DE4302412A1 - Plasma display panel with hybrid AC=DC type memory - has laminated structure having strip electrodes and capacitive dielectric coupling between contact points - Google Patents

Abstract

The plasma display panel has front and rear plates (1a, 2a) separated to form a space filled with gas. A number of strip formed display electrodes (30a) are formed on one plate and scanning electrodes (10a) and common electrodes (30a) alternate on the lower plate. This has a dielectric layer (13a) under the electrodes and a further dielectric layer (14a) above. Connections (11a) are formed at the ends of the scanning electrodes. The second connection (12a) is formed as a strip. The extension of the dielectric material (131a) between the contacts provides a capacitor function. ADVANTAGE - Improved construction of hybrid AC-DC memory type screen.

Description

The invention relates to a plasma screen according to the Oberbe handle of claim 1 and a method according to the Preamble of claim 13.

The invention relates to a plasma screen and ins special a plasma screen that leads to the hybrid AC-DC memory types and an associated control.

In general, plasma screens are divided using the method used for their discharge in AC and DC types. Discharge occurs in the AC type plasma screens due to an AC control voltage in that a dielectric Layer is arranged in between. In the plasma screens of the DC type, the discharge occurs due to a DC control voltage, two opposing electrodes in the discharge space.  

Such plasma screens are also of various types divided. Plasma screens have recently been proposed at which both the response and the low Lumi nance, which is a disadvantage of these screens, have been improved. These improved plasma screens include, for example the "DC-type Pulse Memory Plasma Display Panel" (see the Japa niche published patent publication No. sho-62-211831) of the NHK Broadcasting Technology Institute of Japan as well as the "Trigger Discharge-type Plasma Display Panel "from SONY (see US patent No. 4,562,434).

The NHK plasma display uses a memory discharge function fect, so that the luminance improves by a sustained discharge sert. In this plasma screen, even after the Discharge has progressed to other lines, the discharge in one of the previous lines still at most for one "frame" (a full picture) kept upright. The NHK plasma picture shield uses space charges in the shield as storage devices and applies an impulse from the outside that starts the discharge holds and smaller than the ignition voltage and larger than the extinguishing voltage is maintained so that the discharge of the memory is maintained becomes. However, in practice it is very difficult to get one high frequency pulse that maintains the discharge to the Apply electrodes to one side of the screen; this often results malfunctions during operation. Furthermore, it is difficult to use the space charges as storage devices.

Aside from memory and easy to improve response behavior by reducing the discharge ignition time after a Signal has been applied, wall charging in the SONY plasma screen gene formed around the cathode before the actual discharge takes place. The wall charges result in an increase in voltage the voltage actually applied during discharge. This enables fast screen discharge.

In this case, since the NHK plasma screen is of the DC type the cathode material that is exposed to the discharge space,  to be bombarded with the ions that form there, verbes be reduced to reduce the damage to the cathode and thus increasing their lifespan.

Although materials that are resistant to ion bombardment, such as e.g. B. LaB ₆ in paste form, satisfactory results to extend the cathode life could not be achieved. The NHK plasma screen can also, because it is of the DC type and therefore has no memory by nature, not have the desired brightness when the so-called "line refresh" control is used.

To solve this problem, a memory is used an external circuit. However, this increases the number of discharges compared to the line scan control, and is therefore less favorable for the life of the umbrella. In addition, if the plasma screen is a color screen to be used, the mass of the discharge gas is larger and the discharge voltage is higher than in monochromatic operation, resulting in damage to the cathode.

Although the SONY plasma screen thanks to its triggered discharge shows excellent responsiveness, it is because it has no storage function compared to other plasma screens disadvantageous in order to achieve a high luminance.

Plasma is one of the known AC type plasma screens Fujitsu Ltd. screen (U.S. Patent No. 4,044,349). This The screen was constructed so that cathodes and anodes are in one simple X-Y matrix on the front and back plates are ordered. This umbrella has a complicated structure, wherein an electrode group, for control and an electrodes Unloading group, stacked on top of each other are. Since these screens are AC controlled, they continue to be their control circuits overly complicated.  

In the meantime, a plasma screen with a new structure was built by Tomson Co., Ltd. (EP Patent Publication No. 357 485 A1) beaten. The screen has a Y-electrode that is rectangular is arranged towards the data electrode (or X electrode); to this Electrodes will maintain voltage and a sense voltage applied; the screen also has an e-electrode, to which a maintenance voltage is also applied. The However, controlling the Y electrode is expensive and easy due to intense pent-up heat due to a long light emission period can be damaged.

The invention has for its object a plasma screen, of the hybrid AC-DC storage type, with an improved structure too create to selectively take advantage of a conventional DC plasma screen and an AC plasma screen.

This object is achieved by the characterizing Part of claim 1 specified features solved.

Preferred configurations result from the subclaims.

The invention provides a plasma display with memory professional structure, stable discharge and improved strength.

The invention further provides a plasma screen with memory, which is suitable for displaying colored images.

In a preferred method for controlling the plasma image umbrella according to the invention are the biases of the first and second memory pulse, which is connected to the second terminals of the Scanning electrodes and applied to the common electrode, equal, and the bias of the erase pulse that at first Connection for scanning electrodes is given the same poten tial like that of the write pulse.

In particular, the bias of the first write signal is low riger than the potential of the second write signal. Wish  the first write signal is positive and the second Write signal negative.

The following are preferred embodiments of the invention using the drawing to explain other features and before described parts of the invention. Show it:

Fig. 1 is an equivalent circuit diagram of the plasma display panel according to the invention,

Fig. 2 is a perspective view of a first exporting approximate shape of the plasma display panel, partially cut Wegge and pulled apart,

Fig. 3 is a cross-sectional view of the PDP of the invention along the line III-III in Fig. 2,

Fig. 4 is a cross-sectional view of the PDP of the invention along the line IV-IV of Fig. 2,

Figure 5 lung. A section of a second embodiment of the plasma display panel in a perspective Schnittdarstel,

Fig. 6 is a cross-sectional view of the PDP of the invention, taken along the line VI-VI in Fig. 5,

Fig. 7 shows a modification of the PDP of the invention, corresponding to FIG. 6,

Fig. 8 is a sectional view of a third embodiment accordingly Fig. 6,

Fig. 9 is a diagram of the control waveforms from a first embodiment for controlling the plasma display of the invention, and

Fig. 10 is a diagram of the control waveform from a second embodiment for controlling the plasma display of the invention.

Fig. 1 is an equivalent circuit diagram of the plasma screen showing the concept of the present invention.

Referring to FIG. 1, pairs of storage electrodes, the electrodes 10 and are made up of a common electrode 20 together, arranged in the horizontal direction parallel to each other from sample. First connections 11 and second connections 12 are located at the ends of the corresponding scanning electrodes 10 . The first connections 11 are connected to the scanning controller X and the scanning electrode 10 . The second connections 12 are connected indi rectly via capacitors 13 to the scanning electrode 10 . The common electrodes 20 are interconnected so that they are at the same potential. An antiphase rectangle change voltage is applied to the second terminals 12 of the scanning electrode 10 and to the common electrode 20 , so that the relative potential provides a periodic voltage that can maintain a discharge and which is lower than the ignition voltage of the discharge. In this case, the voltage that maintains the discharge is lower than the ignition voltage and has a potential that keeps a discharge already started going. Two write pulses, whose relative potential difference is equal to the ignition voltage of the discharge, are given by the scanning control X to the scanning electrodes 10 and by the data control Y to the display electrodes 30 . The write pulse is applied during a period in which the relative potential difference between the signals which maintain the discharge and are applied to the second connections 12 of the scanning electrodes or to the common electrode 20 is zero volts. The potential difference between the signals that maintain the discharge should be less than the ignition voltage for the discharge.

As shown in Figs. 2, 3 and 4, a front plate 1 a and a rear plate 2 are a separate so one another by a predetermined distance to form a space which is filled with gas, which is used for gas discharge . A variety of strip-shaped display electrodes 30 a are arranged parallel to each other on the inside of the front plate 1 a. On the rear plate 2 a, scanning electrodes 10 a and common electrodes 20 a are arranged alternately in the same plane between the upper dielectric layer 13 a and the lower dielectric layer 14 a. The first connections 11 a are at the end of the scanning electrodes 10 a. The second connections 12 a are, separated by the dielectric layer 13 a, under the first connections. The second connections 12 a are formed from a single piece, which extends in the direction of the arrangement of the first connections 11 a. If necessary, the second connections can also be split according to the respective scanning electrodes. A dielectric layer 13 a is located on the inner surface of the rear plate 2 a. An extended end of the dielectric layer between the first connections 11 a and the second connections 12 a takes on the role of a capacitor 131 a. In this case, the second connections 12 a can be extended to the end of the scanning electrodes 10 a as long as they do not overlap with the common electrodes 20 a. Since the overlap area of and the distance between the second connections 12 a, the first connections 11 a and / or the scanning electrodes 10 a changes the capacitance of the capacitor 131 a, the desired overlap area and the thickness of the dielectric layer 13 must be in such a structure a can be selected according to construction requirements.

The connections (not shown) of the common electrodes 20 a are located at the opposite end of the first connections 11 a and are electrically connected to one another. An upper dielectric layer 14 a is formed over the surface of the scanning electrodes 10 a and the common electrodes 20 a, the exposed upper surface of the dielectric layer 13 a between these electrodes to isolate the scanning electrodes and the common electrodes from the gas-filled space.

In a second embodiment shown in FIGS. 5 and 6, a front plate 1 b and a rear plate 2 b are separated from each other by a predetermined distance so that they form a space that is filled with gas used for gas discharge. An upper insulating layer 14 b is formed over the rear plate 2 b. Scanning electrodes 10 b, at the ends of which are the first connections 11 b, are arranged below this upper insulating layer 14 b. A lower dielectric layer 13 b is located under the scanning electrodes 10 b. The common electrodes 20 b, which lie under the scanning electrodes 10 b, and the second connections 12 b, which lie under the first connections 11 b of the scanning electrodes, are located between the lower dielectric layer 13 b and the rear plate 2 b. The second connections 12 b are formed from a single piece or body that extends in the direction of the placement of the first connections 11 b. If necessary, the second connections can also be split according to the respective scanning electrodes.

The dielectric layer 13 b is located on the inner surface of the rear plate 2 b. An extended end of the dielectric layer between the first terminals 11 b and the second terminals 12 b takes on the role of a capacitor. In this case, the second terminals can until the end of the scanning electrodes are extended 10 b, as long as the connections to the common electrodes 20 b do not overlap. Since the overlapping areas of and the distances between the second terminal 12 b, the first terminals 11 b and / or the scanning electrodes 10 b, the capacitance change, the desired area of overlap, and the thickness of the dielectric layer must requirements Konstruktionsanfor in such a structure according to selected will. The connections of the common electrodes 20 b, not shown, are located on the opposite side of the first terminals 11 b, and are electrically connected mitein other.

The second embodiment with the structure described above is characterized in that the strip-shaped common electrodes 20 b and the scanning electrodes 10 b lie in different planes. Another case could be, as shown in Fig. 8, that the scanning electrodes 10 b and the common electrodes 20 b are arranged alternately in the respective layers. The common electrodes 20 b can be arranged at right angles to the scanning electrodes 10 b and can be electrically connected together. These variations have essentially the same function as in the case that the common electrodes are arranged parallel to the scanning electrodes 10 b.

In the second embodiment of the invention, when the common electrodes 20 b and the scanning electrodes 10 b lie in different planes, the distance between the scanning electrodes 10 b can be significantly reduced, so that an image can be realized which is compared to the first Embodiment has a much higher density.

Although on the whole very similar to the second embodiment, a third embodiment, which is shown in FIG. 7, differs in that the common electrodes 20 c are formed as a single layer on the rear plate 2 b.

The following are two embodiments of a method for controlling the plasma screen of the invention which the above have structures described, explained.

The method for controlling the invention is divided into three Steps: The first step is to prepare for unloading a stand-by control step in which a gas discharge as soon as it was ignited, maintained for a certain period of time becomes. The second step is the ignition, which is a gas discharge in one of the areas that are in the stand-by step, generated. The third step is the gas discharge that is required for one was maintained for a certain period of time.

In the stand-by step, a pulsed memory signal is applied to the Given scanning electrodes and the common electrodes so that maintaining the potential between the two elec treading is carried out by a continuous discharge. In in this case the electrodes behave alternately like Katho de and anode. In the ignition step, a write pulse with the ignition voltage against the scanning electrodes and the data electrodes ben. In the step that ends the discharge, a  Pulse of the size of the ignition voltage for a very short time given duration on the data electrodes and the scanning electrodes.

As shown in FIGS. 1 and 9, in a first embodiment of a method in the stand-by step for memory discharge, a first and second memory signals A1 and B1, which accordingly have a first and second memory pulse component in each period T. a zero volt bias and a potential V _s that maintains discharge have been applied to the second terminals of all of the sensing electrodes and all of the common electrodes. The pulses A11 and B11 of the first and the second memory signal (whose bias voltage is 0 volts) are alternately applied to the second connections of the scanning electrodes and to the common electrodes for each half period T / 2, so that the scanning electrodes and the ordinary electrodes alternately behave as cathode and anode. For a time interval T, a potential is maintained for memory discharge between the scanning electrodes 10 and the common electrodes 20 , which maintains the discharge when a memory pulse is applied.

To start the discharge, during an interval in which the potential difference between the first and second memory signals A1 and A2 is zero volts, the first and second addressing signals C1 and D1 are applied to the display electrode, which is spatially separated from and at right angles to the scanning electrode and is given to the first terminal of the scanning electrode. Due to the addressing signals C1 and D1, a discharge is generated between the display electrode and the scanning electrode. In this case, since wall charges are stored in the dielectric layer 14 a or 14 b (shown in FIG. 2 or 5) that cover the scanning electrodes 10 , the discharge stops very soon and the activation particles drive into the discharge space. By mixing with the sustained voltage of the next period, the wall charges increase the level of the effective voltage that is applied to the discharge cell. This allows a discharge to be started or maintained even for a potential difference that is below the ignition voltage. In other words, when there are wall charges, and while periodic storage pulses of the first and second storage signals having a potential lower than the ignition voltage are applied to the scanning electrode and the common electrode, a discharge due to the wall charges is kept going .

The first and second addressing signals C1 and D1 have bias voltages 3V _s / 4 and V _s / 4 with different potentials, which have a relative potential difference which is below the discharge-maintaining voltage V _s . In the time interval in which the bias voltages of the control signals are applied, since the potential difference between the entire electrodes is V _s / 2 and is therefore below the ignition voltage, no discharge is generated. Under the above conditions, a discharge is not generated until the first and second write pulses C11 and D11 are applied to the display electrode 30 and to the first connection of the scanning electrode 10, whose relative potential difference is equal to that of the ignition voltage, for a certain time T _w will. In this case, since the potential difference between the first and second write pulses C11 and D11 and the first and second memory pulses A11 and B11 is below the discharge-maintaining voltage, the discharge is only generated between the scanning electrode 10 and the display electrode 30 .

If in the meantime an erase pulse during a time interval, in the storage discharge is kept going, is applied, the wall charges are extinguished to stop the discharge. An end to the discharge is achieved in that the generation of wall charges, the storage discharges under the Zünd keep tension, is suppressed. A suppression of the ore delivery of wall charges is possible by going for a very short Time generates an intense discharge, so as not to run out of time To make available in which wall charges can be generated.

In order to end a discharge, an erase pulse D12 is thus placed during a time interval in which the second memory pulse B11 is applied to the common electrode, which has a relative potential difference of the size of the ignition voltage compared to the second memory pulse B11, for a certain period of time (T _w / 10-T _w / 5) so as to suppress the generation of wall charges.

As shown in FIGS. 1 and 10, in a second embodiment of the method for providing the memory discharge, a first and a second memory signal A2 and B2 are applied to the second connection of all scanning electrodes and to the common electrodes. As a square wave signal with a bias voltage of zero volts, the first memory signal consists of a positive memory pulse component A21 with the potential V _s / 2 and a negative memory pulse component A22 with the potential -V _s / 2. The second memory signal B2, which has a negative memory pulse component B21 and a positive memory pulse component B22, has a phase difference of 180 ° with respect to the first memory signal A2, so it is, so to speak, the opposite phase to the first memory signal. Due to the first and the second memory signal, the relative potential difference between the scanning electrode 10 and the common electrode 20 is lower than the discharge ignition voltage.

To start the discharge, during a time interval in which the potential difference between the first and second memory signals A2 and B2 is zero volts, the first and second addressing signals C2 and D2 on the display electrode 30 , which are spatially separated from and is perpendicular to the scanning electrode 10 , and given at its first terminal. The first and second addressing signals C2 and D2 have bias voltages of V _s / 4 and -V _s / 4, which are continuously applied to the first terminal 11 of the scanning electrode 10 and the display electrode 30, respectively, and a potential difference which is below the discharge-maintaining voltage , exhibit. The first and second addressing signals also have first and second write pulses C21 and D21, the relative potential difference of which is above the ignition voltage and each of which has a relative potential difference of the first and second memory pulses A21 and B21 which is below the discharge sustain voltage.

To terminate the discharge, during a time interval in which the first and second memory pulses A21 and B21 are applied to the second terminal 12 of the scanning electrode and to the common electrode 20 , an erase pulse D22 which is relative to the second memory pulse B21 Potential difference, which is below the ignition voltage, briefly given to the first terminal 11 of the scanning electrode 10 for a certain time T _w in order to suppress the formation of wall charges.

In the control method according to the invention, the Biases of the first and second memory pulses applied to the second connection of the scanning electrode and to the common elec trode be created, the same. The potential of the bias of the Erase pulse on the first terminal of the scanning electrode is given is the same as that of the write pulse. Ins special is the potential of the bias of the first write pulse lower than that of the second write pulse. The first Write pulse is positive and the second write pulse is nega tiv.

In the plasma screen of the invention, as described above has an AC memory discharge structure in which a scan electrode and a common electrode between which the Discharge can be maintained for a long time protected by a dielectric layer in contrast to DC discharge structures no difficulty the selection of the electrode material. As a procedure for addressing The discharge mainly uses a DC Discharge process, so the circuit structure of the control unit to simplify and to quickly generate a discharge in the Contrary to the AC discharge process, which delays the discharge device. The present invention has an AC-DC hybrid type structure that shows the advantages of DC and AC plasma screens exploits. Furthermore, the plasma screen of the invention has thanks  its stable AC storage discharge a faster response behave and have an extended lifespan. The invention is for Color screens much more suitable than for monochromatic ones Screens.

A plasma screen consists of a front and rear plate 1 a and 2 a or 1 b and 2 b, which form a discharge space, from display electrodes 30 a, which are arranged on the front plate and from strip-shaped scanning electrodes 10 a and 10 b. These scanning electrodes do not come into contact with the gas due to a dielectric layer 14 a or 14 b with which they are coated. These electrodes have first terminals 11 a and 11 b, which are electrically connected at their ends, and second terminals 12 a and 12 b, which are indirectly connected to them by an intermediate capacitor layer 131 a made of dielectric material. A common electrode 20 a and 20 b is arranged together with the first connections and the capacitively coupled by a dielectric layer second connections of the scanning electrodes on the rear plate. A large number of barriers are located between the front and rear panels. The plasma screen has an AC-DC hybrid discharge structure, which takes advantage of a DC plasma screen and an AC plasma screen.

Claims (14)

1. plasma screen,
characterized,
that a front and rear plate ( 1 a and 2 a or 1 b and 2 b) are provided, which are separated by a predetermined distance to form a discharge space which is filled with a discharge gas,
that a plurality of parallel display electrodes ( 30 a), which point in a first direction, are attached to the inner upper surface of the front plate,
that a plurality of strip-shaped scanning electrodes ( 10 a and 10 b) on the rear plate pointing in a second direction, which is perpendicular to the first, are arranged, the scanning electrodes due to a dielectric layer ( 14 a and 14 b), with of which they are coated, do not come into contact with the gas in the discharge space and these scanning electrodes have first connections ( 11 a and 11 b) which are electrically connected to one end of the scanning electrodes, and second connections ( 12 a and 12 b) which are indirectly connected by an intermediate capacitor layer ( 131 a) made of dielectric material,
that a common electrode ( 20 a or 20 b), which is angeord net on the rear plate together with the first connections, and is capacitively coupled to these by means of a dielectric layer,
that a plurality of barriers parallel to the first connections are provided between the front and rear plate. 2. Plasma screen according to claim 1, characterized in that the common electrode is formed as a single layer under the scanning electrodes and a dielectric layer ( 13 b) lies between the two electrodes, so that a sandwich structure is formed. 3. Plasma screen according to claim 1, characterized in that the common electrode is split into a plurality of strip-shaped elements, all of which are electrically connected to one another, and these split elements are separated by a dielectric layer ( 13 a) under the scanning electrodes . 4. Plasma screen according to claim 3, characterized, that each of these split elements of the common Electrode parallel and alternating with the scanning electrodes is arranged on the same level, and that the dielectri cal layer on the scanning electrodes, the split Elements of the common electrode and in between  lies, so that in this way an alternating discharge structure is formed. 5. Plasma screen according to claim 1, characterized, that the common electrode through an insulating layer is arranged separately under the scanning electrodes. 6. Plasma screen according to claim 5, characterized, that the common electrode is formed as a single layer det. 7. plasma display according to claim 5, characterized, that strip the common electrode into a variety of shaped, parallel elements, all of which are electrically connected are connected, is split. 8. plasma screen according to claim 7, characterized, that the strip-shaped elements of the common electrode are arranged parallel to the scanning electrodes. 9. plasma display according to claim 8, characterized, that each of the strip-shaped elements of the common Electrode each scanning electrode by a certain distance transferred. 10. Plasma screen according to claim 7, characterized, that the striped elements of the common electrode are perpendicular to the scanning electrodes. 11. Plasma screen according to at least one of claims 1 to 10,  characterized, that the first and second ports face each other are arranged horizontally, with a dielek between the two trical layer, so that a capacitor is formed. 12. Plasma display according to claim 11, characterized, that the second connections in the direction of the first to conclusions are formed as one body. 13. A method for controlling a plasma screen according to claim 1, characterized in that

• a) to provide or for the stand-by operation of the storage discharge, a first and a second storage signal, the periodic first and second storage pulse components with a bias of zero volts and a potential that allows continuous discharge to the second connections the scanning electrode is applied to or on the common electrode, and the pulses of the first and second memory signals are applied alternately to the second connections of the scanning electrode and to the common electrode,
  the pulses of the first and second memory signals are alternately applied to the second terminals of the scanning electrode and the common electrode so as to secure a discharge sustain voltage difference between the scanning electrodes and the common electrode for the memory discharge for a certain period of time,
• b) to start the discharge, a first and second addressing signal to the display electrodes which maintain a predetermined distance from and perpendicular to the scanning electrodes, and to the second connections of the scanning electrodes who the if the potential difference between the first and second Memory signals is zero volts,
  the first and second addressing signals have bias voltages with different potential, the potential difference being below the discharge maintenance voltage and containing first and second write pulses with a predetermined period, the relative potential difference of which is above a discharge ignition voltage and which has a potential difference to the first and second memory pulses have which is below the discharge maintenance voltage,
• c) to end the discharge during an interval during which the second storage pulse is applied to the common electrode, a pulse is applied across the first terminals of the scanning electrodes, which has a potential difference compared to the second storage pulse, which is above the discharge ignition voltage.

14. A method for controlling a plasma screen according to claim 1, characterized in that

• a) for the stand-by operation of the storage discharge, a first and second storage signal is applied to all the second connections of the scanning electrode and the common electrode,
  the first memory signal is a square wave or an alternating square wave signal with a bias potential of zero volts and a positive memory pulse component and a negative memory pulse component having the same potential, the second memory signal is the opposite phase signal to the first memory signal, so that the relative Po potential difference between the scanning electrodes and the common electrode is a discharge maintenance value which is below a discharge ignition voltage,
• b) for starting the discharge, first and second addressing signals to the display electrodes, which are spaced apart from the scanning electrodes by a predetermined distance and are perpendicular to them, and to the second connections of the scanning electrodes when the potential difference between the first and second is applied Memory signal is zero volts,
  the first and second addressing signals have bias voltages with different potentials, which have a potential difference below the discharge maintenance voltage and first and second write pulses with a predetermined period, whose relative potential difference lies above the discharge ignition voltage and have a potential difference with respect to the first and second memory pulses sen, which is below the discharge maintenance voltage,
• c) to terminate the discharge during an interval during which the first and second storage pulses are applied to the second connections of the scanning electrodes and the common electrode, an erase pulse is applied across the first connections of the scanning electrodes, which has a potential difference compared to the second storage pulse , which is above the discharge ignition voltage.