JP2001210238A - Ac type plasma display panel and method for driving the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a visibility of a black display in a panel display disposed at dark site is deteriorated, since initializing discharges are generated twice at every sub-fields in an AC type plasma display panel. SOLUTION: A final retaining operation of the retaining period time in at least one sub-field of a plurality of sub-fields for constituting one field, and an initializing operation during an initializing period of a sub-field continuous to the sub-field are carried out simultaneously, so that a brightness in the black screen display without light emission display is extremely lowered to considerably improve the visibility of black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC type plasma display panel used for image display of a television receiver, a computer terminal or the like, and a method of driving the same.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view of a main part of a conventional AC surface discharge type plasma display panel. FIG. 9B shows FIG.
It is a BB sectional view of (a).

As shown in FIG. 9, in a conventional AC surface discharge type plasma display panel (hereinafter, referred to as a panel) 1, a glass front substrate 3 and a glass rear substrate 4 face each other with a discharge space 2 interposed therebetween. It is arranged. On the front substrate 3, an electrode group consisting of a pair of strip-shaped scan electrodes 7 and sustain electrodes 8 covered with a dielectric layer 5 and a protective film 6 is arranged in parallel with each other.

On the rear substrate 4, strip-shaped data electrodes 9 are arranged in parallel with each other in a direction orthogonal to the scanning electrodes 7 and the sustaining electrodes 8, and these data electrodes 9 are separated from each other.
In addition, a strip-shaped partition 10 for forming the discharge space 2 is provided between the data electrodes 9. Further, a phosphor layer 11 is formed from above the data electrode 9 to the side surface of the partition wall 10. Further, the discharge space 2 is filled with a mixed gas of xenon (Xe) and at least one of helium (He), neon (Ne), and argon (Ar).

[0005] The panel 1 is designed to view an image display from the front substrate 3 side, and scan electrodes 7 in the discharge space 2.
The phosphor layer 11 is excited by ultraviolet rays generated by the discharge between the electrode and the sustain electrode 8, and the visible light from the phosphor layer 11 is used for display light emission.

The distance between the scanning electrode 7 and the sustaining electrode 8 (hereinafter, referred to as a distance)
Conventionally, dp (referred to as a sustain discharge gap) is smaller than the height of the barrier ribs 10 so that a surface discharge easily occurs between the scan electrode 7 and the sustain electrode 8. For example, when the height of the partition wall 10 is 150 μm, the sustain discharge gap dp is 8
It was designed to be 0-100 μm. In such a short gap discharge, only a so-called negative glow having low ultraviolet radiation efficiency could be used, and the luminous efficiency and luminance of the panel were low.

On the other hand, a panel in which the sustain discharge gap dp is enlarged to, for example, 600 μm is disclosed in JP-A-11-14 / 1999.
No. 3425 is disclosed. Sustain discharge gap d
If p is increased to this extent, the positive column portion of the discharge can be used, and the luminous efficiency of the panel can be greatly increased. On the other hand, driving becomes difficult because the start voltage of the sustain discharge increases. To solve this, as shown in FIG. 10, a pulse voltage is alternately applied to the scan electrode 7 and the sustain electrode 8, and the data electrode 9 is synchronized with these pulses.
Also, a short pulse is applied. By applying a short pulse to the data electrode 9, a preliminary discharge is first performed between the data electrode 9 having a narrow electrode interval and the scan electrode 7 or the sustain electrode 8, and then a preliminary discharge is performed between the data electrode 9 and the scan electrode 7 having a wide electrode interval. Main discharge is started between sustain electrode 8 and sustain electrode 8. As a result, main discharge can be generated at a relatively low sustain voltage.

[0008] Here, the positive column indicates a filament-shaped discharge generally generated in a discharge space having a long distance between electrodes.

Next, FIG. 12 shows an electrode arrangement diagram of this panel. As shown in FIG. 12, the electrode arrangement of this panel is m
× n matrix configuration, m columns of data electrodes D1 to Dm are arranged in the column direction, and n rows of scan electrodes SCN1 to SCNn and sustain electrodes SUS1 to SU in the row direction.
Sn is arranged.

A conventional driving method for driving this panel is disclosed in US Pat. No. 5,745,086.
FIG. 11 shows an operation drive timing diagram of the conventional drive method. In this driving method, one field period is composed of eight subfields in order to perform 256 gradation display, and the first to eighth subfields include an initialization period, a writing period, a sustain period, and an erasing period. , Respectively.

In this conventional driving method, in a so-called black screen display in which no discharge cells are displayed on a panel, a write discharge in a write period, a sustain discharge in a sustain period, and an erase discharge in an erase period do not occur. Only the initializing discharge in the initializing period occurs, the initializing discharge is weak, and the discharge light emission is also weak, so that there is a feature that the contrast of the panel is high. For example, 480
42 inches A in a matrix configuration of 852 × 3 columns in rows
In a C-type plasma display panel, when one field period is composed of eight subfields and 256 gradations are displayed, the emission luminance due to two setup discharges in the setup period of each subfield is 0.15 cd. / M
^{Was 2} . Accordingly, the sum of the eight subfields is 0.15 × 8 = 1.2 cd / m ² and the maximum luminance is 420 cd / m ² , so that the contrast of this panel is 420 / 1.2: 1 = 350: 1, which is a very high contrast value.

[0012]

However, in the above-mentioned conventional configuration, since a pulse is always applied to the data electrode 9, a large stray capacitance exists between the data electrode 9, the scanning electrode 7 and the sustaining electrode 8. For example, 42
Taking a mold panel as an example, several tens of watts of reactive power are generated, so that there is a problem that it is necessary to add many circuit components in order to reduce the power of the drive circuit for the data electrodes 9.

Further, in the above-described conventional configuration, when a panel display is performed under normal illumination, a considerably high contrast is obtained. However, two initializing discharges always occur in each subfield. When the panel is displayed in a dark place, the brightness is so high that even the light emission due to this weak initializing discharge is conspicuous, and the visibility of the black display is poor when the panel is displayed in a place that is not very bright. Had.

The present invention solves the above-mentioned conventional problems. Even when the sustain discharge gap is lengthened, the visibility of the black display when the panel is displayed without increasing the reactive power and in a non-bright place. Without lowering
An object of the present invention is to provide an AC-type plasma display panel having high luminous efficiency and a driving method thereof.

[0015]

In order to achieve this object, an AC type plasma display panel according to the present invention has a first electrode and a second electrode which are covered with a dielectric layer and are formed in parallel with each other. A substrate and a second substrate in which a third electrode is formed in a direction orthogonal to the first electrode are disposed to face each other with a discharge space interposed therebetween, and the distance between the first electrode and the second electrode is greater than the height of the discharge space. It has a configuration in which the discharge between the first and second electrodes and the third electrode forms a part of the sustain discharge.

In order to achieve this object, a method of driving an AC type plasma display panel according to the present invention is characterized in that one field period is constituted by a plurality of subfields having an initialization period, a writing period and a sustaining period. There is a configuration in which display is performed, and a final sustain operation of a sustain period in at least one of the plurality of subfields and an initialization operation of an initialization period of a subfield subsequent to the at least one subfield are simultaneously performed. are doing.

[0017]

According to this configuration, a discharge is first started in a counter discharge space having a height of a discharge space shorter than a distance between a first electrode and a second electrode, and is extended to the other counter discharge space. Things. That is, it is possible to use a positive column discharge in an extended discharge space while starting discharge at a relatively low voltage, and to provide an AC-type plasma display panel having improved luminous efficiency without increasing discharge voltage and a driving method thereof. Can be.

Further, according to this configuration, in the initializing period in the first subfield, the initializing discharge to be performed regardless of the presence or absence of the light emitting display is performed only by the weak opposing discharge between the first electrode and the third electrode. The initializing discharge in the initializing period in the sub-fields after the second sub-field is performed as an initializing operation for the next sub-field only for the discharge cells for performing the light-emitting display, and for the discharge cells not performing the light-emitting display. By not causing such an initializing discharge, the luminance in a so-called black screen display without light emission display can be reduced to 1
AC type plasma that can greatly improve the visibility of black and greatly enhance the contrast of the panel because it can be made only the emission luminance of the initialization discharge of one of the subfields constituting the field. A method for driving a display panel can be provided.

[0019]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a main part of a panel according to an embodiment of the present invention. 2 is a cross-sectional view taken along line CC of FIG. 1, and FIG.
It is DD sectional drawing of.

As shown in FIGS. 1 to 3, a panel 12 according to an embodiment of the present invention has a front substrate 3 made of glass and a rear substrate 4 made of glass opposed to each other with a discharge space 2a interposed therebetween. ing. A strip-shaped first electrode 1 covered with a first dielectric layer composed of a dielectric layer 5 and a protective film 6 is provided on the front substrate 3.
A plurality of electrode pairs each composed of 4 and the second electrode 15 are arranged. As the protective film 6, a material having a high secondary electron emission coefficient such as magnesium oxide (MgO) is used.

On the back substrate 4, a plurality of strip-shaped third electrodes 1 are arranged in a direction orthogonal to the first electrode 14 and the second electrode 15.
6 are arranged, and a strip-shaped partition wall 10 for isolating each third electrode 16 and forming a discharge space 2a is formed as a third partition.
It is provided between the electrodes 16. In addition, the adjacent partition 1
Between 0, a strip-shaped phosphor layer 11 is formed to cover the side surfaces of the third electrode 16 and the partition wall 10.

The discharge space 2a is filled with a mixed gas of at least one of He, Ne and Ar and Xe.

In the panel 12 of the present embodiment, the gap between the first electrode 14 and the second electrode 15 is a gap dss, and the surface of the phosphor layer 11 and the surface of the protective film 6 on the center line of the third electrode 16. (Hereinafter referred to as the opposing discharge gap), that is, when the height of the discharge space 2a on the center line of the third electrode 16 is dsa, dss> dsa. The first opposed discharge space refers to a discharge space between the first electrode 14 and the third electrode 16, and the second opposed discharge space refers to a discharge space between the second electrode 15 and the third electrode 16. I do. Table 1 shows an example of the panel design parameters according to the present embodiment.

[0025]

[Table 1]

The distance between the electrodes for performing the sustain discharge in the conventional surface discharge type panel, that is, the distance between the scanning electrode 7 and the sustaining electrode 8 is 80 to 100 μm, whereas in the panel of the present embodiment, it is mainly The discharge gap dss is set to 400 μm, which is almost five times as large as that of the related art. Therefore, when the panel of the present embodiment is driven by the conventional driving method, the voltage Vfss for starting the sustain discharge becomes extremely high. Therefore, in the present embodiment, the third electrode 16 is used to effectively lower the Vfss to perform the sustain discharge. This sustain discharge is not a conventional surface discharge, but rather a counter discharge. It is.

As described above, in the present embodiment,
Since the discharge cell has a long distance dss between the first electrode 14 and the second electrode 15, a so-called positive column discharge can be formed to obtain high luminous efficiency. However, since the distance dss between the electrodes is long, there is a problem that the discharge voltage increases.
Therefore, first, a discharge is started in the opposing discharge space having the height dsa of the discharge space, and is extended to the other opposing discharge space, so that the positive column discharge can be used at a relatively low discharge voltage. As a result, in the panel of the present embodiment, 2
A high luminous efficiency of 1 lm / W or more was obtained, and the luminous efficiency of the conventional panel was 1 lm / W or less.

Next, a description will be given of a driving method for driving the panel 12 according to the present embodiment by forming a one-field period by a plurality of sub-fields and performing gradation display.

FIG. 4 shows an operation drive timing chart for driving the panel of the embodiment of the present invention, and FIG. 5 shows an electrode arrangement diagram of the panel of the embodiment of the present invention. In the electrode arrangement diagram of the panel shown in FIG. 5, the first electrode 14 is connected to the scan electrode SCN1.
To SCNn and the sustain electrodes SUS1 to SUS as the second electrodes 15.
n, and an arrangement diagram in which the third electrodes 16 are data electrodes D1 to Dm, which is the same as the electrode arrangement diagram of the conventional panel shown in FIG.

As shown in FIG. 4, one field period is
It has an initializing period, a writing period, a sustaining period, and an erasing period, and is composed of first to eighth subfields, thereby displaying 256 gradations.

Of these eight subfields, the first
In the seven sub-fields except for the sub-field of, the initialization operation in the initialization period is performed simultaneously with the final maintenance operation in the sustain period of the previous sub-field. That is, in the first subfield, the initialization period is provided independently, and the writing period and the sustain period are provided, but the erasing period is not provided. In addition, at the same time as the sustaining operation by applying the last sustaining pulse voltage in the sustaining period, the initialization operation in the initialization period of the second subfield is performed.

Similarly, in the subsequent third to seventh subfields, an initialization period, a writing period, and a sustain period are provided, but an erasing period is not provided. This is performed simultaneously with the last sustain operation of the sustain period of the previous subfield.

In the eighth subfield,
The sustain period is provided independently, and the erase period is provided after the sustain period. Further, the initializing operation in the initializing period of the eighth subfield is performed simultaneously with the final maintaining operation of the sustaining period of the seventh subfield.

In order to display image data, different signal waveforms are applied to the respective electrodes during the initialization period, the writing period, and the sustaining period. FIG. 6 is a partial extraction of the driving waveform of the panel of this embodiment shown in FIG.
6A shows the driving waveform of the first sub-field of FIG. 4 and the discharge current flowing through the first electrode 14, and FIG. 6B shows the driving waveform of the second to eighth sub-fields of FIG.
2 shows a discharge current flowing through the circuit.

Referring to FIG. 6A, a description will be given of a state of the first sub-field in FIG. 4 until the last part of the initialization period, the writing period and the sustain period.

In the initialization period shown in FIG.
The first electrode is applied with a ramp voltage that changes three times from a voltage lower than the firing voltage to a voltage higher than the firing voltage with respect to the third electrode, and a binary positive voltage is applied to the second electrode. By doing so, transient light emission discharge is suppressed.

Hereinafter, the initializing operation in the initializing period of the first subfield will be described by dividing the ramp waveform applied to the first electrode into the first half, the middle, and the second half.

In the first half of the initialization period in FIG. 6A, a voltage of 0 V is applied to the first electrode 14 and to the third electrode 16.
By applying a ramp voltage that gradually decreases from (V) to Vn (V) and applying a voltage of 0 (V) to the second electrode, a weak discharge occurs only in the first opposed discharge space. still,
Vn (V) is a negative voltage. This discharge causes the first
Initial charges for subsequent operations are formed in the opposing discharge space. The reason for applying a voltage falling to the first electrode 14 with respect to the third electrode 16 is to facilitate the start of discharge by using the protective film 6 having a relatively large secondary electron emission coefficient as a cathode. It is.

In the middle of the initialization period in FIG. 6A, a rising voltage having a relatively large amplitude is applied to the first electrode 14 with respect to the third electrode 16, and a voltage 0 is applied to the second electrode.
By applying (V), a discharge is generated only in the first opposed discharge space which is larger than the first half of the initialization period. As a result, negative charges are accumulated in the protective film 6 on the first electrode 14.

In the latter half of the initialization period shown in FIG. 6A, a ramp voltage falling with respect to the third electrode 16 is applied to the first electrode 14, and the voltage Vh is applied to the third electrode 16 with respect to the second electrode. By applying the binary waveform of (V), the second electrode 1
The charge discharged in the second opposed discharge space between the fifth electrode and the third electrode 16 causes a discharge in the first opposed discharge space between the first electrode 14 and the third electrode 16 via the third electrode. As a result, the first
Negative charges on the surface of the protective film 6 on the electrode 14 and the second electrode 15
Some of the positive charges on the surface of the upper protective film 6 are erased.

While the ramp voltage is being applied, a discharge current continuously flows, and a voltage for maintaining a discharge in the first opposed discharge space between the first electrode 14 and the third electrode 16 (hereinafter referred to as a discharge maintaining voltage). ) A voltage of about Va (V) is constantly applied.
Therefore, at the end of the initialization period, the difference between the applied voltage and the wall voltage is the discharge sustaining voltage V in the discharge space.
a (V).

In the writing period, a bias voltage Vs (V) is applied to the first electrode 14 so that discharge occurs only in the selected discharge cell. The selection of the discharge cell is performed by sequentially applying a negative pulse to the first electrode 14. If there is display data, the positive electrode data pulse voltage Vw is applied to the third electrode 16 while the first electrode 14 is being scanned.
(V) is applied. As a result, at time t1, a voltage Va (V) + Vw (V) is applied to the first opposed discharge space between the first electrode 14 and the third electrode 16, and the first opposed discharge space is applied with a relatively small voltage Vw (V). Discharge starts in the discharge space.

In the writing period, since a positive voltage is applied to the second electrode 15 with respect to the first electrode 14, the above-mentioned discharge generated in the first opposing discharge space is
5, at time t2, the second electrode 15 and the third
A discharge is also formed in the second opposed discharge space between the electrode 16 and the electrode 16. As a result, the polarity of the charge stored in the protection film 6 on the first electrode 14 is opposite to the polarity of the charge stored in the protection film 6 on the second electrode 15.

When there is no display data, no discharge occurs in the first opposed discharge space, and the electric charge accumulated in the protective film 6 on the first electrode 14 and the second electrode 15 is substantially equal to the initialization period. Retained at the end.

In the sustain period, the first electrode 14 and the second electrode 15
, A sustain pulse having an amplitude Vm (V) is applied alternately. The sustain pulse is applied with a phase such that a discharge with the second electrode 15 as the cathode side starts in the second opposed discharge space at time t3. At this time, since a positive voltage is applied to the first electrode 14 with respect to the second electrode 15, the discharge generated in the second opposed discharge space extends in the direction of the first electrode 14, At t4, a discharge is also formed in the first opposed discharge space. As a result, the polarity of the charge stored in the protective film 6 on the first electrode 14 and the second electrode 15 is reversed.

In the subsequent sustain period, the above operations are alternately repeated, and discharge light emission is performed a number of times corresponding to the weight of the subfield.

Next, regarding a mechanism in which a discharge started in one opposed discharge space extends in the direction of the other opposed discharge space,
The maintenance period will be described in detail with reference to FIGS. FIGS. 7 and 8 show the states of the applied voltage, wall charges, and discharge plasma during the sustain period in a simplified cross-sectional view of the panel of the present embodiment shown in FIG. That is, the protective film 6 is omitted.

FIG. 7A shows a sustain period time t3 (FIG. 6).
2) shows the wall charges and the applied voltage. At time t3, the second electrode 15 is grounded. In the writing period, since the negative wall charges are accumulated on the dielectric layer 5 on the second electrode 15, the second electrode 1 is located in the second opposed discharge space.
A voltage with 5 as the negative electrode is applied, and discharge starts. Positive wall charges are accumulated on the phosphor layer 11 on the third electrode 16. This is because during the writing period the second electrode 15
This is because the third electrode 16 having a low potential attracted positive charges while a large positive voltage was applied to the third electrode 16.

FIG. 7B shows a state in which discharge has started in the second opposed discharge space. When the discharge starts in the second opposed discharge space, a large amount of positive charges and negative charges are generated, and are attracted toward the second electrode 15 and the third electrode 16, respectively, to form wall charges. The wall voltage generated by the wall charge acts to cancel the voltage applied to the second opposed discharge space and stop the discharge. When the dielectric layer 5 on the second electrode 15 and the phosphor layer 11 on the third electrode 16 are compared, the latter has a smaller dielectric constant, so that the accumulation of wall charges proceeds faster on the third electrode 16 side. .
As a result, the anode end of the discharge moves in search of the phosphor surface into which negative charges can flow. The moving direction is the direction of the first electrode 14 where the positive wall charges are stored.

FIG. 7C shows a state in which the anode end of the discharge is moving. The anode end of the discharge extends toward the first electrode 14 while canceling out the positive charges accumulated on the phosphor layer 11.

FIG. 8A shows a state in which the anode end of the discharge has reached the first electrode 14 at time t4 (see FIG. 6). At this time, a so-called positive column is formed so as to connect the first opposed discharge space to the second opposed discharge space, and a large amount of ultraviolet rays is emitted. By this time, the potential of the first electrode 14 has risen to the external sustain voltage Vm (V), and a relatively strong discharge starts in the first opposed discharge space. The time from the occurrence of discharge in the second opposed discharge space until the anode end reaches the first electrode 14 is several hundred ns.

FIG. 8B shows a state immediately before the discharge stops. Due to the discharge generated in the first opposed discharge space, the first
A negative wall charge is formed on the dielectric layer 5 on the electrode 14, and a positive wall charge is formed on the phosphor layer 11 on the third electrode 16. Thus, the occurrence of the sustain discharge is stored as the wall charge in the first opposed discharge space.

FIG. 8C shows a state where the discharge is stopped as a result of accumulation of wall charges on the dielectric layer 5 and the phosphor layer 11. Negative charges are accumulated in the dielectric layer 5 on the first electrode 14 to which the positive external sustain voltage Vm (V) is applied, and positive charges are accumulated in the dielectric layer 5 and the phosphor layer 11 on the second electrode 15. Has been accumulated. This is obtained by reversing the wall charge distribution at time t3 for the first electrode 14 and the second electrode 15.

Therefore, in the state shown in FIG. 8C, when a positive external sustain voltage Vm (V) is applied to the second electrode 15 and the first electrode 14 is grounded, the first electrode 14 and the second electrode 15 The electrode 15 and the electrode 15 are replaced, and the same sustain discharge can be repeated.

Here, the previous discharge state is stored as wall charges in the opposed discharge space on the side where the anode end of the discharge has reached. For example, if a certain discharge reaches the second opposed discharge space and ends, the next discharge starts in the second opposed discharge space and is completed by reaching the first opposed discharge space. At the end of the discharge, the wall voltage of the opposed discharge space on the side where the discharge has started is almost completely erased as shown in FIG. 7A or 8C, and the previous discharge state is not stored.

In the above description, at t = t3, the external sustain voltage of the second electrode 15 reaches the ground voltage, and t = t3.
4, the description has been given on the assumption that the external sustain voltage of the first electrode 14 reaches Vm (V). However, the time interval has a considerable margin, and after the external sustain voltage of the second electrode 15 reaches the ground voltage, the external sustain voltage of the first electrode 14 becomes Vm.
The time Δt until reaching (V) may be any value as long as it is about 500 ns or less.

The fact that the operation of the last part of the sustain period and the operation of the initialization period of the second subfield in FIG. 4 are performed at the same time is the focus of the present invention. 6 will be described in detail below.

In describing the driving waveform of the present invention with reference to FIG. 1 and FIGS. 4 to 6, in order to facilitate comparison with the conventional driving waveform shown in FIG. One electrode 14
, Scan electrodes SCN1 to SCNn, second electrode 15 is sustain electrode SUS1 to SUSn, and third electrode 16 is data electrode D1.
ＤDm. Further, the discharge cell 1 shown in FIG.
8 is provided in a region as shown in FIG.

As shown in FIG. 4, the last part of the sustain period of the first sub-field overlaps the first half of the initialization period of the second sub-field. A positive pulse voltage Vr (V) is applied to SCN1 to SCNn, and all sustain electrodes SUS1 to SU
A positive pulse voltage of (Vr-Vm) (V) is applied to Sn. Subsequently, in the second half of the setup period of the second subfield, a positive voltage Vh (V) is applied to all the sustain electrodes SUS1 to SUSn, and all the scan electrodes SCN1 to SCN are applied.
A ramp voltage gradually falling from the voltage Vq (V) toward 0 (V) is applied to CNn.

In the above operation, focusing on the operation of the last part of the sustain period of the first subfield, all the scan electrodes SCN1 to SCNn and all the sustain electrodes SUS1 to SUS
The voltage between USn is Vr− (Vr−Vm) = Vm
(V), and the relationship between all the scan electrodes SCN1 to SCNn and all the sustain electrodes SUS1 to SUSn indicates that all the sustain electrodes SUS1 to SUSn are set to 0 as in the operation before the last part of the sustain period. (V) and all scanning electrodes S
This is equivalent to a case where a positive sustain pulse voltage Vm (V) is applied to CN1 to SCNn. Therefore, the scan electrode SCNi (i
Is an integer of 1 to n). The voltage between the surface of the protective film 6 on the upper surface and the surface of the protective film 6 on the sustain electrode SUSi is changed to the sustain pulse voltage Vm (V) by the scan electrode in the discharge cell 18. The positive wall charges accumulated on the surface of the protective film 6 on SCNi and the negative wall charges accumulated on the surface of the protective film 6 on the sustain electrode SUSi are added, and the panel of the present invention that performs the opposing sustain discharge is obtained. Exceeds voltage Vfss for starting sustain discharge. For this reason, the discharge cell 18 that has caused the write discharge
, A facing sustain discharge is generated between scan electrode SCNi and sustain electrode SUSi via data electrode Dj, and a negative wall voltage is accumulated on the surface of protective film 6 on scan electrode SCNi in discharge cell 18 and sustain electrode A positive wall voltage is accumulated on the surface of the protective film 6 on SUSi, and the final maintenance operation is performed. Such a sustain discharge does not occur in a discharge cell in which no writing is performed.

Next, focusing on the initializing period of the second subfield, in the initializing operation in the first half of the initializing period, all the scan electrodes SCN1 to SCNn and all the data electrodes D1 to Dm are connected. The voltage becomes Vr (V), and all the scan electrodes SCN1 to SCNn and all the sustain electrodes SU
The voltage between S1 and SUSn is Vm (V). In the discharge cell in which the write discharge has occurred, the data electrode Dj (j
Is an integer of 1 to n). The voltage between the surface of the phosphor layer 11 on the upper surface and the surface of the protective film 6 on the scan electrode SCNi is Vr (V).
The negative wall voltage accumulated during the write operation on the surface of the phosphor layer 11 on the data electrode Dj is subtracted from the sum of the positive wall charge accumulated on the surface of the protective film 6 on the scan electrode SCNi and the positive wall charge accumulated on the data electrode Dj. That is, the sum is obtained by adding the absolute value, and exceeds the discharge starting voltage. Therefore, in the discharge cell in which the write discharge has occurred, a counter discharge occurs between the scan electrode SCNi and the data electrode Dj, and the charge generated by this discharge passes through the phosphor layer 11 on the data electrode Dj,
A counter discharge occurs between the scan electrodes SUS1 to SUSn and the data electrode Dj, and this is the first initialization discharge,
A negative wall voltage is accumulated on the surface of the protective film 6 on the scan electrode SCNi, and a positive wall voltage is accumulated on the surface of the phosphor layer 11 on the data electrode Dj and the surface of the protective film 6 on the sustain electrode SUSi. You. However, the first initializing discharge is not weak, but rather a strong discharge.

On the other hand, in a discharge cell in which no write discharge has been performed, the voltage of the surface of the phosphor layer 11 on the data electrode Dj and the surface of the protective film 6 on the scan electrode SCNi are Vr.
From the sum of (V) and the positive wall voltage accumulated on the surface of the protective film 6 on the scan electrode SCNi, the data electrode Dj
The value obtained by subtracting the positive wall voltage accumulated on the surface of the upper phosphor layer 11 does not exceed the discharge starting voltage. For this reason, the first setup discharge does not occur in the discharge cells in which no writing has been performed in the first subfield.

Furthermore, the initializing operation in the latter half of the initializing period is the same as the operation in the latter half of the initializing period in the first subfield, and all the sustain electrodes SUS1 to SUSn
And a positive voltage Vh (V) is applied to all the scan electrodes SCN1.
To SCNn, a ramp voltage is applied to all the sustain electrodes SUS1 to SUSn from a voltage Vq (V) which is lower than the discharge start voltage to 0 (V) which is higher than the discharge start voltage. While the ramp voltage is falling, in the discharge cell 18 where the first setup discharge has occurred, the second weak setup discharge occurs from the sustain electrode SUSi to the scan electrode SCNi, and the protection film 6 on the scan electrode SCNi Wall voltage and sustain electrode SU accumulated on the surface of
Positive wall voltage accumulated on the surface of Si is weakened. On the other hand, the positive wall voltage on the surface of the phosphor layer 11 on the data electrode Dj is kept as it is. Regarding the discharge cells in which the first setup discharge has not occurred, the scan electrode SCNi is operated by the latter half of the setup period in the first subfield.
Since the wall voltage on the surface of the protective film 6 on the sustain electrode SUSi has already been weakened, the above-described second setup discharge does not occur.

As can be understood from the above description, the initialization operation in the second half of the initialization period in the second subfield is as follows.
Immediately after the end of the last sustain discharge of the first subfield, the discharge is performed immediately after the discharge cell 18 performing display.
Sustain electrodes SUS1 to SU via data electrodes D1 to Dm
The generation of a weak initializing discharge from Sn to scan electrodes SCN1 to SCNn causes the negative wall voltage accumulated on the surface of protective film 6 on scan electrodes SCN1 to SCNn and the reduction of protective film 6 on sustain electrodes SUS1 to SUSn. Since the positive wall voltage accumulated on the surface is weakened, the erasing operation of the sustain discharge is performed, and there is no need to provide an erasing period.

At this time, in the discharge cells displayed in the first sub-field, the first initializing discharge by the initializing operation in the first half of the initializing period in the second sub-field is not weak, and is not weak. The luminance due to the initializing discharge is considerably higher than the luminance of the second weak initializing discharge due to the initializing operation in the latter half of the initializing period. However, since the second initializing discharge is performed only in the discharge cell 18 to be displayed, the luminance of the initializing discharge in the second subfield is only added to the luminance of the sustaining discharge.

For a discharge cell in which no display is performed, an initializing discharge occurs during the initializing period of the first subfield, but a write discharge, a sustain discharge and an erase discharge are not performed, and the discharge cell corresponds to that discharge cell. Scan electrodes SCN1 to SCN
CNn and the wall voltage of the surface of the protective film 6 on the sustain electrodes SUS1 to SUSn and the phosphor layer 1 on the data electrodes D1 to Dm
The wall voltage on the surface of the first subfield is maintained at the end of the initialization period of the first subfield.

As is apparent from the above description, although the erasing period is not provided in the second to seventh subfields, the writing operation, the sustaining operation, the erasing operation and the initialization operation of the next subfield are surely performed. Done in Also,
In each of the sub-fields after the second sub-field, the reset discharge, the write discharge, the sustain discharge, and the erase discharge are not performed for the discharge cells that are not displayed, and the scan electrodes SCN1 to SCN corresponding to the discharge cells are not performed.
n and the wall voltage on the surface of the protective film 6 on the sustain electrodes SUS1 to SUSn and the wall voltage on the surface of the phosphor layer 11 of the data electrodes D1 to Dm are at the end of the initialization period of the subfield before each subfield. Will be kept as is.

For the eighth subfield,
By providing the single sustain period described in the first subfield, the sustain operation using the opposing discharge via the data electrodes D1 to Dm is performed. By providing the same erase period as in the conventional example, the erase operation is continued. Is performed. That is, the operation from the sustain period and the erase period of the eighth subfield shown in FIG. 4 to the initialization period of the next first subfield is the same as the operation shown in the conventional example.

As described above, in the embodiment of the present invention shown in FIG. 4, the weak initializing discharge in the initializing period in the first subfield is performed regardless of the presence or absence of the light emission display. In the subfields subsequent to the second subfield, the initializing discharge in the initializing period is performed as an initializing operation for the next subfield only for discharge cells for performing light emission display, and the luminance of the discharge is Only adds to the luminance of the sustain discharge, and such an initializing discharge does not occur in a discharge cell that does not display.

For example, in a 42-inch AC type plasma display panel having a matrix configuration of 480 rows and 852 × 3 columns, when one field period is constituted by eight sub-fields and 256 gradations are displayed, the maximum is obtained. The luminance was 420 cd / m ² , whereas the luminance due to ^two setup discharges in the setup period of the first subfield was 0.15 cd / m ² . Here, Vp = V
q = Vm = 220V, Vr = 400V, Vs = 70V,
Vh = 240V and Vn = −200V.

As a result, in the present embodiment, in the display of a so-called black screen in which there are no discharge cells to be displayed on the panel, only the light emission of the initializing discharge in the first subfield is performed. Has a luminance of 0.15 cd / m ²
When the panel is displayed in a dimly lit place, the visibility of black display is significantly improved as compared with the conventional case. Further, the contrast of the panel according to the present embodiment is 420
/0.15:1=2800:1, and an extremely high value of contrast was obtained.

As described above, in the panel of the present embodiment, the distance dss between the first electrode 14 and the second electrode 15
Discharge is first started in the opposed discharge space having a shorter discharge space height dsa, and is extended to the other opposed discharge space. That is, since the positive column discharge in the extended discharge space can be used while starting the discharge at a relatively low voltage, the luminous efficiency can be improved without increasing the discharge voltage. As a result, in the panel of the present embodiment, a high luminous efficiency of 2 lm / W or more can be obtained, and the luminous efficiency of the conventional panel is 1 lm / W or less. More than doubled.

Further, in the driving method of the present embodiment, in addition to being able to improve the luminous efficiency without increasing the discharge voltage, the operation of maintaining the final part of the sustain period and the operation of initializing the next subfield are not required. Is performed at the same time, the display brightness of a so-called black screen without any light emission display is only the light emission brightness of the initializing discharge of the first sub-field. A driving method can be obtained.

In the above embodiment, the voltage Vr applied during the initialization period of the first subfield is
Although the case where (V) and the voltage Vr (V) applied in the initialization period of the second to eighth subfields have the same value has been described, different values may be used.

In the above-described embodiment, a method of driving an AC type plasma display panel in which one field period is constituted by eight subfields having an initialization period, a writing period, and a sustaining period to perform gradation display. Of the eight subfields, the driving method for simultaneously performing the sustaining operation of the last part of the sustaining period and the initializing operation of the initializing period of the next subfield for seven subfields has been described. The number of subfields constituting a field period, the number of subfields without an erasing period, and the number of subfields in which the sustaining operation of the last part of the sustaining period and the initializing operation of the next subfield are simultaneously performed The number is not limited.

The applied voltage waveforms in the initialization period and the writing period do not need to be the same as those in this embodiment, and may be any as long as wall charges are selectively formed according to the presence or absence of light emission display.

Further, in the conventional example and the present embodiment, in order to make a comparison with emphasis on the difference in the electrode structure, the explanation has been made using the panel in which the data electrode is covered with the phosphor layer. The driving method of the panel and the plasma display panel is not limited to this configuration, but may be a panel configuration in which the data electrode is covered with a dielectric layer and a phosphor layer is formed thereon.

Further, the driving method of the present invention employs A
Similar effects can be obtained even when the present invention is applied to a C-type plasma display panel.

[0079]

As described below, according to the present invention, the first substrate in which the first electrode and the second electrode covered with the dielectric layer are formed in parallel with each other, and the third electrode is orthogonal to the first electrode. Provided is an AC-type plasma display panel having improved luminous efficiency without drastically increasing a discharge voltage, and a method for driving the same, since a second substrate formed in the direction is opposed to a second substrate across a discharge space. be able to.

Further, as described below, the present invention provides a final sustaining operation of a sustaining period in at least one of a plurality of subfields constituting one field and an initial operation of a subfield following the subfield. By performing the initialization operation of the initialization period at the same time, the luminance in the so-called black screen display without emission display, the emission of the initialization discharge of one subfield of a plurality of subfields constituting one field Since only the luminance is obtained and the visibility of black is greatly improved, it is possible to provide a method of driving an AC plasma display panel in which the contrast of the panel is greatly enhanced.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a panel according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line CC of FIG. 1;

FIG. 3 is a sectional view taken along the line DD of FIG. 1;

FIG. 4 is an operation drive timing chart showing a panel driving method according to one embodiment of the present invention.

FIG. 5 is an electrode array diagram of a panel according to an embodiment of the present invention.

FIG. 6 is a diagram showing a voltage waveform applied to a panel according to an embodiment of the present invention.

FIG. 7 is a view for explaining the behavior of wall charges in the panel of one embodiment of the present invention.

FIG. 8 is a view for explaining the behavior of wall charges in the panel of one embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a conventional panel.

FIG. 10 is a diagram showing an applied voltage waveform of a conventional panel.

FIG. 11 is an operation drive timing chart showing a conventional panel driving method.

FIG. 12 is a diagram showing an electrode arrangement of a conventional panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 12 Panel 2, 2a Discharge space 3 Front substrate 4 Back substrate 5 Dielectric layer 6 Protective film 7 Scan electrode 8 Sustain electrode 9 Data electrode 10 Partition 11 Phosphor layer 14 First electrode 15 Second electrode 16 Third electrode 17 Discharge pixel 18 Discharge cell

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G09G 3/288 G09G 3/28 EB (72) Inventor Takao Wakiya 1006 Kazuma Kazuma, Kadoma City, Osaka Matsushita Electric F-term (reference) in Sangyo Co., Ltd. 5C040 FA01 FA04 GB03 GB14 GC11 LA10 LA14 LA18 MA02 MA04 MA14 5C080 AA05 BB05 DD01 DD26 EE19 EE29 HH02 HH04 HH06 HH07 JJ04 JJ06

Claims (7)

[Claims] 1. A first substrate in which a first electrode and a second electrode covered with a dielectric layer are formed in parallel with each other, and a second substrate in which a third electrode is formed in a direction orthogonal to the first electrode. An AC-type plasma display panel in which a substrate is disposed to face a discharge space, and a distance between the first electrode and the second electrode is set to be greater than a height of the discharge space. 2. A discharge space between the first electrode and the third electrode is a first opposed discharge space, and a discharge space between the second electrode and the third electrode is a second opposed discharge space. When the discharge in the second opposed discharge space is extended to the first opposed discharge space along the third electrode, the discharge in the first opposed discharge space is extended to the second opposed discharge space along the third electrode. 2. The AC-type plasma display panel according to claim 1, having a function of performing a sustain discharge by extending the discharge space into a discharge space. 3. A gradation display is performed by forming one field period by a plurality of subfields having an initialization period, a writing period, and a sustain period, and performing a grayscale display in at least one of the plurality of subfields. A method for driving an AC plasma display panel, wherein a final sustaining operation and an initializing operation in an initializing period of a subfield subsequent to the at least one subfield are performed simultaneously. 4. An erasing operation for performing a second initializing operation after a first initializing operation which is an initializing operation of the initializing period, and stopping a sustain discharge simultaneously with the second initializing operation. A method for driving an AC-type plasma display panel, comprising a sub-field for performing the following. 5. During the initialization period, a voltage exceeding a discharge starting voltage is applied between the third electrode and the first electrode, and at the same time, a discharge is generated between the second electrode and the first electrode. A method for driving an AC-type plasma display panel, characterized by applying a sustain voltage for maintaining. 6. In the initialization period, a positive voltage is applied to the second electrode, and a voltage is applied to the first electrode from a voltage lower than the discharge start voltage to the second electrode to a voltage higher than the discharge start voltage. A method for driving an AC-type plasma display panel, characterized by applying a ramp voltage that changes toward the same. 7. In the initialization period, a binary voltage is applied to the second electrode, and the first electrode exceeds a discharge start voltage from a voltage lower than or equal to a discharge start voltage with respect to the third electrode. A method for driving an AC plasma display panel, characterized by applying a ramp voltage that changes toward a voltage.