JP2001093424A - Ac type plasma display panel and drive method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC type plasma display panel which shows high luminous efficiency without greatly increasing applied voltage for the purpose of write-in of data to be displayed and for maintaining discharge even when a space between electrodes is made long, and to provide a driving method of the AC type plasma display panel. SOLUTION: A front board 3 faces a rear board 4 with an emission space 2a therebetween. A plurality of pairs of electrodes formed of band-shaped first electrodes 13 and band-shaped second electrodes 14 are arranged on the front board 3, wherein the pairs of electrodes are covered with a dielectric layer 5 and a protection layer 6. A plurality of band-shaped third electrodes 15 and a partition 10 are arranged on the rear board 4 in such a direction that the band-shaped third electrodes 15 and a partition 10 cross the first electrodes 13 and the second electrodes 14 at right angles. A luminescent layer 11 is formed from the third electrodes 15 to a side of the partition 10. Voltage having a waveform with a slowly changing ramp is applied to the first electrodes, the second electrodes, or the third electrodes at an initialization period prior to an address period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an AC plasma display panel and a method of driving the same.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view of a main part of a conventional AC surface discharge type plasma display panel. FIG. 6B shows FIG.
It is an AA sectional view of (a).

As shown in FIG. 6, a conventional AC surface discharge type plasma display panel (hereinafter referred to as a conventional panel) 1 has a glass front substrate 3 and a glass rear substrate 4 sandwiching a discharge space 2 therebetween. They are arranged facing each other. On the front substrate 3, an electrode group including a pair of strip-shaped scan electrodes 7 and sustain electrodes 8 covered with a dielectric layer 5 and a protective layer 6 is arranged in parallel with each other. The scanning electrode 7 and the sustaining electrode 8 are composed of transparent electrodes 7a, 8a and metal busbars 7b, 8b for increasing conductivity, respectively.

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. A phosphor layer 11 is provided between the adjacent partitions 10 so as to cover the data electrodes 9. 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.

[0006]

However, the conventional panel has a problem that the luminous efficiency is significantly lower than that of a display device such as a CRT. For example, the distance (sustain discharge gap) dp between scan electrode 7 and sustain electrode 8 is 80 to 10
In a conventional panel of 0 μm, the luminous efficiency is 1 lm / W or less, which is about one fifth of the CRT.

In general, it is known that the luminous efficiency increases when the distance between the electrodes causing discharge is increased.
When the sustain discharge gap dp is increased, the discharge starting voltage Vf _SS
However, there is a problem that the driving speed rises sharply according to the Paschen curve, making driving difficult.

The present invention has been made in order to solve such a problem. Even when the sustain discharge gap is lengthened, light emission can be performed without greatly increasing an applied voltage for writing display data and maintaining discharge. It is an object of the present invention to provide an AC plasma display panel with high efficiency and a driving method thereof.

[0009]

According to the present invention, there is provided an AC-type plasma display panel comprising a first dielectric layer covered by a first dielectric layer.
A substrate on which an electrode and a second electrode are formed parallel to each other;
A third electrode covered with a second dielectric layer is disposed so as to face another substrate formed in a direction crossing the first electrode with a discharge space interposed therebetween, and the first electrode, the second electrode, Is set larger than the height of the discharge space,
A function of gently changing the potential of the first electrode, the second electrode or the third electrode to perform an initialization discharge, and a function of discharging a discharge between the first electrode or the second electrode and the third electrode. When activated, it has a function of inducing a discharge between the first electrode and the second electrode.

With this configuration, a discharge is generated between the first electrode, the second electrode, and the third electrode having a large distance between the electrodes without greatly increasing a voltage required for writing display data and maintaining a discharge. be able to.

Further, the method of driving an AC type plasma display panel according to the present invention provides a method of driving an AC type plasma display panel, comprising the steps of:
A substrate on which an electrode and a second electrode are formed parallel to each other;
A third electrode covered with a second dielectric layer is disposed so as to face another substrate formed in a direction crossing the first electrode with a discharge space interposed therebetween, and the first electrode, the second electrode, Is a method of driving an AC-type plasma display panel in which the distance is set to be greater than the height of the discharge space,
In the initialization period, a voltage waveform having a gradually changing slope is applied to the first electrode, the second electrode, or the third electrode.
Applied to an electrode, and in a sustain period, a voltage higher than a discharge starting voltage between the first electrode and the third electrode when the first electrode is a cathode, and a voltage between the first electrode and the third electrode. When a discharge exists between the first electrode and the second electrode, a sustain pulse voltage having an amplitude set to be larger than 1/2 of a discharge starting voltage between the first electrode and the second electrode is applied to the first electrode and the second electrode. The voltage is alternately applied to the second electrode.

According to this method, the first electrode having a large inter-electrode distance is used.
A stable discharge can be generated between the electrode and the second and third electrodes.

[0013]

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

FIGS. 1 to 3 show an AC type plasma display panel (hereinafter referred to as a panel) according to a first embodiment of the present invention.
Shown in FIG. 2 is a sectional view taken along line BB of FIG. 1, and FIG.
It is CC sectional drawing of.

As shown in FIGS. 1 to 3, the panel 12 according to the first 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. Have been. On the front substrate 3, a plurality of electrode pairs each including a strip-shaped first electrode 13 and a second electrode 14 covered with a first dielectric layer including a dielectric layer 5 and a protective layer 6 are arranged. As the protective layer 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 electrodes 13 and the second electrodes 14.
5 are arranged, and a strip-shaped partition wall 10 for isolating each third electrode 15 and forming a discharge space 2a is formed as a third partition.
It is provided between the electrodes 15. In addition, a phosphor layer 11 as a second dielectric layer is formed from the third electrode 15 to the side surface of the partition 10. Further, helium (He), neon (Ne), and argon (A) are provided in the discharge space 2a.
r), a mixed gas of at least one of them and xenon (Xe) is sealed. One first electrode 13 and 1
1 at the intersection of one second electrode 14 and one third electrode 15
One discharge cell is formed. Then, red, green and blue phosphor layers 11 are respectively formed, and one pixel 16 is constituted by three discharge cells adjacent to each other.

The panel 12 is configured to view an image display from the front surface substrate 3 side which is the display surface side, and the discharge space 2
a, the fluorescent layer 1
1 is excited, and visible light generated from the phosphor layer 11 is used for display light emission.

In the panel of the present embodiment, the first electrode
13 and the distance between the second electrode 14 and d_SSAnd the third electrode 15
Of the surface of the phosphor layer 11 and the protective layer 6 on the center line of FIG.
Distance from the surface, that is, the height of the discharge space 2a is d_SAMade
Then d_SS> D_SAIs set. Here, the discharge between each electrode
The charge start voltage is defined as follows. Vf_SS: Start of discharge between first electrode 13 and second electrode 14
Voltage Vf_SA: Using the first electrode 13 (or the second electrode 14) as a cathode
The first electrode 13 (or the second electrode 14) and the third
Discharge starting voltage Vf between electrode 15_AS: The first electrode 13 when the third electrode 15 is a cathode
(Or the discharge between the second electrode 14 and the third electrode 15)
Starting voltage Vf_SSA: First electrode 13 (or second electrode 14) and third electrode 13
The first electrode 1 when a discharge exists between the first electrode 1 and the electrode 15
Discharge start voltage between the third electrode 14 and the second electrode 14 Here, the discharge start voltage Vf_SSIs a conventional panel,
The same as the firing voltage between scan electrode 7 and sustain electrode 8
However, in the present embodiment, the first electrode 13 and the second electrode 14
The distance to the conventional panel
Greater than the firing voltage between scan electrode 7 and sustain electrode 8
Value. Discharge starting voltage Vf_SAAnd the discharge starting voltage Vf_AS
Is the discharge starting voltage when the discharge polarity is opposite to each other
Is Vf _SAIndicates the protective layer 6 having a high secondary electron emission coefficient on the cathode side.
Vf_ASIs
Fluorescence whose secondary electron emission coefficient is considerably lower than that of the protective layer 6
This is the firing voltage when the body layer 11 is on the cathode side.
Vf_SA≪Vf_ASThere is a relationship. Also, the first electrode 13
Between the third electrode 15 or the second electrode 14 and the third electrode
If a discharge has occurred beforehand between
There is a large amount of charge in the discharge space where electricity is occurring
The firing voltage between the first electrode 13 and the second electrode 14
Decreases and Vf_SSA≪Vf_SSBecomes

Next, a method of displaying image data on the panel 12 of the present embodiment will be described.

In the panel 12 of the present embodiment, one field period is divided into a plurality of subfields having a weight of a light emission period based on a binary system, and gradation display is performed by a combination of subfields to emit light. Each subfield includes an initialization period, an address period, and a sustain period.

In order to display image data, different signal waveforms are applied to the electrodes during the initialization period, the address period, and the sustain period. The driving signal waveform of the panel will be described with reference to FIGS.

FIG. 4A shows a voltage waveform Vx applied to the first electrode 13, FIG. 4B shows a voltage waveform Vy applied to the second electrode 14, and FIG. FIG. 4D shows a voltage waveform Va applied to the reference numeral 15, and FIG.

In FIG. 5A, the solid line is the third electrode 15
5 shows a voltage waveform Vx-Va of the first electrode 13 as viewed from the side. The broken line indicates the wall voltage between the first electrode 13 and the third electrode 15, and the wall voltage accumulated in the protective layer 6 on the first electrode 13 and the phosphor layer 11 on the third electrode 15. Is the sum with the wall voltage stored in In FIG. 5B, the solid line indicates the voltage waveform Vy-V of the second electrode 14 as viewed from the third electrode 15.
a. The broken line represents the wall voltage between the second electrode 14 and the third electrode 15, and the wall voltage accumulated in the protective layer 6 on the second electrode 14 and the phosphor layer 11 on the third electrode 15. Is the sum with the wall voltage stored in In FIG. 5C, the solid line represents the voltage waveform Vx-Vy of the first electrode 13 as viewed from the second electrode 14 by a solid line. The broken line indicates the wall voltage between the second electrode 14 and the first electrode 13, and the wall voltage accumulated in the protection layer 6 on the second electrode 14 and the wall voltage between the second electrode 14 and the first electrode 13. Is the sum with the wall voltage stored in

These wall voltages are generated by wall charges accumulated on the protective layer 6 or the phosphor layer 11 according to the generated discharge. The polarity of the wall voltage is set such that the difference between the applied voltage and the wall voltage represents the voltage applied to the discharge space between the respective electrodes. FIG. 5A,
The polarity of the wall charges accumulated in the protective layer 6 on the first electrode 13 is shown on the broken line in FIG. 5C, and is stored in the protective layer 6 on the second electrode 14 on the broken line in FIG. The polarity of the wall charge is indicated.

Next, the behavior of the applied voltage waveform and the wall voltage in each period of the operation will be described. In the first half of the initialization period, a ramp voltage that rises with respect to the third electrode 15 is applied to the first electrode 13 and the second electrode 14, and between the first electrode 13 and the third electrode 15 and between the first electrode 13 and the third electrode 15. Discharge occurs between the first electrode 14 and the third electrode 15. As a result, the first electrode 13 and the second
Negative charges are accumulated in the protective layer 6 on the electrode 14. In the latter half of the initialization period, a ramp voltage that falls with respect to the third electrode 15 is applied to the first electrode 13 so that the first electrode 13 and the third electrode 1
5 and discharge occurs. As a result, the negative charge on the surface of the protective layer 6 on the first electrode 13 is adjusted.

While the ramp voltage is being applied, a weak discharge continuously occurs, and a voltage of about the discharge starting voltage Vs is constantly applied to the discharge space. Therefore, when the initialization period ends, the difference between the applied voltage and the wall voltage is substantially equal to the discharge starting voltage Vs in the discharge space. In FIG. 5, these voltages are represented as Vs _xa and Vs _ya , respectively.

In the address period, all the first electrodes 13
Are sequentially scanned by applying a negative scanning pulse. If there is display data, a positive data pulse voltage Va is applied to the third electrode 15 while scanning the first electrode 13. Thus, at time t ₁ , the discharge space between the first electrode 13 and the third electrode 15 is Vs _xa + Va
Is applied, and a write discharge starts. Here, in the discharge space between the first electrode 13 and the third electrode 15, a wall voltage Vs _xa substantially equal to the discharge starting voltage is applied.
Discharge can be started with a slight voltage Va.

The first electrode 13 and the third electrode 13
When a discharge occurs between the first electrode 13 and the electrode 15, a voltage of about the bias voltage Vyb of the second electrode 14 is applied.
A discharge is induced between the first electrode 14 and the second electrode 14. The discharge becomes pulse discharge, discharge because it forms charged particles of a large amount of positive and negative in the space 2a, at time t _2, the surface of the protective layer 6 and the phosphor layer 11 wall so as to cancel the electric field applied to the discharge space 2a Charges are distributed. As a result, the discharge stops, and the polarity of the charge accumulated on the surface of the protective layer 6 on the first electrode 13 and the second electrode 14 is reversed.

As described above, in the address period, the initialization discharge is performed by the ramp voltage, so that wall charges corresponding to the presence or absence of display data can be formed at a low data pulse voltage Va.

Subsequently, in the sustain period, _VSUS pulses are alternately applied to the first electrode 13 and the second electrode 14. Where V
_SUS is set so as to satisfy the following relationship: Vf _SA <V _SUS <Vf _AS (1) Vf _SSA <2V _SUS <Vf _SS (2)

At the beginning of the sustaining period, at time t ₃ , _VSUS is applied in the direction of using the second electrode 14 as a cathode as shown in FIG. 5B. Discharge starts between the first electrode 15 and the third electrode 15. When the discharge starts between the second electrode 14 and the third electrode 15, the discharge lowers the discharge starting voltage between the second electrode 14 and the first electrode 13 to Vf _SSA (V). As shown in FIG.
The voltage applied to the discharge space between the electrode 13 and the second electrode 14 is 2 V _SUS or more, and the discharge starts between the first electrode 13 and the second electrode 14 according to Expression (2). As a result, the display light emission occurs because the wall voltage is formed so as to cancel the potential in the discharge space, the discharge at time t ₄ is stopped.

At time t ₅ , V _SUS is applied in the direction of using the first electrode 13 as a cathode as shown in FIG. 5A, so that the first electrode 13 and the third electrode 15 Discharge starts between the two. When a discharge is started between the first electrode 13 and the third electrode 15, the discharge lowers the discharge start voltage between the first electrode 13 and the second electrode 14 to Vf _SSA (V). 5C, the first electrode 13 and the second electrode 1
The voltage applied to the discharge space between the first electrode 13 and the second electrode 14 is 2 V _SUS , and the discharge starts between the first electrode 13 and the second electrode 14 according to Expression (2). As a result, the display light emission occurs because the wall voltage is formed so as to cancel the potential in the discharge space, the discharge at time t ₆ is stopped.

By repeating the above operation, it is possible to write the display data and maintain the display discharge at a relatively low voltage in the panel where the distance d _SS between the first electrode 13 and the second electrode 14 is large. it can.

Next, an example of the panel design parameters according to the present embodiment is shown in Table 1.

[0035]

[Table 1]

In this panel, each discharge starting voltage is as follows: Vf _SS = 700 V Vf _SA = 250 V Vf _AS = 350 V Vf _SSA = 450 V, and the gradient of the gradient voltage during the initialization period is 5 V / μs.
, And the address pulse voltage and the sustain pulse voltage were set to Va = 80 V and V _SUS = 250 V, respectively, whereby stable panel driving could be performed.

According to the results of experiments conducted by the present inventors on various panel design values, if the gradient of the ramp voltage during the initialization period is 10 V / μs or less, the effect shown in this embodiment is confirmed. Was. Also, a stable address operation can be obtained unless the lower limit of the gradient of the ramp voltage during the initialization period becomes 0. However, in the case of displaying 256 gradations, the time of one field is about 16 ms. The practical range of the gradient is 0.5 V / μ
s or more.

In the panel of the present embodiment, the distance d _SS between the first electrode 13 and the second electrode 14 is 400 μm, which is about 5 times larger than the sustain discharge gap (80 to 100 μm) of the conventional panel.
It is twice as large. For this reason, when the conventional driving method is used, the sustain voltage becomes very high, 350 V (= Vf _SS / 2) or more, and stable sustain discharge cannot be performed. In the panel of the present embodiment,
The ramp voltage is used as the initialization waveform, and the first electrode 1
By inducing a discharge between the first electrode 13 and the second electrode 14 by a discharge generated between the third electrode 15 and the third electrode 15 or between the second electrode 14 and the third electrode 15, a voltage is generated. Stable address discharge and sustain discharge can be performed without greatly increasing.

As a result, in the panel of this embodiment, 2 l
A luminous efficiency of m / W was obtained. Since the luminous efficiency of the conventional panel is 1 lm / W or less, the luminous efficiency of the panel of this embodiment is about twice as large as that of the conventional panel.

As described above, in the present embodiment, the distance between the first electrode and the second electrode can be increased, so that the luminous efficiency is high and the discharge voltage is suppressed from increasing.
A C-type plasma display panel and a driving method thereof can be obtained.

The applied voltage waveforms in the initialization period and the address period do not need to be the same as those in the present embodiment, and may be any as long as wall charges are selectively formed according to the presence or absence of image data.

[0042]

As described above, according to the present invention, in the AC type plasma display panel in which the distance between the first electrode and the second electrode is set to be larger than the height of the discharge space, the ramp voltage waveform is set during the initialization period. In addition to using the light emitting device, a discharge is generated between the first electrode and the second electrode by a discharge generated between the first electrode and the second electrode in the address period and the sustain period, so that light emission is performed without significantly increasing the sustain voltage. An AC-type plasma display panel with improved efficiency and a driving method thereof can be provided.

[Brief description of the drawings]

FIG. 1 is a cutaway 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 BB of FIG. 1;

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

FIG. 4 is a diagram showing a voltage waveform applied to a panel according to an embodiment of the present invention.

FIG. 5 is a diagram showing a voltage waveform between respective electrodes and a wall voltage waveform of the panel according to the embodiment of the present invention.

FIG. 6 is a plan view and a sectional view of a cutaway portion of a main part of a conventional panel.

[Explanation of symbols]

 2, 2a Discharge space 3 Front substrate 4 Back substrate 5 Dielectric layer 6 Protective layer 10 Partition wall 11 Phosphor layer 12 Panel 13 First electrode 14 Second electrode 15 Third electrode

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C040 FA01 FA04 GB03 GB14 GC11 LA18 MA12 5C080 AA05 BB05 DD03 DD30 EE29 FF12 GG12 HH02 HH04 HH05 JJ04 JJ06

Claims (7)

[Claims] 1. A substrate on which a first electrode and a second electrode covered by a first dielectric layer are formed in parallel with each other, and a third electrode covered by a second dielectric layer comprises the first electrode. And another substrate formed in a direction intersecting the discharge space is disposed facing the discharge space, the distance between the first electrode and the second electrode is set to be greater than the height of the discharge space, A function of performing an initializing discharge by gradually changing the potential of the first electrode, the second electrode or the third electrode, and causing a discharge between the first electrode or the second electrode and the third electrode An AC-type plasma display panel having a function of inducing a discharge between the first electrode and the second electrode. 2. A substrate in which a first electrode and a second electrode covered with a first dielectric layer are formed in parallel with each other, and a third electrode covered with a second dielectric layer is the first electrode. Another substrate formed in a direction intersecting the discharge space is disposed facing the discharge space, and the distance between the first electrode and the second electrode is set to be greater than the height of the discharge space. A method of driving a display panel, comprising: applying a voltage waveform having a gradually changing slope to the first electrode, the second electrode, or the third electrode during an initialization period; A case where a discharge starting voltage between the first electrode and the third electrode is larger than a case where one electrode is a cathode, and a discharge exists between the first electrode and the third electrode; Discharge initiation voltage between the first electrode and the second electrode A method for driving an AC-type plasma display panel, wherein a sustain pulse voltage having an amplitude set to be larger than 1/2 of the pressure is alternately applied to the first electrode and the second electrode. 3. An amplitude of said sustain pulse voltage is equal to said second pulse voltage.
When the discharge start voltage between the second electrode and the third electrode when the electrode is a cathode, and when a discharge is present between the second electrode and the third electrode, 3. The method of driving an AC type plasma display panel according to claim 2, wherein the discharge start voltage between the first electrode and the second electrode is set to be larger than 1/2. 4. An amplitude of the sustain pulse voltage is equal to the first
The discharge start voltage between an electrode and the second electrode is set to be smaller than 1/2 of the discharge start voltage.
A driving method of the AC-type plasma display panel described in the above. 5. The method according to claim 1, wherein said sustain pulse voltage has an amplitude of said third pulse voltage.
The AC plasma display panel according to any one of claims 2 to 4, wherein a discharge starting voltage between the first electrode and the third electrode when the electrode is a cathode is set to be smaller than the discharge starting voltage. Drive method. 6. The method according to claim 6, wherein an amplitude of said sustain pulse voltage is equal to said third pulse voltage.
The AC plasma display panel according to any one of claims 3 to 5, wherein a discharge starting voltage between the second electrode and the third electrode when the electrode is a cathode is set to be lower than the discharge start voltage. Drive method. 7. The voltage change rate of the inclined portion is 10 V / μs.
7. The method according to claim 2, wherein the following parts are provided.
The method for driving an AC plasma display panel according to any one of the above.