JP4259601B2 - Plasma display device and driving method thereof - Google Patents

Description

The present invention relates to a plasma display device and a driving method thereof .

For example, an AC type PDP is a device that displays an image by covering an electrode with a dielectric layer or the like, accumulating charges on the dielectric, controlling discharge, and exciting phosphors with ultraviolet rays generated by the discharge. . A general AC type PDP divides one field (one screen) into a plurality of subfields having different gradations, and expresses the gradation of an image by superimposing them. Each subfield includes a preliminary discharge period in which charges accumulated on the dielectric and phosphor in the vicinity of the electrode in the pixel (cell) are made uniform in each pixel, a write discharge period in which a cell to emit light is selected, and light emission for performing light emission display Divided into display periods. In this method, for the discharge for light emission display in the light emission display period of each subfield, for example, as shown in FIG. 5 of Patent Document 1, a voltage is alternately applied to a pair of electrodes.

JP-A-8-129357

For example, in an AC type PDP driving method, wall charges are used to distinguish between cells to be discharged and cells not to be discharged. When a discharge is generated in the AC type PDP, charged particles having the opposite polarity to the applied voltage are accumulated by the discharge (hereinafter referred to as wall charges), and the discharge is terminated without the discharge sustaining voltage due to the wall charges having the opposite polarity.

The driving method of the AC type PDP generates a discharge exceeding the discharge start voltage (Vb) by superimposing the accumulated wall charge potential and the applied voltage (Vs). In general, the applied voltage Vs is lower than the discharge start voltage Vb, and a cell to be discharged and a cell not to be discharged are identified by wall charges.

Usually, in the drive of such a discharge type display device such as an AC type PDP, the discharge is repeated by alternately applying a voltage to a pair of electrodes to be discharged. However, the drive circuit that alternately applies a voltage to the pair of electrodes is usually another circuit, and the voltage waveforms applied to the pair of electrodes do not necessarily match. Moreover, even if a voltage is applied from one circuit to a pair of electrodes, the electrodes in the cell of the panel are not necessarily symmetrical. For this reason, (+) charge is accumulated on one electrode side for each cell, and (-) charge is accumulated on the other side, and the charge separation gradually increases in the cell, resulting in uneven brightness and malfunction. An object of the present invention, which has contributed to image quality deterioration due to the above, is to improve the drawbacks of the prior art and provide a driving technique free from image quality deterioration due to uneven brightness or malfunction.

In order to achieve the above object, in the present invention, in the first subfield, a sustain pulse having a pulse width longer than a sustain pulse applied to the second electrode group is applied to the first electrode group, In a second subfield different from the one subfield, a sustain pulse having a pulse width longer than that of the sustain pulse applied to the first electrode group is applied to the second electrode group.

Further, in the present invention, in the first subfield, a sustain pulse having a larger applied voltage than the sustain pulse applied to the second electrode group is applied to the first electrode group, which is different from the first subfield. In the second subfield, a sustain pulse having an applied voltage larger than the sustain pulse applied to the first electrode group is applied to the second electrode group.

In the present invention, in the first subfield, a sustain pulse having a rise time or fall time longer than a sustain pulse applied to the second electrode group is applied to the first electrode group, In a second subfield different from the subfield, a sustain pulse having a rise time or a fall time longer than a sustain pulse applied to the first electrode group is applied to the second electrode group.

In the present invention, in the first subfield, a first sustain pulse is applied to the first electrode group, and a second sustain having a discharge intensity different from that of the first sustain pulse is applied to the second electrode group. In the second subfield different from the first subfield, the second sustain pulse is applied to the first electrode group, and the first sustain pulse is applied to the second electrode group. Is applied.

By applying the present invention, charge separation within a cell can be reduced, and unevenness in luminance and image quality deterioration due to malfunction can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7 by taking the case of a plasma display device as an example.

  FIG. 2 is an exploded perspective view showing a part of the structure of the PDP to which the present invention is applied. Transparent X electrodes 22 and transparent Y electrodes 23 are alternately attached in parallel to the lower surface of the front glass substrate 21. Yes. Further, an X bus electrode 24 and a Y bus electrode 25 are laminated on the X electrode 22 and the Y electrode 23, respectively. Further, the X electrode 22, the Y electrode 23, the X bus electrode 24, and the Y bus electrode 25 are covered with a dielectric 26, and a protective layer 27 such as MgO is additionally provided.

  On the other hand, on the upper surface of the rear glass substrate 28, an electrode (hereinafter referred to as an address electrode) 29 that perpendicularly intersects the X electrode 22 and the Y electrode 23 is attached. The address electrode 29 is covered with a dielectric 30. On the dielectric 30, a partition wall 31 is provided in parallel with the address electrode 29. Further, a phosphor 32 is applied to the wall surface of the partition wall 31 and the upper surface of the dielectric 30.

  FIG. 3 is a cross-sectional view of the PDP viewed from the direction of arrow A in FIG. 2, and shows one cell which is the minimum unit of the pixel. Note that the same structure as that shown in FIG. In this figure, the address electrode 29 is located between two partition walls 31, and a discharge space 33 surrounded by the front glass substrate 21, the rear glass substrate 28, and the partition walls 31 is filled with a gas for causing discharge. Has been.

  FIG. 4 is a cross-sectional view of the PDP as seen from the direction of arrow B in FIG. 2, and shows one cell. Note that the same structure as that shown in FIG. The cell boundary is a position indicated by a dotted line, but is not actually separated by a partition wall or the like.

  FIG. 5 shows the electrode arrangement of the PDP and the circuit configuration of the driving device. As shown in the figure, the X electrode 22 is connected to the X drive circuit 34, the Y electrode 23 is connected to the Y drive circuit 35, the address electrode 29 is connected to the address drive circuit 36, and a voltage is applied by each drive circuit.

  FIG. 6 is a diagram showing an operation of one field required to display one image on the PDP shown in FIG. In the present embodiment, one field 40 is divided into eight subfields 41 to 48, and each subfield indicates the state of electric charges accumulated on the dielectric and phosphor in the vicinity of the electrode in the cell. It consists of reset periods 41 to 48a for making the cells uniform, address periods 41 to 48b for defining the light emitting cells, and sustain periods 41 to 48c for causing the defined cells to emit light with a predetermined brightness.

  Since the number of discharges is changed for each subfield, the length of the period during which the light emission display is performed is different, and display with different brightness is possible. The gradation of the image to be displayed is expressed by selectively emitting light during the sustain periods 41 to 48c. In FIG. 6, the subfields are arranged in ascending order of the number of sustain pulses, but the subfield arrangement order is arbitrary.

FIG. 1 shows voltage waveforms applied to the respective electrodes in one subfield for explaining the first embodiment of the present invention. FIG. 1A shows a voltage waveform applied to one X electrode, which is applied by the X drive circuit 34. FIG. 1B shows voltage waveforms applied to one Y electrode, which are applied by the Y scan circuit 35. FIG. 1C shows a voltage waveform applied to one address electrode, which is applied by the address drive circuit 36. Moreover, (d) shows light emission (for example, near-infrared light having a wavelength of 828 nm) due to discharge of the cell including the Y electrode to which the voltage waveform shown in (b) is applied.

In the reset period 41 to 48 a, the reset pulse 1 is applied to the X electrode 22. In the address periods 41 to 48b, the X scan pulse 2 is applied to the X electrode 22, the Y scan pulse 3 is applied to the Y electrode 23, and the address pulse 4 is applied to the address electrode 29. In the sustain periods 41 to 48c, the first sustain pulse 5 whose application time (width) is t1 and the second sustain pulse 6 whose application time (width) is t2 are applied to the X electrode 22 and the Y electrode 23. Here, t1 is longer than t2 by at least 0.2 μs.

Due to this voltage waveform, discharges 7 and 8 are generated at the rise and fall of the reset pulse 1 applied to the X electrode 22 in the reset periods 41 to 48a.

In the address periods 41 to 48b, the address discharge 9 is generated only in the cells in which the scan pulse 3 and the address pulse 4 are simultaneously applied to the Y electrode 23 and the address electrode 29, respectively.

In the sustain periods 41 to 48 c, discharges 10 and 11 are generated at the rising edges of the first sustain pulse 5 and the second sustain pulse 6 applied to the X electrode 22 and the Y electrode 23. At this time, in the cell having no wall charge, the first and second sustain pulses 5 and 6 do not discharge.

Next, the operation of the present invention will be described. In the first sustain pulse and the second sustain pulse, the first sustain pulse is set longer than at least 0.2 μs. For this reason, when the first sustain pulse 5 is applied to the Y electrode 23 and the second sustain pulse 6 is applied to the X electrode 22, a large amount of (−) polarity charges are collected on the Y electrode 23 side. Subsequently, when the second sustain pulse 6 is applied to the Y electrode 23 and the first sustain pulse 5 is applied to the X electrode 22, a large amount of (−) polarity charges are collected on the X electrode 22 side. As described above, by alternately applying the first sustain pulse 5 and the second sustain pulse 6 having different pulse widths to the X electrode 22 and the Y electrode 23, charges of one polarity are biased and accumulated on the one electrode side. Can be prevented. This reduces charge separation in the cell, and prevents luminance unevenness and image quality deterioration due to malfunction.

Although the case where the width of the sustain pulse is different has been described in the present embodiment, the discharge intensity and the charge accumulation amount may be changed by changing the applied voltage between the first sustain pulse and the second sustain pulse. Further, the discharge intensity may be changed by changing the rising or falling time of the voltage waveform.

  As described above, in this embodiment, the sustain pulses having different widths are alternately applied to the pair of electrodes, so that charge separation is reduced in the cell, and unevenness in luminance and image quality deterioration due to malfunction can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 7 shows voltage waveforms applied to each electrode in two subfields according to the present invention. FIG. 7A shows a voltage waveform applied to one X electrode, which is applied by the X drive circuit 34. FIG. 7B shows voltage waveforms applied to one Y electrode, and is applied by the Y scan circuit 35. FIG. 7C shows a voltage waveform applied to one address electrode, which is applied by the address drive circuit 36. Moreover, (d) shows light emission (for example, near-infrared light having a wavelength of 828 nm) due to discharge of the cell including the Y electrode to which the voltage waveform shown in (b) is applied. The same waveforms as those in the first embodiment shown in FIG.

In the present embodiment, in one subfield, the first sustain pulse 5 is applied to the Y electrode 23, and the second sustain pulse 6 is applied to the X electrode 22. Subsequently, in the next subfield, the second sustain pulse 6 is applied to the Y electrode 23 and the first sustain pulse 5 is applied to the X electrode 22. As a result, in the subfield in which the first sustain pulse 5 is applied to the Y electrode 23 and the second sustain pulse 6 is applied to the X electrode 22, a large amount of (−) polarity charge is collected on the Y electrode 23 side. . In the subsequent subfield, when the second sustain pulse 6 is applied to the Y electrode 23 and the first sustain pulse 5 is applied to the X electrode 22, a large amount of (−) polarity charge is collected on the X electrode 22 side. As described above, by alternately applying the first sustain pulse 5 and the second sustain pulse 6 having different pulse widths to the X electrode 22 and the Y electrode 23 for each subfield, the charge of one polarity is applied to the one electrode side. Uneven accumulation can be prevented. This reduces charge separation in the cell, and prevents luminance unevenness and image quality deterioration due to malfunction.

Although the case where the width of the sustain pulse is different has been described in the present embodiment, the discharge intensity and the charge accumulation amount may be changed by changing the applied voltage between the first sustain pulse and the second sustain pulse. Further, the discharge intensity may be changed by changing the rising or falling time of the voltage waveform. Further, instead of alternately applying each subfield, switching may be performed for each field.

As described above, in the present embodiment, the sustain pulses having different widths are alternately applied to the pair of electrodes within the sustain period, for each subfield, or for each field, thereby reducing charge separation in the cell. It is possible to prevent uneven brightness and image quality deterioration due to malfunction.

  In addition, although the said Example is a case of a plasma display apparatus, this invention is not limited to this.

It is an example of a drive waveform in one subfield in the configuration of the present invention. It is a disassembled perspective view which shows a part of structure in the case of PDP as one Example of this invention. It is sectional drawing of PDP seen from the direction of the arrow A in FIG. It is sectional drawing of PDP seen from the direction of arrow B in FIG. It is the figure which showed the circuit structure of PDP as one Example of this invention. It is the figure which showed the operation | movement of 1 field period which comprises one image. It is a drive waveform diagram in 2 subfields of the second embodiment of the present invention.

Explanation of symbols

1 ... Reset pulse,
3. Scan pulse,
4 ... Address pulse,
5 ... First sustain pulse,
6 ... Second sustain pulse,
21 ... Front glass substrate,
22, 52 ... X electrode,
23, 53 ... Y electrode,
24, 54 ... X bus electrode,
25, 55 ... Y bus electrode,
26: Dielectric,
27 ... Protective layer,
28 ... rear glass substrate,
29: Address electrode,
30 ... dielectric,
31 ... partition wall,
32 ... phosphor,
33 ... discharge space,
34 ... X drive circuit,
35 ... Y drive circuit,
36: Address drive circuit,
40 ... 1 field,
41-48 ... subfield,
41-48a ... reset period,
41-48b ... address period,
41 to 48c: Sustain period.

Claims (14)

An image of one field is displayed by a plurality of subfields, in which the first electrodes are arranged on a second substrate different from the first substrate, intersecting the address electrodes arranged on the first substrate. a group and driving method of a plasma display apparatus sustain pulse is alternately applied to the second electrode group,
In the first subfield, a sustain pulse having a longer pulse width than the sustain pulse applied to the second electrode group is applied to the first electrode group, and a second subfield different from the first subfield Then, a sustain pulse having a pulse width longer than that of the sustain pulse applied to the first electrode group is applied to the second electrode group. An image of one field is displayed by a plurality of subfields, in which the first electrodes are arranged on a second substrate different from the first substrate, intersecting the address electrodes arranged on the first substrate. a group and driving method of a plasma display apparatus sustain pulse is alternately applied to the second electrode group,
In the first subfield, a sustain pulse having a larger applied voltage than the sustain pulse applied to the second electrode group is applied to the first electrode group, and the second subfield is different from the first subfield. Then, a sustain pulse having a larger applied voltage than a sustain pulse applied to the first electrode group is applied to the second electrode group. An image of one field is displayed by a plurality of subfields, in which the first electrodes are arranged on a second substrate different from the first substrate, intersecting the address electrodes arranged on the first substrate. a group and driving method of a plasma display apparatus sustain pulse is alternately applied to the second electrode group,
In the first subfield, a sustain pulse having a rise time or fall time longer than the sustain pulse applied to the second electrode group is applied to the first electrode group, and the first subfield is different from the first subfield. In the second subfield, a sustain pulse having a rise time or a fall time longer than a sustain pulse applied to the first electrode group is applied to the second electrode group. Method An image of one field is displayed by a plurality of subfields, in which the first electrodes are arranged on a second substrate different from the first substrate, intersecting the address electrodes arranged on the first substrate. a group and driving method of a plasma display apparatus sustain pulse is alternately applied to the second electrode group,
In the first subfield, a first sustain pulse is applied to the first electrode group, and a second sustain pulse having a discharge intensity different from that of the first sustain pulse is applied to the second electrode group, In a second subfield different from the first subfield, the second sustain pulse is applied to the first electrode group, and the first sustain pulse is applied to the second electrode group. A method for driving a plasma display device.   5. The plasma display apparatus driving method according to claim 4, wherein the sustain pulses having different discharge intensities are sustain pulses having different application time, applied voltage, rise time or fall time. Device driving method.   6. The method of driving a plasma display device according to claim 1, wherein the first subfield and the second subfield are alternately repeated. .   7. The plasma display device driving method according to claim 1, wherein the second subfield is a subfield next to the first subfield. Driving method. A plasma display apparatus in which an image of one field is displayed by a plurality of subfields,
An address electrode disposed on a first substrate, and a first electrode group and a second electrode which intersect with the address electrode and are disposed on a second substrate different from the first substrate and can be driven independently of each other Group,
Discharging is performed by applying a sustain pulse to the first electrode group and the second electrode group, and in the first subfield, a sustain pulse applied to the first electrode group to the second electrode group A sustain pulse having a longer application time is applied, and in a second subfield different from the first subfield, the application time is longer than the sustain pulse applied to the second electrode group to the first electrode group. A plasma display device having a drive circuit for applying a sustain pulse. A plasma display apparatus in which an image of one field is displayed by a plurality of subfields,
An address electrode disposed on a first substrate, and a first electrode group and a second electrode which intersect with the address electrode and are disposed on a second substrate different from the first substrate and can be driven independently of each other Group,
Discharging is performed by applying a sustain pulse to the first electrode group and the second electrode group, and in the first subfield, a sustain pulse applied to the first electrode group to the second electrode group A sustain pulse having a larger applied voltage than the first pulse is applied, and in a second subfield different from the first subfield, the applied voltage is larger than the sustain pulse applied to the second electrode group to the first electrode group. A plasma display device having a drive circuit for applying a sustain pulse. A plasma display apparatus in which an image of one field is displayed by a plurality of subfields,
An address electrode disposed on a first substrate, and a first electrode group and a second electrode which intersect with the address electrode and are disposed on a second substrate different from the first substrate and can be driven independently of each other Group,
Discharging is performed by applying a sustain pulse to the first electrode group and the second electrode group, and in the first subfield, a sustain pulse applied to the first electrode group to the second electrode group A sustain pulse having a longer rise time or fall time is applied, and in a second subfield different from the first subfield, a sustain pulse applied to the second electrode group is applied to the first electrode group. A plasma display device having a drive circuit for applying a sustain pulse having a long rise time or a long fall time. A plasma display apparatus in which an image of one field is displayed by a plurality of subfields,
An address electrode disposed on a first substrate, and a first electrode group and a second electrode which intersect with the address electrode and are disposed on a second substrate different from the first substrate and can be driven independently of each other Group,
Discharging is performed by applying a sustain pulse to the first electrode group and the second electrode group, and a first sustain pulse is applied to the first electrode group in the first subfield, A second sustain pulse having a discharge intensity different from that of the first sustain pulse is applied to the second electrode group, and the second electrode is applied to the first electrode group in a second subfield different from the first subfield. A plasma display device having a drive circuit that applies two sustain pulses and applies the first sustain pulse to the second electrode group.   12. The plasma display apparatus according to claim 11, wherein the sustain pulses having different discharge intensities are sustain pulses having different pulse width, applied voltage, rise time or fall time.   The plasma display device according to any one of claims 8 to 12, wherein the first subfield and the second subfield are alternately repeated.   14. The plasma display device according to claim 8, wherein the second subfield is a subfield next to the first subfield.

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