JP2011099990A - Method for driving plasma display device, plasma display device, and plasma display system - Google Patents

Abstract

A high-quality stereoscopic image is displayed by suppressing crosstalk between an image for a right eye and an image for a left eye and stabilizing an address discharge.
A driving method for a plasma display apparatus, wherein a right-eye field for displaying a right-eye image signal and a left-eye field for displaying a left-eye image signal are alternately repeated, and a right-eye field and a left-eye field are displayed. In each case, the subfield with the largest luminance weight is arranged first, the subfields are arranged so that the luminance weight is sequentially reduced thereafter, the subfield with the smallest luminance weight is arranged at the end, and arranged at the end. Forcible initialization operation is performed during the initialization period of the selected subfield, selective initialization operation is performed during the initialization period of the subfield placed before that, and writing is performed in subfields other than the last subfield of the next field. In a discharge cell that discharges, even a sub-field arranged at the end of the current field is written. The discharge is carried out.
[Selection] Figure 5

Description

  The present invention relates to a plasma display device driving method, a plasma display device, and a plasma display system that alternately display a right-eye image and a left-eye image that can be stereoscopically viewed using shutter glasses on a plasma display panel.

  A typical AC surface discharge panel as a plasma display panel (hereinafter abbreviated as “panel”) includes a front substrate on which a plurality of display electrode pairs each composed of a pair of scan electrodes and sustain electrodes are formed, and a plurality of data. A rear substrate on which electrodes are formed is disposed oppositely, and a large number of discharge cells are formed therebetween. Then, ultraviolet rays are generated by gas discharge in the discharge cell, and the phosphors of red, green and blue colors are excited and emitted by the ultraviolet rays to perform color display.

  As a method for driving the panel, a subfield method in which gradation display is performed by dividing a field period into a plurality of subfields and then combining the subfields to emit light is generally used. Each subfield has an initialization period, an address period, and a sustain period. In the initialization period, an initialization discharge is generated, and an initialization operation for forming wall charges necessary for the subsequent address operation is performed. The initializing operation includes a forced initializing operation that generates an initializing discharge regardless of the operation of the immediately preceding subfield, and a selective initializing that generates an initializing discharge only in the discharge cells that have performed address discharge in the immediately preceding subfield. There is movement. In the address period, address discharge is selectively generated in the discharge cells in accordance with the image to be displayed to form wall charges. In the sustain period, a sustain pulse is alternately applied to the scan electrode and the sustain electrode to generate a sustain discharge, and the phosphor layer of the corresponding discharge cell is caused to emit light, thereby displaying an image. The light emission of the phosphor layer due to the sustain discharge is light emission related to gradation display, and the light emission accompanying the forced initialization operation is light emission not related to gradation display.

  A driving method for improving contrast by reducing luminance when displaying black, which is the lowest gradation among the subfield methods, and reducing light emission not related to gradation display as much as possible has been studied. For example, Patent Document 1 discloses a driving method in which the forced initialization operation is performed once per field and the forced initialization operation is performed using a slowly changing ramp waveform voltage.

  A method for displaying a stereoscopic image using such a panel is also being studied. As one of them, a plurality of subfields are divided into a subfield group displaying a right-eye image and a subfield group displaying a left-eye image, and the first subfield writing period of each subfield group is started. A method of opening and closing the shutter of the shutter glasses synchronously is known (see, for example, Patent Document 2).

  In order to perform stereoscopic viewing by such a method, it is necessary to see different images for the right eye and the left eye. Therefore, shutter glasses having a right-eye shutter and a left-eye shutter are used, and during the period when the right-eye image is displayed, the right-eye shutter is opened and the left-eye shutter is closed, and the left-eye image is made invisible by the left eye. In the period during which the left eye shutter is displayed, the left eye shutter is opened and the right eye shutter is closed so that the left eye image cannot be seen with the right eye.

JP 2000-242224 A JP 2000-112428 A

  However, the phosphor used in the panel has a long afterglow time, and there is a phosphor material having a characteristic that afterglow lasts for several milliseconds (ms) even after the sustain discharge is finished. Therefore, the right-eye image remains on the panel as an afterimage for a while after the period for displaying the right-eye image ends. If the left-eye image is displayed before the after-image of the right-eye image disappears, there is a problem that the right-eye image is mixed with the left-eye image, so-called crosstalk occurs, and stereoscopic viewing becomes difficult.

  In the driving method in which the number of forced initializing operations is reduced, the amount of wall charges and the amount of priming necessary to stably generate the address discharge largely depend on the subfield arrangement. Further, when insufficient priming, reduction of wall charges, etc. occur, the address discharge becomes unstable, and there is a problem that the image display quality deteriorates.

  The present invention has been made in view of these problems, and suppresses crosstalk between a right-eye image and a left-eye image, stabilizes address discharge, and displays a high-quality stereoscopic image. It is an object to provide a display device driving method, a plasma display device, and a plasma display system.

  In order to achieve the above object, the present invention provides a driving method of a plasma display device comprising a panel in which a plurality of discharge cells each having a scan electrode, a sustain electrode, and a data electrode are arranged, and a driving circuit for driving the panel. A right-eye field having a plurality of sub-fields and displaying a right-eye image signal and a left-eye field having a plurality of sub-fields and displaying a left-eye image signal are alternately repeated. For each of the fields, the subfield with the largest luminance weight is arranged first, the subfields are arranged so that the luminance weight is sequentially reduced thereafter, the subfield with the smallest luminance weight is arranged at the end, and finally In the initializing period of the subfield located in the area, the initializing discharge is generated regardless of the operation of the immediately preceding subfield. In the initializing period of the subfield arranged before that, the selective initializing operation in which the initializing discharge is generated only in the discharge cell in which the address discharge has been performed in the immediately preceding subfield is performed. In a discharge cell that performs address discharge in a subfield other than the last subfield of the field, address discharge is also performed in a subfield arranged at the end of the current field. By this method, it is possible to provide a driving method of a plasma display device capable of suppressing the crosstalk between the right-eye image and the left-eye image, stabilizing the address discharge, and displaying a high-quality stereoscopic image. .

  Further, according to the driving method of the plasma display apparatus of the present invention, in a discharge cell that performs address discharge in a subfield of either the right-eye field or the left-eye field, a forced initialization operation arranged at the end of the field is performed. Address discharge may also be performed in the subfield.

  The present invention also provides a plasma display apparatus comprising a panel in which a plurality of discharge cells each having a scan electrode, a sustain electrode, and a data electrode are arranged, and a drive circuit that drives the panel, wherein the drive circuit includes a plurality of subfields. And a right-eye field that displays a right-eye image signal and a left-eye field that has a plurality of subfields and displays a left-eye image signal, and each of the right-eye field and the left-eye field are The subfield with the largest luminance weight is arranged first, the subfields are arranged so that the luminance weight is sequentially reduced thereafter, the subfield with the smallest luminance weight is arranged at the end, and the subfield arranged at the end is arranged. Forced initialization that generates initialization discharge in the field initialization period regardless of the operation of the immediately preceding subfield In the initializing period of the subfield arranged before that, the selective initializing operation is performed in which the initializing discharge is generated only in the discharge cell in which the address discharge is performed in the immediately preceding subfield, and the last of the next field is performed. In a discharge cell that performs address discharge in a subfield other than the subfield, address discharge is also performed in a subfield arranged at the end of the current field. With this configuration, it is possible to provide a plasma display device that can suppress the crosstalk between the right-eye image and the left-eye image, stabilize the address discharge, and display a high-quality stereoscopic image.

  The driving circuit of the plasma display device of the present invention preferably includes a timing signal output unit that outputs timing signals synchronized with the right-eye field and the left-eye field.

  The plasma display system of the present invention includes a panel in which a plurality of discharge cells each having a scan electrode, a sustain electrode, and a data electrode are arranged, a right eye field that has a plurality of subfields and displays a right eye image signal, and a plurality of discharge cells. The left-eye field having the sub-field and displaying the left-eye image signal is alternately repeated, and the right-eye field and the left-eye field are first arranged with the sub-field having the largest luminance weight, and the luminance thereafter Subfields are arranged so that the weights become smaller sequentially, the subfield with the smallest luminance weight is arranged at the end, and the initialization period of the subfield arranged last is initialized regardless of the operation of the previous subfield. Performs a forced initializing operation to generate discharge, and the first subfield placed before that In the discharge period, a selective initialization operation is performed to generate an initializing discharge only in a discharge cell that has performed an address discharge in the immediately preceding subfield, and in a discharge cell that performs an address discharge in a subfield other than the last subfield of the next field. A driving circuit for driving the panel by performing address discharge even in the subfield arranged at the end of the current field, a timing signal output unit for outputting a timing signal synchronized with the field for the right eye and the field for the left eye, and a timing signal output unit And a shutter for opening and closing the shutter for the right eye and the shutter for the left eye based on the timing signal. The receiving unit receives the timing signal output from the shutter. With this configuration, it is possible to provide a plasma display system capable of suppressing the crosstalk between the right-eye image and the left-eye image, stabilizing the address discharge, and displaying a high-quality stereoscopic image.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the crosstalk of the image for right eyes, and the image for left eyes, the address discharge is stabilized, and the drive of the plasma display apparatus which can display the image for seeing a high quality stereoscopic image It becomes possible to provide a method, a plasma display device and a plasma display system.

It is a disassembled perspective view which shows the structure of the panel of the plasma display apparatus in (Embodiment 1) of this invention. It is an electrode array figure of the panel of the plasma display apparatus. It is the figure which shows the circuit block diagram and plasma display system of the plasma display apparatus. It is a drive voltage waveform figure applied to each electrode of the panel of the plasma display apparatus. It is a schematic diagram which shows the subfield structure of the plasma display apparatus. It is a figure which shows the coding of the plasma display apparatus. It is a figure which shows the coding of the plasma display apparatus. It is a figure which shows the coding of the plasma display apparatus in (Embodiment 2) of this invention.

  Hereinafter, a plasma display device according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing the structure of panel 10 of the plasma display device according to (Embodiment 1) of the present invention. A plurality of display electrode pairs 24 each including a scanning electrode 22 and a sustaining electrode 23 are formed on a glass front substrate 21. A dielectric layer 25 is formed so as to cover the display electrode pair 24, and a protective layer 26 is formed on the dielectric layer 25. A plurality of data electrodes 32 are formed on the back substrate 31, a dielectric layer 33 is formed so as to cover the data electrodes 32, and a grid-like partition wall 34 is formed thereon. A phosphor layer 35 that emits red, green, and blue light is provided on the side surface of the partition wall 34 and on the dielectric layer 33. The phosphor layer 35 can use (Y, Gd) BO ₃ : Eu as a red phosphor, Zn ₂ SiO ₄ : Mn as a green phosphor, and BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor. Of course, the phosphor is not limited to the above phosphor.

  The front substrate 21 and the rear substrate 31 are arranged to face each other so that the display electrode pair 24 and the data electrode 32 intersect each other with a minute discharge space interposed therebetween, and the outer peripheral portion thereof is sealed with a sealing material such as glass frit. Has been. In the discharge space, for example, a mixed gas of neon and xenon is sealed as a discharge gas. The discharge space is partitioned into a plurality of sections by partition walls 34, and discharge cells are formed at the intersections between the display electrode pairs 24 and the data electrodes 32. These discharge cells discharge and emit light to display an image.

  Note that the structure of the panel 10 is not limited to the above-described structure, and for example, the panel 10 may include a stripe-shaped partition wall.

  FIG. 2 is an electrode array diagram of panel 10 of the plasma display device according to (Embodiment 1) of the present invention. The panel 10 includes n scan electrodes SC1 to SCn (scan electrodes 22 in FIG. 1) and n sustain electrodes SU1 to SUn (sustain electrodes 23 in FIG. 1) that are long in the row direction. M data electrodes D1 to Dm (data electrodes 32 in FIG. 1) that are long in the column direction are arranged. A discharge cell is formed at a portion where one pair of scan electrode SCi (i = 1 to n) and sustain electrode SUi intersects one data electrode Dj (j = 1 to m), and the discharge cell is in the discharge space. M × n are formed. For example, a red phosphor is used for a discharge cell having a data electrode Dp (p = 3 × q: q is an integer equal to or less than m / 3), a green phosphor is used for a discharge cell having a data electrode Dp + 1, and data A blue phosphor is applied as a phosphor layer 35 to each discharge cell having the electrode Dp + 2.

  FIG. 3 is a circuit block diagram of plasma display device 40 and a plasma display system according to (Embodiment 1) of the present invention. The plasma display device 40 includes a panel 10 in which a plurality of discharge cells having scan electrodes 22, sustain electrodes 23, and data electrodes 32 are arranged, and a drive circuit that drives the panel 10. The drive circuit includes an image signal processing circuit 41, a data electrode drive circuit 42, a scan electrode drive circuit 43, a sustain electrode drive circuit 44, a timing generation circuit 45, and a timing signal output unit that outputs a timing signal for opening and closing the shutter to the shutter glasses 50. 46 and a power supply circuit (not shown) for supplying power necessary for each circuit block. The plasma display system includes a plasma display device 40 and shutter glasses 50 used by a viewer.

  The image signal processing circuit 41 alternately inputs a right-eye image signal and a left-eye image signal for each field. The input right-eye image signal is converted into right-eye image data indicating light emission / non-light emission for each subfield, and the left-eye image signal is converted into left-eye image data indicating light emission / non-light emission for each subfield. The data electrode drive circuit 42 converts the right-eye image data and the left-eye image data into address pulses corresponding to the data electrodes D1 to Dm, and applies them to the data electrodes D1 to Dm.

  The timing generation circuit 45 generates various timing signals for controlling the operation of each circuit block based on the horizontal synchronization signal and the vertical synchronization signal, and supplies them to the respective circuit blocks. In addition, a timing signal for opening and closing the shutter of the shutter glasses 50 is output to the timing signal output unit 46. The timing signal output unit 46 converts a timing signal synchronized with the right eye field and the left eye field into an infrared signal using a light emitting element such as an LED and supplies the infrared signal to the shutter glasses 50.

  Scan electrode drive circuit 43 applies a drive voltage waveform to each of scan electrodes 22 based on the timing signal, and sustain electrode drive circuit 44 applies a drive voltage waveform to sustain electrode 23 based on the timing signal. The shutter glasses 50 include a receiving unit (not shown) that receives a timing signal output from the timing signal output unit 46, a right-eye liquid crystal shutter 52R, and a left-eye liquid crystal shutter 52L, and the right eye based on the received timing signal. The liquid crystal shutter 52R for left and the liquid crystal shutter 52L for left eye are opened and closed.

  Next, a driving voltage waveform for driving panel 10 and its operation will be described. The plasma display device 40 performs gradation display by subfield method, that is, dividing one field into a plurality of subfields and controlling light emission / non-light emission of each discharge cell for each subfield. In the present embodiment, a right-eye field having a plurality of subfields and displaying a right-eye image signal and a left-eye field having a plurality of subfields and displaying a left-eye image signal are alternately and repeatedly displayed. The image is stereoscopically viewed using the shutter glasses 50 synchronized with the right eye field and the left eye field. In order to display a stereoscopic image without flicker, the field frequency is set to 120 Hz, which is twice the normal frequency.

  The right-eye field and the left-eye field differ only in the image signal to be displayed, and the field configuration is the same, such as the number of subfields constituting the field, the luminance weight of each subfield, and the arrangement of the subfields. First, the configuration of one field and the driving voltage waveform applied to each electrode will be described. Each field has a plurality of subfields, and each subfield includes an initialization period, an address period, and a sustain period. In the initializing period, initializing discharge is generated, and wall charges necessary for the subsequent address discharge are formed on each electrode. The initializing operation at this time includes a forced initializing operation that forcibly generates an initializing discharge regardless of whether or not there is a previous discharge, and a discharge cell that has performed an address discharge in the immediately preceding address period. There is a selective initializing operation for generating an initializing discharge. In the address period, address discharge is generated in the discharge cells to emit light to form wall charges. In the sustain period, the number of sustain pulses corresponding to the luminance weight is alternately applied to the display electrode pair 24 to generate a sustain discharge in the discharge cells that have generated the address discharge, thereby causing light emission.

  In the present embodiment, one field is divided into five subfields (SF1, SF2, SF3, SF4, SF5), and each subfield has a luminance weight of (16, 8, 4, 2, 1). In this way, the subfield with the largest luminance weight is arranged at the beginning of the field, the subfield is arranged so that the luminance weight is sequentially reduced after that, and the subfield with the smallest luminance weight is arranged at the end of the field. is doing.

  In the present embodiment, the forced initialization operation is performed in the initialization period of SF5, which is the subfield arranged at the end of the field, and the initialization periods of SF1 to SF4, which are subfields arranged before that, are performed. Perform selective initialization.

  FIG. 4 is a waveform diagram of drive voltage applied to each electrode of panel 10 of plasma display device 40 according to (Embodiment 1) of the present invention.

  In the initialization period of SF1 in which the selective initialization operation is performed, voltage Ve1 is applied to sustain electrode SU1 through sustain electrode SUn, voltage 0 (V) is applied to data electrode D1 through data electrode Dm, and scan electrode SC1 through scan electrode SCn. Is applied with a ramp waveform voltage that gradually falls toward the voltage Vi4. Then, a weak initializing discharge is generated in the discharge cell in which the sustain discharge has occurred in SF5 (not shown) one field before the immediately preceding subfield, and the wall voltage (here, the scan electrode SCi and the sustain electrode SUi). The wall voltage on the electrode represents the voltage generated by the wall charges accumulated on the dielectric layer covering the electrode, the protective layer, the phosphor layer, etc.). For data electrode Dk, a sufficient positive wall voltage is accumulated on data electrode Dk by the last sustain discharge, so that an excessive portion of this wall voltage is discharged, and the wall voltage suitable for the write operation is obtained. Adjusted to On the other hand, discharge cells that have not caused a sustain discharge in the immediately preceding subfield are not discharged, and the previous wall voltage is maintained.

  As described above, the selective initializing operation is an operation for selectively performing the initializing discharge on the discharge cell that has performed the address operation in the address period of the immediately preceding subfield, and thus the discharge cell that has performed the sustain operation in the sustain period. .

  In the subsequent address period, voltage Ve2 is applied to sustain electrode SU1 through sustain electrode SUn, and voltage Vc is applied to each of scan electrode SC1, scan electrode SC2,..., Scan electrode SCn.

  Next, a scan pulse with a negative voltage Va is applied to the first scan electrode SC1. Then, an address pulse of a positive voltage Vd is applied to the data electrode Dk (k = 1 to m) of the discharge cell to be lit in the first row among the data electrodes D1 to Dm. Then, the voltage difference at the intersection between the data electrode Dk and the scan electrode SC1 of the discharge cell to which the address pulse is applied is the difference between the externally applied voltage (Vd−Va) and the wall voltage on the data electrode Dk and the scan electrode SC1. And the difference between the wall voltages of the two is added and exceeds the discharge start voltage. Then, address discharge occurs between data electrode Dk and scan electrode SC1, and between sustain electrode SU1 and scan electrode SC1, positive wall voltage is accumulated on scan electrode SC1, and negative wall is applied on sustain electrode SU1. A voltage is accumulated, and a negative wall voltage is also accumulated on the data electrode Dk. In this manner, an address operation is performed in which an address discharge is caused in the discharge cells to be lit in the first row and wall voltage is accumulated on each electrode. On the other hand, the voltage at the intersection between the data electrode to which the address pulse is not applied and the scan electrode SC1 does not exceed the discharge start voltage, so that address discharge does not occur.

  Thereafter, the write operation is similarly performed on scan electrode SC2, scan electrode SC3,..., Scan electrode SCn.

  In the subsequent sustain period, first, a sustain pulse of voltage Vs is applied to scan electrode SC1 through scan electrode SCn, and voltage 0 (V) is applied to sustain electrode SU1 through sustain electrode SUn. Then, in the discharge cell in which the address discharge has occurred, the voltage difference between scan electrode SCi and sustain electrode SUi is the voltage Vs plus the difference between the wall voltage on scan electrode SCi and the wall voltage on sustain electrode SUi. And the discharge start voltage is exceeded. Then, a sustain discharge occurs between scan electrode SCi and sustain electrode SUi, and phosphor layer 35 emits light by the ultraviolet rays generated at this time. Then, a negative wall voltage is accumulated on scan electrode SCi, and a positive wall voltage is accumulated on sustain electrode SUi. Further, a positive wall voltage is accumulated on the data electrode Dk. In the discharge cells in which no address discharge has occurred during the address period, no sustain discharge occurs, and the wall voltage at the end of the initialization period is maintained.

  Subsequently, voltage 0 (V) is applied to scan electrode SC1 through scan electrode SCn, and sustain pulse of voltage Vs is applied to sustain electrode SU1 through sustain electrode SUn. Then, in the discharge cell in which the sustain discharge has occurred, the voltage difference between the sustain electrode SUi and the scan electrode SCi exceeds the discharge start voltage, so that the sustain discharge occurs again between the sustain electrode SUi and the scan electrode SCi. A negative wall voltage is accumulated on SUi, and a positive wall voltage is accumulated on scan electrode SCi. In this way, the number of sustain pulses corresponding to the luminance weight is alternately applied to scan electrode SC1 through scan electrode SCn and sustain electrode SU1 through sustain electrode SUn, and a sustain discharge is generated in the discharge cells that have caused the address discharge in the address period. Generate continuously.

  Then, at the end of the sustain period, a ramp waveform voltage that gradually increases toward voltage Vr is applied to scan electrode SC1 through scan electrode SCn, leaving positive wall voltage on data electrode Dk, and scan electrode SCi. The wall voltage on the upper and sustain electrodes SUi is weakened. Thus, the maintenance operation in the maintenance period is completed.

  The operation in the initialization period of SF2 for performing the selective initialization operation is the same as the operation in the initialization period of SF1. That is, voltage Ve1 is applied to sustain electrode SU1 through sustain electrode SUn, and voltage 0 (V) is applied to data electrode D1 through data electrode Dm, respectively, and the voltage gradually decreases toward scan electrode SC1 through scan electrode SCn toward voltage Vi4. Apply ramp waveform voltage. Then, a weak initializing discharge is generated in the discharge cell that has caused the sustain discharge in the immediately preceding subfield SF1, and the wall voltage on scan electrode SCi and sustain electrode SUi is weakened. For data electrode Dk, a sufficient positive wall voltage is accumulated on data electrode Dk by the last sustain discharge, so that an excessive portion of this wall voltage is discharged, and the wall voltage suitable for the write operation is obtained. Adjusted to On the other hand, discharge cells that have not caused a sustain discharge in the immediately preceding subfield are not discharged, and the previous wall voltage is maintained.

  The subsequent operation in the write period is the same as the operation in the write period of SF1, and thus description thereof is omitted. The operation in the subsequent sustain period is the same as the operation in the sustain period of SF1 except for the number of sustain pulses. The subsequent operations of SF3 to SF4 are the same as those of SF2 except for the number of sustain pulses.

  In the first half of the initialization period of SF5 in which the forced initialization operation is performed, voltage 0 (V) is applied to data electrode D1 to data electrode Dm, and voltage 0 (V) is applied to sustain electrode SU1 to sustain electrode SUn. Scan electrode SC <b> 1 to scan electrode SCn are applied with a ramp waveform voltage that gradually increases from sustain voltage SU <b> 1 to sustain electrode SUn to voltage Vi <b> 2 that is lower than the discharge start voltage toward voltage Vi <b> 2 that exceeds the discharge start voltage. . While this ramp waveform voltage rises, a weak initializing discharge occurs between scan electrode SC1 through scan electrode SCn, sustain electrode SU1 through sustain electrode SUn, and data electrode D1 through data electrode Dm. Negative wall voltage is accumulated on scan electrode SC1 through scan electrode SCn, and positive wall voltage is accumulated on data electrode D1 through data electrode Dm and sustain electrode SU1 through sustain electrode SUn.

  In the second half of the initialization period, positive voltage Ve1 is applied to sustain electrode SU1 through sustain electrode SUn, and scan electrode SC1 through scan electrode SCn have a discharge start voltage lower than sustain electrode SU1 through sustain electrode SUn. A ramp waveform voltage that gently falls from voltage Vi3 toward voltage Vi4 that exceeds the discharge start voltage is applied. During this time, weak initializing discharges occur between scan electrode SC1 through scan electrode SCn, sustain electrode SU1 through sustain electrode SUn, and data electrode D1 through data electrode Dm. Then, the negative wall voltage on scan electrode SC1 through scan electrode SCn and the positive wall voltage on sustain electrode SU1 through sustain electrode SUn are weakened, and the positive wall voltage on data electrode D1 through data electrode Dm becomes the write operation. It is adjusted to a suitable value. Thus, the forced initializing operation for forcibly performing initializing discharge on all the discharge cells is completed.

  The operation in the subsequent address period of SF5 is the same as the operation in the address period of SF1 to SF4, and the operation in the sustain period is the same as the operation in the sustain period of SF1 to SF4 except for the number of sustain pulses.

  As described above, in the present embodiment, the subfield having the largest luminance weight is arranged first, and thereafter the subfield is arranged so that the luminance weight is sequentially reduced, and finally the subfield having the smallest luminance weight is arranged. In the initializing period of the last arranged subfield, a forced initializing operation is performed to generate an initializing discharge regardless of the operation of the immediately preceding subfield, and the previous subfield is initialized. In the period, a selective initializing operation is performed in which the initializing discharge is generated only in the discharge cells in which the address discharge has been performed in the immediately preceding subfield.

  In this embodiment, voltage values applied to the electrodes are, for example, voltage Vi1 = 145 (V), voltage Vi2 = 335 (V), voltage Vi3 = 190 (V), and voltage Vi4 = −160 (V). , Voltage Va = −180 (V), voltage Vc = −35 (V), voltage Vs = 190 (V), voltage Vr = 190 (V), voltage Ve1 = 125 (V), voltage Ve2 = 130 (V) The voltage Vd is 60 (V). However, these voltage values are merely an example, and it is desirable to set them to optimum values as appropriate in accordance with the characteristics of the panel 10 and the specifications of the plasma display device 40.

  Next, the subfield configuration of plasma display apparatus 40 in the present embodiment will be described again. FIG. 5 is a schematic diagram showing a subfield configuration of plasma display device 40 according to (Embodiment 1) of the present invention. In the present embodiment, in order to display a stereoscopic image, the field frequency is set to 120 Hz, which is twice the normal frequency, and the right-eye field and the left-eye field are alternately arranged. In one field, five subfields (SF1, SF2, SF3, SF4, SF5) are arranged. Each of the subfields (SF1, SF2, SF3, SF4, SF5) has a luminance weight of (16, 8, 4, 2, 1).

  Thus, one field is composed of five subfields arranged in the order of subfields having a large luminance weight. That is, the subfield with the largest luminance weight is arranged at the beginning of the field, the subfield with the second largest luminance weight is arranged in the second of the field, and the subfield with the third largest luminance weight is arranged in the field. The subfield having the fourth largest luminance weight is arranged in the fourth field, and the subfield having the smallest luminance weight is arranged at the end of the field. Further, the forced initialization operation is performed in the initialization period of the subfield arranged at the end of the field, and the selective initialization operation is performed in the initialization periods of the other subfields.

  The right eye liquid crystal shutter 52R and the left eye liquid crystal shutter 52L of the shutter glasses 50 receive the timing signal output from the timing signal output unit 46, and control the shutter glasses 50 as follows. The right-eye liquid crystal shutter 52R of the shutter glasses 50 opens the shutter in synchronization with the start of the writing period of SF1 in the right-eye field, and closes the shutter in synchronization with the end of the maintenance period of SF5 in the right-eye field. The left-eye liquid crystal shutter 52L opens the shutter in synchronization with the start of the writing period of SF1 in the left-eye field, and closes the shutter in synchronization with the end of the maintenance period of SF5 in the left-eye field.

  By arranging the subfield and controlling the shutter glasses 50 in this way, the crosstalk between the right-eye image and the left-eye image is suppressed, the address discharge is stabilized, and a high-quality stereoscopic image is displayed. Can do. The reason will be described below.

  The intensity of afterglow of the phosphor is proportional to the luminance when the phosphor emits light, and exhibits a characteristic of decaying with a constant time constant. Since the emission luminance in the sustain period is higher in the subfield having a larger luminance weight, it is desirable to arrange the subfield having a larger luminance weight early in the field in order to weaken the afterglow. Therefore, in this embodiment, in order to suppress crosstalk, subfields are arranged in order from the subfield having the largest luminance weight.

  On the other hand, when considering the stability of the address discharge, since a sustain cell generates sustain discharges in a plurality of subfields in a discharge cell displaying a bright gradation, a sufficient amount of priming associated with these sustain discharges is supplied and stable addressing is performed. A discharge can be generated. However, in discharge cells that should emit light only in dark tones, particularly in the field with the smallest luminance weight, the priming is insufficient and the address discharge tends to become unstable.

  In the present embodiment, the forced initialization operation is performed in the initialization period of SF5, which is the subfield with the smallest luminance weight. Therefore, since the address discharge of SF5 can be generated while the priming generated by the forced initialization operation remains, stable address can be obtained even in a discharge cell that emits light only with SF5 that is the subfield having the smallest luminance weight. A discharge can be generated. In the initializing period of other subfields, selective initializing operation is performed to improve the contrast.

  Next, a gradation display method in this embodiment will be described. 6A and 6B show the relationship between the gradation to be displayed on the plasma display device 40 according to (Embodiment 1) of the present invention and the presence or absence of the subfield writing operation at that time (hereinafter abbreviated as “coding”). ), “1” indicates that the write operation is performed, and “0” indicates that the write operation is not performed. Further, “*” indicates one of them. Here, FIG. 6A shows the coding in the current field, and FIG. 6B shows the relationship between the coding in the current field and the coding in the next field.

  For example, in a discharge cell displaying gradation “0”, that is, black, the address operation is not performed in all the subfields SF1 to SF5, so that the discharge cell never has a sustain discharge and has the lowest luminance. However, although details will be described later, in the present embodiment, even in a discharge cell that displays gradation “0”, an address operation may be performed in SF5 depending on the gradation displayed in the next field. In the discharge cell displaying gradation “1”, the address operation is performed only in SF5 which is the subfield having the luminance weight “1”, and the address operation is not performed in the other subfields. Then, the discharge cell generates the number of sustain discharges corresponding to the luminance weight “1” and displays the brightness of “1”. In the discharge cell displaying the gradation “2”, the address operation is performed only with the SF 4 having the luminance weight “2”. Then, the discharge cell generates the number of sustain discharges corresponding to the luminance weight “2” in the sustain period of SF4 and displays the brightness of “2”. However, in the present embodiment, even in a discharge cell that displays gradation “2”, an address operation may be performed even in SF5 depending on the gradation displayed in the next field. In the discharge cell displaying the gradation “3”, an address operation is performed with SF4 having the luminance weight “2” and SF5 having the luminance weight “1”. Then, the discharge cell generates the number of sustain discharges corresponding to the luminance weight “2” during the sustain period of SF4 and the number of sustain discharges according to the luminance weight “1” during the sustain period of SF5. The brightness of “3” is displayed.

  Similarly, the other gradations are controlled so that the write operation is performed or not performed in each subfield according to the coding shown in FIG. 6A. However, in the present embodiment, the forced initialization operation is performed, and the writing operation is performed on the SF5 which is the subfield arranged at the end of the field with the smallest luminance weight according to the gradation displayed in the next field. There is a case. Specifically, as shown in FIG. 6B, a discharge cell that performs an address operation in any of the subfields arranged before the forced initializing operation of the next field, that is, in any of SF1 to SF4 of the next field. Then, regardless of the gradation displayed in the current field, control is performed so that the writing operation is also performed in SF5 of the current field.

  The reason why the writing of SF5 is controlled depending on not only the gradation displayed in the current field but also the gradation displayed in the next field is as follows.

  In the present embodiment, SF1, which is a subfield arranged at the beginning of the field, is a subfield having a large luminance weight and performing selective initialization. Therefore, in a discharge cell that has undergone a sustain discharge in SF5 in the immediately preceding field, a stable address discharge can be generated by priming associated with the sustain discharge. However, in a discharge cell that displays a dark gradation in the immediately preceding field and does not perform sustain discharge even in SF5, priming is insufficient, and the address discharge may become stable.

  However, according to the present embodiment, a discharge cell that performs an address operation in any one of SF1 to SF4, which is a subfield other than the last subfield of the next field, is a subfield arranged at the end of the current field. Control is also performed to perform the write operation in SF5. Then, a sustain discharge is generated at SF5, and by the priming generated at this time, a stable address discharge can be generated at SF1 to SF4 in the next field.

  Of course, according to the coding shown in FIGS. 6A and 6B, an error may occur between the gradation to be displayed and the gradation actually displayed. However, since these errors are errors of gradation “1”, the influence on the image display is relatively small.

  By devising this coding, a more stable address discharge can be generated. An example thereof will be described below as (Embodiment 2).

(Embodiment 2)
The structure of panel 10 used in (Embodiment 2) of the present invention, the circuit block diagram of plasma display device 40, the drive voltage waveform applied to each electrode of panel 10 and the subfield configuration are the same as in (Embodiment 1). Since there is, description is abbreviate | omitted. The difference between (Embodiment 2) and (Embodiment 1) is coding.

  FIG. 7 is a diagram showing coding of the plasma display device 40 according to (Embodiment 2) of the present invention. Thus, in (Embodiment 2), in any one of the right-eye field and the left-eye field, the discharge cell that performs the address discharge in any subfield of the current field is arranged at the end of the current field. Control is also performed so that address discharge is performed even in the subfield in which the forced initialization operation is performed. Further, even in a discharge cell displaying gradation “0” in the current field, a discharge cell that performs an address operation in any of subfields SF1 to SF4 that are arranged before the forced initialization operation of the next field is used. On the other hand, control is performed so that the write operation is performed even in SF5 of the current field. By displaying gradation by such coding, in the discharge cell that performs the address operation in any of SF1 to SF4 in the next field, a sustain discharge is generated even in SF5 in the current field, and thus stable in the next field. An address discharge operation can be performed. Further, according to the coding shown in FIG. 7, for example, gradations such as gradations “2”, “4”, “6”,... Cannot be displayed. However, these gradations can be displayed in a pseudo manner by performing image signal processing in advance using, for example, an error diffusion method or a dither method for the gradations that cannot be displayed. Therefore, when displaying gradations other than gradation “0”, the gradation to be displayed in the current field is not affected by the gradation to be displayed in the next field, and no error occurs.

  In order to prevent the occurrence of crosstalk when displaying the gradation “0”, for example, the following control may be performed.

  If there is a discharge cell that displays gradation “0” in the current field and an address operation is performed in any of SF1 to SF4 in the next field, all discharges are performed in SF5 in the current field. Perform a write operation on the cell. By controlling in this way, stable address discharge can be generated without generating crosstalk.

  In (Embodiment 1) and (Embodiment 2), one field has been described as having five subfields. However, the number of subfields is not limited to the above. For example, the number of gradations that can be displayed can be further increased by further increasing the number of subfields. In (Embodiment 1) and (Embodiment 2), the luminance weight of the subfield has been described as being a power of “2”, that is, (16, 8, 4, 2, 1). However, the luminance weight of the subfield is not limited to the above. For example, by giving redundancy to the combination of subfields that determine the gradation as (12, 7, 3, 2, 1), etc., it is possible to perform coding while suppressing the occurrence of a moving image pseudo contour.

  Furthermore, in (Embodiment 1) and (Embodiment 2), when there is a margin in drive time and an idle period is provided, it is desirable to provide an idle period immediately before the forced initialization operation. By providing a pause period in this manner, the cross-talk of the subfield having a large luminance weight is reduced, and the address operation of the next field can be performed while the priming associated with the forced initialization operation remains. Can be stabilized. In the present embodiment, a slight rest period is provided between SF4 and SF5. This reduces the crosstalk of SF1 to SF4 and stabilizes the write operation of SF1 in the next field by using priming associated with the forced initialization operation of SF5.

  Further, the specific numerical values used in (Embodiment 1) and (Embodiment 2) are merely examples, and are optimally suited according to panel characteristics, plasma display device specifications, and the like. It is desirable to set a correct value.

  The present invention suppresses crosstalk between the image for the right eye and the image for the left eye, stabilizes the address discharge, and can display a high-quality stereoscopic image. A driving method for a plasma display device, a plasma display device, In addition, it is useful as a plasma display system.

DESCRIPTION OF SYMBOLS 10 Panel 22 Scan electrode 23 Sustain electrode 24 Display electrode pair 32 Data electrode 35 Phosphor layer 40 Plasma display apparatus 41 Image signal processing circuit 42 Data electrode drive circuit 43 Scan electrode drive circuit 44 Sustain electrode drive circuit 45 Timing generation circuit 46 Timing signal Output unit 50 Shutter glasses 52R Liquid crystal shutter for right eye 52L Liquid crystal shutter for left eye

Claims (5)

A plasma display device driving method comprising: a plasma display panel in which a plurality of discharge cells each having a scan electrode, a sustain electrode, and a data electrode are arranged; and a driving circuit for driving the plasma display panel,
While alternately repeating a right-eye field having a plurality of subfields and displaying a right-eye image signal and a left-eye field having a plurality of subfields and displaying a left-eye image signal,
In each of the right-eye field and the left-eye field, a subfield having the largest luminance weight is arranged first, and thereafter, the subfields are arranged so that the luminance weight is sequentially reduced, and finally, the luminance weight is smallest. Place subfields,
In the initializing period of the subfield arranged last, a forced initializing operation for generating an initializing discharge is performed regardless of the operation of the previous subfield, and in the initializing period of the subfield arranged before that, the immediately preceding subfield is operated. Perform selective initializing operation to generate initializing discharge only in the discharge cells that performed address discharge in the subfield,
A method for driving a plasma display device, characterized in that, in a discharge cell that performs address discharge in a subfield other than the last subfield of the next field, address discharge is also performed in a subfield arranged at the end of the current field. In a discharge cell that performs an address discharge in a subfield of any one of the right-eye field and the left-eye field, the address discharge is also performed in a subfield that is disposed at the end of the field and performs a forced initialization operation. The method for driving a plasma display device according to claim 1. A plasma display device comprising a plasma display panel in which a plurality of discharge cells each having a scan electrode, a sustain electrode, and a data electrode are arranged, and a drive circuit for driving the plasma display panel,
The drive circuit is
While alternately repeating a right-eye field having a plurality of subfields and displaying a right-eye image signal and a left-eye field having a plurality of subfields and displaying a left-eye image signal,
In each of the right-eye field and the left-eye field, a subfield having the largest luminance weight is arranged first, and thereafter, the subfields are arranged so that the luminance weight is sequentially reduced, and finally, the luminance weight is smallest. Place subfields,
In the initializing period of the subfield arranged last, a forced initializing operation for generating an initializing discharge is performed regardless of the operation of the previous subfield, and in the initializing period of the subfield arranged before that, the immediately preceding subfield is operated. Perform selective initializing operation to generate initializing discharge only in the discharge cells that performed address discharge in the subfield,
A plasma display apparatus characterized in that, in a discharge cell that performs address discharge in a subfield other than the last subfield of the next field, address discharge is also performed in a subfield arranged at the end of the current field. The plasma display apparatus according to claim 3, wherein the driving circuit includes a timing signal output unit that outputs a timing signal synchronized with the right-eye field and the left-eye field. A plasma display panel in which a plurality of discharge cells having scan electrodes, sustain electrodes, and data electrodes are arranged;
A right-eye field that has a plurality of subfields and displays a right-eye image signal and a left-eye field that has a plurality of subfields and displays a left-eye image signal are alternately repeated, and the right-eye field and the left-eye field For each of the fields, the subfield with the largest luminance weight is arranged first, the subfields are arranged so that the luminance weight is sequentially reduced thereafter, and the subfield with the smallest luminance weight is arranged finally, and In the initializing period of the subfield arranged last, a forced initializing operation for generating an initializing discharge is performed regardless of the operation of the immediately preceding subfield, and in the initializing period of the subfield arranged before that, Selective initialization is performed to generate initialization discharge only in the discharge cells that have performed address discharge in the field. The next field of the last subfield in the subfields other than performing the address discharge discharge cells, and a drive circuit for driving the plasma display panel performs also address discharge in the subfield arranged at the end of the current field,
A timing signal output unit that outputs a timing signal synchronized with the right-eye field and the left-eye field;
A receiving unit that receives a timing signal output from the timing signal output unit; a shutter eyeglass that includes a right-eye shutter and a left-eye shutter; and that opens and closes the right-eye shutter and the left-eye shutter based on the timing signal. A plasma display system characterized by that.

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