JP2000194318A - Display device and display method for preventing false contour of moving picture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve troubles due to a false contour of a moving picture by detecting a picture on which a false contour of a moving picture is to be easily generated from a change in the data bits of a video signal, reducing the number of gradations in the video signal and controlling an on-period and a writing period. SOLUTION: A detection part 22 compares video data inputted from a data input part 10 with video data stored in a frame storage part 21 in each pixel, and when the video data are changed from a most significant bit(MSB) to an (MSB-1) bit or changed from the (MSB-1) bit to the MSB, outputs a signal indicating the change to a result comparing part 23. A sub-field development changing part 24 receives information from the comparing part 23 and changes the development of a sub-field included in one field period. When the count number of the video data which is, obtained from the comparing part 23 is larger than a threshold, the video data inputted from the data input part 10 are changed to data adapted to gradation expressed by one field period and written in a video data recording table 252.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving image false contour prevention display device and a moving image false contour preventing display method for improving a moving image false contour generated in a display device using a subfield method in a plasma display or the like.

[0002]

2. Description of the Related Art In a plasma display or the like which performs display using a memory effect, a subfield method is used to perform a gray scale display. In this method, for example, in order to realize a display of 64 gradations, the brightness of each pixel is digitized into a 6-bit luminance signal corresponding to gradation luminance data having luminance twice different from each other and stored. The MSB, which is the bit with the highest luminance, is B1, and the following bits are B3 to
When B6 is displayed, the luminance ratio of each bit is 32:16:
8: 4: 2: 1. By selecting these bits, it is possible to display 64 gradations corresponding to luminance levels of 0 to 63.

In a plasma display, an image is sequentially reproduced in six subfields weighted by the number of times of light emission corresponding to each bit in one field period, and a natural halftone image is obtained by a visual integration effect. However, in such a subfield method, although a good gradation display is reproduced in the case of a still image, a moving image false contour occurs in a moving image. In addition, when a false contour of a moving image occurs, a color shift, a sense of reduction in resolution, and the like are caused. Here, the moving image false contour means that, for example, when an image whose brightness changes smoothly moves on the screen, a dark contour or a bright contour appears in a portion that should be a smooth image. Such a false contour of a moving image is conspicuously generated at a boundary where a luminance signal is shifted to an upper bit in a smooth gradation change, thereby significantly deteriorating display quality.

In order to solve such a problem, for example, in Japanese Patent Laid-Open Publication No. Hei 3-145691, a subfield of the next highest bit and a subfield of the next bit are placed on both sides of the subfield of the highest bit. By arranging them, the problem due to the false contour of the moving image is improved.

[0005] In addition, the invention of a "gradation display method of a display device" disclosed in JP-A-8-254965 and the "gradation display method of a display device" disclosed in JP-A-10-124001 are disclosed. In each case, the arrangement of the subfields in the field period is changed to improve the problem caused by the false contour of the moving image.

Furthermore, in the invention of "gradation display method and gradation display device" disclosed in Japanese Patent Application Laid-Open No. 10-153982, the luminance of a subfield in a field period is set to a factor other than the factorial of 2. The problem caused by the false contour of the moving image is improved by using the object.

Further, in the invention disclosed in Japanese Unexamined Patent Publication No. 10-161586 entitled "Driving method and driving circuit of display device", a sub-field which is included in a field period and has the same luminance is turned on. By replacing a field with a subfield that is not illuminated, the problem caused by the false contour of the moving image is improved.

[0008]

However, in the above-mentioned prior art, although there is almost no harm in terms of circuit cost and scanning drive, there is still room for improvement for high-quality images.

In order to solve such a problem, the present invention detects a screen in which a false contour of a moving image is likely to occur from a change in bits of data of a video signal, reduces the number of gradations of the video signal, and sets a lighting period.・ By controlling the writing period,
It is an object of the present invention to provide a display device and a display method capable of improving a defect due to a false contour of a moving image.

[0010]

According to the present invention, a lighting time of one field period corresponding to one frame is divided into a plurality of sub-on times based on the luminance of a pixel, and a gradation is obtained. Detecting means for comparing corresponding pixels between two consecutive frames in a display device for displaying, and detecting the number of pixels whose one most significant bit and the second most significant bit are different from those of the other; When the number of pixels is larger than a predetermined threshold, a new on-time pattern in which the number of sub-on times corresponding to the most significant bit in the predetermined on-time pattern of a plurality of sub-on times is increased. A false contour preventing display device for a moving image, comprising: a setting means for setting.

In the above-mentioned moving image false contour prevention display device, when the number of pixels is larger than a predetermined threshold value, the setting means sets the nth most significant bit (n) from the most significant bit to the new on-time pattern. May be further provided with a means for setting a new on-time pattern in which the number of sub-on times corresponding to (a natural number of 2 or more) is increased.

Further, in the above-mentioned moving image false contour prevention display device, all the sub-on times in the new on-time pattern from the least significant bit to a bit higher by several minutes than the sub-on time increased by the setting means are deleted. It is possible to further include a deletion unit for setting a new on-time pattern.

Further, the above-mentioned moving image false contour prevention display device has a pattern table storing a plurality of sub-on time configurations corresponding to the on-time patterns.
When the number of pixels is larger than a predetermined threshold, a predetermined on-time pattern including a plurality of sub-on times is referred to as a new on-time pattern including a predetermined sub-on time configuration selected with reference to a pattern table. It can be characterized by setting.

[0014] In addition, the moving image false contour prevention display device may further include an order changing means for changing an arrangement order of a plurality of sub-on times included in the new on-time pattern.

Further, the moving image false contour prevention display device may further include a display means for displaying the latter frame of the two frames by using a new on-time pattern.

According to the present invention, there is provided a display for performing gradation display by dividing a lighting time of one field period corresponding to one frame into a plurality of sub-on times based on pixel luminance. A detecting step of comparing corresponding pixels between two consecutive frames to detect a number of pixels whose one most significant bit and the second most significant bit are different from those of the other; A setting step of setting a new on-time pattern in which the number of sub-on times corresponding to the most significant bit in a predetermined on-time pattern including a plurality of sub-on times is increased when the value is larger than a predetermined threshold value And a moving image false contour preventing and displaying method.

In the above moving image false contour prevention display method,
The setting step includes, when the number of pixels is larger than a predetermined threshold value, the sub-on time corresponding to the n-th upper bit (n is a natural number of 2 or more) from the most significant bit in the new on-time pattern. It may further comprise the step of setting a new on-time pattern with an increased number.

Further, in the above-mentioned moving image false contour prevention display method, all sub-on times corresponding to bits from the least significant bit to a bit higher by several minutes than the sub-on time increased by the setting means in the new on-time pattern are deleted. It is also possible to further include a deletion step of setting a new on-time pattern.

Further, in the above-mentioned moving image false contour prevention and display method, there is further provided a preliminary setting step of presetting a plurality of sub-on-time configurations corresponding to the on-time patterns,
In the setting step, when the number of pixels is larger than a predetermined threshold, a predetermined on-time pattern including a plurality of sub-on times is selected with reference to the plurality of sub-on time configurations set in the preliminary setting step. Setting a new on-time pattern having a predetermined sub-on-time configuration.

In addition, the above-mentioned moving image false contour prevention and display method may further include an order changing step of changing an arrangement order of a plurality of sub-on times included in the new on-time pattern.

In addition, the above-described moving image false contour prevention display method may further include a display step of displaying the latter frame of the two frames by using a new on-time pattern.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A display device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a display device according to the present invention. Note that the display device of the present invention can be applied to a plasma display or a display such as a ferroelectric liquid crystal that performs gradation display in a subfield.

The display device of the present invention comprises a data input unit 10, a control unit 20, and a display unit 30. The data input unit 10 acquires a video signal or video data and transmits the video signal or video data to the control unit 20. The data input unit 10 includes an antenna and a device capable of reading video data recorded in advance by a recording medium.

The control unit 20 controls the display unit 30 in accordance with the video data input from the data input unit 10.
The control unit 20 includes a frame storage unit 21, an operation unit 22, a result comparison unit 23, a subfield expansion change unit 24, and a drive unit 2.
Consists of five.

The data input unit 1 is stored in the frame storage unit 21.
The temporally continuous video data input from 0 is recorded for one frame. The detection unit 22 compares the video data input from the data input unit 10 with the video data stored in the frame storage unit 21 for each pixel, and determines that the video data of a certain pixel is MSB (Most Significant Bit: maximum value). Bit) to MSB-1 and MSB-1
When the signal has changed from to MSB, a signal indicating the change is output to the result comparison unit 23. Here, MSB-k (k is a natural number) indicates a bit k digits smaller than the MSB.

The result comparing section 23 has a threshold value table 231 for storing a predetermined threshold value. Also,
The number of times of output of the signal output from the detection unit 22 is counted, and when one frame is counted, the count is compared with a threshold stored in the threshold table 231. The result of the comparison is notified to the subfield expansion change unit 24.

Upon receiving the notification from the result comparing unit 23, the subfield expansion changing unit 24 changes the expansion of the subfield included in one field cycle. The driving unit 25 includes:
It has a video data storage unit 251 and a panel control unit 253. The video data storage unit 251 has a video data recording table 252, and writes video data to be displayed on the display unit 30 to the video data recording table 252. The panel control means 253 has a panel control pulse generation circuit 254, and controls the lighting of the panel using the control pulse generated by the panel control pulse generation circuit 254. At this time, the display unit 30 is controlled based on the video data stored in the video data recording table 252. If the subfield expansion changing unit 24 has changed the expansion of the subfield, it receives the changed information and controls the lighting of the panel in accordance with the information.

Here, with respect to the above-mentioned video data, when the count number is larger than the threshold value from the result comparing section 23, the video data input from the data input section 10 is changed by the subfield expansion changing section 24 to 1 The data is changed to the one adapted to the gradation expressed by the field period, and is written in the video data recording table 252. At this time,
The drive unit 25 controls the display unit 30 using the one-field cycle changed by the subfield expansion change unit 24.

When the count number of the video data is smaller than the threshold value from the result comparing unit 23, the video data input from the data input unit 10 is written to the video data recording table 252 as it is.

The display unit 30 displays the video data recording table 2
Display is performed based on the video data stored in 52. The display means is controlled by the drive unit 25. The display unit 30 includes a panel capable of displaying digital data. Here, the lighting time of one field period used in the embodiment of the invention corresponds to one field cycle, the sub-on time corresponds to a subframe, and the on-time pattern corresponds to the arrangement of subframes of one field cycle.

Next, the operation of the display device of the present invention will be described below. FIG. 2 is a flowchart showing the operation of the display device of the present invention.

The video signal or the video data input from the data input unit 10 is sent to the control unit 20, and is stored in the frame storage unit 21.
One frame is stored (step A1).

In the detection unit 22, the frame storage unit 21
Is compared with the video data of the next one frame input from the data input unit 10 for each pixel (step A2). At this time, the video data corresponding to each pixel is MSB between the above two frames.
From MSB-1 to MSB-1 and from MSB-1 to M
Each time it changes to SB, it outputs a signal “H” to the result comparison unit 23.

The number of times of output of the signal "H" output from the detection unit 22 is counted by the result comparison unit 23, and when the comparison of the two frames is completed, a comparison is made with a predetermined threshold value (step). A3).

When the counted number is larger than the threshold value (step A3), it is determined that a screen in which the false contour of the moving image is likely to be detected is detected, and the subfield expansion changing unit 24 is requested to change the expansion of the subfield.

The subfield expansion changing unit 24 changes the expansion of the subfield included in one field cycle in response to the request from the result comparison unit 23 (step A).
4). At this time, the subfield expansion changing unit 24 increases and distributes the number of expansion of the subfields having a large weight. This increases the number of subfields.
However, one field period has a predetermined time and cannot include more than a predetermined amount of subfields. Therefore, instead of including a subfield in which the number of expansions is increased in one field cycle, LSB (Least Si
The number of subfields included in one field period is adjusted by reducing the number of subfields corresponding to lower digits in order from gnificant bit (minimum value bit).
As a result, the number of gradations included in one field period is reduced.

Next, the video data is adapted to the one-field cycle changed by the subfield expansion changing unit 24 (step A5), and the video data is written to the video data recording table 252 of the drive unit 25 (step A).
6). Specifically, video data excluding data corresponding to the reduced number of gradations, that is, data obtained by deleting lower-order bits of the original video data is stored.

When the counted number is smaller than the threshold value (step A3), it is determined that a screen in which the false contour of the moving image is unlikely to be detected is detected, and the original video data is stored in the video data storage table 252 of the drive unit 25. Write (Step A
6).

Next, display on the display unit 30 is controlled in accordance with the video data written in step A6 (step A7). Here, the operation of changing the expansion of the subfield in the subfield expansion changing unit 24 will be described with reference to FIGS.

FIGS. 3 and 4 are examples showing the state of a plurality of subfields developed in one field cycle.
FIG. 3 is a diagram showing a state of a plurality of subfields when the subfield has a predetermined number of gradations. FIG. 4 is a diagram illustrating a state of a plurality of subfields when the number of gradations is reduced in the subfield expansion changing unit 24.

As shown in FIG. 3, the gradation expression in the display device of the present invention is achieved by developing a lighting period corresponding to the luminance (weighting) of the video signal in the display unit 30 during one field period. Is going. Before each lighting period, a period for writing a lighting location on panel 10 is required.
This writing period is constant. Here, each subfield includes each lighting period and a corresponding writing period, and relates to lighting with a predetermined luminance.

In FIG. 3, LS is generated during one field period.
Subfields corresponding to B to MSB are expanded. In FIG. 3, the subfields corresponding to MSB and MSB-1 are each divided into two subfields. However, if the subfields corresponding to LSB to MSB are developed in one field period, the subfields shown in FIG. However, the present invention is not limited to the subfield expansion shown in FIG.
The arrangement of the subfields shown in FIG. 3 is not particularly limited, and can be set arbitrarily.

In FIG. 4, LS is generated during one field period.
Subfields corresponding to B + 2 to MSB are expanded. In FIG. 4, the subfields corresponding to MSB and MSB-1 are each divided into three subfields. The arrangement of the subfields shown in FIG. 4 is not particularly limited, and can be set arbitrarily.

With reference to FIGS. 3 and 4, a description will be given of a change in subfield development in one field cycle. In the normal gradation expression, as shown in FIG. 3, subfields corresponding to LSB to MSB are developed in one field period, and are used by using them. Here, in the result comparison unit 23, when the count number of the signal output from the detection unit 22 is larger than a predetermined threshold value, it is determined that a screen in which a false contour of a moving image is likely to be detected has been detected. In that case,
In order to prevent the generation of the false contour of the moving image, the one-field period shown in FIG. This one-field cycle is obtained by increasing and dispersing the number of expanded subfields with a larger weight than that shown in FIG. Therefore, the false contour of the moving image is reduced.

FIG. 5 is a block diagram showing an example of the display device according to the present invention together with the flow of a video signal.

The display device shown in FIG.
1, arithmetic unit 42, counter 43, comparator 44, gradation conversion 45, memory 46 for each subfield, data driver 4
7. Panel control pulse generation circuit 48, scan driver 49
And a panel 50.

The frame memory 41, the arithmetic unit 42, the counter 43, the comparator 44, the gradation conversion 45, the subfield memory 46, the data driver 47, the panel control pulse generating circuit 48 and the scanning driver 49 are controlled by the control shown in FIG. This corresponds to the unit 20. Further, the panel 50 corresponds to the display unit 30 shown in FIG.

The control unit 20 will be described in detail. The frame memory 41 is stored in the frame storage unit 21 shown in FIG.
Corresponding to The computing unit 42 corresponds to the detection unit 22 shown in FIG. The counter 43 and the comparator 44 correspond to the result comparing unit 23 shown in FIG. The gradation conversion 45 corresponds to the subfield expansion changing unit 24 shown in FIG. The sub-field memory 46, data driver 47, panel control pulse generation circuit 48, and scan driver 49 correspond to the drive unit 25 shown in FIG.

The operation of the display device shown in FIG. 5 will be described below. The frame memory 41 stores a temporally continuous video signal (data) for one frame. The arithmetic unit 42 calculates the data of the video signal and the data of the video signal delayed by one frame from the frame memory 1. In the calculation, when the video data of an arbitrary pixel changes, for example, from MSB (most significant bit) to MSB-1 (most significant bit-1) during one frame, or from MSB-1 to MSB
"H" is output to the counter 43 only when it changes to B.

Specifically, the operation of the arithmetic unit 42 will be described below. The arithmetic unit 42 performs an arithmetic operation on the video data of each pixel using only the MSB digit and the MSB-1 digit. Only when the sum is "11" and the absolute value of the difference is "01" for the video data in each pixel, the counter 43 is set to "H".
Is output.

The counter 43 counts "H" output from the arithmetic unit 42. Only when the output (count value) from the counter 43 exceeds a predetermined threshold value, the comparator 44 outputs a detection signal indicating that a screen in which a false contour of a moving image is likely to be detected has been detected.

The gradation conversion 45 receives the video data and reduces the number of gradations of the video data in response to a detection signal from the comparator 44 (gradation conversion). Specifically, FIG.
According to the operation shown in FIG. Further, the gradation conversion 45
When a screen in which a false contour of a moving image is likely to be generated is not detected, that is, when there is no detection signal from the comparator 44, the operation of reducing the number of tones for received video data is not performed.

The memory 46 for each subfield stores the video data output from the gradation conversion 45 described above. The data driver 47 controls the display operation of the panel 50 based on the video data stored in the memory 46 for each subfield.

The panel control pulse generation circuit 48 transmits a drive control signal for controlling the lighting period and the writing period to the scan driver 49 based on the detection signal from the comparator 44. Here, the drive control signal is determined based on information indicating one field cycle that has undergone gradation conversion by the gradation conversion 45. The scan driver 49 controls the lighting operation of the panel 50 based on the drive control signal transmitted from the panel control pulse generation circuit 48.

When a screen in which a false contour of a moving image is likely to be detected is detected, the panel control pulse
The lighting period and the writing period are controlled on the basis of the signal from the control unit 4. Therefore, the number of expanded subfields having a large weight included in one field period is increased and dispersed.
At this time, the number of sub-fields included in one field cycle increases, so that the number of times of writing increases, and the sum of writing and lighting time included in one field cycle increases. However, the gradation conversion 45 reduces the number of gradations for one field cycle based on the signal from the comparator 44, so that the sum of the writing and the lighting time is included in one field cycle.

FIG. 6 is a block diagram showing a modification of the display device according to the present invention. The display device of the present invention includes a data input unit 10, a control unit 20, and a display unit 30.

The control unit 20 controls the display unit 30 according to the video data input from the data input unit 10. The control unit 20 includes a frame storage unit 21, an arithmetic unit 2,
2. Result comparison unit 23, subfield expansion change unit 24,
It comprises a drive unit 25.

The difference from the display device of the present invention shown in FIG. 1 is that the subfield expansion / change section 24 has a field table 241. Accordingly, only the configuration and operation of the subfield expansion changing unit 24 are different.

The different configuration and operation will be described below. First, the field table 241 previously stores a plurality of different data indicating one field cycle composed of a plurality of subfields. The plurality of subfields developed corresponding to the stored data are configured to fit within the time indicated by one field cycle.

Upon receiving the notification from the result comparing unit 23, the subfield expansion changing unit 24
One of the data stored in the first data is obtained, and the modified one comprising the configuration of a plurality of subfields based on the data is obtained.
Get the field period. A plurality of subfields developed in the changed one-field cycle are compared with a plurality of subfields developed in the one-field cycle before the change. As a result of the comparison, when the number of expanded subfields with a large weight is small or equal, data is obtained again from the field table 241 to change the configuration of a plurality of subfields included in one field cycle, and again before the change. Is compared with one field period. As a result of the comparison, when the number of developed subfields with a large weight is large, one field period including the configuration of the changed plurality of subfields is obtained as the developed subfield.

Further, in the display device shown in FIG.
The threshold table 231 has a configuration having a plurality of thresholds, and accordingly, the subfield table 241
Are different from each other, and the operation example in the case where the operation of the result comparing unit 23 and the operation of the subfield expansion changing unit 24 are different is shown below.

First, the threshold value table 231 has a plurality of threshold values. The result comparing unit 23 compares the number of output times of the signal output from the detecting unit 22 for each threshold value,
The comparison data indicating the comparison result with respect to each threshold is output to the subfield expansion change unit 24. The subfield expansion change unit 24 acquires the field configuration corresponding to the comparison data from the subfield table 241.
Here, the field configuration includes a configuration of a plurality of subfields included in one field period, and the subfield table 241 includes a threshold table 231.
Configuration data indicating the field configuration corresponding to the comparison result in the result comparison unit 23 with respect to each threshold value determined by the above is stored.

Here, the subfield expansion change unit 24
Can hold the comparison data transmitted from the result comparison unit 23 for a predetermined period, and change the field configuration based on the held comparison data. At this time, the subfield table 241 stores configuration data indicating the field configuration corresponding to the held comparison data.

The subfield table 241 stores configuration data indicating a plurality of field configurations corresponding to each comparison result in the result comparison unit 23 with respect to each threshold value determined in the threshold value table 231. When this is done, the following operations are possible. Compare the changed field configuration with the field configuration before the change. In the comparison result, when the expansion number of the subfield having a large weight is small or equal, the data corresponding to the comparison result is obtained from the field table 241 again, the field configuration is changed, and the field configuration before the change is compared again. I do. As a result of the comparison, when the number of expanded subfields with a large weight is large, the configuration of a plurality of subfields with respect to the changed field configuration is acquired as the expanded subfield.

In the above-described operation, a configuration is possible in which a CPU (not shown) executes the operation based on an algorithm corresponding to the operation.

Here, the lighting time of one field period used in the embodiment of the invention is one field cycle, the sub-on time is a sub-frame, the on-time pattern is the arrangement of sub-frames of one field cycle, The table corresponds to a threshold table.

As described above, in the embodiment of the present invention, the display device or the display device which develops the gradation expression into subfields according to the weight of the video data and controls the number of lightings per unit time by combining the subfields. In the method, a screen in which a false contour of a moving image is likely to be generated is detected from a change in a predetermined bit of video data, the number of gradations when displaying the relevant video data is reduced, and the lighting period and the writing period are controlled. Therefore, a false contour of a moving image can be reduced on a screen where a moving image outline is likely to occur.

When a screen in which a false contour of a moving image is likely to be detected is not detected, the operation of reducing the number of gradations is not performed. Therefore, the number of gradations can be ensured on a screen other than a screen where a false contour of a moving image is likely to occur. Furthermore, on a screen in which a false contour of a moving image is likely to occur, the number of gradations is reduced, so that a phenomenon in which the color of the screen changes due to the false contour of the moving image is reduced, so that the overall image quality can be improved. it can.

[0070]

The display device and the display method according to the present invention are as follows.
The problem caused by the false contour of the moving image can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a display device according to the present invention.

FIG. 2 is a flowchart showing the operation of the display device of the present invention.

FIG. 3 is a diagram showing a state of a plurality of subfields developed in one field period when the number of gradations is predetermined.

FIG. 4 is a diagram illustrating a state of a plurality of subfields developed in one field cycle when the number of gradations is reduced in a subfield development changing unit.

FIG. 5 is a block diagram showing an example of a display device according to the present invention together with a flow of a video signal.

FIG. 6 is a block diagram showing a modification of the display device according to the present invention.

[Description of Signs] 10 Data input unit 20 Control unit 21 Frame storage unit 22 Detection unit 23 Result comparison unit 231 Threshold table 24 Subfield expansion change unit 241 Field table 25 Drive unit 251 Write unit 252 Video data record table 253 Control means 254 Panel control pulse generation circuit 41 Frame memory 42 Computing unit 43 Counter 44 Comparator 45 Gradation conversion 46 Subfield memory 47 Data driver 48 Panel control pulse generation circuit 49 Scan driver 50 Panel

Claims (12)

[Claims] 1. A display device for performing gradation display by dividing a lighting time of one field period corresponding to one frame into a plurality of sub-on times based on luminance of a pixel. In comparison, a detecting means for detecting the number of the pixels whose one most significant bit and the second most significant bit are different from those of the other, when the number of the pixels is larger than a predetermined threshold value, Setting means for setting a new on-time pattern in which the number of sub-on times corresponding to the most significant bits is increased, in a predetermined on-time pattern comprising a plurality of sub-on times; apparatus. 2. The method according to claim 1, wherein when the number of pixels is larger than a predetermined threshold value, the setting means sets an n-th upper bit (n is 2 or more) from the most significant bit in the new on-time pattern. 2. The moving image false contour prevention display device according to claim 1, further comprising: means for setting a new on-time pattern in which the number of sub-on times corresponding to (a natural number of) is increased. 3. A new on-time pattern in which all sub-on times corresponding to bits from the least significant bit to a bit higher by several minutes than the sub-on time increased by the setting means in the new on-time pattern are deleted. The moving image false contour prevention display device according to claim 1 or 2, further comprising a deletion unit for setting. 4. A pattern table storing a plurality of sub-on-time configurations corresponding to on-time patterns, wherein the setting unit is configured to: when the number of pixels is larger than a predetermined threshold,
The method according to claim 1, wherein a predetermined on-time pattern including a plurality of sub-on times is set as a new on-time pattern having a predetermined sub-on time configuration selected with reference to the pattern table. Video false contour prevention display device. 5. The moving image false contour prevention display device according to claim 1, further comprising an order changing unit that changes an arrangement order of the plurality of sub-on times included in the new on-time pattern. 6. Using the new on-time pattern,
The moving image false contour prevention display device according to any one of claims 1 to 5, further comprising a display unit that displays a latter one of the two frames. 7. A display method for performing gradation display by dividing a lighting time of one field period corresponding to one frame into a plurality of sub-on times based on pixel brightness, wherein a corresponding pixel between two consecutive frames is displayed. Comparing the number of pixels whose one most significant bit and the second most significant bit are different from those of the other, and when the number of pixels is greater than a predetermined threshold, A setting step of setting a new on-time pattern in which the number of sub-on times corresponding to the most significant bits in a predetermined on-time pattern including a plurality of sub-on times is increased; . 8. The method according to claim 1, wherein the setting step comprises: when the number of pixels is larger than a predetermined threshold, the n-th upper bit (n is 2 or more) from the most significant bit in the new on-time pattern. The false false contour prevention display method for a moving image according to claim 7, further comprising: setting a new on-time pattern in which the number of sub-on times corresponding to (a natural number of) is increased. 9. A new on-time pattern in which all sub-on times corresponding to bits from the least significant bit to a bit higher by several minutes than the sub-on time increased by the setting means in the new on-time pattern are deleted. The moving image false contour prevention display method according to claim 7 or 8, further comprising a setting deletion step. 10. A preliminary setting step of presetting a plurality of sub-on time configurations corresponding to an on-time pattern, wherein the setting step comprises: when the number of pixels is larger than a predetermined threshold value,
A predetermined on-time pattern including a plurality of sub-on times is set with reference to the plurality of sub-on time configurations set in the preliminary setting step, and a new on-time pattern including a predetermined sub-on time configuration selected is set. The moving image false contour prevention display method according to claim 7, comprising a step. 11. The moving image false contour prevention display method according to claim 7, further comprising an order changing step of changing an arrangement order of the plurality of sub-on times included in the new on-time pattern. 12. The moving image false contour prevention display method according to claim 7, further comprising a display step of displaying a latter one of the two frames by using the new on-time pattern.