JP4811053B2 - Plasma display panel driving method and plasma display device - Google Patents

Description

  The present invention relates to a driving method of a plasma display panel and a plasma display device used for a wall-mounted television or a large monitor.

  A typical AC surface discharge type panel as a plasma display panel (hereinafter abbreviated as “panel”) has a large number of discharge cells formed between a front plate and a back plate arranged to face each other.

  In the front plate, a plurality of display electrode pairs each consisting of a pair of scan electrodes and sustain electrodes are formed in parallel with each other on the front glass substrate, and a dielectric layer and a protective layer are formed so as to cover the display electrode pairs. Yes. The back plate has a plurality of parallel data electrodes on the back glass substrate, a dielectric layer so as to cover them, and a plurality of barrier ribs in parallel with the data electrodes formed on the back glass substrate. A phosphor layer is formed on the side walls of the barrier ribs.

  Then, the front plate and the back plate are arranged opposite to each other so that the display electrode pair and the data electrode are three-dimensionally crossed and sealed, and a discharge gas containing, for example, 5% xenon is enclosed in the internal discharge space. Has been. Here, a discharge cell is formed in a portion where the display electrode pair and the data electrode face each other. In the panel having such a configuration, ultraviolet rays are generated by gas discharge in each discharge cell, and the phosphors of red (R), green (G) and blue (B) colors are excited and emitted by the ultraviolet rays, thereby performing color display. It is carried out.

  As a method of driving the panel, a subfield method, that is, a method of performing gradation display by combining subfields to emit light after dividing one field period into a plurality of subfields.

  Each subfield has an initialization period, an address period, and a sustain period. In the initialization period, an initialization discharge is generated, and wall charges necessary for the subsequent address operation are formed on each electrode. The initialization operation includes an initialization operation for generating an initialization discharge in all discharge cells (hereinafter abbreviated as “all-cell initialization operation”) and an initialization discharge in a discharge cell that has undergone a sustain discharge. There is an initialization operation (hereinafter abbreviated as “selective initialization operation”).

  In the address period, address discharge is selectively generated in the discharge cells to be displayed to form wall charges. In the sustain period, a sustain pulse is alternately applied to the display electrode pair composed of the scan electrode and the sustain electrode, and a sustain discharge is generated in the discharge cell in which the address discharge is generated, and the phosphor layer of the corresponding discharge cell is caused to emit light. The image is displayed.

  In addition, among the subfield methods, initializing discharge is performed using a slowly changing voltage waveform, and further, initializing discharge is selectively performed on discharge cells that have undergone sustain discharge. A novel driving method is disclosed in which the light emission that is not generated is reduced as much as possible to improve the contrast ratio.

  Specifically, for example, among all the subfields, an all-cell initializing operation is performed in which all discharge cells are discharged in the initializing period of one subfield, and a sustain discharge is performed in the initializing period of the other subfield. A selective initialization operation for initializing only the performed discharge cells is performed. As a result, light emission unrelated to display is only light emission due to discharge in the all-cell initialization operation, and high-contrast image display is possible (for example, see Patent Document 1).

  By driving in this way, the luminance of the black display area that changes depending on the light emission not related to the image display (hereinafter abbreviated as “black luminance”) is only weak light emission in the all-cell initialization operation, High-contrast image display is possible.

  On the other hand, the number of discharge cells will increase with the higher definition and larger screen of the panel, and the number of subfields will be increased in order to improve the image display quality, such as the improvement of the video pseudo contour. There is a demand for faster write operations.

  By the way, the all-cell initializing operation for initializing all the discharge cells forms the wall charge necessary for the address operation as described above, reduces the discharge delay, and stably generates the address discharge. It also has the function of generating. Therefore, a method of increasing priming is effective for high-speed write operation. However, simply increasing the number of subfields that perform the all-cell initialization operation within one field period (hereinafter referred to as “all-cell initialization count”) increases the black luminance and decreases the contrast, thereby reducing the image display quality. Decreases.

Therefore, based on the average image level (APL: Average Picture Level) of the image signal to be displayed, the initialization operation in the initialization period of each subfield is determined as either the all-cell initialization operation or the selective initialization operation. Thus, there has been proposed a panel driving method that can increase and decrease the number of all-cell initializations and can stably perform high-speed writing while suppressing an increase in black luminance (for example, see Patent Document 2).
JP 2000-242224 A JP-A-2005-215132

  However, the wall charges and priming formed by the all-cell initialization operation are greatly affected by the discharge characteristics such as the discharge start voltage, and the discharge characteristics change depending on the panel temperature. However, there is a problem that a temperature range in which panel driving capable of stable high-speed writing can be performed while suppressing an increase in black luminance is limited to some extent.

  The present invention has been made to solve these problems, and it is an object of the present invention to provide a panel driving method and a plasma display apparatus capable of stable high-speed writing while suppressing an increase in black luminance over a wide temperature range. And

The present invention provides a sustain discharge in an all-cell initializing subfield that generates an initializing discharge for all discharge cells that perform image display in an initializing period and a subfield immediately before the initializing period within one field period. And a selective initializing subfield for selectively generating initializing discharges in the discharge cells having generated an initializing voltage for generating initializing discharges in all cell initializing subfields. The panel is driven by switching at least three types of drive modes that are variable and at least one of the number of all-cell initialization subfields and the initialization voltage is different, and the plasma display panel is configured based on the temperature around the plasma display panel. Minimum estimated temperature and all-cell emission pattern when all possible cell non-emission patterns are displayed When the temperature is displayed, the maximum estimated temperature is estimated and the low temperature drive mode is selected when the minimum estimated temperature is lower than the predetermined low temperature threshold, and when the maximum estimated temperature is equal to or higher than the predetermined high temperature threshold. At least a high temperature drive mode to be selected and a normal temperature drive mode to be selected when the minimum estimated temperature is equal to or higher than the low temperature threshold and the maximum estimated temperature is below the high temperature threshold, and all cells are initialized in the high temperature drive mode The number of subfields is set to be larger than the number of all-cell initialization subfields in the normal temperature driving mode, and the initializing voltage in the low temperature driving mode is set to a voltage value higher than the initializing voltage in the normal temperature driving mode. To do. By this method, it is possible to provide a panel driving method capable of stable high-speed writing while suppressing an increase in black luminance over a wide temperature range.

  The panel driving method of the present invention further includes an APL detection unit that detects an average luminance in one field period or one frame period of an image signal, and the number of all-cell initialization subfields based on the average luminance detected by the APL detection unit. You may comprise so that may be changed.

The plasma display apparatus of the present invention also includes a panel having a plurality of discharge cells each having a display electrode pair including a scan electrode and a sustain electrode, and a minimum estimate that the panel can take based on the temperature detected by the temperature sensor. A temperature estimation circuit for estimating the temperature and the maximum estimated temperature, and a drive circuit for driving the panel, and an initializing period for generating an initializing discharge in one discharge cell and an address for generating an address discharge in the discharge cell. A plurality of subfields each having a period and a sustain period in which a sustain discharge is generated in a discharge cell in which an address discharge has been generated. For all discharge cells that perform image display in an initialization period within one field period Sustain discharge is generated in all cell initialization subfield that generates initialization discharge and in the subfield immediately before the initialization period. A selective initializing subfield for selectively generating initializing discharges in the discharge cells, and the driving circuit can increase or decrease the number of all-cell initializing subfields and also perform initializing discharges in the all-cell initializing subfields. It can be used to adjust the initialization voltage for generating, configured as at least one of the number and the initialization voltage of all-cell initializing subfield to drive the panel by switching the different at least three types of drive modes, the peripheral plasma display panel Based on the temperature of the plasma display panel, the minimum estimated temperature when the non-light emission pattern that can be taken by the plasma display panel is displayed and the maximum estimated temperature when the light emission pattern of all cells are displayed are estimated. Low temperature drive mode to select when below threshold and high estimated temperature At least a high temperature drive mode that is selected when the temperature is above the threshold and a normal temperature drive mode that is selected when the minimum estimated temperature is equal to or higher than the low temperature threshold and the maximum estimated temperature is less than the high temperature threshold. The number of all-cell initialization subfields in the drive mode is set to be larger than the number of all-cell initialization subfields in the room temperature drive mode, and the initialization voltage in the low temperature drive mode is higher than the initialization voltage in the room temperature drive mode. It is characterized by being set to. By this method, it is possible to provide a panel driving method capable of stable high-speed writing while suppressing an increase in black luminance over a wide temperature range.

  According to the present invention, it is possible to provide a panel driving method and a plasma display device capable of stable high-speed writing while suppressing an increase in black luminance over a wide temperature range.

  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 in (Embodiment 1) of the present invention. On the glass front plate 21, a plurality of display electrode pairs 28 made up of the scan electrodes 22 and the sustain electrodes 23 are formed. A dielectric layer 24 is formed so as to cover the scan electrode 22 and the sustain electrode 23, and a protective layer 25 is formed on the dielectric layer 24. A plurality of data electrodes 32 are formed on the back plate 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 light of each color of red (R), green (G), and blue (B) is provided on the side surface of the partition wall 34 and on the dielectric layer 33.

  The front plate 21 and the back plate 31 are arranged to face each other so that the display electrode pair 28 and the data electrode 32 intersect each other with a minute discharge space interposed therebetween, and the outer periphery 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 enclosed as a discharge gas. In the present embodiment, a discharge gas with a xenon partial pressure of 10% is used to improve luminance. 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 28 and the data electrodes 32. These discharge cells discharge and emit light to display an image.

  Note that the structure of the panel is not limited to the above-described structure, and for example, a structure having a stripe-shaped partition may be used.

  FIG. 2 is an electrode array diagram of panel 10 according to (Embodiment 1) of the present invention. In panel 10, n scanning electrodes SC1 to SCn (scanning electrode 22 in FIG. 1) and n sustaining electrodes SU1 to SUn (sustaining electrode 23 in FIG. 1) long in the row direction are arranged and long in the column direction. M data electrodes D1 to Dm (data electrode 32 in FIG. 1) 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 (i = 1 to n) intersects with one data electrode Dj (j = 1 to m). , M × n discharge cells are formed in the discharge space.

  FIG. 3 is a circuit block diagram of a drive circuit for driving a panel according to (Embodiment 1) of the present invention. The plasma display device 1 includes a panel 10, an image signal processing circuit 51, a data electrode drive circuit 52, a scan electrode drive circuit 53, a sustain electrode drive circuit 54, a timing generation circuit 55, an APL detection circuit 57, a temperature estimation circuit 58, and each circuit. A power supply circuit (not shown) for supplying power necessary for the block is provided.

  The image signal processing circuit 51 converts the input image signal sig into image data indicating light emission / non-light emission for each subfield. The data electrode driving circuit 52 converts the image data for each subfield into signals corresponding to the data electrodes D1 to Dm, and drives the data electrodes D1 to Dm.

  The APL detection circuit 57 detects the average luminance level (hereinafter abbreviated as “APL”) of the image signal sig. Specifically, the APL is detected by using a generally known method such as accumulating the luminance value of the image signal over one field period or one frame period.

  The temperature estimation circuit 58 has a temperature sensor 81 made of a generally known element such as a thermocouple used for detecting the temperature. The temperature around the panel 10 detected by the temperature sensor 81, which is a housing in this embodiment. Estimated values of the maximum and minimum temperatures that the panel 10 can take (hereinafter simply referred to as “maximum estimated temperature” and “minimum estimated temperature”) are calculated from the temperature inside the body, and the results are output to the timing generation circuit 55. To do.

  The timing generation circuit 55 performs the operation of each circuit block based on the horizontal synchronization signal H, the vertical synchronization signal V, the APL detected by the APL detection circuit 57, and the highest estimated temperature and the lowest estimated temperature estimated by the temperature estimation circuit 58. Various timing signals to be controlled are generated and supplied to each circuit block. Scan electrode drive circuit 53 has an initialization waveform generation circuit 300 for generating an initialization voltage waveform to be applied to scan electrodes SC1 to SCn in the initialization period, and scan electrode SC1 to SCn is supplied based on a timing signal. Drive each one. Sustain electrode drive circuit 54 drives sustain electrodes SU1 to SUn based on the timing signal.

  FIGS. 4A and 4B are diagrams showing the mounting position of the temperature sensor of the plasma display device according to (Embodiment 1) of the present invention, FIG. 4A is a rear view of the plasma display device, and FIG. 4B is a plasma display. It is the figure which expanded sectional drawing of the apparatus. A heat conductive sheet 86 is provided in close contact with the back surface of the panel 10, and an aluminum chassis 87 is provided in close contact with the heat conductive sheet 86. A circuit board 89 provided with each drive circuit is attached to the aluminum chassis 87 via a boss member 88, and a temperature sensor 81 is attached to the surface of the circuit board 89. Accordingly, the panel 10 and the temperature sensor 81 are separated from each other with an air layer interposed therebetween, and the temperature sensor 81 is disposed at a position where it does not directly contact the panel 10 and is not directly thermally coupled to the panel 10. ing.

  Thus, in the present embodiment, the temperature sensor 81 is provided at a position where it does not directly contact any of the panel 10, the heat conductive sheet 86, and the aluminum chassis 87. Then, by sandwiching an air layer formed by the boss material 88 between the panel 10 and the temperature sensor 81, the temperature sensor 81 is prevented from coming into direct contact with the panel 10. The heat is not detected. The temperature sensor 81 may be attached to another position as long as the temperature sensor 81 is not directly thermally coupled to the panel 10.

  Next, a driving voltage waveform for driving panel 10 and its operation will be described. The plasma display device 1 performs gradation display by subfield method, that is, dividing one field period into a plurality of subfields and controlling light emission / non-light emission of each discharge cell for each subfield. Each subfield has 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 an all-cell initializing operation in which initializing discharge is generated in all discharge cells, and a selective initializing operation in which initializing discharge is generated in the discharge cells that have undergone sustain discharge.

  In the address period, address discharge is selectively generated in the discharge cells to emit light to form wall charges. In the sustain period, a number of sustain pulses proportional to the luminance weight are alternately applied to the display electrode pairs, and a sustain discharge is generated in the discharge cells that have generated the address discharge to emit light. The proportional constant at this time is called luminance magnification. The details of the subfield configuration will be described later, and here, the driving voltage waveform and its operation in the subfield will be described.

  FIG. 5 is a drive voltage waveform diagram applied to each electrode of panel 10 in (Embodiment 1) of the present invention. FIG. 5 shows a subfield for performing all-cell initialization operation and a subfield for performing selective initialization operation.

  First, subfields for performing the all-cell initialization operation will be described.

  In the first half of the initialization period, 0 (V) is applied to the data electrodes D1 to Dm and the sustain electrodes SU1 to SUn, respectively, and the scan electrodes SC1 to SCn have a voltage lower than the discharge start voltage with respect to the sustain electrodes SU1 to SUn. A ramp waveform voltage that gradually increases from Vi1 toward a voltage exceeding the discharge start voltage is applied (hereinafter, the maximum value of the slowly increasing voltage applied to scan electrodes SC1 to SCn in the first half of the initialization period). (Quoted as “initialization voltage Vr”).

  While this ramp waveform voltage rises, a weak initializing discharge occurs between scan electrodes SC1 to SCn, sustain electrodes SU1 to SUn, and data electrodes D1 to Dm. Negative wall voltage is accumulated on scan electrodes SC1 to SCn, and positive wall voltage is accumulated on data electrodes D1 to Dm and sustain electrodes SU1 to SUn. Here, the wall voltage above the electrode represents a voltage generated by wall charges accumulated on the dielectric layer covering the electrode, the protective layer, the phosphor layer, and the like.

  In the initialization discharge at this time, the wall voltage is excessively stored in anticipation of optimizing the wall voltage in the second half of the subsequent initialization period. The excessive wall voltage stored in this way can be controlled by the initialization voltage Vr. As will be described in detail later, the value of the initialization voltage Vr is not always a constant voltage, but is changed as necessary.

  In the latter half of the initialization period, positive voltage Ve1 is applied to sustain electrodes SU1 to SUn, and scan electrodes SC1 to SCn receive a discharge start voltage from voltage Vi3 that is equal to or lower than the discharge start voltage with respect to sustain electrodes SU1 to SUn. A ramp waveform voltage (hereinafter also referred to as a “ramp voltage”) that gently falls toward the exceeding voltage Vi4 is applied. During this time, weak initializing discharges occur between scan electrodes SC1 to SCn, sustain electrodes SU1 to SUn, and data electrodes D1 to Dm, respectively. Then, the negative wall voltage above scan electrodes SC1 to SCn and the positive wall voltage above sustain electrodes SU1 to SUn are weakened, and the positive wall voltage above data electrodes D1 to Dm is adjusted to a value suitable for the write operation. The Thus, the all-cell initializing operation for performing the initializing discharge on all the discharge cells is completed.

  Since the discharge at this time depends on the excessive wall voltage stored in the first half of the initialization period, if the initialization voltage Vr is low and the initialization discharge in the first half of the initialization period is weak, the second half of the initialization period The initializing discharge is also weakened. Conversely, when the initialization voltage Vr is high, both initialization discharges become strong.

  In the subsequent address period, voltage Ve2 is applied to sustain electrodes SU1 to SUn, and voltage Vc is applied to scan electrodes SC1 to SCn.

  Next, the negative scan pulse voltage Va is applied to the scan electrode SC1 in the first row, and the data electrode Dk (k = 1 to m) of the discharge cell that should emit light in the first row among the data electrodes D1 to Dm. A positive address pulse voltage Vd is applied. At this time, the voltage difference at the intersection between the data electrode Dk and the scan electrode SC1 is the difference between the wall voltage on the data electrode Dk and the wall voltage on the scan electrode SC1 due to the difference between the externally applied voltages (Vd−Va). It becomes the sum 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 of the data electrodes D1 to Dm to which the address pulse voltage Vd is not applied and the scan electrode SC1 does not exceed the discharge start voltage, so that address discharge does not occur. The above address operation is performed until the discharge cell in the nth row of scan electrode SCn, and the address period ends.

  In the subsequent sustain period, first, positive sustain pulse voltage Vs is applied to scan electrodes SC1 to SCn, and 0 (V) is applied to sustain electrodes SU1 to 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 difference between the wall voltage on scan electrode SCi and the wall voltage on sustain electrode SUi. Exceeds the discharge start voltage.

  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, 0 (V) is applied to scan electrodes SC1 to SCn, and sustain pulse voltage Vs is applied to sustain electrodes SU1 to 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. Thereafter, similarly, the sustain period is applied to the scan electrodes SC1 to SCn and the sustain electrodes SU1 to SUn by alternately multiplying the luminance weight by the luminance magnification, and a potential difference is applied between the electrodes of the display electrode pair, thereby writing the address period. The sustain discharge is continuously performed in the discharge cell in which the address discharge has occurred in FIG.

  Then, at the end of the sustain period, a so-called narrow pulse voltage difference is applied between scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn, and the positive wall voltage on data electrode Dk is left while scanning. The wall voltage on the electrode SCi and the sustain electrode SUi is erased.

  Next, the operation of the subfield that performs the selective initialization operation will be described.

  In the initialization period in which the selective initialization operation is performed, voltage Ve1 is applied to sustain electrodes SU1 to SUn, 0 (V) is applied to data electrodes D1 to Dm, and scan electrodes SC1 to SCn are moved from voltage Vi3 ′ to voltage Vi4. Apply a ramp voltage that falls slowly.

  Then, a weak initializing discharge is generated in the discharge cell that has caused the sustain discharge in the sustain period of the previous subfield, 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, the discharge cells that did not cause the sustain discharge in the previous subfield are not discharged, and the wall charges at the end of the initialization period of the previous subfield are maintained as they are. As described above, the selective initializing operation is an operation for selectively performing initializing discharge on the discharge cells that have undergone the sustain operation in the sustain period of the immediately preceding subfield.

  The operation in the subsequent address period is the same as the operation in the address period of the subfield in which the all-cell initializing operation is performed, and thus description thereof is omitted. The operation in the subsequent sustain period is the same except for the number of sustain pulses.

  Next, the subfield configuration of the panel driving method in this embodiment will be described. In the present embodiment, one field is divided into ten subfields (first SF, second SF,..., Tenth SF), and each subfield is (1, 2, 3, 6, 11, 18, It is assumed that the luminance weights are 30, 44, 60, and 80), but the number of subfields and the luminance weight of each subfield are not limited to the above values.

  In the present embodiment, the subfield configuration other than the number of subfields and the luminance weight described above is switched based on the APL of the image signal, and the subfield configuration is further configured based on the temperature inside the casing detected by the temperature sensor. Switching. Hereinafter, the subfield configuration based on temperature is abbreviated as “drive mode”.

  First, the relationship between APL and subfield configuration will be described. FIG. 6 is a diagram showing a subfield configuration according to (Embodiment 1) of the present invention. Each subfield is a subfield (hereinafter referred to as “all cell initialization”) that performs an all cell initialization operation in an initialization period. Or “subfield” (hereinafter abbreviated as “selective initialization subfield”). 6 and 7 show an outline of one field of the driving waveform of the panel, and the details of the waveform in each period of each subfield are as shown in FIG.

  In the present embodiment, the subfield configuration is switched based on the APL of the image signal to be displayed. FIG. 6A shows a configuration used when an APL is less than 6% for an image signal. Only the first SF is an all-cell initializing subfield, and the second SF to the tenth SF are selective initializing subfields. FIG. 6B shows a configuration used when an image signal having an APL of 6% or more is used. The first SF and the fourth SF are all-cell initialization subfields, and the second SF, the third SF, and the fifth SF to the tenth SF are selective initialization. It is a subfield. In other words, when the APL is less than the threshold value of 6%, the number of times of all cell initialization is one, and when the threshold value is 6% or more, the number of times of all cell initialization is two. The following (Table 1) shows the relationship between the above-described subfield configuration and APL.

  The above is a normally used drive mode (hereinafter referred to as “room temperature drive mode”). In this embodiment, a low temperature drive mode and a high temperature drive mode are provided in addition to the room temperature drive mode.

  FIG. 7 is a diagram showing a subfield configuration in (Embodiment 1) of the present invention. As an example, the subfield configuration is shown for three drive modes used for an image signal with an APL of less than 6%.

  FIG. 7A shows an example of the low temperature driving mode. The low temperature driving mode is a driving mode in which stable image display can be performed even when the temperature of the panel 10 is low. For example, immediately after the plasma display device is installed in a low temperature environment and the power is turned on. This is a driving mode used before the panel temperature rises.

  In the low temperature drive mode in the present embodiment, the all-cell initialization operation is performed in the first SF and the fourth SF, and the selective initialization operation is performed in the other subfields. The initialization voltage Vr at this time is set to a voltage value VrH that is higher than the initialization voltage value VrC in each of the normal temperature driving mode and the high temperature driving mode described later.

  FIG. 7B shows the room temperature driving mode described above. The room temperature drive mode is a drive mode that is normally used. In the present embodiment, the all-cell initialization operation is performed in the first SF and the fourth SF, and the selective initialization operation is performed in the other subfields. The initialization voltage Vr at this time is set to a voltage value VrC lower than the initialization voltage value VrH in the low temperature drive mode.

  Next, FIG. 7C shows an example of the high temperature driving mode. The high temperature driving mode is a driving mode in which stable image display can be performed even when the temperature of the panel 10 is high. For example, the plasma display device is installed in a high temperature environment, or the panel 10 is heated to a high temperature. This is the drive mode used when

  In the high temperature driving mode in the present embodiment, the all-cell initialization operation is performed in the first SF, the fourth SF, and the sixth SF, and the selective initialization operation is performed in the other subfields. The initialization voltage Vr at this time is the voltage value VrC as in the room temperature drive mode. As described above, the high-temperature driving mode has a larger number of all-cell initialization operations than the low-temperature driving mode and the normal temperature driving mode.

  Next, the reason for switching and using the three drive modes of the low temperature drive mode, the normal temperature drive mode, and the high temperature drive mode will be described.

  When the panel 10 is at a low temperature, the initializing discharge in the all-cell initializing operation tends to become unstable due to an increase in the discharge start voltage. When the initializing discharge becomes unstable, an erroneous discharge phenomenon such as emission of a discharge cell that should not emit light may occur. This erroneous discharge can be reduced by increasing the initialization voltage Vr in the all-cell initialization subfield.

  Therefore, in this embodiment, the initialization voltage Vr during the all-cell initialization operation in the low temperature driving mode is set to a voltage value VrH that is higher than the voltage value VrC in the normal temperature driving mode, so that the panel 10 is stable even at a low temperature. The all-cell initialization operation is performed, and stable image display is performed.

  On the other hand, when the panel 10 reaches a high temperature, the wall charges of the discharge cells of the non-selected scan electrodes are deprived while the address discharge is generated in the discharge cells of any of the scan electrodes in the address period, and the address discharge is originally performed. When it is desired to generate an address, an address failure may occur in which an address discharge is not generated due to insufficient wall voltage.

  Therefore, in this embodiment, by increasing the number of all-cell initialization operations in the high-temperature drive mode, the insufficient wall charge is supplemented to prevent the occurrence of write failure. Thereby, even if the panel 10 becomes high temperature, a stable image display can be performed.

  As described above, when the panel 10 is at a high temperature or a low temperature, a discharge failure such as an erroneous discharge or an address failure may occur, and there is a risk that the display quality may be deteriorated due to the discharge failure. In order to reduce these discharge defects, the timing generation circuit 55 switches between the three drive modes of the normal temperature drive mode, the high temperature drive mode, and the low temperature drive mode.

  Next, a method for switching the drive mode will be described. The temperature of the panel 10 is naturally influenced by the environmental temperature in which the plasma display device is placed, but the heat generated by the circuit driving the panel, the heat generated by the panel itself, and the image that influences the heat. It varies in a complicated manner depending on the signal. For this reason, it is difficult to accurately detect the panel temperature over the entire panel, and in order to detect the panel temperature without being affected by the constantly changing display image, it is necessary to arrange a large number of temperature sensors in each part of the panel. Is not realistic.

  Therefore, in this embodiment, the temperature of panel 10 is not directly detected, but there is a possibility that an area that needs to be driven in the low temperature driving mode may occur in the display screen of the panel, or the high temperature driving mode. Thus, it is estimated whether there is a possibility that an area that needs to be driven by the above-described driving may occur, and based on the result, the driving mode is switched to display an image with reduced discharge failure.

  FIG. 8 shows the temperature inside the housing (hereinafter abbreviated as “sensor temperature”) θs detected by the temperature sensor 81 in (Embodiment 1) of the present invention and the temperature of the panel 10 (hereinafter “panel temperature”). It is a figure which shows the result of having measured the relationship with (theta) p) (abbreviation), a vertical axis | shaft represents temperature and a horizontal axis represents time. In this measurement, in order to make the sensor temperature θs less susceptible to the local temperature of the panel 10, the temperature sensor 81 is disposed on the circuit board so as not to be in close contact with the panel 10.

  In order to estimate the lowest temperature that the panel 10 can take, an image in which the temperature of the panel 10 can be suppressed to the lowest, that is, an all-cell non-light emitting pattern is displayed. What is necessary is just to measure and investigate the difference with sensor temperature (theta) s.

  FIG. 8A shows the panel temperature θp and the sensor temperature θs when the all-cell non-light emitting pattern is displayed. After the plasma display device is powered on, the sensor temperature θs rises gradually. On the other hand, the panel temperature θp rises more gradually. This is because the panel 10 itself generates little heat because the panel 10 hardly generates electric discharge. In this embodiment, after 10 to 20 minutes, the difference between the sensor temperature θs and the panel temperature θp becomes almost constant, and the panel temperature θp at that time is about 7 ° C. lower than the sensor temperature θs. It was. Therefore, in this embodiment, the low temperature correction value ΔθL is set to 7 ° C., and the temperature obtained by subtracting the low temperature correction value ΔθL from the sensor temperature θs is set as the minimum estimated temperature θL.

  In order to estimate the maximum temperature that the panel 10 can take, an image in which the temperature of the panel 10 becomes the highest, that is, an all-cell light emission pattern is displayed, and the temperature of the highest temperature region of the panel 10 is measured at this time. The difference from the sensor temperature θs may be examined.

  FIG. 8B is a diagram showing the panel temperature θp and the sensor temperature θs when the all-cell light emission pattern is displayed. After the plasma display apparatus is powered on, the sensor temperature θs rises rapidly. On the other hand, the panel temperature θp rises more rapidly. This is because the panel 10 itself generates heat due to the discharge in addition to the large power consumption of the drive circuit. Also in this embodiment, after 10 to 20 minutes, the difference between the sensor temperature θs and the panel temperature θp becomes substantially constant, and the panel temperature θp at that time is about 10 ° C. higher than the sensor temperature θs. It was. Therefore, in this embodiment, the high temperature correction value ΔθH is set to 10 ° C., and the temperature obtained by adding the high temperature correction value ΔθH to the sensor temperature is set as the maximum estimated temperature θH.

In this embodiment, the minimum estimated temperature θL and the maximum estimated temperature θH are set to θL (t) = θs (t) −ΔθLo
θH (t) = θs (t) + ΔθHo
Asking. Here, in order to clearly indicate that the sensor temperature θs, the lowest estimated temperature θL, and the highest estimated temperature θH are functions of time t, they are written as θs (t), θL (t), and θH (t), respectively. ΔθLo and ΔθHo are a low-temperature correction value ΔθL and a high-temperature correction value ΔθH, respectively, and are 7 ° C. and 10 ° C. in the present embodiment, respectively.

  FIG. 9 is a schematic diagram showing the relationship between the lowest estimated temperature θL (t) and the highest estimated temperature θH (t), the low temperature threshold ThL, and the high temperature threshold ThH in (Embodiment 1) of the present invention. is there. As shown in the drawing, if the lowest estimated temperature θL (t) is lower than a preset low temperature threshold ThL, the panel is driven using the low temperature driving mode, and the highest estimated temperature θH (t) is preset. If it is equal to or higher than the high temperature threshold ThH, the panel is driven using the high temperature driving mode, and otherwise the panel is driven in the normal temperature driving mode.

  As described above, in this embodiment, the subfield configuration is switched based on the APL of the image, and the drive mode is switched based on the sensor temperature θs. Therefore, the address discharge is stabilized by increasing the number of all-cell initializations and increasing priming. Conversely, when displaying an image with a low APL, it is considered that the black image display area is wide, so that the number of all-cell initializations is reduced to suppress black luminance and display an image with high contrast.

  Since the drive mode is switched based on the sensor temperature θs, the initialization voltage Vr is set high to stabilize the initialization discharge even when the panel is at a low temperature, and the subfield configuration is switched by the APL described above. Is possible. In addition, even if the panel is hot, the number of times of initializing all cells is increased to prevent the occurrence of write failure, thereby enabling the subfield configuration to be switched by APL.

  Next, a method for controlling the initialization voltage Vr in the all-cell initialization operation will be described. In order to change the initialization voltage Vr, there are various methods such as increasing the voltage Vi1 of the scan electrode SC1 in FIG. 5 or increasing the voltage Vi2 by increasing the voltage Vi2 from the voltage Vi1 with a steep rising slope. Can be considered. Hereinafter, an example thereof will be described with reference to the drawings.

  FIG. 10 is a circuit diagram of scan electrode driving circuit 53 in (Embodiment 1) of the present invention. Scan electrode driving circuit 53 includes sustain pulse generation circuit 100 that generates a sustain pulse, initialization waveform generation circuit 300 that generates an initialization waveform, and scan pulse generation circuit 400 that generates a scan pulse.

  The sustain pulse generating circuit 100 includes a power recovery circuit 110 for recovering and reusing power when driving the scan electrode 22, a switching element SW1 for clamping the scan electrode 22 to the voltage Vs, and the scan electrode 22. And switching element SW2 for clamping the voltage to 0 (V). The scan pulse generation circuit 400 sequentially applies scan pulses to the scan electrodes 22 in the address period. Scan pulse generation circuit 400 outputs the voltage waveform of sustain pulse generation circuit 100 or initialization waveform generation circuit 300 as it is during the initialization period and the sustain period.

  The initialization waveform generation circuit 300 includes Miller integration circuits 310 and 320, generates the above-described initialization waveform, and controls the initialization voltage Vr in the all-cell initialization operation. Miller integrating circuit 310 includes FET1, capacitor C1, and resistor R1, and generates a ramp waveform voltage that gradually increases in a ramp shape to a predetermined initialization voltage Vr. Miller integrating circuit 320 includes FET2, capacitor C2, A ramp waveform voltage that has a resistance R2 and gradually decreases in a ramp shape up to a voltage Vi4 is generated. In FIG. 10, the input terminals of Miller integrating circuits 310 and 320 are shown as terminal IN1 and terminal IN2, respectively.

  In this embodiment, a Miller integration circuit using a FET that is practical and has a relatively simple configuration is employed as the initialization waveform generation circuit 300. However, the present invention is not limited to this configuration. Any circuit may be used as long as it can generate the ramp waveform voltage while controlling the initialization voltage Vr.

  Next, the operation of the initialization waveform generation circuit 300 will be described. FIG. 11 is a timing chart for explaining the operation of scan electrode driving circuit 53 in the all-cell initializing period in (Embodiment 1) of the present invention. Here, the drive voltage waveform for performing the all-cell initialization operation is divided into four periods indicated by T1 to T4, and each period will be described.

  In the following description, it is assumed that the voltage Vi1, the voltage Vi3, and the voltage Vi3 'are all equal to the voltage Vs. In the following description, the operation of turning on the switching element is turned on and the operation of turning off the switching element is expressed as off.

(Period T1)
First, switching element SW1 of sustain pulse generation circuit 100 is turned on. Then, the voltage Vs is applied to the scan electrode 22 via the switching element SW1. Thereafter, the switching element SW1 is turned off.

(Period T2)
Next, the input terminal IN1 of the Miller integrating circuit 310 is set to “high level”. Specifically, for example, a voltage of 15 (V) is applied to the input terminal IN1. Then, a constant current flows from the resistor R1 toward the capacitor C1, the source voltage of the FET 1 rises in a ramp shape, and the output voltage of the scan electrode driving circuit 53 starts to rise in a ramp shape. This voltage increase continues while the input terminal IN1 is at “high level”.

  When the output voltage rises to the required initialization voltage Vr, the input terminal IN1 is then set to “low level”.

  In this way, from the voltage Vs that is equal to or lower than the discharge start voltage (equal to the voltage Vi1, the voltage Vi3, and the voltage Vi3 ′ in the present embodiment), the initialization voltage Vr that exceeds the discharge start voltage (in the present embodiment, A ramp voltage that gradually increases toward the voltage Vi2 is applied to the scan electrode 22.

  At this time, if the time tr during which the input terminal IN1 is set to “high level” is lengthened, the initialization voltage Vr can be increased, and if the time tr is shortened, the initialization voltage Vr can be decreased.

(Period T3)
Next, switching element SW1 of sustain pulse generation circuit 100 is turned on. Then, the voltage of the scan electrode 22 is lowered to the voltage Vs. Thereafter, the switching element SW1 is turned off.

(Period T4)
Next, the input terminal IN2 of the Miller integrating circuit 320 is set to “high level”. Specifically, for example, a voltage of 15 (V) is applied to the input terminal IN2. Then, a constant current flows from the resistor R2 toward the capacitor C2, the drain voltage of the FET 2 decreases in a ramp shape, and the output voltage of the scan electrode driving circuit 53 starts to decrease in a ramp shape. Then, after the output voltage reaches the negative voltage Vi4, the input terminal IN2 is set to “low level”.

  As described above, the ramp voltage that gradually increases from the voltage Vi1 that is equal to or lower than the discharge start voltage to the initialization voltage Vr that exceeds the discharge start voltage is applied to the scan electrode 22, and then the voltage Vi3 to the voltage A ramp voltage that gently falls toward Vi4 is applied.

  In FIG. 11, in order to apply the initialization voltage VrH, the time tr for setting the input terminal IN1 of the scan electrode driving circuit 53 in FIG. 10 to “high level” is lengthened, and in order to apply the initialization voltage VrC, the time This can be realized by shortening tr.

(Embodiment 2)
Next, in consideration of the effect that the discharge characteristics change as the cumulative usage time of the panel becomes longer, the above-described control can be performed under optimum conditions regardless of the cumulative usage time from the initial use of the plasma display device. Will be described.

  The structure of the panel, the outline of the drive voltage waveform, and the like in this embodiment are the same as in (Embodiment 1). The present embodiment is different from (Embodiment 1) in that it includes an accumulated time measuring circuit that measures the total time (hereinafter abbreviated as “energized accumulated time”) when power is supplied to the plasma display device. This is that the number of all-cell initializations and the initialization voltage are controlled based on the APL of the image signal and the sensor temperature θs and the accumulated energization time of the panel.

  FIG. 12 is a circuit block diagram of plasma display device 1 according to (Embodiment 2) of the present invention. The accumulated time measuring circuit 83 has a generally known integration function in which the numerical value increases by a certain amount every unit time, measures the energized accumulated time, and outputs it to the timing generation circuit 55.

  The timing generation circuit 55 determines a drive mode based on the minimum estimated temperature θL (t) and the maximum estimated temperature θH (t) output from the temperature estimation circuit 58, and the subfield configuration based on the APL of the image signal in the drive mode. In addition, the initialization voltage Vr is controlled to increase as the energization accumulated time becomes longer. Then, various timing signals for driving the panel 10 are generated and output to the respective circuit blocks.

  Other circuit blocks are the same as those in the first embodiment.

  Next, the relationship between the energization accumulation time and the initialization voltage Vr will be described. FIG. 13 is a schematic diagram showing the relationship between the panel energization accumulation time and the discharge start voltage in (Embodiment 2) of the present invention. The discharge start voltage gradually increases as the panel energization accumulation time increases. It shows that there is a tendency to become. Since the discharge characteristics change with time in this way, when the initialization voltage Vr is set with reference to the discharge start voltage of the panel having a short energization time, the discharge start voltage increases as the energization time increases, and the discharge start voltage On the other hand, since the initialization voltage Vr is relatively low, the initialization discharge is weakened, and there is a possibility that the initialization discharge becomes insufficient, such as insufficient wall voltage being formed or insufficient priming. Conversely, if the initialization voltage Vr is set to a high value in advance in anticipation of changes over time in the discharge characteristics, the initialization discharge becomes stronger than necessary in a panel with a short energization time, which is related to image display. There is a risk that the intensity of light emission increases and black luminance increases and contrast decreases.

  However, in the present embodiment, the accumulated time measuring circuit 83 is provided, and the energized accumulated time is measured and controlled so that the initialization voltage Vr increases as the energized accumulated time becomes longer. Therefore, it is possible to display an image with high contrast without destabilizing the initializing discharge regardless of the energization accumulation time from the initial manufacturing stage of the plasma display device.

  There are various methods for controlling the initialization voltage Vr based on the energization accumulation time, such as continuously increasing the initialization voltage Vr as the energization accumulation time increases. Provides a plurality of cumulative time threshold values, compares the cumulative current time output from the cumulative time measurement circuit 83 with the cumulative time threshold value, and initializes each time the cumulative current time exceeds the cumulative time threshold value. The voltage Vr is increased. FIG. 14 is a diagram showing a method of controlling the initialization voltage in (Embodiment 2) of the present invention. FIG. 14 (a) shows the relationship between the energization accumulated time and the initialization voltage Vr, and FIG. ) Shows the relationship between the energization accumulation time and the contrast ratio. Thus, in this embodiment, three cumulative time threshold values of 650 hours, 850 hours, and 1000 hours are provided, and when the energization cumulative time exceeds 650 hours, the initialization voltage Vr is increased by 5 (V). . The increase of the initialization voltage is performed not only in the normal temperature driving mode but also in the low temperature driving mode and the high temperature driving mode, and is performed regardless of the APL value. When the energization accumulated time exceeds 850 hours, the initialization voltage Vr is further increased by 5 (V). When the cumulative energization time exceeds 1000 hours, the initialization voltage Vr is further increased by 5 (V).

  As described above, in the present embodiment, the initialization voltage Vr is also increased according to the increase of the discharge start voltage accompanying the increase of the energization accumulated time, so that the contrast is high and stable image display is possible regardless of the energization accumulated time. It has become.

  Although the present embodiment has been described on the assumption that the cumulative time threshold value is uniformly set and the initialization voltage Vr is uniformly increased in all the drive modes of the low temperature drive mode, the normal temperature drive mode, and the high temperature drive mode. The present invention is not limited to this configuration. For example, the accumulation time threshold value may be set individually for each of the drive modes, or the initialization voltage Vr may be increased with an individual voltage width for each of the drive modes.

  Further, since it is considered that if the initialization voltage Vr is high, it is unlikely to be affected by the rise of the discharge start voltage due to the change with time. Therefore, the increase width of the initialization voltage may be made smaller as the initialization voltage Vr is higher.

  Further, in the present embodiment, the operation for increasing the initialization voltage Vr by comparing the energization accumulated time and the accumulated time threshold is performed when the plasma display device is turned on, and the accumulated energization time is accumulated during image display. The initialization voltage Vr is not increased even if the time threshold value is exceeded. This is to avoid a change in black luminance during image display. However, if the initialization voltage Vr is gradually increased to such an extent that the change in black luminance is not so great, the initialization voltage Vr may be increased when the energization accumulation time becomes equal to or greater than the accumulation time threshold.

  In (Embodiment 1) and (Embodiment 2) of the present invention, if a hysteresis characteristic is provided when increasing / decreasing the number of all-cell initializations, frequent fluctuations in black luminance can be suppressed, thereby further displaying an image. Quality can be improved.

  First, a method for providing a hysteresis characteristic when switching the drive mode will be described. FIG. 15 is a diagram showing an example of the relationship between the maximum estimated temperature θH and the high temperature threshold ThH in the embodiment of the present invention. Within one field period, the normal cell drive mode has 2 times for all cell initialization and the high temperature drive mode has 3 times for all cell initialization. Therefore, as shown in FIG. If it fluctuates frequently across the threshold value ThH, the number of all-cell initializations also fluctuates frequently, and the change in black luminance becomes conspicuous. Therefore, in the present embodiment, as shown in FIG. 15B, two high temperature threshold values ThH1 and ThH2 are provided, and the high temperature threshold value ThH1 when switching from the normal temperature driving mode to the high temperature driving mode is set to the high temperature driving. By setting the temperature higher than the high temperature threshold ThH2 for switching from the mode to the room temperature drive mode to have hysteresis characteristics, frequent switching of the drive mode is prevented. Similarly, the low temperature threshold value can have hysteresis characteristics.

  When the number of all-cell initializations is increased / decreased based on APL, hysteresis characteristics can be given in the same way. FIG. 16 is a diagram showing an example of the relationship between APL and the number of times of all cell initialization in the embodiment of the present invention. In one field period, when the APL is 6% or more, the number of times of all-cell initialization is 2 times, and when it is less than 6%, the number of times of all-cell initialization is 1 time, so as shown in FIG. If the APL frequently fluctuates between 6%, the number of all cell initializations also fluctuates frequently. Therefore, as shown in FIG. 16B, two threshold values, for example, 5% and 7%, are provided for the APL, and the threshold when the number of all cell initializations is increased from once to twice. Hysteresis characteristics can be provided by setting the value to 7% and the threshold value for reducing the number of all cell initializations from 2 to 1 to 5%.

  Thus, by providing hysteresis characteristics when changing the all-cell initialization count, it is possible to prevent the all-cell initialization count from changing frequently and to prevent the black luminance from fluctuating frequently.

  In (Embodiment 1), the method of controlling the number of all-cell initializations and the initialization voltage based on not only the sensor temperature θs but also the APL of the image signal has been described. (Embodiment 1) Since the control based on the sensor temperature θs is the main focus, the control based on the APL of the image signal may be omitted.

  In the embodiment of the present invention, the xenon partial pressure of the discharge gas is set to 10%. However, the drive voltage corresponding to the panel may be set even if the xenon partial pressure is other than that.

  Furthermore, the specific numerical values used in the embodiments of the present invention are merely examples, and can be appropriately set to optimal values according to the characteristics of the panel, the specifications of the plasma display device, and the like. desirable.

  Since the present invention enables stable high-speed writing while suppressing an increase in black luminance over a wide temperature range, it is useful as a panel driving method and a plasma display device used for a wall-mounted television or a large monitor.

The exploded perspective view which shows the structure of the panel in (Embodiment 1) of this invention Electrode arrangement of the panel Circuit block diagram of drive circuit for driving the panel The figure which shows the attachment position of the temperature sensor of the plasma display apparatus in (Embodiment 1) of this invention. Drive voltage waveform diagram applied to each electrode of the panel The figure which shows the subfield structure in (Embodiment 1) of this invention. The figure which shows the subfield structure in (Embodiment 1) of this invention. The figure which shows the result of having measured the relationship between the temperature inside the housing | casing which the temperature sensor in (Embodiment 1) of this invention detected, and the temperature of a panel. Schematic showing the relationship between minimum estimated temperature, maximum estimated temperature and low temperature threshold, and high temperature threshold in (Embodiment 1) of the present invention Circuit diagram of scan electrode drive circuit according to (Embodiment 1) of the present invention Timing chart for explaining operation of scan electrode driving circuit in all-cell initializing period in (Embodiment 1) of the present invention Circuit block diagram of plasma display device according to (Embodiment 2) of the present invention The schematic diagram which showed the relationship between the energization accumulation time of the panel and discharge start voltage in (Embodiment 2) of this invention The figure which shows the control method of the initialization voltage in (Embodiment 2) of this invention The figure which shows an example of the relationship between the highest estimated temperature and high temperature threshold value in embodiment of this invention The figure which shows an example of the relationship between APL and all cell initialization frequency in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma display apparatus 10 Panel 21 (made of glass) Front plate 22 Scan electrode 23 Sustain electrode 24, 33 Dielectric layer 25 Protective layer 28 Display electrode pair 31 Back plate 32 Data electrode 34 Partition 35 Phosphor layer 51 Image signal processing circuit 52 Data electrode drive circuit 53 Scan electrode drive circuit 54 Sustain electrode drive circuit 55 Timing generation circuit 57 APL detection circuit 58 Temperature estimation circuit 81 Temperature sensor 83 Cumulative time measurement circuit 86 Thermal conduction sheet 87 Aluminum chassis 88 Boss material 89 Circuit board 100 Maintenance Pulse generation circuit 110 Power recovery circuit 300 Initialization waveform generation circuit 310, 320 Miller integration circuit 400 Scanning pulse generation circuit

Claims (3)

Within one field period, all-cell initializing subfields that generate initializing discharges for all discharge cells that perform image display in the initializing period, and discharges that have generated sustain discharges in the immediately preceding subfield during the initializing period A method for driving a plasma display panel comprising a selective initialization subfield for selectively generating an initialization discharge in a cell,
An initialization voltage for generating an initializing discharge can be varied in the all-cell initializing subfield, and at least three driving modes different in at least one of the number of all-cell initializing subfields and the initializing voltage are switched. Configured to drive the plasma display panel,
Based on the temperature around the plasma display panel, estimate the lowest estimated temperature when displaying the all-cell non-emission pattern of the plasma display panel and the highest estimated temperature when displaying the all-cell emission pattern ,
A low temperature drive mode selected when the minimum estimated temperature is lower than a predetermined low temperature threshold, a high temperature drive mode selected when the maximum estimated temperature is equal to or higher than a predetermined high temperature threshold, and the minimum estimated temperature At least a room temperature drive mode that is selected when the maximum estimated temperature is less than the high temperature threshold,
The number of all cell initialization subfields in the high temperature driving mode is set to be larger than the number of all cell initialization subfields in the room temperature driving mode, and the initialization voltage in the low temperature driving mode is set in the room temperature driving mode. A method for driving a plasma display panel, wherein the voltage value is set to be higher than the initialization voltage . An APL detection unit that detects an average luminance in one field period or one frame period of an image signal;
The plasma display panel driving method according to claim 1, wherein the number of the all-cell initializing subfields is changed based on the average luminance detected by the APL detecting unit. A plasma display panel having a plurality of discharge cells each having a display electrode pair including a scan electrode and a sustain electrode;
A temperature estimation circuit that has a temperature sensor and estimates the lowest estimated temperature and the highest estimated temperature that the plasma display panel can take based on the temperature detected by the temperature sensor;
A driving circuit for driving the plasma display panel,
One field includes an initializing period for generating an initializing discharge in the discharge cell, an addressing period for generating an addressing discharge in the discharge cell, and a sustaining period for generating a sustaining discharge in the discharge cell that has generated the addressing discharge. Comprising a plurality of subfields having
Within one field period, a sustain discharge is generated in an all-cell initializing subfield that generates an initializing discharge for all discharge cells that perform image display in the initializing period, and an immediately preceding subfield in the initializing period. A selective initializing subfield for selectively generating initializing discharge in the discharged cells,
The drive circuit can increase or decrease the number of all-cell initialization subfields, and can change an initialization voltage for generating an initialization discharge in the all-cell initialization subfield. The plasma display panel is driven by switching at least three types of driving modes that differ in at least one of the number and the initialization voltage, and all the cells that the plasma display panel can take based on the temperature around the plasma display panel Estimate the lowest estimated temperature when the non-emission pattern is displayed and the highest estimated temperature when the all-cell emission pattern is displayed,
A low temperature drive mode selected when the minimum estimated temperature is lower than a predetermined low temperature threshold, a high temperature drive mode selected when the maximum estimated temperature is equal to or higher than a predetermined high temperature threshold, and the minimum estimated temperature At least a room temperature drive mode that is selected when the maximum estimated temperature is less than the high temperature threshold,
The number of all cell initialization subfields in the high temperature driving mode is set to be larger than the number of all cell initialization subfields in the room temperature driving mode, and the initialization voltage in the low temperature driving mode is set in the room temperature driving mode. A plasma display device, wherein the voltage value is set higher than the initialization voltage .

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