1. Field of the Invention
The present invention generally relates to plasma-display apparatuses, circuits for driving such apparatuses, and methods of driving such apparatuses, and particularly relates to a sub-frame-method-based plasma display apparatus, a circuit for driving such apparatus, and a method of driving such apparatus.
2. Description of the Related Art
Flat display apparatuses using flat display panels have been put to practical use in wide areas of application from small displays to large displays, and are replacing the conventional cathode-ray tubes. In the field of large-size displays, the plasma display panel (PDP) is regarded as superior due to its advantageous characteristics derived from the principle of operation and configuration, and are commercialized as mainstream products.
In order to facilitate further promulgation of the products, cost reduction of the apparatuses, improvements in the display characteristics, and further improvements in functionalities are desired. Moreover, there is an increasing demand for the reduction of various impacts on the environment such as EMI. In order to make further market progress into ordinary households, the further reduction of environmental impacts is necessary.
The three-electrode-type flat-plane-discharge AC-PDP panel includes two glass substrates, i.e., a front glass substrate 15 and a rear glass substrate 11. On the front glass substrate 15, common sustain electrodes (X electrodes) and scan electrodes (Y electrodes), each of which is comprised of a sustain-purpose BUS electrode 17 and transparent electrode 16, are formed. The X electrodes and the Y electrodes alternate with each other. A dielectric layer 18 is formed on the X electrodes and Y electrodes, and a protective layer 19 made of MgO or the like is formed on top of the dielectric layer 18.
The BUS electrode 17 has high conductivity, and serves as reinforcement for the conductivity of the transparent electrode 16. The protective layer 19 is made of low-melting-point glass, and serves to maintain discharge based on wall charge.
Address electrodes 12 are formed on the rear glass substrate 11 in such a manner as to extend perpendicularly to the X electrodes and Y electrodes. A dielectric layer 13 is formed on the address electrodes 12. On the dielectric layer 13, partition walls 14 are formed at positions corresponding to the gaps between the address electrodes 12.
Between the partition walls 14, fluorescent layers R, G, and B are formed to cover the dielectric layer 13 and the side walls of the partition walls. The fluorescent layers R, G, and B correspond to red, green, and blue, respectively. When the PDP is driven, electric discharge between the X electrodes and the Y electrodes generates ultraviolet light, which excites the fluorescent layers R, G, and B to emit light, thereby providing display presentation.
The gap between the front panel having the X electrodes and Y electrodes and the rear panel having the address electrodes 12 is filled with discharge gas such as a mixture of neon and xenon. Space at the position where an X electrode and Y electrode intersect with an address electrode constitutes a single discharge cell (pixel).
The control circuit 115 receives a clock signal CLK, display data D, a vertical synchronizing signal VSYNC, a horizontal synchronizing signal HSYNC, etc., from an external source, and generates control signals for controlling the panel operation based on the received signals and data. To be specific, the display data control circuit 116 receives the display data D for storage in the frame memory 119, and generates an address control signal responsive to the display data D stored in the frame memory 119 in synchronization with the clock signal CLK. The address control signal is supplied to the address driver circuit 111. The scan driver control circuit 117 generates a scan driver control signal for controlling the scan driver circuit 112 in synchronization with the vertical synchronizing signal VSYNC and the horizontal synchronizing signal HSYNC. The common driver control circuit 118 drives the Y common driver circuit 113 and the X common driver circuit 114 in synchronization with the vertical synchronizing signal VSYNC and the horizontal synchronizing signal HSYNC.
The address driver circuit 111 operates in response to the address control signal supplied from the display data control circuit 116, and applies address voltage pulses responsive to the display data to address electrodes A1 through Am. The scan driver circuit 112 operates in response to the scan driver control signal supplied from the scan driver control circuit 117, and drives scan electrodes (Y electrodes) Y1 through Yn independently of each other. While the scan driver circuit 112 successively drives the scan electrodes (Y electrodes) Y1 through Yn, the address driver circuit 111 applies address voltage pulses to the address electrodes A1 through Am, thereby selecting cells to emit light so as to control display/non-display (selected-state/unselected-state) of each cell 103.
The Y common driver circuit 113 applies sustain voltage pulses to the Y electrodes Y1 through Yn, and the X common driver circuit 114 applies sustain voltage pulses to the X electrodes X1 through Xn. The application of these sustain voltage pulses generates sustain discharge between an X electrode and a Y electrode at the cells selected as display cells. The address electrodes A1 through Am, X electrodes X1 through Xn, and Y electrodes Y1 through Yn are disposed between a front glass substrate 101 (corresponding to 15 in
In the reset period, voltage waveforms as shown in
In the address period, scan voltage pulses at the −Vy level are successively applied to the Y electrodes Y1 through Yn serving as scan electrodes, thereby driving the Y electrodes Y1 through Yn one by one. In synchronization with the application of the scan voltage pulses to the Y electrodes, address voltage pulses at the Va level are applied to the address electrodes (A1 through Am). This serves to select display cells on each scan line.
In the sustain period, sustain pulses (sustain voltage pulses) at the common Vs level (Vsy, Vsx) are alternately supplied to all the scan electrodes Y1 through Yn and the X common electrodes X1 through Xn With this arrangement, the pixels selected in the address period are cause to emit light. The continuous application of sustain pulses then achieves a display at predetermined luminance levels.
This basic operation of applying a series of drive waveforms may be combined with other basic operations to control the number of light emissions, thereby making it possible to represent gray tones.
There are many ways to assign the numbers of sustain pulses to the 10 sub-frames. In general, the numbers of sustain pulses in the 10 sub-frames are set to 20=1, 21=2, 22=4, . . . , and 29=512, respectively. Sub-frames forming a desired combination of sub-frames selected from these 10 sub-frames are caused to emit light, thereby making it possible to represent 1024 gray scales at the maximum.
The grayscale displaying method based on the conventional sub-frame method as described above is advantageous as it is relatively easy to control because display control is performed by using drive periods including the reset period, address period, and sustain period that are clearly separated in terms of their functions. In order to provide a sufficient time for each of the reset period, the address period, and the sustain period, however, the length of each sub-frame becomes undesirably long.
One completed set of sub-frames is referred to as a frame. Frames need to be displayed at 60 Hz or more in order to prevent flicker from appearing on screen, which means that each frame needs to be shorter than 16.7 ms. Due to such time restriction, an increase in the length of sub-frames results in a decreased number of sub-frames in one frame, thereby giving rise to a problem in that a sufficient number of gray scales are not provided.
Conversely, if an attempt is made to provide a sufficient number of sub-frames for the purpose of securing a sufficient number of gray scales, the time length that can be allocated to the driving of each of the reset period, address period, and sustain period becomes insufficient. As a result, a problem arises in that operation margin and drive stability degrade, creating a situation in which erroneous display may easily occur.
Further, since the plurality of drive periods are clearly separate from each other, and are used for respective, different drive operations as described above, the amount of required drive currents differs significantly from drive period to drive period. To be specific, the amount of electric current required for the sustain period is significantly larger than the amount of electric currents required in the other periods, giving rise to a problem in that there is large fluctuation in the consumed currents.
If the fluctuating component of the power-supply current (ripple current) is large, there is a need to provide a control circuit such as a stabilizer circuit that has a sufficient capacity to cope with the maximum value (peak current) of the fluctuating component, and, also, there is a need to provide circuit elements for interconnects having sufficient capacity. As a result, the apparatus becomes complex and expensive, which is disadvantageous from the cost point of view. Further, an increase in the peak current component means an increase in the radiation of noise signals from the drive circuits, thereby increasing the probability of circuit control suffering malfunction. There is another problem in that impact on the surrounding environment may become large due to the radiation of electromagnetic energy.
[Patent Document 1] Japanese Patent Application Publication No. 11-352925
Accordingly, there is a need for a sub-frame-method-based plasma display apparatus, a drive circuit, and a drive method that can provide a sufficient address drive period and sufficient sustain drive period while improving the performance of grayscale display. Further, there is a need for a sub-frame-method-based plasma display apparatus, a drive circuit, and a drive method that can reduce electric current fluctuation.
It is a general object of the present invention to provide a plasma display apparatus, a drive circuit, and a drive method that substantially obviate one or more problems caused by the limitations and disadvantages of the related art.
Features and advantages of the present invention will be presented in the description which follows, and in part will become apparent from the description and the accompanying drawings, or may be learned by practice of the invention according to the teachings provided in the description. Objects as well as other features and advantages of the present invention will be realized and attained by a plasma display apparatus, a drive circuit, and a drive method particularly pointed out in the specification in such full, clear, concise, and exact terms as to enable a person having ordinary skill in the art to practice the invention.
To achieve these and other advantages in accordance with the purpose of the invention, the invention provides a circuit for driving a plasma display panel in which display cells are constituted at least by a set of electrodes including first electrodes extending in a first direction, second electrodes extending in the first direction, and third electrodes extending in a second direction substantially perpendicular to the first direction. The circuit includes a first driver circuit configured to drive the first electrodes, a second driver circuit configured to drive the second electrodes, a third driver circuit configured to drive the third electrodes, and a control circuit configured to control the first through third driver circuits such as to perform an address drive operation and a sustain drive operation simultaneously in parallel by performing the sustain drive operation to apply a sustain voltage between a first electrode and a second electrode adjacent to each other so as to sustain electric discharge at the display cells while performing the address drive operation to successively apply a scan voltage to the first electrodes and apply an address voltage to the third electrodes so as to select the display cells.
According to another aspect of the present invention, a method of driving a plasma display panel, in which display cells are constituted at least by a set of electrodes including first electrodes extending in a first direction, second electrodes extending in the first direction, and third electrodes extending in a second direction substantially perpendicular to the first direction, includes a reset drive step of applying a reset voltage to the first electrodes and the second electrodes, an address drive step of successively applying a scan voltage to the first electrodes and applying an address voltage to the third electrodes so as to select the display cells, and a sustain drive step of applying a sustain voltage between a first electrode and a second electrode adjacent to each other so as to sustain electric discharge at the display cells, wherein the address drive step and the sustain drive step are performed at least partially simultaneously in parallel.
According to another aspect of the present invention, a plasma display apparatus includes a plasma display panel in which display cells are constituted at least by a set of electrodes including first electrodes extending in a first direction, second electrodes extending in the first direction, and third electrodes extending in a second direction substantially perpendicular to the first direction, a first driver circuit configured to drive the first electrodes, a second driver circuit configured to drive the second electrodes, a third driver circuit configured to drive the third electrodes, and a control circuit configured to control the first through third driver circuits such as to perform an address drive operation and a sustain drive operation simultaneously in parallel by performing the sustain drive operation to apply a sustain voltage between a first electrode and a second electrode adjacent to each other so as to sustain electric discharge at the display cells while performing the address drive operation to successively apply a scan voltage to the first electrodes and apply an address voltage to the third electrodes so as to select the display cells.
According to at least one embodiment of the present invention, provision is made to simultaneously perform the address drive operation and the sustain drive operation in parallel with respect to the plasma display panel. This can ensure the provision of a sufficient address drive period and a sufficient sustain drive period, and achieves drive operations with reduced current fluctuation. Further, the increase of the speed of drive operation and the shortening of drive time serve to improve display performance such as the capability of grayscale representation and the capability of high-luminance display.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
In the following, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in
Drive operation starts with the first sub-frame SF1. At the start of the sub-frame, the reset drive operation is performed with respect to all the display lines, thereby setting the state of all the display cells to the initial state. The same applies in the case of the following sub-frames SF2 through SF10. That is, the reset drive operation is performed at the start of each sub-frame to initialize all the display cells.
Following the reset drive operation, the address and sustain drive period comes in which an address (scan) operation and a sustain operation are successively performed with respect to the display lines L1 through L10. In
In
For the display line L2, for example, the duration of the sustain drive operation is the second longest for the first sub-frame SF1, and is the longest for the second sub-frame SF2. The duration of the sustain drive operation is the shortest in the third sub-frame SF3. The length of the sustain drive operation increases gradually on a step-by-step manner from the third sub-frame SF3 to the tenth sub-frame SF10. With this arrangement, 10 sub-frames having sustain drive operations of 10 different lengths are provided.
In this manner, 10 sub-frames having sustain drive operations of 10 different durations are provided for each display line. Sub-frames forming a desired combination of sub-frames selected from these 10 sub-frames are caused to emit light, thereby making it possible to represent a desired gray scale. When looking at the entirety of the display lines L1 through L10, the address drive operation and the sustain drive operation are simultaneously performed in parallel. That is, the drive period is not clearly divided into an address period and a sustain drive period.
In the present invention as described above, the address drive operation and the sustain drive operation are concurrently performed in parallel in the address and sustain drive operation, thereby significantly reducing the time required for the address and sustain drive operation compared with the case in which the address period and the sustain drive period are separately provided to perform the address drive operation and the sustain drive operation separately from each other as in the related-art configuration. Further, the sustain drive operation is being performed in at least some of the display lines during the most period of any given sub-frame, so that sudden fluctuation in electric currents can be suppressed.
Each sub-frame is subjected to timing control using drive timings T0 through T11. At the start timing T0 of each sub-frame, the reset drive operation R is performed with respect to all the display lines L1 through L10, thereby setting the state of all the display cells to the initial state. Following the reset drive operation R, the address and sustain drive period comes in which an address (scan) operation A and a sustain drive operation S are performed with respect to each of the display lines.
In the address and sustain drive period of the sub-frame SF1, as shown in
In so doing, the address drive operation A is performed for L2 at the timing T2, and, at the same time, the sustain drive operation S is performed in parallel for L1 for which the address drive operation has already been completed. By the same token, the address drive operation A is performed for L3 at the timing T3, and, at the same time, the sustain drive operation S is performed in parallel for both L1 and L2 for which the address drive operation has already been completed. Such operations are repeated until T10.
At the last timing T11, the sustain drive operation S is performed for all the display lines L1 through L10 inclusive of L10 for which the address drive operation was completed at the immediately preceding timing. After this sustain drive operation, the address and sustain drive period comes to an end.
With the address and sustain drive operation performed as described above for the sub-frame SF1, the sustain drive operation S is performed 10 times through once with respect to the display lines L1 through L10, respectively. This achieves the provision of gray scales based on the sustain drive operations having different durations for respective display lines.
Transition is then made from the sub-frame SF1 to the sub-frame SF2 shown in
Other operations are the same as in the case of the sub-frame SF1, so that the sustain drive operation S is performed on the display lines for which the address drive operation A is completed, until the drive operation comes to an end at the timing T11. With the address and sustain drive operation performed as described above for the sub-frame SF2, the sustain drive operation S is performed once with respect to the display line L1, and the sustain drive operation S is performed 10 times through 2 times with respect to the display lines L2 through L10, respectively. This achieves the provision of gray scales based on the sustain drive operations having different durations for respective display lines while making the number of sustain drive operations for each display line different from those of SF1.
In the sub-frame SF3 shown in
Through the operations as described above, the numbers of sustain drive operations from 1 to 10 are assigned to each one of the display lines after the completion of one frame. Further, sub-frames may be combined to perform a desired number of sustain drive operations from the smallest number 1 to the largest number 55 (=1+2+3+ . . . +10) with respect to any given display line. This achieves 56 gray scales including the state of no light emission.
Each of the sub-frames SF1 through SF10 described above is comprised of the 11 timings T1 through T11. This number is limiting, and the number of sustain drive operations S may be increased as appropriated. The configuration of the present invention thus possesses great latitude in gray scale representation.
A drive circuit shown in
The control circuit 200 receives a clock signal CLK, display data D, a vertical synchronizing signal VSYNC, a horizontal synchronizing signal HSYNC, etc., from an external source, and generates control signals for controlling the panel operation based on the received signals and data. To be specific, the display data control unit 211 receives the display data D for storage in the frame memory 212, and generates an address control signal responsive to the display data D stored in the frame memory 212 in synchronization with the clock signal CLK. The address control signal is supplied to the address driver circuit 201. The Y-electrode control unit 213 generates a Y-electrode-scan driver control signal for controlling the Y-electrode scan driver circuit 202 and the Y-electrode common-reset-voltage-waveform generating circuit 203 in synchronization with the vertical synchronizing signal VSYNC and the horizontal synchronizing signal HSYNC. The X-electrode control unit 214 generates an X-electrode driver control signal for controlling the X-electrode driver circuit 204 and the X-electrode common-reset-voltage-waveform generating circuit 205 in synchronization with the vertical synchronizing signal VSYNC and the horizontal synchronizing signal HSYNC.
The address driver circuit 201 operates in response to the address control signal supplied from the display data control unit 211, and applies address voltage pulses responsive to the display data to address electrodes A1 through Am. The Y-electrode scan driver circuit 202 operates in response to the scan driver control signal supplied from the Y-electrode control unit 213, and drives scan electrodes (Y electrodes) Y1 through Yn independently of each other. While the Y-electrode scan driver circuit 202 successively drives the scan electrodes (Y electrodes) Y1 through Yn, the address driver circuit 201 applies address voltage pulses to the address electrodes A1 through Am, thereby selecting cells to emit light so as to control display/non-display (selected-state/unselected-state) of each cell 103.
The Y-electrode scan driver circuit 202 controls the Y electrodes Y1 through Yn independently of each other, and applies sustain voltage pulses specific to respective display lines to the Y electrodes Y1 through Yn so as to perform sustain drive operations different for respective display lines as shown in
In the related-art configuration shown in
The switch elements 221 and 222 are provided for the purpose of applying scan voltage pulses (−Vd level) for address drive operation to the Y electrode Yi. At the time of address drive operation, the switch elements 221 and 222 are placed in the nonconductive state and conductive state, respectively, for a predetermined duration, thereby applying a voltage −Vd having a predetermined pulse width as a scan voltage pulse to the Y electrode Yi. The switch elements 223 and 224 are provided for the purpose of applying sustain voltage pulses (Vs level) for sustain drive operation to the Y electrode Yi. At the time of sustain drive operation, the switch elements 223 and 224 are placed in the conductive state and nonconductive state, respectively, for a predetermined duration, thereby applying a voltage Vs having a predetermined pulse width as a sustain voltage pulse to the Y electrode Yi. Such sustain voltage pulse is applied repeatedly.
The Y electrode Yi is coupled to the Y-electrode common-reset-voltage-waveform generating circuit 203 via a diode 227. The Y-electrode common-reset-voltage-waveform generating circuit 203 generates a reset voltage, and supplies the common reset voltage to all the Y electrodes Y1 through Yn.
The switch elements 225 and 226 are provided for the purpose of applying sustain voltage pulses (Vs level) for sustain drive operation to the X electrode Xi. At the time of sustain drive operation, the switch elements 225 and 226 are placed in the conductive state and nonconductive state, respectively, for a predetermined duration, thereby applying a voltage Vs having a predetermined pulse width as a sustain voltage pulse to the X electrode Xi. Such sustain voltage pulse is applied repeatedly.
The X electrode Xi is coupled to the X-electrode common-reset-voltage-waveform generating circuit 205 via a diode 228. The X-electrode common-reset-voltage-waveform generating circuit 205 generates a reset voltage, and supplies the common reset voltage to all the X electrodes X1 through Xn.
In the present invention, the switch elements 223 and 224 for applying sustain voltage pulses for sustain drive operation to the Y electrode Yi are controlled independently of the switch elements for applying sustain voltage pulses for sustain drive operation to other Y electrodes. Namely, the signals supplied to the control gates of the switch elements 223 and 224 are different for each Y electrode. Further, the switch elements 225 and 226 for applying sustain voltage pulses for sustain drive operation to the X electrode Xi are controlled independently of the switch elements for applying sustain voltage pulses for sustain drive operation to other X electrodes. Namely, the signals supplied to the control gates of the switch elements 225 and 226 are different for each X electrode.
After this, drive pulses are applied to each electrode in the address and sustain drive period.
The address drive operation is performed at the timing Ti with respect to the display line Li. To be specific, a scan voltage pulse (−Vd level) is applied to the Yi electrode, and, at the same time, an address voltage pulse (Va level) is applied to selected address electrodes. This creates wall charge at the selected display cells on the display electrode Yi, and causes these cells to enter the state of sustained light emission. Thereafter, sustain voltage pulses (Vs level) are applied between the Yi electrode and the Xi electrode in an alternating manner, thereby reversing the created wall charge to continue the state of sustained light emission.
With respect to the display line Li+1, the address drive operation is performed at timing Ti+1, followed by performing sustain drive operations between the Yi+1 electrode and the Xi+1 electrode in an alternating manner. In so doing, the address voltage pulses (Va level) applied to the address electrodes for the purpose of the display line Li+1 are driven at the same timing as the sustain voltage pulse (Vs level) applied to the electrode Yi that has already been placed in the state of sustain drive operation. In this case, there may be a concern that the address voltage pulses for Li+1 affect the sustain drive operation for Li.
In an example of
In
It should be noted that in the waveforms of basic drive operations shown in
When 10-fold division is made, every 50 lines of all the display lines are put together from the top to the bottom so as to generate 10 blocks. Within each block, all the display lines are subjected to the sustain drive operation having the same duration and the same number of drive operations. For all the display lines L1 through L50, for example, the number of sustain drive operations is 451 in the first sub-frame SF1. For all the display lines L151 through L200, for example, the number of sustain drive operations is 128 in the second sub-frame SF2.
In
The length of one frame needs to be set to 16.667 ms as previously described, so that one frame becomes 1.667 ms. This length of one sub-frame is divided into the reset drive period and the address and sustain drive period. Further, the address and sustain drive period is divided into 501 timings T1 through T501, which is the sum of 500 address drive operations for the 500 display lines and one sustain drive operation for the display line for which the last address drive operation is performed. One timing corresponds to one sustain drive voltage pulse (i.e., one sustain drive operation).
As shown in
The block for which the address drive operation is performed next is the display lines L51 through L100. After the address drive operation is performed with respect to the display line L100 at the timing T100, the sustain drive operation is performed with respect to the display line L100 by starting from the timing T101. In so doing, the number of sustain drive operations in respect of the display line L100 is 401 at the maximum. In this example, however, the number of sustain drive operations is set to 256, which is a power-of-two value that is easy to control. Namely, with respect to each and every one of the display lines L51 through L100, the sustain drive operation is started at the timing immediately following the address drive operation, and is performed 256 times.
As shown in
As shown in
As shown in
In this manner, the 500-display-line panel is divided tenfold, and 10 sub-frames are used in the first embodiment. A desired combination of sub-frames are then selected from these 10 sub-frames, thereby achieving the displaying of 963 gray scales at the maximum (=451+256+128+64+32+16+8+4+2+1+1 [corresponding to the turned-off state]).
When 10-fold division is made, every 50 lines of all the display lines are put together from the top to the bottom so as to generate 10 blocks in the same manner as in the first embodiment. Within each block, all the display lines are subjected to the sustain drive operation having the same duration and the same number of drive operations. In the second embodiment, the number of sustain drive operations is set to 512 for the display-line block that is subjected to the first address drive operation.
As shown in
In this manner, when the 500-display-line panel is divided tenfold, and 10 sub-frames are used in the second embodiment, the address and sustain drive period is divided into the timings T1 through T562, which correspond to the number required to achieve the displaying of 1024 gray scales. A desired combination of sub-frames are then selected from these 10 sub-frames, thereby achieving the displaying of 1024 gray scales at the maximum (=512+256+128+64+32+16+8+4+2+1+1 [corresponding to the turned-off state]).
When 16-fold division is made, every 32 lines of all the display lines are put together from the top to the bottom so as to generate 16 blocks. Within each block, all the display lines are subjected to the sustain drive operation having the same duration and the same number of drive operations. In the third embodiment, the number of sustain drive operations is set to 256 for the first display-line block through the sixth display-line block where the first display-line block is subjected to the first address drive operation. Further, the number of sustain drive operations is set to 128 for the seventh display-line block through the ninth display-line block. The numbers of sustain drive operations for tenth through sixteenth display-line blocks are set to 64, 32, 16, 8, 4, 2, and 1, respectively.
As shown in
In this manner, the 512-display-line panel is divided sixteen-fold, and 16 sub-frames are used in the third embodiment, with the address and sustain drive period being divided into the timings T1 through T512. A desired combination of sub-frames are then selected from these 16 sub-frames, thereby achieving the displaying of 2048 gray scales (=256×6+128×3+64+32+16+8+4+2+1+1 [corresponding to the turned-off state]).
The settings of the numbers of sustain drive operations for each sub-frame described above correspond to a case in which power-of-two values that are relatively easy to control are selected and combined to achieve the displaying of 2048 gray scales that is possible to provide the grayscale representation of the highest level for practical purposes. If the power-of-two values are not insisted upon, the number of sustain drive operations applicable to each display line block is 481 at the maximum (i.e., 513-32). The displaying of gray scales larger in number than 2048 gray scales is of course possible by using such number of sustain drive operations in combination and/or by setting the number of sustain drive operations to 256 for the seventh display-line block.
In the fourth embodiment as described above, a display-line block is formed by selecting every tenth display line, and the address drive operation is successively performed in a predetermined block order, with the same number of sustain drive operations being used in the same block. In the present invention, when display lines are selected to constitute a display-line block, such selection is not limited to a specific method of selection. Display lines may be put together by use of any desired method to constitute a display-line block.
In the fourth embodiment described above, a display-line block does not form a single lump, but has the display lines thereof spaced apart in an evenly distributed manner, so that the numbers of sustain drive operations for adjacent display lines are different from each other, thereby achieving more smoother displaying of gray scales in the direction in which display lines are arranged side by side.
The fifth embodiment differs from the first embodiment in that the sustain drive waveforms as shown in
The P-th Y driver 301-P receives a clock signal YCLK-P, a scan timing signal YD-SCAN-P, and a Y-electrode sustain-drive-timing signal YD-SUS-P from the Y-electrode control unit 213. The Y-electrode control unit 213 supplies the scan timing signal YD-SCAN-P together with the clock signal YCLK-P to the Y driver 301-P at the time of address drive operation with respect to the P-th block. The Y-electrode control unit 213 further supplies the Y-electrode sustain-drive-timing signal YD-SUS-P together with the clock signal YCLK-P to the Y driver 301-P at the time of a sustain drive operation with respect to the P-th block. Further, a common control signal is supplied in common to the Y drivers 301-1 through 301-Q.
The sustain-drive shift register 311 includes k flip-flops S1 through Sk. The sustain-drive shift register 311 receives the Y-electrode sustain-drive-timing signal YD-SUS-P from the Y-electrode control unit 213, and makes the Y-electrode sustain-drive-timing signal YD-SUS-P propagate through the flip-flops S1 through Sk by storing the signal in the flip-flops successively. This successive storing and propagation are performed in synchronization with the clock signal YCLK-P.
The scan-drive shift register 312 includes k flip-flops S1 through Sk. The scan-drive shift register 312 receives the scan timing signal YD-SCAN-P from the Y-electrode control unit 213, and allows the scan timing signal YD-SCAN-P to propagate through the flip-flops S1 through Sk by storing the signal in the flip-flops successively. This successive storing and propagation are performed in synchronization with the clock signal YCLK-P.
The high-voltage output circuits 313-1 through 313-k receive the respective outputs of the flip-flops S1 through Sk of the sustain-drive shift register 311, and also receive the respective outputs of the flip-flops S1 through Sk of the scan-drive shift register 312. Further, the common control signal is supplied in common to the high-voltage output circuits 313-1 through 313-k.
Each of the high-voltage output circuits 313-1 through 313-k drives a Y electrode by the address drive voltage when the signal received from the corresponding flip-flop of the scan-drive shift register 312 is in the asserted state. This achieves the address drive (scan drive) operation. Further, each of the high-voltage output circuits 313-1 through 313-k drives a Y electrode by the sustain drive voltage in response to the common control signal when the signal received from the corresponding flip-flop of the sustain-drive shift register 311 is in the asserted state. With this arrangement, the sustain drive operation is achieved. In this manner, the sustain drive timings of the high-voltage output circuits 313-1 through 313-k are controlled in response to respective timing control signals (i.e., the Y-electrode sustain-drive-timing signal YD-SUS-P propagating through the sustain-drive shift register 311) that indicate different timings.
Further, the Y electrode Y1 is subjected to the sustain drive operations (voltage: Vs) at the timing responsive to the Y-electrode sustain-drive-timing signal YD-SUS-1 (i.e., at the timing corresponding to the HIGH period of the Y-electrode sustain-drive-timing signal YD-SUS-1). Thereafter, as the Y-electrode sustain-drive-timing signal YD-SUS-1 propagates through the sustain-drive shift register 311, the sustain drive operations (voltage: Vs) are successively performed with respect to the Y electrodes Y2, Y3, . . . , and so on. The sustain drive pulses for the even-number Y electrodes are generated in response to the pulses of a common control signal YSUS-EVEN, and the sustain drive pulses for the odd-number Y electrodes are generated in response to the pulses of a common control signal YSUS-ODD.
The P-th X driver 401-P receives a clock signal XCLK-P and an X-electrode sustain-drive-timing signal XD-SUS-P from the X-electrode control unit 214. The X-electrode control unit 214 supplies the X-electrode sustain-drive-timing signal XD-SUS-P together with the clock signal XCLK-P to the X driver 401-P at the time of sustain drive operation with respect to the P-th block. Further, a common control signal is supplied in common to the X drivers 401-1 through 401-Q.
The sustain-drive shift register 411 includes k flip-flops S1 through Sk. The sustain-drive shift register 411 receives the X-electrode sustain-drive-timing signal XD-SUS-P from the X-electrode control unit 214, and makes the X-electrode sustain-drive-timing signal XD-SUS-P propagate through the flip-flops S1 through Sk by successively storing the signal in the flip-flops starting with the flip-flop S1. This successive storing and propagation are performed in synchronization with the clock signal XCLK-P.
The high-voltage output circuits 413-1 through 413-k receive the outputs of the respective flip-flops S1 through Sk of the sustain-drive shift register 411. Further, the common control signal is supplied in common to the high-voltage output circuits 413-1 through 413-k.
Further, each of the high-voltage output circuits 413-1 through 413-k drives an X electrode by the sustain drive voltage in response to the common control signal when the signal received from the corresponding flip-flop of the sustain-drive shift register 411 is in the asserted state. With this arrangement, the sustain drive operation is achieved. In this manner, the sustain drive timings of the high-voltage output circuits 413-1 through 413-k are controlled in response to respective timing control signals (i.e., the X-electrode sustain-drive-timing signal XD-SUS-P propagating through the sustain-drive shift register 411) that indicate different timings.
Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.
In the above disclosure, the embodiments of the present invention have been described with reference to a three-electrode-type flat-plane-discharge AC-PDP panel as an example. The present invention is not limited to this configuration, and is equally applicable to two-electrode-type AC-PDP that utilizes gas discharge.
The present application is based on Japanese priority application No. 2005-365098 filed on Dec. 19, 2005, with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | Kind |
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2005-365098 | Dec 2005 | JP | national |