JP5381866B2 - Portable terminal device, power consumption reduction method and program for portable terminal device - Google Patents

Description

  The present invention relates to a mobile terminal device, a method for reducing power consumption of the mobile terminal device, and a program.

  In a mobile terminal device such as a mobile phone, a liquid crystal display including a backlight is widely used for screen display. Techniques for automatically changing the display form of the liquid crystal display for the purpose of improving user convenience are known (for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a technique for automatically changing the luminance of a liquid crystal display so that a user can easily see the external luminance.

  Patent Document 2 discloses a technique for causing a backlight to develop a predetermined color according to a user's specific operation on a schedule function or calendar function screen so that the user can intuitively understand the information. ing.

JP 2000-310983 A JP 2001-86217 A

  As mobile phones become widespread, the number of users who utilize the accompanying electronic mail (hereinafter, also simply referred to as mail) function has increased, and the frequency of use of the mail function has increased. However, the screen of the mobile phone is always displayed during the creation of the mail, and the backlight of the liquid crystal screen remains on while the characters are being input. For this reason, there is a problem that a user who frequently creates e-mails has a short battery life, that is, a battery charging or replacement interval is shortened.

  It is already known that the brightness of the backlight of the screen is manually changed step by step in order to extend the battery charging or replacement interval as much as possible, that is, to make the battery last longer. In such a mobile phone, the battery consumption is reduced by setting the backlight of the screen to be dark. However, in such a setting, there is a drawback in that visibility is lacking by dimming the backlight of the screen, such as when a character is input such as creating an e-mail when the surroundings are bright.

  In recent mobile phones, the background color of the screen can be selected according to the user's preference, and the background color is reflected on the screen when creating the mail. In the case of a mobile phone equipped with such a function, if the background color is light, a large amount of current is consumed for screen display. If the background color is dark, the consumption for screen display is higher than that for light colors. Battery consumption at the time of mail creation differs depending on the background color, such as low current. Therefore, for a user who has selected a background color that consumes a large amount of battery, the battery life is worse than when a background color that consumes the least amount of battery is selected.

  The present invention has been made in view of the above problems, and provides a portable terminal device capable of extending the battery life even when the e-mail function is frequently used, a power consumption reduction method for the portable terminal device, and a program. For the purpose.

In order to achieve the above object, a mobile terminal device according to the first aspect of the present invention provides:
Display means comprising a liquid crystal panel for displaying an image and a backlight for irradiating the liquid crystal panel with light from the back;
A battery for supplying power to the display means;
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
Backlight adjustment means for adjusting the brightness of the backlight corresponding to the background image displayed on the liquid crystal panel;
When the liquid crystal panel displays the predetermined image, a background image to be displayed is selected from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized . A background image setting means for changing the background image when the luminance is equal to or higher than a predetermined reference value ;
It is characterized by that.

In order to achieve the above object, a method for reducing power consumption of a mobile terminal device according to a second aspect of the present invention includes:
A method for reducing power consumption of a portable terminal device, comprising: a display unit that includes a liquid crystal panel that displays an image; a backlight that irradiates light to the liquid crystal panel from the back; and a battery that supplies power to the display unit. ,
Prepared in advance so that the power consumption of the backlight is minimized when displaying a predetermined image including a part of a background image and information for a predetermined operation by the user on the liquid crystal panel. Selecting a background image to be displayed from a group of a plurality of types of background images, and changing the background image when the luminance of the backlight is equal to or higher than a predetermined reference value;
It is characterized by that.

In order to achieve the above object, a program according to the third aspect of the present invention provides:
A computer for controlling a mobile terminal device, comprising: a display means comprising a liquid crystal panel for displaying an image; and a backlight for irradiating the liquid crystal panel with light from the back; and a battery for supplying power to the display means.
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
When the liquid crystal panel displays the predetermined image, a background image to be displayed is selected from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized . Background image setting means for changing the background image when the luminance is equal to or higher than a predetermined reference value ;
It is made to function as.

  According to the present invention, in the mobile terminal device, it is possible to make the battery last longer even when the electronic mail function is frequently used.

It is a block diagram which shows the functional structure of the portable terminal device which concerns on 1st Embodiment of this invention. It is a block diagram which shows the more concrete structure of the portable terminal device of FIG. It is a figure which shows the example of a standby screen and a mail preparation screen. It is a figure which shows the standby screen and mail preparation screen of 1st Embodiment. It is a flowchart which shows the screen calling process of 1st Embodiment. It is a flowchart which shows the screen calling process of 2nd Embodiment of this invention. It is a figure which shows the pop-up screen which inquires the change of a background color. It is a flowchart which shows the screen calling process in 3rd Embodiment of this invention. It is a flowchart which shows the background color setting process in 4th Embodiment of this invention. It is a figure which shows the example of a display of a background color setting screen. It is a block diagram which shows the structure of the portable terminal device which concerns on 5th Embodiment of this invention. It is a flowchart which shows the screen calling process of 5th Embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following example, a mobile terminal device as a so-called mobile phone will be described.

(First embodiment)
As shown in FIG. 1, the mobile terminal device 1 according to this embodiment includes a display unit 51, an e-mail processing unit 52, a backlight adjustment unit 53, a background image setting unit 54, and a battery 40. ing.

  In this embodiment, the display means 51 is configured as a liquid crystal display, and includes a liquid crystal panel 31 and a backlight 32. The liquid crystal panel 31 displays various information such as characters and figures in the screen area. In the following description of the operation, the screen area of the liquid crystal panel 31 is shown in each drawing. The backlight 32 emits light of a predetermined color and brightness from the rear of the screen area of the liquid crystal panel 31.

  The e-mail processing unit 52 processes the entire e-mail function of the mobile terminal device 1, and in this embodiment, has a function for displaying the e-mail creation screen on the display unit 51 in particular.

  The backlight adjustment unit 53 adjusts the luminance of the backlight 32 according to the image displayed on the liquid crystal panel 31 of the display unit 51.

  The background image setting unit 54 selects an image that consumes less power when creating an e-mail from a group of a plurality of types of background images set in advance, and causes the display unit 51 to display the selected image. This operation will be described later.

  The battery 40 is a secondary battery that supplies power to each of the above-described means. The specific configuration of the battery 40 may be arbitrary, and may be a primary battery.

  FIG. 2 is a block diagram showing a more specific configuration of the mobile terminal device 1 according to the present embodiment. As shown in FIG. 2, the mobile terminal device 1 includes an antenna 11, a radio unit 12, a memory 13, a voice / audio signal processing unit 14, an output device 15, a microphone 16, a control unit 17, and an operation. A unit 18, a display unit 19, and a battery 40 are provided.

  The wireless unit 12 is connected to the antenna 11 and performs transmission / reception processing of a wireless signal through the antenna 11.

  The audio / audio signal processing unit 14 is connected to the output device 15 and the microphone 16, and performs D / A (digital / analog) conversion on audio and audio signals received via the antenna 11, the radio unit 12, and the control unit 17. Then, it is output from the output device 15 as voice or music data. The audio / audio signal processing unit 14 performs A / D (analog / digital) conversion on the audio input from the microphone 16 and transmits the converted audio to the other party via the control unit 17, the radio unit 12, and the antenna 11.

  The output device 15 is an apparatus that outputs sound in the present embodiment. The specific configuration of the output device 15 is arbitrary, and may be any of various forms such as a receiver, a speaker, an earphone, and an external hands-free.

  The operation unit 18 includes a plurality of keys and the like for the user to input a telephone number and the like, select each function, and the like.

  The display unit 19 is configured as a liquid crystal display corresponding to the display unit 51 illustrated in FIG. 1, and includes a liquid crystal panel 31 and a backlight 32.

  The control unit 17 includes a CPU (Central Processing Unit) 20. The control unit 17 is connected to the radio unit 12, the memory 13, the audio signal processing unit 14, the operation unit 18, the display unit 19, and the battery 40. The control unit 17 controls each of these units. I do. In addition, the control unit 17 monitors the operation unit 18, detects and determines a user operation, performs processing based on the operation, and controls the display unit 19 to perform various displays. For these controls, the CPU 20 of the control unit 17 executes a program stored in the memory 13.

  The memory 13 is a storage device that stores a program executed by the control unit 17 and stores data set by the user.

  Hereinafter, the operation of the mobile terminal device 1 having the above-described configuration will be described. At the time of mail creation in this embodiment, the control unit 17 performs predetermined processing related to mail creation, and the display unit 19 displays a mail creation screen. In addition, when there is a character input, the control unit 17 controls the backlight 32 to turn on the screen backlight 32 of the display unit 19.

  First, a mail creation screen display example, which is a related technique different from the present invention, will be described with reference to FIG.

  In this example, as shown in FIG. 3, it is assumed that the standby screen displayed on the liquid crystal panel 31 has, for example, four background colors as background images, and the background colors are C1 to C4.

  Of these multiple background colors, for example, the default color is often determined by the color of the housing. It is also possible to change the background color according to the user's preference.

  Such a default background color or a background color changed according to the user's preference is a screen for performing various settings, a screen during a game, a screen during mail creation, etc. The same background color is used not only for the standby screen but also for other screens.

  On the mail creation screen displayed at the time of mail creation, the same background color (any one of C1 to C4) as the standby screen is displayed, and a mail editing screen 21 is provided at the center of the screen.

  In the case of such a mail creation screen, most of the screen area of the display unit 19 is occupied by the mail editing screen 21 which is an area for inputting characters, and the background color is displayed only at the top and bottom.

  Next, power consumption of the battery 40 in the example of FIG. 3 will be described. In the following description, consumption of the battery 40 (or simply battery) refers to power consumption unless otherwise specified. The power consumption refers to the amount per unit time.

  When inputting characters with a mobile terminal device such as a mobile phone, the backlight 32 of the screen is turned on for the user's visibility. It is known that the brightness of the backlight 32 can be selected in advance by the user, and the consumption of the battery 40 increases as the brightness of the backlight 32 increases. Therefore, the user who wants to suppress the consumption of the battery 40 needs to darken the brightness of the backlight 32. However, by setting the brightness of the backlight 32 to be dark, there is a problem in that the visibility is lacking, such as when inputting characters in mail creation when the surroundings are bright. At the time of creating a mail, the proportion of time during which the user is inputting characters is larger than the state of the standby screen in FIG. 3, and therefore the time during which the screen backlight 32 is lit is also increased. For this reason, the power consumption on the mail creation screen is greater than that on the standby screen.

  As described above, in a portable terminal device equipped with a technique for automatically adjusting the brightness of the screen backlight according to the display image, the difference in the brightness of the backlight 32 to be lit also depends on the state of the background color. It is understood that the current value consumed varies depending on

  The background colors C1 to C4 are different in power consumption when the backlight 32 is turned on. Here, it is assumed that the background C2 has the highest power consumption when the backlight 32 is lit, and the background color C4 has the lowest power consumption when the backlight 32 is lit.

  As described above, since the lighting time of the backlight 32 is dominant as compared with other screen states at the time of mail creation, the power consumption due to the difference in the background color becomes a large difference. The user often uses the default background color as it is. In addition, when changing the background color, there are few users who change the battery 40 in consideration of the consumption of the battery 40.

  Therefore, in the present invention, when creating a mail with a large difference in power consumption, the background color is uniformly set to the background color with the least power consumption, so that the battery 40 can be made to last longer even when mail is frequently created. Is possible.

  FIG. 4 shows a mail creation screen display in the first embodiment.

  FIG. 4 shows a standby screen and a mail creation screen as in FIG. 3, and it is assumed that the background color of the screen is provided with, for example, four patterns C1 to C4 as in FIG. Similarly to FIG. 3, the background color C2 consumes the most power when the backlight 32 is lit, and the background color C4 consumes the least power when the backlight 32 is lit.

  As shown in FIG. 4, in this embodiment, in order to further suppress the consumption of the battery 40 at the time of mail creation, the background color C4 with the lowest power consumption is uniformly set at the time of mail creation. In this way, by setting the background color uniformly to a color with less power consumption on the mail creation screen, the mobile terminal device set to the background colors C1 to C3 has a mail composition compared to the case of FIG. It becomes possible to reduce the consumption of the battery 40 at the time.

  Next, a background color setting method at the time of mail creation in the present embodiment will be described with reference to FIG.

  First, a user calls a predetermined screen in order to use each function (step S10). Next, the control unit 17 determines whether the called process is a mail creation process (step S20). In the present embodiment, since the background color is changed only at the time of mail creation when the difference in current is the largest depending on the background color, if it is not mail creation processing (step S20: No), a preset screen is displayed as it is. (Step S40).

  When the called process is the mail creation process (step S20: Yes), the control unit 17 changes the current background color to the background color with the least power consumption when the backlight 32 is lit (step S30). At this time, the control unit 17 functions as background color setting means. Note that when the current background color has the least power consumption, the background color is not changed. Subsequently, the display unit 19 displays a screen including a background color and information (guidance etc.) for the user to create a mail based on a command from the control unit 17 (step S40). At this time, the control unit 17 functions as an e-mail processing unit that controls the overall processing related to e-mail.

  The display unit 19 also functions as a backlight adjustment unit that adjusts the luminance of the backlight 32 corresponding to the displayed image. That is, the display unit 19 reduces the current flowing through the backlight 32 and decreases the luminance of the backlight 32 in accordance with the image including the background color changed in step S30.

  Thereafter, when the mail creation is completed and another screen is displayed, the control unit 17 returns to the setting of the background color set before the mail creation (step S50).

  As described above, in this embodiment, the background color is changed only at the time of creating the mail, and the display is performed on the other various screens with the default background color or the background color changed by the user.

  In the present invention, it is possible to extend the battery 40 time by suppressing the consumption of the battery 40 at the time of creating a mail whose usage frequency is increasing recently. In addition, by changing the background color only when creating an email that has the largest difference in power consumption compared to other screens, the background color can be changed for users who have chosen the background color as desired. Thus, the battery 40 can be made to last for a long time.

(Second Embodiment)
In the first embodiment described above, the background color of the mail creation screen is uniformly changed. However, depending on the user, it may be considered that the background color of the screen is more important than the battery consumption at the time of mail creation. Therefore, in the second embodiment, the user can select whether to change the background color of the mail creation screen.

FIG. 6 is a flowchart showing the operation in the second embodiment. First, when a user calls a function (step S10), the control unit 17 determines whether or not the called process is a mail creation process (step S20). If it is determined that mail creation has been called (step S20: Yes), the background color is uniformly changed in the first embodiment, but in the present embodiment, the currently set background color is the backlight 32. It is determined whether or not the background color has low power consumption during lighting (step S21). If the called process is not a mail creation process (step S20: No), the display unit 19 displays a preset screen as it is (step S40).

If the currently set background color is not the background color with the least power consumption when the backlight 32 is lit (step S21: Yes) , the display unit 19 is based on the command of the control unit 17, as shown in FIG. A pop-up screen 25 that prompts the user to change the background color of the mail creation screen is displayed (step S22). At this time, the control unit 17 and the display unit 19 function as selection screen display means. In addition, the pop-up screen 25 can be displayed by changing the background color by displaying, for example, “If the background color of the mail creation screen is changed, battery consumption during mail creation can be reduced.” A message that the consumption of the battery 40 is different is transmitted to the user. When the currently set background color is the background color with the least power consumption when the backlight 32 is lit (step S21: No), the display unit 19 displays the mail creation screen 21 (step S40).

Subsequent to step S22, branch processing for changing the background color is performed (step S23). When it is determined that the user does not change the background color at the time of mail creation and the user selects “Do not change background color” in response to the pop-up display message (step S23: No), the display unit 19 continues. The mail creation screen 21 is displayed (step S40). When the user selects “change background color” (step S23: Yes), the control unit 17 changes the background color to the background color with the least power consumption when the backlight 32 is lit (step S30). The display unit 19 displays the mail creation screen with the changed background color (step S40). After that, when the processing on the mail creation screen is completed, the background color is restored to the same as in the first embodiment (step S50).

  As described above, by allowing the user to select whether or not to change the background color of the mail creation screen, it is possible to correspond to a user who places importance on long-lasting battery 40 and a user who places importance on the background color, respectively. It becomes possible.

(Third embodiment)
As described above, the consumption of the battery 40 due to the difference in the background color at the time of mail creation has an effect when the backlight 32 of the screen is turned on. It is also known that the brighter the screen backlight 32, the greater the difference in power consumption. Therefore, when the brightness of the backlight 32 is set to be dark, there is almost no difference in power consumption when the backlight 32 is turned on due to a difference in background color.

  Therefore, in the third embodiment, only when the brightness of the backlight 32 is set to be bright, the background color of the mail creation screen is changed to reduce the number of scenes whose background color is changed.

  FIG. 8 is a flowchart showing the operation in the third embodiment. In the present embodiment, it is assumed that the user can select the brightness of the backlight 32 of the screen, and here, six levels from level 1 to level 6 can be set. More specifically, it is assumed that the brightness of the backlight 32 is the darkest at the level 1, the brightness of the backlight 32 is the brightest at the level 6, and becomes brighter in order from the level 1 to the level 6. Further, regarding the consumption of the battery 40 when the backlight 32 is lit at each level, in the case of the level 1 to the level 3, the difference in power consumption due to the background color is not large.

  First, the user calls a function (step S10), and when it is determined that mail creation is called (step S20: Yes), the control unit 17 checks the setting state of the brightness of the backlight 32. When the brightness setting of the backlight 32 is brighter than the predetermined reference value, that is, when it is level 4, level 5, or level 6 (step S24: Yes), the control unit 17 is the same as in the second embodiment. The background color is changed to the one with the least power consumption (step S30), and the display unit 19 displays the mail creation screen based on the background color (step S40).

  When the brightness setting of the backlight 32 is darker than the predetermined reference value, that is, when the level is 1, 2, or 3 (step S24: No), the background color is changed when the mail is created. The display unit 19 continues to display the mail creation screen with the current background color setting (step S40). Note that, regardless of whether the backlight 32 is brighter or darker, the background color is then restored as in the above-described embodiment (step S50).

  As described above, by limiting the change of the background color at the time of creating the mail only to the user who sets the brightness of the backlight 32 to be brighter, the condition for changing the background color is reduced, and the user's condition is changed. Power consumption can be reduced efficiently while lowering the influence on the feeling of use.

(Fourth embodiment)
In the first embodiment, the change of the background color is limited only to the time of creating the mail. However, the power consumption difference is also caused by the difference in the background color even in a scene that involves character input (for example, creation of a text memo) other than at the time of creating the mail. It is thought that there is. For example, a user who frequently inputs a memo by using a text memo function provided in a mobile terminal device instead of a memo pad generates a difference in power consumption due to a difference in background color when the text memo is created.

  Therefore, in the fourth embodiment, it is assumed that the user can select a scene whose background color is to be changed.

  FIG. 9 shows a flowchart when the background color is selected in the fourth embodiment. The user performs a predetermined operation, and the background color setting process is started by calling a background color selection function on the screen. The user selects a favorite background color on a predetermined selection screen (step S110). Thereafter, in the present embodiment, a screen for the user to select a scene to be changed to the selected background color is displayed, and the user arbitrarily selects a scene on this screen (step S120). In this step, as in the example of the selection screen shown in FIG. 10, a scene of a screen on which character input or key operations are frequently performed such as mail creation, text input, calculator function, schedule creation, etc. is displayed. Then, the user can select whether or not to change the background color for each. Subsequently, the control unit 17 changes the background color of the screen selected in step S120 to that selected in step S110 (step S130).

  As described above, by allowing the user to select a scene whose background color is to be changed, it is possible to suppress the consumption of the battery 40 even when the mail is not created, and the scene where the user frequently changes the background color. It becomes possible to limit to.

(Fifth embodiment)
Many mobile phones in recent years are equipped with an illuminance sensor that detects ambient brightness. Such a mobile phone adjusts the brightness of the backlight 32 to an optimum brightness according to the ambient brightness input from the illuminance sensor, thereby making it easy to see the screen in a high illuminance environment and a low illuminance environment. It balances the power saving effect below. Hereinafter, a configuration for further reducing power consumption in such a case will be described.

  In FIG. 11, the block diagram of the portable terminal device 2 which concerns on 5th Embodiment is shown. The mobile terminal device 2 includes an illuminance sensor 22 in addition to the configuration of the mobile terminal device 1 shown in the first embodiment.

  The illuminance sensor 22 detects ambient brightness (illuminance). Illuminance information detected by the illuminance sensor 22 is output to the control unit 17. The control unit 17 adjusts the luminance of the backlight 32 of the display unit 19 according to the input illuminance information.

  For example, when it is determined that the surroundings are bright, the control unit 17 adjusts the luminance of the backlight 32 to be bright in consideration of visibility. Conversely, when it is determined that the surrounding is dark, the control unit 17 suppresses power consumption by suppressing the luminance of the backlight 32.

  Therefore, in the present embodiment, the brightness of the screen backlight 32 can be automatically adjusted according to the display image, and the screen at the time of creating the mail according to the ambient brightness detected by the illuminance sensor 22 can be used. By changing the background color, it is assumed that the consumption of the battery 40 is suppressed while considering the visual field of the user.

  FIG. 12 is a flowchart showing the screen calling process of this embodiment. First, when mail creation is started (step S25), the illuminance sensor 22 detects ambient brightness based on an instruction from the control unit 17 (step S26). The control unit 17 determines whether or not the detected ambient brightness is bright (step S27). The reference illuminance for determining whether or not the image is bright is set in advance.

  When it is determined that the surroundings are brighter than the predetermined brightness (step S27: Yes), the control unit 17 sets the background color of the screen to a black screen with low luminance (step S30). With this setting, the user's visibility is improved, and as shown in the first embodiment, the consumption of the battery 40 can be suppressed by using a black background color. Further, when it is determined that the surrounding is darker than the predetermined brightness (step S27: No), the control unit 17 sets the background color of the screen to a white screen with high luminance. As described above, when the surroundings are dark, the battery 40 is consumed less than when the surroundings are bright. Therefore, in consideration of the visibility of the user, the white background color that is easy to see even in a dark situation is set. Note that the brightness level of the background color as an image is relatively determined in the background color group when the brightness of the backlight 32 is the same.

  Thereafter, through the process of step S30 or step S40, the screen display (step S40) and the process of returning the background color (step S50) are performed in the same manner as in the above-described embodiment.

  In this way, in addition to adjusting the brightness of the backlight 32 by changing the background color at the time of mail creation, the user can also improve the visibility of the user by changing the background color of the screen according to the ambient brightness. It becomes possible to suppress the consumption of the battery 40 in consideration.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation and application are possible.

  For example, in each of the above-described embodiments, the power consumption reduction on the e-mail creation screen has been described. However, the present invention is not limited to this. For example, the present invention can be applied to various screens displayed on the display unit 19 such as a call, voice playback, function setting, and the like. Even in this case, it is preferable to apply the present invention to a screen frequently used by the user.

  In each of the above-described embodiments, the background color has been described as a target for reducing power consumption. In addition to this, a background image including a pattern, a figure, a character, a photograph, and the like may be used. In this case, since the brightness varies depending on the area of the image, for example, for a part of the background image displayed on the mail creation screen, the level of power consumption may be determined in advance from a group of a plurality of types of background images. Note that the background color in each of the above-described embodiments shows a uniform color for the entire background image as shown in the example of FIG. 4, so there is no need to consider the display area on the mail creation screen, and the power consumption can be simplified. Reduction processing can be performed.

  The programs executed by the portable terminal devices 1 and 2 in each of the above-described embodiments are a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), and an MO (Magneto-Optical Disk). A system that executes the above-described processing may be configured by storing and distributing the program in a computer-readable recording medium such as the computer and installing the program in a computer that controls the mobile terminal device.

  Further, the program may be stored in a disk device or the like of a predetermined server device on a communication network such as the Internet, and may be downloaded, for example, superimposed on a carrier wave.

  In addition, when the above functions are realized by sharing an OS (Operating System), or when the functions are realized by cooperation between the OS and an application, only the part other than the OS may be stored in a medium and distributed. You may also download it.

  In addition, the above-described hardware configuration and flowchart are examples, and can be arbitrarily changed and modified.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
Display means comprising a liquid crystal panel for displaying an image and a backlight for irradiating the liquid crystal panel with light from the back;
A battery for supplying power to the display means;
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
Backlight adjustment means for adjusting the brightness of the backlight corresponding to the background image displayed on the liquid crystal panel;
Background image setting means for selecting a background image to be displayed from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized when the liquid crystal panel displays the predetermined image; Comprising
A portable terminal device.

(Appendix 2)
A selection screen display means for displaying, on the liquid crystal panel, a guidance screen that allows the user to select whether or not to change the background image when displaying the predetermined image;
The mobile terminal device according to Supplementary Note 1, wherein

(Appendix 3)
The background image setting means changes the background image when the luminance of the backlight is equal to or higher than a predetermined reference value.
The mobile terminal device according to appendix 1 or 2, characterized in that.

(Appendix 4)
The background image setting means sets the background image so that the power consumption is minimized when the liquid crystal panel displays a screen requesting input from a user other than when the predetermined image is displayed.
The portable terminal device according to any one of appendices 1 to 3, wherein

(Appendix 5)
An illuminance sensor that detects ambient illuminance is further provided,
The background image setting means selects the background image having a high luminance when the surrounding is bright, and selects the background image having a low luminance when the surrounding is dark, according to the detected illuminance.
The mobile terminal device according to any one of supplementary notes 1 to 4, wherein:

(Appendix 6)
The background image is a background color image of a predetermined color that is uniform throughout the image.
The mobile terminal device according to any one of supplementary notes 1 to 5, wherein

(Appendix 7)
A method for reducing power consumption of a portable terminal device, comprising: a display unit that includes a liquid crystal panel that displays an image; a backlight that irradiates light to the liquid crystal panel from the back; and a battery that supplies power to the display unit. ,
Prepared in advance so that the power consumption of the backlight is minimized when displaying a predetermined image including a part of a background image and information for a predetermined operation by the user on the liquid crystal panel. Selecting a background image to be displayed from a group of a plurality of types of background images;
A method for reducing power consumption of a portable terminal device.

(Appendix 8)
A computer for controlling a mobile terminal device, comprising: a display means comprising a liquid crystal panel for displaying an image; and a backlight for irradiating the liquid crystal panel with light from the back; and a battery for supplying power to the display means.
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
Background color setting means for selecting a background image to be displayed from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized when the liquid crystal panel displays the predetermined image;
A program characterized by functioning as

DESCRIPTION OF SYMBOLS 1, 2 Portable terminal device 11 Antenna 12 Radio | wireless part 13 Memory 14 Audio | voice / audio signal processing part 15 Output device 16 Microphone 17 Control part 18 Operation part 19 Display part 20 CPU
21 Mail Editing Screen 22 Illuminance Sensor 31 Liquid Crystal Panel 32 Backlight 40 Battery 51 Display Unit 52 E-mail Processing Unit 53 Backlight Adjusting Unit 54 Background Image Setting Unit

Claims (7)

Display means comprising a liquid crystal panel for displaying an image and a backlight for irradiating the liquid crystal panel with light from the back;
A battery for supplying power to the display means;
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
Backlight adjustment means for adjusting the brightness of the backlight corresponding to the background image displayed on the liquid crystal panel;
When the liquid crystal panel displays the predetermined image, a background image to be displayed is selected from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized . A background image setting means for changing the background image when the luminance is equal to or higher than a predetermined reference value ;
A portable terminal device. A selection screen display means for displaying, on the liquid crystal panel, a guidance screen that allows the user to select whether or not to change the background image when displaying the predetermined image;
The mobile terminal device according to claim 1. The background image setting means sets the background image so that the power consumption is minimized when the liquid crystal panel displays a screen requesting input from a user other than when the predetermined image is displayed.
Mobile terminal device according to claim 1 or 2, characterized in that. An illuminance sensor that detects ambient illuminance is further provided,
The background image setting means selects the background image having a high luminance when the surrounding is bright, and selects the background image having a low luminance when the surrounding is dark, according to the detected illuminance.
Portable terminal device according to any one of claims 1 to 3, characterized in that. The background image is a background color image of a predetermined color that is uniform throughout the image.
Portable terminal device according to any one of claims 1 to 4, characterized in that. A method for reducing power consumption of a portable terminal device, comprising: a display unit that includes a liquid crystal panel that displays an image; a backlight that irradiates light to the liquid crystal panel from the back; and a battery that supplies power to the display unit. ,
Prepared in advance so that the power consumption of the backlight is minimized when displaying a predetermined image including a part of a background image and information for a predetermined operation by the user on the liquid crystal panel. Selecting a background image to be displayed from a group of a plurality of types of background images, and changing the background image when the luminance of the backlight is equal to or higher than a predetermined reference value;
A method for reducing power consumption of a portable terminal device. A computer for controlling a mobile terminal device, comprising: a display means comprising a liquid crystal panel for displaying an image; and a backlight for irradiating the liquid crystal panel with light from the back; and a battery for supplying power to the display means.
E-mail processing means for displaying a predetermined image including a part of a background image and information for a user to perform a predetermined operation on the e-mail on the liquid crystal panel;
When the liquid crystal panel displays the predetermined image, a background image to be displayed is selected from a group of a plurality of types of background images prepared in advance so that the power consumption of the backlight is minimized . Background image setting means for changing the background image when the luminance is equal to or higher than a predetermined reference value ;
A program characterized by functioning as

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