JP3207193B2 - Discharge display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a plasma display device having a flat information display unit for performing display by selective light emission of discharge cells arranged in a matrix form. The present invention relates to a plasma display device.

[Conventional technology]

Conventionally, as this type of apparatus, for example, Japanese Patent Application Laid-Open No. 60-230698
Is described in Japanese Patent Application Publication No. FIG. 2 is a partial cross-sectional view of a discharge cell portion of the conventional discharge display device, and FIG. 3 is a partially broken perspective view thereof. As shown in the drawing, the conventional apparatus includes an upper surface portion E in which a plurality of anode electrodes 6 are provided on a lower surface of a window glass plate 7, and a half portion, for example, an upper half portion of the base glass plate 1 on the base glass plate 1. Arrange two trigger electrodes 2a and 2b covering the lower half,
A dielectric glass layer 3 is printed thereon as an insulating layer, and a plurality of cathode electrodes 4 extending perpendicular to the anode electrode 6 are provided thereon. The anode electrode 6 and the cathode electrode 4 are combined so as to be orthogonal to each other, and the periphery thereof is sealed and the inside thereof is replaced with a rare gas such as Ne.

FIG. 4 is a schematic wiring diagram showing electrodes and a driving circuit of the discharge display device, and FIG. 5 is a circuit diagram of a trigger circuit 17 in FIG. FIG. 6 is a time chart showing the operation of the circuit of FIG.

Each phase alternates between a trigger period and a pause period. While one phase is in the trigger period, the other phase is in the idle period.

During the trigger period, as shown in FIG. 6, the potential of the A-phase trigger electrode 2a is raised to the anode on-level potential (VA), and the cathode electrodes 4 shared by the A phase are sequentially turned on (VE). ). That is, the potential of the cathode electrode 4 is sequentially turned on (negative direction), for example, as K1, K2, K3,. Then, a small preliminary discharge (trigger discharge) is generated between the cathode electrode 4 having the ON potential and the trigger electrode 2a.

In the idle period, the A-phase trigger electrode 2a is once lowered to the -VA potential level to cause a regenerating discharge, then raised to the intermediate potential VE level, and then maintained at this level until the end of the idle period. Here, the regenerative discharge means that the negative charge (electrons) accumulated on the surface of the trigger insulating layer (dielectric glass layer 3) by the trigger discharge at the fall of the trigger voltage is neutralized and the potential on the surface of the dielectric glass layer 3 is reduced. In the positive direction to prepare for the next trigger discharge.

Next, a circuit for generating a trigger voltage will be described.
In FIG. 5, first, a signal is input to the terminal S1, the transistors Q2, Q3, and Q5 are turned on, the other transistors are turned off, and the voltage VA is stored in the precharge capacitor CP. At that time, the output terminal TE connected to the trigger electrode 2 is at the intermediate potential VE (pause period). Next, in the trigger period, a signal is input to the terminal S2 to turn on the transistors Q4 and Q6 and turn off the other transistors. Then, the potential of the trigger electrode 2 rises to VA, and the potential of both ends of the precharge capacitor CP becomes the VA potential on the minus side and the 2VA potential on the plus side. Next, in the regeneration discharge period, a signal is input to the terminal S3 to turn on the transistor Q1 and turn off other transistors. The potential at both ends of the precharge capacitor CP is at the VE potential level on the + side, and is at the -VA potential on the-side because the voltage of VA is originally applied. Therefore, the potential of the trigger electrode 2 becomes -VA potential.

Such circuits are provided for two phases, A-phase and B-phase, respectively.
The phase trigger waveform is connected to the A-phase and B-phase trigger electrodes.

[Problems to be solved by the invention]

However, the device having the above structure is divided into the A phase and the B phase, so that the boundary between the A phase and the B phase is easily affected by the trigger electrode 2 of another phase, and the brightness of the trigger discharge (preliminary discharge) is increased. In this case, there is a problem that unevenness occurs (here, referred to as back luminance separately from information display discharge luminance).

Hereinafter, this point will be described with reference to FIG. This figure shows a state where the B-phase is selected and before the cathode electrodes 4a and 4b on the B-phase trigger electrode 2b are scanned. From this figure, it can be seen that the amount of charges charged in the vicinity of the cathode electrode 4b at the end of the phase is different from that of the cathode electrode 4a which is not at the other end. As a result, there is a difference in the rise time to the main discharge when scanning is performed, which causes flickering.
The same can be said for the cathode electrodes 4c and 4d when the phase A is selected. Also, a small discharge can be visually recognized at the time of a trigger discharge or a regenerating discharge, but only the dielectric glass layer 3 between the cathode electrodes 4b and 4c has a different back luminance from other regions, resulting in display unevenness and deterioration of display quality.

In the prior art, the trigger circuit is configured to generate a potential (VA) for generating a trigger discharge and a potential (-) for generating a regenerating discharge.
VA), and then it is necessary to generate the potential of three values of the potential during waiting (VE), the structure of the trigger circuit is complicated,
Also, many control input signals are required.

The present invention has been made in order to eliminate the above-mentioned problems such as the unevenness of the brightness at the phase boundary, the complexity of the structure, and the need for a large number of input signals. It is an object to provide a display device which is simple and requires a small number of control inputs.

[Means for solving the problem]

The present invention provides a single trigger electrode corresponding to all cathode electrodes in a display panel, applies a constant trigger voltage to the trigger electrode during a period in which the cathode electrode is being scanned, and supplies a trigger voltage during the scanning of one frame. A regenerating discharge is generated during the scanning period.

[Action]

As described above, since the trigger electrode has a single phase, display unevenness at a boundary between the phases can be eliminated. Further, the trigger circuit only needs to generate two potentials, a potential for causing a trigger discharge and a potential for causing a regenerating discharge, so that the structure is simplified and the number of control input signals is reduced.

〔Example〕

FIG. 1 is a partial cross-sectional view of a discharge cell portion of a discharge display device according to one embodiment of the present invention, and FIG. 8 is a partially cutaway perspective view thereof.

The display cell portion of this embodiment has a base portion C and an upper surface portion D. The base portion C is formed on the base glass plate 8, a single trigger electrode 9 formed on the base glass plate 8, a dielectric glass layer 10 formed thereon as an insulating layer, and formed thereon. And a plurality of strip-shaped cathode electrodes 11 extending in parallel with each other, and partition walls 12 formed thereon and extending orthogonal to the cathode electrodes 11 to form a plurality of discharge cells. The trigger electrode 9 is formed so as to cover substantially the entire surface of the base glass plate 8 and faces all the cathode electrodes 11 on the base glass plate 8.

On the other hand, the upper surface portion D has a window glass plate 14 and an anode electrode 13 formed of a transparent conductive material on the window glass plate 14.

Of the above, the trigger electrode 9, the dielectric glass layer 10, the cathode electrode 11, and the partition 12 are formed by thick-film printing, and the printed portion is fired at, for example, about 600 ° C. to obtain the base C. Can be

Then, the base C and the top D formed in this way are combined to face each other, the periphery is sealed with low-melting glass, and the inside is replaced with a rare gas such as Ne, thereby forming the discharge display section DP. obtain.

Next, the control drive circuit section will be described. FIG. 9 is a schematic wiring diagram showing an electrode and a drive circuit of the present embodiment,
FIG. 10 is a circuit diagram of the trigger circuit 20. FIG. 11 shows the setting of the on and off potentials of the anode and the cathode.

As shown in FIG. 9, the discharge display section DP includes an anode driving circuit 18, a cathode scanning circuit 19, and a trigger circuit.
Connected to 20. Also, these circuits 18, 19 and
20 is connected to the control circuit 21. The control circuit 21 supplies the anode drive circuit 18 with the video signal and the anode ON potential VF,
An anode off potential VG is supplied, and the anode drive circuit 18 sequentially controls the selection of the anode electrodes. The control circuit 21 also supplies the cathode scanning circuit 19 with the cathode off potential.
VH and the cathode-on potential VI are supplied, and scanning of the cathode electrode by the cathode scanning circuit 19 is controlled. The control circuit 21 further supplies control signals S1 and S2 to the trigger circuit 20 to control application of a voltage to the trigger electrode 9 by the trigger circuit 20.

Cathode electrodes 11 are alternately left and right cathode scanning circuits
Connected to 19, a negative voltage is applied line-by-line from top to bottom,
Similarly, data, that is, a video signal (potential VF is “1” and potential VG is “0”) is supplied to the anode electrodes 13 connected to the upper and lower anode driving circuits 18 every other one, so that the anode electrode 13 and the cathode electrode 11 are connected. Causes a selective display discharge.

Next, the drive timing will be described. FIG. 12 (a) is a time chart showing the voltages applied to the trigger electrode 9 and the cathode electrode 11, and K1 to KN are the voltages applied to the respective cathode electrodes 11, that is, the cathode electrodes 11
3 shows the voltage for scanning. FIG. 12 (b)
12 is an enlarged time chart showing a period Tx in FIG.

In FIG. 12, the first cathode electrode 11 (the cathode electrode to which the voltage K1 is applied) is selected at a timing t1. That is, the potential of the cathode electrode 11 is the cathode off potential.
The potential changes from VH (eg, 65V) to the ON potential VI (eg, 0V).
Next, at timing t2, the second cathode electrode 11 (the cathode electrode to which the voltage K2 is applied) is selected. Similarly, the cathode electrodes 11 are sequentially selected in the same manner, and at the timing t3, the last cathode electrode 11 (the cathode electrode to which the voltage KN is applied)
Is selected, and the selection of the last cathode electrode 11 ends at timing t4. Thus, scanning of one frame is completed.

While one cathode electrode 11 is selected, the anode electrodes 13 are sequentially selected. FIG. 12 (b) shows the sequential selection of the anode electrode 13 while an arbitrary cathode electrode 11, that is, the cathode electrode 11 to which the voltage Kx is applied is selected.

As shown, the potential of the cathode electrode 11 changes from the cathode off potential VH (for example, 65 V) to the on potential VI (for example, 0 V), during which the anode electrode 13 is sequentially selected. During this time, the video signal is continuously supplied, and the video signal at each instant is applied to the selected anode electrode 13. The video signal has an on level (for example, 180 V) and an off level (for example, 115 V). A1 in FIG. 12 (b)
The pulses of .about.AM indicate that each anode electrode 13 has been selected, but do not indicate that the video signal is on level.

If the video signal is at the ON level while each anode electrode 13 is selected, a discharge (display discharge: main discharge) occurs between the anode electrode 13 and the cathode electrode 11. No discharge occurs between the anode electrode 13 and the cathode electrode 11 to which the off level is applied.

After the scanning of one frame is completed, a non-scanning period is provided until the operation of the next frame starts, and a regeneration discharge is generated during the non-scanning period. That is, the last cathode electrode
A predetermined time, for example, 100 after the selection of 11 is completed (t4)
The voltage applied to the trigger electrode for a predetermined period, for example, 300 μs from the time (t5) when μs has elapsed (t5), that is, until timing t6, is (VI−VF). The operation during the regenerating discharge will be described later in detail.

Thereafter, when another predetermined period, for example, 150 μs has elapsed (t1), scanning of the next frame is started. That is, 1
The second cathode electrode 11 is selected. Hereinafter, the same operation as described above is repeated.

Next, the operation of the trigger electrode 9 for assisting the display discharge and for generating the display discharge more stably will be described.

13 (a) to 13 (f) show arbitrary cathode electrodes in FIG.
11, that is, a discharge cell formed at the intersection of the cathode electrode 11 to which the voltage Kx is applied and an arbitrary anode electrode 13, i.e., the anode electrode 13 selected at the timing Ay, also at timings ta to tf in FIG. It is a figure showing operation in each.

After one frame of scanning begins, the cathode electrode
At the timing until the on-potential Vx is applied to 11, for example, at timing ta in FIG. 12, the trigger electrode 9 is at the VF potential (anode-on potential) and the cathode electrode 11 is at VH, as shown in FIG. Since the potential (cathode off potential), the dielectric glass layer 10 is charged positive (+) on the cathode electrode 11 side and negative (-) on the trigger electrode 9 side.

Next, when the cathode electrode 11 is selected at the timing tb and becomes the on-potential VI, as shown in FIG. 13 (b), an electric field capable of discharging is generated between the surface of the dielectric glass layer 10 and the cathode electrode 11, and a minute electric field is generated. Discharge (trigger discharge) occurs. This discharge is terminated when there is no more charge on the dielectric glass layer 10 due to an alternating current (AC) discharge.

While the on-potential is being applied to the cathode electrode 11, the anode electrode 13 is sequentially selected and a video signal is applied. Anode electrode to which ON level (VF) signal is applied
13 and the selected cathode electrode 11 intersect, a main discharge occurs in the discharge cell as described above (timing tc:
FIG. 13 (c)). The transition to the main discharge is promptly performed due to the space charge due to the trigger discharge described above, and the time (delay) from the time when the cathode electrode 11 becomes the ON potential is 1 μs or less.

When the selection of the anode electrode passing through the discharge cell in which the main discharge has occurred is completed and the anode electrode is at the off potential VG (timing td), the main discharge is extinguished (FIG. 13 (d)).

Next, at the timing te, the selection of the cathode electrode 11 passing through the discharge cell ends, and the cathode electrode is turned off (V
H). However, the dielectric glass layer 10 remains negatively charged due to the trigger discharge with the cathode electrode 11. When the scanning of one frame is completed, the dielectric glass layer 10 is in such a state as a whole (FIG. 13 (e)).

Therefore, a regenerating discharge is generated at the end of one frame.
That is, at the timing tf, the potential of the trigger electrode 9 is changed to (VI-V
F). By doing so, inside the dielectric glass layer 10, as shown in FIG. 13 (f), the cathode electrode 11 side becomes negative (-) and the trigger electrode side becomes positive (+), and the surface of the dielectric glass layer 10 and the anode electrode 13 And a regenerating discharge occurs between them. Thereby, the dielectric glass layer 10 is electrically neutralized as a whole.

Even after the trigger electrode is returned to the anode-on potential VF, the timing ta, the dielectric glass layer 10 maintains an electrically neutralized state as a whole, and therefore, when the cathode electrode is selected in the next frame, Trigger discharge occurs in the same manner as described above.

The sequential selection of the anode electrode, the scanning of the cathode electrode, and the driving of the trigger electrode are performed under the control of the control circuit 21 as described above.

FIG. 10 is a schematic diagram showing a trigger circuit for generating a potential applied to the trigger electrode 9. As shown, this circuit comprises a control input terminal for receiving first and second control signals S1 and S2 from a control circuit 21, an output terminal TE connected to a trigger electrode, transistors Q7 to Q10, a diode D3 and D4, capacitors C1 and C2, and resistors R9-R1
With 2. The bases of transistors Q7 and Q9 are connected to receive control signal S1, and the bases of transistors Q8 and Q10 are connected to receive control signal S2.

The emitters of transistors Q7 and Q9 are resistors
It is connected to the power supply terminal of the anode ON potential (VF) via R11 and R9. On the other hand, transistors Q8 and Q10
Are connected to the collectors of the transistors Q7 and Q9, respectively, and the emitter of the transistor Q10 is connected to the power supply terminal (node of the ground potential) of the anode off potential (VI). The emitter of the transistor Q8 is connected to the anode off potential (VD) through the diodes D3 and D4 connected in series.
Connected to the power terminal of I). Diodes D3 and D
The capacitor C1 is connected between the interconnection point 4 and the interconnection point between the transistors Q9 and Q10.

First, during the trigger discharge period (FIG. 12), the transistors Q7 and Q9 are turned on by the control signal S1, and the other transistors are turned off. Therefore, the potential VF from the power supply is output to the output terminal TE. Since the potential VF is applied to the positive side of the capacitor C1 and the potential VI is clamped to the negative side, the capacitor C1 is charged.

Next, during the regeneration discharge period, the transistors Q8 and Q10 turn on,
Other transistors are off. Since the positive side of the capacitor C1 sharply drops to the potential VI, the negative side sharply drops to (VI-VF). This potential is transmitted to the upper electrode in the drawing of the capacitor C1 via the diode D3 and is held. Then, the voltage is transmitted to the output terminal TE via the transistor Q8, and the potential of the output terminal also becomes (VI-VF).

The above series of operations can be completed with only two control signals.

According to the embodiment described above, VFI, VFG, VHI of FIG.
Were set to 180 V, 65 V, and 65 V, respectively, and an information display discharge was performed to achieve a luminance of 22 cd / m ² and a contrast ratio of 100: 1.

As described above, in the related art, since the trigger electrode is divided into multiple phases, there is a problem that display unevenness occurs at a boundary between the phases.
As shown in FIG. 9, since the trigger electrode has a single-phase structure, display unevenness can be eliminated.

The trigger circuit for driving the trigger electrode 9 has a simpler structure according to the present invention, as is apparent from a comparison between FIG. 5 (conventional example) and FIG. 10 (the present invention). this is,
In the prior art, the trigger circuit needs to generate three potentials: a potential (VA) for causing a trigger discharge, a potential (-VA) for causing a regenerative discharge, and a potential (VE) during a quiescent period. This is because, in the present invention, it is sufficient to generate two potentials, a potential (VF) for causing a trigger discharge and a potential (VI-VF) for causing a regeneration discharge.

Also, three signals to be applied to the trigger circuit were conventionally required, but in the present invention, two signals are sufficient.

〔The invention's effect〕

As described in detail above, according to the present invention, the following effects are obtained by using a single-phase trigger electrode.

(1) In the case of multi-phase, luminance unevenness due to a difference in trigger discharge between the phases occurred. However, in the present invention, this was eliminated and the display quality was improved.

(2) A single trigger circuit is sufficient for a multi-phase, whereas a plurality of trigger circuits are required, and light weight, miniaturization, and cost reduction are possible.

(3) The trigger circuit only needs to generate two potentials, and its configuration can be simplified.

(4) The structure of the panel is simplified, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a discharge cell portion of a discharge display device according to one embodiment of the present invention, FIG. 2 is a partial cross-sectional view of a discharge cell portion of a conventional discharge display device, and FIG. FIG. 4 is a schematic wiring diagram showing the electrodes of the discharge display device of FIG. 2 and its driving circuit, FIG. 5 is a circuit diagram of a trigger circuit in FIG. 4, and FIG. 6 is a trigger of FIG. 7 is a time chart showing the operation of the circuit, FIG. 7 is a view for explaining display unevenness at a boundary between the phases, FIG. 8 is a partially cutaway perspective view of the discharge cell portion of FIG. 1, and FIG. FIG. 10 is a schematic wiring diagram showing the electrodes of the discharge display device of FIG. 1 and its driving circuit. FIG. 10 is a circuit diagram of the trigger circuit 20. FIG. 11 is a diagram showing ON and OFF potential settings at the anode and cathode. 12 (a) and (b) show the tie showing the driving of the trigger, cathode and anode electrodes. FIGS. 13 (a) to 13 (f) are diagrams showing the operation of one discharge cell at timings ta to tg in FIG. DP: discharge display section, 9: trigger electrode, 11: cathode electrode, 13: anode electrode, 18: anode drive circuit, 19: cathode scan circuit, 20: trigger circuit, 21: control circuit.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takashi Komatsu 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A 1-137537 (JP, A) JP JP-A-60-225898 (JP, A) JP-A-60-230698 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 17/49 G09G 3/28 G09G 3/282

Claims (1)

(57) [Claims] 1. A discharge display device having a display cell portion including a base portion and an upper surface portion, wherein the base portion includes: a base glass plate; a single-phase trigger electrode formed on the base glass plate; A plurality of cathode electrodes formed on the trigger electrode with an insulating layer interposed therebetween and extending substantially in parallel with each other. The upper surface portion includes a window glass plate and an anode electrode. A trigger discharge is generated by applying a potential to turn on the anode electrode to the trigger electrode during scanning of one frame, while intersecting and opposing the cathode electrode at the base portion. A potential obtained by subtracting a potential for turning on the anode electrode from a potential for turning on the cathode electrode between the scanning of one frame and the scanning of the next frame. Discharge display device characterized by having a trigger circuit for generating a reproduction discharge by applying to the trigger electrode.