Patent Publication Number: US-2023143381-A1

Title: Electronic device and method for manufacturing the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of Application Ser. No. 16/720,917, filed Dec. 19, 2019, the entirety of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The application relates in general to a method of manufacturing an electronic device, and in particular to a method that includes a step of transferring a plurality of light-emitting units. 
     Description of the Related Art 
     Thanks to ongoing technological developments, recent electronic devices such as high-quality display screens usually include a plurality of LED (Light-emitting Diode) chips, which can provide 4K image quality. However, during the manufacturing of such electronic devices, the higher the desired display quality, the more LED chips are required. For example, a 4K display screen has more than 24 million LED chips. It means that there are many LED chips that need to be transferred and set on a driving substrate. Therefore, how to provide a way to efficiently transfer LED chips from a carrier substrate to a driving substrate is an important issue. 
     BRIEF SUMMARY OF INVENTION 
     To address the deficiencies of conventional products, an embodiment of the disclosure provides a method of manufacturing an electronic device, comprising: providing a carrier substrate with a plurality of light-emitting units disposed thereon, the plurality of light-emitting units being spaced with a first pitch (P 1 ) in a first direction and a second pitch (P 2 ) in a second direction that is perpendicular to the first direction; providing a driving substrate; and transferring at least a portion of the plurality of light-emitting units to the driving substrate to form a transferred portion of the plurality of light-emitting units on the driving substrate, the transferred portion being spaced with a third pitch (P 3 ) in a third direction and a fourth pitch (P 4 ) in a fourth direction perpendicular to the third direction; wherein the first pitch (P 1 ), the second pitch (P 2 ), the third pitch (P 3 ), and the fourth pitch (P 4 ) are satisfied following relations: P 3 =mP 1 ; and P 4 =nP 2 , m and n are positive integers. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG.  1    is a schematic diagram of a system of manufacturing an electronic device according to an embodiment of the present disclosure. 
         FIG.  2 A  is a schematic diagram of a system of manufacturing an electronic device according to another embodiment of the present disclosure. 
         FIG.  2 B  is a schematic diagram of a system of manufacturing an electronic device according to another embodiment of the present disclosure. 
         FIG.  2 C  is a schematic diagram of a method of manufacturing an electronic device according to another embodiment of the present disclosure. 
         FIGS.  3 A to  3 D  are schematic diagrams of the light-emitting units transferred to the driving substrate from the carrier substrate according to another embodiment of the present disclosure. 
         FIG.  4 A  is a schematic and cross-sectional diagram of the light-emitting units, the buffer layer and the carrier substrate. 
         FIG.  4 B  is a schematic diagram of the light-emitting units having different heights. 
         FIG.  5    is a schematic diagram of the light-emitting units transferred to the driving substrate from the carrier substrates according to another embodiment of the present disclosure. 
         FIG.  6    is a schematic diagram of the light-emitting units transferred to the driving substrate from the carrier substrate according to another embodiment of the present disclosure. 
         FIGS.  7 A to  7 E  are schematic diagrams of the light-emitting units transferred to the driving substrate from the carrier substrates according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The making and using of the embodiments of the methods of manufacturing an electronic device are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the embodiments, and do not limit the scope of the disclosure. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be appreciated that each term, which is defined in a commonly used dictionary, should be interpreted as having a meaning conforming to the relative skills and the background or the context of the present disclosure, and should not be interpreted in an idealized or overly formal manner unless defined otherwise. 
     It should be noted that the electronic device may include a display device, an antenna device, a sensing device, or a tiled device, but is not limited thereto. The electronic device can be a bendable or flexible electronic device. The electronic device may include, for example, a light-emitting diode; the light-emitting diode may include, for example, an organic light-emitting diode (OLED), a sub-millimeter light-emitting diode (mini LED), and a micro light-emitting diode (micro LED) or a quantum dot (QD) light-emitting diode (which may be, for example, QLED or QDLED), fluorescence, phosphor, or other suitable material, and the materials thereof may be arbitrarily arranged and combined, but is not limited thereto. The antenna device can be, for example, a liquid crystal antenna, but is not limited thereto. The tiled device can be, for example, a display tiled device or an antenna tiled device, but is not limited thereto. It should be noted that the electronic device may be any combination of the foregoing, but is not limited thereto. 
     First Embodiment 
     Referring to  FIG.  1   ,  FIG.  1    is a schematic diagram of a system  100  of manufacturing an electronic device. The system  100  comprises at least one carrier substrate  11  and a driving substrate  20 . In the present embodiment, the carrier substrate  11  is a processing-transition substrate which can holds the light-emitting units  111 . The driving substrate  20  may be an AM (Active Matrix, ex. array substrate with TFT) substrate or a PM (Passive Matrix) substrate, which can be used to a substrate of a display device. A plurality of light-emitting units  111  (such as LED chips) are disposed on the carrier substrate  11 , wherein the light-emitting units  111  are transferred from the carrier substrate  11  to the driving substrate  20 , for example, by way of adhesive (e.g. carrier substrate  11  and driving substrate  20  are attached to each other) or via a gripping head (e.g. a transferring member  30  in FIG. 7 D). In some embodiments, the driving substrate  20  has stronger adhesion to the light-emitting units  111  than the carrier substrate  11 . When the carrier substrate  11  and the driving substrate  20  are attached together (with the light-emitting units  111  between them), the light-emitting units  111  can be transferred to the driving substrate  20  from the carrier substrate  11 . In some embodiments, light-emitting unit  111  may be a single color light-emitting unit, such as a red, green or blue light-emitting unit, or it can be an integrated RGB light-emitting unit. 
     Regarding to the light-emitting units  111  on the carrier substrate  11 , the two adjacent light-emitting units  111  being spaced from each other with a first pitch P 1  in a first direction D 1  (X-axis) and a second pitch P 2  in a second direction D 2  (Y-axis) different from the first direction D 1 . In one embodiment, the second direction D 2  is perpendicular to the first direction Dl. By using an adhesion or a gripping head, the light-emitting units  111  can be transferred and disposed on the driving substrate  20  to form a transferred portion of the light-emitting units (transferred light-emitting units)  111 ′. It should be note that the two adjacent transferred light-emitting units  111 ′ is spaced from each other with a third pitch P 3  in a third direction D 3  (X-axis) and a fourth pitch P 4  in a fourth direction D 4  (Y-axis) different from the third direction D 3 . In one embodiment, the fourth direction D 4  is perpendicular to the third direction D 3 . In this embodiment, the pitches P 3  and P 4  of the light-emitting units  111 ′ are respectively equal to the pitches P 1  and P 2  of the light-emitting units  111 . 
     In some embodiments, the system  100  of manufacturing an electronic device may further comprises another carrier substrate  12 , also shown in  FIG.  1   . The light-emitting units  111  and  121  on the respectively carrier substrates  11  and  12  can be transferred to the same driving substrate  20 , that is the transferred light-emitting units  111 ′ and  121 ′. Therefore, it means that the driving substrate  20  can carry a plurality of light-emitting units which are transferred from different carrier substrates. 
     According to the carrier substrate area and driving substrate area for light-emitting units, and the densities of light-emitting units in carrier substrate  11  and driving substrate  20 , the amount of carrier substrates can be found by: 
     
       
         
           
             
               
                 
                   
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                         d 
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                         2 
                       
                     
                   
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                       A 
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                       2 
                     
                     
                       A 
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                       1 
                     
                   
                 
               
               
                 
                   ( 
                   1 
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     In the formula (1), “d 1 ” and “d 2 ” represent the “light-emitting units density on the carrier substrate” and the “light-emitting units density on the driving substrate”; “A 1 ” and “A 2 ” represent the “area occupied by the light-emitting units on the carrier substrate” and the “area occupied by the light-emitting units on the driving substrate area”; and “y” represents the amount of carrier substrates. Therefore, by this formula (1), the required quantity for carrier substrates can be calculated. 
     Second Embodiment 
     In some embodiments, a portion of the light-emitting units  111  are transferred, and the pitches P 3  and P 4  may not totally equal to the pitches P 1  and P 2 . For example, in  FIG.  2 A , the light-emitting units  111  on the carrier substrate  11  has the first pitch P 1  (X-axis) and the second pitch P 2  (Y-axis). After the light-emitting units  111  have been transferred, the transferred light-emitting units  111 ′ on the driving substrate  20  has the third pitch P 3  (X-axis) and the fourth pitch P 4  (Y-axis), wherein P 3  is twice as large as P 1  (i.e. P 3 = 2 P 1 ), and P 4  is twice as large as P 2  (i.e. P 4 = 2 P 2 ). Therefore, by transferring the light-emitting units which are located at specific positions, the pitches (P 3  and P 4 ) of the transferred light-emitting units can be adjusted. 
     In some embodiments, as shown in  FIG.  2 B , the transferred light-emitting units  111 ′ on the driving substrate  20  has the third pitch P 3  (X-axis) and the fourth pitch P 4  (Y-axis), wherein P 3  is twice as large as P 1  (i.e. P 3 = 2 P 1 ), and P 4  is same to P 2  (i.e. P 4 =P 2 ). In some embodiments, the P 3  can be a positive integer multiple of P 1 , and P 4  can be a positive integer multiple of P 2 . By transferring the light-emitting units which are located at specific positions, the pitches (P 3  and P 4 ) of the transferred light-emitting units can be adjusted. Therefore, by adjusting the pitches (different directions) of the transferred light-emitting units, the electronic device is more flexible in the manufacturing process which can improve the process efficiency or the product quality. 
     According to the description of the foregoing embodiments, including the first and second embodiments, the present disclosure provides a method for manufacturing an electronic device  900 , as shown in  FIG.  2 C , which mainly includes: providing a carrier substrate with a plurality of light-emitting units disposed thereon, the plurality of light-emitting units being spaced with a first pitch (P 1 ) in a first direction and a second pitch (P 2 ) in a second direction perpendicular to the first direction (step  902 ); providing a driving substrate (step  904 ); and transferring at least a portion of the plurality of light-emitting units to the driving substrate to form a transferred light-emitting units on the driving substrate, the transferred light-emitting units being spaced with a third pitch (P 3 ) in a third direction and a fourth pitch (P 4 ) in a fourth direction perpendicular to the third direction; wherein the first pitch (P 1 ), the second pitch (P 2 ), the third pitch (P 3 ), and the fourth pitch (P 4 ) satisfy following relations:P 3 =mP 1 ; and P 4 =nP 2 , m and n are positive integers (step  906 ). 
     In step  902 , the light-emitting units are spaced with the first and second pitches P 1  and P 2 . In step  906 , the transferred light-emitting units are spaced with the third and fourth pitches P 3  and P 4 , wherein P 3 =mP 1 ; and P 4 =nP 2 , wherein m and n are positive integers. In some embodiments, m is equal to n; or m and n are all equal to 1. In some embodiments, the step of transferring at least a portion of the plurality of light-emitting units is via non-selective transferred (m and n are all equal to 1). In some embodiments, at least one of m and n is greater than 1. In some embodiments, m is different from n. In some embodiments, the step of transferring at least a portion of the plurality of light-emitting units is via selective transferred (at least one of m and n is greater than 1). 
     Third Embodiment 
       FIGS.  3 A to  3 D  show schematic diagrams of the light-emitting units  111  on the carrier substrate  11  undergoing a plurality of transferring processes. As shown in FIG. 3 A, a portion of the light-emitting units  111  labeled with “First transferred” are selected to be transferred to the driving substrate  20  as the first transferred light-emitting units T 1 . Then, as shown in  FIG.  3 B , the other labeled “Second transferred” light-emitting units  111  are selected to be transferred to the driving substrate  20  as the second transferred light-emitting units T 2 . After then, as shown in  FIGS.  3 C and  3 D , the third transferred light-emitting units T 3  and the fourth transferred light-emitting units T 4  are sequentially transferred from the carrier substrate  11  to the driving substrate  20 . 
     By selective transferring process, the light-emitting units  111  are successfully transferred to the driving substrate  20  with the pitch P 3  in the X-axis and the pitch P 4  in the Y-axis. In this embodiment, P 3 = 2 P 1  and P 4 = 2 P 2 . 
     Fourth Embodiment 
     In some embodiments, before the light-emitting unit  111  to be transferred, there is a buffer layer  1100  formed between the light-emitting units  111  and the carrier substrate  11 , as shown in  FIG.  4 A . The buffer layer  1100  may comprise inorganic material or organic material. In some embodiments, the inorganic material may include, but is not limited to, silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide. In some embodiments, the organic material may include, but is not limited to, epoxy resins, acrylic resins such as polymethylmetacrylate (PMMA), benzocyclobutene (BCB), polyimide, and polyester, polydimethylsiloxane (PDMS) or polyfluoroalkoxy (PFA). The buffer layer  1100 , for example, can be formed via an etching process and has a plurality of regions with different heights in a fifth direction D 5  (Z-axis). 
     In the present embodiment, the buffer layer  1100  has a plurality of regions  1100 A to  1100 D, wherein different regions have different heights in a fifth direction D 5  (Z-axis) perpendicular to the first and second directions. In particular, as the cross-regional view along the line A-A′ (shown in  FIG.  4 A ), the buffer layer  1100  in the region  1100 A (between the carrier substrate  11  and the First transferred) has the largest height in the Z-axis. The heights of the buffer layer  1100  respectively in the regions  1100 B/ 1100 C (between the carrier substrate  11  and the Second transferred and the Third transferred) are smaller than the height of the buffer layer  1100  in the region  1100 A. The buffer layer  1100  in the region  1100 D (between the carrier substrate  11  and the Fourth transferred) has the lowest height in the Z-axis. 
     In some embodiments, the buffer layer can be a multi-layer structure which is provided between the light-emitting units  111  and the carrier substrate  11 , which also forms a plurality of regions with different heights in Z-axis. In some embodiments, the region  1100 D may have one buffer layer; the region  1100 C may have two buffer layers; the region  1100 B may have three buffer layers; and the region  1100 A may have four buffer layers, but is not limited thereto. 
     With this configuration, a portion of the light-emitting units  111  on the carrier substrate  11  can easily be selected to transfer to the driving substrate  20 . For example, by way of adhesion, the two substrates  11  and  20  may be attached to each other to transfer the light-emitting units  111 , due to different heights of the buffer layer  1100  in different regions  1100 A to  1100 D, the first transferred light-emitting units T 1  can be transferred to a specific area of the driving substrate  20 . Then the second transferred light-emitting units T 2 , the third transferred light-emitting units T 3  and the fourth transferred light-emitting units T 4  are sequentially transferred to others specific areas of the driving substrate  20 . 
     In some embodiments, light-emitting units labeled “First transferred”, “Second transferred”, “Third transferred”, and “Fourth transferred” may have different heights in the Z-axis by different way. As shown in  FIG.  4 B , light-emitting units  111  has multiple layers: a p-type semiconductor layer  1111 , a multiple quantum well (MQW) layer  1112 , an n-type semiconductor layer  1113 , and an i-type semiconductor layer  1114 , wherein the i-type semiconductor layer  1114  is located at the top portion of the light-emitting units  111 . In the present embodiment, the i-type semiconductor layer  1114  of the light-emitting unit labeled “First transferred” is thicker than the i-type semiconductor layer  1114  of the light-emitting unit labeled “Second transferred”. In the present embodiment, the i-type semiconductor layer  1114  of the light-emitting unit labeled “Second transferred” is thicker than the i-type semiconductor layer  1114  of the light-emitting unit labeled “Third transferred”. In the present embodiment, the i-type semiconductor layer  1114  of the light-emitting unit labeled “Third transferred” is thicker than the i-type semiconductor layer  1114  of the light-emitting unit labeled “Fourth transferred”. Therefore, with this configuration, it is possible to achieve an efficient transfer, which the light-emitting units can be easily to select with the different heights. 
     Fifth Embodiment 
       FIG.  5    shows a plurality of the light-emitting units  111 ,  121  and  131  on the carrier substrates  11 ,  12  and  13  are transferred to the driving substrate  20 . The different carrier substrates  11  to  13  may sustain different types of light-emitting units. For example, the light-emitting units  111  may be (but not limit to) red light-emitting units; the light-emitting units  121  may be green light-emitting units; and the light-emitting units  131  may be blue light-emitting units. The different light-emitting units  111 ,  121  and  131  are depicted with different types of diagonal lines for clarity. The selected light-emitting units  111  (or  121 ,  131 ) to be transferred are represented by different frame lines relative to the unselected light-emitting units  111  (or  121 ,  131 ). 
     A portion of the same light-emitting units  111 ( 121  or  131 ) on the carrier substrate  11 ( 12  or  13 ) is transferred to the driving substrate  20  to become the light-emitting units  111 ′ ( 121 ′ or  131 ′), wherein the pitches P 1  and P 2  is less than the pitches P 3  and P 4  for same type of the light-emitting units  111 ( 121  or  131 ). In this embodiment, P 3 = 2 P 1 , and P 4 = 2 P 2 . 
     In some embodiments, the light-emitting units  111  are blue light-emitting units, the light-emitting units  121  are green light-emitting units, and the light-emitting units  131  are red light-emitting units. The light-emitting units  131  are transferred to the driving substrate  20  after the light-emitting units ( 111  and  121 ), due to the red light-emitting units are thicker than the blue and green light-emitting units. Therefore, the situation of the impact during transfer can be effectively decreased. In this embodiment, since the transferring member  30  may select the light-emitting units ( 111 ,  121  and  131 ) at different positions on different carrier substrates ( 11 ,  12  and  13 ) and transfer to the driving substrate  20 , the transferring member  30  can correctly place the light-emitting units as long as the transferring member  30  correspond to a fixed position of the driving substrate  20 . Furthermore, the transferring member  30  can also select the light-emitting units ( 111 ,  121  and  131 ) at the same position on different carrier substrates ( 11 ,  12  and  13 ) and transfer to the driving substrate  20 . At this time, the transferring member  30  can correctly place the light-emitting units ( 111 ,  121  and  131 ) on the driving substrate  20  as long as there is a displacement corresponding to the fixed position of the driving substrate  20 . 
     In addition, in order to make an electronic device with a larger size, the light-emitting units can be arranged on the temporary carrier substrate by using the method in Fifth Embodiment, and then transferred to the driving substrate by using the method in First Embodiment. 
     Sixth Embodiment 
       FIG.  6    illustrates the light-emitting units  111  transferred to the driving substrate  20  according to another embodiment of the present disclosure. The light-emitting units  111  include different types (such as different colors) of light-emitting units  111 R,  111 G and  111 B, which are depicted with different types of diagonal lines for clarity. The selected light-emitting units  111  to be transferred are represented by different frame lines relative to the unselected light-emitting units  111 . 
     First, the method involves selecting a portion of the light-emitting units  111 , labeled as First transferred, including light-emitting units  111 R,  111 G and  111 B with a triangle arrangement, and being an assembled portion of the light-emitting units TT 1 , and then transferring the assembled portion of the light-emitting units TT 1  to the driving substrate  20  as the first transferred light-emitting units Ti (including light-emitting units  111 ′R,  111 ′G and  111 ′B), having pitches P 3 =P 1  and P 4 =P 2 . Second, the method involves selecting another portion of the light-emitting units  111 , labeled as Second transferred, including units  111 R′,  111 G′ and  111 B′, and being an assembled portion of the light-emitting units TT 2 , and then rotating the assembled portion of the light-emitting units TT 2  by  180  degrees around the rotating direction R 1  and transferring the assembled portion of the light-emitting units TT 2  to the driving substrate  20  as the second transferred light-emitting units T 2 , having pitches P 3 =P 1  and P 4 =P 2 . 
       FIG.  6    illustrates a space S which is existed in the assembled portion of the light-emitting units TT 1  and TT 2 . If the light-emitting units via the first transfer can be divided into three times and transfers to a temporary carrier substrate respectively, the space can be removed. And then the light-emitting units on the temporary carrier substrate can be transferred to the driving substrate  20  by the transfer method as shown in First Embodiment. 
     Seventh Embodiment 
       FIGS.  7 A to  7 E  illustrate a way of light-emitting units  711  transferred to a driving substrate  20  according to another embodiment of the present disclosure. The light-emitting units  711  may be single color light-emitting units or integrated light-emitting units (such as RGB LED). As shown in  FIG.  7 A , from a cross-section view along the line B-B′, there is a sacrificial layer  80  between a carrier substrate  71  and the light-emitting units  711 . The sacrificial layer  80  may have a taper-shaped formed through a photolithography process, and may mainly comprise a photoresist material, for example, including a positive photoresist, such as phenol-formaldehyde resin or epoxy resin, or including a negative photoresist, such as polyisoprene rubber. The sacrificial layer  80  may also be formed through a photolithography process and chemical etchant processes, which may have inorganic material, such as including (but is not limited to) silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide, or may have an organic material, such as including (but is not limited to) epoxy resins, acrylic resins such as polymethylmetacrylate (PMMA), benzocyclobutene (BCB), polyimide, and polyester, polydimethylsiloxane (PDMS), or polyfluoroalkoxy (PFA). 
     Referring to  FIG.  7 B  shown as a top view and a cross-section view along the line C-C′, a holding layer  90  is provided over the light-emitting units  711  to hold the light-emitting units  711 , wherein the holding layer  90  also covers the sacrificial layer  80  and a portion surface of the carrier substrate  71  between the two adjacent light-emitting units  711 . The holding layer  90  primarily includes inorganic materials such as SiOx, SiNx, SiOxNy, AlOx, or metal. 
     Referring to  FIG.  7 C , the sacrificial layer  80  is etched in a wet etching process. The light-emitting units  711  are held by the holding layer  90 . After then, as shown in  FIG.  7 D , the holding layer  90  with the light-emitting units  711  is held by a transferring member  30 . The transferring member  30  may have a vacuum adsorption head, a gripping head, a magnetic head, a viscous film (such as a PDMS (polydimethylsiloxane) soft film or a PMMA (polymethylmethacrylate) soft film), or other appropriate transferring members, and the holding layer  90  fractures at a weak portion, e.g. a neck portion (the portion that does not cover any light-emitting unit  711  in the normal direction of the carrier substrate  71 ), to form a first portion  91  (grabbed by the transferring member  30 ) and a second portion  92  (still disposed on the carrier substrate  71 ), and the first portion  91  of the holding layer  90  and the light-emitting units  711  are separated from the carrier substrate  71 . 
     Referring to  FIG.  7 E , the transferring member  30  places the light-emitting units  711  on the driving substrate  20 , wherein the light-emitting units  711  are connected to a conductive layer EC. A conductive test is performed via a testing member ER to identify the bonding quality of the light-emitting units  711 . In some embodiments, the lower surface of the first portion  91  may be higher than or equal to the lower surface of the electrodes  711 E of the light-emitting units  711 . And, the first portion  91  will couple to the electrodes  711 E, thereby improving product yield. After the testing is passed, the connection between the light-emitting units  711  and the conductive layer EC is covered by a package member PK, and at least a portion of the light-emitting units  711  are compassed by the package member PK. In some embodiments, the first portion  91  can be fully covered by the package member PK to achieve good encapsulation. 
     It should be noted that the features of the various embodiments can be combined and used as long as they do not violate or conflict the scope of the disclosure. 
     In summary, the present disclosure provides a method of manufacturing an electronic device. The embodiment of the present disclosure has at least one of the following advantages or effects. The pitches (P 3  and P 4 ) can be changed, which are larger than or equal to the pitches (P 1  and P 2 ). Therefore, the pitch of a large number of the light-emitting units can be rapidly adjusted, or the transfer efficiency can be increased, or the manufacturing process is improved. 
     Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosure. It is intended that the standard and examples be considered as exemplary only, with the true scope of the disclosed embodiments being indicated by the following claims and their equivalents.