Patent Publication Number: US-8125108-B2

Title: Remote control transmitter

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a remote control transmitter for use in remote control operation mainly on various types of electronic equipment. 
     2. Background Art 
     In the recent promotion of enhancing the functionality of various types of electronic equipment, such as a television, video player, and air conditioner, a remote control transmitter capable of ensuring various kinds of operations is also required for remote-controlling such equipment. 
     A description is provided of such a conventional remote control transmitter, with reference to  FIG. 7  and  FIG. 8 .  FIG. 7  is a sectional view of a conventional remote control transmitter. With reference to  FIG. 7 , a plurality of operating bodies made of an insulating resin are placed in a plurality of open holes provided through the top face of box-shaped case  1  made of an insulating resin so that the operating bodies are vertically movable. 
     Pressure-sensitive conductive sheet (hereinafter simply referred to as “conductive sheet”)  3  includes conductive particles dispersed in a base material made of silicone rubber or the like. Wiring board  4  has wiring patterns (not shown) formed on the top and bottom faces thereof. Conductive sheet  3  is placed above the top face of wiring board  4 . On the top face of wiring board  4 , a pair of fixed contacts  5  made of copper, carbon, or the like are formed. 
     Spacer  6  made of an insulating resin is formed between conductive sheet  3  and wiring board  4  so as to surround a plurality of fixed contacts  5 . The bottom face of conductive sheet  3  and fixed contacts  5  are opposed to each other so that a predetermined clearance is provided therebetween. Thus, a plurality of pressure-sensitive conductive contact parts (each hereinafter “contact part”)  7  are formed. Further formed on the bottom face of wiring board  4  are transmission part  8  made of a light emitting diode or the like, and control part  9  made of a microcomputer or the like and causing transmission of a remote control signal from transmission part  8  according to electrical connection in contact part  7  or resistance thereof. Cover  10  made of an insulating resin covers the bottom face of case  1 . 
     While a program list or the like is displayed on the display screen of a liquid crystal device or the like of electronic equipment to be remote-controlled, the conventional remote control transmitter structured as above is directed to the electronic equipment, and one of operating bodies  2  is pressed with a finger. With this operation, the bottom face of this operating body  2  presses conductive sheet  3 . Conductive sheet  3  flexes downwardly and makes contact with a corresponding pair of fixed contacts  5 . The pair of fix contacts  5  is electrically connected via conductive sheet  3 . 
       FIG. 8  is a chart showing a signal waveform supplied from the conventional remote control transmitter. With reference to  FIG. 8 , when one of operating bodies  2  is continuously held down with a constant force, operation signal A 1  is transmitted from transmission part  8  to the remote control receiver periodically and repeatedly at intervals of 20 to 50 msec. Further, when another one of operating bodies  2  is pressed, the electrical connection in corresponding contact part  7  and changes in the resistance between corresponding fixed contacts  5  are detected by control part  9 . A remote control signal corresponding to the pressing operation is transmitted from transmission part  8 . In response to the transmitted remote control signal, the cursor displayed on the display screen of the electronic equipment moves in the downward or horizontal direction, for example. 
     In this manner, the conventional remote control transmitter is structured so that pressing a plurality of operating bodies  2  allows remote control of the moving direction, speed, or the like of the cursor displayed on the display screen of the electronic equipment. 
     Japanese Patent Unexamined Publication No. 2006-33680 is an example of the known information on the conventional techniques related to this invention. 
     However, the conventional remote control transmitter has the following problem. When one of operating bodies  2  is continuously held down with a constant force, the same operation signal A 1  is periodically and repeatedly transmitted from transmitter  8  at predetermined intervals as shown in  FIG. 8 , although the moving direction and speed of cursor  33  on display screen  31  are unchanged. This operation causes continuous power supply from the battery stored in the remote control transmitter to transmission part  8  and control part  9 , thus consuming the battery. 
     SUMMARY OF THE INVENTION 
     The present invention provides a remote control transmitter capable of saving power and making various kinds of remote control operations on equipment. 
     In a remote control transmitter of the present invention, a control part for causing transmission of a remote control signal from a transmission part according to a resistance of a pressure-sensitive conductive contact part causes periodic transmission of a repetition signal, when the resistance of the pressure-sensitive conductive contact part is kept constant. In other words, when an operating body is continuously held down with a constant force and the resistance of the corresponding pressure-sensitive conductive contact part is kept constant, the control part causes periodic transmission of the repetition signal having a smaller number of pulses, at predetermined intervals. 
     In a remote control transmitter of the present invention, a control part for causing transmission of a remote control signal from a transmission part according to a resistance of a pressure-sensitive conductive contact part causes transmission of a continuation signal and thereafter stops transmission, when the resistance of the pressure-sensitive conductive contact part is kept constant. In other words, when an operating body is continuously held down with a constant force and the resistance of the corresponding pressure-sensitive conductive contact part is kept constant, the control part causes transmission of a continuation signal having a predetermined number of pulses and thereafter stops transmission. 
     Such a structure can reduce the consumption of the internal battery. Thus, a remote control transmitter capable of saving power and making various kinds of remote control operations on equipment can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a remote control transmitter in accordance with a first exemplary embodiment of the present invention. 
         FIG. 2  is a sectional view of a pressure-sensitive conductive contact part in the remote control transmitter in accordance with the first exemplary embodiment of the present invention. 
         FIG. 3A  shows a program list displayed on a display screen of electronic equipment. 
         FIG. 3B  shows a program introduction menu displayed on the display screen of the electronic equipment. 
         FIG. 4A  is a chart showing a signal waveform transmitted from the remote control transmitter in accordance with the first exemplary embodiment of the present invention. 
         FIG. 4B  is a chart showing another signal waveform transmitted from the remote control transmitter in accordance with the first exemplary embodiment of the present invention. 
         FIG. 5  is a graph showing the relation between a pressing force applied to an operating body of the remote control transmitter and a resistance between the contacts in accordance with the first exemplary embodiment of the present invention. 
         FIG. 6A  is a chart showing a signal waveform transmitted from a remote control transmitter in accordance with a second exemplary embodiment of the present invention. 
         FIG. 6B  is a chart showing another signal waveform transmitted from the remote control transmitter in accordance with the second exemplary embodiment of the present invention. 
         FIG. 7  is a sectional view of a conventional remote control transmitter. 
         FIG. 8  is a chart showing a signal waveform supplied from the conventional remote control transmitter. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
       FIG. 1  is a sectional view of a remote control transmitter in accordance with the first exemplary embodiment of the present invention.  FIG. 2  is a sectional view of a pressure-sensitive conductive contact part in the remote control transmitter in accordance with the first exemplary embodiment of the present invention. With reference to  FIG. 1  and  FIG. 2 , box-shaped case  1  is made of an insulating resin, such as polystyrene and ABS. Operating bodies  2  made of an insulating resin are placed in corresponding open holes through the top face of case  1  so that the operating bodies are vertically movable. 
     Film-shaped base sheet  11  is made of a flexible material, such as polyethylene terephthalate, polycarbonate, and polyimide. A plurality of pressure-sensitive conductive layers (each hereinafter simply referred to as “conductive layer”)  12  are formed on the bottom face of base sheet  11 . Each of the conductive layers is formed by printing low-resistance layer  12 A having carbon particles dispersed in a synthetic resin, and high-resistance layer  12 B having fine asperities on the bottom face thereof so that both layers are laminated. The sheet resistance of low-resistance layer  12 A is in the range of 0.5 to 30 kΩ/□. The sheet resistance of high-resistance layer  12 B is in the range of 50 kΩ/□ to 5 MΩ/□. 
     Plate-shaped wiring board  13  is made of a paper phenol resin, glass epoxy resin, or the like. A plurality of wiring patterns (not shown) made of a copper foil or the like are formed on the top and bottom faces of wiring board  13 . Base sheet  11  is placed on the top face of wiring board  13  via spacer  15 . Further, on the top face of wiring board  13 , a pair of fixed contacts  14  made of copper, carbon, gold plating, or the like is formed in a comb or semicircular shape. 
     Between base sheet  11  and wiring board  13 , spacer  15  made of an insulating resin, such as epoxy and polyester, is formed so as to surround a plurality of fixed contacts  14 . Spacer  15  allows conductive layers  12  on the bottom face of base sheet  11  to be opposed to corresponding fix contacts  14  with a clearance of 10 to 100 μm provided therebetween. 
     Film-shaped cover sheet  16  has flexibility similar to that of base sheet  11 . Dome-shaped movable contact  17  is formed of a conductive thin metal plate made of a steel, copper alloy, or the like. A plurality of movable contacts  17  are bonded to the bottom face of cover sheet  16  with an adhesive (not shown) made of acrylic, silicone, or the like. The plurality of movable contacts  17  are placed on the top face of base sheet  11  provided on conductive layers  12 . Thus, a plurality of pressure-sensitive conductive contact parts (each hereinafter “contact part”)  18  are formed. 
     The bottom faces of the plurality of operating bodies  2  are in contact with the top faces of movable contacts  17  in the plurality of contact parts  18  via cover sheet  16 . Formed on the bottom face of wiring board  13  are transmission part  8  for transmitting a remote control signal from an electronic component, such as a light emitting diode, and control part  19  for causing transmission of a remote control signal from transmission part  8  according to the electrical connection in contact part  18  and the resistance thereof. Further, the plurality of fixed contacts  14  and transmission part  8  are coupled to control part  19  and the battery power supply (not shown) via the wiring patterns. Cover  10  made of an insulating resin covers the bottom face of case  1 . Thus, a remote control transmitter of the present invention is formed. 
       FIG. 3A  shows a program list displayed on a display screen of electronic equipment.  FIG. 3B  shows a program introduction menu displayed on the display screen of the electronic equipment. With reference to  FIG. 3A  and  FIG. 3B , remote control receiver  32  built in electronic equipment  30 , such as a television, causes various kinds of operations on the equipment, upon receipt of a remote control signal from the remote control transmitter. 
     While a program list, a program introduction menu, or the like is displayed on display screen  31  of the liquid crystal display device or the like of electronic equipment  30  to be remote-controlled, the remote control transmitter is directed to the equipment and one of operating bodies  2  is pressed with a finger. With this operation, the bottom face of this operating body  2  presses the central portion of the top face of corresponding movable contact  17  via cover sheet  16 . Application of a predetermined pressing force resiliently inverts movable contact  17  downward with tactile feedback, thereby flexing base sheet  11  downward. Conductive layer  12  on the bottom face of base sheet  11  is brought into contact with the corresponding pair of fixed contacts  14 , and the pair of fixed contacts  14  is electrically connected via conductive layer  12 . 
       FIG. 4A  is a chart showing a signal waveform transmitted from the remote control transmitter in accordance with the first exemplary embodiment of the present invention. With reference to  FIG. 4A , control part  19  detects electrical connection in contact part  18 , and causes transmission of operation signal A 0  made of pulses combining a plurality of 0s and 1 together with header signal H or the like, from transmission part  8  to electronic equipment  30 , as an infrared remote control signal. The transmitted signal is received by remote control receiver  32  built in electronic equipment  30 . Then, for example, cursor  33  or pointer  34  displayed on display screen  31  is moved upward (see  FIGS. 3A and 3B ). 
       FIG. 5  is a graph showing the relation between a pressing force applied to an operating body of the remote control transmitter and a resistance between the corresponding fixed contacts in accordance with the first exemplary embodiment of the present invention. With reference to  FIG. 5 , as operating body  2  is pressed, the pressing force applied via movable contact  17  increases the area in which high-resistance layer  12 B having fine asperities on the bottom face of conductive layer  12  is in contact with fixed contacts  14  under conductive layer  12 . Therefore, according to pressing forces P 1  and P 2 , the resistance between the pair of fixed contacts  14  is decreased. 
     The changes in the resistance of contact part  18  are detected by control part  19 . Then, as shown in  FIG. 4A , subsequent to operation signal A 0 , operation signal A 1  corresponding to resistance R 1  and operation signal A 2  corresponding to resistance R 2  of  FIG. 5 , for example, are transmitted from transmission part  8  to electronic equipment  30 , as a remote control signal. This signal is received by remote control receiver  32  built in electronic equipment  30 . Then, for example, the moving speed of cursor  33  and pointer  34  is increased. Thus, cursor  33  or pointer  34  displayed on display screen  31  moves upward at a higher speed. 
       FIG. 4B  is a chart showing another signal waveform transmitted from the remote control transmitter in accordance with the first exemplary embodiment of the present invention. With reference to  FIG. 4B , when operating body  2  is continuously held down with a constant force, control part  19  detects that the resistance of corresponding contact part  18  is kept constant without any change. For example, when the operating body is pressed with pressing force P 1  that sets the resistance of contact part  18  at R 1 , subsequent to operation signal A 1  corresponding to resistance R 1 , repetition signal B 1  having a smaller number of pulses than operation signal A 1  is periodically and repeatedly transmitted from transmission part  8  to remote control receiver  32  at intervals of 20 to 50 msec. When remote control receiver  32  receives the remote control signal in which repetition signal B 1  is repeated after operation signal A 1 , cursor  33  or pointer  34  displayed on display screen  31  is moved upward at a constant moving speed corresponding to resistance R 1 . 
     In this manner, pressing operating body  2  causes electrical connection in contact part  18  and changes the resistance thereof. Control part  19  detects such connection and changes, and causes transmission of a remote control signal corresponding to the operation from transmission part  8 . Then, cursor  33  or pointer  34  displayed on display screen  31  is moved downwardly or horizontally, for example. Continuously holding down operating body  2  with a constant force causes cursor  33  or pointer  34  to move at a constant speed. 
     When operating body  2  is continuously held down with a constant force (e.g. pressing force P 1 ), and the resistance of contact part  18  is kept constant at R 1 , control part  19  detects this constant state and causes transmission of a remote control signal in which repetition signal B 1  having a smaller number of pulses is periodically repeated, instead of a remote control signal in which operation signals A 1  and A 2  having a larger number of pulses are repeated. In other words, while operating body  2  is continuously held down with a constant force and the moving direction and speed of cursor  33  or pointer  34  displayed on display screen  31  are kept constant, a remote control signal made of repetition signal B 1  having a smaller number of pulses is transmitted. Such an operation reduces the current consumed by signal transmission and battery consumption in comparison with the case where operation signal A 1  having a larger number of pulses is repeated. 
     In the remote control transmitter of the first exemplary embodiment of the present invention, contact part  18  is formed by opposing conductive layer  12  on the bottom face of base sheet  11  to a pair of fixed contacts  14  with a predetermined clearance provided therebetween, and placing movable contact  17  on the top face of base sheet  11 . With this structure, pressing operating body  2  can provide an excellent operation feel with tactile feedback, and securely brings conductive layer  12  into electrical contact with fixed contacts  14 . Further, low-resistance layer  12 A and high-resistance layer  12 B having fine asperities on the bottom face thereof are laminated to form conductive layer  12 . This structure can provide stable changes in resistance corresponding to changes in pressing force, with few variations. 
     As described above, in the first exemplary embodiment, control part  19  for causing transmission of a remote control signal from transmission part  8  according to the resistance of contact part  18  causes periodic transmission of repetition signal B 1  when the resistance of contact part  18  is kept constant. In other words, when operating body  2  is continuously held down with a constant force and the resistance of contact part  18  is kept constant, control part  19  causes periodic transmission of repetition signal B 1  having a smaller number of pulses at predetermined intervals. This operation can reduce the consumption of the internal battery. Thus, a remote control transmitter capable of saving power and making various kinds of remote control operations on equipment can be provided. 
     Second Embodiment 
       FIG. 6A  is a chart showing a signal waveform transmitted from a remote control transmitter in accordance with the second exemplary embodiment of the present invention.  FIG. 6B  is a chart showing another signal waveform transmitted from the remote control transmitter in accordance with the second exemplary embodiment of the present invention. The signal waveform shown in  FIG. 6A  is identical with the chart of the signal waveform ( FIG. 4A ) transmitted from the remote control transmitter in accordance with the first exemplary embodiment of the present invention. 
     The remote control transmitter of the second exemplary embodiment is different from the remote control transmitter of the first exemplary embodiment in that the transmitter of the second exemplary embodiment generates continuation signal C 1  when operating body  2  is continuously held down with a constant force. With reference to  FIG. 6B , when operating body  2  is continuously held down with a constant force, control part  19  detects that the resistance of corresponding contact part  18  is kept constant. For example, when the operating body is continuously held down with pressing force P 1  that sets the resistance of contact part  18  at R 1 , transmission part  8  transmits operation signal A 1  corresponding to resistance R 1  and subsequently continuation signal C 1 . Thereafter, transmission is stopped. 
     Control part  19  detects the resistance of contact part  18  at predetermined intervals, e.g. 20 to 50 msec. When detecting that the resistance is kept at R 1 , the control part continues to stop transmission. When the resistance at pressing force P 1  is kept at R 1  even after a predetermined time period, e.g. one second, has elapsed, the control part causes transmission of operation signal A 1  and continuation signal C 1  again. While remote control receiver  32  receives this remote control signal, cursor  33  or pointer  34  displayed on display screen  31  is moved at a constant moving speed corresponding to resistance R 1 . 
     When the pressing force applied to operating body  2  is changed from P 1  to P 2 , for example, the resistance of contact part  18  is changed to R 2 . Control part  19  detects this change, and causes transmission of operation signal A 2  corresponding to resistance R 2 . When the resistance is kept at R 2  thereafter, the control part sequentially causes transmission of continuation signal C 1  and stops transmission. While remote control receiver  32  receives this remote control signal, cursor  33  or pointer  34  is moved at a constant moving speed corresponding to resistance R 2 . 
     When the finger is released from operating body  2  and the electrical connection in contact part  18  is broken, control part  19  detects this electrical disconnection and causes transmission of a stop signal (not shown) from transmission part  8 . Thus, cursor  33  or pointer  34  is stopped on a menu item. 
     When operating body  2  is continuously held down with a constant force (e.g. pressing force P 1 ), and the resistance of contact part  18  is kept constant at R 1 , control part  19  detects this constant state and causes transmission of continuation signal C 1  having a predetermined number of pulses, instead of a remote control signal in which operation signals A 1  and A 2  having a larger number of pulses are repeated. Thereafter, the control part stops transmission. In other words, while operating body  2  is continuously held down with a constant force and the moving direction and speed of cursor  33  or pointer  34  displayed on display screen  31  are kept constant, the control part causes transmission of continuation signal C 1  having a predetermined number of pulses and thereafter stops transmission. This operation makes the consumption of the internal battery much smaller than the case of the first exemplary embodiment. 
     Alternatively, when operating body  2  is continuously held down with a constant force (e.g. pressing force P 1 ), the control part may cause transmission of continuation signal C 1  after operation signal A 1  repeated at a predetermined number of times, e.g. three times, instead of causing transmission of continuation signal C 1  immediately after operation signal A 1  as described above. Thereafter, control part  19  detects the resistance at predetermined intervals. Also when the pressing force is changed to P 2 , the control part may cause transmission of continuation signal C 1  after operation signals A 2  repeated at three times. Such an operation prevents erroneous transmission and reception caused by external noises and allows more secure remote control operation. 
     Further, when remote control receiver  32  receives neither continuation signal C 1  nor a stop signal from the remote control transmitter even after a predetermined time period, e.g. one second, has elapsed after receiving operation signal A 1  or A 2  corresponding to constant resistance R 1  or R 2 , respectively, the movement of cursor  33  or pointer  34  displayed on display screen  31  is stopped. Such an operation can prevent cursor  33  or pointer  34  from inadvertently making continuous movement when the remote control signal from the remote control transmitter is interrupted. 
     When control part  19  detects whether the resistance of contact part  18  is kept constant or not, the resistance of contact part  18  is changed in the range of several kilo-ohms to several mega-ohms. Thus, actually, the control part detects changes in the resistance within a predetermined range, in other words, whether the resistance is changed or not in a range covering 5 to 10% of several mega-ohms or the like. 
     As described above, in the second exemplary embodiment of the present invention, when the resistance of contact part  18  is kept constant, control part  19  for causing transmission of a remote control signal from transmission part  8  according to the resistance of contact part  18  causes transmission of continuation signal C 1  and stops transmission. When operating body  2  is continuously held down with a constant force and the resistance of contact part  18  is kept constant, control part  19  causes transmission of continuation signal C 1  having a predetermined number of pulses, and thereafter stops transmission. Such an operation can further reduce the consumption of the internal battery. Thus, a remote control transmitter capable of saving power and making various kinds of remote control operations on equipment can be provided. 
     In each of the above exemplary embodiments, a description is provide of the structure in which a plurality of operating bodies  2  are placed in a plurality of open holes through the top face of case  1  so that the operating bodies are vertically movable. However, the plurality of operating bodies may be integrally formed of an elastic material, such as rubber and elastomer, or a sheet-shaped operating body may be used. Then, a remote control transmitter may be structured so that pressing such an operating body allows operation of movable contact  17  and contact part  18  disposed below. 
     In each of the above exemplary embodiments, a description is provided of the structure in which control part  19  detects electrical connection in contact part  18  or changes in the resistance thereof, and cursor  33  or pointer  34  displayed on display screen  31  of electronic equipment  30  is moved according to changes in the pressing force applied to operating body  2 . However, according to electrical connection in contact part  18  or changes in the resistance thereof, switching operations may be performed in an analog fashion as well as changing the sound volume of electronic equipment  30  and selecting reception channels. Such switching operations include changing the speed of scroll searching of menus, such as a list, displayed on display screen  31 , and changing the speed of reproducing or fast-forwarding moving images. 
     Further, in each of the exemplary embodiments, a description is provided of the structure in which movable contact  17  is placed on contact part  18 , and pressing operating body  2  resiliently inverts movable contact  17  to cause electrical connection in contact part  18  or change the resistance thereof. However, the present invention may have the following structures. Movable contact  17  is eliminated and operating body  2  directly presses contact part  18 . Alternatively, a pressure-sensitive conductive sheet having conductive particles dispersed in a base material is used, and this pressure-sensitive conductive sheet is opposed to the fixed contacts to form pressure-sensitive conductive contact parts. 
     The remote control transmitter of the present invention is capable of saving power and making various kinds of remote control operations on equipment, and is useful mainly for operating various types of electronic equipment.