JPH1011020A - Driving method of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the capacity of the driving circuit when conducting a gradation display by controlling the duration of the pulses applied to the electrodes of a plasma display panel(PDP). SOLUTION: The PDP is driven by cathode signals K1 to KM from a cathode driving circuit and anode current Ipn from an anode driving circuit and conducts the display by selectively discharging display cells while dividing one display screen into plural subfield screens SFi . By dividing the screen into plural subfield screens, the gradation display of the display screen is realized. The cathode driving circuit is divided into a cathode group KG1 which applies cathode signals K1 to KM/2 and a cathode group KG2 which applies cathode signals KM/2+1 to KM/2 . Then, the weighting orders of the gradation display against the subfield screens of the groups KG1 and KG2 are varied and assigned. Thus, there is no chance in which all signals K1 to KM are simultaneously applied in one subfield screen, the current Ipn is distributed timewise and the peak value is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a plasma display panel (hereinafter, referred to as a PDP) used as a display device of, for example, a wall-mounted television, and more particularly, to a method of controlling the duration of a pulse to obtain luminance gradation. The present invention relates to a method of driving a PDP for performing display.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, there is one described in the following literature. References: IEICE Technical Report, EID93-1
18 (1994-1) Yoshimichi Takahashi, "CPM Drive of 40-inch PDP" p. 37-4
2 FIG. 2 is a schematic configuration diagram of a conventional PDP and its peripheral circuits. The PDP 10 has a plurality of display anodes ₁₁ to 1.
_N: a (N a positive integer), the auxiliary anode 2 ₁ to 2 _J: and (J positive integer), the cathode 3 ₁ to 3 _M: and a (M a positive integer) and. The intersection between each display anode ₁ 1 to 1 _N and the cathode 3 ₁ to 3 _M, the display cells 4 _mn (1 ≦ m ≦ performing display by a discharge
M, 1 ≦ n ≦ N) are formed respectively, to be further intersection between the auxiliary anode 2 ₁ to 2 _J and the cathode 3 ₁ to 3 _M, auxiliary cell _{5 mj (1 ≦ j ≦ J} ) are respectively formed ing. Each display anodes ₁ 1 to 1 _N, the anode driving circuit 11 ₁ to 11 _N is,
Each is connected. The auxiliary anodes 2 _{1 to} 2 _J are commonly connected to one auxiliary anode driving circuit 12,
Cathode driving circuit 13 ₁ to 13 _M are connected to the ₁ to 3 _M.

FIG. 3 shows a conventional PD described in the above document.
FIG. 6 is a waveform chart showing a driving method of P. Each of the display anode ₁ 1 to 1
_N is a write pulse P shown in FIG.
_W is applied respectively from the anode driving circuit 11 ₁ to 11 _N. The write pulse P _W is a pulse that goes high only when a write discharge is obtained in a desired display cell 4 _mn . On the other hand, each cathode 3 ₁ to 3 _M, the scan pulse P _SCN and the sustain pulse P _SUS subsequent for scanning the respective cathode, are sequentially applied from the cathode driving circuit 13 ₁ to 13 _M. The auxiliary anode 2 ₁ to 2 _J, the auxiliary pulse P _SA is applied to the common from the auxiliary anode driving circuit 12. When such a PDP 10 is used as a display device such as a television, for example, it is necessary to perform luminance gradation display for each display cell 5 _mj . P
In DP10, the sustain pulse P following the scan pulse P _SCN
By controlling the number of _SUS based on the brightness gradation,
It enables gradation display.

FIG. 4 is a time chart showing a conventional method of driving a PDP by subfield division, in which a cathode signal composed of a scanning pulse P _SCN applied to each of the cathodes 3 _{1 to} 3 _M and a sustaining pulse P _SUS subsequent thereto. and K ₁ ~K _M, shows the time variations of the maximum value of the anode current I _P1 flowing through the display anode 1 _1. The hatched parallelogram in the figure represents the scanning pulse P _SCN and the subsequent sustain pulse P _SUS . FIG. 4 shows an example of subfield division in the case of performing 256 gradation display, and one display screen is divided into eight subfields SF1 to SF8. The subfields SF1 to SF8 have 128, 64, 3
Weighting is performed in the order of 2,16,8,4,2,1. Each cathode 3 ₁ to 3 _M, each subfield SFi
At the start of (i = 1 to 8), the scan pulse P _SCN is applied, and subsequently to the scan pulse P _SCN , the sustain pulse P _SUS for weighting each subfield SFi is applied.
The display anode 1 ₁ to 1 _N, based on the gray level of the display cell 4 _mn, corresponding subfield SFi write pulse P _W to control display / non-display for each are in synchronization with the scanning pulse P _{SC N} Applied.

[0005]

However, the conventional PDP driving method has the following problems. FIG.
As shown in the duration of each sub-field SFi, the same weighting is performed for all of the cathode 3 ₁ to 3 _M. Therefore, all of the anode current I _P1 flowing through the cathode 3 ₁ to 3 _M and the display anode 1 ₁ provided so as to intersect the subfield S the maximum weighting is performed
Corresponding to the period of F1, it becomes maximum between time τ1 and time τ2. Then, during the period from the time τ3 a relatively period of small subfields SF6~SF8 weighting to time .tau.4, anode current I _P1 hardly flows. Thus, since a large temporal change of the anode current I _P1, it was required very large capacity capable of handling large peak currents in the anode driving circuit 11 ₁ to 11 _N. An object of the present invention is to solve the problems of the prior art and to provide a method of driving a PDP that can be driven by an anode drive circuit having a capacity corresponding to the average current.

[0006]

According to a first aspect of the present invention, a first substrate, a second substrate opposed to the first substrate and a second substrate are provided. And a scan electrode group having a plurality of scan electrodes to which a scan pulse for instructing a discharge start timing and a sustain pulse for controlling a discharge sustain time subsequent thereto are applied, and the scan electrode group is opposed to the scan electrode group and Perpendicular to the scanning electrode group,
And a display electrode group having a plurality of display electrodes to which a display pulse for controlling discharge generation is applied, and a plurality of screen electrodes formed at intersections of the display electrodes and the scan electrodes. A display cell, and a discharge gas sealed in between the first and second substrates including in each of the display cells,
The following driving method is performed in the provided PDP. That is, the display screen to be displayed in gradation by the plurality of display cells is divided into a plurality of subfield screens having different weights according to luminance levels, and the scan electrode group is divided into a plurality of subelectrode groups. Then, the order of weighting of the plurality of sub-field screens is assigned to each of the plurality of divided sub-electrode groups in a different order.
And a sub-field display process for applying the scan pulse from the first electrode to the last electrode of the scan electrode group sequentially at equal time intervals to perform a display scan of the sub-field screen; and Following the scanning pulse, a luminance display process of applying the sustain pulse corresponding to the luminance level of the sub-field screen to each of the scan electrodes is performed on the plurality of sub-field screens in order, thereby displaying the display screen. indicate.

In the second invention, when assigning the weighting order of the subfield screen to each subelectrode group in the first invention, the subfield screens having the same luminance level are adjusted so as not to overlap at the same timing. Assigned in advance. According to the present invention, PD
Since the driving method of P is configured, the following operation is performed. The display screen to be displayed in gradation by the display cells of the PDP is divided into a plurality of sub-field screens in which different weighting is performed in advance according to the luminance level. The scanning electrode group is divided into a plurality of sub-electrode groups, and the order of weighting of the plurality of sub-field screens is assigned to each of the divided sub-electrode groups in a different order. Next, a scan pulse is sequentially applied at the same time interval from the first electrode to the last electrode of the scan electrode group,
A subfield display process for performing a display scan of the subfield screen is performed. Further, following the scan pulse in the subfield display processing, a luminance display processing is performed in which a sustain pulse corresponding to the luminance level of the subfield screen is applied to each scan electrode. Then, the sub-field display processing and the luminance display processing are sequentially performed on a plurality of sub-field screens, and a gray scale display screen is displayed on the PDP.

[0008]

FIG. 5 is a structural view of a PDP used in a driving method according to an embodiment of the present invention. Elements common to those in FIG. 2 are denoted by common reference numerals. . This PDP has a display electrode (for example, display anode) 1 _n (n = 1 to N, for example, N) in which a plurality of linear electrodes are arranged in parallel.
= 768) and the auxiliary anode 2 _j (j = 1 to J, for example, J =
384) and scanning electrodes (for example, cathodes) 3 arranged orthogonal to the display anode 1 _n and the auxiliary anode 2 _j .
_m (m = 1 to M, for example, M = 512).
A display cell 4 _mn (1 ≦ m ≦ M, 1 ≦ n ≦ N) for performing display by discharge is formed at the intersection of each display anode 1 _n and cathode 3 _m , and each auxiliary anode 2 _j and cathode 3 _m are formed. An auxiliary cell 5 _mj (1 ≦ j ≦ J) is also formed at the intersection with 3 _m . Each display cell 4 _mn is spatially separated from other display cells by a grid-like partition wall 6 formed of a dielectric material, and a priming slit (ignition space) 7 is formed between adjacent display cells. Are coupled through. The display anode 1 _n and the auxiliary anode 2 _j face each other on a front transparent substrate (for example, a glass substrate) 8, and the cathode 3 _m faces a rear glass substrate 9 facing the glass substrate 8. Thus, each is formed by thick film printing or the like. A discharge gas (for example, a mixed gas of helium and xenon) is sealed between the glass substrates 8 and 9. A phosphor (not shown) is applied to the inner surface of the glass substrate 8 corresponding to each display cell 4 _mn , and the display anode 1 _n in the display cell 4 _mn is coated.
When a discharge is formed between the cathode and the cathode 3 _m , ultraviolet rays are emitted and the phosphor is excited to generate visible light.

FIG. 6 is a diagram showing a P used in the embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a DP and its peripheral circuits.
Elements common to those in the middle are denoted by common reference numerals.
In the peripheral circuit of FIG. 6, the cathode driving circuit 13 ₁ in FIG. 2
13 _M are divided into two groups, and the cathode drive circuit 13 ₁
Drive unit 13A including １３13 _{M / 2} and cathode drive circuit 1
Is provided a cathode driving unit 13B including a _{3 M / 2 + 1 ~13 M} . Cathode 3 ₁ ~3 _{M / 2} is connected to the cathode driver 13A,
Cathode 3 _{M / 2 + 1} ~3 _M is connected to the cathode driver 13B. FIG. 7 is a waveform diagram showing a method of driving the PDP 10 of FIGS. 5 and 6. The 7, the auxiliary anode signal S which is applied commonly to the respective auxiliary anode 2 _j, the display anode signal A ₁ given to each display anode 1 _n, A _2, ..., and A _N,
Cathode signal applied to each cathode 3 _m K _1, K _2,
..., and K _M is shown. The auxiliary anode signal S has a pulse width τ [s] (for example, 1 μs), an amplitude Vsa [V] (for example, +100 V), and a constant period T [s] (for example, 4 μ).
s) a signal to provide an auxiliary pulse P _SA auxiliary anode 2 _j having. Cathode signal K _m consists scanning pulse P _SCN, subsequently given a period of time to the scan pulse P _SCN, and the sustain pulse P _SUS is a pulse of a different phase with the scanning pulse P _SCN. The scanning pulse P _SCN is output at the same timing as the specific auxiliary pulse P _SA , has a pulse width τ [s] substantially the same as the auxiliary pulse P _SA, and has an amplitude Vk [V] (for example, −250 V). It is a pulse.
Sustain pulse P _SUS is continuously in the period T of the auxiliary pulse P _SA [s] the same time interval T [s] is generated by a predetermined number, a scan pulse P _SCN and same pulse width, and amplitude It is a pulse. Scan pulse P _SCN and sustain pulse P
_SUS is sequentially applied to each cathode 3 _m .

The display anode signal _An is a signal for giving a write pulse _PW representing display information to each display anode 1 _n . The write pulse P _W goes to the high level indicating the write state at the same timing as the scan pulse P _SCN only when generating the address discharge in the display cell 4 _mn, and _changes to the low level indicating the non-write state in other periods. Pulse. The write pulse P _W has almost the same pulse width τ [s] as the scan pulse P _SCN, and has an amplitude Vw [V] (for example,
+50 V). Next, a general driving method of the PDP of FIGS. 5 and 6 when the waveform of FIG. 7 is applied will be described. Each of the cathodes 3 ₁ , 3 ₂ ,..., 3 _M has T [s].
A scan pulse P _SCN having a pulse width τ [s] is supplied every time. The supply of the scanning pulse P _SCN is performed by the cathodes 3 ₁ , 3 ₂ ,
.., 3 _M are sequentially performed at staggered times. Auxiliary pulse P _SA synchronized with the scanning pulse P _SCN is applied to the auxiliary anode 2 ₁ to 2 _J per T [s], the auxiliary discharge in the auxiliary discharge cell 5 _mj is, shifts together with the scanning pulse P _SCN.
Each cathode 3 ₁ to 3 _M, following the scanning pulse P _SCN,
The sustain pulse _PSUS is applied for a certain period at a timing that does not overlap with the scan pulse _PSCN . Sustain pulse P
Potential Vsa of auxiliary anode 2 ₁ to 2 _{J period SUS} is applied because 0V, the voltage applied to the auxiliary discharge cell 5 _mj is Vk - a (= 250V). Therefore, the auxiliary discharge cell 5 _mj does not discharge at this timing.

Here, when the potential of the cathode 3 _m in the m-th row becomes the potential V _SCN of the scanning pulse P _SCN by application of the scanning pulse P _SCN , the voltage (V _SA −) between the auxiliary anode 2 _j and the cathode 3 _m. V
_K) becomes 350 V, and discharge is started in the auxiliary cell 5 _mj . Due to this discharge, ions, excited atoms and the like are diffused into the display cell _4mn through the priming slit 7 in FIG. In the display cell _4mn , a discharge is immediately formed with the help of these ions and excited atoms. On the other hand, when no discharge is performed in the display cell 4 _mn (that is, when no writing is performed),
At the timing when the scanning pulse P _SCN is applied to the cathode 3 _m , the writing pulse P _W is not applied to the display anode 1 _n in the n-th column. Therefore, the voltage applied to the display cell 4 _mn is V
In _SCN (= -250 V), do not reach the voltage of a discharge, a discharge for the display cell 4 _mn is not formed. In a gas discharge, ions and excited atoms generated by the discharge remain immediately after the discharge is stopped, and the remaining ions and the excited atoms easily discharge again. Thus, for example, if the discharge in the display cells 4 _mn is formed, in the display cell 4 _mn, the sustain pulse P _SUS given subsequent to the scanning pulse P _SCN, which is the voltage lower than the normal discharge voltage Nevertheless, a discharge can be formed. As a result, in the display cell 4 _mn , the sustain discharge is continued by being intermittently pulsed by the sustain pulse _PSUS . Ultraviolet light generated by the discharge is absorbed by the phosphor in the display cell _4mn , and the phosphor emits light. When the application of the sustain pulse P _SUS to the cathode 3 _m is stopped, the sustain discharge in the display cells 4 _mn is stopped. In a display cell in which no discharge is formed, the scan pulse P
_No discharge is formed by the sustain pulse _PSUS applied subsequently to the _SCN .

[0012] Figure 1 is a time chart of a method of driving a PDP by the sub-field splitting of an embodiment of the present invention, the scanning pulse P _SCN applied to the cathodes 3 ₁ to 3 _M
And a cathode signal K ₁ comprising a sustain pulse P _SUS followed by
And ~K _M, shows the time variation of the maximum value of the anode current I _P1 flowing through the display anode 1 _1. The hatched parallelogram in the figure indicates the scanning pulse _PSCN and the sustain pulse _PSUS following it. Next, the above-mentioned general PD
A driving method of a PDP according to an embodiment of the present invention that performs gradation display by applying the driving method of P will be described. FIG.
This is an example of subfield screen division in the case of performing 56 gradation display, and one display screen is composed of eight subfield screens SF1.
To SF8. On the other hand, the cathode 3 ₁ ~3 _M
Is a sub-electrode group (eg, cathode group) KG1 from the first row to the (M / 2) th row corresponding to half of the number of cathodes;
(M / 2) The cathode group KG from the + 1st line to the Mth line
It is divided into two. The subfield screens SF1 to SF8 of the cathode group KG1 are assigned in advance with weights of 128, 64, 32, 16, 8, 8, 4, 2, and 1, respectively. Meanwhile, the cathode group KG
The weights of 2, 4, 8, 16, 32, 64, 128 and 1 are assigned to the subfield screens SF1 to SF8 of No. 2 in order, respectively. Each cathode 3 ₁ to 3 _M,
Scanning pulse P _SCN at the beginning of each sub-field screen SFi (i = 1~8) is applied, the scanning pulse P _SCN
Sustain pulse P _SUS weighting the same number of each sub-field screen SFi is applied to subsequently.

[0013] The display anode 1 ₁ to 1 _N, based on the gray level of the display cell 4 _mn, the write pulse P _W for controlling the display / non-display of the corresponding sub-field screen SFi is applied. For example, the display anode 1 ₁ and the cathode 3 ₁ of the display cell 4 ₁₁ formed in the intersection, if the gradation level 200, since 200 = 128 + 64 + 8, the sub-field screen SF1, SF2, SF
5, a write pulse P _W is applied in _{synchronization with} the timing of each scan pulse P _SCN . On the other hand, the display anode 1 ₁ and the cathode 3
_If the display cell 4 _M1 formed at the intersection of _M has the same gradation level of 200, the subfield screen SF3
A write pulse P _W is applied in accordance with the timing of each scan pulse P _SCN of SF6 and SF7. Display anode 1 ₁
Since all are provided so as to intersect with the cathode 3 ₁ to 3 _M, the anode current I flowing in the display anode 1 _1
P1 is proportional to the number of cathodes discharging at the same time,
It changes with time as shown in FIG. Thus, in the PDP driving method of this embodiment, the cathode 3 ₁ to 3 _M and divided into cathode group KG1, KG2, changing the order of the brightness display of the weighting of the sub-field screen SFi for each cathode group ing. Therefore, the discharge timing of the maximum luminance display is divided, all of the cathode 3 ₁ to 3 _M
Are not discharged at the same time. As a result, the anode current I _Pm
Is lower than that of the conventional method shown in FIG. 4 and is leveled. Therefore, there is an advantage that the PDP 10 can be driven by the anode drive circuit 11 _n having a capacity corresponding to the average anode current I _Pm. .

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, there are the following modifications. (A) In FIG. 1, it is divided into two cathode groups KG1 and KG2, but it is also possible to divide into three or more cathode groups. When the number of divisions increases, the anode driving circuit 1
1 _n and the control of the cathode drive circuit 13 _m are complicated, but the anode current I _Pm is further leveled, so that the anode drive circuit 11 _m
The capacity of _n can be further optimized. (B) In the subfield screen division shown in FIG. 1, the screen is divided into eight subfield screens SFi, but the number of subfield screens can be changed according to the number of gradation display levels. For example, in the case of a 64-gradation display, the number of subfield screens may be six.

[0015]

As described above in detail, according to the present invention, the scanning electrode group is divided into a plurality of sub-electrode groups, and the weighting order of the luminance level of the sub-field screen is changed for each sub-electrode group. . For this reason, all the scanning electrodes orthogonal to the display electrodes do not discharge at the same time, and the discharge current flowing through the display electrodes is temporally dispersed and leveled. This makes it possible to reduce the capacity of the drive circuit for supplying the display pulse.

[Brief description of the drawings]

FIG. 1 is a time chart of a method of driving a PDP by subfield division according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional PDP and its peripheral circuits.

FIG. 3 is a waveform diagram of a conventional PDP driving method.

FIG. 4 is a time chart of a conventional method of driving a PDP by subfield division.

FIG. 5 is a structural diagram of a PDP used in an embodiment of the present invention.

FIG. 6 is a configuration diagram of a PDP used in an embodiment of the present invention and peripheral circuits thereof.

FIG. 7 is a waveform diagram of a driving method of the PDP of FIGS. 5 and 6.

[Explanation of symbols]

1 ₁ to 1 _N display anode 3 _{1 to} 3 _M cathode 4 _mn display cell 10 PDP P _SCN scan pulse P _SUS sustain pulse KG1, KG2 Cathode group SF1 to SF8 Subfield screen

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Atsushi Takahashi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Claims] 1. A first substrate and a second substrate disposed opposite to the first substrate, a scan pulse for indicating a discharge start timing, which is disposed on the first substrate, and for controlling a sustaining time subsequent to the scan pulse. A scan electrode group having a plurality of scan electrodes to which a sustain pulse is applied, and disposed on the second substrate so as to face the scan electrode group and orthogonal to the scan electrode group;
A display electrode group having a plurality of display electrodes to which display pulses for discharge generation control are applied, a plurality of display cells for screen display formed at intersections of the display electrodes and the scan electrodes, A plasma display panel including a display cell and a discharge gas sealed between the first and second substrates, wherein a display screen to be displayed in gradation by the plurality of display cells is set to a brightness level in advance. The scanning electrode group is divided into a plurality of sub-electrode groups, and the weighting of the plurality of sub-field screens is performed for each of the plurality of divided sub-electrode groups. The order is assigned in a different order, and the scan pulse is sequentially applied from the first electrode to the last electrode of the scan electrode group at equal time intervals, and the sub-field is applied. A subfield display process for performing a scan scan of a field screen; and a brightness display process for applying the sustain pulse corresponding to the brightness level of the subfield screen to each of the scan electrodes following the scan pulse in the subfield display process. The display screen is displayed by sequentially performing the steps on the plurality of subfield screens. 2. The plasma display according to claim 1, wherein sub-field screens having the same luminance level are adjusted and assigned in advance to said different sub-electrode groups so as not to overlap at the same timing. Panel driving method.