JP2014064222A - Mobile terminal, brightness control program, and brightness control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify an effective illuminance detection part from an inclined state of a mobile phone 10 so that the peripheral brightness can be appropriately detected and thereby, controlling brightness of a display 14 appropriately.SOLUTION: A mobile phone 10 comprises a display 14 arranged in a housing 12, and such. On a front face of the housing 12, a window 24 communicating with an illuminance sensor (56) is arranged, and on a rear face of the housing 12, a lens aperture 26 communicating with a camera module (52) is arranged, Also, as the camera module and the illuminance sensor can detect the brightness respectively, each of them function as an illuminance detection part. Further, an inclined state of the mobile terminal 10 is detected by an acceleration sensor (54) arranged inside the housing 12. For example, when a power source of the display 14 is turned on, an effective illumination detection part is specified on the basis of the inclined state. Then, the brightness of the display 14 is controlled on the basis of the brightness detected by the specified illumination detection part.

Description

  The present invention relates to a mobile terminal, a brightness control program, and a brightness control method, and more particularly to a mobile terminal, a brightness control program, and a brightness control method in which a display unit is provided in a housing.

  An example of a portable terminal in which a display unit is provided in a housing is disclosed in Patent Document 1. In the portable terminal device of Patent Document 1, cameras are provided on each of the surface on which the display unit is disposed and the surface on the back side, and each camera functions as an illuminance sensor. For example, when the power is turned on, the front illumination and the back illumination can be obtained from each camera. Based on these illuminances, the optimum luminance value of the display unit is calculated.

The portable terminal disclosed in Patent Document 2 includes a display, an acceleration sensor, an illuminance sensor, and the like, and a table in which illuminance detected when the tilt angle changes within a predetermined range is recorded. In the portable terminal of Patent Literature 2, the ambient brightness can be derived from the tilt angle and the illuminance at that time using the above table. For this reason, the backlight of the display is controlled based on the ambient brightness derived in this way.
JP-A 2005-286523 [H04M 1/00, G02F 1/133, G03B 7/099, G03B 17/18, G09G 3/20] JP 2010-34914 A [H04M 1/00, H04M 1/22, G09G 3/36, G09G 3/20, G09G 3/34]

  However, the portable terminal device of Patent Document 1 cannot obtain correct illuminance in a range exceeding the angle of view of the camera. Therefore, depending on the position of the light source, the correct front illuminance and back illuminance cannot be obtained, and the luminance of the display unit cannot be controlled correctly.

  Further, in the portable terminal of Patent Document 2, when the brightness of the light source is adjusted or the position of the portable terminal is moved, the reference brightness of the table does not match the ambient brightness. In this state, even if a table is used, ambient brightness cannot be derived correctly.

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

  Another object of the present invention is to provide a mobile terminal, a brightness control program, and a brightness control method capable of appropriately controlling the brightness of a display unit.

  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 aspect of this invention is a portable terminal which has a housing | casing and a display part, Comprising: The inclination state detection part which detects the inclination state of a portable terminal, each provided in a different surface of a housing | casing, detects illuminance Based on the inclination state detected by the plurality of illuminance detection units and the inclination state detection unit, a specific unit for identifying an effective illuminance detection unit among the plurality of illuminance detection units, and an illuminance detection unit specified by the specification unit are detected It is a portable terminal provided with the control part which controls the brightness | luminance of a display part based on the illumination intensity to do.

  In the first aspect, the mobile terminal (10: reference numeral exemplifying a corresponding part in the embodiment, hereinafter the same) has, for example, a display unit (14) provided in a flat housing (12). The tilt state detection unit (54) detects the tilt state of the mobile terminal using, for example, an acceleration sensor. Further, when the housing is in a horizontal state, the tilt state detection unit detects 0 degree as the tilt state. Each of the plurality of illuminance detection units (52, 56) is provided on a different surface of the housing and detects the illuminance. The identification unit (30, S3, S7) identifies an effective illuminance detection unit among a plurality of illuminance detection units, for example, based on the current tilt state. A control part (30, S15-S19) controls the brightness | luminance of a display part based on the illumination intensity which the identified illumination intensity detection part detects.

  According to the first aspect, the illuminance can be appropriately detected by specifying an effective illuminance detection unit from the tilted state of the mobile terminal. Thereby, the brightness | luminance of a display part can be controlled appropriately.

  A 2nd aspect depends on a 1st aspect, and a specific | specification part is an effective illumination intensity detection part among several illumination intensity detection parts based on the inclination state detected by the inclination state body detection part for every predetermined time. Is identified.

  In the second aspect, the effective illuminance detection unit is specified based on the tilt state at that time every predetermined time.

  According to the 2nd aspect, since the power supply of an illumination intensity detection part should just be turned on only when predetermined time passes, the electric power consumed in order to detect illumination intensity can be suppressed.

  A 3rd aspect is dependent on a 1st aspect or a 2nd aspect, and is further provided with the backlight provided in a display part, and a control part is based on the illumination intensity which the illumination intensity detection part specified by the specific part detects. Control the brightness of the backlight.

  In the third aspect, the display unit is an LCD monitor, for example, and is provided with a backlight (50). The control unit controls the luminance of the display unit by controlling the backlight.

  A fourth aspect is dependent on any one of the first to third aspects, wherein the plurality of illuminance detection units include a first illuminance detection unit and a second illuminance detection unit, and the first illuminance detection unit is a housing. The second illuminance detection unit is provided on the back surface of the housing.

  In the fourth aspect, the first illuminance detector (56) is provided on the front surface of the housing, and the second illuminance detector (52) is provided on the back surface of the housing.

  A 5th aspect depends on a 4th aspect and a display part is provided in the surface.

  In the fifth aspect, the display unit is provided on the same surface as the first illuminance detection unit.

  According to the fourth aspect and the fifth aspect, the luminance of the display unit can be appropriately controlled by appropriately using the two illuminance detection units.

  A 6th aspect depends on a 4th aspect or a 5th aspect, and a some illumination intensity detection part further contains the 3rd illumination intensity detection part, and a 3rd illumination intensity detection part is provided in the side surface of a housing | casing.

  In the sixth aspect, the third illuminance detection unit is provided on the upper side surface, for example.

  According to the sixth aspect, it is possible to appropriately control the luminance of the display unit by appropriately using the three illuminance detection units.

  A seventh aspect is dependent on any one of the first to sixth aspects, and the plurality of illuminance detection units include an illuminance sensor (56).

  An eighth aspect is dependent on any one of the first to seventh aspects, and the plurality of illuminance detection units include a camera module.

  In the eighth aspect, the illuminance is calculated based on the image data output from the camera module (52).

  The ninth aspect includes a housing (12), a display unit (14), a tilt state detection unit (54) that detects a tilt state, and a plurality of illuminance detection units that are provided on different surfaces of the housing and detect illuminance. Identifying the effective illuminance detection unit among the plurality of illuminance detection units based on the tilt state detected by the tilt state detection unit, the processor (30) of the portable terminal (10) having (52, 56) This is a luminance control program that functions as a control unit (S15-S19) that controls the luminance of the display unit based on the illuminance detected by the illuminance detection unit specified by the unit (S3, S7) and the specifying unit.

  Also in the ninth aspect, as in the first aspect, the illuminance can be appropriately detected by specifying an effective illuminance detection unit from the tilted state of the mobile terminal. Thereby, the brightness | luminance of a display part can be controlled appropriately.

  The tenth aspect includes a housing (12), a display unit (14), a tilt state detection unit (54) that detects a tilt state, and a plurality of illuminance detection units that are provided on different surfaces of the housing and detect illuminance. (52, 56) The brightness control method of the portable terminal (10), wherein an effective illuminance detection unit is specified among a plurality of illuminance detection units based on the tilt state detected by the tilt state detection unit. (S3, S7) and the luminance control method in which the luminance of the display unit is controlled based on the illuminance detected by the specified illuminance detection unit (S15-S19).

  In the tenth aspect, as in the first aspect, the illuminance can be appropriately detected by specifying an effective illuminance detection unit from the tilted state of the mobile terminal. Thereby, the brightness | luminance of a display part can be controlled appropriately.

  According to the present invention, the luminance of the display unit can be appropriately controlled.

  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 external view showing a mobile phone according to an embodiment of the present invention. FIG. 2 is an illustrative view showing an electrical configuration of the mobile phone shown in FIG. FIG. 3 is an illustrative view showing the characteristics of the illuminance sensor shown in FIG. 2, FIG. 3 (A) shows the sensitivity characteristics of the illuminance sensor, and FIG. 3 (B) shows the output characteristics of the illuminance sensor. 4 is an illustrative view showing one example of a detection range of a camera module and an illuminance sensor in the mobile phone shown in FIG. FIG. 5 is an illustrative view showing one example of an angle range in which an effective illuminance detection unit is specified in the mobile phone shown in FIG. FIG. 6 is an illustrative view showing one example of a memory map of the RAM shown in FIG. FIG. 7 is a flowchart showing an example of luminance control processing of the processor shown in FIG. FIG. 8 is an external view showing a mobile phone according to another embodiment of the present invention. FIG. 9 is an illustrative view showing one example of a detection range of a camera module and an illuminance sensor in the mobile phone shown in FIG. FIG. 10 is an illustrative view showing one example of an angle range in which an effective illuminance detection unit is specified in the mobile phone shown in FIG. FIG. 11 is an external view showing a mobile phone according to another embodiment of the present invention.

<First embodiment>
Referring to FIGS. 1A and 1B, a mobile phone 10 according to an embodiment of the present invention is a smartphone as an example, and includes a vertically long casing 12. However, it should be pointed out in advance that the present invention can be applied to any portable terminal such as a so-called feature phone, a tablet terminal, or a PDA.

  On the surface (main surface) of the housing 12, a display 14 including an LCD monitor that functions as a display unit is provided. On the display 14, a touch panel 16 which is a kind of pointing device is provided. Therefore, in the cellular phone 10 of this embodiment, most of the input operations except those by hard key operations described later are performed through the touch panel 16.

  A speaker 18 is built in the main surface at one longitudinal end of the housing 12, and a microphone 20 is built in the main surface at the other vertical end. Further, on the surface (main surface) of the housing 12, a window 24 leading to the illuminance sensor 56 (see FIG. 2) is provided on the right side of the speaker 18.

  On the surface of the housing 12, hard keys 22 that constitute input operation means together with the touch panel 16 are provided. In this embodiment, the hard keys 22 include a call key 22a, an end key 22b, and a menu key 22c.

  A lens opening 26 that communicates with the camera module 52 (see FIG. 2) is provided at one longitudinal end of the back surface (other surface) of the housing 12.

  For example, the user can input a telephone number by touching the dial key displayed on the display 14 with the touch panel 16, and can start a voice call by operating the call key 22a. The user can end the voice call by operating the call end key 22b. The user can turn on / off the power of the mobile phone 10 by pressing and holding the end call key 22b.

  Further, if the menu key 22c is operated, a menu screen is displayed on the display 14, and a desired operation can be performed by touching the touch panel 16 with respect to the soft keys and menu icons displayed on the display 14 in that state. The function can be executed.

  Further, as will be described in detail later, when the camera function is executed, the camera module 52 is activated and a preview image (through image) corresponding to the object scene is displayed on the display 14. Then, the user can take a picture of the subject by performing a photographing operation with the back surface on which the lens opening 24 is provided facing the subject.

  Referring to FIG. 2, the mobile phone 10 of the embodiment shown in FIG. 1 includes a processor 30 called a computer or a CPU. The processor 30 includes a wireless communication circuit 32, an A / D converter 36, a D / A converter 38, an input device 40, a display driver 42, a flash memory 44, a RAM 46, a touch panel control circuit 48, a backlight 50, and a camera module 52. The acceleration sensor 54 and the illuminance sensor 56 are connected.

  The processor 30 controls the entire mobile phone 10. In the RAM 46 functioning as a storage unit, all or a part of a program preset in the flash memory 44 is expanded when used. The processor 30 operates according to a program on the RAM 46. The RAM 46 is further used as a working area or a buffer area for the processor 30.

  The input device 40 includes the hard key 22 shown in FIG. 1 and constitutes an operation unit or an input unit. Information on the hard key operated by the user (key data) is input to the processor 30.

  The wireless communication circuit 32 is a circuit for transmitting and receiving radio waves for voice calls and mails through the antenna 34. In the embodiment, the wireless communication circuit 32 is a circuit for performing wireless communication by the CDMA method. For example, when the user operates the input device 40 to instruct a telephone call (calling), the wireless communication circuit 32 performs a telephone call processing under the instruction of the processor 30 and sends a telephone call signal via the antenna 34. Output. The telephone call signal is transmitted to the other party's telephone through the base station and the communication network. When an incoming call process is performed at the other party's telephone, a communicable state is established, and the processor 30 executes a call process.

  The microphone 20 shown in FIG. 1 is connected to the A / D converter 36, and the audio signal from the microphone 20 is input to the processor 30 as digital audio data through the A / D converter 36. The speaker 18 is connected to the D / A converter 38. The D / A converter 38 converts digital audio data into an audio signal and supplies the audio signal to the speaker 18 through an amplifier. Therefore, the sound data is output from the speaker 18.

  A display 14 shown in FIG. 1 is connected to the display driver 42. Therefore, the display 14 displays a video or image according to the video or image data output from the processor 30. That is, the display driver 42 controls display on the display 14 connected to the display driver 42 under the instruction of the processor 30. The display driver 42 includes a video memory that temporarily stores image data to be displayed. The display 14 is provided with a backlight 50 using, for example, an LED as a light source. The processor 30 controls the brightness of the backlight 50 and lighting / extinguishing based on ambient brightness (illuminance). That is, the processor 30 controls the brightness of the display 14 by controlling the backlight 50.

  The touch panel 16 shown in FIG. 1 is connected to the touch panel control circuit 48. The touch panel control circuit 48 applies necessary voltage and the like to the touch panel 16 and also displays a touch start signal indicating the start of touch by the user on the touch panel 16, an end signal indicating the end of touch by the user, and a touch position touched by the user. The indicated coordinate data is input to the processor 30. Therefore, the processor 30 can determine which icon or key the user touched at that time based on the coordinate data. Note that the detection method of the touch panel 16 may employ a surface-type capacitance method, or may employ a resistance film method, an ultrasonic method, an infrared method, an electromagnetic induction method, or the like. The touch operation is not limited to the user's finger, and may be performed with a stylus pen or the like.

  The camera module 52 includes a control circuit, a lens, an image sensor, and the like. When an operation for executing the camera function is performed, the processor 30 activates the control circuit and the image sensor. When image data based on the signal output from the image sensor is input to the processor 30, a preview image corresponding to the subject is displayed on the display 14.

  The processor 30 detects the brightness around the mobile phone 10 based on the image data output from the image sensor. The range (detection range) in which the camera module 52 can detect the illuminance substantially matches the angle of view of the camera module 52.

  The acceleration sensor 54 is a semiconductor triaxial acceleration sensor. The acceleration sensor 54 outputs triaxial (X, Y, Z) acceleration data for the mobile phone 10 to the processor 30. The processor 30 determines the movement of the mobile phone 10 by detecting a change in the triaxial acceleration data. Further, the processor 30 can calculate the tilt state (angle) of the mobile phone 10 (housing 12) based on the gravitational acceleration detected by the acceleration sensor 54. For example, when the attitude of the mobile phone 10 changes, the processor 30 sets the display direction of the display 14 based on the tilt state at that time. The acceleration sensor 54 may be referred to as a tilt state detection unit.

  The illuminance sensor 56 includes photodiodes integrated in an array. Each photodiode changes its output when it receives light. The processor 30 detects the brightness around the mobile phone 10 based on the change in the output of each photodiode. In other embodiments, a phototransistor may be used instead of the photodiode.

  In the mobile phone 10 described above, ambient brightness can be detected by the camera module 52 and the illuminance sensor 56. Therefore, the camera module 52 and the illuminance sensor 56 may be referred to as an illuminance detection unit. In particular, the illuminance sensor 56 may be referred to as a first illuminance detector, and the camera module 56 may be referred to as a second illuminance detector.

3A shows the sensitivity characteristic of the illuminance sensor 56, and FIG. 3B shows the output characteristic of the illuminance sensor 56. When the sensitivity level is 0.6 or more as an effective measurement range, when light is applied from directly above the illuminance sensor 56 with an effective measurement range of ± 20 degrees, the sensitivity characteristic of the illuminance sensor 56 is shown in FIG. ) As shown.

  However, there is actually not much environment where the light source is just above, and in the case of indoors, a plurality of light sources (for example, fluorescent lamps) are generally present on the ceiling. Therefore, the output characteristic of the illuminance sensor 56 in a state where the mobile phone 10 is placed indoors horizontally so that the surface of the mobile phone 10 is up is as shown in FIG. That is, when a plurality of light sources are above, the effective detection range of the illuminance sensor 56 is about ± 30 degrees.

  When the position of the light source deviates from the detection range, it becomes difficult for the illuminance sensor 56 to receive the illuminated light, and the measured value in this case is far from the actual brightness.

  FIG. 4 is an illustrative view showing detection ranges of the camera module 52 and the illuminance sensor 56 with respect to the mobile phone 10. Referring to FIG. 4, the detection range of illuminance sensor 56 on the surface of mobile phone 10 is ± 30 degrees centering on an axis perpendicular to the surface and passing through the center of illuminance sensor 56 (opening 24). On the other hand, the detection range of the camera module 52 on the back surface of the mobile phone 10 is ± 30 degrees centering on an axis perpendicular to the back surface and passing through the center of the image sensor (lens opening 26) of the camera module 52.

  FIG. 5 is an illustrative view showing an angle range AR for specifying an effective illuminance detection unit. In FIG. 5, as described above, a state where the surface of the mobile phone 10 (illuminance sensor 56) is placed in a horizontal state so as to face upward is defined as an inclined state of 0 degree. In this state, since the central axis of the detection range of the illuminance sensor 56 faces directly above, the detection range of the illuminance sensor 56 is ± 30 degrees, so the range of ± 30 degrees when the tilt state is 0 degree, that is, 330 degrees. The first angle range AR1 between 360 degrees and 1 degree to 30 degrees corresponds to the detection range of the illuminance sensor 56.

  On the other hand, when the mobile phone 10 is placed in a horizontal state so that the back surface (camera module 52) faces upward, the inclined state becomes 180 degrees. Therefore, the range of ± 30 degrees when the tilt state is 180 degrees, that is, the second angle range AR2 of 150 degrees to 210 degrees corresponds to the detection range of the camera module 52.

  If the tilt state is included in the first angle range AR1, the illuminance sensor 56 is specified as an effective illuminance detection unit. If the tilt state is included in the second angle range AR2, the camera module 52 is identified as an effective illuminance detection unit. When an effective illuminance detection unit is specified, ambient brightness can be appropriately detected. If the tilt state is not included in the first angle range AR1 or the second angle range AR2, the illuminance is complementarily calculated based on the tilt state at that time.

  Thus, by specifying an effective illuminance detection unit from the tilted state of the mobile phone 10, the illuminance can be detected appropriately. Thereby, the brightness | luminance of the display 14 can be controlled appropriately.

  Moreover, the power consumption of the display 14 can be suppressed by appropriately controlling the luminance of the display 14.

  Particularly in the first embodiment, the luminance of the display 14 can be appropriately controlled by appropriately using the camera module 52 and the illuminance sensor 56.

  Also, the effective illuminance detection unit is specified every predetermined time (for example, several seconds to 10 seconds). Therefore, the power sources of the camera module 52 and the illuminance sensor 56 need only be turned on when a predetermined time has elapsed. Thereby, the electric power consumed in order to detect illumination intensity can be suppressed.

  However, the predetermined time for detecting effective illuminance may be changed based on the state of the mobile phone 10. For example, when the mobile phone 10 is not moving, that is, when the output of the acceleration sensor 54 is not changed, it is unlikely that the ambient brightness will change, so that effective illuminance is detected every 10 seconds. A predetermined time is set. Further, when the mobile phone 10 is moving, that is, when the output of the acceleration sensor 54 is changing, the ambient brightness is likely to change, so that effective illuminance is detected every 3 seconds. A predetermined time is set. The predetermined time may be changed based on the current illuminance.

  Although the features of the embodiment have been outlined above, a detailed description will be given below using the memory map shown in FIG. 6 and the flowchart shown in FIG.

  Referring to FIG. 6, program storage area 302 and data storage area 304 are formed in RAM 46 shown in FIG. As described above, the program storage area 302 is an area for reading and storing (developing) part or all of the program data set in advance in the flash memory 44 (FIG. 2).

  The program storage area 302 stores a luminance control program 310 for controlling the luminance of the display 14 and an illuminance interpolation program 312 for performing an illuminance interpolation calculation when the tilt state is not included in the angle range AR. . Note that the program storage area 302 also includes programs for executing a telephone function, a mail function, an alarm function, and the like.

  Subsequently, in the data storage area 304 of the RAM 46, a touch buffer 330, an acceleration buffer 332, an illuminance buffer 334, a tilt state buffer 336, a backlight flag 338, a luminance counter 340, and the like are provided.

  The touch buffer 330 stores touch coordinate data output from the touch panel control circuit 48. In the acceleration buffer 332, the output of the acceleration sensor 54 is temporarily stored. The illuminance buffer 334 temporarily stores the illuminance detected by the camera module 52, the illuminance detected by the illuminance sensor 56, or the illuminance obtained by the interpolation calculation. The tilt state buffer 336 temporarily stores the tilt state calculated based on the acceleration stored in the acceleration buffer 332, that is, the angle.

  The backlight flag 338 is a flag for determining whether the power of the backlight 50 is on. For example, the backlight flag 338 is composed of a 1-bit register. When the backlight flag 338 is turned on (established), a data value “1” is set in the register. On the other hand, when the backlight flag 338 is turned off (not established), a data value “0” is set in the register.

  The luminance counter 340 is a counter for detecting effective illuminance every predetermined time. When the luminance counter 340 is initialized, it starts counting and expires when a predetermined time elapses. Therefore, the luminance counter 340 is sometimes called a luminance timer.

  The data storage area 304 stores image data displayed in a standby state, character string data, and the like, and is provided with counters and flags necessary for the operation of the mobile phone 10.

  The processor 30 processes a plurality of tasks in parallel, including a brightness control process shown in FIG. 7 under the control of a Linux (registered trademark) -based OS such as Android (registered trademark) or REX, and other OSs. To do.

  The brightness control process is started, for example, when the power of the backlight 50 is turned on, that is, when the backlight flag 338 is turned on. In step S1, the processor 30 calculates an inclined state. That is, the tilt state (angle) of the mobile phone 10 is calculated based on the acceleration stored in the acceleration buffer 332. Further, the calculated tilt state is stored in the tilt state buffer 336.

  Subsequently, in step S3, the processor 30 determines whether or not the first angle range AR1. For example, the processor 30 determines whether the calculated tilt state is included in the first angle range AR1 of 330 degrees to 360 degrees and 1 degree to 30 degrees. If “YES” in the step S3, for example, if the tilt state is 350 degrees and is included in the first angle range AR1, the processor 30 detects the illuminance by the illuminance sensor 56 in a step S5, and proceeds to the step S13. .

  If “NO” in the step S3, that is, if the inclined state is not included in the first angle range AR1, the processor 30 determines whether or not the second angle range AR2 in a step S7. For example, it is determined whether the calculated inclination state is included in the second angle range AR2 of 150 to 210 degrees. If “YES” in the step S7, for example, if the tilt state is 180 degrees and is included in the second angle range AR2, the processor 30 detects the illuminance by the camera module 52 in a step S9, and proceeds to the step S13. . That is, the processor 30 calculates the illuminance based on the image data output from the camera module 52.

  On the other hand, if “NO” in the step S7, that is, if the calculated inclination state is not included in the two angle ranges AR, the processor 30 executes an illuminance interpolation process in a step S11. That is, since it is not in a state where an effective illuminance detection unit can be specified, the illuminance is calculated by performing a complementary operation on the illuminance detected by the camera module 52 and the illuminance sensor 56.

  The processor 30 that executes the process of step S3 or step S7 functions as a specifying unit.

  Subsequently, in step S13, the illuminance is stored in the illuminance buffer 334. That is, the illuminance obtained by any of the camera module 52, the illuminance sensor 56, and the interpolation calculation is stored in the illuminance buffer 334.

  Subsequently, in step S15, it is determined whether or not the illuminance has changed. For example, it is determined whether the absolute value of the difference between the previous illuminance stored in the illuminance buffer 334 and the newly stored illuminance is greater than or equal to the first threshold. If “YES” in the step S15, that is, if the illuminance changes, the processor 30 determines whether or not the luminance needs to be changed in a step S17. That is, it is determined whether the luminance of the display 14 needs to be changed. Specifically, the processor 30 determines whether the absolute value of the difference between the previous illuminance and the newly stored illuminance is above the second threshold (> first threshold). If “YES” in the step S17, that is, if it is necessary to change the luminance, the processor 30 changes the luminance of the display 14 in a step S19, and then proceeds to a step S21. That is, the brightness of the backlight 50 is set based on the illuminance stored in the brightness buffer 334. If “NO” in the step S17, that is, if it is not necessary to change the luminance, the processor 30 proceeds to the step S21.

  Note that the processor 30 that executes the processes of steps S15 to S19 functions as a control unit.

  If “NO” in the step S15, that is, if the illuminance has not changed, the processor 30 initializes a luminance timer in a step S21. That is, the brightness counter 340 is initialized. At this time, the processor 30 sets a time at which the luminance counter expires, that is, a predetermined time, based on the change in the output of the acceleration sensor 54.

  Subsequently, in step S23, the processor 30 determines whether or not the luminance timer has expired. That is, it is determined whether a predetermined time has elapsed since effective illuminance was detected. If “YES” in the step S23, that is, if a predetermined time has elapsed, the processor 30 returns to the step S1.

  If “NO” in the step S23, that is, if the predetermined time has not elapsed, the processor 30 determines whether or not the backlight 50 is turned off in a step S25. For example, it is determined that the power of the backlight 50 is turned off and the backlight flag 338 is turned off. If “NO” in the step S25, that is, if the power of the backlight 50 is turned on, the processor 30 returns to the step S23.

  If “YES” in the step S25, for example, when the power of the backlight 50 is turned off for power saving, the processor 30 ends the luminance control process.

<Second embodiment>
In the second embodiment, in addition to the camera module 52 and the illuminance sensor 56, a new illuminance sensor (third illuminance detection unit) is further provided. The other configuration of the mobile phone 10 is the same as that of the first embodiment except that a new illuminance sensor is added, and thus detailed description such as drawings showing the electrical configuration of the mobile phone is omitted. Furthermore, since the sensitivity range of the new illuminance sensor is substantially the same as that of the illuminance sensor 56, the drawings showing the sensitivity characteristics and the output characteristics are also omitted.

  Referring to FIGS. 8A and 8B, the housing 12 of the mobile phone 10 according to the second embodiment has a display 14, a touch panel 16, a speaker 18, a microphone 20, and hard keys as in the first embodiment. 22, a window 24 and a lens opening 26 are provided.

  Referring to FIG. 8C, a window 28 that leads to a new illuminance sensor is provided on the upper side surface of the housing 12.

  FIG. 9 is an illustrative view showing detection ranges of the camera module 52, the illuminance sensor 56, and a new illuminance sensor for the mobile phone 10. Referring to FIG. 9, the detection ranges of the camera module 52 and the illuminance sensor 56 are substantially the same as in the first embodiment. In addition, the detection range of the new illuminance sensor on the upper side surface of the mobile phone 10 is ± 30 degrees about the axis that is perpendicular to the upper side surface and passes through the center of the new illuminance sensor.

  FIG. 10 is an illustrative view showing an angle range AR for specifying an effective illuminance detection unit in the second embodiment. Referring to FIG. 10, the range of ± 30 degrees when the tilt state is 0 degrees, that is, the first angle range AR1 of 330 degrees to 330 degrees and 1 degree to 30 degrees corresponds to the detection range of the illuminance sensor 56. Further, the range of ± 30 degrees when the tilt state is 180 degrees, that is, the second angle range AR2 of 150 degrees to 210 degrees corresponds to the detection range of the camera module 52.

  When the mobile phone 10 is placed so that the upper side surface (new illuminance sensor) faces upward, the inclined state becomes 90 degrees. Therefore, the range of ± 30 degrees when the tilt state is 90 degrees, that is, the third angle range AR3 of 60 degrees to 120 degrees corresponds to the detection range of the new illuminance sensor. Therefore, if the tilt state is included in the third angle range AR3, a new illuminance sensor is specified as effective illuminance detection means.

  As described above, in the second embodiment, the luminance of the display 14 can be appropriately controlled by appropriately using the camera module 52 and the two illuminance sensors.

  In the brightness control process of the second embodiment, after the process of step S7 shown in FIG. 7, there are a determination step for determining whether or not the angle range is the third angle range, and a process step for detecting illuminance by a new illuminance sensor. Added. If “YES” is determined in the determination step, the illuminance is detected by the new illuminance sensor in the processing step, and then the processor 30 proceeds to step S13. On the other hand, if “NO” is determined in the determination step, the processor 30 proceeds to step S11.

<Third embodiment>
In the third embodiment, a new illuminance sensor is provided on the right side surface. The configuration of the mobile phone 10 is substantially the same as that of the first embodiment and the second embodiment, and detailed description thereof is omitted.

  Referring to FIGS. 11A and 11B, the housing 12 of the mobile phone 10 of the third embodiment includes a display 14, a touch panel 16, a speaker 18, and the like, as in the first and second embodiments. A microphone 20, a hard key 22, a window 24, and a lens opening 26 are provided.

  In addition, referring to FIG. 11C, a window 28 that leads to a new illuminance sensor is provided on the right side surface of housing 12. Therefore, in the third embodiment, the ambient brightness can be detected appropriately even if the mobile phone 10 is held sideways.

  The first embodiment to the third embodiment can be arbitrarily combined, and a specific combination can be easily imagined, and thus detailed description thereof is omitted.

  Further, the new illuminance sensor may be provided on the left side surface and the lower side surface. Further, a new illuminance sensor may be added.

  When the camera module 52 and the illuminance sensor 56 are provided on the same surface, the use of the illuminance sensor 56 may be preferentially used from the viewpoint of power saving.

  In other embodiments, all the illuminance detection units may be the illuminance sensor 56 or the camera module 52.

  In addition, when the detection ranges of the two illuminance detection units overlap and the inclined state is included in the overlapping range, the illuminance may be obtained using the outputs of the two illuminance detection units, and priority is given. The illuminance detection unit may be determined in advance.

  Further, the detection range of the illuminance sensor 56 or the camera module 52 may be arbitrarily adjusted using a light guide member or the like.

  Further, instead of the acceleration sensor 52, the tilt state of the mobile phone 10 may be detected by a gyro sensor.

  In another embodiment, the display 14 may be an organic EL monitor. In this case, the backlight 50 is omitted. Further, when the luminance of the organic EL monitor is controlled as in the present embodiment, a specific effect of extending the component life of the organic EL monitor can be obtained.

  In other embodiments, the brightness control process may be executed when an application is executed.

  The program 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, a USB memory, or a memory card. When the program downloaded through the above-described server or storage medium is installed in a portable terminal having the same configuration as that of this embodiment, the same effect as that of this embodiment can be obtained.

  The specific numerical values given in this specification are merely examples, and can be appropriately changed according to a change in product specifications.

DESCRIPTION OF SYMBOLS 10 ... Mobile phone 12 ... Case 14 ... Display 30 ... Processor 44 ... Flash memory 46 ... RAM
50 ... Backlight 52 ... Camera module 54 ... Acceleration sensor 56 ... Illuminance sensor

Claims (10)

A portable terminal having a housing and a display unit,
An inclination state detection unit for detecting an inclination state of the housing;
A plurality of illuminance detection units that are provided on different surfaces of the housing and detect illuminance,
Based on the tilt state detected by the tilt state detection unit, the specifying unit that identifies an effective illuminance detection unit among the plurality of illuminance detection units, and the illuminance detected by the illuminance detection unit specified by the specifying unit A mobile terminal comprising a control unit for controlling the luminance of the display unit based on the control unit.   The mobile terminal according to claim 1, wherein the specifying unit specifies an effective illuminance detection unit among the plurality of illuminance detection units based on an inclination state detected by the inclination state body detection unit every predetermined time. . Further comprising a backlight provided in the display unit,
The mobile terminal according to claim 1, wherein the control unit controls the luminance of the backlight based on the illuminance detected by the illuminance detection unit specified by the specifying unit. The plurality of illuminance detection units include a first illuminance detection unit and a second illuminance detection unit,
4. The mobile terminal according to claim 1, wherein the first illuminance detection unit is provided on a front surface of the casing, and the second illuminance detection unit is provided on a back surface of the casing.   The mobile terminal according to claim 4, wherein the display unit is provided on the surface. The plurality of illuminance detection units further include a third illuminance detection unit,
The mobile terminal according to claim 4, wherein the third illuminance detection unit is provided on a side surface of the housing.   The mobile terminal according to claim 1, wherein the plurality of illuminance detection units include an illuminance sensor.   The mobile terminal according to claim 1, wherein the plurality of illuminance detection units include a camera module. A processor of a portable terminal having a housing, a display unit, a tilt state detection unit that detects a tilt state of the housing, and a plurality of illuminance detection units that detect illuminance provided on different surfaces of the housing,
Based on the tilt state detected by the tilt state detection unit, the specifying unit that identifies an effective illuminance detection unit among the plurality of illuminance detection units, and the illuminance detected by the illuminance detection unit specified by the specifying unit A brightness control program that functions as a control unit that controls the brightness of the display unit based on the program. A brightness control method for a mobile terminal, comprising: a housing, a display unit, an inclination state detection unit that detects an inclination state of the housing, and a plurality of illuminance detection units that detect illuminance provided on different surfaces of the housing There,
Based on the tilt state detected by the tilt state detection unit, an effective illuminance detection unit is identified among the plurality of illuminance detection units, and the display unit is based on the illuminance detected by the identified illuminance detection unit A luminance control method for controlling the luminance of the image.

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