Patent Publication Number: US-9905621-B2

Title: Organic EL display device

Description:
TECHNICAL FIELD 
     The present disclosure related to an organic EL display device. 
     BACKGROUND 
     Recently, an organic EL display device including an organic light-emitting element containing an organic electro-luminescence (EL) material has attracted attention as a display device. For example, an organic EL display device mounted on a mobile device such as a cellular phone includes a touch panel. Japanese Unexamined Patent Publication No. 2010-243930 discloses an organic EL display device that has an organic EL panel including a top-emission organic light-emitting element and a touch panel mounted thereon. 
     SUMMARY 
     In Japanese Unexamined Patent Publication No. 2010-243930, the organic EL panel and the touch panel are respectively formed from separate substrates. In this case, substrates for both the organic EL panel and the touch panel are needed for the organic EL display device. In Japanese Unexamined Patent Publication No. 2010-243930, integrated circuits for both the organic EL panel and the touch panel are used. Thus, the number of components of the conventional organic EL display device including a touch panel is larger than the number of components of an organic EL display device including no touch panel. 
     An organic EL display device according to an aspect of the present invention includes: a first substrate having transmissive properties; a touch electrode for a touch sensor, the touch electrode being provided on a main surface of the first substrate; an insulating film provided on the main surface and covering the touch electrode wherein the insulating film includes a first surface at the touch electrode-side and a second surface opposite to the first surface; an organic light-emitting element provided on the second surface of the insulating film; a second substrate provided facing the main surface of the first substrate; and an integrated circuit electrically connected with both the touch electrode and the organic light-emitting element. The touch electrode, the insulating film, and the organic light-emitting element are interposed between the first substrate and the second substrate. 
     In this organic EL display device, the touch electrode for a touch sensor is provided on the main surface of the first substrate, and the organic light-emitting element is provided on this main surface with the touch electrode and the insulating film interposed therebetween. With this configuration, the touch sensor and the organic light-emitting element do not need to be formed using separate substrates. The integrated circuit included in the organic EL display device is electrically connected with both the touch electrode and the organic light-emitting element. With this configuration, it is possible to use the integrated circuit common to both the touch sensor and the organic light-emitting element. Thus, the above-described organic EL display device can achieve a reduced number of components. 
     The above-described organic EL display device may further include a wiring terminal electrically connected with the integrated circuit, the wiring terminal may be provided overlapping part of the touch electrode with the insulating film interposed between the touch electrode and the wiring terminal, and the touch sensor and the integrated circuit may be electrically connected with each other through a capacitor constituted by the touch electrode, the insulating film, and the wiring terminal. With this configuration, for example, even when the insulating film is not provided with an opening so as not to bring the wiring terminal and the touch electrode into contact with each other through the opening, the touch electrode and the integrated circuit can be electrically connected with each other. In this case, a process of forming the opening in the insulating film can be omitted, and thus a cost of manufacturing the organic EL display device can be reduced. 
     The above-described organic EL display device may further include a wiring terminal electrically connected with the integrated circuit, the wiring terminal may be provided in touch with the touch electrode, and the wiring terminal may be connected with the touch electrode through an opening provided in the insulating film. In this case, the integrated circuit and the touch electrode can be electrically connected with each other through the wiring terminal in a reliable manner. 
     The organic light-emitting element does not need to overlap with an edge of the touch electrode in plan view. In this case, in plan view, coexistence of a region in which the organic light-emitting element overlaps with the touch electrode and a region in which the organic light-emitting element does not overlap with the touch electrode can be prevented. Accordingly, light emission unevenness of the organic light-emitting element due to the touch electrode can be reduced. 
     A plurality of the touch electrodes may be provided on the main surface of the first substrate, a plurality of the organic light-emitting elements may be provided on the insulating film, and each of the organic light-emitting elements may overlap with any one of the touch electrodes but with none of edges of the touch electrodes in plan view. In this case, even when the organic light-emitting elements are provided on the insulating film, no region in which the organic light-emitting elements overlap with none of the touch electrodes is formed. Accordingly, light emission unevenness occurring to each organic light-emitting element due to the touch electrodes can be reduced. 
     A plurality of the touch electrodes may be provided on the main surface of the first substrate, a plurality of the organic light-emitting elements may be provided on the insulating film, part of the organic light-emitting elements may overlap with any one of the touch electrodes but with none of edges of the touch electrodes in plan view, and rest of the organic light-emitting elements may overlap with none of the touch electrodes in plan view. In this case, none of the organic light-emitting elements partially overlaps with the touch electrodes in plan view. Thus, light emission unevenness due to the touch electrodes is reduced in both of the part of the organic light-emitting elements overlapping with any one of the touch electrodes, and the rest of the organic light-emitting elements overlapping with none of the touch electrodes. 
     The integrated circuit may be provided between the first substrate and the second substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic plan view illustrating part of an organic EL display device according to an embodiment; 
         FIG. 2  is a schematic cross-sectional view illustrating a main part of the organic EL display device according to the embodiment; 
         FIG. 3  is a schematic cross-sectional view for description of a connection between touch electrodes and an integrated circuit of a touch sensor in an organic EL display device according to a first modification; 
         FIG. 4  is a schematic plan view illustrating a relation between the touch electrodes and organic light-emitting elements of the touch sensor in the organic EL display device according to a second modification; and 
         FIG. 5  is a schematic plan view illustrating a relation between the touch electrodes and the organic light-emitting elements of the touch sensor in the organic EL display device according to a third modification. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, any identical elements or elements having an identical function are denoted by an identical reference sign, and any duplicate description will be omitted. 
     First, the configuration of an organic EL display device  1  according to the present embodiment will be described with reference to  FIGS. 1 and 2 . 
     As illustrated in  FIGS. 1 and 2 , the organic EL display device  1  is, for example, a passive matrix display device. The organic EL display device  1  includes a first substrate  2 , a touch sensor  3  provided on a main surface  2   a  of the first substrate  2 , a light-emitting region  4  defined on the touch sensor  3 , an integrated circuit  5  electrically connected with the touch sensor  3 , and a second substrate  6  provided facing the first substrate  2  with the touch sensor  3 , the light-emitting region  4 , and the integrated circuit  5  interposed therebetween. 
     The first substrate  2  is a transmissive substrate, and has a substantially rectangular shape in plan view. Thus, the main surface  2   a  of the first substrate  2 , and a main surface  2   b  facing the main surface  2   a  each have a substantially rectangular shape. The thickness of the first substrate  2  is, for example, 100 μm to 1000 μm. Examples of the first substrate  2  include a glass substrate, a ceramics substrate, and a flexible substrate (for example, a plastic substrate). In the present embodiment, a glass substrate is used as the first substrate  2 . A polarization film  8  configured to polarize light transmitting through the first substrate  2  is provided on the main surface  2   b . In the present embodiment, a plan view is a view in the normal direction of the main surface  2   a.    
     The touch sensor  3  is an electrostatic capacitive sensor configured to detect a conductive material (detection target) positioned on the main surface  2   b  of the first substrate  2 . The touch sensor  3  includes touch electrodes  11  to  18  provided on the main surface  2   a , and the integrated circuit  5 . In the touch sensor  3 , when a detection target comes close to the first substrate  2 , the integrated circuit  5  detects a change in capacitance due to at least one of the touch electrodes  11  to  18  and the detection target. Accordingly, the touch sensor  3  can detect the presence of any detection target in contact with the first substrate  2 . Description of the touch electrodes  11  to  18 , and description of a connection configuration between the touch electrodes  11  to  18  and the integrated circuit  5  will be given later. 
     As illustrated in  FIG. 2 , the touch electrode  11  of the touch sensor  3  is covered by an insulating film  21  provided on the main surface  2   a . The insulating film  21  is a transmissive and insulating film, and provided covering the main surface  2   a . The thickness of the insulating film  21  is, for example, 100 nm to 1000 nm. The insulating film  21  is, for example, a silicon oxide film (SiOx film). The insulating film  21  is formed on the main surface  2   a  by a chemical vapor deposition method (CVD method), the main surface being formed on the touch electrodes  11  to  18 , for example. Thus, the touch electrodes  11  to  18  are covered by the insulating film  21 . 
     The light-emitting region  4  is a region capable of generating light in the organic EL display device  1 , and is defined at a central part of the main surface  2   a  of the first substrate  2 . A plurality of organic light-emitting elements  31  disposed in matrix are provided in the light-emitting region  4 . The interval between the organic light-emitting elements  31  adjacent to each other in plan view is, for example, 10 μm to 50 μm. Illustration of, for example, a partition provided in the light-emitting region  4  is omitted. 
     Each organic light-emitting element  31  is an element configured to emit light when supplied with current, and as illustrated in  FIG. 2 , has a configuration in which an organic light-emitting layer  33  is interposed between a pair of electrodes  32  and  34 . The organic light-emitting element  31  is provided on a second surface  21   b  of the insulating film  21 , the second surface  21   b  being opposite to a first surface  21   a  of the insulating film  21 , and the first surface  21   a  being closer to the touch electrodes  11  to  18  than the second surface  21   b . In other words, the organic light-emitting element  31  is provided on a surface of the insulating film  21 , the surface being closer to the second substrate  6  than the other surface of the insulating film  21 . 
     The electrode  32  is a conductive layer functioning as an anode of the organic light-emitting element  31 , and is positioned closest to the first substrate  2 , in the organic light-emitting element  31 . The electrode  32  is a patterned transparent conductive layer. Examples of the material of the electrode  32  include indium tin oxide (ITO) and indium zinc oxide (IZO). The thickness of the electrode  32  is, for example, 100 nm to 500 nm. The electrode  32  is formed by, for example, a physical vapor deposition method (PVD method). 
     The organic light-emitting layer  33  is a layer containing at least organic compound (light-emitting material) that emits light through injection of an electron and a hole, and is provided on the electrode  32 . The organic compound may be low-molecular compound or high-molecular compound. The organic light-emitting layer  33  may include, in addition to the light-emitting layer containing a light-emitting material, an electron injection layer, an electron transport layer, a hole transport layer, a hole injection layer and the like. Light generated by the organic light-emitting layer  33  may be, for example, single-color light such as red light or blue light, or may be white light. When the organic light-emitting layer  33  generates white light, the organic light-emitting layer  33  may include a plurality of light-emitting layers configured to generate light in different colors. The thickness of the organic light-emitting layer  33  is, for example, 100 nm to 500 nm. The organic light-emitting layer  33  is formed by, for example, a dry method such as a vacuum evaporation method or a wet method such as ink jet. A fluorescence material or a phosphorescent material may be used as the light-emitting material. 
     The electrode  34  is a conductive layer functioning as a cathode of the organic light-emitting element  31 , and is provided on the organic light-emitting layer  33 . The electrode  34  includes, for example, a single or a plurality of light absorbing or light reflecting conductive layers. Aluminum, silver, or alkali-earth metal (such as magnesium or calcium) is used as the material (conductive material) of each conductive layer included in the electrode  34 . The thickness of the electrode  34  is, for example, 100 nm to 500 nm. The electrode  34  is formed by, for example, a PVD method. 
     The integrated circuit  5  is a circuit electrically connected with both the touch sensor  3  and the organic light-emitting elements  31 . The integrated circuit  5  is configured to control them, and is mounted outside of the light-emitting region  4  on the first substrate  2  in plan view. For example, various kinds of IC chips are used as the integrated circuit  5 . The integrated circuit  5  is electrically connected with the touch sensor  3  through wires  41  to  48  provided on the insulating film  21 . The integrated circuit  5  is electrically connected with the organic light-emitting elements  31  inside of the light-emitting region  4  through wiring regions  51  to  53  provided on the insulating film  21 . The wiring regions  51  to  53  are each a region in which a plurality of wires are provided. Details of the wires  41  to  48  will be described later. 
     The second substrate  6  is a substrate having a size substantially identical to the first substrate  2  in plan view. Thus, the second substrate  6  has a substantially rectangular shape in plan view. The second substrate  6  is provided facing the first substrate  2  with the touch electrodes  11  to  18 , the insulating film  21 , the organic light-emitting elements  31 , and the integrated circuit  5  interposed therebetween. In other words, the touch electrodes  11  to  18 , the insulating film  21 , the organic light-emitting elements  31 , and the integrated circuit  5  are provided between the first substrate  2  and the second substrate  6 . Examples of the second substrate  6  include a glass substrate, a ceramics substrate, and a flexible substrate (for example, a plastic substrate or a stainless-steel substrate). For example, the second substrate  6  is bonded to the first substrate  2  by adhesive having a frame shape and being provided around the organic light-emitting elements  31 . Accordingly, the organic light-emitting elements  31  are sealed by the first substrate  2 , the second substrate  6 , and the adhesive. 
     A flexible printed circuit (FPC)  7  for connection with an external device is attached to the organic EL display device  1 . The flexible printed circuit  7  is electrically connected with the integrated circuit  5  through a wiring region  54  provided on the insulating film  21 . Similarly to the wiring regions  51  to  53 , the wiring region  54  is a region in which a plurality of wires are provided, and is formed simultaneously with the wiring regions  51  to  53 . 
     The following describes the touch electrodes  11  to  18 . The touch electrodes  11  to  18  are patterned transparent conductive layers, and disposed in matrix on the first substrate  2 , respectively. The touch electrodes  11  to  14  and the touch electrodes  15  to  18  are sequentially arrayed in a longitudinal direction of the main surface  2   a . The touch electrodes  11  to  14  are provided further away from the integrated circuit  5  than the touch electrodes  15  to  18 . The touch electrodes  11  to  18  are provided separately from each other. The touch electrodes  11  to  18  are each independently electrically connected with the integrated circuit  5 . Accordingly, the integrated circuit  5  can detect the change in capacitance at each of the touch electrodes  11  to  18 , and thus can detect the position of the detection target. Examples of the material of the touch electrodes  11  to  18  include ITO and IZO. The touch electrodes  11  to  18  are formed by, for example, a PVD method. As described above, the touch electrodes  11  to  18  are transparent conductive layers, and thus light generated by the organic light-emitting elements  31  is externally emitted through the touch sensor  3  and the first substrate  2 . 
     The touch electrode  11  includes a detection region  11   a  configured to detect the detection target, and a connection region  11   b  for connecting the detection region  11   a  with the integrated circuit  5 . The detection region  11   a  has a substantially rectangular shape in plan view, and part or all of the detection region  11   a  overlaps with the light-emitting region  4 . The connection region  11   b  extends on the first substrate  2  such that an end part of the connection region  11   b  overlaps with the wire  41  in plan view. Similarly to the touch electrode  11 , the touch electrodes  12  to  18  include detection regions  12   a  to  18   a  and connection regions  12   b  to  18   b , respectively. The detection regions  12   a  to  18   a  each have a substantially rectangular shape in plan view, and overlap with the light-emitting region  4 . The connection regions  12   b  to  18   b  extend on the first substrate  2  such that end parts of the connection regions  12   b  to  18   b  overlap with the wires  42  to  48 , respectively, in plan view. The interval between the detection regions adjacent to each other on the light-emitting region  4  is, for example, 10 μm approximately, and is not larger than the interval between the organic light-emitting elements  31  adjacent to each other. The sizes of the detection regions  11   a  to  18   a  of the touch electrodes  11  to  18  are each substantially same as the size of each region obtained by dividing the light-emitting region  4  into eight (two rows by four columns), and the touch electrodes  11  to  18  are provided such that the detection regions  11   a  to  18   a  each overlap with any one of these divided regions. 
     The following describes connection between the touch electrodes  11  to  18  for the touch sensor  3  and the integrated circuit  5 . As described above, the integrated circuit  5  is electrically connected with the touch sensor  3  through the wires  41  to  48 . The integrated circuit  5  is electrically connected with the touch electrode  11  through the wire  41 . The wire  41  includes a terminal part (wiring terminal)  41   a  overlapping with the connection region  11   b  of the touch electrode  11 , and a routing part  41   b  connecting the integrated circuit  5  and the terminal part  41   a.    
     The terminal part  41   a  has a substantially rectangular shape in plan view and is provided overlapping with the end part of the connection region  11   b  with the insulating film  21  interposed therebetween. Thus, a capacitor  61  is formed from the terminal part  41   a , the insulating film  21 , and the connection region  11   b , and the touch electrode  11  and the integrated circuit  5  are electrically connected with each other through the wire  41  and the capacitor  61 . 
     Similarly to the wire  41 , the wires  42  to  48  include terminal parts  42   a  to  48   a  and routing parts  42   b  to  48   b , respectively. The terminal parts  42   a  to  48   a  each have a substantially rectangular shape in plan view, and are provided overlapping with the connection regions  12   b  to  18   b , respectively, with the insulating film  21  interposed therebetween. Accordingly, the touch electrodes  12  to  18  are electrically connected with the wires  42  to  48 , respectively, through capacitors. 
     The terminal part  41   a ,  42   a ,  45   a , and  46   a  are provided near one of the four corners of the main surface  2   a  outside of the light-emitting region  4 . The terminal parts  43   a ,  44   a ,  47   a , and  48   a  are provided near another one of the four corners of the main surface  2   a  outside of the light-emitting region  4 . The wires  41  to  48  are formed simultaneously with the electrode  32  of each organic light-emitting element  31 . Thus, the wires  41  to  48  each include a transparent conductive layer. The wires  41  to  48  may each have a laminated structure. In this case, the wires  41  to  48  each include, for example, a transparent conductive layer formed simultaneously with the electrode  32  and a conductive layer formed simultaneously with the electrode  34 . Accordingly, the resistance values of the wires  41  to  48  can be decreased. 
     In the organic EL display device  1  according to the present embodiment described above, the touch electrodes  11  to  18  for the touch sensor  3  are provided on the main surface  2   a  of the first substrate  2 , and each organic light-emitting element  31  is provided on the main surface  2   a  with the touch electrodes  11  to  18  and the insulating film  21  interposed therebetween. Thus, it is not necessary to form the touch sensor  3  and the organic light-emitting element  31  using separate substrates. The integrated circuit  5  included in the organic EL display device  1  is electrically connected with both the touch electrodes  11  to  18  and the organic light-emitting elements  31 . Accordingly, it is possible to use the integrated circuit  5  common to both the touch sensor  3  and the organic light-emitting elements  31 . Thus, the organic EL display device  1  can achieve a reduced number of components. 
     According to the present embodiment, the touch sensor  3  and the organic light-emitting elements  31  are formed on the first substrate  2 . Thus, for example, a process of attaching a substrate on which a touch sensor is provided to a substrate on which an organic light-emitting element is provided can be omitted. Accordingly, in the present embodiment, it is possible to avoid error in a bonding position, an insufficient bonding intensity, and generation of a defective product due to, for example, incorporation of an air bubble or a foreign object, which can be caused by a process of attaching substrates to each other. In addition, in the present embodiment, the integrated circuit  5  is electrically connected with both the touch sensor  3  and the organic light-emitting elements  31 . This facilitates synchronous control of the touch sensor  3  and the organic light-emitting elements  31  by the integrated circuit  5 . 
     The organic EL display device  1  includes the terminal part  41   a  electrically connected with the integrated circuit  5  and provided overlapping with the connection region  11   b  of the touch electrode  11  with the insulating film  21  interposed therebetween. The touch electrode  11  and the integrated circuit  5  are electrically connected with each other through the capacitor  61  including the connection region  11   b  of the touch electrode  11 , the insulating film  21 , and the terminal part  41   a . Accordingly, for example, even when the insulating film  21  is not provided with an opening so as not to bring the terminal part  41   a  and the connection region  11   b  into contact with each other through the opening, the touch electrode  11  and the integrated circuit  5  can be electrically connected with each other. In this case, a process of forming the opening in the insulating film  21  can be omitted, and thus a cost of manufacturing the organic EL display device  1  can be reduced. 
     The following describes a first modification of the present embodiment with reference to  FIG. 3 . As illustrated in  FIG. 3 , an opening  21   c  through which the connection region  11   b  is exposed, and an opening  21   d  through which the connection region  12   b  is exposed are formed in the insulating film  21 . With this configuration, the terminal part  41   a  is connected with the connection region  11   b  through the opening  21   c , and the terminal part  42   a  is connected with the connection region  12   b  through the opening  21   d . In the first modification, openings are formed at part of the insulating film  21 , the part overlapping with end parts of the connection regions  13   b  to  18   b . Thus, the connection regions  13   b  to  18   b  are connected with the terminal parts  43   a  to  48   a , respectively, through the corresponding openings. In this case, the integrated circuit  5  and the touch sensor  3  can be electrically connected through the terminal parts  41   a  to  48   a  in a reliable manner. 
     The following describes a second modification of the present embodiment with reference to  FIG. 4 . As illustrated in  FIG. 4 , each of the organic light-emitting elements  31  disposed in matrix overlaps with any one of the touch electrodes  11 ,  12 ,  15 , and  16  but with none of edges of the touch electrodes  11 ,  12 ,  15 , and  16  in plan view. In other words, each of the organic light-emitting elements  31  completely overlaps with any one of the touch electrodes  11 ,  12 ,  15 , and  16  in plan view. In the second modification, any organic light-emitting element  31  overlapping with any one of the touch electrodes  13 ,  14 ,  17 , and  18  overlaps with none of edges of the touch electrodes  11  to  18 . 
     In this case, in plan view, coexistence of a region in which the organic light-emitting elements  31  overlap with any one of the touch electrodes  11  to  18  and a region in which the organic light-emitting elements  31  overlap with none of the touch electrodes  11  to  18  can be prevented. Accordingly, in the second modification, light emitted by the organic light-emitting elements  31  toward the first substrate  2  passes through any one of the touch electrodes  11  to  18 , and thus unevenness of the light emitted by the organic light-emitting elements  31  due to the touch electrodes  11  to  18  can be reduced. 
     The following describes a third modification of the present embodiment with reference to  FIG. 5 . As illustrated in  FIG. 5 , part of the organic light-emitting elements  31  disposed in matrix overlaps with any one of the touch electrodes  15  and  16  in plan view but with none of the edges of the touch electrodes  15  and  16 . The rest of the organic light-emitting elements  31  overlaps with none of the touch electrodes  15  and  16  in plan view. In other words, the rest of the organic light-emitting elements  31  completely overlaps with none of the touch electrodes in plan view. 
     In the third modification, similarly to the second modification, each of the organic light-emitting elements  31  overlaps with none of the edges of the touch electrodes  11  to  18 . In other words, none of the organic light-emitting elements  31  partially overlap with the touch electrodes  11  to  18  in plan view. Thus, the light emission unevenness due to the touch electrodes is reduced in both of the part of the organic light-emitting elements  31  overlapping with any one of the touch electrodes  11  to  18 , and the rest of the organic light-emitting elements  31  overlapping with none of the touch electrodes  11  to  18 . In addition, both of a region in which the touch sensor  3  functions and a region in which the touch sensor  3  does not function can be provided in the light-emitting region  4  of the organic EL display device  1 . 
     In the second modification and the third modification described above, the integrated circuit  5  does not necessarily need to be electrically connected with both the touch sensor  3  and the light-emitting region  4 . In this case, a substrate on which the touch sensor  3  and the integrated circuit are provided and a substrate on which the organic light-emitting elements  31  and any other integrated circuit are provided may be different substrates. In such a case, advantages of the second modification and the third modification can also be sufficiently obtained. 
     An organic EL display device according to the present invention is not limited to the above-described embodiment and modifications, but any other various modifications are possible. For example, in the above-described embodiment and modifications, the integrated circuit  5  is provided between the first substrate  2  and the second substrate  6 , but the present invention is not limited thereto. For example, the integrated circuit  5  may be integrated with the flexible printed circuit  7  and does not need to be provided between the first substrate  2  and the second substrate  6 . 
     In the above-described embodiment and modifications, the organic EL display device  1  is not limited to a passive matrix display device. For example, the organic EL display device  1  may be an active matrix display device. In this case, for example, a transistor corresponding to each organic light-emitting element  31  is provided to the light-emitting region  4 . 
     In the above-described embodiment and modifications, both of the electrode  34  and the second substrate  6  may be transmissive. In this case, the organic EL display device  1  can be a see-through display device. 
     In the above-described embodiment and modifications, both of the first substrate  2  and the second substrate  6  may be flexible. In this case, the organic EL display device  1  can be a flexible display device. In addition, the first substrate  2  and the second substrate  6  are each not limited to a substantially rectangular shape in plan view. For example, the first substrate  2  and the second substrate  6  may each have a polygonal shape or a substantially circular shape in plan view. 
     In the above-described embodiment and modifications, a touch sensor of another scheme may be used as the touch sensor  3 . For example, a projected capacitive touch sensor may be used. In this case, each touch electrode may have a laminated structure. 
     This application is based on Japanese Patent Application serial no. 2016-023841 filed with Japan Patent Office on Feb. 10, 2016, the entire contents of which are hereby incorporated by reference.