JP3896817B2 - Plasma display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display device that displays an image by controlling discharge.
[0002]
[Prior art]
FIG. 6 is a partial perspective view of a plasma display panel (hereinafter referred to as a panel). As shown in FIG. 6, a scanning electrode 4 and a sustaining electrode 5 covered with a dielectric layer 2 and a protective film 3 are arranged in parallel on the first glass substrate 1 in parallel with each other. . A data electrode 8 covered with an insulator layer 7 is provided on the second glass substrate 6, and a partition wall 9 is provided in parallel with the data electrode 8 on the insulator layer 7 between the data electrodes 8. . Further, the phosphor 10 is provided from the surface of the insulator layer 7 to the side surface of the partition wall 9, and the first glass substrate 1 and the second glass substrate so that the scan electrode 4, the sustain electrode 5, and the data electrode 8 are orthogonal to each other. 6 is disposed so as to face the discharge space 11 and the discharge space 11 is filled with a discharge gas. A discharge cell 12 is formed in the discharge space at the intersection of the scan electrode 4 and the sustain electrode 5 that are sandwiched between the two adjacent barrier ribs 9 and face the data electrode 8.
[0003]
FIG. 7 shows an example of a time schedule configuration in a conventional driving method for driving this panel, and FIG. 8 shows an operation timing diagram. In this driving method, one field is composed of a plurality of subfields, for example, eight subfilled, and these subfields are each composed of an initialization period, a writing period, a sustain period, and an erasing period.
[0004]
Next, the writing operation in the writing period in the conventional driving method shown in FIG. 8 will be described. As shown in FIG. 8, the wall charges effective in the subsequent writing period are transferred to all the scan electrodes in the initializing period at the beginning of the field. After accumulation in SCN1 to SCNN, all sustain electrodes SUS1 to SUSN, and data electrodes D1 to DM, all scan electrodes SCN1 to SCNN are set to Vs (V) and all sustain electrodes SUS1 to SUSN are set to Vh in the writing period. The positive write pulse electrode Vw (V) is scanned in the first row to a predetermined data electrode corresponding to the discharge cell 12 to be displayed in the first row among the data electrodes D1 to DM held in (V). A scan pulse voltage 0 (V) is applied to the electrode SCN1.
[0005]
At this time, the voltage between the surface of the insulator layer 7 and the surface of the protective film 3 on the scan electrode SCN1 at the intersection of the predetermined data electrode and the scan electrode SCN1 is set to the write pulse voltage Vw (V). Since the positive wall voltage on the surface of the insulator layer 7 on the data electrode is added, at this intersection, between the predetermined data electrode and the scan electrode SCN1, and between the sustain electrode SUS1 and the scan electrode SCN1 An address discharge occurs, a positive voltage is accumulated on the surface of the protective film 3 on the scan electrode SCN1 at the intersection, a negative voltage is accumulated on the surface of the protective film 3 on the sustain electrode SUS1, and the data discharge occurs on the data electrode. A negative voltage is accumulated on the surface of the insulator layer 7.
[0006]
The same operation is continuously performed in the second and subsequent rows. Finally, among the data electrodes D1 to DM, a positive write pulse voltage Vw is applied to a predetermined data electrode corresponding to the discharge cell 12 to be displayed in the Nth row. Scan pulse voltage 0 (V) is applied to scan electrode SCNN in the Nth row. At this time, an address discharge occurs between the predetermined data electrode and the operation electrode SCNN and between the sustain electrode SUSN and the scan electrode SCNN at the intersection between the predetermined data electrode and the scan electrode SCNN. A positive voltage is accumulated on the surface of the protective film 3 on the electrode SCNN, a negative electrode is accumulated on the surface of the protective film 3 on the sustain electrode SUSN, and a negative voltage is generated on the surface of the insulator layer 7 on the data electrode where the write discharge has occurred. Accumulated. Thus, the writing operation in the writing period is completed.
[0007]
Further, the light emission sustaining operation in the light emission sustaining period in the conventional driving method shown in FIG. 8 will be described. As shown in FIG. 8, in the light emission sustaining period following the writing period, first, all the scan electrodes SCN1 to SCNN and the sustaining electrode SUS1. After sustaining -SUSN at 0 (V), when positive sustain pulse voltage Vm (V) is applied to all scan electrodes SCN1-SCNN, protective film 3 on scan electrode 4 in discharge cell 12 in which the write discharge has occurred The voltage between the surface of the protective film 3 and the surface of the protective film 3 on the sustain electrode 5 is the sustain pulse voltage Vm (V), the positive wall voltage of the protective film 3 on the scan electrode 4 accumulated during the writing period and the sustain voltage. The negative wall voltage accumulated on the surface of the protective film 3 on the electrode 5 is added and exceeds the discharge start voltage.
[0008]
For this reason, in the discharge cell 12 in which the write discharge has occurred, a sustain discharge occurs between the scan electrode 4 and the sustain electrode 5, and on the surface of the protective film 3 on the scan electrode 4 in the discharge cell 12 in which the sustain discharge has occurred. A negative wall voltage is accumulated, and a positive wall voltage is accumulated on the surface of the protective film 3 on the sustain electrode 5. Thereafter, the sustain pulse voltage returns to 0 (V).
[0009]
Subsequently, when a positive sustain pulse voltage Vm (V) is applied to all sustain electrodes SUS1 to SUSN, the surface of the protective film 3 on the scan electrode 4 and the protection on the sustain electrode 5 in the discharge cell 12 in which the sustain discharge has occurred. The voltage between the surface of the film 3 is the sustain pulse voltage Vm (V), the negative wall voltage on the surface of the protective film 3 on the operation electrode 4 accumulated by the last sustain discharge, and the protection on the sustain electrode 5. The positive wall voltage accumulated on the surface of the film 3 is added.
[0010]
For this reason, in the discharge cell 12 in which the sustain discharge has occurred immediately before, a sustain discharge occurs between the scan electrode 4 and the sustain electrode 5, and the protective film 3 on the scan electrode 4 in the discharge cell 12 in which the sustain discharge has occurred. A positive wall voltage is accumulated on the surface, and a negative wall voltage is accumulated on the surface of the protective film 3 on the sustain electrode 5. Thereafter, the sustain pulse voltage returns to 0 (V).
[0011]
Similarly, the sustain discharge is continuously performed by alternately applying the positive sustain pulse voltage Vm (V) to all the scan electrodes SCN1 to SCNN and all the sustain electrodes SUS1 to SUSN.
[0012]
FIG. 9 shows a gradation expression method of a conventional plasma display apparatus, which will be described below. Since the plasma display device uses the discharge phenomenon, the discharge cell 12 has only two states of lighting and non-lighting. Therefore, one field is divided into a plurality of subfields in order to perform halftone gradation expression, each subfield is given a weight corresponding to light emission luminance, and the presence or absence of light emission is controlled for each field. Tone expression.
[0013]
For example, as shown in FIG. 9, one field is divided into six subfields, and the emission luminance weights of the respective subfields SF1 to SF6 are “1”, “2”, “4”, “8”, “16”. , “32”. In the case of expressing the gradation “31”, in the writing period in SF 1, SF 2, SF 3, SF 4, and SF 5, a wall charge that effectively acts on the subsequent light emission maintaining operation is formed in the discharge cell 12 and accumulated in each electrode. By performing the writing operation accompanied by the discharge, the light emission maintaining operation corresponding to the weights “1”, “2”, “4”, “8”, and “16” of the subfields is performed. Is expressed.
[0014]
In the case of expressing the gradation “63”, the light emission maintaining operation corresponding to the gradation “63” is performed by performing the writing operation in SF1 to SF6. In this way, when expressing the gradation “63”, the light emission maintaining operation is performed in SF1 to SF5 and the light emission maintaining operation is also performed in SF6 in addition to expressing the gradation “31”.
[0015]
[Problems to be solved by the invention]
However, when the light emission sustain operation is performed a predetermined number of times or more in the light emission sustain period, the discharge gas in the discharge cell 12 is activated, and the surface of the protective film 3 on the scan electrode SCNN and the surface of the insulating layer 7 on the data electrode Each of the wall voltages stored in is easily weakened. In this case, wall charges effective in the subsequent writing period accumulated in all the scan electrodes SCN1 to SCNN, all the sustain electrodes SUS1 to SUSN, and all the data electrodes D1 to DM in the initialization period at the beginning of the field are In some cases, after the initialization operation is completed, it is weakened before the actual write operation is performed in the write period, and a normal write operation may not be performed.
[0016]
In this case, wall charges that effectively act on the subsequent light emission sustaining operation cannot be normally accumulated, so that the light emission sustaining operation cannot be performed, and this corresponds to the weight of the subfield in which the writing operation cannot be performed normally. The gradation cannot be expressed. For example, one field is composed of six subfields whose emission luminance weights from subfields SF1 to SF6 are “1”, “2”, “4”, “8”, “16”, and “32”, respectively. In the case where the gradation “63” is expressed by performing the light emission maintenance operation in the light emission maintenance period from SF1 to SF6, first, the light emission maintenance operation is performed 31 times in total from SF1 to SF5. In this case, since the discharge gas in the predetermined discharge cell 12 is sufficiently activated, the wall charge accumulated in each electrode is weakened until the writing operation is actually performed in the subsequent writing period of SF6.
[0017]
Therefore, since the writing operation in the writing period of SF6 cannot be normally performed, the gradation is “31”, and the difference from the gradation that is actually expressed is “32”, so that the image quality is deteriorated. There was a problem. In addition, there is a correlation between the number of write operations in the subfield write period and the power consumption of the data driver module, and there is a problem that the power consumption of the data driver module increases due to an increase in the write operation.
[0018]
The present invention has been made in view of the above problems, and an object thereof is to prevent gradation deterioration.
[0019]
[Means for Solving the Problems]
In order to solve the above problems, in the plasma display device, the presence or absence of a writing operation in a writing period in which a writing operation and a light emission sustaining operation are performed and a subfield having a light emission sustaining period precede the predetermined subfield. It is configured to be determined by the number of subfield emission maintaining operations and the input signal corresponding to the video data to be displayed.
[0020]
Accordingly, when the discharge gas in the predetermined discharge cell is sufficiently activated by the light emission maintenance operation up to the previous stage, the normal write operation cannot be performed in the write period of the subsequent subfield, and the subsequent light emission maintenance operation is performed. It is possible to prevent the deterioration of gradation that cannot be performed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  That is, a plasma display device according to claim 1 of the present invention includes a plasma display panel in which column electrodes are arranged so as to intersect with a pair of first and second row electrodes and discharge cells are formed at the intersecting portions. And a driving circuit for driving the plasma display panel, and performing a writing operation for selecting lighting and non-lighting of the discharge cells by applying a voltage pulse to the column electrode in the writing period, and performing the writing operation. In the cell, a plasma display apparatus that performs a light emission maintenance operation in a light emission maintenance period by subsequently applying a voltage pulse to the row electrode,For a given subfieldThe presence / absence of a writing operation is determined by the number of light emission maintaining operations in a subfield preceding the predetermined subfield and an input signal corresponding to video data to be displayed.When the total number of times of the light emission maintaining operations of the plurality of subfield groups preceding the predetermined subfield is larger than the predetermined number, the predetermined subfield is not turned on, and writing is continuously performed. When the total number of times of the light emission maintaining operations of the plurality of subfield groups preceding the predetermined subfield performing the operation and the light emission maintaining operation is larger than the predetermined number of times, the predetermined subfield is turned off.It is composed. Accordingly, when the discharge gas in the predetermined discharge cell is sufficiently activated by the light emission maintenance operation up to the previous stage, the normal write operation cannot be performed in the write period of the subsequent subfield, and the subsequent light emission maintenance operation is performed. It is possible to prevent the deterioration of gradation that cannot be performed.
[0022]
  According to a second aspect of the present invention, there is provided a plasma display panel in which column electrodes are arranged so as to intersect with a pair of first and second row electrodes, and discharge cells are formed at the intersecting portions. And a driving circuit for driving the plasma display panel, and performing a writing operation for selecting lighting and non-lighting of the discharge cells by applying a voltage pulse to the column electrode in the writing period, and performing the writing operation. In the cell, a plasma display apparatus that performs a light emission sustaining operation in a light emission sustaining period by subsequently applying a voltage pulse to the row electrode, wherein the presence or absence of a write operation in the first subfield of a predetermined field Number of times of light emission maintenance operation in the field immediately before the subfield and display The number of times that the light emission maintaining operation is performed in a plurality of consecutive subfield groups including the subfield arranged last among the subfields constituting the immediately preceding field. Is greater than the predetermined number of times, the first subfield of the predetermined field is not lit. Thereby, when the discharge gas in the predetermined discharge cell is sufficiently activated by the light emission maintaining operation in the immediately preceding field, the wall voltage is weakened in the writing period of the subfield arranged at the beginning of the subsequent field, It is possible to prevent gradation deterioration that a normal writing operation cannot be performed and a subsequent light emission maintaining operation cannot be performed.
[0025]
Note that the number of light emission maintaining operations for determining whether or not the subfield writing operation is performed is 30 times.
[0026]
Hereinafter, a plasma display device according to an embodiment of the present invention will be described with reference to FIGS.
[0027]
(Embodiment 1)
FIG. 2 shows a configuration diagram of the plasma display device according to the first embodiment of the present invention.
[0028]
The plasma display device shown in FIG. 2 includes a plasma display panel 21, a data driver 22, a scanning driver 23, a sustain driver 24, and a data detection conversion unit 25.
[0029]
As shown in FIG. 6, the plasma display panel 21 has a plurality of data electrodes 8 that are column electrodes, a plurality of scan electrodes 4 that are first row electrodes, and a plurality of sustain electrodes 5 that are second row electrodes. The plurality of data electrodes 8 are arranged in the vertical direction of the screen, and the plurality of scanning electrodes 4 and the plurality of sustain electrodes 5 are arranged in the horizontal direction of the screen. The plurality of sustain electrodes 5 are connected in common, and discharge cells 12 are formed at the intersections of the data electrodes 8, the scan electrodes 4, and the sustain electrodes 5, and each discharge cell 12 has a pixel on the screen. It is composed. A discharge gas is sealed inside the discharge cell 12.
[0030]
The data driver 22 is connected to the plurality of data electrodes 8 of the plasma display panel 21, the scan driver 23 is connected to the plurality of scan electrodes 4 of the plasma display panel 21, and the sustain driver 24 is connected to the plasma display panel 21. The plurality of sustain electrodes 5 are connected. The data detection conversion unit 25 is connected to the data driver 22, the scan driver 23, and the maintenance driver 24.
[0031]
The scan driver 23 can perform stable initialization discharge, write discharge, sustain discharge, and erase discharge in all the discharge cells 12 in the initialization period, the write period, and the erase period including the sustain period of each subfield. Pulses for initialization operation, sustain operation, write operation, and erase operation are applied to the plurality of scan electrodes 4, respectively. Further, the sustain driver 24 can perform a stable initializing discharge, writing discharge, sustaining discharge and erasing discharge in all the discharge cells 12, so that the initializing period including the sustaining period of each subfield, the writing period and the erasing period. , Pulses for initialization operation, sustain operation, write operation and erase operation are applied to the plurality of sustain electrodes 5, respectively.
[0032]
In addition, the data driver 22 has a plurality of data in accordance with the video signal input through the data detection conversion unit 25 during the writing period of each subfield so that stable writing discharge can be performed in all the discharge cells 12. A write voltage pulse that is turned on or off is applied to the electrode 8. Thereby, the initialization operation, the sustain operation, the write operation, and the erase operation are performed in the predetermined discharge cell 12.
[0033]
FIG. 1 shows a write operation and a light emission state in each subfield in driving the plasma display device of FIG. It should be noted that the timetable configuration diagram for driving the plasma display panel, and the drive voltages and operation timings applied to the scan electrodes, sustain electrodes, and data electrodes are the same as those shown in FIGS.
[0034]
As shown in FIG. 1, one field is divided into eight subfields SF1 to SF8, and the emission luminance weight of each subfield is set to “1”, “2”, “ When “4”, “8”, “16”, “32”, “64”, and “128” are set, a maximum of 256 gradations can be expressed by a combination of all subfields. For example, when the gradation “31” is expressed, the subsequent light emission maintaining operation can be normally performed by performing the writing operation in the writing period of the subfields SF1, SF2, SF3, SF4, and SF5. 31 "can be expressed. Further, when expressing the gradation “32”, the writing operation is performed only in the writing period of SF6, and the subsequent light emission maintaining operation is performed.
[0035]
Here, when expressing the gradation “63”, the writing operation and the light emission maintaining operation are performed in SF1 to SF5, and the writing operation is also performed in the subsequent SF6. However, since the discharge gas in the predetermined discharge cell 12 is sufficiently activated by the light emission maintaining operation up to SF5, the wall voltage accumulated in each electrode forming the predetermined discharge cell 12 in the writing period of SF6 is very high. In the actual writing operation, the normal writing operation cannot be performed, and the light emission maintaining operation may not be performed in the subsequent light emission maintaining period.
[0036]
At this time, since the predetermined discharge cell 12 performs the light emission maintaining operation only from SF1 to SF5, the actually expressed gradation is “31”. Here, when the number of times that the light emission maintaining operation has been performed up to the previous stage is a predetermined number or more and the discharge gas in the discharge cell 12 is sufficiently activated, the writing operation is not performed in the subfield arranged immediately after that. The gradation is expressed by performing the writing operation in the writing period of the subfield.
[0037]
As a result, it is possible to prevent deterioration in gradation due to a writing failure in the writing period of the subfield arranged immediately after. The number of times of the light emission maintaining operation until the discharge gas in the discharge cell 12 is sufficiently activated varies depending on the discharge characteristics of the panel, but a value larger than 30 times is preferable. Thereby, it is possible to accurately express a relatively low gradation. Further, gradation errors occur by using other subfields. In such a case, the influence can be reduced by signal processing such as an error diffusion method or a dither method.
[0038]
That is, when the gradation “63” is expressed, the light emission maintaining operation is performed only in the gradation “61” and the SF7 light emission maintaining period that can be expressed by performing the light emission maintaining operation in the light emission maintaining periods of SF1, SF3, SF4, SF5, and SF6 It can be expressed by signal processing using peripheral gradations such as gradation “64” that can be expressed by performing the above, and gradation “65” that can be expressed by performing the light emission maintaining operation in the light emission maintaining period of SF1 and SF7. Here, the writing operation is continuously performed in SF3 to SF6. In this case, the total number of times of the light emission maintaining operation from SF3 to SF5 is “28”, so that the discharge gas in the predetermined discharge cell 12 is still sufficient. In the writing period of the SF 6 that is not activated and immediately after the SF 6 is disposed, each electrode forming the predetermined discharge cell 12 is accumulated enough to perform the writing operation. It can be performed.
[0039]
Next, a case where the subfield arranged immediately after the subfield to be subjected to the light emission maintaining operation is turned off when the number of light emission maintenance operations of the subfield to be operated to maintain the light emission is larger than a predetermined number will be described below.
[0040]
For example, as shown in FIG. 1, when the gradation “48” is expressed, the writing operation is performed in the writing period of SF5 and SF6 to perform the subsequent light emission maintaining operation, thereby expressing the gradation “48”. At this time, since the number of times of the light emission sustaining operation in the light emission sustaining period of SF5 is “16”, the discharge gas in the predetermined discharge cell 12 is not sufficiently activated. Normal writing operation can be performed.
[0041]
On the other hand, when the gradation “96” is expressed, the writing operation is performed in the writing period of SF6 and SF7, and the gradation “96” is expressed by the subsequent light emission maintaining operation, but the light emission maintaining in the light emission maintaining period of SF6 is performed. Since the number of times is “32”, the discharge gas in the predetermined discharge cell 12 is sufficiently activated, and the wall voltage accumulated on each electrode forming the predetermined discharge cell in the initialization period is very weak. It is easy to be done. For this reason, a normal write operation may not be performed during the write period of SF7.
[0042]
That is, when the number of times of the light emission maintaining operation is not less than the predetermined number as in SF6 and the discharge gas in the predetermined discharge cell 12 is sufficiently activated, the writing operation is not performed in the subfield arranged immediately after that, The gradation is expressed by performing the writing operation in the writing period of the subfield. As a result, it is possible to prevent deterioration in gradation due to a writing failure in the writing period of the subfield arranged immediately after. Note that the number of times of the light emission sustaining operation until the discharge gas in the discharge cell 12 is sufficiently activated varies depending on the discharge characteristics of the panel as described above, but is preferably a value larger than 30 times. Expression can be performed accurately.
[0043]
In addition, an error in gradation is caused by using other subfields. In such a case, the influence of the error can be reduced by signal processing such as an error diffusion method or a dither method. Even if the light emission luminance weights of the subfields constituting one field are not the values shown in FIG. 1, the same effect can be obtained as long as the light emission luminance weights can be used for gradation display using each subfield. .
[0044]
(Embodiment 2)
FIG. 5 shows a block diagram of a plasma display device according to Embodiment 2 of the present invention. In FIG. 5, the same parts as those shown in FIG.
[0045]
That is, the plasma display device shown in FIG. 5 includes a plasma display panel 21, a data driver 22, a scan driver 23, a sustain driver 24, a data detection conversion unit 25, and a field memory 26. The field memory 26 is a data detection conversion unit. 25. Then, the data detection conversion unit 25 reads the data from the field memory 26 that stores the display state in the immediately preceding field, thereby converting the data into a video signal that can be applied with appropriate voltage pulses to the plurality of data electrodes 8. A signal is sent to the data driver 22. Other operations are the same as those shown in FIG.
[0046]
FIG. 3 shows a write operation and a light emission state of each subfield in the driving of the plasma display device of FIG. It should be noted that the timetable configuration diagram, the driving voltage applied to the scan electrode, the sustain electrode, and the data electrode and the operation timing in driving the plasma display panel are the same as those shown in FIGS.
[0047]
As shown in FIG. 3, for each of the two fields, one field is divided into eight subfields SF11 to SF18, and SF21 to SF28, and the emission luminance weight of each subfield is set to the time from the start of each field. If “1”, “2”, “4”, “8”, “16”, “32”, “64”, and “128” are set in order, the maximum number of floors is 256 depending on the combination of all subfields. Keys can be expressed.
[0048]
Here, when the number of times of the light emission maintaining operation in the last subfield SF18 arranged in the immediately preceding field is “128”, the discharge gas in the predetermined discharge cell 12 is sufficiently activated, and the predetermined period in the initialization period Since the wall voltage accumulated on each electrode forming the discharge cell is very easily weakened, a normal write operation is performed in the write period of the subfield SF21 arranged at the head of the immediately following field. It may not be possible.
[0049]
In this case, as in SF18, when the number of light emission maintaining operations in the subfield arranged at the end of the field is equal to or greater than a predetermined number and the discharge gas in the predetermined discharge cell 12 is sufficiently activated, the data detection conversion unit 25 and the field memory 26, the number of light emission maintaining operations in the immediately preceding field is taken into consideration, the writing operation is not performed in the first subfield arranged in the immediately following field, and the writing operation is performed in the writing period of the other subfield. By expressing the gradation by performing the above, it is possible to prevent deterioration in gradation due to a writing failure in the writing period of the subfield arranged at the beginning of the immediately following field.
[0050]
Note that the number of times of the light emission maintaining operation until the discharge gas in the discharge cell 12 is sufficiently activated varies depending on the discharge characteristics of the panel, but a value larger than 30 is preferable as described above. In addition, an error in gradation is caused by using other subfields. In such a case, if the gradation is expressed with less influence by signal processing or the like, the light emission of the subfields constituting one field is further increased. Even if the luminance weight is not the value shown in FIG. 3, the same effect can be obtained as long as the luminance luminance weight allows gradation display using each subfield.
[0051]
Next, another control example in the present invention will be described with reference to FIG. In FIG. 4, the writing operation and the light emission maintaining operation are continuously performed in a plurality of continuous subfield groups having a subfield arranged at the end of the field among the subfields constituting one field in the immediately preceding field. A case will be described in which the subfield arranged at the beginning of the subsequent field is turned off when the number of times that the light emission maintaining operation is performed is larger than the predetermined number.
[0052]
For example, as shown in FIG. 4, for each of the two fields, one field is divided into eight subfields SF11 to SF18 and SF21 to SF28, and the weight of the emission luminance of each subfield is set temporally from the start of the field. When “1”, “2”, “4”, “8”, “16”, “48”, “32”, and “28” are set in order from the earliest, a maximum of 140 gradations can be obtained by combining all subfields. It can be expressed.
[0053]
As shown in FIG. 4, in the light emission sustain period of the subfield SF18 arranged last in the immediately preceding field, when SF17 and SF18 do not continuously perform the light emission sustain operation in the case of performing the light emission sustain operation, for example, the gradation “ In the case of expressing “59”, since the number of times of the emission maintaining operation of only the SF 18 is “28”, the discharge gas in the predetermined discharge cell 12 is not sufficiently activated when the process proceeds to the subsequent field. In the writing period of the subfield SF21 arranged at the beginning of the field, normal writing operation can be performed.
[0054]
On the other hand, when a plurality of subfields including the subfield SF18 arranged last in the immediately preceding field perform the light emission sustaining operation, for example, when expressing the gradation “61”, SF17 and SF18 Since the light emission maintenance operation is continuously performed in the light emission maintenance period and the total number of the light emission maintenance operations is “52”, the discharge gas in the predetermined discharge cell 12 is sufficiently activated, and in the initialization period. Since the wall voltage accumulated on each electrode forming a predetermined discharge cell is very easily weakened, normal writing operation is performed in the writing period of the subfield SF21 arranged at the head of the immediately following field. May not be able to do.
[0055]
Here, as in SF17 and SF18, the subfield arranged at the end of the field is used to continuously perform the light emission sustaining operation, and the number of times of the light emitting sustaining operation is equal to or greater than the predetermined number. When the discharge gas in the inside is sufficiently activated, the data detection conversion unit 25 and the field memory 26 are used to consider the number of light emission maintaining operations in the immediately preceding field, and writing is performed in the first subfield arranged in the immediately following field. By performing the write operation in the write period of the other subfield without performing the operation, the gradation is deteriorated due to the write failure in the write period of the subfield arranged at the head of the immediately following field. Can be prevented.
[0056]
In this case as well, the number of times of sustaining the light emission until the discharge gas in the discharge cell 12 is sufficiently activated is preferably greater than 30 times. Further, the use of other subfields causes gradation errors. In such a case, the gradation may be expressed with less influence by signal processing or the like. Further, even if the light emission luminance weights of the subfields constituting one field are not the values shown in FIG. 4, the same effect can be obtained as long as the light emission luminance weights can be used for gradation display using each subfield. can get.
[0057]
【The invention's effect】
As described above, in the plasma display device of the present invention, the presence or absence of the write operation in the subfield having the write period and the light emission sustain period in which the write operation and the light emission sustain operation are performed is maintained by the previous subfield or the previous subfield group. It is configured to be determined by the number of operations and a signal corresponding to video data to be displayed, and a normal writing operation cannot be performed in the writing period of the subsequent subfield due to the light emission maintaining operation up to the previous stage. It is possible to prevent gradation deterioration that the light emission maintaining operation cannot be performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a write operation and a light emission state of each subfield in a plasma display device according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the plasma display device.
FIG. 3 is an explanatory diagram showing an example of a write operation and a light emission state in each subfield in the plasma display device according to the second embodiment of the present invention.
FIG. 4 is an explanatory diagram showing another example of the write operation and the light emission state of each subfield.
FIG. 5 is a block diagram showing the configuration of the plasma display device.
FIG. 6 is a perspective view showing an example of a plasma display panel.
FIG. 7 is an explanatory diagram showing a configuration of a driving timetable of the plasma display device
FIG. 8 is a signal waveform diagram showing drive voltages and operation timings applied to scan electrodes, sustain electrodes, and data electrodes in a plasma display device.
FIG. 9 is an explanatory diagram showing a write operation and a light emission state of each subfield in a conventional plasma display device.
[Explanation of symbols]
4 Scanning electrodes
5 Maintenance electrode
8 Data electrode
11 Discharge space
12 Discharge cell
21 Plasma display panel
22 Data driver
23 Scanning driver
24 maintenance drivers
25 Data detection converter
26 Field memory

Claims (2)

A plasma display panel in which column electrodes are arranged so as to intersect with a pair of first and second row electrodes and discharge cells are formed at the intersecting portions, and a driving circuit for driving the plasma display panel, and a writing period By applying a voltage pulse to the column electrode in FIG. 1, a write operation for selecting lighting and non-lighting of the discharge cell is performed, and in the discharge cell that has performed this write operation, by subsequently applying a voltage pulse to the row electrode, A plasma display apparatus performing a light emission maintenance operation in a light emission maintenance period, wherein the presence / absence of a write operation in a predetermined subfield depends on the number of light emission maintenance operations in a subfield preceding the predetermined subfield and the video data to be displayed. configured to determine the corresponding input signal, said predetermined sub If the sum of the number of the plurality of subfield groups of the light-emitting sustain operation preceding the field is greater than the predetermined number, the plasma display apparatus characterized by being configured such that the non-lighting the predetermined subfield. A plasma display panel in which column electrodes are arranged so as to intersect with a pair of first and second row electrodes and discharge cells are formed at the intersecting portions, and a driving circuit for driving the plasma display panel, and a writing period By applying a voltage pulse to the column electrode in FIG. 1, a write operation for selecting lighting and non-lighting of the discharge cell is performed, and in the discharge cell that has performed this write operation, by subsequently applying a voltage pulse to the row electrode, A plasma display apparatus that performs a light emission sustaining operation during a light emission sustaining period, and the presence / absence of a write operation in the first subfield of a predetermined field should be displayed and the number of times of the light emission sustaining operation in the field immediately before the predetermined subfield Configured to be determined by input signal corresponding to video data If the number of times that the light emission maintaining operation is performed in a plurality of consecutive subfield groups including the subfield arranged last among the subfields constituting the immediately preceding field is greater than a predetermined number, the first of the predetermined field A plasma display device characterized in that the sub-field is not lit.

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