JP2023092191A - Transparent substrate with film, top plate for cooker, window glass for heating cooker, and cover glass - Google Patents

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 The present invention relates to a film-coated transparent substrate, a cooker top plate, a heating cooker window glass, and a cover glass using the film-coated transparent substrate.

Conventionally, in cookers such as electromagnetic cookers, radiant heater cookers, and gas cookers, a top plate made of black glass or transparent glass with a black coating film is used to hide the internal structure of the cooker. is used. In such cookers, a combination of LEDs (Light Emitting Diodes), liquid crystal displays, or liquid crystal displays having a touch panel function is sometimes used in order to display various information such as power supply and heating state on the top plate. .

Patent Document 1 below discloses a cooker top plate that 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 pigment and glass. The display layer has a transmission portion that transmits LED light and the like, and a heat-resistant resin portion that blocks the LED light and the like. In Patent Document 1, letters, numerals, symbols, and the like are displayed by changing the shape of a transmission portion that transmits LED light or the like, or by transmitting patterned light in the transmission portion.

JP 2014-215018 A

By the way, when a combination of LED, liquid crystal display, or liquid crystal display having a touch panel function is used for the cooker top plate, various information can be clearly seen when the light source is turned on, and the cooker can be displayed when the light source is turned off. Concealment of the internal structure is required. However, when a black-colored glass substrate is used as the top plate, although the internal structure of the cooker can be concealed when the light source is turned off, various information is difficult to see when the light source is turned on.

Regarding this point, in Patent Document 1, a black inorganic pigment layer is provided also in the display area, thereby attempting to conceal the structure inside the cooker. However, when a black inorganic pigment layer is provided as in the top plate of Patent Literature 1, the color is not achromatic black when the light source is turned off, and the aesthetic appearance may be impaired.

Moreover, since the top plate for cookers is repeatedly heated and used, it is required to have high heat resistance. However, when a black inorganic pigment layer is provided as in the top plate of Patent Document 1, the optical characteristics may change due to heating, and the color may change. Therefore, when the light source is turned off, the desired black color may not be obtained, and the aesthetic appearance may be impaired.

An object of the present invention is to provide a film-coated transparent substrate that does not easily change in color even when heated to a high temperature, such as a top plate for a cooker, and that is excellent in aesthetics when the light source is turned off, and to use the film-coated transparent substrate. To provide a top plate for a cooking device which has been heated, a window glass for a heating cooking device, and a cover glass.

A 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. It is characterized by

In the present invention, it is preferable that the light absorption film further contains O.

In the present invention, the mass ratio of Cr to Fe (Cr/Fe) is preferably 0.10 or more and 0.60 or less.

In the present invention, it is preferable that the light absorption film has a matrix containing Fe, Cr, and O, and the Ag is dispersed in the matrix.

In the present invention, it is preferable that the light absorption film has an average absorption coefficient of 0.5 μm ⁻¹ or more and 80 μm ⁻¹ or less at a wavelength of 400 nm to 700 nm.

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, α1/α2 is 0.8 or more, 2.0 or less, and α3/α2 is preferably 0.8 or more and 2.0 or less. More preferably, 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 the present invention, in the light-absorbing film, when the absorption coefficient at a wavelength λ is α _λ and the average absorption coefficient at a wavelength of 400 nm to 700 nm is α _AVE , the absorption average deviation M represented by the following formula (1) is It is preferably 0.30 or less.

In the present invention, a dielectric multilayer film may be further provided on the light absorbing film.

In the present invention, a dielectric multilayer film including the light absorption film may be provided on the transparent substrate. The dielectric multilayer film may be a laminated film in which a high refractive index film having a relatively high refractive index and a low refractive index film having a relatively low refractive index are alternately laminated. At this time, at least one layer of the high refractive index film may be the light absorption film. At least one of the low refractive index films may be the light absorption film.

A cooker top plate 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 to the cooking surface, The light absorbing film is provided on the back surface of the transparent substrate.

A window glass for a cooking device according to the present invention is a window glass for use in a cooking device, comprising a film-coated transparent substrate configured according to the present invention, wherein the main transparent substrate on the heating device side of the cooking device is a transparent substrate. It is characterized in that the light absorbing film is arranged on the surface.

A cover glass according to the present invention is a cover glass used for a display, and comprises a film-coated transparent substrate configured according to the present invention, and on the main surface of the transparent substrate opposite to the side on which the display is provided, It is characterized in that the light absorbing film is arranged.

According to the present invention, a film-coated transparent substrate that does not easily change in color even when heated to a high temperature, such as a top plate for a cooker, and has excellent aesthetics when the light source is turned off, and the film-coated transparent substrate are used. A cooker top plate, a heat cooker window glass, and a cover glass can be provided.

FIG. 1 is a schematic cross-sectional view showing a film-coated transparent substrate according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a film-coated transparent substrate according to a second embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a film-coated transparent substrate according to a third embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fourth embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a film-coated transparent substrate according to a fifth embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing a cooker top plate according to one embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing a cover glass according to one embodiment of the invention. 8 is a diagram showing the transmission spectrum of the film-coated transparent substrate after heat treatment in Example 1. FIG. 9 is a diagram showing a transmission spectrum of a film-coated transparent substrate after heat treatment in Comparative Example 1. FIG. 10 is a diagram showing the relationship between the heat treatment temperature and the amount of change in a ^* and b ^* before and after the heat treatment in the film-coated transparent substrate of Example 1. FIG. 11 is a diagram showing the relationship between the heat treatment temperature and the amount of change in a ^* and b ^* before and after the heat treatment in the film-coated transparent substrate of Comparative Example 1. FIG. FIG. 12 is a diagram showing the relationship between the heat treatment temperature of the film-coated transparent substrate of Example 1 and the amount of change in x and y before and after the heat treatment. 13 is a diagram showing the relationship between the heat treatment temperature and the amount of change in x and y before and after the heat treatment in the film-coated transparent substrate of Comparative Example 1. FIG.

Preferred embodiments are described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Also, in each drawing, members having substantially the same function may be referred to by the same reference numerals.

[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 absorption film 3 . The transparent substrate 2 has a first major surface 2a and a second major surface 2b facing each other. A light absorbing film 3 is provided on the first main surface 2 a of the transparent substrate 2 .

In this embodiment, the transparent substrate 2 has a substantially rectangular plate shape. However, the transparent substrate 2 may have a substantially disk-like shape, and the shape is not particularly limited.

The transparent substrate 2 transmits light with a wavelength of 400 nm to 700 nm. Although the transparent substrate 2 may be colored and transparent, it is preferably colorless and transparent from the viewpoint of further enhancing aesthetics. In this specification, "transparent" means that the average light transmittance in the visible wavelength range is 80% or more at a wavelength of 400 nm to 700 nm. Further, "colorless" means that the saturation of transmitted light is 2 or less when irradiated with a D65 light source.

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.

The glass forming the transparent substrate 2 is preferably made of low-expansion glass or low-expansion crystallized glass having a high glass transition temperature. As the transparent substrate 2, borosilicate glass, alkali-free glass, aluminosilicate glass, or the like may be used. A specific example of the 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 improved, and the thermal expansion coefficient can be further reduced. Therefore, it can be suitably used for applications such as a top plate for a cooker (hereinafter simply referred to as "top plate") in which heating and cooling are repeated.

The thickness of the transparent substrate 2 is not particularly limited. The thickness of the transparent substrate 2 can be appropriately set according to the light transmittance and the like. The thickness of the transparent substrate 2 can be, for example, about 0.035 mm to 5 mm.

The light absorption film 3 contains Ag, Fe, and Cr. In particular, in this embodiment, the light absorbing film 3 further contains O (oxygen). Specifically, the light absorption film 3 is a film containing Ag, iron oxide, and chromium oxide. In addition, the light absorbing film 3 may contain nickel oxide, molybdenum oxide, copper oxide, or the like.

The method for forming the light absorption film 3 is not particularly limited, but for example, it may be formed by a physical vapor deposition method (PVD method), a sputtering method, a pulse laser deposition method (PLD), or a vapor deposition method. can be done.

In the sputtering method or the pulse laser deposition method (PLD), the light absorption film 3 can be formed using a mixed target of Ag and stainless steel, for example. Also, an Ag target and a stainless target may be used separately. Note that stainless steel is an alloy steel having 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. As stainless steel, for example, SUS304, SUS301, SUS316 or the like can be used. When a stainless steel target is used, the magnetism is lower than that of an Fe target, so that the discharge is stabilized and the film can be formed more stably. In particular, when an austenitic stainless steel target is used, since it is non-magnetic (paramagnetic), discharge is stabilized, and particularly stable film formation can be achieved.

When forming a film by a sputtering method, for example, the substrate temperature is 15 to 400° C., the flow rate of an inert gas such as argon gas as a sputtering gas is 10 sccm to 1000 sccm, and the oxygen gas flow rate is 0 sccm to 400 sccm. can be performed at 1 kW to 60 kW.

Since the film-coated transparent substrate 1 of the present embodiment has the above-described configuration, it is possible to make the display of various information clearly visible when the light source is turned on, and to have excellent aesthetics when the light source is turned off. . In particular, when heated to a high temperature such as a top plate for a cooker, the color does not easily change, and excellent aesthetics can be stably maintained when the light source is turned off. This point can be explained as follows.

Conventionally, when a black-colored glass substrate is used for a substrate such as a top plate for a cooker, the structure inside the cooker can be hidden when the light source such as an LED or liquid crystal display is turned off, but when the light source is turned on, There is a problem that 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, which may impair aesthetics.

Regarding this point, in the conventional top plate, the material constituting the inorganic pigment layer strongly absorbs the short wavelength side of visible light (violet and blue sides; high light energy), and the long wavelength side (red side; light However, since it weakly absorbs light (low as the energy of ), it has been a problem that it does not become achromatic black.

On the other hand, in the light absorption film 3 of the present embodiment, light absorption on the short wavelength side of visible light is absorbed by the bandgap of iron oxide and chromium oxide, and light absorption on the long wavelength side is performed by the free electrons of Ag. Therefore, even when the light is turned off, the top plate becomes achromatic black and has excellent aesthetics. In addition, the heat resistance can be improved while maintaining light absorption on the short wavelength side of visible light.

More specifically, the absorption coefficient α(λ) that depends on the wavelength of light is represented by the following formula (I).

α(λ)=α(λ) _{bandgap type} +α(λ) _{free electron type} =A·λ ⁻ⁿ +B·λ ² ≈C·λ ⁰ Formula (I)
(In formula (I), A, B and C are constants and n>0.)

That is, the absorption coefficient due to the bandgap of iron oxide, chromium oxide, etc., which absorbs light on the short wavelength side of visible light, is proportional to the n-th power of the inverse of the wavelength, and absorption by free electrons of Ag responsible for light absorption on the long wavelength side. Since the coefficient is proportional to the square of the wavelength, the absorption coefficient α(λ) of the light absorption film 3, which is represented by the sum of these coefficients, does not substantially depend on the wavelength and tends to be a constant value at any wavelength.

Thus, the film-coated transparent substrate 1 having the light-absorbing film 3 can uniformly absorb light particularly in almost the entire range of visible light. In addition, since the heat resistance is enhanced, it is possible to make it difficult for the optical properties to change due to heating, and it is possible to make it difficult for the change in color to occur. Therefore, the film-coated transparent substrate 1 can be 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 cookers and cover glasses for displays.

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, and preferably 65% by mass or less, more preferably 55% by mass or less. In this case, light can be absorbed more uniformly over substantially the entire visible light range. The content of Ag in the light absorption film 3 is the content of Ag with respect to the total metal element content excluding oxygen in the light absorption film 3 .

In the present invention, with respect to the content of metal elements excluding oxygen in the light absorbing film 3, the content of Fe in the light absorbing film 3 is preferably 25% by mass or more, more preferably 32% by mass or more. is 60% by mass or less, 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, and preferably 17% by mass or less, more preferably 12% by mass or less. The contents of Fe and Cr in the light absorption film 3 are the respective contents of Fe and Cr with respect to the total metal element contents excluding oxygen in the light absorption film 3 .

The light absorption film 3 may contain Ni, Mo, Cu, S, Mn, P, Si, and C, which are components contained in stainless steel. When the light absorbing film 3 contains Ni, its content is preferably 3% by mass or more, more preferably 6% by mass or more, and preferably 15% by mass or less, more preferably 12% by mass or less. be. The content of Ni in the light absorbing film 3 is the content of Ni with respect to the total metal element content excluding oxygen in the light absorbing film 3 . Moreover, the content of C in the light absorbing film 3 (whole) is preferably 1.2% by mass or less.

In the light absorbing film 3, the mass ratio of Cr to Fe (Cr/Fe) is preferably 0.10 or more, more preferably 0.20 or more, preferably 0.60 or less, and more preferably 0.40 or less. . In this case, it is possible to make it even more difficult for the color of the light absorbing film 3 to change due to heating.

The light absorbing film 3 may further contain Al. In this case, it is possible to make it even more difficult for the color of the light absorbing film 3 to change due to heating. The content of Al in the light absorbing film 3 is preferably 2.5% by mass or more, more preferably 5% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less. However, when considering the absorption coefficient of the film, the light absorption film 3 does not have to substantially contain Al. Note that "substantially free of Al" means that the content of Al in the light absorption film 3 is 0% by mass or more and 0.3% by mass or less. The content of Al in the light absorption film 3 is the content of Al with respect to the total content of metal elements excluding oxygen in the light absorption film 3 .

When the light absorbing film 3 further contains Al, it can be formed using a mixed target of Ag, stainless steel and Al. Alternatively, an Ag target, a stainless steel target, and an Al target may be used separately.

The content of Ag, Fe, Ni, Cr, Al, etc. in the light absorption film 3 can be determined, for example, by electron probe microanalyzer (EPMA), energy dispersive X-ray analysis, wavelength dispersive X-ray analysis, inductively coupled plasma It can be measured by mass spectrometry or the like, preferably by an electron probe microanalyzer (EPMA).

The thickness of the light absorption film 3 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, particularly preferably 20 nm or more, preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 1 μm or less. 500 nm or less, particularly preferably 100 nm or less. When the thickness of the light absorption film 3 is within the above range, the display of various information can be made more clearly visible when the light source is turned on, and the aesthetic appearance is further improved when the light source is turned off. can be done.

In the present invention, it is preferable that the light absorption film 3 has a matrix containing Fe, Cr, and O, and Ag is dispersed in the matrix. Particularly, in the light absorbing film 3, it is preferable that iron oxide and chromium oxide form a matrix, and Ag is dispersed in the matrix. In this case, the insulating property of the light absorbing film 3 can be further improved. Therefore, in this case, the film-coated transparent substrate 1 can be suitably used for a display having a touch panel function or a cooker top plate having a built-in display having a touch panel function. Part of Ag may exist as a matrix component as long as the insulation is maintained.

The average absorption coefficient of the light absorption film 3 at a wavelength of 400 nm to 700 nm is preferably 0.5 μm ⁻¹ or more, more preferably 10 μm ⁻¹ or more, preferably 80 μm ⁻¹ or less, and more preferably 70 μm ^{−1 or} less. When the average absorption coefficient is equal to or higher than the above 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, when the average absorption coefficient is equal to or less than the above upper limit, it is possible to more reliably and clearly see the display of various information when the light source is turned on. The absorption coefficient of the light absorbing film 3 can be derived from measurements of transmittance, reflectance, etc. by spectroscopic ellipsometry or a spectrophotometer. In that case, the measurement is performed from the light absorption film 3 side in a state of being laminated on the transparent substrate 2 .

In the light absorption 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, α1/α2 is 0.8 or more and 2.0. or less, and α3/α2 is preferably 0.8 or more and 2.0 or less. More preferably, 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, when the light source is turned off, the black color can be more achromatic, and the appearance can be further improved.

Further, in the light absorbing film 3, when the absorption coefficient at the wavelength λ is α _λ and the average absorption coefficient at the wavelength 400 nm to 700 nm is α _AVE , the absorption average deviation M given by the following formula (1) is 0.30. The following are preferable. In this case, when the light source is turned off, the black color can be more achromatic, and the appearance can be further improved.

If the Ag content in the light absorption film 3 is small, 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. There is On the other hand, when the content of Ag in the light absorption film 3 is large, the sheet resistance may easily decrease. In addition, α1/α2 may become too small, α3/α2 may become too large, and the average absorption deviation M may become too large.

The electrical resistance value (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, and still more preferably 10 ⁷ Ω ( 10 ⁷ Ω/□) or more. In this case, since the light absorbing film 3 is insulative, when it is used as a cover glass of an image display device or a top plate for a cooker, even if a touch panel is provided, the finger contact necessary for a capacitive touch sensor is not required. The change in capacitance due to is maintained, and the touch panel can be made to function. Note that the sheet resistance can be measured by a prescribed method such as ASTM D257, JIS K6271-1 (2015), JIS K6271-2 (2015), K6911 (1995).

In the present invention, when the film-coated transparent substrate 1 is heat treated at 500° C. for 1 hour, the absolute value of the amount of change in a ^* and b ^* in the L ^* a ^* b ^* color system of transmitted light before and after the heat treatment is , are each preferably 4 or less, more preferably 2 or less. In this case, it is possible to make it even more difficult for the color of the light absorbing film 3 to change due to heating.

L ^* in the L ^* a ^* b ^* color system of the film-coated transparent substrate 1 is, for example, 30 or more and 60 or less, a ^* is, for example, −5 or more and 5 or less, and b ^* is, for example, −5 or more. , 5 or less. Note that L ^* means "brightness index" (L axis = 0 to 100), a ^* and b ^* mean "chromatic neck index" (a axis = -60 to +60, b axis = -60 to +60). . Also, the L ^* a ^* b ^* values can be measured with a spectrophotometer from the light absorbing film 3 side of the transparent substrate 1 with film. As a spectrophotometer, for example, product number “U-4100” manufactured by Hitachi High-Tech Science Co., Ltd. can be used.

In the present invention, when the film-coated transparent substrate 1 is heat-treated at 500° C. for 1 hour, the absolute values of the amounts of change in x and y of transmitted light in the xyY color system before and after the heat treatment are each 0.010 or less. It is preferably 0.005 or less, more preferably 0.005 or less. In this case, it is possible to make it even more difficult for the color of the light absorbing film 3 to change due to heating.

In the xyY color system of the film-coated transparent substrate 1, x is, for example, 0.25 or more and 0.35 or less, y is, for example, 0.25 or more and 0.35 or less, and Y is, for example, 10 or more and 50. You can: The xyY values can be measured with a spectrophotometer from the light absorption film 3 side of the film-coated transparent substrate 1 . As a spectrophotometer, for example, product number “U-4100” manufactured by Hitachi High-Tech Science Co., Ltd. can be used.

The chroma C ^* _T of light transmitted through the film-coated transparent substrate 1 is preferably 7 or less, more preferably 2 or less, still more preferably 1 or less, particularly preferably 0.8 or less, and most preferably 0.5 or less. . In addition, the chroma C ^* _R of the reflected light from the film-coated transparent substrate 1 is preferably 7 or less, more preferably 2 or less, even more preferably 1 or less, particularly preferably 0.7 or less, and most preferably 0.5 or less. is. Here, the saturation C ^* is the saturation C ^* when irradiated with a D65 light source in the L ^* a ^* b ^* color system adopted in JIS Z 8781-4:2013. The chroma C ^* is obtained from the chromaticities a ^* and b ^* , and is expressed as C ^* =((a ^* ) ² +(b ^* ) ² ) ^1/2 . When the chroma C ^* is equal to or less than the above upper limit, the black color can be more achromatic when the light source is turned off, and the aesthetic appearance can be further improved.

From the viewpoint of further obscuring the boundary between the display area A and the non-display area B, which will be described later, the absolute value of the difference in the lightness (L ^* ) of the reflected light between the display area A and the non-display area B is preferably is 20 or less, more preferably 10 or less, and even more preferably 5 or less. Further, the absolute value of the difference in chroma (C ^* _R ) of reflected light between the display area A and the non-display area B is preferably 0.7 or less, more preferably 0.4 or less, and particularly preferably 0.3. It is below. The lightness (L ^* ) of the reflected light is measured from the light absorbing film 3 side of the film-coated transparent substrate 1 using, for example, a spectrophotometer (manufactured by Olympus, product number “USPM-RU-II”). can be done.

(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, the film-coated transparent substrate 21 further includes a dielectric multilayer film 26 on the light absorption film 3 . Other points are the same as in the first embodiment.

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 laminated in this order. In this embodiment, the number of laminated layers of the dielectric multilayer film 26 is five.

Examples of materials for the low refractive index film 27 include silicon oxide and aluminum oxide.

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.

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 , in the film-coated transparent substrate 31 , a dielectric multilayer film 36 including the light absorbing film 3 is provided on the first main surface 2 a of the transparent substrate 2 . Other points are the same as in the first embodiment.

In the dielectric multilayer film 36, low refractive index films 27 with a relatively low refractive index and light absorption films 3 as high refractive index films with a relatively high refractive index are alternately laminated in this order. In this embodiment, the number of laminated layers of the dielectric multilayer film 36 is five. The light absorption film 3 is the light absorption 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 layers of the light absorbing film 3 may be the high refractive index film 28 described in the second embodiment.

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 the film-coated transparent substrate 41 , a dielectric multilayer film 46 including the light absorbing film 3 is provided on the first main surface 2 a of the transparent substrate 2 . Other points are the same as in the first embodiment.

In the dielectric multilayer film 46, the high refractive index film 28 with a relatively high refractive index and the light absorption film 3 as a low refractive index film with a relatively low refractive index are alternately laminated in this order. Further, the outermost layer is provided with the low refractive index film 27 described in the second embodiment. When the low refractive index film 27 is provided as the outermost layer, the reflectance can be further reduced and the chemical durability can be further improved.

Further, in the present embodiment, the number of laminated layers of the dielectric multilayer film 46 is six. The light absorption film 3 is the light absorption film 3 described in the first embodiment, and the low refractive index film 27 and the high refractive index film 28 are the low refractive index film 27 and the high refractive index film 28 described in the second embodiment. This is the high refractive index film 28 . One of the two layers of the light absorption film 3 may be the low refractive index film 27 described in the second embodiment.

FIG. 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 FIG. 5, in the film-coated transparent substrate 51 , two layers of the light absorption film 3 are provided on the transparent substrate 2 . Dielectric multilayer films 56A and 56B are further provided between the transparent substrate 2 and the light absorbing film 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. Further, the outermost layer is provided with the low refractive index film 27 described in the second embodiment. Other points are the same as in the second embodiment.

Also in the second to fifth embodiments, the light absorbing film 3 contains Ag, Fe and Cr. Therefore, according to each film-coated transparent substrate, it is possible to clearly see the display of various information when the light source is turned on, and it is possible to make the display excellent in aesthetics when the light source is turned off. In particular, it is difficult for the color to change even when heated, and it is possible to stably provide excellent aesthetics when the light source is turned off.

Further, when a dielectric multilayer film is provided as in the second to fifth embodiments, for example, an antireflection function can be imparted. In this case, it is also possible to improve the contrast of the display.

At this time, the light absorption film 3 may be used as a high refractive index film as in the third embodiment, or the light absorption film 3 may be used as a low refractive index film as in the fourth embodiment. may The light absorption film 3 can be used as a low refractive index film or a high refractive index film by adjusting the magnitude of the refractive index according to the film formation conditions such as the mass ratio of Ag and iron oxide and the partial pressure of oxygen. can also In addition, the refractive index of the light absorption film 3 can be adjusted in the range of 1.2 or more and 2.0 or less, for example.

[Top plate for cooker]
FIG. 6 is a schematic cross-sectional view showing a cooker top plate according to one embodiment of the present invention. As shown in FIG. 6, a cooker top plate 61 includes a film-coated transparent substrate 1 .

In the cooker 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 cooking utensils such as pots and pans are placed. The back surface is the surface facing the light source 62 such as an LED or display and the heating device inside the cooker. Therefore, the cooking surface and the back surface have a relationship of front and back. In this embodiment, the transparent substrate 2 is made of low-expansion crystallized glass.

A light absorption film 3 is provided on the rear surface (first main surface 2a) of the transparent substrate 2 . A heat-resistant resin layer 63 is provided on the light absorption film 3 . Note that the heat-resistant resin layer 63 may be provided between the transparent substrate 2 and the light absorbing film 3 . In the present embodiment, the area where the heat-resistant resin layer 63 is not provided is the display area A in plan view. A non-display area B is a region where the heat-resistant resin layer 63 is provided in plan view.

The heat resistant resin layer 63 is a light blocking layer. Therefore, by providing the heat-resistant resin layer 63, the concealability of the internal structure of the cooker can be more reliably enhanced. The heat-resistant resin layer 63 can be composed of a heat-resistant resin such as silicone resin, a coloring pigment, and the like. Note that the heat-resistant resin layer 63 may not be provided.

A light source 62 such as a display or an LED is provided below the film-coated transparent substrate 1 . The light source 62 is a member provided for displaying information in the display area A. FIG. The information to be displayed in the display area A is not particularly limited. information.

In the display area A, the light from the light source 62 is transmitted through the light absorption film 3 and the transparent substrate 2 and emitted to the outside. Further, the light from the light source 62 is blocked by the heat-resistant resin layer 63 in the non-display area B. FIG. Therefore, in the display area A, letters, numerals, symbols, etc. can be displayed by allowing the light from the light source 62 to pass therethrough.

A cooker top plate 61 includes a transparent substrate 1 with a film. Therefore, when the light source 62 is turned on, the display of various information can be clearly seen, and when the light source 62 is turned off, the appearance can be excellent. In addition, the boundary between the display area A and the non-display area B can be made difficult to see while concealing the structure inside the cooker. Further, even when the cooker top plate 61 is heated at a high temperature during use, the color does not easily change. In addition, a display having a touch panel function may be built in the cooker.

[Cooker window glass]
Moreover, you may use the top plate 61 for cookers mentioned above as the window glass for heat cookers used for heat cookers, such as a microwave oven and an oven. In that case, the second main surface 2b of the transparent substrate 2 constituting the film-coated transparent substrate 1 described above is the main surface opposite to the heating device side in the heating cooker, and the transparent substrate constituting the film-coated transparent substrate 1 is used. The first main surface 2a of 2 can be used as the main surface on the heating device side of the heating cooker.

[cover glass]
FIG. 7 is a schematic cross-sectional view showing a cover glass according to one embodiment of the invention. As shown in FIG. 7, the cover glass 71 includes the film-coated transparent substrate 1 . The cover glass 71 is, for example, a cover glass arranged in front of the display.

In the cover glass 71, the first principal surface 2a of the transparent substrate 2 constituting the film-coated transparent substrate 1 is the principal surface arranged outside. On the other hand, the second main surface 2b of the transparent substrate 2 constituting the film-coated transparent substrate 1 is the display-side main surface. Therefore, in the cover glass 71, the light absorption film 3 is provided on the main surface 2a of the transparent substrate 2 opposite to the side on which the display is provided.

Since the cover glass 71 is also provided with the film-coated transparent substrate 1, the color does not easily change even when heated at a high temperature (for example, 300 ° C. to 400 ° C.) like a top plate for a cooker, and when the light source is turned off. Excellent aesthetics.

Hereinafter, the present invention will be described in further detail based on examples. However, the following examples are merely illustrative. The present invention is by no means limited to the following examples.

(Example 1)
In Example 1, a mixed target of Ag and stainless steel (SUS304) was used to form a light absorption film on a transparent glass substrate by a sputtering method. The Ag content in the mixed target was 32.6% by mass, and the stainless steel content was 67.4% by mass. At this time, the substrate temperature was set to 250° C., and the oxygen partial pressure was set to 0.03 Pa. Regarding the metal element contents excluding oxygen in the light absorbing film, the Ag content was 48.022% by mass, the Fe content was 32.782% by mass, and the Cr content was 10.615% by mass. Met. Also, the mass ratio of Cr to Fe (Cr/Fe) was 0.32. Also, the Ni content was 8.581% by mass. Each composition was measured by an electron probe microanalyzer (EPMA, manufactured by JEOL Ltd., product number "JXA-8100"). The optical properties of the obtained light absorption 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 a matrix in the obtained light-absorbing film, and Ag was dispersed in the matrix. Moreover, the obtained light absorbing film had an achromatic black color.

(Comparative example 1)
In Comparative Example 1, a mixed target of Ag and FeO was used to form a light absorption film on a transparent glass substrate by a sputtering method. The Ag content in the mixed target was 32.6% by mass, and the Fe content was 67.4% by mass. At this time, the substrate temperature was set to 250° C., and the oxygen partial pressure was set to 0.025 Pa. In addition, the Ag content was 58.1 mass % and the Fe content was 41.9 mass % in the metal element contents excluding oxygen in the light absorbing film. Each composition was measured by an electron probe microanalyzer (EPMA, manufactured by JEOL Ltd., product number "JXA-8100"). The optical properties of the obtained light absorption film were n (refractive index)=1.24 and k (extinction coefficient)=1.4 (wavelength 550 nm).

[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, α1/α2, α3/α2, An average absorption coefficient α _AVE and an absorption average deviation M were obtained. The results are shown in Table 1 below.

(Heat resistance test)
The film-coated transparent substrates obtained in Example 1 and Comparative Example 1 were subjected to heat treatment at temperatures of 200° C., 300° C., 400° C. and 500° C. for 1 hour, respectively. The transmission spectrum, a ^* and b ^* in the L ^* a ^* b ^* color system, x and y in the xyY color system, and sheet resistance were measured for the film-coated transparent substrates produced at each heat treatment temperature.

In addition, a ^* and b ^* in the L ^* a ^* b ^* color system of the transmission spectrum and transmitted light, and x and y in the xyY color system are measured by a spectrophotometer (manufactured by Hitachi High-Tech Science Co., Ltd., product number “U-4100 ”). The sheet resistance was measured by a DC two-probe method using platinum electrodes.

8 is a diagram showing the transmission spectrum of the film-coated transparent substrate after heat treatment in Example 1. FIG. 9 is a diagram showing a transmission spectrum of a film-coated transparent substrate after heat treatment in Comparative Example 1. FIG. 8 and 9 also show the transmission spectrum of the unheated film-coated transparent substrate.

From FIG. 8, it can be seen that the transparent substrate with the film of Example 1 has almost no change in the waveform of the transmission spectrum regardless of the heat treatment at any temperature. Also, it can be seen that the transmittance is almost constant in the wavelength range of 400 nm to 700 nm. On the other hand, it can be seen from FIG. 9 that the waveform of the transmission spectrum of the film-coated transparent substrate of Comparative Example 1 is greatly changed by the heat treatment.

10 is a diagram showing the relationship between the heat treatment temperature and the amount of change in a ^* and b ^* before and after the heat treatment in the film-coated transparent substrate of Example 1. FIG. FIG. 11 is a diagram showing the relationship between the heat treatment temperature and the amount of change in a ^* and b ^* before and after the heat treatment in the film-coated transparent substrate of Comparative Example 1. As shown in FIG.

As can be seen from FIG. 10, in the film-coated transparent substrate of Example 1, the amount of change in a ^* and b ^* before and after the heat treatment was 4 or less even at 500° C., showing almost no change in color. On the other hand, from FIG. 11, in the film-coated transparent substrate of Comparative Example 1, the amount of change in a ^* and b ^* in the L ^* a ^* b ^* color system before and after the heat treatment was greater than 4 at 500°C. was

FIG. 12 is a diagram showing the relationship between the heat treatment temperature of the film-coated transparent substrate of Example 1 and the amount of change in x and y before and after the heat treatment. FIG. 13 is a diagram showing the relationship between the heat treatment temperature and the amount of change in x and y before and after the heat treatment in the film-coated transparent substrate of Comparative Example 1. As shown in FIG.

As shown in FIG. 12, in the film-coated transparent substrate of Example 1, the amount of change in x and y before and after the heat treatment was 0.01 or less even at 500° C., and there was almost no change in color. On the other hand, from FIG. 13, in the film-coated transparent substrate of Comparative Example 1, the amount of change in x and y before and after the heat treatment was greater than 0.01 at 500.degree.

From these results, it was confirmed that the film-coated transparent substrate of Example 1 was less likely to change color due to heating, and was excellent in appearance even when the light source was turned off.

Table 2 below shows the measurement results of the sheet resistance (resistance value) of the film-coated transparent substrate of Example 1 at each heat treatment temperature.

From Table 2, it was confirmed that the film-coated transparent substrate of Example 1 had high insulating properties when heat-treated at any temperature.

Reference Signs List 1, 21, 31, 41, 51... Transparent substrate with film 2... Transparent substrate 2a... First main surface 2b... Second main surface 3... Light absorbing films 26, 36, 46, 56A, 56B... Dielectric multilayer Film 27 Low refractive index film 28 High refractive index film 61 Top plate for cooker 62 Light source 63 Heat resistant resin layer 71 Cover glass

Claims (15)

a transparent substrate;
a light absorbing film provided on one main surface of the transparent substrate;
with
A film-coated transparent substrate, wherein the light-absorbing film contains Ag, Fe, and Cr. 2. The film-coated transparent substrate according to claim 1, wherein said light absorbing film further contains O. The film-coated transparent substrate according to claim 1 or 2, wherein the mass ratio of Cr to Fe (Cr/Fe) is 0.10 or more and 0.60 or less. 4. The film-coated transparent substrate according to claim 1, wherein the light-absorbing film has a matrix containing Fe, Cr, and O, and the Ag is dispersed in the matrix. 5. The film-coated transparent substrate according to claim 1, wherein the light absorption film has an average absorption coefficient of 0.5 μm ⁻¹ or more and 80 μm ⁻¹ or less at a wavelength of 400 nm to 700 nm. In the light absorption film, α1/α2 is 0.8 or more and 2.0 or less, where α1 is an absorption coefficient at a wavelength of 436 nm, α2 is an absorption coefficient at a wavelength of 546 nm, and α3 is an absorption coefficient at a wavelength of 700 nm. The film-coated transparent substrate according to any one of claims 1 to 5, wherein α3/α2 is 0.8 or more and 2.0 or less. 7. The film-coated transparent substrate according to claim 6, wherein in the light absorption 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. . In the light-absorbing film, when the absorption coefficient at a wavelength λ is α _λ and the average absorption coefficient at a wavelength of 400 nm to 700 nm is α _AVE , the absorption average deviation M represented by the following formula (1) is 0.30 or less. The film-coated transparent substrate according to any one of claims 1 to 7.

9. The film-coated transparent substrate according to claim 1, further comprising a dielectric multilayer film on the light absorption film. 9. The film-coated transparent substrate according to claim 1, comprising a dielectric multilayer film provided on the transparent substrate and including the light absorbing film. 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 laminated,
11. The film-coated transparent substrate according to claim 10, wherein at least one layer of said high refractive index film is said light absorbing film. 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 laminated,
11. The film-coated transparent substrate according to claim 10, wherein at least one layer of said low refractive index film is said light absorbing film. A film-coated transparent substrate according to any one of claims 1 to 12,
The transparent substrate has a cooking surface on which the cooking utensil is placed and a back surface opposite to the cooking surface,
A top plate for a cooker, wherein the light absorbing film is arranged on the back surface of the transparent substrate. A window glass used in a heating cooker,
A film-coated transparent substrate according to any one of claims 1 to 12,
A window glass for a heating cooker, wherein the light absorption film is arranged on the main surface of the transparent substrate on the heating device side of the heating cooker. A cover glass used for a display,
A film-coated transparent substrate according to any one of claims 1 to 12,
A cover glass, wherein the light absorption film is arranged on the main surface of the transparent substrate opposite to the side on which the display is provided.

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