Abstract:
Provided is an electric apparatus for radio-transmitting a signal between devices by using an optical signal. The electric apparatus is able to continuously perform radio transmission by using an optical signal based on safety standards in a non-normal operating state such an adjustment work, even if safety measures for preventing adverse effects of the optical signal on the human body is suspended. The transmission rate setting unit sets the transmission rate of the signal transmission. The emission intensity control unit sets emission intensity of the optical signal emitted from the light-emitting unit. The notification means notifies a non-normal operating state. The transmission rate setting unit and the emission intensity setting unit, according to the notification means, decrease the transmission rate and the emission intensity of the optical signal while maintaining a bit error rate of the radio transmission set in the normal operating state.

Description:
TECHNICAL FIELD 
       [0001]    The present application relates to an electric apparatus for radio-transmitting signals between devices by using an optical signal and particularly, in a non-normal operating state, relates to an electric apparatus which considers the safety for a human body when using the optical signal for radio transmission. 
       BACKGROUND ART 
       [0002]    Regarding a device using a laser beam, safety standards such as international laser safety standards IEC60825 or its equivalent domestic standards for each country have been established. For example, according to IEC60825-1, the safety standards are divided into classes of class 1 to class 4 based on output power, and manufacturers and users are obliged to comply with various safety consideration matters defined in each class. In a case of the highest safety class 1, safety consideration matters to comply with are not included, and thus it is possible to freely use the laser beam which is likely to be contacted with human bodies. 
         [0003]    Conventionally, a technology relating to an optical transmission device transmitting a main signal and a supervisory channel by combining with each other has been disclosed, in which OSC control means for controlling the supervisory channel includes at least two modes, that is, a normal communication mode and a connection confirmation mode for calculating a time average value of the transmission power of the supervisory channel, in the connection confirmation mode, a signal is controlled to be transmitted with the time-average power lower than the maximum power value based on the laser safety standards, and in the normal communication mode, a signal is controlled to be transmitted with the time-average power exceeding the maximum power value based on the laser safety standards (refer to PTL 1). 
         [0004]    PTL 1: JP-A-2011-147086 
       Technical Problem 
       [0005]    In adjustment work of an electric apparatus such as an electronic component supply device having an optical radio communication device mounted thereon, actually, the adjustment is performed while confirming image data for inspection of the electronic component supply device and operating an XY stage or the like in a state of temporarily removing a protective cover which is provided for safety consideration. Even in this case, communication through the laser beam is necessary for obtaining the image data for inspection or for performing operations such as the XY stage. For safety consideration with respect to the laser beam, workers are required to work while ensuring safety by wearing protective goggles or the like and thus workability of the adjustment work is impaired. 
         [0006]    In the technology disclosed in PTL 1, the supervisory channel is a channel dedicated to confirming a connection between the optical transmission devices in the connection confirmation mode, and instead of the transmission of data by a main signal in a normal operating state, the transmission of a connection confirmation signal is performed. PTL 1 merely discloses the technology which controls different transmission powers between the normal communication mode and the connection confirmation mode when the transmission of the connection confirmation signal is performed. In the supervisory channel, the connection confirmation signal may be transmitted so as to confirm the connection between the optical transmission devices, but is not necessary to transmit data transmitted by the main signal in the normal operating state. Therefore, there is no description with respect to the transmission of the same data as that in the normal operating state in the connection confirmation mode. Accordingly, according to the background art disclosed in PTL 1, it is impossible to transmit data necessary for the adjustment work of the electronic component supply device or the like in a situation where safety measures for the laser beam is suspended in a non-normal operating state. 
         [0007]    The present application has been made in view of such circumstances and an object thereof is to provide an electric apparatus which is able to continuously perform radio transmission by using an optical signal based on safety standards in a non-normal operating state such an adjustment work, even if the safety measure for preventing adverse effects of the optical signal on the human body is suspended. 
       BRIEF SUMMARY 
       [0008]    In order to solve the above-described problem, according to a first aspect of the present application, an electric apparatus for radio-transmitting a signal between devices by using an optical signal includes a transmission rate setting unit, a light-emitting unit, a light-receiving unit, an emission intensity control unit, and notification means. The transmission rate setting unit sets the transmission rate of the signal transmission. The light-emitting unit emits an optical signal. The light-receiving unit receives an optical signal. The emission intensity control unit sets emission intensity of the optical signal emitted from the light-emitting unit. The notification means notifies a non-normal operating state. The transmission rate setting unit and the emission intensity setting unit, according to the notification means, decrease the transmission rate and the emission intensity of the optical signal while maintaining a bit error rate of the radio transmission set in the normal operating state. 
         [0009]    In addition, the electric apparatus according to another aspect of the present application, in which in the signal transmission, the optical signal pertaining to image data requiring a first band in the device and other signals requiring a second band lower than the first band in the device is multiplexed. The transmission rate is decreased so as not to be lower than that of the second band in the aforementioned other signals. 
         [0010]    Further, the electric apparatus according to another aspect of the present application, and the decrease in the transmission rate includes a case where the transmission of the image data is suspended. 
         [0011]    Moreover, the electric apparatus according to another aspect of the present application, further includes a shielding member. The shielding member shields an optical path of the optical signal used for the light-emitting unit, the light-receiving unit, and the radio transmission. The notification means includes an opening and closing detection sensor detecting an opening and closing state of the shielding member. 
       Advantageous Effects 
       [0012]    In the electric apparatus according to the present application, in a case of the non-normal operating state, the transmission rate and the emission intensity are decreased while maintaining the bit error rate of the radio transmission in the normal operating state. Therefore, in the non-normal operating state, it is possible to decrease the emission intensity of the optical signal to the emission intensity based on the safety standards while maintaining the same radio transmission as that in the normal operating state. Here, in the adjustment work performed when forwarding or maintaining devices, the non-normal operating state means an operating state in which the radio transmission is performed while the optical path of the light-emitting unit, the light-receiving unit, and the optical signal is not shielded by a protective cover or the like. 
         [0013]    In the electric apparatus according to the present application, when the optical signal pertaining to the image data and other signals is multiplexed, the transmission rate is decreased so as not to be lower than that of second band necessary for the device regarding other signals in the non-normal operating state. For this reason, in the non-normal operating state, even with the low transmission rate and the emission intensity, it is possible to perform the radio transmission of data necessary for the same operation of the device as in the normal operating state. 
         [0014]    In the electric apparatus according to the present application, the radio transmission of the image data using the optical signal is suspended in the non-normal operating state. For this reason, it is possible to decrease the transmission rate and the emission intensity to the rate not lower than the second band in the non-normal operating state. It is possible to sufficiently decrease the emission intensity while maintaining the band (the second band) of data necessary for the device. 
         [0015]    In the electric apparatus according to the present application, it is possible to detect the non-normal operating state by including the opening and closing detection sensor which detects the opening and closing state of the shielding member. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a perspective view illustrating a panel work machine which is an example of the present application. 
           [0017]      FIG. 2  is a top view illustrating a state where an upper cover of the panel work machine illustrated in  FIG. 1  is removed. 
           [0018]      FIG. 3  is a perspective view illustrating a transporting device which is provided in the panel work machine illustrated in  FIG. 1 . 
           [0019]      FIG. 4  is a block diagram illustrating a control centering on a control device which is provided in the panel work machine illustrated in  FIG. 1 . 
           [0020]      FIG. 5  is a diagram schematically illustrating a configuration of radio transmission by using an optical signal of the panel work machine illustrated in  FIG. 1 . 
           [0021]      FIG. 6  is a block diagram illustrating the control device which is provided in an optical radio device  1 . 
           [0022]      FIG. 7  is a block diagram illustrating the control device which is provided in an optical radio device  3 . 
           [0023]      FIG. 8  is a diagram illustrating a correlationship between a transmission rate and emission intensity of a laser beam in a case where a bit error rate is set to be constant. 
           [0024]      FIG. 9  is a diagram schematically illustrating a packet PA and data included in the packet PA in the respective transmission rates. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Hereinafter, examples of the present application will be described in detail with reference to the drawings as a form of performing the present application. 
       &lt;Configuration of Panel Work Machine&gt; 
       [0026]      FIG. 1  and  FIG. 2  illustrate a panel work machine (hereinafter, referred to as a “work machine” in some cases)  10  which is an example of the present application.  FIG. 1  is a perspective view of the work machine  10  and  FIG. 2  is a top view schematically illustrating the work machine  10  in which an upper cover  21  is removed when viewed from above. The work machine  10  is a circuit component mounting device performing a mounting work of circuit components on a circuit board  12  and includes a transporting device  14  which transports the circuit board  12 , a mounting head  16  which mounts the circuit components on the circuit board  12 , a moving device  18  which moves the mounting head  16 , and a pair of supply devices  20  and  22  which supply the circuit component. 
         [0027]    The transporting device  14  includes, as shown in  FIG. 3 , a pair of conveyor belts  24 , and allows the pair of conveyor belts  24  to be rotated by an electromagnetic motor  26  so as to transport the circuit board  12  held by the conveyor belts  24 . The pair of conveyor belts  24  are configured such that one can be fixed to a base  28  and the other can be moved by the transporting device  14  in the direction perpendicular to the transport direction of the circuit board  12  such that a conveyer width exchange mechanism  30  can allow the other conveyor belt  24  to be close to or far from the one conveyor belt  24 . In other words, the transporting device  14  can change a distance between the pair of conveyor belts  24  so as to transport the circuit boards of different sizes. The transporting device  14  also includes a substrate holding device  32  and fixedly holds the circuit board  12  at a predetermined position (at the position of the circuit board  12  in  FIG. 2 ). Meanwhile, for description of the present example, the transport direction of the circuit board  12  (the longitudinal direction in  FIG. 2 ) by the transporting device  14  is referred to as an X-axis direction and the direction perpendicular to the X-axis direction is referred to as a Y-axis direction. 
         [0028]    In addition, the mounting head  16  is configured to mount the circuit components on the circuit board  12  held by the transporting device  14  and is a mounting head which includes suction nozzles  34  picking the circuit components on a lower surface. The suction nozzles  34  are connected to a negative pressure air path and a positive pressure air path via a positive and negative pressure supply device  36  (refer to  FIG. 4 ), pick and hold the circuit components at negative pressure, and detach the picked circuit components by slightly supplying positive pressure. Further, the mounting head  16  includes a nozzle elevating device  38  (refer to  FIG. 4 ) which elevates the suction nozzle  34  and a nozzle rotation device  40  (refer to  FIG. 4 ) which allows the suction nozzle  34  to be rotated around its axis and thus it is possible to change positions of the circuit components to be held in the perpendicular direction and change posture of the circuit component being held. Meanwhile, the suction nozzles  34  are detachably attached to the mounting head  16  and thus can be changed according to sizes, shapes, or the like of the circuit components. 
         [0029]    The mounting head  16  can be moved to any position on the base  28  by the moving device  18 . In detail, the moving device  18  includes an X-axis direction slide mechanism  50  which is for moving the mounting head  16  in the X-axis direction and a Y-axis direction slide mechanism  52  which is for moving the mounting head  16  in the Y-axis direction. The X-axis direction slide mechanism  50  includes an X-axis slider  54  which is provided on the base  28  so as to be movable in the X-axis direction and an electromagnetic motor  56  (refer to  FIG. 4 ) as a driving source, in which the electromagnetic motor  56  makes the X-axis slider  54  move to any position in the X-axis direction. In addition, the Y-axis direction slide mechanism  52  includes a Y-axis slider  58  which is provided on the side surface of the X-axis slider  54  so as to be movable in the Y-axis direction and an electromagnetic motor  60  (refer to  FIG. 4 ) as a driving source, in which the electromagnetic motor  60  makes the Y-axis slider  58  move to any position in the Y-axis direction. Then, by attaching the mounting head  16  to the Y-axis slider  58 , the mounting head  16  can be moved to any position on the base  28  by the moving device  18 . Meanwhile, the mounting head  16  is detachable from the Y-axis slider  58  at one touch operation and thus it is possible to change different types of the working heads, for example, a dispenser head and the like. 
         [0030]    Further, the pair of supply devices  20  and  22  are disposed with the transporting device  14  interposed therebetween on both side portions of the base  28  in the Y-axis direction. One of the pair of supply devices  20  and  22  is a feeder-type supply device  20  and the other is assumed to be a tray-type supply device  22 . The feeder-type supply device  20  includes a plurality of tape feeders  70  which hold the taped circuit components and feed the circuit components one by one and the circuit components are supplied to the supply position of the mounting head  16  by the respective of tape feeders  70 . On the other hand, the tray-type supply device  22  includes a plurality of component trays  72  on which a plurality of the circuit components are mounted and any one of the plurality of component trays  72  is moved to the supply position of the mounting head  16  by a tray moving mechanism  74  (refer to  FIG. 4 ). 
         [0031]    It should be noted that the respective supply devices  20  and  22  are detachable from the base  28  so as to correspond to a lack of the circuit component to be supplied and to replacement of types of the circuit components, and in order to maintain a state where the respective supply devices  20  and  22  are attached to the base  28 , that is, in order to fix the respective supply devices  20  and  22  to the base  28 , supply device fixing mechanisms  76  and  78  (refer to  FIG. 4 ) are provided. The respective supply devices fixing mechanisms  76  and  78  are switchable between a state in which the supply devices  20  and  22  are locked so as not to be detached from the base  28  and a state of releasing the lock. In other words, it is possible to switch between a state where the replacement of the supply devices  20  and  22  is prohibited and a state where the replacement is allowed. 
         [0032]    In addition, the moving device  18  is provided with an optical radio device  1 . An optical radio device  3  is provided on the side of a control device  90  as a counterpart of the optical radio transmission. The optical radio device  1  is provided in the X-axis slider  54  of the moving device  18  so that an optical axis thereof coincides with that of the optical radio device  3 . Accordingly, it is possible to perform radio transmission of image data, a variety of types of position information, or driving control information through a laser beam, described later, between the optical radio device  1  and the optical radio device  3 . 
         [0033]    In addition, the work machine  10  includes a mark camera  80  (refer to  FIG. 4 ) and a part camera  82  (refer to  FIG. 4 ). The mark camera  80  is fixed to the lower surface of the Y-axis slider  58  in a state of facing downward and moved by the moving device  18 , thereby imaging the surface of the circuit board  12  at an optional position. On the other hand, the part camera  82  is provided in a state of facing upward and can image the circuit component picked and held by the suction nozzles  34  in the mounting head  16 . The image data obtained by the mark camera  80  and the image data obtained by the part camera  82  are processed in an image processing device  84  (refer to  FIG. 4 ) and thus it is possible to obtain information on the circuit board  12 , a holding position error of the circuit board  12  generated due to the substrate holding device  32 , a holding position error of the circuit component generated due to the suction nozzle  34 , or the like. 
         [0034]    Further, the work machine  10  includes a control device  90  as shown in  FIG. 4 . The control device  90  includes a controller  92  which is mainly a computer including CPU, ROM, RAM, or the like, a plurality of driving circuits  94  which corresponds to each of the above described electromagnetic motors  26 ,  56 , and  60 , the conveyer width exchange mechanism  30 , the substrate holding device  32 , the positive and negative pressure supply device  36 , the nozzle elevating device  38 , the nozzle rotation device  40 , the tape feeder  70 , the tray moving mechanism  74 , the supply device fixing mechanisms  76  and  78 , and a control circuit  96  of display devices  86  and  88 . The controller  92  is connected to the image processing device  84  which processes the image data items obtained by the mark camera  80  and the part camera  82 , three detection sensors  98 , and an opening and closing detection sensor  99 . The three detection sensors  98  are disposed on the base  28  between the pair of conveyor belts  24  in a state of facing upward, one is disposed at an end portion of the side into which the circuit board  12  is transported, another one is disposed at an end portion of the side from which the circuit board is transported, and the other is disposed at a position where the circuit board  12  is held by the substrate holding device  32 . 
         [0035]    Information which is obtained by the image data processed by the image processing device  84  such as the information on the circuit board  12 , holding position information on the circuit board  12 , and suction information obtained by the suction nozzle  34  is optically radio-transmitted through the laser beam from the optical radio device  1  which is provided in the moving device  18 , is received in the optical radio device  3  which is connected to the control device  90 , and then is sent to the controller  92 . 
         [0036]    In addition, in the controller  92 , a driving control command is issued with respect to the respective devices  14 ,  18 , and  16  such as the transporting device, the moving device, and the mounting head via the respective driving circuits  94  so as to control operations of the respective devices  14 ,  18 , and  16  such as the transporting device, the moving device, and the mounting head. The drive control commands of operations of respective devices  18  and  16  such as moving device and the mounting head are provided from the controller  92  and received by the optical radio device  1 , which is in the moving device  18 , by using the optical signal transmitted from the optical radio device  3  being connected to the control device  90 . 
         [0037]    In addition, as shown in  FIG. 1 , a pair of display devices  86  and  88  are provided on both side surfaces of the work machine  10  in the Y-axis direction. The respective display devices  86  and  88  display information relating to the mounting work through the mounting head  16  or the like and are a touch panel type display. The display devices  86  and  88  are connected to the controller  92  and operation results of touch buttons displayed on the display devices  86  and  88  are input. In addition, it is possible to display a variety of information via the control circuit  96 . 
         [0038]    In addition, the upper cover  21  is put in the work machine  10  as shown in  FIG. 1 . A transmission line of the optical radio transmission by the laser beam between the optical radio devices  1  and  3  inside the work machine  10  is covered with the upper cover  21 . Accordingly, the laser beam and a light source are shielded to comply with safety consideration matters in the use of the laser beam with respect to the operator for performing such an adjustment work. Moreover, the opening and closing detection sensor  99  (refer to  FIG. 4 ) is a sensor for detecting whether or not the work machine  10  in the interlock mechanism is covered with the upper cover  21 , for example. When a normal operating state where the work machine  10  is covered with the upper cover  21  is detected by the opening and closing detection sensor  99 , the emission intensity of the laser beam is set to be in a high output state required in the normal operating state. In addition, when a state where the transmission line of the optical signal of the work machine  10  is not covered is detected, the emission intensity of the laser beam is set to be in a low output state of class 1 with which safety consideration matters to comply are not required. Even in a case where the optical radio transmission is performed through the laser beam in the low output state, it is possible to transmit a variety of types of signals while maintaining a bit error rate indicating a communication quality via the optical radio devices  1  and  3 . When forwarding or maintaining the work machine  10 , it is possible to perform the adjustment work while maintaining the minimum required optical radio transmission. 
         [0039]    In this case, under the condition in which the bit error rate is constant, the transmission rate is decreased in the radio transmission as the emission intensity of the laser beam is decreased. However, the reduction in transmission rate is the reduction within the range where an update frequency (the band) of data other than the image data or the signal necessary for a variety of devices is secured. For this reason, in the variety of devices, the update frequency of the data or the signal required in terms of the operation or control is maintained as in the normal operating state. During the adjustment work, it is possible to perform the adjustment in a state where the same operation is performed as in the normal operation while securing the safety for the worker by reducing the emission intensity of the laser beam. In this case, the transmission rate of the image data is decreased and the update frequency (the band) of a still image or the like is decreased, but, the data volume of the image data per frame is maintained in the same manner as in the normal operation. It is possible to perform the adjustment work while maintaining the image quality equivalent to that in the normal operating state. In addition, in this case, the update frequency (the band) of the moving image is inevitably decreased, but when the update frequency (the band) of the still image is low enough, even when the transmission rate of the image data is decreased, the image data forming the still image at the update frequency (the band) of the still image is transmitted. Therefore, it is possible to perform the adjustment work while maintaining the image quality equivalent to that in the normal operating state without decreasing the update frequency (the band) of the still image. 
         [0040]    Incidentally, a power source for control and a power source for drive are provided in the work machine  10 , in which the power source for drive is divided into a power source for the transporting device  14  and the supply device fixing mechanisms  76  and  78  and a power source for devices other than the transporting device  14  and the supply device fixing mechanisms  76  and  78 . In other words, the work machine  10  is provided with three power sources, that is, a power source corresponding to the control device  90 , a power source corresponding to the transporting device  14  and the supply device fixing mechanisms  76  and  78 , and a power source corresponding to the moving device  18 . 
         [0041]    Then, in the work machine  10 , with the above described configuration, the optical radio device  1  provided in the moving device  18  and the optical radio device  3  provided in the controller  92  are optically radio-transmitted. Accordingly, the image data processed by the image processing device  84  is transmitted toward the controller  92  from the moving device  18  and the drive control commands of operations of respective devices  18  and  16  such as the moving device and the mounting head are transmitted toward the moving device  18  from the controller  92 . 
         [0042]    Besides this, sensor signals from the detection sensor  98 , the opening and closing detection sensor  99  and the like, command signals from a selection button  105 , an operation button  107 , and a radio button for selection  109 , and signals from sensors (not shown) provided in a variety of types of the drive devices are transmitted to the control device  90 . Thus, it is needless to say that it is possible to use the optical radio transmission even in a case where a variety of types of control signals, display data, and the like are transmitted to the display devices  86  and  88  from the control circuit  96  included in the control device  90 . 
         [0043]      FIG. 5  is a diagram schematically illustrating configurations of the optical radio devices  1  and  3  which are provided in the work machine  10  according to the example and is a diagram schematically illustrating a configuration in which the optical radio devices  1  and  3  are provided between the variety of devices (a camera  8 X, a motor M, a sensor and switch S, or the like described later) and the control device  90  in the work machine  10 . 
         [0044]    The control device  90  is controlled by the controller  92  configured of the computer system such as PC. The controller  92  is connected to one end of a transmission line  7  to which the optical radio device  3  is connected via an image board  90 A, a drive control board  90 B, and an I/O board  90 C. 
         [0045]    The image board  90 A is a board for controlling transmission and reception of the image data. The drive control board  90 B is a board for controlling input and output of an operation command which is a command for operating the electromagnetic motor and servo control information such as torque information or the position information fed back from the electromagnetic motor. The I/O board  90 C is a board for controlling a lamp display or transmission and reception of the signals from a variety of types of the sensors and switches. 
         [0046]    The image board  90 A, the drive control board  90 B, and the I/O board  90 C are connected to one end of the transmission line  7  via the optical radio device  3  and then the optical radio transmission is performed through the laser beam in the transmission line  7 . The other end of the transmission line  7  is connected to the camera  8 X, the electromagnetic motor M, and the sensor and switch S via the optical radio device  1 . Here, the camera  8 X is an imaging device illustrated as an example of the mark camera  80  or the part camera  82  and the electromagnetic motor M is the electromagnetic motors  26 ,  56 , and  60  or other mobile devices as illustrated in  FIG. 4 . Meanwhile, the sensor and switch S is installed, for example, in the transporting device  14 , the mounting head  16 , the moving device  18 , the supply devices  20  and  22 , and the display devices  86  and  88  (refer to  FIG. 4 ) as necessary. 
         [0047]    In the optical radio device  1  as illustrated in  FIG. 5 , the image data imaged by the camera  8 X, the servo control information such as the torque information or the position information obtained by the electromagnetic motor M, and a variety of types of I/O signals output from the sensor and switch S are multiplexed and then are transmitted through the transmission line  7  as the optical radio signal. The transmitted multiplexed signals are received in the optical radio device  3  and then the multiplexing of the signals is released so as to separate signals into individual data. Among the separated data items, the image data is transmitted to the image board  90 A, the servo control information is transmitted to the drive control board  90 B, and the I/O signal is transmitted to the I/O board  90 C. 
         [0048]    The image data, the servo control information, and the I/O signal received in the optical radio device  3  are processed in the controller  92 . A process result from the controller  92  is transmitted through the transmission line  7  from the drive control board  90 B and the I/O board  90 C via the optical radio device  3  as the operation command for controlling the electromagnetic motor M or other mobile devices, and a display signal controlling the display devices  86  and  88 , and then the next control is performed with respect to the electromagnetic motor M or other mobile devices by the optical radio device  1 . 
         [0049]      FIG. 6  is a block diagram illustrating a control device of the optical radio device  1  and  FIG. 7  is a block diagram illustrating a control device of the optical radio device  3 . 
         [0050]    The block diagram (refer to  FIG. 6 ) of the optical radio device  1  will be described. The image data transmitted from the camera  8 X, the servo control information transmitted from electromagnetic motor M, and the I/O signal transmitted from the sensor and switch S are respectively incorporated into an input buffer B 1 . 
         [0051]    The image data, the servo control information, and the I/O signal which are incorporated into the input buffer B 1  are transmitted to a multiplexing unit (MUX) B 2  via the input buffer B 1 . The multiplexing unit (MUX) B 2  controls the ratio of multiplexing data in the normal operating state and the non-normal operating state by using a detection signal S 1  output from the opening and closing detection sensor  99 . 
         [0052]    When notice is given of the normal operating state in which the work machine  10  is covered with the upper cover  21 , in the multiplexing unit (MUX) B 2 , the image data, the servo control information, and the I/O signal, of which data volume is configured, in a packet, to satisfy the update frequency (the band) necessary for the variety of devices in the normal operating state, are transmitted to an error correction coding unit B 3 . 
         [0053]    On the other hand, in the non-normal operating state in which the work machine  10  is not covered with the upper cover  21 , the emission intensity of the laser beam is set to the low output state of class 1 with which safety consideration matters to comply are not required while the bit error rate indicating a communication quality maintains the same rate as in the normal operating state. In response to this, the transmission rate of the radio transmission is decreased. Here, the non-normal operating state is, for example, a state of the adjustment work when forwarding or maintaining the work machine  10 . In this case, the servo control information and the I/O signal preferably secure the update frequency (the band) necessary for the variety of devices. This is because it is possible to operate the variety of devices in the same manner as in the normal operating state even when performing the adjustment work and to perform the adjustment work in the same state as the normal operating state. In a multiplexing unit (MUX) B 2 , with respond to the decrease in the transmission rate, the servo control information and the I/O signal are allocated to each packet so as to be transmitted at the band which satisfies the update frequency (the band) necessary for the variety of devices. As the transmission data volume per unit time is decreased according to the decrease in the transmission rate, adjustment of, for example, increasing the data volume per packet is performed. Note that as for the image data, it is possible to decrease the transmission rate in the normal operating state. However, also in this case, with the configuration for transmitting all of the image data items configuring a frame, regarding a still image, it is possible to maintain the image quality equivalent to that in the normal operating state. The multiplexed data is transmitted to the error correction coding unit B 3 . 
         [0054]    The multiplexed data by the multiplexing unit (MUX) B 2  is transmitted to a data transmission unit B 4  after adding the error correcting code to the error correction coding unit B 3 . In the data transmission unit B 4 , the packet is configured to be transmitted. The data transmission unit B 4  transmits the packet at transmission rates which are controlled to be different in each of the normal operating state and the non-normal operating state by a transmission rate control unit B 5 . A light-emitting module B 6  converts the packet transmitted from the data transmission unit B 4  into the optical signal and then transmits the optical signal to the transmission line  7 . In this case, in the light-emitting module B 6 , the emission intensity of the laser beam is controlled to be different in each of the normal operating state and the non-normal operating state by an emission intensity control unit B 7 . 
         [0055]    In the transmission rate control unit B 5  and the emission intensity control unit B 7 , the control is performed according to the detection signal S 1  outputted from the opening and closing detection sensor  99 . The detection signal S 1  is a signal notifying whether or not the work machine  10  is covered with the upper cover  21 . When the notice is given of the normal operating state, the transmission rate which is set in advance by the transmission rate control unit B 5  is set and the emission intensity of the laser beam which is set in advance by the emission intensity control unit B 7  is set. On the other hand, when notice is given of the non-normal operating state, the transmission rate which is decreased by the transmission rate control unit B 5  is set and the emission intensity of the laser beam which is decreased by the emission intensity control unit B 7  is set in a range where the bit error rate is maintained in the optical radio transmission. The emission intensity of the laser beam is decreased to class 1 with which safety consideration matters to comply are not required. 
         [0056]    The optical radio device  3  (refer to  FIG. 7 ) on the receiving side will be described. The optical signal transmitted through the transmission line  7  is received in a light-receiving module B 21  to be converted into an electrical signal. The electrical signal output from the light-receiving module B 21  is detected by a synchronous circuit B 22  for each bit and then extracted to the multiplexed data. Asynchronous control unit B 23  controls the synchronous circuit B 22  by using the detection signal S 1  output from the opening and closing detection sensor  99 . The control is performed so that the synchronous circuit B 22  is operated at transmission rates which are different in each of the normal operating state and the non-normal operating state. 
         [0057]    The error of the extracted multiplexed data is detected and corrected by an error correction decoding unit B 24 . The error corrected multiplexed data is separated into the respective data items by a demultiplexing unit (DEMUX) B 25 . 
         [0058]    The image data, the servo control information, and the I/O signal are transmitted to the image board  90 A, the drive control board  90 B, and the I/O board  90 C via the respective output buffers B 26 . 
         [0059]      FIG. 8  is a diagram illustrating a correlationship between the transmission rate and the emission intensity of the laser beam in the optical radio devices  1  and  3  in a case where the bit error rate is set to be constant. In  FIG. 8 , an X-axis denotes the transmission rate which is the data volume capable of being transmitted per unit time and Y-axis denotes the emission intensity of the laser beam. 
         [0060]    As shown in  FIG. 8 , in the relationship in which the bit error rate is maintained to be a constant, as the transmission rate between the optical radio devices  1  and  3  increases, there is a need for the high emission intensity for the laser beam. If the transmission rate is assumed to be the transmission rate R 1  in the normal operating state, the emission intensity necessary for the data transmission becomes the emission intensity PW 1  as illustrated in  FIG. 8 . 
         [0061]    The emission intensity of the laser beam is set to be in a low output state of the class 1 with which safety consideration matters to comply are not required. In this case, as illustrated in  FIG. 8 , it is assumed that the emission intensity of the laser beam is emission intensity PW 2  which is an upper limit of the class 1 and the transmission rate is a transmission rate R 2 . The transmission rate of the transmission rate R 2  is decreased and the data volume capable of being transmitted between the optical radio devices  1  and  3  per unit time is decreased compared with the transmission rate R 1  in the normal operating state. 
         [0062]    In a case where the emission intensity is emission intensity PW 3  lower than the emission intensity PW 2 , the transmission rate becomes a transmission rate R 3  which is further lower than the transmission rate R 2 . The transmission rate R 3  is assumed to be the minimum transmission rate necessary for securing the update frequency (the band) necessary for the variety of devices when transmitting the servo control information and the I/O signal other than the image data. In this case, in order to maintain the update frequency (the band) of the servo control information and the I/O signal, the transmission of the image data is set to be in a suspended state. 
         [0063]      FIG. 9  illustrates a configuration example of the packet PA in each of the transmission rates R 1 , R 2 , and R 3 . The data included in the packet PA is the image data A, the servo control information B, and the I/O signal C. The servo control information B and the I/O signal C are the data and signals required in terms of the operation or control in the variety of devices and it is necessary to ensure the update frequency (the band) necessary for the variety of devices. In  FIG. 9 , pieces of k-bits servo control information B 1  to Bk per unit time T and one-bit I/O signal C 1  are used as the update frequency (the band). 
         [0064]    In the transmission rate R 1  which is the transmission rate in the normal operating state, the pieces of k-bits drive control information B 1  to Bk, the one-bit I/O signal C 1 , and items of image data A 1  to An of n bits are transmitted. 
         [0065]    In the non-normal operating state, the emission intensity of the laser beam is decreased to the emission intensity PW 2  which is the upper limit of the class 1, and even when the transmission rate is decreased to the transmission rate R 2  corresponding to this reduction, similar to the transmission rate R 1  in the normal operating state, the pieces of k-bits drive control information B 1  to Bk and the one-bit I/O signal C 1  are transmitted at the unit time T, thereby the updated band necessary for the variety of devices being maintained. On the other hand, as for the image data, items of image data A 1  to Ax of x (x&lt;n) bits are transmitted at the unit time T. Regarding the image data A, the updated band is decreased and the update frequency of the still image is decreased compared with the normal operating state, but if the data volume configuring frames is not changed, it is possible to make the image quality equivalent to the image quality in the normal operating state. 
         [0066]    In the transmission rate R 3 , similar to the transmission rates R 1  and R 2 , it is possible to perform the transmission of the pieces of k-bits drive control information E 1  to Bk and of the one-bit I/O signal C 1  at the unit time T. In this case, the transmission of the image data is suspended. It is preferable when the image data is not particularly necessary for the adjustment work. 
         [0067]    According to the present example, in the non-normal operating state, it is possible to decrease the transmission rate and the emission intensity of the laser beam in the range where the transmission rates are R 2  and R 3  in  FIG. 8  and the emission intensities are PW 2  to PW 3  corresponding to the transmission rates. When the reduction is realized in this range, it is possible to decrease the emission intensity of the laser beam to the class 1 while maintaining the bit error rate according to the transmission, the update frequency (the band) of data other than the image data, or a signal necessary for the variety of devices as the same state as in the normal operation state. Accordingly, it is possible to perform the adjustment work in the same state as the normal operating state while securing the safety for the worker. 
         [0068]    As described in detail, according to the present example, in the optical radio device  1  included in the work machine  10 , the notice is given of the non-normal operating state where the transmission line of the optical signal of the work machine  10  is not covered by the detection signal S 1  output from the opening and closing detection sensor  99 . In this case, the transmission rate control unit B 5  and the emission intensity control unit B 7  decrease the transmission rate while maintaining the bit error rate which is set in advance of the radio transmission in the normal operating state, and perform reduction of the emission intensity of the laser beam to the class 1 with which safety consideration matters to comply are not included. Therefore, in the non-normal operating state, it is possible to perform the radio transmission at the same bit error rate as in the normal operating state, and to decrease the emission intensity of the optical signal to the emission intensity based on the safety standards while maintaining the communication quality of the radio transmission. 
         [0069]    In addition, in the optical radio device  1  included in the work machine  10 , the notice is given of the non-normal operating state. In this case, in the multiplexing unit (MUX) B 2 , the ratio of the respective items of data configuring the packet is controlled so as to decrease the band of the image data while maintaining the update frequency (the band) necessary for the device of the servo control information and the I/O signal. Therefore, the drive control information and the I/O signal are transmitted at a band of the data and signals required in terms of the operation or control in the variety of devices and it is possible to secure the update frequency (the band) necessary for the variety of devices as in the normal operating state. Accordingly, in the non-normal operating state, even with the low transmission rate and the emission intensity, it is possible to perform the radio transmission of data necessary for the operation of the device as in the normal operating state. 
         [0070]    Further, in the transmission rate R 3 , the servo control information and the I/O signal are the minimum required transmission rate for the update frequency (the band) and the emission intensity of the laser beam is decreased to the minimum required value. In this case, in order to maintain the update frequency (the band) of the servo control information and the I/O signal, the transmission of the image data is set to be in a suspended state in the multiplexing unit (MUX) B 2 . Accordingly, it is possible to sufficiently decrease the emission intensity while securing the update frequency (the band) of data necessary for the device. 
         [0071]    In addition, in the opening and closing detection sensor  99  included in the work machine  10 , it is possible to detect the non-normal operating state by detecting whether or not the work machine  10  is covered with the upper cover  21 . 
         [0072]    Note that the present application is not limited to the above described examples, but may be performed in various aspects applied with various modifications and improvements by those who are skilled in the art. For example, in the embodiment, the detection of the normal operating state and the non-normal operating state are not limited to be performed by the opening and closing detection sensor  99 . The detection of the normal operating state and the non-normal operating state may be performed by the selection button  105 , the operation button  107 , the radio button for selection  109 , or the like provided in the display devices  86  and  88  other than the opening and closing detection sensor  99 . 
         [0073]    In the example, the servo control information and the I/O signal are illustrated as examples, but the present application is not limited thereto. It is possible to apply the same configuration to a case of the optical radio transmission of the drive control command of operation of the respective devices  18  and  16  such as the moving device and the mounting head, the command signal from the selection button  105 , the operation button  107 , and the radio button for selection  109 , and the signal from sensor (not shown) which is installed in a variety of types of drive devices or the like and thus the same effect can be achieved as a matter of course. 
         [0074]    Incidentally, according to the above described examples, the panel work machine  10  is an example of the electric apparatus and the data transmission unit, the transmission rate control unit B 5  are examples of a transmission rate setting unit, the light-emitting module B 6  is an example of the light-emitting unit, the light-receiving module B 21  is an example of the light-receiving unit, and the upper cover  21  is an example of the shielding member. 
       REFERENCE SIGN LIST 
       [0000]    
       
         
           
               1 ,  3 : OPTICAL RADIO DEVICE 
               7 : TRANSMISSION LINE 
               10 : PANEL WORK MACHINE 
               8 X: CAMERA 
             M: ELECTROMAGNETIC MOTOR 
             S: SENSOR AND SWITCH 
               90 : CONTROL DEVICE 
               90 A: IMAGE BOARD 
               90 B: DRIVE CONTROL BOARD 
               90 C: I/O BOARD 
               92 : CONTROLLER