JP2003044019A - Display control device and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the influence of noise in display elements according to the noise level and the quantity in a video signal, and to improve the delay in the display response speed of the display elements at the time of a sudden change in gradation of brightness. SOLUTION: This display control device which controls matrix type display elements differing in the display response speed corresponding to the gradations of brightness based on video signals, is provided with a response speed improving means 50 for correcting the video signals to improve the display response speed of the display elements, and a noise detecting means 60 for detecting noise from the video signals. The display control device outputs either the video signals before correction or the corrected video signals obtained by the response speed improving means 50 based on the noise level detected by the noise detecting means 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma-driven liquid crystal display (PALC) and a liquid crystal television (LCDT) which supply a video signal for each frame to display an image.
V), a liquid crystal projector (LCDPJ) and the like, and a display control device and an image display device suitable for the application. Specifically, in the case of controlling the display of a matrix type display element having a different display response speed corresponding to the brightness gradation of the video signal, the brightness gradation of the video signal is corrected based on the noise level, or it is prepared in advance. A display response speed improving means for improving the display response speed of the display element by selecting luminance gradation data relating to the video signal, and improving the display response speed based on the noise level of the video signal detected by the noise detecting means. The corrected image signal including the uncorrected image signal is output from the means so that the influence of noise in the display element can be reduced according to the noise level and the amount of noise in the image signal, and the brightness gradation It is possible to improve the delay of the display response speed when there is a sudden change.

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels, which are characterized by being thinner than cathode ray tubes (CRTs), can be manufactured in larger sizes with improved production yields, and analog terrestrial broadcast programs can be converted to ordinary CRTs. It has started to be received and displayed in the same manner as the equipped TV.

A liquid crystal drive circuit is connected to this type of liquid crystal display panel, a predetermined drive voltage is generated based on the input video data of the luminance gradation level, and this drive voltage is applied to the liquid crystal display panel. Brightness gradation control is performed. In this brightness gradation control, the liquid crystal drive circuit can sufficiently generate a drive voltage to follow the brightness gradation level, and this drive voltage can be applied to the liquid crystal display panel.

[0004]

By the way, according to the conventional liquid crystal display device, there is a case where the liquid crystal cannot sufficiently follow the drive voltage due to the variation of the luminance gradation level of the image data in the response of the transmitted light of the liquid crystal. is there. It is considered that this depends on the recovery time of the twist of the liquid crystal.

For this reason, when fast-moving image data, for example, an image with a sharp change in brightness is input to the liquid crystal drive circuit, the liquid crystal cannot follow the change in brightness, that is, the drive voltage, and the outline is blurred. There is a problem that it becomes an image.

To solve this problem, Japanese Patent Publication No. 2708746 discloses a liquid crystal control circuit. According to this liquid crystal control circuit, the stored gradation data A of the frame immediately preceding the current frame is compared with the input gradation data B of the current frame, and when B> A, the predicted correction gradation data is calculated. Is output, and when A <B, the input gradation data B is output as it is. Therefore, there is a problem that the brightness gradation control largely depends on the prediction accuracy.

Further, a technical document, Japanese Patent Laid-Open No. 2885/1992.
A liquid crystal display device is described in Japanese Patent Publication No. 89. According to this liquid crystal display device, the level fluctuation of each pixel in the time axis direction is detected from the video signal of the field image immediately before the current frame and the input video signal of the current frame, and the high frequency band is detected based on the detected level. By controlling the emphasis filter, the display response speed in the intermediate gradation is increased. Therefore, there is a problem that the luminance gradation control largely depends on the characteristics of the high-frequency emphasis filter.

Further, according to the display control device of the video signal correction system, when the video signal contains noise, the noise is emphasized by passing through the correction circuit, and the noise is conspicuous in the display element. There is a problem that it ends up.

Therefore, the present invention solves the above-mentioned conventional problems, and makes it possible to reduce the influence of noise in the display element according to the noise level and the amount of noise in the video signal, and to reduce the luminance level. An object of the present invention is to provide a display control device and an image display device capable of improving the delay property of the display response speed when the key suddenly changes.

[0010]

The above-mentioned problem is an apparatus for controlling the display of a matrix type display element having a different display response speed corresponding to the luminance gradation of a video signal. Noise detection means for detecting the noise level by calculating the difference between the signal and the video signal of the current frame,
Display for correcting the brightness gradation of the video signal based on the noise level obtained by the noise detecting means, or selecting brightness gradation data relating to the video signal prepared in advance to improve the display response speed of the display element A response speed improving means, wherein the display response speed improving means outputs a corrected video signal including a video signal before correction based on the noise level of the video signal detected by the noise detecting means. Is solved by the display control device.

According to the display control device of the present invention, when the display control of the matrix type display elements having different display response speeds corresponding to the luminance gradation of the video signal is performed, on the other hand, the noise detection means has one The noise level is detected by calculating the difference between the video signal of the previous frame and the video signal of the current frame. On the other hand, the display response speed improving means corrects the luminance gradation of the video signal based on the noise level obtained by the noise detecting means for improving the display response speed of the display element, or converts the video signal into a video signal prepared in advance. The luminance gradation data is selected.

Therefore, based on the noise level of the video signal detected by the noise detecting means, the corrected video signal including the video signal before correction can be output from the display response speed improving means to the display element. Moreover, when the noise level in the video signal is large or the noise amount is large, the video signal before correction can be directly output to the display element without performing the correction process, and the display response speed at the time of a sudden change in luminance gradation The effect of noise can be eliminated by making full use of the delay property of.

Further, when the noise level in the video signal is small or the noise amount is small, the corrected video signal can be output to the display element, and the delay of the display response speed at the time of a sudden change in the brightness gradation can be suppressed. Can be improved.

The image display device according to the present invention has a matrix type display element having a different display response speed corresponding to the luminance gradation of the video signal, and displays an image based on the drive voltage applied for each frame. The display control means includes a video display means for displaying, a display drive means for supplying an applied voltage to the video display means, and a display control means for controlling input / output of the display drive means. Noise detecting means for detecting the noise level by calculating the difference between the video signal and the video signal of the current frame, and correcting the luminance gradation of the video signal based on the noise level obtained by the noise detecting means, or A video signal detected by the noise detecting means, which has a display response speed improving means for selecting the luminance gradation data related to the video signal prepared in advance to improve the display response speed of the display element. It is characterized in that so as to output a corrected video signal including a pre-correction of the video signal from the display response speed improvement means based on the noise level.

According to the image display device of the present invention, the above-described display control device is applied to display control of a matrix type display element having a different display response speed corresponding to the luminance gradation of a video signal. It is a thing.

Therefore, based on the noise level of the video signal detected by the noise detecting means, the corrected video signal including the video signal before correction can be output from the display response speed improving means to the display element. Moreover, when the noise level in the video signal is large or the noise amount is large, the video signal before correction can be directly output to the display element without performing the correction process, and the display response speed at the time of a sudden change in luminance gradation The effect of noise can be eliminated by making full use of the delay property of.

Further, when the noise level in the video signal is small or the noise amount is small, the corrected video signal can be output to the display element, and the delay of the display response speed at the time of a sudden change in the brightness gradation can be suppressed. Can be improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a display control device and an image display device according to the present invention will be described with reference to the drawings. (1) First Embodiment FIG. 1 is a block diagram showing a configuration example of a display control device 100 as a first embodiment according to the present invention. 2A to E
FIG. 3 is a block diagram showing a configuration example of noise detection means 60. In this embodiment, when the display control of the matrix type display elements having different display response speeds corresponding to the luminance gradation of the video signal is performed, the luminance gradation of the video signal is corrected based on the noise level, or in advance. A response speed improving unit that selects the luminance gradation data relating to the prepared video signal to improve the display response speed of the display element is provided, and the response speed is improved based on the noise level of the video signal detected by the noise detecting unit. The means outputs the post-correction video signal including the pre-correction video signal.

The influence of noise in the display element can be reduced according to the noise level and the amount of noise in the video signal, and the delay of the display response speed at the time of a sudden change in the luminance gradation can be improved. It is a thing.

The display control device 100 shown in FIG. 1 is a device for controlling the display of a matrix type display element having a different display response speed corresponding to a luminance gradation based on a video signal SIN input for each frame. The display control device 100 includes a response speed improving means 50, a noise detecting means 60, and a control device 70. The response speed improving means 50 corrects the video signal SIN input for each frame in order to improve the display response speed of the liquid crystal display device or the like. The noise detecting means 60 detects the noise level N from the video signal SIN.
L is detected. Of course, the noise amount may be detected from the video signal SIN.

The noise detecting means 60 includes a control device 70.
Are connected and controlled to output either the pre-correction video signal SIN or the post-correction video signal SOUT obtained by the response speed improving means 50 based on the external control signal CTL and the noise level NL. . Noise detection means 6
For 0, for example, a frame memory 61, a difference detection circuit 62, and a non-linear filter circuit 63 shown in FIG. 2A are used.

The frame memory 61 shown in FIG.
The video signal S of the frame immediately before the current frame shown in B
IN 'is input and this video signal SIN' is stored. In this example, the noise level of the video signal SIN of the current frame shown in FIG. 2C is higher than that of the video signal SIN ′ of the immediately preceding frame. The signal component of the video signal SIN ′ of the frame immediately preceding the current frame is I1 and the noise component is N1. The signal component of the video signal SIN of the current frame is I2 and the noise component is N2.

A difference detection circuit 62 is connected to the frame memory 61, and the video signal SIN ′ of the previous frame stored in the frame memory 61 and the video signal SIN of the current frame are input to the frame memory 61. The difference between the video signals SIN between the frames is calculated to detect the motion components I1-I2 and the noise components N1-N2 between the frames shown in FIG. 2D.

Motion component I1-I2 and noise component N1-
N2 is the difference detection circuit 62 as the inter-frame difference signal SN.
Is output to the non-linear filter circuit 63. The nonlinear filter circuit 63 has the input-output characteristic shown in FIG. 2E. The vertical axis represents the output level (noise component), and the horizontal axis represents the input level (interframe difference signal SN). The non-linear filter circuit 63 removes the motion components I1 and I2 having a large input level from the inter-frame difference signal SN and extracts only the noise component. Then the noise component is integrated,
The noise level NL is output to the control device 70 shown in FIG.

In this control device 70, the response speed improving means 5
0 is a case where the video signal SIN is corrected corresponding to a predetermined correction amount, and the correction amount of the response speed improving means 50 is variably set based on the noise level NL detected by the noise detecting means 60. It The control device 70 outputs the correction control signal Sa to the response speed improving means 50 to variably set the correction amount. This is to improve the delay in the display response speed of the display element corresponding to the brightness gradation.

Next, an operation example of the display control device 100 will be described. FIG. 3 is a flowchart showing an operation example of the display control device 100 according to the first embodiment of the present invention. In this embodiment, on the assumption that the matrix type display elements having different display response speeds corresponding to the brightness gradation are display-controlled based on the video signal SIN,
When the video signal SIN is input to the display control device 100 in step A1 of the flowchart shown in FIG. 3, the response speed improving means 50 corrects the video signal SIN in order to improve the display response speed of the display element in step A2. It

In parallel with this, noise is detected from the video signal SIN by the noise detecting means 60 in step A3. The noise level NL detected here is the control device 70.
Is output to. In the control device 70, in step A4, either the video signal SIN of the current frame (before correction) or the corrected video signal SOUT including the video signal SIN before correction obtained by the response speed improving means 50 is selected based on the noise level NL. Is controlled to output.

Therefore, when the noise level NL in the video signal is small or the noise amount is small, the corrected video signal SOUT is corrected by increasing the difference between the video signals of the current frame and the frame immediately preceding the current frame. Can be output to the display element, and the delay of the display response speed of the display element at the time of a sudden change in luminance gradation can be improved.

When the noise level NL in the video signal is high or the noise amount is high, the video signal SIN before correction is
Can be directly output to the display element, and the effect of noise can be eliminated by fully utilizing the delay characteristic of the display response speed of the display element when the brightness gradation changes suddenly. Instead of outputting the uncorrected video signal SIN to the display element as it is, the corrected video signal SOUT that suppresses the difference between the video signal SIN ′ of the current frame and the preceding frame is output to the display element. In this way, noise may be made less noticeable.

Furthermore, according to the flow chart shown in FIG. 3, the noise detection processing in step A2 and the correction processing in step A3 are executed in parallel. However, as shown in the broken line diagram, step A2 The correction process in step A3 may be executed after the noise detection process in step A3.

(2) Second Embodiment FIG. 4 is a block diagram showing a configuration example of a display control device 200 according to a second embodiment of the present invention. In this embodiment, when the matrix type display elements having different display response speeds corresponding to the luminance gradation are display-controlled based on the video signal SIN, the video signal SIN before correction is based on the noise level NL in the video signal. Alternatively, a selection unit 80 for selecting one of the output candidates of the plurality of video signals SOUT corrected by the response speed improvement unit 50 is provided, and when the noise level NL in the video signal is large or the noise amount is large, the luminance level is increased. It is possible to eliminate the influence of noise by utilizing the delay of the display response speed of the display element at the time of a sudden change in the tone, and, when the noise level NL in the video signal is small or the noise amount is small, the brightness gradation It is possible to improve the delay of the display response speed of the display element at the time of sudden change.

The display control device 200 shown in FIG. 4 is a device for controlling the display of a matrix type display element having different display response speeds corresponding to luminance gradations based on a video signal SIN input for each frame. The display control device 200 includes a response speed improving means 50, a noise detecting means 60, and a selecting means 8.
0 and a control device 70.

The response speed improving means 50 has a selecting means 8
0 is connected, and one of the output candidates of the video signal SIN before correction or the plurality of video signals SOUT after correction including the video signal SIN before correction obtained by the response speed improving means 50 is based on the noise level NL. To be selected. The control device 70 outputs the selection control signal Sc to the selection means 80 to select, for example, the uncorrected video signal SIN.

In the control device 70, for example, the noise detecting means 6
The noise level NL detected by 0 is compared with a preset reference value. The reference value is set by the external control signal CTL. For example, when the noise level NL exceeds the reference value, the video signal SIN before correction is selected, and when the noise level NL is less than the reference value, the video signal SOUT after correction by the display response speed correction circuit is selected. Then, the selection means 80 is controlled. Note that the same names and reference numerals as those in the first embodiment have the same functions, and therefore their explanations are omitted.

As described above, according to the display control device 200 as the second embodiment of the present invention, the matrix type display elements having different display response speeds corresponding to the luminance gradation are generated based on the video signal SIN. Assuming display control,
When the video signal SIN is input to the display control device 70,
On the other hand, the image signal SIN is corrected by the response speed improving means 50 in order to improve the display response speed of the display element.

In parallel with this, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is output to the control device 70. The control device 70 compares the noise level NL detected by the noise detection means 60 with a preset reference value,
When the noise level NL exceeds the reference value, the video signal SIN before correction is selected, and when the noise level NL is less than the reference value, the video signal SOUT after correction by the response speed improving means 50 is selected. It

Therefore, when the noise level NL in the video signal is large or the noise amount is large, the uncorrected video signal SIN can be directly output to the display element in the same manner as in the first embodiment. The effect of noise can be eliminated by making full use of the delay of the display response speed of the display element when the key suddenly changes. Further, when the noise level NL in the video signal is small or the noise amount is small, the corrected video signal SOUT can be output to the display element, and the display response speed of the display element is delayed when the brightness gradation suddenly changes. The sex can be improved.

(3) First Embodiment FIG. 5 is a block diagram showing a structural example of an image display device 201 to which the display control device 101 according to the first embodiment of the present invention is applied. In this embodiment, when the display control of the matrix type display element having the different display response speed corresponding to the luminance gradation of the video signal SIN is performed, the noise detection means 60 for detecting the noise from the video signal SIN is provided. Either the pre-correction video signal SIN or the post-correction video signal SOUT is output based on the noise level NL. Then, the control device 70 variably sets the correction amount based on the noise level NL.

The image display device 201 shown in FIG. 5 displays an image based on the video signal SIN input for each frame, and includes the display control device 101 and the display drive means 11.
And a video display means 12. Display controller 10
Reference numeral 1 is an example of display control means, which controls the input / output of the display drive means 11.

A display drive means 11 is connected to the display control device 101, and an applied voltage is supplied to the image display means 12. For example, when a liquid crystal display panel is used as the image display unit 12, a scan electrode drive IC or a signal electrode drive IC is used as the display drive unit 11 depending on the display format.

The display drive means 11 includes the image display means 1
2 are connected, and an image is displayed based on the drive voltage VOUT applied for each frame. The image display means 12 is an example of a matrix type display element.
A liquid crystal display panel will be used. The video display means 12 is configured to display an image based on the drive voltage applied for each frame. This type of display element has a different display response speed according to the brightness gradation.

The display control device 101 has a first response speed improving means 51, a noise detecting means 60 and a control device 70. The response speed improving means 51 has the first storage means 1 and the correction circuit 3 for correcting the video signal SIN, and is adapted to improve the display response speed of the video display means 12.

The first storage means 1 stores the video signal SIN 'of the frame immediately preceding the current frame. Randomly accessible memory (R
AM) is used. A correction circuit 3 is connected to the storage means 1, and a video signal S input every frame is inputted.
In the case of correcting IN, 1 stored in the storage unit 1
The difference Lε between the luminance gradation of the video signal SIN ′ of the previous frame and the luminance gradation of the video signal SIN of the current frame is calculated,
A correction value corresponding to the difference Lε is calculated and output as the luminance gradation of the video signal SIN of the current frame.

The noise detecting means 60 detects the noise level NL from the video signal SIN. A control device 70 is connected to the correction circuit 3 and the noise detection means 60. In the case where the control device 70 corrects the video signal SIN according to a predetermined correction amount, the noise detection means 60
The correction amount of the correction circuit 3 is variably set based on the noise level NL detected by.

The control device 70 outputs a correction control signal Sa to the correction circuit 3 to variably set the correction amount. This is to improve the delay in the display response speed of the display element corresponding to the brightness gradation. Moreover, the control device 70 outputs either the video signal SIN before correction or the video signal SOUT after correction by the response speed improving means 51 based on the noise level NL. A CPU (Central Processing Unit) is used for the correction circuit 3 and the control device 70.

FIG. 6 is a diagram of luminance gradation levels showing an example of correction processing in the correction circuit 3. The vertical axis shown in FIG. 6 is the luminance gradation level of the video signal SIN input to the correction circuit 3, and the horizontal axis is the time t. L1 is the luminance gradation level of the video signal SIN of the frame preceding the current frame. L2 is the luminance gradation level of the video signal SIN of the current frame.
Lε is the difference between the luminance gradation level L1 of the video signal SIN of the frame preceding the current frame and the luminance gradation level L2 of the video signal SIN of the current frame, and is calculated by the equation (1). Lε = L1-L2 (1) Lri is a correction value for the luminance gradation level L2 of the video signal SIN of the current frame.

Further, L2 'shown in FIG. 6 is the luminance gradation level of the video signal SIN of the corrected current frame, which is calculated by the equation (2). L2 '= L2 + Lri ... (2)

That is, when the luminance gradation level L2 of the video signal SIN of the current frame is lower than the luminance gradation level L1 of the video signal SIN of the frame preceding the current frame,
Since the negative correction value -Lri is applied, the video signal SIN having a lower luminance gradation obtained by subtracting the correction value Lri from the luminance gradation level L2 of the video signal SIN of the current frame is output.

If the luminance gradation level L2 of the video signal SIN of the current frame is higher than the luminance gradation level L1 of the video signal SIN of the previous frame, the positive correction value + Lri is applied. Therefore, the video signal SIN having a higher brightness gradation obtained by adding the correction value + Lri to the brightness gradation level L2 of the video signal SIN of the current frame is output.

In this example, in the correction circuit 3, the difference Lε between the brightness gradation of the video signal SIN ′ of the immediately preceding frame stored in the storage means 1 and the brightness gradation of the video signal SIN of the current frame is substantially zero. In this case, the video signal SIN of the current frame is output as it is. Regarding the specific brightness gradation range of the video signal SIN, the brightness gradation of the video signal SIN of the current frame is lower than the brightness gradation of the video signal SIN ′ of the previous frame stored in the storage unit 1. In this case, the video signal SIN having a lower luminance gradation obtained by subtracting the correction value from the luminance gradation of the video signal SIN of the current frame is output.

If the luminance gradation of the video signal SIN of the current frame is higher than the luminance gradation of the video signal SIN 'of the immediately preceding frame stored in the storage means 1, the video signal of the current frame A video signal SIN having a higher luminance gradation obtained by adding a correction value to the luminance gradation of SIN is output.

As described above, according to the image display device 201 as the first embodiment of the present invention, the image display means 1 having a different display response speed corresponding to the luminance gradation of the image signal SIN.
If the video signal SIN is input to the display control device 101 on the premise that the display control of the display device 2 is performed, the video display means 1
The video signal SIN is corrected by the correction circuit 3 in order to improve the display response speed of No. 2.

In parallel with this, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is output to the control device 70. The control device 70 outputs either the video signal SIN before correction or the video signal SOUT after correction obtained by the correction circuit 3 based on the noise level NL.

Therefore, when the noise level NL in the video signal is large or the noise amount is large, the video signal S before correction S
IN can be output to the display element as it is, and the influence of noise can be eliminated by making full use of the delay of the display response speed of the display element when the brightness gradation suddenly changes.

If the noise level NL in the video signal is small or the noise amount is small, the corrected video signal S
OUT can be output to the display element, and the delay of the display response speed of the display element at the time of a sudden change in luminance gradation can be improved.

In this example, the case where the correction value Lri is calculated by the control device 70 has been described, but the present invention is not limited to this. The correction value Lri calculated in advance may be stored in the ROM or the like, and may be read from the ROM and used for correction.

(4) Second Embodiment FIG. 7 is a block diagram showing a configuration example of an image display device 202 to which the display control device 102 according to the second embodiment of the present invention is applied. In this embodiment, the correction circuit 3 shown in FIG.
The second storage means 2 is connected between the control device 70 and the
The correction value Lri calculated in advance is stored, and the correction value Lri is read from the storage means 2 and used at the time of correction. Of course, the noise detection means 60 and the control device 70 are provided, and the influence of noise is reduced by controlling the correction value Lri of the correction circuit 3 or the presence or absence of operation according to the degree of noise.

The image display device 202 shown in FIG. 7 displays an image based on the video signal SIN input for each frame, and includes the display control device 102 and the display drive means 11.
And a video display means 12. Display controller 10
Reference numeral 2 is an example of display control means, which controls the input / output of the display drive means 11.

The display control device 102 has a second response speed improving means 52, a noise detecting means 60 and a control device 70. The response speed improving means 52 has a first storage means 1, a second storage means 2 and a correction circuit 3 for correcting the video signal SIN so as to improve the display response speed of the video display means 12. Done.

In this display control device 102, the second storage means 2 is connected to the correction circuit 3, and the correction value Lri corresponding to this difference Lε is stored. The control device 70 controls the reading of the storage means 2 based on the read control signal OE. A read-only memory (ROM) is used as the storage unit 2. The optimum value of the correction value Lri is obtained in advance according to the type of the image display means 12,
The correction value Lri is converted into a reference table and stored in the ROM or the like.

In this example as well, in the correction circuit 3, the difference L between the luminance gradation of the video signal SIN 'of the immediately preceding frame stored in the storage means 1 and the luminance gradation of the video signal SIN of the current frame.
When ε is almost zero, the video signal SIN of the current frame is output as it is.

Regarding the specific luminance gradation range of the video signal SIN, as compared with the luminance gradation of the video signal SIN ′ of the previous frame stored in the storage means 1, the luminance level of the video signal SIN of the current frame. If the tone is low, the video signal SIN of a lower luminance gradation obtained by subtracting the correction value from the luminance gradation of the video signal SIN of the current frame is output.

If the luminance gradation of the video signal SIN 'of the current frame is higher than the luminance gradation of the video signal SIN' of the previous frame stored in the storage means 1, the video signal of the current frame is A video signal SIN having a higher luminance gradation obtained by adding a correction value to the luminance gradation of SIN is output.

The display drive means 11 is connected to the correction circuit 3 so that the drive voltage VOUT is generated based on the corrected video signal SOUT and the drive voltage VOUT is supplied to the video display means 12. It Since the same names and reference numerals as those of the first embodiment have the same functions,
The description is omitted.

FIG. 8 is an image diagram showing an example of the contents of the reference table in the storage means (ROM) 2. This ROM has 1
Luminance gradation level L1 of the video signal SIN ′ of the previous frame
When the difference Lε between the video signal SIN of the current frame and the luminance gradation level L2 of the current frame is substantially zero, “0” is described as the correction value in order to output the video signal SIN of the current frame as it is.

Video signal S of the frame before the current frame
When the brightness gradation level L2 of the video signal SIN of the current frame is lower than the brightness gradation level L1 of IN, that is,
When the calculation result of the equation (1) is Lεi> 0, the negative correction values are -Lr1, -Lr2, -Lr3, -Lri,
...- Lrn is prepared. On the contrary, the brightness gradation level L1 of the video signal SIN of the current frame is compared with the brightness gradation level L1 of the video signal SIN of the frame preceding the current frame.
When 2 is high, that is, the calculation result of the equation (1) is Lεi.
When <0, + Lr1, + Lr as positive correction values
2, + Lr3, + Lri, ... + Lrn are prepared (see FIG. 8).

When the correction of suppressing the difference between the video signal SIN ′ of the current frame and the frame immediately before the current frame is performed instead of outputting the video signal SIN before correction to the display element as it is, the correction content ( It is advisable to use a correction value whose sign is opposite to that of the above-mentioned correction value although the absolute value of the data is different. When the video signal SOUT corrected using such a correction value is output to the display element, noise can be made even less noticeable.

Next, an operation example of the image display device 202 will be described. FIG. 9 is a flowchart showing an operation example of the image display device 202. In this embodiment, it is premised that the image display means 12 having a different display response speed depending on the luminance gradation is subjected to display control based on the image signal SIN input for each frame.

In this image display device 202, the correction value ± Lri as shown in FIG. 8 is stored in the storage means 2 shown in FIG. In this example, when the difference Lε between the luminance gradation level L1 of the video signal SIN of the frame preceding the current frame and the luminance gradation level L2 of the video signal SIN of the current frame is substantially zero, the video signal SIN of the current frame Is output as it is, and the video signal S of the current frame is compared with the luminance gradation level L1 of the video signal SIN of the previous frame of the current frame.
When the IN brightness gradation level L2 is low or high, it is assumed that the correction is performed with the correction value ± Lri.

With this as a correction condition, when the video signal SIN is input to the display control device 102 in step B1 of the flow chart shown in FIG. 9, the video signal SIN is stored in the storage means 1.
And to the correction circuit 3. In steps B2 to B4, the response speed improving means 52 corrects the image signal SIN in order to improve the display response speed of the image display means 12.

In this example, the process shifts to step B2, and the correction circuit 3 causes the difference Lε between the luminance gradation level L1 of the video signal SIN of the frame preceding the current frame and the luminance gradation level L2 of the video signal SIN of the current frame. Is calculated by the equation (1). After that, the process proceeds to step B3, and the correction value Lri corresponding to the difference Lε is read from the storage unit 2 to the correction circuit 3. Then, proceeding to step B4, the correction circuit 3 uses the correction value Lri to calculate the luminance gradation level L2 ′ of the video signal SIN of the current frame by the equation (2).

In parallel with this, in step B5, the noise detecting means 60 detects noise from the video signal SIN. The noise level NL detected here is the control device 70.
Is output to. In step B6, the control device 70 compares the noise level NL detected by the noise detection means 60 with a preset reference value. When the noise level NL exceeds the reference value, the process proceeds to step B7 and the uncorrected video signal SIN is output as it is. If the noise level NL is less than the reference value, the process proceeds to step B8, and the video signal SOU after correction by the response speed improving means 52 is performed.
It is designed to output T.

As a result, when the noise level NL exceeds the reference value, the drive voltage VOUT generated based on the video signal SIN before correction in step B9 is used as the video display means 12
To be supplied to. Therefore, in step B10, the image display means 12 displays an image based on the drive voltage VOUT applied for each frame. At this time, the influence of noise can be eliminated by fully utilizing the delay property of the display response speed of the display element when the brightness gradation changes suddenly.

If the noise level NL does not exceed the reference value, the drive voltage VOUT generated based on the corrected video signal SOUT is supplied to the video display means 12 in step B9. Therefore, in step B10, the video display means 12 displays the video display means 1 based on the luminance gradation level L2 ′ of the video signal SIN of the corrected current frame.
2 is driven. In step B11, the power-off information and the like are detected, and the image display processing is ended. If the power-off information or the like is not detected, the process returns to step B1 and the above-mentioned image display processing is continued.

Thus, the noise level N in the video signal is
When L is small or the amount of noise is small, it is possible to improve the delay property of the display response speed of the display element when the brightness gradation changes suddenly. Moreover, in this embodiment, the luminance gradation level L1i of the video signal SIN ′ of the frame immediately before the current frame is used.
If the brightness gradation level L2i of the video signal SIN of the current frame is lower than that of the current frame, the video signal SOUT of a lower brightness gradation is obtained by subtracting the correction value Lri from the brightness gradation level L2i of the video signal SIN of the frame. Can be output.

The video signal SIN 'of the immediately preceding frame
When the luminance gradation level L2i of the video signal SIN of the current frame is higher than the luminance gradation level L1i of the current frame, a higher luminance level obtained by adding the correction value Lri to the luminance gradation level L2i of the video signal SIN of the frame. A tonal image signal SOUT can be output.

As a result, even when a liquid crystal display panel is used as the image display means 12, it is possible to sufficiently cope with the fast moving image signal SIN. Further, even when an image with a sharp change in brightness is input, it is possible to prevent the change in brightness, that is, a phenomenon in which the liquid crystal cannot follow the applied voltage and the outline of the image is blurred (sharpness improvement function).

(5) Third Embodiment FIG. 10 is a block diagram showing a configuration example of an image display device 203 to which the display control device 103 according to the third embodiment of the present invention is applied. In this embodiment, the video signal SIN is divided into upper bits and lower bits, and only the upper bits are corrected to reduce the memory capacity of the first storage means 1 as compared with the second embodiment. is there. Of course, the noise detection means 60 and the control device 70 are provided, and the influence of noise is reduced by controlling the correction value Lri of the correction circuit 3 or the presence or absence of operation according to the degree of noise. Note that the same reference numerals and names as those of the first and second embodiments have the same functions, and therefore their explanations are omitted.

The image display device 203 shown in FIG. 10 includes a display control device 103, a display drive means 11 and an image display means 12.
have. The display control device 103 includes the display driving means 11
The third response speed improving means 53, the noise detecting means 60, and the control device 70 are provided.

The response speed improving means 53 has a first storage means 4, a correction circuit 6 and an adding means 7 in order to correct the video signal SIN inputted for each frame. The storage means 4 stores the video signal SIN of the upper bits of the frame preceding the current frame. A RAM having a smaller memory capacity than that of the first embodiment is used as the storage means 4.

A correction circuit 6 is connected to the storage means 4, and the luminance gradation level L1 of the video signal SIN of the upper bit of the immediately preceding frame read from the storage means 4 and the upper bit of the current frame are compared. The difference between the luminance gradation level L2 of the video signal SIN is calculated, and the correction value L corresponding to the difference is calculated.
ri is calculated and output as the luminance gradation level L2 of the video signal SIN of the upper bit of the current frame. This is to improve the display response speed associated with the change in the gradation level of the video signal SIN for each frame in the video display means 12. A CPU (Central Processing Unit) is used for the correction circuit 6.

A correction control signal Sa is input to the correction circuit 6 from the control device 70, and the correction amount is variably set. This is to improve the delay in the display response speed of the display element corresponding to the brightness gradation. In the correction circuit 6, the difference between the luminance gradation level L1 of the video signal SIN of the upper bit of the previous frame stored in the storage means 4 and the luminance gradation level L2 of the video signal SIN of the upper bit of the current frame is calculated. When it is almost zero, the video signal SIN of the upper bit of the current frame is output as it is.

Regarding the specific brightness gradation level range of the video signal SIN, the higher order of the current frame is compared with the brightness gradation level L1 of the video signal SIN of the higher order bit of the previous frame stored in the storage means 4. If the luminance gradation level L2 of the bit video signal SIN is low, the correction value Lr is calculated from the luminance gradation level L2 of the higher-bit video signal SIN of the current frame.
The higher-order video signal SIN having a lower luminance gradation obtained by subtracting i is output.

Further, the luminance gradation level L of the video signal SIN of the higher-order bit of the frame immediately before stored in the storage means 4
Video signal SIN of the upper bit of the current frame compared to 1.
If the luminance gradation level L2 is high, the higher-bit video signal SOUT having a higher luminance gradation level obtained by adding the correction value Lri to the luminance gradation level L2 of the higher-bit video signal SIN of the current frame is output.

In this display control device 103, the adding means 7 is connected to the correction circuit 6, and the video signal SIN of the upper bits of the current frame after the correction calculation is added to the video signal SIN of the lower bits of the current frame before the correction calculation. The signal SIN is added and output. An adder is used as the adding means 7. The video signal SOUT of the current frame after addition is the display driving means 1
It is output to 1. The display drive means 11 generates a drive voltage VOUT based on the video signal SOUT of the corrected luminance gradation level L2i ', and the drive voltage VOUT is generated by the video display means 12.
To be supplied to. In the video display means 12, 1
An image is displayed based on the drive voltage VOUT applied for each frame.

Next, an operation example of the image display device 203 according to the third embodiment will be described. In this example,
It is assumed that the image display means 12 having a different display response speed corresponding to the luminance gradation is display-controlled based on the image signal SIN. With this as a correction condition, the display control device 10
When the video signal SIN is input to 3, the correction circuit 6 corrects the video signal SIN in order to improve the display response speed of the video display unit 12.

In parallel with this, the noise detection means 60 detects noise from the video signal SIN. The noise level NL detected here is output to the control device 70. The control device 70 outputs either the uncorrected video signal SIN or the corrected video signal SOUT obtained by the correction circuit 6 based on the noise level NL.

The correction circuit 6 compares the luminance gradation level L1 of the video signal SIN of the upper bit of the frame immediately before the current frame with the video signal S of the higher bit of the current frame.
When the brightness gradation level L2 of IN is low, the higher-order bit video signal SOUT of a lower brightness gradation obtained by subtracting the correction value Lri from the brightness gradation level L2 of the higher-order bit video signal SIN of the frame is output. You can

If the luminance gradation level L2 of the upper-bit video signal SIN of the current frame is higher than the luminance gradation level L1 of the upper-bit video signal SIN of the immediately preceding frame, Upper bit video signal SIN
It is possible to output the higher-order video signal SOUT having a higher luminance gradation by adding the correction value Lri to the luminance gradation level L2.

Therefore, when the noise level NL in the video signal is large or the noise amount is large, the video signal S before correction S
IN can be output to the display element as it is, and the influence of noise can be eliminated by making full use of the delay of the display response speed of the display element when the brightness gradation suddenly changes.

If the noise level NL in the video signal is small or the noise amount is small, the corrected video signal S
OUT can be output to the display element, and the delay of the display response speed of the display element at the time of a sudden change in luminance gradation can be improved.

As a result, even when a liquid crystal display panel is used as the image display means 12, it is possible to sufficiently cope with the fast moving image signal SIN. Moreover, even when an image with a sharp change in brightness is input, the change in brightness, that is, a phenomenon in which the liquid crystal cannot follow the applied voltage and the outline of the image is blurred can be prevented.

(6) Fourth Embodiment FIG. 11 is a block diagram showing an example of the arrangement of an image display device 204 to which the display control device 104 according to the fourth embodiment of the present invention is applied. In this embodiment, the second storage means 5 is connected between the correction circuit 6 and the control device 70, and of course, the noise detection means 60 and the control device 70 are provided, and the correction circuit 6 is corrected depending on the degree of noise. By controlling the value Lri or the presence or absence of the operation, the influence of noise is reduced. The same reference numerals and names as those of the third embodiment have the same functions, so that the description thereof will be omitted.

The image display device 204 shown in FIG. 11 includes a display control device 104, a display drive means 11 and an image display means 12.
have. The display control device 104 is the display driving means 11
It controls the input / output of the control signal and has a fourth response speed improving means 54, a noise detecting means 60 and a control device 70.

The response speed improving means 54 has a first storage means 4, a second storage means 5, a correction circuit 6 and an addition means 7 in order to correct the video signal SIN input for each frame. There is. The storage means 4 stores the video signal SIN of the upper bits of the frame preceding the current frame. A RAM having a smaller memory capacity than that of the first embodiment is used as the storage means 4. In this example as well, the control device 70 controls the reading of the storage means 5 based on the read control signal OE.

In the display control device 104, the storage means 5 is connected to the correction circuit 6, and the storage means 5 stores the luminance gradation level of the video signal SIN of the higher-order bit of the previous frame stored in the storage means 4. The correction value Lri corresponding to the difference Lε between L1 and the luminance gradation level L2 of the video signal SIN of the upper bit of the current frame is stored. The storage means 5 has a memory capacity R smaller than that of the first embodiment.
OM is used. An optimum value of the correction value Lri is obtained in advance according to the type of the image display means 12, and the correction value Lri is
Is converted into a reference table and stored in the storage means 5 such as a ROM.

Next, an operation example of the image display device 204 as the fourth embodiment according to the present invention will be described. In this embodiment, it is premised that the image display means 12 having a different display response speed according to the luminance gradation is subjected to display control based on the image signal SIN of the upper bit input for each frame.

When the video signal SIN is input to the display control device 104 with this as a correction condition, the high-order bit video signal SIN is input to the storage means 4 and the correction circuit 6.
The video signal SIN of the lower bits is input to the adding means 7. In the display control device 104, the image signal SIN is corrected by the response speed improving means 54 in order to improve the display response speed of the image display means 12.

At the same time, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is output to the control device 70. The control device 70 outputs either the uncorrected video signal SIN or the corrected video signal SOUT obtained by the correction circuit 6 based on the noise level NL.

The control device 70 compares the noise level NL with a preset reference value. When the noise level NL exceeds the reference value, the correction circuit 6 outputs the uncorrected upper-bit video signal SIN to the adding means 7. In the adding means 7, the high-order bit video signal SIN before correction
And the video signal SIN of the lower bits are added,
The video signal SIN before correction can be output as it is.

As a result, the drive voltage VOUT generated on the basis of the video signal SIN before correction is supplied to the video display means 12. Therefore, the image display means 12 displays an image based on the drive voltage VOUT applied for each frame. At this time, the influence of noise can be eliminated by fully utilizing the delay property of the display response speed of the display element when the brightness gradation changes suddenly.

Further, when the noise level NL is less than the reference value, the image signal SOUT corrected by the response speed improving means 54 is output. At this time, the difference Lε between the luminance gradation level L1 of the video signal SIN of the upper bit of the immediately preceding frame and the luminance gradation level L2 of the video signal SIN of the upper bit of the current frame is transferred from the storage means 5 to the correction circuit 6. The correction value Lri corresponding to is read.

In the correction circuit 6, the video signal S of the upper bit of the current frame is compared with the luminance gradation level L1 of the video signal SIN of the upper bit of the frame immediately before the current frame.
When the brightness gradation level L2 of IN is low, the higher-order bit video signal SOUT of a lower brightness gradation obtained by subtracting the correction value Lri from the brightness gradation level L2 of the higher-order bit video signal SIN of the frame is output. You can

If the luminance gradation level L2 of the upper-bit video signal SIN of the current frame is higher than the luminance gradation level L1 of the upper-bit video signal SIN of the immediately preceding frame, Upper bit video signal SIN
It is possible to output the higher-order video signal SOUT having a higher luminance gradation by adding the correction value Lri to the luminance gradation level L2.

Therefore, in the video display means 12, the video display means 12 is driven based on the luminance gradation level L2 'of the video signal SIN of the corrected current frame. in this way,
When the noise level NL in the video signal is small or the amount of noise is small, it is possible to improve the delay property of the display response speed of the display element when the luminance gradation changes suddenly.

As a result, even when a liquid crystal display panel is used as the image display means 12, it is possible to sufficiently deal with the fast moving image signal SIN. Further, even when an image with a sharp change in brightness is input, it is possible to prevent the change in brightness, that is, a phenomenon in which the liquid crystal cannot follow the applied voltage and the outline of the image is blurred (sharpness improvement function).

(7) Fifth Embodiment FIG. 12 is a block diagram showing a structural example of an image display device 205 to which the display control device 105 according to the fifth embodiment of the present invention is applied. In this embodiment, when the display control of the video display means 12 having different display response speed according to the brightness gradation level is controlled based on the video signal SIN input for each frame, in the first to fourth embodiments. The described correction circuit 3,
Instead of 6, etc., a read-only storage means 8 such as a correction value lookup table is provided.

In this example, the luminance gradation level after correction is made by using the luminance gradation level L1 of the video signal SIN 'of the frame immediately preceding the current frame and the luminance gradation level L2 of the video signal SIN of the current frame as addresses. By reading the tonal image signal SOUT, the burden on the arithmetic and control system can be further reduced even when an image with a sharp change in luminance is input.

Moreover, the noise detecting means 60 and the control device 7
0 and a selection means 80 are provided to control the reading of the storage means 8 based on the noise level NL in the video signal to select either the video signal SIN before correction or the video signal SOUT after display response speed correction. It is something that is done. Note that the same reference numerals and names as those of the first embodiment have the same functions, and therefore their explanations are omitted.

The image display device 205 shown in FIG. 12 is a device for controlling the display of the image display means 12 having a different display response speed according to the luminance gradation of the image signal SIN based on the image signal SIN input for each frame. is there. Image display device 205
Has a display control device 105, a display drive means 11 and an image display means 12.

The display control device 105 includes the display driving means 1
In order to control the input / output of 1, the fifth response speed improving means 55, the noise detecting means 60, the control device 70 and the selecting means 80 are provided. The response speed improving means 55 is composed of the first storing means 1 and the second storing means 8, and the storing means 1 stores 1 of the current frame in the same manner as in the first embodiment.
The video signal SIN 'of the previous frame is stored.

Further, the storage means 1 is connected to the storage means 8 and stores the corrected video signal (data) of the optimum luminance gradation level obtained by the correction calculation in advance. A ROM is used as the storage means 8. The video signal SOUT having the corrected brightness gradation is read by using the brightness gradation level L1 of the video signal SIN ′ of the frame immediately preceding the current frame and the brightness gradation level L2 of the video signal SIN of the current frame as addresses. This is because.

The response speed improving means 55 has a selecting means 8
0 is connected, and either the uncorrected video signal SIN or the corrected video signal SOUT obtained by the storage means 8 is selected. In the control device 70, for example, the noise level NL detected by the noise detecting means 60 is compared with a preset reference value. The reference value is set by the external control signal CTL.

For example, when the noise level NL exceeds the reference value, the control device 70 selects the video signal SIN before the correction, and when the noise level NL does not reach the reference value, the response speed improving means 55 performs the correction. The selecting means 80 is controlled so as to select the image signal SOUT. The control device 70 outputs the selection control signal Sc to the selection means 80 to select the video signal SIN before correction. This selection means 8
A display drive means 11 is connected to 0, and an applied voltage is supplied to the image display means 12.

In this example, the correction value Lri is obtained in advance corresponding to the image display means 12, and the correction value Lri is further used to correct the frame by the equation (2) described in the first embodiment. The video signal SOUT having the luminance gradation level L2 ′ in the entire range from 0 gradation to n gradation is calculated. This calculation is performed every time the image display means 12 is manufactured in accordance with the display characteristics of the image display means 12. Therefore, it is preferable that the image display means 12 and the storage means 8 storing the correction value are traded as a set. Of course, trading these as a set is not limited.

FIG. 13 is an image diagram showing an example of the contents of the video signal SOUT of the corrected luminance gradation level L2i 'stored in the storage means 8. For the corrected video signal SOUT of the frame, the luminance gradation level L2i ′ in the entire range from 0 gradation to n gradation is obtained.

The corrected luminance gradation level L2 shown in FIG.
According to the content example of the video signal SOUT of i ′, the brightness gradation levels L11 to L1n (n: gradation) of the video signal SIN ′ of the frame immediately before the current frame are plotted on the horizontal axis, On the vertical axis, the luminance gradation levels L21 to L2n (n: gradation) of the video signal SIN of the current frame are plotted.
In each lattice portion of the matrix formed by the vertical and horizontal luminance gradation levels L11 to L1n and the luminance gradation levels L21 to L2n, the luminance gradation level L in the entire range from 0 gradation to n gradation
The 2'video signal SOUT is stored.

In FIG. 13, the video signal SIN from the 0th gradation to the nth gradation of the current frame is stored as it is in the lattice portion on the diagonal line Aa0 that decreases from the 0th gradation in the upper left portion to the nth gradation in the lower right portion. Done. This is the luminance gradation level L1i of the video signal SIN ′ of the frame immediately preceding the current frame.
And the luminance gradation level L2i of the video signal SIN of the current frame
This is to cope with the case where the difference between and is almost zero.

In the grid part of the upper right area Aa1 which is an example of a specific brightness gradation range of the video signal SIN with reference to the grid part of the diagonal line Aa0, n is calculated from 0 gradation calculated by L2i '= L2i-Lri. The video signal SOUT having the luminance gradation level L2i 'in the entire range up to the gradation is stored. This is to cope with the case where the luminance gradation level L2i of the video signal SIN of the current frame is lower than the luminance gradation level L1i of the video signal SIN ′ of the frame immediately before the current frame. As a result, in the left area Aa1, the video signal SOUT having a lower luminance gradation level than the video signal SIN of the current frame is output.

Further, L2i '= L2i + in the lattice part of the lower left area Aa2 with reference to the lattice part of the diagonal line Aa0.
The video signal SOUT of the luminance gradation level L2i 'in the entire range from 0 gradation to n gradation calculated by Lri is stored. This is compared with the luminance gradation level L1i of the video signal SIN ′ of the frame immediately preceding the current frame, as compared with the luminance gradation level L2i of the video signal SIN of the current frame.
This is to deal with the case where is high. As a result, in the left area Aa2, the video signal SOUT having a higher luminance gradation level than the video signal SIN of the current frame is output.

Next, an operation example of the image display device 205 will be described. FIG. 14 is an image diagram showing an example of reading the video signal SOUT of the corrected luminance gradation level L2i ′ in the storage means 8. FIG. 15 is a flowchart showing an operation example of the image display device 205.

In this embodiment, it is premised that the image display means 12 having a different display response speed depending on the luminance gradation is subjected to display control based on the image signal SIN input for each frame. In addition, a case will be taken as an example in which the reading of the storage unit 8 is controlled based on the noise level in the video signal, and either the video signal SIN before correction or the video signal SOUT after display response speed correction is selected.

In this image display device 205, the video signal SOUT of the corrected luminance gradation level L2i 'as shown in FIG. 13 is stored in the storage means 8 shown in FIG. 12, which is one frame before the current frame. It is assumed that the corrected luminance gradation video signal SOUT is read by using the luminance gradation level L1 of the video signal SIN ′ of the frame and the luminance gradation level L2 of the video signal SIN of the current frame as addresses.

With this as a correction condition, the image signal SIN is stored in the storage means 1 in step C1 of the flowchart shown in FIG.
And the storage means 8. Then, in steps C2 to C4, the response speed improving means 55 corrects the video signal SIN in order to improve the display response speed of the video display means 12.

In this example, the process proceeds to step C2, and the luminance gradation level L1 of the video signal SIN 'of the frame immediately before the current frame and the luminance gradation level L2 of the video signal SIN of the current frame are set as addresses. The corrected luminance gradation video signal SOUT is read. For example, when the luminance gradation level of the video signal SIN of the previous frame shown in FIG. 14 is L1i and the luminance gradation level of the video signal SIN of the current frame is L22 (L22 <L1i), Is the video signal S after the correction of the luminance gradation level calculated by L2i '= L22-Lri.
Outputs OUT (see upper right area).

Further, the luminance gradation level of the video signal SIN of the frame before the current frame shown in FIG. 14 is set to L1i,
The luminance gradation level of the video signal SIN of the current frame is set to L2n.
-2 (L2n-2> L1i), the video signal SOUT of the frame is L2i '= (L2n-2) -Lr.
The corrected video signal SOUT of the brightness gradation level calculated by i is output (see the lower left area).

In parallel with this, in step C3, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is the control device 70.
Is output to. The control device 70 compares the noise level NL with a preset reference value in step C4. When the noise level NL exceeds the reference value, the control device 70 outputs the selection control signal Sc to the selection means 80 and selects the uncorrected video signal SIN in step C5. Since the selecting means 80 selects the video signal SIN before correction based on the selection control signal Sc, this video signal SIN
Is output as is.

As a result, when the noise level NL exceeds the reference value, the drive voltage VOUT generated based on the video signal SIN before correction in the step C7 is used as the video display means 12
To be supplied to. Therefore, in step C8, the image display means 12 displays an image based on the drive voltage VOUT applied for each frame. At this time, the influence of noise can be eliminated by fully utilizing the delay property of the display response speed of the display element when the brightness gradation changes suddenly.

If the noise level NL is less than the reference value, the video signal SOUT corrected by the response speed improving means 55 is selected in step C6. At this time, the control device 70 sends the selection control signal Sc to the selection means 80.
Is output to select the corrected video signal SOUT. Since the selection means 80 selects the corrected video signal SOUT based on the selection control signal Sc, the driving voltage VOUT generated based on the corrected video signal SOUT in step C7 is supplied to the video display means 12. Done.

Therefore, in step C8, the image display means 12
Then, the image display means 12 is driven based on the luminance gradation level L2 ′ of the image signal SIN of the corrected current frame.
In step C9, the power-off information and the like are detected, and the image display processing is ended. If the power-off information or the like is not detected, the process returns to step C1 and the above-mentioned image display processing is continued. As a result, when the noise level NL in the video signal is low or the amount of noise is low, it is possible to improve the delay of the display response speed of the display element when the brightness gradation changes suddenly.

Further, according to this embodiment, when the luminance gradation level L2i of the video signal SIN of the current frame is lower than the luminance gradation level L1i of the video signal SIN 'of the frame immediately before the current frame. Is a video signal SOUT of a lower brightness gradation level obtained by subtracting the correction value Lri from the brightness gradation level L2i of the video signal SIN of the frame,
It can be output from the storage means 8 to the display drive means 11.

The video signal SIN 'of the immediately preceding frame
When the luminance gradation level L2i of the video signal SIN of the current frame is higher than the luminance gradation level L1i of the current frame, a higher luminance level obtained by adding the correction value Lri to the luminance gradation level L2i of the video signal SIN of the frame. The tonal image signal SOUT can be directly output from the storage means 8 to the display drive means 11.

As a result, the image display means 12 does not depend on the correction circuits 3 and 6 as in the first to fourth embodiments.
Even when the liquid crystal display panel is used, it is possible to sufficiently deal with the fast-moving video signal SIN. Moreover, even when an image with a sharp change in brightness is input, the load on the arithmetic control system can be reduced. Further, it is possible to prevent a phenomenon in which the liquid crystal cannot follow the applied voltage and the outline of the image is blurred (sharpness improving function). First to fourth image display devices 2
A liquid crystal television or the like can be constructed at a lower cost than 01-204.

(8) Sixth Embodiment FIG. 16 is a block diagram showing a configuration example of an image display device 206 to which the display control device 106 according to the sixth embodiment of the present invention is applied. In this embodiment, the video signal SIN is divided into high-order bits and low-order bits, and the video signal SOUT having a luminance gradation level L2i 'in the entire range from 0 gradation to n gradation after correction in which only the upper bits are corrected. The video signal SOUT is stored in the read-only storage means 9 such as the correction value lookup table.

In this embodiment, the luminance gradation level L1i of the upper bit video signal SIN of the frame immediately before the current frame and the luminance gradation level L2i of the upper bit video signal SIN of the current frame are used as addresses. Then, the video signal SOUT having the corrected luminance gradation is read out.

Moreover, the noise detecting means 60 and the control device 7
0 and a selection means 80 are provided to control the reading of the storage means 9 based on the noise level NL in the video signal to select either the video signal SIN before correction or the video signal SOUT after display response speed correction. It is something that is done. The same reference numerals and the same names as those in the first to fifth embodiments have the same functions, and the description thereof will be omitted.

The image display device 206 shown in FIG. 16 is a device for controlling the display of the image display means 12 having a different display response speed according to the luminance gradation of the image signal SIN based on the image signal SIN input for each frame. is there. Image display device 206
Has a display control device 106, a display drive means 11 and an image display means 12. The display control device 106 includes a sixth response speed improving means 56, a noise detecting means 60, a control device 70, and a selecting means 80 in order to control the input / output of the display driving means 11.

The response speed improving means 56 is the first storage means 4.
And the second storage means 9, and the storage means 4
In the same manner as in the first embodiment, the video signal SIN 'of the frame immediately before the current frame is stored in the memory.
A RAM or the like is used as the storage unit 4.

Further, the storage means 9 is connected to the storage means 4 and stores the video signal (data) of the upper bit of the corrected optimum luminance gradation level obtained by the correction calculation in advance. A ROM is used as the storage means 9. The luminance gradation level L1 of the video signal SIN of the upper bit of the frame immediately preceding the current frame and the luminance gradation level L2 of the video signal SIN of the upper bit of the current frame are used as addresses for the corrected luminance gradation. This is for reading the video signal SOUT of the upper bits.

The response speed improving means 56 includes the selecting means 8
0 is connected and the video signal SIN before correction or the video signal SOU of the higher order bit after correction obtained by the storage means 9
It is made to choose one of T. Control device 70
Then, for example, the noise level NL detected by the noise detecting means 60 is compared with a preset reference value. The reference value is set by the external control signal CTL.

For example, when the noise level NL exceeds the reference value, the control device 70 selects the video signal SIN before the correction, and when the noise level NL does not reach the reference value, the response speed improving means 55 performs the correction. The selecting means 80 is controlled so as to select the image signal SOUT. The control device 70 outputs the selection control signal Sc to the selection means 80 to select the video signal SIN before correction. This selection means 8
A display drive means 11 is connected to 0, and an applied voltage is supplied to the image display means 12.

A second read-only second storage means 9 is connected to the storage means 4. According to the contents stored in the storage means 9, in the lattice portion on the diagonal line from the upper left 0 gradation to the lower right n gradation shown in FIG. The video signal SIN is stored as it is. In the grid portion in the upper right area shown in FIG. 13, the upper bit video signal SOUT of the luminance gradation level L2i 'in the entire range from 0 gradation to n gradation calculated by L2i' = L2i-Lri is stored. Is done like this.

In the lattice portion in the lower left area shown in FIG. 13, L2
From 0 gradation calculated by i '= L2i + Lri to n
The image signal SOUT of the upper bits of the luminance gradation level L2i 'in the entire range up to the gradation is stored in the storage means 9. As a result, the luminance gradation level L1i of the higher-order bit video signal SIN of the frame immediately preceding the current frame and the luminance gradation level L2i of the higher-order video signal SIN of the current frame stored in the storage unit 4 are calculated. The video signal SOUT of the higher order bits of the corrected luminance gradation of the frame can be read from the storage means 9 as an address.

In the display control device 106, the addition means 7 is connected to the storage means 9 shown in FIG. 16, and the video signal SOUT of the upper bits of the current frame after the correction calculation is added to the lower bit of the current frame before the correction calculation. The video signal SOUT is added and output. Video signal S of current frame after addition
OUT is output to the selection means 80.

In parallel with this, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is output to the control device 70. The control device 70 compares the noise level NL with a preset reference value. When the noise level NL exceeds the reference value, the control device 70 outputs the selection control signal Sc to the selection means 80 to select the uncorrected video signal SIN. Since the selection means 80 selects the video signal SIN before correction based on the selection control signal Sc, this video signal SIN is output as it is.

As a result, when the noise level NL exceeds the reference value, the drive voltage VOUT generated based on the video signal SIN before correction can be supplied to the video display means 12. Therefore, the image display means 12 displays an image based on the drive voltage VOUT applied for each frame. At this time, the influence of noise can be eliminated by fully utilizing the delay property of the display response speed of the display element when the brightness gradation changes suddenly.

When the noise level NL is less than the reference value, the video signal SOUT after the correction by the response speed improving means 56 is selected. At this time, the control device 70 outputs the selection control signal Sc to the selection means 80 to select the corrected video signal SOUT. Since the selecting means 80 selects the corrected video signal SOUT based on the selection control signal Sc, the drive voltage VOUT generated based on the corrected video signal SOUT is supplied to the video display means 12. In the video display means 12, the video display means 12 is driven based on the luminance gradation level L2 ′ of the video signal SIN of the corrected current frame.

Therefore, even when a liquid crystal display panel is used as the image display means 12, it is possible to sufficiently deal with the fast moving image signal SIN as in the fifth embodiment. Moreover, even when an image with a sharp change in brightness is input, it prevents the brightness change, that is, the phenomenon that the liquid crystal cannot follow the applied voltage and the outline of the image is blurred, without burdening the arithmetic control system. it can. The memory capacity of the storage means 4 and the storage means 9 can be reduced as compared with the fifth embodiment.

(9) Application Example FIG. 17 shows a liquid crystal television 300 as an application example according to the present invention.
3 is a block diagram showing a configuration example of FIG. In this application example, a liquid crystal television 300, which is an example of an image display device, is configured and shown in FIG.
Any of the display control devices 101 to 106 described in the first to sixth embodiments is applied to the display control means 10 shown in FIG. In this example, the display controller 105 described in the fifth embodiment is applied to the display control means 10, and the ROM 33 for the correction value lookup table is provided.

In the ROM 33, the luminance gradation level L2i 'in the entire range from 0 gradation to n = 248 gradations is obtained for the corrected video data DOUT of the frame,
These are stored. Then, the luminance gradation level L1i of the video signal SIN ′ of the frame immediately preceding the current frame
And the luminance gradation level L2 of the video signal SIN of the current frame
Video signal SOU with corrected luminance gradation using i as address
By reading T, even when an image with a sharp change in brightness is input, the burden on the arithmetic control system can be further reduced.

The liquid crystal television 300 shown in FIG. 17 receives, for example, an analog ground wave broadcast wave and displays a broadcast program on the liquid crystal display panel 26. The liquid crystal television 300 has an antenna 21 and receives broadcast radio waves from the Yagi antenna 21 or the like. A tuner & IF amplifier 22 is connected to the antenna 21, and NTSC
R (red), G (green), B
The (blue) video signal SIN and the audio signal are detected. An audio amplifier circuit 23 is connected to one side of the tuner & IF amplifier 22, and an audio signal is amplified and output to the speaker 25.

A video amplifier circuit 24 is connected to the other side of the tuner & IF amplifier 22. The video signals of R, G and B (hereinafter simply referred to as video signal SIN) are amplified and the sync signal SY is separated. It The display control means 10 and the display drive means 11 are connected to the image amplification circuit 24. The display control means 10 includes an analog / digital converter (hereinafter referred to as an A / D converter 31), a frame memory 32,
The ROM 33, the CPU 34, the noise detection unit 60, and the selector 80 as an example of the selection unit are provided.

The A / D converter 31 is connected to the video amplifier circuit 24, and is adapted to perform analog-to-digital conversion of the video signal SIN and output R, G, B video data DIN. A frame memory 32, which is an example of a first storage unit, is connected to the A / D converter 31 and stores video data DIN of the frame immediately preceding the current frame.

A ROM 33 for a correction value look-up table, which is an example of a second storage means, is connected to the A / D converter 31 and the frame memory 32, and the ROM 33 for the current frame stored in the frame memory 32 is stored in the frame memory 32. Using the luminance gradation level L1i of the video data DIN of the previous frame and the luminance gradation level L2i of the video data DIN of the current frame as an address, the video data DOUT of the luminance gradation level after correction of the frame is read from the ROM 33. It is read and output.

In the look-up table of the ROM 33, it is assumed that the liquid crystal display panel 26 is intended to perform a display without blur every time the luminance gradation level L2i changes.
It is sufficient that the video data DOUT corrected so as to obtain a brightness gradation level close to the optimum brightness gradation level L2i 'is stored.

A noise detecting means 60 is connected to the A / D converter 31 in addition to the frame memory 32, and the noise level NL is detected from the video signal SIN. Of course, the noise amount may be detected from the video signal SIN.

A CPU 34, which is an example of a control device, is connected to the noise detecting means 60, and a horizontal synchronizing signal HS and a vertical synchronizing signal VS, which are examples of external control signals,
The video signal SIN before correction or the video signal SOUT after correction read from the ROM 33 based on the noise level NL
It is made to choose either.

The CPU 34 generates the writing / reading control signal WE and the reading permission signal OE based on the horizontal synchronizing signal HS and the vertical synchronizing signal VS, outputs the writing / reading control signal WE to the frame memory 32, and outputs 1 of the current frame.
It controls the writing and reading of the video data DIN of the previous frame and outputs the read permission signal OE to the ROM 33 to read the timing of fetching the video data DIN of the current frame and the video data DOUT of one frame after correction. It is designed to control the timing. In this example, the correction calculation in the CPU 34 can be omitted.

A selector 80 is connected to the ROM 33 so as to select either the video signal SIN before correction or the video signal SOUT after correction read from the ROM 33. The CPU 34 compares the noise level NL detected by the noise detection means 60 with a preset reference value, for example.

The reference value is set by the external control signal CTL. For example, the CPU 34 selects the video signal SIN before correction when the noise level NL exceeds the reference value, and selects the video signal SOUT after correction by the display response speed correction circuit when the noise level NL does not reach the reference value. To control the selector 80.

Further, the display drive means 11 is connected to the above-mentioned video amplification circuit 24. The display driving means 11 includes a horizontal synchronizing circuit 41, a vertical synchronizing circuit 42, and a scan electrode driving circuit 4.
3 and a signal electrode drive circuit 44. An active matrix type liquid crystal display panel 26, which is an example of an image display unit, is connected to the scan electrode drive circuit 43 and the signal electrode drive circuit 44.

The horizontal synchronizing circuit 41 is connected to one of the video amplifier circuits 24, and the horizontal synchronizing signal HS is detected from the synchronizing signal SY. The vertical synchronizing circuit 42 is connected to the other side of the video amplifier circuit 24, and the vertical synchronizing signal VS is detected from the synchronizing signal SY. The horizontal synchronization signal HS and the vertical synchronization signal VS are output to the CPU 34, the horizontal synchronization signal HS is output to the scan electrode drive circuit 43, and the vertical synchronization signal VS is output to the signal electrode drive circuit 44.

The horizontal synchronizing circuit 41 includes the scan electrode driving circuit 4
3 are connected, and the liquid crystal display panel 26 is line-sequentially scanned based on the horizontal synchronizing signal HS. A plasma drive driver IC or the like is used for the scan electrode drive circuit 43. The vertical synchronizing circuit 42 includes the signal electrode driving circuit 4
4 are connected, a drive voltage is generated based on the vertical synchronizing signal VS and the corrected video data DOUT, and the drive voltage is supplied to the liquid crystal display panel 26.

A data driver IC compatible with plasma driven column inversion is used for the signal electrode drive circuit 44.
A backlight 27 is attached to the back surface of the liquid crystal display panel 26. Of course, the liquid crystal television 300 is provided with the power supply unit 28 so as to supply power to the backlight 27 and each functional circuit.

Next, an example of the contents of the ROM 33 will be described. FIG. 18 is an image diagram showing an example of the contents of the video data DOUT of the corrected luminance gradation level L2i ′ stored in the ROM 33, and FIG. 19 shows the correction value Lri of the video data DOUT shown in FIG. 18 for each equal level. It is the image figure which displayed by color.

In the ROM 33 of this example, 8 gradations are set as one unit, and the corrected gradation gradation level L2 of 0 to 248 gradations is set.
Video data DOUT of i'is stored, and according to the content example, video data DIN of i = 0 to 248 gradations is plotted as the brightness gradation level L1i one frame before on the horizontal axis shown in FIG. Video data DIN with i = 0 to 248 gradations is plotted on the vertical axis as the brightness gradation level L2i of the current frame. Image data DOUT of luminance gradation level L2i ′ in the entire range from 0 gradation to 248 gradations is stored in each lattice portion of the matrix formed by the vertical and horizontal 1-frame previous video data DIN and the current frame video data DIN. To be done.

[0167] In this example of the contents, 0 gradation in the upper left portion to 24 in the lower right portion
In the grid portion on the diagonal line Aa0 that decreases to 8 gradations, 0, 8, 16, from the 0th gradation of the current frame to the 248th gradation,
The image data DIN of 24, 32, 40 ... 240, 248 gradations are stored as they are. This is 1
The luminance gradation level L1i of the video data DIN before the frame and the luminance gradation level L2i of the video data DIN of the current frame
This is to cope with the case where the difference between and is almost zero.

On the basis of the grid portion of the diagonal line Aa0, L2 is set in the grid portion of the upper right area Aa1 of the video data DIN.
i ′ = L2 2 from 0 gradation calculated by i-Lri
The video data DINDOUT of the luminance gradation level L2i 'in the entire range up to 48 gradations is stored. This is 1
This is to cope with the case where the luminance gradation level L2i of the video data DIN of the current frame is lower than the luminance gradation level L1i of the video data DIN before the frame. In the upper right area Aa1, the video data DOUT having a luminance gradation level L2i ′ lower than the video data DIN of the current frame is output.

Further, in the lattice part of the lower left area Aa2 with reference to the lattice part of the diagonal line Aa0, L2i '= L2i +
The image data DOUT of the luminance gradation level L2i 'in the entire range from 0 gradation to 248 gradation calculated by Lri is stored. This is to cope with the case where the brightness gradation level L2i of the video data DIN of the current frame is higher than the brightness gradation level i of the video data DIN one frame before. In the lower left area Aa2, the luminance gradation level L is higher than the video data DIN of the current frame.
The 2i 'video data DOUT is output.

The upper right area Aa1 and the lower left area Aa2 described above.
For the correction value Lri in the liquid crystal display panel 26,
Depending on the display characteristics of, 8, 16, 24, 32, 40,
48, 56, and 64 gradations are applied. In this example, particularly in the case of the intermediate gradation, the luminance gradation level is lowered from the upper gradation level to the lower gradation level, and a larger correction value is applied as the reduction width is larger.

For example, if the luminance gradation level L1 of the video data DIN one frame before is i = “72” and the luminance gradation level L2 of the video data DIN of the current frame is i = “88”, then the corrected data is obtained. I as the video data DIN of the current frame
The luminance gradation level L2 ′ of “96” is read. The correction value Lri at this time is +8.

Similarly, L1 = “72” and L2 =
In the case of “104”, L2 ′ = “128” is read. The correction value Lri at this time is +24. L1 = “7
2 ”, and when L2 =“ 120 ”, L2 ′ =“ 152 ”
Is read. The correction value Lri at this time is +32. If L1 = “72” and L2 = “128”, then L
2 ′ = “168” is read. Correction value Lr at this time
i is +40. In any case, the liquid crystal display panel 2
This is to improve the delay of the response time when lowering the luminance gradation level from the upper gradation level to the lower gradation level in 6 in the intermediate gradation.

Further, in the case of increasing the luminance gradation level from the lower gradation level to the upper gradation level, a larger correction value is applied as the increase range is larger. For example, the luminance gradation level L1 of the video data DIN one frame before is i =
When the luminance gradation level L2 of the video data DIN of the current frame is i = “72” at “160”, the luminance gradation level L2 ′ of i = “8” is read as the video data DIN of the corrected current frame. Be done. The correction value Lri at this time is -6.
It is 4.

Similarly, L1 = “160” and L2 =
In the case of “80”, L2 ′ = “24” is read. The correction value Lri at this time is -56. L1 = “160”
Then, when L2 = “96”, L2 ′ = “48” is read. The correction value Lri at this time is -48. L1 =
In the case of “160” and L2 = “104”, L2 ′ = “6”
4 ”is read. The correction value Lri at this time is -40.

When L1 = “160” and L2 = “120”, L2 ′ = “88” is read. The correction value Lri at this time is -32. L1 = “160” and L2 =
In the case of “136”, L2 ′ = “112” is read. The correction value Lri at this time is -24. L1 = “1
60 ", and when L2 =" 144 ", L2 '=" 12 "
8 ”is read. The correction value Lri at this time is -16.

In any case, this is to improve the delay of the response time when the brightness gradation level is raised from the lower gradation level to the upper gradation level in the intermediate gradation in the liquid crystal display panel 26.

FIG. 20 shows L1 in the ROM 33.
It is an image figure of the three-dimensional reference table which shows the example of a relation of i, L2i, and Lri. Since the viewing angle of the three-dimensional lookup table is changed, the values do not always match the values in the lookup table shown in FIG. In FIG. 20, L1i is the luminance gradation level of 0 to 248 of the video data DIN one frame before, and L2i is 0 of the video data DIN of the current frame.
~ 248 luminance gradation levels, and Lri is a correction value 0 to 64 gradations at that time.

That is, on the liquid crystal display panel 26, the video data DOUT of the current frame is prepared so that the video data DIN of the next frame can be quickly changed to the luminance gradation level L2i with respect to the video data DIN of the previous frame. . Alternatively, when there is a brightness gradation level L2i having a faster display response speed near the brightness gradation level L2i desired to be changed in the characteristics of the liquid crystal display panel 26, the brightness gradation level L2i is changed to the brightness gradation level L2i. The corrected image data DOUT is prepared.

Subsequently, an operation example of the liquid crystal television 300 will be described. In this example, the liquid crystal television 3 shown in FIG.
00, the corrected video data D described in FIG.
It is premised that OUT is stored in the ROM 33 and an NTSC broadcast program is displayed on the liquid crystal display panel 26. Of course, power is supplied to the backlight 27 on the back surface of the liquid crystal display panel 26, and power is supplied to each functional circuit.

When the analog terrestrial broadcast radio wave is received by the antenna 21 shown in FIG. 17 under these operating conditions, the NTSC system broadcast radio wave is output from the antenna 21 to the tuner & IF amplifier 22. tuner&
The IF amplifier 22 processes the broadcast radio wave to detect the audio signal and the R, G, B video signals SIN. The audio signal is amplified by the audio amplifier circuit 23 and output to the speaker 25.

The R, G and B video signals (video signal SIN) are amplified by the video amplifier circuit 24 and the sync signal SY is separated. The horizontal synchronizing circuit 41 detects the horizontal synchronizing signal HS from the synchronizing signal SY, and the vertical synchronizing circuit 42 detects the vertical synchronizing signal VS from the synchronizing signal SY. The horizontal synchronization signal HS and the vertical synchronization signal VS are output to the CPU 34, the horizontal synchronization signal HS is output to the scan electrode drive circuit 43, and the vertical synchronization signal VS is output to the signal electrode drive circuit 44.

The video signal SIN is amplified by the video amplifier circuit 24 and then analog-to-digital converted by the A / D converter 31 to become R, G, B video data DIN. The video data DIN of the frame immediately preceding the current frame is stored in the frame memory 32. Current frame video data DIN
And the video data D read from the frame memory 32
IN is input to the ROM 33 for the correction value lookup table based on the write / read control signal WE.

In the ROM 33, the video data D of the frame immediately before the current frame stored in the frame memory 32.
The brightness gradation level L1i of IN and the brightness gradation level L2i of the video data DIN of the current frame are used as addresses, and the video data DOUT of the brightness gradation level after the correction of the frame.
Is read. The ROM 33 can correct the video data DOUT according to the change in the luminance gradation level of the video signal SIN.

In parallel with this, noise is detected from the video signal SIN by the noise detecting means 60. The noise level NL detected here is output to the CPU 34. CP
At U34, the noise level NL is compared with a preset reference value. When the noise level NL exceeds the reference value, the CPU 34 outputs the selection control signal Sc to the selector 80 to select the video signal SIN before correction. Since the selector 80 selects the video signal SIN before correction based on the selection control signal Sc, this video signal SIN
Is output as is.

As a result, when the noise level NL exceeds the reference value, the drive voltage VOUT generated based on the video signal SIN before correction can be supplied to the signal electrode drive circuit 44. On the other hand, in the scan electrode drive circuit 43, the liquid crystal display panel 26 is line-sequentially scanned based on the horizontal synchronizing signal HS. Therefore, in the liquid crystal display panel 26,
An image is displayed based on the drive voltage VOUT applied for each frame. At this time, the influence of noise can be eliminated by fully utilizing the delay property of the display response speed of the display element when the brightness gradation changes suddenly.

If the noise level NL is less than the reference value, the corrected video signal SOUT read from the ROM 33 is selected. At this time, CPU3
The selector 4 outputs the selection control signal Sc to the selector 80 to select the corrected video signal SOUT.

Since the selector 80 selects the corrected video signal SOUT based on the selection control signal Sc, the drive voltage VOUT generated by the signal electrode drive circuit 44 based on the vertical synchronizing signal VS and the corrected video signal SOUT. Are supplied to the liquid crystal display panel 26.

The liquid crystal display panel 26 is driven based on the luminance gradation level L2 'of the video signal SIN of the corrected current frame. For example, from a certain luminance gradation level L1i,
When the luminance gradation level L2i is lower than that,
If the response time of the liquid crystal display panel 26 is slow, the luminance gradation level of the video data DIN is lowered and the change of the drive voltage is increased. On the liquid crystal display panel 26, even a rapidly moving NTSC broadcast program is displayed in high definition.

In this way, according to the liquid crystal television 300 as an application example of the present invention, the display control device 105 according to the fifth embodiment described above is applied, and therefore, when the brightness gradation level changes, The corrected video data DOUT can be replaced with the video data DIN of the previous frame and the video data DIN of the current frame, the brightness gradation level being corrected to be optimum on the liquid crystal display panel 26.

Further, the ROM 34 can be operated without burdening the CPU 34 or the like with the calculation load relating to the luminance gradation of the video data DIN.
Since the corrected video data DIN can be output by means of, the liquid crystal display panel 26 can quickly move the video data D.
It becomes possible to deal with OUT sufficiently. Therefore, even when the image data DOUT having a large change in brightness is input to the signal electrode drive circuit 44, it is possible to prevent the change in brightness, that is, the phenomenon that the liquid crystal cannot follow the applied voltage and the outline of the image is blurred.

In this application example, the case where the display control device 105 according to the fifth embodiment is used for the display control means 10 has been described, but the present invention is not limited to this, and the first
The display control devices 101 to 104 according to the fourth embodiment and the display control device 106 according to the sixth embodiment can be used.

By using the correction value look-up table in these display control devices 105 and 106, the correction value can be read out for each change of the video data DIN of various luminance gradation levels L2i, and no overcorrection occurs. Thus, the correction value Lri can be finely adjusted. It is possible to make the response time constant with high accuracy in all changes in the luminance gradation level L2i. Further, even when the liquid crystal display panel 26 having different display response speeds with respect to the drive voltage is used, it is possible to easily cope with it by exchanging the lookup data.

Further, in the application example, the case where one look-up table ROM 33 is provided in the display control means 10 has been described, but the present invention is not limited to this, and, for example, a plurality of look-up table ROMs corresponding to temperature changes. You may make it provide ROM. This look-up table is a table in which the correction value corresponding to the temperature change is calculated in advance to the video data of the brightness gradation level of the frame, and the temperature-dependent correction gradation data after the calculation is made into a reference table.

The display control means 10 switches the reading of the temperature-dependent gradation data according to the operating environment temperature. When the liquid crystal display panel 26 is driven with the temperature-dependent correction gradation data, it is possible to eliminate the variation in the response time of the liquid crystal due to the ambient temperature of the backlight 27 and the like and make it constant.

In the application example described above, the case of the liquid crystal television (LCDTV) has been described as the image display device.
The display control devices 103 to 104 are similarly PALC, LCD
It can be applied to PJ and the like, and also to plasma display (PDP).

[0196]

As described above, according to the display control device of the present invention, when the display control of the matrix type display element having the different display response speed corresponding to the luminance gradation is performed based on the video signal. A noise detection unit that detects noise from the video signal is provided, and either the video signal before correction or the video signal after correction is output based on the noise level detected here.

With this configuration, when the noise level in the video signal is large or the noise amount is large, the video signal before correction can be output as it is to the display element, and the display of the display element when the brightness gradation suddenly changes. The effect of noise can be eliminated by making full use of the delay in response speed.

Further, when the noise level in the video signal is small or the noise amount is small, the corrected video signal can be output to the display element, and the display response speed of the display element at the time of a sudden change in luminance gradation can be reduced. Delayability can be improved.

According to the image display device of the present invention, the image display device has a matrix type display element having a different display response speed corresponding to the luminance gradation and displays an image based on the drive voltage applied for each frame. In the case of displaying, the display control device described above is applied.

With this configuration, when the noise level in the video signal is large or the noise amount is large, the video signal before correction can be output to the display element as it is, and the display element displays when the brightness gradation suddenly changes. The effect of noise can be eliminated by making full use of the delay in response speed.

When the noise level in the video signal is small or the noise amount is small, the corrected video signal can be output to the display element, and the display response speed of the display element at the time of a sudden change in luminance gradation can be reduced. Delayability can be improved.

The present invention provides a PALC or LCDT which supplies a video signal for each frame to an image display device having a different display response speed corresponding to a luminance gradation to display an image.
It is very suitable when applied to V, LCDPJ and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a display control device 100 as a first embodiment according to the present invention.

FIG. 2 is a block diagram showing a configuration example of noise detection means 60.

FIG. 3 is a flowchart showing an operation example of the display control device 100 according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration example of a display control device 200 as a second embodiment according to the present invention.

FIG. 5 is a block diagram showing a configuration example of an image display device 201 to which the display control device 101 according to the first embodiment of the present invention is applied.

FIG. 6 is a diagram of luminance gradation levels showing an example of correction processing in the correction circuit 3;

FIG. 7 is a block diagram showing a configuration example of an image display device 202 to which a display control device 102 as a second embodiment according to the present invention is applied.

FIG. 8 is an image diagram showing an example of contents of a reference table in a storage means (ROM) 2.

9 is a flowchart showing an operation example of the image display device 202. FIG.

FIG. 10 is a block diagram showing a configuration example of an image display device 203 to which a display control device 103 as a third embodiment according to the present invention is applied.

FIG. 11 is a block diagram showing a configuration example of an image display device 204 to which a display control device 104 as a fourth embodiment according to the present invention is applied.

FIG. 12 is a block diagram showing a configuration example of an image display device 205 to which a display control device 105 as a fifth embodiment according to the present invention is applied.

FIG. 13 is an image diagram showing an example of contents of a video signal SOUT of a corrected luminance gradation level L2i ′ stored in a storage means 8.

FIG. 14 is an image diagram showing an example of reading a video signal SOUT of a corrected luminance gradation level L2i ′ in a storage means 8.

FIG. 15 is a flowchart showing an operation example of the image display device 205.

FIG. 16 is a block diagram showing a configuration example of an image display device 206 to which a display control device 106 as a sixth embodiment according to the present invention is applied.

FIG. 17 is a liquid crystal television 30 as an application example according to the present invention.
It is a block diagram which shows the structural example of 0.

FIG. 18 is an image diagram showing an example of contents of the ROM 33 relating to the video data DOUT of the corrected luminance gradation level L2i ′.

FIG. 19 is a correction value L of the video data DOUT shown in FIG.
It is an image figure of an example of the contents of ROM33 which displayed ri for each equivalent level in different colors.

FIG. 20 shows L1i, L2i, and Lr in the ROM 33.
It is an image figure of the three-dimensional reference table which shows the relation example of i.

[Description of Reference Signs] 1,4 ... First storage means, 2, 5, 8, 9 ... Second storage means, 3, 6 ... Correction circuit, 7 ... Addition means, 10 ... Display control means, 11 ... Display drive means, 12 ... Image display means, 32 ... Frame memory (first storage means), 33 ... ROM (second storage means), 34 ... CPU (control device), 50-56.
..Response speed improving means, 60 ... Noise detecting means, 7
0 ... Control device, 101-106 ... Display control device (display control means), 201-206 ... Image display device, 300 ... Liquid crystal television (Image display device)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 631 G09G 3/20 631B 631V 641 641R 660 660W H04N 5/66 102 H04N 5/66 102B F term (Reference) 2H093 NA16 NA45 NA51 NC11 NC13 NC16 NC24 NC34 NC41 NC52 NC57 NC63 ND32 ND34 ND60 NE03 NE06 NE07 NE10 5C006 AA01 AA16 AA22 AC21 AF04 AF06 AF13 AF45 AF46 BB16 BC16 BF02 BF08 FA14 FA19 FA29 FA08 BA35 BA02 BA33 BA02 BA08 5C058 A33 AA10 BB05 CC03 DD08 EE19 EE29 FF11 FF12 GG08 GG12 GG17 JJ02 JJ07 KK43

Claims (27)

[Claims] 1. A device for controlling the display of a matrix type display element, which has a different display response speed according to the luminance gradation of a video signal, comprising: a video signal of a previous frame and a video signal of a current frame. Noise detecting means for calculating a noise level by calculating a difference, and correcting the brightness gradation of the video signal based on the noise level obtained by the noise detecting means, or the brightness gradation relating to the video signal prepared in advance Display response speed improving means for selecting display data to improve the display response speed of the display element, and based on the noise level of the video signal detected by the noise detecting means, the display response speed improving means before correction A display control device, wherein a corrected video signal including a video signal is output. 2. A controller for variably setting the correction amount based on the noise level detected by the noise detecting means, in the case of correcting the luminance gradation of the video signal in accordance with a predetermined correction amount. The display control device according to claim 1, further comprising: 3. A selection means for selecting any one of output candidates of a plurality of corrected video signals including the video signal before correction or the video signal before correction prepared by the display response speed improving means, and A control device that compares the noise level detected by the noise detection means with a preset reference value, wherein the control device selects the video signal before correction when the noise level exceeds the reference value. If the noise level is less than a reference value, the selecting means is controlled to select one of the corrected video signals including the uncorrected video signal output from the display response speed improving means. The display control device according to claim 1. 4. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, and stores at least the video signal of a frame immediately before the current frame. And a difference between the brightness gradation of the video signal of the immediately preceding frame stored in the first storage means and the brightness gradation of the video signal of the current frame stored in the first storage means, and corresponding to the difference. The display control device according to claim 1, further comprising a correction circuit that calculates and outputs the corrected value to a luminance gradation of a video signal of the current frame. 5. The display control device according to claim 4, further comprising a second storage unit that stores a correction value corresponding to the difference. 6. The correction circuit, when the difference between the brightness gradation of the video signal of the immediately preceding frame stored in the first storage means and the brightness gradation of the video signal of the current frame is substantially zero. Outputs the video signal of the current frame as it is, and with respect to the specific luminance gradation range of the video signal, as compared with the luminance gradation of the video signal of the previous frame stored in the first storage means. When the brightness gradation of the video signal of the current frame is low, a video signal of a lower brightness gradation obtained by subtracting the correction value from the brightness gradation of the video signal of the current frame is output and stored in the first storage means. If the brightness gradation of the video signal of the current frame is lower than the brightness gradation of the video signal of the immediately preceding frame, a higher brightness level obtained by adding a correction value to the brightness gradation of the video signal of the current frame. To output a tonal video signal The display control device according to claim 4, symptoms. 7. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, wherein the video signal of at least the upper bit of the frame immediately before the current frame. And a luminance gradation of a video signal of an upper bit of a frame immediately preceding the current frame stored in the first storage means, and a luminance of a video signal of an upper bit of the current frame. The difference with the gradation is calculated, and the correction value corresponding to the difference is calculated as the brightness gradation of the video signal of the higher-order bit of the current frame, and the correction value is calculated to the video signal of the higher-order bit of the current frame after the correction calculation. 2. The display control device according to claim 1, further comprising: a correction circuit that adds and outputs the video signals of the lower bits of the current frame. 8. The display control device according to claim 7, further comprising a second storage unit that stores a correction value corresponding to the difference. 9. The correction circuit sets the luminance gradation of the upper-bit video signal of the immediately preceding frame and the luminance gradation of the higher-bit video signal of the current frame stored in the first storage means. If the difference is almost zero,
The high-order bit video signal of the current frame is output as it is, and with respect to the specific luminance gradation range of the video signal, the luminance level of the high-order bit video signal of the immediately preceding frame stored in the first storage means. If the luminance gradation of the higher-order bit video signal of the current frame is lower than that of the tone, a lower luminance gradation higher-order video signal obtained by subtracting the correction value from the luminance gradation of the higher-order bit video signal of the current frame. Is output, and if the luminance gradation of the upper-bit video signal of the current frame is higher than the luminance gradation of the upper-bit video signal of the immediately preceding frame stored in the first storage unit, 8. The display control device according to claim 7, wherein a video signal of a higher luminance gradation upper bit, which is obtained by adding a correction value to the luminance gradation of the upper bit video signal of the frame, is output. 10. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, and stores at least the video signal of a frame immediately before the current frame. The first storage means and the brightness gradation of the video signal of the immediately preceding frame and the brightness gradation of the video signal of the current frame stored in the first storage means are used as addresses to correct the frame. The display control device according to claim 1, further comprising a second storage unit that outputs a video signal of a brightness gradation. 11. A case where a correction value is obtained in advance corresponding to a display response speed of the display element, wherein the second storage unit stores the correction value before the correction value stored in the first storage unit. When the difference between the brightness gradation of the video signal of the frame and the brightness gradation of the video signal of the current frame is substantially zero, the video signal of the current frame is stored as it is, and the specific brightness gradation of the video signal is stored. Regarding the range, when the brightness gradation of the video signal of the current frame is lower than the brightness gradation of the video signal of the frame immediately before stored in the first storage means, the brightness of the video signal of the current frame A video signal of a lower brightness gradation obtained by subtracting the correction value from the gradation is stored, and the video of the current frame is compared with the brightness gradation of the video signal of the previous frame stored in the first storage means. Signal brightness gradation is low If the display control device according to claim 10, characterized in that higher luminance gradation of the image signal obtained by adding the correction value to the luminance gradation of the image signal of the current frame is stored. 12. The display response speed improving means corrects the luminance gradation of a video signal input for each frame, wherein the video signal of at least the upper bit of the frame immediately before the current frame. And a brightness gradation of the video signal of the higher-order bit of the immediately preceding frame and a brightness gradation of the video signal of the higher-order bit of the current frame stored in the first storage means. Second storage means for outputting the video signal of the corrected luminance gradation of the frame as an address, and the video signal of the upper bit of the current frame before correction to the video signal of the higher bit of the current frame after correction The display control device according to claim 1, further comprising: an addition unit that performs addition. 13. A case where a correction value is obtained in advance corresponding to a display response speed of the display element, wherein the second storage unit stores the correction value immediately before the correction value stored in the first storage unit. When the difference between the brightness gradation of the video signal of the upper bit of the frame and the brightness gradation of the video signal of the current frame is substantially zero, the video signal of the higher bit of the current frame is stored as it is. The luminance gradation of the video signal of the upper bit of the current frame compared to the luminance gradation of the video signal of the upper bit of the frame one frame before stored in the first storage means. Is low, the video signal of a lower luminance gradation upper bit obtained by subtracting the correction value from the luminance gradation of the upper bit video signal of the current frame is stored, and one stored in the first storage means is stored. Previous frame If the luminance gradation of the upper-bit video signal of the current frame is higher than that of the upper-bit video signal of the current frame, a correction value is added to the luminance gradation of the upper-bit video signal of the current frame. 13. The display control device according to claim 12, wherein a video signal of high luminance gradation upper bits is stored. 14. A video display unit having a matrix type display element having a different display response speed corresponding to the luminance gradation of a video signal, and displaying an image based on a drive voltage applied for each frame. A display drive unit that supplies an applied voltage to the image display unit; and a display control unit that controls input and output of the display drive unit, wherein the display control unit includes a video signal of a previous frame and a current frame. Noise detecting means for calculating a difference from the video signal to detect the noise level, and correcting the luminance gradation of the video signal based on the noise level obtained by the noise detecting means, or a video signal prepared in advance And a display response speed improving means for improving the display response speed of the display element by selecting the luminance gradation data according to (1), and the noise level of the video signal detected by the noise detecting means. An image display device, wherein a corrected video signal including a video signal before correction is output from the display response speed improving means on the basis of the video signal. 15. The case where the display response speed improving means corrects the luminance gradation of the video signal in accordance with a predetermined correction amount, and the display is performed based on the noise level detected by the noise detecting means. The image display device according to claim 14, further comprising a control device that variably sets a correction amount of the response speed improving means. 16. Selection means for selecting any one of output candidates of a plurality of corrected video signals including the video signal before correction or the video signal before correction prepared by the display response speed improving means, and A control device that compares the noise level detected by the noise detection means with a preset reference value, wherein the control device selects the video signal before correction when the noise level exceeds the reference value. If the noise level is less than a reference value, the selecting means is controlled to select one of the corrected video signals including the uncorrected video signal output from the display response speed correction circuit. The image display device according to claim 14, wherein: 17. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, and stores at least the video signal of a frame immediately before the current frame. And a difference between the brightness gradation of the video signal of the immediately preceding frame stored in the first storage means and the brightness gradation of the video signal of the current frame stored in the first storage means, and corresponding to the difference. 15. The image display device according to claim 14, further comprising a correction circuit that calculates and outputs the correction value to the brightness gradation of the video signal of the current frame. 18. The image display device according to claim 17, further comprising a second storage unit that stores a correction value corresponding to the difference. 19. The correction circuit, when the difference between the luminance gradation of the video signal of the immediately preceding frame stored in the first storage means and the luminance gradation of the video signal of the current frame is substantially zero. Outputs the video signal of the current frame as it is, and with respect to the specific luminance gradation range of the video signal, compared with the luminance gradation of the video signal of the previous frame stored in the first storage means. When the brightness gradation of the video signal of the current frame is low, a video signal of a lower brightness gradation obtained by subtracting the correction value from the brightness gradation of the video signal of the current frame is output and stored in the first storage means. If the brightness gradation of the video signal of the current frame is lower than the brightness gradation of the video signal of the immediately preceding frame, a higher brightness level obtained by adding a correction value to the brightness gradation of the video signal of the current frame. To output a tonal video signal The image display apparatus according to claim 17, wherein. 20. The display response speed improving means corrects the luminance gradation of a video signal input for each frame, wherein the video signal of at least the upper bit of the frame immediately before the current frame. And a luminance gradation of a video signal of an upper bit of a frame immediately preceding the current frame stored in the first storage means, and a luminance of a video signal of an upper bit of the current frame. The difference with the gradation is calculated, and the correction value corresponding to the difference is calculated as the brightness gradation of the video signal of the higher-order bit of the current frame, and the correction value is calculated to the video signal of the higher-order bit of the current frame after the correction calculation. 15. The image display device according to claim 14, further comprising a correction circuit that adds and outputs the video signals of the lower bits of the current frame. 21. The image display device according to claim 20, wherein the display response speed improving unit includes a second storage unit that stores a correction value corresponding to the difference. 22. The correction circuit sets the luminance gradation of the upper-bit video signal of the immediately preceding frame and the luminance gradation of the higher-bit video signal of the current frame stored in the first storage means. If the difference is almost zero,
The high-order bit video signal of the current frame is output as it is, and with respect to the specific luminance gradation range of the video signal, the luminance level of the high-order bit video signal of the immediately preceding frame stored in the first storage means. If the luminance gradation of the higher-order bit video signal of the current frame is lower than that of the tone, a lower luminance gradation higher-order video signal obtained by subtracting the correction value from the luminance gradation of the higher-order bit video signal of the current frame. Is output, and if the luminance gradation of the upper-bit video signal of the current frame is higher than the luminance gradation of the upper-bit video signal of the immediately preceding frame stored in the first storage unit, 21. The image display device according to claim 20, wherein the image display device outputs a higher-luminance gradation upper-bit video signal obtained by adding a correction value to the luminance gradation of the higher-order video signal of the frame. 23. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, and stores at least a video signal of a frame immediately before the current frame. The first storage means and the brightness gradation of the video signal of the immediately preceding frame and the brightness gradation of the video signal of the current frame stored in the first storage means are used as addresses to correct the frame. The image display device according to claim 14, further comprising a second storage unit that outputs a video signal having a brightness gradation. 24. A case where a correction value is obtained in advance corresponding to a display response speed of the display element, wherein the second storage unit stores the correction value immediately before the correction value stored in the first storage unit. When the difference between the brightness gradation of the video signal of the frame and the brightness gradation of the video signal of the current frame is substantially zero, the video signal of the current frame is stored as it is, and the specific brightness gradation of the video signal is stored. Regarding the range, when the luminance gradation of the video signal of the current frame is lower than the luminance gradation of the video signal of the immediately preceding frame stored in the first storage means, the luminance of the video signal of the current frame A video signal of a lower brightness gradation obtained by subtracting the correction value from the gradation is stored, and the video of the current frame is compared with the brightness gradation of the video signal of the previous frame stored in the first storage means. Signal brightness gradation is low If the image display apparatus according to claim 23, characterized in that higher luminance gradation of the image signal obtained by adding the correction value to the luminance gradation of the image signal of the current frame is stored. 25. The display response speed improving means is for correcting the luminance gradation of a video signal input for each frame, wherein at least the video signal of the upper bit of the frame immediately preceding the current frame. And a brightness gradation of the video signal of the higher-order bit of the immediately preceding frame and a brightness gradation of the video signal of the higher-order bit of the current frame stored in the first storage means. Second storage means for outputting the video signal of the corrected luminance gradation of the frame as an address, and the video signal of the upper bit of the current frame before correction to the video signal of the higher bit of the current frame after correction 15. The image display device according to claim 14, further comprising addition means for performing addition. 26. A case in which a correction value is obtained in advance corresponding to a display response speed of the display element, wherein the second storage unit stores the correction value immediately before the one stored in the first storage unit. When the difference between the brightness gradation of the video signal of the upper bit of the frame and the brightness gradation of the video signal of the current frame is substantially zero, the video signal of the higher bit of the current frame is stored as it is. The luminance gradation of the video signal of the upper bit of the current frame compared to the luminance gradation of the video signal of the higher bit of the immediately preceding frame stored in the first storage means. Is low, the video signal of a lower luminance gradation upper bit obtained by subtracting the correction value from the luminance gradation of the upper bit video signal of the current frame is stored, and one stored in the first storage means is stored. Previous frame If the luminance gradation of the upper-bit video signal of the current frame is higher than that of the upper-bit video signal of the current frame, a correction value is added to the luminance gradation of the upper-bit video signal of the current frame. 26. The image display device according to claim 25, wherein the image signal of high luminance gradation upper bits is stored. 27. The display control means is provided with a plurality of look-up tables after calculating a correction value corresponding to a temperature change into a video signal of a luminance gradation of the frame, and temperature dependence depending on a use environment temperature. 15. The image display device according to claim 14, wherein reading of gradation data is switched.