Patent Publication Number: US-11398538-B2

Title: Light emitting diode display device and multi-screen display device using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/793,155 filed on Oct. 25, 2017, which claims the benefit and priority filing date of the Korean Patent Application No. 10-2016-0184458 filed on Dec. 30, 2016, which is hereby incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a light emitting diode display device and a multi-screen display device using the same. 
     Description of the Related Art 
     Display devices are being widely used as a display screen of notebook computers, tablet computers, smartphones, portable display devices, and portable information devices in addition to a display screen of television (TVs) and monitors. 
     LCD devices and organic light emitting display devices display an image by using thin film transistors (TFTs) as switching elements. Since the LCD devices cannot self-emit light, the LCD devices display an image by using light emitted from a backlight unit which is disposed under a liquid crystal display panel. Since the LCD devices include a backlight unit, a design of the LCD devices is limited, and luminance and a response time are reduced. Since the organic light emitting display devices include an organic material, the organic light emitting display devices are vulnerable to water, causing a reduction in reliability and lifetime. 
     Recently, research and development on light emitting diode display devices including a micro light emitting device are being done. The light emitting diode display devices have high image quality and high reliability, and thus, are attracting much attention as next-generation display devices. 
     A related art light emitting diode display device is manufactured by transferring a micro light emitting device onto a thin film transistor (TFT) array substrate, and due to a transfer process time taken in a transfer process for the micro light emitting device, current transfer technology is more advantageous to display devices having a relatively large size than panels having a relatively small size. 
     However, in the related art light emitting diode display device, a pad part for applying signals is provided in an edge of the TFT array substrate, and due to an instrument for covering the pad part, a bezel area increases. 
     Moreover, in a case where the related art light emitting diode display device is manufactured to have a large size, the number of pixels increases, and for this reason, a transfer error rate of a micro light emitting device increases, causing a reduction in productivity. In order to solve such a problem, research and development are being recently done on multi-screen devices which realize a large-size screen and are implemented by connecting two or more light emitting diode display devices having a relatively small size. However, in the multi-screen devices, due to a bezel area of each of the two or more light emitting diode display devices, a seam (or a boundary portion) exists between display devices coupled to each other. When displaying one image on a whole screen, the boundary portion causes a sense of discontinuity of the whole screen, causing a reduction in degree of viewing immersion of a user. 
     BRIEF SUMMARY 
     Accordingly, the present disclosure is directed to provide a light emitting diode display device and a multi-screen display device using the same that substantially obviate one or more problems due to limitations and disadvantages of the related art. 
     An aspect of the present disclosure is directed to provide a light emitting diode display device and a multi-screen display device using the same, which include a reduced or minimized bezel area. 
     Another aspect of the present disclosure is directed to provide a multi-screen display device in which a boundary portion between adjacent display devices is reduced or minimized. 
     Additional advantages and features of the disclosure will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the disclosure. The objectives and other advantages of the disclosure may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, there is provided a light emitting diode display device including a substrate including a first display area and a second display area surrounding the first display area, a plurality of first unit pixels provided in the first display area and each including a plurality of subpixels each including a micro light emitting device, and a plurality of second unit pixels provided in the second display area overlapping an edge of the substrate and each including a plurality of subpixels and having a size less than a size of each of the plurality of first unit pixels. 
     The plurality of first unit pixels may be arranged at a reference pixel pitch, and a distance between a center portion of each of the plurality of second unit pixels and an outer surface of the substrate may be half or less of the reference pixel pitch. 
     In another aspect of the present disclosure, there is provided a multi-screen display device including a plurality of screen modules each including a light emitting diode display device and a plurality of module coupling members coupling side surfaces of the plurality of screen modules, wherein the light emitting diode display device including a substrate including a first display area and a second display area surrounding the first display area, a plurality of first unit pixels provided in the first display area and each including a plurality of subpixels each including a micro light emitting device, and a plurality of second unit pixels provided in the second display area overlapping an edge of the substrate and each including a plurality of subpixels and having a size less than a size of each of the plurality of first unit pixels. 
     A maximum distance between second unit pixels of two screen modules which are adjacent to each other with one of the plurality of module coupling members therebetween may be equal to or less than a reference pixel pitch of a first unit pixel, and the reference pixel pitch may be a distance between center portions of two adjacent first unit pixels. 
     It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure. In the drawings: 
         FIG. 1  is a plan view of a light emitting diode display device according to an embodiment of the present disclosure; 
         FIG. 2  is a plan view illustrating a rear surface of a substrate illustrated in  FIG. 1 ; 
         FIG. 3  is a diagram for describing a configuration of a unit pixel according to an embodiment illustrated in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view for describing a structure of one subpixel illustrated in  FIG. 3 ; 
         FIG. 5  is a cross-sectional view for describing a structure of a micro light emitting device illustrated in  FIG. 4 ; 
         FIG. 6  is a plan view for describing a concave portion provided in a unit pixel according to an embodiment of the present disclosure; 
         FIG. 7  is a cross-sectional view taken along line I-I′ illustrated in  FIG. 6 ; 
         FIG. 8  is a diagram for describing an alternate embodiment of a concave portion according to an embodiment of the present disclosure; 
         FIG. 9  is a plan view for describing an alternate embodiment of a concave portion according to an embodiment of the present disclosure; 
         FIG. 10  is a diagram for describing a routing line of a light emitting diode display device illustrated in  FIGS. 2 and 7 ; 
         FIGS. 11A to 11C  are diagrams for describing a method of manufacturing a plurality of first routing lines illustrated in  FIG. 10 ; 
         FIGS. 12 and 13  are cross-sectional views taken along line I-I′ illustrated in  FIG. 6 ; 
         FIG. 14  is a diagram for describing a multi-screen display device according to an embodiment of the present disclosure; 
         FIG. 15  is a cross-sectional view taken along line II-II′ illustrated in  FIG. 14 ; and 
         FIG. 16A  is a multi-screen display device of the related art. 
         FIG. 16B  is a multi-screen display device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     Advantages and features of the present disclosure, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Furthermore, the present disclosure is only defined by scopes of claims. 
     A shape, a size, a ratio, an angle, and a number disclosed in the drawings for describing embodiments of the present disclosure are merely an example, and thus, the present disclosure is not limited to the illustrated details. Like reference numerals refer to like elements throughout. In the following description, when the detailed description of the relevant known technology is determined to unnecessarily obscure the important point of the present disclosure, the detailed description will be omitted. 
     In a case where ‘comprise’, ‘have’, and ‘include’ described in the present specification are used, another part may be added unless ‘only˜’ is used. The terms of a singular form may include plural forms unless referred to the contrary. 
     In construing an element, the element is construed as including an error range although there is no explicit description. 
     In describing a position relationship, for example, when a position relation between two parts is described as ‘on˜’, ‘over˜’, ‘under˜’ and ‘next˜’, one or more other parts may be disposed between the two parts unless ‘just’ or ‘direct’ is used. 
     In describing a time relationship, for example, when the temporal order is described as ‘after˜’, ‘subsequent˜’, ‘next˜’, and ‘before˜’, a case which is not continuous may be included unless ‘just’ or ‘direct’ is used. 
     It will be understood that, although the terms “first”, “second”, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. 
     A first horizontal axis direction, a second horizontal axis direction, and a vertical axis direction should not be construed as only a geometric relationship where a relationship therebetween is vertical, and may denote having a broader directionality within a scope where elements of the present disclosure operate functionally. 
     The term “at least one” should be understood as including any and all combinations of one or more of the associated listed items. For example, the meaning of “at least one of a first item, a second item, and a third item” denotes the combination of all items proposed from two or more of the first item, the second item, and the third item as well as the first item, the second item, or the third item. 
     Features of various embodiments of the present disclosure may be partially or overall coupled to or combined with each other, and may be variously inter-operated with each other and driven technically as those skilled in the art can sufficiently understand. The embodiments of the present disclosure may be carried out independently from each other, or may be carried out together in co-dependent relationship. 
     Hereinafter, exemplary embodiments of a light emitting diode display device and a multi-screen display device using the same according to the present disclosure will be described in detail with reference to the accompanying drawings. In the specification, in adding reference numerals for elements in each drawing, it should be noted that like reference numerals already used to denote like elements in other drawings are used for elements wherever possible. In the following description, when the detailed description of the relevant known function or configuration is determined to unnecessarily obscure the important point of the present disclosure, the detailed description will be omitted. 
       FIG. 1  is a plan view of a light emitting diode display device according to an embodiment of the present disclosure.  FIG. 2  is a plan view illustrating a rear surface of a substrate illustrated in  FIG. 1 .  FIG. 3  is a diagram for describing a configuration of a unit pixel according to an embodiment illustrated in  FIG. 1 . 
     Referring to  FIGS. 1 to 3 , the light emitting diode display device according to an embodiment of the present disclosure may include a substrate  100 , a plurality of first unit pixels UP 1 , and a plurality of second unit pixels UP 2 . 
     The substrate  100  may be a thin film transistor (TFT) array substrate and may be formed of glass, a plastic material, and/or the like. The substrate  100  according to an embodiment may include a first display area AA 1  and a second display area AA 2 . 
     The first display area AA 1  may be defined as a center area other than an edge of the substrate  100 . 
     The second display area AA 2  may be defined to surround the first display area AA 1  and may overlap the edge of the substrate  100 . 
     In addition, the substrate  100  may further include a non-display area IA surrounding the second display area AA 2 . The non-display area IA may be provided between an outer surface (e.g., a side surface) of the substrate  100  and the second display area AA 2 , may have a relatively very narrow width, and may be defined as a bezel area. 
     The plurality of first unit pixels UP 1  may be provided in the first display area AA 1 . In this case, the plurality of first unit pixels UP 1  may be arranged at a predetermined first reference pixel pitch along a first horizontal axis direction X and at a predetermined second reference pixel pitch along a second horizontal axis direction Y in the first display area AA 1 . Here, the first horizontal axis direction X may be parallel to a first lengthwise direction X of the substrate  100 , for example, a long side length direction of the substrate  100 , and the second horizontal axis direction Y may be parallel to a second lengthwise direction Y of the substrate  100 , for example, a short side length direction of the substrate  100 . The first reference pixel pitch may be defined as a distance between center portions of two first unit pixels UP 1  which are adjacent to each other along the first horizontal axis direction X, and the second reference pixel pitch may be defined as a distance between center portions of two first unit pixels UP 1  which are adjacent to each other along the second horizontal axis direction Y. 
     The plurality of second unit pixels UP 2  may be provided in the second display area AA 2 . In this case, the second unit pixels UP 2  may each have a size which is less than that of each of the first unit pixels UP 1 . That is, a distance between a center portion of each of the second unit pixels UP 2  and the outer surface of the substrate  100  may be set to half or less of each of the reference pixel pitches. 
     Adjacent first unit pixels UP 1  and second unit pixels UP 2  may be provided to have a reference pixel pitch. Therefore, in the light emitting diode display device according to the present embodiment, the plurality of first unit pixels UP 1  provided on the substrate  100  may have the same size and may be arranged at the same reference pixel pitch, and in this case, a size of each of a plurality of second unit pixels UP 2  adjacent to the outer surface of the substrate  100  is reduced, whereby the light emitting diode display device has a bezel width suitable for minimizing a boundary portion between display devices coupled to each other in a multi-screen display device. 
     The substrate  100  according to an embodiment may include a plurality of pixel driving lines and a plurality of subpixels SP 1  to SP 3 . 
     The pixel driving lines may be provided on a front surface  100   a  of the substrate  100  and may supply signals necessary for each of the plurality of subpixels SP 1  to SP 3 . The pixel driving lines according to an embodiment may include a plurality of gate lines GL, a plurality of data lines DL, a plurality of driving power lines DPL, and a plurality of common power lines CPL. 
     The plurality of gate lines GL may be provided on the front surface  100   a  of the substrate  100 , may long extend along the first horizontal axis direction X of the substrate  100 , may be arranged along the second horizontal axis direction Y, and may be spaced apart from each other by a certain interval. 
     The plurality of data lines DL may be provided on the front surface  100   a  of the substrate  100  to intersect the plurality of gate lines GL, may long extend along the second horizontal axis direction Y of the substrate  100 , may be arranged along the first horizontal axis direction X, and may be spaced apart from each other by a certain interval. 
     The plurality of driving power lines DPL may be provided on the substrate  100  in parallel with the plurality of data lines DL and may be formed along with the plurality of data lines DL. Each of the plurality of driving power lines DPL may supply a pixel driving power, supplied from the outside, to an adjacent subpixel SP. 
     The plurality of common power lines CPL may be arranged on the substrate  100  in parallel with the plurality of gate lines GL and may be formed along with the plurality of gate lines GL. Each of the plurality of common power lines CPL may supply a common power, supplied from the outside, to adjacent subpixels SP 1  to SP 3 . 
     The plurality of subpixels SP 1  to SP 3  may be respectively provided in a plurality of subpixel areas defined by intersections of the gate lines GL and the data lines DL. Each of the plurality of subpixels SP 1  to SP 3  may be defined as an area corresponding to a minimum unit where light is actually emitted. 
     At least three adjacent subpixels SP 1  to SP 3  may configure one unit pixel UP for displaying colors. For example, the one unit pixel UP may include a red subpixel SP 1 , a green subpixel SP 2 , and a blue subpixel SP 3  which are adjacent to each other along the first horizontal axis direction X, and may further include a white subpixel for enhancing luminance. 
     At least three subpixels SP 1  to SP 3  which are provided adjacent to each other in the first display area AA 1  may be defined as a first unit pixel UP 1 , and at least three subpixels SP 1  to SP 3  which are provided adjacent to each other in the second display area AA 2  may be defined as a second unit pixel UP 2 . 
     Optionally, one driving power line DPL may be provided in each of the plurality of first unit pixels UP 1 , and one driving power line DPL may be provided in each of the plurality of second unit pixels UP 2 . In this case, the at least three subpixels SP 1  to SP 3  configuring each of unit pixels UP 1  and UP 2  may share one driving power line DPL. Therefore, the number of driving power lines for driving each of the subpixels SP 1  to SP 3  is reduced, and in proportion to the reduced number of the driving power lines, an aperture rate of each of the unit pixels UP 1  and UP 2  increases or a size of each of the unit pixels UP 1  and UP 2  decreases. 
     The plurality of subpixels SP 1  to SP 3  according to an embodiment may each include a pixel circuit PC, a concave portion  130 , and a micro light emitting device  150 . 
     The pixel circuit PC may be provided in a circuit area defined in each subpixel SP and may be connected to a gate line GL, a data line DL, and a driving power line DPL which are adjacent to the pixel circuit PC. The pixel circuit PC may control a current flowing in the micro light emitting device  150  according to a data signal supplied through the data line DL in response to a scan pulse supplied through the gate line GL, based on the pixel driving power supplied through the driving power line DPL. The pixel circuit PC according to an embodiment may include a switching TFT T 1 , a driving TFT T 2 , and a capacitor Cst. 
     The switching TFT T 1  may include a gate electrode connected to the gate line GL, a first electrode connected to the data line DL, and a second electrode connected to a gate electrode N 1  of the driving TFT T 2 . Here, each of the first and second electrodes of the switching TFT T 1  may be a source electrode or a drain electrode according to a direction of a current. The switching TFT T 1  may be turned on according to the scan pulse supplied through the gate line GL and may supply the data signal, supplied through the data line DL, to the driving TFT T 2 . 
     The driving TFT T 2  may be turned on by a voltage supplied through the switching TFT T 1  and/or a voltage of the capacitor Cst to control the amount of current flowing from the driving power line DPL to the micro light emitting device  150 . To this end, the driving TFT T 2  according to an embodiment may include a gate electrode connected to the second electrode N 1  of the switching TFT T 1 , a drain electrode connected to the driving power line DPL, and a source electrode connected to the micro light emitting device  150 . The driving TFT T 2  may control a data current flowing from the driving power line DPL to the micro light emitting device  150  according to the data signal supplied through the switching TFT T 1 , thereby allowing the micro light emitting device  150  to emit light having brightness proportional to the data signal. 
     The capacitor Cst may be provided in an overlap area between the gate electrode N 1  and the source electrode of the driving TFT T 2 , may store a voltage corresponding to the data signal supplied to the gate electrode of the driving TFT T 2 , and may turn on the driving TFT T 2  with the stored voltage. 
     Optionally, the pixel circuit PC may further include at least one compensation TFT for compensating for a threshold voltage shift of the driving TFT T 2 , and moreover, may further include at least one auxiliary capacitor. The pixel circuit PC may be additionally supplied with a compensation power such as an initialization voltage, based on the number of TFTs and auxiliary capacitors. Therefore, the pixel circuit PC according to the present embodiment may drive the micro light emitting device  150  through a current driving manner identically to each subpixel of an organic light emitting display device, and thus, may be replaced with a pixel circuit of organic light emitting display devices known to those skilled in the art. 
     The concave portion  130  may be provided in each of the plurality of subpixels SP 1  to SP 3  and may be concavely provided for accommodating the micro light emitting device  150 . In a process of mounting the micro light emitting device  150  on each of the plurality of subpixels SP 1  to SP 3 , the concave portion  130  prevents deviation of the micro light emitting device  150  and enhances an alignment precision of the micro light emitting device  150 . 
     The micro light emitting device  150  may be mounted on the concave portion  130  provided in each of the plurality of subpixels SP 1  to SP 3 . The micro light emitting device  150  may be electrically connected to the pixel circuit PC of a corresponding subpixel SP and a corresponding common power line CPL, and thus, may emit light with a current flowing from the pixel circuit PC (i.e., the driving TFT T 2 ) to the common power line CPL. The micro light emitting device  150  according to an embodiment may be a micro light emitting device or a micro light emitting diode chip which emits one of red light, green light, blue light, and white light. For example, the micro light emitting device  150  may be a micro light emitting device or a micro light emitting diode chip. Here, the micro light emitting diode chip may have a scale of 1 μm to 100 μm, but is not limited thereto. In other embodiments, the micro light emitting diode chip may have a size which is less than that of an emissive area other than a circuit area occupied by the pixel circuit PC in a corresponding subpixel area. 
     The light emitting diode display device according to the present embodiment may further include a display driving circuit. 
     The display driving circuit may be disposed on a rear surface of the substrate  100  and may allow the micro light emitting device  150  of each subpixel SP to emit light. The display driving circuit according to an embodiment may include a plurality of first pad parts PP 1 , a plurality of first routing lines RL 1 , a plurality of second pad parts PP 2 , a plurality of second routing lines RL 2 , a data driving circuit  210 , a gate driving circuit  230 , a control board  250 , and a timing controller  270 . 
     The plurality of first pad parts PP 1  may be arranged at certain intervals on a first side rear edge of the substrate  100 . The plurality of first pad parts PP 1  may each include a plurality of first pads. 
     The plurality of first routing lines RL 1  may be electrically connected to respective ends of a plurality of pixel driving lines (in more detail, the plurality of data lines DL) provided on the front surface  100   a  of the substrate  100 , and moreover, may be provided on in a first non-display area IA and a first outer surface of the substrate  100  and a rear edge of the substrate  100  and may be electrically connected to the plurality of first pad parts PP 1 . That is, the plurality of first routing lines RL 1  may be provided to surround the first outer surface of the substrate  100 , one ends of the first routing lines RL 1  may be respectively connected to the plurality of data lines DL in the first non-display area IA in a one-to-one relationship, and the other ends of the first routing lines RL 1  may be respectively connected to the first pads of a corresponding first pad part PP 1  provided on a rear surface  100   b  of the substrate  100 . Here, the first non-display area IA of the substrate  100  may be a lower edge area of the substrate  100  illustrated in  FIG. 1 . 
     The plurality of second pad parts PP 2  may be arranged at certain intervals on a second side rear edge of the substrate  100 . The plurality of second pad parts PP 2  may each include a plurality of second pads. 
     The plurality of second routing lines RL 2  may be electrically connected to respective ends of a plurality of pixel driving lines (in more detail, the plurality of gate lines GL) provided on the front surface  100   a  of the substrate  100 , and moreover, may be provided on in a second non-display area IA and a second outer surface of the substrate  100  and the rear edge of the substrate  100  and may be electrically connected to the plurality of second pad parts PP 2 . That is, the plurality of second routing lines RL 2  may be provided to surround the second outer surface of the substrate  100 , one ends of the second routing lines RL 2  may be respectively connected to the plurality of gate lines GL in the second non-display area IA in a one-to-one relationship, and the other ends of the second routing lines RL 2  may be respectively connected to the second pads of a corresponding second pad part PP 2  provided on the rear surface  100   b  of the substrate  100 . Here, the second non-display area IA of the substrate  100  may be a right edge area of the substrate  100  illustrated in  FIG. 1 . 
     The data driving circuit  210  may include a plurality of data flexible circuit films  211  and a plurality of data driving integrated circuits (ICs)  213 . 
     The plurality of data flexible circuit films  211  may be respectively attached on, through a film attachment process, the plurality of first pad parts PP 1  provided on the rear surface  100   b  of the substrate  100  in a one-to-one relationship. 
     Each of the plurality of data driving ICs  213  may be individually mounted on a corresponding data flexible circuit film of the plurality of data flexible circuit films  211 . The data driving ICs  213  may receive subpixel data and a data control signal supplied from the timing controller  270 , convert the subpixel data into analog data voltages by subpixels according to the data control signal, and respectively supply the analog data voltages to the data lines DL. 
     Optionally, the plurality of data driving ICs  213  may be directly mounted on the rear surface  100   b  of the substrate  100  so as to be respectively connected to the plurality of first pad parts PP 1  in a one-to-one relationship without being mounted on the data flexible circuit films  211 . Here, the plurality of data driving ICs  213  may be mounted on the rear surface  100   b  of the substrate  100  through a chip mounting process based on a chip-on glass (COG) type. In this case, the data flexible circuit films  211  may be removed, and thus, a configuration of the data driving circuit  210  is simplified. 
     The gate driving circuit  230  may include a plurality of gate flexible circuit films  231  and a plurality of gate driving ICs  233 . 
     The plurality of gate flexible circuit films  231  may be respectively attached on, through a film attachment process, the plurality of second pad parts PP 2  provided on the rear surface  100   b  of the substrate  100  in a one-to-one relationship. 
     Each of the plurality of gate driving ICs  233  may be individually mounted on a corresponding gate flexible circuit film of the plurality of gate flexible circuit films  231 . Each of the gate driving ICs  233  may generate a scan pulse, based on a gate control signal supplied from the timing controller  270  and may supply the generated scan pulse to a corresponding gate line GL corresponding to a predetermined order. 
     Optionally, the plurality of gate driving ICs  233  may be directly mounted on the rear surface  100   b  of the substrate  100  so as to be respectively connected to the plurality of second pad parts PP 2  in a one-to-one relationship without being mounted on the gate flexible circuit films  231 . Here, the plurality of gate driving ICs  233  may be mounted on the rear surface  100   b  of the substrate  100  through a chip mounting process based on a COG type. In this case, the gate flexible circuit films  231  may be removed, and thus, a configuration of the gate driving circuit  230  is simplified. 
     The control board  250  may be connected to the plurality of data flexible circuit films  211  and the plurality of gate flexible circuit films  231 . For example, the control board  250  may be electrically connected to the plurality of data flexible circuit films  211  through a plurality of first signal transmission cables STC 1  and may be electrically connected to the plurality of gate flexible circuit films  231  through a plurality of second signal transmission cables STC 2 . The control board  250  may support the timing controller  270  and may transfer signals and power between the elements of the display driving circuit. 
     The timing controller  270  may be mounted on the control board  250  and may receive image data and a timing synchronization signal supplied from a display driving system through a user connector provided on the control board  250 . The timing controller  270  may align the image data according to a subpixel arrangement structure of the first and second display areas AA 1  and AA 2  based on the timing synchronization signal to generate subpixel data and may supply the generated subpixel data to the data driving ICs  213 . Also, the timing controller  270  may generate the data control signal and the gate control signal, based on the timing synchronization signal and may control a driving timing of each of the data driving ICs  213  and the gate driving ICs  233 . 
     Optionally, the plurality of data driving ICs  213 , the plurality of gate driving ICs  233 , and the timing controller  270  may be integrated into one integration driving IC. In this case, the one integration driving IC may be mounted on the rear surface  100   b  of the substrate  100 , and each of the plurality of first routing lines RL 1  and the plurality of second routing lines RL 2  may be additionally routed on the rear surface  100   b  of the substrate  100  and may be electrically connected to a corresponding channel provided in the integration driving IC. In this case, the plurality of first pad parts PP 1 , the plurality of second pad parts PP 2 , the plurality of data flexible circuit films  211 , and the plurality of gate flexible circuit films  231  may be omitted. 
     In addition, in the present embodiment, corners of the substrate  100  may be chamfered to have a certain angle or length, or may be rounded to have a certain curvature. Therefore, in the present embodiment, the plurality of first routing lines RL 1  and the plurality of second routing lines RL 2  may be easily formed in the corners and outer surface of the substrate  100  without disconnection. 
     In the light emitting diode display device according to the present embodiment, a size of the second unit pixel UP 2  provided in the second display area AA 2  overlapping the edge of the substrate  100  may be set less than that of the first unit pixel UP 1  provided in the first display area AA 1  of the substrate  100 , and thus, the light emitting diode display device has a bezel width suitable for minimizing a boundary portion between display devices coupled to each other in a multi-screen display device. That is, in the light emitting diode display device according to the present embodiment, a size of each of the plurality of second unit pixels UP 2  adjacent to the outer surface of the substrate  100  is reduced, and the display driving circuit may be provided on the rear surface of the substrate  100 , thereby minimizing a bezel area of the substrate  100 . Also, since the micro light emitting device  150  is accommodated into the concave portion  130  provided in each of the subpixels SP 1  to SP 3 , alignment precision is enhanced in the mounting (or transfer) process for the micro light emitting device  150 , and thus, productivity is enhanced. 
       FIG. 4  is a cross-sectional view for describing a structure of one subpixel illustrated in  FIG. 3 , and  FIG. 5  is a cross-sectional view for describing a structure of a micro light emitting device illustrated in  FIG. 4 . 
     Referring to  FIGS. 4 and 5  along with  FIG. 3 , a plurality of subpixels SP 1  to SP 3  of a light emitting diode display device according to the present embodiment may each include a pixel circuit PC, a passivation layer  110 , a concave portion  130 , a micro light emitting device  150 , a planarization layer  160 , a pixel electrode PE, and a common electrode CE. 
     First, in  FIG. 4 , a thickness of a substrate  100  is relatively thinly illustrated, but the substrate  100  may substantially have a thickness which is relatively much thicker than a total thickness of a layered structure provided on the substrate  100 . 
     The pixel circuit PC may include a switching TFT T 1 , a driving TFT T 2 , and a capacitor Cst. The pixel circuit PC is as described above, and thus, its detailed description is not provided. Hereinafter, a structure of the driving TFT T 2  will be described for example. 
     The driving TFT T 2  may include a gate electrode GE, a semiconductor layer SCL, an ohmic contact layer OCL, a source electrode SE, and a drain electrode DE. 
     The gate electrode GE may be formed on the substrate  100  along with the gate line GL. The gate electrode GE may be covered by a gate insulation layer  103 . The gate insulation layer  103  may be formed of a single layer or a multilayer including an inorganic material and may be formed of silicon oxide (SiOx) silicon nitride (SiNx), and/or the like. 
     The semiconductor layer SCL may be provided in a predetermined pattern (or island) type on the gate insulation layer  103  to overlap the gate electrode GE. The semiconductor layer SCL may be formed of a semiconductor material including one of amorphous silicon, polycrystalline silicon, oxide, and an organic material, but is not limited thereto. 
     The ohmic contact layer OCL may be provided in a predetermined pattern (or island) type on the semiconductor layer SCL. Here, the ohmic contact layer OCL is for an ohmic contact between the semiconductor layer SCL and the source and drain electrodes SE and DE and may be omitted. 
     The source electrode SE may be formed on one side of the ohmic contact layer OCL to overlap one side of the semiconductor layer SCL. The source electrode SE may be formed along with the data lines DL and the driving power lines DPL. 
     The drain electrode DE may be formed on the other side of the ohmic contact layer OCL to overlap the other side of the semiconductor layer SCL and may be spaced apart from the source electrode SE. The drain electrode DE may be formed along with the source electrode SE and may branch or protrude from an adjacent driving power line DPL. 
     In addition, the switching TFT T 1  configuring the pixel circuit PC may be formed in a structure which is the same as that of the driving TFT T 2 . In this case, the gate electrode of the switching TFT T 1  may branch or protrude from the gate line GL, the first electrode of the switching TFT T 1  may branch or protrude from the data line DL, and the second electrode of the switching TFT T 1  may be connected to the gate electrode GE of the driving TFT T 2  through a via hole provided in the gate insulation layer  103 . 
     The pixel circuit PC may be covered by an interlayer insulation layer  105 . The interlayer insulation layer  105  may be provided all over the substrate  100  to cover the pixel circuit PC including the driving TFT T 2 . The interlayer insulation layer  105  according to an embodiment may be formed of an inorganic material, such as SiOx or SiNx, or an organic material such as benzocyclobutene or photo acryl. The interlayer insulation layer  105  may not be provided. 
     The passivation layer  110  may be provided all over the substrate  100  to cover the subpixel SP (i.e., the pixel circuit PC), or may be provided all over the substrate  100  to cover the interlayer insulation layer  105 . The passivation layer  110  may protect the pixel circuit PC including the driving TFT T 2  and may provide a planar surface on the interlayer insulation layer  105 . The passivation layer  110  according to an embodiment may be formed of an organic material such as benzocyclobutene or photo acryl, and particularly, may be formed of photo acryl for convenience of a process. 
     The concave portion  130  may be provided in an emissive area of a subpixel area defined in the subpixel SP and may accommodate the micro light emitting device  150 . The concave portion  130  according to an embodiment may be provided concavely from the passivation layer  110  to have a certain depth D 1 . In this case, the concave portion  130  may include an accommodating space which is provided concavely from a top  110   a  of the passivation layer  110  to have a depth D 1  corresponding to a thickness (or a total height) of the micro light emitting device  150 . Here, a floor surface of the concave portion  130  may be formed by removing a portion of the passivation layer  110 , a whole portion of the passivation layer  110 , the whole portion of the passivation layer  110  and a portion of the interlayer insulation layer  105 , or a whole portion of each of the passivation layer  110 , the interlayer insulation layer  105 , and the gate insulation layer  103  in order to have the depth D 1  which is set based on the thickness of the micro light emitting device  150 . For example, the concave portion  130  may be provided to have a depth of 2 μm to 6 μm from the top  110   a  of the passivation layer  110 . The concave portion  130  may have a groove or cup shape having a size which is wider than a rear surface (or a bottom) of the micro light emitting device  150 . 
     The concave portion  130  according to an embodiment may include an inclined surface provided between the floor surface and the top  110   a  of the passivation layer  110 , and the inclined surface may allow light emitted from the micro light emitting device  150  to travel toward the front of concave portion  130 . 
     The micro light emitting device  150  may be mounted on the concave portion  130  and may be electrically connected to the pixel circuit PC and a common power line CPL, and thus, may emit light with a current flowing from the pixel circuit PC (i.e., the driving TFT T 2 ) to the common power line CPL. The micro light emitting device  150  according to an embodiment may include a light emitting layer EL, a first electrode (or an anode terminal) E 1 , and a second electrode (or a cathode terminal) E 2 . 
     The light emitting layer EL may emit light according to a recombination of an electron and a hole based on a current flowing between the first electrode E 1  and the second electrode E 2 . The light emitting layer EL according to an embodiment may include a first semiconductor layer  151 , an active layer  153 , and a second semiconductor layer  155 . 
     The first semiconductor layer  151  may supply an electron to the active layer  153 . The first semiconductor layer  151  according to an embodiment may be formed of an n-GaN-based semiconductor material, and examples of the n-GaN-based semiconductor material may include GaN, AlGaN, InGaN, AlInGaN, etc. Here, silicon (Si), germanium (Ge), selenium (Se), tellurium (Te), or carbon (C) may be used as impurities used for doping of the first semiconductor layer  151 . 
     The active layer  153  may be provided on one side of the first semiconductor layer  151 . The active layer  153  may have a multi quantum well (MQW) structure which includes a well layer and a barrier layer which is higher in band gap than the well layer. The active layer  153  according to an embodiment may have an MQW structure of InGaN/GaN or the like. 
     The second semiconductor layer  155  may be provided on the active layer  153  and may supply a hole to the active layer  153 . The second semiconductor layer  155  according to an embodiment may be formed of a p-GaN-based semiconductor material, and examples of the p-GaN-based semiconductor material may include GaN, AlGaN, InGaN, AlInGaN, etc. Here, magnesium (Mg), zinc (Zn), or beryllium (Be) may be used as impurities used for doping of the second semiconductor layer  155 . 
     The first electrode E 1  may be provided on the second semiconductor layer  155 . The first electrode E 1  may be connected to the source electrode SE of the driving TFT T 2 . 
     The second electrode E 2  may be provided on the other side of the first semiconductor layer  151  and may be electrically disconnected from the active layer  153  and the second semiconductor layer  155 . The second electrode E 2  may be connected to the common power line CPL. 
     Each of the first and second electrodes E 1  and E 2  according to an embodiment may be formed of a material including one or more materials of a metal material, such as gold (Au), tungsten (W), platinum (Pt), silicon (Si), iridium (Ir), silver (Ag), copper (Cu), nickel (Ni), titanium (Ti), or chromium (Cr), and an alloy thereof. In other embodiments, each of the first and second electrodes E 1  and E 2  may be formed of a transparent conductive material, and examples of the transparent conductive material may include indium tin oxide (ITO), indium zinc oxide (IZO), etc. However, the present embodiment is not limited thereto. 
     In addition, the first semiconductor layer  151 , the active layer  153 , and the second semiconductor layer  155  may be provided in a structure of being sequentially stacked on a semiconductor substrate. Here, the semiconductor substrate may include a semiconductor material included in a sapphire substrate or a silicon substrate. The semiconductor substrate may be used as a growth semiconductor substrate for growing each of the first semiconductor layer  151 , the active layer  153 , and the second semiconductor layer  155 , and then, may be separated from the first semiconductor layer  151  through a substrate separation process. Here, the substrate separation process may be a laser lift-off process or a chemical lift-off process. Therefore, since the growth semiconductor substrate is removed from the micro light emitting device  150 , the micro light emitting device  150  has a thin thickness, and thus, may be accommodated into the concave portion  130  provided in each subpixel SP. 
     The micro light emitting device  150  may emit the light according to the recombination of the electron and the hole based on the current flowing between the first electrode E 1  and the second electrode E 2 . In this case, the light emitted from the micro light emitting device  150  may pass through the first and second electrodes E 1  and E 2  and may be output to the outside. In other words, the light emitted from the micro light emitting device  150  may pass through the first and second electrodes E 1  and E 2  and may be output in a second direction opposite to a first direction toward the floor surface of the concave portion  130 , thereby displaying an image. 
     The micro light emitting device  150  may include a first portion (or a front portion) FP, including the first and second electrodes E 1  and E 2  connected to the pixel circuit PC, and a second portion (or a rear portion) RP opposite to the first portion FP. In this case, the first portion FP may be disposed relatively farther away from the floor surface of the concave portion  130  than the second portion RP. Here, the first portion FP may have a size which is less than that of the second portion RP, and in this case, the micro light emitting device  150  may have a cross-sectional surface having a trapezoid shape which includes a top corresponding to the first portion FP and a bottom corresponding to the second portion RP. 
     The planarization layer  160  may be provided on the passivation layer  110  to cover the micro light emitting device  150 . That is, the planarization layer  160  may be provided on the passivation layer  110  to have a thickness which enables the planarization layer  160  to cover a top of the passivation layer  110  and a front surface of the other accommodating space of the concave portion  130  into which the micro light emitting device  150  is accommodated. 
     The planarization layer  160  may provide a planarization surface on the passivation layer  110 . Also, the planarization layer  160  may be buried into the other accommodating space of the concave portion  130  into which the micro light emitting device  150  is accommodated, thereby fixing a position of the micro light emitting device  150 . 
     The pixel electrode PE may electrically connect the first electrode E 1  of the micro light emitting device  150  to the source electrode SE of the driving TFT T 2  and may be defined as an anode electrode. The pixel electrode PE according to an embodiment may be provided on a top  160   a  of the planarization layer  160  overlapping the driving TFT T 2  and the first electrode E 1  of the micro light emitting device  150 . The pixel electrode PE may be electrically connected to the source electrode SE of the driving TFT T 2  through a first circuit contact hole CCH 1  which is provided to pass through the interlayer insulation layer  105 , the passivation layer  110 , and the planarization layer  160 , and may be electrically connected to the first electrode E 1  of the micro light emitting device  150  through a first electrode contact hole ECH 1  provided in the planarization layer  160 . Therefore, the first electrode E 1  of the micro light emitting device  150  may be electrically connected to the source electrode SE of the driving TFT T 2  through the pixel electrode PE. If the light emitting diode display device has a top emission structure, the pixel electrode PE may be formed of a transparent conductive material, and if the light emitting diode display device has a bottom emission structure, the pixel electrode PE may be formed of a light reflection conductive material. Here, the transparent conductive material may be indium tin oxide (ITO), indium zinc oxide (IZO), or the like, but is not limited thereto. The light reflection conductive material may be Al, Ag, Au, Pt, Cu, or the like, but is not limited thereto. The pixel electrode PE including the light reflection conductive material may be formed of a single layer including the light reflection conductive material or a multilayer including a plurality of the single layers which are stacked. 
     The common electrode CE may be electrically connected to the second electrode E 2  of the micro light emitting device  150  and the common power line CPL and may be defined as a cathode electrode. The common electrode CE may be provided on the top  160   a  of the planarization layer  160  overlapping the second electrode E 2  of the micro light emitting device  150  and the common power line CPL. Here, the common electrode CE may be formed of a material which is the same as that of the pixel electrode PE. 
     One side of the common electrode CE according to an embodiment may be electrically connected to the common power line CPL through a second circuit contact hole CCH 2  which is provided to pass through the gate insulation layer  103 , the interlayer insulation layer  105 , the passivation layer  110 , and the planarization layer  160 . The other side of the common electrode CE may be electrically connected to the second electrode E 2  of the micro light emitting device  150  through a second electrode contact hole ECH 2  which is provided in the planarization layer  160  to overlap the second electrode E 2  of the micro light emitting device  150 . Therefore, the second electrode E 2  of the micro light emitting device  150  may be electrically connected to the common power line CPL through the common electrode CE. 
     The pixel electrode PE and the common electrode CE according to an embodiment may be simultaneously provided through an electrode patterning process using a lithography process, an etching process, and a deposition process of depositing an electrode material on the planarization layer  160  including the first and second circuit contact holes CCH 1  and CCH 2  and the first and second electrode contact holes ECH 1  and ECH 2 . Therefore, in the present embodiment, since the common electrode CE and the pixel electrode PE connecting the micro light emitting device  150  and the pixel circuit PC are simultaneously formed, an electrode connection process is simplified, and a process time taken in a process of connecting the micro light emitting device  150  and the pixel circuit PC is considerably shortened, thereby enhancing a productivity of the light emitting diode display device. 
     The light emitting diode display device according to the present embodiment may further include a transparent buffer layer  170 . 
     The transparent buffer layer  170  may be provided on the substrate  100  to cover a whole portion of the planarization layer  160  where the pixel electrode PE and the common electrode CE are provided, and thus, may provide a planarization surface on the planarization layer  160 , thereby protecting the micro light emitting device  150  and the pixel circuit PC from an external impact. Therefore, the pixel electrode PE and the common electrode CE may be provided between the planarization layer  160  and the transparent buffer layer  170 . The transparent buffer layer  170  may be an optical clear adhesive (OCA) or an optical clear resin (OCR), but is not limited thereto. 
     The light emitting diode display device according to the present embodiment may further include a reflective layer  101  provided under an emissive area of each subpixel SP. 
     The reflective layer  101  may be provided between the floor surface of the concave portion  130  and the substrate  100  to overlap the emissive area including the micro light emitting device  150 . The reflective layer  101  according to an embodiment may be formed of a material which is the same as that of the gate electrode GE of the driving TFT T 2 , and may be provided on the same layer as the gate electrode GE. The reflective layer  101  may reflect light, which is incident from the micro light emitting device  150 , toward the first portion FP of the micro light emitting device  150 . Accordingly, the light emitting diode display device according to the present embodiment may include the reflective layer  101 , and thus, may have a top emission structure. However, if the light emitting diode display device according to the present embodiment has a bottom emission structure, the reflective layer  101  may be omitted. 
     Optionally, the reflective layer  101  may be formed of a material which is the same as that of the source/drain electrode SE/DE of the driving TFT T 2 , and may be provided on the same layer as the source/drain electrode SE/DE. 
     In the light emitting diode display device according to the present embodiment, the micro light emitting device  150  mounted in each subpixel SP may be adhered to the floor surface of the concave portion  130  by an adhesive member  120 . 
     The adhesive member  120  may be disposed between the concave portion  130  of each subpixel SP and the micro light emitting device  150  and may attach the micro light emitting device  150  on the floor surface of the concave portion  130 , thereby primarily fixing the micro light emitting display device  150 . 
     The adhesive member  120  according to an embodiment may be attached (coated) on the second portion RP of the micro light emitting device  150  (i.e., a back surface of the first semiconductor layer  151 ), and thus, in a mounting process of mounting the micro light emitting device  150  onto the concave portion  130 , the adhesive member  120  may be adhered to the concave portion  130  of each subpixel SP. 
     In other embodiments, the adhesive member  120  may be dotted onto the concave portion  130  of each subpixel SP and may be spread by pressure which is applied to the adhesive member  120  in a mounting process performed for the micro light emitting device  150 , and thus, may be adhered to the second portion RP of the micro light emitting device  150 . Therefore, the micro light emitting device  150  mounted on the concave portion  130  may be primarily position-fixed by the adhesive member  120 . Accordingly, according to the present embodiment, the mounting process for the micro light emitting device  150  may be performed in a method of simply attaching the micro light emitting device  150  on the floor surface of the concave portion  130 , and thus, a mounting process time taken in performing the mounting process for the micro light emitting device  150  is shortened. 
     In other embodiments, the adhesive member  120  may be coated on the top  110   a  of the passivation layer  110  and the floor surface and an inclined surface of the concave portion  130 . That is, the adhesive member  120  may be provided to wholly cover a portion of a front surface of the passivation layer  110  except the contact holes. In other words, the adhesive member  120  may be disposed between the passivation layer  110  and the planarization layer  160  and may be disposed between the passivation layer  110  and the micro light emitting device  150 . In other embodiments, the adhesive member  120  may be coated on the whole top  110   a  of the passivation layer  110 , where the concave portion  130  is provided, to a certain thickness. A portion of the adhesive member  120  coated on the top  110   a  of the passivation layer  110 , where the contact holes are to be provided, may be removed when forming the contact holes. Therefore, in the present embodiment, immediately before a mounting process for the micro light emitting device  150 , the adhesive member  120  may be coated on the whole top  110   a  of the passivation layer  110  to have a certain thickness, and thus, according to the present embodiment, a process time taken in forming the adhesive member  120  is shortened. 
     In the present embodiment, the adhesive member  120  may be provided on the whole top  110   a  of the passivation layer  110 , and thus, the planarization layer  160  according to the present embodiment is provided to cover the adhesive member  120 . 
     A mounting process for a micro light emitting device according to an embodiment may include a process of mounting a red micro light emitting device on each of red subpixels SP 1 , a process of mounting a green micro light emitting device on each of green subpixels SP 2 , and a process of mounting a blue micro light emitting device on each of blue subpixels SP 3 , and moreover, may further include a process of mounting a white micro light emitting device on each of white subpixels. 
     The mounting process for the micro light emitting device according to an embodiment may include only a process of mounting the white micro light emitting device on each of subpixels. In this case, the substrate  100  may include a color filter layer overlapping each subpixel. The color filter layer may transmit only light, having a wavelength of a color corresponding to a corresponding subpixel, of white light. 
     The mounting process for the micro light emitting device according to an embodiment may include only a process of mounting a first-color micro light emitting device on each subpixel. In this case, the substrate  100  may include a wavelength conversion layer and the color filter layer overlapping each subpixel. The wavelength conversion layer may emit light of a second color, based on some of light of the first color incident from the first-color micro light emitting device. The color filter layer may transmit only light, having a wavelength of a color corresponding to a corresponding subpixel, of white light based on a combination of the light of the first color and the light of the second color. Here, the first color may be blue, and the second color may be yellow. The wavelength conversion layer may include a phosphor or a quantum dot which emits the light of the second color, based on some of the light of the first color. 
       FIG. 6  is a plan view for describing a concave portion provided in a unit pixel according to an embodiment of the present disclosure, and  FIG. 7  is a cross-sectional view taken along line I-I′ illustrated in  FIG. 6 . 
     Referring to  FIGS. 6 and 7 , in the present embodiment, first to third subpixels SP 1  to SP 3  configuring each of a plurality of first unit pixels UP 1  may each include a concave portion  130  which is provided concavely from a top of a passivation layer  110 . 
     First, in each of the first unit pixels UP 1 , the second subpixel SP 2  may be provided in the middle of a unit pixel area, the first subpixel SP 1  may be provided on one side of the second subpixel SP 2 , and the third subpixel SP 3  may be provided on the other side of the second subpixel SP 2 . 
     The concave portion  130  provided in the second subpixel SP 2  may have a planarly tetragonal shape, and a center line CLg 2  of the concave portion  130  with respect to a first horizontal axis direction X may match a second center line CL 2  of the second subpixel SP 2 . For example, the concave portion  130  of the second subpixel SP 2  may be provided in a center portion of the first unit pixel UP 1 . Therefore, a distance L between a center portion of the concave portion  130  provided in the second subpixel SP 2  and an outer surface of a substrate  100  may be set to half “P/2” or less of a reference pixel pitch P. 
     The concave portion  130  provided in the first subpixel SP 1  may have a planarly tetragonal shape and may be provided close to the concave portion  130  provided in the second subpixel SP 2 . That is, a center line CLg 1  of the concave portion  130  provided in the first subpixel SP 1  with respect to the first horizontal axis direction X may be provided at a position which is spaced apart from a center line CL 1  of the first subpixel SP 1  by a first distance d 1  in a direction toward the second subpixel SP 2 . 
     The concave portion  130  provided in the third subpixel SP 3  may have a planarly tetragonal shape and may be provided close to the concave portion  130  provided in the second subpixel SP 2 . That is, a center line CLg 3  of the concave portion  130  provided in the third subpixel SP 3  with respect to the first horizontal axis direction X may be provided at a position which is spaced apart from a center line CL 3  of the third subpixel SP 3  by a second distance d 2  in a direction toward the second subpixel SP 2 . 
     The first to third subpixels SP 1  to SP 3  of each of the first unit pixels UP 1  may have the same width Wa with respect to the first horizontal axis direction X. 
     In each of the first unit pixels UP 1 , the concave portions  130  respectively provided in the first to third subpixels SP 1  to SP 3  may be provided to concentrate on a center portion of the first unit pixel UP 1 . Each first unit pixel UP 1  may have a first width W 1  corresponding to a predetermined resolution, and the plurality of first unit pixels UP 1  may be arranged at the reference pixel pitch P. Here, the reference pixel pitch P may be defined as a distance between center portions of two first unit pixels UP 1  which are adjacent to each other with respect to the first horizontal axis direction X and a second horizontal axis direction Y. In other words, the reference pixel pitch P may be defined as a distance between the same subpixels provided in two first unit pixels UP 1  which are adjacent to each other with respect to the first horizontal axis direction X. That is, the reference pixel pitch P may be defined as a distance between micro light emitting devices  150  respectively provided in second subpixels SP 2  of two adjacent first unit pixels UP 1 . For example, the first unit pixel UP 1  may be configured with a red subpixel SP 1 , a green subpixel SP 2 , and a blue subpixel SP 3 , and in this case, the reference pixel pitch P may be a distance between concave portions  130  (or micro light emitting devices  150 ) respectively provided in adjacent red subpixels SP 1 , a distance between concave portions  130  (or micro light emitting devices  150 ) respectively provided in adjacent green subpixels SP 2 , or a distance between concave portions  130  (or micro light emitting devices  150 ) respectively provided in adjacent blue subpixels SP 3 , with respect to the first horizontal axis direction X. 
     In each of the plurality of second unit pixels UP 2 , the second subpixel SP 2  may be provided in the middle of a unit pixel area, the first subpixel SP 1  may be provided on one side of the second subpixel SP 2 , and the third subpixel SP 3  may be provided on the other side of the second subpixel SP 2  and may be provided adjacent to the outer surface of the substrate  100 . Here, the outer surface of the substrate  100  may be defined as a side wall vertical to an end of a front surface  100   a  of the substrate  100 , or may be defined as an outermost surface of the substrate  100  exposed to the outside. That is, the side wall of the substrate  100  may be directly exposed to the outside, or may be covered by structures such as a routing line, a passivation layer, etc., and thus may not be directly exposed to the outside. Therefore, the outer surface of the substrate  100  may be defined as the outermost surface of the substrate  100  exposed to the outside. 
     The concave portions  130  respectively provided in the first to third subpixels SP 1  to SP 3  in each second unit pixel UP 2  are the same as the concave portions of the first unit pixels UP 1 , and thus, their repetitive descriptions are not provided. 
     In each of the second unit pixels UP 2 , since each of the first and second subpixels SP 1  and SP 2  is adjacent to a corresponding first unit pixel UP 1 , each of the first and second subpixels SP 1  and SP 2  may be provided to have the width Wa which is the same as that of each of subpixels of the corresponding first unit pixel UP 1 . 
     On the other hand, the third subpixel SP 3  of each second unit pixel UP 2  may be provided to have a width Wb which is narrower than the width Wa of each of the first and second subpixels SP 1  and SP 2 . In detail, in each second unit pixel UP 2 , the concave portions  130  may be provided to concentrate on center portions of unit pixels, and thus, even when a portion of an area of the third subpixel SP 3  adjacent to the non-display area IA of the substrate  100  is removed, the quality of an image displayed on a corresponding unit pixel UP 2  is not affected. Therefore, the width Wb of the third subpixel SP 3  with respect to the first horizontal axis direction X may be reduced by the second distance d 2  at which the micro light emitting device  150  mounted on the third subpixel SP 3  is disposed close to the second subpixel SP 2  with respect to the center line CL 3  of the third subpixel SP 3 . In this case, a maximum distance L between the second unit pixel UP 2  and the outer surface of the substrate  100  may be set to half “P/2” or less of the reference pixel pitch P at which the plurality of first unit pixels UP 1  are arranged, namely, may be set equal to or less than half of the reference pixel pitch P. Therefore, since a size of each of the third subpixels SP 3  is reduced in the second unit pixels UP 2  adjacent to a bezel area of the substrate  100 , the light emitting diode display device according to the present embodiment has a bezel width suitable for a boundary portion between display devices connected to each other in a multi-screen display device. 
     In addition, the light emitting diode display device according to an embodiment of the present disclosure may further include a side sealing member  107 . 
     The side sealing member  107  may be provided to cover the outer surface of the substrate  100  and a side surface of the transparent buffer layer  170 . The side sealing member  107  according to an embodiment may be formed of a silicon-based or UV curing-based sealant (or resin), but considering a process tack time, the side sealing member  107  may be formed of a UV curing-based sealant. Also, the side sealing member  107  may have a color (for example, blue, red, green, or black), or may be formed of a colored resin or a light blocking resin for preventing side light leakage without being limited thereto. The side sealing member  107  prevents side light leakage while light emitted from the micro light emitting device  150  of each subpixel SP travels in a direction from the inside of the transparent buffer layer  170  to an outermost surface, and buffers an external impact to prevent a side surface of each of the substrate  100  and the transparent buffer layer  170  from being damaged by the external impact. 
       FIG. 8  is a diagram for describing an alternate embodiment of a concave portion according to an embodiment of the present disclosure. 
     Referring to  FIG. 8 , a plurality of concave portions  130  respectively provided in a plurality of subpixels SP 1 , SP 2  and SP 3  of each of a plurality unit pixels UP 1  and UP 2  according to the modification embodiment may have the same shapes and may be formed concavely from a passivation layer  110  to have different depths D 1 , D 2  and D 3  in respective subpixels SP, respectively. 
     The concave portions  130  according to an embodiment may be provided to have the different depths D 1  to D 3  from the passivation layer  110 , based on a height of a micro light emitting device  150  which is to be provided in a corresponding subpixel, thereby removing or minimizing a height deviation (or a step height) between micro light emitting devices by colors. 
     In order to realize a color image, the light emitting diode display device according to the present embodiment may include a red subpixel SP 1 , a green subpixel SP 2 , and a blue subpixel SP 3 , and the micro light emitting device  150  may be provided by colors and may be disposed in the concave portion  130  provided in a subpixel having a corresponding color. In this case, the color-based micro light emitting devices  150  may have different heights (or thicknesses) due to a process error of a manufacturing process. For example, thicknesses of the color-based micro light emitting devices  150  may be thickened in the order of red, green, and blue. In this case, the depths D 1  to D 3  of the concave portions  130  may be deeply provided in the order of the red subpixel SP 1 , the green subpixel SP 2 , and the blue subpixel SP 3 , based on a height of a corresponding micro light emitting device  150 . 
     Therefore, in the present embodiment, the depths of the concave portions  130  provided in respective subpixels may be differently set based on a height (or a thickness) of the micro light emitting device  150  which is to be provided in a corresponding subpixel, and thus, uppermost surfaces (for example, tops of first electrodes E 1 ) of the color-based micro light emitting devices  150  disposed in respective subpixels may be disposed on the same horizontal line HL, thereby preventing an open defect, where first electrodes (or second electrodes) of the color-based micro light emitting devices  150  are not exposed, from occurring due to a thickness deviation between the color-based micro light emitting devices  150  in a patterning process for first and second electrode contact holes. Also, in the present embodiment, in the top emission structure, an optical distance between a reflective layer  101  and the color-based micro light emitting devices of each subpixel is optimized by using the concave portions  130  which are provided to the different depths D 1  to D 3  in respective subpixels, and thus, a reflection efficiency of the reflective layer  101  is improved, thereby maximizing a light efficiency of each of the micro light emitting devices. 
       FIG. 9  is a plan view for describing an alternate embodiment of a concave portion according to an embodiment of the present disclosure. 
     Referring to  FIG. 9 , in the present embodiment, a plurality of concave portions  130  respectively provided in a plurality of subpixels SP 1  to SP 3  of each of a plurality of unit pixels UP 1  and UP 2  may communicate with each other without a boundary portion and may include one accommodating space. That is, each of a plurality of first unit pixels UP 1  and each of a plurality of second unit pixels UP 2  may include only one concave portion  130  provided all over first to third subpixels SP 1  to SP 3 . 
     The concave portion  130  may have a tetragonal shape which extends toward the first subpixel SP 1  and the third subpixel SP 3  with respect to a center portion of each of the unit pixels UP 1  and UP 2  or a center line CL 2  of the second subpixel SP 2 . That is, a center line CLg of the concave portion  130  may match the center line CL 2  of the second subpixels SP 2  with respect to the first horizontal axis direction X. 
     As described above, in the present embodiment, since the one concave portion  130  is provided in the unit pixels UP 1  and UP 2 , deviation of the micro light emitting device  150  is prevented in a mounting process for a micro light emitting device  150  corresponding to each of the subpixels SP 1  to SP 3 , and an alignment precision of the micro light emitting device  150  is enhanced. 
       FIG. 10  is a diagram for describing a routing line of the light emitting diode display device illustrated in  FIGS. 2 and 7 . 
     Referring to  FIG. 10 , in the light emitting diode display device according to the present embodiment, a substrate  100  may include a plurality of grooves  100   c  provided in a first non-display area IA 1 . 
     The first non-display area IA 1  of the substrate  100  may be defined as a lower non-display area of the substrate  100  overlapping an edge of each of a plurality of data lines DL. 
     The plurality of grooves  100   c  may be arranged at certain intervals along a first horizontal axis direction X and may be provided concavely in a direction from an outer surface of the substrate  100  to a second display area AA 2 . The plurality of grooves  100   c  according to an embodiment may be formed through a substrate cutting process. The substrate cutting process according to an embodiment may cut a portion of an edge of the substrate  100  corresponding to a space between the plurality of data lines DL by using a laser scribing process to form the plurality of grooves  100   c . Therefore, the outer surface of the substrate  100  may include the concavely provided plurality of grooves  100   c  and a plurality of protrusions  100   p  which are provided between the plurality of grooves  100   c  and respectively overlap ends of the plurality of data lines DL. 
     In the light emitting diode display device according to the present embodiment, a plurality of first routing lines RL 1  may be respectively connected to the plurality of data lines DL, provided on a front surface  100   a  of the substrate  100 , through the respective protrusions  100   p  provided on the substrate  100  in a one-to-one relationship. 
     The plurality of second routing lines RL 2  according to an embodiment may each include a side routing pattern SRP and a rear routing pattern RRP. 
     The side routing pattern SRP may be provided to surround half or less of each of the plurality of protrusions  100   p . That is, the side routing pattern SRP may be formed to fully surround approximate half of each of the plurality of protrusions  100   p  and may be provided through a dipping process using a conductive solution or a silver paste. 
     The rear routing pattern RRP may be provided in an edge of a rear surface  100   b  of the substrate  100  and may be electrically connected to the side routing pattern SRP. Also, the rear routing pattern RRP may be electrically connected to a first pad of a first pad part provided on the rear surface  100   b  of the substrate  100 . The rear routing pattern RRP may be provided through a printing process using a conductive paste, for example, a silver paste. 
     In addition, in the light emitting diode display device according to the present embodiment, the substrate  100  may further include a plurality of grooves, provided in a second non-display area overlapping ends of a plurality of gate lines, and a plurality of protrusions provided between the plurality of grooves. The plurality of second routing lines may be respectively provided in the plurality of protrusions in the same structure and method as the above-described plurality of first routing lines, and thus, their detailed descriptions are not repeated. 
       FIGS. 11A to 11C  are diagrams for describing a method of manufacturing the plurality of first routing lines illustrated in  FIG. 10 . 
     The method of manufacturing the plurality of first routing lines according to the present embodiment will be described with reference to  FIGS. 11A to 11C . 
     First, a substrate  100  including a plurality of pixel driving lines including a plurality of data lines DL may be provided. 
     Subsequently, as illustrated in  FIG. 11A , a plurality of grooves  100   c  may be formed through a substrate cutting process in order for ends of the plurality of data lines DL to protrude. The substrate cutting process according to an embodiment may cut a portion of an edge of the substrate  100  corresponding to a space between the plurality of data lines DL by using a laser scribing process to form a plurality of protrusions  100   p  overlapping the ends of the plurality of data lines DL. 
     Subsequently, as illustrated in  FIG. 11B , a plurality of side routing patterns SRP which respectively surround the plurality of protrusions  100   p  provided on the substrate  100  in a one-to-one relationship may be formed. For example, the plurality of side routing patterns SRP may be formed by a dipping process of dipping approximate half of each of the protrusions  100   p  into a conductive solution and coating the conductive solution on a front surface, a side surface, and a rear surface of each of the plurality of protrusions  100   p . By performing the dipping process, each of the plurality of side routing patterns SRP electrically and respectively connected to the plurality of data lines DL may be individually provided, and each of the plurality of side routing patterns SRP may be electrically separated from each other by the plurality of grooves  100   c  provided on the substrate  100 . Here, the conductive solution may include a conductive paste, for example, a silver paste. 
     Subsequently, as illustrated in  FIG. 11C , the plurality of rear routing patterns RRP which are respectively connected to the plurality of side routing patterns SPR in a one-to-one relationship may be formed on a rear surface  100   b  of the substrate  100 , thereby providing a plurality of first routing lines RL 1  including a side routing pattern SPR and a rear routing pattern RRP which are connected to the ends of the plurality of data lines DL and extend to the outer surface and the rear surface  100   b  of the substrate  100 . Here, the plurality of rear routing patterns RRP according to an embodiment may be provided through a printing process using a conductive paste. 
     In addition, in the light emitting diode display device according to the present embodiment, the plurality of second routing lines are provided by a manufacturing method which is the same as a method of manufacturing the plurality of first routing lines, and thus, description on the manufacturing method is not repeated. 
     By using the routing line and the method of manufacturing the same according to the present embodiment, a process of forming a routing line on the outer surface of the substrate  100  is simplified, electrical short circuit between adjacent routing lines is prevented, and a chamfer process or a rounding process for the edge of the substrate  100  may be omitted. 
       FIG. 12  is a cross-sectional view taken along line I-I′ illustrated in  FIG. 6  and illustrates an example where a color filter is added to the light emitting diode display device according to an embodiment of the present disclosure. Hereinafter, therefore, only an element added to the light emitting diode display device according to an embodiment of the present disclosure will be described. 
     Referring to  FIG. 12  along with  FIG. 6 , the light emitting diode display device according to the present embodiment may further include a black matrix BM and a color filter layer CFL. 
     First, a micro light emitting device  150  provided in each of a plurality of subpixels SP 1  to SP 3  may emit white light. That is, all the micro light emitting devices  150  provided on a substrate  100  may be white micro light emitting devices emitting white light. 
     The black matrix BM may define an opening area of each of the subpixels SP 1  to SP  3  and may be directly provided on a top  170   a  of a transparent buffer layer  170  which overlaps the micro light emitting device  150  of each of the subpixels SP 1  to SP 3  in a one-to-one relationship, thereby preventing color mixture between adjacent subpixels SP 1  to SP 3 . The black matrix BM may include a light absorbing material. 
     Optionally, the black matrix BM may be provided to cover side surface of the transparent buffer layer  170  and an outer surface of the substrate  100 . In this case, the black matrix BM prevents side light leakage while light emitted from the micro light emitting device  150  of each of the subpixels SP 1  to SP 3  travels in a direction from the inside of the transparent buffer layer  170  to an outermost surface. 
     The color filter layer CFL may be directly formed on a top  170   a  of the transparent buffer layer  170  overlapping the opening area defined by the black matrix BM and may include a red color filter CF 1 , a green color filter CF 2 , and a blue color filter CF 3  corresponding to respective colors defined in the plurality of subpixels SP 1  to SP 3 . The color filter layer CFL may transmit only light, having a wavelength of a color corresponding to a corresponding subpixel SP, of the white light emitted from each of the subpixels SP 1  to SP 3 . 
     In addition, the light emitting diode display device according to the present embodiment may further include a cover layer  190 . 
     The cover layer  190  may be provided on the substrate  100  to cover the black matrix BM and the color filter layer CFL. The cover layer  190  according to an embodiment may be formed of a material having a relatively low refractive index. For example, the cover layer  190  may be formed of LiF, MgF 2 , CaF 2 , ScF 3 , and/or the like and may have a multi-layer structure having different refractive indexes. The cover layer  190  may be provided on the substrate  100  to cover the black matrix BM and the color filter layer CFL, thereby protecting each of the subpixels SP 1  to SP 3  and efficiently outputting light, emitted from a micro light emitting device  150  of each of the subpixels SP 1  to SP 3 , to the outside. 
     Optionally, the light emitting diode display device according to the present embodiment may further include a side coating layer  109 . 
     The side coating layer  109  may be provided to cover an outer surface of the cover layer  109 . The side coating layer  109  according to an embodiment may be provided to cover the outer surface of the cover layer  190  through a coating process using a black ink including a black-based light absorbing material. Furthermore, the side coating layer  109  may be additionally provided on the outer surface of the substrate  100  and a side surface of the black matrix BM. The side coating layer  109  prevents side light leakage while light emitted from the micro light emitting device  150  of each of the subpixels SP 1  to SP 3  travels in a direction from the inside of the cover layer  190  to an outermost surface. 
     The cover layer  190  may be replaced with a transparent substrate including a glass material or a transparent plastic material, and in this case, the transparent substrate may be adhered to the black matrix BM and the color filter layer CFL by using a transparent adhesive member. Furthermore, the black matrix BM and the color filter layer CFL may be provided on the transparent substrate without being directly formed on a top  170   a  of the transparent buffer layer  170 , and in this case, the transparent substrate including the black matrix BM and the color filter layer CFL may be adhered to the top  170   a  of the transparent buffer layer  170  by using the transparent adhesive member. 
     As described above, in the present embodiment, since the micro light emitting devices  150  having the same color are respectively mounted on the subpixels SP 1  to SP 3 , a mounting process for the micro light emitting devices  150  may be performed without differentiating micro light emitting devices by colors, thereby shortening a mounting process time taken in the mounting process for the micro light emitting devices. 
       FIG. 13  is a cross-sectional view taken along line I-I′ illustrated in  FIG. 6  and illustrates an example where a wavelength conversion layer is added to the light emitting diode display device illustrated in  FIG. 12 . Hereinafter, therefore, the wavelength conversion layer and elements relevant thereto will be described. 
     Referring to  FIG. 13 , in the light emitting diode display device according to the present embodiment, if a micro light emitting device  150  emitting light of a first color except white is identically disposed in each of a plurality of subpixels SP 1  to SP 3 , a wavelength conversion layer  180  may be provided on a top of a transparent buffer layer  170 , for realizing colors through a plurality of unit pixels UP 1  and UP 2 . That is, the wavelength conversion layer  180  may be provided between the color filter layer CFL and the transparent buffer layer  170 . 
     The wavelength conversion layer  180  may emit light of a second color, based on the light of the first color incident from the micro light emitting device  150  of each of the subpixels SP 1  to SP 3 . That is, the wavelength conversion layer  180  may absorb the light of the first color and may emit the light of the second color through re-emission. Here, the light of the first color may be blue light, and the light of the second color may be yellow light. 
     For example, the wavelength conversion layer  180  may be directly coated on a top  170   a  of the transparent buffer layer  170  in a liquid state, and then, may be cured by a curing process using heat and/or light. As another example, the wavelength conversion layer  180  may be manufactured in a sheet form and may be directly adhered to the top  170   a  of the transparent buffer layer  170 . 
     The wavelength conversion layer  180  according to an embodiment may include a phosphor or a quantum dot. 
     The phosphor according to an embodiment may be a yellow phosphor which is excited by blue light to emit yellow light, and for example, may be an yttrium aluminum garnet (YAG)-based material. 
     The quantum dot according to an embodiment may be excited by blue light to emit yellow light and may have a size for emitting light having a yellow wavelength, and for example, may include CdS, CdSe, CdTe, ZnS, ZnSe, GaAs, GaP, GaAs—P, Ga—Sb, InAs, InP, InSb, AlAs, AlP, AlSb, and/or the like. 
     The light of the second color, which is re-emitted from the wavelength conversion layer  180  according to the present embodiment and is irradiated onto a cover layer  190 , may be combined with the light of the first color irradiated onto the second substrate  500  without being re-emitted from the wavelength conversion layer  180 , and thus, may be converted into white light. The white light may be filtered by a color filter overlapping each of the subpixels SP 1  to SP 3 , and thus, may be emitted as color light corresponding to each of the subpixels SP 1  to SP 3 . 
     Except that the black matrix BM and the color filter layer CFL are provided on the top  170   a  of the wavelength conversion layer  180 , the black matrix BM and the color filter layer CFL are the same as  FIG. 12 , and thus, their detailed descriptions are not repeated. 
     As described above, in the present embodiment, since the micro light emitting devices  150  having the same color are respectively mounted on the subpixels SP 1  to SP 3 , a mounting process for the micro light emitting devices  150  may be performed without differentiating micro light emitting devices by colors, thereby shortening a mounting process time taken in the mounting process for the micro light emitting devices. 
     The cover layer  190  may be replaced with a transparent substrate including a glass material or a transparent plastic material, and in this case, the transparent substrate may be adhered to the wavelength conversion layer  180  by using a transparent adhesive member. Furthermore, the wavelength conversion layer  180  may be provided on the transparent substrate without being directly be formed on a top  170   a  of the transparent buffer layer  170 , and in this case, the transparent substrate may be adhered to the top  170   a  of the transparent buffer layer  170  by using the transparent adhesive member. 
       FIG. 14  is a diagram for describing a multi-screen display device according to an embodiment of the present disclosure, and  FIG. 15  is a cross-sectional view taken along line II-II′ illustrated in  FIG. 14 . 
     Referring to  FIGS. 14 and 15  along with  FIG. 7 , the multi-screen display device according to the present embodiment may include a plurality of screen modules  500 - 1 ,  500 - 2 ,  500 - 3  and  500 - 4  and a housing  600 . 
     The plurality of screen modules  500 - 1  to  500 - 4  may be arranged in an NxM form (where N is a positive integer equal to or more than two, and M is a positive integer equal to or more than two) to respectively display individual images or divisionally display one image. The plurality of screen modules  500 - 1  to  500 - 4  may each include the light emitting diode display device according to the embodiments of the present disclosure illustrated in  FIGS. 1 to 13 , and a repetitive description on the light emitting diode display device is not provided. 
     Side surfaces of the plurality of screen modules  500 - 1  to  500 - 4  according to an embodiment may be coupled to each other by a module coupling member  700  provided on the outer surface of the substrate  100 . The module coupling member  700  may couple the side surfaces of two adjacent screen modules of the plurality of screen modules  500 - 1  to  500 - 4  arranged in a lattice form, thereby implementing the multi-screen display device. The module coupling member  700  according to an embodiment may be formed of an adhesive or a double-sided tape which enables a relatively thin thickness, for minimizing a space between two adjacent screen modules of the plurality of screen modules  500 - 1  to  500 - 4 . 
     In each of the plurality of screen modules  500 - 1  to  500 - 4 , a maximum distance L between the second unit pixel UP 2  and the outer surface of the substrate  100  may be half “P/2” or less of the reference pixel pitch P at which the plurality of first unit pixels UP 1  are arranged. Therefore, a maximum distance between second unit pixels UP 2  of two adjacent screen modules of which side surfaces are coupled to each other with the module coupling member  700  between the two adjacent screen modules may be equal to or less than the reference pixel pitch P. In other words, a pixel pitch between the second unit pixels UP 2  of two adjacent screen modules may be equal to or less than the reference pixel pitch P at which the first unit pixels UP 1  respectively provided in the plurality of screen modules  500 - 1  to  500 - 4  are arranged. Therefore, in the present embodiment, an area where a dark portion caused by a boundary portion between two adjacent screen modules of the screen modules  500 - 1  to  500 - 4  occurs is reduced or removed, and thus, an image where a sense of discontinuity of a whole screen is reduced or minimized may be displayed. 
     The housing  600  may support a rear edge of each of the plurality of screen modules  500 - 1  to  500 - 4  and may cover a rear surface of the plurality of screen modules  500 - 1  to  500 - 4 . The housing  600  according to an embodiment may include a housing plate  610 , covering the rear surface of each of the plurality of screen modules  500 - 1  to  500 - 4 , and a housing side wall  630  which is provided vertical to the housing plate  610  and supports the rear edge of each of the plurality of screen modules  500 - 1  to  500 - 4 . 
     The housing plate  610  according to an embodiment may be configured as one body covering the whole rear surface of each of the plurality of screen modules  500 - 1  to  500 - 4 . 
     The housing plate  610  according to an embodiment may be configured with a plurality of division plates to overlap the rear surface of each of the plurality of screen modules  500 - 1  to  500 - 4 . 
     The housing side wall  630  may be installed vertical to a top of the housing plate  610  overlapping the rear edge of each of the plurality of screen modules  500 - 1  to  500 - 4  and may individually support the rear edge of each of the plurality of screen modules  500 - 1  to  500 - 4 . In this case, the housing side wall  630  may support the rear edge of each of the plurality of screen modules  500 - 1  to  500 - 4  through a module supporting member  650 . Here, the module supporting member  650  may be an elastic member, a foam pad, a double-sided tape, or the like. 
     In addition, the housing  600  may include a plurality of module housings including the housing plate  610  and the housing side wall  630 . Each of the plurality of housing modules may individually support the rear edges of the plurality of screen modules  500 - 1  to  500 - 4  and may cover the rear surfaces of the plurality of screen modules  500 - 1  to  500 - 4 . In this case, the housing  600  may include a housing coupling member  800  provided between the plurality of module housings. The housing coupling member  800  may be inserted into a space between adjacent module housings and may be fixed to the housing plate  610  of each of adjacent module housings by a fastening member such as a bolt, a screw, and/or the like. 
     In addition, the multi-screen display device according to the present embodiment may further include an integration control board  900  and an image signal generator  910  mounted on the integration control board  900 . 
     The integration control board  900  may be disposed in an accommodating space provided on the rear surface of each of the plurality of screen modules  500 - 1  to  500 - 4  by the housing  600 . The integration control board  900  may be connected to the control board  250  of each of the plurality of screen modules  500 - 1  to  500 - 4  through at least one signal cable  930 . 
     The image signal generator  910  may be mounted on the integration control board  900 . The image signal generator  910  may receive a raw image signal supplied from an external host driving system and may generate a module-based input image signal corresponding to each of images which are to be respectively displayed by display devices of the plurality of screen modules  500 - 1  to  500 - 4 , based on the received raw image signal. That is, the image signal generator  910  may receive all resolution information, including a first display area AA 1  and a second display area AA 2 , about each of the plurality of screen modules  500 - 1  to  500 - 4 , divide the raw image signal according to the resolution information about each module to generate the module-based input image signal, and supply the module-based input image signal to a corresponding screen module of the plurality of screen modules  500 - 1  to  500 - 4 . Therefore, each of the plurality of screen modules  500 - 1  to  500 - 4  may display a module-based image corresponding to module-based panel image data, based on the input image signal supplied from the image signal generator  910 . 
     As described above, since the multi-screen display device according to the present embodiment includes the screen modules  500 - 1  to  500 - 4  configured with the light emitting diode display device according to the embodiments of the present disclosure, an area where a dark portion caused by a boundary portion between two adjacent screen modules of the screen modules  500 - 1  to  500 - 4  occurs is reduced or removed, and thus, an image where a sense of discontinuity of a whole screen is reduced or minimized may be displayed. 
       FIG. 16A  is a multi-screen display device of the related art 
       FIG. 16B  is a multi-screen display device according to an embodiment of the present disclosure. 
     First, referring to  FIG. 16A , in the related art multi-screen display device, since an image is displayed on only a display area AA of each of a plurality of display devices, it can be seen that due to a bezel area BA based on a front case of each of the plurality of display devices, a dark portion occurs in a boundary portion between display devices coupled to each other, and a disconnected image caused by the dark portion of the boundary portion is displayed in a whole screen. 
     On the other hand, referring to  FIG. 16B , in the multi-screen display device according to the embodiments of the present disclosure, since a pixel pitch between second unit pixels of two adjacent screen modules of which side surfaces are coupled to each other is equal to or less than a reference pixel pitch of a first unit pixel, it can be seen that an area where a dark portion caused by a boundary portion between a plurality of screen modules occurs is reduced or removed, and thus, an image where a sense of discontinuity of a whole screen is reduced or minimized is displayed. 
     As a result, even in a case where side surfaces of a plurality of screen modules are coupled to each other in a lattice form, the multi-screen display device according to the embodiments of the present disclosure may display one image where a sense of discontinuity of a whole screen is reduced or minimized, thereby enhancing a degree of viewing immersion of a user for an image displayed on a large-size screen. 
     As described above, according to the embodiments of the present disclosure, a light emitting diode display device having a bezel width suitable for minimizing a boundary portion between display devices coupled to each other in a multi-screen display device is provided, and alignment precision and productivity are enhanced in a mounting (or transfer) process for a micro light emitting device. 
     Moreover, according to the embodiments of the present disclosure, one image where a sense of discontinuity of a whole screen is reduced or minimized is displayed even in a case where side surfaces of a plurality of screen modules are coupled to each other in a lattice form, thereby enhancing a degree of viewing immersion of a user for an image displayed on a large-size screen. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosures. Thus, it is intended that the present disclosure covers the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents. 
     The various embodiments described above can be combined to provide further embodiments. Further changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.