Abstract:
Disclosed is a method for manufacturing a flexible organic light-emitting diode (OLED) display component which includes steps of: forming a ferromagnetic material layer on a surface of a flexible substrate; and abutting the ferromagnetic material layer against a flat bearing surface, and applying a magnetic pull force directing to the bearing surface on the ferromagnetic material layer. Drawn by the magnetic pull force, the ferromagnetic material layer abuts closely against the flat bearing surface, smoothing out the flexible substrate, and meanwhile fixing the flexible substrate on the bearing surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the priority of Chinese patent application CN201510383409.0, entitled “Method for manufacturing flexible OLED display component” and filed on Jul. 02, 2015, the entirety of which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a method for manufacturing organic light-emitting diode (OLED) display component, and in particular, to a method for manufacturing flexible OLED display component. 
       TECHNICAL BACKGROUND 
       [0003]    Organic light-emitting diode (OLED) display components possess excellent characteristics, such as self-luminescence, full-color display, high brightness, high contrast ratio, low voltage, low power consumption, light and thin structure, high luminous efficiency, quick response, wide viewing angle, monolithic structure, simple manufacturing process, low cost, etc. 
         [0004]    Flexible OLED display components are an organic thin-film electro-fluorescence component with a flexible structure. A Flexible OLED display component comprises a flexible substrate and organic light-emitting diodes, the flexible substrate being a base, and the thin-film organic light-emitting diodes being provided on the flexible substrate. 
         [0005]    In the process of manufacturing flexible OLED display components, since the flexible substrate bends easily, the flexible substrate has to be adhered to a flat glass substrate so as to be supported by the glass substrate. In this case, the flexible substrate can keep flat during the process of forming organic light-emitting diodes thereon. 
         [0006]    However, after being manufactured, the flexible OLED display component has to be peeled off the glass substrate. Since the flexible substrate and the glass substrate are held together with super glue, it is very hard to peel the flexible OLED display component off the glass substrate. Besides, before peeling the flexible OLED display component off the glass substrate, the flexible OLED display component and the glass substrate have to be cut simultaneously so that the flexible OLED display component can have a predetermined size. Thus, a glass substrate is consumed each time a flexible OLED display component is manufactured. 
       SUMMARY OF THE INVENTION 
       [0007]    The objective of the present disclosure is to solve the technical problem that in the process of manufacturing a flexible organic light-emitting diode (OLED) display components, it is hard to keep the flexible substrate fixed and flat. 
         [0008]    Directed by the above technical problem, the present disclosure provides a method for manufacturing flexible OLED display component, which comprises steps of: forming a ferromagnetic material layer on a surface of a flexible substrate; and abutting the ferromagnetic material layer against a flat bearing surface, and applying a magnetic pull force directing to the bearing surface on the ferromagnetic material layer. 
         [0009]    In one embodiment, the bearing surface is provided with a magnet on a surface thereof opposite to the ferromagnetic material layer, so that the magnetic pull force can be exerted on the ferromagnetic material layer by the magnet. 
         [0010]    In one embodiment, the magnet is an electromagnet. 
         [0011]    In one embodiment, the bearing surface is a surface of a cooling plate of a vacuum evaporator. 
         [0012]    In one embodiment, the ferromagnetic material layer has an even thickness. 
         [0013]    In one embodiment, the magnetic pull force is evenly distributed on the ferromagnetic material layer. 
         [0014]    In one embodiment, the magnetic pull force is perpendicular to the bearing surface. 
         [0015]    In one embodiment, the method further comprises forming organic light-emitting diodes on the other surface of the flexible substrate. 
         [0016]    In one embodiment, the flexible OLED display component is a bottom-emitting flexible OLED display component, and after all the organic light-emitting diodes are formed, the ferromagnetic material layer is removed. 
         [0017]    In one embodiment, the flexible OLED display component is a top-emitting flexible OLED display component. 
         [0018]    The ferromagnetic material layer interacts with the magnetic field, so that it is acted thereupon by a magnetic pull force directing to the bearing surface, in which case, the ferromagnetic material layer is attracted onto the bearing surface. When the ferromagnetic material layer abuts against the flat bearing surface, the flexible substrate is smoothed out. In addition, since the ferromagnetic material layer abuts against the flat bearing surface, the positions of the two are relatively fixed, thereby fixing the flexible substrate on the bearing surface. Furthermore, since magnitude of the magnetic pull force can be easily controlled, it will be easy to remove the flexible substrate from the bearing surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A more detailed description on the present disclosure will be given below based on the embodiments and with reference to the accompanying drawings. 
           [0020]      FIG. 1  shows a flow chart of a method for manufacturing flexible OLED display component according to an embodiment of the present disclosure; 
           [0021]      FIG. 2  schematically shows the structure of a vacuum evaporator according to an embodiment of the present disclosure; and 
           [0022]      FIG. 3  schematically shows the structure of a flexible OLED display component according to an embodiment of the present disclosure. 
       
    
    
       [0023]    In the accompanying drawings, the same components are indicated by the same reference signs, and the drawings are not drawn to scale. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    The present disclosure will be explained further in detail with reference to the accompanying drawings. 
         [0025]    As shown in  FIG. 1 , the present embodiment introduces a method for manufacturing a flexible organic light-emitting diode (OLED) display component  100 , which comprises the following steps. 
         [0026]    In step S 10 , a first conducting layer is formed on a surface, namely a first surface, of the flexible substrate  1 . The first conducting layer is patterned to form a plurality of parallel anode lines  31 . 
         [0027]    The flexible substrate  1  can be a resin substrate. The first conducting layer is usually formed on the first surface of the flexible substrate  1  by a physical vapor deposition method which can be, for example, sputter deposition, or vacuum evaporation. The first conducting layer is usually made of a transparent conducting material, and can be, for example, an indium tin oxide film. The first conducting layer can be photoetched to form a plurality of anode lines  31  that are parallel to each other. Two neighboring anode lines  31  are spaced from each other. The first conducting layer usually serves as an anode of the organic light-emitting diode. 
         [0028]    Preferably, after the first conducting layer is formed, a surface of the first conducting layer opposite to the flexible substrate  1  is treated, so as to improve performance function of the first conduction layer, thereby decreasing the hole injection barrier. The surface treatment method can be, for example, ultraviolet-ozone treatment, plasma treatment or the like. The surface treatment is able to reduce the surface roughness of the first conducting layer. 
         [0029]    In step S 20 , an organic thin film is formed on the first conducting layer. In the present embodiment, the organic thin film is formed by evaporation method, which specifically comprises steps S 21 , S 22 , S 23 , S 24 , and S 25 . 
         [0030]    In step S 21 , a ferromagnetic material layer  2  is formed on a second surface of the flexible substrate  1  (i.e., a surface opposite to the first surface) by, for example, physical vapor deposition method. The ferromagnetic material layer  2  is made of a material comprising ferromagnetic material which can be, for example, iron, cobalt, or nickel. The physical vapor deposition method can be, for example, sputter deposition, or vacuum evaporation. The ferromagnetic material layer  2  is very thin, and therefore has a very low strength, in which case, the flexible substrate  1  to which the ferromagnetic material layer  2  adheres also has a small change rate of strength. Preferably, the ferromagnetic material layer  2  has an even thickness. In addition, the ferromagnetic material layer  2  can also be formed on the second surface by coating. 
         [0031]    In step S 22 , the flexible substrate  1  is spread smoothly on a flat bearing surface, the second surface of the flexible substrate  1  facing the bearing surface. A magnetic pull force directing to the bearing surface is exerted on the ferromagnetic material layer  2 , so that the flexible substrate  1  is spread out flat and is fixed relative to the bearing surface. The bearing surface is usually a bearing surface of a loading table of processing equipment. 
         [0032]    As shown in  FIG. 2 , the vacuum evaporator  10  comprises a vacuum chamber  6  which is provided therein with a loading board  4 , an electromagnet  5 , and an evaporator source  7 . The loading board  4  serves as a loading table of the vacuum evaporator  10 , and is structured substantially to have a shape of a plate, and is disposed horizontally. A surface of the loading board  4  facing downward is the bearing surface  41 . The electromagnet  5  is provided over the loading board  4 . The evaporator source  7  is provided right under the loading board  4 , with an opening thereof facing upward. 
         [0033]    When the electromagnet  5  is activated, the flexible substrate  1  is spread out on the bearing surface  41 , the second surface of the flexible substrate  1  facing upward. A magnetic pull force from the electromagnet  5  and directing to the loading board  4  is exerted on the ferromagnetic material layer, thereby fixing the flexible substrate  1  on the bearing surface  41  of the loading board  4 . Since the bearing surface  41  is flat, the flexible substrate  1  is spread out flat on the bearing surface  41  when the ferromagnetic material layer and the bearing surface  41  stick to each other. Obviously, the electromagnet  5  herein can be substituted with a permanent magnet which is, preferably, magnetic steel. 
         [0034]    Preferably, the electromagnet  5  is provided right above the ferromagnetic material layer  2 , so that the magnetic pull force is directed as being perpendicular to the bearing surface  41 , which enables the flexible substrate  1  to be fixed more firmly on the bearing surface  41 . 
         [0035]    Preferably, the loading board  4  is a cooling plate of the vacuum evaporator  10 . The flexible substrate  1  transmits heat to the cooling plate, thereby preventing the flexible substrate  1  from expanding or becoming soft due to the heat generated during the evaporation. 
         [0036]    Preferably, a plurality of the electromagnets  5  is provided, and is distributed evenly over the loading board  4 . Therefore, the magnetic pull force acted upon the ferromagnetic material layer  2  can be evenly distributed on the ferromagnetic material layer  2 , which enables the flexible substrate  1  to be spread out more flat. 
         [0037]    In step S 23 , a hole transport layer is formed on the first conducting layer. The hole transport layer is patterned to form a plurality of hole transport blocks  32 , which covers the plurality of anode lines  31  and is arranged in the form of an array. 
         [0038]    In the present embodiment, a hole transport material is evaporated to form a hole transport layer on the first conducting layer. Specifically, a first evaporation mask  8  is provided between the first conducting layer and the evaporator source  7 . The first evaporation mask  8  is provided thereon with meshes arranged in the form of a matrix. The meshes are aligned with the anode lines  31 . After the hole transport material is put into the evaporator source  7 , the vacuum chamber  6  is evacuated. Then, the evaporator source  7  is activated to heat the hole transport material, so that the hole transport material can be changed into gas. The gaseous hole transport material passes through the meshes of the first evaporation mask  8 , and deposits on the anode lines  31 , forming a plurality of hole transport blocks  32  on the plurality of anode lines  31 . The plurality of hole transport blocks  32  is arranged in the form of a matrix. The hole transport material can be m-MTDATA. 
         [0039]    In step S 24 , an luminescent layer is formed on the hole transport layer. The luminescent layer is patterned to form a plurality of luminescent blocks  33  which covers the hole transport blocks  32 , each of the luminescent blocks  33  corresponding to a respective hole transport block  32 . 
         [0040]    In the present embodiment, a luminescent material is evaporated to form a luminescent layer on the hole transport layer. Specifically, a first evaporation mask  8  is provided between the hole transport layer and the evaporator source  7 . The meshes of the first evaporation mask  8  are aligned with the hole transport blocks  32 . After the organic luminescent material is put into the evaporator source  7 , the vacuum chamber  6  is evacuated. Then, the evaporator source  7  is activated to heat the organic luminescent material, so that the organic luminescent material can be changed into gas. The gaseous organic luminescent material passes through the meshes of the first evaporation mask  8 , and deposits on hole transport blocks  32 , forming a plurality of luminescent blocks  33 . Each of the luminescent blocks  33  covers a respective hole transport block  32 . Thus, the plurality of luminescent blocks  33  is also arranged in the form of a matrix. The organic luminescent material can be an organometallic complex, which can be, for example, Alq3 or Gaq3. 
         [0041]    In step S 25 , an electron transport layer is formed on the luminescent layer. The electron transport layer is patterned to form a plurality of electron transport blocks  34 , which covers the luminescent blocks  33 , each of the electron transport blocks  34  corresponding to a respective luminescent block  33 . 
         [0042]    In the present embodiment, an electron transport material is evaporated to form an electron transport layer on the luminescent layer. Specifically, a first evaporation mask  8  is provided between the luminescent layer and the evaporator source  7 . The meshes of the first evaporation mask  8  are aligned with luminescent blocks  33 . After the electron transport material is put into the evaporator source  7 , the vacuum chamber  6  is evacuated. Then, the evaporator source  7  is activated to heat the electron transport material, so that the electron transport material can be changed into gas. The gaseous electron transport material passes through the meshes of the first evaporation mask  8 , and deposits on the luminescent blocks  33 , forming a plurality of electron transport blocks  34 , which is also arranged in the form a matrix. The electron transport material can be 1, 3, 4-oxadiazole. 
         [0043]    In step S 30 , a second conducting layer is formed on the electron transport layer. The second conducting layer is patterned to form a plurality of cathode lines  35 , the cathode lines  35  being parallel to one another but perpendicular to the anode lines  31 . Each of the cathode lines  35  covers a plurality of electron transport blocks  34 . Two neighboring cathode lines  35  are spaced from each other. 
         [0044]    A second evaporation mask  9  is provided between the electron transport layer and the evaporator source  7 . A mask of cathode lines  35  is parallel to the flexible substrate  1 . The mask of cathode lines  35  is provided thereon with meshes having the patterns of the cathode lines  35 . After a metal material is put into the evaporator source  7 , the vacuum chamber  6  is evacuated. Then, the evaporator source  7  is activated to heat the metal material, so that the metal material can be changed into gas. The metal material can be a magnesium-silver alloy. The gaseous metal material passes through the meshes of the second evaporation mask  9 , and deposits on the electron transport layer, forming cathode lines  35  which are connected to a plurality of electron transport blocks  34 . 
         [0045]    When step S 30  is completed, a plurality of organic light-emitting diodes  3  arranged in the form of a matrix is formed on the first surface of the flexible substrate  1 . As shown in  FIG. 3 , each of the organic light-emitting diodes  3  includes an anode line  31 , a hole transport block  32 , a luminescent block  33 , an electron transport block  34 , and a cathode line  35 , which are stacked in order. 
         [0046]    In step S 40 , the flexible substrate  1  is removed from the bearing surface  41 . 
         [0047]    The ferromagnetic material layer attaches to the bearing surface  41  under the influence of the magnetic pull force. Therefore, the flexible substrate  1  can be easily removed from the bearing surface  41  by operator. If the magnetic pull force is generated by interaction between the ferromagnetic material layer and the electromagnets  5 , it can be eliminated by switching off the electromagnets  5  prior to step S 40 . Thus, it will be much easier to remove the flexible substrate  1  from the bearing surface  41 . Of course, the magnetic pull force can also be decreased by enlarging the distance between the electromagnet and the ferromagnetic material layer  2 . 
         [0048]    In step S 50 , the ferromagnetic material layer  2  is removed. 
         [0049]    The ferromagnetic material layer  2  can be removed through being corroded by an etching solution. The etching solution can be a strong acid such as diluted hydrochloric acid, or diluted sulphuric acid. The flexible OLED display component  100  can be a bottom-emitting flexible OLED display component. Therefore, when the light emitted by the organic light-emitting diodes  3  has to exit by passing through the flexible substrate, the ferromagnetic material layer  2  should be removed. 
         [0050]    In a preferred embodiment, the flexible OLED display component  100  is a top-emitting flexible OLED display component. The direction of the light emitted by the top-emitting flexible OLED display component is opposite to the ferromagnetic material layer  2 . In this case, step S 50  can be omitted when a top-emitting flexible OLED display component is manufactured. Therefore, the method is particularly suitable for manufacturing a top-emitting flexible OLED display component. 
         [0051]    In a preferred embodiment, step S 21  is first performed to form a ferromagnetic material layer  2  on a surface of the flexible substrate  1 , and then step S 10  is performed to form a first conducting layer on the other surface of the flexible substrate  1 . 
         [0052]    When step S 10  is performed, the flexible substrate  1  is spread out flat on the flat bearing surface by using the magnetic pull force, the ferromagnetic material layer  2  abutting against the bearing surface. Then, a first conducting layer is formed on a surface of the flexible substrate  1  opposite to the ferromagnetic material layer  2  by means of sputter deposition, or vacuum evaporation. 
         [0053]    In a preferred embodiment, steps S 23 , S 24 , S 25 , and S 30  can be performed on different equipment, which can be several vacuum evaporators  10 , so that layers formed in subsequent steps will not be polluted by the remnant of the formed layers left in the equipment from a previous step. 
         [0054]    Since steps S 23 , S 24 , S 25 , and S 30  are performed on different equipment, when these steps are performed in sequence, steps S 40  and S 22  are performed repeatedly between two neighboring steps among S 23 , S 24 , S 25 , and S 30 . In this case, the flexible substrate  1  can be taken off from one piece of equipment and then be fixed on another piece of equipment. This process is simple and easy to operate. 
         [0055]    The above details are only descriptions on preferred embodiments of the present disclosure. Any improvements on the implementing forms or substitutions of the components thereof with equivalents can be made or done without departing from the scope of the present disclosure. It should be noted that as long as there is no structural conflict, any of the embodiments and any of the technical features thereof may be combined with one another. The present disclosure is not limited to any disclosed embodiment, and comprises all technical solutions falling within the scope of the present disclosure.