JP2003271106A - Display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional monitor is in a power saving state only when an image signal is silent, and cannot reduce electric power consumption in other cases, and that a monitor for broadcasting/service cannot achieve low power consumption because the monitor displays a color bar signal usually constantly even when not used in the monitor chamber of a station (in the cases where there is no effective image displayed in a state of power source on). <P>SOLUTION: Brightness of liquid crystal backlight or the gain of data of an image signal itself is lowered by automatically discriminating a specific still picture such as a color bar. Thereby, the power saving is achieved during nonuse even when the image signal is constantly inputted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display and an EL (Electrical) used in the fields of broadcasting and commercial use.
o Luminescent) Low power consumption and long life of displays.

[0002]

2. Description of the Related Art In recent years, as a display for a personal computer, a CRT display using a cathode ray tube is being replaced with a liquid crystal display which is characterized by being lightweight and thin. In the future, not only in PC displays but also in markets where CRTs were used for TVs, broadcasts, commercial use, medical use, etc., the transition from CRTs to liquid crystal displays and EL displays, which will be fully launched in the future, will take place. It is certain to be seen.

One of the characteristics of the liquid crystal display is that it consumes less power than a CRT display, but most of the power consumption is backlit (usually a cold cathode tube similar to a fluorescent lamp is used. It is consumed by. Further, due to a strong demand for higher brightness, the brightness of the backlight is increased and power consumption tends to increase.

By the way, many current CRT displays and liquid crystal displays automatically enter a power save mode when there is no video signal in order to reduce power consumption. In the power save mode, when the video signal becomes non-signal, the power of the cathode ray tube part and the liquid crystal part (or the backlight) is turned off, resulting in a black screen. With this function, power consumption can be automatically reduced when there is no video signal. For example, in a personal computer display, the power save mode can be used because the video signal supplied to the display by the personal computer is automatically set to a null signal when no key operation or mouse operation is performed for a certain period of time.

Since this function is an effective function for reducing power consumption, it is considered that similar power save control will be performed in new displays such as EL displays that will appear in the future.

[0006]

However, in the above-mentioned conventional configuration, the power saving state is not entered unless the input video signal to the display becomes a non-signal, so that the power consumption is not reduced at all. Considering the case where it is used as a broadcast / commercial display, when it is not used in the editing room or monitor room in the broadcasting station (when the power is on but there is no valid image to display. After that, it is used in the same meaning when not in use. ), The color bar signal is usually displayed at all times, so the power of the monitor is always ON and the power save mode is not entered.
Therefore, in the case of a liquid crystal display, since the backlight cannot be turned off, there is a problem that power consumption cannot be reduced. Furthermore, the most consumable component in a liquid crystal display is an expensive backlight, and there is a problem that continuous lighting with high brightness also shortens the life of the backlight. Further, even when a CRT display or a display such as an EL having no backlight is used, there is a problem that the power consumption cannot be reduced because the power save mode is not entered.

The present invention is intended to solve the above problems, and it is an object of the present invention to further reduce the power consumption of a liquid crystal display when it is not used and to extend the life of an expensive backlight.

In addition, in a display using a self-luminous element such as a CRT or EL, it is an object to reduce power consumption when not in use and extend the life of parts such as a cathode ray tube and a self-luminous element.

[0009]

In order to solve this problem, a display of the present invention according to claim 1 is characterized in that a liquid crystal display circuit, a liquid crystal backlight, a brightness control circuit of the liquid crystal backlight, and an input video signal are specified. It is characterized by having a specific still image discrimination circuit for discriminating whether or not it is a still image signal and decreasing the brightness of the liquid crystal backlight according to the discrimination result of the specific still image discrimination circuit. Can be detected to reduce the power consumption of the liquid crystal display.

The display of the present invention according to claim 2 is CR
An image display circuit using a T or self-luminous element,
A video signal gain adjustment circuit and a specific still image determination circuit that determines whether or not the input video signal is a specific still image signal are provided, and the gain of the video signal is reduced according to the determination result of the specific still image determination circuit. As a result, the power consumption can be reduced by detecting the specific still image displayed when not in use and lowering the brightness of the displayed image.

According to a third aspect of the present invention, the specific still image discrimination circuit uses the luminance signal component or the color signal component of the input video signal to detect the luminance change pattern or the color change pattern of the input specific still image. It is characterized in that the specific still image is discriminated by discriminating at least one of them, whereby the specific still image having a characteristic in luminance or color can be easily discriminated.

In order to realize the invention of claim 3, the display of the invention of claim 4 is provided inside the display.
It is characterized by including a luminance / color signal separation circuit for separating an input video signal into a luminance signal and a color signal.

According to a fifth aspect of the display of the present invention, the specific still image discriminating circuit is such that R (red) / G of an input video signal.
Using the (green) and B (blue) components, R of the input specific still image
It is characterized in that a specific still image is discriminated by detecting at least one level change pattern of a component, a G component, and a B component, thereby easily discriminating a specific still image characterized by RGB decomposed components. can do.

In order to implement the invention of claim 5, the display of the invention of claim 6 is provided inside the display.
It is characterized by including an RGB signal separation circuit for separating an input video signal into three primary colors of R component, G component and B component.

According to a seventh aspect of the display of the present invention, the specific still image discriminating circuit is capable of discriminating a plurality of types of luminance change, color change pattern, or level change pattern. It is possible to correctly determine which of the frequently used specific still images is input.

In the display according to the present invention of claim 8, the specific still image discriminating circuit is capable of discriminating a plurality of types of change patterns, and has switching means for switching the type of the change pattern to be discriminated. By setting only the specific still images used at the display installation place among the commonly used specific still images in advance, it is possible to make more accurate determination.

As described above, according to the present invention, the input signal uses a specific still image such as a color bar in a situation where a video signal is constantly input even when the display is not used, such as a broadcasting station. In this case, it is possible to automatically reduce the brightness of the backlight, reduce the brightness of the displayed image, reduce the power consumption, and prolong the life of the parts.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described. FIG. 1 is a block diagram showing a liquid crystal display which is an embodiment of the present invention. The display shown in FIG. 1 is one in which only RGB analog signals are input as in a general personal computer display. 10 is analog RGB
D / A (DA converter) for digitizing signals, 11
Is a signal processing circuit, 12 is a liquid crystal display circuit including a liquid crystal panel, 13 is a backlight for controlling the brightness according to an external analog brightness control voltage, and 14 is a brightness / color signal for separating an RGB input signal into a brightness signal and a color signal. Separation circuit, 15
Is a frame memory for storing one frame of luminance and color signals, 16 is a specific still image discriminating circuit for discriminating a specific still image based on the luminance and color signals stored in the frame memory 15,
17 is a CPU including the brightness control circuit of the backlight 13,
Reference numeral 18 denotes a D / A (DA converter) for converting the backlight control digital data output from the CPU 17 into analog and changing the backlight brightness. The specific still image determination circuit 16 has a plurality of brightness and color change patterns of specific still images registered in advance, and compares the input signal with the registered pattern to determine whether the specific still image is a specific still image.

A color bar will be described as an example of the specific still image in the following description.

FIG. 2 shows two examples of color bars often used in broadcasting stations and the like. 2A is a still image called a full-field color bar, and FIG. 2B is a still image called an SMPTE color bar. There are various types of color bars other than this. The feature of the color bar is that the brightness changes stepwise and each step is colored. In FIG. 2A, colors are attached in order of white, yellow, cyan, green, magenta, red, and blue from the left. In the case of a color bar, it is possible to determine whether or not the input signal is a color bar simply by paying attention to the change in brightness.

FIG. 3 shows the luminance change when the color bar (a) of FIG. 2 is sliced by the line A. As shown in FIG. 3, the brightness changes stepwise. Therefore, it is possible to judge whether or not the signal is a color bar by detecting and judging the stepwise change of the brightness value. The operation of the specific still image determination circuit 16 will be described with reference to FIG. 1 in which change patterns of a plurality of color bars and the like are stored in advance. In normal use, the signal input in analog RGB is D / A1.
It is digitized by 0 and is displayed on the liquid crystal display circuit 12 through the signal processing 11. Digitized RG
The B signal is simultaneously input to the luminance / color signal separation circuit 14 and separated into a luminance signal and a color signal. The signal is sequentially stored in the frame memory 15. The specific still image discrimination circuit 16 determines from the luminance / color data stored in the frame memory 15 whether or not the signal is a color bar signal.
In the case of judging by the brightness, for example, by sampling the points (a), (b), (c), and (d) in FIG. 3 on the frame memory 15, and comparing the brightness data at that time with the registered value. Determine if it is a color bar. It is also possible to simultaneously discriminate a plurality of still images by registering a plurality of change patterns in the specific still image discrimination circuit 16. Further, in the case of a color bar, it is possible to make a judgment only by the luminance signal, but the color signal can be further used as a judgment material.

When the specific still image judging circuit 16 judges that the color bar is a color bar, it informs the CPU 17. The method of notifying may be communication or may be HI / LOW of the port.

FIG. 4 shows a processing flowchart of the CPU 17. The CPU 17 checks whether the input signal is a color bar signal by monitoring the output from the specific still image discrimination circuit (S1). If it is not a color bar signal (N in S1), timer clear (S2)
D / A18 so that the backlight brightness becomes a constant brightness.
Is controlled (S3). This timer is used to reduce the brightness of the backlight only when the input signal is the color bar for a certain period of time or more, and it is intended to prevent malfunctions such as when the input signal momentarily changes to the color bar. Is.

When a color bar signal is input (Y in S1)
Starts counting up the timer (S4). If the color bar signal is continuously input, the timer overflows for a fixed time (for example, 30 seconds), and the determination is made (S5). Before the timer overflows (S5
N) of nothing, but if a certain period of time elapses and overflows (Y of S5), the backlight brightness is reduced to D
/ A18 is controlled.

When a plurality of pieces of still picture information can be registered in the specific still picture discrimination circuit 16 and the CPU 17 has a function of selecting one of them, it is also possible to select a frequently used change pattern from the CPU 17 ( (Not shown in flow chart). By doing so, it is possible to minimize malfunctions at the time of determining a specific still image in a place where the type of the still image is determined.

FIG. 5 is a second structural diagram showing a liquid crystal display which is an embodiment of the present invention. The display shown in FIG. 5 is different from the display shown in FIG. 1 in that a YC video signal (a video signal separated into a luminance signal and a color signal, which is generally called an S video signal) that is often used in a video display is inputted. There is. Besides YC video signals, composite signals and component video signals are used. 50 is Y
D / A (DA converter) for digitizing C video signal, 51 is an RGB signal separation circuit for separating a luminance signal and a color signal into RGB input signals, 52 is a frame memory for storing RGB color signals for one frame, and 53 is It is a specific still image determination circuit that determines a specific still image based on the RGB signals stored in the frame memory 52. Specific still image discrimination circuit 53
In advance, the change patterns of the R, G, and B components of a plurality of specific still images are registered in advance, and it is determined whether or not it is the specific still image by comparing the input signal with the registered pattern. Other parts are the same as in FIG.

In the liquid crystal display of FIG. 5, the color bar needs to be specified from the RGB components.
3 shows changes in RGB levels when the color bar (a) in FIG. As shown in FIG. 3, there is no stepwise change, but it can be seen that each has a characteristic change. By detecting this RGB level change pattern, it is possible to determine whether or not the signal is a color bar.

The operation of the part different from that of FIG. 1 will be described with reference to FIG. During normal use, the signals input as analog luminance / color signals are digitized by the D / A10,
After being converted into RGB signals by the RGB signal separation circuit 51,
It is displayed on the liquid crystal display circuit 12 through the signal processing 11. At the same time, the RGB signals are sequentially stored in the frame memory 52 from the RGB color signal separation circuit 51. In the specific still image discrimination circuit 53, the R stored in the frame memory 51 is stored.
It is determined from the GB data whether the signal is a color bar signal. It is possible to use all the R, G, and B components for the judgment, but 1
You may use only an ingredient. In this case, the capacity of the frame memory 52 can be reduced. If the specific still image determination circuit 53 determines that the color bar is present, it notifies the CPU 17. The processing flowchart of the CPU 17 may be the same as that in FIG.

7 and 8 are configuration diagrams showing a display using a CRT or a self-luminous element which is an embodiment of the present invention. In FIG. 7, the liquid crystal 12 and the backlight 13 of FIG. 1 are replaced with an image display circuit 70, and the backlight brightness control D / A 18 of FIG. 1 is replaced with a gain control circuit 7.
It is replaced with 1. In FIG. 8, the liquid crystal 12 and the backlight 13 of FIG. 5 are replaced with a video display circuit 70,
The backlight brightness control D / A 18 of FIG. 5 is replaced with a gain control circuit 71. Video display circuit 70
Is a device for displaying an image, which is composed of a self-luminous element such as a CRT or EL. Gain control circuit 71
Is for lowering the gain of the digital video signal in accordance with an instruction from the CPU 17, and can be composed of, for example, a multiplier of 0.5. When there is a gain reduction instruction from the CPU, the input signal is multiplied by 0.5 and output to the video display circuit 70. As a result, the brightness of the image displayed on the image display circuit 70 can be reduced to 1/2. In the case of the liquid crystal display shown in FIGS. 1 and 5, the brightness is lowered by such a configuration, but the power consumed by the backlight cannot be reduced.

FIG. 9 shows the CPU 1 in FIGS. 7 and 8.
7 shows a processing flowchart of 7. S3 of FIG. 4 is replaced by S7 and S
6 is replaced with S8. Only the parts different from FIG. 4 will be described. If it is not a color bar signal (N in S1)
Indicates to clear the timer (S2) and output the input signal to the gain control circuit 71 through. When a color bar signal is input (Y of S1), when the timer has passed a certain time and overflows (Y of S5), the gain control circuit 71 is instructed to reduce the gain of the RGB input signal, and the video display circuit 70 is instructed. Output.

From the above, in the case of a liquid crystal display,
While using the display (when displaying the required image), the backlight emits light at normal brightness, and when the color bar etc. is displayed when not in use, the backlight is automatically turned on. The brightness can be reduced.

Further, in the case of a display using a CRT or a self-luminous element, an image is displayed at normal brightness while the display is in use (when a necessary image is displayed), and when not in use. When a color bar or the like is displayed, the brightness of the image itself can be automatically reduced.

In this embodiment, the case of the color bar is shown. However, not only the color bar but also the flat image (the entire screen is a full screen of a specific color), the more complicated monoscopic image, etc., have the brightness / color or RGB components. This can be done by discriminating the characteristic part of.

In this embodiment, the analog RGB signal input is shown in FIGS. 1 and 5, and the analog luminance / color signal input is shown in FIGS. 7 and 8. However, the input can be a digital signal. The configuration may be such that various combinations of input signals are received by switching.

Further, although the backlight brightness control and the gain control are switched between two levels, that is, the normal level and the low level, the specification may be switched to a plurality of levels. Further, when the image does not have to be seen, it is possible to turn off the backlight brightness or set the image gain to 0.
It is often preferred to be able to see the color bar because it becomes impossible to distinguish it from the failure when it becomes black in broadcasting stations. In order to distinguish it from a failure, an indicator lamp such as a light emitting diode is provided at a position visible from the outside such as the front of the display, and when the display is not used, the backlight brightness is turned off and the image gain is set to 0.
Alternatively, the indicator lamp may be turned on. In addition to the normal display part of the display, a small display part is provided, and when the display is not used,
The backlight brightness may be turned off, the video gain may be set to 0, and a message indicating that the power saving mode is entered may be displayed on the display unit as a message so that the failure can be distinguished.

[0036]

As described above, according to the present invention, particularly in a broadcast / commercial display, even when a specific still image signal such as a color bar is always input when not in use, a still image By detecting the change pattern of the brightness component / color component and the change pattern of the RGB component and automatically performing the backlight control and the signal gain control, it is possible to reduce the backlight brightness and the brightness of the image. The great effect that unnecessary power consumption can be reduced is obtained. Especially in broadcasting stations, many monitors are in constant operation, so the power saving effect is great.

Further, the life of the backlight, the display element and the like can be extended, which is advantageous in terms of maintenance and cost of parts.

Furthermore, when a specific still image is detected, not only the power is turned off as in the conventional power save mode, but also the backlight brightness and the image brightness are reduced, so that the screen becomes black. There is also an effect that the image itself can be visually confirmed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a liquid crystal display which is an embodiment of the present invention.

FIG. 2 is a diagram showing an example of two color bars often used in broadcasting stations and the like.

FIG. 3 is a diagram showing a change in luminance when the color bar (a) in FIG. 2 is sliced by a line A.

FIG. 4 is a processing flowchart of the CPU 17.

FIG. 5 is a second configuration diagram showing a liquid crystal display which is an embodiment of the present invention.

FIG. 6 is a RGB level change when the color bar (a) of FIG. 2 is sliced by the line A.

FIG. 7 is a configuration diagram showing a display using a CRT or a self-luminous element which is an embodiment of the present invention.

FIG. 8 is a configuration diagram showing a display using a CRT or a self-luminous element which is an embodiment of the present invention.

FIG. 9 is a processing flowchart of the CPU 17.

[Explanation of symbols]

10 D / A 11 Signal processing circuit Liquid crystal display circuit including 12 13 Backlight 14 Luminance / color signal separation circuit 15 frame memory 16 Specific still image discrimination circuit 17 CPU 18 D / A 50 D / A 51 RGB signal separation circuit 52 frame memory 53 Specific still image discrimination circuit 70 Video display circuit 71 Gain control circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 642 G09G 3/20 642Z 5C082 650 650L 3/34 3/34 J 5/00 550 5/00 550A H04N 5/66 H04N 5/66 AF terms (reference) 2H091 FA41Z GA11 LA30 2H093 NC14 NC24 NC29 NC42 ND39 5C006 AA01 AA02 AA22 AF45 AF51 AF52 AF53 AF61 AF69 BB29 EA01 A12 ABB A13A12 A12 A12 A12 A12 A12 A12 A12 A12 A12 A12 A12 A12 A11 A12 A12 A12 A11 A12 A12 BB05 DD26 EE17 EE28 JJ02 JJ04 JJ07 5C082 AA01 BA12 BA34 BA41 BD01 BD02 CA11 CA81 CB01 MM03

Claims (8)

[Claims] 1. A liquid crystal display circuit, a liquid crystal backlight,
It is equipped with a brightness control circuit for the LCD backlight and a specific still image determination circuit that determines whether or not the input video signal is a specific still image signal. Characteristic display. 2. An image display circuit using a CRT or a self-luminous element, a gain adjustment circuit for an image signal, and a specific still image determination circuit for determining whether or not an input image signal is a specific still image signal. A display characterized in that the gain of a video signal is reduced according to the determination result of a still image determination circuit. 3. The specific still image discriminating circuit discriminates at least one of a luminance change pattern and a color change pattern of an input specific still image by using a luminance signal component or a color signal component of an input video signal. The display according to any one of claims 1 and 2, wherein the specific still image determination is performed according to. 4. The display according to claim 3, further comprising a luminance / color signal separation circuit for separating an input video signal into a luminance signal and a color signal. 5. The specific still image discrimination circuit uses the R (red), G (green), and B (blue) components of the input video signal to determine the R component, G component, and B component of the input specific still image. At least one of
The display according to claim 1 or 2, wherein the specific still image determination is performed by determining one or more level change patterns. 6. The display according to claim 5, further comprising an RGB signal separation circuit for separating an input video signal into three primary colors of R component, G component and B component. 7. The display according to claim 1, wherein the specific still image discrimination circuit is capable of discriminating a plurality of types of luminance change, color change pattern, or level change pattern. 8. The specific still image discriminating circuit is capable of discriminating a plurality of types of change patterns, and has switching means for switching the type of the change pattern to be discriminated. display.