CUP HOLDER

According to one embodiment, a cup holder is disclosed. The cup holder comprises: a holder body; a thermoelectric element disposed at a lower part of the holder body; a heat sink disposed at a lower part of the thermoelectric element; and a fan disposed on a side surface of the holder body, and discharging, through the heat sink, air suctioned from the side surface of the holder body.

TECHNICAL FIELD

The present invention relates to a cup holder, and more specifically, to a heating and cooling cup holder.

BACKGROUND ART

A cup holder mounted in a particular location such as a vehicle or the like can only serve to fix a cup to prevent spillage of the contents put in the cup due to movement and cannot heat or cool the contents put in a cup, a can, or the like.

Although a cup holder capable of performing heating and cooling has been developed to solve the problem of the cup holder, a cooling mode and a heating mode cannot be simultaneously performed.

Further, a cup holder using a thermoelectric element has been developed, but has a large volume due to a shape in which a fan is in contact with the thermoelectric element and a heat sink attached to the thermoelectric element. In addition, since a flow path space through which air introduced through the fan flows is large, the cup holder is difficult to compactly manufacture.

DISCLOSURE

Technical Problem

The present invention is directed to providing a hot and cold cup holder using a thermoelectric element.

Technical Solution

A cup holder according to an embodiment of the present invention includes a holder body, a thermoelectric element disposed under the holder body, a heat sink disposed under the thermoelectric element, and a fan disposed at a side surface of the holder body and configured to discharge air suctioned from the side surface of the holder body through the heat sink.

The heat sink may include a plurality of fins disposed to be spaced apart from each other in a direction the same as a direction in which the air is discharged.

The plurality of fins may be disposed in parallel.

The cup holder may further include a guide part including a first member disposed between the holder body and the heat sink and including a hole and a second member disposed between the holder body and the fan and including an air flow path configured to guide the suctioned air.

The thermoelectric element may be disposed in the hole.

The air flow path may be formed such that the suctioned air passes toward the heat sink.

The fan may discharge the air in a direction different from a direction in which the air is suctioned.

The fan may include a blower fan.

The cup holder may further include a housing configured to surround outer surfaces of the heat sink and the fan.

The housing may include a suction port into which the air is suctioned from the fan and a discharge port through which the suctioned air is discharged.

The discharge port may be disposed to be adjacent to the heat sink.

The holder body may be made of a thermal conductive metal material.

The cup holder may further include a power module configured to supply power to the fan and the thermoelectric element.

The power module may be controlled so that the thermoelectric element may perform one of heating and cooling of the holder body.

The cup holder may further include a switch connected to the power module to transmit a control signal of one of the heating and the cooling of the holder body to the power module.

Advantageous Effects

A cup holder according to an embodiment of the present invention can provide a heating and cooling function to a container configured to contain beverages using a heat absorption function or a heat generation function of a thermoelectric element. Particularly, the thermoelectric element can be disposed under the cup holder to uniformly provide the heating and cooling function to the whole parts of the container in the cup holder.

Further, a cup holder capable of easily receiving power regardless of a place and thus having improved portability and convenience can be provided.

In addition, a direction in which air flows in the cup holder and a structure of a heat sink attached to the thermoelectric element can correspond to each other to allow heat-exchange to occur efficiently, a cup holder having a slim structure can be implemented by varying disposition locations of the thermoelectric element and a fan, and space efficiency in the cup holder can be improved.

MODES OF THE INVENTION

Since the present invention may be variously changed and have various embodiments, particular embodiments will be exemplified in the drawings and described. However, the present invention is not limited to the particular embodiment and includes all changes, equivalents, and substitutes falling within the spirit and the scope of the present invention.

Further, it should be understood that, although the terms “first,” “second,” and the like may be used herein to describe various elements, the elements are not limited by the terms. The terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element without departing from the scope of the present invention. The term “and/or” includes combinations of one or all of a plurality of associated listed items.

When predetermined components are mentioned to be “linked,” “coupled,” or “connected” to other components, the components may be directly linked or connected to other components, but it should be understood that additional components may be “linked,” “coupled,” or “connected” therebetween. However, when the predetermined components are mentioned to be “linked,” “coupled,” or “connected” to other components, it should be understood that no additional components exist between the above-described components.

Terms used in the present invention are used solely to describe the particular embodiments and not to limit the present invention. The singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It should be further understood that the terms “include,” “including,” “have,” and/or “having” specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms including technical or scientific terms used in the present invention have meanings the same as those of terms generally understood by those skilled in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings, the same reference numerals are applied to the same or corresponding components regardless of the drawing numerals, and overlapping descriptions will be omitted.

FIG. 1is a view illustrating a cup holder according to an embodiment of the present invention, andFIG. 2is an exploded perspective view of the cup holder according to the embodiment of the present invention.

In the embodiment, a cup holder10may accommodate a container therein and provide a heating and cooling function to the accommodated container, and includes a holder body100, a thermoelectric element200, a heat sink300, a fan400, a guide part500, a power module600, a housing700, a switch800, and a connection part900.

The holder body100has a center part having a hollow shape and includes an accommodation part therein. Further, a cup used for a user for drinking or a container configured to accommodate liquid, such as beverages or the like, may be mounted in the accommodation part. In addition, the holder body100may include a metal material, an alloy material, and a synthetic resin material having great heat transference efficiency so that heating and cooling effects may be provided to the cup mounted in the holder body100or beverages.

In addition, the holder body100may have a cylindrical structure having curvature, and a lower part of the holder body100may have a flat plate-shaped area the thermoelectric element200may be mounted.

The thermoelectric element200may be provided under the holder body100, and a heat generation part or a heat absorption part of the thermoelectric element200may be disposed to be in contact with a lower surface of the holder body100. Thermal grease may be provided between the thermoelectric element200and the lower part of the holder body100to improve the characteristics of thermoelectric efficiency.

In the thermoelectric element200, a part in which the thermoelectric element200and the lower surface of the holder body100are in contact with each other may become the heat generation part or the heat absorption part according to polarity of power supplied to the thermoelectric element200. Accordingly, both the cooling effect and the heat generation effect may be provided to the container accommodated in the holder body100.

Further, when the thermoelectric element200, which is a heat source, is disposed on a side surface of the holder body100, the heat source is difficult to transfer to a part distant from a part at which the thermoelectric element200is disposed. According to the embodiment of the present invention, since the thermoelectric element200is provided under the holder body100, the heat source generated from the thermoelectric element200may be uniformly provided to the whole parts of the holder body100. Further, when heat generation is performed at the lower surface of the holder body100, heat transference to the liquid in the container accommodated in the holder body100is further improved in terms of heat convection.

In addition, a structure of the thermoelectric element200or the like may be described with reference to the following,FIG. 7.

The heat sink300is provided on a lower surface of the thermoelectric element200and exchanges heat transferred from the thermoelectric element200with surrounding air. The heat sink300is disposed to be spaced apart from a flat base and includes a plurality of protruding fins310.

The plurality of fins310include a metal material having excellent heat conduction and heat dissipation properties and, as one embodiment, include an aluminum material. Further, the plurality of fins310may be disposed to be spaced from each other to form predetermined intervals. In addition, the plurality of fins310may be disposed in parallel.

Air may flow between the plurality of fins310which are disposed in parallel in the heat sink300, and a flow path, through which the air flows, may be formed in a direction which is the same as a direction in which the air is discharged. Accordingly, the air is smoothly moved in the heat sink300, and heat-exchange is performed efficiently.

The fan400is provided on a side surface of the holder body100to perform suction and discharge of the air and promote the heat-exchange in the heat sink300. That is, the air may be suctioned from one surface of the holder body100due to the suction and discharge of the air from the fan400, and the suctioned air may be discharged to the lower part of the holder body100through the heat sink300of the cup holder10. Accordingly, the fan400serves to induce the air to the heat sink300and allow the air to circulate in an apparatus.

Referring toFIG. 3, which is a cross-sectional view of the cup holder according to the embodiment of the present invention and an enlarged view of the heat sink, the air, which is introduced through the fan400provided on the side surface of the holder body100in the cup holder10, flows to the lower surface of the holder body100on which the heat sink300is disposed and is discharged to a discharge port O formed in another side surface of the holder body100along spaces formed between the plurality of fins310due to continuously introduced air.

Further, since the fan400and the thermoelectric element200(including the heat sink300) have different disposition locations, the entire size of the cup holder10may be reduced more than that in a case in which the thermoelectric element200and the fan400are integrally disposed to be in close contact with each other. Accordingly, the cup holder10according to the embodiment may be compactly manufactured.

Referring toFIG. 6, which is a view illustrating the various fans according to the embodiment of the present invention, an air suction direction and an air discharge direction of a fan400-1may be the same (seeFIG. 6A). Further, an air suction direction and an air discharge direction of a fan400-2may be different and may form a predetermined angle (seeFIG. 6B).

Referring toFIG. 6B, the fan may be a blower fan400-2, and the air suction direction and the air discharge direction at the fan400-2may be perpendicular to each other. Accordingly, the air suctioned from the side surface of the holder body100may be directly discharged to a lower part of the cup holder at which the heat sink is located. Accordingly, since air which collides with the holder body100is decreased, backflow of the air may be prevented, and since the suctioned air is smoothly discharged to the discharge port, heat-exchange promotion through the heat sink300may be improved.

The guide part500is provided to guide the suctioned air to the heat sink300through the fan400and support the holder body100, and includes a first member510and a second member520.

The first member510is disposed between the holder body100and the heat sink300and includes a hole h. The thermoelectric element200is disposed in the hole h so that the first member510surrounds the thermoelectric element200. Accordingly, the first member supports the holder body100and prevents transference of the air suctioned from the outside through the air fan400to the holder body100. Accordingly, thermal equilibrium of the holder body100may be prevented by the air suctioned from the outside.

The second member520includes an air flow path disposed between the holder body100and the fan400and configured to guide the air suctioned from the fan400to the heat sink300.

The second member520may be disposed on the side surface of the holder body100and formed to surround the side surface of the holder body100to prevent transference of the air introduced from the fan400to the holder body100.

Further, the second member520is formed to guide a flow path of the air so that the air suctioned from the fan400flows to the heat sink300. As one embodiment, the second member520may be formed to be inclined toward the heat sink300.

Further, the second member520may form an accommodation part on which the fan400may be mounted and may be formed to change an air flow so that the suctioned air may flow to the heat sink300under the cup holder10. For example, the fan400may be formed so that an air suction direction and an air discharge direction may be different. Accordingly, the thermal equilibrium of the holder body100may be prevented by the air suctioned from the outside through the second member520. Further, since the air suctioned through the fan400flows through the heat sink300without leakage to the outside and a flow of the air becomes smooth, efficient heat-exchange may be performed in the heat sink300.

In addition, the second member520may be located on an end portion or one end of the first member510, and the first member510and the second member520may be an integrally coupled shape.

The power module600is provided to supply the power to the thermoelectric element200and the fan400, and may control polarity of the power supplied to the thermoelectric element200to heat or cool the holder body100. Further, as one embodiment, an electric wire connected between the power module600and one of an external power and the switch800may be two electric wires. Further, the power module600may be connected to each of the fan400and the thermoelectric element200through two electric wires. In addition, the power module600may be disposed at the inside or the outside of the cup holder10. In addition, although the power module is exemplified to be disposed at the inside of the cup holder10, the present invention is not limited thereto.

The housing700is an outer surface of the cup holder10configured to surround the holder body100, the thermoelectric element200, the heat sink300, the fan400, the guide part500, and the power module600. Referring toFIGS. 4 and 5, a suction port I through which the air is suctioned is formed in a side surface of the housing700. The suction port I is formed to correspond to the location of the fan400disposed in the housing700and the air suction direction so as to smoothly suction the air. As one embodiment, the suction port I may include a plurality of holes and be formed to have an area the same as that of the fan400.

Further, the discharge port O is formed in one side surface of the holder body100in a direction in which the air flows through the plurality of fins310, and, accordingly, the air may be smoothly discharged to the outside. In addition, as one embodiment, the discharge port O may include a plurality of holes, and the plurality of holes may be formed in various shapes.

As one embodiment, the discharge port O may be formed to correspond to a shape between the plurality of fins310of the heat sink300through which the air flows.

Further, the housing700is disposed at the outer surface of the cup holder10so that the air introduced into the suction port I flows through the heat sink300, and the housing700surrounds and seals the holder body100, the fan400, the thermoelectric element200, and the heat sink300so that the air is discharged to only the suction port I and the discharge port.

In addition, an electric wire hole P connected to the power may be formed in one side surface of the housing700.

The switch800may be connected to the power module600and disposed at the inside or the outside of the cup holder10. In addition, the switch800may transmit a control signal to the power module600according to a selection of the user to heat or cool the holder body100.

The connection part900is a connection part900connected to the external power and may have various shapes. As one embodiment, the connection part900may be formed as Universal Serial Bus (USB) power to easily supply power at any place.

As described above, the cup holder may be provided at various places or spots such as a chair of a vehicle or a theater, an accommodation space for beverages at a council board of a conference room, and the like. Further, since the cup holder may be provided as a separably detachable structure to improve user convenience and may be formed to be coupled to containers having various sizes, a conventional cup holder may be easily mounted. In addition, since an insertion diameter of the container is implemented to be variable, versatility may be demonstrated.

Referring toFIG. 7, which is a cross-sectional view of the thermoelectric element according to the embodiment of the present invention, andFIG. 8, which is a perspective view of the thermoelectric element according to the embodiment of the present invention, the thermoelectric element200includes a lower substrate210, a lower electrode220, a P-type thermoelectric leg230, an N-type thermoelectric leg240, an upper electrode250, and an upper substrate260.

A thermoelectric phenomenon is a phenomenon which occurs due to movement of an electron and a hole in a material and refers to direct energy conversion between heat and electricity.

The thermoelectric element is a general term for elements using the thermoelectric phenomenon and has a structure in which a P-type thermoelectric material and an N-type thermoelectric material are bonded between metal electrodes to form a PN junction pair.

The thermoelectric element may be classified into an element using temperature variation of an electric resistance, an element using a Seebeck effect, which is a phenomenon in which an electromotive force is generated due to a temperature difference, an element using a Peltier effect, which is a phenomenon in which heat absorption or heat generation due to a current occurs, or the like.

The lower electrode220is disposed between the lower substrate210and lower bottom surfaces of the P-type thermoelectric leg230and the N-type thermoelectric leg240, and the upper electrode250is disposed between the upper substrate260and upper bottom surfaces of the P-type thermoelectric leg230and the N-type thermoelectric leg240. Accordingly, a plurality of P-type thermoelectric legs230and a plurality of N-type thermoelectric legs240are electrically connected to each other by the lower electrode220and the upper electrode250. A pair of P-type thermoelectric leg230and N-type thermoelectric leg240disposed between the lower electrode220and the upper electrode250and electrically connected to each other may form a unit cell.

For example, when a voltage is applied to the lower electrode220and the upper electrode250through lead wires281and282, due to the Peltier effect, a substrate in which a current flows from the P-type thermoelectric leg230to the N-type thermoelectric leg240may absorb heat and serve as a cooling part, and a substrate in which a current flows from the N-type thermoelectric leg240to the P-type thermoelectric leg230may be heated and serve as a heat generation part.

Here, the P-type thermoelectric leg230and the N-type thermoelectric leg240may be formed of bismuth telluride (Bi-Te)-based thermoelectric legs including bismuth (Bi) and tellurium (Ti) as main materials. The P-type thermoelectric leg 230 may be a thermoelectric leg including 99 to 99.999 wt % of a bismuth telluride (Bi-Te)-based main material including at least one of stibium (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te), bismuth (Bi), and indium (In), and 0.001 to 1 wt % of a compound including Bi or Te on the basis of the total weight 100 wt %. For example, the P-type thermoelectric leg 230 may include Bi-Se-Te as a main material and may further include Bi or Te in an amount of 0.001 to 1 wt % of the total weight. The N-type thermoelectric leg 240 may be a thermoelectric leg including 99 to 99.999 wt % of a bismuth telluride (Bi-Te) main material including at least one of selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te), bismuth (Bi), and indium (In), and 0.001 to 1 wt % of a compound including Bi or Te on the basis of the total weight 100 wt %. For example, the N-type thermoelectric leg240may include Bi-Sb-Te as a main material, and may further include Bi or Te in an amount of 0.001 to 1 wt % of the total weight.

Each of the P-type thermoelectric leg230and the N-type thermoelectric leg240may be formed as a bulk type or a lamination type. Generally, the bulk type P-type thermoelectric leg230or the bulk type N-type thermoelectric leg240may be acquired through a process of heat-treating a thermoelectric material to manufacture an ingot, acquiring a powder for the thermoelectric leg by grinding and straining the ingot, and then sintering the powder and cutting a sintered body. The lamination type P-type thermoelectric leg230or the lamination type N-type thermoelectric leg240may be acquired through a process of forming a unit member by applying paste including a thermoelectric material on a sheet-shaped base material, and then laminating and cutting the unit member.

In this case, a pair of thermoelectric legs including the P-type thermoelectric leg230and N-type thermoelectric leg240may have the same shape and volume, or different shapes and volumes. For example, since conductive characteristics of the P-type thermoelectric leg230and the N-type thermoelectric leg240are different, a height or cross-sectional area of the N-type thermoelectric leg240may be formed to be different from that of the P-type thermoelectric leg230.

The performance of the thermoelectric element according to the embodiment of the present invention may be shown as a Seebeck index. The Seebeck index (ZT) may be expressed by Equation 1.

Here, α is a Seebeck coefficient [V/K], σ is electrical conductivity [S/m], and α2σ is a power factor, [W/mK2]). Further, T is a temperature, and k is thermal conductivity [W/mK].

k may be expressed as a·cp·ρ, a is thermal diffusivity [cm2/S], cpis specific heat [J/gK], and ρ is density [g/cm3].

In order to acquire the Seebeck index of the thermoelectric element, a Z value (V/K) may be measured using a Z meter, and the Seebeck index (ZT) may be calculated using the measured Z value.

Here, each of the lower electrode220, which is disposed between the lower substrate210and the P-type thermoelectric leg230and the N-type thermoelectric leg240, and the upper electrode250, which is disposed between the upper substrate260and the P-type thermoelectric leg230and the N-type thermoelectric leg240, may include at least one of copper (Cu), silver (Ag), and nickel (Ni) and have a thickness of 0.01 mm to 0.3 mm. When the thickness of the lower electrode220or the upper electrode250is smaller than 0.01 mm, a function thereof as an electrode may be lowered and thus an electricity conductivity performance may be lowered, and when the thickness is greater than 0.3 mm, a resistance may increase and thus conductivity efficiency may be lowered.

Further, the lower substrate210and the upper substrate260which face each other may be insulating substrates or metal substrates. The insulating substrate may be an alumina substrate or a flexible polymer resin substrate. The flexible polymer resin substrate may include various insulating resin materials such as polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copolymer (COC), polyethylene terephthalate (PET), high transmissive plastic such as resin, and the like. The metal substrate may include Cu, a Cu alloy, or a Cu-Al alloy and may have a thickness of 0.1 mm to 0.5 mm. When the thickness of the metal substrate is smaller than 0.1 mm or greater than 0.5 mm, since a heat dissipation characteristic or thermal conductivity may excessively increase, reliability of the thermoelectric element may be lowered. Further, when the lower substrate210and the upper substrate260are the metal substrates, dielectric layers270may be further formed between the lower substrate210and the lower electrode220and between the upper substrate260and the upper electrode250. The dielectric layer270includes a material having a heat conductivity of 5˜10 W/K and may be formed to have a thickness of 0.01 mm to 0.15 mm. When the thickness of the dielectric layer270is smaller than 0.01 mm, insulation efficiency or a withstand voltage characteristic may be lowered, and when the thickness is greater than 0.15 mm, the thermoelectric conductivity is lowered and thus heat dissipation efficiency may be lowered.

In this case, the lower substrate210and the upper substrate260may be different sizes. For example, a volume, a thickness, or an area of one of the lower substrate210and the upper substrate260may be formed to be greater than that of the other one. Accordingly, heat absorption performance or heat dissipation performance of the thermoelectric element may be improved.

Further, a heat dissipation pattern, for example, an uneven pattern, may be formed in a surface of at least one of the lower substrate210and the upper substrate260. Accordingly, the heat dissipation performance of the thermoelectric element may be improved. When the uneven pattern is formed in a surface which is in contact with the P-type thermoelectric leg230or the N-type thermoelectric leg240, the junction characteristics between the thermoelectric leg and the substrate may be improved.

FIG. 9is a view illustrating a method of manufacturing thermoelectric legs having a lamination structure. Referring toFIG. 9, a material including a semiconductor material is manufactured in a paste type and then applied on a base material1110such as a sheet, a film, or the like to form a semiconductor layer1120. Accordingly, one unit member1100may be formed.

A plurality of unit members1100a,1100b,and1100cmay be laminated to form a lamination structure1200, and a unit thermoelectric leg1300may be acquired by cutting the lamination structure1200.

Like the above, the unit thermoelectric leg1300may be formed by a structure in which the plurality of unit members1100, each having the semiconductor layer1120formed on the base material1110, are laminated.

Here, the process of applying the paste on the base material1110may be performed by various methods. For example, the process of applying the paste on the base material1110may be performed by a tape casting method. The tape casting method is a method of mixing a fine semiconductor powder with at least one of an aqueous or nonaqueous solvent, a binder, a plasticizer, a dispersant, a defoamer, and a surfactant to manufacture in a slurry type and then molding on a moving blade or a moving base material. In this case, the base material1110may be a film, a sheet, or the like having a thickness of 10 um to 100 um, and the P-type thermoelectric material or the N-type thermoelectric material which manufactures the above-described bulk-type element may be applied, intact, as a semiconductor material which is applied.

A process of aligning and laminating the unit member1100as a plurality of layers may be performed by a method of pressing at a temperature of 50 to 250° C., and the number of laminated unit members1100, may be, for example, two to fifty. Further, the unit member1100may be cut in a desired shape and a desired size, and a sintering process may be added.

Like the above, the manufactured unit thermoelectric leg1300may secure uniformity of a thickness, a shape, and a size thereof, may be advantageous for being thinned, and may reduce loss of a material.

The unit thermoelectric leg1300may have a cylindrical shape, a polygonal pillar shape, an ellipse pillar shape, or the like, and may be cut in a shape shown inFIG. 9D.

Meanwhile, a conductive layer may be further formed on one surface of the unit member1100to manufacture the thermoelectric leg having a lamination structure.

FIGS. 10 to 12are conceptual diagrams of the heat sink according to the embodiment of the present invention. Referring toFIGS. 10 to 12, the heat sink300according to the embodiment of the present invention is a flat plate-shaped base material having a first flat surface311and a second flat surface312and may include at least one flow path pattern312A configured to form an air flow path C1.

As shown inFIGS. 10 to 12, the flow path pattern312A may be formed in a structure which folds the base material, that is, a folded structure, to form a curvature pattern having predetermined pitches P1and P2and a predetermined thickness T1.

Like the above, the air may be in surface contact with the first flat surface311and the second flat surface312of the heat sink300, and a surface with which the air comes into contact by the flow path pattern312A may be maximized.

Referring toFIG. 10, when the air is introduced in a flow path direction C1, the air may uniformly come into contact with the first flat surface311and the second flat surface312and move to proceed in a flow path direction C2. Accordingly, since the heat sink300has a surface area which comes into contact with the air greater than that of a flat plate-shaped base material, an effect of heat absorption or heat generation increases.

According to the embodiment of the present invention, a protruding resistance pattern313may be formed on a surface of the base material to further increase an air contact area.

Further, as shown inFIG. 11, the resistance pattern313may be formed as a protruding structure inclined to have a predetermined inclination angle θ in a direction in which the air is introduced. Accordingly, since friction between the resistance pattern313and the air may be maximized, a contact area or contact efficiency may increase. Further, grooves314may be formed in a base material surface of a front portion of the resistance pattern313. Since some of the air which comes into contact with the resistance pattern313moves between a front surface and a rear surface of the base material by passing through the grooves314, the contact area or the contact efficiency may further increase.

The resistance pattern313is shown to be formed in the first flat surface311but is not limited thereto and may also be formed in the second flat surface312.

Referring toFIG. 12, the flow path pattern may have various modifications.

For example, patterns having curvature at a predetermined pitch P1may be repetitively formed as shown inFIG. 12A, patterns having sharp parts may be repetitively formed as shown inFIG. 12B, and the unit pattern may have a polygonal structure as shown inFIGS. 12C and 12D. Although not shown, the resistance pattern may also be formed in surfaces B1and B2of the pattern.

The flow path pattern has a predetermined period and a predetermined height inFIG. 12, but the present invention is not limited thereto, and the period and the height T1of the flow path pattern may be nonuniformly changed.

Although the present invention is described in the above with reference to a preferable embodiment of the present invention, the present invention may be understood to be variously changed and modified by those skilled within the spirit and the scope of the present invention disclosed in the below-described claims.