Film-coated transparent substrate and top plate for cooker

Abstract

Provided is a film-covered transparent substrate which exhibits excellent aesthetic properties when a light source is turned off and is unlikely to undergo a change in optical properties upon being heated.　A film-covered transparent substrate 1 which is provided with a transparent substrate 2 and a light-absorbing film 3 provided on a main surface 2a of the transparent substrate 2 on one side thereof, wherein the light-absorbing film 3 contains Ag, Al and Fe in proportions which result in a mole ratio of Ag:Al:Fe=x:y:z (wherein x+y+z=1, 0<x<1, 0<y<1, and 0≤z<1).

Description

[Technical Field]

[0001] The present invention relates to a film-coated transparent substrate and a top plate for a cooking appliance using the film-coated transparent substrate. [Background technology]

[0002] Conventionally, cookers such as induction cookers, radiant heater cookers, and gas cookers use top plates made of black glass or transparent glass coated with a black coating to conceal the internal structure of the cooker. These cookers often use a combination of LEDs (Light Emitting Diodes), liquid crystal displays, or liquid crystal displays with touch panel functionality on the top plate to display various information such as power and heating status.

[0003] Patent Document 1 below discloses a top plate for a cooking appliance, which includes 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 transparent resin portion that transmits LED light and a heat-resistant resin portion that blocks the LED light. In Patent Document 1, letters, numbers, symbols, etc. are displayed by changing the shape of the transparent portion that transmits LED light and by transmitting patterned light in the transparent portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-215018 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a top plate for a cooker is used in combination with an LED, a liquid crystal display, or a liquid crystal display having a touch panel function, etc., when the light source is lit, various information should be clearly visible, and when the light source is turned off, the structure inside the cooker is required to be hidden. However, when a glass substrate colored black is used as the top plate, although the structure inside the cooker can be hidden when the light source is turned off, there is a problem that various information is difficult to see when the light source is lit.

[0006] Regarding this point, in Patent Document 1, a black inorganic pigment layer is also provided in the display area, and an attempt is made to hide the structure inside the cooker thereby. However, when a black inorganic pigment layer is provided as in the top plate of Patent Document 1, it may not become achromatic black when the light source is turned off, and the aesthetic appearance may be impaired.

[0007] In addition, since the top plate for a cooker is repeatedly heated and used, high heat resistance is required. However, when a black inorganic pigment layer is provided as in the top plate of Patent Document 1, the optical properties may change due to heating. Therefore, also in this case, it may not become achromatic black when the light source is turned off, and the aesthetic appearance may be impaired.

[0008] An object of the present invention is to provide a transparent substrate with a film and a top plate for a cooker using the transparent substrate with a film, which are difficult to change in optical properties due to heating and have excellent aesthetic appearance when the light source is turned off.

Means for Solving the Problems

[0009] The transparent substrate with a film according to the present invention includes a transparent substrate and a light absorption film provided on one main surface of the transparent substrate, and the light absorption film contains Ag, Al, and Fe in a molar ratio of Ag:Al:Fe = x:y:z (where x + y + z = 1, 0 < x < 1, 0 < y < 1, 0 ≤ z < 1).

[0010] In the present invention, it is preferable that the light-absorbing film further contains O.

[0011] In the present invention, the content ratio of Al to the total of Al and Fe (y / (y+z)) is preferably 0.10 or more in molar ratio.

[0012] In the present invention, the content ratio of Ag to the total of Ag, Al, and Fe (x / (x+y+z)) is preferably 0.05 or more and 0.90 or less in molar ratio.

[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 Above, 80μm -1 It is preferable that:

[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 the α1 / α2 is 0.8 or more and 1.25 or less, and the α3 / α2 is 0.8 or more and 1.25 or less.

[0015] In the present invention, the light absorbing film has an absorption coefficient at a wavelength λ of α λ The average absorption coefficient in the wavelength range of 400 nm to 700 nm is α AVE When the above formula is used, it is preferable that the mean absorption deviation M shown in the following formula (1) is 0.30 or less.

[0016]

number

[0017] In the present invention, it is preferable that a dielectric multilayer film is further provided on the light absorbing film.

[0018] In the present invention, it is preferable that the transparent substrate is provided on one main surface thereof with a dielectric multilayer film including the light-absorbing film, the dielectric multilayer film being a laminated film in which high-refractive-index films having a relatively high refractive index and low-refractive-index films having a relatively low refractive index are alternately stacked, and at least one layer of the high-refractive-index films is the light-absorbing film.

[0019] In the present invention, it is preferable that the transparent substrate is provided on one main surface thereof with a dielectric multilayer film including the light-absorbing film, the dielectric multilayer film being a laminated film in which high-refractive-index films having a relatively high refractive index and low-refractive-index films having a relatively low refractive index are alternately stacked, and at least one layer of the low-refractive-index films is the light-absorbing film.

[0020] The top plate for a cooking appliance according to the present invention comprises a film-coated transparent substrate configured according to the present invention, the transparent substrate having a cooking surface on which a cooking utensil is placed and a back surface opposite the cooking surface, and the light-absorbing film is disposed on the back surface of the transparent substrate.

[0021] The cover glass according to the present invention is a cover glass used in a display, and is characterized in that it comprises a film-coated transparent substrate configured according to the present invention, and the light-absorbing film is disposed on a 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 whose optical properties are unlikely to change due to heating and which has an excellent aesthetic appearance when the light source is turned off, and a top plate for a cooking appliance using the film-coated transparent substrate. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a film-coated transparent substrate according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a schematic cross-sectional view showing a film-coated transparent substrate according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a film-coated transparent substrate according to a third embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fourth embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a top plate for a cooker according to one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the absorption coefficients of the light-absorbing films obtained in Examples 1 to 4 and Comparative Example 1 at wavelengths of 400 nm to 700 nm. [Figure 7] FIG. 7 is a diagram showing the transmission spectrum of the film-coated transparent substrate after the heat treatment in Example 3. As shown in FIG. [Figure 8] FIG. 8 is a diagram showing the transmission spectrum of the film-attached transparent substrate after the heat treatment in Comparative Example 1. As shown in FIG. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fifth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic cross-sectional view showing a cover glass according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0025] [Transparent substrate with film] (First embodiment) Fig. 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 Fig. 1, the film-coated transparent substrate 1 includes a transparent substrate 2 and a light-absorbing film 3. The transparent substrate 2 has a first main surface 2a and a second main surface 2b that face each other. 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, but the shape of the transparent substrate 2 is not particularly limited and may be a substantially circular plate shape.

[0027] The transparent substrate 2 transmits light in the wavelength range of 400 nm to 700 nm. The transparent substrate 2 may be colored and transparent, but is preferably colorless and transparent from the viewpoint of further enhancing aesthetic appeal. In this specification, "transparent" means that the light transmittance in the visible wavelength range of 400 nm to 700 nm is 80% or more. Furthermore, "colorless" means that the saturation of 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, but 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. A specific example of low-expansion crystallized glass is "N-0" manufactured by Nippon Electric Glass Co., Ltd. The transparent substrate 2 may also be made of borosilicate glass, alkali-free glass, aluminosilicate glass, or the like. In this case, the heat resistance of the transparent substrate 2 can be further improved, and the thermal expansion coefficient can be further reduced. Therefore, the transparent substrate 2 is suitable for use in applications such as top plates for cookware that are subjected to repeated heating and cooling.

[0030] There is no particular limitation on the thickness of the transparent substrate 2. The thickness of the transparent substrate 2 can be set appropriately depending on the light transmittance, etc. The thickness of the transparent substrate 2 can be, for example, about 0.035 mm to 5 mm.

[0031] The light absorption film 3 contains Ag, Al, and Fe in a molar ratio of Ag:Al:Fe = x:y:z (where x + y + z = 1, 0 < x < 1, 0 < y < 1, 0 ≤ z < 1). In particular, in this embodiment, the light absorption film 3 further contains O (oxygen). Specifically, when 0 < z < 1, the light absorption film 3 is a film containing Ag, aluminum oxide, and iron oxide. When z = 0, the light absorption film 3 is a film containing Ag and aluminum oxide.

[0032] The method for forming the light absorption film 3 is not particularly limited. For example, it can be formed by a physical vapor deposition method (PVD method), such as a sputtering method, a pulsed laser deposition method (PLD), or a vapor deposition method.

[0033] In the sputtering method or the pulsed laser deposition method (PLD), the light absorption film 3 can be formed, for example, using a mixed target of Ag, Al, and FeO. Alternatively, a mixed target of Ag and FeO and a target of Al can be used separately. Note that FeO may not be included in each target.

[0034] Also, for example, when forming a film by the sputtering method, the substrate temperature can be set to 15°C to 400°C, the flow rate of an inert gas such as argon gas as the sputtering gas can be set to 10 sccm to 1000 sccm, the flow rate of oxygen gas can be set to 0 sccm to 400 sccm, and the applied power can be set to 1 kW to 60 kW.

[0035] Since the transparent substrate 1 with a film of this embodiment has the above configuration, when the light source is lit, various information can be clearly visible, and when the light source is turned off, it can have excellent aesthetic properties. In particular, the optical properties are difficult to change even by heating, and excellent aesthetic properties 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 a substrate such as a top plate for a cooker, the internal structure of the cooker can be concealed when the light source, such as an LED or LCD display, is turned off, but when the light source is turned on, various information is difficult to see. On the other hand, when a black inorganic pigment layer is provided on a transparent substrate such as a glass substrate, the color does not become achromatic black when the light source is turned off, and aesthetics may be impaired.

[0037] In this regard, conventional top plates had the problem that the material that makes up the inorganic pigment layer strongly absorbs the short wavelength side of visible light (purple and blue sides; high light energy) and weakly absorbs the long wavelength side (red side; low light energy), preventing it from achieving an achromatic black color.

[0038] In contrast, in the light-absorbing film 3 of this embodiment, the short-wavelength side of visible light is absorbed by the band gap of iron oxide such as Fe2O3, and the long-wavelength side is absorbed by free electrons of Ag, so the top plate remains achromatic black even when the light is off, resulting in excellent aesthetics. Furthermore, by replacing part or all of the iron oxide with aluminum oxide, it is possible to improve heat resistance while maintaining the absorption of the short-wavelength side of visible light.

[0039] More specifically, the absorption coefficient α(λ) that depends on the wavelength of light is expressed 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)

[0041] (In formula (I), A, B, and C are constants, and n>0.)

[0042] That is, the absorption coefficient due to the band gap of iron oxide or the like, which absorbs light on the short wavelength side of visible light, is proportional to the nth power of the inverse of the wavelength, and the absorption coefficient due to free electrons in Ag, which absorbs light on the long wavelength side, is proportional to the square of the wavelength. Therefore, the absorption coefficient α(λ) of the light absorbing film 3, which is expressed as the sum of these, is generally independent of wavelength and tends to be a constant value at any wavelength.

[0043] Thus, the film-coated transparent substrate 1 provided with the light-absorbing film 3 can uniformly absorb light, particularly across almost the entire visible light range. Furthermore, its heat resistance is enhanced, so its optical properties are less likely to change due to heating. Therefore, the film-coated transparent substrate 1 can be made achromatic black when the light source is turned off, and is stable and has excellent aesthetics. Therefore, the film-coated transparent substrate 1 can be suitably used for applications such as top plates for cookware and cover glasses for displays.

[0044] In the light-absorbing film 3, the content ratio (y / (y+z)) of Al to the total of Al and Fe is preferably 0.10 or more, more preferably 0.30 or more, even more preferably 0.50 or more, and particularly preferably 0.60 or more, in molar ratio. When the content ratio (y / (y+z)) is equal to or more than the above-mentioned lower limit, it is possible to make it even more difficult for changes in optical properties due to heating to occur. The content ratio (y / (y+z)) may be 1.0 in molar ratio.

[0045] In the light-absorbing film 3, the content ratio of Ag to the total of Ag, Al, and Fe (x / (x+y+z)) is, in molar ratio, preferably 0.05 or more, more preferably 0.12 or more, and preferably 0.90 or less, more preferably 0.80 or less. When the content ratio (x / (x+y+z)) is within the above range, it is possible to appropriately increase light absorption on the long wavelength side of visible light, to more uniformly absorb light across almost the entire visible light range, and to obtain even higher electrical insulation.

[0046] In the light-absorbing film 3, the content ratio (y / (x+y+z)) of Al to the total of Ag, Al, and Fe is preferably 0.04 or more, more preferably 0.27 or more, and preferably 0.95 or less, more preferably 0.80 or less, in molar ratio. When the content ratio (y / (x+y+z)) is within the above range, it is possible to make it even more difficult for changes in optical properties due to heating to occur.

[0047] In the light-absorbing film 3, the content ratio (z / (x+y+z)) of Fe to the total of Ag, Al, and Fe is preferably 0.08 or more, more preferably 0.18 or more, and preferably 0.76 or less, more preferably 0.64 or less, in molar ratio. When the content ratio (z / (x+y+z)) is within the above range, it is possible to appropriately increase light absorption on the short wavelength side of visible light, and to more uniformly absorb light over almost the entire visible light range.

[0048] The contents of Ag, Al, and Fe in the light-absorbing film 3 can be measured by energy dispersive X-ray analysis, wavelength dispersive X-ray analysis, inductively coupled plasma mass spectrometry, or the like.

[0049] In the present invention, it is preferable that aluminum oxide and / or iron oxide constitute a matrix in the light-absorbing film 3, with Ag dispersed in the matrix. In this case, the insulating properties of the light-absorbing film 3 can be further improved. Note that a portion of Ag may be present as a matrix component, as long as the insulating properties are maintained. Therefore, in this case, the film can be suitably used for displays with touch panel functions or top plates for cookers incorporating displays with touch panel functions.

[0050] The average absorption coefficient of the light absorbing film 3 at wavelengths of 400 nm to 700 nm is preferably 0.5 μm -1 More preferably, 10 μm -1 More than 80 μm, preferably -1 Less than or equal to 70 μm, more preferably -1or less. If the average absorption coefficient is equal to or greater than the above lower limit, when used, for example, 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 equal to or less than the above upper limit, various information displays can be more reliably and clearly seen when the light source is turned on. The absorption coefficient of the light-absorbing film 3 is derived from measurements of transmittance and reflectance using spectroscopic ellipsometry or a spectrophotometer, and in this case, measurements are taken from the light-absorbing film 3 side when the film is laminated on the transparent substrate 2.

[0051] Furthermore, in the light-absorbing film 3, where α1 is the absorption coefficient at a wavelength of 436 nm, α2 is the absorption coefficient at a wavelength of 546 nm, and α3 is the absorption coefficient at a wavelength of 700 nm, it is preferable that α1 / α2 is 0.8 to 2.0, and α3 / α2 is 0.8 to 2.0. It is more preferable that α1 / α2 is 0.8 to 1.25, and α3 / α2 is 0.8 to 1.25. In this case, a more achromatic black color can be achieved when the light source is turned off, resulting in even more aesthetically pleasing appearance.

[0052] In addition, 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 α AVE When the average absorption deviation M is 0.30 or less, the average absorption deviation M is preferably 0.30 or less, as shown in the following formula (1). In this case, a more achromatic black color can be obtained when the light source is turned off, and the appearance can be further improved.

[0053]

number

[0054] In the present invention, the Ag content in the light-absorbing film 3 is, in mol %, preferably 5% or more, more preferably 10% or more, even more preferably 12% or more, preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, and particularly preferably 55% or less. If the Ag content in the light-absorbing film 3 is less than the above-mentioned lower limit, the α1 / α2 may become too large, the α3 / α2 may become too small, and the absorption mean deviation M may become too large. On the other hand, if the Ag content in the light-absorbing film 3 is greater than the above-mentioned upper limit, the sheet resistance may be easily reduced. Furthermore, the α1 / α2 may become too small, the α3 / α2 may become too large, and the absorption mean deviation M may become too large.

[0055] 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, and preferably 2 μm or less, more preferably 1 μm or less, even more preferably 500 nm or less, particularly preferably 100 nm or less. When the thickness of the light-absorbing film 3 is within the above range, various pieces of information can be displayed more clearly when the light source is turned on, and the appearance can be made even more excellent when the light source is turned off.

[0056] Saturation C of transmitted light through the film-coated transparent substrate 1 * T is preferably 2 or less, more preferably 1 or less, even more preferably 0.8 or less, and particularly preferably 0.5 or less. * T The lower limit of is not particularly limited, but is, for example, 0. Furthermore, the saturation C of the reflected light of the film-coated transparent substrate 1 * R is preferably 2 or less, more preferably 1 or less, even more preferably 0.7 or less, and particularly preferably 0.5 or less. * R The lower limit of the saturation C is not particularly limited, but is, for example, 0. *is the saturation C when illuminated with a D65 light source in the L*a*b* color system adopted in JIS Z 8781-4:2013. * In addition, saturation C * is chromaticity a * and b * More demanding, C * =((a * ) 2 +(b * ) 2 ) 1 / 2 In this case, it is possible to achieve a more achromatic black color when the light source is turned off, and it is possible to achieve an even more aesthetically pleasing appearance.

[0057] In order to make the boundary between the display area A and the non-display area B, which will be described later, even more difficult to see, the brightness (L * The absolute value of the difference between the brightness (L * The lower limit of the absolute value of the difference between the saturation (C * R The absolute value of the difference between the saturation (C) of the reflected light in the display area A and the non-display area B is preferably 0.7 or less, more preferably 0.4 or less, and further preferably 0.3 or less. * R The lower limit of the absolute value of the difference between

[0058] The 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 7In this case, since the light absorbing film 3 is insulating, when it is used as a cover glass for an image display device or a top plate for a cooking appliance, even if a touch panel is attached, the change in capacitance due to finger contact required for a capacitive touch sensor is maintained, and the touch panel can function. Note that the upper limit of the sheet resistance of the light absorbing film 3 is, for example, 10 15 Ω(10 15 The sheet resistance can be measured by the method specified in ASTM D257 or JIS K 6271-6 (2008).

[0059] (Second to fifth embodiments) Fig. 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 Fig. 2, a film-coated transparent substrate 21 further includes a dielectric multilayer film 6 on a light-absorbing film 3. Other points are the same as those in the first embodiment.

[0060] The dielectric multilayer film 6 is a laminated film in which low-refractive-index films 7, which have a relatively low refractive index, and high-refractive-index films 8, which have a relatively high refractive index, are alternately laminated in this order. In this embodiment, the number of laminated layers in the dielectric multilayer film 6 is five. When the outermost layer is the low-refractive-index film 7, as in this embodiment, the function as an anti-reflection film can be further improved.

[0061] The low refractive index film 7 may be made of, for example, silicon oxide as in this embodiment, or aluminum oxide.

[0062] Examples of materials for the high refractive index film 8 include niobium oxide, titanium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silicon nitride, aluminum oxide, and aluminum nitride, as in this embodiment.

[0063] Fig. 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 Fig. 3, a film-coated transparent substrate 31 has a dielectric multilayer film 16 including a light-absorbing film 3 provided on a first main surface 2a of a transparent substrate 2. Other points are the same as those of the first embodiment.

[0064] In the dielectric multilayer film 16, low-refractive-index films 7 having a relatively low refractive index and light-absorbing films 3 serving as high-refractive-index films having a relatively high refractive index are alternately stacked in this order. In this embodiment, the dielectric multilayer film 16 has five stacked layers. The light-absorbing films 3 are the light-absorbing films 3 described in the first embodiment, and the low-refractive-index films 7 are the low-refractive-index films 7 described in the second embodiment. At least one of the two light-absorbing films 3 may be the high-refractive-index film 8 described in the second embodiment.

[0065] Fig. 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 Fig. 4, in a film-coated transparent substrate 41, two light-absorbing films 3 are provided on a transparent substrate 2, and a dielectric multilayer film is further provided between the transparent substrate 2 and the light-absorbing films 3 and between the two light-absorbing films 3, 3. Other points are the same as those in the second embodiment.

[0066] Fig. 9 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fifth embodiment of the present invention. As shown in Fig. 9, a film-coated transparent substrate 61 has a dielectric multilayer film 66 including a light-absorbing film 3 provided on a first main surface 2a of a transparent substrate 2. Other points are the same as those of the first embodiment.

[0067] In the dielectric multilayer film 66, high refractive index films 8 having a relatively high refractive index and light absorbing films 3 serving as low refractive index films having a relatively low refractive index are alternately laminated in this order. In addition, a low refractive index film 7, which is a silicon oxide film (SiO2 film), is provided as the outermost layer. When the low refractive index film 7, which is a silicon oxide film (SiO2 film), is provided as the outermost layer, it is possible to further improve oxidation resistance, sulfur resistance, weather resistance, and the like.

[0068] In this embodiment, the number of layers stacked in the dielectric multilayer film 66 is six. The light-absorbing film 3 is the light-absorbing film 3 described in the first embodiment, and the high-refractive-index film 8 is the high-refractive-index film 8 described in the second embodiment. One of the two light-absorbing films 3 may be the low-refractive-index film 7 described in the second embodiment.

[0069] In the second to fifth embodiments as well, the light absorption film 3 contains Ag, Al, and Fe in a molar ratio of Ag:Al:Fe = x:y:z (where x + y + z = 1, 0 < x < 1, 0 < y < 1, 0 ≤ z < 1). Therefore, when the light source is lit, various information can be clearly visible, and when the light source is turned off, it can have excellent aesthetics. In particular, the optical properties are difficult to change even by heating, and it can stably have excellent aesthetics when the light source is turned off.

[0070] Also, a dielectric multilayer film 6 may be provided on the light absorption film 3 as in the second embodiment, or a dielectric multilayer film including the light absorption film 3 may be provided on the transparent substrate 2 as in the third and fifth embodiments, or two layers of the light absorption film 3 may be provided on the transparent substrate 2 as in the fourth embodiment, and a dielectric multilayer film may be further provided between the transparent substrate 2 and the light absorption film 3 and between the two light absorption films 3, 3. When such a dielectric multilayer film is provided, for example, an antireflection function can be further imparted. In this case, the contrast of the display can also be improved.

[0071] At this time, as in the third embodiment, the light absorption film 3 may be used as a high refractive index film, or as in the fifth embodiment, the light absorption film 3 may be used as a low refractive index film. The refractive index of the light absorption film 3 can be adjusted according to film formation conditions such as the target composition and film formation pressure, and it can be used as a low refractive index film or a high refractive index film. Note that the refractive index of the light absorption film 3 can be adjusted, for example, in the range of 1.2 or more and 2.0 or less.

[0072] Also, in the dielectric multilayer film of each embodiment, the total number of layers of the low refractive index film 7 and the high refractive index film 8 can be, for example, 2 layers or more and 40 layers or less. The thickness of the low refractive index film 7 can be, for example, 5 nm or more and 300 nm or less per layer. Also, the thickness of the high refractive index film 8 can be, for example, 3 nm or more and 200 nm or less per layer. When the light absorption film 3 is used, the thickness described in the first embodiment may be used.

[0073] [Cooking appliance top plate] 5 is a schematic cross-sectional view showing a top plate for a cooker according to one embodiment of the present invention. As shown in FIG. 5, a top plate 51 for a cooker includes a transparent substrate 1 with a film.

[0074] In the top plate 51 for a cooker, 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 cooking utensils such as pots and frying pans are placed. The back surface is the surface facing the light source 52 such as an LED or a display and the heating device inside the cooker. 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.

[0075] 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 53 is provided on the light-absorbing film 3. The heat-resistant resin layer 53 may be provided between the transparent substrate 2 and the light-absorbing film 3. In this embodiment, in plan view, the region where the heat-resistant resin layer 53 is not provided is defined as a display region A. In plan view, the region where the heat-resistant resin layer 53 is provided is defined as a non-display region B.

[0076] The heat-resistant resin layer 53 is a light-blocking layer. Therefore, by providing the heat-resistant resin layer 53, the concealment of the internal structure of the cooking appliance can be further improved. The heat-resistant resin layer 53 can be composed of a heat-resistant resin such as silicone resin and a coloring pigment, etc. Note that the heat-resistant resin layer 53 does not necessarily have to be provided.

[0077] A light source 52 such as a display or an LED is provided below the film-coated transparent substrate 1. The light source 52 is a member provided to display information in the display area A. The information displayed in the display area A is not particularly limited, and examples include information indicating the state of the cooker, such as whether the power is on or heating, and information such as time.

[0078] In the display area A, light from the light source 52 passes through the light absorbing film 3 and the transparent substrate 2 and is emitted to the outside. In the non-display area B, the light from the light source 52 is blocked by the heat-resistant resin layer 53. Therefore, in the display area A, by transmitting the light from the light source 52, it is possible to display letters, numbers, symbols, etc.

[0079] The top plate 51 for the cooker includes a film-coated transparent substrate 1. Therefore, when the light source 52 is turned on, various pieces of information can be displayed clearly, and when the light source 52 is turned off, the top plate 51 can have an excellent aesthetic appearance. Furthermore, the internal structure of the cooker can be concealed while making the boundary between the display area A and the non-display area B less visible. A display with a touch panel function may be built into the cooker.

[0080] (cover glass) Fig. 10 is a schematic cross-sectional view showing a cover glass according to one embodiment of the present invention. As shown in Fig. 10, the cover glass 71 includes a film-coated transparent substrate 1. The cover glass 71 is a cover glass that is used, for example, by being placed on the front surface of a display.

[0081] In the cover glass 71, the first main surface 2a of the transparent substrate 2 constituting the film-coated transparent substrate 1 is the main surface disposed on the outside. On the other hand, the second main surface 2b of the transparent substrate 2 constituting the film-coated 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 (first main surface 2a) of the transparent substrate 2 opposite to the side on which the display is provided.

[0082] The cover glass 71 also has the film-coated transparent substrate 1, so that its optical properties are less likely to change due to heating, and it has an excellent aesthetic appearance when the light source is turned off.

[0083] Also, the cover glass 71 may have an anti-reflection film formed thereon using a dielectric multilayer film as described in the second to fifth embodiments.

[0084] The present invention will be described in more detail below based on examples. However, the following examples are merely illustrative and the present invention is not limited to the following examples.

[0085] Example 1 In Example 1, a light-absorbing film was formed on a transparent glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name "N-0", thickness: 4 mm) by sputtering using a mixed target of Ag, Al, and FeO. The Ag content in the mixed target was 60 mol %. The substrate temperature was 300°C, and the oxygen partial pressure was 0.5 Pa. The Ag content in the light-absorbing film was 88 mol %. The content ratio of Al to the total of Al and Fe (y / (y+z)) (Al / (Al+Fe)) was 0.14 in molar ratio. The compositions of Ag, Al, and Fe were measured by inductively coupled plasma mass spectrometry.

[0086] (Examples 2 to 4 and Comparative Example 1) A light-absorbing film was formed in the same manner as in Example 1, except that the target composition was changed so that the content of Al relative to the total of Al and Fe (y / (y+z)) was as shown in Table 1 below in molar ratio.

[0087] [evaluation] (Optical properties) Fig. 6 is a diagram showing the absorption coefficients in the wavelength range of 400 nm to 700 nm of the light-absorbing films obtained in Examples 1 to 4 and Comparative Example 1. Fig. 6 shows that the light-absorbing films obtained in Examples 1 to 4 have an almost constant absorption coefficient in the wavelength range of 400 nm to 700 nm, similar to the light-absorbing film obtained in Comparative Example 1. In the light-absorbing films obtained in Examples 1 to 4 and Comparative 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, α1 / α2, α3 / α2, and the average absorption coefficient α AVE The mean absorption deviation M was as shown in Table 1 below. In Tables 1 and 2, (y / (y+z)) is expressed as (Al / (Al+Fe)).

[0088] (Saturation and brightness) Chroma C of transmitted light through the film-coated transparent substrates obtained in Examples 1 to 4 and Comparative Example 1 * T and the saturation of reflected light C * R Chroma C * is based on JIS Z 8781-4:2013 and is the saturation of transmitted light C * T was measured using a spectrophotometer (Hitachi High-Tech Science Corporation, model number U-4100), and the saturation of reflected light C * R is measured using a color difference meter (Konica Minolta, "CM2600d") when irradiating a D65 light source from the opposite side of the film deposition surface (L * ), chromaticity (a * and b * ) and evaluate the formula: C * =((a * ) 2 +(b * ) 2 ) 1 / 2 The saturation of transmitted light, C * T , saturation of reflected light C * R The results are shown in Table 1 below.

[0089] The portion of the film-coated transparent substrate on which the light-absorbing film was formed was designated the display area, and a 15 μm-thick heat-resistant resin layer was separately formed on the light-absorbing film, and the portion on which this heat-resistant resin layer was formed was designated the non-display area. The heat-resistant resin layer was prepared by mixing 34 parts by mass of silicone resin, 29 parts by mass of black pigment, and 37 parts by mass of solvent to prepare a paste, and applying it onto the light-absorbing film.

[0090] For the display area and non-display area obtained as described above, the saturation C of the reflected light between the display area and the non-display area is * R The absolute value of the difference between the * The absolute value of the difference between

[0091] (sheet resistance) The sheet resistance of the film-coated transparent substrates obtained in Examples 1 to 4 and Comparative Example 1 was measured by a direct current two-terminal method using platinum electrodes. The results are shown in Table 1 below.

[0092] [Table 1]

[0093] (Heat resistance test) The film-coated transparent substrates obtained in Example 3 and Comparative Example 1 were heat-treated for 10 minutes at temperatures of 100°C, 200°C, and 300°C, respectively. The transmittance differences at wavelengths of 436 nm, 546 nm, and 700 nm for the samples heat-treated at 100°C compared to unheat-treated samples were measured. The results are shown in Table 2 below.

[0094] [Table 2]

[0095] Fig. 7 is a diagram showing the transmission spectrum of the film-coated transparent substrate after the heat treatment of Example 3. Fig. 8 is a diagram showing the transmission spectrum of the film-coated transparent substrate after the heat treatment of Comparative Example 1. Note that Figs. 7 and 8 also show the transmission spectrum of the film-coated transparent substrate before the heat treatment.

[0096] 7, it can be seen that the optical properties of the film-coated transparent substrate of Example 3 remain almost unchanged regardless of the temperature at which the heat treatment is performed. On the other hand, it can be seen from Table 2 and Fig. 8 that the optical properties of the film-coated transparent substrate of Comparative Example 1 change significantly due to the heat treatment.

[0097] It has been confirmed that, similarly to Example 3, the optical properties of the film-attached transparent substrates of Examples 1, 2 and 4 remain almost unchanged regardless of the temperature at which the heat treatment is performed.

[0098] It was confirmed that the film-coated transparent substrates of Examples 1 to 4 were resistant to changes in optical properties due to heating and had excellent aesthetic appearance even when the light source was turned off.

[0099] Example 5 A dielectric multilayer film was fabricated by sputtering on a transparent glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name "T2X-1", thickness: 1.3 mm, refractive index: 1.52 (wavelength 550 nm)). Specifically, the dielectric multilayer film was fabricated in the configuration shown in Table 3 below, with the light absorbing film of Example 3, a niobium oxide film (Nb2O5) film, the light absorbing film of Example 3, and a silicon oxide film (SiO2 film) alternately stacked in this order on the glass substrate. The refractive index is the refractive index at a wavelength of 550 nm.

[0100] [Table 3]

[0101] The transmission spectrum and reflection spectrum of the film-coated transparent substrate obtained in Example 5 were measured from the film-formed surface side using a spectrophotometer (Hitachi High-Tech Science Corporation, product number "U-4100"). Specifically, the angles of incidence (AOI) were set to 0°, 15°, 30°, and 45°, and the measurement wavelength range was set to 380 nm to 780 nm. From the obtained transmittance spectrum and reflectance spectrum, the luminous reflectance, luminous transmittance, and lightness (L) of reflected light and transmitted light when irradiated with a D65 light source were determined. * ), chromaticity (a * and b * The results are shown in Table 4 below.

[0102] [Table 4]

[0103] Example 6 A dielectric multilayer film was fabricated by sputtering on a transparent glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name "T2X-1", thickness: 1.3 mm, refractive index: 1.52 (wavelength 550 nm)). Specifically, the dielectric multilayer film was fabricated in the configuration shown in Table 5 below, with a silicon nitride film (SiN film), the light absorbing film of Example 3, a SiN film, the light absorbing film of Example 3, a SiN film, and an SiO2 film alternately stacked in this order on the glass substrate. The refractive index is the refractive index at a wavelength of 550 nm.

[0104] [Table 5]

[0105] The transmission spectrum and reflection spectrum of the film-coated transparent substrate obtained in Example 6 were measured from the film-formed surface side using a spectrophotometer (Hitachi High-Tech Science Corporation, product number "U-4100"). Specifically, the angles of incidence (AOI) were set to 0°, 15°, 30°, and 45°, and the measurement wavelength range was set to 380 nm to 780 nm. From the obtained transmittance spectrum and reflectance spectrum, the luminous reflectance, luminous transmittance, and lightness (L) of reflected light and transmitted light when irradiated with a D65 light source were determined. * ), chromaticity (a * and b * The results are shown in Table 6 below.

[0106] [Table 6]

[0107] Example 7 A dielectric multilayer film was fabricated by sputtering on a transparent glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name "N-0", thickness: 4 mm, refractive index: 1.54 (wavelength 550 nm)). Specifically, the dielectric multilayer film was fabricated in the configuration shown in Table 7 below, with an Nb2O5 film, the light-absorbing film of Example 3, an Nb2O5 film, the light-absorbing film of Example 3, and an SiO2 film alternately stacked in this order on a glass substrate 2. The refractive index is the refractive index at a wavelength of 550 nm.

[0108] [Table 7]

[0109] The transmission spectrum and reflection spectrum of the film-coated transparent substrate obtained in Example 7 were measured from the side opposite to the film-formed surface using a spectrophotometer (Hitachi High-Tech Science Corporation, product number "U-4100"). Specifically, the angles of incidence (AOI) were set to 0°, 15°, 30°, and 45°, and the measurement wavelength range was set to 380 nm to 780 nm. From the obtained transmittance spectrum and reflectance spectrum, the luminous reflectance, luminous transmittance, and lightness (L) of reflected light and transmitted light when irradiated with a D65 light source were determined. * ), chromaticity (a * and b * The results are shown in Table 8 below.

[0110] [Table 8]

[0111] Example 8 A dielectric multilayer film was fabricated by sputtering on a transparent glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name "N-0", thickness: 4 mm, refractive index: 1.54 (wavelength 550 nm)). Specifically, the dielectric multilayer film was fabricated in the configuration shown in Table 9 below, with a SiN film, the light absorbing film of Example 3, a SiN film, the light absorbing film of Example 3, and a SiN film alternately stacked in this order on the glass substrate. The refractive index is the refractive index at a wavelength of 550 nm.

[0112] [Table 9]

[0113] The transmission spectrum and reflection spectrum of the film-coated transparent substrate obtained in Example 8 were measured from the side opposite to the film-formed surface using a spectrophotometer (Hitachi High-Tech Science Corporation, product number "U-4100"). Specifically, the angles of incidence (AOI) were set to 0°, 15°, 30°, and 45°, and the measurement wavelength range was set to 380 nm to 780 nm. From the obtained transmittance spectrum and reflectance spectrum, the luminous reflectance, luminous transmittance, and lightness (L) of reflected light and transmitted light when irradiated with a D65 light source were determined. * ), chromaticity (a * and b * The results are shown in Table 10 below.

[0114] [Table 10]

[0115] From Tables 4, 6, 8, and 10, the film-coated transparent substrates obtained in Examples 5 to 8 were * and b * The film-coated transparent substrates obtained in Examples 5 to 8 had a small reflection color and a neutral transmission color. * and b * It was confirmed that the color hardly changes and there is almost no color shift in the incident angle range of 0° to 45°. [Explanation of symbols]

[0116] 1, 21, 31, 41, 61...Transparent substrate with film 2...Transparent substrate 2a...first principal surface 2b...Second main surface 3...Light absorbing film 6,16,66...Dielectric multilayer film 7...Low refractive index film 8...High refractive index film 51...Cooker top plate 52...Light source 53...Heat-resistant resin layer 71...Cover glass

Claims

1. A transparent substrate; a light absorbing film provided on one main surface of the transparent substrate; Equipped with the light-absorbing film contains Ag, aluminum oxide, and iron oxide; the light-absorbing film contains Ag, Al, and Fe in a molar ratio of Ag:Al:Fe=x:y:z (where x+y+z=1, 0<x<1, 0<y<1, 0<z<1), The film-attached transparent substrate, wherein in the light-absorbing film, the content ratio of Ag to the total of Ag, Al, and Fe (x / (x+y+z)) is 0.12 or more and 0.90 or less in molar ratio.

2. 2. The film-attached transparent substrate according to claim 1, wherein the content ratio of Al to the total of Al and Fe (y / (y+z)) is 0.10 or more in molar ratio.

3. The average absorption coefficient of the light-absorbing film at wavelengths of 400 nm to 700 nm is 0.5 μm －１ Above, 80μm －１ The film-coated transparent substrate according to claim 1 or 2, wherein:

4. 4. The film-provided transparent substrate according to claim 1, wherein, in the light-absorbing film, when an absorption coefficient at a wavelength of 436 nm is defined as α1, an absorption coefficient at a wavelength of 546 nm is defined as α2, and an absorption coefficient at a wavelength of 700 nm is defined as 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.

5. 5. The film-attached transparent substrate according to claim 4, wherein in the light-absorbing film, the α1 / α2 is 0.8 or more and 1.25 or less, and the α3 / α2 is 0.8 or more and 1.25 or less.

6. In the light absorbing film, the absorption coefficient at wavelength λ is α λ and the average absorption coefficient in the wavelength range of 400 nm to 700 nm is α ＡＶＥ 6. The film-attached transparent substrate according to claim 1, wherein the mean absorption deviation M represented by the following formula (1) is 0.30 or less when: [Equation 1]

7. 7. The film-coated transparent substrate according to claim 1, further comprising a dielectric multilayer film provided on the light-absorbing film.

8. a dielectric multilayer film provided on one main surface of the transparent substrate and including the light absorbing film; the dielectric multilayer film is a laminated film in which high-refractive-index films having a relatively high refractive index and low-refractive-index films having a relatively low refractive index are alternately laminated, 7. The film-coated transparent substrate according to claim 1, wherein at least one layer of said high refractive index films is said light absorbing film.

9. a dielectric multilayer film provided on one main surface of the transparent substrate and including the light absorbing film; the dielectric multilayer film is a laminated film in which high-refractive-index films having a relatively high refractive index and low-refractive-index films having a relatively low refractive index are alternately laminated, 7. The film-coated transparent substrate according to claim 1, wherein at least one layer of said low refractive index films is said light absorbing film.

10. A transparent substrate with a film according to any one of claims 1 to 9 is provided, the transparent substrate has a cooking surface on which a cooking utensil is placed and a back surface opposite to the cooking surface; The top plate for a cooking appliance, wherein the light-absorbing film is disposed on the back surface of the transparent substrate.

11. A cover glass for use in a display, comprising: A transparent substrate with a film according to any one of claims 1 to 9 is provided, a cover glass, the light-absorbing film being disposed on a main surface of the transparent substrate opposite to a surface on which a display is provided;

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