Abstract:
There is provided a wireless switch including: an energy harvesting unit generating a first signal and a second signal when a first button is pressed and when the first button is released, respectively; a measuring unit measuring a period of time from a time at which the first signal is generated to a time at which the second signal is generated; and a wireless signal transmitting unit transmitting a control signal depending on the period of time measured by the measuring unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priorities and benefits of Korean Patent Application Nos. 10-2014-0088607 filed on Jul. 14, 2014 and 10-2015-0056484 filed on Apr. 22, 2015, with the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a wireless switch including an energy harvesting unit. 
     Generally, a wireless lighting control system includes a power module, a lighting unit in which a communications module is embedded, a wireless lighting controller, a network device connecting the lighting unit and the wireless lighting controller to each other, an illumination sensor, and the like. 
     However, a current wireless lighting control system requires a separate wireless lighting controller and a network device. Therefore, it is difficult to use current wireless lighting control systems in environments such as domestic dwellings due to relatively complicated structures and high manufacturing costs thereof, depending on system configurations. 
     SUMMARY 
     An aspect of the present disclosure may provide a wireless switch including an energy harvesting unit. 
     According to an aspect of the present disclosure, a wireless switch may include: an energy harvesting unit generating a first signal and a second signal when a first button is pressed and when the first button is released, respectively; a measuring unit measuring a period of time from a time at which the first signal is generated to a time at which the second signal is generated; and a wireless signal transmitting unit transmitting a control signal depending on the period of time measured by the measuring unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a plan view of a wireless switch according to an exemplary embodiment in the present disclosure; 
         FIG. 2  is a view schematically illustrating a configuration of the wireless switch according to an exemplary embodiment in the present disclosure; 
         FIG. 3  is a partially cut-away plan view of the wireless switch illustrated in  FIG. 1  according to an exemplary embodiment in the present disclosure; 
         FIG. 4  is a cross-sectional view of an energy harvesting unit according to an exemplary embodiment in the present disclosure; 
         FIGS. 5A and 5B  are cross-sectional views illustrating an operational state of the energy harvesting unit according to a first exemplary embodiment in the present disclosure; 
         FIGS. 6A and 6B  are cross-sectional views illustrating an operational state of the energy harvesting unit according to a second exemplary embodiment in the present disclosure; 
         FIGS. 7A and 7B  are cross-sectional views illustrating an operational state of the energy harvesting unit according to a third exemplary embodiment in the present disclosure; 
         FIG. 8  is a view illustrating a signal conversion of a wireless switch according to an exemplary embodiment in the present disclosure; 
         FIG. 9  is a view illustrating configurations of a wireless switch and a lighting device using the same according to an exemplary embodiment in the present disclosure; 
         FIG. 10  is a view illustrating a configuration of the wireless switch illustrated in  FIG. 9 ; and 
         FIG. 11  is a view illustrating a configuration of a remote device illustrated in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
     The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. 
       FIG. 1  is a plan view of a wireless switch according to an exemplary embodiment in the present disclosure; and  FIG. 2  is a view schematically illustrating a configuration of the wireless switch according to an exemplary embodiment in the present disclosure. 
     Referring to  FIGS. 1 and 2 , the wireless switch according to the exemplary embodiment may include energy harvesting units  100 ,  200 , and  300 , a rectifier  400 , a capacitor  500 , a converter  600 , and a wireless signal transmitting module  700 . 
     Energy generated in the energy harvesting units  100 ,  200 , and  300  may pass through the rectifier  400 , be stored in the capacitor  500 , converted to a stable voltage by the converter  600 , and may be transmitted to the wireless signal transmitting unit  700 . 
     The wireless signal transmitting unit  700  may generate a radio frequency communications signal depending on an input signal. The RF communications signal may be transmitted to an RF receiving module of an external electronic device. 
     The external electronic device may be a lighting device such as a light emitting diode (LED) lamp, or the like. 
     That is, the wireless switch according to an exemplary embodiment may use the energy generated in the energy harvesting units  100 ,  200 , and  300  as driving power of the wireless signal transmitting unit  700  to transmit turn-on and turn-off signals to the external electronic device. 
     In addition, the wireless switch according to an exemplary embodiment may transmit a dimming signal as well as the turn-on and turn-off signals to the external electronic device. This will be described below with reference to  FIG. 8 . 
     Therefore, a wireless control system may be simply built without using a mechanically complicated component in order to connect a switch to a lighting device, or the like, in a home. 
     Next, a configuration of the energy harvesting unit  100  generating energy used as driving power of the wireless signal transmitting unit  700 , according to a first exemplary embodiment, will be described with reference to  FIGS. 3 through 5B . 
       FIG. 3  is a partially cut-away plan view of the wireless switch illustrated in  FIG. 1 ;  FIG. 4  is a schematic cross-sectional view illustrating the energy harvesting unit and turn-on and turn-off buttons according to the exemplary embodiment; and  FIGS. 5A and 5B  are cross-sectional views illustrating a process of generating energy in the energy harvesting unit, according to the first exemplary embodiment. 
     First, referring to  FIGS. 3 and 4 , the energy harvesting unit  100  according to the first exemplary embodiment may include a thin film member  110 , a support member  120  supporting the thin film member  110 , a piezoelectric member  130  provided on the thin film member  110 , first and second upper electrodes  141  and  143  provided on one surface of the piezoelectric member  130 , and a common electrode  150  provided on the other surface of the piezoelectric member  130 . 
     As illustrated in  FIG. 4 , the energy harvesting unit  100  according to the first exemplary embodiment may be provided with one piezoelectric member  130  and two upper electrodes  141  and  143 . 
     In addition, a turn-on button  160  and a turn-off button  170  may be disposed in positions corresponding to one side and the other side of the thin film member  110 , respectively, in relation to the support member  120 . 
     The thin film member  110  may have a plate shape having elasticity, and may be supported by the support member  120 . 
     The support member  120  may be disposed in a position corresponding to a central portion of the thin film member  110  below the thin film member  110  to support the thin film member  110 . Therefore, in a case in which external force is applied to both sides of the thin film member  110  in relation to the support member  120 , displacement may be re-generated in portions of the thin film member  110  to which external force is applied. 
     The piezoelectric member  130  may be provided on the thin film member  110 . Therefore, when displacement is generated in the thin film member  110 , displacement may also be generated in the piezoelectric member  130 , and thus, a piezoelectric effect, in which a potential difference appears, may occur. 
     For example, when displacement is generated in the thin film member  110 , displacement may also be generated in the piezoelectric member  130  provided on the thin film member  110 , and electrical polarization may be generated in the piezoelectric member  130 . Therefore, a voltage may be generated in the first upper electrode  141  or the second upper electrode  143  provided on one surface of the piezoelectric member  130 , and an output current generated from the voltage may be used as the driving power of the wireless signal transmitting unit  700 . 
     The piezoelectric member  130  may be formed of lead zirconate titanate, barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ), lithium niobate (LiNbO 3 ), silicon dioxide (SiO 2 ), or the like. 
     The common electrode  150  may be provided in order to generate a potential difference, and be provided on the other surface of the piezoelectric member  130  to correspond to the first and second upper electrodes  141  and  143 . 
     As illustrated in  FIG. 4 , the common electrode  150  may be disposed over the entirety of the other surface of the piezoelectric member  130 . Alternatively, the common electrode  150  may be patterned and formed on portions of the other surface of the piezoelectric member  130  corresponding to the first and second upper electrodes  141  and  143 . 
     The first and second upper electrodes  141  and  143  may be disposed on one surface of the piezoelectric member  130  to be spaced apart from each other. 
     For example, the first and second upper electrodes  141  and  143  may be disposed on one side and the other side of the piezoelectric member  130 , respectively, in relation to the support member  120 . 
     Next, a process of generating energy in the energy harvesting unit  100  according to the first exemplary embodiment will be described with reference to  FIGS. 5A and 5B . 
     First, as illustrated in  FIG. 5A , when a user presses the turn-on button  160 , external force may be applied to one side of the thin film member  110  corresponding to the turn-on button  160 , and displacement may be generated on one side of the thin film member  110 . 
     When displacement is generated on one side of the thin film member  110  in relation to the support member  120 , displacement may also be generated on one side of the piezoelectric member  130 . As a result, a voltage may be generated in the first upper electrode  141  disposed on one side of the piezoelectric member  130 . 
     Next, as illustrated in  FIG. 5B , when a user presses the turn-off button  170 , external force may be applied to the other side of the thin film member  110  corresponding to the turn-off button  170 , and displacement may be generated on the other side of the thin film member  110 . 
     When displacement is generated on the other side of the thin film member  110  in relation to the support member  120 , displacement may also be generated on the other side of the piezoelectric member  130 . As a result, a voltage may be generated in the second upper electrode  143  disposed on the other side of the piezoelectric member  130 . 
     The voltages generated in the first and second upper electrodes  141  and  143  may be used as the driving power of the wireless signal transmitting unit  700 , and the wireless signal transmitting unit  700  may transmit the RF communications signals to the external electronic device depending on inputs of the turn-on button  160  and the turn-off button  170 . 
     Here, in a case in which the voltage is generated in the first upper electrode  141  depending on the input of the turn-on button  160 , the wireless signal transmitting unit  700  may transmit the RF communications signal (here, a turn-on signal or a positive (+) dimming signal) to the external electronic device. 
     In addition, in a case in which the voltage is generated in the second upper electrode  143  depending on the input of the turn-off button  170 , the wireless signal transmitting unit  700  may transmit the RF communications signal (here, a turn-off signal or a negative (−) dimming signal) to the external electronic device. 
       FIGS. 6A and 6B  are schematic cross-sectional views illustrating a process of generating energy in the energy harvesting unit  200  according to a second exemplary embodiment in the present disclosure. 
     Referring to  FIGS. 6A and 6B , the energy harvesting unit  200  according to the second exemplary embodiment may include a thin film member  210 , first and second support members  221  and  223  supporting the thin film member  210 , a piezoelectric member  230  provided on the thin film member  210 , an upper electrode  240  provided on one surface of the piezoelectric member  230 , and a lower electrode  250  provided on the other surface of the piezoelectric member  230 . 
     The energy harvesting unit  200  according to the second exemplary embodiment may be provided with one piezoelectric member  230 , one upper electrode  240 , and one lower electrode  250 . 
     In addition, the turn-on button  160  may be disposed in a position corresponding to a portion of the thin film member  210  positioned between the first and second support members  221  and  223 , and the turn-off button  170  may be disposed in a position corresponding to one side or the other side of the thin film member  210  in relation to the first and second support members  221  and  223 . 
     First, as illustrated in  FIG. 6A , since the turn-on button  160  is disposed in a position corresponding to a central portion of the thin film member  210 , when a user presses the turn-on button  160 , external force may be applied to the central portion of the thin film member  210 , such that the thin film member  210  may be bent in a ‘U’ shape. 
     A central portion of the piezoelectric member  230  may also be bent in a ‘U’ shape, depending on displacement of the thin film member  210 . As a result, voltage may be generated in the upper electrode  240  disposed on one surface of the piezoelectric member  230 . 
     Next, as illustrated in  FIG. 6B , since the turn-off button  170  is disposed in a position corresponding to either one side or the other side of the thin film member  210  in relation to the first and second support members  221  and  223 , when a user presses the turn-off button  170 , external force may be applied to one side or the other side of the thin film member  210  corresponding to the turn-off button  170 , such that displacement may be generated on one side or the other side of the thin film member  210 . 
     In this case, the thin film member  210  may be bent in a ‘∩’ shape. 
     The piezoelectric member  230  may also be bent in a ‘∩’ shape depending on displacement of the thin film member  210 . As a result, a voltage may be generated in the upper electrode  240  disposed on one surface of the piezoelectric member  230 . 
     Here, shapes in which the thin film member  210  is bent may be different from each other, depending on the inputs of the turn-on button  160  and the turn-off button  170 . In detail, a direction in which the thin film member  210  is bent when the turn-on button  160  is input and a direction in which the thin film member  210  is bent when the turn-off button is input may be opposite to each other. 
     Therefore, polarities of the voltages in the upper electrode  240  may be opposite to each other, and the wireless signal transmitting unit  700  may distinguish a turn-on signal and a turn-off signal from each other, depending on the polarities of the voltages and transmit an RF communications signal to an external electronic device. 
       FIGS. 7A and 7B  are schematic cross-sectional views illustrating a process of generating energy in the energy harvesting unit  300  according to a third exemplary embodiment in the present disclosure. 
     Referring to  FIGS. 7A and 7B , the energy harvesting unit  300  according to the third exemplary embodiment may be driven in the same scheme as that of the energy harvesting unit  100 , according to the first exemplary embodiment, except that it includes two piezoelectric members, two upper electrodes, and two lower electrodes. 
     The energy harvesting unit  300  according to the third exemplary embodiment may include a thin film member  310 , a support member  320  supporting a central portion of the thin film member  310  below the thin film member  310 , first and second piezoelectric members  331  and  333  provided on the thin film member  310 , first and second upper electrodes  341  and  343  provided on one surfaces of the first and second piezoelectric members  331  and  333 , respectively, and first and second lower electrodes  351  and  353  provided on the other surfaces of the first and second piezoelectric members  331  and  333 , respectively. 
     The first and second piezoelectric members  331  and  333  may be disposed on the thin film member  310  to be spaced apart from each other, and displacement may be generated therein according to displacement generated on one side and the other side of the thin film member  310 . 
       FIG. 8  is a schematic view illustrating a method of setting a magnitude of an RF communications signal in a wireless switch according to an exemplary embodiment in the present disclosure. 
     First, in a case in which a user presses the turn-on button  160 , voltages may be generated by displacement of the piezoelectric members  130 ,  230 ,  331  and  333 , and in a case in which a user removes force being applied to the turn-on button  160 , displacement may be re-generated in the piezoelectric members  130 ,  230 ,  331 , and  333  by elastic force of the thin film members  110 ,  210 , and  310 . 
     Therefore, in the energy harvesting units  100 ,  200 , and  300  according to exemplary embodiments, when a user presses the turn-on button  160 , the voltage may be generated, and even when a user removes the force being applied to the turn-on button  160 , the voltage may be generated. 
     That is, in the energy harvesting units  100 ,  200 , and  300 , two output pulses may be created by the input of the turn-on button. In this case, a pulse width Td between the two output pulses may be measured, and a magnitude of an RF communications signal transmitted by the wireless signal transmitting unit  700  may be changed depending on the measured pulse width Td. 
     The pulse width Td may be in proportion to a time for which a user presses the turn-on button  160 , and the magnitude of the RF communications signal to be transmitted may be changed depending on the time for which a user presses the turn-on button  160 . 
     That is, the wireless signal transmitting unit may transmit the RF communications signal by adjusting the magnitude thereof to transmit a dimming signal to an external electronic device such as a lighting device. 
     Therefore, illumination may be changed by an external electronic device such as a lighting device, depending on the magnitude of the received RF communications signal. 
     An application example of the wireless switch will be described with reference to  FIG. 9 . 
     The wireless switch  10  according to the present exemplary embodiment may control a remote device  20 . For example, the wireless switch  10  may control the remote device  20  disposed in a position in which a user may directly operate the remote device  20 , such as on a ceiling, or the like. For example, the wireless switch  10  may control a lighting device including a plurality of light sources  28 . However, the remote device that may be controlled by the wireless switch  10  is not limited to the lighting device. For example, the wireless switch  10  may control an air conditioner disposed on the ceiling. Alternatively, the wireless switch  10  may control a projector disposed on the ceiling. 
     The wireless switch  10  according to the present exemplary embodiment may include a plurality of buttons  160  and  170 . For example, the wireless switch  10  may include a first button  160  configured to generate first and second signals and a second button  170  configured to generate a third signal. 
     The first button  160  may generate a signal for operating a control unit of the remote device  20 . For example, the first signal of the first button  160  may allow the remote device  10  to perform a specific function. Alternatively, the second signal of the first button  160  may allow the remote device  10  to stop a specific function. 
     The second button  170  may generate a signal for controlling a power supply unit of the remote device  20 . For example, the third signal of the second button  170  may allow the remote device  10  to stop all functions. 
     A configuration of the wireless switch will be described with reference to  FIG. 10 . 
     The wireless switch  10  according to the present exemplary embodiment may include energy harvesting units for respective buttons. For example, the wireless switch  10  may include a first energy harvesting unit  100  for the first button  160  and a second energy harvesting unit  200  for the second button  170 . 
     The energy harvesting units  100  and  200  may include components converting piezoelectric energy generated by the buttons  160  and  170  into electrical signals. The configurations of the first energy harvesting unit  100  and the second energy harvesting unit  200  may be substantially the same as or similar to each other. For example, the first energy harvesting unit  100  and the second energy harvesting unit  200  may include rectifiers  410  and  420 , capacitors  510  and  520 , and converters  610  and  620 , respectively. The above-mentioned components may convert energy generated by the energy harvesting units  100  and  200  by manipulation of the buttons  160  and  170  into electrical signals. Alternatively, the first energy harvesting unit  100  and the second energy harvesting unit  200  may include first and second wireless signal transmitting units  710  and  720 , respectively. The wireless signal transmitting units  710  and  720  may convert the electrical signals generated by the energy harvesting units  100  and  200  into wireless signals appropriate for controlling the remote device  20 . 
     The first energy harvesting unit  100  and the second energy harvesting unit  200  may be configured to generate different wireless signals. For example, the first energy harvesting unit  100  and the second energy harvesting unit  200  may have different sizes. For example, a piezoelectric member of the first energy harvesting unit  100  may be smaller or larger than a piezoelectric member of the second energy harvesting unit  200 . Alternatively, the first rectifier  410  and the second rectifier  420  may be configured to rectify different types of current. Alternatively, capacitance of the first capacitor  510  and capacitance of the second capacitor  520  may be different from each other. 
     The wireless switch  10  configured as described above may transmit different wireless signals from the first energy harvesting unit  100  and the second energy harvesting unit  200  to control the remote device  20 . 
     Main components of the remote device will be described with reference to  FIG. 11 . 
     The remote device  20  may include a wireless signal receiving unit  22 , a control unit  24 , and a power supply unit  26 . However, the remote device  20  is not limited to including the above-mentioned components. For example, the remote device  20  may further include a component capable of performing a specific function, such as a light source  28 . 
     The wireless signal receiving unit  22  may be configured to receive the wireless signals transmitted by the wireless switch  10 . For example, the wireless signal receiving unit  22  may be configured to transmit and receive frequencies within the same band as that of the wireless signal transmitting units  710  and  720  of the wireless switch  10 . The wireless signal receiving unit  22  may convert the wireless signals from the wireless signal transmitting unit  710  and  720  into set electrical signals. For example, the wireless signal receiving unit  22  may convert a wireless signal from the first wireless signal transmitting unit  710  into a first signal or a second signal. Alternatively, the wireless signal receiving unit  22  may convert a wireless signal from the second wireless signal transmitting unit  720  into a third signal. The wireless signal receiving unit  22  configured as described above may be connected to the control unit  24 . 
     The control unit  24  may be operated depending on signals transmitted from the wireless signal receiving unit  22 . For example, when the control unit  24  receives the first signal from the wireless signal receiving unit  22 , the control unit  24  may generate a control signal so that the light source  28  is turned on. In addition, when the control unit  24  receives the first signal from the wireless signal receiving unit  22 , the control unit  24  may generate a control signal so that illumination of the turned-on light source  28  is gradually increased. Alternatively, when the control unit  24  receives the second signal from the wireless signal receiving unit  22 , the control unit  24  may generate a control signal so that illumination of the turned-on light source  28  is maintained in a current state. Alternatively, when the control unit  24  receives the third signal from the wireless signal receiving unit  22 , the control unit  24  may generate a control signal so that the light source  28  is turned off. In this case, the control unit  24  may turn the light source  28  off by controlling the power supply unit  26 . 
     The control unit  24  may be configured to adjust the illumination of the light source  28 . For example, the control unit  24  may control a magnitude of a current from the power supply unit  28  to the light source  28  to adjust the illumination of the light source  28 . Alternatively, the control unit  24  may control a magnitude of resistance of a circuit for connecting the power supply unit  26  and the light source  28  to each other to adjust the illumination of the light source  28 . 
     The wireless switch  10  and the remote device  20  configured as described above are able to perform turn-on and turn-off operations and adjust the illumination of the light source  28 , while having a simple configuration. 
     As set forth above, according to exemplary embodiments in the present disclosure, a wireless switch not requiring a separate power source may be provided. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.