JP2012257129A - Portable terminal, backlight control program and backlight control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of a backlight 40.SOLUTION: A portable telephone 10 includes a display 30, the brightness of which is adjusted by a backlight 40; a 3-axis acceleration sensor 42; and an illuminance sensor 44 which detects the ambient illuminance. In the portable telephone 10, a determination is made as to whether it is in downward state based on the 3-axis acceleration data, and as to whether a desk, or the like, exists near the screen of the display 30 based on the output from the illuminance sensor 44. When the portable telephone 10 is placed on a desk upside down, a determination is made that the portable telephone 10 is in a downward state, and since a determination is also made that an object exists near the screen of the display 30, power supply of the backlight 40 is turned off.

Description

  The present invention relates to a portable terminal, a backlight control program, and a backlight control method, and more particularly to a portable terminal, a backlight control program, and a backlight control method that can adjust the luminance of a display by using a backlight.

  An example of a portable terminal that adjusts the brightness of a display by using a backlight is disclosed in Patent Document 1. In the communication terminal device of Patent Document 1, ambient brightness is detected by an ambient illuminance detection circuit, and the brightness of the display device is controlled. Further, in the electronic device of Patent Document 2, the power supply of the backlight is automatically turned on / off according to the ambient illuminance.

Moreover, in the mobile phone of Patent Document 3, when the display surface of the LCD is placed downward, the backlight is controlled to be turned off. And in the mobile portable terminal of patent document 4, when the inclination angle of a housing | casing is detected with a gravity sensor and it places so that a display part may face below, it determines with it being a state which does not require display. And when it determines in this way, the power supply of a display part is turned off.
JP 2004-96593 A [H04M 1/00, G02F 1/133, G09G 3/20, G09G 3/30, G09G 3/34] Japanese Utility Model Publication No. 4-123437 [G06F 3/147, G02F 1/1335, G06F 1/26, G09G 3/18] JP 2006-101331 A [H04M 1/73, H04B 7/26] JP 2000-307719 [H04M 1/72, H04B 7/26, H04Q 7/38, H04M 1/00, H04M 1/02]

  However, in the communication terminal device of Patent Document 1, the brightness of the display device is only controlled based on the illuminance, and power consumption is not taken into consideration. Further, in the electronic device disclosed in Patent Document 2, if the surroundings become dark, the backlight is turned off, making it difficult to see the display in a dark place. Furthermore, since the backlight is turned off when the mobile phone of Patent Document 3 and the mobile portable terminal of Patent Document 4 are turned downward, it becomes difficult to see the display on the display when the display surface is used face down. End up.

  Therefore, a main object of the present invention is to provide a novel portable terminal, a backlight control program, and a backlight control method.

  Another object of the present invention is to provide a portable terminal, a backlight control program, and a backlight control method that can suppress power consumption of the backlight.

  The present invention employs the following configuration in order to solve the above problems. The reference numerals in parentheses, supplementary explanations, and the like indicate the corresponding relationship with the embodiments described in order to help understanding of the present invention, and do not limit the present invention.

  1st invention is a portable terminal which has a display and the backlight provided in a display, and the brightness | luminance of a display is adjusted with a backlight, Comprising: Based on the attitude | position sensor which detects an attitude | position, the output of an attitude sensor, A first determination unit that determines whether the mobile terminal is in a downward state, an object detection sensor that is provided in the vicinity of the display, detects an object existing nearby, and is close to the display surface of the display based on the output of the object detection sensor A second determination unit that determines whether an object is present, and the first determination unit determines that the mobile terminal is in a downward state, and the second determination unit includes an object near the display surface of the display. The portable terminal includes a control unit that turns off the power of the backlight when it is determined that the backlight is in the active state.

  In 1st invention, the backlight (40) which uses LED as a light source is provided in the display (30) of a portable terminal (10: the referential mark which illustrates the part which respond | corresponds in an Example, and the same hereafter), for example. . Therefore, the brightness of the display is adjusted by the backlight. The attitude sensor (42) outputs acceleration data of three axes, for example, an X axis, a Y axis, and a Z axis. The first determination unit (24, S7) determines whether the portable terminal is in a downward state based on the acceleration data of the three axes output from the attitude sensor. The object detection sensors (44, 46) are provided in the vicinity of the display, and detect an object such as a user's face or a desk using infrared rays or ambient luminance. The second determination unit (24, S9, S25) determines, for example, whether a desk or the like exists near the display surface of the display. When the mobile terminal is placed on the desk, the first determination unit determines that the mobile terminal is in a downward state, and the second determination unit has an object near the display surface of the display. It is determined that this is the state. At this time, the control unit (24, S11) turns off the backlight.

  According to the first invention, it is possible to appropriately determine the state in which the mobile terminal is used and control the on / off of the backlight. Therefore, the power consumption of the backlight can be suppressed without causing the user to feel uncomfortable.

  A second invention is dependent on the first invention, the object detection sensor includes an illuminance sensor that detects ambient illuminance, and the second determination unit displays the display based on the illuminance detected by the illuminance sensor. An illuminance determination unit that determines whether an object is present near the surface is included.

  In the second invention, the illuminance sensor (44) detects the illuminance around the portable terminal. The illuminance determination unit (24, S9) determines whether an object such as a desk exists near the display surface of the display based on the detected change in illuminance.

  A third invention is according to the first invention, wherein the object detection sensor includes a proximity sensor that detects an adjacent object, and the second determination unit is configured to detect the display surface of the display based on a detection result of the proximity sensor. A proximity determining unit that determines whether an object is present nearby is included.

  In the third invention, the proximity sensor (46) detects a nearby object by, for example, reflection of infrared rays. The proximity determination unit (24, S25) determines whether an object such as a desk is in proximity to the display surface of the display based on the detection result of the object by the proximity sensor.

  According to the second and third inventions, it is possible to determine a state where a desk or the like is present near the display surface of the display using the illuminance sensor or the proximity sensor.

  The fourth invention is dependent on the third invention, and further includes a power control unit that turns on the power of the proximity sensor when the first determination unit determines that the downward direction is detected.

  In the fourth invention, the power control unit (24, S21) turns on the power of the proximity sensor when the portable terminal is turned downward.

  According to the fourth invention, power consumption can be suppressed by turning on the power of the proximity sensor only when it is necessary to use the proximity sensor.

  The fifth invention is a display (30), a backlight (40) provided on the display, an attitude sensor (42) for detecting an attitude, and an object for detecting an object (desk) existing in the vicinity of the display. Based on the output of the attitude sensor, the processor (24) of the portable terminal (10) having the detection sensors (44, 46) and the brightness of the display being adjusted by the backlight is adjusted. A first determination unit (S7) for determining, a second determination unit (S9, S25) for determining whether an object is present near the display surface of the display based on the output of the object detection sensor, and a first The determination unit determines that the mobile terminal is in a downward state, and the second determination unit determines that an object is present near the display surface of the display. When in to function control unit to turn off the backlight as (S11), a backlight control program.

  In the fifth invention as well, similarly to the first invention, it is possible to appropriately determine the state in which the mobile terminal is used and control the on / off of the backlight. Therefore, the power consumption of the backlight can be suppressed without causing the user to feel uncomfortable.

  The sixth invention is a display (30), a backlight (40) provided on the display, an attitude sensor (42) for detecting an attitude, and an object for detecting an object (desk) existing in the vicinity of the display. A backlight control method for a portable terminal (10) having a detection sensor (44, 46), wherein the luminance of the display is adjusted by the backlight, wherein the portable terminal is in a downward state based on the output of the attitude sensor (S7), and based on the output of the object detection sensor, it is determined whether an object is present near the display surface of the display (S9, S25), and the portable terminal is in a downward state. And when it is determined that an object is present near the display surface of the display, the backlight is turned off (S11). A backlight control method.

  In the sixth invention as well, similarly to the first invention, it is possible to appropriately determine the state in which the mobile terminal is used and control the on / off of the backlight. Therefore, the power consumption of the backlight can be suppressed without causing the user to feel uncomfortable.

  According to the present invention, the power consumption of the backlight can be suppressed.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is an illustrative view showing an electrical configuration of a mobile phone according to an embodiment of the present invention. FIG. 2 is an illustrative view showing one example of an appearance of the mobile phone shown in FIG. FIG. 3 is an illustrative view showing an example of a display whose luminance is adjusted based on the output of the illuminance sensor shown in FIG. FIG. 4 is an illustrative view showing one example of a situation around the mobile phone shown in FIG. FIG. 5 is an illustrative view showing one example of a memory map of the RAM shown in FIG. FIG. 6 is a flowchart showing an example of the backlight control processing of the first embodiment of the processor shown in FIG. FIG. 7 is a flowchart showing an example of the backlight control process of the second embodiment of the processor shown in FIG.

<First embodiment>
Referring to FIG. 1, a mobile phone 10 is a kind of mobile terminal, and includes a processor 24 called a computer or a CPU. The processor 24 includes a wireless communication circuit 14, an A / D converter 16, a D / A converter 20, a key input device 26, a display driver 28, a flash memory 32, a RAM 34, a touch panel control circuit 36, a backlight 40, An acceleration sensor 42, an illuminance sensor 44, a proximity sensor 46, and the like are connected.

  An antenna 12 is connected to the wireless communication circuit 14. A microphone 18 is connected to the A / D converter 16, and a speaker 22 is connected to the D / A converter 20. A display 30 is connected to the display driver 28. A touch panel 38 is connected to the touch panel control circuit 36.

  The processor 24 manages the overall control of the mobile phone 10. The RAM 34 is used as a work area (including a drawing area) or a buffer area of the processor 24. Content data such as characters, images, sounds, sounds and videos of the mobile phone 10 is recorded in the flash memory 32.

  The A / D converter 16 converts an analog audio signal for audio or sound input through the microphone 18 connected to the A / D converter 16 into a digital audio signal. The D / A converter 20 converts (decodes) the digital audio signal into an analog audio signal, and supplies the analog audio signal to the speaker 22 via an amplifier (not shown). Therefore, sound or sound corresponding to the analog sound signal is output from the speaker 22. The processor 24 can adjust the volume of the sound output from the speaker 22 by controlling the amplification factor of the amplifier.

  The key input device 26 is called an operation unit, and includes a call key, a function key, an end call key, and the like. In addition, information (key data) on keys operated by the user is input to the processor 24. Further, when each key included in the key input device 26 is operated, a click sound is generated. Therefore, the user can obtain an operational feeling for the key operation by listening to the click sound.

  The display driver 28 controls display on the display 30 connected to the display driver 28 under the instruction of the processor 24. The display driver 28 also includes a video memory (not shown) that temporarily stores image data to be displayed.

  The display 30 is provided with a backlight 40 using LEDs as light sources. Then, the processor 24 dims the backlight 40 based on the output of the illuminance sensor 44. The backlight 40 is provided on the display panel included in the display 30 based on the edge light method. Moreover, although LED is employ | adopted as a light source of the backlight 40, in another Example, a cold cathode tube etc. may be employ | adopted. The illuminance sensor 44 includes photodiodes and the like integrated in an array, and detects the illuminance around the mobile phone 10.

  The touch panel 38 is a capacitance method that detects a change in capacitance between electrodes caused by an object such as a finger approaching the surface. For example, it detects that one or more fingers touch the touch panel 38. To do. The touch panel 38 is provided on the display 30 and is a pointing device for instructing an arbitrary position within the screen. The touch panel control circuit 36 detects a touch operation that is pressed, stroked, or touched within the touch range of the touch panel 38, and outputs coordinate data indicating the position of the touch operation to the processor 24. That is, the user can input an operation direction, a figure, or the like to the mobile phone 10 by pressing, stroking, or touching the surface of the touch panel 38 with a finger.

  Here, an operation in which the user touches the upper surface of the touch panel 38 with a finger is referred to as “touch”. On the other hand, the operation of releasing the finger from the touch panel 38 is referred to as “release”. The “touch operation” includes the touch and release described above.

  Also, the coordinates indicated by the touch are referred to as “touch points” (touch start position), and the coordinates indicated by the release are referred to as “release points” (touch end position).

  Note that the touch operation is not limited to a finger, and may be performed with a touch pen with a conductor attached to the tip. Further, as a detection method of the touch panel 38, a surface-type capacitance method may be employed, or a resistance film method, an ultrasonic method, an infrared method, an electromagnetic induction method, or the like may be used.

  The acceleration sensor 42 is a semiconductor triaxial acceleration sensor, and outputs triaxial acceleration data shown in FIGS. 2A and 2B to the processor 24. In addition, the processor 24 calculates an attitude, that is, an angle of the mobile phone 10 by using an inverse trigonometric function with respect to values indicated by the triaxial acceleration data. Therefore, the acceleration sensor 42 functions as a posture sensor that detects the posture of the mobile phone 10.

  Although not shown, the proximity sensor 46 includes an infrared LED as a light emitting element and a photodiode as a light receiving element. The processor 24 calculates the distance of an object (for example, a user's face) close to the proximity sensor 46 (the mobile phone 10) from the change in the output of the photodiode. Specifically, the infrared LED emits infrared rays, and the photodiode receives infrared rays reflected from a face or the like. For example, when the photodiode is far from the user's face, the infrared light emitted by the infrared LED is not received by the photodiode, but when the user's face comes close to the proximity sensor 46, the infrared light emitted by the infrared LED is Reflected on the face and received by the photodiode. Thus, since the amount of received infrared light varies depending on whether the proximity sensor 46 is close to the user's face or not, the processor 24 uses the proximity sensor 46 based on the received light amount. The distance from the object to the object can be calculated.

  In this embodiment, as the proximity sensor 46, an infrared type proximity sensor that uses infrared rays is used. However, an ultrasonic type proximity sensor that uses reflection of ultrasonic waves may be used. . In addition, the proximity sensor 46 is turned off in order to reduce power consumption in a normal state, and turned on as necessary.

  The wireless communication circuit 14 is a circuit for performing wireless communication by the CDMA method. For example, when the user instructs a telephone call (calling) using the key input device 26, the wireless communication circuit 14 executes a telephone call process under the instruction of the processor 24, and sends a telephone call signal via the antenna 12. Is output. The telephone call signal is transmitted to the other party's telephone through a base station and a communication network (not shown). Then, when an incoming call process is performed at the other party's telephone, a communicable state is established, and the processor 24 executes a call process.

  The normal call processing will be described in detail. The modulated audio signal transmitted from the other party's telephone is received by the antenna 12. The received modulated audio signal is demodulated and decoded by the wireless communication circuit 14. The received voice signal obtained by these processes is converted into an analog voice signal by the D / A converter 20 and then output from the speaker 22. On the other hand, the transmission voice signal captured through the microphone 18 is converted into a digital voice signal by the A / D converter 16 and then given to the processor 24. The transmission signal converted into the digital audio signal is subjected to encoding processing and modulation processing by the wireless communication circuit 14 under the instruction of the processor 24, and is output via the antenna 12. Therefore, the modulated voice signal is transmitted to the other party's telephone through the base station and the communication network.

  When a telephone call signal from the other party's telephone is received by the antenna 12, the radio communication circuit 14 notifies the processor 24 of an incoming call (incoming call). In response to this, the processor 24 controls the display driver 28 to display caller information (such as a telephone number) described in the incoming call notification on the display 30. At substantially the same time, the processor 24 outputs a ring tone (sometimes called a ringing melody or a ringing voice) from a speaker (not shown).

  When the user performs a response operation using the call key, the wireless communication circuit 14 executes a telephone call incoming process under the instruction of the processor 24. Further, the communicable state is established, and the processor 24 executes the normal call process described above.

  Further, when a call end operation is performed with the call end key after shifting to the call ready state, the processor 24 controls the wireless communication circuit 14 to transmit a call end signal to the other party. Then, after transmitting the call end signal, the processor 24 ends the call process. The processor 24 also ends the call process when a call end signal is received from the other party first. Furthermore, the processor 24 also ends the call process when a call end signal is received from the mobile communication network regardless of the call partner.

  FIG. 2A is an external view showing the external appearance of the front surface of the mobile phone 10, and FIG. 2B is an external view showing the external appearance of the back surface of the mobile phone 10. Referring to FIG. 2A, the mobile phone 10 has a straight shape and has a flat rectangular casing C. A microphone 18 (not shown) is built in the housing C, and an opening OP2 leading to the built-in microphone 18 is provided on one surface in the longitudinal direction of the housing C. Similarly, the speaker 22 (not shown) is built in the housing C, and the opening OP1 leading to the built-in speaker 22 is provided on the other surface in the longitudinal direction of the housing C.

  The key input device 26 includes a call key, a function key, and an end key. These keys are provided on the surface of the casing C. The display 30 is attached so that the display surface (monitor screen) can be seen from the surface of the housing C. A touch panel 38 is provided on the display surface of the display 30. The illuminance sensor 44 and the proximity sensor 46 are provided on the upper right corner surface of the casing C so that the sensor surface is exposed. In the present embodiment, the illuminance sensor 44 and the proximity sensor 46 are provided adjacent to each other.

  For example, the user inputs a telephone number by performing a touch operation on a dial key displayed on the display 30, and performs a voice call operation using the call key. When the user ends the call, the user performs a call end operation using the end call key. Further, the user operates the function keys to display a menu screen on the display 30. Further, the user performs menu selection and confirmation by touching the soft keys and menus displayed on the display 30.

  Here, as shown in FIG. 2A, a state in which the surface of the mobile phone 10, that is, the display surface of the display 30, can be recognized by the user is referred to as an “upward state” state. On the other hand, as shown in FIG. 2B, a state in which the surface of the mobile phone 10 cannot be recognized by the user is referred to as a “downward state”.

  2 (A) and 2 (B), the acceleration sensor 42 has three axes in the longitudinal direction (Y-axis direction), the lateral direction (X-axis direction), and the thickness direction (Z-axis direction) of the mobile phone 10, respectively. The acceleration of is detected. Further, the acceleration data in the upward state shown in FIG. 2A and the acceleration data in the downward state shown in FIG. 2B are stored in advance. When the acceleration data of the acceleration sensor 42 substantially matches the acceleration data in the upward state, the processor 24 determines that it is in the “upward state”. On the other hand, when the acceleration data of the acceleration sensor 42 substantially matches the acceleration data in the downward state, the processor 24 determines that it is in the “downward state”. For example, the downward state can include a direction substantially parallel to the gravitational acceleration direction (so-called vertical direction), and the upward direction can be a direction substantially parallel to the reverse direction of the gravitational acceleration direction (so-called reverse direction of the vertical direction). Can be mentioned.

  The antenna 12, the wireless communication circuit 14, the A / D 16, the D / A 20, the processor 24, the display driver 28, the flash memory 32, the RAM 34, the touch panel control circuit 36, the backlight 40, and the acceleration sensor 42 are built in the housing C. Therefore, it is not shown in FIGS. 2 (A) and 2 (B).

  FIG. 3 is an illustrative view showing an example of the display 30 in which the luminance is adjusted based on the output of the illuminance sensor 44. First, referring to FIG. 3A, when the mobile phone 10 is in a standby state, for example, the power of the display 30 and the backlight 40 is turned off in order to reduce power consumption. Therefore, the brightness of the display 30 is in the lowest state.

  Next, when a function key or the like is operated, the power of the display 30 is turned on, and a standby image is displayed. At this time, if the illuminance around the mobile phone 10 is low as shown in FIG. 3B, the backlight 40 is dimmed. On the other hand, as shown in FIG. 3C, if the illuminance around the mobile phone 10 is high, the backlight 40 is dimmed. That is, when the surroundings are dark, the backlight 40 is dimmed and the brightness of the display 30 is lowered to make the display content easier to see. On the other hand, when the surroundings are bright, the backlight 40 is brightened and the brightness of the display 30 is increased, so that the display content is easy to see.

  Here, in the present embodiment, the power of the backlight 40 is turned on / off according to the situation in which the mobile phone 10 is used. For example, as shown in FIG. 4A, when the mobile phone 10 is turned down on a desk in a downward state, it is considered that the user is not using the mobile phone 10, so the display 30 and the backlight 40 are not used. The power is turned off. In other words, if the illuminance value based on the output of the illuminance sensor 44 is determined to be a downward state based on the output of the acceleration sensor 42 and the illuminance value based on the output of the illuminance sensor 44 is equal to or less than the threshold value, the backlight 40 is turned off as shown in FIG. To be.

  Further, as shown in FIG. 4B, if the display content is held in the downward state and the display content of the display 30 is confirmed by the user, the brightness of the backlight 40 is dimmed. That is, even if it is determined to be in the downward state, if the illuminance value is larger than the threshold value, the backlight 40 is dimmed based on the output of the illuminance sensor 44.

  In this way, it is possible to appropriately determine the state in which the mobile phone 10 is used by using the two sensors, and to control the on / off of the backlight 40. Therefore, the power consumption of the backlight 40 can be suppressed without giving the user a sense of incongruity.

  In the present embodiment, the backlight 40 is turned off in order to reduce power consumption even when a non-operation state in which no touch operation or key operation is performed for a predetermined time or longer after the backlight 40 is turned on. Is done.

  FIG. 5 is a diagram showing a memory map of the RAM 34. The memory map of the RAM 34 includes a program storage area 302 and a data storage area 304. A part of the program and data is read from the flash memory 32 all at once or partly and sequentially as necessary, stored in the RAM 34, and then processed by the processor 24.

  The program storage area 302 stores a program for operating the mobile phone 10. For example, the program for operating the mobile phone 10 includes a backlight control program 310 and the like. The backlight control program 310 is a program for controlling the brightness of the backlight 40 and power on / off.

  Although illustration is omitted, the program for operating the mobile phone 10 includes a program for notifying the voice incoming state and a program for controlling the display on the display 30.

  Subsequently, in the data storage area 304, an acceleration buffer 330, an attitude buffer 332, an illuminance buffer 334, a distance buffer 336, and the like are provided, and a lighting counter 338 is also provided.

  The acceleration buffer 330 temporarily stores acceleration data for each of the three axes output from the acceleration sensor 42. The posture buffer 332 temporarily stores the posture (upward or downward state) of the mobile phone 10 calculated from the acceleration data of each axis stored in the acceleration buffer 330. The illuminance buffer 334 temporarily stores the illuminance value obtained based on the output of the illuminance sensor 44. The distance buffer 336 temporarily stores a distance value calculated based on the output of the proximity sensor 46.

  The lighting counter 338 is a counter for measuring a predetermined time (for example, 10 seconds), and starts counting when initialized. Therefore, the lighting counter 338 is also called a lighting timer. When the backlight 40 is turned on and is lit, the lighting counter 338 is initialized and starts counting.

  Although not shown, the data storage area 304 stores image data displayed in a standby state, a table that records the brightness of the backlight 40 corresponding to a plurality of illuminance values, and the like. Counters and flags necessary for the operation of the mobile phone 10 are also provided.

  The processor 24 processes a plurality of tasks including the backlight control program shown in FIG. 6 in parallel under the control of a Linux (registered trademark) -based OS such as Android (registered trademark) and REX, and other OSs. To do.

  FIG. 6 is a flowchart of the backlight control process. For example, when the function key is operated in the standby state, the processor 24 turns on the backlight 40 in step S1, and resets the lighting timer in step S3. That is, in step S3, measurement of the time after the backlight 40 is turned on is started. Subsequently, in step S5, the backlight 40 is dimmed based on the illuminance value. For example, if the ambient illuminance is as shown in FIG. 3A, the brightness of the backlight 40 is adjusted to be dark.

  Subsequently, in step S7, it is determined whether or not the posture is a downward state. That is, it is determined whether or not the posture stored in the posture buffer 332 indicates the downward state illustrated in FIG. The processor 24 that executes the process of step S7 functions as a first determination unit.

  If “NO” in the step S7, for example, if the mobile phone 10 is in the upward state shown in FIG. 2A, the process proceeds to a step S13. If “YES” in the step S7, that is, if the mobile phone 10 is in the downward state shown in FIG. 2B, it is determined whether or not the illuminance value is equal to or less than a threshold value in a step S9. That is, in step S9, it is determined whether or not the mobile phone 10 is in a state of being laid on a desk or the like. The processor 24 that executes the process of step S9 functions as a second determination unit and an illuminance determination unit.

  If “YES” in the step S9, that is, if the mobile phone 10 is hung on the desk as shown in FIG. 4A and the illuminance value is equal to or less than the threshold value, the power source of the backlight 40 in the step S11. Is turned off and the backlight control process is terminated. And the processor 24 which performs the process of step S11 functions as a control part.

  On the other hand, if “NO” in the step S9, for example, the mobile phone 10 is in the state shown in FIG. 4B, and if the illuminance value is larger than the threshold value, it is determined whether or not the lighting timer has expired in a step S13. To do. For example, in step S13, it is determined whether or not a predetermined time (for example, 10 seconds) has elapsed since the backlight 40 was turned on in a no-operation state. If “YES” in the step S13, that is, if a predetermined time elapses in the non-operation state, the process proceeds to a step S11.

  On the other hand, if “NO” in the step S13, that is, if the predetermined time has not passed while the mobile phone 10 is not operated, it is determined whether or not the illuminance value has changed in a step S15. That is, the processor 24 monitors the illuminance value temporarily stored in the illuminance buffer 334 to determine whether the illuminance around the mobile phone 10 has changed. If “YES” in the step S15, that is, if the illuminance around the mobile phone 10 is changed, the process returns to the step S5. That is, the luminance of the display 30 is readjusted according to the changed ambient illuminance.

  On the other hand, if “NO” in the step S15, that is, if the illuminance around the mobile phone 10 is not changed, it is determined whether or not the operation is performed in a step S17. For example, it is determined whether or not the user has performed a touch operation or key operation on the mobile phone 10. If “NO” in the step S17, that is, if no operation is performed on the mobile phone 10, the process returns to the step S7. That is, the posture, change in illuminance, and the like are determined again. On the other hand, if “YES” in the step S17, that is, if a touch operation or a key operation is performed, the process returns to the step S3. That is, the lighting timer is reset and the brightness of the display 30 is readjusted according to the user's operation.

<Second embodiment>
In the second embodiment, instead of the illuminance sensor 44, the proximity sensor 46 determines whether the mobile phone 10 is lying on the desk. Since the cellular phone 10 of the second embodiment is substantially the same as the first embodiment, description of the electrical configuration and appearance of the cellular phone 10 and the memory map of the RAM 34 is omitted.

  For example, when the cellular phone 10 is turned downward as shown in FIG. 2B, the power of the proximity sensor 46 is turned on. Then, as shown in FIG. 4A, when the mobile phone 10 is placed on a desk, the distance value obtained based on the output of the proximity sensor 46 is equal to or less than the threshold value. It is determined that 10 is in a face-down state. Therefore, also in the second embodiment, the power of the backlight 40 is turned off when the mobile phone 10 is in the state of FIG. On the other hand, in the state of FIG. 4B, since the distance value is larger than the threshold value, the backlight 40 is dimmed based on the illuminance value.

  As described above, even when the proximity sensor 46 is used, the backlight 40 can be dimmed by appropriately determining the state in which the mobile phone 10 is used, as in the first embodiment.

  Further, power consumption can be suppressed by turning on the power of the proximity sensor 46 only when the proximity sensor 46 needs to be used.

  The processor 24 of the second embodiment performs a plurality of tasks including the backlight control processing of the second embodiment shown in FIG. 7 in parallel under the control of a Linux-based OS such as Android and REX, and other OSs. To process.

  FIG. 7 is a flowchart of the backlight control process of the second embodiment. In this flowchart, the same steps as those in the backlight control process shown in FIG. 6 are assigned the same step numbers, and detailed descriptions thereof are omitted.

  The processor 24 turns on the backlight 40 in step S1, resets the lighting timer in step S3, and adjusts the backlight 40 based on the illuminance value in step S5. In step S7, it is determined whether the mobile phone 10 is in the downward state.

  If “YES” in the step S7, that is, if it is determined to be in a downward state, the power of the proximity sensor 46 is turned on in a step S21, and the process proceeds to a step S25. That is, the power of the proximity sensor 46 is turned on in order to determine whether the surface of the mobile phone 10 is lying on the desk. The processor 24 that executes the process of step S21 functions as a power supply control unit. If “NO” in the step S 7, the power of the proximity sensor 46 is turned off in a step 23.

  In step S25, it is determined whether the distance value is equal to or less than a threshold value. That is, it is determined whether the cellular phone 10 is turned down on a desk or the like and the distance value stored in the distance buffer 336 is equal to or smaller than the threshold value. Note that the processor 24 that executes the process of step S25 functions as a proximity determination unit.

  If “YES” in the step S25, the distance value stored in the distance buffer 336 is equal to or smaller than a threshold value with the mobile phone 10 being placed on a desk as shown in FIG. In step S11, the backlight 40 is turned off, and in step S27, the proximity sensor 46 is turned off. Then, when the process of step S27 ends, the backlight control process ends.

  On the other hand, if “NO” in the step S25, that is, if the distance value stored in the distance buffer 336 is larger than the threshold value, it is determined whether or not the lighting timer expires in a step S13. If “YES” in the step S13, that is, if the lighting timer expires, the process proceeds to a step S11. On the other hand, if “NO” in the step S13, that is, if the lighting timer has not expired, it is determined whether or not the illuminance value has changed in a step S15. If “YES” in the step S15, that is, if the illuminance value changes, the process returns to the step S5. On the other hand, if “NO” in the step S15, that is, if the illuminance value does not change, it is determined whether or not the mobile phone 10 is operated in a step S17. If “NO” in the step S17, that is, if the mobile phone 10 is not operated, the process returns to the step S7. On the other hand, if “YES” in the step S17, that is, if the mobile phone 10 is operated, the process returns to the step S3.

  As described above, in the first embodiment and the second embodiment, it is possible to appropriately determine the state in which the mobile phone 10 is used by using two sensors and control the on / off of the backlight 40. Therefore, the power consumption of the backlight 40 can be suppressed without giving the user a sense of incongruity.

  In the first and second embodiments, the illuminance sensor 44 or the proximity sensor 46 can be used to determine a state where a desk or the like is present near the display surface of the display 30. Therefore, these sensors function as “object detection sensors”.

  In the first embodiment and the second embodiment, the example in which the illuminance sensor 44 and the proximity sensor 46 are both mounted has been described. However, the mobile phone 10 according to another embodiment has only one of them mounted. You may make it do.

  In this embodiment, the acceleration sensor 42 is used to detect the attitude of the mobile phone 10, but in other embodiments, the attitude may be detected using a gyro sensor.

  The communication system of the mobile phone 10 is a CDMA system, but an LTE (Long Term Evolution) system, a W-CDMA system, a GSM system, a TDMA system, an FDMA system, a PHS system, and the like may be employed.

  Further, the plurality of programs used in this embodiment may be stored in the HDD of the data distribution server and distributed to the mobile phone 10 via the network. Further, the storage medium may be sold or distributed in a state where a plurality of programs are stored in a storage medium such as an optical disk such as a CD, DVD, or BD (Blu-ray Disc), a USB memory, or a memory card. When a plurality of programs downloaded through the above-described server or storage medium are installed in a mobile phone having the same configuration as that of this embodiment, the same effect as that of this embodiment can be obtained.

  Furthermore, the present embodiment is not limited to the mobile phone 10 but may be applied to so-called smartphones and PDAs.

  The specific numerical values such as the predetermined time given in the present specification are merely examples, and can be appropriately changed according to the specifications of the product.

DESCRIPTION OF SYMBOLS 10 ... Mobile phone 12 ... Antenna 14 ... Wireless communication circuit 24 ... Processor 26 ... Key input device 34 ... RAM
40 ... Backlight 42 ... Acceleration sensor 44 ... Illuminance sensor 46 ... Proximity sensor

Claims (6)

A portable terminal having a display and a backlight provided in the display, wherein the brightness of the display is adjusted by the backlight;
Posture sensor for detecting posture,
A first determination unit configured to determine whether the mobile terminal is in a downward state based on an output of the attitude sensor;
An object detection sensor that is provided in the vicinity of the display and detects an object existing nearby;
A second determination unit configured to determine whether an object is present near a display surface of the display based on an output of the object detection sensor; and the portable terminal is in a downward state by the first determination unit. And a control unit that turns off the backlight when it is determined by the second determination unit that an object is present near the display surface of the display. . The object detection sensor includes an illuminance sensor that detects ambient illuminance,
2. The mobile phone according to claim 1, wherein the second determination unit includes an illuminance determination unit that determines whether an object is present near a display surface of the display based on the illuminance detected by the illuminance sensor. Terminal. The object detection sensor includes a proximity sensor that detects an adjacent object,
The mobile terminal according to claim 1, wherein the second determination unit includes a proximity determination unit that determines whether an object is present near a display surface of the display based on a detection result of the proximity sensor.   The portable terminal according to claim 3, further comprising a power control unit that turns on the power of the proximity sensor when the first determination unit determines that the downward direction is detected. A display, a backlight provided in the display, an attitude sensor for detecting an attitude, and an object detection sensor provided in the vicinity of the display for detecting an object existing in the vicinity; the brightness of the display is adjusted by the backlight; The handheld processor,
A first determination unit configured to determine whether the mobile terminal is in a downward state based on an output of the attitude sensor;
A second determination unit configured to determine whether an object is present near a display surface of the display based on an output of the object detection sensor; and the portable terminal is in a downward state by the first determination unit. And when the second determination unit determines that an object is present near the display surface of the display, the backlight functions as a control unit that turns off the backlight. Light control program. A display, a backlight provided in the display, an attitude sensor for detecting an attitude, and an object detection sensor provided in the vicinity of the display for detecting an object existing in the vicinity; the brightness of the display is adjusted by the backlight; A backlight control method for a portable terminal,
Based on the output of the attitude sensor, determine whether the mobile terminal is in a downward state,
Based on the output of the object detection sensor, it is determined whether an object exists near the display surface of the display, and it is determined that the portable terminal is in a downward state, and the display surface of the display The backlight control method of turning off the power of the backlight when it is determined that an object is present in the vicinity.

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