Abstract:
Disclosed is a semiconductor device, comprising a driver that causes first through third infrared LEDs to emit light sequentially at prescribed times; an infrared light sensor that receives infrared light that is emitted by the first through the third infrared LEDs and reflected by a reflecting object, and generates photoelectric currents at levels corresponding to the intensity of the received infrared light; an amplifier that generates first through third infrared light information, on the basis of the photoelectric current that is generated by the infrared light sensor, and which denote the intensity of the infrared light; an A/D converter; and a linear/logarithmic converter apparatus. It is thus possible to sense the movement of the reflecting object on the basis of the first through the third infrared light information.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a semiconductor device and an electronic apparatus using the same. More specifically, the present invention relates to a semiconductor device for detecting a movement of a reflecting object and to an electronic apparatus using the same. 
       BACKGROUND ART 
       [0002]    Conventionally, a portable telephone having a touch panel of a switch structure allowing key operations and a display device for displaying keys and the like to be operated on the touch panel arranged superposed thereon has been known (see, for example, Japanese Utility Model Laying-Open No. 1-153759 (Patent Literature 1)). 
         [0003]    Further, a portable telephone having a plurality of motion sensors provided in a housing, for monitoring movements corresponding to dial numbers based on output signal patterns of the motion sensors, and dialing accordingly has also been known (see, for example, Japanese Patent Laying-Open No. 2000-78262 (Patent Literature 2)). 
         [0004]    Further, a device analyzing direction, intensity and number of movements detected by a motion detecting unit, analyzing types of user actions by calculating frequency distribution of movements and outputting an operation instruction corresponding to the result of analysis has been known (see, for example, Japanese Patent Laying-Open No. 2000-148351 (Patent Literature 3)). 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PTL 1: Japanese Utility Model Laying-Open No. 1-153759 
         PTL 2: Japanese Patent Laying-Open No. 2000-78262 
         PTL 3: Japanese Patent Laying-Open No. 2000-148351 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0008]    The portable telephone according to Patent Literature 1 is operated by the user directly touching the touch panel and, therefore, it has a problem that the surface of touch panel becomes tainted and sensitivity degrades. 
         [0009]    Portable telephones according to Patent Literatures 2 and 3 require provision of a plurality of motion sensors, resulting in larger size and higher cost of the apparatuses. Further, it is necessary for the user to move the housing and, therefore, there is a possibility that the housing bumps against something and is broken. 
         [0010]    Further, the operation instructing device according to Patent Literature 3 analyzes the type of user action by calculating frequency distribution of movements and, therefore, configuration is complicated. 
         [0011]    Therefore, a main object of the present invention is to provide a semiconductor device capable of detecting a movement of a reflecting object in a contactless manner, without using any motion sensor, as well as to provide an electronic apparatus using the same. 
       Solution to Problem 
       [0012]    The present invention provides a semiconductor device, including: first to N-th (N is an integer not smaller than 2) driving terminals connected to first to N-th infrared emitting units, respectively; a driving unit driving the first to N-th infrared emitting units through the first to N-th driving terminals to cause light emission from the first to N-th infrared emitting units at mutually different timings; a first light receiving unit receiving infrared light emitted from the first to N-th infrared emitting units and reflected by a reflecting object, and generating a photo-electric current of a level corresponding to intensity of the received infrared light; an operation control unit generating first to N-th pieces of infrared light information indicating intensity of infrared light emitted from the first to N-th infrared emitting units respectively and reflected by the reflecting object, based on the photo-electric current generated by the first light receiving unit; and an output terminal for outputting the first to N-th pieces of infrared light information to the outside. 
         [0013]    Preferably, the driving unit supplies first to N-th driving currents to the first to N-th infrared emitting units to cause light emission by the first to N-th infrared emitting units, respectively; and the first to N-th driving currents can be set individually. 
         [0014]    Preferably, the operation control unit controls the driving unit. 
         [0015]    Preferably, the operation control unit removes steady component from the photo-electric current generated at the first light receiving unit, and generates the first to N-th pieces of infrared light information based on the photo-electric current with the steady component removed. 
         [0016]    Preferably, the operation control unit operates in accordance with a control signal, and the device includes an input terminal for applying the control signal from outside to the operation control unit. 
         [0017]    Preferably, the operation control unit includes a register for storing the first to N-th pieces of infrared light information and the control signal. 
         [0018]    Preferably, the semiconductor device further includes a second light receiving unit generating a photo-electric current of a level corresponding to intensity of incident visible light, and the operation control unit generates a piece of visible light information representing intensity of visible light entering the second light receiving unit, based on the photo-electric current generated at the second light receiving unit, and outputs the generated piece of visible light information to the outside through the output terminal. 
         [0019]    Preferably, the semiconductor device further includes a power supply terminal for supplying a power supply voltage from outside to the driving unit and the operation control unit; and a ground terminal for supplying a ground voltage from outside to the driving unit and the operation control unit. 
         [0020]    Further, the present invention provides an electronic apparatus, including: the above-described semiconductor device, and a detecting unit detecting a movement of the reflecting object based on the first to N-th pieces of infrared information from the semiconductor device. 
         [0021]    Further, according to another aspect, the present invention provides a semiconductor device, including: a driving terminal connected to an infrared emitting unit; a driving unit driving the infrared emitting unit through the driving terminal to cause the infrared emitting unit to emit light at a predetermined timing; a light receiving unit receiving light emitted from the infrared emitting unit and reflected by a reflecting object, and generating a photo-electric current of a level corresponding to intensity of the received infrared light; an operation control unit generating a piece of infrared light information representing intensity of infrared light emitted from the infrared emitting unit and reflected by the reflecting object, based on the photo-electric current generated at the light receiving unit; and an output terminal for outputting the piece of infrared light information to the outside. 
         [0022]    Preferably, the operation control unit operates in accordance with a control signal, and the device further includes an input terminal for applying the control signal from the outside to the operation control unit. 
         [0023]    Preferably, the operation control unit includes a register for storing the piece of infrared light information and the control signal. 
         [0024]    According to a further aspect, the present invention provides the above-described semiconductor device, and a detecting unit for detecting a movement of the reflecting object based on the piece of infrared light information from the semiconductor device. 
       Advantageous Effects of Invention 
       [0025]    In the semiconductor device in accordance with the present invention, light is emitted from the first to N-th infrared light emitting units at mutually different timings, the infrared light emitted from the first to N-th infrared light emitting units and reflected from the reflecting object is converted to a photo-electric current by the first light receiving unit, and the first to N-th pieces of infrared light information representing intensities of the infrared light are generated. Therefore, it becomes possible to detect a movement of the reflecting object in contactless manner based on the first to N-th pieces of infrared light information, without using any motion sensor. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0026]      FIG. 1  is a block diagram representing a configuration of the semiconductor device in accordance with an embodiment of the present invention. 
           [0027]      FIG. 2  shows a method of communication between the MCU and the data register shown in  FIG. 1 . 
           [0028]      FIG. 3  shows a configuration of a data register shown in  FIG. 1 . 
           [0029]      FIG. 4  shows a configuration of a register ALS_CONTROL shown in  FIG. 3 . 
           [0030]      FIG. 5  shows a configuration of a register PS_CONTROL shown in  FIG. 3 . 
           [0031]      FIG. 6  shows a configuration of a register I_LED shown in  FIG. 3 . 
           [0032]      FIG. 7  shows a configuration of a register I_LED  33  shown in  FIG. 3 . 
           [0033]      FIG. 8  shows a configuration of a register ALS_PS_MEAS shown in  FIG. 3 . 
           [0034]      FIG. 9  shows a configuration of a register PS_MEAS_RATE shown in  FIG. 3 . 
           [0035]      FIG. 10  shows a configuration of a register ALS_PS_STATUS shown in  FIG. 3 . 
           [0036]      FIG. 11  shows a configuration of a register PS_DATE_LED shown in  FIG. 3 . 
           [0037]      FIG. 12  shows a configuration of a register INTERRUPT shown in  FIG. 3 . 
           [0038]      FIG. 13  shows a configuration of a register PS_TH_LED shown in  FIG. 3 . 
           [0039]      FIG. 14  shows examples of data stored in the register PS_DATE_LED  31  shown in  FIG. 3 . 
           [0040]      FIG. 15  is a time chart representing a method of measuring PS of the semiconductor device shown in  FIG. 1 . 
           [0041]      FIG. 16  is a time chart representing a method of measuring ALS of the semiconductor device shown in  FIG. 1 . 
           [0042]      FIG. 17  is a time chart representing an interrupting function of the semiconductor device shown in  FIG. 1 . 
           [0043]      FIG. 18  shows an appearance of the semiconductor device shown in  FIG. 1 . 
           [0044]      FIG. 19  shows an example of a method of using the semiconductor device shown in  FIG. 1 . 
           [0045]      FIG. 20  shows an arrangement of an infrared LED and the semiconductor device shown in  FIG. 19 . 
           [0046]      FIG. 21  is a circuit block diagram representing a main portion of the portable telephone shown in  FIG. 19 . 
           [0047]      FIG. 22  is a time chart representing a hand gesture detecting function of the portable telephone shown in  FIG. 19 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0048]    A semiconductor device  1  in accordance with an embodiment of the present invention includes, as shown in  FIG. 1 , a proximity sensor  2 , an ambient light sensor  10 , a data register  20 , an oscillator (OSC)  21 , a timing controller  22 , a signal output circuit  23 , a signal input/output circuit  24 , a power-on-reset circuit (POR)  25 , driving terminals T 1  to T 3 , a signal output terminal T 4 , a clock input terminal T 5 , a serial data input/output terminal T 6 , a power supply terminal T 7 , ground terminals T 8  and T 9 , and a test terminal T 10 . 
         [0049]    Driving terminals T 1  to T 3  are connected to cathodes of infrared LEDs (Light Emitting Diodes)  31  to  33 , respectively. Infrared LEDs  31  to  33  all receive, at their anodes, a power supply voltage VDD 1 . Proximity sensor  2  includes a control circuit  3 , a pulse generator  4 , a driver  5 , an infrared sensor  6 , an amplifier  7 , an A/D converter  8 , and a linear/logarithmic converter  9 . Control circuit  3  controls proximity sensor  2  as a whole, in accordance with control signals stored in data register  20 . 
         [0050]    Pulse generator  4  generates a pulse signal for driving infrared LEDs  31  to  33 . Driver  5  maintains each of driving terminals T 1  to T 3  at a high-impedance state, and renders any of the driving terminals T 1  to T 3  grounded in response to the pulse signal generated by pulse generator  4 . It is possible to select, by the signals stored in data register  20 , which one, two, or three of the infrared LEDs  31  to  33  are to be used. Further, it is possible to set, by the signals stored in data register  20 , the current value to be caused to flow through each selected infrared LED and the period of emission by each selected infrared LED (see  FIGS. 3 ,  6 ,  7  and  9 ). 
         [0051]    When any of driving terminals T 1  to T 3  is grounded by driver  5 , current flows through the infrared LED corresponding to the driver terminal, and infrared light is emitted from the infrared LED. The infrared light α emitted from the infrared LED is reflected by a reflecting object  34  and enters infrared sensor  6 . Infrared light from the sun also enters infrared sensor  6 . Infrared sensor  6  is formed, for example, by a photo diode having peak wavelength of 850 nm. Infrared sensor  6  generates a photo-electric current of a level corresponding to the light intensity of incident infrared light α. The photo-electric current contains pulse component derived from the infrared light α from infrared LEDs  31  to  33  and a DC component derived from the infrared light from the sun. 
         [0052]    Amplifier  7  amplifies only the pulse component of photo-electric current generated by infrared sensor  6 , and outputs an analog voltage of a level corresponding to the light intensity of infrared light α incident on infrared sensor  6 . A/D converter  8  converts the analog voltage output from amplifier  7  to a digital signal. The level of analog signal and the numerical value of digital signal are in linear relation. Linear/logarithmic converter  9  calculates a log of the numerical value of the digital signal generated by A/D converter  8 , and stores an 8-bit digital signal representing the calculated log in data register  20  (see  FIGS. 3 and 11 ). 
         [0053]    Ambient light sensor  10  includes a visible light sensor  11 , an amplifier  12 , a capacitor  13 , an A/D converter  14 , and a control circuit  15 . Visible light β generated by a visible light source  35  in the vicinity of semiconductor device  1  enters visible light sensor  11 . Visible light source  35  may be a fluorescent lamp, an incandescent lamp or the sun. Visible light sensor  11  is formed, for example, of a photo diode having peak wavelength of 550 nm. Visible light sensor  11  generates a photo-electric current of a level corresponding to the intensity of incident visible light β. 
         [0054]    Amplifier  12  and capacitor  13  convert the photo-electric current to an analog voltage. A/D converter  14  converts the analog voltage to a 16-bit digital signal and applies it to control circuit  15 . Control circuit  15  controls ambient light sensor  10  as a whole in accordance with control signals stored in data register  20 , and stores the digital signal generated by A/D converter  14  in data register  20  (see  FIGS. 3 and 4 ). 
         [0055]    Oscillator  21  generates clock signals in accordance with the control signals stored in data register  20 . Timing controller  22  controls operation timing of each of proximity sensor  2  and ambient light sensor  10  in synchronization with the clock signals from oscillator  21 . 
         [0056]    Signal output terminal T 4  is connected to an MCU (Micro Control Unit)  36  through a signal line, and connected to a line of a power supply voltage VDD 2  though a resistor element  37 . Output circuit  23  applies an interrupt signal INT to MCU  36 , by setting a signal output terminal T 4  to the grounded state or floating state in accordance with an interrupt signal INT stored in data register  20 . The interrupt signal INT is activated when intensity of infrared light α incident on infrared sensor  6  exceeds a prescribed threshold value, or when intensity of visible light β incident on visible light sensor  11  exceeds a prescribed range. When to activate the interrupt signal INT can be set by signals stored in data register  20  (see  FIGS. 3 ,  10 ,  12  and  13 ). 
         [0057]    A clock input terminal T 5  is connected through a signal line to MCU  36 , and connected to the line of power supply voltage VDD 2  through a resistor element  39 . A serial data input/output terminal T 6  is connected through a signal line to MCU  36 , and connected to the line of power supply voltage VDD 2  through a resistor element  38 . MCU  36  applies the clock signal SCL through signal input/output circuit  24  to data register  20 , by setting clock input terminal T 5  to the grounded state or floating state. Further, MCU  36  applies the serial data signal SDA through signal input/output circuit  24  to data register  20 , by setting serial data input/output terminal T 6  to the grounded state or floating state. 
         [0058]    Data register  20  operates in synchronization with the clock signal SCL applied from MCU  36 , and stores the serial data signal SDA applied from MCU  36  in a selected address. Further, data register  20  operates in synchronization with the clock signal SCL applied from MCU  36 , and reads stored data from a selected address and applies the read data as the serial data signal SDA to MCU  36  through signal input/output circuit  24  and serial data input/output terminal T 6 . 
         [0059]    Output circuit  23  transmits the interrupt signal INT output from data register  20  through signal output terminal T 4  to MCU  36 . If the interrupt signal INT output from data register  20  is at the “H” level, output circuit  23  sets signal output terminal T 4  to a high-impedance state, and if the interrupt signal INT output from data register  20  is at the “L” level, sets signal output terminal T 4  to the “L” level. 
         [0060]    Signal input/output circuit  24  transmits the clock signal SCL applied from MCU  36  through clock input terminal T 5  to data register  20 , and transmits the serial data signal SDA applied from MCU  36  through serial data input/output terminal T 6  to data register  20 . 
         [0061]    Further, signal input/output circuit  24  transmits the serial data signal output from data register  20  through serial data input/output terminal T 6  to MCU  36 . If the data signal output from data register  20  is at the “H” level, signal input/output circuit  24  sets the serial data input/output terminal T 6  to the high-impedance state, and if the data signal output from data register  20  is at the “L” level, sets the serial data input/output terminal to the “L” level. Power-on-reset circuit  25  resets data in data register  20  in response to activation/application of power supply voltage VDD 3 . 
         [0062]    To a power supply terminal T 7 , power supply voltage VDD 3  for driving semiconductor device  1  is applied. Further, to power supply terminal T 7 , one electrode of a capacitor  40  for stabilizing power supply voltage VDD 3  is connected. The other electrode of capacitor  40  is grounded. A ground terminal T 8  is a terminal for letting out current from LEDs  31  to  33 , and it is grounded. A ground terminal T 9  is a terminal for applying ground voltage GND to internal circuits  2  to  15  and  20  to  25  in semiconductor device  1 . A test terminal T 10  is set to the “H” level in a test mode, and is grounded as shown in  FIG. 1  in a normal operation. 
         [0063]      FIG. 2  shows, from (a) to (d), a method of communication between MCU  36  and data register  20 . According to this method of communication, data reading and data writing from a master to a plurality of slaves are possible. Here, MCU  36  is the master and data register  20  is the slave. A slave is selected by a 7-bit slave address (in the figure, 0111000). Typically, a read/write flag is added to the 7-bit slave address. The serial clock signal SCL is output from the master. The slave inputs/outputs the serial data signal SDA in synchronization with the serial clock signal SCL from the master. Specifically, the slave takes in the serial data signal SDA in synchronization with the serial clock signal SCL, and in reverse, outputs the serial data signal SDA in synchronization with the serial clock signal SCL. 
         [0064]    Information communication starts from a start condition ST from the master side and ends at a stop condition SP. The start condition ST is set when the serial data signal SDA changes from the “H” level to the “L” level while the serial clock signal SCL is at the “H” level. The stop condition SP is set when the serial data signal SDA changes from the “L” level to the “H” level while the serial clock signal SCL is at the “H” level. 
         [0065]    Data bits are established while the serial clock signal SCL is at the “H” level. The level of serial data signal SDA is kept constant while the serial clock signal SCL is at the “H” level, and is changed while the serial clock signal SCL is at the “L” level. The data unit is 1 byte (8 bits), and the data is transferred successively from the upper bit. At every 1 byte, the receiving side returns a signal ACK (0 of 1 bit) to the transmitting side. It is also possible to return a signal NACK (1 of 1 bit) after receiving 1 byte. The signal NACK is used when the master notifies the slave of the end of transfer, at the time of data transfer from the salve to the master. 
         [0066]    A series of communications always starts at the start condition ST from the master. One byte immediately following the start condition ST contains 7 bits of slave address and 1 bit of read/write flag. The read/write flag is set to 0 if transfer is from the master to the slave, and it is set to 1 if the transfer is from the slave to the master. When the slave receiving the slave address returns the signal ACK to the master, communication between the master and the slave is established. 
         [0067]    When an address of data register  20  as the slave is to be designated, MCU  36  as the master sets the start condition ST, transmits the slave address of 7 bits, sets the read/write flag to 0, transmits a register address of 1 byte (in the figure, 100xxxxx) in response to the signal ACK from the slave, and transmits the stop condition SP in response to the signal ACK from the slave, as shown in  FIG. 2(   a ). In the figure, “x” represents 0 or 1. 
         [0068]    When data is to be written designating an address of data register  20  as the slave, MCU  36  as the master sets the start condition ST, transmits the slave address of 7 bits, sets the read/write flag to 0, transmits a register address of 1 byte (in the figure, 100xxxxx) in response to the signal ACK from the slave, and transmits the date byte by byte, in response to the signal ACK from the slave. The slave returns the signal ACK every time it receives the data of 1 byte. When the data transmission ends, the master sets the stop condition ST, and the communication ends, as shown in  FIG. 2(   b ). 
         [0069]    When data is to be read designating an address of data register  20  as the slave, MCU  36  as the master sets the start condition ST, transmits the slave address of 7 bits, sets the read/write flag to 0, and transmits a register address of 1 byte (in the figure, 100xxxxx) in response to the signal ACK from the slave, as shown in  FIG. 2(   c ). 
         [0070]    Further, in response to the signal ACK from the slave, the master again sets the start condition ST, transmits the slave address of 7 bits, and sets the read/write flag to 1. The slave returns the signal ACK, and transmits data byte by byte to the master. The master returns the signal ACK every time it receives the data of 1 byte. Receiving the last data, the master returns the signal NACK and then sets the stop condition SP, and thus, the communication ends. 
         [0071]    When data is to be read without designating an address of data register  20  as the slave, MCU  36  as the master sets the start condition ST, transmits the slave address of 7 bits, and sets the read/write flag to 1, as shown in  FIG. 2(   d ). The slave returns the signal ACK, and transmits data byte by byte to the master. The master returns the signal ACK every time it receives the data of 1 byte. Receiving the last data, the master returns the signal NACK and then sets the stop condition SP, and thus, the communication ends. 
         [0072]      FIG. 3  shows the configuration of data register  20 . Referring to  FIG. 3 , addresses  80   h  to  86   h  and  92   h  to  99   h  of data register  20  are used for reading and writing (RW) of information, whereas addresses  8 Ah to  91   h  are used for reading (R) information. Addresses  80   h  to  86   h,    92   h  to  99   h  and  8 Ah to  91   h  each form a register. The address is in hexadecimal notation (h). 
         [0073]    In a register ALS_CONTROL at address  80   h,  pieces of information related to ALS (Ambient Light Sensor) operation mode control and SW (Software) reset are stored. In a register PS_CONTROL at address  81   h,  pieces of information related to PS (Proximity Sensor) operation mode control are stored. In a register I_LED at address  82   h,  pieces of information related to selection of an LED to be activated, and setting of currents of LEDs  31  and  32  are stored. In a register I_LED  33  at address  83   h,  pieces of information related to setting of current of LED  33  are stored. 
         [0074]    In a register ALS_PS_MEAS at address  84   h,  pieces of information related to a forced mode trigger are stored. In a register PS_MEAS_RATE at address  85   h,  pieces of information related to the PS measurement rate in the stand alone mode are stored. In a register ALS_MEAS_RATE at address  86   h,  pieces of information related to the ALS measurement rate in the stand alone mode are stored. In a register PART_ID at address  8 Ah, part number and revised ID (Identification data), specifically, the ID of proximity sensor  2 , are stored. In a register MANUFACT_ID at address  8 Bh, an ID of the manufacturer of semiconductor device  1  is stored. 
         [0075]    In a register ALS_DATA_ 0  at address  8 Ch, a lower byte of result of measurement of ambient light sensor  10  is stored. In a register ALS_DATA_ 1  of address  8 Dh, an upper byte of result of measurement of ambient light sensor  10  is stored. In a register ALS_PS_STATUS at address  8 Eh, pieces of information related to the measurement data and the state of interrupt are stored. 
         [0076]    In a register PS_DATA_LED 31  at address  8 Fh, proximity data from LED  31  (measurement data of infrared light from LED  31 ) is stored. In a register PS_DATA_LED 32  at address  90   h,  proximity data from LED  32  (measurement data of infrared light from LED  32 ) is stored. In a register PS_DATA_LED 33  at address  91   h,  proximity data from LED  33  (measurement data of infrared light from LED  33 ) is stored. 
         [0077]    In a register INTERRUPT at address  92   h,  pieces of information related to setting of interrupt are stored. In a register PS_TH_LED 31  at address  93   h,  PS interrupt threshold value for LED  31  is stored. In a register PS_TH_LED 32  at address  94   h,  interrupt threshold value for LED  32  is stored. In a register PS_TH_LED 33  at address  95   h,  interrupt threshold value for LED  33  is stored. 
         [0078]    In a register ALS_TH_UP_ 0  at address  96   h,  a lower byte of the upper threshold value of ALS is stored. In a register ALS_TH_UP_ 1  at address  97   h,  an upper byte of the upper threshold value of ALS is stored. In a register ALS_TH_LOW_ 0  at address  98   h,  a lower byte of the lower threshold value of ALS is stored. In a register ALS_TH_LOW_ 1  at address  99   h,  an upper byte of the lower threshold value of ALS is stored. 
         [0079]    Next, main registers among the plurality of registers shown in  FIG. 3  will be described in greater detail. As shown in (a) and (b) of  FIG. 4 , addresses ADD 7  to ADD 3  of upper 5 bits of register ALS_CONTROL at address  80   h  are used as a reserve (RES) field, the following 1 bit address ADD 2  is used as an SW reset field, and lower 2 bits ADD 1  and ADD 0  are used as an ALS mode field. To each of addresses ADD 7  to ADD 3 , 0 is written. To address ADD 2 , 0 is written if initial reset is not to be started, and 1 is written if initial reset is to be started. To addresses ADD 1  and ADD 0 , 00 or 01 is written if a standby mode is to be set, 10 is written if the forced mode is to be set, and 11 is written if the stand alone mode is to be set. 
         [0080]    Further, as shown in (a) and (b) of  FIG. 5 , addresses ADD 7  to ADD 2  of upper 6 bits of register PS_CONTROL at address  81   h  are used as an NA field, and lower 2 bits ADD 01  and ADD 0  are used as a PS mode field. Each of addresses ADD 7  to ADD 3  is ignored. To addresses ADD 1  and ADD 0 , 00 or 01 is written if a standby mode is to be set, 10 is written if the forced mode is to be set, and 11 is written if the stand alone mode is to be set. 
         [0081]    Further, as shown in (a) and (b) of  FIG. 6 , addresses ADD 7  and ADD 6  of upper 2 bits of register I_LED at address  82   h  are used as PS activation field, next 3 bits ADD 5  to ADD 3  are used as an electric current field of LED  32 , and lower 3 bits ADD 2  to ADD 0  are used as an electric current field of LED  31 . If LED  31  is to be activated and LEDs  32  and  33  are to be inactivated, 00 is written to upper addresses ADD 7  and ADD 6 . If LEDs  31  and  32  are to be activated and LED  33  is to be inactivated, 01 is written to upper addresses ADD 7  and ADD 6 . If LEDs  31  and  33  are to be activated and LED  32  is to be inactivated, 10 is written to upper addresses ADD 7  and ADD 6 . If all LEDs  31  to  33  are to be activated, 11 is written to upper addresses ADD 7  and ADD 6 . 
         [0082]    To middle addresses ADD 5  to ADD 3 , any of 000 to 111 is written. If the electric current value of LED  32  is to be set to 5, 10, 20, 50, 100 and 150 mA, 000 to 101 are written, respectively. If the electric current value of LED  32  is to be set to 200 mA, either 110 or 111 is written. Therefore, in semiconductor device  1 , it is possible to set the electric current value of LED  32  to a desired value among 5, 10, 20, 50, 100, 150 and 200 mA. 
         [0083]    To lower addresses ADD 2  to ADD 0 , any of 000 to 111 is written. If the electric current value of LED  31  is to be set to 5, 10, 20, 50, 100 and 150 mA, 000 to 101 are written, respectively. If the electric current value of LED  31  is to be set to 200 mA, either 110 or 111 is written. Therefore, in semiconductor device  1 , it is possible to set the electric current value of LED  31  to a desired value among 5, 10, 20, 50, 100, 150 and 200 mA. 
         [0084]    Further, as shown in (a) and (b) of  FIG. 7 , addresses ADD 7  to ADD 3  of upper 5 bits of register I_LED 33  at address  83   h  are used as an NA (No Assign) field, and lower 3 bits ADD 2  to ADD 0  are used as an electric current field of LED  33 . Each of addresses ADD 7  to ADD 3  is ignored. Any of 000 to 111 is written to lower addresses ADD 2  to ADD 0 . If the electric current value of LED  33  is to be set to 5, 10, 20, 50, 100 and 150 mA, 000 to 101 are written, respectively. If the electric current value of LED  33  is to be set to 200 mA, either 110 or 111 is written. Therefore, in semiconductor device  1 , it is possible to set the electric current value of LED  33  to a desired value among 5, 10, 20, 50, 100, 150 and 200 mA. 
         [0085]    Further, as shown in (a) and (b) of  FIG. 8 , addresses ADD 7  to ADD 2  of upper 6 bits of register ALS_PS_MEAS at address  84   h  are used as the NA field, the next 1 bit address ADD 1  is used as an ALS trigger field, and the lower 1 bit ADD 0  is used as a PS trigger field. Addresses ADD 7  to ADD 2  are ignored. To address ADD 1 , if new ALS measurement is not to be started, 0 is written, and if new ALS measurement is to be started, 1 is written. To address ADD 0 , if new PS measurement is not to be started, 0 is written, and if new PS measurement is to be started, 1 is written. 
         [0086]    Further, as shown in (a) and (b) of  FIG. 9 , addresses ADD 7  to ADD 4  of upper 4 bits of register PS_MEAS_RATE at address  85   h  are used as the NA field, and lower 4 bits ADD 3  to ADD 0  are used as a PS measurement rate field. Each of addresses ADD 7  to ADD 4  is ignored. Any of 0000 to 1111 is written to lower addresses ADD 3  to ADD 0 . If PS measurement rate is to be set to 10, 20, 30, 50, 70, 100, 200, 500, 1000 and 2000 msec, 0000 to 1001 are written, respectively. It can be set to 2000 msec by writing any of 1010 to 1111. Therefore, in semiconductor device  1 , PS measurement rate can be set to a desired value from 10 to 2000 msec. 
         [0087]    Further, as shown in (a) and (b) of  FIG. 10 , addresses ADD 7  to ADD 0  of register ALS_PS_STATUS at address  8 Eh are used as INT status field of ALS, data status field of ALS, INT status field of LED  33 , data status field of LED  33 , INT status field of LED  32 , data status field of LED  32 , INT status field of LED  31  and data status field of LED  31 , respectively. 
         [0088]    To address ADD 7 , in ALS measurement, if the signal INT is to be inactivated, 0 is written and if the signal TNT is to be activated, 1 is written. To address ADD 6 , in ALS measurement, if data is already-read old data, 0 is written, and if the data is not-yet-read new data, 1 is written. 
         [0089]    To address ADD 5 , in PS measurement of LED  33 , if the signal INT is to be inactivated, 0 is written and if the signal INT is to be activated, 1 is written. To address ADD 4 , in PS measurement of LED  33 , if data is already-read old data, 0 is written, and if the data is not-yet-read new data, 1 is written. 
         [0090]    To address ADD 3 , in PS measurement of LED  32 , if the signal INT is to be inactivated, 0 is written and if the signal INT is to be activated, 1 is written. To address ADD 2 , in PS measurement of LED  32 , if data is already-read old data, 0 is written, and if the data is not-yet-read new data, 1 is written. 
         [0091]    To address ADD 1 , in PS measurement of LED  31 , if the signal INT is to be inactivated, 0 is written and if the signal INT is to be activated, 1 is written. To address ADD 0 , in PS measurement of LED  31 , if data is already-read old data, 0 is written, and if the data is not-yet-read new data, 1 is written. 
         [0092]    Further, as shown in (a) and (b) of  FIG. 11 , addresses ADD 7  to ADD 0  of register PS_DATA_LED 31  at address  8 Fh are used as data field of LED  31 . In addresses ADD 7  to ADD 0 , PS measurement data of LED  31  are stored. 
         [0093]    Addresses ADD 7  to ADD 0  of register PS_DATA_LED 32  at address  90   h  are used as data field of LED  32 . In addresses ADD 7  to ADD 0 , PS measurement data of LED  32  are stored. 
         [0094]    Addresses ADD 7  to ADD 0  of register PS_DATA_LED 33  at address  91   h  are used as data field of LED  33 . In addresses ADD 7  to ADD 0 , PS measurement data of LED  33  are stored. 
         [0095]    Further, as shown in (a) and (b) of  FIG. 12 , addresses ADD 7  and ADD 4  of register INTERRUPT at address  92   h  are both used as the NA field, and addresses ADD 6  and ADD 5  are used as an interrupt source field. Further, address ADD 3  is used as an output mode field, and address ADD 2  is used as an INT polarity field. Addresses ADD 1  and ADD 0  are used as an interrupt mode field. Addresses Add 7  and ADD 4  are ignored. 
         [0096]    To addresses ADD 6  and ADD 5 , 00 is written if an interrupt is triggered by the ALS, 01 is written if an interrupt is triggered by LED  31 , 10 is written if an interrupt is triggered by LED  32 , and 11 is written if an interrupt is triggered by LED  33 . 
         [0097]    To address ADD 3 , 0 is written if the level of an INT pin (signal output terminal T 4 ) is to be latched until register INTRRUPT is read, and 0 is written if the level of the INT pin is to be updated after each measurement. To address ADD 2 , 0 is written if the INT pin is set to logic 0 (“L” level) when the signal INT is activated, and 1 is written if the INT pin is set to logic 1 (“H” level) when the signal INT is activated. 
         [0098]    To addresses ADD 1  and ADD 0 , 00 is written if the INT pin is to be inactivated (high impedance state), 01 is written if the PS measurement can be triggered, 10 is written if the ALS measurement can be triggered, and 11 is written if the PS and ALS measurements can be triggered. 
         [0099]    Further, as shown in (a) and (b) of  FIG. 13 , addresses ADD 7  to ADD 0  of register PS_TH_LED 31  at address  93   h  are used as a threshold field of LED  31 . In addresses ADD 7  to ADD 0 , a threshold value of LED  31  is stored. 
         [0100]    Addresses ADD 7  to ADD 0  of register PS_TH_LED 32  at address  94   h  are used as the threshold field of LED  32 . In addresses ADD 7  to ADD 0 , a threshold value of LED  32  is stored. 
         [0101]    Addresses ADD 7  to ADD 0  of register PS_TH_LED 33  at address  95   h  are used as the threshold field of LED  33 . In addresses ADD 7  to ADD 0 , a threshold value of LED  33  is stored. 
         [0102]    Further, as shown in  FIG. 14 , addresses ADD 7  to ADD 0  of register PS_DATA_LED  31  at address  8 Fh are used as the PS data field of LED  31 . To addresses ADD 7  to ADD 0 , PS data of LED  31  are stored. By way of example, if 10000101 is written to addresses ADD 7  to ADD 0 , light intensity is represented by 10 A , where A=(2 7 +2 2 +2 0 )×0.097=133×0.097. Therefore, light intensity is 10 A =417 (ρW/cm 2 ). 
         [0103]      FIG. 15  is a time chart representing a measurement sequence of proximity sensor  2 .  FIG. 15  shows an example in which all LEDs  31  to  33  are activated. Infrared LEDs  31  to  33  successively emit light, each for a prescribed time period, in one measurement period. Here, twILED represents duration of an LED current pulse (one emission time period of each infrared LED), which is, for example, 300 μsec, and twILED 2  represents accumulative duration of LED current pulse (time period from the start of emission of infrared LED  31  to stop of emission of infrared LED  33 ), which is, for example, 1 msec. Further, tMPS represents a measurement time of the proximity sensor, which is, for example, 10 msec. The result of measurement is generated within this period tMPS. The PS measurement rate (measurement period) is used only in the stand alone mode, and it is determined by the register PS_MEAS_RATE ( 85   h ) shown in  FIG. 9 . 
         [0104]    If a measurement command is written by the master to register PS_CONTROL ( 81   h ) shown in  FIG. 5 , the first PS measurement is triggered. A combination of infrared LEDs  31  to  33  is set by register I_LED ( 82   h ) shown in  FIG. 6  and register I_LED 33  ( 83   h ) shown in  FIG. 7 . If infrared LED  32  only is to be inactivated, there is no spare time between the pulse of LED  31  and the pulse of LED  33 . 
         [0105]    In the forced mode, the PS measurement is done only once. The PS trigger bit (ADD 0  of  84   h ) is overwritten from 1 to 0 after the completion of PS measurement. When 1 is written to the PS trigger bit by the master, PS measurement is again started. In the stand alone mode, the PS measurement is continued until the master designates another mode. Measurement interval is determined by register PS_MEAS_RATE ( 85   h ) shown in  FIG. 9 . 
         [0106]      FIG. 16  is a time chart representing a measurement sequence of ambient light sensor  10 . In  FIG. 16 , tMALS represents the measurement time of ambient light sensor, which is, for example, 100 msec. The result of measurement is generated within this period. The ALS measurement rate (measurement period) is used only in the stand alone mode, and it is determined by register ALS_MEAS_RATE ( 86   h ). When a measurement command is written by the master to register ALS_CONTROL ( 80   h ) shown in  FIG. 4 , the first ALS measurement is triggered. 
         [0107]    In the forced mode, the ALS measurement is done only once. The ALS trigger bit (ADD 1  of  80   h ) is overwritten from 1 to 0 after the completion of ALS measurement. When 1 is written by the master to the ALS trigger bit, the ALS measurement is again started. In the stand alone mode, the ALS measurement is continued until the master designates another mode. The measurement interval is determined by register ALS_MEAS_RATE ( 86   h ) shown in  FIG. 3 . 
         [0108]      FIG. 17  is a time chart representing, at (a) to (c), the interrupt function. Specifically,  FIG. 17(   a ) represents the interrupt signal INT in a latch mode,  FIG. 17(   b ) represents the interrupt signal INT in a non-latch mode and  FIG. 17(   c ) represents PS measurement value (PS measurement data). As the source of interrupt, ALS measurement and any of the three LEDs  31  to  33  may be selected as the source of interrupt as shown in (a) and (b) of  FIG. 12 . Here, it is assumed that, by way of example, LED  31  is selected as the source of interrupt. 
         [0109]    As shown in  FIG. 15 , the PS measurement value is updated at every measurement period tMPS. The threshold values VTH of LEDs  31  to  33  are stored in register PS_TH_LED ( 93   h,    94   h,    95   h ). If the PS measurement value for LED  31  exceeds the threshold value VTH, the interrupt signal INT makes a transition from the inactive level (“L” level in the figure) to the active level (“H” level in the figure). 
         [0110]    The output mode of interrupt signal INT includes the latch mode and the non-latch mode as shown in (a) and (b) of  FIG. 12 . In the latch mode, the level of interrupt signal INT is latched until the master reads the register INTERRUPT, as shown in (a) of  FIG. 17 . In the non-latch mode, the level of interrupt signal INT is updated after each PS measurement, as shown in (b) of  FIG. 17 . The same applies when LED  32  or  33  is selected as the source of interrupt. 
         [0111]    If the ALS measurement is selected as the source of interrupt, the ALS measurement value is updated at every measurement period tMALS, as shown in  FIG. 16 . The upper threshold value VTHU for the ALS measurement is stored in register ALS_TH_UP ( 96   h,    97   h ) shown in  FIG. 3 . The lower threshold value for the ALS measurement is stored in register ALS_TH_LOW ( 98   h,    99   h ) shown in  FIG. 3 . If the ALS measurement value is between the lower threshold value VTHL and the upper threshold value VTHU, the interrupt signal INT is set to the inactive level (for example, “L” level). If the ALS measurement value is lower than the lower threshold value VTHL, or if the ALS measurement value is higher than the upper threshold value VTHU, the interrupt signal INT is set to the active level (for example, “H” level). 
         [0112]      FIG. 18  shows, at (a) to (d), an appearance of semiconductor device  1 . Specifically, in  FIG. 18 , (a) is a top view of semiconductor device  1 , (b) is a front view, (c) is a bottom view and (d) is a diagram of arrangement of terminals T 1  to T 10  viewed from above semiconductor device  1 . Referring to (a) to (d) of  FIG. 18 , semiconductor device  1  includes a printed circuit board  1   a.  Printed circuit board  1   a  is formed to have a square shape with the length of one side being, for example, 2.8 mm. 
         [0113]    On a surface of printed circuit board  1   a,  circuits  2  to  15  and  20  to  25  shown in  FIG. 1  are mounted. The surface of printed circuit board  1   a  is sealed with transparent resin  1   b.  The height of semiconductor device  1  is, for example, 0.9 mm. On a back surface of printed circuit board  1   a,  terminals T 1  to T 10  are provided. Terminals T 1  to T 10  are arranged in a prescribed order, along four sides of printed circuit board  1   a.    
         [0114]      FIG. 19  shows an example of a method of using semiconductor device  1 . Referring to  FIG. 19 , semiconductor device  1  is mounted, together with three infrared LEDs  31  to  33 , on a portable telephone  50 . Portable telephone  50  is formed to have a longitudinal rectangular shape. At the central portion of portable telephone  50 , a touch panel  51  is provided, and a speaker  52  and a microphone  53  are provided above and below touch panel  51 , respectively. Infrared LED  31  is arranged at an upper right corner on a surface of portable telephone  50 ; infrared LED  32  is arranged at a position a prescribed distance away in the X direction (left direction) in the figure from infrared LED  31 ; and infrared LED  33  is arranged at a position a prescribed distance away in the Y direction (downward direction) in the figure from infrared LED  31 . Semiconductor device  1  is arranged adjacent to infrared LED  31  in the X direction. 
         [0115]      FIG. 20  shows semiconductor device  1  and infrared LED  31  mounted on portable telephone  50 . Referring to  FIG. 20 , semiconductor device  1  and infrared LED  31  are arranged adjacent to each other on a surface of a printed circuit board  54 . On printed circuit board  1   a  of semiconductor device  1 , proximity sensor  2  and ambient light sensor  10  are mounted, and the surface of printed circuit board  1   a  is sealed with transparent resin  1   b.  On printed circuit board  54 , a transparent plate  56  is placed with a light intercepting spacer  55  interposed, and by transparent plate  56 , semiconductor device  1  and infrared LED  31  are protected. 
         [0116]    Infrared light α emitted from infrared LED  31  is reflected by a reflecting object  34  and enters proximity sensor  2 . Proximity sensor  2  stores PS measurement data of the level in accordance with the intensity of incident infrared light α in data register  20 . Reflecting object  34  is, by way of example, an ear or hand of the user of portable telephone  50 . Further, visible light β emitted from visible light source  35  enters ambient light sensor  10 . Ambient light sensor  10  stores ALS measurement data representing illuminance of incident visible light β in data register  20 . 
         [0117]    In portable telephone  50 , MCU  36 , a back light  57  and a driver IC  58  are provided, as shown in  FIG. 21 . Back light  57  provides transmitted light to touch panel  51 . Driver IC  58  drives back light  57  in accordance with a control signal from MCU  36 . MCU  36  controls portable telephone  50  as a whole in accordance with signals from touch panel  51 . Further, MCU  36  controls driver IC  58  and touch panel  51  in accordance with data signals from semiconductor device  1 . 
         [0118]    Specifically, MCU  36  detects illuminance of the place where portable telephone  50  is used from the data signal (ALS measurement data) from semiconductor device  1 , and controls brightness of back light  57  in accordance with the detected illuminance. Thus, an image displayed on touch pane  51  can be made sharp and clear. Further, power consumption can be reduced. 
         [0119]    If it is detected that touch panel  51  of portable telephone  51  comes close to the ear of the user of portable telephone  50  from the data signal (PS measurement data) from semiconductor device  1 , MCU  36  stops the function of touch panel  51 . Thus, erroneous function otherwise caused when the ear of the user of portable telephone  50  touches touch panel  51  can be prevented. 
         [0120]    Further, MCU  36  detects hand gesture of the user of portable telephone  50  based on PS measurement values representing intensity of reflected light of infrared LEDs  31  to  33 , and realizes the scroll operation of images displayed on touch panel  51  in accordance with the result of detection. Specifically, if the user of portable telephone  50  moves his/her hand in the X direction of  FIG. 19  on the surface of portable telephone  50 , infrared LEDs  31  and  33  are first covered by the hand and then infrared LED  32  is covered by the hand. In this case, the intensity of reflected light of infrared LEDs  31  and  33  increases first, and then the intensity of reflected light of infrared LED  32  increases, as shown in  FIG. 22(   a ). If the intensity of reflected light of infrared LEDs  31  to  33  changes in the manner as shown in  FIG. 22(   a ), MCU  36  determines that the user&#39;s hand moved laterally and, by way of example, scrolls the images on touch panel  51  to the lateral direction. 
         [0121]    If the user of portable telephone  50  moves his/her hand in the Y direction of  FIG. 19  on the surface of portable telephone  50 , infrared LEDs  31  and  32  are first covered by the hand and then infrared LED  33  is covered by the hand. In this case, the intensity of reflected light of infrared LEDs  31  and  32  increases first, and then the intensity of reflected light of infrared LED  33  increases, as shown in  FIG. 22(   b ). If the intensity of reflected light of infrared LEDs  31  to  33  changes in the manner as shown in  FIG. 22(   b ), MCU  36  determines that the user&#39;s hand moved longitudinally and, by way of example, scrolls the images on touch panel  51  to the longitudinal direction. 
         [0122]    As described above, by the present embodiment, movement of a reflecting object can be detected in contactless manner without using any motion sensor. Since motion sensor is not used, it is possible to reduce the size, to reduce the cost and to simplify the structure of the apparatus. Further, different from a portable telephone mounting a motion sensor, it is unnecessary to move portable telephone  5  itself. Therefore, it is unlikely that portable telephone  50  bumps against something and is broken while it is moved. 
         [0123]    The embodiments as have been described here are mere examples and should not be interpreted as restrictive. The scope of the present invention is determined by each of the claims with appropriate consideration of the written description of the embodiments and embraces modifications within the meaning of, and equivalent to, the languages in the claims. 
       REFERENCE SIGNS LIST 
       [0124]      1  semiconductor device,  1   a,    54  printed circuit boards,  1   b  transparent resin,  2  proximity sensor,  3 ,  15  control circuits,  4  pulse generator,  5  driver,  6  infrared sensor,  7 ,  12  amplifiers,  8 ,  14  A/D converters,  9  linear/logarithmic converter,  10  ambient light sensor,  11  visible light sensor,  13 ,  40  capacitors,  20  data register,  21  oscillator,  22  timing controller,  23  signal output circuit,  24  signal input/output circuit,  25  power-on-reset circuit,  34  reflecting object,  35  visible light source,  37 - 39  resistor elements,  50  portable telephone,  51  touch panel,  52  speaker,  53  microphone,  54  spacer,  56  transparent plate,  57  back light, T 1 -T 3  driving terminals, T 4  signal output terminal, T 5  clock input terminal, T 6  serial data input/output terminal, T 7  power supply terminal, T 8 , T 9  ground terminal, T 10  test terminal, α infrared light, β visible light