Plate for cooking apparatus and cooking apparatus including same

Abstract

A plate for a cooking apparatus according to one embodiment of the present invention comprises: a glass ceramic substrate; and a hard coating layer disposed on the glass ceramic substrate and including a plurality of calcium aggregation structures in at least a partial area, wherein in the hard coating layer, a ratio of the calcium aggregation structures per unit volume increases as the distance from the upper surface of the glass ceramic substrate decreases on a cross section perpendicular to the upper surface of the glass ceramic substrate.

Description

Plate for cooking appliance and cooking appliance including same

[0001] The present invention relates to a plate for a cooking appliance and a cooking appliance including the same, and more particularly, to a cooking appliance used to heat food by generating heat and a plate for a cooking appliance applied thereto.

[0002] Induction devices (induction heating devices) are used as devices that generate heat and heat food. In particular, cooktops (or hobs) are used as cooking appliances that heat food using induction devices.

[0003] Typically, ceramic glass, with its excellent heat resistance, is used on the top of cooktops. Ceramic glass rarely fractures under thermal shock and boasts excellent mechanical strength and thermal conductivity. However, when applied to cooktops, ceramic glass is continuously exposed to high temperatures and physical impacts, requiring even greater properties like mechanical strength and heat resistance. Therefore, research is being conducted into utilizing various coating layers to improve these properties.

[0004] According to one embodiment of the present invention, the purpose is to provide a cooking plate with improved scratch resistance and a variety of colors, and a cooking appliance including the same, thereby improving aesthetics and functionality. In particular, when the cooking appliance is white, the purpose is to provide a cooking plate that embodies the vividness of the white color while ensuring excellent mechanical strength.

[0005] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0006] According to one embodiment of the present invention, a plate for a cooking appliance includes a glass ceramic substrate and a hard coating layer disposed on the glass ceramic substrate and including a plurality of calcium aggregate structures in at least a portion of the hard coating layer, wherein the ratio of the calcium aggregate structures per unit area of ​​the hard coating layer increases as it approaches the upper surface of the glass ceramic substrate on a cross-section perpendicular to the upper surface of the glass ceramic substrate.

[0007] In addition, a plate for a cooking appliance according to an embodiment of the present invention comprises a glass ceramic substrate having a beta-spodumene crystal phase, a hard coating layer including a plurality of calcium aggregate structures distributed at least in an area adjacent to the glass ceramic substrate (210) and an encapsulating layer disposed on the hard coating layer and covering the hard coating layer, and has an L* value of 80 or more and 100 or less in the CIE Lab* color space.

[0008] In addition, a cooking appliance according to one embodiment of the present invention includes a cooking appliance plate on which a cooking vessel is placed, and a body including a plurality of induction heating coils arranged at a lower portion of the cooking appliance plate and configured to generate a magnetic field, wherein the cooking appliance plate includes a glass ceramic substrate, and a colorless transparent hard coating layer arranged on the glass ceramic substrate, and the hard coating layer includes a plurality of calcium aggregate structures each having a diameter of 40 nm or more and 60 nm or less.

[0009] According to an embodiment of the present invention, a cooking plate capable of being realized in a variety of colors can be provided. In particular, when implementing a white cooking plate, excellent scratch resistance can be secured even when a colorless transparent hard coating layer is applied.

[0010] Figure 1 is a perspective view of an entire cooking appliance according to one embodiment of the present invention.

[0011] Figure 2 is an exploded perspective view of the cooking appliance illustrated in Figure 1.

[0012] Figure 3 is a cross-sectional view taken along line A-A' shown in Figure 2.

[0013] Figure 4 is an enlarged cross-sectional view of area B shown in Figure 3.

[0014] Figure 5a shows the calcium distribution in area B of a conventional top plate.

[0015] Figure 5b is a diagram illustrating the calcium distribution in area B of the upper plate according to an embodiment of the present invention.

[0016] Figure 6a is a drawing showing a test of the scratch resistance of the top plate.

[0017] Figure 6b is a photograph of the surface of the top plate before performing the scratch resistance test.

[0018] Figure 7a is an exemplary photograph of the surface of the upper plate after the scratch resistance test has been completed.

[0019] Figures 7b and 7c are comparative examples of photographs taken of the surface of the top plate after the scratch resistance test has been completed.

[0020] Figure 8a is an exemplary photograph of the surface of the top plate after the scratch resistance test has been completed.

[0021] Figure 8b is a comparative example photograph of the surface of the top plate after the scratch resistance test has been completed.

[0022] FIG. 9 is a cross-sectional view taken along line A-A' of a top plate according to another embodiment of the present invention.

[0023] Fig. 10 is a cross-sectional view taken along line A-A' of a top plate according to another embodiment of the present invention.

[0024] Figure 11a is a table showing the composition and composition ratio of a glass ceramic substrate according to an embodiment of the present invention.

[0025] Figure 11b is a table showing the composition and composition ratio of a hard coating layer according to an embodiment of the present invention.

[0026] Figure 11c is a table showing the composition and composition ratio of a sealing layer according to an embodiment of the present invention.

[0027] Figure 12 is a table showing the values ​​measured for nanoindentation of a top plate according to an embodiment of the present invention.

[0028] Figure 13 is a photograph of a Mohs hardness tester for measuring Mohs hardness.

[0029] It should be understood that the various embodiments of the present disclosure and the terminology used therein are not intended to limit the technical features described in the present disclosure to specific embodiments, but include various modifications, equivalents, or substitutes of the embodiments.

[0030] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0031] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0032] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0033] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0034] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0035] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0036] Terms such as "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0037] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0038] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0039] Hereinafter, a cooking plate according to an embodiment of the present invention and a cooking appliance including the same will be described.

[0040] FIG. 1 is a perspective view of a cooking appliance according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the cooking appliance illustrated in FIG. 1.

[0041] Referring to FIGS. 1 and 2, a cooking appliance (1000) according to an embodiment of the present invention may be an induction heating device (induction device) that heats and cooks food using the principle of induction heating. The cooking appliance (1000) transfers heat to a cooking vessel (CT) mounted on the cooking appliance (1000) using the principle of induction heating. However, the present invention does not specifically limit the heating principle of the cooking appliance (1000).

[0042] According to the present embodiment, a user interface (UI) may be provided in a portion of the area defined by the upper surface of the cooking appliance (1000). The user interface (UI) may include a power input unit (PW), a display unit (DP), and a control unit (CR). A user may input power through the power input unit (PW) and control the cooking appliance (1000) through the control unit (CR). In addition, the user may check cooking information, including the temperature of the cooking container (CT), the elapsed cooking time, and / or the date / time, through the display unit (DP).

[0043] A cooking appliance (1000) includes a main body (100) and a cooking appliance plate (hereinafter, top plate) (200). The main body (100) can be detachably coupled to a top plate (200) positioned on the upper portion of the main body.

[0044] The main body (100) includes a housing (110), a plurality of induction heating coils (121, 122, 123), a coil mounting plate (130), an interface board (140), and a driving circuit board (not shown).

[0045] The housing (110) forms the exterior of the cooking appliance (1000). The housing (110) can accommodate components of the main body (100) in the internal space defined by the housing (110). In addition, the housing (110) can support a top plate (200) disposed on the upper portion of the housing (110). The housing (110) may have a box shape with an open upper portion. In the present embodiment, the housing (110) has a rectangular shape in which the upper surface has a short side in a first direction (DR1) and a long side in a second direction (DR2) orthogonal to the first direction (DR1). However, in the present invention, the specific shape of the housing (110) is not particularly limited.

[0046] Induction heating coils (121, 122, 123) are housed inside the housing (110). The area where the induction heating coils (121, 122, 123) are placed defines a heating area. That is, a user can inductively heat food inside the cooking tool (CT) by placing the cooking tool (CT) on an area on the top surface of the cooking appliance (1000) corresponding to the area where the induction heating coils (121, 122, 123) are placed. The induction heating coils (121, 122, 123) have a shape that is wound in a roughly circular shape so as to form a magnetic field in a vertical direction (DR3) when current is applied. The induction heating coils (121, 122, 123) can be electrically connected to a driving circuit board (not shown) to receive a driving signal.

[0047] Induction heating coils (121, 122, 123) can be mounted on a coil mounting plate (130). Guide holes for mounting the induction heating coils (121, 122, 123) on the coil mounting plate (130) can be formed.

[0048] In this embodiment, the case where induction heating coils (121, 122, 123) are applied as a heat source has been described, but the present invention is not limited thereto. For example, according to another embodiment of the present invention, in addition to the induction heating coils (121, 122, 123), an induction heater using an induction heating method or a radiant heater using an electric resistance method may be applied as a heat source.

[0049] The interface board (140) is arranged inside the housing (110) to correspond to the user interface (IU) of the cooking appliance (1000). Specifically, the interface board (140) may include a display panel (141), a power input terminal (142a), and touch input terminals (142b, 142c). The display panel (141) is arranged in an area corresponding to the display unit (DP). The power input terminal (142a) is arranged in an area corresponding to the power input unit (PW), and the touch input terminals (142b, 142c) are arranged in an area corresponding to the operation unit (CR). In the present embodiment, the power input terminal (142a) and the touch input terminals (142b, 142c) may be touch electrodes that receive touch signals.

[0050] A driving circuit board (not shown) is placed inside the housing (110) to control the operation of the induction heating coils (121, 122, 123) and the interface board (140). In an embodiment of the present invention, the driving circuit board (not shown) may be placed on the back surface of the coil mounting plate (130). However, the present invention is not particularly limited to the position of the driving circuit board (not shown).

[0051] The top plate (200) is placed on the upper part of the main body (100). An indicator window (201) and a plurality of guide marks (PPa, PPb, PPc, 202a, 202b, 202c) may be formed on the upper surface of the top plate (200).

[0052] The display window (201) is provided to expose the display panel (141) to the outside, and the area of ​​the upper plate (200) where the display window (201) is formed may have light transmittance.

[0053] A plurality of guide marks (PPa, PPb, PPc, 202a, 202b, 202c) can be printed on the upper surface of the upper plate through superimposed printing. For example, a plurality of guide marks (PPa, PPb, PPc, 202a, 202b, 202c) can be formed by printing a pattern with superimposed ink on the upper surface of the upper plate (200) and then heating the pattern at a predetermined temperature so that the superimposed ink permeates into the upper plate (200). In the present invention, any material used for superimposed printing can be used without particular limitation as long as it is a component generally known as superimposed ink.

[0054] The plurality of guide marks (PPa, PPb, PPc, 202a, 202b, 202c) may include a heating area marking mark (PPa, PPb, PPc) indicating a heating area, a power marking mark (202a) indicating a power supply (PW), and a controller mark (202b, 202c) indicating a control unit (CR). In the present embodiment, the top plate (200) may have a characteristic capable of transmitting an external touch signal to a power input terminal (142a) and a touch input terminal (142b, 142c).

[0055] Although not shown in the drawing, the cooking appliance (1000) according to an embodiment of the present invention may further include other components in addition to the main body (100) and the top plate (200). For example, the other components may be a ventilation device including a filter, a fan, etc.

[0056] Figure 3 is a cross-sectional view taken along line A-A' shown in Figure 2, and Figure 4 is an enlarged cross-sectional view of area B shown in Figure 3.

[0057] Referring to FIGS. 3 and 4, the upper plate (200) includes a glass ceramic substrate (210), a hard coating layer (220), and an encapsulating layer (230). The glass ceramic substrate (210), the hard coating layer (220), and the encapsulating layer (230) have a form in which they are laminated in a vertical direction (DR3).

[0058] The glass ceramic substrate (210) may include a lithium aluminosilicate-based crystalline glass having Li2O, Al2O3, and SiO2 as a basic composition for heat resistance characteristics. In the present embodiment, the color of the glass ceramic substrate (210) may vary depending on the content of elements contained in the glass ceramic substrate (210). More specifically, the glass ceramic substrate (210) may further include one or more elements selected from the group consisting of V, Mg, P, Fe, Ti, Cr, and Zr depending on the color to be implemented, but is not limited thereto. For example, when implementing a white color, the P and Zr contents of the glass ceramic substrate (210) may increase, and when implementing a black color, the V content may increase.

[0059] The crystal phase of the glass ceramic substrate (210) according to the present embodiment varies depending on the crystallization temperature, and the color of the glass ceramic substrate (210) may vary depending on the crystal phase. That is, the glass ceramic substrate (210) may include at least one crystal phase of beta-quartz, beta-spodumene, or beta-eucryptite. For example, when the glass ceramic substrate (210) has a beta-quartz crystal phase, it may implement a transparent color, and when it has a beta-spodumene crystal phase, it may implement a white color.

[0060] In a preferred embodiment of the present invention, the glass ceramic substrate (210) may be transparent, and in a more preferred embodiment, the glass ceramic substrate (210) may have a white color. When the glass ceramic substrate (210) has a white color, the glass ceramic substrate (210) may include a beta-spodumene crystal phase and may have an L* value of 80 or more and 100 or less in the CIE Lab* color space.

[0061] In Fig. 11a, a table is shown measuring the composition and composition ratio of the glass ceramic substrate in the case of a glass ceramic substrate having a white color.

[0062] In this embodiment, the Mohs hardness of the glass ceramic substrate (210) may be 4.5 or more and 5.5 or less, and the nanoindentation may be 6 GPa or more and 7 GPa or less.

[0063] Additionally, the thickness of the glass ceramic substrate (210) according to the present embodiment may be about 4 mm. However, the present invention is not particularly limited to the thickness of the glass ceramic substrate (210).

[0064] A hard coating layer (220) and an encapsulating layer (230) are disposed on a glass ceramic substrate (210). The hard coating layer (220) and the encapsulating layer (230) define a reinforced laminate (not shown). The hard coating layer (220) and the encapsulating layer (230) may have the same thermal expansion coefficient as the glass ceramic substrate (210). Therefore, even when the temperature changes due to the heat transferred from the main body (100), peeling or cracking may not occur between the glass ceramic substrate (210), the hard coating (220), and the encapsulating layer (230). For example, the thermal expansion coefficient may be 1 X 10 in a temperature range of 20°C to 650°C. -6 K -1 It could be as follows:

[0065] In the present embodiment, the reinforced laminate (not shown) may be a colorless transparent material. That is, the light transmittance of each of the hard coating layer (220) and the encapsulating layer (230) may be 70% or more. In addition, the color difference (△E) between the hard coating layer (220) and the glass ceramic substrate (210) and the color difference (△E) between the encapsulating layer (230) and the glass ceramic substrate (210) may be 0 or more and 2 or less. Therefore, when the glass ceramic substrate (210) is white, the upper plate (200) may have an L* value of 80 or more and 100 or less in the CIE Lab* color space. That is, according to the present embodiment, the upper plate (220) of a clear white color can be provided.

[0066] In addition, in another embodiment of the present invention, even if the top plate (200) has a color other than white, the color of the top plate (200) can be exposed to the outside through a reinforced laminate (not shown) having high light transmittance, so that top plates (200) of various colors can be implemented.

[0067] In addition, although not shown in the drawing, the hard coating layer (220) according to another embodiment of the present invention may further include an inorganic pigment in addition to the mixture forming the characteristics of the hard coating layer (220). In this case, the hard coating layer (220) may have a specific color, and the color of the hard coating layer (220) may be implemented more clearly by the white-colored glass ceramic substrate (210) disposed under the hard coating layer (220).

[0068] In this embodiment, the Mohs hardness of the reinforced laminate (not shown) may be 6.5 or more and 7.5 or less. In addition, the nanoindentation of the reinforced laminate (not shown) may be 8 GPa or more and 12 GPa or less. Fig. 12 shows a table listing the values ​​obtained by measuring the nanoindentation of the upper plate according to an embodiment of the present invention. During the measurement, the measurement load was 1 mN, and the indenter used was a Berkovich tip.

[0069] The hard coating layer (220) is disposed on the glass ceramic substrate (210). The hard coating layer (220) may include a SiO2-based mixture. In addition, the hard coating layer (220) includes a plurality of calcium aggregate structures (CS). Each of the calcium aggregate structures (CS) has a form in which a plurality of calcium oxides (CaO) or calcium silicates (CaSiO3) are aggregated and bonded. FIG. 11b shows a table measuring the composition and composition ratio of the hard coating layer (220) according to an embodiment of the present invention. That is, the hard coating layer (220) according to an embodiment of the present invention may include, in wt%, O: 46 or more and 51 or less, Si: 34 or more and 38 or less, Al: 6 or more and 7.2 or less, Ca: 2 or more and 5.4 or less, and the remaining other impurities.

[0070] In the present embodiment, calcium aggregate structures (CS) can be formed by a sol-gel process. Specifically, a mixture containing calcium is coated on a glass ceramic substrate (210), and a condensation reaction occurs through a heat treatment process, thereby allowing a plurality of calcium oxides (CaO) or calcium silicates (CaSiO3) to aggregate and bind together. At this time, the diameter of each aggregated calcium aggregate structure (CS) can be 40 nm or more and 60 nm or less.

[0071] According to the present embodiment, calcium aggregate structures (CS) may be distributed at least in an area adjacent to the glass ceramic substrate (210). In a preferred embodiment, on a cross-section perpendicular to the upper surface of the glass ceramic substrate (210), i.e., on a cross-sectional view, the ratio of calcium aggregate structures (CS) per unit volume may increase as the area approaches the upper surface of the glass ceramic substrate (210).

[0072] Specifically, the hard coating layer (220) includes a first portion (221) and a second portion (222). The first portion (221) is disposed on the upper portion of the glass ceramic substrate (210). The first portion (221) includes calcium distributed in the form of calcium aggregate structures (CS). In the present embodiment, the calcium content present in the first portion (221) may be 65% or more and 85% or less of the calcium content present in the entire hard coating layer (220).

[0073] The second portion (222) is positioned above the first portion (221). The second portion (222) includes calcium distributed in a non-aggregated form. That is, the second portion (222) does not include a calcium aggregate structure (CS).

[0074] In the present embodiment, on the cross-section, the thickness ratio of the first portion (221) and the second portion (222) may be 7:3. That is, according to the present embodiment, in an area corresponding to 70% of the thickness of the hard coating layer (220) from the upper surface of the glass ceramic substrate (210), 65% or more and 85% or less of the calcium present in the entire hard coating layer (220) may exist in the form of an aggregated structure (CS).

[0075] According to an embodiment of the present invention, the calcium aggregate structure (CS) performs a function of improving the bonding strength between the glass ceramic substrate (210) and the hard coating layer (220). Specifically, the calcium aggregate structure (CS) can further improve the rigidity of the region of the hard coating layer (220) adjacent to the glass ceramic substrate (210), thereby fixing the hard coating layer (220) to the glass ceramic substrate (210). Therefore, according to an embodiment of the present invention, the scratch resistance of the upper plate (200) can be improved by preventing the hard coating layer (220) from being peeled off from the glass ceramic substrate (210).

[0076] Fig. 5a is a view illustrating the calcium distribution in area B of a conventional top plate. Fig. 5b is a view illustrating the calcium distribution in area B of a top plate according to an embodiment of the present invention.

[0077] The left photographs of Figs. 5a and 5b are images obtained by photographing area B using a transmission electron microscope (TEM) and then using energy dispersive X-ray spectroscopy (EDS). Transmission electron microscopy (TEM) is used to visualize the internal structure of the hard coating layer by passing an electron beam through it, and energy dispersive X-ray spectroscopy (EDS) is used to analyze the chemical composition of the hard coating layer by shooting an electron beam and measuring the X-rays emitted by specific elements.

[0078] The right-hand photos of FIGS. 5a and 5b are drawings showing the area where calcium element exists, as a result of mapping using energy dispersive X-ray spectroscopy (EDS).

[0079] Referring to FIG. 5a, in the conventional hard coating layer (220), even if calcium elements are present, they are uniformly distributed throughout in a non-agglomerated form. In this case, since no aggregated structure exists in the hard coating layer, the hard coating layer has no effect on the bonding strength between the hard coating layer and the glass ceramic substrate (210). However, referring to FIG. 5b, it can be confirmed that in the hard coating layer (220) according to the embodiment of the present invention, multiple aggregated forms of calcium elements exist in an area adjacent to the glass ceramic substrate (210).

[0080] Referring again to FIG. 3, the sealing layer (230) is positioned on top of the hard coating layer (220) to cover the hard coating layer (220). In the present embodiment, the sealing layer (230) may be an anti-fouling coating layer. That is, the sealing layer (230) functions to prevent contaminants such as dust, oil, and water from sticking to the surface of the upper plate (200) and to enable easy cleaning. In the present embodiment, the sealing layer (230) may have water-repellent properties. For example, the sealing layer (230) may include at least one of fluorosilicone, polyfluoroalkylsiloxane, polytetrafluoroethylene (PTFE, Teflon), siloxane, silicone resin, fluoropolymer, and perfluoropolyether. FIG. 11c shows a table measuring the composition and composition ratio of the sealing layer (230) according to an embodiment of the present invention.

[0081] In this embodiment, the encapsulation layer (230) can be formed through a sol-gel process.

[0082] Although not shown in the drawing, the encapsulation layer (230) may be subjected to a satin process before the sol-gel process. The satin process is a process for expressing the texture of the upper plate (200) and is used to impart specific physical properties (e.g., smoothness, reflectivity, durability, etc.) to the surface of the upper plate (200). In particular, in the present embodiment, the satin process may be performed to reduce the visibility of scratches even when the upper plate (200) is scratched from the outside. The satin process includes a blasting process, an etching process, and a polishing process. The blasting process is a process of roughening the surface or removing impurities and oxide layers on the surface by colliding particles sprayed at high pressure with the surface of the material. The etching process may be a process of finely etching the surface of the material mainly by chemical or electrolytic means. The polishing process is a process of smoothing the surface and imparting gloss. In another embodiment of the present invention, the polishing process may be omitted.

[0083] In the present embodiment, the surface roughness of the sealing layer (230) may be 0.3 um or more and 1.0 um or less. In addition, the thickness (d2, FIG. 3) of the sealing layer (230) may be 0.05 um or more and 0.5 um or less. In another embodiment of the present invention, the sealing layer (230) may be omitted.

[0084] Fig. 6a is a drawing illustrating a test for the scratch resistance of a top plate, and Fig. 6b is a photograph of the surface of the top plate before performing the scratch resistance test. In this test, a pot with a load of 3 kg is placed on top of the top plate (200) and a reciprocating motion is repeated 100 times on a flat surface. Thereafter, the surface of the top plate (200) is cleaned and the surface is photographed.

[0085] Fig. 7a is an exemplary photograph of the surface of the upper plate after the scratch resistance test has been completed, and Figs. 7b and 7c are comparative example photographs of the surface of the upper plate after the scratch resistance test has been completed.

[0086] According to an embodiment of the present invention, the thickness of the reinforced laminate (220, 230) defined by the hard coating layer (220) and the sealing layer (230) may be 0.5 um or more and 8 um or less. Unlike the embodiment of the present invention, when the thickness of the reinforced laminate is less than 0.5 um, the scratch resistance characteristics may be reduced. On the other hand, when the thickness of the reinforced laminate exceeds 8 um, the reinforced laminate may be peeled off from the glass ceramic substrate (210).

[0087] Fig. 7a is a top surface photograph of an upper plate (200) having a thickness of a reinforced laminate (220, 230) of 0.5 um or more and 8 um or less, and Fig. 7b is a top surface photograph when the thickness of the reinforced laminate is less than 0.5 um. Fig. 7c is a top surface photograph when the thickness of the reinforced laminate is more than 8 um.

[0088] As shown in Fig. 7a, in the case of the surface of the upper plate (200) in which the thickness of the reinforced laminate (220, 230) is 0.5 um or more and 8 um or less, traces of the pot were generated, but they could be removed. However, as shown in Fig. 7b, the surface of the upper plate in which the thickness of the reinforced laminate is less than 0.5 um was scratched, and traces of coating wear could be confirmed. In addition, as shown in Fig. 7c, the surface of the upper plate in which the thickness of the reinforced laminate is more than 8 um was also scratched, and symptoms of coating peeling could be confirmed.

[0089] Fig. 8a is an exemplary photograph of the surface of the upper plate after the scratch resistance test has been completed, and Fig. 8b is a comparative photograph of the surface of the upper plate after the scratch resistance test has been completed. The test performed on the upper plate of Figs. 8a and 8b is as illustrated in Fig. 6a.

[0090] As described above, according to an embodiment of the present invention, since the hard coating layer (220) having a hardness superior to that of the glass ceramic substrate (210) has improved bonding strength with the glass ceramic substrate (210) due to the calcium aggregate structure (CS), the scratch resistance of the upper plate (200) can be improved. FIG. 8a is a top surface photograph of the upper plate (200) when the hard coating layer (220) includes the calcium aggregate structure (CS), and FIG. 8b is a top surface photograph of the upper plate when the hard coating layer does not include the calcium aggregate structure.

[0091] As illustrated in Fig. 8a, when the hard coating layer (220) includes calcium aggregate structures (CS), the surface of the top plate (200) showed traces of the pot, but these were removable. However, as illustrated in Fig. 8b, when the hard coating layer does not include calcium aggregate structures, the surface of the top plate showed scratches, and these were impossible to remove.

[0092] FIG. 9 is a cross-sectional view taken along line A-A' of a top plate according to another embodiment of the present invention.

[0093] Referring to FIG. 9, the upper plate (200-1) according to another embodiment of the present invention may further include a printing layer (240). Furthermore, in the present embodiment, the glass ceramic substrate (210) may be colorless and transparent. For example, the glass ceramic substrate (210) may have a beta-quartz crystal phase.

[0094] The printing layer (240) is disposed under the glass ceramic substrate (210-1). The printing layer (240) may have lower light transmittance than the glass ceramic substrate (210-1) and the reinforced laminate (220, 230). Therefore, the printing layer (240) may be exposed through the glass ceramic substrate (210-1) and the reinforced laminate (220, 230). That is, by exposing the printing layer (240), the color of the upper plate (200) may be implemented.

[0095] Fig. 10 is a cross-sectional view taken along line A-A' of a top plate according to another embodiment of the present invention.

[0096] Referring to FIG. 10, the hard coating layer (220-2) of the upper plate (200-2) according to another embodiment of the present invention may include a plurality of unit coating layers (220_1 to 220_n). The plurality of unit coating layers (220_1 to 220_n) are stacked in the vertical direction (DR3) to have a stacked body shape. In the present embodiment, only at least some of the unit coating layers (220_1 to 220_n) among the unit coating layers (220_1 to 220_n) may include calcium aggregate structures (CS). That is, the calcium aggregate structures (CS) may be distributed in some of the unit coating layers (220_1 to 220_n) arranged adjacent to the glass ceramic substrate (210).

[0097] According to the present embodiment, since the hard coating layer (220-2) is divided into multiple layers and laminated, the possibility of peeling can be reduced compared to the hard coating layer (220-2) formed as a single layer. Accordingly, the scratch resistance of the upper plate (200-2) can be further improved.

[0098] FIG. 13 is a photograph of a Mohs hardness tester for measuring the Mohs hardness of a glass ceramic substrate (210) or top plate (200) according to an embodiment of the present invention.

[0099] Referring to Figure 13, this test measures Mohs hardness using the following method. First, a sample is placed on the tester, the tip angle is set to 70 degrees, and a 200g counterweight is placed on the tester. Then, the handle is pulled, and the fixed sample is scratched five times with the tip, and the surface is cleaned. After the sample is cleaned, the presence of scratches is visually observed. If two or more scratches are found out of five times, the sample is evaluated as having scratched. Meanwhile, if less than 3 scratches were found, the tip was replaced and the test was repeated to finally measure the Mohs hardness. A cooking appliance plate (200) according to an embodiment of the present invention includes a glass ceramic substrate (210) and a hard coating layer (220) disposed on the glass ceramic substrate (210) and including a plurality of calcium aggregate structures (CS) in at least a portion of the hard coating layer (220), and the ratio of the calcium aggregate structures (CS) per unit volume of the hard coating layer (220) increases as it approaches the upper surface of the glass ceramic substrate (210) in a cross-section perpendicular to the upper surface of the glass ceramic substrate (210).

[0100] The hard coating layer (220) includes a first portion that is disposed on the upper portion of the glass ceramic substrate (210) and contacts the upper surface of the glass ceramic substrate (210), and includes calcium distributed in the form of a calcium agglomerated structure, and a second portion that is disposed on the upper portion of the first portion and includes calcium distributed in a non-agglomerated form. The ratio of the calcium content present in the first portion to the calcium content present in the entire hard coating layer is 65% or more and 85% or less.

[0101] The ratio of the thickness of the first portion (221) and the thickness of the second portion (222) is 7:3. The hard coating layer (220) includes, in wt%, O: 46% or more and 51% or less, Si: 34% or more and 38% or less, Al: 6% or more and 7.2% or less, Ca: 2% or more and 5.4% or less, and the remaining other impurities.

[0102] The above glass ceramic substrate (210) includes a lithium aluminosilicate-based crystalline glass having Li2O, Al2O3, and SiO2.

[0103] The diameter of each of the above calcium aggregate structures (CS) is 40 nm or more and 60 nm or less.

[0104] The color difference between the hard coating layer (220) and the glass ceramic substrate (210) is 0 or more and 2 or less.

[0105] The above glass ceramic substrate (210) has an L* value of 80 or more and 100 or less in the CIE Lab* color space.

[0106] In another embodiment of the present invention, the hard coating layer (220) may further include an inorganic pigment.

[0107] The plate (200) for a cooking appliance according to the present embodiment further includes a sealing layer (230) that is placed on top of the hard coating layer (220) and covers the hard coating layer, and the surface roughness of the sealing layer (230) is 0.3 um or more and 1.0 um or less.

[0108] The thickness of the laminate formed by the hard coating layer (220) and the sealing layer (230) may be 0.5 um or more and 8 um or less. In this case, the thickness of the sealing layer (230) is 0.05 um or more and 0.5 um or less.

[0109] The above glass ceramic substrate (210), the hard coating layer (220) and the sealing layer (230) are 1 X 10 in the temperature range of 20℃ to 650℃. -6 K -1It has the following coefficient of thermal expansion.

[0110] The above-mentioned sealing layer (230) has water repellency.

[0111] The plate (200) for a cooking appliance according to an embodiment of the present invention has a Mohs hardness of 6.5 or more and 7.5 or less.

[0112] The plate (200) for a cooking appliance according to an embodiment of the present invention has a nanoindentation of 8 Gpa or more and 12 GPa or less.

[0113] A printing layer (240) is disposed below the glass ceramic substrate (210) and has lower light transmittance than the glass ceramic substrate (210) and the hard coating layer (220), and the printing layer (240) is exposed through the glass ceramic substrate (210) and the hard coating layer (220), so that the color of the cooking appliance plate (200) can be implemented.

[0114] The above hard coating layer (220) has a form in which a plurality of unit coating layers (220_1 to 220_n) are laminated, and the calcium agglomerated structures (CS) are distributed in some of the unit coating layers (220_1 to 220_n) that are arranged adjacent to the glass ceramic substrate (210) among the unit coating layers (220_1 to 220_n).

[0115] A plate (200) for a cooking appliance according to an embodiment of the present invention includes a glass ceramic substrate (210) having a beta-spodumene crystal phase, a hard coating layer (220) disposed on the glass ceramic substrate (210) and including a plurality of calcium aggregate structures (CS) distributed at least in an area adjacent to the glass ceramic substrate (210), and an encapsulating layer (230) disposed on the hard coating layer (220) and covering the hard coating layer (220), and has an L* value of 80 or more and 100 or less in the CIE Lab* color space.

[0116] The color difference between the hard coating layer (220) and the sealing layer (230) and the glass ceramic substrate is 0 or more and 2 or less.

[0117] The light transmittance of each of the hard coating layer (220) and the sealing layer (230) is 70% or more.

[0118] The thickness of the laminate formed by the hard coating layer (220) and the sealing layer (230) is 0.5 um or more and 8 um or less.

[0119] The above hard coating layer (220) contains, in wt%, O: 46 or more and 51 or less, Si: 34 or more and 38 or less, Al: 6 or more and 7.2 or less, Ca: 2 or more and 5.4 or less, and the remaining other impurities.

[0120] The surface roughness of the above-mentioned sealing layer (230) is 0.3 or more and 1.0 um or less.

[0121] The plate for a cooking appliance according to the present embodiment has a Mohs hardness of 6.5 or more and 7.5 or less, and a nanoindentation of 8 Gpa or more and 12 GPa or less.

[0122] A cooking appliance (1000) according to an embodiment of the present invention includes a main body (100) including a cooking appliance plate (200) on which a cooking vessel (CT) is mounted, and a plurality of induction heating coils (121, 122, 123) arranged at a lower portion of the cooking appliance plate (200) and configured to generate a magnetic field, wherein the cooking appliance plate (200) includes a glass ceramic substrate (210), and a colorless and transparent hard coating layer (220) arranged on the glass ceramic substrate (210), and wherein the hard coating layer (220) includes a plurality of calcium aggregate structures (CS) each having a diameter of 40 nm or more and 60 nm or less.

[0123] Unlike the embodiment of the present invention, conventional ceramic glass had a limited material composition for forming a hard coating layer in order to secure a certain level of mechanical strength or higher, and had a problem in that the light transmittance of the hard coating layer was low due to the material composition. That is, conventional hard coating layers were colored rather than transparent, making it difficult to implement cooking utensils of various colors. However, according to the embodiment of the present invention, even if the hard coating layer (220) is colorless and transparent, a certain level of mechanical strength or higher can be secured, so that a cooking utensil plate that can be implemented in various colors can be provided. In particular, when implementing a white-colored cooking utensil plate, excellent scratch resistance can be secured even if a colorless and transparent hard coating layer (220) is applied.

[0124] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0125] The above illustrates and describes specific embodiments. However, the invention is not limited to the above-described embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. Glass ceramic substrate; and A hard coating layer is disposed on the glass ceramic substrate and includes a plurality of calcium aggregate structures in at least a portion of the substrate, The above hard coating layer is, A plate for cooking appliances, wherein the proportion of calcium aggregate structures per unit volume increases as the glass ceramic substrate approaches the upper surface thereof in a cross-section perpendicular to the upper surface thereof.

2. In paragraph 1, The above hard coating layer is, A first part disposed on the upper part of the glass ceramic substrate and in contact with the upper surface of the glass ceramic substrate, and including calcium distributed in the form of the calcium agglomerate structure; and A cooking plate comprising a second portion disposed on the upper portion of the first portion and containing calcium distributed in a non-agglomerated form.

3. In paragraph 2, A cooking plate having a calcium content present in the first portion of the cooking appliance that is 65% or more and 85% or less of the calcium content present in the entire hard coating layer.

4. In paragraph 2, A plate for a cooking appliance, wherein the ratio of the thickness of the first portion and the thickness of the second portion is 7:

3.

5. In paragraph 1, The above hard coating layer is, A plate for cooking utensils containing, by weight %, O: 46% or more and 51% or less, Si: 34% or more and 38% or less, Al: 6% or more and 7.2% or less, Ca: 2% or more and 5.4% or less and the remaining other impurities.

6. In paragraph 1, The above glass ceramic substrate is a plate for a cooking appliance, comprising a lithium aluminosilicate crystalline glass having Li2O, Al2O3 and SiO2.

7. In paragraph 1, A plate for a cooking appliance, wherein each of the above calcium aggregate structures has a diameter of 40 nm or more and 60 nm or less.

8. In paragraph 1, A plate for a cooking appliance, wherein the color difference between the hard coating layer and the glass ceramic substrate is 0 or more and 2 or less.

9. In paragraph 1, The above glass ceramic substrate is a plate for cooking appliances having an L* value of 80 or more and 100 or less in the CIE Lab* color space.

10. In paragraph 9, A plate for cooking appliances wherein the hard coating layer further comprises an inorganic pigment.

11. In paragraph 9, Further comprising a sealing layer disposed on top of the hard coating layer and covering the hard coating layer, A plate for cooking appliances having a surface roughness of the above-mentioned sealing layer of 0.3 um or more and 1.0 um or less.

12. In paragraph 11, A plate for a cooking appliance, wherein the thickness of the laminate formed by the hard coating layer and the sealing layer is 0.5 um or more and 8 um or less.

13. In paragraph 11, The above glass ceramic substrate, the hard coating layer and the sealing layer are 1 X 10 in the temperature range of 20℃ to 650℃. -6 K -1 A plate for a cooking appliance having the following coefficient of thermal expansion.

14. In paragraph 11, The above-mentioned sealing layer is a cooking plate having water-repellent properties.

15. In paragraph 1, A plate for cooking utensils with a Mohs hardness of 6.5 or higher and 7.5 or lower.

Images