Patent Publication Number: US-2018053806-A1

Title: Sensing device

Description:
FIELD OF THE INVENTION 
     The present invention relates to a sensing device, and in particular, to a sensing device capable of sensing a fingerprint of a user. 
     BACKGROUND OF THE INVENTION 
     In recent years, a fingerprint identification technology is applied to various electronic products, so that a user can input a fingerprint to an electronic product, the electronic product stores the fingerprint, and the user can input the fingerprint of the user by using a fingerprint identification module, to unlock an electronic product. Unlocking an electronic product by using a fingerprint identification technology is faster and more convenient than a previous unlocking manner in which a password is manually entered, and therefore, the former unlocking manner is preferred by users. Moreover, there is also an increasing requirement on sensing devices having a fingerprint identification function. 
     Referring to  FIG. 1 ,  FIG. 1  is a schematic structural diagram of a conventional sensing device. A conventional sensing device  1  includes a protective cover  10 , a transmitting electrode module  11 , a receiving electrode module  12 , and a substrate  13 . The receiving electrode module  12  includes a guard layer  121 , a receiving electrode layer  122 , an insulating plate  123 , and a conductor wire  124 . These components are sequentially the protective cover  10 , the guard layer  121 , the receiving electrode layer  122 , the insulating plate  123 , the substrate  13 , and the transmitting electrode module  11  from top to bottom. The conductor wire  124  is located on sides of the receiving electrode layer  122  and the insulating plate  123 . The protective cover  10  is disposed on the receiving electrode module  12  and exposes outside as a part of the sensing device  1 . The protective cover  10  can protect the receiving electrode module  12  from being damaged and be provided for touching of a finger of a user. The transmitting electrode module  11  is disposed on a lower surface of the substrate  13 , and is configured to generate a detection signal, so as to detect a surface of a finger touching the protective cover  10 . The detection signal is reflected by the surface of the finger on the protective cover  10  and converted into a reflection signal. 
     The receiving electrode module  12  is disposed between the protective cover  10  and the substrate  13 , and is configured to receive the reflection signal. In the receiving electrode module  12 , the insulating plate  123  is disposed on an upper surface of the substrate  13 , and can separate the receiving electrode layer  122  from the substrate  13 . The receiving electrode layer  122  is disposed on an upper surface of the insulating plate  123  and can receive the reflection signal. The conductor wire  124  is separately electrically connected to the receiving electrode layer  122  and the substrate  13 . The guard layer  121  covers the receiving electrode layer  122 , to protect the receiving electrode layer  122  from being damaged by an external force. The insulating plate  123  is made of a polyvinylidene fluoride (Polyvinylidene fluoride, PVDF) material. The guard layer  121  is made of an acryl material. The receiving electrode layer  122  is made of a metal conductive material or an indium tin oxide (Indium Tin Oxide, ITO). The metal conductive material includes an aluminum material, an aluminum alloy material, a bronze material, a bronze alloy material, a nickel material, a gold material, a platinum material, and the like. The substrate  13  is disposed between the receiving electrode module  12  and the transmitting electrode module  11 , and can obtain a surface imaging of a finger according to a reflection signal. The substrate  13  is thin-film transistor (Thin-Film Transistor, TFT) glass. 
     An operation principle of the structure of the foregoing conventional sensing device  1  is: When a user puts a finger on the protective cover  10 , the transmitting electrode module  11  generates a detection signal, and the detection signal is transmitted to the protective cover  10  in an ultrasonic form, to detect a surface of the finger touching the protective cover  10 . The detection signal is reflected by the surface of the finger on the protective cover  10 , and in this case, the detection signal is defined as a reflection signal. The reflection signal is transmitted to the receiving electrode layer  122  in an ultrasonic form, so that the receiving electrode layer  122  transmits the reflection signal to the substrate  13  by using the conductor wire  124 . Actually, the substrate  13  connects to a processor (which is not shown in the figure). When the substrate  13  receives the reflection signal, the processor can calculate the current strength of the surface of the finger according to the reflection signal, so as to obtain a surface imaging of the finger through calculation. 
     However, although the guard layer  121  can protect the receiving electrode layer  122 , the guard layer  121  lowers sensitivity of receiving a reflection signal by the receiving electrode layer  122 , thereby easily causing an error in fingerprint identification. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a sensing device whose sensitivity can be improved. 
     In a preferred embodiment, the present invention provides a sensing device, configured to retrieve a surface imaging of an object and including: a protective cover, a transmitting electrode module, a receiving electrode module, and a substrate. The protective cover is configured to be in contact with the object; the transmitting electrode module is configured to output a detection signal to the protective cover, to detect a surface of the object; The receiving electrode module is disposed under the protective cover and configured to receive a reflection signal reflected by the surface of the object; and The substrate is disposed under the receiving electrode module and configured to obtain the surface imaging of the object according to the reflection signal, where the receiving electrode module includes an insulating plate, a receiving electrode layer, and a conductive circuit layer. The insulating plate is disposed at the bottom of the receiving electrode module and configured to separate the receiving electrode module from the substrate or the transmitting electrode module; the receiving electrode layer is disposed on the insulating plate and configured to receive the reflection signal; and the conductive circuit layer covers the receiving electrode layer and separately electrically connects to the receiving electrode layer and the substrate, to establish an electrical connection between the receiving electrode layer and the substrate. 
     In a preferred embodiment, the present invention provides a sensing device, configured to retrieve a surface imaging of an object and including: a protective cover, a transmitting electrode module, a receiving electrode module, and a substrate. The protective cover is configured to be in contact with the object; the transmitting electrode module is configured to output a detection signal to the protective cover, to detect a surface of the object; the receiving electrode module is disposed under the protective cover and configured to receive a reflection signal reflected by the surface of the object; and the substrate is disposed under the receiving electrode module and configured to obtain the surface imaging of the object according to the reflection signal, where the receiving electrode module includes: an insulating plate and a conductive circuit layer. The insulating plate is disposed at the bottom of the receiving electrode module and configured to separate the receiving electrode module from the substrate or the transmitting electrode module; and the conductive circuit layer covers the insulating plate and electrically connects to the substrate, to receive the reflection signal and transmit the reflection signal to the substrate. 
     In short, in the sensing device in the present invention, a conductive circuit layer printed in a stepped shape takes place of a conductor wire and a guard layer in the conventional sensing device, so that the sensing device can be not provided with a guard layer with which sensitivity is lowered. In other words, sensitivity of the sensing device in the present invention can be improved. In addition, a preferred operation can be used: the conductive circuit layer printed in a stepped shape may be used to take place of a conductor wire, a guard layer, and a receiving electrode layer in a conventional sensing device, which not only can improve sensitivity, but also can reduce thickness of a sensing device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram of a conventional sensing device; 
         FIG. 2  is a schematic structural diagram of a sensing device of the present invention in a first preferred embodiment; and 
         FIG. 3  is a schematic structural diagram of a sensing device of the present invention in a second preferred embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides a sensing device, to solve a conventional technical problem. Referring to  FIG. 2 ,  FIG. 2  is a schematic structural diagram of a sensing device of the present invention in a first preferred embodiment. The sensing device  2  can retrieve a surface imaging of an object (which is not shown in the figure), and includes a protective cover  20 , a transmitting electrode module  21 , a receiving electrode module  22 , and a substrate  23 . The receiving electrode module  22  includes a receiving electrode layer  221 , an insulating plate  222 , and a conductive circuit layer  223 . These components are sequentially the protective cover  20 , the conductive circuit layer  223 , the receiving electrode layer  221 , the insulating plate  222 , the substrate  23 , and the transmitting electrode module  21  from top to bottom. The conductive circuit layer  223  covers the receiving electrode layer  221 , the insulating plate  222 , and a part of the substrate  23 . In the preferred embodiment, the object is a finger of a user. 
     The protective cover  20  is located at the top of the sensing device  2 , and exposes outside as a part of the sensing device  2 , and therefore can be in contact with an object. The transmitting electrode module  21  is disposed on a lower surface of the substrate  23  and is electrically connected to the substrate  23 , and configured to generate a detection signal, so as to detect a surface of an object touching the protective cover  20 . The detection signal is reflected by the surface of the object on the protective cover  20 . The reflected detection signal is defined as a reflection signal. The receiving electrode module  22  is disposed under the protective cover  20  and on the substrate  23 , and is configured to receive the reflection signal reflected by the surface of the object. The substrate  23  is disposed under the receiving electrode module  22  and on the transmitting electrode module  21 , and configured to obtain a surface imaging of the object according to the reflection signal. In the preferred embodiment, the substrate  23  is thin-film transistor (TFT) glass. 
     In the receiving electrode module  22 , the insulating plate  222  is disposed on an upper surface of the substrate  23 , and can separate the receiving electrode layer  221  from the substrate  23 . The receiving electrode layer  221  is disposed on an upper surface of the insulating plate  222 , and can receive the reflection signal. The conductive circuit layer  223  covers the receiving electrode layer  221  and a part of the substrate  23 , and is separately electrically connected to the receiving electrode layer  221  and the substrate  23 . The conductive circuit layer  223  has two functions: First, establishing an electrical connection between the receiving electrode layer  221  and the substrate  23 ; second, protecting the receiving electrode layer  221  from being damaged by an external force. In the preferred embodiment, the receiving electrode layer  221  is made of a metal conductive material or an indium tin oxide (ITO). The conductive circuit layer  223  is formed of a silver material printed on an upper surface of the receiving electrode layer  221  and the upper surface of the substrate  23 , so that the conductive circuit layer  223  covers the receiving electrode layer  221 , the insulating plate  222 , and a part of the substrate  23 . The conductive circuit layer  223  is presented in a stepped form. The insulating plate  222  is made of a polyvinylidene fluoride (PVDF) material. 
     An operation principle of detecting by the sensing device  2  the surface of the object on the protective cover  20  is the same as a conventional technical principle, and details are not described herein again. Through operation of the sensing device  2 , the surface imaging of the object can be obtained. There are two points needing to be noted that: First, in the sensing device  2  in the present invention, the conductive circuit layer  223  printed in a layer shape takes place of a conventional conductor wire and a guard layer; because the sensing device  2  is not provided with a guard layer, sensitivity of receiving the reflection signal by the receiving electrode layer  221  is not affected. In other words, sensitivity of the sensing device in the present invention can be improved. Second, in the preferred embodiment, the transmitting electrode module  21  is disposed on the lower surface of the substrate  23 , which is merely used as an example, but not a limitation. In another preferred embodiment, the transmitting electrode module may also be disposed on an upper surface of the substrate, that is, the transmitting electrode module is disposed between the receiving electrode layer and the substrate. In this case, the insulating plate separates the receiving electrode module from the transmitting electrode module. 
     In addition, the present invention further provides a second preferred embodiment different from the foregoing operations. Referring to  FIG. 3 ,  FIG. 3  is a schematic structural diagram of a sensing device of the present invention in a second preferred embodiment. The sensing device  3  includes a protective cover  30 , a transmitting electrode module  31 , a receiving electrode module  32 , and a substrate  33 . The receiving electrode module  32  includes an insulating plate  321  and a conductive circuit layer  322 . These components are sequentially the protective cover  30 , the conductive circuit layer  322 , the insulating plate  321 , the substrate  33 , and the transmitting electrode module  31  from top to bottom. The conductive circuit layer  322  covers the insulating plate  321  and a part of the substrate  33 . A difference between the sensing device  3  in the preferred embodiment and the first preferred embodiment lies in that, the receiving electrode layer  223  in the first preferred embodiment is removed, and the conductive circuit layer  322  takes place of the receiving electrode layer  223 . 
     It can be known from  FIG. 3  that, the insulating plate  321  is disposed at the bottom of the receiving electrode module  32 , and can separate the receiving electrode module  32  from the substrate  33 . The conductive circuit layer  322  is made of a silver material printed on an upper surface of the insulating plate  321  and a part of an upper surface of the substrate  33 , so that the conductive circuit layer  322  covers the insulating plate  321  and the part of substrate  33  and can be electrically connected to the substrate  33 . Compared with the first preferred embodiment, in the preferred embodiment, the conductive circuit layer  322  takes place of the receiving electrode layer  223 . Therefore, the receiving electrode module  32  in the preferred embodiment can have relatively small thickness and can be lighter. 
     It can be known from the above that, in the sensing device in the present invention, a conductive circuit layer printed in a layer shape takes place of a conductor wire and a guard layer in the conventional sensing device, so that the sensing device can be not provided with a guard layer with which sensitivity is lowered. In other words, sensitivity of the sensing device in the present invention can be improved. In a preferred operation, the conductive circuit layer printed in a stepped shape may be used to take place of a conductor wire, a guard layer, and a receiving electrode layer in a conventional sensing device, which not only can improve sensitivity, but also can reduce thickness of a sensing device. 
     The above descriptions are merely preferred embodiments of the present invention, and are not intended to limit the patent application scope of the present invention, and therefore, any equivalent change or modification made without departing from the spirits of the invention falls within the patent application scope of this specification.