JP2004085682A - Display device and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device and a display method for reducing a harmful effect on convenience of a user and reducing power consumption as much as possible. <P>SOLUTION: A display part 106 displays a text, a picture, or the both. An illuminating part 104 emits light to illuminate the display part 106. An illumination control part 103 stops the light emitted from the illuminating part 104, when a state of the device not to be inputted to an electronic instrument from the user is continued for a predetermined time. A display control part 105 lowers the gradation number of the display part 106 by control from the illumination control part 103 corresponding to the light emitted from the illuminating part 104 being stopped. When the electronic instrument is inputted from the user, in a state of the device where the light of the illuminating part 104 is stopped and the gradation of the display part 106 is lowered, the illumination control part 103 turns the illuminating part 104 on. Moreover, the display control part 105 returns the gradation of the display part 106 to an ordinary state. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device of an electronic device driven by a battery, and more particularly to a reduction in power consumption of this type of display device.
[0002]
[Prior art]
Portable electronic devices having a display device such as a mobile phone, a PDA, and a notebook personal computer are often driven by a battery. It is preferable that such an electronic device can be used for a long time by being driven by a battery.
[0003]
On the other hand, with the advancement of functions of mobile phones and the like, the content displayed on the display device is shifting from conventional text-based content to photo- and video-based content. For this reason, in recent years, display devices of mobile terminals have been multicolored. In order to display more colors while maintaining the same rewriting time as before, the display device needs to operate with a faster clock. In order to operate at high speed, the power consumption of the display device in recent years has been increasing.
[0004]
In order to extend the usable time by battery operation, the electronic device shifts to a mode for reducing power consumption (hereinafter referred to as a power save mode) when there is no input such as a key operation for a certain period of time. .
[0005]
In the power save mode, the conventional electronic device turns off the screen of the display device, for example. However, it is not preferable to completely turn off the screen of the display device depending on the type and use of the electronic device. Therefore, other conventional electronic devices reduce the brightness of the backlight in the power save mode. Still another conventional electronic device includes a reflective liquid crystal display device, and turns off a backlight in a power save mode to continue display by sunlight or illumination.
[0006]
[Problems to be solved by the invention]
As described above, the power consumption of an electronic device having a display device which can be driven by a battery is reduced as compared with the related art. However, in this type of electronic device such as a mobile phone, the lower the power consumption, the better. In addition, low power consumption and long usable time by battery drive are factors that greatly affect the commercial value of this type of electronic device. As electronic devices become more sophisticated, there is a strong demand for means for further reducing power consumption of display devices. However, in order to reduce power consumption, if the user's usability deteriorates, such as when the image brightness is low or the image quality is poor when the user wants to view the screen, it is overturned.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a display device and a method in which power consumption is reduced as much as possible with little influence on the usability of a user.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a display device of the present invention is a display device provided in an electronic device,
A display for displaying text, images, or both,
An illumination unit that emits light applied to the display unit;
An illumination control unit that controls an amount of light emitted from the illumination unit under predetermined conditions;
A display control unit that changes the number of gradations of the display unit according to the amount of light emitted from the illumination unit under the control of the illumination control unit.
[0009]
Therefore, according to the present invention, the number of gradations of the display unit is changed according to the amount of light emitted from the illumination unit.
[0010]
Note that, when a state in which no input is made by the user to the electronic device continues for a predetermined time, the illumination control unit may stop the light of the illumination unit, and the display control unit may reduce the number of gradations of the display unit.
[0011]
Therefore, as the state where there is no user input continues for a predetermined time and the light of the illumination unit is stopped, the number of gradations of the display unit is reduced.
[0012]
Further, the electronic device has a mechanism for making the display unit invisible to a user,
When the display unit is visible to the user and a state in which no input is made from the user to the electronic device continues for a predetermined time, the illumination control unit stops the light of the illumination unit, and the display control unit stops the light of the display unit. The gradation may be lowered.
[0013]
Further, when the display unit becomes invisible to the user, the illumination control unit may stop the light of the illumination unit, and the display control unit may return the gray scale of the display unit to normal.
[0014]
Further, in a state where the light of the illumination unit is stopped and the gradation of the display unit is reduced, when there is an input from the user to the electronic device, the illumination control unit turns on the illumination unit, and the display The control unit may return the gradation of the display unit to normal.
[0015]
According to one embodiment of the present invention, the illumination unit irradiates the display unit with a backlight.
[0016]
According to another aspect of the present invention, the illumination unit illuminates the display unit with a front light.
[0017]
The display method of the present invention has a display unit for displaying text, an image or both of them, and a lighting unit for emitting light emitted to the display unit, and is a display method for a display device included in an electronic device,
Reducing the amount of light emitted from the illumination unit under predetermined conditions,
Changing the number of gradations of the display unit according to the amount of light emitted from the illumination unit.
[0018]
In addition, on condition that a state where there is no input from the user to the electronic device has continued for a predetermined time, the light of the illumination unit is stopped,
The gradation number of the display unit may be reduced in response to the stoppage of the light of the illumination unit.
[0019]
Further, the electronic device has a mechanism for making the display unit invisible to a user,
In a state in which the display unit is visible to the user, and on condition that a state in which no input from the user to the electronic device has continued for a predetermined time, stopping the light of the illumination unit,
The gradation number of the display unit may be reduced in response to the stoppage of the light of the illumination unit.
[0020]
Further, the method may further include a step of stopping the light of the illumination unit when the display unit becomes invisible to the user, and returning the gradation of the display unit to normal.
[0021]
Further, in a state where the light of the illumination unit is stopped and the gradation of the display unit is reduced, when there is an input from the user to the electronic device, the illumination unit is turned on, and the gradation of the display unit is changed. The method may further include a step of returning to normal.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings.
[0023]
The display device of the present invention is mounted on a battery-driven electronic device such as a mobile phone, a portable information terminal, and a notebook personal computer. In the present embodiment, a configuration based on a mobile phone is exemplified. The display device of the present embodiment turns off the backlight and shifts to the power save mode when the user does not input any key operation or the like to the electronic device for a predetermined time, and also sets the number of gradations of the screen (display Color number).
[0024]
FIG. 1 is a block diagram illustrating a configuration of a display device according to an embodiment of the present invention. Referring to FIG. 1, a display device 100 according to the present embodiment includes a main control unit 101, a main storage unit 102, a backlight control unit 103, a backlight 104, a display control unit 105, a display unit 106, a display storage unit 107, and a timer 108. have.
[0025]
The main control unit 101 is a control unit that controls the operation of the entire display device 100. The main control unit 101 controls the backlight control unit 103, the display unit control unit 105, the timer 108, and the like to perform a cooperative operation.
[0026]
The main storage unit 102 is a storage device that is read and written by the main control unit 101. The main storage unit 102 stores programs and data necessary for the main control unit 101 to execute various processes.
[0027]
The backlight control unit 103 turns on and turns off the backlight 104 according to an instruction from the main control unit 101.
[0028]
The backlight 104 illuminates the display unit 106 with light from the back, and brightens the screen of the display unit 106.
[0029]
The display control unit 105 controls the display unit 106 to display a desired image. The image displayed on the display unit 106 by the display control unit 105 is, for example, an image received from the main control unit 101.
[0030]
Further, the display control unit 105 can cause the display storage unit 107 to store the display data to be displayed on the display unit 106 and display the display data stored in the display storage unit 107 on the display unit 106.
[0031]
In addition, the display control unit 105 can change the number of display colors (the number of gradations) of the display unit 106 according to an instruction from the main control unit 101. In this embodiment, there are a display color number normal mode and a display color number reduction mode depending on the number of display colors. The display color number is the maximum number of the display unit 106 in the display color number normal mode, and is smaller than the maximum number in the display color number reduction mode. The number of display colors in the display color number reduction mode can be, for example, 最大 or の of the maximum number.
[0032]
The display unit 106 displays characters, images, and the like on a screen.
[0033]
The display storage unit 107 is a storage device that is read and written by the display control unit 105.
[0034]
The timer 108 is a timer whose start / stop is controlled by the main control unit 101. When a predetermined time set by the main control unit 101 has elapsed, the timer 108 notifies the main control unit 101 that the timer has expired.
[0035]
FIG. 2 is a flowchart illustrating the operation of the display device of the present embodiment. Referring to FIG. 2, first, display control unit 105 turns on the display of display unit 106 in accordance with an instruction from main control unit 101 (step 201). Next, the backlight control unit 103 turns on the backlight 104 in accordance with an instruction from the main control unit 101 (step 202).
[0036]
Next, the main control unit 101 initializes the timer 108 (Step 203). Next, the main controller 101 determines whether or not a key operation has been performed (step 204). When a key operation is performed, the backlight control unit 103 turns on the backlight 104 according to an instruction from the main control unit 101 (step 205). If the backlight 104 has already been turned on, it is continuously turned on.
[0037]
Next, the main control unit 101 determines whether the current display color number mode is the display color number reduction mode (step 206). If the current display color number mode is the display color number decrease mode, the main control unit 101 switches the display color number mode to the display color number normal mode (step 207), and thereafter returns to the processing of step 203. In addition, in the determination of step 206, if the current display color number mode is not the display color number decrease mode, that is, if the display color number normal mode, the main control unit 101 returns to the processing of step 203 without doing anything. .
[0038]
If no key operation has been performed in step 204, the main control unit 101 determines whether the timer 108 has expired (step 208). If the timer 108 has not expired, the main control unit 101 returns to the process of step 204. If the timer 108 has expired, the backlight control unit 103 turns off the backlight 104 according to an instruction from the main control unit 101 (step 209). Next, the main control unit 101 switches the display color number mode to the display color number reduction mode (step 210), and returns to the processing of step 204.
[0039]
FIG. 3 is an example of a timing chart showing signals when the main control unit 101 notifies the display control unit 105 of display data. Referring to FIG. 3, a synchronization signal (sync) 301, a clock signal (clock) 302, and a data signal (data) 303 are used to notify display data. Although the synchronization signal actually includes a vertical synchronization signal and a horizontal synchronization signal, the synchronization signal 301 shows one of them as an example. The interval between the pulses of the synchronization signal 301 is the scanning cycle (t [sec]). The clock signal 302 counts n clocks during one scanning cycle. The display data 303 is synchronized with the clock signal 302. That is, n pieces of display data are notified during the scanning cycle t [sec]. Generally, data is transferred by a parallel signal, but an example in which the data is transferred by a serial signal is shown here for the sake of simplicity.
[0040]
The display color number reduction mode described above has the same scanning cycle as the display color number normal mode, and the number of display colors is reduced. Therefore, the display color number reduction mode has a lower clock frequency than the display color number normal mode. In general, the lower the frequency of a signal, the lower the power consumption. Therefore, the power consumption of the display device 100 in the display color number reduction mode is lower than that in the display color number normal mode.
[0041]
In the display color number reduction mode, the image quality is inferior because the color expression capability of each pixel is lower than in the display color number normal mode. However, when the backlight is off, the deterioration of the image quality is not so obvious as to be visible, and the reduction in the number of display colors does not cause a problem for the visibility of the user. Since the display device 100 of the present embodiment turns off the backlight and shifts to the display color number reduction mode, in addition to the reduction of the power consumption by turning off the backlight, the effect of the reduction of the power consumption by the reduction of the number of display colors is achieved. , And there is no influence of image quality deterioration due to the decrease in the number of display colors.
[0042]
The relationship between the number of display colors and the clock frequency in the display device 100 of the present embodiment will be described.
[0043]
For example, it is assumed that the number of tones (the number of display colors) of the display device 100 in the display color number normal mode is 32 and the clock frequency is 1. If the number of gradations is changed to 16 without changing the scanning time, the clock frequency becomes 4/5 and the power consumption is reduced. Similarly, when the number of gradations is set to eight, the clock frequency becomes ／.
[0044]
As described above, according to the present embodiment, if no key operation is performed for a certain period of time, the display device turns off the backlight, reduces the number of display colors, and switches to the display color number reduction mode to display data. , The power consumption can be greatly reduced by turning off the backlight and reducing the number of display colors. Further, the number of display colors can be reduced without affecting the image quality.
[0045]
Next, another embodiment of the present invention will be described. A display device according to another embodiment of the present invention is mounted on an electronic device having a folding mechanism such as a mobile phone or a PHS terminal. In the present embodiment, the display unit of the display device is invisible when the foldable function part is closed. At that time, the display device of the present embodiment turns off the backlight and turns off the display. The display device according to the present embodiment shifts to the display color number reduction mode when the foldable mechanism is open and no input has been performed for a certain period of time.
[0046]
FIG. 4 is a block diagram illustrating a configuration of a display device according to another embodiment of the present invention. Referring to FIG. 4, the display device 400 includes a main control unit 401, a main storage unit 102, a backlight control unit 103, a backlight 104, a display control unit 105, a display unit 106, a display storage unit 107, a timer 108, and an open / close state. A detection unit 402 is provided.
[0047]
The main storage unit 102, the backlight control unit 103, the backlight 104, the display control unit 105, the display unit 106, the display storage unit 107, and the timer 108 are the same as those in FIG.
[0048]
The main control unit 402 is a control unit that controls the entire display device 400 similarly to the main control unit 101 of FIG. 1, but differs from that of FIG. 1 in that it is connected to the open / closed state detection unit 402.
[0049]
The open / closed state detection unit 402 identifies the open / closed state of the folding mechanism of the electronic device. The open / closed state detection unit 402 notifies the main control unit 401 of the “open” or “closed” state.
[0050]
FIG. 5 is a flowchart showing the operation of the display device of FIG. Referring to FIG. 5, first, display control unit 105 turns on the display of display unit 106 in accordance with an instruction from main control unit 401 (step 501). Next, the backlight control unit 103 turns on the backlight 104 in accordance with an instruction from the main control unit 401 (step 502).
[0051]
Next, the main control unit 401 initializes the timer 108 (Step 503). Next, the main control unit 401 acquires information from the open / closed state detection unit 402 and determines whether the state is “open” (step 504). If not, the backlight control unit 103 turns off the backlight 104 according to the instruction from the main control unit 401 (step 505). Next, the display control unit 105 turns off the display of the display unit 106 according to the instruction from the main control unit 401 (step 506). Next, the main control unit 401 switches the display color number mode to the display color number normal mode (step 507), and thereafter returns to the processing of step 503. Here, in the display color number normal mode, the backlight is turned on when the state is changed from the “closed” state to the “open” state, so that the display is started in the display color number normal mode at that time. To do that.
[0052]
If it is determined in step 504 that the electronic device is in the “open” state, the main control unit 401 determines whether the folding mechanism of the electronic device has changed from the “closed” state to the “open” state (step 508). A change in the open / close state can be detected by storing the past open / close state and comparing the new state with the past state.
[0053]
If the state has changed from the "closed" state to the "opened" state, the display control unit 105 turns on the display unit 106 in accordance with an instruction from the main control unit 401 (step 509). Next, the backlight control unit 103 turns on the backlight 104 according to an instruction from the main control unit 401 (step 510).
[0054]
If it is determined in step 508 that the state has not changed from the “closed” state to the “opened” state, or after the processing in step 510, the main control unit 401 determines whether or not a key operation has been performed (step 511). When a key operation is performed, the backlight control unit 103 turns on the backlight 104 in accordance with an instruction from the main control unit 401 (step 512). If the backlight 104 has already been turned on, it is continuously turned on.
[0055]
Next, the main control unit 401 determines whether or not the current display color number mode is the display color number reduction mode (step 513). If the current display color number mode is the display color number decrease mode, the main control unit 401 switches the display color number mode to the display color number normal mode (step 514), and thereafter returns to the processing of step 503. Further, in the determination at step 513, if the current display color number mode is not the display color number reduction mode, that is, if the display color number normal mode, the main control unit 401 returns to the processing of step 503 without doing anything. .
[0056]
If no key operation has been performed in step 511, the main control unit 401 determines whether the timer 108 has expired (step 515). If the timer 108 has not expired, the main control unit 401 returns to the process of step 504. If the timer 108 has expired, the backlight control unit 103 turns off the backlight 104 in accordance with an instruction from the main control unit 401 (step 516). Next, the main control unit 401 switches the display color number mode to the display color number reduction mode (step 517), and returns to the processing of step 504.
[0057]
As described above, according to the present embodiment, if no key operation is performed for a certain period of time in the foldable electronic device in the “open” state, the display device turns off the backlight and reduces the number of display colors. Since the clock frequency of the display data is reduced by switching to the display color number reduction mode by reducing the display color number, the power consumption can be greatly reduced by turning off the backlight and reducing the number of display colors. Further, the number of display colors can be reduced without affecting the image quality.
[0058]
Another embodiment of the present invention will be described. In the display device according to still another embodiment of the present invention, the number of display colors can be changed in three or more steps.
[0059]
For example, the display device may use 16 gray scales in a normal state, switch to 32 gray scales when high image quality is required, and switch to 8 gray scales when there is no input for a certain period of time. Further, the display device may use 32 gray scales in a normal state, and switch to 16 gray scales when no input continues for a certain period of time or more, and switch to 8 gray scales when no input continues.
[0060]
The timer value of the timer 108 set to determine whether the display device of each embodiment described above switches the display color number mode may be a fixed value or may be set by the user. .
[0061]
Further, the number of display colors (the number of gradations) selected by the display device of each embodiment in each state may be a fixed value or may be set by the user.
[0062]
Further, it is assumed that the display device of each embodiment is mainly mounted on a portable communication device such as a mobile phone. However, the display device of each embodiment can be mounted on various other electronic devices. The display device of the present invention can be applied to any device that can be driven by a battery, such as a PHS terminal, a PDA, and a notebook personal computer, and preferably operates for a long time by battery drive.
[0063]
Further, in each embodiment, an example has been described on the assumption that the display unit 106 is a transmissive or slightly transmissive LCD and the backlight 104 is used. However, the display unit 16 is a reflective or slightly reflective LCD. Is also good. In that case, the display device is provided with a front light instead of the backlight 104 as an illumination unit. The present invention can be applied as it is even if the backlight 104 is replaced with a front light.
[0064]
Further, in the configurations of the display devices 100 and 400 of each embodiment (FIGS. 1 and 4), the display storage unit 107 does not necessarily have to exist. In this case, since the display data always flows in real time between the main control units 101 and 401 and the display control unit 105, the effect of reducing the power consumption according to the present invention is greater.
[0065]
Further, the present invention is not limited to the examples of each embodiment, and it is needless to say that each embodiment can be appropriately changed within the scope of the technical idea of the present invention.
[0066]
【The invention's effect】
According to the present invention, since the number of gradations of the display unit is changed according to the amount of light emitted from the illumination unit, by selecting an appropriate number of gradations according to the brightness of the display unit, Power consumption can be reduced without affecting visibility.
[0067]
Further, since the number of gradations of the display unit is reduced in response to the state where no user input continues for a predetermined time and the light of the illumination unit is stopped, the light of the illumination unit of the display device is used when the user is not using the electronic device. And a reduction in the number of gray scales of the display unit provides a large power consumption reduction effect.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a display device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an operation of the display device of the embodiment.
FIG. 3 is an example of a timing chart showing signals when the main control unit notifies the display control unit of display data.
FIG. 4 is a block diagram illustrating a configuration of a display device according to another embodiment of the present invention.
FIG. 5 is a flowchart illustrating an operation of the display device of FIG. 4;
[Explanation of symbols]
100, 400 Display device 101, 401 Main control unit 102 Main storage unit 103 Backlight control unit 104 Backlight 105 Display control unit 106 Display unit 107 Display storage unit 108 Timer 201 to 210, 501 to 517 Step 301 Synchronization signal 302 Clock signal 303 Data signal 402 Open / closed state detector

Claims (12)

A display device provided in an electronic device,
A display for displaying text, images, or both,
An illumination unit that emits light applied to the display unit;
An illumination control unit that controls an amount of light emitted from the illumination unit under predetermined conditions;
A display device comprising: a display control unit configured to change a gradation number of the display unit according to an amount of light emitted from the illumination unit under the control of the illumination control unit. 2. The display according to claim 1, wherein when a state in which no input is made from the user to the electronic device continues for a predetermined time, the illumination control unit stops the light of the illumination unit, and the display control unit lowers the gradation of the display unit. apparatus. The electronic device has a mechanism to make the display unit invisible to a user,
When the display unit is visible to the user and a state in which no input is made from the user to the electronic device continues for a predetermined time, the illumination control unit stops the light of the illumination unit, and the display control unit stops the light of the display unit. The display device according to claim 1, wherein the gradation is reduced. The display device according to claim 3, wherein when the display unit is invisible to a user, the illumination control unit stops the light of the illumination unit, and the display control unit returns the gray scale of the display unit to normal. In the state where the light of the illumination unit is stopped, and there is an input from the user to the electronic device in a state where the gradation of the display unit is reduced, the illumination control unit turns on the illumination unit, and the display control unit The display device according to any one of claims 2 to 4, wherein the display device returns the gradation of the display unit to normal. The display device according to claim 1, wherein the illumination unit irradiates a backlight to the display unit. The display device according to claim 1, wherein the illumination unit irradiates the display unit with a front light. A display method for displaying a text, an image, or both of them, including a display unit for displaying light and an illuminating unit for emitting light emitted to the display unit, a display method provided in an electronic device,
Reducing the amount of light emitted from the illumination unit under predetermined conditions,
Changing the number of gradations of the display unit according to the amount of light emitted from the illumination unit. On the condition that a state where no input has been made from the user to the electronic device has continued for a predetermined time, the light of the lighting unit is stopped,
9. The display method according to claim 8, wherein the number of gradations of the display unit is reduced in response to the stoppage of the light of the illumination unit. The electronic device has a mechanism to make the display unit invisible to a user,
In a state in which the display unit is visible to the user, and on condition that a state in which no input from the user to the electronic device has continued for a predetermined time, stopping the light of the illumination unit,
The display method according to claim 8, wherein the number of gradations of the display unit is reduced in response to the stoppage of the light of the illumination unit. The display method according to claim 10, further comprising a step of stopping the light of the illumination unit when the display unit becomes invisible to a user, and returning the display unit to normal gradation. In the state where the light of the illumination unit is stopped, and there is an input from the user to the electronic device in a state where the gradation of the display unit is lowered, the illumination unit is turned on, and the gradation of the display unit is normally set. The display method according to claim 9, further comprising a returning step.

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