Patent Publication Number: US-2016239143-A1

Title: Display device and method of manufacturing the display device

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 10-2015-0024021, filed on Feb. 17, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     The described technology generally relates to a display device and a method of manufacturing the display device. 
     2. Description of the Related Technology 
     Recently, various types of display devices that have thin profiles and are lightweight are being used. Legacy display devices are being replaced with portable thin flat panel display devices. Also, a panel having touch functionality can be included in display devices. 
     SUMMARY OF CERTAIN INVENTIVE ASPECTS 
     One inventive aspect relates to a display device having a panel with touch functionality and a method of manufacturing the display device. 
     Another aspect is a display device that includes a substrate; a display unit formed on a surface of the substrate and including a display device configured to realize an image; and a touch pattern formed on other surface of the substrate opposite the surface of the substrate on which the display unit is formed, wherein the touch pattern has conductivity and is configured to recognize a user&#39;s touch. 
     The display device can further include a touch mutual electrode formed on a surface of the display unit or in the display unit so as to face the touch pattern. 
     The touch pattern can include a plurality of conductive patterns that extend in a first direction, and the touch mutual electrode can include a plurality of conductive patterns that extend in a second direction crossing the first direction. 
     The touch pattern can include a transmissive conductive material. 
     The display unit can include at least one thin-film transistor (TFT) electrically connected to the display device, and the TFT can include an active layer, a gate electrode, a source electrode, and a drain electrode. 
     The display device can further include a touch mutual electrode formed of same material as the gate electrode and formed to face the touch pattern. 
     The display device can further include a scan line configured to apply a scan signal to the display device of the display unit and electrically connected to the gate electrode, and the scan line can be formed to face the touch pattern so that the display device can detect a change in a capacitance between the scan line and the touch pattern to recognize the user&#39;s touch. 
     The scan line can include one or more conductive lines that extend in a first direction, and the touch pattern can include a plurality of conductive patterns that extend in a second direction crossing the first direction. 
     The display device can further include a touch mutual electrode that is formed of a same material as the source electrode or the drain electrode and is formed to face the touch pattern. 
     The display device can further include a touch mutual electrode formed between the active layer and the gate electrode and facing the touch pattern. 
     The touch pattern can include a light-shielding material. 
     The touch pattern can have a plurality of openings. 
     The display device can further include a protective layer that covers the touch pattern. 
     The substrate can include a light-transmitting material. 
     The display device can further include an encapsulating unit that covers the display unit. 
     The display device can include an organic light-emitting device that includes a first electrode, a second electrode, and an intermediate layer, and the intermediate layer can be formed between the first electrode and the second electrode and at least can include an organic emission layer. 
     Another aspect is a method of manufacturing a display device that includes forming, on a surface of a substrate, a display unit that includes a display device configured to realize an image; and forming a touch pattern on other surface of the substrate opposite the surface of the substrate on which the display unit is formed, wherein the touch pattern has conductivity and is configured to recognizes a user&#39;s touch. 
     After the operation of forming the display unit, the method can further include an operation of forming an encapsulating unit that covers the display unit, and the operation of forming the touch pattern can be performed after the operation of forming the encapsulating unit. 
     The method can further include an operation of flipping over the substrate, and the operation of forming the touch pattern can be performed after the operation of forming the encapsulating unit and the operation of flipping over the substrate are performed after the forming of the encapsulating unit. 
     Another aspect is a display device comprising: a substrate having first and second surfaces opposing each other; a display layer formed over the first surface of the substrate and comprising a display element configured to generate an image; and a touch pattern formed over the second surface of the substrate, wherein the touch pattern is conductive and configured to recognize a touch thereon. 
     The above display device further comprises a touch mutual electrode formed over the display layer or in the display layer so as to face the touch pattern. 
     In the above display device, the touch pattern comprises a plurality of first conductive patterns extending in a first direction, wherein the touch mutual electrode comprises a plurality of second conductive patterns extending in a second direction crossing the first direction. 
     In the above display device, the touch pattern is formed of a transmissive conductive material. 
     In the above display device, the display layer comprises at least one thin-film transistor (TFT) electrically connected to the display element, wherein the at least one TFT comprises an active layer, a gate electrode, a source electrode, and a drain electrode. 
     The above display device further comprises a touch mutual electrode formed of the same material as the gate electrode and facing the touch pattern. 
     The above display device further comprises a scan line configured to apply a scan signal to the display element and electrically connected to the gate electrode, wherein the scan line faces the touch pattern, and wherein the touch pattern is further configured to detect a change in a capacitance between the scan line and the touch pattern so as to recognize the touch. 
     In the above display device, the scan line comprises one or more conductive lines extending in a first direction, wherein the touch pattern comprises a plurality of conductive patterns extending in a second direction crossing the first direction. 
     The above display device further comprises a touch mutual electrode formed of the same material as the source electrode or the drain electrode, wherein the touch mutual electrode faces the touch pattern. 
     The above display device further comprises a touch mutual electrode formed between the active layer and the gate electrode and facing the touch pattern. 
     In the above display device, the touch pattern is formed of a light-shielding material. 
     In the above display device, the touch pattern has a plurality of openings. 
     In the above display device, the openings are configured to decrease light-shielding in the touch pattern. 
     The above display device further comprises a protective layer at least partially covering the touch pattern. 
     In the above display device, the substrate is formed of a light-transmitting material. 
     The above display device further comprises an encapsulating layer covering the display layer. 
     In the above display device, the display element comprises an organic light-emitting diode (OLED) including a first electrode, a second electrode, and an intermediate layer, wherein the intermediate layer is formed between the first and second electrodes and comprises an organic emission layer. 
     Another aspect is a method of manufacturing a display device, the method comprising: forming a display layer over a first surface of a substrate, wherein the display layer comprises a display element configured to generate an image; and forming a touch pattern over a second surface of the substrate opposing the first surface, wherein the touch pattern is conductive and configured to recognize a touch thereon. 
     The above method further comprises forming an encapsulating layer covering the display layer, wherein the touch pattern formed after the encapsulating layer. 
     The above method further comprises flipping over the substrate, wherein the touch pattern is formed after the encapsulating layer, and wherein the substrate is flipped over after the encapsulating layer is formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view that illustrates a display device according to an exemplary embodiment. 
         FIG. 2  illustrates an enlarged view of a portion K of the display device shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view that illustrates a modified embodiment of the display device shown in  FIG. 1 . 
         FIG. 4  is a cross-sectional view that illustrates a display device according to another exemplary embodiment. 
         FIG. 5  illustrates an enlarged view of a portion K of the display device shown in  FIG. 4 . 
         FIG. 6  show a circuit diagram that illustrates a touch pattern of the display device shown in  FIG. 4 . 
         FIG. 7  is a cross-sectional view that illustrates a display device according to another exemplary embodiment. 
         FIG. 8  is a magnified view that illustrates a portion K of the display device shown in  FIG. 7 . 
         FIG. 9  shows a circuit diagram that illustrates a touch pattern of the display device shown in  FIG. 7 . 
         FIG. 10  is a cross-sectional view that illustrates a display device according to another exemplary embodiment. 
         FIG. 11  illustrates an enlarged view of a portion K of the display device shown in  FIG. 10 . 
         FIG. 12  is a plan view of the portion K of  FIG. 10  seen in direction A of  FIG. 11 . 
         FIGS. 13 and 14  are diagrams illustrating a method of manufacturing a display device, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS 
     A display device that has the touch functionality includes a plurality of conductive patterns. In order to improve the accuracy of this functionality, it is important to improve manufacturing characteristics of the conductive patterns. 
     As the described technology allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. Effects and features of the described technology and methods of accomplishing the same can be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. The described technology can, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. 
     Hereinafter, one or more exemplary embodiments will be described below in more detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and redundant explanations are omitted. 
     Hereinafter, in one or more exemplary embodiments, while such terms as “first,” “second,” etc., can be used, but such components must not be limited to the above terms, and the above terms are used only to distinguish one component from another. 
     Hereinafter, in one or more exemplary embodiments, a singular form can include plural forms, unless there is a particular description contrary thereto. 
     Hereinafter, in one or more exemplary embodiments, terms such as “comprise” or “comprising” are used to specify existence of a recited feature or component, not excluding the existence of one or more other recited features or one or more other components. 
     Hereinafter, in one or more exemplary embodiments, it will also be understood that when an element such as layer, region, area, or component is referred to as being “on” another element, it can be directly on the other element, or intervening elements such as layer, region, area, or component can also be interposed therebetween. 
     In the drawings, for convenience of description, the sizes of layers and regions are exaggerated for clarity. For example, a size and thickness of each element can be random for convenience of description, thus, one or more exemplary embodiments are not limited thereto. 
     Hereinafter, in one or more exemplary embodiments, X-axis, Y-axis, and Z-axis are not be limited to three axes on a rectangular coordinate system but can be interpreted as a broad meaning including the three axes. For example, the X-axis, Y-axis, and Z-axis can be perpendicular to each other or can indicate different directions that are not perpendicular to each other. 
     In one or more exemplary embodiments, an order of processes can be different from that is described. For example, two processes that are sequentially described can be substantially simultaneously or concurrently performed, or can be performed in an opposite order to the described order. 
     Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. In this disclosure, the term “substantially” includes the meanings of completely, almost completely or to any significant degree under some applications and in accordance with those skilled in the art. The term “connected” can include an electrical connection. 
       FIG. 1  illustrates a cross-sectional view of a display device  100  according to an exemplary embodiment.  FIG. 2  illustrates an enlarged view of a portion K of the display device  100  shown in  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , the display device  100  includes a substrate  101 , a display unit (or display layer) DU, a touch pattern TP, and an encapsulating unit (or encapsulating layer) EU. 
     Elements of the display device  100  are described below in detail. 
     The substrate  101  can be formed of various materials. For example, the substrate  101  is formed of a glass material. 
     In some embodiments, the substrate  101  is formed of material having excellent light transmittance. Thus, a visible ray generated in the display unit DU to be described later can pass through the substrate  101  and reach a user. That is, the display device  100  can be of a bottom emission type and the user can recognize an image realized in the display device  100  below the substrate  101  shown in  FIG. 1 . 
     In the present embodiment, the substrate  101  is formed of a flexible material, and in some embodiments, the substrate  101  is formed of an organic material. For example, the substrate  101  is formed of an organic material such as polyimide, polyethylene napthalate, polyethyleneterephthalate (PET), polyarylate, polycarbonate, polyether imide (PEI), or polyethersulfone that has excellent heat-resistance and durability. 
     Although not illustrated, at least one barrier layer (not shown) and at least one buffer layer (not shown) can be selectively formed between the substrate  101  and the display unit DU, and by doing so, it is possible to decrease or to prevent foreign substances, moisture, or outside air from penetrating into the display device  100  via the substrate  101 . 
     The display unit DU is formed on the substrate  101 . The display unit DU includes a display device that generates a visible ray for realizing an image that is recognizable to the user. 
     The display device can be variously formed to generate the visible ray, and for example, is a liquid crystal display device, an organic light-emitting diode (OLED), or the like. 
     In this disclosure, for convenience of description, it is assumed that the display device includes an OLED  130  as shown in  FIG. 2 . 
     In some embodiments, the display device  100  further includes a touch mutual electrode TE. 
     The display device  100  can sense a user&#39;s touch via the touch mutual electrode TE and the touch pattern TP, e.g., when the user touches the touch pattern TP, the display device  100  senses the touch via the touch mutual electrode TE and the touch pattern TP. For example, the display device  100  recognizes the user&#39;s touch by detecting a change in capacitance between the touch mutual electrode TE and the touch pattern TP. 
     In some embodiments, a position of the touch mutual electrode TE is changed, and for example, the touch mutual electrode TE is formed on the OLED  130 . 
     In some embodiments, only the touch pattern TP is formed, and the touch mutual electrode TE is not formed. That is, the display device  100  can recognize a user&#39;s touch via only the touch pattern TP. For example, the touch pattern TP has a touch pattern in a first direction and another touch pattern that is electrically insulated from the touch pattern and is arranged in a second direction that crosses the first direction, and the display device  100  can recognize the user&#39;s touch by detecting a change in capacitance between the touch pattern in the first direction and the other touch pattern in the second direction. 
     The OLED  130  can include a first electrode  131 , a second electrode  132 , and an intermediate layer  133 . 
     The first electrode  131  can be formed on the touch mutual electrode TE by using various conductive materials. In some embodiments, the first electrode  131  is formed of ITO, IZO, ZnO, or In 2 O 3 . In some embodiments, the first electrode  131  includes a reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Yb, or Ca. 
     The intermediate layer  133  is formed on the first electrode  131 . The intermediate layer  133  includes an organic emission layer so as to generate a visible ray. The intermediate layer  133  can be a small-molecule organic layer or a polymer organic layer. Also, the intermediate layer  133  can include the organic emission layer, and can further include at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL). 
     The second electrode  132  can be formed on the intermediate layer  133  by using various conductive materials. In some embodiments, the second electrode  132  is formed of a metal including Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, or Ca. 
     The touch pattern TP can be formed on a surface of the substrate  101  opposite the other surface of the substrate  101  that faces the display unit DU. By doing so, the touch pattern TP can affect forming of the display unit DU in a very small degree. The touch pattern TP can have various shapes. For example, the touch pattern TP has a plurality of conductive patterns that extend in one direction, and in this case, the touch mutual electrode TE has a plurality of conductive patterns that extend in one direction that crosses the direction in which the touch pattern TP extends. 
     Also, as described above, if the touch mutual electrode TE is not used, the display device  100  can recognize a user&#39;s touch via only the touch pattern TP, and in this case, the touch pattern TP can include conductive patterns that are insulated from each other and are formed in a first direction and a second direction that crosses the first direction. 
     The touch pattern TP can be formed of various materials. In some embodiments, the touch pattern TP is formed of a transmissive conductive material, e.g., ITO, IZO, ZnO, AZO, or In 2 O 3 . 
     By doing so, when a visible ray that is generated in the display unit DU passes through the substrate  101  and reaches the user, light-shielding due to the touch pattern TP can be sharply decreased. Therefore, the bottom emission type display device  100  can be easily embodied. 
     The encapsulating unit EU can be formed on the display unit DU and can cover the display unit DU. The encapsulating unit EU can have various shapes, be formed of various materials, and decrease or prevent foreign substances, moisture, or outside air from penetrating into the display unit DU. The encapsulating unit EU can include an organic layer or an inorganic layer. Alternatively, the encapsulating unit EU can be a stack layer of at least one organic layer and at least one inorganic layer. 
     The encapsulating unit EU can have a layer shape as shown in  FIG. 1  or can have a cover shape as shown in  FIG. 3 , where a display device  100 ′ is illustrated as a modified embodiment of the display device  100 . 
     Although not illustrated, in some embodiments, the encapsulating unit EU is an encapsulation substrate (not shown) that faces the substrate  101 , and the encapsulation substrate and the substrate  101  can be bonded to each other by using a sealing member (not shown). 
     Although not illustrated, a protective layer (not shown) can be further formed on the touch pattern TP by using an insulating material. 
     In the display device  100  according to the present embodiment, the encapsulating unit EU is formed on one surface of the substrate  101 , and the touch pattern TP is formed on the other surface of the substrate  101 . By doing so, the touch pattern TP can be easily formed without affecting a characteristic of the display unit DU during forming thereof. 
     For example, the touch pattern TP is formed on a bottom surface of the substrate  101 , i.e., the touch pattern TP is formed on the other surface of the substrate  101  where the display unit DU is not formed, thus, when the touch pattern TP is formed, a degree of freedom with respect to a touch pattern forming process is increased. 
     Also, since the touch pattern TP is formed on the bottom surface of the substrate  101  and formed of the transmissive conductive material, the bottom emission type display device  100  where an image is realized toward the substrate  101  can be easily embodied. 
     Also, since the display device  100  does not require a separate panel or a substrate so as to realize a touch recognition function, the thickness of the display device  100  having the touch recognition function can be decreased, and a characteristic of a manufacturing procedure with respect to the display device  100  can be improved. 
       FIG. 4  is a cross-sectional view that illustrates a display device  200  according to another exemplary embodiment.  FIG. 5  is a magnified view that illustrates a portion K of the display device  200  shown in  FIG. 4 .  FIG. 6  shows a circuit diagram that illustrates a touch pattern TP of the display device  200  shown in  FIG. 4 . 
     Referring to  FIGS. 4 through 6 , the display device  200  includes a substrate  201 , a display unit DU, the touch pattern TP, and an encapsulating unit EU. For convenience of description, the present embodiment will now be described with reference to its characteristics that are different from the previous embodiment. 
     The display unit DU is formed on the substrate  201 , and a display device and a thin film transistor (TFT) are formed in the display unit DU. The display device includes an OLED  230 , and the TFT includes an active layer  203 , a gate electrode  205 , a source electrode  207 , and a drain electrode  209 . 
     A material of the substrate  201  is the same as a material of the substrate  101 , and thus, detailed descriptions thereof are omitted here. 
     A buffer layer  202  is formed on the substrate  201 . The buffer layer  202  can provide a planar surface on a top surface of the substrate  201 , and can decrease or prevent foreign substances, moisture, or outside air from penetrating into the display device  200  via the substrate  201 . 
     The active layer  203  having a predetermined pattern is formed on a top surface of the buffer layer  202 . The active layer  203  can be formed of inorganic semiconductor material such as silicon, an organic semiconductor material, or an oxide semiconductor material, and can be formed by selectively injecting a p-type dopant or an n-type dopant. 
     A gate insulating layer  204  is formed on the active layer  203 . The gate electrode  205  is formed on the gate insulating layer  204  so as to have an area that overlaps with the active layer  203 . 
     The display device  200  can include scan lines SL that apply scan signals to the display unit DU. The scan lines SL can be formed of the same material as the gate electrode  205  and can be connected to the gate electrode  205 . In some embodiments, the display device  200  includes TFTs that are not shown in  FIGS. 4 and 5 , and the scan lines SL are formed of the same material as that of the gate electrodes of the TFTs and are connected to the gate electrodes of the TFTs. 
     An interlayer insulating layer  206  is formed to cover the gate electrode  205 , and the source electrode  207  and the drain electrode  209  are formed on the interlayer insulating layer  206 . 
     The source electrode  207  and the drain electrode  209  contact predetermined areas of the active layer  203 . 
     A passivation layer  208  can be formed to cover the source electrode  207  and the drain electrode  209 , and a separate planarization layer (not shown) can be further formed on the passivation layer  208 . 
     The OLED  230  is formed on the passivation layer  208 . The OLED  230  includes a first electrode  231 , an intermediate layer  233 , and a second electrode  232 . 
     The first electrode  231  is formed to be electrically connected to one of the source electrode  207  and the drain electrode  209 . 
     A pixel defining layer  215  is formed on the first electrode  231 . The pixel defining layer  215  does not cover a predetermined area of a top surface of the first electrode  231 . The intermediate layer  233  including an organic emission layer is formed on the top surface of the first electrode  231 . The second electrode  232  is formed on the intermediate layer  233 . 
     The touch pattern TP is formed on a bottom surface of the substrate  201 , e.g., the touch pattern TP is formed on a surface of the substrate  201  opposite the other surface of the substrate  201  that faces the display unit DU. By doing so, the touch pattern TP can affect forming of the display unit DU in a very small degree. The touch pattern TP can have various shapes. For example, the touch pattern TP includes a plurality of conductive patterns that extend in one direction. 
     As illustrated in  FIG. 6 , the touch pattern TP includes a plurality of conductive patterns that extend in one direction that crosses a direction in which the scan lines SL extend. That is, when a user touches the display device  200 , the display device  200  can realize a touch recognition function by detecting a change in capacitance between the touch pattern TP and the scan lines SL. 
     In some embodiments, the display device  200  recognizes a user&#39;s touch via only the touch pattern TP, and in this case, the touch pattern TP has conductive patterns that are insulated from each other and are arrayed in a first direction and a second direction that crosses the first direction. 
     The touch pattern TP can be formed of various materials. In some embodiments, the touch pattern TP is formed of a transmissive conductive material, e.g., ITO, IZO, ZnO, AZO, or In 2 O 3 . 
     By doing so, when a visible ray that is generated in the display unit DU passes through the substrate  201  and reaches the user, light-shielding due to the touch pattern TP can be sharply decreased. Therefore, the bottom emission type display device  200  can be easily embodied. 
     The encapsulating unit EU can be formed on the display unit DU and can cover the display unit DU. The encapsulating unit EU can have various shapes, can be formed of various materials, and can decrease or prevent foreign substances, moisture, or outside air from penetrating into the display unit DU. The encapsulating unit EU can include an organic layer or an inorganic layer. Alternatively, the encapsulating unit EU can be a stack layer of at least one organic layer and at least one inorganic layer. 
     The encapsulating unit EU can have a cover shape as shown in  FIG. 3 . 
     Although not illustrated, in some embodiments, the encapsulating unit EU is an encapsulation substrate (not shown) that faces the substrate  201 , and the encapsulation substrate and the substrate  201  are bonded to each other by using a sealing member (not shown). 
     Although not illustrated, a protective layer (not shown) can be further formed on the touch pattern TP by using an insulating material. 
     In the display device  200  according to the present embodiment, the encapsulating unit EU is formed on one surface of the substrate  201 , and the touch pattern TP is formed on the other surface of the substrate  201 . By doing so, the touch pattern TP can be easily formed without affecting a characteristic of the display unit DU during forming thereof. 
     For example, the touch pattern TP is formed on a bottom surface of the substrate  201 , i.e., the touch pattern TP is formed on the other surface of the substrate  201  where the display unit DU is not formed. Thus, when the touch pattern TP is formed, a degree of freedom of a process of forming a touch pattern is increased. 
     Also, since the touch pattern TP is formed on the bottom surface of the substrate  201  and includes the transmissive conductive material, the bottom emission type display device  200  where an image is realized toward the substrate  201  can be easily embodied. 
     Also, the touch pattern TP can be formed to cross the scan lines SL that are connected to the gate electrode  205  of the TFT in the display unit DU, so that a touch function can be easily implemented by using the scan lines SL as a touch mutual electrode, without separately forming the touch mutual electrode. 
     Also, since the display device  200  does not require a separate panel or a substrate so as to realize a touch recognition function, the thickness of the display device  200  having the touch recognition function can be decreased, and a characteristic of a manufacturing procedure with respect to the display device  200  can be improved. 
       FIG. 7  is a cross-sectional view that illustrates a display device  300  according to another exemplary embodiment.  FIG. 8  is a magnified view that illustrates a portion K of the display device  300  shown in  FIG. 7 .  FIG. 9  is a circuit diagram that illustrates a touch pattern TP of the display device  300  shown in  FIG. 7 . 
     Referring to  FIGS. 7 through 9 , the display device  300  includes a substrate  301 , a display unit DU, the touch pattern TP, and an encapsulating unit EU. For convenience of description, the present embodiment will now be described with reference to its characteristics that are different from the previous embodiment. 
     The display unit DU is formed on the substrate  301 , and a display device and a thin film transistor (TFT) are formed in the display unit DU. The display device includes an OLED  330 , and the TFT includes an active layer  303 , a gate electrode  305 , a source electrode  307 , and a drain electrode  309 . 
     A material of the substrate  301  is the same as a material of the substrate  101 , and thus, detailed descriptions thereof are omitted here. 
     A buffer layer  302  is formed on the substrate  301 . The buffer layer  302  can provide a planar surface on a top surface of the substrate  301 , and can decrease or prevent foreign substances, moisture, or outside air from penetrating into the display device  300  via the substrate  301 . 
     The active layer  303  having a predetermined pattern is formed on a top surface of the buffer layer  302 . The active layer  303  can be formed of an inorganic semiconductor material such as silicon, an organic semiconductor material, or an oxide semiconductor material, and can be formed by selectively injecting a p-type dopant or an n-type dopant. 
     A gate insulating layer  304  is formed on the active layer  303 . The gate electrode  305  is formed on the gate insulating layer  304  so as to have an area that overlaps with the active layer  303 . 
     The display device  300  can include scan lines SL that apply scan signals to the display unit DU. The scan lines SL can be formed of the same material as the gate electrode  305  and can be connected to the gate electrode  305 . In some embodiments, the display device  300  includes TFTs that are not shown in  FIGS. 7 and 8 , and the scan lines SL can be formed of the same material as gate electrodes of the TFTs and can be connected to the gate electrodes of the TFTs. 
     A touch mutual electrode TE is formed on the gate insulating layer  304 . 
     The display device  300  can sense a user&#39;s touch via the touch mutual electrode TE and the touch pattern TP, e.g., when the user touches the touch pattern TP, the display device  300  can sense the touch via the touch mutual electrode TE and the touch pattern TP. For example, the display device  300  recognizes the user&#39;s touch by detecting a change in capacitance between the touch mutual electrode TE and the touch pattern TP. The touch mutual electrode TE can be formed of the same material as the gate electrode  305 . 
     In some embodiments, a position of the touch mutual electrode TE is changed. For example, the touch mutual electrode TE is formed on the buffer layer  302 . As another example, another insulating layer (not shown) can be further formed between the gate insulating layer  304  and the gate electrode  305 , and the touch mutual electrode TE can be formed between the other insulating layer and the gate insulating layer  304 . 
     In some embodiments, the touch mutual electrode TE is formed on an interlayer insulating layer  306  by using a same material as the source electrode  307  or the drain electrode  309 . 
     Referring to  FIG. 8 , the interlayer insulating layer  306  is formed to cover the gate electrode  305  and the touch mutual electrode TE, and the source electrode  307  and the drain electrode  309  are formed on the interlayer insulating layer  306 . 
     The source electrode  307  and the drain electrode  309  contact predetermined areas of the active layer  303 . 
     A passivation layer  308  can be formed to cover the source electrode  307  and the drain electrode  309 , and a separate planarization layer (not shown) can be further formed on the passivation layer  308 . 
     The OLED  330  is formed on the passivation layer  308 . The OLED  330  includes a first electrode  331 , an intermediate layer  333 , and a second electrode  332 . 
     The first electrode  331  is formed to be electrically connected to one of the source electrode  307  and the drain electrode  309 . 
     A pixel defining layer  315  is formed on the first electrode  331 . The pixel defining layer  315  does not cover a predetermined area of a top surface of the first electrode  331 . The intermediate layer  333  including an organic emission layer is formed on the top surface of the first electrode  331 . The second electrode  332  is formed on the intermediate layer  333 . 
     The touch pattern TP is formed on a bottom surface of the substrate  301 , e.g., the touch pattern TP is formed on a surface of the substrate  301  opposite the other surface of the substrate  301  that faces the display unit DU. By doing so, the touch pattern TP can affect forming of the display unit DU in a very small degree. The touch pattern TP can have various shapes. For example, the touch pattern TP can include a plurality of conductive patterns that extend in one direction. 
     As illustrated in  FIG. 9 , the touch pattern TP includes a plurality of conductive patterns that extend in one direction that crosses a direction in which the touch mutual electrode TE extends. That is, when a user touches the display device  300 , the display device  300  can realize a touch recognition function by detecting a change in capacitance between the touch pattern TP and the touch mutual electrode TE. 
     The touch pattern TP can be formed of various materials. In some embodiments, the touch pattern TP is formed of a transmissive conductive material, e.g., ITO, IZO, ZnO, AZO, or In 2 O 3 . 
     By doing so, when a visible ray that is generated in the display unit DU passes through the substrate  301  and reaches the user, light-shielding due to the touch pattern TP can be sharply decreased. Therefore, the bottom emission type display device  300  can be easily embodied. 
     The encapsulating unit EU can be formed on the display unit DU and can cover the display unit DU. The encapsulating unit EU can have various shapes, can be formed of various materials, and can decrease or prevent foreign substances, moisture, or outside air from penetrating into the display unit DU. The encapsulating unit EU can include an organic layer or an inorganic layer. Alternatively, the encapsulating unit EU can be a stack layer of at least one organic layer and at least one inorganic layer. 
     The encapsulating unit EU can have a cover shape as shown in  FIG. 3 . 
     Although not illustrated, in some embodiments, the encapsulating unit EU is an encapsulation substrate (not shown) that faces the substrate  301 , and the encapsulation substrate and the substrate  301  can be bonded to each other by using a sealing member (not shown). 
     Although not illustrated, a protective layer (not shown) can be further formed on the touch pattern TP by using an insulating material. 
     In the display device  300  according to the present embodiment, the encapsulating unit EU is formed on one surface of the substrate  301 , and the touch pattern TP is formed on the other surface of the substrate  301 . Thus, the touch pattern TP can be easily formed without affecting a characteristic of the display unit DU during forming thereof. 
     For example, the touch pattern TP is formed on a bottom surface of the substrate  301 , i.e., the touch pattern TP is formed on the other surface of the substrate  301  where the display unit DU is not formed, thus, when the touch pattern TP is formed, a degree of freedom with respect to a touch pattern forming process is increased. 
     Also, since the touch pattern TP is formed on the bottom surface of the substrate  301  and is formed of the transmissive conductive material, the bottom emission type display device  300  where an image is realized toward the substrate  301  can be easily embodied. 
     When the touch mutual electrode TE is formed of the same material as the gate electrode  305  arranged in the display unit DU, production efficiency can be improved. Also, since the touch mutual electrode TE is formed on one of the layers included in the TFT of the display unit DU, the production efficiency can be further improved. 
     Also, since the display device  300  does not require a separate panel or a substrate so as to realize a touch recognition function, the thickness of the display device  300  having the touch recognition function can be decreased, and a characteristic of a manufacturing procedure with respect to the display device  200  can be improved. 
       FIG. 10  illustrates a cross-sectional view of a display device  400  according to another exemplary embodiment.  FIG. 11  is an enlarged view of a portion K of the display device  400  shown in  FIG. 10 .  FIG. 12  is a plan view of the portion K of  FIG. 10  seen in direction A of  FIG. 11 . For convenience of description, the present embodiment will now be described with reference to characteristics different from the previous embodiment. 
     Referring to  FIGS. 10 through 12 , the display device  400  includes a substrate  401 , a display unit DU, the touch pattern TP, and an encapsulating unit EU. 
     The display unit DU is formed on the substrate  401 , and the touch pattern TP is formed on a bottom surface of the substrate  401 , i.e., a surface of the substrate  401  opposite the other surface of the substrate  401  whereon the display unit DU is formed. 
     A material of the substrate  401  is the same as the material of the substrate  101 , and thus, detailed descriptions thereof are omitted here. 
     Although not illustrated, at least one barrier layer (not shown) and at least one buffer layer (not shown) can be formed between the substrate  401  and the display unit DU, and by doing so, it is possible to decrease or to prevent foreign substances, moisture, or outside air from penetrating into the display device  400  via the substrate  401 . 
     The display unit DU is formed on the substrate  401 . The display unit DU includes an OLED  430  that is a display device. 
     In some embodiments, the display device  400  further includes a touch mutual electrode TE. 
     The display device  400  can sense a user&#39;s touch via the touch mutual electrode TE and the touch pattern TP, e.g., when the user touches the touch pattern TP, the display device  400  can sense the touch via the touch mutual electrode TE and the touch pattern TP. For example, the display device  400  recognizes the user&#39;s touch by detecting a change in capacitance between the touch mutual electrode TE and the touch pattern TP. 
     In some embodiments, a position of the touch mutual electrode TE changes. For example, the touch mutual electrode TE is formed on the OLED  430 . 
     In some embodiments, only the touch pattern TP is arranged, and the touch mutual electrode TE can be omitted. That is, the display device  400  can recognize the user&#39;s touch via only the touch pattern TP. For example, the touch pattern TP includes a touch pattern in a first direction and another touch pattern that is electrically insulated from the touch pattern and is arranged in a second direction that crosses the first direction, and the display device  400  can recognize the user&#39;s touch by detecting a change in capacitance between the touch pattern in the first direction and the other touch pattern in the second direction. 
     The OLED  430  includes a first electrode  431 , a second electrode  432 , and an intermediate layer  433 . 
     The first electrode  431  can be formed on the touch mutual electrode TE. 
     The intermediate layer  433  is formed on the first electrode  431 . The intermediate layer  433  includes an organic emission layer so as to generate a visible ray. 
     The second electrode  432  is formed on the intermediate layer  433 . The second electrode  432  can be formed of various conductive materials. 
     The touch pattern TP can be formed on a surface of the substrate  401  opposite the other surface of the substrate  401  that faces the display unit DU. By doing so, the touch pattern TP can affect forming of the display unit DU in a very small degree. The touch pattern TP can have various shapes. For example, the touch pattern TP has a plurality of conductive patterns that extend in one direction, and in this case, the touch mutual electrode TE has a plurality of conductive patterns that extend in one direction that crosses the direction in which the touch pattern TP extends. 
     Also, as described above, if the touch mutual electrode TE is not arranged, the display device  100  can recognize a user&#39;s touch via only the touch pattern TP, and in this case, the touch pattern TP can include conductive patterns that are insulated from each other and are arrayed in a first direction and a second direction that crosses the first direction. 
     The touch pattern TP can be formed of various materials. In some embodiments, the touch pattern TP is formed of a conductive material and a light-shielding material. For example, the touch pattern TP is formed of chromium (Cr), nickel (Ni), molybdenum (Mo), or iron (Fe). 
     By doing so, when a visible ray generated in the display unit DU passes through the substrate  401  and reaches a user, reflection of external light can be decreased due to the touch pattern TP, so that a contrast can be improved. 
     In order to significantly decrease shielding of a visible ray generated in the OLED  430  by the touch pattern TP, the touch pattern TP can have a plurality of openings TPW as illustrated in  FIG. 12 . The light-shielding by the touch pattern TP can be significantly decreased due to the openings TPW. By doing so, the bottom emission type display device  400  can be easily embodied. The openings TPW can be selectively applied to the previous embodiments. 
     The encapsulating unit EU can be formed on the display unit DU and can cover the display unit DU. The encapsulating unit EU can have various shapes, can be formed of various materials, and can decrease or prevent foreign substances, moisture, or outside air from penetrating into the display unit DU. The encapsulating unit EU can include an organic layer or an inorganic layer. Alternatively, the encapsulating unit EU can be a stack layer of at least one organic layer and at least one inorganic layer. 
     The encapsulating unit EU can have a layer shape as shown in  FIG. 10  or can have a cover shape as shown in  FIG. 3 . 
     Although not illustrated, in some embodiments, the encapsulating unit EU is an encapsulation substrate (not shown) that faces the substrate  401 , and the encapsulation substrate and the substrate  401  are bonded to each other by using a sealing member (not shown). 
     Although not illustrated, a protective layer (not shown) can be further formed on the touch pattern TP by using an insulating material. 
     In the display device  400  according to the present embodiment, the encapsulating unit EU is formed on one surface of the substrate  401 , and the touch pattern TP is formed on the other surface of the substrate  401 . By doing so, the touch pattern TP can be easily formed without affecting a characteristic of the display unit DU during forming thereof. 
     For example, the touch pattern TP is formed on a bottom surface of the substrate  401 , i.e., the touch pattern TP is formed on the other surface of the substrate  401  where the display unit DU is not formed, thus, when the touch pattern TP is formed, a degree of freedom with respect to a touch pattern forming process is increased. 
     Also, since the touch pattern TP is formed on the bottom surface of the substrate  401  and includes the transmissive conductive material, the bottom emission type display device  400  where an image is realized toward the substrate  401  can be easily embodied. 
     For example, when the touch pattern TP includes the light-shielding material and thus has a black-matrix function, a contrast of the display device  400  can be improved, and here, since the touch pattern TP has the openings TPW, a decrease of a luminescent efficiency can be sharply decreased. 
     Also, since the display device  400  does not require a separate panel or a substrate so as to realize a touch recognition function, the thickness of the display device  400  having the touch recognition function can be decreased, and a characteristic of a manufacturing procedure with respect to the display device  400  can be improved. 
       FIGS. 13 and 14  are diagrams illustrating a method of manufacturing a display device, according to an exemplary embodiment. 
     For convenience of description, in the present embodiment, it is assumed that the display device is the display device  200  of  FIG. 2 . Although not illustrated, the display devices of the previous embodiments other than the display device  200  of  FIG. 2  can also be applied to the method of the present embodiment. 
     Referring to  FIG. 13 , a structure excluding the touch pattern TP is formed. That is, the substrate  201 , the display unit DU, and the encapsulating unit EU are formed, so that the structure including the substrate  201 , the display unit DU, and the encapsulating unit EU is arranged. 
     Afterward, referring to  FIG. 14 , the touch pattern TP is formed on a surface of the substrate  201  that is opposite to the other surface of the substrate  201  on which the display unit DU is formed, so that the display device  200  is finally completed. 
     Referring to  FIGS. 13 and 14 , the substrate  201 , the display unit DU, and the encapsulating unit EU are formed. Then, the structure is flipped over, i.e., the surface of the substrate  201  opposite the other surface of the substrate  201  on which the display unit DU is formed faces upward, and then, a process of forming the touch pattern TP is performed. 
     However, the described technology is not limited thereto, thus, the structure including the substrate  201 , the display unit DU, and the encapsulating unit EU is formed and then the process of forming the touch pattern TP can be performed while the surface of the substrate  201  opposite the other surface of the substrate  201  on which the display unit DU is formed faces downward. 
     According to the method of manufacturing the display device of the present embodiment, after the display unit DU and the encapsulating unit EU are formed on the substrate  201 , the touch pattern TP is formed on the surface of the substrate  201  that is opposite to the other surface of the substrate  201  on which the display unit DU and the encapsulating unit EU are formed. By doing so, when the display unit DU and the encapsulating unit EU are formed, defect occurrence due to the process of forming the touch pattern TP can be fundamentally prevented, and when the touch pattern TP is formed, the process of forming the touch pattern TP can be performed on the surface of the substrate  201 , without consideration of the display unit DU and the encapsulating unit EU, so that an efficiency of the process of forming the touch pattern TP can be increased. 
     It should be understood that the exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should typically be considered as available for other similar features or aspects in other exemplary embodiments. 
     While the inventive technology has been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details can be made therein without departing from the spirit and scope as defined by the following claims.