Patent Publication Number: US-2020296801-A1

Title: Material-removing heater device

Description:
This application claims priority to Korean Patent Application No. 10-2019-0027650, filed on Mar. 11, 2019, and all the benefits accruing therefrom under 35 U.S.C. § 119, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Embodiments of the invention relate to a bending device with which a target object is removed from another member. More particularly, embodiments of the invention relate to a material-removing device using a heater of a resistance heating type and with which a film may be uniformly removed from a component of a display device in a chip on panel (“COP”) process during manufacturing of the display device. 
     2. Discussion of the Related Art 
     Display devices may be bendable into a specific form or shape since display panels of the display devices include a relatively soft substrate, instead of a relatively hard substrate, thus having flexibility. A material-removing device using a heater may be used to remove portions of a film provided on the relatively soft substrate of the display panels, such that the film is effectively patterned to maintain other portions of the film on the display panels. 
     SUMMARY 
     Embodiments provide a bending device (e.g., material-removing device) used in manufacturing display devices and capable of uniformly removing portions of a film, by using a heater of a resistance heating type in a chip on panel (COP) process of the display devices. 
     According to an embodiment, a material-removing heater device includes: a first terminal portion defining a first electrode; a second terminal portion defining a second electrode; and a heating portion which connects the first terminal portion to the second terminal portion, the heating portion heatable by a flow of electrical current from the first terminal portion to the second terminal portion to remove a portion of material of a display device. The heating portion defines a lower end surface of the material-removing heater device at which the material-removing heater device contacts the material of the display device, the heating portion disposes the lower end surface to have a concave shape, and the heating portion which is heated deforms the lower end surface from the concave shape to have a planar shape. 
     The heating portion may have a thickness less than a thickness of each of the first terminal portion and the second terminal portion. 
     The heating portion may include a first inner surface and a second inner surface which face each other, the first terminal portion may include an inner surface which faces an inner surface of the second terminal portion, the first inner surface of the heating portion and the inner surface of the first terminal portion may be coplanar with each other, and the second inner surface of the heating portion and the inner surface of the second terminal portion may be coplanar with each other. 
     The first terminal portion, the second terminal portion and the heating portion may together define a first heat dissipation groove of the material-removing heater device at which the first inner surface and the second inner surface of the heating portion face each other. 
     A terminal portion among the first terminal portion and the second terminal portion may define a second heat dissipation groove recessed from an outer surface of the terminal portion and open to outside the material-removing heater device, a first direction may be defined from the heating portion to the terminal portion, and a maximum dimension of the second heat dissipation groove may be extended along the first direction. 
     A second direction crossing the first direction may be defined between ends of the material-removing heater device, and the second heat dissipation groove may be provided in plural including a plurality of second heat dissipation grooves arranged spaced apart from each other along the second direction. 
     The material-removing heater device may define a maximum dimension thereof as a length, a terminal portion among the first terminal portion and the second terminal portion may define a plurality of through holes arranged spaced apart from each other along the length of the material-removing heater device, and each of a through hole among the plurality of through holes may be extended from an outer surface of the terminal portion to an inner surface thereof, the through hole being open to outside the material-removing heater device. 
     A first direction may be defined from the heating portion to the terminal portion, and the through hole may have a circular shape or an elliptical shape which has a major axis along the first direction. 
     The heating portion may further include: a first connection portion extended from the first terminal portion, a second connection portion extended from the second terminal portion and facing the first connection portion, and a third connection portion connecting the first connection portion and the second connection portion to each other, the third connection portion defining the lower end surface of the material-removing heater device. The first connection portion may define a thickness thereof which decreases as a distance from the first terminal portion increases, and the second connection portion may define a thickness thereof which decreases as a distance from the second terminal portion increases. 
     The heating portion which is heated to a temperature of about 300 degrees Celsius (° C.) or more and about 600° C. or less may deform the lower end surface from the concave shape to have the planar shape. 
     The heating portion which is heated may generate a heat having a temperature higher than a temperature at which the material of the display device is melted. 
     The heating portion may extend from both the first terminal portion and the second terminal portion along a first direction, a second direction crossing the first direction may be defined between ends of the material-removing heater device, and the heating portion which is heated may define a maximum deformation distance between the concave shape and the planar shape along the first direction and at a central portion of the material-removing heater device along the second direction. 
     Along the second direction, a length of the lower end surface of the heating portion which has the concave shape may be less than a length of each of the first terminal portion and the second terminal portion. 
     Along the second direction, a length of the lower end surface of the heating portion which has the planar shape may be equal to the length of each of the first terminal portion and the second terminal portion. 
     A material of the heating portion may include Invar, which is an alloy of steel and nickel. 
     A lower end surface of the heating portion may have the concave shape at a temperature of about 25° C., and may have the planar shape at a temperature of about 450° C. 
     The heating portion may have a coefficient of thermal expansion of about 1.3 ppm/° C. at a temperature is about 93° C., about 4.18 ppm/° C. at a temperature is about 260° C., and about 7.6 ppm/° C. at a temperature is about 371° C. 
     The heating portion may have an electrical resistivity in a range from about 0.000070 Ω/cm to about 0.00010 Ω/cm. 
     The heating portion may have a conductivity in a range from about 9.9 W/mK to about 10.5 W/mK. 
     The foregoing is illustrative only and is not intended to be in any way limiting. In addition to the illustrative embodiments and features described above, further embodiments and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention will become more apparent by describing in detail embodiments thereof with reference to the accompanying drawings, where: 
         FIG. 1  is a perspective view illustrating an embodiment of a material-removing device before heating thereof, relative to a film; 
         FIG. 2  is a perspective view illustrating the material-removing device which is heated, relative to the film; 
         FIG. 3  is a perspective view illustrating an embodiment a first inner surface of a heating portion of a material-removing device; 
         FIG. 4  is a perspective view illustrating an embodiment of a second inner surface of the heating portion of the material-removing device; 
         FIG. 5  is a perspective view illustrating an embodiment of a first terminal portion and a second terminal portion of a film removing device; 
         FIG. 6  is a perspective view illustrating another embodiment of a first terminal portion and a second terminal portion of a film removing device; 
         FIG. 7  is a perspective view illustrating a modified embodiment of a first terminal portion and a second terminal portion of a material-removing device; 
         FIG. 8  is a perspective view illustrating another embodiment of a film removing device; 
         FIG. 9  is a cross-sectional view illustrating an embodiment of a film removing device; 
         FIG. 10( a )  is a cross-sectional view illustrating an embodiment of a heating portion before heating thereof and  FIG. 10( b )  is a cross-sectional view of the heating portion which is heated; and 
         FIG. 11  is a cross-view illustrating an embodiment of dimension changes of a heating portion which is heated. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments will now be described more fully hereinafter with reference to the accompanying drawings. Although the invention may be modified in various manners and have several embodiments, embodiments are illustrated in the accompanying drawings and will be mainly described in the specification. However, the scope of the invention is not limited to the embodiments and should be construed as including all the changes, equivalents and substitutions included in the spirit and scope of the invention. Like reference numerals refer to like elements throughout. 
     In the drawings, thicknesses of a plurality of layers and areas are illustrated in an enlarged manner for clarity and ease of description thereof. When a layer, area, or plate is referred to as being related to another element such as being “on” another layer, area, or plate, it may be directly on the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being related to another element such as being “directly on” another layer, area, or plate, intervening layers, areas, or plates are absent therebetween. Further when a layer, area, or plate is referred to as being related to another element such as being “below” another layer, area, or plate, it may be directly below the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being related to another element such as being “directly below” another layer, area, or plate, intervening layers, areas, or plates are absent therebetween. 
     The spatially relative terms “below,” “beneath,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation illustrated in the drawings. For example, in the case where a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction and thus the spatially relative terms may be interpreted differently depending on the orientations. 
     Throughout the specification, when an element is referred to as being “connected” to another element, the element is “directly connected” to the other element (e.g., physical and/or mechanical contacted), or “electrically connected” to the other element with at least one intervening elements interposed therebetween. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly indicates otherwise. “At least one” is not to be construed as limiting “a” or “an.” “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of at least one other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that, although the terms “first,” “second,” “third,” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Accordingly, “a first element” discussed below could be termed “a second element” or “a third element,” and “a second element” and “a third element” may be termed likewise without departing from the teachings herein. 
     “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” may mean within at least one standard deviations, or within ±30%, 20%, 10% or 5% of the stated value. 
     Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this invention pertains. 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 ideal or excessively formal sense unless clearly defined at the present specification. 
     Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims. 
     A manufacturing process of a display device, such as a flexible display device including a display panel having a relatively soft or flexible substrate, may include a chip on panel (“COP”) process in which portions of a film are removed from the display panel. A heater of a resistance heating type may be used to remove the portions of the film. 
     In a conventional manufacturing process, removal a film using a material-removing device (e.g., otherwise referred to herein as a “bending device”) having a heater of a resistance heating type disposes a bottom surface of the material-removing device in a planar state before heating. After heating of the material-removing device, the bottom surface of the heater is convexly curved due to a thermal expansion characteristic thereof. Processes are performed to the display panel of the display device in a state that the bottom surface of the material-removing device contacting the display panel is in the convexly-curved shape. However, processing of the display panel by the material-removing device having the bottom surface in the convex shape contacting the display panel may provide a non-uniform flatness in an area of the display panel which is processed by the material-removing device. 
     Hereinafter, a material-removing device (e.g., a bending device  100 ) will be described with reference to  FIGS. 1 to 11 . 
       FIG. 1  is a perspective view illustrating an embodiment of a bending device  100  before heating, relative to a film  101  which is processable by the bending device  100  while being disposed on a member M, and  FIG. 2  is a perspective view illustrating an embodiment of a bending device  100  after heating, relative to the film  101  which is processable by the bending device  100  while being disposed on the member M. 
     Referring to  FIGS. 1 and 2 , a bending device  100  for a display device includes a first terminal portion  110 , a second terminal portion  120 , and a heating portion  130 . The first terminal portion  110  and the second terminal portion  120  may extend from the heating portion  130 , along a first direction D 1 . The bending device  100  may lengthwise extend along a second direction D 2  crossing the first direction D 1 . 
     The first terminal portion  110  serves as a first electrode (+), and the second terminal portion  120  serves as a second electrode (−). In an alternative embodiment, the first terminal portion  110  may serve as the second electrode (−), and the second terminal portion  120  may serve as the first electrode (+). Of course, the first electrode may be a negative electrode, and the second electrode may be a positive electrode. 
     The first terminal portion  110  and the second terminal portion  120  may be spaced apart from each other by a predetermined distance with planar surfaces thereof facing each other. The first terminal portion  110  and the second terminal portion  120  may be spaced apart from each other along a third direction D 3  crossing each of the first direction D 1  and the second direction D 2 . The first direction D 1 , the second direction D 2  and the third direction D 3  may be respectively perpendicular to each other, without being limited thereto. 
     Each of the first terminal portion  110  and the second terminal portion  120  has a rectangular parallelepiped shape and has a predetermined length extended along the second direction D 2 . The first terminal portion  110  and the second terminal portion  120  have a substantially same length along the second direction D 2 . In an embodiment, the first terminal portion  110  and the second terminal portion  120  may have different lengths. 
     The first terminal portion  110  and the second terminal portion  120  have a substantially same thickness. In an alternative embodiment, the first terminal portion  110  and the second terminal portion  120  may have different thicknesses. The first terminal portion  110  and the second terminal portion  120  each have a thickness which is greater than a thickness of the heating portion  130 . 
     Referring to  FIG. 1 , for example, a thickness of the heating portion is taken along the first direction D 1  and/or the third direction D 3 , while a thickness of the first terminal portion  110  and the second terminal portion  120  is taken along the third direction D 3 . In an embodiment, each of the first terminal portion  110 , the second terminal portion  120  and the heating portion  130  may define a major surface (e.g., the largest planar surface), and a respective thickness of the various portions may be taken in a direction normal to the major surface thereof, without being limited thereto. In an embodiment a respective thickness of the first terminal portion  110 , the second terminal portion  120  and the heating portion  130  may be defined as a minimum dimension thereof along the direction normal to the major surface thereof, without being limited thereto. 
     The heating portion  130  may be connected to the first terminal portion  110  and the second terminal portion  120 . That is, one side (e.g., a first side) of the heating portion  130  may be connected to the first terminal portion  110 , and another side thereof (e.g., a second side opposite to the first side) may be connected to the second terminal portion  120 . That is, the heating portion  130  may connect the first terminal portion  110  and the second terminal portion  120  to each other. The heating portion  130  may connect the first terminal portion  110  and the second terminal portion  120  to each other along an entirety of the length of the bending device  100 , without being limited thereto. 
     Power applied to the bending device  100  from outside thereof, provides a flow of electrical current through the heating portion  130 , from the first terminal portion  110  to the second terminal portion  120 , and heat is generated in the heating portion  130  due to electrical resistance relative to the electrical current. That is, the heating portion  130  is heatable by a flow of electrical current from the first terminal portion  110  to the second terminal portion  120  such as to remove a portion of material of a display device. 
     A lower end surface of the heating portion  130  is defined furthest from the first terminal portion  110  and the second terminal portion  120  along the first direction D 1 . The lower end surface is a surface at which the bending device  100  contacts a material for removal thereof. Referring to  FIG. 1 , before heating, the lower end surface of the heating portion  130  has a concave shape which extends recessed along the first direction D 1  from a plane defined by the second direction D 2  and the third direction D 3  (e.g., solid line compared to the dotted line in  FIG. 1 ). Referring to  FIG. 2 , after heating, the lower end surface of the heating portion  130  has a planar shape. The lower end surface of the heating portion  130  may be disposed in the plane defined by the second direction D 2  and the third direction D 3 , without being limited thereto (e.g., solid line compared to the dotted line in  FIG. 2 ). That is, the lower end surface of the heating portion  130  may be bendable or deformable between the concave shape and the planar shape. 
     In an embodiment, for example, the lower end surface of the heating portion  130  has a concave shape recessed along the first direction D 1  when a temperature is about 25 degrees Celsius (° C.) before heating, and has a planar shape when a temperature is about 40° C. after heating. 
     The heating portion  130  may include a metal material. In an embodiment, for example, the heating portion  130  may include Invar, which is an alloy of steel and nickel. 
     In such a case, for example, a coefficient of thermal expansion (“CTE”) of the heating portion  130  after heating is about 1.3 parts per million per degree Celsius (ppm/° C.) when the temperature is about 93° C., about 4.18 ppm/° C. when the temperature is about 260° C., and about 7.6 ppm/° C. when the temperature is about 371° C. 
     The heating portion  130  may have an electrical resistivity in a range from about 0.000070 ohm per centimeter (Ω/cm) to about 0.00010 Ω/cm. In an embodiment, for example, the heating portion  130  has an electrical resistivity of about 0.000082 Ω/cm. 
     A density of the heating portion  130  is, for example, about 8.05 grams per cubic centimeter (g/cc). 
     The heating portion  130  may have a conductivity in a range from about 9.9 watt/meter/K (W/mK) to about 10.5 W/mK. In an embodiment, for example, the heating portion  130  has a thermal conductivity of about 10.15 W/mK. 
     The heating portion  130  may have a modulus of, for example, about 148 gigapascals (GPa). 
     The heating portion  130  has a thickness less than a thickness of each of the first terminal portion  110  and the second terminal portion  120 . That is, the first terminal portion  110  has a thickness greater than the thickness of the heating portion  130 , and the second terminal portion  120  has a thickness greater than the thickness of the heating portion  130 . In such an embodiment, the first terminal portion  110  and the second terminal portion  120  may have a substantially same thickness, and may each have a thickness at least greater than the thickness of the heating portion  130 . 
     Since the heating portion  130  has the thickness less than the thickness of each of the first terminal portion  110  and the second terminal portion  120 , heat may be generated due to electrical resistivity, faster in the heating portion  130  than in the first terminal portion  110  and/or the second terminal portion  120 . In addition, heat of a higher temperature may be generated in the heating portion  130  than a temperature of heat generated in the first terminal portion  110  and/or the second terminal portion  120 . 
       FIG. 3  is a perspective view illustrating an embodiment of a first inner surface  131  of the heating portion  130 , and  FIG. 4  is a perspective view illustrating an embodiment of a second inner surface  132  of the heating portion  130 . 
     A boundary between the heating portion  130  and the first terminal portion  110  may be defined along the first direction D 1 , at a location where a thickness taken along the third direction D 3  is different to respectively define the heating portion  130  and the first terminal portion  110 . As illustrated in  FIG. 3 , a first inner surface  131  of the heating portion  130  and an inner surface of the first terminal portion  110  are in a substantially same plane (e.g., coplanar with each other to form a single inner surface of the bending device  100 ). 
     A boundary between the heating portion  130  and the second terminal portion  120  may be defined along the first direction D 1 , at a location where a thickness taken along the third direction D 3  is different to respectively define the heating portion  130  and the second terminal portion  120  (e.g., dotted line boundary in  FIG. 8 ). As illustrated in  FIG. 4 , a second inner surface  132  of the heating portion  130  and an inner surface of the first terminal portion  110  are in a substantially same plane (e.g., coplanar with each other to form a single inner surface of the bending device  100 ). 
     Accordingly, the bending device  100  defines a first heat dissipation groove  140  by the first terminal portion  110 , the second terminal portion  120 , and the heating portion  130 . That is, the first inner surface  131  of the heating portion  130  extends from the inner surface of the first terminal portion  110  and is located in a plane substantially the same as a plane on which the inner surface of the first terminal portion  110  is located, and the second inner surface  132  of the heating portion  130  extends from an inner surface of the second terminal portion  120  and is in a plane substantially the same as a plane on which the inner surface of the second terminal portion  120  is located, thereby defining the first heat dissipation groove  140  between the first terminal portion  110  and the second terminal portion  120 . The first heat dissipation groove  140  is defined between two of the single inner surfaces of the bending device  100 , together with an inner surface of the heating portion  130 . The first heat dissipation groove  140  extends from between the first terminal portion  110  and the second terminal portion  120  to between the first inner surface  131  and the second inner surface  132 . The first heat dissipation groove  140  is open along the first direction D 1 . The first heat dissipation groove  140  may also be open along the second direction D 2  (e.g., at one or more end of the bending device  100 ). 
       FIG. 5  is a perspective view illustrating an embodiment of a first terminal portion  110  and a second terminal portion  120  of a bending device  100 . 
     Referring to  FIG. 5 , the first terminal portion  110  includes or defines a second heat dissipation groove  151  which is open to outside the bending device  100  along the first direction D 1  and/or the third direction D 3 . The second heat dissipation groove  151  may be provided in plural (e.g., second heat dissipation grooves  151 ) arranged along a length of the bending device  100  (e.g., along the second direction D 2 ). A length of the second heat dissipation groove  151 , as a maximum dimension thereof, is defined along the first direction D 1 , while a width of the second heat dissipation groove  151  is defined along the second direction D 2  and a depth of the second heat dissipation groove  151  is defined along the third direction D 3 . 
     The second terminal portion  120  includes or defines a second heat dissipation groove  152  which is open to outside the bending device  100  along the first direction D 1  and/or the third direction D 3 . The second heat dissipation groove  152  may be provided in plural (e.g., second heat dissipation grooves  152 ) arranged along the length of the bending device  100  (e.g., along the second direction D 2 ). A length of the second heat dissipation groove  152 , as a maximum dimension thereof, is defined along the first direction D 1 , while a width of the second heat dissipation groove  152  is defined along the second direction D 2  and a depth of the second heat dissipation groove  152  is defined along the third direction D 3 . That is, the second heat dissipation groove  151  and/or the second heat dissipation groove  152  has a dimension (e.g., length) along the first direction D 1  that is greater than a dimension (e.g., width) thereof along the second direction D 2 . 
     The second heat dissipation grooves  151  and the second heat dissipation grooves  152  may be arranged at a predetermined interval along the second direction D 2 . 
     In an embodiment, for example, the first terminal portion  110  may have the second heat dissipation grooves  151  each in a shape of a rectangular parallelepiped shape which is open at an outer side surface of the first terminal portion  110 , arranged at a predetermined interval in the second direction D 2 . The second heat dissipation groove  151  has a predetermined depth, and when heat is generated in the first terminal portion  110  due to electrical resistivity, the second heat dissipation groove  151  compensates for expansion of a material within a limited length of the first terminal portion  110 . 
     In such a case, each individual one of the second heat dissipation grooves  151 , located at a predetermined interval along the second direction D 2  at the outer side surface of the first terminal portion  110 , may be defined having a predetermined width, and having a length along the first direction D 1  that is substantially the same as a length of the first terminal portion  110  along the first direction D 1  at location other than the second heat dissipation groove  151 . That is, each of the second heat dissipation grooves  151  is defined extended along the first direction D 1  that crosses the second direction D 2  which is a length direction of the first terminal portion  110 . Accordingly, even if material of the first terminal portion  110  expands in the second direction D 2  due to heat, the second heat dissipation groove  151  accommodates the extended length of the material of the first terminal portion  110 , thereby substantially reducing or effectively preventing an overall length of the first terminal portion  110  from increasing due to heat. 
     In addition, the second terminal portion  120  may have the second heat dissipation grooves  152  each in a shape of a rectangular parallelepiped shape which is open at an outer side surface of the second terminal portion  120 , arranged at a predetermined interval along the second direction D 2 . The second heat dissipation groove  152  has a predetermined depth, and when heat is generated in the second terminal portion  120  due to electrical resistivity, the second heat dissipation groove  152  compensates for expansion of a material within a limited length of the second terminal portion  120 . 
     In such a case, each individual one of the second heat dissipation groove  152 , located at a predetermined interval along the second direction D 2  at the outer side surface of the second terminal portion  120 , may be defined having a predetermined width, and having a length along the first direction D 1  that is substantially the same as a length of the second terminal portion  120  along the first direction D 1  at location other than the second heat dissipation groove  152 . That is, each of the second heat dissipation grooves  152  is defined extended along the first direction D 1  that crosses the second direction D 2  which is a length direction of the second terminal portion  120 . Accordingly, even if material of the second terminal portion  120  expands along the second direction D 2  due to heat, the second heat dissipation groove  152  accommodates the extended length of the material of the second terminal portion  120 , thereby substantially reducing or effectively preventing an overall length of the second terminal portion  120  from increasing. 
       FIG. 6  is a perspective view illustrating another embodiment of a first terminal portion  110  and a second terminal portion  120  of a bending device  100 . 
     Referring to  FIG. 6 , the first terminal portion  110  and the second terminal portion  120  may include or define a first through hole  160 . The first through hole  160  may be provided in plural (e.g., first through holes  160 ) arranged at a predetermined interval along the second direction D 2 . 
     The first through hole  160  has a circular cross-sectional shape. 
     In addition, the first through hole  160  may extend from the inner side surface of the first terminal portion  110  to the outer side surface thereof which opposes the inner side surface along a third direction D 3 . The first through hole  160  may extend completely through a thickness of the first terminal portion  110 , from the outer surface thereof to the first heat dissipation groove  140 . The first through hole  160  may be open at both the outer side surface of the first terminal portion  110  and at the inner side surface thereof. That is, the first terminal portion  110  may include or define one or more of the first through hole  160  defined therethrough, extending from an outer side surface of the first terminal portion  110  to an inner side surface thereof which opposes the outer side surface along the third direction D 3 , provided or arranged at a predetermined interval along the second direction D 2 . The first through hole  160  passes through a thickness of the first terminal portion  110 , with a depth of the first through hole  160  corresponding to a total thickness of the first terminal portion  110 . When heat is generated in the first terminal portion  110  by electrical resistivity, the first through hole  160  accommodates material of the first terminal portion  110  which is extended by the heat of the first terminal portion  110 . Accordingly, the first terminal portion  110  may have a temperature change due to generation of heat, but the overall length thereof does not change with the temperature change. 
     In addition, the first through hole  160  may extend from an inner side surface of the second terminal portion  120  to an outer side surface thereof which opposes the inner side surface along a third direction D 3 . The first through hole  160  may extend completely through a thickness of the second terminal portion  120 , from the outer surface thereof to the first heat dissipation groove  140 . The first through hole  160  may be open at both the outer side surface of the second terminal portion  120  and at the inner side surface thereof. That is, the second terminal portion  120  may include or define one or more of the first through hole  160 , extending from an inner side surface of the second terminal portion  120  to an outer side surface thereof which opposes the inner side surface along in the third direction D 3 , provided or arranged at a predetermined interval along the second direction D 2 . The first through hole  160  passes through a thickness of the second terminal portion  120 , with a depth of the first through hole  160  corresponding to a total thickness of the second terminal portion  120 . When heat is generated in the second terminal portion  120  by electrical resistivity, the first through hole  160  accommodates the material of the first terminal portion  110  which is extended by the heat of the second terminal portion  120 . Accordingly, the second terminal portion  120  may have a temperature change due to generation of heat, but the overall length thereof does not change with the temperature change. 
     An initial overall length (e.g., before heat or no heat applied) of the first terminal portion  110  and the second terminal portion  120  is defined by material of a respective terminal portion between ends thereof along the second direction D 2 . However, when heat is generated due to electrical resistivity, material of the first terminal portion  110  and the second terminal portion  120  extends along the second direction D 2  and into an area of the through holes  160  due to the heat. However, an overall length of each of the first terminal portion  110  and the second terminal portion  120  along the second direction D 2  (e.g., between ends) does not change owing to the material extending into the through holes  160 . That is, the first terminal portion  110  and the second terminal portion  120  may have a structure capable of better accommodating such change in length along the second direction D 2 . 
     To further enhance this effect, the at least one through hole may have an oval shape, as illustrated in  FIG. 7 .  FIG. 7  is a perspective view illustrating a modified embodiment of a first terminal portion  110  and a second terminal portion  120 . As illustrated in  FIG. 7 , the first terminal portion  110  and the second terminal portion  120  may include or define a second through hole  170 . The second through hole  170  may be provided in plural (e.g., second through holes  170 ) arranged at regular intervals along the second direction D 2 . In such a case, the second through hole  170  may have an oval shape with a major axis along the first direction D 1  and a minor axis along the second direction D 2  to better accommodate the change in length of the bending device  100  along the second direction D 2 . 
     Accordingly, when heat is generated due to electrical resistivity, the first terminal portion  110  and the second terminal portion  120  are subject to a deformation force greater in the second direction D 2  (e.g., the minor axis of the second through hole  170 ) than the first direction D 1  (e.g., the major axis of the second through hole  170 ), thus extending a length of material of the bending device  100  along the second direction D 2  due to heat. The extended length of the material of the first terminal portion  110  and the second terminal portion  120  is accommodated through the plurality of second through holes  170 . 
     Accordingly, a change in overall length (e.g., between ends) along the second direction D 2  due to the temperature change does not occur in the first terminal portion  110  and the second terminal portion  120  due to one or more of the second through hole  170 . 
       FIG. 8  is a perspective view illustrating another embodiment of a bending device  100 . 
     Referring to  FIG. 8 , the heating portion  130  may include a first connection portion  133  and a second connection portion  134 . The heating portion  130  may further include a third connection portion which connects the first connection portion  133  and the second connection portion  134  to each other. The third connection portion is defined furthest from the first terminal portion  110  and the second terminal portion  120  along the first direction D 1 . The third connection portion defines the lower end surface of the heating portion  130  discussed above. 
     The first connection portion  133  extends from the first terminal portion  110  to be located between the first terminal portion  110  and the third connection portion of the heating portion  130 . A thickness of the first connection portion  133  along the third direction D 3  decreases as a distance from the first terminal portion  110  increases (e.g., in a direction toward the third connection portion of the heating portion  130 ). 
     The second connection portion  134  extends from the second terminal portion  120  to be located between the second terminal portion  120  and the third connection portion of the heating portion  130 . A thickness of the second connection portion  134  along the third direction D 3  decreases as a distance from the second terminal portion  120  increases (e.g., in a direction toward the third connection portion of the heating portion  130 ). 
     That is, in the heating portion  130  connected to the first terminal portion  110  and the second terminal portion  120 , the first connection portion  133  and the second connection portion  134  have a shape in which thicknesses of the first connection portion  133  and the second connection portion  134  in the third direction D 3  are gradually reduced in a direction towards the third connection portion along the first direction D 1 . 
     Referring to  FIG. 8 , the lower end surface of the heating portion  130  at the third connection portion thereof, forms an obtuse angle with an outer surface of both the first connection portion  133  and the second connection portion  134 . Referring to  FIG. 4 , for example, the lower end surface of the heating portion  130  at the third connection portion thereof, forms less than an obtuse angle with outer surfaces which respectively oppose the first inner surface  131  and the second inner surface  132 . An angle less than the obtuse angle may include an angle of about 90° without being limited thereto. A thickness of the heating portion  130  at the first inner surface  131  and the second inner surface  132  in  FIG. 4  may be uniform as a distance from a respective terminal portion increases along the first direction D 1 , without being limited thereto. 
       FIG. 9  is a cross-sectional view illustrating an embodiment of a bending device  100 , viewed in a third direction D 3 . 
     Referring to  FIG. 9 , together with  FIG. 5 , for example, when the bending device  100  is viewed in the third direction D 3 , the first terminal portion  110  is located at an upper portion, and the heating portion  130  is located at a lower portion. 
     At the first terminal portion  110 , one or more second heat dissipation grooves  151  are arranged at regular intervals along the second direction D 2 . 
     The heating portion  130  may have a predetermined length along the second direction D 2 . In an embodiment, the heating portion  130  has a length of, for example, about 70 millimeters (mm). 
     The heating portion  130  may generate heat of a temperature higher than a temperature at which a material of an object to be processed (e.g., film  101  in  FIGS. 1 and 2  is deformed or melted by the heating portion  130  which is heated). 
     The heating portion  130  may be deformed due to thermal expansion at a temperature of about 300° C. or more and about 600° C. or less. 
     When the heating portion  130  includes Invar, the heating portion  130  may have an electrical resistivity in a range from about 0.000070 Ω/cm to about 0.00010 Ω/cm. In an embodiment, for example, the heating portion  130  has an electrical resistivity of about 0.000082 Ω/cm. 
     In the bending device  100 , when power is applied from the outside the bending device  100  and through the first terminal portion  110 , an electrical current flows through the heating portion  130 , from the first terminal portion  110  to the second terminal portion  120 . 
     In such a case, a Joule heat (b) is generated according to electrical energy (power), and the heating portion  130  converts the Joule heat (b) into a dissipation heat (a) based on electrical resistivity, thus discharging the dissipation heat (a), as in the following Equation 1. Accordingly, a sum of the Joule heat (b) and an amount of the dissipation heat (a) becomes zero. 
     
       
         
           
             
               
                 
                   
                     
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     In Equation 1, (a) represents the dissipation heat generated due to the electrical resistivity in the heating portion  130 , and (b) represents the Joule heat generated due to the electrical energy of the first terminal portion  110  and the second terminal portion  120 . 
     Each of the first terminal portion  110  and the second terminal portion  120  has a predetermined length, for example, about 70 mm, along the second direction D 2 . Although thermal expansion occurs in the material of the first terminal portion  110  and the second terminal portion  120  due to the Joule heat generated due to the electrical energy, the second heat dissipation grooves  151  and  152  accommodate the length of the material which is extended due to thermal expansion, such that opposing ends of the a respective terminal portion are not displaced. Accordingly, the total length (e.g., between ends) of the first terminal portion  110  and the second terminal portion  120  may not exceed about 70 mm although thermal expansion of the material within the respective terminal portion occurs, due to the second heat dissipation grooves  151  and  152  at which the extended material is accommodated. That is, even though a temperature changes due to heat generation, a physical change in the total length of the first terminal portion  110  and the second terminal portion  120  (e.g., between ends) does not occur. 
     A temperature of the heating portion  130  increases as heat is generated due to the electrical resistivity. When the temperature rises, a thermal stress is generated as illustrated in the following Equation 2, and accordingly, thermal expansion occurs and the material of the heating portion  130  extends. 
       Equation 2 
       ∇·σ=0  (c)
 
       σ= E (ε−α( T−T   amb ) I )  (d)
 
     In Equation 2, ∇ represents a gradient, σ represents a thermal stress, E represents an elastic modulus, ε represents a strain, α represents a coefficient of thermal expansion, T represents a temperature of the heating portion, T amb  represents an ambient temperature, and I represents a deformation amount according to the length of the heating portion. 
     That is, the thermal stress σ is calculated by multiplying the elastic modulus E by the strain c and the deformation amount I. In such a case, the strain ε is a strain based on coefficient of thermal expansion α and a temperature change T−T amb . 
       FIG. 10( a )  is a cross-sectional view illustrating an embodiment of a heating portion  130  which is un-heated (e.g., before heating),  FIG. 10( b )  is a cross-sectional view of the heating portion  130  which is heated, and  FIG. 11  is a cross-sectional view illustrating an embodiment of dimension changes of a heating portion  130 . 
     As illustrated in the view  FIG. 10( a ) , a lower end surface of the heating portion  130  has a shape that is concave (solid line in  FIG. 10( a ) ) along the first direction D 1  before heating of the bending device  100 . As illustrated in  FIG. 10( b ) , the lower end surface of the heating portion  130  is displaced from the concave shape to be disposed a planar shape (solid line in  FIG. 10( b ) ) by heat application to the bending device  100 , due to thermal expansion.  FIG. 11  is a cross-sectional view of an embodiment of displacement of end portions of the heating portion  130 . 
     Since the heating portion  130  has a thickness less than the thickness of each of the first terminal portion  110  and the second terminal portion  120 , heat is generated faster in the heating portion  130  than in the first terminal portion  110  and the second terminal portion  120 , and the temperature of the generated heat rises faster in the heating portion  130  than in the first terminal portion  110  and the second terminal portion  120 . 
     Taking  FIGS. 1, 2 and 9-11  together, for example, one or more embodiment of the bending device  100  including a heater of a resistance heating type disposes a bottom surface of the bending device  100  in a planar state after heating of the bending device  100 . 
     In an embodiment of manufacturing a display device, processes are performed to a member M (e.g., a display panel of the display device) having a film  101  thereon, by the bending device  100  having the lower end surface which is planar. More particularly, the lower end surface of the bending device  100  has a planar area with a relatively short width in the third direction D 3  and a length along the second direction D 2 , to contact the film  101  to be processed. Accordingly, portions of the film  101  which are contacted by the bending device  100  may be removed from the member M while minimizing or effectively preventing deformation of a relatively soft portion of the member M (e.g., flexible substrate of a display panel) such that a display panel of a display device provided using the bending device  100  has a uniform flatness even at areas which are processed with the bending device  100 . 
     The heating portion  130  may include a material that may withstand temperatures of about 600° C. or less. 
     In addition, the heating portion  130  may be deformed due to thermal expansion at a temperature of about 300° C. or more and about 600° C. or less. 
     That is, heat is generated in the heating portion  130  due to electrical resistivity. The heat is relatively easily conducted in the heating portion  130  as the temperature thereof rises since the heating portion  130  has a thickness less than a thickness of each of the first terminal portion  110  and the second terminal portion  120 , such that a material of the heating portion  130  expands and extends as the temperature rises. In embodiments, a material of the heating portion  130  extends with the coefficient of thermal expansion of about 1.3 ppm/° C. at a temperature of about 93° C., with the coefficient of thermal expansion of about 4.18 ppm/° C. at a temperature of about 260° C., and with the coefficient of thermal expansion of about 7.6 ppm/° C. at a temperature of about 371° C. 
     Accordingly, as illustrated in  FIG. 10( a ) , the lower end surface of the heating portion  130  has a shape that is concave in a positive (+) first direction D 1  before heating. After heating, however, the temperature of the heating portion  130  rises, and the lower end surface of the heating portion  130  expands, by a distance H in a negative (−) first direction D 1 , due to thermal expansion, and becomes planar as illustrated in  FIG. 10( b ) . 
     The distance H at which the heating portion  130  is deformed, from a concave shape before heating to a planar shape after heating may be maximum along the first direction D 1 , at a center portion of the heating portion  130  which is taken along the second direction D 2 . That is, a dimension of the heating portion  130  along the first direction D 1  may be defined between the lower end surface furthest from a respective terminal portion, to a boundary between the heating portion  130  and the respective terminal portion. The dimension of the heating portion  130  along the first direction D 1  may increase by the extension of the lower end surface a concave shape to a planar shape after heating. In an embodiment, the increased dimension (e.g., distance H) taken at the center portion of the heating portion  130  which is defined along the second direction D 2  may about 21 micrometers (μm) along the first direction D 1 . 
     The heating portion  130  may generate heat having a temperature higher than a temperature at which a material of an object to be processed is melted. In an embodiment of manufacturing a display device, a film  101  (e.g., protective film as an object to be processed) may be attached to a member M (e.g., display panel having a relatively soft flexible substrate) prior to further processing the display panel for forming a display device. In an embodiment, for example, in order to remove a portion or an entirety of the protective film attached to the display panel, the heating portion  130  may generate a heat having a temperature higher than a melting temperature of the protective film, e.g., higher than about 465° C. 
     Referring to  FIG. 11 , before heating, a distance between opposite ends of the heating portion  130  along the second direction D 2  may be less than the length of each of the first terminal portion  110  and the second terminal portion  120 . 
     A distance between opposite ends of the heating portion  130  along the second direction D 2  may be substantially equal to or less than the length of each of the first terminal portion  110  and the second terminal portion  120  after heating. Each end portion may move a length (a) along the second direction D 2  to be disposed substantially corresponding to ends of each of the first terminal portion  110  and the second terminal portion  120  after heating. Each end portion may move a length (b) along the first direction D 1  to define the lower end surface of the heating portion  130  having a planar shape after heating. 
     Opposing ends of the heating portion  130 , when viewed along the third direction D 3 , may extend, after heating, by a length calculated by a vector sum (c) of a length (b) extending along the first direction D 1  and a length (a) extending along the second direction D 2 . 
     Referring to  FIG. 11 , for example, each of lower corners of the heating portion  130  which are on opposite sides thereof extend, after heating, by about 102 μm in a negative (−) first direction D 1  than before heating (e.g., b=102 μm). A right lower corner portion extends, after heating, by about 92 μm in a negative (−) second direction D 2  than before heating (e.g., a=92 μm), and a left lower corner portion extends, after heating, by about 92 μm in a positive (+) second direction D 2  than before heating (e.g., a=92 μm). 
     In such an embodiment, along the second direction D 2 , the lower end surface of the heating portion  130  is planarized after heating, from a shape that is concave in the positive (+) first direction D 1  before heating, and thus the heating portion extends by a distance H of about 21 μm in the negative (−) first direction D 1 . 
     In addition, the lower corners of the heating portion  130  which are on the opposite sides thereof extend, after heating, in the negative (−) first direction D 1  by about 102 μm, and both extend, after heating, along the second direction D 2  by about 92 μm, thus extending in a diagonal direction (c) by about 137.3 μm. 
     Accordingly, although opposing corners extend respectively along the first direction D 1  and the second direction D 2  due to thermal expansion of the heating portion  130  after heating, a length of the heating portion  130  which is thermally expanded may not exceed the length of about 70 mm discussed above, and the lower end surface of the heating portion  130  becomes planarized, such that a portion or an entirety of the protective film may be uniformly removed from the display panel across an entirety of the length of the bending device  100 . 
     One or more embodiment of a bending device  100  may be used in manufacturing display devices. More particularly, one or more embodiment of the bending device  100  may uniformly remove a portion or an entirety of a film  101  from another member M of the display device, such as in a chip on plate (“COP”) process of the display device, by using a heater of a resistance heating type. 
     Accordingly, a member such as a display panel of a display device which has a uniform flatness may be manufactured through thermal processing while patterning a film on the display panel. 
     While the invention has been illustrated and described with reference to the embodiments thereof, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made thereto without departing from the spirit and scope of the invention.