JP2006003633A - Plasma display device and driving method used for plasma display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display device which is lowered in the luminance of black display and is enhanced with a contrast ratio by solving the problem that the luminance of the black display is high due to light emission of pre-discharge and pre-elimination discharge. <P>SOLUTION: A pre-discharge region is completely restricted by a region sandwiched by a scanning main electrode 22 and a sustaining main electrode 24 and the discharge light emission in the above region is shielded by respective bus electrodes 22a and 24a annexed to the scanning main electrode 22 and the sustaining main electrode 24. Therefore, the greater part of the light emission by the pre-discharge is prevented from emitting to the display surface side and the black luminance due to the light emission by the pre-discharge is extremely reduced. The contrast ratio is thus greatly improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 use in improving the contrast ratio of a display screen and a 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. In the PDP, the display electrode (a pair of surface discharge electrodes composed of a scan electrode and a sustain electrode) is exposed to the discharge space and operates in a DC discharge state according to the structural classification, and the same electrode is placed in the discharge space. There is an AC type that is not directly exposed but is covered with a dielectric and operates indirectly in an AC discharge state. Further, the AC type includes a memory operation type that uses a memory function based on the charge storage action of the dielectric and a refresh operation type that does not use the memory function.

Conventionally, for example, as shown in FIG. 16, the PDP used in the memory operation type plasma display device is m pieces arranged parallel to each other in the row direction H on the inner surface of a front substrate (not shown) in the display panel 1. Of the scanning electrode 2 (S _i , i = 1, 2,..., M) and the sustain electrode 3 (C _i , i = 1, 2,..., M), and a back substrate (not shown) On the inner surface, n data electrodes 4a and 4b (D _j , j = 1, 2,..., N) arranged along the column direction V so as to be orthogonal to the same-surface discharge electrode group are arranged. Then, one unit cell 5 (hereinafter also simply referred to as “cell”) is formed in each of the intersecting regions of the surface discharge electrode group and the data electrodes 4a and 4b, and the cell group is formed in a matrix in the row direction H and the column direction V. Is arranged. 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. 17 is a plan view of the unit cell 5 in FIG.
In the unit cell 5, as shown in FIG. 17, the scan electrode 2 and the sustain electrode 3 are arranged above the partition wall 7 with a discharge gap 6 therebetween. A bus electrode 2 a is disposed on the opposite side of the discharge gap 6 side on the scan electrode 2, and a bus electrode 3 a is disposed on the opposite side of the discharge electrode 6 on the sustain electrode 3.

18 is a cross-sectional view taken along line AA of the unit cell 5 of FIG.
In the unit cell 5, the front substrate 11 and the rear substrate 12 are arranged to face each other with a predetermined interval. The front substrate 11 is made of a glass substrate or the like, and the scan electrode 2 and the sustain electrode 3 are disposed on the front substrate 11 with a discharge gap 6 therebetween. The scan electrode 2 and the sustain electrode 3 are made of transparent electrodes such as ITO (Indium Tin Oxide, transparent conductive thin film), and are provided with metal bus electrodes 2a and 3a for lowering the line resistance. A transparent dielectric layer 13 is formed on these electrodes, and a protective layer 14 is formed on the transparent dielectric layer 13. The protective layer 14 is made of MgO or the like, and protects the transparent dielectric layer 13 from discharge.

  On the other hand, the back substrate 12 is formed of a glass substrate or the like, and the data electrodes 4 a and 4 b are provided on the back substrate 12 so as to be orthogonal to the scan electrodes 2 and the sustain electrodes 3. Further, a white dielectric layer 15 is provided on the data electrodes 4a and 4b, and a phosphor layer 16 is provided on the white dielectric layer 15 for converting ultraviolet light generated by discharge into visible light. ing. A color display PDP is obtained by coating the phosphor layer 16 for each unit cell, for example, red (R), green (G), and blue (B). Between the front substrate 11 and the back substrate 12, a grid-like partition wall 7 is formed so as to surround each unit cell 5. The partition wall 7 serves to secure the discharge space 17 and partition the pixels. In the discharge space 17, a mixed gas such as He, Ne, and Xe is sealed as a discharge gas.

FIG. 19 is a diagram for explaining the principle of the gradation display method used in the PDP of FIG. 16, in which the horizontal axis represents time, and the vertical axis represents the number of scanning electrodes in the PDP.
In this PDP, as shown in FIG. 19, four subfields SF1, SF2 in which one field TF, which is a period for displaying one screen (for example, 1/60 second), is weighted based on the gradation level. , SF3, and SF4, and each subfield is divided into a preliminary discharge period T1, a scanning period T2, a sustain period T3, and a sustain erase period T4. 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 scan pulse and the data pulse applied to the data electrodes 4a and 4b 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. 19, since the length of each sustain period T3 of the subfields SF1, SF2, SF3, and SF4 is set to a ratio of 1: 2: 4: 8, the light emission in these sustain periods T3 is combined. , A screen with 16 gradations (0 to 15) is displayed. For example, when a nine-gradation screen is displayed, the subfield SF1 (gradation; 1) and the subfield SF4 (gradation; 8) are controlled to emit light during the period of one field TF. In general, when one field is divided into n SFs and the luminance ratio for each subfield is set to 1 (= 2 ⁰ ): 2 (= 2 ¹ ):...: 2 ⁿ⁻² : 2 ^{n−1 2n} gradation display is possible.

FIG. 20 is a diagram showing drive waveforms applied to each electrode in each subfield in FIG.
In each subfield, as shown in FIG. 20, in the preliminary discharge period T1, the first preliminary discharge pulse da having a negative polarity as viewed from the sustain electrode reference potential is applied to the sustain electrode 3, and the scan electrode reference potential is applied to the scan electrode 2 from the scan electrode reference potential. As a result, a positive second pre-discharge pulse db is applied, a potential difference exceeding the discharge start voltage is applied between sustain electrode 3 and scan electrode 2, and all unit cells are forcibly discharged. The first preliminary discharge pulse da has a rectangular wave shape in which the voltage changes steeply at both the leading edge and the trailing edge. The second preliminary discharge pulse db has an inclined wave shape whose leading edge changes gently. The rate of change of the leading edge is set to be smaller than 10 (V / μs).

  Thereafter, a negative preliminary erasing discharge pulse e as viewed from the scanning electrode reference potential is applied to the scanning electrode 2, and all unit cells are forcibly discharged again. The preliminary erasing discharge pulse e has an inclined wave shape whose leading edge changes gently. The rate of change of the leading edge is set to be smaller than 10 (V / μs). The discharge operation by the preliminary discharge pulses da and db is called preliminary discharge, and the discharge operation by the preliminary erase discharge pulse is called preliminary erase discharge. By this preliminary erasing discharge, the wall charge distribution is adjusted, and the occurrence of erroneous discharge due to the application of another drive pulse that follows is prevented. In addition, by performing preliminary discharge and preliminary erasing discharge, the active particle density in each unit cell 5 is increased, and the reaction rate during the subsequent address discharge is improved.

After the preliminary discharge and the preliminary erasure discharge, the scanning pulse f is applied to the scanning electrodes S ₁ ,..., S _m at different timings in the scanning period T2. The scan pulse f is negative in view of the scan electrode reference potential. The display data pulse g is applied to the data electrodes D ₁ ,..., D _n according to the display information in accordance with the timing when the scanning pulse f is applied. The display data pulse g is positive in view of the data electrode reference potential. The hatched lines in the display data pulse g indicate that the presence or absence of the display data pulse g is determined based on the presence or absence of display information for the corresponding cell. In the unit cell 5 to which the display data pulse g is applied when the scan pulse f is applied, a discharge is generated in the discharge space 17 between the scan electrode 2 and the data electrodes 4a and 4b. When no data pulse g is applied, no discharge occurs. This discharge causes display information to be written in each unit cell, which is called address discharge.

  Further, in this address discharge, a discharge between the scan electrode 2 and the sustain electrode 3 may be induced by using a discharge between the scan electrode 2 and the data electrodes 4a and 4b as a trigger. In order to generate this discharge stably, a positive bias potential (that is, sub-scanning pulse p) is applied to sustain electrode 3 with respect to sustain electrode reference potential, and scan electrode 2 and sustain electrode 3 at the time of address discharge The potential difference may be increased. Further, in order to reduce the amplitude of the scan pulse f, a negative bias potential (that is, the scan base pulse q) is applied to the scan electrode 2 from the scan electrode reference potential over almost the entire scan period T2, and the amount of displacement is reduced. Only the scan pulse f may be applied. In the unit cell 5 in which the address discharge has occurred, positive wall charges are accumulated in the transparent dielectric layer 13 on the scan electrode 2. At this time, negative wall charges are accumulated in the white dielectric layer 15 on the data electrodes 4a and 4b.

  Thereafter, in the sustain period T3, the positive potential due to the positive wall charges formed in the transparent dielectric layer 13 and the first negative sustain pulse ha applied to the sustain electrode 3 are superposed, thereby The first discharge occurs. Further, if a discharge between the scan electrode 2 and the sustain electrode 3 is also induced during the address discharge, a negative wall charge is also formed in the transparent dielectric layer 13 on the sustain electrode 3 by the address discharge. The first sustain pulse is caused by the positive potential due to the positive wall charge formed on the transparent dielectric layer 13 on the scan electrode 2 and the negative wall charge formed on the transparent dielectric layer 13 on the sustain electrode 3. A negative potential is superimposed and a first discharge is generated. When the first discharge occurs, positive wall charges are accumulated in the transparent dielectric layer 13 on the sustain electrodes 3 and negative wall charges are accumulated in the transparent dielectric layer 13 on the scan electrodes 2. The second sustain pulse hb applied to the scan electrode 2 is superimposed on the potential difference due to these wall charges, and a second discharge is generated.

  Thereafter, similarly, the potential difference due to the wall charges formed by the nth discharge and the (n + 1) th sustain pulse are superimposed to maintain the discharge. For this reason, this discharge operation is called sustain discharge. The magnitude of the brightness of the display screen is controlled by the number of sustain discharges. Further, if the voltages of the sustain pulses ha and hb are adjusted in advance to such an extent that no discharge is generated only by applying these pulses, the first sustain pulse is supplied to the unit cell 5 in which no address discharge has occurred. Since there is no potential due to wall charges before application of ha, even if the sustain pulse ha is applied, the first sustain discharge does not occur, and therefore no subsequent sustain discharge occurs. After the sustain pulses ha and hb are applied, in the sustain erasing period T4, the unit cell 5 in which the sustain discharge is maintained by applying the negative sustain erasing pulse k to all the scan electrodes 2 from the scan electrode reference potential. Discharge occurs and the wall charge distribution is initialized. The sustain erasing pulse k has an inclined wave shape whose leading edge changes gently, and the rate of change of the leading edge is set smaller than 10 (V / μs). The discharge operation by the sustain erase pulse k is called sustain erase discharge.

  In the conventional plasma display device as described above, when all the subfields are not selected, even when the luminance ratio of the display screen is “0”, that is, black display, all the unit cells 5 in the preliminary discharge period T1 of each subfield. Emits preliminary discharge light. Since this preliminary discharge light emission is weaker than the sustain discharge light emission, the luminance in black display is smaller than the luminance when the number of sustain discharges is large. However, when the plasma display device is used in a dark environment or when a dark image is displayed, the luminance in black display is a factor that degrades the quality of the display screen. As an index representing the quality of such a display screen, there is a display contrast ratio (maximum luminance / minimum luminance) which is a ratio between the maximum luminance and the minimum luminance (that is, black luminance). Clear indication is possible.

As a technique for improving the contrast ratio, conventionally, for example, there are techniques described in the following documents.
In the plasma display device described in Patent Document 1 ("Plasma Display Panel Driving Method" in Patent Document 1), a so-called "thinning" technique is used to generate a preliminary discharge only in a predetermined unit cell for each subfield. The minimum luminance, that is, the black display luminance is lowered, and the contrast ratio is improved.

In the plasma display device described in Patent Document 2, the bus electrode is installed in the vicinity of the discharge gap, and the transparent electrode is provided with an opening, so that the preliminary discharge region is limited to the installation range of the bus electrode. Most of the light emission is shielded by the bus electrode. Both the maximum luminance and the black luminance are reduced, but the degree of reduction in black luminance is greater than the degree of reduction in maximum luminance, and the contrast ratio is improved.
JP-A-8-2221036 (abstract, FIG. 1) JP 2002-298742 A (first page, FIG. 2, FIG. 26)

However, the conventional plasma display device has the following problems.
That is, the plasma display device of FIG. 16 has a problem in that the light emission luminance in black display is large and the display contrast ratio is small.

  Further, in the plasma display device described in Patent Document 1, the preliminary discharge is thinned out in order to reduce the black display luminance. However, the preliminary discharge is not performed in the subfield and the unit cell where the preliminary discharge is not performed. The occurrence of address discharge becomes unstable compared to the subfields and unit cells, and proper image display may not be performed. In particular, in unit cells in which preliminary discharges are thinned out continuously in a plurality of subfields, the instability of the address discharge becomes more prominent, causing flickering in the image and non-lighting cells. There is.

  In the plasma display device described in Patent Document 2, the contrast ratio is improved by increasing the degree of reduction in black luminance more than the degree of reduction in maximum luminance. Since the difference from the reduction rate of black luminance is small, there is a problem that the effect of improving the contrast ratio is small. The reason for this is that even if the bus electrode is arranged in the vicinity of the discharge gap and an opening is provided in the transparent electrode, the preliminary discharge region is in the opening of the transparent electrode, and depending on the conditions, the electrode near the non-discharge gap that exceeds the opening This is because the preliminary discharge region cannot be limited to a small region.

  In order to solve the above-mentioned problems, the invention described in claim 1 divides a plasma display panel and a field of the display screen into a plurality of subfields weighted based on a gradation level. The plasma display panel includes a first substrate and a second substrate disposed opposite to each other, and the second substrate of the first substrate. A plurality of main electrode pairs, which are provided on a surface facing the substrate and are arranged parallel to each other with a discharge gap therebetween, and the second substrate of the first substrate are opposed to the second substrate. A scan extension electrode provided on a surface of the scan main electrode at a predetermined interval on the opposite side of the discharge gap, and the discharge main electrode with respect to the sustain main electrode. A plurality of extended electrode pairs made of sustain extended electrodes provided on the opposite side of the substrate at a predetermined interval, and the main electrode pairs and the respective electrode pairs on the surface of the second substrate facing the first substrate. A plurality of data electrodes provided in a manner intersecting with the extended electrode pair, and a plurality of main electrodes and a plurality of extended electrode pairs and a plurality of data electrodes formed in a crossing region between the plurality of data electrodes and surrounded by a partition wall A unit cell; a discharge space formed by sealing a discharge gas between the first substrate and the second substrate; and the scan main electrode and the sustain main electrode. And a light shielding means for shielding most of the light emission in the sub-field, and the driving means maintains a pre-discharge pulse for performing a pre-discharge for all the unit cells for each of the subfields and the main scanning electrode. While applied only to the main electrode, the front Selected by applying a display pulse in synchronization with the scan pulse to each data electrode at the same time as applying a scan pulse to each scan main electrode in a line-sequential manner without applying to the scan extension electrode and the sustain extension electrode An address discharge is generated in the unit cell, and all or most of the sustain pulses are alternately applied to the scan extension electrode and the sustain extension electrode to generate a sustain discharge in each selected unit cell. It is characterized by that.

  The invention according to claim 2 relates to the plasma display device according to claim 1, wherein the driving means applies the sustain pulse to the scan extension electrode and the sustain extension electrode simultaneously with the scan main electrode and the sustain main electrode. Further, the sustain pulse is applied.

  A third aspect of the present invention relates to the plasma display device according to the first or second aspect, wherein the scanning main electrode or the sustaining main electrode is configured by laminating a transparent electrode and a metal bus electrode, and the scanning main electrode The width of the bus electrode attached to the electrode or the maintenance main electrode is set to be smaller than the width of the corresponding transparent electrode and more than half of the width of the transparent electrode, and the bus electrode constitutes the light shielding means It is characterized by doing.

  A fourth aspect of the present invention relates to the plasma display device according to the first or second aspect, wherein the scanning main electrode or the sustaining main electrode is formed only by a metal bus electrode, and the bus electrode constitutes the light shielding unit. It is characterized by doing.

  A fifth aspect of the present invention relates to the plasma display device according to the first, second, third, or fourth aspect of the present invention, and a black dielectric that blocks light emitted from the scanning main electrode and the sustaining main electrode in a region including at least the discharge gap. It is characterized in that a layer is provided.

  A sixth aspect of the present invention relates to the plasma display device according to the first, second, third, fourth, or fifth aspect, wherein the two scan extension electrodes belonging to the unit cell adjacent in the vertical direction or the two sustaining electrodes. At least one of the extended electrodes is electrically connected and integrated.

  The invention according to claim 7 relates to the plasma display device according to claim 6, wherein the two scan extension electrodes that are electrically connected and integrated, or the central part of the two sustain extension electrodes, One bus electrode is formed.

  The invention according to claim 8 relates to the plasma display device according to claim 7, wherein the two scan extension electrodes that are electrically connected and integrated, or the two sustain extension electrodes are the unit cell. It is electrically connected through a connecting portion that passes through the center line.

  The invention according to claim 9 relates to the plasma display device according to claim 7, wherein the two scan extension electrodes that are electrically connected and integrated, or the two sustain extension electrodes are the unit cell. It is electrically connected through a connecting portion formed on a partition wall that surrounds.

  The invention described in claim 10 includes a plasma display panel and driving means for driving the plasma display panel by dividing one field of the display screen into a plurality of subfields weighted based on the gradation level. The plasma display panel is opposed to the second substrate of the first substrate and the second substrate disposed opposite to each other, and the plasma display panel is opposed to the second substrate of the first substrate. A plurality of main electrode pairs each consisting of a scanning main electrode and a sustaining main electrode facing each other in parallel with each other across a discharge gap, and a surface of the first substrate facing the second substrate, A scan extension electrode provided on the opposite side of the discharge gap with respect to the scan main electrode at a predetermined interval, and the discharge gap with respect to the sustain main electrode A plurality of extended electrode pairs made of sustain extended electrodes provided on the opposite side at a predetermined interval, and each main electrode pair and each extended electrode on the surface of the second substrate facing the first substrate A plurality of unit cells formed by being surrounded by partition walls in a plurality of data electrodes provided in a mode of intersecting with a pair, and intersecting regions of the plurality of main electrode pairs, the plurality of extended electrode pairs, and the plurality of data electrodes A discharge space formed by sealing discharge gas between the first substrate and the second substrate, and light emission in the scan main electrode and the sustain main electrode And a light shielding means for shielding most of the light, and for each subfield, a preliminary discharge pulse for performing preliminary discharge for all the unit cells is applied only to the scanning main electrode and the sustaining main electrode. While applying the scanning extension voltage And the unit cell selected by applying a display data pulse synchronized with the scan pulse to each data electrode at the same time as applying a scan pulse to each scan main electrode in a line-sequential manner without applying to the sustain extension electrode The address discharge is generated, and all or most of the sustain pulses are alternately applied to the scan extension electrode and the sustain extension electrode to generate the sustain discharge in each of the selected unit cells.

  According to the configuration of the present invention, for each subfield, a preliminary discharge pulse for performing preliminary discharge for all unit cells is applied only to the scanning main electrode and the sustaining main electrode, while the scanning expansion electrode and the sustaining expansion are applied. An address discharge is generated in the selected unit cell by applying a display data pulse synchronized with the scanning pulse to each data electrode at the same time as applying a scanning pulse to each scanning main electrode line-sequentially without applying to the electrodes, All or most of the sustain pulses are alternately applied to the scan extension electrode and the sustain extension electrode to generate a sustain discharge in each of the selected unit cells, and most of the light emission at the scan main electrode and the sustain main electrode Therefore, the preliminary discharge region is completely limited to the region sandwiched between the scanning main electrode and the sustaining main electrode, and discharge light emission in the region is blocked. Because it is shielded by means, most of the light emission by the priming discharge is not emitted to the display surface side, the black luminance caused by the emission of light by the preliminary discharge becomes very small, it can be greatly improved contrast ratio.

  Further, since the discharge gap portion is shielded from light by the black dielectric layer, almost all light emission by the preliminary discharge is shielded. Thereby, the black luminance due to the light emission luminance in the preliminary discharge becomes so small that it cannot be visually recognized, and the contrast ratio of the display screen is further improved. In addition, since most of the scan main electrode and sustain main electrode regions are shielded from light by the black dielectric layer, it is not necessary to increase the width of the bus electrode to the same width as the scan main electrode and sustain main electrode for light shielding. . For this reason, only the electrode resistance needs to be considered for the width of the bus electrode, so that the degree of freedom in design can be increased. Further, when the black dielectric layer is provided only in the discharge gap region, the formation region of the black dielectric layer becomes narrow, and the material can be reduced.

  In addition, since at least one of the two scan extension electrodes belonging to the upper and lower adjacent unit cells or the two sustain extension electrodes is electrically connected and integrated, it can be connected to the scan extension electrode. Terminals can be reduced. In addition, since one bus electrode is formed at the central portion of the two integrated scanning extension electrodes or the two sustain extension electrodes, the influence of blocking the sustain discharge light emission is suppressed and maintained. The extraction efficiency of discharge light emission can be improved. Also, the two scanning extension electrodes that are electrically connected and integrated, or the two sustaining extension electrodes are electrically connected via a connecting portion formed on the partition wall that surrounds the unit cell. As a result, the influence of blocking the sustain discharge light emission is suppressed, and the extraction efficiency of the sustain discharge light emission can be improved.

  Provided is a plasma display device in which the preliminary discharge region is limited to a narrow range and the luminance of the preliminary discharge is reduced to reduce the black luminance, thereby improving the contrast ratio and obtaining a high-quality display screen.

FIG. 1 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.
As shown in the figure, the plasma display device of this example includes a display panel (PDP) 21, data drivers 31a and 31b, a scanning main electrode driver 32, a scanning expansion electrode driver 33, and a sustaining main electrode driver 34. The sustain extension electrode driver 35, an A / D (analog / digital) conversion circuit 41, a pixel conversion circuit 42, a subfield conversion circuit 43, a controller 44, and a power supply circuit 45.

  The display panel 21 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 scanning main electrode 22 and the sustaining main electrode 24 are arranged in parallel to each other with a discharge gap (not shown). These scanning main electrode 22 and sustaining main electrode 24 constitute a main electrode pair. Further, a scanning extension electrode 23 is provided on the opposite side of the discharge gap with respect to the scanning main electrode 22 at a predetermined interval, and at a predetermined interval on the opposite side of the discharge gap with respect to the sustaining main electrode 24. A maintenance expansion electrode 25 is provided. These scan extension electrode 23 and sustain extension electrode 25 constitute an extension electrode pair. A plurality of data electrodes 26a and 26b are provided on the surface of the rear substrate facing the front substrate so as to intersect with the main electrode pairs and the extended electrode pairs. A unit cell 27 is formed in each intersecting region of the plurality of main electrode pairs and the plurality of extended electrode pairs and the plurality of data electrodes 26a and 26b.

  The data driver 31a applies a display data pulse and an erase data pulse corresponding to the display data w to the data electrode 26a. The data driver 31b applies a display data pulse and an erase data pulse corresponding to the display data w to the data electrode 26b. The scanning main electrode driver 32 applies a preliminary discharge pulse, a preliminary erasing discharge pulse, a scanning pulse, a sustaining pulse, and a sustaining erasing pulse to the scanning main electrode 22. The scan extension electrode driver 33 applies a sustain pulse and a sustain erase pulse to the scan extension electrode 23. The sustain main electrode driver 34 applies a preliminary discharge pulse and a sustain pulse to the sustain main electrode 24. The sustain extension electrode driver 35 applies a sustain pulse to the sustain extension electrode 25.

  The A / D conversion circuit 41 converts the analog video signal in into a digital video signal u. The pixel conversion circuit 42 converts the number of pixels of the video signal u into the number of pixels of the display panel (PDP) 21 that is the number of pixels to be actually displayed, and generates the video signal v. The subfield conversion circuit 43 converts one field of the video signal v from the pixel conversion circuit 42 into display data w for each subfield and sends it to the data drivers 31a and 31b. This one field is divided into, for example, four subfields SF1, SF2, SF3, and SF4 weighted based on the gradation level as in the conventional FIG.

  The controller 44 controls the operation timing of the data drivers 31a and 31b, the scanning main electrode driver 32, the scanning expansion electrode driver 33, the sustaining main electrode driver 34, and the sustaining expansion electrode driver 35. For each field, a preliminary discharge pulse for performing preliminary discharge on all the unit cells 27 is applied only to the scan main electrode 22 and the sustain main electrode 24, while not applied to the scan extension electrode 23 and the sustain extension electrode 25. First, a scanning pulse is applied to each scanning main electrode 22 line-sequentially, and simultaneously, a display data pulse synchronized with the scanning pulse is applied to each data electrode 26a, 26b, thereby generating an address discharge in the selected unit cell 27. Then, all or most of the sustain pulses are alternately applied to the scan extension electrode 23 and the sustain extension electrode 25 to select the above. And generating a sustain discharge in each unit cell 27. Further, when applying the sustain pulse to the scan extension electrode 23 and the sustain extension electrode 25, the controller 44 simultaneously applies the sustain pulse to the scan main electrode 22 and the sustain main electrode 24. The power supply circuit 45 supplies predetermined high voltage power to the data drivers 31 a and 31 b, the scanning main electrode driver 32, the scanning extended electrode driver 33, the sustaining main electrode driver 34, and the sustaining extension electrode driver 35. A timing signal (horizontal synchronization signal, vertical synchronization signal) t is input to the A / D conversion circuit 41, the pixel conversion circuit 42, the subfield conversion circuit 43, and the controller 44. The operation of each of these circuits, the display screen, Take the synchronization.

FIG. 2 is a diagram in which the PDP 21 in FIG. 1 is extracted.
In this PDP 21, as shown in FIG. 2, m scanning main electrodes 22 (S _i , i = 1, 2,..., M), sustain main electrodes 24, and scanning extended electrodes are formed on the inner surface of a front substrate (not shown). 23 and the sustain expansion electrode 25 are arranged in parallel to each other in the row direction H. Further, the data electrode 26a (D _j , j = 1, 3,..., N−1) and the data electrode 26b are arranged on the inner surface of the rear substrate (not shown) along the column direction V so as to be orthogonal to the scanning main electrode 22 and the like. (D _j , j = 2, 4,..., N) are arranged. A unit cell 27 is formed in each crossing region of the data electrodes 26a, 26b and the scanning main electrode 22, and a group of cells are arranged in a matrix in the row direction H and the column direction V.

FIG. 3 is a plan view showing the configuration of the unit cell 27 in FIG.
As shown in FIG. 3, the unit cell 27 is formed by being surrounded by a grid-like partition wall 28, and the scanning main electrode 22 and the sustain main electrode 24 are arranged above the partition wall 28 with a discharge gap 29 therebetween. ing. The scanning main electrode 22 is configured by laminating a metal bus electrode 22a on a transparent electrode, and the width of the bus electrode 22a is smaller than the width of the corresponding transparent electrode and more than half of the width of the transparent electrode. The bus electrode 22a shields most of the light emitted from the scanning main electrode 22 and the sustaining main electrode 24. The bus electrode 22a has a function of reducing the line resistance of the scanning main electrode 22. Similarly, the sustain main electrode 24 is configured by laminating a metal bus electrode 24 a on a transparent electrode, and the bus electrode 24 a shields most of light emission from the scan main electrode 22 and the sustain main electrode 24. Further, the bus electrode 24 a has a function of reducing the line resistance of the sustain main electrode 24. Further, the scanning extension electrode 23 and the sustain extension electrode 25 are disposed on the upper side of the partition wall 28. A bus electrode 23a is arranged on the scanning extension electrode 23 on the opposite side of the scanning main electrode 22 side, and a bus electrode 25a is arranged on the maintenance extension electrode 25 on the opposite side of the maintenance main electrode 24 side. The bus electrode 23a has a function of reducing the line resistance of the scanning extension electrode 23. The bus electrode 25a serves to lower the line resistance of the sustain extension electrode 25.

4 is a cross-sectional view taken along line AA in FIG.
In the unit cell 27, as shown in FIG. 4, a front substrate 51 and a back substrate 52 are arranged facing each other with a predetermined interval. The front substrate 51 is composed of a glass substrate or the like, and the scanning main electrode 22, the scanning extension electrode 23, the maintenance main electrode 24, and the maintenance extension electrode 25 are disposed on the front substrate 51. The scan main electrode 22, the scan extension electrode 23, the sustain main electrode 24, and the sustain extension electrode 25 are made of transparent electrodes such as ITO (Indium Tin Oxide, transparent conductive thin film), and are made of a metal bus for reducing the line resistance. Electrodes 22a, 23a, 24a, and 25a are attached to each. A transparent dielectric layer 53 is formed on these electrodes, and a protective layer 54 is formed on the transparent dielectric layer 53. The protective layer 54 is made of MgO or the like, and protects the transparent dielectric layer 53 from discharge.

  On the other hand, the back substrate 52 is formed of a glass substrate or the like, and the data electrodes 26a and 26b are provided on the back substrate 52 so as to be orthogonal to the scanning main electrode 22 and the like. Further, a white dielectric layer 55 is provided on the data electrodes 26a and 26b, and a phosphor layer 56 for converting ultraviolet light generated by the discharge into visible light is provided on the white dielectric layer 55. ing. A color display PDP is obtained by coating the phosphor layer 56 for each unit cell, for example, red (R), green (G), and blue (B). Between the front substrate 51 and the back substrate 52, a cross-shaped partition wall 28 is formed so as to surround the unit cell 27. The barrier ribs 28 serve to secure the discharge space 57 and partition the pixels. A mixed gas such as He, Ne, and Xe is sealed in the discharge space 57 as a discharge gas.

FIG. 5 is a voltage waveform diagram of each part for explaining the operation of the plasma display device of FIG.
With reference to this figure, the processing content of the drive method used for the plasma display device of this example will be described.
In this driving method, for each subfield, a preliminary discharge pulse for performing preliminary discharge on all the unit cells 27 is applied only to the scanning main electrode 22 and the sustaining main electrode 24, while the scanning extension electrode 23 and It is not applied to the sustain expansion electrode 25. Thereafter, a scanning pulse is applied to each scanning main electrode 22 (S _i , i = 1, 2,..., M) line-sequentially, and at the same time, a display data pulse synchronized with the scanning pulse is applied to each data electrode 26a, 26b. Is applied to the selected unit cell 27, and all or most of the sustain pulses are alternately applied to the scan extension electrode 23 and the sustain extension electrode 25. Sustain discharge occurs.

  That is, in the preliminary discharge period T1, a negative first preliminary discharge pulse da is applied to the sustain main electrode 24, and a positive second preliminary discharge pulse db is applied to the scan main electrode 22, and the sustain main electrode 24 and the scan main electrode 24 are scanned. A potential difference exceeding the discharge start voltage is applied between the main electrode 22 and all cells are forcibly discharged. At this time, since the preliminary discharge pulse is not applied to the sustain extension electrode 25 and the scan extension electrode 23, the preliminary discharge area is an area sandwiched between the sustain main electrode 24 and the scan main electrode 22 (the sustain main electrode 24 and the scan extension electrode 23). (Including the main electrode 22) and does not expand in the direction of the sustain extension electrode 25 and the scan extension electrode 23 at all. Thereafter, a negative preliminary erasing discharge pulse e is applied to the scanning main electrode 22, and all the cells are forcibly discharged again. Since the preliminary erasure discharge pulse e is not applied to the scan extension electrode 23 and no preliminary discharge is generated at the portion of the scan extension electrode 23, the preliminary erasure discharge does not spread in the direction of the scan extension electrode 23.

In the scanning period T2, a negative scanning pulse f is applied to the scanning main electrode 22 (S _i , i = 1, 2,..., M) line-sequentially. In FIG. 5, the waveform of the scanning pulse f for one arbitrary scanning line is shown. Further, in synchronization with the timing of the scanning pulse f is applied, the data electrodes D _1, D _2, ..., the display data pulse g of positive polarity corresponding to the display information D _n is applied. The diagonal lines in the display data pulse g indicate that the presence or absence of the display data pulse g is determined based on the presence or absence of display information for the corresponding cell. In the unit cell 27 to which the display data pulse g is applied when the scanning pulse f is applied, an address discharge is generated in the discharge space 57 between the scanning main electrode 22 and the data electrodes 26a and 26b. If the display data pulse g is not applied, no address discharge occurs. This address discharge is an address discharge in which display information is written in each unit cell 27. In the unit cell 27 in which the address discharge has occurred, positive wall charges are accumulated in the transparent dielectric layer 53 on the scanning main electrode 22, and negative wall charges are accumulated in the white dielectric layer 55 on the data electrodes 26a and 26b. .

  In the sustain period T3, the positive potential due to the positive wall charges formed on the transparent dielectric layer 53 on the scan main electrode 22 and the negative first sustain pulse ha applied to the sustain main electrode 24 are superimposed. As a result, the first sustain discharge occurs. At this time, since the sustain pulse ha is also applied to the sustain expansion electrode 24, the first sustain discharge spreads to the sustain expansion electrode 24. As a result of the first sustain discharge, a positive wall charge is applied to the transparent dielectric layer 53 on the sustain main electrode 24 and the sustain extended electrode 25, and a negative wall charge is applied to the transparent dielectric layer 53 on the scan main electrode 22. Accumulated. The second sustain pulse hb applied to the scanning main electrode 22 is superimposed on the potential difference due to these wall charges, and a second sustain discharge is generated. At this time, since the sustain pulse hb is also applied to the scan extension electrode 25, the second sustain discharge spreads to the scan extension electrode 25, and the negative voltage is also applied to the transparent dielectric layer 53 on the scan extension electrode 25. Wall charges are accumulated. Thereafter, the scanning main electrode 22 and the scanning extension electrode 23 simultaneously act in the same manner as the conventional scanning electrode, and the sustaining main electrode 24 and the sustaining extension electrode 25 simultaneously act in the same manner as the conventional sustaining electrode and maintain. Discharge continues.

  In the sustain erasing period T4, after the sustain pulses ha and hb are applied, the negative sustain erasure pulse k is applied to all the scan main electrodes 22 and the scan extension electrodes 23, and the sustain discharge is maintained in the unit cell 27. When the erasing discharge is generated, the wall charges are reset.

  In the prior art, the preliminary discharge region is a wide region sandwiched between the scan electrode and the sustain electrode and including both electrodes. In this embodiment, the preliminary discharge region is the scan main electrode 22 and the sustain main electrode 24. It is completely limited to the area between the two. In addition, the sustain discharge region extends to a region sandwiched between the scan extension electrode 23 and the sustain extension electrode 25. Discharge light emission in a region sandwiched between the scanning main electrode 22 and the sustaining main electrode 24, which is a preliminary discharge region, is shielded by the bus electrodes 22a and 24a attached to the scanning main electrode 22 and the sustaining main electrode 24, respectively. For this reason, most of the light emission by the preliminary discharge is not emitted to the display surface side, and the black luminance resulting from the preliminary discharge light emission is much smaller than that of the prior art.

  In the sustain discharge, the light emission in the region sandwiched between the scan main electrode 22 and the sustain main electrode 24 is shielded in the same manner as the preliminary discharge, but the light emission in the region extending to the scan extension electrode 23 and the sustain extension electrode 25 is shielded. Therefore, when the entire unit cell 27 is viewed, the reduction rate from the light emission luminance of the sustain discharge in the conventional technique is small. Thus, in this embodiment, the reduction rate of the preliminary discharge light emission luminance is overwhelmingly larger than the reduction rate of the light emission luminance of the sustain discharge, and is estimated by (sustain discharge light emission luminance) ÷ (preliminary discharge light emission luminance). The contrast ratio that can be increased.

FIG. 6 is a diagram for explaining the result of improving the contrast ratio.
As shown in the figure, the contrast ratio is 421 in the conventional technique shown in FIG. 17, 529 in the conventional technique shown in Patent Document 2, and 1007 in the embodiment shown in FIG. In particular, the preliminary discharge luminance is 2.27 cd / m ² in Patent Document 2, but is 1.16 cd / m ² in this embodiment, which is significantly reduced.

  In order to increase the contrast ratio, the preliminary discharge region is limited to a smaller region, and the degree of light shielding in the limited preliminary discharge region is increased. For example, a region (including both main electrodes) sandwiched between the scanning main electrode 22 and the sustaining main electrode 24 is reduced, and the scanning main electrode 22 and the sustaining main electrode 24 mostly overlap with the light-shielding bus electrode. What is necessary is just composition. In this case, as an ultimate form, it is conceivable that the scanning main electrode 22 and the sustaining main electrode 24 made of transparent electrodes are deleted, and an electrode corresponding to the main electrode is formed only with the corresponding metal bus electrodes. However, in a process in which the bus electrode is made of, for example, thick film Ag, the smoothness of the edge of the bus electrode is poor, so that it is difficult to control the discharge gap that is formed between the bus electrodes as designed. is there.

  For this reason, it is preferable to form a discharge gap with transparent electrodes having good edge smoothness, and the bus electrode has a narrower width than the transparent electrode and is provided on the transparent electrode. The reason why the bus electrode is narrower than the transparent electrode is to allow for a misalignment margin when the bus electrode is formed on the transparent electrode. This margin is designed to be about ± 20 μm in the worst case with reference to the formation of thick Ag layer by screen printing, and the bus electrode width should be 40 μm narrower than the transparent electrode width and be installed on the same central axis. For example, even if the position is shifted, the bus electrode does not protrude from the transparent electrode. However, if the misalignment margin can be improved by using other process technology, the bus electrode width is preferably as large as possible within the range not exceeding the transparent electrode width in order to enhance the light shielding effect. .

  In order to reduce the area between the scanning main electrode 22 and the sustaining main electrode 24, the width of each main electrode may be reduced or the discharge gap may be reduced. However, when the main electrode width is narrowed, the electrode resistance formed by the synthesis of each main electrode and the bus electrode attached thereto increases, so that the main electrode width and the bus electrode width need to be more than a certain thickness. Further, changing the discharge gap is not preferable because it greatly affects the drive characteristics. In order to reduce the electrode resistance and improve the light-shielding property, the bus electrode width should be large, and considering the displacement, it is necessary to make it smaller than the main electrode width (for example, 40 μm). In the case where the bus electrode is formed by a thick film Ag layer by screen printing, for example, the main electrode width is 80 μm and the position shift is slightly different depending on the film thickness, the particle density of the Ag paste and the target electrode resistance value. In consideration of the design, the bus electrode width is preferably 40 μm or the like.

  On the other hand, for example, in a design in which the main electrode width is 50 μm and the bus electrode width is 10 μm in consideration of misalignment, the bus electrode is too thin and the electrode resistance increases, so that it operates normally even when a drive pulse is applied. There are things that do not. For this reason, it is appropriate to set the bus electrode width to at least half of the main electrode width as a guide for designing the main electrode width and the bus electrode width. In addition, the width of the extended electrode that greatly affects the light emission luminance due to the sustain discharge may be appropriately adjusted according to the target sustain light emission luminance. In this case, if the extended electrode width is increased, the sustained light emission luminance is increased, and if the extended electrode width is decreased, the sustained light emission luminance is decreased.

  As described above, in the first embodiment, the preliminary discharge region is completely limited to the region sandwiched between the scanning main electrode 22 and the sustaining main electrode 24, and the discharge light emission in the region is the same. Since the light is shielded by the bus electrodes 22a and 24a attached to the scanning main electrode 22 and the sustaining main electrode 24, most of the light emission due to the preliminary discharge is not emitted to the display surface side, and the black due to the light emission due to the preliminary discharge is not emitted. The brightness is greatly reduced and the contrast ratio is greatly improved.

  The first embodiment has a problem in that the contrast ratio is not always sufficiently improved because the portion of the discharge gap 29 which is the light emitting region by the preliminary discharge is not shielded from light. For this reason, in the following Example 2, this problem is improved.

FIG. 7 is a plan view showing the configuration of a unit cell of a PDP according to the second embodiment of the present invention. Elements common to those in FIG. 3 showing the first embodiment are denoted by common reference numerals. Has been. 8 is a cross-sectional view taken along line AA in FIG.
In the unit cell of the PDP in this example, a black dielectric layer 58 is provided on the upper side of the scanning main electrode 22 and the sustaining main electrode 24 as shown in FIG. The black dielectric layer 58 is formed so as to directly cover the region including the scanning main electrode 22, the sustaining main electrode 24, the bus electrodes 22a and 24a, and the discharge gap 29 in FIG. Further, as shown in FIG. 8, the black dielectric layer 58 is formed in the transparent dielectric layer 53. In this case, first, a transparent dielectric layer 53 is formed so as to cover all the electrodes, a black dielectric layer 58 is laminated thereon, and further transparent so as to cover all regions including the black dielectric layer 58. A dielectric layer 53 is formed. The black dielectric layer 58 blocks light emitted from the scanning main electrode 22 and the sustaining main electrode 24.

  In this PDP, since the portion of the discharge gap 29 is shielded by the black dielectric layer 58, almost all of the light emission by the preliminary discharge is shielded. Thereby, the black luminance due to the light emission luminance in the preliminary discharge becomes so small that it cannot be visually recognized, and the contrast ratio of the display screen is improved as compared with the first embodiment. Further, since most of the regions of the scanning main electrode 22 and the sustaining main electrode 24 are shielded from light by the black dielectric layer 58, the widths of the bus electrodes 22a and 24a are set to the scanning main electrode 22 and the sustaining main electrode 24 for shielding. There is no need to expand to the same width. For this reason, the widths of the bus electrodes 22a and 24a need only take into account the electrode resistance, so that the degree of freedom in design increases.

FIG. 9 is a plan view showing the structure of a unit cell of a PDP according to the third embodiment of the present invention. Elements common to those in FIG. 7 showing the second embodiment are denoted by common reference numerals. Has been. FIG. 10 is a cross-sectional view taken along line AA in FIG.
In the unit cell of the PDP in this example, a black dielectric layer 58A having a different formation region is provided instead of the black dielectric layer 58 in FIG. As shown in FIG. 10, the black dielectric layer 58A is formed almost only in the region above the discharge gap 29, and the scan main electrode 22 and the sustain main electrode 24 are not formed in the upper region.

  In this PDP, the portion of the discharge gap 29 is shielded by the black dielectric layer 58A, and the regions of the scanning main electrode 22 and the sustaining main electrode 24 are shielded by the bus electrodes 22a and 24a, as in the first embodiment. . For this reason, the contrast ratio of the display screen is improved, and the formation region of the black dielectric layer 58A is narrowed, so that the material for forming the black dielectric layer 58A is reduced.

  In the above embodiments, the number of extraction terminals of the scanning main electrode 22 and the scanning extension electrode 23 of the PDP 21 is twice that of the conventional scanning electrode. For example, in a PDP having 480 scanning rows in the vertical direction, in the conventional configuration, 480 scanning electrode terminals may be provided, but in the configuration of each of the above embodiments, 480 scanning main electrode terminals, In addition, a total of 960 electrode terminals, ie, 480 extended scanning electrode terminals, are required, resulting in a complicated configuration. Further, there is a problem in that the sustain discharge light emission is shielded by the bus electrodes 23a and 25a formed on the scan extension electrode 23 and the sustain extension electrode 25. For this reason, in the following Example 4, these problems are improved.

FIG. 11 is a diagram showing a configuration of a PDP according to a fourth embodiment of the present invention. Elements common to those in FIG. 2 showing the first embodiment are denoted by common reference numerals.
In the PDP 21A of this example, unit cells 27A are formed in the intersecting regions of the data electrodes 26a and 26b and the scanning main electrode 22, and cell groups are arranged in a matrix in the row direction H and the column direction V. . In the unit cells 27A adjacent in the vertical direction (column direction V), the sustain extension electrodes 25 or the scan extension electrodes 23 are arranged adjacent to each other.

FIG. 12 is a plan view showing the configuration of the unit cell 27A in FIG.
In the unit cell 27A, the sustain expansion electrode 25 of the unit cell 27A is electrically connected and integrated with a sustain expansion electrode of a unit cell (not shown) adjacent in the upward direction via a connecting portion 61. Further, the scan extension electrode 23 of the unit cell 27A is connected to and integrated with a scan extension electrode of a unit cell (not shown) adjacent in the downward direction via a connecting portion 62. The connecting portions 61 and 62 are formed on the partition wall 28 and pass through the central axis C. Further, a bus electrode 25a is formed at the center of the two integrated sustaining extension electrodes 25 (that is, the center of the connecting portion 61), and the center of the two integrated scanning extension electrodes 23 (that is, the center of the connecting extension 61). The bus electrode 23a is formed at the center of the connecting portion 62).

  In this PDP 21A, for example, when there are 480 scanning rows in the vertical direction, the number of scanning extended electrode terminals is reduced to 240, and the total number of terminals with the scanning main electrode terminals is reduced to 720 (480 + 240). Since the bus electrodes 23a and 25a are formed at the central portions of the connecting portions 62 and 61, respectively, the influence of the light emission from the sustain discharge light emission is suppressed, and the sustain discharge light emission efficiency is improved.

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 fourth embodiment, as shown in FIG. 13, instead of the connecting portion 61 in FIG. 12, connecting portions 63 and 64 formed on the partition wall 28 may be provided. Further, as shown in FIG. 14, a sustain expansion electrode 25 </ b> A may be provided instead of the sustain expansion electrode 25 in FIG. 12. The sustain expansion electrode 25A is integrated with a sustain expansion electrode of an adjacent unit cell (not shown) by expanding the sustain expansion electrode 25 upward. Further, instead of the scan extension electrode 23 in FIG. 12, a scan extension electrode 23A may be provided. The scan extension electrode 23A is integrated with a scan extension electrode of an adjacent unit cell (not shown) by expanding the scan extension electrode 23 downward.

  Further, as shown in FIG. 15, a connecting portion 61 </ b> B may be provided instead of the connecting portion 61 and the sustain expansion electrode 25 in FIG. 12. The connecting portion 61B has the function of a sustain expansion electrode by expanding the connecting portion 61 in the vertical direction. Further, a connecting portion 62B may be provided instead of the connecting portion 62 and the scan extension electrode 23 in FIG. The connecting portion 62B has the function of a scanning extension electrode by expanding the connecting portion 62 in the vertical direction. The configuration shown in FIG. 13, FIG. 14, or FIG.

  Further, in FIG. 5 showing the first embodiment, the sub-scanning pulse p is applied to the sustain main electrode 24 and the scan main electrode 22 is scanned in the scan period T2 as in the conventional drive waveform shown in FIG. A base pulse q may be applied. In FIG. 5, the reference potentials of the scan main electrode 22, the scan extension electrode 23, the sustain main electrode 24, the sustain extension electrode 25, and the data electrodes 26a and 26b are indicated by broken lines. Various settings may be made. For example, if the reference potentials of the scan main electrode 22, the scan extension electrode 23, the sustain main electrode 24, and the sustain extension electrode 25 are set to the same value, the scan main electrode driver 32, the scan extension electrode driver 33, the sustain main electrode driver 34, In addition, the number of power supplies supplied to the sustain expansion electrode driver 35 can be minimized, and the scale of the power supply circuit 45 is reduced.

  Further, if the reference potentials of the scanning main electrode 22 and the sustaining main electrode 24 are made lower than the reference potentials of the scanning extension electrode 23 and the sustaining extension electrode 25, various outputs output from the scanning main electrode driver 32 and the sustaining main electrode driver 34. Since the voltage level of the pulse can be set low, power consumption is reduced. Further, if the reference potentials of the scan extension electrode 23 and the sustain extension electrode 25 are set lower than the reference potentials of the scan main electrode 22 and the sustain main electrode 24, various outputs output from the scan extension electrode driver 33 and the sustain extension electrode driver 35. Since the voltage level of the pulse can be set low, power consumption is reduced.

  Further, the black dielectric layer 58 in FIG. 8 may be formed in contact with the protective layer 54. Further, although the number of subfields shown in FIG. 19 is set to four, it may be set to a number corresponding to the required number of gradations, such as eight subfields. When eight subfields are set, the time width of the sustain period of each subfield is set to a ratio of 1: 2: 4: 8: 16: 32: 64: 128, and there are 256 gradations (0 to 255). Is displayed.

  The present invention can be applied to all plasma display devices that are required to improve the contrast ratio of the display screen.

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 the figure which extracted PDP21 in FIG. FIG. 3 is a plan view of a unit cell 27 in FIG. 2. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a voltage waveform diagram of each part for demonstrating operation | movement of the plasma display apparatus of FIG. It is a figure explaining the result by which contrast ratio was improved. It is a top view which shows the structure of the unit cell of PDP which is 2nd Example of this invention. It is the sectional view on the AA line of FIG. It is a top view which shows the structure of the unit cell of PDP which is 3rd Example of this invention. FIG. 10 is a sectional view taken along line AA in FIG. 9. It is a figure which shows the structure of PDP which is the 4th Example of this invention. It is a top view which shows the structure of the unit cell 27A in FIG. It is a figure which shows the modification of a 4th Example. It is a figure which shows the modification of a 4th Example. It is a figure which shows the modification of a 4th Example. It is a top view which shows typically the electrode arrangement | positioning of PDP used for the conventional plasma display apparatus. It is a top view of the unit cell 5 in FIG. It is the sectional view on the AA line of the unit cell 5 of FIG. It is a figure explaining the principle of the gradation display method used for PDP of FIG. It is a figure which shows the drive waveform applied to each electrode in each subfield in FIG.

Explanation of symbols

21 Display panel (Plasma display panel)
22 Scanning main electrode 22a, 23a, 24a, 25a Bus electrode (light shielding means)
23, 23A Scanning extension electrode 24 Maintenance main electrode 25, 25A Maintenance extension electrode 26a, 26b Data electrode 27, 27A Unit cell 28 Partition 29 Discharge gap 31a, 31b Data driver (part of driving means)
32 Scanning main electrode driver (part of driving means)
33 Scanning extended electrode driver (part of driving means)
34 Maintenance main electrode driver (part of driving means)
35 Maintenance expansion electrode driver (part of driving means)
41 A / D (analog / digital) conversion circuit (part of driving means)
42 Pixel conversion circuit (part of driving means)
43 Subfield conversion circuit (part of driving means)
44 Controller (part of drive means)
45 Power supply circuit (part of drive means)
51 Front substrate (first substrate)
52 Back substrate (second substrate)
53 Transparent dielectric layer (part of plasma display panel)
54 Protective layer (part of plasma display panel)
55 White dielectric layer (part of plasma display panel)
56 Phosphor layer (part of plasma display panel)
57 Discharge space 58, 58A Black dielectric layer (light shielding means)
61, 61B, 62, 62B, 63, 64 Connection part da, db Preliminary discharge pulse e Preliminary erasing discharge pulse f Scan pulse g Display data pulse ha, hb Sustain pulse

Claims (10)

A plasma display panel;
A plasma display device comprising a 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 is:
A first substrate and a second substrate disposed opposite to each other;
A plurality of main electrode pairs comprising a scanning main electrode and a sustaining main electrode provided on a surface of the first substrate facing the second substrate and arranged in parallel with each other across a discharge gap;
A scan extension electrode provided on a surface of the first substrate facing the second substrate at a predetermined interval on the opposite side of the discharge gap with respect to the scan main electrode, and the sustain main electrode A plurality of pairs of extended electrodes made up of sustain extended electrodes provided at a predetermined interval on the opposite side of the discharge gap,
A plurality of data electrodes provided on the surface of the second substrate facing the first substrate in a form intersecting with the main electrode pairs and the extended electrode pairs;
A plurality of unit cells formed by being surrounded by a partition wall in each intersection region of the plurality of main electrode pairs and the plurality of extended electrode pairs and the plurality of data electrodes;
A discharge space formed by sealing a discharge gas between the first substrate and the second substrate, including the inside of each unit cell;
A light shielding means for shielding most of light emission in the scanning main electrode and the sustaining main electrode,
The driving means includes
For each subfield, a preliminary discharge pulse for performing preliminary discharge for all the unit cells is applied only to the scan main electrode and sustain main electrode, while applied to the scan extension electrode and sustain extension electrode. Without applying a scan pulse line-sequentially to each scan main electrode, and simultaneously generating a display discharge in synchronization with the scan pulse to each data electrode to generate an address discharge in the selected unit cell, A plasma display device, wherein all or most of sustain pulses are alternately applied to the scan extension electrode and the sustain extension electrode to generate a sustain discharge in each selected unit cell. The driving means includes
2. The plasma according to claim 1, wherein when the sustain pulse is applied to the scan extension electrode and the sustain extension electrode, the sustain pulse is simultaneously applied to the scan main electrode and the sustain main electrode. Display device. The scanning main electrode or the sustaining main electrode is
A transparent electrode and a metal bus electrode are laminated and configured.
The width of the bus electrode attached to the scanning main electrode or the sustaining main electrode is set to be smaller than the width of the corresponding transparent electrode and more than half of the width of the transparent electrode, and the bus electrode is shielded from the light. 3. The plasma display device according to claim 1, wherein the plasma display device comprises means. The scanning main electrode or the sustaining main electrode is
3. The plasma display device according to claim 1, wherein the plasma display device is formed of only metal bus electrodes, and the bus electrodes constitute the light shielding means.   5. The plasma display device according to claim 1, wherein a black dielectric layer that shields light emitted from the scanning main electrode and the sustaining main electrode is provided at least in a region including the discharge gap. .   The at least one of the two scanning extension electrodes belonging to the unit cell adjacent in the vertical direction or the two sustaining extension electrodes are electrically connected and integrated. The plasma display device according to 2, 3, 4 or 5.   7. A bus electrode is formed at the center of the two scanning extension electrodes that are electrically connected and integrated, or the two sustaining extension electrodes. Plasma display device. The two scanning extension electrodes that are electrically connected and integrated, or the two maintenance extension electrodes,
8. The plasma display device according to claim 7, wherein the plasma display device is electrically connected through a connecting portion passing through a center line of the unit cell. The two scanning extension electrodes that are electrically connected and integrated, or the two maintenance extension electrodes,
8. The plasma display device according to claim 7, wherein the plasma display device is electrically connected through a connecting portion formed on a partition wall surrounding the unit cell. A plasma display panel;
A driving method used for a plasma display device comprising: driving means for driving the plasma display panel by dividing one field of a display screen into a plurality of subfields weighted based on gradation levels. ,
The plasma display panel;
A first substrate and a second substrate disposed opposite to each other;
A plurality of main electrode pairs comprising a scanning main electrode and a sustaining main electrode provided on a surface of the first substrate facing the second substrate and arranged in parallel with each other across a discharge gap;
A scan extension electrode provided on a surface of the first substrate facing the second substrate at a predetermined interval on the opposite side of the discharge gap with respect to the scan main electrode, and the sustain main electrode A plurality of pairs of extended electrodes made up of sustain extended electrodes provided at a predetermined interval on the opposite side of the discharge gap,
A plurality of data electrodes provided on the surface of the second substrate facing the first substrate in a form intersecting with the main electrode pairs and the extended electrode pairs;
A plurality of unit cells formed by being surrounded by a partition wall in each intersection region of the plurality of main electrode pairs and the plurality of extended electrode pairs and the plurality of data electrodes;
A discharge space formed by sealing a discharge gas between the first substrate and the second substrate, including the inside of each unit cell;
A light shielding means for shielding most of the light emitted from the scanning main electrode and the sustaining main electrode;
For each subfield, a preliminary discharge pulse for performing preliminary discharge for all the unit cells is applied only to the scan main electrode and sustain main electrode, while applied to the scan extension electrode and sustain extension electrode. Without applying a scan pulse line-sequentially to each scan main electrode, and simultaneously generating a display discharge in synchronization with the scan pulse to each data electrode to generate an address discharge in the selected unit cell, A driving method, wherein all or most of sustain pulses are alternately applied to the scan extension electrode and the sustain extension electrode to generate a sustain discharge in each of the selected unit cells.

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