JP2004325853A - Method of preventing image persistence of liquid crystal monitor, liquid crystal monitor provided with image persistence preventing function, and computer provided with image persistence preventing function of liquid crystal monitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of preventing a long-term image persistence of a liquid crystal monitor, the liquid crystal monitor capable of preventing the image persistence and a computer capable of preventing the image persistence of the liquid crystal monitor. <P>SOLUTION: The method is for preventing an image persistence of the liquid crystal monitor caused by the deviation of ionic impurities inside the liquid crystal after displaying the same image for a long period of time, and it is characterised in that, in the case that there is no change in the image for a prescribed period of time, a gradation inverted image obtained by inverting the gradation of the displayed image is displayed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for preventing burn-in of a liquid crystal monitor that can prevent burn-in, a liquid crystal monitor that can prevent burn-in, and a computer that can prevent burn-in of a liquid crystal monitor.
[0002]
[Prior art]
2. Description of the Related Art It has been known that burn-in occurs when a CRT monitor displays the same image for a long time.
The burn-in of the CRT monitor is caused by the fact that the characteristics are deteriorated due to the phosphor being hit by the electron beam for a long time.
Therefore, as a measure to prevent burn-in of the CRT monitor, a screen saver that displays a slightly darker image that is different from the displayed image and has a motion when there is no input for a certain period of time or a power saving standby mode A known method is known (for example, see Patent Document 1).
This patent document 1 discloses a plurality of power saving standby modes having a plurality of power saving levels according to a time during which no input is made. However, many monitors now enter a single power-saving level power-saving standby mode in response to a power-saving standby signal (stopping transmission of a horizontal or vertical synchronization signal) from a computer.
[0003]
On the other hand, it is known that burn-in can occur on a liquid crystal monitor.
Hereinafter, the burn-in of the liquid crystal monitor will be briefly described.
LCD monitor burn-in includes short-term burn-in and long-term burn-in.
It is said that short-term burn-in occurs because the residual DC component of the AC voltage applied to the liquid crystal panel causes polarization in the alignment film in the liquid crystal panel.
On the other hand, the reason for the occurrence of long-term burn-in is that the residual DC component of the AC component applied to the liquid crystal panel differs in size between the dark and bright areas on the screen, so that the liquid crystal originally It is considered that the mixed ionic impurities are unevenly distributed and the characteristics of a portion where a large amount of impurities are collected are deteriorated.
Since the long-term burn-in is caused by the concentration of ionic impurities, a symptom such as partial darkening occurs.
[0004]
Patent Document 2 discloses a method for alleviating short-term burn-in of the above-described burn-in of a liquid crystal monitor.
Japanese Patent Laid-Open No. 2005-133,056 discloses a technique for controlling pixels constituting a liquid crystal panel to randomly display black regardless of an image signal.
[0005]
[Patent Document 1]
Japanese Unexamined Patent Publication No. Hei 8-508831
[Patent Document 2]
JP 2000-98980 A
[0006]
[Problems to be solved by the invention]
According to the control method disclosed in Patent Document 2, short-term burn-in of the liquid crystal monitor can be prevented.
However, in such a conventionally known technique, although the short-term burn-in can be prevented by eliminating the polarization for each pixel, long-term burn-in caused by the movement of ionic impurities in the liquid crystal can be prevented. It does not contribute to prevention at all.
For this reason, there has been a problem that a method that can prevent long-term burn-in is desired.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a method for preventing a long-term burn-in of a liquid crystal monitor, a liquid crystal monitor capable of preventing a burn-in, and a computer capable of preventing a burn-in of the liquid crystal monitor. And to provide.
[0008]
[Means for Solving the Problems]
According to the method for preventing image sticking of a liquid crystal monitor according to the present invention, after displaying the same image for a long time, a method for preventing image sticking of the liquid crystal monitor caused by biasing of ionic impurities in the liquid crystal, and When there is no change in the image, a grayscale inversion image obtained by grayscale inversion of the displayed image is displayed.
By employing this method, the magnitude of the residual direct current component of the voltage applied to the liquid crystal panel due to the image displayed for a long time is completely reversed on the screen. In other words, the ionic impurities moving based on the magnitude of the residual DC component now move in the opposite direction. For this reason, it is possible to prevent long-term burn-in caused by the bias of the ionic impurities.
[0009]
Further, according to the method for preventing burn-in of a liquid crystal monitor according to the present invention, after displaying the same image for a long time, it is a method of preventing burn-in of a liquid crystal monitor caused by bias of ionic impurities in the liquid crystal. When there is no change in the time image, the whole white image or the whole black image is displayed.
According to this method, the voltage is applied so that the residual DC component of the voltage applied to the liquid crystal panel based on the image displayed for a long time is eliminated. For this reason, the ionic impurities that have been biased can be dispersed, and long-term burn-in caused by the bias of the ionic impurities can be prevented.
[0010]
ADVANTAGE OF THE INVENTION According to the liquid crystal monitor which has the burn-in prevention function concerning this invention, in the liquid crystal monitor which receives the image signal from a computer and displays an image based on the said image signal, from input means, such as a keyboard of a computer, a pointing device, etc. When the power saving standby signal transmitted from the computer is received when there is no input for a predetermined time, the image displayed immediately before receiving the power saving standby signal is grayscale inverted, and the grayscale inverted grayscale is inverted. It is characterized in that control is performed so as to display a toned image.
With this configuration, when a predetermined signal is input from the computer, an image obtained by inverting the gradation of the image displayed immediately before is displayed, so that the dark part and the bright part in the image displayed so far are reversed. . For this reason, the magnitude of the residual direct current component of the voltage applied to the liquid crystal panel due to the image displayed for a long time has a completely opposite arrangement on the screen. In other words, the ionic impurities moving based on the magnitude of the residual DC component now move in the opposite direction. For this reason, it is possible to prevent long-term burn-in caused by the bias of the ionic impurities.
[0011]
Further, a backlight as a light source may be provided, and when displaying the gradation-reversed image, the backlight may be controlled to be turned off or dimmed.
According to this, the user is not using the computer while the image whose grayscale is inverted is displayed, so that power consumption by the backlight can be suppressed during this time.
[0012]
According to the liquid crystal monitor having the burn-in prevention function according to the present invention, in a liquid crystal monitor that receives an image signal from a computer and displays an image based on the image signal, input means such as a computer keyboard and a pointing device are provided. When a power saving standby signal transmitted from the computer is received when there is no input from the computer for a predetermined time, an all-white image or an all-black image is generated, and the generated all-white image or the all-black image is displayed. It is characterized in that
With this configuration, the voltage is applied so that the residual DC component of the voltage applied to the liquid crystal panel based on the image displayed for a long time is eliminated. For this reason, the ionic impurities that have been biased can be dispersed, and long-term burn-in caused by the bias of the ionic impurities can be prevented.
[0013]
Note that a backlight as a light source is provided, and when displaying the entire white image or the entire black image, if the backlight is controlled to be turned off or dimmed, while the user is not using the computer, Power consumption by the backlight can be suppressed.
[0014]
According to the computer having the function of preventing burn-in of a liquid crystal monitor according to the present invention, a control unit, input means such as a keyboard and a pointing device, an image signal generating unit for generating an image signal to be displayed on the liquid crystal monitor, and an image signal generating unit And a signal output unit for transmitting the image signal generated by the unit to the liquid crystal monitor, wherein the image signal is input, and the input / output signal is inverted to generate a gray scale inverted image signal. A negative conversion unit, wherein when there is no input from the input unit for a predetermined period of time, the control unit inputs the image signal currently output to the liquid crystal monitor to the positive / negative conversion unit and performs grayscale inversion. Controlling to generate an image signal and to output a tone-reversed image signal to a liquid crystal monitor via the image signal generation unit and the signal output unit. To have.
By adopting this configuration, an image in which the gradation of the image displayed immediately before is inverted on the liquid crystal monitor is displayed, so that the dark part and the bright part in the image displayed so far are reversed. For this reason, the magnitude of the residual direct current component of the voltage applied to the liquid crystal panel due to the image displayed for a long time has a completely opposite arrangement on the screen. In other words, the ionic impurities moving based on the magnitude of the residual DC component now move in the opposite direction. For this reason, it is possible to prevent long-term burn-in caused by the ionic impurities of the liquid crystal monitor offset.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First Embodiment of LCD Monitor)
First, FIG. 1 is a block diagram showing the internal configuration of the first embodiment of the liquid crystal monitor.
The outline of the operation of the liquid crystal monitor 20 according to the first embodiment is as follows. When the computer is not operated for a predetermined time and a power saving standby signal is received from the computer, the level of the display image displayed immediately before is inverted. It is characterized in that by displaying a toned image, long-term burn-in can be prevented.
[0016]
The liquid crystal monitor 20 includes a liquid crystal module 30 connected to a computer (not shown) and displaying an image signal input from the computer.
The liquid crystal module 30 has a driving unit 23, a liquid crystal panel 29 in which electrodes and an alignment film are disposed on a glass substrate, and a liquid crystal panel 29 disposed on the back side of the liquid crystal panel 29 to serve as a light source. And a backlight 31 to be driven.
[0017]
The signal input unit 22 is a part connected to a computer via a cable, and receives an image signal a and a synchronization signal b (including a horizontal synchronization signal and a vertical synchronization signal) from the computer.
The image signal a is output from the signal input unit 22 to the image signal processing unit 24. The image signal processing unit 24 converts the input image signal into a digital signal, adjusts the contrast and the like, and converts it into an image signal c to be displayed on the liquid crystal module 30.
A buffer memory 26 is connected to the image signal processing unit 24, and temporarily stores the image signal c before outputting the image signal c to the liquid crystal module 30.
[0018]
On the other hand, the synchronization signal b is input to the synchronization signal processing unit 28.
When a synchronization signal is superimposed on the image signal a, the image signal a is input to the synchronization signal processing unit 28, where the synchronization signal is separated.
The synchronization signal processing unit 28 performs operations such as adjusting the polarity of the input synchronization signal and shaping the waveform.
The synchronization signal d whose waveform has been shaped by the synchronization signal processing unit 28 is input to the signal determination processing unit 34 of the control unit 32 including a CPU and the like.
[0019]
The signal discrimination processing unit 34 discriminates the presence or absence of the synchronization signal d, and performs control such as setting to a power saving standby mode based on the presence or absence of the horizontal / vertical synchronization signal. Here, the power saving standby mode means that when the computer has not been used for a predetermined period of time (when no input has been made on a keyboard, a pointing device, or the like for a predetermined period of time), all except for the synchronization signal processing unit 28 and the control unit 32 This is a mode in which power supply to the circuit is stopped.
[0020]
Further, the control unit 32 can control the backlight power supply circuit 27 so that the backlight 31 provided in the liquid crystal module 30 can be turned on and off, and further, can be dimmed or increased. A backlight control unit 37 is provided. The backlight control unit 37 outputs a backlight control signal f to control the backlight power supply circuit 27 of the backlight 31.
[0021]
An operation unit 38 is connected to the control unit 32, and the contrast, brightness, vertical position, horizontal position, and the like of the monitor display can be adjusted by a user operation.
It is preferable that the operation unit 38 can be operated according to the contents displayed on the liquid crystal module 30 as an on-screen display by using switches arranged on the front side of the liquid crystal monitor 20 or the like.
[0022]
Further, the buffer memory 26 is provided with a positive / negative conversion unit 36, which can create data in which the gradation of the image signal stored in the buffer memory 26 is inverted.
In the present embodiment, when the signal discrimination processing unit 34 detects that one of the horizontal and vertical synchronization signals out of the synchronization signal d is no longer input, the control unit 32 is stored in the buffer memory 26. The image signal is controlled to be output to the positive / negative conversion unit 36.
The image signal stored in the buffer memory 26 is generated as a grayscale inverted image signal e whose grayscale is inverted by the positive / negative conversion unit 36, and is input to the image signal processing unit 24.
Then, the image signal processing unit 24 outputs the grayscale inverted image signal e to the liquid crystal module 30 instead of the image signal c, and causes the liquid crystal panel 29 to display the grayscale inverted image.
[0023]
The grayscale inversion here need not be strictly performed for each pixel constituting the liquid crystal panel 29. This is because the long-term burn-in of the liquid crystal monitor does not clearly burn even a fine character portion, but is a darkening that occurs due to a partial offset of ionic impurities as described in the related art.
[0024]
Here, the operation of the control unit 32 in the conventional power saving standby mode will be described.
In a normal computer operation, a synchronization signal is used as a trigger when shifting to the power saving mode. That is, when one of the horizontal and vertical synchronizing signals out of the synchronizing signals d is no longer input, control is performed so as to switch to the power saving standby mode.
For example, when the horizontal synchronization signal is no longer input to the signal discrimination processing unit 34 of the control unit 32 of the liquid crystal monitor 20, the power to all the circuits except the synchronization signal processing unit 28 and the control unit 32 is cut off to save power. Enter mode.
[0025]
The operation of the liquid crystal monitor for preventing burn-in according to the present embodiment will be described with reference to the flowchart of FIG.
In step S100, the signal determination processing unit 34 constantly checks whether or not the synchronization signal d has been input from the computer.
While both the horizontal and vertical synchronizing signals among the synchronizing signals d are being input, the control unit 32 converts the image signal a received to the image signal processing unit 24 into the image signal c as the image signal c. (Step S102).
On the other hand, when the signal discrimination processing unit 34 detects that either the horizontal or vertical synchronization signal of the synchronization signal d has not been input, the control unit 32 transmits the latest image signal stored in the buffer memory 26. Is output to the positive / negative conversion unit 36, and the positive / negative conversion unit 36 is controlled to output the generated gradation inversion image signal e to the image signal processing unit 24 (step S104). ).
[0026]
Subsequently, the control unit 32 performs the gradation inversion to display the gradation inversion image signal e generated by the positive / negative conversion unit 36 instead of the image signal a input to the image signal processing unit 24. An instruction is issued to output the image signal e to the liquid crystal module 30 (step S106).
[0027]
Note that the backlight control unit 37 of the control unit 32 outputs a backlight control signal f to the backlight power supply circuit 27 to turn off or dimming the backlight 31, and turns off the backlight 31. Alternatively, control is performed such that the light is dimmed (step S108).
Since the backlight consumes 50 to 90% of the total power consumption of the liquid crystal monitor, turning off or dimming the backlight is effective as an effect for reducing the power consumption of the liquid crystal monitor.
In this manner, the voltage for displaying an image in which the gradation of the image displayed so far is inverted, that is, an image in which the bright portion becomes dark and the dark portion becomes bright, is applied to the liquid crystal panel 29. Is applied.
[0028]
After controlling to output the tone-reversed image signal e, when the signal discrimination processing unit 34 detects that both the horizontal and vertical synchronizing signals of the synchronizing signals d are input from the computer (step S1). S110) The control unit 32 proceeds to step S112, and converts the image signal a into an image so that the image signal a input to the image signal processing unit 24 is displayed instead of the grayscale inversion image signal e. It is instructed to output the signal c to the liquid crystal module 30.
Further, the control unit 32 outputs a backlight control signal f to the backlight power supply circuit 27 to return the brightness of the backlight 31 to the original state (Step S114).
Then, the liquid crystal monitor 20 returns to the original state where the normal image signal a is displayed.
[0029]
On the other hand, when one of the horizontal and vertical synchronizing signals of the synchronizing signal d is not input in step S110, the liquid crystal module 30 receives the image until the synchronizing signal d is input and immediately before the synchronizing signal d is interrupted. A tone-reversed image obtained by inverting the tone of a signal is continuously displayed.
[0030]
As described above, when the grayscale-inverted image signal is displayed, the reverse residual DC component is generated by the grayscale-inverted image, and the uneven distribution of the ionic impurities due to the long-time display of the normal image signal is eliminated. If is repeated for an unnecessarily long time, the ionic impurities may be unevenly distributed in the opposite position.
Therefore, the control unit 32 measures the time from when any one of the horizontal and vertical synchronizing signals of the synchronizing signal d is not input by the signal discriminating processing unit 34, and when a predetermined time has elapsed, the signal processing unit 34 It is preferable to control the image signal processing unit 24 so as to automatically change the amplitude of the toned image signal and the DC component included in the signal.
[0031]
(Second embodiment of liquid crystal monitor)
Next, a second embodiment of the liquid crystal monitor of the present invention will be described.
In the first embodiment, the configuration is such that an image whose gradation is inverted is displayed in order to apply a residual DC component relatively opposite to the residual DC component by the fixed image display over a long period of time.
It has been found that a method different from such a configuration has an effect of preventing image sticking due to fixed image display in the daytime by applying a liquid crystal drive voltage to the entire surface of the liquid crystal panel at night, for example.
Therefore, in the second embodiment of the liquid crystal monitor, when the computer is not operated for a predetermined time, for example, at night, a normally black liquid crystal panel (all black when no voltage is applied to the liquid crystal panel 29) When a white display voltage is applied and a normally white liquid crystal panel (all white when no voltage is applied to the liquid crystal panel 29), a full black display voltage is applied to prevent long-term burn-in.
[0032]
FIG. 3 is a block diagram showing the internal structure of the second embodiment of the liquid crystal monitor. The same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
A pattern generator 42 is connected to the image signal processor 24 of the liquid crystal monitor 20 in the second embodiment.
The pattern generated by the pattern generation unit 42 is an entire white image signal or an entire black image signal. Whether to generate a full white image signal or a full black image signal is to generate a full white image signal for a normally black liquid crystal panel and to generate a full black image signal for a normally white liquid crystal panel. It is good to do.
[0033]
In the present embodiment, when the signal discrimination processing unit 34 detects that one of the horizontal and vertical synchronizing signals of the synchronizing signal d is no longer input, the control unit 32 causes the pattern generating unit 42 to output an entire white image. A signal or an entire black image signal g is instructed to be generated, and the generated entire white image signal or the entire black image signal g is input to the image signal processing unit 24.
The image signal processing unit 24 outputs the whole white image signal or the whole black image signal g to the liquid crystal module 30 instead of the image signal c, and causes the liquid crystal panel 29 to display the whole white image or the whole black image.
[0034]
Subsequently, the operation of the liquid crystal monitor of the present embodiment will be described based on the flowchart of FIG. It is assumed that the liquid crystal monitor described here is normally black.
In step S200, the signal determination processing unit 34 constantly checks whether or not the synchronization signal d has been input from the computer.
While both the horizontal and vertical synchronizing signals among the synchronizing signals d are being input, the control unit 32 converts the image signal a received to the image signal processing unit 24 into the image signal c as the image signal c. (Step S202).
On the other hand, when the signal determination processing unit 34 determines that either the horizontal or vertical synchronization signal of the synchronization signal d has not been input, the control unit 32 causes the pattern generation unit 42 to generate the entire white image signal g, Control is performed so as to output to the image signal processing unit 24 (step S204).
[0035]
Subsequently, the control unit 32 outputs the full white image signal g to the liquid crystal module 30 in order to display the full white image signal g instead of the image signal a input to the image signal processing unit 24. (Step S206).
[0036]
The control unit 32 outputs a backlight control signal f to the power supply circuit 27 of the backlight 31 to turn off or dimm the backlight 31 in order to turn off or dimming the backlight 31. Control is performed (step S208).
In this way, an entire white image is displayed on the liquid crystal module 30.
[0037]
After controlling to output the entire white image signal g, when the signal determination processing unit 34 detects that both the horizontal and vertical synchronization signals of the synchronization signal d have been input from the computer (step S210). ), The control unit 32 proceeds to step S212, and converts the image signal a into the image signal c so that the image signal a input to the image signal processing unit 24 is displayed instead of the entire white image signal g. Is output to the liquid crystal module 30.
Further, the control unit 32 outputs a backlight control signal f to the backlight power supply circuit 27 to return the brightness of the backlight 31 to the original state (Step S214).
Then, the liquid crystal monitor 20 returns to the original state where the normal image signal a is displayed.
[0038]
On the other hand, if any of the horizontal and vertical synchronization signals among the synchronization signals d is not input in step S210, the liquid crystal module 30 continues to display the entire white image until the synchronization signal d is input.
[0039]
Note that the method of applying the entire liquid crystal driving voltage as in the above-described second embodiment has a smaller effect of preventing image sticking than the method of applying the gradation inversion signal of the first embodiment.
Therefore, in order to obtain an intermediate effect between the effects of the first embodiment and the effects of the second embodiment, a configuration may be adopted in which a full white image and a full black image are alternately displayed at predetermined time intervals. Good.
For example, in the case of a normally black liquid crystal monitor, control is performed so that an entire white image is displayed for 10 minutes, and then an entire black image is displayed for 5 minutes.
[0040]
In the above-described liquid crystal monitor, the means for preventing burn-in is executed by itself. However, these operations may be executed by a computer that controls the liquid crystal monitor.
Therefore, next, a computer for preventing burn-in of the liquid crystal monitor will be described.
[0041]
(Embodiment of computer)
The computer referred to here is a general-purpose computer generally used.
FIG. 5 shows the internal configuration of the computer.
The computer 50 includes a control unit 52 including a CPU and a semiconductor memory, a storage unit 54 such as a hard disk, and an input unit 57 such as a keyboard 55 and a pointing device 56 for a user to input information.
The computer 50 includes an image signal generation unit 58 having an image memory 59 to generate an image signal, a signal output unit 60 that outputs the generated image signal to a liquid crystal monitor, and a control unit 52. A positive / negative conversion unit 62 for generating a grayscale inverted image signal in which the grayscale of the image signal is inverted in order to prevent burn-in of the liquid crystal monitor is provided.
These components are connected to one another via an internal bus 61.
[0042]
The control unit 52 realizes the screen saver unit 64 by reading and executing the screen saver program 63 stored in the storage unit 54.
When there is no input from the input unit 57 for a predetermined time (adjustable by the user), the screen saver unit 64 generates a screen saver image signal having a motion different from the currently displayed image in the image signal generation unit 58, It has a function of outputting to a liquid crystal monitor via the output unit 60. Various types of screen saver images are known, such as images imitating space travel and images in which predetermined characters move on the screen.
[0043]
In the liquid crystal monitor, it is impossible to prevent burn-in with such a screen saver image. Therefore, the screen saver means of the computer of the present embodiment outputs an image signal for preventing burn-in instead of the above-described normal screen saver image. The feature is that it can be done.
That is, when the input from the input unit 57 has not been performed for a predetermined time (adjustable by the user), the screen saver unit 64 causes the image signal to be input to the positive / negative conversion unit 62 to generate a grayscale inverted image signal. The tone-reversed image signal is input to the image signal generator 58 and output from the signal output unit 60 to the liquid crystal monitor.
[0044]
As described above, since the tone-reversed image signal is transmitted from the computer, long-term burn-in of the liquid-crystal monitor can be prevented even if there is no means for generating the tone-reversed image signal on the liquid crystal monitor. .
[0045]
It should be noted that the screen saver means 64 may be provided so as to be able to select whether to output a screen saver image signal or a grayscale inverted image signal by setting by the user.
Further, after the input from the input means 57 is interrupted, the conventional screen saver image signal is output after the first predetermined time has elapsed, and after the second predetermined time has elapsed after the screen saver image signal has been output, the gradation inverted image signal is output. You may make it.
[0046]
If the tone-reversed image signal is continuously displayed on the liquid crystal monitor for a long time, the bias of the ionic impurities due to the long-time display of the normal image is eliminated. It is also conceivable that ionic impurities are offset to the opposite position due to the occurrence of the ionic impurities.
Therefore, the screen saver unit 64 of the computer 50 automatically adjusts the contrast and brightness of the grayscale inverted image when a predetermined time has elapsed after outputting the grayscale inverted image signal so that the same grayscale inverted image is not displayed for a long time. The positive / negative conversion means 62 may be controlled so as to change the position.
[0047]
Note that the concept described as “prevention of burn-in” in this specification includes both concepts of eliminating a burn-in that has already occurred and preventing a burn-in that has not yet occurred. Shall be.
[0048]
Although various preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. .
[0049]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the burn-in prevention method of the liquid crystal monitor, the liquid crystal monitor having the burn-in prevention function, and the computer having the burn-in prevention function of the liquid crystal monitor according to the present invention, an image in which the gradation of the image displayed so far is inverted is displayed. Thereby, the ionic impurities moving based on the magnitude of the residual DC component can be moved in the opposite direction, thereby preventing long-term burn-in.
Also, by displaying a full white image or a full black image, a voltage is applied such that the residual direct current component is uniformed, so that the ionic impurities that have been biased are dispersed, and the ionic impurities are generated due to the bias. Long-term seizure can be prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a liquid crystal monitor according to a first embodiment of the present invention.
FIG. 2 is a flowchart illustrating a burn-in prevention operation of the liquid crystal monitor illustrated in FIG. 1;
FIG. 3 is a block diagram illustrating a second embodiment of the liquid crystal monitor according to the present invention.
FIG. 4 is a flowchart illustrating an operation for preventing burn-in of the liquid crystal monitor illustrated in FIG. 3;
FIG. 5 is a block diagram showing an embodiment of an LCD monitor burn-in prevention computer according to the present invention.
[Explanation of symbols]
20 LCD monitor
22 signal input section
23 Drive
24 Image signal processing unit
26 buffer memory
27 Backlight power supply circuit
28 Synchronous signal processing unit
29 LCD panel
30 LCD module
31 Backlight
32 control unit
34 signal discrimination processing unit
36 Positive / negative converter
37 Backlight control unit
38 Operation unit
42 Pattern generator
50 Computer
52 control unit
54 storage means
55 keyboard
56 pointing device
57 Input means
58 Image signal generator
59 Image memory
60 signal output section
61 Internal bus
62 Positive / negative conversion means
63 Screen Saver Program
64 screen saver means
a Image signal
b Sync signal
c Image signal
d Sync signal
e Tone inverted image signal
f Backlight control signal
g Full black image signal, full white image signal

Claims (7)

After displaying the same image for a long time, it is a method of preventing image sticking of a liquid crystal monitor caused by ionic impurities in the liquid crystal being offset,
A method for preventing burn-in of a liquid crystal monitor, characterized in that when there is no change in the image for a predetermined period of time, a gradation-reversed image is displayed by reversing the gradation of the displayed image. After displaying the same image for a long time, it is a method of preventing image sticking of a liquid crystal monitor caused by ionic impurities in the liquid crystal being offset,
A method for preventing image sticking of a liquid crystal monitor, wherein an entire white image or an entire black image is displayed when there is no change in the image for a predetermined time. In a liquid crystal monitor that receives an image signal from a computer and displays an image based on the image signal,
When the power saving standby signal transmitted from the computer is received when there is no input from the input means such as the keyboard or the pointing device of the computer for a predetermined time, the image displayed immediately before the reception of the power saving standby signal is received. A liquid crystal monitor having a burn-in prevention function, characterized in that the image is controlled so as to display a gradation-reversed image in which the gradation is reversed. A backlight as a light source is provided,
4. The liquid crystal monitor having a burn-in prevention function according to claim 3, wherein when displaying the gradation-reversed image, the backlight is controlled to be turned off or dimmed. In a liquid crystal monitor that receives an image signal from a computer and displays an image based on the image signal,
When an input from input means such as a keyboard or a pointing device of a computer has not been performed for a predetermined time, when a power saving standby signal transmitted from the computer is received, an entire white image or an entire black image is generated, and the generated entire image is generated. A liquid crystal monitor having a burn-in prevention function, wherein the liquid crystal monitor is controlled to display a white image or an entire black image. A backlight as a light source is provided,
6. The liquid crystal monitor according to claim 5, wherein when displaying the whole white image or the whole black image, the backlight is controlled to be turned off or dimmed. A control unit;
Input means such as a keyboard and a pointing device,
An image signal generator for generating an image signal to be displayed on the liquid crystal monitor;
A signal output unit for transmitting an image signal generated by the image signal generation unit to a liquid crystal monitor,
An image signal is input, and a positive / negative conversion unit that generates a grayscale inverted image signal obtained by inverting the grayscale of the input image signal;
When there is no input from the input unit for a predetermined time, the control unit inputs the image signal currently output to the liquid crystal monitor to the positive / negative conversion unit to generate a grayscale inverted image signal, A computer having a function of preventing burn-in of a liquid crystal monitor, wherein the computer controls so as to output a gradation inversion image signal to a liquid crystal monitor via an image signal generation unit and the signal output unit.

Images