JP2000172225A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend usage range by realizing the best display. SOLUTION: In this display device for performing gray shades display by divingding three or more subfields sf1 to sf16 constituting one field into one or more subfield groups sfg1 to sfg3 and assiging preparation periods for intializing displays to beginnings of the subfield groups sfg1 to sfg3, first and second display modes are provided. The device is provided with a control means for applying first field configurations f11, f12 to attentional fields being display objects in the first mode and for applying second field configurations f11, f22 whose each maximum value of weight is different from that of the first field configuration to the attentional fields in the second display mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for reproducing halftones by intra-field modulation, and relates to an AC P-type display device.
It is suitable for display by a DP (Plasma Display Panel).

[0002] PDPs have both high speed and resolution that can be used for both televisions and computer monitors. It is desired to reduce false contours for moving image display, and to increase the number of gradations for still image display.

[0003]

2. Description of the Related Art The luminance of a display in a PDP depends on the number of discharges per unit time. Therefore, reproduction of the halftone is performed by appropriately setting the number of discharges in one field for each cell in accordance with the gradation level. Color display is a type of gradation display, and the display color is determined by the combination of the luminance of the three primary colors.

[0004] A "field" in this specification is a unit image for displaying a time-series image. That is, in the case of a television, it means each field of an interlaced frame, and in the case of a non-interlaced format represented by a computer output (which can be regarded as a one-to-one interlaced format), it means the frame itself.

[0005] As a gradation display method of a PDP, a method is widely known in which one field is composed of a plurality of sub-fields weighted with luminance, and the total number of discharges in one field is set by a combination of lighting on / off in units of sub-fields. (JP-A-4-195188). “Brightness weight”
Is a numerical value (usually represented by an integer whose minimum value is 1) for determining which subfield is selected as a lighting target according to the gradation of the input image. Generally, the weight is 2 ⁿ (n = 0, 1, 2, 3) for each subfield.
..) Is performed. For example, if the number of subfields is 8, display of 256 gradations with gradation levels of “0” to “255” is possible.

[0006] Binary weighting has no redundancy in the weights and is suitable for multiple gradations. However, in order to make the gradation width (luminance difference for one gradation) uniform over the entire gradation range, addressing must be performed for each subfield. Further, in at least one subfield for each field, a reset process (preparation for addressing) for equalizing the charged state of the entire screen must be performed prior to addressing. If the reset process is omitted, the discharge condition is different between the cell in which the wall charges remain (previous lighting cell) and the other cell (previous non-lighting cell), and it is difficult to reliably perform addressing.
Normally, reset processing is performed for each subfield in order to increase the reliability of addressing.

However, since the reset processing and the addressing involve discharge, it is desirable that the number of these operations be smaller from the viewpoint of contrast and power consumption. In particular, in a high-definition PDP, the burden on circuit components for addressing is large, and therefore, it is desired to reduce the number of times of addressing from the viewpoint of measures against heat generation.

In view of the above, a driving method has conventionally been proposed in which a predetermined number of subfields are divided into a plurality of subfield groups, and reset processing is performed once for each subfield group (Japanese Patent No. 2639311). The weights of the subfields belonging to each subfield group are made equal, and the weight of each subfield is a value obtained by adding the minimum value of the weight to the sum of the smaller weights. Thus, the gradation width can be made uniform over the entire gradation range.

The present applicant has proposed a display device for switching the field configuration in accordance with the luminance distribution of the field to perform gradation display as Japanese Patent Application No. 10-202481.
According to the proposed device, when displaying a dark field as a whole, the problem that the background portion occupying the majority of the screen is slightly lit up by the discharge for the reset processing and the addressing and appears to be lifted and appears. can do.

[0010]

As described above, in a gray scale display in which a field is composed of a plurality of subfields, even if the total number of subfields per field and the number of subfield groups are fixed, the number of subfield groups is small. A plurality of types of field configurations can be obtained depending on the number of subfields to be combined and the selection of the luminance weight of each subfield.

Heretofore, one field configuration has been set for each category classified by luminance distribution so as to realize the best display for a specific application (for example, television display). Then, one field configuration is uniformly applied to each type of field classified by the luminance distribution.
For this reason, there has been a problem that the best display may not be realized when used for an application other than the specific application.
For example, when setting the field configuration, if the maximum value of the weight is selected to be small in order to reduce false contours in moving image display, the number of gradations will decrease. Therefore, this field configuration is suitable for television, but is not suitable for computer graphics in terms of the number of display colors.

SUMMARY OF THE INVENTION An object of the present invention is to expand a range of applications in which the best display can be realized.

[0013]

According to the present invention, a function is provided for switching the field configuration in accordance with the characteristics of an input image signal. For example, gradation display is performed by applying different field configurations depending on whether the input image is a moving image or a still image. It is also possible to divide the characteristics into three or more classes and to switch between three or more field configurations.

According to the first aspect of the present invention, one field is composed of three or more sub-fields weighted with luminance, and an addressing period for setting the necessity of lighting of each cell and a lighting maintenance for maintaining a lighting state. A period is assigned to each subfield, the set of subfields for one field is divided into one or more subfield groups, and a preparation period for initializing the display is assigned to the beginning of the subfield group to perform gradation display. A display device for performing a gradation display by applying a first field configuration to a target field to be displayed in the first display mode, wherein the first and second display modes are provided. In the second display mode, gradation display is performed by applying a second field configuration having a different maximum weight from the first field configuration to the field of interest. .

In a display device according to a second aspect of the present invention, a plurality of field configurations having different numbers of subfield groups are provided for each of the first and second display modes, and at least one field configuration including the field of interest is provided. A luminance determination unit that calculates a luminance distribution of the field and determines the calculated luminance distribution according to a setting condition; and, according to a result of the determination of the luminance distribution, the display mode corresponding to the display mode selected for the field of interest. Control means for selecting one of the plurality of field configurations and applying the selected one to the gradation display of the field of interest;
It is provided with.

A display device according to a third aspect of the present invention has a selector for selecting one of a plurality of input signals as a display target, and sets a display mode in conjunction with the selection by the selector.

A display device according to a fourth aspect of the present invention has an operation means for designating a display mode, and sets the display mode according to a state of the operation means.

[0018]

FIG. 1 is a configuration diagram of a plasma display device 100 according to the present invention.

The plasma display device 100 is composed of an AC type PDP 1 which is a matrix type color display device, and a drive unit 80 for selectively lighting a number of cells C constituting a screen ES. It is used as a wall-mounted television receiver, a computer system monitor, and the like.

The PDP 1 has a pair of first and second main electrodes X and Y arranged in parallel.
3 where Y intersects with an address electrode A as a third electrode
An electrode surface discharge structure is adopted. The main electrodes X and Y extend in the row direction (horizontal direction) of the screen, and one main electrode Y is used as a scan electrode for selecting cells on a row basis at the time of addressing. Address electrode A is in column direction (vertical direction)
And is used as a data electrode for selecting cells on a column basis. The area where the main electrode group and the address electrode group intersect is the screen ES.

The drive unit 80 includes a controller 81,
In addition to the basic components of the frame memory 82, the data processing circuit 83, the subfield memory 84, the power supply circuit 85, the X driver 86, the Y driver 87, and the address driver 88, five components according to the present invention (subfield selection A circuit 91, a luminance distribution determination circuit 92, a similarity determination circuit 93, a selector 94, and an operation unit 95). An input signal (image data) D indicating the luminance level (gradation level) of each color of R, G, and B of each pixel from an external device such as a TV tuner computer is input to the drive unit 80.
1 and D2 are input together with various synchronization signals. The operation unit 95 is not limited to one operated by the user of the plasma display device 100, and may be one for setting before shipment from the factory.

The selector 94 selects one of the input signals D1 and D2 as the field data Df to be displayed according to the input selection signal S1 from the operation unit 95. The field data Df is once stored in the frame memory 82 and then sent to the data processing circuit 83. The data processing circuit 83 is data conversion means for setting a combination of subfields to be turned on, and outputs subfield data Dsf corresponding to the gradation level indicated by the field data Df. The subfield data Dsf is stored in the subfield memory 84. Subfield data Dsf
The value of each bit is information indicating the necessity of lighting of the cell in the subfield, more specifically, the necessity of address discharge. The X driver circuit 86 applies a drive voltage to the main electrode X, and the Y driver circuit 87 applies a drive voltage to the main electrode Y. The address driver 88 controls the subfield data D
A drive voltage is applied to the address electrode A according to sf. A predetermined power is supplied from the power supply circuit 85 to these driver circuits.

In this embodiment, the field data Df is input to the similarity determination circuit 93 and the luminance distribution determination circuit 92 in parallel with the storage in the frame memory 82.

The similarity determination circuit 93 determines whether or not the j-th (arbitrary integer) field is similar to the previous field. When the input is in a non-interlaced format, all the input fields are sequentially focused, and the similarity between the focused field and the immediately preceding field is determined. In the case of the interlace format, one field (here, an odd field) of all input frames is sequentially focused, and the noted odd field and the immediately preceding odd field (the field of interest is an even field) In this case, the similarity is determined. Normally, the luminance distributions of the odd and even fields constituting one frame are almost the same, so that there is no problem even if only one field is focused on. The determination data D93 indicating the result of the similarity determination is input to the luminance distribution determination circuit 92.

The luminance distribution determining circuit 92 includes a histogramgram for counting pixels of each luminance level for each of the R, G, and B planes, and determines luminance distribution data (luminance histogram) of each plane for each field in a manner described later. I do. that time,
The judgment data D93 is referred to. Data D91 indicating the display mode is input from the subfield selection circuit 91 to the luminance distribution determination circuit 92. Data D92 indicating a combination of the data D91 and the determination result of the luminance distribution data is output from the luminance distribution determination circuit 92 to the controller 81. In the luminance distribution determination circuit 92, the luminance distribution is calculated for only a single field of interest, and also for a plurality of (for example, five) fields including the field of interest.

An input selection signal S1 and a mode switching signal S2 are input from the operation unit 95 to the subfield selection circuit 91. The display device 100 has two display modes, a still image mode and a moving image mode. Switching between these modes is linked to selection of an input signal by the selector 94, and is automatically performed in response to a change in the state of the input selection signal S1. When the input signal D1, which is a video signal from a TV tuner, a video recorder, or the like, is selected, the moving image mode is set as a default mode. On the other hand, when the input signal D2 in which most of the information represented by the computer output is a still image is selected,
The still image mode is set as the default mode.
However, when the user performs a mode switching operation, the mode switching signal S2 becomes active, and the other mode is selected instead of the default mode. Mode switching is useful when playing back moving images on a computer or still playback on a video recorder. It should be noted that the mode designating operation may be switched or not switched.
There is a configuration in which three options are provided, and a configuration in which three options of a still image mode / moving image mode / automatic (manual setting is turned off) are provided.

The controller 81 outputs a switching signal Ssf for instructing the application of one field configuration corresponding to the value of the data D92 from a plurality of (five in this example) field configurations stored in advance in the data processing circuit. 83.
Data processing circuit 83 converts field data Df into subfield data Dsf according to switching signal Ssf.

FIG. 2 is a schematic diagram of the field division.

In order to reproduce gradation by binary lighting control, each field f (subscript indicates an input order) of a time series as an input image is divided into 16 subfields sf1 and sf.
2, sf3, sf4, sf5, sf6, sf7, sf
8, sf9, sf10, sf11, sf12, sf1
3, sf14, sf15, and sf16. In other words, the corresponding field f in each field period Tf is replaced with a set of 16 subfields sf1 to sf16 and displayed. Then, in order to perform lighting control on a cell basis, an addressing period and a sustain period (display period) are assigned to each of the subfields sf1 to sf16.

The number of subfields is not limited to 16. From the viewpoint of gradation, it is desirable to increase the number of subfields as much as possible so that the product of the time required for one addressing and the number of subfields does not exceed the field period Tf.

FIG. 3 is a diagram showing options of the field configuration.

The three field configurations f11, f12, and f13 shown in FIG. 3A are options in the still image mode, and the three field configurations f21, f22, and f23 shown in FIG. It is an option in the mode. Since the field configuration f23 is the same as the field configuration f13, a total of five options are provided.

In the field structure f11, the subfield sf1 is used to reduce the number of times of addressing.
To sf16 are three subfield groups sfg1, sfg
2, sfg3. A set of five subfields sf1 to sf5 from the head of the display order to the fifth is set as a first subfield group sfg1, and five subfields sf6 to sf6 from the sixth to the tenth are displayed.
A set of f10 is a second subfield group sfg2, and a set of the remaining eleventh to sixteenth subfields sf11 to sf16 is a third subfield group sfg3. Each subfield group s
A preparation period for initializing the display is assigned to fg1 to sfg3. First subfield group sfg1
, The luminance weight of all subfields belonging to the second subfield group sfg2 is set to “6”, and the luminance weight of all subfields belonging to the second subfield group sfg2 is set to “6”.
The luminance weight of all the subfields belonging to the third subfield group sfg3 is set to “36”. Here, the second and third subfield groups sfg2, sfg
The weight of each subfield in 3 is an integer multiple of the minimum weight ("1") and is a value obtained by adding 1 to the sum of the smaller weights. That is, 6 = 1 × 5 + 1 and 36 = 1 × 5 + 6 × 5 + 1. According to this weighting, it is possible to realize a display of 252 gradations having a uniform gradation width of gradation levels “0” to “251” by combining the presence or absence of lighting of the subfield. Therefore, the number of displayable colors in the case of applying this field configuration f11 is 252 ^3.

Each subfield group sfg1 to sfg
In g3, all the weights do not necessarily have to be the same, and can be appropriately selected. For example, one subfield sf1 of the third subfield group sfg3
When the weight of No. 3 is set to “35” and a luminance of weight “36” is obtained, the subfield sf13 of weight “35” and one subfield sf1 of weight “1” may be turned on. Further, it is not necessary to display the weights in order. For example, it is possible to perform optimization such that a subfield having a large weight is arranged in the middle of a field period. In order to prevent false contours in moving image display, it is desirable to avoid extreme continuation of lighting or non-lighting. However, the subfields belonging to each of the subfield groups sfg1 to sfg3 are displayed continuously, and a subfield of another group is not inserted between subfields of a certain group.

FIG. 4 is a time chart showing an example of the lighting control.

The preparation period TR is set for each subfield group sfg.
It is provided at the forefront of 1 to sfg3. In the case of the exemplary erase address driving, in the preparation period TR, a charge forming process of charging all cells with wall charges necessary for maintaining lighting is performed by a driving sequence described below. Therefore,
When the lighting sustaining voltage is applied in a state where the charge forming process is performed, all the cells are turned on. In the addressing period TA assigned to each subfield, wall charges are erased only from cells that do not need lighting. The cell from which the wall charges have been erased does not light even if the lighting sustain voltage is applied until the charge forming process is performed again. In the sustain period TS, a lighting sustaining voltage having an alternating polarity is simultaneously applied to all the cells, and the lighting state of the cell in which the wall charges remain remains.

In each of the subfield groups sfg1 to sfg3, m out of n (5 or 6) subfields
For a cell of a gradation level for lighting (0 ≦ m <n) subfields, wall charges are erased in the (m + 1) th addressing period TA. Elimination of the wall charge is not performed on the cells of the gradation level for lighting the n subfields. For example, in order to reproduce the gradation level “2”, two subfields sf1 and sf1 having a weight of 1
The cells may be turned on during the sustain period TS of f2. In this case, charge is formed on the entire screen in the preparation period TR of the first subfield group sfg1, and charge is erased from the corresponding cell in the addressing period TA of the third subfield sf3. When reproducing the gradation level “1”, the charge is erased in the addressing period TA of the second subfield sf2, and the second to fifth subfields sf2 are erased.
The corresponding cell is not lit during the sustain period TS of 〜sf5.

As described above, each subfield group sfg1
By changing the timing of performing charge erasure in accordance with the gradation level to be reproduced for each sfg3, the number of times of charge formation processing of the entire screen can be reduced to the number of subfield groups, and the number of addressing times is equal to or less than the number of subfield groups. Can be reduced to Since the addressing is of the erasing type, the addressing is unnecessary when the gradation level to be reproduced is the maximum “251”.

Returning to FIG. 3, in the field configuration f12, the subfields sf1 to sf16 are divided into two subfield groups sfg1 and sfg2. A set of eight subfields sf1 to sf8 from the head to the eighth in the display order is a first subfield group sfg.
The set of eight ninth to sixteenth subfields sf9 to sf16 is defined as a second subfield group sfg2. Subfield group sfg1
Is the minimum luminance weight of “1”, and the luminance weight of all subfields belonging to the subfield group sfg2 is “9”. According to this weighting, it is possible to realize a display of 81 gradations having a uniform gradation width of gradation levels “0” to “80”.

The number of colors that can be displayed when this field configuration f12 is applied is 81 ^3. However, since the number of subfield groups is 2, the background luminance is set to the field configuration f11.
Can be reduced to about 67% of the display by

In the field configuration f13, all the subfields sf1 to sf16 are combined into one subfield group sfg1. The luminance weight of all the subfields sf1 to sf16 is the minimum “1”. According to this weighting, the gradation levels “0” to “1”
A display of 17 gradations having a uniform gradation width of "6" can be realized.

[0042] This number of displayable colors when the field configuration f13 is applied is 17 ^3, the number of subfields group is 1, the field constituting the background luminance f11
The display can be reduced to about 33% of the display.

In the field configuration f21 shown in FIG. 3B, the subfields sf1 to sf16 have the same number of three subfield groups sfg1 and sfg1 as the field configuration f11.
fg2 and sfg3. Three subfields sf1 to sf3 from the top to the third in the display order
Is the first subfield group sfg1 and the fourth
To the seventh to seventh subfields sf4 to
A set of sf7 is a second subfield group sfg2, and a set of the remaining nine subfields sf8 to sf16 from the eighth to the sixteenth is a third subfield group sfg3. Each subfield group sfg
A preparation period is assigned to 1 to sfg3.

The luminance weight of all subfields belonging to the first subfield group sfg1 is set to the minimum “1”, and the luminance weight of all subfields belonging to the second subfield group sfg2 is set to “4”. The weight of the luminance of all the subfields belonging to the third subfield group sfg3 is “20”. Similarly to the above configuration, the second and third subfield groups sfg2, sfg
The weight of each subfield in 3 is an integer multiple of the minimum weight and is a value obtained by adding 1 to the sum of the smaller weights. According to this weighting, the gradation levels “0” to
A display of 200 gradations having a uniform gradation width of “199” can be realized.

When this field configuration f21 is applied
Has a maximum weight of "20" and a subfield
Of the weight in the field configuration f11 having the same number of
Extreme of lighting or non-lighting because it is smaller than the large value (36)
The probability of occurrence of a continuation is small, and false contours are unlikely to occur. However
The number of colors that can be displayed in the field configuration f21 is
200^ThreeDisplay in the field configuration f11
Number of possible colors (252 ^Three)Fewer.

In the field configuration f22, the subfields sf1 to sf16 are divided into two subfield groups sfg1 and sfg2 of the same number as the field configuration f21. A set of five subfields sf1 to sf5 from the head of the display order to the fifth is a first subfield group sfg1, and a set of eleven subfields sf6 to sf16 from the sixth to sixteenth Are the second subfield group sfg2. The luminance weight of all the subfields belonging to the subfield group sfg1 is the minimum “1”, and the subfield group sfg1
The luminance weight of all subfields belonging to 2 is “6”
It is. According to this weighting, the gradation levels "0" to "7"
A display of 72 gradations with a uniform gradation width of “1” can be realized.

When the field configuration f22 is applied, since the number of subfield groups is 2, the background luminance can be reduced to about 67% of the display by the field configuration f21. Also, comparing the field configuration 12 and the field configuration 22 with the same number of subfield groups, false contours are less likely to occur when the field configuration f21 is applied. This is because the maximum value of the weight in the field configuration f22 is “6”, which is smaller than the maximum value (9) of the weight in the field configuration f12. However, the number of colors that can be displayed in the field configuration f21 is smaller than the number of colors that can be displayed in the field configuration f11.

FIG. 5 is a voltage waveform diagram showing an example of the driving sequence. Here, the field configuration f11 is represented
Are illustrated, the driving waveforms of the respective periods TR, TA, TS are different from those of the other field configurations f12, f13, f21 to f23.
The same applies to. However, the number of pulses in the sustain period TS is almost proportional to the luminance weight.

In the preparation period TR, a first step of applying a positive voltage pulse Pr to the main electrode X, a positive voltage pulse Prx to the main electrode X, and a negative voltage pulse to the main electrode Y A second step of applying Pry,
Wall charges having a predetermined polarity are formed in the previously lit cell and the previously non-lit cell. In the first step, the address electrode A is biased to a positive potential to prevent unnecessary discharge between the address electrode A and the main electrode X. Subsequent to the second step, a positive voltage pulse Prs is applied to the main electrode Y to increase surface uniformity in all cells in order to improve the uniformity of charging. The charging polarity is reversed by this surface discharge. After that, the potential of the main electrode Y is gradually reduced in order to avoid the loss of charge.

Addressing period T following preparation period TR
In A, a negative scan pulse Py is applied to the main electrode Y to be selected in order to select each line one by one from the top line. Simultaneously with the selection of the line, a positive address pulse Pa is applied to the address electrode A corresponding to the cell to be turned off (the non-lighted cell this time). Address pulse P on selected line
In the cell to which a is applied, an address discharge occurs between the main electrode Y and the address electrode A, and the wall charges of the dielectric layer disappear. At the time of application of the address pulse Pa, positive wall charges exist near the main electrode X, so that the address pulse Pa is canceled by the wall voltage, and no discharge occurs between the main electrode X and the address electrode A. . Such an erasing type addressing is suitable for high-speed operation, since unlike the writing type, it is not necessary to regenerate electric charges.

In the sustain period TS, all address electrodes A are biased to a positive potential in order to prevent unnecessary discharge, and a positive sustain pulse Ps is first applied to all the main electrodes X. After that, a sustain pulse Ps is alternately applied to the main electrode Y and the main electrode X. In the present embodiment, the final sustain pulse Ps is applied to the main electrode Y. Due to the application of the sustain pulse Ps, surface discharge occurs in the cell where the wall charges remain (the currently lit cell) during the addressing period TA.

In the addressing period TA following the sustain period TS, a voltage pulse Pr is applied to the main electrode X and a voltage pulse Prs is applied to the main electrode Y in order to adjust the charge distribution. Then, the potential of the main electrode Y is gradually reduced in the same manner as in the preparation period TR, and then the line-sequential addressing is performed in the same manner as in the first addressing period TA.

Next, a procedure for selecting a field configuration applied to the display of each field f will be described.

FIG. 6 is a diagram for explaining a method of judging a luminance distribution, and FIG. 7 is a diagram showing a selection procedure of a field configuration in a table format.

The luminance distribution determining circuit 92 determines which of the three types of field configurations corresponding to the display mode in which the luminance distribution is set is to be applied, based on the characteristic amount of the luminance distribution. For example, 1 of the luminance histogram
The 00% point, that is, the maximum luminance in the field of interest is set as a feature amount, and the feature amount is compared with threshold values v1, v2, and v3.
The threshold v1 is the maximum luminance that can be expressed by the field configurations f13 and f23 in FIG. 3, and the threshold v2 is the field configuration f2
2, and the threshold v3 is the maximum luminance that can be expressed by the field configuration f12. In the still image mode, the thresholds v1 and v3 are applied.
1, v2 apply.

In the distribution (a) extending from low luminance to high luminance, the feature amount is larger than the threshold values v2 and v3. For the fields of the distribution (a), the field configuration f11 or the field configuration f21 is applied according to the display mode as shown in FIG. In the distribution (b) biased to the low luminance side, the feature amount is a value between the threshold v1 and the threshold v3. The field configuration f12 or the field configuration f22 is applied to the field of the distribution (b). In the distribution (c) biased near the minimum luminance, the feature amount is smaller than the threshold value v1. The field configuration f13 or the field configuration f23 is applied to the field of the distribution (c).

The feature amount is not limited to the 100% point, and the field configuration may be selected based on another point such as the 95% point or the 90% point. Further, the threshold values v1 to v3 may be values close to the maximum value of the luminance that can be expressed by a predetermined field configuration.
However, if the value is set to a value larger than the maximum value, the gradation on the higher luminance side is rounded to the maximum value. Therefore, it is desirable to set the value smaller than the maximum value.

In selecting such a field configuration according to the luminance distribution, the luminance distribution to be determined is switched according to whether or not the field of interest is similar to an adjacent field (this is because the field for which the luminance distribution is to be calculated is changed). It is equivalent to switching). That is, when the degree of similarity is larger than the threshold value and the determination data D93 indicates similarity (when a series of fields is regarded as a video of a continuous scene), based on the luminance distribution calculated for a plurality of fields. The field configuration is selected. On the other hand, when the determination data D93 indicates dissimilarity (when the scene changes greatly), the field configuration is selected based on the luminance distribution calculated only for the field of interest. By changing the selection form of the field configuration according to the result of the similarity determination in this manner, in a continuous scene,
In the case where the feature amount of the image fluctuates near the threshold v1 to v3 for selecting the field configuration, it is possible to avoid flickering of the background luminance by changing the field configuration for each field.

According to the above embodiment, the result of the field similarity determination is reflected in the switching of the field configuration, so that a display with less disturbance can be realized. However, the similarity determination circuit 93 may be omitted, and an optimal field configuration may be selected only according to the result of the luminance distribution determination. The field configuration may be selected according to only the display mode without determining the luminance distribution. Also,
It is not always necessary to select a field configuration for each field. Even if a field configuration is selected in units of two or more fields, the background luminance can be reduced. The number of input ports of the selector 94 may be three or more, and three or more external devices may be connected. Input signal is 3
Even if there are more than one, they may be classified into a still image signal and a moving image signal, and the still image mode or the moving image mode may be associated with each input signal. Further, three or more display modes may be provided, and an optimal field configuration may be selected for each of the display modes.

Although erase addressing has been exemplified in the above embodiment, the present invention is also applicable to the case where write addressing is performed.

[0061]

According to the first to fourth aspects of the present invention,
The range of applications in which the best display can be realized can be expanded. For example, for a still image, display with priority given to the number of display colors can be realized, and for a moving image, display with reduced false contours can be realized.

According to the second aspect of the present invention, a display with good contrast can be realized regardless of the brightness of the field.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a plasma display device according to the present invention.

FIG. 2 is a schematic diagram of field division.

FIG. 3 is a diagram showing field configuration options.

FIG. 4 is a time chart illustrating an example of lighting control.

FIG. 5 is a voltage waveform diagram showing an example of a driving sequence.

FIG. 6 is a diagram for explaining a method of determining a luminance distribution.

FIG. 7 is a diagram illustrating a selection procedure of a field configuration in a table format.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 plasma display device (display device) f field sf1 to 16 subfield C cell TA addressing period TS sustain period (lighting sustaining period) TR preparation period 92 luminance distribution determining circuit (distribution determining means) 81 controller (control means)

Claims (4)

[Claims] 1. One field is composed of three or more subfields weighted with luminance, and an addressing period for setting the necessity of lighting of each cell and a lighting maintenance period for maintaining a lighting state are provided for each subfield. A display device for allocating and classifying the set of subfields for one field into one or more subfield groups and allocating a preparation period for initializing display to the beginning of the subfield group to perform gradation display, There are provided first and second display modes. In the first display mode, gradation display is performed by applying a first field configuration to a field of interest to be displayed. In the second display mode, A display device, wherein gradation display is performed by applying a second field configuration having a maximum weight different from that of the first field configuration to the field of interest. 2. A plurality of field configurations having different numbers of subfield groups are provided for each of the first and second display modes, and a luminance distribution of one or more fields including the field of interest is calculated. A luminance discriminating means for discriminating the calculated luminance distribution in light of a setting condition; and one of the plurality of field configurations corresponding to the display mode selected for the field of interest according to a result of the determination of the luminance distribution. 2. The display device according to claim 1, further comprising: control means for selecting one of them and applying the selected one to the gradation display of the field of interest. 3. The display device according to claim 1, further comprising a selector for selecting one of a plurality of input signals as a display target, and setting a display mode in conjunction with the selection by the selector. 4. The display device according to claim 1, further comprising operation means for designating a display mode, wherein the display mode is set according to a state of the operation means.