Patent Publication Number: US-2016224817-A1

Title: Electronic device having fingerprint recognition function

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 201510048653.1 filed on Jan. 30, 2015, the contents of which are incorporated by reference herein. 
     FIELD 
     The subject matter herein generally relates to a method for patterning conductive materials by using light annealing technologies. 
     BACKGROUND 
     Fingerprint recognition technologies are utilized in various electronic devices, such as smart phones, tablet computers, personal digital assistants (PDA), and media players. For example, a smart phone may utilize at least one fingerprint sensor under a home screen key to sensing fingerprint. In addition, curved devices, such as smart watch, smart phone having curved outer housings, or other similar devices, have been developed. Curved devices may comprise outer housings permanently curved around one or more axes and may provide users with unique interfaces and user experiences. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
         FIG. 1  illustrates a diagrammatic view of an electronic device according to a first embodiment. 
         FIG. 2  illustrates a cross sectional view of the electronic device taken long line II-II of  FIG. 1 . 
         FIG. 3  illustrates a cross sectional view of the electronic device taken long line III-III of  FIG. 1 . 
         FIG. 4  illustrates a diagrammatic view of functional modules of the electronic device of  FIG. 1 . 
         FIG. 5  illustrates a diagrammatic view of an electronic device according to a second embodiment. 
         FIG. 6  illustrates a cross sectional view of the electronic device taken long line V-V of  FIG. 5 . 
       FIG. 7  illustrates a cross sectional view of the electronic device taken long line VI-VI of  FIG. 5 . 
         FIG. 8  illustrates a diagrammatic view of functional modules of the electronic device of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     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. The term “a plurality of”, when utilized, means “at least two”. 
     The present disclosure is described in relation to a method for forming electrode patterns on a substrate using light annealing technologies. In summary, a layer of conductive materials is formed on the substrate, and a portion of the conductive materials is annealed by an exposing manner. The layer of conductive materials after being extended includes an annealed first portion and an unannealed second portion. One of the annealed first portion and the unannealed second portion is removed from the substrate to form electrode patterns on the substrate. More details are provided below. 
       FIG. 1  illustrates a diagrammatic view of an electronic device  100  according to a first embodiment. The electronic device  100  can include a housing  10  and a cover  20  coupled with the housing  10  to define a receiving space to receive components of the electronic device  100 . In at least one embodiment, the cover  20  includes a transparent region  21  and a non-transparent region  22 . The transparent region  21  corresponds to a display area of the electronic device  100 . The cover  20  can be made of glasses. Therefore, the cover  20  can also be called “cover glass” or “protection glass”. 
     The electronic device  100  further includes a plurality of buttons. In at least one embodiment, the electronic device  100  at least includes a first button  11 , a second button  12 , and a third button  13 . The first button  11  and the second button  12  pass through and extend out of the housing  10 . The third button  13  passes through and extends out of the cover  20 . The first button  11  can be a power button of the electronic device  100 . The second button  12  can be a volume adjustment button for the electronic device  100 . The third button  13  can be a home screen button of the electronic device  100 . In at least one example, the cover  20  can define a through hole in the non-transparent region. Thus, the third button  13  can pass through the through hole, thereby extending out from the cover  20 . 
     The electronic device  100  further includes at least two fingerprint sensors respectively located under at least two of the plurality of buttons. For example, referring to  FIG. 2 , the electronic device  100  can include a first fingerprint sensor  30  located under the first button  11 . Referring  FIG. 3 , the electronic device can further include a second fingerprint sensor  40  located under the third button  13 . Each of the first and second fingerprint sensors  30  and  40  can be an optical fingerprint sensor, a heat induction fingerprint sensor, an ultrasonic fingerprint sensor, or a capacitance fingerprint sensor. Both the first fingerprint sensor  30  and the second fingerprint sensor  40  are ultrasonic fingerprint sensors. The at least two fingerprint sensors are configured to acquire fingerprint information from user when any of the buttons is touched by at least one finger of the user. 
     Further referring  FIG. 2 , the first fingerprint sensor  30  can include a substrate  32  and a pair of electrode layers comprising a first electrode layer  31  and a second electrode layer  33  respectively coupled at opposite surfaces of the substrate  32 . The substrate  32  can be a thin film transistor (TFT) substrate having a plurality of TFTs  34 . In other embodiments, the substrate  32  can also be a glass substrate, such as a chemically strengthened glass substrate. 
     The first electrode layer  31  can include a layer of piezoelectric materials and two layers of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be formed on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the first electrode layer  31 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the first electrode layer  31  can be attached on the surface of the substrate  32  by adhesive materials, such as liquid adhesive, double side adhesive, or optical adhesive (such as optical clear adhesive or optical clear resin). 
     The second electrode layer  33  is similar to the first electrode layer  31 . The second electrode layer  33  can include a layer of piezoelectric materials and two layers of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be formed on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the second electrode layer  33 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the second electrode layer  33  can serve as a signal transmission layer to produce ultrasonic waves when it is powered. When an external object touches or moves to the first fingerprint sensor  30 , the ultrasonic waves come to the external object and are reflected by the external object. The first electrode layer  31  can serve as a signal receiving layer to receive the ultrasonic waves reflected from the external object and to convert the ultrasonic waves into electric signals. The electric signals are transmitted to the TFTs  34  for analyzing, thereby realizing the fingerprint recognition function of the first fingerprint sensor  30 . 
     Further referring  FIG. 3 , the second fingerprint sensor  40  is similar to the first fingerprint sensor  30 . The second fingerprint sensor  40  includes a substrate  42  and a pair of electrode layers comprising a first electrode layer  41  and a second electrode layer  43  respectively coupled at opposite surfaces of the substrate  42 . The substrate  42  can be a thin film transistor (TFT) substrate having a plurality of TFTs  44 . In other embodiments, the substrate  42  can also be a glass substrate, such as a chemically strengthened glass substrate. 
     The first electrode layer  41  can include a layer of piezoelectric materials and two layer of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be formed on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the first electrode layer  41 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the first electrode layer  41  can be attached on the surface of the substrate  42  by adhesive materials, such as liquid adhesive, double side adhesive, or optical adhesive (such as optical clear adhesive or optical clear resin). 
     The second electrode layer  43  is similar to the first electrode layer  41  and it can include a layer of piezoelectric materials and two layer of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance. Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be formed on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the second electrode layer  43 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the second electrode layer  43  can serve as a signal transmission layer to produce ultrasonic waves when it is powered. When an external object touches or moves to the second fingerprint sensor  40 , the ultrasonic waves come to the external object and are reflected by the external object. The first electrode layer  41  can serve as a signal receiving layer to receive the ultrasonic waves reflected from the external object and to convert the ultrasonic waves into electric signals. The electric signals are transmitted to the TFTs  44  for analyzing, thereby realizing the fingerprint recognition function of the second fingerprint sensor  40 . 
     In other embodiments, the electronic device  100  can further include a third fingerprint sensor (not shown) located under the third button  13 . The third fingerprint sensor can have the same or similar structure with the first and second fingerprint sensors  30 ,  40 , details thereof are omitted. 
     As illustrated in  FIG. 4 , the electronic device  100  can further includes a processor  101  and a storage device  102  coupled to the processor  101 . The processor  101  is coupled to both the first fingerprint sensor  30  and the second fingerprint sensor  40 . In at least one embodiment, each of the first and second fingerprint sensors  30 ,  40  is associated with a predetermined function of the electronic device  100 . When one of the first and second fingerprint sensors  30 ,  40  acquires a fingerprint which matches one of at least one predetermined fingerprint stored in the storage device  102 , the processor  101  controls the electronic device  100  to perform the predetermined function associated with the one of the first and second fingerprint sensors  30 ,  40 . 
     In at least one embodiment, the first fingerprint sensor  30  can be associated with a first function of the electronic device  100  and the second fingerprint sensor  40  is associated with a second function of the electronic device  100 . The first function may be to power off the electronic device  100  and the second function may be to unlock the electronic device  100 . A first predetermined fingerprint and a second predetermined fingerprint may be pre-stored in the storage device  102 . When a fingerprint is acquired by the first fingerprint sensor  30 , the processor  101  compares the acquired fingerprint with the first predetermined fingerprint. If the acquired fingerprint matches the first predetermined fingerprint, the processor  101  automatically powers off the electronic device  100 . In the same manner, if the second fingerprint sensor  40  acquires a fingerprint that matches the second predetermined fingerprint, the processor  101  may unlock the electronic device  100 . Thus, some functions of the electronic device  100  can be quickly and automatically triggered when appropriated fingerprints are input. 
     As described above, besides the fingerprint sensor (second fingerprint sensor  40 ) installed under the home screen button (third button  13 ) of the electronic device  100 , the electronic device  100  further includes the other fingerprint sensor (first fingerprint sensor  30 ) installed under the power button (first button  11 ). Thus, when the home screen button malfunctions due to a large number of pressing operations applied thereon, the user can also input fingerprints using the other fingerprint sensor located under the power button to operate the electronic device  100 . 
       FIG. 5  illustrates a diagrammatic view of an electronic device  200  according to a second embodiment. In at least one embodiment, the electronic device  200  can be a curved device such as a curved smart phone, a smart car key, a smart watch, or other devices the like. In this embodiment, the curved device  200  is a smart watch for an example. 
     The electronic device  200  includes at least one curved region  210  and at least one button including at least a first button  220  and a second button  221  located within the curved region  210 . In at least one embodiment, the electronic device  200  further includes at least one fingerprint sensor installed under the curved region  210 . For example, a first fingerprint sensor  230  is located under the first button  220 . The first fingerprint sensor  230  can be an optical fingerprint sensor, a heat induction fingerprint sensor, an ultrasonic fingerprint sensor, or a capacitance fingerprint sensor. The first fingerprint sensor  230  is an ultrasonic fingerprint sensor. The first fingerprint sensor  230  is configured to acquire fingerprints from user when the first button  220  buttons is touched by at least one finger of the user, thereby controlling the electronic device  200  to execute corresponding functions according to the fingerprints acquired by the first fingerprint sensor  230 . 
     In at least one embodiment, the first button  230  and the second button  221  can be mechanical buttons protruding from the at least one curved region. In other embodiment, the first button  230  and the second button  221  can be virtual buttons defined by software programs. Thus, the first button  230  and the second button  221  can be marked by various identifiers (such as patterns, texts, or numbers) within the at least one curved region. In at least one embodiment, the curved region  210  refers to a part of the electronic device  200  having a curved shape (such as have a curved inner side surface and a curved outside surface). 
     As illustrated in  FIG. 6 , the first fingerprint sensor  230  includes a substrate  232  and a pair of electrode layers comprising a first electrode layer  231  and a second electrode layer  232  coupled at opposite sides of the substrate  230 . The substrate  232  can be a thin film transistor (TFT) substrate having a plurality of TFTs  234 . In other embodiments, the substrate  232  can also be a glass substrate, such as a chemically strengthened glass substrate. In this embodiment, in order to fit the curved region, the substrate  232  of the first fingerprint sensor  30  can be a flexible thin film substrate made of flexible materials, such as plastics or polymer transparent resin materials. The first electrode layer  231 , the substrate  232 , and the second electrode layer  233  each has the same shape with the curved region  210 . 
     The first electrode layer  231  can include a layer of piezoelectric materials and two layer of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be coated on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the first electrode layer  231 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the first electrode layer  231  can be attached on the surface of the substrate  232  by adhesive materials, such as liquid adhesive, double side adhesive, or optical adhesive (such as optical clear adhesive or optical clear resin). 
     The second electrode layer  233  is similar to the first electrode layer  231 . The second electrode layer  233  can include a layer of piezoelectric materials and two layers of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     In at least one embodiment, the second electrode layer  233  can serve as a signal transmission layer to produce ultrasonic waves when it is powered. When an external object touches or moves to the first fingerprint sensor  230 , the ultrasonic waves come to the external object and are reflected by the external object. The first electrode layer  231  can serve as a signal receiving layer to receive the ultrasonic waves reflected from the external object and to convert the ultrasonic waves into electric signals. The electric signals are transmitted to the TFTs  234  for analyzing, thereby realizing the fingerprint recognition function of the first fingerprint sensor  230 . 
     In other embodiments, the other fingerprint (not shown) can also be installed under the second button  221 . The other fingerprint sensor can have the same or similar structure with the first fingerprint sensors  230 , details thereof are omitted. 
     Further referring to  FIG. 5 , the electronic device  200  further includes a display  240 . The display  240  can be a curved display screen. Referring to  FIG. 7 , the electronic device  200  further includes a second fingerprint sensor  330  located under the display  240 . The second fingerprint sensor  330  is configured to acquire fingerprint from user when the display  240  is touched by any finger of the user. The second fingerprint sensor  330  can be an optical fingerprint sensor, a heat induction fingerprint sensor, an ultrasonic fingerprint sensor, or a capacitance fingerprint sensor. The second fingerprint sensor  330  is an ultrasonic fingerprint sensor. In order to fit the shape of the display  240 , the second fingerprint sensor  330  is curve shaped as well as the display  240 . The second fingerprint sensor  330  can be located corresponding to a virtual button displayed on the display  240  to acquire the fingerprint at the time when the virtual button is touched. 
     The second fingerprint sensor  330  includes a substrate  332  and a pair of electrode layers comprising a first electrode layer  331  and a second electrode layer  332  coupled at opposite sides of the substrate  330 . The substrate  332  can be a thin film transistor (TFT) substrate having a plurality of TFTs  334 . In other embodiments, the substrate  332  can also be a glass substrate, such as a chemically strengthened glass substrate. In this embodiment, in order to fit the curved region, the substrate  332  of the second fingerprint sensor  330  can be a flexible thin film substrate made of flexible materials, such as plastics or polymer transparent resin materials. The first electrode layer  331 , the substrate  332 , and the second electrode layer  333  each has the same shape with the curved display  240 , such as each has a curved inner side surface and a curved outside surface. 
     The first electrode layer  331  can include a layer of piezoelectric materials and two layer of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     The conductive materials can be coated on the opposite surfaces of the layer of piezoelectric materials by a vacuum sputtering method, an electroplate method, or a coating method, to form the first electrode layer  331 . A thickness of the conductive materials formed on the opposite surfaces of the layer of piezoelectric materials is about from 400 angstroms to 1000 angstroms. 
     In at least one embodiment, the first electrode layer  331  can be attached on the surface of the substrate  332  by adhesive materials, such as liquid adhesive, double side adhesive, or optical adhesive (such as optical clear adhesive or optical clear resin). 
     The second electrode layer  333  is similar to the first electrode layer  331 . The second electrode layer  333  can include a layer of piezoelectric materials and two layers of conductive materials respectively coated on opposite surfaces of the layer of piezoelectric materials. For example, the conductive materials can be metal materials having good conductive performance Some example of the metal materials include, but not limit to, argentums, aluminum, copper, nickel, or alloy thereof. In other embodiments, the conductive materials can be transparent conductive materials, such as indium tin oxide, zinc oxide, Poly(3,4-ethylenedioxythiophene), carbon nanotube, Ag nano wire, or graphene. The piezoelectric materials can be polyvinylidene fluoride. 
     In at least one embodiment, the second electrode layer  333  can serve as a signal transmission layer to produce ultrasonic waves when it is powered. When an external object touches or moves to the second fingerprint sensor  330 , the ultrasonic waves come to the external object and are reflected by the external object. The first electrode layer  331  can serve as a signal receiving layer to receive the ultrasonic waves reflected from the external object and to convert the ultrasonic waves into electric signals. The electric signals are transmitted to the TFTs  334  for analyzing, thereby realizing the fingerprint recognition function of the second fingerprint sensor  330 . 
     As illustrated in  FIG. 8 , the electronic device  200  can further includes a processor  201  and a storage device  202  coupled to the processor  201 . The processor  201  is coupled to both the first fingerprint sensor  230  and the second fingerprint sensor  330 . In at least one embodiment, each of the first and second fingerprint sensors  230 ,  330  is associated with a predetermined function of the electronic device  200 . When one of the first and second fingerprint sensors  230 ,  330  acquires a fingerprint which matches one of at least one predetermined fingerprint stored in the storage device  202 , the processor  201  controls the electronic device  200  to perform the predetermined function associated with the one of the first and second fingerprint sensors  230 ,  330 . 
     In at least one embodiment, the first fingerprint sensor  330  can be associated with a first function of the electronic device  200  and the second fingerprint sensor  330  is associated with a second function of the electronic device  200 . The first function may be to power off the electronic device  200  and the second function may be to unlock the electronic device  200 . A first predetermined fingerprint and a second predetermined fingerprint may be pre-stored in the storage device  202 . When a fingerprint is acquired by the first fingerprint sensor  330 , the processor  201  compares the acquired fingerprint with the first predetermined fingerprint. If the acquired fingerprint matches the first predetermined fingerprint, the processor  201  automatically powers off the electronic device  200 . In the same manner, if the second fingerprint sensor  330  acquires a fingerprint that matches the second predetermined fingerprint, the processor  201  may unlock the electronic device  200 . Thus, some functions of the electronic device  200  can be quickly and automatically triggered when appropriated fingerprints are input. 
     The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims.