JP3117500B2 - Driving method of AC type plasma display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for performing a memory display, in particular, an AC type plasma display and a DC.
The present invention relates to a method of driving a panel display device such as a memory type plasma display and an active matrix type LCD (TFT).

[0002]

2. Description of the Related Art FIG. 6 illustrates a basic configuration of an AC type plasma display as a prior art.
Have discharge cells C arranged in a matrix. Vertical electrodes X _{1 to} Xm and horizontal electrodes Y _{1 to} Ym for generating a discharge in the discharge cells C have a vertical electrode driver IC 3 and a horizontal electrode, respectively. A high voltage output having a drive waveform as shown in FIG. 7 described below is applied from the driver IC 4. Reference numeral 1 denotes a power supply circuit for each of the driver ICs 3 and 4, and 2 denotes a control circuit for each of the driver ICs 3 and 4. The control circuit 2 includes a horizontal and vertical synchronization signal and display data (which discharge cell The interface signal including data indicating whether or not to emit light is input. In this way, the data of which discharge cell is to selectively emit light is displayed by aligning the data input from the outside in this manner to the electrode of which line and when. Control (display data or scan control) is performed such as whether to output.

FIG. 7 is a timing chart illustrating driving waveforms in the apparatus shown in FIG.
The driving waveform in the horizontal synchronization period is shown. FIG. 7A shows that a certain vertical electrode (X
7B shows a driving waveform for one driving cycle in the vertical electrode waveform applied to the vertical electrode waveform. FIG. 7B shows the driving signal from the horizontal electrode driver 4 for a certain horizontal electrode (in this case, the display data for the discharge cell). One drive cycle (display for that line) in a horizontal electrode waveform applied to a line to be rewritten (in this case, display data is sequentially rewritten for each line, which is Yn) 2 shows a drive waveform for a drive cycle in which data is rewritten).

As shown in FIG. 7, the driving waveform is divided into an address period and a sustain discharge period. In the address period, discharge of a corresponding row (line) is performed by a write voltage applied by the vertical electrode and the horizontal electrode. Writing is performed on the cell in accordance with the display data (in other words, whether or not writing is performed on each discharge cell in the corresponding line is determined in accordance with the display data).

That is, in a drive cycle in which display data is rewritten to the line, first, a narrow erase pulse EP shown in a horizontal electrode waveform Yn (FIG. 7B) of the line is used in a previous frame. An erasing discharge for forcibly terminating the sustaining discharge is performed (that is, all the discharge cells of the line which have been emitting light in the previous frame are once erased), and then a write pulse WP is applied to the line (MP is a sustaining voltage which will be described later). Pulse).
At this time, a certain vertical electrode waveform Xn (FIG. 7A)
The write cancel pulse WC corresponding to the display data
Is output (ie, WC is off) or is output (ie, WC is on),
It is determined whether writing is performed (that is, discharge light emission) is performed on the discharge cell C located at the intersection of the line (horizontal electrode) Yn and the vertical electrode Xn, or writing is not performed (that is, erased).

Note that MP shown in the vertical electrode waveform Xn and the horizontal electrode waveform Yn is a sustain pulse, and is applied to each of the electrodes when the discharge cell C is written as described above. (In a driving cycle in which the display data for the line is not rewritten, there is no address period in the horizontal electrode waveform Yn of the line, and only the sustain pulse MP is applied at a predetermined period). The state is maintained (that is, the discharge state is maintained unless data is rewritten in the address period of the next line (next frame) in the address line). On the other hand, when the writing is not performed on the discharge cell C as described above, the sustain discharge is not performed even if the sustain pulse MP is applied thereafter (that is, the data is rewritten in the next address period in the corresponding line). Discharge does not occur unless the operation is performed). Note that the vertical electrode waveform Xn has an address period for each driving cycle.
Whether or not data is written to each discharge cell in the line Yn that is being rewritten at that time is determined depending on whether or not C is output.

FIG. 7C shows a cell voltage waveform (Yn-Xn) when display data is written to a corresponding cell in the driving cycle (that is, when the write cancel pulse WC is off). (C ') shows a cell voltage waveform (Yn-Xn) when display data is not written in the corresponding cell (that is, when the write cancel pulse WC is on).

That is, in the case of FIG. 7C, since the pulse WC is turned off, a discharge occurs by applying the write pulse WP, and thereafter, a dielectric substance is formed on the electrode of the discharge cell. Charge (wall charge) is accumulated through the layer (ie, on the surface of the dielectric layer) (ie, at time T in FIG. 7 (C), a write discharge is generated in the cell beyond the discharge starting voltage, and wall charge is formed. ). As a result, when the sustain pulse MP is applied next, the sustain voltage (voltage of the sustain pulse) applied from the driver IC 3 or 4 and the potential due to the wall charges are added inside the cell,
The effective voltage exceeds the discharge start voltage (that is, becomes a voltage corresponding to the write pulse WP), and a discharge occurs. Then, by applying the sustain pulse MP while reversing the polarity, the discharge is continued and the light emission is repeated, resulting in a large luminance in total. The sustain discharge (discharge by the sustain pulse) is maintained as long as the display data is not rewritten in the address period of the next line (next frame) as described above.

On the other hand, in the case of FIG. 7 (C '), since the pulse WC is turned on, the effective voltage of the cell at time T in FIG. 7 (C') becomes (WP-WC). (FIG. 7
(Shown as NWP in (C ')), the voltage required for writing is not reached, and writing to the cell is not performed.
Therefore, even if the sustain pulse MP is subsequently applied, as described above, there is no sustain discharge due to the sustain pulse, and as long as display data is not rewritten in the address period of the next line (next frame) in the corresponding line, the sustain discharge is not performed. No discharge occurs in the cell.

In FIG. 7, the sustain discharge in the previous frame is forcibly terminated by the erase pulse EP once in the address period of the drive cycle in which the display data is rewritten for each line, and then in the current frame. The display waveform is such that display data is written only in necessary discharge cells in the line and discharge is performed in the cell. Instead, display is performed on all discharge cells in the line once in the address period. It is also possible to write the data and then erase the necessary discharge cells in the line in the current frame (see FIG. 10 described later).

As described above, the scanning of the panel is performed by CR
Unlike the case of T, in which display is performed by irradiating electrons one point at a time from left to right and further from top to bottom (dot sequential scanning), the dots in one line are displayed simultaneously with the display data (in the case of FIG. Is a line-sequential scan in which the data of whether the write cancel pulse WC is turned off or on) is written, and the operation is repeated from the top to the bottom line.

FIG. 8 is a conventional panel drive timing diagram for the apparatus shown in FIG. 6. The scan line shown in FIG. 8 is for one frame period (1 In each vertical synchronization period, the driving cycle in which data is rewritten to the discharge cells in each line (that is, the driving cycle with the address period) repeatedly moves from the upper line to the lower line with the passage of time. Then show the relationship going. Further, in FIG. 8, the image displayed on the first line in the first frame (when all the discharge cells on the first line are turned on, only the discharge cells connected to a predetermined vertical electrode are turned on among them). May be displayed), but is moved to and displayed on the second line in the second frame. That is, the discharge cells that were lit on the first line in the first frame were rewritten in the second frame, so that the discharge cells on the first line (the discharge cells lit in the first frame) Are turned off in the second frame, and immediately thereafter, in the second frame (that is, at the time when the time t has elapsed after the discharge cells in the first line are turned off), the corresponding discharge cells in the second line (as described above) 5 shows a case where all the discharge cells in the second line or the discharge cells connected to a predetermined vertical electrode among them are lit.

As described above, data written once is rewritten in the next frame unless gradation display (shown in FIG. 9 described later) controlled by the ratio of the display time in the frame is performed. Until, keep displaying. In the AC type plasma display, the total luminance is improved by effectively using the time in the frame and repeating the sustain discharge.

In the case of gray scale display, as shown in the drive timing chart of FIG. 9, the time in a frame is divided into several periods (subfields) having different display times, and the luminance is determined by the combination. The difference (gradation) is displayed.
That is, in the example shown in FIG. 9, the frame (one vertical synchronization period) is divided into three subfields 1, 2, and 3, and the time ratio of the subfields 1, 2, and 3 is 1: 2. : 4 and an arbitrary subfield is selected and turned on as shown in FIG. 9 (that is, for each line (1 to 480 lines in this case), each of the scan lines 1, 2, and 3 is turned on). The first drive cycle that moves in time is a drive cycle for rewriting data for each line (that is, a drive cycle with an address period), thereby providing eight stages of 0 to 7 for the discharge cells of each line. Brightness can be selected. When the time ratio of each subfield is set as described above, the discharge cells of each line are weighted along the scan lines 1, 2, and 3 (the 8 gray scales are used). In such a case, display data (weighted 1: 2: 4) is written in the drive cycle for the rewriting.

FIG. 10 shows a timing chart of input data and an n-line drive waveform as another conventional example.
As described above, display data is once written in all the discharge cells in the line during the address period,
Next, a case is shown in which the other discharge cells are turned off except for the discharge cells to be turned on in this frame. That is, for each driving cycle (for example, about 40 μs in one horizontal synchronization period) shown in FIG.
As shown in FIG. 10B, data for each line (data to be supplied to each vertical electrode, in this case, FIG. 10C)
, Erase erase data (erase cancel pulse) EC for canceling the narrow erase pulse EP shown in FIG. That is, for example, FIG.
The data of the n-th line shown in (1) is the data for each discharge cell on the n-th line, which data EC is to be inserted into which column (when the data EC is inserted, the erase pulse EP When the corresponding discharge cell is canceled and the corresponding discharge cell is turned on, the sustain discharge is continued until the data is rewritten. On the other hand, when the data EC is not input, the erase pulse EP becomes valid and the corresponding discharge cell becomes effective. Is turned off, and no sustain discharge is performed until the data is rewritten thereafter).

The n-line driving waveform shown in FIG. 10C is a horizontal electrode waveform corresponding to FIG. 7B, and the driving cycle at the center in FIG. This is a driving cycle for rewriting data to a line.
Here, in the example shown in FIG. 10 (C), unlike the case of FIG. 7, as described above, the write pulse WP is applied to all the discharge cells for the n-line once to perform the write, and then the fine At the time when the width erasing pulse EP is applied, whether or not to perform writing is determined according to whether or not the erase cancel data (erase cancel pulse) EC from the vertical line side is applied. Undischarged discharge cells will be erased. MP shown in FIG. 10C is the above-mentioned discharge sustaining pulse. For example, the data of the n-th line shown in FIG. 10B is temporarily latched after being transferred to the vertical electrode driver, and is delayed by one driving cycle.
It controls whether or not the erase pulse EP in the driving waveform shown in FIG. 10C is cancelled. In this way, the display of the n-th line (in other words, data rewriting for each discharge cell of the n-th line) is performed in the driving cycle at the center in FIG. A discharge current flows as shown in FIG. In the figure, Tvsync is one frame period (one vertical synchronization period).
6.7 ms (1/60 second).

When the AC type plasma display is driven by a memory as described above, data is written to all lines other than a line (refresh line) in which display rewriting is performed sequentially along a scan line. The discharged discharge cell is discharging and lighting, and the discharge is repeated at intervals of, for example, 5 to 10 μs. Similar driving is performed also in a DC memory type plasma display or an active matrix type LCD to improve luminance and contrast.

[0018]

As described above, since the panel display which performs memory display effectively uses the time in a frame, the display until the display of the corresponding line is rewritten in the next frame is performed. Has continued. Therefore, when a moving image (movement of a character, a graphic, or the like) is displayed, the line may appear double.

FIG. 11 explains the above phenomenon. FIG. 11 shows a vertical line moving from right to left at the moment when the n-th line is rewritten (in FIG. 11, a hatched circle is lit). (A white circle indicates a dot that was lit in the previous frame). Here, in the n-th line, in the data rewriting drive cycle, the data of the previous frame is erased (that is, the dot of the hatched circle on the right side of the n-th line is erased), and the dot one dot left is erased at the next moment. At that moment, it looks as if two dots are lit, and the repetition causes the vertical line to appear double. Actually, when a display is moved such as a cursor movement or a smooth scroll display as when a mouse is moved, such an illusion phenomenon that a line appears double appears as described above. Also, in the case where video display is performed using gradation display, it is conceivable that a double image of a contour may occur in a moving image.

The present invention has been made in order to solve such a problem, and even when the display movement such as the above-described smooth scroll display is performed, a double image of a moving image (for example, a line) or a double image of a contour is displayed. And the like are prevented from occurring.

[0021]

According to one embodiment of the present invention, there is provided a display period for sequentially rewriting display data for a display element of a line for each line within each frame period. AC type plastic with
A method for driving a zuma display device, comprising:
Each driving method is provided of an AC-type plasma display device according to claim <br/> be controlled to set between hidden life erasing operation for all display elements sequentially the lines for each line You. According to another aspect of the present invention,
A method for driving a display device is provided, wherein the display period and the non-display period are set alternately for each frame. According to still another aspect of the present invention, in each frame period, the display data for the display element of the line is sequentially rewritten for each line, and the sustain discharge for the rewritten display element is performed. AC plasma display with a display period for lighting the discharge cells by performing
A method of driving a spray device, for each frame, without a sustain discharge in all display elements, AC-type plasma display apparatus and controls to set between hidden period for turning off the display cell Is provided.

[0022]

According to the above arrangement, by limiting the display period in a frame and forcibly providing a non-display period, the period immediately before starting a new display in the next frame is set as the display suspension period. The phenomenon of double reflection can be prevented. Alternatively, by alternately providing the display period and the non-display period for each frame, the non-display period becomes a display suspension period, and the phenomenon of double image reflection can be prevented.

[0023]

FIG. 1 shows a panel drive timing diagram as one embodiment of the present invention, which is characterized in that a forced erase scan is performed in the middle of each frame. That is, the first scan (indicated by scan line 1) in each frame is performed in order to sequentially write display data on each line, and the scan line 1 corresponds to the scan line in FIG. I do. And the scan
In the first drive cycle (drive cycle in which rewriting is performed) of each line sequentially along the line 1, a drive wave as described with reference to FIG. 7 is applied to each discharge cell of the line, so that display data is written. The discharge cells in which the display data has been written in this manner are sustained in the subsequent drive cycle during the display period shown in FIG. 1 and are lit.

Next, in each frame, a second scan (indicated by scan line 2) is performed in order to sequentially perform a forced erase operation on each line. That is, in the first driving cycle of each line sequentially along the scan line 2, the horizontal electrode waveform (that is, the erase pulse EP exists but the write pulse WP is applied to the line) as shown in FIG. Is applied, and the erase pulse EP turns off all the discharge cells in the line, thus setting the display interruption period.

The write cancel pulse WC present in the vertical electrode waveform (shown in FIG. 2A) in this drive cycle functions as display data for another line during the display period. It is determined whether or not to write data to each discharge cell in another line in a display cycle at that time and in a driving cycle in which data rewriting is performed, based on whether or not the pulse WC is output. It is determined. Note that FIG.
In the case of performing the gray scale display in the drive timing chart shown in FIG. 1, the display period in FIG. 1 may be divided into several subfields as in the case shown in FIG.
One frame (one vertical synchronization period) is usually 20 ms.
(1/50 second) to 16.7 ms (1/60 second).

FIG. 3 shows the relationship between input data and internal data as another embodiment of the present invention. The display period (lighting period) and the display interruption period (light-off period) are set for each frame. This is set alternately (for example, in odd frames and even frames). To this end, as shown in FIG. 3A, the frame frequency is made approximately twice the conventional one (ie, one frame period is set to, for example, 10 ms (1/100 second)).
For example, display for one screen is performed in an odd frame (that is, input data for each line as described with reference to FIG. 10B is taken as it is as internal data (that is, externally transferred to the vertical electrode driver), As described with reference to FIGS. 10B and 10C, it is determined whether to turn on the corresponding discharge cell according to the presence or absence of the erase cancel data EC. , The internal data transferred to the vertical electrode driver is set to “0” (that is, the erase cancel data EC is set to “0” for all the discharge cells of each line, and the erase pulse E described in FIG.
P is made valid), and all the discharge cells of each line are turned off (see FIGS. 3B and 3C). In other words, in the even-numbered frames, the erase-cancel data EC as the display data is all set to the ground level (as blank data), and the display is interrupted for all the discharge cells in each line.

FIG. 4 is a timing chart of the input data and the n-line driving waveform in the odd-numbered frame of the embodiment described with reference to FIG. 3, and shows the relationship between the input data and the n-line driving waveform in the odd-numbered frame. FIG.
This is equivalent to the case described in (B) and (C). (Since only one frame period is set to about 10 ms as described above, one driving cycle period (one horizontal scanning period) becomes about 2 ms.
4 μs). That is, in the odd-numbered frame, each discharge cell of each line applies the erase pulse EP (FIG. 4C) in its data rewriting drive cycle.
At the time of application of erase cancel data (erase cancel pulse) EC (from the vertical line side, for example) from the opposite line side (shown collectively as the n-th line data in FIG. 4B). Is determined whether or not writing is performed on the discharge cell (that is, whether or not the discharge cell is turned on or off).

On the other hand, FIG. 5 shows a timing chart of input data and n-line driving waveforms in an even frame of the above embodiment.
As shown in FIG. 5B, the data transferred inside is all "0" (in this manner, the erase cancel data (erase cancel pulse) EC is applied to all the discharge cells of each line. As “0”, FIG.
As shown in FIG. 5D, the erase pulse EP for all the discharge cells is made valid as shown in FIG. 5C, and the data EC is not output in this manner (that is, the data EC is set as blank data). In addition, in all the discharge cells of each line, the light is turned off without generating the above-mentioned sustain discharge. As described above, in this embodiment, the frame frequency is almost doubled (for example, changed from 60 Hz to 100 Hz), and for each frame, for example, one frame of odd-numbered frames is displayed. The display is not performed as the blank data as described above, and the phenomenon of the double image is alleviated.

[0029]

According to the present invention, when the display device is driven, the display period and the non-display period are alternately set at a predetermined ratio. Is improved, and the display quality of the display device can be improved.

[Brief description of the drawings]

FIG. 1 is a panel drive timing diagram as one embodiment of the present invention.

FIG. 2 is a timing chart of driving waveforms at the time of an erasing operation for each line during the display interruption period of FIG. 1;

FIG. 3 is a timing chart of input data and internal data according to another embodiment of the present invention.

FIG. 4 is a timing chart of an input data and an n-line drive waveform in an odd frame according to another embodiment of the present invention.

FIG. 5 is a timing chart in an even-numbered frame of input data and an n-line drive waveform as another embodiment of the present invention.

FIG. 6 is a diagram illustrating a plasma display device to which the present invention is applied;

7 is a timing chart of driving waveforms at the time of writing data to each line in the device of FIG.

FIG. 8 is a panel drive timing diagram as a conventional example for the device of FIG. 6;

FIG. 9 is a panel drive timing diagram when performing gradation display for the device of FIG. 6;

FIG. 10 is a timing chart of input data and an n-line drive waveform as another conventional example.

FIG. 11 illustrates a case where panel driving according to the related art is performed.
It is a figure explaining the phenomenon of double exposure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power supply circuit 2 ... Control circuit 3 ... Vertical electrode driver 4 ... Horizontal electrode driver 5 ... Panel EP ... Narrow erase pulse WP ... Write pulse WC ... Write cancel pulse MP ... Sustain pulse

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-138691 (JP, A) JP-A-2-6992 (JP, A) JP-A-64-10297 (JP, A) JP-A-59-1984 36486 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G09G 3/28 G09G 3/288

Claims (5)

(57) [Claims] An AC plasma display having a display period for sequentially rewriting display data for display elements of each line within each frame period.
A driving method of Lee apparatus, for each frame, to set between hidden life erasing operation for all display elements sequentially the lines for each line
A method for driving an AC plasma display device, characterized in that: 2. The driving of an AC type plasma display device.
A first frame period for sequentially rewriting display data for display elements of the line for each line , and a second frame period for sequentially performing erase operations for all display elements of the line for each line to set alternately door
A method for driving an AC plasma display device, characterized in that: 3. The method according to claim 1, wherein the erasing operation for all display elements on the line is performed by applying an erasing pulse to the line and then inhibiting application of a writing pulse to the line. 4. An erasing operation for all display elements of the line is performed by first applying a write pulse to the line and then prohibiting the output of a cancel pulse to all display elements when an erasing pulse is applied. The method according to claim 1, wherein the method is performed by: 5. In each frame period, the display data for the display element of the line is sequentially rewritten for each line, and the display period for performing the sustain discharge on the rewritten display element to light the discharge cells is set. Equipment
The method for driving an AC plasma display device obtained in
Te, for each frame, without a sustain discharge in all display elements, so as to set between hidden period for turning off the display cell
A method for driving an AC plasma display device, characterized by controlling .