Patent Grant
6882327
1. Field of the Invention
The present invention relates to a plasma display panel and a drive method for the same.
2. Description of the Related Art
Generally, a plasma display panel (hereinafter, abbreviated to PDP) has many advantages whereby a thin and large screen display can be easily realized, the angle of view is wide, and the response speed is high. Therefore, recently, PDPs have been used as flat displays in the forms of wall-hung televisions, public bulletin boards and the like. PDPs are divided by operation methods into a direct current discharge type (DC type) to be operated in a direct current discharge condition where electrodes are exposed to a discharge space (discharge gas), and an alternating current discharge type (AC type) to be operated in an alternating current discharge condition where electrodes are coated with dielectrics and prevented from being directly exposed in a discharge gas.
In the DC type, discharge occurs during a period in which a voltage is applied, and in the AC type, discharge is continued by inverting the polarity of a voltage. Furthermore, the AC type is divided into two types, a type having two electrodes in one cell and a type having three electrodes in one cell.
Herein, the structure of the conventional 3-electrode AC type plasma display panel and a drive method therefor are explained.
The 3-electrode AC type plasma display panel comprises front substrate 20 and back substrate 21 which are opposed to each other, a plurality of X electrodes 22 and Y electrodes 23, and data electrodes 29 disposed between the substrates 20 and 21, display cells disposed in a matrix form at intersections between the X electrodes 22 and Y electrodes 23 and the data electrodes 29.
A glass plate or the like is used for the front substrate 20, and the X electrodes 22 and Y electrodes 23 are provided at predetermined intervals. Metal electrodes 32 are laminated on the X electrodes 22 and Y electrodes 23 to lower wiring resistances. On these electrodes, transparent dielectric layer 24 and protective layer 25 made from MgO or the like for protecting the transparent dielectric layer 24 from discharge are formed. Meanwhile, a glass plate is used for the back substrate 21, and data electrodes 29 are provided so as to be orthogonal to the X electrodes 22 and Y electrodes 23. Furthermore, on the data electrode 29, white dielectric layer 28 and fluorescent layer 27 are provided. Between the two glass substrates, partitions are formed in parallel to the paper surface at predetermined intervals. The partitions form discharge spaces and partition or define pixels. Within the discharge space 26, a mixed gas of He, Ne, Xe, and the like is sealed. Such a structure is mentioned in “Society for Information Display 98 Digest”, p. 279-281, May 1998.
Next, a method for driving the PDP is explained. The current mainstream provides an address display separation method (ADS method) in which scanning periods and sustaining periods are separated. Hereinafter, a drive method for this ADS method is explained.
First, the preliminary discharge period 2 is explained. A negative preliminary discharge pulse 6 is applied to the X electrode 22, and a positive preliminary discharge pulse 5 is applied to the Y electrode 23. Thereby, a difference in formation of wall charges at the final point of the previous SF due to the emission condition of the previous SF is reset and initialized, and at the same time, all pixels are forcibly discharged, and a priming effect for subsequent writing discharge at a low voltage is obtained. In
Next, the period enters the scanning period 3. In the scanning period 3, scanning pulses 7 are applied to the X1 through Xm of the X electrodes 22 in order. In accordance with the scanning pulses 7, data pulses 9 are applied to D1 through Dn of the data electrodes 29 in accordance with the display patterns. In a pixel to which the data pulse 9 has been applied, a high voltage is applied between the X electrode 22 and data electrode 29, so that writing discharge occurs, a great positive wall charge is formed at the X electrode 22 side, and a negative wall charge is formed at the data electrode 29 side. On the other hand, in a pixel to which the data pulse 9 has not been applied, the applied voltage is low, so that discharge does not occur, and the status of the wall charge does not change. Thus, depending on the existence of the data pulse 9, two statuses of wall charges can be created. The diagonal lines of the data pulses 9 in the Figure indicate that the existence of the data pulse 9 changes in accordance with display data.
When application of the scanning pulses 7 to all lines is finished, the period enters the sustaining period 4. Sustaining pulses 10 are alternately applied to all X electrodes 22 and all Y electrodes 23. The voltage values of the sustaining pulses 10 are set so as not to cause discharge by themselves. Therefore, in a pixel without occurrence of writing discharge, wall charge is little, so that discharge does not occur even when a sustaining pulse is applied. On the other hand, in a pixel in which writing discharge has been occurred, a great positive wall charge exists at the X electrode 22 side, this positive wall charge is superposed on the first positive sustaining pulse (referred to as a first sustaining pulse) applied to the X electrode 22 and, a voltage higher than the discharge starting voltage is applied to the discharge space, whereby sustaining discharge occurs. Due to this discharge, negative wall charges are accumulated at the X electrode 22 side, and positive wall charges are accumulated at the Y electrode 23 side. The next sustaining pulse (referred to as a second sustaining pulse) is applied to the Y electrode 23 side, and in response to superposition of the wall charge, sustaining discharge also occurs herein, and wall charges with a polarity opposite to that of the first sustaining pulse are accumulated at the X electrode 22 side and Y electrode 23 side. Thereafter, discharge still continuously occurs based on the same principle. That is, a potential difference caused by a wall charge generated due to the x-th sustaining discharge is superposed on the x+1-th sustaining pulse and the sustaining discharge is continued. A light emission amount is determined by the number of sustaining discharge continuance.
The whole of the abovementioned sustaining eliminating period 2, scanning period 3, and sustaining period 4 is referred to as a subfield. When gradation display is carried out, one field which is a period for displaying image information for one screen is comprised of a plurality of subfields. Gradation display can be achieved by changing the number of sustaining pulses of each subfield and turning each subfield on/off.
Thus, a display screen with m lines is driven in a progressive (non-interlace) manner by using m of X electrode drivers and one Y electrode driver.
However, in the abovementioned structure and drive method, non-discharge gap 38 which is the interval between the X electrode and the Y electrode in the next cell must be larger than the discharge gap 37, and this is not suitable for highly fine panels. Therefore, as generally known examples of a panel structure and a drive method suitable for high fineness, there are a plasma display panel drive method and a plasma display panel device described in Japanese Unexamined Patent Publication No. 160525 of 1997.
FIG. 5 and
Data pulses 9 are applied in response to the scanning pulses 7 to D1 through Dn of the data electrodes 29 in accordance with display patterns. The method for applying the data pulses 9 at this time is shown in FIG. 7. In
First, the case of an odd-numbered field is explained. Among the first, third, and fifth pixels, only the first pixel is a lighting pixel. Therefore, only when a scanning pulse 13 is applied to X1 which is the X electrode 22 of the first pixel, a data pulse 9 is applied. When application of scanning pulses 8 to all lines is finished, the period enters the sustaining period 4. In the odd-numbered field, odd-numbered X electrodes and even-numbered Y electrodes have the same phase, and even-numbered X electrodes and odd-numbered Y electrodes have the same phase. Thereby, in a pixel in which wall charge has been formed in the scanning period, sustaining discharge occurs between the odd-numbered X electrodes and even-numbered Y electrodes and between the even-numbered X electrodes and odd-numbered Y electrodes. In the conventional example of
Next, the case of an even-numbered field is explained. The second and fourth pixels are lighting pixels, so that data pulses 9 are applied both when a scanning pulse 13 is applied to X1 which is the X electrode 22 of the second pixel and when a scanning pulse 13 is applied to X2 which is the X electrode 22 of the fourth pixel. When application of scanning pulses 13 to all lines is finished, the period enters sustaining period 4. In an even-numbered field, odd-numbered X electrodes and odd-numbered Y electrodes have the same phase, and even-numbered X electrodes and even-numbered Y electrodes have the same phase. Thereby, in a pixel in which a wall charge has been formed in the scanning period, sustaining discharge occurs between the odd-numbered X electrodes and odd-numbered Y electrodes and between the even-numbered X electrodes and even-numbered Y electrodes. Also herein, in the second pixel, sustaining discharge does not occur during the first sustaining, however, as the odd-numbered field, sustaining discharge starts from the second sustaining and is continued thereafter.
As mentioned above, if the two odd-numbered and even-numbered fields are joined together, display can be carried out between all X electrodes and Y electrodes, so that a highly fine display can be realized.
Thus, by using m of X electrode drivers and two of Y electrode drivers, a display screen with 2 m lines which is two times the lines of the conventional example can be displayed. However, in this case, interlace drive is employed.
However, the number of scanning lines increases for realizing a highly fine panel. Accordingly, the number of scanning drivers also increases, and production costs increase. On the other hand, as shown in the prior art, a method may be used in which interlace drive is employed and the number of scanning drivers can be reduced. However, image quality deteriorates due to interlace drive.
The object of the invention is to provide a plasma display panel and a drive method therefor wherein the number of scanning drivers or the total number of X electrode drivers and Y electrode drivers can be reduced by employing progressive (non-interlace) drive.
A plasma display panel (PDP) of the invention is an AC type plasma display panel (PDP) wherein, a plurality of X electrodes and a plurality of Y electrodes are alternately arranged in parallel to each other on one of two insulating substrates opposed to each other, and a plurality of data electrodes are arranged on the other insulating substrate so as to be orthogonal to the X electrodes and Y electrodes, a gap between an X electrode and Y electrode adjacent to the X electrode is formed as a discharge gap, and a gap between the X electrode and another Y electrode adjacent to the X electrode is formed as a non-discharge gap, pixels arranged in a matrix form are disposed at intersections between the discharge gaps and data electrodes, and every several X electrodes and every several Y electrodes are made to share a driver each. To drive the abovementioned PDP, when writing to each pixel to form wall charges, by writing the same amount of wall charge into the X electrode and Y electrode in one pixel, lighting and non-lighting may be controlled depending on the wall charge amounts. Furthermore, to drive the PDP, when writing to form wall charges in each pixel based on display data, wall charges may be written by making the potentials of the X electrode and Y electrode in one pixel equal to each other, and lighting and non-lighting may be controlled based on the wall charge amount. Furthermore, to drive the PDP, when writing to form wall charges in each pixel based on display data, the voltages of the wall charges formed in the X electrode and Y electrode within one pixel mentioned above may be set to a level at which surface discharge does not occur between the X electrodes and Y electrodes even if the sustaining pulse voltages are joined together.
The PDP according to the invention may be an AC type plasma display panel (PDP) constructed so that a plurality of X electrodes and a plurality of Y electrodes are alternately arranged in parallel to each other on one of two insulating substrates opposed to each other, a plurality of data electrodes are arranged on the other insulating substrate so as to be orthogonal to the X electrodes and Y electrodes, all gaps between the X electrodes and Y electrodes are formed as discharge gaps, and pixels arranged in a matrix form are formed at intersections between the discharge gaps and data electrodes, means for dividing surface discharge between the X electrode and Y electrode at the boundaries between the electrodes and adjacent pixels in the data electrode direction are provided on the X electrodes and Y electrodes, and either every several X electrodes or Y electrodes are made to share a driver. To drive this PDP, when writing and forming wall charges into each pixel based on display data, the same amount of wall charge is written into the X electrode and Y electrode within one pixel, and lighting and non-lighting of the pixel may be controlled depending on the wall charge amounts. Furthermore, to drive this PDP, when writing and forming wall charges in each pixel based on display data, wall charges may be written by setting the potentials of the X electrode and Y electrode within one pixel to be equal to each other, and lighting and non-lighting of the pixel may be controlled depending on the wall charge amounts. Furthermore, to drive this PDP, when writing and forming wall charges in each pixel based on display data, the voltages of wall charges to be formed in the X electrode and Y electrode within one pixel may be set to be a voltage at which surface discharge does not occur between the X electrode and Y electrode even if the sustaining pulse voltage is added to them.
The plasma display panel of the invention is an AC type plasma display in which a plurality of X electrodes and a plurality of Y electrodes are alternately arranged in parallel to each other on one of two insulating substrates opposed to each other, a plurality of data electrodes are arranged on the other insulating substrate so as to be orthogonal to the X electrodes and Y electrodes, all gaps between the X electrodes and Y electrodes are formed as discharge gaps, pixels arranged in a matrix form are disposed at intersections between the discharge gaps and data electrodes, means for dividing surface discharge between the X electrodes and Y electrodes at the boundaries between the electrodes and adjacent pixels in the data electrode direction are provided on the X electrodes and Y electrodes, and either every several X electrodes or Y electrodes are made to share a driver. Furthermore, in this panel, the means for dividing surface discharge between X electrodes and Y electrodes at boundaries between the electrodes and adjacent pixels in the data electrode direction, which are provided on X electrodes and Y electrodes, are cell partitions which are provided on the insulating substrate with the X electrodes and Y electrodes so as to be along the X electrodes and Y electrodes.
Hereinafter, embodiments of the invention are explained with reference to the drawings.
On the other hand, data electrodes 29 are formed from Ag or the like so as to be approximately 2 through 4 μm in thickness on the lower insulating substrate 21. Above them, white dielectric layers 28 are provided. The white dielectric layers 28 are formed to be approximately 5 through 40 μm in thickness by using white glass paste obtained by mixing PbO—B2O3—SiO2-based low melting point glass paste with a relative dielectric constant of approximately 10 through 25 and TiO2 at a ratio of 10:1, and then baked at 500 through 600° C. Above them, cell partitions 34 are formed to be approximately 40 through 50 μm in height by printing white glass paste and baking it at 500 through 600° C. Next, vertical line partitions 36 at the lower insulating substrate 21 side are formed by applying the paste and then applying sandblasting. At this time, the height of the vertical line partitions 36 is increased to be approximately 20 μm higher than the height of the cell partitions 34 so that gaps as exhaust paths are formed between the cell partitions 33 and 34 when the two insulating substrates 20 and 21 are adhered together. Finally, fluorescent materials 9 are applied to be approximately 10 through 15 μm in thickness. At this time, if the kinds of fluorescent materials are distinguished by RGB (red, green, blue) for each cell, full-color display becomes possible. (Y,Gd)BO3:Eu is used for the R (red) fluorescent material, Zn2SiO4:Mn is used for the G (green) fluorescent material, and BaMgAl10O17:Eu is used for the B (blue) fluorescent material.
The two insulating substrates are adhered together and baked at 350 through 500° C., and then gases inside the cells are exhausted, and a mixed gas of He, Ne, and Xe is sealed within the cells by 200 through 600 torr as a discharge gas and sealed up, whereby the panel is completed.
Next, a drive method of a first embodiment of the invention is explained with reference to FIG. 11. In the preliminary discharge period 2, positive preliminary discharge pulses are applied to the X electrodes 22, and negative preliminary discharge pulses are applied to the Y electrodes 23. The voltage of the positive preliminary discharge pulse 5 is set to 160V, and the voltage of the negative preliminary discharge pulse 6 is set to −160V. The pulse width is set to 4 through 10 μsec.
Next, the period enters the scanning period 3. The voltages applied to the X electrodes are dropped to 0V in order. The “ts” (s is an integer) in
Next, the operation at this time is explained with reference to the drawings showing the wall charge formation conditions of
In the preliminary discharge period 2, surface discharge occurs between the X electrode 22 and Y electrode 23, a negative wall charge is formed on the X electrode 22, and a positive wall charge is formed on the Y electrode 23. The wall charge formation condition at this time is as shown in FIG. 22A. In
When the preliminary discharge period 2 is ended, the period enters the scanning period 3. The potential of the X1 electrode drops to 0V at the timing t1 in the scanning period 3. At the same timing, the odd-numbered line Y electrodes also drop to 0V. Therefore, due to the negative wall charge on the X1 electrode and the positive wall charge on the Y1 electrode, surface discharge occurs between the X1 electrode and Y1 electrode. At this time, the potentials of odd-numbered line Y electrodes other than the Y1 electrode also change, however, the potentials of the X electrodes adjacent to them do not change, so that surface discharge does not occur. That is, surface discharge occurs only at a portion at which potentials of both X electrode and Y electrode have dropped to 0V, surface discharge has not occurred yet in the scanning period 3, and wall charges that have been formed in the preliminary discharge period 2 still remain. At this timing t1, data pulses 9 corresponding to image signals are applied. In the present embodiment, negative data pulses are applied in the case of lighting cells. At the timing t1, the X1 electrode and Y1 electrode have the same potential, so that the same amount of wall charge is formed on them. At this time, cell partitions 33 are formed between adjacent cells at the centers of the X electrodes 22 and Y electrodes 23, so that the formation of wall charges is limited to a range sandwiched by the cell partition 33 on the X1 electrode and the cell partition 33 on the Y1 electrode, and wall charges on the X1 electrode and Y1 electrode at the opposite side of the cell partitions 33 do not change. If data pulses 9 are applied at this timing, positive wall charges are formed on the data electrodes 29, and negative wall charges are formed on the X1 electrode and Y1 electrode. On the other hand, if data pulses 9 are not applied, all potentials of the X1 electrode, Y1 electrode, and data electrodes 29 drop to 0V, so that wall charges disappear. The wall charge formation condition at this time is shown in FIG. 22B. In FIG. 22B and Figures after
Then, the period enters the sustaining period 4. In the sustaining period 4, sustaining pulses 10 with negative polarity are alternately applied to the X electrodes 22 and Y electrodes 23. In this embodiment, the sustaining pulses 10 are applied to the Y electrodes 23 first, however, the sustaining pulses may be applied to whichever first. The voltage of this sustaining pulse 10 is set so as not to cause surface discharge by itself (−160V in this embodiment). At the end of the scanning period 3, the amounts of wall charges formed on the X electrodes and Y electrodes in both lighting and non-lighting cells are the same. Therefore, even if the wall voltage is superposed on the sustaining pulses 10, the potential difference between the surface electrodes is almost 160V, which does not reach a voltage at which discharge is started. However, in a lighting cell, since negative wall charges are formed on the Y electrodes and positive wall charges are formed on the data electrodes, opposed discharge occurs between the Y electrodes and data electrodes. Due to this opposed discharge, as shown in
Thus, a 2m-line display screen can be progressively displayed by m of X electrode drivers and two of Y electrode drivers.
The second embodiment of the invention is explained with reference to both of the drive waveforms of FIG. 12 and the drawings showing the wall charge formation conditions of
In the first embodiment of the invention, for all X electrodes, writing by means of surface discharge between adjacent odd-numbered line Y electrodes and X electrodes precedes, and thereafter, writing by means of surface discharge between even-numbered line Y electrodes and X electrodes is carried out. On the other hand, in this embodiment, with respect to odd-numbered line X electrodes, writing is carried out to odd-numbered line Y electrodes and even-numbered line Y electrodes in this order, and with respect to even-numbered line X electrodes, writing is carried out to even-numbered line Y electrodes and odd-numbered Y electrodes in this order. Explanation is given according to time scale. At the timing t1, the potential of the X1 electrode drops to 0V, and at the same timing, the odd-numbered line Y electrodes also drop to 0V, so that due to the negative wall charge on the X1 electrode and the positive wall charge on the Y1 electrode, surface discharge occurs between the X1 electrode and Y1 electrode, and writing is carried out. At this time, odd-numbered line Y electrodes other than the Y1 electrode also change their potentials, however, since the potentials of the adjacent X electrodes do not change, surface discharge does not occur. Next, at the timing t2, the even-numbered line Y electrodes drop to 0V, so that surface discharge occurs between the X1 electrode and Y2 electrode, and between these electrodes, wall charges for writing are formed. Therefore, with respect to the X1 (odd-numbered line) electrode, writing is carried out between the electrode and the Y1 (odd-numbered line) electrode first, and then, writing is carried out between the electrode and the Y2 (even-numbered line) electrode. At the next timing t3, the potential of the X2 electrode drops to 0V. At this time, the odd-numbered line Y electrodes change their potentials from 0V to −160V, however, at the point at which the potential of the X2 electrode becomes 0V, the potentials of the odd-numbered line Y electrodes must be −160V. Therefore, it is desirable that the phases of Y2k−1 pulses slightly precede. Between the X2 and the Y electrodes adjacent to the X2, surface discharge occurs between the X2 and the Y2 electrodes since the Y2 electrode is at 0V, however, surface discharge does not occur between the X2 and Y3 electrodes since the Y3 electrode is at −160V. Subsequently, at the timing t4, since the odd-numbered line Y electrodes reach 0V, surface discharge for writing occurs between the X2 and Y3 electrodes. Thus, with respect to the X2 (even-number line) electrode, writing is carried out between the X2 and Y2 (even-numbered line) electrodes first, and then writing is carried out between the X2 and Y3 (odd-numbered line) electrodes. After the timing t5, t1 through t5 are repeated for the Y electrodes, the potential of the X electrodes successively drop to 0V, and writing discharge occurs from the upper side to the lower side in order. Thus, writing is carried out to all lines. Details of the sustaining period 4 are the same as in the first embodiment of the invention.
Thus, as in the first embodiment of the invention, a 2m-line display screen can be progressively displayed by m of X electrode drivers and two of Y electrode drivers.
The third embodiment of the invention is explained with reference to both drive waveforms of FIG. 13 and drawings showing wall charge formation conditions of
The cell structure and panel electrode arrangement are the same as in the first embodiment of the invention. The drive waveforms of the embodiment are the same as in the first embodiment of the invention except for the waveforms in the scanning period 3 of the odd-numbered line Y electrodes. In the preliminary discharge period 2, as in the first embodiment of the invention, wall charge arrangement as shown in
The order for causing surface discharge for writing is the same as in the first embodiment. That is, in both first and third embodiments of the invention, for all X electrodes, writing by means of surface discharge between the adjacent odd-numbered line Y electrodes and X electrodes precedes, and next, writing by means of surface discharge between the even-numbered line Y electrodes and X electrodes is carried out. The timings t1 and t2 are the same as in the second embodiment of the invention, and at the timing t1, surface discharge for writing occurs between the X1 electrode and Y1 electrode, and at the timing t2, surface discharge for writing occurs between the X1 electrode and Y2 electrode. At this timing t2, surface discharge has already occurred between the X1 electrode and Y1 electrode, the same wall charge amount has been formed, so that further discharge does not occur. Therefore, the potential of the Y1, that is, the odd-numbered line Y electrodes may be either 0V or −160V between them. Therefore, in this embodiment, the potential of the odd-numbered line Y electrodes at the timing t2 is left to be at 0V. The same can also be said for the timing ts (s: even numbers) after t2, so that the potentials of the odd-numbered line Y electrodes in the scanning period 3 are fixed to 0V.
Thus, writing is carried out to all lines in the same order as in the first embodiment of the invention. Details of the sustaining period 4 are the same as in the first embodiment of the invention.
Thus, as in the first embodiment of the invention, a 2m-line display screen can be progressively displayed by m of X electrode drivers and two of Y electrode drivers.
The fourth embodiment of the invention is explained with reference to all of the drive waveforms of
The cell structure is the same as in the first embodiment of the invention. As for arrangement of electrodes, as in the first embodiment of the invention, X electrodes 22 and Y electrodes 23 are alternately disposed at equal intervals. In this embodiment, the screen is divided into two, that is, an upper screen from the Y1 to Xm electrodes, and a lower screen from the Ym+1 to Y2m+1 electrodes, and these screens are driven, respectively, in the same manner as in the first embodiment of the invention. That is, as for the respective upper and lower screens, drive waveforms that are all independent are applied to the X electrodes 22, and drive waveforms which are different between the odd-numbered line Y electrodes and even-numbered line Y electrodes are applied to the Y electrodes 23. The X electrodes on the same-numbered lines of the upper and lower screens are made to share and are driven by the same X electrode driver. That is, as shown in
Next, the operation is explained. The preliminary discharge period 2 and sustaining period 4 are the same as in the first embodiment of the invention. In the preliminary discharge period 2, wall charges as shown in
Thus, a 4m-line screen can be progressively displayed by m of X electrode drivers and 4 of Y electrode drivers. Although the screen is divided into two upper and lower screens, the screen may be divided into more screens. If the screen is divided into r screens, 2r of Y electrode drivers become necessary. Therefore, a 2mr-line screen can be displayed by m of X electrode drivers and 2r of Y electrode drivers. For example, on the assumption that the numbers of X electrode drivers and Y electrode drivers are set to 32, respectively, m=32 and r=16, so that a 1024-line screen can be displayed. Thus, the number of display lines can be determined by multiplying the number of X electrode drivers by the number of Y electrode drivers. Therefore, to minimize the total number of X electrode drivers and Y electrode drivers, the number of X electrode drivers and the number of Y electrode drivers are made equal to each other.
The fifth embodiment of the invention is explained with reference to both of the drive waveforms of FIG. 5 and the panel plan view of FIG. 17. The cell structure, electrode arrangement, and driver connection are the same as in the fourth embodiment of the invention. The drive waveforms other than the drive waveforms of the Y electrode drivers in the scanning period 3 are the same as in the fourth embodiment of the invention. After surface discharge for writing has occurred, surface discharge occurs at neither 0V nor −160V of the potentials of the Y electrodes. Therefore, in the fourth embodiment of the invention, the potentials of the Y electrodes are restored to −160V after Δt after the occurrence of surface discharge for writing. On the other hand, in this embodiment, after 2Δt, the potentials are restored to −160V. Surface discharge occurs in neither of these cases, so that formation of wall charge is the same as in the fourth embodiment of the invention.
Thus, a 2m+1-line display screen can be progressively displayed by m of X electrode drivers and 4 of Y electrode drivers. Also in this embodiment, the number of divided screens can be increased as in the fourth embodiment of the invention.
The sixth embodiment of the invention is explained with reference to the drive waves of FIG. 16. The cell structure, panel electrode arrangement, and drive waves to be applied to the X electrodes and Y electrodes are the same as in the first embodiment of the invention. Therefore, the writing order is the same as in the first embodiment. In the scanning period 3, the voltage of data pulses 9 to be applied to the data electrodes is changed in three stages corresponding to display signals. In this embodiment, the voltage is changed to 0V, −40V, and −80V. In the middle of the sustaining period 4, a sustaining discharge starting control pulse 12 is applied.
Next, the operation is explained while additionally referring to
In the present embodiment, the data pulse voltage is changed in three stages, however, by increasing the number of stages, more gradations can be displayed by one scanning, and the number of subfields can be further reduced. If the number of subfields is reduced, the number of scanning periods 3 in one field can be reduced, and accordingly, the sustaining period 4 can be lengthened. At this time, as for the sustaining discharge starting control pulse 12, pulses with different voltages are increased in accordance with the number of data pulse voltage stages. Herein, the sustaining discharge starting control pulses are applied in the sustaining period 4 in order from pulses with smaller potential differences from that of the sustaining pulse 10. This is in order for the data pulse voltages to accord with the sustaining discharge starting timings at 1:1.
As drive waveforms of the X electrodes and Y electrodes, the drive waveforms of the first embodiment of the invention are employed in this embodiment, however, the same drive is also possible even when other drive waveforms of any of the second through fifth embodiments are employed.
The seventh embodiment of the invention is explained with reference to both of the drive waveforms of FIG. 11 and the panel plan view of FIG. 18. The cell structure is the same as in the conventional example of FIG. 2. The panel electrodes are arranged so that the discharge gaps 37 and non-discharge gaps 38 alternately exist as in the conventional example of FIG. 1. Every two X electrodes are made to share a driver. The drive waveforms are the same as in the first embodiment of the invention. First, in the preliminary discharge period 2, surface discharge occurs between all discharge gaps 37, and negative wall charges and positive wall charges are formed on the X electrodes 22 and Y electrodes 23, respectively. In the case of the present embodiment, no cell partitions 33 or 34 exist on the X electrodes 22 and Y electrodes 23. Therefore, when surface discharge for writing occurs, wall charges are formed on the entire surfaces of the electrodes. The method for writing is the same as in the first embodiment of the invention, surface discharge for writing is caused between the X electrodes 22 and Y electrodes 23, and in exact timing with this, the potentials of the data electrodes 29 are changed to change the wall charge accumulation amounts, whereby writing to lighting and non-lighting cells is changed. The writing order is also the same as in the first embodiment of the invention, that is, writing is carried out for the cell between the X1 and Y1 electrodes at the timing t1, the cell between the X1 and Y2 electrodes at the timing t2, and the cell between the X2 and Y3 electrodes at the timing t3. After writing is successively carried out, the period enters the sustaining period 4. The operation herein is also the same as in the first embodiment of the invention, and in a lighting cell, opposed discharge occurs first, and then surface sustaining discharge is continued. In this embodiment, the drive waveforms of the first embodiment are used, however, the drive waveforms of the second through sixth embodiments may be used.
Thus, a 2m-line display screen can be progressively displayed by m of X electrode drivers and 2 of Y electrode drivers.
The eighth embodiment of the invention is explained with reference to both of the drive waveforms of FIG. 14 and the panel plan view of FIG. 19. The cell structure is the same as in the conventional example of FIG. 2. As for the panel electrode arrangement, discharge gaps 37 and non-discharge gaps 38 alternately exist as in the conventional example of FIG. 1. In this embodiment, every four X electrodes 22 are driven by the same driver P, and a total of m of P drivers are used for driving. On the other hand, as for the Y electrodes 23, Y4k−3, Y4k−2, Y4k−1, and Y4k (k is an integer) are driven by four Q drivers of Q1, Q2, Q3, and Q4. As for the operation, writing is carried out in the same order as in the fourth embodiment of the invention. In this embodiment, the drive waveforms of the fourth embodiment of the invention are used, however, the drive waveforms of the fifth embodiment may be used.
Thus, a 4m-line display screen can be progressively displayed by m of X electrode drivers and 4 of Y electrode drivers. In this embodiment, every four X electrodes 22 are driven by the same driver P, however, the number of electrodes to be driven by the same driver may be increased. When every r of X electrodes 22 are driven by the same driver P, the total number of Y electrode drivers to be required is r. Therefore, a mr-line display screen can be displayed by m of X electrode drivers and r of Y electrode drivers. For example, when the numbers of X electrode drivers and Y electrode drivers are 32, respectively, m=32 and r=32, a 1024-line screen can be displayed. Thus, the number resulted by multiplying the number of X electrode drivers by the number of Y electrode drivers is the number of lines to be displayed. Therefore, to minimize the total number of X electrode drivers and Y electrode drivers, the number of X electrode drivers and the number of Y electrode drivers may be set to be equal to each other.
The ninth embodiment of the invention is explained with reference to both of the cell plan view of FIG. 9 and the cell sectional view of FIG. 20. The area surrounded by the dashed line in
The drive waveforms of the first embodiment of the invention are used in this embodiment, however, the drive waveforms and panel electrode arrangement of the second through sixth embodiments may be employed.
The tenth embodiment of the invention is explained with reference to the cell plan view of FIG. 21 and the cell sectional view of FIG. 10. In
In this embodiment, the drive waveforms of the first embodiment of the invention are used, however, the drive waveforms and panel electrode arrangement of the second through sixth embodiments may be used.
According to the invention described above, although only a m-line screen can be conventionally displayed by using a total of m+1 drivers including m of X electrode drivers and one Y electrode driver, display of a 2m-line screen becomes possible by using m of X electrode drivers and two of Y electrode drivers. As a monitor or TV display, m may be 480 or more, so that the same number of drivers can realize twice the display capacity. Furthermore, a plurality of X electrodes share one driver, the number of drivers can be further reduced, and 1024 lines can be displayed by using thirty-two of X electrode drivers and Y drivers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2000-388882 | Dec 2000 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6097358 | Hirakawa et al. | Aug 2000 | A |
| 6118416 | Nakamura et al. | Sep 2000 | A |
| 6373452 | Ishii et al. | Apr 2002 | B1 |
| Number | Date | Country |
|---|---|---|
| 0 762 373 | Mar 1997 | EP |
| 0 938 072 | Aug 1999 | EP |
| 05-002993 | Jan 1993 | JP |
| 6-44907 | Feb 1994 | JP |
| 09-160525 | Jun 1997 | JP |
| 9-244573 | Sep 1997 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20020070908 A1 | Jun 2002 | US |
