DE2310275C3 - Control circuit for a display device - Google Patents

Description

The invention relates to a control circuit for a display device using a Gas discharge space and first and second sets of electrodes.

A display device has dielectric Layers covered electrodes opposite one another with a gas discharge space delimited between them and a charge generated by a discharge is placed in the dielectric layers stored to provide both a memory function and a display function. The one in the dielectric Layer of stored charge, d. H. the so-called wall charge, has hitherto been considered to be attenuated in the order of milliseconds and not stored for hours or days like a charge storage tube. To e.g. a To reproduce wall charge patterns before it is erased, it is necessary to maintain an alternating voltage of at least about 1 kHz, and since the repetition frequency of the maintenance voltage is decreased, the memory content becomes smaller. It has been assumed that this is due to the fact originates from the fact that the wall tension due to the sheet resistance of the dielectric layer or the like. leaks and scatters into the gas discharge space at the intervals of discharge

In this known control circuit occurs, for. B. a Compensation process depending on the time constants of the voltage sources of the maintenance voltage and a togic circuit at the time of turning off and turning on the voltage sources, thereby causing the plasma display panel works as if it were an erase pulse with a low voltage or narrow pulse width is created. Furthermore, there is a static tendency that ignition occurs at the time of switch-on de- ignition voltage source is delayed, so that a sustaining voltage is applied before a necessary amount of the initial space charge is generated for ordinary ignition. As a result of this, electrons are loosely attached to the dielectric Layers are bound, released in the gas discharge space due to field emission, and this Electrons cause an electron avalanche and rise as a result of wall tension neutralization for several to several dozen periods of maintenance voltage.

The invention is based on the object of creating a control circuit for a display device, which eliminates the above cause of attenuation of the wall spam to ensure that maintain a wall tension pattern for a long time after the power source is turned off remains and that the original wall stress pattern is reproduced when the voltage source is restored is switched on.

This object is achieved by the features of the characterizing part of claim 1

The invention is described below with reference to the drawing.

F i g. 1 is a block diagram of an example of the invention;

F i g. Figure 2 is a block diagram of another example of the invention;

F i g. FIG. 3 is a diagram of a series of waveforms for explaining the operation of the example of FIG Fig. 2 at the time of switching off a voltage source and

F i g. FIG. 4 is a diagram of a series of waveforms for explaining the operation of the example of FIG F i g. 2 at the time the voltage source is switched on.

In Fig. 1 is a block diagram of an example of the invention in which a display device 1 with a control voltage from gate circuits 2 and 3, which are used to apply a maintenance voltage

10 275

3 T 4

are seen, with a writing chip and a small electron avalanche atf Grand of the approx.

LöschspMMiwujrapeßt ^ uwlbcictemdÄTorkra- oscillation of the points. where the discharge was carried out

se 2 and 3 are controlled by a cuddly circle 7 Absence of iniiiaiUdBngsn is held back,

the. From a joke. χ. B. a well-known is efimiaiert.

Voltagesqeeae or the like, electrical energy s F i g. 2 saws a further example from the blocfcschaHfaad

a Hochspaiinungsq ^ eUenkrets 8 rad one of the elevations, with the tea, dk deneo m F i g. 1

Niederspannaagsqueltenkras 9 Ober ec «n Schaher 10 speak, are provided with the same reference symbol,

supplied, «ad a voltage w> d to an AND- This example automatically performs operations gtekh-

Krets 6 applied Ba switch ti controls the operation like those in the previous example also m dem

of the critical circle 7. If the switch It and the io case of an energy barrier Fig. 3 and 4 are

Scrapers IO are in the Βίη state, and there are diagrams for titering the operations. Ignition through an output of the AND circuit in the context of an energy lock or an opening of the

6 from eHK * ZandstromqueOe S to an ignition switch 4 to switch 10 at point in time in FIG. 3a are Ans

a desired position au! of the display device 1, input voltages from the high and low voltage

z. B. at one point on the circumferential surface of the device i ₅ voltage source 8 and 9 on NuD each after the

tion 1 or between the lines in the case of a time periods to and rf reduced, as in the F ig. 3b and

display, created In addition, a 3c display is shown. This is made possible by the installation of a condenser

drive voltage to logic circuit 7 caused by the large capacity sators, and the time periods

Low voltage source circuit 9 is applied, and a tb and ti are usually several milliseconds Tension is 8 "or longer from the high-voltage queue. The energy source interruption is

applied to the gate circuits 2 and 3, which were found by the logi- by a detector circuit 12. Exits

see creation 7 are controlled , whereby an on- of the detector circuit 12 and a delay

maintenance voltage, a write voltage and circuit 13 are supplied to an AND circuit 14, and

a voltage of the display device 1 pulls the operation of the logic circuit 7 is carried out by a

leads to be. The gate circuits 2 and 3 contain namely 15 output controlled by the AND circuit 14 Since the

groups of amplifiers and gates and the output from the detector circuit 12 to the level "0"

to reduce the maintain, write, and erase (Fig. 3d) essentially at the same time.

voltages on all or selected electrodes that is pressed as the energy source is switched off.

Create display device. the operation of the logic circuit 7 is stopped At the time of switching off the energy source 30 (FIG. 3e). After locking the operation of the logical

The first step is to switch the switch 11 to off circuit 7, no voltage is applied to the display device.

nen to the operation of the logic circuit 7 η stop- 1 applied even if the output voltage of

pen. Accordingly, a voltage on the display is not yet transmitted to the high-voltage source circuit 8.

device 1 applied although the high-voltage attenuator is F i g. 3f and ig show examples of the

source circuit 8 is still in operation. the at

Namely, and 3 derived control outputs become syn- the X- and Y- direction electrodes of the device 1

chronologically with the timing of the operation of the lo- should be created, and the maintenance

gischen circuit 7 switched off so that no voltage voltages are simultaneously with the lock of the

corresponding to an extinguishing pulse of the device 1 to- Operation of the logic circuit 7 switched off with to be led. At this point in time, the output is also reduced from the AND circuit

When the AND circuit 6 goes down to level "0", 14 to level "0", no ignition voltage is applied to the

is pressed and consequently no voltage is applied to the ignition cell 4

Ignition cell 4 applied by the ignition current source 6 and when the mains is switched on again or the

the ignition current is extinguished so that it is possible to switch 10 at the time in FIG. 4 is closed.

a neutralizing effect of the charges generated by the 45 that of the high and low voltage sources

Ignition cell diffuse, to prevent By opening control circuits 8 and 9 derived outputs respectively

of the switch 10, the output voltages of the time periods th \ and trt are steady, as shown in FIGS. 4b

the high and low voltage sources. circuits 8 and 9 and 4c. The output from the detector circuit 12

reduced to zero Even if a compensation process rises to level "1" essentially at the time this point in time will not affect the 50 point in (Fig. 4e) while the output of the

Display device 1 exercised because gate circuits 2 and delay circuit 13 are still at level "0"

3 are closed. remains so that the logic circuit 7 does not work

At the time of switching on the energy source delay time TD of the delay circuit 13, the switch 10 is first closed to select the output longer than the periods rft1 and frt and to output voltages from the high and low voltage at a point in time at which the output from the Vernungsquellecircuits 8 and 9, and then delay circuit 13 rises to the level "1" (Fig. 4d), the switch 11 is closed to the logical output of the AND circuit 14 has the level "1" circuit 7 to actuate. At the time of actuation of the (Fig. 4f) with the result that the logical circle 7 is located in the logical circle 7, the respective cutting work begins Circle 6 (Fig. 4i) also becomes level »1«. The ignition current source circuit 5 is influenced by the balancing process of the energy source and the ignition cell 4 is exerted by the control circuit. Furthermore, through begins to discharge, which supplies the initial closing of the switch 11 with an ignition voltage to the charge for the other cells. As a result, ignition cells 4 are applied so that a discharge is triggered immediately the X and K direction electrodes with such openings and initial charge maintenance voltages generated thereby are fed as shown in FIG. 4g genes are given to the other discharge cells, and 4h are shown that do not contain an unwanted erase timer which pulse the maintenance voltage applied,
with which the possibility of a neutralizing effect.

point of switching off the energy source stops very quickly and its operation at the time of switching on the Energy source starts slowly, it is also possible to use a control circuit with a relay or a timer with a high-speed opening and S with a low-speed closing build up. Furthermore, it is of course also possible to use the maintenance voltage source with fast To switch on or off rise or fall with a timing exactly synchronous with a clock pulse, while the maintenance voltage is interrupted or is at level »0«.

In the case of the invention, the display device is not supplied with a voltage which corresponds to an erasing pulse that results from a balancing process, when the power source is turned off and on, a wall tension pattern appears on the Display device maintained for a long time

as described above. Accordingly written information is maintained even while the power is interrupted or the operation is stopped at night, and a display content corresponding to the wall tension pattern can only be reproduced by turning on a power source without there being a rewrite operation Requires Since the wall charge pattern is held in this way even while the Energy source is switched off, it is also possible to use the Erase wall charges in the selected cells by a weak discharge using a voltage pen od. dgL is generated while the power source is turned off and a negative writing to be carried out by similar means. The application of voltage to the ignition cell can also be done a little before Start of the operation of the logic circuit.

For this purpose 2 sheets of drawings

Claims (3)

2310 claims: 1. Control circuit for a display device using a gas discharge space and first and second sets of electrodes arranged on both sides of the gas discharge space and intersect each other to form discharge cells at the intersections, the electrodes are isolated from the gas discharge space by dielectric layers and wall voltages are applied the area of the electrical layer at the time of discharge and with control voltages (a holding voltage, a write saving, and an erasing voltage) from a high voltage source circuit are fed via gate circuits, which are fed by the output signal of a logical Circle to be controlled in response to the input information, labeled du rc α two sets of circuits (10,11) for prevention a deletion of the wall voltages at the time of switching on and switching off a voltage source, at the time of switching off the voltage source the operation of the high voltage source circuit (8) is stopped after the operation of the logic circuit (7) is stopped, and at the time of turning on the power source, the operation of the logic circuit is started after the output control voltage from the high voltage source circuit is generated 2. Control circuit according to claim 1, characterized in that the display device (I) has a Contains ignition cell (4) which is fed with a discharge voltage from an ignition current source (S), to generate an ignition voltage for the other rows, at the time of switching off the voltage source the supply of the discharge voltage to the ignition cell simultaneously with the stopping of the Operation of the logic circuit is interrupted and at the time of switching on the voltage source the discharge voltage to the ignition cell simultaneously with starting the operation of the logic Circle is created. 3. Control circuit according to claim 1, characterized in that one of the operations of the logisehen Circuit (7) controlling circuit (11) comprising a detector circuit (12) for generating an output signal in synchronous relationship with the on-off operation of the other circuit (10) for the high voltage source circuit (8), from a delay circuit (13) for generating a delayed output signal of the on-off operation of the circuit (10) and from an AND circuit (14) consists, of which the output signal is the logical product of the output signals from the detector circuit and the delay circuit is derived.