Abstract:
A fingerprint identification device includes a fingerprint identification controller and a fingerprint identification sensor. The fingerprint identification sensor includes a substrate having a top surface, a bottom surface opposite to the top surface, and a side surface coupled between the top surface and the bottom surface. Sensor electrodes are arranged on the top surface, electrical leads couple the sensor electrodes and the fingerprint identification controller. The coupling leads extend from the top surface along the side surface to the bottom surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Patent Application No. 201510135464.8 filed on Mar. 26, 2015 in the China Intellectual Property Office, the contents of which are incorporated by reference herein. 
       FIELD 
       [0002]    The subject matter herein generally relates to a fingerprint identification device and a manufacturing method of the fingerprint identification device. 
       BACKGROUND 
       [0003]    A fingerprint identification device can be an optical identification device, a resistive identification device, or a capacitive identification device. The capacitive identification device can include a plurality of sensor electrodes arranged on a substrate and a plurality of leads to transmit signals from the plurality of sensor electrodes. The quantity of the leads increases as higher resolution of fingerprint identification is required. Thus, when a finger touches the capacitive identification device, the leads arranged around the sensor electrodes are prone to generate signal interference. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0005]      FIG. 1  is an isometric view of a fingerprint identification device according to the present disclosure. 
           [0006]      FIG. 2  is a cross sectional view of the fingerprint identification device of  FIG. 1  taken along line II-II of  FIG. 1 . 
           [0007]      FIG. 3  is an enlarged view of circled part III of  FIG. 2 . 
           [0008]      FIG. 4  is an exploded view of the fingerprint identification device of  FIG. 1 . 
           [0009]      FIG. 5  is a flowchart of a manufacturing method of the fingerprint identification device according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features. The description is not to be considered as limiting the scope of the embodiments described herein. 
         [0011]    Several definitions that apply throughout this disclosure will now be presented. 
         [0012]    The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
         [0013]      FIG. 1  illustrates a fingerprint identification device  10  utilizing capacitive fingerprint identification. The fingerprint identification device  10  defines a contact sensing surface  191  touchable by external objects such as a finger of a user. 
         [0014]      FIGS. 2-4  illustrate that the fingerprint identification device  10  can include a contact protection layer  190 , a fingerprint identification sensor  100 , and a fingerprint identification controller  180 . The contact protection layer  190  covers the fingerprint identification sensor  100  to protect the fingerprint identification sensor  100 . A surface of the contact protection layer  190  is defined as the contact sensing surface  191 . The fingerprint identification sensor  100  is located on the fingerprint identification controller  180  and electrically coupled to the fingerprint identification controller  180 . When the contact sensing surface  191  is touched, the fingerprint identification sensor  100  senses fingerprint information and transmits the fingerprint information to the fingerprint identification controller  180 . The fingerprint identification controller  180  can include a plurality of interfaces  181  to receive the fingerprint data. 
         [0015]    The contact protection layer  190  can be an anti-fingerprint (AF) film made of carbon matrix composite such as diamond-like carbon (DLC) and amorphous diamond. In the embodiment, the fingerprint identification controller  180  can be an application specific integrated circuit (ASIC). 
         [0016]    The fingerprint identification sensor  100  can include a conductive layer  150 , a first insulating layer  140 , a plurality of sensor electrodes  120 , a substrate  110 , a plurality of leads  130 , a protection adhesive  170 , and a second insulating layer  160 . 
         [0017]    The substrate  110  can include a top surface  111 , a bottom surface  112  opposite to the top surface  111 , and a side surface  113  coupled between the top surface  111  and the bottom surface  112 . In the embodiment, the substrate  110  can be made of strengthened glass, toughened glass, ceramic, sapphire, PET, or FPC. 
         [0018]    The plurality of sensor electrodes  120  are arrayed on the top surface  111 . The fingerprint identification controller  180  is located below the bottom surface  112 . The plurality of leads  130  are arranged on the substrate  110 . One end of each of the plurality of leads  130  is electrically coupled to a sensor electrode  120 , and the other end of each of the plurality of leads  130  is electrically coupled to a controller interface  181 . 
         [0019]    In detail, the one end of each of the plurality of leads  130  extends along the side surface  113  to the top surface  111  to couple with the sensor electrodes  120 , while the other end of each of the plurality of leads  130  extends along the side surface  113  to the bottom surface  112 , to couple with the controller interface  181 . The other end of each of the plurality of leads  130  can include a connecting pad  131  to couple with the controller interface  181 . 
         [0020]    The protection adhesive  170  covers the plurality of leads  130  to fix and protect the plurality of leads  130 . In the embodiment, the protection adhesive  170  can be polymethyl methacrylate (PMMA) or epoxy resin. A thickness of the protection adhesive  170  is about 10-100 micrometers. The second insulating layer  160  covers the bottom surface  112  except for the plurality of connecting pads  131 . In the embodiment, the plurality of leads  130  can be made of indium tin oxide (ITO), silver (Ag), copper (Cu), gold (Au), or aluminium (Al). 
         [0021]    The plurality of sensor electrodes  120  is arranged in two columns. A width of each electrode of the plurality of sensor electrodes  120  is about 20-200 micrometers. In the embodiment, the sensor electrodes  120  can be made of indium tin oxide (ITO), zinc oxide (ZnO), carbon nanotubes (CNT), silver nanowire, or grapheme. 
         [0022]    The first insulating layer  140  covers the plurality of sensor electrodes  120 . The first insulating layer  140  and the second insulating layer  160  can be made of the same material. 
         [0023]    The conductive layer  150  is arranged on the first insulating layer  140 . The conductive layer  150  defines a plurality of openings  151  corresponding to the plurality of sensor electrodes  120 . A size of each of the plurality of the openings  151  is larger than a size of each electrode of the plurality of sensor electrodes  120 . A gap (as shown in  FIG. 3 ) D is defined from a side edge of the opening  151  to an edge of a sensor electrode  120  facing the side edge of the opening  151 . In the embodiment, a width of the gap D is 0-30 micrometers. A width of the each opening of the plurality of openings  151  is 80-260 micrometers. In the embodiment, the openings  151  are formed by yellow light etching or laser etching. 
         [0024]    The conductive layer  150  is grounded to prevent signal interference when the finger touches the top surface  111 . The conductive layer  150  is electrically coupled to a ground pin of the controller interface  181 . 
         [0025]    The contact protection layer  190  covers the conductive layer  150  and the plurality of sensor electrodes  120 . The protection adhesive  170  is located between the contact protection layer  190  and the second insulating layer  160  to protect the leads  130 . 
         [0026]    A change in equivalent capacitance between a fingerprint ridge and a fingerprint valley causes a capacitance change when the contact sensing surface  191  is touched by a finger. A fingerprint ridge or fingerprint valley can be identified by the sensor electrodes  120  according to the capacitance change, thereby obtaining fingerprint data of the finger. The sensor electrodes  120  transmit the fingerprint data to the fingerprint identification controller  180 . 
         [0027]      FIG. 5  illustrates a flowchart of the manufacturing method of the fingerprint identification device. The method is provided by way of example, as there are a variety of ways to carry out the method. Each block shown in  FIG. 5  represents one or more processes, methods, or subroutines which are carried out in the example method. Furthermore, the order of blocks is illustrative only and the order of the blocks can change. Additional blocks can be added or fewer blocks may be utilized without departing from the scope of this disclosure. The example method can begin at block  401 . 
         [0028]    At block  501 , a substrate  110  is provided. The substrate  110  can include a top surface  111 , a bottom surface  112  opposite to the top surface  111 , and a side surface  113  coupled between the top surface  111  and the bottom surface  112 . 
         [0029]    At block  502 , a first conductive film is formed in the top surface  111  of the substrate  110 , and is patterned to form a plurality of the sensor electrodes  120  and the leads  130 . A second conductive film is formed in the bottom surface  112  of the substrate  110  and is patterned to form the plurality of connecting pads  131 . One end of each lead of the plurality of leads  130  extends along the side surface  113  to the top surface  111 , to couple with the sensor electrodes  120 . In the embodiment, the first conductive film and the second conductive film are patterned by yellow light etching or laser etching. 
         [0030]    At block  503 , a first insulating layer  140  is formed to cover the sensor electrodes  120  and a second insulating layer  160  is formed on the bottom surface  112 . The plurality of connecting pads  131  is thus exposed. 
         [0031]    At block  504 , a conductive layer  150  is formed on the first insulating layer  140 . In detail, a conductive material layer is deposited on the first insulating layer  140  and a plurality of openings  151  are defined to correspond to the plurality of sensor electrodes  120 . A size of each opening of the plurality of openings is larger than a size of each electrode of the plurality of sensor electrodes  120 . A gap (shown in  FIG. 3 ) D is defined between the opening  151  and sensor electrode  120 . In the embodiment, a width of the gap D is 0-30 micrometers. A width of each opening of the plurality of openings  151  is 80-260 micrometers. In the embodiment, the openings  151  are formed by yellow light etching or laser etching. 
         [0032]    At block  505 , a protection adhesive  170  is formed on the side surface  113  to cover the plurality of leads  130 . In the embodiment, the protection adhesive  170  is formed by spray or printing technology. 
         [0033]    At block  506 , a contact protection layer  190  is formed on the conductive layer  150 . 
         [0034]    At block  507 , the fingerprint identification controller  180  is assembled on the bottom surface  112  to couple with the plurality of connecting pads  131 . 
         [0035]    It is to be understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and changes may be in detail, especially in the matter of arrangement of parts within the principles of the embodiments, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.