Patent Publication Number: US-11641756-B2

Title: Display device with enhanced damage resistance and method for manufacturing the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional of copending U.S. patent application Ser. No. 15/824,681, filed on Nov. 28, 2017, which claims priority under 35 U.S.C. § 119(a) to Korean Patent Application No. 10-2016-0180912 filed on Dec. 28, 2016, all of these applications are hereby expressly incorporated by reference into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a display device and a method for manufacturing the same. 
     Discussion of the Related Art 
     With the advancement of the information age, a demand for a display device for displaying an image has been increased in various forms. Therefore, various display devices such as liquid crystal display (LCD) devices, plasma display panel (PDP) devices, and organic light emitting display (OLED) devices have been used. 
     Among the display devices, the organic light emitting display device is a self-light emitting device, and has advantages in that a viewing angle and a contrast ratio are more excellent than those of the liquid crystal display device. Also, since the organic light emitting display device does not require a separate backlight, it is advantages that the organic light emitting display device is able to be thin and lightweight and has low power consumption. Furthermore, the organic light emitting display device has advantages in that it may be driven at a low direct current voltage, has a fast response speed, and especially has a low manufacturing cost. 
     The organic light emitting display device includes pixels, each of which includes an organic light emitting diode, and a bank partitioning the pixels to define the pixels. The bank may serve as a pixel definition film. The organic light emitting diode includes an anode electrode, a hole transporting layer, an organic light emitting layer, an electron transporting layer, and a cathode electrode. In this case, if a high potential voltage is applied to the anode electrode and a low potential voltage is applied to the cathode electrode, holes and electrons are moved to the organic light emitting layer through the hole transporting layer and the electron transporting layer, respectively, and are combined with each other in the organic light emitting layer to emit light. 
     The organic light emitting diode has a problem in that the organic light emitting diode is likely to be degraded due to external factors such as external H 2 O and O 2 . To prevent such a problem from occurring, the organic light emitting device includes an encapsulation film formed to prevent external H 2 O and O 2  from being permeated into the organic light emitting diode. 
       FIG.  1    is a cross-sectional view briefly illustrating a display device of a related art. 
     Referring to  FIG.  1   , in the display device of the related art, an encapsulation layer  30  is formed on a substrate  10  provided with an organic light emitting diode layer  20 . At this time, the encapsulation layer  30  prevents O 2  or H 2 O from being permeated into the organic light emitting layer  20  and an electrode. 
     It is general that processes for manufacturing a display device are not performed continuously. For example, the organic light emitting diode layer  20  and the encapsulation layer  30  may be formed on the first substrate  10  through a continuous process. Then, the substrate  10  provided with the organic light emitting diode layer  20  and the encapsulation layer  30  may move to perform a later process. At this time, to prevent the organic light emitting diode layer  20  and the encapsulation layer  30  from being damaged, the first substrate  10  moves to a place where a later process is performed in a state that a protective film  40  is attached thereto as shown in  FIG.  1   . Then, the later process is performed after the protective film  40  is removed from the first substrate  10 . 
     The protective film  40  includes a substrate layer  42  and an adhesive layer  44 . The adhesive layer  44  is deposited on the entire surface of the substrate layer  42  to cover an entire surface of the encapsulation layer  30 . At this time, the adhesion between the encapsulation layer  30  and the adhesive layer  44  is greater than that between an organic light emitting layer of the organic light emitting diode layer  20  and the cathode electrode, a problem occurs in that the cathode electrode is separated from the organic light emitting layer when the protective film  40  is removed from the first substrate  10 . Since light is not emitted normally in an area where the cathode electrode is separated from the organic light emitting layer, a defect of the display device occurs. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a display device and a method for manufacturing the same, which substantially obviate one or more problems due to limitations and disadvantages of the related art. 
     An advantage of the present invention is to provide a display device and a method for manufacturing the same, in which a cathode electrode is not separated from an organic light emitting layer. 
     Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method for manufacturing a display device according to one embodiment of the present invention comprises the steps of forming pixels on a display area on a first substrate; forming an encapsulation film to cover the display area; attaching a protective film onto the encapsulation film; and removing the protective film. At this time, the protective film includes a substrate layer and a first adhesive layer formed at an edge area of at least one side of the substrate layer. 
     In another aspect of the present invention, a display device according to another embodiment of the present invention comprises a substrate including a display area on which pixels are arranged, and a non-display area surrounding the display area; and a protective film adhered onto the substrate. At this time, the protective film includes a substrate layer and a first adhesive layer formed at an edge area of at least one side of the substrate layer. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG.  1    is a cross-sectional view briefly illustrating a display device of the related art; 
         FIG.  2    is a perspective view illustrating a display device according to one embodiment of the present invention; 
         FIG.  3    is a plane view illustrating a first substrate, a source drive IC, a flexible film, a circuit board, and a timing controller of  FIG.  2   ; 
         FIG.  4    is a cross-sectional view briefly illustrating a first substrate according to a first embodiment of the present invention; 
         FIG.  5    is a plane view briefly illustrating a first substrate according to the first embodiment of the present invention; 
         FIG.  6    is a cross-sectional view illustrating an example of a pixel of a display area of  FIG.  5   , taken along line I-I′ in  FIG.  5   ; 
         FIG.  7    is a cross-sectional view taken along line II-II′ shown in  FIG.  5   ; 
         FIG.  8    is a cross-sectional view taken along line III-III′ shown in  FIG.  5   ; 
         FIG.  9    is a plane view illustrating a modified embodiment of  FIG.  5   ; 
         FIG.  10    is a plane view illustrating another modified embodiment of  FIG.  5   ; 
         FIG.  11    is a cross-sectional view briefly illustrating a first substrate according to a second embodiment of the present invention; 
         FIG.  12    is a plane view briefly illustrating a first substrate according to the second embodiment of the present invention; 
         FIG.  13    is a cross-sectional view taken along line IV-IV′ shown in  FIG.  12   ; 
         FIG.  14    is a plane view illustrating a modified embodiment of  FIG.  12   ; 
         FIG.  15    is a flow chart illustrating a method for manufacturing a display device according to the first embodiment of the present invention; and 
         FIGS.  16 A to  16 E  are cross-sectional views illustrating a method for manufacturing a display device according to the first embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Advantages and features of the present invention, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Further, the present invention is only defined by scopes of claims. 
     A shape, a size, a ratio, an angle, and a number disclosed in the drawings for describing embodiments of the present invention are merely an example, and thus, the present invention is not limited to the illustrated details. Like reference numerals refer to like elements throughout the specification. In the following description, when the detailed description of the relevant known function or configuration is determined to unnecessarily obscure the important point of the present invention, the detailed description will be omitted. 
     In a case where ‘comprise’, ‘have’, and ‘include’ described in the present specification are used, another part may be added unless ‘only˜’ is used. The terms of a singular form may include plural forms unless referred to the contrary. 
     In construing an element, the element is construed as including an error range although there is no explicit description. 
     In describing a position relationship, for example, when the position relationship is described as ‘upon˜’, ‘above˜’, ‘below˜’, and ‘next to˜’, one or more portions may be arranged between two other portions unless ‘just’ or ‘direct’ is used. 
     In describing a time relationship, for example, when the temporal order is described as ‘after˜’, ‘subsequent˜’, ‘next˜’, and ‘before˜’, a case which is not continuous may be included unless ‘just’ or ‘direct’ is used. 
     It will be understood that, although the terms “first”, “second”, etc. 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. 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. 
     Further, “X-axis direction”, “Y-axis direction” and “Z-axis direction” should not be construed by a geometric relation only of a mutual vertical relation, and may have broader directionality within the range that elements of the present invention may act functionally. 
     The term “at least one” should be understood as including any and all combinations of one or more of the associated listed items. For example, the meaning of “at least one of a first item, a second item, and a third item” denotes the combination of all items proposed from two or more of the first item, the second item, and the third item as well as the first item, the second item, or the third item. Also the term “may” fully encompasses all the meanings of the term “can”. 
     Features of various embodiments of the present invention may be partially or overall coupled to or combined with each other, and may be variously inter-operated with each other and driven technically as those skilled in the art can sufficiently understand. The embodiments of the present invention may be carried out independently from each other, or may be carried out together in co-dependent relationship. 
     Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG.  2    is a perspective view illustrating a display device  100  according to one embodiment of the present invention, and  FIG.  3    is a plane view illustrating a first substrate, a source drive IC, a flexible film, a circuit board, and a timing controller of  FIG.  2   . Hereinafter, the display device according to one embodiment of the present invention, which will be described, is, but not limited to, an organic light emitting display device. That is, the display device according to one embodiment of the present invention may be realized as any one of a liquid crystal display device, a field emission display device and an electrophoresis display device. Further all components of the display device according to all embodiments of the present invention are operatively coupled and configured. 
     Referring to  FIGS.  2  and  3   , the display device  100  according to one embodiment of the present invention includes a display panel  110 , a source drive integrated circuit (IC)  140 , a flexible film  150 , a circuit board  160 , and a timing controller  170 . 
     The display panel  110  includes a first substrate  111  and a second substrate  112 . The second substrate  112  may be an encapsulation substrate. The first substrate  111  may be a plastic film or a glass substrate. The second substrate  112  may be a plastic film, a glass substrate, or an encapsulation film. 
     Gate lines, data lines and pixels are formed on one surface of the first substrate  111 , which faces the second substrate  112 . The pixels are provided in an area defined by a crossing structure of the gate lines and the data lines. 
     Each of the pixels may include an organic light emitting diode that includes a thin film transistor, a first electrode, an organic light emitting layer, and a second electrode. Each of the pixels supplies a predetermined current to the organic light emitting diode in accordance with a data voltage of the data line if a gate signal is input from the gate line by using the thin film transistor. For this reason, the organic light emitting diode of each of the pixels may emit light with a predetermined brightness in accordance with the predetermined current. A structure of each of the pixels will be described later with reference to  FIGS.  5  and  6   . 
     The display panel  110  may be categorized into a display area DA where the pixels are formed to display an image and a non-display area NDA where an image is not displayed, as shown in  FIG.  3   . The gate lines, the data lines and the pixels may be formed on the display area DA. A gate driver and pads may be formed on the non-display area NDA. 
     The gate driver supplies gate signals to the gate lines in accordance with a gate control signal input from the timing controller  170 . The gate driver  20  may be formed on the non-display area NDA outside one side or both sides of the display area DA of the display panel  110  in a gate driver in panel (GIP) mode. Alternatively, the gate driver may be fabricated of a driving chip, packaged in a flexible film and attached to the non-display area NDA outside one side or both sides of the display panel  110  in a tape automated bonding (TAB) mode. 
     The source drive IC  140  receives digital video data and a source control signal from the timing controller  170 . The source drive IC  140  converts the digital video data to analog data voltages in accordance with the source control signal and supplies the analog data voltages to the data lines. If the source drive IC  140  is fabricated of a driving chip, the source drive IC  140  may be packaged in the flexible film  150  in a chip on film (COF) or chip on plastic (COP) mode. 
     Pads such as data pads may be formed on the non-display area NDA of the display panel  110 . Lines which connect the pads with the source drive IC  140  and lines which connect the pads with lines of the circuit board  160  may be formed in the flexible film  150 . The flexible film  150  may be attached onto the pads by an anisotropic conducting film, whereby the pads may be connected with the lines of the flexible film  150 . 
     The circuit board  160  may be attached to the flexible films  150 . A plurality of circuits comprised of driving chips may be packaged in the circuit board  160 . For example, the timing controller  170  may be packaged in the circuit board  160 . The circuit board  160  may be a printed circuit board or a flexible printed circuit board. 
     The timing controller  170  receives digital video data and a timing signal from an external system board through a cable. The timing controller  170  generates a gate control signal for controlling an operation timing of the gate driver and a source control signal for controlling the source drive ICs  140  on the basis of the timing signal. The timing controller  170  supplies the gate control signal to the gate driver, and supplies the source control signal to the source drive ICs  140 . 
     First Embodiment 
       FIG.  4    is a cross-sectional view briefly illustrating an example of a display device including a first substrate  111  according to the first embodiment of the present invention. 
     The first substrate  111  for moving to a place where a later process is performed before being bonded to a second substrate  112  is shown in  FIG.  4   . The first substrate  111  according to one embodiment of the present invention is provided with a thin film transistor layer  210 , an organic light emitting diode layer  220 , an encapsulation layer  230 , and a protective film  240 , which are formed on one surface. 
     The first substrate  111  may be a plastic film or a glass substrate. 
     The thin film transistor layer  210  is formed on the first substrate  111 . The thin film transistor layer  210  may include scan lines, data lines, and thin film transistors. Each of the thin film transistors includes a gate electrode, a semiconductor layer, and source and drain electrodes. 
     The organic light emitting diode layer  220  is formed on the thin film transistor layer  210 . The organic light emitting diode layer  220  includes first electrodes, organic light emitting layers, second electrodes, and banks. Each of the organic light emitting layers may include a hole transporting layer, an organic light emitting layer, and an electron transporting layer. In this case, if a voltage is applied to each of the second electrode and the first electrode, holes and electrons are moved to the light emitting layer through the hole transporting layer and the electron transporting layer, respectively, and are combined with each other in the light emitting layer to emit light. Since the pixels are provided in the area where the organic light emitting diode layer  220  is formed, the area where the organic light emitting diode layer  220  is formed may be defined as the display area. A peripheral area of the display area may be defined as the non-display area. 
     The encapsulation layer  230  is formed on the organic light emitting diode layer  220 . The encapsulation layer  230  serves to prevent O 2  or H 2 O from being permeated into the organic light emitting diode layer  220 . The encapsulation layer  230  may include at least one inorganic film. 
     A protective film  240  is formed on the encapsulation layer  230 . The protective film  240  includes a substrate layer  242  and an adhesive layer  244 . The protective film  240  serves to prevent particles from being permeated into the thin film transistor layer  210 , the organic light emitting diode layer  220  and the encapsulation layer  230  formed on the first substrate  111  or prevent the thin film transistor layer  210 , the organic light emitting diode layer  220  and the encapsulation layer  230  from being damaged while the first substrate  111  is moving to perform the later process. The protective film  240  is attached onto the encapsulation layer  230  before the first substrate  111  moves to the place where the later process is performed, and then is separated from the encapsulation layer  230  before the later process is performed. 
     Hereinafter, a structure of the protective film  240  according to the first embodiment of the present invention will be described with reference to  FIGS.  5  to  14   . 
       FIG.  5    is a plane view briefly illustrating the first substrate  111  according to the first embodiment of the present invention. 
     Referring to  FIG.  5   , the first substrate  111  is categorized into the display area DA and the non-display area NDA, wherein a pad area PA where pads are formed may be formed on the non-display area NDA. 
     Pixels P for displaying an image are formed on the display area DA. Each of the pixels may include an organic light emitting diode that includes a thin film transistor, a first electrode, an organic light emitting layer, and a second electrode. Each of the pixels supplies a predetermined current to the organic light emitting diode in accordance with the data voltage of the data line if the gate signal is input from the gate line by using the thin film transistor. For this reason, the organic light emitting diode of each of the pixels may emit light with a predetermined brightness in accordance with the predetermined current. 
     Hereinafter, a structure of each of the pixels P of the display area DA according to the embodiments of the present invention will be described in detail with reference to  FIG.  6   . 
       FIG.  6    is a cross-sectional view cut along line I-I′ of  FIG.  5   , for illustrating an example of the pixel of the display area of  FIG.  5   . 
     Referring to  FIG.  6   , the thin film transistor layer  210  is formed on one surface of the first substrate  111 . At this time, the thin film transistor layer  210  includes thin film transistors  310  and capacitors  320 . 
     In more detail, a buffer film may be formed on the first substrate  111  to protect the thin film transistors  310  from H 2 O permeated through the first substrate  111  which is vulnerable to moisture permeability. 
     Each of the thin film transistors  310  includes an active layer  311 , a gate electrode  312 , a source electrode  313 , and a drain electrode  314 . Although the thin film transistors  310  are formed in a top gate mode in such a manner that the gate electrode  312  is arranged above the active layer  311  as shown in  FIG.  6   , it is to be understood that the thin film transistors of the present invention are not limited to the top gate mode. That is, the thin film transistors  310  may be formed in a bottom gate mode in which the gate electrode  312  is arranged below the active layer  311  or a double gate mode in which the gate electrode  312  is arranged above and below the active layer  311 . 
     The active layer  311  is formed on the buffer film of the first substrate  110 . The active layer  311  may be formed of a silicon based semiconductor material or an oxide based semiconductor material. A light-shielding layer for shielding external light entering the active layer  311  may be formed on the first substrate  110 . 
     A gate insulating film  330  may be formed on the active layer  311 . The gate insulating film  330  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     The gate electrode  312  may be formed on the gate insulating film  330 . The gate electrode  312  may be, but not limited to, a single layer or multi-layer comprised of any one of Mo, Al, Cr, Au, Ti, Ni, Nd and Cu or their alloy. 
     An inter-layer dielectric layer  340  may be formed on the gate electrode  312 . The inter-layer dielectric layer  340  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film, or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     The source electrode  313  and the drain electrode  314  may be formed on the inter-layer dielectric layer  340 . Each of the source electrode  313  and the drain electrode  314  may be connected to the active layer  311  through contact holes CH 1  and CH 2  that pass through the gate insulating film  330  and the inter-layer dielectric layer  340 . Each of the source electrode  313  and the drain electrode  314  may be, but not limited to, a single layer or multi-layer comprised of any one of Mo, Al, Cr, Au, Ti, Ni, Nd and Cu or their alloy. 
     Each of the capacitors  320  includes a lower electrode  321  and an upper electrode  322 . The lower electrode  321  is formed on the gate insulating film  330 , and may be formed of the same material as that of the gate electrode  312 . The upper electrode  322  is formed on the inter-layer dielectric layer  340 , and may be formed of the same material as that of the source electrode  313  and the drain electrode  324 . 
     A passivation film  350  may be formed on the thin film transistor  310  and the capacitor  320 . The passivation film  350  may serve as an insulating film. The passivation film  350  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film, or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     The organic light emitting diode layer  220  is formed on the thin film transistor layer  210 . At this time, the organic light emitting diode layer  220  includes an organic light emitting diode  380 . 
     In more detail, a planarization film  360  for planarizing a step difference due to the thin film transistor  310  and the capacitor  320  may be formed on the passivation film  350 . The planarization film  360  may be formed of an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin. 
     The organic light emitting diode  380  and a bank  384  are formed on the planarization film  360 . The organic light emitting diode  380  includes a first electrode  381 , an organic light emitting layer  382 , and a second electrode  383 . The first electrode  381  may be an anode electrode, and the second electrode  383  may be a cathode electrode. An area where the first electrode  381 , the organic light emitting layer  382  and the second electrode  383  are deposited may be defined as an emission area (EA). 
     The first electrode  381  may be formed on the planarization film  360 . The first electrode  381  is connected to the drain electrode  314  of the thin film transistor  310  through a contact hole CH 3  that passes through the passivation film  350  and the planarization film  360 . The first electrode  381  may be formed of a metal material having high reflectivity such as a deposition structure (Ti/Al/Ti) of Al and Ti, a deposition structure (ITO/Al/ITO) of Al and ITO, an APC alloy, and a deposition structure (ITO/APC/ITO) of APC alloy and ITO. The APC alloy is an alloy of Ag, Pd and Cu. 
     The bank  384  may be formed on the planarization film  360  to cover an edge of the first electrode  381 , thereby partitioning the emission areas EA. The bank  384  may be formed of an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin. 
     The organic light emitting layer  382  is formed on the first electrode  381  and the bank  384 . The organic light emitting layer  382  may include a hole transporting layer, at least one light emitting layer, and an electron transporting layer. In this case, if a voltage is applied to the first electrode  381  and the second electrode  383 , holes and electrons are moved to the light emitting layer through the hole transporting layer and the electron transporting layer, respectively, and are combined with each other in the light emitting layer to emit light. 
     The organic light emitting layer  382  may be comprised of a white light emitting layer emitting white light. In this case, the organic light emitting layer  382  may be formed to cover the first electrode  381  and the bank  384 . In this case, a color filter may be formed on the second substrate  112 . 
     Alternatively, the organic light emitting layer  382  may be comprised of a red light emitting layer emitting red light, a green light emitting layer emitting green light, or a blue light emitting layer emitting blue light. In this case, the organic light emitting layer  382  may be formed in an area corresponding to the first electrode  381 , and a color filter may not be formed on the second substrate  112 . 
     The second electrode  383  is formed on the organic light emitting layer  382 . If the organic light emitting display device is formed in a top emission structure, the second electrode  383  may be formed of a transparent conductive material (TCO) such as ITO and IZO, which may transmit light, or a semi-transmissive conductive material such as Mg, Ag, or alloy of Mg and Ag. A capping layer may be formed on the second electrode  383 . 
     An encapsulation layer  230  is formed on the organic light emitting diode layer  220 . At this time, the encapsulation layer  230  includes an encapsulation film  390 . 
     In more detail, the encapsulation film  390  is formed on the organic light emitting diode  380 . The encapsulation film  390  serves to prevent H 2 O or O 2  from being permeated into the organic light emitting layer  382  and the second electrode  383 . To this end, the encapsulation film  390  may include at least one inorganic film and at least one organic film. 
     For example, the encapsulation film  390  may include a first inorganic film  391 , a first organic film  392 , and a second inorganic film  393 . In this case, the first inorganic film  391  is formed to cover the second electrode  383 . The first organic film  392  is formed on the first inorganic film  391 . The first organic film  392  is preferably formed at a sufficient thickness to prevent particles from being permeated into the organic light emitting layer  382  and the second electrode  383  by passing through the first inorganic film  391 . The second inorganic film  393  is formed to cover the first organic film  392 . 
     A protective film  240  is formed on the encapsulation film  390 . The protective film  240  includes a substrate layer  242  and an adhesive layer  244 . The substrate layer  242  is only formed on the encapsulation film  390  arranged in the pixel P. An air gap is formed between the encapsulation film  390  and the substrate layer  242 . Therefore, the encapsulation film  390  and the substrate layer  242  are not adhered to each other in the area where the pixels P are arranged, and their adhesion is close to 0 gf/inch. 
     Referring to  FIG.  5    again, the pad area PA may be arranged at an edge of one side of the first substrate  111 . The pad area PA includes a plurality of pads, which may electrically be connected with lines of the flexible film  150  by using an anisotropic conducting film. 
     The protective film  240  is adhered on the display area DA and the non-display area NDA. At this time, the protective film  240  may not be formed on the pad area PA as shown in  FIG.  5   . However, the present invention is not limited to the example of  FIG.  5   . In another embodiment, the protective film  240  may be formed even on the pad area PA as shown in  FIGS.  9  and  10   . 
     The protective film  240  includes the substrate layer  242  and the adhesive layer  244 . The first embodiment of the present invention is characterized in that the adhesive layer  244  is formed on the edge area of the substrate layer  242  but is not formed at the center area of the substrate layer  242 . 
     Hereinafter, the protective film  240  according to the first embodiment of the present invention will be described in more detail with reference to  FIGS.  7  and  8   . 
       FIG.  7    is a cross-sectional view taken along line II-II′ shown in  FIG.  5   , and  FIG.  8    is a cross-sectional view taken along line III-III′ shown in  FIG.  5   . 
     For convenience of description, detailed elements of the thin film transistor layer  210  will be omitted or may be brief in  FIGS.  7  and  8   , and  FIGS.  7  and  8    illustrate a TFT substrate  300  that the detailed elements of the thin film transistor layer  210 . 
     Referring to  FIGS.  7  and  8   , the organic light emitting diode  380 , the encapsulation film  390  and the protective film  240  are formed on the TFT substrate  300 . 
     The encapsulation film  390  is formed to cover the organic light emitting diode  380  formed on the display area DA, thereby preventing H 2 O and O 2  from being permeated into the organic light emitting diode  380 . At this time, the encapsulation film  390  may include at least one inorganic film and at least one organic film. For example, the encapsulation film  390  may include a first inorganic film  391 , an organic film  392 , and a second inorganic film  393 . In this case, the first inorganic film  391  is formed to cover the second electrode  383 . The organic film  392  is formed on the first inorganic film  391 , and the second inorganic film  393  is formed to cover the organic film  392 . 
     Each of the first and second inorganic films  391  and  393  may be formed of a silicon nitride, an aluminum nitride, a zirconium nitride, a titanium nitride, a hafnium nitride, a tantalum nitride, silicon oxide, an aluminum oxide, or a titanium oxide. The first and second inorganic films  391  and  393  may be deposited by, but not limited to, a chemical vapor deposition (CVD) method or atomic layer deposition (ALD) method. 
     The organic film  392  may be formed transparently to transmit light emitted from the organic light emitting layer  382 . The organic film  392  may be formed of an organic material, which may transmit light emitted from the organic light emitting layer  382  at 95% or more, for example, acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin. The organic film  392  may be formed by, but not limited to, vapor deposition, printing or slit coating method, which uses organic matters. The organic film  392  may be formed by an ink-jet process. 
     The protective film  240  covers the encapsulation film  390  to protect the organic light emitting diode  380  and the encapsulation film  390  formed on the first substrate  111  while the first substrate  111  is moving to the place where the later process is performed. The protective film  240  is formed even on the non-display area NDA as well as the display area DA to cover the encapsulation film  390 , and may not be formed on the pad area PA of the non-display area NDA as shown in  FIG.  8   . 
     The protective film  240  includes the substrate layer  242  and the adhesive layer  244 , and the substrate layer  242  and the encapsulation film  390  are adhered to each other by the adhesive layer  244 . 
     The adhesive layer  244  is formed at the edge area of the substrate layer  242 , and is not formed at the center area of the substrate layer  242 . At this time, the edge area of the substrate layer  242  provided with the adhesive layer  244  is overlapped with the non-display area, and may partially be overlapped with the display area DA. However, even though the adhesive layer  244  is partially overlapped with the display area DA, the adhesive layer  244  is not formed to be overlapped with the second electrode  383  of the organic light emitting diode  380 . In this way, since the adhesive layer  244  is formed at the edge area of the substrate layer  242  but is not formed on the second electrode  383 , the encapsulation film  390  of the area where the second electrode  383  is formed is not adhered with the substrate layer  242 . At this time, since an air gap is formed between the encapsulation film  390  and the substrate layer  242 , adhesion between the encapsulation film  390  and the substrate layer  242  is close to 0 gf/inch. 
     Meanwhile, adhesion between the adhesive layer  244  and the encapsulation film  390  may be greater than that between the second electrode  383  and the organic light emitting layer  382  of the organic light emitting diode  380 . The protective film  240  should not be separated from the first substrate  111  on which the organic light emitting diode  380  and the encapsulation film  390  are formed while the first substrate  111  is moving to the place where the later process is performed. To make sure of it, adhesion between the adhesive layer  244  and the encapsulation film  390  should be greater than that between the second electrode  383  and the organic light emitting layer  382  of the organic light emitting diode  380 . Since the adhesive layer  244  is not overlapped with the second electrode  383 , even though the adhesion between the adhesive layer  244  and the encapsulation film  390  is greater than that between the second electrode  383  and the organic light emitting layer  382 , a gap between the second electrode  383  and the organic light emitting layer  382  is not generated when the protective film  240  is removed. 
     In the first embodiment of the present invention, the adhesive layer  244  is formed at the edge area only of the substrate layer  242  and is formed so as not to be overlapped with the second electrode  383 , whereby the second electrode  383  may be prevented from being separated from the organic light emitting layer  382  when the protective film  240  is removed. 
     Although  FIG.  5    shows that the adhesive layer  244  is overlapped with a part of the display area DA, the present invention is not limited to the example of  FIG.  5   . In another embodiment, the adhesive layer  244  may not be overlapped with the display area DA. For example, if the second electrode  383  is formed to be extended to the non-display area NDA, the adhesive layer  244  may not be overlapped with the display area DA. At this time, the adhesive layer  244  may be formed to be overlapped with a part of the non-display area NDA and at the same time so as not to be overlapped with the second electrode  383 . 
     Although  FIG.  5    shows that the adhesive layer  244  is not formed on the pad area PA, the present invention is not limited to the example of  FIG.  5   . In another embodiment, the adhesive layer  244  may be formed on the non-display area NDA including the pad area as shown in  FIG.  9   . 
     Also, although  FIG.  5    shows that the adhesive layer  244  is formed at four edge areas of the substrate layer  242 , the present invention is not limited to the example of  FIG.  5   . In another embodiment, the adhesive layer  244  may be formed at only two edge areas of the substrate layer  242 , which face each other, as shown in  FIG.  10   . 
     Second Embodiment 
       FIG.  11    is a cross-sectional view briefly illustrating a display device including a first substrate  111  according to the second embodiment of the present invention. 
     The first substrate  111  for moving to a place where a later process is performed before being bonded to a second substrate  112  is shown in  FIG.  11   . Since a thin film transistor layer  210 , an organic light emitting diode layer  220 , and an encapsulation layer  230 , which are shown in  FIG.  11   , are substantially the same as those shown in  FIGS.  5  to  8   , their detailed description will be omitted. 
     A protective film  240  is formed on the encapsulation layer  230 . The protective film  240  includes a substrate layer  242 , a first adhesive layer  244 , and a second adhesive layer  246 . The protective film  240  serves to prevent particles from being permeated into the thin film transistor layer  210 , the organic light emitting diode layer  220  and the encapsulation layer  230  formed on the first substrate  111  or prevent the thin film transistor layer  210 , the organic light emitting diode layer  220  and the encapsulation layer  230  from being damaged while the first substrate  111  is moving to perform the later process. The protective film  240  is attached onto the encapsulation layer  230  before the first substrate  111  moves to the place where the later process is performed, and then separated from the encapsulation layer  230  before the later process is performed. 
     Hereinafter, a structure of the protective film  240  according to the second embodiment of the present invention will be described with reference to  FIGS.  12  to  13   . 
       FIG.  12    is a plane view briefly illustrating a first substrate according to the second embodiment of the present invention. 
     Referring to  FIG.  12   , the first substrate  111  is categorized into a display area DA and a non-display area NDA, wherein a pad area PA where pads are formed may be formed on the non-display area NDA. 
     Pixels P for displaying an image are formed on the display area DA. Each of the pixels may include an organic light emitting diode that includes a thin film transistor, a first electrode, an organic light emitting layer, and a second electrode. Each of the pixels supplies a predetermined current to the organic light emitting diode in accordance with the data voltage of the data line if the gate signal is input from the gate line by using the thin film transistor. For this reason, the organic light emitting diode of each of the pixels may emit light with a predetermined brightness in accordance with the predetermined current. 
     The pad area PA may be arranged at an edge of one side of the first substrate  111 . The pad area PA includes a plurality of pads, which may electrically be connected with lines of the flexible film  150  by using an anisotropic conducting film. 
     The protective film  240  is adhered on the display area DA and the non-display area NDA. At this time, the protective film  240  may not be formed on the pad area PA as shown in  FIG.  12   . However, the present invention is not limited to the example of  FIG.  12   . In another embodiment, the protective film  240  may be formed even on the pad area PA. 
     The protective film  240  includes a substrate layer  242 , a first adhesive layer  244  and a second adhesive layer  246 . The second embodiment of the present invention is characterized in that the first adhesive layer  244  is formed on the edge area of the substrate layer  242  and the second adhesive layer  246  is formed at the center area of the substrate layer  242 . 
     Hereinafter, the protective film  240  according to the second embodiment of the present invention will be described in more detail with reference to  FIG.  13   . 
       FIG.  13    is a cross-sectional view taken along line IV-IV′ shown in  FIG.  12   . 
     For convenience of description, detailed elements of the thin film transistor layer  210  will be omitted in  FIG.  13   , and  FIG.  13    illustrates a TFT substrate  300  that the detailed elements of the thin film transistor layer  210 . 
     Referring to  FIG.  13   , an organic light emitting diode  380 , an encapsulation film  390  and a protective film  240  are formed on the TFT substrate  300 . Since the organic light emitting diode  380  and the encapsulation film  390 , which are shown in  FIG.  13   , are substantially the same as those shown in  FIGS.  5  to  8   , their detailed description will be omitted. 
     The protective film  240  covers the encapsulation film  390  to protect the organic light emitting diode  380  and the encapsulation film  390  formed on the first substrate  11  while the first substrate  111  is moving to the place where the later process is performed. The protective film  240  is formed even on the non-display area NDA as well as the display area DA to cover the encapsulation film  390 , and may not be formed on the pad area PA of the non-display area NDA. 
     The protective film  240  includes the substrate layer  242 , the first adhesive layer  244  and the second adhesive layer  246 , and the substrate layer  242  and the encapsulation film  390  are adhered to each other by the first adhesive layer  244  and the second adhesive layer  246 . 
     The first adhesive layer  244  is formed at the edge area of the substrate layer  242 , and is not formed at the center area of the substrate layer  242 . At this time, the edge area of the substrate layer  242  provided with the first adhesive layer  244  is overlapped with the non-display area NDA, and may partially be overlapped with the display area DA. However, even though the first adhesive layer  244  is partially overlapped with the display area DA, the first adhesive layer  244  is not formed to be overlapped with the second electrode  383  of the organic light emitting diode  380 . 
     The second adhesive layer  246  is formed at the center area of the substrate layer  242 . The second adhesive layer  246  is overlapped with the display area DA, and may be overlapped with the second electrode  383  formed on the display area DA. 
     The second adhesive layer  246  has adhesion smaller than that of the first adhesive layer  244 . Since the second adhesive layer  246  is overlapped with the second electrode  383 , if its adhesion is great, a problem occurs in that the second electrode  383  is separated from the organic light emitting layer  382  by adhesion of the second adhesive layer  246  when the protective film  240  is removed. On the other hand, since the first adhesive layer  244  is not overlapped with the second electrode  383 , the first adhesive layer  244  may have adhesion greater than that of the second adhesive layer  244 . Adhesion between the first adhesive layer  244  and the encapsulation film  390  may be greater than that between the second electrode  383  and the organic light emitting layer  382 . 
     Meanwhile, to solve the problem that the second electrode  383  is separated from the organic light emitting layer  382  when the protective film  240  is removed, adhesion between the second adhesive layer  246  and the encapsulation film  390  should be smaller than that between the second electrode  383  and the organic light emitting layer  382 . 
     Also, although  FIG.  12    shows that the second adhesive layer  246  is formed on the entire surface of the center area surrounded by the first adhesive layer  244 , the present invention is not limited to the example of  FIG.  12   . The second adhesive layer  246  may be formed of a plurality of patterns as shown in  FIG.  14   . In this case, the adhesion between the second adhesive layer  246  and the encapsulation film  390  is dispersed, a force for pulling the second electrode  383  per unit area when the protective film  240  is removed may be reduced. 
     In the second embodiment of the present invention, the adhesion between the second adhesive layer  246  and the encapsulation film  390  is smaller than that between the second electrode  383  and the organic light emitting layer  382 , whereby the second electrode  383  may be prevented from being separated from the organic light emitting layer  382  when the protective film  240  is removed. 
     Also, in the second embodiment of the present invention, the second adhesive layer  246  is formed of a plurality of patterns, whereby the adhesion of the second adhesive layer  246  may be dispersed. Therefore, since the force for pulling the second electrode  383  per unit area when the protective film  240  is removed may be reduced, the second electrode  383  may more effectively be prevented from being separated from the organic light emitting layer  382 . 
     Also, in the second embodiment of the present invention, since the adhesion of the first adhesive layer  244  is greater than that of the second adhesive layer  246 , the protective film  240  may be prevented from being separated from the first substrate  111  while the first substrate  111  is moving to the place where the later process is performed. 
     Although  FIG.  12    shows that the first adhesive layer  244  is overlapped with a part of the display area DA, the present invention is not limited to the example of  FIG.  12   . In another embodiment, the first adhesive layer  244  may not be overlapped with the display area DA. For example, if the second electrode  383  is formed to be extended to the non-display area NDA, the first adhesive layer  244  may not be overlapped with the display area DA. At this time, the first adhesive layer  244  may be formed to be overlapped with a part of the non-display area NDA and at the same time so as not to be overlapped with the second electrode  383 . 
     Although  FIG.  12    shows that the first adhesive layer  244  is not formed on the pad area PA, the present invention is not limited to the example of  FIG.  12   . In another embodiment, the first adhesive layer  244  may be formed on the non-display area NDA including the pad area. 
     Also, although  FIG.  12    shows that the first adhesive layer  244  is formed at four edge areas of the substrate layer  242 , the present invention is not limited to the example of  FIG.  12   . In another embodiment, the first adhesive layer  244  may be formed at only two edge areas of the substrate layer  242 , which face each other. 
     As shown in  FIG.  16 A , the pixels are formed on the display area DA of the TFT substrate  300  provided with the thin film transistor layer shown in  FIG.  6   . In more detail, referring to  FIG.  6   , a buffer film is formed on the first substrate  111 . The buffer film may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     First of all, pixels P are formed on a display area DA (S 1501  of  FIG.  15   ). 
     As shown in  FIG.  16 A , the pixels P are formed on the display area DA of the first substrate  111 . In more detail, a buffer film is formed on the first substrate  111 . The buffer film may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     Then, an active layer  311  is formed on the buffer film. The active layer  311  may be formed of a silicon based semiconductor material or an oxide based semiconductor material. 
     Then, a gate insulating film  330  is formed on the active layer  311 . The gate insulating film  330  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     A gate electrode  312  and a lower electrode  321  of a capacitor  320  are formed on the gate insulating film  330 . Each of the gate electrode  312  and the lower electrode  321  may be, but not limited to, a single layer or multi-layer comprised of any one of Mo, Al, Cr, Au, Ti, Ni, Nd and Cu or their alloy. 
     Then, an inter-layer dielectric layer  340  is formed on the gate electrode  312  and the lower electrode  321 . The inter-layer dielectric layer  340  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film, or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     Then, contact holes CH 1  and CH 2  for exposing the active layer  312  are formed to pass through the gate insulating film  330  and the inter-layer dielectric layer  340 . 
     Then, a source electrode  313 , a drain electrode  314 , and an upper electrode  322  of the capacitor  320  are formed on the inter-layer dielectric layer  340 . Each of the source electrode  313 , the drain electrode  314  and the upper electrode  322  may be, but not limited to, a single layer or multi-layer comprised of any one of Mo, Al, Cr, Au, Ti, Ni, Nd and Cu or their alloy. 
     Then, a passivation film  350  is formed on the thin film transistor  310  and the capacitor  320 . The passivation film  350  may serve as an insulating film. The passivation film  350  may be formed of an inorganic film, for example, a silicon oxide film, a silicon nitride film, or a multi-layered film of the silicon oxide film and the silicon nitride film. 
     Then, a planarization film  360  is formed on the passivation film  350 . The planarization film  360  may be formed of an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin. 
     Then, a contact hole CH 3  for exposing the source or drain electrode of the thin film transistor  310  is formed to pass through the passivation film  350  and the planarization film  360 , and a first electrode  381  is formed. The first electrode  381  may be formed of a metal material having high reflectivity such as a deposition structure (Ti/Al/Ti) of Al and Ti, a deposition structure (ITO/Al/ITO) of Al and ITO, an APC alloy, and a deposition structure (ITO/APC/ITO) of APC alloy and ITO. The APC alloy is an alloy of Ag, Pd and Cu. 
     Then, a bank  384  is formed on the planarization film  360  to cover an edge of the first electrode  381 , thereby partitioning emission areas EA. The bank  384  may be formed of an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin. 
     Then, an organic light emitting layer  382  is formed on the first electrode  381  and the bank  384 . A second electrode  383  is formed on the organic light emitting layer  382 . The second electrode  383  may be formed of a transparent conductive material (TCO) such as ITO and IZO, which may transmit light, or a semi-transmissive conductive material such as Mg, Ag, or alloy of Mg and Ag. A capping layer may be formed on the second electrode  383 . 
     Meanwhile, a dam  295  may further be formed on the non-display area NDA. The dam  295  may be formed simultaneously with the planarization film  360  or the bank  384 . The dam  295  may be formed of an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin. 
     Next, an encapsulation film  390  is formed to cover the display area DA (S 1502  of  FIG.  15   ). 
     As shown in  FIG.  16 B , the encapsulation film  390  is formed on the second electrode  390 . In more detail, a first inorganic film  391  is formed to cover the display area DA. At this time, the first inorganic film  391  is formed using a CVD method or an ALD method. The first inorganic film  391  may be formed of a silicon nitride, an aluminum nitride, a zirconium nitride, a titanium nitride, a hafnium nitride, a tantalum nitride, silicon oxide, an aluminum oxide, or a titanium oxide. 
     Then, an organic film  392  is formed to cover the first inorganic film  391 . The organic film  392  may be formed of an organic material, which may transmit light emitted from the organic light emitting layer  382  at 99% or more, for example, acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin. 
     Then, a second inorganic film  393  is formed to cover the organic film  392 . The second inorganic film  393  may be formed of a silicon nitride, an aluminum nitride, a zirconium nitride, a titanium nitride, a hafnium nitride, a tantalum nitride, silicon oxide, an aluminum oxide, or a titanium oxide. 
     Next, a protective film  240  is formed on the encapsulation film  390  (S 1503  of  FIG.  15   ). 
     As shown in  FIG.  16 C , the protective film  240  is attached onto the encapsulation film  390 . The protective film  240  includes a substrate layer  242  and a first adhesive layer  244 . The first adhesive layer  244  is formed at the edge area of the substrate layer  242  and then overlapped with the non-display area NDA of the first substrate  111 . Also, the first adhesive layer  244  may be overlapped with a part of the display area DA of the first substrate  111  but is not overlapped with the second electrode  383 . The first adhesive layer  244  may be an adhesive resin, and its adhesion may be greater than adhesion between the second electrode  383  and the organic light emitting layer  382 . 
     In addition, the protective film  240  may further include a second adhesive layer  246  (e.g., see  FIG.  11   ) formed on at the center area of the substrate layer  242 . The second adhesive layer  246  may be overlapped with the second electrode  383  unlike the first adhesive layer  244 , and its adhesion may be smaller than adhesion between the second electrode  383  and the organic light emitting layer  382 . Also, the second adhesive layer  246  may be formed on the entire center area of the substrate layer  242 , or may be formed of a plurality of patterns at the center area of the substrate layer  242 . 
     Next, the protective film  240  is removed (S 1504  of  FIG.  15   ). 
     As shown in  FIG.  16 D , the protective film  240  is removed. In more detail, the first substrate  111  provided with the organic light emitting diode  380  and the encapsulation film  390  moves to a place where a later process is performed in a state that the protective film  240  is attached thereonto. Then, the protective film  240  is removed from the first substrate  111  before the later process is performed. 
     Next, the first substrate  111  and the second substrate  112  are bonded to each other (S 1505  of  FIG.  15   ). 
     As shown in  FIG.  16 E , the second substrate  112  is bonded to the first substrate  111  from which the protective film  240  is removed. Although not shown in detail, first to third color filters and a black matrix may be formed on the second substrate  112 . A red color filter may be formed on a red emission portion, a blue color filter may be formed on a blue emission portion, and a green color filter may be formed on a green emission portion. In this case, the encapsulation film  390  of the first substrate  111  and is adhered to the color filters of the second substrate  112  by an adhesive layer  410 , whereby the first substrate  111  and the second substrate  112  may be bonded to each other. At this time, the adhesive layer  410  may be formed on all areas where the first substrate  111  and the second substrate  112  are overlapped with each other, and its adhesion may be greater than adhesion between the second electrode  383  and the organic light emitting layer  382 . 
     Otherwise, the first to third color filters and the black matrix may directly be formed on the encapsulation film  390  of the first substrate  111  from which the protective film  240  is removed, through the later process. In this case, the color filters of the first substrate  111  may be adhered to the second substrate  112  by the adhesive layer  410 . 
     Otherwise, a touch panel may be formed on the second substrate  112 . At this time, the touch panel may be provided with a first touch electrode and a second touch electrode. In this case, the encapsulation film  390  of the first substrate  111  may be adhered to the touch panel of the second substrate  112  by the adhesive layer  410 . 
     Otherwise, the second touch electrode may only be formed on the second substrate  112 . The first touch electrode may directly be formed on the encapsulation film  390  of the first substrate  111  from which the protective film  240  is removed, through the later process. In this case, the first substrate  111  provided with the first touch electrode may be adhered to the second substrate  112  provided with the second touch electrode by the adhesive layer  410 . 
     Otherwise, a polarizer may be formed on the second substrate  112 . In this case, the encapsulation film  390  of the first substrate  111  may be adhered to the polarizer of the second substrate  112  by the adhesive layer  410 . 
     Meanwhile, although the protective film  240  is attached onto the encapsulation film  390  and then removed in  FIGS.  15  and  16   , the present invention is not limited to the examples of  FIGS.  15  and  16   . In another embodiment, electrode patterns, for example, the first touch electrode and the second touch electrode may further be formed on the encapsulation film  390 . In this case, the protective film  240  may be attached onto the electrode patterns and then removed therefrom after the first substrate moves to the place where the later process is performed. 
     As described above, according to one or more embodiments of the present invention, the following advantages can be obtained. 
     The first substrate provided with the organic light emitting diode and the encapsulation film moves to the place where the later process is performed in a state that the protective film is attached onto the encapsulation film, whereby particles may be prevented from being permeated into the organic light emitting diode and the encapsulation film or the organic light emitting diode and the encapsulation film may be prevented from being damaged while the first substrate is moving to the place where the later process is performed. 
     Also, the first adhesive layer for adhering the protective film to the encapsulation film is formed at only the edge area and formed so as not to be overlapped with the second electrode, whereby the second electrode may be prevented from being separated from the organic light emitting layer when the protective film is removed from the place where the later process is performed. Therefore, yield and reliability of the display device may be improved. 
     Also, the second adhesive layer for adhering the protective film to the encapsulation film is formed to be overlapped with the second electrode and its adhesion is smaller than the adhesion between the second electrode and the organic light emitting layer, whereby the second electrode may be prevented from being separated from the organic light emitting layer when the protective film is removed from the place where the later process is performed. 
     Also, the second adhesive layer is formed of a plurality of patterns, whereby the adhesion of the second adhesive layer may be dispersed. Therefore, since the force for pulling the second electrode per unit area when the protective film is removed may be reduced, the second electrode may more effectively be prevented from being separated from the organic light emitting layer. 
     Also, since the adhesion of the first adhesive layer is greater than the adhesion between the second electrode and the organic light emitting layer, the protective film may be prevented from being separated from the first substrate while the first substrate is moving to the place where the later process is performed. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Thus, the above embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention should be determined by reasonable interpretation of the appended claims and all change which comes within the equivalent scope of the invention are included in the scope of the invention.