Patent Publication Number: US-2021164270-A1

Title: Door handle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/JP2019/009771, filed on Mar. 11, 2019 and designating the U.S., which claims priority to Japanese Patent Application No. 2018-152848 filed on Aug. 15, 2018. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosures herein relate to a door handle. 
     2. Description of the Related Art 
     Door handles for opening and closing doors are attached to the doors of vehicles. In recent years, door handles allowing users to lock and unlock doors by moving the hands near the door handles are known. In such a door handle, a capacitance sensor configured to detect an operation by hand is provided. 
     A capacitance sensor provided in a door handle is configured to apply a voltage to electrodes disposed in the capacitance sensor and measure capacitances. Therefore, the door handle includes a power source for applying the voltage to the electrodes of the capacitance sensor and an electric circuit for controlling the application of the voltage. In order to drive the capacitance sensor and the electric circuit, power is supplied from a battery of a vehicle such as an automobile to the capacitance sensor and the electric circuit. However, as the power of the battery is limited, it is preferable to reduce the power consumed by the capacitance sensor and the electric circuit of the door handle. 
     RELATED-ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: Japanese Laid-Open Patent Publication No. 10-308148 
     Patent Document 2: WO2014/125577 
     SUMMARY OF THE INVENTION 
     It is desirable to provide a door handle equipped with a capacitance sensor that can be driven with low power consumption. 
     According to at least one embodiment, a door handle including a capacitance sensor configured to detect an operation body is provided. The capacitance sensor includes a substrate formed of an insulator and having a surface, at least one first sensor electrode disposed on the surface of the substrate, a plurality of second sensor electrodes disposed on the surface of the substrate, and a controller. The number of the plurality of second sensor electrodes is greater than the number of the at least one first sensor electrode. The controller applies a voltage to the plurality of second sensor electrodes and detects a coordinate position of the operation body, in a case where a capacitance between the operation body and the at least one first sensor electrode is greater than or equal to a predetermined value. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a diagram illustrating a door to which a door handle according to a first embodiment is attached; 
         FIG. 2  is a perspective view of the door handle according to the first embodiment; 
         FIG. 3  is a top view of the door handle according to the first embodiment; 
         FIG. 4  is a cross-sectional view of the door handle according to the first embodiment; 
         FIG. 5  is a diagram illustrating a capacitance sensor according to the first embodiment; 
         FIG. 6  is a diagram illustrating a configuration of a controller that controls the capacitance sensor according to the first embodiment; 
         FIG. 7  is a flowchart of a detection process by the capacitance sensor according to the first embodiment; 
         FIG. 8  is a diagram illustrating the detection process by the capacitance sensor according to the first embodiment; 
         FIG. 9  is a flowchart of calibration by the capacitance sensor according to the first embodiment; 
         FIG. 10  is a diagram (1) illustrating a variation of the capacitance sensor according to the first embodiment; 
         FIG. 11  is a diagram (2) illustrating a variation of the capacitance sensor according to the first embodiment; 
         FIG. 12  is a diagram (3) illustrating a variation of the capacitance sensor according to the first embodiment; 
         FIG. 13  is a diagram (4) illustrating a variation of the capacitance sensor according to the first embodiment; 
         FIG. 14  is a diagram (5) illustrating a variation of the capacitance sensor according to the first embodiment; 
         FIG. 15  is a diagram (6) illustrating a variation of the capacitance sensor according to the first embodiment; and 
         FIG. 16  is a diagram illustrating a capacitance sensor according to a second embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     According to at least one embodiment, a door handle equipped with a capacitance sensor can be driven at low power consumption. 
     In the following, embodiments will be described. The same members are denoted by the same reference numerals, and a description thereof will not be repeated. Further, in the present application, an X 1 -X 2  direction, a Y 1 -Y 2  direction, and a Z 1 -Z 2  direction are mutually perpendicular directions. Further, a plane including the X 1 -X 2  direction and the Y 1 -Y 2  direction is referred to as an XY-plane, a plane including the Y 1 -Y 2  direction and the Z 1 -Z 2  direction is referred to as a YZ-plane, and a plane including the Z 1 -Z 2  direction and the X 1 -X 2  direction is referred to as a ZX-plane. 
     First Embodiment 
     A door handle  10  according to a first embodiment is attached to a door  20  of a vehicle such as an automobile as illustrated in  FIG. 1 . As illustrated in  FIG. 2  through  FIG. 4 , the door handle  10  includes a door handle case  12  and a capacitance sensor  100  provided within the door handle case  12 . The door handle case  12  has a curved outer surface such that a user can readily grasp the door handle  10  with the hand.  FIG. 2  is a perspective view of the door handle  10 .  FIG. 3  is a top view of the door handle  10 .  FIG. 4  is a cross-sectional view of the door handle  10 . 
     Although not illustrated in  FIG. 4 , in the capacitance sensor  100 , a flat substrate  110  formed of an insulator and having an approximately rectangular shape is disposed, and electrodes for detection of capacitances are formed inside or on the surface of the substrate  110 . When the longitudinal direction of the door handle  10  is the X 1 -X 2  direction, the longitudinal direction of the substrate  110  of the capacitance sensor  100  provided within the door handle case  12  is also the X 1 -X 2  direction, and the surface of the substrate  110  of the capacitance sensor  100  is approximately parallel to the XY-plane. A through-hole  13  is provided through the door handle case  12  in order to pass wiring  113  connected to the capacitance sensor  100 . The wiring  113  is provided for electrically connecting the electrostatic sensor  100  to the exterior of the door handle  10 . Further, an integrated circuit  130  is mounted on the substrate  110 . The integrated circuit  130  serves as a controller configured to control the capacitance sensor  100 . 
     Next, the capacitance sensor  100  according to the present embodiment will be described. As illustrated in  FIG. 5 , the capacitance sensor  100  according to the present embodiment includes a first sensor electrode  150  and a plurality of second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j  formed on the surface of the substrate  110 . 
     The first sensor electrode  150  is formed on the Y 2  side of the substrate  110 , and is elongated in the X 1 -X 2  direction. The second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g ,  160   h,    160   i,  and  160   j  are formed on the Y 1  side of the substrate  110  relative to the first sensor electrode  150 , and are regularly arranged in a line at approximately equal intervals from the X 2  side to the X 1  side. In the capacitance sensor  100  according to the present embodiment, the first sensor electrode  150  detects whether a user&#39;s finger  200  approaches the capacitance sensor  100 , and the second sensor electrodes  160   a,    160   b,    160   c,    160   d ,  160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j  detect the position of the finger  200 . 
     Specifically, in the capacitance sensor  100  according to the present embodiment, the first sensor electrode  150  detects whether the finger  200  approaches the capacitance sensor  100 . When the first sensor electrode  150  detects that the finger  200  has approached the capacitance sensor  100 , a voltage is applied to the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h ,  160   i,  and  160   j  in order to detect the position of the finger  200 . The voltage is not applied to the second sensor electrodes  160   a,    160   b,    160   c,    160   d ,  160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j  until the first sensor electrode  150  detects that the finger  200  has approached the capacitance sensor  100 . In general, in a capacitance sensor, as the number of electrodes to which a voltage is applied decreases, the power consumed by an integrated circuit decreases. 
     In the present embodiment, a voltage is applied to the first sensor electrode only, until the finger approaches the capacitance sensor  100 , thus allowing power consumption to be reduced. In particular, when the door handle  10  is attached to a door of an automobile, there may be a case where the user&#39;s finger  200  does not approach the door handle  10  for a long time. Therefore, the door handle  10  that includes the capacitance sensor  100  according to the present embodiment is advantageous in reducing power consumption. 
     The capacitance sensor  100  according to the present embodiment may include a plurality of first sensor electrodes; however, the number of first sensor electrodes is preferably less than the number of second sensor electrodes. In other words, the number of second sensor electrodes is preferably greater than the number of first sensor electrodes. Further, one first sensor electrode is preferably used in terms of reducing power consumption. 
     In the capacitance sensor  100  according to the present embodiment, the first sensor electrode  150  and the second sensor electrodes  160   a,    160   b ,  160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i , and  160   j  are connected to the integrated circuit  130 . Note that  FIG. 5  does not depict wiring that connects the first sensor electrode  150  and the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g ,  160   h,    160   i,  and  160   j  to the integrated circuit  130 . 
     Specifically, as illustrated in  FIG. 6 , the integrated circuit  130  includes a switch  131  that is connected to each of the first sensor electrode  150  and the second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j.  By closing the switch  131 , a predetermined voltage Vdd can be applied to the first sensor electrode  150  and the second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j.  Accordingly, the potential of each of the first sensor electrode  150  and the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g ,  160   h,    160   i,  and  160   j  can be detected. Then, the detected potential is amplified by an amplifier  132 , and an analog signal is converted to a digital signal by an analog-to-digital converter (ADC)  133 . Based on the digital signal converted as described above, an arithmetic unit  134  can calculate the capacitance between the finger  200  and each of the sensor electrodes  150 ,  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j.  Information of the calculated capacitance between the finger  200  and each of the sensor electrodes  150 ,  160   a,    160   b ,  160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j  is transmitted to a sensor control unit  135 . The sensor control unit  135  includes a storage  136  that stores various information. 
     As used herein, the finger  200  may be referred to as an “operation body” because an operation is performed by the finger  200 . 
     (Detection Process by Capacitance Sensor) 
     Next, a process for detecting the position of the finger by the capacitance sensor  100  according to the present embodiment will be described. 
     First, in step  102  (S 102 ), a predetermined voltage Vdd is applied to the first sensor electrode  150  as controlled by the integrated circuit  130 . At this time, no voltage is applied to the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j.    
     Next, in step  104  (S 104 ), while the predetermined voltage Vdd is being applied to the first sensor electrode  150 , the capacitance is measured at the first sensor electrode  150 , and it is determined whether the measured capacitance is greater than or equal to a predetermined value. If the finger  200  approaches the capacitance sensor  100 , the capacitance between the finger  200  and the first sensor electrode  150  increases. Therefore, if the capacitance measured at the first sensor electrode  150  is greater than or equal to the predetermined value, it is determined that the user&#39;s finger  200  has approached the capacitance sensor  100 . Accordingly, if it is determined that the capacitance measured at the first sensor electrode  150  is greater than or equal to the predetermined value, the process proceeds to step  106 . Conversely, if it is determined that the capacitance measured at the first sensor electrode  150  is less than the predetermined value, the step  104  is repeated. 
     Next, in step  106  (S 106 ), the predetermined voltage Vdd is applied to the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j,  and capacitances are measured at the second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j.  At this time, a predetermined bias voltage may be applied to the first sensor electrode  150  such that the first sensor electrode  150  functions as a guard voltage that minimizes the influence of noise. 
     Next, in step  108  (S 108 ), the position of the finger  200  is detected based on the capacitances measured at the second sensor electrodes  160   a,    160   b ,  160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j  in step  106 . Specifically, if the user&#39;s finger  200  approaches the capacitance sensor  100 , capacitances as indicated in  FIG. 8  are measured at the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j.  The second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g ,  160   h,    160   i,  and  160   j  are arranged at equal intervals in the X-axis direction. Therefore, the X-coordinate position of the second sensor electrode  160   a  is Xo, the X-coordinate position of the second sensor electrode  160   b  is X 1 , the X-coordinate position of the second sensor electrode  160   c  is X 2 , the X-coordinate position of the second sensor electrode  160   d  is X 3 , the X-coordinate position of the second sensor electrode  160   e  is X 4 , the X-coordinate position of the second sensor electrode  160   f  is X 5 , the X-coordinate position of the second sensor electrode  160   g  is X 6  the X-coordinate position of the second sensor electrode  160   h  is X 7 , the X-coordinate position of the second sensor electrode  160   i  is X 8 , and the X-coordinate position of the second sensor electrode  160   j  is X 9 . 
     The capacitance is inversely proportional to the distance. Therefore, among the second sensor electrodes, a second sensor electrode having the highest capacitance value is located closest to the finger  200 , and the X-coordinate position of the second sensor electrode having the highest capacitance value corresponds to the X-coordinate position of the finger  200 . Accordingly, in the example illustrated in  FIG. 8 , the capacitance value of the second sensor electrode  160   d  is the highest, and thus, the X-coordinate position “X 3 ” of the second sensor electrode  160   d  corresponds to the X-coordinate position of the finger  200 . Further, in the example illustrated in  FIG. 8 , the second sensor electrode  160   e  has the next highest capacitance value. Therefore, it may be considered that the X-coordinate position of the finger  200  is between the X-coordinate position “X 3 ” of the second sensor electrode  160   d  and the X-coordinate position “X 4 ” of the second sensor electrode  160   e.    
     (Calibration) 
     Next, in-use calibration of the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j  of the electrostatic sensor  100  according to the present embodiment will be described with reference to  FIG. 9 . In the capacitance sensor  100  according to the present embodiment, the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h ,  160   i,  and  160   j  are not driven until the first sensor electrode  150  detects that the user&#39;s finger  200  has approached the capacitance sensor  10 . Therefore, in the case of a long time until start of measurements using the second sensor electrodes  160   a,    160   b,    160   c ,  160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j,  values measured from respective electrodes might deviate. For this reason, in the present embodiment, while there is no detection of approach of the finger  200  by the first sensor electrode  150  in the repeated steps  102  and  104  of  FIG. 7 , the predetermined voltage Vdd is applied at regular intervals to the second sensor electrodes  160   a,    160   b,    160   c,    160   d ,  160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j,  and calibration is performed such that capacitance values to be measured at the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g ,  160   h,    160   i,  and  160   j  are consistent. While the approach of the finger  200  is not being detected by the first sensor electrode  150 , the finger  200  is not located in the vicinity of the capacitance sensor  100 , that is, no object affecting capacitance is present in the vicinity of the capacitance sensor  100 . Accordingly, it is preferable to perform in-use calibration during this time. 
     Specifically, as illustrated in  FIG. 9 , first, in step  202  (S 202 ), the predetermined voltage Vdd is applied to the second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j,  and capacitance values are measured at the second sensor electrodes  160   a,    160   b,    160   c,    160   d ,  160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j.    
     Next, in step  204  (S 204 ), the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e ,  160   f,    160   g,    160   h,    160   i,  and  160   j  are calibrated based on the capacitance values measured at the second sensor electrodes  160   a,    160   b,    160   c,    160   d ,  160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j  in step  202 . 
     (Variations) 
     In the following, variations of the capacitance sensor according to the first embodiment will be described. Note that wiring that connects first sensor electrodes and second sensor electrodes to an integrated circuit is not depicted in the drawings. 
     In a capacitance sensor as illustrated in  FIG. 10 , a first sensor electrode  150  may be formed on the Y 2  side of second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j,  and a first sensor electrode  151  may be formed on the Y 1  side of the second sensor electrodes  160   a ,  160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h,    160   i,  and  160   j.  Further, the longitudinal direction of each of the first sensor electrode  150  and the first sensor electrode  151  is the X 1 -X 2  direction. With this configuration, the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h ,  160   i,  and  160   j  may be arranged in the X 1 -X 2  direction between the first sensor electrode  150  and the first sensor electrode  151 . Accordingly, by disposing the first sensor electrodes  150  and  151 , the finger  200  approaching not only from the Y 2  side but also from the Y 1  side can be detected. As a result, the detection accuracy of the capacitance sensor can be improved. Further, when capacitance values are measured at the second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h ,  160   i,  and  160   j,  a predetermined bias voltage may be applied to the first sensor electrodes  150  and  151  such that the first sensor electrodes  150  and  151  function as guard voltages that minimize the influence of noise. 
     Further, as illustrated in  FIG. 11 , the first sensor electrode  150  illustrated in  FIG. 5  may be divided into three first sensor electrodes  150   a ,  150   b,  and  150   c.    
     Further, as illustrated in  FIG. 12 , the first sensor electrode  150  illustrated in  FIG. 10  may be divided into two first sensor electrodes  150   d  and  150   e,  and the first sensor electrode  151  illustrated in  FIG. 10  may be divided into two first sensor electrodes  151   d  and  151   e.    
     Further, as illustrated in  FIG. 13 , an electrode  152  may be divided into a plurality of electrodes  152   a  that are connected by wiring  152   b  in the X 1 -X 2  direction. 
     Further, as illustrated in  FIG. 14 , a first sensor electrode  150 , whose longitudinal direction is the X 1 -X 2  direction, may be formed at the center in the Y 1 -Y 2  direction of the substrate  110 , second sensor electrodes  161   a,    161   b,    161   c ,  161   d,    161   e,    161   f,    161   g,    161   h,    161   i,  and  161   j  may be arranged on the Y 1  side of the first sensor electrode  150  in the X 1 -X 2  direction, and second sensor electrodes  162   a,    162   b,    162   c,    162   d,    162   e ,  162   f,    162   g,    162   h,    162   i,  and  162   j  may be arranged on the Y 2  side of the first sensor electrode  150  in the X 1 -X 2  direction. In this case, the position in the Y-axis direction of the finger  200  can also be detected by the second sensor electrodes  161   a  through  161   j  and the second sensor electrodes  162   a  through  162   j.    
     Further, as illustrated in  FIG. 15 , the first sensor electrode  150 , whose longitudinal direction is the X 1 -X 2  direction, may be formed at the center in the Y 1 -Y 2  direction of the substrate  110 , a second sensor electrode  163 , whose longitudinal direction is the X 1 -X 2  direction, may be formed on the Y 1  side of the first sensor electrode  150 , and a second sensor electrode  164 , whose longitudinal direction is the X 1 -X 2  direction, may be formed on the Y 2  side of the first sensor electrode  150 . In this case, although the sensor electrodes are driven in a different manner to that described above, the position in the Y-axis direction of the finger  200  can also be detected by the second sensor electrode  163 , the second sensor electrode  164 , and the first sensor electrode  150 . 
     Second Embodiment 
     Next, a second embodiment will be described. In the second embodiment, as illustrated in  FIG. 16 , a plurality of second sensor electrodes  160   a,    160   b,    160   c,    160   d,    160   e,    160   f,    160   g,    160   h ,  160   i,  and  160   j  may be surrounded by a first sensor electrode  250 . By forming the first sensor electrode  250  as described above, the first sensor electrode  250  can effectively function as a guard voltage that minimizes the influence of noise. 
     Other configurations of the second embodiment are the same as those of the first embodiment. 
     Although specific embodiments have been described above, the present invention is not limited to the above-described embodiments. Variations and modifications may be made to the described subject matter without departing from the scope of the invention as set forth in the accompanying claims.