JP3282740B2 - Power-saving flat panel display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a liquid crystal display (LCD).
The present invention relates to a flat panel display device such as a crystal display (Crystal Display, liquid crystal display), and more particularly to a power-saving flat panel display device suitable for use in a small-sized computer device such as a portable personal computer or a warp that requires power saving. Things.

[0002]

2. Description of the Related Art In recent years, miniaturization of computers has been progressing. One of the major contributors to the miniaturization of computers has been flat panel displays such as LCDs and plasmas in place of CRTs (Cathode Ray Tubes). Device. Among them, LCDs have low power consumption and are widely used especially for battery-powered portable small computers. However, LCDs do not emit light as CRTs and plasma do. Therefore, there are many problems in display quality, such as low contrast.

In order to solve such a problem of the LCD, it is effective to employ a configuration in which a backlight is emitted behind a transmissive LCD. As a result, sufficient luminance can be secured, and display quality can be improved. However, since the power consumption of the backlight increases, the life of the battery is greatly reduced.

[0004] As a prior art for solving such a problem, there is, for example, one described in Japanese Patent Application Laid-Open No. 1-237810. In this technology, for example, in a situation where display is considered unnecessary, such as when the user is not performing an actual operation, the backlight is turned off and turned on when the user starts the operation. In addition, Japanese Unexamined Patent Application Publication No.
As described in Japanese Patent Application Laid-Open No. 216514, when the remaining battery life is short, there is a device that lowers the brightness of the backlight to reduce power consumption and extend the life of the battery.

[0005] However, in these conventional techniques for saving power, display quality is not ensured, and operability deteriorates in exchange for extending the life of the battery. For example, Japanese Patent Laid-Open No. 1-2
In the technique described in Japanese Patent No. 37810, the backlight can be turned on by key input. However, since the backlight is actually turned off when the user keeps the unused state for a long time, in the normal use state, the backlight is turned off. No power saving effect can be expected. Further, in the technique described in Japanese Patent Application Laid-Open No. 2-216514, since the battery life is forcibly performed when the remaining life of the battery is short, the battery must be charged in order to ensure display quality, and power saving is required. Cannot be effectively performed.

[0006]

The problem to be solved in the prior art is that the backlight is turned off or dimmed only in an emergency state such as a long unused state or a state where the battery life is short. And it is not possible to save power while ensuring display quality. An object of the present invention is to provide a power-saving flat panel display device which solves the problems of the prior art, performs power saving in a normal use state, and enables power saving while ensuring display quality. It is to be.

[0007]

To achieve the above object, a power-saving flat panel display device according to the present invention comprises:
(1) In a flat panel display device that includes a backlight that emits light and a flat panel that controls transmission of light from the backlight, and that performs display control of data, a flat panel display device that controls the entire display screen of the flat panel from the backlight. A display component determining unit that obtains a light blocking ratio that is a ratio of dots that block light; and a backlight that adjusts the brightness of the backlight based on a comparison between the light blocking ratio obtained by the display component determining unit and a predetermined value. and dimming / brightening control unit, off
A switch for inverting / forwarding the entire display screen of the rat panel
Provided with a rat panel reversal / forward rotation control unit and a backlight
The dimming / increase control unit is a flat panel inversion / forward rotation control unit.
Of the backlight according to the inversion / forward rotation switching operation
Is adjusted . ( 2 ) In the power-saving flat panel display device according to (1 ), a data counting unit that counts the number of data constituting one screen to be displayed is provided, and the backlight dimming / light increasing control unit includes:
Each time the number of data counted by the data counting unit reaches a predetermined value, the brightness of the backlight is adjusted based on the light blocking ratio. Also, ( 3 ) above (1) , if
Specifically, in the power-saving flat panel display device according to any one of (2 ) and (3 ), the backlight dimming / brightening control unit includes a predetermined value used for comparison with the light blocking ratio; Registering the degree of change in the luminance of the backlight to be adjusted in step (a), selection information as to whether or not to perform the adjustment operation of the backlight dimming / increase control section, and a predetermined value of the number of data counted by the data counting section. A condition storage unit is provided, and backlight brightness adjustment by the backlight dimming / brightening control unit is selectively performed based on conditions arbitrarily set and registered in the operation condition storage unit.

[0008]

According to the present invention, when the screen to be displayed has many portions that block the backlight, the brightness of the backlight is not so required. Therefore, the brightness of the backlight is reduced to reduce the power consumption. If the portion that blocks the backlight is small, normal backlight luminance is set to ensure display quality. As described above, by adjusting the luminance of the backlight according to the display state of the screen, it is possible to save power without deteriorating the display quality. The timing of the brightness adjustment of the backlight is performed, for example, at the time of switching between inversion and normal rotation of a screen used for improving display quality in a monochrome flat panel or the like. Also,
As a criterion for judging whether a portion of the screen to be displayed has many or less portions that block the backlight, the ratio of the portion that blocks the backlight in the entire screen is used.
Further, by making the degree of adjustment of the backlight luminance selectable, it is possible to cope with a screen having various characteristics.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a configuration according to the present invention of a power saving type flat panel display device of the present invention. In the figure, reference numeral 1 denotes a degree of the luminance of a backlight to be changed, a predetermined value of a light blocking ratio used for determining a screen to be subjected to luminance adjustment, and selection information of whether or not to perform luminance adjustment according to the present invention. The operation condition storage unit 2 for registering the information and the like controls the power value supplied to the backlight,
The backlight brightness control unit 3 that adjusts the brightness of the backlight is a display component determination unit that obtains a light blocking ratio that is a ratio of a dot that blocks light from the backlight to the entire display screen according to the present invention. According to the present invention,
A backlight dimming / light increasing control unit that controls the backlight luminance control unit 2 to adjust the luminance of the backlight based on a comparison between the light blocking ratio acquired by the display component determination unit 3 and a predetermined value; 5 is a backlight device that emits light by power supplied through the backlight luminance control unit 2,
6 is a display frame buffer for storing data to be displayed, 7 is a display control unit for converting the data stored in the display frame buffer 6 into display data corresponding to the display device, and 8 is a display screen inversion / correction. A display inversion / forward rotation switching request input unit 9 for input control of a rotation switching request is provided with: a display screen inversion / forward rotation switching request from an operator or an application program;
Reference numeral 11 denotes a flat panel that controls light blocking of the backlight device 5 based on display data. Reference numeral 12 denotes a flat panel drive that controls switching of light blocking / transmissivity of each element (dot) of the flat panel 11 based on display data. The control unit 13 is provided with a light shielding property of the flat panel drive control unit 12.
The flat panel inversion / forward rotation control unit 14 for inverting the switching of the transparency is a data counting unit that counts the number of input display data according to the present invention.

The operation of the power-saving flat panel display of this embodiment having the above-described configuration will be described below. First, display data is input to the display frame buffer 6 via the display data counting unit 14. Next, when there is a request 9 for reversing the entire display screen or switching the normal rotation from the operator or from a utility program or the like, the display reversal / reversal is performed.
The normal rotation switching request input unit 8 transmits the request to the backlight dimming / increase control unit 4 and the flat panel inversion / normal rotation control unit 1.
Notify 3 at the same time.

The flat panel inversion / forward rotation control unit 13
The display control unit 7 reads out from the display frame buffer 6,
The image information signal converted for the flat panel drive control unit 12 is received, and the image information signal is logically inverted / normally rotated in accordance with the notification from the display inversion / forward rotation switching request input unit 8 to perform the flat panel drive control unit. Send to 12. Normally, when the screen is inverted, the logic is inverted, and when the screen is inverted, no processing is performed as through. The flat panel drive control unit 12 drives the flat panel 11 using the image information signal received from the flat panel inversion / forward rotation control unit 13. In this state, an image is displayed on the flat panel 11.

On the other hand, the inversion / inversion signal notified from the display inversion / forward rotation switching request input section 8 to the backlight dimming / increase control section 4.
The backlight is controlled by the forward rotation request as follows. First, the backlight dimming / increase control unit 4 determines the ratio (color shading) of the color component that blocks the backlight on the screen to be displayed, which is calculated by the display component determination unit 3 by reading from the display frame buffer 6 by the display component determination unit 3. Percentage). The color component that blocks the backlight is usually “black” in many cases. Various techniques are conceivable for the technique of acquiring the light blocking ratio in the display component determination unit 3. For example, in the case of monochrome display, the number of dots indicating “ON” may be simply divided by the total number of dots in the display frame buffer 6. Thus, it is conceivable to weight the gradation. Since these techniques are not the main subject of the present invention, the details are omitted, but the point is that the display component determining unit 3 determines how much the screen to be displayed blocks the backlight by displaying the display frame buffer 6. By reading it out, the backlight dimming / increase control unit 4 is notified quantitatively.

The backlight dimming / increase control section 4 judges the notification from the display component judgment section 3 based on the operation conditions of the operation condition storage section 1. If it can be determined that there are many color components obstructing the backlight, it requests the backlight luminance control unit 2 to reduce the light. If it is small, it requests the backlight luminance control unit 2 to increase the light. Request to do so. The backlight luminance control unit 2 adjusts the luminance of the backlight by increasing or decreasing the power supplied to the backlight device 5 based on a request from the backlight dimming / increase control unit 4. Finally, the display image 10 by the backlight device 5 and the flat panel 11 reaches the user's eyes.

As described above, since the backlight device 5 is optimized according to the display contents of the flat panel 11,
The power consumption of the backlight can be reduced without deteriorating the display quality. The display data counting unit 1
In step 4, the received display data is sent to the display frame buffer 6, and the number of display data is counted.
For example, when the number of characters reaches 500, the counted value is reset to zero (0) and the backlight dimming / brightening control unit 4 is adjusted to adjust the luminance of the backlight according to the present invention, that is, dimming the backlight. / Issue a request to start the brightening control operation.

FIG. 2 is an explanatory diagram showing an embodiment of each operation condition registered in the operation condition storage section in FIG. In the figure, "backlight automatic dimming / lightening control processing valid / invalid information" 21 indicates whether or not to perform the backlight luminance adjustment operation according to the present invention by the backlight light dimming / lightening control unit 4 in FIG. The selection information, “the ratio of the display“ black ”component to be automatically dimmed” 22 is the backlight dimming /
A predetermined value used by the light-increase control unit 4 for comparison with the light-shielding ratio obtained from the display-component determination unit 3 in FIG.
Is the degree of change in the luminance of the backlight, which is adjusted by the backlight dimming / brightening control unit 4 in FIG. A predetermined value used by the light dimming / increase control unit 4 for comparison with the light blocking ratio obtained from the display component determination unit 3 in FIG. "25" is the degree of change in the luminance of the backlight adjusted by the backlight dimming / increase control unit 4 in FIG.

Since such operating conditions are arbitrarily set, the backlight brightness adjustment by the backlight dimming / light increasing control unit 4 shown in FIG. 1 can be selectively operated.

FIG. 3 is an explanatory diagram showing the concept of setting the operating conditions registered in the operating condition storage unit in FIG. In the figure, reference numeral 31 denotes “black on the screen to be displayed”.
Component ratio "and" 0% to 100% ".
In the present embodiment, A% in the figure is the value of the ratio corresponding to the “ratio of the display“ black ”component that automatically dims” 22 in FIG. 2, and the determination result of the display component determination unit 3 in FIG. This A% ~
If it is between 100%, the backlight dimming / increase control unit 4 in FIG. 1 performs the “automatic dimming luminance change degree” 23 in FIG.
The dimming control is performed at a value corresponding to.

Further, B% in the figure is a value of a ratio corresponding to the "ratio of display" black "component for automatic brightening" 24 in FIG. 2, and the determination result of the display component determining unit 3 in FIG. B
If it is between 0% and 0%, the backlight dimming / increase control unit 4 in FIG.
Is performed at a value corresponding to. Also, if the determination result of the display component determination unit 3 in FIG. 1 is between A% and B%,
The backlight dimming / increase control unit 4 in FIG. 1 performs control at normal luminance. Based on such a concept, the backlight dimming / increase control unit 4 of FIG. 1 replaces the backlight luminance control unit 2 of FIG. 1 with the backlight device 5 of FIG. 1 as shown in FIG. Request for power supply control to

FIG. 4 shows the backlight dimming /
6 is a flowchart illustrating an example of a processing operation according to the present invention of a light increase control unit. If there is a switching request from the display inversion / forward rotation switching request input unit 8 in FIG. 1 (step 401),
Alternatively, if the number of data from the display data counting unit 14 of FIG. 1 has reached a predetermined value (step 402), FIG.
Each operation condition is acquired from the operation condition storage unit 1 (step 403). Among the operating conditions, “backlight automatic dimming / lightening control processing valid / invalid information” 21 in FIG. 2 is valid,
If the luminance adjustment is necessary (step 404), the light blocking ratio of the display screen obtained by the display component determination unit 3 in FIG. 1 is obtained (step 405).

It is determined whether or not this light blocking ratio is larger than a predetermined value for dimming, which is the operating condition "the ratio of the display" black "component for automatic dimming" 22 in FIG. 2 (step 4).
06). If it is larger, a request is made to the backlight brightness control unit 2 of FIG. 1 to dimm the light by a predetermined degree indicated by the “degree of change in brightness for automatic dimming” 23 in the operation condition of FIG. 2 (step 407). If it is smaller, it is then determined whether or not it is smaller than a predetermined value for light increase indicated by the “ratio of display“ black ”component for automatic light increase” 24 in the operating condition of FIG. 2 (step 4).
08). If it is smaller, a request is made to the backlight brightness controller 2 of FIG. 1 to increase the brightness by a predetermined degree indicated by the "degree of change in brightness for automatic brightness increase" 25 in the operating condition of FIG. 2 (step 409). A request is made to the backlight brightness control unit 2 in FIG. 1 to set the normal brightness (step 410).

As described above with reference to FIGS. 1 to 4, in the flat panel display device of the present embodiment, the brightness of the backlight is adjusted based on the ratio of the portion of the screen to be displayed which blocks the backlight. . For example, if the entire display screen is inverted to display characters in "white", the backlight is almost blocked, and only the character portion is passed.
In such a case, the backlight is automatically dimmed.
As described above, the amount of the portion of the display screen that blocks the backlight is determined, and the brightness of the backlight is adjusted. Therefore, no matter what is displayed on the screen, the backlight that is most suitable at that time and has low power consumption is displayed. The light brightness can be automatically selected, and the power consumption of the display device can be efficiently reduced even during normal use. In addition, when the inversion or the forward rotation of the entire display screen in which the display state greatly changes occurs, the backlight is dimmed or increased. As a result, the power consumption of the backlight can be reduced without being noticed by the user.

Further, when the backlight is dimmed or increased, the ratio of the "black" display component that blocks the backlight on the current display when the dimming or the dimming is increased, and the control itself is invalidated. Since each can be selected, it can be adapted to various conditions such as a display method of a program to be used and a state around the apparatus. For example, when an AC power supply is used, it is not necessary to worry about power consumption, so that it is always possible to use the device at a high brightness. still,
The present invention is not limited to the embodiment described with reference to FIGS. 1 to 4, and can be variously modified without departing from the gist thereof.

[0023]

According to the present invention, it is possible to reduce the power consumption of a display device in a normal use state while ensuring the display quality, and to reduce the power consumption of a battery-operated type such as a portable word processor or a personal computer. It is possible to extend the usable time of the computer device and improve the performance.

[0024]

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a configuration according to the present invention of a power-saving flat panel display device of the present invention.

FIG. 2 is an explanatory diagram showing one embodiment of each operation condition registered in an operation condition storage unit in FIG. 1;

FIG. 3 is an explanatory diagram showing a concept of setting an operation condition registered in an operation condition storage unit in FIG. 1;

FIG. 4 is a flowchart showing one embodiment of a processing operation of the backlight dimming / increase control unit in FIG. 1 according to the present invention;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 operation condition storage unit 2 backlight luminance control unit 3 display component determination unit 4 backlight dimming / increase control unit 5 backlight device 6 display frame buffer 7 display control unit 8 display inversion / forward rotation switching request input unit 9 switching request Reference Signs List 10 Display image 11 Flat panel 12 Flat panel drive control unit 13 Flat panel inversion / forward rotation control unit 14 Data counting unit 21 “Backlight automatic dimming / brightening control processing valid / invalid information” 22 “Automatic dimming display“ black "Ratio of component" 23 "Degree of luminance change for automatic dimming" 24 "Ratio of display" black "component for automatic dimming" 25 "Ratio of luminance change for automatic dimming" 31 "Ratio of" black "component for displayed screen"

Claims (3)

(57) [Claims] 1. A flat panel display device, comprising: a backlight that emits light; and a flat panel that controls transmission of light from the backlight, wherein the flat panel display device controls display of data. A display component determining unit that obtains a light blocking ratio, which is a ratio of a dot that blocks light from the backlight, and a light blocking ratio obtained by the display component determining unit, based on a comparison with a predetermined value,
Backlight dimming / increase control means for adjusting the brightness of the backlight, and all display screens of the flat panel
Flat panel reversal / forward rotation switching
And a backlight dimming / increase control means.
Is the inversion / forward of the flat panel inversion / forward rotation control means.
Adjustment of the brightness of the backlight according to the switching operation
A power-saving flat panel display device. 2. The power-saving flat panel display device according to claim 1, further comprising: data counting means for counting the number of data constituting one screen of a display target, wherein the backlight dimming / light increasing control means comprises: A power-saving flat panel display device, wherein the backlight brightness is adjusted based on the light blocking ratio each time the number of data counted by the data counting means reaches a predetermined value. 3. The method of claim 1, or, in the power saving type flat panel display device according to claim 2,
The predetermined value used by the backlight dimming / enhancing control means for comparison with the light blocking ratio, the degree of change in the luminance of the backlight adjusted by the backlight dimming / enhancing control means, and the backlight dimming. Operation condition storage means for registering selection information as to whether or not to perform the adjustment operation of the light / increase control means and the predetermined value of the number of data counted by the data counting means is provided. Wherein the backlight dimming / increase control means selectively adjusts the brightness of the backlight based on the conditions registered and registered in the power-saving flat panel display device.