JPH0667840A - Display device - Google Patents

Abstract

PURPOSE:To provide a display device capable of reducing power consumption. CONSTITUTION:When a selection signal is applied, the selection signal is inputted to a display area specifying means 10 and an irradiation area restricting means 15. The means 10 specifies a display area based upon the inputted selection signal and outputs the specified area to a display part 20. The display part 20 receives the display area specification and executes display only by the display area. The selection signal inputted to the means 15 restricts an irradiation area and outputs the restricted result to a light emitting means 5. The means 5 receives the irriadiation area restriction and irradiates only the irradiation area with irradiation light. Namely the light emitting means 5 irradiates only the area displayed by the display part 20 with irradiation light based upon the selection signal. Since only the area displayed based upon the selection signal is irriadiated, power consumption can be reduced without consuming useless power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to reduction of power consumption.

[0002]

2. Description of the Related Art A display device is used for displaying information in, for example, a computer. In particular, in recent years, various types of display devices have been developed and used according to the application. For example, it is a liquid crystal display or a plasma display of a portable computer (so-called laptop computer).

Information is displayed on the screens of these display devices and is also used when confirming the information input by the operator. At this time, information is displayed using the entire screen of a predetermined size. By using such a display device, information can be recognized quickly and accurately.

[0004]

However, the conventional display device has the following drawbacks. First, even when a part of the screen is used for display, the entire screen is used for display. That is, on the screen of a predetermined size, power is consumed not only in the part displaying the information but also in the part not displaying the information. Therefore, power is consumed even in a place where no display is made, which is a waste.

The above-mentioned useless power consumption is a problem even in a normal computer, but particularly in a computer driven by a battery such as a laptop computer. That is, if the electric power is wasted because it is driven by the battery, the movable time becomes short. If the movable time is to be lengthened, the battery must be increased, and the weight of the computer itself is increased, which increases the size.

Therefore, an object of the present invention is to provide a display device capable of reducing power consumption.

[0007]

According to a first aspect of the present invention, there is provided a display area designating means for designating a display area in the display section in accordance with a given selection signal and displaying only in the display area. It is characterized by having.

A display device according to a second aspect comprises a light emitting means for emitting irradiation light to the display portion to assist display on the display portion, and the display of the light emitting means is displayed in response to the selection signal. It is characterized in that it is provided with an irradiation area limiting means for limiting the irradiation area to the part.

In the display device according to a third aspect of the present invention, the display on the display section is performed by giving a control signal to the X-axis control line and the Y-axis control line, and the display area designating means gives the selection signal. Accordingly, one or both of the X-axis control line and the Y-axis control line is limited to specify the display area by giving a control signal.

A display device according to a fourth aspect has a plurality of display signal storage means for storing the display signal, and the display signal is stored in each display signal storage means so as to correspond to a display place of the display section. The display area designating means designates the display area by selecting the display signal storage means according to the selection signal.

In the display device according to a fifth aspect, a desired setting area is selected from a plurality of setting areas stored in the setting area storage means and a setting area storage means for storing a plurality of preset setting areas. It is characterized in that a setting area input means that is input and input, and a selection signal is output to the display area designating means according to the setting area selected through the setting area input means.

According to another aspect of the present invention, a display device detects a remaining capacity of a power source and outputs a remaining capacity signal to a power supply remaining capacity detecting means, and receives a remaining capacity signal to calculate a display area corresponding to the remaining capacity signal. The calculating means for outputting the selection signal and the display area designating means are characterized in that the size of the display area is continuously limited and the display area is designated according to the selection signal.

According to a seventh aspect of the present invention, there is provided a display device, wherein a set area storing means for storing a plurality of preset setting areas, a power capacity detecting means for detecting a remaining capacity of a power source and issuing a remaining capacity signal, and a remaining capacity signal. And a setting area selecting means for selecting a setting area corresponding to the remaining capacity signal from the setting area storage means and outputting a selection signal indicating the setting area. According to the selection signal, the size of the display area is limited stepwise and the display area is designated.

[0014]

In the display device according to the first aspect of the present invention, the display area designating means designates the display area in the display section according to the given selection signal, and displays only in the display area.

Therefore, it is possible to specify the display area in accordance with the selection signal, and the display is not carried out except the desired display area.

In the display device according to the second aspect, the light emitting means emits irradiation light to the display portion to assist the display on the display portion. The irradiation area limiting unit limits the irradiation area of the display unit of the light emitting unit according to the selection signal.

Therefore, it is possible to limit the irradiation area of the display unit of the light emitting means, and the irradiation light is not emitted to the area other than the irradiation area.

In the display device according to the third aspect, the display on the display section is performed by giving a control signal to the X-axis control line and the Y-axis control line. The display area designating unit designates the display area by limiting the one or both of the X-axis control line and the Y-axis control line and applying a control signal.

Therefore, the display area can be specified by limiting the control signals on the X-axis control line and the Y-axis control line according to the selection signal, and the X-axis control line and the Y-axis control line other than the display area can be specified.
No control signal is applied to the axis control line.

In the display device according to the fourth aspect, the plurality of display signal storage means store the display signals. Then, the display signal is stored in each display signal storage means so as to correspond to the display location of the display unit. The display area designating means designates the display area by selecting the display signal storage means according to the selection signal.

Therefore, it is not necessary to select the display signal storage means which stores the display signal corresponding to the desired display location from the plurality of display signal storage means and the display signal storage means which stores the display signal other than the display location.

In the display device according to the fifth aspect, the setting area storage means stores a plurality of setting areas set in advance. Then, the setting area is selected and input from the plurality of setting areas stored in the setting area storage means to the setting area input means. A selection signal is output to the display area designating means in accordance with the setting area selected through the setting area input means.

Therefore, the display of the selected setting area is performed, and the display of the area other than the setting area is not performed.

In the display device according to the sixth aspect, the power remaining capacity detecting means detects the remaining capacity of the power source and outputs the remaining capacity signal. The calculation means receives the remaining capacity signal, calculates a display area corresponding to the remaining capacity signal, and outputs a calculation area signal. Then, the display area designating unit continuously limits the size of the display area in accordance with the calculation area signal and designates the display area.

Therefore, the size of the display area is continuously limited according to the remaining capacity of the power supply, and the display is performed according to the remaining capacity, and the display is not performed in areas other than the limited display area.

In the display device according to the seventh aspect, the setting area storage means stores a plurality of setting areas set in advance. The power supply capacity detecting means detects the remaining capacity of the power supply and issues a remaining capacity signal. And the display area designating means is
The remaining capacity signal is fetched from the power capacity detecting means, a setting area corresponding to the remaining capacity signal is selected from a plurality of setting areas stored in the setting area storage means, and a display area is designated.

Therefore, the size of the display area is stepwise limited from the set area stored according to the remaining capacity of the power source, and display is performed according to the remaining capacity, and display is performed in areas other than the limited display area. Absent.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An outline of the structure of a display device according to an embodiment of the present invention will be described with reference to FIG. A display unit 20 is provided in the display device 2, and a display area designating unit 10 is connected to the display unit 20. In addition, the display unit 20
Further, a light emitting means 5 for emitting light after irradiation and an irradiation area limiting means are provided.

The operation of the display device 2 will be described with reference to FIG. First, a selection signal is applied to the display device 2 from the outside. This selection signal is input to the display area designating means 10 and the irradiation area limiting means 5. Here, the display area designating means 1
0 designates a display area (display area) based on the input selection signal, and outputs it to the display unit 20. The display section 20 receives the designation of the display area and displays only in the display area. On the other hand, the selection signal input to the irradiation area limiting means 15 limits the area to be irradiated with the irradiation light (irradiation area),
It outputs to the light emitting means 5. The light emitting means 5 receives the limitation of the irradiation area and irradiates only the irradiation area with the irradiation light.
That is, the light emitting unit 5 irradiates the irradiation light only to the region where the display unit 20 displays based on the selection signal.

An embodiment of the present invention will be described below with reference to the drawings. First, an example in which a plasma display is applied as a display device will be given. FIG. 2 is a block diagram showing the configuration of this embodiment. The host computer 10 uses the signal line 50
It is connected to the plasma display 20 via.
The plasma display 20 is provided with display drivers X1, X2, X3, X4, X5 in the X-axis direction and display drivers Y1, Y2, Y3, Y4 in the Y-axis direction. The host computer 10 is also connected to a driver controller 30, and the driver controller 30 is connected to the plasma display 20 via a control line 60. Control line 60
Is connected to all display drivers in the X-axis direction and the Y-axis direction of the plasma display 20.

Generally, in a plasma display, a display driver is connected through wires to all bus lines arranged in the X-axis and Y-axis in the display. Then, the display driver outputs and controls a display signal for each wire. Then, the display signal from the wire is input to the bus lines of the X-axis and the Y-axis, and the intersection point of the X-axis and the Y-axis is caused to emit light for display.

The case of displaying only a part of the screen will be described below. Here, as shown in FIG. 3, description will be given assuming that display is performed only in the area D1. First, the operator inputs a command to set the display area to D1 using a keyboard (not shown). This command is, for example, X
This is done by inputting the coordinates and the Y coordinate.

The host computer 10 sends the display data through the signal line 50 via the video RAM (V-RAM) provided therein (see FIG. 2). On the other hand, the host computer 10 outputs a control signal to the driver controller 30 based on the command of the display area input above. The driver controller 30 receives this and
Display driver X1, X2, X corresponding to the command
Only Y3, Y1 and Y2 are operated, and other display drivers X4, X5, Y3 and Y4 are not operated. Therefore, only the area D1 is displayed on the plasma display 20.

Of course, it is not possible to see the display in the area other than the area D1, but it is effective from the viewpoint of power saving when the important display is concentrated in the area D1.

In the above embodiment, when the display area is made small, the data that should be displayed is not displayed. However, if the display data is reduced and sent from the host computer 10 according to the size of the display area, all the data can be displayed (reduced display). This also applies to each of the following embodiments.

Next, an example in which the above display device is operated by another program will be described. In the above embodiment, the driver controller 30 controls the display driver based on the display position of the character input by the keyboard. That is, the drive of the display driver is controlled according to the display location of the character, and the area for displaying the character is set. On the other hand, in the present embodiment, a plurality of display area sizes are stored in advance, a desired screen size is selected from among them, and characters are displayed within the screen size.

FIG. 2 and FIG. 4 which is an operation flowchart.
Details of this operation will be described with reference to FIG. Figure 2 here
It is assumed that the display selection of the screen size (large or small) is performed through the host computer 10. First, a switch (not shown) of the host computer 10 is turned on (FIG. 2, FIG. 4, step S2). Then, the host computer 10 is activated and a setting menu (not shown) is displayed on the screen of the plasma display 20 (FIG. 4, step S4). In this case, two setting menus are displayed, one for displaying the large screen size and the other for displaying the small screen size. Then, the operator selects a desired menu from the displayed setting menus (FIG. 4, step S6). For example, to display a small screen size, a menu code with a small screen size is input to the host computer 10 through the keyboard. Then, the screen size is set to a small size based on the screen size previously stored in the memory (not shown) of the host computer 10 (FIG. 4, step S10).

The specific operation of this setting is as follows. First, the operator inputs a menu code having a small screen size into the host computer 10 through the keyboard.
Next, the host computer 10 extracts a signal for setting the screen size of the small screen from the memory according to the menu code of the small screen size. For example, it is assumed here that the small screen size is the screen size G2 in FIG. 7A. The host computer 10 outputs a signal for setting the screen size G2 to the driver controller 30. The driver controller 30 takes in this signal, and the screen size G2
Determine which display driver to drive to display. Here, display driver X
2, X3, X4 and Y2, Y3 are driven to display screen size G
Judge that 2 is displayed. Therefore, the display controller 30 uses a display driver X other than the above.
A control signal for stopping the driving of 1, X5 and Y1, Y4 is output to the control line 60. Thus, the small screen size, which is the screen size G2, is set.

Next, the operator inputs the characters to be displayed into the host computer 10 through the keyboard. The host computer 10 stores this character in the V-RAM as a display signal. The display signal stored in the memory of the host computer 10 is input to all display drivers through the signal line 50. Then, the display driver drives each in accordance with the display signal and tries to display characters. However, as described above, the driving of the display drivers X1, X5 and Y1, Y4 is stopped. Therefore, no character is displayed in the area displayed by these display drivers. Then, the screen size set in this way is small (screen size G
The display is performed only in 2) and the processing of the desired application is performed (FIG. 4, step S15).

To display a large screen size,
Similar to the above, the screen size is set to a large size at the time of step S6. That is, the operator inputs a menu code having a small screen size into the host computer 10 through the keyboard. Then, the screen size is set to a large size (FIG. 4, step S8). Here, it is assumed that the large screen size is the screen size G1 in FIG. 7A. Next, the host computer 10 outputs a signal for setting the screen size G1 to the driver controller 30. The driver controller 30 takes in this signal and determines which display driver to drive in order to display the screen size G1. And
The driver controller 30 determines to display all the screen sizes G1 by driving all the display drivers. Therefore, the driver controller 30 outputs a control signal to the control line 60 to drive all display drivers. This control signal is input to all display drivers. Thus, the screen size G1
A large screen size is set.

Next, as in the above example, the operator inputs characters or the like to be displayed in a large screen size into the host computer 10 through the keyboard. The host computer 10 stores this character in the memory as a display signal. And
The display signal stored in the memory is input to all display drivers through the signal line 50. The display driver is driven based on the display signal to display characters. In this case, neither display driver takes in a control signal for stopping driving. Therefore, all display drivers are driven to display characters. That is, a large screen size (screen size G
All displays are made in 1). Then, the processing of the desired application is performed with the screen size kept large (FIG. 4, step S15).

In this way, an arbitrary screen size is selected from a plurality of screen sizes stored in advance, and the subsequent processing is performed with the selected size as it is. Therefore, in the present embodiment, it is possible to perform processing by selecting a small screen size, as compared with the conventional one in which the screen size is constant and cannot be selected, so that it is possible to reduce power consumption. Become. In the present embodiment, the screen size is set to two, large and small, but the screen size is increased to increase the size in multiple steps, such as large medium, large small, medium large, and medium. You may set it.

Further, an example in which the above display device is operated by another program will be described. In the above embodiment, the desired screen size is extracted from the screen size stored in advance, and the display is performed only within the extracted screen size. Also in this embodiment, a plurality of display area sizes are stored in advance. However, the remaining capacity of the power supply is automatically detected at regular intervals, and the size of the stored display area is automatically selected and displayed according to the remaining capacity at the time of detection. Flow charts of the operation of this embodiment are shown in FIGS.

For example, it is assumed that the present embodiment is applied to the host computer 10 which is a laptop computer. The same operation as above is performed from step S2 to step S6. That is, the switch is turned on and a desired menu is selected from the displayed setting menus. In this embodiment, interrupt processing 1 is set (FIG. 4, step S).
12).

When the interrupt processing 1 is set, first, the remaining capacity of the power supply is detected in the host computer 10 (FIG. 5, step S32). Specifically, the CPU of the host computer 10 detects the voltage of a battery (not shown) that is a power source. The remaining capacity of the battery can be recognized by detecting the voltage. Then, the battery detection operation is performed at an arbitrary time interval (for example, every 10 minutes). Next, it is determined whether or not the remaining capacity of the power supply is equal to or more than the threshold value (FIG. 5, step S34). For example, it is assumed that the threshold is set to 50%, the screen size is set to large when the remaining capacity of the power source is 50% or more, and the screen size is set to small when the remaining capacity is less than 50%.

If the CPU detects that the remaining capacity of the battery at the present time is 60%. Since this remaining capacity of 60% is determined to be equal to or greater than the threshold value (50%), the screen size is set large (FIG. 5, step S36). The screen size G1 shown in FIG. 7A shows the large screen size. The operation of setting the screen size G1 is as in the above embodiment.
The display controller 30 determines which display driver to drive to display the screen size G1. Then, it outputs a control signal for controlling the driving of a specific display driver. In this way, the screen size is set large by controlling the drive of the display driver.

Next, the process returns to the application process of step S15 while the screen size of the screen size is kept large (FIG. 5, step S40). That is, the application is processed using the display within the large screen size. For example, it is assumed that another 10 minutes have elapsed while processing the application. Then, a program for automatically performing the interrupt processing 1 is selected (FIG. 5, step S).
30). Here, the CPU again detects the remaining capacity of the battery. If the detection result of this time is detected as 49%,
The screen size is determined to be less than the threshold value (50%), and the screen size is set to small (FIG. 5, step S38). The screen size G2 shown in FIG. 7A indicates that the screen size is small.
The operation of setting 2 is similar to the case of the screen size G1. Then, the process returns to step S15 again with the screen size smaller than the screen size being maintained (FIG. 5, step S4).
0). Perform application processing in a small screen size. That is, the application is processed using the display within the small screen size.

In this way, the remaining capacity of the power source is automatically detected at regular time intervals, and the screen size corresponding to the remaining capacity is automatically extracted and set from the screen sizes stored each time. Then, by repeating such an operation, the application is processed with a screen size corresponding to the remaining capacity of the power supply with the passage of time. Therefore, the present embodiment automatically detects the remaining capacity of the power supply with the passage of time as compared with the conventional one in which the screen size is constant over time,
In addition, as shown in FIG. 7A, the screen size G according to the remaining capacity
Since processing can be performed by selecting 1 or G2 (large or small screen size), it is possible to reduce power consumption. In the present embodiment, the screen size to be stored is set to be large and small, but the screen size is increased to
For example, it may be set in multiple stages, such as large medium, large small, medium large, and medium. Further, in the present embodiment, the time interval for detecting the remaining capacity of the power source is set to 10 minutes, but it may be shorter than 5 minutes or longer than 20 minutes.

Further, an example in which the above display device is operated by another program will be described. In the present embodiment, the remaining capacity of the power source is automatically detected at regular time intervals as in the above embodiments. However, the size of the display area is automatically calculated, set, and displayed according to the remaining capacity of the power supply at the time of detection.
This operation will be described in detail with reference to FIG. 2 and the operation flowcharts of FIGS. Also in this case, it is assumed that the present embodiment is applied to the host computer 10 which is a laptop computer. The same operation as above is performed from step S2 to step S6. In other words, switch on
Then, select a desired menu from the displayed setting menus. Then, the interrupt process 2 for performing the operation in this embodiment is set (FIG. 4, step S14).

When the interrupt processing 2 is set, first, the remaining capacity of the power source is detected in the host computer 10 (FIG. 6, step S18). Specifically, the CPU of the host computer 10 detects the voltage of a battery (not shown) that is a power source. Then, the battery detection operation is performed at an arbitrary time interval (for example, every 10 minutes). Now, assume that the remaining capacity of the battery is 95%. Here, the size of the screen is next calculated (FIG. 6, step S20). For example, the length of the screen size is L, the remaining capacity of the battery is α, and the constant for calculating the screen size is K. Then, the size of the screen is tentatively expressed by the equation of the lateral length of the screen L = K × α. Incidentally, it is assumed that the vertical length of the screen is determined in proportion to the horizontal length, for example, one third of the horizontal length L of the screen.

The actual values are substituted into the above equation for calculation, and the screen size is set based on the calculated result (FIG. 6, step S22). The plasma display 20 is shown in FIG. 7B.
And the change in screen size obtained and displayed by the above equation. It is assumed that the screen size G10 is calculated based on the current remaining capacity of the power supply of 95%. Then screen size G
10 is set and displayed on the plasma display 20. The operation of setting the screen size G10 will be described below. The remaining capacity of 95% detected by the CPU of the host computer 10 is temporarily stored in the memory. Next, the CPU substitutes the remaining capacity of 95% stored in the memory into the equation of L = K × α to obtain the horizontal length of the screen. Next, the vertical length of the screen is obtained based on the obtained horizontal length of the screen. The screen size G10 thus obtained is stored in the memory. The operation of setting the screen size G10 based on the vertical and horizontal lengths of the screen stored in the memory will be described below.

The vertical and horizontal lengths of the screen stored in the memory are output to the display controller 30. The display controller 30 determines which display driver should be driven to display the screen size G10. Here, the display controller 30
Determines to drive all the display drivers to display the screen size G10. Therefore, the display controller 30 outputs a control signal to the control line 60 to drive all display drivers.
Thus, the screen size G10 corresponding to the current remaining capacity of the power supply of 95% is set. Then, the state of the screen size G10 is held and the processing of the desired application is performed (FIG. 4, step S15).

It is assumed that 10 minutes have elapsed while processing the application in step S15.
Then, as in the case described above, the CPU again detects the remaining capacity of the battery (FIG. 6, step S18). For example, if the remaining capacity this time is detected as 90%, which is smaller than the last time,
The size of the screen is calculated by substituting a value into the above equation L = K × α according to this detection signal (FIG. 6, step S20). That is, the calculated horizontal size of the screen is calculated, and the vertical size of the screen is calculated based on the calculated horizontal size. The screen size thus obtained is stored in the memory. Here, it is assumed that the screen size stored in the memory is G20.

Next, the calculated screen size G20 is set (FIG. 6, step S22). The screen size G20 is set in the same manner as the screen size G10 is set.
The vertical and horizontal lengths of the screen stored in the memory are output to the display controller 30. The display controller 30 determines which display driver should be driven to display the screen size G20. Here, the display controller 30 includes the wires X1S of the display driver X1, the wires X5S of X5, the wires Y1S of Y1, and the wire Y4 of Y4 shown in FIG.
It is determined that the display drivers other than S are driven to display the screen size G20. That is, the wire X1S
Excluding display drivers X1, X2, X3, X
4, display driver X5 excluding wire X5S and display driver Y1, Y excluding wire Y1S
2, display driver Y4 except Y3 and wire Y4S is driven. Therefore, the display controller 30 outputs a control signal for driving the above-mentioned display driver and wire to the control line 60. In this way, the screen size G corresponding to the current remaining capacity of the power supply of 90%
20 is set. Comparing the screen size G20 and the previously set screen size G10, the screen size G20 is smaller. In this way, the screen size gradually decreases in proportion to the remaining capacity of the power supply which changes with the passage of time. Then, while the screen size of the screen size G20 is maintained, the process returns to step S15 and the processing of the application is performed.

In this way, the remaining capacity of the power source is automatically detected at regular time intervals, and the screen size (screen size G10, G20 ... Shown in FIG. 7B) corresponding to the remaining capacity is automatically calculated each time. Set. Then, by repeating such an operation, the application is processed with a screen size corresponding to the remaining capacity of the power supply with the passage of time. Therefore, in the present embodiment, as compared with the conventional one in which the screen size is constant over time, the remaining capacity of the power supply is automatically detected over time, and the screen size is automatically calculated and set. Since it is possible to perform the processing, it is possible to reduce power consumption. In this embodiment, the horizontal length of the screen size is first calculated, and then the vertical length is calculated in proportion to the horizontal length. It may be calculated and the lateral length may be calculated in proportion thereto, or both lengths may be calculated simultaneously. Further, in the present embodiment, the time interval for detecting the remaining capacity of the power supply is set to 1
Although it is set to 0 minutes, it may be shortened to 5 minutes or longer than 20 minutes. Further, another embodiment using the above display device will be described. In this embodiment, a case where a transmissive liquid crystal display is applied instead of the plasma display will be described. In the above display device, the power consumption is reduced by controlling the driving of the display driver and the size of the screen to be displayed. However, in this embodiment, the power is reduced by controlling the lighting location of the backlight that is always lit when displaying.

In general, since a transmissive liquid crystal display does not have a light emitting property, a backlight such as an EL (electroluminescence) is turned on to illuminate the display from the back side of the display in order to see the display. The characters displayed on the transmissive liquid crystal display can be seen only by the irradiation light. That is, in the transmissive liquid crystal display, even if the display is performed, the display cannot be seen unless the backlight or the like is turned on and light is emitted. Usually, the backlight is interlocked with a switch of a computer or the like, and when the computer is turned on, the backlight is also turned on.

FIG. 8 is a block diagram showing the structure of the display device in this embodiment. The liquid crystal display 20 is connected to the host computer 10 via a signal line 50. Further, a backlight controller 45 is connected to the host computer 10. The backlight controller 45 is connected to the backlight unit 35 via a backlight control line 70, and the backlight unit 35 is provided behind the liquid crystal display 20. FIG. 9 is a diagram showing an example of the arrangement of the backlight units 35. Here, a total of four EL (electroluminescence) backlights BL1, 2, 3, 4 are arranged in four rows vertically in the backlight unit 35,
The liquid crystal display 20 is irradiated with irradiation light.

The outline of the operation of such a display device will be described below. The operator inputs characters to be displayed on the host computer 10. The entered characters are stored in the memory (not shown) of the host computer 10. Then, the host computer 10 takes out the stored character from the memory and outputs it to the signal line 50. The output signal is input to the liquid crystal display 20 as a display signal, and the liquid crystal display 20 is input based on the input display signal.
Displays a character on the screen. For example, it is assumed that characters are displayed on the entire surface of the liquid crystal display 20 as shown in FIG. 10A. At this time, all the four backlights of the backlight unit 35 are in the ON state, and the liquid crystal display 20 is irradiated with light. Therefore, the operator can see the characters shown in FIG. 10A.

For example, assume that the operator wants to see only the lower part DR5 of the characters shown in FIG. 10A. Then, the operator uses the keyboard (not shown) to move the lower part DR5.
A code for selecting and displaying only the characters is input to the host computer 10. This code is temporarily stored in the memory of the host computer 10 and output to the backlight controller 45. Backlight controller 45
Determines which backlight the input code will turn on and which backlight will turn off. Then, a signal for turning off the specific backlight is output to the backlight control line 70. The backlight provided in the backlight unit 35 is turned off based on this signal. In this case, the operator operates the lower part DR5 of the liquid crystal display 20.
Since only one wants to see, the backlights other than the lower part DR5 are turned off. That is, the backlights BL1 and BL2 of the backlight unit 35 shown in FIG. 9A are turned off, and the backlights BL3 and BL4 are continuously lit. A diagram showing this state is shown in FIG. 10B. That is, in FIG. 10B,
Although the liquid crystal display 20 itself is displaying as shown in FIG. 10A, no light is emitted because the backlight is not lit. Therefore, the liquid crystal display 2
Only the lower part DR5 of 0 is visible (FIG. 10).
B).

In this way, only the backlight of the selected lower portion DR5 is turned on and the other backlights are turned off to assist the display. Therefore, in the present embodiment, it is possible to reduce the power consumption without the conventional backlight of an unnecessary portion irrelevant to the display consuming the power.

Although the transmissive liquid crystal display is used in this embodiment, another display such as a transflective liquid crystal display may be used as long as the backlight assists the display. Also EL for the backlight
Although (electroluminescence) is used, another light emitting member, for example, CCFL (cold cathode tube) may be used. Further, as shown in FIG. 9A, the backlight is divided into four and arranged in four vertically, but another arrangement method, for example, the backlight is divided into ten and arranged in five rows horizontally and two rows vertically. Good.
Alternatively, a backlight having another shape, for example, a backlight having a rectangular shape as shown in FIG. 9B, and a small rectangle and a large rectangle may be combined to be used as the large backlight BL50 and the small backlight BL60.

Further, another embodiment using the above display device will be described. In this embodiment, an EL (electroluminescence) display is applied instead of the transmissive liquid crystal display. In the above display device, the power consumption is reduced by controlling the drive of the display driver, controlling the size of the screen to be displayed, and controlling the backlight. However, in this embodiment, the power is reduced by controlling the memory that stores the characters to be displayed.

Generally, an EL display operates in the same manner as the above plasma display. That is,
It is connected to bus lines arranged on the X and Y axes in the display. Then, the display driver outputs a display signal to the bus line to cause the light emitting body at the intersection of the X axis and the Y axis to emit light for display.

FIG. 11 is a block diagram showing the structure of the display device according to this embodiment. A power controller 80 is connected to the host computer 10, and the power controller 80 includes a video signal line 95 and a VRAM control line 9
It is connected to the video RAM 100 via 0. Further, the power controller 80 has a controller control line 96.
Is also connected to the display controller 60 through. There are four video RAMs 100 (V1, V2, V3
V4), and the display controller 6
It is connected to 0. Then, the display controller 60 uses the signal from the video RAM 100 for the EL
It controls the display 20. The four video RAMs (V1, V2, V3, V4) correspond to the display locations of the EL display 20, and FIG. 12 shows an example of the display locations on the screen stored in each video RAM. That is, the display location DR1 on the screen corresponds to the video RAMV1, the display location DR2 corresponds to the video RAMV2, the display location DR3 corresponds to the video RAMV3, and the display location DR4 corresponds to the video RAMV4.

The outline of the operation of such a display device will be described below. First, the operator inputs a character to be displayed on the host computer 10 by using a keyboard (not shown). For example, assume that the operator inputs the characters shown in FIG. 10A. The input characters are stored in the memory (not shown) of the host computer 10. Then, the host computer 10 takes out the stored character from the memory and outputs it to the power controller 80. The power controller 80 has an address decoder and a register built therein, and distributes a signal from the memory of the host computer 10 to a predetermined VRAM in the video RAM 100. That is, the power controller 80 determines which display location on the screen the character is displayed on, and which VRAM corresponds to the display location. In this case, since the characters as shown in FIG. 10A are displayed, it is necessary to perform the display at all the display locations DR1, DR2, DR3, DR4 shown in FIG. Therefore, the power controller 80 is not limited to all the video RAMs corresponding to the above display locations.
It is determined to use (V1, V2, V3, V4).

Then, the power controller 80 outputs a character signal from the memory of the host computer 10 to the video RAM (V1, V2, V3, V4) through the video signal line 95. From the power controller 80, all the video R is simultaneously transmitted via the VRAM control line 90.
A control signal for operating the AM is output. Further, the power controller 80 outputs to the display controller 60 through the controller control line 96 a control signal that causes the EL display 20 to display all the video signals extracted from the video RAM.

Video RAM (V1, V2, V3, V4)
The character signal input to is temporarily stored and taken out by the display controller 60. The extracted character signals are collected by the display controller 60 and then output to the EL display 20. And EL
The display 20 performs display based on the character signal from the display controller 60. Thus, the characters of FIG. 10A are displayed.

Now, for example, assume that the operator wants to display only the lower part DR5 of the characters shown in FIG. 10A. Then, the operator inputs into the host computer 10 a code for selecting and displaying only the characters of the lower portion DR5 using a keyboard (not shown). This code is temporarily stored in the memory of the host computer 10 and output to the power controller 80. Here, the power controller 80 determines which video RAM the code input by the display location DR5 operates. Display location DR
As shown in FIG. 12, 5 is composed of display locations DR3 and DR4. Therefore, the power controller 80 specifies the video RAM corresponding to the display locations DR3 and DR4. That is, the video RAMs V3 and V4 are displayed at the display location DR5.
Judge as the video RAM to be displayed. Then, the video RAM specified by the VRAM control line 90, that is, the video RA
A control signal for activating only MV3 and V4 and stopping the other video RAMs is output (see FIG. 11).

This control signal is used for all video RAMs (V
1, V2, V3, V4) to stop the operation of the video RAMs V1 and V2. This control signal is simultaneously sent to the display controller 6 through the controller control line 96.
You have entered 0. That is, this control signal is sent to the display controller 60 as video RAM V3 and VRAM
This is a control signal for extracting a character signal from only 4 and displaying all the extracted video signals on the EL display 20. Thus, the characters displayed on the EL display 20 are as shown in FIG. 10B.

Therefore, in this embodiment, an unnecessary video RAM is arbitrarily selected at the time of display, and other video RAMs are selected.
Do not activate. Therefore, it is possible to reduce power consumption as compared with the case where all the video RAMs are driven as in the related art. Although the video RAM 100 is divided into four in the present embodiment, the video RAM 100 may be divided into a larger number, for example, six, for finer control or less. Further, in this embodiment, the video RA
Although M100 is divided horizontally, another division method, for example, vertical division may be used. Further, although the EL display is used for the display unit in the present embodiment, other display elements, such as a liquid crystal display and a plasma display, which temporarily store the display signal and then display may be used.

In the above embodiments, the embodiments for selecting the display area and the embodiments for selecting the backlight area may be arbitrarily combined.

As described above, power consumption can be reduced by various methods. This can extend battery life, especially in those driven by batteries, such as laptop computers.
Therefore, it is possible to drive a laptop computer driven by a battery having a small capacity for a long time.

[0073]

In the display device according to the first aspect of the present invention, the display area designating means designates the display area in the display unit according to the given selection signal and displays only in the display area.

That is, it becomes possible to specify the display area in accordance with the selection signal, and display is not performed in areas other than the desired display area.

Therefore, it is possible to reduce the power consumption by not displaying anything other than the display area.

In the display device according to the second aspect, the light emitting means emits irradiation light to the display portion to assist the display on the display portion. The irradiation area limiting unit limits the irradiation area of the display unit of the light emitting unit according to the selection signal. That is, it becomes possible to limit the irradiation area of the display unit of the light emitting means, and the irradiation light is not emitted outside the irradiation area.

Therefore, it is possible to reduce the power consumption by not emitting the irradiation light to the area other than the irradiation area.

In the display device according to the third aspect, the display on the display section is performed by giving a control signal to the X-axis control line and the Y-axis control line. The display area designating unit designates the display area by limiting the one or both of the X-axis control line and the Y-axis control line and applying a control signal. That is, it becomes possible to limit the control signals on the X-axis control line and the Y-axis control line to specify the display area, and not to apply the control signal to the X-axis control line and the Y-axis control line other than the display area.

Therefore, it is possible to reduce the power consumption by not applying a control signal to the X-axis control line and the Y-axis control line other than the display area.

In the display device according to the fourth aspect, the plurality of display signal storage means store the display signals. Then, the display signal is stored in each display signal storage means so as to correspond to the display location of the display unit. The display area designating means designates the display area by selecting the display signal storage means according to the selection signal. That is, there is no need to select a desired display signal storage means from a plurality of display signal storage means and select a display signal storage means that stores other than the display location.

Therefore, it is possible to reduce the power consumption by not selecting the display signal storage means storing the area other than the display area.

In the display device according to the fifth aspect, the set area storage means stores a plurality of preset set areas. Then, the setting area is selected and input from the plurality of setting areas stored in the setting area storage means to the setting area input means. A selection signal is output to the display area designating means in accordance with the setting area selected through the setting area input means. That is, only the display area corresponding to the selected setting area is displayed.

Therefore, it is possible to reduce the power consumption by not displaying anything other than the display area.

In the display device according to the sixth aspect, the power remaining capacity detecting means detects the remaining capacity of the power source and outputs the remaining capacity signal. The calculation means receives the remaining capacity signal, calculates a display area corresponding to the remaining capacity signal, and outputs a calculation area signal. Then, the display area designating unit continuously limits the size of the display area in accordance with the calculation area signal and designates the display area. That is, the size of the display area can be continuously limited according to the remaining capacity of the power supply.

In the display device according to the seventh aspect, the setting area storage means stores a plurality of setting areas set in advance. The power supply capacity detecting means detects the remaining capacity of the power supply and issues a remaining capacity signal. And the display area designating means is
The remaining capacity signal is fetched from the power capacity detecting means, a setting area corresponding to the remaining capacity signal is selected from a plurality of setting areas stored in the setting area storage means, and a display area is designated. That is, the size of the display area can be limited stepwise according to the remaining capacity of the power supply.

Therefore, in claims 6 and 7, it is possible to reduce power consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a display device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration when a plasma display is applied to the display device of the present invention.

FIG. 3 is a diagram showing an example of a display on the display shown in FIG.

FIG. 4 is a flowchart showing an operation of the display device shown in FIG.

5 is a flowchart showing an operation of the display device shown in FIG.

FIG. 6 is a flowchart showing an operation of the display device shown in FIG.

FIG. 7 is a diagram showing an example of a display on the display shown in FIG.

FIG. 8 is a block diagram showing the configuration of another embodiment of the present invention.

9 is a diagram showing an arrangement of backlights in the backlight unit shown in FIG.

10 is a diagram showing an example of a display on the display shown in FIG.

FIG. 11 is a block diagram showing the configuration of another embodiment of the present invention.

12 is a diagram showing the correspondence between the video RAM shown in FIG. 11 and the display locations on the display.

[Explanation of symbols]

 2 ... Display device

Claims (7)

[Claims] 1. A display device having a display section for displaying based on a display signal, wherein a display area in the display section is designated in accordance with a given selection signal, and a display area is displayed only in the display area. A display device comprising: a designating means. 2. The display device according to claim 1, wherein a light emitting unit that emits irradiation light to the display unit to assist display on the display unit, the light emitting unit with respect to the display unit according to the selection signal. A display device comprising: an irradiation area limiting means for limiting an irradiation area. 3. The display device according to claim 1, wherein the display on the display unit is performed by giving a control signal to the X-axis control line and the Y-axis control line, and the display area designating unit selects. A display device, wherein a display area is designated by limiting a part of one or both of an X-axis control line and a Y-axis control line according to a signal and giving a control signal. 4. The display device according to claim 1, further comprising a plurality of display signal storage means for storing the display signal, wherein each display signal storage means stores a display signal corresponding to a display location of a display section. The display device is characterized in that the display region designating unit designates a display region by selecting a display signal storage unit according to the selection signal. 5. The display device according to claim 1, wherein a desired setting area is selected from setting area storage means for storing a plurality of preset setting areas and a plurality of setting areas stored in the setting area storage means. 2. A display device, comprising: a setting area input means that is selected and input; and a selection signal is output to the display area designating means in accordance with the setting area selected through the setting area input means. 6. The display device according to claim 1, wherein the power remaining capacity detecting means for detecting the remaining capacity of the power source and outputting the remaining capacity signal, and receiving the remaining capacity signal to calculate a display area corresponding to the remaining capacity signal. A display unit that outputs a selection signal according to the selection signal; and a display unit that specifies the display region by continuously limiting the size of the display region according to the selection signal. 7. The display device according to claim 1, wherein a setting area storage means for storing a plurality of preset setting areas, a power capacity detecting means for detecting the remaining capacity of the power source and issuing a remaining capacity signal, and a remaining capacity signal. In response to the setting area storage means, a setting area selecting means for selecting a setting area corresponding to the remaining capacity signal from the setting area storage means and outputting a selection signal indicating the setting area is provided. A display device, wherein the size of a display area is limited stepwise in accordance with the selection signal to specify the display area.