JP5182102B2 - Cooker top plate - Google Patents

Description

  The present invention relates to a top plate for a cooker disposed on top of an electromagnetic heating (IH) cooker, an infrared heating cooker, a gas cooker, or the like.

  As a top plate for a cooker used in an electromagnetic heating (IH: Induction Heating) cooker or an infrared heating cooker, a glass substrate or a ceramic substrate having a low thermal expansion is used. Moreover, since the gas cooker is excellent in aesthetics and cleanability, a low thermal expansion glass substrate, ceramic substrate, or the like is used.

  The top plate for a cooker using these low thermal expansion substrates is required to have a low light transmittance in the visible light range in order to visually conceal parts such as a temperature sensor arranged inside the cooker. It has been. As a cooker top plate having a low light transmittance in the visible light region, a cooker top plate having a light shielding layer formed on a glass substrate is known. As an example thereof, for example, Patent Document 1 below discloses a top plate for a cooker in which a light-shielding film made of Si, Ti, or a nitride thereof is formed on a glass substrate. In the cooker top plate described in Patent Document 1, by changing the material of the light-shielding film, it is possible to color various colors while keeping the light transmittance in the visible light region low. For this reason, by using the technique described in Patent Document 1, it is possible to provide a top plate for a cooker having various colors and excellent aesthetics.

JP 2004-333102 A

  However, the top plate for a cooker described in Patent Document 1 has a high light reflectance in the visible light region, so the reflected light in the light shielding film is strong, and it is impossible to realize a calm color with reduced brightness. There's a problem.

  An object of the present invention is to provide a top plate for a cooker that can visually hide parts such as a temperature sensor disposed inside the cooker, that has a reflected light suppressed, and has a shade with reduced brightness. Is to provide.

  The cooker top plate according to the present invention is a cooker top plate disposed above the cooker, and is formed on a glass substrate and one surface of the glass substrate, and is made of silicon nitride or aluminum nitride. A first interference layer; a second interference layer made of silicon; and a light-shielding layer made of a metal film, formed on the second interference layer. The protective layer is formed on the light shielding layer and includes at least one protective layer selected from silicon nitride, zirconium nitride, titanium nitride, tantalum nitride, tungsten nitride, and niobium nitride.

  In the present invention, the first interference layer, the second interference layer, the light shielding layer, and the protective layer are laminated in this order on the glass substrate, and the second interference layer is made of silicon. For this reason, a low light transmittance in the visible light region is realized. Therefore, by using the cooker top plate of the present invention, a temperature sensor or the like disposed inside the cooker can be visually hidden. . At the same time, in the present invention, a low light reflectance in the visible light region is also realized, and therefore, it is possible to color in a shade with reduced brightness.

In the present invention, the glass substrate is preferably a glass substrate having a small thermal expansion coefficient and high thermal shock resistance that can withstand rapid cooling from 600 ° C. Specifically, the glass substrate is more preferably a glass substrate having an average thermal expansion coefficient of 30 × 10 ⁻⁷ / ° C. or less at 30 to 500 ° C., and an average thermal expansion at 30 to 500 ° C. More preferably, the glass substrate has a coefficient of −10 × 10 ⁻⁷ to + 30 × 10 ⁻⁷ / ° C., and the average thermal expansion coefficient at 30 to 500 ° C. is −10 × 10 ⁻⁷ to + 20 × 10 ⁻⁷ / A glass substrate having a temperature of ° C is particularly preferred. Specific examples of such a low thermal expansion glass substrate include a low thermal expansion borosilicate glass substrate, a quartz glass substrate, or a low expansion crystallized glass substrate having a β-quartz solid solution as a main crystal.

  The first interference layer is a layer made of silicon nitride or aluminum nitride. This is because the heat resistance and impact resistance of the cooker top plate can be increased by forming the first interference layer from silicon nitride or aluminum nitride.

  The thickness of the first interference layer correlates with the color tone of the cooker top plate, and the color tone of the cooker top plate can be changed by changing the thickness of the first interference layer. Specifically, by reducing the thickness of the first interference layer, the color tone of the cooker top plate can be shifted to the blue side. On the other hand, when the thickness of the first interference layer is increased, the color tone of the cooker top plate is shifted to the red side.

  The thickness of the first interference layer can be appropriately set according to the color tone to be colored, but generally it is preferably in the range of 5 to 250 nm. If the thickness of the first interference layer becomes too thin, it becomes difficult to obtain an interference effect between the glass substrate and the first interference layer or between the second interference layer and the first interference layer. In some cases, the top plate cannot be colored in various colors. On the other hand, if the thickness of the first interference layer becomes too thick, the technical effect associated therewith may not be obtained, which may be economically disadvantageous. When the first interference layer is formed of silicon nitride, the thickness of the first interference layer is more preferably in the range of 50 to 250 nm. When the first interference layer is formed from aluminum nitride, the thickness of the first interference layer is more preferably in the range of 5 to 50 nm.

  A 2nd interference layer is a layer which consists of silicon, and has the function to reduce the light transmittance and light reflectance in the visible light region of the top plate for cookers. Further, by providing the second interference layer, it is possible to increase the degree of coloring of the cooker top plate. That is, it becomes possible to color the cooker top plate in a darker color.

  The thickness of the second interference layer is preferably in the range of 1 to 100 nm, and more preferably in the range of 5 to 70 nm. If the thickness of the second interference layer is too thin, it tends to be difficult to sufficiently reduce the light transmittance and light reflectance in the visible light region of the cooking utensil top plate. On the other hand, when the thickness of the second interference layer becomes too thick, the light transmittance in the visible light region of the top plate for a cooker tends to be too small. If the light transmittance in the visible light region of the cooking device top plate becomes too small, the visibility of the light source for display is reduced when used in an electromagnetic heating (IH) cooking device in which a light source for display is arranged below the top plate. Tend to.

  The thickness of the second interference layer is also correlated with the color tone of the cooker top plate, and the color tone of the cooker top plate can be changed by changing the thickness of the second interference layer.

  The light shielding layer is made of a metal film and has a function of reducing the light transmittance in the visible light region of the top plate for a cooker. The light shielding layer is preferably made of titanium or niobium. Good heat resistance can be obtained by forming the light shielding layer from titanium or niobium.

  The thickness of the light shielding layer is preferably in the range of 75 to 150 nm. If the film thickness of the light shielding layer becomes too thin, the internal structure of the cooking device is likely to be visually recognized, and the aesthetic appearance may be impaired. Further, if the thickness of the light shielding layer becomes too thick, the technical effect associated therewith may not be obtained, which may be disadvantageous economically.

  The protective layer is made of at least one nitride thin film selected from silicon nitride, zirconium nitride, titanium nitride, tantalum nitride, tungsten nitride, and niobium nitride. By forming the protective layer from such a nitride thin film, good heat resistance can be obtained.

  The thickness of the protective layer is preferably in the range of 50 to 200 nm. If the protective layer is too thin, good heat resistance may not be obtained. Moreover, even if the protective layer becomes too thick, the technical effect associated therewith may not be obtained, which may be disadvantageous economically.

  In the present invention, it is preferable that a third interference layer made of silicon nitride or aluminum nitride is further provided between the second interference layer and the light shielding layer. When this third interference layer is provided, the color tone of the top plate for the cooker can be adjusted by adjusting the thicknesses of the three layers of the first to third interference layers. It can be adjusted freely. Further, by providing the third interference layer, it is possible to increase the contrast and further diversify the color tone of the cooker top plate. Specifically, for example, it becomes easier to produce a metallic color tone.

  In addition, by providing the third interference layer, the heat resistance of the cooker top plate can be improved. The reason is not clear, but is because the light-shielding layer made of the metal film and the second interference layer made of silicon are isolated by the third interference layer, and the reaction between the metal film and silicon can be suppressed. it is conceivable that.

  Similar to the thickness of the first interference layer, the thickness of the third interference layer is also correlated with the color tone of the top plate for a cooker. By changing the thickness of the third interference layer, the color tone of the cooker top plate can be changed. Specifically, by reducing the thickness of the third interference layer, the color tone of the cooker top plate can be shifted to the blue side. On the other hand, when the thickness of the third interference layer is increased, the color tone of the cooker top plate is shifted to the red side.

  The thickness of the third interference layer can be appropriately set depending on the color tone to be colored, but generally it is preferably in the range of 15 nm to 150 nm. If the thickness of the third interference layer becomes too thin, it becomes difficult to obtain an interference effect between the third interference layer, the first interference layer, and the second interference layer. May not be able to be colored. Moreover, it exists in the tendency for the heat resistance of the top plate for cookers to fall. On the other hand, if the thickness of the third interference layer becomes too thick, the technical effect associated therewith may not be obtained, which may be economically disadvantageous. Whether the third interference layer is formed from silicon nitride or the third interference layer is formed from aluminum nitride, the thickness of the third interference layer is in the range of 20 to 100 nm. More preferably it is.

  Note that the third interference layer may be formed of the same material as the first interference layer, or may be formed of a material different from that of the first interference layer.

  In the present invention, each of the first to third interference layers, the light shielding layer, and the protective layer may be provided as a single layer or a plurality of layers.

In the present invention, a method for forming each layer constituting the top plate for a cooker is not particularly limited, but the first to third interference layers and the protective layer are formed by physical vapor deposition such as sputtering, vacuum vapor deposition, and ion plating. A thin film formed by a method in a gas atmosphere having a N ₂ gas content of 90 to 100% by volume is preferred. Thus, by using a thin film in which the content of N ₂ gas is formed in a gas atmosphere from 90 to 100% by volume as the third interference layer and the protective layer of, having better heat resistance It can be a top plate for a cooker.

Details of the reason why good heat resistance can be obtained by forming the first to third interference layers and the protective layer in a gas atmosphere in which the content of N ₂ gas is 90 to 100% by volume are not clear. Although a dense nitride thin film can be formed by forming the first to third interference layers and the protective layer in a gas atmosphere in which the content of N ₂ gas is 90 to 100% by volume, It seems that even in the heat resistance test, the film thickness changes little so that it shows good heat resistance. In addition, in this invention, heat resistance means that there is little change of a color tone by a heat resistance test.

In each of the formation steps of the first to third interference layers and the protective layer, if the content of N ₂ gas in the gas atmosphere when forming each layer is too small, good heat resistance cannot be obtained. A more preferable range of the N ₂ gas is 95 to 100% by volume, and more preferably 97.5 to 100% by volume.

The first to third interference layers and the protective layer are preferably formed by a sputtering method among the above forming methods. Conventionally, when a nitride thin film is formed by a physical vapor deposition method such as a sputtering method, a mixed gas in which an inert gas such as an Ar (argon) gas is mixed with an N ₂ gas is used as an atmospheric gas. However, if the first to third interference layers and the protective layer are formed in a conventional gas atmosphere containing a large amount of an inert gas such as Ar gas, it is difficult to obtain sufficiently good heat resistance. By setting the content of N ₂ gas to 90 to 100% by volume, a top plate for a cooker that is particularly excellent in heat resistance can be obtained.

  In the cooker top plate of the present invention, since the second interference layer made of silicon is provided between the first interference layer made of silicon nitride or aluminum nitride and the light shielding layer made of a metal film, the visible light region A low light transmittance and a low light reflectance are realized. Therefore, the temperature sensor etc. which are arrange | positioned inside the cooking appliance can be concealed visually, and it can be made to color with the calm hue which reduced the brightness.

It is sectional drawing of the top plate for cookers of Example 1. FIG. It is a graph showing the relationship between the luminous reflectance in Examples 1-5 and Comparative Examples 1-3 and luminous transmittance. In FIG. 2, the vertical axis representing luminous transmittance is a logarithmic axis.

  EXAMPLES Hereinafter, although this invention is demonstrated based on a specific Example, this invention is not limited to a following example.

Example 1
[Production of top plate for cooker]
FIG. 1 shows a cross-sectional view of the top plate for a cooking device of this embodiment. In the present example, the cooker top plate 1 shown in FIG. 1 was produced. As the glass substrate 2, a crystallized glass substrate (“Neoceram N-0” manufactured by Nippon Electric Glass Co., Ltd .: average linear thermal expansion coefficient at 30 ° C. to 500 ° C .: 0 × 10 ⁻⁷ / ° C., thickness 4 mm) was used. On this glass substrate 2, the film materials shown in Table 1 are used, and the first to third interference layers 3 to 5, the light shielding layer 6 and the protective layer 7 are arranged in this order so as to have the thickness shown in Table 1. Each was formed by sputtering.

[Color tone observation]
About each obtained top plate 1 for cookers, the color tone was observed visually. The observation results are shown in Table 1.

(Measurement of luminous reflectance and luminous transmittance)
About each obtained top plate 1 for cookers, the luminous reflectance and luminous transmittance were measured according to the method shown next. Luminous reflectance (tristimulus value Y ₁₀ ) is described in “JIS Z 8701: 1999 5.2.1 Tristimulus value of object color by reflection” using reflectance at each wavelength in the wavelength range of 380 nm to 780 nm. It calculated according to the formula (2).

Further, the luminous transmittance (tristimulus value Y ₁₀ ) is “JIS Z 8701: 1999 5.2.2 Tristimulus value of object color by transmission” using the transmittance at each wavelength in the wavelength range of 380 nm to 780 nm. It calculated according to the formula (3) described in 1.

Incidentally, the reflectance and transmittance at each wavelength in the wavelength range of 380~780nm used for calculating the luminous reflectance (tristimulus value _{Y 10)} and luminous transmittance (tristimulus values _{Y 10),} Hitachi Measurement was performed using a spectrophotometer U-4000 manufactured by High Technologies.

In the above calculation, the color matching function in the X ₁₀ Y ₁₀ Z ₁₀ color system is used as the color matching function.

(Example 2)
Except that the thickness of the second interference layer 4 was 5 nm, a top plate for a cooker was prepared in the same manner as in Example 1 above, and color tone observation, luminous reflectance and luminous transmittance were measured.

(Example 3)
A top plate for a cooker was prepared in the same manner as in Example 1 except that the thickness of the first interference layer 3 was 50 nm and the thickness of the second interference layer 4 was 45 nm, and color tone observation and luminous reflectance were performed. The luminous transmittance was measured.

Example 4
Except that the thickness of the second interference layer 4 was set to 65 nm, a top plate for a cooker was prepared in the same manner as in Example 3, and color tone observation, luminous reflectance, and luminous transmittance were measured.

(Example 5)
A top plate for a cooker was prepared in the same manner as in Example 1 except that the third interference layer 5 was not provided and the light shielding layer 6 was a niobium film having a thickness of 100 nm, and color tone observation, luminous reflectance, and visual acuity were observed. The transmittance was measured.

(Comparative Example 1)
A silicon nitride film having a thickness of 500 nm, a silicon film having a thickness of 50 nm, and a silicon nitride film having a thickness of 500 nm are formed in this order by sputtering on the same substrate as the crystallized glass substrate used in Example 1. Thus, a cooker top plate according to Comparative Example 1 was produced. About the obtained cooker top plate, color tone observation and luminous reflectance and luminous transmittance were measured in the same procedure as in Example 1 above.

(Comparative Example 2)
A silicon nitride film having a thickness of 150 nm, a titanium film having a thickness of 200 nm, and a silicon nitride film having a thickness of 150 nm are formed in this order by sputtering on the same substrate as the crystallized glass substrate used in Example 1. Thus, a cooker top plate according to Comparative Example 2 was produced. About the obtained cooker top plate, color tone observation and luminous reflectance and luminous transmittance were measured in the same procedure as in Example 1 above.

(Comparative Example 3)
A silicon nitride film having a thickness of 20 nm, a titanium film having a thickness of 20 nm, a silicon film having a thickness of 200 nm, and a silicon nitride film having a thickness of 150 nm are formed on the same substrate as the crystallized glass substrate used in Example 1. A top plate for a cooker according to Comparative Example 3 was produced by forming each layer in this order by sputtering. About the obtained cooker top plate, color tone observation and luminous reflectance and luminous transmittance were measured in the same procedure as in Example 1 above.

  Table 1 below shows the results of color tone observation, luminous reflectance, and luminous transmittance measurement in Examples 1 to 5 and Comparative Examples 1 to 3. FIG. 2 shows the relationship between luminous reflectance and luminous transmittance in Examples 1 to 5 and Comparative Examples 1 to 3.

  As shown in Table 1 and FIG. 2, in Examples 1 to 5 in which the first interference layer 3, the second interference layer 4, and the light shielding layer 6 are formed in this order, the luminous reflectance and Both luminous transmittances were low. On the other hand, in Comparative Example 1 in which the light shielding layer 6 was not provided, the luminous transmittance was large although the luminous reflectance was small. Further, in Comparative Example 2 in which the second interference layer 4 was not provided, the luminous reflectance was large although the luminous transmittance was small. Further, in Comparative Example 3 in which the first interference layer, the light shielding layer, and the silicon film were formed in this order, both the luminous transmittance and the luminous reflectance were increased. From this result, in addition to the first interference layer 3 made of silicon nitride or aluminum nitride and the light shielding layer 6 made of a metal film, the second light shielding layer 4 made of silicon is changed into the first interference layer 3 and the light shielding layer 6. , The luminous reflectance and luminous transmittance can both be reduced, so that the components placed inside the cooker can be visually shielded and the brightness has been reduced. It can be seen that a calm color can be realized.

  Moreover, it turns out that the color tone of the top plate for cookers can be changed by changing the thickness of the 1st-3rd interference layers 3-5 from the comparison of Examples 1-4. Specifically, when the thickness of the first to third interference layers 3 to 5 is thin, a blue color tone is obtained, and when the thickness of the first to third interference layers 3 to 5 is thick, the red side is obtained. It can be seen that the color tone is obtained.

DESCRIPTION OF SYMBOLS 1 ... Top plate 2 for cooker ... Glass substrate 3 ... 1st interference layer 4 ... 2nd interference layer 5 ... 3rd interference layer 6 ... Light-shielding layer 7 ... Protective layer

Claims (7)

A top plate for a cooker disposed above the cooker,
A glass substrate;
A first interference layer formed on one surface of the glass substrate and made of silicon nitride or aluminum nitride;
A second interference layer formed on the first interference layer and made of silicon;
A light-shielding layer formed on the second interference layer and made of a metal film;
A protective layer formed on the light shielding layer and made of at least one selected from silicon nitride, zirconium nitride, titanium nitride, tantalum nitride, tungsten nitride, and niobium nitride ;
A third interference layer disposed between the second interference layer and the light shielding layer and made of silicon nitride or aluminum nitride;
A top plate for a cooking device, comprising: The cooktop top plate according to claim 1 , wherein the thickness of the third interference layer is in the range of 15 to 150 nm. The top plate for a cooker according to claim 1 or 2 , wherein the thickness of the first interference layer is in the range of 5 to 250 nm. The thickness of the said 2nd interference layer exists in the range of 1-100 nm, The top plate for cookers of any one of Claims 1-3 characterized by the above-mentioned. The top plate for a cooking appliance according to any one of claims 1 to 4 , wherein the light shielding layer is made of titanium or niobium. The thickness of the said light shielding layer exists in the range of 75-150 nm, The top plate for cookers of any one of Claims 1-5 characterized by the above-mentioned. The thickness of the said protective layer exists in the range of 50-200 nm, The top plate for cookers of any one of Claims 1-6 characterized by the above-mentioned.

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