WO2009090685A1

WO2009090685A1 - Plasma display unit

Info

Publication number: WO2009090685A1
Application number: PCT/JP2008/000034
Authority: WO
Inventors: Yoshinori Miyazaki
Original assignee: Hitachi, Ltd.
Priority date: 2008-01-17
Filing date: 2008-01-17
Publication date: 2009-07-23

Abstract

A plasma display unit has a display panel having a plurality of display electrodes and a plurality of address electrodes, a display electrode drive circuit, and an address electrode drive circuit. The display electrode drive circuit and the address electrode drive circuit apply a voltage corresponding to the display data to the address electrodes while applying scanning pulses sequentially to the display electrodes during the addressing period, apply the specified number of sustain pulses to the display electrodes during the sustain period after the addressing period, and repeat a drive of the subfield having an addressing period and a sustain period several times. The plasma display unit also has a display data processing section to which the video data is input and which generates the display data in accordance with the input video data. The display data processing section has a video data correction unit to correct a gray-scale value of the input video data for each display line at a correction ratio corresponding to a video load ratio of the display line, and a correction ratio generator unit to generate the correction ratio depending on the aging time of the display panel.

Description

Plasma display device

The present invention relates to a plasma display device, and more particularly to a plasma display device with reduced streaking phenomenon.

Plasma display devices are widely used as large-screen thin TVs. The panel drive control of the plasma display device is composed of an address period in which a display image is written in the cell, a sustain period in which the cell written in the address period is brightened, and a reset period in which the state of the wall charge of the cell is reset. The One frame image is displayed in grayscale by a plurality of subfields including a reset period, an address period, and a sustain period. By changing the number of times of light emission in the sustain period of each subfield and combining the subfields to be lit, multi-gradation display becomes possible.

A general plasma display panel has a plurality of pairs of X and Y electrodes extending in the horizontal direction and a plurality of address electrodes extending in the vertical direction. The X and Y electrodes are display electrodes, and a display line is formed by a pair of display electrodes composed of X and Y electrodes. In panel driving, write data is applied to the address electrode in the address period, a scan pulse is applied to the Y electrode to generate an address discharge to form wall charges in the cell, and alternately between the X and Y electrodes in the sustain period. A sustain pulse is applied to the cell to generate a sustain discharge in the written cell. As a result, luminance display according to the number of sustain pulses is made possible.

During the sustain period, the discharge current differs depending on the display load (or video load) corresponding to the number of cells that are lit on the same display line, and the cells in each display line are caused by the voltage drop due to the discharge current. Since the applied sustain voltages are different, it is known that even if the video signal has the same gradation value, the display line with a large display load has a lower luminance than the display line with a small display load. Such a phenomenon in which the luminance varies depending on the display load of the display line is called a streaking phenomenon.

In order to avoid this streaking phenomenon, it has been proposed to calculate the load for each display line based on the display data and correct the gradation value of the display data for each display line based on the load. For example, it is described in Patent Document 1. According to Patent Document 1, the gradation value is corrected for each emission color.
JP 2006-337720 A

The brightness correction described in Patent Document 1 is performed according to a preset correction coefficient. However, the light emission operation of the plasma display panel is accompanied by aging corresponding to the driving time. Therefore, the display line luminance difference due to the streaking phenomenon changes according to the panel drive time, and it is not possible to cope with secular change by just correcting the luminance with the correction factor set at the time of shipment from the factory, and the streaking phenomenon gets worse. .

The cause of this streaking phenomenon has not been elucidated exactly, but according to the knowledge of the present inventors, by repeating the driving of the plasma display panel, the sustain pulse is applied until the discharge occurs. One cause is considered to be a so-called discharge delay that takes longer time. It is assumed that the discharge delay is accompanied by fluctuations in the sustain pulse voltage when discharge occurs, causing fluctuations in the voltage drop in the display line, and fluctuations in luminance due to the streaking phenomenon.

Therefore, an object of the present invention is to provide a plasma display device that prevents the streaking phenomenon from being deteriorated by aging.

In order to achieve the above object, according to the first aspect of the present invention, a plasma display device includes a plurality of display electrodes arranged corresponding to a display line, a plurality of address electrodes intersecting the display electrodes, A display panel, a display electrode driving circuit for driving the display electrode, and an address electrode driving circuit for driving the address electrode. The display electrode driving circuit and the address electrode driving circuit apply a voltage corresponding to display data to the address electrode while sequentially applying a scan pulse to the display electrode in the address period, and in a sustain period after the address period. A predetermined number of sustain pulses are applied to the display electrode, and driving of the subfield having the address period and the sustain period is repeated a plurality of times. The plasma display device further includes a display data processing unit that inputs input video data and generates the display data based on the input video data, the display data processing unit corresponding to the video load factor of the display line. A correction unit that generates a correction rate in accordance with an aging time of the display panel; and a correction rate generation unit that corrects a gradation value of input video data for each display line at a correction rate.

According to the present invention, the correction rate for suppressing the streaking phenomenon is corrected according to the aging time.

According to a preferable aspect of the first aspect of the present invention, the display data processing unit calculates the aging time per unit time based on the number of sustain pulses and the video load factor, and The correction rate generation unit generates the correction rate in accordance with the accumulated aging time.

According to a preferred aspect of the first aspect of the present invention, the aging time calculation unit accumulates and stores a single aging time in the display panel.

According to a preferred aspect of the first aspect of the present invention, the aging time calculation unit accumulates and stores the aging time for each display line, and the correction factor generation unit performs the accumulation. The correction factor is generated for each display line in accordance with the secular change time.

According to a preferable aspect of the first aspect of the present invention, the display data processing unit calculates the aging time for each unit time based on the power of the display electrode driving circuit, and An arithmetic unit that accumulates and stores the secular change time is stored, and the correction rate generation unit generates the correction rate according to the accumulated age change time.

According to a preferable aspect in the first aspect of the present invention, the display data processing unit includes an aging table having a change in display luminance with respect to the aging time, and the correction factor generating unit includes the aging table. The correction rate is generated according to a change in the display brightness corresponding to the accumulated aging time with reference to a change table.

According to the present invention, since the correction factor for suppressing the streaking phenomenon is corrected according to the aging time, it is possible to suppress the streaking phenomenon from being deteriorated due to the aging change.

It is a panel block diagram of the plasma display apparatus in this Embodiment. It is sectional drawing of the panel of FIG. It is a block diagram of the drive circuit unit of the plasma display apparatus in this Embodiment. It is a figure which shows the panel drive of the plasma display apparatus in this Embodiment. It is a concrete drive waveform figure of the panel drive in this Embodiment. It is a figure explaining a streaking phenomenon. It is a figure which shows the structure of the control part in this Embodiment. It is a block diagram of the display data processing part in this Embodiment. 6 is a diagram showing an example of a pulse number table 56. FIG. It is a figure which shows an example of an electric power table. It is a figure which shows an example of the secular change table. It is a figure which shows an example of the correction table.

Explanation of symbols

10:

Display panel

30, 33, 34: Display electrode drive circuit 35: Address electrode drive circuit 36: Control unit 42: Display data processing unit Video: Input video data A-DATA: Display data

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof.

FIG. 1 is a panel configuration diagram of the plasma display device according to the present embodiment. In the plasma display panel 10, a front substrate 11 and a rear substrate 16 are arranged with a discharge space interposed therebetween. On the front substrate 11, a plurality of pairs of an X electrode composed of a transparent electrode 12 and a metal bus electrode 13 superimposed thereon, and a Y electrode composed of a transparent electrode 14 and a metal bus electrode 15 superimposed thereon are arranged. These X and Y electrodes are covered with a dielectric layer IFa. The X and Y electrodes constitute display electrodes, and the X and Y electrodes are arranged for each display line. Further, the rear substrate 16 has a plurality of address electrodes 17, partition walls 18 disposed between the address electrodes 17, and

phosphor layers

19R, 19G, and 19B provided on the address electrodes 17 and the partition walls 18. . The

phosphor layers

19R, 19G, and 19B are excited by ultraviolet rays that are generated when a discharge occurs in the discharge space, and emit red, green, and blue light, respectively. The emitted light passes through the

transparent electrodes

12 and 14 of the front substrate 11 and is emitted to the front side.

FIG. 2 is a cross-sectional view of the panel of FIG. FIG. 2 is a cross-sectional view taken along the address electrode 17 of FIG. 1 and is given the same reference numbers as FIG. That is, on the front substrate 11, an X electrode composed of the transparent electrode 12 and the metal bus electrode 13, a Y electrode composed of the transparent electrode 14 and the metal bus electrode 15, and a dielectric layer IFa covering them are formed. Further, a protective film 21 made of MgO and single crystal MgO particles 22 are disposed on the dielectric layer IFa. The MgO of the protective film 21 is a polycrystal formed by vapor deposition or sputtering, whereas the MgO particles 22 are single crystal.

On the rear substrate 16, address electrodes 17, a dielectric layer IFb covering the address electrodes 17, and a phosphor 19 are formed. In FIG. 2, the partition wall 18 is not shown.

FIG. 3 is a configuration diagram of the drive circuit unit of the plasma display device in the present embodiment. In the drawing, the panel 10 is shown in a state where the front substrate 11 and the rear substrate 16 overlap each other, and the X electrodes X1 to Xm and Y electrodes Y1 to Ym extending in the horizontal direction are alternately arranged to extend in the vertical direction. Address electrodes A1 to An are arranged.

The drive circuit unit includes an X electrode drive circuit 30 that drives the X electrode, a Y electrode drive circuit 32 that drives the Y electrode, an address electrode drive circuit 35 that drives the address electrode, and the

drive circuits

30, 32, and 35. And a control unit 36 that supplies a control signal to control the driving operation of the driving circuit. The X electrode drive circuit 30 and the Y electrode drive circuit 32 constitute a display electrode drive circuit. The X electrode drive circuit 30 has an X side common drive circuit 31 that applies a common drive pulse to all X electrodes, and the X side common drive circuit 31 applies a reset pulse and a sustain pulse to the X electrodes. The Y electrode drive circuit 32 includes a scan drive circuit 33 that sequentially applies a scan pulse to the Y electrodes Y1 to Ym, and a Y-side common drive circuit 34 that applies a reset pulse and a sustain pulse to the Y electrode.

The control circuit 36 receives the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync, the synchronization clock D-CLK, and the analog or digital video signal Video, and drive control signals 30S, 32S, and 35S necessary for driving the panel 10. Is supplied to each of the

drive circuits

30, 32, and 35. The control signal 35S to the address electrode drive circuit 35 includes display data generated for each subfield based on the video signal Video in addition to the drive control signal.

FIG. 4 is a diagram showing panel driving of the plasma display device according to the present embodiment. In the panel drive, one field FL has a plurality of subfields SF1 to SFn, and each subfield SF1 to SFn has a reset period Reset, an address period Tadd, and a sustain period Tsus. In the case of progressive driving in which one frame image is displayed by one vertical scan, the field FL and the frame are the same. On the other hand, in the case of interlaced driving in which one frame image is displayed by two vertical scans, two fields FL correspond to one frame.

FIG. 5 is a specific drive waveform diagram of the panel drive in the present embodiment. FIG. 5 shows a driving waveform of one subfield SF. In the state before the first reset period Treset starts, negative charges and positive charges are accumulated as wall charges on the X electrode of the cell that is lit in the sustain period Tsus of the immediately preceding subfield. In the first half of the reset period Treset, the X electrode drive circuit 30 applies the negative voltage −Vx to the X electrode while the address electrode drive circuit 35 keeps the address electrode at 0 V, and the Y electrode drive circuit 32 changes from 0 V to a predetermined value. A positive obtuse wave pulse PP is applied to the Y electrode, the potential of which increases with the slope of and reaches the positive ultimate voltage + Vyp. By applying this positive obtuse wave pulse PP, a reset discharge consisting of a weak discharge is generated between the X and Y electrodes of the cell that is lit in the immediately preceding sustain period. By this reset discharge, positive charges are formed on the X electrode and negative charges are formed on the Y electrode as wall charges.

Next, in the second half of the reset period Treset, the X electrode driving circuit 30 applies the positive voltage + Vx to the X electrode, and the Y electrode driving circuit 32 decreases the potential from the voltage + Vyp with a predetermined slope, resulting in a negative reached voltage − A negative blunt wave pulse NP reaching Vyn is applied to the Y electrode. By this negative blunt wave pulse NP, a weak discharge is generated between X and Y, and the wall charges on the X and Y electrodes accumulated by the reset discharge by the positive blunt wave pulse PP are reduced, and in the subsequent address period The wall charge amount is adjusted to be optimal for discharge. Further, by applying the negative blunt wave pulse NP, a weak discharge is generated between the address electrode and the Y electrode, and the wall charge on the address electrode is adjusted.

In the address period Tadd following the reset period Treset, the X electrode drive circuit 30 maintains the X electrode at the positive voltage + Vx, and the scan drive circuit 33 in the Y electrode drive circuit 32 applies a negative scan pulse to the Y electrodes Y1 to Ym− Vy is applied in order. Further, in synchronization with the application of the scan pulse −Vy2 to the Y electrode, the address electrode drive circuit 35 applies the address voltage Va to the address electrodes A1 to An corresponding to the display data. As a result, an address discharge is generated in the cell between the Y electrode to which the scan pulse −Vy2 is applied and the address electrode Va to which the address voltage Va is applied, and further, the Y to which the scan pulse −Vy2 is applied in that cell. Address discharge also occurs between the electrode and the X electrode. As a result, negative charges and positive charges are accumulated as wall charges on the dielectric layers of the X and Y electrodes of the cell in which writing is performed. An address discharge does not occur in a cell that has not been written, and remains in a reset state.

Finally, in the sustain period Tsus, the

common drive circuits

31 and 34 of the X and Y

electrode drive circuits

30 and 32 alternately apply the positive sustain pulse + Vs and the negative sustain pulse −Vs to the Y electrode and the X electrode. To do. When the sustain pulse is applied, the voltage applied between the X and Y electrodes is superimposed with the voltage due to the negative charge and the positive charge accumulated in the address period, and a sustain discharge is generated in the cell written in the address period. . The number of sustain pulses is set to a number corresponding to the luminance weight given to each subfield, and a sustain discharge occurs in the lighted cell in which the address discharge has occurred, and the luminance corresponding to each subfield is output. .

¡By appropriately combining lighting and non-lighting of a plurality of subfields, the luminance in the field or frame period can be made to correspond to the gradation value of the input video signal.

FIG. 6 is a diagram for explaining the streaking phenomenon. In the example of FIG. 6, different images are displayed in the five regions R1 to R5 of the display panel 10. The regions R1, R3, and R5 have the same first image load factor in which the video load factor for each display line (the ratio of the number of lighted cells to the total cell number) is the same. It has lighting areas B1, B2, B3, B4 and has a second video load factor lower than the first video load factor. The gradation values of the lighting areas in all the areas R1 to R5 are equal.

However, in regions R2 and R4, since the video load factor is low, the display brightness of regions other than dark or non-lighting regions B1 to B4 is high, and in regions R1, R3, and R5, the video load factor is high. The display brightness of the area is lower than the areas other than the areas B1 to B4 in the areas R2 and R4. This is because in regions R1, R3, and R5, the video load factor is high, so that the discharge current due to the sustain discharge increases, the voltage drop at the display electrode increases, and the voltage at the sustain discharge of each cell decreases. . Conversely, in regions R2 and R4, the video load factor is low, so the voltage drop due to the sustain discharge is small.

The video load factor is different for each subframe. In each subframe, when the video load factor is high, the number of lit cells increases, and the luminance of the subframe is lower than the original luminance. In the field period composed of a plurality of subframes, as the number of subframes having a high video load factor increases, the luminance in the field period decreases, resulting in a luminance difference from a region having a low video load factor.

FIG. 7 is a diagram showing a configuration of a control unit in the present embodiment. As described with reference to FIG. 3, the control unit 36 receives the video data signal Video composed of RGB grayscale signals, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the synchronization clock D-CLK. And are supplied. The control unit 36 monitors the drive power of the X electrode common drive circuit 30 and the Y electrode common drive circuit 34, and controls the number of sustain pulses so that the power does not exceed a predetermined reference level. , X electrode common drive circuit 30, Y electrode common drive circuit 34, scan drive circuit 33, driver control unit 41 for generating drive control signals for address electrode drive circuit 35, and input video data signal Video to address electrode And a display data processing unit 42 for generating display data A-DATA indicating address pulse application.

The power control unit 40 monitors the power consumption of the X and Y electrode

common drive circuits

30 and 34 during the sustain period, and controls the number of sustain pulses in each subframe to a specified number when the power consumption is low. When the value becomes higher, the number of sustain pulses in each subframe is controlled to be lower so that the power consumption does not exceed the reference level. Since the power consumption in the sustain period increases depending on the video load factor, according to the automatic power control by the power control unit 40, the sustain pulse number is controlled to be low when the video load factor is high. .

Then, the driver control unit 41 performs the sustain drive control of the X and Y electrode

common drive circuits

33 and 34 so that the sustain number of each subfield becomes the number of sustain pulses controlled by the power control unit 40.

The display data processing unit 42 generates display data of a plurality of subframes from the input video data signal Video having gradation values of RGB colors. For example, when the gradation value is “256” which is the maximum value at the time of 8-bit input, the display data of all subframes is “lighting = 1”, and when the gradation value is “128” which is the intermediate value, Among the plurality of subframes, the display data of the subframe that can generate the intermediate gradation “128” is “lighting = 1”, and the display data of the other subframes is “nonlighting = 0”.

Also, the display data processing unit 42 totals the video load factors for each display line and reduces the streaking effect, and performs correction based on the video load factors obtained by totaling the gradation values of the input video signal. By this correction, the gradation value of a display line with a low video load factor is further reduced, and the gradation value of a display line with a high video load factor is not reduced. That is, if the video load factor is smaller, the correction factor is lowered and the gradation value is greatly reduced. By performing such gradation value correction, it is possible to reduce the streaking effect in which a luminance difference occurs for each display line shown in FIG.

Further, the display data processing unit 42 varies the correction rate according to the aging time. Here, the aging time is the actual driving time that affects the aging of the light emission characteristics of the panel, and more specifically, the value obtained by multiplying the number of sustain pulses by the video load factor per unit time is accumulated. Value. Or it is the value which accumulated the power consumption in the sustain period for every unit time.

FIG. 8 is a configuration diagram of the display data processing unit in the present embodiment. The display data processing unit 42 includes a video load factor detection unit 50 that totals the video load factors for each display line, and an aging time calculation unit that calculates the aging time that is a substantial driving time that affects the aging of the discharge characteristics. 51, a correction factor generation unit 52 that generates a correction factor CR according to the video load factor of the display line, and a video data correction unit 53 that corrects the gradation value of the input video data signal Video based on the correction factor CR. And a display data generation unit 54 for generating display data A-DATA for each subframe from the corrected video data (corrected gradation value) CVideo.

Furthermore, the display data processing unit 42 has a memory 55 for storing various tables and aging time. This memory 55 is preferably a non-volatile memory that stores data even when the power is off. The memory 55 stores a pulse number table 56, an aging time memory 57, an aging table 58, and a correction table 59.

As described above, in the present embodiment, the video data correction unit 53 corrects the gradation value of the input video signal Video based on the correction rate CR in order to reduce the streaking effect. Further, the correction rate CR is changed and corrected by the correction rate generation unit 52 in accordance with the secular change of the discharge characteristics. This prevents the streaking effect from deteriorating due to aging.

Thus, in order to correct the correction rate CR according to the secular change, the aging time calculating unit 51 needs to count the substantial driving time corresponding to the secular change. Therefore, the calculation method of the aging time calculation unit 51 and the correction rate correction method by the correction rate generation unit 52 will be described below.

FIG. 9 is a diagram showing an example of the pulse number table 56. In the pulse number table 56, the horizontal axis represents the video load factor, and the vertical axis represents the number of sustain pulses × load factor. That is, the vertical axis corresponds to the number of sustain discharges actually generated. As the video load factor increases, the number of lighting cells increases and the number of lighting subfields increases. Therefore, as the video load factor increases, the number of sustain pulses on the vertical axis × load factor increases. However, when the load factor increases and the power increases due to the automatic power control by the power control unit 40, the number of sustain pulses in each subfield is reduced in order to suppress the power below a predetermined reference value. As a result, the number of sustain pulses on the vertical axis × load factor is limited to a constant value in the region where the video load factor is high.

The aging time calculation unit 51 refers to the pulse number table 56 based on the video load factor detected by the video load factor detection unit 50, accumulates the value of the number of sustain pulses on the vertical axis × the load factor, and determines the aging time. Is stored in the secular change time memory 57. The aging time calculation unit 51 obtains the aging time from the video load factor for each frame by referring to the pulse number table 56 for the number of sustain pulses × the load factor in that frame, and the accumulated value is obtained as the aging time. Store in memory 58. Thus, the aging time of the panel is stored in the aging time memory 58. The above is the first example of the aging time calculation.

As a modified example of the first example, in the second example of the aging time calculation, the aging time calculation unit 51 calculates the aging time from the video load factor of each display line × the number of sustain pulses of that display line × The value of the load factor is obtained by referring to the pulse number table, and the accumulated value is stored in the aging time memory 58 for each display line. Thus, the aging time memory 58 stores the aging time for each display line.

FIG. 10 is a diagram showing an example of the power table. In this power table, the horizontal axis represents the video load factor, and the vertical axis represents the total power of the X and Y electrode driving circuits or the total power including the address electrode driving circuit. As the video load factor increases, the number of lighting cells increases and the number of lighting subfields increases. Therefore, the power on the vertical axis increases as the video load factor increases. However, when the load factor increases and the power increases due to the automatic power control by the power control unit 40, the power is suppressed to a predetermined reference value or less. As a result, the power on the vertical axis is limited to a constant value in a region where the video load factor is high.

Since the power table of FIG. 10 has the same characteristics as the pulse number table of FIG. 9, the aging time calculation unit 51 uses the power table 56 of FIG. 10 based on the video load factor detected by the video load factor detection unit 50. The power value on the vertical axis may be accumulated and stored in the aging time memory 57 as the aging time.

FIG. 11 is a diagram showing an example of the secular change table 58. The horizontal axis shows the aging time, and the vertical axis shows the luminance difference between display lines with different video load factors. This aging table 58 is obtained by calculating the aging time corresponding to the number of sustain pulses × the load factor or the electric power obtained by the aging calculator 51 and the luminance difference between display lines in the streaking phenomenon described with reference to FIG. Showing the relationship. In other words, as the secular change time becomes longer, the luminance difference increases and eventually saturates to a constant value. The reason why the streaking phenomenon worsens due to secular change is, as described above, the delay of sustain discharge due to secular change.

According to this aging table 58, in order to suppress the deterioration of the streaking phenomenon, when the aging time elapses, the degree of correction of the gradation value of the input video signal Video is increased and the video load factor is increased. It is required to correct the tone value of the line lower.

In the present embodiment, the secular change table 58 is predicted in advance based on experimental data and stored in the memory 55.

FIG. 12 is a diagram illustrating an example of the correction table 59. The correction table shows the relationship between the vertical axis correction factor CR (0 to 1.0) and the horizontal axis display line video load factor. The solid line in the correction table 59 is the initial value of the correction factor CR, and the correction factor CR is set lower as the video load factor of the display line is lower. As a result, as described with reference to FIG. 6, it is possible to prevent the luminance from being increased at the display line having a low video load factor, the luminance from being decreased at the display line having a high video load factor, and the luminance difference between the display lines from being increased. . In the present embodiment, this correction table 59 is formed in advance and stored in the memory 55.

Furthermore, the broken line and the alternate long and short dash line in the correction table 59 indicate the correction rate corrected as the secular change time becomes longer. As shown in FIG. 11, the luminance difference between display lines due to the streaking phenomenon increases as the secular change time becomes longer. Accordingly, the correction rate generation unit 52 increases the correction rate CR of the correction table more accordingly. The data is corrected to a low level and supplied to the video data correction unit 53.

In the case of the first example in which the aging time calculating unit 51 accumulates the aging time of the panel and stores it in the aging time memory 57, the correction rate generation unit 52 performs the aging of the panel in the aging time memory 57. The change time is read out, a change in luminance difference is obtained by referring to the aging table 58, and the correction rate CR corresponding to the video load factor of the current display line in the correction table 59 is corrected correspondingly to correct the video data. Supply to unit 53. In this case, correction due to aging of the correction rate CR is similarly performed on all display lines in the panel.

On the other hand, in the case of the second example in which the aging time calculation unit 51 accumulates the aging time of each display line and stores it in the aging time memory 57, the correction rate generation unit 52 stores the aging time in the aging time memory 57. The current aging time of the current display line is read out, a change in luminance difference is obtained by referring to the aging table 58, and the correction rate CR corresponding to the video load factor of the current display line in the correction table 59 is correspondingly obtained. Is corrected and supplied to the video data correction unit 53. In this case, correction due to aging of the correction rate CR is performed individually for each display line in the panel. That is, on the premise that the secular change is different for each display line, the aging time calculation unit 51 obtains the aging time for each display line, and the correction rate generation unit 52 corrects the correction rate for each display line.

As described above, according to the present embodiment, the correction rate for suppressing the luminance difference between display lines having different video load factors due to the streaking phenomenon is corrected according to secular change. The deterioration of the streaking phenomenon is also suppressed by the secular change.

The present invention can obtain useful results when applied to a plasma display device.

Claims

A display panel having a plurality of display electrodes arranged corresponding to the display lines and a plurality of address electrodes intersecting the display electrodes;
A display electrode driving circuit for driving the display electrode;
A plasma display device having an address electrode driving circuit for driving the address electrode,
The display electrode driving circuit and the address electrode driving circuit apply a voltage corresponding to display data to the address electrodes while sequentially applying scanning pulses to the display electrodes during an address period, and perform the display during a sustain period after the address period. A predetermined number of sustain pulses are applied to the electrodes, and the driving of the subfield having the address period and the sustain period is repeated a plurality of times,
And a display data processing unit for inputting the input video data and generating the display data based on the input video data,
The display data processing unit includes a video data correction unit that corrects a gradation value of input video data for each display line at a correction rate corresponding to a video load factor of the display line, and a aging time of the display panel. And a correction rate generation unit for generating the correction rate.
In claim 1,
The display data processing unit calculates an aging time for each unit time based on the number of sustain pulses and the video load factor, and accumulates and stores the aging time for each unit time. Have
The plasma display apparatus according to claim 1, wherein the correction factor generation unit generates the correction factor according to the accumulated aging time.
In claim 2,
The plasma display apparatus, wherein the aging time calculation unit accumulates and stores a single aging time for the display panel.
In claim 2,
The aging time calculation unit accumulates and stores the aging time for each display line,
The plasma display apparatus according to claim 1, wherein the correction factor generation unit generates the correction factor for each display line according to the accumulated aging time.
In claim 1,
The display data processing unit has a calculation unit that calculates the aging time per unit time based on the power of the display electrode driving circuit, and accumulates and stores the aging time per unit time,
The plasma display apparatus according to claim 1, wherein the correction factor generation unit generates the correction factor according to the accumulated aging time.
In claim 2,
The display data processing unit has an aging table having a change in display luminance with respect to the aging time,
The plasma display apparatus, wherein the correction rate generation unit generates the correction rate according to a change in the display luminance corresponding to the accumulated aging time with reference to the aging table.