Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of International Application No. PCT/EP2014/060551, filed on May 22, 2014, which claims benefit under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/827,108, filed May 24, 2013. The disclosures of both related applications are considered part of and are incorporated by reference into the disclosure of the present application in their respective entireties. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a switch operating device, a mobile device with the switch operating device and a method for operating a switch with the switch operating device by a presence of a part emitting heat, in particular of a human head. 
     BACKGROUND 
     Interactive systems and their human being-machine-interfaces are known for the human being-computer-interaction, wherein the human being-machine-interfaces are provided with a device for the automatic recognition of non-tactile or tactile gestures performed by human beings. The gesture can principally be derived from every posture and every movement of the body. The gesture recognition device is provided with a device for the acquisition of the gesture, wherein the image information generated thereby is processed with corresponding algorithms in order to derive a gesture out of the information. For example, a mobile telephone is conventionally provided with the gesture recognition device such that with the gesture recognition device it can be detected if the mobile telephone is held at the head of a human being in order to activate, respectively deactivate an associated function of the mobile telephone for telephoning. The gesture recognition device of the mobile telephone for recognizing the presence of the human head is conventionally based on the optical acquisition of the surroundings of the mobile telephone, wherein the presence of the head is considered to be detected as soon as the head is optically acquired by the gesture recognition device. It is hereby to be taken into account that the human head is supposed to be distinguished from other human body parts approaching the mobile telephone, wherein disturbing influences from the surroundings, for example a change of the light conditions, have to be masked out. Further, it is difficult to provide the gesture recognition such that the accuracy during the detection of the presence of the human head is not influenced if the human being wears a cap or a hat or which haircut the human being has, in particular if the human being has long hair or is bald. 
     SUMMARY 
     It is an object of the invention to provide a switch operating device, a mobile device with the switch operating device and a method for operating a switch with the switch operating device by the presence of a part emitting heat, wherein the switch operating device has a miniaturized design with low costs and low energy consumption and the operation of the switch with the switch operating device is secure and has few errors. 
     The switch operating device according to the invention comprises a presence sensor for operating a switch by a presence on the presence sensor of a part emitting heat, wherein the presence is formed by an approach phase during which the part approaches the presence sensor, a remaining phase during which the part remains in the proximity of the presence sensor, and a withdrawal phase during which the part is to be moved away from the presence sensor, wherein the presence sensor is adapted to detect heat emitted by the part with at least one pixel comprising a thin film out of pyroelectric material and to output per pixel a signal with signal deflections according to the temporal intensity curve of the heat detected by the pixel, a signal processing unit with which the approach phase and the withdrawal phase can be determined from the temporal succession and the shape of the signal deflections, and an actuator that is controlled by the signal processing unit and operates the switch when the approach phase, the remaining phase and/or the withdrawal phase is determined. The pyroelectric material is preferably lead-zirconate-titanate. 
     The mobile device according to the invention comprises the switch operating device, wherein the switch is interconnected in the mobile device for activating/deactivating a functionality of the mobile device. 
     The method according to the invention for operating the switch operating device comprises: approaching the part emitting heat on the presence sensor so that the first signal deflection generated in the approach phase is output from the pixel to the signal processing unit, wherein the signal of the pixel is processed by the signal processing unit so that the first signal deflection is identified by the signal processing unit as a first absolute amplitude rise to a first extremum and, after elapsing a first duration from the beginning of the first absolute amplitude rise, a first absolute amplitude decay to an amplitude value which absolute value is between a first predetermined absolute value and the absolute value of the signal level that prevails during a non-affection of the pixel; when the first signal deflection was identified: controlling the actuator for operating the switch by the signal processing unit; from the identification of the first signal deflection: pausing the processing of the signal of the pixel by the signal processing unit for a predetermined waiting duration that forms the waiting phase; withdrawal of the part emitting heat from the approach sensor so that the second signal deflection generated in the withdrawal phase is output from the pixel to the signal processing unit, wherein the signal of the pixel is processed by the signal processing unit, so that the second signal deflection is identified by the signal processing unit as a second absolute amplitude rise to a second extremum and, after elapsing a second duration from the beginning of the second absolute amplitude rise, a second absolute amplitude decay to an amplitude value which absolute value is between a second predetermined absolute amplitude value and the absolute value of the signal level that prevails during a non-affection of the pixel; as soon as the second deflection is identified: controlling the actuator for operating the switch by the signal processing unit. 
     Since the pixel comprises the thin film made out of the pyroelectric material, in particular lead-zirconate-titanate, the pixel that is generated by the part emitting heat during the presence of the part in the proximity of the presence sensor is provided advantageously such that the recognition of the presence of the part emitting heat can be carried out securely and has few errors by the method according to the invention. Furthermore, the presence sensor with the pixel can be made in such a miniaturized design with low costs such that the switch operating device can advantageously be used for the mobile device. The signal is generated with the thin film by the heat emitted by the part so that the presence sensor does not need to be supplied with energy with an external energy source. The switch operating device therefore comprises the signal processing unit and the actuator as energy consumer so that the energy consumption of the switch operating device is advantageously altogether low for the mobile device. 
     The presence sensor preferably comprises at least two pixels. Therefore, two signals generated independently from each other are provided for the signal processing unit, wherein the processing of the signals and the recognition of the presence of the part emitting heat going along therewith is advantageously provided redundantly. 
     The part is preferably a human head and the heat emitted by the part is preferably the body heat radiated from the human head. The recognition of the presence of the human head in the framework of usual human motion sequences is enabled particularly securely and has few errors by the inventive and/or preferred embodiments of the switch operating device. Since the recognition of the presence of the human head is based on the detection of the body heat emitted by the human head, the signals used for the recognition of the presence of the head are almost uninfluenced for example from the type of the haircut of the human being or if the human being wears a head dress. Possible wrong operations of the switch are therefore prevented, wherein the wrong operations are for example caused by long hair or a cap. 
     The method for operating the switch operating device preferably comprises: verifying, if the absolute values of the amplitudes of the signal deflections are above a predetermined amplitude level; if the verification is positive, proceeding with the respective next step. 
     Further, it is preferred that the waiting duration is maximum five seconds. The first duration is preferably maximum between 10 ms and 1000 ms. It is furthermore preferred that the second duration is maximum between 10 ms and 1000 ms. The absolute value of the first predetermined amplitude value is preferably, in relation to the absolute amplitude value of the first extremum, maximum 20% to 50% higher than the absolute value of the signal level that prevails during a non-affection of the pixel. Further, the absolute value of the second predetermined amplitude value is, in relation to the absolute amplitude value of the second extremum, maximum 20% to 50% higher than the absolute value of the signal level that prevails during a non-affection of the pixel. 
     The method for operating the switch operating device further preferably comprises: verifying, if the first extremum is above and the second extremum is below the signal level that prevails during a non-affection of the pixel, or if the first extremum is below and the second extremum is above the signal level that prevails during a non-affection of the pixel; if the verification is positive, proceeding with the method. The approach sensor preferably comprises at least two pixels, wherein it is preferably verified, if the first signal deflections and the second signal deflections of the pixels respectively are within a predetermined duration; if the verification is positive, proceeding with the method. It is hereby preferred that the predetermined duration is 30 ms. 
     By the inventive and/or preferred embodiments of the method for operating the switch operating device it is advantageously achieved that noise signals that, for example, are released by influences from the surroundings of the presence sensor do not or almost not affect the processing by the processing signal unit, whereby the accuracy for the recognition of the presence of the part emitting heat and the operation of the switch is increased. By the inventive and/or preferred definition of the sequences of the signal deflections that are assigned to the presence of the part emitting heat, the accuracy for the recognition of the presence of the part emitting heat out of noise influences on the presence sensor is advantageously high, whereby a secure recognition of the presence of the part emitting heat is enabled, wherein the recognition has few errors. If, for example, the sequences of the signal deflections do not correspond to the signal deflections as they are defined for the presence of the part emitting heat, these signal deflections are not interpreted as a presence of the part emitting heat. By using the signal deflections generated by the thin film made out of the pyroelectric material, in particular lead-zirconate-titanate, for the identification of the presence of the part emitting heat, an increase of the precision of the recognition for the presence of the part emitting heat is achieved in a surprising manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following a preferred embodiment of the invention is explained on the basis of schematic drawings, which show: 
         FIG. 1  a schematic illustration of a mobile telephone that is held on an ear of a human head, 
         FIG. 2  a schematic illustration of a switch operating device according to the invention for the mobile telephone from  FIG. 1 , 
         FIG. 3  a diagram with amplitude curves of signals of a presence sensor from  FIGS. 1 and 2 , and 
         FIGS. 4 and 5  detailed views of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     A human being is shown in  FIG. 1 , wherein the human being holds a mobile telephone  114  at his head  115 . The mobile telephone  114  was brought close to the head  115  with the hand by an approach movement  112 , for example, for a telephone call. If the telephone call has ended, the mobile telephone  114  is withdrawn from the head  115  with a withdrawal movement  111 . The mobile telephone  114  comprises a switch operating device  100  and a functioning unit  113  that can be activated and deactivated with the switch operating device  100 . The functioning unit  113  is for example an illumination device for a display of the mobile telephone  114 , wherein the illumination device is switched by the switch operating device  100  such that the illumination device is deactivated as long as the mobile telephone  114  is held on the head  115 . 
     The mobile telephone  114  is for example switched on, lies on a table and has sufficient reception for receiving telephone calls. In case a telephone call comes in, the mobile telephone  114  rings and the illumination device is switched on for illuminating the display of the mobile telephone  114 . If the human being takes the mobile telephone  114  with the hand and leads it to his head  115  in order to hold the telephone call after taking it, the human being holds the mobile telephone  114  at his ear. As soon as the mobile telephone  114  is in the proximity of the head  115 , the switch operating device  100  deactivates the illumination device in order to decrease the energy consumption of the mobile telephone  114  and not to unnecessarily illuminate the head  115  with the illumination device. 
     As shown in  FIG. 2 , the switch operating device  100  comprises a presence sensor  1  with which it is detected that the mobile telephone  114  is held closely to the head  115 . The presence sensor  1  is interconnected via a signal line  102  with a signal processing unit  101  in which signals transferred from the presence sensor  1  to the signal processing unit  101  are processed. Once the presence of the head  115  in the proximity of the mobile telephone  114  is determined by the signal processing in the signal processing unit  101 , a switch  103  is operated via an actuator  104 . The functioning unit  113  can be activated and deactivated with the switch  103 . 
     The presence sensor  1  comprises a first pixel  21 , a second pixel  22 , a third pixel  23  and a fourth pixel  24 . The pixels  21  to  24  respectively comprise a thin film out of lead-zirconate-titanate, with which a respective signal  51  to  54  is generated, as soon as heat emitted by the head  115  is detected by the respective pixel  21  to  24 . One of the signals  51  to  54  is output from each pixel  21  to  24  to the signal processing unit  101  for example by the presence of the head  115  in the proximity of the presence sensor  1 . The curves of the signals  51  to  54  are analogue and correspond to the temporal intensity curves of the heat emitted by the head  115 , wherein the heat is acquired by the thin films of the pixels  21  to  24 . 
     In  FIGS. 3 to 5  a respective diagram is shown over which ordinate  61  the time is plotted and over which abscissa  62  the amplitudes of the signals  51  to  54  of the pixels  21  to  24  are plotted. The temporal curve of the signals  51  to  54  is substantially congruent. In the signals  51  to  54 , a respective approach phase  31  generated by the approach movement  112  is to be recognized, wherein the approach phase  31  leads to a first signal deflection  56  for the signals  51  to  54 . The first signal deflection  56  is composed of a first absolute amplitude rise  32  and a first absolute amplitude decay  33 . The first absolute amplitude rise  32  begins at a start point in time  91  and the first absolute amplitude decay  33  ends at a first end point in time  92 , wherein each signal  51  to  54  comprises a respective maximum  81  to  84  during transition from the first absolute amplitude rise  32  to the first absolute amplitude decay  33 . 
     A second signal deflection  57  of the signals  51  to  54  is caused in an analogous manner by the withdrawal movement  111 , wherein the second signal deflection  57  comprises a withdrawal phase  41  that is formed by a second absolute amplitude rise  42  and a second absolute amplitude decay  43 . The withdrawal phase  41  of the signals  51  to  54  respectively comprises a minimum  71  to  74 . The signal deflections  56 ,  57  are directed opposite so that according to  FIGS. 2 and 3 , the first signal deflection  56  points upwards and according to  FIGS. 2 and 4 , the second signal deflection  57  points downwards. The start point in time of the second signal deflection  57  is denoted with the reference sign  93  and the end point in time of the second signal deflection  57  is denoted with the reference sign  94 . 
     The signal deflections  56  and  57  are caused by the pixels  21  to  24  due to the dynamic of the approach movement  112  and the withdrawal movement  111 , whereas pixel passivity of the pixels  51  to  54  is present when the head  115  is not present in the proximity of the presence sensor  1  or when the mobile telephone  114  is kept still on the head  115 , wherein the signal level of the pixel passivity is denoted with the reference sign  55 . The absolute amplitude values of the signals output by the pixels  21  to  24  are very low during the pixel passivity, so that in the ideal case, it can be assumed that the signal level  55  is zero. 
     The switch operating device  100  is interconnected such that signals  51  to  54  of the pixels  21  to  24  are permanently output to the signal processing unit  101 . The signals  51  to  54  are processed in real time in the signal processing unit  101  such that, if a temporal succession of the signal deflections  56  and  57  is present. If the first signal deflection  56  is determined by the signal processing unit  101 , the actuator  104  is operated by the signal processing unit  101  such that the switch  103  is opened, so that the functioning unit  113 , for example the display of the mobile telephone  114 , is switched off. As soon as the end point in time  92  of the first signal deflection  56  is determined in the signal processing unit  101 , a waiting phase  44  starts, wherein the waiting phase  44  ends at an end point in time  95 , wherein during the waiting phase  44  the processing of the signals  51  to  54  by the signal processing unit  101  is shut down. The second signal deflection  57  is expected by the signal processing unit  101  only after reaching the end point in time  95  of the waiting phase  44 . As soon as the signal processing unit  101  detects the second signal deflection  57  from among the signals  51  to  54 , the switch  103  is closed via the actuator  104 , so that the functioning unit, for example the display of the mobile telephone  114 , is again switched on. 
     For example a signal deflection in shape of the second signal deflection  57  that occurs during the waiting phase  44  immediately after the first signal deflection  56  is not identified as the second signal deflection  57  by means of the waiting phase  44 , during which the signal processing of the signal processing unit  101  is shut down. It is therefore prevented that a short succession of signal deflections that for example are generated by disturbing influences of the surroundings is wrongly identified as the presence of the mobile telephone  114  on the head  115 . 
     During detecting the presence of the mobile telephone  114  on the head  115  it is to proceed in detail as following: 
     Since the mobile telephone  114  is brought to the head  115  with the approach movement  112  during the approach phase  31 , an increase of heat emitted by the head  115  is detected by the pixels  21  to  24  of the presence sensor  1 . The first signal deflection  56  is therefore respectively output by the pixels  21  to  24  and is identified by the signal processing unit  101 , namely as the first absolute amplitude rise  32  to the respective maximum  81  to  84  and, after elapsing the duration between the start point in time  91  and the end point in time  92  of the first signal deflection  56 , the first absolute amplitude decay  33  to a first amplitude value. The first amplitude value is supposed to be, in relation to the maximum  81  to  84 , maximum 20% to 50% higher as the amplitude value of the signal level  55  that prevails during the non-affection of the pixels  21  to  24 . The duration between the start point in time  91  and the end point in time  92  of the first signal deflection  56  is supposed to be maximum between 20 ms and 50 ms. 
     Once the first signal deflection is identified by the signal processing unit  101 , the actuator  104  is controlled for operating the switch  103 . From the identification of the first signal deflection  56  by the signal processing unit  101 , meaning after elpase of the first end point in time  92  of the first signal deflection  56 , the processing of the signals  51  to  54  by the signal processing unit  101  is stopped during the waiting phase  44  that is supposed to be between two seconds and five seconds. After the end point in time  95  of the waiting phase  44 , the signal processing unit  101  recommences the processing of the signals  51  to  54 . Should the mobile telephone  114  be withdrawn from the head  115  with the withdrawal movement  111  during the waiting phase  44 , the signal processing unit  101  will not be able to identify an expected second signal deflection  57 . Such a short presence of the mobile telephone  114  at the head  115  is not identified as the presence for which the switch operating device  100  is adapted to detect the presence of the mobile telephone  114  at the head  115 . 
     Once the first signal deflection  56  is detected by the signal processing unit  101  and the waiting phase  44  has ended, the signal processing unit  101  is in a state during which the signal processing unit  101  is ready to identify the second signal deflection  57  by processing the signals  51  to  54 . In case the second signal deflection  57  is not identified by the signal processing unit  101  after elapsing a predetermined duration, the signal processing unit  101  is set back in its original state, during which the signal processing unit  101  is ready to again identify the first signal deflection  56 . 
     However, if the second signal deflection  57  can be identified out of the signals  51  to  54  by the signal processing unit  1  before elapsing this predetermined duration, since the mobile telephone  114  was withdrawn from the head  115  with the withdrawal movement  111 , the actuator  104  is controlled by the signal processing unit  101  for operating the switch  103 . The second signal deflection  57  is composed of the second absolute amplitude rise  42  to respectively one of the minima  71  to  74  and, after elapsing the duration between the start point in time  93  and the end point in time  94  of the second signal deflection  57 , the second absolute amplitude decay  43  to a second amplitude value that is supposed to be, in relation to the minimum  71  to  74 , maximum 20% to 50% below the signal level  55  that prevails during the non-affection of the pixels  21  to  24 , wherein the duration is supposed to be maximum between 20 ms and 50 ms. 
     The first signal deflection  56  is identified by the signal processing unit  101  as such, only when the first amplitude value after the first absolute amplitude decay  33  is maximum 20% to 50% of the amplitude difference between the signal level  55  and the amplitude value in the maximum  81  to  84  above the signal level  55 . Further, the second signal deflection  57  is identified by the signal processing unit  101  as such, only when the second amplitude value after the second absolute amplitude decay  43  is maximum 20% to 50% of the amplitude difference between the signal level  55  and the amplitude value in the maximum  81  to  84  above the signal level  55 . 
     It is additionally verified, if the absolute values of the amplitudes of the signal deflections  56 ,  57  are above a predetermined absolute level, whereby noise influences out of the surroundings of the presence sensors  1  are supposed to be masked out. For the identification of the signal deflections  56  and  57  it is furthermore verified, if the maxima  81  to  84  are above and the minima  71  to  74  are below the signal level  55  that prevails during the non-affection of the pixels  21  to  24 . With a corresponding opposite interconnection of the pixels  21  to  24 , it is alternatively conceivable that it is verified, if the orientation of the signal deflections  56  and  57  are opposite to the orientation as they are shown in  FIG. 2 . It is furthermore verified, if respectively the maxima  81  to  83  and the minima  71  to  74  are within a predetermined duration that is 30 ms. It is therefore achieved that the presence of the mobile telephone  114  on the head  115  is only then detected, when all pixels  21  to  24  output the same signal quality of its signals  51  to  54  to the signal processing unit  101 . 
     LIST OF REFERENCE SIGNS 
     
         
           1  presence sensor 
           21  first pixel 
           22  second pixel 
           23  third pixel 
           24  fourth pixel 
           31  approach phase 
           32  first absolute amplitude rise 
           33  first absolute amplitude decay 
           41  withdrawal phase 
           42  second absolute amplitude decay 
           43  second absolute amplitude rise 
           44  waiting phase 
           51  signal of the first pixel 
           52  signal of the second pixel 
           53  signal of the third pixel 
           54  signal of the fourth pixel 
           55  signal level during pixel passivity 
           56  first signal deflection during approach phase 
           57  second signal deflection during withdrawal phase 
           61  ordinate: time 
           62  abscissa: amplitude 
           71  first minimum 
           72  second minimum 
           73  third minimum 
           74  fourth minimum 
           81  first maximum 
           82  second maximum 
           83  third maximum 
           84  fourth maximum 
           91  start point in time of the signal deflection during approach phase 
           92  end point in time of the signal deflection during approach phase
       start point in time waiting phase   
     
           93  start point in time of the signal deflection during withdrawal phase 
           94  end point in time of the signal deflection during withdrawal phase 
           95  end point in time of waiting phase 
           100  switch operating device 
           101  signal processing unit 
           102  signal line 
           103  switch 
           104  actuator 
           111  withdrawal movement 
           112  approach movement 
           113  function unit 
           114  mobile telephone 
           115  head

Technology Category: g