JPH08160912A - Method and device for compensating luminance of plasma display - Google Patents

Abstract

PURPOSE: To reduce the luminance fluctuation due to the number of lighting display cells by performing a luminance compensation while independently controlling the frequency of maintaining discharge in every scanning line. CONSTITUTION: A luminance compensating circuit is provided with a counter 1 counting the number of display data D for every scanning line, a memory 4 storing the counted value D11, a counter 2 counting the number of scanning times, a counter 3 counting the number of maintaining times, a selector 5 selecting either the counter value S11 or the counted value S12, a memory 6 storing timing data of maintaining discharge stopping and comparators 7 comparing outputs data MD1 to MDj with the S12 to output maintaining stopping signals SD1 to SDj. Then, the distribution of display data for every compensating unit display line is detected and the frequency of maintaining discharge for obtaining a desired luminance every compensating unit display line is calculated by performing a calculation with a predetermined luminance fluctuation coefficient in accordance with the distribution of display data and maintaining discharges are stopped when maintaining discharge frequencies are completed every compensating unit display line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display, and more particularly to compensating a brightness variation due to a load variation applied to a sustain pulse driving circuit of a memory type plasma display.

[0002]

2. Description of the Related Art Plasma display panels (PDPs)
Has many features such as thin structure, no flicker, relatively large screen, fast response speed, self-luminous type, and multicolor emission by using phosphors. It is becoming widely used in the fields of related display devices and color image displays.

There are two types of PDP, an AC discharge type in which an electrode is covered with a dielectric and is indirectly operated in an AC discharge state, and an electrode is exposed in a discharge space to directly discharge the PDP. There is a direct current discharge (PDP) type which operates. Further, AC type driving includes a memory type that uses a memory of a discharge cell and a refresh type that does not use the discharge cell memory as a driving method.

Referring to FIG. 13 showing a cross sectional structure of one display cell of an AC memory type PDP, this PDP has a first insulating substrate 39 made of glass, a second insulating substrate 45 also made of glass, a scanning electrode 37, A sustain electrode 40, a data electrode 44, a discharge gas space 38 filled with He, Ne, Xe, or the like or a mixed gas thereof, a barrier 35 that secures the discharge gas space 38 and separates display cells, and is generated by discharge of discharge gas. Phosphor 4 that converts ultraviolet light into visible light
2. Insulator 36 covering the scan electrodes and sustain electrodes, insulator 3
A protective film 41 made of magnesium oxide or the like for protecting 6 from discharge, and an insulator 42 for covering the data electrode are provided.

Next, the discharge operation of the selected display cell will be described. When a pulse voltage exceeding the discharge threshold, that is, a data pulse is applied between the scan electrode 37 and the data electrode 44 to start the discharge, the above-mentioned data pulse is generated. Depending on the polarity of the positive and negative charges, positive and negative charges are attracted to the surfaces of the dielectrics on both sides, and the accumulation of charges occurs. Since the equivalent internal voltage, that is, the wall voltage, resulting from the accumulation of the electric charges has the opposite polarity to the voltage of the data pulse, the effective voltage inside the cell decreases as the discharge grows, and the voltage of the data pulse becomes a constant value. Even if it holds, the discharge cannot be continued and finally stops.

After that, when a sustain pulse having a pulse voltage of the same polarity as the wall voltage is applied between the adjacent scan electrode 37 and sustain electrode 40, the wall voltage is superposed as an effective voltage. Even if the voltage amplitude of the sustain pulse is lower than the voltage of the discharge threshold, the display cell can internally discharge beyond the threshold.

Therefore, the discharge can be maintained by continuously applying the sustain pulse between the scan electrode 37 and the sustain electrode 40. This function is the above-mentioned memory function. Further, the discharge can be stopped by applying an erase pulse, which is a low-voltage pulse voltage having a magnitude and a width that neutralizes the wall voltage, to the scan electrode or the sustain electrode.

A PD for dot matrix display in which display cells 34 are arranged in a matrix of j × k rows and columns.
Referring to FIG. 14 showing the configuration focusing on the electrode arrangement of P, the PDP 19 shown in this figure has scan electrodes Sc1, Sc2, ..., Scj and sustain electrodes Su arranged in parallel with each other.
, Suj, and data electrodes D1, D2, ... Dk arranged orthogonal to the scan electrodes and sustain electrodes.
With.

Here, if the phosphor 42 is separately coated into three colors of RGB, a PDP capable of color display can be obtained.

The above driving method will be described below. See JP-A-6-186927 for reference.

FIG. 16 is a time chart showing an example of the drive voltage waveforms described above. Corresponding to the PDP 19 shown in FIG. 17, a common sustain electrode drive pulse Wu applied to the sustain electrodes Su11, Su12, ..., Su4m is provided. And scan electrodes Sc11, Sc12, Sc1m, Sc21, Sc22,
Sc2m, Sc31, Sc32, Sc3m, Sc41,
Scan electrode drive pulses Ws11, Ws12, Ws1m, Ws21, Ws applied to Sc42 and Sc4m, respectively.
22, Ws2m, Ws31, Ws32, Ws3m, Ws
3m, Ws41, Ws42, Ws4m and data electrode D
Data pulse Wdi applied to i (1 ≦ i ≦ k) is shown.

The driving is temporally divided into three periods of a preliminary discharge period Tp, a writing discharge period Tw, and a sustain discharge period Ts, and the sustain electrode drive pulse Wu is a preliminary discharge pulse Vp.
And sustain pulse Vsu, and scan electrode drive pulse Ws
11, Ws12, Ws1m, Ws21, Ws22, Ws
2m, Ws31, Ws32, Ws3m, Ws3m, Ws
41, Ws42 and Ws4m are S in addition to the common preliminary discharge erase pulse Vp, sustain pulse Vss, erase pulse Ve.
Scan pulse Vw1 sequentially applied in the order of c11, Sc12, ...
1, Vw12, Vw1m, Vw21, Vw22, Vw2
m, Vw31, Vw32, Vw3m, Vw41, Vw4
2, Vw4m is included.

The preliminary discharge period Tp is a period for generating active particles for stably generating the writing discharge in the subsequent writing discharge period, and is forcibly applied by applying the preliminary discharge pulse Vp to all sustain electrodes. All the cells of the PDP are discharged, and the wall charges in the display cells are neutralized by the preliminary discharge erasing pulse Vpe, and the process ends.

To turn on the 1i-th display cell, the data pulse Vdi is made coincident with the timing of the scan pulse Vw11 to generate a discharge between the scan electrode Sc11 and the data electrode Di corresponding to the scan pulse Vw11. Let When this display cell is not turned on, the data pulse Vdi is not applied.

As described above, in the display cell which has been turned on once by applying the data pulse Vdi, the discharge is repeated between the scan electrode and the sustain electrode by the sustain pulse Vss and the sustain pulse Vsu after this timing and the lighting is continued. When the sustain erasing pulse Ve is applied to the scan electrodes, the discharge is stopped and the lights are turned off.

Since the sustain pulses Vss and Vsu are common to all the scan lines, a plurality of scan lines are generally integrated into one sustain pulse generating circuit. PDP
Is a relatively small scale and the load of the sustain pulses Vss and Vsu is small, the display area of the PDP is usually divided into several areas, and one sustain pulse generation circuit is provided for each of the divided areas. Is assigned.

A sustain pulse drive circuit 1 which divides the display area of the PDP into four and supplies sustain pulses corresponding to the respective areas.
Basic P with 4A-14D and 15A-15D
Referring to FIG. 15 showing an example of the DP drive circuit, the basic PDP drive circuit shown in this figure is similar to the sustain pulse drive circuit 14 in FIG.
In addition to A-14D and 15A-15D, PDP19 and P
The data drivers 11 and 12 for applying the data pulse Vdi to the respective data electrodes corresponding to the odd and even data lines of the DP 19, and the display data D input to the data clock C are divided into the odd and even data lines. The data distributor 20 for supplying the data Du and Dd to the data drivers 11 and 12, respectively, and the preliminary discharge pulse Vp, the preliminary discharge erase pulse Vpe and the sustain erase in response to the signal from the timing generator 21 based on the field signal. The preliminary discharge pulse driving circuit 23, the preliminary discharge erasing pulse driving circuit 22, and the sustain erasing pulse driving circuit 24 which respectively supply the pulse Ve, and the scan driver 13 which generates the scanning pulse in response to the field signal F and the scanning signal S.
And a mixer 16 for mixing sustain pulses, pre-discharge erasing pulses, sustain erasing pulses and scan pulses to generate scan electrode driving pulses, and a mixer 16 for mixing sustain pulses and pre-discharge pulses and generating sustain electrode driving pulses. And a container 17.

To explain the operation, the sustain discharge in the previous field is stopped by the field signal F, the preliminary discharge is performed, and the corresponding scan electrodes are sequentially driven at each timing of the scan signal S. The display data D is divided into data Du and Dd by the data distributor 20 and supplied to the data drivers 11 and 12, respectively. The data drivers 11 and 12 have data pulses V applied to the data electrodes corresponding to the odd-numbered and even-numbered data lines, respectively.
Apply di. The display cells on which the write discharge has been performed by this scanning repeat the sustain discharge by the subsequent sustain pulses Vsu and Vss.

[0019]

In such a PDP, for example, among the display cells driven by the pair of scan electrodes Sce and sustain electrodes Sue shown in FIG. There was a problem that the brightness was different. That is, when the number of lights in one row is small, the brightness of the lighted display cell is high, and conversely, when the number of lights in one row is high, the brightness of the lighted display cell is low.

Further, a PDP having a structure as shown in FIG.
, The sustain pulse drive circuits 14A, 15A
When the number of lit display cells in the area shared by the two is different, the sustain pulse waveform and amplitude applied to each display cell are different due to the output impedance of the sustain pulse drive circuits 14A and 15A or the impedance of the scan electrode and the sustain electrode of the PDP. Occurs, and the light emission output of the display cells in the above area, that is, the brightness varies depending on the number of lit display cells of the display cells in the area.

That is, the brightness is large when the number of lights in the area driven by the same drive circuit, the scan electrode, and the sustain electrode pair is small, and conversely, the brightness is small when the number of lights is large.

Therefore, the display of the correct luminance is not performed, and the crosstalk in the horizontal direction occurs. Further, in the case of multi-gradation color display, there is a problem that the gradation and chromaticity are not accurately reproduced and the display is remarkably deteriorated.

An object of the present invention is to solve the above-mentioned problems and to provide a PDP in which the variation in brightness due to the number of lit display cells is reduced.

[0024]

SUMMARY OF THE INVENTION A method of compensating for brightness in a plasma display according to the present invention is a scan electrode group consisting of a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane and sustaining discharge of the display cell. For driving a plasma display including at least a sustain electrode group including a plurality of sustain electrodes for data writing and a data electrode group including a plurality of data electrodes for writing data that is orthogonal to the scan electrode group and the sustain electrode group and is driven according to display data. In the method, a write discharge period for selecting a display cell and a sustain discharge period for sustaining light emission of the selected display cell are driven separately, and correction unit display rows for at least one set of scan electrodes and sustain electrodes are provided. The correction unit display line is detected by detecting the distribution of the display data and calculating by a predetermined luminance variation coefficient corresponding to the distribution of the display data. Obtaining the number of sustain discharges to obtain a desired brightness, the correction unit display each row, the number of sustain discharges, characterized in that the stop sustain discharge at the end of completion.

Alternatively, a scan electrode group consisting of a plurality of scan electrodes corresponding to the scan lines of the display cells formed on the same plane, and a sustain electrode group consisting of a plurality of sustain electrodes for sustaining the discharge of the display cells and the scan electrodes. In a method of driving a plasma display, which comprises at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which is driven according to display data, the writing discharge period for selecting a display cell and the selected discharge period. The display cells are driven separately by the sustain discharge period for sustaining light emission, and
The scan electrode group and the sustain electrode group are divided by a plurality of sustain pulse drive circuits to perform sustain discharge drive, and the distribution of the display data of the display cells driven by each sustain pulse drive circuit is detected and corresponding to the display data. The number of sustain discharges for obtaining the desired brightness is calculated for each sustain pulse drive circuit by calculating with a predetermined brightness variation coefficient, and the sustain discharge is stopped after the predetermined number of sustain discharges is completed for each sustain pulse drive circuit. It is characterized by

Alternatively, a scan electrode group including a plurality of scan electrodes corresponding to the scan lines of the display cells formed on the same plane, and a sustain electrode group including a plurality of sustain electrodes for sustaining the discharge of the display cells and the scan electrodes. In a method of driving a plasma display, which comprises at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which is driven according to display data, the writing discharge period for selecting a display cell and the selected discharge period. The display cells are driven separately from the sustain discharge period for sustaining light emission, and the scan electrode group and the sustain electrode group are divided by a plurality of sustain pulse drive circuits to perform sustain discharge drive, and each sustain pulse drive circuit drives them. The distribution of the display data of the display cells to be detected and the correction including at least one set of scan electrodes and sustain electrodes are performed. For each correction unit display line, the distribution of the display data for each display line is detected, and calculation is performed based on a predetermined luminance variation coefficient from the distribution of the display data for each sustain pulse drive circuit and each correction unit display line. The number of sustain discharges is calculated, and the sustain discharge is stopped after the predetermined number of sustain discharges is completed for each correction unit display row.

Alternatively, the sustain discharge is stopped by applying an erase pulse to the scan electrodes or the sustain electrodes.

Alternatively, the sustain discharge is stopped by applying an erasing pulse to the scan electrodes or the sustain electrodes, and all the sustain discharges in the display area of the sustain pulse drive circuit are stopped for each sustain pulse drive circuit. After that, the sustain pulse of the sustain pulse drive circuit is stopped.

Alternatively, the sustain discharge is stopped by stopping either or both of the sustain pulse to the scan electrode and the sustain pulse to the sustain electrode.

Alternatively, a sustaining pulse having the same phase as the sustaining pulse to the sustaining electrodes is applied to the scan electrodes, or a sustaining pulse having the same phase as the sustaining pulses to the scan electrodes is applied to the sustaining electrodes. It is characterized by being applied.

The plasma display apparatus of the present invention includes a scan electrode group formed of a plurality of scan electrodes corresponding to a scan line of a display cell formed on the same plane and a sustain electrode formed of a plurality of sustain electrodes for sustaining a discharge of the display cell. A plasma display comprising at least an electrode group and a data electrode group consisting of a plurality of data electrodes for writing data which are orthogonal to the scan electrode group and the sustain electrode group and driven according to display data, wherein at least one set of scan electrodes is provided. A detection circuit for detecting the distribution of display data for each correction unit display row, which comprises sustain electrodes, and a desired brightness for each correction unit display row calculated by a predetermined brightness variation coefficient corresponding to the display data distribution. An arithmetic circuit for obtaining the number of sustain discharges to obtain
An erase pulse drive circuit or a sustain pulse stop circuit having a function of stopping the sustain discharge after the number of sustain discharges is completed for each correction unit display row based on the number of sustain discharges obtained by the arithmetic circuit. Is characterized by.

Alternatively, a scan electrode group consisting of a plurality of scan electrodes corresponding to the scan lines of the display cells formed on the same plane, and a sustain electrode group consisting of a plurality of sustain electrodes for sustaining the discharge of the display cells and the scan electrodes. A plasma display including at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data and are orthogonal to each other. A plurality of sustain pulse drive circuits for driving, and a detection circuit for detecting a distribution of display data of display cells driven by each sustain pulse drive circuit,
An arithmetic circuit that calculates the number of sustain discharges to obtain a desired luminance for each sustain pulse drive circuit by operating with a predetermined luminance variation coefficient corresponding to display data, and based on the number of sustain discharges obtained by the arithmetic circuit An erase pulse drive circuit or a sustain pulse stop circuit having a function of stopping the sustain discharge after a predetermined number of sustain discharges is completed for each sustain pulse drive circuit.

Alternatively, a scan electrode group consisting of a plurality of scan electrodes corresponding to the scan lines of the display cells formed on the same plane, and a sustain electrode group consisting of a plurality of sustain electrodes for sustaining the discharge of the display cells and the scan electrodes. A plasma display including at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data and are orthogonal to each other. A plurality of sustain pulse drive circuits to be driven, a first detection circuit for detecting a distribution of display data of display cells driven by each sustain pulse drive circuit, and a correction including at least one set of scan electrodes and sustain electrodes A second detection circuit that detects the distribution of display data for each unit display row, and a table for each sustain pulse drive circuit and each correction unit display row. An arithmetic circuit that calculates the number of sustain discharges for each correction unit display row by calculating based on a predetermined luminance variation coefficient from the distribution of data, and for each correction unit display row based on the number of sustain discharges calculated by the arithmetic circuit An erase pulse drive circuit or a sustain pulse stop circuit having a function of stopping the sustain discharge after the predetermined number of sustain discharges is completed.

[0034]

Embodiments of the present invention will now be described with reference to the drawings. Referring to FIG. 1, which is a block diagram showing a circuit of a first embodiment of a brightness compensating circuit for realizing a plasma display of the present invention, the brightness compensating circuit of the present embodiment is arranged so that the display data D for each of the scanning electrodes 1 to j is displayed. Counter 1 for counting numbers
And a memory 4 for storing the count value D11 of the counter 1,
Counter 2 that counts the number of scans, counter 3 that calculates the number of sustains, count value S11 of counter 2 and counter 3
A selector 5 for selecting any one of the count values S12 of the above, a memory 6 for storing timing data for stopping the sustain discharge,
It is provided with a comparator 7 which compares the output data MD1 to j of the memory 6 with the measurement value S12 of the counter 3 and outputs the maintenance stop signals SD1 to j.

Referring to FIG. 2 which is a block diagram showing the configuration of the driving circuit of the PDP having the brightness compensation circuit of the present embodiment,
The PDP 9 shown in FIG. 14 and the data drivers 11 and 12
And a sustain pulse drive circuit 15 for supplying a sustain pulse,
The data distributor 20, the scan driver 13, the timing generator 21, the sustaining erase pulse drive circuit 24, the preliminary discharge pulse drive circuit 23, the preliminary discharge erase pulse drive circuit 22, and the sustain pulse and the preliminary discharge pulse are mixed. In addition to the mixer 17 for generating the sustain electrode driving pulse and the mixer 16 for mixing the sustain pulse, the scan pulse and the sustain erasing pulse to generate and supply the scan electrode driving pulse, respectively, a brightness compensation circuit 18; A sustain driver 1 which receives sustain stop signals SD1 to j from the brightness compensation circuit 18 and generates sustain pulses.
4 and.

The operation will be described with reference to FIGS. 1 and 2 and FIG. 3 showing the driving time chart of the driving circuit of this embodiment. The counter 1 is reset in response to the supply of the field signal F and the scanning signal S, and scanning is performed. The number of display data D for each line is counted and a count value D11 is output. Counter 2
Counts the scanning signal S and supplies the signal S11 to the selector 7. The counter 3 is reset in response to the sustain start signal SS, counts the sustain cycle signal SP, and supplies the count value S12 to the selector 5 and the comparator 7. Selector 5 is signal S1
1 or the signal S12 is selected and the address designating signal A1 is supplied to the memory 4 and the memory 6. As for the selection, the count value S11 is selected in the write discharge period Tw in which the display data is supplied and the data pulse Vdi is output, and the count value S12 is selected in the sustain discharge period Ts. In the writing discharge period Tw, the count value D11 is stored in the memory 4 as data for each scanning line, with its storage position designated according to the address designating signal A1. In the sustain discharge period Ts, the display data number of all scan lines is read from the memory 4 as the signal D12 in each sustain cycle and supplied to the memory 6. The memory 6 stores data indicating the number of sustain discharges for obtaining a desired luminance in consideration of the relationship of the rate of luminance change depending on the number of display data, and is instructed by the signal D12 to instruct the number of sustain discharges. The signals MD1 to j are supplied to the comparator 7. The comparator 7 outputs the signal M
D1-j and signal S12 are compared, and when the number of sustain discharges instructed by signals MD1-j is reached, sustain stop signals SD1--
j is output and supplied to the sustain driver 14.

Referring to FIG. 3, the sustain discharge is interrupted when the sustain pulse of each scan line is stopped. After that, the common sustain erasing pulse Ve is applied to all the scanning lines, and the process ends. As described above, since the number of sustain discharges is independently controlled for each scanning line and the luminance compensation is performed, accurate luminance compensation can be performed on the entire display surface, and a good display state can be realized. By the way, in the present embodiment, the sustain discharge pulse was applied 400 times in one frame time when all the display cells of the corresponding scan line were turned on, but when the number of the lighted cells was 50%, the sustain discharge pulse was turned on 370 times. Cell is 10%
In this case, the pulse was applied 300 times.

In this embodiment, the correction unit display line is one line at a time, but it is also possible to collectively control two or more lines as a correction unit display line. In this case, the control circuit can be slightly simplified. In particular, in a PDP having a large display capacity, a substantial improvement in the display state can be realized even if the correction unit display lines are appropriately plural. The plurality of correction unit display lines can be applied to all the examples described later.

Further, it is not always necessary to detect the display data for all the display cells. Depending on the application, the display data of discrete display cells such as every other cell may be detected and controlled to simplify the detection circuit. You may plan. Such a method can also be applied in the examples described below.

Further, the correction unit display lines for detecting the display data may be set discretely, and the interpolated values from the upper and lower display data may be applied to the lines between them to further simplify the circuit. This method can also be applied to the examples described below.

Next, a second embodiment of the present invention will be described. Referring to FIG. 4, which is a block diagram showing the circuit of the second embodiment of the brightness compensation circuit for realizing the plasma display of the present invention, the brightness compensation circuit of the present embodiment has a sustain discharge as compared with the first embodiment. 4 instead of the memory 6 for storing the timing data for stopping the scanning
The memory 10 stores timing data corresponding to the suspension of the sustain discharge for each of the divided instruction blocks A to D.

Referring to FIG. 4 which is a block diagram showing the configuration of the driving circuit of the PDP including the brightness compensation circuit of the present embodiment,
A PDP 19 similar to the basic PDP drive circuit shown in FIG.
, The data drivers 11 and 12, and the display area of the PDP 19 are divided into four areas, that is, the sustain blocks A.
To sustain pulse drive circuit 1 for supplying sustain pulses corresponding to D
4A to 14D, 15A to 15D and the data distributor 20
A scan driver 13, a timing generator 21, a sustaining erase pulse drive circuit 24, a preliminary discharge pulse drive circuit 23, a preliminary discharge erase pulse drive circuit 22, a sustain pulse and a preliminary discharge pulse, and each sustain electrode. A mixer 17 for generating a drive pulse and a sustain pulse, a scan pulse and a sustain erase pulse are mixed to generate a scan electrode drive pulse.
In addition to the mixer 16 for supplying, a brightness compensation circuit 18;
Sustain drivers 14A-D for receiving sustain stop signals SD1-4 from brightness compensation circuit 18 and generating sustain pulses.

The operation will be described with reference to FIGS. 4 and 5 and FIG. 6 which is a drive time chart of the drive circuit of the present embodiment. In order to avoid redundant description, the difference from the first embodiment will be described. The memory 10 sets a desired brightness in consideration of the relationship of the ratio of the brightness variation depending on the number of display data of blocks in each sustain pulse drive circuit. Data indicating the number of sustain discharges for obtaining is stored, and signals MD1 to 4 indicating the number of sustain discharges are supplied to the comparators 7A to D in response to the signal D12. The comparators 7A to 7D output the signal MD
1 to 4 and the signal S12 are compared, and when the number of sustain discharges instructed by the signals MD1 to 4 is reached, the sustain stop signals SD1 to SD4
Is output and supplied to the sustain drivers 14A to 14D.

Referring to FIG. 6, the sustain discharge for each sustain pulse driving circuit is interrupted when the sustain pulse is stopped, and then the common sustain erasing pulse Ve is applied to all the scan lines to end.

In this method, brightness compensation is performed for each sustain pulse drive circuit according to the number of display data, and although the compensation accuracy is relatively coarse, control such as sustain discharge stop can be easily performed.

Next, a third embodiment of the present invention will be described. Referring to FIG. 7, which is a block diagram showing a circuit of a third embodiment of a brightness compensation circuit for realizing the plasma display of the present invention, the brightness compensation circuit of the present embodiment counts the number of display data D for each scanning line. Counter 25, a memory 27 that stores the count value D21 of the counter 25, a counter 25 that counts the number of display data supplied to each of the sustain blocks A to D, and a memory 28 that stores the count value of the counter 25. A counter 2 for counting the number of scans, a counter 3 for counting the number of sustains, and a count value S2 of the counter 2.
1 or the count value S22 of the counter 3, a memory 29 for storing the timing data of the sustain discharge stop, the output data of the memory 29 and the counter 3.
And a comparator 30 that outputs a maintenance stop signal by comparing the count value S22.

Referring to FIG. 8 which is a block diagram showing the configuration of the drive circuit of the PDP including the brightness compensation circuit of the present embodiment,
A PDP 19 similar to the basic PDP drive circuit shown in FIG.
, The data drivers 11 and 12, and the display area of the PDP 19 are divided into four areas, that is, the sustain blocks A.
To sustain pulse drive circuit 1 for supplying sustain pulses corresponding to D
4A to 14D, 15A to 15D and the data distributor 20
A scan driver 13, a timing generator 21, a preliminary discharge pulse drive circuit 23, a preliminary discharge erase pulse drive circuit 22, and a mixer 17 for mixing sustain pulses and preliminary discharge pulses to generate sustain electrode drive pulses. In addition to the above, the brightness compensating circuit 31, the erase driver 32 for generating the sustain erasing pulse upon receiving the sustain stop signal ED from the brightness compensating circuit 31, the sustain pulse, the scan pulse, and the sustain erasing pulse are mixed, and each scan electrode is driven. And a mixer 16 for generating and supplying pulses.

The operation will be described with reference to FIGS. 7 and 8 and FIG. 9 showing the driving time chart of the driving circuit of the present embodiment. The counter 25 is reset in response to the scanning signal S and the display data D for each scanning line. Is counted by the clock C synchronized with the display data, and the count value D21 is output.
The counter 26 is reset in response to the supply of the field signal F and each of the sustain pulse drive circuits 14A to 14D, 1.
The display data supplied for each divided block of 5A to 15D is counted based on the count value D21 for each scanning line, and the count value D
22 is output. Here, since the PDP display area is divided into four sustain blocks A to D as described above, the number of scan lines corresponding to the shared blocks of each pair of sustain pulse drive circuits 14A to 14D and 15A to 15D, that is, the number of block lines. Is 1/4 of the total number of scanning lines. Counter 2
Supplies the signal S21 to the counter 25 and the selector 5 for counting the scanning signal S and dividing the scanning signal S by the number of block lines. The counter 3 is reset in response to the sustain start signal SS, counts the sustain period signal SP, and supplies the count value S22 to the selector 5 and the comparator 30. The selector 5 selects either the signal S21 or the signal S22 and selects the memory 2
7 and the memory 28 are supplied with the address instruction signal A2.
The selection is such that the display data is supplied and the data pulse Vd
In the writing discharge period Tw for outputting i, the count value S
21 is selected and the count value S2 during the sustain discharge period Ts.
Select 2. In the write discharge period Tw, the count value D21 is stored in the memory 27 as the data for each scan line by designating the storage position according to the address designating signal A2, and the count value D22 is also stored as the data for each sustain block in accordance with the address designating signal A2. The position is designated and stored in the memory 28. In the sustain discharge period Ts, the number of display data of all scanning lines is read out as a signal D23 from the memory 27 and the number of display data of all blocks is read out from the memory 28 as a signal D24 and supplied to the memory 29 in each sustain cycle. The memory 29 stores data indicating the number of sustain discharges to obtain a desired luminance in consideration of the relationship between the number of display data per sustain block and the ratio of luminance variation depending on the number of display data per scan line.
And a signal MD instructing the number of sustain discharges in response to the signal D24. The comparator 30 compares the signal MD and the signal S22, and outputs the sustain stop signal ED when the number of sustain discharges instructed by the signal MD is reached,
The erase driver 32 is supplied.

Referring to FIG. 9, the conventional P shown in FIG.
Instead of the sustain erase pulse Ve indicating the end of the sustain discharge period Ts in the time chart of the DP drive circuit, Ws11, Ws12, Ws1 indicating the drive waveform of each scan electrode.
m, Ws21, Ws22, Ws2m, Ws31, Ws3
2, Ws3m, Ws3m, Ws41, Ws42, Ws4
sustain erase pulses Ve11, Ve12, Ve1m, Ve21, Ve applied to m at independent timings.
22, Ve2m, Ve31, Ve32, Ve3m, Ve
41, Ve42 and Ve4m are shown. Since the sustain discharge of each scan line is stopped when these sustain erase pulses are applied, the number of sustain discharges is independently controlled for each scan line to perform brightness compensation. Further, since the timings of these sustaining and erasing pulses are calculated in consideration of the number of display data for each block, if the number of display data of the belonging block is different even if the number of display data on one scanning line is the same, Sustain erase pulses are applied at different timings.

The sustain erasing pulse in FIG. 9 described above has been described by taking a narrow pulse as an example, but it is an erasing pulse that forms a relatively narrow pulse with a phase slightly shifted from a sustain pulse of a wide pulse or an opposing electrode. It may be.

Next, a fourth embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of a PDP drive circuit according to a fourth embodiment for realizing the plasma display of the present invention.
Referring to 0, the PDP 19, the data driver 11,
12, scan driver 13, and sustain pulse drive circuit 14
A to 14D, 15A to 15D, a data distributor 20, and
The mixers 16 and 17, the brightness compensation circuit 31, the timing generator 21, the preliminary discharge erase pulse drive circuit 22, the preliminary discharge pulse drive circuit 23, the sustain erase pulse drive circuit 24, and the luminance instead of the erase driver. The compensation circuit 31 includes a sustain stop signal ED and a sustain pulse stop circuit 33 that receives the sustain pulse and stops the sustain pulse supplied to the PDP 19 in response to the sustain stop signal ED.

The operation will be described with reference to FIG. 10 and FIG. 11 showing the drive time chart of the drive circuit of the present embodiment. The erase data ED output from the brightness compensation circuit 31 is supplied to the sustain pulse stop circuit 33 and maintained. The pulse stop circuit 33 supplies the sustain pulse to the mixer 16, but when the sustain stop signal is instructed by the sustain stop signal ED, the sustain pulse supply thereafter is stopped for each scanning line. Looking at the sustain discharge period Ts in FIG. 11, each scan electrode drive waveform Ws1
1, Ws12, Ws1m, Ws21, Ws22, Ws2
m, Ws31, Ws32, Ws3m, Ws3m, Ws4
In 1, Ws42, and Ws4m, the sustain pulse stops at independent timings, and the common sustain erase pulse Ve is applied to all scan lines by the sustain erase pulse drive circuit to end the sustain discharge period Ts. As described above, the number of sustain discharges of each scan line is independently controlled to perform brightness compensation.

Next, a fifth embodiment of the present invention will be described. A block diagram showing the configuration of the PDP drive circuit can be realized by the same configuration as that of FIG. 10 shown in the fourth embodiment, so that it will be omitted. However, referring to FIG. 12 showing a drive time chart of the drive circuit of the present embodiment, Each scan electrode drive waveform Ws11, Ws12, Ws1m, Ws in the sustain discharge period Ts
21, Ws22, Ws2m, Ws31, Ws32, Ws
At 3m, Ws41, Ws42, and Ws4m, the state in which the sustain pulse voltage is applied is started at each independent timing, and the state is maintained until just before the final sustain pulse of the sustain electrode drive waveform Wu. The sustain discharge period Ts ends when the sustain erase pulse Ve common to all scan lines is applied. While the sustain pulse voltage is still applied to the scan electrodes, the sustain discharge does not occur because the potential inversion between the scan electrodes and the sustain electrodes does not occur even if the sustain pulse is repeatedly applied in the sustain electrode drive waveform Wu. Stop. As described above, the number of sustain discharges of each scan line is independently controlled to perform brightness compensation. In this method, the same effect can be obtained by repeatedly applying the sustain pulse having the same phase as the sustain pulse Vsu of the sustain electrode drive waveform Wu to the scan electrodes during the sustain discharge stop period.

Although several embodiments have been described above, the present invention is not limited to a three-electrode structure as long as it has a parallel sustain discharge electrode structure, and a monochromatic display PDP using gas emission is also used. The same is also effective for a color PDP having a phosphor layer.

Further, even when one field is divided into a plurality of subfields and the number of sustain discharges in each subfield is weighted to perform multi-gradation display, data for instructing the sustain stop timing depending on the number of display data is provided. Of course, if the memory to store is prepared for each subfield, all the above-mentioned luminance compensation methods can be applied. Further, in this case, the brightness compensation may be applied only to the upper subfield that has a large effective effect to simplify the subfield.

[0056]

As described above, the plasma display of the present invention can reduce the difference in brightness between scan lines and sustain blocks and display the entire display screen with uniform brightness.
There is an effect that crosstalk can be prevented and a display with good halftone and chromaticity can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a brightness compensation circuit in a plasma display of the present invention.

FIG. 2 is a block diagram of a PDP drive circuit including the brightness compensation circuit of this embodiment.

FIG. 3 is a time chart showing an example of an operation in this embodiment.

FIG. 4 is a block diagram showing a second embodiment of the brightness compensation circuit in the plasma display of the present invention.

FIG. 5 is a block diagram of a PDP drive circuit including the brightness compensation circuit of this embodiment.

FIG. 6 is a time chart showing an example of operation in the present embodiment.

FIG. 7 is a block diagram showing a third embodiment of the brightness compensation circuit in the plasma display of the present invention.

FIG. 8 is a block diagram of a PDP drive circuit including the brightness compensation circuit of the present embodiment.

FIG. 9 is a time chart showing an example of operation in the present embodiment.

FIG. 10 is a block diagram of a PDP circuit of a fourth embodiment including a brightness compensation circuit in the plasma display of the present invention.

FIG. 11 is a time chart showing an example of operation in the present embodiment.

FIG. 12 is a time chart showing the operation of the fifth embodiment of this embodiment.

FIG. 13 is a cross-sectional view showing the configuration of one display cell of an AC memory type PDP.

FIG. 14 is a plan view showing an electrode arrangement of an AC memory type PDP.

FIG. 15 is a block diagram showing an example of a drive circuit of an AC memory type PDP.

FIG. 16 is a time chart showing an example of a drive voltage waveform of an AC memory type PDP.

FIG. 17 is a plan view showing an electrode arrangement of an AC memory type PDP.

[Explanation of symbols]

1, 2, 3, 25, 26 Counter 7, 7A to 7D, 30 Comparator 4, 6, 10, 27, 28, 29 Memory 5 Selector 11, 12 Data driver 13 Scan driver 14A to 14D, 15A to 15D Sustain pulse Generation circuit 16,17 Mixer 8,18,31 Luminance compensation circuit 9,19 PDP 20 Data distributor 21 Timing generator 22 Priming erase pulse drive circuit 23 Priming pulse drive circuit 24 Sustain erase pulse drive circuit 32 Erase driver 33 Sustain pulse Stop circuit 34 Display cell 35 Partition wall 36,43 Dielectric 37 Scan electrode 38 Discharge gas space 39,45 Insulating substrate 40 Sustaining electrode 41 Protective film 42 Phosphor 44 Data electrode Sc1, Sc2, ..., Scj, Sc11, Sc12,
..., Sc4m scan electrodes Su1, Su2, ..., Suj, Su11, Su12,
…, Su4m sustain electrodes D1, D2,…, Dk data electrodes

Claims (10)

[Claims] 1. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. In a method of driving a plasma display, which comprises at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data, a writing discharge period for selecting a display cell and the selected The sustain discharge period for sustaining light emission of the display cells is driven separately, and the distribution of the display data for each correction unit display row composed of at least one set of scan electrodes and sustain electrodes is detected. Then, the number of sustain discharges for obtaining the desired luminance is calculated for each correction unit display row by calculating with a predetermined luminance variation coefficient, and the correction unit table is obtained. A brightness compensating method for a plasma display, which comprises stopping the sustain discharge after the number of times of the sustain discharge is completed for each row. 2. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. In a method of driving a plasma display, which comprises at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data, a writing discharge period for selecting a display cell and the selected The sustain discharge period for sustaining light emission of the display cell is separated and driven,
In addition, the scan electrode group and the sustain electrode group are divided by a plurality of sustain pulse drive circuits to drive the sustain discharge, and the distribution of the display data of the display cells driven by each sustain pulse drive circuit is detected to correspond to the display data. Then, the number of sustain discharges to obtain a desired brightness is calculated for each sustain pulse drive circuit by calculating with a predetermined brightness variation coefficient,
A brightness compensating method for a plasma display, characterized in that the sustain discharge is stopped after a predetermined number of sustain discharges is completed for each sustain pulse drive circuit. 3. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. In a method of driving a plasma display, which comprises at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data, a writing discharge period for selecting a display cell and the selected The sustain discharge period for sustaining light emission of the display cell is separated and driven,
Further, the scan electrode group and the sustain electrode group are divided by a plurality of sustain pulse drive circuits to drive the sustain discharge, and the distribution of the display data of the display cells driven by the respective sustain pulse drive circuits is detected. Detecting a distribution of display data for each correction unit display row composed of at least one set of sustain electrodes, and determining a predetermined luminance variation coefficient from the distribution of the display data for each sustain pulse drive circuit and each correction unit display row. A brightness compensation method for a plasma display, characterized in that the number of sustain discharges for each correction unit display row is calculated based on the calculation, and the sustain discharge is stopped after a predetermined number of sustain discharges for each correction unit display row. 4. The brightness compensation method for a plasma display according to claim 1, wherein the sustain discharge is stopped by applying an erase pulse to the scan electrodes or the sustain electrodes. . 5. A sustain discharge is stopped by applying an erasing pulse to the scan electrodes or the sustain electrodes, and all the sustain discharges in the display area of the sustain pulse drive circuit are stopped for each sustain pulse drive circuit. The brightness compensation method for a plasma display according to claim 1, 2, or 3, wherein the sustain pulse of the sustain pulse drive circuit is stopped after that. 6. Sustaining the sustaining discharge by using either a sustaining pulse to the scan electrode or a sustaining pulse to the sustain electrode, or
The brightness compensation method for a plasma display according to claim 1, 2 or 3, wherein both are stopped. 7. A sustain pulse having the same phase as the sustain pulse to the sustain electrode is applied to the scan electrode, or a sustain pulse having the same phase as the sustain pulse to the scan electrode is applied to the sustain electrode. The brightness compensation method for a plasma display according to claim 1, 2 or 3, wherein the method is performed by applying the voltage. 8. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. A plasma display having at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data which are driven according to display data and are orthogonal to each other. A detection circuit for detecting the distribution of display data for each unit display row, and a sustain discharge for obtaining a desired brightness for each correction unit display row by calculating with a predetermined brightness variation coefficient corresponding to the distribution of display data. Based on the arithmetic circuit for obtaining the number of times and the number of sustain discharges obtained by the arithmetic circuit, for each correction unit display row, after the number of sustain discharges is finished, the sustain discharge is finished. A plasma display apparatus, wherein a and a erase pulse drive circuit or sustain pulse stop circuits has a function to stop. 9. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. A plasma display having at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data, which are driven according to display data and are orthogonal to each other. A plurality of sustain pulse drive circuits to be driven, a detection circuit to detect the distribution of the display data of the display cells driven by each sustain pulse drive circuit, and an operation based on a predetermined luminance variation coefficient corresponding to the display data. Based on the number of sustain discharges obtained by the arithmetic circuit, an arithmetic circuit for obtaining the number of sustain discharges for obtaining a desired luminance for each sustain pulse drive circuit. A plasma display device comprising: an erase pulse drive circuit or a sustain pulse stop circuit having a function of stopping the sustain discharge after a predetermined number of sustain discharges is completed for each sustain pulse drive circuit. 10. A scan electrode group including a plurality of scan electrodes corresponding to scan lines of a display cell formed on the same plane, a sustain electrode group including a plurality of sustain electrodes for sustaining a discharge of the display cell, and the scan electrode. A plasma display having at least a group of electrodes and a group of sustain electrodes, and a data electrode group composed of a plurality of data electrodes for writing data, which are driven according to display data and are orthogonal to each other. A plurality of sustain pulse drive circuits to be driven, a first detection circuit for detecting a distribution of display data of display cells driven by each sustain pulse drive circuit, and a correction including at least one set of scan electrodes and sustain electrodes A second detection circuit that detects the distribution of display data for each unit display row, and display data for each sustain pulse drive circuit and each correction unit display row. Calculation circuit for calculating the number of sustain discharges for each correction unit display row by performing a calculation based on a predetermined luminance variation coefficient from the distribution of data, and for each correction unit display row based on the number of sustain discharges calculated by the calculation circuit. A plasma display device, comprising: an erase pulse drive circuit or a sustain pulse stop circuit having a function of stopping the sustain discharge after a predetermined number of sustain discharges.