as the sputtering gas can be set to 10 sccm to 1000 sccm, the oxygen gas flow rate can be set to 0 sccm to 400 sccm, and the applied power can be set to 1 kW to 60 kW. 【0035】 The film-coated transparent substrate 1 of this embodiment has the above configuration, so that when the light source is lit, various information can be clearly displayed, and when the light is turned off, it can have excellent aesthetic appeal. In particular, when heated at high temperatures, such as in a cooktop top plate, the color does not easily change, and excellent aesthetic appeal can be stably maintained when the light source is turned off. This point can be explained as follows. 【0036】 Conventionally, when a black-colored glass substrate is used for the top plate of a cooking appliance, the internal structure of the appliance can be concealed when the light source, such as an LED or liquid crystal display, is turned off. However, when the light source is on, various information becomes difficult to see. On the other hand, when a black inorganic pigment layer is placed on a transparent substrate such as a glass substrate, the surface does not become achromatic black when the light source is turned off, which can impair the aesthetic appearance. 【0037】 Regarding this point, in the conventional top plate, the material constituting the inorganic pigment layer strongly absorbs the short wavelength side (violet and blue sides; high in light energy) of visible light and weakly absorbs the long wavelength side (red side; low in light energy), so the problem has been that it does not become achromatic black. 【0038】 On the other hand, in the light absorption film 3 of the present embodiment, the light absorption on the short wavelength side of visible light can be borne by the light absorption due to the band gap of iron oxide and chromium oxide, and the light absorption on the long wavelength side can be borne by the light absorption due to the free electrons of Ag. Therefore, the top plate becomes achromatic black even when the light is turned off, and it has excellent aesthetic properties. Also, the heat resistance can be enhanced while maintaining the light absorption on the short wavelength side of visible light. 【0039】 More specifically, the absorption coefficient α(λ) depending on the wavelength of light is represented by the following formula (I). 【0040】 α(λ)=α(λ) バンドギャップ型 +α(λ) 自由電子型 =A·λ -n +B·λ 2 ≒C·λ 0 …Formula (I) (In formula (I), A, B, and C are constants, and n>0.) 【0041】 That is, the absorption coefficient due to the band gap of iron oxide, chromium oxide, etc. that bears the light absorption on the short wavelength side of visible light is proportional to the nth power of the reciprocal of the wavelength, and the absorption coefficient due to the free electrons of Ag that bears the light absorption on the long wavelength side is proportional to the square of the wavelength. Therefore, the absorption coefficient α(λ) of the light absorption film 3 represented by the sum of these is generally independent of the wavelength and is likely to be a constant value at any wavelength. 【0042】 Thus, the transparent substrate 1 with the light-absorbing film 3 can uniformly absorb light, especially across almost the entire visible light spectrum. Furthermore, its heat resistance is enhanced, making it less susceptible to changes in optical properties due to heating, and thus less prone to color changes. Therefore, the transparent substrate 1 with the film can be achromatic black when the light source is turned off, providing stable and excellent aesthetics. Consequently, the transparent substrate 1 with the film can be suitably used in applications such as cooktop top plates and display cover glass. 【0043】 In the present invention, the Ag content in the light-absorbing film 3 is preferably 17% by mass or more, more preferably 30% by mass or more, preferably 65% ​​by mass or less, and more preferably 55% by mass or less. In this case, light can be absorbed more uniformly over almost the entire visible light spectrum. Note that the Ag content in the light-absorbing film 3 is the Ag content relative to the total metal element content in the light-absorbing film 3 excluding oxygen. 【0044】 In the present invention, regarding the content of metal elements excluding oxygen in the light-absorbing film 3, the Fe content in the light-absorbing film 3 is preferably 25% by mass or more, more preferably 32% by mass or more, preferably 60% by mass or less, and more preferably 50% by mass or less. The Cr content in the light-absorbing film 3 is preferably 4% by mass or more, more preferably 8% by mass or more, preferably 17% by mass or less, and more preferably 12% by mass or less. Note that the above Fe and Cr content in the light-absorbing film 3 are the respective content of Fe and Cr relative to the total content of metal elements excluding oxygen in the light-absorbing film 3. 【0045】 The light-absorbing film 3 may also contain Ni, Mo, Cu, S, Mn, P, Si, and C, which are components found in stainless steel. If the light-absorbing film 3 contains Ni, its content is preferably 3% by mass or more, more preferably 6% by mass or more, preferably 15% by mass or less, and more preferably 12% by mass or less. The above Ni content in the light-absorbing film 3 is the Ni content relative to the total metal element content in the light-absorbing film 3 excluding oxygen. Furthermore, the C content in the light-absorbing film 3 (overall) is preferably 1.2% by mass or less. 【0046】 In the light-absorbing film 3, the mass ratio of Cr to Fe (Cr / Fe) is preferably 0.10 or higher, more preferably 0.20 or higher, more preferably 0.60 or lower, and more preferably 0.40 or lower. In this case, changes in the color of the light-absorbing film 3 due to heating can be made even less likely. 【0047】 The light-absorbing film 3 may further contain Al. In this case, the color change of the light-absorbing film 3 due to heating can be made even less likely. The Al content in the light-absorbing film 3 is preferably 2.5% by mass or more, more preferably 5% by mass or more, preferably 35% by mass or less, and more preferably 30% by mass or less. However, when considering the absorption coefficient of the film, the light-absorbing film 3 does not need to contain substantially any Al. Substantially Al-free means that the Al content in the light-absorbing film 3 is 0% by mass or more and 0.3% by mass or less. The above Al content in the light-absorbing film 3 is the Al content relative to the total metal element content in the light-absorbing film 3 excluding oxygen. 【0048】 Furthermore, if the light-absorbing film 3 also contains Al, it can be formed using a mixed target of Ag, stainless steel, and Al. Alternatively, the Ag target, stainless steel target, and Al target may be used separately. 【0049】 The content of Ag, Fe, Ni, Cr, and Al in the light-absorbing film 3 can be measured by, for example, electron beam microanalyzer (EPMA), energy-dispersive X-ray spectrometry, wavelength-dispersive X-ray spectrometry, or inductively coupled plasma mass spectrometry, with measurement by electron beam microanalyzer (EPMA) being preferable. 【0050】 The thickness of the light-absorbing film 3 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, particularly preferably 20 nm or more, preferably 2 μm or less, more preferably 1 μm or less, even more preferably 500 nm or less, and particularly preferably 100 nm or less. When the thickness of the light-absorbing film 3 is within the above range, the display of various information can be made more clearly visible when the light source is lit, and the aesthetic appearance can be made even more superior when the light is turned off. 【0051】 In the present invention, it is preferable that the light-absorbing film 3 has a matrix containing Fe, Cr, and O, and that Ag is dispersed in the matrix. In particular, it is preferable that iron oxide and chromium oxide constitute the matrix in the light-absorbing film 3, and that Ag is dispersed in the matrix. In this case, the insulating properties of the light-absorbing film 3 can be further enhanced. Therefore, in this case, the film-coated transparent substrate 1 can be suitably used in a display with touch panel functionality or in a top plate for a cooking appliance that incorporates a display with touch panel functionality. Note that, as long as insulating properties are maintained, a portion of Ag may be present as a matrix component. 【0052】 The average absorption coefficient of the light-absorbing film 3 at wavelengths of 400 nm to 700 nm is preferably 0.5 μm. -1 Above, a comfortable 10μm -1 Preferably 80 μm -1 More preferably, 70 μm -1The following applies: If the average absorption coefficient is greater than or equal to the lower limit, for example, when the film-coated transparent substrate 1 is used as a top plate for a cooker, the internal structure of the cooker can be more reliably concealed. On the other hand, if the average absorption coefficient is less than or equal to the upper limit, when the light source is turned on, the display of various information can be made more reliably and clearly visible. The absorption coefficient of the light-absorbing film 3 can be derived from measurements of transmittance and reflectance using spectroscopic ellipsometry or a spectrophotometer. In this case, the measurement should be taken from the light-absorbing film 3 side while it is laminated on the transparent substrate 2. 【0053】 Furthermore, in the light-absorbing film 3, when the absorption coefficient at a wavelength of 436 nm is α1, the absorption coefficient at a wavelength of 546 nm is α2, and the absorption coefficient at a wavelength of 700 nm is α3, it is preferable that α1 / α2 is 0.8 or more and 2.0 or less, and α3 / α2 is 0.8 or more and 2.0 or less. It is even more preferable that α1 / α2 is 0.8 or more and 1.25 or less, and α3 / α2 is 0.8 or more and 1.25 or less. In this case, a more achromatic black color can be achieved when the light source is turned off, resulting in even greater aesthetic appeal. 【0054】 Furthermore, in the light-absorbing film 3, the absorption coefficient at wavelength λ is α λ The average absorption coefficient in the wavelength range of 400 nm to 700 nm is defined as α AVE In this case, it is preferable that the average absorption deviation M shown in the following formula (1) is 0.30 or less. In this case, when the light source is turned off, a more achromatic black can be achieved, resulting in even greater aesthetic appeal. 【0055】 【number】 【0056】 Furthermore, if the Ag content in the light-absorbing film 3 is low, the α1 / α2 ratio may become too large, the α3 / α2 ratio may become too small, and the average absorption deviation M may become too large. On the other hand, if the Ag content in the light-absorbing film 3 is high, the sheet resistance may decrease. Also, the α1 / α2 ratio may become too small, the α3 / α2 ratio may become too large, and the average absorption deviation M may become too large. 【0057】 The electrical resistance (sheet resistance) of the light-absorbing film 3 is preferably 10 5 Ω(10 5 Ω / □) or more, more preferably 10 6 Ω(10 6 Ω / □) or more, more preferably 10 7 Ω(10 7 The resistance is greater than or equal to Ω / □. In this case, since the light-absorbing film 3 is insulating, when used as a cover glass for an image display device or a top plate for a cooking appliance, even if a touch panel is added, the change in capacitance due to finger contact necessary for a capacitive touch sensor is maintained, and the touch panel can function. The sheet resistance can be measured using methods specified in ASTM D257, JIS K6271-1 (2015), JIS K6271-2 (2015), K6911 (1995), etc. 【0058】 In this invention, when a film-coated transparent substrate 1 is heat-treated at 500°C for 1 hour, the L of the transmitted light before and after heat treatment is measured. * a * b * a in color system * and b * The absolute values ​​of the changes in each are preferably 4 or less, and more preferably 2 or less. In this case, it is possible to further reduce the likelihood of changes in the color of the light-absorbing film 3 due to heating. 【0059】 L of the transparent substrate 1 with film * a * b * L in color systems * For example, 30 or more, 60 or less, a *For example, -5 or greater, 5 or less, b * For example, it can be -5 or greater and 5 or less. * This is the "brightness index" (L axis = 0 to 100), a * and b * This refers to the "Chromatic Neck exponent" (a-axis = -60 to +60, b-axis = -60 to +60). Also, L * a * b * The value can be measured from the light absorption film 3 side of the film-coated transparent substrate 1 using a spectrophotometer. For example, a spectrophotometer manufactured by Hitachi High-Tech Science Corporation, model number "U-4100", can be used. 【0060】 In the present invention, when the film-coated transparent substrate 1 is heat-treated at 500°C for 1 hour, it is preferable that the absolute values ​​of the changes in x and y in the transmitted light in the xyY color system before and after the heat treatment are 0.010 or less, and more preferably 0.005 or less. In this case, it is possible to further reduce the likelihood of changes in the color of the light-absorbing film 3 due to heating. 【0061】 In the xyY color system of the film-coated transparent substrate 1, x can be, for example, 0.25 or more and 0.35 or less, y can be, for example, 0.25 or more and 0.35 or less, and Y can be, for example, 10 or more and 50 or less. The xyY values ​​can be measured from the light absorption film 3 side of the film-coated transparent substrate 1 using a spectrophotometer. As a spectrophotometer, for example, Hitachi High-Tech Science Corporation, model number "U-4100" can be used. 【0062】 Saturation C of transmitted light from the film-coated transparent substrate 1 * T The chrominance C of the reflected light of the film-coated transparent substrate 1 is preferably 7 or less, more preferably 2 or less, even more preferably 1 or less, particularly preferably 0.8 or less, and most preferably 0.5 or less. * R The saturation C is preferably 7 or less, more preferably 2 or less, even more preferably 1 or less, particularly preferably 0.7 or less, and most preferably 0.5 or less. *This is L, which is adopted in JIS Z 8781-4:2013. * a * b * In the color system, the saturation C when illuminated by a D65 light source. * That is the case. Also, saturation C * chromaticity a * and b * More demanded, C * =((a * ) 2 +(b * ) 2 ) 1 / 2 It is represented by saturation C * If the value is below the above upper limit, the color can be made more achromatic black when the light source is turned off, resulting in an even more aesthetically pleasing appearance. 【0063】 Furthermore, from the perspective of making the boundary between display area A and non-display area B, which will be described later, even less visible, the brightness (L) of the reflected light between display area A and non-display area B is increased. * The absolute value of the difference between (C) is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less. Also, the saturation of the reflected light between display area A and non-display area B is (C) * R The absolute value of the difference between (L) is preferably 0.7 or less, more preferably 0.4 or less, and particularly preferably 0.3 or less. * The light absorption film 3 on the transparent substrate 1 with the film attached can be measured, for example, using a spectrophotometer (Olympus Corporation, model number "USPM-RU-II"). 【0064】 (Second to fifth embodiments) Figure 2 is a schematic cross-sectional view showing a film-coated transparent substrate according to a second embodiment of the present invention. As shown in Figure 2, in the film-coated transparent substrate 21, a dielectric multilayer film 26 is further provided on top of the light-absorbing film 3. Other aspects are the same as in the first embodiment. 【0065】 The dielectric multilayer film 26 is a laminated film in which a low refractive index film 27 with a relatively low refractive index and a high refractive index film 28 with a relatively high refractive index are alternately stacked in this order. In this embodiment, the dielectric multilayer film 26 has 5 layers. 【0066】 Examples of materials for the low refractive index film 27 include silicon oxide or aluminum oxide. 【0067】 Examples of materials for the high refractive index film 28 include niobium oxide, titanium oxide, zirconium oxide, hafnium oxide, tantalum oxide, tin oxide, silicon nitride, aluminum oxide, and aluminum nitride. 【0068】 Figure 3 is a schematic cross-sectional view showing a film-coated transparent substrate according to a third embodiment of the present invention. As shown in Figure 3, in the film-coated transparent substrate 31, a dielectric multilayer film 36 including a light-absorbing film 3 is provided on the first main surface 2a of the transparent substrate 2. Other aspects are the same as in the first embodiment. 【0069】 In the dielectric multilayer film 36, a low refractive index film 27 with a relatively low refractive index and a light-absorbing film 3 with a relatively high refractive index are alternately stacked in this order. In this embodiment, the dielectric multilayer film 36 has 5 layers. The light-absorbing film 3 is the light-absorbing film 3 described in the first embodiment, and the low refractive index film 27 is the low refractive index film 27 described in the second embodiment. One of the two light-absorbing films 3 may be the high refractive index film 28 described in the second embodiment. 【0070】 Figure 4 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fourth embodiment of the present invention. As shown in Figure 4, in the film-coated transparent substrate 41, a dielectric multilayer film 46 including a light-absorbing film 3 is provided on the first main surface 2a of the transparent substrate 2. Other aspects are the same as in the first embodiment. 【0071】 In the dielectric multilayer film 46, a high refractive index film 28 with a relatively high refractive index and a light-absorbing film 3 with a relatively low refractive index are alternately stacked in this order. Furthermore, the outermost layer is provided with a low refractive index film 27, as described in the second embodiment. When the low refractive index film 27 is provided as the outermost layer, the reflectivity can be further reduced and the chemical durability can be further improved. 【0072】 Furthermore, in this embodiment, the dielectric multilayer film 46 has 6 layers. The light absorption film 3 is the light absorption film 3 described in the first embodiment, and the low refractive index film 27 and high refractive index film 28 are the low refractive index film 27 and high refractive index film 28 described in the second embodiment. One of the two light absorption films 3 may be the low refractive index film 27 described in the second embodiment. 【0073】 Figure 5 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fifth embodiment of the present invention. As shown in Figure 5, in the film-coated transparent substrate 51, two layers of light-absorbing films 3 are provided on the transparent substrate 2. In addition, dielectric multilayer films 56A and 56B are provided between the transparent substrate 2 and the light-absorbing films 3, and between the two light-absorbing films 3, 3. The dielectric multilayer films 56A and 56B are composed of a low refractive index film 27 and a high refractive index film 28, respectively. Furthermore, the outermost layer is provided with the low refractive index film 27 described in the second embodiment. Other aspects are the same as in the second embodiment. 【0074】 In the second to fifth embodiments, the light-absorbing film 3 also contains Ag, Fe, and Cr. Therefore, with each film-coated transparent substrate, various information can be clearly displayed when the light source is lit, and the aesthetic appearance can be excellent when the light is turned off. In particular, the color does not easily change even when heated, and the aesthetic appearance can be stably excellent when the light source is turned off. 【0075】 Furthermore, when a dielectric multilayer film is provided, as in the second to fifth embodiments, an anti-reflective function can be added, for example. In this case, the contrast of the display can also be improved. 【0076】 In this case, as in the third embodiment, the light-absorbing film 3 may be used as a high-refractive-index film, or as in the fourth embodiment, the light-absorbing film 3 may be used as a low-refractive-index film. The light-absorbing film 3 can be used as either a low-refractive-index film or a high-refractive-index film by adjusting the magnitude of the refractive index by adjusting the deposition conditions such as the mass ratio of Ag to iron oxide and the partial pressure of oxygen. The refractive index of the light-absorbing film 3 can be adjusted, for example, within the range of 1.2 or more and 2.0 or less. 【0077】 [Cooking utensil top plate] Figure 6 is a schematic cross-sectional view showing a top plate for a cooking appliance according to one embodiment of the present invention. As shown in Figure 6, the top plate 61 for the cooking appliance comprises a film-coated transparent substrate 1. 【0078】 In the cooktop top plate 61, the second main surface 2b of the transparent substrate 2 constituting the film-coated transparent substrate 1 is the cooking surface. On the other hand, the first main surface 2a of the transparent substrate 2 constituting the film-coated transparent substrate 1 is the back surface. The cooking surface is the surface on which cookware such as pots and pans are placed. The back surface is the surface on the inside of the cooktop that faces the light source 62 such as an LED or display and the heating device. Therefore, the cooking surface and the back surface are in a front-back relationship. In this embodiment, the transparent substrate 2 is made of low-expansion crystallized glass. 【0079】 A light-absorbing film 3 is provided on the back surface (first main surface 2a) of the transparent substrate 2. A heat-resistant resin layer 63 is provided on the light-absorbing film 3. The heat-resistant resin layer 63 may be provided between the transparent substrate 2 and the light-absorbing film 3. In this embodiment, in a plan view, the area where the heat-resistant resin layer 63 is not provided is defined as the display area A. In a plan view, the area where the heat-resistant resin layer 63 is provided is defined as the non-display area B. 【0080】 The heat-resistant resin layer 63 is a light-shielding layer. Therefore, by providing the heat-resistant resin layer 63, the concealment of the internal structure of the cooker can be further and reliably enhanced. The heat-resistant resin layer 63 can be composed of a heat-resistant resin such as silicone resin and a coloring pigment, etc. Note that the heat-resistant resin layer 63 is not required. 【0081】 Below the film-coated transparent substrate 1, a light source 62, such as a display or LED, is provided. The light source 62 is a component provided for displaying information in the display area A. The information to be displayed in the display area A is not particularly limited and may include, for example, information indicating the status of the cooking appliance, such as whether the power is on or heating, or information such as the time. 【0082】 Light from the light source 62 passes through the light-absorbing film 3 and the transparent substrate 2 in display area A and is emitted to the outside. In addition, light from the light source 62 is blocked by the heat-resistant resin layer 63 in non-display area B. Therefore, by transmitting light from the light source 62 in display area A, characters, numbers, symbols, etc. can be displayed. 【0083】 The cooktop top plate 61 is equipped with a film-coated transparent substrate 1. Therefore, when the light source 62 is lit, various information can be clearly displayed, and when it is turned off, it can be aesthetically pleasing. In addition, the internal structure of the cooktop can be concealed, while the boundary between the display area A and the non-display area B can be made less visible. Furthermore, the color does not easily change even when the cooktop top plate 61 is heated to high temperatures during use. A display with touch panel functionality may be built into the inside of the cooktop. 【0084】 [Window glass for cooking appliances] Furthermore, the above-described top plate 61 for cooking appliances may be used as a window glass for cooking appliances such as microwave ovens and ovens. In that case, the second main surface 2b of the transparent substrate 2 constituting the above-described film-coated transparent substrate 1 can be made the main surface opposite to the heating device side in the cooking appliance, and the first main surface 2a of the transparent substrate 2 constituting the film-coated transparent substrate 1 can be made the main surface on the heating device side in the cooking appliance. 【0085】 [Cover glass] Figure 7 is a schematic cross-sectional view showing a cover glass according to one embodiment of the present invention. As shown in Figure 7, the cover glass 71 comprises a film-coated transparent substrate 1. The cover glass 71 is, for example, a cover glass used by being placed in front of a display. 【0086】 In the cover glass 71, the first main surface 2a of the transparent substrate 2 constituting the film-covered transparent substrate 1 is the main surface that is positioned on the outside. On the other hand, the second main surface 2b of the transparent substrate 2 constituting the film-covered transparent substrate 1 is the main surface on the display side. Therefore, in the cover glass 71, the light-absorbing film 3 is provided on the main surface 2a of the transparent substrate 2 opposite to the side on which the display is provided. 【0087】 The cover glass 71 also has a film-coated transparent substrate 1, so even when heated at high temperatures (for example, 300°C to 400°C) like a cooktop top plate, the color does not easily change, and it has excellent aesthetic appeal when the light source is turned off. 【0088】 The present invention will be described in further detail below based on examples. However, the following examples are merely illustrative. The present invention is not limited in any way to the following examples. 【0089】 (Example 1) In Example 1, a light-absorbing film was deposited on a transparent glass substrate by sputtering using a mixed target of Ag and stainless steel (SUS304). The Ag content in the mixed target was 32.6 mass%, and the stainless steel content was 67.4 mass%. The substrate temperature was 250°C, and the oxygen partial pressure was 0.03 Pa. In the light-absorbing film, excluding oxygen, the metallic element content was 48.022 mass% for Ag, 32.782 mass% for Fe, and 10.615 mass% for Cr. The mass ratio of Cr to Fe (Cr / Fe) was 0.32. The Ni content was 8.581 mass%. Each composition was measured using an electron beam microanalyzer (EPMA, JEOL Ltd., model number "JXA-8100"). Furthermore, the optical properties of the obtained light-absorbing film were n (refractive index) = 1.56 and k (extinction coefficient) = 1.2 (wavelength 550 nm). It was confirmed that iron oxide, chromium oxide, and nickel oxide constituted the matrix of the obtained light-absorbing film, and that Ag was dispersed within this matrix. Additionally, the obtained light-absorbing film was achromatic black in color. 【0090】 (Comparative Example 1) In Comparative Example 1, a light-absorbing film was deposited on a transparent glass substrate by sputtering using a mixed target of Ag and FeO. The Ag content in the mixed target was 32.6 mass%, and the Fe content was 67.4 mass%. The substrate temperature was 250°C, and the oxygen partial pressure was 0.025 Pa. In the light-absorbing film, the metal element content excluding oxygen was 58.1 mass% for Ag and 41.9 mass% for Fe. The composition of each element was measured using an electron beam microanalyzer (EPMA, JEOL Ltd., model number "JXA-8100"). The optical properties of the obtained light-absorbing film were n (refractive index) = 1.24 and k (extinction coefficient) = 1.4 (wavelength 550 nm). 【0091】 [evaluation] (Optical properties) In the light-absorbing film obtained in Example 1, when the absorption coefficient at a wavelength of 436 nm is α1, the absorption coefficient at a wavelength of 546 nm is α2, and the absorption coefficient at a wavelength of 700 nm is α3, then α1 / α2, α3 / α2, and the average absorption coefficient α AVE The absorbed mean deviation M was calculated. The results are shown in Table 1 below. 【0092】 [Table 1] 【0093】 (Heat resistance test) The film-coated transparent substrates obtained in Example 1 and Comparative Example 1 were heat-treated at temperatures of 200°C, 300°C, 400°C, and 500°C for 1 hour each. The transmission spectra and L2 were obtained for the film-coated transparent substrates prepared at each heat treatment temperature. * a * b * a in color system * and b * The x and y values ​​in the xyY color system, as well as the sheet resistance, were measured. 【0094】 Note that the transmission spectrum and the L of the transmitted light * a * b * a in color system * and b * Furthermore, x and y in the xyY color system were measured using a spectrophotometer (Hitachi High-Tech Science Co., Ltd., model number "U-4100"). Sheet resistance was measured using a DC two-terminal method with platinum electrodes. 【0095】 Figure 8 shows the transmission spectrum of the film-coated transparent substrate after heat treatment in Example 1. Figure 9 shows the transmission spectrum of the film-coated transparent substrate after heat treatment in Comparative Example 1. In addition, Figures 8 and 9 also show the transmission spectrum of the unheat-treated film-coated transparent substrate. 【0096】 Figure 8 shows that in the film-coated transparent substrate of Example 1, the waveform of the transmission spectrum remains almost unchanged regardless of the heat treatment temperature. Furthermore, the transmittance is almost constant in the wavelength range of 400 nm to 700 nm. On the other hand, Figure 9 shows that in the film-coated transparent substrate of Comparative Example 1, the waveform of the transmission spectrum changes significantly after heat treatment. 【0097】 Figure 10 shows the heat treatment temperature of the film-coated transparent substrate in Example 1, and the a before and after heat treatment. * and b * This figure shows the relationship with the amount of change of . Also, Figure 11 shows the heat treatment temperature of the film-coated transparent substrate of Comparative Example 1 and a before and after heat treatment. * and b * This figure shows the relationship with the amount of change. 【0098】 From Figure 10, in the film-coated transparent substrate of Example 1, a before and after heat treatment * and b * The change in L was less than 4 even at 500°C, indicating that the color hardly changed. On the other hand, as shown in Figure 11, the film-coated transparent substrate of Comparative Example 1 showed L before and after heat treatment. * a * b * a in color system * and b * The amount of change was greater than 4 at 500°C, resulting in a significant change in color. 【0099】 Figure 12 shows the relationship between the heat treatment temperature of the film-coated transparent substrate in Example 1 and the changes in x and y before and after heat treatment. Figure 13 shows the relationship between the heat treatment temperature of the film-coated transparent substrate in Comparative Example 1 and the changes in x and y before and after heat treatment. 【0100】 As shown in Figure 12, in the film-coated transparent substrate of Example 1, the change in x and y before and after heat treatment was 0.01 or less even at 500°C, indicating that the color hardly changed. On the other hand, as shown in Figure 13, in the film-coated transparent substrate of Comparative Example 1, the change in x and y before and after heat treatment was greater than 0.01 at 500°C, indicating that the color changed significantly. 【0101】 These results confirm that the transparent substrate with the film in Example 1 is less prone to color change due to heating and maintains excellent aesthetic appeal even when the light source is turned off. 【0102】 The measurement results of the sheet resistance (resistance value) of the film-coated transparent substrate of Example 1 at each heat treatment temperature are shown in Table 2 below. 【0103】 [Table 2] 【0104】 Table 2 shows that the film-coated transparent substrate of Example 1 exhibited high insulating properties regardless of the heat treatment temperature. [Explanation of Symbols] 【0105】 1, 21, 31, 41, 51… Transparent substrates with film 2…Transparent substrate 2a...First main surface 2b...Second main surface 3… Light-absorbing film 26, 36, 46, 56A, 56B… Dielectric multilayer film 27... Low refractive index film 28…High refractive index film 61… Cooking appliance top plate 62…Light source 63...Heat-resistant resin layer 71… Cover glass

Claims

[Claim 1] Transparent substrate and A light-absorbing film is provided on one main surface of the transparent substrate, Equipped with, The light-absorbing film contains Fe, Cr, Ni, and O, and comprises a matrix composed of iron oxide, chromium oxide, and nickel oxide, and Ag dispersed in the matrix. A transparent substrate with a film, wherein the Ni content relative to the total metal element content excluding oxygen in the light-absorbing film is 3% by mass or more. [Claim 2] The film-coated transparent substrate according to claim 1, wherein the mass ratio of Cr to Fe (Cr / Fe) is 0.10 or more and 0.60 or less. [Claim 3] The average absorption coefficient of the aforementioned light-absorbing film at wavelengths of 400 nm to 700 nm is 0.5 μm. －１ Above, 80μm －１ The transparent substrate with a film according to claim 1 or 2, which is as follows: [Claim 4] A transparent substrate with a film according to any one of claims 1 to 3, wherein, in the light-absorbing film, when the absorption coefficient at a wavelength of 436 nm is α1, the absorption coefficient at a wavelength of 546 nm is α2, and the absorption coefficient at a wavelength of 700 nm is α3, α1 / α2 is 0.8 or more and 2.0 or less, and α3 / α2 is 0.8 or more and 2.0 or less. [Claim 5] The transparent substrate with a film according to claim 4, wherein in the light-absorbing film, the ratio of α1 / α2 is 0.8 or more and 1.25 or less, and the ratio of α3 / α2 is 0.8 or more and 1.25 or less. [Claim 6] In the aforementioned light-absorbing film, the absorption coefficient at wavelength λ is α λ The average absorption coefficient in the wavelength range of 400 nm to 700 nm is defined as α ＡＶＥ A film-coated transparent substrate according to any one of claims 1 to 5, wherein the average absorption deviation M shown in the following formula (1) is 0.30 or less. [Math 1] [Claim 7] A transparent substrate with a film according to any one of claims 1 to 6, wherein a dielectric multilayer film is further provided on the light-absorbing film. [Claim 8] A film-coated transparent substrate according to any one of claims 1 to 6, comprising a dielectric multilayer film provided on the transparent substrate and including the light-absorbing film. [Claim 9] The dielectric multilayer film is a laminated film in which a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index are alternately stacked. The transparent substrate with a film according to claim 8, wherein at least one layer of the high refractive index film is the light-absorbing film. [Claim 10] The dielectric multilayer film is a laminated film in which a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index are alternately stacked. The transparent substrate with a film according to claim 8, wherein at least one of the low refractive index films is the light-absorbing film. [Claim 11] A transparent substrate with a film according to any one of claims 1 to 10, The transparent substrate has a cooking surface on which cooking utensils are placed and a back surface opposite to the cooking surface, A top plate for a cooking appliance, wherein the light-absorbing film is disposed on the back surface of the transparent substrate. [Claim 12] Window glass used in heating appliances, A transparent substrate with a film according to any one of claims 1 to 10, A window glass for a cooking appliance, wherein the light-absorbing film is disposed on the main surface of the transparent substrate on the heating device side of the cooking appliance. [Claim 13] A cover glass used in displays, A transparent substrate with a film according to any one of claims 1 to 10, A cover glass in which the light-absorbing film is disposed on the main surface of the transparent substrate opposite to the side on which the display is provided. [Claim 14] A method for manufacturing a film-coated transparent substrate according to any one of claims 1 to 10, A method for manufacturing a transparent substrate with a film, comprising forming the light-absorbing film on one main surface of the transparent substrate by sputtering using a mixed target of Ag and stainless steel. [Claim 15] A method for manufacturing a film-coated transparent substrate according to any one of claims 1 to 10, A method for manufacturing a transparent substrate with a film, comprising forming the light-absorbing film on one main surface of the transparent substrate by sputtering using an Ag target and a stainless steel target, respectively.

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