Planar heating element and electric oven comprising same

Abstract

An electric oven according to an example may comprise: a cavity which is provided with an upper plate, a bottom plate, both side plates, and a rear plate arranged to face each other and has an open front surface; a door which selectively opens / closes the front surface of the cavity; and a planar heating element which is provided on one surface of one or more of the upper plate, the bottom plate, both side plates, and the rear plate and applies heat to the cavity.

Description

Planar heating element and electric oven including the same

[0001] The present invention relates to a planar heating element and an electric oven equipped with the same, wherein the electric oven is equipped with a planar heating element to raise the temperature inside the cavity relatively uniformly.

[0002] Conventional planar heating elements that generate heat when electricity is applied are hygienic as they do not contaminate the air, and because they are easy to control in terms of temperature and are noiseless, they can be used in residential heating devices such as apartments or general houses that require heating, as well as in cooking heating devices. An electric oven, which is one of the cooking heating devices, can use an electric heater as a heat source, and in this case, a planar heating element can be used as the electric heater.

[0003] The above-described planar heating element is positioned on one side inside a cavity provided in an electric oven and can heat food by natural convection or forced convection by applying heat to the cavity. When a plurality of planar heating elements are provided as electric heaters in an electric oven, the planar heating elements may be exposed to a high temperature and humid environment during the cooking process.

[0004] According to one example, a planar heating element may include a graphene layer and a graphene oxide layer disposed to surround the graphene layer.

[0005] According to one example, the planar heating element may further include an inorganic oxide film disposed on top of the graphene oxide film layer.

[0006] According to one example, the planar heating element may further include a first electrode disposed to be electrically connected to the graphene layer and a second electrode disposed to be electrically connected to the graphene layer and spaced apart from the first electrode with the graphene layer in between.

[0007] According to one example, the electric oven may include a top plate, a bottom plate, two side plates and a rear plate arranged to face each other, and may include a cavity with an open front.

[0008] According to one example, the electric oven may further include a door that selectively opens and closes the front of the cavity.

[0009] According to one example, the electric oven may further include a planar heating element disposed on one or more of the top plate, the bottom plate, the two side plates and the rear plate to apply heat to the cavity.

[0010] The above and other aspects, features, and advantages of specific embodiments of the present disclosure will become more apparent from the following description together with the accompanying drawings.

[0011] Figure 1 is a drawing illustrating an electric oven according to one example.

[0012] FIG. 2 is a schematic diagram showing a cross-sectional view of an electric oven according to one example.

[0013] FIG. 3 is a schematic drawing illustrating the upper surface of an electric oven according to one example.

[0014] FIG. 4 is a perspective view of a planar heating element disposed on one surface of a body defining a cavity according to one example.

[0015] FIG. 5 is a perspective view of a planar heating element disposed on one surface of a body defining a cavity according to one example.

[0016] FIG. 6 is a schematic diagram illustrating the upper surface of an electric oven in which a planar heating element is arranged according to one example.

[0017] FIG. 7 is a schematic diagram illustrating the upper surface of an electric oven in which a planar heating element is arranged to check the cooking process of food according to one example.

[0018] FIG. 8 is a schematic diagram illustrating the upper surface of an electric oven in which a planar heating element is arranged according to one example.

[0019] Figure 9 is a cross-sectional view of a planar heating element according to one example.

[0020] FIGS. 10a to 10f are drawings for explaining a method of forming a planar heating element according to one example.

[0021] Figure 11a is a photograph of an inorganic oxide film layer according to one example.

[0022] Figure 11b is a photograph of an inorganic oxide film layer according to a comparative example.

[0023] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0024] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0025] The singular form of the noun corresponding to an item may include one or plural items, unless the relevant context clearly indicates otherwise.

[0026] In this document, each of the phrases such as "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.

[0027] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in other aspects (e.g., importance or order).

[0028] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that the component may be connected to the other component directly (e.g., via a wire), wirelessly, or through a third component.

[0029] Terms such as “include” or “have” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0030] When it is said that one component is “connected,” “combined,” “supported,” or “in contact” with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0031] When it is said that a component is located “on” another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0032] The term “and / or” includes a combination of multiple related described components or any of the multiple related described components.

[0033] The operating principle and embodiments of the present invention will be described below with reference to the attached drawings.

[0034] FIG. 1 is a drawing illustrating an electric oven according to one example. FIG. 2 is a schematic drawing illustrating a front cross-section of an electric oven according to one example. FIG. 3 is a schematic drawing illustrating a top surface of an electric oven according to one example.

[0035] Referring to FIGS. 1 to 3, an electric oven (1) according to one example may include a case (10) and a cavity (20) provided inside the case (10). The case (10) may have a front opening that exposes the cavity (20). The electric oven (1) may form an exterior by having a door (30) rotatably coupled to one side of the case (10) to open and close the front opening of the cavity (20).

[0036] The case (10) may be positioned so as to be spaced apart from the cavity (20), which will be described later, by a predetermined distance. According to one example, the case (10) may include a transparent substrate. According to one example, if the case (10) is provided with a transparent substrate, not only can the food being cooked inside the cavity (20) be checked by improving visibility, but the aesthetic characteristics of the electric oven (1) can also be enhanced. According to one example, the case (10) may include one or more of tempered glass, ceramic, and quartz. However, the present disclosure is not limited thereto, and the case (10) may include any transparent material capable of transmitting visible light so that an external user can observe the inside of the cavity (20).

[0037] The cavity (20) is a cooking space formed by a top plate (21), a bottom plate (22), two side plates (23), and a rear plate (24). A front plate (27) forming a front opening may be provided on the front of the cavity (20). According to one example, the case (10) may be positioned so as to be spaced apart from the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) by a predetermined distance. Various components constituting an electric oven (1) may be housed in the space provided between the cavity (20) and the case (10), for example, the space provided between one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) and the case (10).

[0038] At least one rack (90) for placing food can be placed inside the cavity (20). Rails can be installed on the inner sides of the two side plates (23) so that the rack (90) can be attached and detached. The user can move the rack (90) along the rails (91) to take out or place food.

[0039] The door (30) can be installed by hinge-connecting it to the bottom of the case (10) so that the user can open and close the cavity (20). A handle (37) can be attached to the top of the door (30) so that the user can conveniently rotate the door (30).

[0040] A vent (92) may be installed in the rear plate (24) to allow the air inside the cavity (20) to escape to the outside. The vent (92) may be formed by penetrating the rear plate (24) so ​​that the air inside the cavity (20) can pass through the rear plate (24) through the vent (92). A filter capable of filtering contaminants from the air escaping from the cavity (20) may be installed in the vent (92).

[0041] A planar heating element (100) is a heating element that is disposed between a case (10) and a cavity (20) and can apply heat to the cavity (20). As an example, the planar heating element (100) may be formed as one or more, and each of the one or more planar heating elements (100) is disposed to face any one of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) that define the cavity (20) 400 0It can be heated to a high temperature of C or higher. For example, it may be equipped with five planar heating elements (100), and each planar heating element (100) may be arranged to face the top plate (21), bottom plate (22), two side plates (23), and rear plate (24), respectively. As described above, by arranging the planar heating elements (40) to correspond to the top plate (21), bottom plate (22), and two side plates (23), not only can the heating rate inside the cavity (20) be increased, but a uniform temperature rise inside the cavity (20) can also be generated.

[0042] In order to insulate the cavity (20) from the outside, an insulating section (50) may be placed between the top plate (21), bottom plate (22), two side plates (23), rear plate (24) and the case (10). Additionally, a control panel (60) for controlling the operation of the electric oven (1) may be installed on the top of the case (10).

[0043] The insulation part (50) can block heat transfer between the case (10) and the planar heating element (100) so that heat generated from the planar heating element (100) is not transferred to the user. According to one example, when the planar heating element (100) is placed in a space formed between the case (10) and the top plate (21), bottom plate (22), two side plates (23), and rear plate (24), the insulation part (50) is placed between the case (10) and the top plate (21), bottom plate (22), and two side plates (23) to insulate the cavity (20) from the outside.

[0044] According to one example, the insulating part (50) may include a transparent material. As described above, in order to improve visibility so that food being cooked inside the cavity (20) can be checked, as well as to enhance aesthetic characteristics, if the substrate defining the case (10), the planar heating element (100), and the cavity (20) is implemented as a transparent structure capable of transmitting visible light, the insulating part (50) placed in the space between the case (10) and the cavity (20) may also include a transparent material. According to one example, the insulating part (50) may include one or more of tempered glass, ceramic, and quartz. However, the present disclosure is not limited thereto, and the insulating part (50) may include any transparent material capable of transmitting visible light so that an external user can observe the inside of the cavity (20).

[0045] Below, the structure of a planar heating element (100) that is used as an electric heater and is positioned outside the cavity (20) is described in more detail.

[0046] FIG. 4 is a perspective view of a planar heating element disposed on one surface of a body defining a cavity according to one example. FIG. 5 is a perspective view of a planar heating element disposed on one surface of a body defining a cavity according to one example.

[0047] Referring to FIGS. 2 and 4, a planar heating element (100) according to one example is a heating element that is disposed between a case (10) and a cavity (20) and can apply heat to the cavity (20). As an example, the planar heating element (100) may be formed as one or more, and each of the one or more planar heating elements (100) may be disposed on at least one surface of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) provided in the cavity (20) to heat the cavity (20) to a high temperature. For example, the temperature of the cavity (20) heated by the planar heating element (100) is 400 oC or more may be used, but the present disclosure is not limited thereto.

[0048] According to one example, a planar heating element (100) may be placed on one surface of a top plate (21), a bottom plate (22), two side plates (23), and a rear plate (24) provided in a cavity (20). As described above, by placing the planar heating element (100) to correspond to the top plate (21), the bottom plate (22), the two side plates (23), and the rear plate (24), not only can the heating rate inside the cavity (20) be increased, but a uniform temperature rise inside the cavity (20) can also be generated.

[0049] A planar heating element (100) according to one example may be formed in a planar shape extending along a plane and may include a stacked structure (110), a first electrode (150) and a second electrode (160) positioned between the stacked structure (110). At this time, the first electrode (150) and the second electrode (160) may be positioned to be connected to a power supply unit (180) (e.g., a power supply).

[0050] The laminated structure (110) may be placed on one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) of a body defining a cavity (20), and may be arranged to be in contact with the first electrode (150) and the second electrode (160). Accordingly, the graphene layer (111: see FIG. 9) included in the laminated structure (110) may be electrically connected to the power supply unit (180).

[0051] According to one example, the laminated structure (110) may be implemented as a transparent structure capable of transmitting visible light. As described above, in order to improve visibility so that food being cooked inside the cavity (20) can be seen, as well as to enhance aesthetic characteristics, if the substrate defining the case (10), planar heating element (100), and cavity (20) is implemented as a transparent structure capable of transmitting visible light, the laminated structure (110) placed in the space between the case (10) and the cavity (20) may also include a transparent structure. According to one example, the stacked structure (110) may include a graphene layer (111; see FIG. 9) that generates heat, a graphene oxide layer (113; see FIG. 9) disposed to surround the graphene layer (111), an inorganic oxide layer (115; see FIG. 9) disposed on top of the graphene oxide layer (113), and a reduced graphene oxide layer (117; see FIG. 9) disposed on top of the inorganic oxide layer (115). The characteristics of each layered structure included in the stacked structure (110) and the transparent characteristics of the layered structure will be described later with reference to FIG. 9 to FIG. 11b.

[0052] The first electrode (150) and the second electrode (160) may be disposed on one side of a body defining a cavity (e.g., one side of the top plate (21)) and may be disposed to be in direct contact with the laminated structure (110). As an example, the first electrode (150) and the second electrode (160) may include a material having excellent electrical conductivity, for example, the first electrode (150) and the second electrode (160) may include at least one of Ag, Al, ITO (Indium Tin Oxide), Cu, Mo, and Pt.

[0053] According to one example, when a plurality of stacked structures (110) are provided, the stacked structures (110) may be arranged to be spaced apart with a predetermined interval between them. As an example, as shown in FIG. 4, the stacked structures (110) may be arranged to extend along one direction and placed on one side of a body (e.g., one side of a top plate (21)) that defines a cavity. At this time, the stacked structures (110) may be arranged to be spaced apart from each other with a predetermined interval between them.

[0054] According to one example, the first electrode (150) and the second electrode (160) may be spaced apart with respect to the laminated structure (110). For example, the first electrode (150) may be positioned to contact one end of the laminated structure (110), and the second electrode (160) may be positioned to contact one end of the laminated structure (110). The first electrode (150) and the second electrode (160) positioned at both ends of the laminated structure (110) may include an opaque material that cannot transmit visible light.

[0055] According to one example, when the first electrode (150) and the second electrode (160) include an opaque material that cannot transmit visible light, the width (W: see FIG. 6) of the first electrode (150) and the second electrode (160) may have a fine line shape with a width of 5 mm or more and 10 mm or less. Accordingly, the first electrode (150) and the second electrode (160) may not substantially affect the user's field of vision during the process of checking food being cooked inside the cavity (20). However, the present disclosure is not limited thereto, and the first electrode (150) and the second electrode (160) may be implemented as transparent electrodes including a transparent material or may have other widths that do not substantially affect the user's field of vision.

[0056] In addition, according to one example, when a plurality of stacked structures (110) are provided, the stacked structures (110) may be arranged so as to be spaced apart from each other with a predetermined spacing. At this time, the plurality of stacked structures (110) may be arranged so as to be spaced apart from each other with a predetermined spacing, and may also be arranged in a grid form forming a plurality of rows as shown in FIG. 5, depending on the arrangement of the first electrode (150) and the second electrode (160).

[0057] For example, as illustrated in FIG. 5, when a plurality of first electrodes (150) are provided, each first electrode (150) may be arranged so as to be spaced apart from each other with a predetermined interval between them. Additionally, one or more second electrodes (160) may be formed to correspond to the first electrode (150) and may be placed on one surface of the body (e.g., one surface of the upper plate (21)) that defines the cavity. For example, when a plurality of second electrodes (160) are provided, each second electrode (160) may be arranged so as to be spaced apart from each other with a predetermined interval between them. In addition, the first electrode (150) and the second electrode (160) may be arranged alternately to correspond one-to-one with each other.

[0058] According to one example, the first electrode (150) and the second electrode (160) may include a transparent electrode capable of transmitting visible light. Accordingly, the first electrode (150) and the second electrode (160) may not be visible to the user's field of vision during the process of checking food being cooked inside the cavity (20). However, the present disclosure is not limited thereto, and if the first electrode (150) and the second electrode (160) include an opaque material, the first electrode (150) and the second electrode (160) may be provided with a small width and length that does not substantially affect the user's field of vision.

[0059] FIG. 6 is a schematic drawing of the upper surface of an electric oven in which a planar heating element is arranged according to one example. FIG. 7 is a schematic drawing of the upper surface of an electric oven in which a planar heating element is arranged so that the cooking process of food is observed according to one example. FIG. 8 is a schematic drawing of the upper surface of an electric oven in which a planar heating element is arranged according to one example.

[0060] Referring to FIGS. 6 and 7, a support substrate on which a planar heating element (100) according to one example is placed may be provided in the shape of a flat plane on which a laminated structure (110), a first electrode (150), and a second electrode (160) can be placed. At this time, for convenience of explanation, the support substrate on which the planar heating element (100) is placed is shown as one side of a body defining a cavity (20), for example, a top plate (21), but the present disclosure is not limited thereto. As an example, the support substrate on which the planar heating element (100) is placed may be one or more of one side of a body defining a cavity (20), for example, a top plate (21), a bottom plate (22), two side plates (23), and a rear plate (24).

[0061] According to one example, one or more of the surfaces of the body defining the cavity (20) in which the planar heating element (100) is placed, such as the top plate (21), bottom plate (22), two side plates (23) and a rear plate (24), may include a transparent substrate. According to one example, in order to improve visibility so that food being cooked inside the cavity (20) can be seen, as well as to enhance aesthetic characteristics, one surface of the body defining the cavity (20) in which the planar heating element (100) is placed may include a transparent substrate.

[0062] According to one example, one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) may include a transparent material having heat resistance. For example, the transparent material included in one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) may include one or more of tempered glass, ceramic, and quartz glass. However, the present disclosure is not limited thereto, and one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) may be 400 o It may also include any transparent material having heat resistance to high temperatures of C or higher.

[0063] As described above, when one side of the body defining the cavity (20) includes a transparent substrate, visible light can be transmitted along the case (10), the insulating part (50), the laminated structure (110) included in the planar heating element (100), and one side of the body defining the cavity (e.g., the upper plate (21)). Accordingly, as shown in FIG. 7, the user's visibility during the cooking process can be improved by checking the food being cooked inside the cavity (20). According to one example, the first electrode (150) and the second electrode (160) included in the planar heating element (100) may include a transparent electrode or be provided in the form of a thin line having a predetermined width (W), so that they may not substantially affect the user's field of vision.

[0064] As described above, when the first electrode (150) and the second electrode (160) include an opaque material, the width (W) of the first electrode (150) and the second electrode (160) can be adjusted so as not to substantially affect the user's field of vision. However, for design convenience, if the width (W) of the first electrode (150) and the second electrode (160) exceeds a predetermined range, the first electrode (150) and the second electrode (160) may substantially affect the user's field of vision.

[0065] Referring to FIG. 8, a bezel portion (16) according to one example is placed on a case (10) and may be placed in an area corresponding to a first electrode (150) and a second electrode (160). As an example, the bezel portion (16) may be a decorative member that covers the first electrode (150) and the second electrode (160) so that they are not visible from the user's view. For example, the bezel portion (16) may be an opaque decorative member having various colors or shapes. As the bezel portion (16) is placed to cover the first electrode (150) and the second electrode (160), the user may not be able to see the first electrode (150) and the second electrode (160) while checking the cooking process, and the aesthetic effect of the electric oven (1) may be improved.

[0066] Referring again to FIGS. 2 and FIGS. 6, as described above, one or more of the top plate (21), bottom plate (22), two side plates (23), and rear plate (24) may include a transparent substrate to improve visibility. At this time, the remaining substrates that do not include a transparent substrate may include an opaque substrate. As an example, if the electric oven (1) is provided in a recessed structure in which only the top surface and the door (30) are exposed to the outside, only the top plate (21) may include a transparent substrate. At this time, the upper surface of the case (10) corresponding to the top plate (21), the planar heating element (100) and the insulation part (50) placed between the top plate (21) and the upper surface of the case (10) may also be provided to transmit visible light. Also, at this time, the bottom plate (22), two side plates (23), and rear plate (24), excluding the top plate (21), may include an opaque substrate for ease of manufacturing. At this time, the remaining area of ​​the case (10) corresponding to the bottom plate (22), two side plates (23) and the rear plate (24), and the planar heating element (100) and the insulation part (50) disposed between the bottom plate (22), two side plates (23) and the rear plate (24) may also be provided with an opaque structure that cannot transmit visible light.

[0067] As another example, when the electric oven (1) is provided with an exposed structure in which only the top surface, two side surfaces, a rear surface, and a door (30) are exposed to the outside, the top surface plate (21), two side surfaces (23), and a rear surface plate (24) and the corresponding top surface, two side surfaces, a rear surface of the case (10), the top surface, both side surfaces, a rear surface of the case (10), and the planar heating element (100) and insulation part (50) disposed between the top surface plate (21), two side surfaces (23), and a rear surface plate (24) may include a transparent structure. At this time, the bottom plate (22) and the bottom surface of the case (10), and the planar heating element (100) and insulation part (50) disposed between the bottom plate (22) and the bottom surface of the case (10) may include an opaque structure for ease of manufacturing.

[0068] As another example, even if the electric oven (1) is provided with an exposed structure in which only the top surface, two side surfaces, a rear surface, and a door (30) are exposed to the outside, for aesthetic purposes, one or more of the top surface plate (21), two side plates (23), and a rear plate (24) exposed to the outside, for example, the area of ​​the case (10) corresponding to the two side plates (23) and the rear plate (24), and the planar heating element (100) and the insulation part (50) disposed between the case (10) and the two side plates (23) and the rear plate (24) may include an opaque structure.

[0069] When one or more of the top plate (21), bottom plate (22), two side plates (23) and rear plate (24) include an opaque substrate, the opaque substrate may be implemented as a support substrate including a metal material. At this time, an enamel substrate surrounding the opaque substrate may be placed between the opaque substrates. The enamel substrate surrounding the opaque substrate may include a plastic material such as enamel.

[0070] Below, the structure of a planar heating element (100) placed on one side of a body defining a cavity (20) of an electric oven is described in more detail. For convenience of explanation, the one side of the body defining the cavity (20) where the planar heating element (100) is placed is described as an upper plate (21), but it is obvious that it can also be applied to a bottom plate (22), two side plates (23), and a rear plate (24).

[0071] Figure 9 is a cross-sectional view of a planar heating element according to one example.

[0072] Referring to FIG. 9, a planar heating element (100) according to one example may include a stacked structure (110) disposed on one side of a body (e.g., a top plate (21)) defining a cavity (20), a first electrode (150) and a second electrode (160) disposed on opposite sides with the stacked structure (110) in between. As an example, the stacked structure (110) may include a graphene layer (111) having a predetermined thickness that extends along one plane, a graphene oxide layer (113) disposed to surround the graphene layer (111), an inorganic oxide layer (115) disposed on top of the graphene oxide layer (113), and a reduced graphene oxide layer (117) disposed on top of the inorganic oxide layer (115).

[0073] The graphene layer (111) may be provided on one side of a body (e.g., a top plate (21)) defining a cavity (20) and may be positioned to be in contact with the first electrode (150) and the second electrode (160) between the first electrode (150) and the second electrode (160). Accordingly, the graphene layer (111) may be electrically connected to the first electrode (150) and the second electrode (160). The first electrode (150) and the second electrode (160) may be connected to a power supply unit (180: see FIG. 4), and accordingly, the graphene layer (111) may generate heat by receiving a predetermined voltage from the power supply unit (180).

[0074] According to one example, the graphene layer (111) may be a single layer of graphene or a multilayer graphene structure in which a plurality of graphene layers are stacked. As an example, the graphene layer (111) may have a predetermined thickness (T1), for example, a thickness of 1 nm or more and 5 nm or less. Accordingly, the graphene layer (111) may be a transparent material layer capable of transmitting visible light. Additionally, the graphene layer (111) may have a resistance capable of generating high-temperature heat. However, the present disclosure is not limited thereto, and the thickness of the graphene layer (111) may be determined differently depending on the heating temperature of the cavity (20) and the arrangement area of ​​the planar heating element (100).

[0075] A graphene oxide layer (113) is positioned between a graphene layer (111) and an inorganic oxide layer (115) to bond the graphene layer (111) and the inorganic oxide layer (115). Additionally, according to one example, the graphene oxide layer (113) is positioned to surround the graphene layer (111) and may be a passivation layer that protects the graphene layer (111). According to one example, the graphene oxide layer (113) is positioned to surround the graphene layer (111) to prevent the graphene layer (111) from oxidizing in a high temperature, oxygen, and moisture atmosphere.

[0076] According to one example, a graphene oxide layer (113) can be formed by performing an oxidation process on a graphene layer (111) having a predetermined thickness to oxidize a portion of the graphene layer (111). As an example, when a graphene layer (111) having a predetermined thickness is disposed and an oxidation process is performed on the graphene layer (111) using an oxidation process for graphene, a graphene oxide layer (113) can be formed along the thickness direction from the outermost surface of the graphene layer (111).

[0077] According to one example, when the oxidation process is completed, the ratio of the thickness (T2) of the graphene oxide layer (113) to the thickness (T1) of the graphene layer (111) may be, for example, 3:1 to 5:1. At this time, the thickness (T2) of the graphene oxide layer (113) may be 0.3 nm or more and 1 nm or less. However, the present disclosure is not limited thereto, and the thickness (T2) of the graphene oxide layer (113) may be set differently depending on the adhesion between the graphene layer (111) and the inorganic oxide layer (115) and the need to protect the graphene layer (111).

[0078] The inorganic oxide layer (115) is disposed on top of the graphene oxide layer (113) and may be a passivation layer that protects the graphene layer (111). As an example, the inorganic oxide layer (115) may be disposed on top of the graphene layer (111) to prevent the graphene layer (111) from oxidizing in a high temperature, oxygen, and moisture atmosphere. According to one example, the inorganic oxide layer (115) may include an inorganic oxide capable of securing sealing properties and visible light transmission properties for the graphene layer (111). For example, the inorganic oxide layer (115) may include one or more of SiO2, TiO2, Si3N4, and MoO3.

[0079] According to one example, the inorganic oxide film layer (115) may be provided as a transparent material layer to ensure visibility so that an external user can check the cooking process inside the cavity (20). As an example, the inorganic oxide film layer (115) may be provided in the form of a thin film having a predetermined thickness, for example, a thickness of 10 nm or more and 40 nm or less. Accordingly, the inorganic oxide film layer (115) may be provided as a transparent material layer capable of transmitting visible light. However, the present disclosure is not limited thereto, and the inorganic oxide film layer (115) may have any thickness capable of transmitting visible light.

[0080] As a comparative example, deformation may occur at the interface between the graphene layer and the inorganic oxide layer due to factors such as differences in coefficients of thermal expansion, which may lead to the detachment or peeling of the graphene layer and the inorganic oxide layer. If the graphene layer and the inorganic oxide layer detach or peel, the graphene layer may oxidize as it is exposed to high temperatures, oxygen, and moisture environments. If the graphene layer oxidizes, the heat generation properties may deteriorate.

[0081] According to one example, a graphene oxide layer (113) is placed between a graphene layer (111) and an inorganic oxide layer (115) to bond the graphene layer (111) and the inorganic oxide layer (115). The graphene oxide layer (113) may simultaneously possess the excellent mechanical properties of the graphene layer (111) and the properties of an oxide that can chemically bond with the inorganic oxide layer (115) through oxygen functional groups. Accordingly, the graphene oxide layer (113) can bond the graphene layer (111) and the inorganic oxide layer (115), and prevent the graphene layer (111) and the inorganic oxide layer (115) from detaching or peeling off. Accordingly, the graphene layer (111) can be prevented from oxidizing when exposed to high temperature, oxygen, and moisture environments.

[0082] The reduced graphene oxide layer (117) is placed on top of the inorganic oxide layer (115) and can protect the graphene layer (111). According to one example, the reduced graphene oxide layer (117) may be hydrophobic by performing a reduction process on the graphene oxide layer. By having the reduced graphene oxide layer (117) hydrophobic, the graphene layer (111) can be protected from moisture.

[0083] A reduced graphene oxide layer (117) according to one example may have a predetermined thickness, for example, a thickness of 1 nm or more and 5 nm or less. However, the present disclosure is not limited thereto, and the thickness of the reduced graphene oxide layer (117) may be adjusted differently depending on the moisture atmosphere.

[0084] The first electrode (150) and the second electrode (160) may be arranged to be spaced apart from each other with a graphene layer (111) in between. According to one example, the first electrode (150) and the second electrode (160) may be arranged to be electrically connected to the graphene layer (111) so as to electrically connect the graphene layer (111) and the power supply unit (180; see FIG. 4). As an example, the first electrode (150) and the second electrode (160) may include a material with excellent electrical conductivity. For example, the first electrode (150) and the second electrode (160) may include at least one of Ag, Al, ITO (Indium Tin Oxide), Cu, Mo, and Pt.

[0085] According to one example, the first electrode (150) and the second electrode (160) may be provided as transparent electrodes to ensure visibility so that an external user can check the cooking process inside the cavity (20). As an example, when the first electrode (150) and the second electrode (160) include Indium Tin Oxide (ITO), the first electrode (150) and the second electrode (160) may be provided as a transparent material layer capable of transmitting visible light. However, the present disclosure is not limited thereto, and the first electrode (150) and the second electrode (160) may include an opaque conductive metal material.

[0086] As an example, when the first electrode (150) and the second electrode (160) contain silver (Ag), the first electrode (150) and the second electrode (160) may be provided as an opaque material layer that cannot transmit visible light. In this case, the first electrode (150) and the second electrode (160) may be implemented as thin wires having a predetermined width (W), for example, a width of 5 mm or more and 10 mm or less. Since the first electrode (150) and the second electrode (160) are implemented as thin wires that are not easily visible to the user's field of vision, visibility can be ensured so that an external user can check the cooking process inside the cavity (20) even though the first electrode (150) and the second electrode (160) are positioned.

[0087] Below, a method for forming a planar heating element (100) disposed on one side of a body (e.g., an upper plate (21)) that defines a cavity (20) is described in more detail.

[0088] FIGS. 10a to 10f are drawings for explaining a method of forming a planar heating element according to one example. FIG. 11a is a photograph of an inorganic oxide film layer according to one example. FIG. 11b is a photograph of an inorganic oxide film layer according to a comparative example.

[0089] Referring to FIG. 10a, a graphene layer (111) having a predetermined thickness (T) is disposed on one surface of a body (e.g., a top plate (21)) that defines a cavity (20). According to one example, the graphene layer (111) may be a single layer of graphene or a multilayer graphene structure in which a plurality of graphene layers are stacked. After the graphene layer (111) is grown to have a predetermined thickness, it may be transferred to one surface of a body (e.g., a top plate (21)) that defines a cavity (20). However, the present disclosure is not limited thereto, and the graphene layer (111) may be grown directly on one surface of a body (e.g., a top plate (21)) that defines a cavity (20). The thickness (T) of the graphene layer (111) disposed on one side of the body defining the cavity (20) (e.g., upper plate (21)) may be thicker than the thickness (T1) of the graphene layer (111) provided in the planar heating element (100) shown in FIG. 9.

[0090] Referring to FIG. 10b, a graphene layer (111) placed on one side of a body (e.g., a top plate (21)) defining a cavity (20) is placed inside a reaction chamber (C), and an oxidation process is performed on a portion of the graphene layer (111) to form a graphene oxide film layer (113). When an oxidation process is performed on a graphene layer (111) having a predetermined thickness, a graphene oxide film layer (113) can be formed along the thickness direction from the outermost surface of the graphene layer (111).

[0091] Specifically, a graphene layer (111) placed on one side of a body (e.g., a top plate (21)) that defines the cavity (20) is first placed inside a reaction chamber (C). Ultraviolet light (UV) having a predetermined wavelength (e.g., a wavelength of 254 nm) can be irradiated onto the graphene layer (111) placed inside the reaction chamber (C). The carbon-carbon bonds of the graphene contained in the graphene layer (111) can be broken by the ultraviolet light (UV), thereby forming a space that can bond with oxygen.

[0092] While ultraviolet light (UV) is irradiated into the reaction chamber (C), ozone (O3) capable of forming oxygen functional groups is injected into the reaction chamber (C). The ozone (O3) injected into the reaction chamber (C) can rapidly react with the graphene surface together with active oxygen species generated by the ultraviolet light (UV) to form various oxygen functional groups. According to one example, the concentration of ozone (O3) inside the reaction chamber (C) may be 50 ppm or more and 60 ppm or less.

[0093] The process temperature for oxidizing the graphene contained in the graphene layer (111) may be room temperature. Additionally, the process pressure for oxidizing the graphene contained in the graphene layer (111) may be atmospheric pressure. Additionally, the process time for oxidizing the graphene contained in the graphene layer (111) may be 40 minutes or more and 60 minutes or less. However, this is merely an example, and other process temperatures, process pressures, and process times may be used.

[0094] As the oxidation process for the graphene contained in the graphene layer (111) proceeds, a graphene oxide layer (113) may be formed along the thickness direction from the outermost surface of the graphene layer (111). Accordingly, the thickness (T1) of the graphene layer (111) and the thickness (T2) of the graphene oxide layer (113) may change inversely proportional to each other. For example, if the oxidation process time increases, the thickness (T2) of the graphene oxide layer (113) may increase, while the thickness (T1) of the graphene layer (111) may decrease.

[0095] In the example described above, an ultraviolet ozone treatment oxidation method is disclosed as an oxidation process for a graphene layer (111) having a predetermined thickness, but the present disclosure is not limited thereto. According to one example, an oxidation process for the graphene layer (111) may be carried out using other oxidation processes such as the Hummers method, thermal oxidation, or plasma oxidation.

[0096] Referring to FIG. 10c, an inorganic oxide layer (115) may be deposited on top of a graphene oxide layer (113). The inorganic oxide layer (115) may include an inorganic oxide capable of securing encapsulation properties and visible light transmission properties for the graphene layer (111). For example, the inorganic oxide layer (115) may include one or more of SiO2, TiO2, Si3N4, and MoO3.

[0097] As an example, when depositing SiO2 as an inorganic oxide included in an inorganic oxide film layer (115) using an atomic layer deposition (ALD) process, a precursor for forming SiO2 (e.g., one or more of tetraethyl orthosilicate (TEOS), hexamethyldisilazane (HMDS), and silane (SiH4)) can first be injected into a reaction chamber (C). The precursor injected into the reaction chamber (C) can be adsorbed onto the graphene oxide film layer (113).

[0098] Next, a reaction gas (e.g., one or more of H2O, O2, and O3) can be introduced to react with the adsorbed precursor. As the precursor reacts with the reaction gas, SiO2 can be deposited.

[0099] According to one example, the thickness of the inorganic oxide film layer (115) can be adjusted by periodically repeating the process of supplying a precursor and the process of supplying a reaction gas. According to one example, the process of supplying a precursor and the process of supplying a reaction gas can be adjusted so that the inorganic oxide film layer (115), which can secure sealing film characteristics and visible light transmission characteristics, has a predetermined thickness (T3) (e.g., a thickness of 10 nm or more and 40 nm or less).

[0100] In the example described above, an atomic layer deposition (ALD) process is disclosed as a deposition process for forming an inorganic oxide layer (115), but the present disclosure is not limited thereto, and the inorganic oxide according to one example may be deposited on the upper surface of the graphene oxide layer (113) through any one of a thermal oxidation process, a chemical vapor deposition (CVD), or a sputtering process.

[0101] According to one example, a graphene oxide layer (113) is placed between a graphene layer (111) and an inorganic oxide layer (115) to bond the graphene layer (111) and the inorganic oxide layer (115). The graphene oxide layer (113) can simultaneously possess the excellent mechanical properties of the graphene layer (111) and the properties of an oxide that can chemically bond with the inorganic oxide layer (115) through oxygen functional groups. Accordingly, as shown in FIG. 11a, it can be confirmed that the inorganic oxide layer (115) (e.g., SiO2 layer) bonded by the graphene oxide layer (113) does not develop separate cracks or delamination. On the other hand, as a comparative example, the inorganic oxide layer (115) (e.g., SiO2 layer) directly bonded to the graphene layer (111) can be confirmed to develop cracks or delamination as shown in FIG. 11b.

[0102] As described above, as the graphene oxide layer (113) adheres the graphene layer (111) and the inorganic oxide layer (115), the phenomenon of the graphene layer (111) and the inorganic oxide layer (115) detaching or peeling off can be prevented. Accordingly, the phenomenon of the graphene layer (111) oxidizing when exposed to high temperature, oxygen, and moisture atmospheres can be prevented.

[0103] Referring to FIG. 10d, a graphene oxide layer (116) can be formed on top of an inorganic oxide layer (115). The process of forming the graphene oxide layer (116) on top of the inorganic oxide layer (115) can be carried out through an oxidation process in which the graphene layer (111) shown in FIG. 10a and FIG. 10b is oxidized after the graphene layer (111) is placed. However, at this time, the thickness (T4) of the graphene oxide layer (116) may be 1 nm or more and 5 nm or less, and the entire area of ​​the graphene layer (111) may be oxidized to form the graphene oxide layer (116).

[0104] However, the present disclosure is not limited thereto, and a graphene oxide layer (116) formed through an external oxidation process may be formed by transferring it onto an inorganic oxide layer (115).

[0105] Referring to FIG. 10e, a reduced graphene oxide layer (117) can be formed by performing a reduction process on a graphene oxide layer (116) disposed on top of an inorganic oxide layer (115). By reducing the oxygen functional groups formed on the graphene oxide layer (116), a reduction process for the graphene oxide layer (116) can be performed.

[0106] As an example, when performing a thermal reduction process, a predetermined high temperature, for example, 200 degrees Celsius or higher under vacuum or hydrogen gas, can be applied to the graphene oxide layer (116) for a predetermined process time (e.g., 10 to 30 minutes).

[0107] A reduced graphene oxide layer (117), formed through a reduction process of the graphene oxide layer (116), is placed on top of an inorganic oxide layer (115) and can protect the graphene layer (111). According to one example, the reduced graphene oxide layer (117) can be hydrophobic by performing a reduction process on the graphene oxide layer. By having the reduced graphene oxide layer (117) hydrophobic, the graphene layer (111) can be protected from moisture.

[0108] In the example described above, a thermal reduction process is disclosed as a reduction process for the graphene oxide layer (116), but the present disclosure is not limited thereto, and the graphene oxide layer (116) according to one example may be reduced to a reduced graphene oxide layer (117) through any one of a chemical reduction process, an electrochemical reduction process, a plasma reduction process, or a photoreduction process.

[0109] Referring to FIG. 10f, the first electrode (150) and the second electrode (160) may be formed to be spaced apart from each other with a graphene layer (111) in between. According to one example, the first electrode (150) and the second electrode (160) may be made of a material with excellent electrical conductivity, for example, the first electrode (150) and the second electrode (160) may include at least one of Ag, Al, ITO (Indium Tin Oxide), Cu, Mo, and Pt.

[0110] According to one example, the first electrode (150) and the second electrode (160) may be positioned to be in contact with the graphene layer (111), but may also be positioned to cover a portion of the graphene layer (111) so that the graphene layer (111) is not exposed to the outside. Accordingly, the graphene layer (111) can maintain airtightness so as not to come into contact with moisture or oxygen.

[0111] According to one example, the first electrode (150) and the second electrode (160) may be provided as transparent electrodes to ensure visibility so that an external user can check the cooking process inside the cavity (20). Also, as another example, when the first electrode (150) and the second electrode (160) include an opaque material such as silver (Ag), the first electrode (150) and the second electrode (160) may be implemented as thin wires having a predetermined width (W) (e.g., a width of 5 mm or more and 10 mm or less). Since the first electrode (150) and the second electrode (160) are implemented as thin wires that are not easily visible to the user's field of vision, visibility is ensured so that an external user can check the cooking process inside the cavity (20) even though the first electrode (150) and the second electrode (160) are positioned.

[0112] One aspect of the present disclosure may provide a planar heating element that prevents the graphene layer from being oxidized by moisture and oxygen, thereby preventing the degradation of heating properties.

[0113] One aspect of the present disclosure may provide a planar heating element capable of improving adhesion between graphene and an inorganic oxide layer by placing a graphene oxide layer between a graphene layer and an inorganic oxide layer.

[0114] One aspect of the present disclosure may provide a planar heating element capable of protecting a graphene layer from moisture penetration by disposing of a hydrophobic reduced graphene oxide film layer on the uppermost layer of the planar heating element.

[0115] One aspect of the present disclosure can provide a planar heating element with improved ease of manufacturing.

[0116] One aspect of the present disclosure may provide an electric oven with improved visibility and aesthetic characteristics so that the cooking process can be observed from the outside.

[0117] One aspect of the present disclosure may provide an electric oven having a transparent structure through which visible light can pass from a cavity, which is a cooking space, to a planar heating element, an insulating part, and a case.

[0118] The technical problems to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0119] A planar heating element according to one example may include a graphene layer having a predetermined thickness, a graphene oxide layer disposed to surround the graphene layer, an inorganic oxide layer disposed on top of the graphene oxide layer, a first electrode disposed to be electrically connected to the graphene layer, and a second electrode electrically connected to the graphene layer and disposed to be spaced apart from the first electrode with the graphene layer in between.

[0120] The graphene layer may have a thickness of 1 nm or more and 5 nm or less.

[0121] The ratio of the thickness of the graphene oxide layer (113) to the thickness of the graphene layer may be 3:1 to 5:1.

[0122] The graphene oxide layer may have a thickness of 0.3 nm or more and 1 nm or less.

[0123] The above inorganic oxide film layer may include one or more of SiO2, TiO2, Si3N4, and MoO3.

[0124] The above inorganic oxide film layer may have a thickness of 10 nm or more and 40 nm or less.

[0125] The apparatus further includes a reduced graphene oxide layer disposed on top of the inorganic oxide layer, wherein the reduced graphene oxide layer may have a thickness of 1 nm or more and 5 nm or less.

[0126] The above reduced graphene oxide layer may be hydrophobic.

[0127] The first electrode and the second electrode may include one or more of Ag, Al, ITO (Indium Tin Oxide), Cu, Mo, and Pt.

[0128] The first electrode and the second electrode may have a width of 5 mm or more and 10 mm or less.

[0129] The first electrode and the second electrode may include a transparent electrode.

[0130] It may further include a power supply unit connected to the first electrode and the second electrode.

[0131] An electric oven according to one example may include a cavity with an open front, having a top plate, a bottom plate, two side plates and a rear plate arranged to face each other, a door for selectively opening and closing the front of the cavity, and a planar heating element disposed on one or more of the top plate, the bottom plate, the two side plates and the rear plate to apply heat to the cavity.

[0132] One or more of the above top plate, above bottom plate, above two side plates and above rear plate may include a transparent substrate.

[0133] One or more of the above top plate, the above bottom plate, the two side plates, and the above rear plate may include one or more of tempered glass, ceramic, and quartz glass.

[0134] It may further include a case arranged to be spaced apart from the top plate, the bottom plate, the two side plates and the rear plate at a predetermined distance.

[0135] The above case may include a transparent substrate.

[0136] It may further include a bezel portion disposed on the above case and disposed in an area corresponding to the first electrode and the second electrode.

[0137] The above case may include one or more of tempered glass, ceramic, and quartz.

[0138] It may further include an insulating member disposed between one or more of the above top plate, above bottom plate, above two side plates and above rear plate and the case.

[0139] The above insulation part may include a transparent material.

[0140] The above insulating member may include one or more of tempered glass, ceramic, and quartz.

[0141] A planar heating element according to one aspect of the present disclosure can improve the adhesion between graphene and an inorganic oxide layer by placing a graphene oxide layer between a graphene layer and an inorganic oxide layer.

[0142] A planar heating element according to one aspect of the present disclosure can prevent the graphene layer from being oxidized by moisture and oxygen, thereby preventing the degradation of heating characteristics.

[0143] A planar heating element according to one aspect of the present disclosure can protect a graphene layer from moisture penetration by disposing of a reduced graphene oxide film layer having hydrophobic properties on the uppermost layer of the planar heating element.

[0144] A planar heating element according to one aspect of the present disclosure can improve ease of manufacturing.

[0145] An electric oven according to one aspect of the present disclosure may have a transparent structure through which visible light can pass from a cavity, which is a cooking space, to a planar heating element, an insulating part, and a case.

[0146] An electric oven according to one aspect of the present disclosure can improve visibility and aesthetic characteristics by being implemented so that the cooking process can be observed from the outside.

[0147] Embodiments of planar heating elements and electric ovens including the same have been described with reference to the drawings for the sake of understanding, but this is merely illustrative and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, various modifications and equivalents are included within the spirit and scope of the present disclosure.

Claims

1. Graphene layer (111); A graphene oxide layer (113) disposed on top of the graphene layer in a first direction; An inorganic oxide layer (115) disposed on top of the graphene oxide layer in the first direction above; A first electrode (150) positioned to be electrically connected to the graphene layer; and It includes a second electrode (160) positioned to be electrically connected to the graphene layer; The graphene layer is disposed between the first electrode and the second electrode, Surface heating element.

2. In Paragraph 1, The thickness of the graphene layer (111) is in the range of 1 nm to 5 nm, and The thickness of the graphene oxide layer (113) is in the range of 0.3 nm to 1 nm, and The thickness of the above inorganic oxide layer (115) is in the range of 10 nm to 40 nm, Surface heating element.

3. In Paragraph 1, The ratio of the thickness of the graphene oxide layer (113) to the thickness of the graphene layer (111) is 3:1 to 5:

1. Surface heating element.

4. In Paragraph 1, The above inorganic oxide film layer (115) comprises one or more of SiO2, TiO2, Si3N4, and MoO3. Surface heating element.

5. In Paragraph 1, It further includes a reduced graphene oxide layer (117) disposed on the upper part of the inorganic oxide layer in the first direction, and The thickness of the above reduced graphene oxide layer (117) is in the range of 1 nm to 5 nm, Surface heating element.

6. In Paragraph 5, The above reduced graphene oxide layer (117) is hydrophobic, Surface heating element.

7. In Paragraph 1, The first electrode (150) and the second electrode (160) comprise one or more of Ag, Al, ITO (Indium Tin Oxide), Cu, Mo, and Pt. Surface heating element.

8. In Paragraph 7, The width of the first electrode and the width of the second electrode are in the range of 5mm to 10mm, Surface heating element.

9. In Paragraph 1, The first electrode and the second electrode include a transparent electrode. Surface heating element.

10. In Paragraph 1, A power supply unit (180) connected to the first electrode (150) and the second electrode (160) further comprising Surface heating element.

11. Top plate (21); A bottom plate (22) positioned to face the upper plate above; First side plate (23); A second side plate (23) positioned to face the first side plate; Rear plate (24); A door (30) configured to selectively open and close the front of a cavity (20) defined by the upper plate, the bottom plate, the first side plate, the second side plate, and the rear plate; and A planar heating element (100) according to any one of claims 1 to 10, disposed on one or more of the upper plate, the bottom plate, the first side plate, the second side plate and the rear plate, and applying heat to the cavity; comprising Electric oven.

12. In Paragraph 11, One or more of the above top plate (21), the above bottom plate (22), the above first side plate (23), the above second side plate (23) and the above rear plate (24) include a transparent substrate. Electric oven.

13. In Paragraph 12, It further includes a case (10) arranged to be spaced apart from the top plate, the bottom plate, the first side plate, the second side plate and the rear plate, and The above case includes a transparent substrate, Electric oven.

14. In Paragraph 13, A bezel portion (16) disposed on the above case and overlapping with the first electrode and the second electrode; further comprising Electric oven.

15. In Paragraph 13, It further includes an insulating portion (50) disposed between one or more of the above top plate, the above bottom plate, the above first side plate, the above second side plate and the above rear plate and the above case, and The above insulation part includes a transparent material, Electric oven.

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