JPH05297821A - Interlaced driving method for plasma address picture display device - Google Patents

Abstract

PURPOSE:To enable driving a plasma address piecture display device by interlaced scanning in line sequentiality. CONSTITUTION:When a plasma address picture display device in which a picture signal is applied to an electro-optial material layer positioned at the crossing section of signal electrodes D1, D2, D3...Dm and a discharge plasma region with the scanning unit of the discharge plasma region consisting of pairs of cathodes K1, K2, K3...Kn and corresponding anodes A1, A2, A3...An is driven by interlaced scanning, the discharging plasma region is successively scanned with a period of 1/2 period H of a horizontal synchronizing signal HD while being synchronized with a vertical synchronizing signal and a piecture signal D is switched with the period H of the horizontal synchronizing signal H while being synchronized with a pulse of the horizontal synchronizing signal HD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma addressed image display device having a two-layer structure of a display cell such as a liquid crystal cell and an addressing plasma cell. More specifically, it relates to an interlace drive system of a plasma addressed image display device.

[0002]

2. Description of the Related Art Conventionally, a CRT is most commonly used for displaying moving images on a television or the like. However, the CRT has a drawback that it is difficult to make the device thin because it uses a cathode tube. In recent years, a wide variety of image display devices having a flat panel structure, which replaces the CRT, have been developed. Among them, as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-217396, a plasma addressed image display device having a flat panel structure in which an image display cell and a plasma cell for switching are superposed is in the research and development process.

As shown in FIG. 4, the plasma addressed image display device has a laminated structure including, for example, a liquid crystal cell 101, a plasma cell 102 and an intermediate plate 103 interposed therebetween. The plasma cell 102 is formed using a glass substrate 104, and has a plurality of parallel grooves 10 formed on its surface.
5 are provided. The groove 105 extends, for example, in the row direction of the matrix. Each groove 105 is an intermediate plate 103
Separately separated plasma chamber 10 sealed by
6 is composed. An ionizable gas is enclosed in the closed plasma chamber 106. Adjacent groove 1
The convex portion 107 separating 05 serves as a partition wall for partitioning the individual plasma chambers 106, and
Also plays a role as a gap spacer. Each groove 1
A pair of plasma electrodes 10 parallel to each other is provided on the bottom of 05.
8,109 are provided. A pair of electrodes is anode A
And functions as a cathode K to ionize the gas in the plasma chamber 106 and generate discharge plasma. The discharge area is a row scanning unit.

On the other hand, the liquid crystal cell 101 is composed of a transparent substrate 110. The transparent substrate 110 is the intermediate plate 10.
3 are opposed to each other through a predetermined gap, and a liquid crystal layer 111 is filled in the gap. A signal electrode D made of a transparent conductive material is formed on the inner surface of the transparent substrate 110. The signal electrode D is orthogonal to the plasma chamber 106 and serves as a column driving unit. Matrix-shaped pixels are defined at the intersections of the column driving units and the row scanning units.

In the image display device having such a structure, the plasma chamber 106 in which plasma discharge is performed is switched and scanned, and a drive signal is applied to the signal electrode D on the liquid crystal cell side in synchronization with this scan to drive the display. Is performed. When plasma discharge is generated in the plasma chamber 106, the anode potential becomes substantially uniform inside, and pixel selection is performed for each row. That is, the plasma chamber 106 functions as a sampling switch. When a driving signal is applied to each pixel while the plasma sampling switch is in a conductive state, sampling and holding is performed and lighting or extinction of the pixel can be controlled. The drive signal is retained in the pixel as it is even after the plasma sampling switch is turned off. Therefore, this image display device has a memory function.

[0006]

One screen of a moving image display television, that is, one frame is composed of 525 horizontal lines. When one-screen display is performed using a CRT, the fluorescent surface is scanned with 525 electron beams. There are a non-interlace method and an interlace method in this scanning method. For simplicity, the case of 10 lines is shown as an example in FIG. FIG. 5A shows a non-interlaced system in which 525 lines are scanned line-sequentially at one time.

On the other hand, FIGS. 5B and 5C show the interlace system. One frame is divided into two fields (B) and (C) and interlaced scanning is performed every other line, and both are combined to form one frame. In a television image, 525 scans are repeated 30 times per second in order to suppress flicker and respond to fast movement. In the interlace method, the odd field and the even field are each repeated 30 times per second. Therefore, the total number of repetitions is 60 times. The interlaced method has an advantage that flicker on the screen of the eyes is reduced as compared with the non-interlaced method.

As is clear from the above description, it is preferable that the plasma addressed image display device also be driven by the interlace system. In this case, two driving methods can be considered. FIG. 6A shows the first driving method. C
Similar to RT, this is a method of scanning different lines in the odd field and the even field every other line. Each line corresponds to an individual discharge area. This first method is the most ideal from the viewpoint of resolution, but since the plasma address image display device has a memory function as described above, when moving images are displayed, the image in the previous field is temporarily Since it is held and displayed at the same time, it is not preferable because it is observed as an afterimage.

FIG. 6B shows a second driving method. This is a method of scanning two lines each having different combinations in the odd field and the even field. This second
With this method, a display image that is the most natural and close to a CRT can be obtained. However, since the plasma discharges corresponding to the two lines are simultaneously performed, there are the following problems. Generally, when performing plasma discharge, a discharge current is supplied to each line through a common load resistor. However, the plasma electrodes forming each line have variations in shape, electric resistance and the like. Therefore, when two lines are scanned at the same time, discharge concentrates on one side and uniform plasma cannot be obtained, which may impair the image quality. In addition, there is a problem in that an additional circuit is required to select a pair of lines at the same time, which complicates the drive circuit configuration.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned problems or problems of the prior art, an object of the present invention is to perform complete interlaced driving of a plasma addressed image display device with a simple circuit configuration. The following measures have been taken in order to achieve this object. That is, in the driving method of the plasma addressed image display device, wherein the image signal is applied to the electro-optical material layer located at the intersection of the signal electrode and the discharge plasma region with the discharge plasma region as a scanning unit, A means for scanning at a period of ½ of the period of the horizontal synchronizing signal and in synchronization with the vertical synchronizing signal, and switching the image signal at the period of the horizontal synchronizing signal and in synchronization with the pulse of the horizontal synchronizing signal is provided. I took it.
The plasma addressed image display device includes a first substrate having a plurality of signal electrodes arranged parallel to each other along a predetermined main surface and a plurality of plasmas arranged orthogonal to the signal electrodes and parallel to each other. A second electrode having an electrode and arranged so that the plasma electrode faces the signal electrode.
Substrate, an electro-optical material layer inserted between the first and second substrates, and a plasma chamber for enclosing the ionizable gas formed between the electro-optical material layer and the second substrate. ing. The gas is selectively ionized by the discharge between the adjacent plasma electrodes, and an image signal is applied to the electro-optic material layer located at the intersection of the signal electrode and the discharge region with the discharge region where the ionized gas is localized as a scanning unit. Then, it is displayed.

[0011]

According to the present invention, the plasma discharge is performed line by line for each scanning unit, that is, for each line. At this time, each line is sequentially scanned in synchronization with the vertical synchronizing signal at a cycle of 1/2 of the horizontal synchronizing signal. In other words, scanning is performed sequentially at twice the frequency of the horizontal synchronizing signal. On the other hand, the switching of the image signal applied to the signal electrode group is performed in the cycle of the horizontal synchronizing signal and in synchronization with the pulse of the horizontal synchronizing signal. In other words, the switching of the image signal is performed for each unit at the frequency of the horizontal synchronizing signal. Therefore, one line of image signal is assigned to two lines. In this way, the effect of discharging two lines at the same time is equivalently obtained even if the discharge is actually performed one line at a time. Moreover, since the common load resistance always limits the discharge current of only one line, it is possible to avoid the drawback that current concentration occurs in one line as in the case of discharging two lines at the same time.

Since the plasma discharge for each line is performed at a rate twice the frequency of the horizontal synchronizing signal, the scanning is repeated twice per frame. In the odd field and the even field, the line pairs are shifted one by one, so that the interlace drive can be automatically realized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram for explaining a driving method of a plasma addressed image display device according to the present invention. 1A shows a circuit configuration, and FIG. 1B is an operation waveform diagram. The apparatus is composed of a drive circuit 1, a scanning circuit 2 and a control circuit 3. The drive circuit 1 has a signal electrode D1.
Through Dm are connected via a buffer. on the other hand,
The scanning circuit 2 also has a cathode electrode K via a buffer.
1 to Kn are connected. The anode electrodes A1 to An are arranged in the vicinity of the corresponding cathode electrodes K1 to Kn to form a discharge region for each scanning unit, and are commonly grounded to each other. A constant voltage power supply E is inserted between a common grounded anode electrode and each cathode electrode via a common load resistor R. Each cathode electrode K1
The selection of Kn through Kn is performed by the scanning circuit 2. In this embodiment, only the cathode electrode is selectively driven, but the invention is not limited to this. For example, a method of dividing and multiplexing the anode electrode may be adopted.

As described above, the cathode electrode is line-sequentially scanned by the scanning circuit 2. The scanning speed in this case is set to twice the frequency f _H of the horizontal synchronizing signal H _D , that is, 2f _H. On the other hand, the drive circuit 1 supplies the image signal to the signal electrode group in synchronization with the frequency f _H of the horizontal synchronizing signal H _D. Switching of the image signal is performed in synchronization in other words the horizontal synchronizing signal H _D. The control circuit 3 controls the drive circuit 1 and the scanning circuit 2 synchronously. As described above, the plasma discharge region is formed along each cathode electrode to form a row scanning unit.
On the other hand, each signal electrode serves as a column driving unit. A pixel is defined between both units.

Next, the operation of the circuit shown in FIG. 1A will be described in detail with reference to FIG. Cathode electrode K1,
K2, K3 ... Are line-sequentially selected at a frequency 2f _H which is twice the frequency of the horizontal synchronizing signal H _D. Therefore, on-time hit allocated to each cathode electrode is equal to 1/2 of the period H of the horizontal synchronizing signal H _D. When 525 line-sequential scanning is performed, the vertical synchronizing signal V _D resets and the first field ends. Subsequently, similar line sequential scanning is repeated in the second field. By repeating this twice, 1
The frame is constructed. In order to perform such line sequential scanning, for example, the scanning circuit 2 is reset to V _D and
A shift register that shifts at f _H may be used.

[0016] On the other hand the image signal D is sequentially switched in synchronism with the horizontal synchronizing signal H _D. Therefore, one unit of the image signal has a length equal to the period H of the horizontal synchronizing signal H _D and includes 525 units per frame. In order to perform such switching of image signals, the drive circuit 1 may sequentially perform sampling hold output with a clock synchronized with _HD , for example. If the external input signal supplied to the drive circuit 1 is in the interlace format, the first field and the second field are automatically deviated by half the horizontal period H with respect to the timing of the vertical synchronizing signal V _D. ..

In the plasma addressed image display device, the voltage applied to the pixel is the image signal at the end of plasma discharge. For example, in the odd field, the same voltage is written in a pair of lines corresponding to the cathode electrodes K1 and K2. In an even field, the same voltage is written in a pair of lines corresponding to the cathode electrodes K2 and K3, for example. In this way, the same effect as in the case of discharging two lines at the same time is equivalently obtained even if the discharge is performed for each line. Moreover, since the common load resistance R always limits the discharge current of only one line, it is possible to avoid the drawback that the discharge concentrates on one line as in the case of simultaneously discharging two lines. Further, in the odd field and the even field, the correspondence relationship between the pair of cathode electrodes and each unit of the image signal D is shifted by one line. That is,
In the odd field, pairs are formed like K1 and K2, K3 and K4, while in the even field, K2 and K2.
Pairs are constructed like 3, K4 and K5. Therefore, complete interlace drive is performed.

FIG. 2 is a schematic diagram showing the plasma addressed image display device shown in FIG. 1 with a few pixels cut out.
Each pixel 4 has a corresponding one of the signal electrodes D1 and D2 forming a column driving unit.
Is located at the intersection of row scanning units and constitutes a sampling capacitor. Plasma sampling switches S1, S2, S3 ... Are connected in series to each sampling capacitor. The plasma sampling switch is an equivalent expression of the function of the discharge region. That is, when the discharge region is activated, the inside thereof is almost entirely connected to the anode potential. On the other hand, when the plasma discharge ends, the discharge region becomes a floating potential. An image signal is written to a sampling capacitor that constitutes each pixel 4 via a sampling switch, and so-called sampling and holding is performed.

Finally, an example of a plasma addressed image display device driven by the method of the present invention will be described with reference to FIG. Unlike the conventional example shown in FIG. 4, in this example, the plasma electrode is formed on a flat substrate surface, which is suitable for displaying a large moving image. This device includes a liquid crystal cell 11 and a plasma cell 12.
And an intermediate plate 13 interposed between the two. The liquid crystal cell 11 has a first substrate, for example, a glass substrate 14
, And a plurality of first electrodes made of a transparent conductive film, that is, signal electrodes D are formed in parallel with each other on the inner main surface thereof. The substrate 14 is adhered to the intermediate plate 13 using a spacer 15 with a predetermined gap. A liquid crystal layer 16 which is an electro-optical material layer is filled in the gap.
In this embodiment, a fluid electro-optical material is used, but the material is not limited to this. For example, an electro-optic crystal plate can be used. In this case, the intermediate plate 1
It is also possible to remove 3.

On the other hand, the plasma cell 12 is constructed by using a second substrate such as a glass substrate 17. A second electrode, that is, a plasma electrode 18 orthogonal to the signal electrode D is formed on the inner main surface of the substrate 17. The plasma electrode 18 includes an anode electrode A and a cathode electrode K, which form a pair. A partition 19 is provided so as to separate each pair. The substrate 17 is bonded to the intermediate plate 13 by using a sealing material 20. An airtightly sealed plasma chamber 21 is formed between the two. The plasma chamber 21 is divided by the partition wall 19 and individually constitutes a discharge region 22 which is a row scanning unit. An ionizable gas is enclosed in the airtight plasma chamber 21. The gas species can be selected from, for example, helium, neon, argon or a mixed gas thereof.

[0021]

As described above, according to the present invention, an image signal is applied to the electro-optical material layer located at the intersection of the signal electrode and the discharge plasma region with the discharge plasma region as a scanning unit. In the plasma addressed image display device, the discharge plasma region is synchronized with the vertical synchronizing signal and sequentially scanned at a speed twice the frequency of the horizontal synchronizing signal, and the switching of the image signal is performed at the frequency of the horizontal synchronizing signal and the horizontal synchronizing signal. Complete interlace drive is realized by synchronizing with the pulse of. There is an effect that interlace driving can be performed without adding a special circuit with a simple circuit configuration that simply doubles the line-sequential scanning of the discharge plasma region. In addition, the drive circuit according to the present invention has an effect that the non-interlace operation can be executed as it is when the non-interlace signal is input.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a driving method of a plasma addressed image display device according to the present invention.

FIG. 2 is a schematic view showing a pixel of a plasma addressed image display device by cutting out a pixel.

FIG. 3 is a structural diagram showing an example of a plasma addressed image display device to which the present invention is applied.

FIG. 4 is a schematic perspective view showing an example of a conventional plasma addressed image display device.

FIG. 5 is a schematic diagram for explaining an interlace drive system.

FIG. 6 is a schematic diagram for explaining the interlaced driving method.

[Explanation of symbols]

 1 Driving Circuit 2 Scanning Circuit 3 Control Circuit A Anode K Cathode D Signal Electrode R Load Resistance

Claims (2)

[Claims] 1. A driving method of a plasma addressed image display device, wherein an image signal is applied to a signal electrode and an electro-optic material layer located at an intersection of the discharge plasma region with a discharge plasma region as a scanning unit. The plasma region is sequentially scanned in a cycle of 1/2 of the horizontal synchronizing signal and in synchronization with the vertical synchronizing signal, and the switching of the image signal is performed in the period of the horizontal synchronizing signal and in synchronization with the pulse of the horizontal synchronizing signal. An interlace driving method for a plasma addressed image display device characterized by being carried out. 2. A first substrate having a plurality of first electrodes arranged parallel to each other along a predetermined main surface, and a plurality of second electrodes orthogonal to the first electrodes and arranged parallel to each other. And a second substrate having the second electrode arranged so as to face the first electrode, an electro-optical material layer interposed between the first and second substrates, and the electro-optical material. A plasma chamber for enclosing an ionizable gas formed between a layer and the second substrate is provided, and the gas is selectively ionized by discharge between adjacent second electrodes, and the ionized gas is localized. The first discharge area is used as a scanning unit.
In a plasma addressed image display device in which an image signal is applied to an electro-optic material layer located at the intersection of an electrode and the discharge region, the discharge region is provided with a period of 1/2 of a period of a horizontal synchronization signal and a vertical synchronization. A plasma addressed image display device comprising interlace operation means for sequentially scanning in synchronism with signals and switching the image signals at a cycle of a horizontal synchronizing signal and in synchronism with a pulse of the horizontal synchronizing signal.