JP4228580B2 - Driving method of AC type plasma display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for driving an AC plasma display panel.
[0002]
[Prior art]
8A and 8B are cross-sectional views of an AC type plasma display panel. As shown in FIG. 8, the panel 1 has a glass surface substrate 3 and a glass back substrate 4 facing each other with a discharge space 2 interposed therebetween, and radiates ultraviolet rays into the gap by discharge. Gas, neon, helium and xenon. On the surface substrate 3, an electrode group composed of a pair of strip-like scan electrodes 7 and sustain electrodes 8 covered with the dielectric layer 5 and the protective film 6 is arranged in parallel with each other. The scan electrode 7 and the sustain electrode 8 are composed of transparent conductive films 7a and 8a made of ITO and bus electrodes 7b and 8b made of Ag, respectively.
[0003]
On the back substrate 4, a plurality of strip-like address electrodes 9 are arranged in parallel to each other in a direction orthogonal to the scan electrodes 7 and the sustain electrodes 8, and each address electrode 9 is isolated and a discharge space 2 is formed. A strip-shaped partition wall 10 is provided between the address electrodes 9. A phosphor layer 11 is formed from the address electrode 9 to the side surface of the barrier rib 10.
[0004]
This panel 1 is configured to view an image display from the surface substrate 3 side, and excites the phosphor layer 11 by ultraviolet rays generated by the discharge between the scan electrode 7 and the sustain electrode 8 in the discharge space 2. The visible light from the phosphor layer 11 is used for display light emission.
[0005]
Next, a method for displaying image data on the conventional panel 1 will be described.
[0006]
As a conventional method of driving a panel, one field period is divided into a plurality of subfields having a light emission period weight based on the binary system, and gradation display is performed by a combination of subfields to emit light. Each subfield includes an initialization period, an address period, and a sustain period.
[0007]
In order to display image data, different signal waveforms are applied to each electrode in the initialization period, the address period, and the sustain period. In the initialization period, for example, a positive pulse voltage is applied to all the scan electrodes 7 with respect to the sustain electrodes 8 and the address electrodes 9, and wall charges are accumulated on the protective film 6 and the phosphor layer 11.
[0008]
In the address period, scanning is performed by sequentially applying negative pulses to all the scanning electrodes 7. If there is display data, while scanning the scan electrodes 7, by applying a positive data pulse to the address electrodes 9, a discharge occurs between the scan electrode 7 and the address electrodes 9, on the scanning electrode 7 of Wall charges are formed on the surface of the protective film 6.
[0009]
In the subsequent sustain period, a voltage sufficient to maintain the discharge is applied between scan electrode 7 and sustain electrode 8 for a certain period. Thereby, discharge plasma is generated between the scan electrode 7 and the sustain electrode 8, and the phosphor layer 11 is excited to emit light for a certain period. In the discharge space where no data pulse is applied in the address period, no discharge occurs and excitation light emission of the phosphor layer 11 does not occur.
[0010]
By the way, in driving the AC type plasma display panel, it is necessary to initialize all the cells of the panel. This is called full initialization. By performing the entire surface initialization, the AC type plasma display has a problem that the background luminance increases and the contrast deteriorates.
[0011]
Therefore, in order to realize high contrast, Japanese Patent Application No. 11-42549 achieves high contrast by limiting the initialization performed on all the pixels of the panel to some subfields in one field period. ing. In Japanese Patent Application No. 11-42549, the initialization performed on all the pixels of the panel is performed with a weak discharge using a continuously changing ramp voltage waveform, so that the background luminance is about 0.15 cd / m ^2. The small value is realized.
[0012]
[Problems to be solved by the invention]
FIG. 9 shows drive waveforms of a conventional AC type plasma display panel that can realize high contrast. 9A shows a voltage waveform applied to the scan electrode 7, FIG. 9B shows a voltage waveform applied to the sustain electrode 8, and FIG. 9C shows a voltage waveform applied to the address electrode 9. FIG. 9D shows a discharge light emission waveform.
[0013]
In an AC plasma display panel, it is necessary to initialize all the pixels of the panel at least once per field. This full initialization is not performed for all subfields, but only for some of the subfields, and the remaining subfields are initialized only for the cells maintained in the previous subfield, resulting in high contrast. Can be realized. That is, in the cell that is not lit in the nth subfield, the initialization discharge is not performed in the (n + 1) th subfield. As a result, a small background luminance can be realized. In addition, the background luminance can be further suppressed by using a weak lamp discharge using a ramp voltage waveform in which the voltage gradually changes for the entire surface initialization.
[0014]
As described above, by using the conventional driving waveform shown in FIG. 9, driving with reduced background luminance is realized. However, when this driving waveform is used, since the write discharge intensity is as large as the sustain discharge intensity, the heat generation of the switching IC of the scan pulse and the voltage drop of the scan electrode voltage at the time of writing are large, and reliability is improved. There was a big challenge.
[0015]
In view of the above problems, the present invention provides a driving method that simultaneously realizes high contrast and high reliability.
[0016]
[Means for Solving the Problems]
In the driving method of the AC type plasma display panel of the present invention, at the end of the sustain period, an upward ramp voltage in which the scan electrode side becomes an anode after applying a pulse voltage that causes the sustain electrode to be an anode and causing a sustain discharge. The waveform is applied to cause discharge, and the initializing operation thereafter is characterized in that the falling ramp voltage waveform is applied immediately after the rising ramp voltage waveform is applied .
[0017]
By this method, it is possible to realize a highly reliable driving method of an AC plasma display panel having high contrast and low heat generation of the scan IC and low scan electrode voltage drop at the time of writing.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
That is, according to the present invention, a surface substrate in which an electrode group composed of scan electrodes and sustain electrodes is arranged in parallel to each other, and a plurality of address electrodes are arranged in parallel to each other in a direction perpendicular to the scan electrodes and sustain electrodes. An AC type plasma display panel by arranging the front substrate and the rear substrate so as to face each other with a discharge space therebetween, and a plurality of fields each having an address period and a sustain period. This is a driving method of an AC type plasma display panel, which is constituted by subfields, and the entire initializing operation performed on all the pixels of the panel is limited to a part of the subfields. Upward ramp voltage waveform with the scan electrode side serving as the anode after applying a pulse voltage that serves as the anode and causing a sustain discharge Applied to cause discharge, the subsequent initialization operations, after the application of ramp voltage waveform of the uplink is a driving method which is characterized in that immediately applying a ramp voltage waveform of the downlink.
[0019]
Hereinafter, a method for driving a plasma display panel according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7, but the embodiment of the present invention is not limited thereto.
[0020]
FIG. 1 shows a driving waveform in a driving method of a plasma display panel according to an embodiment of the present invention. FIG. 1 (a) shows a voltage waveform applied to scan electrode 7, and FIG. 1 (b) shows a sustain electrode. FIG. 1C shows the voltage waveform applied to the address electrode 9, and FIG. 1D shows the discharge light emission waveform. FIG. 2A shows an address discharge waveform when the conventional drive waveform is used, and FIG. 2B shows an address discharge waveform when the drive waveform of the present invention is used. Further, FIG. 3 shows the state of wall charges at the time of erasing and initialization using the conventional driving method, and FIG. 3A shows the state of the wall charges after the erasing discharge is finished. FIG. 3B shows the state of wall charge after wall charge adjustment by lamp discharge, and FIG. 3C shows the state of wall charge after write discharge has occurred. Further, FIG. 4 shows the state of wall charges at the time of erasing and initialization when the driving method of the present invention is used. FIG. 4A shows the wall charges after the end of the sustain discharge or the erasing discharge. FIG. 4B shows the state of wall charge after erasing and wall charge adjustment using weak lamp discharge with a ramp voltage waveform, and FIG. 4C shows the wall after completion of the write discharge. The state of charge is shown respectively.
[0021]
First, erase and initialization operations in the conventional driving method shown in FIG. 9 will be described. In the conventional driving method shown in FIG. 9, as shown in FIG. 3A, the last erasing operation in the sustain period is the same as the sustain discharge by applying a narrow pulse voltage so that the scan electrode side becomes the anode. A strong pulse discharge is generated. In the subsequent initialization operation, wall charge adjustment is performed by weak lamp discharge using a downward ramp voltage waveform that changes continuously or intermittently. The lamp discharge at that time is such that the scan electrode 7 side becomes a cathode.
[0022]
In the conventional driving method, after applying a pulse voltage waveform such that the scan electrode side becomes an anode and causing a discharge, a negative voltage is formed on the dielectric on the scan electrode 7 as shown in FIG. It is considered that positive wall charges are accumulated on the dielectric on the sustain electrode 8. Then, after that, the wall discharge in the vicinity of the discharge gap is adjusted by causing the lamp discharge with the ramp voltage waveform as shown in FIG.
[0023]
At this time, since the weak lamp discharge by the ramp voltage waveform is used when adjusting the wall charge, only the wall charge near the discharge gap is adjusted. Therefore, negative and positive charges remain on the scanning electrode side and the sustain electrode side on the dielectric that is far from the discharge gap, respectively.
[0024]
In this state, as shown in FIG. 3C , when a write discharge is generated such that the scan electrode side becomes a cathode, positive charges are generated on the scan electrode side serving as the cathode, and the sustain electrode side serving as the anode is present. Negative charges are accumulated, and the write discharge ends. At this time, as shown in FIG. 3B, it can be seen that the negative wall charge accumulated on the scan electrode before the write discharge is inverted to the positive wall charge. On the other hand, it can also be seen that the positive wall charges accumulated on the sustain electrodes are inverted to the negative wall charges before the write discharge.
[0025]
In the conventional write discharge, it is necessary to invert the polarity of the wall charges accumulated on the dielectric away from the discharge gap, so that a lot of charges move at the time of writing. That is, a large address discharge current flows , and a strong address discharge occurs as shown in FIG.
[0026]
On the other hand, in the erase and initialization operations in the driving method of the present invention shown in FIG. 1, the last erase operation in the sustain period is applied with a pulse voltage so that the sustain electrode side becomes the anode as shown in FIG. Then , after causing the sustain discharge , a weak ramp discharge is generated by applying an upward ramp voltage waveform in which the scan electrode 7 side becomes the anode. In the subsequent initialization operation, after applying the rising ramp voltage waveform, the falling ramp voltage waveform is immediately applied to cause weak lamp discharge to perform wall charge adjustment.
[0027]
In the driving method of the present invention, as shown in FIG. 4 (a), at the end of the sustain, a discharge is caused by a pulse voltage such that the sustain electrode becomes the anode, and during the subsequent erasing operation , continuously or intermittently. Using a changing voltage waveform, a weak lamp discharge is caused such that the scanning electrode side becomes an anode.
[0028]
In FIG. 4 (a), during the sustain discharge ends with a pulse voltage waveform as the sustain electrode side is an anode, the positive charge on the dielectric of the scan electrodes, whereas a minus on the dielectric of the sustain electrode It can be seen that wall charges are accumulated.
[0029]
Thereafter, an erasing operation in which an upward ramp voltage waveform is applied so that the scan electrode side serves as an anode, and wall charges to which a downward ramp voltage waveform is applied are adjusted . FIG. 4B shows the state of the wall charge after this erasing operation and wall charge adjustment, and this is the wall charge distribution before the write discharge occurs.
[0030]
FIG. 4C shows the state of the wall charges after the end of the write discharge . Since the write discharge is a discharge in which the scan electrode side becomes a cathode and the sustain electrode side becomes an anode, the scan that is the cathode is performed by the write discharge. A positive charge is accumulated on the electrode side and a negative charge is accumulated on the one sustain electrode side, and the writing discharge is completed.
[0031]
At this time, when FIG. 4B and FIG. 4C are compared, it can be seen that only the charges near the discharge gap have moved and the wall charges away from the discharge gap have not changed. Before the write discharge is generated, positive charges are already accumulated on the scan electrodes and negative charges are accumulated on the sustain electrode side, so that the amount of movement of wall charges at the time of write discharge is small. That is, as shown in FIG. 2B, the discharge intensity at the time of writing is small, and the writing discharge current flowing along therewith is also small.
[0032]
In the embodiment of the present invention, the ramp voltage waveform as shown in FIG. 5 is shown as the voltage waveform that changes continuously or intermittently. However, the voltage waveform as shown in FIG. May be.
[0033]
Further, in the embodiment shown in FIG. 1, in the entire initialization period, a ramp voltage waveform that gradually increases the voltage value is applied to the sustain electrode 8 side so that the sustain electrode 8 side becomes an anode. After the lamp discharge is generated, the wall charge is adjusted by causing the lamp discharge such that the sustain electrode side becomes the cathode. By using this waveform, the write discharge intensity in the subfield after the entire surface initialization can be reduced.
[0034]
【The invention's effect】
As described above, according to the present invention, one field is constituted by a plurality of subfields having an address period and a sustain period, and the entire initialization operation performed on all the pixels of the panel is limited to some subfields. In the driving method of the AC type plasma display panel, at the end of the sustain period, an upward ramp voltage in which the scan electrode side becomes an anode after applying a pulse voltage that causes the sustain electrode to be an anode and causing a sustain discharge The waveform is applied to cause a discharge, and the initialization operation thereafter can be performed by applying the descending ramp voltage waveform immediately after applying the ascending ramp voltage waveform, thereby suppressing the background brightness and increasing the contrast. In addition, by using a drive waveform that can make the write discharge intensity smaller than the sustain discharge intensity, a highly reliable AC type It is possible to realize a driving method of Ma display panel.
[Brief description of the drawings]
FIG. 1 is a waveform diagram showing an operation waveform of a main part in a driving method of a plasma display panel according to an embodiment of the present invention. FIG. 2 shows a conventional driving waveform and a write discharge waveform when the driving waveform of the present invention is used. FIG. 3 is an explanatory diagram showing a distribution state of wall charges when a conventional driving waveform is used. FIG. 4 is an explanatory diagram showing a distribution state of wall charges when a driving waveform is used in the present invention. FIG. 5 is a waveform diagram showing an example of a voltage waveform that changes continuously or intermittently in the present invention. FIG. 6 is a waveform diagram showing an example of a voltage waveform that changes continuously or intermittently in the present invention. FIGS. 8A and 8B are cross-sectional views of an AC type plasma display panel. FIG. 9 is a cross-sectional view of an AC type plasma display panel according to a conventional driving method. Operating wave Waveform diagram showing EXPLANATION OF REFERENCE NUMERALS
1 Panel 7 Scan electrode 8 Sustain electrode 9 Address electrode

Claims (1)

A front substrate provided with an electrode group comprising scan electrodes and sustain electrodes arranged in parallel with each other; and a rear substrate provided with a plurality of address electrodes arranged in parallel with each other in a direction perpendicular to the scan electrodes and sustain electrodes. An AC type plasma display panel is formed by disposing the front substrate and the rear substrate opposite to each other with a discharge space therebetween, and one field is formed by a plurality of subfields having an address period and a sustain period. A method for driving an AC type plasma display panel in which the entire surface initialization operation performed on all the pixels of the panel is limited to a part of subfields, and at the end of the sustain period, a pulse in which the sustain electrode side becomes an anode. After applying a voltage to cause a sustain discharge, an upward ramp waveform with the scan electrode side serving as an anode is applied to cause a discharge. , The subsequent initialization operations, after the application of ramp voltage waveform of the uplink, the driving method of the AC type plasma display panel, characterized in that immediately applying a ramp voltage waveform of the downlink.

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