JP2003274315A - Device and method for image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a sticking phenomenon that a display part has and to display a video signal without any disorder. <P>SOLUTION: On the basis of synchronizing signals of the video signal, a time measurement part 14 measure a time and based upon its value, a display phase adjustment part 13 adjusts the phases of the synchronizing signals to display a picture at a display part 16. In that case, the phases of the synchronizing signals are shifted alternately in opposite directions so that the phase shift quantities periodically increase and decrease with the time from a phase- unadjusted state. Consequently, a display position is integrated with the time to suppress sticking and display the picture without any visual disorder. <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 an image display device and an image display method, and particularly to an image display device suitable for application to a wide television receiver or the like capable of displaying video signals having different aspect ratios. Regarding image display method.

[0002]

2. Description of the Related Art In recent years, in television broadcasting, a wide screen has been promoted along with an improvement in image quality of a video signal, and a video signal having a screen configuration of 16: 9 has been replaced with a conventional aspect ratio of 4: 3. The applied programs are becoming rare.

Along with this, television receivers for receiving broadcast programs, which are equipped with display means having a screen with an aspect ratio of 16: 9, are becoming more popular. In a case where a 4: 3 video signal is displayed on a television receiver equipped with a display unit corresponding to a 16: 9 video signal, an area where the image is not displayed at the left and right edges of the screen and is not used at all Will occur.

As described above, when a state where a part of the screen of the display means is not used continues for a long time, a difference in display efficiency occurs between a projected area and a non-projected area, and a video signal is displayed using the entire screen. In this case, there is a problem that a so-called burning phenomenon occurs in which the brightness is changed at the boundary between these areas and the screen becomes unsightly.

When the screen of the display means is not used,
This also occurs when a 16: 9 video signal is displayed on a 4: 3 screen, and the upper and lower edges of the screen are not used,
Similarly, if the image is displayed in that state for a long time, the boundary between the non-imaged area and the imaged area becomes conspicuous.

Such a burning phenomenon also occurs in a CRT (cathode ray tube), but it is more likely to occur in a PDP (plasma display panel), which has recently attracted attention as a display means, and various countermeasures have been considered. There is.

Conventionally, in order to prevent image sticking, when displaying video signals having different aspect ratios with respect to the screen configuration of the display means, the display position of the screen is shifted when the power of the television receiver is turned on or when the channel is switched. Or
Alternatively, measures such as so-called smoothing are performed on the boundary between the projection area and the non-projection area so that the brightness gradually decreases from the projection area to the non-projection area (Japanese Patent Laid-Open No. 2001-175212). No.).

[0008] However, the former has no effect when watching the same channel continuously for a long time, and even if the display position of the video signal is changed at an appropriate timing, there are several patterns of display positions. Therefore, it was not always possible to suppress the baking sufficiently. The latter can be expected to have some effects, but has a problem that the circuit configuration for realizing the latter becomes complicated.

An example of a conventional method of changing the display position will be described with reference to FIG. FIG. 5A is a front view of a screen when a 4: 3 video signal is displayed on a display unit having a 16: 9 screen. As shown in the figure, non-reflective areas 52 and 53 are formed at the left and right ends of the screen 51. The non-projection area is an area where no video signal is displayed, and the screen remains black.

On the other hand, in the projection area 54, a proper image signal is displayed, and the contrast with the non-projection areas 52 and 53 is large. 5 (b) to (i) show the non-projection area 52 and the projection area 54 in a strip graph form in order to facilitate understanding of the non-projection area 52 and the projection area 54. The boundary with the region 54 is indicated by the line 55.

By changing the display position of the image, the boundary line 55 between the non-projection area 52 and the projection area 54 is changed to that shown in FIG.
The normal position shown in (c) is shifted to the left as shown in FIG. 5 (d), then returned to the normal position again as shown in FIG. 5 (e), and then shown in FIG. 5 (f). As shown in FIG. 5 (g), it returns to the normal position again, and this is repeated thereafter.

As described above, conventionally, there has been a device for displaying the display so that the display position is shifted to the left and right with the regular display position sandwiched therebetween. However, in this case, the display position is changed only in three patterns. As shown in FIG. 6A, an intermediate area 61 having a medium contrast is generated between the left display position and the right display position, and a large area is formed at the boundary between the non-projection area 62 and the projection area 63. Since there is no contrast difference, strong image sticking does not occur, but the border becomes linear,
As shown in FIG. 6 (b), the seizure strength becomes stepwise,
It had a problem that a moderate degree of image sticking still occurred.

As described above, since the conventional measures for preventing the burning depend on the operation of the user, there is no effect if the user does not perform the operation as expected, and the display position is temporarily adjusted at an appropriate timing. However, even if the display position is changed, the display position is not moved finely, so a sufficient anti-seizure effect cannot be expected.In addition, in the display device in which independent measures are taken regardless of the user's operation, There was a problem that the target means became complicated.

[0014]

It is desired to develop an apparatus capable of reliably and easily preventing the screen burn-in phenomenon. According to the present invention, the display position of the video signal is configured so that its moving range dynamically changes with time.

[0015]

An image display device of the present invention comprises a video signal input terminal to which a video signal is supplied, and a clocking means for measuring time based on a synchronizing signal of the video signal.
The phase adjustment means for switching the phase of the synchronizing signal of the video signal supplied to the input terminal to the advancing direction and the backward direction on the basis of the measurement result of the time measuring means, and the video signal output from the phase adjusting means. Display means for displaying based on the adjusted synchronization signal.

According to the present invention, the phase of the synchronizing signal of the video signal to be displayed is adjusted so as to be advanced or backward according to the measurement result of the means for measuring the time based on the synchronizing signal. Therefore, it is possible to reliably prevent the display device from being burned with a simple configuration.

Further, the image display method of the present invention comprises the steps of inputting a video signal, measuring time based on the synchronizing signal of the input video signal to obtain time information, and based on the time information. The step of changing the phase of the sync signal of the input video signal in the advancing direction and the backward direction and outputting the same, and displaying the video signal in which the phase of the sync signal is adjusted. To do.

Also in the present invention, the phase of the synchronizing signal of the video signal to be displayed is adjusted so as to be advanced and backward according to the measurement result of the means for measuring the time based on the synchronizing signal. Therefore, it is possible to reliably prevent the display device from burning with a simple configuration.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image display device of the present invention. A video signal is supplied from the input terminal 11. The video signal is, for example, Y (luminance component), P
b (color difference component) and Pr (color difference component),
It is supplied to the display synchronization generation unit 12 and is also guided to the display position adjustment unit 13. The display synchronization generation unit 12 extracts a synchronization signal including a vertical synchronization signal and a horizontal synchronization signal from the video signal and supplies the synchronization signal to the display position adjustment unit 13 and the time measurement unit 14. The time measuring unit 14 measures time based on the synchronization signal and outputs a phase adjustment control signal to the display phase adjusting unit 13. The display phase adjustment unit 13 adjusts the phase of the synchronization signal from the display synchronization generation unit 12 based on the control signal from the time measurement unit 14, and forms the phase-adjusted synchronization signal as the synchronization signal of the input video signal. From the display phase adjustment unit 13,
The video signal with the phase of the synchronization signal adjusted is the drive unit 15
And the video signal is displayed on the display unit 16 via the drive unit 15.

The time measuring unit 14 can be composed of, for example, a counter that counts the vertical synchronizing signal and a ROM (read-only memory) that uses the count value of the counter as address information, and adjusts the phase of the synchronizing signal in the ROM. The data for doing is stored in advance.

The display phase adjusting section 13 includes, for example, a shaping section for removing a sync signal from an input video signal, and a display sync generating section 1.
The phase adjustment unit that adjusts the phase of the synchronization signal from No. 2 based on the control data from the time measurement unit 14 and the combination unit that combines the phase-adjusted synchronization signal and the input video signal from which the synchronization signal has been removed. Can be configured.

The operation of the image display device configured as described above will be described in detail with reference to FIGS. 2 is shown in FIG.
5 is a waveform diagram illustrating the principle of operation of the display phase adjustment unit 13 of the block diagram shown in FIG. FIG. 2A shows the luminance component of the input video signal. FIG. 2B is a waveform obtained by deleting the synchronization component from FIG. FIG. 2C is a waveform diagram for explaining a process of adjusting the phase of the display synchronization signal supplied from the display synchronization generation unit 12 of FIG. 1 by the control signal from the time measurement unit 14. As shown in FIG. 2C, the display synchronization signal is adjusted at (t) between the phase advanced state and the phase retarded state indicated by the dotted line, centering on the state where the phase adjustment is not indicated by the solid line. It 2 (d) is shown in FIG. 2 (b).
3 is a waveform diagram of a state in which the video signal of FIG. 2 and the phase-adjusted display synchronization signal of FIG. 2C are combined and generated as a video signal for display.

When the phase of the display synchronization signal is advanced, the display position shifts to the left on the screen, and when the phase is retreated,
The display position shifts to the right. According to the present invention, on the basis of the principle described above, the display synchronization signal is counted to obtain time information, the display position is changed according to time, and the shift amount of the display position is changed with time. It has a feature.

The operation will be described in detail with reference to FIG. FIG. 3 (a) shows the sync signal so that the display position is alternately changed to the left and right with time with the phase of the sync signal not being adjusted and the amount of the change is changed with time. It is shown schematically to adjust the phase.

That is, the state where the phase of the synchronizing signal is not adjusted is ± 0, and a predetermined time (for example, about 10 minutes)
After the lapse of time, the phase of the synchronization signal is adjusted so that the display position slightly moves to the + side from there. When the display in that state elapses for a predetermined time (for example, about 10 minutes), the synchronization signal is moved so that the display position moves to the − side by a predetermined amount (a value larger in absolute value than the previous + side movement amount). Adjust the phase. When the display is performed for a predetermined time in that state, the phase of the synchronizing signal is adjusted again so that the display position moves to the + side by a predetermined amount (a value larger in absolute value than the previous-side movement amount). The operation is repeated until the movement amount reaches the predetermined value (+ to 1
When 0) and 10) are reached on the minus side, the movement amount is gradually reduced this time, and the phase adjustment of the synchronization signal is not performed ±
Reset to 0. Then, the movement amount of the display position is gradually increased again, and when it reaches the maximum value, the movement amount is decreased and returns to ± 0. This is repeated thereafter.

As a result, the display position shifts left and right around the display position where the phase of the synchronizing signal is not adjusted,
Since the amount of change gradually changes, the display position becomes a form integrated by time, and the seizure strength also becomes a curve as shown in FIG. 3B, and seizure can be sufficiently suppressed. it can. Furthermore, as for the display position, as a result, the most positions where the phase of the synchronizing signal is not adjusted are displayed, so that the user does not feel a sense of discomfort even when looking at the screen.

FIG. 4 is a flow chart for explaining the operation of the apparatus shown in FIG. First, a routine for measuring the time is set, which is started in the start step 4a,
In step 4b, the time measurement based on the synchronization signal is executed,
It is done continuously.

The display position shifting process is started in step 4c.
In step 4d, a process of adjusting the position of the synchronization signal is performed so that the display position is displaced by a predetermined amount in the + (plus) direction after a predetermined time has elapsed from the initial display state. The time information used in the display position shift process uses the measurement time of step 4b.

Next, in step 4e, after a lapse of a predetermined time, the phase of the synchronizing signal is adjusted so that the display position shifts in the negative (-) direction by a predetermined amount. Then, in step 4f,
After the lapse of a predetermined time, the phase of the synchronization signal is adjusted so that the display position further shifts in the + direction by a predetermined amount.
In g, the phase of the synchronization signal is adjusted so that the display position further shifts in the − direction by a predetermined amount after a predetermined time elapses.

Next, in step 4h, it is judged whether or not the amount of displacement of the display position has become maximum, and if the maximum amount of displacement has not been reached, the process returns to step 4f. When it is determined in step 4h that the displacement amount is the maximum, step 4i
After a lapse of a predetermined time, the phase adjustment of the synchronizing signal is executed so that the display position becomes the maximum displacement amount minus the predetermined amount in the + direction.

Next, at step 4j, after a predetermined time has passed,
The phase adjustment of the synchronization signal is executed so that the display position becomes the minus displacement in the negative direction by a predetermined amount. Next, in step 4k, after a lapse of a predetermined time, the phase of the synchronizing signal is adjusted so that the display position is further reduced by a predetermined amount in the + direction. The phase of the synchronization signal is adjusted so that the phase is further reduced by a predetermined amount in the direction.

Next, in step 4m, it is determined whether the display position has returned to the initial display position. If it is not the initial position, the process returns to step 4k, and if it is determined that it is the initial display position, the step Return to 4d.

As described above, according to the image display device of the present invention, when the display position of the video signal on the screen is changed by time, the image signal is changed in the opposite direction alternately with time centering on the position which is not changed. Moreover, since the amount of the change is increased / decreased in a predetermined cycle, the display position is integrated with time, and the burning phenomenon can be made difficult to occur. In addition, since a large number of images are displayed in a state closer to the center around the state where the display position is not changed, visual discomfort can be suppressed.

[0034]

As described above, according to the image display device of the present invention, when the display position of the video signal is changed,
Since the amount of shift periodically increases and decreases with time, the phenomenon of image sticking can be suppressed, and further, the display can be made visually without a feeling of strangeness.

[Brief description of drawings]

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

FIG. 2 is a waveform chart for explaining the operation of the device shown in FIG.

FIG. 3 is a diagram for explaining the operation of the apparatus shown in FIG.

4 is a flowchart for explaining the operation of the apparatus shown in FIG.

FIG. 5 is a diagram for explaining the operation of a conventional display device.

FIG. 6 is a diagram for explaining the operation of a conventional display device.

[Explanation of symbols]

11 ... Input end 12 ... Display synchronization generator 13 ... Display phase adjustment unit 14 ... Time measurement unit 15 ... Drive section 16 ... Display

Claims (6)

[Claims] 1. A video signal input terminal to which a video signal is supplied, a time measuring means for measuring time based on a synchronizing signal of the video signal, and a video supplied to the input terminal based on a measurement result of the time measuring means. Phase adjustment means for switching the phase of the synchronization signal of the signal to the advancing direction and the backward direction in units of a predetermined time, and a display means for displaying the video signal output from the phase adjustment means based on the adjusted synchronization signal. An image display device characterized by being provided. 2. The image display device according to claim 1, wherein the phase adjusting unit further changes the amount of phase shift of the synchronization signal based on the measurement result of the clocking unit. 3. The phase adjusting means is for altering the phase of the synchronizing signal alternately in the advancing direction and the retreating direction based on the measurement result of the timing means. The image display device according to. 4. The image display device according to claim 1, wherein the phase adjusting unit changes the phase of the synchronization signal in frame units. 5. The image display device according to claim 1, wherein the sync signal is either a horizontal sync signal or a vertical sync signal or both sync signals. 6. A step of inputting a video signal, a step of measuring time based on a synchronizing signal of the input video signal to obtain time information, and a step of measuring the time of the input video signal based on the time information. An image display method comprising: a step of changing a phase of a synchronization signal in an advancing direction and a backward direction and outputting the same; and a step of displaying a video signal in which the phase of the synchronization signal is adjusted.