JP4914576B2 - Plasma display device and driving method used for the plasma display device - Google Patents

Description

  The present invention relates to a plasma display device and a driving method used for the plasma display device, and more particularly to a plasma display device suitable for improving the image quality of black display and the driving method used for the plasma display device.

  A plasma display device that includes a plasma display panel (hereinafter also referred to as “PDP”) as its main part is thin and relatively easy to display on a large screen, has a wide viewing angle, and has a high response speed. , Has many features. For this reason, in recent years, it has been widely used as a flat panel display in a wall-mounted television, a public display device, and the like. This plasma display device has a DC discharge type (DC type) in which an electrode is exposed to a discharge space (discharge gas) and operated in a DC discharge state, and an electrode covered with a dielectric layer, depending on the operation method. Is classified into an AC discharge type (AC type) which is not directly exposed but operated in an AC discharge state. In the DC type, discharge is generated during a period in which the voltage is applied, and in the AC type, the discharge is sustained by reversing the polarity of the voltage. Here, the structure and driving method of a plasma display device using a conventional three-electrode AC type PDP which is currently commercialized will be described.

  Conventionally, this type of plasma display device includes a display panel (PDP) 1, a data driver 11, a scan driver 12, a sustain driver 13, a charge recovery circuit 14, a power supply circuit, as shown in FIG. 15, a signal processing circuit 21, and a control circuit 22. The PDP 1 has a front substrate and a rear substrate (not shown) arranged to face each other. On the surface of the front substrate facing the back substrate, the scan electrodes 2 and the sustain electrodes 3 are arranged in parallel to each other with a discharge gap (not shown). A scan pulse for performing address discharge is sequentially applied to the scan electrode 2. The scan electrode 2 and the sustain electrode 3 constitute a surface discharge electrode pair, and a sustain pulse is applied to generate a sustain discharge. A plurality of data electrodes 4 are provided on the surface of the rear substrate facing the front substrate so as to intersect with each of the surface discharge electrode pairs, and a display data pulse and an erase data pulse are applied to the data electrode 4. . A unit cell 5 is formed in each intersection region of the surface discharge electrode pair and the data electrode 4.

  The data driver 11 applies a display data pulse and an erase data pulse corresponding to the display data z to the data electrode 4. The scan driver 12 applies a scan pulse and an erase pulse to the scan electrode 2. The sustain driver 13 applies a sustain pulse to the sustain electrode 3. Under the control of the control circuit 22, the charge recovery circuit 14 recovers the charge of the capacitive component of the PDP 1 and sets the potentials of the scan electrode 2 and the sustain electrode 3 of the PDP 1.

  The power supply circuit 15 supplies a predetermined high-voltage power supply to the data driver 11, the scan driver 12, the sustain driver 13, and the charge recovery circuit 14. The signal processing circuit 21 includes an A / D (analog / digital) conversion circuit, a pixel conversion circuit, a subfield conversion circuit, and the like (not shown). The analog video signal in is converted into a digital video signal by the A / D conversion circuit. And converting the number of pixels of the video signal into the number of pixels corresponding to PDP1 by the pixel conversion circuit to generate a video signal, and the video signal from the pixel conversion circuit is subfielded by the subfield conversion circuit Each display data is converted to z and sent to the data driver 11. The control circuit 22 controls the operation timing of the data driver 11, the scan driver 12, the sustain driver 13, and the charge recovery circuit 14, and controls the input of the voltage generated by the power supply circuit 15. Timing signals (horizontal synchronization signal, vertical synchronization signal) H and V are input to the signal processing circuit 21 and the control circuit 22 to synchronize their operations with the display screen.

FIG. 2 is a configuration diagram showing a main part of the PDP 1 in FIG.
In this PDP 1, as shown in FIG. 2, n scanning electrodes 2 (Scani, i = 1, 2,..., N) arranged in parallel to each other in the row direction H on the inner surface of a front substrate (not shown) are maintained. A surface discharge electrode group composed of electrodes 3 (Susi, i = 1, 2,..., N) and an inner surface of a back substrate (not shown) are arranged along the column direction V so as to be orthogonal to the same surface discharge electrode group. In addition, m data electrodes 4 (Dj, j = 1, 2,..., M) are arranged. One unit cell 5 is formed in each of the intersecting regions of the surface discharge electrode group and the data electrode 4, and the cell group is arranged in a matrix in the row direction H and the column direction V. In the case of monochrome display, one pixel is constituted by one cell, and in the case of color display, one pixel is constituted by three cells (light emitting cells of red R, green G and blue B).

FIG. 3 is a cross-sectional view of the unit cell 5 in FIG.
In the unit cell 5, as shown in FIG. 3, a front substrate 21 and a rear substrate 22 are arranged to face each other with a predetermined interval. The front substrate 21 is composed of a glass substrate or the like, and the scan electrode 2 and the sustain electrode 3 are arranged on the front substrate 21 with a discharge gap 23 therebetween. These scan electrode 2 and sustain electrode 3 form a surface discharge electrode pair 6. Further, on the scan electrode 2 and the sustain electrode 3, metal trace electrodes (not shown) for reducing the wiring resistance are respectively laminated. Further, a transparent dielectric layer 24 is formed on these electrodes, and a protective layer 25 is formed on the transparent dielectric layer 24. The protective layer 25 is made of MgO or the like, and protects the transparent dielectric layer 24 from discharge. On the other hand, the back substrate 22 is formed of a glass substrate or the like, and the data electrodes 4 are provided on the back substrate 22 so as to be orthogonal to the scan electrodes 2 and the sustain electrodes 3. Further, a white dielectric layer 26 is provided on the data electrode 4, and a phosphor layer 27 is provided on the white dielectric layer 26. Between the front substrate 21 and the rear substrate 22, a grid-like partition wall 28 is formed so as to surround each unit cell 5. The partition wall 28 serves to secure the discharge space 29 and partition the pixels. In the discharge space 29, a mixed gas such as He, Ne, and Xe is sealed as a discharge gas.

FIG. 4 is a diagram for explaining the principle of the gradation display method using the scan sustaining separation driving system used in the PDP of FIG. 2, wherein the horizontal axis represents time, and the vertical axis represents the scan electrode numbers (1,... , N).
The scan sustaining separation driving method is a mainstream method currently used for driving a PDP. In this PDP, as shown in FIG. 4, six fields in which one field TF is weighted based on the gradation level are used. The subfields are divided into subfields 1SF, 2SF,..., 6SF, and each subfield is divided into an initialization period (also referred to as “preliminary discharge period”) T1, a scanning period T2, and a sustain period T3. The oblique lines in each scanning period T2 represent the timing of scanning pulses applied to each scanning electrode 2 in a line sequential manner. When both the scanning pulse and the display data pulse applied to the data electrode 4 are simultaneously applied, an address discharge is generated. The sustain period T3 is a period during which the unit cell 5 emits display light.

  In sustain period T3, sustain pulses are alternately applied to scan electrode 2 and sustain electrode 3, and the cells in which discharge occurred in scan period T2 correspond to the length of sustain period T3 (that is, the number of sustain pulses). Emits light with intensity. In FIG. 4, since the length of each sustain period T3 of subfields 1SF, 2SF,..., 6SF is set to a ratio of 1: 2: 4: 8: 16: 32, light emission in these sustain periods T3. By combining these, a screen with 64 gradations (0 to 63) is displayed. For example, when a 29-gradation screen is displayed, subfield 1SF (gradation; 1), subfield 3SF (gradation; 4), subfield 4SF (gradation; 8), during the period of 1 field TF, The subfield 5SF (gradation; 16) is controlled to emit light.

FIG. 5 is a diagram showing a main part of a driving waveform used in the scan maintenance separation driving method, and FIG. 6 is a schematic diagram showing a state of wall charges in the unit cell 5 at each timing.
With reference to these drawings, a driving method based on the scan maintenance separation driving method will be described.
As shown in FIG. 5, the sustain electrode 3 is applied with the voltage indicated by the waveform Sus, and the scan electrode 2 is sequentially applied with the voltages indicated by the waveforms Scan1,..., Scann. Further, a voltage indicated by the waveform Data is applied to the data electrode 4. Before the initialization period T1, there is a sustain period of a previous subfield (not shown), and whether or not sustain discharge is performed there, discharge is performed on the dielectric layer on each electrode in the unit cell 5 by discharge. The amount of wall charge that is accumulated charge is different. If the next address is performed as it is, the address discharge may be difficult to be performed due to the influence of the different wall charges, or the address may be erroneously performed. In the initialization period T1, wall charges generated on the dielectric layers in the unit cells 5 depending on the lighting state in the sustain period of the previous subfield are initialized (reset).

  As shown in FIG. 5, initialization is mainly performed in the sustain erasing period T11 in the initialization period T1. In the sustain erasure period T11, the sustain erasure waveform b is applied to the scan electrode 2 only when a sustain discharge occurs in the sustain period of the previous subfield, and between the scan electrode 2 and the sustain electrode 3 and between the scan electrode 2 and the data. A weak discharge occurs between the electrodes 4. In this weak discharge, a weak discharge is continuously generated by a ramp waveform whose voltage gradually changes, and a change in wall charge on the electrode due to the discharge is also small, and a strong discharge is generated at once by applying a rectangular wave. This is different from the discharge in which the polarity of the wall charge on the electrode is reversed at once. Thereby, the wall charge arrangement shown in FIG. 6A at the end of the sustain period of the previous subfield becomes the wall charge arrangement shown in FIG. 6B.

  Further, in the priming period T12 in the initialization period T1, a priming effect is generated for facilitating discharge when data is written line-sequentially based on display data, and the wall charge state is optimal for address discharge. It becomes a state. The priming period T12 includes a first priming period T13 and a second priming period T14. In the priming period T12, a priming waveform c and a priming erasing waveform d are applied to the scan electrode 2, and the priming waveform c generates a weak discharge regardless of the occurrence of the sustain discharge in the previous subfield. By generating in the discharge space 29, the address discharge is likely to occur. Therefore, in the priming period T12, the potential of the scan electrode 2 gradually increases in the positive direction with respect to the potential of the data electrode 3, and the negative wall charge increases in the scan electrode and the positive wall charge increases in the data electrode 3, respectively. To do. The generation of the priming particles and the increase in the wall charges work in the direction in which the address discharge is likely to occur. In particular, when the non-lighting display continues for a long time in the unit cell 5, the priming particles and the wall charges decrease. It tends to make up for these.

  On the other hand, in the second priming period T14, the wall charge amount on each electrode formed as shown in FIG. 6C in the first priming period T13 is adjusted so that proper driving can be performed, and FIG. The wall charge arrangement is as shown in d). Even in the second priming period T14, weak discharge occurs between the scan electrode 2 and the sustain electrode 3 and between the scan electrode 2 and the data electrode 4. In the second priming period T14, the potential of the data electrode 4 is fixed to the ground potential (GND), and the final potential of the scanning electrode 2 is almost equal to the potential of the scanning pulse a in the scanning period T2. . Further, in the final state of the weak discharge, the wall charges of the two electrodes change due to the discharge, and a limit state is reached where the discharge does not occur at this voltage. Therefore, in the second priming period T14, no discharge is generated between the scanning electrode 2 and the data electrode 4 unless the display data pulse e is applied when the scanning pulse a is applied in the scanning period T2. It is in the state of wall charge.

  On the other hand, as a wall charge state, a discharge is generated when a positive pulse is applied to the data electrode 4 even a little, and an address discharge is generated at a low display data pulse e voltage. Yes. However, in actuality, since it takes time for the discharge to occur after the voltage is applied, in order for the discharge to occur between thin pulses such as the scanning pulse a, the display data pulse e Need to have some voltage. As described above, in the initialization period T1, the state in the unit cell 5 is optimal for initialization of wall charges and address discharge. The sustain erasing period T11, the first priming period T13, and the second priming period T14 are all set to a time of about 50 to 150 μsec.

  In the scanning period T2, the wall charge state changes sequentially depending on whether or not the writing discharge is generated for each scanning electrode 2 corresponding to the video signal in, and video information is written in the unit cell 5. That is, the scan pulse a is sequentially applied to the scan electrode 2 (Scani, i = 1, 2,..., N) to which the scan base voltage Vbw is applied. A display data pulse e is applied to the data electrode 4 (Dj, j = 1, 2,..., M) according to the display pattern in accordance with the scanning pulse a. The diagonal lines of the display data pulse e in FIG. 5 indicate that the display data pulse e is applied or not depending on the video signal. Generation of the address discharge is performed as follows. When the display data pulse e is applied, the potential difference between the scan electrode 2 and the data electrode 4 is Vd. At this time, in the initialization period T1, negative wall charges and positive wall charges are formed on the scan electrode 2 and the data electrode 4, respectively. In the discharge space 29 between the scan electrode 2 and the data electrode 4, A wall voltage, which is a voltage applied to the dielectric layer due to these wall charges, is superimposed on the potential difference between the electrodes, and a high voltage is applied. For this reason, a write discharge is generated between the scan electrode 2 and the data electrode 4.

  At this time, since a large potential difference is also applied between scan electrode 2 and sustain electrode 3, when an address discharge occurs between scan electrode 2 and data electrode 4, scan electrode 2 and sustain electrode 3 As shown in FIG. 6E, the scanning electrode 2 accumulates positive wall charges and the sustain electrode 3 accumulates negative wall charges. On the other hand, in the pixel (unit cell 5) to which the display data pulse e is not applied, the potential difference applied to the discharge space 29 between the scan electrode 2 and the data electrode 4 does not exceed the discharge start voltage, so that no discharge occurs. The wall charge situation does not change. As described above, two types of wall charges are obtained depending on the presence or absence of the display data pulse e. When the scan pulse a is applied to all the lines of the scan electrode 2, the sustain period T3 is started.

  In sustain period T3, sustain pulse f of voltage Vs is applied to all scan electrodes 2 and all sustain electrodes 3 alternately. The voltage value Vs of the sustain pulse f is adjusted so that the wall voltage in the vicinity of the discharge gap 23 between the scan electrode 2 and the sustain electrode 3 is substantially equal in the pixels where the address discharge has not occurred. Only Vs which is the potential difference between the two electrodes is applied to the discharge space 29 between the sustain electrode 3 and the surface discharge does not start between the scan electrode 2 and the sustain electrode 3. On the other hand, in the pixel where the write discharge has occurred, positive wall charges are present on the scan electrode 2 side and negative wall charges are present on the sustain electrode 3 side. Therefore, the first positive sustain pulse applied to the scan electrode 2 is present. The positive and negative wall charges are superimposed on f (referred to as the first sustain pulse), a voltage equal to or higher than the discharge start voltage is applied to the discharge space 29, and a sustain discharge is generated.

  Due to this discharge, negative wall charges are accumulated on the scan electrode 2 side, and positive wall charges are accumulated on the sustain electrode 3 side. The next sustain pulse f (referred to as the second sustain pulse) is applied to the sustain electrode 3 side, and the above wall charges are superimposed, so that a sustain discharge is generated here and has a polarity opposite to that of the first sustain pulse. Wall charges are accumulated on the scan electrode 2 side and the sustain electrode 3 side. From this point onward, discharge is continuously generated according to the same principle. That is, the potential difference due to the wall charges generated by the xth sustain discharge is superimposed on the (x + 1) th sustain pulse f, and the sustain discharge continues. The light emission luminance is determined by the number of sustain discharges.

In addition to the above-described plasma display device, conventionally, as this type of technology, for example, there are those described in the following documents.
In the plasma display device described in Patent Document 1, among the subframes obtained by dividing one frame into n (n ≧ 2), in the reset period of at most (n−1) subframes, An appropriate voltage is applied to the address electrode for each emission color according to the cell state of the frame and the emission color of the cell, and it is formed corresponding to the cell state of the immediately preceding subframe regardless of the emission color. Due to the contribution of wall charges, the potential difference between the scan electrode and the address electrode is made higher than the discharge start voltage only in the lit cell of the immediately preceding subframe, and the potential difference between the scan electrode and the address electrode of the extinguished cell is It is prevented that the voltage becomes higher than the discharge start voltage.
For this reason, the background light emission which light-emits the area | region which should be non-light-emitting in a display screen is reduced, and the quality of a display screen improves.
JP 2003-271092 A (Abstract, FIG. 2)

However, the conventional plasma display device has the following problems.
That is, the priming discharge using the weak discharge starts when a voltage equal to or higher than the discharge start voltage is applied to the discharge space 29 in the unit cell 5 and stops when the ramp waveform ends. On the other hand, the priming discharge is generated even in the black display state, but the luminance (black luminance) in the black display state depends on the length of the period in which the priming discharge is generated. For this reason, when the discharge start voltage changes, the black luminance also changes. For example, the unit cell 5 that is lit and the unit cell 5 that is not lit may slightly change the state in each unit cell 5 and may have different discharge start voltages. When the unit cell 5 that is lit in such a state is turned off and black display is performed in the unlit state, the unit cell 5 that has been lit and the unit cell 5 that has not been lit have different black luminances. Therefore, a problem is that the black luminance of the display pattern portion that is lit in the black display state is different and is recognized as an afterimage. Note that the afterimage is a phenomenon in which the discharge start voltage temporarily changes and the display pattern remains, and when the time passes, the original discharge start voltage is restored and the display pattern disappears. Another problem is that burn-in may occur in which the display pattern remains as it is without returning to the original state while the discharge start voltage is changed.

  Examples of problems to be solved by the present invention include these problems. The plasma display device described in Patent Document 1 reduces background light emission in a region that should not emit light in the display screen. This is different from the present invention, and the above problems are improved. Not.

In order to solve the above-described problem, the invention according to claim 1 relates to a plasma display device, and a plasma display panel and a plurality of sub-frames in which one field of the display screen is weighted based on a gradation level. Drive means for driving in a divided manner, the plasma display panel comprising a plurality of surface discharge electrode pairs comprising scan electrodes and sustain electrodes arranged in parallel with each other across a discharge gap, and each surface discharge electrode A plurality of data electrodes intersecting with a pair; and a plurality of unit cells formed in a crossing region between the surface discharge electrode pair and the data electrode; and as the priming discharge to the unit cell, in a manner that gradually increases the potential of the scan electrodes, between the sustain electrode and the scan electrode, Generate a priming discharge in a manner that gradually decreases the potential of the scan electrode after the first priming discharge, between the sustain electrode and the scan electrode, which both generates the second priming discharge, prior to the priming discharge, and applying a positive preliminary discharge data pulse to the data electrodes, and, while setting the scanning electrode or set to a potential higher than the preliminary discharge data pulses, or float, the sustain electrode The priming predischarge for weakening the priming discharge is generated between the data electrode and the sustain electrode by applying a potential lower than that of the predischarge data pulse . .

The invention according to claim 7 relates to a driving method, wherein the plasma display panel and the plasma display panel are driven by dividing one field of the display screen into a plurality of subfields weighted based on the gradation level. The plasma display panel includes a plurality of surface discharge electrode pairs including scan electrodes and sustain electrodes arranged in parallel with each other across a discharge gap, and a plurality of data intersecting with each surface discharge electrode pair. An electrode, and a plurality of unit cells formed in an intersecting region of the surface discharge electrode pair and the data electrode, and the driving means performs priming discharge for each unit cell for each subfield, in a manner that gradually increases the potential of the scan electrodes, between the sustain electrode and the scan electrode, generates a first priming discharge Was, in a manner that gradually decreases the potential of the scan electrode after the first priming discharge, between the sustain electrode and the scan electrode, a plasma display device that is configured to generate a second priming discharge used, the drive means, prior to the priming discharge, whether the positive preliminary discharge data pulse is applied to the data electrodes, and sets the scanning electrode to a potential higher than the preliminary discharge data pulses, or While the float is set, a priming predischarge for weakening the priming discharge is generated between the data electrode and the sustain electrode by applying a potential lower than the predischarge data pulse to the sustain electrode. It is characterized by.

  By generating a single priming preliminary discharge prior to the priming discharge, even if there is a change in the discharge start voltage, a change in black luminance is suppressed, and a plasma display device in which an afterimage is not noticeable is provided.

FIG. 7 is a block diagram showing the electrical configuration of the main part of the plasma display device according to the first embodiment of the present invention.
The plasma display device of this example includes a display panel (PDP) 1, a data driver 31, a scan driver 32, a sustain driver 33, a charge recovery circuit 34, a power supply circuit 35, a signal, as shown in FIG. The processing circuit 41 and the control circuit 42 are included. The PDP 1 has a front substrate and a rear substrate (not shown) arranged to face each other. On the surface of the front substrate facing the back substrate, the scan electrodes 2 and the sustain electrodes 3 are arranged in parallel to each other with a discharge gap (not shown). A scan pulse for performing address discharge is sequentially applied to the scan electrode 2. The scan electrode 2 and the sustain electrode 3 constitute a surface discharge electrode pair, and a sustain pulse is applied to generate a sustain discharge. A plurality of data electrodes 4 are provided on the surface of the rear substrate facing the front substrate so as to intersect with each of the surface discharge electrode pairs, and a display data pulse and an erase data pulse are applied to the data electrode 4. . A unit cell 5 is formed in each intersection region of the surface discharge electrode pair and the data electrode 4. The unit cell 5 is provided for each color of R (red), G (green), and B (blue). The PDP 1 in FIG. 7 has the same configuration as that of the conventional FIG. Further, the unit cell 5 in FIG. 7 has the same configuration as that of the conventional FIG.

  The data driver 31 applies a display data pulse and an erase data pulse corresponding to the display data z to the data electrode 4. The scan driver 32 applies a scan pulse and an erase pulse to the scan electrode 2. The sustain driver 33 applies a sustain pulse to the sustain electrode 3. Under the control of the control circuit 42, the charge recovery circuit 34 recovers the charge of the capacitive component of the PDP 1 and sets the potentials of the scan electrode 2 and the sustain electrode 3 of the PDP 1. The power supply circuit 35 supplies a predetermined high-voltage power supply to the data driver 31, the scan driver 32, the sustain driver 33, and the charge recovery circuit 34. The signal processing circuit 41 includes an A / D conversion circuit, a pixel conversion circuit, a subfield conversion circuit, and the like (not shown). The analog video signal in is converted into a digital video signal by the A / D conversion circuit. The pixel number of the signal is converted into the number of pixels corresponding to PDP1 by the pixel conversion circuit to generate a video signal, and the video signal from the pixel conversion circuit is converted to display data z for each subfield by the subfield conversion circuit. To the data driver 31.

  The control circuit 42 controls the operation timing of the data driver 31, the scan driver 32, the sustain driver 33, and the charge recovery circuit 34, and controls the input of the voltage generated by the power supply circuit 35. Timing signals (horizontal synchronization signal, vertical synchronization signal) H and V are input to the signal processing circuit 41 and the control circuit 42 to synchronize these operations with the display screen. The control circuit 42 sets a scanning period, a sustain period, and an initialization period (preliminary discharge period) for each subfield. That is, in the scanning period, a scanning pulse is applied to each scanning electrode 2 in a line sequential manner, and at the same time, a display data pulse synchronized with the scanning pulse is applied to each data electrode 4 to generate an address discharge in the selected unit cell 5. . In the sustain period, a sustain pulse is alternately applied to each sustain electrode 3 and each scan electrode 2 to cause each unit cell 5 to emit light. In the initialization period, the sustain erasing discharge for the unit cells 5 that emit light in the sustain period and the priming discharge for all the unit cells 5 are performed. In particular, in this embodiment, the control circuit 42 generates a priming preliminary discharge for weakening the priming discharge prior to the priming discharge in the initialization period.

  In addition, the control circuit 42 generates the priming discharge between the scan electrode 2 and the sustain electrode 3 across the discharge gap 23 and generates the priming preliminary discharge between the data electrode 4 and the sustain electrode 3. . In this priming discharge, a first priming discharge that gradually increases the potential of the scan electrode 2 and a second priming discharge that gradually decreases the potential of the scan electrode 2 after the first priming discharge are generated. In this priming preliminary discharge, a positive preliminary discharge data pulse is applied to the data electrode 4. At this time, the potential of the scan electrode 2 is set higher than the potential of the data electrode 4 or is set to float. Further, the pulse width of the preliminary discharge data pulse is set for each color of R, G, B, or the pulse voltage of the preliminary discharge data pulse is set for each color of R, G, B.

  Further, when one field of the display screen is constituted by lighting display of only one subfield of the plurality of subfields, the signal processing circuit 41 does not light up in the subfield in which the priming preliminary discharge is generated. Subfield coding.

FIG. 8 is a diagram showing driving waveforms of each part for explaining the operation of the plasma display device of FIG. 7, FIG. 9 is a schematic diagram showing the state of wall charges in the unit cell 5 at each timing, and FIG. 10 is initialization. The figure which shows the light emission waveform in a period, FIG. 11 is a figure which shows the concept of the luminance change in priming discharge, and FIG. 12 is a figure which shows the black luminance change before and behind fixed display.
With reference to these drawings, processing contents of the driving method used in the plasma display device of this example will be described.
In this plasma display device, for example, gradation display is performed by the scan sustaining separation driving method shown in FIG. 4, and in particular, in this embodiment, prior to the priming discharge in the initialization period, a priming preliminary for weakening the priming discharge is performed. Discharge occurs.

  That is, as shown in FIG. 8, the voltage shown in the waveform Sus is applied to the sustain electrode 3, and the voltages shown in the waveforms Scan1,..., Scann are sequentially applied to the scan electrode 2. Further, a voltage indicated by the waveform Data is applied to the data electrode 4. In the sustain erasure period T11 of the initialization period T1, the sustain erasure discharge is generated only when the unit cell 5 is lit in the previous subfield. When the sustain discharge is generated in the previous subfield, the wall charge arrangement shown in FIG. 9A is obtained by the final sustain pulse. Thereafter, the potential of the scan electrode 2 gradually decreases in the sustain / erase period T <b> 11, and weak discharge starts when the discharge start voltage is exceeded in the discharge gap 13. At the end of the sustain erasing period T11, the wall charge arrangement shown in FIG. 9B is obtained.

  Next, the priming period T12 is entered. The priming period T12 includes a first priming period T13 and a second priming period T14. In the first priming period T13, the potential of the scan electrode 2 gradually increases and the first priming discharge is generated in the discharge gap 13. In the second priming period T <b> 14, the potential of the scan electrode 2 gradually decreases after the first priming discharge, and a second priming discharge is generated in the discharge gap 23. In this embodiment, a preliminary discharge data pulse p for generating a priming preliminary discharge is applied to the data electrode 4 at the beginning of the first priming period T13. The voltage of the preliminary discharge data pulse p is the same as the voltage of the display data pulse e. At the timing when the preliminary discharge data pulse p is applied, the potential of the sustain electrode 3 is the ground potential.

  For this reason, as shown in FIG. 9B, the negative wall charge from the discharge gap 23 of the sustain electrode 3 and the positive wall charge formed on the data electrode 4 cause a gap between the sustain electrode 3 and the data electrode 4. Opposing single priming pre-discharge occurs. This priming preliminary discharge is a weak discharge of 1/3 or less compared to the discharge intensity of the sustain discharge generated in the sustain period T3. Here, the reason why the discharge is weak is that the wall voltage of the voltage formed on the transparent dielectric layer 24 by the negative wall charge on the sustain electrode 3 is small and the range in which the negative wall charge is formed is small. Due to the occurrence of this priming preliminary discharge, the wall charges are arranged as shown in FIG. Thereafter, when the potential of the scan electrode 2 rises, a voltage equal to or higher than the discharge start voltage is applied to the discharge gap 23, and the first priming discharge is generated. The first priming discharge is a weak discharge, and the discharge continues continuously while the potential of the scan electrode 2 is changing.

  At this time, as shown in FIG. 10A, the light emission intensity by the first priming discharge is weaker than the conventional light emission intensity shown in FIG. This is due to the priming effect in which a large amount of priming particles are present in the unit cell 5 due to the occurrence of the priming preliminary discharge before the first priming discharge, and the discharge is smoothly generated. At the end of the first priming discharge period T13, the wall charge arrangement shown in FIG. Next, the second priming period T14 is entered. In the second priming period T14, in contrast to the first priming period T13, the potential of the scan electrode 2 changes in a decreasing direction. For this reason, the wall charge changes in a direction to decrease the wall charge formed in the first priming period T13. Here, as shown in FIG. 10A, the light emission intensity by the second priming discharge is weaker than the conventional light emission intensity shown in FIG. This is also due to the priming effect by the priming preliminary discharge.

  As described above, by using the driving method of this embodiment, the emission intensity of the priming discharge is weakened. In the case of black display, discharge occurs only in the priming period T12. For this reason, the luminance of black display is conventionally determined by the luminance of the priming discharge. In the case of a weak discharge, as shown in FIG. 11B, the luminance of the discharge depends on the light emission intensity and the discharge time. In the priming discharge, the discharge starts from a point in time when a voltage equal to or higher than the discharge start voltage is applied to the discharge gap 23. Therefore, when the discharge start voltage changes, the luminance of black display changes. An afterimage or burn-in in which the previous display pattern remains even when black is displayed is caused by the change in the discharge start voltage. Here, afterimage is a phenomenon in which the discharge start voltage temporarily changes and the display pattern remains, and after a while, it returns to the original discharge start voltage and the display pattern disappears. Burn-in is the start of discharge. This is a phenomenon in which the display pattern remains as it is without returning to its original state with the voltage changed. It is assumed that the discharge start timing is changed by the time Δtf when the discharge start voltage is changed by the voltage ΔVf. If the emission intensity of the priming discharge is L, the luminance changes by L · Δtf. Therefore, if the change in time Δtf, that is, the change in voltage ΔVf is the same, the smaller the emission intensity L, the smaller the change in luminance. As shown in FIG. 10A, in this embodiment, since the light emission intensity L is smaller than that in the prior art, the luminance change in the priming discharge portion is small.

  On the other hand, in this embodiment, priming preliminary discharge occurs during black display. This priming preliminary discharge is discharged even when the discharge start voltage changes, because the timing at which the discharge occurs does not change with the timing at which the preliminary discharge data pulse p is applied, and the discharge is also single. There is no change in time. However, the discharge intensity changes slightly. As the discharge start voltage decreases, the discharge intensity changes in the increasing direction. In this embodiment, since the priming preliminary discharge is sufficiently small with respect to the change of the priming discharge, the luminance change of the priming discharge is almost the luminance change of black display. Therefore, the luminance change is smaller in this embodiment having a smaller light emission intensity L than in the prior art.

  For example, as shown in FIG. 12, the change in black luminance after the fixed display for 10 minutes is lower in the present embodiment because the luminance of the black display before the fixed display is smaller. It has become. In addition, the luminance change amount and the luminance change rate after fixed display are smaller in this embodiment. Here, the luminance change amount is a difference in luminance before and after the fixed display, and the luminance change rate is a luminance ratio before and after the fixed display. When the luminance change amount and the luminance change rate are both smaller, afterimages and image sticking are not noticeable. Therefore, in this embodiment, a plasma display device in which afterimages and image sticking are not noticeable is provided. After this initialization period T1, the driving in the scanning period T2 and the sustain period T3 is performed as in the conventional FIG.

  As described above, in the first embodiment, prior to the priming discharge in the priming period T12, the priming predischarge by the single predischarge data pulse p is generated, so that the subsequent priming discharge of the continuous weak discharge is performed. Is weakened. For this reason, even if the discharge start voltage is changed and the start timing of the priming discharge is changed, the emission intensity of the priming discharge is weak, so that the amount of change in luminance can be suppressed to be smaller than that of the conventional case. As a result, when a black display is performed, an afterimage, which is a phenomenon in which a display pattern previously displayed, remains is inconspicuous.

FIG. 13 is a diagram showing driving waveforms of respective parts for explaining the driving method according to the second embodiment of the present invention, and FIG. 14 is a schematic diagram showing the state of wall charges in the unit cell 5 at each timing. .
The processing contents of the driving method used in the plasma display device of FIG. 7 will be described with reference to these drawings.
In the driving method of this example, the potential of the scan electrode 2 when the preliminary discharge data pulse p is applied in the initialization period T1 is in a floating state (that is, the scan electrode 22 is in a high impedance state). Since the sustain erasing period T11 is the same as that of the first embodiment, the wall charge arrangement at the end of the sustain erasing period T11 is the same as that shown in FIG. 9B, as shown in FIG. 14B. Next, when the preliminary discharge data pulse p is applied, the potential of the sustain electrode 3 is the ground potential as in the first embodiment, and the opposing priming preliminary discharge is performed between the sustain electrode 3 and the data electrode 4. appear. At this time, since the potential of the scan electrode 2 is Vs in the first embodiment, when the preliminary discharge data pulse p is applied, the potential difference between the scan electrode 2 and the data electrode 4 becomes (Vs−Vd).

  In the sustain period T3, the potential difference between the scan electrode 2 and the data electrode 4 is Vs. When discharge occurs and space charge is generated, the wall charge arrangement changes, and the potential difference between the electrodes is different between the electrodes. A near wall voltage is formed. For this reason, in Example 1, the wall voltage of Vs decreases to near (Vs−Vd) as shown by the broken line in FIG. However, at the time of the next first priming discharge, the potential difference between the scan electrode 2 and the data electrode 4 increases simultaneously with the surface discharge, so that the space charge goes back and forth, and the wall charge increases, as shown in FIG. As shown by the broken line, the wall charge amount necessary for writing can be secured. However, the wall charge that increases in the first priming discharge is mainly at the portion from the discharge gap 13, and the wall charge from the non-discharge gap that is actually used for writing is shown by the broken line in FIG. As shown, it is not as formed as in the prior art. For this reason, the voltage Vdmin of the minimum display data pulse e necessary for writing increases.

  In this embodiment, in order to suppress an increase in the voltage Vdmin, the potential of the scan electrode 2 when the preliminary discharge data pulse p is applied is in a floating state. Since it is in a floating state, when the preliminary discharge data pulse p is applied, the potential of the scan electrode 2 is raised by capacitive coupling as shown in FIG. For this reason, the decreasing range of the potential difference between the scanning electrode 2 and the data electrode 4 is reduced, and as shown in FIG. 14C, the decrease of the wall charge after the priming preliminary discharge is suppressed.

  Thereafter, in the first priming discharge period T13, similarly to the first embodiment, the surface is weakly discharged, and the charge is transferred between the scanning electrode 2 and the data electrode 4 in the vicinity of the discharge gap 13, and FIG. ), The wall charge arrangement changes. Thereafter, the second priming discharge period T14 is entered, the wall charges change in a direction to decrease the wall charge formed by the first priming discharge T13, and at the end of the second priming discharge period T14, FIG. The wall charge arrangement shown in (e) is obtained.

Comparing FIG. 14 with FIG. 9 of the first embodiment, the difference in wall voltage formed from the non-discharge gap of the scan electrode 2 during the priming preliminary discharge remains as it is until the end of the second priming discharge period T14. Compared to Example 1, the negative wall voltage is higher in this example.
As a result, Vdmin = 46V in the conventional driving, whereas Vdmin = 51V in the first embodiment and Vdmin = 48V in the present embodiment. On the other hand, afterimage and image sticking can be reduced because the discharge intensity of the subsequent priming discharge can be weakened by the priming preliminary discharge. As specific numerical values, the same results as those of Example 1 shown in FIG. 12 are obtained. After this initialization period T1, the driving in the scanning period T2 and the sustain period T3 is performed as in the conventional FIG.

FIG. 15 is a diagram showing driving waveforms of respective parts for explaining a driving method according to a third embodiment of the present invention, and FIG. 16 is a schematic diagram showing a state of wall charges in the unit cell 5 at each timing. .
In the driving method of this example, the potential of the scan electrode 2 when the preliminary discharge data pulse p is applied in the initialization period T1 becomes (Vs + Vd), and the priming is performed in order to suppress the reduction of the wall charge as in the second embodiment. The potential difference between the scan electrode 2 and the data electrode 4 when the preliminary discharge is generated is kept at Vs. By doing so, even if the priming preliminary discharge occurs, the wall voltage Vs formed between the scan electrode 2 and the data electrode 4 at the end of the sustain / erase period T11 does not decrease. As a result, the same Vdmin as in the prior art can be obtained, and a sufficient drive margin for the voltage of the display data pulse e can be ensured as in the prior art.

  Until the end of the sustaining / erasing period T11, the wall charge arrangement is the same as in the first and second embodiments as shown in FIGS. 16 (a) and 16 (b). Next, when the preliminary discharge data pulse p is applied, a priming preliminary discharge is generated between the sustain electrode 3 and the data electrode 4. At this time, since the potential difference Vs is generated between the scanning electrode 2 and the data electrode 4, the wall voltage Vs formed in the stage of FIG. 16A is as shown in FIG. Only the wall charges in the vicinity of the discharge gap 23 change. Thereafter, in the first priming period T13 and the second priming period T14, as in the first and second examples, weak discharge only occurs in the vicinity of the discharge gap 23, so FIG. , (E) shows the wall charge arrangement.

  As described above, in this embodiment, the wall voltage from the non-discharge gap of the scan electrode 2 hardly changes from the end of the sustain / erase period T11, and is the same wall voltage as in the conventional driving shown in FIG. Can do. As a result, Vdmin at the time of writing is 46 V, which is the same voltage as in the prior art. On the other hand, with respect to afterimage and image sticking, the discharge intensity of the following priming discharge can be weakened by the priming preliminary discharge. The same result as that of Example 1 shown in FIG. 12 is obtained. After the initialization period T1, driving in the scanning period T2 and the sustain period T3 is performed.

  The priming preliminary discharge generated by the preliminary discharge data pulse p is a counter discharge between the sustain electrode 3 and the data electrode 4. For this reason, when a preliminary discharge data pulse p having the same pulse width is applied to the R, G, B unit cells 5, depending on the type of phosphor on the data electrode, depending on the type of phosphor on the data electrode, changes in the discharge start voltage due to afterimages or image sticking The amount may vary. If the amount of change is different, the balance of the discharge intensity of the priming preliminary discharge in R, G, and B will be different depending on the afterimage and printing. As a result, the color of the fixed display part is different from the other peripheral parts when black display is selected. In some cases, afterimages and image sticking may be noticeable due to differences in color other than luminance differences. A driving method that improves this point will be described in the fourth embodiment.

FIG. 17 is a diagram showing driving waveforms of respective parts for explaining the driving method according to the fourth embodiment of the present invention, and FIG. 18 shows fixed display of the first and fourth to sixth embodiments and the conventional plasma display device. It is xy chromaticity diagram which shows the change of the chromaticity coordinate of the black display before and behind.
The processing contents of the driving method used in the plasma display device of FIG. 7 will be described with reference to these drawings.
In the driving method of this example, the pulse width of the preliminary discharge data pulse p in the initialization period T1 is set for each color of R, G, B of the phosphor of the unit cell 5. For example, as shown in FIG. 17, 2.0 μsec is set for the R unit cell 5, 2.4 μsec is set for the G unit cell 5, and 3.0 μsec is set for the B unit cell 5. Accordingly, as shown in FIG. 18, it can be seen that the change in the chromaticity diagram is smaller in this embodiment than in the case where the preliminary discharge data pulse p having the same pulse width is applied (embodiment 1). On the other hand, with respect to afterimage and image sticking as seen from the luminance, the discharge intensity of the subsequent priming discharge can be weakened by the priming preliminary discharge. As numerical values, almost the same results as those of Example 1 shown in FIG. 12 are obtained. After the initialization period T1, driving in the scanning period T2 and the sustain period T3 is performed.

FIG. 19 is a diagram showing drive waveforms of respective parts for explaining a drive method according to the fifth embodiment of the present invention.
The processing contents of the driving method used in the plasma display device of FIG. 7 will be described with reference to these drawings.
In the driving method of this example, the pulse voltage of the preliminary discharge data pulse p in the initialization period T1 is set for each color of R, G, B of the phosphor of the unit cell 5, and as in the fourth embodiment, R , G, and B have different afterimages and variations in the discharge start voltage due to image sticking. For example, as shown in FIG. 19, 68 V is set for the R unit cell 5, 70 V is set for the G unit cell 5, and 73 V is set for the B unit cell 5. Thus, as shown in FIG. 18, it can be seen that the change in the chromaticity diagram is smaller in this embodiment than in the case where the preliminary discharge data pulse p having the same pulse voltage is applied (embodiment 1). On the other hand, with respect to afterimage and image sticking as seen from the luminance, the discharge intensity of the subsequent priming discharge can be weakened by the priming preliminary discharge, so that it is reduced in the same manner as in the first and second embodiments. As a numerical value, almost the same result as that of Example 1 shown in FIG. 12 is obtained. After the initialization period T1, driving in the scanning period T2 and the sustain period T3 is performed.

  In the driving method according to the sixth embodiment of the present invention, the pulse width of the preliminary discharge data pulse p is set narrower than the pulse width in the fourth embodiment. For example, 1.0 μsec is set for the R unit cell 5, 1.2 μsec is set for the G unit cell 5, and 1.5 μsec is set for the B unit cell 5. The unit cell 5 lit in the previous subfield has a low discharge start voltage. For this reason, when the pulse width of the preliminary discharge data pulse p is narrowed as in this embodiment, no priming preliminary discharge occurs in the unit cell 5 that is not lit in the previous subfield, and the unit cell 5 that is lit in the previous subfield. Only priming pre-discharge occurs. Thereby, an afterimage and image sticking can be almost eliminated. For example, as shown in FIG. 12, the change in black luminance after 10 minutes of fixed display has a smaller amount of change in luminance and a rate of change in luminance than in the first embodiment.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and even if there is a design change without departing from the gist of the present invention, Included in the invention.
For example, in the above-described embodiment, the scan sustain separation drive method in which the scan period T2 and the sustain period T3 are completely separated has been described, but the scan sustain simultaneous drive method in which the scan pulse is applied at the same timing as the sustain pulse, Even in the scan sustain mixed drive system in which the scan pulse is applied so that there is no temporal overlap between a certain sustain pulse and another sustain pulse, substantially the same operation and effect as in the above embodiment can be obtained. Further, the PDP 1 may be configured such that three electrodes of the scan electrode 2, the sustain electrode 3, and the data electrode 4 are provided on one of the front substrate and the rear substrate.

It is a block diagram which shows the electrical constitution of the conventional plasma display apparatus. It is a block diagram which shows the principal part of PDP1 in FIG. It is the DD sectional view taken on the line of the unit cell 5 in FIG. It is a figure explaining the principle of the gradation display method by the scanning maintenance separation drive system used for PDP of FIG. It is a figure which shows the principal part of the drive waveform used for a scanning maintenance separation drive system. It is a schematic diagram which shows the state of the wall charge in the unit cell 5 in each timing. It is a block diagram which shows the electrical constitution of the principal part of the plasma display apparatus which is 1st Example of this invention. It is a figure which shows the drive waveform of each part explaining the operation | movement of the plasma display apparatus of FIG. It is a schematic diagram which shows the state of the wall charge in the unit cell 5 in each timing. It is a figure which shows the light emission waveform in an initialization period. It is a figure which shows the concept of the brightness | luminance change in priming discharge. It is a figure which shows the change of the black luminance before and behind fixed display. It is a figure which shows the drive waveform of each part explaining the drive method which is 2nd Example of this invention. It is a schematic diagram which shows the state of the wall charge in the unit cell 5 in each timing. It is a figure which shows the drive waveform of each part explaining the drive method which is the 3rd Example of this invention. It is a schematic diagram which shows the state of the wall charge in the unit cell 5 in each timing. It is a figure which shows the drive waveform of each part explaining the drive method which is the 4th Example of this invention. FIG. 6 is an xy chromaticity diagram showing a change in chromaticity coordinates of black display before and after fixed display of Example 1 and Examples 4 to 6 and a conventional plasma display device. It is a figure which shows the drive waveform of each part explaining the drive method which is 5th Example of this invention.

Explanation of symbols

1 Display panel (PDP, plasma display panel)
2 Scanning electrode (part of PDP)
3 Sustain electrodes (part of PDP)
4 Data electrode (part of PDP)
5 Unit cell (part of PDP)
6 Surface discharge electrode pair (part of PDP)
21 Front substrate (first substrate, part of PDP)
22 Back substrate (second substrate, part of PDP)
23 Discharge gap (part of PDP)
24 Transparent dielectric layer (part of PDP)
25 Protective layer (part of PDP)
26 White dielectric layer (part of PDP)
27 Phosphor layer (part of PDP)
28 Bulkhead (part of PDP)
29 Discharge space (part of PDP)
31 Data driver (part of driving means)
32 Scanning driver (part of driving means)
33 Maintenance driver (part of driving means)
34 Charge recovery circuit (part of driving means)
35 Power supply circuit (part of drive means)
41 Signal processing circuit (part of driving means)
42 Control circuit (part of drive means)
T1 initialization period T2 scan period T3 sustain period T11 sustain erase period T12 priming period T13 first priming period T14 second priming period p preliminary discharge data pulse a scan pulse e display data pulse f sustain pulse

Claims (7)

A plasma display panel, and driving means for driving the plasma display panel by dividing one field of a display screen into a plurality of subfields weighted based on a gradation level,
The plasma display panel includes a plurality of surface discharge electrode pairs composed of scan electrodes and sustain electrodes arranged in parallel with each other across a discharge gap, a plurality of data electrodes intersecting the surface discharge electrode pairs, and the surface discharge. A plurality of unit cells formed in the intersection region of the electrode pair and the data electrode,
Said drive means, said each sub-field, as the priming discharge for each of the unit cell, in a manner to gradually increase a potential of the scan electrodes, between the sustain electrode and the scan electrode, a first priming discharge And generating a second priming discharge between the scan electrode and the sustain electrode in a manner that gradually decreases the potential of the scan electrode after the first priming discharge,
Prior to the priming discharge, and applying a positive preliminary discharge data pulse to the data electrodes, and, while setting the scanning electrode or set to a potential higher than the preliminary discharge data pulses, or float, the sustain electrode The priming predischarge for weakening the priming discharge is generated between the data electrode and the sustain electrode by applying a potential lower than the predischarge data pulse to the data electrode. Plasma display device. The driving means includes
2. The plasma display device according to claim 1 , wherein a potential of the scan electrode when the preliminary discharge data pulse is applied to the data electrode is set higher than a potential of the data electrode. The driving means includes
2. The plasma display device according to claim 1 , wherein the potential of the scan electrode when the preliminary discharge data pulse is applied to the data electrode is set to float. Each unit cell is
Provided for each color of R (red), G (green), B (blue),
The driving means includes
The priming preliminary discharge is performed only when each unit cell emits light in the previous subfield with respect to the preliminary discharge data pulse in the subfield for each color of R, G, and B for the pulse width of the preliminary discharge data pulse. 4. The plasma display device according to claim 1, wherein the generated pulse width is set to be set. Each unit cell is
Provided for each color of R (red), G (green), B (blue),
The driving means includes
For each color of R, G, and B, with respect to the preliminary discharge data pulse in the subfield, the pulse voltage is set so that the priming preliminary discharge is generated only when each unit cell emits light in the previous subfield. The plasma display device according to any one of claims 1 to 4, wherein the plasma display device is provided. The driving means is one of the display screens.
2. The plasma display device according to claim 1, wherein the priming preliminary discharge is not generated when a field is configured to display only one subfield of the plurality of subfields. A plasma display panel, and driving means for driving the plasma display panel by dividing one field of a display screen into a plurality of subfields weighted based on a gradation level,
The plasma display panel includes a plurality of surface discharge electrode pairs composed of scan electrodes and sustain electrodes arranged in parallel with each other across a discharge gap, a plurality of data electrodes intersecting the surface discharge electrode pairs, and the surface discharge. A plurality of unit cells formed in the intersection region of the electrode pair and the data electrode,
Said drive means, said each sub-field, as the priming discharge for each of the unit cell, in a manner to gradually increase a potential of the scan electrodes, between the sustain electrode and the scan electrode, a first priming discharge And a second priming discharge is generated between the scan electrode and the sustain electrode in such a manner that the potential of the scan electrode gradually decreases after the first priming discharge. Used in display devices,
Said drive means, said prior to the priming discharge, and applying a positive preliminary discharge data pulse to the data electrode, and setting the scan electrode or set to a potential higher than the preliminary discharge data pulses, or the float Meanwhile, a priming preliminary discharge for weakening the priming discharge is generated between the data electrode and the sustain electrode by applying a potential lower than the preliminary discharge data pulse to the sustain electrode. Driving method.

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