JP3578543B2 - Driving method of PDP - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving method of a matrix display type PDP (Plasma Display Panel) in which sustain electrodes are arranged so that surface discharge occurs.
[0002]
Among the AC-driven PDPs that use wall charges for selective light emission, surface-discharge PDPs, in particular, are suitable for color display using phosphors and have attracted attention as large-screen display devices for HDTV.
[0003]
[Prior art]
In a general surface discharge type PDP, a pair of sustain electrodes is arranged for each matrix display line, and the total number of sustain electrodes is 2n (n is the number of lines). Since each sustain electrode pair is independent for each line, line-sequential addressing can be easily performed. A display method of this type of PDP employs a driving method in which a line-sequential addressing operation and a sustain operation of applying an alternating voltage to a sustain electrode pair are performed in a time sharing manner.
[0004]
On the other hand, a surface discharge type PDP having a structure in which sustain electrodes are arranged at equal intervals and each sustain electrode is used for displaying two lines has been proposed (Japanese Patent Laid-Open No. 2-220330). The total number of the sustain electrodes is (n + 1). The electrode configuration of this PDP can increase the arrangement density of the sustain electrodes as compared with the above-mentioned general surface discharge type PDP, and is suitable for high definition and high brightness. The above publication discloses a driving method in which an addressing operation and a sustain operation are performed in parallel.
[0005]
[Problems to be solved by the invention]
According to the driving method employed in the above-described general surface discharge type PDP, the line scanning period can be set shorter than the sustain voltage application period, so that the time required for addressing for scanning several hundred lines is required. Can be shortened. The time required for addressing on the gray scale display should be as short as possible. Further, since there is no temporal shift in the sustain period of each line, the display quality of a moving image can be improved.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to realize addressing operation and sustaining operation in a time-division manner in a PDP having a structure in which a sustain electrode is shared for display of two adjacent lines, thereby achieving high-speed addressing. I have.
[0007]
[Means for Solving the Problems]
To avoid the influence of the previous screen, the accumulation state of the wall charges must be initialized prior to the addressing. When the sustain electrode pair is independent for each line, it is only necessary that the charging state of all the lines is uniform. Good. However, when the sustain electrode straddles two adjacent lines, line-sequential addressing cannot be performed if the charged state is uniform.
[0008]
The method according to the first aspect of the present invention is a method of driving a PDP configured to perform matrix display with n (n ≧ 4) lines by (n + 1) sustain electrodes extending in the line direction. A first operation of forming a charged state in which a wall charge of the first polarity exists on one side in the column direction within the unit light emitting region in the line and substantially no wall charge of the first polarity exists on the other side; The second operation of performing line-sequential addressing using wall charges of the first polarity and the third operation of simultaneously applying a sustain voltage to all lines are repeated.
[0009]
In the method according to the second aspect of the present invention, a value K obtained by counting the sustain electrodes from one end side in the arrangement direction satisfies a condition of (K = 1 + 4 M) , which is represented by a positive integer M including 0. When divided into a first group, a second group satisfying the condition (K = 2 + 4 M), a third group satisfying the condition (K = 3 + 4 M) , and a fourth group satisfying the condition (K = 4 + 4 M) Wherein the first operation causes a discharge between all the sustain electrodes, and causes a discharge between the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto. A second step; and a third step of causing a discharge between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto .
[0010]
4. The method according to claim 3, wherein the first operation causes a discharge between all the sustain electrodes, and the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto. A second step of generating a discharge between the first group of sustain electrodes and a third step of generating a discharge between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto; A fourth step of causing a discharge between the electrodes and the second group of sustain electrodes adjacent thereto and between the third group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto; Between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto, and between the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto. It is made of a fifth step of causing a discharge.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic diagram of an electrode configuration of a PDP 1 according to the present invention.
In the PDP 1, the sustain electrodes X and Y are alternately arranged in the column direction of the matrix display area SC, and the address electrodes A are arranged in the line direction. The total number of the sustain electrodes X and Y is a value obtained by adding 1 to the number n of lines. The arrangement interval of the sustain electrodes X and Y is set to a size of about several tens of μm capable of generating a surface discharge at a practical range of drive voltage (for example, 100 to 200 V). In practice, the width of the sustain electrodes X and Y is about 100 to 200 μm.
[0013]
Each of the sustain electrodes X and Y is an individual electrode to enable line-sequential scanning. Adjacent sustain electrodes X and Y constitute a sustain electrode pair, and correspond to one line L. That is, a total of (n-1) sustain electrodes X and Y excluding both ends of the array are used for displaying two lines L, respectively. The sustain electrodes X and Y at both ends are used for displaying one line L. In each line L, a surface discharge cell C is defined for each unit light emitting region (sub-pixel).
[0014]
FIG. 2 is a diagram showing the internal structure of the PDP 1. FIG. 2B is a cross-sectional view taken along the arrow b in FIG.
In the PDP 1, sustain electrodes X and Y are arranged on the inner surface of the glass substrate 11 on the front side. A dielectric layer 17 for AC driving is provided so as to cover the sustain electrodes X and Y with respect to the discharge space 30. A protective film 18 is deposited on the surface of the dielectric layer 17. Both the dielectric layer 17 and the protective film 18 have translucency. Each of the sustain electrodes X and Y is composed of a wide linear band-shaped transparent electrode 41 made of a transparent conductive film such as an ITO thin film and a narrow linear band-shaped bus electrode 42 made of a metal thin film. The bus electrode 42 is an auxiliary electrode for ensuring appropriate conductivity, and is arranged at the center of the transparent electrode 41 in the width direction (column direction). The partition wall 19 is provided on the dielectric layer 17 so as to overlap the bus electrode 42 in a plan view. The discharge space 30 is divided for each line L by each partition wall 19. On the other hand, on the inner surface of the glass substrate 21 on the back side, address electrodes A are arranged so as to be orthogonal to the sustain electrodes X and Y. Between the address electrodes A, one partition wall 29 having a linear shape in plan view is provided. The partitions 29 divide the discharge space 30 into sub-pixels in the line direction, and the gap between the discharge spaces 30 is defined by the contact between the partition 19 on the front side and the partition 29 on the back side. Then, phosphor layers 28 of three colors R, G and B for color display are provided so as to cover the wall surface on the back side including the upper part of the address electrode A and the side surface of the partition wall 29.
[0015]
One line of the matrix display corresponds to one side in the width direction of the sustain electrode X and the other side in the width direction of the sustain electrode Y, and one column corresponds to one address electrode A. Then, three columns correspond to one pixel (pixel) EG. That is, one pixel is composed of three sub-pixels of R, G, and B arranged in the line direction.
[0016]
The charge state of the dielectric layer 17 is controlled by the counter discharge between the address electrode A and the sustain electrodes X and Y. When a sustain pulse is alternately applied to the sustain electrodes X and Y, a surface discharge (main discharge) along the substrate surface occurs in the surface discharge cells C in which a predetermined amount of wall charges exist. The phosphor layer 28 is locally excited by ultraviolet light generated by surface discharge and emits visible light of a predetermined color. Of this visible light, the light that passes through the glass substrate 11 is the display light. Since the arrangement pattern of the partition walls 29 is a so-called stripe pattern, a portion corresponding to each column in the discharge space 30 is continuous in the column direction across all the lines. The emission colors of the sub-pixels in each column are the same. The PDP 1 having the above configuration is used as a monitor of a computer system, a wall-mounted TV, or the like in combination with a drive unit (not shown).
[0017]
Next, a driving method of the PDP 1 will be described.
FIG. 3 is a configuration diagram of the field f, and FIG. 4 is a waveform diagram of the applied voltage.
For display by the PDP 1, for example, one field f is associated with a screen (one frame). However, when reproducing a screen scanned in an interlaced format like a television, two fields f are used to display one screen (one frame).
[0018]
The field f is divided into, for example, eight subfields sf in order to perform gradation display. Further, each subfield sf is divided into a reset period TR, an address period TA, and a sustain period TS. Weighting is performed so that the relative ratio of luminance in each subfield sf is, for example, 1: 2: 4: 8: 16: 32: 64: 128, and the number of light emission in the sustain period TS of each subfield sf is set. Thus the number of gradations of the sub-pixel is capable of displaying 256 ^three colors at 256, and the pixel. Each subfield sf is a screen display period of one gradation level.
[0019]
The reset period TR is a period in which a predetermined charging state is formed by a procedure described later in order to prevent the influence of the lighting state of the previous screen and to enable line-sequential addressing. The operation of the drive unit during the reset period TR corresponds to the first operation of the present invention.
[0020]
The address period TA is a period in which line-sequential addressing is performed. The sustain electrodes X and the sustain electrodes Y are sequentially selected one by one without distinction, and a negative scan pulse Py is applied to the selected electrodes. Simultaneously with the selection of the line, a positive address pulse Pa is applied to the address electrode A corresponding to the surface discharge cell to be turned on. Of the two lines corresponding to the selected sustain electrode, in one of the two lines where the same negative wall charge as the scan pulse Py is present, the surface discharge cell to which the address pulse Pa is applied causes the connection between the sustain electrode and the address electrode. An inter-discharge occurs. This discharge forms a charged state required for the sustain operation. The operation in the address period TA corresponds to a second operation of the present invention.
[0021]
The sustain period TS is a period for maintaining a lighting state set by addressing in order to secure luminance according to a gradation level. In order to prevent a counter discharge, all the address electrodes A are biased to a positive potential (for example, Vs / 2), and a positive sustain pulse Ps having a peak value Vs is alternately applied to the sustain electrode X and the sustain electrode Y. Is applied. Each time the sustain pulse Ps is applied, surface discharge occurs in the cell in which the wall charges are accumulated in the address period TA. The operation in the sustain period TS corresponds to a third operation of the present invention.
[0022]
FIG. 5 is a schematic diagram showing a change in the charged state during the reset period TR. The symbol “☆” in the figure indicates discharge.
Hereinafter, the operation in the reset period TR will be described in detail with reference to FIGS.
[0023]
In the reset period TR, the sustain electrodes X are classified into two electrode groups, and the sustain electrodes Y are also classified into two electrode groups. That is, the sustain electrodes X and Y are classified into four electrode groups.
[0024]
The first group is a set of (1 + 4M) th sustain electrodes X (hereinafter, referred to as sustain electrodes Xa) counted from one end side (leading line side) of the electrode array without distinguishing the sustain electrodes X and Y [FIG. 1 (B)]. Here, M is a positive integer including 0. The second group is a set of (2 + 4M) th sustain electrodes Y (hereinafter, referred to as sustain electrodes Ya). The third group is a set of (3 + 4M) th sustain electrodes X (hereinafter, referred to as sustain electrodes Xb). The fourth group is a set of (4 + 4M) th sustain electrodes Y (hereinafter, referred to as sustain electrodes Yb).
[0025]
First, at timing a in FIG. 4, for example, a positive write pulse Pw is applied to the sustain electrodes Ya and Yb to cause discharge in all lines. As a result, as shown in FIG. 5A, the polarity of the wall charges is different between the sustain electrodes Xa, Xb and the sustain electrodes Ya, Yb, and the two corresponding to the individual sustain electrodes Xa, Xb, Ya, Yb. A charged state having the same polarity between the lines is formed. That is, the charged state of each sustain electrode is mirror-symmetric with respect to the partition wall 19 as a mirror surface. If the mirror symmetry remains, two lines will be selected when the scan pulse Py is applied to each electrode.
[0026]
In order to break the mirror symmetry, a negative pulse Pi is applied to the sustain electrode Ya at a timing b in FIG. 4 and a positive pulse Pi is applied to the sustain electrode Xb. Further, a positive pulse Pi is applied to the sustain electrode Xa at the timing c in FIG. 4 and a negative pulse Pi is applied to the sustain electrode Yb. The peak values of the pulses Pi and Pj are selected such that a discharge occurs only in the line to which both the pulses Pi and Pj are applied [FIGS. 5B and 5C].
[0027]
By the above three-stage processing, as shown in FIG. 5 (c), negative wall charges exist on one side in the column direction of the dielectric layer 17 in the unit light emitting region in all lines, and on the other side, A charged state in which charges of opposite polarity (here, positive polarity) exist without substantially negative wall charges is formed, and preparation for addressing is completed.
[0028]
In this state, when the sustain electrodes Xa, Xb, Ya, and Yb are sequentially selected one by one and the negative scan pulse Py is applied as described above, a counter discharge occurs in the line where the negative wall charges exist. The actual line scanning may be selected in order from the second sustain electrode in the electrode array.
[0029]
In the above-described embodiment, the driving method for forming the wall charge state as shown in FIG. 5C in the reset period TR has been described. In order to compensate for the difference in the accumulated charge amount, it is desirable to generate an erase discharge following the formation of the wall charge state shown in FIG. Specifically, a positive erase pulse Pe is applied to the sustain electrodes Xa and Xb at the timing d in FIG. 4, and a positive erase pulse Pe is applied to the sustain electrodes Ya and Yb at the timing e in FIG. In the example of FIG. 5, in order to more reliably generate an erasing discharge, the application sequence of the erasing pulse Pe is selected such that erasing is performed first at a line where no discharge occurs at timing b in consideration of the attenuation of wall charges. ing. By causing an erasing discharge to eliminate unnecessary wall charges, the wall charge accumulation state is made uniform, and the operation margin is widened.
[0030]
In the above-described embodiment, the target of the pulse application at the timings b to e is described as being fixed. However, it is preferable that the pulse is changed periodically. That is, when the target is fixed, a difference occurs in the number of discharges in the reset period TR between the odd-numbered lines and the even-numbered lines, as is apparent from FIG. Therefore, for example, by shifting the application target of the pulses Pi and Pj and the erase pulse Pe for each subfield sf with respect to the immediately preceding subfield sf, the number of discharges can be equalized.
[0031]
【The invention's effect】
According to the first to third aspects of the present invention, in a PDP having a structure in which a sustain electrode is shared for displaying two adjacent lines, a drive in which addressing operation and sustain operation are performed in a time-division manner is realized. Can be speeded up.
[Brief description of the drawings]
FIG. 1 is a schematic view of an electrode configuration of a PDP according to the present invention.
FIG. 2 is a diagram showing an internal structure of a PDP.
FIG. 3 is a configuration diagram of a field.
FIG. 4 is a waveform diagram of an applied voltage.
FIG. 5 is a schematic diagram illustrating a change in a charged state during a reset period.
[Explanation of symbols]
1 PDP
X, Y sustain electrode

Claims (3)

A method of driving a PDP configured to perform a matrix display in which the number of lines is n (n ≧ 4) by (n + 1) sustain electrodes extending in the line direction,
A first operation of forming a charged state in which wall charges of the first polarity are present on one side in the column direction in the unit light emitting region in all the lines and substantially no wall charges of the first polarity are present on the other side; A PDP driving method, comprising repeating a second operation for performing line-sequential addressing using the first polarity wall charges and a third operation for simultaneously applying a sustain voltage to all lines. . A first group (K = 2 + 4M) that satisfies the condition (K = 1 + 4M), in which a value K of the sustain electrodes counted from one end side in the arrangement direction is represented using a positive integer M including 0. When divided into a second group satisfying the condition, a third group satisfying the condition (K = 3 + 4M), and a fourth group satisfying the condition (K = 4 + 4M),
The first operation includes:
A first step of causing a discharge between all sustain electrodes;
A second step of causing a discharge between the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto;
3. The method of driving a PDP according to claim 1, comprising: a third step of causing a discharge between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto . A first group (K = 2 + 4M) that satisfies the condition (K = 1 + 4M), in which the value K of the sustain electrodes counted from one end side in the arrangement direction is expressed using a positive integer M including 0. When divided into a second group satisfying the condition, a third group satisfying the condition (K = 3 + 4M), and a fourth group satisfying the condition (K = 4 + 4M),
The first operation includes:
A first step of causing a discharge between all sustain electrodes;
A second step of causing a discharge between the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto;
A third step of causing a discharge between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto;
Discharge occurs between the first group of sustain electrodes and the second group of sustain electrodes adjacent thereto, and between the third group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto. A fourth step of
Discharge occurs between the first group of sustain electrodes and the fourth group of sustain electrodes adjacent thereto and between the second group of sustain electrodes and the third group of sustain electrodes adjacent thereto. 2. The method of driving a PDP according to claim 1, further comprising the step of:

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