JP2005156746A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more reduce the current consumption of mobile phones or other mobile terminals having a display means. <P>SOLUTION: A mobile terminal having a display means 26 uses a display means having a partial display function of setting only a partial area of a display area to a driving state and setting the other area to a non-driving state, as the display means 26 and is provided with; a selection means 28 for selecting which of the partial area and the entire area of the display area should be used for display; and control means means 21 and 27 which make a refresh rate of the display means 26 lower than that for display on the entire display area while performing pertial display on the display means 26, on the basis of selection of display on the partial display area by the selection means 28. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a portable terminal having display means, and more particularly to a device that reduces current consumption.

  Since a portable terminal such as a cellular phone uses a battery as a power source, it is desired to reduce current consumption in order to extend the continuous usable time. For that purpose, it is particularly important to reduce current consumption in a display that displays characters and images.

  Conventionally, in a portable terminal using a liquid crystal display (LCD), as a method for reducing the current consumption, it has been proposed to provide a partial display (partial display) function to the LCD (for example, Patent Document 1). And 2).

  The partial display function means that only a part of the display area of the liquid crystal panel is driven and the remaining area is not driven, or the backlight is divided into a plurality of areas to be driven. This function turns on only the corresponding backlight.

If it is sufficient to display characters or the like only in a part of the display area, the LCD is switched from the normal display mode (the mode in which the entire display area of the liquid crystal panel is driven) to this partial display mode. Current consumption is reduced.
JP-A-6-95621 (paragraph numbers 0013 to 0032, FIGS. 3 to 6) Japanese Patent Laid-Open No. 11-184434 (paragraph numbers 0026 to 35, FIGS. 1 to 4)

  However, in recent years, LCDs provided in cellular phones and the like are mainly used for the purpose of improving image quality, using TFT (thin film transistor) type liquid crystal panels rather than TFD (thin film diode) type liquid crystal panels.

  While the TFD type liquid crystal panel consumes several hundred μA, the TFT type liquid crystal panel consumes several mA to several tens of mA (more than 10 times that of the TFD type). Even if it is performed, it cannot be said that the current consumption is small for the mobile phone.

  In addition, when a screen that displays a clock or the like in the partial display mode can be selected as the standby screen, a screen that does not drive the LCD at all (normally black on a black screen) is selected as the standby screen. Compared with, continuous standby time is considerably shortened.

  In view of the above, the present invention has been made in order to further reduce current consumption in a mobile phone or other mobile terminal having a display unit such as an LCD.

  In order to solve this problem, the mobile terminal according to the present invention is a mobile terminal having display means, and the display means drives only a part of the display area and does not drive the remaining area. A selection means for selecting whether to display in a part of the display area or to display in all areas, and a part of the display by the selection means Control means for causing the display means to perform partial display based on the selection of display in the area, and for lowering the refresh rate of the display means to be lower than the refresh rate for display in all display areas; It is characterized by having.

  In this portable terminal, when the selection means selects to display in a part of the display area of the display means, the display means performs partial display under the control of the control means, and the refresh rate of the display means is normally set. It is lower than when displaying.

  Therefore, when displaying in a part of the display area, in addition to reducing the current consumption of the display means by the partial display itself, the current consumption of the display means is further reduced by reducing the refresh rate.

  As a result, when displaying in a part of the display area, the current consumption can be further reduced as compared with the conventional case.

  Also, if the refresh rate is lowered when displaying in all display areas, the user will recognize flicker (flickering of the screen), whereas if the refresh rate is lowered when performing partial display, Since only a part of the display area is driven, flicker can be made difficult to recognize.

  In this portable terminal, as an example, the selection unit is preferably an operation unit capable of performing an operation of selecting a screen to be displayed in a part of the area as the standby screen.

  As a result, partial display is performed on the standby screen and the current consumption is reduced by lowering the refresh rate. Therefore, display is performed on a part of the display area on the standby screen (for example, a clock or the like). Display), the continuous standby time can be extended.

  In addition, since the standby screen is not a screen on which the user always watches, it is possible to make it more difficult to recognize flicker.

  According to the present invention, in a mobile phone or other portable terminal having a display means, when displaying in a partial display area of the display means, the partial display is performed and the refresh rate is lowered. Can be further reduced than before, and the effect of making it difficult to recognize flicker can be obtained.

  In addition, by performing partial display on the standby screen and lowering the refresh rate, continuous standby time can be extended even when displaying in a part of the display area on the standby screen (for example, displaying a clock or the like). In addition, it is possible to obtain an effect that the flicker can be made more difficult to recognize.

  Hereinafter, an example in which the present invention is applied to a mobile phone will be specifically described with reference to the drawings. FIG. 1 is a front view showing an appearance of a mobile phone according to the present invention.

  The mobile phone 1 has a structure in which a telephone upper part 1a and a telephone lower part 1b are connected by a hinge. On the top of the telephone 1a, there are an earpiece 2, a liquid crystal panel 3, a disk-type jog dial 4, a mail button 5, a call button 6, a clear button 7, an Internet connection button 8, a power / end button 9, a my select button 10, and a shutter button. 11 etc. are provided.

  The telephone lower portion 1b is provided with other operation button groups (dial buttons and the like) 12, a mouthpiece (not shown in the figure, but located on the lower side of the liquid crystal panel 3) and the like.

  The mobile phone 1 can be folded with the liquid crystal panel 3 facing outward by rotating the phone upper portion 1a and the phone lower portion 1b in parallel with each other as shown in FIG.

  As a standby screen of the cellular phone 1, a menu screen is operated with the jog dial 4 to display the display area of the liquid crystal panel 3 as shown in FIG. It is possible to select a “partial clock display screen” in which the date and time are displayed only in the center area, and the remaining areas are all black.

  FIG. 4 is a block diagram showing an outline of the circuit configuration of the entire mobile phone 1. Communication is performed via a CPU 21 that controls the entire mobile phone 1, a ROM 22 that stores programs executed by the CPU 21, a RAM 23 that stores various data such as image data, and an antenna 24 built in the mobile phone 1. A communication processing unit 25 for performing the operation, an LCD controller 27 for supplying RGB signals and control signals to the LCD module 26, an operation unit 28 (the jog dial 4 and each button in FIG. 1), and a camera unit 29 (built in the cellular phone 1). The CCD camera and its controller) are connected to the control line 32, respectively.

  Further, the CPU 21, ROM 22, RAM 23, communication processing unit 25, LCD controller 27, camera unit 29, speaker 30, and microphone 31 are connected to the data line 33.

  The LCD module 26 includes a driver for driving the liquid crystal panel 3, a backlight, and a VRAM (graphic RAM) in the liquid crystal panel 3 of FIG. The liquid crystal panel 3 is a normally black TFT color liquid crystal panel.

  The LCD module 26 has a function of driving only a part of the display area of the liquid crystal panel 3 and setting the remaining area to the non-driven state, and lighting only the backlight corresponding to the driven area ( Partial display function). Various methods for performing partial display on the LCD are disclosed in the aforementioned Patent Documents 1 and 2 and other various documents, and the LCD module 26 employs any of these methods. There may be.

  The LCD controller 27 sets the refresh rate of the liquid crystal panel 3 to 60 Hz when performing normal display on the liquid crystal panel 3 (displaying in all display areas of the liquid crystal panel 3).

  FIG. 5 is a flowchart showing the process of the part related to the control of the refresh rate of the liquid crystal panel 3 among the processes executed by the CPU 21 of FIG.

  In this process, first, from the state in which normal display is performed on the liquid crystal panel 3, the “partial clock display screen” (FIG. 3) is selected as the standby screen by operating the jog dial 4. Whether or not the display area has been switched to a state where display should be performed (step S1), and from the state where “partial clock display screen” is selected as the standby screen, a screen other than the standby screen is displayed. It is determined whether or not the display has been switched to a state in which normal display should be performed due to the transition (step S2), and the display content of the liquid crystal panel 3 should be changed (for example, the display time should be advanced in the “partial clock display screen”) The determination of whether or not (step S3) is repeated until yes in any step.

  If YES in step S1, the LCD module 26 is switched to the partial display mode via the LCD controller 27 (step S4). Based on this, the LCD module 26 drives only the central area where the date and time are displayed among the display areas of the liquid crystal panel 3 as shown in FIG. Only the backlight corresponding to the display area in the driving state is turned on.

  Subsequent to step S4, by changing the operation clock supplied from the LCD controller 27 to the LCD module 26, the refresh rate of the liquid crystal panel 3 is switched to 30 Hz, which is 1/2 of the normal display (step S5). Subsequently, the image data for the “partial clock display screen” in the RAM 23 is displayed as data to be displayed in the central area of the display area of the liquid crystal panel 3 as shown in FIG. 26 is written (drawn) in the VRAM 26 (step S6). Then, the process returns to step S1.

  If YES in step S2, the LCD module 26 is switched to the normal display mode (a mode in which the entire display area of the liquid crystal panel is driven) via the LCD controller 27 (step S7). Subsequently, by changing the operation clock, the refresh rate of the liquid crystal panel 3 is switched to 60 Hz during normal display (step S8).

  Subsequently, the image data for the current screen in the RAM 23 is drawn on the VRAM in the LCD module 26 via the LCD controller 27 as data to be displayed in all display areas of the liquid crystal panel 3 as usual (step S9). . Then, the process returns to step S1.

  If YES in step S3, it is determined whether or not the “partial clock display screen” is currently displayed (step S10). If yes, the image data for the “partial clock display screen” to be displayed next (display time has advanced) in the RAM 23 is displayed in the central portion of the display area of the liquid crystal panel 3 as in step S6. The data is displayed in the VRAM in the LCD module 26 as data to be displayed in the area (step S11). Then, the process returns to step S1.

  On the other hand, if NO, the image data to be displayed next in the RAM 23 is drawn in the VRAM in the LCD module 26 in the same manner as in step S9 (step S12). Then, the process returns to step S1.

  Next, how the current consumption of the LCD is reduced in the mobile phone 1 will be described. When the user performs an operation of selecting the “partial clock display screen” as the standby screen, partial display is performed on the liquid crystal panel 3 and the refresh rate of the liquid crystal panel 3 is 1/0 of the refresh rate during normal display. 2 (steps S4 and S5 in FIG. 5).

  Therefore, when the “partial clock display screen” is displayed as the standby screen, the current consumption of the liquid crystal panel 3 and the backlight is reduced by the partial display itself, and the refresh rate of the liquid crystal panel 3 is lowered to reduce the liquid crystal. The current consumption of panel 3 is further reduced.

  Specifically, if the current consumption of the liquid crystal panel 3 when the refresh rate is 60 Hz is 4 mA, the current consumption of the liquid crystal panel 3 is reduced to about 2 mA, which is ½, by reducing the refresh rate to 30 Hz. Is done.

  As described above, when the “partial clock display screen” is displayed as the standby screen, the current consumption is greatly reduced.

  As a result, even when “partial clock display screen” is selected as the standby screen, the continuous standby time is extended (when a screen with a black screen that does not drive the liquid crystal panel at all is selected as the standby screen). The difference in continuous standby time can be reduced.

  Further, if the refresh rate is lowered when performing normal display, the amount of charge stored in the storage capacitor of the pixel of the liquid crystal panel 3 fluctuates greatly within one frame period (accumulated due to discharge in the second half of one frame period). The user perceives flicker because the amount of charge is considerably reduced.

  On the other hand, when the refresh rate is lowered when performing partial display, the fluctuation of the accumulated charge amount remains only in a part of the display area, so that it is difficult to recognize flicker.

  Furthermore, since the standby screen is not a screen on which the user always watches, it is possible to make it more difficult to recognize flicker.

  In the above example, the “partial clock display screen” as shown in FIG. 3 can be selected as the standby screen. However, other screens that are displayed in a part of the display area of the liquid crystal panel 3 can be selected as the standby screen, and when the screen is selected, partial display is performed. The refresh rate of the liquid crystal panel 3 may be lowered.

  Alternatively, as a screen other than the standby screen, a screen to be displayed in a part of the display area of the liquid crystal panel 3 can be selected, and when the screen is selected, a partial display is performed and the liquid crystal panel is displayed. 3 may be lowered.

  In the above example, in the liquid crystal panel 3 in which the refresh rate during normal display is 60 Hz, the refresh rate is switched to 30 Hz during partial display. However, the present invention is not limited to this, and in the liquid crystal panel 3 having a refresh rate of 60 Hz during normal display, the refresh rate may be lowered to an appropriate rate of less than 60 Hz during partial display. Furthermore, in the liquid crystal panel 3 in which the refresh rate during normal display is a rate other than 60 Hz, the refresh rate may be lowered to an appropriate rate lower than that during partial display.

  In the above example, the present invention is applied to a mobile phone having an LCD as a display means. However, the present invention is not limited to this, and a mobile phone having a display means (for example, an organic EL) other than an LCD or other than a mobile phone. The present invention may also be applied to a portable terminal having a display means (for example, a PDA).

It is a front view which shows the external appearance of the mobile telephone by this invention. It is a figure which shows a mode that the mobile telephone of FIG. 1 is folded. It is a figure which shows an example of the standby screen of the mobile telephone of FIG. FIG. 2 is a block diagram illustrating a circuit configuration of the mobile phone in FIG. 1. 6 is a flowchart showing processing executed by the CPU of FIG. 4 in association with control of the refresh rate of the liquid crystal panel.

Explanation of symbols

1 Mobile phone 3 Liquid crystal panel 4 Jog dial 21 CPU
23 RAM
26 LCD module 27 LCD controller

Claims (2)

In a portable terminal having a display means,
The display means has a partial display function of driving only a part of the display area and setting the remaining area to a non-driven state.
A selection means for selecting whether to display in a part of the display area or to display in all areas;
Based on the selection of display in a part of the display area by the selection unit, the display unit performs the partial display and also displays the refresh rate of the display unit in the entire display region. A portable terminal comprising control means for lowering the refresh rate at the time. The mobile terminal according to claim 1,
The mobile terminal according to claim 1, wherein the selection means is an operation means capable of performing an operation of selecting a screen to be displayed in a partial area as a standby screen.

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