JP3326812B2 - Interlace driving method for plasma addressed image 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 plasma addressed image display device having a two-layer structure of a display cell such as a liquid crystal cell and an address plasma cell. More specifically, the present invention relates to an interlace driving method for a plasma addressed image display device.

[0002]

2. Description of the Related Art Conventionally, a CRT is most commonly used for displaying a moving image such as a television. However, the CRT has a disadvantage that it is difficult to reduce the thickness of the device because a cathode ray tube is used. 2. Description of the Related Art In recent years, various types of image display devices having a flat panel structure replacing CRTs 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 switching plasma cell are overlapped is in the research and development process.

As shown in FIG. 4, the plasma addressed image display device has a laminated structure composed of, 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 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
Plasma chamber 10 sealed by
6. The sealed plasma chamber 106 is filled with an ionizable gas. Adjacent groove 1
The convex portion 107 separating the plasma chambers 05 serves as a partition for separating the individual plasma chambers 106 and the plasma chambers 106.
Also serves as a gap spacer. Each groove 1
05, a pair of parallel plasma electrodes 10
8, 109 are provided. A pair of electrodes are anode A
And functions as a cathode K to ionize gas in the plasma chamber 106 to generate discharge plasma. Such a discharge region is a unit of row scanning.

On the other hand, the liquid crystal cell 101 is configured using a transparent substrate 110. This transparent substrate 110 is used for the intermediate plate 10.
The liquid crystal layer 111 is filled with a liquid crystal layer 111 in a position opposite to the liquid crystal layer 3 with a predetermined gap therebetween. Further, 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 drive unit. A matrix of pixels is defined at the intersection of the column drive unit and the row scan unit.

[0005] In the image display apparatus having the above-described structure, the display chamber is switched by switching the plasma chamber 106 in which plasma discharge is performed and applying a drive signal to the signal electrode D on the liquid crystal cell side in synchronization with the scan. Is performed. When a plasma discharge is generated in the plasma chamber 106, the inside thereof becomes substantially uniformly at the anode potential, and pixel selection for each row is performed. 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 turned on, sampling and holding are performed, and lighting or extinguishing of the pixel can be controlled. The drive signal is held 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, that is, one frame, of the moving image display television is constituted by 525 horizontal lines. When one screen is displayed by using a CRT, 525 electron beams are scanned on the fluorescent screen. This scanning method includes a non-interlace method and an interlace method. For simplicity, FIG. 5 shows a case of ten lines as an example. FIG. 5A shows a non-interlaced system in which 525 lines are scanned line-sequentially at a time.

On the other hand, FIGS. 5B and 5C show an interlace system. One frame is divided into two fields (B) and (C), and interlaced scanning is performed every other line to constitute one frame. In a television image, 525 scans are repeated 30 times per second 30 times 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 interlace method has an advantage that flicker on an eye screen is reduced as compared with the non-interlace method.

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

FIG. 6B shows a second driving method. This is a method of scanning two lines each having a different combination in an odd field and an even field. This second
The method of (1) can obtain a display image most natural and close to a CRT. However, since the plasma discharges corresponding to the two lines are performed simultaneously, there is the following problem. Generally, when performing a plasma discharge, a discharge current is supplied to each line via a common load resistor. However, there are variations in the shape, electric resistance, and the like of the plasma electrodes constituting each line. Therefore, when two lines are scanned at the same time, discharge is concentrated on one of the lines and uniform plasma cannot be obtained, which may deteriorate image quality. In addition, there is a problem that an additional circuit is required to select a pair of lines at the same time and the driving circuit configuration is complicated.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned problems or problems of the prior art, it is an object of the present invention to perform complete interlace driving of a plasma addressed image display apparatus with a simple circuit configuration. The following measures were taken to achieve this purpose. That is, the odd field and the even field are formed in 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 method of driving a plasma addressed image display device in which an image signal of an interlace format divided into two groups is applied, the discharge plasma region is set at a period of half a period of a horizontal synchronization signal and in synchronization with a vertical synchronization signal. In addition to the scanning, the switching of the image signal is performed at the cycle of the horizontal synchronization signal and in synchronization with the pulse of the horizontal synchronization signal. Therefore, two lines scanned continuously
Image signals of the same voltage for a set of discharge plasma regions
Allocate and odd and even fields
And two lines of discharge plasma to which the same voltage is assigned
The feature is that the set of mask areas is shifted by one line
I do. Note that 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 plasma electrodes arranged orthogonal to the signal electrodes and parallel to each other. A second substrate having an electrode and the plasma electrode disposed so as to face the signal electrode; an electro-optic material layer inserted between the first and second substrates; A plasma chamber for sealing an ionizable gas formed between the two substrates is provided. 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 using the discharge region where the ionized gas is localized as a scanning unit. Display.

[0011]

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

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

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail 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. FIG. 1A shows a circuit configuration, and FIG. 1B is an operation waveform diagram. This device comprises a driving circuit 1, a scanning circuit 2, and a control circuit 3. The drive circuit 1 has a signal electrode D1
To 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, respectively, constitute 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
Or Kn is selected by the scanning circuit 2. In this embodiment, only the cathode electrode is selectively driven, but the present invention is not limited to this. For example, a method of dividing and multiplexing the anode electrode may be adopted.

As described above, the scanning circuit 2 scans the cathode electrode line-sequentially. Scan speed in this case is set to be twice i.e. 2f _H of the frequency f _H of the horizontal synchronizing signal H _D. Meanwhile the driving circuit 1 supplies the image signal to the signal electrodes in synchronism 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 synchronization between the drive circuit 1 and the scanning circuit 2. As described above, a plasma discharge region is formed along each cathode electrode, and becomes a unit of row scanning.
On the other hand, each signal electrode is a column drive unit. Pixels are 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 twice 2f _H of 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. 525 line sequential to scan the the first field are reset by the vertical synchronizing signal V _D is completed. Subsequently, the same line sequential scanning is repeated in the second field. By repeating twice like this, 1
A frame is configured. In order to perform such a line sequential scanning, for example, the scanning circuit 2 is reset by V _D and 2
may be a shift register which shifts at f _H.

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

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

FIG. 2 is a schematic diagram showing several pixels of the plasma addressed image display device shown in FIG. 1 cut out.
Each pixel 4 is connected to each of the signal electrodes D1, D2 constituting a column drive unit.
.. And a sampling capacitor. Plasma sampling switches S1, S2, S3,... Are connected in series to each sampling capacitor. The plasma sampling switch equivalently represents the function of the discharge region. That is, when the discharge region is activated, the inside of the discharge region 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 into a sampling capacitor constituting each pixel 4 via a sampling switch to perform a so-called sampling hold.

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 large-size moving image display. This device comprises a liquid crystal cell 11 and a plasma cell 12
And an intermediate plate 13 interposed therebetween. The liquid crystal cell 11 is a first substrate such as a glass substrate 14
A plurality of first electrodes, ie, signal electrodes D, made of a transparent conductive film are formed in parallel on the inner main surface. The substrate 14 is bonded to the intermediate plate 13 with a predetermined gap using a spacer 15. The gap is filled with a liquid crystal layer 16 which is an electro-optical material layer.
In the present embodiment, a fluid electro-optic material is used, but it is not necessarily 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 constituted by using a second substrate, for example, a glass substrate 17. On the inner main surface of the substrate 17, a second electrode, that is, a plasma electrode 18 orthogonal to the signal electrode D is formed. The plasma electrode 18 includes an anode electrode A and a cathode electrode K, and makes a pair. A partition wall 19 is provided so as to separate each pair. The substrate 17 is bonded to the intermediate plate 13 using a sealing material 20. An airtightly sealed plasma chamber 21 is formed between the two. The plasma chamber 21 is divided by a partition wall 19 and individually constitutes a discharge region 22 serving as a row scanning unit. An ionizable gas is sealed in the airtight plasma chamber 21. The gas type can be selected from, for example, helium, neon, argon, or a mixed gas thereof.

[0021]

As described above, according to the present invention, 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. In the plasma addressed image display device, the discharge plasma region is sequentially scanned at a speed twice as high as the frequency of the horizontal synchronization signal in synchronization with the vertical synchronization signal, and the switching of the image signal is performed at the frequency of the horizontal synchronization signal and the horizontal synchronization signal. A complete interlace drive is realized by performing the operation in synchronization with the pulse. With a simple circuit configuration that simply doubles the line sequential scanning speed of the discharge plasma region, there is an effect that the interlace drive can be performed without adding a special circuit. 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 the drawings]

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

FIG. 2 is a schematic diagram showing a cut-out pixel of a plasma addressed image display device.

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 driving method.

FIG. 6 is a schematic diagram for explaining an interlace driving method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive circuit 2 Scanning circuit 3 Control circuit A Anode K Cathode D Signal electrode R Load resistance

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H04N 5/66 101 G09G 3/28 H (58) Fields investigated (Int.Cl. ⁷ , DB name) G09G 3/20 622 G09G 3/20 650 G02F 1/133 505 G09G 3/28 G09G 3/36 H04N 5/66 101

Claims (2)

(57) [Claims] 1. An odd field and an even field in an electro-optic material layer located at an intersection of a signal electrode and the discharge plasma region with a discharge plasma region as a scanning unit .
In a driving method of a plasma addressed image display device in which an image signal of an interlace format is applied, the discharge plasma region is sequentially scanned in a cycle of a half of a cycle of a horizontal synchronization signal and in synchronization with a vertical synchronization signal. the image signal switching rows stomach and in synchronism with the pulses of the horizontal synchronizing signal in a cycle of the horizontal synchronizing signal, I following, two lines discharge plasma region that is followed by scanning
Image signals of the same voltage
The same voltage is divided between the odd and even fields.
A set of two lines of discharge plasma area to be applied is one line
An interlaced driving method for a plasma addressed image display device, characterized in that the interlaced driving method is shifted . 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. A second substrate having a second electrode disposed so as to face the first electrode, an electro-optic material layer interposed between the first and second substrates, A plasma chamber for enclosing an ionizable gas formed between the layer and the second substrate, wherein the gas is selectively ionized by discharge between adjacent second electrodes, and the ionized gas is localized; The first discharge area as a scanning unit with
In the electro-optic material layer located at the intersection of the electrode and the discharge region, an interface divided into an odd field and an even field is provided.
A plasma address image display device adapted to apply a race format image signal, wherein: a scanning circuit for sequentially scanning the discharge region at a period of half a period of a horizontal synchronization signal and in synchronization with a vertical synchronization signal; Bei a driving circuit for performing switching of the image signal in synchronism with the pulses of the horizontal synchronizing signal period in and horizontal synchronizing signals
In addition, the driving circuit includes a discharge area of two lines continuously scanned.
Image signals of the same voltage
The same voltage is divided between the odd and even fields.
Shift the set of two applied discharge areas by one line
Plasma address image display device according to claim that it has to Suyo.